Faculty Bibliography

BACKGROUND:Systemic lupus erythematosus (SLE) patients experience a premature and more severe presentation of coronary artery disease. The underlying mechanisms of accelerated coronary artery disease in SLE patients remain to be elucidated. METHODS:By using atherosclerosis combining a SLE murine model, we proved that the onset of SLE aggravates atherosclerosis. Although the onset of SLE reduced blood lipids slightly, immune deviation contributed to aggravated atherosclerosis in lupus mice. Lupus atheroma were characterized by inflammatory cell infiltration, such as gathered dendritic cells, macrophages, and IgG deposition. RESULTS:Decreased lymphocytes and magnified dendritic cells in the spleen were also observed in lupus mice. Hydroxychloroquine prevented atherosclerosis progression mainly by reversing immune status abnormality caused by SLE. Serum interferon alfa levels were not changed in lupus mice. CONCLUSION/CONCLUSIONS:These findings strongly suggested that anti-inflammatory therapies and hydroxychloroquine provide a new possible strategy for treating SLE patients with atherosclerosis.

Throughout our lives we are immersed in, and colonized by, immense and complex microbial communities. These microbiota serve as activators and early sparring partners for the progressive construction of the layers within our immune defenses and are essential to immune homeostasis. Yet, at times imbalances within the microbiota may contribute to metabolic and immune regulatory abnormalities that underlie the development of inflammatory and autoimmune diseases. Here, we review recent progress in investigations of the microbiome, with emphasis on the gut microbiota associated with systemic autoimmunity. In particular, these studies are beginning to illuminate aspects of the pathogenesis of Systemic Lupus Erythematosus, and may suggest that interconnections with specific disease-associated patterns of dysbiosis within gut communities are bidirectional and mutually reinforcing.

Background/Purpose : Systemic lupus erythematosus (SLE) is the archetypic systemic autoimmune disease, for which there is mounting evidence for roles for intestinal bacteria in the development of the systemic autoimmune responses, inflammation, and tissue injury. Whereas Lupus nephritis (LN) is amongst the most serious and potentially life-threatening complications of SLE, earlier diagnosis would speed clinical decision-making and initiation of definitive therapy. To characterize the interrelationships between Lupus host immunity and a candidate gut microbiome pathobiont, we have recently described an assay for detection of serum IgG responses to the commensal anaerobe, Ruminococcus gnavus ( RG ), for identification of individuals with active LN in three US adult Lupus cohort. In the current studies, we further validated this assay and investigated its potential utility in a Swedish cohort. Methods : Patients were recruited and characterized at the Karolinska Hospital, based on ACR criteria, with 38 LN confirmed by renal biopsy, 38 non-renal SLE patients, with 37 age-gender-ethnicity-matched unaffected population (Healthy) controls, 20 ANCA-associated vasculitis (AAV) and 14 IgA Nephropathy (IgAN) patients, based on renal biopsy and/or standard clinical criteria. At our NYU lab, serologic studies were performed with a previously described custom bead-based serologic assay with nuclease-treated RG2 extract and control analytes. Results : LN patients had significantly higher levels of IgG anti-RG2 than Healthy subjects (p< 0.0001,) other nonrenal Lupus patients (p=0.0002), or patients with IgAN (p< 0.0001) or AAV (p< 0.0001)(Wilcoxon rank-sum). There was a modest difference between non-renal Lupus patients, and Healthy subjects (p=0.0283), but no difference between Healthy with IgAN (p=0.273) or AAV (p=0.433). ROC analysis, when LN were compared to Healthy subjects gave an AUC of 0.863 and a Likelihood ratio (LR) of 5.6 at a cut-offof the mean+1 SD for control subjects (p< 0.0001); the LR was 5.8 for a cut-offof a mean+2SD (p< 0.0062), and LR of 7.8 for a cut-offof a mean+3SD (p=0.0284). For LN compared to the disease controls (AAV and IgAN) there was an AUC of 0.828 with a LR of 2.64 with a cut-offof a mean+1SD for disease controls (p=0.01), and the LR of 5.4 with a disease control mean+2SD (p=0.0071)(Figure 1A&B). Conclusion : These findings further validate that serum IgG anti-RG2 levels provide a robust biomarker for the identification of LN, unaffected by gender and age. Importantly, the assay displayed attractive performance characteristics Area under the curve estimates for comparisons of Lupus nephritis patients to A) age-and gender-matched population (Healthy) controls, or B) Disease controls with AAV or IgA nephropathy that represent other forms of glomerulopathy often complicated by pathologic levels of proteinuria. for discrimination of LN patients from population controls as well as those with pathologic proteinuria due to other forms of immune glomerulopathy (i.e., AAV and IgAN). Our findings also provide circumstantial evidence of a possible role for the R. gnavus pathobiont in patients in Sweden, suggesting this pathobiont may be involved in LN at sites geographically distant from the localities in which this association was first identified. (Figure Presented)

BACKGROUND/PURPOSE/OBJECTIVE:To search for a transmissible agent involved in lupus pathogenesis, we investigated the faecal microbiota of patients with systemic lupus erythematosus (SLE) for candidate pathobiont(s) and evaluated them for special relationships with host immunity. METHODS:In a cross-sectional discovery cohort, matched blood and faecal samples from 61 female patients with SLE were obtained. Faecal 16 S rRNA analyses were performed, and sera profiled for antibacterial and autoantibody responses, with findings validated in two independent lupus cohorts. RESULTS:strain-restricted antibodies were detected in those with active nephritis (including Class III and IV) in the discovery cohort, with findings validated in two independent cohorts. CONCLUSION/CONCLUSIONS:These findings suggest a novel paradigm in which specific strains of a gut commensal may contribute to the immune pathogenesis of lupus nephritis.

Background/UNASSIGNED:Patients with rheumatoid arthritis (RA) have an increased risk for cardiovascular disease. We examined the effect of gut microbiota in a mouse model of RA that develops atherosclerosis. Methods/UNASSIGNED:We created three groups of K/BxN female mice that were positive for the anti-glucose-6-phosphate isomerase (GPI) antibody: control diet (CD), high fat diet (HFD), and HFD with hydroxychloroquine (HFD + HCQ). Serological tests were used to detect the serum levels of total cholesterol (TCHO), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), anti-GPI antibody titers, and serum cytokines. Atherosclerotic plaque was determined by histological analysis, and gut microbiota were determined by 16sV4 sequencing. Results/UNASSIGNED:cluster 1, and therefore may be responsible for the reduced RA-associated atherosclerosis and dyslipidemia. Conclusion/UNASSIGNED:Our mouse model of RA indicated that HFD increased ankle width and aggravated atherosclerosis and dyslipidemia, and that HCQ alleviated the dyslipidemia and atherosclerosis, but had no effect on ankle width.

T regulatory (Treg) cells maintain immunological tolerance and organ homeostasis. Activated Treg cells differentiate into effector Treg subsets that acquire tissue-specific functions. Ca²⁺ influx via Ca²⁺ release-activated Ca²⁺ (CRAC) channels formed by STIM and ORAI proteins is required for the thymic development of Treg cells, but its function in mature Treg cells remains unclear. Here we show that deletion of Stim1 and Stim2 genes in mature Treg cells abolishes Ca²⁺ signaling and prevents their differentiation into follicular Treg and tissue-resident Treg cells. Transcriptional profiling of STIM1/STIM2-deficient Treg cells reveals that Ca²⁺ signaling regulates transcription factors and signaling pathways that control the identity and effector differentiation of Treg cells. In the absence of STIM1/STIM2 in Treg cells, mice develop a broad spectrum of autoantibodies and fatal multiorgan inflammation. Our findings establish a critical role of CRAC channels in controlling lineage identity and effector functions of Treg cells.

Staphylococcus aureus is an opportunistic pathogen that causes a range of serious infections associated with significant morbidity, by strains increasingly resistant to antibiotics. However, to date all candidate vaccines have failed to induce protective immune responses in humans. We need a more comprehensive understanding of the antigenic targets important in the context of human infection. To investigate infection-associated immune responses, patients were sampled at initial presentation and during convalescence from three types of clinical infection; skin and soft tissue infection (SSTI), prosthetic joint infection (PJI) and pediatric hematogenous osteomyelitis (PHO). Reactivity of serum IgG was tested with an array of recombinant proteins, representing over 2,652 in-vitro-translated open reading frames (ORFs) from a community-acquired methicillin-resistant S. aureus USA300 strain. High-level reactivity was demonstrated for 104 proteins with serum IgG in all patient samples. Overall, high-level IgG-reactivity was most commonly directed against a subset of secreted proteins. Although based on limited surveys, we found subsets of S. aureus proteins with differential reactivity with serum samples from patients with different clinical syndromes. Together, our studies have revealed a hierarchy within the diverse proteins of the S. aureus "immunome", which will help to advance efforts to develop protective immunotherapeutic agents.