Background: Several new treatments have recently been shown to have heart and kidney protective benefits in people with diabetes. Because these treatments were developed in parallel, it is unclear how the different molecular pathways affected by the therapies may overlap. Here, we examined the effects of the mineralocorticoid receptor antagonist finerenone in mice with comorbid diabetes, focusing on the regulation of expression of the glucagon-like peptide-1 receptor (GLP-1R), gastric inhibitory polypeptide receptor (GIPR) and glucagon receptor (GCGR), which are targets of approved or investigational therapies in diabetes.
Methods: Male C57BL/6J mice were fed a high fat diet for 26 weeks. Twelve weeks into the high fat diet feeding period, mice received an intraperitoneal injection of streptozotocin before being followed for the remaining 14 weeks (DMHFD mice). After 26 weeks, mice were fed a high fat diet containing finerenone (100 mg/kg diet) or high fat diet alone for a further 2 weeks. Cell culture experiments were performed in primary vascular smooth muscle cells (VSMCs), NRK-49 F fibroblasts, HK-2 cells, and MDCK cells.
Results: DMHFD mice developed albuminuria, glomerular mesangial expansion, and diastolic dysfunction (decreased E/A ratio). Glp1r and Gcgr were predominantly expressed in arteriolar VSMCs and distal nephron structures of mouse kidneys respectively, whereas Gipr was the predominant of the three transcripts in mouse hearts. Kidney Glp1r and Gcgr and cardiac Gipr mRNA levels were reduced in DMHFD mice and this reduction was negated or attenuated with finerenone. Mechanistically, finerenone attenuated upregulation of the profibrotic growth factor Ccn2 in DMHFD kidneys, whereas recombinant CCN2 downregulated Glp1r and Gcgr in VSMCs and MDCK cells respectively.
Conclusions: Through its anti-fibrotic actions, finerenone reverses Glp1r and Gcgr downregulation in the diabetic kidney. Both finerenone and GLP-1R agonists have proven cardiorenal benefits, whereas receptor co-agonists are approved or under development. The current findings provide preclinical rationale for the combined use of finerenone with the GLP-1R agonist family. They also provide mechanism of action insights into the potential benefit of finerenone in people with diabetes for whom GLP-1R agonists or co-agonists may not be indicated.
Keywords: CCN2; CTGF; Diabetic nephropathy; Finerenone; GLP-1; GLP-1 receptor; Gastric inhibitory polypeptide; Glucagon; Glucagon receptor; Mineralocorticoid receptor.
© 2024. The Author(s).