Type I interferons affect the metabolic fitness of CD8+ T cells from patients with systemic lupus erythematosus

Oral ENPP1 inhibitor designed using generative AI as next generation STING modulator for solid tumors

Despite the STING-type-I interferon pathway playing a key role in effective anti-tumor immunity, the therapeutic benefit of direct STING agonists appears limited. In this study, we use several artificial intelligence techniques and patient-based multi-omics data to show that Ectonucleotide Pyrophosphatase/Phosphodiesterase 1 (ENPP1), which hydrolyzes STING-activating cyclic GMP-AMP (cGAMP), is a safer and more effective STING-modulating target than direct STING agonism in multiple solid tumors. We then leverage our generative chemistry artificial intelligence-based drug design platform to facilitate the design of ISM5939, an orally bioavailable ENPP1-selective inhibitor capable of stabilizing extracellular cGAMP and activating bystander antigen-presenting cells without inducing either toxic inflammatory cytokine release or tumor-infiltrating T-cell death. In murine syngeneic models across cancer types, ISM5939 synergizes with targeting the PD-1/PD-L1 axis and chemotherapy in suppressing tumor growth with good tolerance. Our findings provide evidence supporting ENPP1 as an innate immune checkpoint across solid tumors and reports an AI design-aided ENPP1 inhibitor, ISM5939, as a cutting-edge STING modulator for cancer therapy, paving a path for immunotherapy advancements.

Viperin expression leads to downregulation of mitochondrial genes through misincorporation of ddhCTP by mitochondrial RNA polymerase

Increasing lines of evidence link the expression of the interferon-stimulated gene RSAD2, encoding the antiviral enzyme, viperin, to autoimmune disease. Autoimmune diseases are characterized by chronic overproduction of cytokines such as interferons that upregulate the inflammatory response. Immune cells exposed to interferon selectively downregulate transcription of the mitochondrially encoded components of the oxidative phosphorylation system, which leads to mitochondria becoming dysfunctional and impairing their ability to produce ATP. But the mechanism by which downregulation occurs has remained unknown. Here we show that 3'-deoxy-3',4'-didehydrocytidine triphosphate (ddhCTP) which is synthesized by viperin suppresses mitochondrial transcription by causing premature chain termination when misincorporated by the mitochondrial RNA polymerase (POLRMT). We show that viperin expression in human cell lines downregulates mitochondrially encoded gene expression. A similar effect is observed across multiple cell lines when cells are exposed to ddhC, the precursor to ddhCTP. The pattern of gene downregulation fits well with a simple, quantitative model describing chain-termination. In vitro measurements with purified POLRMT demonstrate that ddhCTP competes effectively with CTP, leading to its misincorporation into RNA. These findings reveal a new molecular mechanism for mitochondrial transcriptional regulation that explains the reduction in mitochondrially-encoded transcript levels in response to chronic interferon stimulation, characteristic of inflammatory diseases.

Recent Advances of Type I Interferon on the Regulation of Immune Cells and the Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with multiple organ damage. Several studies have found that, in addition to significant production of autoantibodies, the majority of SLE patients exhibit increased expression of type I interferon (IFN-I) regulated genes (also known as IFN-I traits), and that IFN-I plays a crucial role in the pathogenesis of SLE. In SLE, virtually all immune cells are dysregulated, and most of these aberrant dysregulations are directly or indirectly affected by IFN-I. The mechanism of action of IFN-I in these immune cells is multifaceted. In this review, we focus on the immune cell types that produce IFN-I and are affected by IFN-I in SLE. Importantly, we explore the research progress of related drugs in terms of IFN-I production, itself, and downstream. Here we provide the most up-to-date information on the mechanisms that lead to the pathogenesis of SLE, providing the basis for the development of innovative future therapies and future research directions.

Identification and immunoassay of biomarkers associated with T cell exhaustion in systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease with unclear etiology. T cell exhaustion (TEX) suppresses the immune response and can be a potential therapeutic strategy for autoimmune diseases. Therefore, this study primarily investigated the mechanism by which TEX influences SLE, offering a novel target for its treatment.

Methods

GSE72326 and GSE81622 were utilized in this study. TEX related genes (TEX-RGs) were obtained from the published literature. Differentially expressed genes (DEGs) were obtained through differential expression analysis. Subsequently, candidate genes were selected by overlapping DEGs and TEX-RGs. These candidate genes underwent protein-protein interactions (PPIs) analysis for further screening. Machine learning was applied to identify candidate key genes from the PPI-identified genes. The candidate key genes exhibiting an area under the receiver operating characteristic (ROC) curve (AUC) greater than 0.7, along with consistent expression trends and significant differences in GSE72326 and GSE81622 were defined as biomarkers. Additionally, enrichment analysis, immune infiltration analysis, chemical compounds prediction and molecular docking were carried out. Importantly, the biomarkers were validated for expression by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

Results

The biomarkers MX1, LY6E, IFI44 and OASL were screened by overlapping 327 DEGs and 1,408 TEX-RGs. Gene set enrichment analysis (GSEA) showed that there was a significant positive correlation between the expression of these biomarkers and immune-related pathways, such as the NOD-like receptor signaling pathway, Toll-like receptor signaling pathway and RIG-I-like receptor signaling pathway significant positive correlation. The immune infiltration of 8 types of immune cells differed significantly in SLE. Naive B cells, resting memory CD4 T cells and resting NK cells were significantly down-regulated in the SLE group. 4 biomarkers showed the highest correlation with resting memory CD4 T cells. Bisphenol A targeted OASL and LY6E, whereas acetaminophen targeted IFI44 and MX1.The binding activity between the biomarkers and the chemical compounds targeting them was very strong. Finally, RT-qPCR expression of MX1, LY6E, IFI44 and OASL was consistent with the results of the dataset.

Conclusion

MX1, LY6E, IFI44 and OASL were identified as biomarkers related to TEX in SLE. These biomarkers could be detected in the blood for early diagnosis of the disease or to monitor the efficacy of the disease treatment, thus providing a new target for the management of SLE.

Induction of LY6E regulates interleukin-1β production, potentially contributing to the immunopathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by the deposition of immune complexes (ICs) in various organs, especially the kidney, leading to lupus nephritis, one of the major and therapeutically challenging manifestations of SLE. Among the various cytokines induced in SLE, type I interferons (IFN-Is) play crucial roles in mediating immunopathogenesis, and anti-IFN-I treatment has been approved for SLE treatment. The uptake of ICs by macrophages results in macrophage activation, which initiates, triggers, and exaggerates immune responses in SLE. After observing the induction of an IFN-stimulated gene, LY6E, in monocytes from SLE patients, we demonstrated the colocalization of both LY6E and a macrophage marker in kidneys from pristane-induced lupus-prone mice and from patients with lupus nephritis. By studying mouse bone marrow-derived macrophages, we showed that LY6E regulated IFN-α- and IC-induced production and secretion of mature interleukin-1β (mIL-1β), foam cell formation and several mitochondria-associated mechanisms, such as the release of mitochondrial DNA (mtDNA) but not mitochondrial RNA (mtRNA) into the cytosol, the generation of mitochondrial reactive oxygen species (mtROS) and ROS, the activation of caspase 1, NLRP3, and the stimulator of interferon genes (STING) signaling pathway, and the activation of cytidine/uridine monophosphate kinase 2 (CMPK2), which were involved in LY6E-mediated immunomodulatory effects. In addition, synergistic effects of a combination of IL-1β and IFN-α and of IL-1β and ICs on the induction of the expression of IFN-stimulated genes were observed. In addition to revealing the proinflammatory roles and mechanisms of LY6E in macrophages, given that various subgroups of macrophages have been identified in the kidneys of patients with lupus nephritis, targeted treatment aimed at LY6E may be a potential therapeutic for lupus nephritis.

Machine learning-driven immunophenotypic stratification of mixed connective tissue disease, corroborating the clinical heterogeneity

OBJECTIVE

The objective of this study was to stratify patients with MCTD, based on their immunophenotype.

METHODS

We analysed the immunophenotype and transcriptome of 24 immune cell subsets [from patients with MCTD, SLE, idiopathic inflammatory myopathy (IIM) and SSc] from our functional genome database, ImmuNexUT (https://www.immunexut.org/). MCTD patients were stratified by employing machine-learning models, including Random Forest, trained by immunophenotyping data from SLE, IIM and SSc patients. The transcriptomes were analysed with gene set variation analysis (GSVA), and the clinical features of the MCTD subgroups were compared.

RESULTS

This study included 215 patients, including 22 patients with MCTD. Machine-learning models, constructed to classify SLE, IIM and SSc patients, based on immunophenotyping, were applied to MCTD patients, resulting in 16 patients being classified as having an SLEimmunophenotype and 6 as having a non-SLE immunophenotype. Among the MCTD patients, patients with the SLE immunophenotype had higher proportions of Th1 cells {2.85% [interquartile range (IQR) 1.54-3.91] vs 1.33% (IQR 0.99-1.74) P = 0.027} and plasmablasts [6.35% (IQR 4.17-17.49) vs 2.00% (IQR 1.20-2.80) P = 0.010]. Notably, the number of SLE-related symptoms was higher in patients with the SLE immunophenotype [2.0 (IQR 1.0-2.0) vs 1.0 (IQR 1.0-1.0) P = 0.038]. Moreover, the GSVA scores of interferon-α and -γ responses were significantly higher in patients with the SLE immunophenotype in central memory CD8+ T cells, while hedgehog signalling was higher in patients with the non-SLE immunophenotype, in five-cell subsets.

CONCLUSION

This study describes the stratification of MCTD patients, based on immunophenotyping, suggesting the presence of distinct immunological processes behind the clinical subtypes of MCTD.

Immunometabolic shifts in autoimmune disease: Mechanisms and pathophysiological implications

Autoimmune diseases occur when the immune system abnormally attacks the body's normal tissues, causing inflammation and damage. Each disease has unique immune and metabolic dysfunctions during pathogenesis. In rheumatoid arthritis (RA), immune cells have different metabolic patterns and mitochondrial/lysosomal dysfunctions at different disease stages. In systemic lupus erythematosus (SLE), type I interferon (IFN) causes immune cell metabolic dysregulation, linking activation to metabolic shifts that may worsen the disease. In systemic sclerosis (SSc), mitochondrial changes affect fibroblast metabolism and the immune response. Idiopathic inflammatory myopathies (IIMs) patients have mitochondrial and metabolic issues. In primary Sjögren's syndrome (pSS), immune cell metabolism is imbalanced and mitochondrial damage can lead to cell/tissue damage. Metabolic reprogramming links cellular energy needs and immune dysfunctions, causing inflammation, damage, and symptoms in these diseases. It also affects immune cell functions like differentiation, proliferation, and secretion. This review discusses the potential of targeting metabolic pathways to restore immune balance, offering directions for future autoimmune disease research and treatment.

Association of peripheral CD8+ T cell activation with disease activity and treatment resistance in systemic lupus erythematosus

OBJECTIVE

Various immune-cell subsets intricately mediate the pathogenesis of systemic lupus erythematosus (SLE). However, the role of CD8+ T cells in SLE remains unclear. We investigated the proportions and characteristics of peripheral CD8+ T cells and their association with clinical manifestations of SLE.

METHODS

We retrospectively enrolled 211 patients with SLE and 48 age- and sex-matched healthy controls (HCs). Peripheral CD8+ T cells were analysed using flow cytometry. The primary endpoint was the comparison of peripheral CD8+ T cell subset characteristics between patients and HCs.

RESULTS

Patients with SLE (mean age, 42.3 years; women, 89% and mean disease duration, 112.8 months) had significantly higher proportions of naïve CD8+ T cells (CCR7+CD45RA+), CD8+ terminally differentiated effector memory cells (CCR7-CD45RA+) and activated CD8+ T cells (CD38+HLA-DR+) in peripheral blood mononuclear cells than HCs (p<0.001). Activated CD8 + T cells produced granzyme B and interferon-γ, which correlated with serum double-stranded (ds) DNA antibodies (rs=0.3146, p<0.0001) and 50% haemolytic unit of complement (rs=-0.3215, p=0.0003), and were significantly increased in patients with active systemic, renal or haematological involvement (p<0.05). Cluster analysis-based subgroup classification based on CD8 cell differentiation and activation revealed a group with high numbers of activated CD8+ T cells, highly active SLE and organ damage, including active nephritis and persistently high cell counts after a 24-week treatment, indicating treatment resistance (high anti-dsDNA antibody titres and high glucocorticoid doses).

CONCLUSION

In SLE, greater proportions of highly cytotoxic and proinflammatory activated CD8+ T cells in peripheral blood-modulated disease activity, organ damage and residual treatment resistance, presenting a potential treatment target.

Epigenetic mechanisms regulating CD8+ T cell senescence in aging humans

Aging leads to the decline of immunity, rendering the elderly susceptible to infection and disease. In the CD8+ T cell compartment, aging leads to a substantial increase of cells with high levels of senescence-associated ß-galactosidase activity (SA-ßGal) and other senescence characteristics, including a pro-inflammatory transcriptome and impaired proliferative potential. Using senescent cell isolation coupled with multiomic profiling, here we characterized the epigenetic mechanisms regulating CD8+ T cell senescence in a cohort of younger and older donors. High levels of SA-ßGal activity defined changes to global transcriptomes and chromatin accessibility landscapes, with a minor effect of age. Widespread enhancer remodeling was required for the repression of functional CD8+ T cell genes and upregulation of inflammatory and secretory pathway genes. Mechanistically, the senescence program in CD8+ T cells was controlled by chromatin state-specific transcription factor (TF) networks whose composition was largely insensitive to donor age. Pharmacological inhibition of TF network nodes AP1, KLF5, and RUNX2 modulated the transcriptional output, demonstrating the feasibility of TF network perturbation as an approach to modulate CD8+ T cell senescence. Further, CD8+ T cell senescence gene signatures faithfully predicted refractoriness to chimeric antigen receptor (CAR) T-cell therapy in a cohort of diffuse large B cell lymphomas and were highly enriched in the transcriptomes of peripheral CD8+ T cells of individuals with active systemic lupus erythematosus. Collectively, our findings demonstrate the potential of multiomic profiling in identifying key regulators of senescence across cell types and suggest a critical role of senescent CD8+ T cells in disease progression.

Type I interferon and mitochondrial dysfunction are associated with dysregulated cytotoxic CD8+ T cell responses in juvenile systemic lupus erythematosus

Juvenile systemic lupus erythematosus (JSLE) is an autoimmune condition which causes significant morbidity in children and young adults and is more severe in its presentation than adult-onset SLE. While many aspects of immune dysfunction have been studied extensively in adult-onset SLE, there is limited and contradictory evidence of how cytotoxic CD8+ T cells contribute to disease pathogenesis and studies exploring cytotoxicity in JSLE are virtually non-existent. Here, we report that CD8+ T cell cytotoxic capacity is reduced in JSLE versus healthy controls, irrespective of treatment or disease activity. Transcriptomic and serum metabolomic analysis identified that this reduction in cytotoxic CD8+ T cells in JSLE was associated with upregulated type I interferon (IFN) signalling, mitochondrial dysfunction, and metabolic disturbances when compared to controls. Greater interrogation of the influence of these pathways on altered cytotoxic CD8+ T cell function demonstrated that JSLE CD8+ T cells had enlarged mitochondria and enhanced sensitivity to IFN-α leading to selective apoptosis of effector memory (EM) CD8+ T cells, which are enriched for cytotoxic mediator-expressing cells. This process ultimately contributes to the observed reduction in CD8+ T cell cytotoxicity in JSLE, reinforcing the growing evidence that mitochondrial dysfunction is a key pathogenic factor affecting multiple immune cell populations in type I IFN-driven rheumatic diseases.

Evaluating the Causal Association between Circulating Plasma Proteins, 731 Immune Cell Phenotypes, and Atopic Dermatitis: A Mediation Mendelian Randomization Study

INTRODUCTION

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by eczematous lesions and severe itching. However, its pathogenesis has not yet been fully elucidated. The aim of this study was to investigate the causal relationship between plasma proteins and AD, as well as to identify and quantify the potential roles of immune cell phenotypes as mediators.

METHODS

We utilized summary-level data from genome-wide association studies and conducted a two-sample Mendelian randomization (MR) analysis involving 4,907 circulating plasma proteins, 731 immune cell phenotypes, and AD. Initially, we conducted bidirectional univariate MR analyses to forecast causal effects linking circulating plasma proteins and AD. Subsequently, we employed a two-step MR analysis to scrutinize the immune cell phenotypes that could mediate these effects. The inverse variance weighted was the main method employed for MR analysis, while the Cochran's Q test and MR-Egger intercept test were used to assess the presence of heterogeneity and pleiotropy, respectively. We then determined whether our results could be influenced by individual single-nucleotide polymorphisms using the "leave-one-out" test.

RESULTS

Positive correlations were observed between KRT1, IL18R1, and SEMA6A and the risk of AD, whereas BDH2, ADAMTS3, ANKRD1, TIAM1, MID2, and IFNA16 all showed negative correlations with the risk of AD. Mediation analysis indicated that CD8 on CM CD8br cells acted as a mediator between IFNA16 and AD, with a mediation effect proportion of 11.2%. In addition, sensitivity analyses did not reveal significant heterogeneity or level pleiotropy.

CONCLUSION

Our findings indicated the presence of a one-way causal relationship between the circulating plasma protein IFNA16 and AD. This study also explored immune cell phenotypes that may serve as mediators, offering novel insights into the etiology, pathogenesis, and potential clinical interventions in AD. Nevertheless, these findings need to be validated by clinical and laboratory studies.

The role of TNF-α as a potential marker for acute cutaneous lupus erythematosus in patients with systemic lupus erythematosus

Acute cutaneous lupus erythematosus (ACLE) is closely associated with systemic symptoms in systemic lupus erythematosus (SLE). This study aimed to identify potential biomarkers for ACLE and explore their association with SLE to enable early prediction of ACLE and identify potential treatment targets for the future. In total, 185 SLE-diagnosed patients were enrolled and categorized into two groups: those with ACLE and those without cutaneous involvement. After conducting logistic regression analysis of the differentiating factors, we concluded that tumor necrosis factor-alpha (TNF-α) is an independent risk factor for ACLE. Analysis of the receiver operating characteristic revealed an area under the curve of 0.716 for TNF-α. Additionally, both TNF-α and ACLE are positively correlated with disease activity. TNF-α shows promise as a biomarker for ACLE, and in SLE patients, ACLE may serve as a clear indicator of moderate-to-severe disease activity.

Blood RNA-sequencing across the continuum of ANA-positive autoimmunity reveals insights into initiating immunopathology

OBJECTIVE

Mechanisms underpinning clinical evolution to systemic lupus erythematosus (SLE) from preceding antinuclear antibodies (ANA) positivity are poorly understood. This study aimed to understand blood immune cell transcriptional signatures associated with subclinical ANA positivity, and progression or non-progression to SLE.

METHODS

Bulk RNA-sequencing of peripheral blood mononuclear cells isolated at baseline from 35 ANA positive (ANA+) subjects with non-diagnostic symptoms was analysed using differential gene expression, weighted gene co-expression network analysis, deconvolution of cell subsets and functional enrichment analyses. ANA+ subjects, including those progressing to classifiable SLE at 12 months (n=15) and those with stable subclinical ANA positivity (n=20), were compared with 15 healthy subjects and 18 patients with SLE.

RESULTS

ANA+ subjects demonstrated extensive transcriptomic dysregulation compared with healthy controls with reduced CD4+naïve T-cells and resting NK cells, but higher activated dendritic cells. B-cell lymphopenia was evident in SLE but not ANA+ subjects. Two-thirds of dysregulated genes were common to ANA+ progressors and non-progressors. ANA+ progressors showed elevated modular interferon signature in which constituent genes were inducible by both type I interferon (IFN-I) and type II interferon (IFN-II) in vitro. Baseline downregulation of mitochondrial oxidative phosphorylation complex I components significantly associated with progression to SLE but did not directly correlate with IFN modular activity. Non-progressors demonstrated more diverse cytokine profiles.

CONCLUSIONS

ANA positivity, irrespective of clinical trajectory, is profoundly dysregulated and transcriptomically closer to SLE than to healthy immune function. Metabolic derangements and IFN-I activation occur early in the ANA+ preclinical phase and associated with diverging transcriptomic profiles which distinguish subsequent clinical evolution.

Pathological mechanisms and crosstalk among various cell death pathways in cardiac involvement of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prevalent autoimmune disease primarily characterized by the involvement of multiple systems and organs. Cardiovascular disease is the primary cause of mortality in patients with SLE, though the mechanisms underlying the increased cardiovascular risk in SLE patients remain unclear. Recent studies indicate that abnormal activation of programmed cell death (PCD) signaling and the crosstalk among various forms of cell death are critical in the immunopathogenesis of SLE. Furthermore, apoptosis, necroptosis, pyroptosis, NETosis, and ferroptosis are recognized as key cellular processes in the pathogenesis of SLE and are closely linked to cardiac involvement. This review uniquely explores the intricate crosstalk between apoptosis, necroptosis, and other cell death pathways, discussing their roles and interactions in the pathogenesis of cardiac involvement in SLE. Investigating the interplay between PCD signaling and cardiac involvement in SLE in understanding the disease's underlying mechanisms and offers opportunities for new therapeutic interventions. The integration of precision medicine and innovative strategies targeting these complex pathways holds promise for enhancing the treatment prospects of SLE with cardiac involvement.

Interferon α and β induce differential transcriptional and functional metabolic phenotypes in human macrophages and blunt glycolysis in response to antigenic stimuli

The impact of chronic exposure to type I interferons (IFN)-α2a, 2b, and β on macrophage metabolism, intimately linked to macrophage function, is not well understood. This study assesses the nuanced host responses induced by type I IFN cytokines, offering insights into potential therapeutic approaches in diseases associated with these cytokines. Employing a combination of transcriptional profiling and real-time functional analysis, we delineated metabolic reprogramming in response to chronic IFN exposure. Our results reveal distinct transcriptional metabolic profiles between macrophages chronically exposed to IFN-α and IFN-β. IFN-β significantly diminishes the oxygen consumption rate and glycolytic proton extrusion rate in macrophages. Conversely, IFN-α2b decreased parameters of mitochondrial fitness and induced a shift toward glutamine oxidation. Assessing the ability of macrophages to induce glycolysis in response to antigenic stimuli (LPS and iH37Rv), we found that chronic exposure to all IFN subtypes limited glycolytic induction. This study addresses a critical oversight in the literature, where individual roles of IFN subtypes are frequently amalgamated and lack distinction. These findings not only provide novel insights into the divergent effects of IFN-α2a, α2b, and β on macrophage metabolism but also highlight their potential implications for developing targeted therapeutic strategies.

Defective mitochondrial COX1 translation due to loss of COX14 function triggers ROS-induced inflammation in mouse liver

Mitochondrial oxidative phosphorylation (OXPHOS) fuels cellular ATP demands. OXPHOS defects lead to severe human disorders with unexplained tissue specific pathologies. Mitochondrial gene expression is essential for OXPHOS biogenesis since core subunits of the complexes are mitochondrial-encoded. COX14 is required for translation of COX1, the central mitochondrial-encoded subunit of complex IV. Here we describe a COX14 mutant mouse corresponding to a patient with complex IV deficiency. COX14M19I mice display broad tissue-specific pathologies. A hallmark phenotype is severe liver inflammation linked to release of mitochondrial RNA into the cytosol sensed by RIG-1 pathway. We find that mitochondrial RNA release is triggered by increased reactive oxygen species production in the deficiency of complex IV. Additionally, we describe a COA3Y72C mouse, affected in an assembly factor that cooperates with COX14 in early COX1 biogenesis, which displays a similar yet milder inflammatory phenotype. Our study provides insight into a link between defective mitochondrial gene expression and tissue-specific inflammation.

Intersection of the microbiome and immune metabolism in lupus

Systemic lupus erythematosus is a complex autoimmune disease resulting from a dysregulation of the immune system that involves gut dysbiosis and an altered host cellular metabolism. This review highlights novel insights and expands on the interactions between the gut microbiome and the host immune metabolism in lupus. Pathobionts, invasive pathogens, and even commensal microbes, when in dysbiosis, can all trigger and modulate immune responses through metabolic reprogramming. Changes in the microbiota's global composition or individual taxa may trigger a cascade of metabolic changes in immune cells that may, in turn, reprogram their functions. Factors contributing to dysbiosis include changes in intestinal hypoxia, competition for glucose, and limited availability of essential nutrients, such as tryptophan and metal ions, all of which can be driven by host metabolism changes. Conversely, the accumulation of some host metabolites, such as itaconate, succinate, and free fatty acids, could further influence the microbial composition and immune responses. Overall, mounting evidence supports a bidirectional relationship between host immunometabolism and the microbiota in lupus pathogenesis.

The PP2A regulatory subunit PPP2R2A controls NAD+ biosynthesis to regulate T cell subset differentiation in systemic autoimmunity

The protein phosphatase 2A (PP2A) regulatory subunit PPP2R2A is involved in the regulation of immune response. We report that lupus-prone mice with T cells deficient in PPP2R2A display less autoimmunity and nephritis. PPP2R2A deficiency promotes NAD+ biosynthesis through the nicotinamide riboside (NR)-directed salvage pathway in T cells. NR inhibits murine Th17 and promotes Treg cell differentiation, in vitro, by PΑRylating histone H1.2 and causing its reduced occupancy in the Foxp3 loci and increased occupancy in the Il17a loci, leading to increased Foxp3 and decreased Il17a transcription. NR treatment suppresses disease in MRL.lpr mice and restores NAD+-dependent poly [ADP-ribose] polymerase 1 (PARP1) activity in CD4 T cells from patients with systemic lupus erythematosus (SLE), while reducing interferon (IFN)-γ and interleukin (IL)-17 production. We conclude that PPP2R2A controls the level of NAD+ through the NR-directed salvage pathway and promotes systemic autoimmunity. Translationally, NR suppresses lupus nephritis in mice and limits the production of proinflammatory cytokines by SLE T cells.

Targeted metabolomics combined with machine learning to identify and validate new biomarkers for early SLE diagnosis and disease activity

BACKGROUND

The early diagnosis of systemic lupus erythematosus (SLE) and the assessment of disease activity progression remain a great challenge. Targeted metabolomics has great potential to identify new biomarkers of SLE.

METHODS

Serum from 44 healthy participants and 89 SLE patients were analyzed using HM400 high-throughput targeted metabolomics. Machine learning (ML) with seven learning models and trained the model several times iteratively selected the two best prediction model in a competitive way, which were independent validated by enzyme-linked immunosorbent (ELISA) with 90 SLE patients.

RESULTS

In this study, 146 differential metabolites, most of them organic acids, amino acids, and bile acids, were detected between patients with initial SLE and healthy participants, and 8 potential biomarkers were found by intersection of ML and statistics (area under the curve [AUC] > 0.95) showing a significant positive correlation with clinical indicators. In addition, we identified and validated 2 potential biomarkers for SLE classification (P < 0.05, AUC > 0.775; N-Methyl-L-glutamic acid, L-2-aminobutyric acid) showing a significant correlation with the SLE Disease Activity Index. These differential metabolites were mainly involved in metabolic pathways, amino acid biosynthesis, 2-oxocarboxylic acid metabolism and other pathways.

CONCLUSION

This study indicated that the tricarboxylic acid cycle might be associated with SLE drug therapy. We identified 8 diagnostic models biomarkers and 2 biomarkers that could be used to identify initial SLE and distinguish different activity degree, which will promote the development of new tools for the diagnosis and evaluation of SLE.

Type I interferon pathway in pediatric systemic lupus erythematosus

BACKGROUND

The role of type I interferon (IFN-I) signaling in systemic lupus erythematosus (SLE) has been well established. However, unanswered questions remain regarding the applicability of these findings to pediatric-onset SLE. The aim of this review is to provide an overview of the novel discoveries on IFN-I signaling in pediatric-onset SLE.

DATA SOURCES

A literature search was conducted in the PubMed database using the following keywords: "pediatric systemic lupus erythematosus" and "type I interferon".

RESULTS

IFN-I signaling is increased in pediatric SLE, largely due to the presence of plasmacytoid dendritic cells and pathways such as cyclic GMP-AMP synthase-stimulator of interferon genes-TANK-binding kinase 1 and Toll-like receptor (TLR)4/TLR9. Neutrophil extracellular traps and oxidative DNA damage further stimulate IFN-I production. Genetic variants in IFN-I-related genes, such as IFN-regulatory factor 5 and tyrosine kinase 2, are linked to SLE susceptibility in pediatric patients. In addition, type I interferonopathies, characterized by sustained IFN-I activation, can mimic SLE symptoms and are thus important to distinguish. Studies on interferonopathies also contribute to exploring the pathogenesis of SLE. Measuring IFN-I activation is crucial for SLE diagnosis and stratification. Both IFN-stimulated gene expression and serum IFN-α2 levels are common indicators. Flow cytometry markers such as CD169 and galectin-9 are promising alternatives. Anti-IFN therapies, such as sifalimumab and anifrolumab, show promise in adult patients with SLE, but their efficacy in pediatric patients requires further investigation. Janus kinase inhibitors are another treatment option for severe pediatric SLE patients.

CONCLUSIONS

This review presents an overview of the IFN-I pathway in pediatric SLE. Understanding the intricate relationship between IFN-I and pediatric SLE may help to identify potential diagnostic markers and targeted therapies, paving the way for improved patient care and outcomes.

Canonical and noncanonical functions of complement in systemic lupus erythematosus

For many years complement activation in systemic lupus erythematosus (SLE) was viewed as a major cause of tissue injury. However, human and murine studies showed that complement plays a protective as well as a proinflammatory role in tissue damage. A hierarchy is apparent with early classical pathway components, particularly C1q, exerting the greatest influence. Understanding the mechanisms underlying the protective function(s) of complement remains an important challenge for the future and has implications for the use of complement therapy in SLE. We review recent advances in the field and give a new perspective on the complement conundrum in SLE.

Active juvenile systemic lupus erythematosus is associated with distinct NK cell transcriptional and phenotypic alterations

While adaptive immune responses have been studied extensively in SLE (systemic lupus erythematosus), there is limited and contradictory evidence regarding the contribution of natural killer (NK) cells to disease pathogenesis. There is even less evidence about the role of NK cells in the more severe phenotype with juvenile-onset (J)SLE. In this study, analysis of the phenotype and function of NK cells in a large cohort of JSLE patients demonstrated that total NK cells, as well as perforin and granzyme A expressing NK cell populations, were significantly diminished in JSLE patients compared to age- and sex-matched healthy controls. The reduction in NK cell frequency was associated with increased disease activity, and transcriptomic analysis of NK populations from active and low disease activity JSLE patients versus healthy controls confirmed that disease activity was the main driver of differential NK cell gene expression. Pathway analysis of differentially expressed genes revealed an upregulation of interferon-α responses and a downregulation of exocytosis in active disease compared to healthy controls. Further gene set enrichment analysis also demonstrated an overrepresentation of the apoptosis pathway in active disease. This points to increased propensity for apoptosis as a potential factor contributing to NK cell deficiency in JSLE.

Factors associated with immune responses to SARS-CoV-2 vaccination in individuals with autoimmune diseases

Patients with autoimmune diseases are at higher risk for severe infection due to their underlying disease and immunosuppressive treatments. In this real-world observational study of 463 patients with autoimmune diseases, we examined risk factors for poor B and T cell responses to SARS-CoV-2 vaccination. We show a high frequency of inadequate anti-spike IgG responses to vaccination and boosting in the autoimmune population but minimal suppression of T cell responses. Low IgG responses in B cell-depleted patients with multiple sclerosis (MS) were associated with higher CD8 T cell responses. By contrast, patients taking mycophenolate mofetil (MMF) exhibited concordant suppression of B and T cell responses. Treatments with highest risk for low anti-spike IgG response included B cell depletion within the last year, fingolimod, and combination treatment with MMF and belimumab. Our data show that the mRNA-1273 (Moderna) vaccine is the most effective vaccine in the autoimmune population. There was minimal induction of either disease flares or autoantibodies by vaccination and no significant effect of preexisting anti-type I IFN antibodies on either vaccine response or breakthrough infections. The low frequency of breakthrough infections and lack of SARS-CoV-2-related deaths suggest that T cell immunity contributes to protection in autoimmune disease.

Signaling by Type I Interferons in Immune Cells: Disease Consequences

This review addresses interferon (IFN) signaling in immune cells and the tumor microenvironment (TME) and examines how this affects cancer progression. The data reveal that IFNs exert dual roles in cancers, dependent on the TME, exhibiting both anti-tumor activity and promoting cancer progression. We discuss the abnormal IFN signaling induced by cancerous cells that alters immune responses to permit their survival and proliferation.

Systemic lupus erythematosus following COVID-19 vaccination. A systematic review of case reports and case series

OBJECTIVE

Vaccination against SARS-CoV-2 reduced morbidity and mortality rates due to COVID-19 worldwide. However, several adverse effects have been documented and of great interest such as Systemic Lupus Erythematosus (SLE). The aim of the present study was to perform a systematic review of case reports and case series describing the development of SLE following COVID-19 against vaccination.

METHODS

Case report and case series studies were included. Systematic reviews, narratives, letters to the editor, correspondence, etc. were excluded. A selective bibliographic search was performed in the PubMed, Scopus, and EMBASE databases. In addition, the Web of Science platform was consulted. The Joanna Brigs Institute (JBI) tool was used to assess the risk of bias and quality of the studies. The Statistical Package for the Social Sciences (SPSS) 23.0 was used for the formal analysis of the descriptive data.

RESULTS

12 studies met the eligibility criteria and reported a total of 16 patients. The mean age was 42.4 ± 18.69 years. A slight predominance of post-vaccination SLE was observed in females (females (n = 9) and males (n = 7). A higher association was found with Pfizer-BioNTech-162b2 vaccine (75%), followed by Sinopharm (12.5%), Moderna (6.25%). and AstraZeneca (6.25%) vaccines. Most cases were associated with the first dose (56.25%), followed by the second dose (37.5%) and only one case associated with the third dose. The number of days elapsed from vaccine administration to the appearance of the first clinical manifestations was between 1 and 30 days. Mainly there was involvement of the musculoskeletal and cutaneous system. All patients responded well to treatment with good evolution and there was no case of death.

CONCLUSION

Cases of SLE associated with COVID-19 vaccination against are infrequent. However, clinical monitoring is recommended for persons receiving the SARS-CoV-2 vaccine, mainly those receiving the first dose and the Pfizer-BioNTech-162b2 vaccine.

Single-Cell Profiling of Bone Marrow B Cells and Early B Cell Developmental Disorders Associated With Systemic Lupus Erythematosus

OBJECTIVE

The peripheral B cell compartment is heavily disturbed in systemic lupus erythematosus (SLE), but whether B cells develop aberrantly in the bone marrow (BM) is largely unknown.

METHODS

We performed single-cell RNA/B cell receptor (BCR) sequencing and immune profiling of BM B cells and classified patients with SLE into two groups: early B cell (Pro-B and Pre-B) normal (EBnor) and EB defective/low (EBlo) groups.

RESULTS

The SLE-EBlo group exhibited more severe disease activity and proinflammatory status, overaction of type I interferon signaling and metabolic pathways within the B cell compartment, and aberrant BCR repertoires compared with the SLE-EBnor group. Moreover, in one patient with SLE who was initially classified in the SLE-EBlo group, early B cell deficiency and associated abnormalities were largely rectified in a second BM sample at the remission phase.

CONCLUSION

In summary, this study suggests that early B cell loss in BM defines a unique pathological state in a subset of patients with SLE that may play an active role in the dysregulated autoimmune responses.

Aberrant H3K4me3 modification of immune response genes in CD4+ T cells of patients with systemic lupus erythematosus

BACKGROUND

Increasing evidence has highlighted the significant role of histone modifications in pathogenesis of systemic lupus erythematosus (SLE). However, few studies have comprehensively analyzed trimethylation of histone H3 lysine 4 (H3K4me3) features at specific immune gene loci in SLE patients.

METHODS

We conducted H3K4me3 chromatin immunoprecipitation sequencing (ChIP-seq) on CD4+ T cells from SLE patients and healthy controls (HC). Differential H3K4me3 peaks were identified, followed by enrichment analysis. We integrated online RNA-seq and DNA methylation datasets to explore the relationship between H3K4me3 modification, DNA methylation and gene expression. We validated several upregulated peak regions by ChIP-qPCR and confirmed their impact on gene expression using RT-qPCR. Finally, we investigated the impact of H3K4 methyltransferases KMT2A on the expression of immune response genes.

RESULTS

we identified 147 downregulated and 2701 upregulated H3K4me3 peaks in CD4+ T cells of SLE. The upregulated peaks primarily classified as gained peaks and enriched in immune response genes such as FCGR2A, C5AR1, SERPING1 and OASL. Genes with upregulated H3K4me3 and downregulated DNA methylations in the promoter were highly expressed in SLE patients. These genes, including OAS1, IFI27 and IFI44L, were enriched in immune response pathways. The IFI44L locus also showed increased H3K27ac modification, chromatin accessibility and chromatin interactions in SLE. Moreover, knockdown of KMT2A can downregulate the expression of immune response genes in T cells.

CONCLUSION

Our study uncovers dysregulated H3K4me3 modification patterns in immune response genes loci, which also exhibit downregulated DNA methylation and higher mRNA expression in CD4+ T cells of SLE patients.

Metabolic imbalance driving immune cell phenotype switching in autoimmune disorders: Tipping the balance of T- and B-cell interactions

The interplay between the immune system and the metabolic state of a cell is intricate. In all phases of an immune response, the corresponding metabolic changes shall occur to support its modulation, in addition to the signalling through the cytokine environment and immune receptor stimulation. While autoimmune disorders may develop because of a metabolic imbalance that modulates switching between T-cell phenotypes, the effects that the interaction between T and B cells have on one another's cellular metabolism are yet to be understood in disease context. Here, we propose a perspective which highlights the potential of targeting metabolism to modulate T- and B-cell subtypes populations as well as T-B and B-T cell interactions to successfully treat autoimmune disorders. Specifically, we envision how metabolic changes can tip the balance of immune cells interactions, through definite mechanisms in both health and disease, to explain phenotype switches of B and T cells. Within this scenario, we highlight targeting metabolism that link inflammation, immunometabolism, epigenetics and ageing, is critical to understand inflammatory disorders. The combination of treatments targeting immune cells that cause (T/B) cell phenotype imbalances, and the metabolic pathways involved, may increase the effectiveness of treatment of autoimmune disorders, and/or ameliorate their symptoms to improve patients' quality of life.

The Link Between Dysregulated Immunometabolism and Vascular Damage: Implications for the Development of Atherosclerosis in Systemic Lupus Erythematosus and Other Rheumatic Diseases

A bimodal pattern of mortality in systemic lupus erythematosus (SLE) exists. Early-stage deaths are predominantly caused by infection, whereas later-stage deaths are mainly caused by atherosclerotic disease. Further, although SLE-related mortality has reduced considerably in recent years, cardiovascular (CV) events remain one of the leading causes of death in people with SLE. Accelerated atherosclerosis in SLE is attributed to both an increase in traditional CV risk factors and the inflammatory effects of SLE itself. Many of these changes occur within the microenvironment of the vascular-immune interface, the site of atherosclerotic plaque development. Here, an intimate interaction between endothelial cells, vascular smooth muscle cells, and immune cells dictates physiological vs pathological responses to a chronic type 1 interferon environment. Low-density neutrophils (LDNs) have also been implicated in eliciting vasculature-damaging effects at such lesion sites. These changes are thought to be governed by dysfunctional metabolism of immune cells in this niche due at least in part to the chronic induction of type 1 interferons. Understanding these novel pathophysiological mechanisms and metabolic pathways may unveil potential innovative pharmacological targets and therapeutic opportunities for atherosclerosis, as well as shed light on the development of premature atherosclerosis in patients with SLE who develop CV events.

SLE serum induces altered goblet cell differentiation and leakiness in human intestinal organoids

Human intestinal epithelial cells are the interface between luminal content and basally residing immune cells. They form a tight monolayer that constantly secretes mucus creating a multilayered protective barrier. Alterations in this barrier can lead to increased permeability which is common in systemic lupus erythematosus (SLE) patients. However, it remains unexplored how the barrier is affected. Here, we present an in vitro model specifically designed to examine the effects of SLE on epithelial cells. We utilize human colon organoids that are stimulated with serum from SLE patients. Combining transcriptomic with functional analyses revealed that SLE serum induced an expression profile marked by a reduction of goblet cell markers and changed mucus composition. In addition, organoids exhibited imbalanced cellular composition along with enhanced permeability, altered mitochondrial function, and an interferon gene signature. Similarly, transcriptomic analysis of SLE colon biopsies revealed a downregulation of secretory markers. Our work uncovers a crucial connection between SLE and intestinal homeostasis that might be promoted in vivo through the blood, offering insights into the causal connection of barrier dysfunction and autoimmune diseases.

Type I IFN in Glomerular Disease: Scarring beyond the STING

The field of nephrology has recently directed a considerable amount of attention towards the stimulator of interferon genes (STING) molecule since it appears to be a potent driver of chronic kidney disease (CKD). STING and its activator, the cyclic GMP-AMP synthase (cGAS), along with intracellular RIG-like receptors (RLRs) and toll-like receptors (TLRs), are potent inducers of type I interferon (IFN-I) expression. These cytokines have been long recognized as part of the mechanism used by the innate immune system to battle viral infections; however, their involvement in sterile inflammation remains unclear. Mounting evidence pointing to the involvement of the IFN-I pathway in sterile kidney inflammation provides potential insights into the complex interplay between the innate immune system and damage to the most sensitive segment of the nephron, the glomerulus. The STING pathway is often cited as one cause of renal disease not attributed to viral infections. Instead, this pathway can recognize and signal in response to host-derived nucleic acids, which are also recognized by RLRs and TLRs. It is still unclear, however, whether the development of renal diseases depends on subsequent IFN-I induction or other processes involved. This review aims to explore the main endogenous inducers of IFN-I in glomerular cells, to discuss what effects autocrine and paracrine signaling have on IFN-I induction, and to identify the pathways that are implicated in the development of glomerular damage.

Immunohistochemical expression of perforin in adult systemic lupus erythematosus associated macrophage activation syndrome: Clinicohematological correlation and literature review

OBJECTIVE

To study the bone marrow (BM) immunohistomorphological characteristics in adult systemic lupus erythematosus (SLE) associated macrophage activation syndrome (SLE-MAS).

MATERIALS AND METHODS

Immunohistochemical (IHC) expression of CD3, CD8, perforin (PFN), and CD163 was studied on BM trephine biopsies from 30 cytopenic adult SLE cases (male: female = 1:5, age; 24 years, range; 19-32) and compared them with ten age matched controls. Clinicopathological parameters were compared among the cases likely (L) or unlikely (U) to have MAS using probability scoring criteria. The best cut off laboratory parameters to discriminate between the two were obtained through receiver operator curve (ROC) analysis.

RESULTS

MAS occurred in 12/30 (40%) cases and was more commonly associated with prior immunosuppressive therapy (p = .07), ≥ 3 system involvement (p = .09), lower fibrinogen (p < .01), increased triglyceride (p = .002), increased BM hemophagocytosis (p = .002), and higher MAS score [185 (176-203) vs. 105 (77-119), p < .01] than MAS-U subgroup. Although PFN+CD8+ T lymphocytes significantly decreased among cases than controls (p < .05), it was comparable between MAS-L and MAS-U subgroups. Fibrinogen (< 2.4 g/L, AUC; 0.93, p < .01), hemophagocytosis score (> 1.5, AUC; 0.71, p = .03), and an MAS probability score of ≥ 164 (AUC; 1, p < .01) discriminated MAS from those without MAS.

CONCLUSION

We noted a decrease in perforin mediated CD8 + T cell cytotoxicity in SLE. Immunohistochemical demonstration of the same along with histiocytic hemophagocytosis on BM biopsy may be useful adjunct in early diagnosis and management of MAS in SLE.

[Interferon-α mediating the functional damage of CD56dimCD57+natural killer cells in peripheral blood of systemic lupus erythematosuss]

OBJECTIVE

To investigate the regulatory effect of interferon-α (IFN-α) on the apoptosis and killing function of CD56dimCD57+ natural killer (NK) cells in systemic lupus erythematosus (SLE) patients, and to explore the specific mechanism.

METHODS

A total of sixty-four newly treated SLE patients and sixteen healthy controls (HC) enrolled in the Second Hospital of Dalian Medical University were selected as the research subjects. And the gene expression levels of molecules related to NK cell-killing function were detected by real-time quantitative polymerase chain reaction. CD56dimCD57+ NK cells were co-cultured with the K562 cells, and the apoptotic K562 cells were labeled with Annexin-Ⅴ and 7-amino-actinomycin D. Peripheral blood mononuclear cells were treated with 20, 40, and 80 μmol/L hydrogen peroxide (H2O2), and treated without H2O2 as control, the expression level of perforin (PRF) was detected by flow cytometry. The concentration of IFN-α in serum was determined by enzyme linked immunosorbent assay. The expression levels of IFN-α receptors (IFNAR) on the surface of CD56dimCD57+ NK cells were detected by flow cytometry, and were represented by mean fluorescence intensity (MFI). CD56dimCD57+ NK cells were treated with 1 000 U/mL IFN-α for 24, 48 and 72 h, and no IFN-α treatment was used as the control, the apoptosis and the expression levels of mitochondrial reactive oxygen species (mtROS) were measured by flow cytometry and represented by MFI.

RESULTS

Compared with HC(n=3), the expression levels of PRF1 gene in peripheral blood NK cells of the SLE patients (n=3) were decreased (1.24±0.41 vs. 0.57±0.12, P=0.05). Compared with HC(n=5), the ability of peripheral blood CD56dimCD57+ NK cells in the SLE patients (n=5) to kill K562 cells was significantly decreased (58.61%±10.60% vs. 36.74%±6.27%, P < 0.01). Compared with the control (n=5, 97.51%±1.67%), different concentrations of H2O2 treatment significantly down-regulated the PRF expression levels of CD56dimCD57+ NK cells in a dose-dependent manner, the 20 μmol/L H2O2 PRF was 83.23%±8.48% (n=5, P < 0.05), the 40 μmol/L H2O2 PRF was 79.53%±8.56% (n=5, P < 0.01), the 80 μmol/L H2O2 PRF was 76.67%±7.16% (n=5, P < 0.01). Compared to HC (n=16), the serum IFN-α levels were significantly increased in the SLE patients (n=45) with moderate to high systemic lupus erythematosus disease activity index (SLEDAI≥10) [(55.07±50.36) ng/L vs. (328.2±276.3) ng/L, P < 0.001]. Meanwhile, compared with HC (n=6), IFNAR1 expression in peripheral blood CD56dimCD57+ NK cells of the SLE patients (n=6) were increased (MFI: 292.7±91.9 vs. 483.2±160.3, P < 0.05), and compared with HC (n=6), IFNAR2 expression in peripheral blood CD56dimCD57+ NK cells of the SLE patients (n=7) were increased (MFI: 643.5±113.7 vs. 919.0±246.9, P < 0.05). Compared with control (n=6), the stimulation of IFN-α (n=6) significantly promoted the apoptosis of CD56dimCD57+ NK cells (20.48%±7.01% vs. 37.82%±5.84%, P < 0.05). In addition, compared with the control (n=4, MFI: 1 049±174.5), stimulation of CD56dimCD57+ NK cells with IFN-α at different times significantly promoted the production of mtROS in a time-dependent manner, 48 h MFI was 3 437±1 472 (n=4, P < 0.05), 72 h MFI was 6 495±1 089 (n=4, P < 0.000 1), but there was no significant difference at 24 h of stimulation.

CONCLUSION

High serum IFN-α level in SLE patients may induce apoptosis by promoting mtROS production and inhibit perforin expression, which can down-regulate CD56dimCD57+ NK killing function.

COX5A as a potential biomarker for disease activity and organ damage in lupus

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease with limited therapeutic targets or clinical outcome predictors. This study aimed to gain more insights into the underlying immunological pathways and prognostic biomarkers of SLE. Integrated analyses of RNA-seq data from 64 SLE and 62 healthy controls, examining 27 immune cell types to explore the key pathways and driver genes in SLE pathogenesis. Single-cell RNA sequencing data from the skin and kidney were used to determine the association of COX5A expression with organ damage. The associations of COX5A with SLE phenotypes were further evaluated in two independent cohorts, and receiver operating characteristic (ROC) curves were constructed to assess the value of COX5A as a biomarker for disease activity and organ damage in SLE. We found that oxidative phosphorylation (OXPHOS) is the most significantly altered metabolic pathway in SLE, especially in effector T cells. Notably, we identified an OXPHOS-related enzyme, COX5A, whose expression was significantly higher in effector T cells than in naïve T cells and showed associations with disease activity, organ damage, and steroid treatment of SLE. Furthermore, ROC curves showed that COX5A is a robust biomarker for disease activity, kidney involvement, and new-onset skin lesions, with the area under the curve (AUC) values of 0.880, 0.801, and 0.805, respectively. Our results identified the OXPHOS signature as a prominent feature in SLE T cells, and COX5A as a potential candidate biomarker for disease activity and organ damage in SLE.

Mitochondrial Lon protease promotes CD4+ T cell activation by activating the cGAS-STING-TBK1 axis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which autoreactive CD4+ T cells play an essential role. We extracted CD4+ T cells from SLE-prone Fcgr2b-/- mice to elaborate the mechanism of mitochondrial Lon protease in CD4+ T cell activation in SLE. Transcriptome sequencing was performed in SLE-prone Fcgr2b-/- mice, and the stimulator of interferon gene (STING) related to SLE was obtained. It was demonstrated that STING expression was elevated in CD4+ T cells in SLE-prone Fcgr2b-/- mice. The downstream genes and pathways of STING were predicted by GO and KEGG approaches. The data indicated that STING regulated IFN signaling to promote CD4+ T cell activation in SLE-prone Fcgr2b-/- mice. Next, the interaction of cGAS, STING, TBK1, and IFN-I was verified by Co-IP assay. Moreover, the roles of cGAS, STING, and TBK1 in activating CD4+ T cells from SLE-prone Fcgr2b-/- mice were evaluated using gain- or loss-of-function experiments. Mechanistically, cGAS upregulated the IFN-I signaling pathway by directly interacting with STING and TBK1, contributing to CD4+ T cell activation. Besides, cytosolic mtDNA could activate CD4+ T cell activation in SLE-prone Fcgr2b-/- mice by upregulating the cGAS-STING-TBK1 axis. The function of mitochondrial Lon protease in oxidative damage and mtDNA release in CD4+ T cells of SLE-prone Fcgr2b-/- mice were explored. Mitochondrial Lon protease enhanced mtDNA release into the cytoplasm under oxidative stress. Collectively, our work indicates that mitochondrial Lon protease enhances CD4+ T cell activation by inducing mtDNA leakage and offers new candidate targets for developing diagnostic and therapeutic strategies.

Association of regulatory T cells with renal outcomes in patients with proliferative lupus nephritis

BACKGROUND

Despite progress in the diagnosis and treatment of proliferative lupus nephritis (PLN), the prognosis remains unfavorable. Previous investigations have suggested that the deficiency of regulatory T cells (Tregs) is involved in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis (LN). But the prognostic value of Tregs in PLN remains controversial. This study aimed to investigate the association of Tregs with renal outcomes in patients with PLN.

METHODS

The baseline and follow-up data of patients with biopsy-proven PLN were collected in this study. All patients were divided into two groups according to whether the renal endpoint event occurred. Clinicopathologic features and therapeutic responses were compared between the two groups. Cox regression analyses curve fitting and threshold effect analysis were implemented to investigate the relationship between Tregs level and the long-term renal outcomes. The renal endpoint was defined as end-stage kidney disease (ESKD) or doubling the SCr value.

RESULTS

A total of 405 PLN patients were included. After a follow-up of 71.53 (53.13-97.47) months, 42 (10.4%) patients reached the renal endpoint. The Treg cell counts (16/μL) in the renal endpoint group were significantly decreased than that in the non-renal endpoint group (p < 0.001). Univariate and multivariate Cox regression analyses showed that the high level of Tregs was an independent protective factor for the long-term renal prognosis of PLN. Smooth curve fitting of the generalized additive mixed model analysis indicated that the risk of renal endpoint first decreased with Tregs and then slightly increased along with Treg cell levels. The segmented linear model revealed that when Treg cell counts <46/μL, the risk of renal endpoint decreased by 6.8% for every 1 μL increase in Treg levels (p = 0.0029).

CONCLUSION

Treg cell counts are closely related to the long-term renal outcomes of patients with PLN, and increasing Treg cell levels may play an important role in improving the prognosis of the kidney, but there may be a turning point (i.e., threshold effect) at the Treg cell counts that leads to directional changes in the renal outcomes.

Single-Cell RNA Sequencing Reveals Immuno-Oncology Characteristics of Tumor-Infiltrating T Lymphocytes in Photodynamic Therapy-Treated Colorectal Cancer Mouse Model

Photodynamic therapy (PDT) has shown promise in reducing metastatic colorectal cancer (CRC); however, the underlying mechanisms remain unclear. Modulating tumor-infiltrating immune cells by PDT may be achieved, which requires the characterization of immune cell populations in the tumor microenvironment by single-cell RNA sequencing (scRNA-seq). Here, we determined the effect of Chlorin e6 (Ce6)-mediated PDT on tumor-infiltrating T cells using scRNA-seq analysis. We used a humanized programmed death-1/programmed death ligand 1 (PD-1/PD-L1) MC38 cell allograft mouse model, considering its potential as an immunogenic cancer model and in combination with PD-1/PD-L1 immune checkpoint blockade. PDT treatment significantly reduced tumor growth in mice containing hPD-1/PD-L1 MC38 tumors. scRNA-seq analysis revealed that the PDT group had increased levels of CD8+ activated T cells and CD8+ cytotoxic T cells, but decreased levels of exhausted CD8+ T cells. PDT treatment also enhanced the infiltration of CD8+ T cells into tumors and increased the production of key effector molecules, including granzyme B and perforin 1. These findings provide insight into immune-therapeutic modulation for CRC patients and highlight the potential of PDT in overcoming immune evasion and enhancing antitumor immunity.

SOCS3 deletion in effector T cells confers an anti-tumorigenic role of IL-6 to the pro-tumorigenic cytokine

Interleukin (IL)-6 is abundantly expressed in the tumor microenvironment and is associated with poor patient outcomes. Here, we demonstrate that the deletion of the suppressor of cytokine signaling 3 (SOCS3) in T cells potentiates anti-tumor immune responses by conferring the anti-tumorigenic function of IL-6 in mouse and human models. In Socs3-deficient CD8+ T cells, IL-6 upregulates the expression of type I interferon (IFN)-regulated genes and enhances the anti-tumor effector function of T cells, while also modifying mitochondrial fitness to increase mitochondrial membrane potential and reactive oxygen species (ROS) levels and to promote metabolic glycolysis in the energy state. Furthermore, Socs3 deficiency reduces regulatory T cells and increases T helper 1 (Th1) cells. SOCS3 knockdown in human chimeric antigen receptor T (CAR-T) cells exhibits a strong anti-tumor response in humanized mice. Thus, genetic disruption of SOCS3 offers an avenue to improve the therapeutic efficacy of adoptive T cell therapy.

Molecular characterization of PANoptosis-related genes with features of immune dysregulation in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease. PANoptosis is a novel form of programmed cell death involved in various inflammatory diseases. This study aimed to identify the differentially-expressed PANoptosis-related genes (PRGs) involved in immune dysregulation in SLE. Five key PRGs, including ZBP1, MEFV, LCN2, IFI27, and HSP90AB1, were identified. The prediction model with these 5 key PRGs showed a good diagnostic performance in distinguishing SLE patients from controls. These key PRGs were associated with memory B cells, neutrophils and CD8 + T cells. Besides, these key PRGs were significantly enriched in pathways involving the type I interferon responses and IL-6-JAK-STAT3 signaling. The expression levels of the key PRGs were validated in peripheral blood mononuclear cells (PBMCs) of patients with SLE. Our findings suggest that PANoptosis may be implicated in the immune dysregulation in SLE by regulating the interferons and JAK-STAT signaling pathways in memory B cells, neutrophils and CD8 + T cells.

Pathogenesis of systemic lupus erythematosus: risks, mechanisms and therapeutic targets

Research elucidating the pathogenesis of systemic lupus erythematosus (SLE) has defined two critical families of mediators, type I interferon (IFN-I) and autoantibodies targeting nucleic acids and nucleic acid-binding proteins, as fundamental contributors to the disease. On the fertile background of significant genetic risk, a triggering stimulus, perhaps microbial, induces IFN-I, autoantibody production or most likely both. When innate and adaptive immune system cells are engaged and collaborate in the autoimmune response, clinical SLE can develop. This review describes recent data from genetic analyses of patients with SLE, along with current studies of innate and adaptive immune function that contribute to sustained IFN-I pathway activation, immune activation and autoantibody production, generation of inflammatory mediators and tissue damage. The goal of these studies is to understand disease mechanisms, identify therapeutic targets and stimulate development of therapeutics that can achieve improved outcomes for patients.

Canagliflozin impairs T cell effector function via metabolic suppression in autoimmunity

Augmented T cell function leading to host damage in autoimmunity is supported by metabolic dysregulation, making targeting immunometabolism an attractive therapeutic avenue. Canagliflozin, a type 2 diabetes drug, is a sodium glucose co-transporter 2 (SGLT2) inhibitor with known off-target effects on glutamate dehydrogenase and complex I. However, the effects of SGLT2 inhibitors on human T cell function have not been extensively explored. Here, we show that canagliflozin-treated T cells are compromised in their ability to activate, proliferate, and initiate effector functions. Canagliflozin inhibits T cell receptor signaling, impacting on ERK and mTORC1 activity, concomitantly associated with reduced c-Myc. Compromised c-Myc levels were encapsulated by a failure to engage translational machinery resulting in impaired metabolic protein and solute carrier production among others. Importantly, canagliflozin-treated T cells derived from patients with autoimmune disorders impaired their effector function. Taken together, our work highlights a potential therapeutic avenue for repurposing canagliflozin as an intervention for T cell-mediated autoimmunity.

Mitochondria-related genes and metabolic profiles of innate and adaptive immune cells in primary Sjögren's syndrome

Background

Primary Sjogren's syndrome (pSS) is a prototypical systemic autoimmune disease characterised by lymphocyte infiltration and immune-complex deposition in multiple organs. The specific distribution of immune cell populations and their relationship with mitochondria remain unknown.

Methods

Histological analysis was performed to assess the specific distribution of innate and adaptive immune cell populations in labial salivary gland (LSG) samples from 30 patients with pSS and 13 patients with non-pSS. The ultrastructural morphometric features of mitochondria within immune cells were observed under the transmission electron microscope (TEM). RNA sequencing was performed on LSG samples from 40 patients with pSS and 7 non-pSS patients. The Single-sample Gene Set Enrichment Analysis (ssGSEA), ESTIMATE, and CIBERSORT algorithms and Pearson correlation coefficients were used to examine the relationship between mitochondria-related genes and immune infiltration. Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify the mitochondria-specific genes and the related pathways based on the immune cell types.

Results

HE staining revealed a massive infiltration of plasma cells with abundant immunoglobulin protein distributed around phenotypically normal-appearing acinar and ductal tissues of patients with pSS. Immunohistochemical analyses revealed that innate immune cells (macrophages, eosinophils and NK cells) were distributed throughout the glandular tissue. Dominant adaptive immune cell infiltration composed of B cells, CD4⁺T cells and CD8⁺ T cells or ectopic lymphoid follicle-like structures were observed in the LSGs of patients with pSS. TEM validated the swelling of mitochondria with disorganised cristae in some lymphocytes that had invaded the glandular tissue. Subsequently, bioinformatic analysis revealed that innate and adaptive immune cells were associated with different mitochondrial metabolism pathways. Mitochondrial electron transport and respiratory chain complexes in the glandular microenvironment were positively correlated with innate immune cells, whereas amino acid and nucleic acid metabolism were negatively correlated with adaptive immune cells. In addition, mitochondrial biogenesis and mitochondrial apoptosis in the glandular microenvironment were closely associated with adaptive immune cells.

Conclusion

Innate and adaptive immune cells have distinct distribution profiles in the salivary gland tissues of patients with pSS and are associated with different mitochondrial metabolic pathways, which may contribute to disease progression.

NAD+ Precursors and Intestinal Inflammation: Therapeutic Insights Involving Gut Microbiota

The oxidized form of nicotinamide adenine dinucleotide (NAD+) is a critical metabolite for living cells. NAD+ may act either as a cofactor for many cellular reactions as well as a coenzyme for different NAD+-consuming enzymes involved in the physiological homeostasis of different organs and systems. In mammals, NAD+ is synthesized from either tryptophan or other vitamin B3 intermediates that act as NAD+ precursors. Recent research suggests that NAD+ precursors play a crucial role in maintaining the integrity of the gut barrier. Indeed, its deficiency has been associated with enhanced gut inflammation and leakage, and dysbiosis. Conversely, NAD+-increasing therapies may confer protection against intestinal inflammation in experimental conditions and human patients, with accumulating evidence indicating that such favorable effects could be, at least in part, mediated by concomitant changes in the composition of intestinal microbiota. However, the mechanisms by which NAD+-based treatments affect the microbiota are still poorly understood. In this context, we have focused specifically on the impact of NAD+ deficiency on intestinal inflammation and dysbiosis in animal and human models. We have further explored the relationship between NAD+ and improved host intestinal metabolism and immunity and the composition of microbiota in vivo. Overall, this comprehensive review aims to provide a new perspective on the effect of NAD+-increasing strategies on host intestinal physiology.

Advanced methods and novel biomarkers in autoimmune diseases ‑ a review of the recent years progress in systemic lupus erythematosus

There are several autoimmune and rheumatic diseases affecting different organs of the human body. Multiple sclerosis (MS) mainly affects brain, rheumatoid arthritis (RA) mainly affects joints, Type 1 diabetes (T1D) mainly affects pancreas, Sjogren's syndrome (SS) mainly affects salivary glands, while systemic lupus erythematosus (SLE) affects almost every organ of the body. Autoimmune diseases are characterized by production of autoantibodies, activation of immune cells, increased expression of pro-inflammatory cytokines, and activation of type I interferons. Despite improvements in treatments and diagnostic tools, the time it takes for the patients to be diagnosed is too long, and the main treatment for these diseases is still non-specific anti-inflammatory drugs. Thus, there is an urgent need for better biomarkers, as well as tailored, personalized treatment. This review focus on SLE and the organs affected in this disease. We have used the results from various rheumatic and autoimmune diseases and the organs involved with an aim to identify advanced methods and possible biomarkers to be utilized in the diagnosis of SLE, disease monitoring, and response to treatment.

Systemic lupus erythematosus: latest insight into etiopathogenesis

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder of unknown etiology. Multifactorial interaction among various susceptible factors such as environmental, hormonal, and genetic factors makes it more heterogeneous and complex. Genetic and epigenetic modifications have been realized to regulate the immunobiology of lupus through environmental modifications such as diet and nutrition. Although these interactions may vary from population to population, the understanding of these risk factors can enhance the perception of the mechanistic basis of lupus etiology. To recognize the recent advances in lupus, an electronic search was conducted among search engines such as Google Scholar and PubMed, where we found about 30.4% publications of total studies related to genetics and epigenetics, 33.5% publications related to immunobiology and 34% related to environmental factors. These outcomes suggested that management of diet and lifestyle have a direct relationship with the severity of lupus that influence via modulating the complex interaction among genetics and immunobiology. The present review emphasizes the knowledge about the multifactorial interactions between various susceptible factors based on recent advances that will further update the understanding of mechanisms involved in disease pathoetiology. Knowledge of these mechanisms will further assist in the creation of novel diagnostic and therapeutic options.

B cell activation via immunometabolism in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease involving multiple organs in which B cells perform important functions such as antibody and cytokine production and antigen presentation. B cells are activated and differentiated by the primary B cell receptor, co-stimulatory molecule signals-such as CD40/CD40L-, the Toll-like receptors 7,9, and various cytokine signals. The importance of immunometabolism in the activation, differentiation, and exerting functions of B cells and other immune cells has been widely reported in recent years. However, the regulatory mechanism of immunometabolism in B cells and its involvement in SLE pathogenesis remain elusive. Similarly, the importance of the PI3K-Akt-mTOR signaling pathway, glycolytic system, and oxidative phosphorylation has been demonstrated in the mechanisms of B cell immunometabolic activation, mainly in mouse studies. However, the activation of the mTOR pathway in B cells in patients with SLE, the induction of plasmablast differentiation through metabolic and transcription factor regulation by mTOR, and the involvement of this phenomenon in SLE pathogenesis are unclear. In our studies using activated B cells derived from healthy donors and from patients with SLE, we observed that methionine, an essential amino acid, is important for mTORC1 activation. Further, we observed that splenic tyrosine kinase and mTORC1 activation synergistically induce EZH2 expression and plasmablasts by suppressing BACH2 expression through epigenomic modification. Additionally, we identified another mechanism by which the glutaminolysis-induced enhancement of mitochondrial function promotes plasmablast differentiation in SLE. In this review, we focused on the SLE exacerbation mechanisms related to the activation of immune cells-especially B cells-and immunometabolism and reported the latest findings in the field.

A cellular overview of immunometabolism in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease, characterized by a breakdown of immune tolerance and the development of autoantibodies against nucleic self-antigens. Immunometabolism is a rapidly expanding scientific field investigating the metabolic programming of cells of the immune system. During the normal immune response, extensive reprogramming of cellular metabolism occurs, both to generate adenosine triphosphate and facilitate protein synthesis, and also to manage cellular stress. Major pathways upregulated include glycolysis, oxidative phosphorylation, the tricarboxylic acid cycle and the pentose phosphate pathway, among others. Metabolic reprogramming also occurs to aid resolution of inflammation. Immune cells of both patients with SLE and lupus-prone mice are characterized by metabolic abnormalities resulting in an altered functional and inflammatory state. Recent studies have described how metabolic reprogramming occurs in many cell populations in SLE, particularly CD4+ T cells, e.g. favouring a glycolytic profile by overactivation of the mechanistic target of rapamycin pathway. These advances have led to an increased understanding of the metabolic changes affecting the inflammatory profile of T and B cells, monocytes, dendritic cells and neutrophils, and how they contribute to autoimmunity and SLE pathogenesis. In the current review, we aim to summarize recent advances in the field of immunometabolism involved in SLE and how these could potentially lead to new therapeutic strategies in the future.

NAD+ metabolism-based immunoregulation and therapeutic potential

Nicotinamide adenine dinucleotide (NAD⁺) is a critical metabolite that acts as a cofactor in energy metabolism, and serves as a cosubstrate for non-redox NAD⁺-dependent enzymes, including sirtuins, CD38 and poly(ADP-ribose) polymerases. NAD⁺ metabolism can regulate functionality attributes of innate and adaptive immune cells and contribute to inflammatory responses. Thus, the manipulation of NAD⁺ bioavailability can reshape the courses of immunological diseases. Here, we review the basics of NAD⁺ biochemistry and its roles in the immune response, and discuss current challenges and the future translational potential of NAD⁺ research in the development of therapeutics for inflammatory diseases, such as COVID-19.

Exercise and COVID-19: exercise intensity reassures immunological benefits of post-COVID-19 condition

Any form of physical activity, including exercise, has various benefits at the physiological (improving cardiac and respiratory functions, increasing skeletal muscle mass, and maintaining homeostasis) and psychological levels (improving cognitive function, reducing anxiety and depression) which help to combat any type of infection. In contrast, the infectivity ratio could reduce the physical activity of an individual, such as performing a habitual exercise. Adaptation to different exercise strategies including intensity and duration may better increase physical performance and improve the symptoms. For example, low to moderate intensity perhaps fails to induce this adaptive process, while high-intensity of exercise compromises immune health. This can aggravate the infection rate (Open window theory). However, high intensity with a shorter time produces various morphological alterations in the primary organs including the lungs and heart, which facilitate life support in COVID-19 patients. However, less information about exercise protocols failed to assure the benefits of exercise to COVID-19 patients, particularly post-COVID-19 conditions. Therefore, this review will answer how exercise intensity is crucial to reassure the exercise benefits for promoting safe participation before infection and post-COVID-19 conditions.