Dilated cardiomyopathy, or DCM, is characterized by enlargement and weakening of the ventricles, and cardiac fibrosis — the excessive accumulation of extracellular matrix proteins such as collagens — is a major driver of that adverse remodeling. Fibrosis stiffens the heart wall, impairs its ability to fill with blood, and progressively worsens function. But fibrosis is not produced by a single, uniform population of cells. Cardiac fibroblasts occupy dynamic, injury-dependent transcriptional states, and single-cell and single-nucleus profiling has revealed marked stromal heterogeneity in both healthy and diseased myocardium. Activated fibroblasts can be sparse in non-failing hearts yet enriched in cardiomyopathy, and previous work has implicated the transcription factor MEOX1 as a regulator of fibroblast activation. What remained uncertain was which human DCM fibroblast state is most reproducibly enriched across cohorts, and whether its disease association is stronger than that of the conventional ACTA2-high myofibroblast state that has dominated the literature.

To answer that question, the study used a prespecified discovery-and-validation design built entirely on publicly available data. The discovery cohort, GSE183852, contained left-ventricular nuclei from 25 non-failing donor hearts and 13 DCM hearts. The external validation cohort, SCP1303, contained 16 normal and 11 DCM hearts, with hypertrophic cardiomyopathy samples excluded from the primary comparison. Fibroblasts from the discovery cohort — 49,124 nuclei in total — were independently reclustered in Seurat using log normalization, 2,500 variable features, 30 principal components, a shared-nearest-neighbor graph, and Louvain clustering at resolution 0.5, with a fixed random seed to ensure reproducibility. Critically, the author treated the donor, not the individual nucleus, as the statistical unit of inference, a decision that guards against the false discoveries that arise when thousands of nuclei from one patient are mistakenly counted as independent biological replicates.

The reclustering resolved multiple fibroblast states and revealed substantial compositional variation between donors. One cluster stood out: cluster two showed high expression of MEOX1 and FAP together with relatively low ACTA2, the gene encoding alpha-smooth muscle actin that marks the classical contractile myofibroblast. The study is careful to note that ACTA2-low is a relative property — ACTA2 was detected in 14.7 percent of cluster-two nuclei versus 57.3 percent in the discrete ACTA2-high cluster 16 — and does not imply absent expression or a lack of overall ACTA2 induction in disease. Cluster two nonetheless retained clear extracellular-matrix features, expressing FN1, POSTN, COL1A1 and COL3A1, and an unbiased marker analysis surfaced RFX2, CYR61, FOS, EGR1, DDAH1, CTGF, FAP and MEOX1 among its leading genes. The state was therefore defined by the combined three-marker pattern rather than any single gene.

The quantitative case for disease enrichment rests on donor-level proportions. Cluster two made up a median 5.81 percent of fibroblasts in DCM hearts versus 0.28 percent in donor hearts, a difference that was highly significant after false-discovery-rate correction. The mean DCM-minus-donor difference was 0.165, with a 95 percent confidence interval of 0.035 to 0.349 derived from 10,000 iterations of donor bootstrap resampling. Perhaps most tellingly, sequentially omitting each of the 38 donors one at a time never flipped the direction of the effect, which stayed within a range of 0.102 to 0.179. Sensitivity analyses across clustering resolutions showed that while the default state merged into broader compartments at lower resolutions, higher-resolution counterparts retained disease enrichment with p-values below 2 × 10⁻⁶. By contrast, the ACTA2-high cluster 16 showed only a smaller, non-significant abundance difference between groups.

Covariate modeling added nuance rather than contradiction. Heteroscedasticity-consistent HC3 linear models estimated a DCM coefficient of 0.165 unadjusted, 0.166 after adjusting for sex, and 0.184 after adjusting for both sex and ordinal age tertile — the finest age granularity the source data allowed. The effect magnitude was preserved in every model, but the confidence intervals marginally crossed zero, and the author explicitly declines to claim covariate-independent statistical significance. This kind of restraint is uncommon in reanalysis studies and reflects the modest number of donors available: with 38 hearts in the discovery cohort, even a robust effect can produce intervals that graze the null.

External validation in the independent SCP1303 cohort strengthened the finding while also defining its boundary. The author-annotated activated fibroblast population, FB-ActFB, was far more abundant in DCM than in normal hearts — a median of 24.11 percent versus 5.16 percent of fibroblasts — with a mean difference of 0.192 and a bootstrap confidence interval of 0.144 to 0.256. All 27 leave-one-donor-out estimates remained positive, and the sex-adjusted coefficient was 0.199 with a p-value of 6.61 × 10⁻⁷. The external state showed concordant MEOX1 and FAP expression, but ACTA2 was not available in the retained external marker summary, and validation relied on the source study’s annotations rather than frozen one-to-one label transfer. The author therefore concludes that the replication supports a shared activation program and abundance shift, not a complete reproduction of the three-marker phenotype or identical cellular identity.

Beyond the state itself, donor-pseudobulk differential expression — in which raw fibroblast counts are summed within each donor before testing — identified several genes elevated in DCM fibroblasts after false-discovery-rate correction. DDAH1 led the list with an adjusted log2 fold change of 2.01, followed by MEOX1 at 2.29 and FAP at 1.89; POSTN, TGFBI, CTGF and COL1A2 also passed correction. Within discovery cluster two, nuclei positive for DDAH1 showed higher extracellular-matrix scores than DDAH1-negative nuclei in paired donor summaries. DDAH1, an enzyme involved in nitric oxide metabolism, has previously been linked to cardiac hypertrophy and remodeling in animal models, which makes it a biologically plausible candidate. The study is emphatic, however, that DDAH1 is a prioritized state-associated candidate, not an established causal regulator, and it was deliberately excluded from the state-defining marker panel to avoid circularity.

The extracellular-matrix evidence itself proved partly method-dependent, a finding the author reports transparently. The donor-pseudobulk ECM score was significantly higher in DCM hearts, with a Mann–Whitney p-value of 0.00975, whereas the cell-derived donor mean showed the same positive direction without reaching significance. The two scoring approaches were nonetheless strongly correlated across donors, with a Spearman correlation of 0.891. Whole-fibroblast pseudobulk differences can reflect both shifts in state composition and expression changes within states, so they cannot by themselves establish cluster-specific regulation. ACTA2, notably, showed a modest overall increase in DCM fibroblasts, reinforcing that the ACTA2-low label describes a relative cluster phenotype rather than a claim that canonical myofibroblasts are absent from the diseased heart.

The study’s limitations are acknowledged candidly: it is a secondary analysis without spatial, protein-level or functional validation; age information was incomplete in both cohorts; reliable etiologic subdivisions of DCM were unavailable; and public-cohort processing differences precluded exact state transfer between datasets. Still, the work delivers something the field genuinely needs — a technically controlled, hypothesis-generating target for prospective experiments. The author proposes that multiplex tissue imaging should test the spatial coexistence of MEOX1, FAP, ACTA2 and DDAH1 in diseased myocardium, while fibroblast perturbation studies should determine whether DDAH1 alters collagen synthesis, matrix organization or state transitions. If those experiments pan out, a fibroblast state first glimpsed in reprocessed public data could point toward new anti-fibrotic strategies for a disease that currently has few options beyond transplantation.

Subject of Research: Identification of a disease-associated MEOX1+FAP+ACTA2-low fibroblast state in dilated cardiomyopathy using cross-cohort single-nucleus RNA sequencing

Article Title: Cross-cohort single-nucleus transcriptomic identification of a MEOX1+FAP+ACTA2-low extracellular matrix-remodeling fibroblast state in dilated cardiomyopathy

Article References: Li, Y. (2026). Cross-cohort single-nucleus transcriptomic identification of a MEOX1+FAP+ACTA2-low extracellular matrix-remodeling fibroblast state in dilated cardiomyopathy. Frontiers in Genetics, 17, Article 1987893. https://doi.org/10.3389/fgene.2026.1987893

Image Credits: AI Generated

DOI: 10.3389/fgene.2026.1987893

Keywords: dilated cardiomyopathy, cardiac fibrosis, fibroblasts, single-nucleus RNA sequencing, MEOX1, FAP, ACTA2, DDAH1, extracellular matrix, pseudobulk differential expression, biomarkers, Cross-cohort

To understand why this validation matters, it helps to appreciate what mitochondria actually do and why their failure produces such bewildering symptoms. These tiny compartments inside nearly every human cell descended from ancient free-living bacteria that entered into a symbiotic partnership with our single-celled ancestors more than a billion years ago. That evolutionary history left mitochondria with their own small genome, separate from the DNA in the cell nucleus, and it means that defects can arise from mutations in either of two genetic systems. When mitochondria falter, the tissues that demand the most energy pay the price first: the brain, heart, muscles, eyes, and kidneys. This explains why a single underlying disorder can present as seizures and developmental delay in one child, cardiomyopathy in another, and progressive muscle weakness in a third, often leaving families shuffled among specialists for years before anyone assembles the full picture.

The scale of the diagnostic problem is difficult to overstate. With an estimated prevalence of roughly one in five thousand people, mitochondrial disease is not as rare as many conditions that receive far more research attention, yet it remains one of the most difficult groups of disorders to pin down. The genetic landscape is enormous: hundreds of genes, scattered across both the nuclear genome and the mitochondrial genome, have been implicated, and new disease genes continue to be described. Clinical features overlap with far more common conditions, and symptoms can appear at any age, from the newborn period to late adulthood. For decades, the diagnostic gold standard combined a characteristic pattern of findings on muscle biopsy with biochemical measurements of respiratory chain function, but obtaining that tissue required surgery under general anesthesia, a serious consideration for fragile patients and an outright barrier for many others.

The arrival of affordable genomic sequencing changed the first step of the diagnostic journey for most patients. Whole genome and whole exome sequencing can now scan the entire genetic code for variants in known mitochondrial genes, and for roughly half to two-thirds of patients this approach delivers a definitive molecular answer. But that statistic cuts both ways: a substantial minority of patients, potentially thousands of families, are left with results that are ambiguous or entirely uninformative. Sequencing excels at finding changes in the DNA sequence, yet it cannot reveal whether a particular variant actually disrupts mitochondrial function, whether two variants inherited together produce disease, or whether the problem lies in a gene not yet recognized as mitochondrial. Variants of uncertain significance accumulate in reports, and clinicians are left to weigh ambiguous genetic data against a clinical picture that may not fit any established syndrome.

This is precisely the gap that functional testing is designed to close. Rather than reading the genetic blueprint, functional assays interrogate the finished machinery itself: how efficiently the respiratory chain shuttles electrons, how well the complexes that generate cellular energy assemble and operate, and how cells respond to metabolic stress. The new study, accepted for publication in EMBO Molecular Medicine, represents the first comprehensive evaluation of how these assays perform in real-world clinical use, measuring both how often they contribute to a diagnosis and how accurately they separate affected patients from unaffected ones. That distinction matters, because a test can be technically impressive in a research setting yet fail the practical standards of sensitivity and specificity that clinical medicine demands.

The collaborative architecture of the study deserves particular attention. By drawing samples from more than thirty medical centers spanning North America, Europe, and Australia and New Zealand, the investigators assembled a cohort diverse enough to reflect the true heterogeneity of mitochondrial disease as it presents in clinics around the world. Multicenter studies of this kind are rare in a field built around small, specialized referral centers, and they carry real weight: a diagnostic test validated on samples from dozens of institutions is far more convincing than one demonstrated only in the laboratory that invented it. The breadth of the collection also allowed the researchers to assess performance across different disease subtypes and age groups rather than in a narrow, artificially homogeneous population.

The central finding, that fibroblasts grown from a small skin biopsy can often supply the diagnostic information previously requiring muscle or liver tissue, rests on a biological insight that has matured over decades. Skin cells are remarkably cooperative in the laboratory: a punch biopsy about the size of a pencil eraser, taken under local anesthesia in an outpatient setting, yields cells that can be expanded indefinitely in culture dishes. Mitochondrial dysfunction is generally expressed throughout the body’s tissues, so fibroblasts frequently carry the same biochemical fingerprint as muscle or liver, the tissues traditionally sampled. Culturing the cells also offers an advantage that fresh tissue does not: the laboratory can grow enough material to repeat assays, run additional tests as new methods emerge, and bank samples for future reanalysis as knowledge advances.

For patients, the practical implications are substantial. A skin biopsy can be performed in a clinic visit with local anesthetic, avoiding the operating room, the general anesthetic, and the postoperative recovery that muscle and liver biopsies entail. General anesthesia itself carries particular risks for patients with mitochondrial disease, since metabolic stress during surgery can precipitate clinical deterioration, a concern that has long made invasive diagnostics a genuinely dangerous proposition for the sickest patients. Removing that barrier means that patients who previously might have deferred testing, or whose physicians hesitated to recommend surgery, can now pursue a diagnosis with far lower stakes. It also opens the door to testing at centers far from the few hospitals that perform specialized tissue biopsies, since a skin sample can be shipped to a reference laboratory.

The translation of research assays into routine clinical service is often the slowest step in medical progress, and the Colorado team has moved it forward in parallel with the science. Nearly all of the functional tests examined in the publication are now offered through the Mitochondrial Diagnostic Laboratory within the Department of Pathology and Laboratory Medicine at Children’s Colorado, which has grown into one of the largest providers of mitochondrial functional testing in North America, receiving samples from medical centers throughout the United States and Canada. This clinical infrastructure matters because it converts a published finding into something a physician anywhere can actually order, and because the volume of samples flowing through the laboratory feeds back into continuous refinement of the assays themselves.

The study also benefited from sustained public investment in rare disease research infrastructure. Support from the National Institutes of Health through the North American Mitochondrial Disease Consortium, a network established to link patients, clinicians, and investigators across institutions, made a study of this geographic scope feasible. Consortia of this kind solve a fundamental problem in rare disease research: no single center sees enough patients to power meaningful studies, but a coordinated network can. Funding from the Children’s Hospital Colorado Foundation and the University of Colorado Foundation supplemented the federal support, illustrating how philanthropy often bridges the gap for conditions that fall outside commercial incentives.

Looking ahead, the most promising model is likely to be complementary rather than competitive: genetic sequencing to identify candidate variants, followed by functional testing to confirm or exclude their significance. When a sequencing report lists several variants of uncertain significance, demonstrating that the patient’s cells actually show impaired respiratory chain function can tip the balance toward a diagnosis, while normal function in the relevant pathway can redirect the search. Conversely, a clear functional defect can guide which of the many uncertain variants deserves attention. This interplay between reading the genome and testing its output reflects a broader shift in genetics toward multidisciplinary interpretation, and for mitochondrial disease it may finally shorten journeys that families have too often measured in decades.

Subject of Research: Functional diagnostic testing of fibroblasts from skin biopsies for mitochondrial disease diagnosis

Article Title: International study validates less invasive approach to diagnosing mitochondrial disease

Article References: International study validates less invasive approach to diagnosing mitochondrial disease. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: mitochondrial disease, skin biopsy, fibroblasts, functional testing, genetic testing, Children's Hospital Colorado, EMBO Molecular Medicine, rare disease, diagnosis, mitochondria, NAMDC, precision medicine

Researchers from Xi’an Jiaotong University have identified a novel signaling pathway that drives this abnormal tissue growth, offering a new avenue for targeted therapies. Published in the journal iScience, the study reveals that the protein CD147, also known as Basigin or EMMPRIN, plays a critical role in promoting keloid formation. By activating the centromere protein F (CENPF) signaling pathway, CD147 stimulates the hyperproliferation of keloid fibroblasts, the primary cell type responsible for the excessive deposition of extracellular matrix in these lesions. This discovery bridges a gap in our understanding of how specific molecular signals translate into the tumor-like growth patterns observed in keloids.

CD147 is a glycosylated transmembrane protein that has previously been associated with aggressive human cancers, where it promotes cell proliferation and invasion. In the context of keloids, the study demonstrates that CD147 is significantly overexpressed in keloid fibroblasts compared to normal fibroblasts. The researchers found that both membrane-bound CD147 and its soluble form, sCD147, are elevated in keloid tissues. Through co-immunoprecipitation assays, they confirmed that soluble CD147 can bind directly to membrane-bound CD147 on the surface of fibroblasts, triggering intracellular signaling cascades that enhance cell bioactivity. This homophilic interaction suggests that CD147 functions in both autocrine and paracrine manners, amplifying the proliferative signals within the keloid microenvironment.

To investigate the downstream effects of CD147 activation, the team utilized recombinant human CD147 protein to treat keloid fibroblasts in vitro. The results showed a dose-dependent increase in cell proliferation, migration, and invasion. Western blot analysis revealed that CD147 stimulation activated the PI3K-Akt signaling pathway, a well-known regulator of cell survival and growth. Additionally, the treatment upregulated the expression of integrin β1, matrix metalloproteinase-2 (MMP-2), and α-smooth muscle actin (α-SMA). These markers are indicative of myofibroblast activation and increased extracellular matrix remodeling, processes that are central to the fibrotic nature of keloids. The activation of these pathways by CD147 provides a mechanistic link between the surface protein and the aggressive behavior of keloid fibroblasts.

Conversely, inhibiting CD147 with the small-molecule compound AC-73 reversed these pathological phenotypes. The inhibitor suppressed fibroblast proliferation in a time- and concentration-dependent manner, reduced the secretion of soluble CD147 and MMP-2, and increased the rate of apoptosis. TUNEL assays confirmed that AC-73 treatment led to a significant increase in apoptotic cells, suggesting that blocking CD147 restores the balance between cell growth and cell death. Furthermore, the inhibitor downregulated the expression of integrin β1, MMP-2, and α-SMA, effectively reversing the myofibroblast-like characteristics of the keloid fibroblasts. These findings highlight the potential of CD147 inhibitors as therapeutic agents for managing keloid progression.

To uncover the specific molecular targets of CD147, the researchers performed RNA sequencing on keloid fibroblasts treated with AC-73. The analysis identified 2,646 differentially expressed genes, with CENPF emerging as the most significantly downregulated gene. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that these genes were primarily involved in cell cycle regulation, DNA replication, and the PI3K-Akt pathway. Gene ontology analysis further indicated that the affected genes were enriched in biological processes such as chromosome segregation and mitotic cell cycle phase transition. This bioinformatics approach pinpointed CENPF as a key mediator of CD147-driven proliferation, linking the surface receptor to fundamental cellular processes governing division and growth.

CENPF is a nuclear matrix protein that plays a crucial role in regulating mitosis and the cell cycle. Its expression peaks during the G2 and M phases of the cell cycle, and it is rapidly degraded upon mitotic completion. In keloid tissues, CENPF was found to be significantly overexpressed compared to normal skin, correlating with the increased proliferative capacity of keloid fibroblasts. The study demonstrated that CD147 inhibition led to a decrease in CENPF expression, which in turn arrested the cell cycle at the G2/M phase. This arrest was accompanied by changes in the expression of p53 signaling-related proteins, including an increase in p53 and Bax levels and a decrease in MDM2 expression. MDM2 is a negative regulator of p53, and its reduction suggests that the p53 tumor suppressor pathway is reactivated in the absence of CD147 signaling.

Further experiments using small interfering RNA to knock down CENPF expression confirmed its functional role in keloid fibroblast proliferation. Silencing CENPF reduced cell viability and induced G2/M phase arrest, mirroring the effects of CD147 inhibition. Importantly, CENPF knockdown rescued the downregulation of p53 and Bax induced by CD147, indicating that CENPF acts downstream of CD147 to suppress the p53 pathway. The downregulation of cell cycle regulators such as cyclin A1, cyclin B1, and CDK1 upon CENPF knockdown further supports the notion that CENPF is essential for maintaining the rapid cell division characteristic of keloids. These results establish a clear regulatory axis where CD147 promotes keloid formation by modulating CENPF-mediated suppression of p53.

The identification of the CD147-CENPF signaling pathway offers a promising target for future therapeutic interventions. While the study provides compelling evidence for this mechanism in vitro, the authors acknowledge limitations, including the small sample size of human tissues and the lack of assessment for sex-related effects. Additionally, the role of other CD147 ligands, such as integrin β1 and caveolin-1, in keloid pathogenesis remains to be fully explored. The humanized anti-CD147 antibody meplazumab, which has been approved for the treatment of severe SARS-CoV-2 infection, may offer a complementary approach to small-molecule inhibitors like AC-73. Combination therapies targeting both membrane-bound and soluble forms of CD147 could potentially enhance the efficacy of keloid treatment.

In summary, this study elucidates a previously unrecognized mechanism by which CD147 drives keloid formation through the CENPF signaling pathway. By promoting fibroblast proliferation and suppressing apoptosis, this pathway contributes to the uncontrolled growth and persistence of keloids. Targeting this axis could lead to the development of more effective treatments for keloid patients, addressing the current unmet medical need for therapies that prevent recurrence and improve quality of life. Further clinical trials are required to validate these findings in humans, but the molecular insights gained from this research provide a strong foundation for the next generation of keloid therapies.

Subject of Research: Molecular mechanisms of keloid fibroblast proliferation via CD147 and CENPF signaling

Article Title: CD147 drives keloid formation by promoting fibroblast proliferation via the CENPF signaling pathway

Article References: Diao, J.-S., Han, X.-N., Du, H.-C., Wu, J., Jia, J., Zhang, Z., Rahman, M. A., & Shu, M.-G. (2026). CD147 drives keloid formation by promoting fibroblast proliferation via the CENPF signaling pathway. iScience, 29(11), Article 117927. https://doi.org/10.1016/j.isci.2026.117927

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117927

Keywords: keloids, CD147, CENPF, fibroblasts, cell cycle, p53 pathway, dermatology, signaling pathways, tissue repair, iScience, drives, keloid

The research team set out to understand how scirrhous gastric cancer cells and cancer-associated fibroblasts, or CAFs, communicate within the tumor microenvironment and how that communication drives progressive invasion. Using four pairs of CAFs and normal fibroblasts derived from patients, together with three gastric cancer cell lines, the investigators combined RNA sequencing with functional assays to identify molecular markers that distinguish the activated fibroblasts of the tumor stroma from their normal counterparts. Their in silico analysis pointed to stanniocalcin-1, a secreted glycoprotein previously implicated in tissue remodeling and stress responses, as a reliable marker of the cancer-associated fibroblast phenotype.

Laboratory measurements confirmed the significance of this finding. The mRNA expression of stanniocalcin-1 in CAFs was significantly higher than in normal fibroblasts, and, critically, the expression was significantly upregulated when the fibroblasts were exposed to the supernatant, or conditioned medium, of OCUM-12 cells, a scirrhous gastric cancer cell line. This observation demonstrated that something released by the aggressive cancer cells could reprogram the fibroblasts to produce more of this secreted protein, suggesting a directed molecular dialogue rather than random stromal activation.

Functional testing then revealed the consequences of this dialogue. Stanniocalcin-1 secreted by the CAFs was associated with increased invasion activity of the scirrhous gastric cancer cells and with the induction of epithelial-mesenchymal transition, the developmental program by which epithelial cancer cells lose their cell-cell adhesion properties and gain migratory, invasive characteristics. Morphologic analysis of the cancer cells exposed to CAF-conditioned medium showed the characteristic spindle-like shape changes of EMT, confirming that the fibroblast-derived signal was not merely a bystander effect but a driver of the invasive phenotype.

The investigators then turned their attention to what the cancer cells were contributing to this exchange. Their candidate was mesotrypsin, a trypsinogen isoform encoded by the PRSS3 gene, which is known to be expressed in aggressive pancreatic and other gastrointestinal malignancies. Mesotrypsin released from OCUM-12 cells was found to activate protease-activated receptor 2, or PAR-2, a cell surface receptor that responds to proteolytic cleavage by trypsin-like enzymes. When mesotrypsin cleaved PAR-2 on the surface of the fibroblasts, it triggered an intracellular signaling cascade through the signal transducer and activator of transcription 3, or STAT-3, pathway, which in turn upregulated stanniocalcin-1 expression in the CAFs.

What makes this discovery particularly striking is the reciprocal nature of the interaction. The investigators found that PRSS3/mesotrypsin expression in the cancer cells was itself upregulated by stanniocalcin-1, completing a positive feedback loop. Cancer cells secrete mesotrypsin, which activates PAR-2 on fibroblasts, which activates STAT-3, which increases stanniocalcin-1 production, which feeds back to the cancer cells to increase mesotrypsin expression, which then further stimulates the fibroblasts. Each round of this mutual amplification strengthens the invasive behavior of the cancer cells and deepens the activated state of the stromal fibroblasts, creating a self-reinforcing engine of tumor progression.

The clinical relevance of this circuit was underscored by survival analysis of gastric cancer patients. The investigators found that high mesotrypsin expression contributed to significantly poorer survival in gastric cancer patients, linking the molecular mechanism identified in vitro to patient outcomes. This finding suggests that mesotrypsin expression levels could serve as a prognostic biomarker, helping clinicians identify patients whose tumors have engaged this aggressive stromal interaction program and who may require more intensive treatment strategies.

From a therapeutic perspective, the identification of the PAR-2/STAT-3/stanniocalcin-1 axis in CAFs and the reciprocal PRSS3/mesotrypsin signal from cancer cells opens multiple potential intervention points. Blocking PAR-2 activation, inhibiting STAT-3 signaling, neutralizing stanniocalcin-1, or suppressing mesotrypsin activity could each disrupt the feedback loop at a different stage. Because the loop requires both partners to sustain itself, targeting either side could potentially collapse the entire mutual promotion circuit, offering a strategy that conventional chemotherapy directed solely at cancer cells cannot achieve.

The study also contributes to a broader shift in cancer research toward understanding the tumor microenvironment as an active participant in disease progression rather than a passive scaffold. Scirrhous gastric cancer, with its dense fibrotic stroma, represents an extreme example of this principle, where the stromal compartment is not merely abundant but functionally indispensable to the invasive phenotype. By demonstrating that cancer cells and fibroblasts engage in a specific, targetable molecular dialogue, the Osaka Metropolitan University team has provided a mechanistic framework that may explain why this subtype is so relentlessly invasive and has identified a promising direction for the development of stroma-directed therapies for one of the most challenging malignancies in oncology.

Subject of Research: PRSS3/mesotrypsin from scirrhous gastric cancer cells and stanniocalcin-1 from cancer-associated fibroblasts mutually promote invasion activity

Article Title: PRSS3/mesotrypsin from scirrhous gastric cancer cells and stanniocalcin-1 from cancer-associated fibroblasts mutually promote invasion activity

Article References: Sakuma, T., Gao, H., Ma, D., Sano, T., Imanishi, D., Fan, C., Nishikubo, H., Yamamoto, Y., Kasashima, H., Yashiro, M., & Maeda, K. (2026). PRSS3/mesotrypsin from scirrhous gastric cancer cells and stanniocalcin-1 from cancer-associated fibroblasts mutually promote invasion activity. BMC Cancer. https://doi.org/10.1186/s12885-026-16988-y

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16988-y

Keywords: PRSS3, mesotrypsin, scirrhous, gastric, cancer, cells, stanniocalcin-1, cancer-associated, fibroblasts, mutually, promote, invasion

The research team, led by Haonan Zhang, Yulu Shi and Qiuyu Song under the supervision of Mingsong Li at the Third Affiliated Hospital of Guangzhou Medical University, combined single-nuclei transcriptomics, spatial transcriptomics, ecological dynamic modelling, multiplex immunohistochemistry, in vitro co-culture experiments and in vivo animal studies. This comprehensive approach allowed them to track how individual cell subtypes change and interact as inflammatory bowel disease progresses toward cancer, addressing a gap that previous bulk and single-cell studies had left open, particularly because few investigations had been conducted at single-nuclei level.

At the centre of the finding are CXCL14+ fibroblasts, a subset of stromal cells defined by their production of the chemokine CXCL14. The analysis revealed that these fibroblasts are the primary source of collagen within the gut microenvironment and that their abundance increases progressively during the transition from inflammation to cancer. Crucially, they secrete elevated levels of collagen IV, encoded by the COL4A1 and COL4A2 genes. Collagen IV is best known as a structural component of basement membranes, but the new data show it acts as a signalling molecule that reshapes the immune landscape of the inflamed gut.

The technical pathway the researchers traced begins with the transcription factor SOX4. During the inflammation-cancer transition, activation of SOX4 in CXCL14+ fibroblasts leads to increased COL4A1/A2 secretion, enhancing collagen IV synthesis. The secreted collagen IV then binds to ITGB1 and CD44 receptors on the surface of SPP1+ macrophages, a subset of immune cells named for their production of the glycoprotein osteopontin, or SPP1. This binding activates the transcription factors EGR1 and EGR2, promoting differentiation of these macrophages while upregulating the proteins S100A10 and ANXA2.

Activation of S100A10 and ANXA2 promotes recruitment of SPP1+ macrophages into the tissue, and this influx contributes to immune escape and the secretion of oncogenic factors, further promoting fibrosis and tumorigenesis. The study also found that the ratio of CXCL9+ to SPP1+ macrophages decreases as IBD-related cancer progresses, a shift consistent with recent work in Science showing that CXCL9:SPP1 macrophage polarity identifies cellular programs that control human cancers. In the inflamed gut, the balance tips toward the SPP1+ state, which favours scarring and tumour growth rather than antitumour immunity.

Perhaps the most striking discovery is that the interaction is not one-directional. SPP1+ macrophages stimulate CXCL14+ fibroblasts to secrete more COL4A1/A2 via TGF-β1, forming a feedback loop that amplifies the crosstalk within the tumour microenvironment. Each cycle of this loop deposits more collagen, recruits more macrophages, and pushes the tissue further along the road from chronic inflammation to fibrosis and cancer. Ecological dynamic modelling showed that these interactions become more frequent in the CMS4 molecular subtype of colorectal cancer, which is characterised by a prominent stromal component.

The in vivo experiments provided direct causal evidence. CXCL14 and collagen IV promoted colitis-associated tumorigenesis in animal models, confirming that the fibroblast-macrophage axis is not merely a correlate of disease progression but an active driver of it. When the researchers inhibited collagen IV secretion, the results were twofold: the intervention not only prevented fibrosis but also hindered the development of the inflammation-cancer transition. This dual effect suggests that a single molecular target could address both of the major long-term complications of inflammatory bowel disease.

The therapeutic implications extend to a class of drugs already under development. Treatment with a discoidin domain receptor 1/2 inhibitor, which blocks collagen signalling receptors, restrained colitis-associated tumorigenesis in the animal studies. DDR1/2 inhibitors such as VU6015929 have been explored as antifibrotic agents in other contexts, and the new findings position them as candidates for preventing both stricture formation and malignancy in patients with long-standing inflammatory bowel disease. Because tumour-associated fibrosis is known to impair the response to immunotherapy, dismantling this stromal barrier could also improve the effectiveness of existing cancer treatments in patients who do develop IBD-associated malignancies.

The study addresses a clinically urgent problem. Population-based cohort studies with decades of follow-up have established that patients with inflammatory bowel disease face elevated risks of colorectal cancer, small bowel cancer and other gastrointestinal malignancies, and systematic reviews show that IBD-associated colorectal cancer carries distinct clinicopathological features and survival outcomes. Fibrosis leading to strictures is itself a risk factor for high-grade dysplasia and cancer in ulcerative colitis, and serological biomarkers of type I, III and IV collagen turnover have been associated with the presence and future progression of stricturing and penetrating Crohn’s disease. The new work provides a mechanistic framework that connects these epidemiological observations to specific cell types and signalling molecules.

By resolving the dynamics of cell subtypes at single-nuclei level and validating the findings through spatial mapping, co-culture and animal models, the researchers have identified CXCL14+ fibroblasts and their collagen IV secretion as a pivotal node in the inflammation-cancer transition. The identification of the SOX4-COL4A1/A2-ITGB1/CD44-EGR1/2-S100A10/ANXA2 pathway, together with the TGF-β1-mediated feedback loop, offers a detailed molecular map for developing innovative therapeutic strategies. The raw sequence data have been deposited in the Genome Sequence Archive under accession HRA009030, and the authors report no competing interests. The work was supported by the National Natural Science Funds of China and regional research funds from Guangdong and Guangzhou.

Subject of Research: Cellular and Molecular Biology

Article Title: CXCL14+ fibroblasts promote development of IBD-associated fibrosis and cancer by interacting with SPP1+ macrophages via collagen IV secretion

Article References: Zhang, H., Shi, Y., Song, Q., Li, N., Lin, Z., Chen, Q., Yang, Y., Chen, Y., Liu, Q., Tan, Y., Zheng, Y., Wang, S., Sun, Y., Li, X., He, C., Zhu, L., & Li, M. (2026). CXCL14+ fibroblasts promote development of IBD-associated fibrosis and cancer by interacting with SPP1+ macrophages via collagen IV secretion. British Journal of Cancer. https://doi.org/10.1038/s41416-026-03636-2

Image Credits: AI Generated

DOI: 10.1038/s41416-026-03636-2

Keywords: inflammatory bowel disease, colorectal cancer, fibrosis, cancer-associated fibroblasts, macrophages, collagen IV, single-nuclei transcriptomics, tumour microenvironment, DDR1/2 inhibitors, spatial transcriptomics, CXCL14, fibroblasts

The research, conducted by Klaudia Walczak and colleagues at the University of Gdańsk and published in the journal Acta Biochimica Polonica, examined fibroblasts — connective tissue cells grown in the laboratory — obtained from patients with eleven distinct mucopolysaccharidosis subtypes, ranging from the relatively common types I, II, and III to the rarer types IV, VI, VII, and IX. The team purchased these patient-derived cell lines from the Coriell Institute for Medical Research in New Jersey, alongside a control line of healthy fibroblasts, and grew them under standard laboratory conditions. The approach allowed the researchers to compare mitochondria across an unusually wide spectrum of the disease in a single, systematic analysis.

To visualize mitochondria, the team used a fluorescent dye called MitoTracker Green, which lights up these organelles under the microscope regardless of their functional state. Using this technique, the researchers measured two key parameters: the total area occupied by the mitochondrial network within each cell, and the number of discrete fluorescent objects — which the researchers interpreted as individual mitochondria — identified after computer-based image analysis. The results were surprisingly uniform. Across all eleven disease subtypes, neither the size of the mitochondrial network nor the apparent number of mitochondria differed significantly from the healthy control cells. In other words, at the level of structure, mitochondria in these patient cells looked essentially normal.

This structural normality was unexpected, because earlier studies using electron microscopy had reported changes in mitochondrial appearance in fibroblasts from patients with several mucopolysaccharidosis subtypes, including increases in mitochondrial number and alterations in mitochondrial shape. The discrepancy may reflect differences in technique. Electron microscopy can resolve individual organelles with far greater precision, while the fluorescence-based approach used in the new study relies on thresholding fluorescent objects after image segmentation — a process that may merge or split mitochondria in ways that do not perfectly reflect their true biology. The researchers themselves acknowledged this limitation, noting that the parameter they measured may not perfectly correspond to the actual number of isolated mitochondria within the cell.

But the study’s most interesting findings came not from the microscope but from the genetic analysis. The team extracted total DNA from each cell line and used a quantitative polymerase chain reaction technique to measure the relative abundance of mitochondrial DNA — the small circular genome housed within mitochondria — compared with nuclear DNA, using a gene called β-globin as the nuclear reference. This ratio, known as the mtDNA/nDNA ratio, is a widely used proxy for mitochondrial content within a cell, and changes in this ratio can signal alterations in mitochondrial biogenesis, the process by which cells build new mitochondria. The results were strikingly different from the structural findings.

In several disease subtypes, the mtDNA/nDNA ratio was significantly lower than in the healthy control cells. The most pronounced decreases appeared in types I, II, IIIA, and VI — a pattern that did not align neatly with the structural normality observed under the microscope. In the remaining disease subtypes, the ratio did not differ significantly from the control. This dissociation between structure and genetic content is biologically meaningful, because it suggests that in some mucopolysaccharidosis subtypes, mitochondria may be present in normal numbers and normal organization but may carry less mitochondrial DNA per cell — a change that could reflect alterations in mitochondrial biogenesis or in the copy number of the mitochondrial genome within individual organelles.

The researchers interpreted these findings cautiously, emphasizing that the study was designed to be exploratory rather than definitive. They noted that mtDNA copy number is known to vary widely among healthy individuals, and that the normal range for this parameter is broad enough that modest decreases may fall within the spectrum of healthy variation. They also acknowledged that the study used a single patient-derived cell line per disease subtype, which means that the observed changes could reflect donor-specific variability rather than disease-specific biology. Without replication across multiple patients per subtype, the findings cannot be definitively attributed to the disease itself.

Nevertheless, the pattern of decreased mtDNA content in specific subtypes — particularly types I, II, IIIA, and VI — is consistent with earlier reports of mitochondrial dysfunction in these diseases. Previous studies have documented reduced activity of the electron transport chain, the series of protein complexes that generates cellular energy, in fibroblasts and other cell types from patients with several mucopolysaccharidosis subtypes. Other work has reported increased production of reactive oxygen species, the damaging molecules generated as byproducts of mitochondrial energy production, and alterations in mitochondrial dynamics, the processes by which mitochondria fuse, divide, and move within the cell. The new study’s genetic findings add another layer to this accumulating evidence, suggesting that the mitochondrial genome itself may be altered in some disease subtypes.

The dissociation between structural normality and decreased mtDNA content also raises important questions about how mitochondria change in mucopolysaccharidoses. One possibility is that the diseases alter mitochondrial biogenesis — the process by which cells build new mitochondria — without changing the overall organization of the mitochondrial network. Another possibility is that the diseases reduce the copy number of the mitochondrial genome within individual organelles, a change that would be invisible to structural imaging but detectable by genetic analysis. Yet another possibility is that the observed decreases reflect a compensatory response, in which cells reduce mitochondrial content as a way of limiting the production of damaging reactive oxygen species. Distinguishing among these possibilities will require further study.

The researchers also emphasized the limitations of their cell model. Fibroblasts are readily accessible and easy to grow in the laboratory, making them a convenient model for studying rare diseases, but they may not fully recapitulate the biology of the tissues most affected by mucopolysaccharidoses, particularly the brain, skeleton, and heart. Skin fibroblasts from patients with these diseases do show some disease-related changes, including accumulation of glycosaminoglycans and alterations in gene expression, but the extent to which mitochondrial changes observed in fibroblasts reflect changes in other tissues remains uncertain. Future studies using neurons, cartilage cells, or heart muscle cells — or induced pluripotent stem cell-derived models of these tissues — may provide a more complete picture of mitochondrial involvement in the disease.

Despite these limitations, the study represents one of the broadest systematic analyses of mitochondria across the mucopolysaccharidosis spectrum, and its findings add important nuance to the ongoing debate about mitochondrial involvement in these rare diseases. The structural normality observed under the microscope suggests that mitochondria in these patient cells are not grossly disorganized, while the decreased mtDNA content in specific subtypes suggests that more subtle changes may be occurring at the level of the mitochondrial genome. The dissociation between these two levels of analysis highlights the importance of combining structural and genetic approaches in future studies of mitochondrial biology in rare diseases.

The findings also underscore the value of exploratory research in rare diseases. Mucopolysaccharidoses affect a small number of patients worldwide, and the rarity of these conditions makes large-scale clinical studies difficult to conduct. Laboratory-based analyses of patient-derived cells, such as the one conducted by the Polish team, offer a practical way to generate hypotheses about disease biology that can later be tested in more targeted studies. The new study’s findings — structural normality combined with decreased mtDNA content in specific subtypes — provide exactly this kind of hypothesis-generating evidence, pointing the way toward future research that may clarify the role of mitochondria in the pathology of these devastating conditions.

As the field moves forward, the challenge will be to integrate these exploratory findings with the accumulating evidence of mitochondrial dysfunction in mucopolysaccharidoses and to determine whether the observed changes are causes or consequences of the disease process. The new study’s cautious, hypothesis-generating approach reflects the reality of research in rare diseases, where definitive answers are hard to come by and progress often depends on the patient accumulation of suggestive evidence. For now, the Polish team’s findings add an important piece to the puzzle, suggesting that mitochondria in mucopolysaccharidoses may be more subtly altered than previously thought — and that the mitochondrial genome, rather than the organelle’s structure, may hold the key to understanding their involvement in these rare conditions.

Subject of Research: Mitochondrial morphology and mtDNA content in fibroblasts from patients with different types of mucopolysaccharidosis

Article Title: Mitochondrial morphology and mtDNA content in fibroblasts from patients with different types of mucopolysaccharidosis

Article References: Walczak, K., Gaffke, L., Pierzynowska, K., Sowa-Rogozińska, N., & Piotrowska, E. (2026). Mitochondrial morphology and mtDNA content in fibroblasts from patients with different types of mucopolysaccharidosis. Acta Biochimica Polonica, 73, Article 16345. https://doi.org/10.3389/abp.2026.16345

Image Credits: AI Generated

DOI: 10.3389/abp.2026.16345

Keywords: Mitochondrial, morphology, mtDNA, content, fibroblasts, patients, different, types, mucopolysaccharidosis, scientific research

Oculodentodigital dysplasia, or ODDD, is an ultra-rare autosomal dominant disorder caused by germline variants in GJA1. Patients typically show a pleiotropic constellation of features affecting the eyes, teeth, digits, and sometimes the central nervous system, with severity varying dramatically even within the same family. Connexin 43 is the most ubiquitously expressed connexin in the human body, forming gap junction channels that allow direct cytoplasmic exchange between adjacent cells. But the protein’s long C-terminal tail also does channel-independent work, physically associating with signaling partners such as β-catenin and various kinases. It is this second, scaffolding role that the new research places at the center of the disease mechanism.

The team, led by researchers at Peking Union Medical College Hospital and Children’s Hospital of Soochow University, recruited two families with classic ODDD presentations. Proband 1, a young girl, displayed short palpebral fissures, hypoplastic alae nasi, sparse hair, bilateral syndactyly of the fourth and fifth fingers, and dental anomalies including microdontia and enamel hypoplasia. Her affected younger brother carried the same craniofacial and hand phenotype, while their mother showed only mild bilateral brachydactyly of the fifth fingers—a striking example of intra-familial variability. Proband 2 presented similar features along with syndactyly of the toes, and whole-genome sequencing revealed his variant arose de novo, absent from both clinically healthy parents. Sanger sequencing confirmed heterozygous missense variants, c.253G>C in Family 1 and c.605G>A in Family 2, both segregating perfectly with disease status.

What makes the study unusual is its reliance on primary patient-derived cells rather than engineered model systems. The researchers cultured skin fibroblasts from both patients and mesenchymal stromal cells, or MSCs, harvested from discarded surgical bone and skin tissue collected during syndactyly release and corrective osteotomy procedures. Controls came from age- and sex-matched pediatric patients undergoing hand trauma surgery at the same anatomical site, with whole-genome sequencing used to exclude any pathogenic variants in known disease genes. Flow cytometry confirmed the MSC identity, with cells positive for CD90, CD105, and CD73 and negative for CD45, meeting the International Society for Cellular Therapy minimal criteria.

RNA sequencing on patient fibroblasts and MSCs revealed a transcriptional landscape split cleanly in two. Downregulated gene sets were dominated by Wnt signaling, extracellular matrix–receptor interaction, osteoblast differentiation, DNA replication, and cell cycle regulation. Upregulated sets lit up with inflammatory response genes, cytokine-mediated signaling, JAK-STAT signaling, tumor necrosis factor response, and ECM structural constituents. The team then validated these patterns at the protein level using RT-qPCR, Western blotting, immunofluorescence, and ELISA. In both fibroblasts and MSCs, mRNA levels of canonical Wnt targets—AXIN2, CCND1, PCNA, and c-MYC—fell sharply. Protein levels of Cx43, β-catenin, and IκBα dropped in parallel, while the ratio of phosphorylated p65 to total p65 rose, a signature of NF-κB pathway activation.

The inflammatory profile that emerged is the study’s most surprising finding. Interleukin-6 expression and secretion surged in patient cells, yet CXCL8—better known as IL-8—was paradoxically and significantly reduced, despite NF-κB being switched on. Interferon-stimulated genes MX1 and IFIT1 were simultaneously elevated. The researchers traced this uncoupling to c-MYC, the Wnt-dependent transcription factor whose loss appears to lift normal repression on MMP3 while simultaneously starving CXCL8 of a required activator. MMP3, or stromelysin-1, is a matrix metalloproteinase that degrades components of the extracellular matrix, and its abnormal upregulation points to excessive ECM remodeling—a process that could plausibly underlie the tissue fusion seen in syndactyly, though the authors caution that this connection remains speculative and requires in vivo validation.

Functional assays confirmed the molecular story has real cellular consequences. Transwell migration assays showed patient fibroblasts and MSCs crossed basement membranes at markedly reduced rates, while EdU incorporation revealed suppressed proliferation. These defects align with the coordinated downregulation of CCND1, PCNA, and c-MYC, key regulators of the G1/S cell cycle transition, suggesting GJA1 deficiency stalls cells before they enter DNA synthesis. Differentiation assays added another layer: patient MSCs showed compromised osteogenic capacity, with reduced alkaline phosphatase activity and diminished Alizarin Red S mineralization, alongside aberrantly enhanced adipogenic potential measured by Oil Red O staining. This lineage shift mirrors the classical biology of Wnt signaling, which normally maintains MSC stemness, promotes bone formation, and suppresses fat cell differentiation—offering a cellular explanation for the bone hypoplasia seen in ODDD patients.

To establish causality rather than mere correlation, the team ran bidirectional genetic interventions. Knocking down GJA1 with siRNA in normal control cells, reducing expression to roughly the level seen in patient cells, faithfully reproduced the entire patient phenotype: Wnt suppression, the IL-6-high/CXCL8-low inflammatory bias, elevated MMP3, impaired migration, and skewed differentiation. Conversely, overexpressing wild-type connexin 43 in patient cells substantially reversed these defects, restoring IκBα levels, reducing p65 phosphorylation, suppressing MMP3, and rescuing migration. A second round of experiments isolated c-MYC’s role directly: silencing c-MYC in normal MSCs reproduced the CXCL8 collapse and MMP3 surge, while overexpressing c-MYC in patient MSCs rescued both, establishing c-MYC as a necessary and sufficient regulator of these two genes downstream of the GJA1/Wnt axis.

Pharmacological experiments then mapped the hierarchy of the pathway. Treating patient cells with CHIR99021, a selective GSK-3β inhibitor that activates canonical Wnt signaling, restored c-MYC expression, corrected the CXCL8 deficit, suppressed MMP3, reduced IL-6 secretion, and improved both migration and osteogenic differentiation. In contrast, a neutralizing antibody against IL-6 acted only on downstream readouts: it dampened the interferon response but failed to restore c-MYC, could not rescue CXCL8, and left MMP3 overexpression untouched. The combination of both agents produced the strongest overall rescue, simultaneously targeting the core upstream defect and the downstream inflammatory overactivation. The comparison makes a clear translational argument: blocking a single cytokine treats symptoms, but reactivating the Wnt/c-MYC axis addresses the disease’s root signaling failure.

The authors are candid about the study’s limits. Fibroblasts came from only two patients and MSCs from one, so transcriptomic findings are explicitly framed as exploratory, and technical replicates from a single donor cannot substitute for independent biological replicates. The researchers also could not perform promoter-reporter or chromatin immunoprecipitation experiments to demonstrate direct c-MYC binding at the CXCL8 or MMP3 promoters, again because of the scarcity of pediatric patient cells. Connexin 43’s broad expression in heart, brain, and skin means long-term neurological and cardiac follow-up of the two families is warranted, even though neither child currently shows overt deficits in those systems. Still, the work delivers a coherent new pathogenic framework for ODDD—one in which a broken gap junction protein silently rewires Wnt, NF-κB, and matrix remodeling all at once—and it nominates Wnt activation, rather than isolated cytokine blockade, as the therapeutic strategy most worth pursuing in this rare and poorly understood disorder.

Subject of Research: Molecular mechanisms of GJA1-related oculodentodigital dysplasia in patient-derived fibroblasts and mesenchymal stromal cells

Article Title: GJA1 dysfunction suppresses Wnt/c-MYC signaling and promotes inflammatory imbalance and MMP3-associated ECM remodeling in fibroblasts and mesenchymal stromal cells from patients with ODDD

Article References: Tao, S., Zhao, B., Wang, X., Shen, X., & Zhao, X. (2026). GJA1 dysfunction suppresses Wnt/c-MYC signaling and promotes inflammatory imbalance and MMP3-associated ECM remodeling in fibroblasts and mesenchymal stromal cells from patients with ODDD. Frontiers in Cell and Developmental Biology, 14, Article 1959966. https://doi.org/10.3389/fcell.2026.1959966

Image Credits: AI Generated

DOI: 10.3389/fcell.2026.1959966

Keywords: oculodentodigital dysplasia, GJA1, connexin 43, Wnt signaling, c-MYC, NF-κB, MMP3, mesenchymal stromal cells, fibroblasts, rare disease, osteogenic differentiation, CHIR99021

The new study, published in Nature Communications by a team led by Yuichi Oike and Michio Sato of Kumamoto University together with colleagues across Japan and at Bristol Myers Squibb, began with an epidemiological observation that has often been overlooked. In three separate Japanese HFpEF cohorts, the dominant clinical features were not obesity, which is common in European and North American HFpEF populations, but hypertension and overactivation of the sympathetic nervous system, the branch of the autonomic nervous system that drives the fight-or-flight response. This distinction matters because most experimental models of HFpEF have been built around obesity and metabolic syndrome, potentially missing the biology that drives the disease in a large share of patients worldwide.

To capture that non-obese phenotype, the researchers engineered a mouse model in which two insults converge. First, sympathetic activation induces hypertensive heart disease, subjecting the heart to chronic pressure overload. Second, endothelial dysfunction, a impairment of the blood vessel lining that normally helps regulate vascular tone and tissue perfusion, acts as a second hit that pushes the stressed heart across the threshold into full HFpEF. Only when both factors were present did the animals develop the characteristic signature of the human syndrome: the heart stiffens, filling pressures rise, and exercise capacity collapses, all while the pumping fraction remains preserved.

With a faithful model in hand, the team turned to the heart’s resident immune cells. Macrophages, the versatile white blood cells that patrol tissues and coordinate inflammation, have increasingly been recognized as active participants in cardiac remodeling rather than passive bystanders. Using single-cell transcriptomics and intercellular signaling analysis, the investigators found that hypertensive stress fundamentally rewires the communication network that cardiac macrophages maintain with their neighbors. The rewiring was not subtle. It reoriented the entire signaling economy of the heart toward two opposing but equally damaging outcomes.

On one side of the ledger, macrophage-to-cardiomyocyte signaling through the bone morphogenetic protein, or BMP, pathway was markedly impaired. BMP signaling in heart muscle cells supports fatty acid oxidation, the metabolic process by which cardiomyocytes burn fat as their preferred fuel. When macrophages stop delivering this signal, the heart muscle cells shift away from efficient fat metabolism, a metabolic remodeling that starves the working myocardium of energy and promotes dysfunction. On the other side, macrophage-to-fibroblast signaling through platelet-derived growth factor, or PDGF, was enhanced. Fibroblasts are the scar-forming cells of the heart, and amplified PDGF signaling drove them into a proliferative, fibrosis-producing state, stiffening the cardiac tissue further and worsening diastolic function.

The linchpin connecting these two arms of the rewired network turned out to be a secreted protein called angiopoietin-like protein 2, or ANGPTL2. This molecule, which the group had previously studied in the context of chronic inflammation and vascular biology, was upregulated in cardiac macrophages under hypertensive stress and appeared to orchestrate the pathological shift in intercellular communication. When the researchers inhibited ANGPTL2, using a neutralizing antibody developed in collaboration with Bristol Myers Squibb, the macrophage signaling network was largely preserved. The metabolic collapse in cardiomyocytes was blunted, fibroblast activation was restrained, inflammation and fibrosis were reduced, and, critically, the animals were protected from developing HFpEF.

These findings carry several layers of significance. Scientifically, they elevate cardiac macrophage signaling from a correlate of heart failure to a central causal mechanism, positioning a single immune-derived node as the link between mechanical stress, metabolic remodeling, inflammation, and fibrosis. Clinically, they suggest that HFpEF is not one disease but at least two, with an obesity-driven form on one side and a hypertension-and-sympathetic-activation-driven form on the other. If the macrophage rewiring described here proves to operate specifically in the non-obese variant, therapies targeting ANGPTL2 could offer a precision approach that current broad-spectrum HFpEF trials have lacked.

The translational path is plausible but not guaranteed. The work was performed in mice, and human HFpEF is notoriously heterogeneous, shaped by age, sex, comorbidities, and environment in ways that animal models only approximate. The researchers themselves note that their model was designed to reproduce the Japanese clinical picture, and whether the same macrophage signaling rewiring operates in obese HFpEF patients in Western cohorts remains an open question. Still, the existence of a validated neutralizing antibody against ANGPTL2, developed with an industry partner, means that the pharmacological tools needed to test the hypothesis in patients already exist, which is far from typical for early mechanistic discoveries.

For the millions of people living with HFpEF, many of them older adults with long-standing hypertension and no obesity at all, the study offers something the field has lacked for decades: a molecular explanation rooted in the immune system for why their hearts stiffen and fail despite a preserved pumping fraction. It also reframes the macrophage not merely as a source of inflammation but as a metabolic regulator of the heart, one whose signals can either sustain or sabotage the energy metabolism of the muscle it surrounds. If subsequent studies confirm that blocking ANGPTL2 preserves macrophage communication in humans as it does in mice, the discovery could mark the beginning of the first mechanism-targeted therapy for a form of heart failure that has resisted every treatment attempt so far.

Subject of Research: How hypertensive stress rewires cardiac macrophage signaling to drive heart failure with preserved ejection fraction independent of obesity

Article Title: Hypertensive stress rewires macrophage signaling in heart failure with preserved ejection fraction independent of obesity

Article References: Kinoshita, Y., Sato, M., Kadomatsu, T., Katoh, M., Ikeda, K., Yoshioka, G., Matsue, Y., Fujimoto, W., Kurabayashi, A., Okadome, Y., Torigoe, D., Wakayama, T., Horiguchi, H., Kusaba, R., Peiwen, X., Gurbuzbalaban, B. E., Rakestraw, G., Yamniuk, A., Pipes, G. T., … Oike, Y. (2026). Hypertensive stress rewires macrophage signaling in heart failure with preserved ejection fraction independent of obesity. Nature Communications. https://doi.org/10.1038/s41467-026-78375-2

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78375-2

Keywords: heart failure, HFpEF, macrophages, hypertension, ANGPTL2, fibrosis, metabolic remodeling, cardiomyocytes, fibroblasts, endothelial dysfunction, sympathetic activation, Nature Communications

The core problem with diabetic foot ulcers is that they are not single diseases. They arise from a convergence of peripheral neuropathy, ischemia and hypoxia, and recurrent infection, all superimposed on a metabolic environment warped by chronic hyperglycemia. Sensory neuropathy strips patients of the protective pain reflexes that warn of minor trauma, while motor neuropathy deforms the foot and redistributes pressure onto vulnerable tissue. Autonomic dysfunction dries the skin, cracking the protective barrier and inviting bacterial entry. Meanwhile, prolonged high blood sugar drives atherosclerosis in the large vessels of the leg and damages the microcirculation, starving tissue of oxygen and nutrients. The result is a wound microenvironment in which matrix metalloproteinases run rampant, collagen synthesis lags, advanced glycation end products accumulate, and inflammation refuses to resolve. Conventional diagnostic tools, from the Ankle-Brachial Index to MRI and transcutaneous oxygen pressure measurement, capture the macroscopic consequences of this cascade but say little about the cellular actors driving it.

This is where single-cell RNA sequencing enters the picture. Unlike bulk transcriptomic methods, which measure average gene expression across thousands of mixed cells and thereby mask the contributions of rare subpopulations, scRNA-seq profiles each cell individually. The review’s authors explain that this resolution allows researchers to identify distinct cellular subtypes, map ligand-receptor interactions between cell populations using computational tools such as CellChat and iCELLNET, and reconstruct the pathological evolution of a wound at unprecedented depth. When integrated with spatial transcriptomics, which preserves the physical location of cells within tissue, and proteomics, which validates transcriptomic predictions at the protein level, the approach yields a multidimensional picture that bulk sequencing simply cannot match. The technology has already proven its worth in oncology, where it uncovered exhausted CD8-positive T cell signatures in hepatocellular carcinoma and identified macrophages and dendritic cells as key mediators in colorectal cancer, insights that have guided immunotherapy development.

Applied to diabetic foot ulcers, single-cell sequencing has produced its most striking findings in the immune compartment. Macrophages, the versatile scavengers and regulators of tissue repair, emerge as central players whose behavior is fundamentally corrupted in the diabetic wound. In healthy healing, pro-inflammatory macrophages dominate early to fight infection and clear debris, then give way to pro-resolving counterparts that secrete anti-inflammatory mediators such as C1QA, C1QB, C1QC and CD163, promoting tissue remodeling and angiogenesis. In diabetic wounds, this transition stalls. The review highlights that the histone demethylase JMJD3, an epigenetic regulator, activates the JAK1/3-STAT3 signaling axis and amplifies NF-kappa-B-mediated release of inflammatory cytokines including tumor necrosis factor and interleukins, effectively trapping macrophages in a pro-inflammatory state. Inhibition of JMJD3 in macrophages has been shown to alleviate inflammation and improve wound repair in both streptozotocin-induced type 1 and db/db type 2 diabetic mouse models, positioning the enzyme as a promising immunomodulatory target.

Beyond macrophages, single-cell atlases have exposed the heterogeneity of T lymphocytes in diabetic foot ulcers. Vu and colleagues found marked increases in naive T cells and CD8-positive T cells, resolving them into ten and seven distinct subclusters respectively. Cheng and colleagues reported upregulation of IL-17 signaling genes in CD8-positive T cells, alongside reduced expression of regulatory genes such as TSC22D3 and PIK3IP1, driving excessive activation and local inflammation. Regulatory T cells, which normally suppress inflammation through IL-10 and TGF-beta secretion, are significantly depleted in diabetic ulcers compared with normal wounds, weakening a critical brake on Th1 and Th17-driven immune responses. Natural killer T cells and gamma-delta T cells are enriched, contributing to a self-reinforcing cycle of infection, inflammation and impaired repair. Neutrophils, too, display remarkable diversity, with Retnlg-positive, Lcn2-positive, Wfdc21-positive and Mmp8-positive subsets identified, some of which peak during early ulcer formation and decline during healing, suggesting distinct roles in initiating versus resolving inflammation.

The stromal side of the wound tells an equally compelling story. Fibroblasts, the workhorses of extracellular matrix production and wound contraction, exhibit profound heterogeneity in diabetic ulcers. Buechler and colleagues generated a single-cell fibroblast atlas classifying lineages into general steady-state cells, specialized steady-state cells, and disturbance-specific activated cells. Januszyk and colleagues compared fibroblasts from diabetic and non-diabetic ulcers across ethnic groups, uncovering subpopulations with varied fibrotic potentials. A key mechanistic discovery came from Ku and colleagues, who showed that dysregulation of the IGF-1-SP1-CD248 pathway impairs fibroblast migration and delays healing. Healing-associated fibroblasts characterized by high expression of MMP1, MMP3, MMP11, HIF1A, CHI3L1 and TNFAIP6 concentrate in the central granulation bed, where they drive matrix remodeling and angiogenesis. Senescent, pro-inflammatory fibroblasts accumulate at the wound margin and avascular base, sustaining chronic inflammation and blocking closure. Spatial transcriptomics confirms that this dysfunctional spatial distribution, rather than transcriptional change alone, is a core determinant of refractory ulcer progression.

Vascular endothelial cells fare no better. Single-cell profiling of the public dataset GSE165816 revealed that core genes including CCND1, ENO1, HIF1A and SERPINE1 are significantly downregulated in endothelial cells of diabetic foot ulcers, undermining cell cycle regulation, hypoxic response and microcirculatory homeostasis. Two characteristic subsets emerge: functionally reparative endothelial cells marked by SLCO2A1 and CYP1A1, which are enriched in granulation tissue with healing potential, and senescent dysfunctional cells that predominate in refractory wounds, secreting anti-angiogenic factors such as thrombospondin-1 and pigment epithelium-derived factor. Hyperglycemia and hypoxia jointly suppress the Nrf2 antioxidant pathway while persistent NF-kappa-B activation floods the wound with pro-inflammatory mediators, creating a vicious cycle of endothelial injury, ischemia and senescence. Even keratinocytes are implicated, with quiescent BC-2 subsets failing to support re-epithelialization and senescent epidermal cells expressing p16INK4a and p21Cip1 losing proliferative and migratory capacity.

Perhaps most surprisingly, the review highlights the role of sensory neurons in coordinating repair. Lu and colleagues demonstrated that nociceptive neurons expressing calcitonin gene-related peptide engage RAMP1 receptors on neutrophils, monocytes and macrophages, reducing immune cell recruitment, accelerating apoptosis, enhancing phagocytosis and polarizing macrophages toward pro-resolving phenotypes. Loss of NaV1.8-positive sensory neurons impairs skin closure and muscle regeneration, providing a cellular-level explanation for why neuropathy and poor healing are so tightly linked. This neuroimmune axis, invisible to conventional bulk analyses, exemplifies the kind of mechanistic insight that single-cell approaches are uniquely positioned to deliver.

The translational implications are substantial. The review identifies MMP1, MMP3, MMP11, JMJD3 and HIF1A as valuable biomarkers and therapeutic targets, validated across multiple independent human cohorts and animal models. Computational drug-target network analysis has yielded seven potential core therapeutic targets and twenty candidate small-molecule drugs with translational potential. Single-cell signatures may eventually allow diabetic foot ulcers to be classified into inflammation-dominant, angiogenesis-deficient and matrix repair-impaired molecular subtypes, guiding individualized anti-inflammatory, pro-angiogenic or matrix-remodeling strategies. Yet significant barriers remain. Most studies rely on small, cross-sectional samples; db/db and streptozotocin mouse models cannot fully replicate the neuropathy, arterial occlusion and mixed infections characteristic of human disease; and sequencing costs, lack of standardized pipelines and insufficient prospective validation continue to limit clinical adoption. The authors argue that future progress will require stratified, longitudinal human cohorts, multi-omics integration combining spatial transcriptomics, proteomics and epigenomics, and rigorous preclinical validation of targets such as JMJD3 and STING. If those challenges can be met, single-cell technology may finally convert one of diabetes’ most intractable complications from a clinical guessing game into a data-driven precision discipline.

Subject of Research: Application of single-cell RNA sequencing to diabetic foot ulcer pathogenesis, biomarker discovery and translational research

Article Title: Single-cell RNA sequencing in diabetic foot ulcers: pathogenesis, biomarkers, and translational potential

Article References: Yang, S., Wang, S., Yang, R., Xu, K., Yang, X., & Zhao, Y. (2026). Single-cell RNA sequencing in diabetic foot ulcers: pathogenesis, biomarkers, and translational potential. Frontiers in Clinical Diabetes and Healthcare, 7, Article 1833678. https://doi.org/10.3389/fcdhc.2026.1833678

Image Credits: AI Generated

DOI: 10.3389/fcdhc.2026.1833678

Keywords: diabetic foot ulcer, single-cell RNA sequencing, macrophage polarization, wound healing, JMJD3, biomarkers, angiogenesis, fibroblasts, spatial transcriptomics, precision medicine, diabetes complications, IGF-1-SP1-CD248 pathway

The research, led by Caroline M. Haney and Elise T. Courtois, with Danielle E. Luciano and colleagues, tackles a problem that has hampered endometriosis research for decades. Endometriosis occurs when tissue resembling the uterine lining grows outside the uterus, most commonly on the ovaries and the peritoneum, the membrane lining the abdominal cavity. These lesions behave like small, inflamed organs in their own right, complete with glandular epithelium, supporting stromal cells, immune infiltrates and, as this study emphasizes, nerve fibers. Traditional bulk sequencing methods average out the signals from all of these cell types, obscuring the local interactions that likely drive symptoms.

Spatial transcriptomics changes that calculus fundamentally. Rather than dissociating tissue into a soup of single cells, the technology measures gene expression directly in intact tissue sections, preserving the geographic relationships between cells. In this study, the team applied high-resolution spatial profiling to human ovarian and peritoneal endometriosis specimens, effectively producing a molecular cartography of each lesion. Every cell’s identity and gene expression profile could be located within the tissue landscape, allowing the researchers to ask not just which cells are present, but which cells sit next to which, and what signaling molecules they exchange at those interfaces.

The resulting maps revealed striking commonalities between lesion types that are often treated as clinically distinct. Both ovarian and peritoneal lesions showed immune cell infiltration, organized fibroblast compartments encircling the epithelial glands, and characteristic distributions of neuronal and macrophage subsets. This shared spatial blueprint suggests that despite their different locations, the two most common lesion types may operate through convergent biological mechanisms, a finding with real implications for how therapies are designed and tested. A drug targeting a pathway common to both lesion environments could plausibly benefit patients regardless of where their disease manifests.

One of the most consequential contributions of the study is its precise definition of the sensory neuronal subtypes present within lesions and the mapping of their positions relative to immune cells. Pain in endometriosis is the dominant clinical complaint, yet the neural wiring of lesions has been difficult to study in human tissue. By identifying which classes of sensory neurons innervate the lesions and demonstrating that they occupy defined spatial relationships with macrophages and other immune populations, the researchers have built a structural case for neuroimmune crosstalk as a driver of endometriosis-associated pain. Macrophages, the tissue-resident immune cells capable of releasing inflammatory mediators and growth factors, are known to modulate nerve sensitivity in other chronic pain conditions, and the spatial proximity documented here suggests a similar dynamic may be at work in endometriotic tissue.

The fibroblast findings may prove equally important. Fibroblasts, the connective tissue cells that form the stromal scaffold of organs, were found to form distinct compartments surrounding the epithelial glands within lesions. In many fibrotic and inflammatory diseases, activated fibroblasts secrete cytokines, extracellular matrix components and growth factors that reshape the local environment and sustain chronic inflammation. The observation that these cells organize into periglandular niches in endometriosis lesions, conserved across lesion types, suggests they may be active participants in lesion maintenance rather than passive structural support, potentially creating the microenvironment in which epithelial cells, immune cells and nerves interact.

Crucially, the team did not stop at descriptive mapping. To test whether the epithelial-neuronal interactions inferred from the tissue sections are real, functional relationships, they built an in vitro model combining 3D peripheral sensory brain organoids with human endometriosis epithelial and fibroblast cells. Organoids are lab-grown, three-dimensional tissue cultures that recapitulate key features of the organ or tissue they model; sensory organoids derived from human induced pluripotent stem cells can generate neurons with the properties of peripheral sensory nerves. By co-culturing these neural structures with endometriosis-derived epithelial and stromal cells, the researchers could validate the interactome, the network of signaling interactions, that their spatial maps had predicted, providing experimental support that the epithelial-neuronal communication observed in patient tissue is biologically meaningful.

The technical achievement underlying these results should not be understated. The study drew on the EndoRISE Biorepository, part of the Connecticut Endometriosis Tissue and Data Biorepository funded by the State of Connecticut and The Mayday Fund, which supplied the patient biospecimens essential for such high-resolution work. The analysis leveraged The Jackson Laboratory’s Single Cell Biology Lab, Genome Technologies, Histology and Microscopy cores, along with high-performance computing resources, and used induced pluripotent stem cell lines from the laboratory’s Genetic Discovery initiative for the organoid work. Studies of this scale depend on patients consenting to donate tissue during surgery, and the authors specifically credit the study participants and the surgical teams at UConn Health who made the specimen collection possible.

What makes the study resonate beyond the technical community is what it implies for patients. Current endometriosis treatment options, hormonal suppression and surgical excision, address symptoms or remove visible disease but do not target the specific cellular mechanisms that generate pain and drive progression, and recurrence after surgery is common. A spatially resolved, mechanistic understanding of the lesion microenvironment gives drug developers concrete targets: the signaling pathways between sensory neurons and macrophages, the fibroblast niches around epithelial glands, and the conserved features shared across lesion types. Neuroimmune interactions in particular have emerged as a promising frontier in chronic pain research more broadly, and this study provides disease-specific, human-tissue evidence for pursuing that frontier in endometriosis.

There are, of course, limits to what any single atlas can establish. The study maps two lesion types, ovarian and peritoneal, and the authors frame their work as establishing the spatial transcriptomic cartography of those lesions rather than a complete account of all endometriosis presentations, such as deeply infiltrating disease. The organoid co-culture system validates epithelial-neuronal interactions in vitro but remains a simplified model of a complex in vivo environment. Still, the combination of high-resolution human tissue mapping with functional validation represents a methodological template that other chronic inflammatory diseases could follow. For a condition that has historically been underfunded, under-researched and frequently dismissed, the appearance of a rigorous, open-access, spatially resolved molecular atlas of endometriosis lesions marks a genuine step forward, one that transforms the disease from an opaque clinical syndrome into a mappable biological landscape with identifiable cellular players and testable therapeutic targets.

Subject of Research: Spatial transcriptomic mapping of fibroblast and neuroimmune microenvironments in human endometriosis lesions

Article Title: High-resolution spatial transcriptomics reveals fibroblast and neuroimmune microenvironments in endometriosis lesions

Article References: Haney, C. M., Alizadeh, E., Lee, J., Sullivan, M., Kuljancic, J., Flynn, W. F., Robson, P., White, B. S., Luciano, D. E., & Courtois, E. T. (2026). High-resolution spatial transcriptomics reveals fibroblast and neuroimmune microenvironments in endometriosis lesions. Nature Communications. https://doi.org/10.1038/s41467-026-78453-5

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78453-5

Keywords: endometriosis, spatial transcriptomics, fibroblasts, sensory neurons, macrophages, neuroimmune interactions, chronic pain, organoids, ovarian lesions, peritoneal lesions, single-cell biology, Nature Communications