Laura Okagaki

E-mail: okag0004@umn.edu

Year entered: 2007

Thesis Advisor: Kirsten Nielsen

Degree received:
Bachelor of Fine Arts, Photography, Minneapolis College of Art and Design, 1999
B.S., Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 2006

Honors and Awards:

• Graduate School Block Fellowship, Fall Semester 2007
• Genetics Society of America Poster Award 2009
• Outstanding Young Investigator Award, American Society for Microbiology 2009
• Accepted into Molecular Mycology at the Marine Biology Laboratory, Woods Hole, MA

Thesis Research:

Cryptococcus neoformans is an opportunistic human fungal pathogen that afflicts immunocompromised individuals such as advanced HIV/AIDS patients. This encapsulated fungus is commonly found in the environment, however, when inhaled can cause acute lung infection and dissemination to the brain causing meningitis. There are two varieties of Cryptococcus neoformans var. grubii and var. neoformans. Of these two serotypes, var. grubii is far more virulent, accounting for as many as 95% of cryptococcal infections worldwide. There are two mating types in Cryptococcus: a and alpha. When mice are experimentally infected intranasally with either var. grubii a or alpha alone, they exhibit similar disease progression. However, in mice infected with both a and alpha mating types simultaneously, a higher proportion of alpha cells are able to disseminate to the brain while equivalent numbers of a and alpha cells are found in peripheral tissues. Examination of lung tissue reveals a subset of cells that are 5 to 10 fold larger than the typical cell size. This observed cell enlargement is enhanced in coinfections - suggesting pheromone signaling may be involved in generation of large cells. Differential staining revealed a significantly higher proportion of enlarged mating type a cells during coinfection. We have termed these enlarged cells titan cells. My current work focuses on the identifying the molecular mechanisms and signaling pathways involved in titan cell production in C. neoformans var. grubii. Additionally, I am working to determine the virulence of titan cells and their potential role in establishment and persistence of cryptococcal infections.