Obesity reduces transcriptomic differences between the mesenteric arteries and adipose arterial endothelium
Authors: Dunaway Luke , Luse Melissa , Nyshadham Shruthi , Chavkin Nick , Isakson Brant 
Published: May 2023

It is well recognized that obesity leads to arterial endothelial dysfunction and cardiovascular disease. However, the etiology of the progression to endothelial dysfunction in arterial endothelium is not clear. Endothelial cells (ECs) adapt to the unique needs of their resident tissue and respond to systemic metabolic perturbations. We sought to better understand how obesity, modeled with a 12-week high fat diet (HFD; 60% fat), affects EC phenotypes in different tissues. We focused on adipose endothelium because of its proximity to adipocytes, and mesenteric endothelium for its proximity to lipid absorption and role in regulating peripheral resistance. Because of the mesenteric adipose deposition in HFD fed mice, we hypothesized mesenteric and adipose ECs would become phenotypically similar in HFD fed. In order to test this hypothesis, we performed single cell RNA sequencing on flow sorted ECs from normal chow (NC) and HFD endothelial YFP reporter mice. Mesentery and epididymal adipose tissue were collected, and YFP+ ECs were flow sorted and processed through the 10X Genomics platform. Data from two biological replicates were integrated for analysis. EC subtypes were identified based on known markers. We analyzed mesenteric and adipose endothelial populations from NC and HFD fed mice for differentially expressed genes (DEGs). We found HFD decreased the number of DEGs in all EC subtypes, but the largest effect was seen in arterial ECs. Further analysis of arterial ECs revealed genes coding for mitochondrial complex I-V proteins and lipid handling proteins were higher in adipose than mesentery under normal feeding but decreased in adipose of HFD mice to become similar to mesenteric ECs. We further analyzed transcriptional pathways (regulons) in arterial ECs using the SCENIC algorithm and generated regulon specificity scores (RSS) which reflect the specificity of regulons for each group. CEBPA and PPARγ, transcription factors known to regulate lipid handling and metabolism, had the highest RSS in the NC adipose artery ECs. Both regulons had lower RSS in mesenteric ECs and HFD adipose ECs. We further analyzed artery ECs from published human adipose single cell data (PMID: 35296864). Individuals were grouped into three groups based on body mass index (BMI; 20-30, 30-40, or 40-50). We found the lowest BMI group had higher PPARγ and CEBPA expression and RSS compared to the higher BMI groups. These data suggest mesenteric and adipose arterial ECs metabolize lipids differently and the phenotype of these two vascular beds converges in obesity, in part, due to downregulation of PPARγ and CEBPA in adipose artery ECs. This work lays the foundation for investigating vascular bed specific adaptations to obesity. University of Virginia Basic and Translational Research Training Grant T32 007284; LaunchPad; Lipedema Foundation This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.