Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: The purpose of this project was to understand how fungal pathogens cause disease and to investigate a new approach to the discovery of anti-fungal drug therapies. During this granting period, we have identified 21 small molecules that can inhibit the ability of the pathogenic yeast Candida albicans to undergo a shape change that is necessary for its ability to cause disease. Some of these molecules also block the ability of Candida albicans to form biofilms, which is a major cause of fungal disease in the human host. These findings were published in peer-reviewed publications and discussed at scientific meetings. Based on these outcomes, we will investigate the mechanisms by which several of these small molecules affect the signaling pathways needed for Candida albicans virulence and we will assay clinical Candida albicans isolates for their susceptibility to the small molecules. PARTICIPANTS: The undergraduate students Katelyn McLaughlin, Ariel Grald, Nathan Borochoff-Porte, and Dylan White performed experiments during this granting period. The graduate student John Midkiff performed experiments during this granting period. The principal investigator Doug Johnson performed experiments during this granting period. Experimental results were discussed by all participants at weekly lab meetings and biweekly joint lab meetings with other labs in MMG. TARGET AUDIENCES: Fungal infections affect predominantly immunocompromised individuals, such as burn patients, chemotherapy patients, and AIDS patients. Therefore, new anti-fungal therapeutic approaches examined in these studies are aimed at this target audience. These studies also have an impact on our understanding of basic cell signaling pathways in Candida albicans and as such will be of interest to cell biologists in general. PROJECT MODIFICATIONS: There are no major changes in the approaches proposed.
Impacts
We have identified 21 small molecules that block a shape change that is needed for Candida albicans to cause disease. Some of these molecules also block the ability of Candida albicans to form biofilm, which can lead to increased pathogenesis in the human host. Analysis of these small molecules may lead to new anti-fungal therapeutics in the future and new ways to block fungal biofilms. As fungal infections are a major source of disease for immunocompromised individuals, such as chemotherapy patients and AIDS patients, these findings may lead to new ways to combat these diseases.
Publications
- Toenjes, K.A., B.C. Stark, K.M. Brooks, D.K. Butler, and D.I. Johnson. 2009. Inhibitors of cellular signaling are cytotoxic or block the budded-to-hyphal transition in the pathogenic yeast Candida albicans. J. Med. Microbiol. 58:779-790.
- Cole, K.C., J.-E.R. Barbour, B.M. Marble, J.F. Midkiff, and D.I. Johnson. 2009. Multiple proteins and phosphorylations regulate S. cerevisiae Cdc24p localization; FEBS Lett. 583:3339-3343.
- Almeida, A.J., Cunha, C., Carmona, J.A., Sampaio-Marques, B., Carvalho, A., Malavazi, I., Steensma, H.Y., Johnson, D.I., Leao, C., Logarinho, E., Goldman, G.H., Castro, A.G., Ludovico, P., Rodrigues, F. 2009. Cdc42p controls yeast-cell shape and virulence in Paracoccidioides brasiliensis. Fung. Genet. Biol., in press.
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Progress 10/01/07 to 09/30/09
Outputs
OUTPUTS: The most significant outputs for this completed project were the training of 9 undergraduate students, 3 graduate students, and 1 post-baccaleureate student in my research lab, the publishing of one research article, and the presentation of our research findings at a regional conference at Dartmouth University. PARTICIPANTS: During this granting period, 9 undergraduate students, 3 graduate students, and 1 post-baccaleureate student were trained in my lab. TARGET AUDIENCES: The pathogenic yeast Candida albicans can affect individuals with compromised immune systems, such as cancer patients, AIDS patients, and the elderly. Identification of new potential anti-fungal drugs through this study may have a tremendous impact on these patient populations. PROJECT MODIFICATIONS: No major changes were made in this project.
Impacts
The goals of this research project were to examine the morphogenesis processes in the budding yeast Saccharomyces cerevisiae and the pathogenic yeast Candida albicans. We used genetic, molecular biology, and pharmacological experiments to identify small molecule inhibitors of morphogenesis in Candida albicans. We also used genetic experiments to analyze the subcellular localization of the Cdc24 protein, a major regulator of morphogenesis in Saccharomyces cerevisiae. In the course of these experiments, we identified 21 small organic molecules that inhibited morphogenesis in Candida albicans; we have extended these studies to determine if these molecules could be useful as potential anti-fungal drugs in the future.
Publications
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: The overall goal of our research is to characterize the mechanisms by which fungi in general, and the yeast Candida albicans in particular, cause disease and to identify new small organic molecules that can affect the virulence of C. albicans. The ability of C. albicans to cause disease is directly related to its ability to transition from a yeast-like budded growth state to a hyphal growth state, and to its ability to form recalcitrant biofilms on surfaces. The vast majority of bacteria and fungi exist in the biosphere in biofilm communities, and much of the pathogenicity of these microbes towards plants and animals is related to their ability to form these biofilms. We have characterized 23 small molecules that can inhibit the budded-to-hyphal transition (BHT) and these molecules also block the ability of C. albicans to form biofilms on polystyrene plates. In addition, we have shown that clinical C. albicans isolates obtained from FAHC have a variable ability to form biofilms in our assay. These data have been submitted for publication in the Journal of Medical Microbiology. In the future, two of these molecules, the receptor antagonist clozapine and the potential quorum sensing molecule ETYA, will be examined in more depth. PARTICIPANTS: This research was conducted by the Principal Investigator, Dr. Douglas Johnson, and by two talented UVM undergraduates, Jessica Pearson and Katelyn McLaughlin. Both Jessica and Katelyn received invaluable training in independent research approaches during this project. Jessica used these experiences to obtain a Laboratory Technician job in the UVM College of Medicine following her graduation. Katelyn is currently a UVM senior and will be graduating in May 2009. At least one additional UVM undergraduate will work on this project during the Spring 2009 academic semester. TARGET AUDIENCES: Fungal diseases cause significant crop damage as well as human suffering, especially to patients with compromised immune systems, such as those undergoing cancer chemotherapy or AIDS patients. The need for new anti-fungal drugs is immediate and critical and the 23 molecules we have identified and characterized may be good starting points for new anti-fungal therapeutics in the future. Data from these studies have been disseminated to the research community at UVM through several research seminars and have been submitted for publication in the Journal of Medical Microbiology. PROJECT MODIFICATIONS: No major changes or project modifications were needed.
Impacts
In our studies, we have identified 23 small molecules that can block the BHT in the pathogenic yeast C. albicans, with several also being able to block morphogenesis in the filamentous fungi Aspergillus fumigatus. These molecules can also block biofilm formation. We have also shown that some clinical C. albicans isolates obtained from FAHC can form biofilms on polystyrene plates but different species of Candida have variable effects in our assay. Fungal diseases of plants and animals are a major problem and new anti-fungal therapeutics are desperately needed. These 23 molecules, or bioactive derivatives, may be good starting points for new anti-fungal therapeutics in the future.
Publications
- No publications reported this period
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