27ヒドロキシコレステロールはエストロゲン受容体を介してヒトSLC22A12の発現を制御する

The excretion and reabsorption of uric acid both to and from urine are tightly regulated by uric acid transporters. Metabolic syndrome conditions, such as obesity, hypercholesterolemia, and insulin resistance, are believed to regulate the expression of uric acid transporters and decrease the excretion of uric acid. However, the mechanisms driving cholesterol impacts on uric acid transporters have been unknown. Here, we show that cholesterol metabolite 27-hydroxycholesterol (27HC) upregulates the uric acid reabsorption transporter URAT1 encoded by SLC22A12 via estrogen receptors (ER). Transcriptional motif analysis showed that the SLC22A12 gene promoter has more estrogen response elements (EREs) than other uric acid reabsorption transporters such as SLC22A11 and SLC22A13, and 27HC-activated SLC22A12 gene promoter via ER through EREs. Furthermore, 27HC increased SLC22A12 gene expression in human kidney organoids. Our results suggest that in hypercholesterolemic conditions, elevated levels of 27HC derived from cholesterol induce URAT1/SLC22A12 expression to increase uric acid reabsorption, and thereby, could increase serum uric acid levels.博士（医学）・甲第772号・令和3年3月15日© 2020 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License(https://creativecommons.org/licenses/by-nc/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes

An Investigation into the Role of 27-Hydroxycholesterol and Estrogen Receptors in Adipose Tissue, Obesity, and Breast Cancer

Obesity is an emerging health crisis all over the world. With obesity comes several other health disorders such as type-2 diabetes, cardiovascular diseases, and cancers. Hence, understanding the underlying reasons for obesity is of paramount importance as it can guide us in developing new therapeutic approaches for preventing or decreasing the obesity rates. Breast cancer is the second cause of cancer-related deaths among women worldwide. Endocrine resistance in breast cancer which occurs after endocrine therapies, causes the tumors to relapse after years of dormancy. While estrogen receptors (ERs) mutations and malfunctions of other signaling pathways (e.g., MAPK signaling) are some of the underlying reasons for endocrine resistance in breast cancer, the underlying causes of 60% of endocrine resistance cases remain completely unknown. Estrogen and estrogen receptors play important roles in both obesity and breast cancer. 27-Hydroxycholesterol (27HC), the first identified endogenous selective estrogen receptor modulator, can modulate the activity of estrogen receptors in different tissues and thus can be one of the important factors in regulating the functions of ERs in the context of obesity and breast cancer. In this dissertation, I first showed that 27HC mostly works as an antagonist for ERs activity in different tissues. Next, I investigated the effects of 27HC on adipose tissues and obesity. My research showed that 27HC increases body weight gain in the presence of a high-fat, high- cholesterol diet in an ER-dependent manner. Moreover, 27HC increases body fat percentage regardless of the diet and affects adipose tissue gene expression and induces inflammation in the adipose tissue. I also showed that 27HC alters the morphology and function of brown adipose tissue. In regard to endocrine resistance in breast cancer, I showed that 27HC increases the growth rate of the endocrine-resistant breast cancer cells, and I also found a novel group of genes that can be the underlying reasons for the endocrine development and progression. All in all, the research presented in this dissertation confirms the importance of 27HC in obesity and breast cancer and opens new doors toward the development of potential therapeutics to decrease the obesity rates, as well as treatment of endocrine-resistant breast cancer

Impact of 27-Hydrocholesterol on Brown Adipose Tissue at the Single Cell Level

27-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.Biology and Biochemistry, Department ofHonors Colleg

Brown Adipose Tissue and 27-Hydroxycholesterol: An Energy Expenditure and Morphology Study of Brown Adipose Tissue

Brown 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.Biology and Biochemistry, Department ofHonors Colleg

Interaction between Liver X Receptor Beta and Estrogen Receptor Alpha Variants in vitro

This 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.Biology and Biochemistry, Department ofHonors Colleg

A sperm-specific proteome-scale metabolic network model identifies non-glycolytic genes for energy deficiency in asthenozoospermia

<p>About 15% of couples experience difficulty in conceiving a child, of which half of the cases are thought to be male-related. Asthenozoospermia, or low sperm motility, is one of the frequent types of male infertility. Although energy metabolism is suggested to be central to the etiology of asthenozoospermia, very few attempts have been made to identify its underlying metabolic pathways. Here, we reconstructed SpermNet, the first proteome-scale model of the sperm cell by using whole-proteome data and the mCADRE algorithm. The reconstructed model was then analyzed using the COBRA toolbox. Genes were knocked-out in the model to investigate their effect on ATP production. A total of 78 genes elevated ATP production rate considerably of which most encode components of oxidative phosphorylation, fatty acid oxidation, the Krebs cycle, and members of the solute carrier 25 family. Among them, we identified 11 novel genes which have previously not been associated with sperm cell energy metabolism and may thus be implicated in asthenozoospermia. We further examined the reconstructed model by <i>in silico</i> knock out of currently known asthenozoospermia implicated-genes that were not predicted by our model. The pathways affected by knocking out these genes were also related to energy metabolism, confirming previous findings. Therefore, our model not only predicts the known pathways, it also identifies several non-glycolytic genes for deficient energy metabolism in asthenozoospermia. Finally, this model supports the notion that metabolic pathways besides glycolysis such as oxidative phosphorylation and fatty acid oxidation are essential for sperm energy metabolism and if validated, may form a basis for fertility recovery.</p> <p><b>Abbreviations</b>: mCADRE: metabolic context-specificity assessed by deterministic reaction evaluation; ATP: adenosine triphosphate; RNA: ribonucleic acid; FBA: flux balance analysis; FVA: flux variability analysis; DAVID: database for annotation, visualization and integrated discovery; OXPHOS: oxidative phosphorylation; ETC: electron transfer chain; SLC: solute carrier; DLD: dihydrolypoamide dehydrogenase; DLST: dihydrolypoamide S-succinyl transferase; OGDH: oxoglutarate dehydrogenase; CS: citrate synthase; FH: fumarate hydratase; IDH: isocitrate dehydrogenase; SUCLG1: succinate-CoA ligase; SD: succinate dehydrogenase; HADHA: hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase, subunit A; HADHB: hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase, subunit B; PPA2: pyrophosphatase (inorganic) 2; PP_i: inorganic phosphate; GALT: galactose-1-phosphate uridylyltransferase</p

Can scientific journals be classified based on their ‘citation profiles’?

Classification of scientific publications is of great importance in biomedical research evaluation. However, accurate classification of research publications is challenging and normally is performed in a rather subjective way. In the present paper, we propose to classify biomedical publications into superfamilies, by analysing their citation profiles, i.e. the location of citations in the structure of citing articles. Such a classification may help authors to find the appropriate biomedical journal for publication, may make journal comparisons more rational, and may even help planners to better track the consequences of their policies on biomedical research

Can scientific journals be classified based on their ‘citation profiles’?

Classification of scientific publications is of great importance in biomedical research evaluation. However, accurate classification of research publications is challenging and normally is performed in a rather subjective way. In the present paper, we propose to classify biomedical publications into superfamilies, by analysing their citation profiles, i.e. the location of citations in the structure of citing articles. Such a classification may help authors to find the appropriate biomedical journal for publication, may make journal comparisons more rational, and may even help planners to better track the consequences of their policies on biomedical research