Single-Cell RNA Sequencing Reveals a Role for Reactive Oxygen Species and Peroxiredoxins in Fatty Acid-Induced Rat -Cell Proliferation

The functionalmass of insulin-secreting pancreatic b-cells expands to maintain glucose homeostasis in the face of nutrient excess, in part via replication of existing beta-cells. Type 2 diabetes appears when these compensatory mechanisms fail. Nutrients including glucose and fatty acids are important contributors to the b-cell compensatory response, but their underlying mechanisms of action remain poorly understood. We investigated the transcriptional mechanisms of beta-cell proliferation in response to fatty acids. Isolated rat islets were exposed to 16.7 mmol/L glucose with or without 0.5mmol/L oleate (C18:1) or palmitate (C16:0) for 48 h. The islet transcriptome was assessed by single-cell RNA sequencing. b-Cell proliferation was measured by flow cytometry. Unsupervised clustering of pooled beta-cells identified different subclusters, including proliferating beta-cells. beta-Cell proliferation increased in response to oleate but not palmitate. Both fatty acids enhanced the expression of genes involved in energy metabolism and mitochondrial activity. Comparison of proliferating versus non-proliferating b-cells and pseudotime ordering suggested the involvement of reactive oxygen species (ROS) and peroxiredoxin signaling. Accordingly, N-acetyl cysteine and the peroxiredoxin inhibitor conoidin A both blocked oleate-induced beta-cell proliferation. Our study reveals a key role for ROS signaling through peroxiredoxin activation in oleate-induced b-cell proliferation.