Effets des nanoparticules à base de Gadolinium AGuIX sur la reprogrammation fonctionnelle des macrophages induite par les rayonnements ionisants

Les macrophages associés aux tumeurs (TAMs) sont des composants essentiels du microenvironnement inflammatoire des tumeurs et sont associés à de mauvais pronostics cliniques dans la majorité des cancers. Les TAMs présentent principalement des fonctions anti-inflammatoires qui favorisent et soutiennent le remodelage tissulaire, la suppression immunitaire et la croissance tumorale. La conversion des TAMs anti-inflammatoires en phénotype pro-inflammatoire est récemment apparue comme une opportunité thérapeutique pour améliorer l'efficacité des traitements anticancéreux tels que la radiothérapie. Dans cette thèse, nous démontrons que les nanoparticules à base de gadolinium AGuIX seules et en combinaison avec des rayonnements ionisants, induisent des dommages à l'ADN, une réponse aux dommages à l'ADN induite par l'ataxie télangiectasie (ATM) dans les macrophages humains et déclenchent une reprogrammation pro-inflammatoire des macrophages. Ce processus, est associé à la phosphorylation de la protéine kinase active sur l'adénosine monophosphate (AMP) de la thréonine 1972 (AMPKT172*) et à la modulation de la dynamique mitochondriale. Nous démontrons également que l’extinction de l'AMPK réduit la fragmentation mitochondriale et la reprogrammation pro-inflammatoire des macrophages induits par les nanoparticules à base de gadolinium AGuIX et leur combinaison avec les rayonnements ionisants. Ce phénomène, révèle ainsi que l'AMPK joue un rôle central pour la reprogrammation pro-inflammatoire des macrophages. Dans l'ensemble, nos résultats identifient une nouvelle voie de signalisation induite par les nanoparticules à base de gadolinium AGuIX et leur traitement combiné avec des rayonnements ionisants, ciblent la polarisation des macrophages, altèrent la fonction des macrophages vers le phénotype pro-inflammatoire et améliorent l'efficacité de la radiothérapie.The tumor microenvironment is highly heterogenous and composed of tumor cells and various immune effector cells. Tumor-associated macrophages (TAMs) are essential components of the inflammatory microenvironment of tumors and are associated with poor clinical outcomes in the majority of cancers. TAMs mainly exhibit anti-inflammatory functions that promote and support tissue remodeling, immune suppression, and tumor growth. Converting anti-inflammatory TAMs into pro-inflammatory phenotype recently emerged as a therapeutic opportunity to improve the efficacy of anticancer treatments such as radiotherapy. Here we show that gadolinium-based nanoparticles AGuIX alone and in combination with ionizing radiation induce DNA damage and an Ataxia telangiectasia mutated (ATM)-DNA-damage response in human macrophages and trigger their pro-inflammatory reprogramming. This process is associated with the activating phosphorylation of the Adenosine Monophosphate (AMP) activated protein kinase on threonine 1972 (AMPKT172*) and the modulation of mitochondrial dynamic. Interestingly, we demonstrate that the depletion of the AMPK reduces the mitochondrial fragmentation and the pro-inflammatory reprogramming of macrophages elicited by gadolinium-based nanoparticles AGuIX and their combination with ionizing radiation, thus revealing that the AMPK plays a central role for the pro-inflammatory macrophage reprogramming. Altogether, our results identify a novel signaling pathway induced by gadolinium-based nanoparticles AGuIX and their combined treatment with ionizing radiation that target macrophage polarization, skew macrophage function toward the pro-inflammatory phenotype, and may enhance the effectiveness of radiotherapy

Gadolinium-based nanoparticles AGuIX and their combination with ionizing radiation trigger AMPK-dependent proinflammatory reprogramming of tumor-associated macrophages

Abstract Background Tumor-associated macrophages (TAMs) are essential components of the inflammatory microenvironment of tumors and are associated with poor clinical outcomes in the majority of cancers. TAMs mainly exhibit anti-inflammatory functions that promote and support the tissue remodeling, the immune suppression and the tumor growth. Regarding their plasticity, the functional reprogramming of anti-inflammatory TAMs into proinflammatory phenotype recently emerged as a therapeutic opportunity to improve the effectiveness of anticancer treatments such as radiotherapy. Results Here we show that gadolinium-based nanoparticles AGuIX alone and in combination with ionizing radiation (IR) induce in a dose-dependent manner, the accumulation of DNA double strand breaks, an Ataxia telangiectasia mutated (ATM)-dependent DNA-damage response, an increased expression of the Interferon regulatory factor 5 (IRF5) and the release of proinflammatory cytokines from targeted macrophages, thus directing their proinflammatory reprogramming. This process is associated with the activating phosphorylation of the Adenosine Monophosphate (AMP) activated protein kinase on threonine 172 (AMPKT172*) and the fragmentation of mitochondria. Furthermore, we demonstrate that the inactivation of AMPK reduces the mitochondrial fragmentation and the proinflammatory reprogramming of macrophages detected in response to AGuIX and their combination with IR. These results reveal that the AMPK-dependent regulation of mitochondrial fragmentation plays a central role during the proinflammatory reprogramming of macrophages. Accordingly, a positive correlation between AMPKT172* and proinflammatory activation of TAMs is detected following IR+AGuIX combination in syngeneic mouse model of colorectal cancer. Conclusions Altogether, our results identify a novel signaling pathway elicited by AGuIX and their combined treatment with IR, that targets macrophage polarization, skews macrophage functions toward the proinflammatory phenotype and may enhance the effectiveness of radiotherapy

AGuIX nanoparticle-nanobody bioconjugates to target immune checkpoint receptors

International audienceComparison of click chemistry and sortagging grafting strategies for functionalizing AGuIX nanoparticles with nanobodies to develop a tri-functional technology combining MRI imaging, radiotherapy, and immunotherapy by inhibiting immune checkpoints

NOX2-dependent ATM kinase activation dictates pro-inflammatory macrophage phenotype and improves effectiveness to radiation therapy

Although tumor-associated macrophages have been extensively studied in the control of response to radiotherapy, the molecular mechanisms involved in the ionizing radiation-mediated activation of macrophages remain elusive. Here we show that ionizing radiation induces the expression of interferon regulatory factor 5 (IRF5) promoting thus macrophage activation toward a pro-inflammatory phenotype. We reveal that the activation of the ataxia telangiectasia mutated (ATM) kinase is required for ionizing radiation-elicited macrophage activation, but also for macrophage reprogramming after treatments with γ-interferon, lipopolysaccharide or chemotherapeutic agent (such as cisplatin), underscoring the fact that the kinase ATM plays a central role during macrophage phenotypic switching toward a pro-inflammatory phenotype through the regulation of mRNA level and post-translational modifications of IRF5. We further demonstrate that NADPH oxidase 2 (NOX2)-dependent ROS production is upstream to ATM activation and is essential during this process. We also report that the inhibition of any component of this signaling pathway (NOX2, ROS and ATM) impairs pro-inflammatory activation of macrophages and predicts a poor tumor response to preoperative radiotherapy in locally advanced rectal cancer. Altogether, our results identify a novel signaling pathway involved in macrophage activation that may enhance the effectiveness of radiotherapy through the reprogramming of tumor-infiltrating macrophages

HIV-1 Envelope Overcomes NLRP3-Mediated Inhibition of F-Actin Polymerization for Viral Entry

International audiencePurinergic receptors and nucleotide-binding domain leucine-rich repeat containing (NLR) proteins have been shown to control viral infection. Here, we show that the NLR family member NLRP3 and the purinergic receptor P2Y2 constitutively interact and regulate susceptibility to HIV-1 infection. We found that NLRP3 acts as an inhibitory factor of viral entry that represses F-actin remodeling. The binding of the HIV-1 envelope to its host cell receptors (CD4, CXCR4, and/or CCR5) overcomes this restriction by stimulating P2Y2. Once activated, P2Y2 enhances its interaction with NLRP3 and stimulates the recruitment of the E3 ubiquitin ligase CBL to NLRP3, ultimately leading to NLRP3 degradation. NLRP3 degradation is permissive for PYK2 phosphorylation (PYK2Y402*) and subsequent F-actin polymerization, which is required for the entry of HIV-1 into host cells. Taken together, our results uncover a mechanism by which HIV-1 overcomes NLRP3 restriction that appears essential for the accomplishment of the early steps of HIV-1 entry

Ação de rizobactérias sobre fungos fitopatogênicos

Although tumor-associated macrophages have been extensively studied in the control of response to radiotherapy, the molecular mechanisms involved in the ionizing radiation-mediated activation of macrophages remain elusive. Here we show that ionizing radiation induces the expression of interferon regulatory factor 5 (IRF5) promoting thus macrophage activation toward a pro-inflammatory phenotype. We reveal that the activation of the ataxia telangiectasia mutated (ATM) kinase is required for ionizing radiation-elicited macrophage activation, but also for macrophage reprogramming after treatments with γ-interferon, lipopolysaccharide or chemotherapeutic agent (such as cisplatin), underscoring the fact that the kinase ATM plays a central role during macrophage phenotypic switching toward a pro-inflammatory phenotype through the regulation of mRNA level and post-translational modifications of IRF5. We further demonstrate that NADPH oxidase 2 (NOX2)-dependent ROS production is upstream to ATM activation and is essential during this process. We also report that the inhibition of any component of this signaling pathway (NOX2, ROS and ATM) impairs pro-inflammatory activation of macrophages and predicts a poor tumor response to preoperative radiotherapy in locally advanced rectal cancer. Altogether, our results identify a novel signaling pathway involved in macrophage activation that may enhance the effectiveness of radiotherapy through the reprogramming of tumor-infiltrating macrophages