lncTIMP3 promotes osteogenic differentiation of bone marrow mesenchymal stem cells via miR-214/Smad4 axis to relieve postmenopausal osteoporosis.

Promoting the balance between bone formation and bone resorption is the main therapeutic goal for postmenopausal osteoporosis (PMOP), and bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation plays an important regulatory role in this process. Recently, several long non-coding RNAs (lncRNAs) have been reported to play an important regulatory role in the occurrence and development of OP and participates in a variety of physiological and pathological processes. However, the role of lncRNA tissue inhibitor of metalloproteinases 3 (lncTIMP3) remains to be investigated. The characteristics of BMSCs isolated from the PMOP rat model were verified by flow cytometry assay, alkaline phosphatase (ALP), alizarin red and Oil Red O staining assays. Micro-CT and HE staining assays were performed to examine histological changes of the vertebral trabeculae of the rats. RT-qPCR and western blotting assays were carried out to measure the RNA and protein expression levels. The subcellular location of lncTIMP3 was analyzed by FISH assay. The targeting relationships were verified by luciferase reporter assay and RNA pull-down assay. The trabecular spacing was increased in the PMOP rats, while ALP activity and the expression levels of Runx2, Col1a1 and Ocn were all markedly decreased. Among the RNA sequencing results of the clinical samples, lncTIMP3 was the most downregulated differentially expressed lncRNA, also its level was significantly reduced in the OVX rats. Knockdown of lncTIMP3 inhibited osteogenesis of BMSCs, whereas overexpression of lncTIMP3 exhibited the reverse results. Subsequently, lncTIMP3 was confirmed to be located in the cytoplasm of BMSCs, implying its potential as a competing endogenous RNA for miRNAs. Finally, the negative targeting correlations of miR-214 between lncTIMP3 and Smad4 were elucidated in vitro. lncTIMP3 may delay the progress of PMOP by promoting the activity of BMSC, the level of osteogenic differentiation marker gene and the formation of calcium nodules by acting on the miR-214/Smad4 axis. This finding may offer valuable insights into the possible management of PMOP.

Wumiti T ，Wang L ，Xu B ，Ma Y ，Zhu Y ，Zuo X ，Qian W ，Chu X ，Sun H ... -  《-》

Osteoking inhibits apoptosis of BMSCs in osteoporotic rats via PI3K/AKT signaling pathway.

In China, Osteoking is a commonly used treatment and preventive measure for osteoporosis. The pathophysiology of osteoporosis is closely associated with apoptosis; however, it remains unclear whether the role of Osteoking in promoting bone formation is linked to apoptosis. This study aims to investigate whether Osteoking inhibits apoptosis of BMSCs in osteoporotic rats via the PI3K/AKT signaling pathway and to conduct a detailed exploration of this mechanism. The goal is to provide a theoretical basis for the clinical application of Osteoking in osteoporosis treatment. A rat model of osteoporosis was established through bilateral ovariectomy (OVX), followed by treatment with Osteoking. After ten weeks of therapy, BMD was evaluated. The biomechanics of the left tibia were measured, the left femur was sequenced, and the right tibia was stained using histomorphometric and Masson's staining methods. Peripheral serum was collected to measure bone-related markers, including E2, PINP, and CTX. RNA-Seq results were verified using the remaining bone samples. Comparative analysis demonstrated the efficacy of Osteoking in treating osteoporosis and provided preliminary insights into the underlying mechanisms. Primary BMSCs were cultured using bone marrow apposition. CCK8 assays were conducted to screen the intervention conditions of Osteoking and LY294002. Various concentrations of Osteoking-containing serum and LY294002 were tested separately to determine the optimal intervention concentration for drug delivery. The impact of Osteoking on lipid formation was also evaluated. Following treatment of BMSCs from OVX rats with Sham serum, OVX serum, OVX + LY294002 serum, and Osteoking + LY294002 serum, the expression of PI3K/AKT/mTOR, osteogenesis-related regulatory factors, and apoptosis-related regulatory factors was assessed. Flow cytometry was employed to evaluate apoptosis in BMSCs. Osteoking significantly improved whole-body BMD and bone biomechanical indices in OVX rats. It also significantly elevated the serum levels of E2 and PINP while reducing the level of CTX, which significantly improved bone microstructure and promoted new bone formation. RNA-seq analysis indicated that the therapeutic mechanism involved the PI3K/AKT signaling pathway. Osteoking increased the expression of RUNX2 and decreased the expression of PPAR-γ, a marker of lipogenesis, in OVX rats. Extraction of BMSCs for subsequent studies revealed a significant reduction in proliferation and osteogenic differentiation, along with an increase in lipogenic differentiation, in the OVX group. Osteoking treatment inhibited the expression of PPAR-γ and increased the expression of RUNX2 in BMSCs. Additionally, Osteoking reversed the LY294002-mediated inhibition of PI3K/AKT/mTOR signaling pathway activation, increased the expression of the apoptosis-protecting protein Bcl2, and decreased the expression of apoptosis-associated proteins Caspase3 and Bax. Osteoking markedly improved bone microstructure, biomechanics, and bone density in OVX rats. Osteoking-containing serum reversed the imbalance in lineage differentiation in OVX rats, characterized by reduced osteogenic differentiation and increased lipid differentiation of BMSCs. Furthermore, Osteoking-containing serum significantly increased BMSC proliferation and prevented apoptosis in OVX rats through the PI3K/AKT signaling pathway.

Huang G ，Yin W ，Zhao X ，Xu M ，Wang P ，Li R ，Zhou L ，Tang W ，Jiao J ... -  《-》

Long non-coding RNA-H19 stimulates osteogenic differentiation of bone marrow mesenchymal stem cells via the microRNA-149/SDF-1 axis.

Bone defects resulting from non-union fractures or tumour resections are common clinical problems. Long non-coding RNAs (lncRNAs) are reported to play vital roles in stem cell differentiation. The aim of this study was to elucidate the role of lncRNA-H19 in osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs). Following the establishment of an osteogenic differentiation model in rats, the expression of H19, microRNA-149 (miR-149) and stromal cell-derived factor-1 (SDF-1) was measured by RT-qPCR. Thereafter, BMMSCs were isolated from rats and treated with a series of mimic, inhibitor or siRNA. SDF-1 expression, alkaline phosphatase (ALP) activity and osteocalcin (OCN) content were detected. The mineralized and calcified nodules were assessed by alizarin red S and Von Kossa staining. BMMSC surface markers were detected by flow cytometry. Western blot analysis was used to measure the expression of ALP, OCN, runt-related transcription factor 2 (RUNX2) and osterix (OSX) proteins. Lastly, dual-luciferase reporter gene assay and RNA immunoprecipitation were applied to verify the relationship of H19, miR-149 and SDF-1. Overexpressed H19 and SDF-1 and poorly expressed miR-149 were found in rats with osteogenic differentiation. H19 increased SDF-1 expression by binding to miR-149. H19 enhanced ALP activity, OCN content, calcium deposit and ALP, OCN, RUNX2 and OSX protein expression of BMMSCS by up-regulating SDF-1 via binding to miR-149. Taken together, up-regulated H19 could promote the osteogenic differentiation of BMMSCs by increasing SDF-1 via miR-149.

Li G ，Yun X ，Ye K ，Zhao H ，An J ，Zhang X ，Han X ，Li Y ，Wang S ... -  《-》

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

《Jove-Journal of Visualized Experiments》

CircCOX6A1 suppresses osteogenic differentiation and aggravates osteoporosis via miR-512-3p/DYRK2 axis.

Osteoporosis (OP), characterized by compromised bone integrity and increased fracture risk, poses a significant health challenge. Circular RNAs (circRNAs) have emerged as crucial regulators in various pathophysiological processes, prompting investigation into their role in osteoporosis. This study aimed to elucidate the involvement of circCOX6A1 in OP progression and understand its underlying molecular mechanisms. The primary objective was to explore the impact of circCOX6A1 on bone marrow-derived mesenchymal stem cells (BMSCs) and its potential interactions with miR-512-3p and DYRK2. GSE161361 microarray analysis was employed to assess circCOX6A1 expression in OP patients. We utilized in vitro and in vivo models, including BMSC cultures, osteogenic differentiation assays, and an OVX-induced mouse model of OP. Molecular techniques such as quantitative RT-PCR, western blotting, and functional assays like alizarin red staining (ARS) were employed to evaluate circCOX6A1 effects on BMSC proliferation, apoptosis, and osteogenic differentiation. The interaction between circCOX6A1, miR-512-3p, and DYRK2 was investigated through dual luciferase reporter assays, RNA immunoprecipitation, and RNA pull-down assays. CircCOX6A1 was found to be upregulated in osteoporosis patients, and its expression inversely correlated with osteogenic differentiation of BMSCs. CircCOX6A1 knockdown enhanced osteogenic differentiation, as evidenced by increased mineralized nodule formation and upregulation of osteogenic markers. In vivo, circCOX6A1 knockdown ameliorated osteoporosis progression in OVX mice. Mechanistically, circCOX6A1 acted as a sponge for miR-512-3p, subsequently regulating DYRK2 expression. This study provides compelling evidence for the role of circCOX6A1 in osteoporosis pathogenesis. CircCOX6A1 negatively regulates BMSC osteogenic differentiation through the miR-512-3p/DYRK2 axis, suggesting its potential as a therapeutic target for mitigating OP progression.

He D ，Zheng S ，Cao J ，Deng J ，Ding R ，Xu Y ，Cheng X ... -  《-》