MiR-206 regulates the Th17/Treg ratio during osteoarthritis

Therapeutic application of regulatory T cell in osteoarthritis

Regulatory T cells (Tregs) are the specific T cell population that suppress inflammatory immunity. Independent of their inhibitory activities, Tregs exhibit unique capacity to repair tissue damage. Rapid progresses are made in the processing and engineering of Tregs for clinical applications. Tregs have been used in the treatment of autoimmune diseases, transplantation rejection and graft-versus-host disease. Osteoarthritis is one of the major diseases that affect at least 600 million people worldwide. Osteoarthritis is characterized by physical erosion of cartilage, accompanied with chronic and low-grade inflammation. Tregs possess abilities to increase osteoclast differentiation and bone resorption, repair bone physical damage, and increase bone mass. Tregs are therefore candidate therapeutics for osteoarthritis for both inflammation resolution and tissue repairing. In this review, we will summarize the recent development in using Tregs in immunotherapy, and the potential of using Tregs in osteoarthritis.

Immune cells differentiation in osteoarthritic cartilage damage: friends or foes?

Osteoarthritis (OA) is a chronic disease primarily characterized by degenerative changes in articular cartilage and synovitis, for which there are currently no targeted or curative therapies available in clinical practice. In recent years, the in-depth analysis of OA using single-cell sequencing and immunomics technologies has revealed the presence of multiple immune cell subsets, as well as different differentiation states within the same subset, in OA. Through immune-immune and immune-joint tissue interactions, these cells collectively promote or inhibit the progression of arthritis. This complex immune network, where "friends and foes coexist," has made targeted therapeutic strategies aimed at directly eliminating immune cells challenging, highlighting the urgent need for a detailed review of the composition, distribution, functional heterogeneity, therapeutic potential, and potential risks of immune subsets within the joint. Additionally, the similarities and differences between OA and rheumatoid arthritis (RA) in terms of diagnosis and immunotherapy need to be precisely understood, in order to draw lessons from or reject RA-based immunotherapies. To this end, this review summarizes the major triggers of inflammation in OA, the differentiation characteristics of key immune cell subsets, and compares the similarities and differences between OA and RA in diagnosis and treatment. It also outlines the current immunomodulatory strategies for OA and their limitations. Furthermore, we provide a detailed and focused discussion on immune cells that act as "friends or foes" in arthritis, covering the M1/M2 polarization of macrophages, functional heterogeneity of neutrophils, unique roles of dendritic cells at different maturation states, the balance between pro-inflammatory T cells and regulatory T cells (Tregs), and the diverse functions of B cells, plasma cells, and regulatory B cells (Bregs) in OA. By interpreting the roles of these immune cells, this review clarifies the dynamic changes and interactions of immune cells in OA joints, providing a theoretical foundation for more precise targeted interventions in future clinical practice.

Adipose-derived mesenchymal stem cells combined with platelet-rich plasma are superior options for the treatment of osteoarthritis

BACKGROUND

There is currently no definitive treatment for osteoarthritis. We examined the therapeutic effects and underlying mechanisms of platelet-rich plasma (PRP) and adipose-derived mesenchymal stem cells (ADSCs), individually or in combination, in a rat model of anterior cruciate ligament-induced degenerative osteoarthritis (OA) of the knee. This study seeks to advance clinical approaches to OA treatment.

METHODS

Eight- to nine-week-old male Sprague-Dawley (SD) rats were randomly assigned to two groups: (1) a normal control group (Group A) and (2) a model group. The control group received no treatment. The model group underwent treatment and was further subdivided into six groups: Group B (an injury control group), Group C (high-dose ADSCs), Group D (PRP combined with high-dose ADSCs), Group E (low-dose ADSCs), Group F (PRP combined with low-dose ADSCs), and Group G (PRP alone). PRP and/or ADSCs were administered via intra-articular injection on Days 7, 37, and 67 post-surgery. Daily observations recorded activity levels and behavior, while weight changes were monitored weekly. Digital radiography (DR) was conducted on Days 30, 60, and 90 post-surgery to assess joint surface and contour alterations. Histopathological examination and inflammatory factor analysis were performed on cartilage and synovial tissue.

RESULTS

No abnormal reactions were observed in any rats, and body weights increased as expected (P > 0.05). Significant differences in knee swelling rates and Wakitani scores were observed between Groups A and B (P < 0.01). Knee swelling rates also differed significantly between Group B and Groups C-G (P < 0.01). Wakitani scores decreased on Days 60 and 90 in Groups C-G. TNF-α and IL-1β expression levels were significantly higher in Group B compared to Group A (P < 0.05). Expression levels of these genes were significantly lower in Groups C-G than in Group B (P < 0.05).

CONCLUSIONS

Repeated intra-articular injections of PRP and ADSCs alleviated inflammation and pain, promoted tissue repair, and modulated immune responses in rats with surgically induced OA. The combination of PRP and ADSCs demonstrated enhanced therapeutic efficacy, suggesting its potential as a treatment option for OA.

Synovial mast cells and osteoarthritis: Current understandings and future perspectives

Osteoarthritis (OA) is a prevalent joint disease worldwide that significantly impacts the quality of life of individuals, particularly those in middle-aged and elderly populations. OA was initially considered as non-inflammatory arthritis, but recent studies have identified a substantial number of immune responses in OA, leading to the recognition of inflammation as a key factor in its pathogenesis. An increasing number of studies have found that mast cell (MC) and MC-secreted inflammatory mediators and cytokines are notably increased in the synovial fluid of OA patients, indicating a potential association between MCs and the onset and progression of synovial inflammation. The present review aims to summarize the significance and mechanism of MCs in the pathogenesis of OA. Meanwhile, we also discuss the clinical potential of using MCs as therapeutic target for OA therapy. Modulating the activities of MCs or the mediators of MCs in the synovial fluid inflammatory microenvironment will be promising new options for the treatment of OA.

Exploration of the molecular mechanism of Wufu Yin in the treatment of knee osteoarthritis based on network pharmacology and experimental validation

Wufu Yin (WFY) exhibits significant clinical effectiveness in knee osteoarthritis (KOA) treatment, yet its therapeutic mechanisms are still unclear. This study aimed to explore the active ingredients and potential mechanism of WFY in the treatment of KOA. The network pharmacology-based approach was adopted to investigate the underlying mechanism of WFY in treating KOA. Molecular docking analysis was performed using Auto Vina software. An in vitro model of KOA inflammation was established by inducing chondrocyte cultures with interleukin-1 beta (IL-1β). Cell viability was quantified through the cell counting kit-8 assay, inflammatory cytokine levels were measured via ELISA, and protein expressions were assessed by Western blot analysis. A total of 225 active ingredients and 265 targets of WFY were identified, of which 88 were identified as potential targets against KOA. Enrichment analysis showed that these targets were associated with oxidative stress, cell proliferation and apoptosis, and inflammatory response, and were involved in the regulation of Th17 cell differentiation, IL-17 signaling pathway, tumor necrosis factor signaling pathway, and other signaling pathways. Topology analysis showed that PTGS2, NOS2, ESR11, PPARG, and MAPK14 had higher degree values and were key targets of WFY in the treatment of KOA. Molecular docking analysis showed that these key targets and active ingredients had low binding energies, indicating that they had potential binding activity. Furthermore, IL-1β-induced elevation of inflammatory cytokines, PTGS2 protein expression, and phosphorylated p38/p38 ratios in chondrocytes were significantly attenuated upon WFY intervention. Our study systematically elucidated the pharmacological basis and molecular mechanism underlying WFY's therapeutic effects in KOA, substantiating its ability to suppress inflammation and regulate PTGS2 expression and p38 phosphorylation.

Exploring the mechanism of action of Modified Simiao Powder in the treatment of osteoarthritis: an in-silico study

Introduction

Osteoarthritis (OA) is the most common form of arthritis and the leading musculoskeletal disorders in adults. Modified Simiao Powder (MSMP) has been widely used in the treatment of OA with remarkable clinical ecaciousness.

Objective

This study aimed to elucidate underlying mechanisms of MSMP in OA by employing network pharmacology, molecular docking, and molecular dynamics simulations, due to the unclear mode of action.

Methods

Bioinformatic analysis was used to evaluate the major chemical constituents of MSMP, determine prospective target genes, and screen genes associated with OA. Network pharmacology methods were then applied to identify the crucial target genes of MSMP in OA treatment. Further analyses included gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. These key targets within the pertinent pathways was further confirmed by molecular docking, binding energy evaluation, and molecular dynamics simulations.

Results

Network pharmacology analysis identified an MSMP component-target-pathway network comprising 11 central active compounds, 25 gene targets, and 12 biological pathways.

Discussion

These findings imply that the therapeutic effects of MSMP was potentially mediated by targeting several pivotal genes, such as androgen receptor (AR), NFKB1, AKT1, MAPK1, and CASP3, and regulating some pathways, including lipid metabolism and atherosclerosis, the AGE-RAGE signaling pathway in diabetic complications, the PI3K-Akt signaling pathway, fluid shear stress, atherosclerosis, and Kaposi's sarcoma-associated herpesvirus infection. Molecular docking assessments demonstrated that these compounds of MSMP, such as berberine, kaempferol, quercetin, and luteolin, exhibit high binding anities to AR and AKT1. Molecular dynamics simulations validated the interactions between these compounds and targets.

Conclusion

The therapeutic effect of MSMP likely attributed to the modulation of multiple pathways, including lipid metabolism, atherosclerosis, the AGE-RAGE signaling pathway, and the PI3K-Akt signaling pathway, by the active components such as berberine, kaempferol, luteolin, and quercetin. Especially, their actions on target genes like AR and AKT1 contribute to the therapeutic benefits of MSMP observed in the treatment of OA.

STUDY ON THE ROLE AND MECHANISM OF MICRORNA-650/WNT1 IN THE REPAIR OF ARTICULAR CARTILAGE INJURY

Objectives

Osteoarthritis (OA) is a degenerative disease associated with chondrocyte injury. This study investigated the dysregulation of microRNA-650 (miR-650) in cartilage tissues of patients with OA. Its function and mechanism were also investigated in OA cell models.

Methods

miR-650 levels were examined in 15 OA cartilage tissues and ten healthy cartilage tissues. SW1353 cells were used for cell function experiments and IL-1β was applied to the cells to mimic OA conditions in vitro. Cell functions such as proliferation, apoptosis, and inflammation were detected. The downstream target gene of miR-650 was identified and confirmed by bioinformatic analysis and luciferase activity assay. Rescue experiments were performed to verify the mechanism.

Results

Suppressed expression of miR-650 was tested in patients with OA and cell models. Overexpression of miR-650 increased cell proliferation but suppressed apoptosis and inflammation of SW1353. As the target gene of miR-650, WNT1 overexpression counteracted the role of miR-650 in the function of SW1353.

Conclusion

miR-650 can protect against articular cartilage injury in OA by targeting WNT1. Level of Evidence I, Experimental Study.

A Sustained-Release Butyrate Tablet Suppresses Ex Vivo T Helper Cell Activation of Osteoarthritis Patients in a Double-Blind Placebo-Controlled Randomized Trial

Degenerative joint disease osteoarthritis (OA) is characterized by the degeneration of cartilage, synovial inflammation and low-grade systemic inflammation in association with microbial dysbiosis and intestinal barrier defects. Butyrate is known for its anti-inflammatory and barrier protective effects and might benefit OA patients. In a double-blind placebo-controlled randomized trial, the effects of four to five weeks of oral treatment with sustained-release (SR) butyrate tablets (600 mg/day) on systemic inflammation and immune function were studied in hand OA patients. Serum markers for systemic inflammation and lipopolysaccharide (LPS) leakage were measured and ex vivo stimulation of whole blood or peripheral blood mononuclear cells (PBMCs) was performed at baseline and after treatment. Butyrate treatment did not affect the serum markers nor the cytokine release of ex vivo LPS-stimulated whole blood or PBMCs nor the phenotype of restimulated monocytes. By contrast, butyrate treatment reduced the percentage of activated T helper (Th) cells and the Th17/Treg ratio in αCD3/CD28-activated PBMCs, though cytokine release upon stimulation remained unaffected. Nevertheless, the percentage of CD4+IL9+ cells was reduced by butyrate as compared to the placebo. In both groups, the frequency of Th1, Treg, Th17, activated Th17, CD4+IFNγ+ and CD4+TNFα+ cells was reduced. This study shows a proof of principle of some immunomodulatory effects using a SR butyrate treatment in hand OA patients. The inflammatory phenotype of Th cells was reduced, as indicated by a reduced percentage of Th9 cells, activated Th cells and improved Th17/Treg balance in ex vivo αCD3/CD28-activated PBMCs. Future studies are warranted to further optimize the butyrate dose regime to ameliorate inflammation in OA patients.

The role of Th/Treg immune cells in osteoarthritis

Osteoarthritis (OA) is a prevalent clinical condition affecting the entire joint, characterized by its multifactorial etiology and complex pathophysiology. The onset of OA is linked to inflammatory mediators produced by the synovium, cartilage, and subchondral bone, all of which are closely tied to cartilage degradation. Consequently, OA may also be viewed as a systemic inflammatory disorder. Emerging studies have underscored the significance of T cells in the development of OA. Notably, imbalances in Th1/Th2 and Th17/Treg immune cells may play a crucial role in the pathogenesis of OA. This review aims to compile recent advancements in understanding the role of T cells and their Th/Treg subsets in OA, examines the immune alterations and contributions of Th/Treg cells to OA progression, and proposes novel directions for future research, including potential therapeutic strategies for OA.

Exosome-derived microRNAs: emerging players in vitiligo

Exosome-derived microRNAs (miRNAs) are biomacromolecules and nanoscale extracellular vesicles originating from intracellular compartments that are secreted by most cells into the extracellular space. This review examines the formation and function of exosomal miRNAs in biological information transfer, explores the pathogenesis of vitiligo, and highlights the relationship between exosomal miRNAs and vitiligo. The aim is to deepen the understanding of how exosomal miRNAs influence immune imbalance, oxidative stress damage, melanocyte-keratinocyte interactions, and melanogenesis disorders in the development of vitiligo. This enhanced understanding may contribute to the development of potential diagnostic and therapeutic options for vitiligo.

Immunoengineering Biomaterials for Musculoskeletal Tissue Repair across Lifespan

Musculoskeletal diseases and injuries are among the leading causes of pain and morbidity worldwide. Broad efforts have focused on developing pro-regenerative biomaterials to treat musculoskeletal conditions; however, these approaches have yet to make a significant clinical impact. Recent studies have demonstrated that the immune system is central in orchestrating tissue repair and that targeting pro-regenerative immune responses can improve biomaterial therapeutic outcomes. However, aging is a critical factor negatively affecting musculoskeletal tissue repair and immune function. Hence, understanding how age affects the response to biomaterials is essential for improving musculoskeletal biomaterial therapies. This review focuses on the intersection of the immune system and aging in response to biomaterials for musculoskeletal tissue repair. The article introduces the general impacts of aging on tissue physiology, the immune system, and the response to biomaterials. Then, it explains how the adaptive immune system guides the response to injury and biomaterial implants in cartilage, muscle, and bone and discusses how aging impacts these processes in each tissue type. The review concludes by highlighting future directions for the development and translation of personalized immunomodulatory biomaterials for musculoskeletal tissue repair.

The role of microRNA-142a in Toxoplasma gondii infection-induced downregulation of Foxp3: implications for adverse pregnancy outcomes

BACKGROUND

Toxoplasma gondii (T. gondii) is capable of infecting nearly all warm-blooded animals and approximately 30% of the global population. Though most infections are subclinical in immunocompetent individuals, congenital contraction can lead to severe consequences such as spontaneous abortion, stillbirth, and a range of cranio-cerebral and/or ocular abnormalities. Previous studies reported that T. gondii-infected pregnancy mice unveiled a deficit in both the amount and suppressive functions of regulatory T (Treg) cells, accompanied with reduced levels of forkhead box p3 (Foxp3). Recently, accumulative studies have demonstrated that microRNAs (miRNAs) are, to some extent, relevant to T. gondii infection. However, the link between alterations in miRNAs and downregulation of Foxp3 triggered by T. gondii has been only sporadically studied.

METHODS

Quantitative reverse transcription polymerase chain reaction (RT-qPCR), protein blotting and immunofluorescence were employed to evaluate the impact of T. gondii infection and antigens on miRNA transcription and Foxp3 expression. Dual-luciferase reporter gene assays were performed to examine the fluorescence activity in EL4 cells, which were transfected with recombinant plasmids containing full-length/truncated/mutant microRNA-142a-3p (miR-142a) promoter sequence or wild type/mutant of Foxp3 3' untranslated region (3' UTR).

RESULTS

We found a pronounced increase in miR-142a transcription, concurrent with a decrease in Foxp3 expression in T. gondii-infected mouse placental tissue. Similarly, comparable findings have been experimentally confirmed through the treatment of EL4 cells with T. gondii antigens (TgAg) in vitro. Simultaneously, miR-142a mimics attenuated Foxp3 expression, whereas its inhibitors markedly augmented Foxp3 expression. miR-142a promoter activity was elevated upon the stimulation of T. gondii antigens, which mitigated co-transfection of mutant miR-142a promoter lacking P53 target sites. miR-142a mimics deceased the fluorescence activity of Foxp3 3' untranslated region (3' UTR), but it did not affect the fluorescence activity upon the co-transfection of mutant Foxp3 3' UTR lacking miR-142a target site.

CONCLUSION

In both in vivo and in vitro studies, a negative correlation was discovered between Foxp3 expression and miR-142a transcription. TgAg enhanced miR-142a promoter activity to facilitate miR-142a transcription through a P53-dependent mechanism. Furthermore, miR-142a directly targeted Foxp3 3' UTR, resulting in the downregulation of Foxp3 expression. Therefore, harnessing miR-142a may be a possible therapeutic approach for adverse pregnancy caused by immune imbalances, particularly those induced by T. gondii infection.

High gastrointestinal digestive stability endows chondroitin sulfate-soluble undenatured type II collagen complex with high activity: Improvement of osteoarthritis in rats

Previously, we prepared a chondroitin sulfate-soluble undenatured type II collagen complex (CS-SC II) with low salt content. This paper further explored the differences between CS-SC II and SC II in terms of gastrointestinal digestive characteristics and osteoarthritis (OA) improvement. In vitro and in vivo experiments showed that the gastric digestive stability of CS-SC II was high under both pH 2.0 and pH 3.0, the α1 chain and triple helix structure of type II collagen retained >60 %. However, SC II had high gastric digestive stability only under pH 3.0. Furthermore, intestinal digestion had little effect on α1 chains of CS-SC II and SC II, and distribution experiments showed that they might exert their biological activities in the intestine. CS-SC II had obvious improvement in OA rats at 1.0 mg/kg/d, that is, the joint swelling was significantly reduced and the weight-bearing ratio of the right hind limb was increased to 49 %, which was close to that of 4.0 mg/kg/d SC II. The wear of articular cartilage, Mankin and OARSI scores of rats in CS-SC II group were significantly reduced. The effects of low-dose CS-SC II on the proportion of regulatory T cells (Treg), mRNA expression of OA key biomarkers (Il6, Ccl7, MMP-3 and MMP13) and signaling pathway genes (NF-κB, AKT or AMPKα) were comparable to those of high-dose SC II. These results showed that CS-SC II might have greater potential to improve OA at a lower dose than SC II due to its high gastrointestinal digestive stability at a wide range of pH conditions.

The role of miRNAs in T helper cell development, activation, fate decisions and tumor immunity

T helper (Th) cells are central members of adaptive immunity and comprise the last line of defense against pathogen infection and malignant cell invasion by secreting specific cytokines. These cytokines then attract or induce the activation and differentiation of other immune cells, including antibody-producing B cells and cytotoxic CD8+ T cells. Therefore, the bidirectional communication between Th cells and tumor cells and their positioning within the tumor microenvironment (TME), especially the tumor immune microenvironment (TIME), sculpt the tumor immune landscape, which affects disease initiation and progression. The type, number, and condition of Th cells in the TME and TIME strongly affect tumor immunity, which is precisely regulated by key effectors, such as granzymes, perforins, cytokines, and chemokines. Moreover, microRNAs (miRNAs) have emerged as important regulators of Th cells. In this review, we discuss the role of miRNAs in regulating Th cell mediated adaptive immunity, focusing on the development, activation, fate decisions, and tumor immunity.

The Promotion of Humoral Immune Responses in Humans via SOCS1-Mediated Th2-Bias Following SARS-CoV-2 Vaccination

The effectiveness of SARS-CoV-2 vaccines varies among individuals. During the COVID-19 global pandemic, SARS-CoV-2 infection showed significant Th1 characteristics, suggesting that the immune disorder and production of SARS-CoV-2 antibodies may be related to Th1/Th2 bias. However, the molecular mechanisms underlying Th1/Th2 bias effects on host immune responses to viruses remain unclear. In this study, the top three subjects with the highest and lowest changes in anti-SARS-CoV-2 antibodies after receiving three doses of SARS-CoV-2 vaccination were selected and defined as the elevated group (E) and the control group (C), respectively. Peripheral blood was collected, single-cell sequencing was performed before and after the third dose of the SARS-CoV-2 vaccine, and the changes in T cell clusters were analyzed. Compared with the C group, the Treg pre-vaccination proportion was lower in E, while the post-vaccination proportion was higher, suggesting that Tregs may be crucial in this process. Differential analysis results of Tregs between the two groups revealed that differentially expressed genes (DEGs) were significantly enriched in the IL4 pathway. Correlation analysis between DEGs and serum antibody showed that the expression of NR4A2, SOCS1, and SOCS3 in Tregs was significantly correlated with serum antibodies, suggesting that the immune response in E group changed to Th2 bias, thereby promoting host humoral immune responses. On the other hand, antibody-related genes SOCS1 and NR4A2, as well as lnc-RNA MALAT1 and NEAT1, were highly expressed in the CD4-MALAT1 subclusters. In summary, our study revealed that Th2 bias promotes humoral immune responses in humans by increasing SOCS1 in T cells after SARS-CoV-2 vaccination. Moreover, NR4A2, SOCS1, MALAT1, and NEAT1 were identified as the potential key biomarkers or treatment targets for enhanced SARS-CoV-2 antibody production by influencing the Th1/Th2 balance in T cells. Our findings have important implications for population stratification and tailored therapeutics for more effective SARS-CoV-2 vaccines.

Differences between soluble and insoluble undenatured type II collagen in improving osteoarthritis in rats and their potential mechanisms

Our previous research showed that soluble (SC II) and insoluble (IC II) undenatured type II collagen had significant differences during gastrointestinal digestion in vitro, and SC II exposed more type II collagen with triple helix structure. However, the differences in their in vivo digestive characteristics, improvement on osteoarthritis (OA), and possible mechanisms have not been elucidated. The aim of this study was to explore these issues. After oral administration of SC II and IC II, the joint swelling of OA rats significantly reduced, and the weight bearing ratio of right hind limb significantly increased, especially in SC II group (raised to 48%). The Mankin and OARSI scores decreased by 35% and 48% in SC II group, respectively. SC II and IC II increased the mRNA expression of anti-inflammatory factors and the proportion of regulatory T cells (Treg). Importantly, type II collagen released by IC II during in vivo gastrointestinal digestion was far less than SC II, which explained the higher ability of SC II to induce immune tolerance in small intestine than IC II. Bioinformatics analysis showed that the differential genes between model and control were significantly enriched in PI3K/AKT, PPAR and AMPK signalling pathways, and 24 hub genes were analyzed. SC II significantly down-regulated the mRNA expression of Il6, Ccl7, NF-κB, AKT and up-regulated the mRNA expression of Scd1. These results showed that SC II was superior to IC II in improving OA by inducing immune tolerance and could regulate key biomarkers and signalling pathways in OA rats.

MicroRNAs in idiopathic inflammatory myopathies: state-of-the-art and future perspectives

PURPOSE OF REVIEW

Idiopathic inflammatory myopathies (IIMs) are a group of rare autoimmune disorders characterized by muscle weakness and inflammation. MicroRNAs (miRNAs) are the main class of small noncoding RNAs regulating a wide range of physiological and pathological processes and play a role in mediating autoimmunity and inflammation. In this review, we summarize the latest knowledge on the role of miRNAs in systemic autoimmune diseases with particular focus on IIMs.

RECENT FINDINGS

Study on miRNA expression in IIMs is helping in understanding the pathogenetic basis of the disease at a tissue and systemic level. Several miRNAs, even with a muscle-specific expression (myomiRs), have been shown to be involved in immune and nonimmune mechanisms of myofiber damage. MiRNAs modulate and orchestrate the local inflammatory infiltrate and could be used as potential biomarkers as they correlate with disease activity and response to therapy.

SUMMARY

IIMs comprise different clinical phenotypes and still little is known about the molecular signature of each subset. Further research about miRNA profiling will provide additional insights in the disease characterization with an expected impact on the therapeutic strategies.

MicroRNAs Regulate Tumorigenesis by Downregulating SOCS3 Expression: An In silico Approach

Tumor microenvironment is characterized by the occurrence of significant changes due to disrupted signaling pathways that affect a broad spectrum of cellular activities such as proliferation, differentiation, signaling, invasiveness, migration, and apoptosis. Similarly, a downregulated suppressor of cytokine signaling 3 (SOCS3) promotes increased JAK/STAT function due to aberrant cytokine signaling, which results in increased cell proliferation, differentiation, and migration. Multiple carcinomas including breast cancer, prostate cancer, hepatocellular carcinoma, pancreatic cancer, and colorectal cancer involve the disruption of SOCS3 expression due to microRNA overexpression. MicroRNAs are small, conserved, and non-coding RNA molecules that regulate gene expression through post-transcriptional inhibition and mRNA destabilization. The aim of this study was to identify putative microRNAs that interact with SOCS3 and downregulate its expression. In this study, miRWalk, TargetScan, and miRDB were used to identify microRNAs that interact with SOCS3, whereas RNA22 was utilized to identify the binding sites of 238 significant microRNAs. The tertiary structures of shortlisted microRNAs and SOCS3 regions were predicted through MC Sym and RNAComposer, respectively. For molecular docking, HDOCK was used, which predicted 80 microRNA-messengerRNA complexes and the interactions of the top 5 shortlisted complexes were assessed. The complexes were shortlisted on the basis of least binding affinity score and maximum confidence score. This study identifies the interactions of known (miR-203a-5p) and novel (miR-6756-5p, miR-6732-5p, miR-1203, miR-6887-5p) microRNAs with SOCS3 regions due to their maximum interactions. Identifying the interactions of these microRNAs with SOCS3 will significantly advance the understanding of oncomiRs (miRNAs that are associated with cancer development) in tumor development due to their influence on SOCS3 expression. These insights will assist in future studies to understand the significance of miRNA-SOCS3-associated tumor development and progression.

BRG1 mediates protective ability of spermidine to ameliorate osteoarthritic cartilage by Nrf2/KEAP1 and STAT3 signaling pathway

BACKGROUND

Spermidine (SPD) is a natural polyamine that shows beneficial effects on osteoarthritis (OA). However, the effect of SPD on cartilage inflammation remains unknown. This study aimed to investigate the potential mechanisms underlying the protective effect of SPD against OA-induced articular cartilage degradation.

METHOD

SW1353 human chondrocytes were treated with hydrogen peroxide and lipopolysaccharide to induce models of inflammation and oxidative stress, followed by different dose of SPD intervention. Moreover, mice that underwent anterior cruciate ligament transection were bred and treated with SPD. The effects of SPD were observed using a CCK-8 kit, real-time polymerase chain reaction, immunoblotting, and immunofluorescent assays.

RESULT

SPD significantly increased the expression of antioxidant proteins, chondrogenic genes, and inflammatory factors both in vivo and in vitro. And injury of the mouse cartilage was also reduced by SPD. Moreover, SPD activated the Nrf2/KEAP1 pathway and inhibited STAT3 phosphorylation. BRG1 expression was decreased in osteoarthritic mouse cartilage, whereas SPD treatment caused an upregulation. However, when BRG1 was specifically inhibited by an adeno-associated virus and small interfering RNA, the antioxidant and anti-inflammatory effects of SPD were significantly diminished both in vitro and in vivo.

CONCLUSION

We found that SPD ameliorated cartilage damage in OA by activating the BRG1-mediated Nrf2/KEAP1 pathway. SPD and BRG1 may provide new therapeutic options or targets for the treatment of OA.

Mesenchymal Stromal Cells-Derived Extracellular Vesicles as Potential Treatments for Osteoarthritis

Osteoarthritis (OA) is a degenerative disease of the joints characterized by cartilage damage and severe pain. Despite various pharmacological and surgical interventions, current therapies fail to halt OA progression, leading to high morbidity and an economic burden. Thus, there is an urgent need for alternative therapeutic approaches that can effectively address the underlying pathophysiology of OA. Extracellular Vesicles (EVs) derived from mesenchymal stromal cells (MSCs) represent a new paradigm in OA treatment. MSC-EVs are small membranous particles released by MSCs during culture, both in vitro and in vivo. They possess regenerative properties and can attenuate inflammation, thereby promoting cartilage healing. Importantly, MSC-EVs have several advantages over MSCs as cell-based therapies, including lower risks of immune reactions and ethical issues. Researchers have recently explored different strategies, such as modifying EVs to enhance their delivery, targeting efficiency, and security, with promising results. This article reviews how MSC-EVs can help treat OA and how they might work. It also briefly discusses the benefits and challenges of using MSC-EVs and talks about the possibility of allogeneic and autologous MSC-EVs for medical use.

A review on the role of LINC00472 in malignant and non-malignant disorders

Long intergenic non-protein coding RNA 472 (LINC00472) has been shown to regulate diverse cellular functions and contribute to the etiology of human disorders. LINC00472 gene is located on 6q13 and has different alternatively spliced transcripts. Expression pattern and function of LINC00472 have been evaluated in different types of cancers and some other disorders, including atherosclerosis, sepsis-induced acute hepatic injury, atrial fibrillation, neuropathic pain, primary biliary cholangitis and sepsis-induced cardiac dysfunction. This lincRNA can serve as a sponge for miR-24-3p, miR-196b-5p, miR-23a-3p, miR-93-5p, miR-4311, miR-455-3p and a number of other miRNAs. LINC00472 is able to regulate several pathways, including MEK/ERK, NF-kB, PTEN/PI3K/AKT, and STAT3 signaling pathways. This raises some concerning aspects that need to be investigated further and clarified in relation to diseases. Increasing our understanding of LINC00472's crucial roles will open new doors for creating effective therapeutic approaches against cancer and related diseases. The current study aims at providing an overview of functions of LINC00472 in malignant and non-malignant disorders.

Soluble biomarkers in osteoarthritis in 2022: year in review

OBJECTIVE

To review articles reporting on the development of soluble biomarkers in osteoarthritis (OA) over the past year.

DESIGN

Two literature searches were conducted using the PubMed database for articles published between April 1, 2021 and March 31, 2022. Two searches were done, one on soluble biomarkers and another on circulating non-coding RNAs in OA. Additional articles were hand-picked to highlight emerging biomarker trends in OA.

RESULTS

Of 348 publications retrieved, we included 20 articles with 3 that were hand-picked for the narrative synthesis. We review recent data on soluble biomarkers and circulating non-coding microRNAs in OA using the BIPED classification system. We highlight studies using proteomics to show that cartilage acidic protein 1 (CRTAC1) is a promising biomarker, helping diagnose and estimate severity in hand, hip, and knee OA. Subtle changes in the structure of glycosaminoglycans from the extracellular cartilage matrix were shown to discriminate OA from non-OA cartilage. C-reactive protein metabolite (CRPM) and collagen metabolites may help discriminate subsets of OA patients as well as disease progression. Additionally, physical activity may impact determination of biomarkers. We also report on circulating microRNAs, lncRNAs, and circRNAs in OA and their predictive accuracy in diagnosis and prognosis.

CONCLUSIONS

Biomarkers for routine use are still an unmet need in the OA clinical scenario. Emerging data and novel classes of biomarkers (i.e., non-coding RNAs) show promise. Although still requiring validation in multiple independent cohorts, the past year brought advances towards a ready-to-use, reproducible, cost-effective biomarker, namely CRTAC1, to better manage the OA patient.

Breast cancer tumor microenvironment affects Treg/IL-17-producing Treg/Th17 cell axis: Molecular and therapeutic perspectives

The tumor microenvironment (TME) comprises a variety of immune cells, among which T cells exert a prominent axial role in tumor development or anti-tumor responses in patients with breast cancer (BC). High or low levels of anti-inflammatory cytokines, such as transforming growth factor β, in the absence or presence of proinflammatory cytokines, such as interleukin-6 (IL-6), delineate the fate of T cells toward either regulatory T (Treg) or T helper 17 (Th17) cells, respectively. The transitional state of RORγt⁺Foxp3⁺ Treg (IL-17-producing Treg) resides in the middle of this reciprocal polarization, which is known as Treg/IL-17-producing Treg/Th17 cell axis. TME secretome, including microRNAs, cytokines, and extracellular vesicles, can significantly affect this axis. Furthermore, immune checkpoint inhibitors may be used to reconstruct immune cells; however, some of these novel therapies may favor tumor development. Therefore, understanding secretory and cell-associated factors involved in their differentiation or polarization and functions may be targeted for BC management. This review discusses microRNAs, cytokines, and extracellular vesicles (as secretome), as well as transcription factors and immune checkpoints (as cell-associated factors), which influence the Treg/IL-17-producing Treg/Th17 cell axis in BC. Furthermore, approved or ongoing clinical trials related to the modulation of this axis in the TME of BC are described to broaden new horizons of promising therapeutic approaches.

Expression of Treg-associated lncRNAs in breast cancer

Regulatory T cells (Tregs) have important functions in tumor microenvironment, particularly for induction of immune evasion. In order to find the underlying mechanism of dysregulation of Tregs in breast cancer tissues, we designed the current study to appraise expression of five Treg-related long non-coding RNAs (lncRNAs), namely FLICR (FOXP3 Regulating Long Intergenic Non-Coding RNA), NEST (IFNG-AS1), RMRP (RNA Component of Mitochondrial RNA Processing Endoribonuclease), MAFTRR (MAF Transcriptional Regulator RNA) and TH2-LCR (Th2 Cytokine Locus Control Region) in paired breast cancer and nearby noncancerous tissues. Expression levels of RMRP, TH2-LCR, MAFTRR and GATA3-AS1 were significantly higher in breast cancer samples compared with non-tumoral tissues. The calculated AUC values for GATA3-AS1, TH2-LCR, RMRP and MAFTRR were 0.66, 0.63, 0.63 and 0.60, respectively. There were significant positive associations between expression level of RMRP gene in tumor tissues and nuclear grade, tubule formation and tumor sizes. In addition, there was a significant positive association between expression levels of MAFTRR genes in tumor tissues and nuclear grade. Besides, expression levels of FLICR were different among tumors with different levels of HER2/neu receptor. Taken together, Treg-associated lncRNAs might contribute to the pathogenesis of breast cancer.

miR‑146a‑5p protects against renal injury in MRL/lpr mice via improvement of the Treg/Th17 imbalance by targeting the TRAF6/NF‑κB axis

Dysregulated microRNA (miRNA or miR) expression is an important cause of immune homeostasis disorder in patients with systemic lupus erythematosus and lupus nephritis (LN). The present study evaluated the possibility of using miR-146a-5p as a therapeutic target for treating LN. The effects of miR-146a-5p on lupus syndrome in MRL/lpr mice were evaluated. MRL/lpr mice were injected with miR-146a-5p agomir (M146AG) or agomir negative control (NC). Renal function index, pathology and protein expression levels of inflammatory factors in MRL/lpr mice were evaluated after M146AG or agomir NC treatment. Reverse transcription-quantitative PCR, western blotting and immunofluorescence were used to assess the effect of M146AG on mRNA and protein expression levels of (tumor necrosis factor receptor-associated factor 6) TRAF6/NF-κB axis components. A luciferase dual reporter system was used to assess the mechanism of regulation of TRAF6/NF-κB axis expression. Finally, flow cytometry was used to assess the regulatory effect of M146AG on regulatory T cell (Treg)/T helper 17 (Th17) balance. The findings demonstrated that M146AG ameliorated renal lesions and the inflammatory response in MRL/lpr mice. TRAF6 was demonstrated to be targeted and significantly negatively regulated by miR-146a-5p. M146AG intervention significantly increased expression of miR-146a-5p and significantly downregulated the mRNA and protein expression levels of TRAF6 and NF-κB in CD4+ T cells of MRL/lpr mice. Furthermore, M146AG intervention alleviated Treg/Th17 imbalance in MRL/lpr mice peripheral blood. The present findings demonstrated that M146AG improved Treg/Th17 imbalance and alleviated renal lesions in MRL/lpr mice by targeting the TRAF6/NF-κB axis. This may provide a new theoretical basis for the clinical diagnosis and treatment of LN.

TRH Regulates the Synthesis and Secretion of Prolactin in Rats with Adenohypophysis through the Differential Expression of miR-126a-5p

Prolactin (PRL) is an important hormone that is secreted by the pituitary gland and plays an important role in the growth, development and reproduction of organisms. Thyrotropin-releasing hormone (TRH) is a common prolactin-releasing factor that regulates the synthesis and secretion of prolactin. In recent studies, microRNAs (miRNAs) have been found to play a key role in the regulation of pituitary hormones. However, there is a lack of systematic studies on the regulatory role that TRH plays on the pituitary transcriptome, and the role of miRNAs in the regulation of PRL synthesis and secretion by TRH lacks experimental evidence. In this study, we first investigated the changes in PRL synthesis and secretion in the rat pituitary gland after TRH administration. The results of transcriptomic analysis after TRH treatment showed that 102 genes, including those that encode Nppc, Fgf1, PRL, Cd63, Npw, and Il23a, were upregulated, and 488 genes, including those that encode Lats1, Cacna2d1, Top2a, and Tfap2a, were downregulated. These genes are all involved in the regulation of prolactin expression. The gene expression of miR-126a-5p, which regulates the level of PRL in the pituitary gland, was screened by analysis prediction software and by a dual luciferase reporter system. The data presented in this study demonstrate that TRH can regulate prolactin synthesis and secretion through miR-126a-5p, thereby improving our understanding of the molecular mechanism of TRH-mediated PRL secretion and providing a theoretical basis for the role of miRNAs in regulating the secretion of pituitary hormones.

A Systematic Review of miRNA and cfDNA as Potential Biomarkers for Liquid Biopsy in Myocarditis and Inflammatory Dilated Cardiomyopathy

Myocarditis and inflammatory dilated cardiomyopathy are cardiac diseases leading to heart failure. Liquid biopsy is a concept of replacing traditional biopsy with specialized blood tests. The study aim was to summarize and assess the usefulness of microRNAs and circulating free DNA as biomarkers of myocardial inflammation. For this systematic review, we searched Scopus, Embase, Web of Science, and PubMed. All studies measuring microRNAs in serum/plasma/cardiac tissue or circulating free DNA during myocarditis and non-ischemic dilated cardiomyopathy in humans in which healthy subjects or another cardiac disease served as a comparator were included. Data were extracted and miRNAs were screened and assessed using a scale created in-house. Then, highly graded miRNAs were assessed for usability as liquid biopsy biomarkers. Of 1185 records identified, 56 were eligible and 187 miRNAs were found. We did not identify any studies measuring circulating free DNA. In total, 24 of the screened miRNAs were included in the final assessment, 3 of which were selected as the best and 3 as potential candidates. We were not able to assess the risk of bias and the final inclusion decision was made by consensus. Serum levels of three miRNAs-miR-Chr8:96, miR-155, and miR-206-are the best candidates for myocardial inflammation liquid biopsy panel. Further studies are necessary to prove their role, specificity, and sensitivity.

Max interacting protein 1 induces IL-17-producing T helper/regulatory T imbalance in osteoarthritis by upregulating tectonic family member 2

BACKGROUND/AIM

Osteoarthritis (OA) is a common total joint disorder associated with regulatory T cell (Treg)/IL-17-producing T helper (Th17) cell imbalance. This study elucidated the mechanism underlying Th17/Treg imbalance during OA progression.

METHODS

CD4+ T cells were isolated and induced to differentiate and obtain Th17 and Treg cells, and an OA mouse model was established by anterior cruciate ligament transection surgery, followed by loss- and gain-of-function assays. Max interacting protein 1 (MXI1), tectonic family member 2 (TCTN2), Forkhead Box Protein P3 (Foxp3), signal transducer and activator of transcription 3 (STAT3), and retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt) expression was determined in cells and mice, accompanied by the measurement of the proportion of Th17 and Treg cells and the levels of interleukin (IL)- 1β, tumor necrosis factor (TNF)-α, and interferon (INF)-γ. Articular cartilage histopathology was observed by hematoxylin and eosin staining and Safranin O-Fast Green staining. Relationship between MXI1 and TCTN2 was assessed.

RESULTS

Bioinformatics analysis identified MXI1 and TCTN2 upregulation in OA patients. Mechanistically, MXI1 bound to TCTN2 promoter to promote its transcription. Upregulated MXI1 boosted INF-γ, STAT3, IL-1β, TNF-α, and RORγt levels and Th17 cell differentiation, but restricted Foxp3 expression and Treg cell differentiation in CD4+ T cells. Effects caused by overexpressed MXI1 were negated by silenced TCTN2. Also, the impacts of MXI1 overexpression on Th17/Treg imbalance and IL-1β, STAT3, TNF-α, Foxp3, INF-γ, and RORγt expression were further validated in OA mice, accompanied by aggravated articular cartilage degeneration.

CONCLUSION

Conclusively, MXI1 facilitated Th17/Treg imbalance to accelerate OA progression.

Analysis of expression of regulatory T cell related lncRNAs in inflammatory demyelinating polyneuropathies

Long non-coding RNAs that regulate function of regulatory T cells can affect pathoetiology of autoimmune disorders, such as inflammatory demyelinating polyneuropathies. In the current case-control study, we compared expression of four of these lncRNAs, namely FLICR, NEST, RMRP and TH2-LCR between patients with inflammatory demyelinating polyneuropathies and healthy subjects. Expressions of RMRP, NEST and FLICR were higher in total patients compared with controls. However, there was no significant difference in their expressions between acute and chronic demyelinating polyneuropathies. In addition, interaction of gender and disease factors had significant effect on expression levels of RMRP and TH2-LCR genes in subgroups. RMRR was superior to other lncRNAs in terms of AUC, sensitivity and specificity values in total patients and both subgroups of patients. This lncRNA could separate total patients, female patients and male patients from corresponding controls with AUC values (±SD) of 0.9 ± 0.03, 0.86 ± 0.07 and 0.93 ± 0.03, respectively. FLICR ranked second in this regard, since it could separate total patients, female patients and male patients from corresponding controls with AUC values (±SD) of 0.81 ± 0.03, 0.72 ± 0.07 and 0.87 ± 0.04, respectively. Therefore, our study provides evidence for participation of regulatory T cells-related lncRNAs in the pathoetiology of inflammatory demyelinating polyneuropathies.

Nature vs. nurture: FOXP3, genetics, and tissue environment shape Treg function

The importance of regulatory T cells (Tregs) in preventing autoimmunity has been well established; however, the precise alterations in Treg function in autoimmune individuals and how underlying genetic associations impact the development and function of Tregs is still not well understood. Polygenetic susceptibly is a key driving factor in the development of autoimmunity, and many of the pathways implicated in genetic association studies point to a potential alteration or defect in regulatory T cell function. In this review transcriptomic control of Treg development and function is highlighted with a focus on how these pathways are altered during autoimmunity. In combination, observations from autoimmune mouse models and human patients now provide insights into epigenetic control of Treg function and stability. How tissue microenvironment influences Treg function, lineage stability, and functional plasticity is also explored. In conclusion, the current efficacy and future direction of Treg-based therapies for Type 1 Diabetes and other autoimmune diseases is discussed. In total, this review examines Treg function with focuses on genetic, epigenetic, and environmental mechanisms and how Treg functions are altered within the context of autoimmunity.

LNCRNA XIST Inhibits miR-377-3p to Hinder Th17 Cell Differentiation through Upregulating ETS1

Background

Th17 cell differentiation is involved in the development and progression of many diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Present study mainly focused on the role of LINC-XIST in Th17 cell differentiation.

Methods

The naïve CD4+ T cells were isolated from human whole blood. Cells were cultured under Th17 cell-polarizing condition for 6 days. The expression of LINC-XIST and miR-153-3p was measured by qPCR. The relationship between LINC-XIST, miR-153-3p, and ETS1 was predicted by TargetScan website and authenticated by luciferase reporter assay. ELISA assays were conducted to evaluate the IL-17 concentration. Western blot was utilized to measure the protein expression of ETS1. Th17 cell frequency was examined by flow cytometry.

Results

The expression of XIST markedly decreased and miR-153-3p expression markedly increased with Th17 cell differentiation. The mRNA expression of IL-17, IL-17 concentration, and Th17 cell frequency were observably decreased in overexpressed LINC-XIST group. Luciferase reporter assay authenticated that miR-153-5p was directly regulated by LINC-XIST. miR-153-3p inhibitor observably decreased IL-17 concentration, mRNA expression of IL-17, and Th17 cell frequency while si-XIST reversed this impact. ETS1 was confirmed to be regulated by miR-153-5p via luciferase reporter assay. In addition, ETS1 markedly decreased IL-17 mRNA expression, IL-17 concentration, and Th17 cell frequency while miR-153-5p mimic reversed this impact.

Conclusion

LNCRNA XIST inhibited miR-377-3p to hinder Th17 cell differentiation through upregulating ETS1.

Leptin receptor antagonist attenuates experimental autoimmune thyroiditis in mice by regulating Treg/Th17 cell differentiation

Leptin has been found to be involved in the development and progression of many autoimmune diseases. As an organ-specific autoimmune disease, the pathogenesis of Hashimoto's thyroiditis has not been fully elucidated. It has been reported that serum leptin level is increased in Hashimoto's thyroiditis, but other studies have not shown any difference. We replicated a mouse model of experimental autoimmune thyroiditis (EAT) with a high-iodine diet and found that injection of the leptin receptor antagonist Allo-aca reduced thyroid follicle destruction and inflammatory cell infiltration in EAT mice, and thyroxine and thyroid autoimmune antibody levels. Further investigation revealed that Allo-aca promotes the differentiation of Treg cells and inhibits the differentiation of Th17 cells. We believe that Allo-aca can alter the differentiation of Treg/Th17 cells by inhibiting the leptin signaling pathway, thereby alleviating thyroid injury in EAT mice. Interfering with the leptin signaling pathway may be a novel new approach to treat treating and ameliorating Hashimoto's thyroiditis.