The research team, based at the Eye Center of the Second Affiliated Hospital of Zhejiang University School of Medicine, analyzed anterior lens capsules from 554 patients undergoing cataract surgery between October 2022 and December 2024. The patients were divided into three clinically recognized groups using the Lens Opacities Classification System II: 185 with mild cataracts, 210 with severe cortical cataracts, and 159 with severe nuclear cataracts. Using single-nucleus RNA sequencing, the researchers profiled a staggering 230,838 lens epithelial cells, building one of the most comprehensive cellular atlases of the aging lens capsule assembled to date.

Lens epithelial cells are the only proliferative cells in the lens, and they are essential for maintaining its transparency. Sitting just beneath the anterior capsule, they continuously renew lens fibers and shield the organ from oxidative stress and external damage. When their function deteriorates with age, cataracts follow. But until now, scientists had lacked a detailed map of the distinct cell states within this microenvironment, and how those states shift as cataracts progress from mild clouding to severe opacification.

The atlas revealed seven functionally distinct subpopulations of lens epithelial cells, which the team named according to their dominant gene expression profiles: secretory, regulatory, protective, metabolic, homeostatic, fibrotic, and extracellular-matrix-regulatory cells. As disease advanced, the proportions of the protective, homeostatic, and fibrotic subpopulations steadily declined, while the extracellular-matrix-regulatory group expanded. This shifting balance suggests that specific cell states govern the transitions between mild and severe disease, and that preserving vulnerable subpopulations might one day slow or prevent progression.

The most striking discovery concerned the secretory subpopulation, designated Cluster 0. Gene enrichment analyses showed that neurotrophic signaling pathways, particularly the SLIT-ROBO pathway, which normally guides axonal growth and neural progenitor proliferation, were active across the cataract groups. Immunofluorescence staining then confirmed the presence of beta-III tubulin-positive, axon-like structures penetrating the capsular periphery of cataract patients. No such structures were detected in the transparent lens capsules of healthy organ donors. In severe nuclear cataracts, the density of these axon-like projections was roughly eight to sixteen times higher than in the mild and severe cortical groups, respectively.

To trace the origin of these signals, the team integrated their lens data with single-nucleus sequencing data from human sympathetic ganglia. The analysis identified a specific neuronal subcluster, Sympathetic_neurons2, as the most interactive neural population, and pinpointed a molecular axis at the heart of the communication: Cluster 0 cells express high levels of the neurotrophic factor NRG1, which pairs with the ERBB3 receptor on sympathetic neurons. Immunofluorescence confirmed that both NRG1 and ERBB3 were dramatically elevated in severe nuclear cataract capsules compared with normal tissue, with NRG1 expression increasing several hundredfold.

Within Cluster 0 itself, further subclustering revealed three cell states: S100A4-positive, SYN3-positive, and MT-CO1-positive lens epithelial cells. As cataracts progressed, the SYN3-positive population, associated with neurotrophic signaling, expanded, while the MT-CO1-positive population, tied to mitochondrial energy production, shrank. This pattern echoes earlier findings that the mitochondrial protein MT-CO1 is upregulated early in cataract development to sustain ATP production but collapses in advanced opacification, and that Synapsin III expression rises in aged lenses, potentially reflecting age-related stress responses.

The study also documented a breakdown in the mechanisms that normally restrain nerve growth. SEMA3 signaling, which repels axons and prevents them from invading inappropriate tissue regions, shifted from coordinated expression across multiple cell subpopulations in mild cataracts to dominance by single clusters in severe disease. The researchers propose that this loss of inhibitory control, combined with aging-driven activation of NRG signaling, permits aberrant axonal proliferation into the capsule. Meanwhile, distinct metabolic signatures separated the two severe subtypes: cortical cataracts were enriched for calcium transport pathways, a known driver of lens protein degradation, while nuclear cataracts showed activation of ferroptosis pathways, the iron-dependent cell death process increasingly implicated in lens clouding.

The clinical implications are tantalizing. Because the NRG1-ERBB3 axis appears to be a central driver of the neural ingrowth associated with cataract progression, the authors suggest that targeted therapies, such as NRG1 antibodies, could eventually modulate these neurotrophic pathways. Prior work has shown that ERBB-family signaling participates in lens fibrosis and epithelial-mesenchymal transition after cataract surgery, and that NRG1 signaling can suppress stress-induced cellular senescence in vascular tissue, lending plausibility to the idea that manipulating this axis could influence lens aging more broadly. Still, the researchers caution that their study has limits: single-nucleus sequencing requires dissociating tissue, severing the spatial relationships between cells, and the exact origin of the axon-like structures remains unresolved.

The team plans to address these gaps with spatial transcriptomics, which preserves tissue architecture while mapping gene expression, and with functional validation of axonal growth in organoid-based models. For now, the study reframes age-related cataracts as a disease of cellular heterogeneity and aberrant neuro-lens communication rather than a uniform degenerative process. With the global population aged 60 and over projected to grow by 1.4 billion by 2030, and cataract prevalence exceeding 92 percent in people over 80, understanding the molecular choreography of lens aging has never mattered more. If the neural invasion of the aging lens can be intercepted, the first genuine preventive treatment for the world’s leading cause of blindness may become a realistic goal.

Subject of Research: Single-nucleus sequencing of human age-related cataract lens capsules identifying neural ingrowth and cell subpopulations in lens aging

Article Title: Deconstruction of Human Age‐Related Cataract Capsules Defines Aging

Article References: Tang, Q., Tong, Z., Fan, C., Chen, S., Guo, J., Hu, J., Yao, K., Yin, Z., Chen, X., & Yu, Y. (2026). Deconstruction of Human Age‐Related Cataract Capsules Defines Aging. Advanced Science, 13(55), Article e76532. https://doi.org/10.1002/advs.76532

Image Credits: AI Generated

DOI: 10.1002/advs.76532

Keywords: age-related cataract, lens epithelial cells, single-nucleus RNA sequencing, NRG1-ERBB3 signaling, neural ingrowth, lens capsule, SLIT-ROBO pathway, ferroptosis, calcium signaling, mitochondrial dysfunction, cell atlas, sympathetic neurons

Primary angle-closure glaucoma, or PACG, is particularly prevalent in East Asian populations and arises when the iris physically blocks the drainage angle of the eye, driving up intraocular pressure. Because the lens sits directly behind the iris and a thickened or enlarged lens can itself promote closure of the angle, ophthalmologists have suspected for decades that lens biology and PACG are intertwined. What has been missing is a molecular account of that relationship. The anterior lens capsule is not merely packaging; it is a biologically active interface through which nutrients, signaling molecules, and waste products pass, and it houses the lens epithelial cells that maintain lens transparency throughout life. Until now, its protein landscape in PACG had remained essentially uncharted.

To build that map, the team turned to data-independent acquisition mass spectrometry, a proteomic technique that systematically measures thousands of proteins in a sample with high reproducibility. They compared anterior lens capsule specimens from patients undergoing cataract surgery who had age-related cataract alone against those who had cataract combined with PACG. After rigorous quality control, the analysis included 13 capsules from the cataract-only group and 10 from the PACG group. The comparison yielded a striking result: 1,262 proteins were differentially expressed between the two conditions, a scale of molecular remodeling far beyond what anyone had anticipated in this thin sheet of tissue.

The direction of the changes proved as informative as their number. Proteins that were reduced in PACG-associated capsules were enriched for networks governing proteostasis — the cell’s system for maintaining properly folded, functional proteins — including molecular chaperones and the neddylation pathway, a modification cascade that regulates protein degradation machinery. When the researchers ran these depleted proteins through enrichment and protein-protein interaction network analyses, they converged on a common hub: lysosome-related dysfunction. Lysosomes are the cell’s acidic recycling compartments, and their proper function depends on the vacuolar-type H+-ATPase, or V-ATPase, the proton pump that acidifies them. In the PACG capsules, ATP6V1A — a major subunit of that pump — was coordinately decreased alongside additional V-ATPase subunits, the lysosomal membrane protein LAMP2, and members of the Rag GTPase family, which regulate lysosomal signaling and nutrient sensing.

On the other side of the ledger, proteins that were increased in the PACG capsules were enriched for extracellular matrix remodeling and lipid and glycan metabolic pathways. That pattern suggests the capsule in PACG eyes is not simply degenerating; it is actively restructuring, with potential consequences for the mechanical relationships between the lens, iris, and drainage angle that define angle-closure disease. The researchers also performed receiver operating characteristic analyses to evaluate how well the differential proteins distinguished the two patient groups, an early step toward assessing whether such markers could eventually support clinical classification.

A single proteomic comparison, however compelling, cannot establish mechanism. So the team pursued ATP6V1A through an unusually thorough series of validation experiments. They confirmed reduced ATP6V1A in human anterior lens capsule flat mounts — whole-mount preparations that preserve the spatial architecture of the tissue. They then applied pressure stress to lens epithelial cells in culture, mimicking the mechanical environment of elevated intraocular pressure, and again observed ATP6V1A reduction. Retinal stress models, including ischemia-reperfusion paradigms, reproduced the signal, and — critically — so did peripheral blood mononuclear cells drawn from an additional small clinical cohort of patients with PACG. The consistency of the ATP6V1A decrease across human tissue, cell culture, animal models, and circulating immune cells lent substantial weight to the finding.

To test whether the loss of this proton pump actually matters functionally, the researchers used pharmacologic inhibition of the V-ATPase. The result was telling: disrupting the pump disturbed lysosomal homeostasis before any overt loss of cell viability could be detected. In other words, lysosomal dysfunction is not merely a late consequence of dying cells; it is an early event that precedes cell death, positioning it as a plausible upstream driver of lens epithelial injury rather than a passive byproduct. This temporal ordering is what elevates ATP6V1A from a correlational marker to a candidate mechanistic link between elevated intraocular pressure, lens epithelial damage, and the coexistence of PACG with age-related cataract.

The study also looked outward, to an independent population-scale dataset. The team examined an exploratory plasma proteomic dataset from the UK Biobank, a large-scale biomedical resource containing health data from hundreds of thousands of participants. Notably, the ATP6V1A signal itself did not reappear in circulating plasma, a reminder that tissue-resident protein changes do not always translate to the bloodstream and that plasma proteomics has inherent limitations for detecting organ-specific molecular events. Yet the UK Biobank analysis did provide external support for glaucoma-associated lens-related and metabolic alterations, independently corroborating the broader biological themes — if not the specific protein — that emerged from the capsule analysis.

The implications reach in several directions at once. Clinically, the findings suggest that the lens capsule could serve as a readout of molecular stress in glaucoma, and that ATP6V1A-associated lysosomal dysfunction might eventually inform how ophthalmologists understand and stratify patients whose cataract and glaucoma travel together. Mechanistically, the work reframes the lens as an active participant in PACG pathogenesis: pressure stress appears to erode the very machinery that lens epithelial cells need to recycle damaged proteins and maintain transparency, and that erosion is detectable in the capsule before cells die. If lysosomal failure is indeed an early, targetable event, it opens a conceptual window for interventions aimed at preserving proteostasis in the stressed lens — though the authors are careful to frame ATP6V1A as a candidate link, not a proven therapeutic target.

There are, of course, limits to what any single study can establish. The clinical cohorts were small — 13 and 10 capsules in the primary comparison, plus a modest validation cohort — and the UK Biobank plasma analysis failed to recapitulate the central signal. The study was conducted in accordance with the Declaration of Helsinki, approved by the Ethics Committee of Xiangya Hospital, and registered with the Chinese Clinical Trial Registry, with animal work separately approved by the institution’s animal care committee, but replication in larger and more diverse populations will be essential before these molecular signatures enter clinical practice. Even so, the scale of the proteomic remodeling documented here — more than 1,200 differential proteins converging on a single lysosomal hub — makes a persuasive case that the anterior lens capsule has been telling a molecular story all along, and that researchers are only now learning to read it. For the millions of people, particularly across Asia, who face the double burden of cataract and angle-closure glaucoma, that story may ultimately point toward new ways of protecting both the clarity of the lens and the survival of the sight it helps deliver.

Subject of Research: Proteomic identification of ATP6V1A-associated lysosomal dysregulation in the anterior lens capsule in age-related cataract with primary angle-closure glaucoma

Article Title: Comparative proteomics of human anterior lens capsules reveals ATP6V1A-associated lysosomal dysregulation in age-related cataract with primary angle-closure glaucoma

Article References: Liu, J., Wang, J., Zeng, Y., Zhao, Z., Zhu, P., Liu, Y., Dong, Q., Zhao, J., Xia, X., Rong, R., & Ding, L. (2026). Comparative proteomics of human anterior lens capsules reveals ATP6V1A-associated lysosomal dysregulation in age-related cataract with primary angle-closure glaucoma. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-08934-0

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08934-0

Keywords: primary angle-closure glaucoma, age-related cataract, anterior lens capsule, proteomics, ATP6V1A, lysosomal dysfunction, V-ATPase, lens epithelial cells, intraocular pressure, proteostasis, UK Biobank, mass spectrometry