Organ Fibrosis and Autoimmunity: The Role of Inflammation in TGFβ-Dependent EMT

Immune and Non-Immune Inflammatory Cells Involved in Autoimmune Fibrosis: New Discoveries

Fibrosis is an important health problem and its pathogenetic activation is still largely unknown. It can develop either spontaneously or, more frequently, as a consequence of various underlying diseases, such as chronic inflammatory autoimmune diseases. Fibrotic tissue is always characterized by mononuclear immune cells infiltration. The cytokine profile of these cells shows clear proinflammatory and profibrotic characteristics. Furthermore, the production of inflammatory mediators by non-immune cells, in response to several stimuli, can be involved in the fibrotic process. It is now established that defects in the abilities of non-immune cells to mediate immune regulation may be involved in the pathogenicity of a series of inflammatory diseases. The convergence of several, not yet well identified, factors results in the aberrant activation of non-immune cells, such as epithelial cells, endothelial cells, and fibroblasts, that, by producing pro-inflammatory molecules, exacerbate the inflammatory condition leading to the excessive and chaotic secretion of extracellular matrix proteins. However, the precise cellular mechanisms involved in this process have not yet been fully elucidated. In this review, we explore the latest discoveries on the mechanisms that initiate and perpetuate the vicious circle of abnormal communications between immune and non-immune cells, responsible for fibrotic evolution of inflammatory autoimmune diseases.

Alterations in histology of the aging salivary gland and correlation with the glandular inflammatory microenvironment

Aging-related salivary dysfunction typically causes reduced saliva volumes, which leads to debilitating consequences, even affecting patient quality of life. Understanding the respective clinicopathological characteristics and molecular mechanisms underlying salivary gland functioning during aging is vital for therapeutic purposes. Here, we provide a detailed atlas of the salivary gland microenvironment during aging, and we identified several phenotypes characteristic of aging salivary glands, including acini atrophy, increased inflammatory cells, altered immune responses, and accumulation of lysosomes and autophagosomes in aging cells, which may reflect progressive degeneration of salivary gland function. Furthermore, our analyses suggested significant enrichment of metabolic pathways in aging glands. Our results revealed complex cellular cross-talk among aging acinar cells, inflammatory factors, and immune responses. A natural aging animal model was established to verify these findings. This study provides mechanistic insights into age-related clinicopathogenesis, important implications for early diagnosis, and identification of new targets for improving salivary gland dysfunction.

Expression of transforming growth factor-β in oral submucous fibrosis: A systematic review

Oral submucous fibrosis (OSF) is a potentially malignant disorder characterised by inflammation and progressive fibrosis. Transforming growth factor-β (TGF-β) has been established as a master regulator of fibrosis in various organs; however, lack of systematic review on expression of TGF-β and its isoforms in OSF restrict the understanding of their behaviour in its pathogenesis. Online electronic databases, such as PubMed Medline, Cochrane Library, Embase, and Scopus, were searched from their respective dates of inception till 31st March 2022. Human studies related to TGF-β expression in histopathologically diagnosed OSF cases, with or without malignant transformation, were included and assessed using a Cochrane risk of bias assessment tool: For non randomised studies of interventions (ACROBAT NRSI). The electronic literature search yielded 394 articles. Of those, ten articles met the inclusion criteria and involved total of 579 OSF patients. The risk of bias (RoB) was low to moderate. These studies demonstrated a significant positive expression of TGF-β and its isoforms in OSF compared to that in normal tissue samples. An increased pan TGF-β expression was observed in the early stages of OSF, and an increased expression of TGF-β1 and TGF-β2 were seen in advanced stages of OSF. Stage wise expression of TGF-β3 has not been discussed in the included studies. No significant relationship was observed between epithelial dysplasia and TGF-β expression in OSF. The distinct pattern in the expression of pan TGF-β, TGF-β1 and TGF-β2 in various stages of OSF indicates their different roles in OSF progression. We believe isoform targeted studies exploring stage wise expression of the marker will open new treatment avenues for OSF.

Raman microspectroscopy identifies fibrotic tissues in collagen-related disorders via deconvoluted collagen type I spectra

Fibrosis is a consequence of the pathological remodeling of extracellular matrix (ECM) structures in the connective tissue of an organ. It is often caused by chronic inflammation, which over time, progressively leads to an excess deposition of collagen type I (COL I) that replaces healthy tissue structures, in many cases leaving a stiff scar. Increasing fibrosis can lead to organ failure and death; therefore, developing methods that potentially allow real-time monitoring of early onset or progression of fibrosis are highly valuable. In this study, the ECM structures of diseased and healthy human tissue from multiple organs were investigated for the presence of fibrosis using routine histology and marker-independent Raman microspectroscopy and Raman imaging. Spectral deconvolution of COL I Raman spectra allowed the discrimination of fibrotic and non-fibrotic COL I fibers. Statistically significant differences were identified in the amide I region of the spectral subpeak at 1608 cm^-1, which was deemed to be representative for structural changes in COL I fibers in all examined fibrotic tissues. Raman spectroscopy-based methods in combination with this newly discovered spectroscopic biomarker potentially offer a diagnostic approach to non-invasively track and monitor the progression of fibrosis. STATEMENT OF SIGNIFICANCE: Current diagnosis of fibrosis still relies on histopathological examination with invasive biopsy procedures. Although, several non-invasive imaging techniques such as positron emission tomography, single-photon emission computed tomography and second harmonic generation are gradually employed in preclinical or clinical studies, these techniques are limited in spatial resolution and the morphological interpretation highly relies on individual experience and knowledge. In this study, we propose a non-destructive technique, Raman microspectroscopy, to discriminate fibrotic changes of collagen type I based on a molecular biomarker. The changes of the secondary structure of collagen type I can be identified by spectral deconvolution, which potentially can provide an automatic diagnosis for fibrotic tissues in the clinical applicaion.

An oral phenylacrylic acid derivative suppressed hepatic stellate cell activation and ameliorated liver fibrosis by blocking TGF-β1 signalling

BACKGROUND AND AIMS

Liver fibrosis is an excessive wound-healing response governed by activated hepatic stellate cells (HSCs). To date, there is no drug available for liver fibrosis. Although ferulic acid (FA) has multiple pharmacological functions, its anti-hepatic fibrosis activity is weak. Based on the activity modification of the FA structure, we synthesized a series of phenylacrylic derivatives and found a superior compound, FA11. In this study, we investigated its antifibrotic effect and mechanism.

METHODS

Activated HSC and CCl₄ -induced mouse liver fibrosis were established and followed by FA11 treatment. Cell viability was measured by CCK-8 assay. Apoptosis and cell cycle analysis were conducted by flow cytometry. Western blot and Real-time qPCR were used to examine the expression of fibrotic and M1/M2-type macrophages markers. Degree of liver fibrosis was shown by histological staining.

RESULTS

In vitro, FA11 inhibited TGF-β1-induced LX-2 proliferation and led to apoptosis and cycle arrest. Furthermore, elevation of fibrotic markers in TGF-β1-induced LX-2 and primary activated HSC was reversed by FA11. In vivo, FA11 administration alleviated collagen deposition and blocked HSC activation and epithelial-mesenchymal transition (EMT). Additionally, FA11 reduced macrophage infiltration in fibrotic liver and prevented macrophage polarization to a profibrotic phenotype. Meanwhile, the systemic toxicity of CCl₄ was also ameliorated by FA11. Mechanistically, FA11 reversed the phosphorylation of canonical and noncanonical TGF-β1 signalling, as well as FGFR1 signalling.

CONCLUSIONS

We reported an oral phenylacrylic acid derivative, FA11, which showed excellent antifibrotic activity and was expected to be an anti-hepatic fibrosis candidate.

Circ_0027470 promotes cadmium exposure-induced prostatic fibrosis via sponging miRNA-1236-3p and stimulating SHH signaling pathway

Cadmium (Cd) is a toxic heavy metal pollutant and serves as an important environmental endocrine-disrupting chemical. Cd exposure is believed to can enhance the risks of age-related disorders including benign prostatic hyperplasia (BPH). This study was to investigate the harms of Cd exposure on mice prostate and human nonmalignant prostate epithelial RWPE-1 cells. Mice prostate fibrosis was evaluated by visualizing the prostatic collagen deposition via Masson and Sirius red staining, and detecting the content of hydroxyproline. Additionally, the epithelial-mesenchymal transition (EMT), primary ciliogenesis and SHH signaling pathways in both mice prostate and RWPE-1 cells were evaluated. It was found that Cd exposure stimulated prostatic collagen deposition, EMT and primary ciliogenesis, as well as enhanced the circ_0027470 level and reduced the miRNA-1236-3p level. Circ_0027470 functioned as a sponge of miRNA-1236-3p, which had the inhibiting target of SHH. The whole results showed that circ_0027470 promoted Cd exposure-induced prostatic fibrosis via sponging miRNA-1236-3p and subsequently stimulating SHH signaling pathway. This study shed a light on a novel molecular mechanism involved in circRNA for Cd exposure-induced prostate deficits.

Up-regulation of the human-specific CHRFAM7A gene protects against renal fibrosis in mice with obstructive nephropathy

Renal fibrosis is a major factor in the progression of chronic kidney diseases. Obstructive nephropathy is a common cause of renal fibrosis, which is also accompanied by inflammation. To explore the effect of human-specific CHRFAM7A expression, an inflammation-related gene, on renal fibrosis during obstructive nephropathy, we studied CHRFAM7A transgenic mice and wild type mice that underwent unilateral ureteral obstruction (UUO) injury. Transgenic overexpression of CHRFAM7A gene inhibited UUO-induced renal fibrosis, which was demonstrated by decreased fibrotic gene expression and collagen deposition. Furthermore, kidneys from transgenic mice had reduced TGF-β1 and Smad2/3 expression following UUO compared with those from wild type mice with UUO. In addition, the overexpression of CHRFAM7A decreased release of inflammatory cytokines in the kidneys of UUO-injured mice. In vitro, the overexpression of CHRFAM7A inhibited TGF-β1-induced increase in expression of fibrosis-related genes in human renal tubular epithelial cells (HK-2 cells). Additionally, up-regulated expression of CHRFAM7A in HK-2 cells decreased TGF-β1-induced epithelial-mesenchymal transition (EMT) and inhibited activation f TGF-β1/Smad2/3 signalling pathways. Collectively, our findings demonstrate that overexpression of the human-specific CHRFAM7A gene can reduce UUO-induced renal fibrosis by inhibiting TGF-β1/Smad2/3 signalling pathway to reduce inflammatory reactions and EMT of renal tubular epithelial cells.

Coal dust nanoparticles induced pulmonary fibrosis by promoting inflammation and epithelial-mesenchymal transition via the NF-κB/NLRP3 pathway driven by IGF1/ROS-mediated AKT/GSK3β signals

Pneumoconiosis is the most common and serious disease among coal miners. In earlier work on this subject, we documented that coal dust (CD) nanoparticles (CD-NPs) induced pulmonary fibrosis (PF) more profoundly than did CD micron particles (CD-MPs), but the mechanism has not been thoroughly studied. Based on the GEO database, jveen, STRING, and Cytoscape tools were used to screen hub genes regulating PF. Particle size distribution of CD were analyzed with Malvern nanoparticle size potentiometer. Combining 8 computational methods, we found that IGF1, POSTN, MMP7, ASPN, and CXCL14 may act as hub genes regulating PF. Based on the high score of IGF1 and its important regulatory role in various tissue fibrosis, we selected it as the target gene in this study. Activation of the IGF1/IGF1R axis promoted CD-NPs-induced PF, and inhibition of the axis activation had the opposite effect in vitro and in vivo. Furthermore, activation of the IGF1/IGF1R axis induced generation of reactive oxygen species (ROS) to promote epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs) to accelerate PF. High-throughput gene sequencing based on lung tissue suggested that cytokine-cytokine receptor interaction and the NF-kB signaling pathway play a key role in PF. Also, ROS induced inflammation and EMT by the activation of the NF-kB/NLRP3 axis to accelerate PF. ROS can induce the activation of AKT/GSK3β signaling, and inhibition of it can inhibit ROS-induced inflammation and EMT by the NF-kB/NLRP3 axis, thereby inhibiting PF. CD-NPs induced PF by promoting inflammation and EMT via the NF-κB/NLRP3 pathway driven by IGF1/ROS-mediated AKT/GSK3β signals. This study provides a valuable experimental basis for the prevention and treatment of coal workers' pneumoconiosis. Illustration of the overall research idea of this study: IGF1 stimulates coal dust nanoparticles induced pulmonary fibrosis by promoting inflammation and EMT via the NF-κB/NLRP3 pathway driven by ROS-mediated AKT/GSK3β signals.

Recent Update on the Anti-Inflammatory Activities of Propolis

In recent years, research has demonstrated the efficacy propolis as a potential raw material for pharmaceuticals and nutraceuticals. There is limited report detailing the mechanisms of action of propolis and its bioactive compounds in relation to their anti-inflammatory properties. Thus, the aim of the present review is to examine the latest experimental evidence (2017-2022) regarding the anti-inflammatory properties of propolis. A systematic scoping review methodology was implemented. After applying the exclusion criteria, a total of 166 research publications were identified and retrieved from Scopus, Web of Science, and Pubmed. Several key themes related to the anti-inflammatory properties of propolis were subsequently identified, namely in relation to cancers, oral health, metabolic syndrome, organ toxicity and inflammation, immune system, wound healing, and pathogenic infections. Based on the latest experimental evidence, propolis is demonstrated to possess various mechanisms of action in modulating inflammation towards the regulatory balance and anti-inflammatory environment. In general, we summarize that propolis acts as an anti-inflammatory substance by inhibiting and downregulating TLR4, MyD88, IRAK4, TRIF, NLRP inflammasomes, NF-κB, and their associated pro-inflammatory cytokines such as IL-1β, IL-6, IFN-γ, and TNF-α. Propolis also reduces the migration of immune cells such as macrophages and neutrophils, possibly by downregulating the chemokines CXCL9 and CXCL10.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

The Expression of Follistatin-like 1 Protein Is Associated with the Activation of the EMT Program in Sjögren’s Syndrome

Background: The activation of the epithelial to mesenchymal transition (EMT) program is a pathological response of the Sjögren’s syndrome (SS) salivary glands epithelial cells (SGEC) to chronic inflammation. Follistatin-like 1 protein (FSTL1) is a secreted glycoprotein induced by transforming growth factor-β1 (TGF-β1), actively involved in the modulation of EMT. However, the role of FSTL1 in the EMT program activation in SS has not yet been investigated. Methods: TGF-β1-stimulated healthy human SGEC, SS SGEC, and SS salivary glands (SGs) biopsies were used to assess the effect of FSTL1 on the activation of the EMT program. FSTL1 gene activity was inhibited by the siRNA gene knockdown technique. Results: Here we reported that FSTL1 is up-regulated in SS SGs tissue in a correlated manner with the inflammatory grade. Blockage of FSTL1 gene expression by siRNA negatively modulates the TGF-β1-induced EMT program in vitro. We discovered that these actions were mediated through the modulation of the SMAD2/3-dependent EMT signaling pathway. Conclusions: Our data suggest that the TGF-β1-FSTL1-SMAD2/3 regulatory circuit plays a key role in the regulation of EMT in SS and targeting FSTL1 may be a strategy for the treatment of SGs EMT-dependent fibrosis.

Mesenchymal Stem Cell-Derived Exosomes in Cardioprotection: A Novel Application to Prevent Myocardial Injury

Perioperative myocardial injury is a common complication caused by major surgery. Many pharmacological and nonpharmacological studies have investigated perioperative cardioprotection. However, the methods are insufficient to meet the increasing clinical needs for cardioprotection. The application of Mesenchymal Stem Cell-Derived Exosomes (MSC-Exos) is a novel cell-free therapeutic strategy and has significantly benefitted patients suffering from various diseases. In this review, we comprehensively analyzed the application of MSC-Exos to prevent myocardial infarction/injury by regulating inflammatory reactions, inhibiting cardiomyocyte apoptosis and autophagy, promoting angiogenesis, and mediating cardiac remodeling. Finally, we assessed the therapeutic effects and the challenges associated with the application of MSC-Exos from a clinical perspective.

The role of the tumor microenvironment in colorectal cancer and the potential therapeutic approaches

BACKGROUND

Colorectal cancer (CRC) with a high prevalence is recognized as the fourth most common cause of cancer-related death globally. Over the past decade, there has been growing interest in the network of tumor cells, stromal cells, immune cells, blood vessel cells, and fibroblasts that comprise the tumor microenvironment (TME) to identify new therapeutic interventions.

METHODS

Databases, such as Google Scholar, PubMed, and Scopus, were searched to provide an overview of the recent research progress related to targeting the TME as a novel therapeutic approach.

RESULTS

Tumor microenvironment as a result of the cross talk between these cells may result in either advantages or disadvantages in tumor development and metastasis, affecting the signals and responses from the surrounding cells. Whilst chemotherapy has led to an improvement in CRC patients' survival, the metastatic aspect of the disease remains difficult to avoid.

CONCLUSIONS

The present review emphasizes the structure and function of the TME, alterations in the TME, its role in the incidence and progression of CRC, the effects on tumor development and metastasis, and also the potential of its alterations as therapeutic targets. It should be noted that providing novel studies in this field of research might help us to achieve practical therapeutic strategies based on their interaction.

Tumor necrosis factor-α coordinates with transforming growth factor-β1 to induce epithelial-mesenchymal transition and migration via the NF-κB/NOX4 pathway in bronchial epithelial cells

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is the process by which epithelial cells transform into mesenchymal cells, which plays a significant role in lung fibrotic disease. Transforming growth factor-β1(TGF-β1) is considered to be the most effective EMT inducer. The purpose of this study was to investigate the effect of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) on TGF-β1-induced EMT and the underlying mechanisms in the human bronchial epithelial cell line BEAS-2B.

METHODS

Human bronchial epithelial BEAS-2B cells were treated with TGF-β1 and TNF-α separately or in combination for 24 h, and qRT-PCR, western blotting, immunofluorescence staining, and migration assays were used to investigate the EMT process. Moreover, to further explore the effect of the NF-κB pathway on the EMT process, inhibitor assays (BAY-117082, NF-κB inhibitor), wound healing assays, and western blotting were performed.

RESULTS

The results showed that both cytokines enhanced the transformation of BEAS-2B cells from epithelial to mesenchymal cells. In addition, combined treatment with TNF-α and TGF-β1 further reduced E-cadherin expression, which conversely elevated α-SMA and vimentin mRNA and protein levels. Correspondingly, the migration rate of BEAS-2B cells was also increased. Furthermore, inhibiting the NF-κB signaling pathway blocked the expression of EMT-related markers and NOX4 induced by TGF-β1 and TNF-α, as well as cell migration.

CONCLUSION

Taken together, TNF-α and TGF-β1 cooperatively promoted EMT and cell migration in BEAS-2B cells through the NF-κB/NOX4 signaling pathway.

Sjögren's Syndrome-Related Organs Fibrosis: Hypotheses and Realities

Sjögren's syndrome (SS) is a systemic chronic autoimmune disorder characterized by lymphoplasmacytic infiltration of salivary glands (SGs) and lacrimal glands, causing glandular damage. The disease shows a combination of dryness symptoms found in the oral cavity, pharynx, larynx, and vagina, representing a systemic disease. Recent advances link chronic inflammation with SG fibrosis, based on a molecular mechanism pointing to the epithelial to mesenchymal transition (EMT). The continued activation of inflammatory-dependent fibrosis is highly detrimental and a common final pathway of numerous disease states. The important question of whether and how fibrosis contributes to SS pathogenesis is currently intensely debated. Here, we collect the recent findings on EMT-dependent fibrosis in SS SGs and explore clinical evidence of multi-organ fibrosis in SS to highlight potential avenues for therapeutic investigation.

Oxy210, a Semi-Synthetic Oxysterol, Exerts Anti-Inflammatory Effects in Macrophages via Inhibition of Toll-like Receptor (TLR) 4 and TLR2 Signaling and Modulation of Macrophage Polarization

Inflammatory responses by the innate and adaptive immune systems protect against infections and are essential to health and survival. Many diseases including atherosclerosis, osteoarthritis, rheumatoid arthritis, psoriasis, and obesity involve persistent chronic inflammation. Currently available anti-inflammatory agents, including non-steroidal anti-inflammatory drugs, steroids, and biologics, are often unsafe for chronic use due to adverse effects. The development of effective non-toxic anti-inflammatory agents for chronic use remains an important research arena. We previously reported that oral administration of Oxy210, a semi-synthetic oxysterol, ameliorates non-alcoholic steatohepatitis (NASH) induced by a high-fat diet in APOE*3-Leiden.CETP humanized mouse model of NASH and inhibits expression of hepatic and circulating levels of inflammatory cytokines. Here, we show that Oxy210 also inhibits diet-induced white adipose tissue inflammation in APOE*3-Leiden.CETP mice, evidenced by the inhibition of adipose tissue expression of IL-6, MCP-1, and CD68 macrophage marker. Oxy210 and related analogs exhibit anti-inflammatory effects in macrophages treated with lipopolysaccharide in vitro, mediated through inhibition of toll-like receptor 4 (TLR4), TLR2, and AP-1 signaling, independent of cyclooxygenase enzymes or steroid receptors. The anti-inflammatory effects of Oxy210 are correlated with the inhibition of macrophage polarization. We propose that Oxy210 and its structural analogs may be attractive candidates for future therapeutic development for targeting inflammatory diseases.

Autoimmunity and Cancer-Two Sides of the Same Coin

Autoimmune disease results from the immune response against self-antigens, while cancer develops when the immune system does not respond to malignant cells. Thus, for years, autoimmunity and cancer have been considered as two separate fields of research that do not have a lot in common. However, the discovery of immune checkpoints and the development of anti-cancer drugs targeting PD-1 (programmed cell death receptor 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) pathways proved that studying autoimmune diseases can be extremely helpful in the development of novel anti-cancer drugs. Therefore, autoimmunity and cancer seem to be just two sides of the same coin. In the current review, we broadly discuss how various regulatory cell populations, effector molecules, genetic predisposition, and environmental factors contribute to the loss of self-tolerance in autoimmunity or tolerance induction to cancer. With the current paper, we also aim to convince the readers that the pathways involved in cancer and autoimmune disease development consist of similar molecular players working in opposite directions. Therefore, a deep understanding of the two sides of immune tolerance is crucial for the proper designing of novel and selective immunotherapies.

Schisandrol A, the main active ingredient of Schisandrae Chinensis Fructus, inhibits pulmonary fibrosis through suppression of the TGF-β signaling pathway as revealed by UPLC-Q-TOF/MS, network pharmacology and experimental verification

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis decoction derived from the book of Waitai Miyao (Tao Wang, Tang dynasty) is often used in the treatment of idiopathic pulmonary fibrosis (IPF), which is included in the Grand Ceremony of Chinese formulae (Huairen Peng, 1994). Schisandrae Chinensis Fructus (Sch) is one of the most important herbs in this formula. According to the "Shennong's Herbal Classicherbal" of the Han Dynasty, Sch has sour taste, warm nature, which has the effect of tonifying qi and curing cough. In addition, according to the "Compendium of Materia Medica" of the Ming Dynasty, Sch is used to treat cough and asthma, which has the effect of moistening the lung and tonifying the kidney. However, the active ingredients of Sch absorption into the plasma and its pharmacological mechanism of treatment for IPF still remained unclear.

AIM OF THE STUDY

Our research aimed at identifying the absorbed active ingredients and metabolized of Sch in rat plasma and the mechanism of anti-IPF based on serum pharmacochemistry.

MATERIALS AND METHODS

First, the rats were divided into control group and Sch group. Sch sample was orally administrated to the rats for seven days. The blood samples were drawn into an Eppendorf tube after the last dosing. The ultrahigh performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) was applied to identify the absorption components and metabolites of Sch in rat plasma. Second, the network pharmacology combined with molecular docking analysis was further investigated to illuminate its potential mechanism of treatment for IPF by the biological targets regulating related pathways. Finally, the mechanism of action was verified by experimental in vitro and in vivo.

RESULTS

A total of 78 compounds, consist of 13 prototype lignans and 65 metabolites (including isomers) were identified. Network pharmacology study and molecular docking analysis indicated that schisandrol A (L1) play an anti-fibrosis role by regulating the TGF-β signaling pathway. Experimental in vitro and in vivo verified that the schisandrol A could inhibiting pulmonary fibrosis through TGF-β signaling pathway. The effect and mechanism of schisandrol A inhibiting pulmonary fibrosis were reported for the first time.

CONCLUSIONS

In this study, the absorption active ingredients of Sch in rat plasma were combined with the network pharmacology investigation and experimental in vitro and in vivo to elucidate its biological mechanism of treatment for IPF. The results provided a theoretical support for understanding the bioactive compounds and the pharmacological mechanism of Sch.

The Synergistic Cooperation between TGF-β and Hypoxia in Cancer and Fibrosis

Transforming growth factor β (TGF-β) is a multifunctional cytokine regulating homeostasis and immune responses in adult animals and humans. Aberrant and overactive TGF-β signaling promotes cancer initiation and fibrosis through epithelial–mesenchymal transition (EMT), as well as the invasion and metastatic growth of cancer cells. TGF-β is a key factor that is active during hypoxic conditions in cancer and is thereby capable of contributing to angiogenesis in various types of cancer. Another potent role of TGF-β is suppressing immune responses in cancer patients. The strong tumor-promoting effects of TGF-β and its profibrotic effects make it a focus for the development of novel therapeutic strategies against cancer and fibrosis as well as an attractive drug target in combination with immune regulatory checkpoint inhibitors. TGF-β belongs to a family of cytokines that exert their function through signaling via serine/threonine kinase transmembrane receptors to intracellular Smad proteins via the canonical pathway and in combination with co-regulators such as the adaptor protein and E3 ubiquitin ligases TRAF4 and TRAF6 to promote non-canonical pathways. Finally, the outcome of gene transcription initiated by TGF-β is context-dependent and controlled by signals exerted by other growth factors such as EGF and Wnt. Here, we discuss the synergistic cooperation between TGF-β and hypoxia in development, fibrosis and cancer.

Bronchoalveolar-Lavage-Derived Fibroblast Cell Line (B-LSDM7) as a New Protocol for Investigating the Mechanisms of Idiopathic Pulmonary Fibrosis

Background: The use of BAL to study ILDs has improved our understanding of IPF pathogenesis. BAL fluid is routinely collected and can be considered a clinical and research tool. The procedure is well tolerated and minimally invasive. No specific cell lines from BAL or immortalized cell lines from IPF patients are available commercially. A method to quickly isolate and characterize fibroblasts from BAL is an unmet research need. Materials and methods: Here we describe a new protocol by which we isolated a cell line from IPF. The cell line was expanded in vitro and characterized phenotypically, morphologically and functionally. Results: This culture showed highly filamentous cells with an evident central nucleus. From the phenotypic point of view, this cell line displays fibroblast/myofibroblast-like features including expression of alpha-SMA, vimentin, collagen type-1 and fibronectin. The results showed high expression of ROS in these cells. Oxidative stress invariably promotes extracellular matrix expression in lung diseases directly or through over-production of pro-fibrotic growth factors. Conclusions: Our protocol makes it possible to obtain fibroblasts BAL that is a routine non-invasive method that offers the possibility of having a large sample of patients. Standardized culture methods are important for a reliable model for testing molecules and eventual novel development therapeutic targets.

E-Cadherin Signaling in Salivary Gland Development and Autoimmunity

E-cadherin, the major epithelial cadherin, is located in regions of cell–cell contact known as adherens junctions. E-cadherin contributes to the maintenance of the epithelial integrity through homophylic interaction; the cytoplasmic tail of E-cadherin directly binds catenins, forming a dynamic complex that regulates several intracellular signal transduction pathways, including epithelial-to-mesenchymal transition (EMT). Recent progress uncovered a novel and critical role for this adhesion molecule in salivary gland (SG) development and in SG diseases. We summarize the structure and regulation of the E-cadherin gene and transcript in view of the role of this remarkable protein in SG morphogenesis, focusing, in the second part of the review, on altered E-cadherin expression in EMT-mediated SG autoimmunity.

Pigment Epithelia of the Eye: Cell-Type Conversion in Regeneration and Disease

Pigment epithelial cells (PECs) of the retina (RPE), ciliary body, and iris (IPE) are capable of altering their phenotype. The main pathway of phenotypic switching of eye PECs in vertebrates and humans in vivo and/or in vitro is neural/retinal. Besides, cells of amphibian IPE give rise to the lens and its derivatives, while mammalian and human RPE can be converted along the mesenchymal pathway. The PECs’ capability of conversion in vivo underlies the lens and retinal regeneration in lower vertebrates and retinal diseases such as proliferative vitreoretinopathy and fibrosis in mammals and humans. The present review considers these processes studied in vitro and in vivo in animal models and in humans. The molecular basis of conversion strategies in PECs is elucidated. Being predetermined onto- and phylogenetically, it includes a species-specific molecular context, differential expression of transcription factors, signaling pathways, and epigenomic changes. The accumulated knowledge regarding the mechanisms of PECs phenotypic switching allows the development of approaches to specified conversion for many purposes: obtaining cells for transplantation, creating conditions to stimulate natural regeneration of the retina and the lens, blocking undesirable conversions associated with eye pathology, and finding molecular markers of pathology to be targets of therapy.

Ketamine Induced Bladder Fibrosis Through MTDH/P38 MAPK/EMT Pathway

Purpose: Ketamine is an anesthetic in clinical, but it has also been used as an abusing drug due to its low price and hallucinogenic effects. It is proved that ketamine abusing would cause multiple system damage including the urinary system, which is called ketamine-induced cystitis (KIC). Bladder fibrosis is late stage in KIC and threaten abusers’ life. This study aimed to investigate the molecular mechanism of ketamine-induced bladder fibrosis.

Methods: Female Sprague Dawley (SD) rats were randomly divided into 3 groups. 2 groups were treated with tail vein injection of ketamine (25 mg/kg/day, 50 mg/kg/day ketamine hydrochloride solution, respectively) for 12 weeks, whereas the control group was treated with normal saline solution. In each group, rat bladders were extracted and samples were examined for pathological and morphological alterations via hematoxylin and eosin (HE) staining, Masson’s trichrome staining and immunohistochemistry (IHC). SV-HUC-1 cells were treated with different concentrations of ketamine solution (0, 0.1, 0.5, 1 mmol/L). Rat bladder and SV-HUC-1 cells were extracted protein and RNA for Western blot and RT-PCR detection. Metadherin (MTDH) siRNAs and overexpression plasmids were used to knock down and overexpress the relative genes. P38 mitogen-activated protein kinase (MAPK) inhibitor was utilized to inhibit the MAPK pathway.

Results: Rats in the ketamine group exhibited fibrosis compared to rats of the control group and fibrosis were also markedly upregulated in SV-HUC-1 cells after treated with ketamine, which were ketamine concentration-dependent. After treating with ketamine in SV-HUC-1 cells, there was an increase expression of MTDH, epithelial-mesenchymal transition (EMT) markers, P38 MAPK. MTDH knockdown would suppresses P38 MAPK/EMT pathway to inhibit fibrosis, however, MTDH overexpression could promote the pathway in SV-HUC-1 cells.

Conclusion: In rats and SV-HUC-1 cells ketamine-treated models, MTDH can regulate EMT through the P38 MAPK pathway to regulate the process of bladder fibrosis.

The exosome-circ_0001359 derived from cigarette smoke exposed-prostate stromal cells promotes epithelial cells collagen deposition and primary ciliogenesis

Cigarettes consumption is continued to be popular. We found that cigarette smoke (CS) exposure promoted prostatic fibrosis. In this study, human prostate epithelial RWPE-1 cells were co-cultured with exosomes derived from CS exposed-WPMY-1 cells (CS-WPMY-1-exo). The collagen deposition, primary ciliogenesis, epithelial-mesenchymal transition (EMT) and transforming growth factor (TGF)-β1 level of RWPE-1 were evaluated. The circRNAs profiles of WPMY-1-exo were explored by high-throughput RNA sequencing. It was found that CS-WPMY-1-exo significantly promoted RWPE-1 collagen deposition, EMT and primary ciliogenesis. There were 17 differentially expressed (DE) circRNAs (including circ_0001359) between CS-WPMY-1-exo and the negative control. Functional enrichment analyses showed that the DE circRNAs played important roles in ciliary basal body, spindle microtubule and TGF-β signaling pathway. Circ_0001359 siRNA attenuated CS-WPMY-1 induced RWPE-1 cells collagen deposition, EMT and primary ciliogenesis, as well as inhibited the level of TGF-β1. The whole results showed that circ_0001359 derived from CS-WPMY-1-exo contributed to prostatic fibrosis via stimulating epithelial cells phenotypes changes and collagen deposition.

Cadherin Signaling in Cancer and Autoimmune Diseases

Cadherins mediate cell–cell adhesion through a dynamic process that is strongly dependent on the cellular context and signaling. Cadherin regulation reflects the interplay between fundamental cellular processes, including morphogenesis, proliferation, programmed cell death, surface organization of receptors, cytoskeletal organization, and cell trafficking. The variety of molecular mechanisms and cellular functions regulated by cadherins suggests that we have only scratched the surface in terms of clarifying the functions mediated by these versatile proteins. Altered cadherins expression is closely connected with tumorigenesis, epithelial–mesenchymal transition (EMT)-dependent fibrosis, and autoimmunity. We review the current understanding of how cadherins contribute to human health and disease, considering the mechanisms of cadherin involvement in diseases progression, as well as the clinical significance of cadherins as therapeutic targets.

1β-Hydroxyalantolactone from Inulae Flos alleviated the progression of pulmonary fibrosis via inhibiting JNK/FOXO1/NF-κB pathway

Inulae Flos was widely distributed throughout Europe, Africa, and Asia, and was commonly used as a folk medicine in clinic for treating various respiratory diseases, including cough, asthma, bronchitis, pulmonary fibrosis, and pneumonia. However, the ingredients responsible for the pharmacology effects of I. Flos and the underlying mechanisms remain unclear. In this study, the effects of 16 known sesquiterpene lactones and flavonoids from I. Flos on TGF-β1-induced fibroblast activation were assessed by phenotypic high-content screening. Among those sixteen compounds, 1β-hydroxy alantolactone (HAL), the main characteristic sesquiterpene lactone from I. Flos, exhibited remarkable inhibitory activity. The further studies showed that HAL significantly inhibited the proliferation and induced the apoptosis of human fibroblast cell lines HELF and MRC-5 in a concentration-dependent manner. It also reduced intracellular ROS production, suppressed the mRNA expressions of E-cad, TGF-β1, Smad3, Col I, α-SMA and TNF-α, and downregulated protein expressions of α-SMA and F-actin. Furthermore, HAL significantly reduced the levels of HA, LN, PC-III and IV-C in serum, TNF-α and IL-6 in BALF, and TGF-β1, HYP and Col I in lung tissues of bleomycin (BLM)-treated rats. HAL significantly downregulated the expressions of p-JNK, FOXO1, p-p65, α-SMA, p-smad3 and Col I but upregulated p-FOXO1, which could be reversed by JNK agonist anisomycin. These results demonstrated that HAL induced the apoptosis of lung fibroblast cells activated by TGF-β1 and improved BLM-induced lung fibrosis in rats via inhibiting JNK/FOXO1/NF-κB pathway.

Epithelial Mesenchymal Transition and its transcription factors

Epithelial–mesenchymal transition or EMT is an extremely dynamic process involved in conversion of epithelial cells into mesenchymal cells, stimulated by an ensemble of signaling pathways, leading to change in cellular morphology, suppression of epithelial characters and acquisition of properties such as enhanced cell motility and invasiveness, reduced cell death by apoptosis, resistance to chemotherapeutic drugs etc. Significantly, EMT has been found to play a crucial role during embryonic development, tissue fibrosis and would healing, as well as during cancer metastasis. Over the years, work from various laboratories have identified a rather large number of transcription factors (TFs) including the master regulators of EMT, with the ability to regulate the EMT process directly. In this review, we put together these EMT TFs and discussed their role in the process. We have also tried to focus on their mechanism of action, their interdependency, and the large regulatory network they form. Subsequently, it has become clear that the composition and structure of the transcriptional regulatory network behind EMT probably varies based upon various physiological and pathological contexts, or even in a cell/tissue type-dependent manner.

Epoxyeicosatrienoic Acids and Fibrosis: Recent Insights for the Novel Therapeutic Strategies

Organ fibrosis often ends in eventual organ failure and leads to high mortality. Although researchers have identified many effector cells and molecular pathways, there are few effective therapies for fibrosis to date and the underlying mechanism needs to be examined and defined further. Epoxyeicosatrienoic acids (EETs) are endogenous lipid metabolites of arachidonic acid (ARA) synthesized by cytochrome P450 (CYP) epoxygenases. EETs are rapidly metabolized primarily via the soluble epoxide hydrolase (sEH) pathway. The sEH pathway produces dihydroxyeicosatrienoic acids (DHETs), which have lower activity. Stabilized or increased EETs levels exert several protective effects, including pro-angiogenesis, anti-inflammation, anti-apoptosis, and anti-senescence. Currently, intensive investigations are being carried out on their anti-fibrotic effects in the kidney, heart, lung, and liver. The present review provides an update on how the stabilized or increased production of EETs is a reasonable theoretical basis for fibrosis treatment.

Epigenetic regulation in fibrosis progress

Fibrosis, a common process of chronic inflammatory diseases, is defined as a repair response disorder when organs undergo continuous damage, ultimately leading to scar formation and functional failure. Around the world, fibrotic diseases cause high mortality, unfortunately, with limited treatment means in clinical practice. With the development and application of deep sequencing technology, comprehensively exploring the epigenetic mechanism in fibrosis has been allowed. Extensive remodeling of epigenetics controlling various cells phenotype and molecular mechanisms involved in fibrogenesis was subsequently verified. In this review, we summarize the regulatory mechanisms of DNA methylation, histone modification, noncoding RNAs (ncRNAs) and N6-methyladenosine (m6A) modification in organ fibrosis, focusing on heart, liver, lung and kidney. Additionally, we emphasize the diversity of epigenetics in the cellular and molecular mechanisms related to fibrosis. Finally, the potential and prospect of targeted therapy for fibrosis based on epigenetic is discussed.