Expression of cftr in human and bovine thyroid epithelium.
Devuyst, Olivier, Philippe E. Golstein, Marcio V. Sanches, Klaus
Piontek, Patricia D. Wilson, William B. Guggino, Jacques E. Dumont,
and Renaud Beauwens.
Division of Nephrology and Department of Physiology, Johns Hopkins
Medical School, Baltimore, MD 21205; Department of Pathophysiology
and Institute of Interdisciplinary Research, Free University of
Brussels Medical School, B-1070 Brussels, Belgium
APStracts 3:0386C, 1996.
The expression of CFTR in the thyroid has not been documented to date,
although a role for CFTR in the thyroid follicular epithelium is
suggested both clinically, by the occurence of subclinical
hypothyroidism in patients with cystic fibrosis (CF), and
physiologically, by the presence of low-conductance, cAMP-activated
chloride channels in the follicular cells. Using RT-PCR with nested
primers derived from exons 13 and 14 of the human CF gene, we have
now documented the presence of CFTR mRNA in the human thyroid. Using
six antibodies directed against different domains of human CFTR,
Western blot analyses showed that a 165 kDa band was present in
membrane extracts from bovine and human thyroid. This protein has the
predicted size of mature CFTR and was not detected with pre-immune
serum or pre-adsorbed antiserum. By immunofluorescence and
immunoperoxidase, CFTR was located in the follicular cells, with a
diffuse, intracellular labeling pattern. Quantitative analysis
revealed that 64% of the follicles were CFTR-positive, while 16% of
the follicular cells only were stained per follicle. The number of
CFTR-positive cells was inversely proportional to the size of the
follicle. These results (i) demonstrate the expression of CFTR at the
mRNA and protein levels in human and bovine thyroid follicular cells;
(ii) suggest that CFTR expression could be instrumental in follicular
enlargement.
Received 27 March 1996; accepted in final form 18 September 1996.
APS Manuscript Number C174-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996