Hormone-sensitive Lipase and Monoglyceride Lipase Activities in Adipose Tissue

Vaughan, Martha; Berger, Jacob E.; Steinberg, Daniel

doi:10.1016/s0021-9258(18)51692-6

Cited by 456 publications

(33 citation statements)

References 16 publications

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“…The current study was undertaken to examine the intracellular signaling events that lead to LH-induced progesterone biosynthesis in steroidogenic small luteal cells. Lipid droplets and HSL have been extensively studied in adipose tissue 25,26,29,37 and to a lesser extent in the adrenal, 29,30,42 testis, 33,41 and granulosa cells of the rat ovary, 34 however, the relationship between HSL and lipid droplets is poorly understood in the corpus luteum, a transient but highly steroidogenic endocrine gland required for the establishment and maintenance of pregnancy. Using primary cultures of steroidogenic small luteal cells, we report that LH via cAMP/PKA signaling regulates the phosphorylation and the localization of HSL on lipid droplets.…”

Section: Discussionmentioning

confidence: 99%

Trafficking of cholesterol from lipid droplets to mitochondria in bovine luteal cells: Acute control of progesterone synthesis

et al. 2020

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The corpus luteum is a transient endocrine gland that synthesizes and secretes the steroid hormone, progesterone, which is vital for establishment and maintenance of pregnancy. Luteinizing hormone (LH) via activation of protein kinase A (PKA) acutely stimulates luteal progesterone synthesis via a complex process, converting cholesterol via a series of enzymatic reactions, into progesterone. Lipid droplets in steroidogenic luteal cells store cholesterol in the form of cholesterol esters, which are postulated to provide substrate for steroidogenesis. Early enzymatic studies showed that hormone sensitive lipase (HSL) hydrolyzes luteal cholesterol esters. In this study, we tested whether HSL is a critical mediator of the acute actions of LH on luteal progesterone production. Using LH-responsive bovine small luteal cells our results reveal that LH, forskolin, and 8-Br cAMP-induced PKA-dependent phosphorylation of HSL at Ser563 and Ser660, events known to promote HSL activity. Small molecule inhibition of HSL activity and siRNA-mediated knock down of HSL abrogated LH-induced progesterone production. Moreover, western blotting and confocal microscopy revealed that LH stimulates phosphorylation and translocation of HSL to lipid droplets. Furthermore, LH increased trafficking of cholesterol from the lipid droplets to the mitochondria, which was dependent on both PKA and HSL activation. Taken together, these findings identify a PKA/HSL signaling pathway in luteal cells in response to LH and demonstrate the dynamic relationship between PKA, HSL, and lipid droplets in luteal progesterone synthesis.

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Section: Discussionmentioning

confidence: 99%

Trafficking of cholesterol from lipid droplets to mitochondria in bovine luteal cells: Acute control of progesterone synthesis

et al. 2020

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“…It is widely accepted that lipolytic hormones such as catecholamine, ACTH, and glucagon cause an activation of cAMP-dependent protein kinase that phosphorylates and activates HSL (23,24). The lipolytic action of various lipolytic agents such as forskolin, DBcAMP, and theophylline, is also believed to be mediated by the cAMP cascade (25)(26)(27).…”

Section: Discussionmentioning

confidence: 99%

Relationships between lipolysis induced by various lipolytic agents and hormone-sensitive lipase in rat fat cells

Morimoto

Kameda

Tsujita

et al. 2001

Journal of Lipid Research

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Norepinephrine induced lipolysis in rat fat cells, in vitro, in a time-and concentration-dependent manner, without concomitantly increasing hormone-sensitive lipase (HSL) activity. It also induced, time and concentration dependently, HSL translocation from the cytosol to the lipid droplets in fat cells. Isoproterenol, forskolin, dibutyryl cyclic AMP, and theophylline also induced lipolysis in fat cells, but did not stimulate HSL activity. These agents also induced HSL translocation from the cytosol to the lipid droplets in fat cells: about 80% to 90% of all HSL was located in lipid droplets after incubation for 1 h. These results suggest that the critical event in lipolytic activation of fat cells induced by lipolytic agents is not an increase in the catalytic activity of HSL but translocation of HSL to its substrate on the surfaces of lipid droplets in fat cells. -Morimoto, C., K. Kameda, T. Tsujita, and H. Okuda. Relationships between lipolysis induced by various lipolytic agents and hormone-sensitive lipase in rat fat cells.

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“…LD depletion mainly occurs during cell starvation where two lipolytic enzymes mediate LD breakdown: adipose triacylglycerol lipase (ATGL) converts TG to diglyceride (DG) (Haemmerle et al . 2006 ) and hormone-sensitive lipase (HSL) converts DG to monoglyceride (MG) (Vaughan, Berger and Steinberg 1964 ). The enzyme phospholipase A (PLA), important for LD homeostasis, also hydrolyzes fatty acids (Kim et al .…”

Section: What Is a Lipid Droplet?mentioning

confidence: 99%

Lipid droplets and lipid mediators in viral infection and immunity

Monson

Trenerry

Laws

et al. 2021

FEMS Microbiology Reviews

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Lipid droplets (LDs) contribute to key pathways important for the physiology and pathophysiology of cells. In a homeostatic view, LDs regulate the storage of neutral lipids, protein sequestration, removal of toxic lipids and cellular communication; however, recent advancements in the field show these organelles as essential for various cellular stress response mechanisms, including inflammation and immunity, with LDs acting as hubs that integrate metabolic and inflammatory processes. The accumulation of LDs has become a hallmark of infection, and is often thought to be virally driven; however, recent evidence is pointing to a role for the upregulation of LDs in the production of a successful immune response to viral infection. The fatty acids housed in LDs are also gaining interest due to the role that these lipid species play during viral infection, and their link to the synthesis of bioactive lipid mediators that have been found to have a very complex role in viral infection. This review explores the role of LDs and their subsequent lipid mediators during viral infections and poses a paradigm shift in thinking in the field, whereby LDs may play pivotal roles in protecting the host against viral infection.

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Hormone-sensitive Lipase and Monoglyceride Lipase Activities in Adipose Tissue

Cited by 456 publications

References 16 publications

Trafficking of cholesterol from lipid droplets to mitochondria in bovine luteal cells: Acute control of progesterone synthesis

Trafficking of cholesterol from lipid droplets to mitochondria in bovine luteal cells: Acute control of progesterone synthesis

Relationships between lipolysis induced by various lipolytic agents and hormone-sensitive lipase in rat fat cells

Lipid droplets and lipid mediators in viral infection and immunity

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