69-LB: Sex-Specific Dynamics of GLP-1R and GIPR Expression in the Hypothalamus and the Amygdala of Mice

Abstract

GIPR:GLP-1R co-agonism improves obesity and cardio-metabolic disease with superior efficacy in both male and female mice compared to mono-agonism. We detected sex-specific differences in metabolic phenotypes, which may point to differing sensitivity for GLP-1R and/or GIPR in areas of the hypothalamus regulating energy balance (ARC, VMH, DMH) and in areas of the amygdala regulating cardiovascular functions. To optimize future therapeutic benefits and minimize side effects from a perspective of sex differences, we investigated whether GLP1R and GIPR expression levels in specific cell populations of the hypothalamus and the amygdala regions are co-determined by sex and diet. Female and male C57Bl6 mice were fed normal chow or 58% high fat diet (HFD) for 21 days (n = 4, total mouse number 16). Spatial transcriptomics by in-situ hybridization method RNAscope™ was combined with immunofluorescence staining for neurons (NeuN), astrocytes (GFAP) and microglia (iba1) to identify cell type specific gene expression patterns of GLP1R and GIPR in female and male brains. In the hypothalamus, both sexes, gene expression of GLP-1R was higher compared to GIPR (ARC, VMH and DMH). In our studies GLP-1R and GIPR were mostly expressed in neurons, marginally in microglia and not observed in astrocytes in both sexes. HFD exposure reduced GLP-1R and GIPR gene expression in males only. In the Amygdala, neuronal GIPR gene expression levels were higher compared to GLP-1R in both sexes. HFD reduced GIPR and GLP-1R gene expression in males only. In females, HFD induced a slight increase of GIPR gene expression specifically in the central and basolateral amygdala. Our results reveal sex-specific dynamics in GLP-1R and GIPR expression patterns in metabolically relevant areas of the hypothalamus and the amygdala induced by HFD exposure. This may imply sex-specific dosing regimens of GIP:GLP-1R co-agonists for future treatments of cardio-metabolic disease Disclosure S. M. Hofmann: None. S. Zhang: None. R. Tom: None. T. D. Müller: Research Support; Novo Nordisk A/S, Speaker's Bureau; Eli Lilly and Company, AstraZeneca, Mercodia AB, Stock/Shareholder; Novo Nordisk A/S, Eli Lilly and Company. M. H. Tschöp: Consultant; Boehringer Ingelheim Pharma GmbH&Co. KG.