Protein tyrosine kinase 6 mediates TNFα-induced endothelial barrier dysfunction

Abstract

A key event in the progression of systemic inflammation resulting from severe trauma or shock involves microvascular hyperpermeability, which leads to excessive plasma fluid and proteins accumulating in extravascular space resulting in tissue edema. The precise molecular mechanism of the hyperpermeability response is not completely understood. Protein tyrosine kinase 6 (PTK6, also known as breast tumor kinase BRK) is a non-receptor tyrosine kinase related to Src-family proteins. Although it has also been shown that PTK6 participates in regulating epithelial barrier function, the role of PTK6 in endothelial barrier function has not been reported. In this study, we hypothesized that PTK6 is 1) expressed in vascular endothelial cells, and 2) contributes to vascular endothelial hyperpermeability in response to TNFα. Results showed that PTK6 was detected in mouse endothelial cells at the level of protein and mRNA. In addition, PTK6 knockdown attenuated TNFα induced decrease in endothelial barrier function as measured by electric cell-substrate impedance sensing (ECIS) and in vitro transwell albumin-flux assays. Furthermore, we showed that TNFα treatment of endothelial cells increased active PTK6 association with p120-catenin at endothelial cell-cell junctions. Further analysis using immunocytochemistry and immunoprecipitation demonstrated that PTK6 knockdown attenuated TNFα induced VE-cadherin internalization as well as promoting its association with p120-catenin. Our study demonstrates a novel role of PTK6 in mediating endothelial barrier dysfunction.

Pro-inflammatory TNFα and IL-1β differentially regulate the inflammatory phenotype of brain microvascular endothelial cells

“…This response was small, reflecting approximately 10–15 % difference in norm resistance. Reduced TEER over this period has been reported by others [ 32 , 33 ]. After this acute period, the barrier resistance of the HCMVECs increased in a cytokine, concentration and time-dependant manner.…”

“…After this acute period, the barrier resistance of the HCMVECs increased in a cytokine, concentration and time-dependant manner. This strengthening of the barrier occurs over a period, which is (surprisingly) omitted in other ECIS studies [ 32 , 33 ]. The magnitude of the increase in barrier resistance is greater and occurs for longer for TNFα.…”

Glaucocalyxin A inhibits hydrogen peroxide‐induced oxidative stress and inflammatory response in coronary artery smooth muscle cells

“…19 TNF-α, one of the major pro-inflammatory cytokines, promotes inflammatory cell infiltration, induces vascular endothelial cell injury, and enhances the generation of ROS. 20 Here, we found that GLA treatment reduced the production of several pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6 in In the present study, we showed that GLA treatment suppressed p38 phosphorylation and NF-κB activation in H 2 O 2 -induced HCASMCs.…”

Phosphorylation and isoform use in p120-catenin during development and tumorigenesis

“…With regards to nonreceptor tyrosine kinases, as noted earlier, Fer-kinase associates to an amino-terminal region of p120 (amino acids 131–156), between p120’s 3 rd and 4 th translational start sites (Figure 1) (Kim and Wong, 1995), with Src and Fyn sites mapped relatively nearby to Y112, Y217 and Y228. Recently, the non-receptor tyrosine kinase PTK6 (Protein receptor tyrosine kinase 6) was found in association with p120-catenin, although its phosphorylation of p120-catenin has yet to be characterized (Haines et al, 2015). …”