Title: Role of C. glabrata cAMP-PKA pathway in morphology, biofilm development and virulence
Authors: De Brucker, Katrijn
Van Dijck, Patrick #
Issue Date: Mar-2007
Conference: VIB general meeting location:Blankenberge, België date:1-2 March 2007
Abstract: Due to the widespread and increased use of immunosuppressive therapy together with broad spectrum antibiotics, the frequency of mucosal and systemic infections caused by Candida has increased significantly. Candida infections can be mucosal or systemic and are common in immunocompromised patients. Although C. albicans is the most common Candida species, C. glabrata already causes 20% of systemic candidiasis and 30% of urinary tract infections. C. glabrata is resistant to fluconazole, a commonly used antifungal, and has a higher mortality rate compared to C. albicans.
In this project we will investigate the role of the cAMP-PKA-pathway in morphology, biofilm development and virulence. C. glabrata deletion strains will be made; homologues of ScGPR1, ScGPA2, ScCYR1, ScKRH1 and ScKRH2 will be deleted (in collaboration with Prof. Kuchler, University and Biocenter of Vienna). We will examine if these C. glabrata genes can complement the respective deletion mutants of S. cerevisiae. To be able to make more deletions in one strain, we will develop a system based on the SAT1 flipping method, which was developed for C. albicans. The morphology of these mutants will be analysed in liquid and solid medium. The cAMP-signal of the mutants, induced by glucose, and the ligand of Gpr1 will be investigated. If CgGpr1 binds glucose and sucrose, we will investigate if the amino acids of ScGpr1 that recognize sucrose, have the same function in CgGrp1. The interaction between the ligand and these amino acids will be investigated using SCAM-analysis. If glucose or sucrose doesn’t induce the cAMP-signal, amino acids will be tested as possible ligands for Gpr1. The TAP-method will be used to identify the proteins which interact with C. glabrata Gpr1, Gpa2, Cyr1, Krh1/2, Ira1/2 and Tpk1/2. Changes in the expression patterns of the deletion mutants will be determined using micro-arrays. The role of the C. glabrata cAMP-PKA-pathway in the general stress response will be checked by testing the different mutants for the ligand induced mobilisation of trehalose, repression of STRE-controlled genes and heat tolerance. The involvement of the cAMP-PKA-pathway in adhesion, the first stage of biofilm development, will be examined. This will be done by using the in vitro polyurethane disc system. By using an in vitro model for oral and cutaneous candidiasis (in collaboration with Prof. Rupp, Fraunhofer Institute) and an in vivo model for systemic candidiasis, the involvement of the cAMP-PKA-pathway in virulence will be checked. The interaction between the different mutants and macrophages will be examined (in collaboration with Prof. Diez-Orejas, Universidad Complutense de Madrid).
If the C. glabrata cAMP-PKA-pathway turns out to be involved in virulence and/or biofilm development, then antifungal compounds can be developed which can inhibit important proteins of the cAMP-PKA-pathway. These compounds can be used in combination with already existing antifungals for the treatment of fungal infections.
Publication status: published
KU Leuven publication type: IMa
Appears in Collections:Molecular Microbiology and Biotechnology Section - miscellaneous
# (joint) last author

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