p300 is elevated in systemic sclerosis and its expression is positively regulated by TGF-β: epigenetic feed-forward amplification of fibrosis

Epigenetic Control of Redox Pathways in Cancer Progression

Significance: Growing evidence indicates the importance of redox reactions homeostasis, mediated predominantly by reactive oxygen species (ROS) in influencing the development, differentiation, progression, metastasis, programmed cell death, tumor microenvironment, and therapeutic resistance of cancer. Therefore, reviewing the ROS-linked epigenetic changes in cancer is fundamental to understanding the progression and prevention of cancer. Recent Advances: We review in depth the molecular mechanisms involved in ROS-mediated epigenetic changes that lead to alteration of gene expression by altering DNA, modifying histones, and remodeling chromatin and noncoding RNA. Critical Issues: In cancerous cells, alterations of the gene-expression regulatory elements could be generated by the virtue of imbalance in tumor microenvironment. Various oxidizing agents and mitochondrial electron transport chain are the major pathways that generate ROS. ROS plays a key role in carcinogenesis by activating pro-inflammatory signaling pathways and DNA damage. This loss of ROS-mediated epigenetic regulation of the signaling pathways may promote tumorigenesis. We address all such aspects in this review. Future Directions: Developments in this growing field of epigenetics are expected to contribute to further our understanding of human health and diseases such as cancer and to test the clinical applications of redox-based therapy. Recent studies of the cancer-epigenetic landscape have revealed pervasive deregulation of the epigenetic factors in cancer. Thus, the study of interaction between ROS and epigenetic factors in cancer holds a great promise in the development of effective and targeted treatment modalities. Antioxid. Redox Signal. 00, 000-000.

Structure, unique biological properties, and mechanisms of action of transforming growth factor β

Transforming growth factor β (TGF-β) is a ubiquitous molecule that is extremely conserved structurally and plays a systemic role in human organism. TGF-β is a homodimeric molecule consisting of two subunits joined through a disulphide bond. In mammals, three genes code for TGF-β1, TGF-β2, and TGF-β3 isoforms of this cytokine with a dominating expression of TGF-β1. Virtually, all normal cells contain TGF-β and its specific receptors. Considering the exceptional role of fine balance played by the TGF-β in anumber of physiological and pathological processes in human body, this cytokine may be proposed for use in medicine as an immunosuppressant in transplantology, wound healing and bone repair. TGFb itself is an important target in oncology. Strategies for blocking members of TGF-β signaling pathway as therapeutic targets have been considered. In this review, signalling mechanisms of TGF-β1 action are addressed, and their role in physiology and pathology with main focus on carcinogenesis are described.

Fibroblast and myofibroblast activation in normal tissue repair and fibrosis

The term 'fibroblast' often serves as a catch-all for a diverse array of mesenchymal cells, including perivascular cells, stromal progenitor cells and bona fide fibroblasts. Although phenotypically similar, these subpopulations are functionally distinct, maintaining tissue integrity and serving as local progenitor reservoirs. In response to tissue injury, these cells undergo a dynamic fibroblast-myofibroblast transition, marked by extracellular matrix secretion and contraction of actomyosin-based stress fibres. Importantly, whereas transient activation into myofibroblasts aids in tissue repair, persistent activation triggers pathological fibrosis. In this Review, we discuss the roles of mechanical cues, such as tissue stiffness and strain, alongside cell signalling pathways and extracellular matrix ligands in modulating myofibroblast activation and survival. We also highlight the role of epigenetic modifications and myofibroblast memory in physiological and pathological processes. Finally, we discuss potential strategies for therapeutically interfering with these factors and the associated signal transduction pathways to improve the outcome of dysregulated healing.

Lysine acetyltransferase 14 mediates TGF-β-induced fibrosis in ovarian endometrioma via co-operation with serum response factor

BACKGROUND

Fibrogenesis within ovarian endometrioma (endometrioma), mainly induced by transforming growth factor-β (TGF-β), is characterized by myofibroblast over-activation and excessive extracellular matrix (ECM) deposition, contributing to endometrioma-associated symptoms such as infertility by impairing ovarian reserve and oocyte quality. However, the precise molecular mechanisms that underpin the endometrioma- associated fibrosis progression induced by TGF-β remain poorly understood.

METHODS

The expression level of lysine acetyltransferase 14 (KAT14) was validated in endometrium biopsies from patients with endometrioma and healthy controls, and the transcription level of KAT14 was further confirmed by analyzing a published single-cell transcriptome (scRNA-seq) dataset of endometriosis. We used overexpression, knockout, and knockdown approaches in immortalized human endometrial stromal cells (HESCs) or human primary ectopic endometrial stromal cells (EcESCs) to determine the role of KAT14 in TGF-β-induced fibrosis. Furthermore, an adeno-associated virus (AAV) carrying KAT14-shRNA was used in an endometriosis mice model to assess the role of KAT14 in vivo.

RESULTS

KAT14 was upregulated in ectopic lesions from endometrioma patients and predominantly expressed in activated fibroblasts. In vitro studies showed that KAT14 overexpression significantly promoted a TGF-β-induced profibrotic response in endometrial stromal cells, while KAT14 silencing showed adverse effects that could be rescued by KAT14 re-enhancement. In vivo, Kat14 knockdown ameliorated fibrosis in the ectopic lesions of the endometriosis mouse model. Mechanistically, we showed that KAT14 directly interacted with serum response factor (SRF) to promote the expression of α-smooth muscle actin (α-SMA) by increasing histone H4 acetylation at promoter regions; this is necessary for TGF-β-induced ECM production and myofibroblast differentiation. In addition, the knockdown or pharmacological inhibition of SRF significantly attenuated KAT14-mediating profibrotic effects under TGF-β treatment. Notably, the KAT14/SRF complex was abundant in endometrioma samples and positively correlated with α-SMA expression, further supporting the key role of KAT14/SRF complex in the progression of endometrioma-associated fibrogenesis.

CONCLUSION

Our results shed light on KAT14 as a key effector of TGF-β-induced ECM production and myofibroblast differentiation in EcESCs by promoting histone H4 acetylation via co-operating with SRF, representing a potential therapeutic target for endometrioma-associated fibrosis.

Single-cell epigenomic dysregulation of Systemic Sclerosis fibroblasts via CREB1/EGR1 axis in self-assembled human skin equivalents

Systemic sclerosis (SSc) is an autoimmune disease characterized by skin fibrosis, internal organ involvement and vascular dropout. We previously developed and phenotypically characterized an in vitro 3D skin-like tissue model of SSc, and now analyze the transcriptomic (scRNA-seq) and epigenetic (scATAC-seq) characteristics of this model at single-cell resolution. SSc 3D skin-like tissues were fabricated using autologous fibroblasts, macrophages, and plasma from SSc patients or healthy control (HC) donors. SSc tissues displayed increased dermal thickness and contractility, as well as increased α-SMA staining. Single-cell transcriptomic and epigenomic analyses identified keratinocytes, macrophages, and five populations of fibroblasts (labeled FB1 - 5). Notably, FB1 APOE-expressing fibroblasts were 12-fold enriched in SSc tissues and were characterized by high EGR1 motif accessibility. Pseudotime analysis suggests that FB1 fibroblasts differentiate from a TGF-β1-responsive fibroblast population and ligand-receptor analysis indicates that the FB1 fibroblasts are active in macrophage crosstalk via soluble ligands including FGF2 and APP. These findings provide characterization of the 3D skin-like model at single cell resolution and establish that it recapitulates subsets of fibroblasts and macrophage phenotypes observed in skin biopsies.

Recent Insights into the Role of DNA Methylation and Histone Modifications in Systemic Sclerosis: A Scoping Review

Systemic sclerosis is a complex idiopathic disease originating from an intricate interplay between genetic susceptibility, environmental factors, and epigenetic modifications. This scoping review aims to map the advancements made regarding DNA methylation abnormalities and histone modifications in systemic sclerosis in the past decade. A literature search was conducted using three electronic databases (Scopus, Web of Science and PubMed) to identify relevant articles. A total of 44 studies were selected for this review, demonstrating the critical contribution of epigenetic perturbations in multiple cell types to disease pathogenesis. In conclusion, this scoping review has elucidated the significant discoveries made in the past decade regarding the role of DNA methylation and histone modifications in systemic sclerosis. Further progress in the field could lead to the development of novel treatment possibilities targeting epigenetic marks.

Epigenetic mechanisms driving the pathogenesis of systemic lupus erythematosus, systemic sclerosis and dermatomyositis

Autoimmune connective tissue disorders, including systemic lupus erythematosus, systemic sclerosis (SSc) and dermatomyositis (DM), often manifest with debilitating cutaneous lesions and can result in systemic organ damage that may be life-threatening. Despite recent therapeutic advancements, many patients still experience low rates of sustained remission and significant treatment toxicity. While genetic predisposition plays a role in these connective tissue disorders, the relatively low concordance rates among monozygotic twins (ranging from approximately 4% for SSc to about 11%-50% for SLE) have prompted increased scrutiny of the epigenetic factors contributing to these diseases. In this review, we explore some seminal studies and key findings to provide a comprehensive understanding of how dysregulated epigenetic mechanisms can contribute to the development of SLE, SSc and DM.

Involvement of plasminogen activator inhibitor-1 in p300/p53-mediated age-related atrial fibrosis

Plasminogen activator inhibitor-1 (PAI-1), a key regulator of the fibrinolytic system, is also intimately involved in the fibrosis. Although PAI-1 may be involved in the occurrence of atrial fibrillation (AF) and thrombosis in the elderly, but whether it participated in aging-related atrial fibrosis and the detailed mechanism is still unclear. We compared the transcriptomics data of young (passage 4) versus senescent (passage 14) human atrial fibroblasts and found that PAI-1 was closely related to aging-related fibrosis. Aged mice and senescent human and mouse atrial fibroblasts underwent electrophysiological and biochemical studies. We found that p300, p53, and PAI-1 protein expressions were increased in the atrial tissue of aged mice and senescent human and mouse atrial fibroblasts. Curcumin or C646 (p300 inhibitor), or p300 knockdown inhibited the expression of PAI-1 contributing to reduced atrial fibroblasts senescence, atrial fibrosis, and the AF inducibility. Furthermore, p53 knockdown decreased the protein expression of PAI-1 and p21 in senescent human and mouse atrial fibroblasts. Our results suggest that p300/p53/PAI-1 signaling pathway participates in the mechanism of atrial fibrosis induced by aging, which provides new sights into the treatment of elderly AF.

Expression of collagen-related piRNA is dysregulated in cultured dermal fibroblasts derived from patients with scleroderma

PIWI-interacting RNA (piRNA) is a class of recently discovered small non-coding RNAs. piRNAs derive from an initial transcript encompassing a piRNA cluster via a unique biosynthesis process, interact with PIWI proteins, bind to specific targets, and recruit chromatin modifiers to enable transcriptional repression. Abnormal expression of PIWI proteins and piRNAs has been reported in some human cancers, with participation of some PIWI/piRNAs complexes in tumorigenesis and association with cancer prognosis. Their expression in patients with systemic sclerosis (SSc) has not been widely elucidated. PIWI/piRNAs and their role in the pathogenesis of collagen accumulation in SSc was therefore investigated; no difference was found in the PIWIL1-4 levels between normal and cultured SSc dermal fibroblasts. Among piRNAs predicted to target SSc-related molecules, we first found significant piR-32364 up-regulation in SSc dermal fibroblasts, likely due to intrinsic TGF-β signaling. Forced piR-32364 overexpression in normal fibroblasts significantly reduced COL1A1 expression both at mRNA and protein levels, but not COL1A2. Thus, piR-32364 overexpression in SSc fibroblasts may be the negative feedback against collagen up-regulation, which could suggest the potential of piRNAs as a therapeutic target.

Iguratimod attenuated fibrosis in systemic sclerosis via targeting early growth response 1 expression

BACKGROUND

The early growth response 1 (EGR1) is a central transcription factor involved in systemic sclerosis (SSc) pathogenesis. Iguratimod is a synthesized anti-rheumatic disease-modifying drug, which shows drastic inhibition to EGR1 expression in B cells. This study is aiming to investigate the anti-fibrotic effect of iguratimod in SSc.

METHODS

EGR1 was detected by immunofluorescence staining real-time PCR or western blot. Iguratimod was applied in EGR1 overexpressed or knockdown human dermal fibroblast, bleomycin pre-treated mice, tight skin 1 mice, and SSc skin xenografts. RNA sequencing was performed in cultured fibroblast and xenografts to identify the iguratimod regulated genes.

RESULTS

EGR1 overexpressed predominantly in non-immune cells of SSc patients. Iguratimod reduced EGR1 expression in fibroblasts and neutralized changes of EGR1 response genes regulated by TGFβ. The extracellular matrix (ECM) production and activation of fibroblasts were attenuated by iguratimod while EGR1 overexpression reversed this effect of iguratimod. Iguratimod ameliorated the skin fibrosis induced by bleomycin and hypodermal fibrosis in TSK-1 mice. Decreasing in the collagen content as well as the density of EGR1 or TGFβ positive fibroblasts of skin xenografts from naïve SSc patients was observed after local treatment of iguratimod.

CONCLUSION

Targeting EGR1 expression is a probable underlying mechanism for the anti-fibrotic effect of iguratimod.

EP300 as a Molecular Integrator of Fibrotic Transcriptional Programs

Fibrosis is a condition characterized by the excessive accumulation of extracellular matrix proteins in tissues, leading to organ dysfunction and failure. Recent studies have identified EP300, a histone acetyltransferase, as a crucial regulator of the epigenetic changes that contribute to fibrosis. In fact, EP300-mediated acetylation of histones alters global chromatin structure and gene expression, promoting the development and progression of fibrosis. Here, we review the role of EP300-mediated epigenetic regulation in multi-organ fibrosis and its potential as a therapeutic target. We discuss the preclinical evidence that suggests that EP300 inhibition can attenuate fibrosis-related molecular processes, including extracellular matrix deposition, inflammation, and epithelial-to-mesenchymal transition. We also highlight the contributions of small molecule inhibitors and gene therapy approaches targeting EP300 as novel therapies against fibrosis.

The deubiquitinase UCHL3 mediates p300-dependent chemokine signaling in alveolar type II cells to promote pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, fatal, fibrotic, interstitial lung disease of unknown cause. Despite extensive studies, the underlying mechanisms of IPF development remain unknown. Here, we found that p300 was upregulated in multiple epithelial cells in lung samples from patients with IPF and mouse models of lung fibrosis. Lung fibrosis was significantly diminished by the alveolar type II (ATII) cell-specific deletion of the p300 gene. Moreover, we found that ubiquitin C-terminal hydrolase L3 (UCHL3)-mediated deubiquitination of p300 led to the transcriptional activation of the chemokines Ccl2, Ccl7, and Ccl12 through the cooperative action of p300 and C/EBPβ, which consequently promoted M2 macrophage polarization. Selective blockade of p300 activity in ATII cells resulted in the reprogramming of M2 macrophages into antifibrotic macrophages. These findings demonstrate a pivotal role for p300 in the development of lung fibrosis and suggest that p300 could serve as a promising target for IPF treatment.

Epigenetics as a versatile regulator of fibrosis

Fibrosis, a process caused by excessive deposition of extracellular matrix (ECM), is a common cause and outcome of organ failure and even death. Researchers have made many efforts to understand the mechanism of fibrogenesis and to develop therapeutic strategies; yet, the outcome remains unsatisfactory. In recent years, advances in epigenetics, including chromatin remodeling, histone modification, DNA methylation, and noncoding RNA (ncRNA), have provided more insights into the fibrotic process and have suggested the possibility of novel therapy for organ fibrosis. In this review, we summarize the current research on the epigenetic mechanisms involved in organ fibrosis and their possible clinical applications.

Histone modification of endothelial-mesenchymal transition in cardiovascular diseases

Endothelial-mesenchymal transition (EndMT) is a differentiation process in which endothelial cells lose their own characteristics and acquire mesenchymal-like characteristics, which contributes to the formation and development of atherosclerotic plaques. Until now, there is still a lack of effective measures to treat atherosclerosis (AS), so there is an urgent need to understand the underlying mechanisms of AS. In addition, although various studies have shown that EndMT is involved in the pathological stages of cardiovascular diseases, such as myocardial fibrosis, myocardial hypertrophy, and hypertension, the specific molecular mechanisms driving EndMT are still in the exploratory stage. In this review, we review the role of histone modifications (methylation, demethylation and acetylation, deacetylation) on EndMT in cardiovascular disease, aiming to target histone-modifying enzymes to guide cardiovascular disease therapy.

Animal Models of Systemic Sclerosis: Using Nailfold Capillaroscopy as a Potential Tool to Evaluate Microcirculation and Microangiopathy: A Narrative Review

Systemic sclerosis (SSc) is an autoimmune disease with three pathogenic hallmarks, i.e., inflammation, vasculopathy, and fibrosis. A wide plethora of animal models have been developed to address the complex pathophysiology and for the development of possible anti-fibrotic treatments. However, no current model comprises all three pathological mechanisms of the disease. To highlight the lack of a complete model, a review of some of the most widely used animal models for SSc was performed. In addition, to date, no model has accomplished the recreation of primary or secondary Raynaud’s phenomenon, a key feature in SSc. In humans, nailfold capillaroscopy (NFC) has been used to evaluate secondary Raynaud’s phenomenon and microvasculature changes in SSc. Being a non-invasive technique, it is widely used both in clinical studies and as a tool for clinical evaluation. Because of this, its potential use in animal models has been neglected. We evaluated NFC in guinea pigs to investigate the possibility of applying this technique to study microcirculation in the nailfold of animal models and in the future, development of an animal model for Raynaud’s phenomenon. The applications are not only to elucidate the pathophysiological mechanisms of vasculopathy but can also be used in the development of novel treatment options.

Histone Acetylation and Modifiers in Renal Fibrosis

Histones are the most abundant proteins bound to DNA in eukaryotic cells and frequently subjected to post-modifications such as acetylation, methylation, phosphorylation and ubiquitination. Many studies have shown that histone modifications, especially histone acetylation, play an important role in the development and progression of renal fibrosis. Histone acetylation is regulated by three families of proteins, including histone acetyltransferases (HATs), histone deacetylases (HDACs) and bromodomain and extraterminal (BET) proteins. These acetylation modifiers are involved in a variety of pathophysiological processes leading to the development of renal fibrosis, including partial epithelial-mesenchymal transition, renal fibroblast activation, inflammatory response, and the expression of pro-fibrosis factors. In this review, we summarize the role and regulatory mechanisms of HATs, HDACs and BET proteins in renal fibrosis and provide evidence for targeting these modifiers to treat various chronic fibrotic kidney diseases in animal models.

Myeloid Fbxw7 Prevents Pulmonary Fibrosis by Suppressing TGF-β Production

Idiopathic pulmonary fibrosis (IPF) is a group of chronic interstitial pulmonary diseases characterized by an inexorable decline in lung function with limited treatment options. The abnormal expression of transforming growth factor-β (TGF-β) in profibrotic macrophages is linked to severe pulmonary fibrosis, but the regulation mechanisms of TGF-β expression are incompletely understood. We found that decreased expression of E3 ubiquitin ligase Fbxw7 in peripheral blood mononuclear cells (PBMCs) was significantly related to the severity of pulmonary fibrosis in IPF patients. Fbxw7 is identified to be a crucial suppressing factor for pulmonary fibrosis development and progression in a mouse model induced by intratracheal bleomycin treatment. Myeloid cell-specific Fbxw7 deletion increases pulmonary monocyte-macrophages accumulation in lung tissue, and eventually promotes bleomycin-induced collagen deposition and progressive pulmonary fibrosis. Notably, the expression of TGF-β in profibrotic macrophages was significantly upregulated in myeloid cell-specific Fbxw7 deletion mice after bleomycin treatment. C-Jun has long been regarded as a critical transcription factor of Tgfb1, we clarified that Fbxw7 inhibits the expression of TGF-β in profibrotic macrophages by interacting with c-Jun and mediating its K48-linked ubiquitination and degradation. These findings provide insight into the role of Fbxw7 in the regulation of macrophages during the pathogenesis of pulmonary fibrosis.

Advances in epigenetics in systemic sclerosis: molecular mechanisms and therapeutic potential

Systemic sclerosis (SSc) is a prototypical inflammatory fibrotic disease involving inflammation, vascular abnormalities and fibrosis that primarily affect the skin and lungs. The aetiology of SSc is unknown and its pathogenesis is only partially understood. Of all the rheumatic diseases, SSc carries the highest all-cause mortality rate and represents an unmet medical need. A growing body of evidence implicates epigenetic aberrations in this intractable disease, including specific modifications affecting the three main cell types involved in SSc pathogenesis: immune cells, endothelial cells and fibroblasts. In this Review, we discuss the latest insights into the role of DNA methylation, histone modifications and non-coding RNAs in SSc and how these epigenetic alterations affect disease features. In particular, histone modifications have a role in the regulation of gene expression pertinent to activation of fibroblasts to myofibroblasts, governing their fate. DNA methyltransferases are crucial in disease pathogenesis by mediating methylation of DNA in specific promoters, regulating expression of specific pathways. We discuss targeting of these enzymes for therapeutic gain. Innovative epigenetic therapy could be targeted to treat the disease in a precision epigenetics approach.

Myofibroblast fate plasticity in tissue repair and fibrosis: Deactivation, apoptosis, senescence and reprogramming

In response to tissue injury, fibroblasts differentiate into professional repair cells called myofibroblasts, which orchestrate many aspects of the normal tissue repair programme including synthesis, deposition and contraction of extracellular matrix proteins, leading to wound closure. Successful tissue repair responses involve termination of myofibroblast activities in order to prevent pathologic fibrotic scarring. Here, we discuss the cellular and molecular mechanisms limiting myofibroblast activities during physiological tissue repair, including myofibroblast deactivation, apoptosis, reprogramming and immune clearance of senescent myofibroblasts. In addition, we summarize pathological mechanisms leading to myofibroblast persistence and survival, a hallmark of fibrotic diseases. Finally, we discuss emerging anti-fibrotic therapies aimed at targeting myofibroblast fate such as senolytics, gene therapy, cellular immunotherapy and CAR-T cells.

Field-based rational design of p300 histone acetyltransferase inhibitor and systematic evaluation as an anti-fibrotic agent

(E)-3-(3-(4-((3-Carbamoylbenzyl)oxy)-3-iodo-5-methoxyphenyl) acryloyl)benzamide (A6) was found to be a potent p300 inhibitor (IC50 = 870 nM) showing a similar binding mode to that of acetyl-CoA, a p300 substrate, and effective anti-fibrotic activity in both TGF-β1-stimulated lung fibroblast cells and bleomycin-induced in vivo lung fibrosis mice.

The Role of Pro-fibrotic Myofibroblasts in Systemic Sclerosis: from Origin to Therapeutic Targeting

Systemic sclerosis (SSc, scleroderma) is a complex connective tissue disorder characterized by multisystem clinical manifestations resulting from immune dysregulation/autoimmunity, vasculopathy and, most notably, progressive fibrosis of the skin and internal organs. In recent years, it has emerged that the main drivers of SSc-related tissue fibrosis are myofibroblasts, a type of mesenchymal cells with both the extracellular matrix-synthesizing features of fibroblasts and the cytoskeletal characteristics of contractile smooth muscle cells. The accumulation and persistent activation of pro-fibrotic myofibroblasts during SSc development and progression result into elevated mechanical stress and reduced matrix plasticity within the affected tissues and may be ascribed to a reduced susceptibility of these cells to pro-apoptotic stimuli, as well as their increased formation from tissue-resident fibroblasts or transition from different cell types. Given the crucial role of myofibroblasts in SSc pathogenesis, finding the way to inhibit myofibroblast differentiation and accumulation by targeting their formation, function and survival may represent an effective approach to hamper the fibrotic process or even halt or reverse established fibrosis. In this review, we discuss the role of myofibroblasts in SSc-related fibrosis, with a special focus on their cellular origin and the signaling pathways implicated in their formation and persistent activation. Furthermore, we provide an overview of potential therapeutic strategies targeting myofibroblasts that may be able to counteract fibrosis in this pathological condition.

Epigenetic Histone Modifications in the Pathogenesis of Diabetic Kidney Disease

Diabetic kidney disease (DKD), as the main complication of diabetes mellitus, is the primary cause of the end-stage renal disease (ESRD) and the most common chronic kidney disease. Overall, 30-40% of patients with type 1 and type 2 diabetes eventually develop DKD. Although some diabetes patients have intensified glycemic control, they still develop diabetic kidney disease. Current treatment methods can alleviate but do not markedly halt disease development, resulting in renal failure and severe complications, even contributing to elevated morbidity and mortality rates. DKD is a disease with interactions of genes and the environment. Emerging evidence indicates that DKD-associated key genes are also regulated by the epigenetic mechanism. Recently, increasing researches involving cells and experimental animals demonstrated that histone post-translational modifications can mediate gene expression, which correlated with diabetic kidney disease. Novel therapeutic strategies for epigenetic events could be beneficial for the early detection and treatment of DKD to prevent it from developing into end-stage renal disease (ESRD). In this review, we discuss prior findings in the field of histone modifications in DKD, especially histone acetylation and histone methylation. We then focus on recent developments in histone acetylation and methylation involved in the pathogenesis of DKD.

Cellular and molecular mechanisms in fibrosis

The activation of fibroblasts is required for physiological tissue remodelling such as wound healing. However, when the regulatory mechanisms are disrupted and fibroblasts remain persistently activated, the progressive deposition of extracellular matrix proteins leads to tissue fibrosis, which results in dysfunction or even loss of function of the affected organ. Although fibrosis has been recognized as a major cause of morbidity and mortality in modern societies, there are only few treatment options available that directly disrupt the release of extracellular matrix from fibroblasts. Intensive research in recent years, however, identified several pathways as core fibrotic mechanisms that are shared across different fibrotic diseases and organs. We discuss herein selection of those core pathways, especially downstream of the profibrotic TGF-β pathway, which are druggable and which may be transferable from bench to bedside.

Pharmacological activation of PPAR-γ: a potential therapy for skin fibrosis

Skin fibrosis caused by excessive collagen synthesis and deposition in the dermis affects the quality of daily life of hundreds of thousands of people around the world. The skin quality, including its smoothness in young age and wrinkly during the aging process, depends largely on the levels of extracellular matrix proteins such as collagen in skin. As physiological levels of collagen are desirable for skin homeostasis, beauty, and its flexibility, too much collagen deposition in the skin is associated with tight hard skin, loss of adipose layer, and flexibility, the pathological manifestations of skin fibrosis in fibrotic diseases such as scleroderma. To understand the molecular basis of skin fibrosis and in search of its therapy, different cellular, molecular, epigenetic, and preclinical studies have been undertaken to control abnormal excessive synthesis and accumulation of matrix protein collagen. Over the last two decades, numerous phase 1 through 3 clinical trials have been conducted to test the safety and efficacy of a wide variety of compounds in amelioration of skin fibrosis and other pathologies in scleroderma, yet, no effective therapy for skin fibrosis is available. This article solely focuses on the role of a nuclear receptor and transcription factor, peroxisome proliferator-activated receptor-gamma (PPAR-γ), as an anti-skin fibrotic driving force and the potential therapeutic efficacies of PPAR-γ-specific ligands/agonists including antidiabetic drugs and other natural or semi-synthetic compounds derived from cannabis in amelioration of skin fibrosis in scleroderma. The underlying molecular basis of agonist-activated PPAR-γ-mediated suppression of profibrogenic signaling and skin fibrogenesis is also highlighted.

Targeting CD38-dependent NAD+ metabolism to mitigate multiple organ fibrosis

The processes underlying synchronous multiple organ fibrosis in systemic sclerosis (SSc) remain poorly understood. Age-related pathologies are associated with organismal decline in nicotinamide adenine dinucleotide (NAD⁺) that is due to dysregulation of NAD⁺ homeostasis and involves the NADase CD38. We now show that CD38 is upregulated in patients with diffuse cutaneous SSc, and CD38 levels in the skin associate with molecular fibrosis signatures, as well as clinical fibrosis scores, while expression of key NAD⁺-synthesizing enzymes is unaltered. Boosting NAD⁺ via genetic or pharmacological CD38 targeting or NAD⁺ precursor supplementation protected mice from skin, lung, and peritoneal fibrosis. In mechanistic experiments, CD38 was found to reduce NAD⁺ levels and sirtuin activity to augment cellular fibrotic responses, while inhibiting CD38 had the opposite effect. Thus, we identify CD38 upregulation and resulting disrupted NAD⁺ homeostasis as a fundamental mechanism driving fibrosis in SSc, suggesting that CD38 might represent a novel therapeutic target.

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CD38 shows elevated expression in skin biopsies of patients with systemic sclerosis

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Elevated CD38 is associated with reduced NAD⁺ and augmented fibrotic responses

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Genetic loss of CD38 is associated with increased NAD⁺ levels and attenuated fibrosis

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NAD⁺ boosting via CD38 inhibition or NR supplementation prevents multi-organ fibrosis

Epigenetics and systemic sclerosis: An answer to disease onset and evolution?

There is growing evidence that implicates epigenetic modification in the pathogenesis of systemic sclerosis (SSc). The complexity of epigenetic regulation and its dynamic nature complicate the investigation of its role in the disease. We will review the current literature for factors that link epigenetics to SSc by discussing DNA methylation, histone acetylation and methylation, and non-coding RNAs (ncRNAs), particularly microRNA changes in endothelial cells, fibroblasts (FBs), and lymphocytes. These three cell types are significantly involved in the early stages and throughout the course of the disease and are particularly vulnerable to epigenetic regulation. The pathogenesis of SSc is likely related to modifications of the epigenome by environmental signals in individuals with a specific genetic makeup. The epigenome is an attractive therapeutic target; however, successful epigenetics-based treatments require a better understanding of the molecular mechanisms controlling the epigenome and its alteration in the disease.

p300 in Cardiac Development and Accelerated Cardiac Aging

The heart is the first functional organ that develops during embryonic development. While a heartbeat indicates life, cessation of a heartbeat signals the end of life. Heart disease, due either to congenital defects or to acquired dysfunctions in adulthood, remains the leading cause of death worldwide. Epigenetics plays a key role in both embryonic heart development and heart disease in adults. Stress-induced vascular injury activates pathways involved in pathogenesis of accelerated cardiac aging that includes cellular dysfunction, pathological cardiac hypertrophy, diabetic cardiomyopathy, cardiac matrix remodeling, cardiac dysfunction and heart failure. Acetyltransferase p300 (p300), a major epigenetic regulator, plays a pivotal role in heart development during embryogenesis, as deficiency or abnormal expression of p300 leads to embryonic death at early gestation periods due to deformation of the heart and neural tube. Acetyltransferase p300 controls heart development through histone acetylation-mediated chromatin remodeling and transcriptional regulation of genes required for cardiac development. In adult hearts, p300 is differentially expressed in different chambers and epigenetically controls cardiac gene expression. Deregulation of p300, in response to prohypertrophic and profibrogenic stress signals, is associated with increased recruitment of p300 to several genes including transcription factors, increased acetylation of specific lysines in histones and transcription factors, altered chromatin organization, and increased hypertrophic and fibrogenic gene expression. Cardiac hypertrophy and myocardial fibrogenesis are common pathological manifestations of several stress-induced accelerated cardiac aging-related pathologies, including high blood pressure-induced or environmentally induced cardiac hypertrophy, myocardial infarction, diabetes-induced cardiomyopathy, and heart failure. Numerous studies using cellular and animal models clearly indicate that pharmacologic or genetic normalization of p300 activity has the potential to prevent or halt the progression of cardiac aging pathologies. Based on these preclinical studies, development of safe, non-toxic, small molecule inhibitors/epidrugs targeting p300 is an ideal approach to control accelerated cardiac aging-related deaths worldwide.

Epigenetic Modifiers as Potential Therapeutic Targets in Diabetic Kidney Disease

Diabetic kidney disease is one of the fastest growing causes of death worldwide. Epigenetic regulators control gene expression and are potential therapeutic targets. There is functional interventional evidence for a role of DNA methylation and the histone post-translational modifications-histone methylation, acetylation and crotonylation-in the pathogenesis of kidney disease, including diabetic kidney disease. Readers of epigenetic marks, such as bromodomain and extra terminal (BET) proteins, are also therapeutic targets. Thus, the BD2 selective BET inhibitor apabetalone was the first epigenetic regulator to undergo phase-3 clinical trials in diabetic kidney disease with an endpoint of kidney function. The direct therapeutic modulation of epigenetic features is possible through pharmacological modulators of the specific enzymes involved and through the therapeutic use of the required substrates. Of further interest is the characterization of potential indirect effects of nephroprotective drugs on epigenetic regulation. Thus, SGLT2 inhibitors increase the circulating and tissue levels of β-hydroxybutyrate, a molecule that generates a specific histone modification, β-hydroxybutyrylation, which has been associated with the beneficial health effects of fasting. To what extent this impact on epigenetic regulation may underlie or contribute to the so-far unclear molecular mechanisms of cardio- and nephroprotection offered by SGLT2 inhibitors merits further in-depth studies.

The contribution of epigenetics to the pathogenesis and gender dimorphism of systemic sclerosis: a comprehensive overview

Systemic sclerosis (SSc) is a life-threatening connective tissue disorder of unknown etiology characterized by widespread vascular injury and dysfunction, impaired angiogenesis, immune dysregulation and progressive fibrosis of the skin and internal organs. Over the past few years, a new trend of investigations is increasingly reporting aberrant epigenetic modifications in genes related to the pathogenesis of SSc, suggesting that, besides genetics, epigenetics may play a pivotal role in disease development and clinical manifestations. Like many other autoimmune diseases, SSc presents a striking female predominance, and even if the reason for this gender imbalance has yet to be completely understood, it appears that the X chromosome, which contains many gender and immune-related genes, could play a role in such gender-biased prevalence. Besides a short summary of the genetic background of SSc, in this review we provide a comprehensive overview of the most recent insights into the epigenetic modifications which underlie the pathophysiology of SSc. A particular focus is given to genetic variations in genes located on the X chromosome as well as to the main X-linked epigenetic modifications that can influence SSc susceptibility and clinical phenotype. On the basis of the most recent advances, there is realistic hope that integrating epigenetic data with genomic, transcriptomic, proteomic and metabolomic analyses may provide in the future a better picture of their functional implications in SSc, paving the right way for a better understanding of disease pathogenesis and the development of innovative therapeutic approaches.

Plumbagin Suppresses Pulmonary Fibrosis via Inhibition of p300 Histone Acetyltransferase Activity

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrosing interstitial lung disease with a poor prognosis similar to that of malignancy. The causes of IPF are not clearly known, and there is no effective therapy to date. In this study, the natural compound plumbagin, which was isolated from Plumbago rosea root extract, was screened for p300 inhibitory activity. Plumbagin specifically inhibited the activity of p300 toward histone acetyltransferases. Plumbagin treatment significantly suppressed transforming growth factor-β-induced profibrotic target-gene expression and proliferation of fibroblast cell lines. Moreover, plumbagin significantly inhibited bleomycin-induced pulmonary fibrosis in mice. Taken together, these data demonstrate the inhibitory effects of plumbagin on lung fibrosis and its promise as a therapeutic agent for IPF.

JQ1, a bromodomain inhibitor, suppresses Th17 effectors by blocking p300-mediated acetylation of RORγt

BACKGROUND AND PURPOSE

Th17 cells play critical roles in chronic inflammation, including fibrosis. Histone acetyltransferase p300, a bromodomain-containing protein, acetylates RORγt and promotes Th17 cell development. The bromodomain inhibitor JQ1 was shown to alleviate Th17-mediated pathologies, but the underlying mechanism remains unclear. We hypothesized that JQ1 suppresses the response of Th17 cells by impairing p300-mediated acetylation of RORγt.

EXPERIMENTAL APPROACH

The effect of JQ1 on p300-mediated acetylation of RORγt was investigated in HEK293T (overexpressing Flag-p300 and Myc-RORγt) and human Th17 cells through immunoprecipitation and western blotting. To determine the regions of p300 responsible for JQ1-mediated suppression of HAT activity, we performed HAT assays on recombinant p300 fragments with/without the bromodomain, after exposure to JQ1. Additionally, the effect of JQ1 on p300-mediated acetylation of RORγt and Th17 cell function was verified in vivo, using murine Schistosoma-induced fibrosis models. Liver injury was assessed by histopathological examination and measurement of serum enzyme levels. Expression of Th17 effectors was detected by qRT-PCR, whereas IL-17- and RORγt-positive granuloma cells were detected by FACS.

KEY RESULTS

JQ1 impaired p300-mediated RORγt acetylation in human Th17 and HEK293T cells. JQ1 failed to suppress the acetyltransferase activity of p300 fragments lacking the bromodomain. JQ1 treatment attenuated Schistosoma-induced fibrosis in mice, by inhibiting RORγt acetylation and IL-17 expression.

CONCLUSIONS AND IMPLICATIONS

JQ1 impairs p300-mediated RORγt acetylation, thus reducing the expression of RORγt target genes, including Th17-specific cytokines. JQ1-mediated inhibition of p300 acetylase activity requires the p300 bromodomain. Strategies targeting p300 may provide new therapeutic approaches for controlling Th17-related diseases.

Epigenetic Control of Scleroderma: Current Knowledge and Future Perspectives

PURPOSE OF REVIEW

Epigenetics has been implicated in the pathogenesis of systemic sclerosis (SSc). In this review, the involvement of the three epigenetic mechanisms in SSc development and progression-DNA methylation, histone modifications, and non-coding RNAs-will be discussed.

RECENT FINDINGS

Alteration in epigenetics was observed in immune cells, dermal fibroblasts, and endothelial cells derived from SSc patients. Genes that are affected include those involved in immune cell function and differentiation, TGFβ and Wnt pathways, extracellular matrix accumulation, transcription factors, and angiogenesis. All the studies remain in the pre-clinical stage. Extensive research provides evidence that epigenetic alterations are critical for SSc pathogenesis. Future epigenomic studies will undoubtedly continue to broaden our understanding of disease pathogenesis and clinical heterogeneity. They will also provide the scientific basis for repurposing epigenetic-modifying agents for SSc patients.

Epigenetics of scleroderma: Integrating genetic, ethnic, age, and environmental effects

Scleroderma or systemic sclerosis is thought to result from the interplay between environmental or non-genetic factors in a genetically susceptible individual. Epigenetic modifications are influenced by genetic variation and environmental exposures, and change with chronological age and between populations. Despite progress in identifying genetic, epigenetic, and environmental risk factors, the underlying mechanism of systemic sclerosis remains unclear. Since epigenetics provides the regulatory mechanism linking genetic and non-genetic factors to gene expression, understanding the role of epigenetic regulation in systemic sclerosis will elucidate how these factors interact to cause systemic sclerosis. Among the cell types under tight epigenetic control and susceptible to epigenetic dysregulation, immune cells are critically involved in early pathogenic events in the progression of fibrosis and systemic sclerosis. This review starts by summarizing the changes in DNA methylation, histone modification, and non-coding RNAs associated with systemic sclerosis. It then discusses the role of genetic, ethnic, age, and environmental effects on epigenetic regulation, with a focus on immune system dysregulation. Given the potential of epigenome editing technologies for cell reprogramming and as a therapeutic approach for durable gene regulation, this review concludes with a prospect on epigenetic editing. Although epigenomics in systemic sclerosis is in its infancy, future studies will help elucidate the regulatory mechanisms underpinning systemic sclerosis and inform the design of targeted epigenetic therapies to control its dysregulation.

New insights into the genetics and epigenetics of systemic sclerosis

Systemic sclerosis (SSc) is a severe autoimmune disease that is characterized by vascular abnormalities, immunological alterations and fibrosis of the skin and internal organs. The results of genetic studies in patients with SSc have revealed statistically significant genetic associations with disease manifestations and progression. Nevertheless, genetic susceptibility to SSc is moderate, and the functional consequences of genetic associations remain only partially characterized. A current hypothesis is that, in genetically susceptible individuals, epigenetic modifications constitute the driving force for disease initiation. As epigenetic alterations can occur years before fibrosis appears, these changes could represent a potential link between inflammation and tissue fibrosis. Epigenetics is a fast-growing discipline, and a considerable number of important epigenetic studies in SSc have been published in the past few years that span histone post-translational modifications, DNA methylation, microRNAs and long non-coding RNAs. This Review describes the latest insights into genetic and epigenetic contributions to the pathogenesis of SSc and aims to provide an improved understanding of the molecular pathways that link inflammation and fibrosis. This knowledge will be of paramount importance for the development of medicines that are effective in treating or even reversing tissue fibrosis.

Epigenetic Regulation of Endothelial-to-Mesenchymal Transition in Chronic Heart Disease

Endothelial-to-mesenchymal transition (EndMT) is a process in which endothelial cells lose their properties and transform into fibroblast-like cells. This transition process contributes to cardiac fibrosis, a common feature of patients with chronic heart failure. To date, no specific therapies to halt or reverse cardiac fibrosis are available, so knowledge of the underlying mechanisms of cardiac fibrosis is urgently needed. In addition, EndMT contributes to other cardiovascular pathologies such as atherosclerosis and pulmonary hypertension, but also to cancer and organ fibrosis. Remarkably, the molecular mechanisms driving EndMT are largely unknown. Epigenetics play an important role in regulating gene transcription and translation and have been implicated in the EndMT process. Therefore, epigenetics might be the missing link in unraveling the underlying mechanisms of EndMT. Here, we review the involvement of epigenetic regulators during EndMT in the context of cardiac fibrosis. The role of DNA methylation, histone modifications (acetylation and methylation), and noncoding RNAs (microRNAs, long noncoding RNAs, and circular RNAs) in the facilitation and inhibition of EndMT are discussed, and potential therapeutic epigenetic targets will be highlighted.

Evolving insights into the cellular and molecular pathogenesis of fibrosis in systemic sclerosis

Systemic sclerosis (SSc, scleroderma) is a complex multisystem disease characterized by autoimmunity, vasculopathy, and most notably, fibrosis. Multiple lines of evidence demonstrate a variety of emerging cellular and molecular pathways which are relevant to fibrosis in SSc. The myofibroblast remains the key effector cell in SSc. Understanding the development, differentiation, and function of the myofibroblast is therefore crucial to understanding the fibrotic phenotype of SSc. Studies now show that (1) multiple cell types give rise to myofibroblasts, (2) fibroblasts and myofibroblasts are heterogeneous, and (3) that a large number of (primarily immune) cells have important influences on the transition of fibroblasts to an activated myofibroblasts. In SSc, this differentiation process involves multiple pathways, including well known signaling cascades such as TGF-β and Wnt/β-Catenin signaling, as well as epigenetic reprogramming and a number of more recently defined cellular pathways. After reviewing the major and emerging cellular and molecular mechanisms underlying SSc, this article looks to identify clinical applications where this new molecular knowledge may allow for targeted treatment and personalized medicine approaches.

Nicotinamide riboside protects against liver fibrosis induced by CCl4 via regulating the acetylation of Smads signaling pathway

AIMS

Increasing nicotinamide adenine dinucleotide (NAD⁺) by Nicotinamide riboside (NR) provides protective benefits in multiple disorders. However, the role of NR on liver fibrosis is unclear. We performed in vivo and in vitro experiments to test the hepatic protective effects of NR against liver fibrosis and the underlying mechanisms.

MATERIALS AND METHODS

Mice were injected with CCl₄ to establish liver fibrosis model. NR was given by gavage to explore the hepatic protection of NR. LX-2 cells were given a TGF-β stimulation ± NR, the activation of LX-2 cells and the acetylation of Smads were analyzed. To further confirm the role of Sirt1 on the protective pathway of NR, we knockdown Sirt1 in LX-2 cells.

KEY FINDINGS

We found NR could prevent liver fibrosis and reverse the existing liver fibrosis. NR inhibited the activation of LX-2 cells induced by TGF-β, activated Sirt1 and deacetylated Smad2/3. Sirt1 knockdown diminished the inhibiting effect of NR on LX-2 cells activation, and increased expressions of acetylated Smads. In conclusion, NR could prevent liver fibrosis via suppressing activation of hepatic stellate cells (HSCs). This protective effect was mediated by regulating the acetylation of Smads signaling pathway.

SIGNIFICANCE

NR protected mice against liver fibrosis induced by CCl₄. NR suppressed activation of hepatic stellate cells induced by TGF-β. NR protects liver fibrosis via increasing the activity of Sirt1 and decreasing the expression of P300, resulting in the deacetylation of Smads in stellate cells.

The Role of Epigenetic Modifications in Systemic Sclerosis: A Druggable Target

Systemic sclerosis (SSc) is a rare autoimmune disorder characterised by skin fibrosis that often also affects internal organs, eventually resulting in mortality. Although management of the symptoms has extended lifespan, patients still suffer from poor quality of life, hence the need for improved therapies. Development of efficacious treatments has been stymied by the unknown aetiology, although recent advancements suggest a potentially key role for epigenetics - the regulation of gene expression by noncoding RNAs and chemical modifications to DNA or DNA-associated proteins. Herein, the evidence implicating epigenetics in the pathogenesis of SSc is discussed with an emphasis on the therapeutic potential this introduces to the field - particularly the repurposing of epigenetic targeting cancer therapeutics and newly emerging miRNA-based strategies.

Reactive Oxygen Species Drive Epigenetic Changes in Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) develops months to years after initial radiation exposure. RIF occurs when normal fibroblasts differentiate into myofibroblasts and lay down aberrant amounts of extracellular matrix proteins. One of the main drivers for developing RIF is reactive oxygen species (ROS) generated immediately after radiation exposure. Generation of ROS is known to induce epigenetic changes and cause differentiation of fibroblasts to myofibroblasts. Several antioxidant compounds have been shown to prevent radiation-induced epigenetic changes and the development of RIF. Therefore, reviewing the ROS-linked epigenetic changes in irradiated fibroblast cells is essential to understand the development and prevention of RIF.

Intriguing Relationships Between Cancer and Systemic Sclerosis: Role of the Immune System and Other Contributors

Systemic sclerosis (SSc) is an autoimmune connective tissue disorder, characterized by multisystem involvement, vasculopathy, and fibrosis. An increased risk of malignancy is observed in SSc (including breast and lung cancers), and in a subgroup of patients with specific autoantibodies (i.e., anti-RNA polymerase III and related autoantibodies), SSc could be a paraneoplastic syndrome and might be directly related to an immune response against cancer. Herein, we reviewed the literature, focusing on the most recent articles, and shed light onto the potential relationship between cancer and scleroderma regarding temporal and immunological dimensions.

Epigenetic Regulation of Myofibroblast Phenotypes in Fibrosis

Purpose of Review

Myofibroblasts are the fundamental drivers of fibrosing disorders; there is great value in better defining epigenetic networks involved in myofibroblast behavior. Complex epigenetic paradigms, which are likely organ and/or disease specific, direct pathologic myofibroblast phenotypes. In this review, we highlight epigenetic regulators and the mechanisms through which they shape myofibroblast phenotype in fibrotic diseases of different organs.

Recent Findings

Hundreds of genes and their expression contribute to the myofibroblast transcriptional regime influencing myofibroblast phenotype. An increasingly large number of epigenetic modifications have been identified in the regulation of these signaling pathways driving myofibroblast activation and disease progression. Drugs that inhibit or reverse profibrotic epigenetic modifications have shown promise in vitro and in vivo; however, no current epigenetic therapies have been approved to treat fibrosis. Newly described epigenetic mechanisms will be mentioned, along with potential therapeutic targets and innovative strategies to further understand myofibroblast-directed fibrosis.

Summary

Epigenetic regulators that direct myofibroblast behavior and differentiation into pathologic myofibroblast phenotypes in fibrotic disorders comprise both overlapping and organ-specific epigenetic mechanisms.

Epigenetics and pathogenesis of systemic sclerosis; the ins and outs

The pathogenesis of many diseases is influenced by environmental factors which can affect human genome and be inherited from generation to generation. Adverse environmental stimuli are recognized through the epigenetic regulatory complex, leading to gene expression alteration, which in turn culminates in disease outcomes. Three epigenetic regulatory mechanisms modulate the manifestation of a gene, namely DNA methylation, histone changes, and microRNAs. Both epigenetics and genetics have been implicated in the pathogenesis of systemic sclerosis (SSc) disease. Genetic inheritance rate of SSc is low and the concordance rate in both monozygotic (MZ) and dizygotic (DZ) twins is little, implying other possible pathways in SSc pathogenesis scenario. Here, we provide an extensive overview of the studies regarding different epigenetic events which may offer insights into the pathology of SSc. Furthermore, epigenetic-based interventions to treat SSc patients were discussed.

A novel acetyltransferase p300 inhibitor ameliorates hypertension-associated cardio-renal fibrosis

Hypertension-associated end-organ damage commonly leads to cardiac and renal fibrosis. As no effective anti-fibrotic therapy currently exists, the unchecked progression of fibrogenesis manifests as cardio-renal failure and early death. We have previously shown that FATp300-p300 with intrinsic factor acetyltransferase activity-is an essential epigenetic regulator of fibrogenesis, and is elevated in several fibrotic tissues. In this report, we investigate the therapeutic efficacy of a novel FATp300 inhibitor, L002, in a murine model of hypertensive cardio-renal fibrosis. Additionally, we examine the effects of L002 on cellular pro-fibrogenic processes and provide mechanistic insights into its antifibrogenic action. Utilizing cardiac fibroblasts, podocytes, and mesangial cells, we demonstrate that L002 blunts FATp300-mediated acetylation of specific histones. Further, incubating cells with L002 suppresses several pro-fibrogenic processes including cellular proliferation, migration, myofibroblast differentiation and collagen synthesis. Importantly, systemic administration of L002 in mice reduces hypertension-associated pathological hypertrophy, cardiac fibrosis and renal fibrosis. The anti-hypertrophic and anti-fibrotic effects of L002 were independent of blood pressure regulation. Our work solidifies the role of epigenetic regulator FATp300 in fibrogenesis and establishes it as a pharmacological target for reducing pathological matrix remodeling and associated pathologies. Additionally, we discover a new therapeutic role of L002, as it ameliorates hypertension-induced cardio-renal fibrosis and antagonizes pro-fibrogenic responses in fibroblasts, podocytes and mesangial cells.

Protective effect of α-lipoic acid against radiation-induced fibrosis in mice

Radiation-induced fibrosis (RIF) is one of the most common late complications of radiation therapy. We found that α-lipoic acid (α-LA) effectively prevents RIF. In RIF a mouse model, leg contracture assay was used to test the in vivo efficacy of α-LA. α-LA suppressed the expression of pro-fibrotic genes after irradiation, both in vivo and in vitro, and inhibited the up-regulation of TGF-β1-mediated p300/CBP activity. Thus, α-LA prevents radiation-induced fibrosis (RIF) by inhibiting the transcriptional activity of NF-κB through inhibition of histone acetyltransferase activity. α-LA is a new therapeutic methods that can be used in the prevention-treatment of RIF.