MicroRNA therapy stimulates uncontrolled cardiac repair after myocardial infarction in pigs.

Prompt coronary catheterization and revascularization have markedly improved the outcomes of myocardial infarction, but have also resulted in a growing number of surviving patients with permanent structural damage of the heart, which frequently leads to heart failure. There is an unmet clinical need for treatments for this condition1, particularly given the inability of cardiomyocytes to replicate and thereby regenerate the lost contractile tissue2. Here we show that expression of human microRNA-199a in infarcted pig hearts can stimulate cardiac repair. One month after myocardial infarction and delivery of this microRNA through an adeno-associated viral vector, treated animals showed marked improvements in both global and regional contractility, increased muscle mass and reduced scar size. These functional and morphological findings correlated with cardiomyocyte de-differentiation and proliferation. However, subsequent persistent and uncontrolled expression of the microRNA resulted in sudden arrhythmic death of most of the treated pigs. Such events were concurrent with myocardial infiltration of proliferating cells displaying a poorly differentiated myoblastic phenotype. These results show that achieving cardiac repair through the stimulation of endogenous cardiomyocyte proliferation is attainable in large mammals, however dosage of this therapy needs to be tightly controlled.

Phase 1 study of MRX34, a liposomal miR-34a mimic, in patients with advanced solid tumours.

BACKGROUND: In this first-in-human, Phase 1 study of a microRNA-based cancer therapy, the recommended Phase 2 dose (RP2D) of MRX34, a liposomal mimic of microRNA-34a (miR-34a), was determined and evaluated in patients with advanced solid tumours. METHODS: Adults with various solid tumours refractory to standard treatments were enrolled in 3 + 3 dose-escalation cohorts and, following RP2D determination, expansion cohorts. MRX34, with oral dexamethasone premedication, was given intravenously daily for 5 days in 3-week cycles. RESULTS: Common all-cause adverse events observed in 85 patients enrolled included fever (% all grade/G3: 72/4), chills (53/14), fatigue (51/9), back/neck pain (36/5), nausea (36/1) and dyspnoea (25/4). The RP2D was 70 mg/m2 for hepatocellular carcinoma (HCC) and 93 mg/m2 for non-HCC cancers. Pharmacodynamic results showed delivery of miR-34a to tumours, and dose-dependent modulation of target gene expression in white blood cells. Three patients had PRs and 16 had SD lasting ≥4 cycles (median, 19 weeks, range, 11-55). CONCLUSION: MRX34 treatment with dexamethasone premedication demonstrated a manageable toxicity profile in most patients and some clinical activity. Although the trial was closed early due to serious immune-mediated AEs that resulted in four patient deaths, dose-dependent modulation of relevant target genes provides proof-of-concept for miRNA-based cancer therapy. CLINICAL TRIAL REGISTRATION: NCT01829971.

Phase I study of MRX34, a liposomal miR-34a mimic, administered twice weekly in patients with advanced solid tumors.

Purpose Naturally occurring tumor suppressor microRNA-34a (miR-34a) downregulates the expression of >30 oncogenes across multiple oncogenic pathways, as well as genes involved in tumor immune evasion, but is lost or under-expressed in many malignancies. This first-in-human, phase I study assessed the maximum tolerated dose (MTD), safety, pharmacokinetics, and clinical activity of MRX34, a liposomal miR-34a mimic, in patients with advanced solid tumors. Patients and Methods Adult patients with solid tumors refractory to standard treatment were enrolled in a standard 3 + 3 dose escalation trial. MRX34 was given intravenously twice weekly (BIW) for three weeks in 4-week cycles. Results Forty-seven patients with various solid tumors, including hepatocellular carcinoma (HCC; n = 14), were enrolled. Median age was 60 years, median prior therapies was 4 (range, 1-12), and most were Caucasian (68%) and male (57%). Most common adverse events (AEs) included fever (all grade %/G3%: 64/2), fatigue (57/13), back pain (57/11), nausea (49/2), diarrhea (40/11), anorexia (36/4), and vomiting (34/4). Laboratory abnormalities included lymphopenia (G3%/G4%: 23/9), neutropenia (13/11), thrombocytopenia (17/0), increased AST (19/4), hyperglycemia (13/2), and hyponatremia (19/2). Dexamethasone premedication was required to manage infusion-related AEs. The MTD for non-HCC patients was 110 mg/m2, with two patients experiencing dose-limiting toxicities of G3 hypoxia and enteritis at 124 mg/m2. The half-life was >24 h, and Cmax and AUC increased with increasing dose. One patient with HCC achieved a prolonged confirmed PR lasting 48 weeks, and four patients experienced SD lasting ≥4 cycles. Conclusion MRX34 treatment with dexamethasone premedication was associated with acceptable safety and showed evidence of antitumor activity in a subset of patients with refractory advanced solid tumors. The MTD for the BIW schedule was 110 mg/m2 for non-HCC and 93 mg/m2 for HCC patients. Additional dose schedules of MRX34 have been explored to improve tolerability.

Nanomedicine Meets microRNA: Current Advances in RNA-Based Nanotherapies for Atherosclerosis.

Cardiovascular disease (CVD) accounts for almost half of all deaths worldwide and has now surpassed infectious disease as the leading cause of death and disability in developing countries. At present, therapies such as low-density lipoprotein-lowering statins and antihypertensive drugs have begun to bend the morality curve for coronary artery disease (CAD); yet, as we come to appreciate the more complex pathophysiological processes in the vessel wall, there is an opportunity to fine-tune therapies to more directly target mechanisms that drive CAD. MicroRNAs (miRNAs) have been identified that control vascular cell homeostasis,(1-3) lipoprotein metabolism,(4-9) and inflammatory cell function.(10) Despite the importance of these miRNAs in driving atherosclerosis and vascular dysfunction, therapeutic modulation of miRNAs in a cell- and context-specific manner has been a challenge. In this review, we summarize the emergence of miRNA-based therapies as an approach to treat CAD by specifically targeting the pathways leading to the disease. We focus on the latest development of nanoparticles (NPs) as a means to specifically target the vessel wall and what the future of these nanomedicines may hold for the treatment of CAD.

Adipocyte-derived exosomal miRNAs: a novel mechanism for obesity-related disease.

BACKGROUND: Obesity is frequently complicated by comorbid conditions, yet how excess adipose contributes is poorly understood. Although adipocytes in obese individuals induce systemic inflammation via secreted cytokines, another potential mediator has recently been identified (i.e., adipocyte-derived exosomes). We hypothesized that adipocyte-derived exosomes contain mediators capable of activating end-organ inflammatory and fibrotic signaling pathways. METHODS: We developed techniques to quantify and characterize exosomes shed by adipocytes from seven obese (age: 12-17.5 y, BMI: 33-50 kg/m(2)) and five lean (age: 11-19 y, BMI: 22-25 kg/m(2)) subjects. RESULTS: Abundant exosomal miRNAs, but no mRNAs, were detected. Comparison of obese vs. lean visceral adipose donors detected 55 differentially expressed miRNAs (P < 0.05; fold change ≥|1.2|). qRT-PCR confirmed downregulation of miR-148b (ratio = 0.2 (95% confidence interval = 0.1, 0.6)) and miR-4269 (0.3 (0.1, 0.8)), and upregulation of miR-23b (6.2 (2.2, 17.8)) and miR-4429 (3.8 (1.1-13.4)). Pathways analysis identified TGF-ß signaling and Wnt/ß-catenin signaling among the top canonical pathways expected to be altered with visceral adiposity based on projected mRNA targets for the 55 differentially expressed miRNAs. A select mRNA target was validated in vitro. CONCLUSION: These data show that visceral adipocytes shed exosomal-mediators predicted to regulate key end-organ inflammatory and fibrotic signaling pathways.

MicroRNA-15a and microRNA-16 impair human circulating proangiogenic cell functions and are increased in the proangiogenic cells and serum of patients with critical limb ischemia.

RATIONALE: Circulating proangiogenic cells (PACs) support postischemic neovascularization. Cardiovascular disease and diabetes mellitus impair PAC regenerative capacities via molecular mechanisms that are not fully known. We hypothesize a role for microRNAs (miRs). Circulating miRs are currently investigated as potential diagnostic and prognostic biomarkers. OBJECTIVE: The objectives were the following: (1) to profile miR expression in PACs from critical limb ischemia (CLI) patients; (2) to demonstrate that miR-15a and miR-16 regulate PAC functions; and (3) to characterize circulating miR-15a and miR-16 and to investigate their potential biomarker value. METHODS AND RESULTS: Twenty-eight miRs potentially able to modulate angiogenesis were measured in PACs from CLI patients with and without diabetes mellitus and controls. miR-15a and miR-16 were further analyzed. CLI-PACs expressed higher level of mature miR-15a and miR-16 and of the primary transcript pri-miR-15a/16-1. miR-15a/16 overexpression impaired healthy PAC survival and migration. Conversely, miR-15a/16 inhibition improved CLI-PAC-defective migration. Vascular endothelial growth factor-A and AKT-3 were validated as direct targets of the 2 miRs, and their protein levels were reduced in miR-15a/16-overexpressing healthy PACs and in CLI-PACs. Transplantation of healthy PACs ex vivo-engineered with anti-miR-15a/16 improved postischemic blood flow recovery and muscular arteriole density in immunodeficient mice. miR-15a and miR-16 were present in human blood, including conjugated to argonaute-2 and in exosomes. Both miRs were increased in the serum of CLI patients and positively correlated with amputation after restenosis at 12 months postrevascularization of CLI type 2 diabetes mellitus patients. Serum miR-15a additionally correlated with restenosis at follow-up. CONCLUSIONS: Ex vivo miR-15a/16 inhibition enhances PAC therapeutic potential, and circulating miR-15a and miR-16 deserves further investigation as a prognostic biomarker in CLI patients undergoing revascularization.

Cardiovascular RNA interference therapy: the broadening tool and target spectrum.

Understanding of the roles of noncoding RNAs (ncRNAs) within complex organisms has fundamentally changed. It is increasingly possible to use ncRNAs as diagnostic and therapeutic tools in medicine. Regarding disease pathogenesis, it has become evident that confinement to the analysis of protein-coding regions of the human genome is insufficient because ncRNA variants have been associated with important human diseases. Thus, inclusion of noncoding genomic elements in pathogenetic studies and their consideration as therapeutic targets is warranted. We consider aspects of the evolutionary and discovery history of ncRNAs, as far as they are relevant for the identification and selection of ncRNAs with likely therapeutic potential. Novel therapeutic strategies are based on ncRNAs, and we discuss here RNA interference as a highly versatile tool for gene silencing. RNA interference-mediating RNAs are small, but only parts of a far larger spectrum encompassing ncRNAs up to many kilobasepairs in size. We discuss therapeutic options in cardiovascular medicine offered by ncRNAs and key issues to be solved before clinical translation. Convergence of multiple technical advances is highlighted as a prerequisite for the translational progress achieved in recent years. Regarding safety, we review properties of RNA therapeutics, which may immunologically distinguish them from their endogenous counterparts, all of which underwent sophisticated evolutionary adaptation to specific biological contexts. Although our understanding of the noncoding human genome is only fragmentary to date, it is already feasible to develop RNA interference against a rapidly broadening spectrum of therapeutic targets and to translate this to the clinical setting under certain restrictions.

RNAimmuno: a database of the nonspecific immunological effects of RNA interference and microRNA reagents.

The RNAimmuno database was created to provide easy access to information regarding the nonspecific effects generated in cells by RNA interference triggers and microRNA regulators. Various RNAi and microRNA reagents, which differ in length and structure, often cause non-sequence-specific immune responses, in addition to triggering the intended sequence-specific effects. The activation of the cellular sensors of foreign RNA or DNA may lead to the induction of type I interferon and proinflammatory cytokine release. Subsequent changes in the cellular transcriptome and proteome may result in adverse effects, including cell death during therapeutic treatments or the misinterpretation of experimental results in research applications. The manually curated RNAimmuno database gathers the majority of the published data regarding the immunological side effects that are caused in investigated cell lines, tissues, and model organisms by different reagents. The database is accessible at http://rnaimmuno.ibch.poznan.pl and may be helpful in the further application and development of RNAi- and microRNA-based technologies.

Silencing mutant ATXN3 expression resolves molecular phenotypes in SCA3 transgenic mice.

Spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disease caused by a polyglutamine expansion in the deubiquitinating enzyme, Ataxin-3. Currently, there are no effective treatments for this fatal disorder but studies support the hypothesis that reducing mutant Ataxin-3 protein levels might reverse or halt the progression of disease in SCA3. Here, we sought to modulate ATXN3 expression in vivo using RNA interference. We developed artificial microRNA mimics targeting the 3'-untranslated region (3'UTR) of human ATXN3 and then used recombinant adeno-associated virus to deliver them to the cerebellum of transgenic mice expressing the full human disease gene (SCA3/MJD84.2 mice). Anti-ATXN3 microRNA mimics effectively suppressed human ATXN3 expression in SCA3/MJD84.2 mice. Short-term treatment cleared the abnormal nuclear accumulation of mutant Ataxin-3 throughout the transduced SCA3/MJD84.2 cerebellum. Analysis also revealed changes in the steady-state levels of specific microRNAs in the cerebellum of SCA3/MJD84.2 mice, a previously uncharacterized molecular phenotype of SCA3 that appears to be dependent on mutant Ataxin-3 expression. Our findings support the preclinical development of molecular therapies aimed at halting the expression of ATXN3 as a viable approach to SCA3 and point to microRNA deregulation as a potential surrogate marker of SCA3 pathogenesis.

[Analysis on the association of single nucleotide polymorphism in the promoter region of pre-miR-320b-2 with coronary heart disease risk and factors influencing circulating microRNA-320b level].

OBJECTIVE: To investigate the effects of rs10916581, a common single nucleotide polymorphism (SNP) located in the promoter region of pre-miR-320b-2, on coronary heart disease (CHD) risk and circulating microRNA-320b (miR-320b) level. To explore potential factors influencing circulating miR-320b level. METHODS: Rs10916581 was genotyped in a case-control study with 1 507 CHD cases and 1 379 age- and sex-frequency-matched controls. The cases were consecutively recruited from 3 hospitals (Tongji Hospital, Union Hospital, and Wugang Hospital) in Wuhan city (Hubei, China) between May 2004 and October 2009 and all the controls resided in Wuhan communities. A subgroup of 174 CHD cases and 181 non-diabetes controls without acute infection were randomly selected and their circulating miR-320b levels were detected using quantitative reverse transcriptase polymerase chain reaction assays. The association of rs10916581 with CHD susceptibility was analyzed with multivariable logistic regression model. Generalized linear regression model was used to explore the associations of rs10916581 and some other factors with circulating miR-320b level. RESULTS: In single-factor logistic regression analysis, no association was found between rs10916581 and CHD risk. After adjustment for age, sex, BMI, smoking status, hypertension, diabetes, total triglyceride, total cholesterol/high density lipoprotein (TC/HDL-C), the result did not materially alter(compared with CC genotype, the OR (95%CI) of CHR in the subjects carried CT, TT, CT+TT genotypes were 0.94 (0.76-1.15), 0.99 (0.74-1.33) and 0.95 (0.78-1.16) ). No significant interactions were observed between the conventional risk factors of CHD (age, gender, smoking status, BMI, hypertension, diabetes, CHD family history) and rs10916581 on CHD risk (P > 0.05). Rs10916581 showed no significant association with circulating miR-320b level in cases, controls or total population (ß(95%CI) was -0.028 (-0.495-0.440), 0.250 (-0.226-0.727) and 0.134 (-0.218-0.486) respectively, P > 0.05). However, circulating miR-320b level was negatively associated with BMI (ß (95%CI) was -0.140 (-0.261--0.020), P = 0.022) while positively associated with TC/HDL(ß (95%CI) was 0.620 (0.261-0.979), P = 0.001) in cases, and in total population, its circulating level tended to be lower in diabetes or hypertension patients (ß(95%CI) was -1.025 (-1.696--0.354) and -0.594 (-1.138--0.049) respectively, P = 0.003, 0.033 respectively) and was positively associated with TC/HDL-C (ß(95%CI) was 0.108 (0.027-0.190), P = 0.009). CONCLUSION: The common SNP (rs10916581) in the promoter region of pre-miR-320b-2 might have little contribution to the CHD predisposition in Chinese Han population, and it might not affect circulating miR-320b level. Conventional CHD risk factors (BMI, TC/HDL-C, hypertension and diabetes) might have effects on its circulating level.

Using microRNA as an alternative treatment for hyperlipidemia and cardiovascular disease: cardio-miRs in the pipeline.

It is now appreciated that over 90% of the human genome is comprised of noncoding RNAs that have the ability to affect other components of the genome and regulate gene expression. This has galvanized the development of RNA-based therapeutics for a myriad of diseases, including cancer, inflammatory conditions, and cardiovascular disease. Several classes of RNA therapeutics are currently under clinical development, including antisense oligonucleotides, small interfering RNA, and microRNA mimetics and inhibitors. The field of antisense technology saw a huge leap forward with the recent Food and Drug Administration approval of the first antisense therapy, directed against apolipoprotein B, for the treatment of familial hypercholesterolemia. In addition, recent progress in the development of approaches to inhibit microRNAs has helped to illuminate their roles in repressing gene networks and also revealed their potential as therapeutic targets. In this review, these exciting opportunities in the field of drug discovery, with a focus on emerging therapeutics in the field of cardiovascular disease, are summarized.

The Risks of miRNA Therapeutics: In a Drug Target Perspective.

RNAi therapeutics have been growing. Patisiran and givosiran, two siRNA-based drugs, were approved by the Food and Drug Administration in 2018 and 2019, respectively. However, there is rare news on the advance of miRNA drugs (another therapeutic similar to siRNA drug). Here we report the existing obstacles of miRNA therapeutics by analyses for resources available in a drug target perspective, despite being appreciated when it began. Only 10 obtainable miRNA drugs have been in clinical trials with none undergoing phase III, while over 60 siRNA drugs are in complete clinical trial progression including two approvals. We mechanically compared the two types of drug and found that their major distinction lay in the huge discrepancy of the target number of two RNA molecules, which was caused by different complementary ratios. One miRNA generally targets tens and even hundreds of genes. We named it "too many targets for miRNA effect" (TMTME). Further, two adverse events from the discontinuation of two miRNA therapeutics were exactly answered by TMTME. In summary, TMTME is inevitable because of the special complementary approach between miRNA and its target. It means that miRNA therapeutics would trigger a series of unknown and unpreventable consequences, which makes it a considerable alternative for application.

A comprehensive study to delineate the role of an extracellular vesicle-associated microRNA-29a in chronic methamphetamine use disorder.

Extracellular vesicles (EVs), which express a repertoire of cargo molecules (cf. proteins, microRNA, lipids, etc.), have been garnering a prominent role in the modulation of several cellular processes. Here, using both non-human primate and rodent model systems, we provide evidence that brain-derived EV (BDE) miRNA, miR-29a-3p (mir-29a), is significantly increased during chronic methamphetamine (MA) exposure. Further, miR-29a levels show significant increase both with drug-seeking and reinstatement in a rat MA self-administration model. We also show that EV-associated miR-29a is enriched in EV pool comprising of small EVs and exomeres and further plays a critical role in MA-induced inflammation and synaptodendritic damage. Furthermore, treatment with the anti-inflammatory drug ibudilast (AV411), which is known to reduce MA relapse, decreased the expression of miR-29a and subsequently attenuated inflammation and rescued synaptodendritic injury. Finally, using plasma from MUD subjects, we provide translational evidence that EV-miR29a could potentially serve as a biomarker to detect neuronal damage in humans diagnosed with MA use disorder (MUD). In summary, our work suggests that EV-associated miR-29a-3p plays a crucial role in MUD and might be used as a potential blood-based biomarker for detecting chronic inflammation and synaptic damage.

Circulating miR-27b as a Biomarker of the Development and Progression of Carotid Artery Stenosis.

OBJECTIVE: A close relationship of microRNAs (miRNAs) with various human diseases has been widely reported, including cardiovascular disease. The current study attempted to examine the abnormal expression of miR-27b in asymptomatic carotid artery stenosis (ACAS), its diagnostic value and predictive value for the development of ACAS were also assessed. METHODS: Clinical serum samples were collected from both ACAS patients and healthy individuals, and levels of miR-27b in the clinical samples were detected using Real-time quantitative PCR. Cerebral ischemia events (CIEs) of patients during the 5-year follow-up were collected. The diagnostic and predictive values of serum miR-27b was assessed via plotting Receiver operating characteristic (ROC) and Kaplan-Meier curves. Multivariate cox regression analysis was performed for clinical independent index analysis. RESULTS: ACAS patients had higher levels of miR-27b than the healthy subjects. There were close association of serum miR-27b levels with total cholesterol (TC) level, absence of hypertension and degree of carotid stenosis. High levels of miR-27b could differentiate ACAS cases from healthy subjects, and predicted the high incidence of CIEs. MiR-27b could be used as an independent predictor of cerebrovascular events via multiple Cox regression analysis (P = .031). CONCLUSION: The high level of miR-27b can predict the occurrence of ACAS, and is closely related to the subsequent occurrence of CIEs. The present results provide evidence for circulating miR-27b as a diagnostic and prognostic marker in patients with ACAS.

Therapeutic effects of micro-RNAs in preclinical studies of acute kidney injury: a systematic review and meta-analysis.

AKI has a high mortality rate, may lead to chronic kidney disease, and effective therapies are lacking. Micro-RNAs (miRNAs) regulate biologic processes by potently inhibiting protein expression, and pre-clinical studies have explored their roles in AKI. We conducted a systematic review and meta-analysis of miRNAs as therapeutics in pre-clinical AKI. Study screening, data extraction, and quality assessments were performed by 2 independent reviewers. Seventy studies involving 42 miRNA species were included in the analysis. All studies demonstrated significant effects of the miRNA intervention on kidney function and/or histology, with most implicating apoptosis and phosphatase and tensin homolog (PTEN) signaling. Fourteen studies (20.0%) examined the effect of miRNA-21 in AKI, and meta-analysis demonstrated significant increases in serum creatinine and kidney injury scores with miR-21 antagonism and pre-conditioning. No studies reported on adverse effects of miRNA therapy. Limitations also included lack of model diversity (100% rodents, 61.4% ischemia-reperfusion injury), and predominance of male sex (78.6%). Most studies had an unclear risk of bias, and the majority of miRNA-21 studies were conducted by a single team of investigators. In summary, several miRNAs target kidney function and apoptosis in pre-clinical AKI models, with data suggesting that miRNA-21 may mediate protection and kidney repair.Systematic review registration ID: CRD42019128854.

CircPAG1 Inhibits the High Glucose-Induced Lens Epithelial Cell Injury by Sponging miR-630 and Upregulating EPHA2.

Background: Circular RNAs (circRNAs) have been considered as vital regulators in the progression of human ocular diseases, including diabetic cataract (DC). This report was designed to research the biological role of circRNA phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (circPAG1) in high glucose (HG)-induced lens epithelial damages.Methods: Lens epithelial damage in DC was investigated by the effects of 25 mM glucose (HG) on human lens epithelial cells (HLE-B3). CircPAG1, microRNA-630 (miR-630), and ephrin type-A receptor 2 (EPHA2) levels were examined by the quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation analysis was performed by 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay and colony formation assay. Cell apoptosis was measured through flow cytometry. Protein levels were detected using western blot. Oxidative stress was determined by malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) levels via the corresponding kits. Dual-luciferase reporter and RNA immunoprecipitation (RIP) and RNA pull-down assays were used for target binding analysis.Results: CircPAG1 expression was downregulated in lens samples of DC patients and HG-treated lens epithelial cells. HG inhibited cell growth but promoted apoptosis and oxidative stress in HLE-B3 cells, while circPAG1 overexpression relieved these damages. Moreover, circPAG1 was identified as a molecular sponge for miR-630. HG-induced cell injury was also attenuated by the inhibition of miR-630, and the function of circPAG1 was related to its sponge effect on miR-630. In addition, miR-630 directly targeted EPHA2 and circPAG1 could regulate the EPHA2 expression via sponging miR-630. Furthermore, we found that the protective role of circPAG1 against the HG-induced cell injury was ascribed to the upregulation of EPHA2.Conclusion: Our evidence suggested that circPAG1 alleviated cell damages in HG-treated human lens epithelial cells by regulating the miR-630/EPHA2 axis.

miR-384-5p regulates inflammation in Candida albicans-induced acute lung injury by downregulating PGC1ß and enhancing the activation of Candida albicans-triggered signaling pathways.

Acute lung injury (ALI) is one of the most prevalent respiratory syndromes of excessive inflammatory reaction during lung infection. Candida albicans (C. albicans) infection is among the leading causes of ALI. MicroRNAs (miRNAs) regulate the expression of target mRNAs, including those involved in inflammatory processes, by binding to the 3'UTR. To date, the roles of miRNAs in C. albicans-induced ALI remain unclear. In this study, we investigated the role of miR-384-5p in C. albicans-induced ALI and its underlying molecular mechanism. RT-PCR, Western blot, ELISA, Myeloperoxidase (MPO) assay, microRNA target analysis, transient transfection, and luciferase reporter assay were utilized. In vivo study was conducted on mouse model. The expression of miR-384-5p was upregulated and positively correlated with inflammatory cytokine production in lung tissues and RAW264.7 and J774A.1 macrophages infected with C. albicans. The miR-384-5p inhibitor alleviated the inflammatory reaction induced by C. albicans. Target prediction analysis revealed that PGC1ß was a target of miR-384-5p, which was further validated by the PGC1ß 3'-UTR luciferase assay and the inverse correlation between the expression of miR-384-5p and PGC1ß in C. albicans-infected ALI tissues and macrophages. Moreover, macrophages transfected with miR-384-5p mimic exhibited reduced levels of PGC1ß. The suppression of the expression of PGC1ß by C. albicans infection in the macrophages was abrogated by miR-384-5p inhibitor. Then, we demonstrated that PGC1ß played an inhibitory role in C. albicans-induced production of inflammatory cytokines. Furthermore, suppression of miR-384-5p in macrophages inhibited the activation of the NF-κB, MAPK, and Akt signaling pathways triggered by C. albicans, but not the STAT3 pathway. These results demonstrate that miR-384-5p contributes to C. albicans-induced ALI at least in part by targeting PGC1ß and enhancing the activation of the NF-κB, MAPK, and Akt inflammatory signaling pathways. Thus, targeting miR-384-5p might exert a protective effect on C. albicans-induced ALI.

Non-coding RNA therapeutics for cardiac regeneration.

A growing body of evidence indicates that cardiac regeneration after myocardial infarction can be achieved by stimulating the endogenous capacity of cardiomyocytes (CMs) to replicate. This process is controlled, both positively and negatively, by a large set of non-coding RNAs (ncRNAs). Some of the microRNAs (miRNAs) that can stimulate CM proliferation is expressed in embryonic stem cells and is required to maintain pluripotency (e.g. the miR-302∼367 cluster). Others also govern the proliferation of different cell types, including cancer cells (e.g. the miR-17∼92 cluster). Additional miRNAs were discovered through systematic screenings (e.g. miR-199a-3p and miR-590-3p). Several miRNAs instead suppress CM proliferation and are involved in the withdrawal of CMs from the cell cycle after birth (e.g. the let-7 and miR-15 families). Similar regulatory roles on CM proliferation are also exerted by a few long ncRNAs. This body of information has obvious therapeutic implications, as miRNAs with activator function or short antisense oligonucleotides against inhibitory miRNAs or lncRNAs can be administered to stimulate cardiac regeneration. Expression of miRNAs can be achieved by gene therapy using adeno-associated vectors, which transduce CMs with high efficiency. More effective and safer for therapeutic purposes, small nucleic acid therapeutics can be obtained as chemically modified, synthetic molecules, which can be administered through lipofection or inclusion in lipid or polymer nanoparticles for efficient cardiac delivery. The notion that it is possible to reprogramme CMs into a regenerative state and that this property can be enhanced by ncRNA therapeutics remains exciting, however extensive experimentation in large mammals and rigorous assessment of safety are required to advance towards clinical application.

Artificial microRNAs as siRNA shuttles: improved safety as compared to shRNAs in vitro and in vivo.

RNA interference (RNAi) provides a promising therapeutic approach to human diseases. However, data from recent reports demonstrate that short-hairpin RNAs (shRNAs) may cause cellular toxicity, and this warrants further investigation of the safety of using RNAi vectors. Earlier, in comparing hairpin-based RNAi vectors, we noted that shRNAs are highly expressed and yield an abundance of unprocessed precursors, whereas artificial microRNAs (miRNAs) are expressed at lower levels and are processed efficiently. We hypothesized that unprocessed shRNAs arise from the saturation of endogenous RNAi machinery, which poses likely a burden to cells. In this study, we tested that hypothesis by assessing the relative effects of shRNAs and artificial miRNAs on the processing and function of miRNAs. In competition assays, shRNAs disrupted miRNA biogenesis and function, whereas artificial miRNAs avoided this interference even when dosed to silence as effectively as shRNAs. We next compared the safety of these vectors in mouse cerebella, and found that shRNAs cause Purkinje cell neurotoxicity. By contrast, artificial miRNA expression was well tolerated, resulting in effective target gene silencing in Purkinje cells. These findings, together with data from earlier work in mouse striata, suggest that miRNA-based platforms are better suited for therapeutic silencing in the mammalian brain.

Not miR-ly small RNAs: big potential for microRNAs in therapy.

RNA interference (RNAi) describes a set of natural processes in which genes are silenced by small RNAs. RNAi has been widely used as an experimental tool that has recently become the focus of drug development efforts to treat a variety of diseases and disorders. Like all molecular therapies, in vivo delivery is the major hurdle to realizing therapeutic RNAi. Several strategies have been developed that increase small RNA half-life in the blood, facilitate transduction across biological membranes, and mediate cell-specific delivery. Importantly, these strategies permit targeting of mRNAs as well as microRNAs (miRNAs), a class of small RNAs encoded in the genome. miRNAs are required for multiple developmental and cellular processes. Dysfunction of miRNAs can result in a host of pathologies, suggesting that miRNAs are potential targets of therapy. Recent studies of miRNA function in immune-specific pathways indicate that specific miRNAs might be exploited as therapeutic targets to treat immune disorders, including autoimmunity, allergy, and hematopoietic cancers.