Live Imaging of Host-Parasite Interactions in a Zebrafish Infection Model Reveals Cryptococcal Determinants of Virulence and Central Nervous System Invasion.

Tenor, Jennifer L

Oehlers, Stefan H

Yang, Jialu L

Tobin, David M

Perfect, John R

Chiller, Tom

United States

2015-12-15T16:37:53Z

2015-09-29

UNLABELLED: The human fungal pathogen Cryptococcus neoformans is capable of infecting a broad range of hosts, from invertebrates like amoebas and nematodes to standard vertebrate models such as mice and rabbits. Here we have taken advantage of a zebrafish model to investigate host-pathogen interactions of Cryptococcus with the zebrafish innate immune system, which shares a highly conserved framework with that of mammals. Through live-imaging observations and genetic knockdown, we establish that macrophages are the primary immune cells responsible for responding to and containing acute cryptococcal infections. By interrogating survival and cryptococcal burden following infection with a panel of Cryptococcus mutants, we find that virulence factors initially identified as important in causing disease in mice are also necessary for pathogenesis in zebrafish larvae. Live imaging of the cranial blood vessels of infected larvae reveals that C. neoformans is able to penetrate the zebrafish brain following intravenous infection. By studying a C. neoformans FNX1 gene mutant, we find that blood-brain barrier invasion is dependent on a known cryptococcal invasion-promoting pathway previously identified in a murine model of central nervous system invasion. The zebrafish-C. neoformans platform provides a visually and genetically accessible vertebrate model system for cryptococcal pathogenesis with many of the advantages of small invertebrates. This model is well suited for higher-throughput screening of mutants, mechanistic dissection of cryptococcal pathogenesis in live animals, and use in the evaluation of therapeutic agents. IMPORTANCE: Cryptococcus neoformans is an important opportunistic pathogen that is estimated to be responsible for more than 600,000 deaths worldwide annually. Existing mammalian models of cryptococcal pathogenesis are costly, and the analysis of important pathogenic processes such as meningitis is laborious and remains a challenge to visualize. Conversely, although invertebrate models of cryptococcal infection allow high-throughput assays, they fail to replicate the anatomical complexity found in vertebrates and, specifically, cryptococcal stages of disease. Here we have utilized larval zebrafish as a platform that overcomes many of these limitations. We demonstrate that the pathogenesis of C. neoformans infection in zebrafish involves factors identical to those in mammalian and invertebrate infections. We then utilize the live-imaging capacity of zebrafish larvae to follow the progression of cryptococcal infection in real time and establish a relevant model of the critical central nervous system infection phase of disease in a nonmammalian model.

http://www.ncbi.nlm.nih.gov/pubmed/26419880

mBio.01425-15

2150-7511

https://hdl.handle.net/10161/11177

eng

American Society for Microbiology

MBio

10.1128/mBio.01425-15

Animals

Central Nervous System

Cryptococcosis

Cryptococcus neoformans

DNA Mutational Analysis

Disease Models, Animal

Gene Knockdown Techniques

Host-Parasite Interactions

Larva

Macrophages

Optical Imaging

Survival Analysis

Virulence

Virulence Factors

Zebrafish

Live Imaging of Host-Parasite Interactions in a Zebrafish Infection Model Reveals Cryptococcal Determinants of Virulence and Central Nervous System Invasion.

Journal article

Tobin, David M|0000-0003-3465-5518

Perfect, John R|0000-0002-6606-9460|0000-0003-3465-5518

http://www.ncbi.nlm.nih.gov/pubmed/26419880

e01425

e01415

5

Basic Science Departments

Clinical Science Departments

Duke

Immunology

Medicine

Medicine, Infectious Diseases

Molecular Genetics and Microbiology

School of Medicine

Published online

6