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Sterol O‐acyltransferase 1 enhances cholesterol esterification via cyclic AMP‐dependent pathway in the yolk sac membrane endodermal epithelial cells
Author(s) -
Lin HanJen,
Wang SiouHuei,
Chen YuJen,
Mersmann Harry John,
Ding ShihTorng
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.948.2
Subject(s) - ibmx , endocrinology , medicine , forskolin , biology , yolk , lipid droplet , sterol , cholesterol , microbiology and biotechnology , chemistry , ecology , stimulation
During avian embryonic development, absorptions of nutrients is mainly responsible by endodermal epithelial cells (EECs) in the yolk sac membrane (YSM). Yolk lipids are actively absorbed in late stages of incubation. Sterol O‐acyltransferase (SOAT), regulating the cholesterol esterification with long‐chain fatty acid, is the key for lipid utilization during embryonic development. Expressions of SOAT1 are higher than SOAT2 in YSM during embryonic development of Japanese quail, we hypothesized that SOAT1 is greatly involved to mediate uptake of free fatty acid and yolk cholesterol into EECs, and also responsible for absorption and transportation of lipids into developing embryos. Treatments of glucagon, isobutylmethylxanthine (IBMX), a phosphodiesterase inhibitor for increasing cyclic AMP (cAMP) concentration, and low glucose increased SOAT1 mRNA expression in EECs and hepatocytes, suggesting that SOAT1 is regulated by a cAMP‐dependent pathway. Expression of SOAT1 was increased by adenylate cyclase activator (forskolin) and cAMP analog (dibutyryl‐cAMP) treatments in EECs and hepatocytes. Furthermore, the protein kinase A (PKA) activity was increased by IBMX treatment, whereas co‐treatment of PKA inhibitor, H89, negated the increase in PKA activity. Cyclic AMP‐induced EECs had higher activity of cholesterol esterification and thereby more intracellular lipids than untreated EECs. In conclusion, expressions of SOAT1 is regulated via cAMP‐dependent pathway, therefore, factors that regulate PKA will increase the expression of SOAT1 to improve the utilization of lipids in the EECs and modify embryonic growth. Support or Funding Information Sterol O‐acyltransferase 1, cholesteryl ester, cAMP‐dependent pathway, yolk sac membrane, avian embryos