Enzyme Autotaxin Drives Scarring in the Optic Nerve’s Load-Bearing Scaffold in Glaucoma

Glaucoma remains the leading cause of irreversible blindness worldwide, and for decades the central villain in the story has been elevated pressure inside the eye. Yet a growing body of evidence suggests that the damage inflicted on the optic nerve is not simply a matter of mechanical squeezing. Behind the pressure, a quieter process of tissue scarring — fibrosis — reshapes the very structures meant to protect the nerve. Now, a team of researchers at University College Dublin and collaborating institutions has identified a molecular driver of that scarring in one of the eye’s most vulnerable structures, and their findings point to a druggable enzyme that may help halt the disease at a deeper level.

The structure in question is the lamina cribrosa, a lattice-like sieve of connective tissue through which roughly a million retinal ganglion cell axons funnel on their way from the eye to the brain. Because it bears the brunt of intraocular pressure, the lamina cribrosa is widely regarded as the principal site of glaucomatous damage. When pressure rises, this porous scaffold deforms, and the specialized cells that maintain it — lamina cribrosa cells — respond by remodeling their surroundings. In glaucoma, that remodeling tips from healthy maintenance into pathological overproduction of extracellular matrix, the fibrous protein network that gives tissues their shape. The result is a stiffened, scarred sieve that strangles the axons passing through it.

The Dublin-led team, publishing in Scientific Reports, focused on a signaling pathway already implicated in fibrosis elsewhere in the eye: the enzyme autotaxin and its product, lysophosphatidic acid, commonly abbreviated LPA. Autotaxin is secreted by cells and circulates in the blood and other body fluids, where it performs a single catalytic trick — it cleaves lysophosphatidylcholine, an abundant membrane lipid, to generate LPA. LPA then signals through a family of dedicated receptors on the cell surface, and among its many effects is a potent pro-fibrotic program: it stimulates cells to proliferate and to lay down collagen, fibronectin and other matrix proteins. Previous work had shown this axis at work in the trabecular meshwork, the drainage tissue whose clogging raises intraocular pressure in the first place. The new study asked whether the same machinery operates downstream, in the lamina cribrosa itself.

To find out, the researchers cultured lamina cribrosa cells from two sources: donors who had suffered from glaucoma and donors with healthy eyes. They then compared the two populations across several molecular readouts. Using real-time quantitative polymerase chain reaction, they measured the messenger RNA encoding autotaxin; using western blotting and immunofluorescence, they quantified and localized the protein itself; and using a phospholipase activity assay, they measured how much functional enzyme the cells were releasing into their culture medium. This triangulation of gene expression, protein abundance and enzymatic activity is a rigorous way to establish that a pathway is genuinely upregulated rather than merely transcribed.

The results were unambiguous. Glaucomatous lamina cribrosa cells expressed significantly more autotaxin than normal cells, with messenger RNA levels elevated roughly 3.84-fold and protein levels about 1.54-fold compared with controls, differences that reached statistical significance. The cells also carried more of the docking stations through which LPA exerts its effects. Of the LPA receptors examined, one stood out: LPA3 was overexpressed approximately 2.73-fold in the glaucomatous cells, a highly significant difference. In other words, the scarring-prone cells were not only producing more of the enzyme that manufactures LPA — they were also better equipped to hear its signal once it was made. That combination of heightened ligand production and heightened receptor expression describes a pathway primed for self-reinforcing activation.

Correlation alone, however, does not prove causation. To test whether autotaxin was actually driving the fibrotic behavior of glaucomatous lamina cribrosa cells, the team turned to S32826, a selective pharmacological inhibitor of the enzyme. When the glaucomatous cells were treated with the inhibitor, autotaxin activity in the culture medium dropped significantly, and with it fell two hallmarks of fibrosis. The first was cell proliferation: the treated cells multiplied more slowly, suggesting that autotaxin-derived LPA was fueling the expansion of the matrix-producing cell population. The second was matrix gene expression. Levels of COL1A, the gene encoding type I collagen — the main structural protein of scar tissue — fell to about 0.51-fold of untreated levels, while FN1, encoding fibronectin, a glycoprotein that organizes the matrix scaffold, fell to about 0.64-fold, both statistically significant reductions.

These numbers matter because they sketch a coherent mechanism. In the glaucomatous optic nerve head, lamina cribrosa cells appear locked into a state of excess autotaxin production. The enzyme they secrete converts membrane lipids into LPA in their immediate environment, and the LPA, acting through upregulated receptors such as LPA3, pushes the cells to divide and to deposit collagen and fibronectin. The accumulating matrix stiffens the lamina cribrosa, altering its biomechanics and compromising the axons it supports. Blocking the enzyme at the top of this cascade simultaneously damped proliferation and matrix production, which is exactly what one would want from a therapeutic intervention aimed at breaking the cycle rather than treating its downstream consequences.

The clinical implications are considerable. Current glaucoma therapy is almost entirely devoted to lowering intraocular pressure — through eye drops, laser treatment or surgery — and while pressure reduction slows progression for many patients, a substantial number continue to lose vision. Moreover, some patients with normal eye pressures still develop glaucomatous damage, hinting that pressure-independent mechanisms contribute to the disease. A fibrosis-directed therapy targeting the optic nerve head itself would represent a fundamentally different approach: rather than reducing the force acting on the lamina cribrosa, it would strengthen the tissue’s resistance to scarring and preserve the environment through which the axons must pass. Because autotaxin inhibitors are already an active area of pharmaceutical development — the pathway has been pursued in fibrotic lung disease, cancer and chronic inflammation — a repurposing path toward ocular neuroprotection is at least conceivable, though the authors are careful to frame their work as identifying a potential target rather than delivering a treatment.

There are, of course, important caveats. The study was conducted in cultured cells from donor tissue, an indispensable but simplified model that cannot fully reproduce the mechanical, vascular and immune environment of the living optic nerve head. The sample of donor cells, while sufficient to detect statistically robust differences, represents the diversity of glaucoma imperfectly, and the inhibitor experiments were performed in vitro, where drug concentrations and exposure differ from anything achievable in human eyes. Delivering an autotaxin inhibitor to the lamina cribrosa — whether as an eye drop, an injection or a sustained-release implant — would require solving significant pharmacological challenges. Long-term suppression of a signaling pathway as widespread as LPA also raises questions about effects on other tissues, since autotaxin and LPA participate in vascular function, wound healing and immune regulation throughout the body.

Even with those caveats, the study adds an important piece to the glaucoma puzzle. It extends the autotaxin–LPA fibrosis axis from the trabecular meshwork to the lamina cribrosa, connecting the pressure-generating machinery of the eye’s drainage system with the pressure-suffering scaffold of the optic nerve. It identifies a specific receptor, LPA3, as a candidate mediator of the response. And it demonstrates that a small-molecule inhibitor can reverse key fibrotic behaviors in glaucomatous cells, providing proof of principle that the pathway is pharmacologically tractable. For a disease in which irreversible blindness affects tens of millions of people and existing therapies leave many behind, the discovery that a single enzyme helps drive scarring in the optic nerve’s load-bearing sieve is more than an incremental finding — it is a new door, and one that researchers on both the laboratory and clinical sides of ophthalmology will be eager to walk through.

Subject of Research: The role of the autotaxin–lysophosphatidic acid signaling pathway in fibrosis of the lamina cribrosa in glaucoma

Article Title: Autotaxin induces fibrosis in lamina cribrosa cells in glaucoma

Article References: O’Regan, A., Irnaten, M., Eivers, S., O’Callaghan, J., Wallace, D., & O’Brien, C. J. (2026). Autotaxin induces fibrosis in lamina cribrosa cells in glaucoma. Scientific Reports. https://doi.org/10.1038/s41598-026-74457-9

Image Credits: AI Generated

DOI: 10.1038/s41598-026-74457-9

Keywords: glaucoma, autotaxin, lysophosphatidic acid, lamina cribrosa, fibrosis, extracellular matrix, LPA3 receptor, optic nerve head, S32826 inhibitor, trabecular meshwork, cell proliferation, intraocular pressure