Denosumab ameliorates osteoarthritis by protecting cartilage against degradation and modulating subchondral bone remodeling.

Osteoarthritis (OA) is the most prevalent degenerative joint disease worldwide. Effective management for early-stage OA is crucial. Denosumab (DS) has been widely used to treat osteoporosis (OP) and rheumatoid arthritis, but its potential for managing OA remains clear. We assessed the effects of DS on osteoclast activity and chondrocyte apoptosis using tartrate-resistant acid phosphatase (TRAP) assay, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry, and TUNEL staining. To assess the impact of DS on the NF-κB pathway, we performed Western blot and immunofluorescence staining. Additionally, we used an OA model to explore the influence of DS on subchondral bone remodeling and cartilage degeneration in vivo. We found that DS hindered receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis by inhibiting the activity of the NF-κB pathway. Besides, DS alleviated reactive oxygen species (ROS)-induced apoptosis in chondrocytes by regulating the expression of genes related to apoptosis. Moreover, we observed an attenuation of OA-related subchondral bone remodeling and cartilage degeneration in vivo. Our findings indicate that DS could effectively suppress osteoclast activity and chondrocyte apoptosis, thereby mitigating OA-related subchondral bone remodeling and cartilage degeneration. These results provide a mechanistic basis for using DS to treat OA.

Fabrication of ß-Ga2O3 Nanotubes via Sacrificial GaSb-Nanowire Templates.

ß-Ga2O3 nanostructures are attractive wide-band-gap semiconductor materials as they exhibit promising photoelectric properties and potential applications. Despite the extensive efforts on ß-Ga2O3 nanowires, investigations into ß-Ga2O3 nanotubes are rare since the tubular structures are hard to synthesize. In this paper, we report a facile method for fabricating ß-Ga2O3 nanotubes using pre-synthesized GaSb nanowires as sacrificial templates. Through a two-step heating-treatment strategy, the GaSb nanowires are partially oxidized to form ß-Ga2O3 shells, and then, the residual inner parts are removed subsequently in vacuum conditions, yielding delicate hollow ß-Ga2O3 nanotubes. The length, diameter, and thickness of the nanotubes can be customized by using different GaSb nanowires and heating parameters. In situ transmission electron microscopic heating experiments are performed to reveal the transformation dynamics of the ß-Ga2O3 nanotubes, while the Kirkendall effect and the sublimation process are found to be critical. Moreover, photoelectric tests are carried out on the obtained ß-Ga2O3 nanotubes. A photoresponsivity of ~25.9 A/W and a detectivity of ~5.6 × 1011 Jones have been achieved with a single-ß-Ga2O3-nanotube device under an excitation wavelength of 254 nm.

Hydrothermal Synthesis of Te Nanosheets: Growth Mechanism and Electrical Property.

Hydrothermal synthesis is a highly efficient way to yield multiform Te nanosheets. However, the growth mechanisms and property discrepancies between different types of Te nanosheets are still unclear. In this paper, we perform an investigation on this issue by monitoring the hydrothermally synthesized Te nanosheets at different growth stages with transmission electron microscopy and electrical tests. Three main types of Te nanosheets and their variants are revealed including trapezoidal and "V"-shaped configurations. It is found that the different types of Te nanosheets dominate at different reaction stages, indicating a sequential growth scenario. Surfactants and surface energy co-determine the growth kinetics, while the crystallographic attachments lead to specifically included angles of 74° and 41° in the "V"-shaped Te nanosheets. The fractions of the three main types of Te nanosheets as a function of reaction time are statistically tracked, and their crystalline structures, interfaces, and preferential growth orientations are uncovered. Moreover, the electrical properties of the Te nanosheets are tested, and the results show an interface-related feature. These findings provide some new insights into the synthesis and property of low-dimensional Te functional materials.

Revealing the alloying and dealloying behaviours in AuAg nanorods by thermal stimulus.

Binary metallic nanocrystals are attractive as they offer an extra degree of freedom for structure and phase modulation to generate synergistic effects and extraordinary properties. However, whether the binary structures and phases at the nanoscale still follow the rules established on the bulk counterparts remains unclear. In this work, AuAg nanorods were used as a sample to probe into this issue. An in situ heating method by combining aberration-corrected transmission electron microscopes with a chip-based heating holder was employed to perform the heating experiments. It was found that the AuAg nanorods, which initially possessed heterostructures, can be designed and engineered to be gradient phase alloys with thermal pulses over 350 °C. Atomic diffusion inside the rod structures did not alter the shape of the rods but provided a route to fine-tune their properties. At higher temperatures, the discrepant sublimation behaviours between Au and Ag lead to dealloying of the nanorods. Durative sublimation of the Ag element can continuously tailor the lengths of the nanorods while concentrating the Au composition simultaneously. Especially, nearly pure Au nanocrystals can be obtained with the depletion of Ag by sublimation. These findings give insights into the nanoscale structure and phase behaviours in binary alloys and provide an alternative way to fine-tune their structure, phase, and properties.

Strontium ion attenuates osteoarthritis through inhibiting senescence and enhancing autophagy in fibroblast-like synoviocytes.

Osteoarthritis (OA) mainly occurs in the elderly population and seriously affects their quality of life (QOL). Strontium (Sr) ions have shown positive effects on bone tissue and are promising for OA treatment. However, the adequate treatment dosage and underlying mechanisms are unclear. This study investigated the effects and underlying mechanisms of different concentrations of Sr ions in a mouse model of OA induced by destabilization of the medial meniscus (DMM) surgery. DMM-induced OA mice received intra-articular injections of different concentrations of Sr ions, and a suitable concentration of Sr ions was found to improve OA. Furthermore, we investigated the mechanism by which Sr ions mediate senescence and autophagy in fibroblast-like synoviocytes (FLSs) in the synovial tissues of DMM-induced OA mice. OA mice treated with 10 µl of 5 mmol/L SrCl2 showed the greatest improvement in pain-related behavior and cartilage damage. In addition, in vivo and in vitro experiments revealed that Sr ions inhibit senescence and improve the autophagic function of FLSs. We also found that enhancement of the autophagic function of FLSs could effectively slow down senescence. Therefore, we show that Sr ions through the AMPK/mTOR/LC3B-II signal axis improve FLSs autophagy function and delay FLSs senescence, and furthermore, improve OA. These results suggest that senescence and autophagy function of FLSs may serve as promising targets for OA treatment, and that Sr ions may inhibit OA progression through these two targets.

Comparing Clinical and Radiographic Outcomes Between the Self-locking Stand-alone Cage and Conventional Cage-plate Construct: A Five-year Retrospective Cohort Study.

STUDY DESIGN/SETTING: A retrospective cohort study. OBJECTIVE: To evaluate the clinical efficacy of the self-locking stand-alone (SA) cage and conventional cage-plate construct (CPC) in treating degenerative cervical spondylosis with a five-year follow-up. SUMMARY OF BACKGROUND DATA: The SA approach was designed to reduce complications associated with traditional anterior cervical discectomy and fusion. These techniques have been shown to have satisfactory short-term clinical outcomes. Literature describing the mid-term clinical outcomes of SA cage is limited. MATERIALS AND METHODS: We retrospectively analyzed patients with cervical spondylosis who had received an SA device or CPC between 2014 and 2016 at the Xijing Hospital. Participants were matched for sex, age, and operative level. Differences in clinical and radiographic outcomes and the occurrence of postoperative complications between the two groups were analyzed. RESULTS: In total, 207 patients were included (101 with SA and 106 with CPC), the median follow-up for both groups were 60.2 and 60.9 months. Both groups exhibited significant improvements in all measured values compared with the preoperative values. The SA group had a shorter operation time, less intraoperative blood loss, and a significantly lower incidence of dysphagia after surgery than the CPC group ( P <0.05). At the last visit, cage subsidence was 6.9% and 3.8% in the SA and CPC groups, respectively ( P =0.365). The radiographic adjacent segment degeneration (ASD) was significantly lower in the SA group than in the CPC group (6.9% vs. 27.4%, P <0.01). No symptomatic ASD was observed in the SA group, and six (5.7%) cases occurred in the CPC group ( P =0.029). CONCLUSIONS: In this study, the SA cage showed similar efficacy to that of the conventional CPC in treating cervical spondylosis using anterior cervical discectomy and fusion, with a significant reduction in the incidence of immediate postoperative dysphagia and mid-term ASD.

Revealing the Phase Segregation and Evolution Dynamics in Binary Nanoalloys via Electron Beam-Assisted Ultrafast Heating and Cooling.

Gas-phase synthesized binary nanoparticles (NPs) possess ultraclean surfaces, which benefit versatile uses in sensors and catalysts. However, precise control of their configuration and properties is still a big challenge because the growth mechanism and phase evolution dynamics in these NPs are very hard to unveil. Here, we report a strategy to investigate the phase evolution dynamics in binary NPs by using e-beam assisted ultrafast local heating and cooling inside a transmission electron microscope. With this strategy, the phase segregation and corresponding shape evolution of PbBi NPs are in situ revealed. It is found that the as-prepared PbBi alloy NPs will transform into heterostructures under e-beam stimulated structural relaxation, leading to the formation of featured Janus configurations with faceted Bi polyhedron parts and intermetallic hemisphere parts. During phase segregation, Pb1Bi1 and Pb7Bi3 phases are captured and identified, and a model of phase and shape evolution of PbBi nanoalloys is developed and contrasted with that of their bulk counterparts. These findings benefit the understanding of the phase dynamics of binary NPs and can provide in-depth information for engineering their structures for practical applications.

Precise Arthroscopic Mini-trochleoplasty and Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability With Severe Trochlear Dysplasia.

More than 100 surgical procedures have been reported to address recurrent patellar instability. Trochlear dysplasia is the most common finding among the anatomic risk factors for recurrent patellar instability. Various studies have shown that trochleoplasty combined with medial patellofemoral ligament reconstruction is an effective technique to treat recurrent patellar instability. Nevertheless, trochleoplasty is still a daunting procedure for surgeons because of its multiple and gloomy complications. This article introduces a technique to treat recurrent patellar instability with severe trochlear dysplasia: precise arthroscopic mini-trochleoplasty (PAM trochleoplasty) combined with medial patellofemoral ligament reconstruction. This technique precisely removes the supratrochlear spur and trochlear bump, accurately reshapes the trochlear sulcus with minimal invasion and less osteotomy volume, and keeps the sulcus cartilage intact. The purpose of this technique is to develop trochleoplasty into a common and safe technique, which has good outcomes and low complications.

Permanently Avoiding Steam on Camera for Arthroscopy by a Simple Device.

Steam on the camera may happen in any arthroscopic procedure, especially in shoulder arthroscopy. Although multiple techniques and devices have been applied to avoid steam, it still cannot be prevented completely. We designed a simple device to terminate this problem by protecting against the ingress of water.

A novel bacterial cellulose membrane immobilized with human umbilical cord mesenchymal stem cells-derived exosome prevents epidural fibrosis.

INTRODUCTION: Failed back surgery syndrome is a situation where there is failure after lumbar surgery aimed at correcting lumbar disease that is characterized by continuous back and/or leg pain. Epidural fibrosis and adhesions are among the major causes of failed back surgery syndrome. In recent years, several biomaterials have been applied as barriers or deterrents to prevent the compression of neural structures by postsurgical fibrosis. METHODS: In this study, a new bacterial cellulose (BC) anti-adhesion membrane, composed of exosomes from human umbilical cord mesenchymal stem cells, was developed. Its structure and morphology, water content, thickness, and mechanical properties of elasticity were analyzed and characterized. The degradation of the BC+exosomes (BC+Exos) membrane in vitro was evaluated, and its in vitro cytotoxicity and in vivo biocompatibility were tested. The prevention effect of BC+Exos membrane on epidural fibrosis post-laminectomy in a rabbit model was investigated. RESULTS: The BC+Exos membrane showed a three-dimensional network structure constituted of high-purity cellulose and moderate mechanical properties. No degeneration was observed. The BC+Exos membrane showed no cytotoxicity and displayed biocompatibility in vivo. The BC+Exos film was able to inhibit epidural fibrosis and peridural adhesions. CONCLUSION: Based on the current findings, the BC+Exos membrane is a promising material to prevent postoperative epidural fibrosis and adhesion.

Discover cervical disc arthroplasty versus anterior cervical discectomy and fusion in symptomatic cervical disc diseases: A meta-analysis.

OBJECTIVE: Symptomatic cervical disc disease (SCDD) is a common degenerative disease, and Discover artificial cervical disc, a new-generation nonconstrained artificial disk, has been developed and performed gradually to treat it. We performed this meta-analysis to compare the efficacy and safety between Discover cervical disc arthroplasty (DCDA) and anterior cervical discectomy and fusion (ACDF) for SCDD. METHODS: An exhaustive literature search of PubMed, EMBASE, and the Cochrane Library was conducted to identify randomized controlled trials that compared DCDA with ACDF for patients suffering SCDD. A random-effect model was used. Results were reported as standardized mean difference or risk ratio with 95% confidence interval. RESULTS: Of 33 articles identified, six studies were included. Compared with ACDF, DCDA demonstrated shorter operation time (P < 0.0001), and better range of motion (ROM) at the operative level (P < 0.00001). But no significant differences were observed in blood loss, neck disability index (NDI) scores, neck and arm pain scores, Japanese orthopaedic association (JOA) scores, secondary surgery procedures and adverse events (P > 0.05). Subgroup analyses did not demonstrated significant differences. CONCLUSION: In conclusion, DCDA presented shorter operation time, and better ROM at the operative level. However, no significant differences were observed in blood loss, NDI scores, neck and arm pain scores, JOA scores, secondary surgery procedures and adverse events between the two groups. Additionally, more studies of high quality with mid- to long-term follow-up are required in future.

Fibulin-4 reduces extracellular matrix production and suppresses chondrocyte differentiation via DKK1- mediated canonical Wnt/ß-catenin signaling.

Fibulin-4 is an extracellular matrix (ECM) protein implicated in connective tissue development and elastic fiber formation. However, little is known about the underlying function of Fibulin-4 in cartilage development. The aim of this study was to investigate the role and probable mechanism of Fibulin-4 stimulation in ECM production and chondrocyte differentiation. Fibulin-4 has been observed to be abnormally elevated and matrix metalloproteinases 13 (MMP13) level was highly expressed in human osteoarthritis (OA) chondrocytes. In the chondrogenic cell line ATDC5, Fibulin-4 stimulation profoundly inhibited the expression of ECM gene type II collagen (Col2a1), aggrecan (Acan), and type X collagen (Col10a1). Overexpression of Fibulin-4 attenuated the expression of master transcription factors Sox6, Sox9 and Runx2, but had no effect on the expression of Sox5. Additionally, Fibulin-4 stimulation activated canonical Wnt pathway by reducing the expression of Wnt inhibitor DKK1 but not Sost. Moreover, Fibulin-4 augmented the expression of Wnt/ß-catenin signaling target genes like ß-catenin and Wnt-3a as well as diminished GSK-3ß activation, and DKK1 abolished the effect of Fibulin-4 on chondrocyte differentiation, suggesting that Fibulin-4 is an important regulator of ECM production and chondrocyte differentiation through DKK1-mediated Wnt/ß-catenin signaling. Our study provides evidence of a previously unknown link between Fibulin-4 and the canonical Wnt/ß-catenin pathway that may contribute to our understanding of the molecular mechanisms of OA.

A genome wide analysis of alternative splicing events during the osteogenic differentiation of human cartilage endplate-derived stem cells.

Low back pain is a prevalent disease, which leads to suffering and disabilities in a vast number of individuals. Degenerative disc diseases are usually the underlying causes of low back pain. However, the pathogenesis of degenerative disc diseases is highly complex and difficult to determine. Current therapies for degenerative disc diseases are various. In particular, cell-based therapies have proven to be effective and promising. Our research group has previously isolated and identified the cartilage endplate­derived stem cells. In addition, alternative splicing is a sophisticated regulatory mechanism, which greatly increases cellular complexity and phenotypic diversity of eukaryotic organisms. The present study continued to investigate alternative splicing events in osteogenic differentiation of cartilage endplate­derived stem cells. An Affymetrix Human Transcriptome Array 2.0 was used to detect splicing changes between the control and differentiated samples. Additionally, molecular function and pathway analysis were also performed. Following rigorous bioinformatics analysis of the data, 3,802 alternatively spliced genes were identified, and 10 of these were selected for validation by reverse transcription­polymerase chain reaction. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analysis also revealed numerous enriched GO terms and signaling pathways. To the best of our knowledge, the present study is the first to investigate alternative splicing mechanisms in osteogenic differentiation of stem cells on a genome­wide scale. The illumination of molecular mechanisms of stem cell osteogenic differentiation may assist the development novel bioengineered methods to treat degenerative disc diseases.

Rivaroxaban for thromboprophylaxis after total hip or knee arthroplasty: a meta-analysis with trial sequential analysis of randomized controlled trials.

Venous thromboembolism (VTE) is the most widespread severe complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA). We conducted this meta-analysis to further validate the benefits and harms of rivaroxaban use for thromboprophylaxis after THA or TKA. We thoroughly searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Trial sequential analysis (TSA) was applied to test the robustness of our findings and to obtain a more conservative estimation. Of 316 articles screened, nine studies were included. Compared with enoxaparin, rivaroxaban significantly reduced symptomatic VTE (P = 0.0001) and symptomatic deep vein thrombosis (DVT; P = 0.0001) but not symptomatic pulmonary embolism (P = 0.57). Furthermore, rivaroxaban was not associated with an increase in all-cause mortality, clinically relevant non-major bleeding and postoperative wound infection. However, the findings were accompanied by an increase in major bleeding (P = 0.02). The TSA demonstrated that the cumulative z-curve crossed the traditional boundary but not the trial sequential monitoring boundary and did not reach the required information size for major bleeding. Rivaroxaban was more beneficial than enoxaparin for preventing symptomatic DVT but increased the risk of major bleeding. According to the TSA results, more evidence is needed to verify the risk of major bleeding with rivaroxaban.

Anterior Facetectomy for Reduction of Cervical Facet Dislocation.

STUDY DESIGN: Technique report and case series. OBJECTIVE: The aim of this study was to develop a new surgical technique for anterior reduction in management of unilateral/bilateral facet dislocations and to report the results of 8 patients with successful outcomes associated with this approach. SUMMARY OF BACKGROUND DATA: The anterior-only surgical procedure, including discectomy, open reduction, fusion, and fixation, is a recommended approach in the treatment of cervical facet dislocations. This approach is with a failure rate of up to 40%. When it fails, a posterior approach is usually required. We have developed a new surgical approach with facetectomy for anterior reduction of cervical facet dislocations. This technique is especially useful for delayed management of unilateral/bilateral facet dislocation patients who failed the conventional anterior open reduction to avoid a posterior procedure. METHODS: Eight patients with cervical facet dislocations who failed in the conventional anterior reduction were surgically treated by the anterior facetectomy reduction technique. After discectomy, anteromedial foraminotomy was performed by resection of posterior foraminal part or total of uncovertebral joint. After the nerve root was retracted cephalad in the neuroforamina, the edge of the dislocated superior facet was broken to achieve reduction. RESULTS: Postoperatively, all patients have obtained successful reduction and satisfactory anatomic sagittal alignment. There were no complications attributable to the use of this technique. CONCLUSION: Anterior facetectomy reduction represents a safe and efficacious but technically challenging option for the treatment of cervical facet dislocation. LEVEL OF EVIDENCE: 5.

miR-29c-3p promotes senescence of human mesenchymal stem cells by targeting CNOT6 through p53-p21 and p16-pRB pathways.

Mesenchymal stem cells (MSCs) are important seed cells for tissue engineering and are promising targets for cell-based therapies. However, the replicative senescence of MSCs during in vitro culture limits their research and clinical applications. The molecular mechanisms underlying the replicative senescence of MSCs are not fully understood. Evidence suggests that miRNAs play important roles in replicative senescence. A microarray analysis found that the miR-29c-3p level was significantly increased during the MSC senescence process. In our study, we investigated the roles of miR-29c-3p in senescence of MSCs. We cultured MSCs for long periods of time, up and down-regulated the miR-29c-3p expression in MSCs, and examined the senescent phenotype changes. The over-expression of miR-29c-3p led to enhanced senescence-associated-ß-galactosidase (SA-ß-gal) staining, senescence associated secretory phenotype (SASP), senescence associated heterochromatic foci (SAHF), reduced proliferation ability, retarded osteogenic differentiation and corresponding changes in senescence markers, whereas the miR-29c-3p down-regulation had the opposite results. Dual-luciferase reporter assays demonstrated that CNOT6 is the target gene of miR-29c-3p. Knockdown of CNOT6 confirmed its inhibitory effects on the senescence of MSCs. In addition, Western blot results showed that both the p53-p21 and the p16-pRB pathways were activated during the miR-29c-3p-induced senescence of MSCs. In conclusion, our results demonstrate that miR-29c-3p promotes the senescence of MSCs by targeting CNOT6 through p53-p21 and p16-pRB pathways and highlight the contribution of post-transcriptional regulation to stem cell senescence.

Epidemiological features of traumatic spinal cord injury in Chongqing, China.

OBJECTIVE: To describe the epidemiological characteristics and trends of traumatic spinal cord injury in Chongqing, China. STUDY DESIGN: Hospital-based retrospective research. SETTING: Xinqiao Hospital, Chongqing. METHODS: We reviewed medical records of 554 patients with traumatic spinal cord injury (TSCI) admitted to Xinqiao Hospital from 2009 to 2013. Variables included gender, age, marital status, etiology, occupation, time of injury, level of injury, and severity of injury, the length of hospital stay, and treatment. RESULTS: The mean age of patients with TSCI was 45.6 ± 13.8 years, and the male/female ratio was 4.33:1. 94.2% (522 patients) of all patients with TSCI were married. Falls, comprising low falls and high falls (10.8% and 50.9%, respectively), were the leading reason for a hospital visit. And the second reason was MVCs (21.8%). The most common injury site was the cervical spinal cord, accounting for nearly more than 54%. The length of hospital stay ranged between 1 and 219 days (mean: 28.3 days). The proportions of complete tetraplegia, incomplete tetraplegia, complete paraplegia and incomplete paraplegia were 17.1%, 37.8%, 22.2%, and 22.9%, respectively. CONCLUSION: The result revealed that the proportion of males was higher, as well as falls and MVCs were the first two main reasons, with older mean age of patients with TSCI than other countries. The occupations with highest risk for TSCI were peasants and laborers. All of these results prompted that preventive methods should be based on the characteristics of different type of patients with TSCI.

Posterior 2-Level Vertebral Column Resection for the Treatment of Progressive Rotational Dislocation in Kyphoscoliotic Deformities.

OBJECTIVE: Progressive rotational dislocation of the spine is rare and surgical treatment is challenging. Few reports have described surgical decompression, fusion, and partial correction by traditional 2-stage anterior decompression and the posterior fixation technique. The goal of this retrospective study was to report a series of 6 patients with this deformity and the outcome after treatment by posterior-only 2-level vertebral column resection (PVCR). METHODS: Between 2011 and 2014, 6 patients were treated for kyphoscoliotic deformities with progressive rotational dislocation. In these 6 patients (2 males and 4 females), the diagnosis included 4 cases of congenital kyphosis and 2 cases of neurofibromatosis; the distribution of spine level was from T4 to T11; the kyphosis angle of the patients was 115° (range, 107-125°); the scoliosis angle was 97° (range, 80°-117°); follow-up ranged from 13 to 51 months (mean, 27 months). Four patients developed progressive onset of neurologic deficit. All patients underwent surgery by 2-level PVCR for decompression and correction of kyphoscoliosis. RESULTS: Postoperatively, the patients all had different kyphosis correction rates, from 49% to 72% (mean, 63%) and scoliosis correction rates, from 57% to 78% (mean, 65%). All patients achieved successful spinal fusion with less than 3° of loss of correction at the latest follow-up evaluation. The 4 patients with incomplete neurologic deficits improved 1 or 2 American Spinal Injury Association scales at follow-up of at least 6 months. CONCLUSIONS: Two-level PVCR is a safe and efficacious surgical option for the treatment of rotational dislocation in kyphoscoliosis and associated neurologic deficit.

Global Gene Expression Profiling and Alternative Splicing Events during the Chondrogenic Differentiation of Human Cartilage Endplate-Derived Stem Cells.

Low back pain (LBP) is a very prevalent disease and degenerative disc diseases (DDDs) usually account for the LBP. However, the pathogenesis of DDDs is complicated and difficult to elucidate. Alternative splicing is a sophisticated regulatory process which greatly increases cellular complexity and phenotypic diversity of eukaryotic organisms. In addition, the cartilage endplate-derived stem cells have been discovered and identified by our research group. In this paper, we continue to investigate gene expression profiling and alternative splicing events during chondrogenic differentiation of cartilage endplate-derived stem cells. We adopted Affymetrix Human Transcriptome Array 2.0 (HTA 2.0) to compare the transcriptional and splicing changes between the control and differentiated samples. RT-PCR and quantitative PCR are used to validate the microarray results. The GO and KEGG pathway analysis was also performed. After bioinformatics analysis of the data, we detected 1953 differentially expressed genes. In terms of alternative splicing, the Splicing Index algorithm was used to select alternatively spliced genes. We detected 4411 alternatively spliced genes. GO and KEGG pathway analysis also revealed several functionally involved biological processes and signaling pathways. To our knowledge, this is the first study to investigate the alternative splicing mechanisms in chondrogenic differentiation of stem cells on a genome-wide scale.

[Transforming growth factor-ß1 induces bone marrow-derived mesenchymal stem cells to differentiate into cancer-associated fibroblasts].

OBJECTIVE: To investigate the effect of transforming growth factor-ß1 (TGF-ß1) on the differentiation of bone marrow-derived mesenchymal stem cells (MSCs) into cancer-associated fibroblasts(CAFs). METHODS: MSCs were cultured in α-MEM with recombinant human TGF-ß1 or in tumor-conditioned medium.The expression of CAFs markers were detected by immunofluorescence and quantitative RT-PCR. RESULTS: The qRT-PCR assay showed that the expression of CAFs markers FAP, ACTA, CAV, CCL5, CXCR4, FSP1, SDF-1 and vimentin were 9.92±2.16, 7.76±1.28, 3.04±0.95, 3.28±2.16, 2.13±0.71, 1.41±0.66, 2.25±0.86 and 1.38±0.56, respectively, significantly upregulated in the MSCs co-cultured with TGF-ß1 or TCM. The relative levels of FAP, ACTA, CAV, CCL5, CXCR4, FSP1, SDF-1 and vimentin mRNA in the TCM group were 7.52±1.76, 5.02±1.18, 1.98±1.19, 1.82±1.19, 2.95±0.86, 1.44±0.67, 2.08±0.74 and 1.47±0.55, respectively, indicating that MSCs can express CAFs phenotype.TGF beta signaling pathway inhibitor SB-431542 could inhibit the differentiation. Both immunofluorescence and Western blot confirmed the above results. CONCLUSIONS: TGF-ß1 induces differentiation of local MSCs to CAFs by upregulating the expression of pSmad3, so as to further promote the growth of cancer cells.