1
|
Lee MJ, Puri V, Fried SK. Metabolic and structural remodeling during browning of primary human adipocytes derived from omental and subcutaneous depots. Obesity (Silver Spring) 2024; 32:70-79. [PMID: 37929774 DOI: 10.1002/oby.23912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 11/07/2023]
Abstract
OBJECTIVE This study investigated remodeling of cellular metabolism and structures during browning of primary human adipocytes derived from both visceral and subcutaneous adipose tissues. Effects of glucocorticoids on the browning were also assessed. METHODS Differentiated omental and subcutaneous human adipocytes were treated with rosiglitazone, with or without dexamethasone, and expression levels of brite adipocyte markers, lipolysis, and lipid droplet and mitochondrial structures were examined. RESULTS Both omental and subcutaneous adipocytes acquired brite phenotypes upon peroxisome proliferator-activated receptor-γ agonist treatment, and dexamethasone tended to enhance the remodeling. Although rosiglitazone increased lipolysis during treatment, brite adipocytes exhibited lower basal lipolytic rates and enhanced responses to β-adrenergic agonists or atrial natriuretic peptide. Transcriptome analysis identified induction of both breakdown and biosynthesis of lipids in brite adipocytes. After 60+ days in culture, lipid droplet size increased to ~50 microns, becoming almost unilocular in control adipocytes, and after browning, they acquired paucilocular morphology, clusters of small lipid droplets (1-2 micron) surrounded by mitochondria appearing on the periphery of the central large one. CONCLUSIONS Metabolic and structural remodeling during browning of primary human adipocytes is similar to previous findings in human adipocytes in vivo, supporting their uses for mechanical studies investigating browning with translational relevance.
Collapse
Affiliation(s)
- Mi-Jeong Lee
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, Hawaii, USA
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Vishwajeet Puri
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Biomedical Sciences and Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
| | - Susan K Fried
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine, New York, New York, USA
| |
Collapse
|
2
|
Qiu J, Fan Q, Xu S, Wang D, Chen J, Wang S, Hu T, Ma X, Cheng Y, Xu L. A fluorinated peptide with high serum- and lipid-tolerence for the delivery of siRNA drugs to treat obesity and metabolic dysfunction. Biomaterials 2022; 285:121541. [DOI: 10.1016/j.biomaterials.2022.121541] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/14/2022] [Accepted: 04/22/2022] [Indexed: 12/12/2022]
|
3
|
Metformin booster adipocyte-targeted gene therapy for the treatment of obesity and related metabolic syndromes. Sci China Chem 2022. [DOI: 10.1007/s11426-021-1185-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
4
|
de Frutos S, Griera M, Hatem-Vaquero M, Campillo S, Gutiérrez-Calabres E, García-Ayuso D, Pardo M, Calleros L, Rodríguez-Puyol M, Rodríguez-Puyol D. The integrin beta1 modulator Tirofiban prevents adipogenesis and obesity by the overexpression of integrin-linked kinase: a pre-clinical approach in vitro and in vivo. Cell Biosci 2022; 12:10. [PMID: 35090553 PMCID: PMC8796419 DOI: 10.1186/s13578-022-00746-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/14/2022] [Indexed: 02/04/2023] Open
Abstract
Background Obesity is caused by the enlargement of the white adipose tissue (WAT) depots, characterized by the hypertrophic enlargement of malfunctioning adipocytes within WAT which increases the storage of triglycerides (TG) in the lipid droplets (LD). Adipogenesis pathways as well as the expression and activity of some extracellular matrix receptors integrins are upregulated. Integrinβ1 (INTB1) is the main isoform involved in WAT remodeling during obesity and insulin resistance-related diseases. We recently described Integrin Linked Kinase (ILK), a scaffold protein recruited by INTB1, as an important mediator of WAT remodeling and insulin resistance. As the few approved drugs to fight obesity have brought long-term cardiovascular side effects and given that the consideration of INTB1 and/or ILK modulation as anti-obesogenic strategies remains unexplored, we aimed to evaluate the anti-obesogenic capacity of the clinically approved anticoagulant Tirofiban (TF), stated in preclinical studies as a cardiovascular protector. Methods Fully differentiated adipocytes originating from C3H10T1/2 were exposed to TF and were co-treated with specific INTB1 blockers or with siRNA-based knockdown ILK expression. Lipid-specific dyes were used to determine the TG content in LD. The genetic expression pattern of ILK, pro-inflammatory cytokines (MCP1, IL6), adipogenesis (PPARγ, Leptin), thermogenesis (UCP1), proliferation (PCNA), lipid metabolism (FASN, HSL, ATGL), and metabolite transporters (FABP4, FAT, AQP7) were detected using quantitative PCR. Cytoskeletal actin polymerization was detected by confocal microscopy. Immunoblotting was performed to detect INTB1 phosphorylation at Thr788/9 and ILK activity as phosphorylation levels of protein kinase B (AKT) in Ser473 and glycogen synthase kinase 3β (GSK3β) at Ser9. TF was intraperitoneally administered once per day to wildtype and ILK knockdown mice (cKDILK) challenged with a high-fat diet (HFD) or control diet (STD) for 2 weeks. Body and WAT weight gains were compared. The expression of ILK and other markers was determined in the visceral epididymal (epi) and inguinal subcutaneous (sc) WAT. Results TF reduced TG content and the expression of adipogenesis markers and transporters in adipocytes, while UCP-1 expression was increased and the expression of lipases, cytokines or PCNA was not affected. Mechanistically, TF rapidly increased and faded the intracellular phosphorylation of INTB1 but not AKT or GSK3β. F-actin levels were rapidly decreased, and INTB1 blockade avoided the TF effect. After 24 h, ILK expression and phosphorylation rates of AKT and GSK3β were upregulated, while ILK silencing increased TG content. INTB1 blockade and ILK silencing avoided TF effects on the TG content and the transcriptional expression of PPARγ and UCP1. In HFD-challenged mice, the systemic administration of TF for several days reduced the weight gain on WAT depots. TF reduced adipogenesis and pro-inflammatory biomarkers and increased lipolysis markers HSL and FAT in epiWAT from HFD, while increased UCP1 in scWAT. In both WATs, TF upregulated ILK expression and activity, while no changes were observed in other tissues. In HFD-fed cKDILK, the blunted ILK in epiWAT worsened weight gain and avoided the anti-obesogenic effect of in vivo TF administration. Conclusions ILK downregulation in WAT can be considered a biomarker of obesity establishment. Via an INTB1-ILK axis, TF restores malfunctioning hypertrophied WAT by changing the expression of adipocyte-related genes, increasing ILK expression and activity, and reducing TG storage. TF prevents obesity, a property to be added to its anticoagulant and cardiovascular protective advantages. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00746-1.
Collapse
|
5
|
Rendon CJ, Flood E, Thompson JM, Chirivi M, Watts SW, Contreras GA. PIEZO1 mechanoreceptor activation reduces adipogenesis in perivascular adipose tissue preadipocytes. Front Endocrinol (Lausanne) 2022; 13:995499. [PMID: 36120469 PMCID: PMC9471253 DOI: 10.3389/fendo.2022.995499] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
During hypertension, vascular remodeling allows the blood vessel to withstand mechanical forces induced by high blood pressure (BP). This process is well characterized in the media and intima layers of the vessel but not in the perivascular adipose tissue (PVAT). In PVAT, there is evidence for fibrosis development during hypertension; however, PVAT remodeling is poorly understood. In non-PVAT depots, mechanical forces can affect adipogenesis and lipogenic stages in preadipocytes. In tissues exposed to high magnitudes of pressure like bone, the activation of the mechanosensor PIEZO1 induces differentiation of progenitor cells towards osteogenic lineages. PVAT's anatomical location continuously exposes it to forces generated by blood flow that could affect adipogenesis in normotensive and hypertensive states. In this study, we hypothesize that activation of PIEZO1 reduces adipogenesis in PVAT preadipocytes. The hypothesis was tested using pharmacological and mechanical activation of PIEZO1. Thoracic aorta PVAT (APVAT) was collected from 10-wk old male SD rats (n=15) to harvest preadipocytes that were differentiated to adipocytes in the presence of the PIEZO1 agonist Yoda1 (10 µM). Mechanical stretch was applied with the FlexCell System at 12% elongation, half-sine at 1 Hz simultaneously during the 4 d of adipogenesis (MS+, mechanical force applied; MS-, no mechanical force used). Yoda1 reduced adipogenesis by 33% compared with CON and, as expected, increased cytoplasmic Ca2+ flux. MS+ reduced adipogenesis efficiency compared with MS-. When Piezo1 expression was blocked with siRNA [siPiezo1; NC=non-coding siRNA], the anti-adipogenic effect of Yoda1 was reversed in siPiezo1 cells but not in NC; in contrast, siPiezo1 did not alter the inhibitory effect of MS+ on adipogenesis. These data demonstrate that PIEZO1 activation in PVAT reduces adipogenesis and lipogenesis and provides initial evidence for an adaptive response to excessive mechanical forces in PVAT during hypertension.
Collapse
Affiliation(s)
- C. Javier Rendon
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI, United States
- *Correspondence: C. Javier Rendon,
| | - Emma Flood
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Janice M. Thompson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Miguel Chirivi
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI, United States
| | - Stephanie W. Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - G. Andres Contreras
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
6
|
Nimitphong H, Guo W, Holick MF, Fried SK, Lee MJ. Vitamin D Inhibits Adipokine Production and Inflammatory Signaling Through the Vitamin D Receptor in Human Adipocytes. Obesity (Silver Spring) 2021; 29:562-568. [PMID: 33624437 DOI: 10.1002/oby.23109] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/01/2020] [Accepted: 12/05/2020] [Indexed: 11/10/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the effects of vitamin D on adipokine expression and inflammation in human adipose tissues and adipocytes and evaluate the molecular mechanisms involved. METHODS Omental and abdominal subcutaneous human adipose tissues were treated with 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), and adipokine levels were measured. Vitamin D effects were measured with or without dexamethasone because glucocorticoids are known to affect vitamin D actions. Using RNA interference, we examined whether the vitamin D receptor (VDR) mediated vitamin D actions on adipokine expression and inflammatory signaling pathways in human adipocytes. RESULTS mRNA levels and secretion of leptin and IL-6 were suppressed by 1,25(OH)2 D3 in omental adipose tissues. Cotreatment with dexamethasone did not affect these inhibitory actions but partially blocked CYP24A1 induction. Similar results were observed in the subcutaneous depot. In addition, 1,25(OH)2 D3 suppressed leptin and IL-6 expression as well as nuclear factor-κB and extracellular signal-regulated kinase-1/2 phosphorylation in human adipocytes. Adipokine expression also was decreased by 25-hydroxyvitamin D3 (25(OH)D3 ), but not vitamin D3 . Knockdown of VDR increased the inflammatory signaling activity in the control condition and blocked the inhibitory effects of 1,25(OH)2 D3 on adipokine and inflammatory signaling pathways. CONCLUSION Vitamin D acts through VDR to inhibit inflammatory pathways and adipokine expression in human adipocytes. Increasing vitamin D status may ameliorate obesity-associated metabolic complications by decreasing adipose tissue inflammation.
Collapse
Affiliation(s)
- Hataikarn Nimitphong
- Department of Medicine, Section of Endocrinology and Metabolism, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Weimin Guo
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Michael F Holick
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Susan K Fried
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, Massachusetts, USA
- Diabetes Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Mi-Jeong Lee
- Department of Medicine, Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| |
Collapse
|
7
|
Morales LD, Cromack DT, Tripathy D, Fourcaudot M, Kumar S, Curran JE, Carless M, Göring HHH, Hu SL, Lopez-Alvarenga JC, Garske KM, Pajukanta P, Small KS, Glastonbury CA, Das SK, Langefeld C, Hanson RL, Hsueh WC, Norton L, Arya R, Mummidi S, Blangero J, DeFronzo RA, Duggirala R, Jenkinson CP. Further evidence supporting a potential role for ADH1B in obesity. Sci Rep 2021; 11:1932. [PMID: 33479282 PMCID: PMC7820614 DOI: 10.1038/s41598-020-80563-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/06/2020] [Indexed: 01/22/2023] Open
Abstract
Insulin is an essential hormone that regulates glucose homeostasis and metabolism. Insulin resistance (IR) arises when tissues fail to respond to insulin, and it leads to serious health problems including Type 2 Diabetes (T2D). Obesity is a major contributor to the development of IR and T2D. We previously showed that gene expression of alcohol dehydrogenase 1B (ADH1B) was inversely correlated with obesity and IR in subcutaneous adipose tissue of Mexican Americans. In the current study, a meta-analysis of the relationship between ADH1B expression and BMI in Mexican Americans, African Americans, Europeans, and Pima Indians verified that BMI was increased with decreased ADH1B expression. Using established human subcutaneous pre-adipocyte cell lines derived from lean (BMI < 30 kg m-2) or obese (BMI ≥ 30 kg m-2) donors, we found that ADH1B protein expression increased substantially during differentiation, and overexpression of ADH1B inhibited fatty acid binding protein expression. Mature adipocytes from lean donors expressed ADH1B at higher levels than obese donors. Insulin further induced ADH1B protein expression as well as enzyme activity. Knockdown of ADH1B expression decreased insulin-stimulated glucose uptake. Our findings suggest that ADH1B is involved in the proper development and metabolic activity of adipose tissues and this function is suppressed by obesity.
Collapse
Affiliation(s)
- Liza D Morales
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA.
| | | | - Devjit Tripathy
- South Texas Veterans Health Care System, San Antonio, TX, USA
- Department of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Marcel Fourcaudot
- Department of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Satish Kumar
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Joanne E Curran
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Melanie Carless
- Department of Population Health, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Harald H H Göring
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Shirley L Hu
- University of Texas Health Houston, School of Public Health, Brownsville, TX, USA
| | - Juan Carlos Lopez-Alvarenga
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Kristina M Garske
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Päivi Pajukanta
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | | | | | - Swapan K Das
- Internal Medicine-Endocrinology and Metabolism, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Carl Langefeld
- Department of Biostatistics and Data Science, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Robert L Hanson
- Phoenix Epidemiology and Clinical Research Branch, NIDDK, Phoenix, AZ, USA
| | - Wen-Chi Hsueh
- Phoenix Epidemiology and Clinical Research Branch, NIDDK, Phoenix, AZ, USA
| | - Luke Norton
- Department of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Rector Arya
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Srinivas Mummidi
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - John Blangero
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Ralph A DeFronzo
- South Texas Veterans Health Care System, San Antonio, TX, USA
- Department of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Ravindranath Duggirala
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA
| | - Christopher P Jenkinson
- South Texas Diabetes and Obesity Institute Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Edinburg/Harlingen/Brownsville, TX, USA.
| |
Collapse
|
8
|
Jash S, Banerjee S, Lee MJ, Farmer SR, Puri V. CIDEA Transcriptionally Regulates UCP1 for Britening and Thermogenesis in Human Fat Cells. iScience 2019; 20:73-89. [PMID: 31563853 PMCID: PMC6817690 DOI: 10.1016/j.isci.2019.09.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/02/2019] [Accepted: 09/10/2019] [Indexed: 12/16/2022] Open
Abstract
Our study identifies a transcriptional role of cell death-inducing DNA fragmentation factor-like effector A (CIDEA), a lipid-droplet-associated protein, whereby it regulates human adipocyte britening/beiging with consequences for the regulation of energy expenditure. The comprehensive transcriptome analysis revealed CIDEA's control over thermogenic function in brite/beige human adipocytes. In the absence of CIDEA, achieved by the modified dual-RNA-based CRISPR-Cas9nD10A system, adipocytes lost their britening capability, which was recovered upon CIDEA re-expression. Uncoupling protein 1 (UCP1), the most upregulated gene in brite human adipocytes, was suppressed in CIDEA knockout (KO) primary human adipocytes. Mechanistically, during induced britening, CIDEA shuttled from lipid droplets to the nucleus via an unusual nuclear bipartite signal in a concentration-dependent manner. In the nucleus, it specifically inhibited LXRα repression of UCP1 enhancer activity and strengthened PPARγ binding to UCP1 enhancer, hence driving UCP1 transcription. Overall, our study defines the role of CIDEA in increasing thermogenesis in human adipocytes.
Collapse
Affiliation(s)
- Sukanta Jash
- Department of Biomedical Sciences and Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA
| | - Sayani Banerjee
- Department of Biomedical Sciences and Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA
| | - Mi-Jeong Lee
- Icahn School of Medicine, Mount Sinai, New York, NY, USA
| | - Stephen R Farmer
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Vishwajeet Puri
- Department of Biomedical Sciences and Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA.
| |
Collapse
|
9
|
Lee MJ, Pickering RT, Shibad V, Wu Y, Karastergiou K, Jager M, Layne MD, Fried SK. Impaired Glucocorticoid Suppression of TGFβ Signaling in Human Omental Adipose Tissues Limits Adipogenesis and May Promote Fibrosis. Diabetes 2019; 68:587-597. [PMID: 30530781 PMCID: PMC6385749 DOI: 10.2337/db18-0955] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Visceral obesity is associated with insulin resistance and higher risk of type 2 diabetes and metabolic diseases. A limited ability of adipose tissues to remodel through the recruitment and differentiation of adipose stem cells (ASCs) is associated with adipose tissue inflammation and fibrosis and the metabolic syndrome. We show that the lower adipogenesis of omental (Om) compared with abdominal subcutaneous (Abdsc) ASCs was associated with greater secretion of TGFβ ligands that acted in an autocrine/paracrine loop to activate SMAD2 and suppress adipogenesis. Inhibition of TGFβ signaling rescued Om ASC differentiation. In Abdsc ASCs, low concentrations of dexamethasone suppressed TGFβ signaling and enhanced adipogenesis, at least in part by increasing TGFBR3 protein that can sequester TGFβ ligands. Om ASCs were resistant to these dexamethasone effects; recombinant TGFBR3 increased their differentiation. Pericellular fibrosis, a hallmark of dysfunctional adipose tissue, was greater in Om and correlated with higher level of tissue TGFβ signaling activity and lower ASC differentiation. We conclude that glucocorticoids restrain cell-autonomous TGFβ signaling in ASCs to facilitate adipogenesis and healthy remodeling in Abdsc and these processes are impaired in Om. Therapies directed at overcoming glucocorticoid resistance in visceral adipose tissue may improve remodeling and help prevent metabolic complications of visceral obesity.
Collapse
Affiliation(s)
- Mi-Jeong Lee
- Diabetes Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Obesity Research Center, Boston University School of Medicine, Boston, MA
| | - R Taylor Pickering
- Diabetes Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Obesity Research Center, Boston University School of Medicine, Boston, MA
| | - Varuna Shibad
- Obesity Research Center, Boston University School of Medicine, Boston, MA
| | - Yuanyuan Wu
- Obesity Research Center, Boston University School of Medicine, Boston, MA
| | - Kalypso Karastergiou
- Diabetes Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Obesity Research Center, Boston University School of Medicine, Boston, MA
| | - Mike Jager
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Matthew D Layne
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Susan K Fried
- Diabetes Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Obesity Research Center, Boston University School of Medicine, Boston, MA
| |
Collapse
|
10
|
Sharma VM, Vestergaard ET, Jessen N, Kolind-Thomsen P, Nellemann B, Nielsen TS, Vendelbo MH, Møller N, Sharma R, Lee KY, Kopchick JJ, Jørgensen JOL, Puri V. Growth hormone acts along the PPARγ-FSP27 axis to stimulate lipolysis in human adipocytes. Am J Physiol Endocrinol Metab 2019; 316:E34-E42. [PMID: 30325658 PMCID: PMC6417689 DOI: 10.1152/ajpendo.00129.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 10/01/2018] [Accepted: 10/03/2018] [Indexed: 12/22/2022]
Abstract
The lipolytic effects of growth hormone (GH) have been known for half a century and play an important physiological role for substrate metabolism during fasting. In addition, sustained GH-induced lipolysis is causally linked to insulin resistance. However, the underlying molecular mechanisms remain elusive. In the present study, we obtained experimental data in human subjects and used human adipose-derived stromal vascular cells (hADSCs) as a model system to elucidate GH-triggered molecular signaling that stimulates adipose tissue lipolysis and insulin resistance in human adipocytes. We discovered that GH downregulates the expression of fat-specific protein (FSP27), a negative regulator of lipolysis, by impairing the transcriptional ability of the master transcriptional regulator, peroxisome proliferator-activated receptor-γ (PPARγ) via MEK/ERK activation. Ultimately, GH treatment promotes phosphorylation of PPARγ at Ser273 and causes its translocation from nucleus to the cytosol. Surprisingly, FSP27 overexpression inhibited PPARγ Ser273 phosphorylation and promoted its nuclear retention. GH antagonist treatment had similar effects. Our study identifies a novel signaling mechanism by which GH transcriptionally induces lipolysis via the MEK/ERK pathway that acts along PPARγ-FSP27 in human adipose tissue.
Collapse
Affiliation(s)
- Vishva M Sharma
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| | - Esben Thyssen Vestergaard
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Pediatrics, Randers Regional Hospital, Randers, Denmark
| | - Niels Jessen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Research Laboratory for Biochemical Pathology, Aarhus University Hospital , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Peter Kolind-Thomsen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Research Laboratory for Biochemical Pathology, Aarhus University Hospital , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | | | - Thomas S Nielsen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Faculty of Health and Medical Sciences, The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen , Copenhagen , Denmark
| | - Mikkel Holm Vendelbo
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital , Aarhus , Denmark
| | - Niels Møller
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Rita Sharma
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| | - Kevin Y Lee
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| | - John J Kopchick
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
- Edison Biotechnology Institute, Ohio University , Athens, Ohio
| | - Jens Otto Lunde Jørgensen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Vishwajeet Puri
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| |
Collapse
|
11
|
Dendritic peptide bolaamphiphiles for siRNA delivery to primary adipocytes. Biomaterials 2018; 178:458-466. [PMID: 29705001 DOI: 10.1016/j.biomaterials.2018.04.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 04/11/2018] [Accepted: 04/13/2018] [Indexed: 12/31/2022]
Abstract
Obesity is a major risk factor for diabetes, heart disease and other health problems. Adipose tissue plays a central role in the development of obesity and obesity-associated diseases. Gene therapy targeting adipose tissue may provide a promising strategy for obesity treatment. However, nucleic acid delivery to adipose tissue or even cultured adipocytes is challenging due to low delivery efficacy and high toxicity of the current cationic lipid based delivery systems, or monoamphiphiles. Herein, we report using dendritic peptide bolaamphiphiles (bolas) to deliver siRNA to primary adipocytes and hepatocytes. The bola consists of two l-Lysine dendrons connected to a fluorocarbon core through disulfide linkages. The Lysine dendrons are functionalized with l-histidine and l-tryptophan to promote endosomal escape and cellular uptake. The bola exhibited over 70% knockdown of GAPDH gene in both primary adipocytes and hepatocytes. Importantly, different from Lipofectamine that significantly reduced genes involved in lipolysis, lipogenesis, fatty acid oxidation and ketogenesis, the bolas had little to no effect on these genes. These results demonstrate the bola as a promising new vector for clinical and experimental applications for delivery of siRNA to metabolic organs.
Collapse
|
12
|
Plaza A, Merino B, Cano V, Domínguez G, Pérez-Castells J, Fernández-Alfonso MS, Sengenès C, Chowen JA, Ruiz-Gayo M. Cholecystokinin is involved in triglyceride fatty acid uptake by rat adipose tissue. J Endocrinol 2018; 236:137-150. [PMID: 29339381 DOI: 10.1530/joe-17-0580] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 01/16/2018] [Indexed: 11/08/2022]
Abstract
The incorporation of plasma triglyceride (TG) fatty acids to white adipose tissue (WAT) depends on lipoprotein lipase (LPL), which is regulated by angiopoietin-like protein-4 (ANGPTL-4), an unfolding molecular chaperone that converts active LPL dimers into inactive monomers. The production of ANGPTL-4 is promoted by fasting and repressed by feeding. We hypothesized that the postprandial hormone cholecystokinin (CCK) facilitates the storage of dietary TG fatty acids in WAT by regulating the activity of the LPL/ANGPTL-4 axis and that it does so by acting directly on CCK receptors in adipocytes. We report that administration of CCK-8 (a bioactive fragment of CCK) to rats: (i) reduces plasma ANGTPL-4 levels; (ii) represses Angptl-4 expression in WAT and (iii) simultaneously enhances LPL activity in this tissue without inducing Lpl expression. In vivo CCK-8 effects are specifically antagonized by the CCK-2 receptor (CCK-2R) antagonist, L-365,260. Moreover, CCK-8 downregulates Angptl-4 expression in wild-type pre-adipocytes, an effect that is not observed in engineered pre-adipocytes lacking CCK-2R. These effects have functional consequences as CCK-8 was found to promote the uptake of dietary fatty acids by WAT, as demonstrated by means of proton nuclear magnetic resonance (1H-NMR). The efficacy of acute CCK-8 administration was not reduced after chronic CCK-8 treatment. Moreover, the effects of CCK-8 on WAT were not associated to the increase of circulating insulin. Our results show that cholecystokinin promotes lipid storage in WAT by acting on adipocyte CCK-2R, suggesting a pivotal role for CCK in TG homeostasis.
Collapse
Affiliation(s)
- Adrián Plaza
- Departamento de Ciencias Farmacéuticas y de la SaludFacultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| | - Beatriz Merino
- Departamento de Ciencias Farmacéuticas y de la SaludFacultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| | - Victoria Cano
- Departamento de Ciencias Farmacéuticas y de la SaludFacultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| | - Gema Domínguez
- Departamento de Química y BioquímicaFacultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| | - Javier Pérez-Castells
- Departamento de Química y BioquímicaFacultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| | | | - Coralie Sengenès
- STROMALabUniversité de Toulouse, CNRS ERL5311, EFS, INP-ENVT, Inserm U1031, UPS, Toulouse, France
| | - Julie A Chowen
- Departamento de EndocrinologíaHospital Infantil Universitario Niño Jesús, Instituto de Investigación Sanitaria Princesa, CIBEROBN Instituto Carlos III, Madrid, Spain
| | - Mariano Ruiz-Gayo
- Departamento de Ciencias Farmacéuticas y de la SaludFacultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| |
Collapse
|
13
|
Cell Models and Their Application for Studying Adipogenic Differentiation in Relation to Obesity: A Review. Int J Mol Sci 2016; 17:ijms17071040. [PMID: 27376273 PMCID: PMC4964416 DOI: 10.3390/ijms17071040] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/23/2016] [Accepted: 06/24/2016] [Indexed: 02/08/2023] Open
Abstract
Over the last several years, the increasing prevalence of obesity has favored an intense study of adipose tissue biology and the precise mechanisms involved in adipocyte differentiation and adipogenesis. Adipocyte commitment and differentiation are complex processes, which can be investigated thanks to the development of diverse in vitro cell models and molecular biology techniques that allow for a better understanding of adipogenesis and adipocyte dysfunction associated with obesity. The aim of the present work was to update the different animal and human cell culture models available for studying the in vitro adipogenic differentiation process related to obesity and its co-morbidities. The main characteristics, new protocols, and applications of the cell models used to study the adipogenesis in the last five years have been extensively revised. Moreover, we depict co-cultures and three-dimensional cultures, given their utility to understand the connections between adipocytes and their surrounding cells in adipose tissue.
Collapse
|
14
|
Lee MJ, Yang RZ, Karastergiou K, Smith SR, Chang JR, Gong DW, Fried SK. Low expression of the GILZ may contribute to adipose inflammation and altered adipokine production in human obesity. J Lipid Res 2016; 57:1256-63. [PMID: 27178044 DOI: 10.1194/jlr.m067728] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Indexed: 12/30/2022] Open
Abstract
The glucocorticoid-induced leucine zipper (GILZ), a primary target of glucocorticoids, is expressed in human adipocytes, but its importance in adipocyte function is unknown. Because TNFα is increased in obese adipose tissue and antagonizes a number of glucocorticoid actions, we investigated the interplay of these pathways. GILZ knockdown increased and GILZ overexpression decreased interleukin-6 (IL-6) and leptin mRNA and protein secretion. GILZ knockdown increased the magnitude of the glucocorticoid effect on leptin secretion, but did not affect the glucocorticoid suppression of IL-6. Although GILZ silencing decreased adiponectin mRNA levels, it did not affect the amount of adiponectin secreted. GILZ negatively modulated pro-inflammatory signaling pathways, blocking basal and TNFα-stimulated (1 h) p65 nuclear factor κB nuclear translocation and transcriptional activity by binding to p65 in the cytoplasm. GILZ silencing increased basal ERK1/2 and JNK phosphorylation, and decreased MAPK phosphatase-1 protein levels. Longer term TNFα (4 h or 24 h) treatment decreased GILZ expression in human adipocytes. Furthermore, adipose tissue GILZ mRNA levels were reduced in proportion to the degree of obesity and expression of inflammatory markers. Overall, these results suggest that GILZ antagonizes the pro-inflammatory effects of TNFα in human adipocytes, and its downregulation in obesity may contribute to adipose inflammation and dysregulated adipokine production, and thereby systemic metabolism.
Collapse
Affiliation(s)
- Mi-Jeong Lee
- Obesity Research Center, Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118 School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Rong-Ze Yang
- Department of Endocrinology, Diabetes, and Nutrition, School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Kalypso Karastergiou
- Obesity Research Center, Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118 School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Steven R Smith
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32804
| | - Jeffery R Chang
- Division of Reproductive Endocrinology, School of Medicine, University of California, San Diego, San Diego, CA 92093
| | - Da-Wei Gong
- Department of Endocrinology, Diabetes, and Nutrition, School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Susan K Fried
- Obesity Research Center, Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118 School of Medicine, University of Maryland, Baltimore, MD 21201
| |
Collapse
|
15
|
Isidor MS, Winther S, Basse AL, Petersen MCH, Cannon B, Nedergaard J, Hansen JB. An siRNA-based method for efficient silencing of gene expression in mature brown adipocytes. Adipocyte 2016; 5:175-85. [PMID: 27386153 PMCID: PMC4916873 DOI: 10.1080/21623945.2015.1111972] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/06/2015] [Accepted: 10/16/2015] [Indexed: 11/20/2022] Open
Abstract
Brown adipose tissue is a promising therapeutic target for opposing obesity, glucose intolerance and insulin resistance. The ability to modulate gene expression in mature brown adipocytes is important to understand brown adipocyte function and delineate novel regulatory mechanisms of non-shivering thermogenesis. The aim of this study was to optimize a lipofection-based small interfering RNA (siRNA) transfection protocol for efficient silencing of gene expression in mature brown adipocytes. We determined that a critical parameter was to deliver the siRNA to mature adipocytes by reverse transfection, i.e. transfection of non-adherent cells. Using this protocol, we effectively knocked down both high- and low-abundance transcripts in a model of mature brown adipocytes (WT-1) as well as in primary mature mouse brown adipocytes. A functional consequence of the knockdown was confirmed by an attenuated increase in uncoupled respiration (thermogenesis) in response to β-adrenergic stimulation of mature WT-1 brown adipocytes transfected with uncoupling protein 1 siRNA. Efficient gene silencing was also obtained in various mouse and human white adipocyte models (3T3-L1, primary mouse white adipocytes, hMADS) with the ability to undergo “browning.” In summary, we report an easy and versatile reverse siRNA transfection protocol to achieve specific silencing of gene expression in various models of mature brown and browning-competent white adipocytes, including primary cells.
Collapse
Affiliation(s)
- Marie S. Isidor
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Sally Winther
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Astrid L. Basse
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
| | - Jacob B. Hansen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
16
|
Estève D, Boulet N, Volat F, Zakaroff-Girard A, Ledoux S, Coupaye M, Decaunes P, Belles C, Gaits-Iacovoni F, Iacovoni JS, Rémaury A, Castel B, Ferrara P, Heymes C, Lafontan M, Bouloumié A, Galitzky J. Human white and brite adipogenesis is supported by MSCA1 and is impaired by immune cells. Stem Cells 2016; 33:1277-91. [PMID: 25523907 DOI: 10.1002/stem.1916] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 11/04/2014] [Accepted: 11/08/2014] [Indexed: 11/10/2022]
Abstract
Obesity-associated inflammation contributes to the development of metabolic diseases. Although brite adipocytes have been shown to ameliorate metabolic parameters in rodents, their origin and differentiation remain to be characterized in humans. Native CD45-/CD34+/CD31- cells have been previously described as human adipocyte progenitors. Using two additional cell surface markers, MSCA1 (tissue nonspecific alkaline phosphatase) and CD271 (nerve growth factor receptor), we are able to partition the CD45-/CD34+/CD31- cell population into three subsets. We establish serum-free culture conditions without cell expansion to promote either white/brite adipogenesis using rosiglitazone, or bone morphogenetic protein 7 (BMP7), or specifically brite adipogenesis using 3-isobuthyl-1-methylxanthine. We demonstrate that adipogenesis leads to an increase of MSCA1 activity, expression of white/brite adipocyte-related genes, and mitochondriogenesis. Using pharmacological inhibition and gene silencing approaches, we show that MSCA1 activity is required for triglyceride accumulation and for the expression of white/brite-related genes in human cells. Moreover, native immunoselected MSCA1+ cells exhibit brite precursor characteristics and the highest adipogenic potential of the three progenitor subsets. Finally, we provided evidence that MSCA1+ white/brite precursors accumulate with obesity in subcutaneous adipose tissue (sAT), and that local BMP7 and inflammation regulate brite adipogenesis by modulating MSCA1 in human sAT. The accumulation of MSCA1+ white/brite precursors in sAT with obesity may reveal a blockade of their differentiation by immune cells, suggesting that local inflammation contributes to metabolic disorders through impairment of white/brite adipogenesis. Stem Cells 2015;33:1277-1291.
Collapse
Affiliation(s)
- David Estève
- Inserm, UMR1048, Team 1, Institute of Metabolic and Cardiovascular Diseases, BP84225, Toulouse Cedex 4, France; Paul Sabatier University, 118, Route de Narbonne, Toulouse Cedex 9, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Grahn THM, Kaur R, Yin J, Schweiger M, Sharma VM, Lee MJ, Ido Y, Smas CM, Zechner R, Lass A, Puri V. Fat-specific protein 27 (FSP27) interacts with adipose triglyceride lipase (ATGL) to regulate lipolysis and insulin sensitivity in human adipocytes. J Biol Chem 2014; 289:12029-12039. [PMID: 24627478 DOI: 10.1074/jbc.m113.539890] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In adipocytes, lipolysis is a highly regulated process involving hormonal signals, lipid droplet-associated proteins, and lipases. The discovery of new lipid droplet-associated proteins added complexity to the current model of lipolysis. In this study, we used cultured human adipocytes to demonstrate that fat-specific protein 27 (FSP27), an abundantly expressed protein in adipocytes, regulates both basal and stimulated lipolysis by interacting with adipose triglyceride lipase (ATGL, also called desnutrin or PNPLA2). We identified a core domain of FSP27, amino acids 120-220, that interacts with ATGL to inhibit its lipolytic function and promote triglyceride storage. We also defined the role of FSP27 in free fatty acid-induced insulin resistance in adipocytes. FSP27 depletion in human adipocytes increased lipolysis and inhibited insulin signaling by decreasing AKT phosphorylation. However, reducing lipolysis by either depletion of ATGL or expression of exogenous full-length FSP27 or amino acids 120-220 protected human adipocytes against the adverse effects of free fatty acids on insulin signaling. In embryonic fibroblasts derived from ATGL KO mice, exogenous free fatty acids did not affect insulin sensitivity. Our results demonstrate a crucial role for FSP27-ATGL interactions in regulating lipolysis, triglyceride accumulation, and insulin signaling in human adipocytes.
Collapse
Affiliation(s)
- Tan Hooi Min Grahn
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Rajween Kaur
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Jun Yin
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz
| | - Vishva Mitra Sharma
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Mi-Jeong Lee
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Yasuo Ido
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Cynthia M Smas
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio 43614
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz
| | - Vishwajeet Puri
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118.
| |
Collapse
|