Endometrial receptivity and implantation require uterine BMP signaling through an ACVR2A-SMAD1/SMAD5 axis.

During early pregnancy in the mouse, nidatory estrogen (E2) stimulates endometrial receptivity by activating a network of signaling pathways that is not yet fully characterized. Here, we report that bone morphogenetic proteins (BMPs) control endometrial receptivity via a conserved activin receptor type 2 A (ACVR2A) and SMAD1/5 signaling pathway. Mice were generated to contain single or double conditional deletion of SMAD1/5 and ACVR2A/ACVR2B receptors using progesterone receptor (PR)-cre. Female mice with SMAD1/5 deletion display endometrial defects that result in the development of cystic endometrial glands, a hyperproliferative endometrial epithelium during the window of implantation, and impaired apicobasal transformation that prevents embryo implantation and leads to infertility. Analysis of Acvr2a-PRcre and Acvr2b-PRcre pregnant mice determined that BMP signaling occurs via ACVR2A and that ACVR2B is dispensable during embryo implantation. Therefore, BMPs signal through a conserved endometrial ACVR2A/SMAD1/5 pathway that promotes endometrial receptivity during embryo implantation.

Effect of astragaloside IV on cognitive dysfunction in rats with cerebrally infarcted via TGF-ß / Smad signaling pathway.

Cerebral infarction is an acute cerebrovascular disease caused by abnormal blood circulation in the brain. In the present study, we investigate the effect of astragaloside IV on cognitive dysfunction in cerebrally infarcted rats via transforming growth factor-ß (TGF-ß) / Smad signaling pathway. For this purpose, 45 rats were divided into three groups including astragaloside, model, and control. 30 of 45 healthy adult male SD rats were randomly selected to establish an acute cerebral infarction model. 15 modeled rats were enrolled as a model and astragaloside group, and another 15 rats as a blank control group. The rats in the astragaloside group were fed with astragaloside IV according to 1.08 g/kg body weight, and those in the blank group and model group were given matching normal saline. The levels of TGF-ß, Smad1, Smad3 and Smad7 of TGF-ß/Smad signaling transduction pathway at T0 (week 0), T1 (week 3) and T2 (week 6) were determined by enzyme-linked immunosorbent assay (ELISA). The modified neurological severity score (mNSS) was used to evaluate the improvement of cognitive dysfunction in rats. The mNSS of rats with cerebral infarction in the astragaloside group was lower than that in the control group and model group (P< 0.05). While the levels of TGF-ß, Smad1, Smad3 and Smad7 in the astragaloside group were higher than those in the control group and model group (P< 0.05). Astragaloside IV plays an important role in improving cognitive dysfunction in rats with cerebral infarction while affecting the levels of TGF-ß, Smad1, Smad3 and Smad7 and activating TGF-ß / Smad signaling pathway.

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

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.

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.

Harmine promotes molar root development via SMAD1/5/8 phosphorylation.

Tooth and bone are major tissues involved in physiological calcification in the body, and they use similar molecular pathways for development, homeostasis, and regeneration. Harmine (HMN) is a natural small compound that stimulates osteoblast differentiation in vitro and in vivo. Here we examined the biological effect of HMN on the postnatal development of molar tooth roots and periodontal tissues. HMN supported the formation of tooth roots and periodontal tissues in developing tooth germs. In tooth germ organ culture, HMN promoted the elongation of Hertwig's epithelial root sheath (HERS) and stimulated cell proliferation in HERS and dental follicle-derived tissues, including dental papillae and dental follicles. HMN stimulated cell proliferation and cell movement of HERS-derived cells without mesenchymal cells in vitro and directly induced the phosphorylation of SMAD1/5/8 protein in HERS-derived cells. Our results indicated that HMN was the first natural small compound to stimulate postnatal development of tooth germs.

Potential differentiation ability of gingiva originated human mesenchymal stem cell in the presence of tacrolimus.

The aim of the present study is to evaluate the potential differentiation ability of gingiva originated human mesenchymal stem cell in the presence of tacrolimus. Tacrolimus-loaded poly(lactic-co-glycolic acid) microspheres were prepared using electrospraying technique. In vitro release study of tacrolimus-loaded poly(lactic-co-glycolic acid) microspheres was performed in phosphate-buffered saline (pH 7.4). Gingiva-derived stem cells were isolated and incubated with tacrolimus or tacrolimus-loaded microspheres. Release study of the microspheres revealed prolonged release profiles of tacrolimus without any significant initial burst release. The microsphere itself did not affect the morphology of the mesenchymal stem cells, and cell morphology was retained after incubation with microspheres loaded with tacrolimus at 1 µg/mL to 10 µg/mL. Cultures grown in the presence of microspheres loaded with tacrolimus at 1 µg/mL showed the highest mineralization. Alkaline phosphatase activity increased with an increase in incubation time. The highest expression of pSmad1/5 was achieved in the group receiving tacrolimus 0.1 µg/mL every third day, and the highest expression of osteocalcin was achieved in the group receiving 1 µg/mL every third day. Biodegradable poly(lactic-co-glycolic acid)-based microspheres loaded with tacrolimus promoted mineralization. Microspheres loaded with tacrolimus may be applied for increased osteoblastic differentiation.

Excess BMP Signaling in Heterotopic Cartilage Forming in Prg4-null TMJ Discs.

Heterotopic cartilage develops in certain pathologic conditions, including those affecting the human temporomandibular joint (TMJ), but the underlying molecular mechanisms remain obscure. This is in part due to the fact that a reliable animal model of such TMJ diseases is not available. Here, we show that aberrant chondrocyte differentiation and ectopic cartilage formation occur spontaneously in proteoglycan 4 (Prg4) mutant TMJ discs without further invasive procedure. By 2 mo of age, mutant disc cells displayed chondrocyte transdifferentiation, accompanied by strong expression of cartilage master gene Sox9 and matrix genes aggrecan and type II collagen. By 6 mo, heterotopic cartilage had formed in the discs and expressed cartilage hypertrophic markers Runx2 and ColX. The ectopic tissue grew in size over time and exhibited regional mineralization by 12 mo. Bone morphogenetic protein (BMP) signaling was activated with the ectopic chondrogenic cells and chondrocytes, as indicated by phosphorylated Smad 1/5/8 nuclear staining and by elevated expression of Bmp2, Bmpr1b, Bmpr2, and BMP signaling target genes. Likewise, we found that upon treatment with recombinant human BMP 2 in high-density micromass culture, mutant disc cells differentiated into chondrocytes and synthesized cartilage matrix more robustly than control cells. Importantly, a specific kinase inhibitor of BMP receptors drastically attenuated chondrogenesis in recombinant human BMP 2-treated mutant disc cultures. Unexpectedly, we found that Prg4 was expressed at joint-associated sites, including disc/muscle insertion and muscle/bone interface, and all these structures were abnormal in Prg4 mutants. Our data indicate that Prg4 is needed for TMJ disc integrity and function and that its absence leads to ectopic chondrogenesis and cartilage formation in conjunction with abnormal BMP signaling. Our findings imply that the BMP signaling pathway could be a potential therapeutic target for prevention or inhibition of ectopic cartilage formation in TMJ disease.

The Effect of Tumor Necrosis Factor-α at Different Concentrations on Osteogenetic Differentiation of Bone Marrow Mesenchymal Stem Cells.

Tumor necrosis factor-alpha (TNF-α) has been demonstrated to have a close relationship with inflammation in the body. Although most researchers confirmed that TNF-α can have an effect on the expression of osteoblast specific genes, they had not elucidated the regulation of inflammatory factors in osteogenic gene expression during the process of bone marrow mesenchymal stem cells (BMMSCs) differentiating to osteoblast. The aim of this study was to investigate the effect of TNF-α at different concentrations on osteogenetic differentiation of BMMSCs. In this study, BMMSCs proliferation was analyzed by using cell counting kit-8 assay, cell osteogenic differentiation was evaluated by means of alkaline phosphatase activity assay and Von Koaas staining and the messenger RNA (mRNA) expression of bone morphogenetic proteins-2 (BMP-2) and drosophila mothers against decapentaplegic protein 1 (Smad1) was measured through real-time polymerase chain reaction. The results indicated that a low concentration of TNF-α at short-term promotes the osteogenetic differentiation of BMMSCs and increases the mRNA expression of BMP-2 and Smad1, but inhibits the osteogenetic differentiation of BMMSCs and the expression of BMP-2 and Smad1 at long term. In addition, regardless of a short or long time, a high concentration of TNF-α inhibits the osteogenetic differentiation of BMMSCs and the expression of Smad1, but results in a high expression of BMP-2.

Effects of glutamine on proliferation, migration, and differentiation of human dental pulp cells.

INTRODUCTION: Although glutamine (Gln) is mitogenic in various cell types, little is known about its role in human dental pulp cells (HDPCs). This study investigated the effects of Gln on proliferation, migration, and odontoblastic differentiation of HDPCs and the underlying signal pathway mechanisms. METHODS: Growth and migration were assessed by cell counting and colorimetric cell migration kits. Differentiation was measured as alkaline phosphatase activity, calcified nodule formation by alizarin red staining, and marker mRNA expression by reverse transcriptase-polymerase chain reaction (RT-PCR). Chemokine expression was also evaluated by RT-PCR. Signal transduction pathways were examined by RT-PCR and Western blot analysis. RESULTS: Gln dose-dependently increased proliferation, migration, alkaline phosphatase activity, mineralized nodule formation, and odontoblast-marker mRNA of HDPCs. Gln also up-regulated expression of interleukin-6, interleukin-8, MCP-1, MIP-3α, CCL2, CCL20, and CXCL1. Gln increased BMP-2 and BMP-4 mRNA, phosphorylation of Smad 1/5/8, ß-catenin, and key proteins of the Wnt signaling pathway. Furthermore, Gln resulted in up-regulation of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase. In addition, noggin, DKK1, inhibitors of p38, ERK, and JNK significantly attenuatted Gln-induced growth, migration, and odontoblastic differentiation. CONCLUSIONS: Collectively, this study demonstrated that Gln promoted growth, migration, and differentiation in HDPCs through the BMP-2, Wnt, and MAPK pathways, leading to improved pulp repair and regeneration.

Enamel matrix derivative: protein components and osteoinductive properties.

BACKGROUND: Although enamel matrix derivative (EMD) has demonstrated the ability to promote angiogenesis and osteogenesis both in vitro and in vivo, the specific elements within the EMD compound responsible for these effects remain unknown. METHODS: Nine different protein pools from a commercially produced EMD were collected based on molecular weight. Six of these pools, along with the complete EMD unfractionated compound and positive and negative controls, were tested for their ability to induce bone formation in a calvarial induction assay. Immunocytochemistry of phosphorylated SMAD1/5/8 (phospho-SMAD), osterix, and vascular endothelial growth factor A (VEGF-A) was carried out at selected time points. Finally, proteomic analysis was completed to determine the specific protein-peptide content of the various osteoinductive pools. RESULTS: One of the lower-molecular-weight pools tested, pool 7, showed bone induction responses significantly greater than those of the other pools and the complete EMD compound and was concentration dependent. Dynamic bone formation rate analysis demonstrated that pool 7 was optimally active at the 5- to 10-µg concentration. It was demonstrated that EMD and pool 7 induced phospho-SMAD, osterix, and VEGF-A, which is indicative of increased bone morphogenetic protein (BMP) signaling. Proteomic composition analysis demonstrated that pool 7 had the highest concentration of the biologically active amelogenin-leucine-rich amelogenin peptide and ameloblastin 17-kDa peptides. CONCLUSIONS: These studies demonstrate that the low-molecular-weight protein pools (7 to 17 kDa) within EMD have greater osteoinductive potential than the commercially available complete EMD compound and that the mechanism of action, in part, is through increased BMP signaling and increased osterix and VEGF-A. With this information, selected components of EMD can now be formulated for optimal osteo- and angio-genesis.

TGF-ß1, Smad-2/-3, Smad-1/-5/-8, and Smad-4 signaling factors are expressed in ameloblastomas, adenomatoid odontogenic tumors, and calcifying cystic odontogenic tumors: an immunohistochemical study.

OBJECTIVES: The TGF-ß/Smad signaling pathway regulates diverse cellular functions, including tooth development, and is involved in numerous pathological processes such as tumorigenesis. The aim of this study was to investigate the immunoexpression of the TGF-ß/Smad signaling pathway members in ameloblastoma (AM), calcifying cystic odontogenic tumor (CCOT), and adenomatoid odontogenic tumor (AOT). MATERIALS AND METHODS: This retrospective cross-sectional study included 65 tissue specimens: 34 AMs, 13 CCOTs, and 18 AOTs. Serial sections were immunohistochemically stained with TGF-ß1, Smad-4, Smad-1/-5/-8, and Smad-2/-3 antibodies, and a semiquantitative measurement of the positive cells was carried out by two oral pathologists using a 0-3 scale (0: no immunoreactivity, 1: <20% positive cells, 2: 20-50% positive cells, 3: >50% positive cells). RESULTS: All biomarkers studied were found significantly decreased in AM compared to CCOT and AOT. AOT and CCOT expressed Smad-1/-5/-8 more strongly compared to AM (OR = 11.66, P < 0.001 and OR = 5.34, P = 0.013, respectively), and Smad-2/-3 immunostaining was found significantly increased in CCOT (OR = 10.42, P = 0.001) and AOT (OR = 5.16, P < 0.004) compared to AM. Similarly, Smad-4 was expressed more strongly in AOT and CCOT compared to AM (P = 0.001), while AOT demonstrated a fivefold higher chance to express TGF-ß1 compared to AM (P = 0.011). CONCLUSION: TGF-ß/Smad signaling pathway is activated in AM, AOT, and CCOT. The statistically significant reduced TGF-ß1/Smad immunoexpression in AM compared to AOT/CCOT could be associated with the more aggressive biological behavior of AM including increased cell proliferation and reduced apoptosis and differentiation. Thus, the biomarkers TGF-ß, Smad-4, Smad-1/-5/-8, and Smad-2/-3 could serve as supplementary diagnostic indices between odontogenic tumors of high and low neoplastic dynamics.

[Recent progress in understanding the molecular pathogenesis of diabetic nephropathy].

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease and a major contributor to morbidity and mortality of diabetic patients throughout the world. Albuminuria is one of the most characteristic functional changes in the early phase of DN. However, many recent studies have shown that there was no clear association between glomerulosclerosis and albuminuria in type 1 and 2 diabetes. DN is a progressive kidney disease caused by angiopathy of capillaries in the kidney glomeruli and is morphologically characterized by progressive expansion of mesangial matrix and thickening of the glomerular basement membrane. Type IV collagen (Col4) is a major component of the extracellular matrix (ECM) in the expanded mesangial matrix. Advanced glycation endproducts (AGEs) produced as the result of hyperglycemia are known to stimulate the production of ECM proteins in mesangial cells, resulting in glomerulosclerosis. Using a yeast one-hybrid screening, Smad1 was identified as a transcriptional regulator of Col4 in AGE-treated mesangial cells. Smad1 also regulated other ECM proteins, such as type I collagen and osteopontin, as well as alpha smooth muscle actin. Moreover, there was a very good correlation between urinary Smad1 levels and the development of mesangial expansion, whereas the correlation between albuminuria and mesangial expansion was not significant in experimental DN models. In addition, urinary Smad1 was revealed to be a good predictor for later onset of morphological changes and to be used to monitor the effect of ARB in DN. In conclusion, urinary Smad1 is expected to be a useful diagnostic biomarker for DN.

[Effects of antenatal administration of dexamethasone and betamethasone on signal transduction of bone morphogenetic protein in the fetal lungs of rats].

OBJECTIVE: To study the role of antenatal glucocorticoid (dexamethasone and betamethasone) on bone morphogenetic protein (BMP) signal transduction of the rat fetal lungs. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Estrogens attenuate oxidative stress and the differentiation and apoptosis of osteoblasts by DNA-binding-independent actions of the ERalpha.

Estrogens diminish oxidative stress in bone and bone marrow, attenuate the generation of osteoblasts, and decrease the prevalence of mature osteoblast apoptosis. We have searched for the molecular mechanism of these effects using as tools a mouse model bearing an estrogen receptor alpha (ERalpha) knock-in mutation that prevents binding to DNA (ERalpha(NERKI/-)) and several osteoblast progenitor cell models expressing the wild-type ERalpha or the ERalpha(NERKI/-). We report that the ability of estrogens to diminish the generation of reactive oxygen species, stimulate the activity of glutathione reductase, and decrease the phosphorylation of p66(shc), as well as osteoblastogenesis and osteoblast number and apoptosis, were fully preserved in ERalpha(NERKI/-) mice, indicating that the DNA-binding function of the ERalpha is dispensable for all these effects. Consistent with the attenuation of osteoblastogenesis in this animal model, 17beta-estradiol attenuated bone morphogenetic protein 2 (BMP-2)-induced gene transcription and osteoblast commitment and differentiation in murine and human osteoblastic cell lines. Moreover, 17beta-estradiol attenuated BMP-2-induced differentiation of primary cultures of calvaria- or bone marrow-derived osteoblastic cells from ERalpha(NERKI/-) mice as effectively as in cells from wild-type littermates. The inhibitory effect of the hormone on BMP-2 signaling resulted from an ERalpha-mediated activation of ERKs and the phosphorylation of Smad1 at the linker region of the protein, which leads to proteasomal degradation. These results illustrate that the effects of estrogens on oxidative stress and the birth and death of osteoblasts do not require the binding of ERalpha to DNA response elements, but instead they result from the activation of cytoplasmic kinases.

Daily low-intensity pulsed ultrasound stimulates production of bone morphogenetic protein in ROS 17/2.8 cells.

Although daily low-intensity pulsed ultrasound (LIPUS) can accelerate osteogenic differentiation of the rat clonal cell line ROS 17/2.8, the molecular mechanism that underlies this phenomenon is unclear. The purpose of this study was to determine which molecules exposed to daily LIPUS treatment stimulate osteogenic differentiation. The cells were cultured in the presence and absence (control) of LIPUS stimulation. LIPUS treatments consisted of 1.5-MHz ultrasound administered at an intensity of 30 mW/cm(2), 20 min daily for 7 days. The expression of bone morphogenetic proteins (BMPs) and their receptors involved in osteogenesis were measured using real-time PCR and/or Western blot analysis. Phosphorylation of the mothers against decapentaplegic 1 (Smad1) protein was determined by Western blotting. Daily LIPUS treatment significantly increased the expression of BMP-2, -4, and -7 and their receptors, and also phosphorylation of Smad1. Noggin markedly inhibited the daily LIPUS-induced phosphorylation of Smad1. Our findings demonstrate that the osteogenic activity of daily LIPUS may be mediated by BMPs in ROS 17/2.8 cells.

Detection, identification and in vivo treatment responsiveness of bone morphogenetic protein (BMP)-activated cell populations in the synovium of patients with rheumatoid arthritis.

OBJECTIVE: To characterise the bone morphogenetic protein (BMP) target cells positive for phosphorylated (P)-SMAD1/5, in rheumatoid arthritis (RA) synovium. METHODS: Synovial biopsies were obtained by needle arthroscopy. Anti-P-SMAD1/5 antibodies were used for Western blot (WB) on protein extracts from RA and normal synovium and for immunostaining of synovial biopsy sections. Positive cells were further identified by double staining for CD3, CD20, CD68, CD138, CD90, alpha smooth muscle actin (SMA), endoglin (CD105) and von Willebrand factor (VWF). In sections from early patients with RA taken before and under antirheumatic treatment, the degree of inflammation and activation of the BMP pathway were quantified. RESULTS: P-SMAD1/5 protein was detected by WB in RA and to a lesser extent in normal synovium. Different P-SMAD1/5 positive cell populations were identified in RA synovium, mainly in perivascular and sublining cells. P-SMAD1/5 positive perivascular cells were alphaSMA positive and located around VWF positive endothelial cells. Some CD90 positive synovial fibroblasts were P-SMAD1/5 positive, as was part of the CD68 positive synovial cells but other cells of the haematopoietic lineage showed no SMAD1/5 phosphorylation. Treatment resulted in an absolute but not relative decrease in BMP activation in the synovium. CONCLUSION: BMP-activated cells belong to distinct stromal compartments in RA synovium and some of them express markers associated with the mesenchymal progenitor cell lineage. Antirheumatic treatment effectively downregulates synovial inflammation, but BMP activation in the synovium does persist albeit reduced.

The in vitro osteogenetic characteristics of primary osteoblastic cells from a rabbit calvarium.

Previously, we showed that recombinant human bone morphogenetic protein-2 (rhBMP-2) increased bone augmentation beyond the skeletal envelope within a titanium cap in a rabbit calvarium; many cuboidal osteoblastic cells were observed histologically. These results suggested that the new osteoblastic cells might have differentiated and matured via stimulation by rhBMP-2. To date, however, no studies have reported the characteristics of osteoblastic cells derived from adult rabbit calvarium, after addition of rhBMP-2. To determine the effects of rhBMP-2 on osteoblastic cells, we observed morphological characteristics and alkaline phosphatase activity of osteoblastic cells from an adult rabbit calvarium. The expression of proteins in the BMP signaling pathway and extracellular matrix were analyzed, and mineralized nodule formation was assessed. The alkaline phosphatase activity increased significantly after rhBMP-2 stimulation. The protein levels of phosphorylated-Smad1, Runx2, osteocalcin, osteopontin, and type I collagen were augmented by rhBMP-2 stimulation using Western blotting or ELISA; rhBMP-2 also stimulated mineralized nodule formation with alizarin red staining. The results suggest that primary osteoblastic cells derived from a rabbit calvarium have osteogenetic characteristics in vitro, underscoring the potential use of these cells as a model for studying bone formation. These cells may play an important role in in vivo bone augmentation in a rabbit experimental model.

Effects of Smads and BMPs induced by Ga-Al-As laser irradiation on calcification ability of human dental pulp cells.

We investigated the effects of Ga-Al-As laser irradiation on the mineralization ability of human dental pulp (HDP) cells and on Smads and bone morphogenetic protein (BMP) production as one mechanism for the transmission of laser photochemical energy to cells. HDP cells in vitro were irradiated once with a Ga-Al-As laser at 1.0 W for 500 s, and calcified nodule formation was assessed by Alizarin red S staining. The laser irradiation was greater in the laser-irradiated group than in the non-irradiated group. Both calcium production and alkaline phosphatase (ALP) activity were higher after laser irradiation. Expression of mRNAs for Smad1, Smad7, BMPs, ALP, and osteocalcin was greater after laser irradiation, whereas expression of Smad6 mRNA was inhibited. Production of BMP-2 and BMP-4 in conditioned medium was also higher after laser irradiation. These results suggest that Smads and BMPs play important roles in ALP activity and calcification upon laser irradiation of HDP cells.