CREB3L1 Modulates Extracellular Matrix Gene Expression and Proliferation in Glaucomatous Lamina Cribrosa Cells

Background: Fibrotic remodelling of the lamina cribrosa (LC) is a defining pathological feature of glaucomatous optic neuropathy and contributes to progressive optic nerve head deformation and axonal vulnerability. LC cells from glaucomatous donors exhibit a myofibroblast-like phenotype characterised by excessive extracellular matrix (ECM) production, a process associated with chronic cellular stress. cAMP responsive element-binding protein 3-like 1 (CREB3L1) is an endoplasmic reticulum-resident transcription factor implicated in stress-responsive regulation of collagen synthesis and matrix homeostasis. The role of CREB3L1 in glaucomatous LC cells, however, remains poorly defined. Methods: Primary human LC cells derived from donors with confirmed glaucoma (GLC; n = 3) and age-matched non-glaucomatous controls (NLC; n = 3) were examined. CREB3L1 expression was assessed at the mRNA and protein levels using quantitative RT-PCR and Western immunoblotting. The functional effects of CREB3L1 suppression were evaluated using siRNA-mediated knockdown in GLC cells, followed by analysis of ECM gene transcription (α-smooth muscle actin, collagen type I alpha 1, fibronectin) and cellular metabolic activity using an MTS assay. Results: CREB3L1 mRNA and protein expression were significantly elevated in GLC cells compared with NLC cells. siRNA-mediated knockdown of CREB3L1 effectively reduced its expression in GLC cells and was associated with significant suppression of profibrotic ECM gene transcription. In addition, CREB3L1 knockdown resulted in a marked reduction in cellular metabolic activity in glaucomatous LC cells. Conclusions: These findings identify CREB3L1 as a regulator of ECM-associated gene expression and cellular behaviour in glaucomatous lamina cribrosa cells. While preliminary, the data suggest that CREB3L1 may contribute to pathological fibrotic remodelling at the optic nerve head. Further mechanistic and in vivo studies will be required to determine whether modulation of CREB3L1-mediated pathways represents a viable therapeutic strategy in glaucoma.