Postganglionic Parasympathetic but Not Postganglionic Sympathetic Neuron Derived Exosomes Inhibit Hyperglycemia Induced Apoptosis in H9c2 Cells

Abstract

Diabetic cardiomyopathy involves the two main types of cell death: apoptosis and necrosis. It is unclear, however, on whether apoptosis induced by hyperglycemia in a cell culture model can be inhibited by postganglionic parasympathetic neuron derived exosomes (PPN‐Exos). Postganglionic parasympathetic and postganglionic sympathetic neurons were isolated, cell cultured, and exosomes were isolated. H9c2 cells were utilized to induce apoptosis via hyperglycemia, which were then divided into 4 groups: 1. Control, 2. H9c2 + Glucose, 3. H9c2 + Glucose + PPN‐Exos, 4. H9c2 + Glucose + postganglionic sympathetic neuron‐derived exosomes (PSN‐Exos). An MTT assay kit was utilized to determine cell proliferation and viability, while apoptosis was determined using TUNEL staining and cell death detection (CDD) ELISA kit. The H9c2 cells that were exposed to glucose displayed significantly (p<0.05) reduced cell viability, and a significant (p<0.05) increase in TUNEL staining and CDD ELISA was present in hyperglycemic H9c2 cells compared to controls and this reduced cell viability and increased apoptosis was reversed with PPN‐Exos but not with PSN‐Exos, suggesting a cell protecting components are present in these PPN‐Exos. Our data on pro‐apoptotic gene expression of caspase‐3 and BAX was significantly (p<0.05) increased in glucose treated H9c2 cells compared with control. These pro‐apoptotic genes were attenuated with PPN‐Exos treatment. Anti‐apoptotic protein Bcl‐2 levels were significantly (p<0.05) reduced in hyperglycemia group and this decrease in Bcl‐2 was improved following PPN‐Exos treatment. In conclusion, our data demonstrate that apoptosis is present in hyperglycemic H9c2 cells mediated through caspase‐3 and BAX pathway is inhibited with PPN‐Exos but not with PSN‐Exos. Our data also suggest that PPN‐Exos must be containing a unique set of protective factors that needs further investigation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.