TCF7L2 involvement in estradiol- and progesterone-modulated islet and hepatic glucose homeostasis.
To evaluate the role of TCF7L2, a key regulator of glucose homeostasis, in estradiol (E2) and progesterone (P4)-modulated glucose metabolism, mouse insulinoma cells (MIN6) and human liver cancer cells (hepG2 and HUH7) were treated with physiological concentrations of E2 or P4 in the up- and down-regulation of TCF7L2. Insulin/proinsulin secretion was measured in MIN6 cells, while glucose uptake and production were evaluated in liver cancer cells. E2 increased insulin/proinsulin secretion under both basal and stimulated conditions, whereas P4 increased insulin/proinsulin secretion only under glucose-stimulated conditions. An antagonistic effect, possibly concentration-dependent, of E2 and P4 on the regulation of islet glucose metabolism was observed. After E2 or P4 treatment, secretion of insulin/proinsulin was positively correlated with TCF7L2 protein expression. When TCF7L2 was silenced, E2- or P4-promoted insulin/proinsulin secretion was significantly weakened. Under glucotoxicity conditions, overexpression of TCF7L2 increased insulin secretion and processing. In liver cancer cells, E2 or P4 exposure elevated TCF7L2 expression, enhanced the activity of insulin signaling (pAKT/pGSK), reduced PEPCK expression, subsequently increased insulin-stimulated glucose uptake, and decreased glucose production. Silencing TCF7L2 eliminated effects of E2 or P4. In conclusion, TCF7L2 regulates E2- or P4-modulated islet and hepatic glucose metabolism. The results have implications for glucose homeostasis in pregnancy.
Department of Endocrinology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Fengqin
F
Dong
Department of Surgery, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Qi
Q
Ling
Department of Endocrinology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Dan
D
Ye
Department of Endocrinology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Zhe
Z
Zhang
Department of Reproductive Endocrinology, Zhejiang Province People's Hospital, Hangzhou, China.
Jing
J
Shu
Department of Endocrinology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Guoping
G
Chen
Department of Metabolism and Endocrinology, People's Hospital of Fuyang City, Hangzhou, China.
Yang
Y
Fei
Department of Endocrinology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Chengjiang
C
Li
D000818:Animals; D002460:Cell Line; D004958:Estradiol / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D007515:Islets of Langerhans / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D051379:Mice; D011374:Progesterone / Q000378:metabolism*; D058118:Transcription Factor 7-Like 2 Protein / Q000378:metabolism*
C544894:TCF7L2 protein, human; D058118:Transcription Factor 7-Like 2 Protein; D011374:Progesterone; D004958:Estradiol; D005947:Glucose