Induction of stable microtubules in 3T3 fibroblasts by TGF-beta and serum

1994 ◽  
Vol 107 (3) ◽  
pp. 645-659 ◽  
Author(s):  
G.G. Gundersen ◽  
I. Kim ◽  
C.J. Chapin

Previous studies have shown that fibroblasts induced to migrate into an in vitro wound rapidly generate an array of stable, post-translationally detyrosinated microtubules (Glu MTs) oriented toward the direction of migration. To understand how cells generate a stable array of MTs at a specific location, we have analyzed the contribution of media components to the formation of oriented Glu MTs in wounded monolayers of 3T3 fibroblasts. When confluent monolayers were placed in serum-free medium (SFM) for 2 days before wounding, the cells contained virtually no Glu MTs or nocodazole-resistant MTs and were incapable of generating Glu MTs in response to wounding. Such SFM-treated monolayers were capable of generating oriented Glu MTs within 1 hour of wounding, if calf serum (CS) was added back to the medium. The Glu MTs in the CS refed cells were oriented toward the wound in cells at the wound edge, and were juxtanuclear in cells within the monolayer, demonstrating that CS restored the Glu MT array characteristic of each cell type. To determine the nature of the ‘Glu MT-inducing’ factor in CS, we subjected CS to different treatments and found that the CS factor was nondialyzable, resistant to heat, mild acid and trypsin, but inactivated by treatment with dithiothreitol. The factor was not absorbed by charcoal and was present in lipoprotein-deficient serum. These properties are consistent with the properties of a number of polypeptide growth factors, so we screened purified growth factors for their ability to induce Glu MTs in wounded SFM-treated monolayers. Of all the growth factors tested, only TGF-beta 1 and TGF-beta 2 induced a significant level (> or = 70% of the CS response) of oriented Glu MTs. The SFM-treated cells were exquisitely sensitive to TGF-beta 1, with significant induction of Glu MTs observed at 0.01 ng/ml TGF-beta 1. Induction of Glu MTs observed by immunofluorescence after CS or TGF-beta treatments were paralleled by increases in Glu tubulin detected on western blots. The Glu MTs formed after either CS or TGF-beta 1 treatment showed enhanced resistance to nocodazole, confirming that both treatments increased the level of stable MTs in cells. The TGF-beta 1 induction of stable MTs was slower than that of CS (2-4 hours onset versus 1 hour onset), but by 24 hours the level of MT stabilization in TGF-beta 1 was even greater than that in CS.(ABSTRACT TRUNCATED AT 400 WORDS)

2004 ◽  
Vol 181 (3) ◽  
pp. 477-492 ◽  
Author(s):  
AA Fouladi Nashta ◽  
CV Andreu ◽  
N Nijjar ◽  
JK Heath ◽  
SJ Kimber

Decidualisation of uterine stromal cells is a prerequisite for implantation of the embryo in mice. Here we have used an in vitro culture system in which stromal cells decidualise as indicated by a number of markers, including an increase in alkaline phosphatase (ALP) activity. The latter was used as a quantitative marker of decidualisation in the presence of low (2%) fetal calf serum. Prostaglandin E(2) (PGE(2)), which is known to induce decidualisation, increased ALP activity, and this effect was blocked in a dose-dependent manner by indomethacin. Leukemia inhibitory factor (LIF) was then examined, but it had no effect on PGE(2) secretion. However, LIF suppressed ALP activity in a dose-dependent manner in the presence of 2% serum, while an inhibitor of LIF that competes for binding to its receptor reversed the effect of LIF and increased ALP activity above the control level. In serum-free cultures, stromal cells differentiated rapidly, and no differences were observed between LIF-treated and untreated cultures. Stromal cells produce LIF during in vitro culture, and this peaked at 48 h. Freshly collected stromal cells from both day-2 and -4 pregnant mice expressed mRNA for the LIF receptor, and the transcript level was higher in cells isolated on day 4. However, no differences were observed in the relative levels of transcripts in cells from day 2 and day 4 after culture, nor were there differences between the LIF-treated cultures and controls. Therefore, in this study, we have shown that LIF suppresses decidualisation of murine uterine stromal cells in the presence of serum, this is not due to the regulation of PGE(2) secretion by stromal cells.


1994 ◽  
Vol 267 (6) ◽  
pp. E990-E1001 ◽  
Author(s):  
M. Slater ◽  
J. Patava ◽  
K. Kingham ◽  
R. S. Mason

Human fetal osteoblast-like cells formed a regular multilayered structure in vitro with an extensive collagen-based extracellular matrix. With colloidal gold immunocytochemistry, labels for alkaline phosphatase and osteocalcin were distributed in a relatively diffuse pattern, in contrast to the bone growth factors, insulin-like growth factors I and II (IGF-I and IGF-II), transforming growth factor-beta 1 (TGF-beta 1), and basic fibroblast growth factor, which were colocalized in the collagenous matrix of the multilayer. The inclusion of 17 beta-estradiol (10(-11) to 10(-9) M) in the culture medium increased multilayer depths, increased labeling for IGF-I, IGF-II, and TGF-beta 1, and resulted in earlier detection of TGF-beta 1 label. In contrast, the increase in multilayer depth resulting from treatment with human platelets, an exogenous source of growth factors, was not accompanied by an increase in matrix IGF-I, IGF-II, or TGF-beta 1 label, suggesting a particular effect of estradiol to facilitate this process. Because growth factors in bone matrix may act as coupling agents when released during resorption, reduced growth factor incorporation in the presence of reduced sex steroid concentrations may lead to uncoupling of resorption and subsequent formation.


Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 2871-2877 ◽  
Author(s):  
K Takenaka ◽  
K Nagafuji ◽  
M Harada ◽  
S Mizuno ◽  
T Miyamoto ◽  
...  

Fas antigen (Fas Ag; CD95) is a cell surface molecule that can mediate apoptosis. Bcl-2 is a cytoplasmic molecule that prolongs cellular survival by inhibiting apoptosis. To investigate the role of both molecules in hematopoiesis, we evaluated the expression of Fas Ag and Bcl-2 on CD34+ hematopoietic progenitor cells expanded in vitro. CD34+ cells isolated from bone marrow were cultured in iscove's modified Dulbecco's medium supplemented with 10% fetal calf serum, 1% bovine serum albumin, 50 ng/mL stem cell factor, 50 ng/mL interleukin-3 (IL-3), 50 ng/mL IL-6, 100 ng/mL granulocyte colony-stimulating factor, and 3 U/mL erythropoietin for 7 days. Colony-forming unit of granulocytes/macrophages (CFU-GM) and burst-forming unit of erythroids (BFU-E) were expanded 6.9-fold and 8.8-fold in number at day 5 of culture, respectively. Freshly isolated CD34+ cells did not express Fas Ag, whereas approximately half of them expressed Bcl-2. CD34+ cells cultured with hematopoietic growth factors gradually became positive for Fas Ag and rapidly lost Bcl-2 expression. Furthermore, apoptosis was induced in the cultured CD34+ population when anti-Fan antibody (IgM; 1 microgram/mL) was added, as shown by significant decrease in the number of viable cells, morphologic changes, induction of DNA fragmentation, and significant decrease in the number of clonogenic progenitor cells including CFU. GM and BFU-E. These results indicate that functional expression of Fas Ag is induced on CD34+ cells expanded in vitro in the presence of hematopoietic growth factors. Induction of Fas Ag and downregulation of Bcl-2 may be expressed as part of the differentiation program of hematopoietic cells and may be involved in the regulation of hematopoiesis.


1993 ◽  
Vol 104 (1) ◽  
pp. 69-76 ◽  
Author(s):  
R.P. Tucker ◽  
J.A. Hammarback ◽  
D.A. Jenrath ◽  
E.J. Mackie ◽  
Y. Xu

The glycoprotein tenascin is found in the extracellular matrix in regions of cell motility, cell proliferation, and tissue modelling. We have used novel tenascin cDNA probes to localize tenascin transcripts in the developing mouse and to study the regulation of tenascin expression by growth factors in vitro. At postnatal day 1 tenascin mRNAs are abundant in regions of bone and cartilage formation, as well as in the ependymal layer of the central nervous system. Previous studies have demonstrated that transforming growth factor-beta type 1 (TGF-beta 1) can induce tenascin expression in vitro. As TGF-beta 1 is absent or scarce in the developing brain, it is likely that other growth factors, alone or in addition to TGF-beta 1, may regulate tenascin expression during development. Therefore, we have compared the effects of TGF-beta 1 and a growth factor that is found in both developing connective tissue and the central nervous system, basic fibroblast growth factor (bFGF), on tenascin expression in a mouse embryo fibroblast cell line (Swiss 3T3 cells). Immuno-slot blot analysis of Swiss 3T3 cell-conditioned culture medium demonstrates that bFGF is a more potent inducer of tenascin expression than TGF-beta 1. Furthermore, bFGF and TGF-beta 1 have an additive effect on levels of tenascin, but not fibronectin, in the conditioned medium. Western blots revealed that different forms of tenascin are induced by bFGF and TGF-beta 1: the tenascin induced by the former has a molecular mass of approximately 250 kDa, the latter induces an approximately 200 kDa form of tenascin. The induction of large tenascin by bFGF was confirmed by northern blot analysis, which revealed increased levels of an 8 kb tenascin transcript after 24 h by as little as 4 ng/ml of bFGF in serum-free medium. Thus bFGF, alone or in combination with TGF-beta 1, is a potential regulator of tenascin expression in vitro. bFGF may alter not only the relative abundance of tenascin and fibronectin in the extracellular matrix, but also the splice variant of tenascin expressed by a given cell type.


Blood ◽  
1995 ◽  
Vol 86 (1) ◽  
pp. 283-293 ◽  
Author(s):  
R Ford ◽  
A Tamayo ◽  
B Martin ◽  
K Niu ◽  
K Claypool ◽  
...  

The molecular basis of neoplastic B-cell growth is complex and poorly understood. Cytokines have been postulated to contribute to neoplastic cell growth, and many in vitro studies have confirmed this prediction, but little is known about the in vivo role of these growth factors. We have examined the production of interleukin-14 (IL-14) (high molecular weight [HMW], B-cell growth factor [BCGF]) by aggressive intermediate (diffuse large cell) lymphomas of the B-cell type non-Hodgkin's lymphoma (NHL-B) in four patients with lymphomatous effusions. In these studies, IL-14 was detected in the effusion fluids by Western blots and IL-14 mRNA was constitutively expressed in the freshly isolated lymphoma cells that also expressed the receptor for IL-14 (IL14R). Lymphoma B cells placed at low serum and cell density proliferated in vitro to either purified IL-14 or IL-14 derived from effusion fluids. Antibodies to IL-14 removed the growth-stimulating cytokine(s) from the effusions. Cell lines developed from these patients produced IL-14 in vitro and antisense oligos to IL-14 blocked their growth in vitro. Thus, autocrine or paracrine production of IL-14 may play a significant role in the rapid proliferation of aggressive NHL-B. Interrupting this pathway could be a useful goal of therapy for patients resistant to conventional chemotherapy.


2005 ◽  
Vol 17 (9) ◽  
pp. 87
Author(s):  
L. S. Sleer ◽  
C. C. Taylor

In this study, the family of platelet derived growth factors (PDGF) and receptors were identified and characterized in the rat ovary and a role in contributing towards growth of preantral follicles was revealed. Real-time polymerase chain reaction revealed the presence of mRNA for all platelet derived growth factors (PDGF-A, PDGF-B, PDGF-C and PDGF-D) and receptors (PDGF-Rα and PDGF-Rβ). In situ hybridization identified oocytes of primordial/primary follicles and cells of the theca layer as a source of PDGF-B, PDGF-C and PDGF-D mRNA. Protein expression was explored through immunohistochemistry. In rats aged days 0 and 4, PDGF-Rα, PDGF-A and PDGF-C immunoreactivity was observed within oocyte clusters, and PDGF-Rβ and PDGF-B immunoreactivity in cells surrounding oocyte clusters. In primordial follicles, PDGF-Rβ and PDGF-C was observed in the oocyte, and PDGF-Rα and A in the either the oocyte or pregranulosa cells. In primary follicles, PDGF-A, PDGF-C, PDGF-Rα and PDGF-Rβ are expressed in the oocyte. PDGF-Rβ is also expressed in cells surrounding primordial and primary follicles, possibly the precursors to theca cells. In secondary and antral follicles, all four PDGF isoforms and both receptors are expressed in either theca or vascular cells of the theca layer, and PDGF-Rα and A are also expressed in some granulosa cells in rats aged day 20 and older. A role in preantral follicle growth was identified by in vitro culture of preantral follicles. Preantral follicles cultured in serum free medium increased in diameter by 11.0 ± 1.57% over 5 days. Addition of PDGF-AA, PDGF-AB or PDGF-BB to the medium resulted in increases in follicle diameter after 5 days of 18.32 ± 2.18%, 17.72 ± 2.3% and 17.6 ± 1.81%, respectively, representing a significant increase over control diameters. In summary, this study has identified and characterized the presence and localization of all members of the family of platelet derived growth factors and receptors in the rat ovary and revealed a role for these growth factors in positively influencing early follicle growth.


Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 1095-1101
Author(s):  
A.J. Muslin ◽  
L.T. Williams

The effect of growth factors on the formation of cardiac mesoderm in the urodele, Ambystoma mexicanum (axolotl), has been examined using an in vitro explant system. It has previously been shown that cardiac mesoderm is induced by pharyngeal endoderm during neurula stages in urodeles. In this study, explants of prospective cardiac mesoderm from early neurula stage embryos rarely formed beating cardiac tissue in culture. When transforming growth factor beta-1 (TGF-beta 1) or platelet-derived growth factor BB (PDGF) was added to such explants, the frequency of heart tissue formation increased markedly. The addition of other growth factors to these explants did not enhance cardiac mesoderm formation. The addition of basic fibroblast growth factor (bFGF) to prospective heart mesoderm derived from later stage embryos resulted in a decreased tendency to form cardiac tissue. These results suggest that growth factors analogous to TGF-beta 1, PDGF, and bFGF may regulate the initial stages of vertebrate cardiac development in vivo.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3534-3534
Author(s):  
E. Stellacci ◽  
A. Di Noia ◽  
A.R. Migliaccio ◽  
A. Battistini ◽  
G. Migliaccio

Abstract Glucocorticoids are capable to modulate erythroid differentiation in vivo and in vitro. The reversible inhibition exerted by these factors on the maturation of CD36high CD235alow pro-erythroblasts was exploited to establish HEMA, a culture system that allows massive production (108−10 cells) of erythroblasts from as little as 10 mL of adult peripheral blood (G. Migliaccio et al. Blood Cells Mol Dis28:169, 2002). How glucocorticoids block erythroid differentiation is not known. We hypothesized that this effect could be due to physical interaction of the glucocorticoid receptor (GR) either with the erythropoietin receptor (EPO-R), or with one of its downstream signalling partners. To test this hypothesis, CD36high CD235alow proerythroblasts were generated in HEMA culture, growth factor starved for up to 4 hrs and then stimulated either with EPO (3U/mL), Dexamethasone (DXM, 10−6M), or the combination of both, up to 4 hrs. Next, we undertook a series of immunoprecipitation (IP), followed by appropriate western blots (WB), of lysates from cells exposed to the different conditions. Both EPO and DXM rapidly (within 15 min) phosphorylated STAT-5, as shown by IP for STAT-5 followed by WB for P-STAT-5. In contrast, stimulation of the cells with both EPO and DXM for up to 4 hrs did not result in STAT-5 phosphorylation. On the other hand, IP with EPO-R was positive for EPO-R WB under all the conditions, but positive for P-STAT-5 WB and GR WB when cells were stimulated either with EPO or with DXM. The amount of GR detected by WB in EPO-R IP from cells stimulated with both EPO and DXM was greatly reduced (see Figure). In contrast, in STAT-5 IP, EPO-R was WB only in cells stimulated with EPO, P-STAT-5 was WB in cells treated with EPO or DXM, and GR was WB mainly in cells treated with DXM. In agreement with these results, IP for P-Tyr were positive for EPO-R only from cells treated with EPO, but were WB for GR with all the conditions. The fact that P-STAT-5 was WB in EPO-R IP from cells treated with EPO or with DXM, while EPO-R was WB in STAT-5 IP only from cells treated with EPO, is consistent with a model according to which, since EPO-R IP is positive for GR by WB, P-STAT-5 is IP with EPO as part of the EPO-R/GR/P-STAT-5 complex. These results suggest that EPO-R and GR are present in CD36high CD235alow cells stimulated with either EPO or DXM as a multicomplex, P-STAT-5 becames part of this complex in association with either EPO-R or GR, depending on the stimulus, EPO or DXM, to which the cells are exposed. Stimulation with both factors, leads to dissociation of the EPO-R/GR complex and neither of the two receptors is capable to stimulate phosphorylation of STAT-5. We propose that glucocorticoids interfere with erythroid differentiation by a non-genomic mechanism that involves physical interaction with EPO-R. Figure 1: Summary of the IP with EPO-R, STAT-5 and P-Tyr specific antibody processed by WB for EPO-R, P-STAT-5 and GR, as indicated. A model summarizing the results is described on the top. Figure 1:. Summary of the IP with EPO-R, STAT-5 and P-Tyr specific antibody processed by WB for EPO-R, P-STAT-5 and GR, as indicated. A model summarizing the results is described on the top.


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