Abstract
Studies have reported attenuation of insulin resistance (IR) by improving phosphorylation of the insulin signalling pathway. However, the upstream molecular signalling pathway is still elusive. In this study, Western blot was used to evaluate the phosphorylation level of the insulin signalling pathway and the AMPK pathway. 2-NBDG was used to evaluate glucose uptake. Ca2+ imaging was used to assess change of intracellular Ca2+ concentration. We found that NaHS enhanced the intracellular Ca2+ concentration and glucose uptake and activated the insulin signalling cascade in a palmitic acid (PA)-induced IR model in C2C12 cells. Furthermore, activation of the IRS1/PI3K/AKT pathway and glucose uptake were decreased when AMPK or CaMKKβ was inhibited. Our study also showed that the mitochondrial electron transport chain, ATP production, and intramitochondrial cAMP declined in the IR model but that this effect was reversed by NaHS, an effect that may be mediated by the Ca2+/CaMKK2/AMPK and PI3K/AKT pathways. Our data indicate that H2S improves activation of the insulin signalling cascade and glucose uptake via activation of the Ca2+/CaMKK2/AMPK pathway and mitochondrial metabolism in C2C12 cells. Furthermore, NaHS protects mitochondrial function and maintains normal ATP production by activating the cAMP system and the Ca2+/CaMKK2/AMPK and PI3K/ATK pathways.
Highlights
The cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM) containing 150 μg/ml 2-NBDG for 1 hour at 37 °C. (B) Glucose uptake was decreased, and (C) the expression of p-AKT was decreased after palmitic acid (PA) treatment
Our results demonstrated that the glucose uptake was impaired in the PA-treated group, while it was improved after exogenous H2S was added, which may suggest a beneficial role of NaHS to alleviate insulin resistance
5-aminoimidazole-4-carboxamide riboside (AICAR), a widely used and cell-permeable activator of AMPK, stimulates glucose uptake in skeletal muscle in vivo and in vitro[38,39]. These findings suggest that H2S ameliorates the impaired glucose uptake in an insulin resistance cell model by improving the activity of AMPK, which may respond by increasing the ADP/ATP ratio
Summary
Our data indicate that H2S improves activation of the insulin signalling cascade and glucose uptake via activation of the Ca2+/CaMKK2/AMPK pathway and mitochondrial metabolism in C2C12 cells. Diabetes mellitus (DM) is a common clinical metabolic disorder characterised by hyperglycaemia as a result of insulin resistance (IR) and/or beta-cell failure. A study in an animal model has reported that hydrogen sulphide decreased mechanical ventilation-induced histological damage, inflammation and expression of stress proteins in lungs[5]. Other researchers have reported that diabetic models treated with NaHS decreased oxidative stress[7] and increased glucose uptake[8]. AMPK activation blocks glucose induced insulin secretion in beta cells. Treatment of C2C12 muscle cells with an AMPK agonist had an additive effect on promoting IRS1-associated PI3K activity[13]. The potential mechanisms by which AMPK mediates the pathogenesis of IR and diabetes are still unclear
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
