Dysregulation of MicroRNAs in Adult Osteogenesis Imperfecta: The miROI Study

As epigenetic regulators of gene expression, circulating micro-RiboNucleic Acids (miRNAs) have been described in several bone diseases as potential prognostic markers. The aim of our study was to identify circulating miRNAs potentially associated with the severity of osteogenesis imperfecta (OI) in three steps. We have screened by RNA sequencing for the miRNAs that were differentially expressed in sera of a small group of OI patients versus controls and then conducted a validation phase by RT-qPCR analysis of sera of a larger patient population. In the first phase of miROI, we found 79 miRNAs that were significantly differentially expressed. We therefore selected 19 of them as the most relevant. In the second phase, we were able to validate the significant overexpression of 8 miRNAs in the larger OI group. Finally, we looked for a relationship between the level of variation of the validated miRNAs and the clinical characteristics of OI. We found a significant difference in the expression of two microRNAs in those patients with dentinogenesis imperfecta. After reviewing the literature, we found 6 of the 8 miRNAs already known to have a direct action on bone homeostasis. Furthermore, the use of a miRNA-gene interaction prediction model revealed a 100% probability of interaction between 2 of the 8 confirmed miRNAs and COL1A1 and/or COL1A2. This is the first study to establish the miRNA signature in OI, showing a significant modification of miRNA expression potentially involved in the regulation of genes involved in the physiopathology of OI. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

miR-196b-5p Regulates Osteoblast and Osteoclast Differentiation and Bone Homeostasis by Targeting SEMA3A

miR-196b-5p plays a role in various malignancies. We have recently reported its function in regulating adipogenesis. However, it remains to be clarified whether and how miR-196b-5p affects bone cells and bone homeostasis. In this study, in vitro functional experiments showed an inhibitory effect of miR-196b-5p on osteoblast differentiation. Mechanistic explorations revealed that miR-196b-5p directly targeted semaphorin 3a (Sema3a) and inhibited Wnt/β-catenin signaling. SEMA3A attenuated the impaired osteogenesis induced by miR-196b-5p. Osteoblast-specific miR-196b transgenic mice showed significant reduction of bone mass. Trabecular osteoblasts were reduced and bone formation was suppressed, whereas osteoclasts, marrow adipocytes, and serum levels of bone resorption markers were increased in the transgenic mice. The osteoblastic progenitor cells from the transgenic mice had decreased SEMA3A levels and exhibited retarded osteogenic differentiation, whereas those marrow osteoclastic progenitors exhibited enhanced osteoclastogenic differentiation. miR-196b-5p and SEMA3A oppositely regulated the expression of receptor activator of nuclear factor-κB ligand and osteoprotegerin. The calvarial osteoblastic cells expressing the transgene promoted osteoclastogenesis, whereas the osteoblasts overexpressing Sema3a inhibited it. Finally, in vivo transfection of miR-196b-5p inhibitor to the marrow reduced ovariectomy-induced bone loss in mice. Our study has identified that miR-196b-5p plays a key role in osteoblast and osteoclast differentiation and regulates bone homeostasis. Inhibition of miR-196b-5p may be beneficial for amelioration of osteoporosis. © 2023 American Society for Bone and Mineral Research (ASBMR).

MiRNAs regulate iron homeostasis in Paracoccidioides brasiliensis

During pathogen interaction with the host, several mechanisms are used to favor or inhibit the infectious process; one is called nutritional immunity, characterized by restriction of micronutrients to pathogens. Several studies on fungi of the Paracoccidioides complex, have demonstrated that these pathogens remodel their metabolic pathways to overcome the hostile condition imposed by the host. However, molecular mechanisms that control the regulation of those metabolic changes are not fully understood. Therefore, this work characterizes the expression profile of miRNAs during iron deprivation and describes metabolic pathways putatively regulated by those molecules. Through analysis of RNAseq, 45 miRNAs were identified and eight presented alterations in the expression profile during iron deprivation. Among the differentially regulated miRNAs, five were more abundant in yeast cells during iron deprivation and interestingly, the analyses of genes potentially regulated by those five miRNAs, pointed to metabolic pathways as oxidative phosphorylation, altered in response to iron deprivation. In addition, miRNAs with more abundance in iron presence, have as target genes encoding transcriptional factors related to iron homeostasis and uptake. Therefore, we suggest that miRNAs produced by Paracoccidioides brasiliensis may contribute to the adaptive responses of this fungus in iron starvation environment.

The miR-143/145 Cluster, a Novel Diagnostic Biomarker in Chondrosarcoma, Acts as a Tumor Suppressor and Directly Inhibits Fascin-1

Chondrosarcoma is the second most frequent bone sarcoma. Due to the inherent chemotherapy and radiotherapy resistance and absence of known therapeutic targets, clinical management is limited to surgical resection. Consequently, patients with advanced disease face a poor prognosis. Hence, elucidating regulatory networks governing chondrosarcoma pathogenesis is vital for development of effective therapeutic strategies. Here, miRNA and mRNA next generation sequencing of different subtypes of human chondrogenic tumors in combination with in silico bioinformatics tools were performed with the aim to identify key molecular factors. We identified miR-143/145 cluster levels to inversely correlate with tumor grade. This deregulation was echoed in the miRNA plasma levels of patients and we provided the first evidence that circulating miR-145 is a potential noninvasive diagnostic biomarker and can be valuable as an indicator to improve the currently challenging diagnosis of cartilaginous bone tumors. Additionally, artificial upregulation of both miRNAs impelled a potent tumor suppressor effect in vitro and in vivo in an orthotopic xenograft mouse model. A combined in silico/sequencing approach revealed FSCN1 as a direct target of miR-143/145, and its depletion phenotypically resembled miR-143/145 upregulation in vitro. Last, FSCN1 is a malignancy-promoting factor associated with aggressive chondrosarcoma progression. Our findings underscore miR-143/145/FSCN1 as important players in chondrosarcoma and may potentially open new avenues for specific therapeutic intervention options. © 2020 American Society for Bone and Mineral Research.

Role of Epigenomics in Bone and Cartilage Disease

Phenotypic variation in skeletal traits and diseases is the product of genetic and environmental factors. Epigenetic mechanisms include information-containing factors, other than DNA sequence, that cause stable changes in gene expression and are maintained during cell divisions. They represent a link between environmental influences, genome features, and the resulting phenotype. The main epigenetic factors are DNA methylation, posttranslational changes of histones, and higher-order chromatin structure. Sometimes non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are also included in the broad term of epigenetic factors. There is rapidly expanding experimental evidence for a role of epigenetic factors in the differentiation of bone cells and the pathogenesis of skeletal disorders, such as osteoporosis and osteoarthritis. However, different from genetic factors, epigenetic signatures are cell- and tissue-specific and can change with time. Thus, elucidating their role has particular difficulties, especially in human studies. Nevertheless, epigenomewide association studies are beginning to disclose some disease-specific patterns that help to understand skeletal cell biology and may lead to development of new epigenetic-based biomarkers, as well as new drug targets useful for treating diffuse and localized disorders. Here we provide an overview and update of recent advances on the role of epigenomics in bone and cartilage diseases. © 2019 American Society for Bone and Mineral Research.

MicroRNA and Human Bone Health

The small non‐coding microRNAs (miRNAs) are post‐transcription regulators that modulate diverse cellular process in bone cells. Because optimal miRNA targeting is essential for their function, single‐nucleotide polymorphisms (SNPs) within or proximal to the loci of miRNA (miR‐SNPs) or mRNA (PolymiRTS) could potentially disrupt the miRNA‐mRNA interaction, leading to changes in bone metabolism and osteoporosis. Recent human studies of skeletal traits using miRNA profiling, genomewide association studies, and functional studies started to decipher the complex miRNA regulatory network. These studies have indicated that miRNAs may be a promising bone marker. This review focuses on human miRNA studies on bone traits and discusses how genetic variants affect bone metabolic pathways. Major ex vivo investigations using human samples supported with animal and in vitro models have shed light on the mechanistic role of miRNAs. Furthermore, studying the miRNAs’ signatures in secondary osteoporosis and osteoporotic medications such as teriparatide (TPTD) and denosumab (DMab) have provided valuable insight into clinical management of the disease. © 2018 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research

Synovium-Derived MicroRNAs Regulate Bone Pathways in Rheumatoid Arthritis

Articular bone erosion in rheumatoid arthritis (RA) is mediated by the interaction between inflammation and pathways regulating bone metabolism. Inflammation promotes osteoclastogenesis and also inhibits osteoblast function, further contributing to the persistence of erosions. MicroRNAs (miRNAs) are important regulators of skeletal remodeling and play a role in RA pathogenesis. We therefore determined the expression of miRNAs in inflamed synovial tissue and the role they play in pathways regulating osteoblast and osteoclast function. Using the serum transfer mouse model of RA in C57BL/6 mice, we performed Fluidigm high-throughput qPCR-based screening of miRNAs from nonarthritic and arthritic mice. Global gene expression profiling was also performed on Affymetrix microarrays from these same synovial samples. miRNA and mRNA expression profiles were subjected to comparative bioinformatics. A total of 536 upregulated genes and 417 downregulated genes were identified that are predicted targets of miRNAs with reciprocal expression changes. Gene ontology analysis of these genes revealed significant enrichment in skeletal pathways. Of the 22 miRNAs whose expression was most significantly changed (p < 0.01) between nonarthritic and arthritic mice, we identified their targets that both inhibit and promote bone formation. These miRNAs are predicted to target Wnt and BMP signaling pathway components. We validated miRNA array findings and demonstrated that secretion of miR-221-3p in exosomes was upregulated by synovial fibroblasts treated with the proinflammatory cytokine TNF. Overexpression of miR-221-3p suppressed calvarial osteoblast differentiation and mineralization in vitro. These results suggest that miRNAs derived from inflamed synovial tissues may regulate signaling pathways at erosion sites that affect bone loss and potentially also compensatory bone formation. © 2016 American Society for Bone and Mineral Research.

MicroRNA-150 Protects Against Pressure Overload-Induced Cardiac Hypertrophy

Cardiac hypertrophy is the response of the heart to a variety of hypertrophic stimuli; this condition progresses to heart failure and sudden death. MicroRNAs (miRs) are a family of small, non-coding RNAs that mediate posttranscriptional gene silencing. Recent studies have identified miRs as important regulators in cardiac hypertrophy. One specific miR, miR-150 has been reported to be downregulated in hypertrophic murine hearts. However, the role of miR-150 as a regulator of cardiac hypertrophy remains unclear. In the present study, we used gain-of-function and loss-of-function approaches to investigate the functional roles of miR-150 in cardiac hypertrophy induced by aortic banding. The extent of the cardiac hypertrophy was evaluated by echocardiography and by pathological and molecular analyses of heart samples. Our results revealed that transgenic mice that overexpress miR-150 in the heart were resistant to cardiac hypertrophy and fibrosis through down-regulation of serum response factor (SRF). Conversely, the loss of function of miR-150 by genetic knockdown or antagomiR approaches produced the opposite effects. These studies suggest that miR-150 plays an important role in the regulation of cardiac hypertrophy and SRF is involved in miR-150 mediated anti-hypertrophic effect. Thus, miR-150 may be a new therapeutic target for cardiac hypertrophy.

MiR-17-5p up-regulates YES1 to modulate the cell cycle progression and apoptosis in ovarian cancer cell lines

MicroRNAs (miRNAs) are small, non-coding RNAs that participate in the regulation of gene expression. Although many studies have demonstrated the involvement of miR-17-5p in different cancers, little is known to its function in ovarian cancer. In this study, we demonstrated that overexpression of miR-17-5p was able to enhance cell proliferation by promoting G1/S transition of the cell cycle and suppressing apoptosis in ES-2 and OVCAR3 cell lines, whereas inhibition of miR-17-5p yielded the reverse phenotype. YES1 was identified as a novel target gene of miR-17-5p. Moreover, miR-17-5p was found to directly bind to the 3'UTR of YES1 mRNA and up-regulated its expression. Furthermore, knockdown of YES1 led to the suppression of proliferation and induced cell cycle arrest in ES-2 and OVCAR3 cells. Ectopic expression of YES1 was able to reverse the effects of miR-17-5p inhibition. Collectively, our results indicated that miR-17-5p might play a role in human ovarian cancer by up-regulating YES1 expression. J. Cell. Biochem. 116: 1050-1059, 2015. © 2015 Wiley Periodicals, Inc.

Regulation of hypoxia-inducible factor-1a by reactive oxygen species: new developments in an old debate

Hypoxia-Inducible Factor-1 (HIF-1) has been largely studied for its role in cell survival in hypoxic conditions. The regulation of HIF-1 is a complex process and involves a number of molecules and pathways. Among these mechanisms a direct regulatory role of reactive oxygen species (ROS) on HIF-1 alpha subunit has received a great deal of attention and the existing body of literature includes many contradictory findings. Other intermediates such as nitric oxide (NO), specific microRNAs (miR), and transcriptional and post-translational modification have also been implicated as players in ROS mediated HIF-1a regulation. The focus of this review is to present the past conflicting evidence along with more recent findings in order to relate various aspects of this complex process. Aside from the direct role of ROS on HIF-1a regulation under hypoxia and normoxia, we analyzed the effect of different sources and concentrations of NO and the interplay between superoxide (SO) and NO in this process. We also present findings on transcriptional and translational regulation of HIF-1a via ROS and the interplay with microRNAs in this process. This review further provides insight on ERK and PI3K/AKT signaling as a common mechanism relating several pathways of ROS mediated HIF-1a regulation. Ultimately further research and discovery regarding HIF-1 regulation by oxidative stress is warranted for better understanding of disease development and potential therapeutics for pathologies such as cancer, inflammatory diseases, and ischemia-reperfusion injury.

Utility of Select Plasma MicroRNA for Disease and Cardiovascular Risk Assessment in Patients with Rheumatoid Arthritis

OBJECTIVE

MicroRNA (miRNA) are small noncoding RNA that posttranscriptionally regulate gene expression and serve as potential mediators and markers of disease. Recently, plasma miR-24-3p and miR-125a-5p concentrations were shown to be elevated in rheumatoid arthritis (RA) and useful for RA diagnosis. We assessed the utility of 7 candidate plasma miRNA, selected for biological relevance, for RA diagnosis and use as markers of disease activity and subclinical atherosclerosis in RA.

METHODS

The cross-sectional study included 168 patients with RA and 91 control subjects of similar age, race, and sex. Plasma concentrations of miR-15a-5p, miR-24-3p, miR-26a-5p, miR-125a-5p, miR-146a-5p, miR-155-5p, and miR-223-3p were measured by quantitative PCR. Utility of plasma miRNA concentrations for RA diagnosis was assessed by area under the receiver-operating characteristic curve (AUROC). Associations between plasma miRNA concentrations and RA disease activity and coronary artery calcium score were assessed by Spearman correlations.

RESULTS

Plasma concentrations of miR-15a-5p, miR-24-3p, miR-26a-5p, miR-125a-5p, miR-146a-5p, miR-155-5p, and miR-223-3p were significantly increased in patients with RA. The highest AUROC for diagnosis of RA (AUROC = 0.725) was found in miR-24-3p, including among rheumatoid factor-negative patients (AUROC = 0.772). Among all patients with RA, the combination of miR-24-3p, miR-26a-5p, and miR-125a-5p improved the model modestly (AUROC = 0.747). One miRNA, miR-155-5p, was weakly inversely associated with swollen joint count (p = 0.024), but no other miRNA were associated with disease activity or coronary artery calcium score.

CONCLUSION

The combination of miR-24-3p, miR-26a-5p, and miR-125a-5p had the strongest diagnostic accuracy for RA. Candidate miRNA had little or no association with RA disease activity or subclinical atherosclerosis.

Characterization of miR-210 in 3T3-L1 adipogenesis

Although accumulating evidences indicate that miRNA emerge as a vital player in cell growth, development, and differentiation, how they contribute to the process of adipocyte differentiation remains elusive. In the present study, we revealed that the expression level of miR-210 was dramatically upregulated during 3T3-L1 adipogenesis. Ectopic introduction of miR-210 into 3T3-L1 cells promoted terminal differentiation as well as the expression of adipogenic markers. MTT assay showed that miR-210 significantly inhibited cell proliferation whereas the BrdU incorporation assay and flow cytometry analysis showed that miR-210 did not impair G1/S phase transition. Further experiments demonstrated that enhanced expression of miR-210 in 3T3-L1 cells provoked adipocyte differentiation via activation of PI3K/Akt pathway by targeting SHIP1, a negative regulator of PI3K/Akt pathway. Moreover, blockade of endogenous miR-210 during adipogenesis significantly repressed adipocyte differentiation. In summary, we have identified miR-210 as an important positive regulator in adipocyte differentiation through the activation of PI3K/Akt pathway.

Changes of microRNA profile and microRNA-mRNA regulatory network in bones of ovariectomized mice

Growing evidence shows the possibility of a role of microRNAs (miRNA) in regulating bone mass. We investigated the change of miRNAs and mRNA expression profiles in bone tissue in an ovariectomized mice model and evaluated the regulatory mechanism of bone mass mediated by miRNAs in an estrogen-deficiency state. Eight-week-old female C3H/HeJ mice underwent ovariectomy (OVX) or sham operation (Sham-op), and their femur and tibia were harvested to extract total bone RNAs after 4 weeks for microarray analysis. Eight miRNAs (miR-127, -133a, -133a*, -133b, -136, -206, -378, -378*) were identified to be upregulated after OVX, whereas one miRNA (miR-204) was downregulated. Concomitant analysis of mRNA microarray revealed that 658 genes were differentially expressed between OVX and Sham-op mice. Target prediction of differentially expressed miRNAs identified potential targets, and integrative analysis using the mRNA microarray results showed that PPARγ and CREB pathways are activated in skeletal tissues after ovariectomy. Among the potential candidates of miRNA, we further studied the role of miR-127 in vitro, which exhibited the greatest changes after OVX. We also studied the effects of miR-136, which has not been studied in the context of bone mass regulation. Transfection of miR-127 inhibitor has enhanced osteoblastic differentiation in UAMS-32 cells as measured by alkaline phosphatase activities and mRNA expression of osteoblast-specific genes, whereas miR-136 precursor has inhibited osteoblastic differentiation. Furthermore, transfection of both miR-127 and miR-136 inhibitors enhanced the osteocyte-like morphological changes and survival in MLO-Y4 cells, whereas precursors of miR-127 and -136 have aggravated dexamethasone-induced cell death. Both of the precursors enhanced osteoclastic differentiation in bone marrow macrophages, indicating that both miR-127 and -136 are negatively regulating bone mass. Taken together, these results suggest a novel insight into the association between distinct miRNAs expression and their possible role through regulatory network with mRNAs in the pathogenesis of estrogen deficiency-induced osteoporosis.

Inhibition of miR-92a enhances fracture healing via promoting angiogenesis in a model of stabilized fracture in young mice

MicroRNAs (miRNAs) are endogenous small noncoding RNAs regulating the activities of target mRNAs and cellular processes. Although no miRNA has been reported to play an important role in the regulation of fracture healing, several miRNAs control key elements in tissue repair processes such as inflammation, hypoxia response, angiogenesis, stem cell differentiation, osteogenesis, and chondrogenesis. We compared the plasma concentrations of 134 miRNAs in 4 patients with trochanteric fractures and 4 healthy controls (HCs), and the levels of six miRNAs were dysregulated. Among these miRNAs, miR-92a levels were significantly decreased 24 hours after fracture, compared to HCs. In patients with a trochanteric fracture or a lumbar compression fracture, the plasma concentrations of miR-92a were lower on days 7 and 14, but had recovered on day 21 after the surgery or injury. To determine whether systemic downregulation of miR-92a can modulate fracture healing, we administered antimir-92a, designed using locked nucleic acid technology to inhibit miR-92a, to mice with a femoral fracture. Systemic administration of antimir-92a twice a week increased the callus volume and enhanced fracture healing. Enhancement of fracture healing was also observed after local administration of antimir-92a. Neovascularization was increased in mice treated with antimir-92a. These results suggest that plasma miR-92a plays a crucial role in bone fracture healing in human and that inhibition of miR-92a enhances fracture healing through angiogenesis and has therapeutic potential for bone repair.