Osteoarthritis (OA) is a type of degenerative joint disease that affects the health of the elderly. OA is characterized by articular cartilage degradation and joint inflammation. The present study aimed to investigate the role and mechanism of microRNA-let-7a (Let-7a) in OA by examining its role in lipopolysaccharide (LPS)-induced cartilage inflammatory injury in ATDC5 cells. ATDC5 cells were treated with various concentrations of LPS. The present results suggested that 5 and 10 µg/ml LPS significantly inhibited ATDC5 cell viability, and 5 µg/ml LPS was selected for further experiments. Reverse transcription-quantitative PCR (RT-qPCR) results suggested that treatment with LPS significantly induced the expression levels of multiple inflammatory factors, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and IL-8, and increased the expression level of Let-7a in ATDC5 cells. IL-6 receptor (IL-6R) was identified to be a direct target of Let-7a using TargetScan and a dual-luciferase reporter assay. Subsequently, Cell Counting Kit-8 and flow cytometry analyses identified that Let-7a inhibitor could significantly promote cell viability and reduce cell apoptosis in ATDC5 cells treated with LPS, and these effects could be reversed by transfection with small interfering (si)RNA-IL-6R. ELISA was used to examine the expression of inflammatory factors in ATDC5 cells following treatment with LPS. Additionally, RT-qPCR and western blotting were performed to detect the mRNA and protein expression level of IL-6R and STAT3. The present results suggested that Let-7a inhibitor significantly reduced the expression level of TNF-α, IL-1β, IL-6 and IL-8 in ATDC5 cells, and this effect was reversed by transfecting siRNA-IL-6R. Moreover, RT-qPCR and western blot assay results suggested that Let-7a inhibitor significantly increased the expression level of IL-6R and phosphorylated STAT3, and these effects could be reversed by siRNA-IL-6R. Collectively, Let-7a inhibitor increased cell proliferation, reduced apoptosis and inhibited inflammatory response in ATDC5 cells treated with LPS. The present study provided a new potential therapeutic target for OA treatment.
Dysfunction of bone marrow mesenchymal stem cells (BMSCs) is recognized critical in bone deteriorations of osteoporosis. However, the specific mechanisms that determine the fate of BMSCs remain elusive. MicroRNA-133a (miR-133a), a highly conserved microRNA, was investigated under both in vitro and in vivo conditions. In the in vitro study, cell proliferation, cell apoptosis, and osteoblast/adipocyte differentiation of BMSCs as a result of overexpression or knockdown of miR-133a was investigated. In the in vivo study, the ovariectomy (OVX) model was applied on mice, with further treatment of the models with BMSC-specific miR-133a antagomir through femur intramedullary injection. Microcomputed tomography scanning and histological analysis of the proximal and middle femur were performed to evaluate the morphological changes. The results revealed that overexpression of miR-133a suppressed cell proliferation, cell viability, and osteoblast differentiation of BMSCs, but increased adipocyte differentiation. We also found that FGFR1, an important upstream regulator of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signal pathway, was a major target of miR-133a. We also recorded that BMSC-specific knockdown of miR-133a attenuates bone loss in OVX mice. Our study suggested that miR-133a played an important role in maintaining the viability and balance between osteoblast and adipocyte differentiation of BMSCs through the MAPK/ERK signaling pathway by targeting FGFR1.
Background Postmenopausal osteoporosis is one of the most common types of osteoporosis that women suffer from. Studies involving molecular mechanisms for designing better therapeutic strategies for postmenopausal osteoporosis are still rare. The present study investigates the role of miR-125b in postmenopausal osteoporosis. Methods Microarray analysis was done to screen the gene database. Tissue samples of postmenopausal women were collected to study the miRNA profiles. MC3T3-E1 cells were used and were submitted for transfection. CCK-8 assay was done to check the viability of cells, whereas toxicity was done by lactate dehydrogenase assay kit. TargetScan was done to target genes of miR-125b followed by confirmation by Luciferase reporter assay. For animal studies a rat model of ovariectomized rats was created. Bone mineral density and biomechanics were measured by densitometer. The mRNA levels were assessed by qRT-PCR and proteins by Western blot assay. Results miR-125b was over-expressed in human osteoporosis samples. In vitro studies suggested that miR-125b suppressed the cell viability and promoted release of LDH, it also enhanced the RANKL/OPG ratio and suppressed levels of BMP2 and Runx2. Bioinformatics identified TRAF6 as a potential target of miR-125b, further confirmed by luciferase assay, also miR-125b negatively regulated the levels of TRAF6 gene in osteoporosis bones involving the JAK2/STAT3 cascade. In the rat model, miR-125b decreased the bone mineral density and biomechanical parameters in bones by altering the TRAF6 gene involving the JAK2/STAT3 pathway. Conclusion The outcomes suggested that miR-125b was responsible for the development of postmenopausal osteoporosis and promoted its progression by the TRAF6 gene via the JAK2/STAT3 pathway.
Background. The treatment of vertical femoral neck fractures in young patients remains a challenge. This study is aimed at comparing ordinary cannulated compression screw (OCCS) and double-head cannulated compression screw (DhCCS) fixation in vertical femoral neck fractures both clinically and biomechanically. Materials and Methods. Clinically, the radiographs of 81 patients with Pauwel’s III femoral neck fractures, including 54 fractures fixed with three parallel OCCSs and 27 fractures fixed with three parallel DhCCSs, were reviewed retrospectively. Complications consisting of fixation failure (screw loosening, obvious fracture displacement, varus deformity, or femoral neck shortening), bony nonunion, and avascular necrosis (AVN) were determined. Biomechanically, twenty synthetic femur models of vertical femoral fractures with an 80° Pauwel’s angle were divided into two groups and subsequently fixed with three parallel OCCSs or DhCCSs. All specimens were tested for axial stiffness, load to 5 mm displacement, and a maximum load to failure with a loading rate of 2 mm/min. Results. Clinically, 22 fractures in the OCCS group experienced fixation failure, including 19 screw loosening, 18 femoral neck shortening, 14 varus deformities, and 8 obvious fracture displacements, whereas only 4 fractures experienced fixation failure in the DhCCS group, including 3 screw loosening, 3 femoral neck shortening, 3 varus deformities, and 1 obvious fracture displacement. Additionally, 11 fractures in the OCCS group exhibited nonunion, whereas only 3 in the DhCCS group exhibited nonunion. Nine fractures with AVN were noted in the OCCS group, whereas only 1 was observed in the DhCCS group. Biomechanically, the axial stiffness of the DhCCS group was greater than that of the OCCS group ( 154.9 ± 6.81 vs. 128.1 ± 7.41 N/mm), and the load to 5 mm displacement was also significantly greater in the DhCCS group ( 646.1 ± 25.87 vs. 475.8 ± 21.46 N). Moreover, the maximum load to failure in the DhCCS group exhibited significant advantages compared with that of the OCCS group ( 1148 ± 39.47 vs. 795.9 ± 51.39 N). Conclusion. Our results suggested that using three DhCCSs improved the outcome of vertical femoral neck fractures compared to three OCCSs, offering a new choice for the treatment of femoral neck fracture.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.