The Impact of WDR36 Variants and p53 in Glaucoma

About This Grant

PROJECT SUMMARY Primary Open Angle Glaucoma (POAG) affects three million people in the US, with nearly half unaware they have the disease. Major risk factors include elevated intraocular pressure, age, and genetics, with genetics increasing the risk of developing POAG by almost ninefold. The discovery of genes associated with POAG can not only be used to help predict a patient’s risk but also enables earlier diagnosis and development of treatments targeting the underlying biology of the disease. This research focuses on understanding how variants in the WDR36 gene contribute to glaucoma and whether retinal ganglion cells (RGCs) harboring mutations in this gene respond to gene augmentation. Although WDR36 variants are present in 5.6% of POAG patients (compared with 1% in controls), certain variants are associated with more severe and early-onset disease. Investigating these variants is critical for understanding disease mechanisms and calculating disease risk. Our central hypothesis is that variants of WDR36 worsen RGC loss by disrupting ribosomal assembly, increasing sensitivity to p53-driven cell death during aging and with elevated intraocular pressure. Our study focuses on the WD40 domain of WDR36, which plays a role in ribosomal assembly and may trigger early RGC death via the p53-MDM2 anti-apoptosis pathway. We have developed a mouse model with a WDR36 mutation that demonstrates an age and IOP-dependent phenotype of the disease. We will also use human stem cells from non-glaucomatous eyes and cells with clinically relevant mutations in the WDR36 WD40 domain to differentiate into RGCs to study how mutations in the WD40 domain influence cell survival and morphology. Additionally, we’ve created viral vectors to test if gene augmentation therapy can stop the progression of the disease phenotype and reverse pathologic mechanisms. To test this hypothesis, we will use mouse and human models to investigate the role of the variants on cell morphology and survival, as well as whether the augmentation with normal WDR36 alleviates or slows disease progression (Aim 1). Using stem cells differentiated into RGCs, we will explore how WDR36 variants interfere with the p53-MDM2 pathway, which regulates cell death but has not been well-studied in RGCs (Aim 2). By manipulating this pathway through gene augmentation and specific inhibitors, we aim to slow or prevent early RGC degeneration in patients harboring these mutations. In addition to providing a framework for studying other genetic forms of POAG, this specific project will help us better understand the genetic mechanisms behind a genetic form of POAG and assess the potential for gene therapy to treat it.