HIV-1 virion accumulation and ATP-induced release in human primary monocyte-derived macrophages AIDS Immunopathogenesis Unit Vita-Salute San Raffaele University, Milan, Italy Francesca Graziano PhD Student Poster n°WEPDA0103

Macrophage Virion synthesis & accumulation CD4 + T cell Cell Death What is the nature of HIV-containing vacuoles? What else is contained in addition to HIV virions?

ATP P2X7 Receptor Permeabilized plasma membrane Pyroptotic/Necrotic Pathway Exosome Pathway Microvesicles Pathway Autophagic Pathway HIV-1 Hypothesis: Are the intracellular HIV-1 virions released by extracellular ATP stimulation, like IL-1  ? IL-1 β ? The IL-1  Release Pathway. A potential model for HIV-1 infection of Mø?

MODEL (I): Chronically infected promonocytic cell line U1 (2 copies of integrated virus/cell). N=8 * *** oxATP ATP HIV-1 1 min.5 min.10 min. Untreated oxATP ATP N=3 * * IL-1  N=8 uPA prevents virion release from PMA stimulated U1 cells uPA: urokinase-type Plasminogen Activator ATP induces a release pathway in stimulated U1 cells

Alternatively Activated M2-MDM Classically Activated M1-MDM IL-4 IFN-  MDM N=18 MODEL (II) HIV-1 Infection of primary monocyte-derived macrophages (MDM) N=25 MDM 10’20’ 30’ M1-MDM M2-MDM 10’20’ 30’10’20’ 30’ Untreated ATP ATP induces the release of HIV virions from HIV-1 infected MDM p24 UN 1 mM ATP FSC MDM UN 1 mM ATP M2-MDM ATP reduces the intracellular amount of HIV-1 virions 16,79,63 20,2 6,78 1 representative of 7

Conclusions HIV-1 virions accumulate in intracellular vacuoles in differentiated U1 cells and primary MDM. ATP promotes the release of IL-1  and HIV-1 virions in both cell types. These results suggest that HIV-1 exploits the microvesicle pathway to be released from infected macrophages.

Acknowledgements AIDS Immunopathogenesis Unit Guido Poli Massimo Alfano Elisa Vicenzi INSPE Division of Neuroscience Roberto Furlan Livia Garzetti Humanitas Clinical and Research Center Massimo Locati Poster N° WEPDA0103