Radix Glycyrrhizae extract and licochalcone a exert an anti-inflammatory action by direct suppression of toll like receptor 4.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Glycyrrhizae (GL), a herbal medicine that is widely available, has shown advantages for a variety of inflammatory diseases. Toll like receptor 4 (TLR4) pathway has been shown to play a key role in the progression of inflammation. AIM OF THE STUDY: The purpose of this study was to investigate the involvement of TLR4 in the anti-inflammatory mechanism of GL extract and its active constituent on acute lung injury (ALI). MATERIALS AND METHODS: A model of inflammation produced by lipopolysaccharide (LPS) was established in C57BL/6 mice and macrophages derived from THP-1. To screen the active components of GL, molecular docking was used. Molecular dynamics and surface plasmon resonance imaging (SPRi) were used to study the interaction of a specific drug with the TLR4-MD2 complex. TLR4 was overexpressed by adenovirus to confirm TLR4 involvement in the anti-inflammatory activities of GL and the chosen chemical. RESULTS: We observed that GL extract significantly reduced both LPS-induced ALI and the production of pro-inflammatory factors including TNF-α, IL-6 and IL-1ß. Additionally, GL inhibited the binding of Alexa 488-labeled LPS (LPS-488) to the membrane of THP-1 derived macrophages. GL drastically reduce on the expression of TLR4 and the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-B (NF-κB). Furthermore, molecular docking revealed that Licochalcone A (LicoA) docked into the LPS binding site of TLR4-MD2 complex. MD2-LicoA binding conformation was found to be stable using molecular dynamic simulations. SPRi indicated that LicoA bound to TLR4-MD2 recombinant protein with a KD of 3.87 × 10-7 M. LicoA dose-dependently reduced LPS-488 binding to the cell membrane. LicoA was found to significantly inhibit LPS-induced lung damage and inflammation. Furthermore, LicoA inhibited TLR4 expression, MAPK and NF-κB activation in a dose-dependent manner. The inhibitory effects of GL and LicoA on LPS-induced inflammation and TLR4 signaling activation were partly eliminated by TLR4 overexpression. CONCLUSION: Our findings imply that GL and LicoA exert inhibitory effects on inflammation by targeting the TLR4 directly.

Calycosin protects against oxidative stress-induced cardiomyocyte apoptosis by activating aldehyde dehydrogenase 2.

Myocardial infarction (MI) is the leading cause of death worldwide, and oxidative stress is part of the process that causes MI. Calycosin, a naturally occurring substance with cardioprotective properties, is one of the major active constituents in Radix Astragali. In this study, effect of Calycosin was investigated in vivo and in vitro to determine whether it could alleviate oxidative stress and oxidative stress-induced cardiac apoptosis in neonatal cardiomyocytes (NCMs) via activation of aldehyde dehydrogenase 2 (ALDH2). Calycosin protected against oxidative stress and oxidative stress-induced apoptosis in NCMs. Molecular docking revealed that the ALDH2-Calycosin complex had a binding energy of -9.885 kcal/mol. In addition, molecular docking simulations demonstrated that the ALDH2-Calycosin complex was stable. Using BLI assays, we confirmed that Calycosin could interact with ALDH2 (KD  = 1.9 × 10-4 M). Furthermore, an ALDH2 kinase activity test revealed that Calycosin increased ALDH2 activity, exhibiting an EC50 of 91.79 µM. Pre-incubation with ALDH2 inhibitor (CVT-10216 or disulfiram) reduced the cardio-protective properties Calycosin. In mice with MI, Calycosin therapy substantially reduced myocardial apoptosis, oxidative stress, and activated ALDH2. Collectively, our findings clearly suggest that Calycosin reduces oxidative stress and oxidative stress-induced apoptosis via the regulation of ALDH2 signaling, which supports potential therapeutic use in MI.

10-Gingerol, a natural AMPK agonist, suppresses neointimal hyperplasia and inhibits vascular smooth muscle cell proliferation.

Background: Abnormal proliferation of vascular smooth muscle cells (VSMCs) in the intimal region is a key event in the development of neointimal hyperplasia. 10-G, a bioactive compound found in ginger, exerted inhibitory effects on the proliferation of several cancer cells. However, the effect and mechanism of 10-G on neointimal hyperplasia are not clear. Purpose: To explore the suppressive effects of 10-G on the proliferation and migration of VSMCs, and investigate the underlying mechanisms. Methods: In vivo, a left common carotid artery ligation mouse model was used to observe the effects of neointimal formation through immunohistochemistry and hematoxylin-eosin staining. In vitro, the cell proliferation and migration of HASMCs and A7r5 cells were detected by MTS assay, EdU staining, wound healing assay, Transwell assay, and western blotting as well. Molecular docking, molecular dynamics simulations and surface plasmon resonance imaging were collectively used to evaluate the interaction of 10-G with AMP-activated protein kinase (AMPK). Compound C and si-AMPK were used to inhibit the expression of AMPK. Results: Treatment with 10-G significantly reduced neointimal hyperplasia in the left common carotid artery ligation mouse model. MST and EdU staining showed that 10-G inhibited the proliferation of VSMC cells A7r5 and HASMC. We also found that 10-G altered the expression of proliferation-related proteins, including CyclinD1, CyclinD2, CyclinD3, and CDK4. Molecular docking revealed that the binding energy between AMPK and 10-G is -7.4 kcal mol-1. Molecular simulations suggested that the binding between 10-G and AMPK is stable. Surface plasmon resonance imaging analysis also showed that 10-G has a strong binding affinity to AMPK (KD = 6.81 × 10-8 M). 10-G promoted AMPKα phosphorylation both in vivo and in vitro. Blocking AMPK by an siRNA or AMPK inhibitor pathway partly abolished the anti-proliferation effects of 10-G on VSMCs. Conclusion: These data showed that 10-G might inhibit neointimal hyperplasia and suppress VSMC proliferation by the activation of AMPK as a natural AMPK agonist.

Dihydrotanshinone I inhibits the growth of hepatoma cells by direct inhibition of Src.

BACKGROUND: Liver cancer is one of the leading causes of cancer-related death worldwide. Dihydrotanshinone I (DHI) was shown to inhibit the growth of several types of cancer. However, research related to hepatoma treatment using DHI is limited. PURPOSE: Here, we explored the inhibitory effect of DHI on the growth of hepatoma cells, and investigated the underlying molecular mechanisms. METHODS: The proliferation of Hep3B, SMCC-7721 and SK-Hep1 hepatoma cells was evaluated using the MTS and Edu staining assay. Hepatoma cell death was analyzed with a LIVE/DEAD Cell Imaging Kit. The relative expression and phosphorylation of proto-oncogene tyrosine-protein kinase Src (Src) and signal transducer and activator of transcription-3 (STAT3) proteins in hepatoma cells, as well as the expression of other protein components, were measured by western blotting. The structural interaction of DHI with Src proteins was evaluated by molecular docking, molecular dynamics simulation, surface plasmon resonance imaging and Src kinase inhibition assay. Src overexpression was achieved by infection with an adenovirus vector encoding human Src. Subsequently, the effects of DHI on tumor growth inhibition were further validated using mouse xenograft models of hepatoma. RESULTS: In vitro studies showed that treatment with DHI inhibited the proliferation and promoted cell death of Hep3B, SMCC-7721 and SK-Hep1 hepatoma cells. We further identified and verified Src as a direct target of DHI by using molecular stimulation, surface plasmon resonance image and Src kinase inhibition assay. Treatment with DHI reduced the in vitro phosphorylation levels of Src and STAT3, a transcription factor regulated by Src. In the xenograft mouse models, DHI dose-dependently suppressed tumor growth and Src and STAT3 phosphorylation. Moreover, Src overexpression partly abrogated the inhibitory effects of DHI on the proliferation and cell death in hepatoma cells. CONCLUSION: Our results suggest that DHI inhibits the growth of hepatoma cells by direct inhibition of Src.

Dauricine inhibits proliferation and promotes death of melanoma cells via inhibition of Src/STAT3 signaling.

Melanoma is the most common type of skin cancer. Signal transducer and activator of transcription 3 (STAT3) signaling has been demonstrated to be a therapeutic target for melanoma. Dauricine (Dau), an alkaloid compound isolated from the root of Menispermum dauricum DC., has shown tumor-suppressing effects in multiple human cancers, but its potential in melanoma remains unexplored. In this study, we demonstrated that Dau significantly inhibited the viability and proliferation of A375 and A2058 melanoma cells. Death of melanoma cells was also markedly promoted by Dau. Moreover, Dau inhibited phosphorylation-mediated activation of STAT3 and Src in a dose-dependent manner. Notably, constitutive activation of Src partially abolished the antiproliferative and cytotoxic activities of Dau on melanoma cells. Molecular docking showed that Dau could dock on the kinase domain of Src with a binding energy of -10.42 kcal/mol. Molecular dynamics simulations showed that Src-Dau binding was stable. Surface plasmon resonance imaging analysis also showed that Dau has a strong binding affinity to Src. In addition, Dau suppressed the growth of melanoma cells and downregulated the activation of Src/STAT3 in a xenograft model in vivo. These data demonstrated that Dau inhibits proliferation and promotes cell death in melanoma cells by inhibiting the Src/STAT3 pathways.