CaMK4 controls follicular helper T cell expansion and function during normal and autoimmune T-dependent B cell responses.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by dysregulated B cell compartment responsible for the production of autoantibodies. Here, we show that T cell-specific expression of calcium/calmodulin-dependent protein kinase IV (CaMK4) leads to T follicular helper (Tfh) cells expansion in models of T-dependent immunization and autoimmunity. Mechanistically, CaMK4 controls the Tfh-specific transcription factor B cell lymphoma 6 (Bcl6) at the transcriptional level through the cAMP responsive element modulator α (CREMα). In the absence of CaMK4 in T cells, germinal center formation and humoral immunity is impaired in immunized mice, resulting in reduced anti-dsDNA titres, as well as IgG and complement kidney deposition in the lupus-prone B6.lpr mouse. In human Tfh cells, CaMK4 inhibition reduced BCL6 expression and IL-21 secretion ex vivo, resulting in impaired plasmablast formation and IgG production. In patients with SLE, CAMK4 mRNA levels in Tfh cells correlated with those of BCL6. In conclusion, we identify CaMK4/CREMα as a driver of T cell-dependent B cell dysregulation in autoimmunity.

Dynamics of corticocortical brain functional connectivity relevant to therapeutic response to biologics in inflammatory arthritis.

Aberrant functional connectivity (FC) of the brain regions, evaluated by functional magnetic resonance imaging (fMRI), affects clinical courses in inflammatory arthritis (IA). The static analysis methods would be simplistic to estimate the whole picture of resting-state brain function because blood oxygen level-dependent (BOLD) signals fluctuate over time. The effects of FC dynamics on clinical course are unknown in IA. Therefore, we aimed to evaluate dynamic FC for therapeutic responsiveness to biologics in IA patients. We analyzed resting-state fMRI data of 64 IA patients in 2 cohorts. Dynamic FC was derived as a correlation coefficient of the windowed BOLD signal time series. We determined representative whole-brain dynamic FC patterns by k-means++ cluster analysis, leading to 4 distinct clusters. In the first cohort, occurrence probability of the distinct cluster was associated with favorable therapeutic response in disease activity and patients' global assessment, which was validated by the second cohort. The whole-brain FC of the distinct cluster indicated significantly increased corticocortical connectivity, and probabilistically decreased after therapy in treatment-effective patients compared with -ineffective patients. Taken together, frequent emergence of corticocortical connections was associated with clinical outcomes in IA. The coherence of corticocortical interactions might affect pain modulation, possibly relevant to therapeutic satisfaction.

Itaconate ameliorates autoimmunity by modulating T cell imbalance via metabolic and epigenetic reprogramming.

Dysregulation of Th17 and Treg cells contributes to the pathophysiology of many autoimmune diseases. Herein, we show that itaconate, an immunomodulatory metabolite, inhibits Th17 cell differentiation and promotes Treg cell differentiation by orchestrating metabolic and epigenetic reprogramming. Mechanistically, itaconate suppresses glycolysis and oxidative phosphorylation in Th17- and Treg-polarizing T cells. Following treatment with itaconate, the S-adenosyl-L-methionine/S-adenosylhomocysteine ratio and 2-hydroxyglutarate levels are decreased by inhibiting the synthetic enzyme activities in Th17 and Treg cells, respectively. Consequently, these metabolic changes are associated with altered chromatin accessibility of essential transcription factors and key gene expression in Th17 and Treg cell differentiation, including decreased RORγt binding at the Il17a promoter. The adoptive transfer of itaconate-treated Th17-polarizing T cells ameliorates experimental autoimmune encephalomyelitis. These results indicate that itaconate is a crucial metabolic regulator for Th17/Treg cell balance and could be a potential therapeutic agent for autoimmune diseases.

Inhibitor of NF-κB Kinase Subunit ε Contributes to Neuropsychiatric Manifestations in Lupus-Prone Mice Through Microglial Activation.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by multiorgan dysfunction. Neuropsychiatric SLE (NPSLE) occurs in 30-40% of lupus patients and is the most severe presentation of SLE, frequently resulting in limitation of daily life. Recent studies have shown that microglia, tissue-resident macrophages in the central nervous system, are involved in the pathogenesis of NPSLE. This study was undertaken to explore new therapeutic targets for NPSLE focusing on microglia. METHODS: RNA sequencing of microglia in MRL/lpr, lupus-prone mice, as well as that of microglia cultured in vitro with cytokines were performed. A candidate gene, which could be a therapeutic target for NPSLE, was identified, and its role in microglial activation and phagocytosis was investigated using specific inhibitors and small interfering RNA. The effect of intracerebroventricular administration of the inhibitor on the behavioral abnormalities of MRL/lpr was also evaluated. RESULTS: Transcriptome analysis revealed the up-regulation of Ikbke, which encodes the inhibitor of NF-κB kinase subunit ɛ (IKBKε) in both microglia from MRL/lpr mice and cytokine-stimulated microglia in vitro. Intracerebroventricular administration of an IKBKε inhibitor ameliorated cognitive function and suppressed microglial activation in MRL/lpr mice. Mechanistically, IKBKε inhibition reduced glycolysis, which dampened microglial activation and phagocytosis. CONCLUSION: These findings suggest that IKBKε plays a vital role in the pathogenesis of NPSLE via microglial activation, and it could serve as a therapeutic target for NPSLE.

Cytokine and chemokine multiplex analysis-based exploration for potential treatment and prognostic prediction in large-vessel vasculitis: A preliminary observational study.

Large-vessel vasculitis (LVV) is subclassified into two phenotypes; Takayasu arteritis and giant cell arteritis. Although the pathogenesis of LVV is not fully established, IL-6-IL-17 axis and IL-12-IFN-γ axis play critical roles in the disease development. We aimed to clarify the association between the disease state and cytokine/chemokine levels, to assess disease course as prognosis and to predict regulators in patients with LVV using the blood profiles of multiple cytokines/chemokines. This retrospective analysis comprised 35 LVV patients whose blood were collected, and multiplex cytokine/chemokine analysis with 28 analytes was performed. The differences of cytokines/chemokines corresponding disease status, upstream regulator analysis, pathway analysis and cluster analysis were conducted using the cytokines/chemokines profile. Relapse-free survival rate was calculated with Kaplan-Meier analysis in the classified clusters. In the robust analysis, IL-4, CCL2/MCP-1, TNFSF13/APRIL, TNFSF13B/BAFF, CHI3L1 and VEGF-A levels were significantly changed after treatment. Untreated LVV patients demonstrated activation of NFκB-related molecules and these patients are potentially treated with JAK/STAT inhibitors, anti-TNF-α inhibitors and IL-6 inhibitors. Cluster analysis in active LVV patients revealed two clusters including one with high blood levels of IL-1ß, IL-6, IL-17, IL-23 and CCL20/MIP-3. A subgroup of the LVV patients showed activated IL-17 signature with high relapse frequency, and JAK/TyK2 inhibitors and IFN-γ inhibitors were detected as potentially upstream inhibitors. Blood cytokine/chemokine profiles would be useful for prediction of relapse and potentially contributes to establish therapeutic strategy as precision medicine in LVV patients.

Pathogenic neuropsychiatric effect of stress-induced microglial interleukin 12/23 axis in systemic lupus erythematosus.

OBJECTIVES: The central nervous system disorder in systemic lupus erythematosus (SLE), called neuropsychiatric lupus (NPSLE), is one of the most severe phenotypes with various clinical symptoms, including mood disorder, psychosis and delirium as diffuse neuropsychological manifestations (dNPSLE). Although stress is one of the aggravating factors for neuropsychiatric symptoms, its role in the pathogenesis of dNPSLE remains to be elucidated. We aimed to investigate stress effects on the neuropsychiatric pathophysiology in SLE using lupus-prone mice and patients' data. METHODS: Sleep disturbance stress (SDS) for 2 weeks was placed on 6-8-week-old female MRL/lpr and control mice. Behavioural phenotyping, histopathological analyses and gene and protein expression analyses were performed to assess SDS-induced neuroimmunological alterations. We also evaluated cytokines of the cerebrospinal fluid and brain regional volumes in patients with dNPSLE and patients with non-dNPSLE. RESULTS: SDS-subjected MRL/lpr mice exhibited less anxiety-like behaviour, whereas stressed control mice showed increased anxiety. Furthermore, stress strongly activated the medial prefrontal cortex (mPFC) in SDS-subjected MRL/lpr. A transcriptome analysis of the PFC revealed the upregulation of microglial activation-related genes, including Il12b. We confirmed that stress-induced microglial activation and the upregulation of interleukin (IL) 12/23p40 proteins and increased dendritic spines in the mPFC of stressed MRL/lpr mice. IL-12/23p40 neutralisation and tyrosine kinase 2 inhibition mitigated the stress-induced neuropsychiatric phenotypes of MRL/lpr mice. We also found a higher level of cerebrospinal fluid IL-12/23p40 and more atrophy in the mPFC of patients with dNPSLE than those with non-dNPSLE. CONCLUSIONS: The microglial IL-12/23 axis in the mPFC might be associated with the pathogenesis and a promising therapeutic target for dNPSLE.

Biological insights into systemic lupus erythematosus through an immune cell-specific transcriptome-wide association study.

OBJECTIVE: Genome-wide association studies (GWAS) have identified >100 risk loci for systemic lupus erythematosus (SLE), but the disease genes at most loci remain unclear, hampering translation of these genetic discoveries. We aimed to prioritise genes underlying the 110 SLE loci that were identified in the latest East Asian GWAS meta-analysis. METHODS: We built gene expression predictive models in blood B cells, CD4+ and CD8+ T cells, monocytes, natural killer cells and peripheral blood cells of 105 Japanese individuals. We performed a transcriptome-wide association study (TWAS) using data from the latest genome-wide association meta-analysis of 208 370 East Asians and searched for candidate genes using TWAS and three data-driven computational approaches. RESULTS: TWAS identified 171 genes for SLE (p<1.0×10-5); 114 (66.7%) showed significance only in a single cell type; 127 (74.3%) were in SLE GWAS loci. TWAS identified a strong association between CD83 and SLE (p<7.7×10-8). Meta-analysis of genetic associations in the existing 208 370 East Asian and additional 1498 cases and 3330 controls found a novel single-variant association at rs72836542 (OR=1.11, p=4.5×10-9) around CD83. For the 110 SLE loci, we identified 276 gene candidates, including 104 genes at recently-identified SLE novel loci. We demonstrated in vitro that putative causal variant rs61759532 exhibited an allele-specific regulatory effect on ACAP1, and that presence of the SLE risk allele decreased ACAP1 expression. CONCLUSIONS: Cell-level TWAS in six types of immune cells complemented SLE gene discovery and guided the identification of novel genetic associations. The gene findings shed biological insights into SLE genetic associations.

Aberrant functional connectivity between anterior cingulate cortex and left insula in association with therapeutic response to biologics in inflammatory arthritis.

BACKGROUND: Brain activity is reported to be associated with individual pain susceptibility and inflammatory status, possibly contributing to disease activity assessment in inflammatory arthritis (IA) including rheumatoid arthritis (RA) and spondyloarthritis (SpA). However, what alteration of brain function associated with disease activity and therapeutic effectiveness in IA remains unclear. We aimed to identify the alterations of brain functional connectivity (FC) shared in both RA and SpA, and evaluate its relationship to anti-rheumatic treatment response using functional magnetic resonance imaging (MRI). PATIENTS AND METHODS: Structural and resting-state functional MRI data were acquired from patients with IA, patients with osteoarthritis (OA) and heathy controls (HCs). Two datasets were adopted to derive (51 IA, 56 OA, and 17 HCs) and validate (31 IA) the observations. 33 IA patients in the derivation dataset and all the patients in validation dataset required biological treatment and were clinically evaluated before and after therapy. Via whole-brain pair-wise FC analyses, we analyzed IA-specific FC measures relevant to therapeutic response to biologics. RESULTS: The value of FC between left insular cortex (IC) and anterior cingulate cortex (ACC) was significantly low in IA patients compared with OA patients and HCs. We demonstrated that the FC between left anterior long insular gyrus as a subdivision of IC and ACC was significantly associated with therapeutic response to biologics regarding the improvement of patients' global assessment (PGA) in both derivation and validation datasets. CONCLUSION: Disease-specific resting-state FC provides a means to assess the therapeutic improvement of PGA and would be a clinical decision-making tool with predictability for treatment response in both RA and SpA.

Glycogen synthase kinase 3ß/CCR6-positive bone marrow cells correlate with disease activity in multicentric Castleman disease-TAFRO.

Multicentric Castleman disease-thrombocytopenia, anasarca, reticulin fibrosis of bone marrow, renal dysfunction and organomegaly (MCD-TAFRO)-is an emergent phenotype characterized by lymphoproliferation, fluid collection, hemocytopenia and multiple organopathy. Although studies have demonstrated an aberrant blood cytokine/chemokine profile referred to as "chemokine storm", the pathogenesis remains unclear. We aimed to identify pathogenic key molecules, potential diagnostic targets and therapeutic markers in MCD-TAFRO using serum cytokine/chemokine profiles. We performed the targeted cytokine/chemokine multiplex analysis in six cases of MCD-TAFRO with remission or non-remission status. We observed significant changes in serum concentrations of CCL2, CCL5, and Chitinase-3-like-1 in the MCD-TAFRO patients with active state compared to inactive state. Ingenuity pathway analysis revealed that glycogen synthase kinase 3 (GSK3) and CCR6, which is expressed in megakaryocytes, were detected as upstream positive regulators for activating MCD-TAFRO status. More GSK3ß+ CCR6+ cells like megakaryocytes were detected in the bone marrow of patients with MCD-TAFRO than in those with systemic lupus erythematosus, MCD-not otherwise specified or autoimmune haemophagocytic lymphohistiocytosis. The cellularity of GSK3ß+ CCR6+ cells was correlated with disease activity, including thrombocytopenia and anaemia. In conclusion, GSK3ß and CCR6 of bone marrow cells were potentially involved in the pathogenesis of MCD-TAFRO and may act as diagnostic targets and therapeutic markers.

Novel susceptibility loci for steroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus.

Osteonecrosis of the femoral head (ONFH) involves necrosis of bone and bone marrow of the femoral head caused by ischemia with unknown etiology. Previous genetic studies on ONFH failed to produce consistent results, presumably because ONFH has various causes with different genetic backgrounds and the underlying diseases confounded the associations. Steroid-associated ONFH (S-ONFH) accounts for one-half of all ONFH, and systemic lupus erythematosus (SLE) is a representative disease underlying S-ONFH. We performed a genome-wide association study (GWAS) to identify genetic risk factors for S-ONFH in patients with SLE. We conducted a two-staged GWAS on 636 SLE patients with S-ONFH and 95 588 non-SLE controls. Among the novel loci identified, we determined S-ONFH-specific loci by comparing allele frequencies between SLE patients without S-ONFH and non-SLE controls. We also used Korean datasets comprising 148 S-ONFH cases and 37 015 controls to assess overall significance. We evaluated the functional annotations of significant variants by in silico analyses. The Japanese GWAS identified 4 significant loci together with 12 known SLE susceptibility loci. The four significant variants showed comparable effect sizes on S-ONFH compared with SLE controls and non-SLE controls. Three of the four loci, MIR4293/MIR1265 [odds ratio (OR) = 1.99, P-value = 1.1 × 10-9)], TRIM49/NAALAD2 (OR = 1.65, P-value = 4.8 × 10-8) and MYO16 (OR = 3.91, P-value = 4.9 × 10-10), showed significant associations in the meta-analysis with Korean datasets. Bioinformatics analyses identified MIR4293, NAALAD2 and MYO16 as candidate causal genes. MIR4293 regulates a PPARG-related adipogenesis pathway relevant to S-ONFH. We identified three novel susceptibility loci for S-ONFH in SLE.

Meta-analysis of 208370 East Asians identifies 113 susceptibility loci for systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE), an autoimmune disorder, has been associated with nearly 100 susceptibility loci. Nevertheless, these loci only partially explain SLE heritability and their putative causal variants are rarely prioritised, which make challenging to elucidate disease biology. To detect new SLE loci and causal variants, we performed the largest genome-wide meta-analysis for SLE in East Asian populations. METHODS: We newly genotyped 10 029 SLE cases and 180 167 controls and subsequently meta-analysed them jointly with 3348 SLE cases and 14 826 controls from published studies in East Asians. We further applied a Bayesian statistical approach to localise the putative causal variants for SLE associations. RESULTS: We identified 113 genetic regions including 46 novel loci at genome-wide significance (p<5×10-8). Conditional analysis detected 233 association signals within these loci, which suggest widespread allelic heterogeneity. We detected genome-wide associations at six new missense variants. Bayesian statistical fine-mapping analysis prioritised the putative causal variants to a small set of variants (95% credible set size ≤10) for 28 association signals. We identified 110 putative causal variants with posterior probabilities ≥0.1 for 57 SLE loci, among which we prioritised 10 most likely putative causal variants (posterior probability ≥0.8). Linkage disequilibrium score regression detected genetic correlations for SLE with albumin/globulin ratio (rg=-0.242) and non-albumin protein (rg=0.238). CONCLUSION: This study reiterates the power of large-scale genome-wide meta-analysis for novel genetic discovery. These findings shed light on genetic and biological understandings of SLE.

Myofascia-dominant involvement on whole-body MRI as a risk factor for rapidly progressive interstitial lung disease in dermatomyositis.

OBJECTIVE: Rapidly progressive interstitial lung disease (RPILD) is a major cause of death in patients with DM. Although clinically amyopathic DM (CADM) represents risk for RPILD, the incidence rate of RPILD in patients with CADM varies widely. Whole-body (WB) MRI can reveal involvement of systemic muscle and myofascia. The objective of this study was to explore the risk factors for RPILD in patients with DM using WB-MRI. METHODS: This retrospective study comprised 41 patients with DM who underwent WB-MRI before the initiation of treatment in our hospital. Muscular and myofascial signals were scored on 42 muscular groups. The myofascia/muscle ratio was calculated and used to define the relevance of myofascia-dominant involvement. RPILD was defined as worsening of dyspnoea, hypoxaemia and radiographic ILD/fibrosis within 3 months from the onset of respiratory symptoms. RESULTS: Among the 41 patients, 17 had CADM and 30 had ILD, including 10 patients with RPILD. All patients including those with CADM showed abnormal signal intensity in both muscle and myofascia (median score: 15 and 23, respectively). Muscle signal scores positively correlated with the serum creatine kinase level (r = 0.714; P< 0.001). Patients with RPILD showed a significantly higher myofascia/muscle ratio than those without RPILD (1.929 vs 1.200; P= 0.027). Logistic regression analysis identified higher myofascia/muscle ratio as independent risk factors for developing RPILD. CONCLUSION: Myofascia-dominant involvement was defined and appreciated in patients with DM using WB-MRI. This may be one of the risk factors for RPILD.

A case report dysregulated neutrophil extracellular traps in a patient with propylthiouracil-induced anti-neutrophil cytoplasmic antibody-associated vasculitis.

RATIONALE: Neutrophil extracellular traps (NETs) are immune defence systems that release extracellular chromatin and myeloid granules including myeloperoxidase (MPO) to kill pathogens. An experimental animal study recently demonstrated that disordered NETs induced by propylthiouracil (PTU) could contribute to the production of MPO anti-neutrophil cytoplasmic antibody (ANCA) and the development of ANCA-associated vasculitis (AAV). However, the role of dysregulated NETs in the pathogenesis of human AAV remains unclear. PATIENT CONCERNS: We report a 19-year-old woman with Graves' disease on PTU presented fever, polyarthralgia, and lung hemorrhage with high titer of MPO-ANCA. This patient had a variety of atypical ANCAs and disordered NETs in vitro. DIAGNOSES: A diagnosis of PTU-induced AAV (PTU-AAV). INTERVENTIONS: The PTU was discontinued and she was treated with immunosuppressants and plasmapheresis for reducing pathogenic autoantibodies. OUTCOMES: Clinical manifestations including fever, polyarthralgia, and lung hemorrhage were on remission with a decrease of dysregulated NETs. LESSONS: The clinical course of this PTU-AAV case indicated that dysregulated NETs would play a role in the development of ANCA and the pathogenesis of AAV.

Anti-TIF1γ antibody predicted malignancy of thymic tumor with dermatomyositis as an "autoimmune tumor marker": A case report.

RATIONALE: An association between inflammatory myopathy and malignancy has been recognized particularly in patients positive for anti-transcription intermediary factor 1γ (TIF1γ) antibody. We report a case of anti-TIF1γ antibody positive dermatomyositis (DM) associated with thymic carcinoma which radiographically mimicked benign tumor. PATIENT CONCERNS: A 72-year-old man presented typical characteristic cutaneous manifestations and proximal muscle weakness with elevated levels of myogenic enzymes. An anterior mediastinal tumor was detected by computed tomography (CT) scan and radiographically assessed to be benign with distinct borders and little enhancement. DIAGNOSES: DM with anti-TIF1γ antibody and thymic carcinoma. INTERVENTIONS: Thymic carcinoma was completely resected by surgery. DM was induced into remission with glucocorticoid treatment. OUTCOMES: The serum level of myogenic enzyme remained within normal range under low-dose glucocorticoid maintenance. No evidence of carcinoma recurrence with CT scan was observed at 1-year follow up. LESSONS: The present case indicated that anti-TIF1γ antibody would play a role as the "autoimmune tumor marker" in patients with inflammatory myopathy.