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Objective: Disruption of B cell homeostasis and subsequent dominance of effector B cell subsets are critical for the development of systemic lupus erythematosus (SLE). Revealing the key intrinsic regulators involved in the homeostatic control of B cells has important therapeutic value for SLE. This study was undertaken to determine the regulatory role of the transcription factor Pbx1 in B cell homeostasis and lupus pathogenesis. Methods: We constructed mice with B cell–specific deletion of Pbx1. T cell–dependent and T cell–independent humoral responses were induced by intraperitoneal injection of nitrophenyl‐containing hapten (NP) conjugated to keyhole limpet hemocyanin or NP‐Ficoll. The regulatory effects of Pbx1 on autoimmunity were observed in a Bm12‐induced lupus murine model. We investigated mechanisms of Pbx1 using RNA sequencing, the cleavage under targets and tagmentation assay, and chromatin immunoprecipitation–quantitative polymerase chain reaction assay. We transduced B cells from SLE patients with plasmids that overexpressed PBX1 to explore the in vitro therapeutic efficacy of PBX1. Results: Pbx1 was specifically down‐regulated in autoimmune B cells and negatively correlated with disease activity. The deficiency of Pbx1 in B cells resulted in excessive humoral responses following immunization. In the Bm12‐induced lupus model, mice with B cell–specific Pbx1 deficiency displayed enhancements in germinal center responses, plasma cell differentiation, and autoantibody production. Pbx1‐deficient B cells had increased survival and proliferative advantages after activation. Pbx1 regulated genetic programs by directly targeting critical components of the proliferation and apoptosis pathways. In SLE patients, PBX1 expression was negatively correlated with effector B cell expansion; when PBX1 expression was enforced, the survival and proliferative capacity of SLE B cells were attenuated. Conclusion: Our study reveals the regulatory function and mechanism of Pbx1 in adjusting B cell homeostasis and highlights Pbx1 as a therapeutic target in SLE. [ABSTRACT FROM AUTHOR]

Objective: Increased Toll‐like receptor 7 (TLR‐7) signaling leading to the production of type I interferon (IFN) is an important contributor to human systemic lupus erythematosus (SLE). Protein kinase C and casein kinase substrate in neurons 1 (PACSIN1), a molecule that regulates synaptic vesicle recycling, has been linked to TLR‐7/TLR‐9–mediated type I IFN production in humans and mice, but the underlying mechanism is unknown. We undertook this study to explore the pathogenicity and underlying mechanism of a de novo PACSIN1 missense variant identified in a child with SLE. Methods: PACSIN1 Q59K de novo and null variants were introduced into a human plasmacytoid dendritic cell line and into mice using CRISPR/Cas9 editing. The effects of the variants on TLR‐7/TLR‐9 signaling in human and mouse cells, as well as PACSIN1 messenger RNA and IFN signature in SLE patients, were assessed using real‐time polymerase chain reaction and flow cytometry. Mechanisms were investigated using luciferase reporter assays, RNA interference, coimmunoprecipitation, and immunofluorescence. Results: We established that PACSIN1 forms a trimolecular complex with tumor necrosis factor receptor–associated factor 4 (TRAF4) and TRAF6 that is important for the regulation of type I IFN. The Q59K mutation in PACSIN1 augments binding to neural Wiskott‐Aldrich syndrome protein while it decreases binding to TRAF4, leading to unrestrained TRAF6‐mediated activation of type I IFN. Intriguingly, PACSIN1 Q59K increased TLR‐7 but not TLR‐9 signaling in human cells, leading to elevated expression of IFNβ and IFN‐inducible genes. Untreated SLE patients had high PACSIN1 expression in peripheral blood cells that correlated positively with IFN‐related genes. Introduction of the Pacsin1 Q59K mutation into mice caused increased surface TLR‐7 and TRAIL expression in B cells. Conclusion: PACSIN1 Q59K increases IFNβ activity through the impairment of TRAF4‐mediated inhibition of TLR‐7 signaling, possibly contributing to SLE risk. [ABSTRACT FROM AUTHOR]

Objective: IRF5 plays a crucial role in the development of lupus. Genome‐wide association studies have identified several systemic lupus erythematosus (SLE) risk single‐nucleotide polymorphisms (SNPs) enriched in the IRF5 locus. However, no comprehensive genome editing–based functional analysis exists to establish a direct link between these variants and altered IRF5 expression, particularly for enhancer variants. This study was undertaken to dissect the regulatory function and mechanisms of SLE IRF5 enhancer risk variants and to explore the utilization of clustered regularly interspaced short palindromic repeat interference (CRISPRi) to regulate the expression of disease risk gene to intervene in the disease. Methods: Epigenomic profiles and expression quantitative trait locus analysis were applied to prioritize putative functional variants in the IRF5 locus. CRISPR‐mediated deletion, activation, and interference were performed to investigate the genetic function of rs4728142. Allele‐specific chromatin immunoprecipitation–quantitative polymerase chain reaction and allele‐specific formaldehyde‐assisted isolation of regulatory element–quantitative polymerase chain reaction were used to decipher the mechanism of alleles differentially regulating IRF5 expression. The CRISPRi approach was used to evaluate the intervention effect in monocytes from SLE patients. Results: SLE risk SNP rs4728142 was located in an enhancer region, indicating a disease‐related regulatory function, and risk allele rs4728142‐A was closely associated with increased IRF5 expression. We demonstrated that an rs4728142‐containing region could act as an enhancer to regulate the expression of IRF5. Moreover, rs4728142 affected the binding affinity of zinc finger and BTB domain–containing protein 3 (ZBTB3), a transcription factor involved in regulation. Furthermore, in monocytes from SLE patients, CRISPR‐based interference with the regulation of this enhancer attenuated the production of disease‐associated cytokines. Conclusion: These results demonstrate that the rs4728142‐A allele increases the SLE risk by affecting ZBTB3 binding, chromatin status, and regulating IRF5 expression, establishing a biologic link between genetic variation and lupus pathogenesis. [ABSTRACT FROM AUTHOR]

Objective The long non-coding RNA plays an important role in inflammation and autoimmune diseases. The aim of this study is to screen and identify abnormally expressed lncRNAs in peripheral blood neutrophils of SLE patients as novel biomarkers and to explore the relationship between lncRNAs levels and clinical features, disease activity and organ damage. Methods RNA-seq technology was used to screen differentially expressed lncRNAs in neutrophils from SLE patients and healthy donors. Based on the results of screening, candidate lncRNA levels in neutrophils of 88 SLE patients, 35 other connective disease controls, and 78 healthy controls were qualified by real-time quantitative polymerase chain reaction. Results LncRNA expression profiling revealed 360 up-regulated lncRNAs and 224 down-regulated lncRNAs in neutrophils of SLE patients when compared with healthy controls. qPCR assay validated that the expression of Lnc-FOSB-1:1 was significantly decreased in neutrophils of SLE patients when compared with other CTD patients or healthy controls. It correlated negatively with SLE Disease Activity Index 2000 (SLEDAI-2K) score (r = −0.541, P < 0.001) and IFN scores (r = −0.337, P = 0.001). More importantly, decreased Lnc-FOSB-1:1 expression was associated with lupus nephritis. Lower baseline Lnc-FOSB-1:1 level was associated with higher risk of future renal involvement (within an average of 2.6 years) in patients without renal disease at baseline (P = 0.019). Conclusion LncRNA expression profile in neutrophils of SLE patients revealed differentially expressed lncRNAs. Validation study on Lnc-FOSB-1:1 suggest that it is a potential biomarker for prediction of near future renal involvement. [ABSTRACT FROM AUTHOR]

Objective Systemic juvenile idiopathic arthritis (JIA) is an inflammatory disease of childhood in which cells of the monomyelocytoid lineage are thought to be key effector cells. Monocytes from patients with systemic JIA have a distinct phenotype, with features of both M1 and M2 alternative activation. MicroRNAs are critical regulators of monocyte polarization and function, but cellular microRNAs in systemic JIA have not been examined systematically. Methods MicroRNA TaqMan arrays were used to determine the expression profiles of monocytes from children with systemic JIA. Expression of microRNA-125a-5p (miR-125a-5p) and its contribution to monocyte polarization were examined using in vitro-polarized THP-1 cells and primary human monocytes. Results A total of 110 microRNAs were found to be differentially expressed in monocytes from patients with active systemic JIA, including molecules implicated in rheumatoid arthritis pathogenesis, cytokine production, and monocyte polarization. MicroRNA-125a-5p was identified as being highly up-regulated in monocytes from children with active systemic JIA, as compared to those from children with clinically inactive JIA or those with active polyarticular JIA, and correlated with systemic features of the disease. In vitro, monocyte miR125a-5p expression was increased after polarization under M2b or M2c conditions. Inhibition of miR-125a-5p showed that this microRNA contributed to full polarization of M2b regulatory macrophages. In contrast, miR-125a-5p overexpression enhanced M2b polarization and altered other polarized populations, including increasing the production of M2 markers. Indeed, in vitro overexpression of this microRNA altered the macrophage phenotype toward that observed in systemic JIA. Conclusion Children with active systemic JIA have profound alterations in the expression of microRNAs that are implicated in monocyte function and polarization. One of these microRNAs, miR-125a-5p, is also a regulator of immunoregulatory M2b macrophages. [ABSTRACT FROM AUTHOR]

Objective Type I interferon (IFN) is a critical pathogenic factor during the progression of lupus nephritis (LN). Although microRNAs (miRNAs) have been shown to control the IFN response in immune cells in LN, the role of miRNAs in resident renal cells remains unclear. We undertook this study to investigate the role of microRNA-130b (miR-130b) in the IFN pathway in renal cells as well as its therapeutic effect in LN. Methods Kidney tissues from patients and (NZB × NZW)F1 lupus-prone mice were collected for detecting miR-130b levels. Primary renal mesangial cells (RMCs) were used to determine the role of miR-130b in the IFN pathway. We overexpressed miR-130b by administering miR-130b agomir in a mouse model of IFNα-accelerated LN to test its therapeutic efficacy. Results Down-regulated miR-130b expression was observed in kidney tissues from patients and lupus-prone mice. Further analysis showed that underexpression of miR-130b correlated negatively with abnormal activation of the IFN response in LN patients. In vitro, overexpressing miR-130b suppressed signaling downstream from the type I IFN pathway in RMCs by targeting IFN regulatory factor 1 (IRF-1). The opposite effect was observed when endogenous miR-130b expression was inhibited. The inverse correlation between IRF1 and miR-130b levels was detected in renal biopsy samples from LN patients. More importantly, in vivo administration of miR-130b agomir reduced IFNα-accelerated progression of LN, with decreased proteinuria, lower levels of immune complex deposition, and lack of glomerular lesions. Conclusion MicroRNA-130b is a novel negative regulator of the type I IFN pathway in renal cells. Overexpression of miR-130b in vivo ameliorates IFNα-accelerated LN, providing potential novel strategies for therapeutic intervention in LN. [ABSTRACT FROM AUTHOR]

Objective Type I interferon (IFN) signaling is regarded as a central pathogenic pathway in systemic lupus erythematosus (SLE). Specific inhibition of this pathway is a core area for the development of new therapies for SLE. This study was undertaken to clarify the pathogenic mechanism involved and to identify new therapeutic targets, using a high-throughput screening platform to determine novel regulators that contribute to the overactivation of the type I IFN signaling pathway in SLE. Methods A high-throughput IFN-stimulated response element (ISRE)-luciferase assay was used to screen for candidate genes that regulate the IFN signaling pathway. Western blotting was used to confirm the regulatory function of CDK1. SYBR Green quantitative reverse transcriptase-polymerase chain reaction was used to detect the expression of individual IFN-stimulated genes (ISGs). The differential expression of CDK1 and ISGs in SLE patients and healthy controls was analyzed using RNA sequencing data and a microarray. Results The high-throughput ISRE-luciferase assay revealed that CDK1 enhanced type I IFN signaling. Consistent with this finding, CDK1 promoted the type I IFN-induced phosphorylation of STAT-1 and the up-regulated expression of ISGs. CDK1 expression was elevated in peripheral blood mononuclear cells (PBMCs) and kidney biopsy specimens from SLE patients and correlated positively with their IFN scores. A CDK1 inhibitor reduced the expression of ISGs in PBMCs from SLE patients and in renal cells from mice with lupus. Conclusion Our findings indicate that CDK1 is a positive regulator of the IFN signaling pathway. The overexpression of CDK1 might contribute to the abnormally amplified type I IFN signaling in SLE, and the inhibition of CDK1 could be used to down-regulate type I IFN signaling in SLE. [ABSTRACT FROM AUTHOR]

Objective Diffuse alveolar hemorrhage (DAH) is a rare but life-threatening complication of systemic lupus erythematosus (SLE). Pristane-treated B6 mice develop severe DAH within 2 weeks of treatment. MicroRNA-155 (miR-155) is a pleiotropic microRNA that plays a crucial role in the regulation of immune responses. Recent studies have revealed a pathogenic role of miR-155 in various autoimmune disorders. The purpose of this study was to examine the role of miR-155 in the development of DAH in pristane-induced lupus using miR-155-knockout (miR-155−/−) mice and miR-155 antagomir to silence miR-155. Methods DAH was induced by an intraperitoneal injection of 0.5 ml of pristane. MicroRNA-155 antagomir was administered intravenously to silence miR-155 expression. Lung tissues were collected for RNA extraction and were embedded in paraffin for sectioning. Gene expression profiling data were analyzed using Ingenuity Pathway Analysis. Real-time quantitative polymerase chain reaction analysis was used for single-gene validation. Luciferase reporter assay and argonaute 2 immunoprecipitation were performed for target validation. Results MicroRNA-155 expression was significantly increased during the development of DAH. Disease progression was reduced in miR-155−/− mice as well as by in vivo silencing of miR-155 using a miR-155 antagomir. MicroRNA-155 silencing dampened pristane-induced ectopic activation of multiple inflammatory pathways and reduced the expression of proinflammatory cytokines. Several negative regulators of NF-κB signaling were inhibited by pristane and were reactivated in miR-155−/− mice. In particular, the antiinflammatory factor peroxisome proliferator-activated receptor α was identified as a direct target of miR-155. Conclusion MicroRNA-155 promotes pristane-induced lung inflammation. It contributes to ectopic activation of NF-κB signaling pathways by targeting multiple negative regulators. MicroRNA-155 antagomir may be a promising therapeutic strategy for treating acute lung inflammation in lupus. [ABSTRACT FROM AUTHOR]

Objective Systemic lupus erythematosus (SLE) is characterized by the uncontrolled production of inflammatory cytokines, among which type I interferon (IFN) is recognized as a crucial pathogenic factor. The expression of microRNA-146a (miR-146a) is reduced in the white blood cells of SLE patients and accounts for their overactivated inflammatory responses. However, the mechanism of the reduction of miR-146a is still not fully understood. This study was undertaken to test whether the key pathogenic cytokine, type I IFN, is responsible for the dysregulation of miR-146a in SLE. Methods Gene and protein expression was measured in all cells by reverse transcription-quantitative polymerase chain reaction, Northern blotting, or Western blotting. In THP-1 cells, expression of monocyte chemotactic protein-induced protein 1 (MCPIP-1) was knocked down with a lentivirus encoding a short hairpin RNA targeting MCPIP1. The cells were pretreated with type I IFN and assessed for gene expression levels of miR-146a. White blood cells from patients with SLE were analyzed for the expression of the IFN-inducible genes MCPIP1 and miR-146a, and the gene expression data were compared for correlation. Results Pretreatment of THP-1 cells with type I IFN attenuated the induction of miR-146a posttranscriptionally, by down-regulating the expression of pre-miR-146a but not pri-miR-146a or its original unspliced transcript. Expression of MCPIP-1, which was enhanced by type I IFN, was found to be responsible for the inhibition of miR-146a. In white blood cells from patients with SLE, MCPIP1 expression was elevated, and its expression correlated positively with the IFN score and negatively with the miR-146a transcript level. Conclusion Type I IFN inhibits the maturation of miR-146a through the up-regulation of MCPIP-1, and thus contributes to the uncontrolled inflammation and excessive inflammatory gene expression in SLE. [ABSTRACT FROM AUTHOR]

Objective MicroRNAs (miRNAs) function to fine-tune the control of immune cell signaling. It is well established that there are abnormalities in the interleukin-2 (IL-2)-related signaling pathways in systemic lupus erythematosus (SLE). The miR-31 microRNA has been found to be markedly underexpressed in patients with SLE, and thus the present study was undertaken to investigate the role of miR-31 in IL-2 defects in lupus T cells. Methods Expression levels of miR-31 were quantitated using TaqMan miRNA assays. Transfection and stimulation of cultured cells followed by TaqMan quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and reporter gene assays were conducted to determine the biologic function of miR-31. NF-AT nuclear translocation and expression were quantitatively measured using an ImageStream cytometer. Bioinformatics analysis, small interfering RNA (siRNA) knockdown, and Western blotting were performed to validate miR-31 targets and effects. Results The expression of miR-31 was significantly decreased in lupus T cells, and this was positively correlated with the expression of IL-2. Overexpression of miR-31 in T cells increased the production of IL-2 by altering NF-AT nuclear expression and IL2 promoter activity, while knockdown of endogenous miR-31 reduced IL-2 production. RhoA expression was directly repressed by miR-31 in T cells. Of note, siRNA-mediated knockdown of RhoA enhanced IL2 promoter activity and, consequently, up-regulated IL-2 production. RhoA expression was consistently up-regulated and negatively correlated with the levels of miR-31 in lupus T cells. Manipulation of miR-31 expression in lupus T cells restored the expression of IL-2 at both the messenger RNA and protein levels. Conclusion MicroRNA-31 is a novel enhancer of IL-2 production during T cell activation. Dysregulation of miR-31 and its target, RhoA, could be a novel molecular mechanism underlying the IL-2 deficiency in patients with SLE. [ABSTRACT FROM AUTHOR]

Background and Aim: Calcium has been proposed as a mediator of the chemoprevention of colorectal cancer (CRC), but the comprehensive mechanism underlying this preventive effect is not yet clear. Hence, we conducted this study to evaluate the possible roles and mechanisms of calcium-mediated prevention of CRC induced by 1,2-dimethylhydrazine (DMH) in mice. Methods: For gene expression analysis, 6 non-tumor colorectal tissues of mice from the DMH + Calcium group and 3 samples each from the DMH and control groups were hybridized on a 4644 K Agilent whole genome oligo microarray, and selected genes were validated by real-time polymerase chain reaction (PCR). Functional analysis of the microarray data was performed using KEGG and Gene Ontology (GO) analyses. Hub genes were identified using Pathway Studio software. Results: The tumor incidence rates in the DMH and DMH + Calcium groups were 90% and 40%, respectively. Microarray gene expression analysis showed that S100a9, Defa20, Mmp10, Mmp7, Ptgs2, and Ang2 were among the most downregulated genes, whereas Per3, Tef, Rnf152, and Prdx6 were significantly upregulated in the DMH + Calcium group compared with the DMH group. Functional analysis showed that the Wnt, cell cycle, and arachidonic acid pathways were significantly downregulated in the DMH + Calcium group, and that the GO terms related to cell differentiation, cell cycle, proliferation, cell death, adhesion, and cell migration were significantly affected. Forkhead box M1 (FoxM1) and nuclear factor kappa-B (NF-kB) were considered as potent hub genes. Conclusion: In the DMH-induced CRC mouse model, comprehensive mechanisms were involved with complex gene expression alterations encompassing many altered pathways and GO terms. However, how calcium regulates these events remains to be studied. [ABSTRACT FROM AUTHOR]