Browsing by Author "Asghari, Arvand"
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Item Brown Adipose Tissue and 27-Hydroxycholesterol: An Energy Expenditure and Morphology Study of Brown Adipose Tissue(2021-04-01) Stephen, Robert; Asghari, Arvand; Bui, Linh; Dao, KevinBrown adipose tissue (BAT) is crucial for metabolism, body temperature regulation, and energy homeostasis. Recent studies on the first identified endogenous selective estrogen receptor modulator, 27-Hydroxycholesterol (27-HC), have suggested a link between BAT and 27-HC. 27-HC treatment with a high fat high cholesterol (HF/HC) diet increases white adipose tissue weight gain. Moreover, mouse models have suggested a decrease in dark cycle activity for mice treated with 27-HC and the HF/HC diet. These results suggest that BAT tissue undergoes morphological changes that result in the increase in white adipose tissue and decrease in activity. In this study, we further analyzed the morphological and energy expenditure changes that BAT undergoes in the presence of 27-HC and high fat high cholesterol diets. We observed a decrease in BAT vascularization, decreased energy expenditure, and increased inflammation. Our qPCR analysis revealed a decrease in BAT marker gene expression. Our results suggest that BAT undergoes significant morphological changes that transform it into a white adipose tissue like state. Further study of 27-HC’s effect on BAT is critical to understanding metabolic diseases such as obesity.Item Impact of 27-Hydrocholesterol on Brown Adipose Tissue at the Single Cell Level(2020-09-29) Bui, Linh; Asghari, Arvand27-Hydroxycholesterol (27HC), the most abundant oxysterol in circulation, is produced from cholesterol by CYP27A1 enzyme, and is catabolized by CYP7B1 enzyme. In addition, previously we found that 27HC is an endogenous selective estrogen receptor modulator (SERM), which links cholesterol metabolism to estrogen receptor actions. Brown adipose tissue is the primary source of energy expenditure and energy homeostasis, as well as body temperature maintenance. While previously it was believed that BAT activity is limited to neonates and young children, it is now recognized that BAT is also active in adult humans and its function is impaired by metabolic diseases such as obesity. BAT is also a secretory organ and produces brown adipokines, although the exact function of BAT and adipokines from this tissue in obesity has not been completely understood. To examine the effect of 27HC on cellular diversity and gene expression in the BAT, we propose to use the single cell RNA-seq (scRNA-seq) approach to first identify the different cell populations in BAT and their gene expression patterns, then to compare the changes in cell diversity and gene expressions upon elevated 27HC levels using 27HC-catabolizing enzyme Cyp7b1-/- mice. Currently, there is no available scRNA-seq dataset from BAT except for that using brown adipocyte only. Therefore, our proposed study will provide a fundamental resource for BAT biology, and also enables us to identify the cells responsible for the 27HC action in BAT and explore the changes in BAT following 27HC up-regulation, all for the first time.Item Interaction between Liver X Receptor Beta and Estrogen Receptor Alpha Variants in vitro(2019) Le, Rosemarie; Wu, Jacky; Rezaei, Hengameh; Asghari, ArvandThis project tests the interaction between the protein Liver X Receptor beta (LXR-beta) and variants of Estrogen Receptor alpha (ER-alpha) proteins in the presence of different ligands. The plasmids were modified in the lab and proteins were made from these plasmids using the coupled transcription/translation system. The techniques used were Co-Immunoprecipitation and Western Blot. The result shows interesting and unexpected interactions between LXR-beta and ER-alpha variants. More study is needed to measure the specific affinity of LXR-beta to each ER-alpha variant and the effect of these complexes.