Dr. Janet Rossant

Stem Cells and Early Lineage Development

Janet Rossant 2008. Stem Cells and Early Lineage Development. Cell 132.

Cheryle A. Se´ guin, Jonathan S. Draper, Andras Nagy, and Janet Rossant 2008. Establishment of Endoderm Progenitors by SOX Transcription Factor Expressionin Human Embryonic Stem Cells. Cell Stem Cell 3, 182–195.

Question 1

Please tell us a bit about yourself and your research and how you got started in the field of stem cells.

Michael Barresi

Question 2

What are the major differences when comparing the study and use of Mouse stem cells and human stem cells? How much more expensive is it to work with human stem cells and how different are the techniques when working with human samples?

Beck Jacobson

Question 3

What might explain why the EpiSC’s (from a mouse) expressed gene profiles and transcription factors that were closer to human ES cells than to mouse ES cells? (This was a reported finding on page 529 of the “Stem Cells and Early Lineage Development” review article, but how can it be explained?)

Hiba Jamil

Question 4

Based on your paper it seems clear that Sox7 and Sox17 promote HESC down a path of differentiation toward ExEn and DE respectively. However, how confident are you that these overexpression models do in fact produce identical ExEn or DE cell types as compared to their in vivo equivalents? How have the standards for defining derived HESC as a specific cell type changed over the years? Lastly, in light of all the growth factors, cell to cell contacts, and physical nature of the embryo that all together influence the differentiation of a particular cell fate, how is it possible that one transcription factor can produce specific endodermal lineages in vitro?

Alexandra Sobhani

Question 5

Can you please explain your support for your hypothesis that cell lines derived from epiblast progenitors of the blastocyst are more restricted in developmental potential than those derived from progenitors of later gastrulating embryos.

Jamie Moody

Question 6

You stated that SOX7 O/E injection into HESC restricted lineage specification while SOX17 O/E injection demonstrated multilineage differentation in vivo. What would you hypothesize overexpression of both SOX7 and SOX17 in the same cell line would do, seeing as you demonstrated that SOX7 O/E cell lines express the transcription factor Sox17?

Kimberly Johnson

Question 7

Activin promoted Sox 17 expression in HESCs yet it was still dispensible for hepatic differentiation from HESC. Could you please explain Activin’s role in HESC differentiation?

Alyssa Zachariah

Question 8

FGF signaling plays two specific roles in ES cell and TS cells of the mouse blastocyst but in human cells, these roles are reversed. The autocrine action of FGF was suggested to be responsible for ES cell differentiation in mice – What do we know about the signaling of FGF in HESCs?

Tarja De Soysa

Question 9

Based on your knowledge and experience, what could convince the general public that ESCs are a more optimal source for stem cell therapies, rather than iPS cells or somatic cell nuclear transfer? In other words, disregarding the ethical issues behind them, what would you define as some potentially superior but less obvious characteristics of ESCs that iPS and SCNT cells lack?

Elyse Macksoud

Question 10

In the global context, how easy is it to find funding for and perform embryonic stem cell research in Canada as compared to other countries such as the U.S., Korea, or England to name a few? How do restrictions differ?

Kathryn Gorski

Question 11

When do you believe life begins? Do you think that this distinction should differ between species?

Beck Jacobson (and Hiba Jamil)

Question 12

Can you tell us a bit as to what led to your success in science particular as it related to being a woman in science and the obstacle that might have presented over the years?

Michael Barresi