Presenting Author: Mehnaz M Falguni
, Graduate Research Assistant at Towson Univ.
Abstract:
Almost two million American adults are diagnosed with sepsis annually, and 350,000 succumb to the infection. The innate immune Toll-like-receptor 4 (TLR4) recognizes Gram-negative lipopolysaccharide (LPS) initiating inflammation. Additionally, acellular complement proteins amplify inflammation during infection. A murine model of endotoxemia is used to investigate complement activation using RT-qPCR and Western blots with organs collected 0-, 6-, 12-, and 18-hours post-injection with 30 mg/kg Escherichia coli LPS in WT and TLR4-/- mice. Transcription levels of complement genes C1qb, Masp1, F5, and Mbl1 are maintained at 6 hours in TLR4-/- mice liver while WT levels decrease. WT and TLR4-/- mouse serum samples were incubated with 1.0 µg/mL and 10.0 µg/mL of E. coli LPS, then levels of C3 cleavage are measured by Western blot. Significant dose-dependent C3 cleavage is observed in both groups. Next, the impact of LPS O-antigen on C3 cleavage efficiency was examined by incubating whole LPS or the lipid A portion with WT serum. Yersinia pestis LPS, with structurally distinct lipid A, initiates C3 cleavage with similar efficiency, indicating that acyl-chain arrangement minimally contributes to the ability of LPS to activate complement. Results suggest that complement may compensate for lack of canonical pathways in immunosuppressed patients. Further understanding of LPS and serum complement interactions may aid in developing therapies to control the downstream effects of infection.
Characterizing LPS-Induced Complement Activation Over the Course of Murine Endotoxemia
Category
Poster and Podium (Block Symposium)
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Date: May 5 Presentation Time: 03:15 PM to 04:30 PM Room: Exhibit Hall F1