MicroRNAs expression and their regulatory networks during mesenchymal stem cells differentiation toward osteoblasts

Establishing the Callus-Based Isolation of Extracellular Vesicles from Cissus quadrangularis and Elucidating Their Role in Osteogenic Differentiation

Extracellular vesicles (EVs) are nano-sized vehicles secreted by all live cells to establish communication with adjacent cells. In recent years, mammalian EVs (MEVs) have been widely investigated for their therapeutic implications in human disease conditions. As the understanding of MEV composition and nature is advancing, scientists are constantly exploring alternatives for EV production with similar therapeutic potential. Plant-derived exosome-like nanovesicles (PDEVs) may be a better substitute for MEVs because of their widespread sources, cost-effectiveness, and ease of access. Cissus quadrangularis (CQ), known as "bone setter or Hadjod", is a perennial plant utilized for its osteogenic potential. Its crude powder extract formulations are widely used as tablets and syrups. The present work elucidates the isolation of exosome-like nanovesicles (henceforth exosomes) from the culture supernatants of an in vitro cultured callus tissue derived from CQ. The physical and biological properties of the exosomes were successfully investigated using different characterization techniques. The therapeutic potential of the CQ exosomes was found to ameliorate the wound scratch injury and oxidative stress conditions in human-derived mesenchymal stem cells (hMSCs) and the pre-osteoblast (MC3T3) cell line. These exosomes also induced the proliferation and differentiation of hMSCs, as observed by alkaline phosphatase activity. These findings may serve as a proof of concept for further investigating the CQ exosomes as a nanocarrier for drug molecules in various therapeutic bone applications.

miR-210-3p suppresses osteogenic differentiation of MC3T3-E1 by targeting brain derived neurotrophic factor (BDNF)

Background and objective

As an important mediator of intercellular interaction and formation of extracellular bone matrix, porous scaffolds are widely used for bone regeneration. Accumulating evidences demonstrate that microRNA are involved in the regulation of scaffolds-induced bone regeneration. Recently, we revealed that miR-210-3p was highly expressed during osteogenesis induced by HAG. In present study, we further explored the molecular mechanism underlying the effect of miR-210-3p on osteogenic differentiation.

Materials and methods

In this study, miR-210-3p mimics and inhibitors were synthesized and transfected into MC3T3-E1 cells to explore their effects on osteogenic differentiation. The expression of osteogenic marker (Alp and Runx2) were detected by real-time quantitative PCR (qRT-PCR) and western blotting. After osteogenesis induction for 7 days, Alp staining were used to detected osteoblast differentiation of MC3T3-E1 cells. CCK8 and Transwell assays were performed to detected cell proliferation and migration. Then, top ranking list of target genes of miR-210-3p obtained from TargetScan and the expression of BDNF were detected by qRT-PCR and ELISA. The relationship between miR-210-3p and BDNF was verified by luciferase report assay. Furthermore,

the effect of BDNF on osteoblast differentiation was verified by transfecting siRNA or adding BDNF to the culture medium.

Results

MiR-210-3p mimics markedly suppress osteogenic differentiation, cell migration and cell proliferation of MC3T3-E; nevertheless, silencing of miR-210-3p dramatically enhanced MC3T3-E1 osteogenesis, cell migration and proliferation. Furthermore, luciferase reporter assay verified that brain derived neurotrophic factor (BDNF) is a directly target of miR-210-3p. Moreover, BDNF siRNA significantly decreased the expression levels of ALP and cell migration. The addition of BDNF partially rescued the inhibition of osteogenesis by miR-210-3p.

Conclusion

miR-210-3p inhibited the osteogenic differentiation via targeting BDNF. Our Results provide a promising target for regulating osteogenic differentiation.

Overexpression Effects of miR-424 and BMP2 on the Osteogenesis of Wharton's Jelly-Derived Stem Cells

Recently, the translational application of noncoding RNAs is accelerated dramatically. In this regard, discovering therapeutic roles of microRNAs by developing synthetic RNA and vector-based RNA is attracting attention. Here, we studied the effect of BMP2 and miR-424 on the osteogenesis of Wharton's jelly-derived stem cells (WJSCs). For this purpose, human BMP2 and miR-424 DNA codes were cloned in the third generation of lentiviral vectors and then used for HEK-293T cell transfection. Lentiviral plasmids contained miR424, BMP-2, miR424-BMP2, green fluorescent protein (GFP) genes, and helper vectors. The recombinant lentiviral particles transduced the WJSCs, and the osteogenesis was evaluated by real-time PCR, Western blot, Alizarin Red staining, and alkaline phosphatase enzyme activity. According to the results, there was a significant increase in the expression of the BMP2 gene and secretion of Osteocalcin protein in the group of miR424-BMP2. Moreover, the amount of dye deposition in Alizarin Red staining and alkaline phosphatase activity was significantly higher in the mentioned group (p < 0.05). Thus, the current study results clarify the efficacy of gene therapy by miR424-BMP2 vectors for bone tissue engineering. These data could help guide the development of gene therapy-based protocols for bone tissue engineering.

PWAR6 interacts with miR‑106a‑5p to regulate the osteogenic differentiation of human periodontal ligament stem cells

Human periodontal ligament stem cells (hPDLSCs) associated with bone regeneration serve an important role in the treatment of periodontal disease. Long non-coding RNAs are involved in the osteogenesis of multiple stem cells and can act as a sponge of microRNAs (miRs). The present study aimed to investigate the interaction between Prader Willi/Angelman region RNA 6 (PWAR6) and miR-106a-5p, as well as their influences on the osteogenic differentiation of hPDLSCs. hPDLSCs were isolated and cultured in osteogenic medium (OM) or growth medium (GM) for 7 days prior to transfection with PWAR6 overexpression vector, short hairpin RNA PWAR6 or miR-106a-5p mimic. The expression levels of runt-related transcription factor 2, osteocalcin and bone morphogenetic protein 2 (BMP2) were detected by western blotting and reverse transcription-quantitative PCR (RT-qPCR), and the expression levels of PWAR6, miR-106a-5p and alkaline phosphatase (ALP) were determined by RT-qPCR. ALP activity assays and Alizarin red staining were performed to detect osteogenesis and mineralization, respectively. Luciferase activities of wild-type and mutant PWAR6 and BMP2 were assessed by conducting a dual-luciferase reporter assay. The results indicated that PWAR6 expression was upregulated in OM-incubated hPDLSCs compared with GM-incubated hPDLSCs, and PWAR6 overexpression increased the osteogenic differentiation and mineralization of hPDLSCs compared with the corresponding control group. By contrast, miR-106a-5p expression was downregulated in OM-incubated hPDLSCs compared with GM-incubated hPDLSCs. PWAR6 acted as a sponge of miR-106a-5p and PWAR6 overexpression promoted the osteogenesis of miR-106a-5p mimic-transfected hPDLSCs. BMP2 was predicted as a target gene of miR-106a-5p. Collectively, the results indicated that PWAR6 displayed a positive influence on the osteogenic differentiation of hPDLSCs. The results of the present study demonstrated that the PWAR6/miR-106a-5p interaction network may serve as a potential regulatory mechanism underlying hPDLSCs osteogenesis.

Effects of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells on microRNA Expressions in Acute Alkaline Corneal Burn

Purpose: The aim of this study was to investigate the microRNA (miRNA) expressions of the corneal tissue after an alkaline burn and to compare the efficiency of adipose- and bone marrow-derived mesenchymal stem cells (MSCs) on expressions. Methods: Thirty-two rats were divided into 4 groups. No intervention was made in the control group. A chemical burn was created by applying 4 μL NaOH soaked in 6 mm filter paper to the right eye of each animal in the other groups. Whereas only subconjunctival 0.1 mL phosphate-buffered saline (PBS) was injected to in the group 1, 2 × 10⁶ adipose- or bone marrow-derived MSC in 0.1 mL PBS was injected subconjunctivally to the animals in the remaining groups (groups 2 and 3, respectively). Tissue samples were collected for miRNA analysis on the third day after the burn. Results: When group 1 was compared with the control group, the expression of 3 of 93 miRNAs increased significantly, whereas the expression of 50 miRNAs decreased significantly. Significant changes in miRNA expressions were observed when group 1 was compared with groups 2 and 3. Although a significant change was observed in the expression of 6 miRNAs in the adipose-derived MSC group, it was found that the expression of 65 miRNAs significantly changed in the bone marrow-derived MSC group. Conclusion: This study shows that there are significant changes in some miRNA expressions after corneal alkaline burn and these changes can be reversed with the subconjunctival injection of MSCs.

MiR-130a in the adipogenesis of human SGBS preadipocytes and its susceptibility to androgen regulation

Objectives: Adipogenesis is the differentiation process generating mature adipocytes from undifferentiated mesenchymal stem cells. The differentiation can be inhibited by androgens, although knowledge about intracellular effectors of this inhibition is scarce. Recently, androgen-regulated microRNAs were detected as interesting candidates in this context. In this study, we analyse the role of miR-130a and miR-301 in the adipogenesis of human SGBS preadipocytes and whether they are prone to androgen regulation. Materials and Methods: microRNA expression during adipogenic differentiation with or without androgen stimulation was measured by qPCR. Putative target genes of miR-130a and miR-301 were identified by target database search and validated in luciferase reporter assays. Results: miR-130a and miR-301 are both significantly downregulated on day 3 and day 5 of adipogenic differentiation in comparison to day 0. Under androgen stimulation, a significant upregulation of miR-130a was detected after 7 days of adipogenesis lasting to day 14, while miR-301 did not change significantly until day 14. Luciferase reporter assays revealed the androgen receptor (AR), adiponectin (ADIPOQ) and tumour necrosis factor alpha (TNFα) as miR-130a target genes. Conclusions: miR-130a is an androgen-regulated microRNA that is downregulated during the early phase of adipogenesis and exerts its functions by regulating AR and ADIPOQ translation. These data may help to identify new signalling pathways associated with the androgen-mediated inhibition of adipogenesis.

Ortho-silicic acid enhances osteogenesis of osteoblasts through the upregulation of miR-130b which directly targets PTEN

AIMS

Osteoporosis is considered a common skeletal disease. Ortho-silicic acid has been found to enhance the osteogenic differentiation of osteoblasts. However, the molecular mechanism of osteogenesis induced by ortho-silicic acid is still undefined totally. MicroRNAs (miRs) play a key role in osteogenesis of osteoblasts. This study investigated the role of miR-130b in promoting osteogenesis induced by ortho-silicic acid.

MAIN METHODS AND KEY FINDINGS

In this study, we found ortho-silicic acid enhanced osteogenesis of osteoblasts in vitro and promoted preventing and treating osteoporosis in vivo. Furthermore, the expression of miR-130b increased under application of ortho-silicic acid. In vitro, experiments demonstrated miR-130b overexpression or inhibition significantly promoted or suppressed osteogenic differentiation of osteoblasts under application of ortho-silicic acid, respectively. Consistently, downregulation of miR-130b in ovariectomy (OVX) rats dropped off the beneficial effect of ortho-silicic acid against bone loss. Mechanistically, we identified phosphatase and tensin homologue deleted on human chromosome 10 (PTEN) as the direct target of miR-130b during osteogenesis induced by ortho-silicic acid.

SIGNIFICANCE

In conclusion, our findings reveal that ortho-silicic acid promotes the osteogenesis of osteoblasts mediated by the miR-130b/PTEN signaling axis, which identifies a new target to prevent and treat osteoporosis.

Decreased expression of miR-24 in peripheral plasma of type 2 diabetes mellitus patients associated with diabetic foot ulcer

To examine the correlations of miR-24 expression in peripheral plasma with the onset of diabetic foot ulcer (DFU) and diabetic foot osteomyelitis (DFO) in type 2 diabetes mellitus (T2DM) patients and explore the clinical value of miR-24 as a potential biomarker for the diagnosis and treatment outcomes of DFU and DFO, a total of 60 newly diagnosed T2DM patients without DFU (T2DM group), 112 T2DM patients with DFU (DFU group), and 60 healthy controls (NC group) were included. DFU group were further divided into DFO group (n = 64) and non-DFO group (n = 48). MiR-24 levels were determined by quantitative real-time PCR, while clinical features and risk factors of DFU and DFO were explored. The expression level of miR-24 in T2DM and DFU group was significantly lower than in NC group (P < .05), and that in DFU group was significantly lower than in T2DM group (P < .01). Additionally, the level of miR-24 significantly decreased in DFO group compared to non-DFO group (P < .01). Moreover, it was negatively correlated with the amputation rate in DFU group (P = .043) and positively correlated with healing rate after 8 weeks (P = .036). The multivariate logistic regression analysis confirmed that a low expression of miR-24 was an independent risk factor for DFU and DFO. The ROC curve analysis indicated that the AUC of miR-24 for the diagnosis of DFU and DFO was 0.849 (95% CI, 0.618-0.879, P < .001) and 0.782 (95% CI, 0.595-0.813, P < .001). Thus, a decreased expression of miR-24 of T2DM patients was closely related to the occurrence, development and prognosis of DFU and DFO, suggesting the use of miR-24 as a potential biomarker for the prediction of DFU and DFO.

An osteoinductive effect of phytol on mouse mesenchymal stem cells (C3H10T1/2) towards osteoblasts

In recent years, phytochemicals have been widely researched and utilized for the treatment of various medical conditions such as cancer, cardiovascular diseases, age-related problems and are also said to have bone regenerative effects. In this study, phytol (3,7,11,15-tetramethylhexadec-2-en-1-ol), an acyclic unsaturated diterpene alcohol and a secondary metabolite derived from aromatic plants was investigated for its effect on osteogenesis. Phytol was found to be nontoxic in mouse mesenchymal stem cells (C3H10T1/2). At the cellular level, phytol-treatment promoted osteoblast differentiation, as seen by the increased calcium deposits. At the molecular level, phytol-treatment stimulated the expression of Runx2 (a bone-related transcription factor) and other osteogenic marker genes. MicroRNAs (miRNAs) play an essential role in controlling bone metabolism by targeting genes at the post-transcriptional level. Upon phytol-treatment in C3H10T1/2 cells, mir-21a and Smad7 levels were increased and decreased, respectively. It was previously reported that mir-21a targets Smad7 (an antagonist of TGF-beta1 signaling) and thus, protects Runx2 from its degradation. Thus, based on our results, we suggest that phytol-treatment promoted osteoblast differentiation in C3H10T1/2 cells via Runx2 due to downregulation of Smad7 by mir-21a. Henceforth, phytol was identified to bolster osteoblast differentiation, which in turn may be used for bone regeneration.

Pterostilbene Attenuates Fructose-Induced Myocardial Fibrosis by Inhibiting ROS-Driven Pitx2c/miR-15b Pathway

Excessive fructose consumption induces oxidative stress and myocardial fibrosis. Antioxidant compound pterostilbene has cardioprotective effect in experimental animals. This study is aimed at investigating how fructose drove fibrotic responses via oxidative stress in cardiomyocytes and explored the attenuation mechanisms of pterostilbene. We observed fructose-induced myocardial hypertrophy and fibrosis with ROS overproduction in rats. Paired-like homeodomain 2 (Pitx2c) increase, microRNA-15b (miR-15b) low expression, and p53 phosphorylation (p-p53) upregulation, as well as activation of transforming growth factor-β1 (TGF-β1)/drosophila mothers against DPP homolog (Smads) signaling and connective tissue growth factor (CTGF) induction, were also detected in fructose-fed rat hearts and fructose-exposed rat myocardial cell line H9c2 cells. The results from p53 siRNA or TGF-β1 siRNA transfection showed that TGF-β1-induced upregulation of CTGF expression and p-p53 activated TGF-β1/Smads signaling in fructose-exposed H9c2 cells. Of note, Pitx2c negatively modulated miR-15b expression via binding to the upstream of the miR-15b genetic loci by chromatin immunoprecipitation and transfection analysis with pEX1-Pitx2c plasmid and Pitx2c siRNA, respectively. In H9c2 cells pretreated with ROS scavenger N-acetylcysteine, or transfected with miR-15b mimic and inhibitor, fructose-induced cardiac ROS overload could drive Pitx2c-mediated miR-15b low expression, then cause p-p53-activated TGF-β1/Smads signaling and CTGF induction in myocardial fibrosis. We also found that pterostilbene significantly improved myocardial hypertrophy and fibrosis in fructose-fed rats and fructose-exposed H9c2 cells. Pterostilbene reduced cardiac ROS to block Pitx2c-mediated miR-15b low expression and p-p53-dependent TGF-β1/Smads signaling activation and CTGF induction in high fructose-induced myocardial fibrosis. These results firstly demonstrated that the ROS-driven Pitx2c/miR-15b pathway was required for p-p53-dependent TGF-β1/Smads signaling activation in fructose-induced myocardial fibrosis. Pterostilbene protected against high fructose-induced myocardial fibrosis through the inhibition of Pitx2c/miR-15b pathway to suppress p-p53-activated TGF-β1/Smads signaling, warranting the consideration of Pitx2c/miR-15b pathway as a therapeutic target in myocardial fibrosis.

Differential miRNAs profile and bioinformatics analyses in bone marrow mesenchymal stem cells from adolescent idiopathic scoliosis patients

BACKGROUND CONTEXT

Coexistence of abnormal skeletal growth and reduced bone mineral density in the context of adolescent idiopathic scoliosis (AIS) suggests disturbed bone metabolism existing in such patients. Our previous study suggested increased proliferation ability and decreased osteogenic differentiation ability of bone marrow mesenchymal stem cells (BM-MSCs) of AIS.

PURPOSE

To explore the differential miRNA expression profile, Go (gene ontology) terms and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways in BM-MSCs of AIS and non-AIS controls were conducted using microarray approach and bioinformatics analyses.

STUDY DESIGN

miRNA microarray approach and bioinformatics analysis.

METHODS

The differentially expressed miRNAs (DEMs) of BM-MSCs from AIS patients compared with those from healthy individuals were analyzed using a microarray analysis. Comprehensive bioinformatics analyses were then used to enrich datasets for gene ontology and pathway. Based on the interaction network analysis of DEMs contained in significant pathways, 12 potential crucial miRNAs were selected for validation by RT-PCR.

RESULTS

The study identified 54 previously unrecognized DEMs (12 upregulated, 42 downregulated) in BM-MSCs from AIS patients. These miRNAs are involved in multiple biological processes, including small GTPase-mediated signal transduction, DNA-dependent transcription, cytokinesis, cell adhesion, transmembrane transport, response to hypoxia, etc. Pathway analysis of these new identified miRNAs revealed dysregulated MAPK signaling pathway, PI3K-Akt signaling pathway, calcium signaling pathway, Notch signaling pathway, and ubiquitin-mediated proteolysis pathway, all of which have been reported to play important role in regulating the osteogenic or adipogenic differentiation of MSCs. Furthermore, interaction networks analysis indicated that seven most significant central miRNAs, including miR-17-5p, miR-106a-5p, miR-106b-5p, miR-16-5p, miR-93-5p, miR-15a-5p, and miR-181b-5p may play essential roles in AIS pathogenesis and accompanied osteopenia.

CONCLUSION

The current study reports the differential miRNAs expression profiles of BM-MSCs from AIS patients and related pathways for the first time. The identification of these candidate miRNAs provides a deep insight into the pathogenesis of AIS and the accompanying generalized osteopenia.

Tanshinone IIA exerts beneficial effects on fracture healing in vitro and in vivo

BACKGROUND

Fracture healing is a very important process after fracture. Tanshinone IIA (Tan IIA) has been reported to possess beneficial impact on osteoblasts growth. Our study investigated the effects of Tan IIA on fracture healing.

METHODS

In vitro, mouse pre-osteoblast MC3T3-E1 cells were treated with Tan IIA. Then, the protein levels of Runx2, Osx, Collagen I, JNK and c-Jun, alkaline phosphatase (ALP) activity and calcium deposition were detected, respectively. Furthermore, the roles of microRNA-424 (miR-424) and Bone morphogenetic protein 2 (BMP-2) in Tan IIA-caused MC3T3-E1 cell differentiation were probed. In vivo, mice open osteotomy at femur diaphysis model was established. The callus area, callus intensity, low-density bone volume/callus total volume (BV1/TV), tissue mineral density (TMD) and bone mineral density (BMD) were tested.

RESULTS

In vitro, Tan IIA promoted MC3T3-E1 cell differentiation via increasing the Runx2, Osx and collagen I expression, along with enhancing ALP activity and calcium deposition. In addition, Tan IIA activated JNK pathway in MC3T3-E1 cells, while inhibition of JNK pathway mitigated the Tan IIA-caused MC3T3-E1 cell differentiation. Moreover, Tan IIA declined the miR-424 expression in MC3T3-E1 cells. Overexpression of miR-424 also weakened the Tan IIA-caused MC3T3-E1 cell differentiation. BMP-2 was a target gene of miR-424. BMP-2 silence reversed the Tan IIA-caused activation of JNK pathway. In vivo, Tan IIA increased the callus area, callus intensity, BV1/TV, TMD and BMD.

CONCLUSION

Tan IIA could promote fracture healing. In vitro, Tan IIA promoted MC3T3-E1 cell differentiation might be via down-regulating miR-424, up-regulating BMP-2 and then activating JNK pathway.

Osteogenic potential of zingerone, a phenolic compound in mouse mesenchymal stem cells

Zingerone, 4-(4-hydroxy-3-methoxyphenyl)-2-butanone (Zg), a phenolic compound isolated from ginger is reported to have anti-inflammatory and antidiabetic properties. However, its role in the promotion of osteogenesis is not known. In this study, we investigated the therapeutic effect of Zg on osteogenesis at the cellular and molecular levels. Zg treatment was nontoxic to mouse mesenchymal stem cells (mMSCs). At the cellular level, it enhanced osteoblast differentiation as evidenced by more calcium deposits. At the molecular level, Zg stimulated the expression of Runx2 (a bone transcription factor) and other marker genes of osteoblast differentiation in mMSCs. Recent studies indicated that microRNAs (miRNAs) regulate bone metabolism, and we identified that Zg treatment in mMSCs upregulated mir-590, a positive regulator of Runx2 by targeting Smad7, an antagonist of TGF-β1 signaling. Thus, the osteogenic potential of Zg would be beneficial for treating bone and bone-related diseases.

Deregulated miRNAs in bone health: Epigenetic roles in osteoporosis

MicroRNA (miRNA) has shown to enhance or inhibit cell proliferation, differentiation and activity of different cell types in bone tissue. The discovery of miRNA actions and their targets has helped to identify them as novel regulations actors in bone. Various studies have shown that miRNA deregulation mediates the progression of bone-related pathologies, such as osteoporosis. The present review intends to give an exhaustive overview of miRNAs with experimentally validated targets involved in bone homeostasis and highlight their possible role in osteoporosis development. Moreover, the review analyzes miRNAs identified in clinical trials and involved in osteoporosis.

High Glucose-Induced Apoptosis in Human Kidney Cells Was Alleviated by miR-15b-5p Mimics

MicroRNAs were involved in a wide range of biological processes of diabetic nephropathy (DN). It is reported that miR-15b-5p was downregulated in the patients with DN. However, the mechanisms underlying the regulatory effects of miR-15b-5p on patients with diabetes remain unclear. Thus, this study aimed to investigate the role of miR-15b-5p during high glucose (HG)-induced apoptosis in human kidney cells. Quantitative real-time (qRT)-PCR was used to detect the level of miR-15b-5p. CCK-8 assay, EdU staining assays and flow cytometry were used to detect cell proliferation, apoptosis respectively in vitro. In addition, Western blotting was used to determine active caspase-3, cleaved poly(ADP-ribose) polymerase (PARP), phosphorylated (p)-AKT, p-mammalian target of rapamycin (mTOR), p-S6, p-c-Jun N terminal kinase (JNK), p-p38 and p-extracellular signal-regulated kinase (ERK) proteins levels. The expression of miR-15b-5p in patients with DN were dramatically decreased compared with health persons. Similarly, HG down-regulated the expression of miR-15b-5p in HK-2 cells. In contrast, miR-15b-5p mimics alleviated HG-induced apoptosis in HK-2 cells via decreasing the expressions of active caspase 3 and cleaved PARP. EdU detection further confirmed that miR-15b-5p mimics attenuated the anti-proliferation effect of HG in HK-2 cells. Furthermore, HG-induced Akt/mTOR pathway downregulation and JNK upregulation were markedly reversed by miR-15b-5p mimics in cells. The data suggested that miR-15b-5p mimics protects HK-2 cells from HG-induced apoptosis. The anti-apoptotic effects of miR-15b-5p may due to the activation of the Akt/mTOR pathway as well as inactivation of JNK. Taken together, miR-15b-5p might be a potential therapeutic target for the treatment of patients with DN.

Micrornas at the Interface between Osteogenesis and Angiogenesis as Targets for Bone Regeneration

Bone formation and regeneration is a multistep complex process crucially determined by the formation of blood vessels in the growth plate region. This is preceded by the expression of growth factors, notably the vascular endothelial growth factor (VEGF), secreted by osteogenic cells, as well as the corresponding response of endothelial cells, although the exact mechanisms remain to be clarified. Thereby, coordinated coupling between osteogenesis and angiogenesis is initiated and sustained. The precise interplay of these two fundamental processes is crucial during times of rapid bone growth or fracture repair in adults. Deviations in this balance might lead to pathologic conditions such as osteoarthritis and ectopic bone formation. Besides VEGF, the recently discovered important regulatory and modifying functions of microRNAs also support this key mechanism. These comprise two principal categories of microRNAs that were identified with specific functions in bone formation (osteomiRs) and/or angiogenesis (angiomiRs). However, as hypoxia is a major driving force behind bone angiogenesis, a third group involved in this process is represented by hypoxia-inducible microRNAs (hypoxamiRs). This review was focused on the identification of microRNAs that were found to have an active role in osteogenesis as well as angiogenesis to date that were termed "CouplingmiRs (CPLGmiRs)". Outlined representatives therefore represent microRNAs that already have been associated with an active role in osteogenic-angiogenic coupling or are presumed to have its potential. Elucidation of the molecular mechanisms governing bone angiogenesis are of great relevance for improving therapeutic options in bone regeneration, tissue-engineering, and the treatment of bone-related diseases.

miR-125b-5p and miR-99a-5p downregulate human γδ T-cell activation and cytotoxicity

As an important component of innate immunity, human circulating γδ T cells function in rapid responses to infections and tumorigenesis. MicroRNAs (miRNAs) play a critical regulatory role in multiple biological processes and diseases. Therefore, how the functions of circulating human γδ T cells are regulated by miRNAs merits investigation. In this study, we profiled the miRNA expression patterns in human peripheral γδ T cells from 21 healthy donors and identified 14 miRNAs that were differentially expressed between peripheral αβ T cells and γδ T cells. Of the 14 identified genes, 7 miRNAs were downregulated, including miR-150-5p, miR-450a-5p, miR-193b-3p, miR-365a-3p, miR-31-5p, miR-125b-5p and miR-99a-5p, whereas the other 7 miRNAs were upregulated, including miR-34a-5p, miR-16-5p, miR-15b-5p, miR-24-3p, miR-22-3p, miR-22-5p and miR-9-5p, in γδ T cells compared with αβ T cells. In subsequent functional studies, we found that both miR-125b-5p and miR-99a-5p downregulated γδ T cell activation and cytotoxicity to tumor cells. Overexpression of miR-125b-5p or miR-99a-5p in γδ T cells inhibited γδ T cell activation and promoted γδ T cell apoptosis. Additionally, miR-125b-5p knockdown facilitated the cytotoxicity of γδ T cells toward tumor cells in vitro by increasing degranulation and secretion of IFN-γ and TNF-α. Our findings improve the understanding of the regulatory functions of miRNAs in γδ T cell activation and cytotoxicity, which has implications for interventional approaches to γδ T cell-mediated cancer therapy.

Nitric oxide regulates intussusceptive-like angiogenesis in wound repair in chicken embryo and transgenic zebrafish models

Angiogenesis is the formation of new blood vessels that occurs by two distinct processes following sprouting angiogenesis (SA) and intussusceptive angiogenesis (IA). Nitric oxide (NO) is known for its pro-angiogenic functions. However, no clear mechanisms are delineated on its role in promoting angiogenesis in reparative wound healing. We propose that NO regulates SA to IA transition and vice versa in wound milieu. We have used three models which include a new chick embryo extra-vasculature (CEV) burn wound model, adult Tie2-GFP transgenic Zebrafish caudal fin regeneration model and Zebrafish skin wound model to study the mechanisms underlying behind the role of NO in wound healing. Wounds created in CEV were treated with NO donor (Spermine NONOate (SPNO)), NOS inhibitor (L-nitro-l-arginine-methyl ester (l-NAME)), NaNO₂, NaNO₃, and beetroot juice, a nitrite-rich juice respectively and the pattern of wound healing was assessed. Morphological and histological techniques tracked the wound healing at the cellular level, and the molecular changes were investigated by using real-time RT-PCR gene expression analysis. The result concludes that NO donor promotes wound healing by activating SA at an early phase of healing while NOS inhibitor induces wound healing via IA. At the later phase of wound healing NO donor followed IA while NOS inhibitor failed to promote wound repair. The current work underpinned a differential regulation of NO on angiogenesis in wound milieu and this study would provide new insights in designing therapeutics for promoting wound repair.

Syringic acid, a phenolic acid, promotes osteoblast differentiation by stimulation of Runx2 expression and targeting of Smad7 by miR-21 in mouse mesenchymal stem cells

Syringic acid (SA), a phenolic acid, has been used in Chinese and Indian medicine for treating diabetes but its role in osteogenesis has not yet been investigated. In the present study, at the molecular and cellular levels, we evaluated the effects of SA on osteoblast differentiation. At the cellular level, there was increased alkaline phosphatase (ALP) activity and calcium deposition by SA treatment in mouse mesenchymal stem cells (mMSCs). At the molecular level, SA treatment of these cells stimulated expression of Runx2, a bone transcription factor, and of osteoblast differentiation marker genes such as ALP, type I collagen, and osteocalcin. It is known that Smad7 is an antagonist of TGF-β/Smad signaling and is a negative regulator of Runx2. microRNAs (miRNAs) play a key role in the regulation of osteogenesis genes at the post-transcriptional level and studies have reported that Smad7 is one of the target genes of miR-21. We found that there was down regulation of Smad7 and up regulation of miR-21 in SA-treated mMSCs. We further identified that the 3'-untranslated region (UTR) of Smad7 was directly targeted by miR-21 in these cells. Thus, our results suggested that SA promotes osteoblast differentiation via increased expression of Runx2 by miR-21-mediated down regulation of Smad7. Hence, SA may have potential in orthopedic applications.

Nanotopographical cues of electrospun PLLA efficiently modulate non-coding RNA network to osteogenic differentiation of mesenchymal stem cells during BMP signaling pathway

Application of stem cells in combination with nanofibrous substrates is an interesting biomimetic approach for enhanced regeneration of damaged tissues such as bone and cartilage. The investigation of the complex interplay between nanotopographical cues of niche and noncoding RNAs in stem cells fate is an effective tool to find a new strategy for enhancing the induction of osteogenesis. In this study, we investigated the effects of aligned and random orientations of nanofibers as a natural ECM-mimicking environment on the network of noncoding RNA in mesenchymal stem cells. Aligned and randomly oriented Ploy (L-lactide) PLLA scaffolds were fabricated via electrospinning. Human Adipose Tissue-Derived Mesenchymal Stem Cells (hASCs) were isolated from adipose tissue and were cultured on surfaces of these scaffolds. Their capacity to support hMSCs proliferation was also investigated by MTT assay and the expression of c-Myc gene. Then, after 7, 14 and 21 days, the osteogenic commitment of hMSCs and the miRNA regulatory network in BMP signaling pathway were evaluated by measuring alkaline phosphatase (ALP) activity, extracellular calcium deposition, and bone-related gene activation by Real-Time PCR. Furthermore, osteogenic differentiation was evaluated with regard to their noncoding RNA network. Our results for the first time showed an interaction between nanotopographical cues and miRNA activity in hMSCs. We found that the nanotopographical cues could be used to influence the osteogenic differentiation process of hMSCs through the modulation of lncRNAs and miR-125b as negative regulators of osteogenesis as well as the H19 modulator BMP signaling pathway that acts as a miRNA sponge. Moreover, we also demonstrated for the first time that MEG3 as a long noncoding RNA is controlled by miR-125b and microRNA-triggered lncRNA decay mechanism. This strategy seems to be an important tool for controlling stem cell fate in engineered tissues and provide new insights into most biocompatible scaffolds for bone-graft substitutes.

Biogenic gold nanoparticles synthesis mediated by Mangifera indica seed aqueous extracts exhibits antibacterial, anticancer and anti-angiogenic properties

During the last few decades, gold nanoparticles (AuNP's) have gained considerable attention in nanomedicine and expanded its application in clinical diagnosis and as therapeutics. Employing plant extract for synthesising gold nanoparticles proves to be an eco-friendly technology for large scale production. It is highly economical and suitable for biological applications by negating the use of chemicals involved in conventional route. In this study, AuNP's was prepared by a simple one step method of employing aqueous Mangifera indica seed extract as a reducing agent. Scanning electron microscopy and transmission electron microscopy revealed spherical shaped nanoparticles and dynamic light scattering analysis indicated the AuNP's to be approximately 46.8 nm in size. AuNP's efficiently inhibited the growth of E. coli and S. aureus by its inherent ability to generate reactive oxygen species (ROS) and exhibited detrimental effects towards the tested bacterial species. Biocompatibility assessment indicated the non-toxic nature of AuNP's towards mesenchymal stem cells at 25 μg/ml and interestingly, suppressed the growth of human gastric cancer cells under in vitro culture conditions. AuNP's significantly exhibited anti-angiogenic property in chick chorioallantoic membrane model (CAM) by downregulating Ang-1/Tie2 pathway. Overall, the synthesized AuNP's exhibited antibacterial and anti-angiogenic properties with high biocompatibility thereby supporting its candidature for various biomedical applications. It can be employed in suppressing tumor growth, combat inflammatory diseases that necessitate the involvement of angiogenesis suppression, and antibacterial activity is suitable for its clinical translation to negate surgery associated infections.

miR-27b-3p Suppressed Osteogenic Differentiation of Maxillary Sinus Membrane Stem Cells by Targeting Sp7

OBJECTIVE

To explore the critical role and function of miRNAs in the regulation of development and physiology of maxillary sinus membrane stem cell (MSMSC) osteogenesis.

METHODS

Microarray analysis was performed to screen the miRNAs expression profiles during the process of MSMSC osteogenic differentiation. Quantitative real-time polymerase chain reaction was applied to verify the miRNAs expression profiles. Gain- and loss-of-function experiments were used to demonstrate that miR-27b-3p inhibited MSMSC osteoblastic differentiation. Bioinformatic analysis was performed to predict the potential target of miR-27b-3p and then demonstrated by luciferase reporter assay and western blot. The negative regulation between miR-27b-3p and Sp7 was further confirmed using mimic and inhibitor of miR-27b-3p in vitro. Xenograft mice model was generated to confirm the relationship between miR-27b-3p and Sp7 using recombinant adenoviruses in vivo.

RESULTS

MiR-27b-3p was downregulated during osteogenic differentiation of MSMSCs. The expression of Sp7, alkaline phosphatase, and osteocalcin decreased when transfected with miR-27b-3p-mimic in MSMSCs after osteogenic differentiation. MiR-27b-3p directly targeted Sp7 and inhibited the MSMSC osteogenesis in vivo.

CONCLUSION

MiR-27b-3p suppressed the osteogenic differentiation of MSMSCs by directly inhibiting Sp7.

Nitric oxide signaling regulates tumor-induced intussusceptive-like angiogenesis

Existing animal models for screening tumor angiogenic process have various setbacks that necessitate further investigations. In this study, we developed an ex-ovo egg yolk angiogenesis model to screen the angiogenic potency of tumor cells (HeLa and SiHa cell lines). The egg yolk angiogenesis assay was applied to study the nitric oxide (NO) influence on switching from sprouting angiogenesis (SA) to intussusceptive angiogenesis (IA) under tumor microenvironment. Morphological analysis and SA-like or IA-like markers expression were determined during the development of chicken chorioallantoic membrane (CAM) from day 5 to 13. Expression of Notch1, Notch2, EphrinB2, and Tie2 were considered as SA-like while TEM8, CALD1, CXCR4 and HOMX1 were followed as IA-like markers. The HeLa and SiHa cell lines embedded CAM showed an increase in micro and macro blood vessels and vascular size, junction and length which are the pivotal morphological parameters of angiogenesis. Further, the study revealed that HeLa is more aggressive than SiHa in inducing tumor angiogenesis. To determine the NO signaling implication in tumor milieu, NO donor (Spermine NONOate (SPNO)), NOS inhibitor (L-nitro-L-arginine-methyl ester (L-NAME) and VEGF inhibitor (Avastin) were administrated to chick embryo vascular bed with and without HeLa cells. The results demonstrated that HeLa cells promote IA through NO signaling, VEGF and eNOS and it was documented by angiogenic morphological parameters and SA-like or IA-like markers expression. Therefore, our study claims that ex-ovo egg yolk angiogenesis model could be used to study tumor angiogenesis and NO plays a key role in switching of IA under tumor microenvironment.

Chitosan/nano-hydroxyapatite/nano-zirconium dioxide scaffolds with miR-590-5p for bone regeneration

Bone tissue engineering (BTE) relies on biocomposite scaffolds and bioactive molecules for bone regeneration. The present study was aimed to synthesize and characterize biocomposite scaffolds containing chitosan (CS), nano-hydroxyapatite (nHAp) and nano‑zirconium dioxide (nZrO₂) along with microRNA (miRNA) for BTE applications. miRNAs act as post-transcriptional regulator of gene expression. The fabricated biocomposite scaffolds were characterized using SEM, FT-IR and XRD analyses. The effect of a bioactive molecule (miR-590-5p) with scaffolds was tested for osteoblast differentiation at the cellular and molecular levels using mouse mesenchymal stem cells (C3H10T1/2). The results showed that CS/nHAp/nZrO₂ scaffolds promoted osteoblast differentiation, and this effect was further increased in the presence of miR-590-5p in C3H10T1/2 cells. Thus, we suggested that CS/nHAp/nZrO₂ scaffolds with miR-590-5p would have potential towards the treatment of bone defects.

MicroRNA-99a is a novel regulator of KDM6B-mediated osteogenic differentiation of BMSCs

Skeletal tissue originates from mesenchymal stem cells (MSCs) with differentiation potential into the osteoblast lineage regulated by essential transcriptional and post‐transcriptional mechanisms. Recently, miRNAs and histone modifications have been identified as novel key regulators of osteogenic differentiation of MSCs. Here, we identified miR‐99a and its target lysine (K)‐specific demethylase 6B (KDM6B) gene as novel modulators of osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Microarray profiling and further validation by quantitative real‐time RT‐PCR revealed that miR‐99a was up‐regulated during osteoblastic differentiation of BMSCs, and decreased in differentiated osteoblasts. Transfection of miR‐99a mimics inhibited osteoblastic commitment and differentiation of BMSCs, whereas inhibition of miR‐99a by inhibitors enhances these processes. KDM6B was determined as one of important targets of miR‐99a, which was further confirmed by luciferase assay of 3′‐UTR of KDM6B. Moreover, HOX gene level decreased after transfection of miR‐99a mimics in BMSCs, which indicated that KDM6B is a bona fide target of miR‐99a. Furthermore, in a model of in vivo bone regeneration, osteoblast‐specific gain‐ and loss‐of‐function experiments performed using cranial bone defects revealed that miR‐99a mimics‐transfected BMSCs reduced bone formation, and conversely, miR‐99a inhibitors‐transfected BMSCs increased in vivo bone formation. Tissue‐specific inhibition of miR‐99a may be a potential novel therapeutic approach for enhancing BMSCs‐based bone formation and regeneration.

Identification of novel genes in aging osteoblasts using next-generation sequencing and bioinformatics

During the aging process, impaired osteoblastic function is one key factor of imbalanced bone formation and age-related bone loss. The aim of this study is to explore the differentially expressed genes in normal and aged osteoblasts and to identify genes potentially involved in age-related alteration in bone physiology. Based on next generation sequencing and bioinformatics analysis, 12 differentially expressed microRNAs and 22 differentially expressed genes were identified. Up-regulation of miR-204-5p was validated in an array of osteoporotic hip fracture in the Gene Expression Omnibus database (GSE74209). The putative targets for miR-204-5p were Kruppel-like factor 7 (KLF7) and SRY-box 11 (SOX11). Ingenuity Pathway Analysis identified SOX11, involved in osteoarthritis pathway and differentiation of osteoblasts, together with miR-204-5p, a potential upstream regulator, suggesting the critical role of miR-204-5p-SOX11 regulation in the aging process of human bones. In addition, as semaphorin 3A (SEMA3A) and ephrin type-A receptor 5 (EPHA5) were involved in nervous system related biological functions, we postulated a potential linkage between SEMA3A, EPHA5 and development of neurogenic heterotopic ossification. Our findings implicate new candidate genes in the diagnosis of geriatric musculoskeletal disorders, and provide novel insights that may contribute to the elaboration of new biomarkers for neurogenic heterotopic ossification.

Epigenome alterations in aortic valve stenosis and its related left ventricular hypertrophy

Aortic valve stenosis is the most common cardiac valve disease, and with current trends in the population demographics, its prevalence is likely to rise, thus posing a major health and economic burden facing the worldwide societies. Over the past decade, it has become more than clear that our traditional genetic views do not sufficiently explain the well-known link between AS, proatherogenic risk factors, flow-induced mechanical forces, and disease-prone environmental influences. Recent breakthroughs in the field of epigenetics offer us a new perspective on gene regulation, which has broadened our perspective on etiology of aortic stenosis and other aortic valve diseases. Since all known epigenetic marks are potentially reversible this perspective is especially exciting given the potential for development of successful and non-invasive therapeutic intervention and reprogramming of cells at the epigenetic level even in the early stages of disease progression. This review will examine the known relationships between four major epigenetic mechanisms: DNA methylation, posttranslational histone modification, ATP-dependent chromatin remodeling, and non-coding regulatory RNAs, and initiation and progression of AS. Numerous profiling and functional studies indicate that they could contribute to endothelial dysfunctions, disease-prone activation of monocyte-macrophage and circulatory osteoprogenitor cells and activation and osteogenic transdifferentiation of aortic valve interstitial cells, thus leading to valvular inflammation, fibrosis, and calcification, and to pressure overload-induced maladaptive myocardial remodeling and left ventricular hypertrophy. This is especcialy the case for small non-coding microRNAs but was also, although in a smaller scale, convincingly demonstrated for other members of cellular epigenome landscape. Equally important, and clinically most relevant, the reported data indicate that epigenetic marks, particularly certain microRNA signatures, could represent useful non-invasive biomarkers that reflect the disease progression and patients prognosis for recovery after the valve replacement surgery.

Mixed-ligand copper(II) complex of quercetin regulate osteogenesis and angiogenesis

Copper(II) complex of quercetin Cu+Q, mixed ligand complexes, quercetin-Cu(II)-phenanthroline [Cu+Q(PHt)] and quercetin-Cu(II)-neocuproine [Cu+Q(Neo)] have been synthesized and characterized. From the FT-IR spectroscopic studies, it was evident that C-ring of quercetin is involved in the metal chelation in all the three copper complexes. C-ring chelation was further proven by UV-Visible spectra and the presence of Cu(II) from EPR spectroscopic investigations. These complexes were found to have osteogenic and angiogenic properties, observed through in vitro osteoblast differentiation and chick embryo angiogenesis assay. In osteoblast differentiation, quercetin-Cu(II) complexes treatment increased calcium deposition and alkaline phosphatase activity (ALP) activity at the cellular level and stimulated Runx2 mRNA and protein, ALP mRNA and type 1 collagen mRNA expression at the molecular level. Among the complexes, Q+Cu(PHt) showed more effects on osteoblast differentiation when compared to that of other two copper complexes. Additionally, Q+Cu(Neo) showed more effect compared to Q+Cu. Furthermore, the effect of these complexes on osteoblast differentiation was confirmed by the expression of osteoblast specific microRNA, pre-mir-15b. The chick embryo angiogenesis assay showed that angiogenic parameters such as blood vessel length, size and junctions were stimulated by these complexes. Thus, the present study demonstrated that quercetin copper(II) complexes exhibit as a pharmacological agent for the orthopedic application.

Alginate/Gelatin scaffolds incorporated with Silibinin-loaded Chitosan nanoparticles for bone formation in vitro

Silibinin is a plant derived flavonolignan known for its multiple biological properties, but its role in the promotion of bone formation has not yet been well studied. Moreover, the delivery of Silibinin is hindered by its complex hydrophobic nature, which limits its bioavailability. Hence, in this study, we fabricated a drug delivery system using chitosan nanoparticles loaded with Silibinin at different concentrations (20μM, 50μM, and 100μM). They were then incorporated into scaffolds containing Alginate and Gelatin (Alg/Gel) for the sustained and prolonged release of Silibinin. The Silibinin-loaded chitosan nanoparticles (SCN) were prepared using the ionic gelation technique, and the scaffolds (Alg/Gel-SCN) were synthesized by the conventional method of freeze drying. The scaffolds were subjected to physicochemical and material characterization studies. The addition of SCN did not affect the porosity of the scaffolds, yet increased the protein adsorption, degradation rates, and bio-mineralization. These scaffolds were biocompatible with mouse mesenchymal stem cells. The scaffolds loaded with 50μM Silibinin promoted osteoblast differentiation, which was determined at cellular and molecular levels. Recent studies indicated the role of microRNAs (miRNAs) in osteogenesis and we found that the Silibinin released from scaffolds regulated miRNAs that control the bone morphogenetic protein pathway. Hence, our results suggest the potential for sustained and prolonged release of Silibinin to promote bone formation and, thus, these Alg/Gel-SCN scaffolds may be candidates for bone tissue engineering applications.

A dual discrimination mode for improved specificity towards let-7a detection via a single-base mutated padlock probe-based exponential rolling circle amplification

MicroRNA (miRNA) family members are usually highly homologous sequences, and it is a challenging task to selectively detect one miRNA member from other family members in medical diagnosis. Here, we describe the design of a dual discrimination mode for improved specificity towards let-7a detection over the other members of the let-7 family, in which an intentional base mutation was introduced into the padlock probe of an exponential rolling circle amplification. The inherent discrimination power of the padlock probe and the introduced base mutation constituted a dual discrimination mode, which provided enhanced specificity for let-7a, even over single-base mismatched family sequences. Furthermore, the assay enabled the quantitative detection of let-7a in a dynamic range from 200 amol to 100 fmol. This technique has also been successfully applied to real small RNA samples extracted from human lung cancers. For the first time, through intentionally mutating one base on the padlock probe of the exponential rolling circle amplification (RCA), we improved the discrimination capability for let-7 family members, while maintaining adequate sensitivity. Overall, this dual discrimination mode and the high amplification strategy have the potential to be extended to other short, but highly homologous, miRNA sequences.

MicroRNA-15b-5p targets ERK1 to regulate proliferation and apoptosis in rat PC12 cells

MicroRNAs (miRNAs) play an important role in multiple biological processes, and many miRNAs have been shown to regulate cell proliferation and apoptosis. In this study, we investigated the role of miR-15b-5p in cell proliferation and apoptosis in PC12 cells. We found that overexpression of miR-15b-5p could decrease cell proliferation and induce apoptosis and cytotoxic activities in PC12 cells. Bioinformatics analysis and luciferase activities assays showed that miR-15b-5p might target extracellular signal-regulated kinase 1 (ERK1) by binding to its 3'-untranslated region (3'-UTR). Moreover, we also found that overexpression of ERK1 could attenuate the effects of miR-15b-5p in PC12 cells. Finally, our results suggest that miR-15b-5p might inhibit cell proliferation and induce apoptosis in PC12 cells by targeting ERK1.

Suppressing the molecular signaling pathways involved in inflammation and cancer in breast cancer cell lines MDA-MB-231 and MCF-7 by miR-590

Breast cancer is the most frequent cancer among women worldwide. Tumor immunology suggests relationships between the immune system, chronic inflammation, and cancer. The immune system may either prevent or promote carcinogenesis. Here, we evaluated molecular signaling pathways common in inflammation and cancer and detected the microRNAs which play pivotal roles in mediating these pathways. Using bioinformatics assays, signaling pathways common in inflammation and cancer, and microRNAs mediating these pathways were identified. MiR-590 was selected and cloned into the pLenti-III-eGFP vector and transfected into the breast cancer cell lines. The expression level of microRNA and the candidate genes was evaluated by real-time quantitative reverse transcription polymerase chain reaction, and the apoptosis level in transfected cells was measured by Annexin V-7AAD assay. The cell migration was tested by real-time quantitative reverse transcription polymerase chain reaction for MMP2/MMP9. The expression levels of miR-590 and the selected genes (i.e. JAK2, PI3K, MAPK1, and CREB) were measured 72 h after transfection. While miR-590 showed an over-expression, the genes were significantly down-regulated. A significant increase was observed in apoptosis level in both cell lines and MMP2/MMP9 was significantly decreased in MDA-MB-231 cells. MiR-590 was selected as a microRNA which triggers and down-regulates critical genes of signaling pathways similar in cancer and inflammation. Following the miR-590 treatment, JAK2, PI3K, MAPK1, and CREB were down-regulated and the apoptosis level was increased in breast cancer cell lines. Apparently, some microRNAs can be good candidates for novel treatments of cancer. Although miR-590 showed good results in this study, further studies are required to investigate the role of miR-590 in breast cancer therapy.

Pulsed Electromagnetic Field Regulates MicroRNA 21 Expression to Activate TGF-β Signaling in Human Bone Marrow Stromal Cells to Enhance Osteoblast Differentiation

Pulsed electromagnetic fields (PEMFs) have been documented to promote bone fracture healing in nonunions and increase lumbar spinal fusion rates. However, the molecular mechanisms by which PEMF stimulates differentiation of human bone marrow stromal cells (hBMSCs) into osteoblasts are not well understood. In this study the PEMF effects on hBMSCs were studied by microarray analysis. PEMF stimulation of hBMSCs' cell numbers mainly affected genes of cell cycle regulation, cell structure, and growth receptors or kinase pathways. In the differentiation and mineralization stages, PEMF regulated preosteoblast gene expression and notably, the transforming growth factor-beta (TGF-β) signaling pathway and microRNA 21 (miR21) were most highly regulated. PEMF stimulated activation of Smad2 and miR21-5p expression in differentiated osteoblasts, and TGF-β signaling was essential for PEMF stimulation of alkaline phosphatase mRNA expression. Smad7, an antagonist of the TGF-β signaling pathway, was found to be miR21-5p's putative target gene and PEMF caused a decrease in Smad7 expression. Expression of Runx2 was increased by PEMF treatment and the miR21-5p inhibitor prevented the PEMF stimulation of Runx2 expression in differentiating cells. Thus, PEMF could mediate its effects on bone metabolism by activation of the TGF-β signaling pathway and stimulation of expression of miR21-5p in hBMSCs.

MicroRNA Mediating Networks in Granulosa Cells Associated with Ovarian Follicular Development

Ovaries, which provide a place for follicular development and oocyte maturation, are important organs in female mammals. Follicular development is complicated physiological progress mediated by various regulatory factors including microRNAs (miRNAs). To demonstrate the role of miRNAs in follicular development, this study analyzed the expression patterns of miRNAs in granulosa cells through investigating three previous datasets generated by Illumina miRNA deep sequencing. Furthermore, via bioinformatic analyses, we dissected the associated functional networks of the observed significant miRNAs, in terms of interacting with signal pathways and transcription factors. During the growth and selection of dominant follicles, 15 dysregulated miRNAs and 139 associated pathways were screened out. In comparison of different styles of follicles, 7 commonly abundant miRNAs and 195 pathways, as well as 10 differentially expressed miRNAs and 117 pathways in dominant follicles in comparison with subordinate follicles, were collected. Furthermore, SMAD2 was identified as a hub factor in regulating follicular development. The regulation of miR-26a/b on smad2 messenger RNA has been further testified by real time PCR. In conclusion, we established functional networks which play critical roles in follicular development including pivotal miRNAs, pathways, and transcription factors, which contributed to the further investigation about miRNAs associated with mammalian follicular development.

FOXO1-suppressed miR-424 regulates the proliferation and osteogenic differentiation of MSCs by targeting FGF2 under oxidative stress

Recently, microRNAs (miRNAs) have been identified as key regulators of the proliferation and differentiation of mesenchymal stem cells (MSCs). Our previous in vivo study and other in vitro studies using miRNA microarrays suggest that miR-424 is involved in the regulation of bone formation. However, the role and mechanism of miR-424 in bone formation still remain unknown. Here, we identified that the downregulation of miR-424 mediates bone formation under oxidative stress, and we explored its underlying mechanism. Our results showed that miR-424 was significantly downregulated in an anterior lumbar interbody fusion model of pigs and in a cell model of oxidative stress induced by H₂O₂. The overexpression of miR-424 inhibited proliferation and osteogenic differentiation shown by a decrease in alkaline phosphatase (ALP) activity, mineralization and osteogenic markers, including RUNX2 and ALP, whereas the knockdown of miR-424 led to the opposite results. Moreover, miR-424 exerts its effects by targeting FGF2. Furthermore, we found that FOXO1 suppressed miR-424 expression and bound to its promoter region. FOXO1 enhanced proliferation and osteogenic differentiation in part through the miR-424/FGF2 pathway. These results indicated that FOXO1-suppressed miR-424 regulates both the proliferation and osteogenic differentiation of MSCs via targeting FGF2, suggesting that miR-424 might be a potential novel therapeutic strategy for promoting bone formation.

MiR-222 in Cardiovascular Diseases: Physiology and Pathology

MicroRNAs (miRNAs and miRs) are endogenous 19–22 nucleotide, small noncoding RNAs with highly conservative and tissue specific expression. They can negatively modulate target gene expressions through decreasing transcription or posttranscriptional inducing mRNA decay. Increasing evidence suggests that deregulated miRNAs play an important role in the genesis of cardiovascular diseases. Additionally, circulating miRNAs can be biomarkers for cardiovascular diseases. MiR-222 has been reported to play important roles in a variety of physiological and pathological processes in the heart. Here we reviewed the recent studies about the roles of miR-222 in cardiovascular diseases. MiR-222 may be a potential cardiovascular biomarker and a new therapeutic target in cardiovascular diseases.

Dicer ablation in osteoblasts by Runx2 driven cre-loxP recombination affects bone integrity, but not glucocorticoid-induced suppression of bone formation

Glucocorticoid-induced osteoporosis (GIO) is one of the major side effects of long-term glucocorticoid (GC) therapy mediated mainly via the suppression of bone formation and osteoblast differentiation independently of GC receptor (GR) dimerization. Since microRNAs play a critical role in osteoblast differentiation processes, we investigated the role of Dicer dependent microRNAs in the GC-induced suppression of osteoblast differentiation. MicroRNA sequencing of dexamethasone-treated wild-type and GR dimer-deficient mesenchymal stromal cells revealed GC-controlled miRNA expression in a GR dimer-dependent and GR dimer-independent manner. To determine the functional relevance of mature miRNAs in GC-induced osteoblast suppression, mice with an osteoblast-specific deletion of Dicer (Dicer^Runx2Cre) were exposed to glucocorticoids. In vitro generated Dicer-deficient osteoblasts were treated with dexamethasone and analyzed for proliferation, differentiation and mineralization capacity. In vivo, abrogation of Dicer-dependent miRNA biogenesis in osteoblasts led to growth retardation and impaired bone formation. However, subjecting these mice to GIO showed that bone formation was similar reduced in Dicer^Runx2Cre mice and littermate control mice upon GC treatment. In line, differentiation of Dicer deficient osteoblasts was suppressed to the same extent as wild type cells by GC treatment. Therefore, Dicer-dependent small RNA biogenesis in osteoblasts plays only a minor role in the pathogenesis of GC-induced inhibition of bone formation.

The Role of MicroRNA, miR-24, and Its Target CHI3L1 in Osteomyelitis Caused by Staphylococcus aureus

Osteomyelitis is a debilitating infectious disease of the bone which is predominantly caused by Staphylococcus aureus (S. aureus). MicroRNAs (miRNAs) have been shown to play a regulatory role in osteogenesis. In the present study, the expression levels of miRNAs proposed to potentially play a regulatory role in bone formation or differentiation (miR-24, miR-29b, miR-200a, miR-208, miR-322) were analyzed in the whole blood of patients with bacterial osteomyelitis or healthy controls, and in MC3T3-E1 cells infected with S. aureus by qRT-PCR. The expression of miR-24 was significantly down-regulated in osteomyelitis patients and S. aureus-infected MC3T3-E1 cells compared with the healthy controls or untreated control cells. Moreover, our results showed that S. aureus inhibited MC3T3-E1 cell proliferation, induced osteoblast apoptosis and prohibited bone formation and mineralization. We found that overexpression of miR-24 could reduce the effects of S. aureus, while inhibition of miR-24 intensified the effects. We also demonstrated that miR-24 suppressed the expression of chitinase 3-like 1 (CHI3L1) mRNA, thought to mediate multiple signaling pathways, by directly binding to the 3'-untranslated region.

Transdentinal photobiostimulation of stem cells from human exfoliated primary teeth

AIM

To evaluate the effects of infrared light-emitting diode (LED) irradiation on stem cells from human exfoliated deciduous teeth (SHEDs).

METHODOLOGY

Exfoliated primary teeth were obtained (n = 3), and SHEDs obtained from the teeth were seeded on the pulpal surface of 0.2-mm-thick dentine discs produced from permanent molars. The cells were incubated for 24 h by placing the discs in plain Dulbecco's modified Eagle's medium (DMEM). The DMEM was then replaced with new culture medium formulated for odontoblast differentiation. After 12 h in the second medium, SHEDs were irradiated through the dentine discs using an infrared LED (850 nm) with a power density of 80 mW cm^-2 . Energy doses (EDs) delivered to the occlusal surface of the dentine discs were 0 (control), 2 and 4 J cm^-2 (n = 6). Subsequent tests were performed 72 h after irradiation. These tests included cell viability (MTT), alkaline phosphatase activity (ALP), total protein production (TP), scanning electron microscopy (SEM), as well as gene expression for ALP, Col I, DSPP and DMP-1. Data were analysed using Kruskal-Wallis and Mann-Whitney t-tests (α = 0.05).

RESULTS

Both EDs (2 and 4 J cm^-2 ) significantly increased cell viability and ALP activity. For TP, ALP and Col I gene expression, only the 4 J cm^-2 group had significantly higher values compared to the control group. Cell morphology was not affected by irradiation.

CONCLUSION

Infrared LED irradiation was capable of biostimulating SHEDs through a 0.2 mm thickness of dentine, especially at the 4 J cm^-2 level.

Dysregulation of ossification-related miRNAs in circulating osteogenic progenitor cells obtained from patients with aortic stenosis

CAVD (calcific aortic valve disease) is the defining feature of AS (aortic stenosis). The present study aimed to determine whether expression of ossification-related miRNAs is related to differentiation intro COPCs (circulating osteogenic progenitor cells) in patients with CAVD. The present study included 46 patients with AS and 46 controls. Twenty-nine patients underwent surgical AVR (aortic valve replacement) and 17 underwent TAVI (transcatheter aortic valve implantation). The number of COPCs was higher in the AS group than in the controls (P<0.01). Levels of miR-30c were higher in the AS group than in the controls (P<0.01), whereas levels of miR-106a, miR-148a, miR-204, miR-211, miR-31 and miR-424 were lower in the AS group than in the controls (P<0.01). The number of COPCs and levels of osteocalcin protein in COPCs were positively correlated with levels of miR-30a and negatively correlated with levels of the remaining miRNAs (all P<0.05). The degree of aortic valve calcification was weakly positively correlated with the number of COPCs and miR-30c levels. The number of COPCs and miR-30c levels were decreased after surgery, whereas levels of the remaining miRNAs were increased (all P<0.05). Changes in these levels were greater after AVR than after TAVI (all P<0.05). In vitro study using cultured peripheral blood mononuclear cells transfected with each ossification-related miRNA showed that these miRNAs controlled levels of osteocalcin protein. In conclusion, dysregulation of ossification-related miRNAs may be related to the differentiation into COPCs and may play a significant role in the pathogenesis of CAVD.

Paeoniflorin inhibits doxorubicin-induced cardiomyocyte apoptosis by downregulating microRNA-1 expression

Doxorubicin (DOX) is an effective anthracycline anti-tumor antibiotic. Because of its cardiotoxicity, the clinical application of DOX is limited. Paeoniflorin (PEF), a monoterpene glucoside extracted from the dry root of Paeonia, is reported to exert multiple beneficial effects on the cardiovascular system. The present study was designed to explore the protective effect of PEF against DOX-induced cardiomyocyte apoptosis and the underlying mechanism. In cultured H9c2 cells, PEF (100 µmol/l) was added for 2 h prior to exposure to DOX (5 µmol/l) for 24 h. Cell viability, creatine kinase activity, cardiomyocyte apoptosis, intracellular reactive oxygen species (ROS) levels, and the expression of microRNA-1 (miR-1) and B-cell lymphoma 2 (Bcl-2) were measured following treatment with PEF and/or DOX. The results showed that treatment with DOX notably induced cardiomyocyte apoptosis, concomitantly with enhanced ROS generation, upregulated miR-1 expression and downregulated Bcl-2 expression. These effects of DOX were significantly inhibited by pretreatment of the cells with PEF. These results suggest that the inhibitory effect of PEF on DOX-induced cardiomyocyte apoptosis may be associated with downregulation of miR-1 expression via a reduction in ROS generation.

A Combinatorial effect of carboxymethyl cellulose based scaffold and microRNA-15b on osteoblast differentiation

The present study was aimed to synthesize and characterize a bio-composite scaffold containing carboxymethyl cellulose (CMC), zinc doped nano-hydroxyapatite (Zn-nHAp) and ascorbic acid (AC) for bone tissue engineering applications. The fabricated bio-composite scaffold was characterized by SEM, FT-IR and XRD analyses. The ability of scaffold along with a bioactive molecule, microRNA-15b (miR-15b) for osteo-differentiation at cellular and molecular levels was determined using mouse mesenchymal stem cells (mMSCs). miR-15b acts as posttranscriptional gene regulator and regulates osteoblast differentiation. The scaffold and miR-15b were able to promote osteoblast differentiation; when these treatments were combined together on mMSCs, there was an additive effect on promotion of osteoblast differentiation. Thus, it appears that the combination of CMC/Zn-nHAp/AC scaffold with miR-15b would provide more efficient strategy for treating bone related defects and bone regeneration.

MicroRNA-24 can control triacylglycerol synthesis in goat mammary epithelial cells by targeting the fatty acid synthase gene

In nonruminants it has been demonstrated that microRNA-24 (miR-24) is involved in preadipocyte differentiation, hepatic lipid, and plasma triacylglycerol synthesis. However, its role in ruminant mammary gland remains unclear. In this study we measured miR-24 expression in goat mammary gland tissue at 4 different stages of lactation and observed that it had highest expression at peak lactation when compared with the dry period. Overexpression or downregulation of miR-24 in goat mammary epithelial cells (GMEC) strongly affected fatty acid profiles; in particular, miR-24 enhanced unsaturated fatty acid concentration. Additional effects of miR-24 included changes in triacylglycerol content and the expression of fatty acid synthase, sterol regulatory element binding transcription protein 1, stearoyl-CoA desaturase, glycerol-3-phosphate acyltransferase mitochondrial, and acetyl-CoA carboxylase. Luciferase reporter assay confirmed that fatty acid synthase is a target of miR-24. Taken together, these results not only highlight the physiological importance of miR-24 in fatty acid metabolism in GMEC, but also laid the foundation for further research on regulatory mechanisms among miR-24 and other microRNA expressed in GMEC.