The work builds on a decade of genetic evidence. Genome-wide association studies have repeatedly linked variants near the desmoplakin gene, DSP, to susceptibility to idiopathic pulmonary fibrosis, and independent work has shown that a functional variant, rs2076295, regulates desmoplakin expression in airway epithelial cells. Desmoplakin variants have also been associated with a distinctly fibrotic and inflammatory form of heart muscle disease, suggesting that this protein does more than glue cells together. What has been missing, however, is a mechanistic account of how reduced desmoplakin in the alveolar epithelium could translate into the collagen deposition, matrix stiffening, and epithelial dysfunction that define pulmonary fibrosis. The new study, led by first author Pooja Singh with senior author Ritushree Kukreti, sets out to close that gap.

To do so, the researchers used small interfering RNA to silence DSP expression in A549 cells, an adenocarcinoma-derived human alveolar epithelial cell line that is a workhorse of pulmonary fibrosis modeling. The consequences of losing desmoplakin were immediate and multifaceted. The cells underwent hallmarks of epithelial-to-mesenchymal transition, the process by which epithelial cells shed their polarized, adhesive identity and acquire migratory, matrix-producing characteristics. Cell migration increased, epithelial permeability rose, and the expression of fibrotic and extracellular matrix-associated genes climbed. Among the genes upregulated were COL1A1, which encodes the alpha-1 chain of type I collagen, the dominant structural protein of fibrotic scars, and MMP9, a matrix metalloproteinase that degrades and reshapes the extracellular matrix. In fibrotic lungs, the balance between matrix-degrading enzymes and their inhibitors is famously disrupted, and the appearance of these genes after DSP loss places desmoplakin squarely upstream of matrix remodeling.

To identify the pathway responsible, the team turned to the STRING database and mapped the known interaction partners of desmoplakin, then performed pathway enrichment analysis on that network. One signal rose above the rest: the canonical Wnt/β-catenin pathway, an ancient developmental signaling cascade whose reactivation in adult tissues is a well-documented feature of idiopathic pulmonary fibrosis. Prior studies have shown that functional Wnt signaling is increased in fibrotic human lungs and that β-catenin–dependent transcription supports the survival and migration of alveolar epithelial cells after injury. The enrichment analysis suggested that desmoplakin might act as a brake on this program—and that removing the brake would allow fibrotic signaling to run unchecked.

The mechanistic validation that followed is where the study becomes technically interesting. Desmosomes are not merely mechanical fasteners; their component proteins participate in signaling crosstalk, most notably through plakoglobin, also known as γ-catenin. Plakoglobin is a close molecular relative of β-catenin: both are armadillo-family proteins that compete for overlapping binding sites at junctions, and both can, in principle, enter the nucleus and engage T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factors. Crucially, plakoglobin acts as a transcriptional antagonist of β-catenin in several tissues. Landmark work in cardiomyocytes showed that nuclear plakoglobin suppresses canonical Wnt/β-catenin signaling, and that its loss underlies the pathology of arrhythmogenic cardiomyopathy. The New Delhi team hypothesized that an analogous arrangement governs the alveolar epithelium.

The experiments supported that hypothesis. Using cycloheximide chase assays, which block new protein synthesis and allow researchers to follow the decay of existing proteins over time, the researchers found that loss of desmoplakin destabilized desmosomal complexes and accelerated the degradation of plakoglobin. At the same time, β-catenin turnover was reduced, meaning the signaling-competent catenin persisted longer in the cell. Quantitative PCR and western blotting confirmed the corresponding changes in transcript and protein abundance, and immunofluorescence microscopy revealed increased accumulation of β-catenin in the nucleus—the compartment where it acts as a transcriptional co-activator. Luciferase reporter assays, in which cells are engineered to glow when TCF/LEF-driven transcription occurs, demonstrated that this nuclear β-catenin was functionally active, driving enhanced TCF/LEF-dependent transcription. The downstream consequence was elevated expression of extracellular matrix genes, including COL1A1 and MMP9, tying the junctional protein loss directly to the fibrotic transcriptional output.

The team then tested the circuit from the opposite direction. When they overexpressed desmoplakin, Wnt/β-catenin signaling and fibrotic gene expression were suppressed, consistent with desmoplakin acting as a homeostatic restraint on the pathway. And when they pharmacologically inhibited Wnt/β-catenin signaling in cells lacking desmoplakin, the increases in ECM-associated gene expression were attenuated—strong evidence that the pathway is not merely correlated with the fibrotic phenotype but is causally required for it. Together, the gain-of-function, loss-of-function, and rescue experiments sketch a coherent model: desmoplakin stabilizes the desmosomal scaffold that retains plakoglobin; plakoglobin, in turn, competes with and restrains β-catenin; when desmoplakin disappears, plakoglobin degrades, β-catenin accumulates in the nucleus, TCF/LEF transcription surges, and the cell begins manufacturing the molecular ingredients of scar tissue.

The findings resonate with related observations in other organs and cell types. Plakophilin-2, another desmosomal protein, has been shown to restrain TGF-β1/p38 MAPK-dependent fibrotic gene expression in cardiomyocytes, and desmoplakin-deficient zebrafish models of cardiac disease show Wnt/β-catenin abnormalities that can be rescued by genetic and pharmacological intervention. The lung appears to follow the same logic: the structural apparatus of epithelial adhesion doubles as a signaling hub, and its erosion converts mechanical vulnerability into biochemical reprogramming. This dual role may explain why genetic variants that subtly lower desmoplakin expression—without abolishing it entirely—could predispose individuals to fibrosis over decades, particularly when combined with environmental insults such as microaspiration, smoke exposure, or viral injury.

The clinical implications are tantalizing but deliberately hedged. Available antifibrotic drugs for idiopathic pulmonary fibrosis slow disease progression modestly, and there is broad agreement that new targets are urgently needed. If reduced desmoplakin function is a driver of fibrotic initiation in susceptible individuals, then preserving desmosomal integrity, stabilizing plakoglobin, or dialing down β-catenin activity in the alveolar epithelium could represent alternative therapeutic strategies. Wnt pathway inhibitors are already in development for cancer and other fibrotic diseases, and the current results suggest a specific epithelial context in which such inhibitors might be beneficial. Conversely, the study complicates the picture for regenerative medicine, because β-catenin signaling is also required for lung development and epithelial repair; any therapeutic manipulation would need to distinguish between protective, transient signaling during wound healing and the chronic, dysregulated activation that drives fibrosis.

The authors are careful to frame their conclusions within the limits of the model system. A549 cells, while convenient and widely used, are a cancer-derived line with alveolar epithelial characteristics rather than genuine primary type II alveolar epithelial cells, and the entire study was conducted in vitro. Whether desmoplakin loss activates the same plakoglobin–β-catenin axis in primary human alveolar epithelial cells, in three-dimensional organoid cultures, or in animal models of fibrosis remains to be demonstrated. The team states explicitly that the disease relevance of the pathway will require validation in primary human alveolar epithelial cells and in vivo models. Nonetheless, by connecting a genetically validated IPF risk gene to a specific signaling mechanism and a concrete transcriptional output—collagen and matrix-remodeling enzymes—the study converts a statistical association into a testable biological hypothesis. It reframes the alveolar epithelium’s adhesive machinery as an active participant in epithelial–matrix crosstalk, and it suggests that the earliest seeds of pulmonary fibrosis may be planted not in the fibroblast, as long assumed, but in the structural proteins that hold the lung’s most vulnerable cells together.

This new publication delves into the emerging role of lactate, a metabolic byproduct traditionally viewed merely as the end product of anaerobic glycolysis. Recent advances in cellular metabolism, especially following the resurgence of interest sparked by the Warburg effect, have redefined lactate as a crucial signaling molecule, fundamentally altering our understanding of cellular bioenergetics. The authors focus on lactate-induced post-translational modifications (PTMs), particularly lactylation, which is a novel biochemical modification whereby lactate contributes to the modification of histone and non-histone proteins, thereby regulating gene expression and cellular function.

In the fibrotic lung microenvironment, metabolic reprogramming is a hallmark feature, with an aberrant accumulation of lactate reported in disease-affected tissues. This metabolic shift not only supports the bioenergetic and biosynthetic demands of activated fibroblasts but also influences the epigenetic landscape through lactylation. The study underscores how lactylation serves as a critical nexus linking altered cellular metabolism with profibrotic gene transcription, thereby promoting fibroblast activation and differentiation — key processes in the relentless progression of PF.

The authors comprehensively review the emerging evidence that implicates lactate and lactylation as pivotal mediators in the fibrotic cascade. The pathologic milieu of PF, characterized by hypoxia and inflammation, fosters a metabolic environment conducive to elevated lactate production. Through lactylation, lactate modifies histones, altering chromatin structure and facilitating the transcription of genes that drive fibrosis. This epigenetic regulation presents a compelling mechanism by which metabolic dysregulation translates into pathogenic cellular behavior.

Furthermore, the article explores the translational ramifications of targeting lactylation pathways for therapeutic intervention. By modulating the enzymes responsible for lactylation or disrupting lactate production and signaling, there lies potential to ameliorate or halt fibrotic progression. These insights align with the burgeoning field of metabolic therapy, where reprogramming cellular metabolism is increasingly recognized as a viable strategy against diverse diseases.

Beyond fibroblast biology, the interplay between immune cells, metabolic reprogramming, and lactylation is highlighted, broadening the contextual framework of PF pathogenesis. Immune cells within the fibrotic niche also undergo metabolic shifts that may influence immune responses and inflammation via lactylation-dependent mechanisms, suggesting a multifaceted role for lactate in cellular communication and disease evolution.

The review meticulously integrates findings from basic research and clinical observations, elucidating the complex metabolic-epigenetic axis involved in PF. It addresses outstanding questions related to the specificity and regulation of lactylation marks, the identity of lactylation substrates beyond histones, and the dynamic responsiveness of this PTM to microenvironmental changes.

Importantly, the authors emphasize the need for innovative analytical tools and models to dissect lactylation’s functional roles in vivo. Advanced mass spectrometry techniques and genetically engineered models are critical for quantifying lactate-induced modifications and assessing their pathophysiological significance. Such approaches will pave the way for precision targeting of lactylation in fibrotic diseases.

The publication also discusses potential biomarkers derived from lactylation profiling that could enable earlier diagnosis and prognosis of PF. Given the silent and progressive nature of the disease, metabolic and epigenetic markers may offer superior sensitivity compared to conventional diagnostic methods.

BIO Integration’s commitment to rapid, open-access dissemination ensures that this seminal work will reach a broad audience, accelerating interdisciplinary dialogue and collaborative efforts toward novel PF treatments. By illuminating the nexus between metabolic rewiring and epigenetic control via lactylation, this article marks a paradigm shift in understanding pulmonary fibrosis.

In sum, this critical review not only reframes lactate’s biological identity beyond a metabolic waste but also positions lactylation as a cornerstone mechanism driving fibroblast activation and fibrotic remodeling. The clinical implications are profound, suggesting new avenues for therapeutic innovation aimed at disrupting the metabolic-epigenetic circuitry underpinning pulmonary fibrosis.

Subject of Research: Pulmonary fibrosis, metabolic reprogramming, lactate signaling, and lactylation in disease progression
Article Title: Lactic acid and Lactylation in the Progression of Pulmonary Fibrosis
News Publication Date: Not specified in the provided content
Web References: http://www.bio-integration.org; http://dx.doi.org/10.15212/bioi-2026-0009
References: Fengxu Wang, Mengna Jiang, Li Zhu et al. Lactic acid and Lactylation in the Progression of Pulmonary Fibrosis. BIOI. 2026. Vol. 7(1). DOI: 10.15212/bioi-2026-0009
Keywords: Pulmonary fibrosis, lactate, lactylation, metabolic reprogramming, fibroblast activation, epigenetic modification, extracellular matrix, post-translational modification, Warburg effect, hypoxia, fibrotic remodeling, biomarker.