Project description:The immune response to viral infection is ideally rapid and specific, resulting in viral clearance and establishment of immune memory. Some viruses such as HIV can evade such responses leading to chronic infection, while others like Influenza A can elicit a severe inflammatory response with immune-related complications including death. Cytokines play a major role in shaping the appropriate outcomes to infection. While Interleukin-7 (IL-7) has a critical role in T and B cell development, treatment with IL-7 has recently been shown to aid the adaptive T cell response in clearance of chronic viral infection. In contrast, the IL-7-related cytokine thymic stromal lymphopoietin (TSLP) has a limited role in lymphocyte development but is important in the immune response to parasitic worms and allergens. The role for these cytokines in the immune response to an acute viral infection is unclear. IL-7 and TSLP share IL-7R? as part of their heterodimeric receptors with the gamma common chain (?c) and TSLPR, respectively. We investigated the role of IL-7 and TSLP in the primary immune response to influenza A infection using hypomorphic IL-7R? (IL-7R?(449F)) and TSLPR(-/-) mice. We found that IL-7, but not TSLP, plays an important role in control of influenza A virus. We also showed that IL-7 signaling was necessary for the generation of a robust influenza A-specific CD4 and CD8 T cell response and that this requirement is intrinsic to CD8 T cells. These findings demonstrate a significant role for IL-7 during acute viral infection.
Project description:Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine expressed in skin, gut, lungs, and thymus. TSLP signals via a TSLP receptor (TSLPR), a heterodimer of the IL-7 receptor alpha chain and the TSLPR chain. The TSLPR chain is closely related to the common receptor gamma chain that is expressed on a wide range of cell types in the adaptive and innate immune system. TSLP exerts a profound influence on the polarization of dendritic cells to drive T helper (Th) 2 cytokine production. TSLP also directly promotes T-cell proliferation in response to T-cell receptor activation and Th2 cytokine production and supports B-cell expansion and differentiation. TSLP further amplifies Th2 cytokine production by mast cells and natural killer T cells. These properties confer on TSLP a critical role in driving Th2-mediated inflammation. This role is supported by the finding that TSLP expression is upregulated in keratinocytes of atopic dermatitis skin lesions and in bronchial epithelial cells in asthma.
Project description:Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine that acts on multiple cell lineages, including dendritic cells, T cells, B cells, neutrophils, mast cells, eosinophils and innate lymphoid cells, affecting their maturation, survival and recruitment. It is best known for its role in promoting type 2 immune responses such as in allergic diseases and, in 2021, a monoclonal antibody targeting TSLP was approved for the treatment of severe asthma. However, it is now clear that TSLP has many other important roles in a variety of settings. Indeed, several genetic variants for TSLP are linked to disease severity, and chromosomal alterations in TSLP are common in certain cancers, indicating important roles of TSLP in disease. In this Review, we discuss recent advances in TSLP biology, highlighting how it regulates the tissue environment not only in allergic disease but also in infectious diseases, inflammatory diseases and cancer. Encouragingly, therapies targeting the TSLP pathway are being actively pursued for several diseases.
Project description:BackgroundThe fetal immune system is a critical window of development. The epithelial cell-derived cytokines, thymic stromal lymphopoietin (TSLP), and interleukin-33 (IL-33) have received attention for their role in allergic responses but not been studied during this critical window. The objectives were to assess correlations among IL-33, TSLP, and IgE in umbilical cord blood samples and identify prenatal predictors of these biomarkers.MethodsThis study utilized data and banked cord blood collected in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a trans-Canada cohort study of 2001 pregnant women. Our analytic sample comprised the 1254 women with a singleton, term birth with a cord blood sample. Spearman correlation coefficients (SCC) and logistic regression models were used to examine associations between biomarkers and identify potential predictors of elevated biomarker levels.ResultsThymic stromal lymphopoietin and IL-33 were more strongly correlated with each other (SCC = 0.75, p < 0.0001) than with IgE (IL-33 SCC = 0.14, TSLP SCC = 0.21). Maternal allergy, heavy street traffic, and elevated birth weight were significantly associated with jointly elevated TSLP and IL-33 levels, whereas maternal age and female infant sex were inversely associated with elevated IgE.ConclusionsIn this population of Canadian women and infants, TSLP and IL-33 were detectable in cord blood, more strongly correlated with each other than with IgE, and associated with maternal characteristics indicative of inflammatory responses. This study motivates investigation into the value of cord blood IL-33 and TSLP levels as childhood allergy predictors and raises interesting questions regarding in utero coordinated regulation of these cytokines.
Project description:Objective[corrected] Systemic sclerosis (SSc) is an autoimmune disease characterised by progressive fibrosis. Although SSc shares pathogenetic features with other autoimmune diseases, the participation of profibrotic Th2 cytokines is unique to SSc, but the mechanisms of Th2 skewing are unknown. We have analysed the expression and function of thymic stromal lymphopoietin (TSLP), a central regulator of Th2-mediated allergic inflammation, in human SSc, primary lung fibrosis and in a mouse model of scleroderma.MethodsTSLP expression was analysed by immunohistochemistry in human SSc skin, primary lung fibrosis and mouse bleomycin-induced skin fibrosis, and by quantitative RT-PCR in mouse skin and cultured fibroblasts. The regulation of TSLP expression by specific toll-like receptors (TLR)-2, -3 and -4 agonists was analysed in human dermal fibroblast cultures. The role of TSLP in skin fibrosis and local cytokine expression was analysed in TSLP receptor (TSLPR)-deficient mice.ResultsTSLP was overexpressed by epithelial cells, mast cells and fibroblasts in human SSc skin and lung fibrosis, and in the bleomycin model of scleroderma. In cultured human and mouse skin fibroblasts, TSLP expression was inducible by activation of TLR, particularly TLR3. In TSLPR-deficient mice, bleomycin-induced fibrosis was significantly reduced in parallel with significantly reduced local expression of IL-13.ConclusionsThese data provide the first evidence of TSLP overexpression in SSc and other non-allergic fibrotic conditions, and demonstrate a profibrotic role that is potentially meditated by specific changes in the local cytokine milieu. Thus, modulating TSLP may have antifibrotic therapeutic implications.
Project description:Originally shown to promote the growth and activation of B cells, thymic stromal lymphopoietin (TSLP) is now known to have wide-ranging impacts on both hematopoietic and nonhematopoietic cell lineages, including dendritic cells, basophils, eosinophils, mast cells, CD4?, CD8? and natural killer T cells, B cells and epithelial cells. While TSLP's role in the promotion of TH2 responses has been extensively studied in the context of lung- and skin-specific allergic disorders, it is becoming increasingly clear that TSLP may impact multiple disease states within multiple organ systems, including the blockade of TH1/TH17 responses and the promotion of cancer and autoimmunity. This chapter will highlight recent advances in the understanding of TSLP signal transduction, as well as the role of TSLP in allergy, autoimmunity and cancer. Importantly, these insights into TSLP's multifaceted roles could potentially allow for novel therapeutic manipulations of these disorders.
Project description:The mast cell localization to airway smooth muscle (ASM) bundle in asthma is important in the development of disordered airway physiology. Thymic stromal lymphopoietin (TSLP) is expressed by airway structural cells. Whether it has a role in the crosstalk between these cells is uncertain. We sought to define TSLP expression in bronchial tissue across the spectrum of asthma severity and to investigate the TSLP and TSLP receptor (TSLPR) expression and function by primary ASM and mast cells alone and in coculture.TSLP expression was assessed in bronchial tissue from 18 subjects with mild to moderate asthma, 12 with severe disease, and nine healthy control subjects. TSLP and TSLPR expression in primary mast cells and ASM was assessed by immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assay, and its function was assessed by calcium imaging. The role of TSLP in mast cell and ASM proliferation, survival, differentiation, synthetic function, and contraction was examined.TSLP expression was increased in the ASM bundle in mild-moderate disease. TSLP and TSLPR were expressed by mast cells and ASM and were functional. Mast cell activation by TSLP increased the production of a broad range of chemokines and cytokines, but did not affect mast cell or ASM proliferation, survival, or contraction.TSLP expression by the bronchial epithelium and ASM was upregulated in asthma. TSLP promoted mast cell synthetic function, but did not contribute to other functional consequences of mast cell-ASM crosstalk.
Project description:Adaptive immune responses regulate the development of atherosclerosis, with a detrimental effect of type 1 but a protective role of type 2 immune responses. Immunization of Apolipoprotein E-deficient (ApoE-/- ) mice with Freund's adjuvant inhibits the development of atherosclerosis. However, the underlying mechanisms are not fully understood. Thymic stromal lymphopoietin (TSLP) is an IL7-like cytokine with essential impact on type 2 immune responses (Th2). Thymic stromal lymphopoietin is strongly expressed in epithelial cells of the skin, but also in various immune cells following appropriate stimulation. In this study, we investigated whether TSLP may be crucial for the anti-atherogenic effect of Freund's adjuvant. Subcutaneous injection of complete Freund's adjuvant (CFA) rapidly led to the expression of TSLP and IL1? at the site of injection. In male mice, CFA-induced TSLP occurred in immigrated monocytes-and not epithelial cells-and was dependent on NLRP3 inflammasome activation and IL1?-signalling. In females, CFA-induced TSLP was independent of IL1? and upon ovariectomy. CFA/OVA led to a more pronounced imbalance of the T cell response in TSLPR-/- mice, with increased INF?/IL4 ratio compared with wild-type controls. To test whether TSLP contributes to the anti-atherogenic effects of Freund's adjuvant, we treated ApoE-/- and ApoE-/- /TSLPR-/- mice with either CFA/IFA or PBS. ApoE-/- mice showed less atherogenesis upon CFA/IFA compared with PBS injections. ApoE-/- /TSLPR-/- mice had no attenuation of atherogenesis upon CFA/IFA treatment. Freund's adjuvant executes significant immune-modulating effects via TSLP induction. TSLP-TSLPR signalling is critical for CFA/IFA-mediated attenuation of atherosclerosis.
Project description:Ni is the most frequent cause of contact allergy induced by metals. However, the underlying mechanism of this induction is unknown. Our previous research demonstrates that activation of dendritic cells (DCs) through p38MAPK/MKK6 is required for Ni-induced allergy in mice. In the current study, we investigated the cellular and molecular mechanisms underlying Ni-induced allergy using a mouse model that involves injecting Ni into the ear, with or without Freund's incomplete or complete adjuvants. Nickel had greater potential to cause allergic reactions compared with palladium and gold. Among the proteins expressed at higher levels in mice with Ni-induced allergy, we focused on thymic stromal lymphopoietin (TSLP), which is produced in abundance by keratinocytes. We detected increased expression of the TSLP receptor (TSLPR) in DCs from cervical lymph nodes of mice with Ni-induced allergy, suggesting that DCs in ear tissues were activated through TSLPR signaling induced by keratinocyte-derived TSLP. Furthermore, delayed-type hypersensitivity reactions in mice with Ni-induced allergy were decreased significantly by injection of a Tslp-short interfering RNA along with atelocollagen in the ear skin. These results suggest that Ni allergy may be triggered by a TSLP/TSLPR-mediated interaction between epithelial and immune cells.
Project description:Thymic stromal lymphopoietin (TSLP) was initially demonstrated to be critical in regulating inflammatory responses among various allergic disorders (such as atopic dermatitis, food allergy, and asthma). Although two isoforms (short form and long form) of TSLP have been demonstrated in human tissues, the long form of TSLP (lfTSLP) is strongly implicated in the pathogenesis of allergies and cutaneous immune-mediated diseases. The immunomodulatory activity of lfTSLP varies widely, driving T helper (Th) cells polarizing Th2 and Th17 immune responses and inducing itch. Moreover, lfTSLP is closely associated with skin fibrosis, epidermal hyperplasia, angiogenesis, and homeostatic tolerogenic regulations. This review highlights significant progress from experimental and clinical studies on lfTSLP in cutaneous immune-mediated diseases (atopic dermatitis, psoriasis, bullous pemphigoid, systemic sclerosis, chronic spontaneous urticaria, Behçet's disease, vitiligo, rosacea, systemic lupus erythematosus, and alopecia areata). We also offer original insights into the pleiotropic properties of the cytokine TSLP in various pathophysiological conditions, with significant clinical implications of TSLP-targeted therapies for immune-mediated skin diseases in the future.