Self-renewal of pluripotent embryonic stem cells is mediated via activation of STAT3

Abstract

The propagation of embryonic stem (ES) cells in an undifferentiated pluripotent state is dependent on leukemia inhibitory factor (LIF) or related cytokines. These factors act through receptor complexes containing the signal transducer gp130. The downstream mechanisms that lead to ES cell self-renewal have not been delineated, however. In this study, chimeric receptors were introduced into ES cells. Biochemical and functional studies of transfected cells demonstrated a requirement for engagement and activation of the latent trancription factor STAT3. Detailed mutational analyses unexpectedly revealed that the four STAT3 docking sites in gp130 are not functionally equivalent. The role of STAT3 was then investigated using the dominant interfering mutant, STAT3F. ES cells that expressed this molecule constitutively could not be isolated. An episomal supertransfection strategy was therefore used to enable the consequences of STAT3F expression to be examined. In addition, an inducible STAT3F transgene was generated. In both cases, expression of STAT3F in ES cells growing in the presence of LIF specifically abrogated self-renewal and promoted differentiation. These complementary approaches establish that STAT3 plays a central role in the maintenance of the pluripotential stem cell phenotype. This contrasts with the involvement of STAT3 in the induction of differentiation in somatic cell types. Cell type-specific interpretation of STAT3 activation thus appears to be pivotal to the diverse developmental effects of the LIF family of cytokines. Identification of STAT3 as a key transcriptional determinant of ES cell self-renewal represents a first step in the molecular characterization of pluripotency.

LIF-Induced STAT3 Signaling in Murine versus Human Embryonal Carcinoma (EC) Cells

“…As a consequence, mouse ES cells can now be cultured in the absence of embryonal fibroblast feeder-cell layers when LIF is administered to the medium [5][6][7][8]. However, human ES cells do not respond to LIF in a similar fashion and still require feeder-cell layers for support [27].…”

“…Mouse ES cells can be maintained in an undifferentiated state when cultured on fibroblast feeder cell layers or in the presence of leukemia inhibitory factor (LIF) on gelatin-coated tissue culture dishes [5][6][7][8]. LIF belongs to the interleukin (IL)-6 family of cytokines, which also includes oncostatin M, ciliary neurotropic factor, IL-11, cardiotrophin, and IL-6 [9].…”

JDP2 suppresses adipocyte differentiation by regulating histone acetylation

“…The targeting vector (pTV-2) was constructed by subcloning a 5.5-kbp EcoRV/XbaI fragment (located in the 5 0 -upstream region of the gene) and a 2.3-kbp PstI/SalI fragment (located in intron 1) in the pPNT vector 30 as the 5 0 -and 3 0 -homologous regions, respectively. The NotIlinearized targeting vector was introduced by electroporation into E14tg2a ES cells 31 and transformed cells were selected in the presence of 200 mg/ml G418. Resistant colonies were subjected to Southern blotting analysis.…”

Interleukin-6 and oncostatin M-induced growth inhibition of human A375 melanoma cells is STAT-dependent and involves upregulation of the cyclin-dependent kinase inhibitor p27/Kip1

“…In M1 cells, at least, IFNg-responses which depend on Jak1 and Jak2 are not a ected by the overexpression of dominant negative STAT3 . Also in other cellular systems STAT3 is essential for the function of IL-6-type cytokines: for the survival of transfected BAF ± B03 pro-B-cells , for the di erentiation of promyelocytic M1 cells to macrophage-like cells (Minami et al, 1996;Nakajima et al, 1996;Yamanaka et al, 1996) and for the proliferation and maintenance of pluripotency of embryonic stem cells (Boeuf et al, 1997;Niwa et al, 1998). However, not all IL-6 e ects depend on STAT3: neurite outgrowth of PC12 pheochromocytoma cells needs signals via Y759 leading to activation of the tyrosine phosphatase SHP-2 and in turn to MAP kinase activation.…”

“…Myeloid M1 cells required functional STAT3 to di erentiate into macrophage-like cells (Minami et al, 1996;Nakajima et al, 1996). The inhibition of differentiation and maintenance of pluripotency of embryonic stem cells cultured in the presence of LIF similarly depended on STAT3 (Boeuf et al, 1997;Niwa et al, 1998). Growth of transfected BAF ± B03 pro-B cells needed the contribution of both signals derived from gp130: STATs induced anti-apoptotic factors, whereas MAP kinase activation was necessary for proliferation .…”