Therapeutic potential of tyrosine-protein kinase MET in osteosarcoma.

Osteosarcoma, the most prevalent primary bone tumor in children and young adults, can often be successfully treated with standard chemotherapy and surgery when diagnosed at an early stage. However, patients presenting with metastases face significant challenges in achieving a cure. Despite advancements in classical therapies over the past few decades, clinical outcomes for osteosarcoma have not substantially improved. Recently, there has been increased understanding of the biology of osteosarcoma, leading to the identification of new therapeutic targets. One such target is MET, a tyrosine kinase receptor for Hepatocyte Growth Factor (HGF) encoded by the MET gene. In vitro and in vivo studies have demonstrated that the HGF/MET pathway plays a crucial role in cancer growth, invasion, metastasis, and drug resistance across various cancers. Clinical trials targeting this pathway are already underway for lung cancer and hepatocellular carcinoma. Moreover, MET has also been implicated in promoting osteosarcoma progression. This review summarizes 3 decades' worth of research on MET's involvement in osteosarcoma and further explores its potential as a therapeutic target for patients with this disease.

A modified method for reconstruction of posterior tibial tendon after resection of juvenile painful type II accessory navicular.

BACKGROUND: The surgical treatment of accessory navicular (AN) is divided into simple resection of AN and Kidner surgery used to reconstruct posterior tibial tendon (PTT) after AN resection. However, both of these procedures have certain disadvantages. Herein, we proposed a modified method to reconstruct PTT and compared the short-term clinical effect of our method with the modified Kidner procedure. METHODS: We collected data from 23 adolescent children with painful type II AN treated in our department between January 2015 and June 2020. The American Orthopedic Foot and Ankle Society Ankle-Hind foot (AOFAS-AH) Scores, the Meary Angle, and Pitch Angle of the lateral weight-bearing plain radiographs status were recorded before and after the operation to evaluate the treatment outcomes. RESULTS: In the modified Kidner surgery (MK) group, the median AOFAS-AH increased from 61 (59-68) to 87 (83-91) (P < 0.05); the Pitch angle of the lateral weight-bearing plain radiographs increased from 13.0 (8-18) to 17.4 (14-22), and the Meary angle decreased from 18.3 (14-24) to 14.2 (8-20) (P < 0.05). In the PTT preservation folded suture (FS) group, the median AOFAS-AH increased from 61 (59-68) to 87 (85-91) (P < 0.05); the Pitch angle of the lateral weight-bearing plain radiographs increased from 12.3 (7-18) to 18.4 (15-26), and the Meary angle decreased from 17.8 (13-23) to 5.7 (3-8) (P < 0.05). There was no significant difference in AOFAS-AH postoperative scores between the FS group and MK group; however, the improvement on Pitch and Meary angle of the lateral weight-bearing plain radiographs was significantly better in the FS group than in MK group (P < 0.05). CONCLUSIONS: For painful type II AN in juvenile patients, the insertion-preserving folding suture procedure had similar short-term results on AOFAS-AH scores but greater improvement in the Meary angle and the Pitch Angle than the modified Kidner method. LEVEL OF EVIDENCE: III.

Efficacy of modified kidner procedure combined with subtalar arthroereisis treating adolescent type 2 painful accessory navicular with flexible flatfoot.

Purpose: To investigate the clinical efficacy of modified kidner procedure combined with subtalar arthroereisis in the treatment of adolescent type II painful accessory navicular with flexible flatfoot. Methods: From January 2018 to January 2022, 25 adolescent patients (40 feet) with painful type II accessory navicular and flexible flatfoot admitted to our hospital were enrolled in the study, including 13 males (23 feet) and 12 females (17 feet). All patients underwent modified kidner procedure combined with subtalar joint arthrodesis. The Meary's Angle, the first metatarsal Angle of talus (APTMT), the second metatarsal Angle of talus, Pitch Angle, talus tilt Angle, talonavicular coverage Angle (TCA), talus calcaneal Angle (LTCA), and calcaneal Angle were measured on weight-bearing anteroposterior and lateral x-ray films before operation and at last follow-up. The American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score and visual analogue scale (VAS) were used to evaluate the improvement of foot function and pain. Results: All patients were followed up for average 17.4 ± 2.6 months (12-24). The incisions of 25 patients healed by first intention. The weight-bearing anteroposterior and lateral x-ray films of the foot showed that the suture anchors did not pull out or break, and the foot arch did not collapse further. There was no screw withdrawal or secondary operation to remove the screw in all patients. At the last follow-up, the postoperative visual analogue scale (VAS) score of the affected foot was significantly lower than that before operation (P < 0.01), and the American Orthopaedic Foot and Ankle Society (AOFAS) foot function score was significantly higher than that before operation (P < 0.01). At the last follow-up, the weight-bearing anteroposterior and lateral foot x-ray films showed that: The Meary's Angle, the first metatarsal Angle of the talus (APTMT), the second metatarsal Angle of the talus, Pitch Angle, talar tilt Angle, talonavicular overbite Angle (TCA), talocalcaneal Angle (LTCA), and calcaneal Angle significantly improved when compared with those before operation (P < 0.01). Conclusions: The modified kidner procedure combined with subtalar arthroereisis has a good clinical effect in the treatment of adolescent type II painful accessory navicular with flexible flatfoot, which can effectively improve the pain symptoms, improve the foot function and imaging manifestations, and correct the flatfoot deformity.

Effectiveness of platelet-rich plasma in the treatment of Achilles tendon disease.

BACKGROUND: The effectiveness of Platelet-Rich Plasma (PRP) in the treatment of patients with Achilles tendon rupture (ATR) and Achilles tendinopathy (AT) has been controversial. AIM: To assess PRP injections' effectiveness in treating ATR and AT. METHODS: A comprehensive review of relevant literature was conducted utilizing multiple databases such as Cochrane Library, PubMed, Web of Science, Chinese Science and Technology Journal, EMBASE, and China Biomedical CD-ROM. The present investigation integrated randomized controlled trials that assessed the effectiveness of platelet-rich plasma injections in managing individuals with Achilles tendon rupture and tendinopathy. The eligibility criteria for the trials encompassed publications that were published within the timeframe of January 1, 1966 to December 2022. The statistical analysis was performed utilizing the Review Manager 5.4.1, the visual analogue scale (VAS), Victorian Institute Ankle Function Scale (VISA-A), and Achilles Tendon Thickness were used to assess outcomes. RESULTS: This meta-analysis included 13 randomized controlled trials, 8 of which were randomized controlled trials of PRP for AT and 5 of which were randomized controlled trials of PRP for ATR. PRP for AT at 6 wk [weighted mean difference (WMD) = 1.92, 95%CI: -0.54 to 4.38, I2 = 34%], at 3 mo [WMD = 0.20, 95%CI: -2.65 to 3.05, I2 = 60%], and 6 mo [WMD = 2.75, 95%CI: -2.76 to 8.26, I2 = 87%) after which there was no significant difference in VISA-A scores between the PRP and control groups. There was no significant difference in VAS scores between the PRP group and the control group after 6 wk [WMD = 6.75, 95%CI: -6.12 to 19.62, I2 = 69%] and 6 mo [WMD = 10.46, 95%CI: -2.44 to 23.37, I2 = 69%] of treatment, and at mid-treatment at 3 mo [WMD = 11.30, 95%CI: 7.33 to 15.27, I2 = 0%] after mid-treatment, the PRP group demonstrated better outcomes than the control group. Post-treatment patient satisfaction [WMD = 1.07, 95%CI: 0.84 to 1.35, I2 = 0%], Achilles tendon thickness [WMD = 0.34, 95%CI: -0.04 to 0.71, I2 = 61%] and return to sport [WMD = 1.11, 95%CI: 0.87 to 1.42, I2 = 0%] were not significantly different between the PRP and control groups. The study did not find any statistically significant distinction between the groups that received PRP treatment and those that did not, regarding the Victorian Institute of Sport Assessment - Achilles scores at 3 mo [WMD = -1.49, 95%CI: -5.24 to 2.25, I2 = 0%], 6 mo [WMD = -0.24, 95%CI: -3.80 to 3.32, I2 = 0%], and 12 mo [WMD = -2.02, 95%CI: -5.34 to 1.29, I2 = 87%] for ATR patients. Additionally, no significant difference was observed between the PRP and the control groups in improving Heel lift height respectively at 6 mo [WMD = -3.96, 95%CI: -8.61 to 0.69, I2 = 0%] and 12 mo [WMD = -1.66, 95%CI: -11.15 to 7.83, I2 = 0%] for ATR patients. There was no significant difference in calf circumference between the PRP group and the control group after 6 mo [WMD = 1.01, 95%CI: -0.78 to 2.80, I2 = 54%] and 12 mo [WMD = -0.55, 95%CI: -2.2 to 1.09, I2 = 0%] of treatment. There was no significant difference in ankle mobility between the PRP and control groups at 6 mo of treatment [WMD = -0.38, 95%CI: -2.34 to 1.58, I2 = 82%] and after 12 mo of treatment [WMD = -0.98, 95%CI: -1.41 to -0.56, I2 = 10%] there was a significant improvement in ankle mobility between the PRP and control groups. There was no significant difference in the rate of return to exercise after treatment [WMD = 1.20, 95%CI: 0.77 to 1.87, I2 = 0%] and the rate of adverse events [WMD = 0.85, 95%CI: 0.50 to 1.45, I2 = 0%] between the PRP group and the control group. CONCLUSION: The use of PRP for AT improved the patient's immediate VAS scores but not VISA-A scores, changes in Achilles tendon thickness, patient satisfaction, or return to sport. Treatment of ATR with PRP injections alone improved long-term ankle mobility but had no significant effect on VISA-A scores, single heel lift height, calf circumference or return to sport. Additional research employing more extensive sampling sizes, more strict experimental methods, and standard methodologies may be necessary to yield more dependable and precise findings.

Modified ulnar lengthening for correction of the Masada type 2 forearm deformity in hereditary multiple exostosis.

Few articles have reported on the treatment of Masada type 2 forearm deformities in hereditary multiple exostosis, possibly because of the high redislocation rate and other complications. This study precisely declares the use of modified ulnar lengthening by an Ilizarov external fixation with tumour excision for the treatment of Masada type 2 forearm deformities. 20 children with Masada type 2 forearm deformities were admitted for surgical treatment at our hospital from February 2014 to February 2021. There were 13 girls and 7 boys, ranging in age from 3.5 to 15 years (mean: 9 years) at the time of operation. We removed the prominent osteochondromas of the distal ulna and the proximal radius, positioned a classic Ilizarov external fixator on the forearm and then performed ulnar transverse one-third proximal diaphyseal subperiosteal osteotomy. We adopted modified ulnar lengthening postoperatively. The effects of surgical correction of deformity and functional improvement of the limb were assessed via regular follow-up and X-ray. The patients were followed up for 36 months, and the ulna was lengthened 26.99 mm on average; all radial heads remained relocated. The radiographic evaluations, including relative ulnar shortening, radial articular angle, and carpal slip, were improved. The functions of the elbow and forearm were all improved after surgery. Modified ulnar lengthening by an Ilizarov external fixation with tumour excision for the treatment of Masada type 2 forearm deformities in hereditary multiple exostoses has been proven to be an effective and reliable technique in the early stage.

LncRNA KIAA0087 suppresses the progression of osteosarcoma by mediating the SOCS1/JAK2/STAT3 signaling pathway.

Long noncoding RNAs (lncRNAs), widely expressed in mammalian cells, play pivotal roles in osteosarcoma (OS) progression. Nevertheless, the detailed molecular mechanisms of lncRNA KIAA0087 in OS remain obscure. Here, the roles of KIAA0087 in OS tumorigenesis were investigated. KIAA0087 and miR-411-3p levels were detected by RT-qPCR. Malignant properties were assessed by CCK-8, colony formation, flow cytometry, wound healing, and transwell assays. SOCS1, EMT, and JAK2/STAT3 pathway-related protein levels were measured by western blotting. Direct binding between miR-411-3p and KIAA0087/SOCS1 was validated by a dual-luciferase reporter, RIP, and FISH assays. In vivo growth and lung metastasis were evaluated in nude mice. The expression levels of SOCS1, Ki-67, E-cadherin, and N-cadherin in tumor tissues were measured by immunohistochemical staining. Downregulation of KIAA0087 and SOCS1 and upregulation of miR-411-3p were found in OS tissues and cells. Low expression of KIAA0087 was associated with a poor survival rate. Forced expression of KIAA0087 or miR-411-3p inhibition repressed the growth, migration, invasion, EMT, and activation of the JAK2/STAT3 pathway and triggered apoptosis of OS cells. However, the opposite results were found with KIAA0087 knockdown or miR-411-3p overexpression. Mechanistic experiments indicated that KIAA0087 enhanced SOCS1 expression to inactivate the JAK2/STAT3 pathway by sponging miR-411-3p. Rescue experiments revealed that the antitumor effects of KIAA0087 overexpression or miR-411-3p suppression were counteracted by miR-411-3p mimics or SOCS1 inhibition, respectively. Finally, in vivo tumor growth and lung metastasis were inhibited in KIAA0087-overexpressing or miR-411-3p-inhibited OS cells. In summary, the downregulation of KIAA0087 promotes the growth, metastasis, and EMT of OS by targeting the miR-411-3p-mediated SOCS1/JAK2/STAT3 pathway.

Identification of an EMT-related gene-based prognostic signature in osteosarcoma.

BACKGROUND: The correlation between epithelial-mesenchymal transition (EMT) and osteosarcoma (OS) has been widely reported. Integration of the EMT-related genes to predict the prognosis is significant for investigating the mechanism of EMT in OS. Here, we aimed to construct a prognostic EMT-related gene signature for OS. METHODS: Transcriptomic and survival data of OS patients were downloaded from Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO). We performed univariate Cox regression, least absolute shrinkage and selection operator (LASSO) regression, and stepwise multivariate Cox regression analysis to construct EMT-related gene signatures. Kaplan-Meier analysis and time-dependent receiver operating characteristic (ROC) were applied to evaluate its predictive performance. GSVA, ssGSEA, ESTIMATE, and scRNA-seq were performed to investigate the tumor microenvironment, and the correlation between IC50 of drugs and ERG score was investigated. Furthermore, Edu and transwell experiments were conducted to assess the malignancy of OS cells. RESULTS: We constructed a novel EMT-related gene signature (including CDK3, MYC, UHRF2, STC2, COL5A2, MMD, and EHMT2) for outcome prediction of OS. According to the signature, patients stratified into high- and low-ERG-score groups exhibited significantly different prognoses. ROC curves and Kaplan-Meier analysis revealed a promising performance of the signature with external validation. GSVA, ssGSEA, ESTIMATE algorithm, and scRNA-seq excavated EMT-related pathways and suggested the correlation between ERG score and immune activation. Notably, the pivotal gene CDK3 was upregulated in OS tissue and positively related to OS cell proliferation and migration. CONCLUSION: Our EMT-related gene signature might reference OS risk stratification and guide clinical strategies as an independent prognostic factor in OS.

Post-traumatic heterotopic ossification in front of the ankle joint for 23 years: A case report and review of literature.

BACKGROUND: Heterotopic ossification (HO) refers to the formation of new bone in non-skeletal tissues such as muscles, tendons or other soft tissues. Severe muscle and soft tissue injury often lead to the formation of HO. However, anterior HO of the ankle is rarely reported. CASE SUMMARY: We report a patient with massive HO in front of the ankle joint for 23 years. In 1998, the patient was injured by a falling object on the right lower extremity, which gradually formed a massive heterotopic bone change in the right calf and dorsum of the foot. The patient did not develop gradual ankle function limitations until nearly 36 mo ago, and underwent resection of HO. Even after 23 years and resection of HO, the ankle joint was still able to move. CONCLUSION: It is recommended that the orthopedist should be aware of HO and distinguish it from bone tumor.

Max interacting protein 1 induces IL-17-producing T helper/regulatory T imbalance in osteoarthritis by upregulating tectonic family member 2.

BACKGROUND/AIM: Osteoarthritis (OA) is a common total joint disorder associated with regulatory T cell (Treg)/IL-17-producing T helper (Th17) cell imbalance. This study elucidated the mechanism underlying Th17/Treg imbalance during OA progression. METHODS: CD4+ T cells were isolated and induced to differentiate and obtain Th17 and Treg cells, and an OA mouse model was established by anterior cruciate ligament transection surgery, followed by loss- and gain-of-function assays. Max interacting protein 1 (MXI1), tectonic family member 2 (TCTN2), Forkhead Box Protein P3 (Foxp3), signal transducer and activator of transcription 3 (STAT3), and retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt) expression was determined in cells and mice, accompanied by the measurement of the proportion of Th17 and Treg cells and the levels of interleukin (IL)- 1ß, tumor necrosis factor (TNF)-α, and interferon (INF)-γ. Articular cartilage histopathology was observed by hematoxylin and eosin staining and Safranin O-Fast Green staining. Relationship between MXI1 and TCTN2 was assessed. RESULTS: Bioinformatics analysis identified MXI1 and TCTN2 upregulation in OA patients. Mechanistically, MXI1 bound to TCTN2 promoter to promote its transcription. Upregulated MXI1 boosted INF-γ, STAT3, IL-1ß, TNF-α, and RORγt levels and Th17 cell differentiation, but restricted Foxp3 expression and Treg cell differentiation in CD4+ T cells. Effects caused by overexpressed MXI1 were negated by silenced TCTN2. Also, the impacts of MXI1 overexpression on Th17/Treg imbalance and IL-1ß, STAT3, TNF-α, Foxp3, INF-γ, and RORγt expression were further validated in OA mice, accompanied by aggravated articular cartilage degeneration. CONCLUSION: Conclusively, MXI1 facilitated Th17/Treg imbalance to accelerate OA progression.

Resumption of school after lockdown in COVID-19 pandemic: Three case reports.

BACKGROUND: Students in the 9th grade of junior high school in Changsha were under a 75 d lockdown due to the coronavirus disease 2019 (COVID-19) pandemic. After the resumption of school post-lockdown, the 9th grade students in Changsha faced the entrance physical examination test for senior high school. CASE SUMMARY: We report on 3 cases of occult fracture on the same site in adolescents of the same grade since resumption of school after the lockdown from the COVID-19 pandemic. Three students in the 9th grade of junior high school who were facing the physical examination in 2 wk were diagnosed with an occult fracture of the distal femur. CONCLUSION: It is recommended that the students, parents, education providers and policy makers should all pay attention to the physical exercise of students when the resumption of school after lockdown occurs and they should be aware of occult fractures when the adolescents have pain after physical exercise.

Comparison of mid-term clinical results between lag screw fixation and Kirschner wire fixation after close reduction in adolescent triplane distal tibia epiphyseal fracture.

OBJECTIVE: To compare the mid-term clinical results of lag screw and Kirschner wire fixation(KWF) for close reduction in triplane distal tibia epiphyseal fracture. METHODS: A retrospective analysis of 25 cases of triplane fractures of the distal tibia treated in our department from Jan 2017 to Dec 2019 was performed, Lag screw fixation(LSF) was used in 14 cases and Kirschner wire fixation in 11 cases, the clinical results were evaluated by premature epiphyseal closure(PPC) rate, the American Orthopaedic Foot and Ankle Score (AOFAS) Ankle-hindfoot foot scoring system, the lateral distal tibial angle (LDTA) from X-ray. RESULTS: All the 25 children were followed up for a mean of 34(ranging 26-52) months. AOFAS scores improved from a mean of 33(ranging 29-43) pre-op, to 82(ranging 77-88) at three month follow up, to 92 (ranging 88-98) at last follow-up in all 25 cases. Till last follow up there was no cases premature physeal closure in LSF group but 4 cases in KWF group, LDTA in both groups at last follow up shows no ankle varus or valgus deformity, and the ankle joint function was not limited in all cases. CONCLUSION: Lag screw and Kirschner wire fixation methods can both achieve good clinical effects for triplane distal tibia epiphyseal fracture. Lag screw fixation provide lower PPC rate but Kirschner wire fixation save one anesthesia and surgery.

CircKIF4A enhances osteosarcoma proliferation and metastasis by sponging MiR-515-5p and upregulating SLC7A11.

BACKGROUND: Circular RNAs (circRNAs) are forms of non-coding RNAs that have crucial roles in regulation of various biological processes of several malignant tumors. circKIF4A is closely associated with malignant progression of a variety of cancers. However, the molecular mechanisms as well as roles of circKIF4A in osteosarcoma (OS) have not yet been clearly elucidated. METHODS: We evaluated the expression of circKIF4A in OS. Colony-formation, cell counting kit-8 (CCK-8), transwell and mice metastasis model assays were done to explore the roles of circKIF4A in vitro and in vivo. TargetScan database, double luciferase, quantitative reverse transcription polymerase chain reaction analysis (RT-qPCR), and RNA immunoprecipitation (RIP) were done to investigate the associated molecular mechanisms. RESULTS: In both OS cells and tissues, circKIF4A (hsa_circ_0007255) was found to be upregulated. In vitro and in vivo, circKIF4A knockdown markedly suppressed OS proliferation as well as metastasis. circKIF4A enhanced OS growth as well as metastasis by sponging miR-515-5p and by upregulating SLC7A11. CONCLUSIONS: We identified the biological significance of the circKIF4A-miR-515-5p-SLC7A11 axis in OS cell proliferation and metastasis, which is important in OS monitoring and treatment. More studies on circKIF4A will inform on the diagnostic markers for early OS screening.

Synovial chondromatosis of the hip joint in a 6 year-old child: A case report.

BACKGROUND: Synovial chondromatosis (SC) is a rare benign lesion first reported by Ambrose Pare in 1558. It is most common in the knee joint, followed by the hip joint and elbow joint. It is characterized by the presence of multiple pearl-like osteochondral bodies in the joint. The incidence in children is extremely low. CASE SUMMARY: We report a 6-year-old Chinese boy who presented to our hospital with left hip joint pain and claudication for more than one year. We performed total surgical resection of SC tissue in the left hip. A good prognosis was confirmed at the 6-wk follow-up. Pain and swelling symptoms were totally relieved, range of motion of his left hip returned to normal, and there was no clinical evidence of lesion recurrence at last follow-up. Our case is the youngest reported patient with SC occurring in the hip. CONCLUSION: SC is a rare disease and can be easily misdiagnosed. When we encounter children with hip pain and claudication, increased vigilance and a comprehensive physical examination and imaging examination should be considered, in order to avoid misdiagnosis and delayed treatment in patients.

Toll-Like Receptor 3 Deficiency Leads to Altered Immune Responses to Chlamydia trachomatis Infection in Human Oviduct Epithelial Cells.

Reproductive tract pathology caused by Chlamydia trachomatis infection is an important global cause of human infertility. To better understand the mechanisms associated with Chlamydia-induced genital tract pathogenesis in humans, we used CRISPR genome editing to disrupt Toll-like receptor 3 (TLR3) function in the human oviduct epithelial (hOE) cell line OE-E6/E7 in order to investigate the possible role(s) of TLR3 signaling in the immune response to Chlamydia Disruption of TLR3 function in these cells significantly diminished the Chlamydia-induced synthesis of several inflammation biomarkers, including interferon beta (IFN-ß), interleukin-6 (IL-6), interleukin-6 receptor alpha (IL-6Rα), soluble interleukin-6 receptor beta (sIL-6Rß, or gp130), IL-8, IL-20, IL-26, IL-34, soluble tumor necrosis factor receptor 1 (sTNF-R1), tumor necrosis factor ligand superfamily member 13B (TNFSF13B), matrix metalloproteinase 1 (MMP-1), MMP-2, and MMP-3. In contrast, the Chlamydia-induced synthesis of CCL5, IL-29 (IFN-λ1), and IL-28A (IFN-λ2) was significantly increased in TLR3-deficient hOE cells compared to their wild-type counterparts. Our results indicate a role for TLR3 signaling in limiting the genital tract fibrosis, scarring, and chronic inflammation often associated with human chlamydial disease. Interestingly, we saw that Chlamydia infection induced the production of biomarkers associated with persistence, tumor metastasis, and autoimmunity, such as soluble CD163 (sCD163), chitinase-3-like protein 1, osteopontin, and pentraxin-3, in hOE cells; however, their expression levels were significantly dysregulated in TLR3-deficient hOE cells. Finally, we demonstrate using hOE cells that TLR3 deficiency resulted in an increased amount of chlamydial lipopolysaccharide (LPS) within Chlamydia inclusions, which is suggestive that TLR3 deficiency leads to enhanced chlamydial replication and possibly increased genital tract pathogenesis during human infection.

Long non-coding RNA MEG3 inhibits chondrogenic differentiation of synovium-derived mesenchymal stem cells by epigenetically inhibiting TRIB2 via methyltransferase EZH2.

Osteoarthritis (OA) is a highly prevalent skeletal disease. Mesenchymal stem cell-derived cartilage tissue engineering is a clinical method used for OA treatment. Investigations on the molecular regulatory mechanisms of the chondrogenic differentiation of synovium-derived mesenchymal stem cells(SMSCs) will help promote its clinical applications. In this study, bioinformatics analysis from three different databases indicated that the long non-coding RNA (lncRNA) MEG3 may regulate the chondrogenic differentiation of SMSCs by targeting TRIB2. We then performed assays and found that both knockdown of MEG3 or overexpression of TRIB2 can stimulate the chondrogenic differentiation of SMSCs and increase Col2A1 and aggrecan expression. Knockdown of MEG3 can induce the expression of TRIB2; conversely, overexpression of MEG3 can inhibit the expression of TRIB2. Futhermore, knockdown of the TRIB2 can rescue the MEG3 silencing-mediated promotion of chondrogenic differentiation. Moreover, RNA immunoprecipitation(RIP) and RNA pull-down assays demonstrated that MEG3 can interact with EZH2, thus recruiting it to induce H3K27me3, which promotes the methylation of TRIB2 by binding with the promoter of TRIB2 in SMSCs. Additionally, EZH2 silencing significantly rescued the MEG3 overexpression-mediated inhibition of TRIB2 expression and chondrogenic differentiation of SMSCs. Taken together, these data indicated that MEG3 regulates chondrogenic differentiation by inhibiting TRIB2 expression through EZH2-mediated H3K27me3.

MicroRNA-29a suppresses the invasion and migration of osteosarcoma cells by regulating the SOCS1/NF-κB signalling pathway through negatively targeting DNMT3B.

The present study aimed to investigate the roles of the microRNA­29a/DNA methyltransferase 3B/suppressor of cytokine signalling 1 (miR­29a/DNMT3B/SOCS1) axis in the invasion and the migration of osteosarcoma (OS). The expression levels of miR­29a, DNMT3B and SOCS1 were determined in tissue samples and OS cell lines by reverse transcription­quantitative polymerase chain reaction (PCR). Apoptosis was measured using flow cytometry analysis. Transwell and wound healing assays were conducted to measure the invasion and migration abilities of OS cells, respectively. A dual­luciferase reporter assay was also conducted to determine the interaction between DNMT3B and miR­29a, while methylation­specific PCR was used to detect the methylation of SOCS1. Western blotting was performed to determine the protein levels of DNMT3B and SOCS1, as well as the levels of proteins associated with epithelial­mesenchymal transition (EMT), apoptosis and the nuclear factor (NF)­κB signalling pathway. The results demonstrated that miR­29a and SOCS1 were downregulated, and DNMT3B was upregulated in both OS tissues and cell lines. The expression of miR­29a and SOCS1 was found to be associated with advanced clinical stage and distant metastasis. In addition, the dual­luciferase reporter assay revealed that DNMT3B was a direct target of miR­29a. Overexpression using miR­29a mimics decreased DNMT3B expression and the methylation level of SOCS1, which resulted in the upregulation of SOCS1 in U2OS and MG­63 cells, while miR­29a inhibition led to the opposite results. Transfection with miR­29a mimics also promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells, while it markedly reduced the nuclear translocation of p65 and IκB­α degradation. Treatment with 5­aza­2'­deoxycytidine worked together with miR­29a mimics to synergistically enhance the aforementioned effects. By contrast, the effects induced by miR­29a were partly reversed upon co­transfection with SOCS1 siRNA. In conclusion, miR­29a promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells via inhibition of the SOCS1/NF­κB signalling pathway by directly targeting DNMT3B.

TLR3 deficiency exacerbates the loss of epithelial barrier function during genital tract Chlamydia muridarum infection.

PROBLEM: Chlamydia trachomatis infections are often associated with acute syndromes including cervicitis, urethritis, and endometritis, which can lead to chronic sequelae such as pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy, and tubal infertility. As epithelial cells are the primary cell type productively infected during genital tract Chlamydia infections, we investigated whether Chlamydia has any impact on the integrity of the host epithelial barrier as a possible mechanism to facilitate the dissemination of infection, and examined whether TLR3 function modulates its impact. METHOD OF STUDY: We used wild-type and TLR3-deficient murine oviduct epithelial (OE) cells to ascertain whether C. muridarum infection had any effect on the epithelial barrier integrity of these cells as measured by transepithelial resistance (TER) and cell permeability assays. We next assessed whether infection impacted the transcription and protein function of the cellular tight-junction (TJ) genes for claudins1-4, ZO-1, JAM1 and occludin via quantitative real-time PCR (qPCR) and western blot. RESULTS: qPCR, immunoblotting, transwell permeability assays, and TER studies show that Chlamydia compromises cellular TJ function throughout infection in murine OE cells and that TLR3 deficiency significantly exacerbates this effect. CONCLUSION: Our data show that TLR3 plays a role in modulating epithelial barrier function during Chlamydia infection of epithelial cells lining the genital tract. These findings propose a role for TLR3 signaling in maintaining the integrity of epithelial barrier function during genital tract Chlamydia infection, a function that we hypothesize is important in helping limit the chlamydial spread and subsequent genital tract pathology.