Faculty Bibliography

We targeted LYN, a src-tyosine kinase involved in B-cell activation, in case-control association studies using populations of European-American, African-American and Korean subjects. Our combined European-derived population, consisting of 2463 independent cases and 3131 unrelated controls, shows significant association with rs6983130 in a female-only analysis with 2254 cases and 2228 controls (P=1.1 x 10(-4), odds ratio (OR)=0.81 (95% confidence interval: 0.73-0.90)). This single nucleotide polymorphism (SNP) is located in the 5' untranslated region within the first intron near the transcription initiation site of LYN. In addition, SNPs upstream of the first exon also show weak and sporadic association in subsets of the total European-American population. Multivariate logistic regression analysis implicates rs6983130 as a protective factor for systemic lupus erythematosus (SLE) susceptibility when anti-dsDNA, anti-chromatin, anti-52 kDa Ro or anti-Sm autoantibody status were used as covariates. Subset analysis of the European-American female cases by American College of Rheumatology classification criteria shows a reduction in the risk of hematological disorder with rs6983130 compared with cases without hematological disorders (P=1.5 x 10(-3), OR=0.75 (95% CI: 0.62-0.89)). None of the 90 SNPs tested show significant association with SLE in the African American or Korean populations. These results support an association of LYN with European-derived individuals with SLE, especially within autoantibody or clinical subsets

Systemic lupus erythematosus (SLE) is an autoimmune disease with highly variable clinical presentation. Patients suffer from immunological abnormalities that target T-cell, B-cell and accessory cell functions. B cells are hyperactive in SLE patients. An adapter protein expressed in B cells called BANK1 (B-cell scaffold protein with ankyrin repeats) was reported in a previous study to be associated with SLE in a European population. The objective of this study was to assess the BANK1 genotype-phenotype association in an independent replication sample. We genotyped 38 single nucleotide polymorphisms (SNPs) in BANK1 on 1892 European-derived SLE patients and 2652 European-derived controls. The strongest associations with SLE and BANK1 were at rs17266594 (corrected P-value=1.97 x 10(-5), odds ratio (OR)=1.22, 95% CI 1.12-1.34) and rs10516487 (corrected P-value=2.59 x 10(-5), OR=1.22, 95% CI 1.11-1.34). Our findings suggest that the association is explained by these two SNPs, confirming previous reports that these polymorphisms contribute to the risk of developing lupus. Analysis of patient subsets enriched for hematological, immunological and renal ACR criteria or the levels of autoantibodies, such as anti-RNP A and anti-SmRNP, uncovers additional BANK1 associations. Our results suggest that BANK1 polymorphisms alter immune system development and function to increase the risk for developing lupus.

Complement cascade plasma proteins play a complex role in the etiopathogenesis of systemic lupus erythematosus (SLE). Hereditary C1q deficiency has been strongly related to SLE; however, there are very few published SLE studies that evaluate the polymorphisms of genes encoding for C1q (A, B and C). In this study, we evaluated 17 single nucleotide polymorphisms (SNPs) across 37 kb of C1QA, C1QB and C1QC in a lupus cohort of individuals of the African-American and Hispanic origin. In a case-only analysis, a significant association at multiple SNPs in the C1QA gene was detected in African Americans with kidney nephritis (best P=4.91 x 10(-6)). In addition, C1QA was associated with SLE in African Americans with a lack of nephritis and accompanying photosensitivity when compared with that in normal controls (P=6.80 x 10(-6)). A similar trend was observed in the Hispanic subjects (P=0.003). Quantitative analysis showed that some SNPs in C1q genes might be correlated with C3 complement levels in an additive model among African Americans (best P=0.0001). The C1QA gene is associated with subphenotypes of lupus in the African-American and Hispanic subjects. Further studies with higher SNP densities in this region and other complement components are necessary to elucidate the complex genetics and phenotypic interactions between complement components and SLE.

In clinical trials testing new treatments for systemic lupus erythematosus (SLE), the failure of the 15-year drug development program for riquent (abetimus sodium) is the latest in a string of disappointments for a disease that has seen no new drugs approved in over 50 years

OBJECTIVE:The aim of this review is to provide an up-to-date overview of treatment approaches for systemic lupus erythematosus (SLE), highlighting the multiplicity and heterogeneity of clinical symptoms that underlie therapeutic decisions. Discussion will focus on the spectrum of currently available therapies, their mechanisms and associated side-effects. Finally, recent developments with biologic treatments including rituximab, epratuzumab, tumor necrosis factor (TNF) inhibitors, and belimumab, will be discussed. RESEARCH DESIGN AND METHODS/METHODS:A MEDLINE literature search for 'systemic lupus erythematosus' and 'damage' and 'treatment' was undertaken for 1996-2008. Secondary citations were obtained from selected manuscripts. Individual case studies were excluded. FINDINGS/RESULTS:SLE is an autoimmune disease involving multiple organ systems, a clinical pattern of flares and remissions, and the presence of anti-nuclear autoantibodies. Whereas early symptoms most frequently involve the skin and joints, disease morbidity and mortality are usually associated with cardiovascular events and damage to major organs, particularly the kidneys. Many of the current therapeutic options are considered to be inadequate because of toxicities, accrual of organ damage, and insufficient control of the underlying disease pathology. Improved understanding of SLE pathogenesis and immunology has led to the identification of new treatment targets. Current interest is mainly focused on the targeted immunosuppressive actions provided by biologic therapy. Although the potential long-term beneficial or harmful effects of the new molecular treatments are unclear, their precise molecular targeting may reveal key relationships within the immune system and advance the cause of individualized molecular medicine. CONCLUSIONS:Biologic compounds that target specific immunologic mechanisms offer a new paradigm in the treatment of SLE, one that may, at best, reverse the course of the disease and, at the very least, might provide some new alternatives to reduce symptoms and limit tissue damage without undue contribution to overall morbidity and mortality.

OBJECTIVE: To study the membrane expression of endothelial protein C receptor (mEPCR) in the renal microvasculature in lupus nephritis (LN) as a potential marker of injury and/or prognostic indicator for response to therapy. METHODS: mEPCR expression was analysed by immunohistochemistry in normal kidney and in 59 biopsies from 49 patients with LN. Clinical parameters were assessed at baseline, 6 months and 1 year. RESULTS: mEPCR was expressed in the medulla, arterial endothelium and cortical peritubular capillaries (PTCs) in all biopsies with LN but not in the cortical PTCs of normal kidney. Positive mEPCR staining in >25% of the PTCs was observed in 16/59 biopsies and associated with poor response to therapy. Eleven (84.6%) of 13 patients with positive staining for mEPCR in >25% of the PTCs and follow-up at 6 months did not respond to therapy, compared with 8/28 (28.6%) with mEPCR staining in < or =25% PTCs, P = 0.0018. At 1 year, 10 (83.3%) of 12 patients with positive mEPCR staining in >25% of the PTCs did not respond to therapy (with two progressing to end-stage renal disease) compared with 8/24 (33.3%) with positive staining in < or =25% of the PTCs, P = 0.0116. Although tubulo-interstitial damage (TID) was always accompanied by mEPCR, this endothelial marker was extensively expressed in the absence of TID suggesting that poor response could not be attributed solely to increased TID. mEPCR expression was independent of International Society of Nephrology/Renal Pathology Society class, activity and chronicity indices. CONCLUSION: Increased mEPCR expression in PTCs may represent a novel marker of poor response to therapy for LN

A combined forward and reverse genetic approach was undertaken to test the candidacy of IRAK1 (interleukin-1 receptor associated kinase-1) as an X chromosome-encoded risk factor for systemic lupus erythematosus (SLE). In studying approximately 5,000 subjects and healthy controls, 5 SNPs spanning the IRAK1 gene showed disease association (P values reaching 10(-10), odds ratio >1.5) in both adult- and childhood-onset SLE, in 4 different ethnic groups, with a 4 SNP haplotype (GGGG) being strongly associated with the disease. The functional role of IRAK1 was next examined by using congenic mouse models bearing the disease loci: Sle1 or Sle3. IRAK1 deficiency abrogated all lupus-associated phenotypes, including IgM and IgG autoantibodies, lymphocytic activation, and renal disease in both models. In addition, the absence of IRAK1 reversed the dendritic cell 'hyperactivity' associated with Sle3. Collectively, the forward genetic studies in human SLE and the mechanistic studies in mouse models establish IRAK1 as a disease gene in lupus, capable of modulating at least 2 key checkpoints in disease development. This demonstration of an X chromosome gene as a disease susceptibility factor in human SLE raises the possibility that the gender difference in SLE may in part be attributed to sex chromosome genes

Immune-mediated nephritis contributes to disease in systemic lupus erythematosus, Goodpasture syndrome (caused by antibodies specific for glomerular basement membrane [anti-GBM antibodies]), and spontaneous lupus nephritis. Inbred mouse strains differ in susceptibility to anti-GBM antibody-induced and spontaneous lupus nephritis. This study sought to clarify the genetic and molecular factors that maybe responsible for enhanced immune-mediated renal disease in these models. When the kidneys of 3 mouse strains sensitive to anti-GBM antibody-induced nephritis were compared with those of 2 control strains using microarray analysis, one-fifth of the underexpressed genes belonged to the kallikrein gene family,which encodes serine esterases. Mouse strains that upregulated renal and urinary kallikreins exhibited less evidence of disease. Antagonizing the kallikrein pathway augmented disease, while agonists dampened the severity of anti-GBM antibody-induced nephritis. In addition, nephritis-sensitive mouse strains had kallikrein haplotypes that were distinct from those of control strains, including several regulatory polymorphisms,some of which were associated with functional consequences. Indeed, increased susceptibility to anti-GBM antibody-induced nephritis and spontaneous lupus nephritis was achieved by breeding mice with a genetic interval harboring the kallikrein genes onto a disease-resistant background. Finally, both human SLE and spontaneous lupus nephritis were found to be associated with kallikrein genes, particularly KLK1 and the KLK3 promoter, when DNA SNPs from independent cohorts of SLE patients and controls were compared. Collectively, these studies suggest that kallikreins are protective disease-associated genes in anti-GBM antibody-induced nephritis and lupus

OBJECTIVE: Systemic lupus erythematosus (SLE) is the prototypical systemic autoimmune disorder, with complex etiology and a strong genetic component. Recently, gene products involved in the interferon pathway have been under intense investigation in terms of the pathogenesis of SLE. STAT-1 and STAT-4 are transcription factors that play key roles in the interferon and Th1 signaling pathways, making them attractive candidates for involvement in SLE susceptibility. METHODS: Fifty-six single-nucleotide polymorphisms (SNPs) across STAT1 and STAT4 on chromosome 2 were genotyped using the Illumina platform, as part of an extensive association study in a large collection of 9,923 lupus patients and control subjects from different racial groups. DNA samples were obtained from the peripheral blood of patients with SLE and control subjects. Principal components analyses and population-based case-control association analyses were performed, and the P values, false discovery rate q values, and odds ratios with 95% confidence intervals were calculated. RESULTS: We observed strong genetic associations with SLE and multiple SNPs located within STAT4 in different ethnic groups (Fisher's combined P = 7.02 x 10(-25)). In addition to strongly confirming the previously reported association in the third intronic region of this gene, we identified additional haplotypic association across STAT4 and, in particular, a common risk haplotype that is found in multiple racial groups. In contrast, only a relatively weak suggestive association was observed with STAT1, probably due to its proximity to STAT4. CONCLUSION: Our findings indicate that STAT4 is likely to be a crucial component in SLE pathogenesis in multiple racial groups. Knowledge of the functional effects of this association, when they are revealed, might improve our understanding of the disease and provide new therapeutic targets

OBJECTIVE: Both genetic and epigenetic factors play an important role in the pathogenesis of lupus. The aim of this study was to examine methyl-CpG-binding protein 2 gene (MECP2) polymorphisms in a large cohort of patients with lupus and control subjects, and to determine the functional consequences of the lupus-associated MECP2 haplotype. METHODS: We genotyped 18 single-nucleotide polymorphisms within MECP2, located on chromosome Xq28, in a large cohort of patients with lupus and control subjects of European descent. We studied the functional effects of the lupus-associated MECP2 haplotype by determining gene expression profiles in B cell lines in female lupus patients with and those without the lupus-associated MECP2 risk haplotype. RESULTS: We confirmed, replicated, and extended the genetic association between lupus and genetic markers within MECP2 in a large independent cohort of lupus patients and control subjects of European descent (odds ratio 1.35, P = 6.65 x 10(-11)). MECP2 is a dichotomous transcription regulator that either activates or represses gene expression. We identified 128 genes that are differentially expressed in lupus patients with the disease-associated MECP2 haplotype; most ( approximately 81%) were up-regulated. Genes that were up-regulated had significantly more CpG islands in their promoter regions compared with genes that were down-regulated. Gene ontology analysis using the differentially expressed genes revealed significant association with epigenetic regulatory mechanisms, suggesting that these genes are targets for MECP2 regulation in B cells. Furthermore, at least 13 of the 104 up-regulated genes are regulated by interferon. The disease-risk MECP2 haplotype was associated with increased expression of the MECP2 transcription coactivator CREB1 and decreased expression of the corepressor histone deacetylase 1. CONCLUSION: Polymorphism in the MECP2 locus is associated with lupus and, at least in part, contributes to the interferon signature observed in lupus patients