BMP-2 mRNA Expression Research Articles

Abstract 691: Mir-146a as a Modulator and Pathomechanistic Target of Vascular Calcification

Background: Arterial stiffness, which may develop due to vascular calcification, is a significant pathophysiological factor associated with arterial aging or diseases such as type-2 diabetes or end stage renal disease. With no effective therapy clinically available to date, molecular and epigenetic mechanisms of ectopic calcification in conduit arteries are receiving increasing attention to identify targets for therapeutical interference. Here we show that miR-146a may serve as a therapeutic candidate to counteract vascular calcification. Methods: Ectopic calcification was assessed in human aortic smooth muscle cells (AoSMCs) using Alizarin red and Von kossa stainings. The total calcium content in hydroxyapatite crystals was assessed using QuantiChrom TM calcium assay kit. The mRNA expression levels of BMP2, MSX2 and SORT1 were assessed by TaqMan real-time PCR. Results: The endogenous expression of miR-146a was significantly decreased and simultaneously ectopic calcium deposition was significantly increased in AoSMCs exposed to osteogenic stimulation. However, overexpression of miR-146a in AoSMCs cultured in vitro reduced the ectopic calcium deposits. Simultaneously, mRNA expression levels of osteogenic markers and drivers of calcification, such as BMP2, MSX2 and SORT1 - all predicted miR-146a target genes - were significantly reduced. Conversely, significantly increased calcium deposits were observed when miR-146a was inhibited in these cells in similar culture conditions with upregulated BMP2, MSX2 and SORT1 mRNA expression levels. Conclusion: The results suggest that miR-146a may serve as a modulator of AoSMC calcification and miR-146a supplementation may qualify as a therapeutic intervention to counteract vascular calcification due to aging, type-2 diabetes or end stage renal disease.

Impact of miR-302b on Calcium-phosphorus Metabolism and Vascular Calcification of Rats with Chronic Renal Failure by Regulating BMP-2/Runx2/Osterix Signaling Pathway

To investigate how miR-302b affect the calcium-phosphorus metabolism and vascular calcification (VC) of rats with chronic renal failure (CRF) via the regulation of bone morphogentic proteins 2/Runt-related transcription factor 3/Osterix (BMP-2/Runx2/Osterix) signaling pathway. SD rats were selected to establish CRF rat models and assigned into Sham, CRF, CRF+ miR-302b, and CRF+miR-NC groups. The biochemical indexes of rats were detected at 8th and 12th week. Besides, HE staining and Von Kossa staining were performed to monitor renal structural changes and VC respectively; and quantitative real-time PCR (qRT-PCR) and Western blotting to evaluate the expressions of miR-302b and BMP-2/Runx2/Osterix signaling pathway separately. HE and Von Kossa staining showed evident vascular calcification in rats from CRF and CRF+miR-NC groups with a large number of black granules deposited in renal artery compared with Sham group, but was improved in rats in the CRF+miR-302b group compared to those in the CRF group. Besides, rats in the CRF group had elevated levels of Scr, BUN, P, Cys C, and PTH, as well as the mRNA and protein expression of BMP-2, Runx2, and Osterix, and reduced serum Ca and miR-302b levels in a time-dependent manner (all p <0.05), which was in a completely opposite tendency in the CRF+miR-302b group (all p <0.05). miR-302b may improve calcium-phosphorus metabolism, and inhibit VC to alleviate the condition of CRF rats possibly associated with the BMP-2/Runx2/Osterix pathway, opening a new idea for CRF therapy.

Molecular mechanism of quercitrin on osteogenic differentiation and adipogenic differentiation of rat bone marrow stromal stem cells (rBMSCs)

ObjectiveThe study was designed to investigate the molecular mechanism of quercitrin on osteogenic differentiation and adipogenic differentiation of rBMSCs. MethodsrBMSCs were harvested from SD rats, and determination of alkaline phosphatase (ALP) activity, quantification of mineralization by Alizarin Red S staining, and the mRNA expression of osteogenic differentiation markers (Runx2, BMP-2, and OSX) by RT-PCR after rBMSCs stimulated by osteogenic induction with (0.1–10) µg/mL of quercitrin, quantification of Lipid droplet by Oil Red O staining and the mRNA expression of adipogenic differentiation marker (PPARγ, C/EBPα, and aP2) by RT-PCR after rBMSCs stimulated by adipogenic induction with (0.1-10) µg/mL of quercitrin. ResultsQuercitrin can up-regulate the mRNA expression of osteogenic differentiation markers (Runx2, BMP-2, and OSX) and increase ALP activity and mineralization after osteogenic induction, on the other hand quercitrin can suppress the mRNA expression of adipogenic differentiation markers (PPARγ, C/EBPα, and aP2) and decrease lipid droplet after adipogenic induction. ConclusionThis study suggested that quercitrin not only stimulated osteogenic differentiation but also inhibited adipogenic differentiation of rBMSCs, which was associated with the up-regulation of Runx2, BMP-2, and OSX mRNA expression and the down-regulation of PPARγ, C/EBPα, and aP2 mRNA expression.

Wedelolactone Enhances Osteoblastogenesis through ERK- and JNK-mediated BMP2 Expression and Smad/1/5/8 Phosphorylation.

Our previous study showed that wedelolactone, a compound isolated from Ecliptae herba, has the potential to enhance osteoblastogenesis. However, the molecular mechanisms by which wedelolactone promoted osteoblastogenesis from bone marrow mesenchymal stem cells (BMSCs) remain largely unknown. In this study, treatment with wedelolactone (2 μg/mL) for 3, 6, and 9 days resulted in an increase in phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal protein kinase (JNK), and p38. Phosphorylation of mitogen-activated protein kinases (MAPKs), ERK and JNK started to increase on day 3 of treatment, and p38 phosphorylation was increased by day 6 of treatment. Expression of bone morphogenetic protein (BMP2) mRNA and phosphorylation of Smad1/5/8 was enhanced after treatment of cells with wedelolactone for 6 and 9 days. The addition of the JNK inhibitor SP600125, ERK inhibitor PD98059, and p38 inhibitor SB203580 suppressed wedelolactone-induced alkaline-phosphatase activity, bone mineralization, and osteoblastogenesis-related marker genes including Runx2, Bglap, and Sp7. Increased expression of BMP2 mRNA and Smad1/5/8 phosphorylation was blocked by SP600125 and PD98059, but not by SB203580. These results suggested that wedelolactone enhanced osteoblastogenesis through induction of JNK- and ERK-mediated BMP2 expression and Smad1/5/8 phosphorylation.

The inhibitory effect of Aconiti Sinomontani Radix extracts on the proliferation and migration of human synovial fibroblast cell line SW982

Ethnopharmacological relevanceAconiti Sinomontani Radix is frequently used in the treatment of Bi syndrome in traditional Chinese medicine. Several reports indicate that Aconiti Sinomontani Radix has therapeutic effects for rheumatoid arthritis (RA). However, the cellular mode of action is still unclear. To investigate the effect of alkaloid extracts of Aconiti Sinomontani Radix on proliferation and migration of human synovial sarcoma SW982 cells as well as the molecular mechanism underlying. Materials and methodsSW982 cells were examined for proliferation by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method. Wound scratch assays were performed to assess the migrated rate of SW982 cells. Quantitative real-time PCR was used to measure the mRNA expression levels of Wnt5a, Runx2, MMP3, and Bmp2. Western blotting was used to measure the phosphorylated levels of JNK and NF-κB as well as the expression of MMP3. ResultsThe alkaloid extract from Aconiti Sinomontani Radix (MQA) and MQB, which removed lappaconitine from MQA significantly inhibited the proliferation of SW982 in a dose-dependent manner. The proliferation inhibitory effect of MQB was more potent. Incubation with 10μg/ml MQB for 12, 24, and 36h inhibited the migration of SW982 cells by 83%, 58%, and 42%, respectively. Treatment with different concentrations of MQB for 24h inhibited mRNA expression of Wnt5a, Runx2, and MMP3, but Bmp2 mRNA expression was elevated by MQB. Further, MQB inhibited phosphorylation of JNK and NF-κB p65 as well as MMP3 expression by Western blotting analysis. ConclusionThe results showed that MQB inhibited proliferation and migration of SW982 cells possibly through suppressing Wnt5a-mediated JNK and NF-κB pathways. These results indicated that MQB might be an active extract of Aconiti Sinomontani Radix for targeting fibroblast-like synoviocytes (FLS) and be potential for RA therapy.

Implantation of Bone Marrow Stromal Cell Sheets Derived from Old Donors Supports Bone Tissue Formation.

The purpose of this study was to evaluate the osteogenesis ability of osteogenic matrix cell sheets (OMCS) derived from old donor cells. Bone marrow stromal cells (BMSC) were obtained from young (7-week-old) and old (1-year-old) Fischer344 rats donors and cultured with modified Eagle's medium (MEM group) alone or containing dexamethasone (Dex; 10nM) and ascorbic acid phosphate (AscP; 0.28mM) (Dex/AscP group). We prepared four in vitro experimental groups: (1) young MEM, (2) young Dex/AscP, (3) old MEM and (4) old Dex/AscP. Cell proliferation and osteogenic marker mRNA expression levels were evaluated in vitro. To assess bone formation in vivo, the cells of each group were combined with beta tricalcium phosphate (TCP) disks followed by implantation in recipient rats. The in vitro study showed significant differences in the mRNA expression of osteocalcin, ALP, and BMP2 between MEM and Dex/AscP groups. Bone formation following implantation was observed upon histological analyses of all groups. TCP combined with OMCS (OMCS/TCP group) resulted in enhanced bone formation compared to that following combination with BMSC (BMSC/TCP). The osteocalcin content of the OMCS/TCP group 4weeks after implantation was significantly higher than that in the BMSC/TCP construct for both young and old donors. The present study clearly indicated that OMCS could be generated from BMSCs of old as well as young donors using a mechanical retrieval method. Thus, through its usage of OMCS, this method may represent a potentially effective therapeutic option for cell-based therapy in elderly patients.

Dose-dependent effect of radiation on resorbable blast material titanium implants: an experimental study in rabbits

Background: Radiotherapy is a commonly used treatment modality in head and neck cancer; however, it also negatively affects healthy structures. Direct damage to oral soft and hard tissue frequently occurs with radiotherapy. In this study, we aimed to evaluate the effect of radiotherapy on bone surrounding titanium dental implants via biomechanical and molecular methods.Materials and methods: Fifty-four implants were inserted in the left tibiae of 18 adult male New Zealand rabbits (3 implants in each rabbit). After 4 weeks of the implant surgery, the left tibiae of 12 rabbits were subjected to a single dose of irradiation (15 Gy or 30 Gy). Four weeks after the irradiation, rabbits were sacrificed and removal torque test was done for the biomechanical evaluation. Bone morphogenetic protein-2 (Bmp-2) and fibroblast growth factor-2 (Fgf-2) expression analyses were performed with Real-time PCR. Statistical analysis was done using SPSS.Results: The control group showed significantly higher removal torque value than the 15 and 30 Gy irradiation groups, and the 15 Gy irradiation group had higher removal torque value than the 30 Gy irradiation group (p < .001). The 15 Gy and 30 Gy irradiation groups had significantly lower Bmp-2 and Fgf-2 mRNA expressions than the control group (p < .001). In addition, the 30 Gy irradiation group had significantly lower Bmp-2 (p < .01) and Fgf-2 mRNA expressions (p < .001) than the 15 Gy group.Conclusion: Radiotherapy with 15 and 30 Gy doses can adversely affect osseointegration of implants by reducing the quality of bone and impairing the bone-to-implant contact. The mechanism of action seems to be related to alterations in Bmp-2 and Fgf-2 mRNA expressions.

Observation of the influences of diosgenin on aging ovarian reserve and function in a mouse model

BackgroundThe aim of this study was to investigate the impact of diosgenin, an important monomer of sapogenins in yams, on ovarian reserve in a natural aging mice model.Study designThis randomized controlled trial included 60 9-month-old C57 naturally aging female mice. Twenty-one mice were assigned to the dio group and were fed a single dose of diosgenin (200 mg/kg/day) suspended in 0.3% CMC. Twenty mice were assigned to the DHEA group and were fed a single dose of DHEA (1.25 mg/kg/day) suspended in 0.3% CMC. The remaining 20 mice were assigned to the old control group and were fed a single dose of 0.3% CMC. Three months later, the reproductive performance of these female mice was determined by evaluating ovarian follicles and oocyte number and quality in IVF and comparing age-matched and young controls. The impact of NOBOX, GDF9 and BMP15 mRNA expression was also evaluated.ResultsDiosgenin improves ovarian reserve in naturally aging mice in terms of increasing the number of primary follicles (P < 0.05) and serum levels of AMH (P < 0.05).ConclusionsDiosgenin could counteract age-associated ovarian dysfunction by improving the ovarian reserve in a natural aging mice model.

Identifying early pathogenic events during vascular calcification in uremic rats

Vascular calcification in chronic kidney disease is a very complex process traditionally explained in multifactorial terms. Here we sought to clarify relevance of the diverse agents acting on vascular calcification in uremic rats and distinguish between initiating and complicating factors. After 5/6 nephrectomy, rats were fed a 1.2% phosphorus diet and analyzed at different time points. The earliest changes observed in the aortic wall were noticed 11 weeks after nephrectomy: increased Wnt inhibitor Dkk1 mRNA expression and tissue non-specific alkaline phosphatase (TNAP) expression and activity. First deposits of aortic calcium were observed after 12 weeks in areas of TNAP expression. Increased mRNA expressions of Runx2, BMP2, Pit1, Pit2, HOXA10, PHOSPHO1, Fetuin-A, ANKH, OPN, Klotho, cathepsin S, MMP2, and ENPP1 were also found after TNAP changes. Increased plasma concentrations of activin A and FGF23 were observed already at 11 weeks post-nephrectomy, while plasma PTH and phosphorus only increased after 20 weeks. Plasma pyrophosphate decreased after 20 weeks, but aortic pyrophosphate was not modified, nor was the aortic expression of MGP, Msx2, several carbonic anhydrases, osteoprotegerin, parathyroid hormone receptor-1, annexins II and V, and CD39. Thus, increased TNAP and Dkk1 expression in the aorta precedes initial calcium deposition, and this increase is only preceded by elevations in circulating FGF23 and activin A. The expression of other agents involved in vascular calcification only changes at later stages of chronic kidney disease, in a complex branching pattern that requires further clarification.

Neurogenic Processes Are Induced by Very Short Periods of Voluntary Wheel-Running in Male Mice.

Even in the adult mammalian brain progenitor cells proliferate and give rise to young neurons which integrate into the neuronal network. The dentate gyrus possesses such a neurogenic niche reactive to external stimuli like physical activity. In most studies mice or rats have been exposed to wheel running for periods of several weeks to activate neurogenesis while early neurogenic processes induced by very short running periods are less well understood. To address this issue, we allowed male C57Bl/6 mice free access to a running wheel for 2 or 7 days. We injected bromodeoxyuridine (BrdU) before the last running night, respectively, and quantified cell proliferation with immunocytochemistry for BrdU and Ki-67. Furthermore, we performed immunocytochemistry for doublecortin (DCX) and real-time RT-qPCR for NeuroD1 to characterize and quantify changes in neurogenesis on the protein and mRNA level. Real-time RT-qPCR for neurogenic niche factors (BDNF, FGF-2, BMP4, Noggin) was used to detect changes in the molecular composition of the neurogenic niche. Interestingly, we observed that cell proliferation was already affected after 2 days of running showing a transient decrease, which was followed by a rebound with increased proliferation after 7 days. Neurogenesis was stimulated after 2 days of running, reflected by elevated NeuroD1 mRNA levels, and it was significantly increased after 7 days as indicated by DCX immunostaining. On the level of niche factors we observed changes in expression in favor of neuronal differentiation (increased BDNF mRNA expression) and proliferation (decreased BMP4 mRNA expression) already after 2 days, although increased proliferation is reflected on the cellular level only later. In summary, our data show that 2 days of running are sufficient to activate neurogenic processes and we hypothesize that a strong pressure toward differentiation privileges neurogenesis while proliferation lags behind.

The expression of bone morphogenetic protein 4 and its effects in ischemia-anoxemia induced white matter injury model

Objective To investigate the ultrastructural alteration in brain tissues as well as the expression of bone morphogenetic protein(BMP) 4 and its effects on regulating myelination in the process of white matter injury development. Methods A total of 152 Sprague-Dawley newborn rats(3 days old) were randomly divided into white matter injury group(n=76) or control group(n=76). The white matter injury model was established by ligation of the right common carotid artery and hypoxic exposure(8% O2 and 92%N2), and samples were collected at 3 d, 7 d, 14 d and 21 d after operation.Morphological changes of the brain tissues were observed under a light microscope, while myelination was analyzed using a transmission electron microscope.The expression and location of BMP4 and myelin basic protein(MBP), a marker for myelination, was detected by immunohistochemistry staining, expression levels of BMP4 and MBP proteins were analyzed by Western blotting, and BMP4 mRNA expression was measured by real-time PCR. Results Observed under the light microscope, the cellular structure was clear, fibers arranged closely and orderly in the white matter of the control group.Whereas in the white matter injury group, sparse cells, loose mesh shaped white matter, and disorderly oriented fibers were observed.In the control group, myelin sheath had regular morphology, uniform density, and same thickness, observed using the transmission electron microscope.While in the white matter injury group, the myelin sheath was loosened, thinned, lamellar separated, and boundary obscured.Using immunohistochemistry staining, Western blot, and real-time PCR analyses, it was found that the protein and mRNA expression of BMP4 had no significant change with the increase of age in the control group, while it was rapidly increased with the extending of ischemic time in the white matter injury group.Comparing with the control group, the expression of BMP4 was significantly increased since 3 d after operation in the white matter injury group(P<0.05), and the difference between two groups became more significant with the extending of ischemic time.The expression of MBP protein was analyzed by immunohistochemistry staining and Western blot, and a gradual increase was found in both groups with the increase of age.However, the expression of MBP protein was significantly decreased on 14 d and 21 d after operation in the white matter injury group compared with the control group(P<0.05). Conclusion Myelination disorders exists in white matter injury induced by ischemia-anoxemia.Meanwhile, the expression of BMP4 is significantly increased in the white matter injury group, indicating a possibility that BMP4 involves in the regulation of myelination disorders in white matter injury. Key words: Bone morphogenetic protein; Myelin basic protein; White matter injury; Ischemia-anoxemia; Newborn rats,

Bone morphogenetic protein signaling mediated by ALK-2 and DLX2 regulates apoptosis in glioma-initiating cells.

Bone morphogenetic protein (BMP) signaling exerts antitumor activities in glioblastoma; however, its precise mechanisms remain to be elucidated. Here, we demonstrated that the BMP type I receptor ALK-2 (encoded by the ACVR1 gene) has crucial roles in apoptosis induction of patient-derived glioma-initiating cells (GICs), TGS-01 and TGS-04. We also characterized a BMP target gene, Distal-less homeobox 2 (DLX2), and found that DLX2 promoted apoptosis and neural differentiation of GICs. The tumor-suppressive effects of ALK-2 and DLX2 were further confirmed in a mouse orthotopic transplantation model. Interestingly, valproic acid (VPA), an anti-epileptic compound, induced BMP2, BMP4, ACVR1 and DLX2 mRNA expression with a concomitant increase in phosphorylation of Smad1/5. Consistently, we showed that treatment with VPA induced apoptosis of GICs, whereas silencing of ALK-2 or DLX2 expression partially suppressed it. Our study thus reveals BMP-mediated inhibitory mechanisms for glioblastoma, which explains, at least in part, the therapeutic effects of VPA.

Igf1r signalling acts on the anagen-to-catagen transition in the hair cycle.

Insulin-like growth factor 1 (Igf1) is important for skin development and homoeostasis. However, overexpression and inactivation studies have produced variable findings regarding its role in hair follicle (HF) biology. Here, we studied a conditional and inducible knockout of the Igf1 receptor (Igf1r) in keratin 15-expressing bulge cells. Deletion of Igf1r after the development of the skin appendages in K15-Igf1rKO mice showed no abnormalities in epidermal homoeostasis. Numbers of bulge cells were lower in K15-Igf1rKO mice than in controls, without consequences on wound healing, at least in young mice. K15-Igf1rKO HFs entered anagen phase earlier than controls and showed a delay in the anagen/catagen switch. The expression of Bmp-4 mRNA was inhibited in HFs from K15-Igf1rKO . MED1 transcription was impaired in the epidermis of K15-Igf1rKO mice. These findings suggest that Igf1r controls the hair cycle, partly through Bmp-4 activation.

Controlling Abnormal Joint Movement Inhibits Response of Osteophyte Formation.

Objective Osteoarthritis (OA) is induced by accumulated mechanical stress to joints; however, little has been reported regarding the cause among detailed mechanical stress on cartilage degeneration. This study investigated the influence of the control of abnormal joint movement induced by anterior cruciate ligament (ACL) injury in the articular cartilage. Design The animals were divided into 3 experimental groups: CAJM group ( n = 22: controlling abnormal joint movement), ACL-T group ( n = 22: ACL transection or knee anterior instability increased), and INTACT group ( n = 12: no surgery). After 2 and 4 weeks, the knees were harvested for digital microscopic observation, soft X-ray analysis, histological analysis, and synovial membrane molecular evaluation. Results The 4-week OARSI scores showed that cartilage degeneration was significantly inhibited in the CAJM group as compared with the ACL-T group ( P < 0.001). At 4 weeks, the osteophyte formation had also significantly increased in the ACL-T group ( P < 0.001). These results reflected the microscopic scoring and soft X-ray analysis findings at 4 weeks. Real-time synovial membrane polymerase chain reaction analysis for evaluation of the osteophyte formation-associated factors showed that the mRNA expression of BMP-2 and VEGF in the ACL-T group had significantly increased after 2 weeks. Conclusions Typically, abnormal mechanical stress induces osteophyte formation; however, our results demonstrated that CAJM group inhibited osteophyte formation. Therefore, controlling abnormal joint movement may be a beneficial precautionary measure for OA progression in the future.

An assessment of the overexpression of BMP‐2 in transfected human osteoblast cells stimulated by mineral trioxide aggregate and Biodentine

To evaluate the effect of MTA and Biodentine on viability, osteogenic differentiation and BMP-2 expression in osteogenic cells. Saos-2 cells were used as a model of osteoblastic cells. Overexpression of BMP-2 was induced by transfection of a CMV-driven plasmid construct including the human BMP-2 coding sequence, and stably transfected cells were selected. Cell viability was assessed by the mitochondrial dehydrogenase enzymatic (MTT) assay. The bioactivity of the materials was evaluated by the alkaline phosphatase (ALP) assay and detection of calcium deposits with alizarin red staining (ARS). The gene expression of BMP-2 and ALP was quantified with real-time PCR. Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α=0.05). Viability tests revealed that MTA and Biodentine were not cytotoxic at the higher dilution (1:8) to BMP-2-transfected cells. MTA and Biodentine exhibited the highest ALP activity when compared to the Saos-BMP-2-unexposed control group (P<0.05). Cell exposure to Biodentine and MTA had a significant stimulatory effect on the formation of mineralized nodules (P<0.05). The highest increase in BMP-2 gene expression was observed after 3days of BMP-2-transfected cells exposure to MTA and Biodentine in non-osteogenic medium in relation to Saos-BMP-2-unexposed control cells (P<0.05). Exposure of cells to MTA in osteogenic medium for 1day increased ALP gene expression by approximately 1.3-fold in relation to Saos-BMP-2-unexposed control cells (P<0.05). Both MTA and Biodentine showed biocompatibility and bioactivity in Saos-BMP-2 overexpressing cells. Biodentine had a significantly greater effect on mineralization than MTA. Both MTA and Biodentine enhanced BMP-2 mRNA expression in the transfected system. Both MTA and Biodentine are suitable materials to improve osteoblastic cell mineralization.

Synthesis and biological evaluation of heterocyclic analogues of pregnenolone as novel anti-osteoporotic agents

The structural modifications of pregnenolone have been described via the introduction of heterocyclic moieties at C-17 position by limiting the acyl group. Novel heterocyclic analogues of pregnenolone have been synthesized by using Friedlander and Claisen-Schmidt reactions, and the synthesized compounds were evaluated for their osteogenic activity. Among the synthesized derivatives, four compounds showed significantly increased ALP activity. Among all four active compounds, the novel compound 3a has shown significant bone matrix mineralization and mRNA expressions of osteogenic marker genes, BMP2, RUNX-2 and OCN at 1pM concentration.

Silicate-based bioceramics regulating osteoblast differentiation through a BMP2 signalling pathway.

Bioactive materials with osteostimulation properties have the potential to promote bone regeneration. We have found that silicate-based biomaterials have the osteostimulation ability for regeneration of large bone defects; however, the corresponding mechanism is unclear. In this study, we set out to elucidate the potential mechanism of silicate-based biomaterials with osteostimulation ability. A model silicate bioceramic, nagelschmidtite (NAGEL, Ca7P2Si2O16), was applied to study their ionic products on the effect of the Bone morphogenic protein (BMP) signaling pathway for osteoblast MC3T3-E1 as NAGEL has been previously shown to have excellent in vitro and in vivo bone-forming activity. BMP signaling, especially BMP2, is involved in bone formation during mammalian development and exhibits versatile regulatory functions in the body. It is found that NAGEL bioceramics significantly enhance the migration and osteoblastic differentiation of MC3T3-E1. mRNA and protein expression of BMP2 is enhanced by NAGEL bioceramics in a dose-dependent manner. Moreover, NAGEL bioceramics activate the Smad-dependent BMP signaling pathway and induce the activation of the BMP downstream cascade (OCN, OPN and Runx2). The accumulation of phosphorylated-Smad1/5 is induced by NAGEL bioceramics in the MC3T3-E1 cell nucleus. It is further found that NAGEL bioceramic-mediated migration, osteoblastic differentiation and the activation of the BMP downstream cascade are significantly downregulated by inhibition of BMP2 activity. Our results suggest that silicate-based NAGEL bioceramics possess excellent in vitro osteostimulation properties and the possible mechanism of silicate-based biomaterials with distinct osteostimulation may be directly related to the activation of the BMP2 signaling pathway of osteoblasts by release of Si-containing bioactive ionic products.

MicroRNA-98 regulates osteogenic differentiation of human bone mesenchymal stromal cells by targeting BMP2.

To study the effects of microRNA‐98 (miR‐98) on human bone mesenchymal stromal cells (hBMSCs). The patients undergoing hip arthroplasty were selected by inclusion/exclusion criteria for this study. The extracted hBMSCs were detected of osteogenic differentiation by alizarin red S staining, and of cell phenotype by flow cytometry. Bioinformatics, dual luciferase report, western blotting, RT‐PCR and immunoblotting were used in our study. The hBMSCs were divided into miR‐98 mimics, miR‐98 negative control (NC), miR‐98 inhibitors, Mock and miR‐98 inhibitors + siBMP2 groups. Human bone mesenchymal stromal cells were extracted and purified in vitro and had specific cytological morphology, surface markers and abilities of self‐renewal and differentiation. Compared with the NC group and Mock group, the miR‐98 mimics group showed increased miR‐98 level while the miR‐98 inhibitors group decreased miR‐98 level (both P < 0.01). Dual luciferase reporter showed BMP2 was the target gene of miR‐98. The levels of mRNA and protein expression of BMP2, protein expression of RUNX2, alkaline phosphatase activity and osteocalcin content significantly decreased in the miR‐98 mimics group while increased in the miR‐98 inhibitors group and showed no changes in the NC group and Mock group (all P < 0.05). The miR‐98 mimics group showed obviously declined stained red particles and the miR‐98 inhibitors group showed opposite result. After lowering the expression of miR‐98, osteogenic differentiation ability of hBMSCs rose, which was weakened by the transfection with siBMP2. miR‐98 may regulate osteogenic differentiation of hBMSCs by targeting BMP2.

Regulation and function of bone morphogenetic protein signaling in colonic injury and inflammation.

In this study we report a series of novel observations that underscore the importance of bone morphogenetic protein (BMP) signaling in the regulation of colonic homeostasis during the development of injury and inflammation. In particular, we present evidence that BMP signaling mitigates the response of the colonic epithelium to injury and inflammation and that cytokines, such as TNF-α and IL-1β, inhibit the expression of BMP-4.

Primary cilium is required for the stimulating effect of icaritin on osteogenic differentiation and mineralization of osteoblasts in vitro.

Icaritin, one effective metabolite of Herba Epimedii-derived flavonoid icariin, has a strong osteogenic activity. However, its action mechanism remains unclear. Since primary cilia have been shown to play a pivotal role in regulating the osteogenesis, we hypothesized primary cilia are indispensable in mediating icaritin osteogenic effect. Primary rat calvarial osteoblasts were transfected with siRNA1 targeting intraflagellar transport protein 88 (IFT88), a protein required for ciliogenesis, to prevent formation of primary cilium and were treated with 10-6M icaritin. Alkaline phosphatase (ALP) activity was significantly increased after 3days in cells transfected with scrambled siRNA control and treated by icaritin (SC+I group) compared to cells transfected with scrambled siRNA control only (SC group). ALP activity after IFT88 siRNA1 transfection and icaritin treatment (siRNA1+I group) was significantly lower than that of SC+I group. Formation of ALP positively stained colonies after 6days, osteocalcin secretion after 9days and formation of calcified nodules after 12days displayed a similar tendency among the three groups. mRNA expression of osteogenesis-related genes ALP, BMP-2, COL1α, RUNX-2 and OSX after 24h was significantly increased in SC+I group, but was not different with SC group in siRNA1+I group. Protein levels of BMP-2, COL1α, RUNX-2 and OSX after 48h showed the similar tendency with gene expression. Primary cilia are important in mediating icaritin-stimulated osteogenic differentiation and may be a novel target for pharmacological therapies for bone loss.