Cytosolic protein translation regulates cell asymmetry and function in early TCR activation of human CD8+ T lymphocytes

Front Immunol. 2024 Jul 24:15:1411957. doi: 10.3389/fimmu.2024.1411957. eCollection 2024.

Abstract

Introduction: CD8+ cytotoxic T lymphocytes (CTLs) are highly effective in defending against viral infections and tumours. They are activated through the recognition of peptide-MHC-I complex by the T-cell receptor (TCR) and co-stimulation. This cognate interaction promotes the organisation of intimate cell-cell connections that involve cytoskeleton rearrangement to enable effector function and clearance of the target cell. This is key for the asymmetric transport and mobilisation of lytic granules to the cell-cell contact, promoting directed secretion of lytic mediators such as granzymes and perforin. Mitochondria play a role in regulating CTL function by controlling processes such as calcium flux, providing the necessary energy through oxidative phosphorylation, and its own protein translation on 70S ribosomes. However, the effect of acute inhibition of cytosolic translation in the rapid response after TCR has not been studied in mature CTLs.

Methods: Here, we investigated the importance of cytosolic protein synthesis in human CTLs after early TCR activation and CD28 co-stimulation for the dynamic reorganisation of the cytoskeleton, mitochondria, and lytic granules through short-term chemical inhibition of 80S ribosomes by cycloheximide and 80S and 70S by puromycin.

Results: We observed that eukaryotic ribosome function is required to allow proper asymmetric reorganisation of the tubulin cytoskeleton and mitochondria and mTOR pathway activation early upon TCR activation in human primary CTLs.

Discussion: Cytosolic protein translation is required to increase glucose metabolism and degranulation capacity upon TCR activation and thus to regulate the full effector function of human CTLs.

Keywords: T cell activation; cell asymmetry; cytoskeleton; cytotoxic CD8+ T lymphocytes; immunological synapse; metabolism; mitochondria; protein translation.

MeSH terms

  • CD8-Positive T-Lymphocytes* / immunology
  • CD8-Positive T-Lymphocytes* / metabolism
  • Cytoskeleton / metabolism
  • Cytosol* / metabolism
  • Humans
  • Lymphocyte Activation* / immunology
  • Mitochondria* / immunology
  • Mitochondria* / metabolism
  • Protein Biosynthesis*
  • Receptors, Antigen, T-Cell* / immunology
  • Receptors, Antigen, T-Cell* / metabolism
  • Ribosomes / metabolism
  • Signal Transduction
  • T-Lymphocytes, Cytotoxic / immunology
  • T-Lymphocytes, Cytotoxic / metabolism
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • Receptors, Antigen, T-Cell
  • TOR Serine-Threonine Kinases

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by grants from the Madrid Regional Government (S2022/BMD-7209-INTEGRAMUNE-CM) to NM-C and PM, Obra Social Fundación la Caixa (LCF/PR/HR23/52430018) to NM-C, and grants funded by MCIN/AEI/10.13039/501100011033 (PID2022–141895OB-I00 to NM-C, and PID2021‐127899OB‐I00 and CNS2023–144841 to EM-G). EM-G lab was supported by the Ramón y Cajal Program (RYC2018–024374-I), La Caixa Banking Foundation ETI-CureHIV (HR20–00218), and infectious diseases CIBER from ISCIII (CIBERINFECC). PM-F lab is funded by MCIN-ISCIII-Fondo de Investigación Sanitaria (PI22/01759) co-funded by the ERDF and (PMPTA22/00090-BIOCARDIOTOX) co-funded by the NextGEN. AA lab is funded by INMUNOVACTER REACT-EU grant from the Madrid Regional Government and by Fondo de Investigación Sanitaria del ISCIII, co-funded by the Fondo Europeo de Desarrollo Regional (FEDER) (FIS PI22/01542). AG-M is supported by an Investigo Grant (2022‐C23.I01.P03.S0020000003) by SEPE (Fondos de Resiliencia), Gobierno de España. IT is supported by an FPI-UAM fellowship by Universidad Autónoma de Madrid. CS is supported by a “Garantía Juvenil” grant from the Madrid Regional Government (PEJ-2021-TL/BMD-21204). CP is supported by the Spanish Ministry of Science and Innovation (CPP2021–008385). ML-P is an FPI fellowship (PRE2021–097478) from the Spanish Ministry of Science and Innovation. PM-F is supported by a Rio-Hortega grant (CM22/00076) from the Ministry of Economy and Competitiveness (ISCIII) and co-funded by the European Regional Development Fund (ERDF) “A way to make Europe”. SR is supported by a Sara Borrell fellowship from ISCIII. The Centro Nacional de Investigaciones Cardiovasculares (CNIC) is supported by the Instituto de Salud Carlos III (ISCIII), the Ministry of Science and Innovation (MCIN), and the Fundación Pro CNIC and is a Severo Ochoa Centre of Excellence (CEX2020–001041-S) funded by MICIN/AEI/10.13039/501100011033). Funding agencies have not intervened in the design of the studies, with no copyright over the study.