Impact of TLR3 activation on endothelial functions: insights into iNOS-dependent mechanisms
Year: 2026
Type: article
Abstract: Objective This study aimed to identify the role of inducible nitric oxide synthase (iNOS) in regulating endothelial cell (EC) function within the toll-like receptor 3 (TLR3) signaling pathway. Methods To activate TLR3 and inhibit iNOS, the TLR3 agonist poly(I:C) and the selective iNOS inhibitor 1400W were employed. Levels of iNOS, eNOS, and reactive oxygen species (ROS) were measured, and mitochondrial membrane potential (ΔΨm) was assessed to evaluate mitochondrial function. Cell proliferation, cell survival/growth, and cell death were evaluated using the BrdU assay, serial DAPI-based cell counting, and the apoptosis/death readout, respectively; caspase-3 activity was also measured. Results Activation of TLR3 increased iNOS levels while concurrently decreasing eNOS expression in an iNOS-independent manner. TLR3 activation also elevated intracellular ROS production and induced mitochondrial dysfunction and impaired cell survival through an iNOS-dependent mechanism. Early proliferative activity was transiently increased (24 h) in an iNOS-dependent manner, while ongoing cell death led to a net reduction in cell number. Conclusion iNOS is a major contributor to ROS production within the TLR3 pathway but exerts no notable influence on eNOS expression. These findings identify iNOS as a selective therapeutic target for TLR3-triggered vascular disorders, potentially obviating the need for eNOS inhibition.
Source: Molecular Biology Reports
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7204442723