Abstract 43: PAR1 Inhibition with Vorapaxar Enhances Renal Function and Modulates Inflammation Mediators in Diabetic Nephropathy

Abstract

Diabetic nephropathy (DN) is the leading cause of end-stage renal failure, and hypertension is a comorbidity in about 90% of all cases. Characteristics of pathological changes of DN include severe albuminuria, renal hyperfiltration, glomerular basement membrane thickening, and glomerulosclerosis. Identifying the molecular mechanisms underlying DN is critical for developing more effective therapeutic approaches. Thus, interventions targeting podocytes have become a major focus for diseases like DN due to their crucial role in regulating glomerular permeability and maintaining glomerular structures. Our previous studies have demonstrated that serine proteases and Protease-activated receptor 1 (PAR1) are involved in developing DN through TRPC6-mediated calcium signaling in podocytes. Utilizing a PAR1 heterozygous knockout rat model with a type 2 diabetic background, we showed that reducing PAR1 expression decreases microalbuminuria and glomerular damage. This study aims to define the effects and potential mechanisms of pharmacological blockade of PAR1 on the development of DN. To achieve this, 16-week-old T2DN rats were treated with a potent and selective PAR1 antagonist (vorapaxar (SCH 530348), 10 mg/kg of diet) for 16 weeks to determine the effect of PAR1 inhibition. We found improvements in glomerular filtration rate (GFR) in treated animals compared to control after 16 weeks of treatment (0.8 ± 0.2 vs 1.2 ± 0.2 mL/min/100g b.w., p=0.029, N≥4). We observed a trend toward differences in basal intracellular calcium concentration in podocytes between the control and treated groups, although these changes were not statistically significant (202 ± 95 vs 152 ± 75 nM, p=0.19, n≥10, N=3). Additionally, inhibition of PAR1 caused modulation in the inflammation-resolution mediators in the kidney with significant upregulation of Maresins Conjugates in Tissue Regeneration (MCTR1) and downregulation of hydroxy-docosahexaenoic acids (7-,14-,17-HDHA). Changes in GFR may be linked to reduced glomerular damage, indicating that the structural integrity of the glomeruli is better maintained in treated animals. Alterations in the lipidomic profile could indicate a reduction in the inflammatory processes typically associated with DN. Overall, our data indicates that vorapaxar improves glomerular filtration rate and modulates lipid mediators in a type 2 diabetic rat model. This suggests that targeting PAR1 could be a promising therapeutic strategy for diabetic nephropathy.