Targeting LRPPRC to improve corneal wound healing via augmenting autophagy and suppressing TGF-β/Smad signaling...

Following corneal injury, the body initiates wound healing to maintain corneal function. Activation of the transforming growth factor beta (TGF-β) pathway promotes corneal stromal fibroblasts differentiation, leading to the excessive secretion of extracellular matrix (ECM) components, such as fibronectin and collagen, which contribute to stromal deposition, scar formation, and vision impairment. Although autophagy, a key regulatory pathway in corneal alkali burn repair, is critically modulated by the autophagy-inhibiting protein Leucine-Rich Pentatricopeptide Repeat Containing (LRPPRC), its specific role in this reparative process remains unclear.

A corneal alkali burn mouse model was established, and day 14 post-injury was selected as the primary time point for analysis (n = 6 per group). The expression and distribution of LRPPRC were assessed by Western blot and immunofluorescence (IF). To investigate the effects of LRPPRC downregulation on corneal injury, anterior chamber injection of LRPPRC-shRNA and ocular surface application of the LRPPRC-specific inhibitor Gossypol-Acetic Acid (GAA) eye drops were administered. Corneal opacity was assessed by slit-lamp photography, while fluorescein sodium staining evaluated the area of corneal damage. Anterior segment optical coherence tomography (OCT) and H&E staining measured corneal thickness and the degree of angle closure. CD31 staining assessed corneal neovascularization. The expression of the TGF-β pathway, ECM proteins, autophagy-related proteins, and inflammatory factors were evaluated by Western blot and IF.

Mice with corneal alkali burns exhibited characteristic pathological features, including severe corneal edema, neovascularization, and anterior chamber angle closure, and the expression level of LRPPRC exhibited a time-dependent increase. Following LRPPRC knockdown via shRNA or pharmacological inhibition with GAA, treated corneas demonstrated significant alleviation of edema and neovascularization, along with attenuated anterior chamber angle closure. Mechanistically, LRPPRC silencing suppressed TGF-β/Smad pathway, fibroblast activation and ECM deposition (e.g., fibronectin), while simultaneously enhancing autophagy-related protein expression, thereby facilitating ECM degradation during corneal repair. Notably, GAA treatment suppressed TGF-β-driven fibrotic responses in human corneal stromal cells (HCSCs), characterized by diminished expression of α-SMA, collagen, and fibronectin aggregates.

LRPPRC inhibition demonstrated efficacy in alleviating pathological corneal fibrosis and neovascularization via suppression of fibroblast activation and ECM deposition post-corneal injury. These findings highlight LRPPRC as a tractable therapeutic target for corneal alkali burns, with GAA as a pharmacological agent offering a clinically translatable intervention.