Project description:Alveolar macrophages maintain lung homeostasis and are critical for host defense to respiratory pathogens, including influenza virus. Yet how aging impacts alveolar macrophages remains unclear. Here, we found that aging reduces the proliferation and concentration of alveolar macrophages under basal conditions in mice. Transcriptomic analysis revealed that aging induces a down regulation in cell cycling pathways in alveolar macrophages. Functionally, aging impaired the capacity of alveolar macrophages to phagocytose in vivo, and also increased influenza virus-induced lung damage, morbidity and mortality. Depleting alveolar macrophages indicated that these cells were critical for accelerated mortality during influenza viral lung infection with aging. Adoptive transfer experiments demonstrated that aging impaired the ability of alveolar macrophages to reduce lung damage after influenza viral infection. Thus, our study has revealed that aging impairs alveolar macrophages to resolve damageand increases mortality after influenza viral infection.
Project description:Resident memory B (BRM) cells develop and persist in the lungs of influenza infected mice and humans but their contribution to recall responses following rechallenge has not been defined. We used scRNA-seq to identify early changes in lung immune cell composition and gene expression following secondary influenza infection and tested the effect of alveolar macrophage depletion (using intranasally delivered CLL). We found an alveolar macrophage dependent upregulation of IFNG-associated pathways after influenza rechallenge, that included increased expression of CXCL9, CXCL10 and CCL5 in myeloid cells.
Project description:The importance of unanchored Ub in innate immunity has been shown only for a limited number of unanchored Ub-interactors. We investigated what additional cellular factors interact with unanchored Ub and whether unanchored Ub plays a broader role in innate immunity. To identify unanchored Ub-interacting factors from murine lungs, we used His-tagged recombinant poly-Ub chains as bait. These chains were mixed with lung tissue lysates and protein complexes were isolated with Ni-NTA beads. Sample elutions were subjected to mass spectrometry (LC-MSMS) analysis.
Project description:This project is based upon the fundamental observation that alveolar macrophage-derived extracellular vesicles (AM-EVs), when internalized by neighboring epithelial cells, inhibit their infection by influenza virus. This inhibitory activity of AM-EVs is abolished when AMs are treated with cigarette smoke extract (CSE). We chose to survey the AM-EV proteome in an effort to identify candidate proteins whose abundance within EVs was downregulated by CSE treatment of AMs, thus explaining the ability of CSE to abrogate the inhibitory activity against influenza.
