Decreasing lncRNA PVT1 causes Treg/Th17 imbalance via NOTCH signaling in immune thrombocytopenia

Review on Long Non-Coding RNAs as Biomarkers and Potentially Therapeutic Targets for Bacterial Infections

The confrontation between humans and bacteria is ongoing, with strategies for combating bacterial infections continually evolving. With the advancement of RNA sequencing technology, non-coding RNAs (ncRNAs) associated with bacterial infections have garnered significant attention. Recently, long ncRNAs (lncRNAs) have been identified as regulators of sterile inflammatory responses and cellular defense against live bacterial pathogens. They are involved in regulating host antimicrobial immunity in both the nucleus and cytoplasm. Increasing evidence indicates that lncRNAs are critical for the intricate interactions between host and pathogen during bacterial infections. This paper emphatically elaborates on the potential applications of lncRNAs in clinical hallmarks, cellular damage, immunity, virulence, and drug resistance in bacterial infections in greater detail. Additionally, we discuss the challenges and limitations of studying lncRNAs in the context of bacterial infections and highlight clear directions for this promising field.

The miR-641-STIM1 and SATB1 axes play important roles in the regulation of the Th17/Treg balance in ITP

Immune thrombocytopenia (ITP) is an autoimmune disease caused by T-cell dysfunction. Recently, several studies have shown that a disturbed Th17/Treg balance contributes to the development of ITP. MicroRNAs (miRNAs) are small noncoding RNA moleculesthat posttranscriptionally regulate gene expression. Emerging evidences have demonstrated that miRNAs play an important role in regulating the Th17/Treg balance. In the present study, we found that miR-641 was upregulated in ITP patients. In primary T cells, overexpression of miR-641 could cause downregulation of its target genes STIM1 and SATB1, thus inducing a Th17 (upregulated)/Treg (downregulated) imbalance. Inhibition of miR-641 by a miR-641 sponge in primary T cells of ITP patients or by antagomiR-641 in an ITP murine model could cause upregulation of STIM1 and SATB1, thus restoring Th17/Treg homeostasis. These results suggested that the miR-641-STIM/SATB1 axis plays an important role in regulating the Th17/Treg balance in ITP.

Resveratrol inhibits AhR/Notch axis and reverses Th17/Treg imbalance in purpura by activating Foxp3

Background

Resveratrol has been reported to reverse the imbalance of T helper 17/regulatory T (Th17/Treg) by inhibiting the aryl hydrocarbon receptor pathway to treat immune thrombocytopenia. However, the regulation mechanism of the Notch signaling pathway by resveratrol has not been reported in purpura. This study is aimed to explore the mechanism of resveratrol ultrafine nanoemulsion (Res-mNE) in immune thrombocytopenia.

Methods

The immune thrombocytopenia mouse model was constructed to explore the effect of RES-mNE on immune thrombocytopenia. Cluster of differentiation 4 (CD4+) T cells were isolated and treated with different medications. CD4+ T cells were induced to differentiate into Th17 cells and Treg cells. Flow cytometry was used to detect the proportion of Th17 cells and Treg cells. The secretion was measured by the enzyme-linked immunosorbent assay (ELISA). Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blot were used to detect the mRNA and protein levels.

Results

Th17 cells, IL-17A and IL-22 increased in the immune thrombocytopenia mouse model, and the Treg cells and IL-10 decreased. Res-mNE promoted Treg cell differentiation and IL-10 secretion in CD4+ T cells while inhibiting Th17 cell differentiation and IL-17A and IL-22 levels. The AhR activator 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) reversed the effect of Res-mNE. Notch inhibitors reduced the ratio of Th17/Treg differentiation. Res-mNE activated the expression of Foxp3 by mediating AhR/Notch signaling to reverse the imbalance of Th17/Treg differentiation in immune thrombocytopenia.

Conclusion

Taken together, our findings demonstrated that RES-mNE inhibited the AhR/Notch axis and reversed Th17/Treg imbalance by activating Foxp3.

Is Th17-Targeted Therapy Effective in Systemic Lupus Erythematosus?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a broad spectrum of clinical manifestations. The proposed pathophysiological hypotheses of SLE are numerous, involving both innate and adaptive abnormal immune responses. SLE is characterized by the overproduction of different autoantibodies that form immune complexes, which cause damage in different organs. Current therapeutic modalities are anti-inflammatory and immunosuppressive. In the last decade, we have witnessed the development of many biologicals targeting different cytokines and other molecules. One of them is interleukin-17 (IL-17), a central cytokine of a proinflammatory process that is mediated by a group of helper T cells called Th17. Direct inhibitors of IL-17 are used in psoriatic arthritis, spondyloarthritis, and other diseases. Evidence about the therapeutic potential of Th17-targeted therapies in SLE is scarce, and probably the most promising is related to lupus nephritis. As SLE is a complex heterogeneous disease with different cytokines involved in its pathogenesis, it is highly unlikely that inhibition of only one molecule, such as IL-17, will be effective in the treatment of all clinical manifestations. Future studies should identify SLE patients that are eligible for Th17-targeted therapy.

Regulatory factors involved in Th17/Treg cell balance of immune thrombocytopenia

Immune thrombocytopenia is a common heterogeneous autoimmune disease that is characterized by decreasing peripheral blood platelet counts and increasing risk of bleeding. Studies have shown that an imbalance between T helper 17 (Th17) and Regulatory T (Treg) cells differentiated from CD4+T-cells is a key factor influencing the development and pathogenesis of immune thrombocytopenia. Th17 cells promote the development of chronic inflammatory disorders and induce autoimmune diseases, whereas Treg cells regulate immune homeostasis and prevent autoimmune diseases. Several regulators affecting the production and maintenance of these cells are also essential for proper regulation of Th17/Treg balance; these regulatory factors include cell surface proteins, miRNAs, and cytokine signaling. In this review, we focus on the function and role of balance between Th17 and Treg cells in immune thrombocytopenia, the regulatory factors, and therapeutic goals of this balance in immune thrombocytopenia.

MetBil as a novel molecular regulator in ischemia-induced cardiac fibrosis via METTL3-mediated m6A modification

Cardiac fibrosis is a common pathological manifestation in multiple cardiovascular diseases and often results in myocardial stiffness and cardiac dysfunctions. LncRNA (long noncoding RNA) participates in a number of pathophysiological processes. However, its role in cardiac fibrosis remains unclear. The purpose of this study was to investigate the role and molecular mechanism of MetBil in regulating cardiac fibrosis. Our data showed that METTL3 binding lncRNA (MetBil) was significantly increased both in fibrotic tissue following myocardial infarction (MI) in mice and in cardiac fibroblasts (CFs) exposed to TGF-β1 (20 ng/mL) or 20% FBS. Overexpression of MetBil augmented collagen deposition, CF proliferation and activation while silencing MetBil exhibited the opposite effects. Importantly, heterozygous knockout of MetBil alleviated cardiac fibrosis and improved cardiac function after MI. RNA pull-down and RNA-binding protein immunoprecipitation assay showed that METTL3 is a direct downstream target of MetBil; consistently, MetBil and METTL3 were co-localized in both the nucleus and cytoplasm of CFs. Interestingly, MetBil regulated METTL3 expression at protein level, but not mRNA level, in ubiquitin-proteasome pathway. Enforced expression of METTL3 canceled the antifibrotic effects of silencing MetBil reflected by increased collagen production, CF proliferation and activation. Most notably, the m6A-modified fibrosis-regulated genes mediated by METTL3 are profoundly involved in the regulation of MetBil in the cardiac fibrosis following MI. Our study reveals that MetBil as a novel regulator of fibrosis promotes cardiac fibrosis via interacting with METTL3 and regulating the expression of the methylated fibrosis-associated genes, providing a new intervening target for fibrosis-associated cardiac diseases.

Scoping Review on Epigenetic Mechanisms in Primary Immune Thrombocytopenia

Immune Thrombocytopenia (ITP) is an autoimmune blood disorder that involves multiple pathways responsible for the homeostasis of the immune system. Numerous pieces of literature have proposed the potential of immune-related genes as diagnostic and prognostic biomarkers, which mostly implicate the role of B cells and T cells in the pathogenesis of ITP. However, a more in-depth understanding is required of how these immune-related genes are regulated. Thus, this scoping review aims to collate evidence and further elucidate each possible epigenetics mechanism in the regulation of immunological pathways pertinent to the pathogenesis of ITP. This encompasses DNA methylation, histone modification, and non-coding RNA. A total of 41 studies were scrutinized to further clarify how each of the epigenetics mechanisms is related to the pathogenesis of ITP. Identifying epigenetics mechanisms will provide a new paradigm that may assist in the diagnosis and treatment of immune thrombocytopenia.

lncRNA PVT1: a novel oncogene in multiple cancers

Long noncoding RNAs are involved in epigenetic gene modification, including binding to the chromatin rearrangement complex in pre-transcriptional regulation and to gene promoters in gene expression regulation, as well as acting as microRNA sponges to control messenger RNA levels in post-transcriptional regulation. An increasing number of studies have found that long noncoding RNA plasmacytoma variant translocation 1 (PVT1) plays an important role in cancer development. In this review of a large number of studies on PVT1, we found that PVT1 is closely related to tumor onset, proliferation, invasion, epithelial–mesenchymal transformation, and apoptosis, as well as poor prognosis and radiotherapy and chemotherapy resistance in some cancers. This review comprehensively describes PVT1 expression in various cancers and presents novel approaches to the diagnosis and treatment of cancer.

Single Nucleotide Polymorphisms of the HIF1A Gene are Associated With Sensitivity of Glucocorticoid Treatment in Pediatric ITP Patients

BACKGROUND

Hypoxia-inducible factor-1α (HIF-1α) plays a crucial role in both innate and adaptive immunity. Emerging evidence indicates that HIF-1α is associated with the inflammation and pathologic activities of autoimmune diseases, suggesting that HIF1α may be involved in immune dysregulation in patients with immune thrombocytopenia (ITP). The purpose of this study was to evaluate whether single nucleotide polymorphisms (SNPs) of the HIF1A gene are associated with susceptibility to ITP and its clinical prognosis including incidence of chronic ITP and glucocorticoid sensitivity.

MATERIALS AND METHODS

This study involved 197 Chinese ITP pediatric patients (discovery cohort) and 220 healthy controls. The Sequenom MassArray system (Sequenom, San Diego, CA) was used to detect 3 SNPs genotypes in the HIF1A gene: rs11549465, rs1957757, and rs2057482. We also used another ITP cohort (N=127) to validate the significant results of SNPs found in the discovery cohort.

RESULTS

The frequencies of the three SNPs did not show any significant differences between the ITP and healthy control groups. The CT genotype at rs11549465 was significantly higher in ITP patients sensitive to glucocorticoid treatment than in those insensitive to glucocorticoid treatment (P=0.025). These results were validated using another ITP cohort (N=127, P=0.033). Moreover, the CC genotype was a risk factor for insensitive to GT the odds ratio (95% confidence interval) was 5.96 (5.23-6.69) in standard prednisone (P=0.0069) and 6.35 (5.33-7.37) in high-dose dexamethasone (P=0.04).

CONCLUSIONS

Although HIF1A gene polymorphisms were not associated with susceptibility to ITP, the CT genotype at rs11549465 was associated with the sensitivity to glucocorticoid treatment of ITP patients, suggesting that the rs11549465 SNP may contribute to the sensitivity of glucocorticoid treatment in pediatric ITP patients.