Varying levels of X chromosome coalescence in female somatic cells alters the balance of X-linked dosage compensation and is implicated in female-dominant systemic lupus erythematosus

Effect of LncRNA XIST on Immune Cells of Primary Biliary Cholangitis

Objective

Primary biliary cholangitis (PBC) is an autoimmune disease with significant gender difference. X chromosome inactivation (XCI) plays important roles in susceptibility to diseases between genders. This work focuses on the differences of LncRNA XIST in several defined immune cells populations as well as its effects on naive CD4+ T cells proliferation and differentiation in patients with PBC.

Methods

NKs, B cells, CD4+ T, and CD8+ T cells were separated by MicroBeads from peripheral blood mononuclear cells (PBMCs) of PBC patients and healthy control (HC). The expression levels of LncRNA XIST in these immune cells were quantified by qRT-PCR and their subcellular localized analyzed by FISH. Lentivirus were used to interfere the expression of LncRNA XIST, and CCK8 was used to detect the proliferation of naive CD4+ T cells in PBC patients. Finally, naive CD4+ T cells were co-cultured with the bile duct epithelial cells (BECs), and the effects of LncRNA XIST on the typing of naive CD4+ T cells and related cytokines were determined by qRT-PCR and ELISA.

Results

The expression levels of LncRNA XIST in NKs and CD4+ T cells in PBC patients were significantly higher than those in HC, and were primarily located at the nucleus. LncRNA XIST could promote the proliferation of naive CD4+ T cells. When naive CD4+ T cells were co-cultured with BECs, the expressions of IFN-γ, IL-17, T-bet and RORγt in naive CD4+ T cells were decreased.

Conclusion

LncRNA XIST was associated with lymphocyte abnormalities in patients with PBC. The high expression of LncRNA XIST could stimulate proliferation and differentiation of naive CD4+ T cells, which might account for the high occurrence of PBC in female.

Involvement of N6-methyladenosine modifications of long noncoding RNAs in systemic lupus erythematosus

BACKGROUND

LncRNAs are potential biomarkers for SLE, but the epigenetic regulatory mechanisms of N6-methyladenosine (m6A) modification in SLE remain largely unclear.

METHODS

In this study, we established m6A modification profile and investigated the potential roles of m6A-related lncRNAs in SLE. The m6A modification profile of SLE was established using MeRIP-seq. Four potential m6A related-lncRNAs (linc02446, linc01410, Xist, and PSMB8-AS1) were selected for validation using qRT-PCR, and their expression and association with clinical characteristics with SLE were evaluated.

RESULTS

Overall, m6A level was lower in patients with SLE than in controls. Compared with controls, the expression of the two m6A related-lncRNAs (Xist and PSMB8-AS1) was downregulated in patients with SLE (all P < 0.05); the linc02446 was up-regulated in PBMCs of patients with SLE (Z=-2.738, P = 0.006), while it was not differentially expressed in T cells (Z=-0.387, P = 0.699). No significant alteration in linc01410 expression was observed in patients (Z=-0.940, P = 0.347). The lower expression levels of Xist and PSMB8-AS1 were associated with many clinical manifestations in patients with SLE (all P < 0.05). Additionally, mRNAs co-expressed with m6A related-lncRNAs (Xist, linc02446, and PSMB8-AS1) also participated in SLE.

CONCLUSION

These results suggest that m6A methylation and m6A related-lncRNAs might be involved in the pathogenesis of SLE. Thus, our findings provide some clues on the potential function of lncRNAs that m6A modification may target in novel therapeutic or diagnostic strategies for SLE.

Evolving Views of Long Noncoding RNAs and Epigenomic Control of Lymphocyte State and Memory

Not simply an attribute of the adaptive immune system, immunological memory can be viewed on multiple levels. Accordingly, the molecular basis of memory comprises multiple mechanisms. The advent of new sequencing technologies has greatly enhanced the understanding of gene regulation and lymphocyte specification, and improved measurement of chromatin states affords new insights into the epigenomic and transcriptomic programs that underlie memory. Beyond canonical genes, the involvement of long noncoding RNAs (lncRNAs) is becoming increasingly apparent, and it appears that there are more than two to three times as many lncRNAs as protein-coding genes. lncRNAs can directly interact with DNA, RNA, and proteins, and a single lncRNA can contain multiple modular domains and thus interact with different classes of molecules. Yet, most lncRNAs have not been tested for function, and even fewer knockout mice have been generated. It is therefore timely to consider new potential mechanisms that may contribute to immune memory.

The X Files: "The Mystery of X Chromosome Instability in Alzheimer's Disease"

Alzheimer's disease (AD) is a neurodegenerative disease that affects millions of individuals worldwide and can occur relatively early or later in life. It is well known that genetic components, such as the amyloid precursor protein gene on chromosome 21, are fundamental in early-onset AD (EOAD). To date, however, only the apolipoprotein E4 (ApoE4) gene has been proved to be a genetic risk factor for late-onset AD (LOAD). In recent years, despite the hypothesis that many additional unidentified genes are likely to play a role in AD development, it is surprising that additional gene polymorphisms associated with LOAD have failed to come to light. In this review, we examine the role of X chromosome epigenetics and, based upon GWAS studies, the PCDHX11 gene. Furthermore, we explore other genetic risk factors of AD that involve X-chromosome epigenetics.