Project description:β-glucans, which can activate innate immune responses, are a major component in the cell wall of the cyst form of Pneumocystis. In the current study we examined whether β-1,3 glucans are masked by surface proteins in Pneumocystis, and what role β-glucans play in Pneumocystis-associated inflammation. For 3 species, including P. jirovecii, which causes Pneumocystis pneumonia (PCP) in humans, P. carinii, and P. murina, β-1,3 glucans were masked in most organisms, as demonstrated by increased exposure following trypsin treatment. Using Q-PCR and microarray techniques, we demonstrated in a mouse model of PCP that treatment with caspofungin, an inhibitor of β-1,3 glucan synthesis, for 21 days, decreased expression of a broad panel of inflammatory markers, including IFN-γ, TNF-α, IL-1β, IL-6, and multiple chemokines/chemokine ligands. Thus, β-glucans in Pneumocystis cysts are largely masked, which likely decreases innate immune activation; this mechanism presumably was developed for interactions with immunocompetent hosts, in whom organism loads are substantially lower. In immunosuppressed hosts with a high organism burden, organism death and release of glucans appears to be an important contributor to deleterious host inflammatory responses.
Project description:We collected a single broncho alveolar lavage from single human patient with Pneumocystis jirovecii pneumonia. Total RNA was extracted using the Ribopure Yeast Kit (Ambion), according to the manufacturer's instructions. To obtain sufficient amount of RNA, total RNA was amplified using NuGEN OvationRNA-seq system and used to build a non-strand-specific library. The library was then sequenced using Illumina HiSeq 2000 technologies. The raw NGS data is archived in the ENA SRA and the trancriptome assembly is in ENA EMBL-bank.
Project description:Pneumocystis pneumonia is an opportunistic pneumonia that has been increasing in non-HIV patients in recent years. To obtain a better understanding of the cellular and molecular mechanisms involved in disease pathogenesis, we profile the transcriptomes of mouse lungs with Pneumocystis pneumonia and from uninfected control subjects using single-cell RNA sequencing, yielding multiple populations of myeloid cells, T cells and B cells. We uncover a PCP-associated TREM2+ subpopulation of interstitial macrophages, which expands in PCP, differentiates from Ly6C+ monocytes. We also define the subsets of effector CD4+ T cells that expand after the infection of Pneumocystis. Finally, intercellular crosstalk between interstitial macrophages and effector CD4+ T cells via multiple ligand and receptor interactions reveals several anti-pneumocystis pathways. Our work dissects unanticipated aspects of the cellular and molecular basis of Pneumocystis pneumonia at a single-cell level, and provides a conceptual framework for the discovery of rational therapeutic targets in Pneumocystis pneumonia.