Molecular Mechanisms Linking Empagliflozin to Renal Protection in the LLC-PK1 Model of Diabetic Nephropathy
Vjera Mihaljević,
Milorad Zjalić,
Tomislav Kizivat,
Tea Omanović Kolarić,
Martina Smolić,
Edi Rođak,
Marina Čović,
Lucija Kuna,
Robert Smolić,
Aleksandar Včev,
Ines Bilić Ćurčić
Affiliations
Vjera Mihaljević
Department of Pharmacology and Biochemistry, Faculty of Dental Medicine and Health Osijek, University of J. J. Strossmayer Osijek, Crkvena 21, 31000 Osijek, Croatia
Milorad Zjalić
Department of Molecular Medicine and Biotechnology, Faculty of Medicine Rijeka, University of Rijeka, B. Branchetta 20, 51000 Rijeka, Croatia
Tomislav Kizivat
Department of Nuclear Medicine and Oncology, Faculty of Medicine Osijek, University of J. J. Strossmayer Osijek, J. Huttlera 4, 31000 Osijek, Croatia
Tea Omanović Kolarić
Department of Pharmacology and Biochemistry, Faculty of Dental Medicine and Health Osijek, University of J. J. Strossmayer Osijek, Crkvena 21, 31000 Osijek, Croatia
Martina Smolić
Department of Pharmacology and Biochemistry, Faculty of Dental Medicine and Health Osijek, University of J. J. Strossmayer Osijek, Crkvena 21, 31000 Osijek, Croatia
Edi Rođak
Department of Histology and Embryology, Faculty of Medicine Osijek, University of J. J. Strossmayer Osijek, J. Huttlera 4, 31000 Osijek, Croatia
Marina Čović
Family Medical Practice “Vedrana Ćosić, MD”, Osijek Health Center, Park kralja Petra Krešimira IV 6, 31000 Osijek, Croatia
Lucija Kuna
Department of Pharmacology and Biochemistry, Faculty of Dental Medicine and Health Osijek, University of J. J. Strossmayer Osijek, Crkvena 21, 31000 Osijek, Croatia
Robert Smolić
Department of Pharmacology and Biochemistry, Faculty of Dental Medicine and Health Osijek, University of J. J. Strossmayer Osijek, Crkvena 21, 31000 Osijek, Croatia
Aleksandar Včev
Department of Pathophysiology and Physiology with Immunology, Faculty of Dental Medicine and Health Osijek, University of J. J. Strossmayer Osijek, Crkvena 21, 31000 Osijek, Croatia
Ines Bilić Ćurčić
Department of Pharmacology, Faculty of Medicine, University of J. J. Strossmayer Osijek, J. Huttlera 4, 31000 Osijek, Croatia
Aims: Chronic diabetes complications, including diabetic nephropathy (DN), frequently result in end-stage renal failure. This study investigated empagliflozin (SGLT2i) effects on collagen synthesis, oxidative stress, cell survival, and protein expression in an LLC-PK1 model of DN. Methods: Combinations of high glucose (HG) and increasing empagliflozin concentrations (100 nM and 500 nM), as well as combinations of HG, H2O2, and empagliflozin, were used for cell culture treatment. The cell viability, glutathione (tGSH), ECM expression, and TGF-β1 concentration were measured. In addition, the protein expression of Akt, pAkt, GSK3, pGSK3, pSTAT3, and SMAD7 was determined. Results: The addition of both concentrations of empagliflozin to cells previously exposed to glucose and oxidative stress generally improved cell viability and increased GSH levels (p 0.001, p 2O2/Empa500-treated cells, significant increase in pSTAT3, pGSK3β, GSK3β, SMAD7, and pAKT levels (p 0.001, p 0.001, p 2O2-injured cells led to a decrease in TGF-β1 levels (p 0.001). In cells exposed to oxidative stress and hyperglycemia, collagen production remained unchanged. Conclusion: Renoprotective effects of empagliflozin, in this LLC-PK1 cell model of DN, are mediated via activation of the Akt/GSK-3 signalling pathway, thus reducing oxidative stress-induced damage, as well as enhanced SMAD7 expression leading to downregulation of TGF-β1, one of the key mediators of inflammation and fibrosis.
