The role of IL-33 in host response to Candida albicans

Dual function of fungi-derived cytokines in inflammatory bowel diseases: protection or inflammation

Inflammatory bowel disease (IBD) is an immune-mediated inflammatory condition involving both the innate and adaptive immune systems. Recently, the role of intestinal fungal flora and their downstream immune pathways has been highlighted in the pathogenesis of IBD. Cytokines as primary immune mediators require a delicate balance for maintaining intestinal homeostasis. Although most cytokines have a predictable role in either amplifying or attenuating inflammation in IBD, a few cytokines have shown a dual function in the inflammatory state of the intestine. Some of these dual-faced cytokines are also involved in mucosal anti-microbial defense pathways, particularly against intestinal fungal residents. Here, we reviewed the role of these cytokines in IBD pathogenesis to achieve a better understanding of the fungal interactions in the development of IBD.

Deletion of IL-33R attenuates VEGF expression and enhances necrosis in mammary carcinoma

Interleukin-33 (IL-33)/IL-33 receptor (IL-33R, ST2) signaling pathway promotes mammary cancer growth and metastasis by inhibiting anti-tumor immunity. However, the role of IL-33/IL-33R axis in neoangiogenesis and tumor necrosis is not elucidated. Therefore, the aim of this study was to investigate the role of IL-33/IL-33R axis in mammary tumor necrosis. Deletion of IL-33R (ST2) gene in BALB/c mice enhanced tumor necrosis and attenuated tumor growth in 4T1 breast cancer model, which was associated with markedly decreased expression of vascular endothelial growth factor (VEGF) and IL-33 in mammary tumor cells. We next analyzed IL-33, IL-33R and VEGF expression and microvascular density (MVD) in breast tumors from 40 female patients with absent or present tumor necrosis. We found significantly higher expression of IL-33, IL-33R and VEGF in breast cancer tissues with absent tumor necrosis. Both, IL-33 and IL-33R expression correlated with VEGF expression in tumor cells. Further, VEGF expression positively correlated with MVD in perinecrotic zone. Taking together, our data indicate that IL-33/IL-33R pathway is critically involved in mammary tumor growth by facilitating expression of pro-angiogenic VEGF in tumor cells and attenuating tumor necrosis. These data add an unidentified mechanism by which IL-33/IL-33R axis facilitates tumor growth.

IL-33/ST2 involves the immunopathology of ocular toxoplasmosis in murine model

Ocular toxoplasmosis (OT) is the major cause of infective uveitis. Since the eye is a special organ protected by immune privilege, its immune response is different from general organs with Toxoplasma gondii infection. Here, we used Kunming outbred mice to establish OT by intravitreal injection of T. gondii RH strain tachyzoites, IL-33 expression in the eyes was localized by immunostaining, the levels of interleukin (IL)-33 and ST2 (IL-33 receptor) and T-helper (Th)1 and Th2-associated cytokines in the eye and cervical lymph nodes (CLNs) of infected mice were measured, and their correlations were analyzed. Our results showed that the pathologies of the eye and CLN tissues and the IL-33 positive cells in the eye tissues of ocular T. gondii-infected mice were all increased at days 2, 6, and 9 postinfection (p.i.), accompanied with significantly increased transcript levels of IL-33, ST2, IL-1β, IFN-γ, IL-12p40, IL-10, and IL-13 in both the eyes and CLNs, and increased IL-4 expressions in the eyes of T. gondii-infected mice. There were significant correlations between the levels of IFN-γ and ST2, IL-4 and ST2, and IL-13 and ST2 in the eye tissues (P < 0.001), significant correlations between the levels of IFN-γ and ST2 (P < 0.001) as well as between IL-13 and ST2 (P < 0.05) in the CLNs, and significant correlations between the levels of IL-1β and IL-33 in the eyes (P < 0.05) and between IL-1β and IL-33/ST2 in the CLNs (P < 0.001 and P < 0.01, respectively). Our data indicated that IL-33/ST2 may involve the regulation of ocular immunopathology induced by T. gondii infection.