NLRX1 Facilitates Histoplasma capsulatum-Induced LC3-Associated Phagocytosis for Cytokine Production in Macrophages
Year: 2018
Type: article
Abstract: LC3-associated phagocytosis (LAP) is an emerging non-canonical autophagy process that bridges signaling from pattern-recognition receptors (PRRs) to autophagic machinery. LAP formation results in incorporation of lipidated LC3 into phagosomal membrane (termed LAPosome). Increasing evidence reveals that LAP functions as an innate defense mechanism against fungal pathogens. However, the molecular mechanism involved and the consequence of LAP in regulating anti-fungal immune response remain largely unexplored. Here we show that Histoplasma capsulatum is taken into LAPosome upon phagocytosis by macrophages. Interaction of H. capsulatum with Dectin-1 activates Syk and triggers subsequent NADPH oxidase-mediated reactive oxygen species (ROS) response that is involved in LAP induction. Inhibiting LAP induction by silencing LC3α/β or treatment with ROS inhibitor impairs the activation of MAPK-AP-1 pathway, thereby reduces macrophage proinflammatory cytokine response to H. capsulatum. Additionally, we unravel the importance of NLRX1 in fungus-induced LAP. NLRX1 facilitates LAP by interacting with TUFM which associates with autophagic proteins ATG5-ATG12 for LAPosome formation. Macrophages from Nlrx1-/- mice or TUFM-silenced cells exhibit reduced LAP induction and LAP-mediated MAPKs-AP-1 activation for cytokine response to H. capsulatum. Furthermore, inhibiting ROS production in Nlrx1-/- macrophages almost completely abolishes H. capsulatum-induced LC3 conversion, indicating that both Dectin-1/Syk/ROS-dependent pathway and NLRX1-TUFM complex-dependent pathway collaboratively contribute to LAP induction. Our findings reveal new pathways underlying LAP induction by H. capsulatum for macrophage cytokine response.
Source: Frontiers in Immunology
Authors: Juin-Hua Huang, Chu-Yu Liu, Sheng-Yang Wu, Wen-Yu Chen, Tzu-Hsuan Chang, Hung-Wei Kan, Sung-Tsang Hsieh, Jenny P.-Y. Ting, Betty A. Wu-Hsieh
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,801
Funders: Academia Sinica, Ministry of Science and Technology, Taiwan, National Taiwan University Hospital, National Taiwan University, National Institutes of Health, National Cancer Institute, National Institute of Allergy and Infectious Diseases, National Institute of Diabetes and Digestive and Kidney Diseases
Awards: Colitis, Colon Cancer and the NLR Family, Applying Mouse Models to Unveil How Mosquito Saliva/Sge Modulate the Pathogenesis of Dengue Hemorrhage and to Test New Anti-Dengue Drugs( III ), The Activation and Regulation of Inflammasome Response to Histoplasma Capsulatum, Discovery of New Innate Immune Pathways in Viral Recognition, G3415426386, Plexin-A1: Regulation by CIITA and Immunologic Function, Identifying Microbial, Epithelial and Immune Cell Interactions that Mediate Mucosal Homeostasis and Determine IBD Phenotypes, Plexin-A1: Regulation by CIITA and immunologic function, G9000168410, Molecular and Functional Analysis of Innate Immune Receptors
OpenAlex ID: W2902385998