Plasma Biomarkers of Risk of Tuberculosis Recurrence in HIV Co-Infected Patients From South Africa.

There is an urgent need to identify immunological markers of tuberculosis (TB) risk in HIV co-infected individuals. Previously we have shown that TB recurrence in HIV co-infected individuals on ART was associated with markers of systemic inflammation (IL-6, IL1ß and IL-1Rα). Here we examined the effect of additional acute inflammation and microbial translocation marker expression on risk of TB recurrence. Stored plasma samples were drawn from the TB Recurrence upon Treatment with HAART (TRuTH) study, in which individuals with previously treated pulmonary TB were screened for recurrence quarterly for up to 4 years. Recurrent TB cases (n = 37) were matched to controls (n = 102) by original trial study arm assignment and ART start date. Additional subsets of HIV infected (n = 41) and HIV uninfected (n = 37) individuals from Improving Recurrence Success (IMPRESS) study were sampled at active TB and post successful treatment completion. Plasma concentrations of soluble adhesion molecules (sMAdCAM, sICAM and sVCAM), lipopolysaccharide binding protein (LBP) and transforming growth factor-beta (TGF-ß1, TGF-ß2, TGF-ß3) were measured by multiplex immunoassays and ELISA. Cytokine data was square root transformed in order to reduce variability. Multivariable analysis adjusted for a number of potential confounders measured at sample time-point: age, BMI, CD4 count, viral load (VL) and measured at baseline: presence or absence of lung cavities, previous history of TB, and WHO disease stage (4 vs 3). The following analytes were associated with increased risk of TB recurrence in the multivariable model: sICAM (aOR 1.06, 95% CI: 1.02-1.12, p = 0.009), LBP (aOR 8.78, 95% CI: 1.23-62.66, p = 0.030) and TGF-ß3 (aOR 1.44, 95% CI 1.01-2.05, p = 0.044). Additionally, we observed a positive correlation between LBP and sICAM (r= 0.347, p<0.0001), and LBP and IL-6, identified to be one of the strongest predictors of TB risk in our previous study (r=0.623, p=0.03). These data show that increased risk of TB recurrence in HIV infected individuals on ART is likely associated with HIV mediated translocation of microbial products and the resulting chronic immune activation.

Identification of a novel transforming growth factor-beta (TGF-beta6) gene in fish: regulation in skeletal muscle by nutritional state.

BACKGROUND: The transforming growth factor-beta (TGF-beta) family constitutes of dimeric proteins that regulate the growth, differentiation and metabolism of many cell types, including that of skeletal muscle in mammals. The potential role of TGF-betas in fish muscle growth is not known. RESULTS: Here we report the molecular characterization, developmental and tissue expression and regulation by nutritional state of a novel TGF-beta gene from a marine fish, the gilthead sea bream Sparus aurata. S. aurata TGF-beta6 is encoded by seven exons 361, 164, 133, 111, 181, 154, and 156 bp in length and is translated into a 420-amino acid peptide. The exons are separated by six introns: >643, 415, 93, 1250, 425 and >287 bp in length. Although the gene organization is most similar to mouse and chicken TGF-beta2, the deduced amino acid sequence represents a novel TGF-beta that is unique to fish that we have named TGF-beta6. The molecule has conserved putative functional residues, including a cleavage motif (RXXR) and nine cysteine residues that are characteristic of TGF-beta. Semi-quantitative analysis of TGF-beta6 expression revealed differential expression in various tissues of adult fish with high levels in skin and muscle, very low levels in liver, and moderate levels in other tissues including brain, eye and pituitary. TGF-beta6 is expressed in larvae on day of hatching and increases as development progresses. A fasting period of five days of juvenile fish resulted in increased levels of TGF-beta6 expression in white skeletal muscle compared to that in fed fish, which was slightly attenuated by one injection of growth hormone. CONCLUSION: Our findings provide valuable insights about genomic information and nutritional regulation of TGF-beta6 which will aid the further investigation of the S. aurata TGF-beta6 gene in association with muscle growth. The finding of a novel TGF-beta6 molecule, unique to fish, will contribute to the understanding of the evolution of the TGF-beta family of cytokines in vertebrates.

Modulation of bone morphogenetic protein signaling in vivo regulates systemic iron balance.

Systemic iron balance is regulated by hepcidin, a peptide hormone secreted by the liver. By decreasing cell surface expression of the iron exporter ferroportin, hepcidin decreases iron absorption from the intestine and iron release from reticuloendothelial stores. Hepcidin excess has been implicated in the pathogenesis of anemia of chronic disease, while hepcidin deficiency has a key role in the pathogenesis of the iron overload disorder hemochromatosis. We have recently shown that hemojuvelin is a coreceptor for bone morphogenetic protein (BMP) signaling and that BMP signaling positively regulates hepcidin expression in liver cells in vitro. Here we show that BMP-2 administration increases hepcidin expression and decreases serum iron levels in vivo. We also show that soluble hemojuvelin (HJV.Fc) selectively inhibits BMP induction of hepcidin expression in vitro and that administration of HJV.Fc decreases hepcidin expression, increases ferroportin expression, mobilizes splenic iron stores, and increases serum iron levels in vivo. These data support a role for modulators of the BMP signaling pathway in treating diseases of iron overload and anemia of chronic disease.

TGF-beta signaling proteins and the Protein Ontology.

BACKGROUND: The Protein Ontology (PRO) is designed as a formal and principled Open Biomedical Ontologies (OBO) Foundry ontology for proteins. The components of PRO extend from a classification of proteins on the basis of evolutionary relationships at the homeomorphic level to the representation of the multiple protein forms of a gene, including those resulting from alternative splicing, cleavage and/or post-translational modifications. Focusing specifically on the TGF-beta signaling proteins, we describe the building, curation, usage and dissemination of PRO. RESULTS: PRO is manually curated on the basis of PrePRO, an automatically generated file with content derived from standard protein data sources. Manual curation ensures that the treatment of the protein classes and the internal and external relationships conform to the PRO framework. The current release of PRO is based upon experimental data from mouse and human proteins wherein equivalent protein forms are represented by single terms. In addition to the PRO ontology, the annotation of PRO terms is released as a separate PRO association file, which contains, for each given PRO term, an annotation from the experimentally characterized sub-types as well as the corresponding database identifiers and sequence coordinates. The annotations are added in the form of relationship to other ontologies. Whenever possible, equivalent forms in other species are listed to facilitate cross-species comparison. Splice and allelic variants, gene fusion products and modified protein forms are all represented as entities in the ontology. Therefore, PRO provides for the representation of protein entities and a resource for describing the associated data. This makes PRO useful both for proteomics studies where isoforms and modified forms must be differentiated, and for studies of biological pathways, where representations need to take account of the different ways in which the cascade of events may depend on specific protein modifications. CONCLUSION: PRO provides a framework for the formal representation of protein classes and protein forms in the OBO Foundry. It is designed to enable data retrieval and integration and machine reasoning at the molecular level of proteins, thereby facilitating cross-species comparisons, pathway analysis, disease modeling and the generation of new hypotheses.

Distinct and cooperative roles of mammalian Vg1 homologs GDF1 and GDF3 during early embryonic development.

Vg1, a member of the TGF-beta superfamily of ligands, has been implicated in the induction of mesoderm, formation of primitive streak, and left-right patterning in Xenopus and chick embryos. In mice, GDF1 and GDF3 - two TGF-beta superfamily ligands that share high sequence identity with Vg1 - have been shown to independently mimic distinct aspects of Vg1's functions. However, the extent to which the developmental processes controlled by GDF1 and GDF3 and the underlying signaling mechanisms are evolutionarily conserved remains unclear. Here we show that phylogenetic and genomic analyses indicate that Gdf1 is the true Vg1 ortholog in mammals. In addition, and similar to GDF1, we find that GDF3 signaling can be mediated by the type I receptor ALK4, type II receptors ActRIIA and ActRIIB, and the co-receptor Cripto to activate Smad-dependent reporter genes. When expressed in heterologous cells, the native forms of either GDF1 or GDF3 were incapable of inducing downstream signaling. This could be circumvented by using chimeric constructs carrying heterologous prodomains, or by co-expression with the Furin pro-protein convertase, indicating poor processing of the native GDF1 and GDF3 precursors. Unexpectedly, co-expression with Nodal - another TGF-beta superfamily ligand involved in mesoderm formation - could also expose the activities of native GDF1 and GDF3, suggesting a potentially novel mode of cooperation between these ligands. Functional complementarity between GDF1 and GDF3 during embryonic development was investigated by analyzing genetic interactions between their corresponding genes. This analysis showed that Gdf1(-/-);Gdf3(-/-) compound mutants are more severely affected than either Gdf1(-/-) or Gdf3(-/-) single mutants, with defects in the formation of anterior visceral endoderm and mesoderm that recapitulate Vg1 loss of function, suggesting that GDF1 and GDF3 together represent the functional mammalian homologs of Vg1.

Molecular characterization, tissue expression and sequence variability of the barramundi (Lates calcarifer) myostatin gene.

BACKGROUND: Myostatin (MSTN) is a member of the transforming growth factor-beta superfamily that negatively regulates growth of skeletal muscle tissue. The gene encoding for the MSTN peptide is a consolidate candidate for the enhancement of productivity in terrestrial livestock. This gene potentially represents an important target for growth improvement of cultured finfish. RESULTS: Here we report molecular characterization, tissue expression and sequence variability of the barramundi (Lates calcarifer) MSTN-1 gene. The barramundi MSTN-1 was encoded by three exons 379, 371 and 381 bp in length and translated into a 376-amino acid peptide. Intron 1 and 2 were 412 and 819 bp in length and presented typical GT...AG splicing sites. The upstream region contained cis-regulatory elements such as TATA-box and E-boxes. A first assessment of sequence variability suggested that higher mutation rates are found in the 5' flanking region with several SNP's present in this species. A putative micro RNA target site has also been observed in the 3'UTR (untranslated region) and is highly conserved across teleost fish. The deduced amino acid sequence was conserved across vertebrates and exhibited characteristic conserved putative functional residues including a cleavage motif of proteolysis (RXXR), nine cysteines and two glycosilation sites. A qualitative analysis of the barramundi MSTN-1 expression pattern revealed that, in adult fish, transcripts are differentially expressed in various tissues other than skeletal muscles including gill, heart, kidney, intestine, liver, spleen, eye, gonad and brain. CONCLUSION: Our findings provide valuable insights such as sequence variation and genomic information which will aid the further investigation of the barramundi MSTN-1 gene in association with growth. The finding for the first time in finfish MSTN of a miRNA target site in the 3'UTR provides an opportunity for the identification of regulatory mutations on the expression of this gene.

TGF­ß signaling: A complex role in tumorigenesis (Review).

Tumor progression can be affected by various cellular components of tumor cells and/or by tumor microenvironmental factors. The tumor microenvironment comprises a variety of nonmalignant stromal cells and inflammatory cytokines, which are pivotal in tumor promotion and progression. The transforming growth factor­ß (TGF­ß) ligands (TGF­ß1, 2 and 3) are secreted inflammatory cytokines, which are known to be involved in various aspects of tumor development through two transmembrane serine­threonine kinase receptors, TGFßR1 and TGFßR2. TGF­ß promotes or inhibits tumorigenesis depending on the concurrent gene mutations and tissue microenvironment present through the small mothers against decapentaplegic (Smad) and non­Smad pathways. This review aims to provide a comprehensive overview of the role of the TGF­ß pathway in tumor initiation and progression.

Intracellular mediators of transforming growth factor beta superfamily signaling localize to endosomes in chicken embryo and mouse lenses in vivo.

BACKGROUND: Endocytosis is a key regulator of growth factor signaling pathways. Recent studies showed that the localization to endosomes of intracellular mediators of growth factor signaling may be required for their function. Although there is substantial evidence linking endocytosis and growth factor signaling in cultured cells, there has been little study of the endosomal localization of signaling components in intact tissues or organs. RESULTS: Proteins that are downstream of the transforming growth factor-beta superfamily signaling pathway were found on endosomes in chicken embryo and postnatal mouse lenses, which depend on signaling by members of the TGFbeta superfamily for their normal development. Phosphorylated Smad1 (pSmad1), pSmad2, Smad4, Smad7, the transcriptional repressors c-Ski and TGIF and the adapter molecules Smad anchor for receptor activation (SARA) and C184M, localized to EEA-1- and Rab5-positive vesicles in chicken embryo and/or postnatal mouse lenses. pSmad1 and pSmad2 also localized to Rab7-positive late endosomes. Smad7 was found associated with endosomes, but not caveolae. Bmpr1a conditional knock-out lenses showed decreased nuclear and endosomal localization of pSmad1. Many of the effectors in this pathway were distributed differently in vivo from their reported distribution in cultured cells. CONCLUSION: Based on the findings reported here and data from other signaling systems, we suggest that the localization of activated intracellular mediators of the transforming growth factor-beta superfamily to endosomes is important for the regulation of growth factor signaling.

Signal processing in the TGF-beta superfamily ligand-receptor network.

The TGF-beta pathway plays a central role in tissue homeostasis and morphogenesis. It transduces a variety of extracellular signals into intracellular transcriptional responses that control a plethora of cellular processes, including cell growth, apoptosis, and differentiation. We use computational modeling to show that coupling of signaling with receptor trafficking results in a highly versatile signal-processing unit, able to sense by itself absolute levels of ligand, temporal changes in ligand concentration, and ratios of multiple ligands. This coupling controls whether the response of the receptor module is transient or permanent and whether or not different signaling channels behave independently of each other. Our computational approach unifies seemingly disparate experimental observations and suggests specific changes in receptor trafficking patterns that can lead to phenotypes that favor tumor progression.

Soluble osteogenic molecular signals and the induction of bone formation.

The induction of bone formation starts by erecting scaffolds of smart biomimetic matrices acting as insoluble signals affecting the release of soluble osteogenic molecular signals. The cascade of bone differentiation by induction develops as a mosaic structure singly initiated by the osteogenic proteins of the transforming growth factor-beta (TGF-beta) supergene family. The osteogenic signals when combined with an insoluble signal or substratum initiate de novo bone formation by induction and are deployed singly, synergistically and synchronously to sculpt the architecture of the mineralized bone/bone marrow organ. The osteogenic proteins of the TGF-beta superfamily are the common molecular initiators deployed for embryonic development and the induction of bone in postnatal osteogenesis, whereby molecules exploited in embryonic development are re-deployed in postnatal tissue morphogenesis as a recapitulation of embryonic development. The pleiotropy of the osteogenic proteins of the TGF-beta superfamily is highlighted by the apparent redundancy of molecular signals initiating bone formation by induction including the TGF-beta isoforms per se, powerful inducers of endochondral bone but in the primate only. Bone induction by the TGF-beta isoforms in the primate is site and tissue specific with substantial endochondral bone induction in heterotopic sites but with absent osteoinductivity in orthotopic calvarial sites on day 30 and only limited osteogenesis pericranially on day 90. Ebaf/Lefty-A, a novel member of the TGF-beta superfamily, induces chondrogenesis in calvarial defects of Papio ursinus and bone regeneration across the defect on day 30 and 90, respectively. The strikingly pleiotropic effects of the bone morphogenetic and osteogenic proteins (BMPs/OPs) spring from amino acid sequence variations in the carboxy-terminal domain and in the transduction of distinct signalling pathways by individual Smad proteins after transmembrane serine/threonine kinase complexes of type I and II receptors. Predictable bone regeneration in clinical contexts requires information concerning the expression and cross regulation of gene products of the TGF-beta superfamily. OP-1, BMP-3, TGF-beta1 and type IV collagen mRNAs expression correlates to the morphological induction and maintenance of engineered ossicles by the hOP-1 osteogenic devices in the non-human primate P. ursinus. Amino-acid sequence variations amongst BMPs/OPs in the carboxy terminal domain confer the structure/activity profile responsible for the pleiotropic activity that controls tissue induction and morphogenesis of a variety of tissues and organs by different BMPs/OPs which are helping to engineer skeletal tissue regeneration in molecular terms.

Inhibitors of the TGF-beta superfamily and their clinical applications.

The transforming growth factor-beta (TGF-beta) superfamily includes TGF-betas, activin, myostatin and bone morphogenetic proteins. Misregulation of the activity of TGF-beta family members is involved in pathogenesis of cancer, muscular dystrophy, obesity and bone and tooth remodeling. Natural inhibitors for the TGF-beta superfamily regulate fine-tuning of activity of TGF-beta family in vivo. In addition to natural inhibitors for the TGF-beta family, soluble forms of receptors for the TGF-beta family, blocking monoclonal antibodies and small chemical TGF-beta inhibitors have been developed. In this review, we summarize recent advances in our understanding of inhibitors for the TGF-beta superfamily and their medical applications.

Particular types of tumor cells have the capacity to convert transforming growth factor beta from a latent to an active form.

We investigated the capacities of various tumor types to generate an active versus latent form of transforming growth factor beta (TGF-beta) in its culture supernatants (SNs). Tumor cell lines were divided into three types depending on the form and magnitude of TGF-beta detected in their culture SNs: some (2 of 7 lines) generated mostly an active form (Type A); others (4 of 7) generated exclusively a latent form (Type B); and the remaining line (1 of 7) produced only marginal levels of active/latent TGF-beta (Type C). When Type A tumor cells were cultured at lower numbers, cultures failed to generate active TGF-beta. However, the addition of Type B tumor cell culture SNs containing only a latent form of TGF-beta resulted in the generation of the potent activity of active TGF-beta. This capacity was observed for another Type A tumor but not for other types (Type B and Type C). An active form of TGF-beta was detected in culture SNs of Type A tumor cells as early as 3-6 h after the addition of Type B tumor culture SNs. The emergence of an active form of TGF-beta was also observed in cultures of Type A tumor cells, the protein synthesis of which was almost completely inhibited by pretreatment with cycloheximide. Moreover, the Type B tumor SN used for the induction of active TGF-beta activity was found to contain latent TGF-beta with an apparent molecular weight of about 200,000. Type A tumor cells were also capable of generating active TGF-beta by the addition of recombinant TGF-beta of latent form with a small molecular weight (about 60,000), although the generation of active TGF-beta was much weaker after the addition of small latent TGF-beta than after the addition of large latent TGF-beta. Taken collectively, these results indicate that particular types of tumor cells have the capacity to generate an active form of TGF-beta and that such capacity can be attributed to their potential to convert TGF-beta from a latent (mainly large type) to an active form.

Crystal structure of human bone morphogenetic protein-2 at 2.7 A resolution.

Homodimeric bone morphogenetic protein-2 (BMP-2) is a member of the transforming growth factor beta (TGF-beta) superfamily that induces bone formation and regeneration, and determines important steps during early stages of embryonic development in vertebrates and non-vertebrates. BMP-2 can interact with two types of receptor chains, as well as with proteins of the extracellular matrix and several regulatory proteins. We report here the crystal structure of human BMP-2 determined by molecular replacement and refined to an R-value of 24.2 % at 2.7 A resolution. A common scaffold of BMP-2, BMP-7 and the TGF-betas, i.e. the cystine-knot motif and two finger-like double-stranded beta-sheets, can be superimposed with r. m.s. deviations of around 1 A. In contrast to the TGF-betas, the structure of BMP-2 shows differences in the flexibility of the N terminus and the orientation of the central alpha-helix as well as two external loops at the fingertips with respect to the scaffold. This is also known from the BMP-7 model. Small secondary structure elements in the loop regions of BMP-2 and BMP-7 seem to be specific for the respective BMP-subgroup. Two identical helix-finger clefts and two distinct cavities located around the central 2-fold axis of the dimer show characteristic shapes, polarity and surface charges. The possible function of these specific features in the interaction of BMP-2 with its binding partners is discussed.

Differential expression of TGF-beta 1, 2 and 3 isotypes in Alzheimer's disease: a comparative immunohistochemical study with cerebral infarction, aged human and mouse control brains.

Based upon the hypothesis that growth regulatory and inflammatory mechanisms participate in the pathogenesis of Alzheimer's disease, we studied cases of Alzheimer's disease for immunoreactivity to each of the three mammalian transforming growth factor beta (TGF-beta) isotypes: TGF-beta 1, TGF-beta 2, TGF-beta 3. Results were compared with those seen in control brains and in a destructive pathological process, subacute infarction. In the cases of Alzheimer's disease, TGF-beta 1 immunoreactivity was limited to neuritic profiles within senile plaques. Neuronal neurofibrillary tangles, plaque neurites, microglia, astrocytes and macrophages expressed TGF-beta 2 immunoreactivity. TGF-beta 3 produced strikingly selective staining of Hirano bodies. In contrast, in cases with infarction, reactive astrocytes and macrophages were positive with all three antibodies. Ramified microglia labeled selectively, as in the Alzheimer brains, with the TGF-beta 2 antibody. Subtle generalized astrocyte and microglial immunoreactivity for TGF-beta 2 was seen in pathological and control brains. The localization of TGF-beta isotypes to the lesions of Alzheimer's disease supports the hypothesis that these cytokines may influence lesion expression. Their presence in reactive cells associated with cerebral infarction suggest that they may play a broader role in the pathogenesis of CNS disease.

Human uterine tissue throughout the menstrual cycle expresses transforming growth factor-beta 1 (TGF beta 1), TGF beta 2, TGF beta 3, and TGF beta type II receptor messenger ribonucleic acid and protein and contains [125I]TGF beta 1-binding sites.

The use of isoform-specific transforming growth factor-beta (TGF beta) primers, 35S-labeled 40-mer oligonucleotide probes and polyclonal antibodies, reverse transcription-polymerase chain reaction, in situ hybridization, and immunohistochemical observations has revealed that human uterine tissue at various reproductive stages expresses TGF beta s and TGF beta type II receptor messenger RNAs (mRNAs) and proteins. The reverse transcription-polymerase chain reaction revealed the predicted 443-, 310-, 524-, and 431-basepair fragments for TGF beta 1, TGF beta 2, TGF beta 3, and TGF beta type II receptor, respectively, in both endometrial and myometrial tissues, which were further verified by restriction enzyme analysis. In situ hybridization and immunohistochemical observations indicated that all uterine cell types express TGF beta s mRNAs and proteins. In the functionalis region, endometrial luminal and glandular epithelial cells are the primary cell types expressing TGF beta s mRNAs and proteins, with lesser expression in stromal cells, whereas in the basalis region, they are equally expressed in both cell types. In myometrium, TGF beta mRNA and protein expression in smooth muscle cells occurs at a substantially lower level than in endometrial tissue. In endometrial tissue, the highest level of TGF beta mRNA and protein expression appeared in the late proliferative and early to midsecretory phases of the menstrual cycle, with a considerable reduction during the late secretory and postmenopausal periods. The pattern and cellular distribution of TGF beta type II receptor protein were similar to those seen with TGF beta isoforms in both endometrial and myometrial tissues. Quantitative autoradiography (net grain density per 100 microns 2) of specific binding of [125I]TGF beta 1 for different uterine cell types indicated that the stromal cells contain a higher grain density than other uterine cell types (P < 0.05), without a significantly different density in the proliferative, compared with the secretory, phase of the menstrual cycle. These data suggest that TGF beta s acting through their specific receptors may play an important role in a variety of uterine functions in an autocrine/paracrine manner, and ovarian steroids may also regulate their expression in endometrial tissue.

Transforming growth factor-beta-related proteins: an ancestral and widespread superfamily of cytokines in metazoans.

Members of the transforming growth factor beta (TGF-beta) superfamily of cell signalling polypeptides have attracted much attention because of their ability, from nematodes to mammals, to control cellular functions that in turn, regulate embryo development and tissue homeostasis. On the basis of structure similarities, the TGF-beta members (ligands, receptors and Smads) are subdivided into TGF-beta sensu stricto, bone morphogenetic proteins (BMP) and activins. Although BMP is the best characterized pathway in metazoans, recent findings in molluscs and non-bilateria as well as the analysis of nematode and arthropod genomes, demonstrate the early origin of these distinct subfamilies of ligands, receptors and Smads. This report analyses the large diversity of ligands, receptors and Smads in metazoans from cnidarians and molluscs to mammals. The contribution of new data, mainly from the lophochotrozoan Crassostrea gigas and other organisms on the fringe of the 'branded model organisms', will help us to demonstrate that TGF-betas are probably the most ancestral active cytokines characterized at the molecular level in both Protostome and Deuterostome lineages.

Regulation of the levels of three transforming growth factor beta mRNAs by estrogen and their effects on the proliferation of human breast cancer cells.

Transforming growth factor (TGF) beta is a potent regulator of cell proliferation and may play a role in breast cancer cell growth. We have evaluated the regulation of TGF beta 1, TGF beta 2, and TGF beta 3 mRNAs by 17 beta-estradiol (E2) and 4-hydroxytamoxifen (MOH) in estrogen receptor-positive (ER(+)) MCF-7 and estrogen receptor-negative (ER(-)) MDA-MB-231 human breast cancer cells. We also determined the effect of TGF beta 1, TGF beta 2, and TGF beta 3 on the proliferation of these cells. Cells were deprived of estrogen before the addition of hormones, and mRNA was measured by Northern blot analysis. We found that MCF-7 cells expressed mRNAs of all three TGF beta species. Treatment of MCF-7 cells with 10(-10) M E2 for 7 days resulted in a dramatic decrease in the TGF beta 2 and TGF beta 3 mRNA levels, but not in the TGF beta 1 mRNA level. MOH was found to block these effects. In addition, the regulation of TGF beta 2 and beta 3 gene expression occurs at both transcriptional and post-transcriptional levels. There is an inverse correlation between E2-induced growth and levels of TGF beta 2 and TGF beta 3 mRNA. In contrast to MCF-7 cells, MDA-MB-231 cells expressed TGF beta 1 and TGF beta 2 mRNAs but TGF beta 3 mRNA was not detected, and the TGF beta 1 and TGF beta 2 mRNAs were not regulated by estrogens or antiestrogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential localization of TGF-beta-precursor isotypes in normal human skin.

Transforming growth factor-beta (TGF-beta) can act as a multi-functional regulator of both cell growth and differentiation. Three isotypes of TGF-beta s namely TGF-beta 1, TGF-beta 2 and TGF-beta 3, have been found in human tissues. Up to now, little is known about the distribution patterns of the TGF-beta isotypes in human skin. Using the TGF-beta-precursor (latency-associated peptides) specific antibodies to confirm the specificity, we studied the immunohistochemical distribution of TGF-beta 1-3 in human skin. TGF-beta 2 was found mainly in the intercellular space of all the layers of the epidermis as well as in the cytoplasm with a weak staining. In contrast, TGF-beta 3 was present in the subepidermal area of the dermis. TGF-beta 1 was observed obviously in neither epidermis nor dermis. These results showed the differential localization of TGF-beta isotypes in human skin, suggesting that the TGF-beta 2 and TGF-beta 3 may regulate the human skin function in an epithelial autocrine or mesenchymal-epithelial interaction manner.

Differential localization of TGF-beta-precursor isotypes in psoriatic human skin.

Transforming growth factor-beta (TGF-beta) can act as a multi-functional regulator of both cell growth and differentiation. Three isoforms of TGF-betas, namely TGF-beta 1 TGF-beta 2 and TGF-beta 3, have been identified in human tissues. Previously we reported the expression of TGF-beta isoforms in normal human skin. However little is known about the role of TGF-beta isoforms in the pathogenesis of psoriasis. Using the TGF-beta precursor-specific antibodies to strengthen the specificity, we studied the immunohistochemical distribution of TGF-betas 1-3 in psoriatic skin. TGF-beta 2, which was found in the intercellular space of all the layers of the epidermis in normal human skin, was decreased in the psoriatic epidermis. The intensity of immunoreactivity has the tendency to decrease in the lower epidermis rather than in the upper epidermis of the transitional lesion. In contrast, TGF-beta 3 was present in the subepidermal area of the psoriatic skin as in the normal human skin. TGF-beta 1 was observed in neither epidermis nor dermis in both normal and psoriatic skin. Since TGF-beta is a potent growth inhibitor for human keratinocytes, the decrease of TGF-beta 2 in the epidermis of psoriatic skin may contribute to epidermal hyperplasia, a hallmark of psoriasis.

Expression of TGF-beta 1, -beta 2 and -beta 3 in localized and systemic scleroderma.

Scleroderma is a generalized or localized disorder which leads to fibrosis of the affected organs. TGF-beta has been implicated as a causal agent in its pathogenesis. In mammals, TGF-beta comprises a family of three members, beta 1, beta 2 and beta 3. Since cutaneous wound healing is thought to result either in formation of a scar or in scar-free tissue regeneration, depending on the relative amounts of the beta 3 isoform, the expression of all three isoforms was studied in skin biopsies of patients with either localized or systemic scleroderma. mRNA for all three isoforms was detected in inflammatory skin areas of both disease forms, but never in sclerotic or healthy skin. Immunohistochemical analysis confirmed expression of beta1 and beta 2 proteins in inflammatory skin of patients, whereas beta 3 protein appeared to be present in the subepidermal area and also found throughout the dermis of patients and healthy dermis as well.