Moxibustion influences hippocampal microglia polarization via IL-33/ST2 pathway in Alzheimer's disease mice. / è‰¾ç¸é€šè¿‡ç™½ç»†èƒžä»‹ç´ -33/ç”Ÿé•¿åˆºæ¿€è¡¨è¾¾åŸºå› 2è›‹ç™½é€šè·¯å½±å“é˜¿å°”èŒ¨æµ·é»˜ç— å°é¼ æµ·é©¬å°èƒ¶è´¨ç»†èƒžæžåŒ–.

OBJECTIVES: To observe the effect of moxibustion on the polarization of microglia towards M2 direction in Alzheimer's disease (AD) mice through the interleukin-33 (IL-33)/growth stimulating gene 2 protein (ST2) signaling pathway. METHODS: Five-month-old APP/PS1 male mice were randomly divided into model and moxibustion (Moxi) groups, and C57BL/6J mice of the same age were as the control group, with 9 mice in each group. In the Moxi group, moxibustion was applied at "Baihui" (GV20) and "Yongquan" (KI1) for 30 min, once a day, 5 days a week for 4 weeks. The spatial learning memory ability was observed by the Morris water maze test. The relative expressions of IL-33 and ST2 in hippocampus were detected by Western blot. The positive expression of amyloid-ß (Aß), phosphorylated Tau (p-Tau), IL-33/ionized calcium binding adapter molecule 1(Iba-1), ST2/Iba-1, arginase 1 (Arg1)/Iba-1 and indu-cible nitric oxide synthase (iNOS)/Iba-1 in hippocampal CA1 region were detected by immunofluorescence. RESULTS: Compared with the control group, the escape latency of the mice in the model group was prolonged (P<0.001, P<0.01), the number of times to enter the effective area and the percentage of target quadrant swimming time were reduced (P<0.001), the positive expression of both Aß and p-Tau, the positive expression of iNOS/Iba-1 in the hippocampal CA1 region was increased (P<0.001), while the expression of IL-33 and ST2 protein in hippocampal tissue, the positive expression levels of IL-33/Iba-1, ST2/Iba-1 and Arg1/Iba-1 in hippocampal CA1 region were all decreased (P<0.05, P<0.001). After treatment, compared with the model group, the escape latency of the mice in the moxibustion group was shortened (P<0.001, P<0.01), the number of entries into the effective area and the percentage of target quadrant swimming time were increased (P<0.001), the positive expression of Aß and p-Tau in the hippocampal CA1 region, and the positive expression of iNOS/Iba-1 were decreased (P<0.001), while the expression of IL-33 and ST2 protein in the hippocampal tissue, the positive expression of IL-33/Iba-1, ST2/Iba-1 and Arg1/Iba-1 in hippocampal CA1 region were all increased (P<0.05, P<0.01, P<0.001). CONCLUSIONS: Moxibustion can improve the spatial learning and memory abilities, reduce the pathological deposition of Aß and p-Tau in APP/PS1 mice, which may be related to its function in up-regulating the IL-33/ST2 signaling pathway to regulate the polarization of microglia towards M2 direction.

[Effect of acupuncture pretreatment of "Quchi"(LI11) and "Xuehai" (SP10) on mast cells and IL-33/ST2 in rats with urticaria].

OBJECTIVE: To observe the effect of electroacupuncture (EA) pretreatment at "Quchi "(LI11) and "Xuehai "(SP10) on expression of interleukin (IL)-33, suppression of tumorigenicity 2 (ST2) and mast cell degranulation in sensitive area of skin tissue in rats with urticaria, so as to explore its mechanisms underlying prevention of urticaria. METHODS: A total of 32 male SD rats were randomly divided into blank control, model, EA preconditioning and medication groups, with 8 rats in each group. The urticaria model was established by topical injection of the prepared anti-ovalbumin serum (foreign serum, 0.1 mL/spot) along the bilateral sides of the spinal column on the back, followed by injection of mixture solution of ovalbumin, 0.5% evans blue and normal saline via the tail vein 48 h later. EA intervention (2 Hz/15 Hz, 1 mA) was applied to bilateral LI11 and SP10 for 20 min, once daily for 7 d before modeling.Back sensitization was started from the 5th day on. Rats of the medication group received gavage of loratadine, and those of the model group received gavage of the same volume of normal saline. The diameter of evans blue spots at the back skin tissue was measured; the histopathological changes of the blue spot tissues were observed by light microscope after H.E. staining. The state of degranulation of mast cells in the subcutaneous loose connective tissue was observed by using toluidine blue staining. Serum IgE and histamine contents were detected by ELISA, and the immunoactivity of IL-33 and ST2 in the skin and subcutaneous tissues of the sensitized spots (evans blue exudation spots) was observed by immunohistochemistry. RESULTS: Compared with the blank control group, the diameter of evans blue spot, degranulation rate of mast cells, serum IgE and histamine contents, and the immunoactivity of IL-33 and ST2 in the evans blue exudation spot tissues were significantly increased in the model group (P<0.01). In comparison with the model group, the increase of the above-mentioned indexes was reversed in both EA and medication groups (P<0.01，P<0.05). No significant differences were found between the EA and medication groups in down-regulating the levels of the 6 indexes. H.E. staining of the blue spot tissues of rats in the model group showed incomplete structure of the epidermal layer of the skin, unclear interface of tissues, incomplete keratinization, chaotic epidermal cells, disorderly arrangement of fibers in the dermis, and infiltration of inflammatory cells and edema, which was relatively milder in the EA and medication groups. CONCLUSION: EA preconditioning can prevent urticaria (reduce size and sensitive reactions) in rats, which may be associated with its functions in lowering the level of IgE through inhibiting IL-33 and ST2.

Betuletol, a Propolis Component, Suppresses IL-33 Gene Expression and Effective against Eosinophilia.

Propolis, a resinous substance produced by honeybees, has been used in folk medicine since ancient times due to its many biological benefits such as antitumor, antioxidant, antimicrobial, anti-inflammatory, and immunomodulatory effects. Propolis contains flavonoids, terpenoids, aromatic aldehydes, and alcohols, which vary with different climate and environmental conditions. In our study, we examined the antiallergic activity of Brazilian green propolis (BGP) and isolated the active compound that can suppress an allergy-sensitive gene, IL-33, expression and eosinophilia. Ethanolic extract of BGP freeze-dried powder was fractionated with several solvent systems, and the active fractions were collected based on activity measurement. The single active compound was found by thin-layer chromatography. Using column chromatography and NMR, the active compound was isolated and identified as 3,5,7-trihydroxy-6,4'-dimethoxyflavone, also known as betuletol. Further, the antiallergic activity of that has been examined in PMA-induced up-regulation of IL-33 gene expression in Swiss 3T3 cells. Our data showed the IL-33 gene suppression both by BGP and the isolated active compound, betuletol. We also found that betuletol suppressed ERK phosphorylation, suggesting it could be effective in suppressing IL-33 mediated eosinophilic chronic inflammation and will provide new insights to develop potent therapeutics against allergic inflammations.

Khasianine ameliorates psoriasis-like skin inflammation and represses TNF-α/NF-κB axis mediated transactivation of IL-17A and IL-33 in keratinocytes.

ETHNO-PHARMACOLOGICAL RELEVANCE: Khasianine is recently identified as a bioactive compound from Solanum nigrum L. (SNL) which is a traditional Chinese herb (named LongKui in China) and has been clinically applied for treating psoriasis in China but with limited knowledge about the active ingredients. AIM OF THE STUDY: This study tried to explore the bioactivity of Khasianine and showed that Khasianine possessed highly anti-inflammatory bioactivity which rapidly alleviated psoriasis-like mice skin inflammation. MATERIALS AND METHODS: Imiquimod induced psoriasis-like mouse model, and human keratinocytes were employed in this study. In vivo, immunohistochemistry and immunofluorescence were performed to evaluate the pathological improvement in psoriatic lesions after Khasianine treatment. In vitro, tumor necrosis factor α (TNF-α) treated HaCaT cells with or without Khasianine, were used to analyze the expression and cellular location of NF-κB p65, the expression of IL-17A and IL-33, and the binding intensity of NF-κB p65 on the promoter of IL-17A and IL-33 to understand the molecular mechanism of Khasianine mediated anti-inflammatory effect. RESULTS: Khasianine reduced infiltration of CD4+ T helper cells (Th cells) and macrophages in mice psoriatic lesions. Immunohistochemistry analysis revealed that Khasianine reduced TNF-α levels in lesions and suppressed NF-κB p65 activation as well as expression of IL-17A and IL-33 in mice epidermal keratinocytes. Further studies in human keratinocytes demonstrated that Khasianine inhibited TNF-α-induced transcriptional activation (transactivation) of NF-κB p65 such as evicting NF-κB p65 binding from the promoter regions of IL-17A and IL-33 and preventing NF-κB nuclear translocation. CONCLUSIONS: Our results suggested that Khasianine is a potent anti-inflammatory compound with the bioactivity of NF-κB inhibition and is a promising candidate for psoriasis topical therapy.

Dosing intact birch pollen grains at the air-liquid interface (ALI) to the immortalized human bronchial epithelial cell line BEAS-2B.

In real life, humans are exposed to whole pollen grains at the air epithelial barrier. We developed a system for in vitro dosing of whole pollen grains at the Air-Liquid Interface (ALI) and studied their effect on the immortalized human bronchial epithelial cell line BEAS-2B. Pollen are sticky and large particles. Dosing pollen needs resuspension of single particles rather than clusters, and subsequent transportation to the cells with little loss to the walls of the instrumentation i.e. in a straight line. To avoid high speed impacting insults to cells we chose sedimentation by gravity as a delivery step. Pollen was resuspended into single particles by pressured air. A pollen dispersion unit including PTFE coating of the walls and reduced air pressure limited impaction loss to the walls. The loss of pollen to the system was still about 40%. A linear dose effect curve resulted in 327-2834 pollen/cm2 (± 6.1%), the latter concentration being calculated as the amount deposited on epithelial cells on high pollen days. After whole pollen exposure, the largest differential gene expression at the transcriptomic level was late, about 7 hours after exposure. Inflammatory and response to stimulus related genes were up-regulated. We developed a whole pollen exposure air-liquid interface system (Pollen-ALI), in which cells can be gently and reliably dosed.

Baicalin suppresses type 2 immunity through breaking off the interplay between mast cell and airway epithelial cell.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional Japanese herbal medicine Shin'iseihaito was reported to ameliorate the airway type 2 inflammatory response in clinical and experimental studies. Airway type 2 inflammatory diseases, including bronchial asthma and eosinophilic chronic rhinosinusitis (ECRS), often coexist and interact with each other. However, it is still unclear how Shin'iseihaito exerts its pharmacological effects on cells involved in airway mucosa. AIM OF THE STUDY: This study aims to examine the direct effect of baicalin, a representative bioactive compound of Shin'iseihaito, on type 2 immune responses in human airway epithelial cells and mast cells. MATERIAL AND METHODS: We measured the plasma pharmacokinetics of flavonoids derived from Shin'iseihaito and investigated the effects of baicalin on type 2 immune responses in human airway epithelial cells and human mast cells. RESULTS: Baicalin, wogonin, and wogonoside were detected in the plasma. The maximum plasma concentration of baicalin was highest at 1610 ng/ml (3.6 µM). In the normal human bronchial epithelial cells treated with baicalin, with or without stimulation by IFN-γ, the IL-33 expression was significantly downregulated. However, baicalin treatment did not affect the levels of thymic stromal lymphopoietin and IL-25. We noted that IL-33-dependent expression of tryptase mRNA in mast cells was significantly inhibited by baicalin. Also, the expression of IL-5 in mast cells enhanced by stimulation with TSLP plus IL-1ß was significantly downregulated by baicalin treatment. Moreover, the enhancement of IL-13 expression in mast cells by IL-33 simulation was also significantly inhibited by baicalin. CONCLUSIONS: Our results prove that by breaking off the vicious circle of mast cells and airway epithelial cells, baicalin may be an effective alternative therapeutic option for the treatment of type 2 inflammatory diseases, such as ECRS and comorbid asthma.

Osthole attenuates ovalbumin­induced lung inflammation via the inhibition of IL­33/ST2 signaling in asthmatic mice.

Asthma is a common chronic inflammatory airway disease. Recent studies have reported that interleukin (IL)­33 is a potential link between the airway epithelium and Th2­type inflammatory responses, which are closely related to the progression of asthma. The IL­33 receptor, ST2, is highly expressed in group 2 innate lymphoid cells (ILC2s), Th2 cells, mast cells, eosinophils and natural killer (NK) cells. Cnidii Fructus is a Chinese herb with a long history of use in the treatment of asthma in China. Osthole is one of the major components of Cnidii Fructus. The present study examined the anti­asthmatic effects of osthole in mice and aimed to elucidate the underlying mechanisms involving the IL­33/ST2 pathway. BALB/c mice were sensitized and challenged with ovalbumin and then treated with an intraperitoneal injection of osthole (25 and 50 mg/kg). Subsequently, the airway hyper­responsiveness (AHR) and inflammation of the lungs were evaluated. The amounts of IL­4, IL­5, IL­13, interferon (IFN)­Î³ and IL­33 in the bronchoalveolar lavage fluid (BALF) were measured by Luminex assay and their mRNA levels in the lungs were measured by reverse transcription­quantitative PCR. The histopathology of the lungs was performed with H&E, PAS and Masson's staining. The expression of ST2 in the lungs was evaluated by immunohistochemistry. The data demonstrated that osthole markedly reduced AHR and decreased the number of eosinophils and lymphocytes in BALF. It was also observed that osthole significantly inhibited the release of Th2­type cytokines (IL­4, IL­5 and IL­13) and upregulated the IFN­Î³ level in BALF. Moreover, osthole significantly attenuated the IL­33 and ST2 expression in the lungs of asthmatic mice. On the whole, osthole attenuated ovalbumin­induced lung inflammation through the inhibition of IL­33/ST2 signaling in an asthmatic mouse model. These results suggest that osthole is a promising target for the development of an asthma medication.

Ruxolitinib Cream Has Dual Efficacy on Pruritus and Inflammation in Experimental Dermatitis.

The goal of this study was to elucidate the anti-pruritic and anti-inflammatory efficacy of ruxolitinib cream in experimentally-induced dermatitis. Atopic dermatitis (AD), the most common chronic relapsing inflammatory skin disease, significantly impairs patients' quality of life, with pruritus being a common complaint. The sensation of itch results from the interplay between epidermal barrier dysfunction, upregulated immune signaling and the activation of the central nervous system. The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway plays a central role in pro-inflammatory cytokine signaling in AD. Ruxolitinib cream is a potent and selective JAK1/2 inhibitor currently undergoing clinical evaluation in adults with mild-to-moderate AD (NCT03745638, NCT03920852 and NCT03745651). The efficacy of ruxolitinib cream was tested in murine models of acute and chronic dermatitis and was also characterized in an ex vivo human skin dermatitis model. Ruxolitinib cream was highly effective at ameliorating disease symptoms in multiple murine dermatitis models through downregulation of T helper (Th)2-driven inflammation, resulting in reduced skin thickening and decreased itch. Pathway analysis of mouse ear tissue and human skin explants underscored the role for ruxolitinib in ameliorating inflammation and reducing itch via modulation of the JAK-STAT pathway. Together, the data offer a strong rationale for the use of ruxolitinib cream as a potent therapeutic agent for the clinical management of atopic dermatitis.

IL (Interleukin)-33 Suppresses Abdominal Aortic Aneurysm by Enhancing Regulatory T-Cell Expansion and Activity.

Objective- Inflammation occurs during the progression of abdominal aortic aneurysm (AAA). IL (interleukin)-33 is a pleiotropic cytokine with multiple immunomodulatory effects, yet its role in AAA remains unknown. Approach and Results- Immunoblot, immunohistochemistry, and immunofluorescent staining revealed increased IL-33 expression in adventitia fibroblasts from mouse AAA lesions. Daily intraperitoneal administration of recombinant IL-33 or transgenic IL-33 expression ameliorated periaorta CaPO4 injury- and aortic elastase exposure-induced AAA in mice, as demonstrated by blunted aortic expansion, reduced aortic wall elastica fragmentation, enhanced AAA lesion collagen deposition, attenuated T-cell and macrophage infiltration, reduced inflammatory cytokine production, skewed M2 macrophage polarization, and reduced lesion MMP (matrix metalloproteinase) expression and cell apoptosis. Flow cytometry analysis, immunostaining, and immunoblot analysis showed that exogenous IL-33 increased CD4+Foxp3+ regulatory T cells in spleens, blood, and aortas in periaorta CaPO4-treated mice. Yet, ST2 deficiency muted these IL-33 activities. Regulatory T cells from IL-33-treated mice also showed significantly stronger activities in suppressing smooth muscle cell inflammatory cytokine and chemokine expression, macrophage MMP expression, and in increasing M2 macrophage polarization than those from vehicle-treated mice. In contrast, IL-33 failed to prevent AAA and lost its beneficial activities in CaPO4-treated mice after selective depletion of regulatory T cells. Conclusions- Together, this study established a role of IL-33 in protecting mice from AAA formation by enhancing ST2-dependent aortic and systemic regulatory T-cell expansion and their immunosuppressive activities.

Effect of wild grape on the signaling of histamine H1 receptor gene expression responsible for the pathogenesis of allergic rhinitis.

As expression level of allergic disease-sensitive genes are correlated with allergic symptom severity, suppression of these gene expressions could be good therapeutics. We have demonstrated that PKCδ signaling and NFAT signaling, involve in histamine H1 receptor (H1R) and IL-9 gene expressions, respectively, are responsible for the pathogenesis of allergic rhinitis. We explore anti-allergic compounds that suppress these signaling pathways and found that wild grape (WG) contains such compounds. Here, we investigated the effect of WG hot water extract (WGE) on the signaling pathways for PKCδ-mediated H1R and NFAT-mediated IL-9 gene expressions. WGE suppressed histamine/PMA-induced H1R gene up-regulation in HeLa cells. Toluene-2,4-diisocyanate (TDI)-induced H1R mRNA elevation in TDI-sensitized rats was also suppressed by WGE treatment. Treatment with WGE in combination with Awa-tea, suppresses NFAT signaling-mediated IL-9 gene, markedly alleviated nasal symptoms. Furthermore, WGE suppressed PMA-induced IL-33 gene up-regulation in Swiss 3T3 cells. Data suggest that combination of WGE, suppresses PKCδ signaling with Awa-tea, suppresses NFAT signaling would have distinct clinical and therapeutic advantages as a substitute for anti-allergic drugs. In addition, as the expression level of IL-33 mRNA was correlated with the blood eosinophils number in patients with pollinosis, WG could alleviate eosinophilic inflammation through the suppression of IL-33 gene expression. J. Med. Invest. 65:242-250, August, 2018.

Regulation of the IL-33/ST2 pathway contributes to the anti-inflammatory effect of acupuncture in the ovalbumin-induced murine asthma model.

BACKGROUND: Bronchial asthma is a chronic airway inflammatory disease which has three main pathological features: airway hyperresponsiveness (AHR), airway remodelling, and chronic inflammation. Acupuncture is known to be an effective integrative medical therapy that has been used in the treatment of several chronic diseases, including bronchial asthma. The aim of the current study was to evaluate the effects of acupuncture on inflammation and regulation of the IL-33/ST2 pathway in a mouse model of asthma. METHODS: The murine asthma model was established by both injection and inhalation of ovalbumin (OVA). Within 24 hours of the last OVA challenge, lung function was assessed by measurement of the airway resistance (RL) and lung dynamic compliance (Cdyn). Pulmonary tissues were collected for the detection of pathological changes and mucus secretion. Serum levels of tumour necrosis factor α (TNF-α), interleukin (IL)-1ß, IL-33 and sST2 (secreted ST2) were detected by ELISA. Th17 cell proportions and counts in bronchoalveolar lavage fluid (BALF) were analysed by flow cytometry. RESULTS: The results showed that AHR, chronic inflammation and mucus secretion were significantly suppressed by acupuncture treatment. RL decreased while Cdyn increased after acupuncture treatment. There was an apparent decrease in the serum concentrations of certain pro-inflammatory cytokines, such as TNF-α, IL-1ß and IL-33, and an increase in sST2 level compared with untreated asthmatic mice. Acupuncture also reduced the CD4 +IL-17A+ cell proportion and counts in BALF. CONCLUSION: Acupuncture effectively protects lung function and attenuates airway inflammation in the OVA-induced mouse model of asthma, which supports the role of acupuncture as a potential therapy in asthma treatment.

Astrocyte-derived interleukin-33 promotes microglial synapse engulfment and neural circuit development.

Neuronal synapse formation and remodeling are essential to central nervous system (CNS) development and are dysfunctional in neurodevelopmental diseases. Innate immune signals regulate tissue remodeling in the periphery, but how this affects CNS synapses is largely unknown. Here, we show that the interleukin-1 family cytokine interleukin-33 (IL-33) is produced by developing astrocytes and is developmentally required for normal synapse numbers and neural circuit function in the spinal cord and thalamus. We find that IL-33 signals primarily to microglia under physiologic conditions, that it promotes microglial synapse engulfment, and that it can drive microglial-dependent synapse depletion in vivo. These data reveal a cytokine-mediated mechanism required to maintain synapse homeostasis during CNS development.

Eupatilin, an activator of PPARα, inhibits the development of oxazolone-induced atopic dermatitis symptoms in Balb/c mice.

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is the main lipophilic flavonoid obtained from the Artemisia species. Eupatilin has been reported to have anti-apoptotic, anti-oxidative and anti-inflammatory activities. Previously, we found that eupatilin increases transcriptional activity and expression of peroxisome proliferator-activated receptor α (PPARα) in a keratinocyte cell line and acts as an agonist of PPARα. PPARα agonists ameliorate atopic dermatitis (AD) and restore the skin barrier function. In this study, we confirmed that the effects of eupatilin improved AD-like symptoms in an oxazolone-induced AD-like mouse model. Furthermore, we found that eupatilin suppressed the levels of serum immunoglobulin E (IgE), interleukin-4 (IL-4), and AD involved cytokines, such as tumor necrosis factor α (TNFα), interferon-γ (IFN-γ), IL-1ß, and thymic stromal lymphopoietin (TSLP), IL-33, IL-25 and increased the levels of filaggrin and loricrin in the oxazolone-induced AD-like mouse model. Taken together, our data suggest that eupatilin is a potential candidate for the treatment of AD.

The significance of the levels of IL-4, IL-31 and TLSP in patients with asthma and/or rhinitis.

AIM: To investigate the clinical significance of the levels of IL-4, IL-33 and thymic stromal lymphopoietin (TLSP) in patients with asthma and/or rhinitis, then do the simple verification in animals. METHODS: Levels of IL-4 IL-31, IL-33 and TLSP were detected by ELISA and real-time PCR in 64 asthma patients (sIgE[+]: 32 cases, sIgE[-]: 32 cases), 64 rhinitis patients (sIgE[+]: 32 cases, sIgE[-]: 32 cases), 64 asthma complicated with allergic rhinitis patients (sIgE[+]: 32 cases, sIgE[-]: 32 cases) and 32 healthy controls. Then we detected the IL-4, IL-31, IL-33 and TLSP in the sensitized mice. RESULTS: Results showed that levels of IL-4, IL-31, IL-33 and TSLP in asthma and rhinitis patients, and those complicated with allergic rhinitis, had significant differences compared with the control group (p < 0.05). It was found that the indicators of mugwort and dust mite allergic patients were significantly higher than that of other allergic patients (p < 0.05). We got the same tendency in in vivo experiments. CONCLUSION: IL-4, IL-31, IL-33 and TSLP may be involved in the pathogenesis of asthma and rhinitis; dust mite and mugwort allergy could increase them significantly.

Pollen/TLR4 Innate Immunity Signaling Initiates IL-33/ST2/Th2 Pathways in Allergic Inflammation.

Innate immunity has been extended to respond environmental pathogen other than microbial components. Here we explore a novel pollen/TLR4 innate immunity in allergic inflammation. In experimental allergic conjunctivitis induced by short ragweed (SRW) pollen, typical allergic signs, stimulated IL-33/ST2 signaling and overproduced Th2 cytokine were observed in ocular surface, cervical lymph nodes and isolated CD4+ T cells of BALB/c mice. These clinical, cellular and molecular changes were significantly reduced/eliminated in TLR4 deficient (Tlr4-d) or MyD88 knockout (MyD88-/-) mice. Aqueous SRW extract (SRWe) directly stimulated IL-33 mRNA and protein expression by corneal epithelium and conjunctiva in wild type, but not in Tlr4-d or MyD88-/- mice with topical challenge. Furthermore, SRWe-stimulated IL-33 production was blocked by TLR4 antibody and NF-kB inhibitor in mouse and human corneal epithelial cells. These findings for the first time uncovered a novel mechanism by which SRW pollen initiates TLR4-dependent IL-33/ST2 signaling that triggers Th2-dominant allergic inflammation.

Effects of IL-33/ST2 pathway in acute inflammation on tissue damage, antioxidative parameters, magnesium concentration and cytokines profile.

AIM: The aim of this study was to examine the role of IL-33/ST2 pathway in a pathogenesis of acute inflammation and its effects on tissue damage, antioxidative capacity, magnesium concentration and cytokine profile in acutely inflamed tissue. MATERIAL AND METHODS: Male mice were randomly divided in four groups: wild-type control group (WT-C), ST2 knockout control group (KO-C), wild-type inflammatory group (WT-I), and ST2 knockout inflammatory group (KO-I). Acute inflammation was induced in WT-I and KO-I by intramuscular injection of turpentine oil, while mice in WT-C and KO-C were treated with saline. After 12h, animals were euthanized, and blood was collected for determination of creatine kinase (CK) and aspartate transaminase (AST) activity. The treated tissue was used for histopathological analysis, determination of volume density of inflammatory infiltrate (Vdii) and necrotic fiber (Vdnf), gene expression of interleukin (IL)-33, ST2, tumor necrosis factor alpha (TNF-alpha), IL-6, IL-12p35, and transforming growth factor beta (TGF-beta), concentration of magnesium (Mg), copper (Cu), selenium (Se), manganese (Mn) and reduced glutathione (GSH), and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity. RESULTS: Presence of inflammatory infiltration and necrosis in the treated tissue was histopathologically confirmed in WT-I and KO-I. Vdii was significantly higher in WT-I when compared to KO-I, whereas Vdnf did not significantly differ between WT-I and KO-I. CK and AST significantly increased in both inflammatory groups when compared to corresponding control groups. However, the values of CK and AST were significantly higher in WT-I than in KO-I. Mg in the treated tissue was significantly lower in WT-I in comparison to WT-C and KO-I, while there was no significant difference between KO-C and KO-I. There was no significant difference in Cu, Se, and Mn in the treated tissue between WT-C, KO-C, WT-I and KO-I. Gene expression of IL-33 in the treated tissue increased in both inflammatory groups when compared to the corresponding control groups, but it was significantly higher in KO-I than in WT-I. Gene expression of ST2 in the treated tissue was significantly higher in WT-I than in WT-C. Gene expression of TNF-alpha, IL-6, and IL-12p35 in the treated tissue was significantly higher in WT-I and KO-I than in the corresponding control groups, and IL-6 was significantly higher in KO-C than in WT-C. TGF-beta gene expression in the treated tissue was significantly higher in KO-I when compared to WT-I, while there was no difference between WT-C and KO-C. SOD activity decreased at the site of acute inflammation in both inflammatory groups, while the GPx activity increased. GSH in the treated tissue was significantly higher in KO-I than in KO-C or WT-I. CONCLUSION: The results of our study have indicated, to our knowledge for the first time, that IL-33/ST2 pathway plays a role in enhancing inflammation and tissue damage at the site of acute inflammation by affecting the concentration of magnesium and GSH, important for antioxidative capacity, as well as gene expression of anti-inflammatory cytokine TGF-beta.

Murine allergic rhinitis and nasal Th2 activation are mediated via TSLP- and IL-33-signaling pathways.

Thymic stromal lymphopoietin (TSLP) and IL-33 are epithelium-derived proallergic cytokines that contribute to allergic diseases. Although the involvement of TSLP in allergic rhinitis (AR) is suggested, the exact role of TSLP in AR is poorly understood. Furthermore, the relative contribution of TSLP and IL-33 in nasal allergic responses has not been described. In this study, we examined the roles of TSLP and IL-33 in AR by analyzing acute and chronic AR models. Acute AR mice were intraperitoneally immunized with ragweed, then intranasally challenged with ragweed pollen for four consecutive days. Chronic AR mice were nasally administrated ragweed pollen on consecutive days for 3 weeks. In both models, TSLP receptor (TSLPR)-deficient mice showed defective sneezing responses and reduced serum ragweed-specific IgE levels compared with wild-type (WT) mice. Analyses of bone-marrow chimeric mice demonstrated that hematopoietic cells were responsible for defective sneezing in TSLPR-deficient mice. In addition, FcεRI(+)-cell-specific TSLPR-deficient mice showed partial but significant reduction in sneezing responses. Of note, Th2 activation and nasal eosinophilia were comparable between WT and TSLPR-deficient mice. ST2- and IL-33-deficient mice showed defective Th2 activation and nasal eosinophilia to acute, but not chronic, ragweed exposure. TSLPR and ST2 double-deficient mice showed defective Th2 activation and nasal eosinophilia even after chronic ragweed exposure. These results demonstrate that TSLPR signaling is critical for the early phase response of AR by controlling the IgE-mast-cell/basophil pathway. The IL-33/ST2 pathway is central to nasal Th2 activation during acute allergen exposure, but both TSLPR and ST2 contribute to Th2 responses in chronically allergen-exposed mice.