MicroRNA profiling in Chinese children with Henoch-Schonlein purpura and association between selected microRNAs and inflammatory biomarkers

Human bone marrow mesenchymal stem cell-derived extracellular vesicles restore Th17/Treg homeostasis in periodontitis via miR-1246

T-cell-mediated immunity is crucial in the immunopathology of periodontitis. The restoration of the homeostasis between the T helper cell 17 (Th17) and regulatory T cell (Treg) subsets by extracellular vesicles (EVs) obtained from human bone marrow stem cells (hBMSCs) promotes new bone formation and suppresses inflammation. Uncovering the functions of hBMSC-derived EVs in the immune microenvironment of periodontal tissue and their underlying regulatory mechanisms may shed new light on developing potential cell-free immunotherapies for periodontal regeneration. Here, we reported that the Th17/Treg ratio elevated in peripheral blood from periodontitis patients. Furthermore, we found that hBMSC-derived EVs could reduce the Th17/Treg ratio in CD4+ T cells from periodontitis patients in vitro and ameliorate conditions of experimental periodontitis in mice. Additionally, by investigating the differentially expressed miRNAs and target genes in EVs from hBMSCs stimulated with Porphyromonas gingivalis LPS using miRNA sequencing, we found that EV-miR-1246 is highly effective at downregulating the ratio of Th17/Treg in vitro. Mechanistically, EV-miR-1246 suppressed expression of its potential target angiotensin-converting enzyme 2 (ACE2) and increased the p-Yes-associated protein (YAP)1/YAP1 ratio in CD4+ T cells. Our results indicated that hBMSC-derived EVs improve periodontitis via miR-1246, consequently downregulating Th17/Treg ratio, and represented a promising therapeutic target for precision treatment in periodontitis.

MicroRNA-1246 Inhibits NFATc1 Phosphorylation and Regulates T Helper 17 Cell Activation in the Pathogenesis of Severe Alopecia Areata

BACKGROUND

We found microRNA (miR)-1246 to be significantly differentially expressed between severe active alopecia areata (AA) patients and healthy individuals.

OBJECTIVE

To explore the role and mechanism of miR-1246 in severe AA.

METHODS

Expression of miR-1246, dual-specific tyrosine phosphorylation-regulated kinase 1A (DYRK1A), and nuclear factor of activated T cells 1c (NFATc1) in peripheral CD4⁺ T cells and in scalp tissues of patients were detected using RT-qPCR, Western blot, and immunohistochemistry assays. Peripheral CD4⁺ T cells from the AA patients were transfected with lentiviral vectors overexpressing miR-1246. RT-qPCR and Western blot analysis were used to measure mRNA or protein expression of retinoic-acid-receptor-related orphan nuclear receptor gamma (ROR-γt), interleukin (IL)-17, DYRK1A, NFATc1, and phosphorylated NFATc1. Flow cytometry was used to assay the CD4⁺IL-17⁺ cells proportion. ELISA was used to measure cytokine levels.

RESULTS

miR-1246 levels decreased and DYRK1A and NFATc1 mRNA levels significantly increased in the peripheral CD4⁺ T cells and scalp tissues of severe active AA samples. NFATc1 protein expression was also significantly increased in the peripheral CD4⁺ T cells but not in the scalp tissues. NFATc1 positive cells were mainly distributed among infiltrating inflammatory cells around hair follicles. In peripheral CD4⁺ T cells of severe active AA, overexpression of miR-1246 resulted in significant downregulation of DYRK1A, NFATc1, ROR-γt, and IL-17 mRNA and phosphorylated NFATc1 protein, as well as a decrease in the CD4⁺IL-17⁺ cells proportion and the IL-17F level.

CONCLUSION

miR-1246 can inhibit NFAT signaling and Th17 cell activation, which may be beneficial in the severe AA treatment.

Regulatory T Cells in Autoimmune Vasculitis

Blood vessels are indispensable for host survival and are protected from inappropriate inflammation by immune privilege. This protection is lost in patients with autoimmune vasculitides, a heterogeneous group of diseases causing damage to arteries, arterioles, and capillaries. Vasculitis leads to vascular wall destruction and/or luminal occlusion, resulting in hemorrhage and tissue ischemia. Failure in the quantity and quality of immunosuppressive regulatory T cells (Treg) has been implicated in the breakdown of the vascular immune privilege. Emerging data suggest that Treg deficiencies are disease-specific, affecting distinct pathways in distinct vasculitides. Mechanistic studies have identified faulty CD8+ Tregs in Giant Cell Arteritis (GCA), a vasculitis of the aorta and the large aortic branch vessels. Specifically, aberrant signaling through the NOTCH4 receptor expressed on CD8+ Treg cells leads to rerouting of intracellular vesicle trafficking and failure in the release of immunosuppressive exosomes, ultimately boosting inflammatory attack to medium and large arteries. In Kawasaki’s disease, a medium vessel vasculitis targeting the coronary arteries, aberrant expression of miR-155 and dysregulated STAT5 signaling have been implicated in undermining CD4+ Treg function. Explorations of mechanisms leading to insufficient immunosuppression and uncontrolled vascular inflammation hold the promise to discover novel therapeutic interventions that could potentially restore the immune privilege of blood vessels and pave the way for urgently needed innovations in vasculitis management.

Differences in Manifestations and Gut Microbiota Composition Between Patients With Different Henoch-Schonlein Purpura Phenotypes

Background

Gut microbiota plays an important role in the pathogenesis of immune-mediated diseases. However, the complex pathogenesis of Henoch-Schonlein Purpura (HSP) remains elusive. This study aimed to characterize the gut microbiota in HSP patients and explore the potential association between gut microbiota composition and phenotypic changes in HSP.

Methods

16SrRNA gene sequencing and bioinformatic analyses were performed using total DNA extracted from the fecal microbiota of 34 children with HSP, including 18 primary cases, 16 recurrent cases, and 23 healthy children.

Results

The diversity indexes showed significant differences in the microbial community among the primary HSP groups, the recurrent HSP group and healthy controls. The abundance of Escherichia-Shigella in the recurrent HSP group was significantly higher than that in the primary HSP group, and the constructed ROC curve had an AUC value of 0.750. According to the Spearman correlation analysis, the abundance of Bacteroides was positively associated with the serum IgG level in children with HSP, while the abundance of Lachnoclostridium was negatively correlated with the complement component 3 (C3). The diversity indexes of gut microbiota in the HSP group with abdominal symptoms were higher than those in the HSP group without GI involvement, and also higher than those in the healthy control group. In the HSP group with GI involvement, the abundance of Faecalibacterium was decreased, while the abundance of Streptococcus and Fusobacteria was increased, compared to the HSP group without GI involvement.

Conclusions

The gut microbiota of children with HSP was different from that of healthy children. The genus Escherichia-Shigella has a diagnostic value for HSP recurrence. Bacteroides and Lachnoclostridium may affect IgG and complement C3 levels in children with HSP. Abdominal symptoms in HSP children were related to gut microbiota (Streptococcus and butyric acid-producing bacteria).