ZNF469 is a profibrotic regulator of extracellular matrix in hepatic stellate cells

Activation of quiescent hepatic stellate cells (HSCs) into proliferative myofibroblasts drives extracellular cellular matrix (ECM) accumulation and liver fibrosis; nevertheless, the transcriptional network that promotes such a process is not completely understood. ZNF469 is a putative C2H2 zinc finger protein that may bind to specific genome sequences. It is found to be upregulated upon HSC activation; however, the molecular function of ZNF469 is completely unknown. Here, we show that knockdown of ZNF469 in primary human HSCs impaired proliferation, migration, and collagen production. Conversely, overexpression of ZNF469 in HSCs yielded the opposite results. Transforming growth factor-β 1 promoted expression of ZNF469 in a Smad3-dependent manner, where the binding of Smad3 was confirmed at the ZNF469 promoter. RNA sequencing data of ZNF469-knockdown HSCs revealed the ECM-receptor interaction, which provides structural and signaling support to cells, was the most affected pathway, and significant downregulation of various collagen and proteoglycan genes was observed. To investigate the function of ZNF469, we cloned a full-length open reading frame of ZNF469 with an epitope tag and identified a nuclear localization of the protein. Luciferase reporter and chromatin immunoprecipitation assays revealed the presence of ZNF469 at the promoter of ECM genes, supporting its function as a transcription factor. Analysis of human fibrotic and cirrhotic tissues showed increased expression of ZNF469 and a positive correlation between expression levels of ZNF469 and ECM genes. Moreover, this observation was similar in other fibrotic organs, including the heart, lung, and skin, suggesting that myofibroblasts from various origins generally require ZNF469 to promote ECM production. Together, this study is the first to reveal the role of ZNF469 as a profibrotic factor in HSCs and suggests ZNF469 as a novel target for antifibrotic therapy.

The role and mechanism of TXNDC5 in disease progression

Thioredoxin domain containing protein-5 (TXNDC5), also known as endothelial protein-disulfide isomerase (Endo-PDI), is confined to the endoplasmic reticulum through the structural endoplasmic reticulum retention signal (KDEL), is a member of the PDI protein family and is highly expressed in the hypoxic state. TXNDC5 can regulate the rate of disulfide bond formation, isomerization and degradation of target proteins through its function as a protein disulfide isomerase (PDI), thereby altering protein conformation, activity and improving protein stability. Several studies have shown that there is a significant correlation between TXNDC5 gene polymorphisms and genetic susceptibility to inflammatory diseases such as rheumatoid, fibrosis and tumors. In this paper, we detail the expression characteristics of TXNDC5 in a variety of diseases, summarize the mechanisms by which TXNDC5 promotes malignant disease progression, and summarize potential therapeutic strategies to target TXNDC5 for disease treatment.

Ferroptosis in organ fibrosis: From mechanisms to therapeutic medicines

Fibrosis occurs in many organs, and its sustained progress can lead to organ destruction and malfunction. Although numerous studies on organ fibrosis have been carried out, its underlying mechanism is largely unknown, and no ideal treatment is currently available. Ferroptosis is an iron-dependent process of programmed cell death that is characterized by lipid peroxidation. In the past decade, a growing body of evidence demonstrated the association between ferroptosis and fibrotic diseases, while targeting ferroptosis may serve as a potential therapeutic strategy. This review highlights recent advances in the crosstalk between ferroptosis and organ fibrosis, and discusses ferroptosis-targeted therapeutic approaches against fibrosis that are currently being explored.

Antioxidant therapy against TGF-β/SMAD pathway involved in organ fibrosis

Fibrosis refers to excessive build-up of scar tissue and extracellular matrix components in different organs. In recent years, it has been revealed that different cytokines and chemokines, especially Transforming growth factor beta (TGF-β) is involved in the pathogenesis of fibrosis. It has been shown that TGF-β is upregulated in fibrotic tissues, and contributes to fibrosis by mediating pathways that are related to matrix preservation and fibroblasts differentiation. There is no doubt that antioxidants protect against different inflammatory conditions by reversing the effects of nitrogen, oxygen and sulfur-based reactive elements. Oxidative stress has a direct impact on chronic inflammation, and as results, prolonged inflammation ultimately results in fibrosis. Different types of antioxidants, in the forms of vitamins, natural compounds or synthetic ones, have been proven to be beneficial in the protection against fibrotic conditions both in vitro and in vivo. In this study, we reviewed the role of different compounds with antioxidant activity in induction or inhibition of TGF-β/SMAD signalling pathway, with regard to different fibrotic conditions such as gastro-intestinal fibrosis, cardiac fibrosis, pulmonary fibrosis, skin fibrosis, renal fibrosis and also some rare cases of fibrosis, both in animal models and cell lines.

Targeting cluster of differentiation 26 / dipeptidyl peptidase 4 (CD26/DPP4) in organ fibrosis

Cluster of differentiation 26 (CD26)/dipeptidyl peptidase 4 (DPP4) is an exopeptidase that is expressed as a transmembrane protein in many organs but also present in a circulating soluble form. Beyond its enzymatic and costimulatory activity, CD26/DPP4 is involved in the pathogenesis of chronic fibrotic diseases across many organ types, such as liver cirrhosis, kidney fibrosis and lung fibrosis. Organ fibrosis is associated with a high morbidity and mortality, and there are no causative therapies that can effectively attenuate the progress of the disease. Growing evidence suggests that inhibiting CD26/DPP4 can modulate the profibrotic tissue microenvironment and thus reduce fibrotic changes within affected organs. This review summarizes the role of CD26/DPP4 in fibroproliferative disorders and highlights new opportunities for an antifibrotic treatment by CD26/DPP4 inhibition. As a major advantage, CD26/DPP4 inhibitors have been in safe and routine clinical use in type 2 diabetes for many years and thus qualify for repurposing to repurpose as a promising therapeutic against fibrosis. LINKED ARTICLES: This article is part of a themed issue on Translational Advances in Fibrosis as a Therapeutic Target. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.22/issuetoc.

TGF-β as A Master Regulator of Aging-Associated Tissue Fibrosis

Fibrosis is the abnormal accumulation of extracellular matrix proteins such as collagen and fibronectin. Aging, injury, infections, and inflammation can cause different types of tissue fibrosis. Numerous clinical investigations have shown a correlation between the degree of liver and pulmonary fibrosis in patients and telomere length and mitochondrial DNA content, both of which are signs of aging. Aging involves the gradual loss of tissue function over time, which results in the loss of homeostasis and, ultimately, an organism's fitness. A major feature of aging is the accumulation of senescent cells. Senescent cells abnormally and continuously accumulate in the late stages of life, contributing to age-related fibrosis and tissue deterioration, among other aging characteristics. Furthermore, aging generates chronic inflammation, which results in fibrosis and decreases organ function. This finding suggests that fibrosis and aging are closely related. The transforming growth factor-beta (TGF-β) superfamily plays a crucial role in the physiological and pathological processes of aging, immune regulation, atherosclerosis, and tissue fibrosis. In this review, the functions of TGF-β in normal organs, aging, and fibrotic tissues is discussed: TGF-β signalling is altered with age and is an indicator of pathology associated with tissue fibrosis. In addition, this review discusses the potential targeting of noncoding.

Late-Onset Esophageal Perforation After Salvage Anterior Cervical Spine Surgery in a Patient With Systemic Sclerosis

Systemic sclerosis (SSc) is a systemic, immune-mediated disease characterized by abnormal cutaneous and organ-based fibrosis that results in progressive organ dysfunction including the esophagus. We herein report our experience of a patient with SSc who underwent salvage anterior cervical spine surgery that led to late-onset esophageal perforation. A 57-year-old female had progressive cervical kyphosis after laminoplasty for cervical spondylotic myelopathy. We performed anterior cervical discectomy and fusion using a stand-alone cage. Despite prolonged use of a neck collar, migration of the anterior cage was noted three months after surgery. Rapid progression of kyphotic deformity prompted us to perform revision surgery of circumferential cervical correction. However, conventional posterior surgery was precluded due to the extremely poor condition of her neck, including severely sclerotic skin and atrophic muscles. To address this, she underwent a posterior fusion with the closed technique and C4-C5 corpectomy and bone grafting using a low-profile anterior plate. One year after the surgery, CT and routine upper gastrointestinal endoscopy (UGE) showed no evidence of esophagus injury. She remained asymptomatic thereafter. Over three years after her last surgery, however, follow-up CT incidentally revealed an abnormal air leak around the anterior plate. UGE demonstrated large esophagus perforation with the exposed metal plate. As she had already been on parenteral nutrition due to the disease progression of SSc, we decided not to remove the implant. Potential esophagus perforation after anterior cervical spine surgery, even years later, should be considered regardless of the patient's symptoms, such as chest pain and dysphagia. Spine surgeons need to be cognizant of the fragility of the esophagus, especially in patients with SSc. For patients with SSc, posterior reconstruction alone is recommended as a relatively safe option, even with a suboptimal skin condition.

The effect of the cyclic GMP-AMP synthase-stimulator of interferon genes signaling pathway on organ inflammatory injury and fibrosis

The cyclic GMP-AMP synthase-stimulator of interferon genes signal transduction pathway is critical in innate immunity, infection, and inflammation. In response to pathogenic microbial infections and other conditions, cyclic GMP-AMP synthase (cGAS) recognizes abnormal DNA and initiates a downstream type I interferon response. This paper reviews the pathogenic mechanisms of stimulator of interferon genes (STING) in different organs, including changes in fibrosis-related biomarkers, intending to systematically investigate the effect of the cyclic GMP-AMP synthase-stimulator of interferon genes signal transduction in inflammation and fibrosis processes. The effects of stimulator of interferon genes in related auto-inflammatory and neurodegenerative diseases are described in this article, in addition to the application of stimulator of interferon genes-related drugs in treating fibrosis.

Vaccination-based immunotherapy to target profibrotic cells in liver and lung

Fibrosis is the final path of nearly every form of chronic disease, regardless of the pathogenesis. Upon chronic injury, activated, fibrogenic fibroblasts deposit excess extracellular matrix, and severe tissue fibrosis can occur in virtually any organ. However, antifibrotic therapies that target fibrogenic cells, while sparing homeostatic fibroblasts in healthy tissues, are limited. We tested whether specific immunization against endogenous proteins, strongly expressed in fibrogenic cells but highly restricted in quiescent fibroblasts, can elicit an antigen-specific cytotoxic T cell response to ameliorate organ fibrosis. In silico epitope prediction revealed that activation of the genes Adam12 and Gli1 in profibrotic cells and the resulting "self-peptides" can be exploited for T cell vaccines to ablate fibrogenic cells. We demonstrate the efficacy of a vaccination approach to mount CD8⁺ T cell responses that reduce fibroblasts and fibrosis in the liver and lungs in mice. These results provide proof of principle for vaccination-based immunotherapies to treat fibrosis.

Progressive liver, kidney, and heart degeneration in children and adults affected by TULP3 mutations

Organ fibrosis is a shared endpoint of many diseases, yet underlying mechanisms are not well understood. Several pathways governed by the primary cilium, a sensory antenna present on most vertebrate cells, have been linked with fibrosis. Ciliopathies usually start early in life and represent a considerable disease burden. We performed massively parallel sequencing by using cohorts of genetically unsolved individuals with unexplained liver and kidney failure and correlated this with clinical, imaging, and histopathological analyses. Mechanistic studies were conducted with a vertebrate model and primary cells. We detected bi-allelic deleterious variants in TULP3, encoding a critical adaptor protein for ciliary trafficking, in a total of 15 mostly adult individuals, originating from eight unrelated families, with progressive degenerative liver fibrosis, fibrocystic kidney disease, and hypertrophic cardiomyopathy with atypical fibrotic patterns on histopathology. We recapitulated the human phenotype in adult zebrafish and confirmed disruption of critical ciliary cargo composition in several primary cell lines derived from affected individuals. Further, we show interaction between TULP3 and the nuclear deacetylase SIRT1, with roles in DNA damage repair and fibrosis, and report increased DNA damage ex vivo. Transcriptomic studies demonstrated upregulation of profibrotic pathways with gene clusters for hypertrophic cardiomyopathy and WNT and TGF-β signaling. These findings identify variants in TULP3 as a monogenic cause for progressive degenerative disease of major organs in which affected individuals benefit from early detection and improved clinical management. Elucidation of mechanisms crucial for DNA damage repair and tissue maintenance will guide novel therapeutic avenues for this and similar genetic and non-genomic diseases.

A Microbiome-Derived Peptide Induces Apoptosis of Cells from Different Tissues

Apoptosis is a programmed cell death involved in embryogenesis and tissue homeostasis under physiological conditions. However, abnormalities in the process of apoptosis are implicated in the pathogenesis of various diseases. The human microbiota may release products that induce apoptosis of host cells. We recently identified a novel microbiome-derived peptide called corisin that worsens lung fibrosis by inducing apoptosis of lung epithelial cells. We hypothesized that corisin and a corisin-like peptide might also induce apoptosis of cells from different tissues. We cultured podocytes, renal tubular epithelial cells, keratinocytes, retinal and intestinal cells treated with corisin and evaluated apoptosis by flow cytometry and Western blotting. Although at different grades, flow cytometry analysis and Western blotting showed that corisin and a corisin-like peptide induced apoptosis of podocytes, keratinocytes, tubular epithelial cells, retinal, and intestinal cells. In addition, we found that corisin synergistically enhances the proapoptotic activity of transforming growth factor-β1 on podocytes. In conclusion, these results suggest that corisin and corisin-like peptides may play a role in the pathogenesis of disease in different organs by promoting apoptosis of parenchymal cells.

A Novel Splice Variant of Human TGF-β Type II Receptor Encodes a Soluble Protein and Its Fc-Tagged Version Prevents Liver Fibrosis in vivo

We describe, for the first time, a new splice variant of the human TGF-β type II receptor (TβRII). The new transcript lacks 149 nucleotides, resulting in a frameshift and the emergence of an early stop codon, rendering a truncated mature protein of 57 amino acids. The predicted protein, lacking the transmembrane domain and with a distinctive 13-amino-acid stretch at its C-terminus, was named TβRII-Soluble Endogenous (TβRII-SE). Binding predictions indicate that the novel 13-amino-acid stretch interacts with all three TGF-β cognate ligands and generates a more extensive protein–protein interface than TβRII. TβRII-SE and human IgG1 Fc domain were fused in frame in a lentiviral vector (Lv) for further characterization. With this vector, we transduced 293T cells and purified TβRII-SE/Fc by A/G protein chromatography from conditioned medium. Immunoblotting revealed homogeneous bands of approximately 37 kDa (reduced) and 75 kDa (non-reduced), indicating that TβRII-SE/Fc is secreted as a disulfide-linked homodimer. Moreover, high-affinity binding of TβRII-SE to the three TGF-β isoforms was confirmed by surface plasmon resonance (SPR) analysis. Also, intrahepatic delivery of Lv.TβRII-SE/Fc in a carbon tetrachloride-induced liver fibrosis model revealed amelioration of liver injury and fibrosis. Our results indicate that TβRII-SE is a novel member of the TGF-β signaling pathway with distinctive characteristics. This novel protein offers an alternative for the prevention and treatment of pathologies caused by the overproduction of TGF-β ligands.

Enzymatic cross-linking of collagens in organ fibrosis - resolution and assessment

Introduction: Enzymatic cross-linking of the collagens within the extracellular matrix (ECM) catalyzed by enzymes such as lysyl oxidase (LOX) and lysyl oxidase like-enzymes 1-4 (LOXL), transglutaminase 2 (TG2), and peroxidasin (PXDN) contribute to fibrosis progression through extensive collagen cross-linking. Studies in recent years have begun elucidating the important role of collagen cross-linking in perpetuating progression of organ fibrosis independently of inflammation through an increasingly stiff and noncompliant ECM. Therefore, collagen cross-linking and the cross-linking enzymes have become new targets in anti-fibrotic therapy as well as targets of novel biomarkers to properly assess resolution of the fibrotic ECM.Areas covered: The enzymatic actions of enzymes catalyzing collagen cross-linking and their relevance in organ fibrosis. Potential biomarkers specifically quantifying proteolytic fragments of collagen cross-linking is discussed based on Pubmed search done in November 2020 as well as the authors knowledge.Expert opinion: Current methods for the assessment of fibrosis involve the use of invasive and/or cumbersome and expensive methods such as tissue biopsies. Thus, an unmet need exists for the development and validation of minimally invasive biomarkers of proteolytic fragments of cross-linked collagens. These biomarkers may aid in the development and proper assessment of fibrosis resolution in coming years.

ER-anchored CRTH2 antagonizes collagen biosynthesis and organ fibrosis via binding LARP6

Excessive deposition of extracellular matrix, mainly collagen protein, is the hallmark of organ fibrosis. The molecular mechanisms regulating fibrotic protein biosynthesis are unclear. Here, we find that chemoattractant receptor homologous molecule expressed on TH2 cells (CRTH2), a plasma membrane receptor for prostaglandin D2, is trafficked to the endoplasmic reticulum (ER) membrane in fibroblasts in a caveolin-1-dependent manner. ER-anchored CRTH2 binds the collagen mRNA recognition motif of La ribonucleoprotein domain family member 6 (LARP6) and promotes the degradation of collagen mRNA in these cells. In line, CRTH2 deficiency increases collagen biosynthesis in fibroblasts and exacerbates injury-induced organ fibrosis in mice, which can be rescued by LARP6 depletion. Administration of CRTH2 N-terminal peptide reduces collagen production by binding to LARP6. Similar to CRTH2, bumetanide binds the LARP6 mRNA recognition motif, suppresses collagen biosynthesis, and alleviates bleomycin-triggered pulmonary fibrosis in vivo. These findings reveal a novel anti-fibrotic function of CRTH2 in the ER membrane via the interaction with LARP6, which may represent a therapeutic target for fibrotic diseases.

Modeling Progressive Fibrosis with Pluripotent Stem Cells Identifies an Anti-fibrotic Small Molecule

Progressive organ fibrosis accounts for one-third of all deaths worldwide, yet preclinical models that mimic the complex, progressive nature of the disease are lacking, and hence, there are no curative therapies. Progressive fibrosis across organs shares common cellular and molecular pathways involving chronic injury, inflammation, and aberrant repair resulting in deposition of extracellular matrix, organ remodeling, and ultimately organ failure. We describe the generation and characterization of an in vitro progressive fibrosis model that uses cell types derived from induced pluripotent stem cells. Our model produces endogenous activated transforming growth factor β (TGF-β) and contains activated fibroblastic aggregates that progressively increase in size and stiffness with activation of known fibrotic molecular and cellular changes. We used this model as a phenotypic drug discovery platform for modulators of fibrosis. We validated this platform by identifying a compound that promotes resolution of fibrosis in in vivo and ex vivo models of ocular and lung fibrosis.

Vijayaraj et al. describe the generation and characterization of an in vitro progressive fibrosis model that is broadly applicable to progressive organ fibrosis. They use it to identify a promising anti-fibrotic therapy that acts by activating normal tissue repair.

Targeting FSTL1 for Multiple Fibrotic and Systemic Autoimmune Diseases

Follistatin-like 1 (FSTL1) is a matricellular protein that is upregulated during development and disease, including idiopathic pulmonary fibrosis (IPF), keloid, and arthritis. The profibrotic and pro-inflammatory roles of FSTL1 have been intensively studied during the last several years, as well as in this report. We screened and identified epitope-specific monoclonal neutralizing antibodies (nAbs) to functionally block FSTL1. FSTL1 nAbs attenuated bleomycin-induced pulmonary and dermal fibrosis in vivo and transforming growth factor (TGF)-β1-induced dermal fibrosis ex vivo in human skin. In addition, FSTL1 nAbs significantly reduced existing lung fibrosis and skin fibrosis in experimental models. FSTL1 nAbs exerted their potent antifibrotic effects via reduced TGF-β1 responsiveness and subsequent myofibroblast activation and extracellular matrix production. We also observed that FSTL1 nAbs attenuated the severity of collagen-induced arthritis in mice, which was accompanied by reduced inflammatory responses in vitro. Our findings suggest that FSTL1 nAbs are a promising new therapeutic strategy for the treatment of multiple organ fibrosis and systemic autoimmune diseases.

IL-33/ST2 Axis in Organ Fibrosis

Interleukin 33 (IL-33) is highly expressed in barrier sites, acting via the suppression of tumorigenicity 2 receptor (ST2). IL-33/ST2 axis has long been known to play a pivotal role in immunity and cell homeostasis by promoting wound healing and tissue repair. However, it is also involved in the loss of balance between extensive inflammation and tissue regeneration lead to remodeling, the hallmark of fibrosis. The aim of the current review is to critically evaluate the available evidence regarding the role of the IL-33/ST2 axis in organ fibrosis. The role of the axis in tissue remodeling is better understood considering its crucial role reported in organ development and regeneration. Generally, the IL-33/ST2 signaling pathway has mainly anti-inflammatory/anti-proliferative effects; however, chronic tissue injury is responsible for pro-fibrogenetic responses. Regarding pulmonary fibrosis mature IL-33 enhances pro-fibrogenic type 2 cytokine production in an ST2- and macrophage-dependent manner, while full-length IL-33 is also implicated in the pulmonary fibrotic process in an ST2-independent, Th2-independent fashion. In liver fibrosis, evidence indicate that when acute and massive liver damage occurs, the release of IL-33 might act as an activator of tissue-protective mechanisms, while in cases of chronic injury IL-33 plays the role of a hepatic fibrotic factor. IL-33 signaling has also been involved in the pathogenesis of acute and chronic pancreatitis. Moreover, IL-33 could be used as an early marker for ulcer-associated activated fibroblasts and myofibroblast trans-differentiation; thus one cannot rule out its potential role in inflammatory bowel disease-associated fibrosis. Similarly, the upregulation of the IL-33/ST2 axismay contribute to tubular cell injury and fibrosis via epithelial to mesenchymal transition (EMT) of various cell types in the kidneys. Of note, IL-33 exerts a cardioprotective role via ST2 signaling, while soluble ST2 has been demonstrated as a marker of myocardial fibrosis. Finally, IL-33 is a crucial cytokine in skin pathology responsible for abnormal fibroblast proliferation, leukocyte infiltration and morphologic differentiation of human endothelial cells. Overall, emerging data support a novel contribution of the IL-33/ST2 pathway in tissue fibrosis and highlight the significant role of the Th2 pattern of immune response in the pathophysiology of organ fibrosis.

Mesenchymal Stem Cells in Fibrotic Disease

Fibrosis is associated with organ failure and high mortality and is commonly characterized by aberrant myofibroblast accumulation. Investigating the cellular origin of myofibroblasts in various diseases is thus a promising strategy for developing targeted anti-fibrotic treatments. Recent studies using genetic lineage tracing technology have implicated diverse organ-resident perivascular mesenchymal stem cell (MSC)-like cells and bone marrow-MSCs in myofibroblast generation during fibrosis development. In this Review, we give an overview of the emerging role of MSCs and MSC-like cells in myofibroblast-mediated fibrotic disease in the kidney, lung, heart, liver, skin, and bone marrow.

The Role of Transforming Growth Factor Beta-1 in the Progression of HIV/AIDS and Development of Non-AIDS-Defining Fibrotic Disorders

Even after attainment of sustained viral suppression following implementation of highly active antiretroviral therapy, HIV-infected persons continue to experience persistent, low-grade, systemic inflammation. Among other mechanisms, this appears to result from ongoing microbial translocation from a damaged gastrointestinal tract. This HIV-related chronic inflammatory response is paralleled by counteracting, but only partially effective, biological anti-inflammatory processes. Paradoxically, however, this anti-inflammatory response not only exacerbates immunosuppression but also predisposes for development of non-AIDS-related, non-communicable disorders. With respect to the pathogenesis of both sustained immunosuppression and the increased frequency of non-AIDS-related disorders, the anti-inflammatory/profibrotic cytokine, transforming growth factor-β1 (TGF-β1), which remains persistently elevated in both untreated and virally suppressed HIV-infected persons, may provide a common link. In this context, the current review is focused on two different, albeit related, harmful activities of TGF-β1 in HIV infection. First, on the spectrum of anti-inflammatory/immunosuppressive activities of TGF-β1 and the involvement of this cytokine, derived predominantly from T regulatory cells, in driving disease progression in HIV-infected persons via both non-fibrotic and profibrotic mechanisms. Second, the possible involvement of sustained elevations in circulating and tissue TGF-β1 in the pathogenesis of non-AIDS-defining cardiovascular, hepatic, pulmonary and renal disorders, together with a brief comment on potential TGF-β1-targeted therapeutic strategies.

[Research advances on baicalin and baicalein as potential therapeutic agents for fibrotic disease]

Tissue and organ fibrosis is the major cause for disability and death related to a variety of diseases worldwide. As specific therapies to halt, or even to reverse the existing tissue fibrosis are not yet available, it is of great significance to find new anti-fibrosis therapeutic agents. Tissue and organ fibrosis is a nonphysiological scarring process, associated with excessive deposition of extracellular matrix, and leads to impairment of organ function. Fibrotic lesions of all organs show similar histological abnormalities. In recent years, plenty of studies showed that Baicalin and baicalein had anti-fibrosis effects in different tissues or organs. In this paper, the effects and mechanisms of baicalin and baicalein on different organ fibrosis were reviewed. Baicalin and its aglycone baicalein had similarity in structural and pharmacological characteristics, with broad biotransformation effect within the body. The research suggested that baicalin and baicalein can suppress different tissue and organ fibrosis occurrence and development via various mechanisms, including down-regulating expression of promote-fibrosis cytokines, inhibiting pro-fibrogenic signaling pathways, anti-inflammatory and anti-oxidant effects. Though baicalin and baicalein are promising anti-fibrosis agents, there is still a long way to go before being approved as specific anti-fibrotic drugs.

BRD4 inhibition for the treatment of pathological organ fibrosis

Fibrosis is defined as excess deposition of extracellular matrix, resulting in tissue scarring and organ dysfunction. It is estimated that 45% of deaths in the developed world are due to fibrosis-induced organ failure. Despite the well-accepted role of fibrosis in the pathogenesis of numerous diseases, there are only two US Food and Drug Administration–approved anti-fibrotic therapies, both of which are currently restricted to the treatment of pulmonary fibrosis. Thus, organ fibrosis represents a massive unmet medical need. Here, we review recent findings suggesting that an epigenetic regulatory protein, BRD4, is a nodal effector of organ fibrosis, and we highlight the potential of small-molecule BRD4 inhibitors for the treatment of diverse fibrotic diseases.