The oxidative phosphorylation inhibitor IM156 suppresses B-cell activation by regulating mitochondrial membrane potential and contributes to the mitigation of systemic lupus erythematosus.

Current treatment strategies for autoimmune diseases may not sufficiently control aberrant metabolism in B-cells. To address this concern, we investigated a biguanide derivative, IM156, as a potential regulator for B-cell metabolism in vitro and in vivo on overactive B-cells stimulated by the pro-inflammatory receptor TLR-9 agonist CpG oligodeoxynucleotide, a mimic of viral/bacterial DNA. Using RNA sequencing, we analyzed the B-cell transcriptome expression, identifying the major molecular pathways affected by IM156 in vivo. We also evaluated the anti-inflammatory effects of IM156 in lupus-prone NZB/W F1 mice. CD19+B-cells exhibited higher mitochondrial mass and mitochondrial membrane potential compared to T-cells and were more susceptible to IM156-mediated oxidative phosphorylation inhibition. In vivo, IM156 inhibited mitochondrial oxidative phosphorylation, cell cycle progression, plasmablast differentiation, and activation marker levels in CpG oligodeoxynucleotide-stimulated mouse spleen B-cells. Interestingly, IM156 treatment significantly increased overall survival, reduced glomerulonephritis and inhibited B-cell activation in the NZB/W F1 mice. Thus, our data indicated that IM156 suppressed the mitochondrial membrane potentials of activated B-cells in mice, contributing to the mitigation of lupus activity. Hence, IM156 may represent a therapeutic alternative for autoimmune disease mediated by B-cell hyperactivity.

Mitochondria Activity and CXCR4 Collaboratively Promote the Differentiation of CD11c+ B Cells Induced by TLR9 in Lupus.

Lupus is characterized by the autoantibodies against nuclear Ags, underscoring the importance of identifying the B cell subsets driving autoimmunity. Our research focused on the mitochondrial activity and CXCR4 expression in CD11c+ B cells from lupus patients after ex vivo stimulation with a TLR9 agonist, CpG-oligodeoxyribonucleotide (ODN). We also evaluated the response of CD11c+ B cells in ODN-injected mice. Post-ex vivo ODN stimulation, we observed an increase in the proportion of CD11chi cells, with elevated mitochondrial activity and CXCR4 expression in CD11c+ B cells from lupus patients. In vivo experiments showed similar patterns, with TLR9 stimulation enhancing mitochondrial and CXCR4 activities in CD11chi B cells, leading to the generation of anti-dsDNA plasmablasts. The CXCR4 inhibitor AMD3100 and the mitochondrial complex I inhibitor IM156 significantly reduced the proportion of CD11c+ B cells and autoreactive plasmablasts. These results underscore the pivotal roles of mitochondria and CXCR4 in the production of autoreactive plasmablasts.

Decreased ex vivo production of interferon-gamma is associated with severity and poor prognosis in patients with lupus.

BACKGROUND: Lupus pathogenesis is closely associated with interferon gamma (IFN-γ), which plays a central role in innate and adaptive immunity. The aim of this study was to evaluate the ex vivo production of IFN-γ after stimulation of peripheral blood mononuclear cells with phytohemagglutinin (PHA) in patients with lupus, according to disease activity. METHODS: This study included 118 patients with lupus who had undergone IFN-γ-releasing assays (IGRAs) to screen for tuberculosis. Data on IFN-γ production in negative (nil) and positive (mitogen with PHA) controls were collected and analysed. The difference (mitogen minus nil) was used to calculate ex vivo IFN-γ production. Disease activity was evaluated using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K). Poor hospitalisation outcome was defined as in-hospital mortality or intensive care unit admission. Associations among disease activity, poor hospitalisation outcome, and ex vivo IFN-γ production were assessed. RESULTS: The level of ex vivo IFN-γ production was significantly lower in patients with active systemic lupus erythematosus (SLE) (n = 64) than in those with inactive SLE (n = 54) (median 0.92 vs. 11.06 IU/mL, p < 0.001). Ex vivo IFN-γ production was correlated with the SLEDAI-2 K (r = - 0.587, p < 0.001). Results of multivariate logistic regression analysis showed that ex vivo IFN-γ production ≤ 7.19 IU/mL was an independent predictor for discriminating active and inactive lupus. In addition, patients with ex vivo IFN-γ production ≤ 0.40 IU/mL had more frequent poor hospitalisation outcomes than those with ex vivo IFN-γ production > 0.40 (40.0% vs. 9.3%, p = 0.001). The proportion of indeterminate IGRA results was higher in patients with active lupus than in those with inactive lupus (45.3% vs. 0.0%, p < 0.001) because of decreased ex vivo IFN-γ production. CONCLUSIONS: Ex vivo IFN-γ production is a useful biomarker for assessing disease activity and predicting poor clinical outcomes of SLE.

Neutrophil extracellular traps (NETs) in autoimmune diseases: A comprehensive review.

Neutrophil extracellular traps (NETs) are fibrous networks which protrude from the membranes of activated neutrophils. NETs are found in a variety of conditions such as infection, malignancy, atherosclerosis, and autoimmune diseases including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV), psoriasis, and gout. Studies suggest that an imbalance between "NETosis," which is a process by which NETs are formed, and NET degradation may be associated with autoimmune diseases. Neutrophils, interleukin-8, ANCA and other inflammatory molecules are considered to play a key role in NET formation. Prolonged exposure to NETs-related cascades is associated with autoimmunity and increases the chance of systemic organ damage. In this review, we discuss the roles of various inflammatory molecules in relation to NETs. We also describe the role of NETs in the pathogenesis of autoimmune diseases and discuss the possibility of using targeted therapies directed to NETs and associated molecules to treat autoimmune diseases.