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Koutník J, Leitges M, Siegmund K. T cell-intrinsic protein kinase D3 is dispensable for the cells' activation. Front Immunol 2022; 13:1049033. [PMID: 36466811 PMCID: PMC9713823 DOI: 10.3389/fimmu.2022.1049033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/24/2022] [Indexed: 07/21/2023] Open
Abstract
Protein kinases D (PKDs) are implicated in T cell receptor (TCR) signaling. Of the two T cell-expressed isoforms PKD2 and PKD3, however, only the former one is rather well understood in this immune cell type. Recently, we have observed a putative hyper-phenotype of T cells from conventional PKD3-knockout mice, which we explained as a secondary effect due to a skewed T cell compartment from naïve towards effector/memory T cells already under steady state conditions. Nonetheless, to this end it is not clear whether these aberrations are mediated by a T cell-intrinsic or -extrinsic function of PKD3. To address this question, we have investigated mice lacking PKD3 specifically in the T cell compartment. We could show that T cells from CD4-Cre-driven conditional knockout mice did not phenocopy the ones from conventional PKD3-knockout mice. In brief, no skewing in the T cell compartment of peripheral lymphoid organs, no hyper-activation upon stimulation in vitro or in vivo as well as no aberrations in follicular helper T cells (TFH) upon immunization were observed. Hence, although PKD3 is strongly regulated upon TCR stimulation, in T cells this kinase seems to be dispensable for their activation. The described skewing in the T cell compartment of conventional PKD3-deficient mice seems to be mediated by T cell-extrinsic mechanisms, thus once more emphasizing the importance of cell type-specific mouse models.
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Affiliation(s)
- Jiří Koutník
- Institute of Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael Leitges
- Division of BioMedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Kerstin Siegmund
- Institute of Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria
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Koutník J, Neururer V, Gruber T, Peer S, Hermann-Kleiter N, Olson WJ, Labi V, Leitges M, Baier G, Siegmund K. Addressing the role of PKD3 in the T cell compartment with knockout mice. Cell Commun Signal 2022; 20:54. [PMID: 35440091 PMCID: PMC9020081 DOI: 10.1186/s12964-022-00864-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
Background The Protein kinase D3 (PKD3) has been implicated in signal transduction downstream of the T cell receptor (TCR). However, its role for the activation of primary T lymphocytes has not been elucidated so far. Methods Expression of PKD isoforms in primary murine T cells was determined by RT-PCR and SDS-Page. A germline PKD3-knockout mouse line was analyzed for its immune response to OVA/alum intraperitoneal immunization. Phenotyping of the T cell compartment ex vivo as well as upon stimulation in vitro was performed by flow cytometry. Additionally, cytokine expression was assessed by flow cytometry, RT-PCR and Luminex technology. Results PKD expression in T cells is modulated by TCR stimulation, leading to a rapid down-regulation on mRNA and on protein level. PKD3-deficient mice respond to immunization with enhanced T follicular helper cell generation. Furthermore, peripheral PKD3-deficient CD4+ T cells express more interleukin-2 than wild type CD4+ T cells upon TCR stimulation ex vivo. However, purified naïve CD4+ T cells do not differ in their phenotype upon differentiation in vitro from wild type T cells. Moreover, we observed a shift towards an effector/memory phenotype of splenic T cells at steady state, which might explain the contradictory results obtained with pan-T cells ex vivo and naïve-sorted T cells. Conclusion While PKD3-deficiency in vivo in mice leads to a skewing of the T cell compartment towards a more activated phenotype, this kinase seems to be dispensable for naïve CD4+ T cell differentiation in vitro. Video Abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00864-w.
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Affiliation(s)
- Jiří Koutník
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Verena Neururer
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria.,Apoptosis, Cancer, and Development Laboratory, Equipe labellisée 'La Ligue', LabEx DEVweCAN, Centre de Recherche en Cancérologie de Lyon, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Université de Lyon, Université Claude Bernard Lyon1, 69008, Lyon, France
| | - Thomas Gruber
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Sebastian Peer
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria
| | | | - William J Olson
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria.,Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
| | - Verena Labi
- Institute of Developmental Immunology, Medical University Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Michael Leitges
- Division of BioMedical Sciences, Faculty of Medicine, Craig L Dobbin Genetics Research Centre, Memorial University of Newfoundland Health Science Centre, 300 Prince Philip Drive, St. John's, NF, A1B 3V6, Canada
| | - Gottfried Baier
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Kerstin Siegmund
- Institute of Cell Genetics, Medical University Innsbruck, Innsbruck, Austria.
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