(721.5) Early Life Stress Increases Lipid Storage in Female Mice Fed a High Fat Diet via MR Activation in Adipocytes

Poster Board Number: E155

Jacqueline Leachman (University of Kentucky), Cole Cincinelli (University of Kentucky), Mei Xu (University of Kentucky), Andrew Morris (University of Arkansas for Medical Sciences), Terry Hinds Jr. (University of Kentucky), Analia Loria (University of Kentucky)

We have previously shown that Maternal Separation and Early Weaning (MSEW), a mouse model of early life stress, exacerbates high fat diet (HF)-induced obesity only in female offspring. Obese female MSEW mice display increased circulating and adrenal-derived aldosterone and increased gWAT-derived corticosterone compared with controls (C). Mineralocorticoid receptor (MR) activation has been shown to be critical in the regulation of the differentiation process of pre-adipocytes into mature adipocytes and overall adipocyte homeostasis. The aim of this study was to determine the role of MR in the mechanism by which MSEW induces perigonadal hypertrophy in female mice fed a high fat diet (HF). MSEW and C mice were weaned onto a HF (60 % Kcal from fat). After 20 weeks, gonadal white adipose tissue (gWAT) was collected to conduct: 1) lipidomic analysis and markers of whitening, 2) collagenase digestion followed by magnetic activated cell sorting for isolation of preadipocytes for RNAseq, and 3) in vitro lipolysis assay. Another subset of mice was randomized to receive vehicle (50% Ora swift in water) or a MR blocker, spironolactone (Spiro, 100 mg/kg/day), for 2 weeks. Female MSEW mice showed increased adiposity along with reduced mitochondrial DNA density (0.81±0.09 and 1.08±0.07 mtDNA/gDNA, plt;0.05 MSEW vs. C, respectively). Also, female MSEW mice displayed an increase of over 20 triacyclglycerols TAG, including a 6-fold increase in 44:2/FA 18:2+NH4 (plt;0.05 vs. C). Isolated mature adipocyte RNAseq revealed a 10-fold downregulation of Aquaglycerolporin 3 (AQP3) in MSEW mice, a channel in adipocytes responsible for glycerol efflux (plt;0.05 vs. C). Western blot analysis confirmed this reduction (0.40±0.08 and 1.0±0.14 AQP3/HSP90 plt;0.05 MSEW vs. C, respectively). Spiro treatment induced a significant fat mass loss in obese MSEW females (-3.5±0.9 and -1.0±0.5 delta fat mass (%BW) plt;0.05 MSEW vs. C, respectively). Increased intracellular glycerol in vehicle-treated MSEW mice was reduced to levels comparable to controls after Spiro treatment (1.08±0.2 and 1.64±0.12 mg glycerol/mg tissue, plt;0.05 MSEW vs. C, respectively) while Spiro also decreased basal and stimulated released glycerol in MSEW mice (plt;0.05). There were no differences in plasma glycerol between groups. It has been shown that aldosterone modulates AQP3 expression via MR signaling; however, Spiro treatment did not modify AQP3 protein expression. Overall, this data suggests that MR may play a role in adipose tissue hypertrophy as displayed by MSEW mice by preventing glycerol release in favor of triglyceride formation and storage, suggesting a role for impaired lipolysis that is independent of reduced AQP3 protein expression in adipocyte hypertrophy displayed by obese female MSEW mice.

This study was supported by funds from the NIH National Heart, Lung, and Blood Institute R00 HL111354 and R01 HL135158 to ASL, R01 HL135158-S1 to JRL, and the pilot project from the University of Kentucky Center of Research in Obesity and Cardiovascular Disease COBRE P20 GM103527 to ASL.