Stéphanie Dogniaux

// Asma Beldi-Ferchiou 1, 2, 11 , Marion Lambert 1, 2 , Stéphanie Dogniaux 3 , Frédéric Vély 4, 5 , Eric Vivier 4, 5 , Daniel Olive 6 , Stéphanie Dupuy 1 , Frank Levasseur 1 , David Zucman 7 , Céleste Lebbé 8 , Damien Sène 1, 2, 9 , Claire Hivroz 4 , Sophie Caillat-Zucman 1, 2, 10 1 Institut National de Recherche Médicale (INSERM) UMR1149, Centre de Recherche Sur l’Inflammation, Équipe Immunité Innée Chez l’enfant, Hôpital Robert Debré, Paris, France 2 Université Paris Diderot, Sorbonne Paris Cité, Paris, France 3 Institut Curie, Centre de Recherche, PSL Research University, INSERM U932 Immunité et Cancer, Paris, France 4 Centre d’Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, INSERM U1104, CNRS UMR7280, Marseille, France 5 Immunologie, Hôpital de la Conception, Assistance Publique- Hôpitaux de Marseille, Marseille, France 6 Centre de Cancérologie de Marseille, INSERM U1068, Equipe Immunité et Cancer, Institut Paoli-Calmettes, Aix-Marseille Université, CNRS, UMR7258, Marseille, France 7 Hôpital Foch, Service de Médecine Interne, Suresnes, France 8 Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Saint-Louis, Département de Dermatologie, INSERM U976, Université Paris Diderot, Paris, France 9 Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Lariboisière, Département de Médecine Interne, Paris, France 10 Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Saint-Louis, Laboratoire d’Immunologie, Paris, France 11 Present address: Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Henri Mondor, Laboratoire d’Immunologie, Créteil, France Correspondence to: Sophie Caillat-Zucman, email: sophie.caillat@inserm.fr Keywords: NK cells, Kaposi sarcoma, PD-1, immune checkpoint, tumor escape Received: March 31, 2016      Accepted: September 13, 2016      Published: September 20, 2016 ABSTRACT Programmed Death-1 (PD-1), an inhibitory receptor expressed by activated lymphocytes, is involved in regulating T- and B-cell responses. PD-1 and its ligands are exploited by a variety of cancers to facilitate tumor escape through PD-1-mediated functional exhaustion of effector T cells. Here, we report that PD-1 is upregulated on Natural Killer (NK) cells from patients with Kaposi sarcoma (KS). PD-1 was expressed in a sub-population of activated, mature CD56 dim CD16 pos NK cells with otherwise normal expression of NK surface receptors. PD-1 pos NK cells from KS patients were hyporesponsive ex vivo following direct triggering of NKp30, NKp46 or CD16 activating receptors, or short stimulation with NK cell targets. PD-1 pos NK cells failed to degranulate and release IFNγ, but exogenous IL-2 or IL-15 restored this defect. That PD-1 contributed to NK cell functional impairment and was not simply a marker of dysfunctional NK cells was confirmed in PD-1-transduced NKL cells. In vitro , PD-1 was induced at the surface of healthy control NK cells upon prolonged contact with cells expressing activating ligands, i.e. a condition mimicking persistent stimulation by tumor cells. Thus, PD-1 appears to plays a critical role in mediating NK cell exhaustion. The existence of this negative checkpoint fine-tuning NK activation highlights the possibility that manipulation of the PD-1 pathway may be a strategy for circumventing tumor escape not only from the T cell-, but also the NK-cell mediated immune surveillance.

T cell functions are affected by stiffness within the physiological Young's modulus range of 0.5 kPa to 100 kPa. Stiffness modulates T lymphocyte migration and morphological changes induced by TCR/CD3 triggering. Stiffness also increases TCR-induced immune system, metabolism and cell-cycle-related genes. Yet, upon TCR/CD3 stimulation, while cytokine production increases within a wide range of stiffness, from hundreds of Pa to hundreds of kPa, T cell metabolic properties and cell cycle progression are only increased by the highest stiffness tested (100 kPa). Finally, mechanical properties of adherent antigen-presenting cells modulate cytokine production by T cells. Together, these results reveal that T cells discriminate between the wide range of stiffness values found in the body and adapt their responses accordingly.

Cytokine secretion by T lymphocytes plays a central role in mounting adaptive immune responses. However, little is known about how newly synthesized cytokines, once produced, are routed within T cells and about the mechanisms involved in regulating their secretions. In this study, we investigated the role of cytoskeleton remodeling at the immunological synapse (IS) in cytokine secretion. We show that a key regulator of cytoskeleton remodeling, the Rho GTPase Cdc42, controls IFN-γ secretion by primary human CD4+ T lymphocytes. Surprisingly, microtubule organizing center polarity at the IS, which does not depend on Cdc42, is not required for cytokine secretion by T lymphocytes, whereas microtubule polymerization is required. In contrast, actin remodeling at the IS, which depends on Cdc42, controls the formation of the polymerized actin ring at the IS, the dynamic concentration of IFN-γ-containing vesicles inside this ring, and the secretion of these vesicles. These results reveal a previously unidentified role of Cdc42-dependent actin remodeling in cytokine exocytosis at the IS.