Medical Research Centers

24 Jan Genes Identified That May Predispose Some Individuals to Getting Sick

[caption id="attachment_20931" align="alignleft" width="200"] Dr. Ephraim Tsalik
Duke Health[/caption] MedicalResearch.com Interview with: Ephraim L. Tsalik, MD MHS PhD Assistant Professor of Medicine Division of Infectious Diseases Center for Applied Genomics & Precision Medicine Duke University Medical Center Emergency Department Service Line Durham VA Medical Center  Medical Research: What is the background for this study? What are the main findings? Dr. Tsalik: This study was motivated by the convergence of two research interests.  The first was spearheaded by Dr. Sack, leading our collaboration at Johns Hopkins.  Dr. Sack and his colleagues have a long history and expertise in studying enteric infections such as E. coli.  The second is our group here at Duke’s Center for Applied Genomics & Precision Medicine as well as the Durham VA Medical Center.  Specifically, we have an interest in studying the host response to infectious disease.  One of the ways we’ve done that historically is through challenge studies where healthy volunteers are exposed to a pathogen in a controlled setting.  Despite everyone getting the same exposure, not everyone gets sick.  That observation gives us a unique opportunity to study the host biology of symptomatic individuals, asymptomatic individuals, and what distinguishes the two from each other.  That is precisely what we did here. Volunteers ingested Enterotoxigenic E. coli (ETEC), which is a common cause of traveler’s diarrhea.  Some subjects became ill with diarrhea while others remained well.  In this study, we focused on gene expression patterns, which is a snapshot of how genes in the body are being used in response to this infection.  Some genes are more active, some are less.  The pattern of those changes that occur in response to infection is what we call a “signature”. This approach allowed us to generate some key findings.  First of all, we were able to define the genes involved in the body’s response to this type of E. coli infection.  Second, we discovered genes that were differentially expressed at baseline that could distinguish people who would go on to become ill from those that would remain healthy.  Although this study was not designed to identify the mechanism for that resilience to infection, it does focus our attention on where to look.  We suspect the genes we identified are likely to play a role in infectious disease resilience and susceptibility based on their known immune function roles.  We also have data, which wasn’t published in this study, that implicates some of these genes in the resilience to other infections such as influenza. The last major finding was something called Drug Repositioning Analysis.  This is a tool that allowed us to identify drugs and drug classes that could be used to mitigate infections caused by ETEC.  That analysis highlighted some compounds already known to be effective such as Zinc.  But it also identified several other drug classes that have not previously been investigated and could be important tools to combat such infections especially as antibiotic resistance looms.