|
My work focuses on how host cells recognize and respond to Gram-negative bacterial-derived endotoxin (E). Host response to E depends on the ordered interaction of four host proteins: LBP, CD14, MD-2 and Toll-Like Receptor 4 (TLR4). Previous work has shown that monomeric E is extracted by CD14 in the presence of LBP, forming E:CD14. The E monomer is then transferred to MD-2 forming E:MD-2, which binds to TLR4 and triggers an intracellular signaling cascade. Signaling through TLR4 can proceed through the MyD88-dependent pathway, which involves the interaction of the intracellular mediators MyD88 and MAL, or through the TRIF-dependent pathway, which involves the intracellular mediators TRIF and TRAM. I am investigating the molecular requirements for activation of these pathways, and how the activation of a specific TLR4 signaling cascade can modulate the immune response and affect the overall outcome of infection. Currently I am utilizing the transformed human astrocytoma cell line U373 that expresses TLR4/MD-2 in the absence of CD14 to determine if CD14 is required for TRIF-dependent signaling in human cells. Our lab also has access to wild-type C57BL/6, MD-2-/- and CD14-/- mice that will be utilized in assays similar to those described above to determine the activation and magnitude of TRIF and MyD88-dependent responses in the presence or absence of CD14.
|
