Experimental Autoimmune Encephalomyelitis Model Research Articles

Interferon-gamma ameliorates experimental autoimmune encephalomyelitis by inducing homeostatic adaptation of microglia.

Compelling evidence has shown that interferon (IFN)-γ has dual effects in multiple sclerosis and in its animal model of experimental autoimmune encephalomyelitis (EAE), with results supporting both a pathogenic and beneficial function. However, the mechanisms whereby IFN-γ may promote neuroprotection in EAE and its effects on central nervous system (CNS)-resident cells have remained an enigma for more than 30 years. In this study, the impact of IFN-γ at the peak of EAE, its effects on CNS infiltrating myeloid cells (MC) and microglia (MG), and the underlying cellular and molecular mechanisms were investigated. IFN-γ administration resulted in disease amelioration and attenuation of neuroinflammation associated with significantly lower frequencies of CNS CD11b+ myeloid cells and less infiltration of inflammatory cells and demyelination. A significant reduction in activated MG and enhanced resting MG was determined by flow cytometry and immunohistrochemistry. Primary MC/MG cultures obtained from the spinal cord of IFN-γ-treated EAE mice that were ex vivo re-stimulated with a low dose (1 ng/ml) of IFN-γ and neuroantigen, promoted a significantly higher induction of CD4+ regulatory T (Treg) cells associated with increased transforming growth factor (TGF)-β secretion. Additionally, IFN-γ-treated primary MC/MG cultures produced significantly lower nitrite in response to LPS challenge than control MC/MG. IFN-γ-treated EAE mice had a significantly higher frequency of CX3CR1high MC/MG and expressed lower levels of program death ligand 1 (PD-L1) than PBS-treated mice. Most CX3CR1highPD-L1lowCD11b+Ly6G- cells expressed MG markers (Tmem119, Sall2, and P2ry12), indicating that they represented an enriched MG subset (CX3CR1highPD-L1low MG). Amelioration of clinical symptoms and induction of CX3CR1highPD-L1low MG by IFN-γ were dependent on STAT-1. RNA-seq analyses revealed that in vivo treatment with IFN-γ promoted the induction of homeostatic CX3CR1highPD-L1low MG, upregulating the expression of genes associated with tolerogenic and anti-inflammatory roles and down-regulating pro-inflammatory genes. These analyses highlight the master role that IFN-γ plays in regulating microglial activity and provide new insights into the cellular and molecular mechanisms involved in the therapeutic activity of IFN-γ in EAE.

GPR43 stimulation on TCRαβ+ intraepithelial colonic lymphocytes inhibits the recruitment of encephalitogenic T-cells into the central nervous system and attenuates the development of autoimmunity

IntroductionGut microbiota plays a critical role in the regulation of immune homeostasis. Accordingly, several autoimmune disorders have been associated with dysbiosis in the gut microbiota. Notably, the dysbiosis associated with central nervous system (CNS) autoimmunity involves a substantial reduction of bacteria belonging to Clostridia clusters IV and XIVa, which constitute major producers of short-chain fatty acids (SCFAs). Here we addressed the role of the surface receptor-mediated effects of SCFAs on mucosal T-cells in the development of CNS autoimmunity.MethodsTo induce CNS autoimmunity, we used the mouse model of experimental autoimmune encephalomyelitis (EAE) induced by immunization with the myelin oligodendrocyte glycoprotein (MOG)-derived peptide (MOG35-55 peptide). To address the effects of GPR43 stimulation on colonic TCRαβ+ T-cells upon CNS autoimmunity, mucosal lymphocytes were isolated and stimulated with a selective GPR43 agonist ex vivo and then transferred into congenic mice undergoing EAE. Several subsets of lymphocytes infiltrating the CNS or those present in the gut epithelium and gut lamina propria were analysed by flow cytometry. In vitro migration assays were conducted with mucosal T-cells using transwells.ResultsOur results show a sharp and selective reduction of intestinal propionate at the peak of EAE development, accompanied by increased IFN-γ and decreased IL-22 in the colonic mucosa. Further analyses indicated that GPR43 was the primary SCFAs receptor expressed on T-cells, which was downregulated on colonic TCRαβ+ T-cells upon CNS autoimmunity. The pharmacologic stimulation of GPR43 increased the anti-inflammatory function and reduced the pro-inflammatory features in several TCRαβ+ T-cell subsets in the colonic mucosa upon EAE development. Furthermore, GPR43 stimulation induced the arrest of CNS-autoreactive T-cells in the colonic lamina propria, thus avoiding their infiltration into the CNS and dampening the disease development. Mechanistic analyses revealed that GPR43-stimulation on mucosal TCRαβ+ T-cells inhibits their CXCR3-mediated migration towards CXCL11, which is released from the CNS upon neuroinflammation.ConclusionsThese findings provide a novel mechanism involved in the gut-brain axis by which bacterial-derived products secreted in the gut mucosa might control the CNS tropism of autoreactive T-cells. Moreover, this study shows GPR43 expressed on T-cells as a promising therapeutic target for CNS autoimmunity.

STA-21, a small molecule STAT3 inhibitor, ameliorates experimental autoimmune encephalomyelitis by altering Th-17/Treg balance.

Numerous studies have demonstrated the role of T helper (Th) 17 and T regulatory (reg) cells and pro-inflammatory and anti-inflammatory cytokines related to these cells in the pathogenesis of MS and its animal model, experimental autoimmune encephalomyelitis (EAE). STAT3 is one of the downstream signaling proteins of IL-23, IL-6, and IL-21 that are required for Th17 cells differentiation. STA-21 is a STAT3 inhibitor that functions by inhibiting STAT3 dimerization and binding to DNA impairing the expression of STAT3 target genes including, RORγt, IL-21 and IL-23R that are also required for Th17 cell differentiation. In this study, we evaluated the effect of STA-21 on EAE Model and investigated how this small molecule can change Th17/Treg balance leading to amelioration of disease. After EAE induction and treatment with STA-21, its effects were assessed. Major assays were H&E and LFB staining, Flow cytometric analysis, Reverse transcription-PCR (RT-PCR), and ELISA. STA-21 ameliorated the EAE severity and decreased the EAE inflammation and demyelination. It also decreased STAT3 phosphorylation, the proportion of Th17 cells and the protein level of IL-17. In contrast, the balance of Tregs and the level of anti-inflammatory cytokine, IL-10 increased in STA-21-treated mice. Moreover, STA-21 significantly decreased the expression of Th17 related transcription factors, RORɣt and IL-23R while FOXP3 expression associated with Treg differentiation was increased. This study showed that STA-21 has therapeutic effects in EAE by reducing inflammation and shifting inflammatory immune responses to anti-inflammatory and can be used as a suitable treatment strategy for the treatment of EAE. The effectiveness of inhibiting or strengthening the functional cells of the immune system by these small molecules in terms of easy to access, simple construction and inexpensive expansion make them as a suitable tool for the treatment of inflammatory and autoimmune diseases.

TNF-α/STAT1/CXCL10 mutual inflammatory axis that contributes to the pathogenesis of experimental models of multiple sclerosis: A promising signaling pathway for targeted therapies

BackgroundIdentifying mutual neuroinflammatory axis in different experimental models of multiple sclerosis (MS) is essential to evaluate the de- and re-myelination processes and improve therapeutic interventions' reproducibility. MethodsThe expression profile data set of EAE (GSE47900) and cuprizone (GSE100663) models were downloaded from the Gene Expression Omnibus database. The R package and GEO2R software processed these raw chip data. Gene Ontology (GO) functional analysis, KEGG pathway analysis, and protein–protein interaction network analysis were performed to investigate interactions between common differentially expressed genes (DEGs) in all models. Finally, the ELISA method assessed the protein level of highlighted mutual cytokines in serum. Results: Our data introduced 59 upregulated [CXCL10, CCL12, and GBP6 as most important] and 17 downregulated [Serpinb1a, Prr18, and Ugt8a as most important] mutual genes. The signal transducer and activator of transcription 1 (STAT1) and CXCL10 were the most crucial hub proteins among mutual upregulated genes. These mutual genes were found to be mainly involved in the TNF-α, TLRs, and complement cascade signaling, and animal models shared 26 mutual genes with MS individuals. Finally, significant upregulation of serum level of TNF-α/IL-1β/CXCL10 cytokines was confirmed in all models in a relatively similar pattern. ConclusionFor the first time, our study revealed the common neuroinflammatory pathway in animal models of MS and introduced candidate hub genes for better evaluating the preclinical efficacy of pharmacological interventions and designing prospective targeted therapies.

The Anti-inflammatory Effect of Ginger Extract on the Animal Model of Multiple Sclerosis.

Experimental autoimmune encephalomyelitis (EAE), as an autoimmune disease in the central nervous system (CNS), is an animal model for multiple sclerosis (MS) mediated by T lymphocytes. To investigate ginger extract's effect on reducing inflammation and improving the symptoms in the EAE model. The EAE was induced by injecting MOG35-55 and pertussis toxin into eight-week-old female C57BL6 mice. The mice were treated with an intraperitoneal injection of 300 mg/kg/day of hydroalcoholic extract of ginger for 21 days. The disease severity and weight changes were measured daily. Then, the mice spleens were removed; the gene expressions of interleukin (IL)-17, transforming growth factor beta (TGF-β), interferon-γ (IFN-γ), and tumor necrosis factor α (TNF-α) were analyzed by Real-time PCR and the percentage of regulatory T lymphocytes (Treg cells) was determined by flow cytometry. Serum nitric oxide and antioxidant capacity were measured, and brain tissue sections were prepared to investigate the leukocyte infiltration and plaque formation. The severity of symptoms in the intervention group was lower than in the control. The gene expression levels of inflammatory cytokines, including IL-17 (P=0.04) and IFN-γ (P=0.01), were reduced. The Treg cells increased significantly, and the serum nitric oxide level was lower in the ginger-treated group. There was no significant difference in lymphocyte infiltration in the brain between the two groups. The present study indicated that ginger extract could effectively reduce inflammatory mediators and modulate immune responses in EAE.

Constitutive IL-1RA production by modified immune cells protects against IL-1-mediated inflammatory disorders.

Dysregulation of the interleukin-1 (IL-1) pathway leads to immune diseases that can result in chronic tissue and organ inflammation. Although IL-1 blockade has shown promise in ameliorating these symptoms and improving patients' quality of life, there is an urgent need for more effective, long-lasting treatments. We developed a lentivirus (LV)-mediated gene transfer strategy using transplanted autologous hematopoietic stem/progenitor cells (HSPCs) as a source of IL-1 receptor antagonist (IL-1RA) for systemic delivery to tissues and organs. Transplantation of mouse and human HSPCs transduced with an IL-1RA-encoding LV ensured stable IL-1RA production while maintaining the clonogenic and differentiation capacities of HSPCs in vivo. We examined the efficacy of cell-mediated IL-1RA delivery in three models of IL-1-dependent inflammation, for which treatment hindered neutrophil recruitment in an inducible model of gout, prevented systemic and multi-tissue inflammation in a genetic model of cryopyrin-associated periodic syndromes, and reduced disease severity in an experimental autoimmune encephalomyelitis model of multiple sclerosis. Our findings demonstrate HSPC-mediated IL-1RA delivery as a potential therapeutic modality that can be exploited to suppress tissue and organ inflammation in diverse immune-related diseases involving IL-1-driven inflammation.

AXL-Induced Autophagy mitigates experimental autoimmune encephalomyelitis by suppressing microglial inflammation via the PI3K/AKT/mTOR signaling pathway

Microglia, being the primary immune cells of the central nervous system (CNS), are responsible for pathological inflammatory demyelination in multiple sclerosis (MS). It has been demonstrated that AXL, one of the receptor tyrosine kinases, could alleviate the inflammatory response of microglia. However, the specific mechanism remains unclear. Herein, we explored the role of AXL in the autophagy of microglia and its effect on the experimental autoimmune encephalomyelitis (EAE) model. We revealed that knockout of AXL in BV2 microglia significantly promoted the expression of phosphorylated-PI3K/p-AKT/p-mTOR while significantly inhibiting LC3-Ⅱ/Beclin1. Similarly, autophagy was significantly inhibited in the AXL-/- mice. Knockout of AXL induced serious symptoms, infiltration of inflammatory cells, and demyelination changes, manifesting as the upregulation of pro-inflammatory factors TNF-α and IL-6 and downregulation of anti-inflammatory factors TGF-β and IL-10. In conclusion, this study substantiated that autophagy induced by AXL inhibited the inflammatory response of microglia and alleviated symptoms of EAE. Autophagy activation was mediated by the PI3K/AKT/mTOR signaling pathway.

DAPTA, a C-C Chemokine Receptor 5 (CCR5), Leads to the Downregulation of Notch/NF-κB Signaling and Proinflammatory Mediators in CD40+ Cells in Experimental Autoimmune Encephalomyelitis Model in SJL/J Mice.

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system characterized by motor deficits, cognitive impairment, fatigue, pain, and sensory and visual dysfunction. CD40, highly expressed in B cells, plays a significant role in MS pathogenesis. The experimental autoimmune encephalomyelitis (EAE) mouse model of MS has been well established, as well as its relevance in MS patients. This study aimed to evaluate the therapeutic potential of DAPTA, a selective C-C chemokine receptor 5 (CCR5) antagonist in the murine model of MS, and to expand the knowledge of its mechanism of action. Following the induction of EAE, DAPTA was administrated (0.01 mg/kg, i.p.) daily from day 14 to day 42. We investigated the effects of DAPTA on NF-κB p65, IκBα, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α in CD40+ spleen B cells using flow cytometry. Furthermore, we also analyzed the effect of DAPTA on NF-κB p65, IκBα, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α mRNA expression levels using qRT-PCR in brain tissue. EAE mice treated with DAPTA showed substantial reductions in NF-κB p65, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α but an increase in the IκBα of CD40+ B lymphocytes. Moreover, EAE mice treated with DAPTA displayed decreased NF-κB p65, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α and but showed increased IκBα mRNA expression levels. This study showed that DAPTA has significant neuroprotective potential in EAE via the downregulation of inflammatory mediators and NF-κB/Notch signaling. Collectively, DAPTA might have potential therapeutic targets for use in MS treatment.

GM-CSF Promotes the Survival of Peripheral-Derived Myeloid Cells in the Central Nervous System for Pain-Induced Relapse of Neuroinflammation.

We recently discovered a (to our knowledge) new neuroimmune interaction named the gateway reflex, in which the activation of specific neural circuits establishes immune cell gateways at specific vessel sites in organs, leading to the development of tissue-specific autoimmune diseases, including a multiple sclerosis (MS) mouse model, experimental autoimmune encephalomyelitis (EAE). We have reported that peripheral-derived myeloid cells, which are CD11b+MHC class II+ and accumulate in the fifth lumbar (L5) cord during the onset of a transfer model of EAE (tEAE), play a role in the pain-mediated relapse via the pain-gateway reflex. In this study, we investigated how these cells survive during the remission phase to cause the relapse. We show that peripheral-derived myeloid cells accumulated in the L5 cord after tEAE induction and survive more than other immune cells. These myeloid cells, which highly expressed GM-CSFRα with common β chain molecules, grew in number and expressed more Bcl-xL after GM-CSF treatment but decreased in number by blockade of the GM-CSF pathway, which suppressed pain-mediated relapse of neuroinflammation. Therefore, GM-CSF is a survival factor for these cells. Moreover, these cells were colocalized with blood endothelial cells (BECs) around the L5 cord, and BECs expressed a high level of GM-CSF. Thus, GM-CSF from BECs may have an important role in the pain-mediated tEAE relapse caused by peripheral-derived myeloid cells in the CNS. Finally, we found that blockade of the GM-CSF pathway after pain induction suppressed EAE development. Therefore, GM-CSF suppression is a possible therapeutic approach in inflammatory CNS diseases with relapse, such as MS.

212 Co‐delivery of Vitamin D3 and Antigens by Nanoparticles Enhances Immune Tolerance through Induction of Tolerogenic Dendritic Cells in vivo

AbstractTolerogenic dendritic cells (tDCs) induces regulatory T cell (Treg) differentiation and promotes immune tolerance. However, the effective generation of tDCs in vivo to treat autoimmune diseases remains a significant challenge. In this study, the potential of 1α, 25‐Dihydroxyvitamin D3 (VD3) is explored, which has been shown to promote tDCs differentiation in vitro, to induce tDCs in a mouse model of experimental autoimmune encephalomyelitis (EAE). To overcome the poor solubility of VD3 and induce autoantigen‐specific Tregs, a PLGA‐PEG‐based nano‐drug delivery system is prepared to co‐deliver VD3 and myelin‐oligodendrocyte glycoprotein (MOG) peptides. It is found that intradermal (i.d.) injection of NP/VD3/MOG significantly enhanced the level of antigen‐specific Tregs in vivo. Furthermore, NP/VD3/MOG remarkedly delayed the onset, reduced the severity, and promoted the recovery of EAE mice. This study provides an effective strategy for the treatment of autoimmune diseases.

Multiparametric magnetic resonance imagingfor detection of pathological changes in the central nervous system of a mouse model of multiple sclerosis in vivo.

Multiple sclerosis (MS) is an autoimmune disease involving demyelination and axonal damage in the central nervous system (CNS). In this study, we investigated pathological changes in the lumbar spinal cord of C57BL/6 mice induced with progressive experimental autoimmune encephalomyelitis (EAE) disease using 9.4-T magnetic resonance imaging (MRI). Multiparametric MRI measurements including MR spectroscopy, diffusion tensor imaging (DTI) and volumetric analyses were applied to detect metabolic changes in the CNS of EAE mice. Compared with healthy mice, EAE mice showed a significant reduction in N-acetyl aspartate and increases in choline, glycine, taurine and lactate. DTI revealed a significant reduction in fractional anisotropy and axial diffusivity and an increase in radial diffusivity in the lumbar spinal cord white matter (WM), while in the grey matter (GM), fractional anisotropy increased. High-resolution structural imaging also revealed lumbar spinal cord WM hypertrophy and GM atrophy. Importantly, these MRI changes were strongly correlated with EAE disease scoring and pathological changes in the lumbar (L2-L6), particularly WM demyelination lesions and aggregation of immune cells (microglia/macrophages and astrocytes) in this region. This study identified changes in MRI biomarker signatures that can be useful for evaluating the efficacy of novel drugs using EAE models in vivo.

Protein Phosphatase 2A: Role in T Cells and Diseases.

Protein phosphatase 2A (PP2A) is a serine-threonine phosphatase that plays an important role in the regulation of cell proliferation and signal transduction. The catalytic activity of PP2A is integral in the maintenance of physiological functions which gets severely impaired in its absence. PP2A plays an essential role in the activation, differentiation, and functions of T cells. PP2A suppresses Th1 cell differentiation while promoting Th2 cell differentiation. PP2A fosters Th17 cell differentiation which contributes to the pathogenesis of systemic lupus erythematosus (SLE) by enhancing the transactivation of the Il17 gene. Genetic deletion of PP2A in Tregs disrupts Foxp3 expression due to hyperactivation of mTORC1 signaling which impairs the development and immunosuppressive functions of Tregs. PP2A is important in the induction of Th9 cells and promotes their antitumor functions. PP2A activation has shown to reduce neuroinflammation in a mouse model of experimental autoimmune encephalomyelitis (EAE) and is now used to treat multiple sclerosis (MS) clinically. In this review, we will discuss the structure and functions of PP2A in T cell differentiation and diseases and therapeutic applications of PP2A-mediated immunotherapy.

Genetically Engineered Artificial Microvesicles Carrying Nerve Growth Factor Restrains the Progression of Autoimmune Encephalomyelitis in an Experimental Mouse Model.

Multiple sclerosis (MS) is an incurable, progressive chronic autoimmune demyelinating disease. Therapy for MS is based on slowing down the processes of neurodegeneration and suppressing the immune system of patients. MS is accompanied by inflammation, axon-degeneration and neurogliosis in the central nervous system. One of the directions for a new effective treatment for MS is cellular, subcellular, as well as gene therapy. We investigated the therapeutic potential of adipose mesenchymal stem cell (ADMSC) derived, cytochalasin B induced artificial microvesicles (MVs) expressing nerve growth factor (NGF) on a mouse model of multiple sclerosis experimental autoimmune encephalomyelitis (EAE). These ADMSC-MVs-NGF were tested using histological, immunocytochemical and molecular genetic methods after being injected into the tail vein of animals on the 14th and 21st days post EAE induction. ADMSC-MVs-NGF contained the target protein inside the cytoplasm. Their injection into the caudal vein led to a significant decrease in neurogliosis at the 14th and 21st days post EAE induction. Artificial ADMSC-MVs-NGF stimulate axon regeneration and can modulate gliosis in the EAE model.

Acute intermittent hypoxia alters disease course and promotes CNS repair including resolution of inflammation and remyelination in the experimental autoimmune encephalomyelitis model of MS.

Remyelination and neurodegeneration prevention mitigate disability in Multiple Sclerosis (MS). We have shown acute intermittent hypoxia (AIH) is a novel, non-invasive and effective therapy for peripheral nerve repair, including remyelination. Thus, we posited AIH would improve repair following CNS demyelination and address the paucity of MS repair treatments. AIH's capacity to enhance intrinsic repair, functional recovery and alter disease course in the experimental autoimmune encephalomyelitis (EAE) model of MS was assessed. EAE was induced by MOG35-55 immunization in C57BL/6 female mice. EAE mice received either AIH (10 cycles-5 min 11% oxygen alternating with 5 min 21% oxygen) or Normoxia (control; 21% oxygen for same duration) once daily for 7d beginning at near peak EAE disease score of 2.5. Mice were followed post-treatment for an additional 7d before assessing histopathology or 14d to examine maintenance of AIH effects. Alterations in histopathological correlates of multiple repair indices were analyzed quantitatively in focally demyelinated ventral lumbar spinal cord areas to assess AIH impacts. AIH begun at near peak disease significantly improved daily clinical scores/functional recovery and associated histopathology relative to Normoxia controls and the former were maintained for at least 14d post-treatment. AIH enhanced correlates of myelination, axon protection and oligodendrocyte precursor cell recruitment to demyelinated areas. AIH also effected a dramatic reduction in inflammation, while polarizing remaining macrophages/microglia toward a pro-repair state. Collectively, this supports a role for AIH as a novel non-invasive therapy to enhance CNS repair and alter disease course following demyelination and holds promise as a neuroregenerative MS strategy.

Myocardial infarction-induced disruption of blood-brain barrier in hypothalamic paraventricular nucleus is mediated by interleukin-17A signaling in rat

Increased inflammatory cytokines in the circulation act in the brain to promote neuroinflammation and sympathetic excitation in myocardial infarction-induced heart failure (HF). However, the mechanisms by which proinflammatory cytokines interrupt blood-brain barrier (BBB) to reach brain remain unclear. We recently reported that the levels of interleukin (IL)-17A, a key inflammatory mediator of immune responses, are significantly elevated in circulation and the brain in HF. IL-17A has been shown to disrupt the integrity of BBB in in vitro model and in vivo rodent model of experimental autoimmune encephalomyelitis. The present study sought to determine whether BBB in hypothalamic paraventricular nucleus (PVN), a key cardiovascular/autonomic region of the brain within the BBB, was damaged in HF and if so, whether IL-17A contributes to BBB disruption in this disease setting. Adult male Sprague Dawley rats underwent coronary artery ligation to induce HF or sham surgery (Sham). Some HF rats were pretreated with bilateral PVN microinjections of an IL-17 receptor A (IL-17RA) siRNA AAV virus or a scrambled siRNA control. The left ventricular function and infarction size were evaluated by echocardiography. Four weeks after coronary artery ligation, BBB permeability was assessed with fluorescein isothiocyanate (FITC, 10 kDa)-dextran extravasation and molecular measurements of its biomarkers. FITC was injected through left carotid artery at a rate of 300 μl/min (10 mg/ml, 3 ml/kg) and allowed to circulate for 30 min. We found that HF rats displayed noticeable FITC extravasation within the PVN area when compared with brain cortex after injections. FITC extravasation was not observed in the PVN and brain cortex in Sham rats. Compared with Sham rats, HF rats had significantly increased PVN mRNA expression of caveolin-1 (1.05± 0.13 vs 3.30 ± 0.48*, fold changes; *P<0.05), a molecular marker of transcytosis, and decreased PVN mRNA levels of occludin and zonula occludens-1 (1.05± 0.14 vs 0.57 ± 0.13*; 1.05± 0.10 vs 0.54 ± 0.03*, respectively), two important tight junction-associated molecules. However, the mRNA expression of caveolin-1, occludin or zonula occludens-1 did not display significant difference in the brain cortex between HF and Sham rats. Pretreatment with IL-17RA siRNA, substantially reduced FITC extravasation within the PVN and reversed mRNA expression of caveolin-1 (1.08 ± 0.20 vs. 0.51 ± 0.09*), occludin (1.07 ± 0.15 vs. 1.86 ± 0.18*) or zonula occludens-1 (1.02 ± 0.08 vs.1.84 ± 0.24*) in HF rats when compared with HF rats pretreated with a scrambled siRNA control. These data indicated that BBB permeability is increased in the PVN in myocardial infarction-induced HF. The activated IL-17A/IL-17RA signaling in BBB endothelium in the PVN in HF may play an important role in disrupting BBB, probably by a molecular mechanism to augment transcellular transport and reduce tight junction protein expression. Supported by NIH grants R01 HL-139521 & HL-155091 to SGW This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

S3I-201, a selective stat3 inhibitor, ameliorates clinical symptoms in a mouse model of experimental autoimmune encephalomyelitis through the regulation of multiple intracellular signalling in Th1, Th17, and treg cells.

CD4+T cells, specifically Th cells (Th1 and Th17) and regulatory T cells (Tregs), play a pivotal role in the pathogenesis of multiple sclerosis (MS), a demyelinating autoimmune disease of the CNS. STAT3 inhibitors are potential therapeutic targets for several immune disorders. In this study, we investigated the role of a well-known STAT3 inhibitor, S3I-201, in experimental autoimmune encephalomyelitis (EAE), a model of MS. Following induction of EAE, mice were intraperitoneally administered S3I-201 (10 mg/kg) each day, beginning on day 14 and continuing till day 35 and were evaluated for clinical signs. Flow cytometry was used to investigate further the effect of S3I-201 on Th1 (IFN-γ, STAT1, pSTAT1, and T-bet), Th17 (IL-17A, STAT3, pSTAT3, and RORγt), and regulatory T cells (Treg, IL-10, TGF-β1, and FoxP3) expressed in splenic CD4+ T cells. Moreover, we analyzed the effects of S3I-201 on mRNA and protein expression of IFN-γ, T-bet, IL-17A, STAT1, STAT3, pSTAT1, pSTAT3, RORγ, IL-10, TGF-β1, and FoxP3 in the brains of EAE mice. The severity of clinical scores decreased in S3I-201-treated EAE mice compared to vehicle-treated EAE mice. S3I-201 treatment significantly decreased CD4+IFN-γ+, CD4+STAT1+, CD4+pSTAT1+, CD4+T-bet+, CD4+IL-17A+, CD4+STAT3+, CD4+pSTAT3+, and CD4+RORγt+ and increased CD4+IL-10+, CD4+TGF-β1+, and CD4+FoxP3+ in the spleens of EAE mice. Additionally, S3I-201 administration in EAE mice significantly decreased the mRNA and protein expression of Th1 and Th17 and increased those of Treg. These results suggest that S3I-201 may have novel therapeutic potential against MS.

Epsilon toxin-producing Clostridium perfringens colonize the multiple sclerosis gut microbiome overcoming CNS immune privilege.

Multiple sclerosis (MS) is a complex disease of the CNS thought to require an environmental trigger. Gut dysbiosis is common in MS, but specific causative species are unknown. To address this knowledge gap, we used sensitive and quantitative PCR detection to show that people with MS were more likely to harbor and show a greater abundance of epsilon toxin-producing (ETX-producing) strains of C. perfringens within their gut microbiomes compared with individuals who are healthy controls (HCs). Isolates derived from patients with MS produced functional ETX and had a genetic architecture typical of highly conjugative plasmids. In the active immunization model of experimental autoimmune encephalomyelitis (EAE), where pertussis toxin (PTX) is used to overcome CNS immune privilege, ETX can substitute for PTX. In contrast to PTX-induced EAE, where inflammatory demyelination is largely restricted to the spinal cord, ETX-induced EAE caused demyelination in the corpus callosum, thalamus, cerebellum, brainstem, and spinal cord, more akin to the neuroanatomical lesion distribution seen in MS. CNS endothelial cell transcriptional profiles revealed ETX-induced genes that are known to play a role in overcoming CNS immune privilege. Together, these findings suggest that ETX-producing C. perfringens strains are biologically plausible pathogens in MS that trigger inflammatory demyelination in the context of circulating myelin autoreactive lymphocytes.

Therapeutic recombinant immune complexes (rICs) inhibit T cell recruitment to the spinal cord during Experimental Autoimmune Encephalomyelitis (EAE)

Abstract Multiple sclerosis (MS) is an autoimmune neurodegenerative disease mediated by autoreactive Th1 and Th17 cells that migrate into the central nervous system (CNS) and target myelin proteins ultimately leading to neuronal damage. Current immunomodulatory treatments reduce disease severity but do not cure the disease, and they do not work for all patients. Recombinant ICs recapitulate the anti-inflammatory properties of intravenous immunoglobulin and may be a viable therapy for MS. The objective of our study was to determine if a rIC, M019, could inhibit autoreactive T cell recruitment into the CNS using the EAE model. To demonstrate that M019 could inhibit disease severity when given therapeutically, C57BL/6 mice were immunized with a CFA-MOG 35–55emulsion followed by pertussis toxin to induce EAE. Upon symptom development, mice were randomly assigned to either the vehicle or M019 treatment groups and treated with M019 or vehicle daily. Mice treated with M019 exhibited reduced clinical scores and lethality compared to vehicle treated mice. Flow cytometric analysis of T cell infiltration into the CNS revealed that M019 inhibited CD4 +and CD8 +T cell infiltration compared to vehicle treated mice with EAE. However, spleen cells from M019 treated mice had similar levels of Th17 cells and increased Th1 cells compared to the vehicle treated group. These results suggest that M019 is not inhibiting Th17 responses in the periphery but is inhibiting their recruitment into the CNS. The effect of M019 is likely indirect, as in vivo drug binding studies show that M019 binds strongly to monocytes with low level binding to T cells. Our studies suggest that M019 may be an effective therapeutic for MS patients.

Discovery and characterization of novel inhibitors of CTP synthase 1 (CTPS1) for the treatment of autoimmune and inflammatory disease

Abstract The de novo pyrimidine biosynthetic pathway is an inducible cellular program which allows the rapid synthesis of pyrimidine nucleotides in proliferating cells, and the final rate-limiting step is catalyzed by cytidine triphosphate synthase (CTPS1 or CTPS2). A CTPS1 loss-of-function mutation in humans has illustrated the essential and non-redundant role of CTPS1 in activated lymphocyte proliferation. Therefore, selective CTPS1 inhibition is an attractive approach to specifically target pathological immune activity in autoimmune and inflammatory disease. Using cryo-EM and structure-based drug design, we have identified a series of potent, orally bioavailable, CTPS1-specific inhibitors, exemplified by the compound NTX-871. In-vitro, NTX-871 significantly inhibits the proliferation of T-cell derived lines and activated primary T-cells. These inhibitory effects are reversed by the addition of exogenous cytidine, illustrating the specificity of NTX-871 for CTPS1 and the de novo pyrimidine synthesis program. NTX-871 was also tested in several mouse in-vivo PD and autoimmune disease models. Oral dosing of NTX-871 significantly reduced T-cell proliferation in an ovalbumin-induced T-cell proliferation model, and QD or BID dosing of NTX-871 significantly improved disease phenotypes in models of delayed-type hypersensitivity, collagen-induced arthritis, and experimental autoimmune encephalomyelitis.

Decreased memory persistence in Piezo1 deficient T cells ameliorates disease progression in autoimmune mouse models

Abstract To mount a successful immune response, T cells must successfully (1) migrate from the bloodstream into secondary lymphoid organs (naïve) or inflamed tissue (effector), and (2) form an effective immunological synapse for activation. Although the molecular interactions of these processes have been well described, the emergence of novel biophysical approaches has revealed that both critical processes require mechanosensing. Previously we have demonstrated that the mechanosensitive cation channel, Piezo1, forms a complex with activated integrin LFA-1, an important regulator of T cell migration and T cell receptor-triggered T cell activation. Therefore, we hypothesized that Piezo1 deficiency in T cells would diminish T cell activation and homing.To investigate Piezo1’s role on T cell function, we have generated T cell-specific Piezo1 knockout mice (P1cKO) by crossing Piezo1-floxed mice to CD4-Cre mice. Initial studies in vitro showed that under polarizing conditions P1cKO T cells produce more Th1 and Th17 inflammatory cytokines. However, when challenged with experimental autoimmune encephalomyelitis (EAE) and Graft-vs-Host Disease (GVHD), P1cKO mice showed a significant decrease in disease phenotype. Moreover, adoptive transfer mouse models of EAE show that activated P1cKO T cell transfer fails to establish disease phenotype. Upon further investigation, we found similar numbers of P1cKO T cells at sites of inflammation early in disease, but there was a decreased persistence of effector and central memory P1cKO T cells. Taken together, our data suggests that Piezo1 plays an important in role in the development and maintenance of T cell memory pools, while potentially contributing to T cell activation and migration. This project was supported by grants from the NIH (TL1 TR002549, T32 GM007250, T32 AI089474), the St. Baldrick's Foundation Innovation Fund, the Theresia G. & Stuart F. Kline Family Foundation, and the Karen & Alan Krause Pediatric Immunotherapy Innovation and Education Fund.