Dihydromyricetin inhibits African swine fever virus replication by downregulating toll-like receptor 4-dependent pyroptosis in vitro

Thonningianin A disrupts pA104R-DNA binding and inhibits African swine fever virus replication

African swine fever is a highly lethal disease caused by the African swine fever virus (ASFV), posing a significant threat to the global pig industry, wherease no approved treatments are currently available. The ASFV DNA-binding protein, pA104R, plays a critical role in viral genome packaging and replication, making it a key target for drug discovery. Through structure-based virtual screening, we identified a polyphenolic compound, thonningianin A, which disrupts the pA104R-DNA binding and significantly inhibits ASFV replication. Mechanistic study revealed that thonningianin A binds to the DNA-binding region of pA104R, forming strong hydrogen bonds with H100 and occupying the vital DNA-binding residues K92, R94, and K97. In addition, we resolved the high-resolution (1.8 Å) structure of pA104R (PDB ID 9JS5), providing valuable insights for future drug screening. Together, these results demonstrate that thonningianin A holds great potential for the development of anti-ASFV drug, as a herb extract with favourable pharmacokinetic properties and safety.

A novel high-throughput screen identifies phenazine-1-carboxylic acid as an inhibitor of African swine fever virus replication in primary porcine alveolar macrophages

African swine fever (ASF), caused by African swine fever virus (ASFV), has resulted in significant economic impacts on the global swine industry. Currently, there is no safe and effective commercial vaccine available for ASFV. Thus, the development of effective and readily available therapeutics for ASF is urgently needed. To conduct high-throughput screening (HTS) for anti-ASFV drugs, we initially developed a recombinant dual-reporter virus (rASFV-Gluc/EGFP) using the virulent strain ASFV HLJ/18 (ASFV-WT). The enhanced green fluorescent protein (EGFP)- and Gaussia luciferase (Gluc)-encoding genes were incorporated downstream of the ASFV MGF300-4L gene without disrupting viral genes. The growth kinetics, hemadsorption, and transmission electron microscopy analysis of rASFV-Gluc/EGFP in primary porcine alveolar macrophages (PAMs) revealed that rASFV-Gluc/EGFP exhibits similar biological characteristics to ASFV-WT. Furthermore, analysis of Gluc activities, fluorescence, and next-generation sequencing indicated that rASFV-Gluc/EGFP maintains good genetic stability after 20 consecutive passages in PAMs. Using the HTS platform established with rASFV-Gluc/EGFP, we screened and identified phenazine-1-carboxylic acid (PCA) as an effective inhibitor of ASFV replication from 246 small molecule compounds in PAMs. Importantly, PCA was found to reduce ASFV replication by as much as 100-fold at a concentration of 25 μM. Overall, this study suggests that rASFV-Gluc/EGFP is suitable for rapid screening of anti-ASFV drugs. Importantly, we showed that PCA has significant anti-ASFV activity in PAMs.

Regulation of macrophage polarization by metformin through inhibition of TLR4/NF-κB pathway to improve pre-eclampsia

INTRODUCTION

Pre-eclampsia (PE) is a pregnancy complication featuring hypertension and proteinuria. Metformin exerts clinically preventive effects on PE with an unspecified mechanism.

METHODS

Placental tissues from PE patients and normal pregnant (NP) women were collected. Twenty-four pregnant mice were divided into control, PE (40 μg/kg lipopolysaccharides (LPS)-induced modeling), aspirin, and metformin groups. After acquisition of bone marrow-derived macrophages (BMDM) and THP-1 cells, cells were categorized into control, LPS (100 ng/mL), metformin, and metformin + toll-like receptor 4 (TLR4) agonist RS 09 groups. Inflammatory factors and macrophage polarization were detected by ELISA, flow cytometry, immunofluorescence, immunohistochemistry, and qRT-PCR methods. TLR4/Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway protein expression was examined using Western blot.

RESULTS

Both PE patients and PE-like mice enhanced inducible nitric oxide synthase (iNOS), TLR4, p-NF-κB/NF-κB, and p-inhibitor of NF-κB (IκBα)/IκBα expression, and lower arginase 1 (Arg-1) expression. Moreover, metformin treatment in PE-like mice increased fetal number and weight and reduced hypertension, proteinuria, insulin resistance, tumor necrosis factor-α (TNF-α), IL-6, IL-1β, chemokine ligand 4 (CCL4), C-X-C motif chemokine ligand 2 (CXCL2) expression and M1 macrophage polarization, with similar inhibition to aspirin. In LPS-induced cells, metformin had the same effects mentioned above. Decreased TLR4, p-NF-κB/NF-κB, and p-IκBα/IκBα protein expression was caused by metformin both in vivo and in vitro. In vitro, RS 09 intervention inhibited anti-inflammatory and pro-M2 polarizing effects of metformin, activating TLR4/NF-κB pathway.

CONCLUSION

Metformin may ameliorate PE by promoting M2 macrophage polarization through up-regulating TLR4/NF-κB pathway, laying theoretical basis for metformin clinical application in PE.

Dihydromyricetin Protects Against Hypoxia/Reoxygenation Injury in Cardiomyocytes by Activating miR-34a-Mediated Notch1 Pathway

Dihydromyricetin (Dih), a naturally occurring flavonoid, has been identified to exert a protective effect against ischemia/reperfusion injury. However, the detailed mechanisms remain unclear. Here we investigated the biological role of Dih in preventing hypoxia/reoxygenation (H/R) injury in cardiomyocytes. The results showed that Dih protected cardiomyocytes against H/R-induced apoptosis, as proved by improved cell viability and decreased lactate dehydrogenase (LDH) release, cell apoptosis percentage, and caspase-3/7 activity. H/R-induced oxidative stress in cardiomyocytes was also prevented by Dih with increased activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), and decreased levels of malondialdehyde (MDA) and reactive oxygen species (ROS). Treatment with Dih prevented H/R-induced increase in the activities of myocardial enzymes aspartate aminotransferase (AST), creatine kinase-MB (CK-MB), and creatine kinase (CK). miR-34a expression was upregulated after H/R stimulation, which could be attenuated by Dih pretreatment. Besides, miR-34a overexpression attenuated the protective effects of Dih against H/R-caused increase in apoptosis, oxidative stress, and myocardial enzyme activities. Next, we demonstrated that Notch1 was a target molecule of miR-34a. Notch1 overexpression reversed the role of miR-34a in regulating the cardioprotective effect of Dih on H/R injury. These observations indicated that the cardioprotective effect of Dih against H/R injury was mediated by the miR-34a/Notch1 signaling. Dih may be a candidate agent for improving the clinical efficacy of cardiac ischemia/reperfusion injury treatment.

Dihydromyricetin: an emerging compound with comprehensive effects on multiple systems

Dihydromyricetin (DHM or DMY) is a flavonoid derived from natural sources with a range of confirmed biological benefits. It exhibits anti-inflammatory, antioxidant, anti-tumor, and anti-viral activities. DHM is recognized for its high biosafety, making it a promising subject for further research. This article offers a comprehensive overview of DHM's pharmacological properties, mechanisms, and recent research developments in the cardiovascular, urinary, digestive, nervous, and respiratory systems. The review summarizes DHM's biological effects and associated signaling pathways, providing novel insights for its clinical application.

African swine fever virus enhances viral replication by increasing intracellular reduced glutathione levels, which suppresses stress granule formation

African swine fever virus (ASFV) is a DNA virus that has significantly impacted the global swine industry. Currently, there are no effective therapies or vaccines against ASFV. Stress granules (SGs), known for their antiviral properties, are not induced during ASFV infection, even though reactive oxygen species (ROS) are generated. The mechanism by which ASFV regulates SGs formation remains unclear. This study demonstrates that ASFV antagonises SGs formation and increases intracellular levels of reduced glutathione (GSH) levels. The use of the GSH inhibitor BSO and the activator NAC confirmed that the ASFV-induced increase in GSH helps to suppress SGs formation and influences viral replication. Additionally, this study revealed that ASFV enhances GSH by upregulating the antioxidant transcription factor NRF2, as well as factors involved in GSH synthesis and regeneration, such as GCLC, and those related to the ferroptosis pathway, such as SLC7A11. Furthermore, the study uncovered that ASFV manipulates intracellular GSH levels by activating the mitochondrial protein AIFM1. This regulatory mechanism helps the virus inhibit the formation of intracellular SGs, thereby creating an optimal environment for viral replication. These findings provide new insights into the molecular strategies employed by ASFV.

Cortisol suppresses lipopolysaccharide-induced in vitro inflammatory response of large yellow croaker (Larimichthys crocea) via the glucocorticoid receptor and p38 mitogen-activated protein kinase pathways

Glucocorticoids (GCs) are well-established anti-inflammatory agents, with cortisol, an endogenous GC, exerting pivotal regulatory effects on normal physiological processes. However, the immune regulatory role of cortisol in teleost fish, particularly in inflammation induced by pathogenic infection, remains largely unexplored. Here, we revealed that lipopolysaccharide (LPS) triggers a pro-inflammatory response in the large yellow croaker (Larimichthys crocea), as evidenced by increased expression of key pro-inflammatory cytokines and activation of the mitogen-activated protein kinase (MAPK) signaling pathway. We further explored the immunosuppressive capacity of cortisol in LPS-stimulated large yellow croaker kidney cells (PCK cells) and in vitro tissues of the large yellow croaker. Our findings indicated that cortisol effectively suppresses LPS-induced overexpression of pro-inflammatory cytokines and p38 MAPK pathway activation. Moreover, the immunosuppressive effects of cortisol were reversed by pretreatment with mifepristone, a glucocorticoid receptor (GR) antagonist. Collectively, this study delineated the inhibitory role of cortisol in the LPS-induced inflammatory cascade in large yellow croaker and underscores the significance of GR in mediating this response. These insights advance our comprehension of GCs-mediated immune modulation and provide a theoretical basis for the application of cortisol in disease prevention and the selective breeding of disease-resistant traits in aquaculture.

Pyroptosis in lung cancer: The emerging role of non-coding RNAs

Lung cancer remains an intractable malignancy worldwide, prompting novel therapeutic modalities. Pyroptosis, a lethal form of programmed cell death featured by inflammation, has been involved in cancer progression and treatment response. Simultaneously, non-coding RNA has been shown to have important roles in coordinating pattern formation and oncogenic pathways, including long non-coding RNA (lncRNAs), microRNA (miRNAs), circular RNA (circRNAs), and small interfering RNA (siRNAs). Recent studies have revealed that ncRNAs can promote or inhibit pyroptosis by interacting with key molecular players such as NLRP3, GSDMD, and various transcription factors. This dual role of ncRNAs offers a unique therapeutic potential to manipulate pyroptosis pathways, providing opportunities for innovative cancer treatments. In this review, we integrate current research findings to propose novel strategies for leveraging ncRNA-mediated pyroptosis as a therapeutic intervention in lung cancer. We explore the potential of ncRNAs as biomarkers for predicting patient response to treatment and as targets for overcoming resistance to conventional therapies.

Cepharanthine inhibits African swine fever virus replication by suppressing AKT-associated pathways through disrupting Hsp90-Cdc37 complex

African swine fever (ASF) represents one of the most economically important viral infectious diseases in the swine industry worldwide. Presently, there is an absence of commercially available therapeutic drugs and safe vaccines. Cepharanthine (CEP), one of the naturally occurring bisbenzylisoquinoline alkaloids, has been approved as a drug to treat various diseases such as leukopenia, bronchial asthma, and snake bites for 70 years in Japan. Most recently, CEP was reported to inhibit ASFV replication by suppressing endosomal/lysosomal function although the specific molecular mechanisms were not elucidated. In this study, we demonstrate for the first time that ASFV infection promotes co-chaperone Cdc37 expression and its binding to Hsp90, leading to increased AKT phosphorylation to benefit viral replication. Notably, CEP disrupts the Hsp90-Cdc37 complex, subsequently decreasing p-AKT and inhibiting ASFV replication. Furthermore, our investigation reveals that enhanced AKT phosphorylation amplifies glycolysis, resulting in increased lactate production, while it upregulates the NF-κB signaling pathway, resulting in increased expression of IL-1β and other inflammatory cytokines. Elevated lactate enhances ASFV replication, and IL-1β acts synergistically on the proviral effect of lactate. CEP reduces ASFV replication by disrupting the formation of the Hsp90-Cdc37 complex and suppressing its downstream AKT/glycolysis axis and AKT/NF-κB pathway, leading to reduced lactate and IL-1β production. Our findings suggest that CEP could serve as a promising ASFV inhibitor, and the Hsp90-Cdc37 complex and glycolysis represent novel antiviral targets against ASFV infections, offering novel avenues for further exploration in antiviral therapeutic strategies. As the in vivo environment is largely complicated from ex vivo PAMs, anti-ASFV efficacy evaluation of CEP in pigs is the most imperative work in the future.

Punicalagin Inhibits African Swine Fever Virus Replication by Targeting Early Viral Stages and Modulating Inflammatory Pathways

African swine fever (ASF), caused by the African swine fever virus (ASFV), has resulted in significant losses in the global pig industry. Considering the absence of effective vaccines, developing drugs against ASFV may be a crucial strategy for its prevention and control in the future. In this study, punicalagin, a polyphenolic substance extracted from pomegranate peel, was found to significantly inhibit ASFV replication in MA-104, PK-15, WSL, and 3D4/21 cells by screening an antiviral compound library containing 536 compounds. Time-of-addition studies demonstrated that punicalagin acted on early viral replication stages, impinging on viral attachment and internalization. Meanwhile, punicalagin could directly inactivate the virus according to virucidal assay. RT-qPCR and Western blot results indicated that punicalagin modulated the NF-κB/STAT3/NLRP3 inflammasome signaling pathway and reduced the levels of inflammatory mediators induced by ASFV. In conclusion, this study reveals the anti-ASFV activity of punicalagin and the mechanism of action, which may have great potential for developing effective drugs against ASFV.

Bis-benzylisoquinoline alkaloids inhibit African swine fever virus internalization and replication by impairing late endosomal/lysosomal function

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a highly infectious disease afflicting domestic pigs and wild boars. It exhibits an alarming acute infection fatality rate of up to 100%. Regrettably, no commercial vaccines or specific drugs for combating this disease are currently available. This study evaluated the anti-ASFV activities in porcine alveolar macrophages, 3D4/21 cells, and PK-15 cells of four bis-benzylisoquinoline alkaloids (BBAs): cepharanthine (CEP), tetrandrine, fangchinoline, and iso-tetrandrine. Furthermore, we demonstrated that CEP, which exhibited the highest selectivity index (SI = 81.31), alkalized late endosomes/lysosomes, hindered ASFV endosomal transport, disrupted virus uncoating signals, and thereby inhibited ASFV internalization. Additionally, CEP disrupted ASFV DNA synthesis, leading to the inhibition of viral replication. Moreover, berbamine was labeled with NBD to synthesize a fluorescent probe to study the cellular location of these BBAs. By co-staining with Lyso-Tracker and lysosome-associated membrane protein 1, we demonstrated that BBAs target the endolysosomal compartments for the first time. Our data together indicated that BBAs are a class of natural products with significant inhibitory effects against ASFV infection. These findings suggest their potential efficacy as agents for the prevention and control of ASF, offering valuable references for the identification of potential drug targets.IMPORTANCEThe urgency and severity of African swine fever (ASF) underscore the critical need for effective interventions against this highly infectious disease, which poses a grave threat to domestic pigs and wild boars. Our study reveals the potent anti-African swine fever virus (ASFV) efficacy of bis-benzylisoquinoline alkaloids (BBAs), particularly evident in the absence of progeny virus production under a 5 µM concentration treatment. The structural similarity among cepharanthine, tetrandrine, fangchinoline, and iso-tetrandrine, coupled with their analogous inhibitory stages and comparable selectivity indexes, strongly suggests a shared antiviral mechanism within this drug category. Further investigation revealed that BBAs localize to lysosomes and inhibit the internalization and replication of ASFV by disrupting the endosomal/lysosomal function. These collective results have profound implications for ASF prevention and control, suggesting the potential of the investigated agents as prophylactic and therapeutic measures. Furthermore, our study offers crucial insights into identifying drug targets and laying the groundwork for innovative interventions.

Dihydromyricetin improves growth performance, immunity, and intestinal functions in weaned pigs challenged by enterotoxigenic Escherichia coli

Enteric infection is a major cause of enteric disorder in neonatal pigs during the weaning transition. Dihydromyricetin (DMY) is a natural flavanonol compound extracted from Ampelopsis grossedentata with numerous biological activities such as antioxidative and immunomodulatory functions. The objective of this study was to investigate the effects of dietary dihydromyricetin supplementation on growth performance, immunity, and intestinal functions in weaned pigs challenged by enterotoxigenic Escherichia coli (ETEC). In total, 24 weaned DLY (Duroc × Landrace × Yorkshire) pigs were allotted to 3 treatments. Pigs fed with basal diet or basal diet containing 300 mg/kg DMY were orally infused with sterilized culture or ETEC (2.5 × 1011 colony-forming units). Dietary DMY supplementation significantly elevated the final weight and average daily gain (ADG) but reduced diarrhea incidence in the weaned pigs of the EDMY group compared to the pigs of the ECON group (p < 0.05). Compared to the ECON group, DMY also improved the digestibility of dry matter (DM), ether extract (EE), gross energy (GE), and ash of the EDMY group (p < 0.05). Moreover, DMY not only significantly decreased the ratio of albumin/globulin but also elevated serum concentrations of immunoglobulins (e.g., IgA and IgG) in the weaned pigs of the EDMY group compared to the pigs of the ECON group (p < 0.05). Interestingly, the villus height, the ratio of villus height to crypt depth (V:C), and the activities of mucosal alkaline phosphatase, sucrase, and maltase in the duodenum and jejunum of the EDMY group were higher than those in the ECON group (p < 0.05). Importantly, DMY significantly elevated the expression levels of jejunal zonula occludens-1 (ZO-1), claudin-1, cationic amino acid transporter-1 (CAT-1), and fatty acid transport protein-1 (FATP-1) in the weaned pigs of the EDMY group compared to the pigs of the ECON group (p < 0.05). Additionally, compared to the ECON group, DMY increased the concentrations of microbial SCFA metabolites (e.g., acetic acid and propanoic acid), but reduced the abundance of Escherichia coli in the cecum of the EDMY group (p < 0.05). Dietary DMY supplementation can attenuate the ETEC-induced growth retardation and intestinal injury, which was attributed to the amelioration of intestinal nutrient digestion and transport functions as well as the improved microbiota.

Fangchinoline Inhibits African Swine Fever Virus Replication by Suppressing the AKT/mTOR/NF-κB Signaling Pathway in Porcine Alveolar Macrophages

African swine fever (ASF), caused by the African swine fever virus (ASFV), is one of the most important infectious diseases that cause high morbidity and mortality in pigs and substantial economic losses to the pork industry of affected countries due to the lack of effective vaccines. The need to develop alternative robust antiviral countermeasures, especially anti-ASFV agents, is of the utmost urgency. This study shows that fangchinoline (FAN), a bisbenzylisoquinoline alkaloid found in the roots of Stephania tetrandra of the family Menispermaceae, significantly inhibits ASFV replication in porcine alveolar macrophages (PAMs) at micromolar concentrations (IC50 = 1.66 µM). Mechanistically, the infection of ASFV triggers the AKT/mTOR/NF-κB signaling pathway. FAN significantly inhibits ASFV-induced activation of such pathways, thereby suppressing viral replication. Such a mechanism was confirmed using an AKT inhibitor MK2206 as it inhibited AKT phosphorylation and ASFV replication in PAMs. Altogether, the results suggest that the AKT/mTOR pathway could potentially serve as a treatment strategy for combating ASFV infection and that FAN could potentially emerge as an effective novel antiviral agent against ASFV infections and deserves further in vivo antiviral evaluations.

Advances in research on the efficacy of traditional Chinese herbal medicine in combating African swine fever

African swine fever (ASF) is a highly contagious disease of domestic and wild pigs caused by African swine fever virus (ASFV). The mortality rate associated with ASF is remarkably high, almost approaching 100%. Since the introduction of ASF into China in 2018, its rapid spread has caused marked economic losses in the country’s swine industry. To date, there are no safe and effective commercial vaccines or antiviral drugs against ASF; thus, there is an urgent need to develop novel prevention and control strategies. Traditional Chinese medicine (TCM), which comprises various herbs that are abundant in various potential functional components, holds great promise for the prevention and control of ASF. Here, we provide a comprehensive review of the advancements in TCM and the effects of its compound formulas against ASF, including the antiviral abilities, immunoregulatory activities, and practical application of these formulas for the prevention and control of ASF. We specifically examined the potential and constraints of natural product-derived extracts and TCM formulas in combating ASFV. This review aims to offer insights and ideas for the holistic management and containment of ASF.

Noncoding RNAs as therapeutic targets in autophagy-related diabetic cardiomyopathy

Diabetic cardiomyopathy, a multifaceted complication of diabetes mellitus, remains a major challenge in clinical management due to its intricate pathophysiology. Emerging evidence underscores the pivotal role of autophagy dysregulation in the progression of diabetic cardiomyopathy, providing a novel avenue for therapeutic intervention. Noncoding RNAs (ncRNAs), a diverse class of regulatory molecules, have recently emerged as promising candidates for targeted therapeutic strategies. The exploration of various classes of ncRNAs, including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) reveal their intricate regulatory networks in modulating autophagy and influencing the pathophysiological processes associated with diabetic cardiomyopathy. The nuanced understanding of the molecular mechanisms underlying ncRNA-mediated autophagic regulation offers a rationale for the development of precise and effective therapeutic interventions. Harnessing the regulatory potential of ncRNAs presents a promising frontier for the development of targeted and personalized therapeutic strategies, aiming to ameliorate the burden of diabetic cardiomyopathy in affected individuals. As research in this field advances, the identification and validation of specific ncRNA targets hold immense potential for the translation of these findings into clinically viable interventions, ultimately improving outcomes for patients with diabetic cardiomyopathy. This review encapsulates the current understanding of the intricate interplay between autophagy and diabetic cardiomyopathy, with a focus on the potential of ncRNAs as therapeutic targets.

The natural compound Sanggenon C inhibits PRRSV infection by regulating the TRAF2/NF-κB signalling pathway

Porcine reproductive and respiratory syndrome (PRRS) is a serious infectious disease and one of the major causes of death in the global pig industry. PRRS virus (PRRSV) strains have complex and diverse genetic characteristics and cross-protection between strains is low, which complicates vaccine selection; thus, the current vaccination strategy has been greatly compromised. Therefore, it is necessary to identify effective natural compounds for the clinical treatment of PRRS. A small molecule library composed of 720 natural compounds was screened in vitro, and we found that Sanggenon C (SC) was amongst the most effective natural compound inhibitors of PRRSV infection. Compared with ribavirin, SC more significantly inhibited PRRSV infection at both the gene and protein levels and reduced the viral titres and levels of protein expression and inflammatory cytokine secretion to more effectively protect cells from PRRSV infection and damage. Mechanistically, SC inhibits activation of the NF-κB signalling pathway by promoting TRAF2 expression, thereby reducing PRRSV replication. In conclusion, by screening natural compounds, we found that SC suppresses PRRSV infection by regulating the TRAF2/NF-κB signalling pathway. This study contributes to a deeper understanding of the therapeutic targets and pathogenesis of PRRSV infection. More importantly, our results demonstrate that SC has potential as a candidate for the treatment of PRRS.