Ferulic acid suppresses activation of hepatic stellate cells through ERK1/2 and Smad signaling pathways in vitro

Molecular mechanism and research progress on pharmacology of ferulic acid in liver diseases

Ferulic acid (FA) is a natural polyphenol, a derivative of cinnamic acid, widely found in Angelica, Chuanxiong and other fruits, vegetables and traditional Chinese medicine. FA contains methoxy, 4-hydroxy and carboxylic acid functional groups that bind covalently to neighbouring adjacent unsaturated Cationic C and play a key role in many diseases related to oxidative stress. Numerous studies have shown that ferulic acid protects liver cells and inhibits liver injury, liver fibrosis, hepatotoxicity and hepatocyte apoptosis caused by various factors. FA has protective effects on liver injury induced by acetaminophen, methotrexate, antituberculosis drugs, diosbulbin B and tripterygium wilfordii, mainly through the signal pathways related to TLR4/NF-κB and Keap1/Nrf2. FA also has protective effects on carbon tetrachloride, concanavalin A and septic liver injury. FA pretreatment can protect hepatocytes from radiation damage, protects the liver from damage caused by fluoride, cadmium and aflatoxin b1. At the same time, FA can inhibit liver fibrosis, inhibit liver steatosis and reduce lipid toxicity, improve insulin resistance in the liver and exert the effect of anti-liver cancer. In addition, signalling pathways such as Akt/FoxO1, AMPK, PPAR γ, Smad2/3 and Caspase-3 have been shown to be vital molecular targets for FA involvement in improving various liver diseases. Recent advances in the pharmacological effects of ferulic acid and its derivatives on liver diseases were reviewed. The results will provide guidance for the clinical application of ferulic acid and its derivatives in the treatment of liver diseases.

Ferulic Acid: A Review of Pharmacology, Toxicology, and Therapeutic Effects on Pulmonary Diseases

Ferulic acid (FA), a prevalent dietary phytochemical, has many pharmacological effects, including anti-oxidation and anti-inflammation effects, and has been widely used in the pharmaceutical, food, and cosmetics industries. Many studies have shown that FA can significantly downregulate the expression of reactive oxygen species and activate nuclear factor erythroid-2-related factor-2/heme oxygenase-1 signaling, exerting anti-oxidative effects. The anti-inflammatory effect of FA is mainly related to the p38 mitogen-activated protein kinase and nuclear factor-kappaB signaling pathways. FA has demonstrated potential clinical applications in the treatment of pulmonary diseases. The transforming growth factor-β1/small mothers against decapentaplegic 3 signaling pathway can be blocked by FA, thereby alleviating pulmonary fibrosis. Moreover, in the context of asthma, the T helper cell 1/2 imbalance is restored by FA. Furthermore, FA ameliorates acute lung injury by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase pathways via toll-like receptor 4, consequently decreasing the expression of downstream inflammatory mediators. Additionally, there is a moderate neuraminidase inhibitory activity showing a tendency to reduce the interleukin-8 level in response to influenza virus infections. Although the application of FA has broad prospects, more preclinical mechanism-based research should be carried out to test these applications in clinical settings. This review not only covers the literature on the pharmacological effects and mechanisms of FA, but also discusses the therapeutic role and toxicology of FA in several pulmonary diseases.

Three new feruloyl glucuronopyranosyl glycerols from Eriocaulon buergerianum with their anti-fibrotic effects on hepatic stellate cells

Three new feruloyl glucuronopyranosyl glycerols, 1-O-α-D-(2'-feruloyl) glucuronopyranosyl glycerol (1), 1-O-α-D-(3'-feruloyl) glucuronopyranosyl glycerol (2), and 1-O-α-D-(4'-feruloyl) glucuronopyranosyl glycerol (3) were isolated and purified from the capitulum of Eriocaulon buergerianum Koern. Their structures were identified by spectroscopic and chemical methods. Molecular docking study showed that 1 is a potential inhibitor of TGF-β1 receptor. Bioassay results revealed that 1 exhibited strong inhibitory activity against the TGF-β-induced expression of α-smooth muscle actin (α-SMA) and fibronectin in human hepatic stellate LX-2 cells. The results in this study indicated that the new feruloyl glucuronopyranosyl glycerol 1 has preventive and therapeutic potentials against hepatic fibrosis.

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.

Ferulic acid: A review of its pharmacology, pharmacokinetics and derivatives

Ferulic acid, a kind of phenolic substance widely existing in plants, is an important active component of many traditional Chinese medicines. So far, it has been proved that ferulic acid has a variety of biological activities, especially in oxidative stress, inflammation, vascular endothelial injury, fibrosis, apoptosis and platelet aggregation. Many studies have shown that ferulic acid can inhibit PI3K/AKT pathway, the production of ROS and the activity of aldose reductase. The anti-inflammatory effect of ferulic acid is mainly related to the levels of PPAR γ, CAM and NF-κ B and p38 MAPK signaling pathways. Ferulic acid not only protects vascular endothelium by ERK1/2 and NO/ET-1 signal, but also plays an anti-fibrosis role by TGF-β/Smad and MMPs/TIMPs system. Moreover, ferulic acid has ant-apoptotic and anti-platelet effects. In addition to the pharmacological effects of ferulic acid, its pharmacokinetics and derivatives were also discussed in this paper. This review provides the latest summary of the latest research on ferulic acid.

Astragaloside IV Synergizing with Ferulic Acid Ameliorates Pulmonary Fibrosis by TGF-β1/Smad3 Signaling

OBJECTIVE

The study aims to research the interventional effect and mechanism of astragaloside IV (Ast) synergizing with ferulic acid (FA) on idiopathic pulmonary fibrosis (IPF) induced by bleomycin in mice.

METHODS

The mice were randomly divided into seven groups with 10 mice in each group, namely, a sham operation group, a model group, a miRNA-29b (miR-29) group, a miR-29b negative control group (NC group), a FA group, an Ast group, and a combination group. A mouse model of pulmonary fibrosis was established by intratracheal instillation of bleomycin. Samples were collected after 28 days of continuous administration. Hematoxylin and eosin (HE) and Masson staining were used to observe pathological changes in the lung tissue, and the degree of fibrosis was evaluated using the hydroxyproline content. Changes in transforming growth factor-β1 (TGF-β1) and Smad3 in the lung were observed using immunohistochemistry. Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) in the serum. PCR was used to detect the expression of the miR-29b, TGF-β1, Smad3, and nuclear factor E2-related factor 2 (Nrf2) genes. Western blotting was used to detect the content of the TGF-β/Smad3 protein.

RESULTS

Ferulic acid combined with astragaloside IV reduced the degree of pulmonary fibrosis and the synthesis of hydroxyproline in lung tissue. The combination of the two also regulated the oxidative stress response ， TGF-β1/Smad3 pathway and miR-29b in lung tissue.

CONCLUSION

Astragaloside IV combined with ferulic acid regulated the oxidative stress of lung tissues and TGF-β1/Smad3 signaling through miR-29b, thereby reducing the degree of pulmonary fibrosis. This provides a reference direction for the clinical treatment of IPF patients.

Astragaloside IV Synergizes with Ferulic Acid to Alleviate Hepatic Fibrosis in Bile Duct-Ligated Cirrhotic Rats

BACKGROUND

Due to the multi-factorial etiology of hepatic fibrosis, multi-target therapeutics based on combinatory drugs is known to be a promising strategy for the disease.

AIMS

The present study attempted to test the hypothesis that astragaloside IV combined with ferulic acid synergistically inhibits activation of hepatic stellate cells in vivo.

METHODS

Bile duct-ligated rats were treated with astragaloside IV or/and ferulic acid for 28 days. Liver fibrosis was measured by histological examination. The oxidative stress-related biomarkers were measured with spectrophotometry. Expressions of mRNA and protein were measured by real-time PCR and Western blotting.

RESULTS

Bile duct-ligated rat treatment with astragaloside IV and ferulic acid in combination resulted in synergistic alleviation of hepatic fibrosis. Simultaneously, activation of hepatic stellate cells was significantly inhibited by the combination therapy when compared with astragaloside IV or ferulic acid alone. Interestingly, astragaloside IV, but not ferulic acid, induced accumulation of Nrf2 in the nucleus, synthesized antioxidant enzymes through negative regulation of glycogen synthase kinase-3β, scavenged reactive oxygen species, and, in turn, suppressed hepatic stellate cells activation in bile duct-ligated rats. Conversely, ferulic acid, but not astragaloside IV, suppressed TGF-β1 and its receptors expression, which resulted in downregulation of Smad3 and Smad4.

CONCLUSIONS

These findings suggest that the combination of astragaloside IV and ferulic acid synergistically induces deactivation of hepatic stellate cells through inhibition of the TGF-β pathway and activation of the Nrf2 pathway, and suggest that combination of astragaloside IV and ferulic acid is a promising candidate for the treatment of hepatic fibrosis.

Chronic pelvic pain syndrome: Highlighting medicinal plants toward biomolecules discovery for upcoming drugs formulation

Chronic pelvic pain syndrome (CPPS) can be triggered by a various types of gynecological, gastrointestinal, urological, and musculoskeletal disorders. Recently, the role of the central nervous system has proven to be an integral part on the development of any chronic pain syndrome, including CPPS. However, owing to the complex and heterogeneous etiology and pathophysiology of CPPS, the establishment of effective therapeutic interventions remains challenging for both physicians and patients. Nonetheless, recent studies have pointed that medicinal plants and their secondary metabolites can be effectively used in CPPS therapy, besides contributing to restore the patients' quality of life and potentiate the conventional CPPS management. In this sense, this review aims to provide a careful overview on the biomedical data for the use of medicinal plants use and their secondary metabolites on CPPS management.

miR-21 promotes proliferation and inhibits apoptosis of hepatic stellate cells through targeting PTEN/PI3K/AKT pathway

To investigate the effect of microRNA 21 (miR-21) on hepatic stellate cells (HSCs) proliferation and apoptosis, and further to study its potential mechanisms. LX-2 cells were divided into miR-21 mimic group (Mimic), miR-21 mimic negative control group (NM), miR-21 inhibitor group (Inhibitor), miR-21 inhibitor negative control group (NC), and blank control group (Control). The cell proliferation was detected by CCK-8 assay and the cell migration and invasion were detected by scratch and transwell assay. Cell cycle and apoptosis were detected by flow cytometry. The levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β1 were detected by enzyme-linked immunosorbent assay (ELISA). Proliferation, apoptosis, and phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway related genes and proteins were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. The cells proliferation, migration, and invasion were promoted in Mimic group. The levels of IL-6, TNF-α, and TGF-β1 were increased after miR-21 administration. The expression of α-smooth muscle actin (SMA) and collagen 1 (Colla1) were increased, while Bax/B-cell lymphoma (Bcl)-2 ratio and programed cell death 4 (PDCD4) were reduced after miR‑21 treatment. Meanwhile, the mRNA and protein expression of PTEN were reduced and PI3K/AKT pathway been promoted. Our study demonstrated that miR-21 could promote proliferation and inhibit apoptosis of HSCs, and its mechanism may be related to PTEN/PI3K/AKT pathway.

Cadmium induces actin cytoskeleton alterations and dysfunction in Neuro-2a cells

Cadmium (Cd) is considered a possible etiological factor in neurodegenerative diseases. However, the exact mechanism by which Cd induces neurotoxicity is not well elucidated. In this study, Neuro-2a cells were treated with 0, 10, 20, and 40 μM cadmium chloride for 24 hours to investigate the effects of Cd on the cytoskeleton of nerve cells. MTT assay and ELISA assay were used to examine cell viability and release of lactate dehydrogenase (LDH) from cells, respectively. Results showed that Cd reduced cell viability and increased the release of LDH in a dose-dependent manner (P < 0.05). The morphology of treated cell was damaged as indicated by cell collapse and dimensionality reduction. Moreover, the axonal spines and normal features of Cd-treated neurons disappeared. We checked the ultrastructure of Neuro-2a cells and found that Cd-induced swelling, membrane damage, overflow of cytoplasm contents, and cell fragmentation. Damaged mitochondria, expanded endoplasmic reticulum, and abnormal microfilaments were found in Cd-treated cells rather than in untreated cells. Compared with the control group, the relative release of glutamate in the supernatant after Cd treatment was reduced, indicating that Cd exposure could reduce the release of glutamate by inhibiting the function of nerve-2a cells. Cd decreased the mRNA and protein expression levels of cytoskeletal proteins including DBN, SYP, and TAU, which might promote cytoskeleton alterations in Cd-treated cells. In conclusion, Cd-induced actin cytoskeleton alterations and dysfunction of cultured neurons. The results of the present study provide new insights for the investigation of Cd-induced neurotoxicity.

Emodin suppresses activation of hepatic stellate cells through p38 mitogen-activated protein kinase and Smad signaling pathways in vitro

The aim of this study was to evaluate the hypothesis that emodin inhibits extracellular matrix (ECM)-related gene expression in activated hepatic stellate cells (HSCs) by blocking canonical or/and noncanonical components of transforming growth factor β1 (TGFβ1) intracellular signaling. Here, we demonstrate that emodin suppressed the gene expression of HSCs activation markers type I collagen, fibronectin, and α-smooth muscle actin, as well as HSCs proliferation. Mechanistically, emodin suppresses TGFβ1, TGFβ receptor II, TGFβ receptor I, and Smad4 gene expression, as well as Smad luciferase activity. Simultaneously, emodin reduced p38 mitogen-activated protein kinase (p38^MAPK ) activity but not c-Jun N-terminal kinases and extracellular signal-regulated kinases 1 and 2 phosphorylation in HSC-T6 cells. Interestingly, deprivation of TGFβ using a neutralizing antibody abolished emodin-mediated inhibitions of the both Smad transcriptional activity and p38^MAPK phosphorylation. Furthermore, emodin-mediated inhibition of HSCs activation could be partially blocked by PD98059 inhibition of p38^MAPK or short hairpin RNA-imposed knockdown of Smad4. Conversely, simultaneous inhibition of Smad4 and p38^MAPK pathways completely reverses the effects of emodin, suggesting that Smad and p38^MAPK locate downstream of TGFβ1 and regulate collagen genes expression in HSCs. Collectively, these data suggest that emodin is a promising candidate for the treatment of hepatic fibrosis.

Flavonoids, Sterols and Lignans from Cochlospermum vitifolium and Their Relationship with Its Liver Activity

The sterols β-sitostenone (1), stigmast-4,6,8(14),22-tetraen-3-one (2), β-sitosterol (3) and stigmasterol (4), the aromatic derivatives antiarol (5) and gentisic acid (6), the phenylpropanes coniferyl alcohol (7), epoxyconiferyl alcohol (8) and ferulic acid (9), the apocarotenoid vomifoliol (10), the flavonoids naringenin (11), 7,4′-dimethoxytaxifolin (7,4′-dimethoxydihydroquercetin, 12), aromadendrin (13), kaempferol (14), taxifolin (dihydroquercetin, 15), prunin (naringenin-7-O-β-d-glucoside, 16), populnin (kaempferol-7-O-β-d-glucoside, 17) and senecin (aromadendrin-7-O-β-d-glucoside, 18) and the lignans kobusin (19) and pinoresinol (20), were isolated from the dried bark of Cochlospermum vitifolium Spreng (Cochlospermaceae), a Mexican medicinal plant used to treat jaundice, liver ailments and hepatitis C. Fourteen of these compounds were isolated for the first time from this plant and from the Cochlospermum genus. Compounds 3–4, 6–7, 9–11, 13–17 and 20 have previously exhibited diverse beneficial liver activities. The presence of these compounds in C. vitifolium correlates with the use of this Mexican medicinal plant.

Caveolin-1 Scaffolding Domain Peptides Alleviate Liver Fibrosis by Inhibiting TGF-β1/Smad Signaling in Mice

Liver fibrosis is the common pathological process characterized by activation of hepatic stellate cells (HSCs) and overproduction of extracellular matrix (ECM). Caveolin-1 (Cav1), the principal component of caveolae, is regarded as an important inhibitor of multiple signaling molecules including transforming growth factor β1(TGF-β1) signaling. To evaluate the role of Cav1 in liver fibrosis, Cav1 deficient (Cav1^−/−) and wild type (WT) mice were subjected to liver fibrosis induced by carbon tetrachloride (CCl₄). Results indicated no significant difference between Cav1^−/− and WT mice in inflammation or collagen content before CCl₄ treatment. After CCl₄ administration, Cav1^−/− mice showed enhanced TGF-β1 signaling, as reflected by a significantly greater amount of phosphorylation of Smad2 and collagen deposition in livers over WT animals. Qualitative and quantitative analysis indicated that inflammatory injury to the liver was markedly aggravated, accompanied by increased degeneration and necrosis of hepatocytes, higher alanine aminotransferase (ALT)/aspartate aminotransferase (AST), TGF-α and IL-1β levels in Cav1^−/− animals. The mRNA and protein levels of α-smooth muscle actin (α-SMA), Collagen α1(I), and Collagen α1(III) were further enhanced in Cav1^−/− animals. We also observed a significant decrease in collagen content in Cav1^−/− and WT animals administrated with Cav1 scaffolding domain peptides (CSD). In vitro study indicated that phosphorylation of Smad2 was inhibited after CSD treatment, accompanied by decreased protein levels of α-SMA, Collagen α1(I), and Collagen α1(III) in HSCs. We conclude that Cav1 is an important inhibitor of TGF-β1/Smad signaling in HSCs activation and collagen production, which might make it a promising target for therapy of liver fibrosis.

Rosmarinic acid attenuates β-amyloid-induced oxidative stress via Akt/GSK-3β/Fyn-mediated Nrf2 activation in PC12 cells

Oxidative stress is an important pathogenic factor in Alzheimer's disease (AD). Recently, nuclear factor E2-related factor 2 (Nrf2) has emerged as a master regulator for the endogenous antioxidant response, and thus represents an attractive therapeutic target against AD. The aim of this study is to test the hypothesis that rosmarinic acid (RosA) attenuates amyloid-β (Aβ)-evoked oxidative stress through activating Nrf2-inducible cellular antioxidant defense system. Here, we reported that RosA attenuated Aβ-induced cellular reactive oxygen species (ROS) generation and lipid hydroperoxides (LPO). Interestingly, knockdown of Nrf2 by plasmid-based short hairpin RNA (shRNA) abrogated, at least in part, RosA-mediated neuroprotection in Aβ-challenged PC12 cells. Mechanistically, RosA enhanced the nuclear translocation of Nrf2 and binding to antioxidant response element (ARE) core element but did not induced Nrf2 transcription. Simultaneously, RosA induced a set of Nrf2 downstream target genes encoding phase-II antioxidant enzymes. Furthermore, RosA enhanced protein kinase B (Akt) phosphorylation, glycogen synthase kinase-3β (GSK-3β) phosphorylation at Ser9, and Fyn phosphorylation. Noteworthy, pharmacological inhibition or gene knockdown studies demonstrated that Akt locate upstream of GSK-3β and regulate Nrf2 through Fyn in the context of PC12 cells pre-incubated with RosA following exposed to Aβ. Conversely, the antioxidant effects of RosA could be blocked by Akt inhibitors LY294002, GSK-3β inhibitor LiCl, Nrf2 shRNA, or Fyn shRNA in Aβ-challenged PC12 cells. Consequently, the antioxidant effects of RosA are mediated predominantly by Akt/GSK-3β/Fyn pathway through increased activity of Nrf2. These results suggest, although do not prove, that RosA can be a promising candidate for neuroprotective treatment of AD.

Exploring the Mechanism of Dangguiliuhuang Decoction Against Hepatic Fibrosis by Network Pharmacology and Experimental Validation

Dangguiliuhuang decoction (DGLHD) has been demonstrated to be effective in treating inflammatory, hepatic steatosis, and insulin resistance. In the study, we tried to elucidate the pharmacological efficacy and mechanism of DGLHD against liver fibrosis and predicate potential active ingredients and targets via network analysis and experimental validation. In the formula, we totally discovered 76 potential active ingredients like baicalein, berberine, and wogonin, and 286 corresponding targets including PTGS (prostaglandin-endoperoxide synthase) 2, PPAR (peroxisome proliferator-activated receptors) -γ, and NF-κB (nuclear factor-κB). Pathway and functional enrichment analysis of these putative targets indicated that DGLHD obviously influenced NF-κB and PPAR signaling pathway. Consistently, DGLHD downregulated levels of ALT (alanine transaminase) and AST (aspartate transaminase), reduced production of proinflammatory cytokines-TNF (tumor necrosis factor) -α and IL (Interleukin) -1β in serum and liver from mice with hepatic fibrosis, and inhibited hepatic stellate cell (HSC)-T6 cells proliferation. DGLHD decreased TGF (transforming growth factor) -β1 and α-SMA (smooth muscle actin) expression as well, maintained MMP (matrix metalloprotein) 13-TIMP (tissue inhibitor of metalloproteinases) 1 balance, leading to mitigated ECM (extracellular matrix) deposition in vivo and in vitro. Moreover, our experimental data confirmed that the alleviated inflammation and ECM accumulation were pertinent to NF-κB inhibition and PPAR-γ activation. Overall, our results suggest that DGLHD aims at multiply targets and impedes the progression of hepatic fibrosis by ameliorating abnormal inflammation and ECM deposition, thereby serving as a novel regimen for treating hepatic fibrosis in clinic.

Molecular targets of dietary phytochemicals for possible prevention and therapy of uterine fibroids: Focus on fibrosis

Uterine fibroids (myomas or leiomyomas) are common benign tumors of reproductive aged women. Fibroids are clinically apparent in 20-50% of women, and cause abnormal uterine bleeding, abdominal pain and discomfort, pregnancy complications and infertility. Unfortunately, limited numbers of medical treatment are available but no effective preventive strategies exist. Moreover, the benefits of medical treatments are tempered by lack of efficacy or serious adverse side effects. Fibrosis has recently been recognized as a key pathological event in leiomyoma development and growth. It is defined by the excessive deposition of extracellular matrix (ECM). ECM plays important role in making bulk structure of leiomyoma, and ECM-rich rigid structure is believed to be a cause of abnormal bleeding and pelvic pain/pressure. Dietary phytochemicals are known to regulate fibrotic process in different biological systems, and being considered as potential tool to manage human health. At present, very few dietary phytochemicals have been studied in uterine leiomyoma, and they are mostly known for their antiproliferative effects. Therefore, in this review, our aim was to introduce some dietary phytochemicals that could target fibrotic processes in leiomyoma. Thus, this review could serve as useful resource to develop antifibrotic drugs for possible prevention and treatment of uterine fibroids.

Isorhynchophylline Attenuates MPP+-Induced Apoptosis Through Endoplasmic Reticulum Stress- and Mitochondria-Dependent Pathways in PC12 Cells: Involvement of Antioxidant Activity

Endoplasmic reticulum stress (ERS) and mitochondrial dysfunctions are thought to be involved in the dopaminergic neuronal death in Parkinson's disease (PD). In this study, we found that isorhynchophylline (IRN) significantly attenuated 1-methyl-4-phenylpyridinium (MPP⁺)-induced apoptotic cell death and oxidative stress in PC12 cells. IRN markedly reduced MPP⁺-induced-ERS responses, indicative of inositol-requiring enzyme 1 (IRE1) phosphorylation and caspase-12 activation. Furthermore, IRN inhibits MPP⁺-triggered apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal Kinase (JNK) signaling-mediated mitochondria-dependent apoptosis pathway. IRN-mediated attenuation of endoplasmic reticulum modulator caspase-12 activation was abolished by diphenyleneiodonium (DPI) or IRE-1α shRNA, but not by SP600125 or pifithrin-α in MPP⁺-treated PC12 cells. Inhibitions of MPP⁺-induced both cytochrome c release and caspase-9 activation by IRN were blocked by pre-treatment with DPI or pifithrin-α, but not by IRE-1α shRNA. IRN blocks the generation of reactive oxygen species upstream of both ASK1/JNK pathway and IRE1/caspase-12 pathway. Altogether, our in vitro findings suggest that IRN possesses potent neuroprotective activity and may be a potential candidate for the treatment of PD.

ENMD-1068 inhibits liver fibrosis through attenuation of TGF-β1/Smad2/3 signaling in mice

Protease-activated receptor 2 (PAR-2) plays an important role in the pathogenesis of liver fibrosis. We studied the effect of N1-3-methylbutyryl-N4-6-aminohexanoyl-piperazine (ENMD-1068), a PAR-2 antagonist, on the development of CCl₄-induced liver fibrosis in mice and activation of hepatic stellate cells (HSCs) isolated from the mice. Before CCl₄ injection, the mice were injected intraperitoneally with either 25 mg/kg or 50 mg/kg ENMD-1068 or with 200 μL of the vehicle control twice per week for 4 weeks. The isolated HSCs were stimulated by TGF-β1 with or without ENMD-1068 to evaluate the role of PAR-2 in TGF-β1 induced HSCs activation and collagen production. We showed that the levels of ALT/AST, collagen content, and α-smooth muscle actin (α-SMA) were significantly reduced by treatment with ENMD-1068 in CCl₄-induced fibrotic mice. Interestingly, we found TGF-β1 signaling-related expression levels of α-SMA, type I and III collagen, and C-terminal phosphorylation of Smad2/3 were significantly decreased in the ENMD-1068 treated HSCs. Moreover, we showed ENMD-1068 treatment inhibited trypsin or SLIGRL-NH₂ stimulated calcium release and TGF-β1 induced Smad transcriptional activity in HSCs. We demonstrated that ENMD-1068 reduces HSCs activation and collagen expression through the inhibiton of TGF-β1/Smad signal transduction.

Astragaloside IV attenuates lead acetate-induced inhibition of neurite outgrowth through activation of Akt-dependent Nrf2 pathway in vitro

Recently, oxidative stress is strongly associated with lead (Pb)-induced neurotoxicity. We reported previously that Astragaloside IV (AS-IV) possesses potent antioxidant properties. Here, we evaluate the hypothesis that AS-IV attenuates lead acetate (PbAc)-mediated inhibition of neurite outgrowth might mainly result from its antioxidant property via serine/threonine protein kinase (Akt)-dependent activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Interestingly, AS-IV attenuates PbAc-induced inhibition of neurite outgrowth and displayed potential antioxidant properties by inhibiting reactive oxygen species (ROS). Concomitantly, AS-IV enhanced phase II detoxifying enzymes such as heme oxygenase 1 (HO-1), thioredoxin reductase (TrxR), and glutamate cysteine ligase catalytic subunit (GCLc). Conversely, AS-IV had no effect on GCL modulatory subunit (GCLm) and superoxide dismutase (SOD) activity/expression. Furthermore, AS-IV evoked Akt phosphorylation, and subsequent induced phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser9 (that is, inactivation), which stimulated Nrf2-mediated antioxidant response element (ARE)-containing activation. Importantly, Akt locates upstream of GSK-3β and regulates phase II detoxifying enzymes gene expression through Nrf2 nuclear accumulation in PC12 cells exposed to PbAc. Noteworthy, these results were further confirmed through signalling pathway inhibitors, dominant negative mutant and short hairpin RNA technology. Collectively, these in vitro findings suggest that AS-IV attenuates PbAc-induced inhibition of neurite outgrowth attributed to its antioxidant properties and may be a promising candidate for the treatment of lead developmental neurotoxicity.

Rosmarinic acid counteracts activation of hepatic stellate cells via inhibiting the ROS-dependent MMP-2 activity: Involvement of Nrf2 antioxidant system

Recently, oxidative stress is involved in hepatofibrogenesis. Matrix metalloproteinase-2 (MMP-2) is required for activation of hepatic stellate cells (HSCs) in response to reactive oxygen species (ROS). This study was designed to explore the hypothesis that the inhibitory effect of rosmarinic acid (RA) on HSCs activation might mainly result from its antioxidant capability by increasing the synthesis of glutathione (GSH) involved in nuclear factor kappa B (NF-κB)-dependent inhibition of MMP-2 activity. Here, we demonstrate that RA reverses activated HSCs to quiescent cells. Concomitantly, RA inhibits MMP-2 activity. RNA interference-imposed knockdown of NF-κB abolished down-regulation of MMP-2 by RA. RA-mediated inactivation of NF-κB could be blocked by the diphenyleneiodonium chloride (DPI; a ROS inhibitor). Conversely, transfection of dominant-negative (DN) mutant of extracellular signal-regulated kinases 2 (ERK2), c-Jun N-terminal kinase 1 (JNK1), or p38α kinase had no such effect. Simultaneously, RA suppresses ROS generation and lipid peroxidation (LPO) whereas increases cellular GSH in HSC-T6 cells. Furthermore, RA significantly increased antioxidant response element (ARE)-mediated luciferase activity, nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and catalytic subunits from glutamate cysteine ligase (GCLc) expression, but not modulatory subunits from GCL (GCLm). RA-mediated up-regulation of GClc is inhibited by the shRNA-induced Nrf2 knockdown. The knocking down of Nrf2 or buthionine sulfoximine (a GCL inhibitor) abolished RA-mediated inhibition of ROS. Collectively, these results provide novel insights into the mechanisms of RA as an antifibrogenic candidate in the prevention and treatment of liver fibrosis.

Astragaloside IV synergizes with ferulic acid to suppress hepatic stellate cells activation in vitro

Because hepatic fibrosis usually involves more than one pathological process, combination therapy with modalities that target aberrant signaling cascade in activated hepatic stellate cells (HSCs) represents an alternative strategy. This study evaluates the hypothesis that astragaloside IV (AS-IV) and ferulic acid (FA) synergize to inhibit HSCs activation via simultaneous activating nuclear factor erythroid-2-related factor-2 (Nrf2) and blocking transforming growth factor-β (TGF-β) pathways. The combination of FA and AS-IV, hereafter referred to as the AS-IV/FA, at suboptimal concentrations synergistically inhibited HSCs activation, as measured by expressions of α-smooth muscle actin (α-SMA), collagen α type I (Col I) and fibronectin. Nrf2 nuclear accumulation, glutathione (GSH) increase, and reactive oxygen species (ROS) reduction by AS-IV were not potentiated by co-treatment with FA. Similarly, inhibition of TGF-β1 secretion and Smad activity by FA also was not enhanced by combined treatment with AS-IV. AS-IV/FA synergistically suppresses the p38 mitogen-activated protein kinase (MAPK) activity. Inhibition of HSCs activation by AS-IV/FA could be completely blocked by TGF-βs-neutralizing antibody plus shRNA-mediated knockdown of Nrf2. Dual blockade of the TGF-β1/Smad pathway by FA and activation of Nrf2/ARE pathway by AS-IV contributed to the synergistic effects of this combination treatment. These results suggest that combinatorial treatments that target different pathway may afford a more effective strategy to inhibit HSC activation.

Danggui Buxue Tang Attenuates Tubulointerstitial Fibrosis via Suppressing NLRP3 Inflammasome in a Rat Model of Unilateral Ureteral Obstruction

Inflammation significantly contributes to the progression of chronic kidney disease (CKD). This study aimed to characterize Danggui Buxue Tang (DBT) renoprotection and relationship with NOD-like receptors family pyrin domain-containing 3 (NLRP3) inflammasome expression in rats with unilateral ureteral obstruction (UUO). Sprague-Dawley rats were subjected to UUO and randomly assigned to untreated UUO, enalapril-treated (10 mg/kg/day), and DBT-treated (9 g/kg/day) groups. Sham-operated rats served as controls, with 8 rats in each group. All rats were sacrificed for blood and renal specimen collection at 14 days after UUO. Untreated UUO rats exhibited azotemia, intense tubulointerstitial collagen deposition, upregulations of tubulointerstitial injury index, augmentation levels of collagen I (Col I), α-smooth muscle actin (α-SMA), NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), pro-caspase-1, caspase-1, IL-1β, and pro-IL-1β. DBT treatment significantly attenuated interstitial collagen deposition and tubulointerstitial injury, lowering Col I and α-SMA levels. Synchronous expressions of NLRP3, ASC, pro-caspase-1, caspase-1, pro-IL-1β, and IL-1β decreased in renal tissue. In comparison to enalapril, DBT significantly reduced tubulointerstitial injury, interstitial collagen deposition, and expressions of Col I and IL-1β. Thus, DBT offers renoprotection in UUO rats, which was associated with suppressing NLRP3 inflammasome expression and following reduction of the secretion of cytokine IL-1β. The mechanisms of multitargets of traditional Chinese medicine can be better used for antifibrotic treatment.

Xia-yu-xue decoction (XYXD) reduces carbon tetrachloride (CCl4)-induced liver fibrosis through inhibition hepatic stellate cell activation by targeting NF-κB and TGF-β1 signaling pathways

Background

Hepatic stellate cell (HSC) activation is activated mainly by endotoxin and transforming growth factor (TGF-β1) in chronic liver injury, consequently, can be important therapeutic targets. Xia-yu-xue decoction (XYXD), a classical recipe used in China to treat liver fibrosis, and has been revealed to inhibit hepatic fibrosis in animal models, the mechanism of action of XYXD remains elusive. In the present study, we evaluated whether XYXD reduced endotoxin and pro-fibrogenic pathways induced by lipopolysaccharide (LPS) and TGF-β1 in HSCs.

Methods

The in vivo effect of XYXD on fibrosis progression was assessed in mice model induced by carbon tetrachloride (CCl₄), The in vitro effect of XYXD on mice GFP-Col-HSC cells was evaluated using LPS and TGF-β1 stimulation.

Results

XYXD treatment reduced CCl₄-induced liver fibrosis and decreased hepatic hydroxyproline (Hyp) content, the mRNA levels of smooth muscle actin (α-SMA) and Col 1(α1) in fibrotic liver. XYXD suppressed nuclear factor-κB (NF-κB) activation induced by LPS and TGF-β1 assessed by using NF-κB-luciferase reporter. The expression of NF-κB target genes, chemokine (C-C motif) ligand 2 (CCL2) and chemokine (C-X-C motif) ligand 2 (CXCL2) induced by LPS was suppressed after XYXD treatment. The expression of TGF-β1 targets genes, Col1(α1) and tissue inhibitor of metalloproteinases (TIMP1) induced by TGF-β1 was inhibit after XYXD treatment.

Conclusion

XYXD treatment attenuates liver fibrosis by inhibiting HSC activation via inhibition of NF-κB and TGF-β1 signaling pathway, thereby blocking the synthesis of Col1 (α1) and TIMP-1. These findings from present study suggest that XYXD may be a therapeutic decoction for liver fibrosis in which NF-κB and TGF-β1 are thought to take part.