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Title: Regulation of intestinal epithelial cell growth by transforming growth factor type. beta

A nontransformed rat jejunal crypt cell line (IEC-6) expresses transforming growth factor type {beta}1 (TGF-{beta}1) mRNA, secretes latent {sup 125}I-labeled TGF-{beta}1 to specific, high-affinity cell surface receptors. IEC-6 cell growth is markedly inhibited by TGF-{beta}1 and TGF-{beta}2 with half-maximal inhibition occurring between 0.1 and 1.0 ng of TGF-{beta}1 per ml. TGF-{beta}1-mediated growth inhibition is not associated with the appearance of biochemical markers of enterocyte differentiation such as alkaline phosphatase expression and sucrase activity. TGF-{beta}1 increases steady-state levels of its own mRNA expression within 8 hr of treatment of rapidly growing IEC-6 cells. In freshly isolated rat jejunal enterocytes that are sequentially eluted from the crypt villus axis, TGF-{beta}1 mRNA expression is most abundant in terminally differentiated villus tip cells and least abundant in the less differentiated, mitotically active crypt cells. The authors conclude that TGF-{beta}1 is an autoregulated growth inhibitor in IEC-6 cells that potentially functions in an autocrine manner. In the rat jejunal epithelium, TGF-{beta}1 expression is most prominently localized to the villus tip--i.e., the region of the crypt villus unit that is characterized by the terminally differentiated phenotype. These data suggest that TGF-{beta}1 may function in coordination of the rapid cell turnover typical for the intestinal epithelium.
Authors:
; ; ;  [1]
  1. (Vanderbilt Univ. School of Medicine, Nashville, TN (USA))
Publication Date:
OSTI Identifier:
5037062
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA); Journal Volume: 86:5
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; EPITHELIUM; CELL DIFFERENTIATION; GROWTH FACTORS; RADIORECEPTOR ASSAY; AUTORADIOGRAPHY; CELL PROLIFERATION; CRYPT CELLS; GROWTH; IODINE 125; MESSENGER-RNA; PHOSPHORUS 32; RATS; THYMIDINE; TRITIUM COMPOUNDS; ANIMAL CELLS; ANIMAL TISSUES; ANIMALS; AZINES; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BODY; DAYS LIVING RADIOISOTOPES; ELECTRON CAPTURE RADIOISOTOPES; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; LIGHT NUCLEI; MAMMALS; MITOGENS; NUCLEI; NUCLEIC ACIDS; NUCLEOSIDES; NUCLEOTIDES; ODD-EVEN NUCLEI; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHOSPHORUS ISOTOPES; PROTEINS; PYRIMIDINES; RADIOISOTOPES; RIBOSIDES; RNA; RODENTS; SOMATIC CELLS; TISSUES; TRACER TECHNIQUES; VERTEBRATES 550201* -- Biochemistry-- Tracer Techniques