Abstract
Purpose :
For the first time, we have isolated and cultured trabecular meshwork (TM) cells from a donor with pseudoexfoliation syndrome (PXF). We investigate the mechanism of TM pathogenesis responsible for ocular hypertension in PXF by studying the TM cells and their extracellular matrix (ECM) production under baseline and stressed conditions.
Methods :
TM cells were isolated from a 79-year-old pseudophakic female with diagnosis of PXF. Cells were genotyped to identify known PXF polymorphisms. The PXF TM cells and control TM cells were examined morphologically and tested for TM-specific protein expression. Cells were then tested under stress conditions by treatment with transforming growth factor beta-1 (TGFb-1). TM cells were decellularized to quantify ECM deposition after 4 weeks of culture with and without TGFb-1. ECM protein expression was assessed by Western blot of whole cell lysate and supernatant samples. ECM localization was determined by pan-collagen and fibronectin immunofluorescence.
Results :
The anterior segments from the PXF donor eyes displayed exfoliative material on the zonules and ciliary processes, and the isolated cells from the iridocorneal angle were confirmed to be TM-derived. Genotyping showed that the patient carried multiple high-risk lysyl oxidase-1 (LOXL-1) polymorphisms compared to control TM cells. PXF TM cells expressed similar levels of intracellular ECM proteins with and without TGFb-1. However, TGFb-1 treatment resulted in greater secretion of ECM protein (collagen types I and IV) into the supernatant. Decellularization revealed that PXF TM cells deposited little to no ECM, regardless of TGFb-1 treatment, compared to a rich ECM deposited by control TM cells.
Conclusions :
We have characterized, for the first time, primary PXF TM cells isolated and cultured from a patient carrying high-risk PXF LOXL-1 polymorphisms. Although PXF TM cells expressed normal levels of intracellular ECM proteins, PXF TM cells showed abnormal deposition of ECM with elevated secretion of ECM proteins in the supernatant. These results suggest a defect in ECM fibril assembly, polymerization or cross-linking that may contribute to extracellular accumulation of PXF material.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.