Role of proneuregulin 1 cleavage and human epidermal growth factor receptor activation in hypertonic aquaporin induction

doi:10.1073/pnas.0406853101

Role of proneuregulin 1 cleavage and human epidermal growth factor receptor activation in hypertonic aquaporin induction

^*Renal Unit, Massachusetts General Hospital, Boston, MA 02114; ^†Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142; and ^‡Division of Pulmonary and Critical Care Medicine, and Departments of ^§Medicine and ^¶Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21224

Communicated by Peter C. Agre, The Johns Hopkins University School of Medicine, Baltimore, MD, September 15, 2004 (received for review July 11, 2004)

Abstract

Mammalian cells are confronted with changes in extracellular osmolality at various sites, including the aqueous layer above the lung epithelium. Hypertonic shock induces the activation of mitogen-activated protein kinases and the expression of a defined set of genes, including aquaporins. We investigated upstream components of the response to hypertonicity in lung epithelial cells and found that before extracellular signal-regulated kinase activation and aquaporin synthesis, the membrane-bound prohormone neuregulin 1-β is cleaved and binds to human epidermal growth factor receptor 3 (HER3). The signaling is prevented by matrix metalloproteinase inhibition, inhibition of neuregulin 1-β binding to HER3, and inhibition of HER tyrosine kinase activity. Inhibition of HER activation interferes with the hypertonic induction of two different aquaporins in three distinct cell lines of mouse and human origin. We propose that ligand-dependent HER activation constitutes a generalized signaling principle in the mammalian hypertonic stress response relevant to aquaporin expression.

Footnotes

↵ ∥ To whom correspondence should be addressed at: The Johns Hopkins Asthma and Allergy Center 4B.64, 5501 Hopkins Bayview Circle, Baltimore, MD 21224. E-mail: lsking{at}jhmi.edu.
Author contributions: A.H., V.L., and L.S.K. designed research; A.H., V.L., and L.S.K. performed research; A.H., V.L., and L.S.K. analyzed data; and A.H. and L.S.K. wrote the paper.
Abbreviations: AQP, aquaporin; DTSSP, 3,3′-dithiobis(sulfosuccinimidyl propionate); HER, human epidermal growth factor receptor; ERK, extracellular signal-regulated kinase; P-ERK, phosphorylated ERK; MAPK, mitogen-activated protein kinase; MLE, mouse lung epithelial cell line; MMP, matrix metalloproteinase; mOsm, milliosmolal; NRG1, neuregulin 1; PDGF, platelet-derived growth factor; PI3-kinase, phosphatidylinositol 3-kinase; RTK, receptor tyrosine kinase; PA, phorbol 12-tetradecanoate 13-acetate.