Periostin Promotes the Proliferation, Differentiation and Mineralization of Osteoblasts from Ovariectomized Rats.

Perimenopausal period causes a significant amount of bone loss, which results in primary osteoporosis (OP). The Periostin (Postn) may play important roles in the pathogenesis of OP after ovariectomized (OVX) rats. To identify the roles of Postn in the bone marrow mesenchymal stem cell derived osteoblasts (BMSC-OB) in OVX rats, we investigated the expression of Wnt/ß-catenin signaling pathways in BMSC-OB and the effects of Postn on bone formation by development of BMSC-OB cultures. Twenty-four female Sprague-Dawley rats at 6 months were randomized into 3 groups: sham-operated (SHAM) group, OVX group and OVX+Postn group. The rats were killed after 3 months, and their bilateral femora and tibiae were collected for BMSC-OB culture, Micro-CT Analysis, Bone Histomorphometric Measurement, Transmission Electron Microscopy and Immunohistochemistry Staining. The dose/time-dependent effects of Postn on the proliferation, differentiation and mineralization of BMSC-OB and the expression of osteoblastic markers were measured in in vitro experiments. We found increased Postn increased bone mass, promoted bone formation of trabeculae, Wnt signaling and the osteogenic activity in osteoblasts in sublesional femur. Postn have the function to enhance cell proliferation, differentiation and mineralization at a proper concentration and incubation time. Interestingly, in BMSC-OB from OVX rats treated with the different dose of Postn, the osteoblastic markers expression and Wnt/ß-catenin signaling pathways were significantly promoted. The direct effect of Postn may lead to inhibit excessive bone resorption and increase bone formation through the Wnt/ß-catenin signaling pathways after OVX. Postn may play a very important role in the pathogenesis of OP after OVX.

Comparison of Direct Pars Repair Techniques for Spondylolysis in Young Patients: Pedicle Screw Hook System versus Pedicle Screw Rod.

Background: Lumbar spondylolysis (LS) poses a potential threat, and there is a need to evaluate and compare the effectiveness of direct pars repair techniques. Objective: To assess and compare the clinical and radiographic outcomes of direct pars repair techniques using the pedicle screw hook system (PSHS) and the pedicle screw rod system (PSRS) in young symptomatic patients with lumbar spondylolysis. Methods: A retrospective study was conducted to compare clinical and radiological data in young symptomatic LS patients after surgery. Records of 45 post-surgery LS patients with a minimum 24-month follow-up (January 2014 to June 2019) were reviewed. A total of 26 patients underwent PSHS, and 19 had PSRS. Treatment outcomes were analyzed using the visual analog pain scale (VAS), Oswestry disability index (ODI), MacNab criteria, lumbar fusion status, and Pfirrmann grading standards. Patient baseline characteristics were also compared between the two groups. Results: No disc degeneration was observed in either PSHS or PSRS groups at 24 months postoperatively, according to the Pfirrmann grading scale. The PSRS group outperformed the PSHS group in operative time, intraoperative blood loss, postoperative drainage, length of hospital stays, ODI, VAS values at 3 months postoperatively, and fusion status at 6 months postoperatively. No notable differences were observed in other parameters during the 24-month follow-up period, and no significant surgical complications were recorded. Conclusions: Direct pars repair techniques using PSHS and PSRS yielded satisfactory clinical and radiographic results in young patients with symptomatic LS. PSRS, compared to PSHS, demonstrated greater effectiveness in young individuals with LS and promoted early recovery.

Combined use of tranexamic acid and rivaroxaban in posterior lumbar interbody fusion safely reduces blood loss and transfusion rates without increasing the risk of thrombosis-a prospective, stratified, randomized, controlled trial.

PURPOSE: This prospective, stratified, randomized, single-blind, placebo-controlled multicentre study investigated the safety and effectiveness of reducing blood loss and preventing venous thromboembolism (VTE) during posterior lumbar interbody fusion (PLIF) in patients with stenosis or spondylolisthesis using the combination of tranexamic acid (TXA) and rivaroxaban. METHODS: The Autar score was evaluated in patients after admission. Patients with an Autar score ≤ 10 were randomized to group A or B. Group A was the placebo-controlled group. Patients in group B were treated with 1 g TXA via intravenous injection and 1 g TXA for external use. Patients with an Autar score > 10 were randomized to group C or D. Patients in group C were treated with 10-mg rivaroxaban qd for 35 days after surgery. Patients in group D received the same treatment as those in group B intra-operatively and as those in group C post-operatively. RESULTS: A total of 599 patients from eight hospitals participated in this clinical trial. The total blood loss, intra-operative blood loss, and drainage volume were reduced by the administration of TXA (group A vs group B, P < 0.01; group C vs group D, P < 0.01), and the blood transfusion rate was also decreased (group A vs group B, P < 0.01; group C vs group D, P < 0.01). There were no significant differences (P > 0.05) in the VTE incidence rates among group A and group B. In patients with high-risk thrombosis, the number of patients with VTE was only three and seven after the application of rivaroxaban. Epidural haematoma was not discovered in any patients in our trial. CONCLUSION: The combined application of tranexamic acid and rivaroxaban significantly reduced the amount of blood loss and the transfusion rate during PLIF surgery and avoided an increase in the probability of thrombosis and the occurrence of epidural haematoma. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: ChiCTR-1800016430 2018-06-01.

Decreased Synovial Fluid α-Melanocyte-Stimulating-Hormone (α-MSH) Levels Reflect Disease Severity in Patients with Posttraumatic Ankle Osteoarthritis.

BACKGROUND: α-Melanocyte-stimulating hormone (α-MSH), an endogenous melanocortin peptide, has been demonstrated to have anti-inflammation effects and protect against cartilage damage. Objective In this study, we aimed to investigate whether α-MSH in ankle joint synovial fluid is associated with the disease severity of posttraumatic ankle osteoarthritis (PTAOA). METHODS: 66 PTAOA patients undergoing ankle arthroscopical debridement or ankle joint replacement were enrolled in the study. Synovial fluid α-MSH concentrations were explored by a special radioimmunoassay method. Cartilage degradation biomarkers such as collagen type II (CTX-II), aggrecan-1 (AGG-1), as well as inflammatory markers, interleukin-6 (IL-6) and matrix metalloproteinases-3 (MMP-3) in the synovial fluid were determined by enzyme-linked immunosorbent assay (ELISA). The symptomatic and functional severity was evaluated using Teeny-Wiss scoring and AOFAS ankle-hindfoot rating scale. The radiographic progression of PTAOA was identified according to the modified ankle osteoarthritis Kellgren-Lawrence (KL) grading system. The modified Mankin score was used for assessing the histopathological severity for cartilage lesions. Receiver operating characteristic (ROC) curve was conducted and the area under curve (AUC) was used to the evaluate the diagnostic value of α-MSH levels for the prediction of the modified K-L grading by comparing with other biomarkers examined. RESULTS: α-MSH levels in synovial fluid showed a negative correlation with, modified ankle K-L grading, Mankin scores, and degradation biomarkers CTX-II and AGG-1, as well as inflammation markers IL-6 and MMP-3. In addition, α-MSH levels were also positively associated with Teeny-Wiss scoring and AOFAS ankle-hindfoot scores. The AUC area of α-MSH was similar to CTX-II, AGG-1, IL-6, and MMP-3. CONCLUSIONS: Synovial fluid α-MSH levels showed an independent and negative correlation with disease severity in patients with PTAOA. Application of α-MSH locally may serve as a potential adjuvant therapy for delaying the process of PTAOA.

Dimethyl fumarate inhibits the expression and function of hypoxia-inducible factor-1α (HIF-1α).

Osteocyte hypoxia has been induced by skeletal unloading and fracture. Hypoxia-dependent regulation of gene expression is mediated by hypoxia-sensitive transcription factors such as hypoxia-inducible factor-1α (HIF-1α). Dimethyl fumarate (DMF) is a recently approved first-line therapy for multiple sclerosis. However, the role of DMF in regulating HIF-1α expression and function has not been evaluated. In this study, we found that DMF inhibited hypoxia-induced expression of HIF-1α and its target genes such as interleukin 8 (IL-8) and vascular endothelial growth factor (VEGF) in MC3T3 E1 cells. Mechanistically, DMF promoted HIF-1α degradation in a proteasome-dependent but von Hippel-Lindau (VHL) protein-independent manner. Importantly, we found that DMF disrupted the interaction between HIF-1α and its chaperone heat shock protein 90 (Hsp90) but promoted the interaction between HIF-1α and the receptor of activated protein kinase C (RACK1). These data suggest that DMF might promote degradation of HIF-1α by affecting its folding and maturation. Based on these observations, we conclude that DMF is a novel inhibitor of HIF-1α.

IRTKS promotes osteogenic differentiation by inhibiting PTEN phosphorylation.

Insulin stimulates osteoblast proliferation and differentiation as an anabolic agent in bone. Insulin Receptor Tyrosine Kinase Substrate (IRTKS) is involved in insulin signaling as an adapter for insulin receptors (IR). Here, we showed that IRTKS levels were significantly decreased in bone marrow mesenchymal stem cells (BMSCs) derived from the bone marrow of patients with osteoporosis. Based on relevant experiments, we observed that IRTKS promoted the proliferation, migration, and osteoblast differentiation of BMSCs and MC3T3-E1 cells. In addition, we identified a Phosphatase and Tensin homolog deleted on chromosome 10 (PTEN) as a potential active substrate of IRTKS. We demonstrated a direct interaction between IRTKS and PTEN using co-immunoprecipitation. Subsequently, we confirmed that the SH3 domain of IRTKS directly binds to the C-terminal tail of PTEN. Further experimental results demonstrated that PTEN attenuated the promoting effects of IRTKS on the proliferation, migration, and osteoblast differentiation of BMSCs and MC3T3-E1 cells. In conclusion, this study suggests that IRTKS contributes to osteogenic differentiation by inhibiting PTEN phosphorylation and provides a potential therapeutic target for osteoporosis patients.

Ortho-silicic Acid Prevents Glucocorticoid-Induced Femoral Head Necrosis by Promoting Akt Phosphorylation to Inhibit Endoplasmic Reticulum Stress-Mediated Apoptosis and Enhance Angiogenesis and Osteogenesis.

Glucocorticoid-induced osteonecrosis of the femoral head (SONFH) is the most prevalent form of secondary osteonecrosis affecting the femoral head. Glucocorticoids can cause damage to both vascular endothelial cells and osteoblasts. Previous studies have demonstrated that silicon can improve the resistance of vascular endothelial cells to oxidative stress and positively impact bone health. However, the impact of silicon on SONFH has yet to be investigated. We examined the influence of ortho-silicic acid (OSA, Si(OH)4) on the apoptosis and proliferation of vascular endothelial cells after glucocorticoid induction. Additionally, we evaluated the expression of apoptosis-related genes such as cleaved-caspase-3, Bcl-2 and Bax. The impact of glucocorticoids and OSA on the function of vascular endothelial cells was evaluated through wound healing, transwell and angiogenesis assays. Osteogenic function was subsequently evaluated through alizarin red staining, alkaline phosphatase staining and expression levels of osteogenic genes like RUNX2 and ALP. Moreover, we investigated the potential role of OSA in vivo using the SONFH animal model. At concentrations below 100 µM, OSA exhibits no toxicity on vascular endothelial cells and effectively reverses glucocorticoid-induced apoptosis in these cells. OSA increases the resilience of vascular endothelial cells against oxidative stress and enhances osteoblast differentiation. Our study revealed that glucocorticoids activate endoplasmic reticulum stress, a process that mediates the apoptosis of vascular endothelial cells. OSA ameliorated the endoplasmic reticulum stress associated with glucocorticoids through the increased expression of p-Akt levels. In vivo, OSA treatment effectively improved SONFH by enhancing vascular endothelial cell function and promoting osteogenic differentiation. OSA counteracted the adverse effects of glucocorticoids both in vitro and in vivo, demonstrating a beneficial therapeutic effect on SONFH.

Cervical curvature, spinal cord MRIT2 signal, and occupying ratio impact surgical approach selection in patients with ossification of the posterior longitudinal ligament.

OBJECTIVE: Factors impacting surgical options and outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) were explored. METHODS: A retrospective analysis was conducted of 127 eligible cervical OPLL patients (61 males, 66 females) aged 41-70 years (mean 55.2 years) selected from 152 total OPLL patients treated from 2002 to 2006, with 5-10-year (mean 6.8 years) follow-up. Patients underwent anterior subtotal corpectomy with ossification ligament resection (anterior surgery, n = 68) or posterior cervical double-door laminoplasty (posterior surgery, n = 59). Radiographic assessments of cervical curvature, T2-weighted MRI (MRIT2) signal, and OPLL occupying ratio were correlated with surgical strategy before surgery and at 1, 5 weeks, and 5 years. RESULTS: Lordosis increased following anterior surgery, though kyphosis improved by 10.3 %. The canal stenosis occupying ratio was >50 %, and short-term improvement following anterior surgery was significantly higher than posterior surgery (P > 0.0001). Superior neurological function was observed in patients with unchanged versus high spinal MRIT2 signals (P = 0.0434). No significant differences were observed in short-term outcomes between anterior and posterior surgeries in high spinal MRIT2 signal patients, but anterior surgery produced significantly better long-term outcomes at 1 week (P = 0.7564) and 1 year (P = 0.0071). Complications occurred in five anterior and three posterior surgeries. CONCLUSION: Preoperative assessment of cervical curvature, MRIT2 signal, and occupying ratio can be used to guide clinical surgical approach selection to potentially produce better long-term outcomes in patients with OPLL.

VK2 Promotes Osteogenic Differentiation of BMSCs against High Glucose Exposure via Modulation of Intracellular Oxidative Stress.

INTRODUCTION: Diabetic osteoporosis (DOP) has gradually gained public attention. The clinical manifestations of DOP include bone mass loss, bone microstructural damage, and increased bone fragility.

Ortho-silicic Acid Plays a Protective Role in Glucocorticoid-Induced Osteoporosis via the Akt/Bad Signal Pathway In Vitro and In Vivo.

Glucocorticoid-induced osteoporosis (GIOP) has been the most common form of secondary osteoporosis. Glucocorticoids (GCs) can induce osteocyte and osteoblast apoptosis. Plenty of research has verified that silicon intake would positively affect bone. However, the effects of silicon on GIOP are not investigated. In this study, we assessed the impact of ortho-silicic acid (OSA) on Dex-induced apoptosis of osteocytes by cell apoptosis assays. The apoptosis-related genes, cleaved-caspase-3, Bcl-2, and Bax, were detected by western blotting. Then, we evaluated the possible role of OSA on osteogenesis and osteoclastogenesis with Dex using Alizarin red staining and tartrate-resistant acid phosphatase (TRAP) staining. We also detected the related genes by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting. We then established the GIOP mouse model to evaluate the potential role of OSA in vivo. We found that OSA showed no cytotoxic on osteocytes below 50 µM and prevented MLO-Y4 from Dex-induced apoptosis. We also found that OSA promoted osteogenesis and inhibited osteoclastogenesis with Dex. OSA had a protective effect on GIOP mice via the Akt signal pathway in vivo. In the end, we verified the Akt/Bad signal pathway in vitro, which showed the same results. Our finding demonstrated that OSA could protect osteocytes from apoptosis induced by GCs both in vitro and in vivo. Also, it promoted osteogenesis and inhibited osteoclastogenesis with the exitance of Dex. In conclusion, OSA has the potential value as a therapeutic agent for GIOP.

Combined Use of Tranexamic Acid and Rivaroxaban in Posterior/Transforaminal Lumbar Interbody Fusion Surgeries Safely Reduces Blood Loss and Incidence of Thrombosis: Evidence From a Prospective, Randomized, Double-Blind, Placebo-Controlled Study.

STUDY DESIGN: A prospective, randomized, double-blind, placebo-controlled study. OBJECTIVES: There are few studies examining the balance between preventing venous thrombus embolism (VTE) and reducing blood loss in posterior/transforaminal lumbar interbody fusion (PLIF/TLIF) surgeries. This study aimed to evaluate the efficacy and safety of the combine application of TXA and rivaroxaban in patients undergoing PLIF/TLIF and explore relevant factors related to blood loss and VTE. METHODS: Patients in group A which was the control group received 0.9% NaCl solution intravenously. Group B was treated by an intravenous injection of 2 g tranexamic acid (TXA) and the local use of 1 g intraoperatively. Group C was treated the same as group B intraoperatively, and they received 10 mg rivaroxaban qd treatment postoperatively. Eligible patients with an Autar score ≤ 10 were randomly assigned to group A or group B. Patients with an Autar score >10 were allocated into group C. RESULTS: The intraoperative blood loss and postoperative drainage were lower in groups B and C than in group A (P < .001). The blood transfusion rate in group B was lower than that in group A (P < .001), while the incidence of VTE in group C was lower (P < .001). Four factors were found to be positively correlated with obvious total blood loss (P < .05). The data showed that 5 factors were correlated with the development of a thrombus (P < .1). CONCLUSIONS: The combination of TXA and rivaroxaban in PLIF/TLIF patients is safe and effective in reducing D-dimer levels associated with VTE and reducing blood loss.

Long non-coding RNA KCNQ1OT1 alleviates postmenopausal osteoporosis by modulating miR-421-3p/mTOR axis.

The prevention and treatment of postmenopausal osteoporosis (PMOP) is a significant public health issue, and non-coding RNAs are of vital importance in this process. In this study, we find that the long non-coding RNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (lncRNA KCNQ1OT1) can alleviate the ovariectomy-induced (OVX) PMOP in vivo. We determined that over-expression of KCNQ1OT1 could enhance functions of MC3T3-E1 cells, whereas an opposite trend was observed when KCNQ1OT1 was knocked down. Subsequently, miR-421-3p targeting KCNQ1OT1 was detected through a database search, and RNA fluorescent in situ hybridization, RNA immunoprecipitation, dual luciferase reporter assays all verified this relationship. Notably, KCNQ1OT1 stifled the miR-421-3p expression. The inhibition of proliferation, migration, and osteogenic differentiation caused by KCNQ1OT1 knock-down were reversed by an miR-421-3p inhibitor, further confirming the above findings. We verified that miR-421-3p specifically targeted the mammalian target of rapamycin (mTOR), and miR-421-3p inhibitor could reverse the negative effects of small interfering RNA of mTOR (si-mTOR) on MC3T3-E1 cells. Finally, osteoblasts isolated and cultured from OVX mice model and control mice also confirmed the observed trend. In combination, results mentioned above reveal that KCNQ1OT1 regulates MC3T3-E1 cell functions by regulating the miR-421-3p/mTOR axis.

M2 macrophage-derived exosomal miR-486-5p influences the differentiation potential of bone marrow mesenchymal stem cells and osteoporosis.

BACKGROUND: An imbalance between osteogenesis and adipogenesis in bone marrow mesenchymal stem cells (BMMSCs) can cause osteoporosis. Macrophage-derived exosomes (MD-Exos) and microRNAs (miRNAs) enriched in exosomes participate in the differentiation of BMMSCs. METHODS: Bioinformatics methods were used to analyze differentially expressed miRNAs. We cocultured M2 macrophages and BMMSCs to examine the biological function of exosomal microRNA-486-5p (miR-486-5p) on BMMSCs differentiation. Gain-of-function experiments related to osteogenesis were designed to investigate the effects of exosomes carrying miR-486-5p on an ovariectomized (OVX) mice model and the direct impact of miR-486-5p on BMMSCs. A dual luciferase experiment was performed to demonstrate the target gene of miR-486-5p. RESULTS: Bioinformatics analysis identified high expression of miRNA-486 in M2 macrophage-derived exosomes (M2D-Exos). The in vitro results demonstrated that M2 macrophage-derived exosomal miR-486-5p enhanced osteogenic capacity but inhibited the adipogenesis of BMMSCs. The direct effect of miR-486-5p on BMMSCs showed the same effects. Animal experiments revealed that exosomal miR-486-5p rescued bone loss of OVX mice. SMAD2 was characterized as a target gene of miR-486-5p. Pathway analysis showed that M2 macrophage-derived exosomal miR-486-5p stimulated osteogenic differentiation via the TGF-ß/SMAD2 signalling pathway. CONCLUSIONS: Taken together, M2 macrophage-derived exosomal miR-486-5p influences the differentiation potential of BMMSCs through the miR-486-5p/SMAD2/TGF-ß signalling pathway and osteoporosis.

WTAP-Mediated m6A RNA Methylation Regulates the Differentiation of Bone Marrow Mesenchymal Stem Cells via the miR-29b-3p/HDAC4 Axis.

N6-methyladenosine (m6A) methylation, a well-known modification with new epigenetic functions, has been reported to participate in the progression of osteoporosis (OP), providing novel insights into the pathogenesis of OP. However, as the key component of m6A methylation, Wilms tumor 1-associated protein (WTAP) has not been studied in OP. Here we explored the biological role and underlying mechanism of WTAP in OP and the differentiation of bone marrow mesenchymal stem cells (BMMSCs). We demonstrated that WTAP was expressed at low levels in bone specimens from patients with OP and OVX mice. Functionally, WTAP promoted osteogenic differentiation and inhibited adipogenic differentiation of BMMSCs in vitro and in vivo. In addition, microRNA-29b-3p (miR-29b-3p) was identified as a downstream target of WTAP. M6A modifications regulated by WTAP led to increased miR-29b-3p expression. WTAP interacted with the microprocessor protein DGCR8 and accelerated the maturation of pri-miR-29b-3p in an m6A-dependent manner. Target prediction and dual-luciferase reporter assays identified the direct binding sites of miR-29b-3p with histone deacetylase 4 (HDAC4). WTAP-mediated m6A modification promoted osteogenic differentiation and inhibited adipogenic differentiation of BMMSCs through the miR-29b-3p/HDAC4 axis. Furthermore, WTAP-mediated m6A methylation negatively regulates osteoclast differentiation. Collectively, our study first identified a critical role of WTAP-mediated m6A methylation in BMMSC differentiation and highlighted WTAP as a potential therapeutic target for OP treatment.

WTAP-mediated m6A modification modulates bone marrow mesenchymal stem cells differentiation potential and osteoporosis.

An imbalance in the differentiation potential of bone marrow mesenchymal stem cells (BMSCs) is an important pathogenic mechanism underlying osteoporosis (OP). N6-methyladenosine (m6A) is the most common post-transcriptional modification in eukaryotic cells. The role of the Wilms' tumor 1-associated protein (WTAP), a member of the m6A functional protein family, in regulating BMSCs differentiation remains unknown. We used patient-derived and mouse model-derived samples, qRT-PCR, western blot assays, ALP activity assay, ALP, and Alizarin Red staining to determine the changes in mRNA and protein levels of genes and proteins associated with BMSCs differentiation. Histological analysis and micro-CT were used to evaluate developmental changes in the bone. The results determined that WTAP promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs. We used co-immunoprecipitation (co-IP), RNA immunoprecipitation (RIP), methylated RNA immunoprecipitation (MeRIP), RNA pulldown, and dual-luciferase assay to explore the direct mechanism. Mechanistically, the expression of WTAP increased during osteogenic differentiation and significantly promoted pri-miR-181a and pri-miR-181c methylation, which was recognized by YTHDC1, and increased the maturation to miR-181a and miR-181c. MiR-181a and miR-181c inhibited the mRNA expression of SFRP1, promoting the osteogenic differentiation of BMSCs. Our results demonstrated that the WTAP/YTHDC1/miR-181a and miR-181c/SFRP1 axis regulated the differentiation fate of BMSCs, suggesting that it might be a potential therapeutic target for osteoporosis.

Arginine methylation of PPP1CA by CARM1 regulates glucose metabolism and affects osteogenic differentiation and osteoclastic differentiation.

BACKGROUND: The imbalance between osteoblasts and osteoclasts may lead to osteoporosis. Osteoblasts and osteoclasts have different energy requirements, with aerobic glycolysis being the prominent metabolic feature of osteoblasts, while osteoclast differentiation and fusion are driven by oxidative phosphorylation. METHODS: By polymerase chain reaction as well as Western blotting, we assayed coactivator-associated arginine methyltransferase 1 (CARM1) expression in bone tissue, the mouse precranial osteoblast cell line MC3T3-E1 and the mouse monocyte macrophage leukaemia cell line RAW264.7, and expression of related genes during osteogenic differentiation and osteoclast differentiation. Using gene overexpression (lentivirus) and loss-of-function approach (CRISPR/Cas9-mediated knockout) in vitro, we examined whether CARM1 regulates osteogenic differentiation and osteoblast differentiation by metabolic regulation. Transcriptomic assays and metabolomic assays were used to find the mechanism of action of CARM1. Furthermore, in vitro methylation assays were applied to clarify the arginine methylation site of PPP1CA by CARM1. RESULTS: We discovered that CARM1 reprogrammed glucose metabolism in osteoblasts and osteoclasts from oxidative phosphorylation to aerobic glycolysis, thereby promoting osteogenic differentiation and inhibiting osteoclastic differentiation. In vivo experiments revealed that CARM1 significantly decreased bone loss in osteoporosis model mice. Mechanistically, CARM1 methylated R23 of PPP1CA, affected the dephosphorylation of AKT-T450 and AMPK-T172, and increased the activities of phosphofructokinase-1 and pructose-2,6-biphosphatase3, causing an up-regulation of glycolytic flux. At the same time, as a transcriptional coactivator, CARM1 regulated the expression of pyruvate dehydrogenase kinase 3, which resulted in the inhibition of pyruvate dehydrogenase activity and inhibition of the tricarboxylic acid cycle, leading to a subsequent decrease in the flux of oxidative phosphorylation. CONCLUSIONS: These findings reveal for the first time the mechanism by which CARM1 affects both osteogenesis and osteoclast differentiation through metabolic regulation, which may represent a new feasible treatment strategy for osteoporosis.

Susceptibility to ankylosing spondylitis: evidence for the role of ERAP1, TGFb1 and TLR9 gene polymorphisms.

Genetic factors are thought to be crucial in the pathogenesis of ankylosing spondylitis (AS). Recent studies have reported that ERAP1, TGBß1 and TLRs genes are likely to have association with AS in different populations. We carried out this study to determine whether single-nucleotide polymorphisms covering the three genes are associated with AS in a Chinese Han population. Genomic DNA was isolated from the peripheral blood of 328 patients with AS and 627 healthy blood donors from Jinan region as a case-control study. The diagnosis of AS was made according to the modified New York criteria. The ERAP1 rs27044, TGBß1 rs1800470 and TLR9 rs55704465 were genotyped by a polymerase chain reaction--restriction fragment length polymorphism method. Strong association with AS was observed for marker rs27044, but no significant differences were observed between AS patients and controls in the frequencies of the carriership of the alleles rs55704465 and rs1800470. Our data thus indicate that ERAP1 likely constitutes one of AS-associated loci of susceptibility after HLA in Chinese Han population. On the contrary, TGFB1 and TLR9 variations show no association with the susceptibility of AS.

Implanted electro-acupuncture electric stimulation improves outcome of stem cells' transplantation in spinal cord injury.

Spinal cord injury (SCI) is one of the most serious disorders in clinics, and the high disability rate and functional deficits are common issues in patients. Transplantation of bone-marrow-derived mesenchymal stromal cells (BMSCs) into the injured spinal cord is emerging as a novel method in the therapeutics of SCI; however, its application is limited by the poor survival rate of the transplanted cells and low differentiation rate into neurons. Our laboratory recently reported that electrical stimulation (ES) dramatically improves the survival rate of transplanted BMSCs and increases spinal cord functions in animals with spinal cord injury. In this paper, we asked whether implanted electro-acupuncture (iEA) can advance the beneficial effects from the ES treatment in animals with spinal cord injury. We showed that BMSCs transplantation alone resulted in significant functional recovery in animals. Interestingly, iEA with BMSCs treatment induced a significantly higher functional improvement in locomotor functions and SSEP compared to the BMSCs treatment alone. Additionally, we used molecular biology techniques and showed that BMSCs transplantation with iEA treatment significantly increased the number of surviving BMSCs compared to the BMSCs alone group. In conclusion, our experiment showed that the approach of coupling iEA electric stimulation and BMSCs transplantation remarkably promotes functional improvements in animals with spinal cord injury and holds promising potential to treat spinal cord injury in humans.

Socio-economic impacts on flooding: a 4000-year history of the Yellow River, China.

We analyze 4000-year flood history of the lower Yellow River and the history of agricultural development in the middle river by investigating historical writings and quantitative time series data of environmental changes in the river basin. Flood dynamics are characterized by positive feedback loops, critical thresholds of natural processes, and abrupt transitions caused by socio-economic factors. Technological and organizational innovations were dominant driving forces of the flood history. The popularization of iron plows and embarkment of the lower river in the 4th century BC initiated a positive feedback loop on levee breaches. The strength of the feedback loop was enhanced by farming of coarse-sediment producing areas, steep hillslope cultivation, and a new river management paradigm, and finally pushed the flood frequency to its climax in the seventeenth century. The co-evolution of river dynamics and Chinese society is remarkable, especially farming and soil erosion in the middle river, and central authority and river management in the lower river.