Exercise induces human lipoprotein lipase gene expression in skeletal muscle but not adipose tissue

1995 ◽  
Vol 268 (2) ◽  
pp. E229-E236 ◽  
Author(s):  
R. L. Seip ◽  
T. J. Angelopoulos ◽  
C. F. Semenkovich

Lipoprotein lipase (LPL) is regulated by exercise in humans, but the effects of exercise on LPL expression in different tissues and the molecular mechanisms involved are unclear. We assessed the effects of 5-13 consecutive days of supervised exercise on tissue LPL expression as well as fasting plasma lipids and lipoproteins in 32 sedentary, weight-stable adult men. In skeletal muscle, exercise training increased the mean LPL mRNA level by 117% (P = 0.037), LPL protein mass by 53% (P = 0.038), and total LPL enzyme activity by 35% (P = 0.025). In adipose tissue, mean LPL mRNA, protein mass, and activity did not change. Exercise decreased triglycerides [from 172 +/- 4.3 to 127 +/- 3.2 (SE) mg/dl, P = 0.002], total cholesterol (from 188 +/- 1.2 to 181 +/- 1.0 mg/dl, P = 0.011), and very low-density lipoprotein-cholesterol (from 30.1 +/- 0.9 to 22.0 +/- 0.8, P = 0.004) and increased high-density lipoprotein cholesterol (HDL-C; from 43.4 +/- 0.35 to 45.0 +/- 0.37, P = 0.030) and HDL2-C (from 6.6 +/- 0.21 to 7.7 +/- 0.19, P = 0.021). Changes in muscle but not adipose tissue heparin-releasable LPL activity were inversely correlated (r = -0.435, P < 0.034) with changes in triglycerides. These data suggest the existence of an exercise stimulus intrinsic to skeletal muscle, which raises LPL activity in part by pretranslational mechanisms, a process that contributes to the improvement in circulating lipids seen with physical activity.

Author(s):  
Kristian Kølby Kristensen ◽  
Katrine Zinck Leth-Espensen ◽  
Anni Kumari ◽  
Anne Louise Grønnemose ◽  
Anne-Marie Lund-Winther ◽  
...  

Intravascular processing of triglyceride-rich lipoproteins (TRLs) is crucial for delivery of dietary lipids fueling energy metabolism in heart and skeletal muscle and for storage in white adipose tissue. During the last decade, mechanisms underlying focal lipolytic processing of TRLs along the luminal surface of capillaries have been clarified by fresh insights into the functions of lipoprotein lipase (LPL); LPL’s dedicated transporter protein, glycosylphosphatidylinositol-anchored high density lipoprotein–binding protein 1 (GPIHBP1); and its endogenous inhibitors, angiopoietin-like (ANGPTL) proteins 3, 4, and 8. Key discoveries in LPL biology include solving the crystal structure of LPL, showing LPL is catalytically active as a monomer rather than as a homodimer, and that the borderline stability of LPL’s hydrolase domain is crucial for the regulation of LPL activity. Another key discovery was understanding how ANGPTL4 regulates LPL activity. The binding of ANGPTL4 to LPL sequences adjacent to the catalytic cavity triggers cooperative and sequential unfolding of LPL’s hydrolase domain resulting in irreversible collapse of the catalytic cavity and loss of LPL activity. Recent studies have highlighted the importance of the ANGPTL3–ANGPTL8 complex for endocrine regulation of LPL activity in oxidative organs (e.g., heart, skeletal muscle, brown adipose tissue), but the molecular mechanisms have not been fully defined. New insights have also been gained into LPL–GPIHBP1 interactions and how GPIHBP1 moves LPL to its site of action in the capillary lumen. GPIHBP1 is an atypical member of the LU (Ly6/uPAR) domain protein superfamily, containing an intrinsically disordered and highly acidic N-terminal extension and a disulfide bond–rich three-fingered LU domain. Both the disordered acidic domain and the folded LU domain are crucial for the stability and transport of LPL, and for modulating its susceptibility to ANGPTL4-mediated unfolding. This review focuses on recent advances in the biology and biochemistry of crucial proteins for intravascular lipolysis.


2000 ◽  
Vol 89 (2) ◽  
pp. 472-480 ◽  
Author(s):  
Peter W. Grandjean ◽  
Stephen F. Crouse ◽  
J. James Rohack

To compare postexercise changes in plasma lipids and lipoprotein enzymes in 13 hypercholesterolemic (HC) and 12 normocholesterolemic men [total cholesterol (TC) 252 ± 5 vs. 179 ± 5 mg/dl], fasting blood samples were obtained 24 h before, immediately, 24, and 48 h after a single bout of treadmill walking (70% peak O2consumption, 500 kcal expenditure). Significant findings ( P < 0.05 for all) for plasma volume-adjusted lipid and enzyme variables were that TC, low-density-lipoprotein cholesterol, and cholesterol ester transfer protein activity were higher in the HC group but did not influence the lipid responses to exercise. Across groups, TC was transiently reduced immediately after exercise but returned to baseline levels by 24 h postexercise. Decreases in triglyceride and increases in high-density-lipoprotein cholesterol (HDL-C) and HDL3-C were observed 24 h after exercise and lasted through 48 h. Lipoprotein lipase activity was elevated by 24 h and remained elevated 48 h after exercise. HDL2-C, cholesterol ester transfer protein activity, hepatic triglyceride lipase, and lecithin: cholesterol acyltransferase activities did not change after exercise. These data indicate that the exercise-induced changes in HDL-C and triglyceride are similar in HC and normocholesterolemic men and may be mediated, at least in part, by an increase in lipoprotein lipase activity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Qu ◽  
Sarah Fourman ◽  
Maureen Fitzgerald ◽  
Min Liu ◽  
Supna Nair ◽  
...  

AbstractApolipoprotein A4 (APOA4) is one of the most abundant and versatile apolipoproteins facilitating lipid transport and metabolism. APOA4 is synthesized in the small intestine, packaged onto chylomicrons, secreted into intestinal lymph and transported via circulation to several tissues, including adipose. Since its discovery nearly 4 decades ago, to date, only platelet integrin αIIbβ3 has been identified as APOA4 receptor in the plasma. Using co-immunoprecipitation coupled with mass spectrometry, we probed the APOA4 interactome in mouse gonadal fat tissue, where ApoA4 gene is not transcribed but APOA4 protein is abundant. We demonstrate that lipoprotein receptor-related protein 1 (LRP1) is the cognate receptor for APOA4 in adipose tissue. LRP1 colocalized with APOA4 in adipocytes; it interacted with APOA4 under fasting condition and their interaction was enhanced during lipid feeding concomitant with increased APOA4 levels in plasma. In 3T3-L1 mature adipocytes, APOA4 promoted glucose uptake both in absence and presence of insulin in a dose-dependent manner. Knockdown of LRP1 abrogated APOA4-induced glucose uptake as well as activation of phosphatidylinositol 3 kinase (PI3K)-mediated protein kinase B (AKT). Taken together, we identified LRP1 as a novel receptor for APOA4 in promoting glucose uptake. Considering both APOA4 and LRP1 are multifunctional players in lipid and glucose metabolism, our finding opens up a door to better understand the molecular mechanisms along APOA4-LRP1 axis, whose dysregulation leads to obesity, cardiovascular disease, and diabetes.


Author(s):  
Sihoon Park ◽  
Jae-Joon Lee ◽  
Hye-Won Shin ◽  
Sunyoon Jung ◽  
Jung-Heun Ha

Soybean koji refers to steamed soybeans inoculated with microbial species. Soybean fermentation improves the health benefits of soybeans. Obesity is a serious health concern owing to its increasing incidence rate and high association with other metabolic diseases. Therefore, we investigated the effects of soybean and soybean koji on high-fat diet-induced obesity in rats. Five-week-old male Sprague-Dawley rats were randomly divided into four groups (n = 8/group) as follows: (1) regular diet (RD), (2) high-fat diet (HFD), (3) HFD + steamed soybean (HFD+SS), and (4) HFD + soybean koji (HFD+SK). SK contained more free amino acids and unsaturated fatty acids than SS. In a rat model of obesity, SK consumption significantly alleviated the increase in weight of white adipose tissue and mRNA expression of lipogenic genes, whereas SS consumption did not. Both SS and SK reduced serum triglyceride, total cholesterol, and low-density lipoprotein cholesterol levels, and increased high-density lipoprotein cholesterol levels. SS and SK also inhibited lipid accumulation in the liver and white adipose tissue and reduced adipocyte size. Although both SS and SK could alleviate HFD-induced dyslipidemia, SK has better anti-obesity effects than SS by regulating lipogenesis. Overall, SK is an excellent functional food that may prevent obesity.


2008 ◽  
Vol 100 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Sarah Dutton ◽  
Paul Trayhurn

Angiopoietin-like protein 4 (Angptl4)/FIAF (fasting-induced adipose factor) was first identified as a target for PPAR and to be strongly induced in white adipose tissue (WAT) by fasting. Here we have examined the regulation of the expression and release of this adipokine in mouse WAT and in 3T3-L1 adipocytes. Angptl4/FIAF expression was measured by RT-PCR and real-time PCR; plasma Angptl4/FIAF and release of the protein in cell culture was determined by western blotting. The Angptl4/FIAF gene was expressed in each of the major WAT depots of mice, the mRNA level in WAT being similar to the liver and much higher (>50-fold) than skeletal muscle. Fasting mice (18 h) resulted in a substantial increase in Angptl4/FIAF mRNA in liver and muscle (9·5- and 21-fold, respectively); however, there was no effect of fasting on Angptl4/FIAF mRNA in WAT and the plasma level of Angptl4/FIAF was unchanged. The Angptl4/FIAF gene was expressed in 3T3-L1 adipocytes before and after differentiation, the level increasing post-differentiation; Angptl4/FIAF was released into the culture medium. Insulin, leptin, dexamethasone, noradrenaline, TNFα and several IL (IL-1β, IL-6, IL-10, IL-18) had little effect on Angptl4/FIAF mRNA levels in 3T3-L1 adipocytes. However, a major stimulation of Angptl4/FIAF expression was observed with rosiglitazone and the inflammatory prostaglandins PGD2 and PGJ2. Angptl4/FIAF does not act as an adipose tissue signal of nutritional status, but is markedly induced by fasting in liver and skeletal muscle.


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