PROJECT SUMMARY/ABSTRACT
The worst outcome of infection with Plasmodium falciparum is death from Cerebral Malaria (CM). An
estimated 445,000 people, mostly children, die yearly from CM and survivors often experience long-
term neurological sequelae. The host response to infection causes encephalopathy. However, the
causes of pathology are multi-factorial, and not well-defined, limiting development of strategies to treat
patients and reduce mortality. Severe vascular congestion, coagulation, and increased inflammatory
cytokines each correlate with poor CM outcomes. Mutations that promote low levels of the regulatory
cytokine, IL-10, in response to parasite correlate with more severe disease, as do low serum levels.
While both parasite and host variation are likely to contribute to pathogenesis, it is challenging to
separate them experimentally. Therefore, we employ a model of hyper-inflammatory experimental CM
(eCM), which is due to a normally non-virulent parasite strain that is not found sequestered in the brain,
and yet causes many of the symptoms of CM in a hyper-inflammatory setting (IL-10 KO). This model, in
combination with anti-coagulants, will allow us to examine the role of inflammatory cytokines and
coagulation in a reductionist manner. In preliminary data, we found that hyper-inflammation drives
formation of thrombi in the brain vasculature that contain inflammatory leukocytes. Furthermore,
activated glia are attracted to these thrombotic sites suggesting amplification of inflammatory cytokines
within or associated with these vascular foci. Strikingly, treatment with anti-coagulant resulted in
reduced mortality from eCM, as well as reduced gliosis and behavioral symptoms. Therefore, we
hypothesize that thrombus-associated events promote cytokine amplification and neuropathology, either by
trapping immune cells, which interact within the vasculature, or by direct activation of glia, by fibrin(ogen)
leaked from the site of thrombosis. We will determine the mechanisms of thrombus-associated
neuropathology through the following specific aims: 1) Determine the pathogenic effects of thrombi and
inflammatory cells on intravascular events in hyperinflammatory experimental Cerebral Malaria and 2)
Determine mechanisms of Fibrinogen-driven neuropathology in malaria infection. This study will dissect the
complimentary and overlapping mechanisms by which fibrin(ogen) contributes to inflammation and
neuropathology in cerebral malaria. Understanding the interactions between inflammation and
coagulation promoting neuropathology in eCM will drive identification of critical factors involved in
cerebral pathology leading to potential therapeutic strategies in the future. The three collaborating
investigators bring a cohesive team with complimentary knowledge and skills: immunology of malaria,
neuroimmunology and cutting-edge imaging of the brain, to this multi-disciplinary project which will
improve our understanding of this lethal multi-factorial disease.