Prominin-1 Knockdown Causes RPE Degeneration in a Mouse Model

There are currently no effective treatments for retinal pigment epithelial (RPE) cell loss in atrophic AMD (aAMD). However, our research on (), a known structural protein in photoreceptors (PRs), has revealed its distinct role in RPE and offers promising insights. While pathogenic mutations have been linked to macular diseases with RPE atrophy, the broader physiological impact of dysfunctional in RPE loss is unclear. We have shown that plays a role in regulating autophagy and cellular homeostasis in and RPE (mRPE) cells in vitro. Nevertheless, a comprehensive understanding of its in vivo expression and function in mRPE remains to be elucidated. To characterize expression in RPE in situ, we used RNAscope assays and immunogold electron microscopy (EM). Our use of chromogenic and fluorescent RNAscope assays in albino and C57BL/6J retinal sections has revealed mRNA expression in perinuclear regions in mRPE in situ. Immunogold EM imaging showed expression in RPE cytoplasm and mitochondria. To confirm expression in RPE, we interrogated RPE single-cell RNA-sequencing datasets using an online resource, Spectacle. Our analysis showed expression in RPE. To investigate 's function in RPE homeostasis, we performed RPE-specific knockdown (KD) using subretinal injections of AAV2/1.CMV.saCas9.U6.gRNA in male and female . Our data show that RPE-specific -KD in vivo resulted in abnormal RPE morphology, subretinal fluid accumulation, and secondary PR loss. These changes were associated with patchy RPE cell death and reduced a-wave amplitude, indicating retinal degeneration. Our findings underscore the central role of in cell-autonomous mRPE homeostasis. The implications of -KD causing aAMD-like RPE defects and retinal degeneration in a model are significant and could lead to novel treatments for aAMD.