MicroRNA-602 and microRNA-608 regulate sonic hedgehog expression via target sites in the coding region in human chondrocytes

Epigenetic control of cell signalling in cancer stem cells

The self-renewing cancer stem cells (CSCs) represent one of the distinct cell populations occurring in a tumour that can differentiate into multiple lineages. This group of sparsely abundant cells play a vital role in tumour survival and resistance to different treatments during cancer. The lack of exclusive markers associated with CSCs makes diagnosis and prognosis in cancer patients extremely difficult. This calls for the identification of unique regulators and markers for CSCs. Various signalling pathways like the Wnt/β-catenin pathway, Hedgehog pathway, Notch pathway, and TGFβ/BMP play a major role in the regulation and maintenance of CSCs. Epigenetic regulatory mechanisms add another layer of complexity to control these signalling pathways. In this chapter, we discuss about the role of epigenetic mechanisms in regulating the cellular signalling pathways in CSCs. The epigenetic regulatory mechanisms such as DNA methylation, histone modification and microRNAs can modulate the diverse effectors of signalling pathways and consequently the growth, differentiation and tumorigenicity of CSCs. In the end, we briefly discuss the therapeutic potential of targeting these epigenetic regulators and their target genes in CSCs.

Emerging role of non-coding RNAs in the regulation of Sonic Hedgehog signaling pathway

Sonic Hedgehog (Shh) signaling cascade is one of the complex signaling pathways that control the accurately organized developmental processes in multicellular organisms. This pathway has fundamental roles in the tumor formation and induction of resistance to conventional therapies. Numerous non-coding RNAs (ncRNAs) have been found to interact with Shh pathway to induce several pathogenic processes, including malignant and non-malignant disorders. Many of the Shh-interacting ncRNAs are oncogenes whose expressions have been increased in diverse malignancies. A number of Shh-targeting miRNAs such as miR-26a, miR-1471, miR-129-5p, miR-361-3p, miR-26b-5p and miR-361-3p have been found to be down-regulated in tumor tissues. In addition to malignant conditions, Shh-interacting ncRNAs can affect tissue regeneration and development of neurodegenerative disorders. XIST, LOC101930370, lncRNA-Hh, circBCBM1, SNHG6, LINC‐PINT, TUG1 and LINC01426 are among long non-coding RNAs/circular RNAs that interact with Shh pathway. Moreover, miR-424, miR-26a, miR-1471, miR-125a, miR-210, miR-130a-5p, miR-199b, miR-155, let-7, miR-30c, miR-326, miR-26b-5p, miR-9, miR-132, miR-146a and miR-425-5p are among Shh-interacting miRNAs. The current review summarizes the interactions between ncRNAs and Shh in these contexts.

Role of the hedgehog signaling pathway in rheumatic diseases: An overview

Hedgehog (Hh) signaling pathway is an evolutionarily conserved signal transduction pathway that plays an important regulatory role during embryonic development, cell proliferation, and differentiation of vertebrates, and it is often inhibited in adult tissues. Recent evidence has shown that Hh signaling also plays a key role in rheumatic diseases, as alterations in their number or function have been identified in rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, systemic sclerosis, and Sjogren's Syndrome. As a result, emerging studies have focused on the blockade of this pathogenic axis as a promising therapeutic target in several autoimmune disorders; nevertheless, a greater understanding of its contribution still requires further investigation. This review aims to elucidate the most recent studies and literature data on the pathogenetic role of Hh signaling in rheumatic diseases.

Epigenetic therapy targeting bone marrow mesenchymal stem cells for age-related bone diseases

As global aging accelerates, the prevention and treatment of age-related bone diseases are becoming a critical issue. In the process of senescence, bone marrow mesenchymal stem cells (BMSCs) gradually lose the capability of self-renewal and functional differentiation, resulting in impairment of bone tissue regeneration and disorder of bone tissue homeostasis. Alteration in epigenetic modification is an essential factor of BMSC dysfunction during aging. Its transferability and reversibility provide the possibility to combat BMSC aging by reversing age-related modifications. Emerging evidence demonstrates that epigenetic therapy based on aberrant epigenetic modifications could alleviate the senescence and dysfunction of stem cells. This review summarizes potential therapeutic targets for BMSC aging, introduces some potential approaches to alleviating BMSC aging, and analyzes its prospect in the clinical application of age-related bone diseases.

MicroRNA-602 prevents the development of inflammatory bowel diseases in a microbiota-dependent manner

Inflammatory bowel diseases (IBD) are a group of chronic disorders occurring in the intestinal tract. Previous studies demonstrated that genetics and microbiota play critical roles in the pathogenesis of IBD. Discoveries of genes that may regulate the homeostasis of gut microbiota and pathogenesis of IBD have the potential to provide new therapeutic targets for IBD treatment. The results suggested that the expression level of microRNA (miR)-602 is negatively related to the development of IBD, and that miR-602 overexpression in mice may prevent inflammation and intestinal barrier injuries in dextran sulfate sodium (DSS)-induced IBD mice. It was also found that the microbiota is important for miR-602-mediated prevention of IBD, as the inhibitory effect of miR-602 was lost when the microbiota was depleted using antibiotics. Furthermore, co-housing or adoptive transfer of microbiota from miR-602 could attenuate the pathogenesis of IBD. In addition, it was demonstrated that miR-602 could target tumor necrosis factor receptor-associated factor 6 (TRAF6) in intestinal epithelial cells. Collectively, the present results suggest that miR-602 plays a protective role in DSS-induced IBD by targeting TRAF6 in a microbiota-dependent manner.

Sonic Hedgehog Induces Mesenchymal Stromal Cell Senescence-Associated Secretory Phenotype and Chondrocyte Apoptosis in Human Osteoarthritic Cartilage

Hedgehog (HH) signaling plays a critical role in osteoarthritis (OA) pathogenesis, but the molecular mechanism remains to be elucidated. We show here that Sonic Hedgehog (SHH) gene expression is initiated in human normal cartilage stromal cells (NCSC) and increased in OA cartilage mesenchymal stromal cells (OA-MSCs) during aging. Manifesting a reciprocal cellular distribution pattern, the SHH receptors PTCH1 and SMO and transcription factors GLI2 and GLI3 are expressed by chondrocytes (OAC) in OA cartilage. SHH autocrine treatment of osteoarthritis MSC stimulates proliferation, chondrogenesis, hypertrophy, and replicative senescence with elevated SASP gene expression including IL1B, IL6, CXCL1, and CXCL8. SHH paracrine treatment of OAC suppresses COL2A1, stimulates MMP13, and induces chondrocyte apoptosis. The OA-MSC conditioned medium recapitulates the stimulatory effects of SHH on OAC catabolism and apoptosis. SHH knock-down in OA-MSC not only inhibits catabolic and senescence marker expression in OA-MSC, but also abolishes the effect of the OA-MSC conditioned medium on OAC catabolism and apoptosis. We propose that SHH is a key mediator between OA-MSC and OA chondrocytes interaction in human OA cartilage via two mechanisms: (1) SHH mediates MSC growth and aging by activating not only its proliferation and chondrogenesis, but also low-grade inflammation and replicative senescence, and (2) SHH mediates OA-MSC-induced OAC catabolism and apoptosis by creating a pro-inflammatory microenvironment favoring tissue degeneration during OA pathogenesis.

Association of sonic hedgehog signaling pathway genes IHH, BOC, RAB23a and MIR195-5p, MIR509-3-5p, MIR6738-3p with gastric cancer stage

Gastric cancer is the leading cause of cancer-related mortality worldwide. Given the importance of gastric cancer in public health, identifying biomarkers associated with disease onset is an important part of precision medicine. The hedgehog signaling pathway is considered as one of the most significant widespread pathways of intracellular signaling in the early events of embryonic development. This pathway contributes also to the maintenance of pluripotency of cancer stem cells pluripotency. In this study, we analyzed the expression levels of sonic hedgehog (Shh) signaling pathway genes IHH, BOC, RAB23a and their regulatory miRNAs including MIR-195-5p, MIR-509-3-5p, MIR-6738-3p in gastric cancer patients. In addition, the impact of infection status on the expression level of those genes and their regulatory miRNAs was investigated. One hundred samples taken from 50 gastric cancer patients (50 tumoral tissues and their adjacent non-tumoral counterparts) were included in this study. There was a significant difference in all studied genes and miRNAs in tumoral tissues in comparison with their adjacent non-tumoral counterparts. The lower expression of IHH, BOC, RAB23, miR-195-5p, and miR-6738-3p was significantly associated with more advanced cancer stage. Additionally, IHH upregulation was significantly associated with CMV infection (P < 0.001). Also, receiver operating characteristic (ROC) curve analysis indicated that mir-195 was significantly related to several clinicopathological features including tumor stage, grade, age, gender, and infection status of gastric cancer and can be considered as a potential diagnostic biomarker for gastric cancer. This study confirms the important role of Shh signaling pathway genes in gastric cancer tumorigenesis and their potential as novel molecular biomarkers and therapeutic targets.

Overview of MMP-13 as a Promising Target for the Treatment of Osteoarthritis

Osteoarthritis (OA) is a common degenerative disease characterized by the destruction of articular cartilage and chronic inflammation of surrounding tissues. Matrix metalloproteinase-13 (MMP-13) is the primary MMP involved in cartilage degradation through its particular ability to cleave type II collagen. Hence, it is an attractive target for the treatment of OA. However, the detailed molecular mechanisms of OA initiation and progression remain elusive, and, currently, there are no interventions available to restore degraded cartilage. This review fully illustrates the involvement of MMP-13 in the initiation and progression of OA through the regulation of MMP-13 activity at the molecular and epigenetic levels, as well as the strategies that have been employed against MMP-13. The aim of this review is to identify MMP-13 as an attractive target for inhibitor development in the treatment of OA.

Identification of circ_0089153/miR-608/EGFR p53 axis in ameloblastoma via MAPK signaling pathway

OBJECTIVES

This study investigated the role of circular RNAs (circRNAs) in the pathogenesis of ameloblastoma (AB), identifying potential novel targets for future targeted therapy.

MATERIALS AND METHODS

CircRNA and microRNA (miRNA) profiling in AB were built with microarrays. Six novel circRNAs were validated, circ-miRNA networks were delineated. Hsa-miR-608 was filtered over cross-comparison between database screening, miRNA microarray and validated. Circ-miRNA binding sponge was validated via luciferase reporter assay. Downstream mRNAs were screened. Regulation between miRNAs and mRNAs was confirmed in vitro. Gene interaction networks and circRNA-miRNA-mRNA interaction pathway enrichment analyses were established.

RESULTS

Six differentially expressed circRNAs were selected and validated. According to miRNAs and pathways predicted, six correlated miRNAs were selected, hsa-miR-608 was filtered and validated. The hsa_circ_0089153/hsa-miR-608 binding sponge was validated. Downstream gene interaction networks showed that EGFR and p53 had the strongest co-expression. In vitro transfection results confirmed the suppressive function of miR-608 and EGFR p53. Hsa_circ_0089153/hsa-miR-608/EGFR p53 interaction pathway enrichment analysis confirmed functions mainly enriched in MAPK and related signaling pathways regulating AB progression.

CONCLUSIONS

Six novel circRNAs were identified. Hsa_circ_0089153/hsa-miR-608 sponging was validated, hsa-miR-608 downregulated EGFR and p53, which might further regulate cell proliferation, differentiation, apoptosis, and cell cycle processes via the MAPK signaling pathway.

Lysosomal dysfunction in osteoarthritis and aged cartilage triggers apoptosis in chondrocytes through BAX mediated release of Cytochrome c

OBJECTIVE

Lysosomes are the major catabolic organelle of the cell and regulate the macromolecular and organelle turnover and programmed cell death. Here, we investigated the lysosome dysfunction in cartilage and its role in chondrocytes apoptosis and the associated mechanism.

DESIGN

Lysosomal acidification in Osteoarthritis (OA) and aged cartilage was determined by LysoSensor staining. Lysosomal function in chondrocytes was blocked by siRNA mediated depletion of Lysosomal Associated Membrane Protein 2 (LAMP2) or with lysosome inhibitors. Chondrocyte apoptosis was determined by LDH release, Caspase-3/7 activation, TUNEL and PI uptake assays. Loss of mitochondrial membrane potential (MMP/ΔΨM) and mitochondrial superoxide level was determined by JC-1 and MitoSOX staining, respectively. Colocalization of mitochondria with BCL2 associated X (BAX) and Cytochrome c was determined by immunostaining. Destabilization of medial meniscus (DMM) was performed to induce OA in mice.

RESULTS

Lysosomal acidification was found to be significantly decreased in aged mouse and human and mouse OA cartilage which also showed increased chondrocyte apoptosis. Inhibition of lysosomal function resulted in increased oxidative stress, accumulation of dysfunctional mitochondria and apoptosis in chondrocytes in monolayer and in cartilage explant cultures. Depletion of LAMP2 expression or treatment of chondrocytes with lysosomal function inhibitors increased the expression and mitochondrial translocation of BAX leading to Cytochrome c release. Lysosomal dysfunction-induced apoptosis in chondrocytes was not blocked by antioxidants MitoTempo or Diphenyleneiodonium (DPI) but was abrogated by inhibiting BAX.

CONCLUSION

Lysosomal dysfunction induce apoptosis in chondrocytes through BAX-mediated mitochondrial damage and release of Cytochrome c. Our data points to lysosomal function restoration and/or BAX inhibition in chondrocytes as a therapeutic approach for OA.

Synonymous variants in holoprosencephaly alter codon usage and impact the Sonic Hedgehog protein

Synonymous single nucleotide variants (sSNVs) have been implicated in various genetic disorders through alterations of pre-mRNA splicing, mRNA structure and miRNA regulation. However, their impact on synonymous codon usage and protein translation remains to be elucidated in clinical context. Here, we explore the functional impact of sSNVs in the Sonic Hedgehog (SHH) gene, identified in patients affected by holoprosencephaly, a congenital brain defect resulting from incomplete forebrain cleavage. We identified eight sSNVs in SHH, selectively enriched in holoprosencephaly patients as compared to healthy individuals, and systematically assessed their effect at both transcriptional and translational levels using a series of in silico and in vitro approaches. Although no evidence of impact of these sSNVs on splicing, mRNA structure or miRNA regulation was found, five sSNVs introduced significant changes in codon usage and were predicted to impact protein translation. Cell assays demonstrated that these five sSNVs are associated with a significantly reduced amount of the resulting protein, ranging from 5% to 23%. Inhibition of the proteasome rescued the protein levels for four out of five sSNVs, confirming their impact on protein stability and folding. Remarkably, we found a significant correlation between experimental values of protein reduction and computational measures of codon usage, indicating the relevance of in silico models in predicting the impact of sSNVs on translation. Considering the critical role of SHH in brain development, our findings highlight the clinical relevance of sSNVs in holoprosencephaly and underline the importance of investigating their impact on translation in human pathologies.

Impacts of Green Tea on Joint and Skeletal Muscle Health: Prospects of Translational Nutrition

Osteoarthritis and sarcopenia are two major joint and skeletal muscle diseases prevalent during aging. Osteoarthritis is a multifactorial progressive degenerative and inflammatory disorder of articular cartilage. Cartilage protection and pain management are the two most important strategies in the management of osteoarthritis. Sarcopenia, a condition of loss of muscle mass and strength, is associated with impaired neuromuscular innervation, the transition of skeletal muscle fiber type, and reduced muscle regenerative capacity. Management of sarcopenia requires addressing both skeletal muscle quantity and quality. Emerging evidence suggests that green tea catechins play an important role in maintaining healthy joints and skeletal muscle. This review covers (i) the prevalence and etiology of osteoarthritis and sarcopenia, such as excessive inflammation and oxidative stress, mitochondrial dysfunction, and reduced autophagy; (ii) the effects of green tea catechins on joint health by downregulating inflammatory signaling mediators, upregulating anabolic mediators, and modulating miRNAs expression, resulting in reduced chondrocyte death, collagen degradation, and cartilage protection; (iii) the effects of green tea catechins on skeletal muscle health via maintaining a dynamic balance between protein synthesis and degradation and boosting the synthesis of mitochondrial energy metabolism, resulting in favorable muscle homeostasis and mitigation of muscle atrophy with aging; and (iv) the current study limitations and future research directions.

Inhibition of cellular communication network factor 1 (CCN1)-driven senescence slows down cartilage inflammaging and osteoarthritis

OBJECTIVE

To explore the role of cellular communication network factor 1 (CCN1) in cartilage inflammaging and osteoarthritis (OA) pathogenesis in the isolated primary human chondrocytes in vitro, cartilage explants ex vivo, and a pre-clinical mice model.

METHODS

Recombinant human CCN1 stimulation and small interfering RNA inhibition were conducted in human chondrocytes. The RNA was extracted to quantify catabolic targets and pro-inflammatory genes and the proteins were probed with specific antibodies. IL-1β and IL-6 were monitored by ELISA. IHC was performed to evaluate important hypertrophic hallmarks and catabolic markers. The effects of Tanshinone IIA on chondrocytes were investigated in both time-dependent and dose-dependent processes. Cartilage explants were cultured in growth medium and further treated with Tanshinone IIA. The intra-articular injection was performed in 13 months old C57BL/6J mice. Safranin O and fast green staining were performed to evaluate the histological change of cartilage followed by a semi-quantitative analysis using the OARSI scoring system.

RESULTS

RNA and protein levels of CCN1 increased in an age-dependent manner compared to young donors. Increased CCN1 expression was also found in the damaged area compared to the non-lesion area which correlated with the advanced pathological change in human OA. The overexpression of CCN1 promoted chondrocytes senescence, while the down-regulation of CCN1 by small interfering RNA reduced CCN1 production and limited inflammation secretion suggesting that CCN1 was a possible novel target to intervene OA. Inhibition of CCN1 by using Tanshinone IIA could reduce SASP components in a dose- and time-dependent manner. Additionally, our data showed that Tanshinone IIA was able to preserve articular cartilage integrity, suppress CCN1 production, and inhibit SASP factors in human cartilage explants and in aged mice model.

CONCLUSION

This study showed that CCN1 signaling aggravated cartilage inflammaing and matrix degradation. Collectively, our findings showed new insight into repurposing Tanshinone IIA for slowing down OA advancement in human and mice by inhibiting the CCN1 axis.

MiR-608 Exerts Anti-inflammatory Effects by Targeting ELANE in Monocytes

miR-608 has been indicated to play an important role in the pathogenesis of various inflammation-related diseases, including sepsis and several types of cancers. However, there is little information about the underlying mechanism, especially in inflammatory cells. In this study, an hsa-miR-608-inhibition cell model was constructed in U937 cells using a lentivirus, and gene expression profiles were determined by a cDNA microarray. Altogether, 682 genes showed a difference greater than 1.2-fold, including 184 genes downregulated and 498 genes upregulated. Among these genes, one potential miR-608-target gene, ELANE, was further investigated. A positive relationship between the expression of miR-608 and that of ELANE was found both in vivo and in vitro. In addition, decreased expression of miR-608 resulted in overexpression of ELANE at both the mRNA and protein levels. Cotransfection of HEK293T cells with a miR-608 mimic inhibited reporter activity, and mutation of the miRNA seed sequences abolished the repression of reporter activity. These results suggest that miR-608 is an important posttranscriptional regulator of ELANE expression in human monocytes and may play an important role in the process of inflammation. miR-608 and neutrophil elastase may be novel targets for the diagnosis or treatment of sepsis.

Advances and challenges in studying noncoding RNA regulation of drug metabolism and development of RNA therapeutics

Accumulating evidence has demonstrated that genome-derived noncoding RNAs (ncRNAs) play important roles in modulating inter-individual variations observed in drug metabolism and disposition by controlling the expression of genes coding drug metabolizing enzymes and transporters (DMETs) and relevant nuclear receptors (NRs). With the understanding of novel ncRNA regulatory mechanisms and significance in the control of disease initiation and progression, RNA-based therapies are under active investigation that may expand the druggable targets from conventional proteins to RNAs and the genome for the treatment of human diseases. Herein we provide an overview of research strategies, approaches and their limitations in biochemical and pharmacological studies pertaining to ncRNA functions in the regulation of drug and nutrient metabolism and disposition, and discussion on the promise and challenges in developing RNA therapeutics.

Effects of the MDM-2 inhibitor Nutlin-3a on PDAC cells containing and lacking WT-TP53 on sensitivity to chemotherapy, signal transduction inhibitors and nutraceuticals

Mutations at the TP53 gene are readily detected (approximately 50-75%) in pancreatic ductal adenocarcinoma (PDAC) patients. TP53 was previously thought to be a difficult target as it is often mutated, deleted or inactivated on both chromosomes in certain cancers. In the following study, the effects of restoration of wild-type (WT) TP53 activity on the sensitivities of MIA-PaCa-2 pancreatic cancer cells to the MDM2 inhibitor nutlin-3a in combination with chemotherapy, targeted therapy, as well as, nutraceuticals were examined. Upon introduction of the WT-TP53 gene into MIA-PaCa-2 cells, which contain a TP53 gain of function (GOF) mutation, the sensitivity to the MDM2 inhibitor increased. However, effects of nutlin-3a were also observed in MIA-PaCa-2 cells lacking WT-TP53, as upon co-treatment with nutlin-3a, the sensitivity to certain inhibitors, chemotherapeutic drugs and nutraceuticals increased. Interestingly, co-treatment with nutlin-3a and certain chemotherapeutic drug such as irinotecan and oxaliplatin resulted in antagonistic effects in cells both lacking and containing WT-TP53 activity. These studies indicate the sensitizing abilities that WT-TP53 activity can have in PDAC cells which normally lack WT-TP53, as well as, the effects that the MDM2 inhibitor nutlin-3a can have in both cells containing and lacking WT-TP53 to various therapeutic agents.

Naproxen attenuates osteoarthritis progression through inhibiting the expression of prostaglandinl-endoperoxide synthase 1

OBJECTIVE

This study aims to test the effect of naproxen treatment and the biological target of naproxen for treating osteoarthritis (OA).

METHODS

Differentially expressed genes (DEGs) in OA synovial tissues and normal counterparts were analyzed by messenger RNA microarray analysis. R package (weighted gene coexpression network analysis) was used to divide DEGs into several modules and determine the hub genes in each module. The expression level of prostaglandin-endoperoxide synthase 1 ( PTGS1) in OA synovial cells and tissues was verified by a quantitative real-time polymerase chain reaction and western blot. Transwell assay evaluated the numbers of cell migration and invasion. Furthermore, Safranin O and fast green staining and hematoxylin and eosin staining were performed on joints from anterior cruciate ligament transection mice.

RESULTS

Microarray analysis determined PTGS1 was the hub gene in the black module, which was overexpressed in OA synovial cells and tissues compared with normal synovial cells. OA synovial cells transfected with sh-PTGS1 showed downregulation of PTGS1. After treatment with naproxen, the expression of PTGS1 sharply decreased in the OA group. The migration and invasion of OA synovial cells increased, whereas the cell apoptosis rate decreased when PTGS1 was overexpressed. However, the cell migration and invasion decreased, whereas cells apoptosis increased when it was treated with naproxen. Naproxen could also influence the expression level of six OA-related genes: LUBRICIN, matrix metalloproteinase 13 (MMP-13), cyclooxygenase-2 (COX-2), ACAN, COL2A1, and COL1A1.

CONCLUSION

We validated that naproxen could suppress the expression of PTGS1 in synovial cells. Moreover, naproxen could inhibit the migration/invasion ability of OA synoviocytes and promote the apoptosis rate OA synoviocytes.

Serum level of co-expressed hub miRNAs as diagnostic and prognostic biomarkers for pancreatic ductal adenocarcinoma

Background: Sensitive and specific non-invasive biomarkers are urgently needed in order to improve the survival of patients with pancreatic ductal adenocarcinoma (PDAC), which is the fourth leading cause of cancer-related death. We aim to identify serum hub miRNAs as potential diagnostic and prognostic biomarkers for PDAC.

Methods: A total of 2578 serum miRNA expression data from 88 PDAC patients and 19 healthy subjects were downloaded from the Gene Expression Omnibus database. Weighted gene co-expression network analysis (WGCNA) was constructed and significant modules were extracted from the network by WGCNA R package. Network modules and hub miRNAs closely related to PDAC were identified. The prognostic value of hub miRNAs was assessed by Kaplan-Meier overall survival analysis.

Results: Two modules strongly associated with PDAC were identified by WGCNA, which were labeled as turquoise and brown respectively. Within each module, twenty hub miRNAs were found. At the functional level, turquoise module was mainly associated with tumorigenesis pathways such as P53 and WNT signaling pathway, while the brown module was mostly related to the pathways of cancer such as RNA transport and MAPK signaling pathway. Utilizing overall survival analyses, five “real” miRNAs were able to stratify PDAC patients into low-risk and high-risk groups.

Conclusions: The association of specific Hub miRNAs with the development of pancreatic cancer was established by WGCNA analysis. Five miRNAs (mir-16-2-3p, mir-890, mir-3201, mir-602, and mir-877) were identified as potential diagnostic and prognostic biomarkers for PDAC.

Sonic Hedgehog Signaling Pathway in Endothelial Progenitor Cell Biology for Vascular Medicine

The Hedgehog (HH) signaling pathway plays an important role in embryonic and postnatal vascular development and in maintaining the homeostasis of organs. Under physiological conditions, Sonic Hedgehog (SHH), a secreted protein belonging to the HH family, regulates endothelial cell growth, promotes cell migration and stimulates the formation of new blood vessels. The present review highlights recent advances made in the field of SHH signaling in endothelial progenitor cells (EPCs). The canonical and non-canonical SHH signaling pathways in EPCs and endothelial cells (ECs) related to homeostasis, SHH signal transmission by extracellular vesicles (EVs) or exosomes containing single-strand non-coding miRNAs and impaired SHH signaling in cardiovascular diseases are discussed. As a promising therapeutic tool, the possibility of using the SHH signaling pathway for the activation of EPCs in patients suffering from cardiovascular diseases is further explored.

Exonic splice regulation imposes strong selection at synonymous sites

What proportion of coding sequence nucleotides have roles in splicing, and how strong is the selection that maintains them? Despite a large body of research into exonic splice regulatory signals, these questions have not been answered. This is because, to our knowledge, previous investigations have not explicitly disentangled the frequency of splice regulatory elements from the strength of the evolutionary constraint under which they evolve. Current data are consistent both with a scenario of weak and diffuse constraint, enveloping large swaths of sequence, as well as with well-defined pockets of strong purifying selection. In the former case, natural selection on exonic splice enhancers (ESEs) might primarily act as a slight modifier of codon usage bias. In the latter, mutations that disrupt ESEs are likely to have large fitness and, potentially, clinical effects. To distinguish between these scenarios, we used several different methods to determine the distribution of selection coefficients for new mutations within ESEs. The analyses converged to suggest that ∼15%-20% of fourfold degenerate sites are part of functional ESEs. Most of these sites are under strong evolutionary constraint. Therefore, exonic splice regulation does not simply impose a weak bias that gently nudges coding sequence evolution in a particular direction. Rather, the selection to preserve these motifs is a strong force that severely constrains the evolution of a substantial proportion of coding nucleotides. Thus synonymous mutations that disrupt ESEs should be considered as a potentially common cause of single-locus genetic disorders.

Downregulation of HS6ST2 by miR-23b-3p enhances matrix degradation through p38 MAPK pathway in osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis involving major structural changes of peripheral joints and local or systemic inflammation and in lack of therapeutic approaches because of complexity of underlying molecular basis. Our previous work showed that HS6ST2, an enzyme involved in the transfer of sulfate, is downregulated in cartilage tissues of OA patients compared with normal donors, but little is known about its regulatory mechanism. In this study, we demonstrated that the expression of HS6ST2 was lower in OA-damaged cartilage than smooth cartilage from the same patient. In chondrocytes, HS6ST2 could be targeted by miR-23b-3p, which was higher expressed in OA-damaged cartilage. Under TNF-α stimulation, the expression of HS6ST2 was found inversely correlated with the expression of miR-23b-3p. Downregulation of HS6ST2 regulated by overexpression of miR-23b-3p and siRNAs against HS6ST2 could enhance the protein level of MMP13 and aggravate the matrix degradation in chondrocytes. Increased expression of MMP13 depended on activity of p38 MAPK rather than total p38 MAPK level and was abrogated by HS6ST2 overexpression. Together, the results indicated that downregulated HS6ST2 targeted by miR-23b-3p promotes matrix degradation by activating p38 MAPK in chondrocytes and OA cartilage.

Hedgehog signaling pathway: Epigenetic regulation and role in disease and cancer development

The evolutionarily conserved Hedgehog (Hh) signaling pathway have critical roles in development and homeostasis of tissues. Under physiological conditions, Hh is controlled at different levels via stem cell maintenance and tissue regeneration. Aberrant activation of this signaling pathway may occur in a wide range of human diseases including different types of cancer. In this review we present a concise overview on the key genes composing Hh signaling pathway and provide recent advances on the molecular mechanisms that regulate Hh signaling pathway from extracellular and receptors to the cytoplasmic and nuclear machinery with a highlight on the role of microRNAs. Furthermore, we focus on critical studies demonstrating dysregulation of the Hh pathway in human disease development, and potential therapeutic implications. Finally, we introduce recent therapeutic drugs acting as Shh signaling pathway inhibitors, including those in clinical trials and preclinical studies.

Epigenetics in osteoarthritis: Potential of HDAC inhibitors as therapeutics

Osteoarthritis (OA) is the most common joint disease and the leading cause of chronic disability in middle-aged and older populations worldwide. The development of disease modifying therapy for OA is in its infancy largely because the regulatory mechanisms for the molecular effectors of OA pathogenesis are poorly understood. Recent studies identified epigenetic events as a critical regulator of molecular players involved in the induction and development of OA. Epigenetic mechanisms include DNA methylation, non-coding RNA and histone modifications. The aim of this review is to briefly highlight the recent advances in the epigenetics of cartilage and potential of HDACs (Histone deacetylases) inhibitors in the therapeutic management of OA. We summarize the recent studies utilizing HDAC inhibitors as potential therapeutics for inhibiting disease progression and preventing the cartilage destruction in OA. HDACs control normal cartilage development and homeostasis and understanding the impact of HDACs inhibitors on the disease pathogenesis is of interest because of its importance in affecting overall cartilage health and homeostasis. These findings also shed new light on cartilage disease pathophysiology and provide substantial evidence that HDACs may be potential novel therapeutic targets in OA.

A bioinformatic analysis of microRNAs role in osteoarthritis

OBJECTIVE

To evaluate the underlying function of microRNAs (miRNAs) in osteoarthritis (OA).

DESIGN

A bioinformatic analysis of miRNAs-OA studies was completed in multiple databases. All identified articles were assessed using specific inclusion and exclusion criteria (Eligible case-control studies for the present study included those which investigated miRNAs differential expression in cartilage tissues and cells of OA and controls. Abstracts, case reports, conference presentations, editorials, and expert opinions were excluded.). We performed bioinformatic analysis and assessed which miRNAs are commonly elevated or decreased in cartilage of OA, and assessed putative targets of these miRNAs using TargetScan, Database for Annotation, Visualization and Integrated Discovery (DAVID), FunRich and String.

RESULTS

Fifty seven studies were included in this study. Our current review has identified 46 differentially expressed miRNAs involved in autophagy, inflammation, chondrocyte apoptosis, chondrocyte differentiation & homeostasis, chondrocyte metabolism and degradation of the extracellular matrix (ECM). Additionally, our literature search identified a wide range of miRNAs that have been shown to be differentially expressed in OA. The function of up-regulated miRNAs primarily target nucleus, whereas the function of down-regulated miRNAs primarily target transcription.

CONCLUSIONS

Comprehensive analysis of all miRNAs studies reveals cooperation in miRNA signatures and suggests that there may be two biologically synergic classes of miRNAs that are associated with OA. This finding suggests that miRNAs may be useful as diagnostic biomarkers and/or may provide new therapeutic targets in OA. Furthermore, a better understanding of the targets of these miRNAs will accelerate biomedical discoveries and improve clinical care based on new knowledge of OA-related disease mechanisms.

Genetic Factors in Tendon Injury: A Systematic Review of the Literature

BACKGROUND

Tendon injury such as tendinopathy or rupture is common and has multiple etiologies, including both intrinsic and extrinsic factors. The genetic influence on susceptibility to tendon injury is not well understood.

PURPOSE

To analyze the published literature regarding genetic factors associated with tendon injury.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

A systematic review of published literature was performed in concordance with the Preferred Reporting Items of Systematic Reviews and Meta-analysis (PRISMA) guidelines to identify current evidence for genetic predisposition to tendon injury. PubMed, Ovid, and ScienceDirect databases were searched. Studies were included for review if they specifically addressed genetic factors and tendon injuries in humans. Reviews, animal studies, or studies evaluating the influence of posttranscription factors and modifications (eg, proteins) were excluded.

RESULTS

Overall, 460 studies were available for initial review. After application of inclusion and exclusion criteria, 11 articles were ultimately included for qualitative synthesis. Upon screening of references of these 11 articles, an additional 15 studies were included in the final review, for a total of 26 studies. The genetic factors with the strongest evidence of association with tendon injury were those involving type V collagen A1, tenascin-C, matrix metalloproteinase-3, and estrogen-related receptor beta.

CONCLUSION

The published literature is limited to relatively homogenous populations, with only level 3 and level 4 data. Additional research is needed to make further conclusions about the genetic factors involved in tendon injury.

miR-342-3p elevates osteogenic differentiation of umbilical cord mesenchymal stem cells via inhibiting Sufu in vitro

Human umbilical mesenchymal stem cells (UCMSCs) have been wildly used in tissue engineering field as a promising source because of their unlimited and noninvasive origin. To selectively induce osteogenic differentiation of UCMSCs, it's imperative to understand the regulatory molecular mechanism underlying the process of how these cells switch into osteogenic lineage path. We previously showed enhanced sonic hedgehog (Shh) signaling pathway upon osteogenic induction in mesenchymal stem cells. In this study, miRNA-seq analysis revealed substantial Shh-dependent expression of distinct miRNAs, including miR-342-3p, during ostogenesis. RT-qPCR confirmed that miR-342-3p was increased at a greater level when Shh signaling pathway was activated by N-terminal of Shh ligand compared with osteogenic induction alone, in contrast to the decreasing of suppressor-of-fused protein (Sufu). Consistently, transient overexpressing miR342-3p in UCMSCs via miR-342-3p mimics dramatically decreased Sufu, a suppressor of Gli, while osteogenic markers, including alkaline phosphate and osteocalcin, were upregulated during osteogenic induction, indicating that miR-342-3p might be involved in osteogenesis through the Shh signaling pathway. In conclusion, this study showed the potential of miR-342-3p as a therapeutic target to promote bone regeneration by modulating expression of Sufu in UCMSCs.

Knockdown of PRMT1 suppresses IL-1β-induced cartilage degradation and inflammatory responses in human chondrocytes through Gli1-mediated Hedgehog signaling pathway

Osteoarthritis (OA) is characterized by articular cartilage degradation and joint inflammation. The purpose of the present study is to elucidate the role of the specific function of PRMT1 in chondrocytes and its association with the pathophysiology of OA. We observed that the expression of PRMT1 was apparently upregulated in OA cartilage, as well as in chondrocytes stimulated with IL-1β. Additionally, knockdown of PRMT1 suppressed interleukin 1 beta (IL-1β)-induced extracellular matrix (ECM) metabolic imbalance by regulating the expression of MMP-13, ADAMTS-5, COL2A1, and ACAN. Furthermore, silencing of PRMT1 dramatically declined the production of prostaglandin E2 (PGE2) and nitric oxide as well as the level of pro-inflammatory cytokine IL-6 and TNF-α. Mechanistic analyses further revealed that IL-1β-induced activation of the Hedgehog/Gli-1 signaling is suppressed upon PRMT1 knockdown. However, the effects of inhibition of PRMT1-mediated IL-1β-induced cartilage matrix degradation and inflammatory response in OA chondrocytes were obviously abolished by Hedgehog agonist Purmorphamine (Pur). Our data collectively suggest that silencing of PRMT1 exerts anti-catabolic and anti-inflammatory effects on IL-1β-induced chondrocytes via suppressing the Gli-1 mediated Hedgehog signaling pathway, indicating that PRMT1 plays a critical role in OA development and serves as a promising therapeutic target for OA.

MicroRNA miR-214 inhibits snakehead vesiculovirus replication by targeting the coding regions of viral N and P

Snakeheadvesiculovirus (SHVV), a new member of the family Rhabdoviridae, has caused enormous economic losses in snakehead fish culture during the past years in China; however, little is known about the molecular mechanisms of its pathogenicity. MicroRNAs (miRNAs) are small non-coding RNAs that play important roles in virus infection. In this study, we identified that SHVV infection downregulated miR-214 in striped snakehead (SSN-1) cells in a time- and dose-dependent manner. Notably, transfecting SSN-1 cells with miR-214 mimic significantly inhibitedSHVV replication, whereas miR-214 inhibitor promoted it, suggesting that miR-214 acted as a negative regulator of SHVV replication. Our study further demonstrated that N and P of SHVV were the target genes of miR-214. Over-expression of P, but not N, inhibited IFN-α production in SHVV-infected cells, which could be restored by over-expression of miR-214. Taken together, these results suggest that miR-214 is downregulated during SHVV infection, and the downregulated miR-214 in turn increased N and P expression and decreased IFN-α production, thus facilitating SHVV replication. This study provides a better understanding of the molecular mechanisms on the pathogenesis of SHVV and a potential antiviral strategy against SHVV infection.

MicroRNA-29a Counteracts Synovitis in Knee Osteoarthritis Pathogenesis by Targeting VEGF

Synovitis contributes to the development of osteoarthritis (OA) of the knee. MicroRNAs regulate joint microenvironment homeostasis and deterioration. This study was undertaken to characterize the actions of microRNA-29a (miR-29a) to synovial remodeling in OA joints. Synovial specimens isolated from patients with end-stage OA knees showed abundant fibrotic matrix and vessel histopathology concomitant with weak miR-29a expression. In vitro, miR-29a knockdown caused synovial fibroblasts to exhibit high expressions of collagen III, TGF-β1, MMP9, MMP13, and ADAMTS5, whereas miR-29a overexpression diminished these joint-deleterious factors. In collagenase-mediated OA pathogenesis, miR-29a-overexpressing transgenic mice showed minor responses to hyperplasia, macrophage infiltration, fibrosis, hyperangiogenesis, and VEGF expression in synovial lesions. These effects mitigated articular cartilage loss and gait aberrance of injured joints. Intra-articular administration of miR-29a precursor lessened the collagenase aggravation of excessive synovial remodeling reactions and thereby sustained joint tissue integrity. miR-29a lowered VEGF production and angiogenic activities in synovial fibroblasts through targeting the 3′-UTR of VEGF. Taken together, miR-29a deficiency exacerbated synovitis pathogenesis in the end-stage OA knees. miR-29a signaling fends off excessive synovial angiogenesis and fibrosis, which delays joint destruction. This study sheds new light on the protective effects against synovial deterioration and the therapeutic advantage of miR-29a in OA knees.

MicroRNA hsa-miR-370-3p suppresses the expression and induction of CYP2D6 by facilitating mRNA degradation

Cytochrome P450 2D6 (CYP2D6) participates in the metabolism of approximately 20-25% of prescribed drugs. Genetic polymorphisms influence the expression and/or activity of CYP2D6, and inter-individual differences in drug activation and elimination caused by CYP2D6 genetic variants were reported. However, little is known about the potential modulation of CYP2D6 expression by microRNAs (miRNAs). In the current study, by using in silico prediction of the stabilities of miRNA/mRNA complexes, we screened 38 miRNA candidates that may interact with the transcript of CYP2D6. An inverse correlation between the expression of miRNA hsa-miR-370-3p and the expression of CYP2D6 was observed in human liver tissue samples. Electrophoretic mobility shift assays confirmed that hsa-miR-370-3p was able to directly bind to its cognate target within the coding region of the CYP2D6 transcript. The transfection of hsa-miR-370-3p mimics into the HepG2^CYP2D6 cell line, a genetically modified cell line that overexpresses exogenous CYP2D6, was able to suppress the expression of CYP2D6 significantly at both mRNA and protein levels. The transfection of hsa-miR-370-3p mimics was also able to inhibit endogenous mRNA expression and/or protein production of CYP2D6 in HepaRG cells. Furthermore, in HepaRG, HepG2, and Huh7 cells, dexamethasone-induced expression of CYP2D6 was inhibited by hsa-miR-370-3p mimics. To investigate whether the miRNA mediated suppression is caused by inhibiting protein translation or promoting mRNA degradation, an actinomycin D assay was used to measure the stability of CYP2D6 transcripts. The results indicated that hsa-miR-370-3p mimics facilitated significantly the degradation of CYP2D6 mRNA. In addition, proteomics analyses of proteins isolated from the miRNA/mRNA/protein complex suggested that a group of multifunctional proteins facilitated the interaction between hsa-miR-370-3p and CYP2D6, thereby promoting mRNA degradation.

Altered MicroRNA Expression Is Responsible for the Pro-Osteogenic Phenotype of Interstitial Cells in Calcified Human Aortic Valves

BACKGROUND

The transition of aortic valve interstitial cells (AVICs) to myofibroblastic and osteoblast-like phenotypes plays a critical role in calcific aortic valve disease progression. Several microRNAs (miRs) are implicated in stem cell differentiation into osteoblast. We hypothesized that an epigenetic mechanism regulates valvular pro-osteogenic activity. This study examined miR profile in AVICs of calcified valves and identified miRs responsible for AVIC phenotypic transition.

METHODS AND RESULTS

AVICs were isolated from normal and diseased valves. The miR microarray analysis revealed 14 upregulated and 12 downregulated miRs in diseased AVICs. Increased miR-486 and decreased miR-204 levels were associated with higher levels of myofibroblastic biomarker α-smooth muscle actin and osteoblastic biomarkers runt-related transcription factor 2 (Runx2) and osterix (Osx). Cotransfection of miR-486 antagomir and miR-204 mimic in diseased AVICs reduced their ability to express Runx2 and Osx. The miR-486 mimic upregulated α-smooth muscle actin expression in normal AVICs through the protein kinase B pathway and moderately elevated Runx2 and Osx levels. Knockdown of α-smooth muscle actin attenuated Runx2 and Osx expression induced by miR-486. The miR-486 mimic and miR-204 antagomir synergistically promoted Runx2 and Osx expression and calcium deposition in normal AVICs and normal aortic valve tissue.

CONCLUSIONS

In AVICs of calcified valves, increased levels of miR-486 induce myofibroblastic transition to upregulate Runx2 and Osx expression and synergize with miR-204 deficiency to elevate cellular and valvular pro-osteogenic activity. These novel findings indicate that modulation of the epigenetic mechanism underlying valvular pro-osteogenic activity has therapeutic potential for prevention of calcific aortic valve disease progression.

A systematic evaluation of microRNAs in regulating human hepatic CYP2E1

Cytochrome P450 2E1 (CYP2E1) is an important drug metabolizing enzyme for processing numerous xenobiotics in the liver, including acetaminophen and ethanol. Previous studies have shown that microRNAs (miRNAs) can suppress CYP2E1 expression by binding to the 3'-untranslated region (3'-UTR) of its transcript. However, a systematic analysis of CYP2E1 regulation by miRNAs has not been described. Here, we applied in silico, in vivo, and in vitro approaches to investigate miRNAs involved in the regulation of CYP2E1. Initially, potential miRNA binding sites in the CYP2E1 mRNA transcript were identified and screened using in silico methods. Next, inverse correlations were found in human liver samples between the expression of CYP2E1 mRNA and the levels of two miRNA species, hsa-miR-214-3p and hsa-miR-942-5p. In a HepG2-derived CYP2E1 over-expression cell model, hsa-miR-214-3p exhibited strong suppression of CYP2E1 expression by targeting the coding region of its mRNA transcript, but hsa-miR-942-5p did not inhibit CYP2E1 levels. Electrophoretic mobility shift assays confirmed that hsa-miR-214-3p recruited other cellular protein factors to form stable complexes with specific sequences present in the CYP2E1 mRNA open reading frame. Transfection of HepaRG cells with hsa-miR-214-3p mimics inhibited expression of the endogenous CYP2E1 gene. Further, hsa-miR-214-3p mimics partially blocked ethanol-dependent increases in CYP2E1 mRNA and protein levels in HepG2 cells and they reduced the release of alanine aminotransferase from CYP2E1-overexpressing HepG2 cells exposed to acetaminophen. These results substantiate the suppressing effect of hsa-miR-214-3p on CYP2E1 expression.

Epigallocatechin-3-O-gallate modulates global microRNA expression in interleukin-1β-stimulated human osteoarthritis chondrocytes: potential role of EGCG on negative co-regulation of microRNA-140-3p and ADAMTS5

PURPOSE

MicroRNAs (miRNAs) are short, non-coding RNAs involved in almost all cellular processes. Epigallocatechin-3-O-gallate (EGCG) is a green tea polyphenol and is known to exert anti-arthritic effects by inhibiting genes associated with osteoarthritis (OA). This study was undertaken to investigate the global effect of EGCG on interleukin-1β (IL-1β)-induced expression of miRNAs in human chondrocytes.

METHODS

Human chondrocytes were derived from OA cartilage and then treated with EGCG and IL-1β. Human miRNA microarray technology was used to determine the expression profile of 1347 miRNAs. Microarray results were verified by taqman assays and transfection of chondrocytes with miRNA inhibitors.

RESULTS

Out of 1347 miRNAs, EGCG up-regulated expression of 19 miRNAs and down-regulated expression of 17 miRNAs, whereas expression of 1311 miRNAs remains unchanged in IL-1β-stimulated human OA chondrocytes. Bioinformatics approach showed that 3`UTR of ADAMTS5 mRNA contains the 'seed-matched-sequence' for hsa-miR-140-3p. IL-1β-induced expression of ADAMTS5 correlated with down-regulation of hsa-miR-140-3p. Importantly, EGCG inhibited IL-1β-induced ADAMTS5 expression and up-regulated the expression of hsa-miR-140-3p. This EGCG-induced co-regulation between ADAMTS5 and hsa-miR-140-3p becomes reversed in OA chondrocytes transfected with anti-miR-140-3p.

CONCLUSIONS

This study provides an important insight into the molecular basis of the reported anti-arthritic effects of EGCG. Our data indicate that the potential of EGCG in OA chondrocytes may be related to its ability to globally inhibit inflammatory response via modulation of miRNAs expressions.

Histone deacetylase inhibitor vorinostat (SAHA, MK0683) perturb miR-9-MCPIP1 axis to block IL-1β-induced IL-6 expression in human OA chondrocytes

AIM OF THE STUDY

High levels of IL-6 are believed to contribute to osteoarthritis (OA) pathogenesis. The expression of IL-6 is regulated post-transcriptionally by the miR-9-MCPIP-1 axis in chondrocytes. Vorinostat (SAHA) inhibits the IL-6 expression in OA chondrocytes. We investigated whether SAHA suppresses the expression of IL-6 by perturbing the miR-9-MCPIP1 axis in OA chondrocytes under pathological conditions.

MATERIALS AND METHODS

OA chondrocytes were isolated by enzymatic digestion and treated with IL-1β in the absence or presence of SAHA. Genes and protein expression levels were determined by TaqMan assays and Western blotting, respectively. Secreted IL-6 was quantified by enzyme linked immunosorbent assay (ELISA). MCPIP1 promoter deletion mutants were generated by polymerase chain reaction (PCR). Promoter recruitment of transcription factors was determined by ChIP. Nuclear run-on was employed to measure the ongoing transcription. siRNA-mediated knockdown of the CEBPα expression was employed for loss of function studies.

RESULTS

Expression of MCPIP1 was high in SAHA treated OA chondrocytes but expression of IL-6 mRNAs and secreted IL-6 were reduced by ~70%. SAHA suppressed the expression of miR-9 but enhanced the activity of the MCPIP1 promoter localized to a 156bp region which also harbors the binding site for CEBPα. Treatment with SAHA enhanced the recruitment of CEBPα to the MCPIP1 promoter. Ectopically expressed CEBPα enhanced the promoter activity and the expression of MCPIP1 while siRNA-mediated knockdown of CEBPα inhibited the expression of MCPIP1.

CONCLUSIONS

Taken together our data indicate that SAHA-mediated suppression of the IL-6 expression is achieved through increased recruitment of CEBPα to the MCPIP1 promoter and by relieving the miR-9-mediated inhibition of MCPIP1 expression in OA chondrocytes.

MicroRNAs in Oncogenesis and Tumor Suppression

MicroRNAs (MiRNAs) have emerged in the last 15 years as central players in the biology of cancer. Increasing lines of evidence have supported their regulatory role in the expression of both oncogenes and tumor-suppressor genes, progressively clarifying which genes are modulated by specific MiRNAs dysregulated in cancer. Intriguingly, a "target-specific" understanding of MiRNA function in oncology has been replaced by a more "pathway-specific" vision of their involvement in cancer biology. This work provides a state-of-the-art knowledge of the role of MiRNAs in the most frequently altered signaling pathways in cancer cells and provides an updated overview on some of the most relevant findings trying to decode the complex molecular mechanisms of cancer.

Alcohol Use During Pregnancy is Associated with Specific Alterations in MicroRNA Levels in Maternal Serum

Background

Given the challenges of confirming prenatal alcohol exposure (PAE) during pregnancy using currently established biomarkers of alcohol consumption, we examined whether serum microRNAs (miRNAs) may serve as stable biomarkers for PAE. Alterations in the levels of specific circulating miRNAs have been associated with various disease states and in animal models of fetal alcohol spectrum disorder.

Methods

Pregnant women in this prospective study were recruited from substance abuse and general maternity clinics affiliated with the University of New Mexico. Serum was collected at the time of admission for delivery from 14 subjects who reported ≥1 binge‐drinking episode or ≥3 drinks/wk during pregnancy and 16 subjects who reported abstinence during pregnancy and tested negative for 5 ethanol biomarkers. Total RNA was isolated from serum and used for microarray analysis.

Results

False discovery rate‐corrected analyses of covariance revealed that 55 miRNAs were significantly altered between the 2 groups. Hierarchical clustering using only the significantly altered miRNAs grouped samples into alcohol‐consuming and non‐alcohol‐consuming individuals. Discriminant analysis then identified miRs‐122*, ‐126, ‐216b, ‐221*, ‐3119, ‐3942‐5p, ‐4704‐3p, ‐4743, ‐514‐5p, and ‐602 as the top 10 discriminators between the 2 groups. Ingenuity Pathway Analysis of putative miRNA targets illustrated that miRNAs identified in this study are involved in biological pathways that mediate the effects of alcohol, such as brain‐derived neurotrophic factor, ERK1/2, and PI3K/AKT signaling.

Conclusions

This is the first report of alterations in serum miRNA expression that are associated with alcohol use during human pregnancy. These results suggest that serum miRNAs could be useful as biomarkers of alcohol exposure.

The Role of miRNAs in Common Inflammatory Arthropathies: Osteoarthritis and Gouty Arthritis

MicroRNAs (miRNAs) are small, non-coding RNA species that are highly evolutionarily conserved, from higher invertebrates to man. Up to 1000 miRNAs have been identified in human cells thus far, where they are key regulators of the expression of numerous targets at the post-transcriptional level. They are implicated in various processes, including cell differentiation, metabolism, and inflammation. An expanding list of miRNAs is known to be involved in the pathogenesis of common, non-autoimmune inflammatory diseases. Interestingly, osteoarthritis (OA) is now being conceptualized as a metabolic disease, as there is a correlation among hyperuricemia and metabolic syndrome (MetS). Experimental evidence suggests that metabolic deregulation is a commonality between these different pathological entities, and that miRNAs are key players in the modulation of metabolic routes. In light of these findings, this review discusses the role of miRNAs in OA and gouty arthritis, as well as the possible therapeutic targetability of miRNAs in these diseases.

Histone Deacetylase Inhibitor Vorinostat (SAHA) Suppresses IL-1β-Induced Matrix Metallopeptidase-13 Expression by Inhibiting IL-6 in Osteoarthritis Chondrocyte

Osteoarthritis (OA) is the most common whole-joint disease and is characterized by progressive loss of the cartilage matrix. Matrix metallopeptidase-13 (MMP-13) is a highly active and an abundantly expressed protease in OA cartilage and chondrocytes and degrades type II collagen and proteoglycans. We investigated the mechanism of MMP-13 suppression by histone deacetylase inhibitor vorinostat (SAHA). OA chondrocytes were obtained from knee cartilage after enzymatic digestion and treated with IL-1β in the absence or presence of various histone deacetylase inhibitors. Gene expression was quantified using quantitative RT-PCR. Protein expression and chromatin modifications were determined by Western immunoblotting using specific antibodies. The effect of IL-6 on the expression of MMP-13 was determined by treating chondrocytes with recombinant IL-6 or by IL6 knockdown using IL6-specific siRNA. We found that SAHA is a potent suppressor of IL-1β-induced MMP-13, tumor necrosis factor-α, and other catabolic marker expression in OA chondrocytes. Interestingly, SAHA rescued the COL2A1 and ACAN expression in OA chondrocytes that was down-regulated by IL-1β. Of importance is our finding that IL-6-stimulated MMP-13 expression was independent of IL-1β stimulation and was blocked by SAHA, suggesting that SAHA inhibits IL-6 signaling in OA chondrocytes. Taken together, our results suggest that SAHA could be used as a therapeutic agent for the management of OA.

MicroRNA-17 Suppresses TNF-α Signaling by Interfering with TRAF2 and cIAP2 Association in Rheumatoid Arthritis Synovial Fibroblasts

TNF-α is a major cytokine implicated in rheumatoid arthritis (RA), and its expression is regulated at the transcriptional and posttranscriptional levels. However, the impact of changes in microRNA expression on posttranslational processes involved in TNF-α signaling networks is not well defined in RA. In this study, we evaluated the effect of miR-17, a member of the miR-17-92 cluster, on the TNF-α signaling pathway in human RA synovial fibroblasts (SFs). We demonstrated that miR-17 expression was significantly low in RA serum, SFs, and synovial tissues, as well as in the serum and joints of adjuvant-induced arthritis rats. RNA-sequencing analysis showed modulation of 664 genes by pre-miR-17 in human RA SFs. Ingenuity pathway analysis of RNA-sequencing data identified the ubiquitin proteasome system in the TNF-α signaling pathway as a primary target of miR-17. Western blot analysis confirmed the reduction in TRAF2, cIAP1, cIAP2, USP2, and PSMD13 expression by miR-17 in TNF-α-stimulated RA SFs. Immunoprecipitation assays showed that miR-17 restoration increased the K48-linked polyubiquitination of TRAF2, cIAP1, and cIAP2 in TNF-α-stimulated RA SFs. Thus, destabilization of TRAF2 by miR-17 reduced the ability of TRAF2 to associate with cIAP2, resulting in the downregulation of TNF-α-induced NF-κBp65, c-Jun, and STAT3 nuclear translocation and the production of IL-6, IL-8, MMP-1, and MMP-13 in human RA SFs. In conclusion, this study provides evidence for the role of miR-17 as a negative regulator of TNF-α signaling by modulating the protein ubiquitin processes in RA SFs.

The Role of MicroRNAs and Their Targets in Osteoarthritis

Micro ribonucleic acid (microRNA) regulation and expression has become an emerging field in determining the mechanisms regulating a variety of inflammation-mediated diseases. Several studies have focused on specific microRNAs that are differentially expressed in cases of osteoarthritis. Furthermore, several targets of these miRNAs important in disease progression have also been identified. In this review, we focus on microRNA biogenesis, regulation, detection, and quantification with an emphasis on cellular localization and how these concepts may be linked to disease processes such as osteoarthritis. Next, we review the relationships of specific microRNAs to certain features and risk factors associated with osteoarthritis such as inflammation, obesity, autophagy, and cartilage homeostasis. We also identify certain microRNAs that are differentially expressed in osteoarthritis but have unidentified targets and functions in the disease state. Lastly, we identify the potential use of microRNAs for therapeutic purposes and also mention certain remedies that regulate microRNA expression.

miR-219 regulates neural progenitors by dampening apical Par protein-dependent Hedgehog signaling

The transition of dividing neuroepithelial progenitors to differentiated neurons and glia is essential for the formation of a functional nervous system. Sonic hedgehog (Shh) is a mitogen for spinal cord progenitors, but how cells become insensitive to the proliferative effects of Shh is not well understood. Because Shh reception occurs at primary cilia, which are positioned within the apical membrane of neuroepithelial progenitors, we hypothesized that loss of apical characteristics reduces the Shh signaling response, causing cell cycle exit and differentiation. We tested this hypothesis using genetic and pharmacological manipulation, gene expression analysis and time-lapse imaging of zebrafish embryos. Blocking the function of miR-219, a microRNA that downregulates apical Par polarity proteins and promotes progenitor differentiation, elevated Shh signaling. Inhibition of Shh signaling reversed the effects of miR-219 depletion and forced expression of Shh phenocopied miR-219 deficiency. Time-lapse imaging revealed that knockdown of miR-219 function accelerates the growth of primary cilia, revealing a possible mechanistic link between miR-219-mediated regulation of apical Par proteins and Shh signaling. Thus, miR-219 appears to decrease progenitor cell sensitivity to Shh signaling, thereby driving these cells towards differentiation.

Intensified vmPFC surveillance over PTSS under perturbed microRNA-608/AChE interaction

Trauma causes variable risk of posttraumatic stress symptoms (PTSS) owing to yet-unknown genome-neuronal interactions. Here, we report co-intensified amygdala and ventromedial prefrontal cortex (vmPFC) emotional responses that may overcome PTSS in individuals with the single-nucleotide polymorphism (SNP) rs17228616 in the acetylcholinesterase (AChE) gene. We have recently shown that in individuals with the minor rs17228616 allele, this SNP interrupts AChE suppression by microRNA (miRNA)-608, leading to cortical elevation of brain AChE and reduced cortisol and the miRNA-608 target GABAergic modulator CDC42, all stress-associated. To examine whether this SNP has effects on PTSS and threat-related brain circuits, we exposed 76 healthy Israel Defense Forces soldiers who experienced chronic military stress to a functional magnetic resonance imaging task of emotional and neutral visual stimuli. Minor allele individuals predictably reacted to emotional stimuli by hyperactivated amygdala, a hallmark of PTSS and a predisposing factor of posttraumatic stress disorder (PTSD). Despite this, minor allele individuals showed no difference in PTSS levels. Mediation analyses indicated that the potentiated amygdala reactivity in minor allele soldiers promoted enhanced vmPFC recruitment that was associated with their limited PTSS. Furthermore, we found interrelated expression levels of several miRNA-608 targets including CD44, CDC42 and interleukin 6 in human amygdala samples (N=7). Our findings suggest that miRNA-608/AChE interaction is involved in the threat circuitry and PTSS and support a model where greater vmPFC regulatory activity compensates for amygdala hyperactivation in minor allele individuals to neutralize their PTSS susceptibility.

The Role of miRNAs in Cartilage Homeostasis

Osteoarthritis (OA) is an age-related disease with poorly understood pathogenesis. Recent studies have demonstrated that miRNA might play a key role in OA initiation and development. We reviewed recent publications and elucidated the connection between miRNA and OA cartilage anabolic and catabolic signals, including four signaling pathways: TGF-β/Smads and BMPs signaling, associated with cartilage anabolism; and MAPK and NF-KB signaling, associated with cartilage catabolism. We also explored the relationships with MMP, ADAMTS and NOS (NitricOxide Synthases) families, as well as with the catabolic cytokines IL-1 and TNF-α. The potential role of miRNAs in biological processes such as cartilage degeneration, chondrocyte proliferation, and differentiation is discussed. Collective evidence indicates that miRNAs play a critical role in cartilage degeneration. These findings will aid in understanding the molecular network that governs articular cartilage homeostasis and in to elucidate the role of miRNA in the pathogenesis of OA.

MicroRNAs: exploring new horizons in osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a common disease worldwide leading to significant morbidity. The underlying disease process is multifactorial however there is increasing focus on molecular mechanisms. MicroRNAs are small non-coding segments of RNA that have important regulatory functions at a cellular level. These molecules are readily detectable in human tissues and circulation. They are increasingly recognised as having a major role in many disease processes - including malignancy and inflammatory processes.

OBJECTIVE

This review paper aims to provide a comprehensive update on the evidence for miRNA roles in OA.

DESIGN

A comprehensive literature search was performed using key medical subject headings (MeSH) terms 'microRNA' and 'osteoarthritis'.

RESULTS

Several miRNAs have been identified as having aberrant expression levels in OA. Some of these include miR-9, miR-27, miR-34a, miR-140, miR-146a, miR-558 and miR-602. Many of the dysregulated miRNAs have been shown to regulate expression of inflammatory pathways such as interleukin-mediated or matrix metalloproteinase-13 (MMP-13)-mediated degradation of the articular cartilage extracellular matrix (ECM). MiRNAs may also play a role in pain pathways and hence expression of clinical symptoms.

CONCLUSIONS

Recent evidence has shown that miRNAs in the circulation may reflect underlying disease states and hence serve as potential markers for disease activity. These findings may represent possible future therapeutic applications in the management of OA.

MicroRNA-30a promotes extracellular matrix degradation in articular cartilage via downregulation of Sox9

OBJECTIVES

Sox9 has recently been reported to be a key mediator during cartilage degradation in osteoarthritis (OA). Our aim was to clarify the role of microRNA-30a (miR-30a) and its target gene Sox9 in regulation of extracellular matrix (ECM) degradation in OA.

MATERIALS AND METHODS

Expression of miR-30a in cartilage tissues and in primary chondrocytes from healthy and OA donors, was determined by real-time PCR, and levels of Sox9 mRNA and protein were analyzed by real-time PCR and western blotting, respectively. Subsequently, the target of miR-30a was predicted by bioinformatics and confirmed using a luciferase assay. Expression of ECM-related genes was determined by tissue-specific staining, immunofluorescence, real-time PCR, and western blotting. The role of miR-30a in OA was examined in vivo using a collagenase-induced OA rat model.

RESULTS

miR-30a was significantly upregulated and Sox9 was downregulated in primary chondrocytes from cartilage taken from OA donors compared to healthy controls. We showed that miR-30a specifically bound to the 3' UTR of Sox9, and overexpression of miR-30a downregulated expression levels of Sox9, proteoglycan aggrecan, and Col II compared to those induced by small interfering RNA transfection to knockdown Sox9. miR-30a inhibition reversed the effects of ECM degradation in vitro and in vivo.

CONCLUSIONS

miR-30a acts as a virulence MRA in OA, promoting ECM degradation by targeting Sox9 and by modulating activity of its downstream effectors Col II and proteoglycan aggrecan.

miR-105/Runx2 axis mediates FGF2-induced ADAMTS expression in osteoarthritis cartilage

Fibroblast growth factor 2 (FGF2) plays an important role in the development of osteoarthritis (OA) through the regulation of cartilage degradation. However, the molecular mechanism underlying FGF2-induced OA is poorly characterized. MicroRNAs (miRNAs) maintain cartilage homeostasis. To examine whether FGF2 regulates OA through the modulation of miRNA, we screened potential miRNA molecules that could be regulated through FGF2 using microarray analysis. The results showed that microRNA-105 (miR-105) was significantly downregulated in chondrocytes stimulated with FGF2. Runt-related transcription factor 2 (Runx2), a key transcription factor involved in OA, has been identified as a novel potential target of miR-105. FGF2 suppressed miR-105 expression through the recruitment of the subunit of the nuclear factor kappa B transcription complex p65 to the miR-105 promoter. The knockdown of Runx2 mimicked the effect of miR-105 and abolished the ability of miR-105 to regulate the expression of a disintegrin-like and metalloproteinase with thrombospondin 4 (ADAMTS4), ADAMTS5, ADAMTS7 and ADAMTS12, both of which are responsible for the degradation of collagen 2A1 (COL2A1) and aggrecan (ACAN). miR-105 is also required for FGF2/p65-induced Runx2 activation and ADAMTS expression. Moreover, miR-105 expression was downregulated in OA patients and inversely correlated with the expression of Runx2, ADAMTS7 and ADAMTS12, which were upregulated in OA patients. These data highlight that the FGF2/p65/miR-105/Runx2/ADAMTS axis might play an important role in OA pathogenesis and that miR-105 might be a potential diagnostic target and useful strategy for OA treatment.

KEY MESSAGE

Runx2 was identified as a novel direct target of miR-105. FGF2 inhibits miR-105 transcription through recruitment of p65 to miR-105 promoter. p65/miR-105 is essential for FGF2-mediated Runx2 and ADAMTS upregulation. miR-105 is downregulated in OA and inversely correlated with Runx2 expression.

MicroRNA-9 promotion of interleukin-6 expression by inhibiting monocyte chemoattractant protein-induced protein 1 expression in interleukin-1β-stimulated human chondrocytes

OBJECTIVE

Enhanced expression of interleukin-6 (IL-6) plays an important role in the pathogenesis of osteoarthritis (OA). Monocyte chemoattractant protein-induced protein 1 (MCPIP-1) is a novel posttranscriptional regulator of IL-6 expression and is targeted by microRNA-9 (miR-9). We investigated the expression of MCPIP-1 in OA cartilage and explored whether targeting of MCPIP-1 by miR-9 contributes to enhanced IL-6 expression in OA.

METHODS

Gene and protein expression in IL-1β-stimulated human OA chondrocytes/cartilage was determined by TaqMan assay and immunoblotting, respectively. Messenger RNA (mRNA) for MCPIP-1 and IL-6 expression at the single-cell level was analyzed using RNAscope. MCPIP-1 protein interaction with IL-6 mRNA was investigated using RNA immunoprecipitation. Transient transfections were used for the small interfering RNA (siRNA)-mediated knockdown and overexpression of MCPIP-1, its RNase-defective mutant miR-9, or antagomir. The role of signaling pathways was evaluated using small-molecule inhibitors. Binding of miR-9 with the "seed sequence" in the 3'-untranslated region of MCPIP-1 mRNA was investigated using a luciferase reporter assay.

RESULTS

MCPIP-1 mRNA expression was low, but expression of miR-9 and IL-6 was high, in damaged OA cartilage. In IL-1β-stimulated OA chondrocytes, the expression of miR-9 and MCPIP-1 was mutually exclusive, and increased expression of miR-9 correlated with reduced MCPIP-1 expression and enhanced IL-6 expression. MCPIP-1 protein directly binds with IL-6 mRNA, and overexpression of wild-type MCPIP-1 destabilized the IL-6 mRNA. MCPIP-1 expression was altered by overexpression or inhibition of miR-9. Transfection with miR-9 mimics inhibited the reporter activity, and mutation of the "seed sequence" abolished the repression of reporter activity.

CONCLUSION

These findings implicate miR-9-mediated suppression of MCPIP-1 in the pathogenesis of OA via up-regulation of IL-6 expression in IL-1β-stimulated human OA chondrocytes.