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Lan YL, Lou JC, Lyu W, Zhang B. Update on the synergistic effect of HSL and insulin in the treatment of metabolic disorders. Ther Adv Endocrinol Metab 2019; 10:2042018819877300. [PMID: 31565213 PMCID: PMC6755629 DOI: 10.1177/2042018819877300] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/26/2019] [Indexed: 12/12/2022] Open
Abstract
Hormone-sensitive lipase (HSL) is one of the three lipases in adipose tissue present during periods of energy demand. HSL is tightly controlled by insulin regulation via the central and peripheral systems. The suppressive effects of insulin on HSL are also associated with complex crosstalk with other pathways in the metabolic network. Because impaired insulin action is the driving force behind the pathogenesis of diabetes and other metabolic complications, elucidation of the intricate relationships between HSL and insulin may provide an in-depth understanding of these pandemic diseases and potentially identify strategies to inhibit disease development. Insulin not only differentially regulates HSL isoform transcription but also post-transcriptionally affects HSL phosphorylation by stimulating PKA and endothelin (ET-1), and controls its expression indirectly via regulating the activity of growth hormone (GH). In addition, a rapid elevation of HSL levels was detected after insulin injection in patients, which suggests that the inhibitory effects of insulin on HSL can be overridden by insulin-induced hypoglycemia. Conversely, individuals with hereditary HSL deficiency, and animals with experimental HSL deletion, showed major disruptions in mRNA/protein expression in insulin signaling pathways, ultimately leading to insulin resistance, diabetes, and fatty liver. Notably, HSL inactivation could cause insulin-independent fatty liver, while insulin resistance induced by HSL deficiency may further aggravate disease progression. The common beliefs that HSL is the overall rate-limiting enzyme in lipolysis and that insulin is an inhibitor of HSL have been challenged by recent discoveries; therefore, a renewed examination of their relationships is required. In this review, by analyzing current data related to the role of, and mutual regulation between, HSL and insulin and discussing unanswered questions and disparities in different lines of studies, the authors intend to shed light on our understanding of lipid metabolism and provide a rational basis for future research in drug development.
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Affiliation(s)
- Yu-Long Lan
- Department of Neurosurgery, The Second
Affiliated Hospital of Dalian Medical University, Dalian, China
- Department of Neurosurgery, Shenzhen People’s
Hospital, Shenzhen, China
- Department of Pharmacy, Dalian Medical
University, Dalian, China
- Department of Physiology, Dalian Medical
University, Dalian, China
| | - Jia-Cheng Lou
- Department of Neurosurgery, The Second
Affiliated Hospital of Dalian Medical University, Dalian, China
- Department of Neurosurgery, Shenzhen People’s
Hospital, Shenzhen, China
| | - Wen Lyu
- Department of Neurosurgery, Shenzhen People’s
Hospital, Shenzhen, China
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2
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Manna PR, Cohen-Tannoudji J, Counis R, Garner CW, Huhtaniemi I, Kraemer FB, Stocco DM. Mechanisms of action of hormone-sensitive lipase in mouse Leydig cells: its role in the regulation of the steroidogenic acute regulatory protein. J Biol Chem 2013; 288:8505-8518. [PMID: 23362264 DOI: 10.1074/jbc.m112.417873] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Hormone-sensitive lipase (HSL) catalyzes the hydrolysis of cholesteryl esters in steroidogenic tissues and, thus, facilitates cholesterol availability for steroidogenesis. The steroidogenic acute regulatory protein (StAR) controls the rate-limiting step in steroid biosynthesis. However, the modes of action of HSL in the regulation of StAR expression remain obscure. We demonstrate in MA-10 mouse Leydig cells that activation of the protein kinase A (PKA) pathway, by a cAMP analog Bt2cAMP, enhanced expression of HSL and its phosphorylation (P) at Ser-660 and Ser-563, but not at Ser-565, concomitant with increased HSL activity. Phosphorylation and activation of HSL coincided with increases in StAR, P-StAR (Ser-194), and progesterone levels. Inhibition of HSL activity by CAY10499 effectively suppressed Bt2cAMP-induced StAR expression and progesterone synthesis. Targeted silencing of endogenous HSL, with siRNAs, resulted in increased cholesteryl ester levels and decreased cholesterol content in MA-10 cells. Depletion of HSL affected lipoprotein-derived cellular cholesterol influx, diminished the supply of cholesterol to the mitochondria, and resulted in the repression of StAR and P-StAR levels. Cells overexpressing HSL increased the efficacy of liver X receptor (LXR) ligands on StAR expression and steroid synthesis, suggesting HSL-mediated steroidogenesis entails enhanced oxysterol production. Conversely, cells deficient in LXRs exhibited decreased HSL responsiveness. Furthermore, an increase in HSL was correlated with the LXR target genes, steroid receptor element-binding protein 1c and ATP binding cassette transporter A1, demonstrating HSL-dependent regulation of steroidogenesis predominantly involves LXR signaling. LXRs interact/cooperate with RXRs and result in the activation of StAR gene transcription. These findings provide novel insight and demonstrate the molecular events by which HSL acts to drive cAMP/PKA-mediated regulation of StAR expression and steroidogenesis in mouse Leydig cells.
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Affiliation(s)
- Pulak R Manna
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Joëlle Cohen-Tannoudji
- University Paris Diderot, Sorbonne Paris Cité, Physiologie de l'axe gonadotrope, Biologie Fonctionnelle et Adaptative, EAC CNRS 4413, Paris, France
| | - Raymond Counis
- University Paris Diderot, Sorbonne Paris Cité, Physiologie de l'axe gonadotrope, Biologie Fonctionnelle et Adaptative, EAC CNRS 4413, Paris, France
| | - Charles W Garner
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Ilpo Huhtaniemi
- Institute of Reproductive and Developmental Biology, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - Fredric B Kraemer
- Department of Medicine, Veterans Affairs Palo Alto Heath Care System, Palo Alto, California 94304
| | - Douglas M Stocco
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430.
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Lampidonis AD, Rogdakis E, Voutsinas GE, Stravopodis DJ. The resurgence of Hormone-Sensitive Lipase (HSL) in mammalian lipolysis. Gene 2011; 477:1-11. [PMID: 21241784 DOI: 10.1016/j.gene.2011.01.007] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/22/2010] [Accepted: 01/07/2011] [Indexed: 12/13/2022]
Abstract
The ability to store energy in the form of energy-dense triacylglycerol and to mobilize these stores rapidly during periods of low carbohydrate availability or throughout the strong metabolic demand is a highly conserved process, absolutely essential for survival. In the industrialized world the regulation of this pathway is viewed as an important therapeutic target for disease prevention. Adipose tissue lipolysis is a catabolic process leading to the breakdown of triacylglycerols stored in fat cells, and release of fatty acids and glycerol. Mobilization of adipose tissue fat is mediated by the MGL, HSL and ATGL, similarly functioning enzymes. ATGL initiates lipolysis followed by the actions of HSL on diacylglycerol, and MGL on monoacylglycerol. HSL is regulated by reversible phosphorylation on five critical residues. Phosphorylation alone, however, is not enough to activate HSL. Probably, conformational alterations and a translocation from the cytoplasm to lipid droplets are also involved. In accordance, Perilipin functions as a master regulator of lipolysis, protecting or exposing the triacylglycerol core of a lipid droplet to lipases. The prototype processes of hormonal lipolytic control are the β-adrenergic stimulation and suppression by insulin, both of which affect cytoplasmic cyclic AMP levels. Lipolysis in adipocytes is an important process in the management of body energy reserves. Its deregulation may contribute to the symptoms of type 2 diabetes mellitus and other pathological situations. We, herein, discuss the metabolic regulation and function of lipases mediating mammalian lipolysis with a focus on HSL, quoting newly identified members of the lipolytic proteome.
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Affiliation(s)
- Antonis D Lampidonis
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Zografou, 157 84 Athens, Greece
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Rosenbaum AI, Rujoi M, Huang AY, Du H, Grabowski GA, Maxfield FR. Chemical screen to reduce sterol accumulation in Niemann-Pick C disease cells identifies novel lysosomal acid lipase inhibitors. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:1155-65. [PMID: 19699313 DOI: 10.1016/j.bbalip.2009.08.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 08/05/2009] [Accepted: 08/07/2009] [Indexed: 01/23/2023]
Abstract
Niemann-Pick C disease (NPC) is a lysosomal storage disorder causing abnormal accumulation of unesterified free cholesterol in lysosomal storage organelles. High content phenotypic microscopy chemical screens in both human and hamster NPC-deficient cells have identified several compounds that partially revert the NPC phenotype. Cell biological and biochemical studies show that several of these molecules inhibit lysosomal acid lipase, the enzyme that hydrolyzes LDL-derived triacylglycerol and cholesteryl esters. The effects of reduced lysosomal acid lipase activity in lowering cholesterol accumulation in NPC mutant cells were verified by RNAi-mediated knockdown of lysosomal acid lipase in NPC1-deficient human fibroblasts. This work demonstrates the utility of phenotypic cellular screens as a means to identify molecular targets for altering a complex process such as intracellular cholesterol trafficking and metabolism.
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Affiliation(s)
- Anton I Rosenbaum
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
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Lampidonis AD, Stravopodis DJ, Voutsinas GE, Messini-Nikolaki N, Stefos GC, Margaritis LH, Argyrokastritis A, Bizelis I, Rogdakis E. Cloning and functional characterization of the 5′ regulatory region of ovine Hormone Sensitive Lipase (HSL) gene. Gene 2008; 427:65-79. [DOI: 10.1016/j.gene.2008.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 06/29/2008] [Accepted: 09/01/2008] [Indexed: 01/24/2023]
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Lampidonis AD, Argyrokastritis A, Stravopodis DJ, Voutsinas GE, Ntouroupi TG, Margaritis LH, Bizelis I, Rogdakis E. Cloning and functional characterization of the ovine Hormone Sensitive Lipase (HSL) full-length cDNAs: An integrated approach. Gene 2008; 416:30-43. [DOI: 10.1016/j.gene.2008.02.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 02/20/2008] [Accepted: 02/21/2008] [Indexed: 10/22/2022]
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Cherradi N, Pardo B, Greenberg AS, Kraemer FB, Capponi AM. Angiotensin II activates cholesterol ester hydrolase in bovine adrenal glomerulosa cells through phosphorylation mediated by p42/p44 mitogen-activated protein kinase. Endocrinology 2003; 144:4905-15. [PMID: 12960096 DOI: 10.1210/en.2003-0325] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In adrenal glomerulosa cells, the stimulation of aldosterone biosynthesis by angiotensin II (Ang II) occurs via activation of the Ca2+ messenger system, increased expression of the steroidogenic acute regulatory protein, and enhanced transfer of cholesterol to the inner mitochondrial membrane. We examined here whether Ang II affects the activity of cholesterol ester hydrolase (CEH), also named hormone-sensitive lipase, the enzyme recruiting cholesterol from intracellular pools, in bovine adrenal glomerulosa cells. In bovine adrenal tissue, CEH activity was detected with characteristics similar to those reported in other tissues (Michaelis constant = 46.3 +/- 6.7 microM, n = 3; maximal velocity = 1 nmol/mg.min). This activity was significantly enhanced in isolated bovine glomerulosa cells challenged for 2 h with 10 nM Ang II (to 149 +/- 11% of controls, n = 3). Similarly, 25 microM forskolin raised CEH activity to 151 +/- 5% of controls (n = 3). This increase in activity of CEH was not due to an increase in the amount of enzyme protein but was associated with an increased phosphorylation of the enzyme to 337 +/- 33% of controls (n = 9, P < 0.0001). Potassium ion (K+) and forskolin also stimulated [32P]orthophosphate incorporation, although to a lesser extent (to 157 +/- 18% and 186 +/- 25% of controls, respectively). On SDS-PAGE, the majority of this radioactivity was associated with a species of 172 kDa, corresponding to a CEH dimer. Both Ang II-induced CEH phosphorylation and pregnenolone production were significantly reduced (to 47 +/- 6% and 50 +/- 8% of controls with Ang II alone, respectively) in the presence of PD098059, an inhibitor of p42/p44 MAPK. Indeed, Ang II challenge led to a rapid 32P incorporation into p42/p44 MAPK. These results demonstrate that, in addition to its known effects on intramitochondrial cholesterol transfer, Ang II also promotes aldosterone biosynthesis by rapidly increasing cholesterol supply to the outer mitochondrial membrane.
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Affiliation(s)
- Nadia Cherradi
- Division of Endocrinology, Diabetology and Nutrition, Department of Internal Medicine, Faculty of Medicine, CH-1211 Geneva, Switzerland
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Tansey JT, Huml AM, Vogt R, Davis KE, Jones JM, Fraser KA, Brasaemle DL, Kimmel AR, Londos C. Functional studies on native and mutated forms of perilipins. A role in protein kinase A-mediated lipolysis of triacylglycerols. J Biol Chem 2003; 278:8401-6. [PMID: 12477720 DOI: 10.1074/jbc.m211005200] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Perilipin A coats the lipid storage droplets in adipocytes and is polyphosphorylated by protein kinase A (PKA); the fact that PKA activates lipolysis in adipocytes suggests a role for perilipins in this process. To assess whether perilipins participate directly in PKA-mediated lipolysis, we have expressed constructs coding for native and mutated forms of the two major splice variants of the perilipin gene, perilipins A and B, in Chinese hamster ovary fibroblasts. Perilipins localize to lipid droplet surfaces and displace the adipose differentiation-related protein that normally coats the droplets in these cells. Perilipin A inhibits triacylglycerol hydrolysis by 87% when PKA is quiescent, but activation of PKA and phosphorylation of perilipin A engenders a 7-fold lipolytic activation. Mutation of PKA sites within the N-terminal region of perilipin abrogates the PKA-mediated lipolytic response. In contrast, perilipin B exerts only minimal protection against lipolysis and is unresponsive to PKA activation. Since Chinese hamster ovary cells contain no PKA-activated lipase, we conclude that the expression of perilipin A alone is sufficient to confer PKA-mediated lipolysis in these cells. Moreover, the data indicate that the unique C-terminal portion of perilipin A is responsible for its protection against lipolysis and that phosphorylation at the N-terminal PKA sites attenuates this protective effect.
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Affiliation(s)
- John T Tansey
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-8028, USA
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Abstract
Luteinization is essential to the success of early gestation. It is the process by which elements of the ovarian follicle, usually including both theca interna and granulosa cells, are provoked by the ovulatory stimulus to develop into the corpus luteum. Although there are significant species differences in luteinization, some elements pervade, including the morphological and functional differentiation to produce and secrete progesterone. There is evidence that luteinization results in granulosa cell exit from the cell cycle. The mechanisms that appear to control luteinization include intracellular signalling pathways, cell adhesion factors, intracellular cholesterol and oxysterols, and perhaps progesterone itself as a paracrine or intracrine regulator. Cell models of luteinization, along with some of the conflicting observations on the luteinization process, are discussed in this review.
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Affiliation(s)
- B D Murphy
- Centre de recherche en reproduction animale, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada J2S 7C6.
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Londos C, Brasaemle DL, Schultz CJ, Adler-Wailes DC, Levin DM, Kimmel AR, Rondinone CM. On the control of lipolysis in adipocytes. Ann N Y Acad Sci 1999; 892:155-68. [PMID: 10842661 DOI: 10.1111/j.1749-6632.1999.tb07794.x] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The lipolytic reaction in adipocytes is one of the most important reactions in the management of bodily energy reserves, and dysregulation of this reaction may contribute to the symptoms of Type 2 diabetes mellitus. Yet, progress on resolving the molecular details of this reaction has been relatively slow. However, recent developments at the molecular level begin to paint a clearer picture of lipolysis and point to a number of unanswered questions. While HSL has long been known to be the rate-limiting enzyme of lipolysis, the mechanism by which HSL attacks the droplet lipids is not yet firmly established. Certainly, the immunocytochemical evidence showing the movement of HSL to the lipid droplet upon stimulation leaves little doubt that this translocation is a key aspect of the lipolytic reaction, but whether or not HSL phosphorylation contributes to the translocation, and at which site(s), is as yet unresolved. It will be important to establish whether there is an activation step in addition to the translocation reaction. The participation of perilipin A is indicated by the findings that this protein can protect neutral lipids within droplets from hydrolysis, but active participation in the lipolytic reaction is yet to be proved. Again, it will be important to determine whether mutations of serine residues of PKA phosphorylation sites of perilipins prevent lipolysis, and whether such modifications abolish the physical changes in the droplet surfaces that accompany lipolysis.
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Affiliation(s)
- C Londos
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-2715, USA.
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