Dysregulated MiR-3150a-3p Promotes Lumbar Intervertebral Disc Degeneration by Targeting Aggrecan.

BACKGROUND/AIMS: Low back pain has become one of the most common musculoskeletal diseases in the world. Studies have shown that intervertebral disc degeneration (IDD) is an important factor leading to low back pain, but the mechanisms underlying IDD remain largely unknown. Research over the past decade has suggested critical roles for microRNAs (miRNAs) in natural growth and disease progression. However, it remains poorly understood whether circular RNAs participate in IDD. METHODS: Clinical IDD samples were collected from 20 patients who underwent discectomy. Weighted gene co-expression network analysis was used to identify the co-expression miRNA network modules (highly co-expressed clusters of miRNAs) that were associated with IDD grade. RESULTS: miR-3150a-3p was the most significantly up-regulated miRNA in module "Blue." Notably, aggrecan (ACAN) was identified as a direct target gene of miR-3150a-3p and ACAN expression was regulated by miR-3150a-3p. Overexpression of miR-3150a-3p decreased ACAN expression in nucleus pulposus cells, whereas inhibition of miR-3150a-3p increased ACAN expression. In addition, ACAN expression was negatively correlated with IDD grade. CONCLUSION: Our study suggests that the reduction of ACAN expression induced by the upregulation of miR-3150a-3p might participate in the development of IDD.

miR-145-5p Increases Osteoclast Numbers In Vitro and Aggravates Bone Erosion in Collagen-Induced Arthritis by Targeting Osteoprotegerin.

BACKGROUND Osteoprotegerin (OPG) inhibits bone resorption and binds with strong affinity to receptor activator of NF κB ligand (RANKL), thereby preventing RANKL from binding to its receptor RANK. Osteoclasts have documented effects on bone erosion of rheumatoid arthritis (RA). The aim of this study was to examine the role of miR-145-5p in the regulation of RA osteoclast differentiation and bone erosion. MATERIAL AND METHODS Expression of microRNA-145-5p in human peripheral blood mononuclear cells (PBMC) and synovial tissue was assayed by real-time polymerase chain reaction (RT-PCR). OPG, RANK, and RANKL expression in RAW-264.7 cells was examined by RT-PCR and Western blot analysis. Osteoclast formation was detected by tartrate-resistant acid phosphatase (TRAP) staining. The effect of miR-145-5p on predicted target mRNAs was examined by luciferase reporter assays. Collagen-induced arthritis (CIA) was induced by injecting DBA/1 mice with bovine type II collagen (CII), and miR-145-5p agomir was administered by intravenous injection. Morphological changes in the CIA joint were assessed by micro-computed tomography (CT) and histopathology. RESULTS miR-145-5p levels significantly increased in RA PBMC and synovial tissue compared with normal PBMC and osteoarthritis (OA) tissue. After transfection of RAW-264.7 cells with miR-145-5p, RANK and RANKL expression increased significantly, while OPG expression decreased significantly. TRAP staining results showed osteoclast numbers increased. Micro-CT analysis of the arthritic joints showed that the miR-145-5p agomir caused bone erosion in mice, and histopathological analysis revealed that miR-145-5p agomir aggravates cartilage erosion. CONCLUSIONS Our findings indicate that administration of miR-145-5p aggravates joint erosion in CIA mice. This suggests that miR-145-5p is a potential target for the treatment of RA.

Long non-coding RNA small nucleolar RNA host gene 12 (SNHG12) promotes cell proliferation and migration by upregulating angiomotin gene expression in human osteosarcoma cells.

The long non-coding RNA (lncRNA) small nucleolar RNA host gene 12 (SNHG12) has a role in cell proliferation and migration. Angiomotin, encoded by the AMOT gene, is a protein that regulates the migration and organization of endothelial cells. SNHG12 and AMOT have been shown to play a role in a variety of human cancers but have yet to be studied in detail in human osteosarcoma. Tissue samples from primary osteosarcoma (n = 20) and adjacent normal tissues (n = 20), the osteosarcoma cell lines, SAOS-2, MG-63, U-2 OS, and the human osteoblast cell line hFOB (OB3) were studied using Western blot for angiomotin, and quantitative real-time polymerase chain reaction for the expression of SNHG12 and AMOT. The expression of SNHG12 was knocked down using RNA interference. Cell migration assays were performed. Cell apoptosis was studied using flow cytometry. SNHG12 and AMOT messenger RNA (mRNA) expression was upregulated in osteosarcoma tissues and cell lines when compared with normal tissues and cells. Upregulation of AMOT mRNA was associated with upregulation of SNHG12. Knockdown of SNHG12 reduced the expression of angiomotin in osteosarcoma cells and suppressed cell proliferation and migration but did not affect cell apoptosis. This preliminary study has shown that the lncRNA SNHG12 promotes cell proliferation and migration by upregulating AMOT gene expression in osteosarcoma cells in vivo and in vitro. Further studies are recommended to investigate the role of SNHG12 and AMOT expression in tumor cell proliferation and migration and angiogenesis in osteosarcoma and a range of malignant mesenchymal tumors.

Cryptococcosis of lumbar vertebra in a patient with rheumatoid arthritis and scleroderma: case report and literature review.

BACKGROUND: Although cryptococcosis mainly occurs in the central nervous system and lungs in immunocompromised hosts, it can involve any body site or structure. Here we report the first case of primary cryptococcosis of a lumbar vertebra without involvement of the central nervous system or lungs in a relatively immunocompromised individual with rheumatoid arthritis and scleroderma. CASE PRESENTATION: A 40-year-old Chinese woman with rheumatoid arthritis diagnosed 1 year beforehand and with a subsequent diagnosis of scleroderma was found to have an isolated cryptococcal infection of the fourth lumbar vertebra. Her main complaints were severe low back and left leg pain. Cryptococcosis was diagnosed by CT-guided needle biopsy and microbiological confirmation; however, serum cryptococcal antigen titer was negative. After 3 months of antifungal therapy with fluconazole the patient developed symptoms and signs of scleroderma, which was confirmed on laboratory tests. After taking fluconazole for 6 months, the progressive destruction of the lumbar vertebral body had halted and the size of an adjacent paravertebral mass had decreased substantially. On discharge symptoms had resolved and at an annual follow-up there was no evidence of recurrence on the basis of symptoms, signs or imaging investigations. CONCLUSION: Although cryptococcosis of the lumbar vertebra is extremely rare, it should be considered in the differential diagnosis for patients with lumbar vertebral masses to avoid missed diagnosis, misdiagnosis and diagnostic delay. Early treatment with antifungals proved to be a satisfactory alternative to surgery in this relatively immunocompromised patient. Any residual spinal instability can be treated later, once the infection has resolved.

Mendelian Randomization Study of Lipid Metabolites Reveals Causal Associations with Heel Bone Mineral Density.

BACKGROUND: Osteoporosis, which is a bone disease, is characterized by low bone mineral density and an increased risk of fractures. The heel bone mineral density is often used as a representative measure of overall bone mineral density. Lipid metabolism, which includes processes such as fatty acid metabolism, glycerol metabolism, inositol metabolism, bile acid metabolism, carnitine metabolism, ketone body metabolism, sterol and steroid metabolism, etc., may have an impact on changes in bone mineral density. While some studies have reported correlations between lipid metabolism and heel bone mineral density, the overall causal relationship between metabolites and heel bone mineral density remains unclear. OBJECTIVE: to investigate the causal relationship between lipid metabolites and heel bone mineral density using two-sample Mendelian randomization analysis. METHODS: Summary-level data from large-scale genome-wide association studies were extracted to identify genetic variants linked to lipid metabolite levels. These genetic variants were subsequently employed as instrumental variables in Mendelian randomization analysis to estimate the causal effects of each lipid metabolite on heel bone mineral density. Furthermore, metabolites that could potentially be influenced by causal relationships with bone mineral density were extracted from the KEGG and WikiPathways databases. The causal associations between these downstream metabolites and heel bone mineral density were then examined. Lastly, a sensitivity analysis was conducted to evaluate the robustness of the results and address potential sources of bias. RESULTS: A total of 130 lipid metabolites were analyzed, and it was found that acetylcarnitine, propionylcarnitine, hexadecanedioate, tetradecanedioate, myo-inositol, 1-arachidonoylglycerophosphorine, 1-linoleoylglycerophoethanolamine, and epiandrosterone sulfate had a causal relationship with heel bone mineral density (p < 0.05). Furthermore, our findings also indicate an absence of causal association between the downstream metabolites associated with the aforementioned metabolites identified in the KEGG and WikiPathways databases and heel bone mineral density. CONCLUSION: This work supports the hypothesis that lipid metabolites have an impact on bone health through demonstrating a causal relationship between specific lipid metabolites and heel bone mineral density. This study has significant implications for the development of new strategies to osteoporosis prevention and treatment.

Analysis on the risk factors of second fracture in osteoporosis-related fractures.

OBJECTIVE: To explore the clinical characteristics and risk factors of refracture in patients suffering from osteoporosis-related fractures as well as effective interventions. METHODS: From January 2006 to January 2008, both out-patients and in-patients in our hospital who were over 50 years old and suffered from osteoporosis-related fractures were selected for this research. They were divided into fracture group and refracture group. The refracture rate was followed up for 2 years, during which 11 patients developed refracture, thus were included in the refracture group. Therefore, 273 patients, 225 first-fracture cases, aged (67.7+/-8.5) years, and 48 refracture cases, aged (72.7+/-9.5) years, were included in this study. General data including age and sex, fracture types, femoral neck bone mineral density (BMD) T-scores tested by dual-energy X-rays absorptiometry (DEXA), Charlson index, time-frame between two fractures as well as mobility skill assessment were collected and analyzed by single-factor and multivariate statistical methods. RESULTS: Females accounted for 70.2% of the fracture group and 77.1% of the refracture group. The most common refracture type was vertebral fracture for the first time and femoral neck fracture for the second time during the follow-up. The second fracture happened 3.7 years after the first one on average. The refracture rate was 2.12% within one year, and 4.66% within two years. Risk factors for a second fracture in osteoporotic fracture patients included age (larger than 75 years, HR equal to 1.23, 95%CI 1.18-1.29; larger than 85 years, HR equal to 1.68, 95% CI 1.60-1.76), female sex (HR equal to 1.36, 95%CI 1.32-1.40), prior vertebral fractures (HR equal to 1.62, 95%CI 1.01-2.07), prior hip fractures (HR equal to 1.27, 95%CI 0.89-2.42), BMD T-score less than -3.5 (HR equal to 1.38, 95%CI 1.17-1.72) and weakened motor skills (HR equal to 1.27, 95%CI 1.09-1.40). CONCLUSIONS: The risks of second fracture among patients with initial brittle fracture are substantial. There is adequate time between the first and second fractures for interventions to reduce the risks of refracture, especially for the old women with a vertebral or hip fracture. Medication, motor functional rehabilitation and fall-down prevention training are helpful.

Identification of a circRNA-miRNA-mRNA network to explore the effects of circRNAs on pathogenesis and treatment of spinal cord injury.

AIMS: Many studies have demonstrated that circRNAs are closely associated with human diseases. Nonetheless, the potential mechanism by which circRNAs impacts spinal cord injury (SCI) is not fully understood. The aim of this study was to explore the regulatory roles of circRNAs in SCI. MAIN METHODS: The sequencing data of circRNA, miRNA and mRNA were obtained from Gene Expression Omnibus (GEO) datasets. Candidates were identified to construct a circRNA-miRNA-mRNA network based on circRNA-miRNA interactions and miRNA-mRNA interactions. Protein-protein interactions (PPI) analysis was performed to determine hub genes, and a connectivity map (CMap) analysis was applied to determine potential therapeutic targets for SCI. KEY FINDINGS: A total of 1656 differentially expressed circRNAs (DEcircRNAs), 71 differentially expressed miRNAs (DEmiRNAs) and 2782 differentially expressed mRNAs (DEmRNAs) were identified. We integrated four overlapped circRNAs, six miRNAs and 101 target mRNAs into a circRNA-miRNA-mRNA network. We next identified two hub genes (DDIT4, EZR) based on the PPI network and identified five circRNA-miRNA-hub gene regulatory axes. In addition, we discovered three chemicals (tanespimycin, fulvestrant, carbamazepine) as potential treatment options for SCI. SIGNIFICANCE: Our study suggests a regulatory role for circRNAs in the pathogenesis and treatment of SCI from the view of a competitive endogenous RNA (ceRNA) network.

MicroRNA­381/Hes1 is a potential therapeutic target for spinal cord injury.

The aim of the present study was to investigate whether microRNA­381 is a potential therapeutic target for spinal cord injury (SCI) and its possible mechanism. Reverse transcription quantitative polymerase chain reaction (qPCR) for mRNA expression was used to analyze the changes of microRNA-381 expression. Cell viability and cell apoptosis were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. Caspase­3 activity was measured using caspase­3 activity kit, and western blot analysis was used to measure the protein expression of neurogenic locus notch homolog protein 1 (Notch1), notch 1 intracellular domain (NICD) and transcription factor HES-1 (Hes1). The data showed that microRNA­381 expression of model SCI rats was downregulated compared with that of control rats. Overexpression of microRNA­381 promoted cell proliferation, and inhibited apoptosis and caspase­3 and apoptosis regulator BAX (Bax) protein expression in neurocytes. Overexpression of microRNA­381 also increased Wnt and ß­catenin protein expression, and suppressed the protein expression of Notch1, NICD and Hes1 in neurocytes. Wnt inhibitor, Wnt­C59 (1 µmol/l), inhibited cell proliferation, promoted apoptosis and caspase­3 and Bax protein expression, suppressed ß­catenin protein expression and induced Hes1 protein expression in neurocytes following microRNA­381 overexpression. Notch inhibitor, FLI­06 (1 µmol/l), promoted cell proliferation, inhibited apoptosis and caspase­3 and Bax protein expression, and suppressed NICD and Hes1 protein expression in neurocytes following microRNA­381 overexpression. Thus, this study showed that overexpression of microRNA­381 promotes cell proliferation of neurocytes in SCI via Hes1 expression, which may be a novel important mechanism for SCI in clinical applications.

Transforaminal endoscopic discectomy versus conventional microdiscectomy for lumbar discherniation: a systematic review and meta-analysis.

BACKGROUND: The open microdiscectomy is the most common surgical procedure for the decompression of radiculopathy caused by lumbar disk herniation. To date, a variety of minimally invasive (MI) techniques have been developed. In the last decades, endoscopic techniques have been developed to perform discectomy. The transforaminal endoscopic discectomy (TED) with posterolateral access evolved out of the development of endoscopic techniques. METHODS: A systematic literature search was performed using the PubMed, EMBASE, and Cochrane Library databases for trials written in English. The randomized trials and observational studies that met our inclusion criteria were subsequently included. Two reviewers respectively extracted data and estimated the risk of bias. All statistical analyses were performed using Review Manager 5.3. RESULTS: Five prospective and four retrospective studies involving 1527 patients were included. The results of the meta-analysis indicated that there were significant differences between the two groups in length of hospital stay (MD = - 8.41, 95% CI - 10.26, - 6.56; p value < 0.00001). However, there were no significant differences in the leg visual analog scale (VAS) scores, the Oswestry Disability Index (ODI) scores, and the incidence of complications and recurrence. CONCLUSIONS: The transforaminal endoscopic discectomy is superior to open microdiscectomy in the length of hospital stay. However, there were no differences in leg pain, functional recovery, and incidence of complications between TED and MD in treating LDH.

Effect of BMPs and Wnt3a co-expression on the osteogenetic capacity of osteoblasts.

In the present study, third­generation autologous­inactivated bone morphogenic protein 2 (BMP2), BMP4, BMP6, BMP7, BMP9 and Wnt3a lentiviral vectors were constructed and integrated into the genome of MC3T3­E1 murine mesenchymal stem cells (MMSCs) to produce osteoinductive factor gene­modified MMSCs. The transfection efficiency of each osteoinductive factor was then determined by detecting the expression levels of runt related transcription factor 2 (Runx2) mRNA. The cotransfection with combinations of two lentiviruses was performed, and the expression levels of bone γ­carboxyglutamate protein and alkaline phosphatase in the MC3T3­E1 cell culture supernatant were detected. The expression level of Runx2 mRNA was detected by reverse transcription­polymerase chain reaction, and western blotting was performed to detect the protein expression levels of BMP2, BMP4, BMP6, BMP7, BMP9 and Wnt3a. The results demonstrated that the recombinant lentiviruses were successfully transfected into MC3T3­E1 cells. The relative expression levels of Runx2 mRNA were greatest in the BMP2 group, sequentially followed by the BMP4, BMP9, BMP7, Wnt3a and BMP6 groups. The results of cotransfection of MC3T3­E1 cells (a total of 8 groups) demonstrated that BMP­2 and BMP­7 exhibited the highest cotransfection efficiency. Western blot analysis demonstrated that following BMP2 and BMP7 cotransfection of MC3T3­E1 cells, the protein expression levels of BMP2, BMP4, BMP6, BMP7, BMP9 and Wnt3a were increased compared with control cells. In conclusion, the third­generation lentiviral vectors effectively improved the osteogenic efficiencies of MC3T3­E1 cells, which provided an important theoretical basis and therapeutic strategy for bone reconstruction and tissue engineering.

MicroRNA-497 inhibits cell proliferation, migration, and invasion by targeting AMOT in human osteosarcoma cells.

MicroRNAs (miRNAs) have a role in the development and progression of human malignancy. The expression of miR-497 is decreased in malignant tumors, which suggests a role for miR-497 as a tumor suppressor. Angiomotin is encoded by the AMOT gene, which is a target for miR-497. Angiomotin has a role in angiogenesis, cell proliferation, and invasion in human malignancies, including osteosarcoma. However, the role of miR-497 in human osteosarcoma is unknown. This preliminary study included human osteosarcoma tissues and normal tissues from 20 patients, the osteosarcoma cell lines, MG-63, SAOS-2, U-2 OS, and the human osteoblast cell line hFOB (OB3). Western blots for angiomotin and quantitative real-time polymerase chain reaction for the expression of miR-497 and AMOT were performed. Knockdown studies were performed using RNA interference and transfection studies used miR-497 mimics. Quantitative cell migration assays were performed, and cell apoptosis was studied by flow cytometry. Osteosarcoma cells and cell lines showed reduced expression of miR-497 and increased expression of angiomotin. Transfection of osteosarcoma cells with miR-497 mimics suppressed the expression of angiomotin. Results from a dual-luciferase reporter system supported AMOT as a direct target gene of miR-497. Knockdown of AMOT using RNA interference resulted in inhibition of osteosarcoma cell proliferation, migration, and invasion. These preliminary studies support a role for miR-497 as a suppressor of AMOT gene expression in human osteosarcoma cells, resulting in suppression of tumor cell proliferation and invasion. Further studies are recommended to investigate the role of miR-497 in osteosarcoma and other malignant mesenchymal tumors.