Open AccessAnalysis of C5a-mediated chemotaxis by lentiviral delivery of small interfering RNA
Author(s) -
Jong Ik Hwang,
Iain D. C. Fraser,
Sangdun Choi,
F. Xiao-Feng Qin,
Melvin I. Simon
Publication year - 2003
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0307549100
Subject(s) - phosphorylation , chemotaxis , small interfering rna , microbiology and biotechnology , biology , rna interference , beta (programming language) , gene knockdown , rna , cell culture , transfection , receptor , biochemistry , gene , genetics , computer science , programming language
Immune cells respond to chemotactic signals by means of G protein-coupled receptors. Attempts to elucidate the function of specific G protein family members in these responses is complicated by redundancy among the different G protein isoforms. We have used lentiviral-based RNA interference to eliminate expression of specific G protein subunits selectively in J774A.1 mouse macrophages. The chemotactic response to the complement factors C5a and C3a is ablated in cells lacking G beta(2) but is unaffected in cells lacking G beta(1), G alpha i(2), or G alpha i(3). Similarly, the C5a-mediated calcium response of single cells is either absent or significantly delayed and weakened by G beta(2) knockdown. Assessment of Akt1 phosphorylation levels in response to C5a shows rapid and sustained phosphorylation in both wild-type cells and cells lacking G beta(1). Cells lacking G beta(2) retain the rapid response but cannot sustain phospho-Akt1 levels. The phenotype of cells lacking G beta(2) can be reversed by overexpression of either human G beta(2) or mouse G beta(1). These data demonstrate the usefulness of lentiviral-based RNA interference in the systematic analysis of a signaling pathway, and they suggest that in J774A.1 cells, G beta(2)-derived G beta gamma is the most effective mediator of chemotaxis to C5a.