scholarly journals Impaired thermogenesis and sharp increases in plasma triglyceride levels in GPIHBP1-deficient mice during cold exposure

2018 ◽  
Vol 59 (4) ◽  
pp. 706-713 ◽  
Author(s):  
Mikael Larsson ◽  
Christopher M. Allan ◽  
Patrick J. Heizer ◽  
Yiping Tu ◽  
Norma P. Sandoval ◽  
...  
Keyword(s):  
Cold Exposure ◽  
Metabolic Stress ◽  
Density Lipoprotein ◽  
Plasma Triglyceride ◽  
Cell Protein ◽  
Cold Intolerance ◽  
Peripheral Tissues ◽  
Brown Adipose ◽  
Fatty Acid Release ◽  
Lipoprotein Binding

Glycosylphosphatidylinositol-anchored high density lipoprotein–binding protein 1 (GPIHBP1), an endothelial cell protein, binds LPL in the subendothelial spaces and transports it to the capillary lumen. In Gpihbp1−/− mice, LPL remains stranded in the subendothelial spaces, causing hypertriglyceridemia, but how Gpihbp1−/− mice respond to metabolic stress (e.g., cold exposure) has never been studied. In wild-type mice, cold exposure increases LPL-mediated processing of triglyceride-rich lipoproteins (TRLs) in brown adipose tissue (BAT), providing fuel for thermogenesis and leading to lower plasma triglyceride levels. We suspected that defective TRL processing in Gpihbp1−/− mice might impair thermogenesis and blunt the fall in plasma triglyceride levels. Indeed, Gpihbp1−/− mice exhibited cold intolerance, but the effects on plasma triglyceride levels were paradoxical. Rather than falling, the plasma triglyceride levels increased sharply (from ∼4,000 to ∼15,000 mg/dl), likely because fatty acid release by peripheral tissues drives hepatic production of TRLs that cannot be processed. We predicted that the sharp increase in plasma triglyceride levels would not occur in Gpihbp1−/−Angptl4−/− mice, where LPL activity is higher and baseline plasma triglyceride levels are lower. Indeed, the plasma triglyceride levels in Gpihbp1−/−Angptl4−/− mice fell during cold exposure. Metabolic studies revealed increased levels of TRL processing in the BAT of Gpihbp1−/−Angptl4−/− mice.

Diminished sympathetic nervous system activity in genetically obese (ob/ob) mouse

1983 ◽  
Vol 245 (2) ◽  
pp. E148-E154 ◽  
Author(s):  
J. B. Young ◽  
L. Landsberg
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Cold Exposure ◽  
Feedback Regulation ◽  
Turnover Rates ◽  
Interscapular Brown Adipose Tissue ◽  
Peripheral Tissues ◽  
Brown Adipose ◽  
Sympathetic Nervous ◽  
Long Acting

The genetically obese (ob/ob) mouse exhibits defective thermoregulatory responses to cold exposure. Pathophysiological explanations for this phenomenon have focused on abnormalities in intracellular metabolism or insensitivity of peripheral tissues to the thermogenic effects of catecholamines. Because the sympathetic nervous system (SNS) is subject to feedback regulation, a peripheral impairment in thermogenesis should be associated with a compensatory increase in SNS activity. To examine SNS activity in the ob/ob mouse, norepinephrine (NE) turnover was measured in heart and interscapular brown adipose tissue (IBAT) of ob/ob and lean mice. The results from studies utilizing radiolabeled NE or inhibition of NE biosynthesis with alpha-methyl-p-tyrosine to measure NE turnover demonstrated reductions in SNS activity of 33-56% in heart and of 45-73% in IBAT in ob/ob mice at ambient temperature (22 degrees C) compared with measurements in lean controls. During cold exposure (4 degrees C) NE turnover increased in heart and IBAT to a similar extent in both ob/ob and lean mice, but NE turnover rates in heart, and probably in IBAT as well, remained lower in the obese mice than in the lean despite the gradual development of hypothermia in the ob/ob mice during this period. Administration of naltrexone, a long-acting opiate antagonist, failed to reverse the suppression of SNS activity observed in the ob/ob mice. These data indicate that diminished SNS activity in ob/ob mice may be an additional factor contributing to the defective thermogenesis characteristic of these animals.

Cold exposure potentiates the effect of insulin on in vivo glucose uptake

1987 ◽  
Vol 253 (2) ◽  
pp. E179-E186 ◽  
Author(s):  
A. L. Vallerand ◽  
F. Perusse ◽  
L. J. Bukowiecki
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Glucose Uptake ◽  
White Adipose Tissue ◽  
Cold Exposure ◽  
Skeletal Muscles ◽  
Insulin Injection ◽  
Peripheral Tissues ◽  
Brown Adipose ◽  
Insulin Responses

The effects of cold exposure (48 h at 4 degrees C) and insulin injection (0.5 U/kg iv) on the rates of net 2-[3H]deoxyglucose uptake (Ki) in peripheral tissues were investigated in warm-acclimated rats (25 degrees C). Cold exposure and insulin treatment independently increased Ki values in skeletal muscles (soleus, extensor digitorum longus, and vastus lateralis), heart, white adipose tissue (subcutaneous, gonadal, and retroperitoneal), and brown adipose tissue (P less than 0.01). The effects of cold exposure were particularly evident in brown adipose tissue where the Ki increased greater than 100 times. When the two treatments were combined (insulin injection in cold-exposed rats), it was found that cold exposure synergistically enhanced the maximal insulin responses for glucose uptake in brown adipose tissue, all white adipose tissue depots, and skeletal muscles investigated. The results indicate that cold exposure induces an "insulin-like" effect on Ki that does not appear to be specifically associated with shivering thermogenesis in skeletal muscles, because that effect was observed in all insulin-sensitive tissues. The data also demonstrate that cold exposure significantly potentiates the maximal insulin responses for glucose uptake in the same tissues. This potentialization may result from an enhanced responsiveness of peripheral tissues to insulin, possibly occurring at metabolic steps lying beyond the insulin receptor and an increased tissue blood flow augmenting glucose and insulin availability and thereby amplifying glucose uptake.

Serotonin effect on deiodinating activity in the rat

2003 ◽  
Vol 81 (7) ◽  
pp. 747-751 ◽  
Author(s):  
Alessio Sullo ◽  
Guglielmo Brizzi ◽  
Nicola Maffulli
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Heat Production ◽  
Cold Exposure ◽  
Type Ii ◽  
Indirect Measure ◽  
Peripheral Tissues ◽  
Brown Adipose ◽  
The Brain

Serotonin (5-HT) and thyroid hormones are part of a complex system modulating eating behaviour and energy expenditure. 5'-Deiodinase (5'-D) converts the relatively inactive thyroxine (T4) to triiodothyronine (T3), and its activity is an indirect measure of T3 production in peripheral tissues, particularly in the brain, intrascapular brown adipose tissue (IBAT), heart, liver, and kidney. We evaluated the effect of 5-HT on 5'-D activity during basal conditions and after short (30 min) cold exposure (thyroid stimulating hormone stimulation test, TST). 5'-D activity was assessed in the liver, heart, brain, kidney, and IBAT. TST increases 5'-D activity in the brain, heart, and IBAT and decreases it in kidney, leaving it unchanged in the liver. 5-HT alone did not modify 5'-D activity in the organs under study but decreased it in the IBAT, heart, and brain when injected before the TST was administered. Our results confirm the important role of 5-HT in thermoregulation, given its peripheral site of action, in modulating heat production controlling intracellular T3 production. These effects are more evident when heat production is upregulated during cold exposure in organs containing type II 5'-D, such as the brain, heart, and IBAT, which are able to modify their function during conditions that alter energy balance. In conclusion, 5-HT may also act peripherally directly on the thyroid and organs containing type II 5'-D, thus controlling energy expenditure through heat production.Key words: serotonin, deiodinase activity, thyroid hormone, brown adipose tissue, thermogenesis, rat organs.

Cold exposure reverses inhibitory effects of fasting on peripheral glucose uptake in rats

1989 ◽  
Vol 257 (1) ◽  
pp. R96-R101 ◽  
Author(s):  
H. Shibata ◽  
F. Perusse ◽  
A. Vallerand ◽  
L. J. Bukowiecki
Keyword(s):  
Glucose Uptake ◽  
Cold Exposure ◽  
Plasma Glucose ◽  
Skeletal Muscles ◽  
Inhibitory Effects ◽  
Peripheral Tissues ◽  
Glucose Levels ◽  
Brown Adipose ◽  
Order Of Magnitude ◽  
Fasted Rats

The effects of fasting and cold exposure on glucose uptake in skeletal muscles (tibialis anterior, quadriceps, and soleus), heart, and brown adipose tissue (BAT) were studied in conscious rats. Glucose uptake was estimated by determining the glucose metabolic index of individual tissues using the 2-[3H]deoxyglucose method. Fasting for 18 h at 25 degrees C decreased plasma glucose levels (-40%) and glucose uptake in heart (-95%) and skeletal muscles (-64-90%) but did not significantly affect glucose uptake in BAT. Fasting for 48 h did not further decrease these parameters. On the other hand, cold exposure (48 h at 5 degrees C) of fed animals did not alter plasma glucose levels but increased glucose uptake in heart (73%), skeletal muscles (126-326%), and particularly in BAT (95-fold). Remarkably, cold exposure stimulated glucose uptake in BAT and skeletal muscles of 18-h fasted rats by the same order of magnitude as in fed animals (percentagewise), thereby indicating that glucose represents an essential metabolite for shivering (muscles) and nonshivering (BAT) thermogeneses. In the heart of starved animals, the cold-induced increase in glucose uptake was even more important (8-fold) than in fed animals. Considering that cold exposure of fasted rats results in a severe insulinopenia, it is suggested that cold exposure stimulates glucose uptake in peripheral tissues primarily by enhancing glucose oxidation via insulin-independent pathways.

Energy balance and diabetes. The effects of cold exposure, exercise training, and diet composition on glucose tolerance and glucose metabolism in rat peripheral tissues

1989 ◽  
Vol 67 (4) ◽  
pp. 382-393 ◽  
Author(s):  
Ludwik Jan Bukowiecki
Keyword(s):  
Insulin Resistance ◽  
Glucose Metabolism ◽  
Energy Expenditure ◽  
Exercise Training ◽  
Glucose Tolerance ◽  
Glucose Uptake ◽  
Cold Exposure ◽  
High Fat ◽  
Peripheral Tissues ◽  
Brown Adipose

The effects of cold exposure, exercise training, and diet (high fat versus high carbohydrate) on glucose tolerance and glucose metabolism in rat peripheral tissues will be briefly reviewed. Stimulation of energy expenditure by cold exposure (4 °C) or exercise training generally leads to decreased plasma insulin levels and to an improvement in glucose tolerance, suggesting that insulin action on peripheral tissues is increased when energy expenditure is stimulated. On the contrary, feeding high-fat diets to sedentary rats living in the warm (25 °C) induces hyperinsulinemia and insulin resistance resulting in a marked deterioration of glucose tolerance. Nevertheless, cold exposure reverses the diabetogenic effects of high-fat feeding, demonstrating that nutrition-induced insulin resistance is amplified in sedentary animals living at temperatures close to thermoneutrality. Radioactive tracer studies of 2-deoxyglucose uptake in peripheral tissues revealed that cold exposure synergistically potentiates the effects of insulin on glucose uptake in skeletal muscles as well as in white and brown adipose tissues. However, more recent data showed that cold exposure improves glucose tolerance and stimulates glucose uptake in starved animals (ie., in the virtual absence of circulating insulin) nearly by the same order of magnitude as in fed animals. It is therefore concluded that cold exposure, and possibly also exercise, improve glucose tolerance and stimulate glucose uptake in peripheral tissues primarily by enhancing glucose oxidation via insulin-independent pathways, and secondarily by increasing the responsiveness of peripheral tissues to insulin.Key words: insulin, brown adipose tissue, skeletal muscle, 2-deoxyglucose, diabetes.

Stimulatory effects of cold exposure and cold acclimation on glucose uptake in rat peripheral tissues

1990 ◽  
Vol 259 (5) ◽  
pp. R1043-R1049 ◽  
Author(s):  
A. L. Vallerand ◽  
F. Perusse ◽  
L. J. Bukowiecki
Keyword(s):  
Adipose Tissue ◽  
Glucose Uptake ◽  
Cold Acclimation ◽  
Cold Exposure ◽  
Skeletal Muscles ◽  
Contractile Activity ◽  
Peripheral Tissues ◽  
Brown Adipose ◽  
Shivering Thermogenesis ◽  
Stimulation Of

The effects of cold exposure on the net rates of 2-[3H]deoxy-D-glucose uptake (Ki) in rat peripheral tissues were investigated comparatively in warm- and cold-acclimated animals to determine whether cold acclimation induces regulatory alterations in glucose metabolism. Acute exposure of warm-acclimated (25 degrees C) rats to cold (48 h at 5 degrees C) markedly increased the Ki values in red and white skeletal muscles (2-5 times), in the heart (8 times), in several white adipose tissue (WAT) depots (4-20 times), and in brown adipose tissue (BAT) (110 times). After cold acclimation (3 wk at 5 degrees C), the Ki values further increased in the heart (15 times) and WAT (up to 29 times) but decreased in BAT (36 times). Remarkably, glucose uptake was still increased in muscles of cold-exposed/cold-acclimated animals (that do not shiver), demonstrating that enhanced glucose uptake may occur in muscles in the absence of shivering thermogenesis (or contractile activity). When cold-acclimated rats were returned to the warm for 18 h, the Ki values of all tissues, except WAT, returned to control levels. Cold exposure synergistically potentiated the stimulation of tissue glucose uptake induced by a maximal effective dose of insulin (0.5 U/kg iv) in warm- as well as in cold-acclimated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Assessing the Role of the Glycosylphosphatidylinositol-anchored High Density Lipoprotein-binding Protein 1 (GPIHBP1) Three-finger Domain in Binding Lipoprotein Lipase

2011 ◽  
Vol 286 (22) ◽  
pp. 19735-19743 ◽  
Author(s):  
Anne P. Beigneux ◽  
Brandon S. J. Davies ◽  
Shelly Tat ◽  
Jenny Chen ◽  
Peter Gin ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Lipoprotein Lipase ◽  
Binding Protein ◽  
Density Lipoprotein ◽  
High Density ◽  
Cell Protein ◽  
Apical Surface ◽  
Amino Terminal ◽  
Acidic Domain ◽  
Lipoprotein Binding

Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) is an endothelial cell protein that transports lipoprotein lipase (LPL) from the subendothelial spaces to the capillary lumen. GPIHBP1 contains two main structural motifs, an amino-terminal acidic domain enriched in aspartates and glutamates and a lymphocyte antigen 6 (Ly6) motif containing 10 cysteines. All of the cysteines in the Ly6 domain are disulfide-bonded, causing the protein to assume a three-fingered structure. The acidic domain of GPIHBP1 is known to be important for LPL binding, but the involvement of the Ly6 domain in LPL binding requires further study. To assess the importance of the Ly6 domain, we created a series of GPIHBP1 mutants in which each residue of the Ly6 domain was changed to alanine. The mutant proteins were expressed in Chinese hamster ovary (CHO) cells, and their expression level on the cell surface and their ability to bind LPL were assessed with an immunofluorescence microscopy assay and a Western blot assay. We identified 12 amino acids within GPIHBP1, aside from the conserved cysteines, that are important for LPL binding; nine of those were clustered in finger 2 of the GPIHBP1 three-fingered motif. The defective GPIHBP1 proteins also lacked the ability to transport LPL from the basolateral to the apical surface of endothelial cells. Our studies demonstrate that the Ly6 domain of GPIHBP1 is important for the ability of GPIHBP1 to bind and transport LPL.

scholarly journals A novel NanoBiT-based assay monitors the interaction between lipoprotein lipase and GPIHBP1 in real time

2020 ◽  
Vol 61 (4) ◽  
pp. 546-559 ◽  
Author(s):  
Shwetha K. Shetty ◽  
Rosemary L. Walzem ◽  
Brandon S. J. Davies
Keyword(s):  
Fatty Acids ◽  
Endothelial Cells ◽  
Real Time ◽  
Density Lipoprotein ◽  
Vascular Wall ◽  
Poloxamer 407 ◽  
Cell Protein ◽  
Specificity And Sensitivity ◽  
Lipoprotein Binding ◽  
Hydrolysis Of

The hydrolysis of triglycerides in triglyceride-rich lipoproteins by LPL is critical for the delivery of triglyceride-derived fatty acids to tissues, including heart, skeletal muscle, and adipose tissues. Physiologically active LPL is normally bound to the endothelial cell protein glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1), which transports LPL across endothelial cells, anchors LPL to the vascular wall, and stabilizes LPL activity. Disruption of LPL-GPIHBP1 binding significantly alters triglyceride metabolism and lipid partitioning. In this study, we modified the NanoLuc® Binary Technology split-luciferase system to develop a novel assay that monitors the binding of LPL to GPIHBP1 on endothelial cells in real time. We validated the specificity and sensitivity of the assay using endothelial lipase and a mutant version of LPL and found that this assay reliably and specifically detected the interaction between LPL and GPIHBP1. We then interrogated various endogenous and exogenous inhibitors of LPL-mediated lipolysis for their ability to disrupt the binding of LPL to GPIHBP1. We found that angiopoietin-like (ANGPTL)4 and ANGPTL3-ANGPTL8 complexes disrupted the interactions of LPL and GPIHBP1, whereas the exogenous LPL blockers we tested (tyloxapol, poloxamer-407, and tetrahydrolipstatin) did not. We also found that chylomicrons could dissociate LPL from GPIHBP1 and found evidence that this dissociation was mediated in part by the fatty acids produced by lipolysis. These results demonstrate the ability of this assay to monitor LPL-GPIHBP1 binding and to probe how various agents influence this important complex.

Chronic norepinephrine infusion stimulates glucose uptake in white and brown adipose tissues

1994 ◽  
Vol 266 (3) ◽  
pp. R914-R920 ◽  
Author(s):  
X. Liu ◽  
F. Perusse ◽  
L. J. Bukowiecki
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Glucose Uptake ◽  
White Adipose Tissue ◽  
Cold Exposure ◽  
Skeletal Muscles ◽  
Interscapular Brown Adipose Tissue ◽  
Peripheral Tissues ◽  
Glucose Levels ◽  
Brown Adipose

Cold exposure activates the sympathetic nervous system and markedly stimulates glucose uptake in rat peripheral tissues [A. L. Vallerand, F. Perusse, and L. J. Bukowiecki. Am. J. Physiol 259 (Regulatory Integrative Comp. Physiol. 28): R1043-R1049, 1990]. To test whether norepinephrine (NE) mimics the effects of cold exposure, we estimated the effects of chronic NE treatment on tissue glucose uptake by determining the glucose metabolic index using the 2-[1,2-3H(N)]deoxy-D-glucose method. NE was administered in conscious rats at various doses (ranging from 1.9 to 25.1 nmol.kg-1.min-1) during 4 days via minipumps implanted subcutaneously. At doses > 10 nmol.kg-1.min-1, NE maximally stimulated glucose uptake in interscapular brown adipose tissue (approximately 50 times above controls) and epididymal white adipose tissue (approximately 3 times above controls). NE infusion (18.8 nmol.kg-1.min-1) increased the circulating levels of NE from 1.1 +/- 0.1 to 19.2 +/- 0.4 nM (P < 0.001), which is in the range of concentrations for the stimulatory effects of NE on glucose uptake in isolated brown adipocytes. At all concentrations tested, NE infusion did not stimulate glucose uptake in the heart and skeletal muscles. NE treatment did not significantly alter plasma insulin or glucose levels but increased the concentration of circulating free fatty acids. The capacity of brown adipose tissue for NE stimulation of glucose uptake (expressed per g of tissue) was much higher than that of white adipose tissue (100 times), various types of white or red skeletal muscles (10-80 times), or the heart (3-4 times).(ABSTRACT TRUNCATED AT 250 WORDS)

P53 regulates the lipid metabolism response to metabolic stress in brown adipose tissue

2020 ◽  
Author(s):  
G Lenihan-Geels ◽  
F Garcia-Carrizo ◽  
C Li ◽  
M Oster ◽  
A Prokesch ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Brown Adipose Tissue ◽  
Metabolic Stress ◽  
Brown Adipose
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