GLP-1 receptor agonists and podocyte senescence in diabetic kidney disease: structural pharmacology, mechanistic evidence, and multi-receptor agonism.

Diabetic kidney disease (DKD) is a major cause of chronic kidney disease and kidney failure worldwide. Podocyte senescence is increasingly recognized as a contributor to diabetic glomerular injury, but its importance in human DKD and its modulation by glucagon-like peptide-1 receptor agonists (GLP-1RAs) remain incompletely defined. GLP-1RAs provide clinically meaningful kidney protection beyond glucose lowering, yet the responsible cellular mechanisms remain unresolved. This review integrates inactive- and agonist-bound GLP-1R structures with pharmacological, podocyte, renal, and clinical evidence to distinguish established findings from mechanistic hypotheses. Structural studies define principles of ligand recognition, receptor activation, G-protein coupling, signaling bias, and trafficking but do not establish podocyte-specific signaling. Experimental studies suggest that GLP-1RA exposure may modulate inflammatory, oxidative, mitochondrial, autophagic, and cell-death pathways that intersect with senescence-associated processes; however, evidence ranges from direct podocyte observations to extrapolation from whole-kidney, other renal-cell, or non-renal systems, and GLP-1R dependence within podocytes remains unresolved. Multi-receptor agonists targeting GLP-1R, the glucose-dependent insulinotropic polypeptide receptor (GIPR), and the glucagon receptor (GCGR) show favorable kidney signals, but renal receptor-level synergy and direct anti-senescence effects remain unproven. FLOW established kidney protection with semaglutide in type 2 diabetes and chronic kidney disease, reducing the primary composite of major kidney disease events or cardiovascular death by 24%. Candidate urinary and circulating biomarkers remain exploratory rather than validated measures of podocyte senescence or GLP-1R target engagement. We propose testable genetic and translational strategies to determine whether podocyte-intrinsic GLP-1R signaling contributes to GLP-1RA-associated kidney protection.