Advertisement

Microsomal triglyceride transfer protein regulates intracellular lipolysis in adipocytes independent of its lipid transfer activity

Published:October 09, 2022DOI:https://doi.org/10.1016/j.metabol.2022.155331

      Highlights

      • Adipose specific MTP knockout mice gain less weight on an obesogenic diet.
      • Adipose specific MTP knockout mice adapt better to cold challenge.
      • Adipocyte MTP regulates basal lipolysis by inhibiting ATGL.
      • Lipid transfer activity of MTP is not essential to inhibit ATGL activity.
      • MTP inhibits ATGL activity by direct protein-protein interactions.

      Abstract

      Background

      The triglyceride (TG) transfer activity of microsomal triglyceride transfer protein (MTP) is essential for lipoprotein assembly in the liver and intestine; however, its function in adipose tissue, which does not assemble lipoproteins, is unknown. Here we have elucidated the function of MTP in adipocytes.

      Approach and results

      We demonstrated that MTP is present on lipid droplets in human adipocytes. Adipose-specific MTP deficient (A-Mttp−/−) male and female mice fed an obesogenic diet gained less weight than Mttpf/f mice, had less fat mass, smaller adipocytes and were insulin sensitive. A-Mttp−/− mice showed higher energy expenditure than Mttpf/f mice. During a cold challenge, A-Mttp−/− mice maintained higher body temperature by mobilizing more fatty acids. Biochemical studies indicated that MTP deficiency de-repressed adipose triglyceride lipase (ATGL) activity and increased TG lipolysis. Both wild type MTP and mutant MTP deficient in TG transfer activity interacted with and inhibited ATGL activity. Thus, the TG transfer activity of MTP is not required for ATGL inhibition. C-terminally truncated ATGL that retains its lipase activity interacted less efficiently than full-length ATGL.

      Conclusion

      Our findings demonstrate that adipose-specific MTP deficiency increases ATGL-mediated TG lipolysis and enhances energy expenditure, thereby resisting diet-induced obesity. We speculate that the regulatory function of MTP involving protein-protein interactions might have evolved before the acquisition of TG transfer activity in vertebrates. Adipose-specific inhibition of MTP-ATGL interactions may ameliorate obesity while avoiding the adverse effects associated with inhibition of the lipid transfer activity of MTP.

      Abbreviations:

      ApoB-Lps (apoB-containing lipoproteins), ATGL (adipose triglyceride lipase activity), ATGLi (ATGL inhibitor), CLAMS (comprehensive laboratory animal monitoring system), CGI-58 (comparative gene identification-58), DEXA (dual-energy X-ray absorptiometry), FFA (free fatty acid), HSL (hormone sensitive lipase), HSLi (HSL inhibitor), LD (lipid droplet), MTP (microsomal triglyceride transfer protein), NBD (nitrobenzoxadiazole), OCR (oxygen consumption rate), RER (respiratory exchange ratio), SVF (stromal vascular fraction), TG (triglyceride)

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Metabolism - Clinical and Experimental
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Hussain M.M.
        • Shi J.
        • Dreizen P.
        Microsomal triglyceride transfer protein and its role in apolipoprotein B-lipoprotein assembly.
        J Lipid Res. 2003; 44: 22-32
        • Wetterau J.R.
        • Aggerbeck L.P.
        • Bouma M.E.
        • Eisenberg C.
        • Munck A.
        • Hermier M.
        • et al.
        Absence of microsomal triglyceride transfer protein in individuals with abetalipoproteinemia.
        Science. 1992; 258: 999-1001
        • Rader D.J.
        • Kastelein J.J.
        Lomitapide and mipomersen: two first-in-class drugs for reducing low-density lipoprotein cholesterol in patients with homozygous familial hypercholesterolemia.
        Circulation. 2014; 129: 1022-1032
        • Berberich A.J.
        • Hegele R.A.
        Lomitapide for the treatment of hypercholesterolemia.
        Expert Opin Pharmacother. 2017; 18: 1261-1268
        • Cuchel M.
        • Bloedon L.T.
        • Szapary P.O.
        • Kolansky D.M.
        • Wolfe M.L.
        • Sarkis A.
        • et al.
        Inhibition of microsomal triglyceride transfer protein in familial hypercholesterolemia.
        N Engl J Med. 2007; 356: 148-156
        • Iqbal J.
        • Walsh M.T.
        • Hammad S.M.
        • Cuchel M.
        • Tarugi P.
        • Hegele R.A.
        • et al.
        Microsomal triglycerdie transfer protein transfers and determines plasma concentrations of ceramide and sphingomyelin but not glycosylceramide.
        J Biol Chem. 2015; 290: 25863-25875
        • Brozovic S.
        • Nagaishi T.
        • Yoshida M.
        • Betz S.
        • Salas A.
        • Chen D.H.
        • et al.
        CD1d function is regulated by microsomal triglyceride transfer protein.
        Nat Med. 2004; 10: 535-539
        • Bradbury P.
        • Mann C.J.
        • Kochl S.
        • Anderson T.A.
        • Chester S.A.
        • Hancock J.M.
        • et al.
        A common binding site on the microsomal triglyceride transfer protein for apolipoprotein B and protein disulfide isomerase.
        J Biol Chem. 1999; 274: 3159-3164
        • Bakillah A.
        • Hussain M.M.
        Binding of microsomal triglyceride transfer protein to lipid vesicles results in increased affinity for apolipoprotein B: identification of novel, intracellular MTP/lipid complexes.
        Circulation. 1999; 100: 3934
        • Hussain M.M.
        • Bakillah A.
        • Nayak N.
        • Shelness G.S.
        Amino acids 430–570 in apolipoprotein B are critical for its binding to microsomal triglyceride transfer protein.
        J Biol Chem. 1998; 273: 25612-25615
        • Dougan S.K.
        • Rava P.
        • Hussain M.M.
        • Blumberg R.S.
        MTP regulated by an alternate promoter is essential for NKT cell development.
        J. Exp. Med. 2007; 204: 533-545
        • Dougan S.K.
        • Salas A.
        • Rava P.
        • Agyemang A.
        • Kaser A.
        • Morrison J.
        • et al.
        Microsomal triglyceride transfer protein lipidation and control of CD1d on antigen-presenting cells.
        J Exp Med. 2005; 202: 529-539
        • Swift L.L.
        • Kakkad B.
        • Boone C.
        • Jovanovska A.
        • Jerome W.G.
        • Mohler P.J.
        • et al.
        Microsomal triglyceride transfer protein expression in adipocytes: a new component in fat metabolism.
        FEBS Lett. 2005; 579: 3183-3189
        • Love J.D.
        • Suzuki T.
        • Robinson D.B.
        • Harris C.M.
        • Johnson J.E.
        • Mohler P.J.
        • et al.
        Microsomal triglyceride transfer protein (MTP) associates with cytosolic lipid droplets in 3T3-L1 adipocytes.
        PLoS One. 2015; 10e0135598
        • Bakillah A.
        • Hussain M.M.
        Mice subjected to aP2-cre mediated ablation of microsomal triglyceride transfer protein are resistant to high fat diet induced obesity.
        Nutr Metab (Lond). 2016; 13: 1
        • Swift L.L.
        • Love J.D.
        • Harris C.M.
        • Chang B.H.
        • Jerome W.G.
        Microsomal triglyceride transfer protein contributes to lipid droplet maturation in adipocytes.
        PLoS One. 2017; 12e0181046
        • Rajan S.
        • Satish S.
        • Shankar K.
        • Pandeti S.
        • Varshney S.
        • Srivastava A.
        • et al.
        Aegeline inspired synthesis of novel beta3-AR agonist improves insulin sensitivity in vitro and in vivo models of insulin resistance.
        Metabolism. 2018; 85: 1-13
        • Rajan S.
        • Shankar K.
        • Beg M.
        • Varshney S.
        • Gupta A.
        • Srivastava A.
        • et al.
        Chronic hyperinsulinemia reduces insulin sensitivity and metabolic functions of brown adipocyte.
        J Endocrinol. 2016; 230: 275-290
        • Lass A.
        • Zimmermann R.
        • Haemmerle G.
        • Riederer M.
        • Schoiswohl G.
        • Schweiger M.
        • et al.
        Adipose triglyceride lipase-mediated lipolysis of cellular fat stores is activated by CGI-58 and defective in chanarin-dorfman syndrome.
        Cell Metab. 2006; 3: 309-319
        • Rajan S.
        • de Guzman H.C.
        • Palaia T.
        • Goldberg I.J.
        • Hussain M.M.
        A simple, rapid, and sensitive fluorescence-based method to assess triacylglycerol hydrolase activity.
        J Lipid Res. 2021; 62100115
        • Schweiger M.
        • Eichmann T.O.
        • Taschler U.
        • Zimmermann R.
        • Zechner R.
        • Lass A.
        Measurement of lipolysis.
        Methods Enzymol. 2014; 538: 171-193
        • Rajan S.
        • Panzade G.
        • Srivastava A.
        • Shankar K.
        • Pandey R.
        • Kumar D.
        • et al.
        miR-876-3p regulates glucose homeostasis and insulin sensitivity by targeting adiponectin.
        J Endocrinol. 2018; 239: 1-17
        • Gupta A.
        • Singh V.K.
        • Kumar D.
        • Yadav P.
        • Kumar S.
        • Beg M.
        • et al.
        Curcumin-3,4-dichloro phenyl pyrazole (CDPP) overcomes curcumin's low bioavailability, inhibits adipogenesis and ameliorates dyslipidemia by activating reverse cholesterol transport.
        Metabolism. 2017; 73: 109-124
        • Grabner G.F.
        • Guttenberger N.
        • Mayer N.
        • Migglautsch-Sulzer A.K.
        • Lembacher-Fadum C.
        • Fawzy N.
        • et al.
        Small-molecule inhibitors targeting lipolysis in human adipocytes.
        J Am Chem Soc. 2022; 144: 6237-6250
        • Athar H.
        • Iqbal J.
        • Jiang X.C.
        • Hussain M.M.
        A simple, rapid, and sensitive fluorescence assay for microsomal triglyceride transfer protein.
        J Lipid Res. 2004; 45: 764-772
        • Rava P.
        • Athar H.
        • Johnson C.
        • Hussain M.M.
        Transfer of cholesteryl esters and phospholipids as well as net deposition by microsomal triglyceride transfer protein.
        J Lipid Res. 2005; 46: 1779-1785
        • Fischer A.W.
        • Cannon B.
        • Nedergaard J.
        Optimal housing temperatures for mice to mimic the thermal environment of humans: an experimental study.
        Mol Metab. 2018; 7: 161-170
        • Reitman M.L.
        Of mice and men - environmental temperature, body temperature, and treatment of obesity.
        FEBS Lett. 2018; 592: 2098-2107
        • Shin H.
        • Ma Y.
        • Chanturiya T.
        • Cao Q.
        • Wang Y.
        • Kadegowda A.K.G.
        • et al.
        Lipolysis in Brown adipocytes is not essential for cold-induced thermogenesis in mice.
        Cell Metab. 2017; 26e5
        • Schreiber R.
        • Diwoky C.
        • Schoiswohl G.
        • Feiler U.
        • Wongsiriroj N.
        • Abdellatif M.
        • et al.
        Cold-induced thermogenesis depends on ATGL-mediated lipolysis in cardiac muscle, but not Brown adipose tissue.
        Cell Metab. 2017; 26e7
        • Preite N.Z.
        • Nascimento B.P.
        • Muller C.R.
        • Americo A.L.
        • Higa T.S.
        • Evangelista F.S.
        • et al.
        Disruption of beta3 adrenergic receptor increases susceptibility to DIO in mouse.
        J Endocrinol. 2016; 231: 259-269
        • Fan H.
        • Zhang Y.
        • Zhang J.
        • Yao Q.
        • Song Y.
        • Shen Q.
        • et al.
        Cold-inducible Klf9 regulates thermogenesis of Brown and Beige fat.
        Diabetes. 2020; 69: 2603-2618
        • Rosen E.D.
        • Spiegelman B.M.
        Adipocytes as regulators of energy balance and glucose homeostasis.
        Nature. 2006; 444: 847-853
        • Zimmermann R.
        • Strauss J.G.
        • Haemmerle G.
        • Schoiswohl G.
        • Birner-Gruenberger R.
        • Riederer M.
        • et al.
        Fat mobilization in adipose tissue is promoted by adipose triglyceride lipase.
        Science. 2004; 306: 1383-1386
        • Zechner R.
        • Zimmermann R.
        • Eichmann T.O.
        • Kohlwein S.D.
        • Haemmerle G.
        • Lass A.
        • et al.
        FAT SIGNALS - lipases and lipolysis in lipid metabolism and signaling.
        Cell Metab. 2012; 15: 279-291
        • Zechner R.
        FAT FLUX: enzymes, regulators, and pathophysiology of intracellular lipolysis.
        EMBO Mol Med. 2015; 7: 359-362
        • Recazens E.
        • Mouisel E.
        • Langin D.
        Hormone-sensitive lipase: sixty years later.
        Prog Lipid Res. 2021; 82101084
        • Grabner G.F.
        • Xie H.
        • Schweiger M.
        • Zechner R.
        Lipolysis: cellular mechanisms for lipid mobilization from fat stores.
        Nat Metab. 2021; 3: 1445-1465
        • Schoiswohl G.
        • Stefanovic-Racic M.
        • Menke M.N.
        • Wills R.C.
        • Surlow B.A.
        • Basantani M.K.
        • et al.
        Impact of reduced ATGL-mediated adipocyte lipolysis on obesity-associated insulin resistance and inflammation in male mice.
        Endocrinology. 2015; 156: 3610-3624
        • Khatun I.
        • Walsh M.T.
        • Hussain M.M.
        Loss of both phospholipid and triglyceride transfer activities of microsomal triglyceride transfer protein in abetalipoproteinemia.
        J Lipid Res. 2013; 54: 1541-1549
        • Walsh M.T.
        • Iqbal J.
        • Josekutty J.
        • Soh J.
        • Di Leo E.
        • Ozaydin E.
        • et al.
        Novel abetalipoproteinemia missense mutation highlights the importance of the N-terminal beta-barrel in microsomal triglyceride transfer protein function.
        Circ Cardiovasc Genet. 2015; 8: 677-687
        • Read J.
        • Anderson T.A.
        • Ritchie P.J.
        • Vanloo B.
        • Amey J.
        • Levitt D.
        • et al.
        A mechanism of membrane neutral lipid acquisition by the microsomal triglyceride transfer protein.
        J Biol Chem. 2000; 275: 30372-30377
        • Gruber A.
        • Cornaciu I.
        • Lass A.
        • Schweiger M.
        • Poeschl M.
        • Eder C.
        • et al.
        The N-terminal region of comparative gene identification-58 (CGI-58) is important for lipid droplet binding and activation of adipose triglyceride lipase.
        J Biol Chem. 2010; 285: 12289-12298
        • Bakillah A.
        • Hussain M.M.
        Binding of microsomal triglyceride transfer protein to lipids results in increased affinity for apolipoprotein B: evidence for stable microsomal MTP-lipid complexes.
        J Biol Chem. 2001; 276: 31466-31473
        • Hofer P.
        • Boeszoermenyi A.
        • Jaeger D.
        • Feiler U.
        • Arthanari H.
        • Mayer N.
        • et al.
        Fatty acid-binding proteins interact with comparative gene Identification-58 linking lipolysis with lipid ligand shuttling.
        J Biol Chem. 2015; 290: 18438-18453
        • Schweiger M.
        • Schoiswohl G.
        • Lass A.
        • Radner F.P.
        • Haemmerle G.
        • Malli R.
        • et al.
        The C-terminal region of human adipose triglyceride lipase affects enzyme activity and lipid droplet binding.
        J Biol Chem. 2008; 283: 17211-17220
        • Cornaciu I.
        • Boeszoermenyi A.
        • Lindermuth H.
        • Nagy H.M.
        • Cerk I.K.
        • Ebner C.
        • et al.
        The minimal domain of adipose triglyceride lipase (ATGL) ranges until leucine 254 and can be activated and inhibited by CGI-58 and G0S2, respectively.
        PLoS One. 2011; 6e26349
        • Kulminskaya N.
        • Radler C.
        • Viertlmayr R.
        • Heier C.
        • Hofer P.
        • Colaco-Gaspar M.
        • et al.
        Optimized expression and purification of adipose triglyceride lipase improved hydrolytic and transacylation activities in vitro.
        J Biol Chem. 2021; 297101206
        • Zeissig S.
        • Dougan S.K.
        • Barral D.C.
        • Junker Y.
        • Chen Z.G.
        • Kaser A.
        • et al.
        Primary deficiency of microsomal triglyceride transfer protein in human abetalipoproteinemia is associated with loss of CD1 function.
        J Clin Investig. 2010; 120: 2889-2899
        • Haemmerle G.
        • Lass A.
        • Zimmermann R.
        • Gorkiewicz G.
        • Meyer C.
        • Rozman J.
        • et al.
        Defective lipolysis and altered energy metabolism in mice lacking adipose triglyceride lipase.
        Science. 2006; 312: 734-737
        • Trites M.J.
        • Clugston R.D.
        The role of adipose triglyceride lipase in lipid and glucose homeostasis: lessons from transgenic mice.
        Lipids Health Dis. 2019; 18: 204
        • Ahmadian M.
        • Duncan R.E.
        • Varady K.A.
        • Frasson D.
        • Hellerstein M.K.
        • Birkenfeld A.L.
        • et al.
        Adipose overexpression of desnutrin promotes fatty acid use and attenuates diet-induced obesity.
        Diabetes. 2009; 58: 855-866
        • Hofer P.
        • Taschler U.
        • Schreiber R.
        • Kotzbeck P.
        • Schoiswohl G.
        The lipolysome-a highly complex and dynamic protein network orchestrating cytoplasmic triacylglycerol degradation.
        Metabolites. 2020; 10
        • Kulminskaya N.
        • Oberer M.
        Protein-protein interactions regulate the activity of adipose triglyceride lipase in intracellular lipolysis.
        Biochimie. 2020; 169: 62-68
        • Lundquist P.K.
        • Shivaiah K.K.
        • Espinoza-Corral R.
        Lipid droplets throughout the evolutionary tree.
        Prog Lipid Res. 2020; 78101029
        • Rava P.
        • Hussain M.M.
        Acquisition of triacylglycerol transfer activity by microsomal triglyceride transfer protein during evolution.
        Biochemistry. 2007; 46: 12263-12274
        • Sellers J.A.
        • Hou L.
        • Athar H.
        • Hussain M.M.
        • Shelness G.S.
        A drosophila microsomal triglyceride transfer protein homolog promotes the assembly and secretion of human apolipoprotein B - implications for human and insect lipid transport and metabolism.
        J Biol Chem. 2003; 278: 20367-20373
        • Rava P.
        • Ojakian G.K.
        • Shelness G.S.
        • Hussain M.M.
        Phospholipid transfer activity of microsomal triacylglycerol transfer protein is sufficient for the assembly and secretion of apolipoprotein B lipoproteins.
        J Biol Chem. 2006; 281: 11019-11027
        • Sakers A.
        • De Siqueira M.K.
        • Seale P.
        • Villanueva C.J.
        Adipose-tissue plasticity in health and disease.
        Cell. 2022; 185: 419-446