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PubMed2002

Localization of transforming growth factor beta2 (TGFbeta2) and its receptors, TbetaRI and TbetaRII, in uteri and blastocysts of the stripe-faced dunnart (Sminthopsis macroura) during gastrulation.

This study describes for the first time the spatial and temporal distribution of a growth factor and its receptors in uteri and conceptuses of a marsupial species during the peri-gastrulation period. Uteri (gravid and non-gravid) and blastocysts from 40 female stripe-faced dunnarts (Sminthopsis macroura) were collected over the peri-gastrula period (days 6.0-8.5) and stained immunohistochemically for transforming growth factor beta2 (TGFbeta2) and its receptors, TbetaRI and TbetaRII, to determine possible roles for TGFbeta2 in marsupial embryonic development. The events that occurred during the period examined included the appearance and proliferation of hypoblast and mesoderm, primitive streak and node formation, and early neurulation. Differences in TGFbeta2 quantities between gravid and non-gravid uteri reflect differences in uterine morphology, indicating a role for TGFbeta2 in endometrial remodelling. In blastocysts, large quantities of all three proteins in the trophectoderm during the node stage coincide with both blastocyst expansion before implantation and the appearance of multinucleated cells, indicating that TGFbeta2 plays a role in conceptus elongation and trophectoderm differentiation. In contrast, lack of TbetaRII in blastocysts during hypoblast formation and proliferation negates any role for TGFbeta2 in these processes, as both receptors are required for a response to TGFbeta2. High concentrations of TGFbeta2 but low concentrations of TbetaRII in blastocysts during early primitive streak formation indicate that paracrinal embryo-maternal signalling may be occurring, as blastocysts cannot respond to TGFbeta2 at this stage, but uteri could. A similar situation, but reversed, also occurs during primitive node formation.

Activin Receptors, Type I↗

PubMed2005

Control of human hair growth by neurotrophins: brain-derived neurotrophic factor inhibits hair shaft elongation, induces catagen, and stimulates follicular transforming growth factor beta2 expression.

Neurotrophins are important modulators of epithelial-mesenchymal interactions. Previously, we had shown that brain-derived neurotrophic factor (BDNF) and its high-affinity receptor tyrosine kinase B (TrkB) are prominently involved in the control of murine hair follicle cycling. We now show that BDNF and TrkB are also expressed in the human hair follicle in a manner that is both hair cycle dependent and suggestive of epithelial-mesenchymal cross-talk between BDNF-secreting dermal papilla fibroblasts of anagen hair follicles and subpopulations of TrkB+ hair follicle keratinocytes. As functional evidence for an involvement of BDNF/TrkB in human hair growth control, we show in organ-cultured human anagen hair follicles that 50 ng per mL BDNF significantly inhibit hair shaft elongation, induce premature catagen development, and inhibit keratinocyte proliferation. Quantitative real-time rtPCR analysis demonstrates upregulation of the potent catagen inducer, transforming growth factor beta2 (TGFbeta2) by BDNF, whereas catagen induction by BDNF was partially reversible through co-administration of TGFbeta-neutralizing antibody. This suggests that TrkB-mediated signaling promotes the switch between anagen and catagen at least in part via upregulation of TGFbeta2. Thus, human scalp hair follicles are both a source and target of bioregulation by BDNF, which invites to target TrkB-mediated signaling for therapeutic hair growth modulation.

Antibodies↗

PubMed2002

Transforming growth factor beta2 inhibits adipocyte differentiation induced by skeletal unloading in rat bone marrow stroma.

Skeletal unloading induced by hindlimb suspension in rats reduces bone formation and induces osteopenia, but its effect on adipogenesis is unknown. We assessed the effects of unloading and transforming growth factor (TGF) beta2 on bone marrow stromal cell adipocyte differentiation in relation with osteoblast differentiation. Skeletal unloading rapidly (4-7 days) decreased osteoblast transcription factor Runx2, osteocalcin (OC), and type I collagen messenger RNA (mRNA) levels and reduced bone formation in the long bone metaphysis. Conversely, unloading increased expression of the adipocyte transcription factor peroxisome proliferator-activated receptor gamma2 (PPARgamma2) at 4 days and increased expression of the adipocyte differentiation genes lipoprotein lipase (LPL) and aP2 in the bone marrow stroma at 7 days. Consistently, unloading increased the number and volume of adipocytes in the bone marrow stroma. Continuous (0-7 days) and late (4-7 days) treatments with TGF-beta2 corrected the abnormal expression of Cbfa1/Runx2, OC, and type I collagen mRNAs and normalized bone formation in unloaded metaphyseal bone. Moreover, both TGF-beta2 treatments decreased PPARy2 and C/EBPalpha mRNA levels at 4 days and normalized aP2 and LPL expression and adipocyte number and volume at 7 days. These results show that skeletal unloading increases adipocyte differentiation concomitantly with inhibition of osteoblast differentiation. These abnormalities are prevented and reversed by TGF-beta2, suggesting a role for TGF-beta in the control of adipogenic differentiation in the bone marrow stroma.

Adipocytes↗

PubMed1997

Antisense oligonucleotides specific for transforming growth factor beta2 inhibit the growth of malignant mesothelioma both in vitro and in vivo.

Transforming growth factor beta (TGF-beta) is a potent growth-regulatory and immunomodulatory cytokine that exerts a diverse range of effects on many types of cells. High levels of TGF-beta are produced by several human and mouse malignant mesothelioma (MM) cell lines, and it is known to act as a growth factor for these cells. Antisense oligonucleotides (ODNs), targeted against specific TGF-beta mRNA, were used to block TGF-beta production from MM cells in vitro and in vivo. TGF-beta antisense ODNs were encapsulated in liposomes and transfected into MM cells or delivered intratumorally. TGF-beta2 mRNA levels, assessed by semiquantitative PCR, and TGF-beta2 protein secretion were reduced after TGF-beta2 antisense ODN transfection. MM cell proliferation, assessed by tritiated thymidine uptake, was specifically inhibited by both TGF-beta1- and TGF-beta2-specific antisense ODNs. In vivo administration of TGF-beta2 antisense ODNs, delivered locally, reduced tumor growth. These data show that the blockade of TGF-beta2 within this tumor reduces tumor growth and raises the possibility that TGF-beta2 antisense ODNs may be useful as a therapy for this disease.

Animals↗

PubMed2006

An improved recombinant mammalian cell expression system for human transforming growth factor-beta2 and -beta3 preparations.

Transforming growth factor-beta2 and -beta3 (TGF-beta2 and -beta3) are important members of TGF-beta family which play important roles in the growth, maintenance, and repair processes of developing embryos, neonates, and adults. Preparation of large quantities of these two cytokines, which is necessary for structural studies and other applications, has proven to be extremely difficult. We have developed a novel Chinese hamster ovary cell-based expression system for high-level expression and high recovery of recombinant human TGF-beta2 and -beta3. In this system, we used a mammalian expression vector which contains a glutamine synthetase coding region for amplification, together with a modified TGF-beta2 or -beta3 open reading frame for expression. The leader peptide of TGF-beta2 or -beta3 was replaced by that from the V-J2-C region of a mouse immunoglobulin kappa-chain, and a poly-histidine tag was inserted immediately after the leader sequence to facilitate protein purification without changing the mature TGF-beta2 or -beta3 amino acid sequence. In addition, the extreme N-terminal cysteine residue of TGF-beta2 or -beta3 was replaced by a serine residue. The resulting expression constructs produced two stable cell clones expressing 10 mg of TGF-beta2 and 8 mg of TGF-beta3 per liter of spent medium. The purification scheme involved the use of two simple chromatographic steps with a typical yield of 5 mg of TGF-beta2 and 4 mg of TGF-beta3. This method represents a significant improvement over previously published methods and may be applicable to other TGF-beta superfamily members. We further confirmed that latent TGF-beta2 and -beta3 can be activated by proteolysis and glycolysis, which have not been reported before.

Animals↗

PubMed2002

Soluble Fas ligand and transforming growth factor beta2 in the aqueous humor of patients with endothelial immune reactions after penetrating keratoplasty.

BACKGROUND: Excellent long-term prognosis of penetrating corneal grafts has been explained by the immunological privilege of the cornea and the anterior chamber. In animal models the secretion of transforming growth factor beta(2) (TGF-beta(2)) into the anterior chamber and the expression of the Fas ligand on corneal endothelial cells were identified as important for the integrity of the immunological privilege. OBJECTIVE: To determine the TGF-beta(2) and soluble Fas ligand (sFasL) levels in the aqueous humor of patients after penetrating keratoplasty (PK) who have and who do not have immune reactions. METHODS: Anterior chamber puncture was performed in 13 patients who had a cataract without PK (group 1), in 31 patients after PK who did not have immune reactions (group 2), and in 12 patients after PK newly diagnosed as having endothelial immune reactions (group 3). Total TGF-beta(2) and sFasL were determined via enzyme-linked immunosorbent assay. RESULTS: Transforming growth factor beta(2) was detected in all patients, irrespective of the underlying condition; there was no difference in TGF-beta(2) levels between the different groups (P =.89, analysis of variance). None of the patients in group 1, 11 of 31 patients in group 2, and 8 of 12 patients in group 3 had detectable sFasL concentrations (P =.002, chi(2) test). Soluble Fas ligand averaged (mean [SD]) 20.8 (31.1) pg/mL in group 2, and 38.1 (33.2) pg/mL (P<.01, analysis of variance) in group 3. CONCLUSIONS: It appears that total TGF-beta(2) is maintained at high steady-state levels, while the level of sFasL is up-regulated in patients who underwent PK, particularily in the advent of graft rejection.

Aged↗

PubMed2002

Transforming Growth Factor-beta2 protects the small intestine during methotrexate treatment in rats possibly by reducing stem cell cycling.

During chemo- and radiation therapy, the balance between epithelial cell proliferation, differentiation, and cell death at the villus tip is disrupted by premature death of dividing epithelial cells. This will subsequently lead to the onset of mucosal barrier injury in the whole gastrointestinal tract. Up till now there is no validated method to treat side effects occurring due to therapy. An approach to manage this side effect might be to reversibly arrest growth of epithelial stem cells during therapy using Transforming Growth Factor-beta2. A Transforming Growth Factor-beta2 enriched fraction prepared from bovine milk was shown to protect small intestinal epithelial cells against cell cycle specific chemotherapeutic agents by arresting the cells in G1-phase. Secondly, in a rat model for induced small intestinal damage, oral supplementation of rats exposed to methotrexate with the Transforming Growth Factor-beta2 enriched fraction significantly reduced the chemotherapy-associated weight loss and ileal villus atrophy by reducing cell proliferation in the normal stem cell population. Thus oral supplementation with a bovine milk fraction enriched for Transforming Growth Factor-beta2 attenuated the side effects of chemotherapy in the small intestine in rats.

Administration, Oral↗

PubMed2003

Association of INOS, TRAIL, TGF-beta2, TGF-beta3, and IgL genes with response to Salmonella enteritidis in poultry.

Several candidate genes were selected, based on their critical roles in the host's response to intracellular bacteria, to study the genetic control of the chicken response to Salmonella enteritidis (SE). The candidate genes were: inducible nitric oxide synthase (INOS), tumor necrosis factor related apoptosis inducing ligand (TRAIL), transforming growth factor beta2 (TGF-beta2), transforming growth factor beta3 (TGF-beta3), and immunoglobulin G light chain (IgL). Responses to pathogenic SE colonization or to SE vaccination were measured in the Iowa Salmonella response resource population (ISRRP). Outbred broiler sires and three diverse, highly inbred dam lines produced 508 F1 progeny, which were evaluated as young chicks for either bacterial load isolated from spleen or cecum contents after pathogenic SE inoculation, or the circulating antibody level after SE vaccination. Fragments of each gene were sequenced from the founder lines of the resource population to identify genomic sequence variation. Single nucleotide polymorphisms (SNP) were identified, then PCR-RFLP techniques were developed to genotype the F1 resource population. Linear mixed models were used for statistical analyses. Because the inbred dam lines always contributed one copy of the same allele, the heterozygous sire allele effects could be assessed in the F1 generation. Association analyses revealed significant effects of the sire allele of TRAIL-StyI on the spleen (P <0.07) and cecum (P <0.0002) SE bacterial load. Significant effects (P <0.04) were found on the cecum bacterial load for TGF-beta3-BsrI. Varied and moderate association was found for SE vaccine antibody response for all genes. This is the first reported study on the association of SNP in INOS, TRAIL, TGF-beta2, TGF-beta3, and IgL with the chicken response to SE. Identification of candidate genes to improve the immune response may be useful for marker-assisted selection to enhance disease resistance.

Animals↗

PubMed2005

Diminished transforming growth factor beta2 production leads to increased expression of a profibrotic procollagen alpha2 type I messenger RNA variant in embryonic fibroblasts of UCD-200 chickens, a model for systemic sclerosis.

OBJECTIVE: A procollagen alpha2(I) messenger RNA (mRNA) variant, with a 115-bp band and an expected band of 180 bp, was found to be increased during early, acute scleroderma-like disease in UCD-200 chickens. The present study investigated the influence of cytokines on the expression of these 2 proalpha2(I) mRNA variants. METHODS: Embryonic fibroblasts of UCD-200 chickens (UCD-200-CEF) and normal white leghorns (NWL-CEF) were grown in 3-dimensional collagen gels. Procollagen mRNA expression was analyzed by RNase protection assay, and proliferation was determined by (3)H-thymidine incorporation. Transforming growth factor beta1 (TGFbeta1) and TGFbeta2 were measured in culture supernatants by enzyme-linked immunosorbent assay. RESULTS: Compared with NWL-CEF, UCD-200-CEF expressed 7.2 times more of the smaller profibrotic proalpha2(I) mRNA variant. TGFbeta1 stimulated the proliferation of UCD-200-CEF, but not NWL-CEF. The 115 bp:180 bp ratio was increased by TGFbeta1 in both NWL-CEF and UCD-CEF. TGFbeta2 and TGFbeta3 reduced the expression of the profibrotic proalpha2(I) mRNA in UCD-200-CEF to the same levels observed in healthy control NWL-CEF. In culture supernatants, NWL-CEF produced 4.1 times more TGFbeta2 than that produced by UCD-CEF. Inhibition of endogenous TGFbeta2 in NWL-CEF resulted in the same 115 bp:180 bp ratio as seen in untreated UCD-CEF. CONCLUSION: TGFbeta2 reduces the expression of a profibrotic proalpha2(I) mRNA variant in UCD-200-CEF. The constitutive overproduction of this proalpha2(I) mRNA variant and the diminished synthesis of TGFbeta2 in untreated UCD-200-CEF suggest that TGFbeta2 can act as an antifibrotic cytokine and might be a key player during fibrosis onset. These results shed light on the contradictory observations regarding the role of TGFbeta2 in human systemic sclerosis.

Animals↗

PubMed1996

Tumor necrosis factor alpha enhances secretion of transforming growth factor beta2 in MCF-7 breast cancer cells.

We studied the effect of tumor necrosis factor alpha (TNF-alpha) on transforming growth factor beta (TGF-beta) secretion by human breast cell lines to further characterize the antitumor effects of TNF-alpha. We found that TNF-alpha increased the secretion of TGF-beta in two established breast cancer cell lines (MCF-7 and ZR-75-1) but not in two immortalized human mammary epithelial cell lines (184B5 and MCF-10A). In MCF-7 cells, TNF-alpha increased the secretion of total TGF-beta 6.1-fold within 72 h in a dose-dependent manner. The secretion of both latent and active forms of TGF-beta was increased, and their ratio altered from 25:1 to 12:1 in the medium. TNF-alpha converted the secretory pattern of TGF-beta by MCF-7 cells from the heterodimeric form TGF-beta1.2 to the homodimeric form TGF-beta2. Immunoblot analysis under nonreducing conditions identified four molecular mass species of TGF-beta secreted in the culture media of untreated MCF-7 cells (238, 210, 40-55, and 25 kDa). Under reducing conditions, three molecular mass species of TGF-beta were identified: 88, 44, and 12 kDa. Gel filtration analysis demonstrated that the secreted TGF-beta within the range of 12-88 kDa was biologically active. TNF-alpha treatment did not alter the size of molecular mass species secreted by MCF-7 cells and did not change steady-state levels of mRNA for TGF-beta1 or TGF-beta2. These findings indicate that TNF-alpha may regulate quantitatively and qualitatively TGF-beta secretion by human breast cancer cells in vitro. The diverse biological activities of TGF-beta may also allow TNF-alpha to regulate the growth and metabolism of human mammary epithelial cells and/or stromal cells in a paracrine manner.

Breast Neoplasms↗

PubMed2000

Transforming growth factor beta2 inhibition of hepatocyte growth factor-induced endothelial proliferation and migration.

Angiogenesis is a highly controlled event which depends on the proper equilibrium of activators and inhibitors present within the microenvironment. Hepatocyte Growth Factor (HGF) activates migration and proliferation of endothelial cells and is angiogenic, acting through the tyrosine kinase receptor encoded by the Met protooncogene. To get insights into the molecular mechanisms involved in HGF-induced angiogenesis, we searched for cDNAs differentially expressed in human endothelial cells exposed to HGF, a potent angiogenic factor. We found that HGF-treated endothelial cells upregulated the expression of Transforming Growth Factor (TGF) beta2. To understand the significance of this finding, we cultured endothelial cells with HGF and TGF beta2 simultaneously. We found that TGF beta2 impairs HGF-dependent proliferative and migratory responses. TGF beta2 did not prevent the tyrosine phosphorylation of Met, but it inhibited some signalling pathways activated by HGF. We show that endothelial proliferation induced by HGF required the activation of the MAPK cascade, while HGF-induced endothelial migration was dependent on the tyrosine phosphorylation of Src. Indeed, TGF beta2 inhibited HGF effects because it prevented HGF-induced MAP kinase activation and tyrosine phosphorylation of Src. We suggest that the induction of TGF beta2 by HGF in endothelial cells may represent a physiologic mechanism to counterbalance HGF angiogenic activity.

Cell Division↗

PubMed2000

Transforming growth factor beta2 promotes glucose carbon incorporation into nucleic acid ribose through the nonoxidative pentose cycle in lung epithelial carcinoma cells.

The invasive transformation of A-459 lung epithelial carcinoma cells has been linked to the autocrine regulation of malignant phenotypic changes by transforming growth factor beta (TGF-beta). Here we demonstrate, using stable 13C glucose isotopes, that the transformed phenotype is characterized by decreased CO2 production via direct glucose oxidation but increased nucleic acid ribose synthesis through the nonoxidative reactions of the pentose cycle. Increased nucleic acid synthesis through the nonoxidative pentose cycle imparts the metabolic adaptation of nontransformed cells to the invasive phenotype that potentially explains the fundamental metabolic disturbance in tumor cells: highly increased nucleic acid synthesis despite hypoxia and decreased glucose oxidation.

Adenocarcinoma↗

PubMed1999

Transforming growth factor beta2 is able to modify mRNA levels and release of luteinizing hormone-releasing hormone in a immortalized hypothalamic cell line (GT1-1).

On the basis of our previous observations which indicated that transforming growth factor beta1 (TGFbeta1) affects the gene expression and the release of luteinizing hormone-releasing hormone (LHRH) in GT1-1 cells, we have presently evaluated whether also TGFbeta2 might be effective on these parameters. The data here reported show that also TGFbeta2 is able to affect LHRH dynamics, and that this action presents a different kinetics than that reported by TGFbeta1. In particular TGFbeta2 is able to facilitate LHRH release and to decrease the mRNA levels of this decapeptide. The present data have also shown that, GT1-1 cells express the messengers for the two most important receptors of the TGFbeta family, namely TGFbetaRI and TGFbetaRII and consequently represent a target for the action of the different isoforms of TGFbeta. Since the two isoforms of TGFbeta are produced and released from astrocytes, the present data add new support to the hypothesis that astrocytes participate in the control of LHRH secretion in a paracrine fashion.

Activin Receptors, Type I↗

PubMed2006

Transforming growth factor beta2 autocrinally mediates neuronal cell death induced by amyloid-beta.

Amyloid beta (Abeta), the major component of the senile plaques of Alzheimer's disease, is implicated in neuronal cell death. We have found that Abeta42, a neurotoxic form of Abeta peptide, induces both neuronal and glial expression of TGFbeta2. We have further demonstrated that the addition into culture media of neutralizing antibody to TGFbeta2 or a large amount of the recombinant soluble amyloid precursor protein alpha, the extracellular domain of amyloid precursor protein (APP) generated by alpha secretase, suppresses death in primary cortical neurons (PCNs) induced by Abeta42 in vitro. Combined with the finding in our recent study indicating that TGFbeta2 is a neuronal cell death-inducing ligand for APP, it is suggested that TGFbeta2 is an autocrinal mediator for Abeta42-induced death in PCNs.

Amyloid beta-Peptides↗

PubMed2004

Tissue-engineered trachea from sheep marrow stromal cells with transforming growth factor beta2 released from biodegradable microspheres in a nude rat recipient.

OBJECTIVE: The purpose of this study was to evaluate the feasibility of using autologous sheep marrow stromal cells cultured onto polyglycolic acid mesh to develop helical engineered cartilage equivalents for a functional tracheal replacement. We also explored the potential benefit of local delivery of transforming growth factor beta 2 with biodegradable gelatin microspheres. METHODS: Bone marrow was obtained by iliac crest aspiration from 6-month-old sheep and cultured in monolayer for 2 weeks. At confluence, the cells were seeded onto nonwoven polyglycolic acid fiber mesh and cultured in vitro with transforming growth factor beta 2 and insulin-like growth factor 1 for 1 week. Cell-polymer constructs were wrapped around a silicone helical template. Constructs were then coated with microspheres incorporating 0.5 microg transforming growth factor beta 2. The cell-polymer-microsphere structures were then implanted into a nude rat. On removal, glycosaminoglycan content and hydroxyproline were analyzed in both native and tissue-engineered trachea. Histologic sections of both native and tissue-engineered trachea were stained with hematoxylin and eosin, safranin-O, and a monoclonal anti-type II collagen antibody. RESULTS: Cell-polymer constructs with transforming growth factor beta 2 microspheres formed stiff cartilage de novo in the shape of a helix after 6 weeks. Control constructs lacking transforming growth factor beta 2 microspheres appeared to be much stiffer than typical cartilage, with an apparently mineralized matrix. Tissue-engineered trachea was similar to normal trachea. Histologic data showed the presence of mature cartilage. Glycosaminoglycan and hydroxyproline contents were also similar to native cartilage levels. CONCLUSIONS: This study demonstrates the feasibility of engineering tracheas with sheep marrow stromal cells as a cell source. Engineering the tracheal equivalents with supplemental transforming growth factor beta 2 seemed to have a positive effect on retaining a cartilaginous phenotype in the newly forming tissue.

Absorbable Implants↗

PubMed2000

Transforming growth factor beta2, but not beta1 and beta3, is critical for early rat lung branching.

Mesenchymal-epithelial tissue interactions are critical for lung branching morphogenesis, and polypeptide growth factors are likely involved in these tissue interactions. Transforming growth factorbetas (TGFbetas) have been implicated in lung development, but their involvement in early lung branching morphogenesis is unclear. In the present study, we investigated the role of the three mammalian TGFbeta subtypes (beta1, beta2, and beta3) and their receptors (type III (TbetaR-III), type II (TbetaR-II), and two types I (TbetaR-I), ALK-1 and ALK-5) in early rat lung organogenesis by using an embryonic rat lung explant culture. Transcripts and proteins for all three TGFbetas and their receptors were detected during the embryonic period of fetal rat lung development. Inhibition of TGFbeta2, but not beta1 and beta3, with antisense oligonucleotides and neutralizing antibodies resulted in significant inhibition of early lung branching in culture. Addition of minute amounts (</=1 ng/ml) of exogenous TGFbeta2, but not beta1 and beta3, restored the branching of TGFbeta2 antisense-treated explants. Higher concentrations of TGFbeta2 were inhibitory. BrdU labeling of lung explants was not altered by antisense TGFbeta2 treatment, but low concentrations of TGFbeta2 increased thymidine uptake by isolated epithelial cells. Fibronectin and metallogelatinase activities of embryonic lung cells were not affected by any TGFbeta isoform but TGFbeta2 specifically decreased mesenchymal hyaluronan synthesis. Antisense inhibition of ALK-5 and TbetaR-II showed a similar reduction in early lung branching as observed with antisense TGFbeta2. Incubation of lung explants with soluble TbetaR-II receptors also abrogated lung branching. ALK-1 antisense treatment did not affect early branching. Administration of neither activin A, which can act via ALK-1, nor follistatin, the natural inhibitor of activin, to the explants cultures had any significant effect on lung branching. Antisense inhibition of the activin receptor-II (Act-RII) also did not affect lung branching. These results are consistent with TGFbeta2, but not beta1 and beta3, regulating pattern formation during early rat lung organogenesis. This TGFbeta signaling in rat lung branching in vitro appears to be predominantly mediated via the TbetaR-I(ALK-5)/TbetaR-II heteromeric complex.

Activin Receptors, Type I↗

PubMed2000

Growth regulation of bovine retinal pericytes by transforming growth factor-beta2 and plasmin.

PURPOSE: Transforming growth factor -beta2 (TGF-beta2) is a predominant isoform of TGF-betas in the eye and plasmin is a peptidase with many functions. To better understand the pathogenesis of retinal microcirculation disorders, the effects of TGF-beta2 and plasmin on cultured bovine retinal pericytes were investigated. METHODS: Exogenous TGF-beta2 or plasmin was added to some cultures, DNA synthesis during cell cycle progression was investigated using [(3)H]thymidine incorporation. Anti-TGF-beta2 antibody was added to neutralize the effects of TGF-beta2. TGF-beta2 in the culture medium was measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: Exogenous TGF-beta2 (10 pg to 100 ng/mL) suppressed DNA synthesis. Pericytes produced TGF-beta2. Anti-TGF-beta2 antibody neutralized TGF-beta2 and accelerated DNA synthesis, which shows that pericytes regulate their own cell cycle by action of the autocrine and/or paracrine system of TGF-beta2. Plasmin (0.2 to 0.5 U/mL) accelerated DNA synthesis in a dose-dependent manner, while addition of aprotinin, a protease inhibitor, counteracted this effect of plasmin. The concentration of TGF-beta2 in the culture medium decreased with the addition of plasmin. Simultaneous addition of both plasmin and anti-TGF-beta2 antibody accelerated DNA synthesis. High and low glucose concentrations of the culture medium did not affect DNA synthesis. CONCLUSIONS: Our results suggest that TGF-beta2 and plasmin respectively decrease and increase DNA synthesis. In a retinal microcirculation disorder, they may play competitive roles in the cell cycle of pericytes.

Animals↗

PubMed1997

Differential effects of transforming growth factor beta2, dexamethasone and 1,25-dihydroxyvitamin D on human bone marrow stromal cells.

We have studied the effects of rhTGF-beta2, dexamethanosome (dex) and 1,25(OH)2D3 on human bone marrow stromal (HBMS) cells in long-term culture. A fraction on HBMS expressed type I collagen (Col I) and osteopontin, and transient treatment (48 h) with dex increased the number of alkaline phosphatase (ALP) positive cells. Treatment with rhTGF-beta2 inhibited DNA synthesis and attenuated the stimulatory effect of dex on cell growth at 3-4 weeks of culture. 1,25(OH)2D3 inhibited DNA synthesis at 1-4 weeks, and dex partially blocked the inhibitory effect of 1,25(OH)2D3 on cell growth. rhTGF-beta2 and dex increased Col I synthesis at 1 week of culture. Both dex and 1,25(OH)2D3 increased ALP activity and mRNA levels independently, and when combined they had an additive or synergistic effect, whereas rhTGF-beta2 antagonized the stimulatory effect of dex on ALP activity. In addition, dex attenuated the increased osteocalcin expression induced by 1,25(OH)2D3. These results show that rhTGF-beta2, dex and 1,25(OH)2D3 have distinct effects and modulate the action of each other on human marrow stromal cell proliferation and differentiation at different time points during the culture.

Aged↗