MicroRNA Expression Profiling of Bone Marrow Mesenchymal Stem Cells in Steroid-Induced Osteonecrosis of the Femoral Head Associated with Osteogenesis

Asiatic acid prevents glucocorticoid-induced femoral head osteonecrosis via PI3K/AKT pathway

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) represents a predominant etiology of non-traumatic osteonecrosis, imposing substantial pain, restricting hip mobility, and diminishing overall quality of life for affected individuals. Centella asiatica (L.) Urb. (CA), an herbal remedy deeply rooted in traditional oriental medicine, has exhibited noteworthy therapeutic efficacy in addressing inflammation and facilitating wound healing. Drawing from CA's historical applications, its anti-inflammatory, anti-apoptotic, and antioxidant attributes may hold promise for managing GIONFH. Asiatic acid (AA), a primary constituent of CA, has been substantiated as a key contributor to its anti-apoptotic, antioxidant, and anti-inflammatory capabilities, showcasing a close association with orthopedic conditions. For the investigation of whether AA could alleviate GIONFH through suppressing oxidative stress, apoptosis, and to delve into its potential cellular and molecular mechanisms, the connection between AA and disease was analyzed through network pharmacology. DEX-induced apoptosis in rat osteoblasts and GIONFH in rat models, got utilized for the verification in vitro/vivo, on underlying mechanism of AA in GIONFH. Network pharmacology analysis reveals a robust correlation between AA and GIONFH in multiple target genes. AA has demonstrated the inhibition of DEX-induced osteoblast apoptosis by modulating apoptotic factors like BAX, BCL-2, Cleaved-caspase3, and cleaved-caspase9. Furthermore, it effectively diminishes the ROS overexpression and regulates oxidative stress through mitochondrial pathway. Mechanistic insights suggest that AA's therapeutic effects involve phosphatidylinositol 3-kinase/Protein kinase B (PI3K/AKT) pathway activation. Additionally, AA has exhibited its potential to ameliorate GIONFH progression in rat models. Our findings revealed that AA mitigated DEX-induced osteoblast apoptosis and oxidative stress through triggering PI3K/AKT pathway. Also, AA can effectively thwart GIONFH occurrence and development in rats.

Regulatory mechanisms of circular RNAs during human mesenchymal stem cell osteogenic differentiation

Human osteogenic differentiation is a complex and well-orchestrated process which involves a plethora of molecular players and cellular processes. A growing number of studies have underlined that circular RNAs (circRNAs) play an important regulatory role during human osteogenic differentiation. CircRNAs are single-stranded, covalently closed non-coding RNA molecules that are acquiring increased attention as epigenetic regulators of gene expression. Given their intrinsic high conformational stability, abundance, and specificity, circRNAs can undertake various biological activities in order to regulate multiple cellular processes, including osteogenic differentiation. The most recent evidence indicates that circRNAs control human osteogenesis by preventing the inhibitory activity of miRNAs on their downstream target genes, using a competitive endogenous RNA mechanism. The aim of this review is to draw attention to the currently known regulatory mechanisms of circRNAs during human osteogenic differentiation. Specifically, we provide an understanding of recent advances in research conducted on various human mesenchymal stem cell types that underlined the importance of circRNAs in regulating osteogenesis. A comprehensive understanding of the underlying regulatory mechanisms of circRNA in osteogenesis will improve knowledge on the molecular processes of bone growth, resulting in the potential development of novel preclinical and clinical studies and the discovery of novel diagnostic and therapeutic tools for bone disorders.

Circ_0058792 regulates osteogenic differentiation through miR-181a-5p/Smad7 axis in steroid-induced osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) caused by steroids is a severe orthopedic disorder resulting from the use of high-dose steroid drugs, characterized by structural changes in the bone, joint dysfunction, and femoral head collapse. CircRNAs and miRNAs have increasingly been suggested to play pivotal roles in osteogenic differentiation and osteogenesis. Significant upregulation of circ_0058792 was observed in patients with steroid-induced ONFH. Bioinformatic analysis showed that circ_0058792 might act as a sponge for miR-181a-5p. This study further investigated the mechanisms underlying the role of circ_0058792 and miR-181a-5p in osteogenic differentiation in methylprednisolone-induced ONFH rats and MC3T3-E1 cells. The results showed a notable decrease in the serum of miR-181a-5p in methylprednisolone-induced ONFH rats. Silencing of circ_0058792 using siRNAs and overexpression of miR-181a-5p significantly increased alkaline phosphatase activity and matrix mineralization capacity. Additionally, markers for osteogenic differentiation were significantly upregulated in miR-181a-5p-transfected cells. However, overexpression of circ_0058792 and the addition of the miR-181a-5p inhibitor reversed this increase. Smad7 was identified to be miR-181a-5p's direct target and circ_0058792 was confirmed to be miR-181a-5p's competing endogenous RNA (ceRNA). Upregulation of miR-181a-5p promotes phosphorylation of Smad2 and Smad3. Furthermore, circ_0058792 and miR-181a-5p had opposing effects on Smad7 expression. Collectively, these findings indicate that circ_0058792 regulates osteogenic differentiation by sponging miR-181a-5p via the TGF-β/Smad7 pathway. These findings elucidated the functions of circ_0058792 and miR-181a-5p in the regulation of steroid-induced ONFH. Our findings also indicated that circ_0058792 and miR-181a-5p are possible diagnostic markers and therapeutic targets for treating steroid-induced ONFH.

hsa_circ_0058122 knockdown prevents steroid-induced osteonecrosis of the femoral head by inhibiting human umbilical vein endothelial cells apoptosis via the miR-7974/IGFBP5 axis

BACKGROUND

Steroid-induced osteonecrosis of femoral head (SONFH) is a serious complication of glucocorticoid overused. Recent evidence has demonstrated that circRNAs exert key pathophysiological roles in a variety of disease processes. However, the role of circRNA in SONFH remains largely unknown. The current study sought to evaluate how hsa_circ_0058122 affects SONFH in dexamethasone (DEX) treated human umbilical vein endothelial cells (HUVECs) model.

METHODS

RT-PCR was used to demonstrate the hsa_circ_0058122 expression level in Dex-treated HUVECs cells. The effects of hsa_circ_0058122 on HUVECs apoptosis were evaluated via overexpression plasmid and siRNA. Using dual-luciferase and fluorescence in situ hybridization assays, we demonstrated that hsa_circ_0058122 binds to miR-7974 thereby facilitating HUVECs apoptosis. Bioinformatics analysis and western blot were performed to confirm target genes of hsa-miR-7974.

RESULTS

In our previous work, we revealed the top 20 elevated circRNAs in SONFH patients were hsa_circ_0010027, hsa_circ_0058115, hsa_circ_0010026, hsa_circ_0058839, hsa_circ_0056886, hsa_circ_0056885, hsa_circ_0058146, hsa_circ_0058105, hsa_circ_0058112, hsa_circ_0058143, hsa_circ_0058102, hsa_circ_0058090, hsa_circ_0075353, hsa_circ_0058126, hsa_circ_0058130, hsa_circ_0058140, hsa_circ_0058122, hsa_circ_0058123, hsa_circ_0058103, and hsa_circ_0058121. Among these, hsa_circ_0058122 was finally selected for further investigation. We found hsa_circ_0058122 expression was markedly elevated in Dex-treated HUVECs cells, and the Dex-mediated HUVEC apoptosis was impaired in hsa_circ_0058122-silenced cells and increased in hsa_circ_0058122-overexpressing cells. hsa_circ_0058122 competitively binds to hsa-miR-7974, which in turn interacts with insulin-like growth factor binding protein 5 (IGFBP5).

CONCLUSIONS

hsa_circ_0058122/miR-7974/IGFBP5 was proposed to be a key regulatory pathway for SONFH. DEX treatment upregulated hsa_circ_0058122 expression in HUVECs, which sponged miR-7974, thereby increasing IGFBP5 expression, the hsa_circ_0058122/miR-7974/IGFBP5 axis contributed to the Dex-mediated apoptosis. These findings may identify novel targets for SONFH molecular therapy.

Bone Mesenchymal Stem Cells (BMSCs) Transplantation Can Repair Rat Femoral Head Necrosis and Inhibit the Expression of Omgp

To study the therapeutic effect of BMSCs on femoral head necrosis and whether it can inhibit the growth of OMgP. 15 healthy rats were divided into ZZ group (normal group), GT group (femoral head necrosis) and MM group (BMSCs transplantation). At 1 h, 3 h, 1 d, and 3 d, the expression of OMgP in GT group were higher than ZZ group (P <0.05) and MM group, indicating that BMSCs transplantation can decreased OMgP expression. At 1 d, 7 d, and 14 d, BBB scores of the GT group were lower than ZZ group (P < 0.05) and MM group (P < 0.05), indicating that BMSCs transplantation can improve spinal cord injury behavior. The cells in ZZ group were well stained and morphologically intact, the femoral head was not damaged, and the articular surface was smooth, GT group had cartilage necrosis with disordered inferior epiphysis, and the femoral head of the MM group had less damage and increased osteoblasts. The blood vessel counts in necrotic area in GT group were higher than ZZ group and MM group with decreased new bone area in repair area compared to ZZ and MM group (P <0.05), indicating that the area of femoral head necrosis after BMSCs transplantation was improved. The levels of ALP and BGP in GT group were lower than ZZ group (P <0.05) and MM group (P <0.05). Bone marrow mesenchymal stem cell transplantation can effectively repair new bone area, up-regulate ALP and BGP, and have a positive effect on femoral head necrosis, possibly by inhibiting OMGP activity.

Study on the Mechanism of BMSCs in Regulating NF-κB Signal Pathway by Targeting miR-449a to Improve the Inflammatory Response to Peripheral Nerve Injury

OBJECTIVE

To evaluate the mechanism of Bone Marrow Mesenchymal Stem Cells (BMSCs) in regulating NF-κB signal pathway by targeting miR-449a.

METHODS

Stem cells were transfected by over-expressing and inhibiting miR-449a to detect the levels and viability of miR-449a in stem cells after transfection. Stem cells and neurons were co-cultured in vitro to evaluate the in vitro mechanism of stem cells over-expressing miR-449a on neurons.

RESULTS

After the addition of neurons, the neuronal activity of miR-449a over-expression group increased significantly, the expression of NF-κB signal pathway proteins (IκBα, p50, and p65) decreased, and the inflammatory cytokines (TNF-α and IL-1β) decreased significantly (P<0.05). In vivo experiments in rats also showed that rats were unresponsive, did not chirp or elude after being stimulated. After stem cell therapy, the weight and response of rats gradually returned to normal levels. miR-449a expression significantly increased in the stem cell + miR-449a over-expression group, expression of NF-κB signal pathway proteins (IκBα, p50, and p65) decreased, inflammatory cytokines (TNF-α and IL-1β) significantly decreased, and cell activity significantly increased (P<0.05).

CONCLUSIONS

BMSCs can modulate NF-κB signaling pathway by targeting miR-449a, so as to reduce the inflammatory response to peripheral nerve injury and repair nerve injury.

The Emerging Role of MicroRNAs in Bone Diseases and Their Therapeutic Potential

MicroRNAs (miRNAs) are a class of small (20-24 nucleotides), highly conserved, non-coding RNA molecules whose main function is the post-transcriptional regulation of gene expression through sequence-specific manners, such as mRNA degradation or translational repression. Since these key regulatory molecules are implicated in several biological processes, their altered expression affects the preservation of cellular homeostasis and leads to the development of a wide range of pathologies. Over the last few years, relevant investigations have elucidated that miRNAs participate in different stages of bone growth and development. Moreover, the abnormal expression of these RNA molecules in bone cells and tissues has been significantly associated with the progression of numerous bone diseases, including osteoporosis, osteosarcoma, osteonecrosis and bone metastasis, among others. In fact, miRNAs regulate multiple pathological mechanisms, including altering either osteogenic or osteoblast differentiation, metastasis, osteosarcoma cell proliferation, and bone loss. Therefore, in this present review, aiming to impulse the research arena of the biological implications of miRNA transcriptome in bone diseases and to explore their potentiality as a theragnostic target, we summarize the recent findings associated with the clinical significance of miRNAs in these ailments.

Neohesperidin promotes the proliferation and osteogenic differentiation of BMSCs via BMP2-Wnt/β-catenin pathway

The present study aimed to investigate the role of neohesperidin (NH) in mice with steroid-induced femoral head necrosis (SONFH) and in bone marrow stromal cells (BMSCs). The SONFH model was established. The effects of NH on SONFH mice were detected by hematoxylin-eosin (HE) staining and micro-CT, while those on proliferation, osteogenic differentiation and associated pathways of BMSCs were detected by molecular experiments. Besides, the effects of NH on β-catenin nuclear translocation and the H3K27me3 abundance on the transcriptional start site of Bone Morphogenetic Protein 2 (BMP2) were also determined by immunofluorescence staining and Chromatin Immunoprecipitation. Results indicated that NH not only reduced histopathological changes and improved the structures of the femoral heads of the SONFH mice but also promoted the proliferation and osteogenic differentiation of mouse BMSCs, enhanced alkaline phosphatase (ALP) activity, and upregulated expressions of osteoblast markers in a dose-dependent manner. Moreover, NH was also confirmed to upregulate the expressions of genes related to osteogenesis and Wnt/β-catenin pathway of BMSCs, which, however, were all noticeably downregulated by Noggin and DKK1. Additionally, Noggin and DKK1 in combination further promoted the suppressive effect on genes related to osteogenesis and Wnt/β-catenin pathway than alone. Besides, NH induced nuclear translocation of β-catenin in BMSCs and further reduced H3K27me3-triggered enrichment of BMP2. In conclusion, NH could promote proliferation and osteogenic differentiation of BMSCs via BMP2-Wnt/β-catenin pathway.

Circ_0134944 inhibits osteogenesis through miR-127-5p/PDX1/SPHK1 pathway

Introduction

Osteoporosis, a common skeletal disorder mainly affecting postmenopausal women, is characterized by the imbalance between osteogenesis and osteoclastogenesis. Circ_0134944 has been recently found to be upregulated in postmenopausal osteoporosis (PMOP) patients. However, its role in osteogenesis remains unknown. Here we aimed to explore the role of circ_0134944 in osteogenesis and reveal the underlying mechanism.

Methods

qRT-PCR was used to determine the expression of circ_0134944, miR-127-5p, PDX1 and SPHK1 in the blood mononuclear cells (BMCs) of PMOP patients. Bone marrow mesenchymal stem cells (BMSCs) were used as the cellular model. Western blotting and qRT-PCR were used to determine the expression of osteogenesis-related genes (Runx2, OPN, OCN). ALP and Alizarin Red S staining were performed to evaluate osteogenic differentiation. The interactions between circ_0134944 and miR-127-5p, miR-127-5p and PDX1, PDX1 and SPHK1 were determined by dual-luciferase reporter and ChIP assay.

Results

Circ_0134944, PDX1 and SPHK1 were upregulated while miR-127-5p was downregulated in PMOP patients. Enhanced expression of circ_0134944 suppressed osteogenesis, which was then reversed by miR-127-5p overexpression. The binding between circ_0134944 and miR-127-5p, PDX1 and miR-127-5p were confirmed by dual-luciferase reporter assay. Moreover, PDX1 was enriched in the promoter region of SPHK1, and SPHK1 overexpression prevented the promotion of osteogenesis induced by miR-127-5p overexpression.

Conclusions

Taken together, these results demonstrate that circ_0134944 inhibit osteogenesis via miR-127-5p/PDX1/SPHK1 axis. Thus, the present study offered evidence that circ_0134944/miR-127-5p/PDX1/SPHK1 axis could be a potential therapeutic target for PMOP.

miR-452-3p inhibited osteoblast differentiation by targeting Smad4

Osteoblast differentiation is a complex process that is essential for normal bone formation. A growing number of studies have shown that microRNAs (miRNAs) are key regulators in a variety of physiological and pathological processes, including osteogenesis. In this study, BMP2 was used to induce MC3T3-E1 cells to construct osteoblast differentiation cell model. Then, we investigated the effect of miR-452-3p on osteoblast differentiation and the related molecular mechanism by RT-PCR analysis, Western blot analysis, ALP activity, and Alizarin Red Staining. We found that miR-452-3p was significantly downregulated in osteoblast differentiation. Overexpression miR-452-3p (miR-452-3p mimic) significantly inhibited the expression of osteoblast marker genes RUNX2, osteopontin (OPN), and collagen type 1 a1 chain (Col1A1), and decreased the number of calcium nodules and ALP activity. In contrast, knockdown miR-452-3p (miR-452-3p inhibitor) produced the opposite effect. In terms of mechanism, we found that Smad4 may be the target of miR-452-3p, and knockdown Smad4 (si-Smad4) partially inhibited the osteoblast differentiation enhanced by miR-452-3p. Our results suggested that miR-452-3p plays an important role in osteoblast differentiation by targeting Smad4. Therefore, miR-452-3p is expected to be used in the treatment of bone formation and regeneration.

LRRC17 regulates the bone metabolism of human bone marrow mesenchymal stem cells from patients with idiopathic necrosis of femoral head through Wnt signaling pathways: A preliminary report

Idiopathic necrosis of the femoral head (INFH) is a common disease with unknown cause. Its successful treatment relies on the repair of the necrotic bone. The application of autologous mesenchymal stem cells (MSCs) has shown great promise in saving the patients from undergoing total hip arthroplasty. Leucine-rich repeat-containing 17 (LRRC17) is less expressed in patients with femoral head necrosis and LRRC17 can inhibit bone degradation. However, it remains unknown whether LRRC17 plays a role in the pathogenesis of INFH. The present study aimed to investigate the potential role and mechanism of LRRC17 in the pathogenesis and treatment of INFH. It was found that despite the similar cell morphology and MSC surface marker expressions of human bone marrow MSCs (BMSCs) isolated from patients with INFH (INFH-hBMSC) and femoral neck fracture (FNF) (FNF-hBMSC), INFH-hBMSC had higher percentage of apoptosis (P<0.05), as well as lower osteogenic potential and higher adipogenic potential (both P<0.05). However, there was no difference in cell proliferation between FNF-hBMSC and INFH-hBMSC (P>0.05). It was also confirmed that the expression of LRRC17 was lower in the bone tissue and hBMSCs from patients with INFH compared with patients with FNF (P<0.05). Overexpression of LRRC17 promoted osteogenesis and inhibited the adipogenesis in hBMSCs, accompanied with the increase of Wnt3a and β-catenin expressions, and the decrease of Wnt5a and receptor activator of nuclear factor κ-B ligand (Rankl) expressions (all, P<0.05). Furthermore, knockout of LRRC17 in hBMSCs inhibited the expression levels of osteogenic and promoted adipogenic markers, while decreasing Wnt3a and β-catenin expressions, and increasing Wnt5a and Rankl expressions (all, P<0.05). The present preliminary study suggested that imbalanced bone metabolism may be involved in the pathogenesis of INFH. The modulation of the LRRC17 gene may delay or even restore the balance of osteogenic and adipogenic differentiation in autologous BMSCs derived from patients with INFH, providing a new target for the treatment of INFH.

Reciprocal effect of microRNA-224 on osteogenesis and adipogenesis in steroid-induced osteonecrosis of the femoral head

The adverse effects of glucocorticoids (GCs) on bone marrow stromal stem cells (BMSCs) play an important role in steroid-induced osteonecrosis of the femoral head (ONFH). Our previous miRNA microarray analysis indicated that microRNA-224-5p (miR-224-5p) could be a potential regulator; however, the underlying mechanism remains unclear. In the present study, we demonstrated that miR-224-5p was upregulated in GC-treated BMSCs, and functional experiments revealed that miR-224-5p could suppress osteogenic but promote adipogenic differentiation of BMSCs. Smad4 was identified as a direct target gene of miR-224-5p, and the Smad4-Taz axis was confirmed as the regulatory pathway for adipo-osteogenic differentiation of BMSCs. Our in vivo experiments further confirmed that the miR-224-5p antagomir could alleviate the inhibitory effects of GCs and facilitate bone formation in steroid-induced ONFH models. Therefore, these findings provide insight into the function of miR-224-5p as a reciprocal regulator of the adipo-osteogenic differentiation of BMSCs, and it could serve as a novel therapeutic target for steroid-induced ONFH.

Integrated analysis of miRNA and mRNA transcriptomic reveals antler growth regulatory network

The growth of antler is driven by endochondral ossification in the growth center of the apical region. Antler grows faster than cancer tissues, but it can be stably regulated and regenerated periodically. To elucidate the molecular mechanisms of how antler grows rapidly without carcinogenesis, in this study, we used RNA-seq technology to evaluate the changes of miRNA and mRNA profiles in antler at four different developmental stages, including 15, 60, 90, and 110 days. We identified a total of 55004 unigenes and 246 miRNAs of which, 10182, 13258, 10740 differentially expressed (DE) unigenes and 35, 53, 27 DE miRNAs were identified in 60-day vs. 15-day, 90-day vs. 60-day, and 110-day vs. 90-day. GO and KEGG pathway analysis indicated that DE unigenes and DE miRNA were mainly associated with chondrogenesis, osteogenesis and inhibition of oncogenesis, that were closely related to antler growth. The interaction networks of mRNA-mRNA and miRNA-mRNA related to chondrogenesis, osteogenesis and inhibition of oncogenesis of antler were constructed. The results indicated that mRNAs (COL2A1, SOX9, WWP2, FGFR1, SPARC, LOX, etc.) and miRNAs (miR-145, miR-199a-3p, miR-140, miR-199a-5p, etc.) might have key roles in chondrogenesis and osteogenesis of antler. As well as mRNA (TP53, Tpm3 and ATP1A1, etc.) and miRNA (miR-106a, miR-145, miR-1260b and miR-2898, etc.) might play important roles in inhibiting the carcinogenesis of antler. In summary, we constructed the mRNA-mRNA and miRNA-mRNA regulatory networks related to chondrogenesis, osteogenesis and inhibition of oncogenesis of antler, and identified key candidate mRNAs and miRNAs among them. Further developments and validations may provide a reference for in-depth analysis of the molecular mechanism of antler growth without carcinogenesis.

Evidence-Supported HBO Therapy in Femoral Head Necrosis: A Systematic Review and Meta-Analysis

Although many studies have shown that hyperbaric oxygen (HBO) therapy can significantly improve symptoms and quality of life of patients affected by femoral head necrosis, this therapy is not worldwide approved yet. This meta-analysis was performed to evaluate its clinical effect. Relevant studies published before May 2020 were systematically searched using terms related to HBO and femoral head necrosis. Fixed and random-effects models were used to estimate the odds ratio (OR) with 95% confidence intervals (CI). Subgroup analyses and publication bias tests were carried out to explore potential study heterogeneity and bias. Ten studies involving 353 controls and 368 HBO-treated cases were included, most of which were conducted on Asian population. The clinical effect in the HBO therapy group was 3.84 times higher than in the control group (OR = 3.84, 95% CI (2.10, 7.02), p < 0.00001). Subgroup analyses showed that the clinical effect of HBO therapy was statistically significant in the Asian subpopulation which represented most of the subjects (OR = 3.53, 95% CI (1.87, 6.64), p < 0.00001), but not in the non-Asian subpopulation, probably because of insufficient numerosity (OR = 7.41, 95% CI (0.73, 75.71), p = 0.09). The results of this meta-analysis suggest that patients with femoral head necrosis treated with HBO therapy can achieve a significant clinical improvement.

CircRNA_25487 inhibits bone repair in trauma-induced osteonecrosis of femoral head by sponging miR-134-3p through p21

We aimed to identify specific circular RNAs (circRNAs) involved in bone repair of trauma-induced osteonecrosis of femoral head (TIONFH) and to explore the potential mechanism. CircRNA sequencing on the blood sample collected from patients with and without TIONFH was performed to select cirRNAs that were significantly differentially expressed, followed by qRT-PCR confirmation. Furthermore, the functions of one selected circRNA and the potential mechanisms in bone repair of TIONFH were validated based on the bone marrow mesenchymal stem cells (BMSCs) and osteoclast-like cells (OLCs) through CCK-8, flow cytometry, transwell assay, luciferase reporter assay, and western blot. A total of 234 upregulated and 148 downregulated differentially expressed circRNAs were identified, and qRT-PCR showed that circRNA_25487 was significantly upregulated in the peripheral blood of TIONFH patients. Luciferase reporter assay confirmed the binding effect between miR-134-3p and circRNA_25487. CircRNA_25487 suppression and miR-134-3p overexpression could promote cell proliferation and invasion while inhibited apoptosis of BMSCs and OLCs. miR-134-3p could target p21. CircRNA_25487 inhibited bone repair in TIONFH by sponging miR-134-3p to upregulate the expression of p21.

cAMP regulates 11β-hydroxysteroid dehydrogenase-2 and Sp1 expression in MLO-Y4/MC3T3-E1 cells

11β-hydroxysteroid dehydrogenase-2 (11β-HSD2) is one of the key enzymes in glucocorticoid metabolism, which can inactivate local corticosterone and regulate the level of active glucocorticoid in tissues. The expression of 11β-HSD2 and its regulatory pathway serve an important role in the apoptosis of steroid induced osteonecrosis of the femoral head (SANFH). The present study aimed to identify the regulatory effects of cAMP on the expression of Sp1 transcription factor (Sp1) and 11β-HSD2 in osteocytes at the cellular level. Murine long bone osteocyte Y4 (MLO-Y4) clone cells and mouse embryo osteoblast-like (MC3T3-E1) cells were cultured in vitro with adenylate cyclase activator or inhibitor (forskolin and SQ22536, respectively) to investigate the effects of alterations to intracellular cAMP levels. mRNA and protein expression levels of Sp1 and 11β-HSD2 were detected by reverse transcription-quantitative PCR and western blotting, respectively. Compared with the negative control group, the mRNA and protein expression levels of Sp1 were significantly increased in the activation group, whereas Sp1 expression levels were significantly decreased in the inhibition group. Similarly, compared with the negative control group, the mRNA and protein expression levels of 11β-HSD2 were significantly increased in the activator group, but significantly decreased in the inhibitor group. The aforementioned results indicated that intracellular cAMP levels significantly regulated the expression of Sp1 and 11β-HSD2 in mouse osteocytes and osteoblasts. Therefore, the present study suggested a potential therapeutic strategy for the prevention of osteonecrosis of the femoral head.

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today?: A 5-Year Update

➢. Clinicians should exercise a high level of suspicion in at-risk patients (those who use corticosteroids, consume excessive alcohol, have sickle cell disease, etc.) in order to diagnose osteonecrosis of the femoral head in its earliest stage. ➢. Nonoperative treatment modalities have generally been ineffective at halting progression. Thus, nonoperative treatment is not appropriate in early stages when one is attempting to preserve the native joint, except potentially on rare occasions for small-sized, medially located lesions, which may heal without surgery. ➢. Joint-preserving procedures should be attempted in early-stage lesions to save the femoral head. ➢. Cell-based augmentation of joint-preserving procedures continues to show promising results, and thus should be considered as an ancillary treatment method that may improve clinical outcomes. ➢. The outcomes of total hip arthroplasty in the setting of osteonecrosis are excellent, with results similar to those in patients who have an underlying diagnosis of osteoarthritis.

Microarray profiling of circular RNAs in steroid-associated osteonecrosis of the femoral head: Observational study

The aim of this study was to elucidate the molecular mechanisms and to identify the differential expression of circular RNAs (circRNAs) for steroid-associated osteonecrosis of the femoral head (SONFH) using bioinformatics analysis.circRNA microarray was performed with 3 SONFH tissues and the adjacent normal tissues, and differentially expressed circRNA were identified by limma package in R. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery database. In addition, a differentially expressed genes (DEG)-associated circRNA/microRNA (miRNA) interaction was predicted by combination of TargetScan and miRanda, and the circRNA/miRNA interaction network generated by the cytoscape software.A total of 647 differentially expressed circRNAs, including 433 upregulated and 214 downregulated circRNA were identified. The most enriched GO terms for upregulated and downregulated circRNA were extracellular matrix organization and leukocyte activation in biological process; extracellular matrix and spindle pole in cellular component; integrin binding and ATP binding in molecular function, and KEGG pathway enrichment analyses showed that the upregulated and downregulated circRNA were strongly associated with Protein digestion and absorption and Cell cycle. Moreover, a total of 212 differentially expressed messenger RNAs (mRNAs), including 113 upregulated and 99 downregulated genes were identified. In addition, from the analysis of miRNA, long noncoding RNAs, mRNA, and circRNA networks, we found that hsa_circ_0008136 and hsa_circ_0074758 were respectively the upregulated and downregulated circRNA with highest degrees.The identified circRNA and mRNA could be implicated in the progression of human SONFH. The findings could lead to a better understanding of SONFH pathogenesis.

Identification of key microRNAs and target genes for the diagnosis of bone nonunion

A number of recent studies have highlighted the causes of bone nonunion (BN), however, the rate of BN incidence continues to rise and available therapeutic options to treat this condition remain limited. Thus, to prevent disease progression and improve patient prognosis, it is vital that BN, or the risk thereof, be accurately identified in a timely manner. In the present study, bioinformatics analyses were used to screen for the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) between patients with BN and those with bone union, using data from the Gene Expression Omnibus database. Furthermore, clinical samples were collected and analyzed by reverse transcription‑quantitative PCR and western blotting. In vitro and in vivo experiments were carried out to confirm the relationship between BN and the DEGs of interest, in addition to being used to explore the underlying molecular mechanism of BN. Functional enrichment analysis of the downregulated DEGs revealed them to be enriched for genes associated with 'ECM‑receptor interactions', 'focal adhesion', 'and the calcium signaling pathway'. When comparing DEM target genes with these DEGs, nine DEGs were identified as putative DEM targets, where hsa‑microRNA (miR)‑1225‑5p‑CCNL2, hsa‑miR‑339‑5p‑PRCP, and hsa‑miR‑193a‑3p‑mitogen‑activated protein kinase 10 (MAPK10) were the only three pairs which were associated with decreased gene expression levels. Furthermore, hsa‑miR‑193a‑3p was demonstrated to induce BN by targeting MAPK10. Collectively, the results of the present study suggest that hsa‑miR‑193a‑3p may be a viable biomarker of BN.

Serum exosomal hsa-miR-135b-5p serves as a potential diagnostic biomarker in steroid-induced osteonecrosis of femoral head

Accumulating studies have demonstrated serum exosomal microRNAs (miRNAs) represent novel biomarkers for various diseases. In this study, we aimed to explore the feasibility of using serum exosomal miRNAs as novel serological biomarkers for steroid-induced osteonecrosis of femoral head (SONFH). We identified the characters of exosomes which were obtained from fresh serum of 5 systemic lupus erythematosus (SLE) patients without SONFH, 5 SLE patients with SONFH (SLE-SONFH) and 5 healthy ones. Comprehensive exosomal miRNA sequencing was performed to profile the differentially expressed miRNAs in the three groups. We then validated the expression levels of selected miRNAs by qRT-PCR. Furthermore, KEGG pathway, GO annotation, protein-protein interaction (PPI) network, module analysis and miRNAs-mRNAs interaction network were built to analyze the potential targets and mechanism. Sequencing data conveyed that hsa-miR-135b-5p, hsa-miR-150-5p, hsa-miR-509-3-5p, hsa-miR-514a-3p and hsa-miR-708-5p were significantly differentially expressed in the three groups. The results of qRT-PCR for the first time confirmed that the expression of hsa-miR-135b-5p was strikingly up-regulated in SLE-SONFH group which were consistent with miRNA sequencing results. In addition, bioinformatics analysis indicated that the enriched functions and pathways of the most differentially expressed miRNAs including Wnt, MAPK as well as Hippo signaling pathway. The top five hub genes (FGF2, PTEN, HACE1, VAMP2, and CBL) were part of module of the PPI network, which consisted of 713 nodes and 2191 edges. In conclusion, this study provides a novel and fundamental serum exosomal miRNAs profile of SONFH and hsa-miR-135b-5p may be identified as a unique diagnostic biomarker for SONFH.

Noncoding RNAs in Steroid-Induced Osteonecrosis of the Femoral Head

Steroid-induced osteonecrosis of the femoral head (ONFH) is a severe orthopedic disease caused by the long-term administration of glucocorticoids. The main pathological feature of ONFH is the gradually progressive necrosis of bone cells and the bone marrow, ultimately resulting in structural changes or even complete collapse of the femoral head. However, the exact pathogenic mechanism of ONFH remains unknown. Noncoding RNAs (ncRNAs) have emerged as very powerful regulators of gene expression, functioning at both transcriptional and posttranscriptional levels in the pathogenesis of ONFH. Here, we review the current knowledge of the role of ncRNAs, including microRNAs, long noncoding RNAs, and circular RNAs, in the pathogenesis of steroid-induced ONFH. Further focus and validation of these associations can provide new insight into the pathogenic mechanisms at the molecular level to suggest targets for treatment and prevention.

Upregulating MicroRNA-410 or Downregulating Wnt-11 Increases Osteoblasts and Reduces Osteoclasts to Alleviate Osteonecrosis of the Femoral Head

BACKGROUND

Little is known regarding the functional role of microRNA-410 (miR-410) in osteonecrosis of the femoral head (ONFH); hence, the aim of the present study was to investigate miR-410 targeting Wnt-11 to modulate the osteogenic and osteoclastic mechanism in the prevention of ONFH.

METHODS

Fifteen ONFH samples and 15 normal samples were gathered. The pathological changes of the femoral head, osteoblasts, and osteoclasts in the clinical samples were observed. The rat model of ONFH was injected with agomir-miR-410, Wnt-11-siRNA, or oe-Wnt-11. MiR-410; Wnt-11; osteoblast-related factors alkaline phosphatase (ALP), bone gamma-carboxyglutamate protein (BGLAP), and Collα1 expression; and osteoclast-related factors acid phosphatase 5 (ACP5), cathepsin K (CTSK), and MMP9, as well as Bcl-2 and Bax expression, were tested by RT-qPCR and western blot analysis. The osteogenic function index ALP and OCN together with osteoclast function index NTX-1 and CTX-1 in serum was tested by ELISA.

RESULTS

MiR-410, ALP, BGLAP, and Collα1 degraded as well as Wnt-11, ACP5, CTSK, and MMP9 enhanced in ONFH tissues of the clinical samples. Upregulated miR-410 and downregulated Wnt-11 enhanced bone mineral density (BMD) and BV/TV of rats, heightened the BMD level of the femoral shaft, femoral head, and spinal column, and also raised the serum calcium and phosphorus levels of rats, while restrained apoptosis of osteocytes, elevated OCN, ALP, BGLAP, and Collα1 expression and declined ACP5, CTSK, NTX-1, CTX-1, and MMP9 expression in rats.

CONCLUSION

This study suggested that upregulating miR-410 or downregulating Wnt-11 increases osteoblasts and reduces osteoclasts to alleviate the occurrence of ONFH. Thus, miR-410 may serve as a potential target for the treatment of ONFH.

The Role of MicroRNAs in Early Chondrogenesis of Human Induced Pluripotent Stem Cells (hiPSCs)

Human induced pluripotent stem cells (hiPSCs) play an important role in research regarding regenerative medicine. Particularly, chondrocytes differentiated from hiPSCs seems to be a promising solution for patients suffering from osteoarthritis. We decided to perform chondrogenesis in a three-week monolayer culture. Based on transcriptome analysis, hiPSC-derived chondrocytes (ChiPS) demonstrate the gene expression profile of cells from early chondrogenesis. Chondrogenic progenitors obtained by our group are characterized by significantly high expression of Hox genes, strongly upregulated during limb formation and morphogenesis. There are scanty literature data concerning the role of microRNAs in early chondrogenesis, especially in chondrogenic differentiation of hiPSCs. The main aim of this study was to investigate the microRNA expression profile and to select microRNAs (miRNAs) taking part in early chondrogenesis. Our findings allowed for selection crucial miRNAs engaged in both diminishing pluripotency state and chondrogenic process (inter alia hsa-miR-525-5p, hsa-miR-520c-3p, hsa-miR-628-3p, hsa-miR-196b-star, hsa-miR-629-star, hsa-miR-517b, has-miR-187). These miRNAs regulate early chondrogenic genes such as: HOXD10, HOXA11, RARB, SEMA3C. These results were confirmed by RT-qPCR analysis. This work contributes to a better understanding of the role of miRNAs directly involved in chondrogenic differentiation of hiPSCs. These data may result in the establishment of a more efficient protocol of obtaining chondrocyte-like cells from hiPSCs.

Roles for miRNAs in osteogenic differentiation of bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs), which were first discovered in bone marrow, are capable of differentiating into osteoblasts, chondrocytes, fat cells, and even myoblasts, and are considered multipotent cells. As a result of their potential for multipotential differentiation, self-renewal, immune regulation, and other effects, BMSCs have become an important source of seed cells for gene therapy, tissue engineering, cell replacement therapy, and regenerative medicine. MicroRNA (miRNA) is a highly conserved type of endogenous non-protein-encoding RNA of about 19-25 nucleotides in length, whose transcription process is independent of other genes. Generally, miRNA plays roles in regulating cell proliferation, differentiation, apoptosis, and development by binding to the 3' untranslated region of target mRNAs, whereby they can degrade or induce translational silencing. Although miRNAs play a regulatory role in various metabolic processes, they are not translated into proteins. Several studies have shown that miRNAs play an important role in the osteogenic differentiation of BMSCs. Herein, we describe in-depth studies of roles for miRNAs during the osteogenic differentiation of BMSCs, as they provide new theoretical and experimental rationales for bone tissue engineering and clinical treatment.

Effects of microRNA-195 on the Prognosis of Glioma Patients and the Proliferation and Apoptosis of Human Glioma Cells

Glioma is the most common and aggressive intracranial malignant tumor with poor prognosis. Acts as a tumor suppressor, microRNA-195 (miR-195) plays important roles in a variety of cancers. However, the expression of miR-195 and role of miR-195 in glioma are still not well understood. 186 patients with glioma were enrolled and the follow-up period ranges from 1 to 69 months. MiR-195 was exogenously transfected into human glioma U87 cell line. The cell proliferation assay (CCK-8), colony formation assay, cell cycle analysis and cell apoptosis analysis were examined to investigate miR-195 effect on U87 cells. MiR-195 levels were reversely correlated with pathological grades (r = -0.487, p = 0.003). For patients with low miR-195 levels, their median survival time was 15 months, whereas the median survival time in patients with high miR-195 levels was 56.53 months. Multi-factor Cox regression analysis showed that high level of miR-195 (Odds ratio (OR): 0.347, 95% CI: 0.121-0.992) was associated with decreased mortality risk of patients. Moreover, overexpression of miR-195 inhibits proliferation and colony formation, and induces apoptosis of U87 cells. MiR-195 could block the glioma cells in G0/G1 phase, reducing S phase cells and regulating apoptosis related proteins (Caspase-3, Caspase-8, Caspase-9 and Bcl-2). Downregulation of miR-195 was associated with poor prognosis in human glioma. MiR-195 acted as tumor suppressor through inhibiting cell proliferation and promoting cell apoptosis via blockade of cell cycle and regulation of apoptosis related proteins.

CircUSP45 inhibited osteogenesis in glucocorticoid-induced osteonecrosis of femoral head by sponging miR-127-5p through PTEN/AKT signal pathway: Experimental studies

PURPOSE

large doses of glucocorticoids (GCs) are the most common cause of glucocorticoid-induced osteonecrosis of femoral head (GIONFH). Although awareness of GIONFH among patients with GCs history has increased over recent years, several studies indicate that its mechanism remains unclear.

METHODS

To evaluate the function of circUSP45 in GIONFH, femoral heads in GIONFH patients or femoral heads in fracture patients were collected. In vitro, RT-PCR, FISH, RNA pull down and Western blotting assay were used to evaluate the function of circUSP45. In addition, we also verified the effects of circUSP45 on osteogenesis using alizarin red staining. In vivo, we used HE staining and microCT analysis to evaluate the bone mass. Moreover, the mechanism of circUSP45 regulating osteogenesis through the miR-127-5p/PTEN/AKT pathway was also investigated.

RESULTS

The results showed that expression of circUSP45 increased in GIONFH patients. The overexpression of circUSP45 decreases osteogenic gene expression and inhibits the proliferation of BMSCs. Furthermore, circUSP45 was located mainly in the cytoplasm and directly interacted with miR-127-5p. MiR-127-5p acts with its targets PTEN to regulate the osteogenesis. MicroCT and HE staining verify the function of circUSP45 in GIONFH rat model.

CONCLUSION

CircUSP45 decreases osteogenesis in bone GIONFH by sponging miR-127-5p through PTEN/AKT signal pathway.