* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download C. neoformans
Epigenetics of neurodegenerative diseases wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Gene therapy wikipedia , lookup
Ridge (biology) wikipedia , lookup
Oncogenomics wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Minimal genome wikipedia , lookup
Genome evolution wikipedia , lookup
Genome (book) wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
RNA interference wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Gene nomenclature wikipedia , lookup
Microevolution wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Designer baby wikipedia , lookup
Gene expression programming wikipedia , lookup
Gene expression profiling wikipedia , lookup
Helitron (biology) wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Cryptococcus neoformans Basidiomycete yeast Both an opportunistic and a primary pathogen mainly affecting CNS Serotype D More frequent in Europe Serotype A Worldwide distribution Serotypes B and C (var. gattii): Tropical and subtropical regions Primarily infects hosts with normal immune function Cryptococcus neoformans Important pathogen Some molecular biology foundation Significant number of investigators Genome sequence in progress Well-studied pathophysiology Known virulence phenotypes Excellent animal models A number of yeasts are pathogenic in the C. elegans model C. laurentii % Survival 100 R. mucilaginosa 75 50 S. cerevisiae 25 C. neoformans H99 C. parapsilosis 0 0 100 Time (hrs) 200 Lifespan of wild type C. elegans on lawns of non-pathogenic organisms % Survival 100 C. kuetzingii 75 C. laurentii E. coli OP50 50 25 0 0 200 400 Time (hours) 600 C. neoformans strains from different serogroups are pathogenic 100 % Survival C. laurentii 75 C. neoformans serotype A 50 C. neoformans serotype D C. neoformans serotype A 25 C. neoformans serotype B/C 0 0 100 200 Time (hrs) 300 Killing is not solely a matricidal effect: Glp-4 nematodes die approximately 2 days later than N2 when placed on lawns of C. neoformans, but their lifespan is significantly shorter than on lawns of nonpathogenic cryptococci C. neoformans does not colonize C. elegans: N2 nematodes were fed on lawns of C. neoformans and then at different time-points transferred to lawns of non-pathogenic cryptococci. All nematodes that survived transfer were rescued, regained normal non-distended anatomy and no C. neoformans yeast cells could be cultured followed “grinding” of the rescued worms. Daf-2 nematodes have a significantly longer survival on lawns of C. neoformans compared to N2s (LT50: 9 vs. 4.5 days) Expression of Cryptococcal Virulence Genes inside C. elegans • The MAT mating-type alpha locus containing the MFalpha gene has been linked with virulence • Cryptococcal cells containing the promoter of MFalpha1 fused to GFP documented the expression of this gene in the CNS of infected rabbits. FACS analysis and corresponding phase-contrast and epifluorescent microscopy of MF1::GFP from CSF Evaluation of Cryptococcal Virulence Factors in C. elegans GPA1 regulates capsule and melanin production in C. neoformans Gpa enhances virulence in C. elegans % Survival 100 75 gpa 50 H 99 25 GPA 0 0 50 100 Time (hrs) 150 200 PKA1 gene encods the major cAMP-dependent protein kinase catalytic subunit and PKR1 gene encods the protein kinase A (PKA) regulatory subunit PKA/ PKR PKA1 enhances virulence in mice PKA1 enhances virulence in the C. elegans model 100 % Survival pka 75 50 25 H 99 PKA 0 0 50 100 Time (hrs) 150 200 A strain with a mutation involving PKR1 is hypervirulent in animal models (A) Survival (B) Corticosteroid immunosuppressed rabbits. Quantitative cultures (C) Quantitative cultures (brain/lung/spleen) The same pkr1 mutant is hypervirulent in the C. elegans model % Survival 100 75 H99 50 25 pkr 0 0 50 Time (hrs) 100 150 Melanogenesis from dopamine in C. neoformans When DA was added in media, the lacc+ strain of C. neoformans was more virulent than an otherwise isogenic lacc- strain % Survival 100 Lacc- DAlacc+ DA- 75 50 lacc- DA+ 25 lacc+ DA+ 0 0 50 Time (hrs) 100 Nematodes with enhanced susceptibility to bacterial pathogens are also more susceptible to C. neoformans 100 % Survival H99 N2 75 H99 esp8 50 25 H99 esp2 0 0 20 40 Time (hrs) 60 C. neoformans/C. elegans model system Summary C. elegans can utilize the non-pathogenic yeasts C. laurentii and C. kuetzingii as a sole source of food The human pathogenic yeast C. neoformans kills C. elegans Several C. neoformans genes, previously shown to be involved in mammalian virulence, also play a role in C. elegans killing The nematode response to C. neoformans may have some interesting similarities to the response of mammals Acknowledgements Calderwood laboratory MGH Rhonda Feinbaum Dennis Kim Kaveh Ashrafi MIT Gerry Fink Robert Wheeler Ausubel laboratory Duke University John R. Perfect Joseph Heitman John McCusker Andrew Alspaugh Gary M. Cox Elizabeth A. Wills Postdoctoral funding: Boston University Stu Levitz Saint Louis University Jennifer K. Lodge Albert Einstein College of Medicine Arturo Casadevall Howard Hughes Medical Institute