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Understanding Macrophage Defense Strategies




Catherine (Katie) Brennan (CSU Fullerton, 2013 New Investigator, 2016 New Investigator, 2016 Travel Grant) is an immunologist interested in the fundamental processes used by blood cells to protect themselves, as well as the entire organism, from infection. 

She explains her fascination with this science this way: "On those rare occasions when a macrophage [a white blood cell type] encounters a microbe that has managed to breach the external barrier defenses, it is a real emergency, both for the cell and the whole organism. The macrophage changes completely, in a manner of minutes.  Not only does it engulf the microbe and initiate killing mechanisms, but its whole metabolism is rapidly rewired, it releases alarm signals to alert other tissues, and it may migrate to a central organ for reasons we don't fully understand - all facets of inflammation." Her lab uses Drosophila (fruit fly) as a model organism "to discover and analyze these really fundamental cell biological questions, using the arsenal of genetic approaches that generations of scientists have developed… Inflammation is a double-edged sword, essential during infection, but harmful if it becomes a chronic state, such as in cancer, diabetes, and atherosclerosis. I am fascinated by the similarities we are finding between inflammatory processes in flies and in humans, and think we can learn a lot from flies in how to keep inflammation in its place."

When Dr. Brennan joined the faculty at CSU Fullerton she "was making a big change in my research field. I had studied the genetics of fly immunity in the early 2000's, but then had a long hiatus, during which time I conducted HIV research and also taught high school. It took me a little while to find my feet in this new field of macrophage cell biology, and the research support and teaching release from the two CSUPERB [New Investigator] grants helped enormously." The in-depth research experiences offered in the Brennan lab also launched the careers of the two students supported by the CSUPERB grant: Eniola Ogundipe and Nuzhat Islam. Ms. Ogundipe is now in medical school at the University of Colorado; Ms. Islam enters medical school at University of California San Francisco this fall. Both intend to pursue research as well as clinical studies.

CSUPERB-supported faculty members often tell us that travel grants are immeasurably important to their research and career trajectories. Dr. Brennan explains, "The Sicily meeting was very valuable…just hearing from so many researchers about their work in mammalian macrophage biology. It also led directly to an invitation to a small Woods Hole Symposium on fly macrophages a month later, where I spoke about our work, and initiated lots of important collaborations.  One of these collaborations resulted in a paper that just came out… I've also been invited to the follow-up to the Woods Hole meeting that is taking place in Vienna…I went there [Sicily] not really knowing anyone, and was a little nervous, but I am still experiencing the incredibly positive cascade of consequences of that Sicily meeting – it just opened so many doors, that led to other doors, etc…"

All the preliminary work, collaborations, and learning paid off; Dr. Brennan's lab received NIH funding in 2017. When asked how the funding will change her group, she explains, it "can really accelerate the pace of discovery. I also have much more time to meet with my research students to analyze their data, and bring a second pair of eyes towards thinking about significance and troubleshooting. Also, it has given me more time to write manuscripts [and] I've been able to afford some invaluable reagents that would have been out of reach, financially, before."

After her training in research-intensive settings at Sloan-Kettering Institute, Stanford and UCLA, Dr. Brennan says there are many things to love about her position at CSU Fullerton. "I love the breadth among my colleagues, from marine biology to ornithology to computational biology – you just don't get that breadth in a medical research institute. I really appreciate the emphasis on teaching quality – it is something I put a lot of time and effort into, and it's really nice to have that valued by my department. Also, having the teaching be a big part of the job means that my salary is not dependent on grants, which can be a very stressful way to live. I like being part of an institution where we want our students to succeed; in other places, introductory science courses are explicitly set up to weed out students, which I would find very discouraging. Finally – the students! Overall, most of them are here to learn, and are curious and motivated, and a lot of fun to teach."

Park, S-H, Lee, C-W,  Lee, J-H, Park, JY, Roshandell, M, Brennan, CA & Choe K-M (2018) Requirement for and polarized localization of integrin proteins during Drosophila wound closure. Molecular Biology of the Cell


Photo Captions (photos below, left to right)

1. CSU Fullerton undergraduates Eniola Ogundipe and Kristofer Serrano presenting their work at the Annual Drosophila Research Conference.

2. Graduate student Amber Myers sorts flies for genetic crosses.

3. CSU Fullerton undergraduate Martin Arreola prepares samples for PCR in the Brennan lab.

4. CSU Fullerton graduate student Caitlin Harris examines some phagocytosis samples by live fluorescence microscopy.


This story is one in a series of PI profiles published in concert with the AY 17-18 CSUPERB Annual Report. Read the report here and find other profiles here.