FIGURE SUMMARY
Title

Claudin-5 Affects Endothelial Autophagy in Response to Early Hypoxia

Authors
Yu, P., Li, Y., Zhong, G., Li, W., Chen, B., Zhang, J.
Source
Full text @ Front. Physiol.

The specificity of the involvement of Claudin-5 in autophagy under hypoxia induction. (A) Confocal microscopy images of Claudin-5 (green) and LC3 (purple). Colocalization of Claudin-5 with LC3 (white arrow) and quantitative analysis of LC3 levels by Image-Pro Plus. Mean±SD, n=3 independent experiments per group. Scale bar, 10μm. (B) Western blot analysis of the autophagy markers LC3 and LAMP-1. Mean±SD, n=3 independent experiments per group. *p<0.05 **p<0.01 and ***p<0.005.

Loss of Claudin-5b in zebrafish embryos inhibits activation of autophagy in cerebrovascular endothelial cells (ECs). Morpholino (MO) silencing of claudin-5b in endothelial eGFP-specific transgenic Tg(kdrl:eGFP) zebrafish embryos. (A) Brain phenotype (red arrowheads) of control MO and claudin-5b MO zebrafish larvae in response to hypoxia. Scale bar, 100μm. (B) Quantitative analysis of the severe injury rates of control MO and claudin-5b MO zebrafish larval brains. Mean±SD, n=3 independent experiments per group. (C) Confocal microscopy images of Claudin-5 (red) and LC3 (purple). Scale bar, 5μm. (D) Quantitative analysis of LC3 levels by Image-Pro Plus. Mean±SD, n=3 independent experiments per group. *p<0.05 and **p<0.01.

Caveolin-1 (Cav-1)-mediated Claudin-5 redistribution in response to hypoxia. (A) Confocal microscopy images of Claudin-5 (green) and Cav-1 (purple). Colocalization of Claudin-5 and Cav-1 (white arrows). Mean±SD, n=3 independent experiments per group. Scale bar, 10μm. (B) Western blot analysis of Cav-1 in the cytoplasm and membrane. Mean±SD, n=3 independent experiments per group. *p<0.05 and **p<0.01.

Inducible nitric oxide synthase (iNOS) induces Cav-1-mediated Claudin-5 translocation in response to hypoxia. (A,B) Confocal microscopy images of Claudin-5 (green), iNOS (purple), and hypoxia inducible factor 1 subunit alpha (HIF-1a; purple). Scale bar, 10μm. Mean±SD, n=3 independent experiments per group. (C) Western blot analysis of iNOS and HIF-1a. Mean±SD, n=3 independent experiments per group. *p<0.05 and **p<0.01.

FIGURE 5. Reactive oxygen species (ROS) production drives BCL2/adenovirus E1B 19kDa protein interacting protein 3 (Bnip3) expression in brain microvascular endothelial (bEnd.3) cells in response to hypoxia. (A) ROS analysis by flow cytometry and quantitative analysis of ROS intensity. (B) Western blot analysis of Bnip3. MeanĀ±SD, n=3 independent experiments per group. *p<0.05 and **p<0.01. (C) Schematic illustrating the mechanism that Claudin-5 is involved in autophagy in cerebral vascular endothelial cells in the early stage of hypoxia.

Acknowledgments
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