Role of miR-146a in regulation of the acute inflammatory response to monosodium urate crystals

Intermittent high altitude hypoxia induced liver and kidney injury leading to hyperuricemia

About 140 million people worldwide live at an altitude above 2500 m. Studies have showed an increase of the incidence of hyperuricemia among plateau populations, but little is known about the possible mechanisms. This study aims to assess the effects of high altitude on hyperuricemia and explore the corresponding mechanisms at the histological, inflammatory and molecular levels. This study finds that intermittent hypobaric hypoxia (IHH) exposure results in an increase of serum uric acid level and a decrease of uric acid clearance rate. Compared with the control group, the IHH group shows significant increases in hemoglobin concentration (HGB) and red blood cell counts (RBC), indicating that high altitude hyperuricemia is associated with polycythemia. This study also shows that IHH exposure induces oxidative stress, which causes the injury of liver and renal structures and functions. Additionally, altered expressions of organic anion transporter 1 (OAT1) and organic cation transporter 1 (OCT1) of kidney have been detected in the IHH exposed rats. The adenosine deaminase (ADA) expression levels and the xanthione oxidase (XOD) and ADA activity of liver of the IHH exposure group have significantly increased compared with those of the control group. Furthermore, the spleen coefficients, IL-2, IL-1β and IL-8, have seen significant increases among the IHH exposure group. TLR/MyD88/NF-κB pathway is activated in the process of IHH induced inflammatory response in joints. Importantly, these results jointly show that IHH exposure causes hyperuricemia. IHH induced oxidative stress along with liver and kidney injury, unusual expression of the uric acid synthesis/excretion regulator and inflammatory response, thus suggesting a potential mechanism underlying IHH-induced hyperuricemia.

Role of MicroRNAs in Inflammatory Joint Diseases: A Review

Inflammatory arthritis commonly initiates in the soft tissues lining the joint. This lining swells, as do the cells in it and inside the joint fluid, producing chemicals that induce inflammation signs such as heat, redness, and swelling. MicroRNA (miRNA), a subset of non-coding small RNA molecules, post-transcriptionally controls gene expression by targeting their messenger RNA. MiRNAs modulate approximately 1/3 of the human genome with their multiple targets. Recently, they have been extensively studied as key modulators of the innate and adaptive immune systems in diseases such as allergic disorders, types of cancer, and cardiovascular diseases. However, research on the different inflammatory joint diseases, such as rheumatoid arthritis, gout, Lyme disease, ankylosing spondylitis, and psoriatic arthritis, remains in its infancy. This review presents a deeper understanding of miRNA biogenesis and the functions of miRNAs in modulating the immune and inflammatory responses in the above-mentioned inflammatory joint diseases. According to the literature, it has been demonstrated that the development of inflammatory joint disorders is closely related to different miRNAs and their specific regulatory mechanisms. Furthermore, they may present as possible prognostic and diagnostic biomarkers for all diseases and may help in developing a therapeutic response. However, further studies are needed to determine whether manipulating miRNAs can influence the development and progression of inflammatory joint disorders.

Characterizations of microRNAs involved in the molecular mechanisms underlying the therapeutic effects of noni (Morinda citrifolia L.) fruit juice on hyperuricemia in mice

Background

Hyperuricemia is generally defined as the high level of serum uric acid and is well known as an important risk factor for the development of various medical disorders. However, the medicinal treatment of hyperuricemia is frequently associated with multiple side-effects.

Methods

The therapeutic effect of noni (Morinda citrifolia L.) fruit juice on hyperuricemia and the underlying molecular mechanisms were investigated in mouse model of hyperuricemia induced by potassium oxonate using biochemical and high-throughput RNA sequencing analyses.

Results

The levels of serum uric acid (UA) and xanthine oxidase (XOD) in mice treated with noni fruit juice were significantly decreased, suggesting that the noni fruit juice could alleviate hyperuricemia by inhibiting the XOD activity and reducing the level of serum UA. The contents of both serum creatinine and blood urine nitrogen of the noni fruit juice group were significantly lower than those of the model group, suggesting that noni fruit juice promoted the excretion of UA without causing deleterious effect on the renal functions in mice. The differentially expressed microRNAs involved in the pathogenesis of hyperuricemia in mice were identified by RNA sequencing with their target genes further annotated based on both Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases to explore the metabolic pathways and molecular mechanisms underlying the therapeutic effect on hyperuricemia by noni fruit juice.

Conclusion

Our study provided strong experimental evidence to support the further investigations of the potential application of noni fruit juice in the treatment of hyperuricemia.

Monosodium urate crystals alter the circadian clock in macrophages leading to loss of NLRP3 inflammasome repression: Implications for timing of the gout flare

Gout is caused by monosodium urate (MSU) crystal deposition within joints. This leads to acute episodes of inflammation ("gout flares") driven by NLRP3 inflammasome activation in macrophages. Gout flares are frequently present during late night/early morning. The reason for this timing is unclear. Recent evidence suggests the NLRP3 inflammasome is under circadian control. The purpose of this study was to determine whether MSU crystals cause changes in the circadian clock in macrophages leading to time-of-day differences in NLRP3 inflammasome activation. Levels of circadian clock components were measured in undifferentiated "monocytic" and PMA-differentiated "macrophagic" THP-1 cells cultured with/without MSU crystals. Caspase-1 activity was measured to assess NLRP3 inflammasome activity. MSU crystal exposure resulted in minimal effects on clock genes in THP-1 monocytes but BMAL1, CRY1, PER2, and REV-ERBα showed altered expression with reduced protein levels of BMAL1 and REV-ERBα in THP-1 macrophages. REV-ERBα activation or BMAL1 over-expression resulted in reduced MSU crystal-induced caspase-1 activity. BMAL1 knockdown resulted in a further increase in MSU crystal-induced caspase-1 activity, but only at times of day when BMAL1 levels were naturally high. MSU crystal-induced NLRP3 inflammasome activation was greatest at the time of day when BMAL1 levels were naturally low. MSU crystals alter the expression of circadian clock components in THP-1 macrophages leading to loss of BMAL1 and REV-ERBα-mediated repression of NLRP3 inflammasome activity and time-of-day differences in susceptibility to inflammasome activation. Our findings suggest that the nocturnal risk of gout flare is at least partially a consequence of altered circadian control of immune cell function.

Osteogenic Potential of Monosodium Urate Crystals in Synovial Mesenchymal Stem Cells

Background and Objectives: Deposits of monosodium urate (MSU) crystals due to increased levels of uric acid (UA) have been associated with bone formation and erosion, mainly in patients with chronic gout. The synovial membrane (SM) comprises several types of cells, including mesenchymal stem cells (SM-MSCs); however, it is unknown whether UA and MSU induce osteogenesis through SM-MSCs. Materials and Methods: Cultures of SM were immunotyped with CD44, CD69, CD90, CD166, CD105, CD34, and CD45 to identify MSCs. CD90+ cells were isolated by immunomagnetic separation (MACS), colony-forming units (CFU) were identified, and the cells were exposed to UA (3, 6.8, and 9 mg/dL) and MSU crystals (1, 5, and 10 μg/mL) for 3 weeks, and cellular morphological changes were evaluated. IL-1β and IL-6 were determined by ELISA, mineralization was assessed by alizarin red, and the expression of Runx2 was assessed by Western blot. Results: Cells derived from SM and after immunomagnetic separation were positive for CD90 (53 ± 8%) and CD105 (52 ± 18%) antigens, with 53 ± 5 CFU identified. Long-term exposure to SM-MSCs by UA and MSU crystals did not cause morphological damage or affect cell viability, nor were indicators of inflammation detected. Mineralization was observed at doses of 6.8 mg/dL UA and 5 μg/mL MSU crystals; however, the differences were not significant with respect to the control. The highest dose of MSU crystals (10 μg/mL) induced significant Runx2 expression with respect to the control (1.4 times greater) and SM-MSCs cultured in the osteogenic medium. Conclusions: MSU crystals may modulate osteogenic differentiation of SM-MSCs through an increase in Runx2.

Research progress on microRNA in gout

Gout is a common form of arthritis caused by the deposition of sodium urate crystals in the joints and tissues around them. MicroRNAs (miRNAs) are noncoding RNAs that have been shown to be involved in regulating the pathogenesis of gout through multiple cellular signaling pathways, which may be potential targets for the treatment of gout. In this review, we systematically discuss the regulatory roles of related miRNAs in gout, which will provide help for the treatment of gout and miRNAs is expected to become a potential biomarker for gout diagnosis.

Exploring RNA modifications, editing, and splicing changes in hyperuricemia and gout

Hyperuricemia and gout are two of the most common metabolic disorders worldwide; their incidence is increasing with changes in lifestyle, and they are correlated with many diseases, including renal and cardiovascular diseases. The majority of studies on hyperuricemia and gout have focused on the discovery of the associated genes and their functions and on the roles of monocytes and neutrophils in the development of gout. Virtually no studies investigating the epigenomics of gout disease or exploring the clinical significance of such research have been conducted. In this study, we observed that the expression of enzymes involved in RNA modifications or RNA editing was affected in uric acid (UA)- or monosodium urate (MSU)-treated cell lines. RNA alternative splicing and splicing factors were also affected by UA or MSU treatment. We used transcriptome sequencing to analyze genome-wide RNA splicing and RNA editing and found significant changes in RNA splicing and RNA editing in MSU- or UA-treated THP-1 and HEK293 cells. We further found significant changes of RNA modifications, editing, and splicing in patients with gout. The data indicate that RNA modifications, editing, and splicing play roles in gout. The findings of this study may help to understand the mechanism of RNA splicing and modifications in gout, facilitating the development of new diagnostic and therapeutic strategies.

Role of microRNA alternation in the pathogenesis of gouty arthritis

Gouty arthritis is a common inflammatory disease. The condition is triggered by a disorder of uric acid metabolism, which causes urate deposition and gout flares. MicroRNAs are a class of conserved small non-coding RNAs that bind to the 3' untranslated region (UTR) of mRNA and regulate the expression of a variety of proteins at the post-transcriptional level. In recent years, attention has been focused on the role of miRNAs in various inflammatory diseases, including gouty arthritis. It is thought that miRNAs may regulate immune function and inflammatory responses, thereby influencing the onset and progression of the disease. This article mainly reviewed the roles of miRNAs in the pathogenesis of gouty arthritis and prospected their potential as diagnostic and prognostic relevant biomarkers and as possible therapeutic targets.

The epigenome: key to understanding and predicting gout flares

Gout is a form of arthritis, resulting from an inflammatory reaction to the deposition of monosodium urate (MSU) crystals in the synovial fluid of the joint space. It is characterised by periods of acute inflammation in the affected joint, or joints (known as gout flares), separated by asymptomatic periods. There seems to be substantial overlap between environmental triggers of gout flares and common environmental modifiers (diet, pharmaceuticals, and stress) of epigenetic markers (DNA methylation, histone modifications, and ncRNA). Very few studies have looked at whether environment is influencing gout through epigenetic mechanisms. The pathogenesis of gouty inflammation is well understood but understanding the variation of response to hyperuricaemia in terms of gout flare initiation is less well known. In this review, we will examine the potential of epigenomics in understanding how gout flares may occur, both in terms of development of hyperuricaemia and the inflammatory response. Looking at the epigenome and its intersection with lifestyle could help identify new targets and strategies for effective management of gout flares.

The Role of microRNAs in Pulp Inflammation

The dental pulp can be affected by thermal, physical, chemical, and bacterial phenomena that stimulate the inflammatory response. The pulp tissue produces an immunological, cellular, and vascular reaction in an attempt to defend itself and resolve the affected tissue. The expression of different microRNAs during pulp inflammation has been previously documented. MicroRNAs (miRNAs) are endogenous small molecules involved in the transcription of genes that regulate the immune system and the inflammatory response. They are present in cellular and physiological functions, as well as in the pathogenesis of human diseases, becoming potential biomarkers for diagnosis, prognosis, monitoring, and safety. Previous studies have evidenced the different roles played by miRNAs in proinflammatory, anti-inflammatory, and immunological phenomena in the dental pulp, highlighting specific key functions of pulp pathology. This systematized review aims to provide an understanding of the role of the different microRNAs detected in the pulp and their effects on the expression of the different target genes that are involved during pulp inflammation.

MicroRNAs Involved in the Therapeutic Functions of Noni (Morinda citrifolia L.) Fruit Juice in the Treatment of Acute Gouty Arthritis in Mice Induced with Monosodium Urate

We investigated the functions of microRNAs in the therapeutic effects of noni (Morinda citrifolia L.) fruit juice on mouse models of acute gouty arthritis induced with monosodium urate (MSU). Compared with the model group (treated with MSU), mice in both the positive control group (treated with both MSU and colchicine) and noni fruit juice group (treated with MSU and noni fruit juice) showed a significantly decreased degree of paw swelling in 5 days, as well as the contents of two types of proinflammatory cytokines (i.e., NALP3 and TNF-α). Based on the next-generation sequencing technology, a total of 3896 microRNAs (234 known and 3662 novel) were identified in mice treated with noni fruit juice. A large amount of differentially expressed miRNAs were identified in the noni fruit juice group, suggesting the significant effects of noni fruit juice on the mice with acute gouty arthritis, while the different patterns of change in the numbers of both upregulated and downregulated miRNAs in both noni fruit juice and positive control groups indicated that the mice of acute gouty arthritis may be regulated by differential mechanisms between the treatments of noni fruit juice and colchicine. The target genes of microRNAs involved in the pathogenesis and pathology of acute gouty arthritis in mice were identified and further annotated by both Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Our results revealed the therapeutic effects of noni fruit juice on acute gouty arthritis in mice with a group of microRNAs involved in the pharmacological mechanisms of noni fruit juice, providing scientific evidence to support both the agricultural cultivation and pharmacological significance of noni plants.

Circulating microRNA alternations in primary hyperuricemia and gout

OBJECTIVES

MicroRNAs (miRNAs) are short single-stranded RNAs that play a role in the post-transcriptional regulation of gene expression. Their deregulation can be associated with various diseases, such as cancer, neurodegenerative, and immune-related diseases. The aim of our study was to compare miRNA levels in plasma that could potentially influence the progression of hyperuricemia to gout, since the mechanism of progression is still unclear.

METHODS

Total RNA, including miRNA, was isolated from the plasma of 45 patients with asymptomatic hyperuricemia, 131 patients with primary gout (including 16 patients having a gout attack), and 130 normouricemic controls. The expression of 18 selected miRNAs (cel-miR-39 and cel-miR-54 as spike-in controls, hsa-miR-16-5p and hsa-miR-25-3p as endogenous controls, hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-30a-3p, hsa-miR-30c-5p, hsa-miR-126-3p, hsa-miR-133a-3p, hsa-miR-142-3p, hsa-miR-143-3p, hsa-miR-146a-5p, hsa-miR-155-5p, hsa-miR-222-3p, hsa-miR-223-3p, hsa-miR-488-3p and hsa-miR-920) was measured using qPCR.

RESULTS

We found that hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-30c-5p, hsa-miR-142-3p, and hsa-miR-223-3p were significantly upregulated (p < 0.001) in the plasma of hyperuricemia and gout patients compared to normouricemic individuals. As part of the follow-up of our previous study, we found a negative correlation between hsa-miR-17-5p, hsa-miR-30c-5p, hsa-miR-126-3p, hsa-miR-142-3p, and hsa-miR-223-3p with plasma levels of chemokine MCP-1. Additionally, we found a positive correlation between CRP and plasma levels of hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-30c-5p, hsa-miR-126-3p, hsa-miR-142-3p, hsa-miR-146a-5p, hsa-miR-155-5p, hsa-miR-222-3p, and hsa-miR-223-3p. Five of those miRNAs (hsa-miR-126-3p, hsa-miR-142-3p, hsa-miR-146a-5p, hsa-miR-155-5p, and hsa-miR-222-3p) also had a positive correlation with serum creatinine and therefore a negative correlation with eGFR.

CONCLUSION

Five miRNAs were significantly upregulated in the plasma of patients with hyperuricemia and gout (and those during a gout attack) compared to normouricemic controls. We also found a correlation between the plasma levels of several miRNA and plasma levels of MCP-1, CRP, serum creatinine, and eGFR.

Elevation of miR-146a Inhibits BTG2/BAX Expression to Ameliorate Postoperative Cognitive Dysfunction Following Probiotics (VSL#3) Treatment

It has been reported that the gut microbiome modulates postoperative cognitive dysfunction (POCD), and that administration of probiotics (VSL#3) may effectively relieve POCD. In this study, we aimed to identify the underlying mechanism of VSL#3 in POCD. A mouse model of POCD was constructed in adult male C57BL/6 mice, which were then treated with VSL#3. VSL#3 exerted a protective role against POCD and resultant neuronal apoptosis. The expression of miR-146a was found to be downregulated in hippocampal tissues of POCD mice, while VSL#3 could restore its expression. Loss- and gain-function approaches were conducted to determine the roles of microRNA (miR)-146a, B-cell translocation gene 2 (BTG2), and Bcl-2-associated X protein (Bax) in post-operative effects on cognitive function and neuronal apoptosis. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) were measured to determine oxidative stress in brain tissue. The dual-luciferase reporter gene assay identified that miR-146a could target BTG2 and negatively regulate its expression. BTG2 knockdown suppressed neuronal apoptosis and contributed to shortened time of latency, prolonged time of mice spent in the target quadrant, and reduced oxidative stress through downregulating Bax expression. Finally, VSL#3 treatment upregulated the expression of miR-146a to block BTG2/Bax axis and consequently inhibited neuronal apoptosis and reduced oxidative stress in POCD mice. Taken together, the study suggested that miR-146a-mediated suppression of BTG2/Bax contributed to the protective role of probiotics treatment against POCD.

Autoinflammatory Features in Gouty Arthritis

In the panorama of inflammatory arthritis, gout is the most common and studied disease. It is known that hyperuricemia and monosodium urate (MSU) crystal-induced inflammation provoke crystal deposits in joints. However, since hyperuricemia alone is not sufficient to develop gout, molecular-genetic contributions are necessary to better clinically frame the disease. Herein, we review the autoinflammatory features of gout, from clinical challenges and differential diagnosis, to the autoinflammatory mechanisms, providing also emerging therapeutic options available for targeting the main inflammatory pathways involved in gout pathogenesis. This has important implication as treating the autoinflammatory aspects and not only the dysmetabolic side of gout may provide an effective and safer alternative for patients even in the prevention of possible gouty attacks.

MicroRNA-223 Suppresses IL-1β and TNF-α Production in Gouty Inflammation by Targeting the NLRP3 Inflammasome

Introduction: MicroRNA-223 (MiR-223) serves as an important regulator of inflammatory and immune responses and is implicated in several auto-inflammatory disorders. Here, we measured miR-223 expression in acute and intercritical gout patients, after which we used RAW264.7 macrophages transfected with a miR-223 mimic/inhibitor to determine the function of miR-223 in monosodium urate (MSU)-induced gouty inflammation.

Methods and Results: MiR-223 was detected among 122 acute gout patients (AG), 118 intercritical gout patients (IG), and 125 healthy subjects (HC). RAW264.7 macrophages were cultured and treated with MSU. Over-expression or under-expression of miR-223 was inducted in RAW264.7 macrophages to investigate the function of miR-223. Real-time quantitative PCR, ELISA and western blotting were used to determine the expression levels of miR-223, cytokines and the NLRP3 inflammasome (NLRP3, ASC, and caspase-1). MiR-223 expression was significantly decreased in the AG group in comparison with the IG and HC groups (p < 0.001, respectively). Up-regulated expression of miR-223 was observed after acute gout remission in comparison with that observed during gout flares in 30 paired cases (p < 0.001). The abundance of the NLRP3 inflammasome and cytokines was significantly increased after RAW264.7 macrophages were treated with MSU (p < 0.01, respectively), while that of miR-223 was significantly reduced (p < 0.01). Up-regulation of miR-223 decreased the concentrations of IL-1β and TNF-α, as well as the NLRP3 inflammasome expression (p < 0.01, respectively), while IL-37 and TGF-β1 levels were unchanged (p > 0.05, respectively). Under-expression of miR-223 increased the concentrations of IL-1β and TNF-α, as well as NLRP3 inflammasome expression (p < 0.01, respectively), while IL-37 and TGF-β1 levels were not influenced (p > 0.05, respectively).

Conclusion: These findings suggest that miR-223 provides negative feedback regulation of the development of gouty inflammation by suppressing production of IL-1β and TNF-α, but not by regulating IL-37 and TGF-β1. Moreover, miR-223 regulates cytokine production by targeting the NLRP3 inflammasome.

MiR-221-5p is involved in the regulation of inflammatory responses in acute gouty arthritis by targeting IL-1β

AIM

Gout is caused by the accumulation of deposited monosodium urate (MSU) crystals in the joints. Recent studies have shown that interleukin-1β (IL-1β) is a key inflammatory mediator of acute gouty arthritis (AGA), and its level is regulated by microRNAs (miRNAs). The purpose of this study was to study the role of miR-221-5p in the pathogenesis of AGA.

METHODS

One hundred patients with AGA and 94 healthy individuals were recruited. The expression of serum miR-221-5p was determined by quantitative real-time polymerase chain reaction. The receiver operating curve (ROC) was applied for diagnostic value analysis. A luciferase reporter assay was performed to confirm the interaction of miRNA and the 3'-untranslated region (UTR) of IL-1β. Enzyme-linked immunosorbent assay was used to detect serum and proinflammatory factors.

RESULTS

miR-221-5p had lower expression in the serum of AGA patients. The area under the curve was 0.884, the sensitivity was 82.0%, and the specificity was 80.9%. Serum miR-221-5p was negatively correlated with the expression levels of visual analog scale and IL-1β. Cell experiments showed that overexpression of miR-221-5p significantly inhibited the expression of inflammatory factors tumor necrosis factor-α, IL-8, and IL-1β, while down-regulation of miR-221-5p was the opposite. Luciferase analysis showed that IL-1β was the target gene of miR-221-5p.

CONCLUSIONS

This study confirmed that miR-221-5p regulates the production of inflammatory cytokines during the pathogenesis of AGA. These results suggested that miR-221-5p could be used as a potential therapeutic target for the treatment of AGA.

The Role of Noncoding RNAs in Gout

Over the past decade, noncoding ribonucleic acids (ncRNAs) have been shown to have crucial functional importance in health and disease. ncRNAs have been well studied and may be involved in the development of inflammatory arthritis, including gouty arthritis. Gout is also associated with metabolic pathway disorders, such as hyperuricemia, due to disturbed purine nucleotide metabolism or excretion of uric acid through the kidney. Moreover, their presence in the circulation has led to the idea that ncRNAs might serve as biomarkers for specific disease states to guide clinical decision-making. Therefore, we summarize the emerging evidence and review the current literature on the regulatory role of miRNAs and lncRNAs in gout pathophysiology. We further discuss the opportunities and challenges of ncRNAs as new blood-based biomarkers for future studies aimed at translation into clinical applications in the diagnosis and therapy of gout.

A MicroRNA Signature in Acute Coronary Syndrome Patients and Modulation by Colchicine

BACKGROUND

Circulating microRNAs (miRNAs) may play a pathogenic role in acute coronary syndromes (ACS). It is not yet known if miRNAs dysregulated in ACS are modulated by colchicine. We profiled miRNAs in plasma samples simultaneously collected from the aorta, coronary sinus, and right atrium in patients with ACS.

METHODS

A total of 396 of 754 miRNAs were detected by TaqMan real-time polymerase chain reaction from EDTA-plasma in a discovery cohort of 15 patients (n = 3 controls, n = 6 ACS standard therapy, n = 6 ACS standard therapy plus colchicine). Fifty-one significantly different miRNAs were then measured in a verification cohort of 92 patients (n = 13 controls, n = 40 ACS standard therapy, n = 39 ACS standard therapy plus colchicine). Samples were simultaneously obtained from the coronary sinus, aortic root, and right atrium.

RESULTS

Circulating levels of 30 of 51 measured miRNAs were higher in ACS standard therapy patients compared to controls. In patients with ACS, levels of 12 miRNAs (miR-17, -106b-3p, -191, -106a, -146a, -130a, -223, -484, -889, -425-3p, -629, -142-5p) were lower with colchicine treatment. Levels of 7 of these 12 miRNA were higher in ACS standard therapy patients compared to controls and returned to levels seen in control individuals after colchicine treatment. Three miRNAs suppressed by colchicine (miR-146a, miR-17, miR-130a) were identified as regulators of inflammatory pathways. MicroRNAs were comparable across sampling sites with select differences in the transcoronary gradient of 4 miRNA.

CONCLUSION

The levels of specific miRNAs elevated in ACS returned to levels similar to control individuals following colchicine. These miRNAs may mediate ACS (via inflammatory pathways) or increase post-ACS risk, and could be potentially used as biomarkers of treatment efficacy.

Converging Relationships of Obesity and Hyperuricemia with Special Reference to Metabolic Disorders and Plausible Therapeutic Implications

BACKGROUND

Obesity and hyperuricemia mutually influence metabolic syndrome. This study discusses the metabolic relationships between obesity and hyperuricemia in terms of pathophysiology, complications, and treatments.

METHODS

We searched for preclinical or clinical studies on the pathophysiology, complications, and therapy of obesity and hyperuricemia on the PubMed database.

RESULTS

In this systemic review, we summarized our searching results on topics of pathophysiology, complications and therapeutic strategy. In pathophysiology, we firstly introduce genetic variations for obesity, hyperuricemia and their relationships by genetic studies. Secondly, we talk about the epigenetic influences on obesity and hyperuricemia. Thirdly, we describe the central metabolic regulation and the role of hyperuricemia. Then, we refer to the character of adipose tissue inflammation and oxidative stress in the obesity and hyperuricemia. In the last part of this topic, we reviewed the critical links of gut microbiota in the obesity and hyperuricemia. In the following part, we review the pathophysiology of major complications in obesity and hyperuricemia including insulin resistance and type 2 diabetes mellitus, chronic kidney disease, cardiovascular diseases, and cancers. Finally, we recapitulate the therapeutic strategies especially the novel pharmaceutic interventions for obesity and hyperuricemia, which concurrently show the mutual metabolic influences between two diseases.

CONCLUSION

The data reviewed here delineate the metabolic relationships between obesity and hyperuricemia, and provide a comprehensive overview of the therapeutic targets for the management of metabolic syndromes.

Intranasal Administration of miR-146a Agomir Rescued the Pathological Process and Cognitive Impairment in an AD Mouse Model

Alzheimer’s disease (AD) is the most common cause of dementia and cannot be cured. The etiology and pathogenesis of AD is still not fully understood, the genetics is considered to be one of the most important factors for AD onset, and the identified susceptible genes could provide clues to the AD mechanism and also be the potential targets. MicroRNA-146a-5p (miR-146a) is well known in the regulation of the inflammatory response, and the functional SNP of miR-146a was associated with AD risk. In this study, using a noninvasive nasal administration, we discovered that a miR-146a agomir (M146AG) rescued cognitive impairment in the APP/PS1 transgenic mouse and alleviated the overall pathological process in the AD mouse model, including neuroinflammation, glia activation, Aβ deposit, and tau phosphorylation in hippocampi. Furthermore, the transcriptional analysis revealed that besides the effect of neuroinflammation, M146AG may serve as a multi-potency target for intervention in AD. In addition, Srsf6 was identified as a target of miR-146a, which may play a role in AD progression. In conclusion, our study supports that the nasal-to-brain pathway is efficient and operable for the brain administration of microRNAs (miRNAs), and that miR-146a may be a new potential target for AD treatment.

MiR-143-3p directly targets GLUT9 to reduce uric acid reabsorption and inflammatory response of renal tubular epithelial cells

GLUT9 is generally considered to be associated with the uric acid transport, which plays an important role in the regulation of serum uric acid level. In this study, the expression level of miR-143-3p was significantly decreased in hyperuricemia mice model group compared with the normal control by miRNA microarray, the same results were confirmed in the hyperuricemia patients and the healthy control group. It is predicted that GLUT9 may be the target gene of miR-143-3p by target scan and other net-software. GLUT9 as the downstream target gene of miR-143-3p was determinated by fluorescence enzyme activity assay. Western blotting and qRT-PCR indicated that the expression of GLUT9 in human renal tubular epithelial cells transfected with miR-143-3p mimics was significantly reduced. Meanwhile inflammatory factors IL-1β and MCP-1 significantly decreased. In conclusion, miR-143-3p can reduce uric acid reabsorption by inhibiting its downstream target gene GLUT9.

MicroRNAs as important regulators of the NLRP3 inflammasome

Inflammasomes are a group of cytosolic multi-protein signaling complexes that regulate maturation of the interleukin (IL)-1 family cytokines IL-1β and IL-18 through activation of inflammatory caspase-1. The NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome is the best characterized and consists of several key components that are assembled and activated in response to different endogenous and exogenous signals. The NLRP3 inflammasome is common to a number of human inflammatory diseases and its targeting may lead to novel anti-inflammatory therapy. NLRP3 inflammasome activation is tightly regulated by different mechanisms especially post-transcriptional modulation via microRNAs (miRNA). MicroRNAs are small endogenous noncoding RNAs that are 21-23 nucleotides in length and control the expression of various genes through binding to the 3'-untranslated regions of the respective mRNA and subsequent post-transcriptional regulation. MicroRNAs have recently been recognized as crucial regulators of the NLRP3 inflammasome. In this review, we summarize the current understanding of the role of miRNAs in the regulation of NLRP3 inflammasome complexes and their impact on the pathogenesis of inflammatory disease processes.

Rhein, An Anthraquinone Drug, Suppresses the NLRP3 Inflammasome and Macrophage Activation in Urate Crystal-Induced Gouty Inflammation

Rhein, an anthraquinone drug, is a widely used traditional Chinese medicine. Rhein is a major bioactive metabolite of diacerein which has been approved for treating osteoarthritis with a good safety profile in humans. Gouty arthritis is an inflammatory disease characterized by urate crystal-induced NLRP3 inflammasome activation with up-regulated caspase-1 protease and IL-1 β in macrophages. Inhibition of the NLRP3 inflammasome formation has been considered as a potential therapeutic avenue for treating or preventing many inflammatory diseases. This study aimed to evaluate the anti-inflammatory effects of rhein on gouty arthritis. Rhein within the physiological levels of humans showed no toxicity on the cell viability and differentiation, but significantly decreased the production of IL-1 β , TNF- α and caspase-1 protease in urate crystal-activated macrophages. Compared to medium controls, rhein at the therapeutic concentration (2.5 μ g/mL) effectively inhibited IL-1 β production by 47% ( P=0.002 ). Rhein did not affect the mRNA levels of CASP1, NLRP3 and ASC, but suppressed the protein expression and enzyme activity of caspase-1. Immunofluorescence confocal microscopy further revealed that rhein suppressed the aggregation of ASC speck and inhibited the formation of NLRP3 inflammasome. Rhein of 5 μ g/mL significantly decreased the ASC speck to 36% ( P=0.0011 ), and reduced the NLRP3 aggregates to 37.5% ( P=0.014 ). Our data demonstrate that rhein possesses pharmacological activity to suppress caspase-1 protease activity and IL-1 β production by interfering with the formation of NLRP3 multiprotein complex. These results suggest that rhein has therapeutic potential for treating NLRP3 inflammasome-mediated diseases such as gouty arthritis.

DICER1: A Key Player in Rheumatoid Arthritis, at the Crossroads of Cellular Stress, Innate Immunity, and Chronic Inflammation in Aging

Loss-of-function or knockout mouse models have established a fundamental role for the RNAse III enzyme DICER1 in development and tissue morphogenesis and/or homeostasis. These functions are currently assumed to result mainly from the DICER1-dependent biogenesis of microRNAs which exhibit important gene expression regulatory properties. However, non-canonical DICER1 functions have recently emerged. These include interaction with the DNA damage response (DDR) pathway and the processing of cytotoxic non-coding RNAs, suggesting that DICER1 might also participate in the regulation of major cellular processes through miRNA-independent mechanisms. Recent findings indicated that reduced Dicer1 expression, which correlates with worsened symptoms in mouse models of joint inflammation, is also noted in fibroblast-like synoviocytes (FLS) harvested from rheumatoid arthritis (RA) patients, as opposed to FLS cultured from biopsies of osteoarthritic patients. In addition, low DICER1 levels are associated with the establishment of cellular stress and its associated responses, such as cellular senescence. Senescent and/or stressed cells are associated with an inflammatory secretome (cytokines and chemokines), as well as with "find-me" and "eat-me" signals which will attract and activate the innate immune compartment (NK cells, macrophages, and neutrophils) to be eliminated. Failure of this immunosurveillance mechanism and improper restauration of homeostasis could lead to the establishment of a systemic and chronic inflammatory state. In this review, we suggest that reduced DICER1 expression contributes to a vicious cycle during which accumulating inflammation and premature senescence, combined to inadequate innate immunity responses, creates the appropriate conditions for the initiation and/or progression of autoimmune-autoinflammatory diseases, such as RA.

miR-155 is dispensable in monosodium urate-induced gouty inflammation in mice

BACKGROUND

The findings of a previous study by Jin et al. have shown that microRNA (miR)-155 was upregulated in patients with acute gouty arthritis and enhanced the proinflammatory cytokines. There is no direct evidence to support that miR-155 is indeed involved in monosodium urate (MSU)-induced inflammatory responses in vivo. The aim of this study was to investigate the role of miR-155 knock-out (KO) or knock-in (KI) mice in MSU-induced animal models to mimic acute gout.

METHODS

MiR-155 expression in cultured bone marrow-derived macrophages (BMDMs) from miR-155 KO, miR-155 KI, and wild-type (WT) mice treated with MSU crystals in vitro was detected by real-time quantitative polymerase chain reaction (qPCR). MiR-155 KO and WT mice were used to induce an acute gouty inflammatory response with MSU crystals including models of foot pad inflammation, ankle arthritis, air pouch inflammation, and peritonitis. Furthermore, the proinflammatory interleukin (IL)-1β levels in lavage fluids from air pouch and peritoneal cavity models were measured by enzyme-linked immunosorbent assay (ELISA), and tumor necrosis factor (TNF)-α production from BMDMs of miR-155 KI mice treated with MSU were measured by flow cytometry.

RESULTS

MiR-155 expression was quickly upregulated in BMDMs from WT mice following MSU treatment in vitro. In comparison with WT mice in vivo, the swelling index of miR-155 KO mice showed no significant difference in the murine foot pad and ankle arthritis models for the indicated different time points. There were similar changes in total cell numbers of lavage fluids in the air pouch and peritoneal cavity models between miR-155 KO and WT mice following MSU crystal injection. Moreover, the IL-1β levels of lavage fluids in the air pouch and peritonitis models from miR-155 KO mice were almost the same as those from WT mice. TNF-α levels were comparable from BMDMs treated with MSU crystals in vitro between miR-155 KI mice and WT mice.

CONCLUSIONS

MiR-155 is dispensable in MSU-induced gouty inflammation in mice. Deletion of miR-155 might not be an effective therapeutic approach to relieve the inflammation in acute gout.

Blocking fatty acid-fueled mROS production within macrophages alleviates acute gouty inflammation

Gout is the most common inflammatory arthritis affecting men. Acute gouty inflammation is triggered by monosodium urate (MSU) crystal deposition in and around joints that activates macrophages into a proinflammatory state, resulting in neutrophil recruitment. A complete understanding of how MSU crystals activate macrophages in vivo has been difficult because of limitations of live imaging this process in traditional animal models. By live imaging the macrophage and neutrophil response to MSU crystals within an intact host (larval zebrafish), we reveal that macrophage activation requires mitochondrial ROS (mROS) generated through fatty acid oxidation. This mitochondrial source of ROS contributes to NF-κB-driven production of IL-1β and TNF-α, which promote neutrophil recruitment. We demonstrate the therapeutic utility of this discovery by showing that this mechanism is conserved in human macrophages and, via pharmacologic blockade, that it contributes to neutrophil recruitment in a mouse model of acute gouty inflammation. To our knowledge, this study is the first to uncover an immunometabolic mechanism of macrophage activation that operates during acute gouty inflammation. Targeting this pathway holds promise in the management of gout and, potentially, other macrophage-driven diseases.

Mice with miR-146a deficiency develop severe gouty arthritis via dysregulation of TRAF 6, IRAK 1 and NALP3 inflammasome

BACKGROUND

MicroRNAs (miRNAs) serve as important regulators of inflammatory and immune responses and are implicated in several immune disorders including gouty arthritis. The expression of miR-146a is upregulated in the peripheral blood mononuclear cells of patients with inter-critical gout when compared to normouricemic and hyperuricemic controls and those patients with acute gout flares. However, the role of miR-146a in the development of gout remains unknown. Here, we used miR-146a knockout (KO) mice to test miR-146a function in a monosodium urate (MSU)-induced gouty arthritis model.

METHODS

The footpad or ankle joint of miR-146a KO and wild-type (WT) mice were injected with an MSU suspension to induce acute gouty arthritis. Bone marrow-derived macrophages (BMDMs) were stimulated with MSU and the gene expression of miR-146a; interleukin 1 beta (IL-1β); tumor necrosis factor-α (TNF-α); and the NACHT, LRR and PYD domains-containing protein 3 (NALP3) inflammasome was evaluated. TNF-α and IL-1β protein levels in BMDMs were assessed by fluorescence-activated cell sorting and western blot analyses. Gene and protein levels of TNF receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase (IRAK1), the targets of miR-146a, were also measured.

RESULTS

Significantly increased paw swelling and index and ankle joint swelling were observed in miR-146a KO mice compared to WT controls after MSU treatment. MiR-146a expression in BMDMs from WT mice was dramatically upregulated at 4 h following MSU stimulation. Additionally, the expression of IL-1β, TNF-α, and NALP3 was higher in BMDMs from miR-146a KO mice after exposure to MSU crystals compared to those from WT mice. Consistent with the observed gene expression, the IL-1β and TNF-α proteins were upregulated in miR-146a KO mice. Additionally quantitative RT-PCR and western blot demonstrated that TRAF6 and IRAK1 were dramatically upregulated in BMDMs from miR-146 KO mice compared to those from WT mice.

CONCLUSIONS

Collectively, these observations suggest that miR-146a provides negative feedback regulation of gouty arthritis development and lack of miR-146a enhances gouty arthritis via upregulation of TRAK6, IRAK-1, and the NALP3 inflammasome function.

miR-223-3p Inhibits Human Osteosarcoma Metastasis and Progression by Directly Targeting CDH6

Cadherin-6 (CDH6) is aberrantly expressed in cancer and closely associated with tumor progression. However, the functions of CDH6 in human osteosarcoma and the molecular mechanisms underlying CDH6 in osteosarcoma oncogenesis remain poorly understood. In this work, we assessed the role of CDH6 in human osteosarcoma and identified that the expression of CDH6 was closely related with the overall survival and poor prognosis of osteosarcoma patients. MicroRNAs (miRNAs) have been implicated as important epigenetic regulators during the progression of osteosarcoma. Using dual-luciferase reporter assays, we showed that miR-223-3p suppresses CDH6 expression by directly binding to the 3' UTR of CDH6. miR-223-3p overexpression significantly inhibited cell invasion, migration, growth, and proliferation by suppressing the CDH6 expression in vivo and in vitro. Besides, CDH6 overexpression in the miR-223-3p-transfected osteosarcoma cells effectively rescued the inhibition of cell invasion, migration, growth, and proliferation mediated by miR-223-3p. Additionally, Kaplan-Meier analysis suggests that the expression of miR-223-3p predicts favorable clinical outcomes for osteosarcoma patients. Moreover, the expression of miR-223-3p was downregulated in osteosarcoma patients and was negatively associated with the expression of CDH6. Collectively, these data highlight that miR-223-3p/CDH6 axis is an important novel pleiotropic regulator and could early predict the metastatic potential in human osteosarcoma treatments.

MicroRNA-302b negatively regulates IL-1β production in response to MSU crystals by targeting IRAK4 and EphA2

Background

Interleukin-1β (IL-1β) is a pivotal proinflammatory cytokine that is strongly associated with the inflammation of gout. However, the underlying mechanism through which the production of IL-1β is regulated has not been fully elucidated. Our previous work identified that miR-302b had an important immune regulatory role in bacterial lung infections. This study was conducted to evaluate the function of miR-302b on monosodium urate (MSU) crystal-induced inflammation and its mechanism.

Methods

The expression pattern and the immune-regulatory role of miR-302b were evaluated both in vitro and in vivo. The functional targets of miR-302b were predicted by bioinformatics, and then validated by genetic approaches. In addition, the clinical feature of miR-302b was analyzed using serum samples of patients with gouty arthritis.

Results

The extremely high expression of miR-302b was observed in both macrophages and mouse air membranes treated with MSU. Intriguingly, overexpression of miR-302b regulated NF-κB and caspase-1 signaling, leading to significantly attenuate MSU-induced IL-1β. By genetic analysis, miR-302b exhibited inhibitory function on IRAK4 and EphA2 by binding to their 3′-UTR regions. Corporately silencing IRAK4 and EphA2 largely impaired MSU-induced IL-1β protein production. Moreover, it was also found that miR-302b and EphA2 suppressed the migration of macrophages. Finally, it was observed that high expression of miR-302b was a general feature in patients with gouty arthritis.

Conclusions

These results suggest that miR-302b can regulate IL-1β production in MSU-induced inflammation by targeting NF-κB and caspase-1 signaling, and may be a potential therapeutic target for gouty arthritis.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1528-9) contains supplementary material, which is available to authorized users.

Circulating miR-146a/b correlates with inflammatory cytokines in COPD and could predict the risk of acute exacerbation COPD

The aim of this study was to investigate the predicting value of miR-146a/b for acute exacerbation chronic obstructive pulmonary disease (AECOPD) and COPD, and to explore their associations with inflammatory cytokines in AECOPD and stable COPD patients.One hundred six AECOPD, 122 stable COPD patients, and 110 health volunteers with age and sex matched to total COPD patients (AECOPD and stable COPD) were enrolled. Blood samples were collected from all participants. Relative expression of miR-146a/b was determined by real-time polymerase chain reaction. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), leukotriene B4 (LTB-4) expression in serum from AECOPD and stable COPD patients were assessed using commercial ELISA kit.Serum levels of miR-146a and miR-146b were down regulated in AECOPD patients compared with stable COPD patients and HCs. miR-146a and miR-146b are of good values for predicting the risk of AECOPD in HCs with AUC of 0.702 and 0.715. Additionally, miR-146a and miR-146b could distinguish AECOPD from stable COPD patients with AUC of 0.670 and 0.643. In AECOPD patients, levels of miR-146a in AECOPD patients were negatively associated with TNF-α, IL-6, IL-8, and LTE-4 expression. In stable COPD patients, miR-146a expressions were negatively correlated with TNF-α, IL-1β, IL-6, IL-8, and LTE-4 levels. And, the expressions of miR-146b in AECOPD patients were negatively associated with IL-1β and LTB-4 expression. While in stable COPD patients, miR-146b expressions were only negatively correlated with TNF-α level.In conclusion, miR-146a and miR-146b were negatively correlated with inflammatory cytokines, and could be promising biomarkers for predicting the risk of AECOPD in stable COPD patients and healthy individuals.

MicroRNA-488 and -920 regulate the production of proinflammatory cytokines in acute gouty arthritis

Background

Gout is considered one of the most painful acute conditions caused by deposition of monosodium urate (MSU) crystals within joints. Recent studies have shown that interleukin (IL)-1β is a key inflammatory mediator in acute gouty arthritis (GA), and its level is regulated by microRNAs (miRNAs). However, the molecular mechanisms of the regulation remain unclear.

Methods

A miRNA microarray was used to analyze the miRNA expression profiles in peripheral white blood cells (WBCs) of patients with GA. THP-1 cells were transfected with miRNA mimics, stimulated by MSU crystals, and then subjected to quantitative real-time polymerase chain reaction or Western blot analysis. Levels of IL-1β, IL-8, and tumor necrosis factor (TNF)-α in culture supernatants of THP-1 cells were measured by enzyme-linked immunosorbent assay. A luciferase reporter assay was conducted to confirm the interaction of miRNA and IL-1β 3′-untranslated regions (UTRs).

Results

Combining bioinformatics and miRNA expression profiles, we found five miRNAs (hsa-miR-30c-1-3p, hsa-miR-488-3p, hsa-miR-550a-3p, hsa-miR-663a, and hsa-miR-920) that possibly target IL-1β. Then, we demonstrated that miR-488 and miR-920 were significantly decreased in the WBCs of patients with GA and that MSU crystals could inhibit expression of miR-488 and miR-920. Upregulation of miR-488 and miR-920 could suppress MSU-induced IL-1β protein expression in THP-1 cells, but no significant difference in IL-1β messenger RNA levels was observed. Moreover, we found that miR-488 and miR-920 could directly target the 3′-UTR of IL-1β. Overexpression of miR-488 and miR-920 could significantly inhibit the gene and protein expression of IL-8 and TNF-α in MSU-induced THP-1 cells.

Conclusions

This study demonstrates the roles of miR-488 and miR-920 in regulating the production of proinflammatory cytokines in the pathogenesis of GA. These findings suggest that miR-488 and miR-920 could serve as potential therapeutic targets in the treatment of GA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1418-6) contains supplementary material, which is available to authorized users.

What makes gouty inflammation so variable?

Acute gout arthritis flares contribute dominantly to gout-specific impaired health-related quality of life, representing a progressively increasing public health problem. Flares can be complex and expensive to treat, partly due to the frequent comorbidities. Unmet needs in gout management are more pressing given the markedly increasing gout flare hospital admission rates. In addition, chronic gouty arthritis can cause joint damage and functional impairment. This review addresses new knowledge on the basis for the marked, inherent variability of responses to deposited urate crystals, including the unpredictable and self-limited aspects of many gout flares. Specific topics reviewed include how innate immunity and two-signal inflammasome activation intersect with diet, metabolism, nutritional biosensing, the microbiome, and the phagocyte cytoskeleton and cell fate. The paper discusses the roles of endogenous constitutive regulators of inflammation, including certain nutritional biosensors, and emerging genetic and epigenetic factors. Recent advances in the basis of variability in responses to urate crystals in gout provide information about inflammatory arthritis, and have identified potential new targets and strategies for anti-inflammatory prevention and treatment of gouty arthritis.

Molecular Pathophysiology of Gout

Three contradictory clinical presentations of gout have puzzled clinicians and basic scientists for some time: first, the crescendo of sterile inflammation in acute gouty arthritis; second, its spontaneous resolution, despite monosodium urate (MSU) crystal persistence in the synovium; and third, immune anergy to MSU crystal masses observed in tophaceous or visceral gout. Here, we provide an update on the molecular pathophysiology of these gout manifestations, namely, how MSU crystals can trigger the auto-amplification loop of necroinflammation underlying the crescendo of acute gouty arthritis. We also discuss new findings, such as how aggregating neutrophil extracellular traps (NETs) might drive the resolution of arthritis and how these structures, together with granuloma formation, might support immune anergy, but yet promote tissue damage and remodeling during tophaceous gout.

Hypertensive disorders during pregnancy and risk of type 2 diabetes in later life: a systematic review and meta-analysis

Many studies assessed the association between hypertensive disorders during pregnancy and risk of type 2 diabetes mellitus in later life, but contradictory findings were reported. A systemic review and meta-analysis was carried out to elucidate type 2 diabetes mellitus risk in women with hypertensive disorders during pregnancy. Pubmed, Embase, and Web of Science were searched for cohort or case-control studies on the association between hypertensive disorders during pregnancy and subsequent type 2 diabetes mellitus. Random-effect model was used to pool risk estimates. Bayesian meta-analysis was carried out to further estimate the type 2 diabetes mellitus risk associated with hypertensive disorders during pregnancy. Seventeen cohort or prospective matched case-control studies were finally included. Those 17 studies involved 2,984,634 women and 46,732 type 2 diabetes mellitus cases. Overall, hypertensive disorders during pregnancy were significantly correlated with type 2 diabetes mellitus risk (relative risk = 1.56, 95 % confidence interval 1.21-2.01, P = 0.001). Preeclampsia was significantly and independently correlated with type 2 diabetes mellitus risk (relative risk = 2.25, 95 % confidence interval 1.73-2.90, P < 0.001). In addition, gestational hypertension was also significantly and independently correlated with subsequent type 2 diabetes mellitus risk (relative risk = 2.06, 95 % confidence interval 1.57-2.69, P < 0.001). The pooled estimates were not significantly altered in the subgroup analyses of studies on preeclampsia or gestational hypertension. Bayesian meta-analysis showed the relative risks of type 2 diabetes mellitus risk for individuals with hypertensive disorders during pregnancy, preeclampsia, and gestational hypertension were 1.59 (95 % credibility interval: 1.11-2.32), 2.27 (95 % credibility interval: 1.67-2.97), and 2.06 (95 % credibility interval: 1.41-2.84), respectively. Publication bias was not evident in the meta-analysis. Preeclampsia and gestational hypertension are independently associated with substantially elevated risk of type 2 diabetes mellitus in later life.

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

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

Role of MicroRNAs in NAFLD/NASH

MicroRNAs (miRNAs) are highly conserved, small, 18-25 nucleotide, non-coding RNAs that regulate gene expression at the post-transcriptional level. Each miRNA can regulate hundreds of target genes, and vice versa each target gene can be regulated by numerous miRNAs, suggesting a very complex network and explaining how miRNAs play pivotal roles in fine-tuning essentially all biological processes in all cell types in the liver. Here, we summarize the current knowledge on the role of miRNAs in the pathogenesis and diagnosis of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) with an outlook to the broader aspects of metabolic syndrome. Furthermore, we discuss the role of miRNAs as potential biomarkers and therapeutic targets in NAFLD/NASH.

Induction of miR-146a by multiple myeloma cells in mesenchymal stromal cells stimulates their pro-tumoral activity

Mutual communication between multiple myeloma (MM) cells and mesenchymal stromal cells (MSC) plays a pivotal role in supporting MM progression. In MM, MSC exhibit a different genomic profile and dysregulated cytokine secretion compared to normal MSC, however the mechanisms involved in these changes are not fully understood. Here, we examined the miRNA changes in human MSC after culture with conditioned medium of MM cells and found 19 dysregulated miRNAs, including upregulated miR-146a. Moreover, exosomes derived from MM cells contained miR-146a and could be transferred into MSC. After overexpressing miR-146a in MSC, secretion of several cytokines and chemokines including CXCL1, IL6, IL-8, IP-10, MCP-1, and CCL-5 was elevated, resulting in the enhancement of MM cell viability and migration. DAPT, an inhibitor of the endogenous Notch pathway, was able to abrogate the miR-146a-induced increase of cytokines in MSC, suggesting the involvement of the Notch pathway. Taken together, our results demonstrate a positive feedback loop between MM cells and MSC: MM cells promote the increase of miR146a in MSC which leads to more cytokine secretion, which in turn favors MM cell growth and migration.

Expression Level of Urinary MicroRNA-146a-5p Is Increased in Patients With Bladder Cancer and Decreased in Those After Transurethral Resection

BACKGROUND

Bladder cancer is the most prevalent malignancy involving the urinary system and exhibits a markedly high recurrence rate. Therefore, reliable and noninvasive diagnostic and surveillance methods are desperately needed.

PATIENTS AND METHODS

Candidate microRNAs (miRNAs) were selected from the miRNAs that were differentially expressed in bladder cancer cell lines (T24 and RT4) compared to normal ureteral epithelial tissue using miRNA-microarray analysis. The candidate miRNAs were validated by quantitative reverse transcription polymerase chain reaction assay using voided urine samples.

RESULTS

We identified 3 miRNAs (miR-301b, -563, and -146a-5p) that demonstrated > 2-fold higher expression levels in cancer cell lines than in the normal ureteral epithelial tissue. Of these, only miR-146a-5p was consistently and significantly higher in urine samples from the patients with bladder cancer than in those from the normal individuals (P = .0014). The patients with high-grade tumors exhibited significantly higher urinary miR-146a-5p levels than those with low-grade tumors, and the patients with invasive tumors tended to show higher urinary miR-146a-5p levels than those with noninvasive tumors. Elevated urinary miR-146a-5p levels in patients with bladder cancer were decreased to the normal level after transurethral resection of the tumors (P = .0214).

CONCLUSION

Our study suggested that urinary miR-146a-5p might be useful as a new noninvasive diagnostic marker, therapeutic target, or anticancer agent for bladder cancer, as well as for increasing our understanding of cancer biology.

Effect of miR-146a/bFGF/PEG-PEI Nanoparticles on Inflammation Response and Tissue Regeneration of Human Dental Pulp Cells

Introduction. Inflammation in dental pulp cells (DPCs) initiated by Lipopolysaccharide (LPS) results in dental pulp necrosis. So far, whether there is a common system regulating inflammation response and tissue regeneration remains unknown. miR-146a is closely related to inflammation. Basic fibroblast growth factor (bFGF) is an important regulator for differentiation. Methods. To explore the effect of miR-146a/bFGF on inflammation and tissue regeneration, polyethylene glycol-polyethyleneimine (PEG-PEI) was synthesized, and physical characteristics were analyzed by dynamic light scattering and gel retardation analysis. Cell absorption, transfection efficiency, and cytotoxicity were assessed. Alginate gel was combined with miR-146a/PEG-PEI nanoparticles and bFGF. Drug release ratio was measured by ultraviolet spectrophotography. Proliferation and odontogenic differentiation of DPCs with 1 μg/mL LPS treatment were determined. Results. PEG-PEI prepared at N/P 2 showed complete gel retardation and smallest particle size and zeta potential. Transfection efficiency of PEG-PEI was higher than lipo2000. Cell viability decreased as N/P ratio increased. Drug release rate amounted to 70% at the first 12 h and then maintained slow release afterwards. Proliferation and differentiation decreased in DPCs with LPS treatment, whereas they increased in miR-146a/bFGF gel group. Conclusions. PEG-PEI is a promising vector for gene therapy. miR-146a and bFGF play critical roles in inflammation response and tissue regeneration of DPCs.

Dysregulated Serum MiRNA Profile and Promising Biomarkers in Dengue-infected Patients

OBJECTIVES

Pathological biomarkers and mechanisms of dengue infection are poorly understood. We investigated a new serum biomarker using miRNAs and performed further correlation analysis in dengue-infected patients.

METHODS

Expression levels of broad-spectrum miRNAs in serum samples from three patients with dengue virus type 1 (DENV-1) and three healthy volunteers were separately analyzed using miRNA PCR arrays. The expressions of the five selected miRNAs were verified by qRT-PCR in the sera of 40 DENV-1 patients and compared with those from 32 healthy controls. Receiver operating characteristic (ROC) curve and correlation analyses were performed to evaluate the potential of these miRNAs for the diagnosis of dengue infection.

RESULTS

MiRNA PCR arrays revealed that 41 miRNAs were upregulated, whereas 12 miRNAs were down-regulated in the sera of DENV-1 patients compared with those in healthy controls. Among these miRNAs, qRT-PCR validation showed that serum hsa-miR-21-5p, hsa-miR-590-5p, hsa-miR-188-5p, and hsa-miR-152-3p were upregulated, whereas hsa-miR-146a-5p was down-regulated in dengue-infected patients compared with healthy controls. ROC curves showed serum hsa-miR-21-5p and hsa-miR-146a-5p could distinguish dengue-infected patients with preferable sensitivity and specificity. Correlation analysis indicated that expression levels of serum hsa-miR-21-5p and hsa-miR-146a-5p were negative and positively correlated with the number of white blood cells and neutrophils, respectively. Functional analysis of target proteins of these miRNAs in silico indicated their involvement in inflammation and cell proliferation.

CONCLUSION

Dengue-infected patients have a broad "fingerprint" profile with dysregulated serum miRNAs. Among these miRNAs, serum hsa-miR-21-5p, hsa-miR-146a-5p, hsa-miR-590-5p, hsa-miR-188-5p, and hsa-miR-152-3p were identified as promising serum indicators for dengue infection.

Increased Expression of miR-146a in Children With Allergic Rhinitis After Allergen-Specific Immunotherapy

Purpose

MicroRNAs (miRs) were recently recognized to be important for immune cell differentiation and immune regulation. However, whether miRs were involved in allergen-specific immunotherapy (SIT) remains largely unknown. This study sought to examine changes in miR-146a and T regulatory cells in children with persistent allergic rhinitis (AR) after 3 months of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT).

Methods

Twenty-four HDM-sensitized children with persistent AR were enrolled and treated with SCIT (n=13) or SLIT (n=11) for 3 months. Relative miR-146a and Foxp3 mRNA expression, the TRAF6 protein level, and the ratio of post-treatment to baseline IL-10⁺CD4⁺ T cells between the SCIT and SLIT groups were examined in the peripheral blood mononuclear cells (PBMCs) of AR patients using quantitative reverse transcription polymerase chain reaction (qRT-PCR), flow cytometry, and Western blot analysis, respectively. Serum levels of IL-5 and IL-10 were determined using ELISA.

Results

After 3 months of SIT, both the TNSS and INSS scores were significantly decreased compared to the baseline value (P<0.01). The relative expression of miR-146a and Foxp3 mRNA was significantly increased after both SCIT and SLIT (P<0.01). The ratio of post-treatment to baseline IL-10⁺CD4⁺ T cells and the serum IL-10 level were significantly increased in both the SCIT and SLIT groups (P<0.01), whereas the TRAF6 protein level and serum IL-5 level were significantly decreased (P<0.01). No significant differences in these biomarkers were observed between the SCIT and SLIT groups.

Conclusions

Our findings suggest that miR-146a and its related biomarkers may be comparably modulated after both SCIT and SLIT, highlighting miR-146a as a potential therapeutic target for the improved management of AR.

miR-106a Is Downregulated in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B and Associated with Enhanced Levels of Interleukin-8

Aims. This study aimed to investigate miR-106a expression in peripheral blood mononuclear cells (PBMCs) of chronic hepatitis B (CHB) patients and to analyze the function of miR-106a. Materials and Methods. miR-106a expression levels in PBMCs from 40 healthy controls and 56 CHB patients were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The luciferase activity assays were used to determine whether miR-106a binds to 3′UTR of IL-8. miR-106a mimics and inhibitors were transfected into healthy PBMCs. IL-8 mRNA and protein levels were detected and determined by qRT-PCR and ELISA, respectively. Results. The qRT-PCR results suggested that the PBMC miR-106a levels were decreased in CHB patients. IL-8 was augmented in CHB patients and was inversely correlated with miR-106a levels. The luciferase activity assays indicated that IL-8 is a target of miR-106a. Exogenous expression of miR-106a could significantly repress IL-8 expression at both mRNA and protein levels in PBMCs, whereas miR-106a inhibitor had the opposite effects. Conclusions. This study suggested that miR-106a is downregulated in PBMCs of CHB patients and that miR-106a may play an important role in CHB by targeting IL-8.