Role of HIF-1alpha and VEGF in human mesenchymal stem cell proliferation by 17beta-estradiol: involvement of PKC, PI3K/Akt, and MAPKs.
17beta-Estradiol (E(2)) is a steroid hormone well known for its roles in the regulation of various cell functions. However, the precise role that E(2) plays in the proliferation of human mesenchymal stem cells (hMSCs) has not been completely elucidated. In the present study, we examined the effects of E(2) on cell proliferation and the related signaling pathways using hMSCs. We showed that E(2), at > or =10(-9) M, significantly increased [3H]thymidine incorporation after 24 h of incubation, and E(2) also increased [3H]thymidine incorporation at >6 h. Also, E(2) significantly increased the percentage of the cell population in the S phase based on FACS analysis. Moreover, E(2) increased estrogen receptor (ER), PKC, phosphatidylinositol 3-kinase (PI3K)/Akt, and MAPK phosphorylation. Subsequently, these signaling molecules were involved in an E(2)-induced increase of [3H]thymidine incorporation. E(2) also increased hypoxia-inducible factor (HIF)-1alpha and VEGF protein levels. These levels of protein expression were inhibited by ICI-182,780 (10(-6) M, an ER antagonist), staurosporine and bisindolylmaleimide I (10(-6) M, a PKC inhibitor), LY-294002 (10(-6) M, a PI3K inhibitor), Akt inhibitor (10(-5) M), SP-600125 (10(-6) M, a SAPK/JNK inhibitor), and PD-98059 (10(-5) M, a p44/42 MAPKs inhibitor). In addition, HIF-1alpha small interfering (si)RNA and ICI-182,780 inhibited E(2)-induced VEGF expression and cell proliferation. VEGF siRNA also significantly inhibited E(2)-induced cell proliferation. In conclusion, E(2) partially stimulated hMSC proliferation via HIF-1alpha activation and VEGF expression through PKC, PI3K/Akt, and MAPK pathways.
Yun
Seung Pil
SP
Dept. of Veterinary Physiology, College of Veterinary Medicine, Chonnam National Univ., Gwangju 500-757, Korea. hjhan@chonnam.ac.kr.
Lee
Min Yong
MY
Ryu
Jung Min
JM
Song
Chang Hun
CH
Han
Ho Jae
HJ
D002453:Cell Cycle; D049109:Cell Proliferation; D002478:Cells, Cultured; D004958:Estradiol / Q000378:metabolism*; D004965:Estrogen Antagonists / Q000494:pharmacology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000201:enzymology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D034622:RNA Interference; D011960:Receptors, Estrogen / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D004958:Estradiol; D004965:Estrogen Antagonists; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D011960:Receptors, Estrogen; D042461:Vascular Endothelial Growth Factor A; C497442:HIF1A protein, human; C467484:VEGFA protein, human