ABSTRACT: Coccidioidomycosis increases its area of geographic risk: Molecular detection and isolation of Coccidioides immitis in Washington State from soil associated with recent human infection
Project description:Coccidioides immitis (C. immitis) is a dimorphic fungus that causes disease in mammals including human beings. It grows as a mycelium in the soil but differentiates into a pathogenic structure called a spherule in the host. We compared the transcriptome of C. immitis mycelia and day 2 and day 8 spherules grown in vitro using a custom custom oligonucleotide microarray from Nimblegen.
Project description:Coccidioides immitis (C. immitis) is a dimorphic fungus that causes disease in mammals including human beings. It grows as a mycelium in the soil but differentiates into a pathogenic structure called a spherule in the host. We compared the transcriptome of C. immitis mycelia and day 2 and day 8 spherules grown in vitro using a custom custom oligonucleotide microarray from Nimblegen. C. immitis RS strain isolated from infected mice was grown on agar. Arthroconidia was harvested and inoculated into mycelial spores. RNA was extracted from spores at different days post-inoculation and hybridized to a custom Nimblegen array, in order to identify differentially expressed genes between mycelia and spherules.
Project description:Mouse strains have been identified that are resistant (i.e. DBA/2) or susceptible (i.e. C57BL/6) to infection from pathogenic fungus Coccidioides immitis. However, the genetic and immunological basis for this difference has not been fully characterized. Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis.
Project description:Mouse strains have been identified that are resistant (i.e. DBA/2) or susceptible (i.e. C57BL/6) to infection from pathogenic fungus Coccidioides immitis. However, the genetic and immunological basis for this difference has not been fully characterized. Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. C57BL/6 and DBA/2 mice were infected with arthoconidia of C. immitis and RNA was extracted at different days post-infection and hybridized to Affymetrix microarrays (MGU74Av2), in order to identify differentially expressed genes between the two strains.
Project description:Our previous data suggested that CXC ELR+ chemokines might be involved in neutrophil recruitment to the lungs during Coccidioides infection. To test that hypothesis, we infected IL-8R2 (Cxcr2) KO mice on a BALB/c background. IL-8R2 KO mice had fewer neutrophils in infected lungs than BALB/c controls, but unexpectedly the IL-8R2 KO mice also had 10-fold fewer organisms in their lungs than did control mice. To better understand the differences in IL-8R2 KO mouse lungs during Coccidioides infection we performed RNA-seq on lung tissue from uninfected and Coccidioides immitis infected mouse lungs in control and IL-8R2 (Cxcr2) KO mice. IL-8R2 KO mouse lungs had higher expression of genes associated with lymphocyte activation, including Th1 and Th17-related genes Ifnγ and Il17a and transcription factors Stat1 and Rorc. Bronchial alveolar lavage (BAL) fluid from infected IL-8R2 KO mice similarly contained more IL-17A and IFNγ.
Project description:Coccidioides immitis and posadasii are dimorphic fungi that transform from mycelia with internal arthroconidia in the soil to a tissue form known as a spherule. Genes that were highly up-regulated in young spherules include a spherule surface protein and iron and copper membrane transporters. Genes that are unique to Coccidioides spp. are also over-represented in this group, suggesting that they may be important for spherule differentiation. Enriched GO terms in up-regulated genes in young spherules include oxidation/reduction, response to stress and membrane proteins. Down-regulated genes are enriched for transcription factors, especially helix-loop-helix and C2H2 type zinc finger domain-containing proteins which is consistent with the dramatic change in transcriptional profile. Almost all genes that are up-regulated in young spherules remain up-regulated in mature spherules, but a small number of genes are differentially expressed in those two stages of spherule development. Mature spherules express more Hsp31, and amylase than young spherules and less tyrosinase. Some expression of transposons was detected and most of the differentially expressed transposons were up-regulated in spherules.
Project description:Coccidioidomycosis (Valley Fever) is an emerging endemic fungal infection with a rising incidence and an expanding geographic range. It is caused by Coccidiodes, which are thermally dimorphic fungi that grow as mycelia in soil but transition in the lung to form pathogenic spherules. The regulatory mechanisms underlying this transition are not understood. Exploiting capped small (cs)RNA-seq, which identifies actively initiated stable and unstable transcripts and thereby detects acute changes in gene regulation with remarkable sensitivity, here we report the changes in architectural organization and key sequence features underlying phase transition of this highly pathogenic fungus. Spherule transition was accompanied by large-scale transcriptional reprogramming, functional changes in transcript isoforms, and a massive increase in promoter-distal transcription of ncRNAs. Analysis of spherule-activated regulatory elements revealed a motif predicted to recruit a WOPR family transcription factor, which are known regulators of virulence in other fungi. We identify CIMG_02671 as a C. immitis WOPR homologue and show that it activates transcription in a WOPR motif-dependent manner, suggesting it is an important regulator of pathogenic phase transition. Collectively, this also highlights csRNA-seq as a powerful means to identify transcriptional mechanisms that control pathogenesis.
