New insights into the immunopathogenesis of systemic lupus erythematosus

Predicting and validating the risk of interstitial lung disease in systemic lupus erythematosus

OBJECTIVE

Our study aimed toconstruct a web-based calculator to predict high risk patients of interstitial lung disease (ILD) in systemic lupus erythematosus (SLE).

METHODS

This retrospective study comprised training and test cohorts, including 581 and 86 patients, respectively. Univariate, least absolute shrinkage and selection operator (LASSO), random forest (RF), eXtreme Gradient Boosting (XGBoost), and logistic regression (LR) analyses were performed. A Venn diagram was used to investigate critical features. Receiver operating characteristic (ROC) analysis and decision curve analysis were used to evaluate the model's performance. Risk stratification was performed using the best ROC cut-off value. The web-based calculator was established using Streamlit software.

RESULTS

Characteristics such as Raynaud's phenomenon, pulmonary artery systolic pressure, serositis, anti-U1RNP antibodies, anti-Ro52 antibodies, C-reactive protein, age, and disease course were associated with SLE complicated by ILD (SLE-ILD). LR-Venn, RF-Venn, XGBoost-Venn, LASSO-logic, RF, and XGBoost models were constructed. In training cohort, the XGBoost model demonstrated the highest area under the ROC curve (AUC, 0.890; cut-off value, 0.197; sensitivity, 0.793; specificity, 0.836) and provideda netbenefitin decision curve analysis (odds ratio [OR] for SLE-ILD [high- vs. low-risk], 19.6). The model was validated in the test cohort (AUC, 0.866; sensitivity, 0.722; specificity, 0.897; OR, 22.7). Furthermore, an XGBoost model-based web calculator was developed.

CONCLUSION

Our web calculator (https://st-xgboost-app-kcv9qm.streamlit.app/) greatly improved risk prediction for SLE-ILD and was implemented effectively.

Nanoparticles encapsulating antigenic peptides induce tolerogenic dendritic cells in situ for treating systemic lupus erythematosus

Using Tetrahedral framework nucleic acids, we combined antigenic peptides to create the "DART" vaccine: DNA framework-Antigenic peptide-RNA modification-Targeting aptamer coupling. Generating antigen-specific tolerogenic dendritic cells (tolDCs), for systemic lupus erythematosus (SLE) is a potential therapeutic strategy for addressing compromised autoimmune tolerance. However, simple antigenic peptides degrade easily, lack specificity for delivery to dendritic cells (DCs), and cannot transform DCs to tolDCs. Therefore, this study aims to employ DART to generate tolDCs and compare DART-treated DCs to tolDCs. DART improved peptide stability, specifically targeted DCs, induced tolDCs in situ, and showed promising outcomes in mitigating SLE symptoms in the MRL/lpr mouse model. DART effectively normalized the plasma cytokine levels, glomerulonephritis, and joint lesions in MRL/lpr mice. These findings highlight the potential of the DART vaccine to induce transformation of DCs to tolDCs and address SLE symptoms, suggesting novel therapeutic utility. These findings may advance vaccine design for various autoimmune diseases.

Caffeine improves systemic lupus erythematosus endothelial dysfunction by promoting endothelial progenitor cells survival

OBJECTIVE

We studied the role of caffeine intake on endothelial function in SLE by assessing its effect on circulating endothelial progenitor cells (EPCs) both ex vivo in SLE patients and in vitro in healthy donors (HD) treated with SLE sera.

METHODS

We enrolled SLE patients without traditional cardiovascular risks factors. Caffeine intake was evaluated with a 7-day food frequency questionnaire. EPCs percentage was assessed by flow cytometry analysis and, subsequently, EPCs pooled from six HD were co-cultured with caffeine with and without SLE sera. After 7 days, we evaluated cells' morphology and ability to form colonies, the percentage of apoptotic cells by flow cytometry analysis and the levels of autophagy and apoptotic markers by western blot. Finally, we performed a western blot analysis to assess the A2AR/SIRT3/AMPK pathway.

RESULTS

We enrolled 31 SLE patients, and observed a positive correlation between caffeine intake and circulating EPCs percentage. HD EPCs treated with SLE sera and caffeine showed an improvement in morphology and in number of EPCs colony-forming units in comparison with those incubated without caffeine. Caffeine was able to restore autophagy and apoptotic markers in HD EPCs as before SLE sera treatment. Finally, caffeine treatment was able to significantly reduce A2AR levels, leading to an increase in protein levels of SIRT3 and subsequently AMPK phosphorylation.

CONCLUSIONS

Caffeine intake positively correlated with the percentage of circulating EPCs in SLE patients; moreover, caffeine in vitro treatment was able to improve EPC survival and vitality through the inhibition of apoptosis and the promotion of autophagy via A2AR/SIRT3/AMPK pathway.

Decoding tryptophan: Pioneering new frontiers in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that affects multiple organ systems, with its pathogenesis intricately tied to genetic, environmental, and immune regulatory factors. In recent years, the aberration of tryptophan metabolism has emerged as a key player in the disease, particularly through the activation of the kynurenine pathway and its influence on immune regulation. This review delves into the critical pathways of tryptophan metabolism and its profound impact on the multi-system manifestations of SLE, including its connections to the nervous system, kidneys, skin, and other organs. Additionally, it examines how tryptophan metabolism modulates the function of various immune cell types. The review also explores potential therapeutic avenues targeting tryptophan metabolism, such as dietary interventions, probiotic modulation, IDO expression inhibition, and immunoadsorption techniques. While current research has underscored the pivotal role of tryptophan metabolism in the onset and progression of SLE, its full therapeutic potential remains to be fully elucidated. This review aims to provide a solid scientific foundation for therapeutic strategies based on modulating tryptophan metabolism in SLE, offering a comprehensive overview of both clinical and basic research in this rapidly evolving field.

Integrated bioinformatics and validation reveal TMEM45A in systemic lupus erythematosus regulating atrial fibrosis in atrial fibrillation

BACKGROUND

Accumulative evidence has shown that systemic lupus erythematosus (SLE) increases the risk of various cardiovascular diseases including atrial fibrillation (AF). The study aimed to screen potential key genes underlying co-pathogenesis between SLE and AF, and to discover therapeutic targets for AF.

METHODS

Differentially expressed genes (DEGs) were identified, and co-expressed gene modules were obtained through weighted gene co-expression network analysis (WGCNA) based on the AF and SLE expression profiles from the GEO database. Subsequently, machine learning algorithms including LASSO regression and support vector machine (SVM) method were employed to identify the candidate therapeutic target for SLE-related AF. Furthermore, the therapeutic role of TMEM45A was validated both in vivo and vitro.

RESULTS

Totally, 26 DEGs were identified in SLE and AF. The PPI network combined with WGCNA identified 51 key genes in SLE and AF. Ultimately, Machine learning-based methods screened three hub genes in SLE combined with AF, including TMEM45A, ITGB2 and NFKBIA. The cMAP analysis exposed KI-8751 and YM-155 as potential drugs for AF treatment. Regarding TMEM45A, the aberrant expression was validated in blood of SLE patients. Additionally, TMEM45A expression was up-regulated in the atrial tissue of patients with AF. Furthermore, TMEM45A knockdown alleviated AF occurrence and atrial fibrosis in vivo and Ang II-induced NRCFs fibrosis in vitro.

CONCLUSION

The crosstalk genes underlying co-pathogenesis between SLE and AF were unraveled. Furthermore, the pro-fibrotic role of TMEM45A was validated in vivo and vitro, highlighting its potential as a therapeutic target for AF.

Evaluation of thrombospondin 1 as a novel biomarker in pediatric-onset systemic lupus erythematosus

OBJECTIVE

This study aimed to assess the potential of thrombospondin 1 (TBS-1) as a biomarker for pediatric-onset systemic lupus erythematosus (pSLE) and investigated its association with clinical characteristics and other laboratory tests in pSLE.

METHODS

A total of 112 pSLE and 50 age-matched and gender-matched healthy controls (HCs) were recruited in this study from January 2022 to June 2023 at West China Second University Hospital, Sichuan university. Plasma TBS-1 levels were measured, and clinical and laboratory findings were collected from the medical database.

RESULTS

The plasma TBS-1 level was significantly lower in pSLE patients (26778 ng/mL, IQR: 9875-59011) compared to HCs (100583 ng/mL, IQR: 58327-189547) (P < 0.0001). ROC analysis demonstrated that TBS-1 could effectively differentiate pSLE patients and HCs (AUC: 0.845, 95%CI: 0.785-0.905, P < 0.0001) with an optimal cut-off was 49,937 ng/mL, yielding a sensitivity of 84% and specificity of 70.5% based on the Youden index. Compared to TBS-1 positive patients, TBS-1 negative patients exhibited significant reductions in hemoglobin, IgM, and fibrinogen levels.

CONCLUSION

In light of the current data, the efficacy of TBS-1 as a biomarker in pSLE diverged from its performance in adult SLE. In summary, TBS-1 shows potential as a biomarker for pSLE, particularly in hematological manifestations. Further investigations are essential to delve into the immunomodulatory roles of TBS-1 in the autoimmune pathways of pSLE.

Precision Medicine in Rheumatology: The Role of Biomarkers in Diagnosis and Treatment Optimization

Rheumatic diseases encompass a wide range of autoimmune and inflammatory disorders, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriatic arthritis (PsA), and systemic sclerosis (SSc). These conditions often result in chronic pain, disability, and reduced quality of life, with unpredictable disease courses that may lead to joint destruction, organ damage, or systemic complications. Biomarkers, defined as measurable indicators of biological processes or conditions, have the potential to transform clinical practice by improving disease diagnosis, monitoring, prognosis, and treatment decisions. While significant strides have been made in identifying and validating biomarkers in rheumatic diseases, challenges remain in their standardization, clinical utility, and integration into routine practice. This review provides an overview of the current state of biomarkers in rheumatic diseases, their roles in clinical settings, and the emerging advancements in the field.

The aryl hydrocarbon receptor affects the inflammatory response of bone marrow mesenchymal stem cell via the hippo-YAP pathway to exacerbate systemic lupus erythematosus

The impaired immune regulation of bone marrow mesenchymal stem cells (BM-MSCs) disrupts T-cell homeostasis and alters the immunological environment in individuals with systemic lupus erythematosus (SLE). However, the specific molecular mechanisms underlying the defective immune functions of BM-MSCs in patients with SLE remain unclear. Here, we report that BM-MSCs derived from MRL/lpr mice exhibit a diminished proliferative capacity, elevated levels of aryl hydrocarbon receptor (AhR) and increased levels of secreted proinflammatory cytokines, including IL-1β, IL-6, and TNF-α. These BM-MSCs can increase splenocyte proliferation and upregulate the expression of retinoic acid receptor-related orphan receptor gamma t (RORγt) in EL4 cells, which constitute a murine T-cell lymphoblastic leukemia cell line. Furthermore, MRL/lpr mice treated with FICZ (an AhR agonist) displayed splenomegaly and exacerbated renal pathology, alongside increased levels of AhR, and inflammatory cytokines. Notably, BM-MSCs isolated from FICZ-treated mice also facilitated splenocyte proliferation and increased the RORγt level in EL4 cells during coculture. Similar effects were observed when BM-MSCs were exposed to FICZ in vitro, but these effects were reversed by the administration of CH223191 (an AhR antagonist). Additionally, the expression of Yes-associated protein (YAP) was significantly increased in both MRL/lpr mice and FICZ-treated BM-MSCs. Importantly, verteporfin (a Hippo-YAP inhibitor) attenuated the elevated RORγt levels in EL4 cells and the increased splenocyte proliferation. This study advances our understanding of SLE pathogenesis by pinpointing AhR as a pivotal modulator of the inflammatory response of BM-MSCs through the Hippo-YAP pathway in individuals with SLE. This novel insight not only enriches the current knowledge of SLE mechanisms but also highlights new potential therapeutic targets for SLE.

Helix-Guarded Molecular Clips for Cell-Free DNA Scavenging and Treatment of Systemic Lupus Erythematosus

Immune disorders induced by cell-free DNA (cfDNA) account for the incidence and deterioration of systemic lupus erythematosus (SLE). Scavenging of cfDNA using cationic polymers represents a promising modality for SLE management. However, they bind cfDNA mainly via electrostatic interaction, which would result in an undesired discharge of the captured cfDNA upon competitive replacement by the negatively charged serum/intracellular components. Inspired by the natural recognition mechanism of biomacromolecules via spatial matching, we herein developed a library of dendrimer-templated, spherical, α-helical, and guanidine-rich polypeptides as molecular clips for cfDNA scavenging. Upon optimization of the polypeptide length and density on the dendrimer surface, the top-performing G3-8 was identified, which could tightly confine cfDNA within the cavity between the adjacent, rod-like α-helices. As thus, the helical G3-8 but not the random-coiled analogue D,L-G3-8 enabled robust cfDNA scavenging under serum-rich conditions to inhibit TLR9 activation and inflammation. In SLE mice, i.v. injected G3-8 efficiently prevented organ failure and inhibited inflammation by scavenging cfDNA. This study provides an enlightened strategy to stably bind and scavenge cfDNA and may shift the current paradigm of SLE management.

Petroselinic Acid from Apiaceae Family Plants Ameliorates Autoimmune Disorders Through Suppressing Cytosolic-Nucleic-Acid-Mediated Type I Interferon Signaling

The recognition of cytosolic nucleic acids is a critical step in the host immune response against danger signals, such as molecular patterns from pathogens or tissue damage. Nonetheless, over-reactivity to self-nucleic acids leads to the sustained production of type I interferon (IFN), mediated either by cGAS or RLR, contributing to the pathogenesis of certain autoimmune diseases, such as Aicardi-Goutières syndrome (AGS). Therefore, inhibiting excessive IFN production represents a potential therapeutic strategy for such autoimmune conditions. In this study, we discovered that petroselinic acid (PA), a natural compound isolated from Apiaceae family plants, effectively suppresses type I IFN production induced by cytosolic nucleic acids. Mechanistic investigations revealed that PA inhibits the phosphorylation of TBK1 and IRF3, which are key nodal proteins within the type I interferon pathway. Notably, molecular docking suggests potential binding between PA and cytosolic nucleic acid sensors, such as cGAS and RIG-I. Moreover, we found that PA effectively attenuates the expression of type I IFN and their downstream interferon-stimulated genes (ISGs) in models of AGS autoimmune disease characterized by excessive nucleic acid accumulation. Thus, our research identifies a natural compound that offers a promising strategy for treating autoimmune diseases resulting from aberrant self-nucleic acid recognition and the hyperactivation of type I interferon.

Translocating gut pathobiont Enterococcus gallinarum induces TH17 and IgG3 anti-RNA-directed autoimmunity in mouse and human

Chronic autoimmune diseases often lead to long-term sequelae and require lifelong immunosuppression because of an incomplete understanding of the triggers and drivers in genetically predisposed patients. Gut bacteria that escape the gut barrier, known as translocating gut pathobionts, have been implicated as instigators and perpetuators of extraintestinal autoimmune diseases in mice. The gut microbial contributions to autoimmunity in humans remain largely unclear, including whether specific pathological human adaptive immune responses are triggered by such pathobionts. Here, we show that the translocating pathobiont Enterococcus gallinarum can induce both human and mouse interferon-γ+ T helper 17 (TH17) differentiation and immunoglobulin G3 (IgG3) subclass switch of anti-E. gallinarum RNA antibodies, which correlated with anti-human RNA autoantibody responses in patients with systemic lupus erythematosus (SLE) and autoimmune hepatitis, two extraintestinal autoimmune diseases. E. gallinarum RNA, but not human RNA, triggered Toll-like receptor 8 (TLR8), and TLR8-mediated human monocyte activation promoted human TH17 induction by E. gallinarum. Translocation of the pathobiont triggered increased anti-RNA autoantibody titers that correlated with renal autoimmune pathophysiology in murine gnotobiotic lupus models and with disease activity in patients with SLE. These studies elucidate cellular mechanisms of how a translocating gut pathobiont induces systemic human T cell- and B cell-dependent autoimmune responses and provide a framework for developing host- and microbiota-derived biomarkers and targeted therapies in autoimmune diseases.

An abnormal increase in CD26(-)CD28(-) cytotoxic effector CD4 and CD8 T cell populations in patients with systemic lupus erythematosus

CD26 is a human T cell costimulatory molecule as well as a T cell subset marker, and the increase of CD26+ T cells in inflamed tissues and peripheral blood has been reported in diverse autoimmune diseases. In contrast, our group has previously shown that levels of circulating CD26+ T cells are decreased in patients with systemic lupus erythematosus (SLE), although the role of reduced CD26 T cell surface expression in SLE pathology remains to be elucidated. In the present study, we conducted CD26-based T cell subset analyses utilizing peripheral blood mononuclear cells from 57 SLE patients and 31 healthy adult volunteers. We show that the increase in the CD26(-) T cell population reflects the abnormal expansion of CD26(-)CD28(-) cytotoxic subsets of both CD8 T cells and CD4 T cells in SLE patients. Single-cell RNA sequencing analysis of the CD26(-)CD28(-) CD4 and CD8 T cell populations reveals unique characteristics with similarities to natural killer T cells. In addition, the level of CD26(-)CD28(-) T cells is increased in some active-stage SLE patients with renal manifestation. Meanwhile, the effect of prednisolone treatment on these populations varies from patient to patient, with levels of these cytotoxic effector populations still being elevated in some inactive-stage SLE patients. Taken together, our data suggest that analysis of these populations in SLE may be a useful tool to classify this markedly heterogeneous condition.

Therapeutic application of circular RNA aptamers in a mouse model of psoriasis

Efforts to advance RNA aptamers as a new therapeutic modality have been limited by their susceptibility to degradation and immunogenicity. In a previous study, we demonstrated synthesized short double-stranded region-containing circular RNAs (ds-cRNAs) with minimal immunogenicity targeted to dsRNA-activated protein kinase R (PKR). Here we test the therapeutic potential of ds-cRNAs in a mouse model of imiquimod-induced psoriasis. We find that genetic supplementation of ds-cRNAs leads to inhibition of PKR, resulting in alleviation of downstream interferon-α and dsRNA signals and attenuation of psoriasis phenotypes. Delivery of ds-cRNAs by lipid nanoparticles to the spleen attenuates PKR activity in examined splenocytes, resulting in reduced epidermal thickness. These findings suggest that ds-cRNAs represent a promising approach to mitigate excessive PKR activation for therapeutic purposes.

How (Ultra-)Rare Gene Variants Improve Our Understanding of More Common Autoimmune and Inflammatory Diseases

The aim of this study was to explore the impact of rare and ultra-rare genetic variants on the understanding and treatment of autoimmune and autoinflammatory diseases with a focus on systemic lupus erythematosus (SLE) and Behçet syndrome. This review summarizes current research on the monogenic causes of SLE and Behçet syndrome, highlighting the various pathways that can be responsible for these unique phenotypes. In monogenic SLE, the identification of complement and DNASE1L3 deficiencies has elucidated mechanisms of apoptotic body accumulation and extracellular nucleic acid sensing. Type I interferonopathies underline the specific role of DNA/RNA sensing and the interferon overexpression in the development of systemic autoimmunity. Other significant genetic defects include Toll-like receptor hypersignaling and JAK/STATopathies, which contribute to the breakdown of immune tolerance. To date, genetic defects directly affecting B and T cell biology only account for a minority of identified causes of monogenic lupus, highlighting the importance of a tight regulation of mechanistic target of rapamycin and RAS (Rat sarcoma GTPase)/MAPK (mitogen-activated protein kinase) signaling in lupus. In Behçet syndrome, rare variants in TNFAIP3, RELA, and NFKB1 genes have been identified, underscoring the importance of NF-κB overactivation. Additional monogenic diseases such as ELF4, WDR1 mutations and trisomy 8 further illustrate the genetic complexity of this condition. Observations from genetic studies in SLE and Behçet syndrome highlight the complexity of systemic inflammatory diseases in which distinct molecular defects caused by single-gene mutations can promote lupus or Behçet syndromes, often unrecognizable from their genetically complex "classical" forms. Insights gained from studying rare genetic variants enhance our understanding of immune function in health and disease, paving the way for targeted therapies and personalized medicine.

Opportunities and limitations of B cell depletion approaches in SLE

B cell depletion with rituximab, a chimeric monoclonal antibody that selectively targets B cells by binding CD20, has been used off label in severe and resistant systemic lupus erythematosus (SLE) for over two decades. Several biological mechanisms limit the efficacy of rituximab, including immunological reactions towards the chimeric molecule, increased numbers of residual B cells, including plasmablasts and plasma cells, and a post-treatment surge in B cell-activating factor (BAFF) levels. Consequently, rituximab induces remission in only a proportion of patients, and safety issues limit its use. However, the use of rituximab has established the value of B cell depletion strategies in SLE and has guided the development of several improved B cell depletion therapies for SLE. These include enhanced monoclonal antibodies, modalities that redirect the specificity of patient T cells using chimeric antigen receptor T cells or bispecific T cell engagers, and combination treatment that simultaneously inhibits the BAFF pathway. In this Review, we consider evidence gathered from over two decades of using rituximab in SLE and examine how B cell depletion therapies could be further optimized to achieve immunological and clinical efficacy. In addition, we discuss the prospects of B cell depletion strategies for personalized treatment in SLE based on genetic research and studies in pre-symptomatic individuals.

Dose effect of corticosteroids on peripheral lymphocyte profiles in patients with systemic lupus erythematosus

OBJECTIVE

To investigate the dose effect of methylprednisolone (MP) on peripheral lymphocyte profiles in patients with systemic lupus erythematosus (SLE). This study investigated the impact of varied MP doses on peripheral lymphocyte subtypes in SLE patients.

METHODS

We conducted a prospective study involving 51 SLE patients, categorized into four groups (40 mg/day, 80 mg/day, 500 mg/day, and 1000 mg/day) based on the administered MP dosage during hospitalization. We analyzed the lymphocyte count and proportion in peripheral blood, along with their subpopulations, before and after MP treatment using the paired Mann-Whitney U test.

RESULTS

Treatment with a clinically rational dose of MP (40 mg/day or 80 mg/day) resulted in increased lymphocyte counts, encompassing total lymphocytes, T cells, CD4 + T cells, regulatory T cells (Treg), and effector T cells (Teff) in the short term. Conversely, the counts of these cells decreased with pulse MP (500 mg/day or 1000 mg/day). The percentage of Treg cells and the Treg/Teff ratio increased following 40 mg or 80 mg MP/day treatment, whereas they decreased after pulse therapy. A gradual augmentation in the count and percentage of Treg cells was observed during continuous administration of 40 mg or 80 mg MP/day for 1 week, while in patients receiving pulse therapy, Treg cells tended to decrease during the therapy but rapidly recovered upon MP reduction.

CONCLUSION

Lower doses of MP in the short term increased Treg cells, inhibiting systemic inflammation in SLE. High-dose pulse therapy exhibited a suppressive effect on Tregs. Key Points • Different dosages of methylprednisolone have variable effects on peripheral lymphocyte subsets. • Methylprednisolone pulse therapy leads to a rapid decrease in Treg cells. • Clinically rational methylprednisolone treatment leads to an increase in Treg cells.

Pharmacological Mechanism of Chinese Medicine in Systemic Lupus Erythematosus: A Narrative Review

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder affecting multiple systems, characterized by the development of harmful autoantibodies and immune complexes that lead to damage in organs and tissues. Chinese medicine (CM) plays a role in mitigating complications, enhancing treatment effectiveness, and reducing toxicity of concurrent medications, and ensuring a safe pregnancy. However, CM mainly solves the disease comprehensively through multi-target and multi-channel regulation process, therefore, its treatment mechanism is often complicated, involving many molecular links. This review introduces the research progress of pathogenesis of SLE from the aspects of genetics, epigenetics, innate immunity and acquired immunity, and then discusses the molecular mechanism and target of single Chinese herbal medicine and prescription that are commonly used and effective in clinic to treat SLE.

Predictors of renal flares in systemic lupus erythematosus: a post-hoc analysis of four phase III clinical trials of belimumab

OBJECTIVE

The objective of this study was to identify predictors of renal flares in patients with SLE treated for active extra-renal disease.

METHODS

Data from four clinical trials of belimumab in SLE (BLISS-52, NCT00424476; BLISS-76, NCT00410384; BLISS-NEA, NCT01345253; BLISS-SC, NCT01484496) were used. Patients were assigned to belimumab or placebo on top of standard therapy. We investigated the performance of predictors of renal flares through weeks 52-76 using proportional hazards regression analysis.

RESULTS

Of 3225 participants, 192 developed at least one renal flare during follow-up, with the first occurring after a median time of 197 days. Current/former renal involvement [hazards ratio (HR): 15.4; 95% CI: 8.3-28.2; P < 0.001], low serum albumin levels (HR 0.9; 95% CI: 0.8-0.9; P < 0.001), proteinuria (HR: 1.6; 95% CI: 1.5-1.7; P < 0.001), and low C3 levels (HR: 2.9; 95% CI: 2.1-4.1; P < 0.001) at baseline appeared robust determinants of impending renal flares. Anti-dsDNA positivity yielded an increased hazard for renal flares (HR: 2.1; 95% CI: 1.4-3.2; P < 0.001), which attenuated after adjustments. Anti-Sm positivity was associated with renal flares in the placebo (HR: 3.7; 95% CI: 2.0-6.9; P < 0.001) but not in the belimumab subgroup, whereas anti-ribosomal P positivity was associated with renal flares in the belimumab subgroup only (HR: 2.8; 95% CI: 1.5-5.0; P = 0.001).

CONCLUSION

A history of renal involvement, high baseline proteinuria, hypoalbuminaemia, and C3 consumption were robust determinants of impending renal flares. In addition to anti-dsDNA, anti-Sm and anti-ribosomal P protein antibody positivity may have value in surveillance of renal SLE.

Exploring precision treatments in immune-mediated inflammatory diseases: Harnessing the infinite potential of nucleic acid delivery

Immune-mediated inflammatory diseases (IMIDs) impose an immeasurable burden on individuals and society. While the conventional use of immunosuppressants and disease-modifying drugs has provided partial relief and control, their inevitable side effects and limited efficacy cast a shadow over finding a cure. Promising nucleic acid drugs have shown the potential to exert precise effects at the molecular level, with different classes of nucleic acids having regulatory functions through varying mechanisms. For the better delivery of nucleic acids, safe and effective viral vectors and non-viral delivery systems (including liposomes, polymers, etc.) have been intensively explored. Herein, after describing a range of nucleic acid categories and vectors, we focus on the application of therapeutic nucleic acid delivery in various IMIDs, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, multiple sclerosis, asthma, ankylosing spondylitis, systemic lupus erythematosus, and uveitis. Molecules implicated in inflammation and immune dysregulation are abnormally expressed in a series of IMIDs, and their meticulous modulation through nucleic acid therapy results in varying degrees of remission and improvement of these diseases. By synthesizing findings centered on specific molecular targets, this review delivers a systematic elucidation and perspective towards advancing and utilization of nucleic acid therapeutics for managing IMIDs.

Why is it so difficult to understand why we don't understand human systemic lupus erythematosus? Contemplating facts, conflicts, and impact of "the causality cascade paradigm"

In attempts to understand systemic lupus erythematosus (SLE), we find ourselves in the intellectual cross-point between nosology, pathogenicity-oriented science, philosophy, empiricism, and qualified conjectures. A vital consequence in science theory is that scientific hypotheses that are not critically investigated are in danger of being transformed into scientific dogmas. This statement has consequences for this study. Two central problematic aspects are discussed. For the first, we have to consider new selection principles for classification criteria-implying integration of the causality principle. Second, central historical data must be implemented if we aim to understand SLE. These data comprise famous descriptions of distinct, dynamically changing DNA structures linked to the genetic machinery. These unique structures have since their discoveries decades ago mostly been ignored in SLE research. Likewise, inconclusive dogmatic data indicate that different glomerular ligands are recognized by nephritogenic anti-dsDNA antibodies-exposed chromatin fragments or inherent membrane ligands. These incongruent models have not been comparatively and systematically investigated. Three research areas will be critically discussed: (i) selection and role of SLE classification criteria, a process that must imply the causality principle; (ii) definition and impact of anti-dsDNA structure-specific antibodies; (iii) incongruent pathogenic models that account for lupus nephritis. A precise and critically important question is if SLE itself is a response to a dominant unified cause that initiates a cascade of downstream effects (criteria) or if SLE represents combined responses to a random interplay of multiple cause-effect events. These principally different explanations are formally not excluded or accepted today. Currently, SLE may be regarded as a disease with phenotypic diversity, independently segregated manifestations with unresolved etiologies that are not unique to a single SLE phenotype. The focus for the present discussion is basically how we, by critical hypotheses, can re-consider science-based selection of SLE classification criteria in order to delimitate and rationalize SLE. Classification criteria, autoimmunity, DNA structures, and anti-dsDNA antibodies are integrated aspects in this discussion.

Neutrophil extracellular traps as a potential marker of systemic lupus erythematosus activity

BACKGROUND

The heterogeneity of systemic lupus erythematosus (SLE) poses a significant challenge in identifying biomarkers for assessing disease activity. Currently, there is a paucity of established biomarkers capable of evaluating SLE flares. This study aimed to identify novel biomarkers that exhibit improved diagnostic accuracy in assessing SLE activity.

METHODS

A cross-sectional study was conducted at Zhongshan Hospital Xiamen University from August 2021 to April 2024,enrolling 118 patients with SLE, including 81 cases of active SLE, 50 cases of active lupus nephritis (LN) and 30 cases of active non-LN. The objective was to evaluate the diagnostic accuracy of novel biomarker called Neutrophil Extracellular Traps(NETs) for SLE activity and analyze its correlations with conventional biomarkers such as complement C3, C4, and anti-dsDNA.

RESULTS

Serum NETs levels were significantly elevated in patients with active SLE and active LN(P < 0.001). Furthermore, positive correlations were observed between NETs levels and disease activity score based on Systemic Lupus Erythematosus Disease Activity Index-2 K (SLEDAI-2 K) (r = 0.64, P < 0.001), as well as anti-dsDNA antibody (r = 0.54, P < 0.001).Conversely, the NETs levels were negativity correlated with complement C3 concentration (r = -0.50, P < 0.001), as well as C4 concentration (r = -0.34,P < 0.001). Univariate and multivariate analysis revealed two biomarkers performed statistical significance: NETs (OR = 6.802, 95 %CI: 2.414-19.167,P < 0.001) and anti-dsDN A(OR = 3.95,95 %CI:1.582-9.864, P = 0.003). NETs had the highest AUC of 0.82(P < 0.001), with a cut-off at 515.47 ng/L demonstrating 61.63 % sensitivity and 96.87 % specificity. For the active LN group, the AUC was found to be 0.97 (P < 0.001), with a cutoff value of 515.47 ng/L, sensitivity of 100 %, and specificity of 59.76 %. Moreover, the active non-LN group had AUC of 0.70 (P = 0.007), with the same cutoff value, sensitivity of 89.61 %, and specificity of 51.61 %.

CONCLUSION

In contrast to conventional laboratory markers, serum NETs represent a novel diagnostic marker for assessing disease activity in SLE, demonstrating promising potential for clinical application.

The TLR7/9 adaptors TASL and TASL2 mediate IRF5-dependent antiviral responses and autoimmunity in mouse

Endosomal nucleic acid sensing by Toll-like receptors (TLRs) is central to antimicrobial immunity and several autoimmune conditions such as systemic lupus erythematosus (SLE). The innate immune adaptor TASL mediates, via the interaction with SLC15A4, the activation of IRF5 downstream of human TLR7, TLR8 and TLR9, but the pathophysiological functions of this axis remain unexplored. Here we show that SLC15A4 deficiency results in a selective block of TLR7/9-induced IRF5 activation, while loss of TASL leads to a strong but incomplete impairment, which depends on the cell type and TLR engaged. This residual IRF5 activity is ascribed to a previously uncharacterized paralogue, Gm6377, named here TASL2. Double knockout of TASL and TASL2 (TASLDKO) phenocopies SLC15A4-deficient feeble mice showing comparable impairment of innate and humoral responses. Consequently, TASLDKO mice fail to control chronic LCMV infection, while being protected in a pristane-induced SLE disease model. Our study thus demonstrates the critical pathophysiological role of SLC15A4 and TASL/TASL2 for TLR7/9-driven inflammatory responses, further supporting the therapeutic potential of targeting this complex in SLE and related diseases.

Interleukin-1 Receptor-Associated Kinase 4 (IRAK4) Degraders for Treating Inflammatory Diseases: Advances and Prospects

Interleukin-1 receptor-associated kinase 4 (IRAK4) is involved in various inflammation-related diseases. Both the kinase and scaffolding functions of IRAK4 initiate pro-inflammatory factor transcription and expression. The scaffolding function of IRAK4 is essential for Myddosome assembly and NF-κB activation. Conventional small-molecule inhibitors effectively inhibit the kinase function of IRAK4 but do not block its scaffolding function. Recently, various IRAK4 degraders have shown promising therapeutic potential in inflammatory diseases. The most advanced IRAK4-selective degrader, KT-474 (SAR444656), significantly reduced inflammatory biomarker levels in patients and demonstrated high safety and tolerability. This perspective introduces and discusses the physiological biology of IRAK4, its associated diseases, and the current development of IRAK4 degraders, thereby offering insights into future research directions.

Immunometabolism of Tregs: mechanisms, adaptability, and therapeutic implications in diseases

Immunometabolism is an emerging field that explores the intricate interplay between immune cells and metabolism. Regulatory T cells (Tregs), which maintain immune homeostasis in immunometabolism, play crucial regulatory roles. The activation, differentiation, and function of Tregs are influenced by various metabolic pathways, such as the Mammalian targets of rapamycin (mTOR) pathway and glycolysis. Correspondingly, activated Tregs can reciprocally impact these metabolic pathways. Tregs also possess robust adaptive capabilities, thus enabling them to adapt to various microenvironments, including the tumor microenvironment (TME). The complex mechanisms of Tregs in metabolic diseases are intriguing, particularly in conditions like MASLD, where Tregs are significantly upregulated and contribute to fibrosis, while in diabetes, systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA), they show downregulation and reduced anti-inflammatory capacity. These phenomena suggest that the differentiation and function of Tregs are influenced by the metabolic environment, and imbalances in either can lead to the development of metabolic diseases. Thus, moderate differentiation and inhibitory capacity of Tregs are critical for maintaining immune system balance. Given the unique immunoregulatory abilities of Tregs, the development of targeted therapeutic drugs may position them as novel targets in immunotherapy. This could contribute to restoring immune system balance, resolving metabolic dysregulation, and fostering innovation and progress in immunotherapy.

ADAR1 haploinsufficiency and sustained viral RdRp dsRNA synthesis synergize to dysregulate RNA editing and cause multi-system interferonopathy

Sensing of viral double-stranded RNA by MDA5 triggers abundant but transient interferon-stimulated gene (ISGs) expression. If dsRNA synthesis is made persistent by transgenically expressing a picornaviral RNA-dependent RNA polymerase (RdRp) in mice, lifelong MDA5 activation and marked, global ISG upregulation result. This confers robust protection from viral diseases but in contrast to numerous other chronic MDA5 hyperactivation states, the mice suffer no autoimmune consequences. Here we find they further confound expectations by being resistant to a strong autoimmunity (lupus) provocation. However, knockout of one allele of Adar , which by itself is also well-tolerated, breaks the protective state and results in a severe disease that resembles interferonopathies caused by MDA5 gain-of-function mutations. In Adar +/- RdRp transgenic mice, A-to-I editing is both dysregulated and increased (numbers of genes and sites). This dsRNA-driven, MDA5-wild type model establishes that viral polymerase-sourced dsRNA can drive interferonopathy pathogenesis and illuminates the autoimmunity preventing role of ADAR1, while the ADAR1-intact viral RdRp model distinctively uncouples chronic MDA5 hyperactivity and autoinflammatory disease.

Lipid metabolism in myeloid cell function and chronic inflammatory diseases

Immune cells adapt their metabolism in response to their differentiation and activation status to meet the energy demands for an appropriate immune response. Recent studies have elucidated that during immune cell metabolic reprogramming, lipid metabolism, including lipid uptake, de novo lipid synthesis and fatty acid oxidation, undergoes significant alteration, resulting in dynamic changes in the quantity and quality of intracellular lipids. Given that lipids serve as an energy source and structural components of cellular membranes, they have important implications for physiological function. Myeloid cells, which are essential in bridging innate and adaptive immunity, are sensitive to these changes. Dysregulation of lipid metabolism in myeloid cells can result in immune dysfunction, chronic inflammation and impaired resolution of inflammation. Understanding the mechanism by which lipids regulate immune cell function might provide novel therapeutic insights into chronic inflammatory diseases, including metabolic diseases, autoimmune diseases and cancer. (143 words).

Lactobacillus rhamnosus LC-STH-13 ameliorates the progression of SLE in MRL/lpr mice by inhibiting the TLR9/NF-κB signaling pathway

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease often treated with glucocorticoids, which can lead to complications such as osteoporosis and an increased infection risk. Hence, identifying safe and effective treatment strategies is crucial. Lactobacillus has shown promise in improving immune disorders. We investigated Lactobacillus rhamnosus LC-STH-13 for its probiotic properties. Female MRL/lpr mice, prone to lupus, were used to assess its impact on SLE development. The results showed that the intervention with L. rhamnosus LC-STH-13 significantly reduced the level of circulating anti-autoantibodies (p < 0.05) and rebalanced Th17/Treg cells (p < 0.05). Kidney tissue analysis revealed reduced immune cell infiltration and immune complex deposition in glomeruli. L. rhamnosus LC-STH-13 mitigated kidney inflammation via the TLR9/NF-κB pathway (p < 0.05) and attenuated complement-induced renal damage (p < 0.05). Furthermore, 16S rRNA sequencing data analysis indicated that L. rhamnosus LC-STH-13 can restore intestinal microecological imbalance caused by the development of SLE. These findings suggested that L. rhamnosus LC-STH-13 improves the development of SLE by regulating the TLR9/NF-κB pathway and intestinal microbiota, offering a foundation for exploring safe and effective treatments.

Immunopeptidomics for autoimmunity: unlocking the chamber of immune secrets

T cells mediate pathogenesis of several autoimmune disorders by recognizing self-epitopes presented on Major Histocompatibility Complex (MHC) or Human Leukocyte Antigen (HLA) complex. The majority of autoantigens presented to T cells in various autoimmune disorders are not known, which has impeded autoantigen identification. Recent advances in immunopeptidomics have started to unravel the repertoire of antigenic epitopes presented on MHC. In several autoimmune diseases, immunopeptidomics has led to the identification of novel autoantigens and has enhanced our understanding of the mechanisms behind autoimmunity. Especially, immunopeptidomics has provided key evidence to explain the genetic risk posed by HLA alleles. In this review, we shed light on how immunopeptidomics can be leveraged to discover potential autoantigens. We highlight the application of immunopeptidomics in Type 1 Diabetes (T1D), Systemic Lupus Erythematosus (SLE), and Rheumatoid Arthritis (RA). Finally, we highlight the practical considerations of implementing immunopeptidomics successfully and the technical challenges that need to be addressed. Overall, this review will provide an important context for using immunopeptidomics for understanding autoimmunity.

Type I interferon-stimulated genes predict clinical response to belimumab in systemic lupus erythematosus

The type I interferon (IFN-I) response is crucial in systemic lupus erythematosus (SLE). The mRNA level of interferon-stimulated genes (ISGs) is widely used for evaluating the activity of IFN in SLE. However, the character of ISGs in belimumab-treated SLE patients has not be reported. In this study, we enrolled 53 SLE patients undergoing belimumab treatment and assessed their clinical responses at 3, 6, and 12 months. The expression levels of 25 ISGs in Peripheral blood mononuclear cells (PBMCs) were quantified at baseline and at 3 months using quantitative real-time PCR. Using Least absolute shrinkage and selection operator (LASSO)-logistic regression, five genes (CXCL10, EPSTI1, HECR6, IFI27, IFIH1) were identified to predict belimumab efficacy. The IFN signature score, a multivariate logistic regression model based on the change rates of these genes, positively predicted the SLE responder index (SRI) at 12 months, with an area under curve of 0.940 in receiver operating characteristic and favorable outcomes in decision curve analysis. Patients with an IFN signature score ≥0 had higher SRI response rates, better clinical markers (including SLE disease activity index 2000 scores, anti-dsDNA, IgG levels, daily doses of prednisone, and higher complement C3 and C4 levels), and faster B cell decline than those with scores <0. In conclusion, after 3 months of belimumab treatment, the expression levels of IFN-I-inducible genes varied, and the IFN signature score reliably forecasted the SRI response at 6 and 12 months.

Mitochondria dysfunction: A trigger for cardiovascular diseases in systemic lupus erythematosus

Cardiovascular disease (CVD), including pericarditis, myocarditis, sudden cardiac death, coronary heart disease, and stroke, are leading contributors to morbidity and mortality in systemic lupus erythematosus (SLE) patients. Emerging evidence highlights mitochondrial dysfunction as a key driver of cardiovascular pathology in SLE, with impaired oxidative phosphorylation, altered membrane potential, and disrupted metabolic processes promoting oxidative stress, inflammatory activation, and endothelial dysfunction. This review critically examines mitochondrial contributions to CVD in SLE, comparing these mechanisms with those in non-SLE CVD to highlight SLE-specific mitochondrial vulnerabilities. Furthermore, we discuss preclinical and clinical findings supporting mitochondrial pathways as potential therapeutic targets, aiming to bridge gaps in current understanding and outline future research directions. By synthesizing current knowledge of mitochondrial dysregulation, this review proposes therapeutic strategies to improve cardiovascular outcomes and advance patient care in SLE.

Comparative efficacy and safety of different recommended doses of telitacicept in patients with systemic lupus erythematosus in China: a systematic review and meta-analysis

Background

Telitacicept, a new biological agent, was approved in China for treating systemic lupus erythematosus (SLE) in 2021. Its optimal dosing for treating SLE remains unclear. Therefore, the aim of this meta-analysis is to evaluate the efficacy and safety of various telitacicept doses in SLE treatment.

Methods

PubMed, EMBASE, Cochrane libraries, Web of science, China National Knowledge Infrastructure (CNKI), VIP, Wanfang, and Sinomed were searched for the controlled trials that studied the efficacy and safety of telitacicept on SLE patients from their initiation to April 30, 2024. The analysis included three randomized controlled trials (RCT) with 606 participants. We used fixed-effects models for meta-analyses and the risk ratios (RRs) and corresponding 95% confidence intervals (CIs) to evaluate the effectiveness and safety. Heterogeneity was assessed and quantified using I2.

Results

All telitacicept dosages (80 mg, 160 mg, 240 mg) significantly improved SLE Responder Index 4 (SRI4) responses compared to the control group (RR = 2.20, 95%CI:1.50-3.21, p < 0.0001; RR = 2.18, 95%CI: 1.82-2.62, p < 0.00001; RR = 2.44, 95%CI: 1.67-3.56, p < 0.00001, respectively). The 80 mg, 160 mg, and 240 mg groups also showed better improvement on SELENA-SLE Disease Activity Index (SELENA-SLEDAI) scores (RR = 1.63, 95%CI: 1.23-2.17, p = 0.0008; RR = 1.72, 95%CI: 1.45-2.04, p < 0.00001; RR = 1.73, 95%CI: 1.30-2.30, p = 0.0002, respectively) and Physician Global Assessment (PGA) scores (RR = 1.25, 95%CI: 1.09-1.44, p = 0.002; RR = 1.39, 95%CI: 1.25-1.55, p < 0.00001; RR = 1.24, 95%CI: 1.09-1.42, p = 0.002, respectively). Furthermore, 160 mg group exhibited higher British Isles Lupus Assessment Group (BILAG) score than the control group (RR = 1.11, 95%CI: 1.01-1.22, p = 0.03). As for security, 160 mg telitacicept group had higher incidence of adverse events (AEs) than the control group (RR = 1.10, 95%CI: 1.03-1.18, p = 0.007).

Conclusion

Telitacicept combined with standard therapy presents potential benefits but there are certain safety concerns with certain dosages of telitacicept, warranting further investigation for optimal dosing strategies in SLE management.

Systematic review registration

INPLASY.COM, identifier INPLASY202440101.

Comparative Analysis of CXCR5 Circulating DNA Methylation Levels in Autoimmune Rheumatic Diseases

OBJECTIVE

To assess CXC chemokine receptor 5 (CXCR5) circulating DNA methylation differences in autoimmune rheumatic diseases and their relation with clinical features.

METHODS

Targeted methylation sequencing was performed using peripheral blood from 164 rheumatoid arthritis (RA), 30 systemic lupus erythematosus (SLE), 30 ankylosing spondylitis (AS), 30 psoriatic arthritis (PsA), 24 Sjögren's syndrome (SS) patients, and 30 healthy controls (HC).

RESULTS

Significant differences in CXCR5 cg19599951 methylation were found between RA and HC, as well as AS and SLE. RA patients exhibited higher methylation than HC and AS (p < 0.01) but lower than SLE (p < 0.05). SLE patients showed higher methylation compared to HC, AS, and PsA (p < 0.001, 0.01, and 0.05, respectively). No significant differences were found in patients with SS compared to other autoimmune diseases and HC. Methylation at cg19599951_103 (r = 0.17, p < 0.05) and cg19599951_209 (r = 0.22, p < 0.01), along with the CC haplotype (r = 0.21, p < 0.01), showed significant positive correlations with erythrocyte sedimentation rate (ESR), while the CT (r = -0.27, p < 0.001) and TT haplotypes (r = -0.19, p < 0.05) were negatively correlated. For C-reactive protein (CRP), methylation at cg19599951_103 (r = 0.29, p < 0.001) and cg19599951_209 (r = 0.33, p < 0.0001), and the CC haplotype (r = 0.34, p < 0.0001) was positively correlated, whereas the CT (r = -0.36, p < 0.0001) and TT (r = -0.30, p < 0.0001) haplotypes were negatively correlated. Significant negative correlations were observed between the CT haplotype and rheumatoid factor (r = -0.25, p < 0.01), and anti-citrullinated protein antibody (r = -0.20, p < 0.05). No significant correlations were found in patients with SLE, AS, and SS. Receiver operating characteristic analysis showed CXCR5 methylation could classify patients with RA versus those with AS (AUC: 0.624-0.967).

CONCLUSION

Differential circulating CXCR5 methylation levels were observed in autoimmune rheumatic diseases, which correlated with inflammatory mediators in RA and may serve as potential biomarkers for RA diagnosis.

Improved diagnosis of systemic lupus erythematosus with human-derived double-stranded DNA antigen

Anti-double-stranded DNA antibodies (anti-dsDNA) serve as a crucial serological indicator for systemic lupus erythematosus (SLE). Chemiluminescent immunoassay (CIA) is mainly used in clinical diagnosis of SLE, but suffers from low specificity, partially because the use of dsDNA antigens of varied sources in current CIA kits that sometimes led to controversial results. On the basis that anti-dsDNA in healthy individuals tend to selectively bind with dsDNA originating from pathogens, whereas pathogenic anti-dsDNA in SLE patients bind all forms of dsDNA, here we proposed the use of dsDNA fragment derived from human genome as antigen (synthesized via PCR using the human genomic DNA as the template). A magnetic bead-based immunofluorescence assay (IFA) was thus developed for SLE diagnosis, which exhibited improved sensitivity and specificity over CIA using the WHO reference reagent (15/174) as standard. For clinical serum sample analysis (n = 590), IFA exhibited an accuracy of 71.9% that was higher than CIA (65.3%). Crucially, the IFA results exhibited stronger correlations with the activity of SLE, renal involvement, and its prognosis. Besides the improved clinical diagnosis, the proposed IFA also holds great promise in assay standardization due to the high homogeneity of the synthetic dsDNA.

Association between peripheral activated naive and double negative 2 B-cell subsets and clinical parameters in lupus nephritis patients

Altered composition of B-cell compartments is a known feature in patients with systemic lupus erythematosus (SLE). However, deep characterisation of B-cell subsets and their relation to clinical manifestations and disease activity in patients is limited. In this study, we analysed peripheral B-cell subsets phenotype in SLE (n = 35) and healthy controls (HCs, n = 15) by spectral flow cytometry. Disease activity was stratified as inactive (SLEDAI-2 K score 0, n = 2), mild (SLEDAI-2 K score 1-5, n = 12), moderate (SLEDAI-2 K score 6-10, n = 6) or high (SLEDAI-2 K > 10, n = 15). An elevated proportion of activated naive (aNAV), double negative 2 (DN2) and plasmablasts (PB) was observed in patients with high disease activity, compared to other groups of patients and HCs. An upregulation of BTLA was found on both aNAV and DN2 and shifted to lower levels with increasing disease activity. In lupus nephritis (LN) patients (n = 21), aNAV B-cells were especially expanded and positively correlated with DN2 (r = 0.5, p = 0.019) and PB (r = 0.43, p = 0.048). Also, correlation was observed between DN2 and PB (r = 0.6, p = 0.003). Moreover, aNAV frequencies positively correlated with SLEDAI-2 K score, and negatively with the complement fractions C3 and C4. Further, aNAV, DN2 and PB were more expanded in association with positive anti-dsDNA antibodies, rather than other antibody specificities (anti-Sm). These data suggest roles of extrafollicular B cells as key players in disease development of LN. Their association with presence of anti-dsDNA antibodies may indicate their value as candidate biomarkers of kidney involvement in SLE.

Identification of Novel Hub Genes Associated with Inflammation and Autophagy in Astragaloside Membranaceus ameliorates Lupus Nephritis by Bioinformatics Analysis and Molecular Dynamics Simulation

BACKGROUND

Lupus nephritis is an autoimmune disease, and its pathogenesis involves inflammation and autophagy disorders. Studies have demonstrated that Astragalus membranaceus can effectively suppress the progression of LN, but the underlying therapeutic target is still unclear.

OBJECTION

This study aimed to investigate the therapeutic target whereby AM ameliorates LN.

METHOD

We downloaded AM and LN-related chips from the TCMSP and GEO databases, respectively. We selected the two compound targets for the subsequent analysis via WGCNA, and constructed protein interaction networks of compound targets and determined the core targets. GO, KEGG analyses were conducted on compound targets to identify enriched functional and genomic pathways. The core genes were further validated in clinical and external datasets. Molecular docking of AS with the core targets was performed using the AutoDock software, and molecular dynamics simulation was conducted for the optimal core protein ligand obtained by molecular docking by Gromacs 2020.6 software.

RESULT

We obtained 10 core targets, namely IL-1β, EGF, CCND1, CASP3, STAT1, PTGS2, PPARγ, AR, CXCL10, and KDR, from the 24 compound targets identified. The results of the GO enrichment analysis mainly included cell growth regulation. The results of the KEGG enrichment analysis showed that 7 out of 23 valid targets were significantly enriched in the mitogen-activated protein kinase pathway (p < 0.01). Combined with the clinical datasets, we found that IL-1β, EGF, CCND1, CASP3, STAT1, PTGS2, and PPARγ have high diagnostic values for LN. In the validation dataset, all the core targets were significantly differentially expressed, except for EGF deletion. The molecular docking and molecular dynamics simulation results showed that AM and IL- 1β, CASP3, STAT1, and PPARγ all had binding energies < -5 kJ·mol-1 and good binding properties.

CONCLUSION

IL-1β, CASP3, STAT1, and PPARγ could be potential biomarkers and therapeutic targets in AM ameliorates LN.

The SLE Conundrum: A Comprehensive Analysis of Pathogenesis, Recent Developments, and the Future of Therapeutic Interventions

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder with multifactorial interactions among various susceptibility factors. Significant strides have been made in understanding the pathogenesis of SLE, leading to the development of targeted therapies and the exploration of alternative treatments. The approval of new therapies has expanded patient treatment options, and ongoing clinical trials promise to enhance the treatment landscape further. The future of SLE treatment lies in personalized, targeted therapies that minimize side effects and improve patient outcomes. This review comprehensively analyzes SLE's current status and prospects based on recent studies, patents, clinical trials, and formulations. Continued research and clinical trials are crucial to uncovering new therapeutic options and ultimately transforming the treatment landscape for SLE. With sustained efforts and advancements in medical science, we can offer a better quality of life and improved survival rates for SLE patients.

Characterization of Dendritic Cells and Myeloid-Derived Suppressor Cells Expressing Major Histocompatibility Complex Class II in Secondary Lymphoid Organs in Systemic Lupus Erythematosus-Prone Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by self-antibody production and widespread inflammation affecting various body tissues. This disease is driven by the breakdown of immune tolerance, which promotes the activation of autoreactive B and T cells. A key feature of SLE is dysregulation in antigen presentation, where antigen-presenting cells (APCs) play a central role in perpetuating immune responses. Dendritic cells (DCs) are highly specialized for antigen presentation among APCs. At the same time, myeloid-derived suppressor cells (MDSCs) can also express MHC-II molecules, although their role in SLE is less understood. Utilizing the SLE model, MRL/MpJ-Faslpr/J, we determined the presence of different phenotypes of DCs and MDSCs expressing MHC-II in secondary lymphoid organs, along with the gene expression of ICOSL, CD80 and CD86 in the spleen. Our study determined that the most abundant population of APCs in secondary lymphoid organs corresponds to cDC CD103-CD11b+ MHC-II+ throughout SLE development. Additionally, ICOSL expression increased over time, becoming more preponderant in week 16 in the SLE model, which could indicate that it is a crucial pathway for the development and progression of the pathology. In week 16, we observed a positive correlation between M-MDSC MHC-II and IFN-γ-producing CD4+ T cells.

The advent of chimeric antigen receptor T Cell therapy in recalibrating immune balance for rheumatic autoimmune disease treatment

CAR-T cell therapy, a cutting-edge cellular immunotherapy with demonstrated efficacy in treating hematologic malignancies, also exhibits significant promise for addressing autoimmune diseases. This innovative therapeutic approach holds promise for achieving long-term remission in autoimmune diseases, potentially offering significant benefits to affected patients. Current targets under investigation for the treatment of these conditions include CD19, CD20, and BCMA, among others. However, CAR-T therapy faces difficulties such as time-consuming cell manufacturing, complex and expensive process, and the possibility of severe adverse reactions complicating the treatment, etc. This article examines CAR-T therapy across various rheumatic autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren's syndrome (SS), systemic sclerosis (SSc), antisynthetase syndrome (ASS), and ANCA-associated vasculitis (AAV), highlighting both therapeutic advancements and ongoing challenges.

Clinical Potential of Misshapen/NIKs-Related Kinase (MINK) 1-A Many-Sided Element of Cell Physiology and Pathology

Misshapen/NIKs-related kinase (MINK) 1 belongs to the mammalian germinal center kinase (GCK) family. It contains the N-terminal, conserved kinase domain, a coiled-coil region, a proline-rich region, and a GCK, C-terminal domain with the Citron-NIK-Homology (CNH) domain. The kinase is an essential component of cellular signaling pathways, which include Wnt signaling, JNK signaling, pathways engaging Ras proteins, the Hippo pathway, and STRIPAK complexes. It thus contributes to regulating the cell cycle, apoptosis, cytoskeleton organization, cell migration, embryogenesis, or tissue homeostasis. MINK1 plays an important role in immunological responses, inhibiting Th17 and Th1 cell differentiation and regulating NLRP3 inflammasome function. It may be considered a link between ROS and the immunological system, and a potential antiviral target for human enteroviruses. The kinase has been implicated in the pathogenesis of sepsis, rheumatoid arthritis, asthma, SLE, and more. It is also involved in tumorigenesis and drug resistance in cancer. Silencing MINK1 reduces cancer cell migration, suggesting potential for new therapeutic approaches. Targeting MINK1 could be a promising treatment strategy for patients insensitive to current chemotherapies, and could improve their prognosis. Moreover, MINK1 plays an important role in the nervous system and the cardiovascular system development and function. The modulation of MINK1 activity could influence the course of neurodegenerative diseases, including Alzheimer's disease. Further exploration of the activity of the kinase could also help in gaining more insight into factors involved in thrombosis or congenital heart disease. This review aims to summarize the current knowledge on MINK1, highlight its therapeutic and prognostic potential, and encourage more studies in this area.

FASN contributes to the pathogenesis of lupus by promoting TLR-mediated activation of macrophages and dendritic cells

Hyper-activations of monocytes/macrophages and dendritic cells (DCs) contribute to the pathogenesis of various autoimmune diseases, such as systemic lupus erythematosus (SLE). Fatty acid synthase (FASN) is essential for the de novo synthesis of long-chain fatty acids, which play a key role in controlling the activation, differentiation, and function of immune cells. However, the role of FASN in regulating the activations of monocytes/macrophages and DCs has not been studied. In this study, we investigated the involvement of the FASN in modulating the activations of macrophages and DCs, as well as the pathogenesis of SLE. Importantly, we observed a significant upregulation of FASN expression in monocytes and DCs from patients with SLE. This increase is strongly correlated with disease severity and activation status of the immune cells. Furthermore, overexpression of FASN significantly boosts the TLR4/7/9-mediated activation of macrophages and DCs, while knockdown of FASN markedly inhibits this activation. Notably, knockdown of FASN alleviates TLR7 agonist imiquimod (IMQ)-induced lupus in mice and the activation of macrophages and DCs. It makes more sense that pharmaceutical targeting of FASN by using TVB-2640 significantly alleviates IMQ-induced lupus in mice and the activation of macrophages and DCs, as well as in spontaneous lupus MRL/lpr mice. Thus, FASN contributes to the TLRs-mediated activation of macrophages and DCs, as well as the pathogenesis of SLE. More importantly, FASN inhibitor TVB-2640 is expected to be an effective drug in the treatment of SLE.

Trained innate immunity in response to nuclear antigens in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease directed against nuclear antigens, including those derived from apoptotic microparticles (MPs) and neutrophil extracellular traps (NETs). Here we investigated whether nuclear autoantigens can induce trained immunity in SLE patients. Trained immunity is a de facto innate immune memory elicited by an initial stimulus that induces a more vigorous long-term inflammatory response to subsequent stimuli. Isolated monocytes were stimulated with SLE-typical nuclear antigens, neutrophil extracellular traps (NETs), and apoptotic microparticles (MPs) or plasma from SLE patients. After five days of rest, cells were restimulated with Toll-like receptor (TLR) agonists, and cytokine production was measured using ELISA. Functional, transcriptomic and epigenetic changes in monocytes from SLE patients were evaluated by ex vivo stimulations, flow cytometric analysis, RNA sequencing, and chromatin immunoprecipitation (ChIP) sequencing for histone 3 lysine 4 trimethylation. We found that in vitro, both MPs and NETs, as well as plasma from SLE patients, can induce trained immunity. Furthermore, circulating monocytes from SLE patients produce increased levels of pro-inflammatory cytokines after stimulation with TLR ligands, indicating trained immunity. This is accompanied by deregulation in histone 3 lysine 4 trimethylation and increased expression of metabolism and inflammation-related genes. Our findings demonstrate that trained immunity can develop against nuclear antigens and that trained immunity is involved in the immunological dysregulation in SLE patients.

Subchronic intranasal lipopolysaccharide exposure induces pulmonary autoimmunity and glomerulonephritis in NZBWF1 mice

Lupus, a systemic autoimmune disease shaped by gene-environment interplay, often progresses to endstage renal failure. While subchronic systemic exposure to bacterial lipopolysaccharide (LPS) triggers autoimmunity and glomerulonephritis in lupus-prone mice, it is unknown if inhaling LPS, which is common in certain occupations, can similarly trigger lupus. Here we determined how subchronic intranasal (IN) LPS instillation influences autoimmunity and glomerulonephritis development in lupusprone NZBWF1 female mice. Briefly, mice were IN-instilled with vehicle or E. coli LPS (0.8 μg/g) twice weekly for 5 wk, followed by necropsy. For systemic comparison, additional cohorts of mice were injected with LPS intraperitoneally (IP) using identical doses/timing. Lungs were assessed for inflammatory and autoimmune responses and then related to systemic autoimmunity and glomerulonephritis. IN/LPS exposure induced in the lung: i) leukocyte infiltration, ii)mRNA signatures for cytokines, chemokines, IFN-regulated, and cell death-related genes, iii) ectopic lymphoid tissue formation, and iv)diverse IgM and IgG autoantibodies (AAbs). Pulmonary effects coincided with enlarged spleens, elevated plasma IgG AAbs, and inflamed IgG-containing kidney glomeruli. In contrast, IP/LPS treatment induced systemic autoimmunity and glomerulonephritis without pulmonary manifestations. Taken together, these preclinical findings suggest the lung could serve as a critical nexus for triggering autoimmunity by respirable LPS in genetically predisposed individuals.

Partial long-term clinical improvement after a BCG challenge in systemic lupus erythematosus-prone mice

Systemic Lupus Erythematosus (SLE) is an autoimmune disorder that causes a breakdown of immune tolerance. Current treatments mainly involve general immunosuppression, increasing the risk of infections. On the other hand, Bacillus Calmette-Guérin (BCG) has been investigated as a potential therapy for autoimmune diseases in recent years, prompting an ongoing investigation. This study aimed to evaluate the effect of BCG vaccination on early and late clinical presentation of SLE in a murine disease model. MRL/MPJ-Faslpr mice were immunized with BCG or treated with PBS as a control. The progress of the disease was evaluated at 27 days post-immunization (dpi) (early) and 56 dpi (late). Clinical parameters and proteinuria were monitored. Blood samples were collected for measurement of antinuclear antibodies (ANAs), anti-double-stranded DNA (anti-dsDNA), and cytokine determination was performed using ELISA. Samples collected from mice were analyzed by flow cytometry and histopathology. We observed a clinical improvement in BCG-treated mice, reduced proteinuria in the latter stages of the disease, and decreased TNF-α. However, BCG did not elicit significant changes in ANAs, anti-dsDNA, histopathological scores, or immune cell infiltration. BCG was only partially beneficial in an SLE mouse model, and further research is needed to determine whether the immunity induced by this vaccine can counteract lupus's autoimmune response.

Characterization of systemic lupus erythematosus subtypes using cluster analysis: insights from lymphocyte subpopulations

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, in which lymphocyte subsets were dysregulated. Incorporating lymphocyte subpopulations in cluster analysis offers a pathway for personalized and precise treatment, targeting specific abnormalities for more effective management.

METHODS

We conducted Gaussian clustering analysis on clinical data, serological data, urine test results, and lymphocyte subpopulations for SLE patients hospitalized from September 2008 to December 2019.

RESULTS

A total of 1863 SLE patients from Xi'Jing Hospital were included. After excluding those without complete assessments, 1281 patients underwent flow cytometry for lymphocyte subsets. Five SLE clusters emerged: Cluster 1 with severe kidney involvement, high SLEDAI scores, and infection rates, often accompanied by rashes and edema; cluster 2 with high urinary protein but better renal function; cluster 3 with normal lymphocyte count and low positive antibodies; cluster 4 with frequent psychiatric symptoms and pulmonary arterial hypertension (PAH); and cluster 5 with fever, arthritis, hematologic involvement, and high IgG levels despite decreased B cells.

CONCLUSION

All enrolled SLE patients were ultimately categorized into five distinct clinical phenotype groups, with lymphocyte testing being meaningful for patient stratification. This finding shed light on the intricate heterogeneity of SLE, emphasizing the need for a personalized medicine approach. Targeting specific abnormalities in lymphocyte subsets holds promise for more effective and precise management of SLE. Key Points • A comprehensive analysis of SLE patients, including lymphocyte subpopulations, revealed five distinct clusters with varying clinical characteristics, emphasizing the heterogeneity of the disease. • This heterogeneity underscores the need for a personalized medicine approach in SLE management, targeting specific lymphocyte subset abnormalities for more effective and precise treatment.

Multiple-dose pharmacokinetics of cenerimod and the effect of charcoal on its elimination

Cenerimod is a sphingosine-1-phosphate receptor 1 modulator that reduces tissue availability of circulating lymphocytes. The compound is in Phase 3 development for the treatment of systemic lupus erythematosus. Its pharmacokinetic properties are characterized by slow absorption and multiphasic elimination with a long terminal half-life (t½), potentially caused by enterohepatic circulation (EHC). In this trial in healthy participants, oral cenerimod 0.5 and 4 mg once daily was administered for 50 days, followed by oral administration of activated charcoal (ie, 50 mg every 12 h for 11 days, starting 24 h after the last cenerimod dose), to investigate the potential EHC of cenerimod and assess whether elimination of cenerimod can be accelerated. The multiple-dose pharmacokinetics, pharmacodynamics, safety, and tolerability of cenerimod were also evaluated. For both doses, peak plasma concentrations were reached 6 and 7 h after dosing. Cenerimod accumulated approximately eightfold and (near) steady-state conditions were reached after 50 doses, resembling clinically meaningful exposure to cenerimod. The t½ following 0.5 and 4 mg of cenerimod was 767 and 799 h (ie, 32 and 33 days) and 720 and 780 h (ie, 30 and 33 days) with or without administration of charcoal, respectively, indicating no statistically significant difference. Therefore, charcoal did not accelerate cenerimod elimination suggesting that there is no EHC of cenerimod. A reversible, dose-dependent decrease in total lymphocyte count was observed. No safety concerns were identified; administration of charcoal was well tolerated.

Association of autoantibodies with the IFN signature and NETosis in patients with systemic lupus erythematosus

Objective

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a variety of disease symptoms and an unpredictable clinical course. To improve treatment outcome, stratification based on immunological manifestations commonly seen in patients with SLE such as autoantibodies, type I interferon (IFN) signature and neutrophil extracellular trap (NET) release may help. It is assumed that there is an association between these immunological phenomena, since NET release induces IFN production and IFN induces autoantibody formation via B-cell activation. Here we studied the association between autoantibodies, the IFN signature, NET release, and clinical manifestations in patients with SLE.

Methods

We performed principal component analysis (PCA) and hierarchical clustering of 57 SLE-related autoantibodies in 25 patients with SLE. We correlated each autoantibody to the IFN signature and NET inducing capacity.

Results

We observed two distinct clusters: one cluster contained mostly patients with a high IFN signature. Patients in this cluster often present with cutaneous lupus, and have higher anti-dsDNA concentrations. Another cluster contained a mix of patients with a high and low IFN signature. Patients with high and low NET inducing capacity were equally distributed between the clusters. Variance between the clusters is mainly driven by antibodies against histones, RibP2, RibP0, EphB2, RibP1, PCNA, dsDNA, and nucleosome. In addition, we found a trend towards increased concentrations of autoantibodies against EphB2, RibP1, and RNP70 in patients with an IFN signature. We found a negative correlation of NET inducing capacity with anti-FcER (r = -0.530; p = 0.007) and anti-PmScl100 (r = -0.445; p = 0.03).

Conclusion

We identified a subgroup of patients with an IFN signature that express increased concentrations of antibodies against DNA and RNA-binding proteins, which can be useful for further patient stratification and a more targeted therapy. We did not find positive associations between autoantibodies and NET inducing capacity. Our study further strengthens the evidence of a correlation between RNA-binding autoantibodies and the IFN signature.

Double-filtration plasmapheresis reduces type I interferon bioavailability and inducing activity in systemic lupus erythematosus

Type I interferons (IFN-Is) play a significant role in systemic lupus erythematosus (SLE) pathogenesis. Double-filtration plasmapheresis (DFPP) is a treatment option for SLE; however, its effect on IFN-Is remains unclear. Therefore, we investigated the effects of DFPP on IFN-Is. Plasma from patients with SLE (n = 11) who regularly underwent DFPP was analysed using a cell-based reporter system to detect the bioavailability and inducing activity of IFN-I. The concentration of plasma dsDNA was measured, and western blotting analysis was used to assess the phosphorylation of the STING pathway. A higher IFN-I bioavailability and inducing activity were observed in patients compared to healthy controls, and both parameters decreased after DFPP. The reduction in IFN-I-inducing activity was particularly prominent in patients with high disease activity. Notably, this reduction was not observed in STING-knockout reporter cells. Additionally, plasma dsDNA levels decreased after DFPP treatment, suggesting that inhibition of the STING pathway was responsible for the observed decrease in activity. Western blotting analysis revealed suppression of STING pathway phosphorylation after DFPP. DFPP reduced IFN-I bioavailability and the inducing activity of plasma. This reduction is likely attributable to the inhibition of the STING pathway through the elimination of dsDNA.

Brain-immune interactions: implication for cognitive impairments in Alzheimer's disease and autoimmune disorders

Progressive memory loss and cognitive dysfunction, encompassing deficits in learning, memory, problem solving, spatial reasoning, and verbal expression, are characteristics of Alzheimer's disease and related dementia. A wealth of studies has described multiple roles of the immune system in the development or exacerbation of dementia. Individuals with autoimmune disorders can also develop cognitive dysfunction, a phenomenon termed "autoimmune dementia." Together, these findings underscore the pivotal role of the neuroimmune axis in both Alzheimer's disease and related dementia and autoimmune dementia. The dynamic interplay between adaptive and innate immunity, both in and outside the brain, significantly affects the etiology and progression of these conditions. Multidisciplinary research shows that cognitive dysfunction arises from a bidirectional relationship between the nervous and immune systems, though the specific mechanisms that drive cognitive impairments are not fully understood. Intriguingly, this reciprocal regulation occurs at multiple levels, where neuronal signals can modulate immune responses, and immune system-related processes can influence neuronal viability and function. In this review, we consider the implications of autoimmune responses in various autoimmune disorders and Alzheimer's disease and explore their effects on brain function. We also discuss the diverse cellular and molecular crosstalk between the brain and the immune system, as they may shed light on potential triggers of peripheral inflammation, their effect on the integrity of the blood-brain barrier, and brain function. Additionally, we assess challenges and possibilities associated with developing immune-based therapies for the treatment of cognitive decline.

Chimeric antigen receptor T-cell therapy in autoimmune diseases

The administration of T cells that have been modified to carry chimeric antigen receptors (CARs) aimed at B cells has been an effective strategy in treating B cell malignancies. This breakthrough has spurred the creation of CAR T cells intended to specifically reduce or alter the faulty immune responses associated with autoimmune disorders. Early positive outcomes from clinical trials involving CAR T cells that target the B cell protein CD19 in patients suffering from autoimmune diseases driven by B cells have been reported. Additional strategies are being developed to broaden the use of CAR T cell therapy and enhance its safety in autoimmune conditions. These include employing chimeric autoantireceptors (CAAR) to specifically eliminate B cells that are reactive to autoantigens, and using regulatory T cells (Tregs) engineered to carry antigen-specific CARs for precise immune modulation. This discussion emphasizes key factors such as choosing the right target cell groups, designing CAR constructs, defining tolerable side effects, and achieving a lasting immune modification, all of which are critical for safely integrating CAR T cell therapy in treating autoimmune diseases.

Differential lncRNA profiles of blood plasma-derived exosomes from systemic lupus erythematosus

INTRODUCTION

Long non-coding RNAs (lncRNAs) dysregulation is key in the pathogenesis of systemic lupus erythematosus (SLE), but the role of exosomal lncRNAs in SLE has not been well studied. We elucidated the profiles of plasma exosomal lncRNAs expression in patients with SLE and predictd their potential clinical significance in SLE.

METHODS

In the screening stage, six newly diagnosed and untreated patients with SLE and six healthy controls were examined by high-throughput sequencing technology, and differential exosomal lncRNA profiles were constructed. In the validation phase, two differentially selected exosomal lncRNAs from 20 patients each with active and stable SLE and 20 healthy controls were verified with RT-qPCR. The correlation between the selected exosomal lncRNAs and SLE clinical indicators was examined. The diagnostic value of the selected exosomal lncRNAs in SLE was analyzed by the receiver operator characteristic (ROC) curve.

RESULTS

Exosomes were successfully extracted from the patients and controls. Sequencing-phase sequencing demonstrated 528 upregulated lncRNAs and 7491 downregulated lncRNAs. In the validation stage, exosomal LINC00667 and DANCR were significantly upregulated in the patients, and positively correlated with Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K). Exosomal DANCR expression between the active and stable SLE patients was different. The area under the curve(AUC) of exosomal LINC00667 and DANCR for SLE diagnosis was 0.815 and 0.759, respectively.

CONCLUSIONS

Exosomal LINC00667 and DANCR were upregulated in SLE, and might be new biomarkers thereof. Exosomal DANCR was associated with SLE activity.