HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 296/3/L555    most recent 90456.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Aschner, J. L. Articles by Fike, C. D. Search for Related Content PubMed PubMed Citation Articles by Aschner, J. L. Articles by Fike, C. D.

Heat shock protein 90-eNOS interactions mature with postnatal age in the pulmonary circulation of the piglet

¹Department of Pediatrics, ²The Vanderbilt Kennedy Center, ³The Vanderbilt Center for Molecular Toxicology, and ⁴Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee

Submitted 22 August 2008 ; accepted in final form 4 January 2009

Binding of endothelial nitric oxide synthase (eNOS) to the chaperone protein, Hsp90, promotes coupled eNOS synthetic activity. Using resistance level pulmonary arteries (PRA) from 2-day-, 5- to 7-day-, and 12-day-old piglets, we tested the hypothesis that Hsp90-eNOS interactions are developmentally regulated in the early neonatal period. PRA were isolated for coimmunoprecipitation and immunoblot analyses or cannulated for continuous diameter measurements using the pressurized myography technique. NOS inhibition caused less constriction in PRA from 2-day- compared with 5- to 7-day- and 12-day-old piglets. No age-related differences were found in dilation responses to an NO donor or in protein expression of Hsp90, phospho-eNOS (Ser¹¹⁷⁷), Akt, phospho-Akt, or caveolin-1. Compared with the older animals, PRA from 2-day-old piglets had higher total eNOS expression but displayed less binding of eNOS to Hsp90 and Akt. Hsp90 antagonism with radicicol induced greatest constriction in PRA from 12-day-old piglets. ACh stimulation caused dilation in PRA from 5- to 7-day- and 12-day-old but not 2-day-old animals, despite rapid and equivalent ACh-mediated eNOS phosphorylation (Ser¹¹⁷⁷) in all three age groups. Hsp90 inhibition abolished ACh-mediated dilation in PRA from the older piglets. ACh failed to stimulate Hsp90-eNOS binding in 2-day-old but induced a significant increase in Hsp90-eNOS coimmunoprecipitation in PRA from the older age groups, which was blocked by Hsp90 antagonism. We conclude that physical interactions between Hsp90 and eNOS mature over the first weeks of life, likely contributing to the postnatal fall in pulmonary vascular resistance and changes in agonist-induced pulmonary vascular responses characteristic of the early neonatal period.

Akt; development; nitric oxide