TASL

X chromosome inactivation can balance the effects of the two X chromosomes in females, and emerging evidence indicates that numerous genes on the inactivated X chromosome have the potential to evade inactivation. The mechanisms of escape include modification of DNA, RNA, histone, epitope, and various regulatory proteins, as well as the spatial structure of chromatin. The study of X chromosome inactivation escape has paved the way for investigating sex dimorphism in human diseases, particularly autoimmune diseases. It has been demonstrated that the presence of TLR7, CD40L, IRAK-1, CXCR3, and CXorf21 significantly contributes to the prevalence of SLE (systemic lupus erythematosus) in females. This article mainly reviews the molecular mechanisms underlying these genes that escape from X-chromosome inactivation and sexual dimorphism of systemic lupus erythematosus. Therefore, elucidating the molecular mechanisms underlying sexual dimorphism in SLE is not only crucial for diagnosing and treating the disease, but also holds theoretical significance in comprehensively understanding the development and regulatory mechanisms of the human immune system.

Systemic lupus erythematosus (SLE) is a common autoimmune disease that impacts various organs. Lupus nephritis (LN) significantly contributes to death in children with SLE. Toll-like receptor (TLR) adaptor interacting with SLC15A4 on the lysosome (TASL) acts as an innate immune adaptor for TLR and is implicated in the pathogenesis of SLE. A transcription factor known as signal transducer and activator of transcription 3 (STAT3), which is known to be linked to autoimmune diseases, is also involved in the development of SLE.

Bioinformatics and real-time quantitative PCR (qRT-PCR) was used to detect the expression of STAT3 and TASL in peripheral blood of SLE patients and their correlation. Bioinformatics analysis, qRT-PCR, luciferase assay and chromatin immunoprecipitation (ChIP) were used to verify the regulation of transcription factor STAT3 on TASL. The expression levels of STAT3, TASL and apoptosis-related genes in LPS-induced HK2 cells were detected by qRT-PCR and Western blot. TUNEL staining were used to detect the apoptosis of HK2 cells after LPS stimulation. ELISA and qRT-PCR were used to detect the levels of inflammatory cytokines in the cell culture supernatant. TASL knockdown in HK2 cells was used to detect the changes in apoptosis-related genes and inflammatory factors. The expression level of TASL in LPS-stimulated HK2 cells and its effect on cell apoptosis and inflammatory factors were observed by knocking down and overexpressing STAT3, respectively. It was also verified in a rescue experiment.

The expressions of STAT3 and TASL were higher in SLE than in healthy children, and the expression of STAT3 was positively correlated with TASL. Transcription factor STAT3 can directly and positively regulate the expression of TASL through the promoter region binding site. The expression of STAT3, TASL and inflammatory cytokines was elevated, and the change of apoptosis was up-regulated in LPS-stimulated HK2 cells. Inhibition of STAT3 alleviates LPS-stimulated apoptosis and inflammatory response in HK2 cells through transcriptional regulation of TASL.

These findings provide new insights into the transcriptional regulation of TASL and provide new evidence of a direct regulatory relationship between signaling nodes in the lupus signaling network.

MicroRNA482/2118 (miR482/2118) is a 22-nt miRNA superfamily, with conserved functions in disease resistance and plant development. It usually instigates the production of phased small interfering RNAs (phasiRNAs) from its targets to expand or reinforce its silencing effect. Using a new high-quality reference genome sequence and comprehensive small RNA profiling, we characterized a newly evolved regulatory pathway of miR482/2118 in litchi. In this pathway, miR482/2118 cleaved a novel noncoding trans-acting gene (LcTASL1) and triggered phasiRNAs to regulate the expression of gibberellin (GA) receptor gene GIBBERELLIN INSENSITIVE DWARF1 (GID1) in trans; another trans-acting gene LcTASL2, targeted by LcTASL1-derived phasiRNAs, produced phasiRNAs as well to target LcGID1 to reinforce the silencing effect of LcTASL1. We found this miR482/2118-TASL-GID1 pathway was likely involved in fruit development, especially the seed development in litchi. In vivo construction of the miR482a-TASL-GID1 pathway in Arabidopsis could lead to defects in flower and silique development, analogous to the phenotype of gid1 mutants. Finally, we found that a GA-responsive transcription factor, LcGAMYB33, could regulate LcMIR482/2118 as a feedback mechanism of the sRNA-silencing pathway. Our results deciphered a lineage-specifically evolved regulatory module of miR482/2118, demonstrating the high dynamics of miR482/2118 function in plants.