Cardiovascular System ; GATA4 Transcription Factor ; metabolism ; Humans

Gata4 is an important transcription factor in heart development. Gata4 post-transcriptional protein modification regulates transcriptional activity and DNA binding, which in turn affects expression of downstream genes and transcription factors, differentiation of embryonic stem cells and cardiogenesis. This article summarizes the effect of post-transcriptional protein modification on transcriptional activity of Gata4 and the relationship between this effect and congenital heart disease. It was shown that acetylation, phosphorylation and SUMOylation upregulate transcriptional activity, DNA binding, downstream gene expression and embryonic stem cell differentiation. On the other hand, methylation and deacetylation downregulate Gata4 transcriptional activity. Post-transcriptional protein modification of Gata4 is very important in clinical research on congenital and other heart diseases.
Acetylation ; Animals ; GATA4 Transcription Factor ; chemistry ; genetics ; metabolism ; Humans ; Methylation ; Phosphorylation ; Protein Processing, Post-Translational ; Sumoylation

The GATA family proteins are a group of zinc finger transcription factors that are expressed in human and mammalian animals and play an important role in mammalian organ morphogenesis, cell proliferation and sex differentiation. GATA-4 and GATA-6 have been identified in the ovaries and testes of humans, mice, pigs and chickens. GATA-4 contributes to fetal male gonadal development by regulating the genes that mediate Müllerian duct regression and the onset of testosterone production. GATA-4 and GATA-6 are localized in and regulate the function of the ovarian and testicular somatic cells of fetal mice, especially granulosa cells, thecal cells, Sertoli cells and Leydig cells. GATA-4 is also present in the germ cells of fetal and prepubertal mice.
Animals ; Chickens ; Female ; GATA4 Transcription Factor ; metabolism ; GATA6 Transcription Factor ; metabolism ; Humans ; Male ; Mice ; Ovary ; embryology ; Reproduction ; Swine ; Testis ; embryology ; Transcription Factors ; classification

OBJECTIVETo explore the characteristics and distribution of GATA-4 in the testis of male mice.

METHODSParaffin sections were obtained from the testes of 24 male B6SJLF1/J mice, aged 0 day (n = 6), 2 weeks (n = 6), 4 weeks (n = 6) and 6 weeks (n = 6), and the expressions of GATA-4 in the testis were observed by the immunohistochemical ABC method and DAB visualization at different times.

RESULTSPositive expressions of GATA4 were found in the Sertoli cells and Leydig cells of all the mice, but significantly higher in the 4- and 6-week-old than in the 0-day and 2-week-old groups (P < 0.01). And they were also observed in the germ cells of the 4- and 6-week-old mice, significantly higher in the latter than in the former (P < 0.01).

CONCLUSIONGATA-4 exists in the testis of male mice, which has provided a morphological base for sex determination and differentiation and hormone regulation in the testis.

Animals ; Cell Differentiation ; GATA4 Transcription Factor ; metabolism ; Germ Cells ; metabolism ; Leydig Cells ; metabolism ; Male ; Mice ; Sertoli Cells ; metabolism ; Testis ; cytology ; metabolism

OBJECTIVETo investigate the effect of cardiotrophin-1 (CT-1) on the GATA4 expression and related signaling pathways (JAK-STAT3, ERK1/2 and PI3-K) in rat cardiomyocytes.

METHODSUsing semi-quantitative RT-PCR and EMSA, we measured the dose and time dependent effects of CT-1 on GATA4 mRNA and binding activity in cultured rat cardiomyocytes. Parthenolide (a STAT inhibitor), U-0126 (an ERK inhibitor) and LY-294002 (a PI3-K inhibitor) alone or in combination were added to the culture medium to assess the role of above signaling pathways in CT-1 mediated effects.

RESULTSGATA4 mRNA expression significantly increased at 3 h post 0.1 nmol/L CT-1 exposure, peaked at 6 h and remained high till 24 h post exposure. The GATA4 binding activity began to increase at 10 min and peaked at 60 min and returned to baseline level 180 min. Six hours post CT-1 (0.01 nmol/L, 0.1 nmol/L, 1 nmol/L) exposure, the GATA4 mRNA expression increased in a dose-dependent manner. The GATA4 binding activity peaked with 0.1 nmol/L CT-1 and higher dose did not further increase the binding activity. U-0126 increased the GATA4 mRNA expression and enhanced the GATA4 binding activity and these effects could be partially attenuated with addition of Parthenolide. Parthenolide also prevented the increase of GATA4 mRNA and binding activity induced by CT-1. LY-294002 had no effects GATA4 mRNA and binding activity.

CONCLUSIONCT-1 increases the GATA4 mRNA expression and binding activity in rat cardiomyocytes via STAT3/ERK1/2 pathways and these effects are independent of PI3-K pathway.

Animals ; Cell Line ; Cytokines ; pharmacology ; GATA4 Transcription Factor ; biosynthesis ; genetics ; Myocytes, Cardiac ; metabolism ; RNA, Messenger ; biosynthesis ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; STAT3 Transcription Factor ; pharmacology ; Signal Transduction

BACKGROUNDIn a suitable microenvironment, bone marrow mesenchymal stem cells (BMSCs) can transdifferentiate into myocardial cells whose special gene can be expressed as structural proteins. Growth factor (GF) plays an important role in the cell migration, survival and differentiation. However, the effect of GF on the cellular differentiation is not well understood. In this study, the hepatocyte growth factor (HGF) and insulin like growth factor-1 (IGF-1) were used in the mixed culture of BMSCs and myocardial cells and the effects of these growth factors on the GATA-4 expression of BMSCs were investigated.

METHODSBMSCs were isolated from the marrow of rabbit femurs and tibias and foetal rabbit ventricular myocytes were isolated with trypsin sequential digestion. These two kinds of cells were cocultured in a ratio of 1:1 for 6 weeks; cocultured cells with added HGF and IGF-1 were the experimental group. The differentiated BMSCs were collected using the laser capture, microdissection system and their RNA isolated. Immunocytochemical staining, transmission electron microscopy and reverse transcription-polymerase chain reaction were used to evaluate the transformation of the stem cells into cardiomyocytes like cells.

RESULTSWhen cultured separately, BMSCs did not express alpha-actin and the stem cells had many nucleoli. However, when cocultured with cardiomyocytes, BMSCs expressed alpha-actin and the cardiac transcription factor GATA-4 and showed cardiomyocyte like ultrastructure. In comparison with the control group, the experimental group exhibited the enhanced expression level of GATA-4. The GATA-4 expression of BMSCs increased gradually following the addition of HGF and IGF-1, reached the maximal level after two weeks and decreased slightly thereafter.

CONCLUSIONSBMSCs can transdifferentiate into cardiomyocytes like cells and express the cardiac transcription factor GATA-4 after being cocultured with myocardial cells. HGF and IGF-1 can stimulate transdifferentiation of BMSCs into cardiac phenotype and enhance the expression of GATA-4. These results indicate that growth factors have a great potential in clinical cellular therapy.

Animals ; Cell Differentiation ; drug effects ; Coculture Techniques ; GATA4 Transcription Factor ; genetics ; Hepatocyte Growth Factor ; pharmacology ; Insulin-Like Growth Factor I ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Myocytes, Cardiac ; cytology ; metabolism ; Rabbits

OBJECTIVETo investigate the role of homeobox gene Nkx2-5 in cardiac myogenesis.

METHODSTwo P19 cell lines, namely cells transfected with exogenous expression of Nkx2-5 gene and non-transfected cells, were cultured in suspension for 4 days to induce cell aggregation, and the cell aggregates were transferred to the Petri dish for further adherent culture. On days 4, 8, 12 and 16 of adherent culture, the expressions of α-sarcomeric actin (α-SA) and cardiac troponin T (cTnT) protein were detected by immunocytochemistry, and the mRNA expressions of GATA-4, α-myosin heavy chain (α-MHC) and atrial natriuretic factor (ANF) genes by RT-PCR.

RESULTSIn the transfected cells, α-SA and cTnT protein expressions were detected on days 8, 12 and 16 of adhere culture, and their expressions increased gradually with time. α-SA and cTnT expression was significantly higher on day 16 than on day 8 of culture (P<0.01). RT-PCR analysis of the transfected cell showed the presence of GATA-4 expression on day 4 of adherent culture, and the expression increased on days 8 and 12 but decreased on day 16. ANF and α-MHC expressions were found on days 8, 12, and 16, increasing gradually over time and showing significant differences from those on day 4 (P<0.05 or P<0.01). The expression of α-MHC was significantly higher on days 12 and 16 than on day 8 (P<0.05 or P<0.01), and ANF expression was significantly higher on day 16 than on days 8 and 12 (P<0.01). The non-transfected cells were negative for the expressions of all these genes.

CONCLUSIONExogenous expression of Nkx2-5 gene can induce P19 cells to express cardiac markers in vitro.

Actins ; metabolism ; Animals ; Atrial Natriuretic Factor ; metabolism ; Cell Culture Techniques ; Cell Differentiation ; Cell Line ; GATA4 Transcription Factor ; metabolism ; Gene Expression ; Homeobox Protein Nkx-2.5 ; Homeodomain Proteins ; genetics ; metabolism ; Mice ; Myocytes, Cardiac ; cytology ; metabolism ; Myosin Heavy Chains ; metabolism ; Transcription Factors ; genetics ; metabolism ; Transfection ; Troponin T ; metabolism

BACKGROUNDCardiomyocyte transplantation for the therapy of myocardial ischaemia is being paid close attention. However, how the microenvironment controls the differentiation of transplanted bone marrow stromal cells (BMSCs) is unknown. Endothelin-1 (ET-1), a cytokine, increases during myocardial infarction, but it is not known whether ET-1 is responsible for the fate of transplanted BMSCs. In the present study, we investigated the effects of ET-1 on differentiation and maturation of induced rabbit BMSCs, in vitro, to elucidate the cellular biological mechanisms.

METHODSThe proliferation of BMSCs isolated from femur of rabbits was induced by ET-1 only, by 5-azacytidine (5-aza) or ET-1 combined with 5-aza. After 4 weeks of induced culturing, the differentiation rate and the diameter of induced myocyte like cells were estimated and the expressions of GATA-4 protein and phosphorylation level were assayed by Western-blot, RT-PCR analysis of beta-myosin heavy chain (MHC). mRNA expression, levels of troponin-I by immunohistochemical staining and ultrastructure of induce-cultured BMSCs were also determined.

RESULTSBy induction with ET-1 and 5-aza, mean cell diameter of induced BMSCs was larger than induced with 5-aza [(6.26 +/- 0.22) microm cf (5.29 +/- 0.19) microm] (P < 0.001). There was no difference in rate of differentiation of myocyte like cells between the groups induced with 5-aza and ET-1 combined with 5-aza [(29.82 +/- 0.23)% cf (29.94 +/- 0.18)%] (P > 0.05). The expressions of GATA-4 protein and phosphorylation were enhanced significantly in groups induced with ET-1 combined with 5-aza (P < 0.05). In the group induced with ET-1 combined with 5-aza, expression of beta-MHC mRNA was higher than control [(0.122 +/- 0.008) cf (0.022 +/- 0.003)] (P < 0.01), and more troponin-I positive cells were also detected in this group. Differentiated BMSCs showed formations of myofilaments and primitive sarcomere, i.e., morphological characteristics of myocyte like cells.

CONCLUSIONSThis study suggests that induced culturing of BMSCs by ET-1 combined with 5-aza can express cardiomyocytic characteristics whereas ET-1 alone could not induce BMSCs to differentiate to myocyte like cells. ET-1 upregulates the expression of GATA-4 protein and phosphorylation level of induced BMSCs, and rapidly promotes the differentiation and maturation of myocyte like cells from BMSCs.

Animals ; Bone Marrow Cells ; cytology ; ultrastructure ; Cell Differentiation ; drug effects ; Cells, Cultured ; Endothelin-1 ; pharmacology ; GATA4 Transcription Factor ; analysis ; metabolism ; Myocytes, Cardiac ; cytology ; Myosin Heavy Chains ; genetics ; Phosphorylation ; RNA, Messenger ; analysis ; Rabbits ; Stromal Cells ; cytology ; ultrastructure

Nanog, a homeodomain (HD) transcription factor, plays a critical role in the maintenance of embryonic stem (ES) cell self-renewal. Here, we report the identification of an alternatively-spliced variant of nanog. This variant lacked a stretch of amino acids (residues 168-183) located between the HD and tryptophan-repeat (WR) of the previously-reported full length sequence, suggesting that the deleted sequence functions as a linker and possibly affects the flexibility of the C-terminal transactivation domain relative to the DNA binding domain. Expression of mRNA encoding the splice variant, designated as nanog-delta 48, was much lower than that of the full length version in human ES cells. The ratio of nanog-delta 48 transcript to full length transcript increased, however, in multipotent adult progenitor cells. EMSA analysis revealed that both forms of Nanog were able to bind a nanog binding sequence with roughly the same affinity. A reporter plasmid assay also showed that both variants of nanog modestly repressed transactivation of gata-4, whose expression is proposed to be inhibited by nanog, with comparable potency. We conclude that, despite the difference in primary structure and expression pattern in various stem cells, the alternatively-spliced variant of Nanog has similar activity to that of the full length version.
Alternative Splicing/*genetics ; Amino Acid Sequence ; Base Sequence ; Cell Nucleus ; Cells, Cultured ; DNA-Binding Proteins/chemistry/*genetics/metabolism ; Exons/*genetics ; GATA4 Transcription Factor/metabolism ; Gene Expression Profiling ; Genes, Reporter ; Homeodomain Proteins/chemistry/*genetics/metabolism ; Humans ; Introns/genetics ; Molecular Sequence Data ; Promoter Regions (Genetics) ; RNA, Messenger/genetics/metabolism ; Research Support, Non-U.S. Gov't ; Trans-Activation (Genetics) ; Transfection