Endocrine System Diseases Commons^™

Interfering With Lipid Metabolism Through Targeting Ces1 Sensitizes Hepatocellular Carcinoma For Chemotherapy, Gang Li, Xin Li, Iqbal Mahmud, Jazmin Ysaguirre, Baharan Fekry, Shuyue Wang, Bo Wei, Kristin L Eckel-Mahan, Philip L Lorenzi, Richard Lehner, Kai Sun

Faculty, Staff and Student Publications

Hepatocellular carcinoma (HCC) is the most common lethal form of liver cancer. Apart from surgical removal and transplantation, other treatments have not yet been well established for patients with HCC. In this study, we found that carboxylesterase 1 (CES1) is expressed at various levels in HCC. We further revealed that blockage of CES1 by pharmacological and genetical approaches leads to altered lipid profiles that are directly linked to impaired mitochondrial function. Mechanistically, lipidomic analyses indicated that lipid signaling molecules, including polyunsaturated fatty acids (PUFAs), which activate PPARα/γ, were dramatically reduced upon CES1 inhibition. As a result, the expression of SCD, …

Adar1 Deletion Causes Degeneration Of The Exocrine Pancreas Via Mavs-Dependent Interferon Signaling, Dhwani N Rupani, Fredrik I Thege, Vidhi Chandra, Hajar Rajaei, Robert W Cowan, Sonja M Wörmann, Olivereen Le Roux, Prerna Malaney, Sara L Manning, Jack Hashem, Jennifer Bailey-Lundberg, Andrew D Rhim, Florencia Mcallister

Faculty, Staff and Student Publications

Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA-binding protein that deaminates adenosine (A) to inosine (I). A-to-I editing alters post-transcriptional RNA processing, making ADAR1 a crucial regulator of gene expression. Consequently, Adar1 has been implicated in organogenesis. To determine the role of Adar1 in pancreatic development and homeostasis, we conditionally deleted Adar1 from the murine pancreas (Ptf1aCre/+; Adar1Fl/Fl). The resulting mice had stunted growth, likely due to malabsorption associated with exocrine pancreatic insufficiency. Analyses of pancreata revealed ductal cell expansion, heightened interferon-stimulated gene expression and an increased influx of immune cells. Concurrent deletion of Adar1 and Mavs, a …

Receptor-Interacting Protein 1 And 3 Kinase Activity Are Required For High-Fat Diet Induced Liver Injury In Mice, Xiaoqin Wu, Rakesh K Arya, Emily Huang, Megan R Mcmullen, Laura E Nagy

Faculty, Staff and Student Publications

BACKGROUND: The RIP1-RIP3-MLKL-mediated cell death pathway is associated with progression of non-alcohol-associated fatty liver/steatohepatitis (NAFL/NASH). Previous work identified a critical role for MLKL, the key effector regulating necroptosis, but not RIP3, in mediating high fat diet-induced liver injury in mice. RIP1 and RIP3 have active N-terminus kinase domains essential for activation of MLKL and subsequent necroptosis. However, little is known regarding domain-specific roles of RIP1/RIP3 kinase in liver diseases. Here, we hypothesized that RIP1/RIP3 kinase activity are required for the development of high fat diet-induced liver injury.

METHODS:Rip1K45A/K45A and Rip3K51A/K51A kinase-dead mice on a C57BL/6J background and their littermate …

Analysis Of Genome-Wide Knockout Mouse Database Identifies Candidate Ciliopathy Genes, Kendall Higgins, Bret A Moore, Zorana Berberovic, Hibret A Adissu, Mohammad Eskandarian, Ann M Flenniken, Andy Shao, Denise M Imai, Dave Clary, Louise Lanoue, Susan Newbigging, Lauryl M J Nutter, David J Adams, Fatima Bosch, Robert E Braun, Steve D M Brown, Mary E Dickinson, Michael Dobbie, Paul Flicek, Xiang Gao, Sanjeev Galande, Anne Grobler, Jason D Heaney, Yann Herault, Martin Hrabe De Angelis, Hsian-Jean Genie Chin, Fabio Mammano, Chuan Qin, Toshihiko Shiroishi, Radislav Sedlacek, J-K Seong, Ying Xu, Impc Consortium, K C Kent Lloyd, Colin Mckerlie, Ala Moshiri

Faculty, Staff and Students Publications

We searched a database of single-gene knockout (KO) mice produced by the International Mouse Phenotyping Consortium (IMPC) to identify candidate ciliopathy genes. We first screened for phenotypes in mouse lines with both ocular and renal or reproductive trait abnormalities. The STRING protein interaction tool was used to identify interactions between known cilia gene products and those encoded by the genes in individual knockout mouse strains in order to generate a list of "candidate ciliopathy genes." From this list, 32 genes encoded proteins predicted to interact with known ciliopathy proteins. Of these, 25 had no previously described roles in ciliary pathobiology. …

Anti-Diabetic Effects Of Glp1 Analogs Are Mediated By Thermogenic Interleukin-6 Signaling In Adipocytes, Absalon D Gutierrez, Zhanguo Gao, Vala Hamidi, Liang Zhu, Karla Bermudez Saint Andre, Kayla Riggs, Monika Ruscheinsky, Hongyu Wang, Yongmei Yu, Charles Miller, Hernan Vasquez, Heinrich Taegtmeyer, Mikhail G Kolonin

Faculty, Staff and Student Publications

Mechanisms underlying anti-diabetic effects of GLP1 analogs remain incompletely understood. We observed that in prediabetic humans exenatide treatment acutely induces interleukin-6 (IL-6) secretion by monocytes and IL-6 in systemic circulation. We hypothesized that GLP1 analogs signal through IL-6 in adipose tissue (AT) and used the mouse model to test if IL-6 receptor (IL-6R) signaling underlies the effects of the GLP1-IL-6 axis. We show that liraglutide transiently increases IL-6 in mouse circulation and IL-6R signaling in AT. Metronomic liraglutide treatment resulted in AT browning and thermogenesis linked with STAT3 activation. IL-6-blocking antibody treatment inhibited STAT3 activation in AT and suppressed liraglutide-induced …

Rna Binding Protein Rbm46 Regulates Mitotic-To-Meiotic Transition In Spermatogenesis, Baomei Qian, Yang Li, Ruoyu Yan, Shenglin Han, Zhiwen Bu, Jie Gong, Bangjin Zheng, Zihan Yuan, Sen Ren, Qing He, Jinwen Zhang, Chen Xu, Ruilin Wang, Zheng Sun, Mingyan Lin, Jian Zhou, Lan Ye

Faculty, Staff and Students Publications

Meiosis entry during spermatogenesis requires reprogramming from mitotic to meiotic gene expression profiles. Transcriptional regulation has been extensively studied in meiosis entry, but gain of function for master transcription factors is insufficient to down-regulate mitotic genes. RNA helicase YTHDC2 and its partner MEIOC emerge as essential posttranscriptional regulators of meiotic entry. However, it is unclear what governs the RNA binding specificity of YTHDC2/MEIOC. Here, we identified RNA binding protein RBM46 as a component of the YTHDC2/MEIOC complex. Testis-specific Rbm46 knockout in mice causes infertility with defective mitotic-to-meiotic transition, phenocopying global Ythdc2 or Meioc knockout. RBM46 binds to 3′ UTR of …

Immunotherapy For Type 1 Diabetes Mellitus By Adjuvant-Free Schistosoma Japonicum-Egg Tip-Loaded Asymmetric Microneedle Patch (Stamp), Haoming Huang, Dian Hu, Zhuo Chen, Jiarong Xu, Rengui Xu, Yusheng Gong, Zhengming Fang, Ting Wang, Wei Chen

Faculty, Staff and Student Publications

BACKGROUND: Type 1 diabetes mellitus (T1DM) is an autoimmune disease mediated by autoreactive T cells and dominated by Th1 response polarization. Insulin replacement therapy faces great challenges to this autoimmune disease, requiring highly frequent daily administration. Intriguingly, the progression of T1DM has proven to be prevented or attenuated by helminth infection or worm antigens for a relatively long term. However, the inevitable problems of low safety and poor compliance arise from infection with live worms or direct injection of antigens. Microneedles would be a promising candidate for local delivery of intact antigens, thus providing an opportunity for the clinical immunotherapy …

Calcium/Calmodulin-Dependent Protein Kinase Kinase 2 Regulates Hepatic Fuel Metabolism, Brittany A Stork, Adam Dean, Andrea R Ortiz, Pradip Saha, Nagireddy Putluri, Maricarmen D Planas-Silva, Iqbal Mahmud, Kimal Rajapakshe, Cristian Coarfa, Stefan Knapp, Philip L Lorenzi, Bruce E Kemp, Benjamin E Turk, John W Scott, Anthony R Means, Brian York

Faculty, Staff and Students Publications

OBJECTIVE: The liver is the primary internal metabolic organ that coordinates whole body energy homeostasis in response to feeding and fasting. Genetic ablation or pharmacological inhibition of calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) has been shown to significantly improve hepatic health and peripheral insulin sensitivity upon overnutrition with high fat diet. However, the precise molecular underpinnings that explain this metabolic protection have remained largely undefined.

METHODS: To characterize the role of CaMKK2 in hepatic metabolism, we developed and challenged liver-specific CaMKK2 knockout (CaMKK2

RESULTS: Consistent with previous findings, we show that hepatic CaMKK2 ablation significantly improves indices of peripheral insulin …

Regulation Of Age-Associated Insulin Resistance By Mt1-Mmp-Mediated Cleavage Of Insulin Receptor, Xuanming Guo, Pallavi Asthana, Susma Gurung, Shuo Zhang, Sheung Kin Ken Wong, Samane Fallah, Chi Fung Willis Chow, Sijia Che, Lixiang Zhai, Zening Wang, Xin Ge, Zhixin Jiang, Jiayan Wu, Yijing Zhang, Xiaoyu Wu, Keyang Xu, Cheng Yuan Lin, Hiu Yee Kwan, Aiping Lyu, Zhongjun Zhou, Zhao-Xiang Bian, Hoi Leong Xavier Wong

Faculty, Staff and Student Publications

Insulin sensitivity progressively declines with age. Currently, the mechanism underlying age-associated insulin resistance remains unknown. Here, we identify membrane-bound matrix metalloproteinase 14 (MT1-MMP/MMP14) as a central regulator of insulin sensitivity during ageing. Ageing promotes MMP14 activation in insulin-sensitive tissues, which cleaves Insulin Receptor to suppress insulin signaling. MT1-MMP inhibition restores Insulin Receptor expression, improving insulin sensitivity in aged mice. The cleavage of Insulin Receptor by MT1-MMP also contributes to obesity-induced insulin resistance and inhibition of MT1-MMP activities normalizes metabolic dysfunctions in diabetic mouse models. Conversely, overexpression of MT1-MMP in the liver reduces the level of Insulin Receptor, impairing hepatic insulin …

An Exercise-Inducible Metabolite That Suppresses Feeding And Obesity, Veronica L Li, Yang He, Kévin Contrepois, Hailan Liu, Joon T Kim, Amanda L Wiggenhorn, Julia T Tanzo, Alan Sheng-Hwa Tung, Xuchao Lyu, Peter-James H Zushin, Robert S Jansen, Basil Michael, Kang Yong Loh, Andrew C Yang, Christian S Carl, Christian T Voldstedlund, Wei Wei, Stephanie M Terrell, Benjamin C Moeller, Rick M Arthur, Gareth A Wallis, Koen Van De Wetering, Andreas Stahl, Bente Kiens, Erik A Richter, Steven M Banik, Michael P Snyder, Yong Xu, Jonathan Z Long

Children’s Nutrition Research Center Staff Publications

Exercise confers robust protection against obesity, type 2 diabetes, and other cardiometabolic diseases.1–5 However, the molecular and cellular mechanisms that mediate the metabolic benefits of physical activity remain unclear.6 Here we show that exercise stimulates production of Lac-Phe, a blood-borne signaling metabolite that suppresses feeding and obesity. Lac-Phe biosynthesis from lactate occurs in CNDP2+ cells including immune cells, epithelial cells, and mesenchymal stem cells localized to diverse organs. In diet-induced obese mice, pharmacological elevation of circulating Lac-Phe reduces food intake without affecting movement or energy expenditure. Chronic administration of Lac-Phe decreases adiposity and body weight and …

Constitutive Loss Of Dnmt3a Causes Morbid Obesity Through Misregulation Of Adipogenesis, Ayala Tovy, Jaime M Reyes, Linda Zhang, Yung-Hsin Huang, Carina Rosas, Alexes C Daquinag, Anna Guzman, Raghav Ramabadran, Chun-Wei Chen, Tianpeng Gu, Sinjini Gupta, Laura Ortinau, Dongsu Park, Aaron R Cox, Rachel E Rau, Sean M Hartig, Mikhail G Kolonin, Margaret A Goodell

Faculty, Staff and Students Publications

DNA Methyltransferase 3 A (DNMT3A) is an important facilitator of differentiation of both embryonic and hematopoietic stem cells. Heterozygous germline mutations in DNMT3A lead to Tatton-Brown-Rahman Syndrome (TBRS), characterized by obesity and excessive height. While DNMT3A is known to impact feeding behavior via the hypothalamus, here we investigated a role in adipocyte progenitors utilizing heterozygous knockout mice that recapitulate cardinal TBRS phenotypes. These mice become morbidly obese due to adipocyte enlargement and tissue expansion. Adipose tissue in these mice exhibited defects in preadipocyte maturation and precocious activation of inflammatory gene networks, including interleukin-6 signaling. Adipocyte progenitor cell lines lacking DNMT3A …

Mitochondrial Sirtuin-3 (Sirt3) Prevents Doxorubicin-Induced Dilated Cardiomyopathy By Modulating Protein Acetylation And Oxidative Stress, Mateusz M Tomczyk, Kyle G Cheung, Bo Xiang, Nahid Tamanna, Ana L Fonseca Teixeira, Prasoon Agarwal, Stephanie M Kereliuk, Victor Spicer, Ligen Lin, Jason Treberg, Qiang Tong, Vernon W Dolinsky

Faculty, Staff and Students Publications

BACKGROUND: High doses of doxorubicin put cancer patients at risk for developing dilated cardiomyopathy. Previously, we showed that doxorubicin treatment decreases SIRT3 (sirtuin 3), the main mitochondrial deacetylase and increases protein acetylation in rat cardiomyocytes. Here, we hypothesize that SIRT3 expression can attenuate doxorubicin induced dilated cardiomyopathy in vivo by preventing the acetylation of mitochondrial proteins.

METHODS: Nontransgenic, M3-SIRT3 (truncated SIRT3; short isoform), and M1-SIRT3 (full-length SIRT3; mitochondrial localized) transgenic mice were treated with doxorubicin for 4 weeks (8 mg/kg body weight per week). Echocardiography was performed to assess cardiac structure and function and validated by immunohistochemistry and immunofluorescence (n=4-10). …

Berberine Remodels Adipose Tissue To Attenuate Metabolic Disorders By Activating Sirtuin 3, Dan Li, Chao Yang, Jian-Zhong Zhu, Eduardo Lopez, Tian Zhang, Qiang Tong, Cheng Peng, Li-Gen Lin

Faculty, Staff and Students Publications

Adipose tissue remodelling is considered a critical pathophysiological hallmark of obesity and related metabolic diseases. Berberine (BBR), a natural isoquinoline alkaloid, has potent anti-hyperlipidaemic and anti-hyperglycaemic effects. This study aimed to explore the role of BBR in modulating adipose tissue remodelling and the underlying mechanisms. BBR protected high fat diet (HFD)-fed mice against adiposity, insulin resistance and hyperlipidemia. BBR alleviated adipose tissue inflammation and fibrosis by inhibiting macrophage infiltration, pro-inflammatory macrophage polarization and the abnormal deposition of extracellular matrix, and the effect was mediated by BBR directly binding and activating the deacetylase Sirtuin 3 (SIRT3) and suppressing the activation of …

The Role Of Palmitoleic Acid In Regulating Hepatic Gluconeogenesis Through Sirt3 In Obese Mice, Xin Guo, Xiaofan Jiang, Keyun Chen, Qijian Liang, Shixiu Zhang, Juan Zheng, Xiaomin Ma, Hongmei Jiang, Hao Wu, Qiang Tong

Faculty, Staff and Students Publications

Hepatic gluconeogenesis is a crucial process to maintain glucose level during starvation. However, unabated glucose production in diabetic patients is a major contributor to hyperglycemia. Palmitoleic acid is a monounsaturated fatty acid (16:1n7) that is available from dietary sources. Palmitoleic acid exhibits health beneficial effects on diabetes, insulin resistance, inflammation, and metabolic syndrome. However, the mechanism by which palmitoleate reduces blood glucose is still unclear. SIRT3 is a key metabolism-regulating NAD+-dependent protein deacetylase. It is known that fasting elevates the expression of SIRT3 in the liver and it regulates many aspects of liver’s response to nutrient deprivation, such as fatty …

Glynac (Glycine And N-Acetylcysteine) Supplementation In Mice Increases Length Of Life By Correcting Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Abnormalities In Mitophagy And Nutrient Sensing, And Genomic Damage, Premranjan Kumar, Ob W Osahon, Rajagopal V Sekhar

Faculty, Staff and Students Publications

Determinants of length of life are not well understood, and therefore increasing lifespan is a challenge. Cardinal theories of aging suggest that oxidative stress (OxS) and mitochondrial dysfunction contribute to the aging process, but it is unclear if they could also impact lifespan. Glutathione (GSH), the most abundant intracellular antioxidant, protects cells from OxS and is necessary for maintaining mitochondrial health, but GSH levels decline with aging. Based on published human studies where we found that supplementing glycine and N-acetylcysteine (GlyNAC) improved/corrected GSH deficiency, OxS and mitochondrial dysfunction, we hypothesized that GlyNAC supplementation could increase longevity. We tested our hypothesis …

Isoform-Specific Functions Of Pparγ In Gene Regulation And Metabolism, Wenxiang Hu, Chunjie Jiang, Mindy Kim, Yang Xiao, Hannah J Richter, Dongyin Guan, Kun Zhu, Brianna M Krusen, Arielle N Roberts, Jessica Miller, David J Steger, Mitchell A Lazar

Faculty, Staff and Students Publications

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that is a vital regulator of adipogenesis, insulin sensitivity, and lipid metabolism. Activation of PPARγ by antidiabetic thiazolidinediones (TZD) reverses insulin resistance but also leads to weight gain that limits the use of these drugs. There are two main PPARγ isoforms, but the specific functions of each are not established. Here we generated mouse lines in which endogenous PPARγ1 and PPARγ2 were epitope-tagged to interrogate isoform-specific genomic binding, and mice deficient in either PPARγ1 or PPARγ2 to assess isoform-specific gene regulation. Strikingly, although PPARγ1 and PPARγ2 contain identical DNA binding domains, …

Secretogranin Iii Stringently Regulates Pathological But Not Physiological Angiogenesis In Oxygen-Induced Retinopathy, Chang Dai, Prabuddha Waduge, Liyang Ji, Chengchi Huang, Ye He, Hong Tian, Elizabeth Zuniga-Sanchez, Amit Bhatt, Iok-Hou Pang, Guanfang Su, Keith A Webster, Wei Li

Faculty, Staff and Students Publications

Conventional angiogenic factors, such as vascular endothelial growth factor (VEGF), regulate both pathological and physiological angiogenesis indiscriminately, and their inhibitors may elicit adverse side effects. Secretogranin III (Scg3) was recently reported to be a diabetes-restricted VEGF-independent angiogenic factor, but the disease selectivity of Scg3 in retinopathy of prematurity (ROP), a retinal disease in preterm infants with concurrent pathological and physiological angiogenesis, was not defined. Here, using oxygen-induced retinopathy (OIR) mice, a surrogate model of ROP, we quantified an exclusive binding of Scg3 to diseased versus healthy developing neovessels that contrasted sharply with the ubiquitous binding of VEGF. Functional immunohistochemistry visualized …

Paraventricular Vitamin D Receptors Are Required For Glucose Tolerance In Males But Not Females, Jessie Beck, Silvania Da Silva Teixeira, Keisha Harrison, Gabrielle Phillips, Yanlin He, Stephanie Sisley

Faculty, Staff and Students Publications

When delivered directly into the brain, vitamin D, can improve glucose levels in male mice. Additionally, the loss of the vitamin D receptor (VDR) in male mice's paraventricular hypothalamus (PVH) results in impaired glucose tolerance. Data in humans shows that low vitamin D levels are detrimental to glucose homeostasis, an effect that may be more prominent in men. However, it is unknown if vitamin D action in the brain is required for normal glucose regulation in female mice. This study shows that in both viral and genetic models, male mice with obesity and PVH VDR loss have impaired glucose tolerance …

Adrenomedullin And Its Receptors Are Expressed In Mouse Pancreatic Β-Cells And Suppresses Insulin Synthesis And Secretion, Yuanlin Dong, Simone Hernandez Ruano, Akansha Mishra, Kathleen A Pennington, Chandrasekhar Yallampalli

Faculty, Staff and Students Publications

Gestational diabetes mellitus (GDM) is associated with defective pancreatic β-cell adaptation in pregnancy, but the underlying mechanism remains obscure. Our previous studies demonstrated that GDM women display increased plasma adrenomedullin (ADM) levels, and non-obese GDM mice show decreased serum concentrations of insulin and the number of β-cells in pancreas islets. The aims of this study is to examine if ADM and its receptors are expressed in female mouse pancreas, and if so, whether insulin secretion is regulated by ADM in mouse β-cell line, NIT-1 cells and isolated mouse pancreatic islets. Present study shows that ADM and its receptor components CRLR, …

In Silico Integrative Analysis Of Multi-Omics Reveals Regulatory Layers For Diurnal Gene Expression In Mouse Liver, Chunjie Jiang, Panpan Liu, Cam Mong La, Dongyin Guan

Faculty, Staff and Students Publications

Diurnal oscillation persists throughout the body and plays an essential role in maintaining physiological homeostasis. Disruption of diurnal rhythm contributes to many diseases including type 2 diabetes. The regulatory mechanism of the transcription-translation feedback loop (TTFL) of core clock genes is well-established, while a systematic study across all regulatory layers of gene expression, including gene transcription, RNA translation, and DNA binding protein (DBP) activities, is still lacking. We comprehensively bioinformatics analyzed the rhythmicity of gene transcription, mature RNA abundance, protein abundance and DBP activity using publicly available omic-datasets from mouse livers. We found that the core clock genes,

A Novel Model Of Gestational Diabetes: Acute High Fat High Sugar Diet Results In Insulin Resistance And Beta Cell Dysfunction During Pregnancy In Mice, Akansha Mishra, Simone Hernandez Ruano, Pradip K Saha, Kathleen A Pennington

Faculty, Staff and Students Publications

Gestational diabetes mellitus (GDM) affects 7–18% of all pregnancies. Despite its high prevalence, there is no widely accepted animal model. To address this, we recently developed a mouse model of GDM. The goal of this work was to further characterize this animal model by assessing insulin resistance and beta cell function. Mice were randomly assigned to either control (CD) or high fat, high sugar (HFHS) diet and mated 1 week later. At day 0 (day of mating) mice were fasted and intraperitoneal insulin tolerance tests (ipITT) were performed. Mice were then euthanized and pancreata were collected for histological analysis. Euglycemic …

Hypothalamic Steroid Receptor Coactivator-2 Regulates Adaptations To Fasting And Overnutrition, Yongjie Yang, Yanlin He, Hailan Liu, Wenjun Zhou, Chunmei Wang, Pingwen Xu, Xing Cai, Hesong Liu, Kaifan Yu, Zhou Pei, Ilirjana Hyseni, Makoto Fukuda, Qingchun Tong, Jianming Xu, Zheng Sun, Bert W O'Malley, Yong Xu

Faculty, Staff and Students Publications

The neuroendocrine system coordinates metabolic and behavioral adaptations to fasting, including reducing energy expenditure, promoting counterregulation, and suppressing satiation and anxiety to engage refeeding. Here, we show that steroid receptor coactivator-2 (SRC-2) in pro-opiomelanocortin (POMC) neurons is a key regulator of all these responses to fasting. POMC-specific deletion of SRC-2 enhances the basal excitability of POMC neurons; mutant mice fail to efficiently suppress energy expenditure during food deprivation. SRC-2 deficiency blunts electric responses of POMC neurons to glucose fluctuations, causing impaired counterregulation. When food becomes available, these mutant mice show insufficient refeeding associated with enhanced satiation and discoordination of anxiety …

Adipose Tissue Hyaluronan Production Improves Systemic Glucose Homeostasis And Primes Adipocytes For Cl 316,243-Stimulated Lipolysis, Yi Zhu, Na Li, Mingyang Huang, Mason Bartels, Sophie Dogné, Shangang Zhao, Xi Chen, Clair Crewe, Leon Straub, Lavanya Vishvanath, Zhuzhen Zhang, Mengle Shao, Yongjie Yang, Christy M Gliniak, Ruth Gordillo, Gordon I Smith, William L Holland, Rana K Gupta, Bingning Dong, Nathalie Caron, Yong Xu, Yucel Akgul, Samuel Klein, Philipp E Scherer

Faculty, Staff and Students Publications

Plasma hyaluronan (HA) increases systemically in type 2 diabetes (T2D) and the HA synthesis inhibitor, 4-Methylumbelliferone, has been proposed to treat the disease. However, HA is also implicated in normal physiology. Therefore, we generated a Hyaluronan Synthase 2 transgenic mouse line, driven by a tet-response element promoter to understand the role of HA in systemic metabolism. To our surprise, adipocyte-specific overproduction of HA leads to smaller adipocytes and protects mice from high-fat-high-sucrose-diet-induced obesity and glucose intolerance. Adipocytes also have more free glycerol that can be released upon beta3 adrenergic stimulation. Improvements in glucose tolerance were not linked to increased plasma …

Rap1 In The Vmh Regulates Glucose Homeostasis, Kentaro Kaneko, Hsiao-Yun Lin, Yukiko Fu, Pradip K Saha, Ana B De La Puente-Gomez, Yong Xu, Kousaku Ohinata, Peter Chen, Alexei Morozov, Makoto Fukuda

Faculty, Staff and Students Publications

The hypothalamus is a critical regulator of glucose metabolism and is capable of correcting diabetes conditions independently of an effect on energy balance. The small GTPase Rap1 in the forebrain is implicated in high-fat diet-induced (HFD-induced) obesity and glucose imbalance. Here, we report that increasing Rap1 activity selectively in the medial hypothalamus elevated blood glucose without increasing the body weight of HFD-fed mice. In contrast, decreasing hypothalamic Rap1 activity protected mice from diet-induced hyperglycemia but did not prevent weight gain. The remarkable glycemic effect of Rap1 was reproduced when Rap1 was specifically deleted in steroidogenic factor-1-positive (SF-1-positive) neurons in the …

Ube2i Deletion In Adipocytes Causes Lipoatrophy In Mice, Aaron R Cox, Natasha Chernis, Kang Ho Kim, Peter M Masschelin, Pradip K Saha, Shawn M Briley, Robert Sharp, Xin Li, Jessica B Felix, Zheng Sun, David D Moore, Stephanie A Pangas, Sean M Hartig

Faculty, Staff and Students Publications

OBJECTIVE: White adipose tissue (WAT) expansion regulates energy balance and overall metabolic homeostasis. The absence or loss of WAT occurring through lipodystrophy and lipoatrophy contributes to the development of hepatic steatosis and insulin resistance. We previously demonstrated that sole small ubiquitin-like modifier (SUMO) E2-conjugating enzyme Ube2i represses human adipocyte differentiation. The role of Ube2i during WAT development remains unknown.

METHODS: To determine how Ube2i impacts body composition and energy balance, we generated adipocyte-specific Ube2i knockout mice (Ube2i

RESULTS: Surprisingly, Ube2i

CONCLUSIONS: Our results demonstrate that Ube2i expression in mature adipocytes allows WAT expansion during postnatal growth. Deletion of Ube2i in …

Mitophagy Deficiency Increases Nlrp3 To Induce Brown Fat Dysfunction In Mice, Myoung Seok Ko, Ji Young Yun, In-Jeoung Baek, Jung Eun Jang, Jung Jin Hwang, Seung Eun Lee, Seung-Ho Heo, David A Bader, Chul-Ho Lee, Jaeseok Han, Jong-Seok Moon, Jae Man Lee, Eun-Gyoung Hong, In-Kyu Lee, Seong Who Kim, Joong Yeol Park, Sean M Hartig, Un Jung Kang, David D Moore, Eun Hee Koh, Ki-Up Lee

Faculty, Staff and Students Publications

Although macroautophagy/autophagy deficiency causes degenerative diseases, the deletion of essential autophagy genes in adipocytes paradoxically reduces body weight. Brown adipose tissue (BAT) plays an important role in body weight regulation and metabolic control. However, the key cellular mechanisms that maintain BAT function remain poorly understood. in this study, we showed that global or brown adipocyte-specific deletion of pink1, a Parkinson disease-related gene involved in selective mitochondrial autophagy (mitophagy), induced BAT dysfunction, and obesity-prone type in mice. Defective mitochondrial function is among the upstream signals that activate the NLRP3 inflammasome. NLRP3 was induced in brown adipocyte precursors (BAPs) from pink1 …

Rev-Erb In Gabaergic Neurons Controls Diurnal Hepatic Insulin Sensitivity, Guolian Ding, Xin Li, Xinguo Hou, Wenjun Zhou, Yingyun Gong, Fuqiang Liu, Yanlin He, Jia Song, Jing Wang, Paul Basil, Wenbo Li, Sichong Qian, Pradip Saha, Jinbang Wang, Chen Cui, Tingting Yang, Kexin Zou, Younghun Han, Christopher I Amos, Yong Xu, Li Chen, Zheng Sun

Faculty, Staff and Students Publications

Systemic insulin sensitivity shows diurnal rhythm with a peak at wakening1,2. The molecular mechanism underlying such a temporal pattern is unclear. Here we demonstrate that nuclear receptors Rev-erbα/β in the GABAergic neurons in the suprachiasmatic nucleus (SCNGABA) control the diurnal rhythm of insulin-mediated suppression of hepatic glucose production in mice, without affecting diurnal eating or locomotor behaviors under the regular light-dark cycles. Rev-erb regulates the rhythmic expression of genes involved in neurotransmission in the SCN and modulates the oscillatory firing activity of SCNGABA neurons. Chemogenetic stimulation of SCNGABA neurons at wakening causes glucose intolerance, while restoration …

Loss Of Bone Morphogenetic Protein-Binding Endothelial Regulator Causes Insulin Resistance, Hua Mao, Luge Li, Qiying Fan, Aude Angelini, Pradip K Saha, Huaizhu Wu, Christie M Ballantyne, Sean M Hartig, Liang Xie, Xinchun Pi

Faculty, Staff and Students Publications

Accumulating evidence suggests that chronic inflammation of metabolic tissues plays a causal role in obesity-induced insulin resistance. Yet, how specific endothelial factors impact metabolic tissues remains undefined. Bone morphogenetic protein (BMP)–binding endothelial regulator (BMPER) adapts endothelial cells to inflammatory stress in diverse organ microenvironments. Here, we demonstrate that BMPER is a driver of insulin sensitivity. Both global and endothelial cell-specific inducible knockout of BMPER cause hyperinsulinemia, glucose intolerance and insulin resistance without increasing inflammation in metabolic tissues in mice. BMPER can directly activate insulin signaling, which requires its internalization and interaction with Niemann-Pick C1 (NPC1), an integral membrane protein that …

The Bile Acid Induced Hepatokine Orosomucoid Suppresses Adipocyte Differentiation, Sung Ho Lee, Jong Min Choi, Sung Yun Jung, Aaron R Cox, Sean M Hartig, David D Moore, Kang Ho Kim

Faculty, Staff and Students Publications

Bile acids have recently emerged as key metabolic hormones with beneficial impacts in multiple metabolic diseases. We previously discovered that hepatic bile acid overload distally modulates glucose and fatty acid metabolism in adipose tissues to exert anti-obesity effects. However, the detailed mechanisms that explain the salutary effects of serum bile acid elevation remain unclear. Here, proteomic profiling identified a new hepatokine, Orosomucoid (ORM) that governs liver-adipose tissue crosstalk. Hepatic ORMs were highly induced by both genetic and dietary bile acid overload. To address the direct metabolic effects of ORM, purified ORM proteins were administered during adipogenic differentiation of 3T3-L1 cells …

Stat1 Dissociates Adipose Tissue Inflammation From Insulin Sensitivity In Obesity, Aaron R Cox, Natasha Chernis, David A Bader, Pradip K Saha, Peter M Masschelin, Jessica B Felix, Robert Sharp, Zeqin Lian, Vasanta Putluri, Kimal Rajapakshe, Kang Ho Kim, Dennis T Villareal, Reina Armamento-Villareal, Huaizhu Wu, Cristian Coarfa, Nagireddy Putluri, Sean M Hartig

Faculty, Staff and Students Publications

Obesity fosters low-grade inflammation in white adipose tissue (WAT) that may contribute to the insulin resistance that characterizes type 2 diabetes. However, the causal relationship of these events remains unclear. The established dominance of STAT1 function in the immune response suggests an obligate link between inflammation and the comorbidities of obesity. To this end, we sought to determine how STAT1 activity in white adipocytes affects insulin sensitivity. STAT1 expression in WAT inversely correlated with fasting plasma glucose in both obese mice and humans. Metabolomic and gene expression profiling established STAT1 deletion in adipocytes (STAT1a-KO) enhanced mitochondrial function …