Th17 cell-mediated immune response in a subpopulation of dogs with idiopathic epilepsy

Background Canine idiopathic epilepsy (IE) is a common neurological disease with severe impact on the owner´s and the dog’s quality of life. A subpopulation of dogs with IE does not respond to antiseizure drugs (non-responder). Th17 cells (T helper cells) and their proinflammatory Interleukin-17 (IL-17) are part of the immune system and previous studies showed their involvement in the pathogenesis of several autoimmune diseases. Non-responder might have an abnormal immune response against structures of the central nervous system. To discover a new aetiology of canine IE and thereby optimising the therapy of intractable IE, this prospective study aimed to investigate Th17 cells and IL-17 in dogs with IE. The underlying hypothesis was that in some dogs with IE a Th17 cell-mediated immune response could be detectable. Methods 57 dogs with IE and 10 healthy dogs (control group, C) were enrolled in the study. EDTA blood was taken to measure Th17 cells by flow cytometry. IL-17 was measured in 35 cerebrospinal fluid (CSF) and 33 serum samples using an enzyme-linked immunosorbent assay (ELISA). It was investigated whether there was a significant increase of stimulated Th17 cells in blood samples or of IL-17 in serum and CSF samples of dogs with IE in comparison to C. Correlations between the amount of Th17 cells/μL or IL-17 and different clinical parameters e.g. seizure frequency, seizure type, seizure severity or treatment response were evaluated. Additionally, Th17 cells/μL were randomly controlled of 17 dogs with IE and were examined for changes over time and in relation to treatment response. Results Ten dogs with IE had strongly elevated stimulated Th17 cells/μL within the blood (>100 Th17 cells/μL). A slight positive correlation between stimulated Th17 cells/μL and seizure severity (p = 0.046; rSpear = 0.27) was proven in these dogs. In addition, 4/10 dogs with elevated Th17 levels experienced cluster seizures and status epilepticus in comparison to 9% of the dogs with non-elevated Th17 levels (<100 Th17 cells/μL). Dogs with IE had significantly higher IL-17 values in CSF and serum samples compared to C (p<0.001; p<0.002; respectively). Conclusion In single dogs with IE, strongly increased amounts of Th17 cells were detectable and dogs with elevated Th17 cells seemed to have a greater risk for experiencing a combination of cluster seizures and status epilepticus. Therefore, an underlying Th17-cell mediated immune response was suspected and hence anti-inflammatory drugs could be indicated in these single cases with intractable epilepsy.

SPRC Suppresses Experimental Periodontitis by Modulating Th17/Treg Imbalance

Object: The aims of the study were to explore the protective effects of S-propargyl-cysteine (SPRC) on periodontitis and to determine the underlying mechanisms.Methods: A rat periodontitis model was constructed by injecting LPS and SPRC (0, 25, and 50 mg/kg/d) was administered intraperitoneally. H2S and CSE level were detected. The alveolar bone level was evaluated by micro-CT, HE staining and methylene blue staining analysis. Inflammation-related factors, Treg and Th17 cells were detected by immunohistochemistry, RT-PCR, immunofluorescence, Western blot and flow cytometry. Phosphorylation levels of ERK1/2 and CREB were analysed.Results: The administration of SPRC significantly increased the expression of CSE in the gingival tissue and the concentration of endogenous H2S in the peripheral blood. Simultaneously, SPRC significantly inhibited the resorption of alveolar bone based on the H&amp;E staining, micro-CT and methylene blue staining analysis. Compared with the periodontitis group, the levels of IL-17A, IL-10 were downregulated and IL-6,TGF-β1 were upregulated in the SPRC groups. In the SPRC group, the percentage of TH17 cells and the expression of ROR-γt were downregulated, while the percentage of Tregs and the expression of Foxp3 were upregulated accompanied with inhibition of phosphorylation ERK1/2 and CREB.Conclusion: SPRC can prevent the progression of periodontitis by regulating the Th17/Treg balance by inhibition of the ERK/CREB signalling pathway.

Critical Involvement of CD44 in T Helper Type 2 Cell-Mediated Eosinophilic Airway Inflammation in a Mouse Model of Acute Asthma

Interactions between CD44 and hyaluronan (HA) are crucial for recruiting leukocytes to inflamed tissues. This review summarizes findings from our studies of the roles of CD44-HA interactions in leukocyte trafficking, with a particular focus on airway T helper type 2 (Th2) cells in mouse models of acute asthma. In a mite allergen-induced model of acute asthma, intraperitoneal injection of anti-CD44 monoclonal antibodies blocked lymphocytes and eosinophils from accumulating in the lung, and suppressed both the antigen-induced increase in Th2 cytokines in the bronchoalveolar lavage fluid (BALF) and airway hyperresponsiveness (AHR). CD44 deficiency was associated with decreased mite allergen-induced Th2 cell-mediated airway inflammation and AHR in sensitized mice. Asthmatic responses to antigen-sensitized splenic CD4+ T cells transferred from CD44-deficient mice were weaker than in wild-type mice. Administration of anti-CD44 monoclonal antibodies preferentially suppressed the airway accumulation of antigen-specific Th2 cells induced by antigen challenge, without affecting Th1 and Th17 cells. Increased HA-binding ability of CD44 and expression of Neu1 sialidase were observed on antigen-specific Th2 cells compared with antigen-specific Th1 and Th17 cells. Finally, in a mouse model of acute asthma, neuraminidase 1-deficient SM/J mice exhibited a lower Th2 cytokine concentration and a lower absolute Th2 cell number in the BALF, as well as an attenuated AHR. Our findings indicate that CD44 critically contributes to the antigen challenge-induced airway accumulation of antigen-specific Th2 cells, without affecting Th1 and Th17 cells, in mice. Furthermore, neuraminidase 1 activity is necessary for the interaction between HA and CD44, and Th2 cell-mediated airway inflammation.

Gut dysbiosis is associated with acceleration of lupus nephritis

The gut microbiota (GM) exerts a strong influence over the host immune system and dysbiosis of this microbial community can affect the clinical phenotype in chronic inflammatory conditions. To explore the role of the GM in lupus nephritis, we colonized NZM2410 mice with Segmented Filamentous Bacteria (SFB). Gut colonization with SFB was associated with worsening glomerulonephritis, glomerular and tubular immune complex deposition and interstitial inflammation compared to NZM2410 mice free of SFB. With SFB colonization mice experienced an increase in small intestinal lamina propria Th17 cells and group 3 innate lymphoid cells (ILC3s). However, although serum IL-17A expression was elevated in these mice, Th17 cells and ILC3s were not detected in the inflammatory infiltrate in the kidney. In contrast, serum and kidney tissue expression of the macrophage chemoattractants MCP-1 and CXCL1 were significantly elevated in SFB colonized mice. Furthermore, kidney infiltrating F4/80+CD206+M2-like macrophages were significantly increased in these mice. Evidence of increased gut permeability or “leakiness” was also detected in SFB colonized mice. Finally, the intestinal microbiome of SFB colonized mice at 15 and 30 weeks of age exhibited dysbiosis when compared to uncolonized mice at the same time points. Both microbial relative abundance as well as biodiversity of colonized mice was found to be altered. Collectively, SFB gut colonization in the NZM2410 mouse exacerbates kidney disease, promotes kidney M2-like macrophage infiltration and overall intestinal microbiota dysbiosis.

Forsythoside A Alleviates Imiquimod-Induced Psoriasis-like Dermatitis in Mice by Regulating Th17 Cells and IL-17A Expression

Psoriasis is a recurrent inflammatory skin disease characterized by redness and scaly skin lesions with itchy or painful sensations. Forsythoside A, one of the main active compounds isolated from the fruit of Forsythia suspensa, has been widely applied to treat inflammatory diseases in the clinical use of traditional oriental medicine. However, the effect of forsythoside A on psoriasis remains unclear. This study aimed to explore the therapeutic effects and immune regulation of forsythoside A on psoriasis. C57BL/6 mice were divided into six groups and treated with imiquimod cream on their shaved back skin to induce psoriasis-like dermatitis. Different doses of forsythoside A (5 mg/kg, 10 mg/kg, or 20 mg/kg) were administered to the respective treatment groups. Skin redness, scaling, and ear thickness were measured; keratinocyte proliferation and inflammatory cytokine expression were detected by hematoxylin–eosin and immunohistochemical staining. Th17 cells in the inguinal lymph nodes were detected by flow cytometric analysis. IL-17A levels were measured using ELISA. The results showed that forsythoside A relieved psoriatic skin symptoms such as skin redness, thickness, scaling, and reduced epidermal thickening. The expression of IL-6, IL-17, and Ki-67 was downregulated in the forsythoside-A-treated groups. Th17 cell expression in inguinal lymph nodes and IL-17A secretion was suppressed by forsythoside A. In conclusion, forsythoside A was found to alleviate imiquimod-induced psoriasis-like dermatitis in mice by suppressing Th17 development and IL-17A secretion. These findings demonstrate the feasibility of forsythoside A in treating human psoriasis.

Melatonin, an Endogenous Hormone, Modulates Th17 Cells via the Reactive Oxygen Species/TXNIP/HIF-1α Axis to Alleviate Autoimmune Uveitis

Background Melatonin, an indoleamine produced by the pineal gland, plays a pivotal role in maintaining circadian rhythm homeostasis. Recently, the strong antioxidant and anti-inflammatory properties of melatonin have attracted attention of researchers. We evaluated the therapeutic efficacy of melatonin in experimental autoimmune uveitis (EAU), which is a representative animal model of human autoimmune uveitis. Methods EAU was induced in mice via immunization with the peptide interphotoreceptor retinoid binding protein 1-20 (IRBP1−20). melatonin was then administered via intraperitoneal injection to induce protection against EAU. With EAU induction for 14 days, clinical and histopathological scores were employed to evaluate the disease progression. T lymphocytes accumulation, the expression of inflammatory cytokines in the retinas were assessed via flow cytometry and RT-PCR. In vivo and in vitro experiments, T helper 1 (Th1), T helper 17 (Th17) and regulatory T (Treg) cells were detected via flow cytometry, the level reactive oxygen species(ROS) from CD4+ cells were tested via flow cytometry, and the expression of thioredoxin-interacting protein (TXNIP) and hypoxia-inducible factor 1 alpha (HIF-1α)proteins were also quantified via western blot analysis, to elucidate the mechanism of melatonin inhibiting EAU. Results Melatonin treatment resulted in notable attenuation of ocular inflammation in EAU mice, evidenced by decreasing optic disc edema, few signs of retinal vasculitis, and minimal retinal and choroidal infiltrates. Mechanistic studies revealed that melatonin restricted the proliferation of peripheral Th1 and Th17 cells and potentiated Treg cells by suppressing their transcription factors. In vitro studies corroborated that melatonin restrains the polarization of retina-specific T cells towards Th17 and Th1 cells in addition to enhancing the proportion of Treg cells. Pretreatment of retina-specific T cells with melatonin failed to induce EAU in naïve recipients. Furthermore, the ROS/ TXNIP/ HIF-1α pathway was shown to mediate the therapeutic effect of melatonin in EAU. Conclusions Melatonin regulates autoimmune T cells by restraining effector T cells and facilitating Treg generation, indicating that melatonin could be a hopeful treatment alternative for autoimmune uveitis.

The Immuno-Modulatory Activities of Pentaherbs Formula on Ovalbumin-Induced Allergic Rhinitis Mice via the Activation of Th1 and Treg Cells and Inhibition of Th2 and Th17 Cells

Allergic rhinitis (AR) is a highly prevalent allergic disease induced by immunoglobulin (Ig) E-mediated hypersensitivity reaction at the nasal epithelium against inhaled allergens. Previous studies have demonstrated that Pentaherbs formula (PHF), a modified herbal formula comprising five herbal medicines (Flos Lonicerae, Herba Menthae, Cortex Phellodendri, Cortex Moutan and Rhizoma Atractylodis), could suppress various immune effector cells to exert anti-inflammatory and anti-allergic effects in allergic asthma and atopic dermatitis. The present study aimed to further determine the anti-inflammatory activities of PHF in an ovalbumin (OVA)-induced AR BALB/c mouse model. Nasal symptoms such as sneezing and nose rubbing were recorded and the serum total IgE and OVA-specific IgG1, as well as interleukin (IL)-4, IL-5, IL-10, IL-13, chemokines CXCL9 CXCL10, and tumor necrosis factor (TNF)-α concentrations in nasal lavage fluid (NALF) were measured during different treatments. Effects of PHF on the expression of inflammatory mediators in the sinonasal mucosa were quantified using real-time QPCR. PHF was found to suppress allergic symptoms, infiltration of inflammatory cells, and hyperplasia of goblet cells in the nasal epithelium of the OVA-induced AR mice. PHF could reduce OVA-specific IgG1 level in serum, and TNF-α and IL-10 in nasal lavage fluid (NALF), significantly up-regulate the splenic regulatory T (Treg) cell level, increase the Type 1 helper T cell (Th1)/Type 2 helper T cell (Th2) ratio, and reduce the Th17 cells (all p < 0.05). PHF could also alleviate in situ inflammation in sinonasal mucosa of OVA-induced AR mice. In conclusion, oral treatment of PHF showed immuno-modulatory activities in the OVA-induced AR mice by regulating the splenic T cell population to suppress the nasal allergy symptoms and modulating inflammatory mediators, implicating that PHF could be a therapeutic strategy for allergic rhinitis.