MicroRNA in 2012: Biotherapeutic potential of microRNAs in rheumatic diseases

Mesenchymal stem cell-derived exosome alleviates sepsis- associated acute liver injury by suppressing MALAT1 through microRNA-26a-5p: an innovative immunopharmacological intervention and therapeutic approach for sepsis

Background

Sepsis is a syndrome with the disturbed host response to severe infection and is a major health problem worldwide. As the front line of infection defense and drug metabolism, the liver is vulnerable to infection- or drug-induced injury. Acute liver injury (ALI) is thus common in patients with sepsis and is significantly associated with poor prognosis. However, there are still few targeted drugs for the treatment of this syndrome in clinics. Recent studies have reported that mesenchymal stem cells (MSCs) show potential for the treatment of various diseases, while the molecular mechanisms remain incompletely characterized.

Aims and Methods

Herein, we used cecal ligation puncture (CLP) and lipopolysaccharide (LPS) plus D-galactosamine (D-gal) as sepsis-induced ALI models to investigate the roles and mechanisms of mesenchymal stem cells (MSCs) in the treatment of ALI in sepsis.

Results

We found that either MSCs or MSC-derived exosome significantly attenuated ALI and consequent death in sepsis. miR-26a-5p, a microRNA downregulated in septic mice, was replenished by MSC-derived exosome. Replenishment of miR-26a-5p protected against hepatocyte death and liver injury caused by sepsis through targeting Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), a long non-coding RNA highly presented in hepatocyte and liver under sepsis and inhibiting anti-oxidant system.

Conclusion

Taken together, the results of the current study revealed the beneficial effects of MSC, exosome or miR-26a-5p on ALI, and determined the potential mechanisms of ALI induced by sepsis. MALAT1 would be a novel target for drug development in the treatment of this syndrome.

MicroRNA-9 mediated the protective effect of ferulic acid on hypoxic-ischemic brain damage in neonatal rats

Neonatal hypoxic-ischemic brain damage (HIBD) is prone to cognitive and memory impairments, and there is no effective clinical treatment until now. Ferulic acid (FA) is found within members of the genus Angelica, reportedly shows protective effects on neuronal damage. However, the protective effects of FA on HIBD remains unclear. In this study, using the Morris water maze task, we herein found that the impairment of spatial memory formation in adult rats exposed to HIBD was significantly reversed by FA treatment and the administration of LNA-miR-9. The expression of miRNA-9 was detected by RT-PCR analyses, and the results shown that miRNA-9 was significantly increased in the hippocampus of neonatal rats following HIBD and in the PC12 cells following hypoxic-ischemic injury, while FA and LNA-miR-9 both inhibited the expression of miRNA-9, suggesting that the therapeutic effect of FA was mainly attributed to the inhibition of miRNA-9 expression. Indeed, the silencing of miR-9 by LNA-miR-9 or FA similarly attenuated neuronal damage and cerebral atrophy in the rat hippocampus after HIBD, which was consistent with the restored expression levels of brain-derived neurotrophic factor (BDNF). Therefore, our findings indicate that FA treatment may protect against neuronal death through the inhibition of miRNA-9 induction in the rat hippocampus following hypoxic-ischemic damage.

miR-26a-5p protects against myocardial ischemia/reperfusion injury by regulating the PTEN/PI3K/AKT signaling pathway

Reperfusion strategies in acute myocardial infarction (AMI) can cause a series of additional clinical damage, defined as myocardial ischemia/reperfusion (I/R) injury, and thus there is a need for effective therapeutic methods to attenuate I/R injury. miR-26a-5p has been proven to be an essential regulator for biological processes in different cell types. Nevertheless, the role of miR-26a-5p in myocardial I/R injury has not yet been reported. We established an I/R injury model in vitro and in vivo. In vitro, we used cardiomyocytes to simulate I/R injury using hypoxia/reoxygenation (H/R) assay. In vivo, we used C57BL/6 mice to construct I/R injury model. The infarct area was examined by TTC staining. The level of miR-26a-5p and PTEN was determined by bioinformatics methods, qRT-PCR, and western blot. In addition, the viability and apoptosis of cardiomyocytes were separately detected by MTT and flow cytometry. The targeting relationship between miR-26a-5p and PTEN was analyzed by the TargetScan website and luciferase reporter assay. I/R and H/R treatment induced myocardial tissue injury and cardiomyocyte apoptosis, respectively. The results showed that miR-26a-5p was down-regulated in myocardial I/R injury. PTEN was found to be a direct target of miR-26a-5p. Furthermore, miR-26a-5p effectively improved viability and inhibited apoptosis in cardiomyocytes upon I/R injury by inhibiting PTEN expression to activate the PI3K/AKT signaling pathway. miR-26a-5p could protect cardiomyocytes against I/R injury by regulating the PTEN/PI3K/AKT pathway, which offers a potential approach for myocardial I/R injury treatment.

MiR-30e Attenuates Isoproterenol-induced Cardiac Fibrosis Through Suppressing Snai1/TGF-β Signaling

Background:

MicroRNAs are a class of small RNA molecules that inhibit protein expression through either degradation of messenger RNA or interference with protein translation. Our previous work suggested an involvement of miR-30e in myocardial fibrosis; however, the exact role of miR-30e in the pathogenesis of cardiac fibrosis and the underlying mechanisms are not known.

Methods:

Male Sprague Dawley rats were treated with isoproterenol (ISO) to induce cardiac remodeling and fibrosis and treated with either miR-30e agomir (AG) or antagomir and respective controls. The expression of miR-30e was evaluated by reverse transcription and quantitative polymerase chain reaction. Myocardial fibrosis was assessed by Masson's trichrome staining, and the level of oxidative stress and the expression of Snai1 and transforming growth factor-beta (TGF-β) were detected using Western blots.

Results:

A significant downregulation of miR-30e was found in the hearts of ISO-treated rats with cardiac fibrosis compared with nontreated controls. In vivo administration of miR-30e AG increased the survival of ISO-treated rats compared with AG-negative control administration, which was associated with reduced oxidative stress. We further identified Snai1 as a novel miR-30e target. Snai1 expression was significantly increased in hearts from ISO-treated rats, which coincided with decreased miR-30e expression and increased TGF-β expression. An miR-30e putative target sequence was identified in the 3′-untranslated region (UTR) Snai1. In a reporter assay, miR-30e greatly suppressed the activity of wild-type 3′-UTR–fused luciferase reporter, but showed no significant effect with the mutated 3′-UTR–fused reporter.

Conclusion:

MiR-30e attenuated ISO-induced cardiac dysfunction and cardiac fibrosis in a rat cardiac remodeling model. Mechanistically, miR-30e suppressed Snai1/TGF-β pathway which was involved in ISO-induced cardiac remodeling.

In silico identification of microRNAs predicted to regulate N-myristoyltransferase and Methionine Aminopeptidase 2 functions in cancer and infectious diseases

Protein myristoylation is a key protein modification carried out by N-Myristoyltransferase (NMT) after Methionine aminopeptidase 2 (MetAP2) removes methionine from the amino-terminus of the target protein. Protein myristoylation by NMT augments several signaling pathways involved in a myriad of cellular processes, including developmental pathways and pathways that when dysregulated lead to cancer or immune dysfunction. The emerging evidence pointing to NMT-mediated myristoylation as a major cellular regulator underscores the importance of understanding the framework of this type of signaling event. Various studies have investigated the role that myristoylation plays in signaling dysfunction by examining differential gene or protein expression between normal and diseased states, such as cancers or following HIV-1 infection, however no study exists that addresses the role of microRNAs (miRNAs) in the regulation of myristoylation. By performing a large scale bioinformatics and functional analysis of the miRNAs that target key genes involved in myristoylation (NMT1, NMT2, MetAP2), we have narrowed down a list of promising candidates for further analysis. Our condensed panel of miRNAs identifies 35 miRNAs linked to cancer, 21 miRNAs linked to developmental and immune signaling pathways, and 14 miRNAs linked to infectious disease (primarily HIV). The miRNAs panel that was analyzed revealed several NMT-targeting mRNAs (messenger RNA) that are implicated in diseases associated with NMT signaling alteration, providing a link between the realms of miRNA and myristoylation signaling. These findings verify miRNA as an additional facet of myristoylation signaling that must be considered to gain a full perspective. This study provides the groundwork for future studies concerning NMT-transcript-binding miRNAs, and will potentially lead to the development of new diagnostic/prognostic biomarkers and therapeutic targets for several important diseases.

miR-195 inhibits the proliferation and migration of chondrocytes by targeting GIT1

Previous studies have demonstrated that G-protein coupled receptor kinase interacting protein-1 (GIT1) and microRNAs (miRNAs) serve an important role in chondrocyte proliferation and migration. However, a limited number of studies conducted thus far have investigated the association between GIT1 and miRNAs. In the present study, putative miR‑195 binding sites in the GIT1 3'‑untranslated region were identified using common bioinformatic algorithms (miRanda, TargetScan, miRBase and miRWalk), and it was demonstrated that they may be involved in regulating GIT1 expression. Following transfection of miR‑195 mimics in chondrocytes, the expression of GIT1 was significantly reduced, whereas the expression was significantly increased following transfection with miR‑195 inhibitors. In addition, the results of the current study demonstrated that increased miR‑195 expression may downregulate chondrocyte proliferation and reduce cell migration. However, chondrocyte proliferation and migration was enhanced following suppression of miR‑195 expression. Furthermore, upon co‑transfection of miR‑195 and GIT1 expression vectors, the inhibitory effect of miR‑195 on chondrocyte proliferation and migration was attenuated. Therefore, miR‑195 may affect chondrocyte proliferation and migration via targeted regulation of GIT1 expression. The results of the current study provide novel evidence for the regulatory mechanisms of miRNAs in bone and cartilage tissues, which may facilitate further research and provide a greater understanding of different osteoarticular diseases.

miR-410 controls adult SVZ neurogenesis by targeting neurogenic genes

Over-expression of the early neural inducer, Noggin, in nestin positive subventricular zone (SVZ), neural stem cells (NSC) promotes proliferation and neuronal differentiation of neural progenitors and inhibits the expression of a CNS-enriched microRNA-410 (miR-410) (Morell et al., 2015). When expressed in neurospheres derived from the adult SVZ, miR-410 inhibits neuronal and oligodendrocyte differentiation, and promotes astrocyte differentiation. miR-410 also reverses the increase in neuronal differentiation and decreased astroglial differentiation caused by Noggin over-expression. Conversely, inhibition of miR-410 activity promotes neuronal and decreases astroglial differentiation of NSC. Using computer prediction algorithms and luciferase reporter assays we identified multiple neurogenic genes including Elavl4 as downstream targets of miR-410 via the canonical miRNA-3'UTR interaction. Over-expression of Elavl4 transcripts without the endogenous 3'UTR rescued the decrease in neuronal differentiation caused by miR-410 overexpression. Interestingly, we also observed that miR-410 affected neurite morphology; over-expression of miR-410 resulted in the formation of short, unbranched neurites. We conclude that miR-410 expression provides a new link between BMP signaling and the crucial lineage choice of adult neural stem cells via its ability to bind and control the expression of neurogenic gene transcripts.

Notch-regulated miR-223 targets the aryl hydrocarbon receptor pathway and increases cytokine production in macrophages from rheumatoid arthritis patients

Evidence links aryl hydrocarbon receptor (AHR) activation to rheumatoid arthritis (RA) pathogenesis, although results are inconsistent. AHR agonists inhibit pro-inflammatory cytokine expression in macrophages, pivotal cells in RA aetiopathogenesis, which hints at specific circuits that regulate the AHR pathway in RA macrophages. We compared microRNA (miR) expression in CD14⁺ cells from patients with active RA or with osteoarthritis (OA). Seven miR were downregulated and one (miR-223) upregulated in RA compared to OA cells. miR-223 upregulation correlated with reduced Notch3 and Notch effector expression in RA patients. Overexpression of the Notch-induced repressor HEY-1 and co-culture of healthy donor monocytes with Notch ligand-expressing cells showed direct Notch-mediated downregulation of miR-223. Bioinformatics predicted the AHR regulator ARNT (AHR nuclear translocator) as a miR-223 target. Pre-miR-223 overexpression silenced ARNT 3’UTR-driven reporter expression, reduced ARNT (but not AHR) protein levels and prevented AHR/ARNT-mediated inhibition of pro-inflammatory cytokine expression. miR-223 counteracted AHR/ARNT-induced Notch3 upregulation in monocytes. Levels of ARNT and of CYP1B1, an AHR/ARNT signalling effector, were reduced in RA compared to OA synovial tissue, which correlated with miR-223 levels. Our results associate Notch signalling to miR-223 downregulation in RA macrophages, and identify miR-223 as a negative regulator of the AHR/ARNT pathway through ARNT targeting.

Mesenchymal stem cells for the management of inflammation in osteoarthritis: state of the art and perspectives

Osteoarthritis (OA) is the most common form of degenerative arthritis, mainly characterized by the degradation of articular cartilage and associated with subchondral bone lesions. Novel therapeutic approaches for OA include cell-based therapies that have become thriving areas of research and development. In this context, mesenchymal stem or stromal cells (MSCs) have gained much interest based on their trophic and immunomodulatory properties that can help tissue repair/regeneration. The present review article discusses the interest of using MSCs in cell-therapy approaches with a focus on the mechanisms by which MSCs might exhibit a therapeutic potential in OA. Special attention is given to the anti-inflammatory function of MSCs and on miRNA modulation in OA for possible future innovative strategies. The paper also presents the current data on the undergoing MSCs-based clinical trials in OA.

Profiling peripheral microRNAs in obesity and type 2 diabetes mellitus

Mechanisms of type 2 diabetes mellitus (T2DM) remain elusive, in which obesity (OB) is considered as one of the major risk factors for the disease. A microRNA (miRNA) is a small non-coding RNA molecule functioning in RNA silencing and post-transcriptional regulation of gene expression. It has been demonstrated that some miRNAs can exist in serum stably and is closely related to various diseases. The goal of our study was to identify whether the deregulation of serum miRNAs was associated with T2DM and obesity. Twenty-five subjects with T2DM2, 25 healthy controls, 25 subjects with obesity, and 25 subjects with T2DM combined with obesity were included in the study. A total of 536 miRNA serum samples from these four groups were studied by miRNA polymerase chain reaction (PCR) panels. Data showed that miR-152 and miR-17 were significantly elevated in the OB group, whereas miR-138 was significantly decreased in OB group when compared to controls, T2DM, or T2DM+obesity group. In addition, level of MiR-593 was significantly lower in T2DM group and T2DM+obesity group when compared with controls. Further analysis revealed that the four miRNAs can be used as potential biomarkers to distinguish obesity from T2DM, OB+T2DM, and healthy subjects. Our study is one of the pioneer studies showing the differences in peripheral miRNA level in obesity, T2DM and T2DM combined with obesity. The study results suggest the potential utility of miRNAs in the prediction for obesity and T2DM.

New and emerging treatments for osteoarthritis management: will the dream come true with personalized medicine?

INTRODUCTION

Osteoarthritis (OA) is a dynamic process involving the main tissues of the joint for which a global approach should be considered. No disease-modifying OA drug (DMOAD) has yet been approved. New therapeutic strategies are needed that would be cost effective by reducing the need for pharmacological interventions and surgical management while targeting specific pathways leading to OA. The treatment landscape of OA is about to change based on new agents having shown some structural effects and emerging therapies with DMOAD effects.

AREAS COVERED

In this review based on a Medline (via PubMed) search, promising new and emerging therapies with a potential structural effect (DMOAD) will be discussed including growth factors, platelet-rich plasma, autologous stem cells, bone remodeling modulators, cytokine inhibition, gene therapy, and RNA interference.

EXPERT OPINION

DMOAD development should focus on targeting some phenotypes of OA patients evidenced with sensitive techniques such as magnetic resonance imaging, as a single treatment will unlikely be appropriate for all OA patients. This will allow the development of DMOADs based on personalized medicine. An exciting new era in DMOAD development is within reach, provided future clinical trials are sufficiently powered, systematically designed, use the appropriate evaluation tools, and target the appropriate categories of OA patients.

Plasma miR-126 is a potential biomarker for early prediction of type 2 diabetes mellitus in susceptible individuals

Type 2 diabetes mellitus (T2DM) is a major public health problem in China. Diagnostic markers are urgently needed to identify individuals at risk of developing T2DM and encourage them to adapt to a healthier life style. Circulating miRNAs present important sources of noninvasive biomarkers of various diseases. Recently, a novel plasma microRNA signature was identified in T2DM. Here, we evaluated the T2DM-related miRNA signature in plasma of three study groups: normal (fasting glucose (FG), 4.8–5.2 mmol/L), T2DM-susceptible (FG, 6.1–6.9 mmol/L), and T2DM individuals (FG, ≥7.0 mmol/L) and tested the feasibility of using circulating miRNAs to identify individuals at risk of developing T2DM. Among the 5 miRNAs included in the signature, miR-29b and miR-28-3p are not detectable. miR-15a and miR-223 have comparable expression levels among three groups. Notably, miR-126 is the only miRNA that showed significantly reduced expression in susceptible individuals and T2DM patients compared to normal individuals, suggesting that miR-126 in circulation may serve as a potential biomarker for early identification of susceptible individuals to T2DM.

MicroRNAs in sensorineural diseases of the ear

Non-coding microRNAs (miRNAs) have a fundamental role in gene regulation and expression in almost every multicellular organism. Only discovered in the last decade, miRNAs are already known to play a leading role in many aspects of disease. In the vertebrate inner ear, miRNAs are essential for controlling development and survival of hair cells. Moreover, dysregulation of miRNAs has been implicated in sensorineural hearing impairment, as well as in other ear diseases such as cholesteatomas, vestibular schwannomas, and otitis media. Due to the inaccessibility of the ear in humans, animal models have provided the optimal tools to study miRNA expression and function, in particular mice and zebrafish. A major focus of current research has been to discover the targets of the miRNAs expressed in the inner ear, in order to determine the regulatory pathways of the auditory and vestibular systems. The potential for miRNAs manipulation in development of therapeutic tools for hearing impairment is as yet unexplored, paving the way for future work in the field.