Na -K -ATPase α1 Identified as an Abundant Protein in the Blood-Labyrinth Barrier That Plays an Essential Role in the Barrier IntegrityReportar como inadecuado

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The endothelial-blood-tissue barrier is critical for maintaining tissue homeostasis. The ear harbors a unique endothelial-blood-tissue barrier which we term -blood-labyrinth-barrier-. This barrier is critical for maintaining inner ear homeostasis. Disruption of the blood-labyrinth-barrier is closely associated with a number of hearing disorders. Many proteins of the blood-brain-barrier and blood-retinal-barrier have been identified, leading to significant advances in understanding their tissue specific functions. In contrast, capillaries in the ear are small in volume and anatomically complex. This presents a challenge for protein analysis studies, which has resulted in limited knowledge of the molecular and functional components of the blood-labyrinth-barrier. In this study, we developed a novel method for isolation of the stria vascularis capillary from CBA-CaJ mouse cochlea and provided the first database of protein components in the blood-labyrinth barrier as well as evidence that the interaction of Na+-K+-ATPase α1 ATP1A1 with protein kinase C eta PKCη and occludin is one of the mechanisms of loud sound-induced vascular permeability increase.

Methodology-Principal Findings

Using a mass-spectrometry, shotgun-proteomics approach combined with a novel -sandwich-dissociation- method, more than 600 proteins from isolated stria vascularis capillaries were identified from adult CBA-CaJ mouse cochlea. The ion transporter ATP1A1 was the most abundant protein in the blood-labyrinth barrier. Pharmacological inhibition of ATP1A1 activity resulted in hyperphosphorylation of tight junction proteins such as occludin which increased the blood-labyrinth-barrier permeability. PKCη directly interacted with ATP1A1 and was an essential mediator of ATP1A1-initiated occludin phosphorylation. Moreover, this identified signaling pathway was involved in the breakdown of the blood-labyrinth-barrier resulting from loud sound trauma.


The results presented here provide a novel method for capillary isolation from the inner ear and the first database on protein components in the blood-labyrinth-barrier. Additionally, we found that ATP1A1 interaction with PKCη and occludin was involved in the integrity of the blood-labyrinth-barrier.

Autor: Yue Yang, Min Dai, Teresa M. Wilson, Irina Omelchenko, John E. Klimek, Phillip A. Wilmarth, Larry L. David, Alfred L. Nuttall, Pe



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