Toll-like receptor 4 signaling in dysfunction of cardiac microvascular endothelial cells under hypoxia/reoxygenation
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This study was designed to detect the role of Toll-like receptor 4 (TLR4) signaling in the dysfunction of cardiac microvascular endothelial cells (CMECs) after hypoxia/reoxygenation (H/R).
The cell viability of CMECs was measured by MTT assay. The migration of CMECs was detected by cell scratch wound assay. The expressions of TLR4, nuclear factor-kappa B (NF-κB) and eNOS were analyzed by Western blot. Secretions of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were determined by NO detection kit and ELISA.
Lipopolysaccharide (LPS) incubation increased the expressions of TLR4, NF-κB, IL-6 and TNF-α in CMECs (P < 0.05 vs. control). The CMECs after H/R injury had impaired cell viability (P < 0.01 vs. control) and migration ability (P < 0.05 vs. control). Moreover, the expressions of TLR4, NF-κB, IL-6 and TNF-α were elevated after H/R in CMECs (P < 0.01 vs. control), while NO and the eNOS expression were significantly decreased. In contrast, administration of the TLR4-neutralizing antibody MTS510 prior to H/R injury down-regulated the expressions of IL-6 and TNF-α and attenuated the dysfunction of CMECs.
TLR4 and its signaling components can be activated by LPS and H/R in CMECs. Blocking the TLR4 signal pathway before H/R injury attenuates CMEC dysfunction.
KeywordsToll-like receptor 4 Cardiac microvascular endothelial cells Lipopolysaccharide Hypoxia/reoxygenation Apoptosis
This study was supported by grants from the National Natural Science Foundation of China (NSFC, No. 30970845, 30770784) and Xijing Research Boosting Program (No. XJZT08Z04 XJZT07Z05).
Conflict of interest
- 22.Wei L, Yin Z, Yuan Y, Hwang A, Lee A, Sun D, et al. A PKC-beta inhibitor treatment reverses cardiac microvascular barrier dysfunction in diabetic rats. Microvasc Res. 2010;80:158–65.Google Scholar