Sodium pyruvate exerts protective effects against cigarette smoke extract-induced ferroptosis in alveolar and bronchial epithelial cells through the GPX4/Nrf2 axis.

BACKGROUND: Ferroptosis in alveolar and bronchial epithelial cells is one of the main mechanisms underlying the development of chronic obstructive pulmonary disease (COPD). Sodium pyruvate (NaPyr) is a natural antioxidant in the body, exhibiting anti-inflammatory and antioxidant activities. NaPyr has been used in a Phase II clinical trial as a novel therapy for COPD; however, the mechanism underlying NaPyr-mediated therapeutic benefits in COPD is not well understood. OBJECTIVE: We aimed to assess the protective effects of NaPyr and elucidate its potential mechanism in cigarette smoke extract (CSE)-induced ferroptosis.To minic the inflammatory response and ferroptosis triggered by cigarette smoke in COPD in an invitro cell based system, we expose a human bronchial epithelial cells to CSE. METHODS: To minic the inflammatory response and ferroptosis triggered by cigarette smoke in COPD in an invitro cell based system, the A549 (human lung carcinoma epithelial cells) and BEAS-2B (bronchial epithelial cells) cell lines were cultured, followed by treatment with CSE. To measure cellular viability and iron levels, we determined the levels of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS), mitochondrial superoxide (MitoSOX), membrane potential (MMP), and inflammatory factors (tumor necrosis factor [TNF] and interleukin [IL]-8), and examined CSE-induced pulmonary inflammation and ferroptosis. To clarify the molecular mechanisms of NaPyr in COPD therapy, we performed western blotting and real-time PCR (qPCR) to determine the expression of glutathione peroxidase 4 (GPX4), nuclear factor E2-related factor 2 (Nrf2), and cyclooxygenase 2 (COX2). RESULTS: We found that NaPyr effectively mitigated CSE-induced apoptosis and improved apoptosis induced by erastin, a ferroptosis inducer. NaPyr significantly decreased iron and MDA levels and increased GSH levels in CSE-induced cells. Furthermore, NaPyr suppressed ferroptosis characteristics, such as decreased levels of ROS, MitoSOX, and MMP. NaPyr significantly increases the expression levels of GPX4 and Nrf2, indicating that activation of the GPX4/Nrf2 axis could inhibit ferroptosis in alveolar and bronchial epithelial cells. More importantly, NaPyr inhibited the secretion of downstream inflammatory factors, including TNF and IL-8, by decreasing COX2 expression levels to suppress CSE-induced inflammation. CONCLUSION: Accordingly, NaPyr could mitigate CSE-induced ferroptosis in alveolar and bronchial epithelial cells by activating the GPX4/Nrf2 axis and decreasing COX2 expression levels. In addition, NaPyr reduced the secretion of inflammatory factors (TNF and IL-8), affording a novel therapeutic candidate for COPD.

The indole alkaloids from the roots of Isatidis Radix.

The root of Isatis indigotica is used as a traditional Chinese medicine (termed Isatidis Radix) due to its antiviral effects. We examined compounds isolated from Isatidis Radix and elucidated the structures of three new natural alkaloids, and we examined the possible mechanisms or active targets of indole alkaloids occurring in blood of rats treated by gavage. Three new natural products were isolated from Radix Isatidis for the first time, including 1-methoxy-2-indoleacetonitrile, 1-hydroxy-3-indoleacetonitrile, 8-Methoxy-1, 2-dihydroquinoline, and 4 compounds isolated from this medicinal material for the first time. Their structures were elucidated using nuclear magnetic resonance. The components of Isatidis Radix were analysed using liquid chromatography tandem mass spectrometry, and 33 compounds were detected in plasma of treated rats; 24 of these compounds were indole alkaloids, and they included the newly identified compounds. Molecular docking and in vitro antithrombin activity tests showed HA inhibition activity of indoleacetonitriles.

Indole-3-carboxaldehyde regulates RSV-induced inflammatory response in RAW264.7 cells by moderate inhibition of the TLR7 signaling pathway.

Human respiratory syncytial virus (RSV) is highly contagious and the leading cause of severe respiratory tract illness in infants, elderly, and immunocompromised individuals. Toll-like receptor 7 (TLR7), a pattern recognition receptor recognising the ssRNA of RSV, activates proinflammatory pathways and triggers secretion of interferons (IFNs). On the one hand, the inflammatory responses help clear out virus. On the other hand, they lead to severe lung damage. Banlangen is a traditional Chinese herbal medicine commonly prescribed for respiratory virus infection treatment, but the mechanisms of action and active components remain largely unknown. In the present study, we investigated the effects of the main active components of total alkaloids from banlangen (epigoitrin, indole-3-carboxaldehyde, indole-3-acetonitrile and 4-methoxyindole-3-acetonitrile) on the RSV-induced inflammatory responses in mouse macrophage cells (RAW264.7). Our results demonstrated that RSV-induced IFN-α excessive secretion was moderately inhibited by indole-3-carboxaldehyde through downregulation of mRNA expression in a dose-dependent manner, in comparison, the inhibitory effects of ribavirin were too strong. Furthermore, we revealed that indole-3-carboxaldehyde suppressed transcription of IFN-α by inhibiting RSV-induced TLR7 expression in RAW264.7 cells. Additionally, indole-3-carboxaldehyde inhibited RSV-induced NF-κB signalling activation in a TLR7-MyD88-dependent manner. Together, our findings suggest that indole-3-carboxaldehyde inhibited RSV-induced inflammatory injury by moderate regulation of TLR7 signaling pathway and did not significantly affect the viral clearance competence of the innate immune system.

Different types of effective fractions from Radix Isatidis revealed a multiple-target synergy effect against respiratory syncytial virus through RIG-I and MDA5 signaling pathways, a pilot study to testify the theory of superposition of traditional Chinese Medicine efficacy.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Isatidis, a commonly used traditional Chinese medicine, is also documented in "Dictionary of Chinese Ethnic Medicine" being as an ethnic herb clinically utilized by different nations in China such as Mongol, Uygur, and Dong et al. It has been reported to have a very strong efficacy on respiratory viruses, but to date the mechanism remains unknown. Similarly, it is unclear how different types of effective fractions of Radix Isatidis interact to exert antiviral effects. AIM OF STUDY: To reveal the underlying mechanisms for the inhibitory effects of three active fractions from Radix Isatidis, i.e. total alkaloids, lignans and organic acids, on respiratory syncytial virus when used alone or in combination. In addition, we investigated whether these three parts worked synergistically in vivo and in vitro. MATERIALS AND METHODS: A mouse model of RSV infection was constructed by intranasal infection, and the pathological changes of lung tissues in different parts were observed. The level changes of IFNß and inflammatory cytokines in the mouse alveolar lavage fluid were detected by enzyme-linked immunosorbent assay (ELISA). The anti-RSV effects of different effective fractions were evaluated by the plaque reduction test. The mRNA and protein expressions of RIG-I, MDA-5, MAVS and IRF3 in RAW264.7 cells were detected by RT-PCR and Western blot respectively. RESULTS: HE staining showed that Radix Isatidis extracts alone or in combination relieved virus-induced mouse lung lesions. Compared with individual drugs, the lung lesions were alleviated more significantly after treatment with the three fractions in combination. ELISA demonstrated that the expression levels of IFNß and inflammatory cytokines were maintained balanced between antiviral and proinflammatory effects. The plaque reduction test indicated that the antiviral effect of combination treatment was much stronger than those of individual drugs. RT-qPCR and Western blot suggested that the mRNA and protein expression levels of key signaling molecules in the RIG-I and MDA5 pathways in mouse macrophages were down-regulated by different effective parts alone or in combination. CONCLUSIONS: The three effective fractions of Radix Isatidis have remarkable synergistic anti-RSV effects in vitro and in vivo, and total alkaloids and lignans show multi-target synergistic effects via the RIG-I and MDA5 signaling pathways.

Resveratrol inhibits VEGF-induced angiogenesis in human endothelial cells associated with suppression of aerobic glycolysis via modulation of PKM2 nuclear translocation.

Endothelial cells (ECs) mainly depend on aerobic glycolysis to generate angiogenesis. Deregulation of glycolysis is often observed in human endothelial cells during angiogenesis. In the present study, we first report that resveratrol (RST), which has been intensively studied in glucose metabolism of various cancer cells, has a profound inhibitory effect on tube formation and migration via suppression of glycolysis in human umbilical vein endothelial cells (HUVECs) induced by vascular endothelial growth factor (VEGF). Moreover, we further reveal that RST reduced the mRNA and protein level of glucose transporter-1(GLUT1), hexokinase II (HK2), phosphofructokinase-1(PFK1) and pyruvate kinase M2 (PKM2) through modulation of ERK-mediated PKM2 nuclear translocation. Our results provide a novel mechanism to account for the inhibition of RST on VEGF-mediated angiogenesis and suggest that targeting aerobic glycolysis or nuclear PKM2 may be a new approach for pathological angiogenesis prevention or treatment.

4(3H)-Quinazolone regulates innate immune signaling upon respiratory syncytial virus infection by moderately inhibiting the RIG-1 pathway in RAW264.7 cell.

The root of Isatis indigotica, also known as Ban-Lan-Gen (BLG), is commonly used for prevention and early treatment of respiratory virus infection, but the underlying mechanisms of action remain unclear. In the early stage of infection, the innate immune system is activated by virus, and related immune cells such as macrophages secrete large amounts of cytokines including IFNs and ILs. On the one hand, these cytokines can remove virus. On the other hand, they dominantly mediate the inflammatory injury caused by viral infection. This study evaluated the effects of the main active plasma components of BLG (tryptanthrin B, 4(3H)-Quinazolone and epigoitrin) on the innate immune response of respiratory syncytial virus (RSV)-activated mouse macrophages. ELISA, real-time PCR and reporter gene assay all showed that 4(3H)-Quinazolone inhibited RSV-induced IFN-ß secretion in mouse macrophages in a dose-dependent manner within a concentration range (0.3125-1.25µM) having no effects on cell viability, but the inhibitory effects were inferior to those of ribavirin. Western blot analyses further revealed that 4(3H)-Quinazolone inhibited RSV-induced expression of RIG-I (Retinoic acid-Inducible Gene-I) in mouse macrophages dose-dependently, thereby suppressing the transcription of IFN-ß, with lower effects than those of ribavirin. This may be one of the important mechanisms by which BLG inhibited inflammatory injury without affecting the immune system to eliminate virus. The results inspire future studies to elucidate the antiviral mechanisms of traditional Chinese medicine drugs.

Resveratrol suppresses pulmonary tumor metastasis by inhibiting platelet-mediated angiogenic responses.

BACKGROUND: To explore the impact of Resveratrol (RSV) on the angiogenic potential of activated platelets and to elucidate the underlying mechanism. METHODS: Vascular endothelial growth factor concentrations were measured by enzyme-linked immunosorbent assay. Capillary tube formation assay was used to examine the impact of RSV on the angiogenic potential of activated platelets. The levels of cyclic adenosine monophosphate and cyclic guanosine monophosphate (cGMP) in the supernatant were evaluated using corresponding enzyme-linked immunosorbent assay kits. Immunoblotting assays were used to determine the expression of vasodilator-stimulated phosphoprotein and Akt phosphorylation. A pulmonary metastasis experiment with male nude mice model was performed to test the effect of RSV on pulmonary metastasis and angiogenesis in vivo. RESULTS: RSV inhibited platelets-mediated angiogenic responses induced by adenosine diphosphate (ADP)ADP through increased cGMP generation and cGMP-mediated vasodilator-stimulated phosphoprotein phosphorylation along with reduced intracellular Ca2+ mobilization. In addition, RSV attenuated the platelet secretion and angiogenic responses induced by A549 cells in vitro and suppressed A549 lung cancer metastasis and angiogenesis in nude mice. CONCLUSIONS: RSV is a potential therapeutic drug for the prevention of tumor metastasis by interrupting the platelet-tumor cell amplification loop.

Nuclear PKM2 expression, an independent risk factor for ER after curative resection of hepatocellular carcinoma.

Surgical resection, providing a long-term survival of hepatocellular carcinoma (HCC) patients, is regarded as one of the standard curative treatments of HCC if the tumor is resectable. However, 50% patients develop early recurrence (ER) during the first two years after operation, which are more diffuse and rarely treatable with unsatisfactory long-term survival. Unfortunately, the underlying mechanisms of ER after curative resection and the molecular markers with predictive and prognostic significance have never been identified yet. Recent studies reveal that pyruvate kinase M2 (PKM2) levels were correlated with overall survival and disease-free survival in patients with HCC. The present study was aimed to investigate the correlation between the expression of PKM2 and ER. Our findings demonstrated that not the total PKM2 expression but the nuclear PKM2 expression as an independent risk factor for ER after curative resection, and could be a promising intervention target following curative resection for HCC patients.

Quercetin stimulates mitochondrial apoptosis dependent on activation of endoplasmic reticulum stress in hepatic stellate cells.

CONTEXT: Activation of hepatic stellate cells (HSCs) is a hallmark of liver fibrosis. Quercetin has benefits for liver fibrosis, but the mechanisms are unknown. OBJECTIVE: We investigated the quercetin effect on HSC survival and the role of endoplasmic reticulum stress (ERS). MATERIALS AND METHODS: Rat HSCs and LO2 hepatocytes were treated with quercetin (0.5-120 µM) for 24 h. Quercetin (10-40 µM) effects on apoptosis for 24 h were analyzed by flow cytometry and TUNEL staining. Quercetin (10-40 µM) effects on the expression of Bcl-2, caspase-9, caspase-3, PARP-1, PERK, IRE1, ATF6, calnexin and CHOP for 24 h were analyzed by Western blot. Quercetin (10-40 µM) effects on mRNA expression of calnexin and CHOP for 24 h were analyzed by Real-time PCR. RESULTS: Quercetin at concentrations greater than 20 µM significantly inhibited HSC proliferation (IC50 27.2 µM), but did not affect hepatocyte growth until 80 µM (IC50 68.5 µM). Quercetin stimulated HSC apoptosis and the apoptotic rate reached 40% at a concentration of 40 µM (EC50 51.6 µM). Quercetin induced downregulation of Bcl-2 and upregulation of Bax, and increased cytochrome C in the cytoplasm in HSCs. The cleaved forms of caspase-9, caspase-3 and PARP-1 were also increased by quercetin. Furthermore, quercetin elevated mRNA and protein expression of calnexin and CHOP in HSCs but not in hepatocytes. Quercetin also increased phosphorylation of PERK and IRE1 and ATF6 cleavage. However, ERS inhibitor salubrinal significantly abrogated quercetin induction of HSC apoptosis. CONCLUSION: Quercetin activated ERS pathway in HSCs leading to apoptosis. We characterized an ERS-mediated mechanism for quercetin as a promising antifibrotic agent.