Guanylin and functional coupling proteins in the human salivary glands and gland tumors : expression, cellular localization, and target membrane domains.

Abstract

Cystic fibrosis transmembrane conductance regulator (CFTR)-mediated secretion of an electrolyte-rich fluid is a major but incompletely understood function of the salivary glands. We provide molecular evidence that guanylin, a bioactive intestinal peptide involved in the CFTR-regulated secretion of electrolyte/water in the gut epithelium, is highly expressed in the human parotid and submandibular glands and in respective clinically most relevant tumors. Moreover, in the same organs we identified expression of the major components of the guanylin signaling pathway, ie, guanylin-receptor guanylate cyclase-C, cGKII, and CFTR, as well as of the epithelial Cl(-)/HCO(3)(-) anion exchanger type 2 (AE2). At the cellular level, guanylin is localized to epithelial cells of the ductal system that, based on its presence in the saliva, is obviously released into the salivary gland ducts. The guanylin-receptor guanylate cyclase-C, cGKII, CFTR, and AE2 are all confined exclusively to the apical membrane of the same duct cells. These findings implicate guanylin as intrinsic regulator of electrolyte secretion in the salivary glands. We assume that duct epithelial cells synthesize and release guanylin into the saliva to regulate electrolyte secretion in the ductal system by an intraductal luminocrine signaling pathway. Moreover, the high expression of guanylin in pleomorphic adenoma and Warthin tumors (cystadenolymphoma), the most common neoplasms of salivary glands, predicts guanylin as a significant marker in tumor pathology.

• Authors: Hasan Kulaksiz, Elisabeth Rehberg, Wolfgang Stremmel, Yalcin Cetin
• Journal: The American journal of pathology (Am J Pathol) Vol. 161 Issue 2 Pg. 655-64 (Aug 2002) ISSN: 0002-9440 [Print] United States
• PMID: 12163390 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• CFTR protein, human
• Gastrointestinal Hormones
• Natriuretic Peptides
• Peptides
• Cystic Fibrosis Transmembrane Conductance Regulator
• guanylin

Topics

• Adenolymphoma (metabolism)
• Adenoma (metabolism)
• Biomarkers, Tumor
• Cystic Fibrosis Transmembrane Conductance Regulator (genetics, metabolism)
• Gastrointestinal Hormones
• Humans
• Natriuretic Peptides
• Parotid Gland (metabolism, pathology)
• Peptides (metabolism)
• Protein Structure, Tertiary
• Salivary Gland Neoplasms (metabolism)
• Salivary Glands (metabolism, pathology)
• Signal Transduction