Polymorphisms in STK17A gene are associated with systemic lupus erythematosus and its clinical manifestations

New insights into the characteristics of DRAK2 and its role in apoptosis: From molecular mechanisms to clinically applied potential

As a member of the death-associated protein kinase (DAPK) family, DAP kinase-associated apoptosis-inducing kinase 2 (DRAK2) performs apoptosis-related functions. Compelling evidence suggests that DRAK2 is involved in regulating the activation of T lymphocytes as well as pancreatic β-cell apoptosis in type I diabetes. In addition, DRAK2 has been shown to be involved in the development of related tumor and non-tumor diseases through a variety of mechanisms, including exacerbation of alcoholic fatty liver disease (NAFLD) through SRSF6-associated RNA selective splicing mechanism, regulation of chronic lymphocytic leukemia and acute myeloid leukemia, and progression of colorectal cancer. This review focuses on the structure, function, and upstream pathways of DRAK2 and discusses the potential and challenges associated with the clinical application of DRAK2-based small-molecule inhibitors, with the aim of advancing DRAK2 research.

Inhibition of miR-182-5p attenuates ROS and protects against myocardial ischemia-reperfusion injury by targeting STK17A

Reperfusion therapy for acute myocardial infarction inevitably leads to ischemia-reperfusion (I/R) injury. A number of miRNAs are reported to be involved in I/R injury. This study aims to investigate the role and underlying mechanism of miR-182-5p in I/R injury. An in vivo model of I/R-induced rat myocardial injury and an in vitro model of H/R H9c2 cells were established to investigate the role and mechanism of miR-182-5p in I/R injury. The myocardial infarct size was determined by TTC staining. The serum CK-MB level was determined by ELISA kit. The miR-182-5p inhibitors or mimics were used to down-regulate or up-regulate its expression. The apoptosis and ROS were detected by flow cytometry. The expression of the proteins was detected by western blot. The binding of STK17A and miR-182-5p was validated by dual-luciferase reporter assay. The miR-182-5p was confirmed to be highly expressed in I/R injury rats and H/R H9c2 cells. Inhibition of miR-182-5p significantly reduced the infarct size and decreased the serum CK-MB level of I/R rats, and significantly reduced the ROS level but increased the level of MnSOD and catalase. While, an opposite effect was observed in the miR-182-5p mimics group. Furthermore, our results suggested that miR-182-5p targeted STK17A, and TK17A knockdown significantly increased the apoptotic rate and ROS level. The inhibitory effect of miR-182-5p inhibitors on apoptotic rate, ROS, MnSOD, and catalase levels were abrogated by siSTK17A. These results indicate that miR-182-5p regulates the apoptosis and ROS and protects against myocardial I/R injury by targeting STK17A.

Whole-genome sequencing analysis of semi-supercentenarians

Extreme longevity is the paradigm of healthy aging as individuals who reached the extreme decades of human life avoided or largely postponed all major age-related diseases. In this study, we sequenced at high coverage (90X) the whole genome of 81 semi-supercentenarians and supercentenarians [105+/110+] (mean age: 106.6 ± 1.6) and of 36 healthy unrelated geographically matched controls (mean age 68.0 ± 5.9) recruited in Italy. The results showed that 105+/110+ are characterized by a peculiar genetic background associated with efficient DNA repair mechanisms, as evidenced by both germline data (common and rare variants) and somatic mutations patterns (lower mutation load if compared to younger healthy controls). Results were replicated in a second independent cohort of 333 Italian centenarians and 358 geographically matched controls. The genetics of 105+/110+ identified DNA repair and clonal haematopoiesis as crucial players for healthy aging and for the protection from cardiovascular events.

Cutaneous lupus erythematosus: new insights into pathogenesis and therapeutic strategies

Cutaneous lupus erythematosus (CLE) is an autoimmune disease that can present as an isolated skin disease or as a manifestation within the spectrum of systemic lupus erythematosus. The clinical spectrum of CLE is broad, ranging from isolated discoid plaques to widespread skin lesions. Histologically, skin lesions present as interface dermatitis (inflammation of the skin mediated by anti-epidermal responses), which is orchestrated by type I and type III interferon-regulated cytokines and chemokines. Both innate and adaptive immune pathways are strongly activated in the formation of skin lesions owing to continuous re-activation of innate pathways via pattern recognition receptors (PRRs). These insights into the molecular pathogenesis of skin lesions in CLE have improved our understanding of the mechanisms underlying established therapies and have triggered the development of targeted treatment strategies that focus on immune cells (for example, B cells, T cells or plasmacytoid dendritic cells), as well as immune response pathways (for example, PRR signalling, Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signalling and nuclear factor-κB signalling) and their cytokines and chemokines (for example, type I interferons, CXC-chemokine ligand 10 (CXCL10), IL-6 and IL-12).

Integrated analysis of lncRNA, miRNA and mRNA expression profiling in patients with systemic lupus erythematosus

INTRODUCTION

A great deal of research has reported dysregulated expression of genes in systemic lupus erythematosus (SLE). This study aimed to analyze the lncRNA, miRNA and mRNA expression profile in SLE.

MATERIAL AND METHODS

RNA sequencing (RNA-seq) was used to detect the dysregulated RNAs in SLE. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis were used to explore the function of these differentially expressed RNAs.

RESULTS

2,353 lncRNAs, 827 mRNAs and 24 miRNAs were shown to be differentially expressed. GO analyses demonstrated that differentially expressed RNAs were enriched in a variety of molecular functions and biological processes including ribonucleotide, protein serine/threonine kinase activity function, regulation of B cell differentiation and others. KEGG pathway analyses revealed that differentially expressed mRNAs and lncRNAs were both enriched in FcγR-mediated phagocytosis, glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate and glyoxylate and dicarboxylate metabolism pathways. The up-regulated miRNAs target genes were mainly enriched in the nuclear factor-κB (NF-κB) signaling pathway. The down-regulated miRNAs target genes were significantly enriched in metabolism of xenobiotics by cytochrome P450, bile secretion and terpenoid backbone biosynthesis pathways.

CONCLUSIONS

The current study reveals a comprehensive expression profile of lncRNAs, miRNAs and mRNAs and implies potential regulatory functions of these RNAs which are involved in the pathogenesis of SLE.

Immunogenetics of cutaneous lupus erythematosus

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is the prototypic autoimmune condition, often affecting multiple organ systems, including the skin. Cutaneous lupus erythematosus (CLE) is distinct from SLE and may be skin limited or associated with systemic disease. Histopathologically, the hallmark of lupus-specific manifestations of SLE and CLE is an interface dermatitis. The cause of SLE and CLE is likely multifactorial and may include shared genetic factors. In this review, we will discuss the genetic findings related to the cutaneous manifestations of SLE and isolated CLE, with a particular focus on the lupus-specific CLE subtypes.

RECENT FINDINGS

Several major histocompatibility complex and nonmajor histocompatibility complex genetic polymorphisms have been identified which may contribute to the cutaneous manifestations of SLE and to CLE. Most of these genetic variants are associated with mechanisms attributed to the pathogenesis of SLE, including pathways involved in interferon and vitamin D regulation and ultraviolet light exposure. Although there is overlap between the genetic factors associated with SLE and CLE, there appear to be unique genetic factors specific for CLE.

SUMMARY

Improved understanding of the genetics of CLE may lead to the creation of targeted therapies, improving outcomes for patients with this challenging dermatologic condition.

DNA-damaging autoantibodies and cancer: the lupus butterfly theory

Autoantibodies reactive against host DNA are detectable in the circulation of most people with systemic lupus erythematosus (SLE). The long-held view that antibodies cannot penetrate live cells has been disproved. A subset of lupus autoantibodies penetrate cells, translocate to nuclei, and inhibit DNA repair or directly damages DNA. The result of these effects depends on the microenvironment and genetic traits of the cell. Some DNA-damaging antibodies alone have little impact on normal cells, but in the presence of other conditions, such as pre-existing DNA-repair defects, can become highly toxic. These findings raise new questions about autoimmunity and DNA damage, and reveal opportunities for new targeted therapies against malignancies particularly vulnerable to DNA damage. In this Perspectives article, we review the known associations between SLE, DNA damage and cancer, and propose a theory for the effects of DNA-damaging autoantibodies on SLE pathophysiology and cancer risk.

Genome-wide association analysis identifies genetic variations in subjects with myalgic encephalomyelitis/chronic fatigue syndrome

Myalgic encephalomyelitis, also known as chronic fatigue syndrome or ME/CFS, is a multifactorial and debilitating disease that has an impact on over 4 million people in the United States alone. The pathogenesis of ME/CFS remains largely unknown; however, a genetic predisposition has been suggested. In the present study, we used a DNA single-nucleotide polymorphism (SNP) chip representing over 906,600 known SNPs to analyze DNA from ME/CFS subjects and healthy controls. To the best of our knowledge, this study represents the most comprehensive genome-wide association study (GWAS) of an ME/CFS cohort conducted to date. Here 442 SNPs were identified as candidates for association with ME/CFS (adjusted P-value<0.05). Whereas the majority of these SNPs are represented in non-coding regions of the genome, 12 SNPs were identified in the coding region of their respective gene. Among these, two candidate SNPs resulted in missense substitutions, one in a pattern recognition receptor and the other in an uncharacterized coiled-coil domain-containing protein. We also identified five SNPs that cluster in the non-coding regions of T-cell receptor loci. Further examination of these polymorphisms may help identify contributing factors to the pathophysiology of ME/CFS, as well as categorize potential targets for medical intervention strategies.

Genetic Factors in Systemic Lupus Erythematosus: Contribution to Disease Phenotype

Genetic factors exert an important role in determining Systemic Lupus Erythematosus (SLE) susceptibility, interplaying with environmental factors. Several genetic studies in various SLE populations have identified numerous susceptibility loci. From a clinical point of view, SLE is characterized by a great heterogeneity in terms of clinical and laboratory manifestations. As widely demonstrated, specific laboratory features are associated with clinical disease subset, with different severity degree. Similarly, in the last years, an association between specific phenotypes and genetic variants has been identified, allowing the possibility to elucidate different mechanisms and pathways accountable for disease manifestations. However, except for Lupus Nephritis (LN), no studies have been designed to identify the genetic variants associated with the development of different phenotypes. In this review, we will report data currently known about this specific association.

Genetic Variants of IκB Kinase β (IKBKB) and Polymerase β (POLB) Were Not Associated with Systemic Lupus Erythematosus Risk in a Chinese Han Population

A previous large-scale replication study validation of a genome wide association study (GWAS) identified IκB kinase β (IKBKB) single nucleotide polymorphisms (SNPs) as a risk factor associated with systemic lupus erythematosus (SLE) in a Chinese Han population. IKBKB SNPs were associated with polymerase β (POLB) SNPs and reduced POLB expression, and this was proposed to be an underlying cause of human SLE development. In the current case-control study, we evaluated IKBKB (rs12676482 and rs2272733) and POLB (rs3136717 and rs3136744) SNPs in 946 SLE patients and 961 healthy controls. We investigated the possible association of these four SNPs with SLE in a Chinese Han population using the polymerase chain reaction-ligation detection reaction (PCR-LDR) technique. The differences in the frequencies of the four SNP alleles and the genotypes and haplotypes of the POLB polymorphisms were statistically insignificant when the SLE patients were compared with the controls in the Chinese Han population enrolled in this study (all, p ˃ 0.05). Furthermore, no associations were detected using different genetic models (additive, dominant, and recessive; all, p ˃ 0.05). Our findings indicate that the IKBKB (rs12676482 and rs2272733) and POLB (rs3136717, rs3136744) SNPs confer no genetic predisposition to SLE risk in this Chinese Han population.

CXCL13 as a new biomarker of systemic lupus erythematosus and lupus nephritis - from bench to bedside?

Different studies over the last decade have linked the B cell-attracting chemokine CXC ligand 13 (CXCL13) to the autoimmune disease systemic lupus erythematosus (SLE). A pathogenetic role of this chemokine for disease manifestation in SLE was described initially in mouse models for SLE. Mechanisms of CXCL13 actions were also identified in SLE patients. Moreover, various clinical studies have identified CXCL13 serum levels as a useful biomarker in patients with SLE of different ethnicities for disease activity. In addition, CXCL13 seems to be a promising marker for the diagnosis of lupus nephritis, one of the most severe complications of SLE. However, its exact place within the mechanisms that lead to SLE remains to be defined. Further research is needed to resolve more details of the pathomechanism and the signalling pathway of CXCL13 in SLE. Blocking CXCL13 or the signal pathways of CXCL13 is seen as a promising therapeutic approach for SLE and will be addressed in the near future. This review summarizes all papers that linked CXCL13 to SLE and highlights its importance in the pathogenesis and diagnosis of SLE.

Upregulated PD-1 Expression Is Associated with the Development of Systemic Lupus Erythematosus, but Not the PD-1.1 Allele of the PDCD1 Gene

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with complicated genetic inheritance. Programmed death 1 (PD-1), a negative T cell regulator to maintain peripheral tolerance, induces negative signals to T cells during interaction with its ligands and is therefore a candidate gene in the development of SLE. In order to examine whether expression levels of PD-1 contribute to the pathogenesis of SLE, 30 patients with SLE and 30 controls were recruited and their PD-1 expression levels in peripheral blood mononuclear cells (PBMCs) were measured via flow cytometry and quantitative real-time-reverse transcription polymerase chain reaction (RT-PCR). Also, whether PD-1 expression levels are associated with the variant of the SNP rs36084323 and the SLE Disease Activity Index (SLEDAI) was studied in this work. The PD-1 expression levels of SLE patients were significantly increased compared with those of the healthy controls. The upregulated PD-1 expression levels in SLE patients were greatly associated with SLEDAI scores. No significant difference was found between PD-1 expression levels and SNP rs36084323. The results suggest that increased expression of PD-1 may correlate with the pathogenesis of SLE, upregulated PD-1 expression may be a biomarker for SLE diagnosis, and PD-1 inhibitor may be useful to SLE treatment.

Systemic Lupus Erythematosus: Old and New Susceptibility Genes versus Clinical Manifestations

Systemic Lupus Erythematosus (SLE) is one of the most relevant world-wide autoimmune disorders. The formation of autoantibodies and the deposition of antibody-containing immune complexes in blood vessels throughout the body is the main pathogenic mechanism of SLE leading to heterogeneous clinical manifestations and target tissue damage. The complexity of etiology and pathogenesis in SLE, enclosing genetic and environmental factors, apparently is one of the greatest challenges for both researchers and clinicians. Strong indications for a genetic background in SLE come from studies in families as well as in monozygotic and dizygotic twins, discovering several SLE-associated loci and genes (e.g. IRF5, PTPN22, CTLA4, STAT4 and BANK1). As SLE has a complex genetic background, none of these genes is likely to be entirely responsible for triggering autoimmune response in SLE even if they disclosure a potentially novel molecular mechanisms in the pathogenesis' disease. The clinical manifestations and disease severity varies greatly among patients, thus several studies try to associate clinical heterogeneity and prognosis with specific genetic polymorphisms in SLE associated genes. The continue effort to describe new predisposing or modulating genes in SLE is justified by the limited knowledge about the pathogenesis, assorted clinical manifestation and the possible prevention strategies. In this review we describe newly discovered, as well as the most studied genes associated to SLE susceptibility, and relate them to clinical manifestations of the disease.

Clinical and immunological pattern of systemic lupus erythematosus in men in a cohort of 2355 patients

AIM

To investigate the impact of gender on expression of systemic lupus erythematosus (SLE) in a cohort of 2355 SLE patients as one of the largest series of cases among the present reports.

METHOD

In this retrospective study we used medical records of all patients (239 male and 2116 female) of the SLE registry of Rheumatology Research Center (RRC), Tehran University of Medical science (TUMS), Iran. Both clinical and paraclinical manifestations of SLE patients have been registered in this database since 1976 and updated during their follow-up. Chi-square test was used to compare the clinical and paraclinical manifestations in men and women at disease onset and during the disease course. We used logistic regression to compute odds ratios with 95% confidence intervals. A P-value < 0.05 was considered as statistically significant.

RESULTS

Mean age at disease onset was 25 ± 11.8 and 24.5 ± 10.3 years in men and women, respectively (P = 0.48). Comparison of clinical and immunological manifestations showed that male patients had a higher prevalence of mucocutaneous (43.5% vs. 33.7%, P = 0.005) and a lower prevalence of musculoskeletal symptoms (44% vs. 54.7%, P = 0.003) as the initial manifestation. During the disease course, discoid rash (25.9% vs. 13%, P = 0.000) and type IV lupus nephritis (23.4% vs. 18.1%, P = 0.03) were significantly more common, whereas arthritis (61.1% vs. 71.7%, P = 0.01) and leukopenia (28.5% vs. 35.8%, P = 0.024) were significantly less common in men.

CONCLUSION

This study reveals gender influence on some manifestations of SLE. Considering sex differences is recommended in diagnostic and therapeutic features of the disease.

LIG4 and RAD52 DNA repair genes polymorphisms and systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder with a strong genetic background. Nevertheless, SLE might also be triggered due to environmental factors, such as UV light exposure. DNA double strand breaks (DSBs) may be induced secondarily by UV radiation, increasing DNA immunogenicity and in SLE patients DNA repair is diminished, allowing the accumulation of DSBs and genomic instability. LIG4 and RAD52 genes play important roles in DNA repair mechanisms and a recent microarray analysis showed their differential expression in active SLE patients. In this study we investigated a potential association between LIG4 and RAD52 single nucleotide polymorphisms (SNPs) and SLE predisposition in a Southeast Brazilian population. We assessed four Tag SNPs in LIG4 and three in RAD52 gene region, encompassing most of the gene sequence, in 158 SLE patients and 212 healthy controls. We also performed SNPs analysis considering clinical manifestation, gender and ethnicity in SLE patients. Our data did not show association between LIG4 and RAD52 SNPs and SLE, its clinical manifestations or ethnicity in the tested population. The analysis regarding ethnicity and SLE clinical manifestations indicated Caucasian-derived patients as more susceptible to cutaneous and hematological alterations than the African-derived. To our knowledge, this is the first association study involving LIG4 and RAD52 genes and SLE predisposition.