scholarly journals Protein Tyrosine Phosphatase Activity in Insulin-Resistant RodentPsammomys Obesus

2002 ◽  
Vol 3 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Joseph Meyerovitch ◽  
Yigal Balta ◽  
Ehud Ziv ◽  
Joseph Sack ◽  
Eleazar Shafrir
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Food Deprivation ◽  
Transmembrane Protein ◽  
Tyrosine Phosphatase ◽  
Protein Band ◽  
Liver Fat ◽  
Albino Rats ◽  
Insulin Resistant ◽  
Ptpase Activity

Phosphotyrosine phosphatase (PTPase) activity and its regulation by overnight food deprivation were studied inPsammomys obesus(sand rat), a gerbil model of insulin resistance and nutritionally induced diabetes mellitus. PTPase activity was measured using a phosphopeptide substrate containing a sequence identical to that of the major site of insulin receptor (IR) β-subunit autophosphorylation. The PTPase activity in membrane fractions was 3.5-, 8.3-, and 5.9-fold lower in liver, fat, and skeletal muscle, respectively, compared with corresponding tissues of albino rat.Western blotting of tissue membrane fractions inPsammomysshowed lower PTPase and IR than in albino rats. The density of PTPase transmembrane protein band was 5.5-fold lower in liver and 12-fold lower in adipose tissue. Leukocyte antigen receptor (LAR) and IR were determined by specific immunoblotting and protein bands densitometry and were also found to be 6.3-fold lower in the liver and 22-fold lower in the adipose tissue in the hepatic membrane fractions. Liver cytosolic PTPase activity after an overnight food deprivation in the nondiabeticPsammomysrose 3.7-fold compared with postprandial PTPase activity, but it did not change significantly in diabetic fasted animals. Similar fasting-related changes were detected in the activity of PTPase derived from membrane fraction. In conclusion, the above data demonstrate that despite the insulin resistance,Psammomysis characterized by low level of PTPase activities in membrane and cytosolic fractions in all 3 major insulin responsive tissues, as well as in liver. PTPase activity does not rise in activity as a result of insulin resistance and nutritionally induced diabetes.

scholarly journals Obesity/insulin resistance rather than liver fat increases coagulation factor activities and expression in humans

2017 ◽  
Vol 117 (02) ◽  
pp. 286-294 ◽  
Author(s):  
Susanna Lallukka ◽  
Panu K. Luukkonen ◽  
You Zhou ◽  
Elina Isokuortti ◽  
Marja Leivonen ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Coagulation Factor ◽  
Coagulation Factors ◽  
Liver Fat ◽  
Adipose Tissue Inflammation ◽  
Inflammatory Genes ◽  
Tissue Inflammation ◽  
Hepatic Expression ◽  
Insulin Resistant

SummaryIncreased liver fat may be caused by insulin resistance and adipose tissue inflammation or by the common I148M variant in PNPLA3 at rs738409, which lacks both of these features. We hypothesised that obesity/insulin resistance rather than liver fat increases circulating coagulation factor activities. We measured plasma prothrombin time (PT, Owren method), activated partial thromboplastin time (APTT), activities of several coagulation factors, VWF:RCo and fibrinogen, and D-dimer concentration in 92 subjects divided into groups based on insulin sensitivity [insulin-resistant (‘IR’) versus insulin-sensitive (‘IS’)] and PNPLA3 genotype (PNPLA3148MM/MI vs PNPLA3148II). Liver fat content (1H-MRS) was similarly increased in ‘IR’ (13 ± 1 %) and PNPLA3148MM/MI (12 ± 2 %) as compared to ‘IS’ (6 ± 1 %, p < 0.05) and PNPLA3148II (8 ± 1 %, p < 0.05), respectively. FVIII, FIX, FXIII, fibrinogen and VWF:RCo activities were increased, and PT and APTT shortened in ‘IR’ versus ‘IS’, in contrast to these factors being similar between PNPLA3148MM/MI and PNPLA3148II groups. In subjects undergoing a liver biopsy and entirely lacking the I148M variant, insulin-resistant subjects had higher hepatic expression of F8, F9 and FGG than equally obese insulin-sensitive subjects. Expression of pro-inflammatory genes in adipose tissue correlated positively with PT (% of normal), circulating FVIII, FIX, FXI, VWR:RCo and fibrinogen, and expression of anti-inflammatory genes negatively with PT (%), FIX and fibrinogen. We conclude that obesity/insulin resistance rather than an increase in liver fat is associated with a procoagulant plasma profile. This reflects adipose tissue inflammation and increased hepatic production of coagulation factors and their susceptibility for activation.Supplementary Material to this article is available online at www.thrombosis-online.com.

Alterations of the classic pathway of complement in adipose tissue of obesity and insulin resistance

2007 ◽  
Vol 292 (5) ◽  
pp. E1433-E1440 ◽  
Author(s):  
Jinhui Zhang ◽  
Wendy Wright ◽  
David A. Bernlohr ◽  
Samuel W. Cushman ◽  
Xiaoli Chen
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Epididymal Adipose Tissue ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation ◽  
Insulin Resistant ◽  
Obese Rats ◽  
Initial Activation ◽  
Adipose Cells ◽  
Classic Pathway

Adipose tissue inflammation has recently been linked to the pathogenesis of obesity and insulin resistance. C1 complex comprising three distinct proteins, C1q, C1r, and C1s, involves the key initial activation of the classic pathway of complement and plays an important role in the initiation of inflammatory process. In this study, we investigated adipose expression and regulation of C1 complement subcomponents and C1 activation regulator decorin in obesity and insulin resistance. Expression of C1q in epididymal adipose tissue was increased consistently in ob/ob mice, Zucker obese rats, and high fat-diet-induced obese (HF-DIO) mice. Decorin was found to increase in expression in Zucker obese rats and HF-DIO mice but decrease in ob/ob mice. After TZD administration, C1q and decorin expression was reversed in Zucker obese rats and HF-DIO mice. Increased expression of C1 complement and decorin was observed in both primary adipose and stromal vascular cells isolated from Zucker obese rats. Upregulation of C1r and C1s expression was also perceived in adipose cells from insulin-resistant humans. Furthermore, expression of C1 complement and decorin is dysregulated in TNF-α-induced insulin resistance in 3T3-L1 adipocytes and cultured rat adipose cells as they become insulin resistant after 24-h culture. These data suggests that both adipose and immune cells are the sources for abnormal adipose tissue production of C1 complement and decorin in obesity. Our findings also demonstrate that excessive activation of the classic pathway of complement commonly occurs in obesity, suggesting its possible role in adipose tissue inflammation and insulin resistance.

scholarly journals Visfatin levels in non-obese, obese, and insulin resistant adolescents

2017 ◽  
Vol 56 (5) ◽  
pp. 291
Author(s):  
Indra Ihsan ◽  
Eka Agustia Rini ◽  
Rismawati Yaswir
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Serum Insulin ◽  
Enzyme Linked Immunosorbent Assay ◽  
Model Assessment ◽  
Fasting Serum ◽  
Obese Adolescents ◽  
Insulin Resistant ◽  
Resistant Group ◽  
Visfatin Level

Background Adipose tissue is not merely a site for energy storage, but is also the largest endocrine organ, secreting various adipocytokines. Plasma visfatin, an adipocytokine predominantly secreted from visceral adipose tissue, has insulin-mimetic effects, and has been closely linked to insulin resistance.Objective To compare plasma visfatin levels between obese and non-obese adolescents, as well as between obese adolecents with and without insulin resistance.Methods This cross-sectional study was conducted in students who attended three senior high schools in Padang. Subjects comprised 28 obese and 28 non-obese adolescents. The age of the subjects ranged from 14-18 years. Obesity criteria were based on body mass index (BMI) measurements. Fasting serum glucose level was measured by glucose hexokinase photometry and serum insulin was measured by chemiluminesence immunoassay. Plasma visfatin was measured by enzyme-linked immunosorbent assay (ELISA). The insulin resistance index was estimated from fasting serum insulin and glucose levels using the homeostatic model assessment for insulin resistance (HOMA-IR). Differences in the variables were tested using independent T-test and Mann-Whitney test, depending on the distribution of the variables.Results The mean plasma visfatin level was significantly higher in the obese than in the control group [2.55 (SD 1.54) vs. 1.61 (SD 0.64) ng/mL, respectively; (P=0.005)]. The insulin resistant group had significantly higher mean plasma visfatin level than the non-resistant group [3.61 (SD 1.59) vs. 1.96 (SD 1.18) ng/mL, respectively; (P=0.004)].Conclusion Obese adolescents with insulin resistance have signifcantly higher plasma visfatin levels compared to those without insulin resistance.

scholarly journals Collagen 24 α1 Is Increased in Insulin-Resistant Skeletal Muscle and Adipose Tissue

2020 ◽  
Vol 21 (16) ◽  
pp. 5738
Author(s):  
Xiong Weng ◽  
De Lin ◽  
Jeffrey T. J. Huang ◽  
Roland H. Stimson ◽  
David H. Wasserman ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Insulin Resistant ◽  
Global View ◽  
Novel Association ◽  
Visceral Adipose ◽  
Subcutaneous Adipose

Aberrant extracellular matrix (ECM) remodelling in muscle, liver and adipose tissue is a key characteristic of obesity and insulin resistance. Despite its emerging importance, the effective ECM targets remain largely undefined due to limitations of current approaches. Here, we developed a novel ECM-specific mass spectrometry-based proteomics technique to characterise the global view of the ECM changes in the skeletal muscle and liver of mice after high fat (HF) diet feeding. We identified distinct signatures of HF-induced protein changes between skeletal muscle and liver where the ECM remodelling was more prominent in the muscle than liver. In particular, most muscle collagen isoforms were increased by HF diet feeding whereas the liver collagens were differentially but moderately affected highlighting a different role of the ECM remodelling in different tissues of obesity. Moreover, we identified a novel association between collagen 24α1 and insulin resistance in the skeletal muscle. Using quantitative gene expression analysis, we extended this association to the white adipose tissue. Importantly, collagen 24α1 mRNA was increased in the visceral adipose tissue, but not the subcutaneous adipose tissue of obese diabetic subjects compared to lean controls, implying a potential pathogenic role of collagen 24α1 in obesity and type 2 diabetes.

Effects of rosiglitazone on gene expression in subcutaneous adipose tissue in highly active antiretroviral therapy-associated lipodystrophy

2004 ◽  
Vol 286 (6) ◽  
pp. E941-E949 ◽  
Author(s):  
Jussi Sutinen ◽  
Katja Kannisto ◽  
Elena Korsheninnikova ◽  
Rachel M. Fisher ◽  
Ewa Ehrenborg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Insulin Resistance ◽  
Adipose Tissue ◽  
Highly Active Antiretroviral Therapy ◽  
Subcutaneous Adipose Tissue ◽  
Binding Protein ◽  
Lipid Binding ◽  
Liver Fat ◽  
Highly Active ◽  
Subcutaneous Adipose

Highly active antiretroviral therapy (HAART) has improved the prognosis of human immunodeficiency virus (HIV)-infected patients but is associated with severe adverse events, such as lipodystrophy and insulin resistance. Rosiglitazone did not increase subcutaneous fat in patients with HAART-associated lipodystrophy (HAL) in a randomized, double-blind, placebo-controlled trial, although it attenuated insulin resistance and decreased liver fat content. The aim of this study was to examine effects of rosiglitazone on gene expression in subcutaneous adipose tissue in 30 patients with HAL. The mRNA concentrations in subcutaneous adipose tissue were measured using real-time PCR. Twenty-four-week treatment with rosiglitazone (8 mg/day) compared with placebo significantly increased the expression of adiponectin, peroxisome proliferator-activated receptor-γ (PPARγ), and PPARγ coactivator 1 and decreased IL-6 expression. Expression of other genes involved in lipogenesis, fatty acid metabolism, or glucose transport, such as acyl-CoA synthase, adipocyte lipid-binding protein, CD45, fatty acid transport protein-1 and -4, GLUT1, GLUT4, keratinocyte lipid-binding protein, lipoprotein lipase, PPARδ, and sterol regulatory element-binding protein-1c, remained unchanged. Rosiglitazone also significantly increased serum adiponectin concentration. The change in serum adiponectin concentration was inversely correlated with the change in fasting serum insulin concentration and liver fat content. In conclusion, rosiglitazone induced significant changes in gene expression in subcutaneous adipose tissue and ameliorated insulin resistance in patients with HAL. Increased expression of adiponectin might have mediated most of the favorable insulin-sensitizing effects of rosiglitazone in these patients.

scholarly journals Inhibition of Protein Tyrosine Phosphatase-1B with Antisense Oligonucleotides Improves Insulin Sensitivity and Increases Adiponectin Concentrations in Monkeys

Endocrinology ◽  
2009 ◽  
Vol 150 (4) ◽  
pp. 1670-1679 ◽  
Author(s):  
Michael M. Swarbrick ◽  
Peter J. Havel ◽  
Arthur A. Levin ◽  
Andrew A. Bremer ◽  
Kimber L. Stanhope ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Protein Tyrosine Phosphatase ◽  
Antisense Oligonucleotides ◽  
Tyrosine Phosphatase ◽  
Ptp 1B ◽  
Insulin Responses

Protein tyrosine phosphatase (PTP)-1B antagonizes insulin signaling and is a potential therapeutic target for insulin resistance associated with obesity and type 2 diabetes. To date, studies of PTP-1B have been limited by the availability of specific antagonists; however, treatment of rodents with antisense oligonucleotides (ASOs) directed against PTP-1B improves insulin sensitivity, inhibits lipogenic gene expression, and reduces triglyceride accumulation in liver and adipose tissue. Here we investigated ASO-mediated PTP-1B inhibition in primates. First, PTP-1B ASO (ISIS 113715) dose-dependently inhibited PTP-1B mRNA and protein expression in cultured monkey hepatocytes. Subcutaneous administration of ISIS 113715 reduced PTP-1B mRNA expression in liver and adipose tissue of normal-weight monkeys by 40–50% and improved insulin sensitivity during an iv glucose tolerance test (IVGTT). In obese, insulin-resistant rhesus monkeys, treatment with 20 mg/kg ISIS 113715 for 4 wk reduced fasting concentrations of insulin and glucose and reduced insulin responses during an IVGTT. In these animals, adiponectin concentrations were also increased by 70%, most of which was an increase of high-molecular-weight oligomers. These effects were not observed in monkeys on a lower, dose-escalation regimen (1–10 mg/kg over 9 wk). Overall, the increase of adiponectin concentrations during ISIS 113715 treatment was correlated with the lowering of insulin responses during IVGTT (r = −0.47, P = 0.042). These results indicate that inhibition of PTP-1B with ASOs such as ISIS 113715 may be a viable approach for the treatment and prevention of obesity-associated insulin resistance and type 2 diabetes because they potently increase adiponectin concentrations in addition to improving insulin sensitivity.

scholarly journals Role of patatin-like phospholipase domain-containing 3 gene for hepatic lipid content and insulin resistance in diabetes

2020 ◽  
Author(s):  
Oana P. Zaharia ◽  
Klaus Strassburger ◽  
Birgit Knebel ◽  
Yuliya Kupriyanova ◽  
Yanislava Karusheva ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Lipid Content ◽  
Whole Body ◽  
Hepatic Lipid ◽  
Insulin Resistant ◽  
Increased Risk ◽  
Glucose Tolerant ◽  
Hepatic Lipid Content

<a><b>Objective</b></a>: The rs738409(G) single-nucleotide polymorphism (SNP) in the patatin-like phospholipase domain-containing 3 (<i>PNPLA3</i>) gene associates with increased risk and progression of nonalcoholic fatty liver disease (NAFLD). As the recently-described severe insulin-resistant diabetes (SIRD) cluster specifically relates to NAFLD, this study examined whether this SNP differently associates with hepatic lipid content (HCL) and insulin sensitivity in recent-onset diabetes mellitus. <p><b>Research Design and Methods</b>: A total of 917 participants of the German Diabetes Study underwent genotyping, hyperinsulinemic-euglycemic clamps with stable isotopic tracer dilution and magnetic resonance spectroscopy. </p> <p><b>Results:</b> The G allele associated positively with HCL (β=0.36, p<0.01), independent of age, sex and BMI across the whole cohort, but not in the individual clusters. SIRD exhibited lowest whole-body insulin sensitivity compared to severe insulin-deficient (SIDD), moderate obesity-related (MOD), moderate age-related (MARD) and severe autoimmune diabetes clusters (SAID; all p<0.001). Interestingly, SIRD presented with higher prevalence of the rs738409(G) SNP compared to other clusters and the glucose-tolerant control group (p<0.05). HCL was higher in SIRD [13.6 (5.8;19.1)%] compared to MOD [6.4 (2.1;12.4)%, p<0.05], MARD [3.0 (1.0;7.9)%, p<0.001], SAID [0.4 (0.0;1.5)%, p<0.001] and the glucose tolerant group [0.9 (0.4;4.9)%, p<0.001]. Although the <i>PNPLA3</i> polymorphism did not directly associate with whole-body insulin sensitivity in SIRD, the G allele carriers had higher circulating free fatty acid concentrations and greater adipose-tissue insulin resistance compared to non-carriers (both p<0.001).</p> <b>Conclusions:</b> Members of the severe insulin resistant diabetes cluster are more frequently carriers of the rs738409(G) variant. The SNP-associated adipose-tissue insulin resistance and excessive lipolysis may contribute to their NAFLD.

scholarly journals Changes in FGF21 Serum Concentrations and Liver mRNA Expression in an Experimental Model of Complete Lipodystrophy and Insulin-Resistant Diabetes

2014 ◽  
pp. 483-490 ◽  
Author(s):  
A. ŠPOLCOVÁ ◽  
M. HOLUBOVÁ ◽  
B. MIKULÁŠKOVÁ ◽  
V. NAGELOVÁ ◽  
A. ŠTOFKOVÁ ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Mrna Expression ◽  
Plasma Levels ◽  
Glucose Transporter ◽  
Liver Fat ◽  
Fibroblast Growth Factor 21 ◽  
Glucose Transporter 1 ◽  
Insulin Resistant

Patients with obesity and type 2 diabetes often display high levels of the anti-diabetic factor fibroblast growth factor-21 (FGF21), suggesting that the overproduction of FGF21 may result from increased adiposity in an attempt by white adipose tissue (WAT) to counteract insulin resistance. However, the production of FGF21 diabetes in the absence of WAT has not been examined. In this study, we investigated the effects of lipodystrophy in A-ZIP F-1 mice on FGF21 production in relation to diabetes. A-ZIP F-1 mice displayed high FGF21 plasma levels resulting from enhanced FGF21 mRNA expression in the liver. Concomitant enhancement of FGF21 receptor (FGFR1) and glucose transporter 1 (GLUT-1) mRNA expression was observed in the muscles of A-ZIP F-1 mice. Furthermore, the activation of hypothalamic NPY and AgRP mRNA expression positively correlated with plasma levels of FGF21 but not active ghrelin. Our study demonstrates that an increased FGF21 plasma level in lipodystrophic A-ZIP F-1 mice results mainly from up-regulated liver production but does not suffice to overcome the lipodystrophy-induced severe type 2-diabetes and insulin resistance in the liver linked to the augmented liver fat deposition.

Normal Akt/PKB with reduced PI3K activation in insulin-resistant mice

2001 ◽  
Vol 281 (6) ◽  
pp. E1249-E1254 ◽  
Author(s):  
Samuel T. Nadler ◽  
Jonathan P. Stoehr ◽  
Mary E. Rabaglia ◽  
Kathryn L. Schueler ◽  
Morris J. Birnbaum ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Glucose Uptake ◽  
Phosphatidylinositol 3 Kinase ◽  
Insulin Resistant ◽  
Experimental Systems ◽  
Pi3k Activity ◽  
Pi3k Activation

Insulin stimulates muscle and adipose tissue to absorb glucose through a signaling cascade that is incompletely understood. Insulin resistance, the inability of insulin to appropriately stimulate glucose uptake, is a hallmark of type 2 diabetes mellitus. The development of experimental systems that model human insulin resistance is important in elucidating the defects responsible for the development of type 2 diabetes. When two strains of mice, BTBR and C57BL/6J (B6), are crossed, the resultant male offspring (BtB6) demonstrate insulin resistance in muscle tissue. Here, we report an insulin resistance phenotype in adipose tissue from lean, nondiabetic BtB6 mice similar to that observed in human muscle. Adipocytes isolated from insulin-resistant male mice display 65% less insulin-stimulated glucose uptake compared with insulin-sensitive female mice. Similarly, adipocytes from insulin-resistant mice have diminished insulin-stimulated IRS-1 phosphorylation and phosphatidylinositol 3-kinase (PI3K) activation. However, normal activation of protein kinase B (Akt/PKB) by insulin is observed. Thus BtB6 mice demonstrate the dissociation of insulin-stimulated PI3K activity and Akt/PKB activation and represent a useful model to investigate the causes of insulin resistance in humans.

Investigation of insulin resistance through a multiorgan microfluidic organ-on-chip

2021 ◽  
Author(s):  
Nida Tanataweethum ◽  
Allyson Trang ◽  
Chaeeun Lee ◽  
Jhalak Mehta ◽  
Neha Patel ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Lipid Synthesis ◽  
Hepatic Insulin Resistance ◽  
Insulin Resistant ◽  
Brown Adipose ◽  
Hepatic Glucose ◽  
On Chip ◽  
Adipose Organ

Abstract The development of hepatic insulin resistance (IR) is a critical factor in developing type 2 diabetes (T2D), where insulin fails to inhibit hepatic glucose production but retains its capacity to promote hepatic lipogenesis. Improving insulin sensitivity can be effective in preventing and treating T2D. However, selective control of glucose and lipid synthesis has been difficult. It is known that excess white adipose tissue is detrimental to insulin sensitivity, whereas brown adipose tissue transplantation can restore it in diabetic mice. However, challenges remain in our understanding of liver-adipose communication because the confounding effects of hypothalamic regulation of metabolic function cannot be ruled out in previous studies. There is a lack of in vitro models that use primary cells to study cellular-crosstalk under insulin resistant conditions. Building upon our previous work on the microfluidic primary liver and adipose organ-on-chips, we report for the first time the development of integrated insulin resistant liver-adipose (white and brown) organ-on-chip. The design of the microfluidic device was carried out using computational fluid dynamics; the experimental studies were conducted by carrying out detailed biochemical analysis RNA-seq analysis on both cell types. Further, we tested the hypothesis that brown adipocytes regulated both hepatic insulin sensitivity and lipogenesis. Our results show effective co-modulation of hepatic glucose and lipid synthesis through a platform for identifying potential therapeutics for IR and diabetes.

Sign in / Sign up

Export Citation Format

Share Document