Endocrine System Diseases Commons^™

Anoctamin 4 Channel Currents Activate Glucose-Inhibited Neurons In The Mouse Ventromedial Hypothalamus During Hypoglycemia, Longlong Tu, Jonathan C Bean, Yang He, Hailan Liu, Meng Yu, Hesong Liu, Nan Zhang, Na Yin, Junying Han, Nikolas A Scarcelli, Kristine M Conde, Mengjie Wang, Yongxiang Li, Bing Feng, Peiyu Gao, Zhao-Lin Cai, Makoto Fukuda, Mingshan Xue, Qingchun Tong, Yongjie Yang, Lan Liao, Jianming Xu, Chunmei Wang, Yanlin He, Yong Xu

Faculty, Staff and Student Publications

Glucose is the basic fuel essential for maintenance of viability and functionality of all cells. However, some neurons - namely, glucose-inhibited (GI) neurons - paradoxically increase their firing activity in low-glucose conditions and decrease that activity in high-glucose conditions. The ionic mechanisms mediating electric responses of GI neurons to glucose fluctuations remain unclear. Here, we showed that currents mediated by the anoctamin 4 (Ano4) channel are only detected in GI neurons in the ventromedial hypothalamic nucleus (VMH) and are functionally required for their activation in response to low glucose. Genetic disruption of the Ano4 gene in VMH neurons reduced blood …

Vitamin B2 Enables Regulation Of Fasting Glucose Availability, Peter M Masschelin, Pradip Saha, Scott A Ochsner, Aaron R Cox, Kang Ho Kim, Jessica B Felix, Robert Sharp, Xin Li, Lin Tan, Jun Hyoung Park, Liping Wang, Vasanta Putluri, Philip L Lorenzi, Alli M Nuotio-Antar, Zheng Sun, Benny Abraham Kaipparettu, Nagireddy Putluri, David D Moore, Scott A Summers, Neil J Mckenna, Sean M Hartig

Faculty, Staff and Students Publications

Flavin adenine dinucleotide (FAD) interacts with flavoproteins to mediate oxidation-reduction reactions required for cellular energy demands. Not surprisingly, mutations that alter FAD binding to flavoproteins cause rare inborn errors of metabolism (IEMs) that disrupt liver function and render fasting intolerance, hepatic steatosis, and lipodystrophy. In our study, depleting FAD pools in mice with a vitamin B2-deficient diet (B2D) caused phenotypes associated with organic acidemias and other IEMs, including reduced body weight, hypoglycemia, and fatty liver disease. Integrated discovery approaches revealed B2D tempered fasting activation of target genes for the nuclear receptor PPARα, including those required for gluconeogenesis. We also found …

Secretogranin Iii Selectively Promotes Vascular Leakage In The Deep Vascular Plexus Of Diabetic Retinopathy, Liyang Ji, Prabuddha Waduge, Yan Wu, Chengchi Huang, Avinash Kaur, Paola Oliveira, Hong Tian, Jinsong Zhang, J Timothy Stout, Christina Y Weng, Keith A Webster, Wei Li

Faculty, Staff and Students Publications

Diabetic retinopathy (DR), a leading cause of vision loss in working-age adults, induces mosaic patterns of vasculopathy that may be associated with spatial heterogeneity of intraretinal endothelial cells. We recently reported that secretogranin III (Scg3), a neuron-derived angiogenic and vascular leakage factor, selectively binds retinal vessels of diabetic but not healthy mice. Here, we investigated endothelial heterogeneity of three retinal vascular plexuses in DR pathogenesis and the therapeutic implications. Our unique in vivo ligand binding assay detected a 22.7-fold increase in Scg3 binding to retinal vessels of diabetic mice relative to healthy mice. Functional immunohistochemistry revealed that Scg3 predominantly binds …

Targeting Energy Intake And Circadian Biology To Engage Mechanisms Of Aging In Older Adults With Obesity: Calorie Restriction And Time-Restricted Eating, Satchidananda Panda, Geraldine Maier, Dennis T Villareal

Faculty, Staff and Students Publications

With the rise in obesity across age groups, it has been a hindrance to engaging in physical activity and mobility in older adults. Daily calorie restriction (CR) up to 25% has been the cornerstone of obesity management even though the safety in older adults remains incompletely understood. Although some adults can follow CR with clinically significant weight loss and improved health metrics, CR faces 2 obstacles-many fail to adopt CR and even among those who can adopt it short term, long-term compliance can be difficult. Furthermore, there is a continuing debate about the net benefits of CR-induced weight loss in …

Whole Genome Analysis For 163 Grnas In Cas9-Edited Mice Reveals Minimal Off-Target Activity, Kevin A Peterson, Sam Khalouei, Nour Hanafi, Joshua A Wood, Denise G Lanza, Lauri G Lintott, Brandon J Willis, John R Seavitt, Robert E Braun, Mary E Dickinson, Jacqueline K White, K C Kent Lloyd, Jason D Heaney, Stephen A Murray, Arun Ramani, Lauryl M J Nutter

Faculty, Staff and Students Publications

Genome editing with CRISPR-associated (Cas) proteins holds exceptional promise for "correcting" variants causing genetic disease. To realize this promise, off-target genomic changes cannot occur during the editing process. Here, we use whole genome sequencing to compare the genomes of 50 Cas9-edited founder mice to 28 untreated control mice to assess the occurrence of S. pyogenes Cas9-induced off-target mutagenesis. Computational analysis of whole-genome sequencing data detects 26 unique sequence variants at 23 predicted off-target sites for 18/163 guides used. While computationally detected variants are identified in 30% (15/50) of Cas9 gene-edited founder animals, only 38% (10/26) of the variants in 8/15 …

Steroid Receptor Coactivator 3 Is A Key Modulator Of Regulatory T Cell-Mediated Tumor Evasion, Sang Jun Han, Prashi Jain, Yosef Gilad, Yan Xia, Nuri Sung, Mi Jin Park, Adam M Dean, Rainer B Lanz, Jianming Xu, Clifford C Dacso, David M Lonard, Bert W O'Malley

Faculty, Staff and Students Publications

Steroid receptor coactivator 3 (SRC-3) is most strongly expressed in regulatory T cells (Tregs) and B cells, suggesting that it plays an important role in the regulation of Treg function. Using an aggressive E0771 mouse breast cell line syngeneic immune-intact murine model, we observed that breast tumors were "permanently eradicated" in a genetically engineered tamoxifen-inducible Treg-cell-specific SRC-3 knockout (KO) female mouse that does not possess a systemic autoimmune pathological phenotype. A similar eradication of tumor was noted in a syngeneic model of prostate cancer. A subsequent injection of additional E0771 cancer cells into these mice showed continued resistance to tumor …

Circadian Clock Control Of Mrtf/Srf Pathway Suppresses Beige Adipocyte Thermogenic Recruitment, Xuekai Xiong, Weini Li, Ruya Liu, Pradip Saha, Vijay Yechoor, Ke Ma

Faculty, Staff and Students Publications

The morphological transformation of adipogenic progenitors into mature adipocytes requires dissolution of actin cytoskeleton with loss of myocardin-related transcription factor (MRTF)/serum response factor (SRF) activity. Circadian clock confers temporal control in adipogenic differentiation, while the actin cytoskeleton-MRTF/SRF signaling transduces extracellular physical niche cues. Here, we define a novel circadian transcriptional control involved in actin cytoskeleton-MRTF/SRF signaling cascade that modulates beige fat thermogenic function. Key components of actin dynamic-MRTF/SRF pathway display circadian regulation in beige fat depot. The core clock regulator, brain and muscle arnt-like 1 (Bmal1), exerts direct transcriptional control of genes within the actin dynamic-MRTF/SRF cascade that impacts actin …

Hepatocytes Demarcated By Ephb2 Contribute To The Progression Of Nonalcoholic Steatohepatitis, Yang Xiao, Kirill Batmanov, Wenxiang Hu, Kun Zhu, Alexander Y Tom, Dongyin Guan, Chunjie Jiang, Lan Cheng, Sam J Mccright, Eric C Yang, Matthew R Lanza, Yifan Liu, David A Hill, Mitchell A Lazar

Faculty, Staff and Students Publications

Current therapeutic strategies for treating nonalcoholic steatohepatitis (NASH) have failed to alleviate liver fibrosis, which is a devastating feature leading to hepatic dysfunction. Here, we integrated single-nucleus transcriptomics and epigenomics to characterize all major liver cell types during NASH development in mice and humans. The bifurcation of hepatocyte trajectory with NASH progression was conserved between mice and humans. At the nonalcoholic fatty liver (NAFL) stage, hepatocytes exhibited metabolic adaptation, whereas at the NASH stage, a subset of hepatocytes was enriched for the signatures of cell adhesion and migration, which were mainly demarcated by receptor tyrosine kinase ephrin type B receptor …

Genome-Wide Screening Reveals The Genetic Basis Of Mammalian Embryonic Eye Development, Justine M Chee, Louise Lanoue, Dave Clary, Kendall Higgins, Lynette Bower, Ann Flenniken, Ruolin Guo, David J Adams, Fatima Bosch, Robert E Braun, Steve D M Brown, H-J Genie Chin, Mary E Dickinson, Chih-Wei Hsu, Michael Dobbie, Xiang Gao, Sanjeev Galande, Anne Grobler, Jason D Heaney, Yann Herault, Martin Hrabe De Angelis, Fabio Mammano, Lauryl M J Nutter, Helen Parkinson, Chuan Qin, Toshi Shiroishi, Radislav Sedlacek, J-K Seong, Ying Xu, Brian Brooks, Colin Mckerlie, K C Kent Lloyd, Henrik Westerberg, Ala Moshiri

Faculty, Staff and Students Publications

BACKGROUND: Microphthalmia, anophthalmia, and coloboma (MAC) spectrum disease encompasses a group of eye malformations which play a role in childhood visual impairment. Although the predominant cause of eye malformations is known to be heritable in nature, with 80% of cases displaying loss-of-function mutations in the ocular developmental genes OTX2 or SOX2, the genetic abnormalities underlying the remaining cases of MAC are incompletely understood. This study intended to identify the novel genes and pathways required for early eye development. Additionally, pathways involved in eye formation during embryogenesis are also incompletely understood. This study aims to identify the novel genes and pathways …

Supplementing Glycine And N-Acetylcysteine (Glynac) In Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, And Aging Hallmarks: A Randomized Clinical Trial, Premranjan Kumar, Chun Liu, James Suliburk, Jean W Hsu, Raja Muthupillai, Farook Jahoor, Charles G Minard, George E Taffet, Rajagopal V Sekhar

Faculty, Staff and Students Publications

BACKGROUND: Elevated oxidative stress (OxS), mitochondrial dysfunction, and hallmarks of aging are identified as key contributors to aging, but improving/reversing these defects in older adults (OA) is challenging. In prior studies, we identified that deficiency of the intracellular antioxidant glutathione (GSH) could play a role and reported that supplementing GlyNAC (combination of glycine and N-acetylcysteine [NAC]) in aged mice improved GSH deficiency, OxS, mitochondrial fatty-acid oxidation (MFO), and insulin resistance (IR). To test whether GlyNAC supplementation in OA could improve GSH deficiency, OxS, mitochondrial dysfunction, IR, physical function, and aging hallmarks, we conducted a placebo-controlled randomized clinical trial.

METHODS: Twenty-four …

Supplementing Glycine And N-Acetylcysteine (Glynac) In Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, And Aging Hallmarks: A Randomized Clinical Trial, Premranjan Kumar, Chun Liu, James Suliburk, Jean W Hsu, Raja Muthupillai, Farook Jahoor, Charles G Minard, George E Taffet, Rajagopal V Sekhar

Faculty, Staff and Students Publications

BACKGROUND: Elevated oxidative stress (OxS), mitochondrial dysfunction, and hallmarks of aging are identified as key contributors to aging, but improving/reversing these defects in older adults (OA) is challenging. In prior studies, we identified that deficiency of the intracellular antioxidant glutathione (GSH) could play a role and reported that supplementing GlyNAC (combination of glycine and N-acetylcysteine [NAC]) in aged mice improved GSH deficiency, OxS, mitochondrial fatty-acid oxidation (MFO), and insulin resistance (IR). To test whether GlyNAC supplementation in OA could improve GSH deficiency, OxS, mitochondrial dysfunction, IR, physical function, and aging hallmarks, we conducted a placebo-controlled randomized clinical trial.

METHODS: Twenty-four …

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 …

Nanocurcumin Combined With Insulin Alleviates Diabetic Kidney Disease Through P38/P53 Signaling Axis, Raghu Ganugula, Nikhil K Nuthalapati, Subhash Dwivedi, Dianxiong Zou, Meenakshi Arora, Richard Friend, David Sheikh-Hamad, Rita Basu, M N V Ravi Kumar

Faculty, Staff and Students Publications

Treatments for diabetic kidney disease (DKD) mainly focus on managing hyperglycemia and hypertension, but emerging evidence suggests that inflammation also plays a role in the pathogenesis of DKD. This 10-week study evaluated the efficacy of daily oral nanoparticulate-curcumin (nCUR) together with long-acting insulin (INS) to treat DKD in a rodent model. Diabetic rats were dosed with unformulated CUR alone, nCUR alone or together with INS, or INS alone. The progression of diabetes was reflected by increases in plasma fructosamine, blood urea nitrogen, creatinine, bilirubin, ALP, and decrease in albumin and globulins. These aberrancies were remedied by nCUR+INS or INS but …

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 …

Effect Of A Glp-1 Mimetic On The Insulin Response To Oral Sugar Testing In Horses, Darko Stefanovski, Mary A Robinson, Andrew Van Eps

Faculty, Staff and Student Publications

BACKGROUND: Insulin dysregulation (ID) is the most important risk factor for the development of laminitis in horses and therapies to control it are needed.

HYPOTHESIS/OBJECTIVES: To assess the effects of a single dose of the synthetic GLP-1 analog exenatide on postprandial insulin dynamics. We hypothesized that exenatide would improve insulin sensitivity and lower postprandial blood insulin concentrations.

STUDY DESIGN: Randomized, crossover, experimental study.

ANIMALS: Six horses (3 mares, 3 geldings; 2 with normal insulin regulation [NIR] and 4 with mild ID).

METHODS: Horses completed both study arms: subcutaneous administration of exenatide (or no treatment) 30 min before an oral sugar …

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 …