Evidence for TGF-ß1 and bleomycin intracellular signaling through autocrine regulation of Smad 3 binding to the proximal promoter of theSmad 7 gene

Epigenetic signatures in cardiac fibrosis: Focusing on noncoding RNA regulators as the gatekeepers of cardiac fibroblast identity

Cardiac fibroblasts play a pivotal role in cardiac fibrosis by transformation of fibroblasts into myofibroblasts, which synthesis and secrete a large number of extracellular matrix proteins. Ultimately, this will lead to cardiac wall stiffness and impaired cardiac performance. The epigenetic regulation and fate reprogramming of cardiac fibroblasts has been advanced considerably in recent decades. Non coding RNAs (microRNAs, lncRNAs, circRNAs) regulate the functions and behaviors of cardiac fibroblasts, including proliferation, migration, phenotypic transformation, inflammation, pyroptosis, apoptosis, autophagy, which can provide the basis for novel targeted therapeutic treatments that abrogate activation and inflammation of cardiac fibroblasts, induce different death pathways in cardiac fibroblasts, or make it sensitive to established pathogenic cells targeted cytotoxic agents and biotherapy. This review summarizes our current knowledge in this field of ncRNAs function in epigenetic regulation and fate determination of cardiac fibroblasts as well as the details of signaling pathways contribute to cardiac fibrosis. Moreover, we will comment on the emerging landscape of lncRNAs and circRNAs function in regulating signal transduction pathways, gene translation processes and post-translational regulation of gene expression in cardiac fibroblast. In the end, the prospect of cardiac fibroblasts targeted therapy for cardiac fibrosis based on ncRNAs is discussed.

The role of transforming growth factor beta in thyroid autoimmunity: current knowledge and future perspectives

The complex mechanisms, which are related to the pathophysiology and the development of autoimmune thyroid diseases, involve transforming growth factor beta (TGF-β) and its interplay with the immune system. The aim of this review is to examine the role of TGF-β regarding thyroid autoimmunity and explore the potent role of this molecule either as a diagnostic or prognostic marker or a therapeutic target regarding autoimmune thyroid diseases. TGF-β is clearly a master regulator of the immune response, exerting either inhibitory or facilitatory effects on cells of the immune system. Thus, this molecule is involved in the pathogenesis and development of autoimmune thyroid diseases. Recent research has revealed the involvement of TGF-β in the pathophysiology of autoimmune thyroid diseases. The role of TGF-β in the development of autoimmune thyroid diseases varies, depending on its concentrations, the type of the activated TGF-β signalling pathway, the genetic predisposition of the patient and the pathophysiologic stage of the disease. TGF-β could emerge as a useful diagnostic or prognostic marker for the evolution of thyroid autoimmunity. Promising perspectives for the effective therapeutic use of TGF-β regarding thyroid autoimmunity exist. The main treatment approaches incorporate either enhancement of the immunosuppressive role of TGF-β or inhibition of its facilitatory role in the autoimmune thyroid diseases. Further research towards deeper understanding of TGF-β physiology and clinical application of its possible therapeutic role regarding thyroid autoimmunity is needed.

MiRNA-1202 promotes the TGF-β1-induced proliferation, differentiation and collagen production of cardiac fibroblasts by targeting nNOS

Background

Atrial fibrillation (AF) is a clinically common arrhythmia that affects human health. Myocardial fibrosis serves as an important contributor to AF. Recently, miRNA-1202 have been reported to be up-regulated in AF. However, the role of miRNA-1202 and its mechanism in myocardial fibrosis remain unclear.

Methods

Human cardiac fibroblasts (HCFs) were used to construct a fibrosis model by TGF-β1 induction. The expression of miR-1202 was measured by qRT-PCR. Cell proliferation was assessed by CCK-8 assays. Protein expression levels were measured by western blot. Collagen accumulation was measured by ELISA. The relationship between miR-1202 and nNOS was investigated by luciferase reporter assays.

Results

MiR-1202 expression was obviously increased in HCFs and was both time- and dose-independent. MiR-1202 could increase the proliferation and collagen I, collagen III, and α-SMA levels with or without TGF-β1. MiR-1202 could also increase TGF-β1 and p-Smad2/3 protein levels in comparison to the control group. However, they were obviously decreased after inhibitor transfection. MiR-1202 targets nNOS for negative regulation of HCFs fibrosis by decreasing cell differentiation, collagen deposition and the activity of the TGF-β1/Smad2/3 pathway. Co-transfection of miR-1202 inhibitor and siRNA of nNOS inhibited nNOS protein expression, thereby enhancing the HCFs proliferation. Furthermore, co-transfection of the miR-1202 inhibitor and siRNA of nNOS significantly promoted collagen I, collagen III, TGF-β1, Smad2/3 and α-SMA protein expression and Smad2/3 protein phosphorylation. These findings suggested that miR-1202 promotes HCFs transformation to a pro-fibrotic phenotype by targeting nNOS through activating the TGF-β1/Smad2/3 pathway.

TGF-β Physiology as a Novel Therapeutic Target Regarding Autoimmune Thyroid Diseases: Where Do We Stand and What to Expect

Transforming growth factor beta (TGF-β), as a master regulator of immune response, is deeply implicated in the complex pathophysiology and development of autoimmune thyroid diseases. Based on the close interplay between thyroid autoimmunity and TGF-β, scientific interest was shifted to the understanding of the possible role of this molecule regarding the diagnosis, prognosis, and therapy of these diseases. The main aim of this review is to present research data about possible treatment options based on the role of TGF-β in thyroid autoimmunity. Suggested TGF-β-mediated therapeutic strategies regarding autoimmune thyroid diseases include either the enhancement of its immunosuppressive role or inhibition of its facilitatory role in thyroid autoimmunity. For example, the application of hr-TGF-β can be used to bolster the inhibitory role of TGF-β regarding the development of thyroid diseases, whereas anti-TGF-β antibodies and similar molecules could impede its immune-promoting effects by blocking different levels of TGF-β biosynthesis and activation pathways. In conclusion, TGF-β could evolve to a promising, novel therapeutic tool for thyroid autoimmunity.

Corilagin attenuates aerosol bleomycin-induced experimental lung injury

Idiopathic pulmonary fibrosis (IPF) is a progressing lethal disease with few clinically effective therapies. Corilagin is a tannin derivative which shows anti-inflammatory and antifibrotics properties and is potentiated in treating IPF. Here, we investigated the effect of corilagin on lung injury following bleomycin exposure in an animal model of pulmonary fibrosis. Corilagin abrogated bleomycin-induced lung fibrosis as assessed by H&E; Masson's trichrome staining and lung hydroxyproline content in lung tissue. Corilagin reduced the number of apoptotic lung cells and prevented lung epithelial cells from membrane breakdown, effluence of lamellar bodies and thickening of the respiratory membrane. Bleomycin exposure induced expression of MDA, IKKα, phosphorylated IKKα (p-IKKα), NF-κB P65, TNF-α and IL-1β, and reduced I-κB expression in mice lung tissue or in BALF. These changes were reversed by high-dose corilagin (100 mg/kg i.p) more dramatically than by low dose (10 mg/kg i.p). Last, corilagin inhibits TGF-β1 production and α-SMA expression in lung tissue samples. Taken together, these findings confirmed that corilagin attenuates bleomycin-induced epithelial injury and fibrosis via inactivation of oxidative stress, proinflammatory cytokine release and NF-κB and TGF-β1 signaling. Corilagin may serve as a promising therapeutic agent for pulmonary fibrosis.

Antifibrosis effects of triterpene acids of Eriobotrya japonica (Thunb.) Lindl. leaf in a rat model of bleomycin-induced pulmonary fibrosis

Objective

The aim of this study was to investigate the prophylactic effect and some mechanisms of action of triterpene acids of loquat (TAL) on bleomycin A5-induced pulmonary fibrosis rats.

Methods

A model of pulmonary fibrosis was induced by injecting rats with a single dose of bleomycin A5 (5 mg/kg) into the trachea. From the second day, rats in the preventive groups were treated with TAL (50, 150 or 450 mg/kg) or dexamethasone (1.2 mg/kg). On the 28th day after medication, the rats were killed and haematoxylin-eosin or masson staining was used to evaluate the degree of pulmonary fibrosis. Tumour necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) levels in alveolar macrophage culture supernatant were detected by ELISA. The mRNA expression of TNF-α and TGF-β1 in alveolar macrophage was observed by RT-PCR.

Key findings

Lung histopathological examination showed TAL could ameliorate the structure of the lung and alleviate fibrogenesis. At the same time, TAL (150 or 450 mg/kg dose group) could reduce the expression of TNF-α and TGF-β1 in alveolar macrophage of rats with pulmonary fibrosis at either the protein or mRNA level.

Conclusions

TAL had a positive prophylactic effect on lung fibrosis, which might have been related to its reduction on TNF-α or TGF-β1 expression in the alveolar macrophage of pulmonary fibrosis rats.

Gene expression profiling of human dermal fibroblasts exposed to bleomycin sulphate does not differentiate between radiation sensitive and control patients

Background

Gene expression profiling of the transcriptional response of human dermal fibroblasts to in vitro radiation has shown promise as a predictive test of radiosensitivity. This study tested if treatment with the radiomimetic drug bleomycin sulphate could be used to differentiate radiation sensitive patients and controls in patients who had previously received radiotherapy for early breast cancer.

Findings

Eight patients who developed marked late radiation change assessed by photographic breast appearance and 8 matched patients without any change were selected from women entered in a prospective randomised trial of breast radiotherapy fractionation. Gene expression profiling of primary skin fibroblasts exposed in vitro to bleomycin sulphate and mock treated fibroblast controls was performed. 973 genes were up-regulated and 923 down-reguated in bleomycin sulphate treated compared to mock treated control fibroblasts. Gene ontology analysis revealed enriched groups were cellular localisation, apoptosis, cell cycle and DNA damage response for the deregulated genes. No transcriptional differences were identified between fibroblasts from radiation sensitive cases and control patients; subgroup analysis using cases exhibiting severe radiation sensitivity or with high risk alleles present in TGF β1 also showed no difference.

Conclusions

The transcriptional response of human dermal fibroblasts to bleomycin sulphate has been characterised. No differences between clinically radiation sensitive and control patients were detected using this approach.

COL1A1 oligodeoxynucleotides decoy: biochemical and morphologic effects in an acute wound repair model

Type I collagen is an integral component of granulation tissue and scar, that is highly dependent on TGFβ1, a member of a pro-fibrotic family of cytokines, for its promotion and deposition. Blocking COL1A1 gene transcription obstructs type I collagen synthesis, hindering the progress of granulation tissue deposition and fibrosis. Local injections of a double stranded oligodeoxynucleotide (dsODN) decoy, containing the TGFβ1 regulatory element that is located in the distal promoter of the COL1A1 gene, were investigated in a rat polyvinyl alcohol (PVA) sponge granulation tissue implant model. The effects on the granulation tissue deposition by dsODN decoy therapy were evaluated by the synthesis of types I and III collagens as well as ED-A (cellular) fibronectin. Fluorescently labeled dsODN was used to identify the distribution of the decoy molecules in the sponge implant relative to the observed histological effects. Morphological alterations in cells and changes in the organization of connective tissue were documented and evaluated. Collagen levels were reduced by half in implants treated with 10 nM dsODN decoy compared to scrambled dsODN-treated implants. Histologically, dsODN decoy treated implants had an increased cellular density without a corresponding increase in deposited connective tissue. Polarized light birefringence pattern of Sirius red-stained sections showed less collagen fibers accumulating between fibroblasts. The highest concentration of fluorescently labeled dsODN was identified within the interior margin of sponge implants, correlating to increased cellular density and an altered birefringence patterns. In conclusion, 10 nM dsODN decoy therapy reduced collagen deposition and altered the organization of granulation tissue, supporting its potential as a localized anti-fibrotic therapy for limiting fibrotic conditions.

A CD36 synthetic peptide inhibits silica-induced lung fibrosis in the mice

Silicosis is a kind of pneumoconiosis caused by inhalation of silica dust, which is characterized by lung fibrosis. The biologically active form of transforming growth factor-β1 (TGF-β1) plays a key role in the development of lung fibrosis. CD36 is involved in the transformation of latent TGF-β1 (L-TGF-β1) to active TGF-β1. The antagonistic effect of the synthetic peptide was analyzed by the administration of CD36 (93-110) synthetic peptide to the silicosis model of mice. The hydroxyproline content of the silica + CD36 (93-110) synthetic peptide group was significantly lower than that of the other experimental groups [silica and silica + CD36 (208-225) synthetic peptide groups] (p < .05). Inflammation, fibrotic degree and distribution of collagen fibers in silicotic nodules of the silica + CD36 (93-110) synthetic peptide group were less than those of the other experimental groups. The expressions of collagen I and III of the silica + CD36 (93-110) synthetic peptide group were significantly lower than those of the other experimental groups (p < .05). CD36 (93-110) synthetic peptide reduced the tissue fibrotic pathologies and collagen accumulation in the silicosis model of mice, resulting in the decreased severity of silica-induced lung fibrosis.

Silencing CD36 gene expression results in the inhibition of latent-TGF-beta1 activation and suppression of silica-induced lung fibrosis in the rat

Background

The biologically active form of transforming growth factor-β1 (TGF-β1) plays a key role in the development of lung fibrosis. CD36 is involved in the transformation of latent TGF-β1 (L-TGF-β1) to active TGF-β1. To clarify the role of CD36 in the development of silica-induced lung fibrosis, a rat silicosis model was used to observe both the inhibition of L-TGF-β1 activation and the antifibrotic effect obtained by lentiviral vector silencing of CD36 expression.

Methods

The rat silicosis model was induced by intratracheal injection of 10 mg silica per rat and CD36 expression was silenced by administration of a lentiviral vector (Lv-shCD36). The inhibition of L-TGF-β1 activation was examined using a CCL-64 mink lung epithelial growth inhibition assay, while determination of hydroxyproline content along with pathological and immunohistochemical examinations were used for observation of the inhibition of silica-induced lung fibrosis.

Results

The lentiviral vector (Lv-shCD36) silenced expression of CD36 in alveolar macrophages (AMs) obtained from bronchoalveolar lavage fluid (BALF) and the activation of L-TGF-β1 in the BALF was inhibited by Lv-shCD36. The hydroxyproline content of silica+Lv-shCD36 treated groups was significantly lower than in other experimental groups. The degree of fibrosis in the silica+Lv-shCD36-treated groups was less than observed in other experimental groups. The expression of collagen I and III in the silica+Lv-shCD36-treated group was significantly lower than in the other experimental groups.

Conclusion

These results indicate that silencing expression of CD36 can result in the inhibition of L-TGF-β1 activation in a rat silicosis model, thus further preventing the development of silica-induced lung fibrosis.

A TSP-1 functional fragment inhibits activation of latent transforming growth factor-beta1 derived from rat alveolar macrophage after bleomycin treatment

The antineoplastic antibiotic, bleomycin, is known to induce a well-recognized model of lung fibrosis. Active transforming growth factor-beta1 (TGF-beta1) plays a key role in lung fibrosis induced by bleomycin, TSP-1 (thrombospondin-1) being critical to the activation of L (latent)-TGF-beta1 by virtue of an association of the TSP-1/L-TGF-beta1 complex with CD36, involving the sequence CSVTCG of the TSP-1 functional fragment. To observe the inhibitory effects of TSP-1 functional fragments, critical for CD36 binding, on the activation of L-TGF-beta1, we isolated alveolar macrophages from Wistar rat lungs 7 days after bleomycin administration (5mg/kg body weight) and cultured the cells with or without TSP-1 functional or control fragments. We observed a cell surface association of TGF-beta1 with CD36 by immunofluorescence and quantified the active and total TGF-beta1 by ELISA. The co-localization of CD36 with TGF-beta1, shown by a yellow fluorescence deriving from a mixture of the green and red of the two components, for the TSP-1 functional fragment groups was clearly less than that of the TSP-1 control fragment groups. The quantities and the percentages of active TGF-beta1 in the TSP-1 functional fragment groups were lower than those in the TSP-1 control fragment groups (P<0.05 or P<0.01). These findings suggest that TSP-1 functional fragments could inhibit the activation of L-TGF-beta1 secreted by activated alveolar macrophages through blocking the binding of TSP-1 to CD36.

A TSP-1 synthetic peptide inhibits bleomycin-induced lung fibrosis in mice

Bleomycin showed toxicity to lung and was recognized to induce a well model of lung fibrosis. Activated alveolar macrophages released increased amounts of transforming growth factor-beta1(TGF-beta1) in response to bleomycin-induced lung injury. Thrombospondin-1(TSP-1) was involved in the activation of latent TGF-beta1(L-TGF-beta1) through the association of the TSP-1/L-TGF-beta1 complex with the cell receptor of TSP-1, CD36. The antagonistic effects of the synthetic peptides were studied by the administration of TSP-1 (447-452) synthetic peptides to the mouse model. The hydroxyproline contents of the TSP-1-treated groups were significantly lower than those of other experimental groups. Inflammation, fibrotic degree and distribution of collagen fibers in the interstitial and alveolar in the TSP-1-treated groups were less than those of the other experimental groups. The expressions of collagen I and III in TSP-1-treated groups were significantly lower than in the other experimental groups. TSP-1 synthetic peptide reduced the tissue fibrotic pathologies and collagen accumulation in the model, resulting in the decreased severity of bleomycin-induced lung injury.

Therapies for bleomycin induced lung fibrosis through regulation of TGF-β1 induced collagen gene expression

This review describes normal and abnormal wound healing, the latter characterized by excessive fibrosis and scarring, which for lung can result in morbidity and sometimes mortality. The cells, the extracellular matrix (ECM) proteins, and the growth factors regulating the synthesis, degradation, and deposition of the ECM proteins will be discussed. Therapeutics with particular emphasis given to gene therapies and their effects on specific signaling pathways are described. Bleomycin (BM), a potent antineoplastic antibiotic increases TGF-beta1 transcription, TGF-beta1 gene expression, and TGF-beta protein. Like TGF-beta1, BM acts through the same distal promoter cis-element of the COL1A1 gene causing increased COL1 synthesis and lung fibrosis. Lung fibroblasts exist as subpopulations with one subset predominantly responding to fibrogenic stimuli which could be a specific cell therapeutic target for the onset and development of pulmonary fibrosis.