Animal Reproductive Biology Group

Toshihiko Ezashi

Research Assistant Professor

Phone: 573-882-7793
E-mail: EzashiT@missouri.edu
Address: 440b Life Sciences Center

Education

B.S., Azabu University- Japan
M.S., Azabu University - Japan
Ph.D., Gunma University- Japan
Postdoc, Osaka Bioscience Institute (1992-1995), University of Missouri (1995-1999)

Research Focus

Gene regulation
Embryonic stem cells

Research Description

Ezashi's research focuses on the underlying molecular mechanisms of the pluripotent nature of human embryonic stem (hES) cells. The pluripotent nature of hES cells holds tremendous potential for improving human health.

A major difficulty encountered during in vitro culture of hES cells is their tendency to undergo spontaneous differentiation under standard laboratory conditions. Ezashi is researching why hES cells undergo spontaneous differentiation when exposed to ambient O2 concentration.

Furthermore, the viability of hES cells during cryopreservation is low, resulting in poor recovery of cells upon subsequent thawing. These shortcomings pose significant limitations on the use of hES cells. Ezashi is also interested in the use of hES cells to understand how the trophoectoderm lineage is specified during early embryonic development.

Trophoblast differentiation is the first lineage specification event that occurs during early embryonic development and is critical for subsequent embryonic development. Trophoblast cells ultimately give rise to the placenta. If bone morphogenetic protein (BMP)-4 is added to the hES cell culture media, hES cells show synchronized and progressive differentiation to trophoblast. However, whether BMP-4 is the true or only signal for trophoblast differentiation in vivo remains to be determined. Ezashi has also examined how O2 tension influences differentiation of hES cells to trophoblast. Human embryonic stem cells provide a unique model system for understanding how lineage specification during development may perturb placental development and contribute to pathophysiological conditions such as preeclampsia.

Recent Publications

Ezashi T, Das P, Roberts RM.
Low O2 tensions and the prevention of differentiation of hES cells. Proc Natl Acad Sci U S A. 2005 Mar 29;102(13):4783-8. Epub 2005 Mar 16. PMID: 15772165
Roberts RM, Ezashi T, Das P.
Trophoblast gene expression: transcription factors in the specification of early trophoblast. Reprod Biol Endocrinol. 2004 Jul 5;2:47. Review. PMID: 15236655
Ezashi T, Roberts RM.
Regulation of interferon-tau (IFN-tau) gene promoters by growth factors that target the Ets-2 composite enhancer: a possible model for maternal control of IFN-tau production by the conceptus during early pregnancy. Endocrinology. 2004 Oct;145(10):4452-60. Epub 2004 Jun 24. PMID: 15217985
Roberts RM, Ezashi T, Rosenfeld CS, Ealy AD, Kubisch HM.
Evolution of the interferon tau genes and their promoters, and maternal-trophoblast interactions in control of their expression. Reprod Suppl. 2003;61:239-51. Review. PMID: 14635939
Ghosh D, Ezashi T, Ostrowski MC, Roberts RM.
A central role for Ets-2 in the transcriptional regulation and cyclic adenosine 5'-monophosphate responsiveness of the human chorionic gonadotropin-beta subunit gene. Mol Endocrinol. 2003 Jan;17(1):11-26. PMID: 12511603
Ezashi T, Ghosh D, Roberts RM.
Repression of Ets-2-induced transactivation of the tau interferon promoter by Oct-4. Mol Cell Biol. 2001 Dec;21(23):7883-91. PMID: 11689681
Szafranska B, Miura R, Ghosh D, Ezashi T, Xie S, Roberts RM, Green JA.
Gene for porcine pregnancy-associated glycoprotein 2 (poPAG2): its structural organization and analysis of its promoter. Mol Reprod Dev. 2001 Oct;60(2):137-46. PMID: 11553911
Han CS, Chen Y, Ezashi T, Roberts RM.
Antiviral activities of the soluble extracellular domains of type I interferon receptors. Proc Natl Acad Sci U S A. 2001 May 22;98(11):6138-43. Epub 2001 May 8. PMID: 11344274
Roberts RM, Ealy AD, Alexenko AP, Han CS, Ezashi T.
Trophoblast interferons. Placenta. 1999 May;20(4):259-64. Review. PMID: 10329345
Ezashi T, Ealy AD, Ostrowski MC, Roberts RM.
Control of interferon-tau gene expression by Ets-2. Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):7882-7. PMID: 9653109
A complete list of publications for T Ezashi in PubMed