Gene network analysis of bone marrow mononuclear cells reveals activation of multiple kinase pathways in human systemic lupus erythematosus

UDP-glucose ceramide glucosyltransferase specifically upregulated in plasmacytoid dendritic cells regulates type I interferon production upon CpG stimulation

Plasmacytoid dendritic cells (pDCs) are a distinct subset of DCs involved in immune regulation and antiviral immune responses. Recent studies have elucidated the metabolic profile of pDCs and reported that perturbations in amino acid metabolism can modulate their immune functions. Glycolipid metabolism is suggested to be highly active in pDCs; however, its significance remains unclear. In this study, bulk RNA-sequencing analysis confirmed the known pDC-marker expressions, including interleukin (IL)-3R (CD123), BDCA-2 (CD303), BDCA-4 (CD304), and toll-like receptor 9, compared with that of myeloid DCs (mDCs). Among the differentially expressed genes, UDP-glucose-ceramide glucosyltransferase (UGCG) expression was significantly upregulated in pDCs than in mDCs. Moreover, pDC-specific UGCG expression was observed at both the mRNA and protein levels in pDCs and pDC-like cell lines, including CAL-1 and PMDC05 cell lines. Pharmacological or clustered regularly interspaced palindromic repeat (CRISPR)/CRISPR-associated protein 9-mediated genetic inhibition of UGCG did not affect the pDC phenotype as evidenced by the persistent expression of IL-3R and BDCA-2 in pDC-like cell lines. However, UGCG knockout resulted in reduced type I interferon production in pDCs upon CpG activation. In addition, UGCG-knockout pDC-like cell lines exhibited reduced transduction by vesicular stomatitis virus-G pseudo-typed lentiviral vectors, suggesting that low UGCG expression hinders infectivity. Collectively, our findings suggest that pDC-specific UGCG expression is critical for cytokine production and antiviral immune responses in pDCs.

STATs, promising targets for the treatment of autoimmune and inflammatory diseases

Cytokines play a crucial role in the pathophysiology of autoimmune and inflammatory diseases, with over 50 cytokines undergoing signal transduction through the Signal Transducers and Activators of Transcription (STAT) signaling pathway. Recent studies have solidly confirmed the pivotal role of STATs in autoimmune and inflammatory diseases. Therefore, this review provides a detailed summary of the immunological functions of STATs, focusing on exploring their mechanisms in various autoimmune and inflammatory diseases. Additionally, with the rapid advancement of structural biology in the field of drug discovery, many STAT inhibitors have been identified using structure-based drug design strategies. In this review, we also examine the structures of STAT proteins and compile the latest research on STAT inhibitors currently being tested in animal models and clinical trials for the treatment of immunological diseases, which emphasizes the feasibility of STATs as promising therapeutic targets and provides insights into the design of the next generation of STAT inhibitors.

Exploring the shared molecular mechanisms between systemic lupus erythematosus and primary Sjögren's syndrome based on integrated bioinformatics and single-cell RNA-seq analysis

Background

Systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) are common systemic autoimmune diseases that share a wide range of clinical manifestations and serological features. This study investigates genes, signaling pathways, and transcription factors (TFs) shared between SLE and pSS.

Methods

Gene expression profiles of SLE and pSS were obtained from the Gene Expression Omnibus (GEO). Weighted gene co-expression network analysis (WGCNA) and differentially expressed gene (DEG) analysis were conducted to identify shared genes related to SLE and pSS. Overlapping genes were then subject to Gene Ontology (GO) and protein-protein interaction (PPI) network analyses. Cytoscape plugins cytoHubba and iRegulon were subsequently used to screen shared hub genes and predict TFs. In addition, gene set variation analysis (GSVA) and CIBERSORTx were used to calculate the correlations between hub genes and immune cells as well as related pathways. To confirm these results, hub genes and TFs were verified in microarray and single-cell RNA sequencing (scRNA-seq) datasets.

Results

Following WGCNA and limma analysis, 152 shared genes were identified. These genes were involved in interferon (IFN) response and cytokine-mediated signaling pathway. Moreover, we screened six shared genes, namely IFI44L, ISG15, IFIT1, USP18, RSAD2 and ITGB2, out of which three genes, namely IFI44L, ISG15 and ITGB2 were found to be highly expressed in both microarray and scRNA-seq datasets. IFN response and ITGB2 signaling pathway were identified as potentially relevant pathways. In addition, STAT1 and IRF7 were identified as common TFs in both diseases.

Conclusion

This study revealed IFI44L, ISG15 and ITGB2 as the shared genes and identified STAT1 and IRF7 as the common TFs of SLE and pSS. Notably, the IFN response and ITGB2 signaling pathway played vital roles in both diseases. Our study revealed common pathogenetic characteristics of SLE and pSS. The particular roles of these pivotal genes and mutually overlapping pathways may provide a basis for further mechanistic research.

A Comparative Study on the Incidence, Aggravation, and Remission of Lupus Nephritis Based on iTRAQ Technology

AIM AND OBJECTIVE

Lupus nephritis (LN) is one of the major complications of systemic lupus erythematosus (SLE). The specific mechanisms of pathogenesis, aggravation, and remission processes in LN have not been clarified but is of great need in the clinic. Using isobaric tags for relative and absolute quantitation (iTRAQ) technology to screen the functional proteins of LN in mice. Especially under intervention factors of lipopolysaccharide (LPS) and dexamethasone.

METHODS

Mrl-lps mice were intervened with LPS, dexamethasone, and normal saline (NS) using intraperitoneal injection, and c57 mice intervened with NS as control. The anti-ANA antibody enzyme-linked immunosorbent assay (ELISA) was used to verify disease severity. Kidney tissue is collected and processed for iTRAQ to screen out functional proteins closely related to the onset and development of LN. Western blot method and rt-PCR (real-time Polymerase Chain Reaction) were used for verification.

RESULTS

We identified 136 proteins that marked quantitative information. Among them, Hp, Igkv8-27, Itgb2, Got2, and Pcx proteins showed significant abnormal manifestations.

CONCLUSION

Using iTRAQ methods, the functional proteins Hp, Igkv8-27, Itgb2, Got2, and Pcx were screened out for a close relationship with the pathogenesis and development of LN, which is worth further study.

Cutaneous and systemic connections in lupus

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multiple manifestations, with a majority of SLE patients having cutaneous involvement. Despite ongoing research, the relationship between SLE and cutaneous lupus erythematosus (CLE) pathogeneses remains unknown. This review will compare advances in understanding the cause and pathogenesis of SLE and CLE.

RECENT FINDINGS

Recently, mechanisms by which immune cell populations contribute to the pathogenesis of SLE and CLE have been queried. Studies have pointed to transitional B cells and B-cell activating factor (BAFF) signaling as potential drivers of SLE and CLE, with belimumab clinical data supporting these hypotheses. Ustekinumab trials and an exciting regulatory T cell (Treg) adoptive transfer in an SLE patient with cutaneous disease have suggested a role for T-cell-targeted therapies. The theory that neutrophil extracellular traps may be a source of autoantigens in SLE remains controversial, while neutrophils have been suggested as early drivers of cutaneous disease. Finally, plasmacytoid dendritic cells (pDCs) have been studied as a potential therapeutic target in SLE, and anti-blood DC antigen (anti-BDCA) antibody clinical trials have shown promise in treating cutaneous disease.

SUMMARY

Although recent findings have contributed to understanding SLE and CLE pathogenesis, the mechanistic link between these diseases remains an area requiring further research.

Role of Forkhead box O3a transcription factor in autoimmune diseases

Forkhead box O3a (FOXO3a) transcription factor, the most important member of Forkhead box O family, is closely related to cell proliferation, apoptosis, autophagy, oxidative stress and aging. The downregulation of FOXO3a has been verified to be associated with the poor prognosis, severer malignancy and chemoresistance in several human cancers. The activity of FOXO3a mainly regulated by phosphorylation of protein kinase B. FOXO3a plays a vital role in promoting the apoptosis of immune cells. FOXO3a could also modulate the activation, differentiation and function of T cells, regulate the proliferation and function of B cells, and mediate dendritic cells tolerance and immunity. FOXO3a accommodates the immune response through targeting nuclear factor kappa-B and FOXP3, as well as regulating the expression of cytokines. Besides, FOXO3a participates in intercellular interactions. FOXO3a inhibits dendritic cells from producing interleukin-6, which inhibits B-cell lymphoma-2 (BCL-2) and BCL-XL expression, thereby sparing resting T cells from apoptosis and increasing the survival of antigen-stimulated T cells. Recently, plentiful evidences further illustrated the significance of FOXO3a in the pathogenesis of autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, ankylosing spondylitis, myositis, multiple sclerosis, and systemic sclerosis. In this review, we focused on the biological function of FOXO3a and related signaling pathways regarding immune system, and summarized the potential role of FOXO3a in the pathogenesis, progress and therapeutic potential of autoimmune diseases.

Immune cell infiltration characteristics and related core genes in lupus nephritis: results from bioinformatic analysis

BACKGROUND

Lupus nephritis (LN) is a common complication of systemic lupus erythematosus that presents a high risk of end-stage renal disease. In the present study, we used CIBERSORT and gene set enrichment analysis (GSEA) of gene expression profiles to identify immune cell infiltration characteristics and related core genes in LN.

RESULTS

Datasets from the Gene Expression Omnibus, GSE32591 and GSE113342, were downloaded for further analysis. The GSE32591 dataset, which included 32 LN glomerular biopsy tissues and 14 glomerular tissues from living donors, was analyzed by CIBERSORT. Different immune cell types in LN were analyzed by the Limma software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis based on GSEA were performed by clusterProfiler software. Lists of core genes were derived from Spearman correlation between the most significant GO term and differentially expressed immune cell gene from CIBERSORT. GSE113342 was employed to validate the association between selected core genes and clinical manifestation. Five types of immune cells revealed important associations with LN, and monocytes emerged as having the most prominent differences. GO and KEGG analyses indicated that immune response pathways are significantly enriched in LN. The Spearman correlation indicated that 15 genes, including FCER1G, CLEC7A, MARCO, CLEC7A, PSMB9, and PSMB8, were closely related to clinical features.

CONCLUSIONS

This study is the first to identify immune cell infiltration with microarray data of glomeruli in LN by using CIBERSORT analysis and provides novel evidence and clues for further research of the molecular mechanisms of LN.

Interferon (IFN)-inducible Absent in Melanoma 2 proteins in the negative regulation of the type I IFN response: Implications for lupus nephritis

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that exhibits a strong female bias (female-to-male ratio 9:1) in patients. Further, 40-60% SLE patients develop lupus nephritis (LN), which significantly increases the mortality rates. The failure of current therapies to adequately treat LN in patients reflects an incomplete understanding of the disease pathogenesis. Notably, a chronic increase in serum interferon-α (IFN-α) activity is a heritable risk factor to develop SLE. Accordingly, blood cells from most SLE patients with an active disease exhibit an increase in the expression of the type I IFN (IFN-α/β)-stimulated genes (ISGs, also referred to as "IFN-signature"), a type I IFN response. Further, LN patients during renal flares also exhibit an "IFN-signature" in renal biopsies. Therefore, an improved understanding of the regulation of type I IFNs expression is needed. Basal levels of the IFN-β through "priming" of IFN-α producing cells augment the expression of the IFN-α genes. Of interest, recent studies have indicated a role for the type I IFN-inducible Absent in Melanoma 2 proteins (the murine Aim2 and human AIM2) in the negative regulation of the type I IFN response through inflammasome-dependent and independent mechanisms. Further, an increase in the expression of Aim2 and AIM2 proteins in kidney and renal macrophages associated with the development of nephritis. Therefore, we discuss the role of Aim2/AIM2 proteins in the regulation of type I IFNs and LN. An improved understanding of the mechanisms by which the Absent in Melanoma 2 proteins suppress the type I IFN response and modulate nephritis is key to identify novel therapeutic targets to treat a group of LN patients.

REDD1/autophagy pathway promotes thromboinflammation and fibrosis in human systemic lupus erythematosus (SLE) through NETs decorated with tissue factor (TF) and interleukin-17A (IL-17A)

OBJECTIVES

The release of neutrophil extracellular traps (NETs) represents a novel neutrophil effector function in systemic lupus erythematosus (SLE) pathogenesis. However, the molecular mechanism underlying NET release and how NETs mediate end-organ injury in SLE remain elusive.

METHODS

NET formation and NET-related proteins were assessed in the peripheral blood and biopsies from discoid lupus and proliferative nephritis, using immunofluorescence, immunoblotting, quantitative PCR and ELISA. Autophagy was assessed by immunofluorescence and immunoblotting. The functional effects of NETs in vitro were assessed in a primary fibroblast culture.

RESULTS

Neutrophils from patients with active SLE exhibited increased basal autophagy levels leading to enhanced NET release, which was inhibited in vitro by hydroxychloroquine. NETosis in SLE neutrophils correlated with increased expression of the stress-response protein REDD1. Endothelin-1 (ET-1) and hypoxia-inducible factor-1α (HIF-1α) were key mediators of REDD1-driven NETs as demonstrated by their inhibition with bosentan and L-ascorbic acid, respectively. SLE NETs were decorated with tissue factor (TF) and interleukin-17A (IL-17A), which promoted thrombin generation and the fibrotic potential of cultured skin fibroblasts. Notably, TF-bearing and IL-17A-bearing NETs were abundant in discoid skin lesions and in the glomerular and tubulointerstitial compartment of proliferative nephritis biopsy specimens.

CONCLUSIONS

Our data suggest the involvement of REDD1/autophagy/NET axis in end-organ injury and fibrosis in SLE, a likely candidate for repositioning of existing drugs for SLE therapy. Autophagy-mediated release of TF-bearing and IL-17A-bearing NETs provides a link between thromboinflammation and fibrosis in SLE and may account for the salutary effects of hydroxychloroquine.

Foxo3 Promotes Apoptosis of B Cell Receptor-Stimulated Immature B Cells, Thus Limiting the Window for Receptor Editing

Central tolerance checkpoints are critical for the elimination of autoreactive B cells and the prevention of autoimmunity. When autoreactive B cells encounter their Ag at the immature B cell stage, BCR cross-linking induces receptor editing, followed by apoptosis if edited cells remain autoreactive. Although the transcription factor Foxo1 is known to promote receptor editing, the role of the related factor Foxo3 in central B cell tolerance is poorly understood. We find that BCR-stimulated immature B cells from Foxo3-deficient mice demonstrate reduced apoptosis compared with wild type cells. Despite this, Foxo3^-/- mice do not develop increased autoantibodies. This suggests that the increased survival of Foxo3^-/- immature B cells allows additional rounds of receptor editing, resulting in more cells "redeeming" themselves by becoming nonautoreactive. Indeed, increased Igλ usage and increased recombining sequence recombination among Igλ-expressing cells were observed in Foxo3^-/- mice, indicative of increased receptor editing. We also observed that deletion of high-affinity autoreactive cells was intact in the absence of Foxo3 in the anti-hen egg lysozyme (HEL)/membrane-bound HEL model. However, Foxo3 levels in B cells from systemic lupus erythematosus (SLE) patients were inversely correlated with disease activity and reduced in patients with elevated anti-dsDNA Abs. Although this is likely due in part to increased B cell activation in these SLE patients, it is also possible that low-affinity B cells that remain autoreactive after editing may survive inappropriately in the absence of Foxo3 and become activated to secrete autoantibodies in the context of other SLE-associated defects.

S3I-201 ameliorates tubulointerstitial lesion of the kidneys in MRL/lpr mice

It is high incidence of tubulointerstitial lesion (TIL) in lupus nephritis (LN) and TIL can affect the prognosis of patients with LN. Signal transducer and activator of transcription (STAT) 3 was activated in LN and STAT3 inhibition could delay the onset of LN. Here, we evaluated the role of a well-known STAT3 inhibitor, S3I-201, on TIL in lupus nephritis. STAT3 was activated in MRL/lpr mice (a mouse model of lupus nephritis), and treatment with S3I-201 inhibited the activation of it. The level of 24-h urine protein and nitrogen urea increased in MRL/lpr mice and adminstration of S3I-201 reduced the level of urinary protein. In addition, S3I-201 attenuated the expression of α-smooth muscle actin (α-SMA), Fibronectin (FN) proteins, as well as the expression of monocyte chemotactic factor-1 (MCP-1) and intercellular adhesion molecule (ICAM-1). However, the expression of E-cadherin improved when treatment with S3I-201. These results revealed that the activation of STAT3 mediates tubulointerstitial lesion in mice with LN. S3I-201, by suppressing STAT3 activity, has therapeutic effect in lupus nephritis.

STAT3-mediated epigenetic silencing of FOXP3 in LADA T cells is regulated through HDAC5 and DNMT1

In LADA patients, Tregs are reduced and FOXP3 is downregulated in CD4+ T cells, but the etiology remains unclear. Our study included in 20 LADA patients and 20 healthy control patients. qRT-PCR results showed that STAT3, HDAC3, HDAC5, SIRT1, DNMT1 and DNMT3b mRNAs were significantly upregulated in LADA CD4+ T cells than controls, while FOXP3 mRNA significantly decreased. p-STAT3, STAT3, DNMT1 and DNMT3b expressions were increased demonstrated by western blot. ChIP-PCR suggested that p-STAT3 binds to the Foxp3 promoter, meanwhile, histone H3 acetylation at K9 and K14 of FOXP3 promoter were significantly lower than controls. Luciferase reporter assay showed that ectopic STAT3 expression significantly reduced FOXP3 promoter activities. The Foxp3 promoter was significantly hypermethylated in LADA than controls. LADA patients showed stronger binding of p-STAT3, HDAC5 and DNMT1 than controls using CHIP. These findings reveal a crucial role of STAT3 in regulating the epigenetic status of T cells in LADA.

Aberrant T Cell Signaling and Subsets in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic multi-organ debilitating autoimmune disease, which mainly afflicts women in the reproductive years. A complex interaction of genetics, environmental factors and hormones result in the breakdown of immune tolerance to "self" leading to damage and destruction of multiple organs, such as the skin, joints, kidneys, heart and brain. Both innate and adaptive immune systems are critically involved in the misguided immune response against self-antigens. Dendritic cells, neutrophils, and innate lymphoid cells are important in initiating antigen presentation and propagating inflammation at lymphoid and peripheral tissue sites. Autoantibodies produced by B lymphocytes and immune complex deposition in vital organs contribute to tissue damage. T lymphocytes are increasingly being recognized as key contributors to disease pathogenesis. CD4 T follicular helper cells enable autoantibody production, inflammatory Th17 subsets promote inflammation, while defects in regulatory T cells lead to unchecked immune responses. A better understanding of the molecular defects including signaling events and gene regulation underlying the dysfunctional T cells in SLE is necessary to pave the path for better management, therapy, and perhaps prevention of this complex disease. In this review, we focus on the aberrations in T cell signaling in SLE and highlight therapeutic advances in this field.

The Potential Role of Trained Immunity in Autoimmune and Autoinflammatory Disorders

During induction of trained immunity, monocytes and macrophages undergo a functional and transcriptional reprogramming toward increased activation. Important rewiring of cellular metabolism of the myeloid cells takes place during induction of trained immunity, including a shift toward glycolysis induced through the mTOR pathway, as well as glutaminolysis and cholesterol synthesis. Subsequently, this leads to modulation of the function of epigenetic enzymes, resulting in important changes in chromatin architecture that enables increased gene transcription. However, in addition to the beneficial effects of trained immunity as a host defense mechanism, we hypothesize that trained immunity also plays a deleterious role in the induction and/or maintenance of autoimmune and autoinflammatory diseases if inappropriately activated.

Bioinformatic approaches to interrogating vitamin D receptor signaling

Bioinformatics applies unbiased approaches to develop statistically-robust insight into health and disease. At the global, or "20,000 foot" view bioinformatic analyses of vitamin D receptor (NR1I1/VDR) signaling can measure where the VDR gene or protein exerts a genome-wide significant impact on biology; VDR is significantly implicated in bone biology and immune systems, but not in cancer. With a more VDR-centric, or "2000 foot" view, bioinformatic approaches can interrogate events downstream of VDR activity. Integrative approaches can combine VDR ChIP-Seq in cell systems where significant volumes of publically available data are available. For example, VDR ChIP-Seq studies can be combined with genome-wide association studies to reveal significant associations to immune phenotypes. Similarly, VDR ChIP-Seq can be combined with data from Cancer Genome Atlas (TCGA) to infer the impact of VDR target genes in cancer progression. Therefore, bioinformatic approaches can reveal what aspects of VDR downstream networks are significantly related to disease or phenotype.

Reno-protective effect and mechanism study of Huang Lian Jie Du Decoction on lupus nephritis MRL/lpr mice

BACKGROUND

Huang Lian Jie Du Decoction (HLJDD), a very famous traditional Chinese medicinal prescription, has been used for heat dissipation and detoxification in China. This study was aimed to evaluate the reno-protective effects of HLJDD against lupus nephritis (LN) in vivo in MRL/lpr mice.

METHODS

Animals were administered orally every day for eight consecutive weeks except the mice of normal group and model group. Organ indexes, serum interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-gamma (IFN-γ) and the anti-double stranded DNA (anti-dsDNA) antibody were tested, respectively. Creatinine (Cr), blood urea nitrogen (BUN) and urine protein were measured for renal function evaluation. The expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT 3) in kidney tissue was observed by western blot (WB) and immunohistochemical (IHC) method. Meanwhile, histopathological changes in the renal were studied by hematoxylin-eosin (H&E) staining.

RESULTS

The mice of HLJDD-treated group exhibited a significant reduced mortality (p < 0.05), serum anti-dsDNA level (p < 0.05) and renal immune complex deposition (p < 0.05), compared with the untreated MRL/lpr mice. In addition, HLJDD treatment remarkably reduced the levels of BUN, Cr, proteinuria (p < 0.01) and the levels of inflammatory cytokines such as IL-6, IL-10 and IFN-γ (p < 0.01). Moreover, HLJDD significantly suppressed the phosphorylations of STAT 3 (p < 0.05) and the renal pathological changes.

CONCLUSIONS

The study implied that HLJDD may be a potential agent for the therapy of LN, and the down-regulated p-STAT 3 expression suggesting that it may be one of the LN therapy targets for HLJDD.

STAT3 Signaling in B Cells Is Critical for Germinal Center Maintenance and Contributes to the Pathogenesis of Murine Models of Lupus

Ab maturation as well as memory B and plasma cell differentiation occur primarily in the germinal centers (GCs). Systemic lupus erythematosus (SLE) may develop as a result of enhanced GC activity. Previous studies have shown that the dysregulated STAT3 pathway is linked to lupus pathogenesis. However, the exact role of STAT3 in regulating SLE disease progression has not been fully understood. In this study, we demonstrated that STAT3 signaling in B cells is essential for GC formation and maintenance as well as Ab response. Increased cell apoptosis and downregulated Bcl-xL and Mcl-1 antiapoptotic gene expression were found in STAT3-deficient GC B cells. The follicular helper T cell response positively correlated with GC B cells and was significantly decreased in immunized B cell STAT3-deficient mice. STAT3 deficiency also led to the defect of plasma cell differentiation. Furthermore, STAT3 deficiency in autoreactive B cells resulted in decreased autoantibody production. Results obtained from B cell STAT3-deficient B6.MRL/lpr mice suggest that STAT3 signaling significantly contributes to SLE pathogenesis by regulation of GC reactivity, autoantibody production, and kidney pathology. Our findings provide new insights into the role of STAT3 signaling in the maintenance of GC formation and GC B cell differentiation and identify STAT3 as a novel target for treatment of SLE.

Signal transducer and activator of transcription (STAT) 3 inhibition delays the onset of lupus nephritis in MRL/lpr mice

The transcription factor STAT3 is overexpressed and hyperactivated in T cells from SLE patients. STAT3 plays a central role in T cell differentiation into Th17 and T follicular helper cells, two subsets that orchestrate autoimmune responses in SLE. Moreover, STAT3 is important in chemokine-mediated T cell migration. To better understand its role in SLE, we inhibited STAT3 in lupus-prone mice using the small molecule Stattic. Stattic-treated mice exhibited delayed onset of proteinuria (3 weeks later than controls), and had lower levels of anti-dsDNA antibodies and inflammatory cytokines. Inhibitor treatment reduced lymphadenopathy, resulted in a 3-fold decrease in total T cell number, and a 4-fold decrease in the numbers of T follicular helper cells. In vitro experiments showed that Stattic-treated T cells exhibited decreased proliferation and a decrease in ability to migrate to CXCL12. We propose that STAT3 inhibition represents a therapeutic target in SLE, particularly lupus nephritis.

Role of neutrophils in systemic autoimmune diseases

Neutrophils have emerged as important regulators of innate and adaptive immune responses. Recent evidence indicates that neutrophils display marked abnormalities in phenotype and function in various systemic autoimmune diseases, and may play a central role in initiation and perpetuation of aberrant immune responses and organ damage in these conditions. This review discusses the putative roles that neutrophils and aberrant neutrophil cell death play in the pathogenesis of various systemic autoimmune diseases, including systemic lupus erythematosus, small vessel vasculitis and rheumatoid arthritis.

Gene expression and regulation in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is the prototypic systemic autoimmune disease. Genome-wide (GW) association studies have identified more than 40 disease-associated loci, together accounting for only 10-20% of disease heritability. Gene expression represents the intermediate phenotype between DNA and disease phenotypic variation, and provides insights regarding genetic and epigenetic effects. We review data on gene expression and regulation in SLE by our group and other investigators.

MATERIALS AND METHODS

Systematic PubMed search for GW expression studies in SLE published since the year 2000.

RESULTS

Deregulation of genes involved in type I interferon signaling is a consistent finding in the peripheral blood of active and severe SLE patients. Upregulation of granulocyte-specific transcripts especially in bone marrow mononuclear cells (BMMCs), and of myeloid lineage transcripts in lupus nephritis, provide evidence for pathogenic role of these cells. Gene network analysis in BMMCs identified central gene regulators which could represent therapeutic targets and a high similarity between SLE and non-Hodgkin lymphoma providing a molecular basis for the reported association of the two diseases. Gene expression abnormalities driven by deregulated expression of certain microRNAs in SLE contribute to interferon production, T- and B-cell hyperactivity, DNA hypomethylation, and defective tissue response to injury. Methylation arrays have revealed alterations in white blood cell DNA methylation in SLE suggesting an important role of epigenetics and the environment.

CONCLUSIONS

Gene expression studies have contributed to the characterization of pathogenic processes in SLE. Integrated approaches utilizing genetic variation, transcriptome and epigenome profiling will facilitate efforts towards a molecular-based disease taxonomy.

Altered AKT1 and MAPK1 gene expression on peripheral blood mononuclear cells and correlation with T-helper-transcription factors in systemic lupus erythematosus patients

Kinases have been implicated in the immunopathological mechanisms of Systemic Lupus Erythematosus (SLE). v-akt murine-thymoma viral-oncogene-homolog 1 (AKT1) and mitogen-activated-protein-kinase 1 (MAPK1) gene expressions in peripheral mononuclear cells from thirteen SLE patients with inactive or mild disease were evaluated using quantitative real-time reverse-transcription polymerase-chain-reaction and analyzed whether there was any correlation with T-helper (Th) transcription factors (TF) gene expression, cytokines, and S100A8/S100A9-(Calprotectin). Age- and gender-matched thirteen healthy controls were examined. AKT1 and MAPK1 expressions were upregulated in SLE patients and correlated with Th17-(Retinoic acid-related orphan receptor (ROR)-C), T-regulatory-(Treg)-(Transforming Growth Factor Beta (TGFB)-2), and Th2-(interleukin (IL)-5)-related genes. MAPK1 expression correlated with Th1-(IL-12A, T-box TF-(T-bet)), Th2-(GATA binding protein-(GATA)-3), and IL-10 expressions. IL-10 expression was increased and correlated with plasma Tumor Necrosis Factor (TNF)-α and Th0-(IL-2), Th1-(IL-12A, T-bet), GATA3, Treg-(Forkhead/winged-helix transcription factor- (FOXP)-3), and IL-6 expressions. FOXP3 expression, FOXP3/RORC, and FOXP3/GATA3 expression ratios were increased. Plasma IL-1β, IL-12(p70), Interferon-(IFN)-γ, and IL-6 cytokines were augmented. Plasma IL-1β, IL-6, IL-2, IFN-γ, TNF-α, IL-10, and IL-13 correlated with C-reactive protein, respectively. Increased Calprotectin correlated with neutrophils. Conclusion, SLE patients presented a systemic immunoinflammatory activity, augmented AKT1 and MAPK1 expressions, proinflammatory cytokines, and Calprotectin, together with increased expression of Treg-related genes, suggesting a regulatory feedback opposing the inflammatory activity.

Role of the JNK pathway in human diseases

The c-Jun-NH(2)-terminal kinase (JNK) signaling pathway plays a critical role in regulating cell fate, being implicated in a multitude of diseases ranging from cancer to neurological and immunological/inflammatory conditions. Not surprisingly, therefore, it has been sought after for therapeutic intervention, and its inhibition has been shown to ameliorate many pathological conditions in experimental systems, paving the way for initial clinical trials. However, the fundamental problem in fully harnessing the potential provided by the JNK pathway has been the lack of specificity, due to the multiple JNK forms that are involved in multiple cellular processes in various cell types. Moreover, lack of sufficient knowledge of all JNK-interacting proteins and substrates has also hindered progress. This review will therefore focus on the role of the JNKs in human diseases and appraise the efforts to inhibit JNK signaling to ameliorate disease conditions, assessing potential challenges and providing insights into possible future directions to efficiently target this pathway for therapeutic use.

Pulmonary microRNA profiling in a mouse model of ventilator-induced lung injury

The aim of this study was to investigate the changes induced by high tidal volume ventilation (HVTV) in pulmonary expression of micro-RNAs (miRNAs) and identify potential target genes and corresponding miRNA-gene networks. Using a real-time RT-PCR-based array in RNA samples from lungs of mice subjected to HVTV for 1 or 4 h and control mice, we identified 65 miRNAs whose expression changed more than twofold upon HVTV. An inflammatory and a TGF-β-signaling miRNA-gene network were identified by in silico pathway analysis being at highest statistical significance (P = 10(-43) and P = 10(-28), respectively). In the inflammatory network, IL-6 and SOCS-1, regulated by miRNAs let-7 and miR-155, respectively, appeared as central nodes. In TGF-β-signaling network, SMAD-4, regulated by miR-146, appeared as a central node. The contribution of miRNAs to the development of lung injury was evaluated in mice subjected to HVTV treated with a precursor or antagonist of miR-21, a miRNA highly upregulated by HVTV. Lung compliance was preserved only in mice treated with anti-miR-21 but not in mice treated with pre-miR-21 or negative-control miRNA. Both alveolar-arterial oxygen difference and protein levels in bronchoalveolar lavage were lower in mice treated with anti-miR-21 than in mice treated with pre-miR-21 or negative-control miRNA (D(A-a): 66 ± 27 vs. 131 ± 22, 144 ± 10 mmHg, respectively, P < 0.001; protein concentration: 1.1 ± 0.2 vs. 2.3 ± 1, 2.1 ± 0.4 mg/ml, respectively, P < 0.01). Our results show that HVTV induces changes in miRNA expression in mouse lungs. Modulation of miRNA expression can affect the development of HVTV-induced lung injury.

Germline mutations in MSR1, ASCC1, and CTHRC1 in patients with Barrett esophagus and esophageal adenocarcinoma

CONTEXT

Barrett esophagus (BE) occurs in 1% to 10% of the general population and is believed to be the precursor of esophageal adenocarcinoma (EAC). The incidence of EAC has increased 350% in the last 3 decades without clear etiology. Finding predisposition genes may improve premorbid risk assessment, genetic counseling, and management. Genome-wide multiplatform approaches may lead to the identification of genes important in BE/EAC development.

OBJECTIVE

To identify risk alleles or mutated genes associated with BE/EAC.

DESIGN, SETTING, AND PATIENTS

Model-free linkage analyses of 21 concordant-affected sibling pairs with BE/EAC and 11 discordant sibling pairs (2005-2006). Significant germline genomic regions in independent prospectively accrued series of 176 white patients with BE/EAC and 200 ancestry-matched controls (2007-2010) were validated and fine mapped. Integrating data from these significant genomic regions with somatic gene expression data from 19 BE/EAC tissues yielded 12 "priority" candidate genes for mutation analysis (2010). Genes that showed mutations in cases but not in controls were further screened in an independent prospectively accrued validation series of 58 cases (2010).

MAIN OUTCOME MEASURES

Identification of germline mutations in genes associated with BE/EAC cases. Functional interrogation of the most commonly mutated gene.

RESULTS

Three major genes, MSR1, ASCC1, and CTHRC1 were associated with BE/EAC (all P < .001). In addition, 13 patients (11.2%) with BE/EAC carried germline mutations in MSR1, ASCC1, or CTHRC1. MSR1 was the most frequently mutated, with 8 of 116 (proportion, 0.069; 95% confidence interval [CI], 0.030-0.130; P < .001) cases with c.877C>T (p.R293X). An independent validation series confirmed germline MSR1 mutations in 2 of 58 cases (proportion, 0.035; 95% CI, 0.004-0.120; P = .09). MSR1 mutation resulted in CCND1 up-regulation in peripheral-protein lysate. Immunohistochemistry of BE tissues in MSR1-mutation carriers showed increased nuclear expression of CCND1.

CONCLUSION

MSR1 was significantly associated with the presence of BE/EAC in derivation and validation samples, although it was only present in a small percentage of the cases.