Rapid changes in microRNA-146a expression negatively regulate the IL-1beta-induced inflammatory response in human lung alveolar epithelial cells

Roles of microRNAs in T cell immunity: Implications for strategy development against infectious diseases

T cell immunity plays a vital role in pathogen infections. MicroRNA (miRNAs) are small, single-stranded noncoding RNAs that regulate T cell immunity by targeting key transcriptional factors, signaling proteins, and cytokines associated with T cell activation, differentiation, and function. The dysregulation of miRNA expression in T cells may lead to specific immune responses and can provide new therapeutic opportunities against various infectious diseases. Here, we summarize recent studies that focus on the roles of miRNAs in T cell immunity and highlight miRNA functions in prevalent infectious diseases. Additionally, we also provide insights into the functions of extracellular vesicle miRNAs and attempt to delineate the mechanism of miRNA sorting into extracellular vesicles and their immunomodulatory functions. Moreover, methodologies and strategies for miRNA delivery against infectious diseases are summarized. Finally, potential strategies for miRNA-based therapies are proposed.

The association between the miR-146a rs2910164 C>G polymorphism and Kawasaki disease in a southern Chinese population

miR-146a plays a critical role in innate immune and inflammatory responses. Kawasaki disease involves immune-mediated inflammatory responses, which leads to vascular endothelial injury. However, there has been no study on the association between the miR-146a rs2910164 C>G polymorphism and Kawasaki disease risk. We enrolled 532 Kawasaki disease patients and 623 healthy controls from southern Chinese population, and the miR-146a rs2910164 C>G polymorphism was genotyped by the TaqMan method. There was no evidence that this polymorphism was associated with Kawasaki disease. Stratified analysis also showed no significant association. The present study indicates that the miR-146a rs2910164 C>G polymorphism may not be associated with Kawasaki disease in the southern Chinese population. Larger multicenter studies are needed to confirm our conclusions.

Association of the miR-196a2, miR-146a, and miR-499 Polymorphisms with Asthma Phenotypes in a Korean Population

BACKGROUND

MicroRNAs (miRNAs) modulate expressions of inflammatory genes, thereby regulating inflammatory responses. Single nucleotide polymorphisms (SNPs) in miRNAs could affect their efficiency in binding to messenger RNAs (mRNAs).

OBJECTIVE

We investigated the associations of miRNA SNPs with asthma phenotypes. miR-196a2 (rs11614913 T>C), miR-146a (rs2910164 C>G), and miR-499 (rs3746444 A>G) were genotyped in 347 asthma patients and 172 normal healthy controls (NCs).

RESULTS

The CT/CC genotype of miR-196a2 rs11614913 was associated with eosinophilic asthma (p = 0.004) and a higher sputum eosinophil count compared with the TT genotype (p = 0.003). The CG/GG genotype of miR-146a rs2910164 tended to be associated with higher bronchial hyperresponsiveness to methacholine (PC₂₀) compared with the CC genotype. The AG/GG genotype of miR-499 rs3746444 was associated with higher predicted values of forced expiratory volume in 1 s (%FEV₁) compared with the AA genotype (p = 0.008).

CONCLUSIONS

Genetic polymorphisms in miR-196a2, miR-146a, and miR-499 could be potential biomarkers for asthma phenotypes and targets for asthma treatments in a Korean population.

CRISPR/Cas9-mediated deletion of miR-146a enhances antiviral response in HIV-1 infected cells

The human immunodeficiency virus type 1 (HIV-1) causes persistent infection in human and induces miR-146a expression in infected cells. miR-146a represses the innate immune response by inhibiting the expression of TRAF6 and IRAK1 genes, thus negatively controls the NF-κB-related cytokines and interferon stimulated genes. Here we reported that lentiviral CRISPR/Cas9 system was highly efficient in introducing mutations in the precursor miR-146a genomic sequences, resulting in a loss of miR-146a expression and function. miR-146a ablation led to increasing cytokines production in LPS-stimulated A549 cells. Moreover, miR-146a knockout in HIV-1 infected MT2 cells markedly increased the expression of cytokines and HIV-1 restriction factors and reversed T cell exhaustion markers expression, thus influencing HIV-1 replication. Our study indicates that lentiviral CRISPR/Cas9-mediated gene editing is an effective approach to abrogate miR-146a expression, which consequently inhibits HIV-1 replication as well as proviral reactivation by enhancing the expression of cytokines and HIV-1 restriction factors.

HIV-1-Induced miR-146a Attenuates Monocyte Migration by Targeting CCL5 in Human Primary Macrophages

MicroRNAs (miRNAs) are widely involved in immune regulation during virus infection. Several studies showed that the expression of miR-146a was increased in human immunodeficiency virus type I (HIV-1)-infected cells, but the definitive function of miR-146a in HIV-1 infection remains obscure. The production of chemokine (C-C motif) ligand 5 (CCL5) in macrophages has been reported to play an important role in HIV/AIDS-associated pathogenesis. In this study, we examined the effects of miR-146a on CCL5 regulation in HIV-1-infected macrophages. Gain and loss of function studies showed that CCL5 might be one of the miR-146a targets, as miR-146a mimic reduced, while miR-146a inhibitor increased CCL5 production in HIV-1-infected macrophages. In addition, we demonstrated that miR-146a reduced CCL5-induced monocyte migration. Our study provided evidence that miR-146a targets CCL5 3' untranslated regions, downregulates its release from macrophages, and affects monocyte migration consequently. These findings drew a novel layer of posttranscriptional control of the chemokine CCL5 by miR-146a during HIV infection, which might contribute to HIV pathogenesis.

MiR-146a regulates PM1 -induced inflammation via NF-κB signaling pathway in BEAS-2B cells

Exposure to particulate matter (PM) leads to kinds of cardiopulmonary diseases, such as asthma, COPD, arrhythmias, lung cancer, etc., which are related to PM-induced inflammation. We have found that PM_2.5 (aerodynamics diameter <2.5 µm) exposure induces inflammatory response both in vivo and in vitro. Since the toxicity of PM is tightly associated with its size and components, PM₁ (aerodynamics diameter <1.0 µm) is supposed to be more toxic than PM_2.5 . However, the mechanism of PM₁ -induced inflammation is not clear. Recently, emerging evidences prove that microRNAs play a vital role in regulating inflammation. Therefore, we studied the regulation of miR-146a in PM₁ -induced inflammation in human lung bronchial epithelial BEAS-2B cells. The results show that PM₁ induces the increase of IL-6 and IL-8 in BEAS-2B cells and up-regulates the miR-146a expression by activating NF-κB signaling pathway. Overexpressed miR-146a prevents the nuclear translocation of p65 through inhibiting the IRAK1/TRAF6 expression, and downregulates the expression of IL-6 and IL-8. Taken together, these results demonstrate that miR-146a can negatively feedback regulate PM₁ -induced inflammation via NF-κB signaling pathway in BEAS-2B cells.

Expression analysis of extracellular microRNA in bronchoalveolar lavage fluid from patients with pulmonary sarcoidosis

BACKGROUND AND OBJECTIVE

MicroRNA (miRNA) are transcriptional regulators implicated in pulmonary sarcoidosis and packaged in extracellular vesicles (EV) during cellular communication. We characterized EV and investigated miRNA expression in bronchoalveolar lavage (BAL) fluid from sarcoidosis patients.

METHODS

EV were characterized for size(s) using dynamic light scattering and transmission electron microscopy (TEM) analysis and protein markers by immunoblotting. Twelve extracellular and 5 cellular miRNA were investigated in BAL from 16 chest X-ray stage-I (CXR-I) and 17 CXR stage-II (CXR-II) sarcoidosis patients. Associations between miRNA and disease characteristics (extrapulmonary involvement, pulmonary function and BAL cell profile) were statistically analysed.

RESULTS

BAL from sarcoidosis patients contained exosomes and microvesicles (MV) as EV. In these EV, expression of miR-146a (P = 0.007), miR-150 (P = 0.003) and BAL cellular miR-21 (P = 0.01) was increased in CXR-II compared with CXR-I. Other detected EV (miR-21 and miR-26a) and cellular (miR-31, miR-129-3p, miR-146a and miR-452) miRNA were not differentially expressed. The investigated miRNA did not reflect extrapulmonary involvement, but EV miR-146a and miR-150 were negatively correlated with pulmonary function (miR-146a with vital capacity (VC; Spearman's correlation coefficient (r_s ), P = -0.657, 0.007), percent predicted forced expiratory volume in 1 s (FEV₁ ; -0.662, 0.006) and FEV₁ /forced vital capacity (FVC) ratio (-0.649, 0.008); miR-150 correlated negatively with VC (-0.584, 0.019) and FEV₁ /FVC ratio (-0.746, 0.001) in CXR-II cases).

CONCLUSION

Our data provide evidence that exosomes and microvesicles as extracellular vesicles are present in the bronchoalveolar space of sarcoidosis patients and they differentially express EV miRNA (miR-146a and miR-150), the expression of which correlates negatively with pulmonary function indices. The significance of these findings for disease pathophysiology and clinical course require further investigation.

Anti-Inflammatory MicroRNAs and Their Potential for Inflammatory Diseases Treatment

Inflammation is a complicated biological and pathophysiological cascade of responses to infections and injuries, and inflammatory mechanisms are closely related to many diseases. The magnitude, the complicated network of pro- and anti-inflammatory factors, and the direction of the inflammatory response can impact on the development and progression of various disorders. The currently available treatment strategies often target the symptoms and not the causes of inflammatory disease and may often be ineffective. Since the onset and termination of inflammation are crucial to prevent tissue damage, a range of mechanisms has evolved in nature to regulate the process including negative and positive feedback loops. In this regard, microRNAs (miRNAs) have emerged as key gene regulators to control inflammation, and it is speculated that they are fine-tune signaling regulators to allow for proper resolution and prevent uncontrolled progress of inflammatory reactions. In this review, we discuss recent findings related to significant roles of miRNAs in immune regulation, especially the potential utility of these molecules as novel anti-inflammatory agents to treat inflammatory diseases. Furthermore, we discuss the possibilities of using miRNAs as drugs in the form of miRNA mimics or miRNA antagonists.

MicroRNA-223 inhibits deposition of the extracellular matrix by airway smooth muscle cells through targeting IGF-1R in the PI3K/Akt pathway

Asthma is a wide-spread disease that significantly impacts health throughout the world. A key aspect of the pathology of the disease is the remodeling of the airways by airway smooth muscle cells (ASMCs). MicroRNAs play an important role in post-transcriptional gene regulation and are involved in numerous biological functions, including those linked to asthma. A large number of microRNAs have been identified and investigated in various cell types to assess their function. In the present study, the role and potential mechanisms of miR-223 in ASMCs were investigated. Overexpression of miR-223 was found to induce a phenotypic switch in ASMCs that led to decreased expression of proteins involved in the extracellular matrix, such as α-SMA (ACTA2), and type I and III collagens. Inhibition of miR-223 caused the opposite result. However, unlike mast cells, neither overexpression nor inhibition of miR-223 affected cell viability or apoptosis in ASMCs. To further understand the effects of miR-223 on ASMCs, we applied bioinformatics analysis using predictive software, in combination with western blotting, to reveal that insulin-like growth factor-1 receptor (IGF-1R) was the functional target of miR-223 that leads to the phenotypic switch of ASMCs. Suppression of luciferase activity in a reporter containing the 3'-untranslated region (3'-UTR) of IGF-1R confirmed that this region is the target for the miRNA. Finally, we showed that miR-223 suppressed IGF-1R expression and decreased downstream phosphorylation of Akt (AKT1) in ASMCs. In conclusion, our data demonstrate that miR-223 exerts an inhibitory effect on the fibrotic phenotypes of ASMCs via the PI3K/Akt signaling pathway and IGF-1R is the likely functional target of the microRNA.

miR-146a C/G polymorphism increased the risk of head and neck cancer, but overall cancer risk: an analysis of 89 studies

Several studies have evaluated the association of miR-146a C/G with head and neck cancer (HNC) susceptibility, and overall cancer risk, but with inconclusive outcomes. To drive a more precise estimation, we carried out this meta-analysis. The literature was searched from MEDLINE (mainly PubMed), Embase, the Cochrane Library, and Google Scholar databases to identify eligible studies. A total of 89 studies were included. The results showed that miR-146a C/G was significantly associated with increased HNC risk in dominant model (I² =15.6%, P_{heterogeneity}=0.282, odds ratio (OR) =1.088, 95% confidence interval (CI) =1.002–1.182, P=0.044). However, no cancer risk was detected under all genetic models. By further stratified analysis, we found that rs4919510 mutation contributed to the risk of HNC amongst Asians under homozygote model (I² =0, P_{heterogeneity}=0.541, OR =1.189, 95% CI =1.025–1.378, P=0.022), and dominant model (I² =0, P_{heterogeneity}=0.959, OR =1.155, 95% CI =1.016–1.312, P=0.028). Simultaneously, in the stratified analysis by source of controls, a significantly increased cancer risk amongst population-based studies was found under homozygote model, dominant model, recessive model, and allele comparison model. However, no significant association was found in the stratified analysis by ethnicity and source of control. The results indicated that miR-146a C/G polymorphism may contribute to the increased HNC susceptibility and could be a promising target to forecast cancer risk for clinical practice. However, no significant association was found in subgroup analysis by ethnicity and source of control. To further confirm these results, well-designed large-scale case–control studies are needed in the future.

Extracellular vesicles regulate immune responses and cellular function in intestinal inflammation and repair

Tightly controlled communication among the various resident and recruited cells in the intestinal tissue is critical for maintaining tissue homeostasis, re-establishment of the barrier function and healing responses following injury. Emerging evidence convincingly implicates extracellular vesicles (EVs) in facilitating this important cell-to-cell crosstalk by transporting bioactive effectors and genetic information in healthy tissue and disease. While many aspects of EV biology, including release mechanisms, cargo packaging, and uptake by target cells are still not completely understood, EVs contribution to cellular signaling and function is apparent. Moreover, EV research has already sparked a clinical interest, as a potential diagnostic, prognostic and therapeutic tool. The current review will discuss the function of EVs originating from innate immune cells, namely, neutrophils, monocytes and macrophages, as well as intestinal epithelial cells in healthy tissue and inflammatory disorders of the intestinal tract. Our discussion will specifically emphasize the contribution of EVs to the regulation of vascular and epithelial barrier function in inflamed intestines, wound healing, as well as trafficking and activity of resident and recruited immune cells.

Noncoding RNAs in Cardiovascular Disease: Pathological Relevance and Emerging Role as Biomarkers and Therapeutics

Noncoding RNAs (ncRNA) include a diverse range of functional RNA species-microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) being most studied in pathophysiology. Cardiovascular morbidity is associated with differential expression of myriad miRNAs; miR-21, miR-155, miR-126, miR-146a/b, miR-143/145, miR-223, and miR-221 are the top 9 most reported miRNAs in hypertension and atherosclerotic disease. A single miRNA may have hundreds of messenger RNA targets, which makes a full appreciation of the physiologic ramifications of such broad-ranging effects a challenge. miR-21 is the most prominent ncRNA associated with hypertension and atherosclerotic disease due to its role as a "mechano-miR", responding to arterial shear stresses. "Immuno-miRs", such as miR-155 and miR-223, affect cardiovascular disease (CVD) via regulation of hematopoietic cell differentiation, chemotaxis, and activation in response to many pro-atherogenic stimuli. "Myo-miRs", such as miR-1 and miR-133, affect cardiac muscle plasticity and remodeling in response to mechanical overload. This in-depth review analyzes observational and experimental reports of ncRNAs in CVD, including future applications of ncRNA-based strategies in diagnosis, prediction (e.g., survival and response to small molecule therapy), and biologic therapy.

Spirulina diet to lactating mothers protects the antioxidant system and reduces inflammation in post-natal brain after systemic inflammation

OBJECTIVES

This study concerns: (1) the long-term effects of peripheral lipopolysaccharide (LPS) in neonatal rats on inflammation and antioxidant parameters in brain and (2) the effects of a Spirulina-enriched diet given to lactating mothers on protective and inflammatory parameters in brains of suckling pups subjected to peripheral inflammation.

METHODS

Five-day old rat pups were treated with LPS (i.p. 2 mg/kg). After 3, 7, 30, and 65 days, mRNA, miRNA, and protein levels of pro-inflammatory cytokines and the Nuclear factor E2-related factor 2 (Nrf2)-system were examined. In a sub-group, a Spirulina-enriched diet was given to the mothers 24 hours before the pups were treated with LPS, then the effects on antioxidant and inflammatory parameters were evaluated.

RESULTS

The main findings were: (1) interleukin 1 beta (IL-1β) was upregulated in cortex 3, 7, and 30 days after LPS treatment, (2) Nrf2 and the catalytic subunit of γ-glutamylcysteinyl ligase were decreased in cortex 7 days after LPS in parallel with increased levels of phosphorylated p38 and decreased levels of histone H3 acetylation, and (3) a Spirulina-enriched diet to lactating mothers normalized both the increased IL-1β expression and the decreased antioxidant parameters after LPS. The protective effects of Spirulina were correlated with decreased levels of phosphorylated p38 and high levels of the antioxidant miRNA-146a.

DISCUSSION

A Spirulina diet given to lactating mothers can protect against neuroinflammation and decreased antioxidant defence in brain of suckling pups subjected to peripheral inflammation, possibly via decreased activation of p38 and high levels of the antioxidant miRNA-146a.

Hypoxia-induced microRNA-146a represses Bcl-2 through Traf6/IRAK1 but not Smad4 to promote chondrocyte autophagy

It has been shown that hypoxia stimulation promotes chondrocytes autophagy partly through HIF-1α, miR-146a and Bcl-2 progressively, and this mechanism represented the connection among hypoxia, miR-146a and autophagy, and provides a possible therapeutic strategy for osteoarthritis. However, the interaction between miR-146a and Bcl-2 is still unclear. Here in a hypoxic environment, we quantified the three reported miR-146a targets: two inflammation related targets Traf6, IRAK1; and the only reported target in chondrocytes Smad4. We confirmed the regulative function of miR-146a between hypoxia and these genes, and explored the Bcl-2 expression and autophagy level under extrinsic up-regulation of these three gene separately. All the three genes were down-regulated by hypoxia. Surprisingly, Traf6 and IRAK, but not the unique Smad4 in chondrocytes, were restored by antagomiR-146a. Both Ad-Traf6 and Ad-IRAK1 reinstated hypoxia or miR-146a repressed Bcl-2. However, Ad-Smad4 did not affect Bcl-2 in hypoxia or normoxia. The autophagy level showed a reverse variability compared to Bcl-2. Taken together, our results provided evidence that Smad4, the unique reported target for miR-146a in chondrocytes is unusually not involved in the chondrocytes autophagy, while the Traf6 and IRAK1 are the new targets for miR-146a in chondrocytes during autophagy.

Functional diversity of miR-146a-5p and TRAF6 in normal and oral cancer cells

Numerous studies implicate miR-146a as pleiotropic regulator of carcinogenesis; however, its roles in carcinogenesis are not fully understood. A clue from expression analyses of miR-146a-5p in all 13 oral squamous cell carcinoma (OSCC) cell lines examined and in OSCC tissues, whole blood and whole saliva of OSCC patients in vivo revealed that miR‑146a-5p expression was highly upregulated. Particularly, we widened the view of its upregulation in saliva, implicating that high miR-146a-5p expression is not only correlated closely to the development of human oral cancer, but also to a possible candidate as a diagnostic marker of OSCC. Indeed, further examination showed that exogenous miR-146a-5p expression showed pleiotropic effects on cell proliferation and apoptosis which were partially based on the contextual responses of activation of JNK, downstream of TRAF6 that was targeted by miR-146a-5p in normal human keratinocytes and OSCC cell lines. TRAF6 suppression by a TRAF6-specific siRNA resulted in contradictory consequences on cellular processes in normal and OSCC cells. Notably, TRAF6 downregulation by both miR-146a-5p and TRAF6-specific siRNA deactivated JNK in SCC-9, but not in normal human keratinocytes. In support of the proliferation-promoting effect of miR-146a-5p, silencing of endogenous miR-146a-5p significantly reduced proliferation of SCC-9. Together, these results suggest that miR-146a-5p affects proliferation and apoptosis in a cellular context-dependent manner and selectively disarms the TRAF6-mediated branch of the TGF-β signaling in OSCC cell lines by sparing Smad4 involvement.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

The use of electronic cigarettes (e-cigs) is increasing rapidly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plausible that e-cig use might affect similar inflammatory pathways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers (e.g., adolescents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the potential for inducing inflammation, albeit much less than smoking. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary biomarkers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers. Cancer Epidemiol Biomarkers Prev; 26(8); 1175-91. ©2017 AACR.

MicroRNAs in mucosal inflammation

Of the total human body's surface, the majority is internal surface, belonging to the lungs (100 m²) and intestinal tract (400 m²). In comparison, the external surface area, belonging to the skin, comprises less than 1% (2 m²). Continuous exposure of the mucosal surface to external factors (e.g., pathogens, food particles) requires tight regulation to maintain homeostasis. MicroRNAs (miRNAs) have gained noticeable attention as playing important roles in maintaining the steady-state of tissues by modulating immune functions and inflammatory responses. Accordingly, associations have been found between miRNA expression levels and human health conditions and diseases. These findings have important implications in inflammatory diseases involving pulmonary and intestinal mucosa, such as acute lung injury or inflammatory bowel disease. In this review, we highlight the known biology of miRNAs and discuss the role of miRNAs in modulating mucosal defense and homeostasis. Additionally, we discuss miRNAs serving as potential therapeutic targets to treat immunological conditions, particularly mucosal inflammation.

Identification of differentially expressed miRNAs associated with chronic kidney disease-mineral bone disorder

The purpose of this study is to characterize a meta-signature of differentially expressed mRNA in chronic kidney disease (CKD) to predict putative microRNA (miRNA) in CKD-mineral bone disorder (CKD-MBD) and confirm the changes in these genes and miRNA expression under uremic conditions by using a cell culture system. PubMed searches using MeSH terms and keywords related to CKD, uremia, and mRNA arrays were conducted. Through a computational analysis, a meta-signature that characterizes the significant intersection of differentially expressed mRNA and expected miRNAs associated with CKD-MBD was determined. Additionally, changes in gene and miRNA expressions under uremic conditions were confirmed with human Saos-2 osteoblast-like cells. A statistically significant mRNA meta-signature of upregulated and downregulated mRNA levels was identified. Furthermore, miRNA expression profiles were inferred, and computational analyses were performed with the imputed microRNA regulation based on weighted ranked expression and putative microRNA targets (IMRE) method to identify miRNAs associated with CKD occurrence. TLR4 and miR-146b levels were significantly associated with CKD-MBD. TLR4 levels were significantly downregulated, whereas primiR- 146b and miR-146b were upregulated in the presence of uremic toxins in human Saos-2 osteoblast-like cells. Differentially expressed miRNAs associated with CKD-MBD were identified through a computational analysis, and changes in gene and miRNA expressions were confirmed with an in vitro cell culture system.

miR-146a-5p plays an essential role in the aberrant epithelial-fibroblast cross-talk in COPD

We previously reported that epithelial-derived interleukin (IL)-1α drives fibroblast-derived inflammation in the lung epithelial-mesenchymal trophic unit. Since miR-146a-5p has been shown to negatively regulate IL-1 signalling, we investigated the role of miR-146a-5p in the regulation of IL-1α-driven inflammation in chronic obstructive pulmonary disease (COPD).Human bronchial epithelial (16HBE14o-) cells were co-cultured with control and COPD-derived primary human lung fibroblasts (PHLFs), and miR-146a-5p expression was assessed with and without IL-1α neutralising antibody. Genomic DNA was assessed for the presence of the single nucleotide polymorphism (SNP) rs2910164. miR-146a-5p mimics were used for overexpression studies to assess IL-1α-induced signalling and IL-8 production by PHLFs.Co-culture of PHLFs with airway epithelial cells significantly increased the expression of miR-146a-5p and this induction was dependent on epithelial-derived IL-1α. miR-146a-5p overexpression decreased IL-1α-induced IL-8 secretion in PHLFs via downregulation of IL-1 receptor-associated kinase-1. In COPD PHLFs, the induction of miR-146a-5p was significantly less compared with controls and was associated with the SNP rs2910164 (GG allele) in the miR-146a-5p gene.Our results suggest that induction of miR-146a-5p is involved in epithelial-fibroblast communication in the lungs and negatively regulates epithelial-derived IL-1α induction of IL-8 by fibroblasts. The decreased levels of miR-146a-5p in COPD fibroblasts may induce a more pro-inflammatory phenotype, contributing to chronic inflammation in COPD.

MiR-146b is down-regulated during the chondrogenic differentiation of human bone marrow derived skeletal stem cells and up-regulated in osteoarthritis

Articular cartilage injury can result in chondrocyte loss and diminishment of specialised extracellular matrix, which can progress to an osteoarthritic (OA) phenotype. Stem cells have emerged as a favourable approach for articular cartilage regeneration. Identification of miRNAs which influence stem cell fate offers new approaches for application of miRNAs to regenerate articular cartilage. Skeletal stem cells (SSCs) isolated from human bone marrow were cultured as high density micromass' using TGF-β3 to induce chondrogenesis. qPCR and TaqMan qPCR were used to assess chondrogenic gene and miRNA expression. Target prediction algorithms identified potential targets of miR-146b. Transient transfection with miR-146b mimic and western blotting was used to analyse SOX5. Human OA articular chondrocytes were examined for miR-146b expression. Chondrogenic differentiation of human bone marrow derived SSCs resulted in significant down-regulation of miR-146b. Gain of miR-146b function resulted in down-regulation of SOX5. MiR-146b expression was up-regulated in OA chondrocytes. These findings demonstrate the functional role of miR-146b in the chondrogenic differentiation of human bone marrow derived SSCs. MiR-146b may play a role in the pathophysiology of OA. Application of miR-146b combined with stem cell therapy could enhance regeneration of cartilaginous tissue and serve as a potential therapeutic target in the treatment of OA.

MicroRNA-146a contributes to CD4+ T lymphocyte differentiation in patients with thyroid ophthalmopathy

MicroRNA-146a (miR-146a) is associated with human inflammatory disease, such as thyroid-associated ophthalmopathy (TAO), but its role in human T cells and relevance to TAO remains ambiguous. In this study, T cells of TAO patients showed downregulated expression of miR-146a. We characterized miR-146a in T cells and examined miR-146a as a critical inhibitor of Th1 differentiation processes. MiR-146a inhibited Th1 differentiation processes and cell proliferation of T-lymphocytes. Thus, the results showed that miR-146a was a potent inhibitor of Th1 differentiation and cell proliferation of human T cells and dysregulation of miR-146a contributed to the pathogenesis of TAO.

MiR-146a/b: a family with shared seeds and different roots

MicroRNAs are small, noncoding, RNAs known for their powerful modulation of molecular processes, making them a major focus for studying pathological mechanisms. The human miR-146 family of microRNAs consists of two member genes, MIR146A and MIR146B These two microRNAs are located on different chromosomes and exhibit differential regulation in many cases. However, they are nearly identical in sequence, sharing a seed region, and are thus predicted to target the same set of genes. A large proportion of the microRNA (miR)-146 literature focuses on its role in regulating the innate immune response in the context of various pathologies by modulating two widely studied target genes in the toll-like receptor signaling cascade. A growing subset of the literature reports a role of miR-146 in cardiovascular and renal disease, and data suggest there is exciting potential for miR-146 as a diagnostic and therapeutic target. Nevertheless, the published literature is confounded by unclear and imprecise language concerning the specific effects of the two miR-146 family members. The present review will compare the genomic origin and regulation of miR-146a and miR-146b, discuss some approaches to overcome analytical and experimental challenges, and summarize findings in major areas of miR-146 research. Moving forward, careful evaluation of miR-146a/b specificity in analytical and experimental approaches will aid researchers in elucidating the functional relevance of differential regulation of the miR-146 family members in health and disease.

An Eye on Age-Related Macular Degeneration: The Role of MicroRNAs in Disease Pathology

Age-related macular degeneration (AMD) is the primary cause of blindness in developed countries, and is the third leading cause worldwide. Emerging evidence suggests that beside environmental and genetic factors, epigenetic mechanisms, such as microRNA (miRNA) regulation of gene expression, are relevant to AMD providing an exciting new avenue for research and therapy. MiRNAs are short, non-coding RNAs thought to be imperative for coping with cellular stress. Numerous studies have analyzed miRNA dysregulation in AMD patients, although with varying outcomes. Four studies which profiled dysregulated circulating miRNAs in AMD yielded unique sets, and there is only minimal overlap in ocular miRNA profiling of AMD. Mouse models of AMD, including oxygen-induced retinopathy and laser-induced choroidal neovascularization, showed similarities to some extent with miRNA patterns in AMD. For example, miR-146a is an extensively researched miRNA thought to modulate inflammation, and was found to be upregulated in AMD mice and cellular systems, but also in human AMD retinae and vitreous humor. Similarly, mir-17, miR-125b and miR-155 were dysregulated in multiple AMD mouse models as well as in human AMD plasma or retinae. These miRNAs are thought to regulate angiogenesis, apoptosis, phagocytosis, and inflammation. A promising avenue of research is the modulation of such miRNAs, as the phenotype of AMD mice could be ameliorated with antagomirs or miRNA-mimic treatment. However, before meaningful strides can be made to develop miRNAs as a diagnostic or therapeutic tool, reproducible miRNA profiles need to be established for the various clinical outcomes of AMD.

MicroRNA-21 contributes to suppress cytokines production by targeting TLR28 in teleost fish

Toll-like receptors (TLRs) as important pattern recognition receptors, play critical roles in identifying pathogens and activating the immune response. However, when the dysregulation was occurred in this process, it could lead to excessive immune response, so it need many regulatory factors to control this process. Recently, microRNAs (miRNAs) have been shown to act as an important regulator in TLRs signaling pathway. As a member of TLRs family, TLR28 has been newly discovered in teleost fish, and play an important role in the immune response. In this study, we found that the expression of miR-21 was up-regulated after poly(I:C) stimulation, and miR-21 could inhibit the expression of cytokines. Then we predicted the target genes of miR-21, and found that TLR28 is a direct target of miR-21, which could be significantly down-regulated by both miR-21 mimics and pre-miR-21. These results suggested that miR-21 can inhibit the expression of cytokines by negative regulation of TLR28, thereby inhibiting the generation of excessive immunity and maintaining the balance of the body. This study is the first to demonstrate that miRNA can suppresses cytokines by regulating the TLR signaling pathway in teleost fish, and also can provides some new ideas for the research of the regulation of miRNA and immune system in mammals.

Oligonucleotide Therapy for Obstructive and Restrictive Respiratory Diseases

Inhaled oligonucleotide is an emerging therapeutic modality for various common respiratory diseases, including obstructive airway diseases like asthma and chronic obstructive pulmonary disease (COPD) and restrictive airway diseases like idiopathic pulmonary fibrosis (IPF). The advantage of direct accessibility for oligonucleotide molecules to the lung target sites, bypassing systemic administration, makes this therapeutic approach promising with minimized potential systemic side effects. Asthma, COPD, and IPF are common chronic respiratory diseases, characterized by persistent airway inflammation and dysregulated tissue repair and remodeling, although each individual disease has its unique etiology. Corticosteroids have been widely prescribed for the treatment of asthma, COPD, and IPF. However, the effectiveness of corticosteroids as an anti-inflammatory drug is limited by steroid resistance in severe asthma, the majority of COPD cases, and pulmonary fibrosis. There is an urgent medical need to develop target-specific drugs for the treatment of these respiratory conditions. Oligonucleotide therapies, including antisense oligonucleotide (ASO), small interfering RNA (siRNA), and microRNA (miRNA) are now being evaluated both pre-clinically and clinically as potential therapeutics. The mechanisms of action of ASO and siRNA are highly target mRNA specific, ultimately leading to target protein knockdown. miRNA has both biomarker and therapeutic values, and its knockdown by a miRNA antagonist (antagomir) has a broader but potentially more non-specific biological outcome. This review will compile the current findings of oligonucleotide therapeutic targets, verified in various respiratory disease models and in clinical trials, and evaluate different chemical modification approaches to improve the stability and potency of oligonucleotides for the treatment of respiratory diseases.

MiR-146 and miR-125 in the regulation of innate immunity and inflammation

Innate immune responses are primary, relatively limited, and specific responses to numerous pathogens and toxic molecules. Protein expression involved in these innate responses must be tightly regulated at both transcriptional level and post-transcriptional level to avoid the development of excessive inflammation that can be potentially harmful to the host. MicroRNAs are small noncoding RNAs (∼22 nucleotides [nts]) that participate in the regulation of numerous physiological responses by targeting specific messenger RNAs to suppress their translation. Recent work has shown that several negative regulators of transcription including microRNAs play important roles in inhibiting the exacerbation of inflammatory responses and in the maintenance of immunological homeostasis. This emerging research area will provide new insights on how microRNAs regulate innate immune signaling. It might show that dysregulation of microRNA synthesis is associated with the pathogenesis of inflammatory and infectious diseases. In this review, we focused on miR-146 and miR-125 and described the roles these miRNAs in modulating innate immune signaling. These microRNAs can control inflammatory responses and the outcomes of pathogenic infections. [BMB Reports 2016; 49(6): 311-318]

miR-146a-mediated suppression of the inflammatory response in human adipocytes

The obesity-associated inflammation of white adipose tissue (WAT) is one of the factors leading to the development of related diseases such as insulin resistance and liver steatosis. Recently, microRNAs (miRNAs) were identified as important regulators of WAT functions. Herein, we cultured human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes with macrophage-conditioned medium (MacCM) and performed an Affimetrix miRNA array to identify miRNAs differentially expressed under inflammatory conditions. We identified 24 miRNAs differentially expressed upon inflammation in human adipocytes and miR-146a was the most up-regulated miRNA species. In subcutaneous WAT, miR-146a was elevated in both human and murine obesity. Transfection of miR-146a mimics prevented the MacCM-induced inflammatory response in SGBS adipocytes as seen by reduced levels of IL-8 and MCP-1 mRNA and protein. We identified IRAK1 and TRAF6 as targets of miR-146a in human adipocytes and detected a reduced inflammation-induced activation of JNK and p38 upon miR-146a transfection. Taken together, we could show that miR-146a reduces the inflammatory response in human adipocytes. In a negative feedback loop miR-146a might contribute to the regulation of inflammatory processes in WAT and possibly prevent an overwhelming inflammatory response.

Evaluation of the Tobacco Heating System 2.2 (THS2.2). Part 5: microRNA expression from a 90-day rat inhalation study indicates that exposure to THS2.2 aerosol causes reduced effects on lung tissue compared with cigarette smoke

Modified-risk tobacco products (MRTP) are designed to reduce the individual risk of tobacco-related disease as well as population harm compared to smoking cigarettes. Experimental proof of their benefit needs to be provided at multiple levels in research fields. Here, we examined microRNA (miRNA) levels in the lungs of rats exposed to a candidate modified-risk tobacco product, the Tobacco Heating System 2.2 (THS2.2) in a 90-day OECD TG-413 inhalation study. Our aim was to assess the miRNA response to THS2.2 aerosol compared with the response to combustible cigarettes (CC) smoke from the reference cigarette 3R4F. CC smoke exposure, but not THS2.2 aerosol exposure, caused global miRNA downregulation, which may be explained by the interference of CC smoke constituents with the miRNA processing machinery. Upregulation of specific miRNA species, such as miR-146a/b and miR-182, indicated that they are causal elements in the inflammatory response in CC-exposed lungs, but they were reduced after THS2.2 aerosol exposure. Transforming transcriptomic data into protein activity based on corresponding downstream gene expression, we identified potential mechanisms for miR-146a/b and miR-182 that were activated by CC smoke but not by THS2.2 aerosol and possibly involved in the regulation of those miRNAs. The inclusion of miRNA profiling in systems toxicology approaches increases the mechanistic understanding of the complex exposure responses.

Increased Levels of miRNA-146a in Serum and Histologic Samples of Patients with Uveal Melanoma

Purpose: To analyze MiRs expression in serum of UM patients, respect to healthy donors, and to compare this data with MiRs expressed in formalin-fixed, paraffin-embedded UM samples. Methods: Expression profile of 754 miRNAs was performed in serum of patients with uveal melanoma who underwent primary enucleation. The level of miRNAs increased in serum was individually analyzed on FFPE UM samples and compared to choroidal melanocytes from unaffected eyes. Results: Fourteen patients with uveal melanoma were included in the study. We found 8 serum miRNAs differentially expressed compared to normal controls: 2 upregulated miRNAs (miRNA-146a, miR-523); 6 downregulated miRNAs (miR-19a, miR-30d, miR-127, miR-451, miR-518f, miR-1274B). When data on upregulated miRNAs were singularly validated only a significant overexpression of miRNA-146a was found. A statistically significant upregulation of miRNA-146a was also found on FFPE UM samples, compared to choroidal melanocytes from unaffected eyes. Conclusions: miRNA-146a is increased in serum of patients with UM and in FFPE tumor samples. Further studies will show if it could be considered a potential marker of UM in the blood.

MicroR-146 blocks the activation of M1 macrophage by targeting signal transducer and activator of transcription 1 in hepatic schistosomiasis

Schistosomiasis is a chronic disease caused by the parasite of the Schistosoma genus and is characterized by egg-induced hepatic granulomas and fibrosis. Macrophages play a central role in schistosomiasis with several studies highlighting their differentiation into M2 cells involved in the survival of infected mice through limitation of immunopathology. However, little is known regarding the mechanisms of regulating macrophage differentiation. Here, we showed that the early stage of infection by Schistosoma japonicum induced expression of type 1 T-helper-cell (Th1) cytokine, interferon-γ (IFN-γ), leading to increase in M1 cells. However, the presence of liver-trapped eggs induced the expression of Th2 cytokines including interleukin-4 (IL-4), IL-10, and IL-13 that upregulated the transcription of miR-146b by activating signal transducer and activator of transcription 3/6 (STAT3/6) that bind to the promoter of the pre-miR-146b gene. We found that the miR-146a/b was significantly upregulated in macrophages during the progression of hepatic schistosomiasis. The elevated miR-146a/b inhibited the IFN-γ-induced differentiation of macrophages to M1 cells through targeting STAT1. Our data indicate the protective roles of miR-146a/b in hepatic schistosomiasis through regulating the differentiation of macrophages into M2 cells.

miR-146 was selectively upregulated in macrophages during hepatic schistosomiasis.

miR-146 blocked the differentiation of macrophages into M1 cells by targeting STAT1 in hepatic schistosomiasis.

Th2 cytokines induced the expression of miR-146b by activating STAT3/6 that bind to the promoter of the pre-miR-146b gene.

Th2 cytokines inhibited the activation of M1 macrophages by induction of miR-146b.

Macrophages play a central role in schistosomiasis by differentiating into various activation states. Previous studies have highlighted the importance of differentiation of macrophages into M2 cells for host survival. In this study, we revealed that the presence of liver-trapped parasite eggs induced expression of Th2 cytokines that promoted transcription of miR-146b by activating STAT3/6 that bind to the promoter of the pre-miR-146b gene, and the elevated miR-146b inhibited the IFN-γ-induced differentiation of macrophages into M1 cells by suppressing STAT1. These findings indicate the protective roles of miR-146a/b in hepatic schistosomiasis through regulating the differentiation of macrophages into M2 cells.

Clinical potential of oligonucleotide-based therapeutics in the respiratory system

The discovery of an ever-expanding plethora of coding and non-coding RNAs with nodal and causal roles in the regulation of lung physiology and disease is reinvigorating interest in the clinical utility of the oligonucleotide therapeutic class. This is strongly supported through recent advances in nucleic acids chemistry, synthetic oligonucleotide delivery and viral gene therapy that have succeeded in bringing to market at least three nucleic acid-based drugs. As a consequence, multiple new candidates such as RNA interference modulators, antisense, and splice switching compounds are now progressing through clinical evaluation. Here, manipulation of RNA for the treatment of lung disease is explored, with emphasis on robust pharmacological evidence aligned to the five pillars of drug development: exposure to the appropriate tissue, binding to the desired molecular target, evidence of the expected mode of action, activity in the relevant patient population and commercially viable value proposition.

Genome-wide analysis of aberrantly expressed microRNAs in bronchoalveolar lavage fluid from patients with silicosis

Background To identify differentially expressed miRNAs profiles in bronchoalveolar lavage fluid (BALF) from patients with silicosis and consider the potential contribution of miRNAs to silicosis.Methods miRNAs expression profiling were performed in the cell fraction of BALF samples obtained from 9 subjects (3 silicosis observation subjects, 3 stage I and stage II silicosis patients, respectively). The differential expression of two selected miRNAs hsa-miR-181c-5p and hsa-miR-29a-3p were confirmed by RT-qPCR. Furthermore, miRNAs Gene Ontology Enrichment categories and target mRNAs were determined based on miRWalk.Results We found 110 dysregulated miRNAs in silicosis samples, most of which showed a down-regulation trend. Microarray results were confirmed by RT-qPCR. With the observation group samples set as standards, stage I samples showed 123 differentially expressed miRNAs, and stage II 46. 23 miRNAs were dysregulated in both stages. Finally, functional enrichment analysis indicated that these miRNAs played an important role in various biological processes, including ECM-receptor interaction and endocytosis.Conclusions This is the first time to acquire the BALF-derived microRNAs expression profiling targeting to human silicosis. These results contribute to unravelling miRNAs involved in the pathogenesis of silicosis, and provide new tools of potential use of as biomarkers for diagnosis and/or therapeutic purposes.

Genomewide miRNA profiling of oral lichenoid disorders and oral squamous cell carcinoma

OBJECTIVE

To dissect the aberrant microRNA profile of oral lichenoid disorders (OLD) by analyzing the larger set of OLD samples tested so far.

MATERIALS AND METHODS

MicroRNA expression profiles were assessed using TLDA card in 32 samples (16 OLD, 8 OSCC, and 8 control). The findings were validated using RT-qPCR in an independent cohort of 91 samples.

RESULTS

We identified 20 differentially expressed microRNAs in OLD, of which several are functionally related to cell proliferation, response to organic substances, or immune processes. Further validation of the top-ranked microRNAs revealed that they were all aberrantly expressed in OLD.

CONCLUSION

We have identified a new microRNA signature associated with OLD that may provide a meaningful basis for better understanding the physiopathology of the disease. In addition, we validated seven microRNAs whose expression was shown to be higher in OLD tissue in comparison with the control and OSCC tissues.

A single nucleotide polymorphism in hsa‑miR‑146a is responsible for the development of bronchial hyperresponsiveness in response to intubation during general anesthesia

Bronchial hyperresponsiveness (BHR) is the most common clinical manifestation identified in asthmatic patients, and intubation is the major factor that stimulates the airway of patients receiving general anesthetic. In the present study, nitric oxide synthase 1 (NOS1) was identified as a target gene of micro (mi)R‑146a using in silico analysis and luciferase assay. Furthermore, the regulatory role of miR‑146a was demonstrated by the observation that the NOS1 expression level in pulmonary artery smooth muscle cells (PASMCs) transfected with miR‑146a mimics was significantly downregulated and the NOS1 expression level in PASMCs transfected with miR‑146a inhibitors was significantly upregulated. Additionally, it was identified that a polymorphism in pri‑miR‑146 interfered with mature processing and reduced the quantity of mature miRNA. To assess the association between the polymorphism and the development of BHR, 563 patients with basic pulmonary diseases, such as asthma, emphysema or bronchitis were enrolled in the present study. Each participant received a general anesthetic and the development of BHR was evaluated. The miR‑146a rs2910164 polymorphism CC genotype was identified to be significantly associated with a decreased risk of BHR in response to intubation when compared with the GG or GC genotype (odds ratio, 0.38; confidence interval, 0.18‑0.78). These findings indicate that the miR‑146a rs2910164 polymorphism is associated with a decrease risk of BHR, and the CC genotype increased the level of NOS1 expression, which was physiologically inhibited by wild‑type miR‑146a.

miR-146a is upregulated during retinal pigment epithelium (RPE)/choroid aging in mice and represses IL-6 and VEGF-A expression in RPE cells

PURPOSE

MicroRNA-146a (miR-146a) has been proposed as a marker for age-associated inflammation, or "inflammaging", acting as a negative regulator of cellular senescence and pro-inflammatory signaling pathways. However, the regulation and function of miR-146 during ocular aging remains unclear. Here we propose that miR-146 is regulated during aging of the retina and choroid, and functions in retinal pigment epithelial (RPE) cells to regulate key genes involved in inflammation and angiogenesis.

METHODS

The expression of miR-146a and miR-146b was examined in the neuroretina and RPE/choroid in mice aged from 2 months to 24 months. Then, the effect of synthetic miR-146a mimetic on IL-6 and VEGF-A expression was analyzed in RPE cells treated with and without TNF-α.

RESULTS

miR-146a and miR-146b was upregulated during aging of RPE/choroid but not neuroretina, supporting tissue-specific regulation of aging-related miRNAs in retinal tissues. Overexpression of miR-146a by miRNA mimics inhibited VEGF-A and TNF-α-induced IL-6 expression.

CONCLUSIONS

Elevation of miR-146a and miR-146b in the aging RPE/choroid but not neuroretina suggests a role for miRNAs in inflammaging in the RPE/choroid. miR-146a overexpression inhibits the expression IL-6 and VEGF-A in the RPE cells, supporting a negative feedback regulation mechanism by which inflammatory pathways may be dysregulated in RPE during aging.

Decreased epithelial and plasma miR-181b-5p expression associates with airway eosinophilic inflammation in asthma

BACKGROUND

Airway eosinophilic inflammation is a pivotal feature of asthma. Epithelial cells play critical roles in airway eosinophilia. We hypothesized that epithelial microRNAs (miRNAs) are involved in airway eosinophilia.

OBJECTIVE

This study investigated the associations between epithelial and plasma miR-181b-5p and airway eosinophilic inflammation, and the possible mechanism by which miR-181b-5p participates in eosinophilic inflammation.

METHODS

Epithelial miRNAs expression was profiled by miRNA array in eight subjects with asthma and four healthy controls. Epithelial miR-181b-5p expression was confirmed by quantitative PCR in the subjects for array experiment and another cohort including 21 subjects with asthma and 10 controls. Plasma miR-181b-5p was determined by quantitative PCR in 72 subjects with asthma and 35 controls. Correlation assays between epithelial and plasma miR-181b-5p expression and airway eosinophilia were performed. The target of miR-181b-5p, SPP1, was predicted by online algorithms and verified in BEAS-2B cells. The role of miR-181b-5p in epithelial proinflammatory cytokine expression was examined in an in vitro system.

RESULTS

Epithelial miR-181b-5p expression was decreased in subjects with asthma. Epithelial miR-181b-5p levels were inversely correlated with sputum and bronchial submucosal eosinophilia. Plasma miR-181b-5p was decreased and correlated with epithelial miR-181b-5p in subjects with asthma. There was a strong inverse correlation between plasma miR-181b-5p and airway eosinophilia in subjects with asthma. Plasma miR-181b-5p was increased after inhaled corticosteroids treatment. We verified that SPP1 is a target of miR-181b-5p. In human bronchial epithelial cells, miR-181b-5p regulated IL-13-induced IL-1β and CCL11 expression by targeting SPP1. Dexamethasone restored IL-13-induced miR-181b-5p down-regulation and suppressed IL-13-induced SPP1, IL-1β and CCL11 expression.

CONCLUSIONS AND CLINICAL RELEVANCE

Epithelial and plasma miR-181b-5p are potential biomarkers for airway eosinophilia in asthma. MiR-181b-5p may participate in eosinophilic airway inflammation by regulating proinflammatory cytokines expression via targeting SPP1.

Genetic and epigenetic factors in the regulation of the immune response

PURPOSE OF REVIEW

The review will update readers on research examining the influence of genetic variation and epigenetics on the immune system and whether genetic variation influences the outcome of critically ill children.

RECENT FINDINGS

Although there have been few recent studies examining the role of genetic variation in the severity of disease or outcome in critically ill children, studies in critically ill adults have been informative. For example, genetic variations in the genes coding for various components of the immune response, such as the Toll-like receptor 1, interleukin-1RA, proprotein convertase subtilisin/kexin type 9, adoponectin, nuclear factor erythroid 2-related factor 2, elafin, sphingosine 1-phosphate receptor 3, and sushi, von Willebrand factor type A, EGF and pentraxin domain containing 1 have been associated with various outcomes in critically ill adult populations. Many of the variants demonstrate functional consequences in the protein levels or activities. In critically ill children, there is an association with increased ICU length of stay in children with septic shock with one of the Toll-like receptor 1 variants.

SUMMARY

The degree of influence of host genetic variation in the outcome in critically ill children remains a much understudied area of research. However, it remains important because it may not only help identify children at risk for worse outcomes but it may provide insight into mechanisms of critical illnesses and novel therapies.

Emerging Roles for MicroRNAs in Perioperative Medicine

MicroRNAs (miRNAs) are small, non-protein-coding, single-stranded RNAs. They function as posttranscriptional regulators of gene expression by interacting with target mRNAs. This process prevents translation of target mRNAs into a functional protein. miRNAs are considered to be functionally involved in virtually all physiologic processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis, and inflammation. Many of these functions have important implications for anesthesiology and critical care medicine. Studies indicate that miRNA expression levels can be used to predict the risk for eminent organ injury or sepsis. Pharmacologic approaches targeting miRNAs for the treatment of human diseases are currently being tested in clinical trials. The present review highlights the important biological functions of miRNAs and their usefulness as perioperative biomarkers and discusses the pharmacologic approaches that modulate miRNA functions for disease treatment. In addition, the authors discuss the pharmacologic interactions of miRNAs with currently used anesthetics and their potential to impact anesthetic toxicity and side effects.

Resolution of Inflammation: What Controls Its Onset?

An effective resolution program may be able to prevent the progression from non-resolving acute inflammation to persistent chronic inflammation. It has now become evident that coordinated resolution programs initiate shortly after inflammatory responses begin. In this context, several mechanisms provide the fine-tuning of inflammation and create a favorable environment for the resolution phase to take place and for homeostasis to return. In this review, we focus on the events required for an effective transition from the proinflammatory phase to the onset and establishment of resolution. We suggest that several mediators that promote the inflammatory phase of inflammation can simultaneously initiate a program for active resolution. Indeed, several events enact a decrease in the local chemokine concentration, a reduction which is essential to inhibit further infiltration of neutrophils into the tissue. Interestingly, although neutrophils are cells that characteristically participate in the active phase of inflammation, they also contribute to the onset of resolution. Further understanding of the molecular mechanisms that initiate resolution may be instrumental to develop pro-resolution strategies to treat complex chronic inflammatory diseases, in humans. The efforts to develop strategies based on resolution of inflammation have shaped a new area of pharmacology referred to as "resolution pharmacology."

microRNA and Allergy

Allergy is a common hypersensitivity disorder of the immune system, which, along with other factors, is also subjected to regulation by microRNAs. The most common allergic diseases are allergic rhinitis, asthma, atopic dermatitis, and food allergy, which all are multifactorial and very heterogeneous conditions, highlighting the need for more individualized treatment techniques. More particular key questions in relation to allergic diseases are how microRNAs influence the differentiation, polarization, plasticity and functions of T helper and other immune cells, as well as the development of immune tolerance. In addition, microRNAs can affect allergic inflammation and tissue remodeling through their functions in epithelial and other tissue cells. Among immune system-related microRNAs, miR-21, miR-146a, and miR-155 are the most intensively studied and have convincingly been demonstrated to regulate immune responses and tissue inflammation in allergic diseases. Further characterization of microRNA functions is important, as similar to other conditions, the modulation of microRNA expression could potentially be used for therapeutic purposes in allergic diseases in the future. In addition, miRNAs could be implemented as biomarkers for endotyping complex allergic conditions.

Mouse Models of Primary Sjogren's Syndrome

Sjogren's syndrome (SjS) is a chronic autoimmune disorder characterized by immune cell infiltration and progressive injury to the salivary and lacrimal glands. As a consequence, patients with SjS develop xerostomia (dry mouth) and keratoconjunctivitis sicca (dry eyes). SjS is the third most common rheumatic autoimmune disorder, affecting 4 million Americans with over 90% of patients being female. Current diagnostic criteria for SjS frequently utilize histological examinations of minor salivary glands for immune cell foci, serology for autoantibodies, and dry eye evaluation by corneal or conjunctival staining. SjS can be classified as primary or secondary SjS, depending on whether it occurs alone or in association with other systemic rheumatic conditions, respectively. Clinical manifestations typically become apparent when the disease is relatively advanced in SjS patients, which poses a challenge for early diagnosis and treatment of SjS. Therefore, SjS mouse models, because of their close resemblance to the human SjS, have been extremely valuable to identify early disease markers and to investigate underlying biological and immunological dysregulations. However, it is important to bear in mind that no single mouse model has duplicated all aspects of SjS pathogenesis and clinical features, mainly due to the multifactorial etiology of SjS that includes numerous susceptibility genes and environmental factors. As such, various mouse models have been developed in the field to try to recapitulate SjS. In this review, we focus on recent mouse models of primary SjS xerostomia and describe them under three categories of spontaneous, genetically engineered, and experimentally induced models. In addition, we discuss future perspectives highlighting pros and cons of utilizing mouse models and current demands for improved models.

Airway smooth muscle inflammation is regulated by microRNA-145 in COPD

Chronic obstructive pulmonary disease (COPD) is a common, highly debilitating disease of the airways, primarily caused by smoking. Chronic inflammation and structural remodelling are key pathological features of this disease, in part caused by the aberrant function of airway smooth muscle (ASM) cells under the regulation of transforming growth factor (TGF)-β. miRNA are short, noncoding gene transcripts involved in the negative regulation of specific target genes, through their interactions with mRNA. Previous studies have proposed that mRNA-145 (miR-145) may interact with SMAD3, an important downstream signalling molecule of the TGF-β pathway. TGF-β was used to stimulate primary human ASM cells isolated from healthy nonsmokers, healthy smokers and COPD patients. This resulted in a TGF-β-dependent increase in CXCL8 and IL-6 release, most notably in the cells from COPD patients. TGF-β stimulation increased SMAD3 expression, only in cells from COPD patients, with a concurrent increased miR-145 expression. Regulation of miR-145 was found to be negatively controlled by pathways involving the MAP kinases, MEK-1/2 and p38 MAPK. Subsequent, overexpression of miR-145 (using synthetic mimics) in ASM cells from patients with COPD suppressed IL-6 and CXCL8 release, to levels comparable to the nonsmoker controls. Therefore, this study suggests that miR-145 negatively regulates pro-inflammatory cytokine release from ASM cells in COPD by targeting SMAD3.

Resolution of Inflammation: What Controls Its Onset?

An effective resolution program may be able to prevent the progression from non-resolving acute inflammation to persistent chronic inflammation. It has now become evident that coordinated resolution programs initiate shortly after inflammatory responses begin. In this context, several mechanisms provide the fine-tuning of inflammation and create a favorable environment for the resolution phase to take place and for homeostasis to return. In this review, we focus on the events required for an effective transition from the proinflammatory phase to the onset and establishment of resolution. We suggest that several mediators that promote the inflammatory phase of inflammation can simultaneously initiate a program for active resolution. Indeed, several events enact a decrease in the local chemokine concentration, a reduction which is essential to inhibit further infiltration of neutrophils into the tissue. Interestingly, although neutrophils are cells that characteristically participate in the active phase of inflammation, they also contribute to the onset of resolution. Further understanding of the molecular mechanisms that initiate resolution may be instrumental to develop pro-resolution strategies to treat complex chronic inflammatory diseases, in humans. The efforts to develop strategies based on resolution of inflammation have shaped a new area of pharmacology referred to as “resolution pharmacology.”

Extracellular microRNA-21 and microRNA-26a increase in body fluids from rats with antigen induced pulmonary inflammation and children with recurrent wheezing

Background

This study aims to find out whether extracellular miRNAs is implicated in recurrent childhood wheezing with asthmatic risk.

Methods

One hundred and forty children of Chinese Han population were recruited for this study. Plasma and intracellular miRNAs from children with recurrent wheezing and rats with antigen induced pulmonary inflammation (AIPI) were detected by using reverse transcription-quantitative PCR. Differential leukocytes in blood were automatically counted. Total IgE was detected by enzyme-linked immunosorbent assay. Clinical implication in diagnosis was evaluated using receiver operating characteristic curves.

Results

The increase of plasma miR-21 and miR-26a was screened out from 11 candidate miRNAs and validated in wheezing children. The level of expression for both miRNAs were comparable in different age and gender. Plasma miR-21 was more preferable to miR-26a and total IgE for diagnosis. Plasma miR-21 and miR-26a levels were not significantly correlated with various leukocyte counts or miRNA expression in blood cells. In acute and chronic AIPI rats, miR-21 levels increased in both plasma and lavaged lung compared with control. Moreover, circulating miR-21 and miR-26a levels were highly positively correlated with infiltrated cell counts in bronchoalveolar lavage fluid of AIPI rats.

Conclusions

Circulating miR-21 and miR-26a increase in wheezing children and AIPI rats. This not only manifests their strong clinical implication in recurrent childhood wheezing with asthma risk, but also provides novel insights into the role of extracellular miRNAs during development of airway inflammation and recurrent wheezing.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0216-2) contains supplementary material, which is available to authorized users.

Toll-Like Receptors in Cystic Fibrosis: Impact of Dysfunctional microRNA on Innate Immune Responses in the Cystic Fibrosis Lung

Toll-like receptors (TLRs) are a class of pattern recognition receptors that are particularly expressed in the sentinel and epithelial cells in the body, including the lung. They are central players in the innate immune system in response to microbial infection, and are the triggers of a complex pathway network that both promotes the inflammatory response and influences the adaptive immune response. These pathways are transiently and finely tuned by cellular factors, including a cell's microRNA response program. MicroRNAs are small, non-coding RNAs that specifically regulate gene expression. In this article, we review the disease-specific microRNA regulatory network of cystic fibrosis, a debilitating and ultimately fatal disease and, specifically, its effect on TLR signalling.