TY - JOUR
T1 - Trafficking of cholesterol from lipid droplets to mitochondria in bovine luteal cells
T2 - Acute control of progesterone synthesis
AU - Plewes, Michele R.
AU - Krause, Crystal
AU - Talbott, Heather A.
AU - Przygrodzka, Emilia
AU - Wood, Jennifer R.
AU - Cupp, Andrea S.
AU - Davis, John S.
N1 - Funding Information:
This project was supported by NIH grants R01 HD087402 and R01HD092263 to JSD, ASC and JRW; USDA, NIFA Grants 2017-67015-26450 to JSD and ASC, 2014-67011-22280 to HAT, and 2018-08068 to MRP; the Department of Veterans Affairs I01 BX004272 to JSD; the Olson Center for Women's Health; and the use of microscope was supported by Center for Cellular Signaling CoBRE-P30GM106397 National Health Institutes. The authors thank Janice Taylor and James Talaska at the University of Nebraska Medical Center, Advanced Microscopy Core Facility for their assistance with microscopy. The use of microscope was supported by Center for Cellular Signaling CoBRE-P30GM106397 from the National Health Institutes. This material is the result of work supported with resources and the use of facilities at the Veterans Affairs Nebraska Western Iowa Health Care System, Omaha, NE.
Funding Information:
This project was supported by NIH grants R01 HD087402 and R01HD092263 to JSD, ASC and JRW; USDA, NIFA Grants 2017‐67015‐26450 to JSD and ASC, 2014‐67011‐22280 to HAT, and 2018‐08068 to MRP; the Department of Veterans Affairs I01 BX004272 to JSD; the Olson Center for Women's Health; and the use of microscope was supported by Center for Cellular Signaling CoBRE‐P30GM106397 National Health Institutes.
Publisher Copyright:
© 2020 Federation of American Societies for Experimental Biology
PY - 2020/8/1
Y1 - 2020/8/1
N2 - 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.
AB - 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.
KW - corpus luteum
KW - hormone sensitive lipase
KW - luteinizing hormone
KW - protein kinase A
KW - steroidogenesis
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U2 - 10.1096/fj.202000671R
DO - 10.1096/fj.202000671R
M3 - Article
C2 - 32614098
AN - SCOPUS:85087288942
VL - 34
SP - 10731
EP - 10750
JO - FASEB Journal
JF - FASEB Journal
SN - 0892-6638
IS - 8
ER -