Multi-modal molecular determinants of clinically relevant osteoporosis subtypes.

Due to a rapidly aging global population, osteoporosis and the associated risk of bone fractures have become a wide-spread public health problem. However, osteoporosis is very heterogeneous, and the existing standard diagnostic measure is not sufficient to accurately identify all patients at risk of osteoporotic fractures and to guide therapy. Here, we constructed the first prospective multi-omics atlas of the largest osteoporosis cohort to date (longitudinal data from 366 participants at three time points), and also implemented an explainable data-intensive analysis framework (DLSF: Deep Latent Space Fusion) for an omnigenic model based on a multi-modal approach that can capture the multi-modal molecular signatures (M3S) as explicit functional representations of hidden genotypes. Accordingly, through DLSF, we identified two subtypes of the osteoporosis population in Chinese individuals with corresponding molecular phenotypes, i.e., clinical intervention relevant subtypes (CISs), in which bone mineral density benefits response to calcium supplements in 2-year follow-up samples. Many snpGenes associated with these molecular phenotypes reveal diverse candidate biological mechanisms underlying osteoporosis, with xQTL preferences of osteoporosis and its subtypes indicating an omnigenic effect on different biological domains. Finally, these two subtypes were found to have different relevance to prior fracture and different fracture risk according to 4-year follow-up data. Thus, in clinical application, M3S could help us further develop improved diagnostic and treatment strategies for osteoporosis and identify a new composite index for fracture prediction, which were remarkably validated in an independent cohort (166 participants).

Efficacy and safety of Wuhu oral liquid in treating acute soft tissue injuries: a multicenter, randomized, double-blind, double-dummy, parallel-controlled trial.

Background: Wuhu Oral Liquid (WHOL) is a modified preparation derived from the famous Wuhu Powder, which has a long history of use in treating traumatic injuries. This preparation has anti-inflammatory and analgesic properties and accelerates recovery following acute soft tissue injuries. Aims: To evaluate the efficacy and safety of WHOL in treating acute soft tissue injury associated with qi stagnation and blood stasis syndrome and to provide a basis for applying for the protection of varieties of Chinese medicine for WHOL. Methods: This study was a randomized, controlled, double-blind, multicenter clinical trial in which Fufang Shang Tong Capsule (FFSTC) was selected as the control drug. A total of 480 subjects with acute soft tissue injury associated with qi stagnation and blood stasis syndrome were randomly divided into a test and control group in a 3:1 ratio. The duration of drug treatment was 10 days. The primary outcome was Visual Analogue Scale (VAS) score for pain (including pain at rest and pain on activity). Secondary outcomes included the disappearance time of the pain at rest and on activity; the curative effect of TCM syndrome and improvement in the individual symptoms of TCM (swelling, ecchymosis, and dysfunction); and changes in C-reactive protein (CRP) and interleukin-6 (IL-6) levels. Safety was assessed using vital signs, laboratory examinations, electrocardiograms, and physical examinations. Results: Patient compliance was satisfactory in both groups (all between 80% and 120%). After 4 days of treatment, the WHOL group was superior to the FFSTC group in decreasing the VAS scores for pain at rest (-1.88 ± 1.13 vs. -1.60 ± 0.93, p < 0.05) and on activity (-2.16 ± 1.18 vs. -1.80 ± 1.07, p < 0.05). After 7 days of treatment, the WHOL group was superior to the FFSTC group in decreasing the VAS scores for pain on activity (-3.87 ± 1.60 vs. -3.35 ± 1.30, p < 0.01) and improving swelling (cure rate: 60.4% vs. 46.2%, p < 0.05; obvious effective rate: 60.7% vs. 47.0%, p < 0.05). After 10 days of treatment, the WHOL group was superior to the FFSTC group in decreasing the levels of CRP (-0.13 ± 2.85 vs. 0.25 ± 2.09, p < 0.05) and improving the TCM syndrome (cure rate: 44.1% vs. 30.8%, p < 0.05) and swelling (cure rate: 75.6% vs. 67.5%, p < 0.01; obvious effective rate: 75.6% vs. 68.4%, p < 0.05; effective rate: 77.0% vs. 71.8%, p < 0.05). The disappearance time of pain at rest was 8 days in both groups and 9 days on activity in both groups. In addition, there was no statistical difference between the incidence of adverse events (4.5% vs. 2.6%, p > 0.05) and adverse reactions (0.3% vs. 0%, p > 0.05) between the WHOL group and the FFSTC group. No serious adverse events occurred in either group, and no subjects were withdrawn because of adverse events. Conclusion: WHOL relieves the symptoms caused by acute soft tissue injury associated with qi stagnation and blood stasis syndrome more rapidly than FFSTC, and it is effective and safe in the treatment of acute soft tissue injury. Future studies still need a larger sample size to verify its efficacy and safety. Clinical Trial Registration: https:// www.chictr.org.cn/showproj.html?proj=149531, Identifier ChiCTR2200056411.

The prevalence of osteoporosis in China, a community based cohort study of osteoporosis.

Background: Osteoporosis has already been a growing health concern worldwide. The influence of living area, lifestyle, socioeconomic, and medical conditions on the occurrence of osteoporosis in the middle-aged and elderly people in China has not been fully addressed. Methods: The study was a multicenter cross-sectional study on the middle-aged and elderly permanent residents, which gathered information of 22,081 residents from June 2015 to August 2021 in seven representative regions of China. The bone mineral density of lumbar vertebrae and hip were determined using the dual-energy X-ray absorptiometry densitometer instruments. Serum levels of bone metabolism markers were also measured. Information about education, smoking, and chronic diseases were also collected through face-to-face interviews. Age-standardized prevalence and 95% confidence intervals (CIs) of osteopenia and osteoporosis by various criteria were estimated by subgroups and overall based on the data of China 2010 census. The relationships between the osteoporosis or osteopenia and sociodemographic variables or other factors were examined using univariate linear models and multivariable multinomial logit analyses. Results: After screening, 19,848 participants (90%) were enrolled for the final analysis. The age-standardized prevalence of osteoporosis was estimated to be 33.49%(95%CI, 32.80-34.18%) in the middle-aged and elderly Chinese permanent residents, for men and women was 20.73% (95% CI, 19.58-21.87%) and 38.05% (95% CI, 37.22-38.89%), respectively. The serum concentrations of bone metabolic markers, and calcium and phosphorus metabolism were influenced by age, body mass index (BMI), gender, education level, regions, and bone mass status. Women, aged 60 or above, BMI lower than 18.5 kg/m2, low education level including middle school, primary school and no formal education as well as current regular smoking, a history of fracture were all significantly associated with a higher risk of osteoporosis and osteopenia in the middle-aged and elderly people. Conclusions: This study revealed dramatic regional differences in osteoporosis prevalence in China, and female, aged 60 or older, low BMI, low education level, current regular smoking, and a history of fracture were associated with a high risk of osteoporosis. More prevention and treatment resources should be invested into particular population exposed to these risk factors.

Osthole enhances the bone mass of senile osteoporosis and stimulates the expression of osteoprotegerin by activating ß-catenin signaling.

INTRODUCTION: Osthole has a potential therapeutic application for anti-osteoporosis. The present study verified whether osthole downregulates osteoclastogenesis via targeting OPG. METHODS: In vivo, 12-month-old male mice were utilized to evaluate the effect of osthole on bone mass. In vitro, bone marrow stem cells (BMSCs) were isolated and extracted from 3-month-old OPG-/- mice and the littermates of OPG+/+ mice. Calvaria osteoblasts were extracted from 3-day-old C57BL/6J mice or 3-day-old OPG-/- mice and the littermates of OPG+/+ mice. RESULTS: Osthole significantly increased the gene and protein levels of OPG in primary BMSCs in a dose-dependent manner. The deletion of the OPG gene did not affect ß-catenin expression. The deletion of the ß-catenin gene inhibited OPG expression in BMSCs, indicating that osthole stimulates the expression of OPG via activation of ß-catenin signaling. CONCLUSION: Osthole attenuates osteoclast formation by stimulating the activation of ß-catenin-OPG signaling and could be a potential drug for the senile osteoporosis.

Phenol glycosides extract of Fructus Ligustri Lucidi attenuated depressive-like behaviors by suppressing neuroinflammation in hypothalamus of mice.

Depression is partially caused by inflammation in central nervous system. This study investigated the ameliorative effects of phenol glycosides (PG) from Ligustrum lucidum Ait. (Oleaceae) on neuroinflammation and depressive-like behavior in mice hypothalamus as well as the molecular mechanism. Mice were administered with PG extract for 2 weeks prior to treatment with LPS. The mice treated with PG extract showed resistance to LPS-induced reduction in body weight and LPS-induced depressive-like behaviors shown by sucrose preference, tail suspension test, forced swimming test and open field test. LPS-induced activation of microglial cells and elevation in protein expression of inflammatory cytokines including IL-1ß, RANTES and MCP-1 in hypothalamus of mice were abrogated by pre-treatment with PG extract. This extract down-regulated expression of TLR4, MyD88, NLRP3, renin and angiotensin II and decreased proportional area of Iba-1+ microglias in hypothalamus. Pre-treatment with PG extract inhibited LPS-triggered activation of CaSR/Gα11 signaling, stimulated 1-OHase expression in hypothalamus, and enhanced circulating 1,25(OH)2 D3 level. Overall, pre-treatment with PG extract ameliorated LPS-induced depressive-like behaviors by repressing neuroinflammation in mice hypothalamus which was attributed to its suppression on activation of microglia and production of inflammatory cytokines via acting on TLR4 pathway, CaSR and RAS cascade associated with improving vitamin D metabolism.

Daidzein promotes proliferation and differentiation in osteoblastic OCT1 cells via activation of the BMP-2/Smads pathway.

Daidzein, the most widely studied soy phytoestrogen, is not only a potential antiosteoporosis agent owing to its possible osteogenic activity, but also shows anticancer activity. However, the mechanisms through which daidzein affects osteoblast function have not been well understood. Here, we show that daidzein stimulated cell proliferation and differentiation of osteoblasts, demonstrated by upregulation of XTT activity, enhancement of alkaline phosphatase (ALP) activity, and upregulation of osteoblast-specific marker genes, including Runt-related transcription factor 2 (Runx2) and Smad1, as well as up-regulation of Runx2 and Smad1 protein expression. To determine the mechanisms underlying daidzein's effects on osteoblast differentiation, we first tested the role of daidzein in bone morphogenetic protein (BMP)-2 gene expression in OCT1 cells, and found that it significantly upregulated the expression of BMP-2. Furthermore, it significantly enhanced the phosphorylated protein level of Smad1/5/8and protein expression of Osterix (Osx, a direct target gene of BMP signaling) and increased the activity of BMP signaling reporter (12xSBE-OC-Luc). Finally, we demonstrated that daidzein stimulated Col I, Runx2, and ALP expression, while these effects were significantly blocked by the BMP signaling inhibitor noggin. Thus, our data indicate that daidzein acts through stimulating the activation of BMP-2/Smads pathway to promote osteoblast proliferation and differentiation.

[Short-segment posterior pedicle screw combined with vertebral arch bone grafting for thoracolumbar burst fractures].

OBJECTIVE: To analyze the clinical effects of short-segment posterior pedicle screw combined with transpedicle vertebral bone grafting in treating thoracolumbar burst fractures. METHODS: From March 2008 to March 2013, 62 patients with thoracolumbar burst fractures were treated with short-segment posterior pedicle screw combined with transpedicle vertebral bone grafting. Including 40 males and 22 females, the age from 17 to 65 years old with an average of 38 years. According to AO classification, 34 cases were type A3.1, 7 cases were type A3.2 and 21 cases were type A3.3. Load-sharing scores were from 4 to 6 points with an average of 5.4 points. According to ASIA grade, 2 cases were grade C, 5 cases were grade D and 55 cases were grade E. Preoperative, postoperative at 3 d and final follow-up, the Cobb angle, the relative height of anterior vertebral body and the encroachment rate of spinal canal were measured by X-ray films and computed tomography (CT) scan, meanwhile, the information of bone healing and spinal nerves recovery were observed. RESULTS: All patients were followed up from 11 to 14 months with an average of 12.2 months. The duration of removing internal fixation were from 9 to 13 months (averaged, 11.5 months). One suffered from infection and was cured by debridement. Two cases had mild pain of back. At 6 months after operation, according to ASIA grade to evaluate never function, 1 case was grade C, 3 cases were grade D and 58 cases were grade E. X-ray and CT showed the fractures obtained good union at final follow-up. The Cobb angle, the relative height of anterior vertebral body and the encroachment rate of spinal canal had obviously improved at 3 days after operation (P<0.05); but there was no significant differences between postoperative at 3 d and final follow-up (P>0.05). CONCLUSION: Short-segment posterior pedicle screw combined with transpedicle vertebral bone grafting is an effective method to treat thoracolumbar burst fractures. It can reduce the loss of postoperative correction and prevent the internal fixation failure.

Icariin Augments Bone Formation and Reverses the Phenotypes of Osteoprotegerin-Deficient Mice through the Activation of Wnt/ ß -Catenin-BMP Signaling.

Icariin has been mostly reported to enhance bone fracture healing and treat postmenopausal osteoporosis in ovariectomized animal model. As another novel animal model of osteoporosis, there is few publication about the effect of Icariin on osteoprotegerin-deficient mice. Therefore, the goal of this study is to find the effect on bone formation and underlying mechanisms of Icariin in osteoprotegerin (OPG) knockout (KO) mice. We found that Icariin significantly stimulated new bone formation after local injection over the surface of calvaria at the dose of 5 mg/kg per day. With this dose, Icariin was also capable of significantly reversing OPG-deficient-induced bone loss and bone strength reduction. Real-time PCR analysis showed that Icariin significantly upregulated the expression of BMP2, BMP4, RUNX2, OC, Wnt1, and Wnt3a in OPG KO mice. Icariin also significantly increased the expression of AXIN2, DKK1, TCF1, and LEF1, which are the direct target genes of ß -catenin signaling. The in vitro studies showed that Icariin induced osteoblast differentiation through the activation of Wnt/ ß -catenin-BMP signaling by in vitro deletion of the ß -catenin gene using ß -catenin(fx/fx) mice. Together, our findings demonstrate that Icariin significantly reverses the phenotypes of OPG-deficient mice through the activation of Wnt/ ß -catenin-BMP signaling.

Golden plaster for pain therapy in patients with knee osteoarthritis: study protocol for a multicenter randomized, double-blind, placebo-controlled trial.

BACKGROUND: Osteoarthritis is a relatively common musculoskeletal disorder that increases in prevalence with age. Worldwide, knee osteoarthritis is one of the leading causes of disability, particularly in the elderly. In numerous trials of agents for long-term pain therapy, no well-established and replicable results have been achieved. Complementary and alternative medical approaches have been employed for thousands of years to relieve knee osteoarthritis pain. Among herbal medicines, the golden plaster is the preferred and most commonlyused method in China to reduce pain in patients with knee osteoarthritis, as it causes few adverse effects. The purpose of this study will be to evaluate the efficacy and safety of golden plaster on pain in patients with knee osteoarthritis. METHODS/DESIGN: This study will be a multicenter randomized, double-blind, placebo-controlled trial. A total of 320 participants aged 45 to 79 years with knee osteoarthritis, whose scores on a visual analog scale (VAS) are more than 20 mm,will be randomly allocated into a treatment group and a control group. A golden plaster will be administered externally to participants in the treatment group for 2 weeks, while the control group will receive a placebo plaster externally for 2 weeks. Follow-up will be at regular intervals during a 4-week period with a VAS score for pain, quality of life, and complications. DISCUSSION: This study will be a methodologically sound randomized controlled trial to assess pain relief after the intervention of golden plaster, compared to a placebo intervention in patients with knee osteoarthritis. TRIAL REGISTRATION: ClinicalTrials.gov identifier: ChiCTR-TRC-13003418.

Chondrocyte-specific inhibition of ß-catenin signaling leads to dysplasia of the caudal vertebrae in mice.

STUDY DESIGN: To inhibit ß-catenin specifically signaling in chondrocytes Col2-ICAT transgenic mice were generated. Anomalies in caudal vertebrae were detected during embryonic and postnatal stages of Col2-ICAT transgenic mice. OBJECTIVE: To determine the role of canonical ß-catenin signaling in caudal vertebral development. SUMMARY OF BACKGROUND DATA: ß-catenin signaling plays a critical role in skeletal development. Col2-ICAT transgenic mice were generated to selectively block ß-catenin signaling by overexpression of the ICAT gene in chondrocytes. METHODS: Tails of E16.5 transgenic embryos and adult Col2-ICAT transgenic mice and their wild-type littermates were collected and analyzed. Skeletal preparation, 3-dimensional micro-computed tomographic and histological analyses were performed to evaluate changes in the structure of caudal vertebrae. Bromodeoxyuridine labeling was performed to evaluate changes in chondrocyte proliferation in caudal vertebrae. RESULTS: Skeletal preparation and 3-dimensional micro-computed tomographic analyses revealed bone deformation and angulated deformities in tail tissue in Col2-ICAT transgenic mice. Histological studies revealed abnormal bone development and dysplastic caudal vertebrae in Col2-ICAT transgenic mice. Inhibition of ß-catenin signaling in cartilage resulted in vertebral dysplasia leading to aberrant resegmenting process. Thus, 2 poorly developed sclerotomes failed to fuse to form a complete vertebrae. BrdU labeling revealed a decreased chondrocyte proliferation in both cartilageous templates of transgenic embryos and the growth plate of adult Col2-ICAT transgenic mice. CONCLUSION: Wnt/ß-catenin signaling plays an important role in vertebral development. Inhibition of ß-catenin signaling in chondrocytes results in caudal vertebra deformity in mice, which may occur as early as in the stage of sclerotome formation. LEVEL OF EVIDENCE: N/A.

[Experimental study on lumbar intervetebral disc degeneration model with kidney deficiency by ovariectomizing].

OBJECTIVE: To observe effects of removing arms and ovarian on lumbar intervertebral disc and vertebral bone mineral density (BMD) by establishing rat model of lumbar intervetebral disc degeneration (IDD) with kidney deficiency, and to explore internal mechanism of disc degeneration, relationship between disc degeneration and osteoporosis. METHODS: Thirty Sprague-Dawley female rats aged one month were randomly divided into control group, lumbar IDD group and lumbar IDD with kidney deficiency group (combined group), 10 rats in each group. Lumbar IDD group removed double arms, lumbar IDD with kidney deficiency group removed double arms after 3 months, both ovaries were removed. Vertebral bone mineral density were observed by Micro-CT scan; morphological changes were tested by safranine O-fast green staining; II, X collagen protein expression in the intervertebral disc were obsevered by immunohistochemistry; extracellular matrix gene expression were obsevered by real-time polymerase chain reaction (RT-PCR), in order to evaluate the effects of removed of forelimbs and double ovarian on degeneration and vertebral bone mineral density of intervertebral disc. RESULTS: Micro-CT scan showed osteoporosis in kidney deficiency group was obviously worse than other two groups; safranine O-fast green staining showed that intervertebral space became narrowed, intervertebral disc tissue degenerated obviously, chondral palte was underdeveloped in kidney deficiency group; immunohistochemistry showed that X collagen expression increased, type II collagen expression decreased in kidney deficiency group; RT-PCR showed that type II collagen expression in lumbar IDD group and kidney deficiency group was lower than control group, and had statistical meaning among three groups (P=0.000, P=0.000); Age 1 in lumbar IDD group and kidney deficiency group was lower than control group, and had statistical meaning among three groups (P=0.000, P= 0.000); while type X collagen expression was higher than control group, but no significant meaning; MMP-13 in lumbar IDD group and kidney deficiency group was higher than control group, with significant meaning compared among three groups (P= 0.000, P=0.000); aggrecanase-2 in lumbar IDD group and kidney deficiency group was higher than control group, with significant meaning compared among three groups (P=0.006, P=0.008). CONCLUSION: Rats model of lumbar disc degeneration established by removed forelimbs and ovariectomized can occure "bone like"--osteoporosis, which is similar with clinical kidney lumbar disc degeneration in tissue morphology, molecular cell biology expression.

Oleanolic acid exerts an osteoprotective effect in ovariectomy-induced osteoporotic rats and stimulates the osteoblastic differentiation of bone mesenchymal stem cells in vitro.

OBJECTIVE: Oleanolic acid (OA) and its glycosides have been reported to prevent bone loss by inhibiting the formation of osteoclasts. However, because bone formation and resorption are balanced processes in bone metabolism, no studies have described the effect of OA on osteogenesis. The aim of the present study was to evaluate the osteoprotective effect of OA in rats with ovariectomy (OVX)-induced osteoporosis and to search for the molecular targets of OA in bone mesenchymal stem cells (bMSCs). METHODS: Two-month-old female mice that underwent OVX were treated with OA (20 mg/kg a day). After 2 weeks and after 3 months, bone mass was evaluated by micro-CT, morphometry, and immunohistochemical detection. In addition, the expression of 256 genes was measured via microarray and confirmed by real-time reverse transcription-polymerase chain reaction. The effects of OA on the activities of bMSCs were also observed in vitro using alkaline phosphatase and cell proliferation assays. RESULTS: Micro-CT displayed only a tendency for bone loss at 2 weeks but a decrease in bone mass at 3 months after OVX. OA treatment increased osteoblast number, increasing osteocalcin and runt-related protein 2 protein levels in vivo and facilitating the osteoblastic differentiation of bMSCs in vitro at doses of 10(-6) and 10(-5) M. Gene expression profile analysis revealed that OVX caused a marked dysregulation of gene expression, especially at 2 weeks, some of which was rescued by OA. Few of these genes overlapped, but their functions were involved in the Notch signaling pathway between two phases of the osteoporotic process. CONCLUSIONS: OA exerts an osteoprotective effect in OVX-induced osteoporotic rats and stimulates the osteoblastic differentiation of bMSCs in vitro. The molecular mechanism of this effect might be related to the Notch signaling pathway and requires further investigation.

Classic yin and yang tonic formula for osteopenia: study protocol for a randomized controlled trial.

BACKGROUND: Osteoporosis is a growing worldwide problem, with the greatest burden resulting from fractures. Nevertheless, the majority of fractures in adults occur in those with "osteopenia" (bone mineral density (BMD) only moderately lower than young normal individuals). Since long-term drug therapy is an expensive option with uncertain consequences and side effects, natural herbal therapy offers an attractive alternative. The purpose of this study is to evaluate the effect on BMD and safety of the Classic Yin and Yang Tonic Formula for treatment of osteopenia and to investigate the mechanism by which this efficacy is achieved. METHODS/DESIGN: We propose a multicenter double-blind randomized placebo-controlled trial to evaluate the efficacy and safety of the Classic Yin and Yang Tonic Formula for the treatment of osteopenia. Participants aged 55 to 75 with low bone mineral density (T-score between -1 and -2.5) and kidney deficiency in TCM will be included and randomly allocated into two groups: treatment group and control group. Participants in the treatment group will be treated with Classic Yin and Yang Tonic Granule, while the controlled group will receive placebo. Primary outcome measure will be BMD of the lumbar spine and proximal femur using dual-energy X-ray absorptiometry. Secondary outcomes will include pain intensity measured with visual analogue scales, quality of life, serum markers of bone metabolism, indices of Neuro-endocrino-immune network and safety. DISCUSSION: If the Classic Yin and Yang Tonic Formula can increase bone mass without adverse effects, it may be a novel strategy for the treatment of osteoporosis. Furthermore, the mechanism of the Chinese medical formula for osteoporosis will be partially elucidated. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov, NCT01271647.

The expression of osteoprotegerin is required for maintaining the intervertebral disc endplate of aged mice.

OBJECTIVE: Human chondrocytes and annulus fibrosus cells of intervertebral disc (IVD) express osteoprotegerin (OPG), but the effect of OPG on the pathogenesis of IVD degeneration remains unknown. Here we assessed the phenotype change of IVD in OPG(-/-) mice. METHODS: The IVDs from 12-, 20-, and 28-week-old OPG(-/-) mice and WT controls were subjected to histologic analyses including TRAP staining for osteoclasts, immunostaining for OPG and type I collagen protein expression, and TUNEL staining for apoptosis. The IVD tissues were also subjected to real time RT-PCR for mRNA expression of genes for osteoblast-osterix, ALP, and osteocalcin; for osteoclasts-trap, rank, mmp9 and cathepsin K, and for chondrocytes-aggrecan, mmp13 and Col10. RESULTS: OPG protein expresses at the cells of endplate cartilage and annulus fibrosis in IVDs of WT mice. Compared to WT mice, OPG(-/-) mice developed aging related cartilage loss and bony tissue appearance at the endplate. Stating from 20 weeks of age, IVDs from OPG(-/-) mice expressed significantly increased mmp13 and Col10 levels, which is associated with increased osteoblast number and elevated expression of osteoblast marker genes. Furthermore, TRAP+ osteoclasts were presented in the endplate cartilage of OPG(-/-) mice. These osteoclasts localized adjacently to and erosion into the cartilage. Increased expression of RANK, mmp9 and cathepsin k was detected in OPG(-/-) IVDs. CONCLUSIONS: OPG at IVD plays an important role for maintaining the integrity of endplate cartilage during aging by preventing endplate cartilage from osteoclast-mediated resorption.

Psoralen stimulates osteoblast differentiation through activation of BMP signaling.

Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. In order to improve the treatment of osteoporosis, identification of anabolic and orally available agents with minimal side effects is highly desirable. Psoralen is a coumarin-like derivative extracted from Chinese herbs, which have been used to treat bone diseases for thousands of years. However, the role of Psoralen in osteoblast function and the underlying molecular mechanisms remain poorly understood. In this study, we found that Psoralen promoted osteoblast differentiation in primary mouse calvarial osteoblasts in a dose-dependent manner, demonstrated by up-regulation of expressions of osteoblast-specific marker genes including type I collagen, osteocalcin and bone sialoprotein and enhancement of alkaline phosphatase activity. We further demonstrated that Psoralen up-regulated the expression of Bmp2 and Bmp4 genes, increased the protein level of phospho-Smad1/5/8, and activated BMP reporter (12xSBE-OC-Luc) activity in a dose-dependent manner, as well as enhanced the expression of Osx, the direct target gene of BMP signaling. Deletion of the Bmp2 and Bmp4 genes abolished the stimulatory effect of Psoralen on the expression of osteoblast marker genes, such as Col1, Alp, Oc and Bsp. Our results suggest that Psoralen acts through the activation of BMP signaling to promote osteoblast differentiation and demonstrate that Psoralen could be a potential anabolic agent to treat patients with bone loss-associated diseases such as osteoporosis.

Osthole stimulates osteoblast differentiation and bone formation by activation of beta-catenin-BMP signaling.

Osteoporosis is defined as reduced bone mineral density with a high risk of fragile fracture. Current available treatment regimens include antiresorptive drugs such as estrogen receptor analogues and bisphosphates and anabolic agents such as parathyroid hormone (PTH). However, neither option is completely satisfactory because of adverse effects. It is thus highly desirable to identify novel anabolic agents to improve future osteoporosis treatment. Osthole, a coumarin-like derivative extracted from Chinese herbs, has been shown to stimulate osteoblast proliferation and differentiation, but its effect on bone formation in vivo and underlying mechanism remain unknown. In this study, we found that local injection of Osthole significantly increased new bone formation on the surface of mouse calvaria. Ovariectomy caused evident bone loss in rats, whereas Osthole largely prevented such loss, as shown by improved bone microarchitecture, histomorphometric parameters, and biomechanical properties. In vitro studies demonstrated that Osthole activated Wnt/beta-catenin signaling, increased Bmp2 expression, and stimulated osteoblast differentiation. Targeted deletion of the beta-catenin and Bmp2 genes abolished the stimulatory effect of Osthole on osteoblast differentiation. Since deletion of the Bmp2 gene did not affect Osthole-induced beta-catenin expression and the deletion of the beta-catenin gene inhibited Osthole-regulated Bmp2 expression in osteoblasts, we propose that Osthole acts through beta-catenin-BMP signaling to promote osteoblast differentiation. Our findings demonstrate that Osthole could be a potential anabolic agent to stimulate bone formation and prevent estrogen deficiency-induced bone loss.