EXPRESSION OF TRANSFORMING GROWTH-FACTOR-BETA (TGF-BETA) ISOFORMS ANDTGF-BETA TYPE-II RECEPTOR MESSENGER-RIBONUCLEIC-ACID AND PROTEIN, ANDTHE EFFECT OF TGF-BETA-S ON ENDOMETRIAL STROMAL CELL-GROWTH AND PROTEIN-DEGRADATION IN-VITRO
Xm. Tang et al., EXPRESSION OF TRANSFORMING GROWTH-FACTOR-BETA (TGF-BETA) ISOFORMS ANDTGF-BETA TYPE-II RECEPTOR MESSENGER-RIBONUCLEIC-ACID AND PROTEIN, ANDTHE EFFECT OF TGF-BETA-S ON ENDOMETRIAL STROMAL CELL-GROWTH AND PROTEIN-DEGRADATION IN-VITRO, Endocrinology, 135(1), 1994, pp. 450-459
Reverse transcription-polymerase chain reaction analysis of total RNA
and immunocytochemical observations revealed that human endometrial gl
andular epithelial and stromal cells in primary culture express messen
ger RNAs and proteins for transforming growth factor-beta 1 (TGF beta
1), TGF beta 2, and TGF beta 3 as well as TGF beta type II receptor. T
he epithelial and stromal cells synthesize and secrete into their cult
ure-conditioned medium 2.6 +/- 0.3 and 1.4 +/- 0.2 ng TGF beta 1/10(6)
cells, respectively; after transient acidification of the medium, the
TGF beta 1 levels were 18.1 +/- 0.4 and 7.8 +/- 0.7 ng/10(6) cells. T
hese cells also contain specific binding sites for [I-125]TGF beta 1,
indicated by light microscope autoradiography. TGF beta s at 0.01-10 n
g/ml neither stimulated or inhibited subconfluent quiescent stromal ce
lls under serum-free condition nor altered the mitogenic action of 10%
fetal bovine serum. However, in the presence of 2% fetal bovine serum
, which induced half-maximal stimulation of [H-3]thymidine incorporati
on, TGF beta 1 and TGF beta 2 at 0.1-0.5 ng/ml and TGF beta 3 at 0.1-2
.5 ng/ml significantly stimulated the rate of [H-3]thymidine incorpora
tion into quiescent stromal cells (P < 0.005); they were ineffective a
t higher concentrations. TGF beta s did not have any effect on cell pr
oliferation, as determined by cell counting; however, at 0.1 ng/ml and
higher concentrations, TGF beta s significantly reduced the metabolic
activity of stromal cells, as determined by colorimetric -(4,5-dimeth
ylthiazol-2-yl)2,5-diphenyltetrazolium bromide assay (P < 0.05). The s
timulatory and inhibitory actions of TGF beta s in both assays were re
versible using 5-10 mu g/ml TGF beta 1- and TGF beta 2- and 3-6 mu g/m
l TGF beta 3-specific neutralizing antibodies. TGF beta 1 at 1 ng/ml h
ad no significant effect on long-lived protein degradation, assayed by
incorporation of [C-14]valine into newly synthesized protein by strom
al cells, and was similar to the effect of epidermal growth factor or
platelet-derived growth factor-BB (10 ng/ml). The data suggest that th
e TGF beta expression by various endometrial cell types in an autocrin
e/paracrine manner acts as a negative regulator essential for restrain
ing endometrial growth and transition from proliferation to differenti
ation stages during the secretory phase after mitogenic stimulation du
ring the proliferative phase of the menstrual cycle.