Aberrant expression of leptin in human endometriotic stromal cells is induced by elevated levels of hypoxia inducible factor-1alpha.
Elevated expression of leptin in endometriotic tissue results in an increase in stromal cell proliferation and may contribute to the development of endometriosis. However, the underlying mechanism responsible for aberrant expression of leptin is not known. We hypothesize that aberrant expression of leptin in endometriotic stroma may be regulated by increased levels of hypoxia-inducible factor-1alpha (HIF-1alpha), the master transcription factor that controls gene expression in response to hypoxia. Herein we show that the mRNA and protein levels of HIF-1alpha were greater in ectopic endometriotic tissue compared with its eutopic counterpart. Exposure of eutopic endometrial stromal cells under hypoxic conditions or treated with desferrioxamine (DFO, chemical hypoxia) resulted in a time-dependent increase in leptin gene expression. A promoter activity assay demonstrated that HIF-1alpha induced leptin promoter activity after DFO treatment. Chromatin immunoprecipitation assay further demonstrated that binding of HIF-1alpha to leptin promoter was evident after DFO treatment. Finally, depletion of HIF-1alpha by short interference RNA abolished leptin expression in ectopic endometriotic stromal cells. Taken together, our data demonstrate that aberrant expression of leptin in ectopic endometriotic stromal cells is induced, at least in part, by an elevated level of HIF-1alpha in these cells, providing new insights into the etiology of endometriosis.
Wu
Meng-Hsing
MH
Department of Obstetrics & Gynecology, Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 701, Taiwan, Republic of China.
Chen
Ko-Fan
KF
Lin
Shih-Chieh
SC
Lgu
Chun-Wun
CW
Tsai
Shaw-Jenq
SJ
D000328:Adult; D015687:Cell Hypoxia; D002478:Cells, Cultured; D003676:Deferoxamine / Q000494:pharmacology; D004715:Endometriosis / Q000209:etiology* / Q000378:metabolism; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020738:Leptin / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000494:pharmacology; D017262:Siderophores / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D020738:Leptin; D034741:RNA, Small Interfering; D017262:Siderophores; D003676:Deferoxamine