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

Piper longum L. ameliorates gout through the MAPK/PI3K-AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Gout, a painful joint disease with a prevalence ranging from 0.86% to 2.2% in China over the past decade. Traditional medicine has long utilized the medicinal and edible Piper longum L. (PL) fruit spikes for treating gout and other joint conditions like rheumatoid arthritis. However, the exact mechanisms behind its effectiveness remain unclear.

AIM OF THE STUDY

This study aimed to investigate the potential of alcoholic extracts from PL fruit spikes as a safe and effective treatment for gout. We used a combined network pharmacology and experimental validation approach to evaluate the mechanisms behind the anti-gout properties of PL.

MATERIALS AND METHODS

UPLC-Q/TOF-MS analysis determined the major components of PL. Subsequently, network pharmacology analysis predicted potential molecular targets and related signaling pathways for the anti-gout activity of PL. Molecular docking simulations further explored the interactions between PL compounds and proteins and characterized the properties of potential bioactive secondary metabolites. Mouse models of air pouch inflammation and hyperuricemia were further established, and the anti-gout mechanism of PL was confirmed by examining the expression of proteins related to the MAPK and PI3K-AKT pathways in the tissue.

RESULTS

Our analysis revealed 220 bioactive secondary metabolites within PL extracts. Network pharmacology and molecular docking results indicated that these metabolites primarily combat gout by modulating the PI3K-AKT and MAPK signaling pathways. In vivo experiments have also proven that PL at a dose of 100 mg/kg can optimally reduce acute inflammation of gout and kidney damage caused by high uric acid. The anti-gout mechanism involves the PI3K-AKT/MAPK signaling pathway and its downstream NF-κB pathway.

CONCLUSION

This study provides compelling evidence for PL's therapeutic potential in gout management by modulating key inflammatory pathways. The findings offer a strong foundation for future clinical exploration of PL as a gout treatment option.

Non-coding RNAs as regulators of autophagy in chondrocytes: Mechanisms and implications for osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disease with multiple causative factors such as aging, mechanical injury, and obesity. Autophagy is a complex dynamic process that is involved in the degradation and modification of intracellular proteins and organelles under different pathophysiological conditions. Autophagy, as a cell survival mechanism under various stress conditions, plays a key role in regulating chondrocyte life cycle metabolism and cellular homeostasis. Non-coding RNAs (ncRNAs) are heterogeneous transcripts that do not possess protein-coding functions, but they can act as effective post-transcriptional and epigenetic regulators of gene and protein expression, thus participating in numerous fundamental biological processes. Increasing evidence suggests that ncRNAs, autophagy, and their crosstalk play crucial roles in OA pathogenesis. Therefore, we summarized the complex role of autophagy in OA chondrocytes and focused on the regulatory role of ncRNAs in OA-associated autophagy to elucidate the complex pathological mechanisms of the ncRNA-autophagy network in the development of OA, thus providing new research targets for the clinical diagnosis and treatment of OA.

Challenges and promise of targeting miRNA in rheumatic diseases: a computational approach to identify miRNA association with cell types, cytokines, and disease mechanisms

MicroRNAs (miRNAs) are small non-coding RNAs that alter the expression of target genes at the post-transcriptional level, influencing diverse outcomes in metabolism, cell differentiation, proliferation, cell survival, and cell death. Dysregulated miRNA expression is implicated in various rheumatic conditions, including ankylosing spondylitis (AS), gout, juvenile idiopathic arthritis (JIA), osteoarthritis (OA), psoriatic arthritis, rheumatoid arthritis (RA), Sjogren's syndrome, systemic lupus erythematosus (SLE) and systemic sclerosis. For this review, we used an open-source programming language- PowerShell, to scan the massive number of existing primary research publications on PubMed on miRNAs in these nine diseases to identify and count unique co-occurrences of individual miRNAs and the disease name. These counts were used to rank the top seven most relevant immuno-miRs based on their research volume in each rheumatic disease. Individual miRNAs were also screened for publication with the names of immune cells, cytokines, and pathological processes involved in rheumatic diseases. These occurrences were tabulated into matrices to identify hotspots for research relevance. Based on this information, we summarize the basic and clinical findings for the top three miRNAs - miR-146, miR-155, and miR-21 - whose relevance spans across multiple rheumatic diseases. Furthermore, we highlight some unique miRNAs for each disease and why some rheumatic conditions lack research in this emerging epigenetics field. With the overwhelming number of publications on miRNAs in rheumatic diseases, this review serves as a 'relevance finder' to guide researchers in selecting miRNAs based on the compiled existing knowledge of their involvement in disease pathogenesis. This approach applies to other disease contexts with the end goal of developing miRNA-based therapeutics.

Suppression of P2X7R by Local Treatment Alleviates Acute Gouty Inflammation

Objective

Gout is the most common inflammatory arthritis associated with interleukin-1β (IL-1β) accumulation during exacerbation. In this study, we aimed to clarify whether potassium channel antagonists attenuate local inflammation in mice with monosodium urate (MSU)-induced gout.

Methods

We cultured human macrophage THP-1 cells and evaluated the molecular levels of both IL-1β and potassium channels stimulated with MSU and/or potassium channel antagonists. Acute gout models were generated in IL-1β luciferase transgenic male mice using synovium-like subcutaneous air pouches with MSU injection. Their luciferase activities were monitored following potassium channel blocker treatment using the IVIS Spectrum CT imaging system. The lavages and tissues were extracted from their air pouches, followed by cell counting and pathological analysis.

Results

MSU stimulation increased the gene expression levels of pro-IL-1β, P2x7r and Kv1.3, whereas the expression of Kcnq1 was decreased in phorbol 12-myristate 13-acetate-induced THP-1 cells. Both high and low concentrations of the P2x7 receptor inhibitor adenosine 5'-triphosphate (ATP) derivative periodate oxidized ATP (oATP) decreased the production of IL-1β in the supernatant of THP-1 cells. The sixth hour was the peak time of IL-1β luciferase activity after MSU intervention in vivo. oATP ameliorated the synovial IL-1β luciferase activity, reduced inflammatory cell infiltration and alleviated the erosive damage in the cartilage.

Conclusion

The anti-inflammatory properties of potassium channel inhibitors, especially of oATP, might point to new strategies for local anti-inflammatory therapy for acute gout.

Nanoreporter for Real-Time Monitoring of Inflammasome Activity and Targeted Therapy

Inflammasome activation is associated with a myriad of inflammatory diseases. However, existing methods provides a limited understanding of spatiotemporal kinetics of inflammasome activation, with restricted scope for early detection of associated treatment efficacy. This limitation offers an opportunity for the development of biocompatible in-vivo inflammasome monitoring tools with translational prospects. To achieve this, they report developing a pair of lipid-based nanoparticle systems, a reporter nanoparticle consisting of a caspase-1 activatable probe alone, and a theranostic nanoparticle combining the probe with an inflammasome-inhibiting drug. This biocompatible platform enhances the probe's residence time in circulation by preventing its opsonization and allowing its sustained release over time. Their results demonstrate the specificity of reporter nanoparticles towards caspase-1 activity and provides early-on monitoring of inflammasome activation both in-vitro as well as in-vivo. Additionally, the delivery of disulfiram, an inflammasome-inhibiting drug, along with reporter probe using theranostic nanoparticles enables real-time tracking of treatment efficacy in the gouty-arthritis inflammatory model. In summary, they report an unparalleled pair of the inflammasome-associated reporter and theranostic platforms suited not only for diagnostic applications but can also detect inflammasome-targeted treatment efficiency in real-time. These findings establish two novel, sensitive nanotools for non-invasive evaluation of inflammasome-targeted immunotherapy.

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.

Calycosin represses AIM2 inflammasome-mediated inflammation and pyroptosis to attenuate monosodium urate-induced gouty arthritis through NF-κB and p62-Keap1 pathways

Gouty arthritis is an inflammatory disease induced by monosodium urate (MSU), and is closely related to the activation of inflammasomes. Calycosin plays an anti-inflammatory role in arthritis. This study explored the mechanism of Calycosin in MSU-induced gouty arthritis. MSU-induced gouty arthritis mouse models with or without treatment of Calycosin were established, and physiological and pathological indicators were determined. Similarly, peripheral blood mononuclear cells (PBMCs) and THP-1 macrophages were used in vitro. Lactate dehydrogenase (LDH) was tested. The degree of centrifugal infiltration was detected by immunofluorescence. ELISA and quantitative reverse-transcription polymerase chain reaction were conducted to determine the levels of inflammatory factors. Immunohistochemistry, immunofluorescence, and flow cytometry were utilized to detect the content of caspase-1. Protein expressions of NF-κB-, p62-Keap1 pathway-, and pyroptosis-related factors were examined by western blot. In MSU-induced mouse models, calycosin increased mechanical hyperalgesia but decreased the swelling index of the mouse knee joint in a time-dependent manner. MSU treatment increased inflammatory cells and LysM-eGFP⁺ neutrophils recruitment in vivo, and promoted the LDH content in vitro, and meanwhile, calycosin reversed the aforementioned effects of MSU. In addition, calycosin repressed the release of inflammatory factors, promoted p62 level and diminished the levels of AIM2, caspase-1, ASC, IL-1β, Keap1, Cleaved GSDMD, and Cleaved caspase-1 and phosphorylation of p65 and IκBα in MSU-induced mouse or cell models. Furthermore, AIM2 silencing also inhibited MSU-induced inflammation and pyroptosis. Collectively, calycosin may inhibit AIM2 inflammasomes-mediated inflammation and pyroptosis through NF-κB and p62-Keap1 pathways, ultimately playing a protective role in gouty arthritis.

MicroRNAs and Efferocytosis: Implications for Diagnosis and Therapy

About 10-100 billion cells are generated in the human body in a day, and accordingly, 10-100 billion cells predominantly die for maintaining homeostasis. Dead cells generated by apoptosis are also rapidly engulfed by macrophages (Mθs) to be degraded. In case of the inefficient engulfment of apoptotic cells (ACs) via Mθs, they experience secondary necrosis and thus release intracellular materials, which display damage-associated molecular patterns (DAMPs) and result in diseases. Over the last decades, researchers have also reflected on the significant contribution of microRNAs (miRNAs) to autoimmune diseases through the regulation of Mθs functions. Moreover, miRNAs have shown intricate involvement with completely adjusting basic Mθs functions, such as phagocytosis, inflammation, efferocytosis, tumor promotion, and tissue repair. In this review, the mechanism of efferocytosis containing "Find-Me", "Eat-Me", and "Digest-Me" signals is summarized and the biogenesis of miRNAs is briefly described. Finally, the role of miRNAs in efferocytosis is discussed. It is concluded that miRNAs represent promising treatments and diagnostic targets in impaired phagocytic clearance, which leads to different diseases.

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.

MiR-192-5p suppresses M1 macrophage polarization via epiregulin (EREG) downregulation in gouty arthritis

Gouty arthritis (GA) is a chronic inflammatory disease characterized by the deposition of monosodium urate (MSU) crystals within joints. MiR-192-5p is shown to be low-expressed in GA patients. However, the potential mechanism involving miR-192-5p in GA remains unclear. In the current study, a significant reduction in miR-192-5p and an increase in epiregulin (EREG) were observed in serum of GA patients, suggesting that miR-192-5p and EREG were involved in the pathogenic process of GA. A mouse GA model was established via 0.5 mg/20 μL MSU crystal administration. To investigate the effect of miR-192-5p on GA, mice were injected with miR-192-5p agomir or NC agomir before modeling. We found that miR-192-5p overexpression induced by miR-192-5p agomir reduced EREG expression, attenuated ankle joint swelling and synovial inflammatory cell infiltration and improved bone erosion in MSU-induced GA mice. MiR-192-5p decreased CD16/32⁺ (M1 marker) macrophages, but increased CD206 (M2 marker) expression in synovium of GA models. In vitro, RAW264.7 macrophages were stimulated with miR-192-5p mimic or NC mimic under IFNγ plus LPS-stimulated M1 polarization condition. MiR-192-5p reduced the release of inflammatory cytokines TNF-α and IL-1β, decreased iNOS expression, and inhibited CD16/32 expression, indicating the blockade of M1 macrophage activation. Luciferase reporter system revealed the target interaction between miR-192-5p and EREG. Further rescue experiments demonstrated that EREG overexpression partly reversed the inhibitory role of miR-192-5p on M1 macrophage polarization manifested by elevated iNOS and CD16/32 levels. Collectively, miR-192-5p ameliorates inflammatory response in GA by inhibiting M1 macrophage activation via inhibiting EREG protein.

Effects of Stephania hainanensis alkaloids on MSU-induced acute gouty arthritis in mice

BACKGROUND

Gout is initiated by the precipitation of monosodium urate (MSU) crystals within the joints and soft tissues, and it can eventually cause acute or chronic arthritis. MSU crystals trigger, amplify, and maintain a strong inflammatory response through promoting proinflammatory activity. In this study, the therapeutic effects of Stephania hainanensis (S. hainanensis) total alkaloid (SHA) were tested and evaluated on MSU-induced acute gouty arthritis in a mouse model.

METHODS

After oral administration of SHA (10 or 20 mg/kg) or the antigout medicine colchicine (0.5 mg/kg) once daily for 3 consecutive days, MSU crystals suspended in saline (2.5 mg/50 μl) were intradermally injected into the right paw of the mice. Then, SHA and colchicine were administered for another 2 days. During this period, swelling of the ankle and clinical scores were measured at 12, 24, and 48 h postinjection. After the mice were euthanized, inflammatory cytokine expression and paw tissue inflammation-related gene and protein expression, and a histopathological analysis was performed.

RESULTS

SHA had obvious therapeutic effects on MSU-induced acute gouty arthritis in mice. SHA alleviated ankle swelling and inhibited the production of cytokines, such as IL-1β and TNF-α. In addition, NLRP3, Caspase-1 and IL-1β, which are activated by MSU were also suppressed by SHA. The histological evaluation showed that SHA relieved the infiltration of inflammation around the ankle.

CONCLUSIONS

These results suggest that SHA is capable of anti-inflammatory activities and may be useful for treating gouty arthritis.

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.

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.

Combined effects of MSU crystals injection and high fat-diet feeding on the establishment of a gout model in C57BL/6 mice

OBJECTIVE

Gout is characterized by inflammatory arthritis with hyperuricaemia and deposition of monosodium urate (MSU) crystals in the joints. Several animal models have been proposed based on MSU crystals injection or high-fat diet feeding; however, neither hyperuricaemia model nor acute gout model can effectively reflect clinical features of gout. This study aimed to assess the effectiveness of a compound gout model induced by the combination of MSU crystals injection and high-fat diet feeding.

METHODS

The compound gout model was induced by high-fat diet feeding per day and the intraplantar injection of MSU crystals (1 mg) into the footpad of each mouse every 10 days. Serum uric acid, foot swelling and pain analyses were performed at days 22, 32 and 42. Gout inflammation, serum proinflammatory cytokines and gut microbiota analyses were performed only at day 42.

RESULTS

Compared to hyperuricaemia model or acute gout model, the compound gout model showed little advantages of elevating serum uric acid, causing foot swelling and gout inflammation, while it caused more severe serum inflammation and gut microbiota dysbiosis. Severe serum inflammation in the compound gout model could be reflected by the increased levels of IL-1α, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, IFN-γ, KC, MCP-1 and MIP-1β. In addition, the compound gout model induced more alterations in the gut microbiota, including increasing levels of Desulfovibrio and Parasutterella.

CONCLUSION

The injection of MSU and feed of high-fat diet have a combined effect on elevating serum inflammation and causing gut microbiota disorders in the process of establishing a gout model.

Silencing of Gasdermin D by siRNA-Loaded PEI-Chol Lipopolymers Potently Relieves Acute Gouty Arthritis through Inhibiting Pyroptosis

Gasdermin D (GSDMD) plays a causal role in NOD-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis eruption, which has been regarded as a potential therapeutic target for pyroptosis-related diseases including acute gouty arthritis. In the present study, the synthesized PEI-Chol (cholesterol grafted polyethylenimine) was assembled with GSDMD small interfering RNA (siRNA) to form PEI-Chol/siGSDMD polyplexes, which provided high transfection efficiency for siRNA-mediated GSDMD knockdown. Then we evaluated the effect of GSDMD siRNA-loaded PEI-Chol on inflammatory cascades in bone-marrow-derived macrophages (BMDMs) and acute gouty arthritis animal models under MSU exposure. When accompanied by pyroptosis blockade and decreased release of interleukin-1 beta (IL-1β), NLRP3 inflammasome activation was also suppressed by GSDMD knockdown in vivo and in vitro. Moreover, in MSU-induced acute gouty arthritis mice, blocking GSDMD with siRNA significantly improved ankle swelling and inflammatory infiltration observed in histopathological analysis. Furthermore, investigation using a mouse air pouch model verified the effect of siGSDMD-loaded PEI-Chol on pyroptosis of recruited macrophages and related signaling pathways in response to MSU. These novel findings exhibited that GSDMD knockdown relieved acute gouty arthritis through inhibiting pyroptosis, providing a possible therapeutic approach for MSU-induced acute gouty arthritis molecular therapy using PEI-Chol as a nucleic acid delivery carrier.

Functional Regulation of Macrophage Phenotypes by MicroRNAs in Inflammatory Arthritis

Inflammatory arthritis including rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) exhibit the shared feature of changes in activation and polarization of circulating monocytes and tissue macrophages. Numerous microRNAs (miRs) have been found to have key functions in regulating inflammation and macrophage polarization. Although there is increasing interest in the roles of miRs in both RA and JIA, less is known regarding how miRs relate to functional properties of immune cells, including monocytes and macrophages. Interestingly, miRs can function both to promote inflammatory phenotypes and pro-inflammatory polarization, as well as through negative-feedback loops to limit inflammation. Here, we review the functional roles of several miRs in macrophages in inflammatory arthritis, with a particular focus on vivo effects of miR alteration in experimental arthritis. We also consider how current efforts to target miRs clinically could modify functional monocyte and macrophage polarization in vivo, and serve as novel therapies for diseases such as RA and JIA.

Overexpression of microRNA‑155 alleviates palmitate‑induced vascular endothelial cell injury in human umbilical vein endothelial cells by negatively regulating the Wnt signaling pathway

The present study aimed to investigate the effect of microRNA155 (miR-155) on palmitate-induced vascular endothelial cell injury in human umbilical vein endothelial cells (HUVECs) via the regulation of the Wnt signaling pathway. HUVECs were treated with 0.1 mM palmitate. After transfection with mimic, antagomir or the Wnt pathway inhibitor XAV939, HUVECs were divided into six treatment groups: Control, palmitate, mimic + palmitate, mimic + palmitate + XAV939, antagomir + palmitate, antagomir + palmitate + XAV939. miR-155 expression was detected using reverse transcription-quantitative PCR. The expression levels of the Wnt signaling pathway-related factors β-catenin and Cyclin D, and the inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), were detected using western blot analysis. MTT and Transwell assays were used to detect the proliferation and migration of cells, respectively. Apoptosis and reactive oxygen species (ROS) levels were determined using flow cytometry. The localization of β-catenin in cells was determined by immunofluorescence. Palmitate reduced the expression level of miR-155 in HUVECs. In palmitate-induced HUVECs, overexpression of miR-155 promoted cell proliferation, reduced the levels of apoptosis, downregulated IL-6 and TNF-α expression, and reduced ROS levels. Inhibition of the Wnt signaling pathway enhanced the anti-endothelial cell injury effect caused by the overexpression of miR-155 in palmitate-induced HUVECs, thereby promoting proliferation, reducing apoptosis, downregulating the levels of inflammatory factors and reducing ROS levels. In summary, overexpression of miR-155 inhibited palmitate-induced apoptosis, ROS production and levels of inflammatory factors, and promoted the proliferation of HUVECs by negatively regulating the Wnt signaling pathway. This present study provides a theoretical basis for the prevention and treatment of cardiovascular diseases associated with endothelial cell injury.

miRNA-335-5p relieves chondrocyte inflammation by activating autophagy in osteoarthritis

AIMS

Osteoarthritis (OA) is a chronic and degenerative joint disease prevalent in the elderly, which is characterized by hypertrophy and reactive hyperplasia of articular cartilage. Autophagy has been reported to inhibit inflammation and reduce chondrocyte apoptosis in OA. As the microRNA (miRNA)-335-5p has been linked to both inflammation and autophagy, this study aimed to investigate its potential role in regulating autophagy during the pathogenesis of OA.

MAIN METHODS

Quantitative real-time PCR (qRT-PCR) was used to detect miRNA-335-5p expression in normal and OA human chondrocytes. Following transfection of human OA chondrocytes with double-stranded miRNA-335-5p mimic/inhibitor, qRT-PCR, western blotting, and immunofluorescence were used to determine expression levels of the inflammatory mediators IL-1β, IL-6, and TNF-α, and the autophagic markers Beclin-1, autophagy-related protein 5 (ATG5), and ATG7. The autophagy inhibitor 3-methyladenine (3-MA) was used to link the anti-inflammatory effects of miRNA-335-5p to autophagy.

KEY FINDINGS

The expression of miRNA-335-5p was significantly lower in OA chondrocytes than in normal chondrocytes. Transfection of human OA chondrocytes with the miRNA-335-5p mimic led to a remarkable increase in viability, a significant increase in autophagy-related factors, and a reduction in inflammatory mediators. Importantly, treatment of miRNA-335-5p-overexpressing OA chondrocytes with the autophagy inhibitor 3-MA restored the expression of inflammatory mediators.

SIGNIFICANCE

We conclude that miRNA-335-5p can significantly alleviate inflammation in human OA chondrocytes by activating autophagy. Therefore, miRNA-335-5p has potential for future use in the clinical diagnosis and treatment of OA.