Smad1/5 signal transduction regulates the ameloblastic differentiation of induced pluripotent stem cells

Abstract Induced pluripotent stem (iPS) cells could be induced into ameloblast-like cells by ameloblasts serum-free conditioned medium (ASF-CM), and bone morphogenetic proteins (BMPs) might be essential during the regulation of this process. The present study investigates the signal transduction that regulates the ameloblastic differentiation of iPS cells induced by ASF-CM. Mouse iPS cells were characterized and then cultured for 14 days in epithelial cell medium (control) or ASF-CM. Bone morphogenetic protein receptor II (BMPR-II) siRNA, inhibitor of Smad1/5 phosphorylation activated by activin receptor-like kinase (ALK) receptors, and inhibitors of mitogen-activated protein kinases (MAPKs) phosphorylation were used to treat the iPS cells in combination with ASF-CM. Real-time PCR, western blotting, and immunofluorescent staining were used to evaluate the expressions of ameloblast markers ameloblastin, enamelin, and cytokeratin-14. BMPR-II gene and protein levels increased markedly in ASF-CM-treated iPS cells compared with the controls, while the mRNA levels of Bmpr-Ia and Bmpr-Ib were similar between the ASF-CM and control groups. ASF-CM stimulation significantly increased the gene and protein expression of ameloblastin, enamelin and cytokeratin-14, and phosphorylated SMAD1/5, p38 MAPK, and ERK1/2 MAPK compared with the controls. Knockdown of BMPR-II and inhibition of Smad1/5 phosphorylation both could significantly reverse the increased expression of ameloblastin, enamelin, and cytokeratin-14 induced by ASF-CM, while neither inhibition of p38 nor ERK1/2 phosphorylation had significant reversing effects. We conclude that smad1/5 signaling transduction, activated by ALK receptors, regulates the ameloblastic differentiation of iPS cells induced by ameloblast-conditioned medium.

Smad1/5 signal transduction regulates the ameloblastic differentiation of induced pluripotent stem cells

Abstract Induced pluripotent stem (iPS) cells could be induced into ameloblast-like cells by ameloblasts serum-free conditioned medium (ASF-CM), and bone morphogenetic proteins (BMPs) might be essential during the regulation of this process. The present study investigates the signal transduction that regulates the ameloblastic differentiation of iPS cells induced by ASF-CM. Mouse iPS cells were characterized and then cultured for 14 days in epithelial cell medium (control) or ASF-CM. Bone morphogenetic protein receptor II (BMPR-II) siRNA, inhibitor of Smad1/5 phosphorylation activated by activin receptor-like kinase (ALK) receptors, and inhibitors of mitogen-activated protein kinases (MAPKs) phosphorylation were used to treat the iPS cells in combination with ASF-CM. Real-time PCR, western blotting, and immunofluorescent staining were used to evaluate the expressions of ameloblast markers ameloblastin, enamelin, and cytokeratin-14. BMPR-II gene and protein levels increased markedly in ASF-CM-treated iPS cells compared with the controls, while the mRNA levels of Bmpr-Ia and Bmpr-Ib were similar between the ASF-CM and control groups. ASF-CM stimulation significantly increased the gene and protein expression of ameloblastin, enamelin and cytokeratin-14, and phosphorylated SMAD1/5, p38 MAPK, and ERK1/2 MAPK compared with the controls. Knockdown of BMPR-II and inhibition of Smad1/5 phosphorylation both could significantly reverse the increased expression of ameloblastin, enamelin, and cytokeratin-14 induced by ASF-CM, while neither inhibition of p38 nor ERK1/2 phosphorylation had significant reversing effects. We conclude that smad1/5 signaling transduction, activated by ALK receptors, regulates the ameloblastic differentiation of iPS cells induced by ameloblast-conditioned medium.

Effect of bushen tiaojing recipe on the expressions of Smad1, Smad5, Smad8, and Smad4 in human mural granulosa cells / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the effect of Bushen Tiaojing Recipe (BTR) on the expressions of drosophila mothers against decapentaplegic protein (Smadl), Smad5, Smad8, and Smad4 on human mural granulosa cells.</p><p><b>METHODS</b>Sixty-six patients undergoing in vitro fertilization-embryo transfer (IVF-ET) were randomly assigned to two groups in the ratio of 1:2, the treatment group and the control group. Twenty-three patients in the treatment group were treated with BTR and GnRHa/FSH/hCG, while forty-three patients in the control group were treated with GnRHa/FSH/hCG. The mRNA expressions of Smad1, Smad5, Smad8, and Smad4 on mural granulosa cells of the mature follicle were detected by real-time PCR on the ovum retrieval day. The expressions of Smad1, Smad5, Smad8, and Smad4 at the protein level were observed using cell immunofluorescence method.</p><p><b>RESULTS</b>The mRNA and protein expressions of Smadl in the granulosa cells were significantly higher in the treatment group than in the control group (P <0.05). There was no statistical difference in the mRNA and protein expressions of Smad5, Smad8, and Smad4 between the two groups.</p><p><b>CONCLUSION</b>The mechanisms of BTR for improving the pregnancy rate and the ovarian functions might be correlated with up-regulating mRNA and protein expressions of Smadl of human mural granulosa cells.</p>

Strontium ranelate promotes osteogenic differentiation of rat bone mesenchymal stem cells through bone morphogenetic protein-2/Smad signaling pathway / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore whether strontium ranelate (Sr) promotes osteoblast lineage differentiation of rat bone mesenchymal stem cells (BMSCs) through the bone morphogenetic protein-2 (BMP-2)/Smad signaling pathway.</p><p><b>METHODS</b>Cultured rat BMSCs were exposed to different concentrations of Sr, noggin (an inhibitor of BMP-2) or Smad1 siRNA. The activity of alkaline phosphatase (ALP) in the exposed cells was detected by colorimetry, and the formation of mineralized nodules was observed with alizarin red staining. The expressions of phosphorylated (p) Smad1/5/8 and Runt-related transcription factor 2 (Runx2) in the cells were detected by Western blotting.</p><p><b>RESULTS</b>Exposure to Sr at 0.1 to 10 mmol/L for 1 h markedly increased the expression of p-Smad1/5/8 in the BMSCs, and the increment was the most obvious following 1 mmol/L Sr exposure. Preconditioning with 100 ng/ml noggin for 2 h inhibited Sr-induced up-regulation of p-Smad1/5/8 expressions. Exposure of the cells to 0.1 to 5 mmol/L Sr for 6 h significantly enhanced Runx2 expression, and the peak enhancement occurred following 1 mmol/L Sr exposure. Transfection of the BMSCs with Smad1 siRNA decreased the basal level of Smad1/5/8 protein expression, and also inhibited Sr-induced up-regulation of p-Smad1/5/8 and Runx2 expressions as well as Sr-induced enhancement of ALP activity and formation of mineralized nodules.</p><p><b>CONCLUSION</b>The BMP-2/Smad pathway is involved in Sr-induced osteoblast differentiation of rat BMSCs.</p>

Toxicarioside A, isolated from tropical Antiaris toxicaria, blocks endoglin/TGF-β signaling in a bone marrow stromal cell line

OBJECTIVE@#To investigate possible mechanism of toxicarioside A in HS-5 bone stromal cells.@*METHODS@#HS-5 bone stromal cells were cultured in media supplemented with various concentrations of toxicarioside A or control DMSO (not treatment). Endoglin and TGF-β were detected by Northern and Western blot analysis and quantified in a standard method. Downstream molecules of endoglin and TGF-β (Smad1, Smad2 and their active phosphorylated counterparts, pSmad1 and pSmad2) were also detected and quantified by Western blot analysis. In addition, cell proliferation assay and small interfering RNA (siRNA) against endoglin were used to certificate the function of endolgin in the HS-5 cells.@*RESULTS@#Compared with the not treated (0 μg/mL) or DMSO treated control HS-5 cells, HS-5 cells treated with toxicarioside A were found significant attenuation of endolgin and TGF-β expression. Significant inhibition of cell proliferation was also found in the HS-5 cells treated with toxicarioside A. ALK1-related Smad1 and ALK5-related Smad2 were decreased in HS-5 cells treated with toxicarioside A. In addition, phosphorylated Smad1 (pSmad1) and Smad2 (pSmad2) were also found attenuation in toxicarioside A-treated HS-5 cells. RNA interference showed that blockage of endoglin by siRNA also decreased Smad1 and Smad2 expression in HS-5 cells.@*CONCLUSIONS@#Our results indicate that toxicarioside A can influence bone marrow stromal HS-5's function and inhibit HS-5 cell proliferation by alteration of endoglin-related ALK1 (Smad1) and ALK5 (Smad2) signaling.

Effects of antenatal administration of dexamethasone and betamethasone on signal transduction of bone morphogenetic protein in the fetal lungs of rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the role of antenatal glucocorticoid (dexamethasone and betamethasone) on bone morphogenetic protein (BMP) signal transduction of the rat fetal lungs.</p><p><b>METHODS</b>Fifteen pregnant rats were randomly divided into five groups: the rats treated with dexamethasone for 1 day (1D-DEX) or 3 days (3D-DEX), with betamethasone for 1 day (1D-BEX) or 3 days (3D-BEX) or with normal saline (control group), followed cesarean section on the 19th day of gestation. The mRNA levels of BMP4, BMPR-II, Smad1 and ATF-2 of fetal rat lungs were ascertained by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of BMP4, BMPR-II, Smad1 and ATF-2 antigen expression in fetal lungs was assessed by immune histochemical staining. The expression of BMP4 and BMPR-II was determined by Western blot.</p><p><b>RESULTS</b>The levels of BMP4, BMPR-II and Smad1 mRNA expression were up-regulated in the 1D-BEX, 3D-BEX and 3D-DEX groups compared with those in the control group (P<0.05). The immune histochemiscal analysis showed that the expression of BMP4, BMPR-II, Phospho-Smad1 (pSmad1) and ATF-2 in the 1D-BEX, 3D-BEX and 3D-DEX groups was significantly higher than that in the control group (P<0.01). The results of Western blot demonstrated that the expression of BMP4 and BMPR-II protein increased significantly in the 1D-BEX, 3D-BEX and 3D-DEX groups when compared with the control group (P<0.01).</p><p><b>CONCLUSIONS</b>Betamethasone and dexamethasone may play important roles in the regulation of BMP signal transduction in the rat fetal lungs. Up-regulation of BMP4, BMPR-II and Smad1 might be one of crucial factors for the glucocorticoid-induced maturity of fetal lungs.</p>

Expression of Smad1 and Smad5 in the testis of infertile rats with kidney-yang deficiency / 中华男科学杂志

<p><b>OBJECTIVES</b>To study the expression of Smad1 and Smad5 in the testis of infertile rats with adenine-modeled kidney-yang deficiency and the pathological mechanism of infertility with kidney-yang deficiency, attempting to obtain experimental evidence for the prevention and treatment of male infertility.</p><p><b>METHODS</b>Forty-eight 60 d male SD rats were divided randomly into 6 groups with 8 in each: 7 d, 14 d and 21 d kidney-yang deficiency groups, and 7 d, 14 d and 21 d control groups. The experimental rats had been fed with adenine (300 mg/kg) and the expression levels of Smad1 and Smad5 were measured with immunohistochemical SABC method at the 7th, 14th and 21st day.</p><p><b>RESULTS</b>Smad1 immunoreactivity was mainly located in the spermatogonia, spermatocytes and spermatids, and the reactive substance distributed in cytoplasm with negative nuclei. Sertoli cells and Leydig cells were negative. Compared with the control, the expression level of Smad1 was decreased significantly at the 21st day (P < 0.05), but with no significant difference at the 7th and 14th day (P > 0.05). Smad5 immunoreactivity was mainly located in the spermatogonia and spermatocytes, and the reactive substance distributed in cytoplasm with negative nuclei. Compared with the control, the expression level of Smad5 was not significantly different at the 7th day (P > 0.05). The expression of Smad5 was negative at the 14th and the 21st day.</p><p><b>CONCLUSION</b>The weaker expression of Smad1 and no expression of Smad5 may be one of the pathological mechanisms of infertility with adenine-modeled kidney-yang deficiency.</p>

Expression and localization of Smad1, Smad2 and Smad4 proteins in rat testis during postnatal development / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To study the expression and regulation of Smad1, Smad2 and Smad4 proteins (intracellular signaling molecules of transforming growth factor-b family) in rat testis during postnatal development.</p><p><b>METHODS</b>The whole testes were collected from SD rats aged 3, 7, 14, 28 and 90 (adult) days. The cellular localization and developmental changes were examined by immunohistochemistry ABC method with the glucose oxidase-DAB-nickel enhancement technique. Quantitative analysis of the immunostaining was made by the image analysis system. The Smads proteins coexistence in the adult rat testis was tested by the double immune staining for CD14-Smad4 and Smad2-Smad4. The protein expression of Smad during rat testicular development was examined by means of Western blots.</p><p><b>RESULTS</b>Smad1, Smad2 and Smad4 were present throughout testicular development. The immunostaining of Smad1 and Smad2 were present in spermatogenic cells. A positive immunoreactivity was located at the cytoplasm, but the nucleus was negative. Smad1 was immunolocalized at the d14, d28 and adult testes, while Smad2, at the d7, d14, d28 and adult testis. There was positive immunoreaction in the Sertoli cells and Leydig cells as well. The immunolocalization of Smad4 was exclusively at the cytoplasm of Leydig cells and the nuclei were negative throughout the testicular development. No expression was detected in the germ cells. The results of image and statistical analysis showed that generally the expression of Smad1, Smad2 and Smad4 in the testis tended to increase gradually with the growth of the rat.</p><p><b>CONCLUSION</b>The present data provide direct evidences for the molecular mechanism of TGF-bgr action in rat testes during postnatal development and spermatogenesis.</p>