TGF beta -1, -2 and -3 in the modulation of fibrosis in the cornea and other organs.

The TGF beta-1, -2 and -3 isoforms are transcribed from different genes but bind to the same receptors and signal through the same canonical and non-canonical signal transduction pathways. There are numerous regulatory mechanisms controlling the action of each isoform that include the organ-specific cells producing latent TGF beta growth factors, multiple effectors that activate the isoforms, ECM-associated SLRPs and basement membrane components that modulate the activity and localization of the isoforms, other interactive cytokine-growth factor receptor systems, such as PDGF and CTGF, TGF beta receptor expression on target cells, including myofibroblast precursors, receptor binding competition, positive and negative signal transduction effectors, and transcription and translational regulatory mechanisms. While there has long been the view that TGF beta-1and TGF beta-2 are pro-fibrotic, while TGF beta-3 is anti-fibrotic, this review suggests that view is too simplistic, at least in adult tissues, since TGF beta-3 shares far more similarities in its modulation of fibrotic gene expression with TGF beta-1 and TGF beta-2, than it does differences, and often the differences are subtle. Rather, TGF beta-3 should be seen as a fibro-modulatory partner to the other two isoforms that modulates a nuanced and better controlled response to injury. The complex interplay between the three isoforms and numerous interactive proteins, in the context of the cellular milieu, controls regenerative non-fibrotic vs. fibrotic healing in a response to injury in a particular organ, as well as the resolution of fibrosis, when that occurs.

Transcriptional analysis of cleft palate in TGFß3 mutant mice.

Cleft palate (CP) is one of the most common craniofacial birth defects, impacting about 1 in 800 births in the USA. Tgf-ß3 plays a critical role in regulating murine palate development, and Tgf-ß3 null mutants develop cleft palate with 100% penetrance. In this study, we compared global palatal transcriptomes of wild type (WT) and Tgf-ß3 -/- homozygous (HM) mouse embryos at the crucial palatogenesis stages of E14.5, and E16.5, using RNA-seq data. We found 1,809 and 2,127 differentially expressed genes at E16.5 vs. E14.5 in the WT and HM groups, respectively (adjusted p < 0.05; |fold change|> 2.0). We focused on the genes that were uniquely up/downregulated in WT or HM at E16.5 vs. E14.5 to identify genes associated with CP. Systems biology analysis relating to cell behaviors and function of WT and HM specific genes identified functional non-Smad pathways and preference of apoptosis to epithelial-mesenchymal transition. We identified 24 HM specific and 11 WT specific genes that are CP-related and/or involved in Tgf-ß3 signaling. We validated the expression of 29 of the 35 genes using qRT-PCR and the trend of mRNA expression is similar to that of RNA-seq data . Our results enrich our understanding of genes associated with CP that are directly or indirectly regulated via TGF-ß.

SMAD2 overexpression rescues the TGF-ß3 null mutant mice cleft palate by increased apoptosis.

During palatal development, medial edge epithelium (MEE) disappearance is one of the crucial steps in the process of fusion. The fate of these cells is still debated, and controversies remain. During secondary palate fusion, TGF-ß3 signaling mediated in the cell through the SMAD2 protein plays an important role and leads to the disappearance of the midline epithelial seam (MES) and the confluence of the palatal mesenchyme. In mice, TGF-ß3 knock-out is lethal and mice are born with a cleft in the secondary palate. This phenotype has been rescued by targeted overexpression of SMAD2 in the medial edge epithelium (MEE). The goal of this research was to understand the mechanism of palatal fusion in the rescue mice. METHODS: The heads of embryos with four different genotypes (wild-type, K14-SMAD2/TGF-ß3(-/-), K14-SMAD2/TGF-ß3(±), and TGF-ß3 null) were collected at embryonic day E14.5, genotyped, fixed and embedded in paraffin. Serial sections were studied for detection of apoptosis and epithelial mesenchymal transition using immunofluorescence. RESULTS: TGF-ß3 null mice developed a cleft in the secondary palate while both mice with K14-SMAD2 overexpression had fusion of the secondary palate. The MEE of both the rescue mice and K14-SMAD2 overexpression had a much higher ratio of apoptotic cells than wild-type mice. The increase in apoptosis was correlated with increased phospho-SMAD2 in the MEE. CONCLUSION: SMAD2 overexpression rescued the cleft in the secondary palate by increasing apoptosis in the medial edge epithelium.

Developmental pathways of periodontal tissue regeneration: Developmental diversities of tooth morphogenesis do also map capacity of periodontal tissue regeneration?

Nothing is known on the impact of developmental divergence on periodontal tissue regeneration in vertebrate animals. Molecularly, the induction of tooth morphogenesis is highly conserved deploying across animal phyla a constant and reproducible set of gene pathways, which result in morphogenesis of multiple odontode forms and shapes. Genetic mutations positively affect animal speciation via evolving biting and masticatory forces as well as dietary habits selectively imprinted in animal phyla during evolutionary speciation. The geometry of the attachment apparatus of a tooth is important for the interpretation of the induction of cementogenesis with de novo Sharpey's fibres as in thecodonty, ie, a tripartite attachment of alveolar bone, periodontal ligament and cementum. This review addresses the tooth implantation in different animal clades from the fibrous attachment of the Elasmobranch Carcharinus obscurus dusky shark, reviewing the evolution and functional significance of cementum with functionally inserted Sharpey's fibres. In sharks there is a continuous tooth replacement mechanistically supported by the continuously erupting dental lamina. We show that the arching of the continuously erupting dental lamina, a critical step for the selachians' tooth differentiation, is prominently characterized by transforming growth factor-ß3 (TGF-ß3 ) expression not only within the dental lamina but also in cellular condensations in the mesenchymal tissues of the erupting tooth. Such findings indicate the pleiotropic multifaceted activity of a highly conserved mammalian gene across genera, masterminding tooth morphogenesis in both selachians and mammals as well as periodontal tissue induction in the non-human primate Papio ursinus. In P. ursinus, the induction of cementogenesis entails the expression of TGF-ß3 and osteocalcin with fine-tuning and regulation of bone morphogenetic proteins BMP-2 and BMP-7, and upregulation of TGF-ß3 . TGF-ß3 autoinduction and upregulation during the induction of cementogenesis and osteogenesis in P. ursinus provide novel insights into the induction of cementogenesis. It is hypothesized that the evolutionary expression and upregulation of the TGF-ß3 gene may provide the mechanistic insights into the induction of extensive cementogenesis as seen in stem mammals and the induction of trabecular-like cementum formation in mosasaurs' tooth attachment. Aspidin, the precursor of cementum, was reported to appear 310-330 million years ago (Ma) in Odontostraci armoured fish. Studies showed that the differentiation of cementum with inserted Sharpey's fibres is also present in lower amniotes such as Diatectomorpha or Diadectidae, the first herbivorous tetrapods, 323 Ma. In mosasaurs, 168-165 Ma, there is the induction of extensive trabeculation of cementum though nothing is known on the phylogenetic temporo-spatial evolution of cementum before Diadectidae and stem mammals. The large trabeculations of cementum as seen in the attachment of extinct mosasaurs invocates a pleiotropic capacity of cemental growth previously unknown. The appearance of cementum facing a vascularized and innervated periodontal ligament space with Sharpey's fibres inserting on to mineralized cementum provides a multiform pleiotropic masticatory apparatus adapted to multiple biting and lacerating forces as well as finely tuned and controlled forces beyond mastication and deglutition. The remarkable cementogenesis as seen in stem mammals but particularly in mosasaurs with cemental trabeculations across the ligament space invocates the developmental capacity of cementum. The large cemental trabeculations as seen in mosasaurs and the cemental growth in stem mammals, together with regenerating scenarios in P. ursinus with large seams of cellular cementum and cementoid populated by contiguous cementoblasts indicate the continuous molecular cross-talk between cementum, newly formed cementoid matrix, cementoblasts and extracellular matrix soluble molecular signals. This molecular cross-talk may control the biomolecular homeostasis of both cementum and periodontal ligament, including angiogenesis. A further molecular scenario is invocated by the tight and exquisite anatomical relationships between the cementoid surfaces and the newly formed capillaries. The primitiveness of the craniate masticatory mineralized craniofacial apparatus has been controlled by several yet ancestral common genes not lastly the TGF-ß3 gene. The TGF-ß3 might have been responsible for the induction of cementogenesis not only in extant P. ursinus but also in Diatectomorpha and mosasaurs, thus providing continuous evolutionary mechanisms for the induction of tissue morphogenesis across animal phyla for almost a billion years of evolution, epitomizing Nature's parsimony in controlling tissue induction and morphogenesis. TGF-ß receptor II regulates osterix expression via Smad-dependent pathways indicating that TGF-ß signalling acts as an upstream regulator of osterix during cementoblast differentiation. The presence of morphogenetic signals within the cemental matrix capable of inducing bone formation needs now to be assigned: bone induction initiated by extracted and partially purified cemental matrices may be the result of a slow release of embryonic remnants of osteogenic signals required and deployed during cementogenesis. The cementum may thus rule the periodontal ligament space homeostasis, remodelling and repair by releasing sequestered morphogenetic signals that were deployed during embryogenesis.

Transforming Growth Factor-ß3 Regulates Adipocyte Number in Subcutaneous White Adipose Tissue.

White adipose tissue (WAT) mass is determined by adipocyte size and number. While adipocytes are continuously turned over, the mechanisms controlling fat cell number in WAT upon weight changes are unclear. Herein, prospective studies of human subcutaneous WAT demonstrate that weight gain increases both adipocyte size and number, but the latter remains unaltered after weight loss. Transcriptome analyses associate changes in adipocyte number with the expression of 79 genes. This gene set is enriched for growth factors, out of which one, transforming growth factor-ß3 (TGFß3), stimulates adipocyte progenitor proliferation, resulting in a higher number of cells undergoing differentiation in vitro. The relevance of these observations was corroborated in vivo where Tgfb3+/- mice, in comparison with wild-type littermates, display lower subcutaneous adipocyte progenitor proliferation, WAT hypertrophy, and glucose intolerance. TGFß3 is therefore a regulator of subcutaneous adipocyte number and may link WAT morphology to glucose metabolism.

In Vitro Repair of Meniscal Radial Tear With Hydrogels Seeded With Adipose Stem Cells and TGF-ß3.

BACKGROUND: Radial tears of the meniscus are a common knee injury, frequently resulting in osteoarthritis. To date, there are no established, effective treatments for radial tears. Adipose-derived stem cells (ASCs) may be an attractive cell source for meniscal regeneration because they can be quickly isolated in large number and are capable of undergoing induced fibrochondrogenic differentiation mediated by transforming growth factor ß3 (TGF-ß3). However, the use of ASCs for meniscal repair is largely unexplored. HYPOTHESIS: ASC-seeded hydrogels with preloaded TGF-ß3 will improve meniscal healing of radial tears, as modeled in an explant model. STUDY DESIGN: Controlled laboratory study. METHODS: With an institutional review board-exempted protocol, human ASCs were isolated from the infrapatellar fat pads of 3 donors, obtained after total knee replacement, and characterized. ASCs were encapsulated in photocrosslinkable methacrylated gelatin hydrogels to form 3-dimensional constructs, which were placed into tissue culture. The effect of TGF-ß3-whether preloaded into the hydrogel or added as a soluble medium supplement-on matrix-sulfated proteoglycan deposition in the constructs was evaluated. A meniscal explant culture model was used to simulate meniscal repair. Cylindrical-shaped explants were excised from the inner avascular region of adult bovine menisci, and a radial tear was modeled by cutting perpendicular to the meniscal main fibers to the length of the radius. Six combinations of hydrogels-namely, acellular and ASC-seeded hydrogels supplemented with preloaded TGF-ß3 (2 µg/mL) or soluble TGF-ß3 (10 ng/mL) and without supplement-were injected into the radial tear and stabilized by photocrosslinking with visible light. At 4 and 8 weeks of culture, healing was assessed through histology, immunofluorescence staining, and mechanical testing. RESULTS: ASCs isolated from the 3 donors exhibited colony-forming and multilineage differentiation potential. Hydrogels preloaded with TGF-ß3 and those cultured in soluble TGF-ß3 showed robust matrix-sulfated proteoglycan deposition. ASC-seeded hydrogels promoted superior healing as compared with acellular hydrogels, with preloaded or soluble TGF-ß3 further improving histological scores and mechanical properties. CONCLUSION: These findings demonstrated that ASC-seeded hydrogels preloaded with TGF-ß3 enhanced healing of radial meniscal tears in an in vitro meniscal repair model. CLINICAL RELEVANCE: Injection delivery of ASCs in a TGF-ß3-preloaded photocrosslinkable hydrogel represents a novel candidate strategy to repair meniscal radial tears and minimize further osteoarthritic joint degeneration.

PDGFRα Is a Key Regulator of T1 and T3's Differential Effect on SMA Expression in Human Corneal Fibroblasts.

Purpose: The goal of this study was to examine the mechanism behind the unique differential action of transforming growth factor ß3 (TGF-ß3) and TGF-ß1 on SMA expression. It was our hypothesis that platelet-derived growth factor receptor α (PDGFRα) played a key role in determining TGF-ß3's response to wounding. Methods: A stable cell line, human corneal fibroblast (HCF)-P, was created from HCFs by knocking down PDGFRα expression using a lentivirus-delivered shRNA sequence. A three-dimensional (3D) in vitro model was constructed by culturing HCF or HCF-P on poly-transwell membranes for 4 weeks in the presence and absence of 0.1 ng/mL TGF-ß1 or -ß3. At the end of 4 weeks, the constructs were processed for immunofluorescence and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, HCF and HCF-P cell migration was evaluated. Results: In HCF, TGF-ß3 treatment resulted in significantly lower α-smooth muscle actin (SMA) mRNA expression and immunolocalization when compared to TGF-ß1, while in HCF-P, both TGF-ß1 and -ß3 treatment increased the SMA mRNA expression and immunolocalization compared to both the untreated HCF-P control and TGF-ß3-treated HCF. Human corneal fibroblast-P also had a lower migration rate and construct thickness when compared to HCF. Conclusions: These results show that TGF-ß3 decreases SMA in HCF, while remarkably increasing SMA in HCF-P, thus indicating that the presence or absence of PDGFRα elicits contrasting responses to the same TGF-ß3 treatment. Understanding the role of PDGFRα in TGF-ß3's ability to stimulate SMA may potentially help in understanding the differential functions of TGF-ß1 and TGF-ß3 in corneal wound healing.

Investigating ego modules involved in TGFß3-induced chondrogenesis in mesenchymal stem cells based on ego network.

OBJECTIVE: This paper aimed to investigate ego modules for TGFß3-induced chondrogenesis in mesenchymal stem cells (MSCs) using ego network algorithm. METHODS: The ego network algorithm comprised three parts, extracting differential expression network (DEN) based on gene expression data and protein-protein interaction (PPI) data; exploring ego genes by reweighting DEN; and searching ego modules by ego gene expansions. Subsequently, permutation test was carried out to evaluate the statistical significance of the ego modules. Finally, pathway enrichment analysis was conducted to investigate ego pathways enriched by the ego modules. RESULTS: A total of 15 ego genes were obtained from the DEN, such as PSMA4, HNRNPM and WDR77. Starting with each ego genes, 15 candidate modules were gained. When setting the thresholds of the area under the receiver operating characteristics curve (AUC) ≥0.9 and gene size ≥4, three ego modules (Module 3, Module 8 and Module 14) were identified, and all of them had statistical significances between normal and TGFß3-induced chondrogenesis in MSCs. By mapping module genes to confirmed pathway database, their ego pathways were detected, Cdc20:Phospho-APC/C mediated degradation of Cyclin A for Module 3, Mitotic G1-G1/S phases for Module 8, and mRNA Splicing for Module 14. CONCLUSIONS: We have successfully identified three ego modules, evaluated their statistical significances and investigated their functional enriched ego pathways. The findings might provide potential biomarkers and give great insights to reveal molecular mechanism underlying this process.

TGF-ß3-induced miR-494 inhibits macrophage polarization via suppressing PGE2 secretion in mesenchymal stem cells.

Abnormal macrophage polarization at the maternal-fetal interface may contribute to the development of Preeclampsia (PE). The reason why macrophage polarization changed in PE is still unclear. Decidual mesenchymal stem cells (dMSCs) could regulate macrophage polarization. However, miRNA in dMSCs of PE were maladjusted. Therefore, we speculated that miRNA may affect dMSC-regulated macrophage polarization. In this study, we found that miR-494-overexpressed dMSCs inhibit M2 macrophage polarization and this inhibitory effect is mediated by miR-494-reduced PGE2 secretion. Furthermore, we proved that miR-494 is induced by TGF-ß3. In summary, our findings suggest that the high expression of TGF-ß3 in PE decidua stimulates miR-494 in dMSCs and attenuates the regulation of MSC switching the macrophage toward M2 type, contributing to an immune imbalance at maternal-fetal interface.

Molecular insights on the effect of TGF-ß1/-ß3 in human corneal fibroblasts.

Transforming growth factor ß (TGF-ß) plays a critical role in wound healing and the pathogenesis of fibrosis (scarring). Three isoforms of TGF-ß have been identified in mammals. Previous studies have shown that the addition of TGF-ß1 (T1) or -ß2 (T2) to human corneal fibroblasts (HCF) cultured in a 3-dimensional construct resulted in a fibrotic matrix, while the addition of TGF-ß3 (T3) resulted in the production of enhanced non-fibrotic matrix as compared to control (Vitamin C [VitC] only). In the current investigation, we undertook the molecular comparison of fibrosis-related gene expression in T1 or T3-treated HCF to gain further insights into the regulation and roles of these two isoforms on the fibrotic response. HCF were cultured in 100 mm dishes in basic medium (Eagles minimum essential medium [EMEM] with 10% fetal bovine serum [FBS]). At 70-80% confluency, cells were exposed to basic medium with 0.5 mM 2-O-α-d-glucopyranosyl-l-ascorbic acid (VitC) ± 2 ng/ml of T1 or T3. After 4 h or 3 days, cells were harvested, and mRNA or protein was isolated. Fibrosis related mRNA levels were assayed using a commercial qRT-PCR Array. Selected proteins were examined using Western blotting (WB). Experiments were performed 6 times for the qRT-PCR and 4 times for WB for each condition. qRT-PCR results showed that most of the fibrosis-related genes were up or downregulated in HCF exposed to T1 or T3 as compared with VitC control. At 4 h, only Smad7 expression was significantly altered in T3-treated HCF, compared to T1, and at 3 days, five genes were altered. WB confirmed that T1 significantly decreased Smad7 expression compared to T3 and control, and that the expression of thrombospondin-1 in T3-stimulated HCF was enhanced compared to T1-treated cells. Finally, both T1 and T3 decreased Smad3 expression dramatically at both time points. At early time points, T1 and T3 have similar effects on expression of fibrosis related genes; however, with a longer exposure, an increasing number of genes were differentially expressed. Interestingly, most of the differentially expressed gene products are secreted by the cells and may be related to the modulation of extracellular matrix.

Mammary epithelial cell phagocytosis downstream of TGF-ß3 is characterized by adherens junction reorganization.

After weaning, during mammary gland involution, milk-producing mammary epithelial cells undergo apoptosis. Effective clearance of these dying cells is essential, as persistent apoptotic cells have a negative impact on gland homeostasis, future lactation and cancer susceptibility. In mice, apoptotic cells are cleared by the neighboring epithelium, yet little is known about how mammary epithelial cells become phagocytic or whether this function is conserved between species. Here we use a rat model of weaning-induced involution and involuting breast tissue from women, to demonstrate apoptotic cells within luminal epithelial cells and epithelial expression of the scavenger mannose receptor, suggesting conservation of phagocytosis by epithelial cells. In the rat, epithelial transforming growth factor-ß (TGF-ß) signaling is increased during involution, a pathway known to promote phagocytic capability. To test whether TGF-ß enhances the phagocytic ability of mammary epithelial cells, non-transformed murine mammary epithelial EpH4 cells were cultured to achieve tight junction impermeability, such as occurs during lactation. TGF-ß3 treatment promoted loss of tight junction impermeability, reorganization and cleavage of the adherens junction protein E-cadherin (E-cad), and phagocytosis. Phagocytosis correlated with junction disruption, suggesting junction reorganization is necessary for phagocytosis by epithelial cells. Supporting this hypothesis, epithelial cell E-cad reorganization and cleavage were observed in rat and human involuting mammary glands. Further, in the rat, E-cad cleavage correlated with increased γ-secretase activity and ß-catenin nuclear localization. In vitro, pharmacologic inhibitors of γ-secretase or ß-catenin reduced the effect of TGF-ß3 on phagocytosis to near baseline levels. However, ß-catenin signaling through LiCl treatment did not enhance phagocytic capacity, suggesting a model in which both reorganization of cell junctions and ß-catenin signaling contribute to phagocytosis downstream of TGF-ß3. Our data provide insight into how mammary epithelial cells contribute to apoptotic cell clearance, and in light of the negative consequences of impaired apoptotic cell clearance during involution, may shed light on involution-associated breast pathologies.

Biological activity differences between TGF-ß1 and TGF-ß3 correlate with differences in the rigidity and arrangement of their component monomers.

TGF-ß1, -ß2, and -ß3 are small, secreted signaling proteins. They share 71-80% sequence identity and signal through the same receptors, yet the isoform-specific null mice have distinctive phenotypes and are inviable. The replacement of the coding sequence of TGF-ß1 with TGF-ß3 and TGF-ß3 with TGF-ß1 led to only partial rescue of the mutant phenotypes, suggesting that intrinsic differences between them contribute to the requirement of each in vivo. Here, we investigated whether the previously reported differences in the flexibility of the interfacial helix and arrangement of monomers was responsible for the differences in activity by generating two chimeric proteins in which residues 54-75 in the homodimer interface were swapped. Structural analysis of these using NMR and functional analysis using a dermal fibroblast migration assay showed that swapping the interfacial region swapped both the conformational preferences and activity. Conformational and activity differences were also observed between TGF-ß3 and a variant with four helix-stabilizing residues from TGF-ß1, suggesting that the observed changes were due to increased helical stability and the altered conformation, as proposed. Surface plasmon resonance analysis showed that TGF-ß1, TGF-ß3, and variants bound the type II signaling receptor, TßRII, nearly identically, but had small differences in the dissociation rate constant for recruitment of the type I signaling receptor, TßRI. However, the latter did not correlate with conformational preference or activity. Hence, the difference in activity arises from differences in their conformations, not their manner of receptor binding, suggesting that a matrix protein that differentially binds them might determine their distinct activities.

Regional divergence of palate medial edge epithelium along the anterior to posterior axis.

Recent studies have shown that mouse palatal mesenchymal cells undergo regional specification along the anterior-posterior (A-P) axis defined by anterior Shox2 and Msx1 expression and posterior Meox2 expression. A-P regional specification of the medial edge epithelium, which is directly responsible for palate fusion, has long been proposed, but it has not yet been demonstrated due to the lack of regional specific markers. In this study, we have demonstrated that the palate medial edge epithelium is regionalized along the A-P axis, similar to that for the underlying mesenchyme. Mmp13, a medial edge epithelium specific marker, was uniformly expressed from anterior to posterior in wild-type mouse palatal shelves. Previous studies demonstrated that medial edge epithelium expression of Mmp13 was regulated by TGF-beta3. We have found that the changes in Mmp13 expression in TGF-beta3 knockouts varied along the A-P axis, and can be broken down into three distinct regions. These regions correlated with regional specification of the underlying medial edge mesenchymal cells and timing of palate fusion. Mouse palate medial edge epithelium along the A-P axis can be divided into different regions according to the differential response to the loss of TGF-beta3.

The type III TGFß receptor regulates filopodia formation via a Cdc42-mediated IRSp53-N-WASP interaction in epithelial cells.

Cell adhesion and migration are tightly controlled by regulated changes in the actin cytoskeleton. Previously we reported that the TGFß (transforming growth factor ß) superfamily co-receptor, TßRIII (type III TGFß receptor; also known as ßglycan), regulates cell adhesion, migration and invasion, and suppresses cancer progression, in part, through activation of the small GTPase Cdc42 (cell division cycle 42), and Cdc42-dependent alterations to the actin cytoskeleton. In the present study we demonstrate that TßRIII specifically promotes filopodial formation and extension in MCF10A and HMEC (human mammary epithelial cell) mammary epithelial cells. Mechanistically, cell-surface TßRIII and Cdc42 co-localize to filopodial structures and co-complex in a ß-arrestin2-dependent, and a TßRI/TßRII-independent manner. The ß-arrestin2-mediated interaction between TßRIII and Cdc42 increases complex formation between the Cdc42 effectors IRSp53 with N-WASP (neuronal Wiskott-Aldrich syndrome protein) to increase filopodial formation. We demonstrate a function link between filopodial structures and epithelial cell adhesion as regulated by the TßRIII-Cdc42 interaction. The present studies identify TßRIII as a novel regulator of IRSp53/N-WASP via Cdc42 to regulate filopodial formation and cell adhesion.

Loss of muscleblind-like 1 promotes invasive mesenchyme formation in endocardial cushions by stimulating autocrine TGFß3.

BACKGROUND: Valvulogenesis and septation in the developing heart depend on the formation and remodeling of endocardial cushions in the atrioventricular canal (AVC) and outflow tract (OFT). These cushions are invaded by a subpopulation of endocardial cells that undergo an epithelial-mesenchymal transition in response to paracrine and autocrine transforming growth factor ß (TGFß) signals. We previously demonstrated that the RNA binding protein muscleblind-like 1 (MBNL1) is expressed specifically in the cushion endocardium, and knockdown of MBNL1 in stage 14 embryonic chicken AVC explants enhances TGFß-dependent endocardial cell invasion. RESULTS: In this study, we demonstrate that the effect of MBNL1 knockdown on invasion remains dependent on TGFß3 after it is no longer required to induce basal levels of invasion. TGFß3, but not TGFß2, levels are elevated in medium conditioned by MBNL1-depleted AVC explants. TGFß3 is elevated even when the myocardium is removed, indicating that MBNL1 modulates autocrine TGFß3 production in the endocardium. More TGFß3-positive cells are observed in the endocardial monolayer following MBNL1 knockdown. Addition of exogenous TGFß3 to AVC explants recapitulates the effects of MBNL1 knockdown. Time course experiments demonstrate that knockdown of MBNL1 induces precocious TGFß3 secretion, and early exposure to excess TGFß3 induces precocious invasion. MBNL1 expression precedes TGFß3 in the AVC endocardium, consistent with a role in preventing precocious autocrine TGFß3 signaling. The stimulatory effects of MBNL1 knockdown on invasion are lost in stage 16 AVC explants. Knockdown of MBNL1 in OFT explants similarly enhances cell invasion, but not activation. TGFß is necessary and sufficient to mediate this effect. CONCLUSIONS: Taken together, these data support a model in which MBNL1 negatively regulates cell invasion in the endocardial cushions by restricting the magnitude and timing of endocardial-derived TGFß3 production.

TGF-ß mediates proinflammatory seminal fluid signaling in human cervical epithelial cells.

The cervix is central to the female genital tract immune response to pathogens and foreign male Ags introduced at coitus. Seminal fluid profoundly influences cervical immune function, inducing proinflammatory cytokine synthesis and leukocyte recruitment. In this study, human Ect1 cervical epithelial cells and primary cervical cells were used to investigate agents in human seminal plasma that induce a proinflammatory response. TGF-ß1, TGF-ß2, and TGF-ß3 are abundant in seminal plasma, and Affymetrix microarray revealed that TGF-ß3 elicits changes in Ect1 cell expression of several proinflammatory cytokine and chemokine genes, replicating principal aspects of the Ect1 response to seminal plasma. The differentially expressed genes included several induced in the physiological response of the cervix to seminal fluid in vivo. Notably, all three TGF-ß isoforms showed comparable ability to induce Ect1 cell expression of mRNA and protein for GM-CSF and IL-6, and TGF-ß induced a similar IL-6 and GM-CSF response in primary cervical epithelial cells. TGF-ß neutralizing Abs, receptor antagonists, and signaling inhibitors ablated seminal plasma induction of GM-CSF and IL-6, but did not alter IL-8, CCL2 (MCP-1), CCL20 (MIP-3α), or IL-1α production. Several other cytokines present in seminal plasma did not elicit Ect1 cell responses. These data identify all three TGF-ß isoforms as key agents in seminal plasma that signal induction of proinflammatory cytokine synthesis in cervical cells. Our findings suggest that TGF-ß in the male partner's seminal fluid may influence cervical immune function after coitus in women, and potentially be a determinant of fertility, as well as defense from infection.

2-Methoxyestradiol causes functional repression of transforming growth factor ß3 signaling by ameliorating Smad and non-Smad signaling pathways in immortalized uterine fibroid cells.

OBJECTIVE: To investigate the effects and the mechanism of action of 2-methoxyestradiol (2ME(2)) on transforming growth factor (TGF) ß3-induced profibrotic response in immortalized human uterine fibroid smooth muscle (huLM) cells. DESIGN: Laboratory study. SETTING: University research laboratory. PATIENTS(S): Not applicable. INTERVENTIONS(S): Not applicable. MAIN OUTCOME MEASURE(S): huLM cells were treated with TGF-ß3 (5 ηg/mL) in the presence or absence of specific Smad3 inhibitor SIS3 (1 µmol/L), inhibitor of the PI3K/Akt (LY294002, 10 µmol/L), or 2ME(2) (0.5 µmol/L), and the expression of collagen (Col) type I(αI), Col III(αI), plasminogen activator inhibitor (PAI) 1, connective tissue growth factor (CTGF), and α-smooth muscle actin (α-SMA) were determined by real-time reverse-transcription polymerase chain reaction and immunoblotting. The effect of 2ME(2) on Smad-microtubule binding was evaluated by coimmunoprecipitation. RESULT(S): Our data revealed that TGF-ß3-induced fibrogenic response in huLM is mediated by both Smad-dependent and Smad-independent PI3K/Akt/mTOR signaling pathways. 2ME(2) abrogates TGF-ß3-induced expression of Col I(αI), Col III(αI), PAI-1, CTGF, and α-SMA. Molecularly, 2ME(2) ameliorates TGF-ß3-induced Smad2/3 phosphorylation and nuclear translocation. In addition, 2ME(2) inhibits TGF-ß3-induced activation of the PI3K/Akt/mTOR pathway. CONCLUSION(S): TGF-ß3-induced profibrotic response in fibroid cells is mediated by Smad-dependent and Smad-independent PI3K/Akt/mTOR pathways. 2ME(2) inhibits TGF-ß3 profibrotic effects in huLM cells by ameliorating both Smad-dependent and Smad-independent signaling pathways.

Modulation of epithelial tight junctions by TGF-beta 3 in cultured oral epithelial cells.

BACKGROUND: Previous studies have indicated that transforming growth factor beta 3 (TGF-ß3) was strongly expressed both in the gingival epithelium and the poorly structured pocket epithelium. METHODS: A comprehensive analysis of the profile of tight junction proteins was carried out by quantitative real-time RT-PCR, Western blot and paracellular permeability assays. RESULTS: Active TGF-ß3 protein added to monolayers of cultured oral epithelial cells initially reduced the permeability to dextran (10 kDa), followed by an increase in permeability. Three hours after the addition of TGF-ß3, expression of genes encoding tight junction components was selectively up- or down-regulated. In addition, up- or down-regulation of expression of several tight junction associated proteins was observed, although the protein changes did not parallel changes in gene expression. To confirm that TGF-ß3 plays a role in epithelial barrier function, a selective Src family kinase inhibitor saracatinib (AZD0530) was added to cells treated with active TGF-ß3. Tight junction proteins claudins-2, -20 and ZO-2 were significantly decreased, but claudin-4 and -18 were significantly increased. CONCLUSIONS: These results suggest that TGF-ß3 is involved in the modulation of epithelial barrier function by regulating assembly of tight junctions.

Modulation of YY1 and p53 expression by transforming growth factor-ß3 in prostate cell lines.

Transforming growth factor-ß (TGF-ß) is the prototype of a family of secreted polypeptide growth factors. These cytokines play very important roles during development, as well as in normal physiological and disease processes, by regulating a wide array of cellular processes, such as cell growth, differentiation, migration, apoptosis, and extracellular matrix production. TGF-ß utilizes a multitude of intracellular signalling pathways in addition to Smads with actions that are dependent on circumstances, including dose, target cell type, and context. The aims of this research were (i) to verify the effects of dose-dependent TGF-ß3 treatment on YY1 and p53 expression, in BPH-1 cell line, human benign prostate hyperplasia, and two prostate cancer cell lines, LNCaP, which is androgen-sensitive, and DU-145, which is androgen-non responsive, (ii) establish a correlation between p53 and YY1 and (iii) determine the expression of a number of important intracellular signalling pathways in TGF-ß3-treated prostate cell lines. The expression of YY1, p53, PI3K, AKT, pAKT, PTEN, Bcl-2, Bax, and iNOS was evaluated through Western blot analysis on BPH-1, LNCaP, and DU-145 cultures treated with 10 and 50 ng/ml of TGF-ß3 for 24 h. The production of nitric oxide (NO) was determined by Griess reagent and cell viability through MTT assay. The results of this research demonstrated profound differences in the responses of the BPH-1, LNCaP, and DU-145 cell lines to TGF-ß3 stimulation. We believe that the findings could be important because of the clinical relevance that they may assume and the therapeutic implications for TGF-ß treatment of prostate cancer.