PI3Kgamma is the dominant isoform involved in migratory responses of human T lymphocytes: effects of ex vivo maintenance and limitations of non-viral delivery of siRNA
| Autor: | Richard V. Parry, Emma Hickman, Stephen G. Ward, Laura D. Smith, John Westwick |
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| Rok vydání: | 2007 |
| Předmět: |
Gene isoform
Time Factors T-Lymphocytes Cell Culture Techniques Biology Transfection TCIRG1 Phosphatidylinositol 3-Kinases Cytotoxic T cell Class Ib Phosphatidylinositol 3-Kinase Humans RNA Messenger Phosphorylation RNA Small Interfering Protein kinase B Protein Kinase Inhibitors PI3K/AKT/mTOR pathway Cells Cultured Phosphoinositide-3 Kinase Inhibitors Dose-Response Relationship Drug Gene targeting Cell migration Cell Biology Chemokine CXCL12 Cell biology Isoenzymes Chemotaxis Leukocyte RNA Interference Proto-Oncogene Proteins c-akt Ex vivo |
| Zdroj: | Cellular signalling. 19(12) |
| ISSN: | 0898-6568 |
| Popis: | Use of mice in which individual PI3K isoforms have been deleted or mutated by gene targeting, has determined that PI3Kgamma provides a key migratory signal for T lymphocyte migration. Since PI3Kgamma can be a dispensable signal for directional migration of human T cells, we have adopted a pharmacological and siRNA strategy to assess the contribution of individual PI3K isoforms to chemokine-stimulated migration of human T cells. The broad spectrum PI3K isoform inhibitor Ly294002 inhibits CXCL12-stimulated migration of freshly isolated T lymphocytes. Use of second generation inhibitors that can discriminate between individual PI3K isoforms, revealed that PI3Kgamma was the major contributor to CXCL12-induced migration and PI3K/Akt signaling (as assessed by S6 phosphorylation). Non-viral delivery of siRNA targeting class I (PI3Kgamma), class II (PI3KC2alpha and PI3KC2beta) and class III PI3Ks, followed by 3 days ex vivo culture, reduces the levels of isoform mRNA, but is insufficient to impact on cell migration responses. However, ex vivo maintenance of T cells alone, independently of siRNA treatment, resulted in the migratory response of T cells toward CXCL12 becoming insensitive to Ly294002. Remarkably, random migration remains sensitive to Ly294002. This study therefore, highlights that the migratory response of freshly isolated human T cells is dependent on PI3K signals that are provided predominantly by PI3Kgamma. However, the role of PI3K in cell migration is context-dependent and diminishes during ex vivo maintenance. |
| Databáze: | OpenAIRE |
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