SNP rs4937333 in the miRNA-5003-Binding Site of the ETS1 3'-UTR Decreases ETS1 Expression

An update on the roles of transcription factor Ets1 in autoimmune diseases

Transcription factors are crucial to regulate gene expression in immune cells and in other cell types. In lymphocytes, there are a large number of different transcription factors that are known to contribute to cell differentiation and the balance between quiescence and activation. One such transcription factor is E26 oncogene homolog 1 (Ets1). Ets1 expression is high in quiescent B and T lymphocytes and its levels are decreased upon activation. The human ETS1 gene has been identified as a susceptibility locus for many autoimmune and inflammatory diseases. In accord with this, gene knockout of Ets1 in mice leads to development of a lupus-like autoimmune disease, with enhanced activation and differentiation of both B cells and T cells. Prior reviews have summarized functional roles for Ets1 based on studies of Ets1 knockout mice. In recent years, numerous additional studies have been published that further validate ETS1 as a susceptibility locus for human diseases where immune dysregulation plays a causative role. In this update, new information that further links Ets1 to human autoimmune diseases is organized and collated to serve as a resource. This update also describes recent studies that seek to understand molecularly how Ets1 regulates immune cell activation, either using human cells and tissues or mouse models. This resource is expected to be useful to investigators seeking to understand how Ets1 may regulate the human immune response, particularly in terms of its roles in autoimmunity and inflammation. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Molecular and Cellular Physiology.

Downregulation of circETS1 disrupts Th17/Treg homeostasis by inhibiting FOXP3 transcription: A new potential biomarker in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease associated with an imbalance of T helper 17 (Th17) to regulatory T cells (Tregs). However, the underlying mechanism remains unclear. Increasing evidence suggests that circular RNAs play a crucial role in SLE. Although circETS1 was discovered 30 years ago, detailed exploration of its functions remains limited. In this study, we measured the expression levels of circETS1 in peripheral blood mononuclear cells (PBMCs) and CD4+ T cells of patients with SLE by quantitative polymerase chain reaction. The impact of circETS1 expression on the Th17/Treg balance and underlying mechanism were evaluated using double-luciferase reporter, gain-/loss-of-function, and rescue assays. Receiver operating characteristic (ROC) curve analysis was conducted to assess the diagnostic value of circETS1. Both circETS1 and FOXP3 expression were downregulated in the PBMCs and CD4+ T cells of patients with SLE (n = 28) compared with those in the cells of healthy controls (n = 20). Mechanistically, we found that circETS1 can bind directly to the microRNA miR-1205, acting as a sponge to upregulate the transcription of FOXP3, thereby maintaining the Th17/Treg balance. Notably, ROC analysis showed that the expression level of circETS1 in PBMCs had an area under the curve of 0.873 (95% confidence interval: 0.771-0.976; p < .001) for diagnosing SLE, with a sensitivity of 80.00% and a specificity of 89.29%. Finally, we found negative correlations between the level of circETS1 in PBMCs and disease severity (according to the Systemic Lupus Erythematosus Disease Activity Index) in patients with SLE (r = -0.7712, 95% CI: -0.8910 to -0.5509; p < .001). The imbalance in Th17/Treg cells in SLE may be attributed, in part, to the circETS1/miR-1205/FOXP3 pathway. CircETS1 has potential to serve as a valuable biomarker for the diagnosis and evaluation of SLE.

Identification, expression, and functional analysis of Hsf and Hsp20 gene families in Brachypodium distachyon under heat stress

Background

The heat shock factor (Hsf) and small heat shock protein (sHsp, also called Hsp20) complex has been identified as a primary component in the protection of plant cells from ubiquitous stresses, particularly heat stress. Our study aimed to characterize and analyze the Hsf and Hsp genes in Brachypodium distachyon, an annual temperate grass and model plant in cereal and grass studies.

Results

We identified 24 Hsf and 18 Hsp20 genes in B. distachyon and explored their evolution in gene organization, sequence features, chromosomal localization, and gene duplication. Our phylogenetic analysis showed that BdHsfs could be divided into three categories and BdHsp20s into ten subfamilies. Further analysis showed that the 3’UTR length of BdHsp20 genes had a negative relationship with their expression under heat stress. Expression analyses indicated that BdHsp20s and BdHsfs were strongly and rapidly induced by high-temperature treatment. Additionally, we constructed a complex regulatory network based on their expression patterns under heat stress. Morphological analysis suggested that the overexpression of five BdHsp20 genes enhanced the seed germination rate and decreased cell death under high temperatures.

Conclusion

Ultimately, our study provided important evolutionary and functional characterizations for future research on the regulatory mechanisms of BdHsp20s and BdHsfs in herbaceous plants under environmental stress.

Interaction of miR-181b and IFNA1 Polymorphisms on the Risk of Systemic Lupus Erythematosus

Introduction

A previous work has discovered that chromosome 1q32 locus linked to the risk of systemic lupus erythematosus (SLE) and miR-181b located on the susceptibility site with downregulation inversely correlating to its target molecular interferon alpha 1 (IFNA1). The purpose of this study was to investigate the association of miR-181b and IFNA1 polymorphisms with IS risk.

Methods

The miR-181b rs322931, IFNA1 rs1332190, and rs10811543 were genotyped using a Multiplex SNaPshot assay. miR-181b expression levels in plasma of SLE patients and controls were analyzed using quantitative PCR.

Results

The rs322931 CT, CT/TT, and T allele exerted an increased trend of SLE risk (CT vs. CC: adjusted OR = 1.71, 95% CI 1.16-2.50, P = 0.01; CT/TT vs. CC: adjusted OR = 1.45, 95% CI 1.08-1.95, P = 0.01; T vs. C: adjusted OR = 1.38, 95% CI 1.07-1.79, P = 0.01). Combined genotypes of the rs322931 CT/TT+rs1332190 TT and the rs322931 CC+rs10811543 AG/AA also revealed an increased risk of SLE. Gene-gene interaction analysis showed that a three-locus model consisting of rs322931, rs1332190, and rs10811543 attributed an increased risk of SLE. Further genotype-phenotype analysis revealed that rs322931 CT/TT carriers displayed lower levels of miR-181b.

Conclusions

These findings indicate that the miR-181b rs322931 may be singly and jointly responsible for the etiology of SLE by altering miR-181b expression.