TGF-beta: problems and prospects

A new method for network bioinformatics identifies novel drug targets for mucinous ovarian carcinoma

Mucinous ovarian carcinoma (MOC) is a subtype of ovarian cancer that is distinct from all other ovarian cancer subtypes and currently has no targeted therapies. To identify novel therapeutic targets, we developed and applied a new method of differential network analysis comparing MOC to benign mucinous tumours (in the absence of a known normal tissue of origin). This method mapped the protein-protein network in MOC and then utilised structural bioinformatics to prioritise the proteins identified as upregulated in the MOC network for their likelihood of being successfully drugged. Using this protein-protein interaction modelling, we identified the strongest 5 candidates, CDK1, CDC20, PRC1, CCNA2 and TRIP13, as structurally tractable to therapeutic targeting by small molecules. siRNA knockdown of these candidates performed in MOC and control normal fibroblast cell lines identified CDK1, CCNA2, PRC1 and CDC20, as potential drug targets in MOC. Three targets (TRIP13, CDC20, CDK1) were validated using known small molecule inhibitors. Our findings demonstrate the utility of our pipeline for identifying new targets and highlight potential new therapeutic options for MOC patients.

Regulation of homeostasis and regeneration in the adult intestinal epithelium by the TGF-β superfamily

The delicate balance between the homeostatic maintenance and regenerative capacity of the intestine makes this a fascinating tissue of study. The intestinal epithelium undergoes continuous homeostatic renewal but is also exposed to a diverse array of stresses that can range from physiological processes such as digestion, to exposure to infectious agents, drugs, radiation therapy, and inflammatory stimuli. The intestinal epithelium has thus evolved to efficiently maintain and reinstate proper barrier function that is essential for intestinal integrity and function. Factors governing homeostatic epithelial turnover are well described, however, the dynamic regenerative mechanisms that occur following injury are the subject of intense ongoing investigations. The TGF-β superfamily is a key regulator of both homeostatic renewal and regenerative processes of the intestine. Here we review the roles of TGF-β and BMP on the adult intestinal epithelium during self-renewal and injury to provide a framework for understanding how this major family of morphogens can tip the scale between intestinal health and disease. This article is protected by copyright. All rights reserved.

MiR-543 Inhibits the Migration and Epithelial-To-Mesenchymal Transition of TGF-β-Treated Endometrial Stromal Cells via the MAPK and Wnt/β-Catenin Signaling Pathways

Intrauterine adhesion (IUA) is one of the most prevalent reproductive system diseases in females. MicroRNAs (miRNAs) are reported to be master regulators in a variety of diseases, including IUA, but the role of microRNA-543 (miR-543) in IUA remains to be elucidated. In this study, we observed that miR-543 was downregulated in transforming growth factor-beta (TGF-β)-treated endometrial stromal cells (ESCs). Functionally, we observed that miR-543 suppressed the migration, epithelial-to-mesenchymal transition (EMT), and inhibited expression of extracellular matrix (ECM) proteins in TGF-β-treated ESCs. Mechanistically, MAPK1 is targeted by miR-543 after prediction and screening. A luciferase reporter assay demonstrated that miR-543 complementarily binds with the 3' untranslated region of mitogen-activated protein kinase 1 (MAPK1), and western blot analysis indicated that miR-543 negatively regulates MAPK1 protein levels. In addition, results from rescue assays showed that miR-543 inhibits the migration and EMT of TGF-β-treated ESCs by targeting MAPK1. In addition, we observed that miR-543 inactivates the Wnt/β-catenin signaling pathway through inhibiting the phosphorylation of MAPK1 and β-catenin. Finally, we confirmed that miR-543 represses migration, EMT and inhibits levels of ECM proteins in TGF-β-treated ESCs by targeting the Wnt/β-catenin signaling pathway. Our results demonstrated that miR-543 suppresses migration and EMT of TGF-β-treated ESCs by targeting the MAPK and Wnt/β-catenin pathways.

TAK1: a potent tumour necrosis factor inhibitor for the treatment of inflammatory diseases

Aberrant tumour necrosis factor (TNF) signalling is a hallmark of many inflammatory diseases including rheumatoid arthritis (RA), irritable bowel disease and lupus. Maladaptive TNF signalling can lead to hyper active downstream nuclear factor (NF)-κβ signalling in turn amplifying a cell's inflammatory response and exacerbating disease. Within the TNF intracellular inflammatory signalling cascade, transforming growth factor-β-activated kinase 1 (TAK1) has been shown to play a critical role in mediating signal transduction and downstream NF-κβ activation. Owing to its role in TNF inflammatory signalling, TAK1 has become a potential therapeutic target for the treatment of inflammatory diseases such as RA. This review highlights the current development of targeting the TNF-TAK1 signalling axis as a novel therapeutic strategy for the treatment of inflammatory diseases.

Evolving Role of Immunotherapy in Recurrent Metastatic Head and Neck Cancer

Immunotherapy has revolutionized cancer treatment in the past 2 decades, mostly with immune checkpoint blockade approaches. In squamous cell carcinoma of the head and neck (SCCHN), the initial efficacy of immunotherapy was observed in patients with recurrent or metastatic (R/M) disease who received other prior systemic treatment. As monotherapy, anti-PD-1 therapies induce responses in 13% to 18% of patients. More recently, immunotherapy in combination with cytotoxic chemotherapy demonstrated greater safety and efficacy as first-line systemic treatment compared with chemotherapy alone. In R/M SCCHN, the most important benefit of immunotherapy is the significantly improved overall survival, especially in patients with PD-L1-positive tumors. As of 2019, immunotherapy can be used as first-line or subsequent treatment of R/M SCCHN. Many ongoing trials are evaluating immunotherapy combinations or novel immunotherapy strategies, aiming to improve response rate and overall survival. As new targets are identified and new approaches are leveraged, the role of immunotherapy in R/M SCCHN continues to evolve.

Mechanisms of action and historical facts on the use of intravenous immunoglobulins in systemic lupus erythematosus

The current existing therapies for severe cases of systemic lupus erythematosus (SLE) patients are still limited. Intravenous immunoglobulin (IVIGs), which are purified from the plasma of thousands of healthy human donors, have been profiled as efficacious and life-saving options for SLE patients refractory to conventional therapy. The specific mechanism of action by which IVIGs generate immunomodulation in SLE is not currently understood. In this manuscript, we reviewed some of the hypothesis that have been postulated to explain the IVIG effects, including those on T and B cell intracellular signalling and activation, as well as the interferon signalling pathways involved in the detection of nucleic acids and the defective removal of immune complexes and debris.

Transforming growth factor beta 1 increases collagen content, and stimulates procollagen I and tissue inhibitor of metalloproteinase-1 production of dental pulp cells: Role of MEK/ERK and activin receptor-like kinase-5/Smad signaling

BACKGROUND/PURPOSE

In order to clarify the role of transforming growth factor beta 1 (TGF-β1) in pulp repair/regeneration responses, we investigated the differential signaling pathways responsible for the effects of TGF-β1 on collagen turnover, matrix metalloproteinase-3 (MMP-3), and tissue inhibitor of metalloproteinase-1 (TIMP-1) production in human dental pulp cells.

METHODS

Pulp cells were exposed to TGF-β1 with/without pretreatment and coincubation by 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenyl mercapto)butadiene (U0126; a mitogen-activated protein kinase kinase [MEK]/extracellular signal-regulated kinase [ERK] inhibitor) and 4-(5-benzol[1,3]dioxol-5-yl-4-pyrldin-2-yl-1H- imidazol-2-yl)-benzamide hydrate (SB431542; an activin receptor-like kinase-5/Smad signaling inhibitor). Sircol collagen assay was used to measure cellular collagen content. Culture medium procollagen I, TIMP-1, and MMP-3 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

TGF-β1 increased the collagen content, procollagen I, and TIMP-1 production, but slightly decreased MMP-3 production of pulp cells. SB431542 and U0126 prevented the TGF-β1-induced increase of collagen content and TIMP-1 production of dental pulp cells.

CONCLUSION

These results indicate that TGF-β1 may be involved in the healing/regeneration processes of dental pulp in response to injury by stimulation of collagen and TIMP-1 production. These events are associated with activin receptor-like kinase-5/Smad2/3 and MEK/ERK signaling.

Laser-activated transforming growth factor-β1 induces human β-defensin 2: implications for laser therapies for periodontitis and peri-implantitis

BACKGROUND

There is increasing popularity of high-power lasers for surgical debridement and antimicrobial therapy in the management of peri-implantitis and periodontal therapy. Removal of the noxious foci would naturally promote tissue healing directly. However, there are also anecdotal reports of better healing around routine high-power laser procedures. The precise mechanisms mediating these effects remain to be fully elucidated. This work examines these low-dose laser bystander effects on oral human epithelial and fibroblasts, particularly focusing on the role of human β-defensin 2 (HBD-2 or DEFB4A), a potent factor capable of antimicrobial effects and promoting wound healing.

MATERIAL AND METHODS

Laser treatments were performed using a near-infrared laser (810 nm diode) at low doses. Normal human oral keratinocytes and fibroblast cells were used and HBD-2 mRNA and protein expression was assessed with real time polymerase chain reaction, western blotting and immunostaining. Role of transforming growth factor (TGF)-β1 signaling in this process was dissected using pathway-specific small molecule inhibitors.

RESULTS

We observed laser treatments robustly induced HBD-2 expression in an oral fibroblast cell line compared to a keratinocyte cell line. Low-dose laser treatments results in activation of the TGF-β1 pathway that mediated HBD-2 expression. The two arms of TGF-β1 signaling, Smad and non-Smad are involved in laser-mediated HBD-2 expression.

CONCLUSIONS

Laser-activated TGF-β1 signaling and induced expression of HBD-2, both of which are individually capable of promoting healing in tissues adjacent to high-power surgical laser applications. Moreover, the use of low-dose laser therapy itself can provide additional therapeutic benefits for effective clinical management of periodontal or peri-implant disease.

Role of ALK5/Smad2/3 and MEK1/ERK Signaling in Transforming Growth Factor Beta 1-modulated Growth, Collagen Turnover, and Differentiation of Stem Cells from Apical Papilla of Human Tooth

INTRODUCTION

Transforming growth factor β1 (TGF-β1) plays an important role in cell proliferation, matrix formation, and odontogenesis. This study investigated the effects of TGF-β1 on stem cells from apical papilla (SCAPs) and its signaling by MEK/ERK and Smad2.

METHODS

SCAPs were exposed to TGF-β1 with/without pretreatment and coincubation by SB431542 (an ALK5/Smad 2/3 inhibitor) or U0126 (a MEK/ERK inhibitor). Cell growth was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay or direct counting of viable cells. Collagen content was determined by using the Sircol collagen assay (Biocolor Ltd, Newtownabbey, Northern Ireland). Cell differentiation was evaluated by measuring alkaline phosphatase (ALP) activity. Smad2 and ERK1/2 phosphorylation was analyzed by Western blotting or PathScan phospho-enzyme-linked immunosorbent assay (Cell Signaling Technology Inc, Danvers, MA).

RESULTS

TGF-β1 stimulated the growth and collagen content of cultured SCAPs. TGF-β1 stimulated ERK1/2 and Smad2 phosphorylation within 60 minutes of exposure. Pretreatment by U0126 and SB431542 effectively prevented the TGF-β1-induced cell growth and collagen content in SCAPs. TGF-β1 stimulated ALP activity at lower concentrations (0.1-1 ng/mL) but down-regulated ALP at higher concentrations (>5 ng/mL). U0126 prevented 0.5 ng/mL TGF-β1-induced ALP activity but showed little effect on 10 ng/mL TGF-β1-induced decline of ALP in SCAPs. Interestingly, SB431542 attenuated both the stimulatory and inhibitory effects on ALP by TGF-β1.

CONCLUSIONS

TGF-β1 may affect the proliferation, collagen turnover, and differentiation of SCAPs via differential activation of ALK5/Smad2 and MEK/ERK signaling. These results highlight the future use of TGF-β1 and SCAP for engineering of pulpal regeneration and apexogenesis.

Delineating the prime mover action of progesterone for endometrial receptivity in primates

Progesterone is essential for endometrial receptivity in primates. It is now evident that embryo-derived signal influences implantation stage endometrium under progesterone dominance, and collectively results in endometrial receptivity to implanting blastocyst. Previously, a few studies were performed using global gene profiling based on microarray technology to identify changes in gene expression between early luteal phase and mid luteal phase endometrium, however, the issue of combinatorial regulation by progesterone-dependent regulation and by embryo-derived signal on transcripts profiles during endometrial differentiation toward receptivity for blastocyst implantation in primates has not been addressed. the present review summarizes a few issues, specifically that of transforming growth factor β-tumour necrosis factor α (TGFβ-TNFα) pathways and signal transducer and activator of transcription (STAT) signalling system related to luteal phase progesterone action on endometrial receptivity in terms of its transcriptomic expression using a potent antiprogestin (mifepristone) in conception cycles of the rhesus monkey as a non-human primate model.

Identification of a Novel Compound That Suppresses Breast Cancer Invasiveness by Inhibiting Transforming Growth Factor-β Signaling via Estrogen Receptor α

Breast cancer is the most frequently diagnosed cancer and the leading cause of death by cancer among females worldwide. An overwhelming majority of these deaths is because of metastasis. Estrogen stimulates and promotes growth of breast tumors, whereas transforming growth factor-beta (TGF-β) signaling promotes invasion and metastasis. We previously reported that estrogen and estrogen receptor alpha (ERα) suppressed breast cancer metastasis by inhibiting TGF-β signaling, whereas antiestrogens that suppress breast cancer growth, such as the selective ER modulator tamoxifen (TAM) or the pure antiestrogen fulvestrant (ICI 182,780), cannot suppress TGF-β signaling or breast cancer invasiveness. Therefore, we predicted that a compound that inhibits TGF-β signaling but does not facilitate ERα signaling would be ideal for suppressing breast cancer invasiveness and growth. In the present study, we identified an ideal candidate compound, N-23. Like estrogen, N-23 strongly decreased expression of TGF-β/Smad target gene plasminogen activator inhibitor-1 (PAI-1), but it did not increase the expression of ERα target gene pS2. While estrogen decreased the levels of phosphorylated Smad2 and Smad3, N-23 had no effect. In addition, TGF-β-dependent recruitment of Smad3 to the PAI-1 gene promoter was inhibited in the presence of estrogen or N-23. We also investigated the effects of N-23 on proliferation, migration, and invasion of breast cancer cells. In contrast to estrogen, N-23 inhibited the cellular proliferation of breast cancer cells. Moreover, we showed that N-23 suppressed the migration and invasion of breast cancer cells to the same extent as by estrogen. Taken together, our findings indicate that N-23 may be a candidate compound that is effective in inhibiting breast cancer progression.

A nonclassical vitamin D receptor pathway suppresses renal fibrosis

The TGF-β superfamily comprises pleiotropic cytokines that regulate SMAD and non-SMAD signaling. TGF-β-SMAD signal transduction is known to be involved in tissue fibrosis, including renal fibrosis. Here, we found that 1,25-dihydroxyvitamin D3-bound [1,25(OH)2D3-bound] vitamin D receptor (VDR) specifically inhibits TGF-β-SMAD signal transduction through direct interaction with SMAD3. In mouse models of tissue fibrosis, 1,25(OH)2D3 treatment prevented renal fibrosis through the suppression of TGF-β-SMAD signal transduction. Based on the structure of the VDR-ligand complex, we generated 2 synthetic ligands. These ligands selectively inhibited TGF-β-SMAD signal transduction without activating VDR-mediated transcription and significantly attenuated renal fibrosis in mice. These results indicate that 1,25(OH)2D3-dependent suppression of TGF-β-SMAD signal transduction is independent of VDR-mediated transcriptional activity. In addition, these ligands did not cause hypercalcemia resulting from stimulation of the transcriptional activity of the VDR. Thus, our study provides a new strategy for generating chemical compounds that specifically inhibit TGF-β-SMAD signal transduction. Since TGF-β-SMAD signal transduction is reportedly involved in several disorders, our results will aid in the development of new drugs that do not cause detectable adverse effects, such as hypercalcemia.

Identification of a Novel Link between the Protein Kinase NDR1 and TGFβ Signaling in Epithelial Cells

Transforming growth factor-beta (TGFβ) is a secreted polypeptide that plays essential roles in cellular development and homeostasis. Although mechanisms of TGFβ-induced responses have been characterized, our understanding of TGFβ signaling remains incomplete. Here, we uncover a novel function for the protein kinase NDR1 (nuclear Dbf2-related 1) in TGFβ responses. Using an immunopurification approach, we find that NDR1 associates with SnoN, a key component of TGFβ signaling. Knockdown of NDR1 by RNA interference promotes the ability of TGFβ to induce transcription and cell cycle arrest in NMuMG mammary epithelial cells. Conversely, expression of NDR1 represses TGFβ-induced transcription and inhibits the ability of TGFβ to induce cell cycle arrest in NMuMG cells. Mechanistically, we find that NDR1 acts in a kinase-dependent manner to suppress the ability of TGFβ to induce the phosphorylation and consequent nuclear accumulation of Smad2, which is critical for TGFβ-induced transcription and responses. Strikingly, we also find that TGFβ reciprocally regulates NDR1, whereby TGFβ triggers the degradation of NDR1 protein. Collectively, our findings define a novel and intimate link between the protein kinase NDR1 and TGFβ signaling. NDR1 suppresses TGFβ-induced transcription and cell cycle arrest, and counteracting NDR1's negative regulation, TGFβ signaling induces the downregulation of NDR1 protein. These findings advance our understanding of TGFβ signaling, with important implications in development and tumorigenesis.

Antifibrotic effects of ω-3 fatty acids in the heart: one possible treatment for diastolic heart failure

Half of heart failure patients have diastolic heart failure, which has no effective treatments. Several studies indicate a role for ω-3 polyunsaturated fatty acids (PUFAs) in heart failure. Recent studies suggest that ω-3 PUFAs inhibit cardiac fibrosis and attenuate diastolic dysfunction. This opens up possible new avenues for treatment of diastolic heart failure. In this review, we focus on the antifibrotic effects of ω-3 PUFAs in heart and the underlying cellular and molecular mechanisms.

Lack of Smad3 signaling leads to impaired skeletal muscle regeneration

Smad3 is a key intracellular signaling mediator for both transforming growth factor-β and myostatin, two major regulators of skeletal muscle growth. Previous published work has revealed pronounced muscle atrophy together with impaired satellite cell functionality in Smad3-null muscles. In the present study, we have further validated a role for Smad3 signaling in skeletal muscle regeneration. Here, we show that Smad3-null mice had incomplete recovery of muscle weight and myofiber size after muscle injury. Histological/immunohistochemical analysis suggested impaired inflammatory response and reduced number of activated myoblasts during the early stages of muscle regeneration in the tibialis anterior muscle of Smad3-null mice. Nascent myofibers formed after muscle injury were also reduced in number. Moreover, Smad3-null regenerated muscle had decreased oxidative enzyme activity and impaired mitochondrial biogenesis, evident by the downregulation of the gene encoding mitochondrial transcription factor A, a master regulator of mitochondrial biogenesis. Consistent with known Smad3 function, reduced fibrotic tissue formation was also seen in regenerated Smad3-null muscle. In conclusion, Smad3 deficiency leads to impaired muscle regeneration, which underscores an essential role of Smad3 in postnatal myogenesis. Given the negative role of myostatin during muscle regeneration, the increased expression of myostatin observed in Smad3-null muscle may contribute to the regeneration defects.

Mutations in protein-binding hot-spots on the hub protein Smad3 differentially affect its protein interactions and Smad3-regulated gene expression

Background

Hub proteins are connected through binding interactions to many other proteins. Smad3, a mediator of signal transduction induced by transforming growth factor beta (TGF-β), serves as a hub protein for over 50 protein-protein interactions. Different cellular responses mediated by Smad3 are the product of cell-type and context dependent Smad3-nucleated protein complexes acting in concert. Our hypothesis is that perturbation of this spectrum of protein complexes by mutation of single protein-binding hot-spots on Smad3 will have distinct consequences on Smad3-mediated responses.

Methodology/Principal Findings

We mutated 28 amino acids on the surface of the Smad3 MH2 domain and identified 22 Smad3 variants with reduced binding to subsets of 17 Smad3-binding proteins including Smad4, SARA, Ski, Smurf2 and SIP1. Mutations defective in binding to Smad4, e.g., D408H, or defective in nucleocytoplasmic shuttling, e.g., W406A, were compromised in modulating the expression levels of a Smad3-dependent reporter gene or six endogenous Smad3-responsive genes: Mmp9, IL11, Tnfaip6, Fermt1, Olfm2 and Wnt11. However, the Smad3 mutants Y226A, Y297A, W326A, K341A, and E267A had distinct differences on TGF-β signaling. For example, K341A and Y226A both reduced the Smad3-mediated activation of the reporter gene by ∼50% but K341A only reduced the TGF-β inducibilty of Olfm2 in contrast to Y226A which reduced the TGF-β inducibility of all six endogenous genes as severely as the W406A mutation. E267A had increased protein binding but reduced TGF-β inducibility because it caused higher basal levels of expression. Y297A had increased TGF-β inducibility because it caused lower Smad3-induced basal levels of gene expression.

Conclusions/Significance

Mutations in protein binding hot-spots on Smad3 reduced the binding to different subsets of interacting proteins and caused a range of quantitative changes in the expression of genes induced by Smad3. This approach should be useful for unraveling which Smad3 protein complexes are critical for specific biological responses.

Transforming growth factor Beta2 is required for valve remodeling during heart development

Although the function of transforming growth factor beta2 (TGFβ2) in epithelial mesenchymal transition (EMT) is well studied, its role in valve remodeling remains to be fully explored. Here, we used histological, morphometric, immunohistochemical and molecular approaches and showed that significant dysregulation of major extracellular matrix (ECM) components contributed to valve remodeling defects in Tgfb2(-/-) embryos. The data indicated that cushion mesenchymal cell differentiation was impaired in Tgfb2(-/-) embryos. Hyaluronan and cartilage link protein-1 (CRTL1) were increased in hyperplastic valves of Tgfb2(-/-) embryos, indicating increased expansion and diversification of cushion mesenchyme into the cartilage cell lineage during heart development. Finally, Western blot and immunohistochemistry analyses indicate that the activation of SMAD2/3 was decreased in Tgfb2(-/-) embryos during valve remodeling. Collectively, the data indicate that TGFβ2 promotes valve remodeling and differentiation by inducing matrix organization and suppressing cushion mesenchyme differentiation into cartilage cell lineage during heart development.

Estrogen and antiestrogens alter breast cancer invasiveness by modulating the transforming growth factor-β signaling pathway

In the later stages of breast cancer, estrogen receptor (ER)α-negative cancers typically have higher histological grades than ERα-positive cancers, and transforming growth factor (TGF)-β promotes invasion and metastasis. Our previous study indicated that ERα inhibited TGF-β signaling by inducing the degradation of Smad in an estrogen-dependent manner. In the present study, we report that the suppressive effects of ERα and estrogen on tumor progression are mediated by inhibiting TGF-β signaling. Furthermore, we investigated the effects of antiestrogens such as ICI182,780 (ICI) or tamoxifen (TAM) on TGF-β signaling and breast cancer invasiveness. The levels of total Smad and pSmad were reduced by estrogen, whereas ICI slightly increased them, and TAM had no effect. To investigate the effect of antiestrogens on breast cancer invasiveness, we generated highly migratory and invasive MCF-7-M5 cells. The migration and invasion of these cells were suppressed by the inhibitor of TGF-β receptor kinase, SB-505124, and estrogen. However, antiestrogens did not suppress the migration and invasion of these cells. In addition, we screened TGF-β target genes whose expression was reduced by estrogen treatment and identified four genes associated with breast cancer invasiveness and poor prognosis. The expression of these genes was not decreased by antiestrogens. These observations provide a new insight into estrogen function and the mechanisms underlying estrogen-mediated suppression of tumor progression.

Identification of retinoic acid in a high content screen for agents that overcome the anti-myogenic effect of TGF-beta-1

BACKGROUND

Transforming growth factor beta 1 (TGF-β1) is an inhibitor of muscle cell differentiation that is associated with fibrosis, poor regeneration and poor function in some diseases of muscle. When neutralizing antibodies to TGF-β1 or the angiotensin II inhibitor losartan were used to reduce TGF-β1 signaling, muscle morphology and function were restored in mouse models of Marfan Syndrome and muscular dystrophy. The goal of our studies was to identify additional agents that overcome the anti-myogenic effect of TGF-β1.

METHODOLOGY/PRINCIPAL FINDINGS

A high-content cell-based assay was developed in a 96-well plate format that detects the expression of myosin heavy chain (MHC) in C2C12 cells. The assay was used to quantify the dose-dependent responses of C2C12 cell differentiation to TGF-β1 and to the TGF-β1 Type 1 receptor kinase inhibitor, SB431542. Thirteen agents previously described as promoting C2C12 differentiation in the absence of TGF-β1 were screened in the presence of TGF-β1. Only all-trans retinoic acid and 9-cis retinoic acid allowed a maximal level of C2C12 cell differentiation in the presence of TGF-β1; the angiotensin-converting enzyme inhibitor captopril and 10 nM estrogen provided partial rescue. Vitamin D was a potent inhibitor of retinoic acid-induced myogenesis in the presence of TGF-β1. TGF-β1 inhibits myoblast differentiation through activation of Smad3; however, retinoic acid did not inhibit TGF-β1-induced activation of a Smad3-dependent reporter gene in C2C12 cells.

CONCLUSIONS/SIGNIFICANCE

Retinoic acid alleviated the anti-myogenic effect of TGF-β1 by a Smad3-independent mechanism. With regard to the goal of improving muscle regeneration and function in individuals with muscle disease, the identification of retinoic acid is intriguing in that some retinoids are already approved for human therapy. However, retinoids also have well-described adverse effects. The quantitative, high-content assay will be useful to screen for less-toxic retinoids or combinations of agents that promote myoblast differentiation in the presence of TGF-β1.

Estrogen inhibits transforming growth factor beta signaling by promoting Smad2/3 degradation

Estrogen is a growth factor that stimulates cell proliferation. The effects of estrogen are mediated through the estrogen receptors, ERalpha and ERbeta, which function as ligand-induced transcription factors and belong to the nuclear receptor superfamily. On the other hand, TGF-beta acts as a cell growth inhibitor, and its signaling is transduced by Smads. Although a number of studies have been made on the cross-talk between estrogen/ERalpha and TGF-beta/Smad signaling, whose molecular mechanisms remain to be determined. Here, we show that ERalpha inhibits TGF-beta signaling by decreasing Smad protein levels. ERalpha-mediated reductions in Smad levels did not require the DNA binding ability of ERalpha, implying that ERalpha opposes the effects of TGF-beta via a novel non-genomic mechanism. Our analysis revealed that ERalpha formed a protein complex with Smad and the ubiquitin ligase Smurf, and enhanced Smad ubiquitination and subsequent degradation in an estrogen-dependent manner. Our observations provide new insight into the molecular mechanisms governing the non-genomic functions of ERalpha.

ODEs model of foreign body reaction around peripheral nerve implanted electrode

The foreign body reaction that the neural tissue develops around an implanted electrode contributes to insulate the probe and enhances the electrical and mechanical mismatch. It is a complex interaction among cells and soluble mediators and the knowledge of this phenomenon can benefits of formal and analytical methods that characterize the mathematical models. This work offers a lumped component model, described by ordinary differential equations, that taking into account the main geometrical (size, shape, insertion angle) and chemical (coating surface) properties of the implant predict the thickness of the fibrotic capsule in a time frame when the reaction stabilizes. This tool allows to evaluate different hypothetical solutions for accounting the tissue-electrode mismatch.

Epithelial raft cultures for investigations of virus growth, pathogenesis and efficacy of antiviral agents

The organotypic epithelial raft cultures, originally developed to study keratinocytes differentiation, represent a novel approach to the study of viruses able to infect epithelial cells. Organotypic epithelial raft cultures accurately reproduce the process of epithelial differentiation in vitro and can be prepared from normal keratinocytes, explanted epithelial tissue, or established cell lines. This culture system permits cells to proliferate and fully differentiate at the air-liquid interface on a dermal-equivalent support. Normal primary human keratinocytes (PHKs) stratify and fully differentiate in a manner similar to the normal squamous epithelial tissues, while transformed cell lines exhibit dysplastic morphologies similar to the (pre)neoplastic lesions seen in vivo. This three-dimensional (3D) culture system provides an essential tool for investigations of virus growth, virus-host cell interactions, for the genetic analysis of viral proteins and regulatory sequences, and for the evaluation of antiviral agents. The 3D epithelial cultures have proven a breakthrough in the research on papillomaviruses, since their life cycle is strictly linked to the differentiation of the host epithelium. In the last years, several reports have shown the usefulness of the 3D epithelial cultures for the study of other viruses that target at least during a part of their life cycles epithelial cells. The 3D epithelial cultures allow the analysis of virus-host cell interactions in stratified epithelia that more closely resemble the in vivo situation. In this review we describe the advances on research on 3D epithelial cultures for the study of virus growth and pathogenesis of different families of viruses, including papilloma-, herpes-, pox-, adeno-, and parvoviruses.

Increased blood plasma concentrations of TGF-beta1 and TGF-beta2 after treatment with intravenous immunoglobulins in childhood autoimmune diseases

Transforming growth factor-beta (TGF-beta), a multifunctional, immunosuppressive cytokine, is shown to be present in substantial amounts in commercially available intravenous immunoglobulin (IVIG) preparations. To assess whether TGF-beta isoforms are changed in the plasma of paediatric patients with childhood autoimmune diseases after IVIG infusion, 17 patients who received over a period of 12 months overall 56 IVIG infusions (Endobulin) were enrolled in a study. High levels of TGF-beta1 (16.95 +/- 8.16 ng/ml) as well as TGF-beta2 (62.71 +/- 9.50 ng/ml) were detected in the used 56 IVIG probes. TGF-beta1 and TGF-beta2 plasma concentrations were measured prior and 120 min after IVIG infusions by specific TGF-beta ELISA. Interestingly, significant increased TGF-beta1 and TGF-beta2 plasma levels were found in patients after treatment with IVIG. This data suggest that a TGF-beta-mediated mechanism of action may accompany other molecular effects of IVIG therapy. The amount of the potent anti-inflammatory TGF-beta isoforms within the IVIG preparations may exert a differentiated view regarding the manifold indications of IVIG therapy.

Transforming growth factor-beta1 shows an incremental osteoinductive dose-response relationship

OBJECTIVE

To determine if there is a dose-response curve for TGF-beta1 in a rabbit calvarial defect model.

STUDY DESIGN

Controlled animal study using arms of increasing concentrations of TGF-beta1 to evaluate the osteoinductive potential of each arm.

METHODS

Sixteen skeletally mature New Zealand white rabbits were randomized into control and experimental arms. Incremental doses of TGF-beta1 delivered in an inactivated guanidine-extracted demineralized bone matrix (Gu-DBM) carrier were implanted into a critically sized calvarial defect. The animals were sacrificed at 4 weeks and histomorphometric analysis was then accomplished.

RESULTS

TGF-beta1 showed a dose-response relationship, with the higher doses chosen for this study causing more robust osteoinduction.

CONCLUSIONS

In this pilot dosing study, TGF-beta1 demonstrates increasing osteoinduction with increasing dose levels in this animal model.

The differentiation of human T(H)-17 cells requires transforming growth factor-beta and induction of the nuclear receptor RORgammat

T(H)-17 cells are interleukin 17 (IL-17)-secreting CD4+ T helper cells involved in autoimmune disease and mucosal immunity. In naive CD4+ T cells from mice, IL-17 is expressed in response to a combination of IL-6 or IL-21 and transforming growth factor-beta (TGF-beta) and requires induction of the nuclear receptor RORgammat. It has been suggested that the differentiation of human T(H)-17 cells is independent of TGF-beta and thus differs fundamentally from that in mice. We show here that TGF-beta, IL-1beta and IL-6, IL-21 or IL-23 in serum-free conditions were necessary and sufficient to induce IL-17 expression in naive human CD4+ T cells from cord blood. TGF-beta upregulated RORgammat expression but simultaneously inhibited its ability to induce IL-17 expression. Inflammatory cytokines relieved this inhibition and increased RORgammat-directed IL-17 expression. Other gene products detected in T(H)-17 cells after RORgammat induction included the chemokine receptor CCR6, the IL-23 receptor, IL-17F and IL-26. Our studies identify RORgammat as having a central function in the differentiation of human T(H)-17 cells from naive CD4+ T cells and suggest that similar cytokine pathways are involved in this process in mice and humans.

Tissue stretch decreases soluble TGF-beta1 and type-1 procollagen in mouse subcutaneous connective tissue: evidence from ex vivo and in vivo models

Transforming growth factor beta 1 (TGF-beta1) plays a key role in connective tissue remodeling, scarring, and fibrosis. The effects of mechanical forces on TGF-beta1 and collagen deposition are not well understood. We tested the hypothesis that brief (10 min) static tissue stretch attenuates TGF-beta1-mediated new collagen deposition in response to injury. We used two different models: (1) an ex vivo model in which excised mouse subcutaneous tissue (N = 44 animals) was kept in organ culture for 4 days and either stretched (20% strain for 10 min 1 day after excision) or not stretched; culture media was assayed by ELISA for TGF-beta1; (2) an in vivo model in which mice (N = 22 animals) underwent unilateral subcutaneous microsurgical injury on the back, then were randomized to stretch (20-30% strain for 10 min twice a day for 7 days) or no stretch; subcutaneous tissues of the back were immunohistochemically stained for Type-1 procollagen. In the ex vivo model, TGF-beta1 protein was lower in stretched versus non-stretched tissue (repeated measures ANOVA, P < 0.01). In the in vivo model, microinjury resulted in a significant increase in Type-1 procollagen in the absence of stretch (P < 0.001), but not in the presence of stretch (P = 0.21). Thus, brief tissue stretch attenuated the increase in both soluble TGF-beta1 (ex vivo) and Type-1 procollagen (in vivo) following tissue injury. These results have potential relevance to the mechanisms of treatments applying brief mechanical stretch to tissues (e.g., physical therapy, respiratory therapy, mechanical ventilation, massage, yoga, acupuncture).

Transforming growth factor (TGF)-beta1-induced human endometrial stromal cell decidualization through extracellular signal-regulated kinase and Smad activation in vitro: peroxisome proliferator-activated receptor gamma acts as a negative regulator of TGF-beta1

OBJECTIVE

To investigate the effect of transforming growth factor (TGF)-beta1 on the extracellular signal-regulated kinase (ERK) and Smad pathway and the role of peroxisome proliferator-activated receptor (PPAR)-gamma in cultured human endometrial stromal cells.

DESIGN

Experimental study.

SETTING

Infertility center of a tertiary university hospital. MATERIAL(S): Human endometrial tissues obtained by hysterectomy from patients with conditions other than endometrial diseases.

INTERVENTION(S)

Endometrial stromal cells were cultured under normal laboratory conditions. TGF-beta1, rosiglitazone (PPARgamma agonist), and PD98059 (ERK inhibitor) were added to endometrial stromal cell culture according to experimental purposes.

MAIN OUTCOME MEASURE(S)

Cell count, PRL expression, Smad and ERK phosphorylation, cyclooxygenase (COX)-2 expression, and prostaglandin E(2) (PGE(2)) release.

RESULT(S)

TGF-beta1 inhibited cellular proliferation and induced the expressions of COX-2, PGE(2), and PRL of cultured human endometrial stromal cells. These effects may be mediated by Smad and ERK phosphorylation. Treatment with rosiglitazone, a PPARgamma agonist, reversed the TGF-beta1 effect by antagonizing the activation of ERK and Smad that was induced by TGF-beta1.

CONCLUSION(S)

PPARgamma plays a negative role by directly acting on Smad and ERK phosphorylation in human endometrial cell decidualization that is induced by TGF-beta1 in vitro.

Transforming growth factor-beta 1 gene polymorphisms and expression in the blood of prostate cancer patients

The transforming growth factor beta 1 (TGF-beta1) is a multifunctional cytokine with several regulatory activities in tumor cells affecting growth, differentiation, and function. Alterations in gene expression, secretion, and regulation of TGF-beta1 may lead to a favorable environment for tumor development by angiogenesis stimulation and immune system suppression. We evaluated the influence of the TGFB1 polymorphisms by ARMS-PCR, Leu10Pro, and Arg25Pro, on prostate cancer (PCa) and benign prostatic hyperplasia (BPH). We assessed TGFB1 polymorphisms and their relation to mRNA levels (semi-quantitative RT-PCR) in blood samples as well as the implications in disease occurrence and progression. Peripheral blood samples from 175 patients were analyzed as to 92 BPH and 83 PCa. Samples obtained from 132 healthy males were used as negative controls. PCa patients with a Gleason score greater than 7 presented a higher frequency of the C allele (Leu10Pro). This allele was associated with a higher risk of developing PCa and BPH compared to the population (2.6 and 3.6 times higher, respectively). Patients with TGFB1 transcript levels equal to or more than 70% higher than control levels presented a 5.34 and 2.14-fold higher risk of having PCa and BPH, respectively, relative to the population. No association was detected between polymorphisms and mRNA levels. The C allele of the Leu10Pro polymorphism may predispose men to a more rapid cancer progression. Additionally, higher mRNA levels in the peripheral blood of PCa patients suggest that tumor cells may be disseminated in the circulation and could be used as a biomarker for extra-capsular invasion.

Inhibition of human neutrophil degranulation by transforming growth factor-beta1

Neutrophils enter tissues including the uterus and are found in the endometrium in increased numbers prior to menses. In this environment, they are exposed to transforming growth factor (TGF)-beta1 produced by endometrial stromal and epithelial cells. We observed that incubation of neutrophils in vitro with TGF-beta1 at 1 pg/ml significantly reduced their secretion of lactoferrin in response to lipopolysaccharide (LPS). This effect was achieved with as little as 15 min of pretreatment with TGF-beta1. Inhibition of lactoferrin release by TGF-beta1 was observed irrespective of whether neutrophils were stimulated by ligands for Toll-like receptor (TLR)-2, TLR-4 or FPR, the G protein-coupled receptor for formylated peptides. Inhibition by TGF-beta1 was negated by SB-431542, a small molecule inhibitor that specifically blocks the kinase activity of the type I TGF-beta receptor (ALK5) In contrast to lactoferrin release, another important neutrophil function, interleukin (IL)-8 driven chemotaxis, was not affected by TGF-beta1 at 1 pg/ml or 100 pg/ml. We conclude that in tissues of the female reproductive tract, TGF-beta1 inhibition of neutrophil degranulation may prevent these cells from initiating an inflammatory response or releasing degradative enzymes that could potentially damage the oocyte or fetus.

Dynamics of expression of growth differentiation factor 15 in normal and PIN development in the mouse

Growth differentiation factor (GDF15) is a distant member of the transforming growth factor-beta superfamily, a diverse group of structurally related proteins that exert multiple effects on cell fate such as on cell growth and differentiation but little is known about GDF15 in these processes. Previously we observed the mature GDF15 to be associated with human prostate carcinogenesis hence prompting us to study GDF15 further. Here we report gdf15 expression both at the RNA and protein levels, in normal prostatic tissues of wild type (wt) and prostatic intraepithelial neoplasia (PIN) of transgenic (Tg) 12T-7s model mice during embryonic, postnatal, and adult prostate formation up to 15 weeks after birth. Dynamic changes in expression, at both the mRNA and protein level, correlated with cell proliferation and differentiation during distinct phases of normal mouse prostate development and alterations in the dynamics of gdf15 expression correlated with the changes in development resulting in PIN formation. Most notably mature gdf15 protein was significantly elevated during hyperplasia and PIN development. Changes in the protein levels did not always correlate well with the mRNA levels. This was more prominent during PIN than during normal prostate development suggesting that this may also be an indicator of disturbed regulation of gdf15 in PIN. We propose that gdf15 is a growth factor with dual function either promoting proliferation or growth arrest and differentiation due most likely to differences in cellular differentiation. Because of the differentiation defect in PIN its epithelium no longer responds to gdf15 by cellular growth arrest as does the normal epithelium and gdf may even stimulate proliferation. The data supports our hypothesis that GDF15 plays a role in the early stages of human prostate cancer.

Glucosamine modulates chondrocyte proliferation, matrix synthesis, and gene expression

OBJECTIVE

To investigate the effects of glucosamine (GlcN) on chondrocyte proliferation, matrix production, and gene expression for providing insights into the biochemical basis of its reported beneficial effects in osteoarthritis (OA).

METHODS

Dose-dependent effect of GlcN on cell morphology, proliferation, cartilage matrix production and gene expression was examined by incubating primary bovine chondrocytes with various amounts of GlcN in monolayers (2D) and in cell-laden hydrogels (3D constructs). Histology, immunofluorescent staining and biochemical analyses were used to determine the effect of GlcN on cartilage matrix production in 3D constructs. The impact of GlcN on gene expression was evaluated with real-time polymerase chain reaction (PCR).

RESULTS

GlcN concentration and culture conditions significantly affected the cell behavior. Quantitative detection of matrix production in cell-laden hydrogels indicated a relatively narrow window of GlcN concentration that promotes matrix production (while limiting cellular proliferation, but not cell viability). Notably, GlcN enhanced cartilage specific matrix components, aggrecan and collagen type II, in a dose-dependent manner up to 2 mM but the effect was lost by 15 mM. Additionally, GlcN treatment up-regulated transforming growth factor-beta1 (TGF-beta1) mRNA levels.

CONCLUSION

Results indicate that culture conditions play a significant role in determining the effect of GlcN on chondrocytes, explaining both the previously reported beneficial and deleterious effects of this sugar. The ability of GlcN to alter TGF-beta1 signaling provides a biochemical mechanism for GlcN activity on chondrocytes that up to now has remained elusive. The observed anabolic effect of optimal GlcN concentrations on chondrocytes may be useful in formulating effective cartilage repair strategies.

Pathophysiological model for chronic low back pain integrating connective tissue and nervous system mechanisms

Although chronic low back pain (cLBP) is increasingly recognized as a complex syndrome with multifactorial etiology, the pathogenic mechanisms leading to the development of chronic pain in this condition remain poorly understood. This article presents a new, testable pathophysiological model integrating connective tissue plasticity mechanisms with several well-developed areas of research on cLBP (pain psychology, postural control, neuroplasticity). We hypothesize that pain-related fear leads to a cycle of decreased movement, connective tissue remodeling, inflammation, nervous system sensitization and further decreased mobility. In addition to providing a new, testable framework for future mechanistic studies of cLBP, the integration of connective tissue and nervous system plasticity into the model will potentially illuminate the mechanisms of a variety of treatments that may reverse these abnormalities by applying mechanical forces to soft tissues (e.g. physical therapy, massage, chiropractic manipulation, acupuncture), by changing specific movement patterns (e.g. movement therapies, yoga) or more generally by increasing activity levels (e.g. recreational exercise). Non-invasive measures of connective tissue remodeling may eventually become important tools to evaluate and follow patients with cLBP in research and clinical practice. An integrative mechanistic model incorporating behavioral and structural aspects of cLBP will strengthen the rationale for a multidisciplinary treatment approach including direct mechanical tissue stimulation, movement reeducation, psychosocial intervention and pharmacological treatment to address this common and debilitating condition.

Functional role of transforming growth factor-β type III receptor during palatal fusion

The molecular regulation of palatogenesis continues to be an active area of investigation to provide a foundation for understanding the molecular etiology of cleft palate. Transforming growth factor (TGF) -beta type III receptor (TbetaR-III) has been shown to be specifically expressed in the medial edge epithelium at critical stages of palatal shelf adherence during palatogenesis. The aim of this study was to examine TbetaR-III mRNA localization and expression levels in vivo and to determine the requirement for TbetaR-III expression during palatal fusion in vitro. TbetaR-III gene expression was analyzed by in situ hybridization in tissue specimens and real-time reverse transcriptase-polymerase chain reaction using specific cells in the palatal shelf isolated by laser capture microdissection. TbetaR-III was knocked down in embryonic day (E) 13 palatal shelves in organ culture. Palatal shelf organ cultures were treated with small interfering RNA (siRNA) at final concentrations of 300, 400, and 500 nM, respectively. The treatment with siRNA specific for TbetaR-III decreased the amount of protein by approximately 75%. The reduction in TbetaR-III resulted in a delay in the process of palatal fusion compared with control. The protein expression of phospho-Smad2 was decreased in the TbetaR-III siRNA group. In addition, palatal organ cultures treated with TbetaR-III siRNA + rhTGF-beta3 completely fused by 72 hr in vitro. These results support our hypothesis that TbetaR-III has a critical role in the process of palatal fusion.

Transforming growth factor-beta: innately bipolar

Widely heralded for depressing ongoing immune responses, renewed interest in the proficiency by which transforming growth factor beta (TGF-beta) not only engages but also might drive an over-reactive innate response highlights its bipolar nature. Although coordination of the development and function of Treg, in addition to direct inhibition of cellular activation, are prominent pathways by which TGF-beta controls adaptive immunity, paradoxically TGF-beta appears instrumental in initiation of host responses to invasion through recruitment and activation of immune cells and persuasion of Th17 lineage commitment. Nevertheless, true to its manic-depressive behavior, new evidence links TGF-beta with depression of innate cells, including NK cells, and by way of a potential bridge between mast cells and Treg. Disruption of the tenuous balance between these opposing actions of TGF-beta underlies immunopathogenicity.

The role of growth/differentiation factor 5 (GDF5) in the induction and survival of midbrain dopaminergic neurones: relevance to Parkinson's disease treatment

Growth/differentiation factor-5 (GDF5) is a member of the transforming growth factor-beta superfamily which has potent effects on dopaminergic neurones in vitro and in vivo. GDF5 is under investigation as a potential therapeutic agent for Parkinson's disease (PD), which is caused by the progressive degeneration of dopaminergic neurones projecting from the substantia nigra (SN) to the striatum. In the rat ventral mesencephalon (VM; the developing SN), GDF5 expression peaks at embryonic day 14, the time at which dopaminergic neurones undergo terminal differentiation. Addition of GDF5 protein to cultures of embryonic rat VM increases the survival and improves the morphology of dopaminergic neurones in these cultures. GDF5 treatment also increases the number of cells which adopt a dopaminergic phenotype in cultures of VM progenitor cells. Intracerebral administration of GDF5 has potent neuroprotective and restorative effects on the nigrostriatal pathway in animal models of PD. Furthermore, addition of GDF5 protein to embryonic rat dopaminergic neuronal transplants improves their survival and function in a rat model of PD. Thus, GDF5 has potential applications to PD therapy as a dopaminergic neuroprotective agent and as a factor that may induce a dopaminergic neuronal fate in unrestricted progenitor cells.

Hematopoiesis controlled by distinct TIF1gamma and Smad4 branches of the TGFbeta pathway

Tissue homeostasis in mammals relies on powerful cytostatic and differentiation signals delivered by the cytokine TGFbeta and relayed within the cell via the activation of Smad transcription factors. Formation of transcription regulatory complexes by the association of Smad4 with receptor-phosphorylated Smads 2 and 3 is a central event in the canonical TGFbeta pathway. Here we provide evidence for a branching of this pathway. The ubiquitious nuclear protein Transcriptional Intermediary Factor 1gamma (TIF1gamma) selectively binds receptor-phosphorylated Smad2/3 in competition with Smad4. Rapid and robust binding of TIF1gamma to Smad2/3 occurs in hematopoietic, mesenchymal, and epithelial cell types in response to TGFbeta. In human hematopoietic stem/progenitor cells, where TGFbeta inhibits proliferation and stimulates erythroid differentiation, TIF1gamma mediates the differentiation response while Smad4 mediates the antiproliferative response with Smad2/3 participating in both responses. Thus, Smad2/3-TIF1gamma and Smad2/3-Smad4 function as complementary effector arms in the control of hematopoietic cell fate by the TGFbeta/Smad pathway.

Actions of TGF-beta as tumor suppressor and pro-metastatic factor in human cancer

Transforming growth factor-beta (TGF-beta) is a secreted polypeptide that signals via receptor serine/threonine kinases and intracellular Smad effectors. TGF-beta inhibits proliferation and induces apoptosis in various cell types, and accumulation of loss-of-function mutations in the TGF-beta receptor or Smad genes classify the pathway as a tumor suppressor in humans. In addition, various oncogenic pathways directly inactivate the TGF-beta receptor-Smad pathway, thus favoring tumor growth. On the other hand, all human tumors overproduce TGF-beta whose autocrine and paracrine actions promote tumor cell invasiveness and metastasis. Accordingly, TGF-beta induces epithelial-mesenchymal transition, a differentiation switch that is required for transitory invasiveness of carcinoma cells. Tumor-derived TGF-beta acting on stromal fibroblasts remodels the tumor matrix and induces expression of mitogenic signals towards the carcinoma cells, and upon acting on endothelial cells and pericytes, TGF-beta regulates angiogenesis. Finally, TGF-beta suppresses proliferation and differentiation of lymphocytes including cytolytic T cells, natural killer cells and macrophages, thus preventing immune surveillance of the developing tumor. Current clinical approaches aim at establishing novel cancer drugs whose mechanisms target the TGF-beta pathway. In conclusion, TGF-beta signaling is intimately implicated in tumor development and contributes to all cardinal features of tumor cell biology.

Effect of gamma interferon on lung function of mustard gas exposed patients, after 15 years

BACKGROUND

Bronchiolitis has been known to be among the main the pathological features of lung lesions in Mustard Gas (MG) exposed patients. The purpose of this research was to evaluate the efficacy of interferon gamma-1b on the lung function in MG exposed patients with bronchiolitis.

METHOD

Thirty-six bronchiolitis patients, whose lung lesion had been diagnosed through High Resolution Computerized Tomography (HRCT) of the chest and also pathological study, were divided into two 18-member case and control groups. Both groups were receiving their conventional treatment (inhaled Felixotide and Servent). The case group were treated for 6 months with a combination of 200 microg of interferon gamma-1b (given three times per week subcutaneously) plus 7.5 mg of prednisolone (given once a day), while the control group received their previous conventional medications. Lung function was measured at base line and after 1, 3 and 6 months of treatment.

RESULTS

In case and control groups, Forced Expiratory Volume in first second (FEV1) did not have statistical differences at the base line (49.3 +/- 2.9 and 48.7 +/- 4.1, respectively = 0.6), whereas a significant increase was seen in the case group (66.3 +/- 5.4) compared control group (57.3 +/- 8.6) at the subsequent months (P = 0.001 for the difference between the groups). Similar pattern of increase was observed in Forced Vital Capacity (FVC).

CONCLUSION

The findings of this study indicate that a 6-month treatment with interferon gamma-1b plus a low-dose prednisolone is associated with an improvement in the lung function in mustard-gas exposed patients with bronchiolitis.

Progesterone-dependent release of transforming growth factor-beta1 from epithelial cells enhances the endometrial decidualization by turning on the Smad signalling in stromal cells

Endometrial decidualization results from the differentiation of stromal cells in an ovarian steroid-sensitive manner. Human endometrial tissues obtained from fertile women at various stages of the menstrual cycle were subjected to immunohistochemistry to localize the components of the transforming growth factor-beta (TGF-beta) system. TGF-beta receptor-I and -II expression was higher in stromal cells than in epithelial cells during the secretory phase while no such variation was observed during the proliferative phase. The expression of phosphorylated Smad3 (pSmad2/3), an activated form of a component of the TGF-beta signalling pathway, and translocation of pSmad2/3 from the cytoplasm to the nucleus were more pronounced in secretory endometrium. In coculture of human endometrial epithelial with stromal cells, each isolated from the proliferative endometrium, administration of progesterone stimulated decidualization as well as TGF-beta signalling activation in stromal cells. Progesterone also significantly elevated the concentration of TGF-beta1 in the coculture medium. Careful manipulation of the coculture, i.e. selective addition and omission of the cellular components, showed that this progesterone-induced increase in secretion of TGF-beta1 come mainly from epithelial cells. Moreover, administration of TGF-beta1 (10 ng/ml) directly to cultured stromal cells enhanced the expression of prolactin as well as pSamd2/3 even without progesterone. Taken together, our present data support the notion that progesterone induces stromal decidualization indirectly, i.e. by enhancing the expression and secretion of TGF-beta1 from epithelial cells. The secreted, epithelial-derived TGF-beta1 then acts on adjacent stromal cells, at least in part, to turn on Smad signalling that could lead to stromal decidualization.

Effect of salt intake on progression of chronic kidney disease

PURPOSE OF REVIEW

The attempt of this review is to bring into focus the potential role of dietary salt intake in progression of chronic kidney disease.

RECENT FINDINGS

Ongoing work has elucidated a role for dietary salt intake in modulating intrarenal production of transforming growth factor-beta1. The mechanism is independent of angiotensin II and systemic blood pressure and involves activation of vascular endothelium by dietary salt intake with release of this growth factor. In this model, transforming growth factor-beta1 serves an autacoid function by stimulating nitric oxide production by the endothelium. In turn, endothelium-derived nitric oxide modulates production of this growth factor. The model further predicts that individuals who have lost the requisite endothelial cell flexibility to adapt to this environmental stress (a high salt diet) are potentially at increased risk of developing end-organ damage from excess salt intake. Animal and human studies are presented to support this working hypothesis.

SUMMARY

Overproduction of transforming growth factor-beta1 permits excess biological activity of this important fibrogenic growth factor with subsequent development or acceleration of vascular and kidney damage. In patients with diseases whose pathogenesis is related to excess production of transforming growth factor-beta1, such as chronic allograft nephropathy and diabetic nephropathy, increased salt intake may hasten loss of function, particularly if nitric oxide production does not increase. The role that endothelial cell plasticity plays in altering vascular tone and renal function, especially in response to changes in dietary salt intake, should be examined further in chronic kidney disease.

Combined genetic assessment of transforming growth factor-beta signaling pathway variants may predict breast cancer risk

There is growing evidence that common variants of the transforming growth factor-beta (TGF-beta) signaling pathway may modify breast cancer risk. In vitro studies have shown that some variants increase TGF-beta signaling, whereas others have an opposite effect. We tested the hypothesis that a combined genetic assessment of two well-characterized variants may predict breast cancer risk. Consecutive patients (n = 660) with breast cancer from the Memorial Sloan-Kettering Cancer Center (New York, NY) and healthy females (n = 880) from New York City were genotyped for the hypomorphic TGFBR1*6A allele and for the TGFB1 T29C variant that results in increased TGF-beta circulating levels. Cases and controls were of similar ethnicity and geographic location. Thirty percent of cases were identified as high or low TGF-beta signalers based on TGFB1 and TGFBR1 genotypes. There was a significantly higher proportion of high signalers (TGFBR1/TGFBR1 and TGFB1*CC) among controls (21.6%) than cases (15.7%; P = 0.003). The odds ratio [OR; 95% confidence interval (95% CI)] for individuals with the lowest expected TGF-beta signaling level (TGFB1*TT or TGFB1*TC and TGFBR1*6A) was 1.69 (1.08-2.66) when compared with individuals with the highest expected TGF-signaling levels. Breast cancer risk incurred by low signalers was most pronounced among women after age 50 years (OR, 2.05; 95% CI, 1.01-4.16). TGFBR1*6A was associated with a significantly increased risk for breast cancer (OR, 1.46; 95% CI, 1.04-2.06), but the TGFB1*CC genotype was not associated with any appreciable risk (OR, 0.89; 95% CI, 0.63-1.21). TGFBR1*6A effect was most pronounced among women diagnosed after age 50 years (OR, 2.20; 95% CI, 1.25-3.87). This is the first study assessing the TGF-beta signaling pathway through two common and functionally relevant TGFBR1 and TGFB1 variants. This approach may predict breast cancer risk in a large subset of the population.

Expression of truncated latent TGF-beta-binding protein modulates TGF-beta signaling

Transforming growth factor-beta is released from most cells as an inactive complex consisting of transforming growth factor-beta, the transforming growth factor-beta propeptide and the latent transforming growth factor-beta-binding protein. We studied the role of latent transforming growth factor-beta-binding protein in modulating transforming growth factor-beta availability by generating transgenic mice that express a truncated form of latent transforming growth factor-beta-binding protein-1 that binds to transforming growth factor-beta but is missing the known N- and C-terminal matrix-binding sequences. As transforming growth factor-beta is an inhibitor of keratinocyte proliferation and is involved in the control of hair cycling, we over-expressed the mutated form of latent transforming growth factor-beta-binding protein under the control of the keratin 14-promoter. Transgenic animals displayed a hair phenotype due to a reduction in keratinocyte proliferation, an abbreviated growth phase and an early initiation of the involution (catagen) phase of the hair cycle. This phenotype appears to result from excess active transforming growth factor-beta, as enhanced numbers of pSmad2/3-positive nuclei are observed in transgenic animal skin. These data suggest that the truncated form of latent transforming growth factor-beta-binding protein-1 competes with wild-type latent transforming growth factor-beta-binding protein for binding to latent transforming growth factor-beta, resulting in latent transforming growth factor-beta complexes that fail to be targeted correctly in the extracellular matrix. The mis-localization of the transforming growth factor-beta results in inappropriate activation and premature initiation of catagen, thereby illustrating the significance of latent transforming growth factor-beta-binding protein interaction with transforming growth factor-beta in the targeting and activation of latent transforming growth factor-beta in addition to previously reported effects on small latent complex secretion.