NF-κB-driven miR-34a impairs Treg/Th17 balance via targeting Foxp3

An Osteoimmunomodulatory Biopatch Potentiates Stem Cell Therapies for Bone Regeneration by Simultaneously Regulating IL-17/Ferroptosis Signaling Pathways

Currently, there are still great challenges in promoting bone defect healing, a common health problem affecting millions of people. Herein an osteoimmunity-regulating biopatch capable of promoting stem cell-based therapies for bone regeneration is developed. A totally biodegradable conjugate is first synthesized, which can self-assemble into bioactive nano micelles (PPT NMs). This nanotherapy effectively improves the osteogenesis of periodontal ligament stem cells (PDLSCs) under pathological conditions, by simultaneously regulating IL-17 signaling and ferroptosis pathways. Incorporation of PPT NMs into biodegradable electrospun nanofibers affords a bioactive patch, which notably improves bone formation in two rat bone defect models. A Janus bio patch is then engineered by integrating the bioactive patch with a stem cell sheet of PDLSCs. The obtained biopatch shows additionally potentiated bone regeneration capacity, by synergistically regulating osteoimmune microenvironment and facilitating stem cell differentiation. Further surface functionalization of the biopatch with tannic acid considerably increases its adhesion to the bone defect, prolongs local retention, and sustains bioactivities, thereby offering much better repair effects in rats with mandibular or cranial bone defects. Moreover, the engineered bioactive patches display good safety. Besides bone defects, this osteoimmunity-regulating biopatch strategy can be applied to promote stem cell therapies for spinal cord injury, wound healing, and skin burns.

NF-κB factors cooperate with Su(Hw)/E4F1 to balance Drosophila/human immune responses via modulating dynamic expression of miR-210

MicroRNAs (miRNAs) play crucial regulatory roles in controlling immune responses, but their dynamic expression mechanisms are poorly understood. Here, we firstly confirm that the conserved miRNA miR-210 negatively regulates innate immune responses of Drosophila and human via targeting Toll and TLR6, respectively. Secondly, our findings demonstrate that the expression of miR-210 is dynamically regulated by NF-κB factor Dorsal in immune response of Drosophila Toll pathway. Thirdly, we find that Dorsal-mediated transcriptional inhibition of miR-210 is dependent on the transcriptional repressor Su(Hw). Mechanistically, Dorsal interacts with Su(Hw) to modulate cooperatively the dynamic expression of miR-210 in a time- and dose-dependent manner, thereby controlling the strength of Drosophila Toll immune response and maintaining immune homeostasis. Fourthly, we reveal a similar mechanism in human cells, where NF-κB/RelA cooperates with E4F1 to regulate the dynamic expression of hsa-miR-210 in the TLR immune response. Overall, our study reveals a conservative regulatory mechanism that maintains animal innate immune homeostasis and provides new insights into the dynamic regulation of miRNA expression in immune response.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Inhibition of Foxp3 expression in the placenta of mice infected intraperitoneally by toxoplasma gondii tachyzoites: insights into the PPARγ/miR-7b-5p/Sp1 signaling pathway

BACKGROUND

Toxoplasma gondii, an obligate intracellular parasitic protozoa, infects approximately 30% of the global population. Contracting T. gondii at the primary infection of the mother can result in neonatal microcephaly, chorioretinitis, hydrocephalus, or mortality. Our previous study indicated that pregnant mice infected with T. gondii displayed a decrease in both the number and the suppressive ability of regulatory T cells, accompanied by the reduced Forkhead box P3 (Foxp3). Numerous studies have proved that microRNAs (miRNAs) are implicated in T. gondii infection, but there is meager evidence on the relationship between alterations of miRNAs and downregulation of Foxp3 induced by T. gondii.

METHODS

Quantitative reverse transcription polymerase chain reaction was utilized to detect the transcriptions of miRNAs and Foxp3. Protein blotting and immunofluorescence were used to detect the expressions of Foxp3 and related transcription factors. The structure of mouse placenta was observed by hematoxylin and eosin (HE) staining. To examine the activity of miR-7b promoter and whether miR-7b-5p targets Sp1 to suppress Foxp3 expression, we constructed recombinant plasmids containing the full-length/truncated/mutant miR-7b promoter sequence or wildtype/mutant of Sp1 3' untranslated region (3' UTR) to detect the fluorescence activity in EL4 cells.

RESULTS

In T. gondii-infected mice, miR-7b transcription was significantly elevated, while Foxp3 expression was decreased in the placenta. In vitro, miR-7b mimics downregulated Foxp3 expression, whereas its inhibitors significantly upregulated Foxp3 expression. miR-7b promoter activity was elevated upon the stimulation of T. gondii antigens, which was mitigated by co-transfection of mutant miR-7b promoter lacking peroxisome proliferator-activated receptor γ (PPARγ) target sites. Additionally, miR-7b mimics diminished Sp1 expression, while miR-7b inhibitors elevated its expression. miR-7b mimics deceased the fluorescence activity of Sp1 3' untranslated region (3' UTR), but it failed to impact the fluorescence activity upon the co-transfection of mutant Sp1 3' UTR lacking miR-7b target site.

CONCLUSIONS

T. gondii infection and antigens promote miR-7b transcription but inhibit Foxp3 protein and gene levels. T. gondii antigens promote miR-7b promoter activity by a PPARγ-dependent mechanism. miR-7b directly binds to Sp1 3' UTR to repress Sp1 expression. Understanding the regulatory functions by which T. gondii-induced miR-7b suppresses Foxp3 expression can provide new perspectives for the possible therapeutic avenue of T. gondii-induced adverse pregnancy outcomes.

Microarray analysis of microrna expression in peripheral blood mononuclear cells of patients with polymyositis and dermatomyositis

Background and Objectives

MicroRNAs (miRNAs) represent a new class of biomarkers in the context of connective tissue disorders. The miRNA expression profiles in peripheral blood mononuclear cells (PBMCs) of patients with polymyositis (PM) and dermatomyositis (DM) have not been fully elucidated. The objective is to investigate miRNAs expression profile in PBMCs of patients with PM/DM.

Methods

Microarray technology was used to identify differentially expressed miRNAs in PBMCs obtained from 6 untreated PM/DM patients and 3 healthy controls (HCs). TaqMan-based stem-loop real-time PCR detection was used for validation in a cohort of 34 PM/DM patients and 20 HCs.

Results

Microarray analysis revealed 38 differentially expressed miRNAs (24 up-regulated and 14 down-regulated) in PM/DM patients compared to HCs. Four miRNAs (miR-320a, miR-335-3p, miR-34a-5p and miR-454-3p) were chosen for real-time PCR validation. The expression of miR-34a-5p was significantly upregulated in PM/DM group (P < 0.05). In subgroup analysis, miR-34a-5p was significantly upregulated in interstitial lung disease (ILD) group and DM group (P < 0.001). The level of SIRT1, a validated target of miR-34a, was significantly lower in PBMCs of PM/DM patients compared with HCs.

Conclusions

MiR-34a-5p may potentially participate in the pathogenesis of PM/DM through SIRT1, and may serve as a potential new biomarker for PM/DM-ILD.

NF-κB in biology and targeted therapy: new insights and translational implications

NF-κB signaling has been discovered for nearly 40 years. Initially, NF-κB signaling was identified as a pivotal pathway in mediating inflammatory responses. However, with extensive and in-depth investigations, researchers have discovered that its role can be expanded to a variety of signaling mechanisms, biological processes, human diseases, and treatment options. In this review, we first scrutinize the research process of NF-κB signaling, and summarize the composition, activation, and regulatory mechanism of NF-κB signaling. We investigate the interaction of NF-κB signaling with other important pathways, including PI3K/AKT, MAPK, JAK-STAT, TGF-β, Wnt, Notch, Hedgehog, and TLR signaling. The physiological and pathological states of NF-κB signaling, as well as its intricate involvement in inflammation, immune regulation, and tumor microenvironment, are also explicated. Additionally, we illustrate how NF-κB signaling is involved in a variety of human diseases, including cancers, inflammatory and autoimmune diseases, cardiovascular diseases, metabolic diseases, neurological diseases, and COVID-19. Further, we discuss the therapeutic approaches targeting NF-κB signaling, including IKK inhibitors, monoclonal antibodies, proteasome inhibitors, nuclear translocation inhibitors, DNA binding inhibitors, TKIs, non-coding RNAs, immunotherapy, and CAR-T. Finally, we provide an outlook for research in the field of NF-κB signaling. We hope to present a stereoscopic, comprehensive NF-κB signaling that will inform future research and clinical practice.

MicroRNA-125b mediates Interferon-γ-induced downregulation of the vitamin D receptor in systemic lupus erythematosus

BACKGROUND

The inflammatory factor interferon (IFN)-γ is related to the occurrence and development of systemic lupus erythematosus (SLE). The vitamin D receptor (VDR) has an anti-inflammatory effect and its downregulation is involved in the onset of SLE. Our previous studies have confirmed that the expression of VDR in SLE peripheral blood mononuclear cells (PBMCs) is downregulated, which is negatively correlated with disease activity and inflammation. However, the mechanism underlying VDR downregulation in SLE is unknown.

METHODS

Based on the results of computer simulation analysis, the expression of VDR and four microRNAs (miR-17-3p, miR-34a, miR-346, and miR-125b) in SLE PBMC cells was analyzed under proinflammatory cytokine IFN‑γ treatment, and miR-125b was identified as the target miRNA. The relationship between IFN‑γ, miR-125b, and VDR was further assessed in THP‑1 cells.

RESULTS

We showed that IFN‑γ inhibited the expression of VDR and miR-125b. Further study revealed that VDR mRNA was positively correlated with miR-125b in THP‑1 cells after IFN‑γ intervention. After transfection of miR-125b mimic or inhibitor, the expression of VDR in the miR-125b inhibitor group was lower than in the control group and miR-125b mimic group, while expression in the control group was lower than in miR-125b mimic group. Transfection of miR-125b inhibitor into THP‑1 cells could further promote the ability of IFN‑γ to inhibit VDR.

CONCLUSION

The decrease in VDR expression promotes development of inflammation and SLE. These data suggest that miR-125b may mediate inflammatory factor IFN-γ-induced downregulation of VDR in the pathogenesis of SLE.

Impact of inflammation and Treg cell regulation on neuropathic pain in spinal cord injury: mechanisms and therapeutic prospects

Spinal cord injury is a severe neurological trauma that can frequently lead to neuropathic pain. During the initial stages following spinal cord injury, inflammation plays a critical role; however, excessive inflammation can exacerbate pain. Regulatory T cells (Treg cells) have a crucial function in regulating inflammation and alleviating neuropathic pain. Treg cells release suppressor cytokines and modulate the function of other immune cells to suppress the inflammatory response. Simultaneously, inflammation impedes Treg cell activity, further intensifying neuropathic pain. Therefore, suppressing the inflammatory response while enhancing Treg cell regulatory function may provide novel therapeutic avenues for treating neuropathic pain resulting from spinal cord injury. This review comprehensively describes the mechanisms underlying the inflammatory response and Treg cell regulation subsequent to spinal cord injury, with a specific focus on exploring the potential mechanisms through which Treg cells regulate neuropathic pain following spinal cord injury. The insights gained from this review aim to provide new concepts and a rationale for the therapeutic prospects and direction of cell therapy in spinal cord injury-related conditions.

MicroRNAs are dysregulated in peripheral blood mononuclear cells in multiple sclerosis and correlate with T cell mediators

T cell mediators and microRNAs are involved in the pathogenesis of multiple sclerosis (MS), but their interaction largely remains undetermined. We investigated by RT-qPCR the dysregulation of microRNAs in peripheral blood mononuclear cells of MS patients versus healthy controls, according to radiological disease activity or treatment. Several microRNAs correlated positively/negatively with IL21/FOXP3 mRNA expression, but not with serum neurofilament light chain levels. Cytokine expression is conceivably balanced by several regulators, whereas microRNAs possibly target upstream transcription factors rather than directly cytokine mRNAs. Functional studies are needed to investigate their interaction, notably for the predicted targeting of FOXP3 by miR-34c-5p.

Epigenetic Dysregulation in the Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease in which immune disorders lead to autoreactive immune responses and cause inflammation and tissue damage. Genetic and environmental factors have been shown to trigger SLE. Recent evidence has also demonstrated that epigenetic factors contribute to the pathogenesis of SLE. Epigenetic mechanisms play an important role in modulating the chromatin structure and regulating gene transcription. Dysregulated epigenetic changes can alter gene expression and impair cellular functions in immune cells, resulting in autoreactive immune responses. Therefore, elucidating the dysregulated epigenetic mechanisms in the immune system is crucial for understanding the pathogenesis of SLE. In this paper, we review the important roles of epigenetic disorders in the pathogenesis of SLE.

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.

Treg plasticity and human diseases

INTRODUCTION

As a subset of CD4+ T cells, regulatory T cells (Tregs) with the characteristic expression of transcription factor FOXP3 play a key role in maintaining self-tolerance and regulating immune responses. However, in some inflammatory circumstances, Tregs can express cytokines of other T help (Th) cells by internal reprogramming, which is called Treg plasticity. These reprogrammed Tregs with impaired suppressive ability contribute to the progression of diseases by secreting pro-inflammatory cytokines. However, in the tumor microenvironment (TME), such changes in phenotype rarely occur in Tregs, on the contrary, Tregs usually display a stronger suppressive function and inhibit anti-tumor immunity. It is important to understand the mechanisms of Treg plasticity in inflammatory diseases and cancers.

OBJECTIVES

In this review, we summarize the characteristics of different Th-like Tregs and discuss the potential mechanisms of these changes in phenotype. Furthermore, we summarize the Treg plasticity in human diseases and discuss the effects of these changes in phenotype on disease progression, as well as the potential application of drugs or reagents that regulate Treg plasticity in human diseases.

CONCLUSIONS

Treg plasticity is associated with inflammatory diseases and cancers. Regulating Treg plasticity is a promising direction for the treatment of inflammatory diseases and cancers.

The role of retinoic acid receptor-related orphan receptors in skeletal diseases

Bone homeostasis, depending on the balance between bone formation and bone resorption, is responsible for maintaining the proper structure and function of the skeletal system. As an important group of transcription factors, retinoic acid receptor-related orphan receptors (RORs) have been reported to play important roles in bone homeostasis by regulating the transcription of target genes in skeletal cells. On the other hand, the dysregulation of RORs often leads to various skeletal diseases such as osteoporosis, rheumatoid arthritis (RA), and osteoarthritis (OA). Herein, we summarized the roles and mechanisms of RORs in skeletal diseases, aiming to provide evidence for potential therapeutic strategies.

Non-coding RNA in tumor-infiltrating regulatory T cells formation and associated immunotherapy

Cancer immunotherapy has exhibited promising antitumor effects in various tumors. Infiltrated regulatory T cells (Tregs) in the tumor microenvironment (TME) restrict protective immune surveillance, impede effective antitumor immune responses, and contribute to the formation of an immunosuppressive microenvironment. Selective depletion or functional attenuation of tumor-infiltrating Tregs, while eliciting effective T-cell responses, represents a potential approach for anti-tumor immunity. Furthermore, it does not disrupt the Treg-dependent immune homeostasis in healthy organs and does not induce autoimmunity. Yet, the shared cell surface molecules and signaling pathways between Tregs and multiple immune cell types pose challenges in this process. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), regulate both cancer and immune cells and thus can potentially improve antitumor responses. Here, we review recent advances in research of tumor-infiltrating Tregs, with a focus on the functional roles of immune checkpoint and inhibitory Tregs receptors and the regulatory mechanisms of ncRNAs in Treg plasticity and functionality.

Paris polyphylla extract attenuates colitis in mice by regulating PPAR-γ mediated Treg/Th17 balance

ETHNOPHARMACOLOGICAL RELEVANCE

Paris polyphylla Sm. (P.P), is a widely-used traditional Chinese medicine (TCM) in the treatment of wound, throat sores and snakebites. Furthermore, P.P was recorded as an anti-inflammatory drug by the Chinese Pharmacopoeia.

AIM OF THE STUDY

We sought to decipher the anti-inflammatory effect of P.P on ulcerative colitis (UC); specifically, to explore whether P.P attenuates colitis by restoring the regulatory T cells (Tregs) and T helper 17 (Th17) cells balance and its mechanism.

MATERIAL AND METHODS

We treated experimental colitis mice with extracts of Paris polyphylla (EPP). The percentage of Tregs and Th17 cells were measured using flow cytometry, and their secreted cytokines levels were evaluated employing ELISA. The expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) in colon tissues was detected using immunofluorescence. Furthermore, GW9662, a PPAR-γ antagonist, was used to validate the mechanism of EPP in restoring the Treg/Th17 balance.

RESULTS

The EPP effectively alleviated the clinical symptoms and inflammatory cytokine levels in mice with colitis. EPP treatment also restored the impaired Treg/Th17 balance in mice. Furthermore, EPP treatment promoted PPAR-γ expression and reduced HIF-1α and p-STAT3 expression in colon tissues, whereas PPAR-γ inhibition blocked the effects of EPP in mice models.

CONCLUSION

Our study indicates that EPP exhibit excellent anti-inflammatory properties via restoring PPAR-γ/STAT3/HIF-1α axis-mediated Treg/Th17 balance in colitis mice. Hence, P. polyphylla is a promising medicinal plant-based alternative for managing colitis that requires further clinical validation.

Obesity, but not high-fat diet, is associated with bone loss that is reversed via CD4+CD25+Foxp3+ Tregs-mediated gut microbiome of non-obese mice

Osteoporosis is characterized by decreased bone mass, microarchitectural deterioration, and increased bone fragility. High-fat diet (HFD)-induced obesity also results in bone loss, which is associated with an imbalanced gut microbiome. However, whether HFD-induced obesity or HFD itself promotes osteoclastogenesis and consequent bone loss remains unclear. In this study, we developed HFD-induced obesity (HIO) and non-obesity (NO) mouse models to evaluate the effect of HFD on bone loss. NO mice were defined as body weight within 5% of higher or lower than that of chow diet fed mice after 10 weeks HFD feeding. NO was protected from HIO-induced bone loss by the RANKL /OPG system, with associated increases in the tibia tenacity, cortical bone mean density, bone volume of cancellous bone, and trabecular number. This led to increased bone strength and improved bone microstructure via the microbiome-short-chain fatty acids (SCFAs) regulation. Additionally, endogenous gut-SCFAs produced by the NO mice activated free fatty acid receptor 2 and inhibited histone deacetylases, resulting in the promotion of Treg cell proliferation in the HFD-fed NO mice; thereby, inhibiting osteoclastogenesis, which can be transplanted by fecal microbiome. Furthermore, T cells from NO mice retain differentiation of osteoclast precursors of RAW 264.7 macrophages ex vivo. Our data reveal that HFD is not a deleterious diet; however, the induction of obesity serves as a key trigger of bone loss that can be blocked by a NO mouse-specific gut microbiome.

MicroRNA-143-3p ameliorates collagen-induced arthritis by polarizing naive CD4+ T cells into Treg cells

BACKGROUND

Rheumatoid arthritis (RA) is a persistent and systemic autoimmunity disease. The abnormal differentiation of Treg cells is important in pathogenesis. Despite previous studies showed that microRNAs (miRNAs, miR) are pivotal modulators of Treg cells, the effect of miRNAs on Treg cell differentiation and function is not clear. Our study wants to reveal the relationship of miR-143-3p with the differentiative ability and biofunction of Treg cells during the development of RA.

METHODS

The Expressing level of miR-143-3p and cell factor generation in peripheral blood (PB) of RA sufferers were identified by ELISA or RT-qPCR. The roles of miR-143-3p in Treg cell differentiation were studied via ShRNA/lentivirus transfection. Male DBA/1 J mice were separated into control, model, control mimics, and miR-143-3p mimics groups to analyze the anti-arthritis efficacy, the differentiative ability of Treg cells, and the expression level of miR-143-3p.

RESULTS

Our team discovered that the Expressing level of miR-143-3p was related to RA disease activities in a negative manner, and remarkably related to antiinflammation cell factor IL-10. In vitro, the expression of miR-143-3p in the CD4⁺ T cells upregulated the percentage of CD4⁺ CD25⁺ Fxop3⁺ cells (Tregs) and forkhead box protein 3 (Foxp3) mRNA expression. Evidently, miR-143-3p mimic intervention considerably upregulated the content of Treg cells in vivo, validly avoided CIA progression, and remarkably suppressed the inflammatory events of joints in mice.

CONCLUSION

Our findings indicated that miR-143-3p could ameliorate CIA through polarizing naive CD4⁺ T cells into Treg cells, which may be a novel strategy to treat autoimmune diseases such as RA.

Identification of a novel role for the immunomodulator ILRUN in the development of several T cell subsets in mice

Inflammation and lipid regulator with UBA-like and NBR1-like domains (ILRUN) is a protein-encoding gene associated with innate immune signaling, lipid metabolism and cancer. In the context of innate immunity, ILRUN inhibits IRF3-mediated transcription of antimicrobial and proinflammatory cytokines by inducing degradation of the transcriptional coactivators CBP and p300. There remains a paucity of information, however, regarding the innate immune roles of ILRUN beyond in vitro analyses. To address this, we utilize a knockout mouse model to investigate the effect of ILRUN on cytokine expression in splenocytes and on the development of immune cell populations in the spleen and thymus. We show elevated production of tumor necrosis factor and interleukin-6 cytokines in ILRUN-deficient splenocytes following stimulation with the innate immune ligands polyinosinic:polycytidylic acid or lipopolysaccharide. Differences were also observed in the populations of several T cell subsets, including regulatory, mucosal-associated invariant and natural killer. These data identify novel functions for ILRUN in the development of certain immune cell populations and support previous in vitro findings that ILRUN negatively regulates the synthesis of pathogen-stimulated cytokines. This establishes the ILRUN knockout mouse model as a valuable resource for further study of the functions of ILRUN in health and disease.

Gancao Fuzi decoction regulates the Th17/Treg cell imbalance in rheumatoid arthritis by targeting Foxp3 via miR-34a

ETHNOPHARMACOLOGICAL RELEVANCE

During the Eastern Han Dynasty, Zhang Zhongjing first recorded the Gancao Fuzi decoction (GCFZD) formula in the "Synopsis of the Golden Chamber", which is reportedly an effective and safe treatment for rheumatoid arthritis (RA). However, the mechanism underlying the observed improvement in the T helper 17 (Th17)/regulatory T (Treg) cell imbalance in RA obtained with GCFZD has not been reported.

AIM OF THE STUDY

This study aimed to demonstrate whether GCFZD ameliorated RA by modulating the Th17/Treg imbalance in RA mice.

MATERIALS AND METHODS

Collagen was used to induce a model of collagen-induced arthritis (CIA) in mice. GCFZD was administered by gavage, and the arthritis index score, imaging and histopathological changes of the ankle joints, and the levels of the immunoglobulin G (IgG) class antibodies and proinflammatory factors in serum were determined. In addition, the frequencies of Th17 and Treg cells, the levels of relevant transcription factors and functional factors and the miR-34a gene in the spleen and the levels of interleukin-17A (IL-17A) and IL-10 in serum were determined.

RESULTS

GCFZD significantly reduced the arthritis score, improved joint swelling and bone damage, reduced the pathological score, and decreased the serum levels of IgG class antibody (IgG and IgG2a) and proinflammatory factor [tumour necrosis factor-alpha (TNF-α), IL-1β and IL-6]. Moreover, the Th17-cell proportion, the expression level of the Th17-specific transcription factor retinoic acid-related orphan receptor γt (RORγt) and functional factor IL-17A in the spleen, and the serum IL-17A level were decreased, whereas the Treg cell proportion, expression levels of the Treg-specific transcription factor forkhead box P3 (Foxp3) and functional factor IL-10 in the spleen, and the serum IL-10 level were increased. Furthermore, GCFZD inhibited miR-34a gene expression while promoting Foxp3 protein expression.

CONCLUSIONS

The findings of this study demonstrate the therapeutic effect of GCFZD on mice with CIA, and the mechanism is related to an improvement in the Th17/Treg cell imbalance by targeting Foxp3 via miR-34a.

Comprehensive overview of microRNA function in rheumatoid arthritis

MicroRNAs (miRNAs), a class of endogenous single-stranded short noncoding RNAs, have emerged as vital epigenetic regulators of both pathological and physiological processes in animals. They direct fundamental cellular pathways and processes by fine-tuning the expression of multiple genes at the posttranscriptional level. Growing evidence suggests that miRNAs are implicated in the onset and development of rheumatoid arthritis (RA). RA is a chronic inflammatory disease that mainly affects synovial joints. This common autoimmune disorder is characterized by a complex and multifaceted pathogenesis, and its morbidity, disability and mortality rates remain consistently high. More in-depth insights into the underlying mechanisms of RA are required to address unmet clinical needs and optimize treatment. Herein, we comprehensively review the deregulated miRNAs and impaired cellular functions in RA to shed light on several aspects of RA pathogenesis, with a focus on excessive inflammation, synovial hyperplasia and progressive joint damage. This review also provides promising targets for innovative therapies of RA. In addition, we discuss the regulatory roles and clinical potential of extracellular miRNAs in RA, highlighting their prospective applications as diagnostic and predictive biomarkers.

Epigenetic Regulations in Autoimmunity and Cancer: from Basic Science to Translational Medicine

Epigenetics, as a discipline that aims to explain the differential expression of phenotypes arising from the same gene sequence and the heritability of epigenetic expression, has received much attention in medicine. Epigenetic mechanisms are constantly being discovered, including DNA methylation, histone modifications, noncoding RNAs and m6A. The immune system mainly achieves an immune response through the differentiation and functional expression of immune cells, in which epigenetic modification will have an important impact. Because of immune infiltration in the tumor microenvironment, immunotherapy has become a research hotspot in tumor therapy. Epigenetics plays an important role in autoimmune diseases and cancers through immunology. An increasing number of drugs targeting epigenetic mechanisms, such as DNA methyltransferase inhibitors, histone deacetylase inhibitors, and drug combinations, are being evaluated in clinical trials for the treatment of various cancers (including leukemia and osteosarcoma) and autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis). This review summarizes the progress of epigenetic regulation for cancers and autoimmune diseases to date, shedding light on potential therapeutic strategies.

The effect of combining PD-1 agonist and low-dose Interleukin-2 on treating systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease involving multiple organs. It is often called "immortal cancer" due to the difficulties in disease treatment. As the cornerstone of immune regulation, the programmed cell death protein 1 (PD-1) has been extensively studied in the context of chronic inflammation due to its ability of regulating immune response and immunosuppression. Recently, more and more studies on rheumatic immune related complications have also focused on PD-1 and proposed that the use of PD-1 agonist could inhibit the activation of lymphocytes and alleviate SLE disease activity. In this review, we summarized the role of PD-1 in SLE, implicating its potential application as a biomarker to predict SLE disease activity; we also proposed that the combination of PD-1 agonist and low-dose IL-2 may have better therapeutic efficacy, shining light on a new direction for developing specific treatment approaches.

An update on epigenetic regulation in autoimmune diseases

Autoimmune diseases (AIDs) generally manifest as chronic immune disorders characterized by significant heterogeneity and complex symptoms. The discordant incidence of AIDs between monozygotic twins guided people to attach importance to environmental factors. Epigenetics is one of the major ways to be influenced, some of them can even occur years before clinical diagnosis. With the advent of high-throughput omics times, the mysterious veil of epigenetic modification in AIDs has been gradually unraveled, and some progress has been made in utilizing it as indicators of diagnosis and disease activity. For example, the hypomethylated IFI44L promoter in diagnosing systematic lupus erythematosus (SLE). More recently, newly identified noncoding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), are also believed to be involved in the etiology of AIDs while the initial factor behind those epigenetic alterations can be diverse from metabolism to microbiota. Update and comprehensive insights into epigenetics in AIDs can help us understand the pathogenesis and further orchestrate it to benefit patients in the future. Therefore, we reviewed the latest epigenetic findings in SLE, rheumatoid arthritis (RA), Type 1 diabetes (T1D), systemic sclerosis (SSc) primarily from cellular levels.

Modulation of immunosuppressive cells and noncoding RNAs as immunotherapy in osteosarcoma

The most common bone cancer is osteosarcoma (OS), which mostly affects children and teenagers. Early surgical resection combined with chemotherapy significantly improves the prognosis of patients with OS. Existing chemotherapies have poor efficacy in individuals with distant metastases or inoperable resection, and these patients may respond better to novel immunotherapies. Immune escape, which is mediated by immunosuppressive cells in the tumour microenvironment (TME), is a major cause of poor OS prognosis and a primary target of immunotherapy. Myeloid-derived suppressor cells, regulatory T cells, and tumour-associated macrophages are the main immunosuppressor cells, which can regulate tumorigenesis and growth on a variety of levels through the interaction in the TME. The proliferation, migration, invasion, and epithelial-mesenchymal transition of OS cells can all be impacted by the expression of non-coding RNAs (ncRNAs), which can also influence how immunosuppressive cells work and support immune suppression in TME. Interferon, checkpoint inhibitors, cancer vaccines, and engineered chimeric antigen receptor (CAR-T) T cells for OS have all been developed using information from studies on the metabolic properties of immunosuppressive cells in TME and ncRNAs in OS cells. This review summarizes the regulatory effect of ncRNAs on OS cells as well as the metabolic heterogeneity of immunosuppressive cells in the context of OS immunotherapies.

MiR-125b-5p modulates the function of regulatory T cells in tumor microenvironment by targeting TNFR2

BACKGROUND

Tumor necrosis factor receptor type 2 (TNFR2) is primarily expressed by CD4⁺FoxP3⁺ regulatory T cells (Tregs), especially those present in tumor microenvironment. There is compelling evidence that TNFR2 plays a crucial role in the activation, expansion, and phenotypic stability of Tregs and promotes tumor immune evasion. Understanding of epigenetic regulation of TNFR2 expression in Tregs may help device a novel strategy in cancer immunotherapy.

METHODS

MiR-125b-5p-overexpressing or knockdown murine CD4 T cells and Tregs were constructed, and the effect of miR-125b-5p on Tregs proliferation, suppressive function and TNFR2 expression were examined. In vivo antitumor efficacy of Ago-125b-5p (miR-125b-5p agomir) was evaluated in MC38 tumor bearing mice, and tumor-infiltrating Tregs and CD8⁺ cytotoxic T lymphocytes (CTLs) were analyzed. RNA-seq analysis was applied to reveal the genes and signaling pathways regulated by miR-125b-5p in Tregs.

RESULTS

In this study, we found that TNFR2 was a direct target of miR-125b-5p. Overexpression of miR-125b-5p decreased the proportion of Tregs and their expression of TNFR2 and consequently inhibited its proliferation and suppressive function by regulating the metabolism-related signaling pathways. Moreover, in colon cancer bearing mice, the administration of Ago-125b-5p markedly inhibited the tumor growth, which was associated with reduction of Tregs and increase of IFNγ⁺CD8⁺ T cells in tumor environment. Furthermore, in human colon adenocarcinoma patients, we verified that miR-125b-5p expression was downregulated, and low levels of miR-125b-5p were associated with poor prognosis. Interestingly, the expression of miR-125b-5p and TNFR2 were negatively correlated.

CONCLUSIONS

Our study for the first time found that the expression of TNFR2 by Tregs was regulated by miR-125b-5p. Our results showed that miR-125b-5p had the capacity to inhibit the expression of TNFR2 and immunosuppressive activity of Tregs and consequently enhanced the antitumor efficacy. This property of miR-125b-5p may be therapeutically harnessed in the treatment of human cancers.

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.

Mechanism Involved in Acute Liver Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (I/R) is a common pathophysiological process, which can occur in many conditions such as acute enteric ischemia, severe burns, small intestinal transplantation, etc,. Ischemia-reperfusion of the intestine is often accompanied by distal organ injury, especially liver injury. This paper outlined the signal pathways and cytokines involved in acute liver injury induced by intestinal I/R: the NF-κB Signaling Pathway, the P66shc Signaling Pathway, the HMGB1 Signaling Pathway, the Nrf2-ARE Signaling Pathway, the AMPK-SIRT-1 Signaling Pathway and other cytokines, providing new ideas for the prevention and treatment of liver injury caused by reperfusion after intestinal I/R.

Astragalus Polysaccharide Relieves Inflammatory Responses in Guinea Pigs with Allergic Rhinitis via Ameliorating NF-kB-Mediated Treg/Th17 Imbalance

BACKGROUND

Allergic rhinitis (AR) is regarded as a prevalent and non-infectious inflammation in nasal mucosa, and astragalus polysaccharide (APS) could mitigate inflammation.

OBJECTIVES

Herein, this study probed the specific mechanism of APS in inflammatory responses in AR.

METHODS

Firstly, AR guinea pig models were established through the stimulation and sensitization of ovalbumin (OVA) and received APS treatment. Changes in nasal symptoms were assessed through counting the sneezing and rubbing times of guinea pigs. The change patterns of OVA-specific immunoglobulin-E (OVA-sIgE), OVA-specific immunoglobulin-G1 (OVA-sIgG1), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in guinea pig serum were identified. Meanwhile, the levels of IL-17, transforming growth factor (TGF)-β, IL-10, and forkhead box protein P3 (Foxp3) in the guinea pig tissues or serum were examined, and CD25⁺Foxp3⁺Treg or CD4⁺IL17⁺Th17 cell proportion was detected. Afterwards, nuclear factor-kappa B (NF-kB) expression in guinea pig nasal mucosa tissues were examined. Rescue experiments were designed to probe the role of NF-kB overexpression in inflammatory responses and Treg/Th17 imbalance in AR guinea pigs.

RESULTS

APS treatment reduced sneezing and rubbing times of AR guinea pigs and suppressed OVA-sIgE, OVA-sIgG1, TNF-α, and IL-6 levels in guinea pig serum, and meanwhile, increased CD25⁺Foxp3⁺Treg cell proportion while reduced CD4⁺IL17⁺Th17 cell proportion in AR guinea pig serum or tissues, in a dose-dependent manner. NF-kB was highly-expressed in AR guinea pigs and down-regulated after APS treatment. NF-kB overexpression facilitated inflammatory responses and Treg/Th17 imbalance in AR.

CONCLUSION

APS reduced Treg/Th17 imbalance via suppressing NF-kB expression, thereby ameliorating inflammatory responses in AR.

Hair Follicle-Related MicroRNA-34a Serum Expression and rs2666433A/G Variant in Patients with Alopecia: A Cross-Sectional Analysis

Alopecia areata (AA) is a type of immune-mediated alopecia. Recent studies have suggested microRNAs’ (miRNAs) implication in several cellular processes, including epidermal and hair follicle biology. Single nucleotide polymorphisms (SNPs) can modify gene expression levels, which may induce an autoimmune response. This case−control study included 480 participants (240 for each case/control group). MicroRNA-34a gene (MIR-34A) rs2666433A/G variant was genotyped using real-time allelic discrimination polymerase chain reaction (PCR). Additionally, circulatory miR-34a levels were quantified by quantitative reverse transcription PCR (qRT-PCR). On comparing between alopecia and non-alopecia cohorts, a higher frequency of A variant was noted among patients when compared to controls—A allele: 28 versus 18% (p < 0.001); A/A genotype: 9 versus 2%; A/G genotype: 39 versus 32% (p < 0.001). A/A and A/G carriers were more likely to develop alopecia under heterozygote comparison (OR = 1.83, 95% CI = 1.14−2.93), homozygote comparison (OR = 4.19, 95% CI = 1.33−13.1), dominant (OR = 2.0, 95% CI = 1.27−3.15), recessive (OR = 3.36, 95% CI = 1.08−10.48), over-dominant (OR = 1.65, 95% CI = 1.04−32.63), and log additive (OR = 1.91, 95% CI = 1.3−2.82) models. Serum miR-34a expression levels were upregulated in alopecia patients with a median and quartile fold change of 27.3 (1.42−2430). Significantly higher levels were more pronounced in A/A genotype patients (p < 0.01). Patients carrying the heterozygote genotype (rs2666433 * A/G) were two times more likely to develop more severe disease grades. Stratified analysis by sex revealed the same results. A high expression level was associated with concomitant autoimmune comorbidities (p = 0.001), in particular SLE (p = 0.007) and vitiligo (p = 0.049). In conclusion, the MIR34A rs2666433 (A/G) variant is associated with AA risk and severity in the studied population. Furthermore, high miR-34a circulatory levels could play a role in disease pathogenesis.

Kidney microRNA Expression Pattern in Type 2 Diabetic Nephropathy in BTBR Ob/Ob Mice

Diabetic nephropathy (DN) is the main leading cause of chronic kidney disease worldwide. Although remarkable therapeutic advances have been made during the last few years, there still exists a high residual risk of disease progression to end-stage renal failure. To further understand the pathogenesis of tissue injury in this disease, by means of the Next-Generation Sequencing, we have studied the microRNA (miRNA) differential expression pattern in kidneys of Black and Tan Brachyury (BTBR) ob/ob (leptin deficiency mutation) mouse. This experimental model of type 2 diabetes and obesity recapitulates the key histopathological features described in advanced human DN and therefore can provide potential useful translational information. The miRNA-seq analysis, performed in the renal cortex of 22-week-old BTBR ob/ob mice, pointed out a set of 99 miRNAs significantly increased compared to non-diabetic, non-obese control mice of the same age, whereas no miRNAs were significantly decreased. Among them, miR-802, miR-34a, miR-132, miR-101a, and mir-379 were the most upregulated ones in diabetic kidneys. The in silico prediction of potential targets for the 99 miRNAs highlighted inflammatory and immune processes, as the most relevant pathways, emphasizing the importance of inflammation in the pathogenesis of kidney damage associated to diabetes. Other identified top canonical pathways were adipogenesis (related with ectopic fatty accumulation), necroptosis (an inflammatory and regulated form of cell death), and epithelial-to-mesenchymal transition, the latter supporting the importance of tubular cell phenotype changes in the pathogenesis of DN. These findings could facilitate a better understanding of this complex disease and potentially open new avenues for the design of novel therapeutic approaches to DN.

MicroRNA-10b promotes arthritis development by disrupting CD4+ T cell subtypes

Rheumatoid arthritis (RA) is an inflammation-involved disorder and features the disruption of CD4⁺ T lymphocytes. Herein, we describe that microRNA-10b-5p (miR-10b) promotes RA progression by disrupting the balance between subsets of CD4⁺ T cells. MiR-10b-deficient mice protected against collagen antibody-induced arthritis (CAIA) model. RNA sequencing results indicated that disordered genes in miR-10b^−/− CAIA model are closely associated with CD4⁺ T cells differentiation. Moreover, miR-10b mimics promoted Th1/Th17 and suppressed Th2/Treg cells differentiation, whereas miR-10b inhibitor induced contrary effects. In addition, GATA3 and PTEN was confirmed as two targets of miR-10b, and GATA3 siRNA could increase Th1 and reduce Th2 cells meanwhile PTEN siRNA could increase Th17 and decrease Treg cells. Furthermore, miR-10b inhibitor significantly ameliorated collagen-induced arthritis (CIA) development by attenuating the dysfunctional CD4⁺ T cell subpopulations. The present findings suggest that miR-10b could disrupt the balance of CD4⁺ T subsets, while suppressed miR-10b could attenuate the severity of experimental arthritis, which provided us a novel mechanistic and therapeutic insight into the RA.

Molecular Mechanisms of Immunosenescene and Inflammaging: Relevance to the Immunopathogenesis and Treatment of Multiple Sclerosis

Aging is characterized, amongst other features, by a complex process of cellular senescence involving both innate and adaptive immunity, called immunosenescence and associated to inflammaging, a low-grade chronic inflammation. Both processes fuel each other and partially explain increasing incidence of cancers, infections, age-related autoimmunity, and vascular disease as well as a reduced response to vaccination. Multiple sclerosis (MS) is a lifelong disease, for which considerable progress in disease-modifying therapies (DMTs) and management has improved long-term survival. However, disability progression, increasing with age and disease duration, remains. Neurologists are now involved in caring for elderly MS patients, with increasing comorbidities. Aging of the immune system therefore has relevant implications for MS pathogenesis, response to DMTs and the risks mediated by these treatments. We propose to review current evidence regarding markers and molecular mechanisms of immunosenescence and their relevance to understanding MS pathogenesis. We will focus on age-related changes in the innate and adaptive immune system in MS and other auto-immune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. The consequences of these immune changes on MS pathology, in interaction with the intrinsic aging process of central nervous system resident cells will be discussed. Finally, the impact of immunosenescence on disease evolution and on the safety and efficacy of current DMTs will be presented.

Serum miR-34a-5p and miR-199a-3p as new biomarkers of neonatal sepsis

Background

Neonatal sepsis is a serious condition. Recent clinical studies have indicated that microRNAs (miRNAs) are key players in the pathogenesis of sepsis, which could be used as biomarkers for this condition.

Patients and methods

A total of 90 neonates with sepsis and 90 healthy neonates were enrolled in this study. qRT-PCR was performed to measure the expression levels of serum miR-34a-5p and miR-199a-3p.

Results

miR-34a-5p and miR-199a-3p serum levels were significantly reduced in neonates with sepsis compared with those in healthy neonates (P = 0.006 and P = 0.001, respectively). Significant correlations of miR-34a-5p and miR-199a-3p with each of TLC, RDW, RBS, and C-reactive protein (CRP) as well as SNAPII were observed, indicating their associations with the severity of neonatal sepsis.

Conclusion

miR-34a-5p and miR-199a-3p may be useful as novel biomarkers in neonatal sepsis and may provide a new direction for its treatment.

Regulatory T cell function in autoimmune disease

Autoimmune diseases are characterized by a failure of tolerance to own body components resulting in tissue damage. Regulatory T cells are gatekeepers of tolerance. This review focusses on the function and pathophysiology of regulatory T cells in the context of autoimmune diseases including rheumatoid and juvenile idiopathic arthritis as well as systemic lupus erythematosus with an overview over current and future therapeutic options to boost Treg function.

•

Regulatory T cells are critical mediators of immune tolerance and critically depend on external IL-2.

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Tregs are expanded during inflammation, where the local milieu enhances resistance to suppression in T effector cells.

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Human Tregs are characterized by different markers, which hampers the comparability of studies in patients with autoimmunity.

MicroRNA-34a in coronary heart disease: Correlation with disease risk, blood lipid, stenosis degree, inflammatory cytokines, and cell adhesion molecules

Background

MicroRNA‐34a (miR‐34a) plays an essential role in regulating blood lipid, inflammation, cell adhesion molecules, and atherosclerosis, the latter factors are closely involved in the etiology of coronary heart disease (CHD). However, the clinical value of miR‐34a in CHD patients' management is rarely reported. Hence, this study aimed to assess the correlation of miR‐34a with disease risk, blood lipid, coronary artery stenosis, inflammatory cytokines, and cell adhesion molecules of CHD.

Methods

A total of 203 CHD patients and 100 controls were recruited in this study, then their plasma samples were collected to detect the miR‐34a by reverse transcription quantitative polymerase chain reaction. Furthermore, serum samples from CHD patients were obtained for inflammatory cytokines and cell adhesion molecule measurement by enzyme‐linked immunosorbent assay.

Results

MiR‐34a was elevated in CHD patients compared to controls (p < 0.001) and it disclosed a good diagnostic value of CHD (area under curve: 0.899, 95% confidence interval: 0.865–0.934). Besides, miR‐34a positively correlated with triglyceride (p < 0.001), total cholesterol (p = 0.022) and low‐density lipoprotein cholesterol (p = 0.004), but not with high‐density lipoprotein cholesterol (p = 0.110) in CHD patients. Moreover, miR‐34a associated with Gensini score in CHD patients (p < 0.001). As to inflammation‐related indexes and cell adhesion molecules, MiR‐34a expression was positively linked with C‐reactive protein (p < 0.001), tumor necrosis factor alpha (p = 0.005), interleukin (IL)‐1β (p = 0.020), IL‐17A (p < 0.001), vascular cell adhesion molecule‐1 (p < 0.001), and intercellular adhesion molecule‐1 (p = 0.010) in CHD patients, but not with IL‐6 (p = 0.118) and IL‐10 (p = 0.054).

Conclusion

MiR‐34a might serve as a biomarker in assistance of diagnosis and management of CHD.

Association of microRNA-34a rs2666433 (A/G) Variant with Systemic Lupus Erythematosus in Female Patients: A Case-Control Study

Several microRNAs (miRNAs) are associated with autoimmune disease susceptibility and phenotype, including systemic lupus erythematosus (SLE). We aimed to explore for the first time the role of the miRNA-34a gene (MIR34A) rs2666433A > G variant in SLE risk and severity. A total of 163 adult patients with SLE and matched controls were recruited. Real-Time allelic discrimination PCR was applied for genotyping. Correlation with disease activity and clinic-laboratory data was done. The rs2666433 variant conferred protection against SLE development under heterozygous [A/G vs. G/G; OR = 0.57, 95%CI = 0.34-0.95], homozygous [A/A vs. G/G; OR = 0.52, 95%CI = 0.29-0.94], dominant [A/G + A/A vs. GG; OR = 0.55, 95%CI = 0.35-0.88], and log-additive [OR = 0.71, 95%CI = 0.53-0.95] models. Data stratification by sex revealed a significant association with SLE development in female participants under heterozygous/homozygous models (p-interaction = 0.004). There was no clear demarcation between SLE patients carrying different genotypes regarding the disease activity index or patients stratified according to lupus nephritis. Enrichment analysis confirmed the implication of MIR34A in the SLE pathway by targeting several genes related to SLE etiopathology. In conclusion, although the MIR34A rs2666433 variant conferred protection against developing SLE disease in the study population, it showed no association with disease activity. Replication studies in other populations are warranted.

Glucose Metabolism Reprogramming of Regulatory T Cells in Concanavalin A-Induced Hepatitis

Autoimmune hepatitis (AIH) is an inflammatory liver disease caused by a dysregulated immune response. Although the pathogenesis of AIH remains unclear, impaired regulatory T cells (Tregs) have been considered a driver of AIH development. Unlike autoreactive T cells, Tregs mainly utilize oxidative phosphorylation (OXPHOS) as their energy supply. Elevated glycolysis has been reported to limit the suppressive functions of Tregs. However, whether glucose metabolism reprogramming in Tregs is involved in AIH etiology remains unknown. The aim of this study was to examine alternations in Treg numbers and functions in AIH patients and concanavalin A (Con A)-induced hepatitis, while exploring associations between impaired Tregs and glucose metabolism. The frequency of Tregs was decreased in the peripheral blood but increased in liver biopsies of AIH patients. Moreover, immunosuppressive therapy rescued circulating Tregs in AIH. In Con A-induced immune hepatitis, enhanced intrahepatic Treg accumulation was observed over time, accompanied by reduced splenic Treg numbers. To investigate whether functional impairment of Tregs occurs in AIH, Tregs were isolated from experimental AIH (EAH) model mice and normal controls and the former displayed downregulated mRNA levels of FOXP3, CTLA4, CD103, TIGIT, CD39, and CD73. EAH model-derived Tregs also produced fewer anti-inflammatory mediators (TGF-β and IL-35) than control Tregs. Moreover, enhanced glycolysis and reduced OXPHOS were found in Tregs from EAH model mice, as reflected by elevated levels of key glycolytic enzymes (HK2, PK-M2, and LDH-A) and a decreased ATP concentration. This study revealed a decreased peripheral Treg frequency and abnormal intrahepatic Treg infiltration in AIH. It is first reported that glucose metabolism reprogramming is associated with decreases and functional impairments in the Treg population, promoting AIH development. Targeting glucose metabolism may provide novel insights for the treatment of AIH.

Dysfunctions, Molecular Mechanisms, and Therapeutic Strategies of Regulatory T Cells in Rheumatoid Arthritis

Regulatory T cells (Tregs) represent a distinct subpopulation of CD4⁺ T lymphocytes that promote immune tolerance and maintain immune system homeostasis. The dysfunction of Tregs is tightly associated with rheumatoid arthritis (RA). Although the complex pathogenic processes of RA remain unclear, studies on Tregs in RA have achieved substantial progress not only in fundamental research but also in clinical application. This review discusses the current knowledge of the characterizations, functions, and molecular mechanisms of Tregs in the pathogenesis of RA, and potential therapies for these disorders are also involved.

Enhanced Expression of miR-34a Enhances Escherichia coli Lipopolysaccharide-Mediated Endometritis by Targeting LGR4 to Activate the NF-κB Pathway

BACKGROUND

Persistent endometritis caused by bacterial infections has lethal effects on the reproductive performance of dairy cattle, which compromises animal welfare and delays or prevents pregnancy. The microRNA (miRNA) miR-34 family plays a pivotal role in the inflammatory process; however, the precise mechanism of miR-34a in endometritis has not been thoroughly elucidated to date.

METHODS

In this study, the endometrium of cows diagnosed with endometritis was harvested for bacterial culture and Gram staining to evaluate bacterial contamination of the uterus. Based on this, a bovine endometrial epithelial cell (BEND) inflammation model and a mouse model stimulated with lipopolysaccharide (LPS) in vitro and in vivo were constructed. Cell viability was assessed by CCK-8, trypan blue staining, and flow cytometry. H&E was applied to histopathological analysis. Immunohistochemical, immunofluorescence, qRT-PCR, and western blot assays were performed to measure the mRNA and protein expression of relevant genes. Online databases, plasmid construction, and dual-luciferase reporter gene assays were used to predict and validate the interaction between miR-34a and its target gene LGR4. Finally, mice were injected vaginally with a local antagomir to validate the role of miR-34a in murine uterine inflammation.

RESULTS

In this study, we observed that Gram-negative bacteria, represented by Escherichia coli, are the predominant pathogenic agents responsible for the recurrent occurrence of endometritis in dairy cows. Further, miR-34a was found to repress the expression of LGR4 by targeting the 3' untranslated region (3'UTR) of LGR4. miR-34a was upregulated in bovine uterine tissues and bovine endometrial epithelial cells stimulated with LPS. miR-34a induced the release of the proinflammatory cytokines IL-1β, IL-6, and TNF-α by activating the phosphorylation of NF-κB p65. Furthermore, IL-1β upregulated miR-34a transcription and downregulated LGR4 expression in an IL-1β-dependent manner.

CONCLUSIONS

Taken together, our study confirmed that miR-34a is regulated by IL-1β and suppresses the level of the LGR4 3'UTR, which in turn exacerbates the inflammatory response. Thus, the knockdown of miR-34a might be a new direction for the treatment of endometritis.

Immunological Involvement of MicroRNAs in the Key Events of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an archetype autoimmune disease characterized by a myriad of immunoregulatory abnormalities that drives injury to multiple tissues and organs. Due to the involvement of various immune cells, inflammatory cytokines, and related signaling pathways, researchers have spent a great deal of effort to clarify the complex etiology and pathogenesis of SLE. Nevertheless, current understanding of the pathogenesis of SLE is still in the early stages, and available nonspecific treatment options for SLE patients remain unsatisfactory. First discovered in 1993, microRNAs (miRNAs) are small RNA molecules that control the expression of 1/3 of human genes at the post-transcriptional level and play various roles in gene regulation. The aberrant expression of miRNAs in SLE patients has been intensively studied, and further studies have suggested that these miRNAs may be potentially relevant to abnormal immune responses and disease progression in SLE. The aim of this review was to summarize the specific miRNAs that have been observed aberrantly expressed in several important pathogenetic processes in SLE, such as DCs abnormalities, overactivation and autoantibody production of B cells, aberrant activation of CD4⁺ T cells, breakdown of immune tolerance, and abnormally increased production of inflammatory cytokines. Our summary highlights a novel perspective on the intricate regulatory network of SLE, which helps to enrich our understanding of this disorder and ignite future interest in evaluating the molecular regulation of miRNAs in autoimmunity SLE.

Oxidized high-density lipoprotein enhances endocrine disorders and ovarian damage in rats

Previous findings have highlighted the association between oxidized high‐density lipoprotein (ox‐HDL) and polycystic ovary syndrome (PCOS) development; however, the underlying mechanism remains unclear. Under such context, the present study aimed to investigate the mechanism underlying the involvement of ox‐HDL in PCOS in relation to the p65/micro‐RNA‐34a (miR‐34a)/FOS axis. PCOS rat models were established with the injection of dehydroepiandrosterone (6 mg/100 g body weight). Both PCOS‐modelled rats and granulosa cells (GCs) were received treatment with ox‐HDL in order to identify its role in PCOS. Next, apoptosis and viability of GCs were detected with the application of TdT‐mediated dUTP Nick‐End Labeling and flow cytometry and Cell counting kit‐8, respectively. A series of assays were performed to determine the interaction among ox‐HDL, p65, miR‐34a, FOS and nuclear factor‐κB (NF‐κB). The results revealed high expression of ox‐HDL in PCOS, and enhanced endocrine disorders and ovarian damage in rats. ox‐HDL promoted apoptosis of GCs and decreased its viability. ox‐HDL activated NF‐κB pathway and induced p65 phosphorylation to promote miR‐34a expression. miR‐34a targeted and inhibited FOS expression. In conclusion, our findings suggested that ox‐HDL promoted the activation of p65 and transcription of miR‐34a, which stimulated apoptosis of GCs and inhibited expression of FOS, resulting in the overall acceleration of PCOS development.

Insights into the biology and therapeutic implications of TNF and regulatory T cells

Treatments that block tumour necrosis factor (TNF) have major beneficial effects in several autoimmune and rheumatic diseases, including rheumatoid arthritis. However, some patients do not respond to TNF inhibitor treatment and rare occurrences of paradoxical disease exacerbation have been reported. These limitations on the clinical efficacy of TNF inhibitors can be explained by the differences between TNF receptor 1 (TNFR1) and TNFR2 signalling and by the diverse effects of TNF on multiple immune cells, including FOXP3⁺ regulatory T cells. This basic knowledge sheds light on the consequences of TNF inhibitor therapies on regulatory T cells in treated patients and on the limitations of such treatment in the control of diseases with an autoimmune component. Accordingly, the next generation of drugs targeting TNF is likely to be based on agents that selectively block the binding of TNF to TNFR1 and on TNFR2 agonists. These approaches could improve the treatment of rheumatic diseases in the future.

MicroRNA-26b-5p alleviates murine collagen-induced arthritis by modulating Th17 cell plasticity

Rheumatoid arthritis (RA) is a chronic autoimmune disease, and the abnormal differentiation of IL-17-producing T helper (Th17) cells is an important factor in the pathogenesis. Previous studies have shown that microRNAs (miRNAs, miR) act as key regulators of Th17 cells. However, the effects of miRNAs on Th17 cell differentiation and plasticity in RA are not clear. In this study, not only low miR-26b-5p expression and high IL-17A level were observed in the peripheral blood of RA patients, but also the negative correlation between miR-26b-5p and IL-17A was explored. The changes in collagen-induced arthritis (CIA) mice were consistent with those in RA patients. The results of in vitro experiments showed that miR-26b-5p mainly inhibited the initial differentiation of Th17 cells but did not impact the differentiation of induced-Treg into Th17-like cells. Meanwhile, miR-26b-5p mimics treatment alleviated inflammatory responses and reduced Th17 proportion in CIA mice. These results indicated that miR-26b-5p could alleviate the development of mice CIA by inhibiting the excessive Th17 cells, and that miR-26b-5p could modulate the plasticity of Th17 cell differentiation in RA, mainly block the initial differentiation. This may provide a novel strategy for the clinical treatment of RA.

Identification of diagnostic genes and vital microRNAs involved in rheumatoid arthritis: based on data mining and experimental verification

Background

The pathogenesis of rheumatoid arthritis (RA) is complex. This study aimed to identify diagnostic biomarkers and transcriptional regulators that underlie RA based on bioinformatics analysis and experimental verification.

Material and Methods

We applied weighted gene co-expression network analysis (WGCNA) to analyze dataset GSE55457 and obtained the key module most relevant to the RA phenotype. We then conducted gene function annotation, gene set enrichment analysis (GSEA) and immunocytes quantitative analysis (CIBERSORT). Moreover, the intersection of differentially expressed genes (DEGs) and genes within the key module were entered into the STRING database to construct an interaction network and to mine hub genes. We predicted microRNA (miRNA) using a web-based tool (miRDB). Finally, hub genes and vital miRNAs were validated with independent GEO datasets, RT-qPCR and Western blot.

Results

A total of 367 DEGs were characterized by differential expression analysis. The WGCNA method divided genes into 14 modules, and we focused on the turquoise module containing 845 genes. Gene function annotation and GSEA suggested that immune response and inflammatory signaling pathways are the molecular mechanisms behind RA. Nine hub genes were screened from the network and seven vital regulators were obtained using miRNA prediction. CIBERSORT analysis identified five cell types enriched in RA samples, which were closely related to the expression of hub genes. Through ROC curve and RT-qPCR validation, we confirmed five genes that were specific for RA, including CCL25, CXCL9, CXCL10, CXCL11, and CXCL13. Moreover, we selected a representative gene (CXCL10) for Western blot validation. Vital miRNAs verification showed that only the differences in has-miR-573 and has-miR-34a were statistically significant.

Conclusion

Our study reveals diagnostic genes and vital microRNAs highly related to RA, which could help improve our understanding of the molecular mechanisms underlying the disorder and provide theoretical support for the future exploration of innovative therapeutic approaches.

miRNAs Alter T Helper 17 Cell Fate in the Pathogenesis of Autoimmune Diseases

T helper 17 (Th17) cells are characterized by the secretion of the IL-17 cytokine and are essential for the immune response against bacterial and fungal infections. Despite the beneficial roles of Th17 cells, unrestrained IL-17 production can contribute to immunopathology and inflammatory autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Although these diverse outcomes are directed by the activation of Th17 cells, the regulation of Th17 cells is incompletely understood. The discovery that microRNAs (miRNAs) are involved in the regulation of Th17 cell differentiation and function has greatly improved our understanding of Th17 cells in immune response and disease. Here, we provide an overview of the biogenesis and function of miRNA and summarize the role of miRNAs in Th17 cell differentiation and function. Finally, we focus on recent advances in miRNA-mediated dysregulation of Th17 cell fate in autoimmune diseases.

Sublytic C5b-9 induces glomerular mesangial cell proliferation via ERK1/2-dependent SOX9 phosphorylation and acetylation by enhancing Cyclin D1 in rat Thy-1 nephritis

Glomerular mesangial cell (GMC) proliferation is a histopathological alteration in human mesangioproliferative glomerulonephritis (MsPGN) or in animal models of MsPGN, e.g., the rat Thy-1 nephritis (Thy-1N) model. Although sublytic C5b-9 assembly on the GMC membrane can trigger cell proliferation, the mechanisms are still undefined. We found that sublytic C5b-9-induced rat GMC proliferation was driven by extracellular signal-regulated kinase 1/2 (ERK1/2), sry-related HMG-box 9 (SOX9), and Cyclin D1. Here, ERK1/2 phosphorylation was a result of the calcium influx-PKC-α-Raf-MEK1/2 axis activated by sublytic C5b-9, and Cyclin D1 gene transcription was enhanced by ERK1/2-dependent SOX9 binding to the Cyclin D1 promoter (-582 to -238 nt). In addition, ERK1/2 not only interacted with SOX9 in the cell nucleus to mediate its phosphorylation at serine residues 64 (a new site identified by mass spectrometry) and 181 (a known site), but also indirectly induced SOX9 acetylation by elevating the expression of general control non-repressed protein 5 (GCN5), which together resulted in Cyclin D1 synthesis and GMC proliferation. Moreover, our in vivo experiments confirmed that silencing these genes ameliorated the lesions of Thy-1N rats and reduced SOX9 phosphorylation, acetylation and Cyclin D1 expression. Furthermore, the renal tissue sections of MsPGN patients also showed higher phosphorylation or expression of ERK1/2, SOX9, and Cyclin D1. In summary, these findings suggest that sublytic C5b-9-induced GMC proliferation in rat Thy-1N requires SOX9 phosphorylation and acetylation via enhanced Cyclin D1 gene transcription, which may provide a new insight into human MsPGN pathogenesis.

Protective effect of FOXP3-mediated miR-146b-5p/Robo1/NF-κB system on lipopolysaccharide-induced acute lung injury in mice

Background

As a key transcription factor, forkhead box protein 3 (FOXP3) plays an important role in the development and function of natural cluster of differentiation 4 [CD4 (+)] regulatory T cells (Treg cells). However, the function of FOXP3 in Lipopolysaccharide (LPS)-induced acute lung injury (ALI) through regulating miR-146b-5p is unclear. This research aimed to disclose the regulatory effect of the FOXP3-mediated miR-146b-5p/Roundabout 1 (Robo1)/NF-κB system on LPS-induced ALI in mice.

Methods

The mice were subjected to 5 mg/kg of LPS via intratracheal instillation to induce ALI and generate the ALI model. Mice was divided into five group, including control group, ALI group, ALI + FOXP3 group, the ALI + miR antagomir group and ALI + miR antagomir+ FOXP3 group. Lung tissue injury were detected by hematoxylin and eosin (HE) staining. Lung wet/dry weight ratio, total cells in bronchoalveolar lavage fluid (BALF), total protein in BALF and the polymorphonuclear leukocyte (PMN) in BALF were detected. The levels of tumor necrosis factor-α (TNF-α), Interleukin 6 (IL-6) and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA) kit. The dual-luciferase reporter assay were used to detect the target relationship between FOXP3 and Robo1. Mice was divided into five group, including control group, ALI group, ALI + FOXP3 group, ALI + Robo1 group and ALI + FOXP3+ Robo1 group. The protein levels of FOXP3, Robo1 and p-p65 were detected by western bolt. The mRNA levels of miR-146b-5p and Robo1 were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Results

Although protein expression levels of FOXP3 were significantly down-regulated in the ALI model, the increased FOXP3 levels promoted an increase in miR-146b-5p. Compared with the control group, the ALI model group exhibited severe histopathologic injury, such as thickening of the alveolar wall, pulmonary congestion, and decreased alveolar numbers. By mediating the overexpression of miR-146b-5p, FOXP3 also increased alveolar clearance and inhibited inflammatory responses in the ALI model. Importantly, Robo1 is a potential target of miR-146b-5p.

Conclusions

FOXP3 could inhibit NF-κB activation, reduce lung pathological damage, and inhibit inflammatory responses by mediating the miR-146b-5p/Robo1/NF-κB system in the ALI model. These results may provide a new potential target for the treatment of ALI disease.