Our epithelial surfaces are normally resistant to infection. Therefore, researchers who study infectious disease commonly use of models that deliberately compromise the target tissue (or otherwise bypass barriers) so that disease can be enabled and studied. These infection models have led to a plethora of important information about factors involved in pathology and/or its resolution when disease is initiated. However, other models are needed to study barriers to infection, or early events that occur prior to disease initiation when it occurs in the absence of overt injury.
In our laboratory, we have developed novel in vivo and in vitro methods for studying defenses during health using the eye and the opportunistic bacterium Pseudomonas aeruginosa as models. We have also advanced imaging technologies that enable us to see into the living epithelium to observe what bacteria do and how the tissue responds in either resistant or susceptible states. Using these methods, and employing array/knockout/knockdown technologies, we have identified specific factors that modulate the ability of bacteria to penetrate the ocular surface epithelium. The data show that pathogen recognition systems are involved in resistance, and suggest that bacterial adaptation in vivo contributes to pathogenesis. Studies aimed at understanding early interactions between microbes and the ocular surface prior to disease initiation have potential for development of novel methods to prevent (rather than simply treat) infection of the eye or other sites.
UC Berkeley Vision Science, Molecular and Cell Biology: Why study the eye?
The lab is working on two inter-related goals.
1. To determine how the healthy corneal surface resists infection and how contact lens wear then compromises those defenses.
a) The laboratory’s long standing NIH (NEI) grant is aimed at understanding the molecular factors that prevent bacterial penetration of the corneal epithelium when the eye is healthy, how the functionality of that defense system is modulated, and the bacterial factors that enable penetration when the system is compromised. Barriers to our understanding in this area have included the lack of available in vivo models for studying these processes. Traditionally researchers have used “infection models” to study tissue interactions with bacteria. These involve deliberately compromising the tissue to induce enable susceptibility to infection, adding the microbe and then studying what happens next. Those who study corneal infection extensively use a scratch injury model that enables susceptibility by physically removing the epithelial barrier to expose the vulnerable stroma. Disease follows because direct placement of the microbe into the stroma stimulates a damaging inflammatory response.
This scratch injury model is problematic for the Fleiszig laboratory’s research goals for two reasons. Firstly, it bypasses the need for bacteria to penetrate the epithelium, which is the event the laboratory seeks to understand. Secondly, the lab is interested in understanding the events that determine health when the cornea is resistant to infection, not events that occur when there is disease. Due to the lack of suitable model systems, most of our knowledge about epithelial interactions with bacteria and the potential role of the epithelia in defense have necessarily come from cell culture studies.
Wild Type P. aeruginosa thrives in membrane blebs; type three secretion system mutants do not.
A. Angus, IAI, 2008
In the past 2 years, the laboratory has succeeded in developing multiple models (in vivo and in vitro) that enable epithelial cell penetration by bacteria to be studied. Together, these models provide the opportunity to do experiments either in the context of, or without, potentially confounding factors present in vivo, as is needed to test hypotheses. In the past year, the laboratory has also developed new imaging technologies that enable bacterial interactions with the epithelium to be imaged in living intact eyes without the need for any tissue dissection, staining, or other types of sample preparation/processing.
MyD88 is involved in corneal epithelium barrier function. C. Tam et al, PLoS ONE, 2011
b) A separate investigation to determine how the ocular surface retains its sterility was funded by a Grand Challenges Explorations Grant from the Gates Foundation. The long-term goal of this project is bold: To develop therapies to prevent any type of infection of any body site based on eye derived molecules.
2. Fundamental studies of bacterial/epithelial cell interactions using P. aeruginosa as a model organism.
The goal of this project is to determine how P. aeruginosa survive inside corneal epithelial cells, and the necessity for that strategy in the disease process. The data to date show that corneal epithelial cells normally traffic bacteria to intracellular vesicles where they are killed, but P. aeruginosa possesses virulence factors that enable it to bypass this innate defense. Experimental approaches involving biochemical and genetic methods, combined with various images techniques, are being used to describe the details of the intimate interactions between P. aeruginosa and eukaryotic cells. The results will enlighten us about how bacteria cause disease and should also contribute to our understanding of epithelial cell biology.
P. aeruginosa causes sight threatening pathology in the eye and life threatening infections at other sites. These include serious lung disease in children with cystic fibrosis and in AIDS patients, and life theatening skin infections in burns victims. Thus, this line of research could ultimately lead to new means for treating multiple diseases.
Inside Science Feature, Killer Eyes: Stopping Infections
|Suzanne Fleiszig, OD, PhD
|Honors and Awards
|David Evans, PhD
|David’s Touro University faculty page|
|Matteo Metruccio, PhD
Staff Research Associate
|Abby Kroken, PhD
|Vincent Nieto, PhD
|Melinda Grosser, PhD
|Si Jie Ma
PublicationsView on Pubmed
Professor Suzanne Fleiszig
School of Optometry
688 Minor Hall
Office: (510) 643-0990
Lab: (510) 642-0511
Fax: (510) 643-5109
Our records are incomplete! If you're not listed, or would like to provide a website or Linked In profile, please email arkroken(at)berkeley.edu and we will update this page!
|Jianfang Li, PhD||Postdoctoral Fellow, 2014-2017, The International Postdoctoral Exchange Fellowship from China Postdoctoral Council, 2014-2016||Linked In|
|Justin Duong-Mac||Optometry Student Researcher, 2017|
|Sarah Alsamman||URAP Student, 2015-2017, SURF L&S Fellow, 2016|
|Aaron Sullivan, MS, PhD||Graduate Student, 2011-2015, Postdoc 2015-2016||Linked In|
|Anna Xie||Optometry Student Researcher, 2015-2016||Linked In|
|Julio Martinez||Pre-doctoral Scholar, Sally Casanova Scholarship 2015-2016||Angeline Truong||High School Student Volunteer, 2015-2016|
||URAP Student, 2016|
||Administrative Staff, 2013-2015||Linked In|
||Administrative Staff, 2013-2015||Linked In|
|Anthony Del Cid
||Undergraduate researcher (UC Santa Cruz), 2015|
||Optometry Student Researcher, 2015||Linked In|
|Amber Jolly, PhD||Postdoc (T32 Fellow), 2012-2015||Linked In|
||URAP Student, 2014-2015, Rose Hills Fellow, 2015|
||URAP Student, 2014-2015|
||URAP Student, 2014-2015|
|TY Yvonne Wu, OD MPH PhD
||Postdoc Fellow, 2012-2014||Linked In|
||URAP Student, 2012-2014||Linked In|
|KP Connie Tam, PhD
||Postdoc, Assistant Researcher|
|Victoria Hritonenko, PhD
||Postdoc (NRSA fellow)||Linked In|
|Susan Heimer, PhD
||Visiting Scholar, 2009-2013||Linked In|
|Desire Takawira, PhD
|James Mun, PhD
||Graduate Student, 2005-2011|
|Victoria Tran, PhD
||Graduate Student, 2007-2011|
|Danielle Augustin, PhD
||Graduate Student, 2007-2011 (NRSA fellow 2009-2011)||Linked In|
|Julio Ramirez, PhD
||Staff Research Associate, 2009-2010|
|Annette A Angus, PhD
||Graduate Student, 2004-2009||Linked In|
|Sarah Lewis, OD
||Staff Research Associate, 2005-2009|
|Amanda Ackerman Lee, MA, MPH
||Graduate Student, 2004-2008|
|Irania Alaracon, MS, PhD
||Graduate Student, 2003-2007|
|Inna Maltseva, OD, PhD
||Graduate Student, 2000-2005, Optometry Student, 1996-1999||Linked In|
|Minjian Ni, Ph.D
|Carol Lakkis, BScOptom, PhD,||Visiting Scholar, 1996-1997, Assistant Researcher, 2001-2002||Linked In|
Research in the Fleiszig Lab is funded by the following foundations: