Endocrine System Diseases Commons^™

Pancreatic Differentiation Of Stem Cells Reveals Pathogenesis Of A Syndrome Of Ketosis-Prone Diabetes, Diane Yang, Sanjeet Patel, Wojciech J Szlachcic, Jolanta Chmielowiec, Diane Scaduto, Nagireddy Putluri, Arun Sreekumar, James Suliburk, Michael Metzker, Ashok Balasubramanyam, Malgorzata Borowiak

Faculty, Staff and Students Publications

Genetic analysis of an adult patient with an unusual course of ketosis-prone diabetes (KPD) and lacking islet autoantibodies demonstrated a nucleotide variant in the 5′-untranslated region (UTR) of PDX1, a β-cell development gene. When differentiated to the pancreatic lineage, his induced pluripotent stem cells stalled at the definitive endoderm (DE) stage. Metabolomics analysis of the cells revealed that this was associated with leucine hypersensitivity during transition from the DE to the pancreatic progenitor (PP) stage, and RNA sequencing showed that defects in leucine-sensitive mTOR pathways contribute to the differentiation deficiency. CRISPR/Cas9 manipulation of the PDX1 variant demonstrated that it …

Hiv-1 Viral Protein R Couples Metabolic Inflexibility With White Adipose Tissue Thermogenesis, Neeti Agarwal, Dinakar Iyer, Pradip Saha, Aaron R Cox, Yan Xia, Netanya S Utay, Anoma Somasundaram, Ulrich Schubert, Jordan E Lake, Sean M Hartig, Ashok Balasubramanyam

Faculty, Staff and Students Publications

Persons living with HIV (PLWH) manifest chronic disorders of brown and white adipose tissues that lead to diabetes and metabolic syndrome. The mechanisms that link viral factors to defective adipose tissue function and abnormal energy balance in PLWH remain incompletely understood. Here, we explored how the HIV accessory protein viral protein R (Vpr) contributes to adaptive thermogenesis in two mouse models and human adipose tissues. Uncoupling protein 1 (UCP1) gene expression was strongly increased in subcutaneous white adipose tissue (WAT) biopsy specimens from PLWH and in subcutaneous WAT of the Vpr mice, with nearly equivalent mRNA copy number. Histology and …

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 …

Metabolomics Profiling Of Patients With A-Β+ Ketosis-Prone Diabetes During Diabetic Ketoacidosis, Farook Jahoor, Jean W Hsu, Paras B Mehta, Kelly R Keene, Ruchi Gaba, Surya Narayan Mulukutla, Eunice Caducoy, W Frank Peacock, Sanjeet G Patel, Rasmus Bennet, Ake Lernmark, Ashok Balasubramanyam

Faculty, Staff and Students Publications

When stable and near-normoglycemic, patients with “A−β+” ketosis-prone diabetes (KPD) manifest accelerated leucine catabolism and blunted ketone oxidation, which may underlie their proclivity to develop diabetic ketoacidosis (DKA). To understand metabolic derangements in A−β+ KPD patients during DKA, we compared serum metabolomics profiles of adults during acute hyperglycemic crises, without (n = 21) or with (n = 74) DKA, and healthy control subjects (n = 17). Based on 65 kDa GAD islet autoantibody status, C-peptide, and clinical features, 53 DKA patients were categorized as having KPD and 21 type 1 diabetes (T1D); 21 nonketotic patients were categorized as …

Neurovascular Regulation In Diabetic Retinopathy And Emerging Therapies, Liyang Ji, Hong Tian, Keith A Webster, Wei Li

Faculty, Staff and Students Publications

Diabetic retinopathy (DR) is the leading cause of vision loss in working adults in developed countries. The disease traditionally classified as a microvascular complication of diabetes is now widely recognized as a neurovascular disorder resulting from disruption of the retinal neurovascular unit (NVU). The NVU comprising retinal neurons, glia and vascular cells coordinately regulates blood flow, vascular density and permeability to maintain homeostasis. Disturbance of the NVU during DR can lead to vision-threatening clinical manifestations. A limited number of signaling pathways have been identified for intercellular communication within the NVU, including vascular endothelial growth factor (VEGF), the master switch for …

High Burden Of Subclinical And Cardiovascular Disease Risk In Adults With Metabolically Healthy Obesity: The Atherosclerosis Risk In Communities (Aric) Study, Yvonne Commodore-Mensah, Mariana Lazo, Olive Tang, Justin B Echouffo-Tcheugui, Chiadi E Ndumele, Vijay Nambi, Dan Wang, Christie Ballantyne, Elizabeth Selvin

Faculty, Staff and Students Publications

OBJECTIVE: It is controversial whether adults who are obese but "metabolically healthy" have cardiovascular disease (CVD) risk comparable with that of normal-weight adults. High-sensitivity cardiac troponin T (hs-cTnT), a biomarker of myocardial damage, is useful in characterizing subclinical CVD. We categorized obesity phenotypes and studied their associations with subclinical and clinical CVD and CVD subtypes, including heart failure (HF).

RESEARCH DESIGN AND METHODS: We conducted cross-sectional and prospective analyses of 9,477 adults in the Atherosclerosis Risk in Communities (ARIC) study. We used the Adult Treatment Panel III criteria and BMI to define obesity phenotypes as follows: metabolically healthy normal weight, …

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 …

Type 2 Diabetes Subgroups, Risk For Complications, And Differential Effects Due To An Intensive Lifestyle Intervention, Michael P Bancks, Haiying Chen, Ashok Balasubramanyam, Alain G Bertoni, Mark A Espeland, Steven E Kahn, Scott Pilla, Elizabeth Vaughan, Lynne E Wagenknecht

Faculty, Staff and Students Publications

OBJECTIVE: We reevaluated the Action for Health in Diabetes (Look AHEAD) intervention, incorporating diabetes subgroups, to identify whether intensive lifestyle intervention (ILI) is associated with differential risk for cardiovascular disease (CVD) by diabetes subgroup.

RESEARCH DESIGN AND METHODS: In the Look AHEAD trial, 5,145 participants, aged 45-76 years, with type 2 diabetes (T2D) and overweight or obesity were randomly assigned to 10 years of ILI or a control condition of diabetes support and education. The ILI focused on weight loss through decreased caloric intake and increased physical activity. To characterize diabetes subgroups, we applied k-means clustering to data on age …

Acetyl-Coa And Metabolite Fluxes Regulate White Adipose Tissue Expansion, Jessica B Felix, Aaron R Cox, Sean M Hartig

Faculty, Staff and Students Publications

White adipose tissue (WAT) depends on coordinated regulation of transcriptional and metabolic pathways to respond to whole-body energy demands. We highlight metabolites that contribute to biosynthetic reactions for WAT expansion. Recent studies have precisely defined how byproducts of carbohydrate and lipid metabolism affect physiological and endocrine functions in adipocytes. We emphasize the critical emerging roles of short-chain fatty acids (SCFAs) and tricarboxylic acid (TCA) cycle metabolites that connect lipogenesis to WAT energy balance and endocrine functions. These insights address how adipocytes use small molecules generated from central carbon metabolism to measure responses to nutritional stress.

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 …

In Men With Obesity, T2dm Is Associated With Poor Trabecular Microarchitecture And Bone Strength And Low Bone Turnover, Francesca Vigevano, Giulia Gregori, Georgia Colleluori, Rui Chen, Vimlin Autemrongsawat, Nicola Napoli, Clifford Qualls, Dennis T Villareal, Reina Armamento-Villareal

Faculty, Staff and Students Publications

INTRODUCTION: Obesity and type 2 Diabetes (T2D) are both associated with greater bone mineral density (BMD) but increased risk of fractures. The effect of the combination of both conditions on bone metabolism, microarchitecture, and strength in the obese population remains unknown.

METHODS: Data from 112 obese men were collected. Bone turnover and biochemical markers were measured by enzyme-linked immunosorbent assay, body composition and BMD at all sites were assessed by dual energy X-ray absorptiometry, whereas bone microarchitecture and strength (stiffness and failure load) were measured by high-resolution peripheral computed tomography. Data were compared among metabolically healthy obese (MHO) and metabolically …

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 …

Single-Cell Rna-Seq Analysis Reveals Compartment-Specific Heterogeneity And Plasticity Of Microglia, Junying Zheng, Wenjuan Ru, Jay R Adolacion, Michael S Spurgat, Xin Liu, Subo Yuan, Rommel X Liang, Jianli Dong, Andrew S Potter, S Steven Potter, Ken Chen, Rui Chen, Navin Varadarajan, Shao-Jun Tang

Faculty, Staff and Students Publications

Microglia are ubiquitous central nervous system (CNS)-resident macrophages that maintain homeostasis of neural tissues and protect them from pathogen attacks. Yet, their differentiation in different compartments remains elusive. We performed single-cell RNA-seq to compare microglial subtypes in the cortex and the spinal cord. A multi-way comparative analysis was carried out on samples from C57/BL and HIV gp120 transgenic mice at two, four, and eight months of age. The results revealed overlapping but distinct microglial populations in the cortex and the spinal cord. The differential heterogeneity of microglia in these CNS regions was further suggested by their disparity of plasticity in …

Testosterone Therapy And Bone Quality In Men With Diabetes And Hypogonadism: Study Design And Protocol, Vittoria Russo, Georgia Colleluori, Rui Chen, Sanjay Mediwala, Clifford Qualls, Michael Liebschner, Dennis T Villareal, Reina Armamento-Villareal

Faculty, Staff and Students Publications

CONTEXT: Type 2 diabetes mellitus (T2D) is often accompanied by male hypogonadism and both conditions are associated with increased risk for fractures. Testosterone (T) has been shown to improve the bone health of hypogonadal men but has not been tested in patients who also have T2D in addition to low T. To date, there is no treatment that is specifically recommended for bone disease among patients with T2D. This study will evaluate the effect of T therapy on the bone health of male veterans with low T who also have T2D.

METHODS: This is a randomized double-blind placebo-controlled trial of …

Addressing Artificial Intelligence Bias In Retinal Diagnostics, Philippe Burlina, Neil Joshi, William Paul, Katia D Pacheco, Neil M Bressler

Faculty, Staff and Students Publications

PURPOSE: This study evaluated generative methods to potentially mitigate artificial intelligence (AI) bias when diagnosing diabetic retinopathy (DR) resulting from training data imbalance or domain generalization, which occurs when deep learning systems (DLSs) face concepts at test/inference time they were not initially trained on.

METHODS: The public domain Kaggle EyePACS dataset (88,692 fundi and 44,346 individuals, originally diverse for ethnicity) was modified by adding clinician-annotated labels and constructing an artificial scenario of data imbalance and domain generalization by disallowing training (but not testing) exemplars for images of retinas with DR warranting referral (DR-referable) from darker-skin individuals, who presumably have greater …

Association Of Baseline Characteristics With Insulin Sensitivity And Β-Cell Function In The Glycemia Reduction Approaches In Diabetes: A Comparative Effectiveness (Grade) Study Cohort, Neda Rasouli, Naji Younes, Kristina M Utzschneider, Silvio E Inzucchi, Ashok Balasubramanyam, Andrea L Cherrington, Faramarz Ismail-Beigi, Robert M Cohen, Darin E Olson, Ralph A Defronzo, William H Herman, John M Lachin, Steven E Kahn, Grade Research Group

Faculty, Staff and Students Publications

OBJECTIVE: We investigated sex and racial differences in insulin sensitivity, β-cell function, and glycated hemoglobin (HbA

RESEARCH DESIGN AND METHODS: This is a cross-sectional analysis of baseline data from 3,108 GRADE (Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study) participants. All had type 2 diabetes diagnosedβ-cell function were evaluated using the HOMA of insulin sensitivity and estimates from oral glucose tolerance tests, including the Matsuda Index, insulinogenic index, C-peptide index, and oral disposition index (DI).

RESULTS: The cohort was 56.6 ± 10 years of age (mean ± SD), 63.8% male, with BMI 34.2 ± 6.7 kg/m

CONCLUSIONS: In the …

Association Of Baseline Characteristics With Insulin Sensitivity And Β-Cell Function In The Glycemia Reduction Approaches In Diabetes: A Comparative Effectiveness (Grade) Study Cohort, Neda Rasouli, Naji Younes, Kristina M Utzschneider, Silvio E Inzucchi, Ashok Balasubramanyam, Andrea L Cherrington, Faramarz Ismail-Beigi, Robert M Cohen, Darin E Olson, Ralph A Defronzo, William H Herman, John M Lachin, Steven E Kahn

Faculty, Staff and Students Publications

OBJECTIVE: We investigated sex and racial differences in insulin sensitivity, β-cell function, and glycated hemoglobin (HbA

RESEARCH DESIGN AND METHODS: This is a cross-sectional analysis of baseline data from 3,108 GRADE (Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study) participants. All had type 2 diabetes diagnosedβ-cell function were evaluated using the HOMA of insulin sensitivity and estimates from oral glucose tolerance tests, including the Matsuda Index, insulinogenic index, C-peptide index, and oral disposition index (DI).

RESULTS: The cohort was 56.6 ± 10 years of age (mean ± SD), 63.8% male, with BMI 34.2 ± 6.7 kg/m

CONCLUSIONS: In the …

Highlights From Studies Presented At The American Heart Association Scientific Session 2020: Navigating New Roads In Prevention, Aliza Hussain, Mahmoud Al Rifai, Dhruv Mahtta, Jing Liu, Vardhmaan Jain, Salim S Virani

Faculty, Staff and Students Publications

PURPOSE OF THE REVIEW: This review highlights late-breaking science presented at the American Heart Association Scientific Session 2020 that demonstrated advancements in preventative cardiology and introduced novel treatment approaches for the management of chronic kidney disease, type 2 diabetes, and/or heart failure.

RECENT FINDINGS: The studies reviewed include clinical trials that assessed the use of omecamtiv in the treatment of heart failure with reduced heart failure (GALACTIC-HF); effects of sotagliflozin in patients with diabetes and recent heart failure exacerbation; cardiovascular outcomes with the use of omega-3 carboxylic acids in patients with high vascular risk and atherogenic dyslipidemia (STRENGTH) and omega-3 …

Adipocyte-Specific Ablation Of Pu1 Promotes Energy Expenditure And Ameliorates Metabolic Syndrome In Aging Mice, Ke Yun Chen, Alejandra De Angulo, Xin Guo, Aditya More, Scott A Ochsner, Eduardo Lopez, David Saul, Weijun Pang, Yuxiang Sun, Neil J Mckenna, Qiang Tong

Faculty, Staff and Students Publications

Objective: Although PU.1/Spi1 is known as a master regulator for macrophage development and function, we have reported previously that it is also expressed in adipocytes and is transcriptionally induced in obesity. Here, we investigated the role of adipocyte PU.1 in the development of the age-associated metabolic syndrome.

Methods: We generated mice with adipocyte-specific PU.1 knockout, assessed metabolic changes in young and older adult PU.1^fl/fl (control) and AdipoqCre PU.1^fl/fl (aPU.1KO) mice, including body weight, body composition, energy expenditure, and glucose homeostasis. We also performed transcriptional analyses using RNA-Sequencing of adipocytes from these mice.

Results: aPU.1KO mice have elevated energy …

Mitochondrial Regulation Of Diabetic Kidney Disease, Daniel L Galvan, Koki Mise, Farhad R Danesh

Faculty, Staff and Students Publications

The role and nature of mitochondrial dysfunction in diabetic kidney disease (DKD) has been extensively studied. Yet, the molecular drivers of mitochondrial remodeling in DKD are poorly understood. Diabetic kidney cells exhibit a cascade of mitochondrial dysfunction ranging from changes in mitochondrial morphology to significant alterations in mitochondrial biogenesis, biosynthetic, bioenergetics and production of reactive oxygen species (ROS). How these changes individually or in aggregate contribute to progression of DKD remain to be fully elucidated. Nevertheless, because of the remarkable progress in our basic understanding of the role of mitochondrial biology and its dysfunction in DKD, there is great excitement …

Identification Of Deep-Intronic Splice Mutations In A Large Cohort Of Patients With Inherited Retinal Diseases, Xinye Qian, Jun Wang, Meng Wang, Austin D Igelman, Kaylie D Jones, Yumei Li, Keqing Wang, Kerry E Goetz, David G Birch, Paul Yang, Mark E Pennesi, Rui Chen

Faculty, Staff and Students Publications

High throughput sequencing technologies have revolutionized the identification of mutations responsible for a diverse set of Mendelian disorders, including inherited retinal disorders (IRDs). However, the causal mutations remain elusive for a significant proportion of patients. This may be partially due to pathogenic mutations located in non-coding regions, which are largely missed by capture sequencing targeting the coding regions. The advent of whole-genome sequencing (WGS) allows us to systematically detect non-coding variations. However, the interpretation of these variations remains a significant bottleneck. In this study, we investigated the contribution of deep-intronic splice variants to IRDs. WGS was performed for a cohort …

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 …

The E3 Ligase Traf4 Promotes Igf Signaling By Mediating Atypical Ubiquitination Of Irs-1, Wenjuan Yu, Ramesh Singh, Zhao Wang, Bert W O'Malley, Ping Yi

Faculty, Staff and Students Publications

Insulin-like growth factor (IGF) is a potent mitogen that activates the IGF receptor (IGFR)/insulin receptor substrate (IRS) axis, thus stimulating growth in normal cells and uncontrolled cell proliferation in cancer. Posttranslational modifications of IRS such as ubiquitination tightly control IGF signaling, and we previously identified IRS-1 as a potential substrate for the E3 ubiquitin ligase TRAF4 using an unbiased screen. Here we provide evidence that TRAF4-mediated ubiquitination of IRS-1 is physiologically relevant and crucial for IGF signal transduction. Through site-directed mutagenesis we found that TRAF4 promotes an atypical K29-linked ubiquitination at the C-terminal end of IRS-1. Its depletion abolishes AKT …

A Gigantic Uterine Leiomyoma And Big Bilateral Adrenal Myelolipomas As A Result Of Untreated Congenital Adrenal Hyperplasia, Betty La, Celestine Tung, Eugene A Choi, Ha Nguyen

Faculty, Staff and Students Publications

INTRODUCTION: Patients with congenital adrenal hyperplasia (CAH) can present early with salt wasting, adrenal insufficiency, and hyperandrogenism. Late consequences as a result of untreated CAH are now rarely seen. We present a patient with a massive uterine leiomyoma and bilateral adrenal myelolipomas due to longstanding treatment noncompliance.

CASE REPORT: A female patient with CAH was treated with glucocorticoids until the age of 29 years when they stopped with the intention of identifying as a male. The patient then presented with abdominal pain and distension. Computed tomography images of the abdomen and pelvis revealed a 31 × 35 × 31-cm abdominal …

Hemoglobin A1c Threshold For Reduction In Bone Turnover In Men With Type 2 Diabetes Mellitus, Sabaa Joad, Elliot Ballato, Fnu Deepika, Giulia Gregori, Alcibiades Leonardo Fleires-Gutierrez, Georgia Colleluori, Lina Aguirre, Rui Chen, Vittoria Russo, Virginia Carolina Fuenmayor Lopez, Clifford Qualls, Dennis T Villareal, Reina Armamento-Villareal

Faculty, Staff and Students Publications

BACKGROUND: Emerging data suggest that type 2 diabetes mellitus (T2D) is associated with an increased risk for fractures despite relatively normal or increased bone mineral density (BMD). Although the mechanism for bone fragility in T2D patients is multifactorial, whether glycemic control is important in generating this impairment in bone metabolism remains unclear. The purpose of our study is to identify a hemoglobin A1c (A1c) threshold level by which reduction in bone turnover begins in men with T2D.

METHOD: A cross-sectional analysis of baseline data was obtained from 217 men, ages 35-65, regardless of the presence or absence of hypogonadism or …

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 …

Mir-30a Targets Gene Networks That Promote Browning Of Human And Mouse Adipocytes, Pradip K Saha, Mark P Hamilton, Kimal Rajapakshe, Vasanta Putluri, Jessica B Felix, Peter Masschelin, Aaron R Cox, Mandeep Bajaj, Nagireddy Putluri, Cristian Coarfa, Sean M Hartig

Faculty, Staff and Students Publications

MicroRNA-30a (miR-30a) impacts adipocyte function, and its expression in white adipose tissue (WAT) correlates with insulin sensitivity in obesity. Bioinformatic analysis demonstrates that miR-30a expression contributes to 2% of all miRNA expression in human tissues. However, molecular mechanisms of miR-30a function in fat cells remain unclear. Here, we expanded our understanding of how miR-30a expression contributes to antidiabetic peroxisome proliferator-activated receptor-γ (PPARγ) agonist activity and metabolic functions in adipocytes. We found that WAT isolated from diabetic patients shows reduced miR-30a levels and diminished expression of the canonical PPARγ target genes ADIPOQ and FABP4 relative to lean counterparts. In human adipocytes, …

Glycemic Control And Infections Among Us Hemodialysis Patients With Diabetes Mellitus, Jinnie J Rhee, Yuanchao Zheng, Sai Liu, Maria E Montez-Rath, Richard J Hamill, Julie H Ishida, Wolfgang C Winkelmayer

Faculty, Staff and Students Publications

INTRODUCTION: Patients with diabetes mellitus (DM) on hemodialysis (HD) may be particularly vulnerable to infections.

METHODS: We used merged data from the United States Renal Data System and electronic health records data from a large US dialysis provider to retrospectively examine the association between glycemic control and infections in these patients. Adult patients with DM aged ≥18 years who initiated in-center maintenance HD treatment from 2006 to 2011 and survived >90 days were included. Quarterly mean time-averaged hemoglobin A1c (HbA1c) values were categorized into

RESULTS: In a cohort of 33,753 eligible patients, those with higher HbA1c levels had higher rates …