Therapeutic potential of microRNA in tendon injuries

FTVI promotes osteogenic differentiation of bone marrow mesenchymal stem cells through LncRNA HIF1A-AS2

OBJECTIVES

The treatment of bone defects caused by trauma and pathological factors was a common problem in clinic. Extracorporeal fucosylation has been proved to promote osteogenic differentiation. Nevertheless, the biological processes by which they promote osteogenesis are currently poorly understood. Long non-coding RNAs (lncRNAs) were essential for controlling osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). This study aimed to investigate whether LncRNA HIF1A-AS2 could mediate the effects of alpha-(1,3)-fucosyltransferase VI (FTVI) on osteogenic differentiation of BMSCs.

METHODS

Rat BMSCs with lncRNA HIF1A-AS2 interference plasmid or the FTVI overexpression plasmid were co-cultured in osteogenic differentiation medium. The effects of fucosylation modification of FTVI on osteogenic differentiation of BMSCs were examined, with a focus on LncRNA HIF1A-AS2.

RESULTS

FTVI could upregulate HIF1A-AS2, and inhibition of lncRNA HIF1A-AS2 in FTVI- transfected BMSCs could decrease type I collagen (Col I), runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and bone morphogenetic protein 2 (BMP2), vascular endothelial growth factor 165 (VEGF165) proteins expressions which were increased by FTVI. Furthermore, it was discovered that inhibiting lncRNA HIF1A-AS2 decreased the the homing ability of BMSCs demonstrating by antigen contents of HECA452 and CD15s.

CONCLUSIONS

According to these results, the effects of FTVI on osteogenic differentiation of BMSCs depend on the existence of lncRNA HIF1A-AS2. A better understanding of the pathophysiological mechanism of bone defect helped to provide theoretical basis for the reconstruction of bone damage using stem cells in clinic.

LncRNA CRNDE ameliorates bone fracture by regulating cell viability and apoptosis of osteoblasts

BACKGROUND

Delayed healing is a common postoperative complication among fractured patients, imposing an additional financial burden. This research examined the clinical relationship between CRNDE and delayed fracture healing (DFH) and the potential regulatory mechanisms underlying fracture improvement.

METHODS

qRT-PCR was utilized to assess the expression of CRNDE and miR-29a-3p in serum and cellular samples, and to evaluate the expression of genes associated with osteogenic differentiation. The diagnostic and predictive significance of serum CRNDE was analyzed using ROC analysis and logistic regression. Additionally, an hFOB 1.19 osteogenic differentiation model was established. The CCK-8 assay and flow cytometry techniques were used to investigate the effects of silencing CRNDE, as well as the concurrent inhibition of both CRNDE and miR-29a-3p, on the proliferation and apoptosis of hFOB 1.19 cells.

RESULTS

CRNDE was down-regulated, while miR-29a-3p was up-regulated in DFH patients. The serum CRNDE could effectively identify DFH patients and predict the DFH occurrence. In the hFOB 1.19 osteogenic differentiation model, silencing CRNDE led to a significant decrease in the expression of osteogenic differentiation markers, a reduction in the proliferation activity of hFOB 1.19 cells, and an increase in apoptosis. There was a negative regulatory interaction between CRNDE and miR-29a-3p. Concurrently inhibiting the expression of both CRNDE and miR-29a-3p could effectively restore the functional activity of hFOB 1.19 cells.

CONCLUSION

Serum CRNDE holds potential as a biomarker for the diagnosis and prediction of DFH. The sponging effect of CRNDE on miR-29a-3p could ameliorate fracture healing.

LncRNA HCG18 regulates the progression of spinal tuberculosis by modulating the hsa-miR-146a-5p/TGF-β1/SMADs pathway

Spinal tuberculosis is the most common extrapulmonary tuberculosis, characterized by intervertebral disc destruction, which seriously affects people's quality of life. Recent studies have suggested that the TGF-β1/SMADs signaling pathway plays an important regulatory role in the process of intervertebral disc destruction caused by spinal tuberculosis. However, the abnormal TGF-β1/SMADs signaling pathway in spinal tuberculosis is not fully understood. Herein, we found for the first time that HCG18 was significantly upregulated in spinal tuberculosis nucleus pulposus clinical samples and confirmed that HCG18 negatively regulates the proliferation and migration ability of nucleus pulposus cells (NPCs). In vitro experiments further suggest that overexpression of HCG18 can significantly promote TGF-β1/SMADs pathway activity and inhibit proliferation, migration, and apoptosis of NPCs, an effect which can be reversed by overexpressing hsa-miR-146a-5p. On the contrary, knocking down HCG18 yields the opposite result. In vivo experiments suggest that knocking down HCG18 can significantly alleviate the destruction of the nucleus pulposus in rats with spinal tuberculosis by inhibiting the activity of the TGF-β1/SMADs pathway. In summary, our research suggests that HCG18 can promote the progression of spinal tuberculosis by alleviating the inhibitory effect of hsa-miR-146a-5p on the TGF-β1/SMADs pathway. This study provides new insights into the occurrence and development of spinal tuberculosis, as well as new strategies for the prevention and treatment of spinal tuberculosis.

MiRNA-mRNA network in osteoporotic fractures proposes the functional mechanism of hsa-miR-32-3p/TNFSF11 axis

BACKGROUND AND AIMS

This study aimed to construct a miRNA-mRNA network in OF and explored the effect of the hsa-miR-32-3p/TNFSF11 axis on osteoclast function.

METHODS

GSE70318 and GSE74209 datasets were used to filter the differentially expressed miRNAs in OF. Then, the targets of these miRNAs intersected with the disease genes of OF. The target genes were annotated using GO terms and KEGG pathway enrichment analysis. The network for miRNA-gene-top 30 GO terms/top 20 pathways was drawn. Sankey diagrams were drawn for Parathyroid hormone synthesis, secretion, and action pathway (hsa04928) and ossification (GO:0001503) related to osteoporotic fracture. The hsa-miR-32-3p/TNFSF11 axis was selected for expression and functional verification.

RESULTS

A total of 21 differentially expressed miRNAs in OF were obtained by analyzing GSE70318 and GSE74209 datasets. A total of 36 genes were related to OF among the miRNA-targets. The genes were enriched in GO terms and KEGG pathways related to OF. Parathyroid hormone synthesis, secretion, and action pathway (hsa04928) and ossification proposed that the hsa-miR-32-3p/TNFSF11 axis may be involved in OF. The expression level of hsa-miR-32-3p was decreased in patients with low bone mineral density (BMD) and fracture, while the expression level of TNFSF11 mRNA was increased. Hsa-miR-32-3p complementarily bound with TNFSF11. Hsa-miR-32-3p inhibited osteoclast activation, while TNFSF11 promoted osteoclast activation.

CONCLUSIONS

The miRNA-mRNA network in OF proposed the TNFSF11 as a downstream target of hsa-miR-32-3p. The hsa-miR-32-3p/TNFSF11 axis was involved in the regulation of osteoclast activity.

CLINICAL TRIAL NUMBER

Not applicable.

MIR155HG suppresses the osteogenic differentiation of bone marrow mesenchymal stem cells through regulating miR-155-5p and DKK1 expression

BACKGROUND

Increasing evidence has demonstrated that non-coding RNAs, including the lncRNA MIR155HG, are involved in the pathogenesis of postmenopausal osteoporosis (PMOP). In the current study, we studied MIR155HG function in regulation of osteogenic differentiation and tried to reveal the underlying mechanisms.

METHODS

Forty blood samples taken from 20 PMOP patients (PMOP group) and 20 postmenopausal individuals without osteoporosis (control group) were used to compare the contents of MIR155HG and miR-155-5p via RT-PCR. Alizarin red S staining and ALP staining were used to evaluate the osteogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Elevated levels of MIR155HG and miR-155-5p were observed in the blood samples of the PMOP group. Upregulation of MIR155HG resulted in decreased expression of OPN, OSX, ALP, RUNX2 and β-catenin but increased DKK1 expression, together with decreased Alizarin red S + and ALP + staining areas. However, downregulation of DKK1 did not obviously change the above indices induced by MIR155HG upregulation. Further experiments revealed that MIR155HG caused an increase in the expression of miR-155-5p, which also serves as an inhibitor of the osteogenic differentiation of BMSCs through binding to β-catenin. Consistent with DKK1 knockdown, downregulation of miR-155-5p only also did not obviously reverse the repressive effect of MIR155HG on osteoblastic differentiation, but downregulation of DKK1 and miR-155-5p synchronously restored the osteogenic differentiation ability of BMSCs suppressed by MIR155HG overexpression.

CONCLUSION

MIR155HG suppressed the osteoblastic differentiation of BMSCs by regulating miR-155-5p and DKK1 expression. Either inhibition of miR-155-5p and DKK1 or direct suppression of MIR155HG may be effective approaches for treating PMOP.

Molecular features and diagnostic modeling of synovium- and IPFP-derived OA macrophages in the inflammatory microenvironment via scRNA-seq and machine learning

BACKGROUND

Osteoarthritis (OA) is the leading cause of degenerative joint disease, with total joint replacement as the only definitive cure. However, no disease-modifying therapy is currently available. Inflammation and fibrosis in the infrapatellar fat pad (IPFP) contribute to OA onset and progression. However, the cellular composition and molecular mechanisms in the IPFP microenvironment remain unclear. This study investigates the functions of OA-macrophages and their clinical significance.

METHODS

We analyzed single-cell RNA sequencing (scRNA-seq) data from normal and OA patients. Enrichment analysis revealed differences in biological pathways across cell types. Pseudotime and cell-cell communication analyses revealed the developmental trajectory and interactions of OA-macrophages with other cell types. Machine learning (ML) algorithms identified feature genes of OA-macrophages. An OAMGS diagnostic score was developed, and CIBERSORT was used to analyze immune infiltration and its association with immune cells. Rat OA and normal models were established, and feature gene expression was validated using immunofluorescence (IF) staining and quantitative reverse transcription PCR (RT-qPCR).

RESULTS

OA-macrophages play a central role in inflammation and fibrosis, enhancing leukocyte recruitment, chondrocyte apoptosis, and angiogenesis. They interact with chondrocytes, endothelial cells, and fibroblasts via CXCL and NF-κB signaling. High-dimensional weighted gene co-expression network analysis (hdWGCNA) identified 352 module genes linked to OA-macrophages. Machine learning developed a four-gene-based OAMGS score that accurately identifies OA-macrophages, with an AUC of 1 in the discovery cohort and 0.990 in an external cohort. Gene expression was validated in the OA model using RT-qPCR and IF.

CONCLUSION

This study identifies a macrophage subcluster elevated in OA patients. OA-macrophages play an immunoregulatory role and may serve as diagnostic markers. The OAMGS score, based on four genes, provides an accurate diagnostic tool and potential therapeutic target for OA.

Clinical significance of microRNA-328-3p and bone metabolism biomarkers in gout patients with different musculoskeletal ultrasonography imaging

AIMS

MicroRNA (miRNA) participates in the pathophysiological processes of multiple metabolic diseases, including gout. In gout patients, there is concomitant derangement of bone metabolism. The study aimed to explore the correlation of different ultrasonic manifestations and miR-328-3p levels with bone metabolic markers in gout patients.

METHODS

A total of 320 gout patients were grouped according to musculoskeletal ultrasound (MSUS) imaging. Serum osteocalcin (BGP), C-terminal telopeptide of type I collagen (CTX-I) and osteopotin (OPN) levels were detected to evaluate bone metabolism. Serum miR-328-3p levels were detected via qRT-PCR. Pearson's correlation analysis was performed to explore the relationships between the variables.

RESULTS

Patients with tophi accompanied by bone erosion demonstrated significantly elevated levels of BGP and OPN compared to those with tophi or aggregate of MSU crystals in the absence of bone erosions. Cases with long course of disease exhibited more severe bone destruction. Cases without specific clinical manifestations presented the highest levels of serum miR-328-3p, whereas those with bone erosions demonstrated the lowest values. Significantly negative correlations were also detected for serum miR-328-3p levels with BGP and OPN values in all gout patients.

CONCLUSION

Serum miR-328-3p levels were associated with diverse MSUS manifestations in gout patients. MSUS imaging and miR-328-3p levels are capable of reflecting the joint impairment in gout patients.

MiR-103-3p regulates chondrocyte autophagy, apoptosis, and ECM degradation through the PI3K/Akt/mTOR pathway by targeting CPEB3

BACKGROUND

Chondrocyte apoptosis is associated with the severity of cartilage destruction and matrix degeneration in the progression of osteoarthritis. Increasing evidence indicates that autophagy has a significant cytoprotective effect against chondrocyte apoptosis. Here, we investigated the role of microRNA-103-3p (miR-103-3p) in regulating chondrocyte function and elucidated the underlying mechanism.

METHODS

MiR-103-3p expression in interleukin-1β (IL-1β)-stimulated chondrocytes was evaluated using RT-qPCR. The targets of miR-103-3p predicted by online databases were verified using biotin-based pulldown assay and luciferase reporter assay. IL-1β stimulated-chondrocytes were transfected with miR-103-3p inhibitor along with siRNA targeting cytoplasmic polyadenylation element-binding protein3 (siCPEB3), the autophagy inhibitor 3-MA, or the PI3K agonist 740 Y-P. Chondrocyte proliferation was evaluated using cell counting kit-8. Apoptosis was detected by flow cytometry. The levels of apoptosis-, extracellular matrix (ECM)-, autophagy-, and the PI3K/Akt/mTOR pathway-related proteins in chondrocytes were detected using immunoblotting or immunofluorescence.

RESULTS

We found that IL-1β stimulation upregulated miR-103-3p and downregulated CPEB3 in mouse chondrocytes. Inhibiting miR-103-3p reduced IL-1β-induced apoptosis and ECM macromolecule degradation while enhancing autophagy in chondrocytes. MiR-103-3p targeted CPEB3, and its downregulation rescued the expression of level in IL-1β stimulated-chondrocytes. MiR-103-3p downregulation inhibited the PI3K/Akt/mTOR pathway in IL-1β stimulated-chondrocytes by upregulating CPEB3. 3-MA, 740 Y-P, or CPEB3 knockdown counteracted the effect of miR-103-3p downregulation on chondrocyte apoptosis, ECM macromolecule degradation, and autophagy.

CONCLUSION

Overall, inhibition of miR-103-3p reduces IL-1β-induced apoptosis and ECM macromolecule degradation in chondrocytes by enhancing autophagy through the CPEB3/PI3K/Akt/mTOR pathway.

METTL3-mediated m6A modification of circSTAT6 modulates miR-188-3p/Beclin1 axis to promote osteogenic differentiation of mesenchymal stem cells

BACKGROUND

The role of N6-methyladenosine (m6A)-modified circRNAs in disease progression is of great significance. However, the specific impact of m6A modification of circSTAT6 on osteoporosis (OP) is still uncertain.

METHODS

The qRT-PCR was employed to assess the levels of METTL3, circSTAT6, miR-188-3p, and Beclin1. To investigate the interaction between miR-188-3p and circSTAT6 or Beclin, a dual-luciferase reporter assay was performed. To evaluate osteogenic differentiation in bone marrow mesenchymal stem cell (BMSC), western blot analysis was conducted to evaluate the protein expression of osteogenic markers, including ALP, OPN, and Runx2. In addition, alizarin red and alkaline phosphatase (ALP) staining assays were employed to assess osteogenesis.

RESULTS

The findings revealed that the downregulation of circSTAT6 was observed in OP. On the other hand, the overexpression of circSTAT6 was found to enhance the osteogenic differentiation of BMSC. In addition, the involvement of METTL3 in mediating m6A methylation of circSTAT6 was identified, which ultimately promoted osteogenesis. Furthermore, circSTAT6 functioned as an miR-188-3p sponge to regulate the expression of Beclin1. Further study revealed that the osteogenic-enhancing effect caused by circSTAT6 overexpression was counteracted by introducing a miR-188-3p mimic. Similarly, the osteogenic-promoting impact of the miR-188-3p inhibitor was reversed by suppressing Beclin1 expression.

CONCLUSIONS

The present study revealed, for the first time, that METTL3-mediated m6A modification of circSTAT6 regulated the miR-188-3p/Beclin1 axis to promote the osteogenic differentiation of BMSC. These findings offer a potential therapeutic target for the treatment of OP.

Serum miR-519d-3p and BMP2: potential early diagnostic markers and their mechanism in delayed fracture healing

BACKGROUND

Delayed fracture healing (DFH) affects patients' quality of life, and there are limitations in diagnosis by CT scan. The purpose of the study is to evaluate the potential and mechanism of clinical application of miRNAs in DFH for early diagnosis and intervention.

METHODS

Serum samples were obtained from delayed and normal fracture healing patients and the levels of miR-519d-3p and BMP2 were measured by RT-qPCR, and the value of both in the diagnosis of DFH was assessed by ROC curve. Cell viability and apoptosis were monitored using CCK8 kit and flow cytometry, respectively, and mRNA expression of osteogenesis and apoptosis-related genes were detected by RT-qPCR. The molecular interactions were verified using luciferase reporter gene system and RIP technique.

RESULTS

Up-regulation of miR-519d-3p expression and down-regulation of BMP2 in the serum of fracture patients four weeks after surgery can be used as an early warning marker of DFH and a risk factor for poor fracture healing. Further studies showed that overexpression of miR-519d-3p markedly inhibited the expression of RUNX2, OCN and ALP and prevented osteoblast differentiation. Meanwhile, it inhibited cell viability, promoted apoptosis, upregulated Bax and Cleaved-caspase-3 mRNA expression, and downregulated Bcl-2 expression. BMP2, targeted by miR-519d-3p, enhanced osteogenesis and reversed the inhibitory of action miR-519d-3p.

CONCLUSIONS

Serum miR-519d-3p and BMP2 can be used as early diagnostic markers for DFH. miR-519d-3p inhibited osteogenesis by targeting BMP2, which may slow down fracture healing.

MYLK-AS1 improves fracture by targeting miR-146a-5p to regulate cell viability and apoptosis in osteoblasts

BACKGROUND

Delayed fracture healing (DFH) is a significant burden for patients. Therefore, early diagnosis and detection are important for the treatment of DFH. The long non-coding RNA (LncRNA) MYLK-AS1 is abnormally expressed in patients with DFH and has the potential to be used as a diagnostic marker.

METHODS

40 patients with DFH and 87 patients with normal fracture healing were included. The levels of MYLK-AS1, miR-146a-5p and several mRNA markers of osteogenic differentiation were assessed by RT-qPCR. The diagnostic value of MYLK-AS1, miR-146a-5p was assessed using ROC curves. Cell proliferation ability was assessed by CCK-8, and apoptosis rate was detected by flow cytometry. DLR, RIP and RNA pull down assays demonstrated the targeting relationship between MYLK-AS1 and miR-146a-5p.

RESULTS

MYLK-AS1 levels were significantly lower and miR-146a-5p levels were significantly up-regulated in DFH compared to normal healing patients. MYLK-AS1 was found to target miR-146a-5p, and the levels were negatively correlated with each other. MYLK-AS1 with miR-146a-5p is of high value for the diagnosis of DFH. High expression of MYLK-AS1 could inhibit miR-146a-5p levels, support cell proliferation, reduce apoptosis, and increase the levels of osteogenesis-specific matrix proteins and osteogenesis-related regulatory factors.

CONCLUSION

MYLK-AS1 has potential as a diagnostic marker for DFH. By increasing the expression level of MYLK-AS1 in cells can reduce the level of miR-146a-5p, increase the activity of osteoblasts and reduce their apoptosis rate, thus affecting the process of fracture healing.

miR-374-5p inhibits osteogenesis by targeting PTEN/PI3K/AKT signaling pathway

PURPOSE

This study aims to evaluate the effects of miR-374-5p on osteogenesis in rat osteoblasts, validate its target on PTEN, and explore its role in the PTEN/PI3K/AKT signaling pathway during osteoblast differentiation.

METHODS

We transfected 293T cells with miR-374-5p mimics and inhibitors, followed by Western blot and qRT-PCR analyses to assess protein and mRNA expression levels. A dual-luciferase assay was performed to confirm direct targeting. Markers of osteoblast function, such as Runx2, OSX, and OCN, were examined in osteoblasts from rats by qRT-PCR and Western blot. Additionally, we developed a lentiviral vector to overexpress miR-374-5p, which successfully infected rat osteoblast progenitors. Bone formation was subsequently assessed using Alizarin Red staining and ALP activity assays. Finally, rescue experiments were conducted to validate the involvement of the miR-374-5p/PTEN/PI3K/AKT signaling pathway.

RESULTS

Our results demonstrate that miR-374-5p significantly downregulates both the protein and mRNA levels of its target gene PTEN, as confirmed by dual luciferase assays. qRT-PCR and Western blot analyses revealed that osteoblastic markers-including Runx2, OSX, and OCN-were markedly reduced in the miR-374-5p mimic group, whereas an opposite trend was observed in the inhibitor group. In vitro, overexpression of miR-374-5p suppressed osteoblast differentiation, as evidenced by decreased calcium nodule formation and reduced ALP activity compared to controls. Furthermore, co-transfection of miR-374-5p mimics with the PI3K/AKT pathway inhibitor LY294002 in osteoblasts led to significantly lower expression of PI3K/AKT pathway-related genes, and notably, the inhibitory effect of miR-374-5p on osteoblast differentiation was reversed by LY294002 treatment.

CONCLUSION

Our findings indicate that miR-374-5p inhibits osteogenesis in rat osteoblasts by targeting PTEN and modulating the PI3K/AKT signaling pathway.

miR-138-5p inhibits healing of femoral fracture osteogenesis in rats by modulating osteoblast differentiation via SIRT1/FOXO1 axis

BACKGROUND

MicroRNAs have a crucial part to play in maintaining bone formation, signaling, and repair. This research explored the involvement miR-138-5p in modulating osteoblast differentiation in femoral fractures model.

METHODS

The role of mir-138-5p in the healing process of femoral fractures in rats was assessed through micro computed tomography (CT) imaging. After that, qPCR was employed to identify the cellular mRNA expression levels of miR-138-5p, SIRT1, and FoxO1 in either the callus or MC3T3-E1. Next, the protein expression level of Runx2, OPN, OCN and ALP was determined by western blot or ELISA. A dual-luciferase reporter gene assay was implemented to examine the target of miR-138-5p. The quantity of mineralized nodules was measured by means of alizarin red staining.

RESULTS

The miR-138-5p inhibitor promotes the mending of femoral fractures. When it is knocked down, the osteogenic differentiation is promoted, which may be caused by the enhanced activity of ALP and the elevation of the expression of Runx2, OPN and OCN. Meanwhile, an increase in the expression of mir-138-5p impairs the biosynthesis of SIRT1 and FoxO1. When SIRT1 and FoxO1 were downregulated with shRNA, the effect caused by the mir-138-5p inhibitor could be reversed.

CONCLUSION

Our studies uncovered that the overexpressed miR-138-5p might have an inhibitory role in femoral fractures healing by inactivating SIRT1/FOXO1 axis.

LINC00968 accelerates osteogenic differentiation of bone marrow mesenchymal stem cells via the miR-17-5p/STAT3 axis

BACKGROUND

BMSCs with robust osteogenic differentiation capacity can participate in the repair of osteoporotic (OP) bone. Long non-coding RNAs (LncRNAs) serve as crucial regulators of osteogenic differentiation. This study aims to investigate the clinical implications of LINC00968 in OP and elucidate its molecular mechanisms.

METHODS

Patients with OP and controls without OP were enrolled. RT-qPCR was utilized the quantify the levels of LINC00968, miR-17-5p, STAT3, and osteogenic differentiation markers. ROC curve was conducted to evaluate the diagnostic significance. Osteogenic differentiation medium (OM) induced hBMSCs. Flow cytometry was used to examine apoptosis. DLR and RIP assay were performed to validate target binding.

RESULTS

LINC00968 was notably decreased in the serum and bone tissue of patients with OP, whereas it was markedly elevated during osteogenic differentiation of hBMSCs. LINC00968 has 78.65% sensitivity and 71.95% specificity in identifying OP patients from controls. Silencing of LINC00968 sharply diminished ALP activity and osteogenic differentiation markers levels while promoting apoptosis in hBMSCs under OM induction. However, this reduction was notably reversed by the administration of a miR-17-5p inhibitor. Molecularly, miR-17-5p directly targets LINC00968 and STAT3.

CONCLUSIONS

Our results indicate that LINC00968 downregulation is a diagnostic biomarker for OP, facilitating osteogenic differentiation and inhibiting apoptosis via miR-17-5p/STAT3 axis, suggesting a new therapeutic target for OP progression.

MiR-147b-3p promotes osteogenesis by targeting NDUFA4 and PI3K/AKT pathway

BACKGROUND

Osteoporosis (OP) is a progressive metabolic bone disease characterized by impaired bone microarchitecture, decreased bone strength, and dysregulated bone remodeling, leading to an increased risk of fractures. Among osteoporotic fractures, osteoporotic vertebral compression fractures (OVCF) are the most common and can significantly impact patients' quality of life. Growing evidence suggests that microRNAs (miRNAs) play a crucial role in bone homeostasis by regulating osteoblast differentiation, bone metabolism, and remodeling processes. Notably, miR-147b-3p has been found to be downregulated in OVCF; however, its specific role in osteogenic regulation remains largely unknown. Therefore, further investigation is warranted to elucidate the function and underlying mechanism of miR-147b-3p in osteogenic differentiation.

METHODS

The GSE93883 and GSE74209 datasets were retrieved from the Gene Expression Omnibus (GEO) database to investigate specific microRNAs involved in the regulation of osteogenesis. Differential expression of miR-147b-3p and NDUFA4 was assessed between healthy controls and patients with osteoporotic vertebral compression fractures (OVCF) using real-time quantitative PCR.To modulate the expression levels of miR-147b-3p in MC3T3-E1 cells, both the miR-147b-3p mimic and inhibitor were utilized. Cell viability was evaluated via the CCK-8 assay to assess the impact of miR-147b-3p on MC3T3-E1 cell proliferation. Real-time PCR and Western blot analysis were conducted to quantify the expression levels of osteogenic markers across different experimental groups. Alizarin red staining (ARS) was employed to examine the effect of miR-147b-3p on the mineralization capacity of MC3T3-E1 cells. In vivo experiments were performed to evaluate the functional role of miR-147b-3p. Bioinformatics databases were used to predict the potential target gene of miR-147b-3p (NDUFA4), and the predictions were validated by a dual luciferase reporter gene assay.To investigate the regulatory role of the miR-147b-3p/NDUFA4 axis in osteogenic differentiation, MC3T3-E1 cells were transfected with the NDUFA4 overexpression plasmid and miR-147b-3p mimic. Western blot analysis was performed to assess the phosphorylation levels of PI3K and AKT, in order to explore whether the miR-147b-3p/NDUFA4 axis regulates osteogenic differentiation through the PI3K/AKT signaling pathway.

RESULTS

Our results indicated a significant downregulation of miR-147b-3p and a concurrent upregulation of NDUFA4 in patients with osteoporotic vertebral compression fractures (OVCF). A luciferase reporter assay confirmed that NDUFA4 is a direct target gene of miR-147b-3p.To examine the functional role of miR-147b-3p, both in vitro and in vivo experiments were conducted.The experimental findings revealed that the miR-147b-3p mimic significantly enhanced cell viability, increased protein expressions of Alkaline Phosphatase (ALP) and Runt-related Transcription Factor 2 (RUNX2), and promoted mineralization as evidenced by Alizarin Red S staining. Conversely, treatment with the miR-147b-3p inhibitor or overexpression plasmid for NDUFA4 (pNDUFA4) produced opposite effects.Furthermore, the miR-147b-3p/NDUFA4 axis was found to regulate the PI3K/AKT signaling pathway.The miR-147b-3p mimic significantly increased the phosphorylation levels of PI3K (p-PI3K) and AKT (p-AKT), whereas pNDUFA4 led to their reduction.

CONCLUSIONS

This study demonstrated that miR-147b-3p plays a crucial role in promoting osteogenic differentiation in osteoporotic vertebral compression fractures (OVCF) by targeting NDUFA4 and modulating the PI3K/AKT signaling pathway. These findings provide new insights into the molecular mechanisms underlying the progression of osteoporotic vertebral fractures.

Mechanism of lncRNA ZFAS1 mediating nucleus pulposus cell pyroptosis in intervertebral disc degeneration

BACKGROUND

This study investigates the mechanism of lncRNA ZFAS1 in pyroptosis of TNF-α-induced nucleus pulposus cells (NPCs) in intervertebral disc degeneration (IDD).

METHODS

Mouse NPCs were isolated and induced by TNF-α to establish a cell model of IDD. The cell viability was evaluated by MTT assay. NLRP3, GSDMD-N, and cleaved-Caspase1 expressions were detected by Western blot. IL-1β and IL-18 contents were detected by ELISA. RT-qPCR was performed to determine ZFAS1, miR-155-3p, and METTL14 expressions. After intervening in ZFAS1 expression, the effect of ZFAS1 on pyroptosis was verified by Western blot and ELISA assays. RNA pull down or dual luciferase assay verified the binding between ZFAS1, miR-155-3p, and METTL14.

RESULTS

TNF-α induced pyroptosis of NPCs and promoted ZFAS1 expression. Silence of ZFAS1 repressed pyroptosis of TNF-α-induced NPCs. Mechanistically, ZFAS1 upregulated the transcription of METTL14 by competitively binding to miR-155-3p, thus enhancing NLRP3/Caspase-1-mediated NPC pyroptosis. Inhibition of miR-155-3p or overexpression of METTL14 alleviated the inhibitory effect of ZFAS1 silencing on TNF-α-treated NPC pyroptosis.

CONCLUSION

ZFAS1 facilitates NLRP3/Caspase-1-mediated pyroptosis of NPCs in IDD via miR-155-3p/METTL14 axis.

Involvement of icaritin in the regulation of osteocyte exosomal microRNAs

OBJECTIVE

To explore the effects of Icaritin (ICA) on the regulation of osteocyte exosomal miRNAs and to promote the understanding of the potential molecular mechanisms involved in bone repair by ICA.

METHODS

MLO-Y4 cells were treat with PBS or 10 µM ICA for 24 h and the supernatant was collected. Exosomes were isolated and purified according to standard methods, and identified by transmission electron microscopy, nanoparticle tracking analysis and protein blotting. Exosomal miRNAs were analysed by RNA sequencing.

RESULTS

Osteocyte exosomes were successfully isolated and characterised. MiRNA sequencing showed that two known exosomal miRNAs (miR-128-3p, miR-30a-5p) were significantly up-regulated and two were significantly down-regulated (miR-5112, miR-1285) after ICA intervention.

CONCLUSION

Based on the findings, ICA regulates several miRNAs of osteocytes, which deepen our understanding of the therapeutic effects and mechanisms of ICA on skeletal diseases.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Osteocytes are the most abundant cell type in bone tissue, of which the impact on bone homeostasis is still not clear. This study explored the impact of icaritin on osteocytes and their derived exosomes. By doing so, we hope to contribute to the understanding the therapeutic potential of ICA and osteocytes in maintaining bone health and treating conditions such as osteoporosis.

New Insights on the miRNA Role in Diabetic Tendinopathy: Adipose-Derived Mesenchymal Stem Cell Conditioned Medium as a Potential Innovative Epigenetic-Based Therapy for Tendon Healing

BACKGROUND

Adipose-derived mesenchymal stem cell conditioned medium (ASC-CM) improved the viability and wound closure of human tenocytes (HTCN) exposed to high glucose (HG) by activating the transforming growth factor beta 1 (TGF-β1) pathway.

OBJECTIVES

Since ASC-CM can also modulate microRNAs (miRNAs) in recipient cells, this study investigated the effects of ASC-CM on the miRNAs regulating tendon repair (miR-29a-3p, miR-210-3p and miR-21-5p) in HG-HTNC.

METHODS

ASC-CM was obtained by ASCs isolated from the abdominal fat tissue of seven non-diabetic patients. HTNC were cultured in HG for 20 days, then scratched and exposed for 24 h to ASC-CM. qRT-PCR and ELISAs assessed miRNA and target levels.

RESULTS

HG-HTNC exhibited a significant downregulation of miRNAs. ASC-CM restored the levels of miRNAs and their related targets involved in tendon repair.

CONCLUSIONS

The epigenetic modulation observed in HG-HTNC exposed to ASC-CM could be an innovative option in the management of diabetic tendinopathy.

miRNAs and their multifaceted role in cutaneous wound healing

The dynamic, complex process of cutaneous wound healing is required to restore skin integrity following an injury. This intricate process consists of four sequential and overlapping phases: hemostasis, inflammation, proliferation, and remodeling. Hemostasis immediately begins to function in response to vascular injury, forming a clot that stops the bleeding. To fight infection and remove debris, immune cells are enlisted during the inflammatory phase. Angiogenesis, re-epithelialization, and the creation of new tissue are all components of proliferation, whereas tissue maturation and scarring are the outcomes of remodeling. Chronic wounds, like those found in diabetic ulcers, frequently stay in a state of chronic inflammation because they are unable to go through these stages in a coordinated manner. The important regulatory roles that microRNAs (miRNAs) play in both normal and pathological wound healing have been highlighted by recent investigations. The miRNAs, small non-coding RNAs, modulate gene expression post-transcriptionally, profoundly impacting cellular functions. During the inflammatory phase, miRNAs control pro- and anti-inflammatory cytokines, as well as the activity of immune cells such as neutrophils and macrophages. Additionally, miRNAs are essential components of signaling networks related to inflammation, such as the toll-like receptor (TLR), nuclear factor kappa B (NF-kB), and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways. Some miRNAs have been discovered to either increase or alleviate inflammatory reactions, indicating their potential as therapeutic targets. Other miRNAs aid in angiogenesis by promoting the development of new blood vessels, which are essential for providing oxygen and nutrients to the healing tissue. They also affect keratinocyte migration and proliferation during the re-epithelialization phase, which involves growing new epithelial cells over the lesion. Another function of miRNAs is that they control the deposition of extracellular matrix (ECM) and the creation of scars during the remodeling phase. The abnormal expression of miRNAs in chronic wounds has led to the exploration of miRNA-based treatments. With a focus on resistant instances such as diabetic wounds, these therapeutic techniques seek to improve wound healing results by correcting the dysregulated miRNA expression.

Unveiling new therapeutic horizons in rheumatoid arthritis: an In-depth exploration of circular RNAs derived from plasma exosomes

Rheumatoid arthritis (RA), a chronic inflammatory joint disease causing permanent disability, involves exosomes, nanosized mammalian extracellular particles. Circular RNA (circRNA) serves as a biomarker in RA blood samples. This research screened differentially expressed circRNAs in RA patient plasma exosomes for novel diagnostic biomarkers. In this study, samples of RA patients with insufficient response to methotrexate (MTX-IR), combined use of tumor necrosis factor inhibitors (TNFi) were followed up for half a year, and 56 circRNA samples of self-test data were stratified into training, testing, and external validation cohorts according to whether American College of Rheumatology 20% improvement criteria (ACR20) was achieved. A diagnostic xgboost model was developed using common hub genes identified by random forest and least absolute shrinkage and selection operator (LASSO), with intersection genes derived from overlapping machine learning-selected genes. Diagnostic performance evaluated via receiver operating characteristic (ROC) curves using pROC for area under the curve (AUC). Optimal LASSO model with 4 circRNAs determined, with AUC > 0.6 for key genes. The model validation performed well on the test set, but not significantly on the validation set. Then, circRNA screening was performed in combination with clinical data, and cross-validation identified hsa-circ0002715, hsa-circ0001946, hsa-circ0000836, and rheumatoid factor (RF) as key genes, among which hsa-circ0002715 and hsa-circ0001946 were emphasized as key markers on the training set. In addition, the morphology and size of exosomes and the expression of CD9 and CD81 verified the successful extraction of exosomes. The qPCR analysis of plasma exosomes in TNFi patients found that the expression of hsa-circ0002715 was higher than that in patients who didn't reach ACR20, and the expression of hsa-circ0001946 was lower than that in patients who didn't reach ACR20. The above studies suggested that hsa-circ0002715 and hsa-circ0001946 may become markers for predicting MTX-IR RA patients and TNFi precision treatment.

miR-208a-3p discriminates osteoporosis, predicts fracture, and regulates osteoclast activation through targeting STC1

BACKGROUND

Osteoporosis (OP) frequently occurs in post-menopausal women, increasing the risk of fracture. Early screening OP could improve the prevention of fractures.This study focused on the significance of miR-208a-3p in diagnosing OP and development regulation, aiming to explore a novel biomarker and therapeutic target for OP.

METHODS

The study enrolled a total of 154 post-menopausal women and grouping was performed based on the incidence of OP and fracture. The significance of miR-208a-3p was evaluated from the perspectives of menopausal correlation, OP diagnosis, and fracture prediction. In mechanism, the regulatory effect and mechanism of miR-208a-3p on osteoclast activation was investigated.

RESULTS

miR-208a-3p was menopause-related showing a negative correlation with E2 and positive correlations with FSH and LH. Significant upregulation of miR-208a-3p was observed in post-menopausal women with OP and showed significant diagnostic potential. Increasing miR-208a-3p was positively correlated with bone metabolism markers and negatively correlated with BMD of post-menopausal women with OP. Moreover, miR-208a-3p was also identified as a risk factor for fracture. STC1 was identified as a direct target of miR-208a-3p and was negatively regulated by miR-208a-3p. Silencing miR-208a-3p significantly alleviated macrophage inflammation and osteoblast activation, which was reversed by the knockdown of STC1.

CONCLUSION

Serum miR-208a-3p served as a diagnostic biomarker for OP and a risk factor for fracture in post-menopausal women. miR-208a-3p regulated macrophage inflammation and further mediated osteoclast activation via targeting STC1.

Autophagy activation alleviates annulus fibrosus degeneration via the miR-2355-5p/mTOR pathway

BACKGROUND

Intervertebral disc degeneration disease (IVDD) is a major cause of disability and reduced work productivity worldwide. Annulus fibrosus degeneration is a key contributor to IVDD, yet its mechanisms remain poorly understood. Autophagy, a vital process for cellular homeostasis, involves the lysosomal degradation of cytoplasmic proteins and organelles. This study aimed to investigate the role of autophagy in IVDD using a hydrogen peroxide (H2O2)-induced model of rat annulus fibrosus cells (AFCs).

METHODS

AFCs were exposed to H2O2 to model oxidative stress-induced degeneration. Protein expression levels of collagen I, collagen II, MMP3, and MMP13 were quantified. GEO database analysis identified alterations in miR-2355-5p expression, and its regulatory role on the mTOR pathway and autophagy was assessed. Statistical tests were used to evaluate changes in protein expression and pathway activation.

RESULTS

H2O2 exposure reduced collagen I and collagen II expression to approximately 50% of baseline levels, while MMP3 and MMP13 expression increased twofold. Activation of autophagy restored collagen I and II expression and decreased MMP3 and MMP13 levels. GEO analysis revealed significant alterations in miR-2355-5p expression, confirming its role in regulating the mTOR pathway and autophagy.

CONCLUSIONS

Autophagy, mediated by the miR-2355-5p/mTOR pathway, plays a protective role in AFCs degeneration. These findings suggest a potential therapeutic target for mitigating IVDD progression.

LINC00941 affects the proliferation, apoptosis and differentiation of osteoblasts by regulating the miR-335-5p/KAT7 axis

BACKGROUND

Fractures are the prevalent traumatic conditions encountered in orthopedic practices. The rising incidence of fractures has emerged as a pressing global health concern. Although the majority of individuals with fractures experience complete recovery of bone structure and function, approximately 10% of those with fractures exhibit delayed fracture healing (DFH). The objective of this investigation was to explore the function and underlying mechanisms of LINC00941 in the advancement of DFH, as well as its involvement in the regulation of osteoblastic differentiation by regulating the miR-335-5p/KAT7 axis.

METHODS

The expression levels of LINC00941, miR-335-5p, KAT7 and osteoblast differentiation-related markers were assessed using RT-qPCR. The proliferation of MC3T3-E1 cells was evaluated through the CCK-8 assay, and cell apoptosis was analyzed via flow cytometry. The targeted regulatory relationships between LINC00941 and miR-335-5p, as well as between miR-335-5p and KAT7 were verified by a dual-luciferase reporter gene assay.

RESULT

The expression of LINC00941 was significantly up regulated, while miR-335-5p exhibited a notable downregulation in DFH patients, both of LINC00941 and miR-335-5p have been identified as potential predicted markers for DFH. Furthermore, LINC00941 has been demonstrated to inhibit osteoblast proliferation, promote apoptosis, and suppress osteoblast differentiation through the regulation of the miR-335-5p/KAT7 axis.

CONCLUSION

LINC00941/ miR-335-5p/KAT7 axis may be a therapeutic target for DFH.

LINC01271 promotes fracture healing via regulating miR-19a-3p/PIK3CA axis

OBJECTIVE

Osteoporosis increases the risk of fragility fractures, impacting patients' lives. This study aimed to investigate whether LINC01271 was involved in the process of fragility fractures and healing, providing a new perspective for its diagnosis and treatment.

METHODS

This study included 94 healthy individuals, 82 patients with osteoporosis, and 85 patients with fragility fractures as subjects. RT-qPCR was used to measure the levels of LINC01271, miR-19a-3p, PIK3CA, and osteogenic differentiation markers in osteoblasts and subjects' serum. Luciferase reporter assays, RIP experiments, and RNA pull-down assays were utilized to verify the target relationships between LINC01271 and miR-19a-3p, as well as between miR-19a-3p and PIK3CA. Cell proliferation and apoptosis were assessed using CCK-8 assays and flow cytometry.

RESULTS

Compared to the healthy control group, the serum levels of LINC01271 were significantly reduced in patients with osteoporosis and fragility fractures. Furthermore, LINC01271 levels increased with time-dependent fracture healing. In vitro studies indicated that LINC01271 boosted osteoblast proliferation, inhibited apoptosis, and augmented osteogenic differences, whereas its inhibition reverses their effects. LINC01271 and PIK3CA were identified as targets of miR-19a-3p, and overexpression of miR-19a-3p could antagonize the effect of LINC01271 in promoting fracture healing.

CONCLUSION

The results indicated that LINC01271 may play a key role in osteoblast function and fracture healing through its interaction with miR-19a-3p and regulation of PIK3CA.

circ_0075048 silencing regulates LCP1 to improve IL-1β-induced chondrocyte injury by binding with miR-663b

BACKGROUND

Osteoarthritis (OA) is a common type of degenerative arthropathy. Previous studies have demonstrated that circular RNAs (circRNAs) are involved in the progression of OA. This study aimed to investigate the role and associated mechanism of circ_0075048 in OA.

METHODS

The expression of circ_0075048 was analyzed based on the Gene Expression Omnibus dataset GSE178724. Human chondrocytes were stimulated with IL-1β to establish an in vitro OA model. Bioinformatic analysis was performed to identify target genes of circ_0075048. The expression of circ_0075048, miR-663b, and LCP1 was detected by quantitative reverse transcription-polymerase chain reaction. The cell viability and apoptosis of C28/I2 cells were determined using Cell Counting Kit-8 assay and flow cytometry. Protein expression was detected using western blotting.

RESULTS

The expression of circ_0075048 was up-regulated in IL-1β-induced chondrocytes. circ_0075048 silencing promoted the viability of and inhibited the apoptosis of and extracellular matrix (ECM) production of chondrocytes. circ_0075048 was found to be a sponge of miR-663b and LCP1 was found to be a target of miR-663b. circ_0075048 silencing increased miR-663b expression but decreased LCP1 expression levels in chondrocytes. An miR-663b inhibitor eliminated the protective effect of a circ_0075048 small interfering RNA (siRNA) on chondrocytes. However, an LCP1 siRNA abolished the effect of the miR-663b inhibitor on chondrocytes.

CONCLUSION

circ_0075048 silencing inhibited the apoptosis of and ECM degradation in IL-1β-induced chondrocytes by regulating miR-663b/LCP1 axis.

miR-468-3p suppresses osteogenic differentiation of BMSCs by targeting Runx2 and inhibits bone formation

An improved understanding of the molecular actions underpinning bone marrow mesenchymal stem cell (BMSC) differentiation could highlight new therapeutics for osteoporosis (OP). Current evidence indicates that microRNAs (miRNAs) exert critical roles in many biological systems, including osteoblast differentiation. In this study, we examined miR-468-3p effects on osteogenic differentiation (OD). Distinct miR-468-3p reductions were identified during OD. MiR-468-3p also suppressed BMSC OD in gain- and loss-of-function assays, while it negatively regulated Runx2 as shown by molecular, protein, and bioinformatics approaches. When Runx2 was inhibited by small-interfering RNA (siRNA), the inhibitory effects of miR-468-3p toward BMSC osteogenesis were considerably reversed. Also, silenced miR-468-3p in ovariectomized (OVX) and sham mice augmented bone mass (BM) and bone formation (BF) and improved trabecular (Tb) microarchitecture. Therefore, miR-468-3p is a novel Runx2 regulator with key physiological action in BF and OD.

CRNDE alleviates IL-1β-induced chondrocyte damage by modulating miR-31/NF-κB pathway

BACKGROUND

The long non-coding RNA CRNDE (CRNDE) has been identified as a lncRNA associated with osteoarthritis (OA), playing a role the age-related degeneration of articular cartilage. However, the precise mechanism by which CRNDE affects the physiological functions of OA chondrocytes remains unclear.

METHODS

To simulate the inflammatory conditions observed in OA, interleukin (IL)-1β-stimulated chondrocyte C-28/I2 cells were utilized. The expression levels of CRNDE and miR-31 were assessed using reverse transcription-polymerase chain reaction (RT-PCR). Chondrocyte viability and apoptosis were evaluated through CCK-8 assay and flow cytometry, respectively. The levels of IL-6, IL-1β and Tumor necrosis factor (TNF-α) were determined using enzyme-linked immunosorbent assay (ELISA). mRNA expression levels of MMP-13, Aggrecan and COL2A1 were detected by quantitative RT-PCR. Western blot analysis was performed to evaluate the protein levels of factors related to cartilage matrix degradation, including p-p65, p65 and p-IκBα of the NF-κB pathway.

RESULTS

CRNDE expression was downregulated in both OA cartilage tissues and IL-1β-stimulated chondrocytes. Overexpression of CRNDE mitigated IL-1β-stimulated chondrocytes apoptosis, inflammatory responses, and cartilage matrix degradation. Compared with healthy controls, OA tissues exhibited reduced expression of miR-31, which was negatively correlated with the expression of CRNDE. Additionally, overexpression of miR-31 partially reversed the inhibitory effects of CRNDE on apoptosis, inflammation, cartilage matrix degradation, and the inactivation of Nuclear factor (NF)-κB pathway induced by IL-1β stimulation. Moreover, silencing of CRNDE exacerbated IL-1β-induced chondrocytes damage, which was aliviated by the NF-κB pathway inhibitor, Bay 11-7082.

CONCLUSION

CRNDE alleviated IL-1β-induced injuries in OA chondrocytes by suppressing the miR-31-mediated NF-κB signaling pathway.

WTAP mediates IL-1β-induced chondrocyte injury by enhancing CA12 mRNA stability depending on m6A modification

BACKGROUND

Osteoarthritis (OA) poses a significant risk to the mobility of patients. Carbonic anhydrase 12 (CA12) can boost apoptosis and inflammation in several cancers, but its role in OA is unknown.

METHODS

Differentially expressed genes in OA were analyzed using the GEO database (GSE169077). RT-qPCR and western blot estimated relative mRNA and protein levels of CA12. Cell viability and apoptosis were estimated by cell counting and flow cytometry assays. Oxidative stress (OxS) was determined by detecting with ROS and MDA levels, as well as CAT and SOD activities. Cytokine levels of IL-6 and TNF-α were detected by ELISA. Parameters associated with apoptosis and extracellular matrix (ECM) were detected by western blot. The m6A modification profile was determined by methylated RNA immunoprecipitation assays.

RESULTS

Relative CA12 and wilms' tumor 1-associating protein (WTAP) mRNA and protein levels were overexpressed in OA articular cartilages and IL-1β-challenged chondrocytes CHON-001. CA12 silencing impaired IL-1β-induced cell apoptosis, inflammation, OxS, and ECM degradation in chondrocytes. Yet, CA12 overexpression exerted an opposing function. WTAP reinforced the stability of CA12 mRNA depending on the m6A modification. Furthermore, WTAP knockdown weakened cell apoptosis, inflammation, OxS, and ECM degradation in chondrocytes induced by IL-1β, but these changes were impaired after CA12 overexpression. In addition, WTAP knockdown mitigates cartilage degeneration in DMM-induced mouse models.

CONCLUSION

IL-1β-induced WTAP enhances CA12 mRNA stability depending on m6A modification, thus promoting chondrocyte apoptosis, inflammatory response, OxS, and ECM degradation, providing evidence to support the possibility of WTAP and CA12 as potential targets for OA treatment.

Hsa_circ_0072732 enhances sunitinib resistance of renal cell carcinoma by inhibiting ferroptosis

BACKGROUND

Renal cell carcinoma (RCC) is one of the most diagnosed urological malignancies with high mortality and increasing incidence. What's more, the sunitinib resistance undoubtedly increased the difficulties in RCC therapy. Circular RNAs (circRNAs) are a newly found type of non-coding RNAs with a special circular structure, and are found to participate in the occurrence development, chemoresistance, and prognosis of cancers. Ferroptosis regulates disease progression mainly via polyunsaturated fatty acid metabolism and glutamine catabolic pathways. The mechanism of circRNAs contributed to sunitinib resistance through ferroptosis has not been elucidated clearly.

MATERIALS AND METHODS

In our research, we identified a novel circRNA Hsa_circ_0072732 from circRNA datasets (GSE108735 and GSE100186). RNase R and Actinomycin D assays were used to detect the loop structure and stability of circRNAs. qRT-PCR and western blot were used for the detection of RNA and protein levels. CCK8 assays were used to detect proliferation and cell viability. Lipid peroxidation (MDA), and reactive oxygen species (ROS) were detected by indicted kits. Dual-luciferase reporter and RNA pull-down assays were used to detect the RNA interactions.

RESULTS

Our results showed that Hsa_circ_0072732 was highly expressed in RCC cells. Further investigations showed that the silence of Hsa_circ_0072732 could increase RCC sensitivity to sunitinib. Hsa_circ_0072732 contributed to sunitinib chemoresistance by impairing ferroptosis. Hsa_circ_0072732 exerts its function mainly by acting as sponges for miR-548b-3p and regulating the expression SLC7A11. Our research suggests that ferroptosis is involved in sunitinib resistance, and targeting ferroptosis is a promising way for RCC treatment.

CONCLUSION

Our research suggests Hsa_circ_0072732 enhanced renal cell carcinoma sunitinib resistance by inhibiting ferroptosis through miR-548b-3p/SLC7A11.

Functional mechanism and clinical implications of mir-1271-5p in pilon fracture healing processes

BACKGROUND

Pilon fractures are challenging to treat and carry a risk of delayed healing. MicroRNA (miRNA) is closely associated with various diseases due to its ability to regulate gene expression. Consequently, this study aimed to examine the connection between miR-1271-5p expression levels and pilon fracture healing processes, while also exploring the underlying mechanisms. The objective of this research was to provide valuable insights for the future clinical treatment of pilon fractures.

MATERIALS

Venous blood samples were obtained for RNA extraction from patients with normal healing (n = 107) or delayed healing (n = 45) of pilon fractures. The expression levels of miR-1271-5p were measured using qRT-PCR. MiR-1271-5p and ZBTB7A biological functions in MC3T3-E1 cells were examined using the Cell Counting Kit-8 (CCK-8), flow cytometry, and qRT-PCR. Finally, an investigation into the underlying mechanisms was carried out using a dual luciferase reporter assay.

RESULTS

This study found that, compared to those who healed normally, patients who experienced delayed healing of pilon fractures had significantly higher expression of miR-1271-5p. This suggests that miR-1271-5p may be an indicator for delayed healing in pilon fractures. Moreover, the upregulation of miR-1271-5p may result in a reduction of ZBTB7A expression, which is thought to mediate the effects of miR-1271-5p on MC3T3-E1 cell activities.

CONCLUSIONS

MiR-1271-5p was involved in the healing processes of pilon fractures via targeting ZBTB7A. MiR-1271-5p was a possible target for the therapy of pilon fractures.

lncRNA CASC11 regulates the progress of delayed fracture healing via sponging miR-150-3p

BACKGROUND

Long non-coding RNA (lncRNA) plays a pivotal role in bone regeneration by interaction with microRNAs (miRNAs) and constructing a lncRNA-miRNA regulatory network.

OBJECTIVES

This research aimed to elucidate the role of lncRNA CASC11 in the delayed healing process of tibial fractures and to explore its potential regulatory mechanisms.

MATERIALS AND METHODS

The expression levels of CASC11 and miR-150-3p in serum samples were detected and the predictive capability of CASC11 regarding delayed healing in fracture patients. Furthermore, the study confirmed the accuracy of the binding sites between CASC11 and miR-150-3p. Subsequently, overexpression/interference plasmids of CASC11, along with overexpression plasmids co-transfected with both CASC11 and miR-150-3p, were systematically introduced into MC3T3-E1 cells to investigate their effects on the expression of osteogenic marker genes, as well as their influence on cellular proliferation and apoptosis.

RESULTS

The expression levels of CASC11 were significantly elevated, while miR-150-3p levels were markedly decreased in individuals exhibiting delayed fracture healing (P < 0.001). CASC11 was observed to suppress the expression of osteogenic marker genes, inhibit the proliferation of MC3T3-E1 cells, and promote cell apoptosis (P < 0.05). Furthermore, the overexpression of miR-150-3p effectively countered the inhibitory impact of CASC11 on osteogenic differentiation and the promoting effect on cell apoptosis (P < 0.05).

CONCLUSION

The sponging effect of CASC11 on miR-150-3p led to delayed fracture healing. CASC11 emerges as a potential target for treating delayed fracture healing.

MiR203a-3p as a potential biomarker for synovial pathology associated with osteoarthritis: a pilot study

BACKGROUND

Osteoarthritis (OA) is a degenerative musculoskeletal disease that significantly impacts the quality of life. Currently, no validated biomarkers for early detection of OA are defined. The possibility of discovering OA biomarkers is the focus of this study.

METHODS

Human primary OA synovial cells (SVs), isolated from discarded joint tissue of patients with Kellgren & Lawrence score (KL) < 3, (mild/moderate) and KL ≥ 3 (severe), were characterized by FACS analysis. Through qRT-PCR and ELISA assays the inflammation, fibrosis status and the different miRNAs expression has been investigated. The role of miR-203a-3p and its precursors were evaluated through gain and loss of function study, IL-1β synoviocytes treatments and methylation analysis of miR203a promoter. The qRT-PCR analysis of miR203a-3p and pre-miR203a on plasma (isolated 24 h before surgery, 3 days and 1 month after surgery) and synovial fluid (recovered during the surgery) were done to support our in vitro data.

RESULTS

MiR203a-3p expression is inversely correlated with the aggressiveness of OA, modulating the expression of epithelial to mesenchymal transition (EMT) and pro-inflammatory factors, as well as regulating the expression of secreted protein acidic and rich in cysteine (SPARC) mRNA. Methylation analysis of the miR203a promoter and SVs IL-1β treatment's highlighted the impact of inflammation on miR203a-3p and pre-miR203a expression; as confirmed by both miRNAs detection in biological fluids derived from patients with severe OA.

CONCLUSION

Our preliminary results suggest that miR-203a-3p might be a potential candidate for staging OA progression and a new protective/predictive biomarker for synovial OA degeneration. Further studies are needed to validate its potential impact on OA.

CRISPR activation identifies a novel miR-2861 binding site that facilitates the osteogenesis of human mesenchymal stem cells

We investigated the regulation of histone deacetylases (HDACs) by miR-2861 in the osteoblastic differentiation of human mesenchymal stem cells (MSCs) and miR-2861 binding site by CRISPR activation (CRISPRa). Transfection of miR-2861 into human MSCs was performed and the effect on osteoblast differentiation was analyzed. Using catalytically inactive Cas12a, the CRISPRa system induced targeted overexpression of endogenous miRNA and repressed the luciferase activities of reporters that contained functional miRNA target sites. The delivery of miR-2861 into MSCs enhanced osteoblast differentiation by decreased expressions of the HDAC1, 4 and 5 genes. The mechanism of HDAC5 repression by miR-2861 in humans has not been fully elucidated. To this end, the HDAC5 mRNA sequence was analyzed and a putative primate-specific miR-2861 binding site was identified in the 3' untranslated region (3'-UTR). CRISPRa was applied to validate the putative binding site and an increase in endogenous miR-2861 was found to repress the expression of a reporter that contained the novel miR-2861 binding site. The delivery of miR-2861 to human MSCs enhanced osteoblast differentiation. In the 3'-UTR, the HDAC5 repression was mediated by the miR-2861 binding site, and miR-2861 promoted osteoblast differentiation via the inhibition of HDAC5 through a primate-specific miRNA binding site. Therefore, miRNAmiR-2861 with the CRISPRa methods might be a good biomaterial for osteogenesis augmentation.

METTL3 accelerates staphylococcal protein A (SpA)-induced osteomyelitis progression by regulating m6A methylation-modified miR-320a

Osteomyelitis (OM) is an inflammatory disease of bone infection and destruction characterized by dysregulation of bone homeostasis. Staphylococcus aureus (SA) has been reported to be the most common pathogen causing infectious OM. Recent studies have demonstrated that N6-methyladenosine (m6A) regulators are associated with the development of OM. However, the molecular mechanism of m6A modifications in OM remains unclear. Here, we investigated the function of methyltransferase-like 3 (METTL3)-mediated m6A modification in OM development. In this study, human bone mesenchymal stem cells (hBMSCs) were treated with staphylococcal protein A (SpA), a vital virulence factor of SA, to construct cell models of OM. Firstly, we found that METTL3 was upregulated in OM patients and SpA-induced hBMSCs, and SpA treatment suppressed osteogenic differentiation and induced oxidative stress and inflammatory injury in hBMSCs. Functional experiments showed that METTL3 knockdown alleviated the inhibition of osteogenic differentiation and the promotion of oxidative stress and inflammation in SpA-treated hBMSCs. Furthermore, METTL3-mediated m6A modification upregulated miR-320a expression by promoting pri-miR-320a maturation, and the mitigating effects of METTL3 knockdown on SpA-mediated osteogenic differentiation, oxidative stress and inflammatory responses can be reversed by miR-320 mimic. In addition, we demonstrated that phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) was a downstream target of miR-320a, upregulation of PIK3CA alleviated miR-320a-induced inhibition of osteogenic differentiation, and upregulation of oxidative stress and inflammatory responses during SpA infection. Finally, we found that silencing METTL3 alleviated OM development by regulating the miR-320a/PIK3CA axis. Taken together, our data demonstrated that the METTL3/m6A/miR-320a/PIK3CA axis regulated SpA-mediated osteogenic differentiation, oxidative stress, and inflammatory responses in OM, which may provide a new therapeutic strategy for OM patients.

The role of lncRNA TSIX in osteoarthritis pathogenesis: mechanistic insights and clinical biomarker potential

BACKGROUND

This study seeks to elucidate the expressions of lncRNA TSIX in Osteoarthritis (OA) and to explore its mechanisms in regulating OA progression.

METHODS

RT-qPCR was employed to analyze the expression of TSIX in OA patients classified by Kellgren-Lawrence (K-L) grades. Receiver operator characteristic (ROC) was conducted to evaluate the diagnostic value of TSIX. Correlation between TSIX levels and clinical scores such as Lysholm and visual analogue scale (VAS) score was evaluated using Pearson method. IL-1β-induced SW1353 cells served as an in vitro model. The cell function were assessed by flow cytometry and cell counting kit-8 (CCK-8) assay. The relationship between TSIX and miR-320a was verified by luciferase reporting system, while bioinformatics approaches were utilized to predict the downstream target genes of miR-320a.

RESULTS

The findings revealed that TSIX level in OA patients was elevated compared to that of the control group, with a notable progressive increase in TSIX expression correlated with higher K-L grades. In OA patients, the Lysholm score showed a negative correlation with TSIX expression, while the VAS score displayed a positive correlation with TSIX levels. Cell studies demonstrated that inhibition of TSIX enhanced cell viability and mitigated IL-1β-induced apoptosis by targeting miR-320a, in addition to promoting Aggrecan and Collagen II secretion. Luciferase reporter assay further validated the targeting interaction among TSIX, miR-320a, and PTEN.

CONCLUSIONS

This study demonstrated an increased expression of TSIX in OA patients. It suggests that TSIX may play a role in chondrocyte dysfunction during OA by modulating the miR-320a/PTEN axis.

Role of mir-32-3p in the diagnosis and risk assessment of osteoporotic fractures

BACKGROUND

Osteoporotic fractures (OPF) are fractures that occur with low-energy injuries or during daily activities, representing a serious consequence of osteoporosis (OP). With the worsening of population aging, the number of OPF patients continues to expand, causing a significant burden on families and society. Consequently, it is significant to diagnose and analyze OPF at the molecular level.

OBJECTIVE

The aim of this research was to explore the diagnostic value of miR-32-3p in OPF patients and to exploit new biomarkers for clinical applications.

METHODS

The miR-32-3p expression level of patients was detected by RT-qPCR. Diagnostic accuracy of miR-32-3p analyzed adopting ROC curve. Additionally, the risk factors correlation with the occurrence of OPF were assessed by logistic analysis. The effect of miR-32-3p on BMSCs was verified by in vitro transfection experiments.

RESULTS

miR-32-3p expression was lower in OPF patients than in OP patients. ROC curve implied that miR-32-3p exhibits commendable sensitivity (88.9%) and specificity (75.6%) to differentiate between OP and OPF patients (AUC = 0.905, P < 0.001). Furthermore, miR-32-3p was correlated with the development of OPF and was a risk factor for OPF (P < 0.001). Functional assays revealed that transfection with miR-32-3p mimic could promote proliferation and inhibit apoptosis, whereas transfection with miR-32-3p inhibitor had the opposite effect.

CONCLUSION

miR-32-3p demonstrates significant diagnostic potential for OPF patients. It is likely that miR-32-3p probably is a new diagnosis biomarker for OPF, offering promising therapeutic avenues through targeted interventions.

Identification of circRNA CDR1as/miR-214-3p regulatory axis in Legg-Calvé-Perthes disease

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) commonly occurs among adolescents, threatening their health. However, the potential mechanism underlying LCPD remains unclear. miR-214-3p is shown as a critical role in LCPD development with unspecified upstream regulators.

METHODS

Levels of miR-214-3p and circCDR1as in healthy controls and LCPD patients were determined by qRT-PCR. The role of circCDR1as/miR-214-3p axis in LCPD was determined by testing the cell viability and apoptosis in TC28 cells and primary chondrocytes. Regulation between circCDR1as and miR-214-3p was examined by RIP and ChIP assays. The inflammatory response and angiogenesis were evaluated by M2 macrophage polarization and HUVECs tumor formation.

RESULTS

circCDR1as was overexpressed in LCPD patients with a negative correlation with miR-214-3p. Inhibition of circCDR1as alleviated the cell viability and apoptosis of DEX-treated chondrocytes, stimulated M2 macrophage polarization and angiogenesis. miR-214-3p was proved as a downstream effector to participate in circCDR1as mediated actions. circCDR1as recruited PRC2 complex to epigenetically suppress miR-214-3p.

CONCLUSION

Our study illustrated the role and mechanism of circCDR1as in LCPD development by targeting miR-214-3p, highlighting its potential in the therapy for LCPD.

Low shear stress protects chondrocytes from IL-1β-induced apoptosis by activating ERK5/KLF4 signaling and negatively regulating miR-143-3p

OBJECTIVE

This study investigated the protective effects of low fluid shear stress (FSS ≤ 2 dyn/cm²) against interleukin-1β (IL-1β)-induced chondrocyte apoptosis and explored the underlying molecular mechanisms.

METHODS

Chondrocytes were cultured under four conditions: control, IL-1β stimulation, low FSS, and combined low FSS + IL-1β stimulation. Apoptosis was assessed using Hoechst staining and flow cytometry. Western blotting determined the expression of caspase-3 (CASP3), caspase-8 (CASP8), and NF-κB p65. Quantitative real-time PCR measured miR-143-3p expression. The roles of miR-143-3p and the extracellular signal-regulated kinase 5 (ERK5)/Krüppel-like factor 4 (KLF4) signaling pathway were further investigated using miR-143-3p mimics and inhibitors, an ERK5 inhibitor, and a KLF4 overexpression vector.

RESULTS

IL-1β induced significant chondrocyte apoptosis, which was markedly inhibited by low FSS. Mechanistically, low FSS suppressed miR-143-3p expression, thereby enhancing ERK5 signaling. This activated ERK5 subsequently upregulated KLF4 expression, further mitigating IL-1β-induced damage. Importantly, miR-143-3p overexpression under low FSS conditions exacerbated IL-1β-induced apoptosis, while miR-143-3p inhibition attenuated it. Consistent with this, ERK5 inhibition augmented IL-1β-induced apoptosis, whereas KLF4 overexpression suppressed it.

CONCLUSION

Low FSS protects chondrocytes from IL-1β-induced apoptosis by suppressing miR-143-3p and activating the ERK5/KLF4 signaling pathway. This study reveals a novel mechanism by which mechanical stimulation protects cartilage.

Shuanglongjiegu pill promoted bone marrow mesenchymal stem cell osteogenic differentiation by regulating the miR-217/RUNX2 axis to activate Wnt/β-catenin pathway

This study aimed to investigate the effects of Shuanglongjiegu pill (SLJGP) on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and explore its mechanism based on miR-217/RUNX2 axis. Results found that drug-containing serum of SLJGP promoted BMSCs viability with a dose-dependent effect. Under osteogenic differentiation conditions, SLJGP promoted the expression of ALP, OPN, BMP2, RUNX2, and the osteogenic differentiation ability of BMSCs. In addition, SLJGP significantly reduced miR-217 expression, and miR-217 directly targeted RUNX2. After treatment with miR-217 mimic, the promoting effects of SLJGP on proliferation and osteogenic differentiation of BMSCs were significantly inhibited. MiR-217 mimic co-treated with pcDNA-RUNX2 further confirmed that the miR-217/RUNX2 axis was involved in SLJGP to promote osteogenic differentiation of BMSCs. In addition, analysis of Wnt/β-catenin pathway protein expression showed that SLJGP activated the Wnt/β-catenin pathway through miR-217/RUNX2. In conclusion, SLJGP promoted osteogenic differentiation of BMSCs by regulating miR-217/RUNX2 axis and activating Wnt/β-catenin pathway.

Analysis of the predictive value of microRNA-199b-5p combined with nitric oxide for venous thrombosis in patients undergoing total knee arthroplasty

BACKGROUND

Deep vein thrombosis (DVT) of lower extremity is a common complications after total knee arthroplasty (TKA). The purpose of this study was to evaluate the risk factors for DVT after TKA and analyze the expression of miR-199b-5p and nitric oxide (NO) before and after TKA, as well as their predictive value for DVT.

METHODS

Basic clinical information of 121 patients with TKA was analyzed retrospectively. RT-qPCR was used to detect the relative expression level of miR-199b-5p in patients before and after TKA treatment. Based on the occurrence of DVT, patients were divided into DVT and non-DVT groups. Logistic regression analysis evaluated the risk factors of DVT. The receiver operating characteristic (ROC) curve assessed the predictive value of postoperative miR-199b-5p level, preoperative NO level, and their combination in DVT. The target genes of miR-199b-5p and their functions were predicted and annotated using bioinformatics analysis.

RESULTS

The level of miR-199b-5p after TKA was upregulated compared with that before TKA (P < 0.001). DVT occurred in 20 of 121 patients after TKA, with an incidence of 16.53%. Multivariate analysis showed that age, family history of DVT, decrease of NO and increase of miR-199b-5p were risk factors for DVT after TKA (P < 0.05). The ROC curve showed that both miR-199b-5p and NO had certain diagnostic value for DVT, but the combination of miR-199b-5p and NO had the highest diagnostic accuracy (P < 0.001).

CONCLUSION

This study showed that the expression of miR-199b-5p was up-regulated after TKA, and miR-199b-5p levels were higher in DVT patients than in non-DVT patients. miR-199b-5p combined with NO is of great value in the diagnosis of DVT after TKA.

MiR-331-3p facilitates osteoporosis and may promote osteoporotic fractures by modulating NRP2 expression

BACKGROUND

Osteoporosis (OP) is a high-incidence bone disease that is prone to osteoporotic fractures (OF), so it has attracted widespread attention.

AIM

This study investigated the specific expression and role of miR-331 in patients with OP and OF. The findings have profound implications for the clinical prevention and treatment of these conditions.

METHODS

The study included 60 OP patients, 46 OF patients, and 40 healthy controls. The expression level of miR-331-3p was detected using RT-qPCR. BMP2 was used to stimulate differentiation in MC3T3-E1 cells. After induction, the expression activity of osteogenic differentiation-related gene markers was detected using RT-qPCR. The target gene analysis was conducted using a luciferase reporter assay.

RESULTS

The levels of miR-331-3p were significantly elevated, while NRP2 levels were significantly reduced in OF patients. Post-surgery, miR-331-3p levels decreased over time. MiR-331-3p was found to negatively regulate the luciferase activity of NPR2 in MC3T3-E1 cells. Furthermore, overexpression of miR-331-3p inhibited cell proliferation and decreased the levels of osteoblast differentiation markers.

CONCLUSION

The up-regulation of miR-331-3p can promote OP and might also encourage the occurrence of OF by regulating NRP2. However, this needs further verification.

mir-744-5p inhibits cell growth and angiogenesis in osteosarcoma by targeting NFIX

BACKGROUND

Osteosarcoma (OS) is a malignant bone tumor that commonly occurs in children and adolescents under the age of 20. Dysregulation of microRNAs (miRNAs) is an important factor in the occurrence and progression of OS. MicroRNA miR-744-5p is aberrantly expressed in various tumors. However, its roles and molecular targets in OS remain unclear.

METHODS

Differentially expressed miRNAs in OS were analyzed using the Gene Expression Omnibus dataset GSE65071, and the potential hub miRNA was identified through weighted gene co-expression network analysis. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of miR-744-5p in OS cell lines. In vitro experiments, including CCK-8 assays, colony formation assays, flow cytometry apoptosis assays, and tube formation assays, were performed to explore the effects of miR-744-5p on OS cell biological behaviors. The downstream target genes of miR-744-5p were predicted through bioinformatics, and the binding sites were validated by a dual-luciferase reporter assay.

RESULTS

The lowly expressed miRNA, miR-744-5p, was identified as a hub miRNA involved in OS progression through bioinformatic analysis. Nuclear factor I X (NFIX) was confirmed as a direct target for miR-744-5p in OS. In vitro studies revealed that overexpression of miR-744-5p could restrain the growth of OS cells, whereas miR-744-5p inhibition showed the opposite effect. It was also observed that treatment with the conditioned medium from miR-744-5p-overexpressed OS cells led to poorer proliferation and angiogenesis in human umbilical vein endothelial cells (HUVECs). Furthermore, NFIX overexpression restored the suppression effects of miR-744-5p overexpression on OS cell growth and HUVECs angiogenesis.

CONCLUSION

Our results indicated that miR-744-5p is a potential tumor-suppressive miRNA in OS progression by targeting NFIX to restrain the growth of OS cells and angiogenesis in HUVECs.

Long non-coding TRPM2-AS regulates fracture healing by targeting miR-545-3p/Bmp2

OBJECTIVE

Delayed fracture healing increases the suffering of patients. An in-depth investigation of the pathogenesis of delayed fracture healing may offer new direction for the prevention and treatment.

METHODS

The study included 63 normal healing tibial fractures and 58 delayed healing tibial fractures patients. Long non-coding RNA (lncRNA)TRPM2-AS, microRNA-545-3p (miR-545-3p), bone morphogenetic protein 2 (Bmp2) mRNA and osteogenic differentiation markers, including runt-related transcription factor 2 (Runx2), osteocalcin (Ocn), and alkaline phosphatase (Alp) mRNA expression were determined by Real-time quantitative reverse transcription-polymerase chain reaction in serum and MC3T3-E1 cells. The prediction potential of TRPM2-AS in delayed healing fracture patients was verified by receiver operating characteristic curves. The binding relationship of TRPM2-AS/miR-545-3p/Bmp2 was evaluated by dual luciferase reporter gene assay. Cell proliferation and apoptosis were detected by CCK-8 and flow cytometry.

RESULTS

TRPM2-AS was remarkably down-regulated in patients with delayed fracture healing and could better predict the fracture healing status. TRPM2-AS downregulation inhibited osteogenic markers mRNA expression, restrained proliferation, and promoted apoptosis of MC3T3-E1 cells (p < 0.05). In delayed fracture healing, miR-545-3p was dramatically up-regulated and was negatively regulated by TRPM2-AS. Reducing miR-545-3p eliminate the negative effect of TRPM2-AS down-regulation on osteoblast proliferation and differentiation (p < 0.05). miR-545-3p targets Bmp2, which plays a positive role in osteoblast differentiation (p < 0.05).

CONCLUSION

This study found that TRPM2-AS has the potential to be a diagnostic marker for delayed fracture healing and revealed that the TRPM2-AS/miR-545-3p/Bmp2 axis affects fracture healing by regulating osteoblast.

Exosomes derived from mir-337-3p over-expressing tendon stem cells protect against apoptosis of tenocytes via targeting caspase3

BACKGROUND

Tendons are important dense fibrous structures connecting muscle to bone, and tendon stem cells (TDSCs) affect their repair and regeneration. The role of TDSC-derived exosomes (TDSC-Exos) is still being unexplored; therefore, this study aimed to investigate the protective effect of TDSC-Exos on tenocytes.

METHODS

The TDSCs and tenocytes were all derived from Sprague Dawley (SD) rats. The expression of positive and negative markers of TDSCs were detected by flow cytometry, and the multi-differentiation ability was also detected to identify TDSCs. Exos were derived from TDSCs using ultracentrifugation; furthermore, Exos enriched with microRNA(miR)-377-3p were generated from TDSCs stably overexpressing miR-377-3p after transfection, identified with transmission electron microscopy (TEM), western blot and PKH26 staining assay. Moreover, the cell functions of tenocytes were evaluated by MTT, EdU, transwell, and flow cytometry. Dual luciferase reporter and RNA pull-down assays were used to verify the binding sites of miR-337-3p and caspase3 (CASP3) predicted by Targetscan.

RESULTS

Exos (miR-337-3p) were taken up by tenocytes, and promoted the proliferation, migration, and invasion and suppressed the apoptosis of tenocytes in a dose-dependent manner. Bioinformatics analysis showed that CASP3 was a target of miR-377-3p, which was further verified by luciferase and RNA pull-down assays. Moreover, over-expressed CASP3 reversed the effects of Exos (miR-337-3p) on cell functions of tenocytes.

CONCLUSIONS

Our findings suggest that Exos derived from miR-337-3p over-expressing TDSCs could potentially protect against tenocyte apoptosis by regulating CASP3. This novel therapeutic approach holds promise for the treatment of tendon injury, offering a glimmer of hope for improved patient outcomes.

SP1 regulates BMSC osteogenic differentiation through the miR-133a-3p/MAPK3 axis : SP1 regulates osteogenic differentiation of BMSCs

BACKGROUND

The progression of osteoporosis (OP) can dramatically increase the risk of fractures, which seriously disturb the life of elderly individuals. Specific protein 1 (SP1) is involved in OP progression. However, the mechanism by which SP1 regulates OP progression remains unclear.

OBJECTIVE

This study investigated the mechanism underlying the function of SP1 in OP.

METHODS

SAMP6 mice were used to establish an in vivo model of age-dependent OP, and BALB/c mice were used as controls. BMSCs were extracted from two subtypes of mice. Hematoxylin and eosin staining were performed to mark the intramedullary trabecular bone structure to evaluate histological changes. ChIP assay was used to assess the targeted regulation between SP1 and miR-133a-3p. The binding sites between MAPK3 and miR-133a-3p were verified using a dual-luciferase reporter assay. The mRNA levels of miR-133a-3p and MAPK3 were detected using quantitative reverse transcription polymerase chain reaction (RT-qPCR). The protein expression of SP1, MAPK3, Colla1, OCN, and Runx2 was examined using Western blotting. Alkaline phosphatase (ALP) kit and Alizarin Red S staining were used to investigate ALP activity and mineralized nodules, respectively.

RESULTS

The levels of SP1 and miR-133a-3p were upregulated, whereas the expression of MAPK3 was downregulated in BMSCs from SAMP6 mice, and miR-133a-3p inhibitor accelerated osteogenic differentiation in BMSCs. SP1 directly targeted miR-133a-3p, and MAPK3 was the downstream mRNA of miR-133a-3p. Mechanically, SP1 accelerated osteogenic differentiation in BMSCs via transcriptional mediation of the miR-133a-3p/MAPK3 axis.

CONCLUSION

SP1 regulates osteogenic differentiation by mediating the miR-133a-3p/MAPK3 axis, which would shed new light on strategies for treating senile OP.

LncRNA MAGI2-AS3 promotes fracture healing through downregulation of miR-223-3p

BACKGROUND

Long non-coding RNAs (LncRNAs) are recognized as a pivotal element in the processes of fracture healing and the osteogenic differentiation of stem cells. This study investigated the molecular mechanism and regulatory significance of lncRNA MAGI2-AS3 (MAGI2-AS3) in fracture healing.

METHODS

Serum levels of MAGI2-AS3 in patients with normal and delayed fracture healing were verified by RT-qPCR assays. The predictive efficacy of MAGI2-AS3 for delayed fracture healing was analyzed by ROC curve. Osteogenic markers were quantified by RT-qPCR assays. MC3T3-E1 cell viability was detected using CCK-8 assay, and flow cytometry was utilized to measure cell apoptosis. The dual-luciferase reporter gene assay was used to determine the targeted binding between MAGI2-AS3 and miR-223-3p.

RESULTS

Serum MAGI2-AS3 expression was decreased in patients with delayed fracture healing compared with patients with normal healing. Elevated MAGI2-AS3 resulted in an upregulation of the proliferative capacity of MC3T3-E1 cells and a decrease in mortality, along with increased levels of both osteogenic markers. However, after transfection silencing MAGI2-AS3, the trend was reversed. Additionally, miR-223-3p was the downstream target of MAGI2-AS3 and was controlled by MAGI2-AS3. miR-223-3p mimic reversed the promoting effects of MAGI2-AS3 overexpression on osteogenic marker levels and cell growth, and induced cell apoptosis.

CONCLUSION

The upregulation of MAGI2-AS3 may expedite the healing of fracture patients by targeting miR-223-3p, offering a novel biomarker for diagnosing patients with delayed healing.

Long non-coding RNA MIAT serves as a biomarker of fragility fracture and promotes fracture healing

BACKGROUND

Fragility fracture is common in the elderly. Osteoblast differentiation is essential for bone healing and regeneration. Expression pattern of long non-coding RNA MIAT during fracture healing was examined, and its role in osteoblast differentiation was investigated.

METHODS

90 women with simple osteoporosis and 90 women with fragility fractures were included. Another 90 age-matched women were set as the control group. mRNA levels were tested using RT-qPCR. Cell viability was detected via CCK-8, and osteoblastic biomarkers, including ALP, OCN, Collagen I, and RUNX2 were tested via ELISA. The downstream miRNAs and genes targeted by MIAT were predicted by bioinformatics analysis, whose functions and pathways were annotated via GO and KEGG analysis.

RESULTS

Serum MIAT was upregulated in osteoporosis women with high accuracy of diagnostic efficacy. Serum MIAT was even elevated in the fragility fracture group, but decreased in a time manner after operation. MIAT knockdown promoted osteogenic proliferation and differentiation of MC3T3-E1, but the influences were reversed by miR-181a-5p inhibitor. A total of 137 overlapping target genes of miR-181a-5p were predicted based on the miRDB, TargetScan and microT datasets, which were mainly enriched for terms related to signaling pathways regulating pluripotency of stem cells, cellular senescence, and osteoclast differentiation.

CONCLUSIONS

LncRNA MIAT serves as a promising biomarker for osteoporosis, and promotes osteogenic differentiation via targeting miR-181a-5p.

miR-27b-3p reduces muscle fibrosis during chronic skeletal muscle injury by targeting TGF-βR1/Smad pathway

BACKGROUND

Fibrosis is a significant pathological feature of chronic skeletal muscle injury, profoundly affecting muscle regeneration. Fibro-adipogenic progenitors (FAPs) have the ability to differentiate into myofibroblasts, acting as a primary source of extracellular matrix (ECM). the process by which FAPs differentiate into myofibroblasts during chronic skeletal muscle injury remains inadequately explored.

METHOD

mouse model with sciatic nerve denervated was constructed and miRNA expression profiles between the mouse model and uninjured mouse were analyzed. qRT/PCR and immunofluorescence elucidated the effect of miR-27b-3p on fibrosis in vivo and in vitro. Dual-luciferase reporter identified the target gene of miR-27b-3p, and finally knocked down or overexpressed the target gene and phosphorylation inhibition of Smad verified the influence of downstream molecules on the abundance of miR-27b-3p and fibrogenic differentiation of FAPs.

RESULT

FAPs derived from a mouse model with sciatic nerves denervated exhibited a progressively worsening fibrotic phenotype over time. Introducing agomiR-27b-3p effectively suppressed fibrosis both in vitro and in vivo. MiR-27b-3p targeted Transforming Growth Factor Beta Receptor 1 (TGF-βR1) and the abundance of miR-27b-3p was negatively regulated by TGF-βR1/Smad.

CONCLUSION

miR-27b-3p targeting the TGF-βR1/Smad pathway is a novel mechanism for regulating fibrogenic differentiation of FAPs. Increasing abundance of miR-27b-3p, suppressing expression of TGF-βR1 and inhibiting phosphorylation of smad3 presented potential strategies for treating fibrosis in chronic skeletal muscle injury.

Upregulation of circ_0076684 in osteosarcoma facilitates malignant processes by mediating miRNAs/CUX1

Circular RNAs (circRNAs) are a newly appreciated type of endogenous noncoding RNAs that play vital roles in the development of various human cancers, including osteosarcoma (OS). In this study, we investigated three circRNAs (circ_0076684, circ_0003563, circ_0076691) from the RUNX Family Transcription Factor 2 (RUNX2) gene locus in OS. We found that the expression of circ_0076684, circ_0003563, circ_0076691, and RUNX2 mRNA is upregulated in OS, which is a consequence of CBX4-mediated transcriptional activation. Among these three RUNX2-circRNAs, only circ_0076684 is significantly associated with the clinical features and prognosis of OS patients. Functional experiments indicate that circ_0076684 promotes OS progression in vitro and in vivo. Circ_0076684 acts as a sponge for miR-370-3p, miR-140-3p, and miR-193a-5p, raising Cut Like Homeobox 1 (CUX1) expression by sponging these three miRNAs. Furthermore, we presented that circ_0076684 facilitates OS progression via CUX1. In conclusion, this study found that the expression of three circRNAs and RUNX2 mRNA from the RUNX2 gene locus is significantly upregulated in OS, as a result of CBX4-mediated transcriptional activation. Circ_0076684 raises CUX1 expression by sponging miR-370-3p, miR-140-3p, and miR-193a-5p, and facilitates OS progression via CUX1.

Circ_0044235 regulates the development of osteoarthritis by the modulation of miR-375/PIK3R3 axis

BACKGROUND

Circular RNAs (circRNAs) play an important role in osteoarthritis (OA). However, the role of circRNA in OA is still unclear. Here, we explored the role and mechanism of circ_0044235 in OA.

METHODS

CHON-001 cells were treated with IL-1β to establish OA model in vitro. The levels of circ_0044235, miR-375 and phosphoinositide 3-kinase (PI3K) regulatory subunit 3 (PIK3R3) were detected by quantitative real-time PCR. Cell count kit-8 assay and flow cytometry assay were used to detect cell viability and apoptosis. The concentrations of inflammation factors were determined by enzyme-linked immunosorbent assay. Western blot was used to detect protein levels. The interaction between miR-375 and circ_0044235 or PIK3R3 was analyzed by dual-luciferase reporter assay and RNA immunoprecipitation assay.

RESULTS

Circ_0044235 was significantly decreased in OA cartilage tissue and IL-1β-treated CHON-001 cells. Overexpression of circ_0044235 promoted IL-1β-stimulated CHON-001 cell viability and inhibited apoptosis, inflammation, and extracellular matrix (ECM) degradation. In mechanism analysis, circ_0044235 could act as a sponge for miR-375 and positively regulate PIK3R3 expression. In addition, miR-375 ameliorated the effect of circ_0044235 overexpression on IL-1β-mediated CHON-001 cells injury. In addition, miR-375 inhibition mitigated IL-1β-induced CHON-001 cell injury, while PIK3R3 silencing restored the effect.

CONCLUSION

Circ_0044235 knockdown alleviated IL-1β-induced chondrocytes injury by regulating miR-375/PIK3R3 axis, confirming that circ_0044235 might be a potential target for OA treatment.