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David Sherman, Ph.D.
Mission
Dr. Sherman's work is focused on tuberculosis
(TB) virulence and drug discovery. TB takes at
least six months to treat, and the bacterium
responsible has developed widespread resistance
to the currently available drugs, so there is a
great need for new therapies.
Research
With about one-third of the world population infected and two million deaths
annually, Mycobacterium tuberculosis is unquestionably one of the world's
most successful human pathogens. The Sherman laboratory studies the bacterial
and host strategies that underpin this success. Dr. Sherman is especially
interested in two formerly intractable areas of M. tuberculosis biology:
virulence and dormancy.
Since roughly two billion people are infected with M.
tuberculosis worldwide but only about 1% of those people have active
disease, factors that alter the balance between latency and illness are of great
interest. Dormant M. tuberculosis is thought to be associated with
microaerophilic environments in the host, but current models to test this idea
are inadequate. To address this situation, the Sherman lab has developed methods
to maintain M. tuberculosis for extended periods in defined
microaerophilic environments. Using this system, lab members have shown that the
mycobacterial transcription factor DosR responds to a drop in oxygen tension by
inducing expression of about 50 genes – the DosR regulon. They are performing
detailed molecular characterization of hypoxic signal transduction and DosR
activation.
The Sherman lab is also engaged in detailed analyses of
M. tuberculosis gene expression in vitro and in vivo, and have
developed a novel approach to study bacterial replication rate during infection.
Lab members maintain a longstanding interest in what the TB vaccine BCG and
other attenuated mutants can reveal about mycobacterial virulence. The lab is
also interested in why TB treatment requires at least six months of
chemotherapy.
The Sherman lab also focuses on novel assays and targets for
much-improved anti-TB drugs and on understanding drug tolerance. Lab members
routinely employ a variety of research tools, including molecular genetics
(targeted gene disruption, representational difference analysis, TraSH),
biochemistry, cultivation in vitro, in macrophages and in various animal
models, and whole genome microarray analysis.
Themes
* TB virulence and dormancy
* Drug resistance and drug tolerance
* Development of new TB drugs
Accomplishments
* Helped to define the molecular and
biochemical response of M. tuberculosis to oxidative stress and to drugs
such as isoniazid
* Developed methods to maintain M.
tuberculosis for extended periods in defined microaerophilic environments.
* Identified and characterized the M.
tuberculosis response to reduced oxygen tension.
* Defined and characterized the molecular lesion
responsible for attenuation of the TB vaccine, M. bovis BCG, which has been
given to billions of people worldwide.
Collaborations
* University of Washington
* Harvard University
* National Institutes of Health
* Stanford University
* Imperial College, London
* University of Witwatersrand, Johannesburg
Support for Dr. Sherman’s work is
provided by the National Institutes of Health and by the Bill and Melinda Gates
Foundation.
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