Elsevier

Molecular Immunology

Volume 101, September 2018, Pages 80-85
Molecular Immunology

Galectin-7 promotes proliferation and Th1/2 cells polarization toward Th1 in activated CD4+ T cells by inhibiting The TGFβ/Smad3 pathway

https://doi.org/10.1016/j.molimm.2018.06.003Get rights and content

Highlights

  • Galectin-7 enhanced the proliferation of activated CD4+ T cells in a dose-dependent manner.

  • Galectin-7 treatment upregulated the ratio of Th1 cells in activated CD4+ T cells.

  • The mitogenic effects of Galectin-7 are associated with a proinflammatory microenvironment.

  • Galectin-7 promotes proliferation and Th1/2 cells polarization toward Th1 by inhibiting the TGFβ/Smad3 pathway.

Abstract

Galectin-7 (Gal-7) has been associated with cell proliferation and apoptosis. It is known that Gal-7 antagonises TGFβ-mediated effects in hepatocytes by interacting with Smad3. Previously, we have demonstrated that Gal-7 is related to CD4+ T cells responses; nevertheless, its effect and functional mechanism on CD4+ T cells responses remain unclear. The murine CD4+ T cells were respectively cultured with Gal-7, anti-CD3/CD28 mAbs, or with anti-CD3/CD28 mAbs & Gal-7. The effects of Gal-7 on proliferation and the phenotypic changes in CD4+ T cells were assessed by flow cytometry. The cytokines from CD4+ T cells were analysed by quantitative real-time PCR. Subcellular localisation and expression of Smad3 were determined by immunofluorescence staining and Western blot, respectively. Gal-7 enhanced the proliferation of activated CD4+ T cells in a dose- and β-galactoside-dependent manner. Additionally, Gal-7 treatment did not change the ratio of Th2 cells in activated CD4+ T cells, while it increased the ratio of Th1 cells. Gal-7 also induced activated CD4+ T cells to produce a higher level of IFN-γ and TNF-α and a lower level of IL-10. Moreover, Gal-7 treatment significantly accelerated nuclear export of Smad3 in activated CD4+ T cells. These results revealed a novel role of Gal-7 in promoting proliferation and Th1/2 cells polarization toward Th1 in activated CD4+ T cells by inhibiting the TGFβ/Smad3 pathway.

Introduction

Galectins (Gals) are a family of conserved β-galactoside-binding proteins that have been recognised as novel regulators of immune cells (Leffler et al., 2002; Liu and Rabinovich, 2005; Novak et al., 2014; Rabinovich et al., 2002). Galectin-7 (Gal-7) is preferentially expressed in stratified epithelia and in various types of cancer, and is associated with cell apoptosis and proliferation (Bernerd et al., 1999; Cao et al., 2003; Kuwabara et al., 2002; Madsen et al., 1995).

Our previous studies have revealed that Gal-7 expression increased significantly in cardiac allografts compared with cardiac isografts in mice. Additionally, the majority of Gal-7-positive cells in the allografts comprised infiltrating lymphocytes and vascular endothelial cells. Subsequently, we reported that the percentage of Gal-7-positive CD4+ T-cell is significantly higher in allograft group compared to isograft group (Luo et al., 2013). We have also identified increased Gal-7 expression in serum from renal allograft recipients compared with normal volunteers (Gao et al., 2009). In addition, Inagaki and colleagues have showed that Gal-7 as a transcriptional regulator antagonises TGFβ-mediated effects by interacting with Smad3 in hepatocytes (Inagaki et al., 2008). TGFβ is essential for attenuating CD4+ T-cell activation necessary to maintain immune homeostasis (Worthington et al., 2012). These findings suggest that Gal-7 is associated with the allograft rejection and CD4+ T-cell responses. However, the effects and functional mechanism of Gal-7 in the process of CD4+ T-cell response still remain unknown.

Rossi et al. (2008) have confirmed that Gal-7 binds to the glycosylation of TCR/CD3 complex on T-cell surface. The glycosylation differences may have an impact on T-cell proliferation and differentiation (Kjer-Nielsen et al., 2004). The TCR/CD3 complex is one of the important factors affecting the Th1 and Th2 cells immune responses (Mannie, 1997). Th1 cells induce IFN-γ production to inhibit tumor formation and regulate immune responses and inflammation. Th2 cells produce IL-4, thus mediating the activation of the allergy or humoral immune response. It has been found that the imbalance of Th1/Th2 responses may lead to a variety of immune diseases. The excessive amounts of IFN-γ have been associated with Th1-mediated immune disorders, such as allograft rejection and several autoimmune diseases (Murphy and Reiner, 2002).

To examine the role of Gal-7 protein in CD4+ T-cell responses, CD4+ T-cell proliferation and phenotypic changes of CD4+ T cells were analysed by flow cytometry to further investigate the role of Gal-7 in the Thl and Th2 cells responses. The cytokines of CD4+ T cells were examined by quantitative real-time PCR. To study the mechanism of Gal-7 in the process of T-cell response, subcellular localisation and expression of Smad3 were determined by immunofluorescence staining and Western blot analyses.

Section snippets

Mice

Male BALB/c (H-2d) mice were obtained from Vital River Laboratories, China. Animals were fed under controlled conditions. In addition, all animals were housed in an environment with temperature of 22 ± 1 °C, relative humidity of 50 ± 1% and a light/dark cycle of 12/12 h. Furthermore, all animal studies (including the mice euthanasia procedure) were done in compliance with the regulations and guidelines of Tongji Medical College institutional animal care and were conducted according to the

No cell proliferation of resting CD4+ T-lymphocytes was observed following the administration of Gal-7

We analysed the effects of Gal-7 on resting CD4+ T-cell proliferation. The CFSE-labelled CD4+ T cells were administered with PBS or different concentrations of Gal-7 for 5 days. Cellular suspensions were analysed to determine the level of CD4+ T-cell proliferation using flow cytometry. To sum up, no proliferation of CD4+ T-cell was observed in any group (Fig. 1, data not shown), which suggests that Gal-7 did not enhance the proliferation of resting CD4+ T-cell.

Gal-7 enhanced the proliferation of activated CD4+ T lymphocytes

The effects of Gal-7 on the

Discussion

Galectins exert important effects on the immune system by manipulating T-cell apoptosis and proliferation (Leffler et al., 2002; Liu and Rabinovich, 2005; Novak et al., 2014; Rabinovich et al., 2002). Gal-1 modulates Th1 and Th17 cells growth and apoptosis (Toscano et al., 2007), while Gal-2 promotes apoptosis in activated T cells (Sturm et al., 2004). Gal-9 has been shown to induce activated Th1 cells apoptosis (Zhu et al., 2005). Our group has revealed that Gal-9 can inhibit T-cell

Conflict of interest

The authors declare no conflict of interest.

Acknowledgment

This study was supported by National Natural Science Foundation of China (nos. 81500436, 81671582).

References (26)

  • Z. Cao et al.

    Galectin-7 as a potential mediator of corneal epithelial cell migration

    Arch. Ophthalmol.

    (2003)
  • Y. Gao et al.

    Characterization of acute renal allograft rejection by human serum proteomic analysis

    J. Huazhong Univ. Sci. Technol. Med. Sci.

    (2009)
  • L. Gorelik et al.

    Transforming growth factor-beta in T-cell biology

    Nat. Rev. Immunol.

    (2002)
  • Cited by (26)

    • Therapeutic potential of targeting galectins – A biomaterials-focused perspective

      2022, Biomaterials
      Citation Excerpt :

      The microbubbles were targeted by ultrasound and selectively inhibited gal-7 expression [209]. The lectin has been shown to play a pivotal role in cellular immune response triggering grafted tissue rejection through Th1/Th2 differentiation toward Th1 [210]. The cationic microbubbles were combined with ultrasound-targeted microbubble destruction to obtain local immunosuppression.

    • Aptamer-mediated drug delivery system for cardiovascular diseases

      2022, Combination Drug Delivery Approach as an Effective Therapy for Various Diseases
    • Emerging role of galectin family in inflammatory autoimmune diseases

      2021, Autoimmunity Reviews
      Citation Excerpt :

      As an important subfamily of galectins, addition of galectin-7 into Jurkat T cells inhibited the ratio of apoptotic Jurkat cells, and up-regulated IL-2, IFNβ expression [77]. This was confirmed in mice CD4+ T cells, where there was increased percentage of proliferating cells after incubation with galectin-7 and elevation of IFNγ, TNFα, decreased IL-10 expression [78]. Galectin-7 treatment up-regulated the ratio of CD4+IFNγ+ T cells, increased cytoplasmic Smad3 phosphorylation, indicating that galectin-7 may promote proliferation of Th1 cells by regulating Smad3 pathway and inhibit apoptosis of T cells [77,78].

    • Targeted galectin-7 inhibition with ultrasound microbubble targeted gene therapy as a sole therapy to prevent acute rejection following heart transplantation in a Rodent model

      2020, Biomaterials
      Citation Excerpt :

      Inhibition of this mediator had profound effects on the lymphocytic and vascular responses to allogenic heart transplantation, without the need for additional systemic immunosuppressive agents. Galectin-7 has been shown to be a primary mediator in the modulation of acute T-cell mediated rejection [3,26]. In the present AR model, UTMD of siGal-7 microbubbles (average size <500 nm) resulted in a protective effect against AR in the early post-transplantation period.

    View all citing articles on Scopus
    View full text