Single-cell multi-omics analysis identifies two distinct phenotypes of newly-onset microscopic polyangiitis.

The immunological basis of the clinical heterogeneity in autoimmune vasculitis remains poorly understood. In this study, we conduct single-cell transcriptome analyses on peripheral blood mononuclear cells (PBMCs) from newly-onset patients with microscopic polyangiitis (MPA). Increased proportions of activated CD14+ monocytes and CD14+ monocytes expressing interferon signature genes (ISGs) are distinctive features of MPA. Patient-specific analysis further classifies MPA into two groups. The MPA-MONO group is characterized by a high proportion of activated CD14+ monocytes, which persist before and after immunosuppressive therapy. These patients are clinically defined by increased monocyte ratio in the total PBMC count and have a high relapse rate. The MPA-IFN group is characterized by a high proportion of ISG+ CD14+ monocytes. These patients are clinically defined by high serum interferon-alpha concentrations and show good response to immunosuppressive therapy. Our findings identify the immunological phenotypes of MPA and provide clinical insights for personalized treatment and accurate prognostic prediction.

Secretion of mitochondrial DNA via exosomes promotes inflammation in Behçet's syndrome.

Mitochondrial DNA (mtDNA) leakage into the cytoplasm can occur when cells are exposed to noxious stimuli. Specific sensors recognize cytoplasmic mtDNA to promote cytokine production. Cytoplasmic mtDNA can also be secreted extracellularly, leading to sterile inflammation. However, the mode of secretion of mtDNA out of cells upon noxious stimuli and its relevance to human disease remain unclear. Here, we show that pyroptotic cells secrete mtDNA encapsulated within exosomes. Activation of caspase-1 leads to mtDNA leakage from the mitochondria into the cytoplasm via gasdermin-D. Caspase-1 also induces intraluminal membrane vesicle formation, allowing for cellular mtDNA to be taken up and secreted as exosomes. Encapsulation of mtDNA within exosomes promotes a strong inflammatory response that is ameliorated upon exosome biosynthesis inhibition in vivo. We further show that monocytes derived from patients with Behçet's syndrome (BS), a chronic systemic inflammatory disorder, show enhanced caspase-1 activation, leading to exosome-mediated mtDNA secretion and similar inflammation pathology as seen in BS patients. Collectively, our findings support that mtDNA-containing exosomes promote inflammation, providing new insights into the propagation and exacerbation of inflammation in human inflammatory diseases.

Discordance of global assessment between the patients and physicians predicts 9-year pain-related outcomes in rheumatoid arthritis patients.

Introduction: Perspectives regarding the disease state often differ between patients with rheumatoid arthritis (RA) and physicians. The aim of the present longitudinal cohort study was to investigate the impact of the discordance in global assessments between patients and physicians on 9-year pain-related outcomes in patients with rheumatoid arthritis. Method: Sixty-eight consecutive outpatients with rheumatoid arthritis on their first visit to a tertiary center were included. Baseline measurements included demographic data, drugs used, disease activity, and a modified Health Assessment Questionnaire (mHAQ). Discordance in global assessment between patients and physicians at baseline was defined as 10 mm higher in the patient global assessment (PGA) than in the physician global assessment. A 9-year follow-up assessment included pain intensity, the European Quality of Life 5 Dimensions 3 Level (EQ-5D-3L) scale, Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS), Pain Disability Assessment Scale (PDAS), and Pain Self-Efficacy Questionnaire (PSEQ). Results: The number of patients with discordance was 26 (38%) in 68 patients. Patients with a 10 mm higher PGA than the physician global assessment at baseline measurements had significantly worse pain intensity, PCS score, PSEQ score, and EQ-5D-3L score measurements at the 9-year follow-up than those with concordance. A higher mHAQ score and 10 mm higher PGA at baseline were significantly independently associated with the EQ-5D-3L scale score and pain intensity at the 9-year follow-up. Conclusion: This longitudinal cohort study suggested that discordance in global assessment between patients and physicians modestly predicted worse 9-year pain-related outcomes in patients with rheumatoid arthritis.

The Ragulator complex: delving its multifunctional impact on metabolism and beyond.

Our understanding of lysosomes has undergone a significant transformation in recent years, from the view that they are static organelles primarily responsible for the disposal and recycling of cellular waste to their recognition as highly dynamic structures. Current research posits that lysosomes function as a signaling hub that integrates both extracellular and intracellular stimuli, thereby regulating cellular homeostasis. The dysregulation of lysosomal function has been linked to a wide range of diseases. Of note, lysosomes contribute to the activation of mammalian target of rapamycin complex 1 (mTORC1), a key regulator of cellular metabolism. The Ragulator complex, a protein complex anchored on the lysosomal membrane, was initially shown to tether the mTORC1 complex to lysosomes. Recent research has substantially expanded our understanding of the roles of the Ragulator complex in lysosomes, including roles in the regulation of metabolism, inflammation, cell death, cell migration, and the maintenance of homeostasis, via interactions with various proteins. This review summarizes our current knowledge on the diverse functions of the Ragulator complex, highlighting important protein interactions.

The Onset of IgG4-related Retroperitoneal Fibrosis under Administration of a TNF Inhibitor in a Rheumatoid Arthritis Patient.

An 80-year-old woman with rheumatoid arthritis during treatment with etanercept, a tumor necrosis factor (TNF) inhibitor, showed swelling of the salivary glands and retroperitoneal fibrosis, which was diagnosed as IgG4-related disease. Although some reports have shown the efficacy of TNF inhibitors for IgG4-related disease or retroperitoneal fibrosis, TNF inhibitors sometimes cause paradoxical reactions like psoriasis, and the mechanisms are considered to involve the upregulation of plasmacytoid dendritic cells and IFN-α, which is also common in patients with IgG4-related disease. This is a case report of IgG4-related retroperitoneal fibrosis with the possibility of a rare paradoxical reaction by a TNF inhibitor.

The lysosomal Ragulator complex activates NLRP3 inflammasome in vivo via HDAC6.

The cellular activation of the NLRP3 inflammasome is spatiotemporally orchestrated by various organelles, but whether lysosomes contribute to this process remains unclear. Here, we show the vital role of the lysosomal membrane-tethered Ragulator complex in NLRP3 inflammasome activation. Deficiency of Lamtor1, an essential component of the Ragulator complex, abrogated NLRP3 inflammasome activation in murine macrophages and human monocytic cells. Myeloid-specific Lamtor1-deficient mice showed marked attenuation of NLRP3-associated inflammatory disease severity, including LPS-induced sepsis, alum-induced peritonitis, and monosodium urate (MSU)-induced arthritis. Mechanistically, Lamtor1 interacted with both NLRP3 and histone deacetylase 6 (HDAC6). HDAC6 enhances the interaction between Lamtor1 and NLRP3, resulting in NLRP3 inflammasome activation. DL-all-rac-α-tocopherol, a synthetic form of vitamin E, inhibited the Lamtor1-HDAC6 interaction, resulting in diminished NLRP3 inflammasome activation. Further, DL-all-rac-α-tocopherol alleviated acute gouty arthritis and MSU-induced peritonitis. These results provide novel insights into the role of lysosomes in the activation of NLRP3 inflammasomes by the Ragulator complex.

SLE stratification based on BAFF and IFN-I bioactivity for biologics and implications of BAFF produced by glomeruli in lupus nephritis.

OBJECTIVE: B-cell activating factor (BAFF) is implicated in SLE pathogenesis. Blocking BAFF signalling has contributed to reducing glucocorticoid dosage and preventing organ damage. However, clinical characteristics of patients who may benefit from this therapy are not yet fully elucidated. Therefore, we identified patients with high BAFF-bioactivity to investigate their clinical characteristics and BAFF-producing cells. METHODS: We established the reporter cell for BAFF and investigated the clinical characteristics of SLE patients with high BAFF-bioactivity. We identified BAFF-expressing kidney cells using publicly available scRNA-seq data and immunohistological analysis. SLE patients were stratified based on the bioactivity of BAFF and type-I IFN (IFN-I) to identify associated characteristic clinical manifestations. RESULTS: SLE patients, especially patients with LN, had significantly higher serum BAFF-bioactivity than healthy controls (HC) and non-LN patients. Additionally, single-cell-RNA-seq data and immunohistological analysis of kidney samples from LN patients revealed that BAFF is expressed in glomerular macrophages and mesangial cells. Notably, BAFF bioactivity was elevated in the urine of LN patients compared with that of non-LN patients, while no IFN-I bioactivity was detected in the urine. Furthermore, SLE stratification based on bioactivities of serum BAFF and IFN-I revealed the clinical characteristics of patients: high BAFF represented patients with LN and high IFN-I represented patients with blood and skin manifestations. CONCLUSIONS: Monitoring urinary BAFF-bioactivity may be valuable in diagnosing LN. Furthermore, stratification based on serum BAFF and IFN-I bioactivities may allow the identification of appropriate patients for biologics targeting BAFF and IFN-I.

The lysosomal Ragulator complex plays an essential role in leukocyte trafficking by activating myosin II.

Lysosomes are involved in nutrient sensing via the mechanistic target of rapamycin complex 1 (mTORC1). mTORC1 is tethered to lysosomes by the Ragulator complex, a heteropentamer in which Lamtor1 wraps around Lamtor2-5. Although the Ragulator complex is required for cell migration, the mechanisms by which it participates in cell motility remain unknown. Here, we show that lysosomes move to the uropod in motile cells, providing the platform where Lamtor1 interacts with the myosin phosphatase Rho-interacting protein (MPRIP) independently of mTORC1 and interferes with the interaction between MPRIP and MYPT1, a subunit of myosin light chain phosphatase (MLCP), thereby increasing myosin II-mediated actomyosin contraction. Additionally, formation of the complete Ragulator complex is required for leukocyte migration and pathophysiological immune responses. Together, our findings demonstrate that the lysosomal Ragulator complex plays an essential role in leukocyte migration by activating myosin II through interacting with MPRIP.

Presepsin and procalcitonin as biomarkers of systemic bacterial infection in patients with rheumatoid arthritis.

AIM: To assess the diagnostic values of presepsin and procalcitonin in patients with rheumatoid arthritis (RA) by identifying those with bacterial infection METHOD: During June 2014-September 2015, 126 patients with RA and 25 healthy controls were enrolled. RA patients were divided into an infection group and a non-infection group. Infection was diagnosed by clinical symptoms, microbiological or radiographic methods, and good response to antibiotics. Concentrations of plasma presepsin, serum procalcitonin, C-reactive protein (CRP), and white blood cell counts (WBC) were measured and compared in each group. The correlations with the Sequential Organ Failure Assessment (SOFA) Score and these markers were calculated. RESULTS: RA patients included 26 patients in the infection group, 45 patients in the CRP-positive non-infection group (CRP > 0.3 mg/dL), and 55 patients in the CRP-negative non-infection group (CRP < 0.3 mg/dL). Levels of presepsin and procalcitonin in the infection group were highest and significantly higher than those in the CRP-positive non-infection group (presepsin 682.8 ± 158.1 pg/mL vs. 192.0 ± 12.0 pg/mL [P < 0.0001]; procalcitonin 4.052 ± 1.637 ng/mL vs. 0.120 ± 0.032 ng/mL [(P < 0.0001]). According to receiver operating characteristic curve (ROC) analysis, presepsin and procalcitonin levels appeared to have a higher diagnostic accuracy for infection than CRP or WBC. For the infection group, the SOFA Score positively correlated with the concentration of presepsin but not with that of procalcitonin. CONCLUSION: Presepsin and procalcitonin may be useful to identify infection in RA patients. Presepsin may better reflect infection severity than procalcitonin.

Atypical Presenting Symptoms of Acute Onset Systemic Lupus Erythematosus with Enteritis and Cystitis.

Lupus enteritis and lupus cystitis are relatively rare manifestations of systemic lupus erythematosus. Some patients develop severe complications such as bowel perforation, infarction, obstruction, or irreversible bladder dysfunction. Early diagnosis is critical for management of lupus enteritis and cystitis. We report a 48-year-old Japanese man who presented with initial manifestations of abdominal pain, severe diarrhea, and bloody feces. The diagnosis was delayed due to atypical initial symptoms, resulting in clinical worsening. Physicians should be aware of typical computed tomography findings of lupus enteritis and lupus cystitis.

Successful Use of Plasma Exchange in the Treatment of Corticosteroid-Refractory Eosinophilic Granulomatosis with Polyangiitis Associated with Gastrointestinal Manifestations.

We describe the case of a 33-year-old woman having corticosteroid-refractory eosinophilic granulomatosis with polyangiitis (EGPA) who presented with abdominal pain and responded dramatically to plasma exchange. Eosinophilia, asthma history, neuropathy, pulmonary infiltrates, and paranasal sinus abnormalities confirmed the diagnosis of EGPA. Treatment was initiated with 1 g/day of methylprednisolone pulse therapy for 3 days followed by 60 mg/day of intravenous prednisolone without relieving abdominal pain. Then, plasma exchange was performed thrice. Abdominal pain disappeared after the first plasma exchange. Indication of plasma exchange for EGPA remains controversial; however, it may represent a valid option in cases with gastrointestinal involvement.

[Brain abscess mediated through a pulmonary arteriovenous malformation in a patient with hereditary hemorrhagic telangiectasia].

The patient is a 66-year-old man with hereditary telangiectasia. He was diagnosed with pulmonary arteriovenous malformation (PAVM), which was revealed by contrast-enhanced chest computed tomography at the age of 65. He developed headache, right homonymous hemianopsia, and right hemiparesis and was admitted to our hospital. Contrast-enhanced magnetic resonance imaging revealed multiple lesions in the left hemisphere, which indicates brain abscesses. Thus, the diagnosis of brain abscess mediated through PAVM was established. Following management with drainage and coil embolization, all neurological symptoms resolved. Therefore, coil embolization should be considered for PAVM at an early stage to prevent brain abscess, even if it is asymptomatic.