Candida Invasion of Endothelium and Virulence Abstract The incidence of bloodstream infections caused by Candida species has increased dramatically; these organisms now account for 10% of all bloodstream isolates. The mortality associated with candidemia approaches 40%, even with therapy. Because of this unacceptably high mortality, new strategies to treat and prevent this infection are necessary. Our goal is to identify new Candida albicans virulence genes and to determine the mechanisms by which they contribute to pathogenicity. This information holds promise to identify new targets for antifungal strategies. Our hypothesis is that the ability of C. albicans to invade and damage host cells, while avoiding host defense mechanisms, is critical for the organism to establish and maintain a deep- seated infection. Support for this hypothesis comes from our finding that many C. albicans mutants with reduced capacity to invade and damage endothelial cells in vitro also have decreased virulence in the mouse model of hematogenously disseminated infection. Our objective is to use in vitro studies of the interactions between C. albicans and vascular endothelial cells to define mechanisms of host- pathogen interaction. C. albicans invades endothelial cells by inducing its own endocytosis. In the previous project period, we discovered that C. albicans Als3 is an invasin that binds to N-cadherin on the endothelial cell surface and induces the endocytosis of the organism. Recently, we have determined that there are additional C. albicans invasins and endothelial cell surface proteins that mediate endocytosis. These surface proteins include AHNAK and ErbB2. In this project, we will 1) determine the interactions among AHNAK, N-cadherin, and ErbB2 in endothelial cell invasion by C. albicans;2) determine the mechanisms by which C. albicans Ssa1 contributes to endothelial cell invasion and virulence;3) use C. albicans mutants to elucidate functional relationships among C. albicans virulence regulators, endothelial cell receptors, and endothelial cell damage.

Public Health Relevance

Project Relevance / Narrative This research is highly relevant to public health because hematogenously disseminated candidiasis is common in hospitalized patients and still causes significant mortality, even with currently available treatment. Discovering C. albicans genes and host cell receptors that govern endothelial cell invasion and damage holds promise to provide new insight into the pathogenesis of disseminated candidiasis. Furthermore, this information may be used to develop new diagnostic or therapeutic strategies against this frequently fatal disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI054928-10
Application #
8414865
Study Section
Pathogenic Eukaryotes Study Section (PTHE)
Program Officer
Duncan, Rory A
Project Start
2003-04-01
Project End
2014-12-31
Budget Start
2013-01-01
Budget End
2014-12-31
Support Year
10
Fiscal Year
2013
Total Cost
$258,453
Indirect Cost
$48,766
Name
La Biomed Research Institute/ Harbor UCLA Medical Center
Department
Type
DUNS #
069926962
City
Torrance
State
CA
Country
United States
Zip Code
90502
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Shankar, Jyoti; Solis, Norma V; Mounaud, Stephanie et al. (2015) Using Bayesian modelling to investigate factors governing antibiotic-induced Candida albicans colonization of the GI tract. Sci Rep 5:8131
Xu, Wenjie; Solis, Norma V; Ehrlich, Rachel L et al. (2015) Activation and alliance of regulatory pathways in C. albicans during mammalian infection. PLoS Biol 13:e1002076
Liu, Yaoping; Solis, Norma V; Heilmann, Clemens J et al. (2014) Role of retrograde trafficking in stress response, host cell interactions, and virulence of Candida albicans. Eukaryot Cell 13:279-87
Sheppard, Donald C; Filler, Scott G (2014) Host cell invasion by medically important fungi. Cold Spring Harb Perspect Med 5:a019687

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