A functional polymorphism in the promoter region of TLR3 is associated with susceptibility to end-stage renal disease

Toll-like Receptors as Potential Therapeutic Targets in Kidney Diseases

Toll-like Receptors (TLRs) are members of pattern recognition receptors and serve a pivotal role in host immunity. TLRs response to pathogen-associated molecular patterns encoded by pathogens or damage-associated molecular patterns released by dying cells, initiating an inflammatory cascade, where both beneficial and detrimental effects can be exerted. Accumulated evidence has revealed that TLRs are closely associated with various kidney diseases but their roles are still not well understood. This review updated evidence on the roles of TLRs in the pathogenesis of kidney diseases including urinary tract infection, glomerulonephritis, acute kidney injury, transplant allograft dysfunction and chronic kidney diseases.

Activation of Toll-like receptor 3 increases mouse aortic vascular smooth muscle cell contractility through ERK1/2 pathway

Activation of Toll-like receptor 3 (TLR3), a pattern recognition receptor of the innate immune system, is associated with vascular complications. However, whether activation of TLR3 alters vascular contractility is unknown. We, therefore, hypothesized that TLR3 activation augments vascular contractility and activates vascular smooth muscle cell (VSMC) contractile apparatus proteins. Male mice were treated with polyinosinic-polycytidylic acid (Poly I:C group, 14 days), a TLR3 agonist; control mice received saline (vehicle, 14 days). At the end of protocol, blood pressure was measured by tail cuff method. Aortas were isolated and assessed for contractility experiments using a wire myograph. Aortic protein content was used to determine phosphorylated/total interferon regulatory factor 3 (IRF3), a downstream target of TLR3 signaling, and ERK1/2 using Western blot. We investigated the TLR3/IRF3/ERK1/2 signaling pathway and contractile-related proteins such as phosphorylated/total myosin light chain (MLC) and caldesmon (CaD) in aortic VSMC primary cultures. Poly I:C-treated mice exhibited (vs. vehicle-treated mice) (1) elevated systolic blood pressure. Moreover, Poly I:C treatment (2) enhanced aortic phenylephrine-induced maximum contraction, which was suppressed by PD98059 (ERK1/2 inhibitor), and (3) increased aortic levels of phosphorylated IRF3 and ERK1/2. Stimulation of mouse aortic VSMCs with Poly I:C resulted in increased phosphorylation of IRF3, ERK1/2, MLC, and CaD. Inhibition of ERK1/2 abolished Poly I:C-mediated phosphorylation of MLC and CaD. Our data provide functional evidence for the role of TLR3 in vascular contractile events, suggesting TLR3 as a potential new therapeutic target in vascular dysfunction and regulation of blood pressure.