Evidence of a novel gene HERPUD1 in polypoidal choroidal vasculopathy

Polypoidal choroidal vasculopathy (PCV) is an exudative maculopathy, with clinical features distinct from neovascular age-related macular degeneration (nAMD) which is the leading cause of irreversible blindness in the elderly. Our studies focused on the genetic background and function of a novel gene HERPUD1 in PCV. HERPUD1 has been reported to increase the level of amyloid β (Aβ), which is a component of drusen deposits underlying the retinal pigment epithelium (RPE) layer. To verify the genetic functional associations of HERPUD1 with PCV, exome sequencing of HERPUD1 was performed in unrelated Chinese individuals, including nAMD patients, PCV patients and control subjects. Immunohistochemistry assays for HERPUD1 were performed in the subretinal membranes of PCV patients. The relationship between HERPUD1 and amyloid beta precursor was determined using real-time PCR in HERPUD1-overexpressing RPE cells. The gene expression patterns of angiogenesis cytokines and chemokines in both Aβ-treated RPE cells and in Brown Norway rats that received Aβ subretinal injections were determined. We showed that HERPUD1 rs2217332 is significant associated with Chinese PCV, and HERPUD1 was expressed in PCV subretinal membranes. Besides, Plasma Aβ42 protein was significantly higher in PCV patients compared to nAMD and control subjects. Aβ could upregulate angiogenic factors, chemokines and matrix metalloproteinases both in RPE cells and in a rat model of subretinal Aβ injection. The imbalance of the cytokines may be one of the mechanisms for the formation and development of PCV. Our results strongly suggest that HERPUD1 is highly associated with PCV patients.