«This composition patent is a milestone achievement for Novocell and is the culmination of extensive research that opened the door to
the endoderm lineage,» said Fred Middleton, Chairman & Acting CEO of Novocell.
San Diego, CA (March 31, 2009)-- Novocell, Inc., a stem cell engineering company, today announced that it has received U.S. Patent 7,510,876 with claims covering human definitive endoderm cells, an essential cell for generating not only pancreatic type cells, which Novocell is developing for use as a cell therapy for diabetes, but also other
endoderm lineage - derived tissues and organs such as lungs, intestine, liver, thymus and thyroid.
A more recent study showed overlapping expression of nanog with GATA - 6 and a Pdgfra reporter, markers of the primitive
endoderm lineage, from the morula to the 64 cell stages [8], suggesting a gradual transition from a pluripotency program to a committed state.
Here we use a transgenic allele designed to detect low level transcription in the primitive
endoderm lineage as a tool to identify an immediate early endoderm - like ES cell state.
(A) A low concentration of FBS in combination with a high concentration of recombinant Activin A could induce iPS cells of line 11.1 into a definitive
endoderm lineage.
On the other hand, cells of line 4.1 differentiated into
endoderm lineages more easily than cells of line 11.1 (data not shown).
To induce mesoderm and
endoderm lineages from iPS cells, cells were grown as embryoid bodies (EB) in DMEM / F12 with 10 % fetal bovine serum for 2 weeks.
The epiblast is the source of all embryonic tissue and the PrEn the source of both extra-embryonic
endoderm lineages, visceral and parietal.
Not exact matches
When the ESCs had no Chd1 at all, the cells could not differentiate into all of the three germ layers (specifically,
endoderm was not detected, and a preference was found for neuronal
lineages).
Simultaneously, expression of markers for major developmental
lineages, including trophectoderm (Cdx2), ectoderm (Fgf5), mesoderm (T) and
endoderm (Gsc, Sox7 and Afp), was activated (Figure 4B, bottom panel).
However, cells derived from the early epiblast are only able to contribute to embryonic
lineages and not those derived from the PrEn [18]--[20], while PrEn cells can only contribute to their own
lineage by colonizing the visceral and mostly parietal
endoderm in chimera experiments [20]--[22].
In support of this idea, Beddington and Robertson originally observed ES cell contribution to all the extra-embryonic
lineages, but in particular to parietal
endoderm [23].
The Venus positive population does not efficiently contribute to somatic
lineages, appears at the outside of EBs, and has the capacity to colonize the visceral and parietal
endoderm in chimeras.
However, when challenged to differentiate immediately after purification, each exhibits strong
lineage bias, with the
endoderm marker - expressing fraction unexpectedly able to contribute to the extra-embryonic
endoderm in chimeric embryos.
On the other hand, ES cells and cells differentiating into
endoderm and mesoderm
lineages from ES cells express OCT - 4 in mice and humans [66], and SSEA1 expression is found in other type of cells including neural stem cells and mesenchymal stem cells [67], [68].
Mouse embryonic stem cells derived from the epiblast contribute to the somatic
lineages and the germline but are excluded from the extra-embryonic tissues that are derived from the trophectoderm and the primitive
endoderm upon reintroduction to the blastocyst.
It is probable that these cells represent extraembryonic
endoderm, and that they arise directly from stem cells primed to differentiation into this
lineage.