There is increasing evidence that the mosquito midgut mounts immune responses to the malaria parasite during invasion. However, the ookinete is able to survive these responses to eventually be transmitted to the vertebrate host. The general goal of this proposal is to gain new insight into the mechanisms involved in this process. We propose to study the activation of two immuno-regulatory pathways in the midgut and fat body. Electrophoretic mobility shift assays (EMSA) will be used to follow the induction of DNA binding activity to STAT-like and NF-kappaB-like target sequences. Our preliminary experiments indicate that the midgut is the main organ activating the JAK-STAT pathway in response to malaria infection. The time course of these responses will be also analyzed. We will study the midgut epithelium immune responses to ookinete invasion at the cellular level by analyzing the pattern of expression, sub-cellular localization and the induction of different immune markers by immunocytochemistry. We will determine if genes known to be induced by malaria infection are regulated by the JAK-STAT pathway. A cDNA subtraction strategy is proposed to isolate new malaria inducible genes. Recent Southern blot analysis of Ag-STAT BAC clones suggests that a new STAT family member is located in close physical proximity to Ag-STAT. We will attempt to characterize and study this new gene. Establishing which cells are invaded by the ookinete and the molecular nature of their responses is central to understanding the survival strategy of the parasite.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI045573-01A1
Application #
6095862
Study Section
Special Emphasis Panel (ZRG1-TMP (01))
Program Officer
Aultman, Kathryn S
Project Start
2000-04-01
Project End
2004-03-31
Budget Start
2000-04-01
Budget End
2001-03-31
Support Year
1
Fiscal Year
2000
Total Cost
$251,500
Indirect Cost
Name
Colorado State University-Fort Collins
Department
Microbiology/Immun/Virology
Type
Schools of Veterinary Medicine
DUNS #
112617480
City
Fort Collins
State
CO
Country
United States
Zip Code
80523
Ramirez, Jose Luis; Garver, Lindsey S; Brayner, Fábio André et al. (2014) The role of hemocytes in Anopheles gambiae antiplasmodial immunity. J Innate Immun 6:119-28
Kumar, Sanjeev; Barillas-Mury, Carolina (2005) Ookinete-induced midgut peroxidases detonate the time bomb in anopheline mosquitoes. Insect Biochem Mol Biol 35:721-7
Kumar, Sanjeev; Gupta, Lalita; Han, Yeon Soo et al. (2004) Inducible peroxidases mediate nitration of anopheles midgut cells undergoing apoptosis in response to Plasmodium invasion. J Biol Chem 279:53475-82
Kumar, Sanjeev; Christophides, George K; Cantera, Rafael et al. (2003) The role of reactive oxygen species on Plasmodium melanotic encapsulation in Anopheles gambiae. Proc Natl Acad Sci U S A 100:14139-44