P0710dual Gpr40/Gpr84 Fatty Acid Receptor Deletion Improves Adenine-Induced Renal Injury in Mice

Abstract

Background and Aims Fatty acid receptors have recently been implicated in the progression of fibrotic disorders. GPR40 deletion predisposes to AKI and CKD-induced fibrosis, while deletion of the pro-inflammatory GPR84 receptor was beneficial in this context. PBI-4050, a novel therapeutic compound with excellent safety and efficacy profiles in both experimental and clinical settings, is a dual GPR40 agonist and GPR84 antagonist. In this study, we sought to determine which of these receptors had a predominant effect in adenine-induced CKD. Method Ten-week-old male GPR40/84 double knockout mice (40/84ko) and age/strain matched WT C57BL/6 mice were subjected to a regular or adenine-supplemented diet (0.25%) for 4 weeks (n=10 per group). Plasma samples were collected on a weekly basis for hematocrit assessment. At endpoint, mice were placed in metabolic cages for 24 hours for urine collection. Plasma minerals and electrolytes, urinalysis and a comprehensive blood count were performed at endpoint. Results Adenine feeding led to early and sustained weight-loss, which was significantly worse in WT mice compared to 40/84ko mice. At day 14, Hct was significantly decreased in adenine-fed WT mice, while unaffected in the 40/84ko group. Adenine-induced reductions in hemoglobin and red blood cells counts were also greatly improved in 40/84ko mice. Adenine-feeding led to increased circulating neutrophils and decreased lymphocyte in WT mice, which was not seen in 40/84ko mice. Importantly, renal function assessed by plasma creatinine, urea and creatinine-clearance and renal hypertrophy were significantly improved in Ad-fed 40/84ko mice. Moreover, fractional excretion for sodium, potassium and calcium were increased by adenine-feeding in WT, but not in 40/84ko mice. Conclusion Overall, the loss of both GPR40 and GPR84 led to major improvements in several key renal functional abnormalities associated with adenine-induced CKD including weight-loss, anemia and renal functional decline. These studies, along with our previous work highlight the potential of targeting fatty-acid GPCR’s, notably GPR84, for the treatment of inflammation/fibrosis related kidney diseases.