Malaria remains a major cause of illness and death worldwide. Two major unresolved issues concerning the pathogenesis of malaria are: 1) what molecules from the parasite activate the innate immune system and cause inflammation and, 2) what are the receptors that are ligated by these microbial products. The overall goal of this project is to identify the molecular mechanisms of systemic inflammation and fever in individuals infected with Plasmodium falciparum. Our preliminary data demonstrate that malaria DNA, especially when complexed to the malarial pigment hemozoin, activates inflammation. The underlying HYPOTHESIS of this proposal is that fever and inflammation in acute malaria are initiated by the interaction of malarial DNA with DNA receptors expressed by phagocytes. We further hypothesize that the innate immune response to malarial DNA is mediated by two receptors: TLR9 and an as yet unidentified receptor for AT-rich DNA motifs. This hypothesis challenges the concept that malarial glycosylphosphatidylinositol (GPI)-lipid anchors, which are primarily TLR2/CD14 agonists, are the primary cause of systemic inflammation in malaria. In order to test this hypothesis, we propose to combine an examination of immune activation in cells from patients with acute febrile malaria with in vitro work. We propose three Aims.
The first Aim i s to determine if innate immune activation induced by malaria, occurs primarily in TLR9+ cells, or in cells that primarily express TLR2 and/or CD14. We will profile gene induction in purified cells with defined TLR expression in culture and from patients in order to determine which receptors and signaling pathways are employed. DNA, and oligonucleotides derived from the malarial genome, will be compared to purified malarial GPI anchors. In our second Aim, we will assess the importance of hemozoin in inflammation. PBMC will be collected from malaria patients, sorted into hemozoin positive and negative monocytes and DCs, and assessed for markers of immune activation. We will perform confocal imaging studies of hemozoin and malarial DNA trafficking in immune cells. These studies will determine the temperospatial relationships between trafficking and innate immune responses, including the engagement of specific DNA receptors and the activation of the inflammasome. In the final Aim, we will focus on the immune activity of AT-rich oligonucleotides whose sequences are derived from the malarial genome. We will focus on;1) those signaling pathways that result in the production of Type I interferons, which we have found to be a critical determinant of outcome in mouse cerebral malaria;and 2) activation of the inflammasome, primarily through NRLP3 and AIM2, an inflammasome component that we recently discovered. Signaling pathways will be established using both a molecular genetics approach and the use of proteomics. We will test inflammasome knockout mice, including a new AIM2 KO, in mouse cerebral malaria, thus relating our in vitro findings with in vivo disease. Our ultimate goal is to define the relative role of malarial DNA in mediating innate immune responses during malarial infection and to definitively identify related DNA receptors.

Public Health Relevance

Malaria is the world's most common infectious disease, and kills millions of individuals annually. US citizens risk obtaining malaria when they travel or are engaged in military operations in tropical areas. The purpose of this grant is to gain a better understanding of why malaria causes disease in the hopes that better therapies can be devised, including an effective vaccine that might prevent malaria.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
Project #
Application #
Study Section
Immunity and Host Defense Study Section (IHD)
Program Officer
Wali, Tonu M
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Massachusetts Medical School Worcester
Internal Medicine/Medicine
Schools of Medicine
United States
Zip Code
Andrade, Warrison A; Agarwal, Sarika; Mo, Shunyan et al. (2016) Type I Interferon Induction by Neisseria gonorrhoeae: Dual Requirement of Cyclic GMP-AMP Synthase and Toll-like Receptor 4. Cell Rep 15:2438-48
Rathinam, Vijay A K; Fitzgerald, Katherine A (2016) Inflammasome Complexes: Emerging Mechanisms and Effector Functions. Cell 165:792-800
Hirako, Isabella C; Ataide, Marco A; Faustino, Lucas et al. (2016) Splenic differentiation and emergence of CCR5(+)CXCL9(+)CXCL10(+) monocyte-derived dendritic cells in the brain during cerebral malaria. Nat Commun 7:13277
Hirako, Isabella C; Gallego-Marin, Carolina; Ataide, Marco A et al. (2015) DNA-Containing Immunocomplexes Promote Inflammasome Assembly and Release of Pyrogenic Cytokines by CD14+ CD16+ CD64high CD32low Inflammatory Monocytes from Malaria Patients. MBio 6:e01605-15
Rocha, Bruno Coelho; Marques, Pedro Elias; Leoratti, Fabiana Maria de Souza et al. (2015) Type I Interferon Transcriptional Signature in Neutrophils and Low-Density Granulocytes Are Associated with Tissue Damage in Malaria. Cell Rep 13:2829-2841
Corbett, Yolanda; Parapini, Silvia; D'Alessandro, Sarah et al. (2015) Involvement of Nod2 in the innate immune response elicited by malarial pigment hemozoin. Microbes Infect 17:184-94
Chan, Jennie; Atianand, Maninjay; Jiang, Zhaozhao et al. (2015) Cutting Edge: A Natural Antisense Transcript, AS-IL1?, Controls Inducible Transcription of the Proinflammatory Cytokine IL-1?. J Immunol 195:1359-63
Liehl, Peter; Zuzarte-Luís, Vanessa; Chan, Jennie et al. (2014) Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection. Nat Med 20:47-53
de Oliveira, Rosane B; Wang, Jennifer P; Ram, Sanjay et al. (2014) Increased survival in B-cell-deficient mice during experimental cerebral malaria suggests a role for circulating immune complexes. MBio 5:e00949-14
Antonelli, Lis R V; Leoratti, Fabiana M S; Costa, Pedro A C et al. (2014) The CD14+CD16+ inflammatory monocyte subset displays increased mitochondrial activity and effector function during acute Plasmodium vivax malaria. PLoS Pathog 10:e1004393

Showing the most recent 10 out of 22 publications