trichostatin-a and Fibrosis

Rotator cuff (RC) muscle fatty infiltration (FI) is an important factor that determines the clinical outcome of patients with RC repair. There is no effective treatment for RC muscle FI at this time. The goal of this study is to define the role Trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor in regulating muscle fibro/adipogenic progenitors (FAPs) adipogenesis and treating muscle fatty degeneration after massive RC tears in a mouse model. We hypothesize that TSA reduces muscle FI after massive RC tears. HDAC activity was measured in FAPs in RC muscle after tendon/nerve transection or sham surgery. FAPs were treated with TSA for 2 weeks and FAP adipogenesis was evaluated with perilipin and Oil Red O staining, as well as reverse transcript-polymerase chain reaction for adipogenesis-related genes. About 0.5 mg/kg TSA or dimethyl sulfoxide was administered to C57B/L6 mice with massive rotator cuff tears through daily intraperitoneal injection for 6 weeks. Supraspinatus muscles were harvested for biochemical and histology analysis. We found that FAPs showed significantly higher HDAC activity after RC tendon/nerve transection. TSA treatment significantly reduced HDAC activity and inhibited adipogenesis of FAPs. TSA also abolished the role of bone morphogenetic protein-7 in inducing FAP adipogenesis and promoted FAP brown/beige adipose tissue (BAT) differentiation. TSA injection significantly increased histone H3 acetylation and reduced FI of rotator cuff muscles after massive tendon tears. Results from this study showed that TSA can regulate FAP adipogenesis and promote FAP BAT differentiation epigenetically. HDAC inhibition may be a new treatment strategy to reduce muscle FI after RC tears and repair.

Topics: Adipogenesis; Animals; Bone Morphogenetic Protein 7; Cells, Cultured; Drug Evaluation, Preclinical; Female; Fibrosis; Histone Deacetylase Inhibitors; Hydroxamic Acids; Mice, Inbred C57BL; Postoperative Complications; Rotator Cuff Injuries; Stem Cells

Mounting evidence indicates that an increase in histone deacetylation contributes to renal fibrosis. Although inhibition of histone deacetylase (HDAC) can reduce the extent of fibrosis, whether HDAC inhibitors exert the antifibrotic effect through modulating the phenotypes of macrophages, the key regulator of renal fibrosis, remains unknown. Moreover, the functional roles of the M2 macrophage subpopulation in fibrotic kidney diseases remain incompletely understood. Herein, we investigated the role of HDAC inhibitors on renal fibrogenesis and macrophage plasticity. We found that HDAC inhibition by trichostatin A (TSA) reduced the accumulation of interstitial macrophages, suppressed the activation of myofibroblasts and attenuated the extent of fibrosis in obstructive nephropathy. Moreover, TSA inhibited M1 macrophages and augmented M2 macrophage infiltration in fibrotic kidney tissue. Interestingly, TSA preferentially upregulated M2c macrophages and suppressed M2a macrophages in the obstructed kidneys, which was correlated with a reduction of interstitial fibrosis. TSA also repressed the expression of proinflammatory and profibrotic molecules in cultured M2a macrophages and inhibited the activation of renal myofibroblasts. In conclusion, our study was the first to show that HDAC inhibition by TSA alleviates renal fibrosis in obstructed kidneys through facilitating an M1 to M2c macrophage transition.

Topics: Animals; Cell Line; Cells, Cultured; Fibrosis; Histone Deacetylase Inhibitors; Hydroxamic Acids; Macrophages; Male; Mice; Mice, Inbred C57BL; Myofibroblasts; Rats; Renal Insufficiency, Chronic

To investigate whether histone deacetylase (HDAC) activity is associated with postoperative scarring and to evaluate the effect of HDAC inhibition by topical trichostatin A (TSA) on conjunctival fibrosis after trabeculectomy in a rat model.. Trabeculectomy was performed on the left eye of Sprague-Dawley rats. In the first experiment, adenoviruses HDAC 1, HDAC 2, and green fluorescent protein were added to the subconjunctival space during trabeculectomy. Expression of α-smooth muscle actin (α-SMA) was evaluated. In the second experiment, rats undergoing trabeculectomy were randomized into control, vehicle control, steroid, 500 nmol/L TSA, and 1 μmol/L TSA groups. On postoperative day 14, bleb vascularity, toxic effect of topical TSA on corneal epithelium, expression of α-SMA, transforming growth factor (TGF)-β1, and phosphorylated-Smad2/3 and the infiltration of CD45+ cells were determined. Masson's trichrome staining and immunofluorescence staining for α-SMA and CD45 were also performed.. Overexpression of HDAC1 contributed to accelerated conjunctival fibrosis after trabeculectomy. HDAC inhibition by topical administration of 1 μmol/L TSA significantly decreased bleb vascularity, leukocyte infiltration, and expression of α-SMA and TGF-β1 in the conjunctiva. Its effectiveness on conjunctival fibrosis was comparable to that of topical steroid. Masson's trichrome staining showed decreased collagen deposition in the bleb tissues of steroid and 1 μmol/L TSA treatment groups. Topical TSA did not have any toxic effect on the corneal epithelium.. HDAC activity is involved in postoperative conjunctival fibrosis. HDAC inhibition by topical administration of TSA eye drops is a safe and effective therapeutic modality to modulate wound healing after trabeculectomy.

Topics: Actins; Administration, Ophthalmic; Animals; Blotting, Western; Conjunctiva; Disease Models, Animal; Fibrosis; Histone Deacetylase Inhibitors; Hydroxamic Acids; Leukocyte Common Antigens; Phosphorylation; Postoperative Complications; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Smad2 Protein; Smad3 Protein; Trabeculectomy; Transforming Growth Factor beta1

Renal fibrosis is the final common pathological feature in a variety of chronic kidney disease. Trichostatin A (TSA), a histone deacetylase inhibitor, reportedly attenuates renal fibrosis in various kidney disease models. However, the detailed molecular action of TSA in ameliorating renal fibrotic injury is not yet fully understood. In a cultured renal fibroblastic cell model, we showed that TGF-β1 triggers upregulation of α-SMA and fibronectin, two hallmarks of myofibroblastic activation. During the course of TGF-β1 treatment, activation of Smad2/3, p38, ERK, JNK and Notch-2 was also detected. Under the conditions, administration of TSA significantly decreased TGF-β1-stimulated expression of α-SMA, fibronectin, phospho-JNK, and cleaved Notch-2; however, the levels of phospho-Smad2/3, phospho-p38 and phospho-ERK remained unchanged. Pharmacological inhibition of different signaling pathways and genetic knockdown of Notch-2 further revealed JNK as an upstream effector of Notch-2 in TGF-β1-mediated renal fibrosis. Consistently, we also demonstrated that administration of TSA or a γ-secretase inhibitor RO4929097 in the mouse model of unilateral ureteral obstruction significantly ameliorated renal fibrosis through suppression of the JNK/Notch-2 signaling activation. Taken together, our findings provide further insights into the crosstalk among different signaling pathways in renal fibrosis, and elucidate the molecular action of TSA in attenuating fibrogenesis.

Topics: Animals; Benzazepines; Cell Line; Fibroblasts; Fibrosis; Histone Deacetylase Inhibitors; Hydroxamic Acids; Kidney Diseases; Male; MAP Kinase Kinase 4; Mice, Inbred C57BL; Random Allocation; Rats; Receptor, Notch2; Signal Transduction; Smad Proteins; Transforming Growth Factor beta1; Ureteral Obstruction

Systemic sclerosis (SSc) is an autoimmune disease characterized by extensive visceral organ and skin fibrosis. SSc patients have increased production of autoreactive antibodies and Wnt signaling activity. We found that expression of the gene encoding Wnt inhibitor factor 1 (WIF-1) was decreased in fibroblasts from SSc patient biopsies. WIF-1 deficiency in SSc patient cells correlated with increased abundance of the Wnt effector β-catenin and the production of collagen. Knocking down WIF-1 in normal fibroblasts increased Wnt signaling and collagen production. WIF-1 loss and DNA damage were induced in normal fibroblasts by either SSc patient immunoglobulins or oxidative DNA-damaging agents, such as ultraviolet light, hydrogen peroxide, or bleomycin. The DNA damage checkpoint kinase ataxia telangiectasia mutated (ATM) mediated WIF-1 silencing through the phosphorylation of the transcription factor c-Jun, which in turn activated the expression of the gene encoding activating transcription factor 3 (ATF3). ATF3 and c-Jun were recruited together with histone deacetylase 3 (HDAC3) to the WIF-1 promoter and inhibited WIF-1 expression. Preventing the accumulation of reactive oxygen species or inhibiting the activation of ATM, c-Jun, or HDACs restored WIF-1 expression in cultured SSc patient cells. Trichostatin A, an HDAC inhibitor, prevented WIF-1 loss, β-catenin induction, and collagen accumulation in an experimental fibrosis model. Our findings suggest that oxidative DNA damage induced by SSc autoreactive antibodies enables Wnt activation that contributes to fibrosis.

Topics: Adaptor Proteins, Signal Transducing; Antibiotics, Antineoplastic; Ataxia Telangiectasia Mutated Proteins; Biopsy; Bleomycin; Collagen Type I; Collagen Type I, alpha 1 Chain; DNA Damage; DNA Methylation; Fibroblasts; Fibrosis; Gene Silencing; Humans; Hydroxamic Acids; Immunoglobulin G; Oxidative Stress; Oxygen; Protein Synthesis Inhibitors; Reactive Oxygen Species; Repressor Proteins; Scleroderma, Systemic; Signal Transduction; Wnt Proteins

Histone deacetylase (HDAC) inhibitors are promising new compounds for the therapy of fibrotic diseases. In this study we compared the effect of two HDAC inhibitors, trichostatin A and valproic acid, in an experimental model of kidney fibrosis. In mice, doxorubicin (adriamycin) can cause nephropathy characterized by chronic proteinuria, glomerular damage and interstitial inflammation and fibrosis, as seen in human focal segmental glomerulosclerosis. Two treatment regimens were applied, treatment was either started prior to the doxorubicin insult or delayed until a significant degree of proteinuria and fibrosis was present. Pre-treatment of trichostatin A significantly hampered glomerulosclerosis and tubulointerstitial fibrosis, as did the pre-treatment with valproic acid. In contrast, the development of proteinuria was only completely inhibited in the pre-treated valproic acid group, and not in the pre-treated trichostatin A animals. In the postponed treatment with valproic acid, a complete resolution of established doxorubicin-induced proteinuria was achieved within three days, whereas trichostatin A could not correct proteinuria in such a treatment regimen. However, both postponed regimens have comparable efficacy in maintaining the kidney fibrosis to the level reached at the start of the treatments. Moreover, not only the process of fibrosis, but also renal inflammation was attenuated by both HDAC inhibitors. Our data confirm a role for HDACs in renal fibrogenesis and point towards a therapeutic potential for HDAC inhibitors. The effect on renal disease progression and manifestation can however be different for individual HDAC inhibitors.

Topics: Acetylation; Animals; Doxorubicin; Female; Fibrosis; Glomerulosclerosis, Focal Segmental; Histone Deacetylase Inhibitors; Hydroxamic Acids; Immunohistochemistry; Inflammation; Kidney; Kidney Diseases; Mice; Mice, Inbred BALB C; Microscopy, Electron, Transmission; Neutrophil Infiltration; RNA, Messenger; Valproic Acid

Histone deacetylase (HDAC) regulates gene expression by modifying chromatin structure. Although changes in the expression and activities of HDAC may affect the course of kidney disease, the role of HDAC in tubulointerstitial injury has not been explored. We therefore investigated the alterations in HDAC expression and determined the effects of HDAC inhibition on the tubulointerstitial injury induced by unilateral ureteral obstruction. The induction of HDAC1 and HDAC2, accompanied by a decrease in histone acetylation was observed in kidneys injured by ureteral obstruction. Immunohistochemical analysis revealed that HDAC1 and HDAC2 were induced in renal tubular cells. Treatment with an HDAC inhibitor, trichostatin A (TSA), attenuated macrophage infiltration and fibrotic changes in tubulointerstitial injury induced by ureteral obstruction. The induction of colony-stimulating factor-1 (CSF-1), a chemokine known to be involved in macrophage infiltration in tubulointerstitial injury, was reduced in injured kidneys from mice treated with TSA. TSA, valproate, and the knockdown of HDAC1 or HDAC2 significantly reduced CSF-1 induced by TNF-alpha in renal tubular cells. These results suggest that tubular HDAC1 and HDAC2, induced in response to injury, may contribute to the induction of CSF-1 and the initiation of macrophage infiltration and profibrotic responses. These findings suggest a potential of HDAC inhibition therapy aimed at reducing inflammation and fibrosis in tubulointerstitial injury.

Topics: Acetylation; Animals; Disease Models, Animal; Fibrosis; Histone Deacetylase 1; Histone Deacetylase 2; Histone Deacetylase Inhibitors; Histones; Hydroxamic Acids; Kidney Tubules; Macrophage Colony-Stimulating Factor; Male; Mice; Mice, Inbred C57BL; Nephritis, Interstitial; Ureteral Obstruction

Corneal fibroblasts exhibit different phenotypes in different phases of corneal wound healing. In the inflammatory phase, the cells assume a proinflammatory phenotype and produce large amounts of cytokines and chemokines, but in the proliferative and remodeling phases, they adapt a profibrotic state, differentiate into myofibroblasts and increase extracellular matrix protein synthesis, secretion, and deposition. In the present study, the molecular mechanisms regulating the transition of corneal fibroblasts from the proinflammatory state to the profibrotic state were investigated. Corneal fibroblasts were treated with TGFbeta, a known profibrotic and anti-inflammatory factor in wound healing, in the absence or presence of trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor. The results revealed that TGFbeta induced the profibrotic transition of corneal fibroblasts, including increased extracellular matrix synthesis, morphological changes, and assembly of actin filaments. Meanwhile, proinflammatory gene expressions of corneal fibroblasts were down-regulated with the treatment of TGFbeta, as confirmed by cDNA microarray, real time PCR and ELISA. Moreover, TSA reversed the TGFbeta-mediated transition of corneal fibroblasts from the proinflammatory state to the profibrotic state, as accompanied by histone hyperacetylations. In conclusion, TGFbeta suppressed the production of proinflammatory factors and enhanced the expression of matrix remodeling genes of corneal fibroblasts in the transition from the proinflammatory state to the profibrotic state, and the dual roles of TGFbeta on the phenotype regulations of corneal fibroblasts were mediated by altered histone acetylation.

Topics: Acetylation; Actin Cytoskeleton; Cell Shape; Cell Transdifferentiation; Cells, Cultured; Cornea; Enzyme-Linked Immunosorbent Assay; Extracellular Matrix Proteins; Fibroblasts; Fibrosis; Gene Expression Profiling; Gene Expression Regulation; Histone Acetyltransferases; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Inflammation; Inflammation Mediators; Oligonucleotide Array Sequence Analysis; Phenotype; Polymerase Chain Reaction; Transforming Growth Factor beta

Keloids are benign dermal tumors that form during wound healing in genetically susceptible individuals. The mechanism(s) of keloid formation is unknown and there is no satisfactory treatment. We have reported differences between fibroblasts cultured from normal scars and keloids that include a pattern of glucocorticoid resistance and altered regulation of genes in several signaling pathways associated with fibrosis, including Wnt and IGF/IGF-binding protein 5 (IGFBP5). As previously reported for glucocorticoid resistance, decreased expression of the Wnt inhibitor secreted frizzled-related protein 1 (SFRP1), matrix metalloproteinase 3 (MMP3), and dermatopontin (DPT), and increased expression of IGFBP5 and jagged 1 (JAG1) are seen only in fibroblasts cultured from the keloid nodule. In vivo, decreased expression of SFRP1 and SFRP2 and increased expression of IGFBP5 proteins are observed only in proliferative keloid tissue. There is no consistent difference in the replicative life span of normal and keloid fibroblasts, and the altered response to hydrocortisone (HC) and differential regulation of a subset of genes in standard culture medium are maintained throughout at least 80% of the culture lifetime. Preliminary studies using ChIP-chip analysis, Trichostatin A, and 5-aza-2'-deoxycytidine further support an epigenetically altered program in keloid fibroblasts that includes an altered pattern of DNA methylation and histone acetylation.

Topics: Acetylation; Azacitidine; Black or African American; Cell Division; Cells, Cultured; Culture Media; Decitabine; Dermis; DNA Methylation; Enzyme Inhibitors; Epigenesis, Genetic; Fibroblasts; Fibrosis; Gene Expression Profiling; Gene Silencing; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Insulin-Like Growth Factor Binding Protein 5; Intercellular Signaling Peptides and Proteins; Keloid; Membrane Proteins; Oligonucleotide Array Sequence Analysis; Wound Healing

To examine the effects of a histone deacetylase inhibitor, Trichostatin A (TSA), on the behavior of macrophages and subconjunctival fibroblasts in vitro and on ocular surface inflammation and scarring in vivo using an alkali burn wound healing model.. Effects of TSA on expression of inflammation-related growth factors or collagen I were examined by real-time RT-PCR or immunoassay in mouse macrophages or human subconjunctival fibroblasts. Effects of TSA on trans forming growth factor β (TGFβ)/Smad signaling were evaluated with western blotting and/or immunocytochemistry. Alkali-burn injuries on the eyes of mice were performed with three µl of 0.5 N NaOH under general and topical anesthesia. TSA (600 µg/Kg daily) or vehicle was administered to animals via intraperitoneal (i.p.) injection. Histology and real-time RT-PCR investigations evaluated the effects of TSA on the healing process of the cornea.. TSA inhibited TGFβ 1 and vascular endothelial growth factor (VEGF) expression in macrophages, and TGFβ1 and collagen I in ocular fibroblasts. It elevated the expression of 5'-TG-3'-interacting factor (TGIF) and Smad7 in fibroblasts and blocked nuclear translocation of phospho-Smad2. Real-time PCR and immunocytochemistry studies showed that systemic administration of TSA suppressed the inflammation and fibrotic response in the stroma and accelerated epithelial healing in the alkali-burned mouse cornea.. Systemic administration of TSA reduces inflammatory and fibrotic responses in the alkali-burned mouse ocular surface in vivo. The mechanisms of action involve attenuation of Smad signal in mesenchymal cells and reduction in the activation and recruitment of macrophages. TSA has the potential to treat corneal scarring in vivo.

Topics: Animals; Burns, Chemical; Cell Movement; Cell Proliferation; Cells, Cultured; Conjunctiva; Cytokines; Eye Diseases; Fibroblasts; Fibrosis; Gene Expression Regulation; Humans; Hydroxamic Acids; Inflammation; Macrophages; Mice; Neovascularization, Pathologic; Signal Transduction; Transforming Growth Factor beta; Wound Healing

Trichostatin A (TSA), a histone deacetylase inhibitor, has been shown to suppress TGF-beta-induced fibrogenesis in many nonocular tissues. The authors evaluated TSA cytotoxicity and its antifibrogenic activity on TGF-beta-driven fibrosis in the cornea with the use of in vitro and in vivo models.. Human corneal fibroblasts (HSFs) were used for in vitro studies, and New Zealand White rabbits were used for in vivo studies. Haze in the rabbit cornea was produced with photorefractive keratectomy (PRK) using excimer laser. Trypan blue exclusion and MTT assays evaluated TSA cytotoxicity to the cornea. Density of haze in the rabbit eye was graded with slit lamp biomicroscopy. Real-time PCR, immunoblotting, or immunocytochemistry was used to measure alpha-smooth muscle actin (SMA), fibronectin, and collagen type IV mRNA or protein levels. TUNEL assay was used to detect cell death.. TSA concentrations of 250 nM or less were noncytotoxic and did not alter normal HSF morphology or proliferation. TGF-beta1 treatment of HSF significantly increased mRNA and protein levels of SMA (9-fold), fibronectin (2.5-fold), and collagen type IV (2-fold). TSA treatment showed 60% to 75% decreases in TGF-beta1-induced SMA and fibronectin mRNA levels and 1.5- to 3.0-fold decreases in protein levels but had no effect on collagen type IV mRNA or protein levels in vitro. Two-minute topical treatment of TSA on rabbit corneas subjected to -9 D PRK significantly decreased corneal haze in vivo.. TSA inhibits TGF-beta1-induced accumulation of extracellular matrix and myofibroblast formation in the human cornea in vitro and markedly decreases haze in rabbit cornea in vivo.

Topics: Actins; Animals; Cell Proliferation; Cell Survival; Cells, Cultured; Collagen Type IV; Corneal Opacity; Corneal Stroma; Disease Models, Animal; Enzyme Inhibitors; Fibroblasts; Fibronectins; Fibrosis; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Immunoblotting; Immunohistochemistry; In Situ Nick-End Labeling; Photorefractive Keratectomy; Rabbits; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta

Excessive accumulation of extracellular matrix (ECM) in the kidneys and epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells contributes to the renal fibrosis that is associated with diabetic nephropathy. Histone deacetylase (HDAC) determines the acetylation status of histones and thereby controls the regulation of gene expression. This study examined the effect of HDAC inhibition on renal fibrosis induced by diabetes or transforming growth factor (TGF)-beta1 and determined the role of reactive oxygen species (ROS) as mediators of HDAC activation. In streptozotocin (STZ)-induced diabetic kidneys and TGF-beta1-treated normal rat kidney tubular epithelial cells (NRK52-E), we found that trichostatin A, a nonselective HDAC inhibitor, decreased mRNA and protein expressions of ECM components and prevented EMT. Valproic acid and class I-selective HDAC inhibitor SK-7041 also showed similar effects in NRK52-E cells. Among the six HDACs tested (HDAC-1 through -5 and HDAC-8), HDAC-2 activity significantly increased in the kidneys of STZ-induced diabetic rats and db/db mice and TGF-beta1-treated NRK52-E cells. Levels of mRNA expression of fibronectin and alpha-smooth muscle actin were decreased, whereas E-cadherin mRNA was increased when HDAC-2 was knocked down using RNA interference in NRK52-E cells. Interestingly, hydrogen peroxide increased HDAC-2 activity, and the treatment with an antioxidant, N-acetylcysteine, almost completely reduced TGF-beta1-induced activation of HDAC-2. These findings suggest that HDAC-2 plays an important role in the development of ECM accumulation and EMT in diabetic kidney and that ROS mediate TGF-beta1-induced activation of HDAC-2.

Topics: Acetylcysteine; Amides; Animals; Antioxidants; Biphenyl Compounds; Cell Line; Cell Transdifferentiation; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Enzyme Inhibitors; Extracellular Matrix Proteins; Fibrosis; Gene Expression Regulation; Histone Deacetylase 2; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Kidney; Male; Mice; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Recombinant Proteins; Repressor Proteins; RNA Interference; RNA, Messenger; Transforming Growth Factor beta1; Valproic Acid

Activation of renal interstitial fibroblasts is critically involved in the development of tubulointerstitial fibrosis in chronic kidney diseases. In this study, we investigated the effect of trichostatin A (TSA), a specific histone deacetylase (HDAC) inhibitor, on the activation of renal interstitial fibroblasts in a rat renal interstitial fibroblast line (NRK-49F) and the development of renal fibrosis in a murine model of unilateral ureteral obstruction (UUO). alpha-Smooth muscle actin (alpha-SMA) and fibronectin, two hallmarks of fibroblast activation, were highly expressed in cultured NRK-49F cells, and their expression was inhibited in the presence of TSA. Similarly, administration of TSA suppressed the expression of alpha-SMA and fibronectin and attenuated the accumulation of renal interstitial fibroblasts in the kidney after the obstructive injury. Activation of renal interstitial fibroblasts was accompanied by phosphorylation of signal transducer and activator of transcription 3 (STAT3), and TSA treatment also abolished these responses. Furthermore, inhibition of the STAT3 pathway with AG490 inhibited expression of alpha-SMA and fibronectin in NRK-49F cells. Finally, TSA treatment inhibited tubular cell apoptosis and caspase-3 activation in the obstructive kidney. Collectively, we suggest that pharmacological HDAC inhibition may induce antifibrotic activity by inactivation of renal interstitial fibroblasts and inhibition of renal tubular cell death. STAT3 may mediate those actions of HDACs.

Topics: Acetylation; Actins; Animals; Apoptosis; Caspase 3; Cell Line; Enzyme Activation; Fibroblasts; Fibronectins; Fibrosis; Histone Deacetylase Inhibitors; Histone Deacetylases; Hydroxamic Acids; Kidney; Male; Mice; Mice, Inbred C57BL; Phosphorylation; Rats; Renal Insufficiency, Chronic; STAT3 Transcription Factor; Ureteral Obstruction

Fibrosis, a pathological accumulation of collagen in tissues, represents a major global disease burden. Effective characterization of potential antifibrotic drugs has been constrained by poor formation of the extracellular matrix in vitro, due to tardy procollagen processing by collagen C-proteinase/BMP-1, and difficulties in relating this matrix to cell numbers in experimental samples.. The Scar-in-a-Jar model provided, in vitro, the complete biosynthetic cascade of collagen matrix formation including complete conversion of procollagen by C-proteinase/BMP-1, its subsequent extracellular deposition and lysyl oxidase-mediated cross-linking, achieved by applying the biophysical principle of macromolecular 'crowding'. Collagen matrix deposition, velocity and morphology can be controlled using negatively charged 'crowders' in a rapid (2 days) mode or a mixture of neutral 'crowders' in an accelerated (6 days) mode. Combined with quantitative optical bioimaging, this novel system allows for in situ assessment of the area of deposited collagen(s) per cell.. Optical evaluation of known and novel antifibrotic compounds effective at the epigenetic, post-transcriptional/translational/secretional level correlated excellently with corresponding biochemical analyses. Focusing on quantitation of deposited collagen, the Scar-in-a-Jar was most effective in assessing novel inhibitors that may have multiple targets, such as microRNA29c, found to be a promising antifibrotic agent.. This novel screening system supersedes current in vitro fibroplasia models, as a fast, quantitative and non-destructive technique. This method distinguishes a reduction in collagen I deposition, excluding collagen cross-linking, and allows full evaluation of inhibitors of C-proteinase/BMP-1 and other matrix metalloproteinases.

Topics: Cell Line; Cell Proliferation; Collagen Type I; Drug Evaluation, Preclinical; Electrophoresis, Polyacrylamide Gel; Epigenesis, Genetic; Extracellular Matrix; Fibroblasts; Fibrosis; Humans; Hydroxamic Acids; Immunohistochemistry; MicroRNAs; Microscopy, Fluorescence

Topics: Angiotensin II; Animals; Atrial Fibrillation; Cardiomegaly; Connexins; Enzyme Inhibitors; Fibrosis; Gap Junction alpha-5 Protein; Histone Deacetylase Inhibitors; Histone Deacetylases; Homeodomain Proteins; Hydroxamic Acids; Mice; Mice, Transgenic; Time Factors

Atrial fibrosis influences the development of atrial fibrillation (AF), particularly in the setting of structural heart disease where angiotensin-inhibition is partially effective for reducing atrial fibrosis and AF. Histone-deacetylase inhibition reduces cardiac hypertrophy and fibrosis, so we sought to determine if the HDAC inhibitor trichostatin A (TSA) could reduce atrial fibrosis and arrhythmias. Mice over-expressing homeodomain-only protein (HopX(Tg)), which recruits HDAC activity to induce cardiac hypertrophy were investigated in 4 groups (aged 14-18 weeks): wild-type (WT), HopX(Tg), HopX(Tg) mice treated with TSA for 2 weeks (TSA-HopX) and wild-type mice treated with TSA for 2 weeks (TSA-WT). These groups were characterized using invasive electrophysiology, atrial fibrosis measurements, atrial connexin immunocytochemistry and myocardial angiotensin II measurements. Invasive electrophysiologic stimulation, using the same attempts in each group, induced more atrial arrhythmias in HopX(Tg) mice (48 episodes in 13 of 15 HopX(Tg) mice versus 5 episodes in 2 of 15 TSA-HopX mice, P<0.001; versus 9 episodes in 2 of 15 WT mice, P<0.001; versus no episodes in any TSA-WT mice, P<0.001). TSA reduced atrial arrhythmia duration in HopX(Tg) mice (1307+/-289 ms versus 148+/-110 ms, P<0.01) and atrial fibrosis (8.1+/-1.5% versus 3.9+/-0.4%, P<0.001). Atrial connexin40 was lower in HopX(Tg) compared to WT mice, and TSA normalized the expression and size distribution of connexin40 gap junctions. Myocardial angiotensin II levels were similar between WT and HopX(Tg) mice (76.3+/-26.0 versus 69.7+/-16.6 pg/mg protein, P=NS). Therefore, it appears HDAC-inhibition reverses atrial fibrosis, connexin40 remodeling and atrial arrhythmia vulnerability independent of angiotensin II in cardiac hypertrophy.

Topics: Angiotensin II; Animals; Arrhythmias, Cardiac; Cardiomegaly; Connexins; Enzyme Inhibitors; Fibrosis; Gap Junction alpha-5 Protein; Histone Deacetylase Inhibitors; Histone Deacetylases; Homeodomain Proteins; Hydroxamic Acids; Mice; Mice, Transgenic; Time Factors

Tissue fibrosis is a hallmark compromising feature of many disorders. In this study, we investigated the antifibrogenic effects of the histone deacetylase inhibitor trichostatin A (TSA) on cytokine-driven fibrotic responses in vitro and in vivo.. Skin fibroblasts from patients with systemic sclerosis (SSc) and normal healthy control subjects were stimulated with profibrotic cytokines in combination with TSA. Human Colalpha1(I) and fibronectin were measured using real-time polymerase chain reaction, and levels of soluble collagen were estimated using the SirCol collagen assay. Electromobility shift assay and confocal fluorescence microscopy were used to investigate the intracellular distribution of Smad transcription factors. For in vivo analysis, skin fibrosis was quantified by histologic assessment of mouse skin tissue in a model of bleomycin-induced fibrosis.. Reductions in the cytokine-induced transcription of Colalpha1(I) and fibronectin were observed in both normal and SSc skin fibroblasts following the addition of TSA. Similarly, the expression of total collagen protein in TSA-stimulated SSc skin fibroblasts was reduced to basal levels. The mechanism of action of TSA included inhibition of the nuclear translocation and DNA binding of profibrotic Smad transcription factors. Western blot analysis revealed an up-regulation of the cell cycle inhibitor p21 by TSA, leading to reduced proliferation of fibroblasts. In addition, in bleomycin-induced fibrosis in mice, TSA prevented dermal accumulation of extracellular matrix in vivo.. These findings provide novel insights into the epigenetic regulation of fibrosis. TSA and similar inhibitory compounds appear to represent early therapeutic strategies for achieving reversal of the cytokine-driven induction of matrix synthesis that leads to fibrosis.

Topics: Animals; Bleomycin; Cell Survival; Cells, Cultured; Collagen Type I; Collagen Type I, alpha 1 Chain; Cyclin-Dependent Kinase Inhibitor p21; Disease Models, Animal; Drug Combinations; Extracellular Matrix; Fibroblasts; Fibronectins; Fibrosis; Gene Expression; Hydroxamic Acids; Mice; Protein Synthesis Inhibitors; RNA, Messenger; Skin; Smad3 Protein; Transforming Growth Factor beta

Pharmacological interventions that increase myofiber size counter the functional decline of dystrophic muscles. We show that deacetylase inhibitors increase the size of myofibers in dystrophin-deficient (MDX) and alpha-sarcoglycan (alpha-SG)-deficient mice by inducing the expression of the myostatin antagonist follistatin in satellite cells. Deacetylase inhibitor treatment conferred on dystrophic muscles resistance to contraction-coupled degeneration and alleviated both morphological and functional consequences of the primary genetic defect. These results provide a rationale for using deacetylase inhibitors in the pharmacological therapy of muscular dystrophies.

Topics: Animals; Dystrophin; Enzyme Inhibitors; Fibrosis; Follistatin; Hydroxamic Acids; Mice; Mice, Inbred C57BL; Mice, Inbred mdx; Muscles; Muscular Dystrophy, Animal; Phenylbutyrates; Sarcoglycans; Satellite Cells, Skeletal Muscle; Valproic Acid

Radiotherapy is an effective treatment for head and neck, skin, anogenital, and breast cancers. However, radiation-induced skin morbidity limits the therapeutic benefits. A low-toxicity approach to selectively reduce skin morbidity without compromising tumor killing by radiotherapy is needed. We found that the antitumor agents known as histone deacetylase (HDAC) inhibitors (phenylbutyrate, trichostatin A, and valproic acid) could suppress cutaneous radiation syndrome. The effects of HDAC inhibitors in promoting the healing of wounds caused by radiation and in decreasing later skin fibrosis and tumorigenesis were correlated with suppression of the aberrant expression of radiation-induced transforming growth factor beta and tumor necrosis factor alpha. Our findings implicate that the inhibition of HDAC may provide a novel strategy to increase the therapeutic gain in cancer radiotherapy by not only inhibiting tumor growth but also protecting normal tissues.

Topics: Acetylation; Animals; Antineoplastic Agents; Blotting, Northern; Blotting, Western; Cell Line, Tumor; Enzyme Inhibitors; Female; Fibrosis; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Immunohistochemistry; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Neoplasms; Phenylbutyrates; Radiation Injuries; Radiotherapy; Rats; Rats, Sprague-Dawley; Ribonucleases; Skin; Time Factors; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Valproic Acid; Wound Healing

Excessive production of collagens by alpha-smooth muscle actin (alpha-SMA)-positive myofibroblasts leads to fibrotic skin diseases, such as hypertrophic scarring. This process is characterized by an imbalance between extracellular matrix (ECM) synthesis and degradation, while transforming growth factor beta (TGF-beta(1)), known to be a key mediator of fibrogenesis, is up-regulated. In this study we have investigated the possible antifibrogenic effect of Trichostatin A (TSA), a histone deacetylase inhibitor, on rat skin fibroblasts in culture. mRNA steady-state levels and de novo protein synthesis of procollagen types I and III and alpha-SMA were inhibited when skin fibroblasts were treated with 100 nM TSA with or without TGF-beta(1). While the transcription rate of the procollagen alpha1(I) gene was increased following TSA or TGF-beta(1) treatment, TSA abrogated the stimulatory effect of TGF-beta(1) on procollagen alpha1(I) transcription when both compounds were added simultaneously. The reduction of procollagen alpha1(I) and alpha1(III) mRNA steady-state levels by TSA did not require de novo protein synthesis, while the effect of TSA on alpha-SMA mRNA steady-state levels was cycloheximide-sensitive. Interestingly, TSA affected TGF-beta(1) and its downstream mediators, i.e., the Smad family proteins. TSA strongly induced in a biphasic way the expression of 5'TG3' interacting factor (TGIF), a known endogenous corepressor molecule of the TGF-beta(1) signaling pathway. Addition of exogenous TGF-beta(1) did not interfere with the effect of TSA on the TGIF mRNA level. Our study shows that inhibition of histone deacetylases by TSA reduces expression of fibrosis-related genes in skin fibroblasts and this coincides by alterations in the TGF-beta(1) signaling pathway.

Topics: Animals; Collagen; Drug Antagonism; Extracellular Matrix; Fibroblasts; Fibrosis; Histone Deacetylase Inhibitors; Hydroxamic Acids; Male; Protein Synthesis Inhibitors; Rats; Rats, Wistar; Skin; Transforming Growth Factor beta; Transforming Growth Factor beta1