TGF-beta receptors and actions

Mutual Inhibition of Antithrombin III and SARS-CoV-2 Cellular Attachment to Syndecans: Implications for COVID-19 Treatment and Vaccination

Antithrombin III (ATIII) is a potent endogenous anticoagulant that binds to heparan sulfate proteoglycans (HSPGs) on endothelial cells' surfaces. Among these HSPGs, syndecans (SDCs) are crucial as transmembrane receptors bridging extracellular ligands with intracellular signaling pathways. Specifically, syndecan-4 (SDC4) has been identified as a key receptor on endothelial cells for transmitting the signaling effects of ATIII. Meanwhile, SDCs have been implicated in facilitating the cellular internalization of SARS-CoV-2. Given the complex interactions between ATIII and SDC4, our study analyzed the impact of ATIII on the virus entry into host cells. While ATIII binds to all SDC isoforms, it shows the strongest affinity for SDC4. SDCs' heparan sulfate chains primarily influence ATIII's SDC attachment, although other parts might also play a role in ATIII's dominant affinity toward SDC4. ATIII significantly reduces SARS-CoV-2's cellular entry into cell lines expressing SDCs, suggesting a competitive inhibition mechanism at the SDC binding sites, particularly SDC4. Conversely, the virus or its spike protein decreases the availability of SDCs on the cell surface, reducing ATIII's cellular attachment and hence contributing to a procoagulant environment characteristic of COVID-19.

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Recent progress in the manipulation of biochemical and biophysical cues for engineering functional tissues

Tissue engineering (TE) is currently considered a cutting-edge discipline that offers the potential for developing treatments for health conditions that negatively affect the quality of life. This interdisciplinary field typically involves the combination of cells, scaffolds, and appropriate induction factors for the regeneration and repair of damaged tissue. Cell fate decisions, such as survival, proliferation, or differentiation, critically depend on various biochemical and biophysical factors provided by the extracellular environment during developmental, physiological, and pathological processes. Therefore, understanding the mechanisms of action of these factors is critical to accurately mimic the complex architecture of the extracellular environment of living tissues and improve the efficiency of TE approaches. In this review, we recapitulate the effects that biochemical and biophysical induction factors have on various aspects of cell fate. While the role of biochemical factors, such as growth factors, small molecules, extracellular matrix (ECM) components, and cytokines, has been extensively studied in the context of TE applications, it is only recently that we have begun to understand the effects of biophysical signals such as surface topography, mechanical, and electrical signals. These biophysical cues could provide a more robust set of stimuli to manipulate cell signaling pathways during the formation of the engineered tissue. Furthermore, the simultaneous application of different types of signals appears to elicit synergistic responses that are likely to improve functional outcomes, which could help translate results into successful clinical therapies in the future.

The Role of Cytokinome in the HNSCC Tumor Microenvironment: A Narrative Review and Our Experience

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer. In locally advanced (LA) HNSCC, a multidisciplinary approach consisting of surgery followed by chemoradiation (CRT) or definitive CRT is the mainstay of treatment. In recurrent metastatic (R/M), HNSCC immune checkpoint inhibitors (ICIs) with or without chemotherapy represent the new first-line option. However, cancer will recur in about two out of five patients with LA HNSCC. If progression occurs within six months from platin-radiotherapy treatment, anti-programmed cell death-1 (PD-1) may be prescribed. Otherwise, immunotherapy with or without chemotherapy might be considered if PD-L1 is expressed. Despite several improvements in the outcome of patients with R/M HNSCC, overall survival (OS) remains dismal, equaling a median of 14 months. In-depth knowledge of the tumor microenvironment (TME) would be required to change the course of this complex disease. In recent years, many predictive and prognostic biomarkers have been studied in the HNSCC TME, but none of them alone can select the best candidates for response to ICIs or targeted therapy (e.g., Cetuximab). The presence of cytokines indicates an immune response that might occur, among other things, after tumor antigen recognition, viral and bacterial infection, and physic damage. An immune response against HNSCC results in the production of some cytokines that induce a pro-inflammatory response and attract cells, such as neutrophils, macrophages, and T cell effectors, to enhance the innate and adaptive anti-tumor response. We revised the role of a group of cytokines as biomarkers for treatment response in HNSCC.

Immune Inhibitory Properties and Therapeutic Prospects of Transforming Growth Factor-Beta and Interleukin 10 in Autoimmune Hepatitis

Transforming growth factor-beta and interleukin 10 have diverse immune inhibitory properties that have restored homeostatic defense mechanisms in experimental models of autoimmune disease. The goals of this review are to describe the actions of each cytokine, review their investigational use in animal models and patients, and indicate their prospects as interventions in autoimmune hepatitis. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Transforming growth factor-beta expands the natural and inducible populations of regulatory T cells, limits the proliferation of natural killer cells, suppresses the activation of naïve CD8⁺ T cells, decreases the production of interferon-gamma, and stimulates fibrotic repair. Interleukin 10 selectively inhibits the CD28 co-stimulatory signal for antigen recognition and impairs antigen-specific activation of uncommitted CD4⁺ and CD8⁺ T cells. It also inhibits maturation of dendritic cells, suppresses Th17 cells, supports regulatory T cells, and limits production of diverse pro-inflammatory cytokines. Contradictory immune stimulatory effects have been associated with each cytokine and may relate to the dose and accompanying cytokine milieu. Experimental findings have not translated into successful early clinical trials. The recombinant preparation of each agent in low dosage has been safe in human studies. In conclusion, transforming growth factor-beta and interleukin 10 have powerful immune inhibitory actions of potential therapeutic value in autoimmune hepatitis. The keys to their therapeutic application will be to match their predominant non-redundant function with the pivotal pathogenic mechanism or cytokine deficiency and to avoid contradictory immune stimulatory actions.

Progress of Statin Therapy in the Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a type of interstitial lung disease (ILD) characterized by the proliferation of fibroblasts and aberrant accumulation of extracellular matrix. These changes are accompanied by structural destruction of the lung tissue and the progressive decline of pulmonary function. In the past few decades, researchers have investigated the pathogenesis of IPF and sought a therapeutic approach for its treatment. Some studies have shown that the occurrence of IPF is related to pulmonary inflammatory injury; however, its specific etiology and pathogenesis remain unknown, and no effective treatment, with the exception of lung transplantation, has been identified yet. Several basic science and clinical studies in recent years have shown that statins, the traditional lipid-lowering drugs, exert significant antifibrotic effects, which can delay the progression of IPF and impairment of pulmonary function. This article is aimed at summarizing the current understanding of the pathogenesis of IPF, the progress of research on the use of statins in IPF models and clinical trials, and its main molecular targets.

A bioinformatic analysis of the inhibin-betaglycan-endoglin/CD105 network reveals prognostic value in multiple solid tumors

Inhibins and activins are dimeric ligands belonging to the TGFβ superfamily with emergent roles in cancer. Inhibins contain an α-subunit (INHA) and a β-subunit (either INHBA or INHBB), while activins are mainly homodimers of either βA (INHBA) or βB (INHBB) subunits. Inhibins are biomarkers in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Given the array of prior reports on inhibin, activin and the coreceptors in cancer, this study aims to provide a comprehensive analysis, assessing their functional prognostic potential in cancer using a bioinformatics approach. We identify cancer cell lines and cancer types most dependent and impacted, which included p53 mutated breast and ovarian cancers and lung adenocarcinomas. Moreover, INHA itself was dependent on TGFBR3 and ENG/CD105 in multiple cancer types. INHA, INHBA, TGFBR3, and ENG also predicted patients' response to anthracycline and taxane therapy in luminal A breast cancers. We also obtained a gene signature model that could accurately classify 96.7% of the cases based on outcomes. Lastly, we cross-compared gene correlations revealing INHA dependency to TGFBR3 or ENG influencing different pathways themselves. These results suggest that inhibins are particularly important in a subset of cancers depending on the coreceptor TGFBR3 and ENG and are of substantial prognostic value, thereby warranting further investigation.

Betaglycan (TβRIII) is a Key Factor in TGF-β2 Signaling in Prepubertal Rat Sertoli Cells

Transforming growth factor-βs (TGF-βs) signal after binding to the TGF-β receptors TβRI and TβRII. Recently, however, betaglycan (BG) was identified as an important co-receptor, especially for TGF-β2. Both proteins are involved in several testicular functions. Thus, we analyzed the importance of BG for TGF-β1/2 signaling in Sertoli cells with ELISAs, qRT-PCR, siRNA silencing and BrdU assays. TGF-β1 as well as TGF-β2 reduced shedding of membrane-bound BG (mBG), thus reducing the amount of soluble BG (sBG), which is often an antagonist to TGF-β signaling. Treatment of Sertoli cells with GM6001, a matrix metalloproteinases (MMP) inhibitor, also counteracted BG shedding, thus suggesting MMPs to be mainly involved in shedding. Interestingly, TGF-β2 but not TGF-β1 enhanced secretion of tissue inhibitor of metalloproteinases 3 (TIMP3), a potent inhibitor of MMPs. Furthermore, recombinant TIMP3 attenuated BG shedding. Co-stimulation with TIMP3 and TGF-β1 reduced phosphorylation of Smad3, while a combination of TIMP3/TGF-β2 increased it. Silencing of BG as well as TIMP3 reduced TGF-β2-induced phosphorylation of Smad2 and Smad3 significantly, once more highlighting the importance of BG for TGF-β2 signaling. In contrast, this effect was not observed with TIMP3/TGF-β1. Silencing of BG and TIMP3 decreased significantly Sertoli cell proliferation. Taken together, BG shedding serves a major role in TGF-β2 signaling in Sertoli cells.

Contribution of syndecans to cellular uptake and fibrillation of α-synuclein and tau

Scientific evidence suggests that α-synuclein and tau have prion-like properties and that prion-like spreading and seeding of misfolded protein aggregates constitutes a central mechanism for neurodegeneration. Heparan sulfate proteoglycans (HSPGs) in the plasma membrane support this process by attaching misfolded protein fibrils. Despite of intense studies, contribution of specific HSPGs to seeding and spreading of α-synuclein and tau has not been explored yet. Here we report that members of the syndecan family of HSPGs mediate cellular uptake of α-synuclein and tau fibrils via a lipid-raft dependent and clathrin-independent endocytic route. Among syndecans, the neuron predominant syndecan-3 exhibits the highest affinity for both α-synuclein and tau. Syndecan-mediated internalization of α-synuclein and tau depends heavily on conformation as uptake via syndecans start to dominate once fibrils are formed. Overexpression of syndecans, on the other hand, reduces cellular uptake of monomeric α-synuclein and tau, yet exerts a fibril forming effect on both proteins. Data obtained from syndecan overexpressing cellular models presents syndecans, especially the neuron predominant syndecan-3, as important mediators of seeding and spreading of α-synuclein and tau and reveal how syndecans contribute to fundamental molecular events of α-synuclein and tau pathology.

Non-HLA Genetic Factors and Their Influence on Heart Transplant Outcomes: A Systematic Review

Supplemental digital content is available in the text.

Background

Improvement of immunosuppressive therapies and surgical techniques has increased the survival rate after heart transplantation. Nevertheless, a large number of patients still experience complications, such as allograft rejection, vasculopathy, kidney dysfunction, and diabetes in response to immunosuppressive therapy. Variants in HLA genes have been extensively studied for their role in clinical outcomes after transplantation, whereas the knowledge about non-HLA genetic variants in this setting is still limited. Non-HLA polymorphisms are involved in the metabolism of major immunosuppressive therapeutics and may play a role in clinical outcomes after cardiac transplantation. This systematic review summarizes the existing knowledge of associations between non-HLA genetic variation and heart transplant outcomes.

Methods

The current evidence available on genetic polymorphisms associated with outcomes after heart transplantation was identified by a systematic search in PubMed and Embase. Studies reporting on polymorphisms significantly associated with clinical outcomes after cardiac transplantation were included.

Results

A total of 56 studies were included, all were candidate gene studies. These studies identified 58 polymorphisms in 36 genes that were associated with outcomes after cardiac transplantation. Variants in TGFB1, CYP3A5, and ABCB1 are consistently replicated across multiple studies for various transplant outcomes.

Conclusions

The research currently available supports the hypothesis that non-HLA polymorphisms are associated with clinical outcomes after heart transplantation. However, many genetic variants were only identified in a single study, questioning their true effect on the clinical outcomes tested. Further research in larger cohorts with well-defined phenotypes is warranted.

Contribution of syndecans to cellular internalization and fibrillation of amyloid-β(1-42)

Intraneuronal accumulation of amyloid-β(1-42) (Aβ1-42) is one of the earliest signs of Alzheimer's disease (AD). Cell surface heparan sulfate proteoglycans (HSPGs) have profound influence on the cellular uptake of Aβ1-42 by mediating its attachment and subsequent internalization into the cells. Colocalization of amyloid plaques with members of the syndecan family of HSPGs, along with the increased expression of syndecan-3 and -4 have already been reported in postmortem AD brains. Considering the growing evidence on the involvement of syndecans in the pathogenesis of AD, we analyzed the contribution of syndecans to cellular uptake and fibrillation of Aβ1-42. Among syndecans, the neuron specific syndecan-3 isoform increased cellular uptake of Aβ1-42 the most. Kinetics of Aβ1-42 uptake also proved to be fairly different among SDC family members: syndecan-3 increased Aβ1-42 uptake from the earliest time points, while other syndecans facilitated Aβ1-42 internalization at a slower pace. Internalized Aβ1-42 colocalized with syndecans and flotillins, highlighting the role of lipid-rafts in syndecan-mediated uptake. Syndecan-3 and 4 also triggered fibrillation of Aβ1-42, further emphasizing the pathophysiological relevance of syndecans in plaque formation. Overall our data highlight syndecans, especially the neuron-specific syndecan-3 isoform, as important players in amyloid pathology and show that syndecans, regardless of cell type, facilitate key molecular events in neurodegeneration.

Effects of Transforming Growth Factor-Beta 2, Interleukin 6 and Fibronectin on Corneal Epithelial Wound Healing

Purpose

The aim of this study was to compare the effects of topically applied transforming growth factor-beta 2 (TGF-beta 2) and interleukin 6 (IL-6), alone and combined with fibronectin, on the rate of corneal wound healing in rabbits.

Methods

Twenty-eight rabbits were used for the experiment. After the right eye of each rabbit was debrided with n-heptyl alcohol, the animals were divided into four treatment groups (six rabbits per group) and one control group (four rabbits). The debrided eyes were treated, beginning immediately after wounding and continuing every 2 hours from 8 a.m. to 8 p.m. for 48 hours. Group 1 received TGF-beta 2; group 2 IL-6; group 3, TFR-beta 2 and purified fibronectin; group 4, IL-6 and fibronectin; control group, balanced salt solution. At set intervals each eye was stained with fluorescein and photographed; epithelial defects were measured with a computer-assisted digitizer. The healing rate was calculated by linear regression analysis.

Results

The mean healing rates in groups 1, 2, 3, 4, and controls were respectively 1.65 ± 0.16, 1.68 ± 0.11, 1.99 ± 0.12, 2.23 ± 0.09, and 0.93 ± 0.18 mm2/h. Mean epithelial healing rates for all drug-treatment groups were significantly faster than controls. The healing rates of groups 3 and 4 were significantly faster than groups 1 and 2.

Conclusions

We conclude that cytokines, in combination with extracellular matrix proteins, facilitate corneal epithelial wound healing in vivo, possibly by making corneal epithelial cells more sensitive to fibronectin receptors.

Human Chorionic Gonadotrophin as a Possible Mediator of Leiomyoma Growth during Pregnancy: Molecular Mechanisms

Uterine fibroids are the most common gynecologic benign tumors. Studies supporting a strong pregnancy-related growth of leiomyomas generally claimed a crucial role of sex steroid hormones. However, sex steroids are unlikely the unique actors involved as estrogen and progesterone achieve a pick serum concentration in the last trimester while leiomyomas show a typical increase during the first trimester. Given the rapid exponential raise in serum human Chorionic Gonadotrophin (hCG) at the beginning of gestation, we conducted a review to assess the potential role of hCG in the striking growth of leiomyomas during initial pregnancy. Fibroid growth during initial pregnancy seems to correlate to the similar increase of serum hCG levels until 12 weeks of gestation. The presence of functional Luteinizing Hormone/human Chorionic Gonadotropin (LH/hCG) receptors was demonstrated on leiomyomas. In vitro treatment of leiomyoma cells with hCG determines an up to 500% increase in cell number after three days. Expression of cyclin E and cyclin-dependent kinase 1 was significantly increased in leiomyoma cells by hCG treatment. Moreover, upon binding to the receptor, hCG stimulates prolactin secretion in leiomyoma cells, promoting cell proliferation via the mitogen-activated protein kinase cascade. Fibroid enlargement during initial pregnancy may be regulated by serum hCG.

Activin receptor type 2A (ACVR2A) functions directly in osteoblasts as a negative regulator of bone mass

Bone and skeletal muscle mass are highly correlated in mammals, suggesting the existence of common anabolic signaling networks that coordinate the development of these two anatomically adjacent tissues. The activin signaling pathway is an attractive candidate to fulfill such a role. Here, we generated mice with conditional deletion of activin receptor (ACVR) type 2A, ACVR2B, or both, in osteoblasts, to determine the contribution of activin receptor signaling in regulating bone mass. Immunohistochemistry localized ACVR2A and ACVR2B to osteoblasts and osteocytes. Primary osteoblasts expressed activin signaling components, including ACVR2A, ACVR2B, and ACVR1B (ALK4) and demonstrated increased levels of phosphorylated Smad2/3 upon exposure to activin ligands. Osteoblasts lacking ACVR2B did not show significant changes in vitro However, osteoblasts deficient in ACVR2A exhibited enhanced differentiation indicated by alkaline phosphatase activity, mineral deposition, and transcriptional expression of osterix, osteocalcin, and dentin matrix acidic phosphoprotein 1. To investigate activin signaling in osteoblasts in vivo, we analyzed the skeletal phenotypes of mice lacking these receptors in osteoblasts and osteocytes (osteocalcin-Cre). Similar to the lack of effect in vitro, ACVR2B-deficient mice demonstrated no significant change in any bone parameter. By contrast, mice lacking ACVR2A had significantly increased femoral trabecular bone volume at 6 weeks of age. Moreover, mutant mice lacking both ACVR2A and ACVR2B demonstrated sustained increases in trabecular bone volume, similar to those in ACVR2A single mutants, at 6 and 12 weeks of age. Taken together, these results indicate that activin receptor signaling, predominantly through ACVR2A, directly and negatively regulates bone mass in osteoblasts.

Bone morphogenetic proteins in tumour associated angiogenesis and implication in cancer therapies

Bone morphogenetic protein (BMP) belongs to transforming growth factor-β superfamily. To date, more than 20 BMPs have been identified in humans. BMPs play a critical role in embryonic and postnatal development, and also in maintaining homeostasis in different organs and tissues by regulating cell differentiation, proliferation, survival and motility. They play important roles in the development and progression of certain malignancies, including prostate cancer, breast cancer, lung cancer, etc. Recently, more evidence shows that BMPs are also involved in tumour associated angiogenesis. For example BMP can either directly regulate the functions of vascular endothelial cells or indirectly influence the angiogenesis via regulation of angiogenic factors, such as vascular endothelial growth factor (VEGF). Such crosstalk can also be reflected in the interaction with other angiogenic factors, like hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF). All these factors are involved in the orchestration of the angiogenic process during tumour development and progression. Review of the relevant studies will provide a comprehensive prospective on current understanding and shed light on the corresponding therapeutic opportunity.

Repulsive guidance molecules (RGMs) and neogenin in bone morphogenetic protein (BMP) signaling

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta (TGFβ) superfamily. BMPs mediate a highly conserved signal transduction cascade through the type-I and type-II serine/threonine kinase receptors and intracellular Smad proteins, which regulate multiple developmental and homeostatic processes. Mutations in this pathway can cause various diseases in humans, such as skeletal disorders, cardiovascular diseases, and various cancers. Multiple levels of regulation, including extracellular regulation, help to ensure proper spatiotemporal control of BMP signaling in the right cellular context. The family of repulsive guidance molecules (RGMs) and the type-I transmembrane protein neogenin, a paralog of DCC (Deleted in Colorectal Cancer), have been implicated in modulating the BMP pathway. In this review, we discuss the properties and functions of RGM proteins and neogenin, focusing on their roles in the modulation of BMP signal transduction.

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.

Bone morphogenetic proteins: periodontal regeneration

Periodontitis is an infectious inflammatory disease that results in attachment loss and bone loss. Regeneration of the periodontal tissues entails de novo formation of cementum, periodontal ligament, and alveolar bone. Several different approaches are currently being explored to achieve complete, reliable, and reproducible regeneration of periodontal tissues. The therapeutic management of new bone formation is one of the key issues in successful periodontal regeneration. Bone morphogenetic proteins form a unique group of proteins within the transforming growth factor superfamily of genes and have a vital role in the regulation in the bone induction and maintenance. The activity of bone morphogenetic proteins was first identified in the 1960s, but the proteins responsible for bone induction were unknown until the purification and cloning of human bone morphogenetic proteins in the 1980s, because of their osteoinductive potential. Bone morphogenetic proteins have gained a lot of interest as therapeutic agents for treating periodontal defects. A systematic search for data related to the use of bone morphogenetic proteins for the regeneration of periodontal defects was performed to recognize studies on animals and human (PUBMED, MEDLINE, COCHRANE, and Google search). All the studies included showed noticeable regeneration of periodontal tissues with the use of BMP.

Cellular responses to TGFβ and TGFβ receptor expression in human colonic epithelial cells require CaSR expression and function

CaSR and TGFβ are robust promoters of differentiation in the colonic epithelium. Loss of cellular responses to TGFβ or loss of CaSR expression is tightly linked to malignant progression. Human colonic epithelial CBS cells, originally developed from a differentiated human colon tumor, retain CaSR expression and function, TGFβ responsiveness and TGFβ receptor expression. Thus, these cells offer a unique opportunity in determining the functional linkage (if any) between CaSR and TGFβ. Knocking down CaSR expression abrogated TGFβ-mediated cellular responses and attenuated the expression of TGFβ receptors. Ca²⁺ or vitamin D treatment induced CaSR expression with a concurrent up-regulation of TGFβ receptor expression. Ca²⁺ or vitamin D, however, did not induce CaSR in CaSR knocked down cells and without CaSR; there was no up-regulation of TGFβ receptor. It is concluded that TGFβ receptor expression and TGFβ mediated responses requires CaSR expression and function.

Response of fibroblasts to transforming growth factor-β1 on two-dimensional and in three-dimensional hyaluronan hydrogels

Transforming growth factor-β1 (TGF-β1), an important cytokine with multiple functions, is secreted during wound healing. Previous studies have utilized two-dimensional (2D) cell culture to elucidate the functions of TGF-β1; however, 2D culture does not represent the complex three-dimensional (3D) in vivo environment. Using a synthetic hyaluronan (HA) extracellular matrix (ECM) hydrogel, we investigated the effect of TGF-β1 on fibroblasts cultured in three conditions--on tissue culture polystyrene (TCP), on HA (2D), and in HA (3D). After TGF-β1 treatment (0.1 to 20 ng/mL), morphological features and ECM regulation were analyzed by immunocytochemistry, Western blot, quantitative polymerase chain reaction, and zymogram assays. On TCP, cells showed the typical spindle shape with strong alpha smooth muscle actin (α-SMA) staining of cytoplasmic myofilaments along the cell axes after TGF-β1 treatment; on HA (2D), spindle-shape cells showed little α-SMA staining; in HA (3D), cells were smaller and rounded with less α-SMA deposition. The α-SMA gene and protein expression on TCP were significantly upregulated by TGF-β1, but TGF-β1 did not induce α-SMA expression in the presence of HA (both 2D and 3D). 3D HA culture significantly downregulated collagen I, III, and fibronectin expression, increased matrix metalloproteinase 1 and 2 (MMP1/MMP2) activity, upregulated MMP1 mRNA and downregulated TIMP3 mRNA expression. This study suggested that exogenous HA, particularly in 3D culture, appears to suppress ECM production, enhances ECM degradation and remodeling, and inhibits myofibroblast differentiation without decreasing TGF-β receptor expression.

Serotonin potentiates transforming growth factor-beta3 induced biomechanical remodeling in avian embryonic atrioventricular valves

Embryonic heart valve primordia (cushions) maintain unidirectional blood flow during development despite an increasingly demanding mechanical environment. Recent studies demonstrate that atrioventricular (AV) cushions stiffen over gestation, but the molecular mechanisms of this process are unknown. Transforming growth factor-beta (TGFβ) and serotonin (5-HT) signaling modulate tissue biomechanics of postnatal valves, but less is known of their role in the biomechanical remodeling of embryonic valves. In this study, we demonstrate that exogenous TGFβ3 increases AV cushion biomechanical stiffness and residual stress, but paradoxically reduces matrix compaction. We then show that TGFβ3 induces contractile gene expression (RhoA, aSMA) and extracellular matrix expression (col1α2) in cushion mesenchyme, while simultaneously stimulating a two-fold increase in proliferation. Local compaction increased due to an elevated contractile phenotype, but global compaction appeared reduced due to proliferation and ECM synthesis. Blockade of TGFβ type I receptors via SB431542 inhibited the TGFβ3 effects. We next showed that exogenous 5-HT does not influence cushion stiffness by itself, but synergistically increases cushion stiffness with TGFβ3 co-treatment. 5-HT increased TGFβ3 gene expression and also potentiated TGFβ3 induced gene expression in a dose-dependent manner. Blockade of the 5HT2b receptor, but not 5-HT2a receptor or serotonin transporter (SERT), resulted in complete cessation of TGFβ3 induced mechanical strengthening. Finally, systemic 5-HT administration in ovo induced cushion remodeling related defects, including thinned/atretic AV valves, ventricular septal defects, and outflow rotation defects. Elevated 5-HT in ovo resulted in elevated remodeling gene expression and increased TGFβ signaling activity, supporting our ex-vivo findings. Collectively, these results highlight TGFβ/5-HT signaling as a potent mechanism for control of biomechanical remodeling of AV cushions during development.

Regulation of Krüppel-like factor 4 by the anaphase promoting complex pathway is involved in TGF-beta signaling

Krüppel-like factor 4 (KLF4), a zinc finger-containing transcriptional factor, regulates a variety of biological processes, including cell proliferation, differentiation, apoptosis, and stem cell reprogramming. Post-translational modifications of KLF4, including phosphorylation, acetylation, and sumoylation, regulate its transcriptional activity. Most recent studies also demonstrate that KLF4 is targeted for ubiquitin-dependent proteolysis during cell cycle progression. However, the underlying mechanism remains largely unknown. In this study, we demonstrated that KLF4 is profoundly degraded in response to TGF-β signaling. We have identified the Cdh1-anaphase promoting complex as a putative E3 ligase that governs TGF-β-induced KLF4 degradation. The TGF-β-induced KLF4 degradation is mediated by the destruction box on the KLF4. Either depletion of Cdh1 by RNA interference or stabilization of KLF4 by disruption of its destruction box significantly attenuates TGF-β-induced ubiquitylation and degradation. In addition, depletion of Cdh1 or stabilization of KLF4 antagonizes TGF-β-induced activation of transcription. Determining the role of KLF4 proteolysis in response to TGF-β signaling has opened a new perspective to understand the TGF-β signaling pathway.

Lentiviral-mediated RNA interference against TGF-beta receptor type II in renal epithelial and fibroblast cell populations in vitro demonstrates regulated renal fibrogenesis that is more efficient than a nonlentiviral vector

Background. Lentiviral constructs reportedly can integrate into the genome of non-dividing, terminally differentiated cells and dividing cells, for long-term gene expression. This investigation tested whether a third generation lentiviral-mediated small interfering RNA (siRNA) delivered into renal epithelial and fibroblast cells against type II transforming growth factor-beta receptor (siRNA-TBRII) could better attenuate renal fibrogenesis in comparison with a non-lentiviral construct. Methods. HIV-derived lentiviral and non-lentiviral constructs were used to transfect cells with siRNA-TBRII or siRNA-EGFP control. Human embryonic kidney (HEK-293T), renal epithelial cells (NRK-52E) and renal fibroblasts (NRK-49F) were transfected and gene silencing quantified (fluorescence microscopy, Western blotting, fluorescence-activated cell sorting). Renal fibrogenesis was assessed using extracellular matrix protein synthesis (fibronectin and collagen-III; Western immunoblot), and α-smooth muscle actin (α-SMA) was analysed as a marker of fibroblast activation and epithelial-to-mesenchymal transdifferentiation (EMT). Results. Lentiviral-mediated siRNA-TBRII significantly suppressed TBRII expression in all cell lines, and also significantly suppressed renal fibrogenesis. In comparison with the non-lentiviral construct, lentiviral-mediated siRNA-TBRII produced stronger and more persistent inhibition of collagen-III in NRK-49F cells, fibronectin in all renal cell lines, and α-SMA in renal epithelial cells. Conclusions. Lentiviral vector systems against TBRII can be delivered into renal cells to efficiently limit renal fibrogenesis by sequence-specific gene silencing.

Suppression of TGFβ-induced epithelial-mesenchymal transition like phenotype by a PIAS1 regulated sumoylation pathway in NMuMG epithelial cells

Epithelial-mesenchymal-transition (EMT) is a fundamental cellular process that is critical for normal development and tumor metastasis. The transforming growth factor beta (TGFβ) is a potent inducer of EMT like effects, but the mechanisms that regulate TGFβ-induced EMT remain incompletely understood. Using the widely employed NMuMG mammary epithelial cells as a model to study TGFβ-induced EMT, we report that TGFβ downregulates the levels of the SUMO E3 ligase PIAS1 in cells undergoing EMT. Gain and loss of function analyses indicate that PIAS1 acts in a SUMO ligase dependent manner to suppress the ability of TGFβ to induce EMT in these cells. We also find that TGFβ inhibits sumoylation of the PIAS1 substrate SnoN, a transcriptional regulator that antagonizes TGFβ-induced EMT. Accordingly, loss of function mutations of SnoN sumoylation impair the ability of SnoN to inhibit TGFβ-induced EMT in NMuMG cells. Collectively, our findings suggest that PIAS1 is a novel negative regulator of EMT and reveal that inhibition of the PIAS1-SnoN sumoylation pathway represents a key mechanism by which TGFβ induces EMT, with important implications in normal development and tumor metastasis.

Actions and interactions of progesterone and estrogen on transcriptome profiles of the bovine endometrium

The aim of our study was to analyze endometrial gene expression profiles in ovariectomized cows treated with estradiol and/or progesterone by using microarray analysis. Clustering of differentially expressed genes allowed separation into distinct hormone response patterns. These patterns could be classified into independent and interdependent actions of the steroid hormones estrogen and progesterone. The use of ovariectomized cows and external administration of hormones identified a set of genes whose regulation depends on a progesterone priming effect. The progesterone-primed estrogen response comprises gene functions such as migration, cell differentiation, and cell adhesion and therefore may play a crucial role in tissue remodeling, as one of its key regulators in the endometrium, TGFB2, is among this group of progesterone-primed genes. Functional annotation analysis of the estrogen-responsive gene clusters shows a clear dominance of functions such as cell cycle, morphogenesis, and differentiation. The functional profile of the progesterone-responsive clusters is less clear but nevertheless shows some important fertility-related terms like luteinization, oocyte maturation, and catecholamine metabolism. We looked for putative regulators of the steroid hormone response in endometrium by searching for enriched transcription factor binding sites in the promoter regions of the genes with similar hormone response profile. This analysis identified transcription factors such as SP1, NFYA, FOXA2, IRF2, ESR1, and NOBOX as candidate regulators of gene expression in bovine endometrium treated with steroid hormones. Taken together, our data provide novel insights into the regulation of bovine endometrial physiology by steroid hormones.

Fibrinogen triggers astrocyte scar formation by promoting the availability of active TGF-beta after vascular damage

Scar formation in the nervous system begins within hours after traumatic injury and is characterized primarily by reactive astrocytes depositing proteoglycans that inhibit regeneration. A fundamental question in CNS repair has been the identity of the initial molecular mediator that triggers glial scar formation. Here we show that the blood protein fibrinogen, which leaks into the CNS immediately after blood-brain barrier (BBB) disruption or vascular damage, serves as an early signal for the induction of glial scar formation via the TGF-beta/Smad signaling pathway. Our studies revealed that fibrinogen is a carrier of latent TGF-beta and induces phosphorylation of Smad2 in astrocytes that leads to inhibition of neurite outgrowth. Consistent with these findings, genetic or pharmacologic depletion of fibrinogen in mice reduces active TGF-beta, Smad2 phosphorylation, glial cell activation, and neurocan deposition after cortical injury. Furthermore, stereotactic injection of fibrinogen into the mouse cortex is sufficient to induce astrogliosis. Inhibition of the TGF-beta receptor pathway abolishes the fibrinogen-induced effects on glial scar formation in vivo and in vitro. These results identify fibrinogen as a primary astrocyte activation signal, provide evidence that deposition of inhibitory proteoglycans is induced by a blood protein that leaks in the CNS after vasculature rupture, and point to TGF-beta as a molecular link between vascular permeability and scar formation.

Tgf-Beta superfamily receptors-targets for antiangiogenic therapy?

The TGF-beta pathway controls a broad range of cellular behavior including cell proliferation, differentiation, and apoptosis of various cell types including tumor cells, endothelial cells, immune cells, and fibroblasts. Besides TGF-beta's direct effects on tumor growth and its involvement in neoangiogenesis have received recent attention. Germline mutations in TGF-beta receptors or coreceptors causing Hereditary Hemorrhagic Teleangiectasia and the Loeys-Dietz syndrome underline the involvement of TGF-beta in vessel formation and maturation. Several therapeutic approaches are evaluated at present targeting the TGF-beta pathway including utilization of antisense oligonucleotides against TGF-beta itself or antibodies or small molecule inhibitors of TGF-beta receptors. Some of these therapeutic agents have already entered the clinical arena including an antibody against the endothelium specific TGF-beta class I receptor ALK-1 targeting tumor vasculature. In conclusion, therapeutic manipulation of the TGF-beta pathway opens great opportunities in future cancer therapy.

Inhibition of type III TGF-β receptor aggravates lung fibrotic process

Transforming growth factor-beta (TGF-β) is a multifunctional cytokine that regulates cell proliferation, death, development or differentiation. In addition, TGF-β is considered a key mediator in fibrogenic processes, and signals either directly or indirectly through types I, II and III (TβRI, II, and III) receptor complexes. The type III TGF-β (TβRIII or betaglycan) is a transmembrane proteoglycan without a functional kinase domain, and is considered as a coreceptor to increase the affinity of ligand binding to TβRII. Little is studied on TGF-β and TβRIII (or betaglycan) signaling, while it is well known about TGF-β ligand and TβRII signaling. In this study, we investigated the effects of TβRIII expression on TGF-β induced differentiation, in view of the finding that TβRIII is significantly downregulated during TGF-β-induced differentiation in fibroblasts. TGF-beta induced alpha-SMA and Procollagen Type I expression were markedly inhibited in fibroblasts stably expressing TβRIII. Endogenous TβRIII expression did not alter the TβRI or TβRII levels, but inhibited Smad 2/3, Akt and ERK phosphorylation. The molecular mechanism of TβRIII action in TGF-β-induced differentiation is associated with both Smad-dependent and Smad-independent pathways. Our results suggest that TβRIII is a novel molecular target for regulation of TGF-β signaling in myofibroblast differentiation.

Cell-penetrating peptide exploited syndecans

Cell-penetrating peptides (CPPs) are short peptides capable of translocating across the plasma membrane of live cells and transporting conjugated compounds intracellularly. Fifteen years after discovering the first model cationic CPPs, penetratin and TAT, CPP internalization is still challenging many questions. Particularly it has been unknown whether CPPs enter the cells with or without mediation of a specific surface receptor. Here we report that syndecan-4, the universally expressed isoform of the syndecan family of transmembrane proteoglycans, binds and mediates transport of the three most frequently utilized cationic CPPs (penetratin, octaarginine and TAT) into the cells. Quantitative uptake studies and mutational analyses demonstrate that attachment of the cationic CPPs is mediated by specific interactions between the heparan sulfate chains of syndecan-4 and the CPPs. Protein kinase C alpha is also heavily involved in the uptake mechanism. The collected data give the first direct evidence on the receptor-mediated uptake of cationic CPPs and may replace the long-thought, but already contradicted membrane penetration hypothesis. Thus our study might give an answer for a decade long debate and foster the development of rationalized, syndecan-4 targeted novel delivery technologies.

Biomarkers for the diagnosis, prognosis, and evaluation of treatment efficacy for traumatic brain injury

Traumatic brain injury (TBI) remains a serious health concern, and TBI is one of the leading causes of death and disability, especially among young adults. Although preventive education, increased usage of safety devices, and TBI management have dramatically increased the potential for surviving a brain injury, there is still a need to develop reliable methods to diagnose TBI, the secondary pathologies associated with TBI, and predicting the outcomes of TBI. Biomarkers (changes of amount or activity in a biomolecule that reflect injury or disease) have shown promise in the diagnosis of several conditions, including cancer, heart failure, infection, and genetic disorders. A variety of proteins, small molecules, and lipid products have been proposed as potential biomarkers of brain damage from TBI. Although some of these changes have been reported to correlate with mortality and outcome, further research is required to identify prognostic biomarkers. This need is punctuated in mild injuries that cannot be readily detected using current techniques, as well as in defining patient risk for developing TBI-associated secondary injuries.

Differential expression and characterization analysis of a new gene with WD domains in fish oogenesis

A new gene with WD domains is cloned and characterized according to its differential transcription and expression between previtellogenic oocytes (phase I oocytes) and fully-grown oocytes (phase V oocytes) from natural gynogenetic silver crucian carp (Carassius auratus gibelio) by using the combinative methods of suppressive subtraction hybridization, SMART cDNA synthesis and RACE-PCR. The full-length cDNA is 1870 bp. Its 5' untranslated region is 210 bp, followed by an open reading frame of 990 bp, which has the typical vertebrate initiator codon of ANNATG. The open reading frame encodes a protein with 329 amino acids. It has 670 bp of 3' untranslated region and an AATAAA polyadenylation signal. Because it has 92% homology to STRAP (serine-threonine kinase receptor-associated protein), a recently reported gene, we named it FSTRAP (fish STRAP). Virtual Northern blotting indicated that the FSTRAP was transcribed in fully-grown oocytes (phase V oocytes), but not in previtellogenic oocytes (phase I oocytes). RT-PCR analysis showed that FSTRAP was transcribed in brain, heart, kidney, muscle, ovary, spleen and testis, but not in liver. And its mRNA could be detected in the oocytes from phase II to phase V. Western blotting also showed that FSTRAP protein could be detected in brain, heart, kidney, muscle, ovary, spleen and testis except liver. Results of Western blotting on various oocytes were also similar to the RT-PCR data. FSTRAP protein was not expressed in the previtellogenic oocytes. Its expression initiated from phase II oocytes after vitellogenesis, and was consistent with the mRNA transcription.

Biological basis of bone formation, remodeling, and repair-part I: biochemical signaling molecules

The bony biochemical environment is an active and dynamic system that permits and promotes cellular functions that lead to matrix production and ossification. Each component is capable of conveying important regulatory cues to nearby cells, thus effecting gene expression and changes at the cytostructural level. Here, we review the various signaling molecules that contribute to the active and dynamic nature of the biochemical system. These components include hormones, cytokines, and growth factors. We describe their role in regulating bone metabolism. Certain growth factors (i.e., TGF-beta, IGF-1, and VEGF) are described in greater detail because of their potential importance in developing successful tissue-engineering strategies.

Transforming growth factor beta isoforms regulation of Akt activity and XIAP levels in rat endometrium during estrous cycle, in a model of pseudopregnancy and in cultured decidual cells

BACKGROUND

During the estrous cycle, the rat uterine endometrium undergoes many changes such as cell proliferation and apoptosis. If implantation occurs, stromal cells differentiate into decidual cells and near the end of pregnancy, a second wave of apoptosis occurs. This process called decidual regression, is tightly regulated as is it crucial for successful pregnancy. We have previously shown that TGF-beta1, TGF-beta2 and TGF-beta3 are expressed in the endometrium during decidual basalis regression, but although we had demonstrated that TGF- beta1 was involved in the regulation of apoptosis in decidual cells, the ability of TGF- beta2 and TGF-beta3 isoforms to trigger apoptotic mechanisms in these cells remains unknown. Moreover, we hypothesized that the TGF-betas were also present and regulated in the non-pregnant endometrium during the estrous cycle. The aim of the present study was to determine and compare the specific effect of each TGF-beta isoform in the regulation of apoptosis in sensitized endometrial stromal cells in vitro, and to investigate the regulation of TGF-beta isoforms in the endometrium during the estrous cycle in vivo.

METHODS

Rats with regular estrous cycle (4 days) were killed at different days of estrous cycle (diestrus, proestrus, estrus and metestrus). Pseudopregnancy was induced with sex steroids in ovariectomized rats and rats were killed at different days (days 1-9). Uteri were collected and either fixed for immunohistochemical staining (IHC) or processed for RT-PCR and Western analyses. For the in vitro part of the study, rats were ovariectomized and decidualization was induced using sex steroids. Endometrial stromal decidual cells were purified, cultured and treated with different concentrations of TGF-beta isoforms.

RESULTS

Our results showed that all three TGF-beta isoforms are present, but are localized differently in the endometrium during the estrous cycle and their expression is regulated differently during pseudopregnancy. In cultured stromal cells, we found that TGF-beta3 isoform induced Smad2 phosphorylation, indicating that the Smad pathway is activated by TGF-beta3 in these cells. Furthermore, TGF-beta2 and TGF-beta3 induced a dose-dependant increase of apoptosis in cultured stromal cells, as demonstrated by Hoechst nuclear staining. Noteworthy, TGF-beta2 and TGF-beta3 reduced the level of the anti-apoptotic XIAP protein, as well as the level of phosphorylated/active Akt, a well known survival protein, in a dose-dependent manner.

CONCLUSION

Those results suggest that TGF-beta might play an important role in the remodelling endometrium during the estrous cycle and in the regulation of apoptosis in rat decidual cells, in which inhibition of Akt survival pathway might be an important mechanism involved in the regulation of apoptosis.

Molecular targets and biological modifiers in gastric cancer

The overall survival of gastric cancer patients remains poor despite efforts and advances in its prevention, diagnosis, and treatment. The development of new therapies is crucial for the effective control of this disease. An increasing number of genetic and epigenetic alterations have been associated with distinct histological types of gastric cancer. In this review, we will discuss the involvement of E-cadherin, EGFR, ERBB2, MMR genes, KRAS, and PIK3CA in the development and progression of gastric cancer and their role as biomarkers or as novel putative targets for therapy.

BAT3 interacts with transforming growth factor-beta (TGF-beta) receptors and enhances TGF-beta1-induced type I collagen expression in mesangial cells

Transforming growth factor-beta1 (TGF-beta1) plays essential roles in a wide array of cellular processes, such as in development and the pathogenesis of tissue fibrosis, including that associated with progressive kidney diseases. Tight regulation of its signaling pathways is critical, and proteins that associate with the TGF-beta receptors may exert positive or negative regulatory effects on TGF-beta signaling. In the present study we employed a yeast-based two-hybrid screening system to identify BAT3 (HLA-B-associated transcript 3) as a TGF-beta receptor-interacting protein. Analysis of endogenously expressed BAT3 in various tissues including the kidney reveals the existence of approximately 140-kDa full-length protein as well as truncated forms of BAT3 whose expression is developmentally regulated. Endogenous BAT3 protein interacts with TGF-beta receptors type I and type II in renal mesangial cells. Functional assays show that expression of full-length BAT3 results in enhancement of TGF-beta1-stimulated transcriptional activation of p3TP-Lux reporter, and these effects require the presence of functional TGF-beta signaling receptors as demonstrated in R-1B and DR-26 mutant cells. Moreover, expression of full-length BAT3, but not C-terminal truncated mutant of BAT3, enhanced TGF-beta1-induced type I collagen expression in mesangial cells, whereas knock down of BAT3 protein expression by small interfering RNA suppressed the expression of type I collagen induced by TGF-beta1. Our findings suggest that BAT3, a TGF-beta receptor-interacting protein, is capable of modulating TGF-beta signaling and acts as a positive regulator of TGF-beta1 stimulation of type I collagen expression in mesangial cells.

Estrogen deficiency, T cells and bone loss

Estrogen plays a fundamental role in the maintenance of skeletal homeostasis. Although estrogen is established to have direct effects on bone cells, animal studies have identified additional regulatory effects of estrogen centered at the level of the adaptive immune response. Furthermore, a potential role for reactive oxygen species has now been identified in both humans and animals. One of the major challenges has been to integrate a multitude of redundant pathways and cytokines, that all appear capable of playing a relevant role, into a global model of postmenopausal osteoporosis. This review presents our current understanding of the process of estrogen deficiency mediated bone destruction and explores some of the most recent findings and hypotheses to explain estrogen action in bone.

Molecular basis for skeletal variation: insights from developmental genetic studies in mice

Skeletal variations are common in humans, and potentially are caused by genetic as well as environmental factors. We here review molecular principles in skeletal development to develop a knowledge base of possible alterations that could explain variations in skeletal element number, shape or size. Environmental agents that induce variations, such as teratogens, likely interact with the molecular pathways that regulate skeletal development.

A placenta-specific gene ectopically activated in many human cancers is essentially involved in malignant cell processes

The identification and functional characterization of tumor-specific genes is a prerequisite for the development of targeted cancer therapies. Using an integrated data mining and experimental validation approach for the discovery of new targets for antibody therapy of cancer, we identified PLAC1. PLAC1 is a placenta-specific gene with no detectable expression in any other normal human tissue. However, it is frequently aberrantly activated and highly expressed in a variety of tumor types, in particular breast cancer. RNAi-mediated silencing of PLAC1 in MCF-7 and BT-549 breast cancer cells profoundly impairs motility, migration, and invasion and induces a G1-S cell cycle block with nearly complete abrogation of proliferation. Knockdown of PLAC1 is associated with decreased expression of cyclin D1 and reduced phosphorylation of AKT kinase. Moreover, PLAC1 is localized on the surface of cancer cells and is accessible for antibodies which antagonize biological functions of this molecule. These features, in summary, make PLAC1 an attractive candidate for targeted immunotherapeutic approaches.

Effect of fetuin, a TGFβ antagonist and pentoxifylline, a cytokine antagonist on hepatic stellate cell function and fibrotic parameters in fibrosis

We have previously shown that monocyte conditioned medium (MCM) from patients with liver fibrosis stimulated proliferation of hepatic stellate cells (HSCs), the major cell involved in hepatic fibrosis. To investigate the potential role of fetuin and pentoxifylline in fibrosis we used MCM samples obtained from patients with biopsy proven hepatic fibrosis related to Hepatitis C (HCV). Our results indicate that the MCM obtained from patients with HCV-related liver fibrosis significantly stimulated collagen synthesis in HSCs as assessed by tritiated proline incorporation into a collagenase sensitive trichloroacetic acid (TCA) precipitate. Collagen synthesis was also stimulated in HSCs using transforming growth factor beta (TGFbeta) and this effect was neutralized using TGFbeta antibody. Incubation of HSCs with fetuin (but not TGFbeta antibody) significantly inhibited collagen synthesis in HSCs that were stimulated by HCV MCM samples. Patient MCM samples would also stimulate proliferation of HSCs as assessed by tritiated thymidine uptake but this effect was not attenuated by fetuin. Likewise the significant stimulatory effect of platelet derived growth factor (PDGF) on HSC proliferation and collagen synthesis was not inhibited by fetuin but could be significantly reduced by 70% and 40% respectively, when treated with pentoxifylline. We also investigated the ability of samples obtained from patients with hepatic fibrosis to inhibit HSC apoptosis, as determined by okadaic acid-induced 4-hydroxynonenal immunocytochemistry in HSCs. We have previously reported that okadaic acid induces apoptosis in HSCs as assessed by Hoescht and TUNEL. Okadaic acid treatment produced a positive 4-hydroxynonenal (4-HNE) immunoreactivity in HSCs and treatment with HCV patient MCM or TGFbeta decreased the 4-HNE positive immunoreactivity in HSCs treated with okadaic acid. Our results suggest that fetuin may be beneficial in hepatic fibrosis and suggest that combination of fetuin and pentoxifylline may target the two key events in hepatic fibrosis by modifying the effects of TGFbeta and PDGF, the two major growth factors in fibrosis.

Multiple transforming growth factor-beta isoforms and receptors function during epithelial-mesenchymal cell transformation in the embryonic heart

Epithelial-mesenchymal cell transformation (EMT) is a critical process during development of the heart valves. Transition of endothelial cells into mesenchymal cells in the atrioventricular (AV) canal and the outflow tract regions of the heart form the cardiac cushions that eventually form the heart valves. Collagen gel invasion assay has aided in the identification of molecules that regulate EMT. Among those, transforming growth factor-beta (TGF-beta) ligands and receptors demonstrate a critical role during EMT. In the chick, TGF-beta ligands and some receptors have specific functions during EMT. TGF-beta2 mediates endothelial cell-cell activation and separation, and TGF-beta3 mediates cell invasion into the extracellular matrix. Receptors involved in the EMT process include TGF-beta receptor type II (TBRII), TBRIII, endoglin and the TBRI receptors, ALK2 and ALK5. In contrast, in the mouse model, TGF-beta2 is the only ligand involved in EMT. The TGF-beta2 null mouse has either increased EMT or a mesenchymal cell proliferation after EMT. However, functional studies of TGF-beta1 in vivo and in vitro showed that TGF-beta1 functions in the EMT of the mouse AV canal. Latent TGF-beta-binding protein (LTBP-1) and endoglin have a role in the EMT process. Therefore, TGF-betas mediate cardiac EMT in both embryonic species. Further studies will reveal the identification of ligand and receptor-specific activities.

Large hepatitis delta antigen modulates transforming growth factor-beta signaling cascades: implication of hepatitis delta virus-induced liver fibrosis

BACKGROUND & AIMS

Transforming growth factor-beta (TGF-beta) has been implicated in the pathogenesis of liver disease. TGF-beta is involved in liver regeneration and in the fibrotic and cirrhotic transformation with hepatitis viral infection. Hepatitis delta virus (HDV) infection causes fulminant hepatitis and liver cirrhosis. To elucidate the molecular mechanism of HDV pathogenesis, we examined the effects of HDV-encoded-only protein, the small hepatitis delta antigen (SHDAg), and the large hepatitis delta antigen (LHDAg), on TGF-beta- and c-Jun-induced signaling cascades.

METHODS

The effects of either SHDAg or LHDAg on TGF-beta- and c-Jun-induced signaling cascades in Huh7 and Cos7 cells were investigated by luciferase reporter gene assay, immunoprecipitation assay, electrophoretic mobility shift assay, Western blot analysis, and confocal microscopy analysis.

RESULTS

The LHDAg, but not the SHDAg, potentiated TGF-beta- and c-Jun-induced signal activation, and the isoprenylation of LHDAg played a major role in signaling cascades. LHDAg synergistically activated hepatitis B virus X protein-mediated TGF-beta and AP-1 signaling cascades. In addition, LHDAg enhanced the protein expression level of TGF-beta-induced plasminogen activator inhibitor-1.

CONCLUSIONS

LHDAg may induce liver fibrosis through the regulation of TGF-beta-induced signal transductions. This regulation of TGF-beta-mediated signaling is accomplished by the isoprenylation of LHDAg, which is a novel mechanism involved in HDV pathogenesis.

Large hepatitis delta antigen modulates transforming growth factor-beta signaling cascades: implication of hepatitis delta virus-induced liver fibrosis

BACKGROUND & AIMS

Transforming growth factor-beta (TGF-beta) has been implicated in the pathogenesis of liver disease. TGF-beta is involved in liver regeneration and in the fibrotic and cirrhotic transformation with hepatitis viral infection. Hepatitis delta virus (HDV) infection causes fulminant hepatitis and liver cirrhosis. To elucidate the molecular mechanism of HDV pathogenesis, we examined the effects of HDV-encoded-only protein, the small hepatitis delta antigen (SHDAg), and the large hepatitis delta antigen (LHDAg), on TGF-beta- and c-Jun-induced signaling cascades.

METHODS

The effects of either SHDAg or LHDAg on TGF-beta- and c-Jun-induced signaling cascades in Huh7 and Cos7 cells were investigated by luciferase reporter gene assay, immunoprecipitation assay, electrophoretic mobility shift assay, Western blot analysis, and confocal microscopy analysis.

RESULTS

The LHDAg, but not the SHDAg, potentiated TGF-beta- and c-Jun-induced signal activation, and the isoprenylation of LHDAg played a major role in signaling cascades. LHDAg synergistically activated hepatitis B virus X protein-mediated TGF-beta and AP-1 signaling cascades. In addition, LHDAg enhanced the protein expression level of TGF-beta-induced plasminogen activator inhibitor-1.

CONCLUSIONS

LHDAg may induce liver fibrosis through the regulation of TGF-beta-induced signal transductions. This regulation of TGF-beta-mediated signaling is accomplished by the isoprenylation of LHDAg, which is a novel mechanism involved in HDV pathogenesis.

Soluble betaglycan reduces renal damage progression indb/dbmice

Transforming growth factor-β (TGF-β) is a key mediator in the pathogenesis of renal diseases. Betaglycan, also known as the type III TGF-β receptor, regulates TGF-β action by modulating its access to the type I and II receptors. Betaglycan potentiates TGF-β; however, soluble betaglycan, which is produced by the shedding of the membrane-bound receptor, is a potent antagonist of TGF-β. In the present work, we have used a recombinant form of soluble betaglycan (SBG) to prevent renal damage in genetically obese and diabetic db/db mice. Eight-wk-old db/db or nondiabetic ( db/m) mice were injected intraperitoneally with 50 μg of SBG or vehicle alone three times a wk for 8 wk. The db/db mice that received vehicle presented albuminuria and increased serum creatinine, as well as glomerular mesangial matrix expansion. The db/db mice treated with SBG exhibited a reduction in serum creatinine, albuminuria, and structural renal damage. These effects were associated with lower kidney levels of mRNAs encoding TGF-β1, TGF-β2, TGF-β3, collagen IV, collagen I, fibronectin, and serum glucocorticoid kinase as well as a reduction in the immunostaining of collagen IV and fibronectin. Our data indicate that SBG is a renoprotective agent that neutralized TGF-β actions in this model of nephropathy. Because SBG has a high affinity for all TGF-β isoforms, in particular TGF-β2, it is found naturally in serum and tissues and its shedding may be regulated. We believe that SBG shall prove convenient for long-term treatment of kidney diseases and other pathologies in which TGF-β plays a pathophysiological role.