Abstract 15303: The SGLT2 Inhibitor Canagliflozin Attenuates Fibrosis and Mitochondrial Dysfunction Induced by Hyperglycemia in Isolated Primary Human Cardiac Fibroblasts

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have been recently approved as antidiabetic drugs showing beneficial effects on major adverse cardiac events. The exact mechanisms underlying the favorable cardiac actions are mostly unknown. Methods: Human cardiac fibroblasts (HCFs) were cultured in 5mM glucose (normal glucose; NG), 30mM glucose (high glucose; HG) or 30mM with 1μM SGLT2is empagliflozin (EMPA), dapagliflozin (DAPA), canagliflozin (CANA), and ertugliflozin (ERTU)-containing medium for 24h. RNA-sequencing, Western blots, proliferation rate, Ca 2+ imaging, mitochondrial reactive oxygen species (ROS) were performed on HCFs. Results: HG induced a greater mitochondrial ROS production compared to NG, which was attenuated by SGLT2is. Specifically, we observed less ROS in the CANA group in comparison to EMPA, DAPA, and ERTU. In addition, sodium-hydrogen exchanger-1 (NHE-1) was upregulated in HG and such upregulation was markedly mitigated by SGLT2is, particularly by the CANA. Therefore, we continued other experiments using CANA. RNA-sequencing data revealed a clear segregation between HG and HG plus CANA. Strikingly, we observed upregulation of some genes (including NEAT1 , RNY1 related to cardiac fibrosis) in the HG group, which were downregulated in HG plus CANA. CANA significantly reduced proliferation rate compared to NG and HG. Compared to NG, HG significantly increased expression of Collagen I, Smad-2, mitochondrial fission (DRP-1) protein, and Beclin 1 (autophagy marker) which were instead reduced with CANA. Moreover, CANA upregulated mitochondrial fusion (MFN-1) protein. We assessed the difference in Ca 2+ flux in HCFs: HG decreased the capacity of the endoplasmic reticulum (ER) to accumulate Ca 2+ and delayed storage-operated Ca 2+ entry (SOCE); treatment with CANA partially prevented loss of ER Ca 2+ storage capacity and significantly improved SOCE timing. Conclusion: Our data indicate that CANA attenuates fibrosis, autophagy and mitochondrial dysfunction in HCFs in HG conditions and that this effect might be mediated through NHE-1 inhibition.