Bone Morphogenetic Protein-2 Levels Research Articles

In Vitro and In Vivo Osteogenesis Induced by Icariin and Bone Morphogenetic Protein-2: A Dynamic Observation.

In the present study, we aimed to compare the effects of icariin (ICA) and bone morphogenetic protein-2 (BMP-2) on osteoblast proliferation and osteogenesis in bone defects. We found that in vitro ICA or BMP-2 treatment is able to increase osteoblast proliferation, which was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Specifically, ICA at a concentration of 30 µg/ml had the strongest ability to promote cell proliferation, which is equivalent with the effect of BMP-2 at a concentration of 50 µg/ml. Furthermore, Western blot and RT-qPCR analyses showed that treatment with ICA (20–30 µg/ml) had similar increase effect with BMP-2 (50 µg/ml) on the protein and mRNA levels of BMP-2, osteoprotegerin (OPG), and alkaline phosphatase (ALP) mRNAs. In addition, the animal model of bone defects was successfully prepared. The in vivo data showed that compared with the control group, highest osteogenesis in the ICA or BMP-2 groups was observed at different observational times. Four weeks after surgery, osteogenesis in the BMP-2 group was slightly higher than that in the ICA group, but there was no significant difference between the two groups until the eighth week. ICA promotes osteoblast proliferation by stimulating the expression of BMP-2 and OPG proteins and upregulating the expression of BMP-2, OPG, and ALP mRNAs. ICA at a certain concentration has the same osteogenic effect as BMP-2. ICA or BMP-2 composite nanomaterials can be used as a framework to guide bone regeneration and promote osteogenesis. In addition, the combined use of hematoxylin-eosin and Goldner’s trichrome staining techniques contributes to acquiring better bone morphometric information about bone defects.

The Association Between Traumatic Brain Injury and Accelerated Fracture Healing: A Study on the Effects of Growth Factors and Cytokines.

Evidence suggests that some systemic and local factors, including cytokines and growth factors in patients with traumatic brain injury (TBI), can play an essential role in accelerating fracture healing. The purpose of this study was to evaluate serum levels of some inflammatory cytokines and growth factors in patients with fracture and TBI as well as healthy subjects. In this study, a total number of 30 patients with a femoral fracture, 30 cases with TBI, 30 patients with TBI and a femoral fracture (fracture + TBI group), and 30 healthy subjects were recruited. The Glasgow Coma Scale (GCS) scores were also determined upon their admission. Then, the serum levels of fibroblast growth factor 2 (FGF-2), transforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), bone morphogenetic protein 2 (BMP-2), insulin-like growth factor 1 (IGF-1), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) were measured via enzyme-linked immunosorbent assay (ELISA) technique, 12h and 4weeks after injury and hospital admission. The study results demonstrated that the serum levels of BMP-2, FGF-2, IL-1β, and PDGF in the femoral fracture + TBI group increased significantly over 12h and after 4weeks compared with other groups, but the serum levels of IGF-I, IL-6, and TGF-β in this group increased in a significant manner at 12h compared with other studied groups. The findings also showed that the time to union of a femoral fracture was shorter in the fracture + TBI group than in cases with a femoral fracture alone (p= 0.03). Accordingly, it seems that elevated serum levels of BMP-2, PDGF, FGF-2, and IL-1β may be associated with healing acceleration in fracture + TBI patients. However, further studies are needed to confirm this claim.

Therapeutic effect of heat-sensitive moxibustion plus medications for senile osteoporosis and its effect on serum BMP-2 and OPG levels

To observe the clinical efficacy of heat-sensitive moxibustion plus medications on senile osteoporosis (SOP), and to explore the related mechanisms. A total of 70 elderly participants with osteoporosis were randomly divided into an observation group and control group, with 35 cases in each group. The control group was treated with conventional drugs, and the observation group was treated with heat-sensitive moxibustion on the basis of the conventional drugs. Both groups were treated for 3 months. Before and after treatment, assessed the visual analog scale (VAS) and Oswestry disability index (ODI) scores, determined the bone mineral density of the participants’ lumbar spine (L2-L4) and left femoral neck, and detected the participants’ serum bone morphogenetic protein-2 (BMP-2) and osteoprotegerin (OPG) levels. After treatment, the VAS scores of both groups were lower than before treatment (both P<0.05), and the VAS score of the observation group was significantly lower than that of the control group (P<0.05). After treatment, the bone mineral density values of the lumbar spine and left femoral neck in both groups were significantly higher than before treatment (both P<0.05), and the bone mineral density values of the observation group were higher than those of the control group (P<0.05). After treatment, the ODI scores of the two groups were lower than those before treatment (both P<0.05), and the ODI score of the observation group was lower than that of the control group (P<0.05). After treatment, the serum BMP-2 and OPG levels in the observation group were significantly higher than those in the control group (both P<0.05). Heat-sensitive moxibustion plus medications for SOP can significantly relieve patients’ pain, improve dysfunction, and increase bone density, which may be related to the improvement of the serum BMP-2 and OPG levels.

Expression and distribution of bone morphogenetic protein 4 and its antagonist Noggin in the skin of Kazakh sheep (Ovis aries) with a white and brown coat color

The natural coat color is an important trait of vertebrate animals. For example, the coat color can help avoid harm to human beings caused by chemical dyeing, and it has economic significance for domestic animals. The bone morphogenetic protein 4 (BMP4) and its antagonist Noggin can regulate pigmentation and the generation of coat color in mice; thus, they may also regulate the coat color of Kazakh sheep. To gain mechanistic insight into this possibility, we determined the relative expression levels of BMP4 and Noggin in the skin of white and brown Kazakh sheep by quantitative real-time polymerase chain reaction (qPCR) and western blotting analysis. The localization of BMP4 and Noggin were detected by immunohistochemistry (IHC). The results of qPCR and western blot analysis demonstrated that the relative expression levels of BMP4 and Noggin in the skin of brown Kazakh sheep were significantly higher than those in white Kazakh sheep. Our IHC results showed that the BMP4 protein was expressed in the epidermis and root sheath of the Kazakh sheep skin. The Noggin protein was expressed in the epidermis, root sheath, hair shaft, and dermal papilla of the Kazakh sheep skin. These results provide a theoretical basis for additional studies regarding the association and mechanism of BMP4 and Noggin in coat-color formation in Kazakh sheep. These results may provide new methods for developing treatment strategies for pigmentation disorders and diseases.

Platelet Rich Fibrin (PRF) and Its Related Products: Biomolecular Characterization of the Liquid Fibrinogen.

Liquid fibrinogen is an injectable platelet concentrate rich in platelets, leukocytes, and fibrinogen obtained by blood centrifugation. The aim of this study was to analyze the release of different growth factors in the liquid fibrinogen at different times and to assess possible correlations between growth factors and cell counts. The concentration of transforming growth factor beta 1 (TGF-β1), platelet-derived growth factor-AB (PDGF-AB), platelet-derived growth factor-BB (PDGF-BB), bone morphogenetic protein 2 (BMP-2), fibroblast growth factor 2 (FGF-2) and vascular endothelial growth factor (VEGF) released by liquid fibrinogen were examined with ELISA at three time points (T0, time of collection; T7, 7 days; T14, 14 days). The cellular content of the liquid fibrinogen and whole blood was also calculated for each volunteer. A mean accumulation of platelets of almost 1.5-fold in liquid fibrinogen compared to whole blood samples was found. An increase of TGF-β1, PDGF-AB, FGF-2, and VEGF levels was detected at T7. At T14, the level of TGF-β1 returned to T0 level; PDGF-AB amount remained high; the levels of FGF-2 and VEGF decreased with respect to T7, but remained higher than the T0 levels; PDGF-BB was high at all time points; BMP-2 level was low and remained constant at all time points. TGF-β1, PDGF-AB, and PDGF-BB showed a correlation with platelet amount, whereas BMP-2, FGF-2, and VEGF showed a mild correlation with platelet amount. Due to the high concentration of platelets, liquid fibrinogen does contain important growth factors for the regeneration of both soft and hard tissue. The centrifugation protocol tested in this study provides a valid solution to stimulate wound healing in oral and periodontal surgery.

Noggin Inhibits IL-1β and BMP-2 Expression, and Attenuates Cartilage Degeneration and Subchondral Bone Destruction in Experimental Osteoarthritis.

Osteoarthritis (OA) is a chronic inflammatory and progressive joint disease that results in cartilage degradation and subchondral bone remodeling. The proinflammatory cytokine interleukin 1 beta (IL-1β) is abundantly expressed in OA and plays a crucial role in cartilage remodeling, although its role in the activity of chondrocytes in cartilage and subchondral remodeling remains unclear. In this study, stimulating chondrogenic ATDC5 cells with IL-1β increased the levels of bone morphogenetic protein 2 (BMP-2), promoted articular cartilage degradation, and enhanced structural remodeling. Immunohistochemistry staining and microcomputed tomography imaging of the subchondral trabecular bone region in the experimental OA rat model revealed that the OA disease promotes levels of IL-1β, BMP-2, and matrix metalloproteinase 13 (MMP-13) expression in the articular cartilage and enhances subchondral bone remodeling. The intra-articular injection of Noggin protein (a BMP-2 inhibitor) attenuated subchondral bone remodeling and disease progression in OA rats. We also found that IL-1β increased BMP-2 expression by activating the mitogen-activated protein kinase (MEK), extracellular signal-regulated kinase (ERK), and specificity protein 1 (Sp1) signaling pathways. We conclude that IL-1β promotes BMP-2 expression in chondrocytes via the MEK/ERK/Sp1 signaling pathways. The administration of Noggin protein reduces the expression of IL-1β and BMP-2, which prevents cartilage degeneration and OA development.

Activation of Canonical BMP4-SMAD7 Signaling Suppresses Breast Cancer Metastasis.

Metastasis is the major cause of death in patients with cancer; with no therapeutic cure, treatments remain largely palliative. As such, new targets and therapeutic strategies are urgently required. Here, we show that bone morphogenetic protein-4 (BMP4) blocks metastasis in animal models of breast cancer and predicts improved survival in patients. In preclinical models of spontaneous metastasis, BMP4 acted as an autocrine mediator to modulate a range of known metastasis-regulating genes, including Smad7, via activation of canonical BMP-SMAD signaling. Restored BMP4 expression or therapeutically administered BMP4 protein, blocked metastasis and increased survival by sensitizing cancer cells to anoikis, thereby reducing the number of circulating tumor cells. Gene silencing of Bmp4 or its downstream mediator Smad7, reversed this phenotype. Administration of recombinant BMP4 markedly reduced spontaneous metastasis to lung and bone. Elevated levels of BMP4 and SMAD7 were prognostic for improved recurrence-free survival and overall survival in patients with breast cancer, indicating the importance of canonical BMP4 signaling in the suppression of metastasis and highlighting new avenues for therapy against metastatic disease. SIGNIFICANCE: Targeting the BMP4-SMAD7 signaling axis presents a novel therapeutic strategy to combat metastatic breast cancer, a disease that has had no reduction in patient mortality over 20 years. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/6/1304/F1.large.jpg.

High Levels of BMP2 Promote Liver Cancer Growth via the Activation of Myeloid-Derived Suppressor Cells.

Bone morphogenetic protein 2 (BMP2) signaling had significant roles in diverse pathological processes, such as cancer. Nevertheless, the interaction between BMP2 and carcinoma development remained largely unknown. In particular, the roles that BMP2 play in the development of liver cancer remained controversial, and mechanisms were unclear. BMP2 with strong osteogenic potential had been manufactured into various bone materials. However, cancer risk concerns were raised in recent years. Thus, we focused on analyzing the effects of exogenous BMP2 on the growth of liver cancer and the detailed mechanisms. We found that both intravenous injection of rhBMP2 and in vivo implantation of rhBMP2 materials could lead to the expansion of myeloid-derived suppressor cells (MDSCs) in peripheral blood and subsequently enhanced the infiltration of MDSCs into tumor in vivo. Furthermore, BMP2 signaling-activated MDSCs could secrete IL6 to enhance cell proliferation of liver cancer cells in vitro and facilitate liver cancer growth in vivo. Our study indicated that increased concentration of BMP2 within the peripheral blood could enhance liver cancer growth via the activation of MDSCs. In this study, the roles that BMP2 played in liver cancer growth were further confirmed and the detailed mechanisms about how BMP2 enhanced liver cancer growth were also elucidated.

Effect of strontium ranelate on rabbits with steroid-induced osteonecrosis of femoral head through TGF-β1/BMP2 pathway.

To study the effect of strontium ranelate (SR) on steroid-induced osteonecrosis of the femoral head (SIONFH) in rabbits and its regulatory mechanism. The ONFH model was established in 30 rabbits using steroid and they were randomly divided into Control group, Model group, and SR group. After SR intervention, the rabbits were sacrificed and sampled. The pathological injury of the femoral head in each group was detected via hematoxylin-eosin (HE) staining, the level of vascular endothelial growth factor (VEGF) in the femoral head in each group was detected via enzyme-linked immunosorbent assay (ELISA). The messenger ribonucleic acid (mRNA) and protein expression levels of transforming growth factor-β1 (TGF-β1), as well as the bone morphogenetic protein 2 (BMP2) in the femoral head in each group, were determined using Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting. The rabbit model of SIONFH was successfully established. Compared with Control group, the Model group had a severer pathological injury of the femoral head, a lower level of VEGF in the femoral head, significantly decreased mRNA and protein levels of TGF-β1 and BMP2. Compared with Model group, the SR group had markedly improved pathological injury of the femoral head, a higher level of VEGF in the femoral head, significantly increased mRNA and protein levels of TGF-β1, as well as BMP2. SR can remarkably improve the pathological injury of the femoral head and increase the expression of VEGF in SIONFH rabbits, whose potential mechanism may be related to the activation of the TGF-β1/BMP2 signaling pathway.

Enhancing Activity of Pleurotus sajor-caju (Fr.) Sing β-1,3-Glucanoligosaccharide (Ps-GOS) on Proliferation, Differentiation, and Mineralization of MC3T3-E1 Cells through the Involvement of BMP-2/Runx2/MAPK/Wnt/β-Catenin Signaling Pathway.

Osteoporosis is a leading world health problem that results from an imbalance between bone formation and bone resorption. β-glucans has been extensively reported to exhibit a wide range of biological activities, including antiosteoporosis both in vitro and in vivo. However, the molecular mechanisms responsible for β-glucan-mediated bone formation in osteoblasts have not yet been investigated. The oyster mushroom Pleurotus sajor-caju produces abundant amounts of an insoluble β-glucan, which is rendered soluble by enzymatic degradation using Hevea glucanase to generate low-molecular-weight glucanoligosaccharide (Ps-GOS). This study aimed to investigate the osteogenic enhancing activity and underlining molecular mechanism of Ps-GOS on osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. In this study, it was demonstrated for the first time that low concentrations of Ps-GOS could promote cell proliferation and division after 48 h of treatment. In addition, Ps-GOS upregulated the mRNA and protein expression level of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), which are both involved in BMP signaling pathway, accompanied by increased alkaline phosphatase (ALP) activity and mineralization. Ps-GOS also upregulated the expression of osteogenesis related genes including ALP, collagen type 1 (COL1), and osteocalcin (OCN). Moreover, our novel findings suggest that Ps-GOS may exert its effects through the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways.

Osteoprotegerin/bone morphogenetic protein 2 combining with collagen sponges on tendon-bone healing in rabbits.

The aim was to investigate the effect of collagen sponges (CS) as a delivery device for osteoprotegerin (OPG)/bone morphogenetic protein 2 (BMP-2) and support matrix on the tendon-bone healing after anterior crusicate ligament (ACL) reconstruction in modeled rabbits. Sixty New Zealand white rabbits were randomly divided into four groups based on treatments they received at the tendon-bone interface after left knee ACL reconstruction: the control group, OPG/BMP-2, CS, and OPG/BMP-2/CS combination. At 4, 8 and 12weeks post-surgery, five rabbits from each group were euthanized to examine the tendon-bone healing. Levels of OPG and BMP-2 in synovial fluid, the bone tunnel enlargement value, the histomorphological typing of tendon-bone interface, and the bone tunnel area of the tendon-bone interface were compared among different treatments. The OPG/BMP-2/CS combination treatment group had the highest levels of OPG and BMP-2 in synovial fluid (both P < 0.05), the greatest number of Sharpey-like collagen fibers at all test points (P < 0.05), the most fibrocartilage enthesis on week 12, the greatest bone tunnel area (P < 0.05), and the greatest decrease in bone tunnel enlargement on week 12 (P < 0.05). Histomorphological typing of tendon-bone interface of all groups showed changes varying from tendon-bone separation to firm healing, and the change was most significant in the OPG/BMP-2/CS combination treatment group. CS treatment alone serves as a fixing support, and CS combining with growth factors OPG/BMP-2 ensures slow and stable release of OPG/BMP-2, significantly improves the tendon-bone healing in the rabbit ACL model.

Free and liposome form of gallic acid improves calvarial bone wound healing in Wistar rats

Objective: To evaluate the effect of free and liposome form of gallic acid on bone regeneration in critical defects in Wistar rats. Methods: Thirty-two female Wistar rats were divided into four study groups: group 1, negative control; group 2, positive control; group 3, gallic acid powder; group 4, gallic acid liposome. A critical-sized defect was created in all rats. Groups 2 to 4 had xenograft, autograft and membrane placement while negative control rats did not receive any treatment. The defect area was sutured and rats were kept alive for 30 d. At the end of the study, a bone specimen including the defect area was removed from calvaria. All specimens were evaluated under the stereomicroscope, then underwent histological analysis. Inflammatory cell counts, osteoblast, osteoclast counts, receptor activator of nuclear factor κ-B (RANKL), osteoprotegerin (OPG), runt-related transcription factor 2 (Runx2), bone morphogenetic protein-2 (BMP-2), and alkaline phosphatase were determined. Results: The biggest unhealed defect area was observed in the negative control group and the smallest was observed in the gallic acid liposome group. There were no differences between the positive control group vs. the gallic acid powder group and the gallic acid powder group vs. the gallic acid liposome group. The severity of inflammation was the highest in the negative control group and the lowest in the gallic acid liposome group with significant differences between the groups. All groups had similar osteoblast counts while osteoclast counts were the highest in the positive control group. Gallic acid groups had a lower number of osteoclasts compared with the positive control group. Runx2 and alkaline phosphatase levels were similar in the groups while OPG and BMP-2 levels exhibited a significant increase compared with the negative control group and the positive control group. RANKL was similar in the negative control group, the positive control group, and the gallic acid powder groups but decreased in the gallic acid liposome group. Conclusions: Gallic acid powder and liposome significantly improve bone regeneration in Wistar rats with calvarial defects. The improvement in healing is evident with decreased inflammation and RANKL expressions and increased OPG and BMP-2 expressions.

Production of osteogenic and angiogenic factors by microencapsulated adipose stem cells varies with culture conditions.

Growth factors produced by stem cells aid in the bone repair process. We investigated the ability of encapsulated rat adipose-derived stem cells (rASCs) treated with osteogenic media (OM) to produce growth factors, and determined the optimal combination of OM components that will lead to the production of both osteogenic and angiogenic factors. Our results demonstrate that microencapsulated stem cells were able to produce vascular endothelial growth factor (VEGF), fibroblast growth factor-2, and bone morphogenetic protein-2 (BMP2) necessary for bone regeneration. OM led to the reduction of angiogenic factors; however, the removal of dexamethasone restored angiogenic factor production. Additionally, we determined whether the effect of dexamethasone on VEGF and BMP2 varied among rat, rabbit, mouse, and humans. Dexamethasone led to a reduction in VEGF levels in ASCs derived from rats, mice, and humans, while this reduction was absent in rabbit ASCs (rbASCs). Human ASCs (hASCs) from donors of different race and sex showed a similar response to dexamethasone with secreted VEGF levels. BMP2 levels secreted by rbASCs, mouse ASCs (mASCs), and hASCs were independent of the media treatments, while rASCs responded differently in the surrounding media and within the microbeads. In conclusion, microencapsulated ASCs can be treated to produce osteogenic and angiogenic factors for tissue regeneration applications, but outcomes may vary with culture conditions.

Effect of anatomical location (mandible vs maxilla) of dental implants on the BMP-2, BMP-7, sRANKL and OPG levels in periimplant crevicular fluid during osseointegration. A pilot study

Background:The aim of this study was to investigate levels of bone morphogenetic protein-2 (BMP-2), BMP-7, soluble receptor activator of nuclear factor-kB ligand (sRANKL) and osteoprotegerin (OPG) in the peri-implant crevicular fluid (PICF) of implants placed in both maxilla and mandible during the osseointegration period.Methods:Thirty-three patients (17 females and 16 males; mean age 47.03±11.23 years) were included in this study. A total of 33 implants were placed in both of maxilla (Group 1/n=18) and mandible (group 2/n=15). Peri-implant crevicular fluid (PICF) samples, modified plaque index (MPI), gingival index (GI) and probing depth (PD) measurements were obtained at 1 and 3 months after surgery. PICF levels of BMP-2/-7, sRANKL and OPG were analyzed by ELISA.Results:No complications were observed during the healing period. No significant differences were observed in the PICF levels of sRANKL, OPG, BMP-2 and BMP-7 and evaluated clinical parameters between groups at any time point (p&amp;gt;0.05). While PICF volume of group 2 was greater than group 1 at first month, PICF volume of group 1 was greater than group 2 at 3 months (p&amp;lt;0.05). There was a positive correlation between sRANKL levels and PICF volume (p&amp;lt;0.05) and a strong correlation between BMP-2 and BMP-7 (p&amp;lt;0.01).Conclusions:The results of this pilot study didn’t show any significant difference in PICF levels of BMP-2, BMP-7, sRANKL, and OPG in terms of anatomic location of dental implants. Further well-designed studies should be carried out to evaluate the relationship between bone related biomarkers and anatomic location of dental implants.

Impact of Hyperbaric Oxygen on the Healing of Teeth Extraction Sockets and Alveolar Ridge Preservation.

The purpose of this study was to investigate the role of hyperbaric oxygen (HBO) in the healing of teeth extraction sockets and in alveolar ridge preservation. This may provide an experimental basis for the widespread application of HBO in oral implantation. A total of 32 beagle dogs were included in the study and randomly divided equally between an HBO group treated with hyperbaric oxygen (100% O2, 2.4 atm, 90 min/day, 5 times/week, 6 weeks) and a normobaric oxygen (NBO) group treated with normal air in the same chamber. The lateral incisors of the maxillary and mandible of each dog were extracted, and the right upper and lower incisor extraction sockets (A2C2) were allowed to heal naturally, while left upper and lower incisor sockets (B2D2) received implants of a commercial bone substitute. At 4 and 8 weeks after surgery, clinical observation, cone-beam computerized tomography (CBCT), histomorphology observation, and expression levels of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) were analyzed to evaluate new bone formation, mineralization, and reconstruction. After 4 and 8 weeks, bone width and lip contour of the extraction socket in the NBO group were significantly reduced and collapsed in comparison with the HBO group. CBCT showed that the difference in vertical height between the alveolar crest of the labial tongue and palatal side of the extraction sockets was smaller in the HBO than NBO group. There was a significant difference in new bone formation (P < 0.05) and bone mineral density (P < 0.05) between the HBO and NBO groups, and the HBO group showed significantly greater new bone and bone reconstruction based on histology. Furthermore, the expression levels of VEGF and BMP-2 were higher in the HBO group. HBO reduced bone resorption and promoted early bone formation, bone mineralization, and reconstruction in the extraction sockets. HBO greatly reduced the healing time of the extraction sockets and promoted alveolar ridge preservation, thus showing promise for the clinic.

Up-regulation of bone morphogenetic protein and its signaling molecules following castration of bulls and their association with intramuscular fat content in Korean cattle

We evaluated whether castration affects bone morphogenetic protein 2 (BMP2) level and the expression of its signaling molecules in Korean cattle bulls. We also checked whether castration affects the expression of muscle fiber type and oxidative and glycolytic enzyme genes. Enzyme-linked immunosorbent assays revealed that steers had higher plasma BMP2 and leptin concentrations than bulls. Quantitative real-time PCR showed that steers had higher mRNA levels of the lysyl oxidase gene, a downstream target of the BMP signaling pathway, in the longissimus thoracis (LT) muscle. Steers had higher adipogenic peroxisome proliferator-activated receptor gamma and lipogenic fatty acid binding protein 4 mRNA levels in the LT than bulls. Steers had lower mRNA levels for several muscle fiber type 1 genes and fiber type 2A myosin heavy chain 2 gene than bulls. Steers had higher mRNA levels of the glycolytic enzyme phosphoglycerate kinase 1 gene than bulls. Transcript levels of oxidative enzyme genes did not differ between bulls and steers. Regression analysis revealed a positive association between plasma BMP2 levels and intramuscular fat (IMF) content in the steer group. These findings suggest that upregulation of the BMP signaling pathway in response to castration induces increased adipogenic gene expression, contributing to the increased IMF deposition observed in castrated animals.

Knockout of TLR4 promotes fracture healing by activating Wnt/β-catenin signaling pathway

ObjectivesThe aim of this study was to investigate the effect of Toll like receptor 4 (TLR4) on fracture healing. MethodsThe open tibial fracture models in TLR4 knockout (TLR4−/−) and wild type (WT) C57BL-6 J mice were established. The radiological examination, tartrate-resistant acid phosphatase (TRAP) staining, Micro-CT scan and biological torsion test were performed on 7, 14 and 21 days after operation. Enzyme Linked Immunosorbent Assay (ELISA) kit was used to detect the expression levels of tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β) and interleukin 6 (IL-6). Western blotting was used to detect the expression of β-catenin, Wingless-type MMTV integration site family, member 4 and 5B (Wnt4 and Wnt5B), proliferating cell nuclear antigen (PCNA) and bone morphogenetic protein-2 (BMP-2) of the callus tissue obtained from mice. ResultsTLR4 knockout promoted fracture healing, reduced the number of osteoclasts, increased bone callus volume (BV) and callus mineralized volume fraction (BV/TV%) (P < 0.05), increased the maximum torque and torsional stiffness of callus (P < 0.05), reduced TNF-α, IL-1β and IL-6 expression (P < 0.01), and increased the expression levels of β-catenin, Wnt4, Wnt5B, PCNA and BMP-2 (P < 0.01). ConclusionTLR4 knockout reduced inflammatory and promoted fracture healing by activating Wnt/β-catenin signaling pathway.

P5991Cellular mechanisms of aortic valve calcification in primary human valvular interstitial cell culture

Abstract Background Aortic stenosis (AS) is the most common acquired valvular heart disease. Calcification of the aortic valve (AV) cusps is the main pathogenetic mechanism of AS formation, however triggering and progression mechanisms of it are not fully understood. Aortic valve interstitial cells (AVIC) are one of the main cell populations responsible for the AV structure and homeostasis. The aim of the study was to characterize the ability of AVIC to osteogenic differentiation using the model of the primary culture of AVIC of patients with aortic stenosis and assess the expression of genes involved in osteogenesis (RUNX2, BMPG2, SPRY1, SOX9, CTNNB1, POSTN, OPG and OPN). Materials and methods The study was carried out on primary human AVIC culture obtained by enzymatic dissociation of experimental valve specimens from patients with AS (n=15) and the control specimens from the orthotopic heart transplantation recipients (n=10). To assess the osteogenic potential of AVIC, the routine stem cell osteodifferentiation protocol based on the culture medium with addition of inductors (10 mM β-glycerophosphate, 0.1 μM dexamethasone, and 50 μg/ml ascorbic acid) was used. Calcium deposits were demonstrated by Alizarin Red staining. Analysis of the expression of osteogenic differentiation genes, such as RUNX2 (runtrelated transcription factor 2), BMP2 (bone morphogenetic protein 2), SPRY1 (Sprouty RTK signaling antagonist 1), SOX-9 (SRY-box9), CTNNB1 (β-catenin1), POSTN (periostin), OPG (osteoprotegerin), and OPN (osteopontin), was performed by real-time PCR. Results The inductors of osteogenic differentiation provoked greater mineralization of AVIC cultures derived from the patients with AS than that observed in control group (p=0.0003). The expression of RUNX2 and SPRY1 in non-differentiated cells was reduced compared with control cells in patients with bicuspid AV (p=0.02). After 21 days of the osteogenic induction, the expression of RUNX2 and SPRY1 increased in all three groups. At the same time, the expression of SPRY1 was lower in the group with bicuspid AV compared with tricuspid AV (p=0.007). The expression level of BMP2 did not differ between groups in unstimulated AVIC, however, it increased after osteogenic differentiation in the group of patients with tricuspid AV (p=0.017). OPN expression was higher in cells from tricuspid AV, while OPG expression was reduced in patients with both bicuspid and tricuspid AV (p&lt;0.01), No differences were found between the groups) for the remaining genes (POSTIN, CTNNB1, SOX9) before and after stimulation with an osteogenic medium. Conclusions The osteogenic potential of AVIC is increased in patients with aortic stenosis. The gene expression profile of osteogenic differentiation differs in patients with a bicuspid and tricuspid aortic valve. Damage of protective mechanisms may be a potential mechanism for accelerated valve calcification mostly in patients with tricuspid aortic valve. Acknowledgement/Funding Russian Foundation for Basic Research, project 18-015-00016

Pilose antler aqueous extract promotes the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells by stimulating the BMP-2/Smad1, 5/Runx2 signaling pathway.

Peptides from Pilose antler aqueous extract (PAAE) have been shown to stimulate the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs). However, the underlying molecular mechanisms are not well understood. Here, PAAE was isolated and purified to explore the molecular mechanisms underlying PAAE's effects on BMSCs as well as its osteoprotective effects in ovariectomized rats. Our results showed that PAAE promoted proliferation and differentiation of BMSCs to become osteoblasts by enhancing ALP activity and increasing extracellular matrix mineralization. The trabecular microarchitecture of ovariectomized rats was also found to be protected by PAAE. Quantitative reverse transcription-polymerase chain reaction (Quantitative RT-PCR) results suggest that PAAE also increased the expression of osteogenic markers including, alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), bone morphogenetic protein-2 (BMP-2), and collagen I (COL-I). Immunoblotting results indicated that PAAE upregulated the levels of BMP-2 and Runx2 and was associated with Smad1/5 phosphorylation. PAAE A at the concentration of 200 μg·mL-1 showed the strongest effect on proliferation and osteogenic differentiation of BMSCs after 48 h. Using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), we identified the molecular weight of PAAE A and found that it is less than 3000 Da and showed several significant peaks. In conclusion, PAAE activates the BMP-2/Smad1, 5/Runx2 pathway to induce osteoblastic differentiation and mineralization in BMSCs and can inhibit OVX-induced bone loss. These mechanisms are likely responsible for its therapeutic effect on postmenopausal osteoporosis.

Guhong Injection promotes fracture healing by activating Wnt/beta-catenin signaling pathway in vivo and in vitro

Guhong Injection (GHI), composed of aceglutamide and safflower aqueous extract, has been applied to the clinical treatment of orthopedic diseases, but the relevant mechanism by which GHI exerts effects on bone remodeling has not been reported. In the present study, we investigated the effects of various concentrations of GHI (2.5, 5 and 10 ml/kg) in accelerating rat tibia healing progress by observing haematoxylin and eosin (HE) stained sections, detecting the activity of bone metabolism biochemical markers such as bone morphogenetic protein-2 (BMP-2), transforming growth factor-beta (TGF-beta), osteocalcin (OC) and C-terminal crosslinking telopeptide of type Ⅰ collagen (CTX-1) in rat serum, as well as measuring the expressions of collagen I (COL-1) and collagen II (COL-2) in rat tibia. Also, we investigated the effects of different concentrations of GHI (30, 60 and 90 μl/ml) on the proliferation and differentiation of osteoblasts (OBs) through proliferating cell nuclear antigen (PCNA), alkaline phosphatase (ALP) and type I collagen (COL-1). At the same time, the expression of important factors of Wnt/beta-catenin signaling pathway including Wnt-3a, beta-catenin, disheveled-1 (Dvl-1), glycogen synthase kinases-3beta (GSK-3beta), lymphoid enhancing factor-1 (LEF-1) and axis inhibition protein-2 (Axin-2) after GHI intervention was detected by quantitative real-time PCR (q-PCR), immunohistochemistry and Western blotting. In vivo, rats of tibia fracture model treated with intraperitoneal injection (ip) of GHI had more mature fibroblasts, as well as shorter period formation of new bone. The levels of BMP-2, TGF-beta and OC in rat serum were significantly up-regulated, while the level of CTX was down-regulated. After 4 weeks of drug treatment, the level of COL-1 in the rat tibia increased, but there was no significant change in the level of COL-2. In vitro, after drug intervention, the number of OBs increased significantly, the activities of PCNA, ALP and COL-1 were enhanced. Treatment with GHI increased the mRNA and protein expression of Wnt-3a, beta-catenin, Dvl-1 and LEF-1, and decreased the expression of mRNA of Axin-2 and GSK-3beta. All results demonstrate that GHI accelerates the proliferation of OBs and shortens the recovery time of bone structure, and the Wnt/beta-catenin signaling pathway is involved in the regulation process.