The role of TIM-containing molecules in airway disease and their potential as therapeutic targets

Blockage of Galectin-Receptor Interactions Attenuates Mouse Hepatic Pathology Induced by Toxoplasma gondii Infection

Toxoplasma gondii (T. gondii), one of the most important Apicomplexan protozoa, causes toxoplasmosis in human throughout the world. Galectin (Gal)-9 triggers a series of immune events via binding to its receptors, including T cell immunoglobulin and mucin-containing molecule 3, CD137, CD44, and protein disulfide isomerase. To examine the regulatory role of galectin-receptor interactions in anti-toxoplasmic activities, C57BL/6 mice were infected with T. gondii RH strain and intraperitoneally injected with alpha (α)-lactose to block the interactions of galectins and their receptors. Heatmaps showed upregulated values for Gal-9 and CD137 in the livers of T. gondii-infected mice and T. gondii-infected mice treated with α-lactose. Compared with T. gondii-infected mice, T. gondii-infected mice treated with α-lactose showed significantly increased survival rate, decreased tissue parasite burden, attenuated liver histopathology, increased mRNA expression levels of CD137, IFNγ, IL-4, and IL-10 in the liver, and increased Gal-9 mRNA expression level in the spleen. Correlation analysis showed that significant positive correlations existed between the mRNA expression levels of Gal-9 and CD137, Gal-9 and IFNγ, as well as between CD137 and IFNγ in the liver and spleen of T. gondii-infected mice; between CD137 and IFNγ in the liver of T. gondii-infected mice treated with α-lactose. In addition, blockage of galectin-receptor interactions showed enhanced M2 macrophage polarization in the liver of T. gondii-infected mice. Our data indicate that Gal-9-CD137 interaction may play an important role in T. gondii proliferation and liver inflammation in mice during acute T. gondii infection, through regulating T cell and macrophage immune responses.

Involvement of the Tim-3 Pathway in the Pathogenesis of Pre-Eclampsia

Current methods of early diagnosis and prevention of pre-eclampsia (PE) are limited; the only available definite treatment is the initiation of delivery and complete removal of the placenta. Inappropriate activation of the immune system is thought to play considerable roles in PE. T cell immunoglobulin mucin-3 (Tim-3) has been reported to regulate immune responses and play important roles in maternal-fetal tolerance during early pregnancy. In this study, we investigated the functional regulation of Tim-3 in the maternal-fetal crosstalk during 3rd-trimester healthy pregnancy and its possible role in the pathogenesis of PE. We found that Tim-3 expression on decidual immune cells was associated with production of anti-inflammatory cytokines. Tim-3 pathway blockade resulted in higher IFN-γ but lower IL-4 and IL-10 production. Using a tube formation assay between HTR8/SVneo cells and human umbilical vein endothelial cells, we found that Tim-3 pathway blockade inhibits tube formation and reversed by addition of recombinant IL-4 and/or IL-10. Pre-eclamptic patients showed reduced Tim-3 expression on both decidual and peripheral immune cells (especially on peripheral CD8⁺T cells). Therefore, we proposed that abnormal Tim-3 signal resulted in immunological imbalance at the maternal-fetal interface and may be involved in the progress of PE by affecting uterine spiral artery remodeling. Our study expanded the regulatory function of Tim-3 signaling pathway to the 3rd-trimester pregnancy and provided a new target for early warning and therapeutic strategies of PE.

The Antiviral Role of Galectins toward Influenza A Virus Infection-An Alternative Strategy for Influenza Therapy

Animal lectins are proteins with carbohydrate recognition activity. Galectins, the β-galactoside binding lectins, are expressed in various cells and have been reported to regulate several immunological and physiological responses. Recently, some galectins have been reported to regulate some viral infections, including influenza A virus (IAV); however, the mechanism is still not fully understood. Thus, we aim to review systemically the roles of galectins in their antiviral functions against IAVs. The PRISMA guidelines were used to select the eligible articles. Results indicated that only Galectin-1, Galectin-3, and Galectin-9 were reported to play a regulatory role in IAV infection. These regulatory effects occur extracellularly, through their carbohydrate recognition domain (CRD) interacting with glycans expressed on the virus surface, as well as endogenously, in a cell-cell interaction manner. The inhibition effects induced by galectins on IAV infection were through blocking virus-host receptors interaction, activation of NLRP-3 inflammasome, augment expression of antiviral genes and related cytokines, as well as stimulation of Tim-3 related signaling to enhance virus-specific T cells and humoral immune response. Combined, this study concludes that currently, only three galectins have reported antiviral capabilities against IAV infection, thereby having the potential to be applied as an alternative anti-influenza therapeutic strategy.

Regulatory T Cells in Respiratory Health and Diseases

Respiratory diseases compromise the health of millions of people all over the world and are strongly linked to the immune dysfunction. CD4+FOXP3+ T regulatory cells, also known as Tregs, have a central role maintaining tissue homeostasis during immune responses. Their activity and clinical impact have been widely studied in different clinical conditions including autoimmune diseases, inflammatory conditions, and cancer, amongst others. Tregs express transcription factor forkhead box P3 (FOXP3), which allows regulation of the immune response through anti-inflammatory cytokines such as IL-10 or transforming growth factor beta (TGF-β) and direct cell-to-cell interaction. Maintenance of immune tolerance is achieved via modulation of effector CD4+ T helper 1, 2 or 17 (Th1, Th2, Th17) cells by Tregs. This review highlights the recent progress in the understanding of Tregs in different disorders of the respiratory system.

Expression and polymorphisms of T cell immunoglobulin domain and mucin domain protein-1 in thymoma with or without myasthenia gravis

The present study aimed to investigate the expression and association of the single-nucleotide polymorphism (SNP) -1637A/G in the promoter region of the T cell immunoglobulin domain and mucin domain protein-1 (Tim-1) gene in patients diagnosed with thymoma with or without myasthenia gravis (MG). The expression of Tim-1 was detected using the streptavidin peroxidase immunohistochemical staining method on tissues obtained from thymoma patients with (n=58) and without (n=62) MG. The Tim-1 gene -1637A/G polymorphism was detected using the single allele-specific primer polymerase chain reaction. The positive rate of Tim-1 expression in thymoma patients with MG was 62.1% (32/58), which was significantly higher compared with that in thymoma patients without MG (33.9%, 21/62) (P=0.002). The genotype frequencies of GG, GA and AA in the -1637A/G polymorphism were 0.7931, 0.2069 and 0, respectively, in thymoma patients with MG, and 0.6129, 0.3871 and 0, respectively, in thymoma patients without MG. A significant difference in the genotypes between the thymoma patients with MG and those without MG was found (P=0.031). In addition, a significant difference in allele frequencies between thymoma patients with MG and those without MG (P=0.024) was observed. The high expression of Tim-1 in thymoma tissues may play an important role in the development of thymoma with MG. The -1637A/G polymorphism site of the promoter region in Tim-1 may be associated with thymoma with MG. These findings provide a basis for further genetic research of thymoma with MG.