The aquaporin 1 C-terminal tail is required for migration and growth of pulmonary arterial myocytes

Ning Lai, Julie Lade, Kyle Leggett, Xin Yun, Syeda Baksh, Eric Chau, Michael T. Crow, Venkataramana Sidhaye, Jian Wang, Larissa A. Shimoda

Research output: Contribution to journalArticlepeer-review

Abstract

Pulmonary arterial smoothmuscle cell (PASMC) proliferation and migration are important contributors to the vascular remodeling that occurs during development of pulmonary hypertension. We previously demonstrated that aquaporin (AQP)1, amember of the water channel family of proteins, was expressed in PASMCs and was necessary for hypoxia-induced migration; however, the mechanism by which AQP1 controls this response is unclear. The C-terminal tail of AQP1 contains putative calcium (EF-hand) and protein binding sites. Thus, we wanted to explore whether the C-terminal tail or the EF-hand motif of AQP1 was required for migration and proliferation. Rat PASMCs were isolated from distal pulmonary arteries, and proliferation and migration were measured using BrdU incorporation and transwell filters, respectively. To deplete AQP1, PASMCs were transfected with AQP1 small interference RNA (siRNA) or nontargeting siRNA. Knockdown of AQP1 reduced basal proliferation and hypoxia-induced migration and proliferation in PASMCs. In subsequent experiments, wild-type AQP1, AQP1 lacking the entire cytoplasmic C-terminal tail, or AQP1 with amutation in the EF-hand motif were expressed in PASMCs using adenoviral constructs. For all AQP1 constructs, infection increased AQP1 protein levels, water permeability, and the change in cell volume induced by hypotonic challenge. Infection with wild-type and EF-hand mutated AQP1, but not C-terminal-deleted AQP1, increased PASMCmigration and proliferation. Our results suggest that AQP1 controls proliferation and migration in PASMCs and that the mechanism requires the C-terminal tail of the protein but is independent of water transport or the EF-hand motif.

Original languageEnglish (US)
Pages (from-to)1010-1020
Number of pages11
JournalAmerican journal of respiratory cell and molecular biology
Volume50
Issue number6
DOIs
StatePublished - Jun 2014

Keywords

  • EF-hand motif
  • Hypoxia
  • Proliferation
  • Smooth muscle cells

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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