Urine Proteomics and Renal Single Cell Transcriptomics Implicate IL-16 in Lupus Nephritis
OBJECTIVES/OBJECTIVE:Current treatments are effective only in 30% of lupus nephritis patients emphasizing the need for novel therapeutic strategies. To develop mechanistic hypotheses and explore novel biomarkers, we analyzed the longitudinal urinary proteomic profiles in patients with lupus nephritis undergoing treatment. METHODS:We quantified 1,000 urinary proteins in 30 patients with lupus nephritis at the time of the diagnostic renal biopsy and after 3, 6, and 12 months. The proteins and molecular pathways detected in the urine proteome were then analyzed with respect to baseline clinical features and longitudinal trajectories. The intrarenal expression of candidate biomarkers was evaluated using single cell transcriptomics of renal biopsies from lupus nephritis patients. RESULTS:Our analysis revealed multiple biological pathways including chemotaxis, neutrophil activation, platelet degranulation, and extracellular matrix organization that could be noninvasively quantified and monitored in the urine. We identified 237 urinary biomarkers associated with lupus nephritis as compared to controls without SLE. IL-16, CD163, and TGF-Î² mirrored intrarenal nephritis activity. Response to treatment was paralleled by a reduction of urinary IL-16, a CD4 ligand with proinflammatory and chemotactic properties. Single cell RNA sequencing independently demonstrated that IL16 is the second most expressed cytokine by most infiltrating immune cells in lupus nephritis kidneys. IL-16 producing cells were found at key sites of kidney injury. CONCLUSION/CONCLUSIONS:Urine proteomics may profoundly change the diagnosis and management of lupus nephritis by noninvasively monitor active intrarenal biological pathways. These findings implicate IL-16 in lupus nephritis pathogenesis designating it as a potentially treatable target and biomarker.
High Systemic Type I Interferon Activity is Associated with Active Class III/IV Lupus Nephritis
OBJECTIVE:Previous studies suggest a link between high serum type I interferon (IFN) and lupus nephritis (LN). We determined whether serum IFN activity is associated with subtypes of LN and studied renal tissues and cells to understand the impact of IFN in LN. METHODS:). Podocyte cell line gene expression was measured by real-time PCR. RESULTS:expression was not closely co-localized with pDCs. IFN directly activated podocyte cell lines to induce chemokines and proapoptotic molecules. CONCLUSION/CONCLUSIONS:Systemic high IFN is involved in the pathogenesis of severe LN. We do not find co-localization of pDCs with IFN signature in renal tissue, and instead observe the greatest intensity of IFN signature in glomerular areas, which could suggest a blood source of IFN.
Evaluation of Immune Response and Disease Status in SLE Patients Following SARS-CoV-2 Vaccination
OBJECTIVE:To evaluate seroreactivity and disease flares after COVID-19 vaccination in a multi-ethnic/racial cohort of patients with systemic lupus erythematosus (SLE). METHODS:90 SLE patients and 20 healthy controls receiving a complete COVID-19 vaccine regimen were included. IgG seroreactivity to the SARS-CoV-2 spike receptor-binding domain (RBD) and SARS-CoV-2 microneutralization were used to evaluate B cell responses; IFN-Î³ production to assess T cell responses was measured by ELISpot. Disease activity was measured by the hybrid SLE disease activity index (SLEDAI) and flares were assigned by the SELENA/SLEDAI flare index. RESULTS:Overall, fully vaccinated SLE patients produced significantly lower IgG antibodies against SARS-CoV-2 spike RBD than controls. Twenty-six SLE patients (28.8%) generated an IgG response below that of the lowest control (<100 units/ml). In logistic regression analyses, the use of any immunosuppressant or prednisone and a normal anti-dsDNA level prior to vaccination associated with decreased vaccine responses. IgG seroreactivity to the SARS-CoV-2 Spike RBD strongly correlated with the SARS-CoV-2 microneutralization titers and antigen-specific IFN-Î³ production determined by ELISpot. In a subset of patients with poor antibody responses, IFN-Î³ production was likewise diminished. Pre-/post-vaccination SLEDAI scores were similar. Only 11.4% of patients had a post-vaccination flare; 1.3% were severe. CONCLUSION/CONCLUSIONS:In a multi-ethnic/racial study of SLE patients 29% had a low response to the COVID-19 vaccine which was associated with being on immunosuppression. Reassuringly, disease flares were rare. While minimal protective levels remain unknown, these data suggest protocol development is needed to assess efficacy of booster vaccination.
Autoimmune anti-DNA and anti-phosphatidylserine antibodies predict development of severe COVID-19
High levels of autoimmune antibodies are observed in COVID-19 patients but their specific contribution to disease severity and clinical manifestations remains poorly understood. We performed a retrospective study of 115 COVID-19 hospitalized patients with different degrees of severity to analyze the generation of autoimmune antibodies to common antigens: a lysate of erythrocytes, the lipid phosphatidylserine (PS) and DNA. High levels of IgG autoantibodies against erythrocyte lysates were observed in a large percentage (up to 36%) of patients. Anti-DNA and anti-PS antibodies determined upon hospital admission correlated strongly with later development of severe disease, showing a positive predictive value of 85.7% and 92.8%, respectively. Patients with positive values for at least one of the two autoantibodies accounted for 24% of total severe cases. Statistical analysis identified strong correlations between anti-DNA antibodies and markers of cell injury, coagulation, neutrophil levels and erythrocyte size. Anti-DNA and anti-PS autoantibodies may play an important role in the pathogenesis of COVID-19 and could be developed as predictive biomarkers for disease severity and specific clinical manifestations.
Ambulatory fetal heart rate monitoring (FHRM) to surveil pregnancies at risk for congenital heart block [Meeting Abstract]
Background/Purpose: Congenital Heart Block (CHB) complicates 2% of anti-Ro/ SSA antibody positive pregnancies and carries substantial perinatal morbidity and mortality. Almost all survivors require lifelong pacing. Data suggests the potential of anti-inflammatory treatment of 1degree and 2degree CHB in preventing progression to immutable complete block. However, the optimal surveillance strategy to detect rapidly transitioning and potentially reversible conduction disease is unknown. This study addresses the feasibility, acceptance and accuracy of the fetal heart rate and rhythm technique (FHRM) in high risk mothers.
Method(s): Prospective data from the Surveillance To Prevent AV Block Likely to Occur Quickly (STOP BLOQ) study were leveraged. Mothers referred to the study all had commercially positive anti-Ro/ SSA antibodies and were stratified into high and low titers of anti-Ro60 and Ro52 based on a research ELISA which used a threshold cutoff defined as the titer above or below that obtained for 50 mothers with a previous CHB offspring. Mothers with anti-Ro60 or 52 antibodies at or above 1,000 I.U or with a previous CHB offspring, were trained to perform FHRM with an educational video and personal instruction from a pediatric cardiologist. From 17-25 weeks of gestation, FHRM was completed 3x/day in addition to weekly or biweekly fetal echocardiograms (echo). Mothers texted all FHRM sounds to the study's data coordinating center. For those FHRM deemed abnormal by the mothers, texts were immediately sent to an on call pediatric cardiologist who either reassured if FHRM was normal or referred for emergency fetal echo in < 6 hours if abnormal. Postnatal electrocardiograms were evaluated for CHB.
Result(s): Fifty-six mothers with commercial anti-Ro/ SSA positivity were consented to the study. Of these, 37 (inclusive of 6 with previous CHB) performed FRHM since they had high titer anti-Ro60 (n=8) or 52 antibodies (n=7) or both (n=21), albeit one mother had unexpectedly low titer antibodies to both Ro60 and 52 and a child with incomplete CHB 4 yrs prior to enrollment. In total 3,360 FHRM audiotexts were received during the monitoring period. Of these, 39 recordings from 5 concerned mothers prompted an immediate call with the cardiologist. All but 2 recordings were deemed to be normal based on review of the audiotext alone; the cardiologist requested that the patient send repeat recordings after review as part of re-training and to provide additional reassurance. In the 2 cases an emergency echo was completed in < 6 hrs. In both there were premature atrial contractions which confirmed the mother's perception of the FHRM abnormality. However, there was no evidence of conduction disease. All surveillance echoes were normal. Thus, the overall rate of false positive recordings for the concern of a conduction defect perceived by the mothers was 1.1% (38/3360). There were no cases of CHB at birth.
Conclusion(s): These data support that FHRM is feasible and accurate. Mothers can be empowered to detect rhythm abnormalities with very few false perceptions thus supporting this technique to substantially enhance the management of anti-Ro/ SSA pregnancies
Putting the pieces on the board: Mapping SLE nephritis biopsies from the accelerating medicines project using high-density immunofluorescence imaging [Meeting Abstract]
Background/Purpose: The Accelerating Medicines Project (AMP) has enabled significant increases in understanding of SLE nephritis pathology, providing a profile of dozens of leukocyte subsets within affected kidneys by single-cell RNA sequencing of nephritis biopsies. While these results suggest a complex network of interactions between cell populations during nephritis, the spatial positioning of these cells is lost during the sequencing process. Inferred interactions between the diverse identified cell types would be greatly strengthened by detailed spatial information, placing these cells in context with each other and with the surrounding structures of the kidney.
Method(s): In consultation with AMP, we have used CODEX, a multicycle imaging technology allowing for staining of up to 40 targets on a single tissue sample without tissue degradation, to capture preliminary images of the AMP tissue biopsies available at New York University. Extensive antibody screening, sample preparation, optimization of antigen retrieval, and imaging steps are required, which remain under active optimization to allow for imaging the entirety of the AMP biopsy cohort available at the Grossman School of Medicine, which has been fully processed for future staining.
Result(s): At present we are able to image sixteen targets capturing dense interstitial T and B cell infiltrates, intratubular and interstitial myeloid populations, and sparser glomerular infiltrating cells in our demonstration cohort, with clear imaging of the glomeruli, tubules, and interstitial spaces. Further targets will be added as they are optimized, further allowing subsetting of T, B, and myeloid populations, with the goal of capturing the populations identified previously in single-cell sequencing.
Conclusion(s): CODEX imaging of renal biopsy samples provides spatial context for prior observations across a range of SLE nephritis samples, with complex interstitial populations found around glomeruli and tubules in active disease. Deeper profiling with expanded antigen targets to enable further sub-population phenotyping and activation states and imaging of the full cohort of biopsies available at NYU will provide a spatial atlas to SLE nephritis and further reveal underlying mechanisms of disease
Platelet secreted LGALS3BP induces a pro-inflammatory phenotype in systemic lupus erythematosus [Meeting Abstract]
Background/Purpose: Systemic Lupus Erythematosus (SLE) is a complex chronic heterogeneous autoimmune disease, which increases the risk of atherothrombosis. In addition to their well described role in thrombosis and hemostasis, platelets are key mediators of inflammation and have immune effector cell properties. This study was initiated to investigate the role of platelet associated Lectin Galactoside-binding Soluble 3 Binding Protein (LGALS3BP), which binds to macrophage-associated lectin Mac-2, as a mediator of inflammation in SLE and potential biomarker associated with clinical phenotypes.
Method(s): RNA transcriptome analysis was performed on platelets isolated from 51 patients with SLE (not taking aspirin or anticoagulants) and 18 age, sex and race/ethnicity matched controls. LGALS3BP protein expression was determined in platelet releasates by ELISA and western blot analysis. Gene and protein expression of LGALS3BP in Megakaryocyte cell line (MEG-01) was investigated upon stimulation with IFN-alpha. Correlations between circulating serum LGALS3BP and LGALS3BP platelet mRNA and releasates were assessed. Subsequently, correlation analysis between clinical features of SLE and circulating serum LGLAS3BP was performed. Finally, the effects of platelets and LGALS3BP on macrophage inflammatory response were studied in vitro.
Result(s): Platelet transcriptome analysis revealed that LGALS3BP was one of the most differentially expressed transcripts in SLE versus matched-healthy controls (Fold change, 3.9, adjusted P-value = 2.5 x 10-11) (Figure1A). Consistently, LGALS3BP in platelet releasates was significantly higher in 40 patients with SLE than 20 controls (p = 0.002) (Figure1B). Platelet LGALS3BP gene and protein expression were highly correlated with circulating LGALRS3BP in serum (r2 = 0.370, p = 0.003 and r2 = 0.689, p < 0.0001 respectively) (Figure1E and F). LGALS3BP measured in serum of 115 patients with SLE correlated with the SELENA SLEDAI hybrid disease activity index (r2= 0.322, p = 0.0005) (Figure1G). In particular, higher serum LGALS3BP levels were observed in SLE patients with lupus nephritis compared to those with SLE and inactive disease (P=0.0001) (Figure1H). In longitudinal analysis of 22 patients without proteinuria at baseline who went on to develop proteinuria over time, circulating plasma LGALS3BP tracked with flares of nephritis (p=0.06). In vitro, IFN-alpha induced the expression and production of LGALS3BP in MEG-01 cells in a dose dependent manner (Figure2A, B and C), which was completely inhibited by IFN-alpha neutralizing antibody (Figure2D, E and F). Recombinant LGALS3BP (Figure 3A and B) and Platelet releasates from SLE (Figure 3C) induced the production of pro-inflammatory cytokines such as IL-8 (p=0.04) and IL-6 (p=0.073) by macrophages.
Conclusion(s): These data show that platelets isolated from patients with SLE highly express and secrete LGALS3BP which induces a proinflammatory macrophage and is associated with SLE disease clinical phenotype. LGALS3BP may contribute to pathogenesis and serve as a novel biomarker of SLE disease activity
Development of biomarker models to identify hla-related microbiome associations in anti-ro+ mothers of children with neonatal lupus [Meeting Abstract]
Background/Purpose: Anti-Ro autoantibody production often precedes the development of Systemic Lupus Erythematosus (SLE) or Sjogren's syndrome (SS) by years. For anti-Ro+ mothers enrolled in the Research Registry for Neonatal Lupus (RRNL), progression to SS or SLE occurs in about a quarter, while most remain asymptomatic or develop only minor rheumatic symptoms (Asym/UAS). Thus, RRNL mothers uniquely offer a promise to identify genotype-phenotype relationships that are important to preclinical autoimmunity. Since multiple SLE risk alleles from Class II HLA genes are present in anti-Ro+ mothers, we examined interactions of specific microbiome taxa with Class II HLA by independent analytic paths with the goal to identify HLA-related microbiome associations in Anti-Ro+ Mothers of Children with Neonatal Lupus.
Method(s): Subjects included 125 RRNL mothers and 23 healthy controls. Stool microbiomes of anti-Ro+ women in RRNL (Asym/UAS, SS/SLE), and healthy controls (HC) were processed using 16S ribosomal RNA sequencing. Sera/ plasma were evaluated for cytokines and autoantibody levels. Alleles from HLA Class II genes were genotyped using NextGen sequencing of HLA region or imputed (HIBAG) from GWAS data. Independent analytic paths sought to explore associations of specific taxa and class II HLA included: 1) use of a cumulative logit model to test interactions between FDR significant genera and HLA alleles and 2) assignment of SLE, SS, UAS patients and HC to molecular phenotype clusters by Random Forest (RF), an unsupervised machine learning tool using Z-score transformed cytokine soluble mediators and autoantibody values with settings and the gap statistic that were used to estimate the optimal number of patients and HC within clusters. The overlapping distribution of SS/SLE, HLA alleles and taxa at clusters were then examined.
Result(s): Findings related to DRB1*15:01 and an interaction with genera of the Ruminococcaceae family were tested. Oscillibacter, with FDR-adjusted significance was shown to exhibit evidence of an interaction (P=0.033 (OR=0.60 (0.37-0.96)). In order to authenticate that SLE HLA risk alleles modify the strength of the association, we examined the molecular phenotype clusters from RF clustering. Radar plots were used to visualize the distribution HLA alleles and the enrichment of microbiome taxa within these clinically relevant phenotypic clusters (Figure 1). DRB1*1501 shows enrichment at cluster 4. Interestingly, the distribution of Oscillibacter, but not Coprococcus 3 was nearly superimposable with the Class II HLA allele with enrichment at cluster 4. However, the distribution of DRB1*1501 was not enriched at cluster profiles representing evaluations of DRB1*0301 and SS/SLE disease classification (Figure 2) demonstrating a limitation of DRB1*1501 to predict risk for transition from benign to pathologic autoimmunity in anti-Ro+ mothers of children with neonatal lupus.
Conclusion(s): These data support the use of molecular phenotypes that are linked to genetic-environmental interactions to identify HLA-related microbiome associations
Modeling of clinical phenotypes in SLE based on platelet transcriptomic analysis and FCGR2A biallelic variants [Meeting Abstract]
Background/Purpose: The clinical heterogeneity of SLE with its complex pathogenesis remains challenging as we strive to provide optimal management. The contribution of platelets to endovascular homeostasis, inflammation and immune regulation highlights their potential importance in SLE. Prior work from our group showed that the Fcgamma receptor type IIa (FcgammaRIIa)-R/H131 biallelic polymorphism is associated with increased platelet activity and cardiovascular risk in SLE. The study was initiated to investigate the platelet transcriptome in patients with SLE and evaluate its association across FcgammaRIIa genotypes and distinct clinical features.
Method(s): RNA-sequencing was done on platelets isolated from 51 patients fulfilling criteria for the classification of SLE based on recent EULAR/ACR definitions, and 18 healthy controls matched on age, sex, and race. Unsupervised clustering, differential gene expression, and gene set enrichment analysis (GSEA) were used to analyze differences between SLE patients and controls, and SLE subpopulations, based on SELENA SLEDAI Hybrid disease activity, specific organ manifestations, and FcgammaRIIa genotype. Weighted Gene Correlation Network Analysis (WGCNA) was performed to create a modular transcriptomic framework.
Result(s): Our cross-sectional SLE cohort (N=51, age = 41.1+/-12.3, 100% female, 45% Hispanic, 24% black, 22% Asian, 51% white, SLEDAI = 4.4+/-4.2) was comprised of patients consecutively enrolled excluding those on aspirin or anticoagulants. Compared to the 18 controls, there were 2290 (p.adj < 0.05) differentially expressed genes. ( Figure 1 A, B) GSEA revealed positive enrichment for pathways related to interferon response, TNFa signaling, and coagulation in SLE. ( Figure 1C) WGCNA was used to create a modular transcriptomic framework. ( Figure 2A ) Modules enriched for platelet activity, immune response, and WNT signaling were significantly increased in SLE versus controls. Moreover, modules enriched for interferon response and WNT signaling paralleled increases in disease activity. ( Figure 2B) When analyzing patients with proteinuria, modules associated with oxidative phosphorylation and platelet activity were unexpectedly decreased. (Figure 2C) Analyzing the ratio of fold changes between SLE/Control vs SLE Proteinuria/SLE No Proteinuria, genes increased in SLE and those with proteinuria were enriched for immune effector processes, while genes increased in SLE but decreased in proteinuria were enriched for coagulation and cell adhesion. (Figure 2D) The module enriched for FCR activation was decreased in SLE and was affected by the FcgammaRIIa genotype. (Figure 3A) FcgammaRIIa R131 and H131 patients showed significantly different platelet transcriptomes. (Figure 3B) The combination of SLE with an FcgammaRIIa R131 variant leads to a significant increase in the platelet activity module not seen in controls. (Figure 3C)
Conclusion(s): These analyses reveal that SLE patients have a significantly different platelet transcriptome from controls, different phenotypic presentations of SLE patients associate with distinct platelet transcriptomic signatures, and FCGR2a variants may differentially influence the role of platelets in the contribution to SLE disease activity
Autoantibody-mediated impairment of DNASE1L3 activity in sporadic systemic lupus erythematosus
Antibodies to double-stranded DNA (dsDNA) are prevalent in systemic lupus erythematosus (SLE), particularly in patients with lupus nephritis, yet the nature and regulation of antigenic cell-free DNA (cfDNA) are poorly understood. Null mutations in the secreted DNase DNASE1L3 cause human monogenic SLE with anti-dsDNA autoreactivity. We report that >50% of sporadic SLE patients with nephritis manifested reduced DNASE1L3 activity in circulation, which was associated with neutralizing autoantibodies to DNASE1L3. These patients had normal total plasma cfDNA levels but showed accumulation of cfDNA in circulating microparticles. Microparticle-associated cfDNA contained a higher fraction of longer polynucleosomal cfDNA fragments, which bound autoantibodies with higher affinity than mononucleosomal fragments. Autoantibodies to DNASE1L3-sensitive antigens on microparticles were prevalent in SLE nephritis patients and correlated with the accumulation of cfDNA in microparticles and with disease severity. DNASE1L3-sensitive antigens included DNA-associated proteins such as HMGB1. Our results reveal autoantibody-mediated impairment of DNASE1L3 activity as a common nongenetic mechanism facilitating anti-dsDNA autoreactivity in patients with severe sporadic SLE.