Project description:NK cells develop in the bone marrow and complete their maturation in peripheral organs, but the molecular events controlling maturation are incompletely understood. Utilizing an NK cell-specific miR-15/16 deficient genetic model (15aKO), we identified a critical role for miR-15/16 family microRNAs in the normal maturation of NK cells in vivo, with a specific reduction in mature CD11b+CD27- NK cells in multiple tissues. The mechanism responsible was a block in differentiation, since accelerated NK cell death was not evident, and earlier intermediates of NK cell maturation were expanded. Further, we identified Myb as a direct target of miR-15/16 in NK cells, with Myb expression increased in immature 15aKO NK cells. Following adoptive transfer, immature 15aKO NK cells exhibited defective maturation, which was rescued by ectopic miR-15/16 expression or Myb knockdown. Moreover, Myb overexpression resulted in defective NK cell maturation. Thus, miR-15/16 regulation of Myb controls the normal NK cell maturation program.
Project description:NK cells develop in the bone marrow and complete their maturation in peripheral organs, but the molecular events controlling maturation are incompletely understood. Utilizing an NK cell-specific miR-15/16 deficient genetic model (15aKO), we identified a critical role for miR-15/16 family microRNAs in the normal maturation of NK cells in vivo, with a specific reduction in mature CD11b+CD27- NK cells in multiple tissues. The mechanism responsible was a block in differentiation, since accelerated NK cell death was not evident, and earlier intermediates of NK cell maturation were expanded. Further, we identified Myb as a direct target of miR-15/16 in NK cells, with Myb expression increased in immature 15aKO NK cells. Following adoptive transfer, immature 15aKO NK cells exhibited defective maturation, which was rescued by ectopic miR-15/16 expression or Myb knockdown. Moreover, Myb overexpression resulted in defective NK cell maturation. Thus, miR-15/16 regulation of Myb controls the normal NK cell maturation program.
Project description:NK cells develop in the bone marrow and complete their maturation in peripheral organs, but the molecular events controlling maturation are incompletely understood. Utilizing an NK cell-specific miR-15/16 deficient genetic model (15aKO), we identified a critical role for miR-15/16 family microRNAs in the normal maturation of NK cells in vivo, with a specific reduction in mature CD11b+CD27- NK cells in multiple tissues. The mechanism responsible was a block in differentiation, since accelerated NK cell death was not evident, and earlier intermediates of NK cell maturation were expanded. Further, we identified Myb as a direct target of miR-15/16 in NK cells, with Myb expression increased in immature 15aKO NK cells. Following adoptive transfer, immature 15aKO NK cells exhibited defective maturation, which was rescued by ectopic miR-15/16 expression or Myb knockdown. Moreover, Myb overexpression resulted in defective NK cell maturation. Thus, miR-15/16 regulation of Myb controls the normal NK cell maturation program. KY-1 and KY-2 cell lines overexpressing c-Myb
Project description:NK cells develop in the bone marrow and complete their maturation in peripheral organs, but the molecular events controlling maturation are incompletely understood. Utilizing an NK cell-specific miR-15/16 deficient genetic model (15aKO), we identified a critical role for miR-15/16 family microRNAs in the normal maturation of NK cells in vivo, with a specific reduction in mature CD11b+CD27- NK cells in multiple tissues. The mechanism responsible was a block in differentiation, since accelerated NK cell death was not evident, and earlier intermediates of NK cell maturation were expanded. Further, we identified Myb as a direct target of miR-15/16 in NK cells, with Myb expression increased in immature 15aKO NK cells. Following adoptive transfer, immature 15aKO NK cells exhibited defective maturation, which was rescued by ectopic miR-15/16 expression or Myb knockdown. Moreover, Myb overexpression resulted in defective NK cell maturation. Thus, miR-15/16 regulation of Myb controls the normal NK cell maturation program. 3 technical replicates each of CD27+ 15a/16-1FKO NK cells, and CD27+ Ctrl NK cells
Project description:Interleukin-15 (IL-15) is essential for the development and maintenance of natural killer (NK) cells. IL-15 activates STAT5 proteins, which can form dimers or tetramers. We previously found that NK cell numbers are decreased in Stat5a-Stat5b tetramer-deficient double knockin (DKI) mice, but the mechanism was not investigated. Here we show that STAT5 dimers are sufficient for NK cell development, whereas STAT5 tetramers mediate NK cell maturation and the expression of maturation-associated genes. Unlike the defective proliferation of Stat5 DKI CD8+ T cells, Stat5 DKI NK cells have normal proliferation to IL-15 but are susceptible to death upon cytokine withdrawal, with lower Bcl2 and increased active caspases. These findings underscore the importance of STAT5 tetramers in maintaining NK cell homeostasis. Moreover, defective STAT5 tetramer formation could represent a cause of NK cell immunodeficiency, and interrupting STAT5 tetramer formation might serve to control NK leukaemia.