9210 Nephron specific ATP6AP2 knockout reduces renal fat accumulation in mice consuming high fat diet

Abstract

Abstract Disclosure: S.A. Culver: None. J. Balugo: None. M. Jansen: None. T. Harris: None. H.M. Siragy: None. Diet induced obesity causes increased renal fat accumulation in both humans and mice which contributes to obesity related kidney injury. We have previously shown that mice with nephron specific ATP6AP2 knockout (KO) consuming high fat diet (HFD) are resistant to weight gain due to increased urinary excretion of glucose, albumin, and fatty acids. Magnetic resonance imaging (MRI) is a useful imaging modality for quantifying organ fat content in live animals though there are few reports of its use quantifying fat in murine kidney. We hypothesized that nephron specific ATP6AP2 knockout inhibits renal fat accumulation with HFD and that we would be able to detect this using MRI. Eight-week-old male wild type (WT) or inducible nephron specific ATP6AP2 KO mice underwent either induction with oral doxycycline or received sucrose water as controls before being placed on either normal diet (ND) (12% fat) or HFD (45% fat) for 3 months. Mice were then imaged using a 9.4 Tesla Bruker BioSpin MRI to determine both liver and kidney cortex fat content. The mean weight of WT HFD mice was 36.03 g compared to 29.03 g in WT ND controls. ND fed and HFD fed KO mice weighed 22.74 g and 23.03 g respectively. MRI showed significant 67% (p<0.05) increase in liver fat content in WT HFD compared to WT ND fed controls, confirming the ability of our MRI technique to detect expected differences in organ fat content. In renal cortex, MRI detected a 54% (p<0.05) increase in lipid content for WT HFD mice compared to WT ND controls. Nephron specific ATP6AP2 KO on HFD demonstrated reduced renal cortical lipid content by 36% (p<0.05) compared to WT HFD controls. These results indicate that ATP6AP2 KO is associated with reduced renal fat accumulation that is measurable with in vivo MRI. MRI therefore represents a valuable tool for studying renal sequelae of obesity in live murine models. Future investigation should examine whether ATP6AP2 KO prevents renal lipotoxicity and kidney injury in the setting of obesity. Presentation: 6/3/2024