Protective effects of diketopiperazines from Moslae Herba against influenza A virus-induced pulmonary inflammation via inhibition of viral replication and platelets aggregation

The high-throughput solid-phase extraction of cis-cyclo(L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) from Lactobacillus plantarum demonstrates efficacy against multidrug-resistant bacteria and influenza A (H3N2) virus

Introduction: 2,5-diketopiperazines are the simplest forms of cyclic dipeptides (CDPs) and have diverse frameworks with chiral side chains that are useful for drug development. Previous research has investigated the antimicrobial properties of proline-linked CDPs and their combinations in the culture filtrate (CF) of Lactobacillus plantarum LBP-K10 using anion exchange chromatography (AEC). However, the quantity of CDPs showcasing notable anti-influenza virus activity derived from AECs was generally lower than those originating from Lactobacillus CF. Methods: To address this issue, the study aims to propose a more efficient method for isolating CDPs and to introduce the antiviral combinations of CDPs obtained using a new method. The study employed a novel technique entailing high-throughput C18-based solid-phase extraction with a methanol gradient (MeSPE). The MeSPE method involved increasing the methanol concentration from 5% to 50% in 5% increments. Results: The methanol SPE fractions (MeSPEfs) eluted with methanol concentrations between 35% and 45% evinced substantial efficacy in inhibiting the influenza A/H3N2 virus via plaque-forming assay. MeSPEf-45, the 45% MeSPEf, exhibited exceptional efficacy in preventing viral infections in Madin-Darby kidney cells, surpassing both individual CDPs and the entire set of MeSPEfs. To identify the specific antiviral components of MeSPEf-45, all MeSPEfs were further fractionated through preparative high-performance liquid chromatography (prep-HPLC). MeSPEf-45 fractions S8 and S11 presented the highest activity against multidrug-resistant bacteria and influenza A/H3N2 virus among all MeSPEfs, with 11 common fractions. Antiviral fractions S8 and S11 were identified as proline-based CDPs, specifically cis-cyclo(L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro), using gas chromatography-mass spectrometry. The combination of MeSPEf-45 fractions S8 and S11 displayed superior antibacterial and anti-influenza virus effects compared to the individual fractions S8 and S11. Discussion: High-throughput MeSPE-derived MeSPEfs and subsequent HPLC-fractionated fractions presents an innovative approach to selectively purify large amounts of potent antimicrobial CDPs from bacterial CF. The findings also show the effectiveness of physiologically bioactive combinations that utilize fractions not containing CDP. This study provides the initial evidence demonstrating the antimicrobial properties of CDPs acquired through high-throughput SPE techniques.

Importance of quorum sensing crosstalk in the brown alga Saccharina latissima epimicrobiome

Brown macroalgae are colonized by diverse microorganisms influencing the physiology of their host. However, cell-cell interactions within the surface microbiome (epimicrobiome) are largely unexplored, despite the significance of specific chemical mediators in maintaining host-microbiome homeostasis. In this study, by combining liquid chromatography coupled to mass spectrometry (LC-MS) analysis and bioassays, we demonstrated that the widely diverse fungal epimicrobiota of the brown alga Saccharina latissima can affect quorum sensing (QS), a type of cell-cell interaction, as well as bacterial biofilm formation. We also showed the ability of the bacterial epimicrobiota to form and inhibit biofilm growth, as well as to activate or inhibit QS pathways. Overall, we demonstrate that QS and anti-QS compounds produced by the epimicrobiota are key metabolites in these brown algal epimicrobiota communities and highlight the importance of exploring this epimicrobiome for the discovery of new bioactive compounds, including potentially anti-QS molecules with antifouling properties.

Influenza A (H1N1) virus induced long-term remission in a refractory acute myeloid leukaemia

There have been reports of haematological cancer patients achieving spontaneous remission after being infected with the influenza A or SARS-COV-2 virus. Here, we present the first case of long-term complete remission (CR) induced by influenza A (IAV, H1N1 subtype) in a refractory AML patient and have functionally validated this finding in two different animal disease models. We observed a significant increase in the proportion of helper T cells in the patient after IAV infection. The levels of cytokines, including IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ and TNF-α, were higher in IAV-infected patients compared with control groups. These findings indicate that the anti-tumour effects induced by IAV are closely related to the modification of the immune response. Our study provides new evidence of the anti-tumour effects of IAV from a clinical practice perspective.

Inhibitory Effects and Related Molecular Mechanisms of Huanglian-Ganjiang Combination Against H1N1 Influenza Virus

Influenza is an infectious acute respiratory disease with complications and a high mortality rate; the effective medicines for influenza therapy are limited. "Huanglian" or Coptidis Rhizoma, Coptis chinensis Franch., Ranunculaceae, and "ganjiang" or Zingiberis Rhizoma, Zingiber officinale Roscoe, Zingiberaceae, combination is clinically used for treating respiratory diseases. HPLC was applied for the quantification of berberine hydrochloride (1.101 mg/ml) and 6-gingerol (38.41 μg/ml) in the H₂O-soluble extract of the herbal formulation. In this study, the effect of "huanglian"- "ganjiang" extract on influenza virus H1N1-induced acute pulmonary inflammation was evaluated, in addition to the investigation of its anti-influenza mechanism in a mouse model. The analyzed herbal combination inhibited the expression of cytokine IL-6 and stimulated the expression of IL-2 in the serum of influenza virus-infected mice. Meanwhile, the herbal combination downregulated the gene and protein expression levels of TLR3, TLR7, MyD88, RIG-I, MAVS, TRAF3, and NF-κB p65, which are key targets of toll-like and RIG-I-like receptor signaling pathways in mice. In addition, the herbal combination could also promote the combination of intracellular autophagosomes and lysosomes in autophagosome-lysosome formation and improve impaired fusion of autophagosomes and lysosomes by influenza virus. This study suggested that the "huanglian"- "ganjiang" extract may be a candidate therapeutic strategy for the treatment of H1N1 influenza.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-023-00372-z.

Lignans from Mosla scabra Ameliorated Influenza A Virus-Induced Pneumonia via Inhibiting Macrophage Activation

The lower respiratory tract infection, induced by influenza virus, coronaviruses, and respiratory syncytial virus, remains a serious threat to human health that can cause a global pandemic. Thus, finding effective chemicals and therapeutic measures to advance the functional restoration of the respiratory tract after infection has been the emphasis of the studies on the subjects. Mosla scabra is a natural medicinal plant used for treating various lung and gastrointestinal diseases, including viral infection, cough, chronic obstructive pulmonary disease, acute gastroenteritis, and diarrhoea. In this study, the antiviral and anti-inflammatory effects of total lignans (MSTL) extracted from the plant were investigated in influenza A virus (IAV)-infected mice and RAW 264.7 macrophages. MSTL could not only protect the macrophages against IAV-induced pyroptosis but also could lighten the lung inflammation induced by IAV in vivo and in vitro. The network pharmacology analysis revealed that differentially expressed genes, mainly involving in EGFR tyrosine kinase inhibitor resistance, endocrine resistance, HIF-1 signaling pathway, C-type lectin receptor signaling pathway, and FOXO signaling pathway, contributed to the IAV-induced alveolar macrophage dysfunction. It indicated that MSTL enhanced the function of alveolar macrophages and improved IAV-induced lung injury in mice.

Anti-Inflammatory Mechanisms of Total Flavonoids from Mosla scabra against Influenza A Virus-Induced Pneumonia by Integrating Network Pharmacology and Experimental Verification

Influenza virus is one of the most common infectious pathogens that could cause high morbidity and mortality in humans. However, the occurrence of drug resistance and serious complications extremely complicated the clinic therapy. Mosla scabra is a natural medicinal plant used for treating various lung and gastrointestinal diseases, including viral infection, cough, chronic obstructive pulmonary disease, acute gastroenteritis, and diarrhoea. But the therapeutic effects of this herbal medicine had not been expounded clearly. In this study, a network pharmacology approach was employed to investigate the protective mechanism of total flavonoids from M. scabra (MSTF) against influenza A virus- (IAV-) induced acute lung damage and inflammation. The active compounds of MSTF were analyzed by LC-MS/MS and then evaluated according to their oral bioavailability and drug-likeness index. The potential targets of each active compound in MSTF were identified by using PharmMapper Server, whereas the potential genes involved in IAV infection were obtained from GeneGards. The results showed that luteoloside, apigenin, kaempherol, luteolin, mosloflavone I, and mosloflavone II were the main bioactive compounds found in MSTF. Primarily, 23 genes were identified as the targets of those five active compounds, which contributed to the inactivation of chemical carcinogenesis ROS, lipid and atherosclerosis, MAPK signaling pathway, pathways in cancer, PI3K-AKT signaling pathway, proteoglycans in cancer, and viral carcinogenesis. Finally, the animal experiments validated that MSTF improved IAV-induced acute lung inflammation via inhibiting MAPK, PI3K-AKT, and oxidant stress pathways. Therefore, our study demonstrated the potential inhibition of MSTF on viral pneumonia in mice and provided a strategy to characterize the molecular mechanism of traditional Chinese medicine by a combinative method using network pharmacology and experimental validation.

Platelet-Mediated NET Release Amplifies Coagulopathy and Drives Lung Pathology During Severe Influenza Infection

The influenza A virus (IAV) causes a respiratory tract infection with approximately 10% of the population infected by the virus each year. Severe IAV infection is characterized by excessive inflammation and tissue pathology in the lungs. Platelet and neutrophil recruitment to the lung are involved in the pathogenesis of IAV, but the specific mechanisms involved have not been clarified. Using confocal intravital microscopy in a mouse model of IAV infection, we observed profound neutrophil recruitment, platelet aggregation, neutrophil extracellular trap (NET) production and thrombin activation within the lung microvasculature in vivo. Importantly, deficiency or antagonism of the protease-activated receptor 4 (PAR4) reduced platelet aggregation, NET production, and neutrophil recruitment. Critically, inhibition of thrombin or PAR4 protected mice from virus-induced lung tissue damage and edema. Together, these data imply thrombin-stimulated platelets play a critical role in the activation/recruitment of neutrophils, NET release and directly contribute to IAV pathogenesis in the lung.

Cyclic Dipeptides: The Biological and Structural Landscape with Special Focus on the Anti-Cancer Proline-Based Scaffold

Cyclic dipeptides, also know as diketopiperazines (DKP), the simplest cyclic forms of peptides widespread in nature, are unsurpassed in their structural and bio-functional diversity. DKPs, especially those containing proline, due to their unique features such as, inter alia, extra-rigid conformation, high resistance to enzyme degradation, increased cell permeability, and expandable ability to bind a diverse of targets with better affinity, have emerged in the last years as biologically pre-validated platforms for the drug discovery. Recent advances have revealed their enormous potential in the development of next-generation theranostics, smart delivery systems, and biomaterials. Here, we present an updated review on the biological and structural profile of these appealing biomolecules, with a particular emphasis on those with anticancer properties, since cancers are the main cause of death all over the world. Additionally, we provide a consideration on supramolecular structuring and synthons, based on the proline-based DKP privileged scaffold, for inspiration in the design of compound libraries in search of ideal ligands, innovative self-assembled nanomaterials, and bio-functional architectures.

Pharmacokinetics and Pharmacodynamics of Huanglian-Houpo Decoction Based on Berberine Hydrochloride and Magnolol Against H1N1 Influenza Virus

BACKGROUND AND OBJECTIVES

Huanglian-Houpo decoction (HH), which is recorded in the famous traditional Chinese medicine monograph "Puji Fang," contains two individual herbs, Huanglian (Rhizoma coptidis) and Houpo (Magnoliae officinalis cortex). It was regularly used to treat seasonal epidemic colds and influenzas in ancient China. Our laboratory discovered that HH has a significant anti-H1N1 influenza virus effect. However, no pharmacokinetic and pharmacodynamic data concerning the anti-H1N1 influenza virus activity of HH are available to date. In the current study, the concentration-time profiles of two major components of HH, berberine and magnolol, in rat plasma were investigated.

METHODS

An integrate pharmacokinetic approach was developed for evaluating the holistic pharmacokinetic characteristics of berberine and magnolol from HH. Additionally, the inhibition rate and levels of IFN-β in MDCK cells infected by influenza virus were analyzed. Data were calculated using 3p97 with pharmacokinetic analysis.

RESULTS

The estimated pharmacokinetic parameters were maximum plasma concentration (C_max) 0.9086 μg/ml, area under the concentration-time curve (AUC) 347.74 μg·min/ml, and time to reach C_max (T_max) 64.69 min for berberine and C_max = 0.9843 μg/ml, AUC= 450.64 μg·min/ml, T_max = 56.86 min for magnolol, respectively. Furthermore, integrated pharmacokinetic and pharmacodynamic analysis showed that the highest plasma concentration, inhibition rate and interferon-β (IFN-β) secretion of HH first increased and then weakened over time, reaching their peaks at 60 min. The plasma concentration of HH is directly related to the anti-influenza virus effect.

CONCLUSION

The results indicated that berberine and magnolol are the main active ingredients of HH related to its anti-influenza virus effect, which is related to the improvement of IFN-β secretion.

Phytochemical Profiles and their Anti-inflammatory Responses Against Influenza from Traditional Chinese Medicine or Herbs

Traditional Chinese medicine (TCM) or herbs are widely used in the prevention and treatment of viral infectious diseases. However, the underlying mechanisms of TCMs remain largely obscure due to complicated material basis and multi-target therapeutics. TCMs have been reported to display anti-influenza activity associated with immunoregulatory mechanisms by enhancing host antiinfluenza immune responses. Previous studies have helped us understand the direct harm caused by the virus itself. In this review, we have tried to summarize recent progress in TCM-based anti-influenza research on the indirect harmful immune responses caused by influenza viruses. In particular, the phytochemicals from TCMs responsible for molecular mechanisms of action belonging to different classes, including phenolic compounds, flavonoids, alkaloids and polysaccharides, have been identified and demonstrated. In addition, this review focuses on the pharmacological mechanism, e.g., inflammatory responses and the interferon (IFN) signaling pathway, which can provide a theoretical basis and approaches for TCM based anti-influenza treatment.

Shenling Baizhu Powder Inhibits RV-SA11-Induced Inflammation and Rotavirus Enteritis via TLR4/MyD88/NF-κB Signaling Pathway

Rotavirus enteritis (RVE) is a common acute intestinal infectious disease caused by rotavirus infection. It is an important cause of death in children younger than 5 years worldwide. Shenling baizhu powder (SBP), a classic traditional Chinese formulation, is one of the most popularly prescribed medicines for digestive diseases. Clinical studies have revealed the protective effects of SBP on RVE. However, the potential mechanism is still unclear. In this study, we aimed to evaluate the anti-rotavirus effect of SBP and its mechanism, focusing on the TLR4/MyD88/NF-κB signaling pathway. Our results demonstrated that, based on the inhibition of the virus-induced cytopathic effect in Caco-2 cells, the concentration for 50% of maximal effect (EC50) and selectivity index (SI) of SBP for RV-SA11 in the serum were 5.911% and 11.63, respectively. A total of 219 active compounds with oral bioavailability ≥30% and drug-likeness ≥ 0.18 were selected from the 10 ingredients present in the formulation of SBP, which acted on 471 potential targets. A total of 226 target genes of RVE were obtained from the GeneCards database. The protein-protein interaction (PPI) network showed that there was a close interaction between 44 common targets of SBP and RVE. The results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that SBP acted on RVE through various inflammatory pathways and the intestinal immune network. Subsequently, we investigated the effect of SBP on TLR4/MyD88/NF-κB signaling pathway in vitro. After infection with RV- SA11, the expression of TLR4, MyD88, and NF-κB mRNA and protein increased significantly, which could be abolished by SBP treatment. In addition, the IL-1β, TNF-α, IL-6, and IFN-β levels increased markedly in Caco-2 cells infected with RV-SV11. Treatment with SBP partly reversed the changes of IL-1β, TNF-α, and IL-6, while further increased the level of IFN-β. In conclusion, our study revealed that SBP can significantly inhibit rotavirus replication and proliferation in vitro. The antiviral effect may be related to the regulation of the TLR4/MyD88/NF-κB signaling pathway, followed by the down regulation of inflammatory cytokines and up regulation of IFN-β induced by rotavirus.

Huanglian-Houpo drug combination ameliorates H1N1-induced mouse pneumonia via cytokines, antioxidant factors and TLR/MyD88/NF-κB signaling pathways

Huanglian-Houpo drug combination (HHDC) is a classical traditional Chinese medicine that has been effectively used to treat seasonal colds and flu. However, no systematic studies of the effects of HHDC on H1N1 influenza infection and the associated mechanisms have been reported. The aim of the present study was to determine the anti-H1N1 influenza effects of HHDC and explore the underlying mechanisms. A mouse model of H1N1-induced pneumonia was established and the mice were treated with HHDC (4, 8 and 16 g/kg) for 5 days after viral challenge. The antiviral effects of HHDC and the underlying mechanisms in the mice were investigated and evaluated with respect to inflammation, oxidative stress and Toll-like receptor (TLR)/myeloid differentiation factor (MyD88)/nuclear factor (NF)-κB signaling pathways. HHDC provided significant protection against weight loss and reduced the H1N1 viral load in the lungs. In addition, HHDC significantly decreased the lung index and increased the spleen and thymus indices of the H1N1-infected mice. HHDC also significantly ameliorated the histopathological changes of pneumonia, decreased serum levels of the cytokines interleukin (IL)-6, tumor necrosis factor-α and interferon-γ, and increased the serum level of IL-2. Moreover, HHDC significantly increased the levels of the antioxidant factors superoxide dismutase and glutathione, and reduced the serum level of nitric oxide. Furthermore, the mRNA and protein expression levels of TLR3, TLR7, MyD88, NF-κB p65 and tumor necrosis factor receptor-associated factor 3 in the lung tissues were significantly decreased by HHDC. These findings suggest that HHDC directly inhibited H1N1 infection in vivo and exerted a therapeutic effect on influenza-induced pneumonia in mice by modulating cytokines, antioxidant factors and TLR/MyD88/NF-κB signaling pathways.

Isofraxidin ameliorated influenza viral inflammation in rodents via inhibiting platelet aggregation

Platelets have been proved to exacerbate influenza infection and its complications. Inhibition of platelet activation may be a feasible method for preventing severe infection and secondary acute lung injury (ALI). Isofraxidin (IFD) is a natural coumarin isolated from the plants Sarcandra glabra and Siberian ginseng, and exerts anticancer, antioxidant and antiinflammatory effects. In the present study, we examined the therapeutic effects of IFD in ADP- or arachidonic acid (AA)-induced platelet aggregation model and in influenza A virus (IAV)-induced ALI mouse model. The results showed that IFD significantly inhibited platelet aggregation induced by ADP and AA in vitro in a concentration-dependent manner as well as the release of soluble P-selectin and platelet factor 4. Moreover, IFD significantly relieved IAV-induced lung inflammation, reduced the expressions of platelet activation biomarkers (P-selectin and CD61), decreased the serum levels of TNF-α, IL-1β, IL-6 and MIP-2, suppressed peripheral platelet aggregation and prolonged the survival time of infected mice. The western blotting results also demonstrated that IFD reduced the phosphorylation levels of PI3K, AKT and p38 in the activated platelets stimulated by ADP and IAV infection. But IFD did not have any effects on IAV replication. It indicated that IFD ameliorated IAV-induced severe lung damage and lethal infection by suppressing platelet aggregation via regulating PI3K/AKT and MAPK pathways.

Can network pharmacology identify the anti-virus and anti- inflammatory activities of Shuanghuanglian oral liquid used in Chinese medicine for respiratory tract infection?

Introduction

Shuanghuanglian (SHL) oral liquid is a well-known traditional Chinese medicine preparation administered for respiratory tract infections in China. However, the underlying pharmacological mechanisms remain unclear. The present study aims to determine the potential pharmacological mechanisms of SHL oral liquid based on network pharmacology.

Methods

A network pharmacology-based strategy including collection and analysis of putative compounds and target genes, network construction, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and Gene Ontology (GO) enrichment, identification of key compounds and target genes, and molecule docking was performed in this study.

Results

A total of 82 bioactive compounds and 226 putative target genes of SHL oral liquid were collected. Of note, 28 hub target genes including 4 major hub target genes: estrogen receptor 1 (ESR1), nuclear receptor coactivator 2 (NCOA2), nuclear receptor coactivator 1 (NCOA1), androgen receptor (AR) and 5 key compounds (quercetin, luteolin, baicalein, kaempferol and wogonin) were identified based on network analysis. The hub target genes mainly enriched in pathways including PI3K-Akt signaling pathway, human cytomegalovirus infection, and human papillomavirus infection, which could be the underlying pharmacological mechanisms of SHL oral liquid for treating diseases. Moreover, the key compounds had great molecule docking binding affinity with the major hub target genes.

Conclusion

Using network pharmacology analysis, SHL oral liquid was found to contain anti-virus, anti-inflammatory, and “multi-compounds and multi-targets” with therapeutic actions. These findings may provide a valuable direction for further clinical application and research.

Moslea Herba flavonoids alleviated influenza A virus-induced pulmonary endothelial barrier disruption via suppressing NOX4/NF-κB/MLCK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Moslae Herba, a common traditional Chinese herb with special flavor, has potential for treating respiratory and gastrointestinal diseases.

AIM OF THIS STUDY

Lung endothelial barrier dysfunction (LEBD) accelerates the pathogenesis of influenza A virus (IAV)-induced secondary acute lung injury. New strategies against LEBD provide benefits in prevention and treatment of IAV. Previous studies showed that flavonoids (MHF), main bioactivity fraction derived from M. Herba, exerted anti-inflammatory and antiviral activities, but the underlying protection of MHF against IAV-induced acute lung injury remained obscure. The present study was to investigate the protection of MHF against IAV-induced LEBD in vivo and in vitro.

MATERIALS AND METHODS

Mice were intranasally challenged with IAV and orally administered with MHF for 5 days. The pulmonary hyperpermeability of infected mice was evaluated by Evans Blue staining and in vivo imaging. Serum levels of inflammatory cytokines and mediators were detected by ELISA assay. The transepithelial electrical resistance (TER) of human pulmonary microvascular endothelial cells (HPMVECs) was measured by using TER meter. The expressions of key proteins in NOX4-mediated NF-κB/MLCK pathways were determined by western blotting.

RESULTS

MHF treatment reduced lung index, W/D ratios, and serum levels of inflammatory factors (IL-6, TNF-α, IL-1β, PLA₂, LBT₄ and ICAM-1) in IAV-infected mice. Evans blue staining and in vivo imaging results revealed that MHF alleviated IAV-induced barrier dysfunction and pulmonary hyperpermeability. Moreover, luteolin and kaempferol, the main activity compounds in MHF, significantly inhibited TNF-α-induced HPMVEC apoptosis, and downregulated NF-κB/MLCK pathway by targeting NOX4.

CONCLUSION

MHF attenuated IAV-induced barrier dysfunction by suppressing NOX4/NF-κB/MLCK pathway and may serve as a potential agent for the prevention of LEBD and IAV.

Liu Shen Wan inhibits influenza a virus and excessive virus-induced inflammatory response via suppression of TLR4/NF-κB signaling pathway in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Liu Shen Wan (LSW), first prescribed in "Lei Yunshang Song Fen Tang Fang", traditional Chinese medicine (TCM), is used to cure influenza, tonsillitis, pharyngitis and mumps for more than one hundred years.

AIM OF STUDY

LSW was proved extensive pharmacological properties, for instance, anti-inflammatory, anticancer, antiviral, analgesic, antibacterial and immunomodulatory activities. Nevertheless, the mechanism of this process and the evaluation of this product is still ambiguous. Hence, the study was designed to investigate the antiviral and anti-inflammatory activities of LSW against the influenza virus in vitro and vivo.

MATERIALS AND METHODS

The antiviral activities of LSW were assayed in virus-infected cells and mice. To study the antiviral effects of LSW against influenza A/PR/8/34 virus (PR8), we employed CPE inhibition assay with different concentrations of LSW at different times of infection in vitro. The mice were intranasally infected with virus to induce viral pneumonia, then treated with different doses of LSW. The death protection of the mice, the lung index, virus titer and pathological changes in the lung tissue of mice were investigated to estimate the anti-virus effect of LSW. Moreover, RT-qPCR was used to determine the mRNA expression of TNF-α, IL-1β, IL-6, and IFN-γ in the A549 cells and the supernatant of lung tissues, and the concentrations of these four cytokines in serum of mice were determined with ELISA. Western blot was used to determine the expression of TLR4, p-NF-κB p65, NF-κB p65, p-IκBα and IκBα in the A549 cells and lung tissues, which are the key targets of TLR4/NF-κB pathway. Moreover, the immunohistochemical assay was used to determine the expression of the NF-κB p65 in the mice lungs.

RESULTS

LSW could significantly inhibit influenza virus at different stages of viral replication (at the process of the pre-, post-, and co-virus infection) in vitro. And LSW (100 mg/kg and 50 mg/kg) could effectively increase the survival time of mice. The virus titres, lung index, pathological changes in the mice lungs also decreased. Moreover, LSW could significantly reduce the contents of IL-1β, TNF-α, IFN-γ and IL-6 in the infected cells and the infected-mice. In addition, LSW could significantly reduce the expression of TLR4, p-NF-κB p65, NF-κB p65 and p-IκBα, while increase the IκBα in the infected cells and in the lung of mice.

CONCLUSIONS

LSW could significantly not only inhibit virus replication and proliferation in vitro, but also ameliorate pneumonia damage in vivo. The antiviral effect was attributed to down-regulating the expression of inflammatory cytokines induced by influenza virus via regulating the activity of TLR4/NF-кB signaling pathway.

Thermally induced cyclization of L -isoleucyl-L -alanine in solid state: Effect of dipeptide structure on reaction temperature and self-assembly

Thermal treatment of short-chain oligopeptides is able to initiate the process of their self-assembly with the formation of organic nanostructures with unique properties. On the other hand, heating can lead to a chemical reaction with the formation of new substances with specific properties and ability to form structures with different morphology. Therefore, in order to have a desired process, researcher needs to find its temperature range. In the present work, cyclization of _L -isoleucyl-_L -alanine dipeptide in the solid state upon heating was studied. Kinetic parameters of this reaction were estimated within the approaches of the nonisothermal kinetics. The correlation between side chain structure of dipeptides and temperature of their cyclization in the solid state was found for the first time. This correlation may be used to predict the temperature, at which dipeptide self-assembly changes to chemical reaction. The differences in self-assembly of linear and cyclic dipeptides were demonstrated using atomic force microscopy. The effect of dipeptide concentration in a source solution and an organic solvent used on self-assembly of dipeptides was shown. The new information obtained on the thermal properties and self-assembly of linear and cyclic forms of _L -isoleucyl-_L -alanine may be useful for the design of new nanomaterials based on oligopeptides, as well as for the synthesis of cyclic oligopeptides.

p-STAT1 regulates the influenza A virus replication and inflammatory response in vitro and vivo

Influenza A virus infection activates various intracellular signaling pathways, which is mediated by the transcription factors. Here, a quantitative phosphoproteomic analysis of A549 cells after infection with influenza A virus (H5N1) was performed and we found that the transcription factor STAT1 was highly activated. Unexpectedly, upon inhibition of p-STAT1, titers of progeny virus and viral protein synthesis were both reduced. The STAT1 inhibitor Fludarabine (FLUD) inhibited an early progeny step in viral infection and reduced the levels of influenza virus genomic RNA (vRNA). Concomitantly, there was reduced expression of inflammatory cytokines in p-STAT1 inhibited cells. In vivo, suppression of p-STAT1 improved the survival of H5N1 virus-infected mice, reduced the pulmonary inflammatory response and viral burden. Thus, our data demonstrated a critical role for p-STAT1 in influenza virus replication and inflammatory responses. We speculate that STAT1 is an example of a putative antiviral signaling component to support effective replication.