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Activation of c-Src tyrosine kinase mediated the degradation of occludin in ventilator-induced lung injury.

Zhao T, Liu M, Gu C, Wang X, Wang Y - Respir. Res. (2014)

Bottom Line: HE staining and lung injury score showed more severe lung injury and alveolar edema in group H compared with group M and group C.For the in vitro study, occludin expression decreased and c-Src activation increased as indicated by the phosphorylation of c-Src over time.Mechanical ventilation can activate c-Src by phosphorylation and increase the degradation of occludin. c-Src inhibitor can ameliorate barrier function and lung injury by up-regulating occludin.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Qianfoshan Hospital, Shandong University, No. 16766 Jingshi Road, Jinan, 250014, Shandong Province, China. feishi_xin@126.com.

ABSTRACT

Background: Ventilator-induced lung injury (VILI) is characterized by increased alveolar permeability, pulmonary edema. The tyrosine kinase, c-Src, is involved in VILI but its role has not been fully elucidated. This study examined the relationship between c-Src activation and occludin levels in VILI both in vitro and in vivo.

Methods: For the in vivo study, Wistar rats were randomly divided into five groups: control (group C); normal tidal volume (group M); normal tidal volume + c-Src inhibitor (PP2) (group M + P); high tidal volume (group H); and high tidal volume + c-Src inhibitor (PP2) (group H + P). Rats in all groups but group C underwent mechanical ventilation for 4 h. For the in vitro study, MLE-12 cells pretreated with PP2 and siRNA underwent cyclic stretching at 8% or 20% for 0, 1, 2 and 4 h. The expressions of occludin, c-Src, and p-c-Src were analyzed by western blotting, hematoxylin and eosin (HE) staining, and immunofluorescence.

Results: For the in vivo study, rats in group H showed decreased occludin expression and activated c-Src compared with group C. HE staining and lung injury score showed more severe lung injury and alveolar edema in group H compared with group M and group C. Group H + P had less pulmonary edema induced by the high tidal volume ventilation. For the in vitro study, occludin expression decreased and c-Src activation increased as indicated by the phosphorylation of c-Src over time. Consistently, PP2 could restore occludin levels.

Conclusions: Mechanical ventilation can activate c-Src by phosphorylation and increase the degradation of occludin. c-Src inhibitor can ameliorate barrier function and lung injury by up-regulating occludin.

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Related in: MedlinePlus

Time course of cyclic stretch-induced degradation of occludin in MLE-12 cells. MLE-12 epithelial cells were exposed to 8% or 20% cyclic stretching for 0, 1, 2, and 4 h. Occludin expression was determined by Western blotting. The density of proteins in 0 h was used as a standard (1 arbitrary unit) to compare relative densities in the other times. **P < 0.05,*P < 0.05, compared with 0 h. Data are representative of 3 independent experiments.
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Fig1: Time course of cyclic stretch-induced degradation of occludin in MLE-12 cells. MLE-12 epithelial cells were exposed to 8% or 20% cyclic stretching for 0, 1, 2, and 4 h. Occludin expression was determined by Western blotting. The density of proteins in 0 h was used as a standard (1 arbitrary unit) to compare relative densities in the other times. **P < 0.05,*P < 0.05, compared with 0 h. Data are representative of 3 independent experiments.

Mentions: MLE-12 cells were treated with 8% or 20% cyclic stretching for 0, 1, 2 and 4 h. Occludin levels and total and phosphorylation of c-Src were detected by western blotting. Occludin expression was not significantly changed at 8% cyclic stretching (P > 0.05) (Figure 1). At 20% cyclic stretching, the expression of occludin was reduced in a time-dependent manner, reaching a final reduction of 70% at 4 h (P < 0.05) (Figure 1). After exposure of MLE-12 cells to 20% cyclic stretching for 0, 1, 2 and 4 h, c-Src was activated, and the level of total and phosphorylation c-Src increased (P < 0.05) (Figure 2).Figure 1


Activation of c-Src tyrosine kinase mediated the degradation of occludin in ventilator-induced lung injury.

Zhao T, Liu M, Gu C, Wang X, Wang Y - Respir. Res. (2014)

Time course of cyclic stretch-induced degradation of occludin in MLE-12 cells. MLE-12 epithelial cells were exposed to 8% or 20% cyclic stretching for 0, 1, 2, and 4 h. Occludin expression was determined by Western blotting. The density of proteins in 0 h was used as a standard (1 arbitrary unit) to compare relative densities in the other times. **P < 0.05,*P < 0.05, compared with 0 h. Data are representative of 3 independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4262993&req=5

Fig1: Time course of cyclic stretch-induced degradation of occludin in MLE-12 cells. MLE-12 epithelial cells were exposed to 8% or 20% cyclic stretching for 0, 1, 2, and 4 h. Occludin expression was determined by Western blotting. The density of proteins in 0 h was used as a standard (1 arbitrary unit) to compare relative densities in the other times. **P < 0.05,*P < 0.05, compared with 0 h. Data are representative of 3 independent experiments.
Mentions: MLE-12 cells were treated with 8% or 20% cyclic stretching for 0, 1, 2 and 4 h. Occludin levels and total and phosphorylation of c-Src were detected by western blotting. Occludin expression was not significantly changed at 8% cyclic stretching (P > 0.05) (Figure 1). At 20% cyclic stretching, the expression of occludin was reduced in a time-dependent manner, reaching a final reduction of 70% at 4 h (P < 0.05) (Figure 1). After exposure of MLE-12 cells to 20% cyclic stretching for 0, 1, 2 and 4 h, c-Src was activated, and the level of total and phosphorylation c-Src increased (P < 0.05) (Figure 2).Figure 1

Bottom Line: HE staining and lung injury score showed more severe lung injury and alveolar edema in group H compared with group M and group C.For the in vitro study, occludin expression decreased and c-Src activation increased as indicated by the phosphorylation of c-Src over time.Mechanical ventilation can activate c-Src by phosphorylation and increase the degradation of occludin. c-Src inhibitor can ameliorate barrier function and lung injury by up-regulating occludin.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Qianfoshan Hospital, Shandong University, No. 16766 Jingshi Road, Jinan, 250014, Shandong Province, China. feishi_xin@126.com.

ABSTRACT

Background: Ventilator-induced lung injury (VILI) is characterized by increased alveolar permeability, pulmonary edema. The tyrosine kinase, c-Src, is involved in VILI but its role has not been fully elucidated. This study examined the relationship between c-Src activation and occludin levels in VILI both in vitro and in vivo.

Methods: For the in vivo study, Wistar rats were randomly divided into five groups: control (group C); normal tidal volume (group M); normal tidal volume + c-Src inhibitor (PP2) (group M + P); high tidal volume (group H); and high tidal volume + c-Src inhibitor (PP2) (group H + P). Rats in all groups but group C underwent mechanical ventilation for 4 h. For the in vitro study, MLE-12 cells pretreated with PP2 and siRNA underwent cyclic stretching at 8% or 20% for 0, 1, 2 and 4 h. The expressions of occludin, c-Src, and p-c-Src were analyzed by western blotting, hematoxylin and eosin (HE) staining, and immunofluorescence.

Results: For the in vivo study, rats in group H showed decreased occludin expression and activated c-Src compared with group C. HE staining and lung injury score showed more severe lung injury and alveolar edema in group H compared with group M and group C. Group H + P had less pulmonary edema induced by the high tidal volume ventilation. For the in vitro study, occludin expression decreased and c-Src activation increased as indicated by the phosphorylation of c-Src over time. Consistently, PP2 could restore occludin levels.

Conclusions: Mechanical ventilation can activate c-Src by phosphorylation and increase the degradation of occludin. c-Src inhibitor can ameliorate barrier function and lung injury by up-regulating occludin.

Show MeSH
Related in: MedlinePlus