MiR-574-5p activates human TLR8 to promote autoimmune signaling and lupus.

Endosomal single-stranded RNA-sensing Toll-like receptor-7/8 (TLR7/8) plays a pivotal role in inflammation and immune responses and autoimmune diseases. However, the mechanisms underlying the initiation of the TLR7/8-mediated autoimmune signaling remain to be fully elucidated. Here, we demonstrate that miR-574-5p is aberrantly upregulated in tissues of lupus prone mice and in the plasma of lupus patients, with its expression levels correlating with the disease activity. miR-574-5p binds to and activates human hTLR8 or its murine ortholog mTlr7 to elicit a series of MyD88-dependent immune and inflammatory responses. These responses include the overproduction of cytokines and interferons, the activation of STAT1 signaling and B lymphocytes, and the production of autoantigens. In a transgenic mouse model, the induction of miR-574-5p overexpression is associated with increased secretion of antinuclear and anti-dsDNA antibodies, increased IgG and C3 deposit in the kidney, elevated expression of inflammatory genes in the spleen. In lupus-prone mice, lentivirus-mediated silencing of miR-574-5p significantly ameliorates major symptoms associated with lupus and lupus nephritis. Collectively, these results suggest that the miR-574-5p-hTLR8/mTlr7 signaling is an important axis of immune and inflammatory responses, contributing significantly to the development of lupus and lupus nephritis.

Analysis of m6A-regulated genes and subtype classification in lupus nephritis.

BACKGROUND: Lupus nephritis (LN) is the most common and severe clinical manifestation of systemic lupus erythematosus (SLE). N6-methyladenosine (m6A) is a reversible RNA modification and has been implicated in various biological processes. However, the roles of m6A regulators in LN are not fully demonstrated. METHODS: We downloaded the kidney tissue transcriptome dataset of LN patients and normal controls from the GEO database and extracted the expression levels of m6A regulators. We constructed and compared Random Forest (RF) and Support Vector Machine (SVM) models, and subsequently selected featured genes to develop nomogram models. The m6A subtypes were identified based on significantly differentially expressed m6A regulators, and the m6A gene subtypes were identified based on m6A-associated differential genes, and the two m6A modification patterns were comprehensively evaluated. RESULTS: We obtained the GSE32591 and GSE112943 datasets from the GEO database, including 78 LN samples and 36 normal control samples. We extracted the expression levels of 20 m6A regulators. By RF analysis we identified 7 characteristic m6A regulators and constructed nomogramh models with these 7 genes. We identified two m6A subtypes based on these seven important m6A regulators, and the immune cell infiltration levels of the two subtype clusters were significantly different. We identified two more m6A gene subtypes based on m6A-associated DEGs. We calculated the m6A scores using the principal component analysis (PCA) algorithm and found that the m6A scores of m6A cluster A and gene cluster A were lower than those of m6A cluster B and gene cluster B. In addition, we found that the levels of inflammatory factors were also significantly different between m6A clusters and gene clusters. CONCLUSION: This study confirms that m6A regulators are involved in the LN process through different modes of action and provide new diagnostic and therapeutic targets for LN.

[Analysis and precise intervention on pathogenic genes and mechanisms of lupus nephritis].

Lupus nephritis is the most common complication of systemic lupus erythematosus (SLE) and an important cause of end-stage kidney disease and death in patients with SLE. The pathogenesis of SLE is complex, with no effective treatment and poor long-term prognosis. The development of genomic medicine provides a new way to explore the disease-causing genes and pathogenesis of lupus nephritis. Here, the article introduces how to uncover the pathogenesis of lupus nephritis from the genome level and explore new strategies for diagnosis and treatment on this disease.

Integrative analysis of single-cell and bulk transcriptome data reveal the significant role of macrophages in lupus nephritis.

OBJECTIVE: We attempted to identify abnormal immune cell components and signaling pathways in lupus nephritis (LN) and to identify potential therapeutic targets. METHODS: Differentially expressed genes (DEGs) between LN and normal kidney tissues were identified from bulk transcriptome data, and functional annotation was performed. The phenotypic changes in macrophages and aberrant intercellular signaling communications within immune cells were imputed from LN scRNA-seq data using trajectory analysis and verified using immunofluorescence staining. Finally, lentivirus-mediated overexpression of LGALS9, the gene encoding Galectin 9, in THP-1 cells was used to study the functional effect of this gene on monocytic cells. RESULTS: From bulk transcriptome data, a significant activation of interferon (IFN) signaling was observed, and its intensity showed a significantly positive correlation with the abundance of infiltrating macrophages in LN. Analysis of scRNA-seq data revealed 17 immune cell clusters, with macrophages showing the highest enrichment of intercellular signal communication in LN. Trajectory analysis revealed macrophages in LN undergo a phenotypic change from inflammatory patrolling macrophages to phagocytic and then to antigen-presenting macrophages, and secrete various pro-inflammatory factors and complement components. LGALS9 was found significantly upregulated in macrophages in LN, which was confirmed by the immunofluorescence assay. Gene functional study showed that LGALS9 overexpression in THP-1 cells significantly elicited pro-inflammatory activation, releasing multiple immune cell chemoattractants. CONCLUSION: Our results present an important pathophysiological role for macrophages in LN, and our preliminary results demonstrate significant pro-inflammatory effects of LGALS9 gene in LN macrophages.

Polygenic Risk Score Predicts Earlier-Onset Adult Systemic Lupus Erythematosus and First-Year Renal Diseases in a Taiwanese Cohort.

OBJECTIVES: This study aimed to develop a predictive model using polygenic risk score (PRS) to forecast renal outcomes for adult systemic lupus erythematosus (SLE) in a Taiwanese population. METHODS: Patients with SLE (n=2782) and matched non-SLE controls (n=11 128) were genotyped using Genome-Wide TWB 2.0 single-nucleotide polymorphism (SNP) array. PRS models (C+T, LDpred2, Lassosum, PRSice-2, PRS-continuous shrinkage (CS)) were constructed for predicting SLE susceptibility. Logistic regression was assessed for C+T-based PRS association with renal involvement in patients with SLE. RESULTS: In the training set, C+T-based SLE-PRS, only incorporating 27 SNPs, outperformed other models with area under the curve (AUC) values of 0.629, surpassing Lassosum (AUC=0.621), PRSice-2 (AUC=0.615), LDpred2 (AUC=0.609) and PRS-CS (AUC=0.602). Additionally, C+T-based SLE-PRS demonstrated consistent predictive capacity in the testing set (AUC=0.620). Individuals in the highest quartile exhibited earlier SLE onset (39.06 vs 44.22 years, p<0.01), higher Systemic Lupus Erythematosus Disease Activity Index scores (3.00 vs 2.37, p=0.04), elevated risks of renal involvement within the first year of SLE diagnosis, including WHO class III-IV lupus nephritis (OR 2.36, 95% CI 1.47 to 3.80, p<0.01), estimated glomerular filtration rate <60 mL/min/1.73m2 (OR 1.49, 95% CI 1.18 to 1.89, p<0.01) and urine protein-to-creatinine ratio >150 mg/day (OR 2.07, 95% CI 1.49 to 2.89, p<0.01), along with increased seropositivity risks, compared with those in the lowest quartile. Furthermore, among patients with SLE with onset before 50 years, the highest PRS quartile was significantly associated with more serious renal diseases within the first year of SLE diagnosis. CONCLUSIONS: PRS of SLE is associated with earlier onset, renal involvement within the first year of SLE diagnosis and seropositivity in Taiwanese patients. Integrating PRS with clinical decision-making may enhance lupus nephritis screening and early treatment to improve renal outcomes in patients with SLE.

Machine learning-based identification of novel hub genes associated with oxidative stress in lupus nephritis: implications for diagnosis and therapeutic targets.

BACKGROUND: Lupus nephritis (LN) is a complication of SLE characterised by immune dysfunction and oxidative stress (OS). Limited options exist for LN. We aimed to identify LN-related OS, highlighting the need for non-invasive diagnostic and therapeutic approaches. METHODS: LN-differentially expressed genes (DEGs) were extracted from Gene Expression Omnibus datasets (GSE32591, GSE112943 and GSE104948) and Molecular Signatures Database for OS-associated DEGs (OSEGs). Functional enrichment analysis was performed for OSEGs related to LN. Weighted gene co-expression network analysis identified hub genes related to OS-LN. These hub OSEGs were refined as biomarker candidates via least absolute shrinkage and selection operator. The predictive value was validated using receiver operating characteristic (ROC) curves and nomogram for LN prognosis. We evaluated LN immune cell infiltration using single-sample gene set enrichment analysis and CIBERSORT. Additionally, gene set enrichment analysis explored the functional enrichment of hub OSEGs in LN. RESULTS: The study identified four hub genes, namely STAT1, PRODH, TXN2 and SETX, associated with OS related to LN. These genes were validated for their diagnostic potential, and their involvement in LN pathogenesis was elucidated through ROC and nomogram. Additionally, alterations in immune cell composition in LN correlated with hub OSEG expression were observed. Immunohistochemical analysis reveals that the hub gene is most correlated with activated B cells and CD8 T cells. Finally, we uncovered that the enriched pathways of OSEGs were mainly involved in the PI3K-Akt pathway and the Janus kinase-signal transducer and activator of transcription pathway. CONCLUSION: These findings contribute to advancing our understanding of the complex interplay between OS, immune dysregulation and molecular pathways in LN, laying a foundation for the identification of potential diagnostic biomarkers and therapeutic targets.

Uncovering lupus nephritis-specific genes and the potential of TNFRSF17-targeted immunotherapy: a high-throughput sequencing study.

Introduction: Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE). This study aimed to identify LN specific-genes and potential therapeutic targets. Methods: We performed high-throughput transcriptome sequencing on peripheral blood mononuclear cells (PBMCs) from LN patients. Healthy individuals and SLE patients without LN were used as controls. To validate the sequencing results, qRT-PCR was performed for 5 upregulated and 5 downregulated genes. Furthermore, the effect of the TNFRSF17-targeting drug IBI379 on patient plasma cells and B cells was evaluated by flow cytometry. Results: Our analysis identified 1493 and 205 differential genes in the LN group compared to the control and SLE without LN groups respectively, with 70 genes common to both sets, marking them as LN-specific. These LN-specific genes were significantly enriched in the 'regulation of biological quality' GO term and the cell cycle pathway. Notably, several genes including TNFRSF17 were significantly overexpressed in the kidneys of both LN patients and NZB/W mice. TNFRSF17 levels correlated positively with urinary protein levels, and negatively with complement C3 and C4 levels in LN patients. The TNFRSF17-targeting drug IBI379 effectively induced apoptosis in patient plasma cells without significantly affecting B cells. Discussion: Our findings suggest that TNFRSF17 could serve as a potential therapeutic target for LN. Moreover, IBI379 is presented as a promising treatment option for LN.

Clinical significance of miR-200a in systemic lupus erythematosus and renal damage in children.

The purpose was to analyze the clinical significance of miR-200a in children with initially diagnosed SLE and renal damage. Children with initially diagnosed SLE (n=100) and healthy children (n=50) undergoing physical examinations during the same period were recruited. Disease activity of SLE children was determined based on SLEDAI (systemic lupus erythematosus disease activity index), and they were divided to SLEDAI≤9 group and SLEDAI>9 group, respectively. Moreover, SLE children were divided to LN group and non-LN group based on the occurrence of lupus nephritis. Differential level of miR-200a between groups was detected by qRT-PCR. Spearman correlation test was conducted to analyze the influence of miR-200a on SLEDAI and other laboratory indexes of SLE children. Its diagnostic potential in SLE and LN was assessed through depicting ROC curves. MiR-200a level was remarkably lower in SLE children than that of healthy children. Lower level of miR-200a was detected in SLE children with high SLEDAI or accompanied LN. MiR-200a level was negatively correlated to SLEDAI (r=-0.425), ESR (r=-0.284), CRP (r=-0.338), BUN (r=-0.263) and Scr (r=-0.345), while it was positively correlated to C3 (r=0.631), C4 (r=0.524) and ALB (r=0.394) in SLE children. The AUC of miR-200a in diagnosing SLE was 0.8379 (cut-off value=2.225, sensitivity=70%, specificity=70%). Besides, the AUC of miR-200a in diagnosing LN was 0.7619 (cut-off value=2.005, sensitivity=80%, specificity=76%). MiR-200a level has a certain correlation to the disease activity of children with initially diagnosed SLE, which can be utilized as an adjuvant indicator in evaluating SLE severity. Meanwhile, miR-200a has predictive value for SLE-induced renal damage.

Identification of new hub- ferroptosis-related genes in Lupus Nephritis.

Background: Lupus Nephritis (LN) is the primary causation of kidney injury in systemic lupus erythematosus (SLE). Ferroptosis is a programmed cell death. Therefore, understanding the crosstalk between LN and ferroptosis is still a significant challenge. Methods: We obtained the expression profile of LN kidney biopsy samples from the Gene Expression Omnibus database and utilised the R-project software to identify differentially expressed genes (DEGs). Then, we conducted a functional correlation analysis. Ferroptosis-related genes (FRGs) and differentially expressed genes (DEGs) crossover to select FRGs with LN. Afterwards, we used CIBERSORT to assess the infiltration of immune cells in both LN tissues and healthy control samples. Finally, we performed immunohistochemistry on LN human renal tissue. Results: 10619 DEGs screened from the LN biopsy tissue were identified. 22 hub-ferroptosis-related genes with LN (FRGs-LN) were screened out. The CIBERSORT findings revealed that there were significant statistical differences in immune cells between healthy control samples and LN tissues. Immunohistochemistry further demonstrated a significant difference in HRAS, TFRC, ATM, and SRC expression in renal tissue between normal and control groups. Conclusion: We developed a signature that allowed us to identify 22 new biomarkers associated with FRGs-LN. These findings suggest new insights into the pathology and therapeutic potential of LN ferroptosis inhibitors and iron chelators.

Expression profile of long-noncoding RNAs MIR31HG, NKILA, and PACER in systemic lupus erythematosus patients.

OBJECTIVES: Growing evidence suggests that systemic lupus erythematosus (SLE), an organ-damaging systemic autoimmune illness, may be influenced by long-noncoding RNAs (lncRNAs). This study aimed to assess the relative expression of lncRNAs (MIR31HG, NKILA, and PACER) in patients with SLE to evaluate their role in the disease. DESIGN AND METHODS: This study involved 70 patients with SLE and 70 apparently healthy control subjects. The expression levels of lnc-MIR31HG, NKILA, and PACER were quantified using real-time PCR. RESULTS: Lnc-MIR31HG, NKILA, and PACER were significantly upregulated in SLE cases compared to controls (P < 0.001). ROC curve analysis revealed a 91.43 % sensitivity of PACER for the diagnosis of SLE at a cutoff point of > 1.46, followed by NKILA with 90 % sensitivity at a cutoff point of > 1.16, and MIR31HG with 85.71 % sensitivity at a cutoff point of > 1.43. MIR31HG had the highest sensitivity for the diagnosis of lupus nephritis (86.67 %) at a cutoff point of > 7.19, then NKILA with 80 % sensitivity at a cutoff point of > 8.12, and finally PACER expression with 73.33 % sensitivity at a cutoff point of > 18.19. Moreover, MIR31HG and NKILA revealed a significant correlation with albumin/creatinine ratio, estimated glomerular filtration rate, and the SLEDAI score. Regression analysis revealed the potential roles of MIR31HG, NKILA, and PACER expression as predictors for SLE. CONCLUSION: An upregulated lncRNA panel (MIR31HG, NKILA, and PACER) could play a role in the pathogenesis and, hence, the predispositiontoSLE. MIR31HG and NKILA can serve as prognostic markers significantly linked with disease activity.

Effect of M0 macrophage-derived exosome miR-181d-5p targeting BCL-2 to regulate NLRP3/caspase-1/GSDMD pathway on human renal mesangial cells pyroptosis.

BACKGROUND: Lupus nephritis (LN) is a type of autoimmune disease that impacts the kidneys. Exosomes are valuable for in-depth studies of the pathogenesis of LN. This study aimed to explore miR-181d-5p expression levels in M0 macrophage-derived exosomes and their role in human renal mesangial cells (HRMC) pyroptosis through binding to BCL-2. METHODS: Peripheral blood mononuclear cells (PBMCs) were collected from patients with lupus nephritis (LN) and healthy subjects. Monocytes isolated from these samples were induced into M0 macrophages using recombinant human granulocyte colony-stimulating factor (rhG-CSF). In a parallel process, THP-1 cells were induced into M0 macrophages using Phorbol Myristate Acetate (PMA). LPS- and ATP-stimulated HRMC were used to construct a cell pyroptosis model. We then introduced different miR-181d-5p mimic fragments into the M0 macrophages derived from the THP-1 cells. Subsequently, exosomes from these macrophages were co-cultured with HRMC. To evaluate the impact on HRMC, we conducted proliferation and apoptosis assessments using CellCountingKit-8assay and flow cytometry. The effect of exosomal miR-181d-5p on HRMC pyroptosis was assessed using western blot. The miR-181d-5p and BCL-2 targeting relationship was detected using real-time fluorescence quantitative PCR. IL-6, IL-1ß, and TNF-α levels in cell supernatants were detected using ELISA kits. RESULTS: In this study, we observed an increase in miR-181d-5p levels within exosomes secreted from M0 macrophages obtained by induction of monocytes from LN patients. It was found that miR-181d-5p can target binding to BCL-2. Exosomes with elevated levels of miR-181d-5p contributed to a significant increase in miR-181d-5p within HRMC, facilitating its proliferation and inhibiting apoptosis. Furthermore, exosomes expressing high levels of miR-181d-5p were observed to promote an inflammatory response and pyroptosis in HRMC. Notably, these effects were reversed when the levels of miR-181d-5p in the exosomes were reduced. CONCLUSION: Inhibition of miR-181d-5p, derived from M0 macrophage exosomes, effectively suppresses inflammation and pyroptosis in HRMC. This discovery indicates that miR-181d-5p holds the potential as a valuable target in the development of treatments for Lupus Nephritis (LN).

Potential involvement of circulating exosomal miRNA-146a in disease activity and TRAF6 gene expression in juvenile proliferative lupus nephritis.

BACKGROUND: Juvenile SLE (JSLE) is a complex autoimmune disorder that predominantly affects children and adolescents with several unique challenges, and microRNA-146a (miRNA-146a) might be an interesting anti-inflammatory molecule. Because exosomes in the blood might protect miRNAs, the association between circulating exosomal miRNA-146a and lupus proinflammatory genes, such as IRAK1 and TRAF6, was studied in peripheral blood mononuclear cells from people with JSLE. METHODS: Blood samples from 12 patients were collected every 3 months until 1 year with the recorded disease activity, and quantitative real-time PCR was used to determine the circulating exosomal miRNA-146a and the gene expression (IRAK1 and TRAF6). RESULTS: The mean age was 12.60±0.43 years at diagnosis and all patients had a complete response at 12 months. According to the nanoparticle tracking analysis, the abundance of exosomes was significantly lower at 3, 6 and 12 months compared with 0 months, while the level of circulating exosomal miRNA-146a was significantly higher at 12 months than at diagnosis (p<0.001). There was a negative correlation between the level of circulating exosomal miRNA-146a expression and the level of TRAF6 mRNA (r=-0.30, p=0.049). Moreover, there were correlations between circulating exosomal miRNA-146a and disease severity such as SLE Disease Activity Index 2000 score, anti-double-stranded DNA antibody and proteinuria (urine protein-creatinine ratio), respectively. Therefore, increasing the level of circulating exosomal miRNA-146a, which might control TRAF6 mRNA expression, could have an effect on the production of inflammatory cytokines. CONCLUSION: This suggests that miRNA-146a might serve as a non-invasive biomarker to evaluate the response to treatment in patients with juvenile lupus nephritis.

Proximity extension assay proteomics and renal single cell transcriptomics uncover novel urinary biomarkers for active lupus nephritis.

OBJECTIVE: To identify urinary biomarkers that can distinguish active renal involvement in Lupus Nephritis (LN), a severe manifestation of systemic lupus erythematosus (SLE). METHODS: Urine from 117 subjects, comprised of inactive SLE, active non-renal lupus, active LN, and healthy controls, were subjected to Proximity Extension Assay (PEA) based comprehensive proteomics followed by ELISA validation in an independent, ethnically diverse cohort. Proteomic data is also cross-referenced to renal transcriptomic data to elucidate cellular origins of biomarkers. RESULTS: Systems biology analyses revealed progressive activation of cytokine signaling, chemokine activity and coagulation pathways, with worsening renal disease. In addition to validating 30 previously reported biomarkers, this study uncovers several novel candidates. Following ELISA validation in an independent cohort of different ethnicity, the six most discriminatory biomarkers for active LN were urinary ICAM-2, FABP4, FASLG, IGFBP-2, SELE and TNFSF13B/BAFF, with ROC AUC ≥80%, with most correlating strongly with clinical disease activity. Transcriptomic analyses of LN kidneys mapped the likely origin of these proteins to intra-renal myeloid cells (CXCL16, IL-1RT2, TNFSF13B/BAFF), T/NK cells (FASLG), leukocytes (ICAM2) and endothelial cells (SELE). CONCLUSION: In addition to confirming the diagnostic potential of urine ALCAM, CD163, MCP1, SELL, ICAM1, VCAM1, NGAL and TWEAK for active LN, this study adds urine ICAM-2, FABP4, FASLG, IGFBP-2, SELE, and TNFSF13B/BAFF as additional markers that warrant systematic validation in larger cross-sectional and longitudinal cohorts.

Inhibition of STAT3 alleviates LPS-induced apoptosis and inflammation in renal tubular epithelial cells by transcriptionally down-regulating TASL.

BACKGROUND: Systemic lupus erythematosus (SLE) is a common autoimmune disease that impacts various organs. Lupus nephritis (LN) significantly contributes to death in children with SLE. Toll-like receptor (TLR) adaptor interacting with SLC15A4 on the lysosome (TASL) acts as an innate immune adaptor for TLR and is implicated in the pathogenesis of SLE. A transcription factor known as signal transducer and activator of transcription 3 (STAT3), which is known to be linked to autoimmune diseases, is also involved in the development of SLE. METHODS: Bioinformatics and real-time quantitative PCR (qRT-PCR) was used to detect the expression of STAT3 and TASL in peripheral blood of SLE patients and their correlation. Bioinformatics analysis, qRT-PCR, luciferase assay and chromatin immunoprecipitation (ChIP) were used to verify the regulation of transcription factor STAT3 on TASL. The expression levels of STAT3, TASL and apoptosis-related genes in LPS-induced HK2 cells were detected by qRT-PCR and Western blot. TUNEL staining were used to detect the apoptosis of HK2 cells after LPS stimulation. ELISA and qRT-PCR were used to detect the levels of inflammatory cytokines in the cell culture supernatant. TASL knockdown in HK2 cells was used to detect the changes in apoptosis-related genes and inflammatory factors. The expression level of TASL in LPS-stimulated HK2 cells and its effect on cell apoptosis and inflammatory factors were observed by knocking down and overexpressing STAT3, respectively. It was also verified in a rescue experiment. RESULTS: The expressions of STAT3 and TASL were higher in SLE than in healthy children, and the expression of STAT3 was positively correlated with TASL. Transcription factor STAT3 can directly and positively regulate the expression of TASL through the promoter region binding site. The expression of STAT3, TASL and inflammatory cytokines was elevated, and the change of apoptosis was up-regulated in LPS-stimulated HK2 cells. Inhibition of STAT3 alleviates LPS-stimulated apoptosis and inflammatory response in HK2 cells through transcriptional regulation of TASL. CONCLUSIONS: These findings provide new insights into the transcriptional regulation of TASL and provide new evidence of a direct regulatory relationship between signaling nodes in the lupus signaling network.

STING upregulation mediates ferroptosis and inflammatory response in lupus nephritis by upregulating TBK1 and activating NF-κB signal pathway.

Accumulated evidence implicates lipid peroxidation as a key mechanism contributing to the pathogenesis of lupus nephritis (LN). Ferroptosis is a specialized form of cell death induced by loss or deficient activity of the glutathione peroxidase 4 (GPX4) and decreased clearance of polyunsaturated fatty acid hydroperoxides. STING production may lead to the occurrence of intracellular lipid peroxidation, ultimately triggering ferroptosis, but it has not been clarified whether STING can aggravate LN via ferroptosis. The adjacent normal kidney tissues from renal cell carcinoma and biopsied kidney tissue samples from LN patients were used for research, and the expression of STING protein in kidney tissue was detected by immunohistochemistry and RT-qPCR. MRL/lpr mice, a model of LN, were used to detect STING expression in kidney tissue. STING expression in the kidney tissue of MRL/lpr mice was knocked down by sh-STING-AAV, and then levels of 4-HNE, MDA, ROS, iron ion, blood urea nitrogen and serum creatinine, IL-6, IL-1ß, and TNF-α, and the protein expression of STING, TBK1, NF-κB, GPX4, ACSL4, and SLC7A11 were subsequently examined. STING was elevated in the kidney tissue of LN patients and MRL/lpr mice. Compared with the MRL/lpr group, liproxstatin-1 or ferrostatin-1 treatment alleviated ferroptosis-related indicators 4-HNE, MDA, ROS, iron ion release, and GPX4 and SLC7A1 expression, whereas the treatment enhanced ACSL4 expression. STING interference observably decreased 4-HNE, ROS, MDA, iron ion, STING, and ACSL4 levels, and increased GPX4 and SLC7A11 expression in MRL/lpr mice kidney tissues. Besides, inhibition of STING reduced kidney tissue damage and inflammatory cell infiltration in MRL/lpr mice, and levels of serum creatinine, blood urea nitrogen, serum anti-double-stranded DNA antibody, inflammatory factors IL-6, IL-1ß, and TNF-α, as well as phosphorylation of NF-κB were all significantly decreased in MRL/lpr mice. TBK1 over expression reversed the impact of STING inhibition on ferroptosis and inflammatory response. STING contributed to ferroptosis and inflammatory response by activating the TBK1/NF-κB pathway, suggesting that STING may be a potent therapeutic target in LN.

Association of the rs1126616 and rs9138 Variants in the SPP1 Gene among Mexican Patients with Systemic Lupus Erythematosus and Lupus Nephritis.

Systemic lupus erythematosus (SLE) is a multisystem disease considered a prototype of the main autoimmune disease and presents serious complications, such as lupus nephritis (LN), which generates a significant impact on morbidity and mortality. The SPP1 gene encodes the osteopontin (OPN) protein, which plays a crucial role in the regulation of inflammation and immunity. The variants rs1126616 and rs9138 of this gene have been associated with the inflammatory response. The study aims to analyze the association of the rs1126616 and rs9138 variants of the SPP1 gene in SLE Mexican-Mestizo patients without LN (SLE-LN). In this cross-sectional study, a total of 171 genomic DNA samples from SLE patients were clinically confirmed, of which 111 were SLE without LN, 60 were SLE with LN, and 100 healthy individuals were included as reference group. The rs1126616 variant was genotyped using PCR-RFLPs, and the rs9138 variant was genotyped using qPCR TaqMan. The TT genotype, the recessive model [OR 2.76 (95% CI 1.31-5.82), p = 0.011], and the T allele [OR 2.0 (95% CI 1.26-3.16), p = 0.003] of the rs1126616 variant are risk factors for SLE with LN. By contrast, the rs9138 variant did not show statistically significant differences among SLE patients stratified by LN. In our study of SLE Mexican-Mestizo patients with and without NL, demographic and clinical characteristics do not differ from other SLE populations, and the TT genotype of the rs1126616 variant of the SPP1 gene confers a risk factor for the presentation of LN. Otherwise, the rs9138 variant did not show association with NL.

Transcription Factors in the Pathogenesis of Lupus Nephritis and Their Targeted Therapy.

Systemic lupus erythematosus (SLE) is a prototype inflammatory autoimmune disease, characterized by breakdown of immunotolerance to self-antigens. Renal involvement, known as lupus nephritis (LN), is one of the leading causes of morbidity and a significant contributor to mortality in SLE. Despite current pathophysiological advances, further studies are needed to fully understand complex mechanisms underlying the development and progression of LN. Transcription factors (TFs) are proteins that regulate the expression of genes and play a crucial role in the development and progression of LN. The mechanisms of TF promoting or inhibiting gene expression are complex, and studies have just begun to reveal the pathological roles of TFs in LN. Understanding TFs in the pathogenesis of LN can provide valuable insights into this disease's mechanisms and potentially lead to the development of targeted therapies for its management. This review will focus on recent findings on TFs in the pathogenesis of LN and newly developed TF-targeted therapy in renal inflammation.

Monogenic systemic lupus erythematosus onset in a 13-year-old boy with Noonan like-syndrome: a case report and literature review.

BACKGROUND: Childhood systemic lupus erythematosus (cSLE) has been considered as a polygenic autoimmune disease; however, a monogenic lupus-like phenotype is emerging with the recent recognition of several related novel high-penetrance genetic variants. RASopathies, a group of disorders caused by mutations in the RAS/MAPK pathway, have been recently described as a cause of monogenic lupus. CASE PRESENTATION: We present a 13-year-old boy with Noonan-like syndrome with loose anagen hair who developed a monogenic lupus. The renal biopsy confirmed a class III lupus nephritis and identified the presence of zebra bodies. CONCLUSIONS: RASopathies represent a cause of monogenic lupus. We report a new case of monogenic lupus in a child with Noonan-like syndrome with loose anagen hair. Lupus nephritis which has never been described in this context, may be part of the presentation. The presence of zebra bodies in SLE or RASopathies in unclear, but no other known conditions (Fabry disease or drugs) were identified as the cause of zebra bodies in our patient.

Identification of pattern recognition receptor genes in peripheral blood mononuclear cells and monocytes as biomarkers for the diagnosis of lupus nephritis.

BACKGROUND: The study aimed to investigate the diagnostic value of lupus-related pattern recognition receptors (PRRs) genes in peripheral blood mononuclear cells (PBMCs) and monocytes (MONs) for lupus nephritis (LN). METHODS: PBMCs were isolated from a cohort with 37 LN patients and 39 healthy controls (HCs), and MONs were derived from another cohort with 70 LN patients and 66 HCs. Q-PCR was used to measure the mRNA levels of CGAS, IFNB1, AIM2, IL1Β, NLRC4, NLRP3, NLRP12 and ZBP1 in the PBMCs and MONs. The Mann-Whitney U test was used to compare the data in LN patients and HCs. Eleven GEO datasets of SLE/LN were used to perform differentially expressed genes (DEGs) analysis to these PRR genes. Receiver operating characteristic (ROC) curve analysis was employed to assess the performance of individual genes or the disease prediction model established by combining multiple genes in LN diagnosis. Spearman correlation method was done to analyze the correlation between these PRRs and other clinical characteristics. RESULTS: The mRNA levels of five genes (AIM2, NLRC4, IL1B, NLRP12 and ZBP1) in PBMCs, and seven genes (CGAS, IFNB1, AIM2, IL1B, NLRP3, NLRP12 and ZBP1) in MONs of LN patients were significantly higher than those of HCs (P < 0.05). DEGs analysis based on the GEO datasets showed that ZBP1, AIM2 and IL1B were significantly increased in several datasets. The ROC curve analysis indicated that the area under curve (AUC) of the LN prediction models derived from PBMCs or MONs were 0.82 or 0.91 respectively. In addition, the expression levels of these PRRs were correlated with other clinical features in LN patients, including Anti-Sm, ESR, serum Cr, and C3. CONCLUSION: Our study suggests that these lupus-related PRRs might be served as potential biomarkers of LN.

MicroRNA miR-181d-5p regulates the MAPK signaling pathway by targeting mitogen-activated protein kinase 8 (MAPK8) to improve lupus nephritis.

BACKGROUND: Lupus nephritis (LN) is a common immune disease. The microRNA (miR)-181d-5p is a potential target for treating kidney injury. However, the therapeutic role of miR-181d-5p in LN has not been investigated. This study aimed to investigate the role of miR-181d-5p in targeting mitogen-activated protein kinase 8 (MAPK8) and stimulating the MAPK signaling pathway in LN. METHODS: RT-qPCR was performed to identify the variations in miR-181d-5p expression in peripheral blood mononuclear cells (PBMCs) obtained from 42 LN patients, 30 healthy individuals, 6 MRL/lpr mice and 6 C57BL/6 mice. Western blot was used to detect the effect of miR-181d-5p on the MAPK signaling pathway in THP-1 cells and MRL/lpr mice. Enzyme-linked immunosorbent assay (ELISA) was utilized to detect the effect of miR-181d-5p on antinuclear antibodies and inflammatory factors. A dual-luciferase reporter assay was used to verify whether miR-181d-5p directly targets MAPK8. Flow cytometry was performed to evaluate apoptosis rates in transfected THP-1 cells. RESULTS: miR-181d-5p expression was downregulated in PBMCs of LN patients (P < 0.01) and MRL/lpr mice (P < 0.05). A dual luciferase reporter assay demonstrated that miR-181d-5p inhibits MAPK8 (P < 0.01). Overexpression of miR-181d-5p inhibited the phosphorylation of p38 (P < 0.001) and p44/42 (P < 0.01). Moreover, miR-181d-5p decreased the apoptosis rate of THP-1 cells (P < 0.001), and reduced the secretion of IL-6 (P < 0.01) and TNF-α (P < 0.01). Furthermore, overexpression of miR-181d-5p decreased anti-dsDNA antibody (P < 0.05), anti-Sm antibody (P < 0.01), and fibrosis levels in MRL/lpr mice. CONCLUSION: Upregulation of miR-181d-5p showed anti-inflammatory and anti-apoptotic effects on THP-1 cells in vitro and kidney injury in vivo. These effects were achieved by miR-181d-5p targeting MAPK8 to inhibit phosphorylation of p38 and p44/42. These results may offer new insights for improving therapeutic strategies against lupus nephritis.