shRNA-expressing plasmids were formulated with in vivo-jetPEI. Rats were intravenously injected with at a dose of 1 mg/kg body weight via tail vein.

Toll-like receptor 2 (TLR2) and TLR4 belong to a family of highly conserved pattern recognition receptors and are well-known upstream sensors of signaling pathways of innate immunity. TLR2 and TLR4 upregulation is thought to be associated with poor outcome in stroke patients. We currently show that transient focal ischemia in adult rats induces TLR2 and TLR4 expression within hours and shRNA-mediated knockdown of TLR2 and TLR4 alone and in combination decreases the infarct size and swelling. We further show that TLR2 and TLR4 knockdown also prevented the induction of their downstream signaling molecules MyD88, IRAK1, and NFkappaB p65 as well as the pro-inflammatory cytokines IL-1beta, IL-6, and TNFalpha. This study thus shows that attenuation of the severity of TLR2- and TLR4-mediated post-stroke inflammation ameliorates ischemic brain damage.