The environmental light influences the circulatory levels of retinoic acid and associates with hepatic lipid metabolism.
Environmental light is involved in the regulation of photochemical reaction in mouse retina. It remains unclear whether light-mediated increase in all-trans retinoic acid (ATRA) synthesis in retina will result in altering the circulatory levels of ATRA and regulating downstream gene expression and physiological function. Here we showed circulatory levels of ATRA decreased in mice under constant darkness and elevated by light exposure. Fat gene pancreatic lipase-related protein 2 (mPlrp2) and its partner procolipase (mClps), but not hepatic lipase (mHl), activated in livers for responding to lack of light illuminating. Light-triggered alterations in circulatory ATRA levels regulated ecto-5'-nucleotidase gene expression by retinoic acid receptor retinoic acid receptor-alpha and modulated 5'-AMP levels in blood and were associated with mPlrp2 and mClps expression in the livers. Mice deficient in adenosine receptors displayed mPlrp2 and mClps expression in livers under 12-h light, 12-h dark cycles. Caffeine blocked adenosine receptors and induced hepatic mPlrp2 and mClps expression in wild-type mice. Mice activated in hepatic mPlrp2 and mClps expression lowered hepatic and serum lipid levels and markedly elevated circulatory levels of all-trans retinol. Our results suggest environmental light influence hepatic lipid homeostasis by light-modulated retinoic acid signaling associated with mPlrp2 and mClps gene expression in livers.
Pang
Wenqiang
W
Center for Molecular Metabolism, Nanjing University of Science and Technology, 200 Xiaolinwei, Nanjing 210094, China.
Li
Chunying
C
Zhao
Yue
Y
Wang
Shiming
S
Dong
Wei
W
Jiang
Pengjiu
P
Zhang
Jianfa
J
D000818:Animals; D015152:Blotting, Northern; D002851:Chromatography, High Pressure Liquid; D003089:Colipases / Q000235:genetics; D004792:Enzyme Precursors / Q000235:genetics; D015870:Gene Expression / Q000528:radiation effects; D008027:Light; D008049:Lipase / Q000235:genetics; D050356:Lipid Metabolism / Q000502:physiology / Q000528:radiation effects*; D008099:Liver / Q000378:metabolism / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008954:Models, Biological; D018047:Receptors, Purinergic P1 / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014212:Tretinoin / Q000097:blood*
D003089:Colipases; D004792:Enzyme Precursors; D018047:Receptors, Purinergic P1; D014212:Tretinoin; C037107:procolipase; D008049:Lipase; C075988:pancreatic lipase related protein 2