Platelet derived growth factor (PDGF) stimulates development of bovine embryos during the fourth cell cycle

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 821-826 ◽  
Author(s):  
R.C. Larson ◽  
G.G. Ignotz ◽  
W.B. Currie

In vitro produced, 2-cell bovine embryos were cultured in serum-free medium supplemented with various combinations of growth factors to test the hypothesis that these polypeptide factors are able to signal preimplantation development. The developmental arrest that occurs during the 8-cell stage with typical culture methods might be relieved by a growth factor-dependent mechanism that would stimulate expression of the embryonic genome, thereby mimicking events that occur in vivo in the oviduct during the fourth cell cycle (8- to 16-cell stage). Subsequently, other growth factors might promote compaction and blastulation, processes which normally occur in the uterus. The effects of growth factors on early embryos were evaluated using phase contrast microscopy to monitor progression to the 8-cell stage, completion and duration of the fourth cell cycle, and blastocyst formation. Platelet derived growth factor (PDGF) promoted development beyond the 16-cell stage in 39.1% of the 2-cell embryos examined in all experiments. The duration of the fourth cell cycle among these embryos was approximately 26 hours. During development after the 16-cell stage, PDGF reduced the proportion of embryos bastulating from 12.7% to 5.8%; in contrast, transforming growth factor alpha (TGF alpha), acting during the same developmental time period, increased the proportion of embryos blastulating from 8.6% to 40.6%. These results, using serum-free medium, indicated that PDGF signalled completion of the fourth cell cycle. TGF alpha, and perhaps basic fibroblast growth factor (bFGF), promoted blastulation of 16-cell embryos during subsequent culture.

1985 ◽  
Vol 73 (1) ◽  
pp. 375-387
Author(s):  
O. Larsson ◽  
A. Zetterberg ◽  
W. Engstrom

We have previously shown that Swiss 3T3 cells located in the first part of G1 (post-mitotic G1 cells younger than 4.0 h or G1pm cells) were arrested after 9–10 h in the cell cycle by a short (1-8 h) exposure to serum-free medium or by a short (2-4 h) exposure to low doses of the protein synthesis inhibitor cycloheximide (CH). Kinetic data indicate that such G1pm cells rapidly return to G0 during this brief treatment and thereafter require a preparatory period of 8 h before continuing to G1. Cells older than 4 h, i.e. cells in mid or late G1 are already committed to DNA synthesis (presynthesis or G1ps cells). These cells as well as S and G2 cells were consequently unaffected by the brief serum starvation or the brief treatment with cycloheximide. In the present paper we show that the 10-h intermitotic delay that follows a 1–2 h exposure to serum-free medium can be completely counteracted by the presence of any one of the purified growth factors, epidermal growth factor (EGF), insulin or platelet-derived growth factor (PDGF). In contrast, the intermitotic delay following a longer exposure (8 h) to serum-free medium could no longer be counteracted by EGF or insulin. However, PDGF was still active in this respect. Most interestingly, the 12 h gross intermitotic delay induced by a 4h exposure to CH could be efficiently counteracted by EGF, PDGF or insulin. However, this effect on CH-treated cells could be counteracted by the growth factor only in the presence of 10% serum. This indicates the existence of a cooperative effect between PDGF, EGF or insulin and an unidentified serum factor. The effects on the cell cycle time of brief serum starvation and exposure to CH were compared with the effects on rate of protein synthesis and degradation. Although the effects of serum starvation on protein synthesis and degradation were found to be partially normalized by growth factors, we suggest that growth factors prevent cells from leaving the cell cycle by another mechanism and not merely by affecting the level of overall protein accumulation.


1984 ◽  
Vol 103 (2) ◽  
pp. 195-203 ◽  
Author(s):  
D. J. Hill ◽  
R. D. G. Milner

ABSTRACT The actions of partially purified porcine platelet-derived growth factor (PDGF) and highly purified multiplication-stimulating activity (MSA) II and MSA III-2, which are somatomedins, were investigated on the incorporation of [3H]thymidine and [35S]sulphate by fetal rat costal cartilage in vitro. This was compared with their effects in the presence of 1% fetal calf serum (FCS) on the uptake of thymidine by growth-arrested fetal rat fibroblasts. Platelet-derived growth factor at concentrations of 0·21–21 μg/l enhanced the incorporation of both isotopes by fetal cartilage in the presence of 1% FCS, but had an inconsistent action on thymidine uptake and no significant action on sulphate uptake in serum-free medium. Platelet-derived growth factor promoted thymidine uptake by growth-arrested, isolated fetal rat fibroblasts. Multiplication-stimulating activity II (10–100 μg/l) stimulated the uptake of thymidine and sulphate by fetal cartilage in medium containing 1% FCS but had no consistent action in serum-free medium, although MSA II and PDGF had a synergistic effect on thymidine uptake in the absence of serum. Multiplication-stimulating activity III-2 had no consistent action on thymidine or sulphate incorporation by fetal cartilage in either serum-free or serum-supplemented medium. However, the same preparation of MSA III-2 stimulated the uptake of [3H]thymidine into fetal rat fibroblasts with a half-maximal response at a concentration of 5–10 μg/l. The results identify PDGF as a possible mitogenic agent for fetal rat connective tissues in vitro and show a differential sensitivity of fetal cartilage to MSA peptides. J. Endocr. (1984) 103, 195–203


1992 ◽  
Vol 12 (9) ◽  
pp. 3883-3889
Author(s):  
Z Pietrzkowski ◽  
C Sell ◽  
R Lammers ◽  
A Ullrich ◽  
R Baserga

BALB/c3T3 cells are exquisitely growth regulated and require platelet-derived growth factor, epidermal growth factor (EGF), and insulinlike growth factor 1 (IGF-1) for growth. When BALB/c3T3 cells are transfected with plasmids constitutively expressing both EGF and the human IGF-1 receptor mRNAs, the cells are capable of growing in serum-free medium without the addition of any exogenous growth factor. These cells, called p5 cells, can grow for prolonged periods in serum-free medium. BALB/c3T3 cells transfected with only the IGF-1 receptor expression plasmid (p6 cells) do not grow in serum-free medium but do grow if IGF-1 (or insulin in supraphysiological concentrations) is added. p6 cells also grow in response to EGF, confirming that the combination of EGF and an overexpressed IGF-1 receptor is sufficient for the growth of 3T3 cells. We have found that in EGF-stimulated p6 cells there is an increase in the expression of IGF-1 mRNA, that IGF-1 is secreted into the medium, and that the growth of p5 cells and EGF-stimulated p6 cells is inhibited by exposure to antisense oligodeoxynucleotides to IGF-1 receptor RNA. Finally, while cells constitutively expressing both EGF and EGF receptor RNAs grow, albeit modestly, in serum-free medium, their growth is also inhibited by an antisense oligodeoxynucleotide to IGF-1 receptor RNA. In contrast, in cells overexpressing the IGF-1 receptor, IGF-1-mediated cell growth occurs independently of the platelet-derived growth factor and EGF receptors (Z. Pietrzkowski, R. Lammers, G. Carpenter, A. M. Soderquist, M. Limardo, P. D. Phillips, A. Ullrich, and R. Baserga, Cell Growth Differ. 3:199-205, 1992, and this paper). These data indicate that an important role for EGF is participation in the activation of an autocrine loop based on the IGF-1-IGF-1 receptor interaction, which is obligatory for the proliferation of 3T3 cells.


1994 ◽  
Vol 107 (9) ◽  
pp. 2459-2469 ◽  
Author(s):  
P.A. Campochiaro ◽  
S.F. Hackett ◽  
S.A. Vinores ◽  
J. Freund ◽  
C. Csaky ◽  
...  

The retinal pigmented epithelium (RPE) plays a major role in normal and exaggerated retinal wound repair; the latter can result in epiretinal membrane formation and loss of vision. The RPE forms a stable monolayer of highly differentiated cells that proliferates only during wound repair. The mechanism underlying the change to the proliferating phenotype is unknown. When grown on a plastic substratum, cultured RPE cells mimic the proliferating phenotype in situ; they escape density arrest and proliferate in serum-free medium. In this study, we have demonstrated that a platelet-derived growth factor (PDGF) autocrine loop is involved in RPE growth in serum-free medium, because: (1) RPE cells secrete PDGF into their media and express PDGF receptors; (2) the PDGF receptors on RPE cells are autophosphorylated in serum-free medium and suramin, an agent that displaces PDGF and other growth factors from their receptors, blocks the autophosphorylation; and (3) a neutralizing antibody to PDGF significantly decreases RPE growth in serum-free medium. When a linear scrape is made in an RPE monolayer, the cells migrate and proliferate to fill in the gap mimicking wound repair in situ. Cells along the edge of the scrape show increased expression of PDGF and PDGF-beta receptors, and increased staining for proliferating cell nuclear antigen. Immunohistochemistry and in situ hybridization demonstrate expression of PDGF in ganglion cells and cells of retinal blood vessels. PDGF is not detected in the outer retina or RPE in untreated eyes, but is detected in RPE participating in wound repair, either adjacent to laser burns or underlying retinal detachment. PDGF and PDGF receptors are also expressed in RPE in epiretinal membranes removed during vitreous surgery. These data suggest that PDGF is an autocrine stimulator of growth in RPE that plays a role in retinal wound repair and epiretinal membrane formation.


1991 ◽  
Vol 3 (1) ◽  
pp. 99 ◽  
Author(s):  
D Sakkas ◽  
AO Trounson

Co-culture of pre-implantation embryos with cells of the reproductive tract requires a medium that is beneficial to both embryos and cells. However, many studies in this area utilize media originally formulated for specific cell lines. In the present study, a complex serum-free medium (CSM) was formulated on the basis of the ionic compositions of existing embryo culture media and mouse oviductal fluid as well as the concentrations of growth factors that appear to benefit mouse embryo development. The study began by investigating the effect of altering the concentrations of K+ ions (0-40 mM) and sulfate ions (0-10 mM) in embryo culture media on the development of 2-cell mouse embryos. Mouse embryos showed improved cell numbers at the blastocyst stage when cultured in 10 mM K+ compared with Whittingham's T6 medium. Embryos were also cultured in T6 supplemented with bovine serum albumin (BSA) containing various concentrations of insulin, insulin-like growth factors I and II, fibroblast growth factor, and epidermal growth factor. Insulin concentrations of 100 ng mL-1 significantly (P less than 0.05) improved the cell numbers of 2-cell embryos cultured to the morulae and blastocyst stages compared with those cultured in T6 + BSA alone. CSM was formulated on the basis of the results of these experiments and was found to support both improved development of 2-cell mouse embryos and the culture of mouse fibroblast and mouse oviduct cells.


1980 ◽  
Vol 86 (2) ◽  
pp. 483-489 ◽  
Author(s):  
CC Johnson ◽  
WE Dawson ◽  
JT Turner ◽  
JH Wyche

A cultured rat ovarian cell line (31 A-F(2)) was used to study the effect of growth factors (epidermal growth factor [EGF] and fibroblast growth factor [FGF]), a survival factor (ovarian growth factor [OGF]), a hormone (insulin), and an iron-binding protein (transferring) on cell proliferation and steroid production under defined culture conditions. EGF and insulin were shown to be mitogenic (half-maximal response at 0.12 nM and 0.11 muM, respectively) for 31A-F(2) cells incubated in serum-free medium. EGF induced up to three doublings in the cell population, whereas insulin induced an average of one cell population doubling. FGF, OGF, and transferrin were found not to have any prominent effect on cell division when incubated individually with 31A-F(2) cells in serum-free medium. However, a combination of EGF, OGF, insulin, and transferrin stimulated cell division to the same approximate extent as cells incubated in the presence of 5 percent fetal calf serum. EGF or insulin did not significantly affect total cell cholesterol levels (relative to cells incubated in serum-free medium) when incubated individually with 31A-F(2) cells. However, cell cholesterol levels were increased by the addition of OGF (250 percent), FGF (370 percent), or a combination of insulin and EGF (320 percent). Progesterone secretion from 31A-F(2) cells was enhanced by EGF (25 percent), FGF (80 percent), and insulin (115 percent). However, the addition of a mitogenic mixture of EGF, OGF, insulin, and transferrin suppressed progesterone secretion 150 percent) below that of control cultures. These studies have permitted us to determine that EGF and insulin are mitogenic factors that are required for the growth of 31A-F(2) cells and that OGF and transferrin are positive cofactors that enhance growth. Also, additional data suggest that cholesterol and progesterone production in 31A-F(2) cells can be regulated by peptide growth factors and the hormone insulin.


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