Polymorphisms of BLK are associated with renal disorder in patients with systemic lupus erythematosus

B-Lymphoid Tyrosine Kinase Crosslinks Redox and Apoptosis Signaling Networks to Promote the Survival of Transplanted Bone Marrow Mesenchymal Stem Cells

Stress-induced apoptosis presents an obstacle to bone marrow mesenchymal stem cell (BMSC) transplantation to repair steroid-induced osteonecrosis of the femoral head (SONFH). Thus, appropriate intervention strategies should be explored to mitigate this. In our previous study, we discovered a new subgroup of BMSCs-the oxidative stress-resistant BMSCs (OSR-BMSCs)-which can survive the oxidative stress microenvironment in the osteonecrotic area, through a mechanism that currently remains unclear. In this study, we found that B-lymphoid tyrosine kinase (BLK) may be the crucial factor regulating the oxidative stress resistance of OSR-BMSCs, as it is highly expressed in these cells. Knockdown of BLK eliminated oxidative stress resistance, aggravated oxidative stress-induced apoptosis, reduced the survival of OSR-BMSCs in the oxidative stress microenvironment of the osteonecrotic area, and greatly weakened the transplantation efficacy of OSR-BMSCs for SONFH. By contrast, BLK was weakly expressed in oxidative stress-sensitive BMSCs (OSS-BMSCs). Overexpression of BLK in susceptible OSS-BMSCs allowed them to acquire oxidative stress resistance, inhibited oxidative stress-induced apoptosis, promoted their survival in the osteonecrotic area, and improved the transplantation efficacy of OSS-BMSCs for SONFH. Mechanistically, BLK concurrently activates redox and apoptotic signaling networks through its tyrosine kinase activity, which confers oxidative stress resistance to BMSCs and inhibits their stress-induced apoptosis of BMSCs. Herein, we report that OSR-BMSCs have intrinsic oxidative stress resistance that is conferred and mediated by BLK. This finding provides a potential new intervention strategy for improving the survival of transplanted BMSCs and the therapeutic efficacy of BMSC transplantation for SONFH.

SPAGRM: effectively controlling for sample relatedness in large-scale genome-wide association studies of longitudinal traits

Sample relatedness is a major confounder in genome-wide association studies (GWAS), potentially leading to inflated type I error rates if not appropriately controlled. A common strategy is to incorporate a random effect related to genetic relatedness matrix (GRM) into regression models. However, this approach is challenging for large-scale GWAS of complex traits, such as longitudinal traits. Here we propose a scalable and accurate analysis framework, SPAGRM, which controls for sample relatedness via a precise approximation of the joint distribution of genotypes. SPAGRM can utilize GRM-free models and thus is applicable to various trait types and statistical methods, including linear mixed models and generalized estimation equations for longitudinal traits. A hybrid strategy incorporating saddlepoint approximation greatly increases the accuracy to analyze low-frequency and rare genetic variants, especially in unbalanced phenotypic distributions. We also introduce SPAGRM(CCT) to aggregate the results following different models via Cauchy combination test. Extensive simulations and real data analyses demonstrated that SPAGRM maintains well-controlled type I error rates and SPAGRM(CCT) can serve as a broadly effective method. Applying SPAGRM to 79 longitudinal traits extracted from UK Biobank primary care data, we identified 7,463 genetic loci, making a pioneering attempt to conduct GWAS for these traits as longitudinal traits.

Exploring the contribution of genetics on the clinical manifestations of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by diverse clinical manifestations affecting multiple organs and systems. The understanding of genetic factors underlying the various manifestations of SLE has evolved considerably in recent years. This review provides an overview of the genetic implications in some of the most prevalent manifestations of SLE, including renal involvement, neuropsychiatric, cutaneous, constitutional, musculoskeletal, and cardiovascular manifestations. We discuss the current state of knowledge regarding the genetic basis of these manifestations, highlighting key genetic variants and pathways implicated in their pathogenesis. Additionally, we explore the clinical implications of genetic findings, including their potential role in risk stratification, prognosis, and personalized treatment approaches for patients with SLE. Through a comprehensive examination of the genetic landscape of SLE manifestations, this review aims to provide insights into the underlying mechanisms driving disease heterogeneity and inform future research directions in this field.

BLK polymorphisms and expression level in neuromyelitis optica spectrum disorder

Aim

This study aimed to determine the correlation between B‐lymphoid tyrosine kinase (BLK) polymorphism, mRNA gene expression of BLK, and NMOSD in a Chinese Han population.

Background

B‐lymphoid tyrosine kinase gene expressed mainly in B cells plays a key role in various autoimmune disorders. However, no studies have investigated the association of BLK polymorphisms with neuromyelitis optica spectrum disorder (NMOSD).

Methods

Han Chinese population of 310 subjects were recruited to analyze three single nucleotide polymorphisms (rs13277113, rs4840568, and rs2248932) under allele, genotype, and haplotype frequencies, followed by clinical characteristics stratified analysis. Real‐time PCR was used to analyze mRNA expression levels of BLK in the peripheral blood mononuclear cells of 64 subjects.

Results

Patients with NMOSD showed lower frequencies of the minor allele G of rs2248932 than healthy controls (odds ratio (OR) =0.57, 95% confidence intervals (CI) 0.39–0.83, p = 0.003). The association between minor allele G of rs2248932 and reduced NMOSD susceptibility was found by applying genetic models of inheritance (codominant, dominant, and recessive) and haplotypes analysis. Subsequently, by stratification analysis for AQP4‐positivity, the minor allele G frequencies of rs2248932 in AQP4‐positive subgroup were significantly lower than in the healthy controls (OR =0.46, 95% CI 0.30–0.72, p = 0.001). Notably, the genotype GG of rs2248932 was more frequent in AQP4‐negative subgroup (n = 14) than in AQP4‐positive subgroup (n = 93) (p = 0.003, OR =0.05, 95% CI =0.01–0.57). BLK mRNA expression levels in the NMOSD patients (n = 36) were lower than in healthy controls (n = 28) (p < 0.05). However, the acute non‐treatment (n = 7), who were untreated patients in the acute phase from the NMOSD group, showed BLK mRNA expression levels 1.8‐fold higher than healthy controls (n = 8) (p < 0.05).

Conclusion

This study evaluated that the minor allele G of rs2248932 in BLK is associated with reduced susceptibility to NMOSD and protected the risk of AQP4‐positive. BLK mRNA expression in NMOSD was lower as compared to healthy controls while significantly increased in acute‐untreated patients.