Differential IL-12 signaling induces human natural killer cell activating receptor-mediated ligand-specific expansion

Abstract

IL-12 is an essential cytokine involved in the generation of memory or memory-like NK cells. Mouse cytomegalovirus infection triggers NK receptor-induced, ligand-specific IL-12–dependent NK cell expansion, yet specific IL-12 stimulation ex vivo leading to NK cell proliferation and expansion is not established. Here, we show that IL-12 alone can sustain human primary NK cell survival without providing IL-2 or IL-15 but was insufficient to promote human NK cell proliferation. IL-12 signaling analysis revealed STAT5 phosphorylation and weak mTOR activation, which was enhanced by activating NK receptor upregulation and crosslinking leading to STAT5-dependent, rapamycin-sensitive, or TGFβ-sensitive NK cell IL-12–dependent expansion, independently of IL-12 receptor upregulation. Prolonged IL-2 culture did not impair IL-12–dependent ligand-specific NK cell expansion. These findings demonstrate that activating NK receptor stimulation promotes differential IL-12 signaling, leading to human NK cell expansion, and suggest adopting strategies to provide IL-12 signaling in vivo for ligand-specific IL-2–primed NK cell–based therapies.

Diminished cell proliferation promotes natural killer cell adaptive-like phenotype by limiting FcεRIγ expression

“…We further showed that TGFβ or IFNα stimulation suppressed FcRγ upregulation independently of mTOR or FOXO1 activity ( Viel et al, 2016 ; Platanias, 2005 ). This shows that besides mTOR activation and FOXO1 suppression, other signaling pathways, such as Smad signaling ( Viel et al, 2016 ) or STAT1 signaling ( Platanias, 2005 ), which are reported to inhibit NK cell proliferation, suppress FcRγ expression ( Liu et al, 2020 ; Krämer et al, 2021 ; Witkowski et al, 2021 ; Shemesh et al, 2022 ). In line with these results, we showed that the increase in mature NK cells with an adaptive-like phenotype during COVID-19 infection is associated with increased TGFβ and IFNα levels and increased disease severity.…”

CD3ζ adaptor structure determines functional differences between human and mouse CD16 Fc-gamma receptor signaling in natural killer cells

“…We further showed that TGFβ or IFNα stimulation suppressed FcRγ upregulation independently of mTOR or FOXO1 activity (Viel et al, 2016;Platanias, 2005). This shows that besides mTOR activation and FOXO1 suppression, other signaling pathways, such as Smad signaling (Viel et al, 2016) or STAT1 signaling (Platanias, 2005), which are reported to inhibit NK cell proliferation, suppress FcRγ expression (Liu et al, 2020;Krämer et al, 2021;Witkowski et al, 2021;Shemesh et al, 2022). In line with these results, we showed that the increase in mature NK cells with an adaptive-like phenotype during COVID-19 infection is associated with increased TGFβ and IFNα levels and increased disease severity.…”

“…NK cell proliferation or expansion is regulated by IL-2, IL-15, and IL-12 (Wang and Zhao, 2021;Wiedemann et al, 2020;Shemesh et al, 2022), by the phosphorylation of STAT5 (pSTAT5), STAT4 (pSTAT4), and other STATs directly or indirectly, and by the activation of mammalian target of rapamycin (mTOR) complexes (Marçais et al, 2014;Anton et al, 2015;Anton et al, 2020). Activation of the mTOR complex-1 (mTORC1) leads to ribosomal protein S6 phosphorylation at position S235/236 (pS6S235/236) and regulates cap-dependent protein translation and cell cycle progression (Marçais et al, 2014).…”

“…The mTOR complex-2 (mTORC2) phosphorylates AKT at position S473 (pAKTS473), which inhibits FOXO1 activity, a suppressor of cell cycle progression (Wang et al, 2018;Calnan and Brunet, 2008). TGFβ or IFNα can diminish NK cell proliferation by various signaling pathways with or without inhibition of mTOR activity (Platanias, 2005;Viel et al, 2016;Gartel and Tyner, 2002;Shemesh et al, 2022).…”

Focusing on NK cells and ADCC: A promising immunotherapy approach in targeted therapy for HER2-positive breast cancer

“…Fujii R observed that the IL-15SA/IL-15RA complex can act as an inhibitor to block the inhibitory effects of TGF-β on the NK cell activation markers CD226, NKG2D, and NKp30 in breast, lung, and prostate cancers ( 87 ). IL-12 is an essential cytokine involved in the generation of memory-like NK cells, and IL-12 alone can sustain human primary NK cell survival without providing IL-2 or IL-15 but is insufficient to promote human NK cell proliferation ( 88 ). NK cells in breast tumors express high levels of NKG2A and low levels of NKp46, perforin, and granzyme B.…”