Abnormal distribution of aquaporin-5 water channel protein in salivary glands from Sjögren's syndrome patients

Serge Steinfeld, Elie Cogan, Landon S. King, Peter Agre, Robert Kiss, Christine Delporte

Research output: Contribution to journalArticlepeer-review

211 Scopus citations

Abstract

Patients with Sjögren's syndrome (SS) suffer from deficient secretion of saliva due to an autoimmune destruction of salivary glands, however, glandular dysfunction also occurs without destruction. Based upon its abnormal distribution in SS salivary glands, a potential role for the water channel protein aquaporin-5 (AQP5) is proposed in the pathogenesis of SS. The immunohistochemical distribution of AQP5 was compared in minor salivary gland biopsies obtained from women after informed consent: primary SS (53.2 ± 14 years old, n = 10), healthy volunteers (46.2 ± 17 years old, n = 10), patients with sarcoidosis (37 and 48 years old), and patients with non-specific sialoadenitis (54 and 61 years old). Biopsies from normal subjects revealed AQP5 primarily at the apical membrane of the salivary gland acinus. In contrast, biopsies from SS patients revealed AQP5 primarily at the basal membranes of the acinus. The AQP5 distribution in biopsies from patients with other dry mouth disorders, such as non-specific sialoadenitis or sarcoidosis, was similar to biopsies from control subjects. Computer-assisted microscopy was performed to quantitatively evaluate AQP5 distribution in the immunoreactive acini of both SS and control subjects. Biopsies from SS patients had higher labeling indices (percentage of acinus area immunoreactive for AQP5) at the basal membrane when compared with biopsies from control subjects. In contrast, biopsies of SS patients exhibited lower labeling indices at the apical membrane when compared with biopsies from control subjects. To verify the specificity of the AQP5 antibody, Western blot analysis was performed on membranes from Xenopus oocytes injected with AQP5 cRNA or on membranes from minor salivary glands of control subjects and SS patients. In each case, the immunoblots had a 27 kd band, corresponding to the expected molecular weight of AQP5. Abnormal distribution of AQP5 in salivary gland acini is likely to contribute to the deficiency of fluid secretion, which is a defining feature of Sjögren's syndrome.

Original languageEnglish (US)
Pages (from-to)143-148
Number of pages6
JournalLaboratory Investigation
Volume81
Issue number2
DOIs
StatePublished - 2001

ASJC Scopus subject areas

  • General Medicine

Fingerprint

Dive into the research topics of 'Abnormal distribution of aquaporin-5 water channel protein in salivary glands from Sjögren's syndrome patients'. Together they form a unique fingerprint.

Cite this