Baicalein attenuates bleomycin-induced pulmonary fibrosis in rats through inhibition of miR-21

Mechanisms of Bleomycin-induced Lung Fibrosis: A Review of Therapeutic Targets and Approaches

Pulmonary toxicity is a serious side effect of some specific anticancer drugs. Bleomycin is a well-known anticancer drug that triggers severe reactions in the lungs. It is an approved drug that may be prescribed for the treatment of testicular cancers, Hodgkin's and non-Hodgkin's lymphomas, ovarian cancer, head and neck cancers, and cervical cancer. A large number of experimental studies and clinical findings show that bleomycin can concentrate in lung tissue, leading to massive oxidative stress, alveolar epithelial cell death, the proliferation of fibroblasts, and finally the infiltration of immune cells. Chronic release of pro-inflammatory and pro-fibrotic molecules by immune cells and fibroblasts leads to pneumonitis and fibrosis. Both fibrosis and pneumonitis are serious concerns for patients who receive bleomycin and may lead to death. Therefore, the management of lung toxicity following cancer therapy with bleomycin is a critical issue. This review explains the cellular and molecular mechanisms of pulmonary injury following treatment with bleomycin. Furthermore, we review therapeutic targets and possible promising strategies for ameliorating bleomycin-induced lung injury.

Therapeutic effects of flavonoids on pulmonary fibrosis: A preclinical meta-analysis

BACKGROUND

The efficacy of flavonoid supplementation in animal models of pulmonary fibrosis has been demonstrated.

PURPOSE

We conducted a systematic review and meta-analysis to evaluate the efficacy and underlying mechanisms of flavonoids in animal models of bleomycin-induced pulmonary fibrosis.

STUDY DESIGN

Relevant studies (n = 45) were identified from English- and Chinese-language databases from the inception of the database until October 2023.

METHODS

Methodological quality was evaluated using the SYRCLE risk of bias tool. Statistical analyses were conducted using RevMan 5.3 and Stata 17.0. Lung inflammation and fibrosis score were the primary outcome indicators.

RESULTS

Flavonoids can alleviate pathological changes in the lungs. The beneficial effects of flavonoids on pulmonary fibrosis likely relate to their inhibition of inflammatory responses, restoration of oxidative and antioxidant homeostasis, and regulation of fibroblast proliferation, migration, and activation by transforming growth factor β1/mothers against the decapentaplegic homologue/AMP-activated protein kinase (TGF-β1/Smad3/AMPK), inhibitor kappa B alpha/nuclear factor-kappa B (IκBα/NF-κB), phosphatidylinositol 3-kinase (PI3K)/AKT, interleukin 6/signal transducer/activator of transcription 3 (IL6/STAT3), and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2-Keap1) pathways.

CONCLUSION

Flavonoids are potential candidate compounds for the prevention and treatment of pulmonary fibrosis. However, extensive preclinical research is necessary to confirm the antifibrotic properties of natural flavonoids.

Flavonoids for treating pulmonary fibrosis: Present status and future prospects

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with an unknown underlying cause. There is no complete cure for IPF; however, two anti-fibrotic agents (Nintedanib and pirfenidone) are approved by the USFDA to extend the patient's life span. Therefore, alternative therapies supporting the survival of fibrotic patients have been studied in recent literature. The abundance of phenolic compounds, particularly flavonoids, has gathered attention due to their potential health benefits. Various flavonoids, like naringin, quercetin, baicalin, baicalein, puerarin, silymarin, and kaempferol, exhibit anti-inflammatory and anti-oxidant properties, which help decrease lung fibrosis. Various databases, including PubMed, EBSCO, ProQuest, and Scopus, as well as particular websites, such as the World Health Organisation and the National Institutes of Health, were used to conduct a literature search. Several mechanisms of action of flavonoids are reported with the help of in vivo and cell line studies emphasizing their ability to modulate oxidative stress, inflammation, and fibrotic processes in the lungs. They are reported for the restoration of biomarkers like hydroxyproline, cytokines, superoxide dismutase, malondialdehyde and others associated with IPF and for modulating various pathways responsible for the progression of pulmonary fibrosis. Yet, flavonoids have some drawbacks, such as poor solubility, challenging drug loading, stability issues, and scarce bioavailability. Therefore, novel formulations of flavonoids are explored, including liposomes, solid lipid microparticles, polymeric nanoparticles, nanogels, and nanocrystals, to enhance the therapeutic efficacy of flavonoids in pulmonary fibrosis. This review focuses on the role of flavonoids in mitigating idiopathic pulmonary fibrosis, their mode of action and novel formulations.

Silica nanoparticles triggered epithelial ferroptosis via miR-21-5p/GCLM signaling to contribute to fibrogenesis in the lungs

The toxicity of silica nanoparticles (SiNPs) to lung is known. We previously demonstrated that exposure to SiNPs promoted pulmonary impairments, but the precise pathogenesis remains elucidated. Ferroptosis has now been identified as a unique form of oxidative cell death, but whether it participated in SiNPs-induced lung injury remains unclear. In this work, we established a rat model with sub-chronic inhalation exposure of SiNPs via intratracheal instillation, and conducted histopathological examination, iron detection, and ferroptosis-related lipid peroxidation and protein assays. Moreover, we evaluated the effect of SiNPs on epithelial ferroptosis, possible mechanisms using in vitro-cultured human bronchial epithelial cells (16HBE), and also assessed the ensuing impact on fibroblast activation for fibrogenesis. Consequently, fibrotic lesions occurred in the rat lungs, concomitantly by enhanced lipid peroxidation, iron overload, and ferroptosis. Consistently, the in vitro data showed SiNPs triggered oxidative stress and caused the accumulation of lipid peroxides, resulting in ferroptosis. Importantly, the mechanistic investigation revealed miR-21-5p as a key player in the epithelial ferroptotic process induced by SiNPs via targeting GCLM for GSH depletion. Of note, ferrostatin-1 could greatly suppress ferroptosis and alleviate epithelial injury and ensuing fibroblast activation by SiNPs. In conclusion, our findings first revealed SiNPs triggered epithelial ferroptosis through miR-21-5p/GCLM signaling and thereby promoted fibroblast activation for fibrotic lesions, and highlighted the therapeutic potential of inhibiting ferroptosis against lung impairments upon SiNPs exposure.

Monomeric compounds from natural products for the treatment of pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is the end stage of lung injury and chronic lung diseases that results in diminished lung function, respiratory failure, and ultimately mortality. Despite extensive research, the pathogenesis of this disease remains elusive, and effective therapeutic options are currently limited, posing a significant clinical challenge. In addition, research on traditional Chinese medicine and naturopathic medicine is hampered by several complications due to complex composition and lack of reference compounds. Natural product monomers, possessing diverse biological activities and excellent safety profiles, have emerged as potential candidates for preventing and treating PF. The effective anti-PF ingredients identified can be generally divided into flavonoids, saponins, polysaccharides, and alkaloids. Specifically, these monomeric compounds can attenuate inflammatory response, oxidative stress, and other physiopathological processes of the lung through many signaling pathways. They also improve pulmonary factors. Additionally, they ameliorate epithelial-mesenchymal transition (EMT) and fibroblast-myofibroblast transdifferentiation (FMT) by regulating multiple signal amplifiers in the lungs, thereby mitigating PF. This review highlights the significant role of monomer compounds derived from natural products in reducing inflammation, oxidative stress, and inhibiting EMT process. The article provides comprehensive information and serves as a solid foundation for further exploration of new strategies to harness the potential of botanicals in the treatment of PF.

Anti-ROS and NIR-II-Responsive Hyaluronic Acid Microneedle Loaded With Baicalin Nanoparticles for Treatment of Psoriasis

In this work, a natural medicine, baicalin, is designed for the treatment of psoriasis with the aid of hyaluronic acid (HA)-based MNs patches. This is also to improve the solubility of baicalin and increase its residence time in infected part, which is made into nanoparticles by complexation with humic acid and Eu2+. The baicalin nanoparticles loaded-MNs exhibit satisfactory rigidity, minimum injury, and controlled drug delivery. The anti-reactive oxygen species (anti-ROS) and anti-inflammatory action are verified by the effective scavenging oxygen and nitrogen radicals. In addition, the loading of baicalin nanoparticles brings remarkable photothermic effect to the MNs, enabling the device to release a controlled drug under near-infrared region II (NIR-II) laser irradiation. With the aid of NIR-II laser, the baicalin-mediated treatment of psoriasis is significantly improved by expediting radical scavenging and suppressing inflammation. The design of baicalin MNs provides a new idea for the treatment of chronic disease.

Baicalein attenuates bleomycin-induced lung fibroblast senescence and lung fibrosis through restoration of Sirt3 expression

CONTEXT

Fibroblast senescence was reported to contribute to the pathological development of idiopathic pulmonary fibrosis (IPF), and baicalein is reported to attenuate IPF.

OBJECTIVE

This study explores whether baicalein attenuates lung fibrosis by regulating lung fibroblast senescence.

MATERIALS AND METHODS

Institute of Cancer Research (ICR) mice were randomly assigned to control, bleomycin (BLM), baicalein and BLM + baicalein groups. Lung fibrosis was established by a single intratracheal dose of BLM (3 mg/kg). The baicalein group received baicalein orally (100 mg/kg/day). Sirtuin 3 (Sirt3) siRNA (50 μg) was injected through the tail vein once a week for 2 weeks to explore its effect on the anti-pulmonary fibrosis of baicalein.

RESULTS

BLM-treated mice exhibited obvious lung fibrosis and fibroblast senescence by showing increased levels of collagen deposition (27.29% vs. 4.14%), hydroxyproline (208.05 vs. 40.16 ng/mg), collagen I (25.18 vs. 9.15 μg/mg), p53, p21, p16, MCP-1, PAI-1, TNF-α, MMP-10 and MMP-12 in lung tissues, which were attenuated by baicalein. Baicalein also mitigated BLM-mediated activation of TGF-β1/Smad signalling pathway. Baicalein restored the BLM-induced downregulation of Sirt3 expression in lung tissues and silencing of Sirt3 abolished the inhibitory role of baicalein against BLM-induced lung fibrosis, fibroblast senescence and activation of TGF-β1/Smad signalling pathway.

CONCLUSIONS

Baicalein preserved the BLM-induced downregulation of lung Sirt3 expression, and thus the suppression of TGF-β1/Smad signalling pathway and lung fibrosis, which might provide an experimental basis for treatment of IPF.

Graph neural networks for the identification of novel inhibitors of a small RNA

MicroRNAs (miRNAs) play a crucial role in post-transcriptional gene regulation and have been implicated in various diseases, including cancers and lung disease. In recent years, Graph Neural Networks (GNNs) have emerged as powerful tools for analyzing graph-structured data, making them well-suited for the analysis of molecular structures. In this work, we explore the application of GNNs in ligand-based drug screening for small molecules targeting miR-21. By representing a known dataset of small molecules targeting miR-21 as graphs, GNNs can learn complex relationships between their structures and activities, enabling the prediction of potential miRNA-targeting small molecules by capturing the structural features and similarity between known miRNA-targeting compounds. The use of GNNs in miRNA-targeting drug screening holds promise for the discovery of novel therapeutic agents and provides a computational framework for efficient screening of large chemical libraries.

Resveratrol mitigates miR-212-3p mediated progression of diesel exhaust-induced pulmonary fibrosis by regulating SIRT1/FoxO3

BACKGROUND

Diesel exhaust (DE) exposure contributes to the progression of chronic respiratory diseases and is associated with dysregulation of microRNA expression. The present study aims to investigate the involvement of miRNAs and target genes in DE-induced lung fibrosis.

METHODS

C57BL/6 mice were divided into three groups. Group 1 mice were exposed to filtered air (Control). Group 2 mice were exposed to DE for 30 min per day, 5 days per week, for 8 weeks (DE). Group 3 mice received DE exposure along with resveratrol on alternate days for the last 2 weeks (DE + RES). Mice were sacrificed to isolate RNA from lung tissue for miRNA microarray profiling. Bronchoalveolar lavage fluid and lung tissues were collected for cell count and biochemical analysis.

RESULTS

DE exposure resulted in differential expression of 28 miRNAs with fold change >2 (p < 0.05). The upregulated miR-212-3p was selected for further analysis. Consensus analysis revealed enrichment of SIRT1 in the FoxO pathway, along with a co-annotation of reduced body weight (p < 0.05). A549 cells transfected with a miR-212-3p inhibitor showed a dose-dependent increase in SIRT1 expression, indicating SIRT1 as a direct target. Treatment with resveratrol restored SIRT1 and miR-212-3p expression and led to a reduction in inflammatory cytokines (p < 0.05). The modulation of SIRT1 correlated negatively with macrophage infiltration, confirming its role in regulating cellular infiltration and lung inflammation. Fibronectin, alpha-SMA, and collagen levels were significantly decreased in DE + RES compared to DE group suggesting modulation of cellular functions and resolution of lung fibrosis. Furthermore, a significant decrease in FoxO3a and TGF-β gene expressions was observed upon resveratrol administration thereby downregulating pro-fibrotic pathway.

CONCLUSIONS

The present study demonstrates resveratrol treatment stabilizes SIRT1 gene expression by attenuating miR-212-3p in DE-exposed mice, leading to downregulation of TGF-β and FoxO3a expressions. The study highlights the therapeutic role of resveratrol in the treatment of DE-induced pulmonary fibrosis.

Baicalin alleviates bleomycin-induced early pulmonary fibrosis in mice via the mitoKATP signaling pathway

Bleomycin (BLM), a frequently employed chemotherapeutic agent, exhibits restricted clinical utility owing to its pulmonary toxicity. Meanwhile, baicalin (BA)-an active ingredient extracted from the roots of Scutellaria baicalensis Georgi -has been shown to alleviate BLM-induced pulmonary fibrosis (PF). Hence, the objective of this study was to examine the protective effects of BA in the context of BLM-induced early PF in mice and elucidate the underlying mechanism(s). We established an in vivo BLM (3.5 mg/kg)-induced PF murine model and in vitro BLM (35 μM)-damaged MLE-12 cell model. On Day 14 of treatment, the levels of fibrosis and apoptosis were evaluated in mouse lungs via hydroxyproline analysis, western blotting (COL1A1, TGF-β, Bax, Bcl-2, cleaved caspase-3), and Masson, immunohistochemical (α-SMA, AIF, Cyto C), and TUNEL staining. Additionally, in vitro, apoptosis was assessed in MLE-12 cells exposed to BLM for 24 h using the Annexin V/PI assay and western blotting (Bax, Bcl-2, cleaved caspase-3, AIF, Cyto C). To elucidate the role of the mitochondrial ATP-sensitive potassium channel (mitoKATP) in the protective effect of BA, we utilised diazoxide (DZX)-a mitoKATP agonist-and 5-hydroxydecanoate sodium (5-HD)-a mitoKATP inhibitor. Results revealed the involvement of mitoKATP in the protective effect of BA in BLM-induced PF. More specifically, mitoKATP activation can attenuate BLM-induced PF progression and mitigate alveolar epithelial type II cell death by reducing mitochondrial ROS, maintaining the mitochondrial membrane potential, and impeding the mitochondrial apoptotic pathway. Collectively, the findings offer pharmacological support to use BA for the treatment or prevention of BLM-induced PF and suggest that mitoKATP might serve as an effective therapeutic target for this condition.

Codium fragile Suppressed Chronic PM2.5-Exposed Pulmonary Dysfunction via TLR/TGF-β Pathway in BALB/c Mice

This study investigated the ameliorating effect of the aqueous extract of Codium fragile on PM2.5-induced pulmonary dysfunction. The major compounds of Codium fragile were identified as palmitic acid, stearic acid, and oleamide using GC/MS2 and hexadecanamide, oleamide, and 13-docosenamide using UPLC-Q-TOF/MSE. Codium fragile improved pulmonary antioxidant system deficit by regulating SOD activities and reducing GSH levels and MDA contents. It suppressed pulmonary mitochondrial dysfunction by regulating ROS contents and mitochondrial membrane potential levels. It regulated the inflammatory protein levels of TLR4, MyD88, p-JNK, p-NF-κB, iNOS, Caspase-1, TNF-α, and IL-1β. In addition, it improved the apoptotic protein expression of BCl-2, BAX, and Caspase-3 and attenuated the fibrous protein expression of TGF-β1, p-Smad-2, p-Smad-3, MMP-1, and MMP-2. In conclusion, this study suggests that Codium fragile might be a potential material for functional food or pharmaceuticals to improve lung damage by regulating oxidative stress inflammation, cytotoxicity, and fibrosis via the TLR/TGF-β1 signaling pathway.

Total sesquiterpenoids from Eupatorium lindleyanum DC. attenuate bleomycin-induced lung fibrosis by suppressing myofibroblast transition

Eupatorium lindleyanum DC. has been used as a functional food in China for a long time. However, the antifibrotic activity of total sesquiterpenoids from Eupatorium lindleyanum DC. (TS-EL) is still unknown. In this study, we discovered that TS-EL reduced the increase in α-smooth muscle actin (α-SMA), type I collagen and fibronectin content, the formation of cell filaments and collagen gel contraction in transforming growth factor-β1-stimulated human lung fibroblasts. Intriguingly, TS-EL did not change the phosphorylation of Smad2/3 and Erk1/2. TS-EL decreased the levels of serum response factor (SRF), a critical transcription factor of α-SMA, and SRF knockdown alleviated the transition of lung myofibroblasts. Furthermore, TS-EL significantly attenuated bleomycin (BLM)-induced lung pathology and collagen deposition and reduced the levels of two profibrotic markers, total lung hydroxyproline and α-SMA. TS-EL also decreased the levels of SRF protein expression in BLM-induced mice. These results suggested that TS-EL attenuates pulmonary fibrosis by inhibiting myofibroblast transition via the downregulation of SRF.

Natural plant resource flavonoids as potential therapeutic drugs for pulmonary fibrosis

Pulmonary fibrosis is an enduring and advancing pulmonary interstitial disease caused by multiple factors that ultimately lead to structural changes in normal lung tissue. Currently, pulmonary fibrosis is a global disease with a high degree of heterogeneity and mortality rate. Nitidine and pirfenidone have been approved for treating pulmonary fibrosis, and the quest for effective therapeutic drugs remains unabated. In recent years, the anti-pulmonary fibrosis properties of natural flavonoids have garnered heightened attention, although further research is needed. In this paper, the resources, structural characteristics, anti-pulmonary fibrosis properties and mechanisms of natural flavonoids were reviewed. We hope to provide potential opportunities for the application of flavonoids in the fight against pulmonary fibrosis.

Tanreqing injection protects against bleomycin-induced pulmonary fibrosis via inhibiting STING-mediated endoplasmic reticulum stress signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Idiopathic pulmonary fibrosis (IPF), characterized by excessive collagen deposition, is a progressive and typically fatal lung disease without effective therapeutic methods. Tanreqing injection (TRQ), a Traditional Chinese Patent Medicine, has been widely used to treat inflammatory respiratory diseases clinically.

AIM OF THE STUDY

The present work aims to elucidate the therapeutic effects and the possible mechanism of TRQ against pulmonary fibrosis.

METHODS

The pulmonary fibrosis murine model were constructed by the intratracheal injection of bleomycin (BLM). 7 days later, TRQ-L (2.6 ml/kg) and TRQ-H (5.2 ml/kg) were administered via intraperitoneal injection respectively for 21 days. The efficacy and underlying molecular mechanism of TRQ were investigated.

RESULTS

Here, we showed that TRQ significantly inhibited BLM-induced lung edema and pulmonary function. TRQ markedly reduced BLM-promoted inflammatory cell infiltration in BALF and inflammatory cytokines release (TNF-α, IL-6, and IL-1β) in serum and lung tissues. Meanwhile, TRQ also alleviated BLM-induced collagen synthesis and deposition. Simultaneously, TRQ attenuated BLM-induced pulmonary fibrosis through regulating the expression of fibrotic hallmarks, manifested by down-regulated α-SMA and up-regulated E-cadherin. Moreover, we found that TRQ significantly prevented STING, p-P65, BIP, p-PERK, p-eIF2α, and ATF4 expression in lung fibrosis mice.

CONCLUSIONS

Taken together, our results indicated that TRQ positively affects inflammatory responses and lung fibrosis by regulating STING-mediated endoplasmic reticulum stress (ERS) signal pathway.

Protective effects of Qing-Re-Huo-Xue formula on bleomycin-induced pulmonary fibrosis through the p53/IGFBP3 pathway

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing lung disease with high mortality. Inflammation and epithelial mesenchymal transformation (EMT) may play an important role in the occurrence and development of IPF. Qing-Re-Huo-Xue formula (QRHXF) has been used clinically by our team for half a century and has obvious therapeutic effects on lung disease. Nevertheless, the role and mechanism of QRHXF in the treatment of IPF have never been studied.

Methods

A mouse pulmonary fibrosis model was established by intratracheal injection of BLM. The effects of QRHXF on the treatment of pulmonary fibrosis were studied by pulmonary function testing, imaging examination, pathological staining, transmission electron microscopy (TEM) observation and mRNA expression. Tandem mass tag (TMT)-based quantitative proteomics was carried out to analyse the lung protein expression profiles between the control (CTL), bleomycin (BLM) and QRHXF (BLM + QRHXF) groups. Immunohistochemistry and qRT-PCR were used to verify the possible existence of drug target proteins and signalling pathways.

Results

The results of pulmonary function, lung pathology and imaging examinations showed that QRHXF could significantly alleviate BLM-induced pulmonary fibrosis in vivo. Additionally, inflammatory cell infiltration and EMT were markedly reduced in BLM-induced PF mice administered QRHXF. Proteomics detected a total of 35 proteins, of which 17 were upregulated and 18 were downregulated. A total of 19 differentially expressed proteins (DEPs) overlapped between the BLM versus CTL groups and the BLM + QRHXF versus BLM groups. The expression of p53 and IGFBP3 was reversed in the QRHXF intervention group, which was verified by immunohistochemistry and qRT-PCR.

Conclusions

QRHXF attenuated BLM-induced pulmonary fibrosis, and regulation of the p53/IGFBP3 pathway might be associated with its efficacy, which holds promise as a novel treatment strategy for pulmonary fibrosis patients.

Graphical Abstract

Nano-baicalein facilitates chemotherapy in breast cancer by targeting tumor microenvironment

Cancer-associated fibroblasts constitute a significant component in the tumor microenvironment, playing a pivotal role in tumor proliferation, invasion, migration, and metastasis. Consequently, therapy combining chemotherapeutic agents with tumor microenvironment (TME) modulators appears to be a promising avenue for cancer treatment. In this paper, a tumor microenvironment-based mPEG-PLGA nanoparticle loaded with baicalein (PMs-Ba) was constructed for the purpose of improving the tumor microenvironment in cases of triple-negative breast cancer. The results demonstrate that, on the one hand, PMs-Ba was able to inhibit the transforming growth factor β(TGF-β) signaling pathway to avoid the activation of cancer-associated fibroblasts (CAFs), thereby influencing the interstitial microenvironment of the tumor. On the other hand, the agent led to an increase in the infiltration of cytotoxic T cells, activating the tumor immune microenvironment. Meanwhile, in the murine breast cancer model, an intravenous injection of PMs-Ba combined with doxorubicin nanoparticles (PMs-ADM) significantly improved the antitumor effectiveness. These results suggest that baicalein encapsulated in nanoparticles may be a promising strategy for modulating the TME and for adjuvant chemotherapy, signifying a potential TME-remodeling nanoformulation that could enhance the antitumor efficacy of nanotherapeutics.

Monomeric compounds from traditional Chinese medicine: New hopes for drug discovery in pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic and irreversible pulmonary disease, and can lead to decreased lung function, respiratory failure and even death. The pathogenesis research and treatment strategy of PF significantly lag behind the medical progress and clinical needs. The treatment of this disease remains a thorny clinical problem, and the effective therapeutic drugs are still limited. Monomeric compounds from traditional Chinese medicine own various biological activities and high safety. They play a broad part in treating diseases and is also a candidate drug for preventing and treating PF. In this paper, we reviewed the mechanism of action and potential value of various anti-PF monomeric compounds from traditional Chinese medicine. These monomeric compounds can attenuate inflammatory response, oxidative stress, epithelial mesenchymal transformation and other processes of lung through many signaling pathways, and inhibit the activation and differentiation of fibroblasts, thus contributing to the treatment of PF. This review can provide new ideas for the development of anti-PF drugs in high efficiency with low toxicity.

Promising Role of the Scutellaria baicalensis Root Hydroxyflavone-Baicalein in the Prevention and Treatment of Human Diseases

Plant roots, due to a high content of natural antioxidants for many years, have been used in herbal medicine. It has been documented that the extract of Baikal skullcap (Scutellaria baicalensis) has hepatoprotective, calming, antiallergic, and anti-inflammatory properties. Flavonoid compounds found in the extract, including baicalein, have strong antiradical activity, which improves overall health and increases feelings of well-being. Plant-derived bioactive compounds with antioxidant activity have for a long time been used as an alternative source of medicines to treat oxidative stress-related diseases. In this review, we summarized the latest reports on one of the most important aglycones with respect to the pharmacological activity and high content in Baikal skullcap, which is 5,6,7-trihydroxyflavone (baicalein).

Baicalein alleviates fibrosis and inflammation in systemic sclerosis by regulating B-cell abnormalities

BACKGROUND

Systemic sclerosis (SSc; also known as "scleroderma") is an autoimmune disorder characterized by extensive fibrosis, vascular changes, and immunologic dysregulation. Baicalein (phenolic flavonoid derived from Scutellaria baicalensis Georgi) has been used to treat the pathological processes of various fibrotic and inflammatory diseases. In this study, we investigated the effect of baicalein on the major pathologic characteristics of SSc: fibrosis, B-cell abnormalities, and inflammation.

METHODS

The effect of baicalein on collagen accumulation and expression of fibrogenic markers in human dermal fibroblasts were analyzed. SSc mice were produced by injecting bleomycin and treated with baicalein (25, 50, or 100 mg/kg). The antifibrotic features of baicalein and its mechanisms were investigated by histologic examination, hydroxyproline assay, enzyme-linked immunosorbent assay, western blotting and flow cytometry.

RESULTS

Baicalein (5-120 μM) significantly inhibited the accumulation of the extracellular matrix and fibroblast activation in transforming growth factor (TGF)-β1- and platelet derived growth factor (PDGF)-induced human dermal fibroblasts, as evidenced by abrogated deposition of total collagen, decreased secretion of soluble collagen, reduced collagen contraction capability and downregulation of various fibrogenesis molecules. In a bleomycin-induced model of dermal fibrosis in mice, baicalein (25-100 mg/kg) restored dermal architecture, ameliorated inflammatory infiltrates, and attenuated dermal thickness and collagen accumulation in a dose-dependent manner. According to flow cytometry, baicalein reduced the proportion of B cells (B220⁺ lymphocytes) and increased the proportion of memory B cells (B220⁺CD27⁺ lymphocytes) in the spleens of bleomycin-induced mice. Baicalein treatment potently attenuated serum levels of cytokines (interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-17A, tumor necrosis factor-α), chemokines (monocyte chemoattractant protein-1, macrophage inflammatory protein-1 beta) and autoantibodies (anti-scleroderma 70 (Scl-70), anti-polymyositis-scleroderma (PM-Scl), anti-centromeres, anti-double stranded DNA (dsDNA). In addition, baicalein treatment can significantly inhibit the activation of TGF-β1 signaling in dermal fibroblasts and bleomycin-induce mice of SSc, evidenced by reducing the expression of TGF-β1 and IL-11, as well as inhibiting both small mother against decapentaplegic homolog 3 (SMAD3) and extracellular signal-related kinase (ERK) activation.

CONCLUSIONS

These findings suggest that baicalein has therapeutic potential against SSc, exerting modulating B-cell abnormalities, anti-inflammatory effects, and antifibrosis.

Pharmacological effects of baicalin in lung diseases

The flavonoids baicalin and baicalein were discovered in the root of Scutellaria baicalensis Georgi and are primarily used in traditional Chinese medicine, herbal supplements and healthcare. Recently, accumulated investigations have demonstrated the therapeutic benefits of baicalin in treating various lung diseases due to its antioxidant, anti-inflammatory, immunomodulatory, antiapoptotic, anticancer, and antiviral effects. In this review, the PubMed database and ClinicalTrials website were searched with the search string "baicalin" and "lung" for articles published between September 1970 and March 2023. We summarized the therapeutic role that baicalin plays in a variety of lung diseases, such as chronic obstructive pulmonary disease, asthma, pulmonary fibrosis, pulmonary hypertension, pulmonary infections, acute lung injury/acute respiratory distress syndrome, and lung cancer. We also discussed the underlying mechanisms of baicalin targeting in these lung diseases.

Mechanistic Effects of Baicalein on Aqueous Humor Drainage and Intraocular Pressure

Elevated intraocular pressure (IOP) is a major risk factor for glaucoma that results from impeded fluid drainage. The increase in outflow resistance is caused by trabecular meshwork (TM) cell dysfunction and excessive extracellular matrix (ECM) deposition. Baicalein (Ba) is a natural flavonoid and has been shown to regulate cell contraction, fluid secretion, and ECM remodeling in various cell types, suggesting the potential significance of regulating outflow resistance and IOP. We demonstrated that Ba significantly lowered the IOP by about 5 mmHg in living mice. Consistent with that, Ba increased the outflow facility by up to 90% in enucleated mouse eyes. The effects of Ba on cell volume regulation and contractility were examined in primary human TM (hTM) cells. We found that Ba (1–100 µM) had no effect on cell volume under iso-osmotic conditions but inhibited the regulatory volume decrease (RVD) by up to 70% under hypotonic challenge. In addition, Ba relaxed hTM cells via reduced myosin light chain (MLC) phosphorylation. Using iTRAQ-based quantitative proteomics, 47 proteins were significantly regulated in hTM cells after a 3-h Ba treatment. Ba significantly increased the expression of cathepsin B by 1.51-fold and downregulated the expression of D-dopachrome decarboxylase and pre-B-cell leukemia transcription factor-interacting protein 1 with a fold-change of 0.58 and 0.40, respectively. We suggest that a Ba-mediated increase in outflow facility is triggered by cell relaxation via MLC phosphorylation along with inhibiting RVD in hTM cells. The Ba-mediated changes in protein expression support the notion of altered ECM homeostasis, potentially contributing to a reduction of outflow resistance and thereby IOP.

MicroRNA-21 promotes epithelial-mesenchymal transition and migration of human bronchial epithelial cells by targeting poly (ADP-ribose) polymerase-1 and activating PI3K/AKT signaling

Epithelial-mesenchymal transition (EMT) is known to be involved in airway remodeling and fibrosis of bronchial asthma. However, the molecular mechanisms leading to EMT have yet to be fully clarified. The current study was designed to reveal the potential mechanism of microRNA-21 (miR-21) and poly (ADP-ribose) polymerase-1 (PARP-1) affecting EMT through the PI3K/AKT signaling pathway. Human bronchial epithelial cells (16HBE cells) were transfected with miR-21 mimics/inhibitors and PARP-1 plasmid/small interfering RNA (siRNA). A dual luciferase reporter assay and biotin-labeled RNA pull-down experiments were conducted to verify the targeting relationship between miR-21 mimics and PARP-1. The migration ability of 16HBE cells was evaluated by Transwell assay. Quantitative real-time polymerase chain reaction and Western blotting experiments were applied to determine the expression of Snail, ZEB1, E-cadherin, N-cadherin, Vimentin, and PARP-1. The effects of the PI3K inhibitor LY294002 on the migration of 16HBE cells and EMT were investigated. Overexpression of miR-21 mimics induced migration and EMT of 16HBE cells, which was significantly inhibited by overexpression of PARP-1. Our findings showed that PARP-1 was a direct target of miR-21, and that miR-21 targeted PARP-1 to promote migration and EMT of 16HBE cells through the PI3K/AKT signaling pathway. Using LY294002 to block PI3K/AKT signaling pathway resulted in a significant reduction in the migration and EMT of 16HBE cells. These results suggest that miR-21 promotes EMT and migration of HBE cells by targeting PARP-1. Additionally, the PI3K/AKT signaling pathway might be involved in this mechanism, which could indicate its usefulness as a therapeutic target for asthma.

Scutellaria baicalensis and its constituents baicalin and baicalein as antidotes or protective agents against chemical toxicities: a comprehensive review

Scutellaria baicalensis (SB), also known as the Chinese skullcap, has a long history of being used in Chinese medicine to treat a variety of conditions ranging from microbial infections to metabolic syndrome and malignancies. Numerous studies have reported that treatment with total SB extract or two main flavonoids found in its root and leaves, baicalin (BA) and baicalein (BE), can prevent or alleviate the detrimental toxic effects of exposure to various chemical compounds. It has been shown that BA and BE are generally behind the protective effects of SB against toxicants. This paper aimed to review the protective and therapeutic effects of SB and its main components BA and BE against chemical compounds that can cause intoxication after acute or chronic exposure and seriously affect different vital organs including the brain, heart, liver, and kidneys. In this review paper, we had a look into a total of 221 in vitro and in vivo studies from 1995 to 2021 from the scientific databases PubMed, Scopus, and Web of Science which reported protective or therapeutic effects of BA, BE, or SB against drugs and chemicals that one might be exposed to on a professional or accidental basis and compounds that are primarily used to simulate disease models. In conclusion, the protective effects of SB and its flavonoids can be mainly attributed to increase in antioxidants enzymes, inhibition of lipid peroxidation, reduction of inflammatory cytokines, and suppression of apoptosis pathway.

Therapeutic and prophylactic effect of flavonoids in post-COVID-19 therapy

The high incidence of post-covid symptoms in humans confirms the need for effective treatment. Due to long-term complications across several disciplines, special treatment programs emerge for affected patients, emphasizing multidisciplinary care. For these reasons, we decided to look at current knowledge about possible long-term complications of COVID-19 disease and then present the effect of flavonoids, which could help alleviate or eliminate complications in humans after overcoming the COVID-19 infection. Based on articles published from 2003 to 2021, we summarize the flavonoids-based molecular mechanisms associated with the post-COVID-19 syndrome and simultaneously provide a complex view regarding their prophylactic and therapeutic potential. Review clearly sorts out the outcome of post-COVID-19 syndrome according particular body systems. The conclusion is that flavonoids play an important role in prevention of many diseases. We suggest that flavonoids as critical nutritional supplements, are suitable for the alleviation and shortening of the period associated with the post-COVID-19 syndrome. The most promising flavonoid with noteworthy therapeutic and prophylactic effect appears to be quercetin.

Wenfei Buqi Tongluo Formula Against Bleomycin-Induced Pulmonary Fibrosis by Inhibiting TGF-β/Smad3 Pathway

Pulmonary fibrosis (PF) is the end stage of various chronic and progressive interstitial lung diseases. TGF-β, a profibrotic cytokine, can promote epithelial–mesenchymal transition (EMT), extracellular matrix (ECM) accumulation, and fibroblast proliferation, which contribute to progressive lung remodeling in PF. The Wenfei Buqi Tongluo (WBT) formula has been certified to be effective in the prevention and treatment of PF in clinical practice and has inhibitory effects on EMT, inflammation, and profibrotic factors. However, the pharmacological mechanisms of WBT against PF need to be further explored. In this study, we first analyzed the chemical components of the WBT formula using the UHPLC/Q-TOF-MS analysis. The potential targets of the identified compounds from WBT were predicted by the network pharmacology, which was confirmed by in vivo and in vitro study. After screening by the PubChem database, we first identified the 36 compounds of WBT and predicted the TGF-β signaling pathway, with ECM degradation as potential mechanism of WBT against PF by the network pharmacology. Furthermore, WBT treatment inhibited the levels of TGF-β and Smad3 phosphorylation and subsequently alleviated EMT and ECM accumulation in the bleomycin-induced mouse model and TGF-β1–induced cell model. These findings indicate that WBT can block the progressive process of PF by inhibiting EMT and promoting ECM degradation via the TGF-β/Smad3 pathway. This study may provide new insights into the molecular mechanism of WBT for the prevention and treatment of PF in the clinical application.

An overview of pharmacological activities of baicalin and its aglycone baicalein: New insights into molecular mechanisms and signaling pathways

The flavonoids, baicalin, and its aglycone baicalein possess multi-fold therapeutic properties and are mainly found in the roots of Oroxylum indicum (L.) Kurz and Scutellaria baicalensis Georgi. These flavonoids have been reported to possess various pharmacological properties, including antibacterial, antiviral, anticancer, anticonvulsant, anti-oxidant, hepatoprotective, and neuroprotective effects. The pharmacological properties of baicalin and baicalein are due to their abilities to scavenge reactive oxygen species (ROS) and interaction with various signaling molecules associated with apoptosis, inflammation, autophagy, cell cycle, mitochondrial dynamics, and cytoprotection. In this review, we summarized the molecular mechanisms underlying the chemopreventive and chemotherapeutic applications of baicalin and baicalein in the treatment of cancer and inflammatory diseases. In addition, the preventive effects of baicalin and baicalein on mitochondrial dynamics and functions were highlighted with a particular emphasis on their anti-oxidative and cytoprotective properties. The current review highlights could be useful for future prospective studies to further improve the pharmacological applications of baicalein and baicalin. These studies should define the threshold for optimal drug exposure, dose optimization and focus on therapeutic drug monitoring, objective disease markers, and baicalin/baicalein drug levels.

Mitomycin induces alveolar epithelial cell senescence by down-regulating GSK3β signaling

Mitomycin treatment induces pulmonary toxicity, and alveolar epithelial cell senescence is crucial in the pathogenesis of the latter. However, the mechanism by which mitomycin induces alveolar epithelial cell senescence has yet to be elucidated. In this work, different doses (37.5-300 nM) of mitomycin induced the senescence of human alveolar type II-like epithelial cells and enhanced the phosphorylation of GSK3β (S9). The GSK3β (S9A) mutant reversed the senescence of mitomycin-treated alveolar epithelial cells. Pharmacological inhibition and gene deletion of Akt1, a kinase that regulates the phosphorylation of GSK3β (S9), suppressed mitomycin-induced alveolar epithelial cell senescence. The knockdown of p53, a downstream effector of GSK3β and an important regulator of cell senescence, repressed mitomycin-induced alveolar epithelial cell senescence. Treatment with baicalein weakened the phosphorylation of GSK3β (S9) and alleviated the senescence of alveolar epithelial cells brought about by mitomycin treatment. GSK3β (S9) phosphorylation appears to be the first signal involved in the mitomycin-induced senescence of alveolar epithelial cells and may present a potential target for attenuating mitomycin-induced pulmonary toxicity.

Downregulation of microRNA-21 contributes to decreased collagen expression in venous malformations via transforming growth factor-β/Smad3/microRNA-21 signaling feedback loop

OBJECTIVE

Venous malformations (VMs) are the most frequent vascular malformations and are characterized by dilated and tortuous veins with a dysregulated vascular extracellular matrix. The purpose of the present study was to investigate the potential involvement of microRNA-21 (miR-21), a multifunctional microRNA tightly associated with extracellular matrix regulation, in the pathogenesis of VMs.

METHODS

The expression of miR-21, collagen I, III, and IV, transforming growth factor-β (TGF-β), and Smad3 (mothers against decapentaplegic homolog 3) was evaluated in VMs and normal skin tissue using in situ hybridization, immunohistochemistry, Masson trichrome staining, and real-time polymerase chain reaction. Human umbilical vein endothelial cells (HUVECs) were used to explore the underlying mechanisms.

RESULTS

miR-21 expression was markedly decreased in the VM specimens compared with normal skin, in parallel with downregulation of collagen I, III, and IV and the TGF-β/Smad3 pathway in VMs. Moreover, our data demonstrated that miR-21 positively regulated the expression of collagens in HUVECs and showed a positive association with the TGF-β/Smad3 pathway in the VM tissues. In addition, miR-21 was found to mediate TGF-β-induced upregulation of collagens in HUVECs. Our data have indicated that miR-21 and the TGF-β/Smad3 pathway could form a positive feedback loop to synergistically regulate endothelial collagen synthesis. In addition, TGF-β/Smad3/miR-21 feedback loop signaling was upregulated in bleomycin-treated HUVECs and VM specimens, which was accompanied by increased collagen deposition.

CONCLUSIONS

To the best of our knowledge, the present study has, for the first time, revealed downregulation of miR-21 in VMs, which might contribute to decreased collagen expression via the TGF-β/Smad3/miR-21 signaling feedback loop. These findings provide new information on the pathogenesis of VMs and might facilitate the development of new therapies for VMs.

Mechanism of Fei-Xian Formula in the Treatment of Pulmonary Fibrosis on the Basis of Network Pharmacology Analysis Combined with Molecular Docking Validation

Objective

This study aimed to clarify the mechanism of Fei-Xian formula (FXF) in the treatment of pulmonary fibrosis based on network pharmacology analysis combined with molecular docking validation.

Methods

Firstly, ingredients in FXF with pharmacological activities, together with specific targets, were identified based on the BATMA-TCM and TCMSP databases. Then, targets associated with pulmonary fibrosis, which included pathogenic targets as well as those known therapeutic targets, were screened against the CTD, TTD, GeneCards, and DisGeNet databases. Later, Cytoscape was employed to construct a candidate component-target network of FXF for treating pulmonary fibrosis. In addition, for nodes within the as-constructed network, topological parameters were calculated using CytoHubba plug-in, and the degree value (twice as high as the median degree value for all the nodes) was adopted to select core components as well as core targets of FXF for treating pulmonary fibrosis, which were subsequently utilized for constructing the core network. Furthermore, molecular docking study was carried out on those core active ingredients together with the core targets using AutoDock Vina for verifying results of network pharmacology analysis. At last, OmicShare was employed for enrichment analysis of the core targets.

Results

Altogether 12 active ingredients along with 13 core targets were identified from our constructed core component-target network of FXF for the treatment of pulmonary fibrosis. As revealed by enrichment analysis, the 13 core targets mostly concentrated in regulating biological functions, like response to external stimulus (from oxidative stress, radiation, UV, chemical substances, and virus infection), apoptosis, cell cycle, aging, immune process, and protein metabolism. In addition, several pathways, like IL-17, AGE-RAGE, TNF, HIF-1, PI3K-AKT, NOD-like receptor, T/B cell receptor, and virus infection-related pathways, exerted vital parts in FXF in the treatment of pulmonary fibrosis.

Conclusions

FXF can treat pulmonary fibrosis through a “multicomponent, multitarget, and multipathway” mean. Findings in this work lay foundation for further exploration of the FXF mechanism in the treatment of pulmonary fibrosis.

MYH9 Inhibition Suppresses TGF-β1-Stimulated Lung Fibroblast-to-Myofibroblast Differentiation

Previous cDNA microarray results showed that MYH9 gene expression levels are increased in TGF-β1-stimulated lung fibroblast. Recently, our proteomic results revealed that the expression levels of MYH9 protein are notably upregulated in lung tissues of bleomycin-treated rats. However, whether MYH9 plays a critical role in the differentiation of fibroblast remains unclear. Herein, we demonstrated that TGF-β1 increased MYH9 expression, and siRNA-mediated knockdown of MYH9 and pharmacological inhibition of MYH9 ATPase activity remarkably repressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation. TGF-β1-stimulated MYH9 induction might be via ALK5/Smad2/3 pathway but not through noncanonical pathways, including p38 mitogen-activated kinase, and Akt pathways in lung fibroblasts. Our results showed that MYH9 inhibition suppressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation, which provides valuable information for illuminating the pathological mechanisms of lung fibroblast differentiation, and gives clues for finding new potential target for pulmonary fibrosis treatment.

Inhibiting TGF-[Formula: see text] 1-Mediated Cellular Processes as an Effective Strategy for the Treatment of Pulmonary Fibrosis with Chinese Herbal Medicines

Pulmonary fibrosis (PF) is a chronic and irreversible interstitial lung disease that even threatens the lives of some patients infected with COVID-19. PF is a multicellular pathological process, including the initial injuries of epithelial cells, recruitment of inflammatory cells, epithelial-mesenchymal transition, activation and differentiation of fibroblasts, etc. TGF-[Formula: see text]1 acts as a key effect factor that participates in these cellular processes of PF. Recently, much attention was paid to inhibiting TGF-[Formula: see text]1 mediated cell processes in the treatment of PF with Chinese herbal medicines (CHM), an important part of traditional Chinese medicine. Here, this review first summarized the effects of TGF-[Formula: see text]1 in different cellular processes of PF. Then, this review summarized the recent research on CHM (compounds, multi-components, single medicines and prescriptions) to directly and/or indirectly inhibit TGF-[Formula: see text]1 signaling (TLRs, PPARs, micrRNA, etc.) in PF. Most of the research focused on CHM natural compounds, including but not limited to alkaloids, flavonoids, phenols and terpenes. After review, the research perspectives of CHM on TGF-[Formula: see text]1 inhibition in PF were further discussed. This review hopes that revealing the inhibiting effects of CHM on TGF-[Formula: see text]1-mediated cellular processes of PF can promote CHM to be better understood and utilized, thus transforming the therapeutic activities of CHM into practice.

More than a Genetic Code: Epigenetics of Lung Fibrosis

At the end of the last century, genetic studies reported that genetic information is not transmitted solely by DNA, but is also transmitted by other mechanisms, named as epigenetics. The well-described epigenetic mechanisms include DNA methylation, biochemical modifications of histones, and microRNAs. The role of altered epigenetics in the biology of various fibrotic diseases is well-established, and recent advances demonstrate its importance in the pathogenesis of pulmonary fibrosis-predominantly referring to idiopathic pulmonary fibrosis, the most lethal of the interstitial lung diseases. The deficiency in effective medications suggests an urgent need to better understand the underlying pathobiology. This review summarizes the current knowledge concerning epigenetic changes in pulmonary fibrosis and associations of these changes with several cellular pathways of known significance in its pathogenesis. It also designates the most promising substances for further research that may bring us closer to new therapeutic options.

Baicalein alleviated TGF β1-induced type I collagen production in lung fibroblasts via downregulation of connective tissue growth factor

Although we have reported that baicalein ameliorated bleomycin-induced pulmonary fibrosis in rats and inhibited fibroblast-to-myofibroblast differentiation, the mechanisms of the capability of baicalein to suppress the production of type I collagen in fibroblasts remains unclear. Here, we showed that baicalein suppressed transforming growth factor β1 (TGF β1)-stimulated the production of type I collagen in lung fibroblast MRC-5 cells. By applying SILAC-based proteomic technology, 158 proteins were identified as baicalein-modulated proteins in TGF β1-stimulated the accumulation of type I collagen in MRC-5 cells. Our proteomic and biochemical analysis demonstrated that baicalein decreased the expression levels of connective tissue growth factor (CTGF) in TGF β1-stimulated MRC-5 cells. In addition, CTGF overexpression elevated the levels of type I collagen in baicalein-treated fibroblasts. Moreover, our results demonstrated that baicalein-downregulated CTGF expression might be related with the decrease of Smad2 phosphorylation, but not SP1. This work not only linked CTGF to TGF β1-stimulated the production of type I collagen in its attribution to the effects of baicalein, but also might provide valuable information for enhancing the knowledge of the pharmacological inhibition of collagen production, which might represent a promising strategy for the treatment of pulmonary fibrosis.

Gallic acid and ferulic acid protect the liver from thioacetamide-induced fibrosis in rats via differential expression of miR-21, miR-30 and miR-200 and impact on TGF-β1/Smad3 signaling

This study evaluates the possible protective effects of gallic acid (GaA) and ferulic acid (FeA) against an experimentally induced liver fibrosis by thioacetamide (TAA) in rats. Animals were divided into: Control group, GaA group (20 mg/kg/day, p.o), FeA (20 mg/kg/day, p.o), TAA group (receiving 250 mg/kg twice/week, I.P), TAA + GaA group, TAA + FeA group (received the same previous doses) and TAA+silymarin group (received silymarin at 100 mg/kg/day+TAA as mentioned above). After 6 consecutive weeks, animals were sacrificed and the assessment of liver functions, oxidative stress biomarkers and histopathological examination of the liver tissues were performed. In addition, the effect on TGF-β1/Smad3 signaling and the expression of miR-21, miR-30 and miR-200 were evaluated. The results showed that administration of GaA or FeA with TAA induced a significant reduction in serum ALT, AST and ALP activities and protected the integrity of liver tissues. Furthermore, they increased the activities of the hepatic antioxidant enzymes; superoxide dismutase and catalase while decreased malondialdehyde content to a normal level. The hepatic expression of TGF-β1, phosphorylated and total Smad3 proteins were significantly decreased. In addition, miR-21 expression was downregulated while miR-30 and miR-200 expressions were upregulated by administration of gallic acid or ferulic acid. In conclusion, gallic and ferulic acids exhibit hepatoprotective and antioxidant effects against TAA-induced liver fibrosis in rats. These effects are mediated through inhibition of TGF-β1/Smad3 signaling and differentially regulating the hepatic expression level of miR-21, miR-30 and miR-200.

miR-21-KO Alleviates Alveolar Structural Remodeling and Inflammatory Signaling in Acute Lung Injury

Acute lung injury (ALI) is characterized by enhanced permeability of the air–blood barrier, pulmonary edema, and hypoxemia. MicroRNA-21 (miR-21) was shown to be involved in pulmonary remodeling and the pathology of ALI, and we hypothesized that miR-21 knock-out (KO) reduces injury and remodeling in ALI. ALI was induced in miR-21 KO and C57BL/6N (wildtype, WT) mice by an intranasal administration of 75 µg lipopolysaccharide (LPS) in saline (n = 10 per group). The control mice received saline alone (n = 7 per group). After 24 h, lung function was measured. The lungs were then excised for proteomics, cytokine, and stereological analysis to address inflammatory signaling and structural damage. LPS exposure induced ALI in both strains, however, only WT mice showed increased tissue resistance and septal thickening upon LPS treatment. Septal alterations due to LPS exposure in WT mice consisted of an increase in extracellular matrix (ECM), including collagen fibrils, elastic fibers, and amorphous ECM. Proteomics analysis revealed that the inflammatory response was dampened in miR-21 KO mice with reduced platelet and neutrophil activation compared with WT mice. The WT mice showed more functional and structural changes and inflammatory signaling in ALI than miR-21 KO mice, confirming the hypothesis that miR-21 KO reduces the development of pathological changes in ALI.

Inhibitory effects of formononetin on the monocrotaline‑induced pulmonary arterial hypertension in rats

Pulmonary arterial hypertension (PAH) is a fatal syndrome resulting from enhanced pulmonary arterial pressure and pulmonary vessel resistance. Perivascular inflammation and extracellular matrix deposition are considered to be the crucial pathophysiologic bases of PAH. Formononetin (FMN), a natural phytoestrogen isolated from red clover (Trifolium pratense), has a variety of proapoptotic, anti-inflammatory and anti-tumor activities. However, the therapeutic effectiveness of FMN for PAH remains unclear. In the present study, 60 mg/kg monocrotaline (MCT) was first used to induce PAH in rats, and then all rats were treated with different concentrations of FMN (10, 30 and 60 mg/kg/day). At the end of this study, the hemodynamics and pulmonary vascular morphology of rats were evaluated. Specifically, matrix metalloproteinase (MMP)2, transforming growth factor β1 (TGFβ1) and MMP9 were measured using western blot and immunohistochemical staining. Collagen type I, collagen type III, fibronectin, monocyte chemotactic protein-1, tumor necrosis factor-α, interleukin-1β, ERK and NF-κB were quantified using western blotting. The results demonstrated that FMN significantly alleviated the changes of hemodynamics and pulmonary vascular morphology, and decreased the MCT-induced upregulations of TGFβ1, MMP2 and MMP9 expression levels. Meanwhile, the expression levels of collagen type I, collagen type III and fibronectin in rat lungs decreased after FMN treatment. Furthermore, the phosphorylated ERK and NF-κB also decreased after FMN treatment. Taken together, the present study indicated that FMN serves a therapeutic role in the MCT-induced PAH in rats via suppressing pulmonary vascular remodeling, which may be partially related to ERK and NF-κB signals.

Hesperidin ameliorates bleomycin-induced experimental pulmonary fibrosis via inhibition of TGF-beta1/Smad3/AMPK and IkappaBalpha/NF-kappaB pathways

Bleomycin (BLM) is a chemotherapeutic agent which is associated with Idiopathic pulmonary fibrosis (IPF) due to its chronic administration. Hesperidin, a bioflavonoid has been reported to possess antioxidant, anti-inflammatory, wound healing, and antiapoptotic potential. To evaluate the therapeutic potential of hesperidin against BLM-induced pulmonary fibrosis and decipher its possible mechanism of action. Intraperitoneal administration of BLM (6 IU/kg) caused induction of IPF in Sprague-Dawley rats. Rats were treated with hesperidin (25, 50, and 100 mg/kg, p.o.) for 28 days, followed by estimation of various parameters in bronchoalveolar lavage fluid (BALF) and lung. Hesperidin (50 and 100 mg/kg) administration significantly ameliorated (p < 0.05) alterations induced by BLM in lung index, percent oxygen saturation, serum ALP and LDH levels, BALF differential cell count, and lung function test. Elevated levels of oxido-nitrosative stress, hydroxyproline, and myeloperoxidase levels in BALF and lung were significantly decreased by hesperidin on day 14. Hesperidin significantly inhibited BLM-induced down-regulated lung Nrf2 and HO-1 as well as up-regulated TNF-α, IL-1β, IL-6, collagen-1, TGF-β, and Smad-3 mRNA expressions. Western blot analysis showed that alteration in lung NF-κB, IκBα, AMPK, and PP2C-α protein expressions were ameliorated by hesperidin on day 28. Furthermore, BLM induced histological and ultrastructural aberrations in the lung which were attenuated by hesperidin treatment. Hesperidin alleviates BLM-induced IPF via inhibition of TGF-β1/Smad3/AMPK and IκBα/NF-κB pathways which in turn ameliorate the modulation of oxido-inflammatory markers (Nrf2 and HO-1) and pro-inflammatory markers (TNF-α, IL-1β, and IL-6) to reduce collagen deposition during pulmonary fibrosis. See also Figure 1(Fig. 1).

More than just an enzyme: Dipeptidyl peptidase-4 (DPP-4) and its association with diabetic kidney remodelling

PURPOSE OF THE REVIEW

This review article discusses recent advances in the mechanism of dipeptidyl peptidase-4 (DPP-4) actions in renal diseases, especially diabetic kidney fibrosis, and summarizes anti-fibrotic functions of various DPP-4 inhibitors in diabetic nephropathy (DN).

RECENT FINDINGS

DN is a common complication of diabetes and is a leading cause of the end-stage renal disease (ESRD). DPP-4 is a member of serine proteases, and more than 30 substrates have been identified that act via several biochemical messengers in a variety of tissues including kidney. Intriguingly, DPP-4 actions on the diabetic kidney is a complex mechanism, and a variety of pathways are involved including increasing GLP-1/SDF-1, disrupting AGE-RAGE pathways, and integrin-β- and TGF-β-Smad-mediated signalling pathways that finally lead to endothelial to mesenchymal transition. Interestingly, an array of DPP-4 inhibitors is well recognized as oral drugs to treat type 2 diabetic (T2D) patients, which promote better glycemic control. Furthermore, recent experimental and preclinical data reveal that DPP-4 inhibitors may also exhibit protective effects in renal disease progression including anti-fibrotic effects in the diabetic kidney by attenuating above signalling cascade(s), either singly or as a combinatorial effect. In this review, we discussed the anti-fibrotic effects of DPP-4 inhibitors based on recent reports along with the possible mechanism of actions and future perspectives to underscore the beneficial effects of DPP-4 inhibitors in DN.

SUMMARY

With recent experimental, preclinical, and clinical evidence, we summarized DPP-4 activities and its mechanism of actions in diabetic kidney diseases. A knowledge gap of DPP-4 inhibition in controlling renal fibrosis in DN has also been postulated in this review for future research perspectives.

Baicalein retards proliferation and collagen deposition by activating p38MAPK-JNK via microRNA-29

Immoderate proliferation and deposition of collagen generally result in hypertrophic scars and even keloids. microRNA-29 (miR-29) has been proved as a crucial regulator in these pathological processes. Although mounting evidence have proved baicalein (BAI) impairs scar formation, it is still incompletely understood whether miR-29 participated in the underlying mechanism. In the present study, NIH-3T3 cells were stimulated with BAI, and then cell viability was analyzed by cell counting kit-8 (CCK-8) and Western blot. We further analyzed total soluble collagen, collagen 1, and alpha-smooth muscle actin (α-SMA) in NIH-3T3 cells, which were exposed to transforming growth factor beta 1 (TGF-β1)/BAI, using a Sircol assay kit, quantitative reverse transcription-PCR (qRT-PCR) and Western blot, respectively. Besides, the miR-29 inhibitor was transduced and its transfection efficiency was verified by qRT-PCR. Finally, the phosphorylated p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK) were examined by Western blot. BAI effectively retarded NIH-3T3 proliferation in a dose-dependent manner. Besides, TGF-β1-induced deposition of total soluble collagen and synthesis of collagen 1 and α-SMA were repressed by BAI at mRNA and protein levels. However, miR-29 inhibitor reversed the effects of BAI. Remarkably, BAI promoted phosphorylated expression of p38MAPK and JNK while miR-29 inhibitor reversed its effects on the phosphorylated expression of p38MAPK and JNK. BAI effectively weakened the cell viability and repressed TGF-β1-induced total soluble collagen as well as collagen 1 and α-SMA by upregulating miR-29. Mechanically, BAI activates the p38MAPK/JNK pathway by promoting miR-29.

Combined Biomarkers Composed of Environment and Genetic Factors in Stroke

It was widely accepted that stroke onset was the result of interactions between environment and genetic factors. However, the combined biomarkers covering environment and genetic factors and their interplay information in stroke were still lacking. In this study, we proposed a framework to identify the targeting or indicating role each factor played in the combined stroke biomarkers. A combined set of 36 biomarkers were identified based on evaluation and importance scores. Validations on three independent microarray data sets justified that the obtained markers were pervasively effective in discriminating stroke patients of different stages from healthy people on genetic levels. 8 and 3 genetic factors were identified as biomarkers in the acute and recovery phases of stroke, respectively. For example, the expression changing of SERPINH1 only appeared in the acute phase of stroke showing its targeting role in the combined biomarker. Compared with this, 11 genetic factors such as MMP9 were found to be differentially expressed in both acute and recovery phases of stroke showing their indicating roles in stroke. Functional analyses further revealed that the biomarkers could be grouped into 4 closely related processes of stroke including prevention, occurrence, processing, and recovery, respectively. These results indicated that the adoption of interactions between environment and genetic factors would be helpful in selecting robust and biologically relevant biomarkers, which cast a new insight for stroke biomarker identification.

Baicalein attenuates monocrotaline-induced pulmonary arterial hypertension by inhibiting endothelial-to-mesenchymal transition

AIMS

Endothelial-to-mesenchymal transition (EndoMT) was shown to lead to endothelial cell (EC) dysfunction in pulmonary arterial hypertension (PAH). Baicalein was reported to inhibit epithelial-to-mesenchymal transition (EMT), a biological process that has many regulatory pathways in common with EndoMT. Whether it can attenuate PAH by inhibiting EndoMT remains obscure.

MAIN METHODS

PAH was induced by a single subcutaneous injection of MCT (60 mg/kg) in male Sprague Dawley rats. Two weeks after MCT administration, the rats in the treatment groups received baicalein orally (50 or 100 mg/kg/day) for an additional 2 weeks. Hemodynamic changes and right ventricular hypertrophy (RVH) were evaluated on day 28. Cardiopulmonary interstitial fibrosis was detected using Masson's trichrome, Picrosirius-red, and immunohistochemical staining. The reactivity of pulmonary arteries (PAs) was examined ex vivo. The protein expresson of EndoMT molecules, bone morphogenetic protein receptor 2 (BMPR2), and nuclear factor-κB (NF-κB) was examined to explore the mechanism of protective action of baicalein.

KEY FINDINGS

Baicalein (50 and 100 mg/kg) significantly alleviated MCT-induced PAH and cardiopulmonary interstitial fibrosis. Furthermore, baicalein treatment enhanced PA responsiveness to acetylcholine (ACh) in PAH rats. The upregulation of EndoMT molecules (N-cadherin, vimentin, Snail, and Slug) strongly suggest that EndoMT participates in MCT-induced PAH, which was reversed by baicalein (50 and 100 mg/kg) treatment. Moreover, baicalein partially reversed MCT-induced reductions in BMPR2 and NF-κB activation in the PAs.

SIGNIFICANCE

Baicalein attenuated MCT-induced PAH in rats by inhibiting EndoMT partially via the NF-κB-BMPR2 pathway. Thus, baicalein might be considered as a promising treatment option for PAH.

Resveratrol inhibits pulmonary fibrosis by regulating miR-21 through MAPK/AP-1 pathways

OBJECTIVE

To explore the molecular mechanism of Res in regulation of pulmonary fibrosis (PF).

METHODS

Rats were injected with bleomycin (BLM) to establish a PF model and treated with resveratrol (Res) and/or miR-21 agomir. After 14 days, lung tissues were collected for Hematoxylin-eosin and Masson's staining, and real-time quantitative polymerase chain reaction and Western blot were performed to detect fibrosis-related protein expression and the activation of the TGF-β1/Smad pathway. In vitro, MRC-5 cells were pretreated with TGF-β1, Res, and/or miR-21 agomir. After 48 h, total soluble collagen was detected with a Sircol Soluble Collagen Assay. Subsequently, a miR-21 mimic was transfected into MRC-5 cells, and a luciferase reporter assay was employed to verify whether miR-21 targeted Smad7.

RESULTS

Res reversed the increased levels of miR-21 induced by BLM and alleviated serious PF symptoms, but agomiR-21 treatment effectively impaired the above manifestations. In vivo, miR-21 inhibited the decreases of TGF-β1 and p-Smad2/3 that were induced by Res. In vitro, miR-21 significantly disrupted the positive effect of Res on TGF-β-induced collagen deposition, as well as the levels of Fn, α-SMA, p-Smad2, and Smad7. In addition, Smad7 was found to be a direct target of miR-21-5p. TGF-β stimulation led to an enormous increase in p-c-Jun, c-Jun, and c-Fos, which were significantly reduced by Res. Finally, miR-21 sharply reduced the increased phosphorylation levels of ERK, JNK and p38 that were induced by Res.

CONCLUSION

Res inhibits BLM-induced PF by regulating miR-21 through MAPK/AP-1 pathways.

Mutual regulation between miR-21 and the TGFβ/Smad signaling pathway in human bronchial fibroblasts promotes airway remodeling

OBJECTIVE

Airway remodeling is an important pathological feature of asthma. Excessive deposition of extracellular matrix (e.g., collagen) secreted from fibroblasts is a major factor contributing to airway remodeling. Currently, the mechanism by which collagen continues to be oversynthesized in the airway remains unclear. In this study, we investigated the role of the microRNA-21 (miR-21) and TGFβ/Smad signaling pathway in human bronchial fibroblasts (HBFs), and explored the regulatory mechanism of airway remodeling.

METHODS

HBFs were cultured in vitro and treated with the transforming growth factor β (TGFβ), receptor inhibitor (SB431542), and TGFβ1. miR-21 and Smad7 overexpressing lentiviruses, as well as an miR-21 interfering lentivirus were constructed and transfected into HBFs. Western blotting was used to determine the expression of airway remodeling-related proteins and proteins in the TGFβ/Smad signaling pathway. miR-21 expression was measured by quantitative real-time PCR.

RESULTS

The high expression of miR-21 induced by TGFβ1 was reduced following the treatment with the SB431542 in HBFs. Smad7 overexpression inhibited the elevated expression of the COL I protein induced by miR-21 overexpression in HBFs. Inhibiting miR-21 expression upregulated the level of Smad7 protein, thus reducing the expression of airway remodeling-related proteins induced by TGFβ1 stimulation in HBFs.

CONCLUSIONS

TGFβ1 can induce miR-21 expression in HBFs through the TGFβ/Smad signaling pathway to promote airway remodeling. miR-21 downregulates Smad7, activates the TGFβ/Smad signaling pathway, and promotes airway remodeling. Mutual regulation between miR-21 and the TGFβ/Smad signaling pathway in HBFs promotes airway remodeling.

Liposome-Encapsulated Baicalein Suppressed Lipogenesis and Extracellular Matrix Formation in Hs68 Human Dermal Fibroblasts

The dermis of human skin contains large numbers of fibroblasts that are responsible for the production of the extracellular matrix (ECM) that supporting skin integrity, elasticity and wound healing. Previously, an in vivo study demonstrated that dermal fibroblasts siting in the lower dermis are capable to convert into skin adipose layer and hence fibroblast lipogenesis may vary the structure and elasticity of dermis. In the present study, Hs68 human dermal fibroblasts were utilized as an in vitro model to study the lipogenesis via using adipogenic differentiation medium (ADM). Baicalein, isolated from Scutellaria baicalensis, is one of the flavonoids to inhibit adipocyte differentiation due to high antioxidant activity in vitro. In order to develop a suitable formulation for baicalein (a poorly water-soluble drug), soybean phosphatidylcholine (SPC) was used to prepare baicalein-loaded liposomes to enhance drug bioavailability. Our results demonstrated that liposome-encapsulated baicalein protected cell viability and increased cellular uptake efficiency of Hs68 fibroblasts. Lipid accumulation, triglyceride synthesis and gene expressions of lipogenesis enzymes (FABP4 and LPL) were significantly increased in ADM-stimulated Hs68 fibroblasts but subsequently suppressed by liposome-encapsulated baicalein. In addition, ADM-induced TNF-α expression and related inflammatory factors was down-regulated by liposome-encapsulated baicalein. Through ADM-induced lipogenesis, the protein expression of elastin, type I and type III collagens increased remarkably, whereas liposome-encapsulated baicalein can down-regulate ADM-induced ECM protein synthesis. Taken together, we found that liposome-encapsulated baicalein can inhibit ADM-induced lipid accumulation and ECM formation in Hs68 fibroblasts through the suppression of lipogenesis enzymes and inflammatory responses. Liposome-encapsulated baicalein may have the potential to improve wound healing and restore skin structure after skin injury.

F2-isoprostanes can mediate bleomycin-induced lung fibrosis

F₂-isoprostanes (F₂-IsoPs) have been considered markers of oxidative stress in various pulmonary diseases, but little is known about their possible role in pulmonary fibrosis. In this study, we have investigated the potential key role of F₂-IsoPs as markers and mediators of bleomycin (BLM)-induced pulmonary fibrosis in rats. During the in vivo study, plasma F₂-IsoPs showed a peak at 7 days and remained elevated for the entire experimental period. Lung F₂-IsoP content nearly tripled 7 days following the intratracheal instillation of BLM, and by 28 days, the value increased about fivefold compared to the controls. Collagen deposition correlated with F₂-IsoP content in the lung. Furthermore, from day 21 onwards, lung sections from BLM-treated animals showed α-smooth muscle actin (α-SMA) positive cells, which were mostly evident at 28 days. In vitro studies performed in rat lung fibroblasts (RLF) demonstrated that either BLM or F₂-IsoPs stimulated both cell proliferation and collagen synthesis. Moreover, RLF treated with F₂-IsoPs showed a significant increase of α-SMA expression compared to control, indicating that F₂-IsoPs can readily activate fibroblasts to myofibroblasts. Our data demonstrated that F₂-IsoPs can be mediators of key events for the onset and development of lung fibrosis, such as cell proliferation, collagen synthesis and fibroblast activation. Immunocytochemistry analysis, inhibition and binding studies demonstrated the presence of the thromboxane A₂ receptor (TP receptor) on lung fibroblasts and suggested that the observed effects may be elicited through the binding to this receptor. Our data added a new perspective on the role of F₂-IsoPs in lung fibrosis by providing evidence of a profibrotic role for these mediators in the pathogenesis of pulmonary fibrosis.

Role of MicroRNAs in TGF-β Signaling Pathway-Mediated Pulmonary Fibrosis

Pulmonary fibrosis is the most common form of interstitial lung disease. The transforming growth factor-β (TGF-β) signaling pathway is extensively involved in the development of pulmonary fibrosis by inducing cell differentiation, migration, invasion, or hyperplastic changes. Accumulating evidence indicates that microRNAs (miRNAs) are dysregulated during the initiation of pulmonary fibrosis. miRNAs are small noncoding RNAs functioning as negative regulators of gene expression at the post-transcriptional level. A number of miRNAs have been reported to regulate the TGF-β signaling pathway and consequently affect the process of pulmonary fibrosis. A better understanding of the pro-fibrotic role of the TGF-β signaling pathway and relevant miRNA regulation will shed light on biomedical research of pulmonary fibrosis. This review summarizes the current knowledge of miRNAs regulating the TGF-β signaling pathway with relevance to pulmonary fibrosis.

Drugs and Targets in Fibrosis

Fibrosis contributes to the development of many diseases and many target molecules are involved in fibrosis. Currently, the majority of fibrosis treatment strategies are limited to specific diseases or organs. However, accumulating evidence demonstrates great similarities among fibroproliferative diseases, and more and more drugs are proved to be effective anti-fibrotic therapies across different diseases and organs. Here we comprehensively review the current knowledge on the pathological mechanisms of fibrosis, and divide factors mediating fibrosis progression into extracellular and intracellular groups. Furthermore, we systematically summarize both single and multiple component drugs that target fibrosis. Future directions of fibrosis drug discovery are also proposed.