Autoimmune Mouse Model Research Articles

Mine-site derived particulate matter exposure exacerbates neurological and pulmonary inflammatory outcomes in an autoimmune mouse model

ABSTRACT The Southwestern United States has a legacy of industrial mining due to the presence of rich mineral ore deposits. The relationship between environmental inhaled particulate matter (PM) exposures and neurological outcomes within an autoimmune context is understudied. The aim of this study was to compare two regionally-relevant dusts from high-priority abandoned mine-sites, Claim 28 PM, from Blue Gap Tachee, AZ and St. Anthony mine PM, from the Pueblo of Laguna, NM and to expose autoimmune-prone mice (NZBWF1/J). Mice were randomly assigned to one of three groups (n = 8/group): DM (dispersion media, control), Claim 28 PM, or St. Anthony PM, subjected to oropharyngeal aspiration of (100 µg/50 µl), once per week for a total of 4 consecutive doses. A battery of immunological and neurological endpoints was assessed at 24 weeks of age including: bronchoalveolar lavage cell counts, lung gene expression, brain immunohistochemistry, behavioral tasks and serum autoimmune biomarkers. Bronchoalveolar lavage results demonstrated a significant increase in number of polymorphonuclear neutrophils following Claim 28 and St. Anthony mine PM aspiration. Lung mRNA expression showed significant upregulation in CCL-2 and IL-1ß following St. Anthony mine PM aspiration. In addition, neuroinflammation was present in both Claim 28 and St. Anthony mine-site derived PM exposure groups. Behavioral tasks resulted in significant deficits as determined by Y-maze new arm frequency following Claim 28 aspiration. Neutrophil elastase was significantly upregulated in the St. Anthony mine exposure group. Interestingly, there were no significant changes in serum autoantigens suggesting systemic inflammatory effects may be mediated through other molecular mechanisms following low-dose PM exposures.

The effect of Bu Shen Huo Xue Tang on autoimmune premature ovarian insufficiency via Modulation of the Nrf2/Keap1 signaling pathway in mice

Ethnopharmacological relevanceBu Shen Huo Xue Tang (BSHXT) is a traditional Chinese medicine formula that is clinically used in the treatment of premature ovarian insufficiency (POI). However, its therapeutic mechanism remains unclear. Aim of the studyThis study aimed to investigate the underlying molecular mechanism of pharmacological activity of BSHXT, via the Nrf2/Keap1 signaling pathway, in the treatment of autoimmune POI. Materials and methodsThe chemical composition of BSHXT was analyzed using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry. The autoimmune POI mouse model was induced by immunizing mice twice, with zona pellucida (ZP) glycoprotein 3 antigen. The autoimmune POI mice were continuously administered BSHXT for 28 days. Body weight and organ indices were recorded. The pathological morphology of the ovaries was observed. The estrous cycle of each mouse was recorded. Immunofluorescence assay was used to detect the levels of ZP antibodies in the mouse ovaries. The levels of ZP antibodies, follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH), estradiol (E2), luteinizing hormone (LH), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured. The expression of genes and proteins involved in the Nrf2/Keap1 signaling pathway were measured by Q-PCR and IHC, respectively. ResultsTwenty-one compounds were identified in the BSHXT water extract. BSHXT was found to increase the body weight and ovarian index, improve ovarian function, and reduce disorders in the estrus cycle. It also reduced the expression of ZP antibodies in the ovaries and serum of POI mice. BSHXT significantly increased E2 and AMH levels and decreased FSH and LH levels. It also increased the levels of SOD, and reduced MDA levels. The levels of Nrf2 and Keap1 were also increased, and the expression of Nrf2, HO-1 and NQO1 genes was upregulated. ConclusionsBSHXT has a therapeutic effect on autoimmune POI in mice, which may be a result of the enhanced antioxidant capacity and activation of the Nrf2/Keap1 signaling pathway. BSHXT is a good drug candidate for use as a protective agent for POI and may be used in clinical practice.

Castrated autoimmune glomerulonephritis mouse model shows attenuated glomerular sclerosis with altered parietal epithelial cell phenotype.

Sex hormones help in maintaining proper immunity as well as renal homeostasis in mammals, and these multi-functional properties characterize the onset of sex-dependent diseases. To clarify the contribution of sex hormones to autoimmune disease-related renal pathogenesis, BXSB/MpJ-Yaa was investigated as a murine autoimmune glomerulonephritis model. BXSB/MpJ-Yaa and its wild-type, BXSB/MpJ-Yaa+ were castrated or sham-operated at three weeks and examined until six months of age. Both castrated strains showed significantly lower serum testosterone levels and body weights than sham-operated mice. Castration did not change the disease phenotypes in BXSB/MpJ-Yaa+. At three months, both sham-operated and castrated BXSB/MpJ-Yaa manifested splenomegaly, autoantibody production, and glomerulonephritis, and castrated BXSB/MpJ-Yaa tended to show heavier spleen weights than the sham-operated group. At six months, both the treated BXSB/MpJ-Yaa showed equivalent autoimmune disease conditions; however, castrated mice clearly showed milder glomerular sclerotic lesions than the sham-operated groups. Urinary albumin excretion in castrated BXSB/MpJ-Yaa was significantly milder than in sham-operated mice at four months, but those of both the treated BXSB/MpJ-Yaa were comparable at six months. The examined renal histopathological indices in parietal epithelial cells were remarkably altered by castration. Briefly, castration decreased the height of parietal epithelial cells and total parietal epithelial cell number in BXSB/MpJ-Yaa at six months. For immunostaining, parietal epithelial cells facing the injured glomeruli of BXSB/MpJ-Yaa expressed CD44, an activated parietal epithelial cell marker, and CD44-positive parietal epithelial cells showed nuclear localization of the androgen receptor and proliferation marker Ki67. CD44- or Ki67-positive parietal epithelial cells were significantly fewer in castrated group than in sham-operated BXSB/MpJ-Yaa at six months. Further, quantitative indices for CD44-positive parietal epithelial cell number and frequency in renal corpuscles positively correlated with glomerular sclerotic severity in BXSB/MpJ-Yaa. In conclusion, androgen seemed to have an effect on both systemic immunity and renal morpho-function; however, the effect on the latter could be more clearly observed in BXSB/MpJ-Yaa, as parietal epithelial cell activation resulted in glomerular sclerosis.

Flow Cytometric Characterization of Murine B Cell Development.

Extensive studies have characterized the development and differentiation of murine B cells in secondary lymphoid organs. Antibodies secreted by B cells have been isolated and developed into well-established therapeutics. Validation of murine B cell development, in the context of autoimmune prone mice, or in mice with modified immune systems, is a crucial component of developing or testing therapeutic agents in mice and is an appropriate use of flow cytometry. Well established B cell flow cytometric parameters can be used to evaluate B cell development in the murine peritoneum, bone marrow, and spleen, but a number of best practices must be adhered to. In addition, flow cytometric analysis of B cell compartments should also complement additional readouts of B cell development. Data generated using this technique can further our understanding of wild type, autoimmune prone mouse models as well as humanized mice that can be used to generate antibody or antibody-like molecules as therapeutics.

Regulatory T Cell-Derived TRAIL Is Not Required for Peripheral Tolerance.

TRAIL (Tnfsf10/TRAIL/CD253/Apo2L) is an important immune molecule that mediates apoptosis. TRAIL can play key roles in regulating cell death in the tumor and autoimmune microenvironments. However, dissecting TRAIL function remains difficult because of the lack of optimal models. We have now generated a conditional knockout (Tnfsf10L/L) for cell type–specific analysis of TRAIL function on C57BL/6, BALB/c, and NOD backgrounds. Previous studies have suggested a role for TRAIL in regulatory T cell (Treg)–mediated suppression. We generated mice with a Treg-restricted Tnfsf10 deletion and surprisingly found no impact on tumor growth in C57BL/6 and BALB/c tumor models. Furthermore, we found no difference in the suppressive capacity of Tnfsf10-deficient Tregs and no change in function or proliferation of T cells in tumors. We also assessed the role of TRAIL on Tregs in two autoimmune mouse models: the NOD mouse model of autoimmune diabetes and the myelin oligodendrocyte glycoprotein (MOG) C57BL/6 model of experimental autoimmune encephalomyelitis. We found that deletion of Tnfsf10 on Tregs had no effect on disease progression in either model. We conclude that Tregs do not appear to be dependent on TRAIL exclusively as a mechanism of suppression in both the tumor and autoimmune microenvironments, although it remains possible that TRAIL may contribute in combination with other mechanisms and/or in different disease settings. Our Tnfsf10 conditional knockout mouse should prove to be a useful tool for the dissection of TRAIL function on different cell populations in multiple mouse models of human disease.

GPX4-Regulated Ferroptosis Mediates S100-Induced Experimental Autoimmune Hepatitis Associated with the Nrf2/HO-1 Signaling Pathway.

Autoimmune hepatitis (AIH) is an inflammatory autoimmune disease of the liver. Oxidative stress triggered by reactive oxygen radicals is a common pathophysiological basis for the pathogenesis of many liver diseases, and ferroptosis is associated with the toxic accumulation of reactive oxygen species. The signaling transduction pathways responsible for iron processing and lipid-peroxidation mechanisms are believed to drive ferroptosis. However, the specific mechanisms regulating ferroptosis remain unclear. The aims of this investigation were to identify the possible effector functions of ferroptosis, based on glutathione peroxidase 4 (GPX4) regulation in an S100-induced autoimmune hepatitis mouse model and hepatocyte injury models. The S100 liver antigen-induced AIH mouse model was used to detect ferroptotic biomarkers using western blotting. Upregulated levels of cyclooxygenase2 (COX2) and Acyl-Coenzyme A synthase long-chain family member 4 (ACSL4) were observed in the S100-induced AIH model group, while levels of GPX4 and ferritin heavy chain 1 (FTH1) were downregulated (P < 0.05). The expression profiles of COX2, ACSL4, GPX4, and FTH1 were restored following the administration of ferrostatin-1. In addition, Nrf2 and HO-1 levels in the S100-induced AIH model mice after treatment with ferrostatin-1 were downregulated compared to the nonferrostatin-1-treated S100-induced AIH model mice (P < 0.05). Moreover, COX2 and ACSL4 levels were significantly upregulated, with significant FTH1 downregulation, in the AIH model mice when liver-specific GPX4 was silenced using AAV8 constructs. These data indicate that inhibition of ferroptosis significantly ameliorated the influence of AIH on the Nuclear factor E2-related factor 2 (Nrf2)/Heme oxygenase-1 (HO-1) signaling pathway, and that ferroptosis may act as an initiator or intermediate mediator leading to AIH.

Effects of aspirin, vitamin D3, and progesterone on pregnancy outcomes in an autoimmune recurrent spontaneous abortion model.

High proportions of placental lymphocytes expressing DX5+/CD25+/FOXP3+/CD45+/CD4+ are beneficial to maintain immune tolerance and improve pregnancy outcomes. This study aimed to compare and evaluate the therapeutic effects of aspirin, vitamin D3 (VitD3), and progesterone on the autoimmune recurrent spontaneous abortion (RSA) model. The autoimmune RSA mouse model was constructed, and the embryo loss rate was calculated for each group. Then, primary mouse placental lymphocytes were isolated, and the expression of DX5+/CD25+/FOXP3+/CD45+/CD4+ was detected through flow cytometry. The serum levels of anti-cardiolipin antibody (ACA), β2-GP1, CXCL6, IFN-γ, and IL-6 were measured by ELISA to evaluate the proportion of Th1 and Th2 cells. Autoimmune RSA significantly increased the embryo loss rate, which was improved by aspirin, VitD3, and progesterone treatment, and progesterone treatment had the best effect among the three treatments. The positive expression of DX5+/CD25+/FOXP3+/CD45+/CD4+ in the VitD3 and progesterone groups was significantly higher than that in the autoimmune RSA group, and the expression was highest in the progesterone treatment group. In the plasma of autoimmune RSA mice, the ACA, β2-GP1, CXCL6, and IFN-γ levels were significantly higher and the IL-6 level was lower than the levels in control mice. All these changes could be reversed by aspirin and progesterone treatment. In conclusion, aspirin, VitD3 and progesterone treatment improved pregnancy outcomes in autoimmune RSA mice by regulating the Th1/Th2 balance and cytokines, and progesterone had the best effect of the three treatments.

IL-17A/F enable cholangiocytes to restrict T cell-driven experimental cholangitis by upregulating PD-L1 expression

IL-17A-producing T cells are present in autoimmune cholestatic liver diseases; however, little is known about the contribution of IL-17 to periductal immune responses. Herein, we investigated the role of IL-17 produced by antigen-specific CD8+ T cells in a mouse model of cholangitis and invitro in human cholangiocyte organoids. K14-OVAp mice express a major histocompatibility complex I-restricted ovalbumin (OVA) peptide sequence (SIINFEKL) on cholangiocytes. Cholangitis was induced by the adoptive transfer of transgenic OVA-specific ovalbumin transgene (OT)-1 CD8+ T cells that either had OT-1wt or lacked IL-17A/F (OT-1IL17ko). The response of mouse and human cholangiocytes/organoids to IL-17A was assessed invitro. Transfer of OVA-specific OT-1IL17ko cells significantly aggravated periductal inflammation in K14-OVAp recipient mice compared with transfer of OT-1wt T cells. OT-1IL17ko T cells were highly activated in the liver and displayed increased cytotoxicity and proliferation. IL-17A/F produced by transferred OT-1wt CD8+ T cells induced upregulation of the inhibitory molecule programmed cell death ligand 1 (PD-L1) on cholangiocytes, restricting cholangitis by limiting cytotoxicity and proliferation of transferred cells. In contrast, OT-1IL17ko T cells failed to induce PD-L1 on cholangiocytes, resulting in uncontrolled expansion of cytotoxic CD8+ T cells and aggravated cholangitis. Blockade of PD-L1 after transfer of OT-1wt T cells with anti-PD-L1 antibody also resulted in aggravated cholangitis. Using human cholangiocyte organoids, we were able to confirm that IL-17A induces PD-L1 expression in cholangiocytes. We demonstrate that by upregulating PD-L1 on cholangiocytes, IL-17 has an important role in restricting cholangitis and protecting against CD8+ T cell-mediated inflammatory bile duct injury. Caution should be exercised when targeting IL-17 for the treatment of cholangitis. IL-17 is assumed to be a driver of inflammation in several autoimmune diseases, such as psoriasis. IL-17 is also present in inflammatory diseases of the bile duct, but its role in these conditions is not clear, as the effects of IL-17 depend on the context of its expression. Herein, we investigated the role of IL-17 in an experimental autoimmune cholangitis mouse model, and we identified an important protective effect of IL-17 on cholangiocytes, enabling them to downregulate bile duct inflammation via checkpoint inhibitor PD-L1.

Loss of the Extracellular Matrix Molecule Tenascin-C Leads to Absence of Reactive Gliosis and Promotes Anti-inflammatory Cytokine Expression in an Autoimmune Glaucoma Mouse Model.

Previous studies demonstrated that retinal damage correlates with a massive remodeling of extracellular matrix (ECM) molecules and reactive gliosis. However, the functional significance of the ECM in retinal neurodegeneration is still unknown. In the present study, we used an intraocular pressure (IOP) independent experimental autoimmune glaucoma (EAG) mouse model to examine the role of the ECM glycoprotein tenascin-C (Tnc). Wild type (WT ONA) and Tnc knockout (KO ONA) mice were immunized with an optic nerve antigen (ONA) homogenate and control groups (CO) obtained sodium chloride (WT CO, KO CO). IOP was measured weekly and electroretinographies were recorded at the end of the study. Ten weeks after immunization, we analyzed retinal ganglion cells (RGCs), glial cells, and the expression of different cytokines in retina and optic nerve tissue in all four groups. IOP and retinal function were comparable in all groups. Although RGC loss was less severe in KO ONA, WT as well as KO mice displayed a significant cell loss after immunization. Compared to KO ONA, less βIII-tubulin+ axons, and downregulated oligodendrocyte markers were noted in WT ONA optic nerves. In retina and optic nerve, we found an enhanced GFAP+ staining area of astrocytes in immunized WT. A significantly higher number of retinal Iba1+ microglia was found in WT ONA, while a lower number of Iba1+ cells was observed in KO ONA. Furthermore, an increased expression of the glial markers Gfap, Iba1, Nos2, and Cd68 was detected in retinal and optic nerve tissue of WT ONA, whereas comparable levels were observed in KO ONA. In addition, pro-inflammatory Tnfa expression was upregulated in WT ONA, but downregulated in KO ONA. Vice versa, a significantly increased anti-inflammatory Tgfb1 expression was measured in KO ONA animals. We conclude that Tnc plays an important role in glial and inflammatory response during retinal neurodegeneration. Our results provide evidence that Tnc is involved in glaucomatous damage by regulating retinal glial activation and cytokine release. Thus, this transgenic EAG mouse model for the first time offers the possibility to investigate IOP-independent glaucomatous damage in direct relation to ECM remodeling.

Complement activation in human autoimmune diseases and mouse models; employing a sandwich immunoassay specific for C3dg

In human autoimmune diseases, low plasma levels of complement factors C3 and C4 are commonly used as a proxy for complement activation. The measurements of C3 and C4 concentrations (the result of synthesis and consumption) however, show low sensitivity in patient follow-up. We find that the estimation of the C3dg fragment released during complement activation is a better parameter for complement activation. Available techniques for measuring the activation fragment C3dg, e.g. immune-electrophoresis or involving PEG-precipitation, are time-consuming and difficult to standardize. Here we examine the specificity and use of an antibody with mono-specificity for a neoepitope at the N-terminus of C3dg, which is only exposed after cleavage of C3. We present a stable, reproducible, and easy-to-use, time-resolved immunoassay with specificity for C3dg that can be used to directly evaluate ongoing complement activation. We demonstrate that the assay can be applied to clinicalsamples with a high specificity (95%) and a positive likelihood ratio of 10. It can also differentiate the complement related disease Systemic Lupus Erythematosus from controls and other immune-mediatedimmune mediated diseases like Rheumatoid Arthritis (86% specificity) and Spondyloarthritis (91% specificity). Further, we establish how the assay may also be used for experimental research in in vivo mouse models.

Mitochondrial Oxidative Damage Underlies Regulatory T Cell Defects in Autoimmunity

Regulatory Tcells (Tregs) are vital for the maintenance of immune homeostasis, while their dysfunction constitutes a cardinal feature of autoimmunity. Under steady-state conditions, mitochondrial metabolism is critical for Treg function; however, the metabolic adaptations of Tregs during autoimmunity are ill-defined. Herein, we report that elevated mitochondrial oxidative stress and a robust DNA damage response (DDR) associated with cell death occur in Tregs in individuals with autoimmunity. In an experimental autoimmune encephalitis (EAE) mouse model of autoimmunity, we found a Treg dysfunction recapitulating the features of autoimmune Tregs with a prominent mtROS signature. Scavenging of mtROS in Tregs of EAE mice reversed the DDR and prevented Treg death, while attenuating the Th1 and Th17 autoimmune responses. These findings highlight an unrecognized role of mitochondrial oxidative stress in defining Treg fate during autoimmunity, which may facilitate the design of novel immunotherapies for diseases with disturbed immune tolerance.

TLR7 Negatively Regulates B10 Cells Predominantly in an IFNγ Signaling Dependent Manner

IL-10 producing B cells (B10 cells) play an important immunoregulatory role in various autoimmune and infection conditions. However, the factors that regulate their development and maintenance are incompletely understood. Recently, we and others have established a requirement for TLR7 in promoting autoimmune antibody forming cell (AFC) and germinal center (GC) responses. Here we report an important additional role of TLR7 in the negative regulation of B10 cell development. TLR7 overexpression or overstimulation promoted the reduction of B10 cells whereas TLR7 deficiency rescued these cells in both non-autoimmune and autoimmune-prone mice. TLR7 expression was further inversely correlated with B cell-dependent IL-10 production and its inhibition of CD4 T cell proliferation and IFNγ production in an in vitro B cell and T cell co-culture system. Further, B10 cells displayed elevated TLR7, IFNγR, and STAT1 expression compared to non-B10 cells. Interestingly, deficiency of IFNγR in TLR7 overexpressing lupus-prone mice rescued B10 cells from TLR7-mediated reduction. Finally, B cell intrinsic deletion of IFNγR was sufficient to restore B10 cells in the spleens of TLR7-promoted autoimmune mouse model. In conclusion, our findings demonstrate a novel role for the IFNγR-STAT1 pathway in TLR7-mediated negative regulation of B10 cell development.

Regulation of autoimmune arthritis by the SHP-1 tyrosine phosphatase

BackgroundThe Src homology region 2 domain-containing phosphatase-1 (SHP-1) is known to exert negative regulatory effects on immune cell signaling. Mice with mutations in the Shp1 gene develop inflammatory skin disease and autoimmunity, but no arthritis.We sought to explore the role of SHP-1 in arthritis using an autoimmune mouse model of rheumatoid arthritis. We generated Shp1 transgenic (Shp1-Tg) mice to study the impact of SHP-1 overexpression on arthritis susceptibility and adaptive immune responses.MethodsSHP-1 gene and protein expression as well as tyrosine phosphatase activity were evaluated in spleen cells of transgenic and wild type (WT) mice. WT and Shp1-Tg (homozygous or heterozygous for the transgene) mice were immunized with human cartilage proteoglycan (PG) in adjuvant, and arthritis symptoms were monitored. Protein tyrosine phosphorylation level, net cytokine secretion, and serum anti-human PG antibody titers were measured in immune cells from WT and Shp1-Tg mice. WT mice were treated with regorafenib orally to activate SHP-1 either before PG-induced arthritis (PGIA) symptoms developed (preventive treatment) or starting at an early stage of disease (therapeutic treatment). Data were statistically analyzed and graphs created using GraphPad Prism 8.0.2 software.ResultsSHP-1 expression and tyrosine phosphatase activity were elevated in both transgenic lines compared to WT mice. While all WT mice developed arthritis after immunization, none of the homozygous Shp1-Tg mice developed the disease. Heterozygous transgenic mice, which showed intermediate PGIA incidence, were selected for further investigation. We observed differences in interleukin-4 and interleukin-10 production in vitro, but serum anti-PG antibody levels were not different between the genotypes. We also found decreased tyrosine phosphorylation of several proteins of the JAK/STAT pathway in T cells from PG-immunized Shp1-Tg mice. Regorafenib administration to WT mice prevented the development of severe PGIA or reduced disease severity when started after disease onset.ConclusionsResistance to arthritis in the presence of SHP-1 overexpression likely results from the impairment of tyrosine phosphorylation (deactivation) of key immune cell signaling proteins in the JAK/STAT pathway, due to the overwhelming tyrosine phosphatase activity of the enzyme in Shp1-Tg mice. Our study is the first to investigate the role of SHP-1 in autoimmune arthritis using animals overexpressing this phosphatase. Pharmacological activation of SHP-1 might be considered as a new approach to the treatment of autoimmune arthritis.

Celastrol ameliorates autoimmune disorders in Trex1-deficient mice

Celastrol is one of most potent bioactive molecule isolated from the medicinal plant Tripterygium wilfordii (Thunder God Vine) and is well known for its potential therapeutic value against various chronic diseases including the autoimmune diseases, such as systemic lupus erythematosus and Aicardi-Goutieres syndrome, or other interferonopathies. However, the underlying mechanism of celastrol function remains unclear. Here we showed that celastrol caused inhibition of interferon regulatory factor 3 (IRF3) activation leading to the down-regulation of the interferon response triggered by cytosolic nucleic acids in vitro and in vivo. Moreover, celastrol treatment markedly ameliorates the autoimmune phenotypes including myocarditis, aberrant interferon response and autoantibody production, as well as the excessive T-cell activation in Trex1−/− autoimmune disease mouse model. Collectively, our results indicate that celastrol inhibits interferon response by targeting IRF3 activation and may be used as an effective treatment for interferon response-dependent autoimmune diseases.

Expansion of polyreactive and autoreactive IgG B cells in NOD.H-2h4 mice, a model of Sjögren’s Syndrome

Abstract In genetically prone individuals, chronic immune activation may lead to expansion of autoreactive lymphocyte clones that can induce organ damage developing autoimmune disorders. Sjögren’s Syndrome (SjS) is one of the most common systemic chronic autoimmune diseases that primarily affects exocrine glands with progressive dryness of mouth and eyes. Despite the accumulated evidences of profound B-cell alterations of humoral immunity, the repertoire and onset of B-cell autoreactivity in SjS remains to be determined. We hypothesize that SjS mice will have an increased frequency of self-reactive B cells with a progressive evolution to antigen-driven oligoclonality. Here, we study the B cell repertoire of NOD.H-2h4 mice, a mouse model of spontaneous autoimmunity mimicking SjS without developing diabetes. All female mice presented salivary gland infiltrates and autoantibodies such as anti-dsDNA and anti-Ro52, both characteristic of SjS, at the age of 24 weeks. A library of 456 hybridomas from NOD.H-2h4 mice splenocytes at three different ages: 28, 47 and 66 weeks old was created. The presence of mono or polyreactive autoantibodies against dsDNA, Ro52, LPS, insulin, histones and OVA was evaluated by ELISA, and their staining patterns and cellular reactivity were tested by IFA and FACS. We observed a high percentage of autoreactivity among B-cell clones from NOD.H-2h4 mice. IgM autoreactive B cells were maintained, while polyreactive and autoreactive IgG clones increased with mice age. Interestingly, all anti-Ro52 autoantibodies were polyreactive. Our results indicate that in the NOD.H-2h4 mouse model of SjS, IgG+ B cells are mainly polyreactive and might expand following an unknown antigen-driven positive selection process.

IL-37 increases liver inflammation in Con A-induced hepatitis by increasing IFN-γ secretion of infiltrated NK Cells

Abstract Liver is an immunologically tolerogenic organ, while, autoreactive immune cells mediated autoimmune hepatitis (AIH) is observed. Suppression of the hyper-reactive immune responses may restore the tolerance of liver. IL-37, an emerging IL-1 family cytokine with anti-inflammatory effects on innate and adaptive immunity, shows benefit on many autoimmune diseases. We proposed IL-37 could inhibit immune responses and improve AIH. IL-37 expressing adeno-associated virus (AAV-IL-37) successfully dampened the activation of macrophages in vitro. We next analyzed the effect of IL-37 in Con A-induced autoimmune hepatitis mouse model. Surprisingly, the liver histopathology showed more necrotic hepatocytes and infiltrating immune cells in AAV-IL-37 treated Con A mice than in control mice. Higher levels of serum IFN-γ in IL-37-expressing Con A mice were observed. Moreover, expression of inflammation-related mRNA in the liver were also highly induced with AAV-IL-37 treatment. Among hepatic lymphoid cells, NK and NKT cells were particularly increased in IL-37 treated Con A mice. The frequency of IFN-γ-secreting NK cells was also significantly increased. Further, CCL5, a chemoattractant for NK cells, was significantly elevated in the serum of AAV-IL-37 injected Con A mice. These results suggest that IL-37 worsen liver inflammation instead of relieving the disease. Of note, there was no obvious inflammation in AAV-IL-37 treated naïve mice, suggesting the proinflammatory effect of IL-37 in Con A treated mice resulted from the inflamed liver microenvironment. In conclusion, IL-37 aggravated liver inflammation in Con A induced hepatitis through recruiting NK cells and elevating the IFN-γ secretion of NK cells.

Treating Autoimmune Diseases by Targeting IL-23 with Gene-Silencing Pyrrole-Imidazole Polyamide.

Autoimmune diseases are a physiological state that immune responses are directed against and damage the body's own tissues. Numerous studies have demonstrated promising therapeutic effects in certain autoimmune diseases by targeting IL-23/IL-17 axis, mostly through using Abs against IL-23 or IL-17A. Pyrrole-imidazole polyamides are nuclease-resistant compounds that inhibit gene expression through binding to the minor groove of DNA. To develop a novel gene-silencing agent that targets IL-23/IL-17 axis, we designed polyamide that specifically binds to the transcription factor c-Rel-binding site located in the promoter of IL-23p19 subunit. Our study showed that this polyamide is capable of entering into nucleus with high efficiency in dendritic cells and macrophage. In addition, it prevented the binding of c-Rel to the promoter of IL-23p19 in vivo and specifically inhibited the expression of IL-23. More importantly, we demonstrated that this polyamide is therapeutically effective using both the imiquimod-induced psoriasis and experimental autoimmune uveitis mouse models. Taken together, these results indicate that pyrrole-imidazole polyamide targeting IL-23p19 could be a novel and feasible therapeutic strategy for patients with autoimmune diseases.

MiR-21 and Pellino-1 Expression Profiling in Autoimmune Premature Ovarian Insufficiency.

Background Premature ovarian insufficiency (POI) represents the hypergonadotropic hypoestrogenic symptoms that result in the loss of ovarian follicles. 5-30% POI cases are suggested to be involved in autoimmune etiology. MicroRNA-21 (miR-21) plays a vital role in ovarian folliculogenesis via regulating and interacting with multiple target genes. Here, we conduct the target prediction of miR-21, identify the expression and correlation of miR-21 and its putative target Pellino-1 (Peli1), and confirm their relationship with clinical characteristics in autoimmune POI. Methods Bioinformatic analysis was conducted to screen the miR-21 putative target gene. Autoimmune POI mouse models were established by ZP3 immunization. Serum miR-21, Peli1 mRNA of peripheral blood mononuclear cells (PBMCs) and regulatory T cells (Tregs), general status, spleen Tregs ratio, inflammatory factors, ovarian endocrine function, and ovarian structure were evaluated. For autoimmune POI patients, serum miR-21, PBMCs Peli1 mRNA levels, general data, immune parameters, hormone levels, and ultrasound examinations were obtained. The correlations of miR-21 with Peli1 and clinical characteristics in patients were analyzed. Results Peli1 was selected based on four microRNA prediction databases and literature retrieval. In mouse models, serum miR-21 level, PBMCs and Tregs Peli1 mRNA, and spleen Tregs ratio were 0.61 ± 0.09, 0.12 ± 0.12, 0.27±0.23 and 4.82 ± 0.58, respectively, lower than those in the control group. In patients, miR-21 level (0.60 ± 0.14) and Peli1 mRNA (0.30 ± 0.14) were lower than those in the control group (1.01 ± 0.07 and 1.63 ± 0.54); miR-21 was positively related with Peli1, AMH, E2, the size of the uterus, and ovarian volume and negatively related with FSH, LH, and the number of positive immune parameters (AOAb, EMAb, ACL, ANA, ds-DNA, ACA, IgG, IgA, IgM, IgE, C3, and C4). Conclusions Low expressions of miR-21 and Peli1 were detected in autoimmune POI mice and patients. Positive correlation between miR-21 and Peli1 was observed in autoimmune POI patients, suggesting that miR-21 and Peli1 might be associated with the pathogenesis of autoimmune POI.

Roles of Endogenous IL-10 and IL-10-Competent and CD5+ B Cells in Autoimmune Thyroiditis in NOD.H-2h4 Mice.

Interleukin (IL)-10 is a highly important anti-inflammatory cytokine in the immune system. CD1dhi and CD5+ B cells are both traditionally defined IL-10-secreting B cells. In recent years, a B cell group with combined markers of CD1dhi and CD5+ has been widely studied as it has been reported to suppress autoimmunity in mouse models of autoimmune diseases through IL-10 mechanisms. From the perspective of origination, CD1dhi and CD5+ B cells are developed from different B cell lineages. Whether the regulatory capacity of these 2 B cell groups is consistent with their ability to secrete IL-10 has not been determined. In this study, we generated IL-10 knockout NOD.H-2h4 mice to investigate the function of endogenous IL-10 in autoimmune thyroiditis and conducted adoptive transfer experiments to explore the respective roles of CD5+ and CD1dhi B cells. In our results, the IL-10-/- NOD.H-2h4 mice developed thyroiditis, similar to wild-type NOD.H-2h4 mice. The CD5+ B cells were more capable of secreting IL-10 than CD1dhi B cells in flow cytometric analysis, but the CD1dhi B cells showed more suppressive effects on thyroiditis development and autoantibody production, as well as Th17 cell response. In conclusion, endogenous IL-10 does not play an important role in autoimmune thyroiditis. CD1dhi B cells may play regulatory roles through mechanisms other than secreting IL-10.

Mitochondrial Oxidative Phosphorylation Regulates the Fate Decision between Pathogenic Th17 and Regulatory T Cells

SUMMARYUnderstanding metabolic pathways that regulate Th17 development is important to broaden therapeutic options for Th17-mediated autoimmunity. Here, we report a pivotal role of mitochondrial oxidative phosphorylation (OXPHOS) for lineage specification toward pathogenic Th17 differentiation. Th17 cells rapidly increase mitochondrial respiration during development, and this is necessary for metabolic reprogramming following T cell activation. Surprisingly, specific inhibition of mitochondrial ATP synthase ablates Th17 pathogenicity in a mouse model of autoimmunity by preventing Th17 pathogenic signature gene expression. Notably, cells activated under OXPHOS-inhibited Th17 conditions preferentially express Foxp3, rather than Th17 genes, and become suppressive Treg cells. Mechanistically, OXPHOS promotes the Th17 pioneer transcription factor, BATF, and facilitates T cell receptor (TCR) and mTOR signaling. Correspondingly, overexpression of BATF rescues Th17 development when ATP synthase activity is restricted. Together, our data reveal a regulatory role of mitochondrial OXPHOS in dictating the fate decision between Th17 and Treg cells by supporting early molecular events necessary for Th17 commitment.