scholarly journals Simple Fabrication of Adipocyte Cell Chip Using Micropatterning

2016 ◽  
Vol 54 (2) ◽  
pp. 223-228 ◽  
Author(s):  
Gi Yong Kim ◽  
Heon-Ho Jeong ◽  
Chang-Soo Lee ◽  
Changhyun Roh
Keyword(s):  
Cell Chip ◽  
Adipocyte Cell

scholarly journals Expression and compartmentalization of caveolin in adipose cells: coordinate regulation with and structural segregation from GLUT4.

1995 ◽  
Vol 129 (4) ◽  
pp. 999-1006 ◽  
Author(s):  
K V Kandror ◽  
J M Stephens ◽  
P F Pilch
Keyword(s):  
Cell Surface ◽  
Glucose Transporter ◽  
Buoyant Density ◽  
Fat Cells ◽  
Structural Protein ◽  
Coordinate Regulation ◽  
Rat Adipocytes ◽  
Transport Vesicles ◽  
Adipocyte Cell ◽  
Insulin Dependent

Native rat adipocytes and the mouse adipocyte cell line, 3T3-L1, possess transport vesicles of apparently uniform composition and size which translocate the tissue-specific glucose transporter isoform, GLUT4, from an intracellular pool to the cell surface in an insulin-sensitive fashion. Caveolin, the presumed structural protein of caveolae, has also been proposed to function in vesicular transport. Thus, we studied the expression and subcellular distribution of caveolin in adipocytes. We found that rat fat cells express the highest level of caveolin protein of any tissue studied, and caveolin is also expressed at high levels in cardiac muscle, another tissue possessing insulin responsive GLUT4 translocation. Both proteins are absent from 3T3-L1 fibroblasts and undergo a dramatic coordinate increase in expression upon differentiation of these cells into adipocytes. However, unlike GLUT4 in rat adipocytes not exposed to insulin, the majority of caveolin is present in the plasma membrane. In native rat adipocytes, intracellular GLUT4 and caveolin reside in vesicles practically indistinguishable by their size and buoyant density in sucrose gradients, and both proteins show insulin-dependent translocation to the cell surface. However, by immunoadsorption of GLUT4-containing vesicles with anti-GLUT4 antibody, we show that these vesicles have no detectable caveolin, and therefore, this protein is present in a distinct vesicle population. Thus, caveolin has no direct structural relation to the organization of the intracellular glucose transporting machinery in fat cells.

Abstract 3672: Loss of Perivascular Adipocyte Paracrine Function Leads to Increased Vascular Tone and Glucose Intolerance in Hypertension

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Kaivan Khavandi ◽  
Adam Greenstein ◽  
Sarah Withers ◽  
Kazuhiko Sonoyama ◽  
Sarah Lewis ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Metabolic Syndrome ◽  
Adipose Tissue ◽  
Vascular Tone ◽  
Tnf Alpha ◽  
Perivascular Adipose Tissue ◽  
The Metabolic Syndrome ◽  
Adipocyte Cell ◽  
Therapeutic Opportunity

In order to investigate the contribution of perivascular adipose tissue (PVAT) to arterial function, a total of 55 small arteries harvested from 35 skin biopsies of patients with Metabolic Syndrome and matched controls were mounted as ring preparations in a wire myograph. Contractility to cumulative doses of Norepinephrine in the presence or absence of PVAT showed an anticontractile effect in arteries from healthy volunteers (p=0.009), which was lost in patients with Metabolic Syndrome. Bioassay studies confirmed that PVAT releases a hydrophilic anticontractile factor in health, which is absent in obesity. Using a soluble fragment of the human Type 1 receptor, we identified that the anticontractile factor was adiponectin, which is the sole mediator of vasodilation, acting by increasing endothelial bioavailability of nitric oxide. Significant endothelial dysfunction was observed in patients with Metabolic Syndrome (p<0.001). Quantitative image analysis of adipose tissue revealed significantly increased adipocyte cell size in patients with Metabolic Syndrome, compared with healthy controls (p<0.006). There was immunohistochemical evidence of inflammation with upregulation of TNF-alpha receptor 1 in these patients (p<0.001). Application of exogenous TNF-alpha abolished the anticontractile effect of PVAT by reducing adiponectin bioavailability. Oxidative stress also induced by cytokines TNF-alpha and IL-6 but not IL-1, reduced adiponectin production from PVAT and increased basal tone. When the obese microenvironment was replicated in vitro by inflicting hypoxia on PVAT, adiponectin activity was lost but then rescued by incubation with cytokine antagonists. Further application of the adiponectin receptor fragment abolished PVAT relaxation. We conclude that in healthy arteries, PVAT releases adiponectin which reduces vascular tone. In obesity, this is lost by a cascade of adipocyte hypertrophy, hypoxia, inflammation and oxidative stress. The resulting vasoconstriction contributes to hypertension, hypertriglyceridaemia and insulin resistance. Direct targeting of adiponectin release from PVAT therefore provides a novel therapeutic opportunity in the Metabolic Syndrome.

scholarly journals The lipoprotein lipase of white adipose tissue. Changes in the adipocyte cell-surface content of enzyme in response to extracellular effectors in vitro

1986 ◽  
Vol 238 (1) ◽  
pp. 239-246 ◽  
Author(s):  
A A Al-Jafari ◽  
A Cryer
Keyword(s):  
Protein Synthesis ◽  
Cell Surface ◽  
Lipoprotein Lipase ◽  
Protein Transport ◽  
Independent Effect ◽  
Adipocyte Cell ◽  
Tissue Changes ◽  
Insulin Dependent ◽  
Hormonal Action

An indirect labelled-second-antibody cellular immunoassay for adipocyte surface lipoprotein lipase was used to assess the changes that occurred during the incubation of cells in the presence and absence of effectors. In the absence of any specific effectors, the amount of immunodetectable lipoprotein lipase present at the surface of adipocytes remained constant throughout the 4 h incubation period at 37 degrees C. Under such conditions total cellular enzyme activity also remained constant, with no activity appearing in the medium. In the presence of heparin, cell-surface immunodetectable lipoprotein lipase increased by up to 20%, whereas in the presence of cycloheximide they decreased by up to 60%. Thus the obvious turnover of enzyme from this cell-surface site was found to be relatively rapid and dependent for its replenishment, at least in part, on protein synthesis. In the presence of insulin alone, a substantial increase in cell-surface lipoprotein lipase protein occurred, only part of which was dependent on protein synthesis. The total cellular activity of lipoprotein lipase was unaffected by the presence of insulin. The insulin-dependent increase in cell-surface enzyme was potentiated somewhat in the presence of dexamethasone, which was not shown to exert any independent effect. Glucagon, adrenaline and theophylline all produced a significant decline in the cell-surface immunodetectable lipoprotein lipase, which in the case examined (adrenaline) was partially additive with regard to the independent effect of cycloheximide. Cell-surface immunodetectable lipoprotein lipase amounts were decreased significantly when cells were incubated in the presence of either colchicine or tunicamycin. The concerted way in which cell-surface lipoprotein lipase altered during the incubations of adipocytes in the presence of effectors suggested that the translocation of enzyme to and from this cellular site was dependent on hormonal action and the integrity of intracellular protein-transport mechanisms.

scholarly journals D-Chiro-Inositol Regulates Insulin Signaling in Human Adipocytes

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria Magdalena Montt-Guevara ◽  
Michele Finiguerra ◽  
Ilaria Marzi ◽  
Tiziana Fidecicchi ◽  
Amerigo Ferrari ◽  
...  
Keyword(s):  
Insulin Signaling ◽  
Glucose Transporter ◽  
Polycystic Ovary ◽  
Mitochondrial Respiratory Chain ◽  
Glycogen Storage ◽  
Metabolic Dysfunction ◽  
Human Adipocytes ◽  
Direct Role ◽  
Secondary Messenger ◽  
Adipocyte Cell

D-Chiro-Inositol (D-Chiro-Ins) is a secondary messenger in the insulin signaling pathway. D-Chiro-Ins modulates insulin secretion, the mitochondrial respiratory chain, and glycogen storage. Due to these actions D-Chiro-Ins has been proposed to correct defective insulin function in a variety of conditions characterized by metabolic dysfunction, such as polycystic ovary syndrome (PCOS), obesity, gestational diabetes and fat accumulation at menopause. Since it is unclear whether D-Chiro-Ins directly acts on adipocytes, we aimed to study D-Chiro-Ins’s actions on adipocyte viability, proliferation, differentiation, and insulin-related protein expression using a human adipocyte cell line derived from Simpson–Golabi–Behmel Syndrome (SGBS) which fully differentiates to mature adipocytes. Throughout differentiation, cells were treated with D-Chiro-Ins, 17β-estradiol (E2) or Insulin. Cell viability and proliferation were not affected by D-Chiro-Ins, then D-Chiro-Ins promoted cell differentiation only during the final days of the process, while E2 enhanced it from the first phases. D-Chiro-Ins stimulated lipid storage and the production of big lipid droplets, thus reducing the content of free fatty acids. We also found that D-Chiro-Ins, either alone or in combination with insulin and E2 increased the expression and activation of insulin receptor substrate-1 (IRS1) and glucose transporter type 4 (GLUT4). In conclusion, this work shows that D-Chiro-Ins plays a direct role in the differentiation and in the function of human adipocytes, where it synergizes with insulin and estrogen through the recruitment of signal transduction pathways involved in lipid and glucose storage. These findings give clear insights to better understand the actions of D-Chiro-Ins on fat metabolism in women in physiology and in a variety of diseases.

scholarly journals BET bromodomain proteins regulate enhancer function during adipogenesis

2018 ◽  
Vol 115 (9) ◽  
pp. 2144-2149 ◽  
Author(s):  
Jonathan D. Brown ◽  
Zachary B. Feldman ◽  
Sean P. Doherty ◽  
Jaime M. Reyes ◽  
Peter B. Rahl ◽  
...  
Keyword(s):  
Gene Expression ◽  
De Novo ◽  
Critical Role ◽  
Regulatory Elements ◽  
Developmental Transitions ◽  
Adipocyte Cell ◽  
Bromodomain Proteins ◽  
Enhancer Function ◽  
Distal Regulatory Elements ◽  
Expression Program

Developmental transitions are guided by master regulatory transcription factors. During adipogenesis, a transcriptional cascade culminates in the expression of PPARγ and C/EBPα, which orchestrate activation of the adipocyte gene expression program. However, the coactivators controlling PPARγ and C/EBPα expression are less well characterized. Here, we show the bromodomain-containing protein, BRD4, regulates transcription of PPARγ and C/EBPα. Analysis of BRD4 chromatin occupancy reveals that induction of adipogenesis in 3T3L1 fibroblasts provokes dynamic redistribution of BRD4 to de novo super-enhancers proximal to genes controlling adipocyte differentiation. Inhibition of the bromodomain and extraterminal domain (BET) family of bromodomain-containing proteins impedes BRD4 occupancy at these de novo enhancers and disrupts transcription of Pparg and Cebpa, thereby blocking adipogenesis. Furthermore, silencing of these BRD4-occupied distal regulatory elements at the Pparg locus by CRISPRi demonstrates a critical role for these enhancers in the control of Pparg gene expression and adipogenesis in 3T3L1s. Together, these data establish BET bromodomain proteins as time- and context-dependent coactivators of the adipocyte cell state transition.

Lipoprotein lipase binding to adipocytes: evidence for the presence of a heparin-sensitive binding protein

1993 ◽  
Vol 265 (6) ◽  
pp. E880-E888 ◽  
Author(s):  
A. Sasaki ◽  
P. Sivaram ◽  
I. J. Goldberg
Keyword(s):  
Cell Surface ◽  
Lipoprotein Lipase ◽  
Binding Protein ◽  
Surface Protein ◽  
Surface Binding ◽  
Cell Membrane Proteins ◽  
Adipocyte Cell ◽  
Capillary Endothelial Cells ◽  
Fold Excess ◽  
Ligand Blot

Lipoprotein lipase (LPL) is synthesized by adipocytes, associated with the cell surface, and released from the cells when they are treated with heparin. Release of LPL from the adipocyte is required for LPL to migrate to its physiological site of action on the luminal surface of capillary endothelial cells. To better understand this process, we studied the interaction of LPL with adipocyte cell membrane proteins. With the use of a ligand blot method, LPL specifically bound to a heparin-releasable, 116-kDa protein on mouse-derived brown fat adipose cell (BFC-1 beta) and rat adipocyte membranes. A 116-kDa cell surface protein was metabolically labeled with [35S]methionine and bound to LPL-Sepharose. This suggested that the LPL-binding protein was synthesized by the cells. When BFC-1 beta were treated with heparin to eliminate heparin-sensitive cell surface binding sites, LPL binding to the cells decreased and release of newly synthesized LPL activity increased. 125I-labeled LPL binding to control cells was reduced (> 70%) by a 50-fold excess of unlabeled LPL. The residual LPL binding to heparin-treated cells was, however, not decreased by the addition of unlabeled LPL. These data imply that specific adipocyte surface LPL binding involves heparin-sensitive sites. We hypothesize that the heparin-releasable, 116-kDa LPL-binding protein mediates specific LPL binding to adipocytes and that LPL activity within adipose tissue is regulated, in part, by the interaction of LPL with this binding protein.

scholarly journals An MRM-Based Multiplexed Quantification Assay for Human Adipokines and Apolipoproteins

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 775 ◽  
Author(s):  
Laura Krieg ◽  
Alexandra Schaffert ◽  
Matthias Kern ◽  
Kathrin Landgraf ◽  
Martin Wabitsch ◽  
...  
Keyword(s):  
Serum Proteins ◽  
Multiple Reaction Monitoring ◽  
Normal Weight ◽  
The Body ◽  
Serum Samples ◽  
Human Adipocyte ◽  
Disease Mechanisms ◽  
Adipocyte Cell ◽  
Functional Analyses ◽  
Culture Supernatants

Adipokines and apolipoproteins are key regulators and potential biomarkers in obesity and associated diseases and their quantitative assessment is crucial for functional analyses to understand disease mechanisms. Compared to routinely used ELISAs, multiple reaction monitoring (MRM)-based mass spectrometry allows multiplexing and detection of proteins for which antibodies are not available. Thus, we established an MRM method to quantify 9 adipokines and 10 apolipoproteins in human serum. We optimized sample preparation by depleting the two most abundant serum proteins for improved detectability of low abundant proteins. Intra-day and inter-day imprecision were below 16.5%, demonstrating a high accuracy. In 50 serum samples from participants with either normal weight or obesity, we quantified 8 adipokines and 10 apolipoproteins. Significantly different abundances were observed for five adipokines (adipsin, adiponectin, chemerin, leptin, vaspin) and four apolipoproteins (apo-B100/-C2/-C4/-D) between the body mass index (BMI) groups. Additionally, we applied our MRM assay to serum samples from normal weight children and human adipocyte cell culture supernatants to proof the feasibility for large cohort studies and distinct biological matrices. In summary, this multiplexed assay facilitated the investigation of relationships between adipokines or apolipoproteins and phenotypes or clinical parameters in large cohorts, which may contribute to disease prediction approaches in the future.

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