Pneumocystis murina
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ABSTRACT:
PROVIDER: PRJNA20535 | ENA |
REPOSITORIES: ENA
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Project description:Pneumocystis is a relevant genetic system to study centromere formation in relation with host adaptation. How centromeres are formed and maintained in strongly host adapted fungal pathogens is poorly investigated. Centromeres are genomic regions that coordinate accurate chromosomal segregation during mitosis and meiosis. Yet, despite their essential function, centromeres evolve rapidly across eukaryotes. CENP-A, a variant of histone H3 is the epigenetic marker that define centromeres in most eukaryotes. Centromeres are often the sites of chromosomal breaks which contribute to genome shuffling and promote speciation by inhibiting gene flow. Genome shuffling allows genome reconfiguration suitable for survival in new environment such as pathogen adaptation to new hosts. Here, we study the evolution of centromeres in closely related species of mammalian specific pathogens of the fungal phylum of Ascomycota. Long term culture of Pneumocystis species is currently untenable. Using heterologous complementation, we show that Pneumocystis CENP-A ortholog is functionally equivalent to fission yeast Cnp1. Using a short-term in vitro culture, infected animal models and ChIP-seq, we identified centromeres in three Pneumocystis species that diverged ~100 Mya ago. Each species has 17 unique short regional centromeres (< 10kb) in 17 monocentric chromosomes. The centromeres are flanked by heterochromatin. They span active genes, lack conserved DNA sequence motifs, and repeats.These features suggest an epigenetic specification of centromere function.
2024-02-08 | GSE232454 | GEO
Project description:Pneumocystis pneumonia is a major cause of morbidity and mortality in immunocompromised patients, particularly those infected with HIV. In this study, we evaluated the potential of oral immunization with live Pneumocystis to elicit protection against respiratory infection with Pneumocystis murina. C57BL/6 mice vaccinated with live P. murina using a prime-boost vaccination strategy were protected from a subsequent lung challenge with P. murina at 2, 7, 14, and 28 d postinfection even after CD4(+) T cell depletion. Specifically, vaccinated immunocompetent mice had significantly faster clearance than unvaccinated immunocompetent mice and unvaccinated CD4-depleted mice remained persistently infected with P. murina. Vaccination also increased numbers of CD4(+) T cells, CD8(+) T cells, CD19(+) B cells, and CD11b(+) macrophages in the lungs following respiratory infection. In addition, levels of lung, serum, and fecal P. murina-specific IgG and IgA were increased in vaccinated animals. Furthermore, administration of serum from vaccinated mice significantly reduced Pneumocystis lung burden in infected animals compared with control serum. We also found that the diversity of the intestinal microbial community was altered by oral immunization with P. murina. To our knowledge, our data demonstrate for the first time that an oral vaccination strategy prevents Pneumocystis infection.
| S-EPMC4779750 | biostudies-literature
Project description:Pathogenic fungus that causes pneumonia in rats
| PRJNA9515 | ENA
Project description:Pathogenic fungus that causes pneumonia in immunocompromised persons
| PRJNA20531 | ENA
Project description:Pneumocystis pneumonia remains a common opportunistic infection in the diverse immunosuppressed population. One clear risk factor for susceptibility to Pneumocystis is a declining CD4(+) T cell count in the setting of HIV/AIDS or primary immunodeficiency. Non-HIV-infected individuals taking immunosuppressive drug regimens targeting T cell activation are also susceptible. Given the crucial role of CD4(+) T cells in host defense against Pneumocystis, we used RNA sequencing of whole lung early in infection in wild-type and CD4-depleted animals as an unbiased approach to examine mechanisms of fungal clearance. In wild-type mice, a strong eosinophil signature was observed at day 14 post Pneumocystis challenge, and eosinophils were increased in the bronchoalveolar lavage fluid of wild-type mice. Furthermore, eosinophilopoiesis-deficient Gata1(tm6Sho)/J mice were more susceptible to Pneumocystis infection when compared with BALB/c controls, and bone marrow-derived eosinophils had in vitro Pneumocystis killing activity. To drive eosinophilia in vivo, Rag1(-/-) mice were treated with a plasmid expressing IL-5 (pIL5) or an empty plasmid control via hydrodynamic injection. The pIL5-treated mice had increased serum IL-5 and eosinophilia in the lung, as well as reduced Pneumocystis burden, compared with mice treated with control plasmid. In addition, pIL5 treatment could induce eosinophilia and reduce Pneumocystis burden in CD4-depleted C57BL/6 and BALB/c mice, but not eosinophilopoiesis-deficient Gata1(tm6Sho)/J mice. Taken together, these results demonstrate that an early role of CD4(+) T cells is to recruit eosinophils to the lung and that eosinophils are a novel candidate for future therapeutic development in the treatment of Pneumocystis pneumonia in the immunosuppressed population.
| S-EPMC4475669 | biostudies-literature
Project description:Previous studies have shown that Pneumocystis binds to pneumocytes, but the proteins responsible for binding have not been well defined. Mucins are the major glycoproteins present in mucus, which serves as the first line of defence during airway infection. MUC1 is the best characterised membrane-tethered mucin and is expressed on the surface of most airway epithelial cells. Although by electron microscopy Pneumocystis primarily binds to type I pneumocytes, it can also bind to type II pneumocytes. We hypothesized that Pneumocystis organisms can bind to MUC1 expressed by type II pneumocytes. Overexpression of MUC1 in human embryonic kidney HEK293 cells increased Pneumocystis binding, while knockdown of MUC1 expression by siRNA in A549 cells, a human adenocarcinoma-derived alveolar type II epithelial cell line, decreased Pneumocystis binding. Immunofluorescence labelling indicated that MUC1 and Pneumocystis were co-localised in infected mouse lung tissue. Incubation of A549 cells with Pneumocystis led to phosphorylation of ERK1/2 that increased with knockdown of MUC1 expression by siRNA. Pneumocystis caused increased IL-6 and IL-8 secretion by A549 cells, and knockdown of MUC1 further increased their secretion in A549 cells. Taken together, these results suggest that binding of Pneumocystis to MUC1 expressed by airway epithelial cells may facilitate establishment of productive infection.
| S-EPMC7202957 | biostudies-literature
Project description:Pneumocystis has a large multicopy gene family encoding proteins related to the major surface glycoprotein (Msg), whose functions are largely unknown. We expressed one such protein of Pneumocystis murina, p57, which is encoded by 3 highly conserved genes, and demonstrated by immunoblot that immunocompetent mice that were immunized with crude Pneumocystis antigens or that had cleared Pneumocystis infection developed antibodies to p57. Using hyperimmune anti-p57 serum combined with immunolabeling, we found that p57 was expressed by small trophic forms and intracystic bodies, whereas it was not expressed on larger trophic forms or externally by cysts. Expression of p57 and Msg by trophic forms was largely mutually exclusive. Treatment of infected animals with caspofungin inhibited cyst formation and markedly decreased p57 expression. While p57 expression was seen in immunocompetent mice infected with Pneumocystis, immunization with recombinant p57 did not result in altered cytokine expression by lymphocytes or in diminished infection in such mice. Thus, p57 appears to be a stage-specific antigen of Pneumocystis that is expressed on intracystic bodies and young trophic forms and may represent a mechanism to conserve resources in organisms during periods of limited exposure to host immune responses.
| S-EPMC6279149 | biostudies-literature
Project description:Dermatophyte fungus that causes scalp infections
| PRJNA20579 | ENA
Project description:Glucan is the major cell wall component of Pneumocystis cysts. In the current study, we have characterized Pneumocystis Bgl2 (EC 3.2.1.58), an enzyme with glucanosyltransferase and ?-1,3 endoglucanase activity in other fungi. Pneumocystis murina, Pneumocystis carinii, and Pneumocystis jirovecii bgl2 complementary DNA sequences encode proteins of 437, 447, and 408 amino acids, respectively. Recombinant P. murina Bgl2 expressed in COS-1 cells demonstrated ?-glucanase activity, as shown by degradation of the cell wall of Pneumocystis cysts. It also cleaved reduced laminaripentaose and transferred oligosaccharides, resulting in polymers of 6 and 7 glucan residues, demonstrating glucanosyltransferase activity. Surprisingly, confocal immunofluorescence analysis of P. murina-infected mouse lung sections using an antibody against recombinant Bgl2 showed that the native protein is localized primarily to the trophic form of Pneumocystis in both untreated mice and mice treated with caspofungin, an antifungal drug that inhibits ?-1,3-glucan synthase. Thus, like other fungi, Bgl2 of Pneumocystis has both endoglucanase and glucanosyltransferase activities. Given that it is expressed primarily in trophic forms, further studies are needed to better understand its role in the biology of Pneumocystis.
| S-EPMC6941498 | biostudies-literature