Intrinsic RIG-I restrains STAT5 activation to modulate antitumor activity of CD8+ T cells
Xinyi Jiang, … , Jiang Zhu, Hui Yang
Xinyi Jiang, … , Jiang Zhu, Hui Yang
Published March 16, 2023
Citation Information: J Clin Invest. 2023;133(9):e160790. https://doi.org/10.1172/JCI160790.
View: Text | PDF
Research Article Immunology Oncology

Intrinsic RIG-I restrains STAT5 activation to modulate antitumor activity of CD8+ T cells

Abstract

Antitumor activity of CD8+ T cells is potentially restrained by a variety of negative regulatory pathways that are triggered in the tumor microenvironment, yet, the exact mechanisms remain incompletely defined. Here, we report that intrinsic RIG-I in CD8+ T cells represents such a factor, as evidenced by observations that the tumor-restricting effect of endogenous or adoptively transferred CD8+ T cells was enhanced by intrinsic Rig-I deficiency or inhibition, with the increased accumulation, survival, and cytotoxicity of tumor-infiltrating CD8+ T cells. Mechanistically, T cell activation–induced RIG-I upregulation restrained STAT5 activation via competitive sequestering of HSP90. In accordance with this, the frequency of RIG-I+ tumor-infiltrating CD8+ T cells in human colon cancer positively correlated with attenuated survival and effector signatures of CD8+ T cells as well as poor prognosis. Collectively, these results implicate RIG-I as a potentially druggable factor for improving CD8+ T cell–based tumor immunotherapy.

Authors

Xinyi Jiang, Jian Lin, Chengfang Shangguan, Xiaoyao Wang, Bin Xiang, Juan Chen, Hezhou Guo, Wu Zhang, Jun Zhang, Yan Shi, Jiang Zhu, Hui Yang

×

Figure 7

RIG-I restrains CD8+ T cell survival and cytotoxicity by dampening HSP90-mediated protective effect on STAT5.

Options: View larger image (or click on image) Download as PowerPoint
RIG-I restrains CD8+ T cell survival and cytotoxicity by dampening HSP90...
(A) Indicated protein levels of splenic naive CD8+ T cells after 48 hours anti-CD3/CD28 stimulation were analyzed by Western blotting. (B) GSEA of RNA-Seq (same as Figure 6, D–G) comparing in vitro activated CD8+ T cells as indicated are shown. (C) Empirical cumulative distribution function for change in expression of all genes (black) expressed in in vitro activated Rig-I–/– CD8+ T cells (change relative to that in Rig-I+/+ CD8+ T cells) and for subsets of genes upregulated (red) or downregulated (blue) by overexpression of constitutively active STAT5 in CD8+ T cells. (D and E) Splenic naive CD8+ T cells were stimulated by anti-CD3/CD28 and STAT5-IN-1 (10 μM) for 2 days and analyzed by flow cytometry. (F and G) Cell lysates of in vitro stimulated CD8+ T cells were immunoprecipitated with dynabeads-coupled control IgG or RIG-I antibody (F). Cell lysates of naive Rig-I+/+ or Rig-I–/– CD8+ T cells stimulated with anti-CD3/CD28 for 2 days were immunoprecipitated with dynabeads-coupled control IgG or STAT5 antibody (G). The precipitates were then probed with indicated antibodies. (H) Lysates of 293T cells cotransfected with indicated plasmids were immunoprecipitated with HA antibody and analyzed by immunoblot with indicated antibodies. (I) Indicated protein levels of MC38 tumor-infiltrating CD45+CD8+ T cells were analyzed by Western blotting. (J) Mice s.c. inoculated with MC38 cells were treated with STAT5-IN-1. Schematic diagram and tumor growth curve are shown (n = 5 per group). Data are representative of at least 2 independent experiments and expressed as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, by 1-way ANOVA (D and E) or 2-way ANOVA (J). The same batch of samples were run contemporaneously in different gels for A and I.