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.

Effects of casein kinase 2 interacting protein-1 on the osteogenic differentiation ability of human periodontal ligament stem cells / 口腔疾病防治

Objective @#To investigate the effects of casein kinase 2 interacting protein-1 (CKIP-1) on the osteogenic differentiation ability of human periodontal ligament stem cells (hPDLSCs).@*Methods @#The hPDLSCs were obtained by primary culture with periodontal ligament tissues that were collected from normal humans. Then, a lentiviral vector containing a CKIP-1-specific siRNA sequence was constructed, and the transcriptional level of CKIP-1 in hPDLSCs was downregulated after vector infection. The P4 cells were divided into four groups: the control group, negative control group (infected with a control vector), CKIP-siRNA group (infected by a CKIP-1 siRNA lentivirus) and CKIP-1 group (infected by a CKIP-1 overexpression virus). All of the cells were cultured under osteogenic induction for 21 days. Then, alizarin red staining and quantitative determination were performed to detect the osteogenic differentiation ability of the hPDLSCs. In addition, qPCR was used to detect the transcriptional level of osteogenesis-related regulatory factors, such as Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteocalcin (OCN), and receptor activator of nuclear factor kappa-B ligand (RANKL), and the osteogenesis-related regulatory factors of the bone morphogenetic protein (BMP) signaling pathway.@*Results@#There were no differences in the indexes between the negative control group and the control group (P > 0.05). Compared with the negative control group, the CKIP-siRNA group demonstrated more mineralized nodules (P < 0.05), significantly increased calcium salt deposition (P < 0.05), and increased mRNA levels of osteogenesis-related regulatory factors, such as Runx2 , ALP, OCN, and RANKL, and the osteogenesis-related regulatory factors of BMP signaling pathway (P < 0.05). @*Conclusion@#Downregulation of CKIP-1 could promote the osteogenic differentiation of hPDLSCs, which is related to the transcription level of osteogenic-related regulatory factors.

Memory-improving Substances Basis and Mechanism of Polygalae Radix, Acori Tatarinowii Rhizoma and Its Couplet Medicines / 中国实验方剂学杂志

Polygalae Radix and Acori Tatarinowii Rhizoma were first recorded in Shennong's Herbal Classic. Both of them can "improve people's memory". Long-term administration can make body light and macrobian. They have often been used as couplet medicines and the core combination of nootropic and memory improvement prescriptions. At present, traditional Chinese medicine clinicians believes that the principle of Polygalae Radix and Acori Tatarinowii Rhizoma in improving memory or intelligence is to supplement the deficiency, remove phlegm and unblock nine orifices, with sufficient evidences for the traditional theory. However, its material basis and mechanism for improving memory have not been fully elucidated. In this paper, we searched the literatures about pharmacological and pharmacodynamics mechanism of Polygalae Radix,Acori Tatarinowii Rhizoma and their chemical components on nervous system in recent ten years from Pubmed database and CNKI. The main material basis for improving memory of Polygalae Radix-saponins, oligosaccharides and alone, the main material basis for improving memory of Acori Tatarinowii Rhizoma-α-asarone,β-asarone and eugenol, the changes of the quality and quantity of the active substances after combination, and the mechanism of improving memory of the single drugs and their couplet medicines, such as scavenging free radicals, regulating cholinergic system, clearing β-amyloid protein(Aβ), decreasing the level of phosphorylation of Tau protein, improving the rate of apoptosis and regulating synaptic plasticity, were systematically collected, analyzed and summarized. In view of the current research situation, this paper points out the possible shortcomings, with the aim to further explore the mechanism of Polygalae Radix combined with Acori Tatarinowii Rhizoma with the mechanism of "1+1>2".

Simultaneous determination of four constituents in Liujing Toutong Tablets by HPLC / 中成药

AIM To establish an HPLC method for the simultaneous content determination of four constituents in Liujing Toutong Tablets (Angelicae dahuricae Radix,Magnoliae Flos,Ligustici Rhizoma et Radix,etc.).METHODS The analysis of 30％ ethanol extract of this drug was performed on a 35 ℃ thermostatic Waters C18 column (4.6 mm × 250 mm,5 μm),with the mobile phase comprising of methanol-4％ acetic acid flowing at 1.0 mL/min in a gradient elution manner,and the detection wavelength was set at 320 nm.RESULTS Puerarin,ferulic acid,imperatorin and isoimperatorin showed good linear relationships within the ranges of 60.6-303 μg/mL (r=0.999 9),1.59-7.95 μg/mL (r =0.999 9),1.57-7.85 μg/mL (r =0.999 9) and 0.752 5-3.762 5 μg/mL (r =0.999 7),whose average recoveries (RSDs) were 97.75％ (1.7％),97.68％ (2.3％),97.94％ (1.0％) and 98.29％ (1.6％),respectively.CONCLUSION This stable and reliable method can be used for the quality control of Liujing Toutong Tablets.

Mechanism of PC12 cell differentiation induced by total salvianolic acid / 中国药理学与毒理学杂志

OBJECTIVE To study the differentiation of PC12 cells induced by total salvianolic acid (Tsa) and the mechanism. METHODS MTT assay was used to detect the effect of Tsa 0.01, 0.1 and 1.0 μg·L-1on proliferation of PC12 cells and on the cells damaged by oxygen and glucose deprivation (OGD).The number of projections of PC12 cells was statistically analyzed.Western blotting was applied to detect the levels of microtubule-associated protein2 (MAP-2), extracellular signal-regulated kinase1/2 (ERK1/2), phosphorylated ERK1/2(p-ERK1/2), mitogen-activated protein kinase kinase1/2(MEK1/2) and p-MEK1/2 proteins.MEK inhibitor U0126 was examined for its effect on expressions of p-ERK1/2 and ERK1/2 protein in PC12 cells induced by Tsa 1.0 μg·L-1.RESULTS Compared with normal control group, Tsa 1.0 μg·L-1could promote PC12 cell proliferation, and the survival rate was increased by 90%, but the survival rate of PC12 cells was not affected by Tsa 0.01 or 0.1 μg·L-1. Compared with OGD injured group,PC12 cells injured by OGD could be repaired by Tsa 0.1 or 1.0 μg·L-1,and the survival rate was increased to (47.7±1.8)% and (63.2±13.0)%, respectively (P<0.05, P<0.01). Compared with normal control group,Tsa 0.01,0.1 and 1.0 μg·L-1could promote the growth of PC12 cell projections (P<0.01). Western blotting results showed that Tsa could promote the expressions of MAP-2, p-ERK1/2 and p-MEK1/2 proteins, and this effect could be blocked by U0126 inhibitor (P<0.01). CONCLUSION Tsa can induce the proliferation and differentiation of PC12 cells, the mechanism of which is possibly the activation of p-MEK and p-ERK1/2.

Effect of oxidative stress on periprosthetic osteolysis induced by TCP wear particles in mouse calvaria and its mechanism / 中国应用生理学杂志

OBJECTIVE@#To explore the effect of oxidative stress on periprosthetic osteolysis induced by TCP wear particles in mouse calvaria and its mechanism.@*METHODS@#Thirty-six male ICR mice were randomly divided into three groups (=12):sham group, TCP wear particles (TCP) group and N-acetyl-L-cysteine (NAC) group. Aperiprosthetic osteolysis model in mouse was established by implanting 30 mg of TCP wear particles onto the surface of bilateral parietal bones following removal of the periosteum. On the 2nd day post-operation, NAC (1.0 mg/kg) was locally injected to the calvarium under the periosteum every other day for 2 weeks. Then, all the mice were sacrificed to obtain blood and the calvaria. Periprosthetic osteolysis in the mouse calvaria was observed by tartrate resistant acid phosphatase (TRAP) staining; serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), interleukin-6 (IL-6); total anti-oxidation capacity (T-AOC) and superoxide dismutase (SOD) activity were examined by ELISA and chemical colorimetry, respectively; protein levels of glucose-regulated protein 78 (GRP78), protein kinase R-like ER kinase (PERK), phospho-PERK (p-PERK), eukaryotic initiation factor 2α (eIF2α) and phospho-eIF2α (p-eIF2α) in periprosthetic bone tissue were detected by Western blot.@*RESULTS@#Compared with sham group, serum levels of TNF-α, IL-1β and IL-6, and osteolysis area were increased obviously in TCP group (<0.05), and serum level of T-AOC and SOD activity were decreased significantly in TCP group (<0.05), GRP78 expression, the ratio of p-PERK and PERK, p-eIF2α and eIF2α in the mouse calvaria of TCP group were up-regulated markedly. Compared with TCP group, serum levels of TNF-α, IL-1β and IL-6, and osteolysis area were decreased markedly in NAC group (<0.05), serum level of T-AOC and SOD activity were increased obviously in NAC group (<0.05), and GRP78 expression, the ratio of p-PERK/PERK and p-eIF2α/eIF2α were obviously down-regulated.@*CONCLUSIONS@#Inhibition of oxidative stress can prevent periprosthetic osteolysis induced by TCP wear particles, which may be mediated by inactivation of PERK/eIF2α signaling pathway.

Annual point-prevalence of healthcare-associated infection surveys in a university hospital in China, 2007-2011

Successive point-prevalence surveys were conducted annually from 2007 to 2011 to monitor the prevalence of healthcare-associated infections [HAIs] in a university hospital in Hubei Province in China. The surveys used the case definition criteria established by the Ministry of Health of the People's Republic of China. In the 5 surveys, the overall frequency of HAIs was 3.16% [301/9533]. No significant differences were identified in the point prevalence measurements of HAIs in any of the years from 2007 to 2011. Of all the cases, proportionally, the most frequent infection site was the respiratory tract [2.34%], followed by surgical sites [0.43%] and urinary tract sites [0.28%]. Gram-negative aerobic bacilli were the most common organisms mentioned; the most frequently isolated organism was Pseudomonas aeruginosa, followed by Escherichia coliand Acinetobacter baumannii. Approximately one-half of the patients were receiving antibiotics at the time of the surveys. Cephalosporin, penicillin, and quinolone were most commonly used for treatment or prevention. The differences found in HAI prevalence data across the 5 surveys given in the hospital were not statistically significant. In conclusion, this successive point-prevalence survey provides information about the trend of HAI prevalence, epidemical character, and the use of antibiotics among the university hospital's in-patients. This information allows us to initiate targeted programs for infection prevention and control