Regulation von Effektor- und Gedächtnis- T-Zellantworten im peripheren Gewebe
Zusammenfassung der Projektergebnisse
T cells provide efficient immune protection from infectious diseases and cancer but can also drive pathology associated with autoimmunity and chronic inflammation. Thus, their therapeutic manipulation has a great potential in preventing and treating a broad spectrum of diseases. One such example are the recently introduced cancer immunotherapies that have revolutionized the treatment of late stage cancer patients. Attempts at further improving immunotherapies will require a detailed understanding of the molecular pathways underpinning the generation and maintenance of T cell responses throughout the body. My particular focus lies on so-called tissue resident memory T cells (TRM), which permanently reside in peripheral tissues after infection or inflammation. TRM from different tissues share a transcriptional signature that clearly distinguishes them from T cells found in blood. Some of these genes are promising targets for the modulation of TRM responses with future therapies. To address their functional relevance, I have established a gene-editing platform that allows for conditional over-expression or ablation of target genes via CRISPR/Cas in primary murine T cells. I have overcome a number of major obstacles, such as poor transduction efficiency and T cell survival that thus far have limited the use of gene editing systems in the T cell field. My experiments demonstrate that CRISPR/Cas is functional in primary T cells. Furthermore, my data provide first evidence for the suitability of the overexpression and ablation systems to study TRM function. I am currently following up initial findings showing that KLRG1 overexpression inhibits TRM formation. The novel platform provides unprecedented opportunities for the identification and in-depth investigation of molecular pathways that can be targeted in future therapies. In a second project, I investigated the role of the Protein tyrosine phosphatase non-receptor type 2 (ptpn2) in TRM formation and function in a model of Herpes simplex virus skin infection, using conventional transgenic T cells. Ptpn2 has previously been shown to regulate T cell receptor and cytokine receptor signalling, making it a potential candidate gene for T cell regulation. I observed a profound defect in ptpn2-deficient T cells to form a stable TRM population in vivo. Related to this, I found a relative reduction of KLRG1- TRM precursors after priming. Normalising for KLRG1- cells by FACS or in vitro activation of cells lead to similar TRM numbers. RNAseq and functional assays are ongoing and will reveal, whether ptpn2, besides promoting TRM development might also regulate (potentially detrimental) effector functions. Taken together, during the DFG funding period I have investigated the role of ptpn2 in TRM biology with conventional transgenic T cells. Furthermore, I have established a cutting-edge platform for gene-editing in primary murine T cells. This technology will enable me to study TRM biology in unprecedented detail and breadth, with the aim to develop novel disease intervention strategies.
