Abstract
Purpose :
Posterior capsule opacification (PCO) stands out as the prevailing complication following cataract surgery. It arises from a fibrotic process triggered by the trauma inflicted during the surgical procedure, involving wound healing and tissue remodeling. An essential factor in this process is the epithelial-mesenchymal transition (EMT), which plays a pivotal role in the fibrosis of lens epithelial cells (LECs). Previous research, including our own and others', has shed light on the significant contribution of Wnt signaling to the promotion of EMT in LECs following cataract surgery. In the present study, our aim is to investigate the mechanisms through which Wnt signaling initiates and exacerbates LEC fibrosis.
Methods :
Extracellular vesicles (EVs) were extracted from the culture medium of both Wnt3 overexpressed and wild-type FHL124 cells, employing a series of techniques, including differential centrifugation, ultracentrifugation, and further purification through sucrose density gradient ultracentrifugation. To assess Wnt signaling, the Top-flash assay was employed along with the examination of related cascade molecules. Additionally, a Wnt3 knockout mouse model was established, followed by the performance of cataract surgery to investigate the extent of lens epithelium fibrosis compared to WT mice.
Results :
Based on studies involving human donor tissue and mouse cataracts, we observed the upregulation of several Wnt genes following cataract surgery. Notably, when Wnt3 was overexpressed in FHL124 cells, it led to the secretion of Wnt3 protein via exosome-mediated extracellular vesicles (EVs). These EVs carrying Wnt3 had the capacity to activate the Wnt signaling cascade, subsequently inducing fibrosis in FHL124 cells, as evidenced by increased expression of markers such as αSMA, fibronectin, tenascin C, and N-Cadherin. Additionally, markers of the canonical Wnt/β-catenin signaling pathway, namely β-catenin and pSer9-GSK3β, were elevated following treatment with EVs. Furthermore, we are currently conducting investigations involving cataract surgery on Wnt3 knockout (KO) mice to gain further insights into this phenomenon.
Conclusions :
Our discovery highlights that Wnt signaling can trigger fibrotic responses in lens epithelial cells (LECs) via autocrine signaling mechanisms facilitated by extracellular vesicles.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.