scholarly journals Annexins in Adipose Tissue: Novel Players in Obesity

2019 ◽  
Vol 20 (14) ◽  
pp. 3449 ◽  
Author(s):  
Thomas Grewal ◽  
Carlos Enrich ◽  
Carles Rentero ◽  
Christa Buechler
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Glucose Transporter ◽  
Metabolic Diseases ◽  
Cell Metabolism ◽  
Fatty Acid Uptake ◽  
Membrane Microdomains ◽  
Acid Uptake ◽  
Dependent Manner ◽  
Membrane Microdomain

Obesity and the associated comorbidities are a growing health threat worldwide. Adipose tissue dysfunction, impaired adipokine activity, and inflammation are central to metabolic diseases related to obesity. In particular, the excess storage of lipids in adipose tissues disturbs cellular homeostasis. Amongst others, organelle function and cell signaling, often related to the altered composition of specialized membrane microdomains (lipid rafts), are affected. Within this context, the conserved family of annexins are well known to associate with membranes in a calcium (Ca2+)- and phospholipid-dependent manner in order to regulate membrane-related events, such as trafficking in endo- and exocytosis and membrane microdomain organization. These multiple activities of annexins are facilitated through their diverse interactions with a plethora of lipids and proteins, often in different cellular locations and with consequences for the activity of receptors, transporters, metabolic enzymes, and signaling complexes. While increasing evidence points at the function of annexins in lipid homeostasis and cell metabolism in various cells and organs, their role in adipose tissue, obesity and related metabolic diseases is still not well understood. Annexin A1 (AnxA1) is a potent pro-resolving mediator affecting the regulation of body weight and metabolic health. Relevant for glucose metabolism and fatty acid uptake in adipose tissue, several studies suggest AnxA2 to contribute to coordinate glucose transporter type 4 (GLUT4) translocation and to associate with the fatty acid transporter CD36. On the other hand, AnxA6 has been linked to the control of adipocyte lipolysis and adiponectin release. In addition, several other annexins are expressed in fat tissues, yet their roles in adipocytes are less well examined. The current review article summarizes studies on the expression of annexins in adipocytes and in obesity. Research efforts investigating the potential role of annexins in fat tissue relevant to health and metabolic disease are discussed.

Isotope tracer measures of meal fatty acid metabolism: reproducibility and effects of the menstrual cycle

2005 ◽  
Vol 288 (3) ◽  
pp. E547-E555 ◽  
Author(s):  
Ana Paola Uranga ◽  
James Levine ◽  
Michael Jensen
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Menstrual Cycle ◽  
Dietary Fat ◽  
Fatty Acid Uptake ◽  
Upper Body ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
Lower Body

Oxidation and adipose tissue uptake of dietary fat can be measured by adding fatty acid tracers to meals. These studies were conducted to measure between-study variability of these types of experiments and assess whether dietary fatty acids are handled differently in the follicular vs. luteal phase of the menstrual cycle. Healthy normal-weight men ( n = 12) and women ( n = 12) participated in these studies, which were block randomized to control for study order, isotope ([3H]triolein vs. [14C]triolein), and menstrual cycle. Energy expenditure (indirect calorimetry), meal fatty acid oxidation, and meal fatty acid uptake into upper body and lower body subcutaneous fat (biopsies) 24 h after the experimental meal were measured. A greater portion of meal fatty acids was stored in upper body subcutaneous adipose tissue (24 ± 2 vs. 16 ± 2%, P < 0.005) and lower body fat (12 ± 1 vs. 7 ± 1%, P < 0.005) in women than in men. Meal fatty acid oxidation (3H2O generation) was greater in men than in women (52 ± 3 vs. 45 ± 2%, P = 0.04). Leg adipose tissue uptake of meal fatty acids was 15 ± 2% in the follicular phase of the menstrual cycle and 10 ± 1% in the luteal phase ( P = NS). Variance in meal fatty acid uptake was somewhat ( P = NS) greater in women than in men, although menstrual cycle factors did not contribute significantly. We conclude that leg uptake of dietary fat is slightly more variable in women than in men, but that there are no major effects of menstrual cycle on meal fatty acid disposal.

scholarly journals Lipid storage by adipose tissue macrophages regulates systemic glucose tolerance

2014 ◽  
Vol 307 (4) ◽  
pp. E374-E383 ◽  
Author(s):  
Myriam Aouadi ◽  
Pranitha Vangala ◽  
Joseph C. Yawe ◽  
Michaela Tencerova ◽  
Sarah M. Nicoloro ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Glucose Tolerance ◽  
Glucose Intolerance ◽  
Fatty Acid Uptake ◽  
Foam Cell Formation ◽  
Acid Uptake ◽  
Obese Mice ◽  
Adipose Tissue Macrophages

Proinflammatory pathways in adipose tissue macrophages (ATMs) can impair glucose tolerance in obesity, but ATMs may also be beneficial as repositories for excess lipid that adipocytes are unable to store. To test this hypothesis, we selectively targeted visceral ATMs in obese mice with siRNA against lipoprotein lipase (LPL), leaving macrophages within other organs unaffected. Selective silencing of ATM LPL decreased foam cell formation in visceral adipose tissue of obese mice, consistent with a reduced supply of fatty acids from VLDL hydrolysis. Unexpectedly, silencing LPL also decreased the expression of genes involved in fatty acid uptake (CD36) and esterification in ATMs. This deficit in fatty acid uptake capacity was associated with increased circulating serum free fatty acids. Importantly, ATM LPL silencing also caused a marked increase in circulating fatty acid-binding protein-4, an adipocyte-derived lipid chaperone previously reported to induce liver insulin resistance and glucose intolerance. Consistent with this concept, obese mice with LPL-depleted ATMs exhibited higher hepatic glucose production from pyruvate and glucose intolerance. Silencing CD36 in ATMs also promoted glucose intolerance. Taken together, the data indicate that LPL secreted by ATMs enhances their ability to sequester excess lipid in obese mice, promoting systemic glucose tolerance.

scholarly journals Interactions between CD36 and global intestinal alkaline phosphatase in mouse small intestine and effects of high-fat diet

2011 ◽  
Vol 301 (6) ◽  
pp. R1738-R1747 ◽  
Author(s):  
Matthew Lynes ◽  
Sonoko Narisawa ◽  
José Luis Millán ◽  
Eric P. Widmaier
Keyword(s):  
Fatty Acid ◽  
High Fat Diet ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Dependent Manner ◽  
High Fat ◽  
Intestinal Alkaline Phosphatase ◽  
Mouse Small Intestine ◽  
Mouse Intestine ◽  
Plasma Leptin

The mechanisms of the saturable component of long-chain fatty acid (LCFA) transport across the small intestinal epithelium and its regulation by a high-fat diet (HFD) are uncertain. It is hypothesized here that the putative fatty acid translocase/CD36 and intestinal alkaline phosphatases (IAPs) function together to optimize LCFA transport. Phosphorylated CD36 (pCD36) was expressed in mouse enterocytes and dephosphorylated by calf IAP (CIAP). Uptake of fluorescently tagged LCFA into isolated enteroctyes was increased when cells were treated with CIAP; this was blocked with a specific CD36 inhibitor. pCD36 colocalized in enterocytes with the global IAP (gIAP) isozyme and, specifically, coimmunoprecipitated with gIAP, but not the duodenal-specific isozyme (dIAP). Purified recombinant gIAP dephosphorylated immunoprecipitated pCD36, and antiserum to gIAP decreased initial LCFA uptake in enterocytes. Body weight, adiposity, and plasma leptin and triglycerides were significantly increased in HFD mice compared with controls fed a normal-fat diet. HFD significantly increased immunoreactive CD36 and gIAP, but not dIAP, in jejunum, but not duodenum. Uptake of LCFA was increased in a CD36-dependent manner in enterocytes from HFD mice. It is concluded that CD36 exists in its phosphorylated and dephosphorylated states in mouse enterocytes, that pCD36 is a substrate of gIAP, and that dephosphorylation by IAPs results in increased LCFA transport capability. HFD upregulates CD36 and gIAP in parallel and enhances CD36-dependent fatty acid uptake. The interactions between these proteins may be important for efficient fat transport in mouse intestine, but whether the changes in gIAP and CD36 in enterocytes contribute to HFD-induced obesity remains to be determined.

Comparison between Tibetan and Small-tailed Han sheep in adipocyte phenotype, lipid metabolism and energy homoeostasis regulation of adipose tissues when consuming diets of different energy levels

2020 ◽  
Vol 124 (7) ◽  
pp. 668-680
Author(s):  
Xiaoping Jing ◽  
Jianwei Zhou ◽  
Allan Degen ◽  
Wenji Wang ◽  
Yamin Guo ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Energy Balance ◽  
Mrna Expression ◽  
Fatty Acid Uptake ◽  
Negative Energy ◽  
Low Energy ◽  
Harsh Environment ◽  
Acid Uptake ◽  
Tibetan Sheep

AbstractThis study aimed to gain insight into how adipose tissue of Tibetan sheep regulates energy homoeostasis to cope with low energy intake under the harsh environment of the Qinghai-Tibetan Plateau (QTP). We compared Tibetan and Small-tailed Han sheep (n 24 of each breed), all wethers and 1·5 years of age, which were each divided randomly into four groups and offered diets of different digestible energy (DE) densities: 8·21, 9·33, 10·45 and 11·57 MJ DE/kg DM. When the sheep lost body mass and were assumed to be in negative energy balance: (1) adipocyte diameter in subcutaneous adipose tissue was smaller and decreased to a greater extent in Tibetan than in Small-tailed Han sheep, but the opposite occurred in the visceral adipose tissue; (2) Tibetan sheep showed higher insulin receptor mRNA expression and lower concentrations of catabolic hormones than Small-tailed Han sheep and (3) Tibetan sheep had lower capacity for glucose and fatty acid uptake than Small-tailed Han sheep. Moreover, Tibetan sheep had lower AMPKα mRNA expression but higher mammalian target of rapamycin mRNA expression in the adipocytes than Small-tailed Han sheep. We concluded that Tibetan sheep had lower catabolism but higher anabolism in adipose tissue and reduced the capacity for glucose and fatty acid uptake to a greater extent than Small-tailed Han sheep to maintain energy homoeostasis when in negative energy balance. These responses provide Tibetan sheep with a high ability to cope with low energy intake and with the harsh environment of the QTP.

scholarly journals Basal and cold-induced fatty acid uptake of human brown adipose tissue is impaired in obesity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
T. J. Saari ◽  
J. Raiko ◽  
M. U-Din ◽  
T. Niemi ◽  
M. Taittonen ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Brown Adipose

scholarly journals Ovarian Cycle-Specific Regulation of Adipose Tissue Lipid Storage by Testosterone in Female Nonhuman Primates

Endocrinology ◽  
2013 ◽  
Vol 154 (11) ◽  
pp. 4126-4135 ◽  
Author(s):  
Oleg Varlamov ◽  
Michael P. Chu ◽  
Whitney K. McGee ◽  
Judy L. Cameron ◽  
Robert W. O'Rourke ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Sex Hormones ◽  
Luteal Phase ◽  
Fatty Acid Uptake ◽  
Ovarian Cycle ◽  
Lipid Storage ◽  
Hormone Sensitive Lipase ◽  
Acid Uptake ◽  
Hormone Sensitive

Previous studies in rodents and humans suggest that hyperandrogenemia causes white adipose tissue (WAT) dysfunction in females, although the underlying mechanisms are poorly understood. In light of the differences in the length of the ovarian cycle between humans and rodents, we used a nonhuman primate model to elucidate the effects of chronic hyperandrogenemia on WAT function in vivo. Female rhesus macaques implanted with testosterone capsules developed insulin resistance and altered leptin secretion on a high-fat, Western-style diet. In control visceral WAT, lipolysis and hormone-sensitive lipase expression were upregulated during the luteal phase compared with the early follicular (menses) phase of the ovarian cycle. Hyperandrogenemia attenuated elevated lipolysis and hormone-sensitive lipase activity in visceral WAT during the luteal phase but not during menses. Under control conditions, insulin-stimulated Akt and Erk activation and fatty acid uptake in WAT were not significantly affected by the ovarian cycle. In contrast, testosterone treatment preferentially increased fatty acid uptake and insulin signaling at menses. The fatty acid synthase and glucose transporter-4 genes were upregulated by testosterone during the luteal phase. In summary, this study reveals ovarian stage-specific fluctuations in adipocyte lipolysis and suggests that male sex hormones increase and female sex hormones decrease lipid storage in female WAT.

Enhanced fatty acid uptake in visceral adipose tissue is not reversed by weight loss in obese individuals with the metabolic syndrome

Diabetologia ◽  
2014 ◽  
Vol 58 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Marco Bucci ◽  
Anna C. Karmi ◽  
Patricia Iozzo ◽  
Barbara A. Fielding ◽  
Antti Viljanen ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Weight Loss ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Visceral Adipose Tissue ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
The Metabolic Syndrome ◽  
Visceral Adipose

scholarly journals Thrombospondin-1 regulates adiposity and metabolic dysfunction in diet-induced obesity enhancing adipose inflammation and stimulating adipocyte proliferation

2013 ◽  
Vol 305 (3) ◽  
pp. E439-E450 ◽  
Author(s):  
Ping Kong ◽  
Carlos Gonzalez-Quesada ◽  
Na Li ◽  
Michele Cavalera ◽  
Dong-Wook Lee ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Weight Gain ◽  
Fatty Acid Uptake ◽  
Cytokine Signaling ◽  
Vascular Density ◽  
Acid Uptake ◽  
Metabolic Dysfunction ◽  
Diet Induced Obesity ◽  
Obesity And Diabetes

As a typical matricellular protein, thrombospondin (TSP)-1, binds to the structural matrix and regulates cellular behavior by modulating growth factor and cytokine signaling. Obesity and diabetes are associated with marked upregulation of TSP-1 in adipose tissue. We hypothesized that endogenous TSP-1 may play an important role in the pathogenesis of diet-induced obesity and metabolic dysfunction. Accordingly, we examined the effects of TSP-1 gene disruption on weight gain, adiposity, and adipose tissue inflammation in mice receiving a high-fat diet (HFD: 60% fat, 20% carbohydrate) or a high-carbohydrate low-fat diet (HCLFD: 10% fat, 70% carbohydrate). HFD mice had significantly higher TSP-1 expression in perigonadal adipose tissue; TSP-1 was predominantly localized in the adipose interstitium. TSP-1 loss attenuated weight gain and fat accumulation in HFD and HCLFD groups. Compared with corresponding wild-type animals, TSP-1-null mice had decreased insulin levels but exhibited elevated free fatty acid and triglyceride levels, suggesting impaired fatty acid uptake. TSP-1 loss did not affect adipocyte size and had no effect on adipose vascular density. However, TSP-1-null mice exhibited attenuated tumor necrosis factor-α mRNA expression and reduced macrophage infiltration, suggesting a role for TSP-1 in mediating obesity-associated inflammation. In vitro, TSP-1 enhanced proliferation of 3T3-L1 preadipocytes but did not modulate inflammatory cytokine and chemokine synthesis. In conclusion, TSP-1 upregulation contributes to weight gain, adipose growth, and the pathogenesis of metabolic dysfunction. The effects of TSP-1 may involve stimulation of adipocyte proliferation, activation of inflammatory signaling, and facilitated fatty acid uptake by adipocytes.

scholarly journals Lipid metabolism in women

2004 ◽  
Vol 63 (1) ◽  
pp. 153-160 ◽  
Author(s):  
Christine M. Williams
Keyword(s):  
Adipose Tissue ◽  
Cardiovascular Risk ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Body Fat ◽  
Adrenergic Receptors ◽  
Subcutaneous Fat ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Fat Depots

Differences in whole-body lipid metabolism between men and women are indicated by lower-body fat accumulation in women but more marked accumulation of fat in the intra-abdominal visceral fat depots of men. Circulating blood lipid concentrations also show gender-related differences. These differences are most marked in premenopausal women, in whom total cholesterol, LDL-cholesterol and triacylglycerol concentrations are lower and HDL-cholesterol concentration is higher than in men. Tendency to accumulate body fat in intra-abdominal fat stores is linked to increased risk of CVD, metabolic syndrome, diabetes and other insulin-resistant states. Differential regional regulation of adipose tissue lipolysis and lipogenesis must underlie gender-related differences in the tendency to accumulate fat in specific fat depots. However, empirical data to support current hypotheses remain limited at the present time because of the demanding and specialist nature of the methods used to study adipose tissue metabolism in human subjects. In vitro and in vivo data show greater lipolytic sensitivity of abdominal subcutaneous fat and lesser lipolytic sensitivity of femoral and gluteal subcutaneous fat in women than in men. These differences appear to be due to fewer inhibitory α adrenergic receptors in abdominal regions and greater α adrenergic receptors in gluteal and femoral regions in women than in men. There do not appear to be major gender-related differences in rates of fatty acid uptake (lipogenesis) in different subcutaneous adipose tissue regions. In visceral fat rates of both lipolysis and lipogenesis appear to be greater in men than in women; higher rates of lipolysis may be due to fewer α adrenergic receptors in this fat depot in men. Fatty acid uptake into this depot in the postprandial period is approximately 7-fold higher in men than in women. Triacylglycerol concentrations appear to be a stronger cardiovascular risk factor in women than in men, with particular implications for cardiovascular risk in diabetic women. The increased triacylglycerol concentrations observed in women taking hormone-replacement therapy (HRT) may explain the paradoxical findings of increased rates of CVD in women taking HRT that have been reported from recent primary and secondary prevention trials of HRT.

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