Author + information
Although percutaneous coronary interventional (PCI) therapy for acute myocardial infarction (AMI) could open the blocked blood vessels, it induced H/R injury in cardiac cells due to the excessive production of ROS, which perturbed the intracellular redox balance and led to oxidative stress that contributed to cell dysfunction and programmed cell death. This study is aimed at exploring the effects of semaglutide on CMEC and the mechanisms by which semaglutide reduce the CMEC oxidative stress apoptosis under hypoxia/reoxygenation (H/R) model.
In vitro cultured CMECs of SD rats were purified by differential adhesion method and identified immunocytochemically using CD31 antibody and factor VIII. GLP-1R and CD31 was assessed by co-location immunohistochemistry. MTT assay was performed to assess the proliferation of the first-generation cells exposed to different concentrations (0-100 nm/L) of semaglutide. H/R model was used to induce cellular apoptosis, and the apoptotic rate was assessed by low cytometry. Fura-3 AM was applied to observed the concentration of Ca2+. DCFHDA was used to evaluate the ROS contents. Western blots and immunohistochemistry were used to assess the expression of XO and caspase3. Pathways inhibitors and siRNA technology were used to illustrate the role of PI3K/Akt-Survivin in semaglutide -mediated anti-apoptotic actions.
Immunocytochemical staining demonstrated a proportion of double positive cells isolated in vitro exceeding 95%. Semaglutide exposure concentration-dependently promoted the proliferation of CMECs with the optimal concentration of 100 nmol/L. H/R increased the contents of ROS that is responsible for cellular apoptosis and, however, semaglutide could reversed such changes. H/R down-regulated SERCA2a and up-regulated IP3R transcription that induce Ca2+ overload and subsequent XO expression and ROS contents. Inhibition of SERCA2a, chelation of Ca2+, knockdown of XO with siRNA significantly reduce ROS contents and caspase3 expression. Semaglutide treatment could reverse SERCA2a and inhibit IP3R to reduce Ca2+ overload and consequent XO activation, ROS outburst and cellular apoptosis. Semaglutide could preserve the ΔΨm, block mPTP opening and Cytc distribution via inhibition of XO-ROS, which suppress the mitochondrial apoptotic pathways. Inhibition of GLP-1R, knockdown of surviving could depress the protective effects of Semaglutide on apoptotic signals SR-Ca2+-XO-ROS, hich reduce SERCA2a expression and activity. Besides, Semaglutide could increase the SOD, GSH and GPx to limite the normal ROS contents.
1. H/R induced excessive ROS via SR-Ca2+-XO to induce mitochondrial apoptotic pathways, which was reversed by semaglutide.
2. Semaglutide, on one hand, could enhance SOD, GSH and GPx to conteract excessive ROS, and on the other hand, it activated GLP-1R/PI3K/Akt/survivin to sustain SERCA2a expression and activity to reduce SR-Ca2+-XO-mediated oxidative stress apoptosis.