Retinal Muller Glial Cells in the initiation of diabetic retinopathy

PROJECT SUMMARY/ABSTRACT The molecular mechanisms responsible for the initiation of diabetic retinopathy (DR), and the primary cellular targets of diabetes in the retina have not been fully elucidated. This represents a significant barrier to the development of effective therapies to prevent or slow down the initiation of the disease. When challenged by diabetes, retinal neurons, glia, and the vasculature all display abnormalities. Even though it is currently not clear which cell types are the primary targets of diabetes, Müller glial cells (MG), as one of the first responders of diabetes in the retina, are essential for the development of diabetic retinopathy. However, the molecular mechanisms controlling the diabetes-induced Müller glial responses remain understudied. We applied single cell transcriptomic analysis (single cell RNA-seq) to systematically profile diabetes- induced multicellular responses in the retina of diabetic rat models (preliminary studies). Among the 53 types of retinal cell detected by single cell RNA-seq, MG were one of the first responders to diabetes at the transcriptional level. Notably, MG initially upregulated genes that play protective roles in other systems, including anti-apoptosis, anti-proliferation, anti-oxidation, and anti-inflammation genes, but failed to maintain expression levels of these protective genes as the disease progressed. This failure could contribute to the development of DR. We hypothesize that MG exert protective roles by upregulating protective genes in the early stage of DR, and that enhancing this intrinsic protective mechanism will protect the retina from diabetes- induced damage. The proposed studies will test this hypothesis in two aims. In Aim 1, we will focus on studying one of the candidate protective genes, Zinc finger protein 36 homolog (Zfp36), which was initially upregulated by diabetes in MG and then downregulated as DR progressed, using diabetic rat models. In Aim 2, we will determine whether multiplexing activation of protective pathways in MG with a novel CRISPR-based technique can further protect the retina from diabetes-induced damage. In summary, the proposed study aims to uncover the roles of MG in initiating DR, focusing on dissecting their protective effects. This work will lead to better understanding of DR and new therapeutic candidates.