Luteolin inhibits viral-induced inflammatory response in RAW264.7 cells via suppression of STAT1/3 dependent NF-κB and activation of HO-1

Mechanisms of Luteolin Against Gastro-Esophageal Reflux Disease Based on Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Luteolin is a naturally occurring flavonoid. The effectiveness of luteolin-rich drugs in treating gastro-esophageal reflux disease (GERD) through traditional Chinese medicine has been demonstrated. This study aimed to identify the potential targets and mechanisms of action of luteolin for the treatment of GERD. An innovative approach combining network pharmacology and molecular dynamics was used to explore the potential therapeutic mechanisms of luteolin and to facilitate the further development of GERD treatment. Drug and disease target information was screened from public databases to obtain 159 intersecting targets through the construction of Venn diagrams. Subsequently, a protein‒protein interaction (PPI) network was constructed, and 10 core targets were identified. Through Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, relevant biological processes, cellular components, and molecular functions related to the treatment of GERD were identified and revealed. KEGG pathway analyses showed enrichment of signaling pathways, including the TNF, IL-17, NF-kappa B, and Toll-like receptor pathways. The molecular docking results indicated that luteolin can effectively bind to 10 core targets. Finally, molecular dynamics simulations confirmed the formation of stable protein‒ligand complexes when IL6 binds to luteolin. In conclusion, network pharmacology, molecular docking, and molecular dynamics simulations were utilized to investigate the mechanism by which luteolin treats GERD. These findings establish a theoretical foundation for future research on the efficacy of luteolin in treating GERD.

Antiviral activity of luteolin against porcine epidemic diarrhea virus in silico and in vitro

BACKGROUND

Porcine epidemic diarrhea virus (PEDV) mainly causes acute and severe porcine epidemic diarrhea (PED), and is highly fatal in neonatal piglets. No reliable therapeutics against the infection exist, which poses a major global health issue for piglets. Luteolin is a flavonoid with anti-viral activity toward several viruses.

RESULTS

We evaluated anti-viral effects of luteolin in PEDV-infected Vero and IPEC-J2 cells, and identified IC50 values of 23.87 µM and 68.5 µM, respectively. And found PEDV internalization, replication and release were significantly reduced upon luteolin treatment. As luteolin could bind to human ACE2 and SARS-CoV-2 main protease (Mpro) to contribute viral entry, we first identified that luteolin shares the same core binding site on pACE2 with PEDV-S by molecular docking and exhibited positive pACE2 binding with an affinity constant of 71.6 µM at dose-dependent increases by surface plasmon resonance (SPR) assay. However, pACE2 was incapable of binding to PEDV-S1. Therefore, luteolin inhibited PEDV internalization independent of PEDV-S binding to pACE2. Moreover, luteolin was firmly embedded in the groove of active pocket of Mpro in a three-dimensional docking model, and fluorescence resonance energy transfer (FRET) assays confirmed that luteolin inhibited PEDV Mpro activity. In addition, we also observed PEDV-induced pro-inflammatory cytokine inhibition and Nrf2-induced HO-1 expression. Finally, a drug resistant mutant was isolated after 10 cell culture passages concomitant with increasing luteolin concentrations, with reduced PEDV susceptibility to luteolin identified at passage 10.

CONCLUSIONS

Our results push forward that anti-PEDV mechanisms and resistant-PEDV properties for luteolin, which may be used to combat PED.

Luteolin-incorporated fish collagen hydrogel scaffold: An effective drug delivery strategy for wound healing

In clinical practice, wound care has always been challenging. Hydrogels play a key role in facilitating active wound recovery by absorbing exudates, maintaining moisture, and alleviating pain through cooling. In this study, type I collagen was isolated from the skin of crucian carp (Carassius carassius) and verified by amino acid analysis, FTIR, and SDS-PAGE. By adopting a new approach, luteolin was added to collagen hydrogels in situ after being dissolved in an alkaline solution. XRD and SEM confirmed the luteolin was incorporated and entirely distributed throughout the hydrogel. The plastic compression improved the young's modulus of hydrogel to 15.24 ± 0.59 kPa, which is adequate for wound protection. The drug loading efficiency was 98 ± 1.47 % in the selected formulation. The luteolin-incorporated hydrogel enabled regulated drug release. We assessed the cytotoxicity using MTT and live-dead assays, as well as examined the hemocompatibility to determine the biocompatibility of the hydrogel. In vivo experiments showed that the hydrogel with luteolin had the highest wound closure rate (94.01 ± 2.1 %) and improved wound healing with granular tissue formation, collagen deposition, and re-epithelialization. These findings indicate that this efficient drug delivery technology can accelerate the process of wound healing.

An investigation into the HIF-dependent intestinal barrier protective mechanism of Qingchang Wenzhong decoction in ulcerative colitis management

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is a chronic, non-specific inflammatory disease affecting the colon and rectum with an etiology that remains elusive. Traditional Chinese medicine (TCM) has been widely used on long-term UC treatment to better maintain the efficacy than traditional aminosalicylic acid or glucocorticosteroids and to ease financial burden of patients. Qingchang Wenzhong Decoction (QCWZD) is a modern TCM decoction with established clinical efficacy but the mechanism of its protection on intestinal barrier function remains unclear.

AIM OF THE STUDY

Current findings highlight that the activation of the hypoxia inducible factor (HIF) pathway can facilitate the repair of intestinal epithelium barrier. This study is to investigate the protective effects of QCWZD and its HIF-targeted ingredients on hypoxia-dependent intestinal barrier.

METHODS

The mice model of UC was induced by dextran sulfate sodium (DSS). Disease activity index (DAI) and histopathology scores and colon length were used to measure the severity of colitis. The DAO activity in serum and protein expression of tight junction (TJ) proteins were detected to explore the function of intestinal barrier. The protein levels of HIF-1α and its downstream gene heme oxygenase-1 (HO-1) were measured as well. HIF-targeted active ingredients in QCWZD were selected by network pharmacology and molecular docking. Protective effects of six constituents on HIF-related anti-oxidative and barrier protective pathway were evaluated by lipopolysaccharide (LPS)-induced HT29 and RAW264.7 cells, through the measurement of the production of ROS and mRNA level of pro-inflammatory cytokines. HIF-1α knockdown was carried out to explore the correlation of protection effects with HIF-related pathway of the active ingredients.

RESULTS

QCWZD effectively alleviated colitis induced by DSS and demonstrated a protective effect on intestinal barrier function by upregulating HIF-related pathways. Six specific ingredients in QCWZD, targeting HIF, successfully reduced the production of cellular ROS and proinflammatory cytokines in LPS-induced cells. It is noteworthy that the barrier protection provided by these molecules is intricately linked with the HIF-related pathway.

CONCLUSIONS

This study elucidates the HIF-related molecular mechanism of QCWZD in protecting the function of the epithelial barrier. Six compounds targeting the activation of the HIF-dependent pathway were demonstrated to unveil a novel therapeutic approach for managing UC.

Pyrogallol protects against influenza A virus-triggered lethal lung injury by activating the Nrf2-PPAR-γ-HO-1 signaling axis

Pyrogallol, a natural polyphenol compound (1,2,3-trihydroxybenzene), has shown efficacy in the therapeutic treatment of disorders associated with inflammation. Nevertheless, the mechanisms underlying the protective properties of pyrogallol against influenza A virus infection are not yet established. We established in this study that pyrogallol effectively alleviated H1N1 influenza A virus-induced lung injury and reduced mortality. Treatment with pyrogallol was found to promote the expression and nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor gamma (PPAR-γ). Notably, the activation of Nrf2 by pyrogallol was involved in elevating the expression of PPAR-γ, both of which act synergistically to enhance heme oxygenase-1 (HO-1) synthesis. Blocking HO-1 by zinc protoporphyrin (ZnPP) reduced the suppressive impact of pyrogallol on H1N1 virus-mediated aberrant retinoic acid-inducible gene-I-nuclear factor kappa B (RIG-I-NF-κB) signaling, which thus abolished the dampening effects of pyrogallol on excessive proinflammatory mediators and cell death (including apoptosis, necrosis, and ferroptosis). Furthermore, the HO-1-independent inactivation of janus kinase 1/signal transducers and activators of transcription (JAK1/STATs) and the HO-1-dependent RIG-I-augmented STAT1/2 activation were both abrogated by pyrogallol, resulting in suppression of the enhanced transcriptional activity of interferon-stimulated gene factor 3 (ISGF3) complexes, thus prominently inhibiting the amplification of the H1N1 virus-induced proinflammatory reaction and apoptosis in interferon-beta (IFN-β)-sensitized cells. The study provides evidence that pyrogallol alleviates excessive proinflammatory responses and abnormal cell death via HO-1 induction, suggesting it could be a potential agent for treating influenza.

Effects and Mechanisms of Luteolin, a Plant-Based Flavonoid, in the Prevention of Cancers via Modulation of Inflammation and Cell Signaling Molecules

Luteolin, a flavonoid, is mainly found in various vegetables and fruits, including carrots, cabbages, onions, parsley, apples, broccoli, and peppers. Extensive research in vivo and in vitro has been performed to explore its role in disease prevention and treatment. Moreover, this compound possesses the ability to combat cancer by modulating cell-signaling pathways across various types of cancer. The studies have confirmed that luteolin can inhibit cancer-cell survival and proliferation, angiogenesis, invasion, metastasis, mTOR/PI3K/Akt, STAT3, Wnt/β-catenin, and cell-cycle arrest, and induce apoptosis. Further, scientific evidence describes that this compound plays a vital role in the up/down-regulation of microRNAs (miRNAs) in cancer therapy. This review aims to outline the anti-cancer mechanisms of this compound and its molecular targets. However, a knowledge gap remains regarding the studies on its safety and efficacy and clinical trials. Therefore, it is essential to conduct more research based on safety, efficacy, and clinical trials to explore the beneficial role of this compound in disease management, including cancer.

Natural products in anti-tuberculosis host-directed therapy

Given that the disease progression of tuberculosis (TB) is primarily related to the host's immune status, it has been gradually realized that chemotherapy that targets the bacteria may never, on its own, wholly eradicate Mycobacterium tuberculosis, the causative agent of TB. The concept of host-directed therapy (HDT) with immune adjuvants has emerged. HDT could potentially interfere with infection and colonization by the pathogens, enhance the protective immune responses of hosts, suppress the overwhelming inflammatory responses, and help to attain a state of homeostasis that favors treatment efficacy. However, the HDT drugs currently being assessed in combination with anti-TB chemotherapy still face the dilemmas arising from side effects and high costs. Natural products are well suited to compensate for these shortcomings by having gentle modulatory effects on the host immune responses with less immunopathological damage at a lower cost. In this review, we first summarize the profiles of anti-TB immunology and the characteristics of HDT. Then, we focus on the rationale and challenges of developing and implementing natural products-based HDT. A succinct report of the medications currently being evaluated in clinical trials and preclinical studies is provided. This review aims to promote target-based screening and accelerate novel TB drug discovery.

From nature to therapy: Luteolin's potential as an immune system modulator in inflammatory disorders

Inflammation is an essential immune response that helps fight infections and heal tissues. However, chronic inflammation has been linked to several diseases, including cancer, autoimmune disorders, cardiovascular diseases, and neurological disorders. This has increased interest in finding natural substances that can modulate the immune system inflammatory signaling pathways to prevent or treat these diseases. Luteolin is a flavonoid found in many fruits, vegetables, and herbs. It has been shown to have anti-inflammatory effects by altering signaling pathways in immune cells. This review article discusses the current research on luteolin's role as a natural immune system modulator of inflammatory signaling mechanisms, such as its effects on nuclear factor-kappa B, mitogen-activated protein kinases, Janus kinase/signal transducer and activator of transcription, and inflammasome signaling processes. The safety profile of luteolin and its potential therapeutic uses in conditions linked to inflammation are also discussed. Overall, the data point to Luteolin's intriguing potential as a natural regulator of immune system inflammatory signaling processes. More research is needed to fully understand its mechanisms of action and possible therapeutic applications.

Early depletion of M1 macrophages retards the progression of glucocorticoid-associated osteonecrosis of the femoral head

Inflammation stands as a pivotal factor in the pathogenesis of glucocorticoid-associated osteonecrosis of the femoral head (GA-ONFH). However, the vital role played by M1 macrophages, the principal constituents of the inflammatory process, remains largely underexplored. In this study, we employed reverse transcription-quantitative polymerase chain Reaction (RT-PCR), western blot, and flow cytometry to assess the impact of M1-conditioned medium on cultures of mouse bone marrow-derived mesenchymal stem cells (BMSCs) and Murine Long bone Osteocyte-Y4 (MLO-Y4) in vitro. Moreover, we quantified the levels of inflammatory cytokines in the M1-conditioned medium through the employment of an enzyme-linked immunosorbent assay (ELISA). For in vivo analysis, we examined M1 macrophages and investigated the NF-kB signaling pathway in specimens obtained from the femoral heads of animals and humans. We found that the number of M1 macrophages in the femoral head of GA-ONFH patients grew significantly, and in the mice remarkably increase, maintaining high levels in the intramedullary. In vitro, the M1 macrophage-conditioned medium elicited apoptosis in BMSCs and MLO-Y4 cells, shedding light on the intricate interplay between macrophages and these cell types. The presence of TNF-α within the M1-conditioned medium activated the NF-κB pathway, providing mechanistic insight into the apoptotic induction. Moreover, employing a robust rat macrophage clearance model and GA-ONFH model, we demonstrated a remarkable attenuation in TNF-α expression and NF-kB signaling subsequent to macrophage clearance. This pronounced reduction engenders diminished cellular apoptosis and engenders a decelerated trajectory of GA-ONFH progression. In conclusion, our study reveals the crucial involvement of M1 macrophages in the pathogenesis of GA-ONFH, highlighting their indispensable role in disease progression. Furthermore, early clearance emerges as a promising strategy for impeding the development of GA-ONFH.

Effects of luteolin on sepsis: A comprehensive systematic review

BACKGROUND

Sepsis and septic shock are the main causes of mortality and complications in intensive care units all over the world. Luteolin is thought to have a significant role as a free radical scavenger, an anti-inflammatory agent, and an immune system modulator. The object of this review is to conduct a systematic review of the effects of luteolin and its mechanisms of action in the treatment of sepsis and its complications.

METHOD

The investigation was carried out in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines (PROSPERO: CRD42022321023). We searched Embase, Web of Science, Google Scholar, Science Direct, PubMed, ProQuest, and Scopus databases up to  January 2023 by using the relevant keywords.

RESULTS

Out of 1,395 records screened, 33 articles met the study criteria. In the collected papers, the main reported findings are that luteolin can affect inflammation-initiating pathways such as toll-like receptors and high mobility group box-1 and reduces the expression of genes that produce inflammatory cytokines, such as the Nod receptor protein-3, and nuclear factor kappa-light chain-enhancer of activated B cells. Luteolin also reduces the overactivity of macrophages, neutrophil extracellular traps and lymphocytes by regulating the immune response.

CONCLUSION

Most studies revealed luteolin's positive benefits on sepsis through several pathways. Luteolin showed the capacity to reduce inflammation and oxidative stress, control immunological response, and prevent organ damage (in vivo studies) during sepsis. Large-scale in vivo experiments are necessary to elucidate its potential impacts on sepsis.

Highly pathogenic porcine reproductive and respiratory syndrome virus-induced inflammatory response in porcine pulmonary microvascular endothelial cells and effects of herbal ingredients on main inflammatory molecules

The role of microvascular endothelial cells (MVECs) in viral infection has received increasing attention. Our previous study demonstrated the susceptibility of porcine pulmonary MVECs to highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV), while their responses to the viral infection remain unclear. This study aimed to understand effects of the HP-PRRSV infection on functions of porcine pulmonary MVECs and the intervention effects of Chinese herbal ingredients on them. Highly purified porcine pulmonary MVECs were separated using CD31-immunomagnetic beads and infected with HP-PRRSV JXA1 and HN strain. The virus particles in cells and the ultrastructural pathological changes of cells were revealed by transmission electron microscopy. High-throughput transcriptome sequencing indicated that 104 and 228 genes were differentially expressed at 36 h post-infection, respectively, including many inflammatory molecules such as interleukins, chemokines, and adhesion molecules. The expression kinetics of HP-PRRSV-induced IL-1α, IL-6, IL-8, and VCAM-1 were characterized at the mRNA and protein levels. Luteolin significantly down-regulated HP-PRRSV-induced increase of the four molecules at both levels, and glycyrrhetinic acid and baicalin reduced that of IL-6 and VCAM-1. Our results suggest that porcine pulmonary MVECs play important roles in the inflammatory lung injury caused by HP-PRRSV infection and that herbal ingredients have potential regulatory effects on the HP-PRRSV-induced dysfunction of MVECs.

Mechanism for inhibition of cytotoxicity of Shiga toxin by luteolin

Enterohemorrhagic or Shiga toxin-producing Escherichia coli is a food-poisoning bacterium that grows in the intestine to produce Shiga toxin (Stx). In this study, the effects of 20 polyphenols on the cytotoxicity of Stx1 and Stx2 in Vero cells were investigated. Among these, epigallocatechin gallate, butein, isorhapontigenin, hesperetin, morin, luteolin, resveratrol, and rhapontigenin showed inhibitory effects on the cytotoxicity of Stxs at 0.4 mmol/L. Furthermore, Vero cells pre-treated with these polyphenols were resistant to Stx at 0.4 mmol/L. However, luteolin showed the most potent inhibitory and cytoprotective effect against Stxs at 0.08 mmol/L or more. This inhibitory mechanism of luteolin was determined using a cell-free protein synthesis system and quantitative reverse transcription PCR assay to detect depurination of 28S rRNA in Vero cells. Luteolin did not inhibit the cell-free protein synthesis by Stxs, suggesting that the enzymatic activity of the Stx A subunit was not inhibited by luteolin. The depurination of 28S rRNA by Stxs was also investigated in Vero cells. The 28S rRNA depurination by Stxs was suppressed in Vero cells treated with Stxs which had been pretreated with luteolin. These results suggest that luteolin inhibits the incorporation of Stxs into Vero cells. This is the first report to show that luteolin inhibits the cytotoxicity of both Stx1 and Stx2 by inhibiting the incorporation of Stxs into Vero cells.

Luteolin Attenuates APEC-Induced Oxidative Stress and Inflammation via Inhibiting the HMGB1/TLR4/NF-κB Signal Axis in the Ileum of Chicks

Avian pathogenic E. coli (APEC) is typically the cause of avian colibacillosis, which can result in oxidative stress, inflammation, and intestinal damage (APEC). Luteolin, in the form of glycosylation flavone, has potent anti-inflammatory and anti-oxidative properties. However, its effects on APEC-induced intestinal oxidative stress and NF-κB-mediated inflammation in chicks remains poorly understood. After hatching, one-day-old chicks were stochastically assigned to four groups: a control group (basic diet), an E. coli group (basic diet) and L10 and L20 groups (with a dry matter of luteolin diet 10 mg/kg and 20 mg/kg, respectively), with fifteen chicks in each group and one repeat per group. They were pretreated for thirteen days. The body weight, mortality, histopathological changes in the ileum, antioxidant status, and the mRNA and protein-expression levels of factors associated with the HMGB1/TLR4/NF-κB signal axis of the chicks were measured. The results showed that luteolin treatment decreased the mRNA and protein-expression level of the related factors of HMGB1/TLR4/NF-κB signal axis in the ileum, reduced inflammation, increased antioxidant enzyme activity, and reduced intestinal injury. Collectively, luteolin alleviated APEC-induced intestinal damage by means of hindering the HMGB1/TLR4/NF-κB signal axis, which suggests that luteolin could be a good method for the prevention and treatment of avian colibacillosis.

Luteolin alleviated damage caused by blue light to Drosophila

Short-wavelength blue light is commonly found in daily life and is harmful to health. In this experiment, we investigated the effect of luteolin on the survival time of Drosophila under the blue light condition of 3000 Lux using Drosophila as the model organism. The results showed that luteolin alleviated the damage suffered by Drosophila under blue light irradiation, significantly prolonged the survival time of Drosophila, prolonged the survival time of male Drosophila in the heat stress assay, increased the activity of female Drosophila in the spontaneous activity assay, and increased the egg production of female Drosophila at the highest concentration, and there was no significant difference in the food intake experiment. We suggest that the increase in survival time of Drosophila under blue light conditions is due to the function of luteolin in resisting oxidative stress.

Research Progress with Luteolin as an Anti-Tumor Agent

In this review, we outline the new expertise and research progress with luteolin as an antitumor agent, and clarify the related results from the aspects of tumor proliferation, apoptosis, invasion, metastasis, sensitivity to radiotherapy and chemotherapy, angiogenesis, and immunotherapy. In recent years, with the development of medical technology, the early detection rate of tumors has increased significantly. However, the number of cancer patients remains high. Therefore, a new and reasonably effective tumor therapeutic drug is urgently demanded. Luteolin, a flavonoid and widespread in nature, attracts more and more attention due to its universal biological utility, especially in the study of antitumor activity. This article reviews the work published in the past 20 years on the role and mechanism of luteolin as an antitumor agent, showing that this compound has a variety of effects for antitumor treatment by acting on different cytokines. Although clinical studies have not yet been widely carried out, a series of basic studies have confirmed that luteolin is a reasonably effective antineoplastic agent or anticancer adjuvant. Besides, derivatives of luteolin have good application prospects.

Flavonoids as Potential Antiviral Agents for Porcine Viruses

Flavonoids are types of natural substances with phenolic structures isolated from a variety of plants. Flavonoids have antioxidant, anti-inflammatory, anticancer, and antiviral activities. Although most of the research or applications of flavonoids are focused on human diseases, flavonoids also show potential applicability against porcine virus infection. This review focuses on the recent progress in antiviral mechanisms of potential flavonoids against the most common porcine viruses. The mechanism discussed in this paper may provide a theoretical basis for drug screening and application of natural flavonoid compounds and flavonoid-containing herbs to control porcine virus infection and guide the research and development of pig feed additives.

Progress of Research into Novel Drugs and Potential Drug Targets against Porcine Pseudorabies Virus

Pseudorabies virus (PRV) is the causative agent of pseudorabies (PR), infecting most mammals and some birds. It has been prevalent around the world and caused huge economic losses to the swine industry since its discovery. At present, the prevention of PRV is mainly through vaccination; there are few specific antivirals against PRV, but it is possible to treat PRV infection effectively with drugs. In recent years, some drugs have been reported to treat PR; however, the variety of anti-pseudorabies drugs is limited, and the underlying mechanism of the antiviral effect of some drugs is unclear. Therefore, it is necessary to explore new drug targets for PRV and develop economic and efficient drug resources for prevention and control of PRV. This review will focus on the research progress in drugs and drug targets against PRV in recent years, and discuss the future research prospects of anti-PRV drugs.

Potential Natural Biomolecules Targeting JAK/STAT/SOCS Signaling in the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by the dysregulation of cytokines and other immune mediators. JAK/STAT is a classical signal transduction pathway involved in various biological processes, and its dysregulation contributes to the key aspects of AD pathogenesis. Suppressor of cytokine signaling (SOCS) proteins negatively regulate the immune-related inflammatory responses mediated by the JAK/STAT pathway. JAK/STAT-mediated production of cytokines including IL-4, IL-13, IL-31, and TSLP inhibits the expression of important skin barrier proteins and triggers pruritus in AD. The expression of SOCS proteins regulates the JAK-mediated cytokines and facilitates maintaining the skin barrier disruptions seen in AD. STATs are crucial in dendritic-cell-activated Th2 cell differentiation in the skin, releasing inflammatory cytokines, indicating that AD is a Th2-mediated skin disorder. SOCS proteins aid in balancing Th1/Th2 cells and, moreover, regulate the onset and maintenance of Th2-mediated allergic responses by reducing the Th2 cell activation and differentiation. SOCS proteins play a pivotal role in inflammatory cytokine-signaling events that act via the JAK/STAT pathway. Therapies relying on natural products and derived biomolecules have proven beneficial in AD when compared with the synthetic regimen. In this review, we focused on the available literature on the potential natural-product-derived biomolecules targeting JAK/STAT/SOCS signaling, mainly emphasizing the SOCS family of proteins (SOCS1, SOCS3, and SOCS5) acting as negative regulators in modulating JAK/STAT-mediated responses in AD pathogenesis and other inflammatory disorders.

Prediction of the mechanism of Dachengqi Decoction treating colorectal cancer based on the analysis method of " into serum components -action target-key pathway"

ETHNOPHARMACOLOGICAL RELEVANCE

Colorectal cancer (CRC) is a common digestive tract malignant tumor that its morbidity and mortality seriously affect human health. At present, Dachengqi Decoction (DCQ), a traditional Chinese medicine formula, has been clinically used as an adjuvant therapy for CRC. However, pharmacodynamic substance basis and therapeutic mechanism are still unclear.

AIM OF THE STUDY

The main constituents absorbed in the blood and possible active targets after DCQ administration were explored based on the analysis method of "into serum components, action target and key pathway", which may provide reference for the study of the pharmacodynamic material basis and action mechanism of Dachengqi Decoction in the treatment of CRC.

MATERIAL AND METHODS

Based on the serum pharmacochemistry of traditional Chinese medicine (TCM), the prescription prototype ingredients of DCQ in mice serum samples were identified by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry technology (UPLC-Q-TOF-MS^E). Taking the prototype ingredients absorbed into serum as the research object, the possible targets and key pathways of DCQ in vivo were demonstrated by network pharmacology. Finally, using molecular docking verified the binding activity of prototype components and potential action targets.

RESULTS

A total of 46 prototype components of DCQ were identified in mice serum, most of which were derived from flavonoids and anthraquinones in Citrus aurantium L. and Rheum palmatum L. Network pharmacology prediction results indicated that the drug prototype components entering the serum may mainly regulate targets including mitogen-activated protein kinase (MAPK), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), etc. and main pathways such as (phosphatidylinositol 3-kinase/protein kinase B) PI3K-AKT signaling pathway, advanced glycation end products-receptor for AGE (AGE-RAGE) signaling pathway and IL-17 signaling pathway, etc. Molecular docking showed that the prototype active components had strong binding activity to VEGF, Harvey rat sarcoma viral oncogene homolog (HRAS) and MAPK1.

CONCLUSIONS

This study elucidated that most of the direct acting substances of DCQ in vivo were flavonoids and anthraquinones, which may play a role in regulating cell reproduction and apoptosis and inhibiting inflammation, providing a reference for the research of pharmacodynamic material basis and mechanism of DCQ in the treatment of CRC.

BMP9 reduces age-related bone loss in mice by inhibiting osteoblast senescence through Smad1-Stat1-P21 axis

Age-related osteoporosis is characterized by the accumulation of senescent osteoblastic cells in bone microenvironment and significantly reduced osteogenic differentiation. Clearing of the senescent cells is helpful to improve bone formation in aged mice. Bone morphogenetic protein 9 (BMP9), a multifunctional protein produced and secreted by liver, was reported to improve osteoporosis caused by estrogen withdrawal. However, the mechanism of BMP9 has not been fully elucidated, and its effect on senile osteoporosis has not been reported. This study reveals that BMP9 significantly increases bone mass and improves bone biomechanical properties in aged mice. Furthermore, BMP9 reduces expression of senescent genes in bone microenvironment, accompanied by decreased senescence-associated secretory phenotypes (SASPs) such as Ccl5, Mmp9, Hmgb1, Nfkb1, and Vcam1. In vitro, Bmp9 treatment inhibits osteoblast senescence through activating Smad1, which suppresses the transcriptional activity of Stat1, thereby inhibits P21 expression and SASPs production. Furthermore, inhibiting the Smad1 signal in vivo can reverse the inhibitory effect of BMP9 on Stat1 and downstream senescent genes, which eliminates the protection of BMP9 on age-related osteoporosis. These findings highlight the critical role of BMP9 on reducing age-related bone loss by inhibiting osteoblast senescence through Smad1-Stat1-P21 axis.

BMP9 inhibits cellular senescence by activation of Smad1, which suppresses the transcription of Stat1, resulting in decreased P21 expression and SASPs production in osteoblast. The anti-aging effect of BMP9 is benefit to improving age-related osteoporosis.

HO-1 Contributes to Luteolin-Triggered Ferroptosis in Clear Cell Renal Cell Carcinoma via Increasing the Labile Iron Pool and Promoting Lipid Peroxidation

Ferroptosis, a novel form of regulated cell death characterized by disrupted iron metabolism and the accumulation of lipid peroxides, has exhibited enormous potential in the therapy of cancer particularly clear cell renal cell carcinoma (ccRCC). Luteolin (Lut), a natural flavonoid widely existing in various fruits and vegetables, has been proven to exert potent anticancer activity in vitro and in vivo. However, previous studies on the anticancer mechanism of Lut have been shown in apoptosis but not ferroptosis. In the present study, we identified that Lut substantially inhibited the survival of ccRCC in vitro and in vivo, and this phenomenon was accompanied by excessively increased intracellular Fe2+ and abnormal depletion of GSH. In addition, Lut induced the imbalance of mitochondrial membrane potential, classical morphological alterations of mitochondrial ferroptosis, generation of ROS, and occurrence of lipid peroxidation in an iron-dependent manner in ccRCC cells. However, these alterations induced by Lut could be reversed to some extent by the iron ion chelator deferiprone or the ferroptosis inhibitor ferrostatin-1, indicating that ccRCC cells treated with Lut underwent ferroptosis. Mechanistically, molecular docking further established that Lut probably promoted the heme degradation and accumulation of labile iron pool (LIP) by excessively upregulating the HO-1 expression, which led to the Fenton reaction, GSH depletion, and lipid peroxidation in ccRCC, whereas blocking this signaling pathway evidently rescued the Lut-induced cell death of ccRCC by inhibiting ferroptosis. Altogether, the current study shows that the natural compound monomer Lut exerted anticancer efficacy by excessively upregulating HO-1 expression and activating LIP to trigger ferroptosis in ccRCC and could be a promising and potent drug candidate for ccRCC treatment.

Suppressive Effect of Tetrahydrocurcumin on Pseudomonas aeruginosa Lipopolysaccharide-Induced Inflammation by Suppressing JAK/STAT and Nrf2/HO-1 Pathways in Microglial Cells

Brain inflammation, a pathological feature of neurodegenerative disorders, exhibits elevated microglial activity and increased levels of inflammatory factors. The present study was aimed at assessing the anti-inflammatory response of tetrahydrocurcumin (THC), the primary hydrogenated metabolite of curcumin, which was applied to treat Pseudomonas aeruginosa (P.a.) lipopolysaccharide- (LPS-) stimulated BV2 microglial cells. THC reduced P.a. LPS–induced mortality and the production of inflammatory mediators IL-6, TNF-α, MIP-2, IP-10, and nitrite. A further investigation revealed that THC decreased these inflammatory cytokines synergistically with JAK/STAT signaling inhibitors. THC also increased Nrf2/HO-1 signaling transduction which inhibits iNOS/COX-2/pNFκB cascades. Additionally, the presence of the HO-1 inhibitor Snpp increased the levels of IP-10, IL-6, and nitrite while THC treatment reduced those inflammatory factors in P.a. LPS–stimulated BV2 cells. In summary, we demonstrated that THC exhibits anti-inflammatory activities in P.a. LPS-induced inflammation in brain microglial cells by inhibiting STAT1/3-dependent NF-κB activation and inducing Nrf2-mediated HO-1 expression.

A Tug of War: Pseudorabies Virus and Host Antiviral Innate Immunity

The non-specific innate immunity can initiate host antiviral innate immune responses within minutes to hours after the invasion of pathogenic microorganisms. Therefore, the natural immune response is the first line of defense for the host to resist the invaders, including viruses, bacteria, fungi. Host pattern recognition receptors (PRRs) in the infected cells or bystander cells recognize pathogen-associated molecular patterns (PAMPs) of invading pathogens and initiate a series of signal cascades, resulting in the expression of type I interferons (IFN-I) and inflammatory cytokines to antagonize the infection of microorganisms. In contrast, the invading pathogens take a variety of mechanisms to inhibit the induction of IFN-I production from avoiding being cleared. Pseudorabies virus (PRV) belongs to the family Herpesviridae, subfamily Alphaherpesvirinae, genus Varicellovirus. PRV is the causative agent of Aujeszky’s disease (AD, pseudorabies). Although the natural host of PRV is swine, it can infect a wide variety of mammals, such as cattle, sheep, cats, and dogs. The disease is usually fatal to these hosts. PRV mainly infects the peripheral nervous system (PNS) in swine. For other species, PRV mainly invades the PNS first and then progresses to the central nervous system (CNS), which leads to acute death of the host with serious clinical and neurological symptoms. In recent years, new PRV variant strains have appeared in some areas, and sporadic cases of PRV infection in humans have also been reported, suggesting that PRV is still an important emerging and re-emerging infectious disease. This review summarizes the strategies of PRV evading host innate immunity and new targets for inhibition of PRV replication, which will provide more information for the development of effective inactivated vaccines and drugs for PRV.

The Establishment of a Noninvasive Bioluminescence-Specific Viral Encephalitis Model by Pseudorabies Virus-Infected NF-κBp-Luciferase Mice

Encephalitis is a rare brain inflammation that is most commonly caused by a viral infection. In this study, we first use an in vivo imaging system (IVIS) to determine whether NF-κBp-luciferase expression could be detected in the brain of pseudorabies virus (PRV)-infected NF-κBp-luciferase mice and to evaluate proinflammatory mediators in a well-described mouse model of PRV encephalitis. In in vitro studies, we used murine microglia (BV-2) cells to demonstrate the PRV-induced encephalitis model entailing the activation of microglia cells. The results indicate that PRV-induced neuroinflammation responses through the induction of IL-6, TNF-α, COX-2, and iNOS expression occurred via the regulation of NF-κB expression in BV-2 cells. In in vivo studies, compared with MOCK controls, the mice infected with neurovirulent PRV exhibited significantly elevated NF-κB transcription factor activity and luciferase protein expression only in the brain by IVIS. Mild focal necrosis was also observed in the brain. Further examination revealed biomarkers of inflammation, including inducible cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), and tumor necrosis factor (TNF)-α and interleukin (IL)-6, both of which constituted proinflammatory cytokines. PRV infection stimulated inflammation and COX-2 and iNOS expression of IL-6 and TNF-α. The presented results herein suggest that PRV induces iNOS and COX-2 expression in the brain of NF-κBp–luciferase mice via NF-κB activation. In conclusion, we used NF-κBp-luciferase mice to establish a specific virus-induced encephalitis model via PRV intranasal infection. In the future, this in vivo model will provide potential targets for the development of new therapeutic strategies focusing on NF-κB inflammatory biomarkers and the development of drugs for viral inflammatory diseases.

A Newly Synthesized Flavone from Luteolin Escapes from COMT-Catalyzed Methylation and Inhibits Lipopolysaccharide-Induced Inflammation in RAW264.7 Macrophages via JNK, p38 and NF-κB Signaling Pathways

Luteolin is a common dietary flavone possessing potent anti-inflammatory activities. However, when administrated in vivo, luteolin becomes methylated by catechol-O-methyltransferases (COMT) owing to the catechol ring in the chemical structure, which largely diminishes its anti-inflammatory effect. In this study, we made a modification on luteolin, named LUA, which was generated by the chemical reaction between luteolin and 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). Without a catechol ring in the chemical structure, this new flavone could escape from the COMT-catalyzed methylation, thus affording the potential to exert its functions in the original form when administrated in the organism. Moreover, an LPS-stimulated RAW cell model was applied to detect the anti-inflammatory properties. LUA showed much more superior inhibitory effect on LPS-induced production of NO than diosmetin (a major methylated form of luteolin) and significantly suppressed upregulation of iNOS and COX-2 in macrophages. LUA treatment dramatically reduced LPS-stimulated reactive oxygen species (ROS) and mRNA levels of pro-inflammatory mediators such as IL-1β, IL-6, IL-8 and IFN-β. Furthermore, LUA significantly reduced the phosphorylation of JNK and p38 without affecting that of ERK. LUA also inhibited the activation of NF-κB through suppression of p65 phosphorylation and nuclear translocation.

The involvement of JAK/STAT signaling pathway in the treatment of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder in which inflammation and oxidative stress play key etiopathological role. The pathology of PD brain is characterized by inclusions of aggregated α-synuclein (α-SYN) in the cytoplasmic region of neurons. Clinical evidence suggests that stimulation of pro-inflammatory cytokines leads to neuroinflammation in the affected brain regions. Upon neuroinflammation, the Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signaling pathway, and other transcription factors such as nuclear factor κB (NF-κB), NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), mammalian target of rapamycin (mTOR), and toll-like receptors (TLRs) are upregulated and induce the microglial activation, contributing to PD via dopaminergic neuron autophagy. Aberrant activation or phosphorylation of the components of JAK/STAT signaling pathway has been implicated in increased transcription of the inflammation-associated genes and many neurodegenerative disorders such as PD. Interferon gamma (IFN-γ), and interleukine (IL)-6 are two of the most potent activators of the JAK/STAT pathway, and it was shown to be elevated in PD. Stimulation of microglial cell with aggregated α-SYN results in production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and IL-1β in PD. Dysregulation of the JAK/STAT in PD and its involvement in various inflammatory pathways make it a promising PD therapy approach. So far, a variety of synthetic or natural small-molecule JAK inhibitors (Jakinibs) have been found promising in managing a spectrum of ailments, many of which are in preclinical research or clinical trials. Herein, we provided a perspective on the function of the JAK/STAT signaling pathway in PD progression and gathered data that describe the rationale evidence on the potential application of Jakinibs to improve neuroinflammation in PD.

The Protective Effects of α-Mangostin Attenuate Sodium Iodate-Induced Cytotoxicity and Oxidative Injury via Mediating SIRT-3 Inactivation via the PI3K/AKT/PGC-1α Pathway

It is well known that age-related macular degeneration (AMD) is an irreversible neurodegenerative disease that can cause blindness in the elderly. Oxidative stress-induced retinal pigment epithelial (RPE) cell damage is a part of the pathogenesis of AMD. In this study, we evaluated the protective effect and mechanisms of alpha-mangostin (α-mangostin, α-MG) against NaIO3-induced reactive oxygen species (ROS)-dependent toxicity, which activates apoptosis in vivo and in vitro. MTT assay and flow cytometry demonstrated that the pretreatment of ARPE-19 cells with α-MG (0, 3.75, 7.5, and 15 μM) significantly increased cell viability and reduced apoptosis from NaIO3-induced oxidative stress in a concentration-dependent manner, which was achieved by the inhibition of Bax, cleaved PARP-1, cleaved caspase-3 protein expression, and enhancement of Bcl-2 protein. Furthermore, pre-incubation of ARPE-19 cells with α-MG markedly inhibited the intracellular ROS and extracellular H2O2 generation via blocking of the abnormal enzyme activities of superoxide dismutase (SOD), the downregulated levels of catalase (CAT), and the endogenous antioxidant, glutathione (GSH), which were regulated by decreasing PI3K-AKT-PGC-1α-STRT-3 signaling in ARPE-19 cells. In addition, our in vivo results indicated that α-MG improved retinal deformation and increased the thickness of both the outer nuclear layer and inner nuclear layer by inhibiting the expression of cleaved caspase-3 protein. Taken together, our results suggest that α-MG effectively protects human ARPE-19 cells from NaIO3-induced oxidative damage via antiapoptotic and antioxidant effects.

Improving Anti-Inflammatory Effect of Luteolin with Nano-Micelles in the Bacteria-Induced Lung Infection

The effective therapy for lung infectious diseases became more and more difficult since the severe antibiotic resistance of pathogenic microorganisms, it is urgent to develop new antimicrobial agents. Luteolin has been reported to play a crucial part in host immune responses. However, the clinical use of luteolin is impeded due to its hydrophobicity and low oral bioavailability. In this study, we formulated luteolin-loaded Methoxy poly(ethylene glycol)-poly(lactide) micelles (luteolin/MPEG-PLA), to improve the bioavailability of luteolin in lung infectious diseases. The results showed that luteolin/MPEG-PLA treatment could reduce the adhesion of Klebsiella pneumoniae (K. pneumoniae) to lung epithelial cells and enhance the germicidal ability of macrophages against K. pneumoniae compared to untreated group. Meanwhile, luteolin/MPEG-PLA showed stronger adhesion resistance of epithelial cells and germicidal ability of macrophages compared with free luteolin. In vivo study, luteolin/MPEG-PLA administration significantly promoted the clearance of bacteria and reduced inflammatory infiltration of lung tissue in K. pneumoniae induced lung infectious mice model. Further studies showed that treatment with luteolin/MPEG-PLA reduced the mRNA expression of LPS-induced inflammatory cytokines and chemokines in macrophages significantly. In general, luteolin/MPEG-PLA can enhance the anti-bacterial ability of lung epithelial cells and macrophages, and has a stronger therapeutic effect than free luteolin in bacterial-induced lung infection. Luteolin/MPEG-PLA may be an excellent potential drug for bacterial-induced lung infectious diseases treatment.

Safety and bioactivity assessment of aqueous extract of Thai Henna (Lawsonia inermis Linn.) Leaf

The worldwide demand for a natural dye by the cosmetic and food industry has recently gained interest. To provide scientific data supporting the usage of Thai henna leaf as a natural colorant, the phytochemical constituents, safety, and bioactivity of aqueous extract of the henna leaf by autoclave (HAE) and hot water (HHE) were determined. HAE contained a higher amount of total phenolic and flavonoid contents than HHE. The major constituents in both extracts were ferulic acid, gallic acid, and luteolin. The extracts displayed no marked mutagenic activity both in vitro and in vivo mammalian-like biotransformation. HAE and HHE also exhibited non-cytotoxicity to human immortalized keratinocyte cells (HaCaT), peripheral blood mononuclear cells (PBMCs), and murine macrophage RAW 264.7 cell line with IC₂₀ and IC₅₀ > 200 μg/ml. The extracts exhibited antioxidant and anti-inflammatory activity as evidenced by significant scavenging of ABTS and DPPH radicals and decreasing NO levels in LPS-induced RAW 264.7 cells. The antioxidant and anti-inflammatory properties of the extracts might be attributed to their phenolic and flavonoid contents. In conclusion, the traditional use of henna as a natural dye appears not to exert toxic effects and seems biosecure. Regarding safety, antioxidant, and anti-inflammatory properties, the aqueous extract of Thai henna leaf might thus serve as a readily available source for utilization in commercial health industries.

Bioactive and Nutritional Potential of Medicinal and Aromatic Plant (MAP) Seasoning Mixtures

Medicinal and aromatic plants (MAPs), worldwide appreciated and used as condiments, dyes, and preservatives, possess several biological properties that justify their continuous application in the food industry. In the present study, the nutritional and chemical profiles, as well as the bioactive properties of four combinations of condiments, sold for seasoning poultry, meat, fish, and salads, were evaluated. Twenty-five phenolic compounds (HPLC-DAD-ESI/MS) were identified, with apigenin-O-malonyl-pentoside-hexoside as the major compound detected in all extracts. Oxalic and citric acids were identified in all mixtures (UFLC-PDA), as well as all the four tocopherol isoforms (HPLC-fluorescence). Regarding bioactivities, the mixtures for meat and salads (TBARS) and meat and poultry (OxHLIA) stood out for their antioxidant potential, whereas for the anti-inflammatory and antitumor properties, the mixtures revealing the greatest results were those for poultry and salad, respectively. In terms of antimicrobial activity, all the mixtures revealed the capacity to inhibit the growth of some bacterial strains. In brief, condiment mixtures showed to be a good source of bioactive compounds, as they confer health benefits, validating the importance of their inclusion in the human diet as a good dietary practice.

Anti-Inflammatory and Proliferative Properties of Luteolin-7-O-Glucoside

Flavonoids display a broad range of structures and are responsible for the major organoleptic characteristics of plant-derived foods and beverages. Recent data showed their activity, and in particular of luteolin-7-O-glucoside (LUT-7G), in reduction of oxidative stress and inflammatory mechanisms in different physiological systems. In this paper, we tried to elucidate how LUT-7G could exert both antioxidant and anti-inflammatory effects in endothelial cells cultured in vitro. Here, we showed that LUT-7G is able to inhibit the STAT3 pathway, to have an antiproliferative action, and an important antioxidant property in HUVEC cells. These properties are exerted by the flavone in endothelial through the transcriptional repression of a number of inflammatory cytokines and their receptors, and by the inhibition of ROS generation. ROS and STAT3 activation has been correlated with the production of oxysterols and other hydroxylated fatty acids, and they have been recognized important as players of atherogenesis and cardiocirculatory system diseases. The analysis of the general production pathway of these hydroxylated species, showed a strong decrease of cholesterol hydroxylated species such as 7-alpha-hydroxicholesterol, 7-beta-hydroxicholesterol by the treatment with LUT-7G. This confirms the anti-inflammatory properties of LUT-7G also in the endothelial district, showing for the first time the molecular pathway that verify previous postulated cardiovascular benefits of this flavone.

Anti-inflammatory effects of Flos Lonicerae Japonicae Water Extract are regulated by the STAT/NF-κB pathway and HO-1 expression in Virus-infected RAW264.7 cells

This study examined the effect of the Flos Lonicerae Japonicae water extract (FLJWE), chlorogenic acid, and luteolin on pseudorabies virus (PRV)-induced inflammation in RAW264.7 cells and elucidated related molecular mechanisms. The results revealed that FLJWE and luteolin, but not chlorogenic acid, inhibited the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and inflammatory cytokines in PRV-infected RAW 264.7 cells. We found that the FLJWE and luteolin suppressed nuclear factor (NF)-κB activation by inhibiting the phosphorylation of signal transducer and activator of transcription 1 and 3 (STAT1 and STAT3, respectively). Moreover, the FLJWE significantly upregulated the expression of pNrf2 and its downstream target gene heme oxygenase-1 (HO-1). Our data indicated that FLJWE and luteolin reduced the expression of proinflammatory mediators and inflammatory cytokines, such as COX-2 and iNOS, through the suppression of the JAK/STAT1/3-dependent NF-κB pathway and the induction of HO-1 expression in PRV-infected RAW264.7 cells. The findings indicate that the FLJWE can be used as a potential antiviral agent.

Luteolin Potentially Treating Prostate Cancer and COVID-19 Analyzed by the Bioinformatics Approach: Clinical Findings and Drug Targets

Coronavirus disease 2019 (COVID-19) is a serious epidemic, characterized by potential mutation and can bring about poor vaccine efficiency. It is evidenced that patients with malignancies, including prostate cancer (PC), may be highly vulnerable to the SARS-CoV-2 infection. Currently, there are no existing drugs that can cure PC and COVID-19. Luteolin can potentially be employed for COVID-19 treatment and serve as a potent anticancer agent. Our present study was conducted to discover the possible drug target and curative mechanism of luteolin to serve as treatment for PC and COVID-19. The differential gene expression of PC cases was determined via RNA sequencing. The application of network pharmacology and molecular docking aimed to exhibit the drug targets and pharmacological mechanisms of luteolin. In this study, we found the top 20 up- and downregulated gene expressions in PC patients. Enrichment data demonstrated anti-inflammatory effects, where improvement of metabolism and enhancement of immunity were the main functions and mechanism of luteolin in treating PC and COVID-19, characterized by associated signaling pathways. Additional core drug targets, including MPO and FOS genes, were computationally identified accordingly. In conclusion, luteolin may be a promising treatment for PC and COVID-19 based on bioinformatics findings, prior to future clinical validation and application.

Ethyl acetate fraction of flavonoids from Polygonum hydropiper L. modulates pseudorabies virus-induced inflammation in RAW264.7 cells via the nuclear factor-kappa B and mitogen-activated protein kinase pathways

Pseudorabies virus (PRV) infection leads to severe inflammatory responses and tissue damage, and many natural herbs exhibit protective effects against viral infection by modulating the inflammatory response. An ethyl acetate fraction of flavonoids from Polygonum hydropiper L. (FEA) was prepared through ethanol extraction and ethyl acetate fractional extraction. An inflammatory model was established in RAW264.7 cells with PRV infection to evaluate the anti-inflammatory activity of FEA by measuring cell viability, nitric oxide (NO) production, reactive oxygen species (ROS) release, and mRNA expression of inflammatory factors, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Its functional mechanism was investigated by analyzing the phosphorylation and nuclear translocation of key proteins in the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Our findings indicate that PRV induced inflammatory responses in RAW264.7 cells, and the responses were similar to that in lipopolysaccharide (LPS)-stimulated cells. FEA significantly suppressed NO synthesis and down-regulated both expression and secretion of COX-2, iNOS, and inflammatory cytokines (P<0.05 or P<0.01). FEA also reduced NF-κB p65 translocation into the nucleus and decreased MAPK phosphorylation, indicating that the NF-κB/MAPK signaling pathway may be closely related to the inflammatory response during viral infection. The findings suggested the potential pharmaceutical application of FEA as a natural product that can treat viral infections due to its ability to mitigate inflammatory responses.

Natural Antioxidant and Anti-Inflammatory Compounds in Foodstuff or Medicinal Herbs Inducing Heme Oxygenase-1 Expression

Heme oxygenase-1 (HO-1) is an inducible antioxidant enzyme that catalyzes heme group degradation. Decreased level of HO-1 is correlated with disease progression, and HO-1 induction suppresses development of metabolic and neurological disorders. Natural compounds with antioxidant activities have emerged as a rich source of HO-1 inducers with marginal toxicity. Here we discuss the therapeutic role of HO-1 in obesity, hypertension, atherosclerosis, Parkinson's disease and hepatic fibrosis, and present important signaling pathway components that lead to HO-1 expression. We provide an updated, comprehensive list of natural HO-1 inducers in foodstuff and medicinal herbs categorized by their chemical structures. Based on the continued research in HO-1 signaling pathways and rapid development of their natural inducers, HO-1 may serve as a preventive and therapeutic target for metabolic and neurological disorders.

Luteolin inhibits respiratory syncytial virus replication by regulating the MiR-155/SOCS1/STAT1 signaling pathway

Background

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection in infants, children, immunocompromised adults, and elderly individuals. Currently, there are few therapeutic options available to prevent RSV infection. The present study aimed to investigate the effects of luteolin on RSV replication and the related mechanisms.

Material and methods

We pretreated cells and mice with luteolin before infection with RSV, the virus titer, expressions of RSV-F, interferon (IFN)-stimulated genes (ISGs), and production of IFN-α and IFN-β were determined by plaque assay, RT-qPCR, and ELISA, respectively. The activation of Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) signaling pathway was detected by Western blotting and luciferase assay. Proteins which negatively regulate STAT1 were determined by Western blotting. Then cells were transfected with suppressor of cytokine signaling 1 (SOCS1) plasmid and virus replication and ISGs expression were determined. Luciferase reporter assay and Western blotting were performed to detect the relationship between SOCS1 and miR-155.

Results

Luteolin inhibited RSV replication, as shown by the decreased viral titer and RSV-F mRNA expression both in vitro and in vivo. The antiviral activity of luteolin was attributed to the enhanced phosphorylation of STAT1, resulting in the increased production of ISGs. Further study showed that SOCS1 was downregulated by luteolin and SOCS1 is a direct target of microRNA-155 (miR-155). Inhibition of miR-155 rescued luteolin-mediated SOCS1 downregulation, whereas upregulation of miR-155 enhanced the inhibitory effect of luteolin.

Conclusion

Luteolin inhibits RSV replication by regulating the miR-155/SOCS1/STAT1 signaling pathway.

Mechanism investigation on Bisphenol S-induced oxidative stress and inflammation in murine RAW264.7 cells: The role of NLRP3 inflammasome, TLR4, Nrf2 and MAPK

Bisphenol S is considered as a safer alternative to bisphenol A. In the present study, we used murine macrophages to investigate the effects of BPS exposure on oxidative stress and inflammatory response as well as the underlying mechanism. Cells were exposed to BPS at various concentrations for short period of times. Results showed that 10^-8 M BPS triggered oxidative stress by increasing ROS/RNS production, increased the levels of oxidant enzyme NOX1/2, and decreased the levels of antioxidant enzymes SOD1/2, CAT and GSH-Px. 10^-8 M BPS exposure significantly induced the production of proinflammatory mediators. Activation of the NLRP3 inflammasome, TLR4, and MAPK pathways was involved in this process. Furthermore, we illustrated that NAC pretreatment diminished these effects triggered by BPS exposure. Collectively, our data suggested that BPS at a dose relevant to human serum concentration induced oxidative stress and inflammatory response in macrophages. These novel findings shed light on the concerns regarding the potential adverse effects of BPS exposure that requires further careful attention.

Toxic Effects of Urethane Dimethacrylate on Macrophages Through Caspase Activation, Mitochondrial Dysfunction, and Reactive Oxygen Species Generation

Urethane dimethacrylate (UDMA) is a dimethacrylate-based resin monomer that can react with other related monomers and inorganic particles, causing hydrophobic polymerization through cross-linking upon light activation. UDMA polymers are commonly used for the reconstruction and reinforcement of teeth and bones. UDMA can become unbound and be released from light-cured polymer resins. Thus far, no evidence exists on the toxic effects of UDMA and its related working mechanisms for macrophages. Therefore, in the present study, we investigated the cytotoxicity, mode of cell death, DNA damage, caspase activities, mitochondrial dysfunction, and reactive oxygen species (ROS) generation in RAW264.7 macrophages treated with UDMA using the lactate dehydrogenase (LDH) assay kit, Annexin V-FITC and PI assays, micronucleus formation and comet assay, caspase fluorometric assay, JC-1 assay, and 2ʹ,7ʹ-dichlorofluorescin diacetate (DCFH-DA) assay, respectively. Our results show that UDMA induced cytotoxicity; apoptosis and necrosis; genotoxicity, which is also called DNA damage; increased caspase-3, -8, and -9 activities; mitochondrial dysfunction; and intracellular ROS generation in a concentration-dependent manner in RAW264.7 macrophages. Thus, based on the observed inhibited concentration parallel trends, we concluded that UDMA induces toxic effects in macrophages. Furthermore, UDMA-induced intracellular ROS generation, cytotoxicity, and DNA damage were reduced by N-acetyl-L-cysteine.

Anti-Inflammatory and Anti-Oxidative Effects of luteolin-7-O-glucuronide in LPS-Stimulated Murine Macrophages through TAK1 Inhibition and Nrf2 Activation

Various herbal extracts containing luteolin-7-O-glucuronide (L7Gn) have been traditionally used to treat inflammatory diseases. However, systemic studies aimed at elucidating the anti-inflammatory and anti-oxidative mechanisms of L7Gn in macrophages are insufficient. Herein, the anti-inflammatory and anti-oxidative effects of L7Gn and their underlying mechanisms of action in macrophages were explored. L7Gn inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages by transcriptional regulation of inducible NO synthase (iNOS) in a dose-dependent manner. The mRNA expression of inflammatory mediators, including cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α), was inhibited by L7Gn treatment. This suppression was mediated through transforming growth factor beta-activated kinase 1 (TAK1) inhibition that leads to reduced activation of nuclear factor-κB (NF-κB), p38, and c-Jun N-terminal kinase (JNK). L7Gn also enhanced the radical scavenging effect and increased the expression of anti-oxidative regulators, including heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and NAD(P)H quinone oxidoreductase 1 (NQO1), by nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) activation. These results indicate that L7Gn exhibits anti-inflammatory and anti-oxidative properties in LPS-stimulated murine macrophages, suggesting that L7Gn may be a suitable candidate to treat severe inflammation and oxidative stress.

Development of a novel nitric oxide (NO) production inhibitor with potential therapeutic effect on chronic inflammation

Inflammation is a complex biological response to stimuli. Activated macrophages induced excessively release of pro-inflammatory cytokines and mediators such as endogenous radical nitric oxide (NO) play a significant role in the progression of multiple inflammatory diseases. Both natural and synthetic chalcones possess a wide range of bioactivities. In this work, thirty-nine chalcones and three related compounds, including several novel ones, based on bioactive kava chalcones were designed, synthesized and their inhibitory effects on NO production in RAW 264.7 cells were evaluated. The novel compound (E)-1-(2'-hydroxy-4',6'-dimethoxyphenyl)-3-(3-methoxy-4-(3-morpholinopropoxy)phenyl)prop-2-en-1-one (53) exhibited a better inhibitory activity (84.0%) on NO production at 10 μM (IC₅₀ = 6.4 μM) with the lowest cytotoxicity (IC₅₀ > 80 μM) among the tested compounds. Besides, western blot analysis indicated that compound 53 was a potent down-regulator of inducible nitric oxide synthase (iNOS) protein. Docking study revealed that compound 53 also can dock into the active site of iNOS. Furthermore, at the dose of 10 mg/kg/day, compound 53 could both significantly suppress the progression of inflammation on collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) models. In addition, the structure-activity relationship (SAR) of the kava chalcones based analogs was also depicted.

The regulatory effect of flavonoids extracted from Abutilon theophrasti leaves on gene expression in LPS-induced ALI mice via the NF-κB and MAPK signaling pathways

Context: ALI is a common disease characterized by acute pulmonary inflammatory disorder. Abutilon theophrasti Medik. (Malvaceae), as a Chinese traditional medicine, is used for the treatment of inflammation. Its main constituents are flavonoid compounds. Objective: This study investigates the regulatory effect of a TFE from Abutilon theophrasti leaves on gene expression in LPS-induced ALI mice via the NF-κB and MAPK signaling pathways. Materials and methods: Kunming mice were intragastrically administered TFE (0.25, 0.5, 1.0 g/kg) for 5 days, and then ALI was induced via intranasal administration 40 μg of LPS in 10 μL PBS after intragastric administration on the 5th day, and PBS and DEX (2 mg/kg) were negative and positive control groups, respectively. Results: The relative expression of iNOS gene was 0.707, 0.507 and 0.483 for 0.25, 0.5 and 1.0 g/kg TFE, and COX-2 gene expression was also reduced after treatment by three concentrations of TFE with 0.768, 0.545, and 0.478. The mRNA expression levels of p65 were 0.61, 0.43 and 0.27 for 0.25, 0.5 and 1.0 g/kg TFE and IκB levels were increased in a dose-dependent manner with 3.99, 13.69 and 34.36. 0.5 and 1.0 g/kg TFE inhibited the expression of ERK1/2 with 0.59 and 0.38, p38MAPK with 0.62 and 0.54, and JNK with 0.37 and 0.29, and JNK mRNA expression was 0.60 for 0.25 g/kg TFE. Discussion and conclusion: These results indicate that the regulatory mechanisms of TFE on gene expression in LPS-induced ALI mice include inhibition of the NF-κB and MAPK signaling pathways.

Suppression of Src and Syk in the NF-κB signaling pathway by Olea europaea methanol extract is leading to its anti-inflammatory effects

ETHNOPHARMACOLOGICAL RELEVANCE

Olea europaea L., (Oleaceae) has been used widely in folk medicine in the European Mediterranean islands, India, Asia, and other parts of the world. Although this plant has high ethnopharmacological value for treating inflammatory diseases, the molecular mechanisms of how it inhibits the inflammatory response are not fully understood. In this study, we sought to identify the anti-inflammatory mechanisms of this plant.

MATERIALS AND METHODS

Using macrophages, we investigated the effects of O. europaea L. methanol extract (Oe-ME) and ethanol extract (Oe-EE) on the production of inflammatory mediator nitric oxide (NO) and prostaglandin E₂ (PGE₂), the expression levels of pro-inflammatory genes and intracellular inflammatory signaling activities.

RESULTS

Oe-ME and Oe-EE suppressed the production of NO in lipopolysaccharide-(LPS-), Pam3CSK4-, and poly (I:C)-stimulated RAW264.7 cells; importantly, no cytotoxicity was observed. Oe-ME and Oe-EE reduced production of PGE₂ without exhibiting cytotoxicity. The mRNA expression levels of cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS), IL-6, IL-1β, and tumor necrosis factor (TNF)-α were down-regulated by Oe-ME and Oe-EE. Nuclear fraction and whole lysate immunoblotting analyses and overexpression experiments strongly suggested that Oe-ME decreased the translocation of p65 and p50 (nuclear factors of the NF-κB subunit) as well as Src and Syk.

CONCLUSION

These results suggest that Oe-ME exerts its anti-inflammatory effects by targeting Src and Syk in the NF-κB signaling pathway.