2680-P: Cornus officinalis Extract Stimulates the Keap1/Nrf2 Antioxidant Pathway and Reduces Chemokine Secretion in NOD Murine Islets

Introduction and Objective: Type 1 diabetes (T1D) is an autoimmune disease that is characterized by the destruction of pancreatic islets which is preceded by oxidative stress increasing proteome diversity and exacerbating the immune response. T1D interventional therapies may hold promise to inhibit β-cell destruction by enhancing their antioxidative response and decreasing islet derived inflammation. We previously demonstrated that Cornus officinalis (CO) extract, an ethnopharmacological agent, significantly delays T1D onset in nonobese diabetic (NOD) mice. However, we did not fully identify the effect of CO on primary NOD islets. To address this, our objective was to comprehensively and precisely examine the effect of CO on murine NOD islet cellular pathways and chemokine secretion. Methods: 4D proteomic analysis was performed to elucidate the cellular pathways in NOD islets impacted by CO treatment. Female NOD murine islets were isolated and treated with CO followed by protein purification and collection. Samples were then processed for mass spectrometry on a timsTOF Pro mass spectrometer coupled in-line to a NanoElute 2 UHPLC system. Approximately 6500 proteins were identified across treatment groups. To examine anti-inflammatory properties of CO, we performed a multiplexing immunoassay to measure secreted inflammatory markers from CO-treated NOD islets. Results: Significant predicted CO-mediated activation of the Keap1/Nrf2 antioxidant pathway was identified by proteomic analysis. Validation was performed via immunoblotting of downstream Nrf2-associated targets and revealed increased expression of HO1, GCLC, GCLM, and NQO1. Multiplexing immunoassay on CO-treated NOD islets revealed reduced T1D-associated chemokines of CXCL1/10 and CCL2/3/5, respectively. Conclusion: Since Keap1/Nrf2 impairment and increased chemokine secretion have been associated with β-cell death and inflammation, alteration of these pathways with CO may be a promising supplemental interventional treatment for early stage T1D.