Project Details
Description
Abstract
This application represents an approach to rational drug design for the treatment of microsporidiosis using
structure activity relationships (SAR) for agents that inhibit Methionine Aminopeptidase type 2 (MetAP2).
Microsporidiosis is an emerging zoonotic infection that is an opportunistic pathogen in the setting of AIDS, but
is also seen in other immune compromised hosts as well as immune competent hosts. Current therapies are
suboptimal. The hypothesis underlying this type of grant is that differences in the structure of the drug target
between host and pathogen will permit the design of selective therapeutic agents with decreased host toxicity.
The initial choice in drug design is the selection of the target among the dozens of potential targets. MetAP2 is
an extremely logical therapeutic target for these pathogens. Microsporidia lack Methionine Aminopeptidase
type 1 (MetAP1) making MetAP2 an essential enzyme. Among eukaryotes this makes them highly susceptible
to MetAP2 inhibitors and limits the toxicity of these compounds in their hosts as humans have both MetAP1
and MetAP2. Use of Fumagillin and its derivatives, which are non-competitive inhibitors that covalently bind to
and inhibit MetAP2 (but not MetAP1), has confirmed that inhibition of MetAP2 is an effective in vitro and in vivo
therapeutic target for many species of microsporidia. In fact, Fumagillin has been demonstrated to have
efficacy in humans infected with Enterocytozoon bieneusi; however, its use has been limited by bone marrow
toxicity. Our research group has cloned, expressed and determined the crystal structure of the MetAP2 of the
microsporidian Encephalitozoon cuniculi (i.e. EcMetAP2) as well as developed yeast dependent on EcMetAP2
for growth. We have identified and cloned Ent.bieneusi MetAP2 (EbMetAP2). Exploiting differences in the
structure of MetAP2 between host and pathogen should permit the design of selective therapeutic competitive
inhibitors of MetAP2 with decreased host toxicity. These new inhibitors will be tested in vitro and in vivo for
efficacy and in an iterative process we will use this information to refine our models and improve inhibitor
design. Using this Limited Rational Design (LRD) approach we will generate new libraries based on our lead
compounds that will then be modified to generate new libraries to improve their selectivity and pharmacologic
properties. We have already identified two lead compounds, BL6 and D63, from our initial LRD/SAR studies
that have increased selectivity for microsporidian MetAP2 and efficacy in our in vitro and in vivo models of
microsporidiosis. Since MetAP2 is important in other protozoa our lead compounds should also define new
classes of drugs that could have broad anti-parasitic activity and prove useful in the treatment of other
infections. Our assembled research group containing experts in medicinal chemistry, parasitology,
bioinformatics, mass spectrometry and structural biology as well as industry consultants has the necessary
complementary expertise to develop and test these compounds.
Status | Finished |
---|---|
Effective start/end date | 4/1/18 → 3/31/24 |
Funding
- National Institute of Allergy and Infectious Diseases: $401,250.00
- National Institute of Allergy and Infectious Diseases: $401,250.00
- National Institute of Allergy and Infectious Diseases: $414,750.00
- National Institute of Allergy and Infectious Diseases: $390,001.00
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