Differences in Nuclear Signaling by Leukemia Inhibitory Factor and Interferon-γ: The Role of STAT Proteins in Regulating Vasoactive Intestinal Peptide Gene Expression

Homeobox (Hox) genes encode a family of transcription factors that regulate embryonic patterning and organogenesis. In embryos, alterations of the normal pattern of Hox gene expression result in homeotic transformations and malformations. Disruption of theHoxa1gene, the most 3′ member of the Hoxa cluster and a retinoic acid (RA) direct target gene, results in abnormal ossification of the skull, hindbrain, and inner ear deficiencies, and neonatal death. We have generated Hoxa1-/-embryonic stem (ES) cells (named Hoxa1-15) from Hoxa1-/-mutant blastocysts to study the Hoxa1 signaling pathway. We have characterized in detail these Hoxa1-/-ES cells by performing microarray analyses, and by this technique we have identified a number of putative Hoxa-1 target genes, including genes involved in bone development (e.g. Col1a1,Postn/Osf2, and the bone sialoprotein gene orBSP), genes that are expressed in the developing brain (e.g. Nnat,Wnt3a,BDNF,RhoB, andGbx2), and genes involved in various cellular processes (e.g. M-RAS,Sox17,Cdkn2b,LamA1,Col4a1,Foxa2,Foxq1,Klf5, andIgf2). Cell proliferation assays and Northern blot analyses of a number of ES cell markers (e.g. Rex1,Oct3/4,Fgf4, andBmp4) suggest that the Hoxa1 protein plays a role in the inhibition of cell proliferation by RA in ES cells. Additionally, Hoxa1-/-ES cells express high levels of various endodermal markers, includingGata4andDab2, and express much lessFgf5after leukemia inhibitory factor (LIF) withdrawal. Finally, we propose a model in which the Hoxa1 protein mediates repression of endodermal differentiation while promoting expression of ectodermal and mesodermal characteristics.

Download Full-text

Transgenic Expression of Leukemia Inhibitory Factor Inhibits Both Rod and Cone Gene Expression

Retinal Degenerative Diseases - Advances in Experimental Medicine and Biology ◽

10.1007/0-387-32442-9_22 ◽

2007 ◽

pp. 147-153

Author(s):

John D. Ash1 ◽

Dianca R. Graham1

Keyword(s):

Gene Expression ◽

Leukemia Inhibitory Factor ◽

Inhibitory Factor ◽

Transgenic Expression

Download Full-text

A functional role of the membrane-proximal extracellular domains of the signal transducer gp130 in heterodimerization with the leukemia inhibitory factor receptor

European Journal of Biochemistry ◽

10.1046/j.1432-1033.2002.02941.x ◽

2002 ◽

Vol 269 (11) ◽

pp. 2716-2726 ◽

Cited By ~ 28

Author(s):

Andreas Timmermann ◽

Andrea Küster ◽

Ingo Kurth ◽

Peter C. Heinrich ◽

Gerhard Müller-Newen

Keyword(s):

Leukemia Inhibitory Factor ◽

Functional Role ◽

Inhibitory Factor ◽

Signal Transducer ◽

Leukemia Inhibitory Factor Receptor ◽

Extracellular Domains

Download Full-text

272 LEUKEMIA INHIBITORY FACTOR SIGNALING PATHWAY IN PIG PARTHENOGENETIC PLURIPOTENT CELLS

Reproduction Fertility and Development ◽

10.1071/rdv21n1ab272 ◽

2009 ◽

Vol 21 (1) ◽

pp. 233

Author(s):

T. A. L. Brevini ◽

G. Pennarossa ◽

S. Antonini ◽

F. Gandolfi

Keyword(s):

Molecular Markers ◽

Signaling Pathway ◽

Leukemia Inhibitory Factor ◽

Embryonic Stem ◽

Embryoid Bodies ◽

Inhibitory Factor ◽

Germ Layers ◽

Undifferentiated State ◽

Undifferentiated Cells

Leukemia inhibitory factor (LIF), its receptor heterodimer (LRβ-gp130), and the related signal transducer and activator of transcription-3 (STAT3) constitute a system controlling self-renewal and pluripotency of embryonic stem cells (ESC) in the mouse, where LIF withdrawal or direct inhibition of STAT3 causes ESC differentiation. By contrast, several studies have demonstrated that LIF is not required to maintain human ESC pluripotency. Scattered information is available in other species, and data on the role of LIF in pig ESC are scanty. The aims of the present study were (a) to characterize the expression profile of gp130, LRβ, and STAT3 in pig parthenogenetic cell lines (ppC), previously derived in our laboratory and shown to be positive for the main pluripotency related markers; (b) to evaluate the role of LIF pathway in maintaining the pluripotency of these cells. To this purpose, ppC were cultured as previously described (Brevini et al. 2007 Theriogenology 68, 206–214) and screened by RT-PCR for the two LIF receptor subunits (LRβ and gp130) and STAT3. Pig granulosa cells were used as positive controls. To better investigate the possible role of LIF in maintenance of pluripotency in ppC, the formation of embryoid bodies (EB) was induced in the presence or in the absence of the cytokine. Undifferentiated cells were cultured in hanging drops either with or without LIF for 12 days. The EB formation and the expression of molecular markers specific for the three germ layers was evaluated at the end of the differentiation period. Molecular analysis allowed us to detect transcription of STAT3, whereas no signal for LRβ and gp130 was detected in ppC. These results seem to indicate that LIF does not play a role in the maintenance of pluripotency in the pig. However, after removal of LIF, ppC routinely formed EB that expressed molecular markers specific for the three germ layers. On the other hand, when LIF was added to the differentiation medium, pig cells were unable to form EB. They kept proliferating in an undifferentiated state, and no expression of molecular markers specific for the three germ layers was detected. Moreover, when re-plated on inactivated feeder-layers, they formed distinct colonies that maintained expression of pluripotency markers. Our results show that a role of LIF in pluripotency maintenance through a classical LRβ-gp130 and STAT3 activation pathway is unlikely. However, interaction with an alternative nonclassical activation signaling pathway cannot be ruled out. Indeed, the presence of the cytokine in the medium used for differentiation experiments actively inhibited EB formation, indicating a possible role in preventing differentiation in the porcine species. Further studies are needed to elucidate these aspects. Supported by: PRIN2005; PRIN2006; First 2006; First2007.

Download Full-text