TRYPANOSOMA CRUZI: PATHOGENESIS OF INFECTION

  • Tanowitz, Herbert B. (PI)

Project: Research project

Project Details

Description

DESCRIPTION (Adapted from the Applicant's Abstract): A major advance has been
the understanding of the role of both endothelin-I (ET-]) and NF-KappaB in the
pathogenesis of chagasic vasculopathy. We propose to focus on molecular,
cellular, and tissue level studies of how the parasite causes vascular
pathology. Two pathogenic pathways will be investigated,
vasoconstriction/ischemia and inflammation. T. cruzi infection of the cells of
the vascular endothelium modulates vessel tone by increasing the synthesis of
the vasoactive peptide, ET- I causing vascular spasm and myocardial ischemia.
The NIAPK cascades regulate AP-1 activation resulting in ET-1 expression. We
will determine which kinase cascade (Raf-ERK or MEKK-JNK) is dominant in
regulating the activation of AP-1 in endothelial cells. The methods to be used
include small G-protein guanidine nucleotide assays and NIAPK activity assays.
We will co-transfect dominant negative genes of the kinase cascades with AP-I
and ET-I reporter genes to delineate the activation of pathways. Since the MAPK
cascade also contributes to smooth muscle proliferation and vascular remodeling
of damaged vessels we plan to examine the consequences of T. cruzi infection on
NIAPKs in these cells by exposure to supernatants of infected endothelial
cells. In addition, we will examine the effect of T. cruzi infection on the
activation of the MAPKS, AP-I and ET-I expression in the vasculature and
myocardium of mice. The role of ET-I in the pathogenesis of chagasic heart
disease will be investigated by infecting mice in which ET-l has been deleted
in vascular endothelial cells and cardiac myocytes. The pathophysiological
consequences of infection on myocardial structure and function will be
evaluated by invasive and non-invasive methods. Infection of endothelial cells
with T. cruzi induces expression of cytokines, adhesion molecules, leading to
inflammation and pathology. We hypothesize that an important mechanism
responsible for myocardial inflammation is activation of the vasculature
NF-KappaB pathway. Accordingly, we will examine the mechanism by which T. cruzi
activates the NF-KappaB pathway in endothelial and vascular smooth muscle cells
by investigating the role of the generation of reactive oxygen species and
cytoplasmic phospholipase A2 activity. We will also employ co-transfection of
dominant negative genes of the kinase cascade with NF-KappaB reporter to define
the pathway. Finally, we plan to examine the consequences of T. cruzi infection
on the activation of NF-KappaB and the outcome of ROS inhibitors in vivo. These
studies will delineate the mechanisms by which T. cruzi causes vasculopathy
leading to cardiomyopathy.
StatusFinished
Effective start/end date1/1/901/31/05

Funding

  • National Institute of Allergy and Infectious Diseases: $417,500.00

Fingerprint

Explore the research topics touched on by this project. These labels are generated based on the underlying awards/grants. Together they form a unique fingerprint.