Abstract 633: Lack of ACE2 Abolishes High Fat Diet-Induced Upregulation of Prolyl Carboxypeptidase

Abstract

Emerging evidence suggests that activation of the proteases, Ang converting enzyme 2 (ACE2) and prolyl carboxypeptidase (PCP), are associated with metabolic pathologies. We hypothesized that global loss of ACE2 affects high fat diet induced renal expression of PCP. ACE2 knockout (ACE2KO) and wild type (WT) male mice were fed a 60% high fat (HF) or normal chow (NC) diet for 12 weeks. Using dual immunofluorescence microscopy and western blotting, we determined the expression pattern and abundance of ACE2 and PCP in kidney. PCP was co-localized with ACE2 in the Bowman’s capsule of the glomerulus. PCP was also localized along the apical membrane of proximal tubules along with ACE2. There was no evidence for protease co-localization in the tubules. ACE2 was absent in kidney from ACE2KO (immunofluorescence or western). PCP localization was unchanged in ACE2KO and the localization of both proteases did not change in response to HF diet. Protein intensity, normalized to ß-actin, showed no difference in PCP between untreated WT and KO (0.76±0.18 vs 0.57±0.07). PCP in HF WT was significantly elevated as compared to HF KO (0.94±0.02 vs 0.57±0.03, p≤0.05) while HF WT ACE2 levels remained unchanged as compared to untreated WT (0.90±0.24 vs 0.94±0.16). Results indicate loss of ACE2 negatively affects HF diet-induced PCP expression. Neither the absence of ACE2 nor HF diet changed the localization of PCP. These results suggest interactions between ACE2 and PCP in metabolic pathologies.