Meta-analysis of TNF-α promoter − 238A/G polymorphism and SLE susceptibility

The Association of Serum TNF-α Levels and Blood Multi-Elements Modified by TNF-α Gene Polymorphisms in Metal Industrial Workers

Health of the metal industrial workers should be a noteworthy issue due to the hazard of chronic exposure to metals or toxic elements. The interactions among multiple elements are sophisticated and may differ from person to person. Tumor necrosis factor-α (TNF-α) gene polymorphisms were supposed to be involved with the interactions because TNF-α plays an important role in inflammation, a mechanism by which toxic elements cause threats to human health. This research aimed to analyze the influence of TNF-α gene polymorphisms and multi-elements on serum TNF-α level. Blood multi-elements concentrations (lead, cadmium, arsenic, selenium, cobalt, copper, and zinc), serum TNF-α level, and TNF-α single nucleotide polymorphisms (SNPs), including −238G > A (rs361525), −308G > A (rs1800629), −857C > T (rs1799724), −863C > A (rs1800630), and −1031T > C (rs1799964), were measured in 462 metal industrial workers. We applied mixed-effect models to analyze the interactions among multi-elements and TNF-α SNPs. Blood concentration of all elements were positively associated with serum TNF-α level, and the effects may be modified by TNF-α gene polymorphisms. Our study revealed that TNF-α −308A/A and −1031C/C may be susceptible genotypes, and thus we suggest that those workers should take preventive measures against metal toxicity.

Association of polymorphic variants of PTPN22, TNF and VDR systems in children with lupus nephritis: a study in trios of Colombian families

Introducción. El lupus eritematoso sistémico es una enfermedad autoinmune cuya gravedad varía según la raza, género y edad de aparición. Esta disparidad también se observa en los marcadores genéticos asociados con la enfermedad presentes en los genes PTPN22, VDR y TNF. La estratificación genética que presentan las diferentes poblaciones en el mundo puede estar influyendo dicha variabilidad.Objetivo. Analizar la asociación y heredabilidad de variantes genéticas de los genes PTPN22, VDR y TNF con nefritis lúpica pediátrica (NLp) en familias colombianas.Materiales y métodos. Se realizó un estudio basado en familias con 46 tríos (caso/padre y madre). Se genotipificaron las variantes rs2476601 de PTPN22; rs361525 y rs1800629 de TNF; TaqI [rs731236], ApaI [rs7975232], BsmI [rs1544410] y FokI [rs2228570] de VDR mediante qPCR. Se estimó el efecto de la sobretransmisión del alelo de riesgo de padres a hijos y el desequilibrio de ligamiento de los loci VDR y TNF.Resultados. Se observó que el alelo A de rs2476601 en PTPN22 se distribuyó en el 8,69 % [n=16] de los padres mientras que en los casos es de 19,5 % [n=18] al igual que es sobretransmitido de padres a hijos 17 veces más con relación al alelo G (p=0,028). Los polimorfismos de TNF y VDR no se mostraron en desequilibrio de transmisión. Las variantes TaqI, ApaI y BsmI del VDR se mostraron en desequilibrio de ligamiento.Conclusión. Estos hallazgos muestran una asociación del polimorfismo rs2476601 de PTPN22 con NLp debido a su sobretransmisión en el grupo de familias estudiadas.

A TNF variant that associates with susceptibility to musculoskeletal disease modulates thyroid hormone receptor binding to control promoter activation

Tumor necrosis factor (TNF) is a powerful pro-inflammatory cytokine and immuno-regulatory molecule, and modulates susceptibility to musculoskeletal diseases. Several meta-analyses and replicated association studies have implicated the minor 'A' variant within the TNF promoter single nucleotide polymorphism (SNP) rs361525 (-238A/G) as a risk allele in joint related disorders, including psoriatic and juvenile idiopathic arthritis, and osteolysis after joint arthroplasty. Here we characterized the effect of this variant on TNF promoter function. A transcriptional reporter, encoding the -238A variant of the TNF promoter, resulted in 2.2 to 2.8 times greater transcriptional activation versus the 'G' variant in murine macrophages when stimulated with pro-inflammatory stimuli. Bioinformatic analysis predicted a putative binding site for thyroid hormone receptor (TR) for the -238A but not the -238G allele. Overexpression of TR-α induced promoter expression 1.8-fold in the presence of the 'A' allele only. TR-α expression both potentiated and sensitized the -238A response to LPS or a titanium particulate stimulus, whilst siRNA knockdown of either THRA or THRB impaired transcriptional activation for the -238A variant only. This effect was independent of receptor-ligand binding of triiodothyronine. Immunohistochemical analysis of osteolysis interface membranes from patients undergoing revision surgery confirmed expression of TR-α within osteoclast nuclei at the resorption surface. The 'A' allele at rs361525 confers increased transcriptional activation of the TNF promoter and influences susceptibility to several arthritic conditions. This effect is modulated, at least in part, by binding of TR, which both sensitizes and potentiates transcriptional activation of the 'A' variant independent of its endogenous ligand.

Identification of MFG-E8 as a novel therapeutic target for diseases

INTRODUCTION

Milk fat globule-epidermal growth factor-factor 8 (MFG-E8), a peripheral membrane glycoprotein has been widely studied in recent years due to its omnipresent locations, express and multiple functions. Traditionally, MFG-E8 was identified as an outstanding factor for phagocytosis of apoptotic cells and a significant factor in immune systems. Recent studies with some new findings have shed an interesting light on the old peripheral membrane glycoprotein in various diseases.

AREAS COVERED

In inflammatory and the systemic lupus erythematosus-type autoimmune disease, age-related diseases and tumors, MFG-E8 plays a multifunctional role in attenuating inflammation and improving prognosis, healing wound and remodeling arterial and enhancing tumorigenicity and cancer metastasis. This review provides a comprehensive view on the latest advances in the field. The summarized knowledge will help to explore the potential therapeutic roles of MFG-E8 and to design MFG-E8-based strategies for the treatment of these diseases.

EXPERT OPINION

Though the exact roles of MFG-E8 have not been fully elucidated in diseases. MFG-E8 may serve as a promising therapeutic strategy.

GM-CSF alters dendritic cells in autoimmune diseases

Autoimmune diseases arise from an inappropriate immune response against self components, including macromolecules, cells, tissues, organs etc. They are often triggered or accompanied by inflammation, during which the levels of granulocyte macrophage colony-stimulating factor (GM-CSF) are elevated. GM-CSF is an inflammatory cytokine that has profound impact on the differentiation of immune system cells of myeloid lineage, especially dendritic cells (DCs) that play critical roles in immune initiation and tolerance, and is involved in the pathogenesis of autoimmune diseases. Although GM-CSF was discovered decades ago, recent studies with some new findings have shed an interesting light on the old hematopoietic growth factor. In the inflammatory autoimmune diseases, GM-CSF redirects the normal developmental pathway of DCs, conditions their antigen presentation capacities and endows them with unique cytokine signatures to affect autoimmune responses. Here we review the latest advances in the field, with the aim of demonstrating the effects of GM-CSF on DCs and their influences on autoimmune diseases. The summarized knowledge will help to design DC-based strategies for the treatment of autoimmune diseases.

Association of Fas gene polymorphisms with systemic lupus erythematosus: a meta-analysis

The Fas gene polymorphisms -670A/G (rs1800682) and -1377G/A (rs2234767) have been shown to be associated with systemic lupus erythematosus (SLE), but findings are not consistent. To clarify this point, a meta-analysis was performed. We searched PubMed, CNKI, CBM and Wanfang database. Meta-odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were used to combine the data by fixed/random effects models based on heterogeneity test. The statistical analyses were conducted using Stata software. A total of seven studies involving 759 cases and 820 controls were considered in this study and ethnicity-specific meta-analysis was performed on Caucasian and Asian population. In overall population, meta-analysis revealed a trend toward to an association between SLE and Fas -670 A allele (OR = 1.310, 95 %CI = 1.028 ~ 1.670, P = 0.029). Similar results were detected in recessive model (OR = 1.626, 95 %CI = 1.104 ~ 2.395, P = 0.014) and in homozygous genotypic contrast (OR = 1.728, 95 %CI = 1.049 ~ 2.848, P = 0.032). Stratification by ethnicity indicated a significant association between SLE and the Fas -670A/G polymorphism in Asian population when allelic contrast (OR = 1.331, 95 %CI = 1.066 ~ 1.662, P = 0.011), homozygous genotypic contrast (OR = 1.848, 95 %CI = 1.164 ~ 2.932, P = 0.009) and dominant model were performed (OR = 1.542, 95 %CI = 1.045 ~ 2.275, P = 0.029). Meta-analysis of the Fas -1377G/A polymorphism indicated a significant association between SLE and the G allele in overall population (OR = 1.277, 95 %CI = 1.004 ~ 1.624, P = 0.046). The results from this meta-analysis provide evidence for the association between the Fas -670A/G and -1377G/A polymorphism and the risk of SLE. However, further studies are needed to draw a definitive conclusion.

Autoimmunity in 2010

There is now growing evidence that autoimmunity is the common trait connecting multiple clinical phenotypes albeit differences in tissue specificity, pathogenetic mechanisms, and therapeutic approaches cannot be overlooked. Over the past years we witnessed a constant growth of the number of publications related to autoimmune diseases in peer-reviewed journals of the immunology area. Original data referred to factors from common injury pathways (i.e. T helper 17 cells, serum autoantibodies, or vitamin D) and specific diseases such as multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis. As an example, the issue of a latitudinal gradient in the prevalence and incidence rates has been proposed for all autoimmune diseases and was recently coined as geoepidemiology to suggest new environmental triggers for tolerance breakdown. The present article is aimed at reviewing the articles that were published over the past year in the major autoimmunity and immunology journals.

Abnormal production of pro- and anti-inflammatory cytokines by lupus monocytes in response to apoptotic cells

Monocytes are a key component of the innate immune system involved in the regulation of the adaptive immune response. Previous studies have focused on apoptotic cell clearance abnormalities in systemic lupus erythematosus (SLE) monocytes. However, whether SLE monocytes might express unique patterns of cytokine secretion in response to apoptotic cells is still unknown. Here, we used monocytes from healthy controls and SLE patients to evaluate the production of TNF-α and TGF-β in response to apoptotic cells. Upon recognition of apoptotic material, monocytes from healthy controls showed prominent TGF-β secretion (mean ± SD: 824.6±144.3 pg/ml) and minimal TNF-α production (mean ± SD: 32.6±2.1 pg/ml). In contrast, monocytes from SLE patients had prominent TNF-α production (mean ± SD: 302.2±337.5 pg/ml) and diminished TGF-β secretion (mean ± SD: 685.9±615.9 pg/ml), a difference that was statistically significant compared to normal monocytes (p≤10(-6) for TNF-α secretion, and p = 0.0031 for TGF-β, respectively). Interestingly, the unique cytokine response by SLE monocytes was independent of their phagocytic clearance efficiency, opsonizing autoantibodies and disease activity. We further showed that nucleic acids from apoptotic cells play important role in the induction of TNF-α by lupus monocytes. Together, these observations suggest that, in addition to potential clearance defects, monocytes from SLE patients have an abnormal balance in the secretion of anti- and pro-inflammatory cytokines in response to apoptotic cells. Since the abnormal cytokine response to apoptotic material in SLE is not related to disease activity and opsonizing autoantibodies, it is possible that this response might be an intrinsic property of lupus monocytes. The studies focus attention on toll-like receptors (TLRs) and their downstream pathways as mediators of this response.