title: Axl signaling induces development of natural killer cells in vitro and in vivo.
abstract: Natural killer (NK) cells have been well known to play a critical role in innate immunity, but they are also capable of regulating adaptive immunity through the induction of T cell-mediated memory response and B cell-mediated autoimmune response. NK cells are differentiated from hematopoietic stem cells (HSCs) in the bone marrow (BM), and a series of surface molecules are expressed on NK cells in a differentiation stage-specific manner. Axl receptor tyrosine kinase is originally identified as homeostatic regulators for antigen-presenting cells, and its ligand, growth-arrest-specific gene 6 (Gas6), has been reported to promote cell survival, proliferation, and migration, but their regulatory role in the development and effector function of NK cells is not yet fully understood. In this study, to investigate whether Axl is required for the regulation of NK cell development, the expression of mature NK (mNK) cell-specific receptors and NK cell-associated genes was analyzed in the differentiated HSCs-derived NK cells in vitro and the NK cells harvested from Axl-/-mice. We found that agonistic anti-Axl antibody or recombinant Gas6 specifically upregulated the expression of mNK cell-specific receptors, such as LY49A, Ly49G2, Ly49C/F/I, NKG2A/C/E (1.5- to 3.5-fold increase), and NK cell-associated genes, such as IL-2Rβ (2.3- or 2.4-fold increase), Perforin (4.1- or 2.1-fold increase), IL-15Rα (2.14- or 2.04-fold increase), and IFN-γ (3.3- or 2.8-fold increase) compared to each isotype control, whereas it was abrogated by treatment of Axl-Ig. Anti-Axl antibody or rGas6 also induced a 2.5- or 1.9-fold increase in the proliferation of developing NK cells compared to each control, respectively. mNK cell populations expressing mNK cell-specific receptors were reduced about twofold in NK cells differentiated from HSCs of Axl-/-mice compared with those of wild-type mice. Furthermore, the triggering of Axl signaling by agonistic anti-Axl antibody promoted the cytolytic activity (1.5- to 1.9-fold increase) against target tumor cells. In B16F10 melanoma-bearing mice, the number of metastatic colonies was decreased by 83 % by the administration of mNK cells treated with anti-Axl antibody compared to control Ig. These data suggest that Axl plays an essential role in the regulation of NK cell development as well as NK effector function.
authors.affiliation: Internal Medicine, University of Iowa and VA Medical Center, Iowa City, IA, 52246, USA.
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Kim
authors.affiliation: Advanced Radiation Technology Institute (ARTI), Korea Atomic Energy Institute (KAERI), 29 Geumgu-gil, Jeongeup-si, Jeollabuk-do, 580-185, South Korea.
authors.forename: Eun-Hee
authors.initials: EH
authors.lastname: Lee
authors.affiliation: Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Cheombok-ro 80, Dong-gu, Daegu, 41061, South Korea.
authors.forename: Hwa-Yeon
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Department of Nursing, Nambu University, 23 Chumdan Jungang-ro, Gwangsan-gu, Gwangju, 506-706, South Korea.
authors.forename: Ha-Rim
authors.initials: HR
authors.lastname: Choi
authors.affiliation: School of Biological Sciences and Technology, Chonnam National University, 300 Yongbong-dong, Bukgu, Gwangju, 500-757, Republic of Korea.
authors.forename: Kon-Young
authors.initials: KY
authors.lastname: Ji
authors.affiliation: School of Biological Sciences and Technology, Chonnam National University, 300 Yongbong-dong, Bukgu, Gwangju, 500-757, Republic of Korea.
authors.forename: Su-Man
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Division of Applied Life Science, PMBBRC, Gyeongsang National University, Jinju, 660-701, South Korea.
authors.forename: Kwang Dong
authors.initials: KD
authors.lastname: Kim
authors.affiliation: School of Biological Sciences and Technology, Chonnam National University, 300 Yongbong-dong, Bukgu, Gwangju, 500-757, Republic of Korea. kanghs@jnu.ac.kr.
authors.forename: Hyung-Sik
authors.initials: HS
authors.lastname: Kang
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D049109:Cell Proliferation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000201:enzymology; D007694:Killer Cells, Natural / Q000166:cytology* / Q000378:metabolism*; D008545:Melanoma / Q000276:immunology / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000172:deficiency / Q000378:metabolism*; D015398:Signal Transduction; D000094963:Axl Receptor Tyrosine Kinase
chemical_list: D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases; D000094963:Axl Receptor Tyrosine Kinase; C000722290:AXL receptor tyrosine kinase, mouse
keywords: Axl receptor tyrosine kinase; Gas6; Hematopoietic stem cells; Natural killer cell; mNK; pNK