KLF11 protects chondrocytes via inhibiting p38 MAPK signaling pathway.

OBJECTIVE: The purpose of this study was to explore the effects of Kruppel like factors 11 (KLF11) on oxidative stress, apoptosis, and endoplasmic reticulum stress (ERS) in osteoarthritis (OA) and its mechanism. PATIENTS AND METHODS: Human articular cartilage tissue was used to study the correlation between KLF11 and OA. Furthermore, human chondrocytes were used to explore the effects of KLF11 on oxidative stress, apoptosis, and ERS in chondrocytes by overexpressing KLF11 and using the OA inducer IL-1ß. The p38MAPK signaling pathway agonist P79350 was used to study the effect of KLF11 on the p38 MAPK signaling pathway. RESULTS: Articular cartilage tissue in OA patients and IL-1ß-induced chondrocytes expressed higher KLF11. Overexpression of KLF11 significantly reduced oxidative stress levels, apoptosis levels, and activity of ERS-related pathways in chondrocytes. Moreover, P79350 attenuated the protective effect of KLF11 on chondrocytes by activating the p38MAPK signaling pathway. CONCLUSIONS: KLF11 protects against OA by inhibiting oxidative stress, apoptosis, and ERS in chondrocytes by inhibiting p38MAPK signaling pathway.

MiR-143-3p regulates early cartilage differentiation of BMSCs and promotes cartilage damage repair through targeting BMPR2.

OBJECTIVE: The aim of this study was to explore the role of microRNA-143-3p (miR-143-3p) in cartilage injury, and to investigate the possible underlying mechanism. MATERIALS AND METHODS: A chondrogenic differentiation cell model was established in bone marrow mesenchymal stem cells (BMSCs). The mRNA expression levels of runt-related transcription factor 2 (RUNX2), miR-143-3p and bone morphogenetic protein 2 (BMPR2) in BMSCs were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) after 0 d, 5 d and 10 d, respectively. Mesenchymal stem cells (MSCs) were transfected with miR-143-3p mimics and its control in accordance with the liposome method. Alcian blue colorimetric assay was used to evaluate proteoglycan deposition of MSCs. Meanwhile, qRT-PCR and Western blot were performed to analyze the expression levels of ACAN and COL2A1. Luciferase reporter gene assay was applied to verify the binding status of miR-143-3p and BMPR2 3'UTR. Also, proteoglycan deposition and the expression of ACAN and COL2A1 were detected after simultaneous transfection of miR-143-3p mimics and BMPR2 overexpression plasmid. RESULTS: 0 d, 5 d and 10 d after inducing cartilage differentiation, the mRNA expression levels of RUNX2 and BMPR2 were markedly increased. However, the expression level of miR-143-3p was significantly decreased with the prolongation of induction period. After transfection with miR-143-3p mimics, the level of miR-143-3p in MSCs was remarkably increased. Alcian blue colorimetric assay and staining assay showed that the deposition of proteoglycans in the mimics group was significantly lower than that of the control group. Meanwhile, after overexpressing miR-143-3p, the levels of cartilage differentiation marker proteins including ACAN and COL2A1 were remarkably reduced. Luciferase report gene assay indicated that miR-143-3p could negatively regulate BMPR2 by binding to its 3'UTR. In addition, overexpression of BMPR2 could strikingly reverse the above effects of overexpressed miR-143-3p. CONCLUSIONS: During chondrogenic differentiation, the level of miR-143-3p was decreased. Moreover, miR-143-3p could regulate the differentiation process by targeting BMPR2 in BMSCs.

STEEL participates in fracture healing through upregulating angiogenesis-related genes by recruiting PARP 1.

OBJECTIVE: To explore the effect of STEEL on fracture healing and its underlying mechanism. PATIENTS AND METHODS: A total of 31 patients with long bone fracture and who received reoperation because of bone nonunion, delayed union or healing disorder in the Wuxi Nine Hospital Affiliated to Soochow University from July 2016 to February 2018 were selected. The bone callus at the fracture site was collected from each patient during the reoperation. QRT-PCR (Quantitative Real-Time Polymerase Chain Reaction) was used to detect STEEL expression in the callus tissues of the treatment group (bone nonunion or delayed union) and the control group. In addition, we measured the number of blood vessels in the fracture tissues by immunohistochemistry. After the construction of tibial fracture model in mice, STEEL expression and the total number of blood vessels in the treatment group (sawing treatment) and the control group (sham operation) were detected, respectively. For in vitro experiments, CCK-8 (cell counting kit-8) assay was performed to detect cell proliferation after knockdown or overexpression of STEEL in the vascular endothelial cells. The binding condition of STEEL and its interacting proteins were detected by RIP (RNA binding protein immunoprecipitation), and the binding of PARP 1 [poly (ADP-ribose) polymerase 1] with gene promoter was observed by ChIP (chromatin immunoprecipitation assay). Western blot was used to detect the expression level of VEGF (vascular endothelial growth factor). RESULTS: STEEL expression and the vascular density in the callus tissues of the treatment group were significantly lower than those of the control group. Downregulated STEEL remarkably decreased the proliferation ability of HUVEC cells. Meanwhile, the vascular density was also significantly decreased in mice with a tibial fracture. Overexpressed STEEL obtained the opposite results. STEEL could interact with PARP 1 to regulate expressions of downstream genes. Moreover, STEEL could also promote angiogenesis by elevating VEGF expression. CONCLUSIONS: We showed that STEEL expression could partly represent the angiogenesis of fracture sites. Moreover, it promoted angiogenesis by elevating VEGF expression.

Correlations between CXCL13, IL-24 genes and wrist arthritis.

OBJECTIVE: To investigate the relationship between B lymphocyte chemokine 1 (CXCL13) and interleukin-24 (IL-24) gene and wrist arthritis. PATIENTS AND METHODS: A total of 122 cases of patients with wrist arthritis treated in our hospital from May 2013 to April 2016 were randomly selected as wrist arthritis group, while 120 normal subjects were selected as normal control group. Venous blood was collected from all patients in normal control group and wrist arthritis group, respectively. Rheumatoid factor (RF), human C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) in venous blood were measured. The visual analogue scale (VAS) score was used to statistically analyze the pain of subjects in normal control and wrist arthritis groups; the wrist flexion and extension activities of subjects in normal control group and wrist arthritis group were measured. The expressions of CXCL13 and IL-24 mRNA in synovial tissue of normal control group and wrist arthritis group were detected by reverse transcription-polymerase chain reaction (RT-PCR). Western blotting was used to detect the expressions of CXCL13 and IL-24 in normal control group and wrist arthritis group. RESULTS: The levels of CRP, RF, and ESR in the normal control group were within the normal range, but the levels of CRP, RF, and ESR in the wrist arthritis group were significantly higher than those in the normal control group. VAS scores and joint flexion extension activities in the normal control group were at normal levels. The VAS score of wrist arthritis group was significantly higher than that of the normal control group, and the joint flexion extension activities were significantly lower than that in the normal control group. The results of RT-PCR showed that the expression of CXCL13 mRNA in synovial tissue of wrist arthritis was significantly higher than that in the normal control group, while the expression of IL-24 mRNA in synovial tissue of wrist arthritis was significantly lower than that in normal control tissues. Western blotting showed that the expression of CXCL13 in synovial tissue of wrist arthritis was significantly higher than that in the normal control group, while the expression of IL-24 in synovial tissue of wrist arthritis was significantly lower than that in normal control groups. Analysis of variance showed that the expressions of CXCL13 and IL-24 in the normal control group and wrist arthritis group had statistically significant differences (p<0.01). CONCLUSIONS: The abnormal expressions of CXCL13 and IL-24 are closely related to the occurrence and development of wrist arthritis. This study shows that CXCL13 and IL-24 have important research values in wrist arthritis. CXCL13 and IL-24 expressions can be used as new indicators of the diagnosis and treatment of wrist arthritis.

Minimally invasive percutaneous plate osteosynthesis for distal radius fractures with long-segment metadiaphyseal comminution.

INTRODUCTION: Distal radius fractures with both metaphyseal and diaphyseal comminution are commonly encountered injuries due to high-energy trauma. However, effectively treating patients with this disease remains challenging for the surgeon. HYPOTHESIS: The goal of this study was to evaluate the outcomes of minimally invasive percutaneous plate osteosynthesis (MIPPO) technique for distal radius fractures with long-segment metadiaphyseal comminution. MATERIAL AND METHODS: Nine patients with distal radius fractures involving long-segment metadiaphyseal comminution were treated with MIPPO from June 2011 to May 2012. Radiograph index, the range of motion of the wrist and forearm, grip strength, the Disabilities of the Arm, Shoulder, and Hand (DASH) score were assessed at final follow-up. Additionally, time to bone healing, time to return to work or activity, and postoperative complications were also recorded. RESULTS: All nine fractures healed by 13±1.3 weeks postoperatively. At an average follow-up of 15.9±3.6 months, the radiographs revealed a mean radial inclination of 18.2±2.7°, a mean volar tilt of 10.7±3.2°, and a radial shortening of 2.3±1.0mm. Nine patients had excellent wrist function according to the DASH score, range of motion, and grip strength. Except one patient experienced delayed healing of the distal incision, no complications occurred. All patients resumed work or activity within 16.2±1.9 weeks. DISCUSSION: Volar MIPPO is a safe and effective surgical treatment method for distal radius fractures with long-segment metadiaphyseal comminution, with few potential complications. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.