Non-Viral Gene Therapy in Trabecular Meshwork Cells to Prevent Fibrosis in Minimally Invasive Glaucoma Surgery

: The primary cause of failure for minimally invasive glaucoma surgery (MIGS) is fibrosis in
the trabecular meshwork (TM) that regulates the outflow of aqueous humour, and no anti-fibrotic
drug is available for intraocular use in MIGS. The myocardin-related transcription factor/serum
response factor (MRTF/SRF) pathway is a promising anti-fibrotic target. This study aims to utilise
a novel lipid nanoparticle (LNP) to deliver MRTF-B siRNA into human TM cells and to compare
its effects with those observed in human conjunctival fibroblasts (FF). Two LNP formulations were
prepared with and without the targeting peptide cY, and with an siRNA concentration of 50 nM.
We examined the biophysical properties and encapsulation efficiencies of the LNPs, and evaluated
the effects of MRTF-B silencing on cell viability, key fibrotic genes expression and cell contractility.
Both LNP formulations efficiently silenced MRTF-B gene and were non-cytotoxic in TM and FF
cells. The presence of cY made the LNPs smaller and more cationic, but had no significant effect on
encapsulation efficiency. Both TM and FF cells also showed significantly reduced contractibility after
transfection with MRTF-B siRNA LNPs. In TM cells, LNPs with cY achieved a greater decrease in
contractility compared to LNPs without cY. In conclusion, we demonstrate that the novel CL4H6-
LNPs are able to safely and effectively deliver MRTF-B siRNA into human TM cells. LNPs can serve
as a promising non-viral gene therapy to prevent fibrosis in MIGS.