Proteomic examination of Cornus officinalis stimulated 1.1B4 human pancreatic cells reveals activation of autophagy and Keap1/Nrf2 pathway.

Type 1 diabetes (T1D) is an autoimmune disease initiated by genetic predisposition and environmental influences culminating in the immunologically mediated destruction of pancreatic ß-cells with eventual loss of insulin production. Although T1D can be accurately predicted via autoantibodies, therapies are lacking that can intercede autoimmunity and protect pancreatic ß-cells. There are no approved interventional modalities established for this purpose. One such potential source for clinical agents of this use is from the frequently utilized Cornus officinalis (CO) in the field of ethnopharmacology. Studies by our lab and others have demonstrated that CO has robust proliferative, metabolic, and cytokine protective effects on pancreatic ß-cells. To identify the molecular mechanism of the biological effects of CO, we performed a proteomic and phosphoproteomic analysis examining the cellular networks impacted by CO application on the 1.1B4 pancreatic ß-cell line. Our label-free mass spectrometry approach has demonstrated significant increased phosphorylation of the selective autophagy receptor of p62 (Sequestosome-1/SQSTM1/p62) and predicted activation of the antioxidant Kelch-like ECH-associated protein 1 (Keap1)/Nuclear factor-erythroid factor 2-related factor 2 (Nrf2) pathway. Further validation by immunoblotting and immunofluorescence revealed markers of autophagy such as increased LC3-II and decreased total p62 along with nuclear localization of Nrf2. Both autophagy and the Keap1/Nrf2 pathways have been shown to be impaired in human and animal models of T1D and may serve as an excellent potential therapeutic target stimulated by CO.

Compositional analysis and biological characterization of Cornus officinalis on human 1.1B4 pancreatic ß cells.

Type 1 diabetes (T1D) is an autoimmune disease resulting from the loss of pancreatic ß cells and subsequent insulin production. Novel interventional therapies are urgently needed that can protect existing ß cells from cytokine-induced death and enhance their function before symptomatic onset. Our initial evidence is suggesting that bioactive ingredients within Cornus officinalis (CO) may be able to serve in this function. CO has been extensively used in Traditional Chinese Medicine (TCM) and reported to possess both anti-inflammatory and pro-metabolic effects. We hypothesize that CO treatment may provide a future potential candidate for interventional therapy for early stage T1D prior to significant ß cell loss. Our data demonstrated that CO can inhibit cytokine-mediated ß cell death, increase cell viability and oxidative capacity, and increase expression of NFATC2 (Nuclear Factor of Activated T Cells, Cytoplasmic 2). We have also profiled the bioactive components in CO from multiple sources by HPLC/MS (High Performance Liquid Chromatography/Mass Spectrometry) analysis. Altogether, CO significantly increases the energy metabolism of ß cells while inducing the NFAT pathway to signal for increased proliferation and endocrine function.