ADP-ribose/TRPM2-mediated Ca2+ signaling is essential for cytolytic degranulation and antitumor activity of natural killer cells

作者：Rah So Young; Kwak Jae Yong; Chung Yun Jo; Kim Uh Hyun^*

来源：Scientific Reports, 2015, 5(1): 9482.

DOI：10.1038/srep09482

Natural killer (NK) cells are essential for immunosurveillance against transformed cells. Transient receptor potential melastatin 2 (TRPM2) is a Ca2+-permeable cation channel gated by ADP-ribose (ADPR). However, the role of TRPM2-mediated Ca2+ signaling in the antitumor response of NK cells has not been explored. Here, we show that ADPR-mediated Ca2+ signaling is important for cytolytic granule polarization and degranulation but not involved in target cell recognition by NK cells. The key steps of this pathway are: 1) the activation of intracellular CD38 by protein kinase A following the interaction of the NK cell with a tumor cell results in the production of ADPR, 2) ADPR targets TRPM2 channels on cytolytic granules, and 3) TRPM2-mediated Ca2+ signaling induces cytolytic granule polarization and degranulation, resulting in antitumor activity. NK cells treated with 8-Br-ADPR, an ADPR antagonist, as well as NK cells from Cd38(-/-) mice showed reduced tumor-induced granule polarization, degranulation, granzyme B secretion, and cytotoxicity of NK cells. Furthermore, TRPM2-deficient NK cells showed an intrinsic defect in tumoricidal activity. These results highlight CD38, ADPR, and TRPM2 as key players in the specialized Ca2+ signaling system involved in the antitumor activity of NK cells.

• 出版日期2015-3-25