Over-expression of a RhoA-specific guanine nucleotide exchange factor, p190RhoGEF, in mouse dendritic cells negatively regulates cellular responses to bacterial lipopolysaccharide.

We studied the role of a RhoA-specific guanine nucleotide exchange factor (p190RhoGEF) in dendritic cells (DCs), using transgenic (TG) mice that over-express a full gene of p190RhoGEF under the control of an invariant chain promoter. TG mice lacked localization of activated DCs to the T cell zone in the spleen and had reduced serum levels of IL-6 in response to lipopolysaccharide (LPS) injection. DCs from these mice also showed reduced surface expression of CD86, CD40, and CD205, but not MHCII, as well as a reduced capability to uptake antigen. Moreover, chemokine-driven migration and secretion of IL-6, but not of IL-12, were impaired after LPS-stimulation of TG DCs. Collectively, these results suggest that over-expressing p190RhoGEF negatively regulates conventional DC function in response to bacterial LPS infection.