UTP regulation of ion transport in alveolar epithelial cells involves distinct mechanisms

Chuanxiu Yang, Lijing Su, Yang Wang, Lin Liu

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

UTP is known to regulate alveolar fluid clearance. However, the relative contribution of alveolar type I cells and type II cells to this process is unknown. In this study, we investigated the effects of UTP on ion transport in type I-like cell (AEC I) and type II-like cell (AEC II) monolayers. Luminal treatment of cell monolayers with UTP increased short-circuit current (I sc) of AEC II but decreased Isc of AEC I. The Cl - channel blockers NPPB and DIDS inhibited the UTP-induced changes in Isc (ΔIsc) in both types of cells. Amiloride, an inhibitor of epithelial Na+ channels (ENaC), abolished the UTP-induced ΔIsc in AEC I, but not in AEC II. The general blocker of K + channels, BaCl2, eliminated the UTP-induced ΔIsc in AEC II, but not in AEC I. The intermediate conductance (IKCa) blocker, clofilium, also blocked the UTP effect in AEC II. The signal transduction pathways mediated by UTP were the same in AEC I and AEC II. Furthermore, UTP increased Cl- secretion in AEC II and Cl - absorption in AEC I. Our results suggest that UTP induces opposite changes in Isc in AEC I and AEC II, likely due to the reversed Cl- flux and different contributions of ENaC and IKCa. Our results further imply a new concept that type II cells contribute to UTP-induced fluid secretion and type I cells contribute to UTP-induced fluid absorption in alveoli.

Original languageEnglish (US)
Pages (from-to)L439-L454
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume297
Issue number3
DOIs
StatePublished - Sep 2009

Keywords

  • Fluid transport
  • Short-circuit current

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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