Berberine prevents lethal EV71 neurological infection in newborn mice

Metformin inhibits EV-A71 and CVA16 infections by regulating TRIB3-SCARB2 axis and activating AMPK

Our previous study had found that cellular pseudokinase tribbles 3 (TRIB3) facilitates the infection of enterovirus A71 (EV-A71) via upregulating the protein level of EV-A71 receptor scavenger receptor class B member 2 (SCARB2). In the present study, we used metformin, which had been reported to down-regulate TRIB3 expression, to verify the potential of TRIB3 as an antiviral target. Here, we found that metformin can indeed impede the replication of EV-A71 and Coxsackievirus A16 (CVA16) through inhibiting the transcription of TRIB3 to indirectly down-regulate SCARB2 protein levels to block viral infection. Importantly, we also found that metformin can inhibit the replication of EV-A71 and CVA16 in a TRIB3-independent manner. In fact, we found that both metformin and cellular AMP-activated protein kinase (AMPK) agonist AICAR can inhibit the replication of EV-A71 and CVA16 by pharmacologically activating AMPK. Moreover, AMPK phosphorylation specific inhibitor Compound C treatment can reverse the antiviral effect of metformin, indicating that metformin can indeed play an antiviral role through regulating AMPK. More importantly, we confirmed that metformin could effectively protected mice from lethal EV-A71 infection. Metformin treatment decreased the levels of EV-A71 VP1 protein and viral RNA in the infected muscles, and improved muscle pathology. These findings suggest that TRIB3 does have potential as a target for antiviral drugs, and metformin may be a potential agent or supplement against enterovirus infection.

Enterovirus-A71 preferentially infects and replicates in human motor neurons, inducing neurodegeneration by ferroptosis

Enterovirus A71 (EV-A71) causes Hand, Foot, and Mouth Disease and has been clinically associated with neurological complications. However, there is a lack of relevant models to elucidate the neuropathology of EV-A71 and its mechanism, as the current models mainly utilize animal models or immortalized cell lines. In this study, we established a human motor neuron model for EV-A71 infection. Single cell transcriptomics of a mixed neuronal population reveal higher viral RNA load in motor neurons, suggesting higher infectivity and replication of EV-A71 in motor neurons. The elevated RNA load in motor neurons correlates with the downregulation of ferritin-encoding genes. Subsequent analysis confirms that neurons infected with EV-A71 undergo ferroptosis, as evidenced by increased levels of labile Fe2+ and peroxidated lipids. Notably, the Fe2+ chelator Deferoxamine improves mitochondrial function and promotes survival of motor neurons by 40% after EV-A71 infection. These findings deepen understanding of the molecular pathogenesis of EV-A71 infection, providing insights which suggest that improving mitochondrial respiration and inhibition of ferroptosis can mitigate the impact of EV-A71 infection in the central nervous system.

Berberine promotes K48-linked polyubiquitination of HNF4α, leading to the inhibition of HBV replication

The current antiviral agents for the treatment of chronic infection with hepatitis B virus (HBV) do not completely remove covalently closed circular DNA (cccDNA) and integrated viral DNA fragments from patients. Berberine is an isoquinoline alkaloid extracted from various plants and has been reported to inhibit the replication of various types of DNA. In this study, we tested the effects of berberine and its derivatives on HBV infection. Berberine inhibited viral core promoter activity at the highest level among the compounds tested and suppressed HBV production and cccDNA synthesis in primary human hepatocytes and HBV-infected HepG2-NTCP cells at an EC50 value of 3.6 μM and a CC50 value of over 240.0 μM. Compared with other viral promoter activities, berberine treatment potently downregulated core promoter activity and reduced protein levels, but not RNA levels, of hepatic nuclear factor 4α (HNF4α), which primarily enhances enhancer II/core promoter activity. Furthermore, berberine treatment enhanced K48-linked, but not K63-linked, polyubiquitination and subsequent proteasome-dependent degradation of HNF4α. These results suggest that berberine enhances the polyubiquitination- and proteasome-dependent degradation of HNF4α and then inhibits HBV replication via the suppression of core promoter activity. The development of antiviral agents based on berberine may contribute to the amelioration of HBV-related disorders, regardless of the presence of residual cccDNA or integrated viral DNA fragments.

Pathogenicity and transcriptomic profiling reveals immunology molecular hallmarks after CA10 virus infection

BACKGROUND

Hand, foot and mouth disease (HFMD) is a common infectious disease caused by viral infection by a variety of enteroviruses, with coxsackievirus A 10 (CA10) having become more prevalent in recent years.

METHODS

In this study, models of CA10 infection were established in 7-day-old Institute of Cancer Research (ICR) mice by intraperitoneal injection to analyze the pathogenicity of the virus. RNA sequencing analysis was used to screen the differentially expressed genes (DEGs) after CA10 infection. Coxsackievirus A 16 (CA16) and enterovirus 71 (EV71) infections were also compared with CA10.

RESULTS

After CA10 virus infection, the mice showed paralysis of the hind limbs at 3 days post infection and weight loss at 5 days post infection. We observed viral replication in various tissues and severe inflammatory cell infiltration in skeletal muscle. The RNA-sequencing analysis showed that the DEGs in blood, muscle, thymus and spleen showed heterogeneity after CA10 infection and the most up-regulated DEGs in muscle were enriched in immune-related pathways. Compared with CA16 and EV71 infection, CA10 may have an inhibitory effect on T helper (Th) cell differentiation and cell growth. Additionally, the common DEGs in the three viruses were most enriched in the immune system response, including the Toll-like receptor pathway and the nucleotide-binding and oligomerization domain (NOD)-like pathway.

CONCLUSIONS

Our findings revealed a group of genes that coordinate in response to CA10 infection, which increases our understanding of the pathological mechanism of HFMD.

Metabolomics combined with network pharmacology reveals a role for astragaloside IV in inhibiting enterovirus 71 replication via PI3K-AKT signaling

BACKGROUND

Astragaloside IV (AST-IV), as an effective active ingredient of Astragalus membranaceus (Fisch.) Bunge. It has been found that AST-IV inhibits the replication of dengue virus, hepatitis B virus, adenovirus, and coxsackievirus B3. Enterovirus 71 (EV71) serves as the main pathogen in severe hand-foot-mouth disease (HFMD), but there are no specific drugs available. In this study, we focus on investigating whether AST-IV can inhibit EV71 replication and explore the potential underlying mechanisms.

METHODS

The GES-1 or RD cells were infected with EV71, treated with AST-IV, or co-treated with both EV71 and AST-IV. The EV71 structural protein VP1 levels, the viral titers in the supernatant were measured using western blot and 50% tissue culture infective dose (TCID50), respectively. Network pharmacology was used to predict possible pathways and targets for AST-IV to inhibit EV71 replication. Additionally, ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) was used to investigate the potential targeted metabolites of AST-IV. Associations between metabolites and apparent indicators were performed via Spearman's algorithm.

RESULTS

This study illustrated that AST-IV effectively inhibited EV71 replication. Network pharmacology suggested that AST-IV inhibits EV71 replication by targeting PI3K-AKT. Metabolomics results showed that AST-IV achieved these effects by elevating the levels of hypoxanthine, 2-ketobutyric acid, adenine, nicotinic acid mononucleotide, prostaglandin H2, 6-hydroxy-1 H-indole-3- acetamide, oxypurinol, while reducing the levels of PC (14:0/15:0). Furthermore, AST-IV also mitigated EV71-induced oxidative stress by reducing the levels of MDA, ROS, while increasing the activity of T-AOC, CAT, GSH-Px. The inhibition of EV71 replication was also observed when using the ROS inhibitor N-Acetylcysteine (NAC). Additionally, AST-IV exhibited the ability to activate the PI3K-AKT signaling pathway and suppress EV71-induced apoptosis.

CONCLUSION

This study suggests that AST-IV may activate the cAMP and the antioxidant stress response by targeting eight key metabolites, including hypoxanthine, 2-ketobutyric acid, adenine, nicotinic acid mononucleotide, prostaglandin H2, 6-Hydroxy-1 H-indole-3-acetamide, oxypurinol and PC (14:0/15:0). This activation can further stimulate the PI3K-AKT signaling to inhibit EV71-induced apoptosis and EV71 replication.

Anti-inflammatory, antioxidant, and immunomodulatory effects of Berberis vulgaris and its constituent berberine, experimental and clinical, a review

Berberis vulgaris (B. vulgaris or barberry) is a medicinal plant that has been used for various purposes in traditional medicine. Berberine is one of the main alkaloids isolated from B. vulgaris and other plants. Both B. vulgaris and berberine have shown anti-inflammatory, antioxidant, and immunomodulatory effects in different experimental models and clinical trials. This review aims to summarize the current evidence on the mechanisms and applications of B. vulgaris and berberine in modulating inflammation, oxidative stress, and immune responses. The literature search was performed using PubMed, Scopus, and Google Scholar databases until August 2023. The results indicated that B. vulgaris and berberine could inhibit the production of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), interleukin 6 (IL-6), and interleukin-17 (IL-17), and enhance the expression of anti-inflammatory cytokines, such as interleukin 10 (IL-10) and transforming growth factor-β (TGF-β), in various cell types and tissues. B. vulgaris and berberine can also scavenge free radicals, increase antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and reduce lipid peroxidation and DNA damage. B. vulgaris and berberine have been reported to exert beneficial effects in several inflammatory, oxidative, and immune-related diseases, such as diabetes, obesity, cardiovascular diseases, neurodegenerative diseases, autoimmune diseases, allergic diseases, and infections. However, more studies are needed to elucidate the optimal doses, safety profiles, and potential interactions of B. vulgaris and berberine with other drugs or natural compounds.

Pathogenicity and landscape of differential gene expression in mice orally infected with clinical coxsackievirus A6 (CA6)

Hand, foot, and mouth disease (HFMD) is caused by more than 20 pathogenic enteroviruses belonging to the Picornaviridae family and Enterovirus genus. Since the introduction of the enterovirus-71 (EV71) vaccine in 2016, the number of HFMD cases caused by EV71 has decreased. However, cases of infections caused by other enteroviruses, such as coxsackievirus A6 (CA6) and coxsackievirus A10, have been increasing accordingly. In this study, we used a clinical isolate of CA6 to establish an intragastric infection mouse model using 7-day-old mice to mimic the natural transmission route, by which we investigated the differential gene expression profiles associated with virus infection and pathogenicity. After intragastric infection, mice exhibited hind limb paralysis symptoms and weight loss, similar to those reported for EV71 infection in mice. The skeletal muscle was identified as the main site of virus replication, with a peak viral load reaching 2.31 × 107 copies/mg at 5 dpi and increased infiltration of inflammatory cells. RNA sequencing analysis identified differentially expressed genes (DEGs) after CA6 infection. DEGs in the blood, muscle, brain, spleen, and thymus were predominantly enriched in immune system responses, including pathways such as Toll-like receptor signaling and PI3K-Akt signaling. Our study has unveiled the genes involved in the host immune response during CA6 infection, thereby enhancing our comprehension of the pathological mechanism of HFMD.IMPORTANCEThis study holds great significance for the field of hand, foot, and mouth disease (HFMD). It not only delves into the disease's etiology, transmission pathways, and severe complications but also establishes a novel mouse model that mimics the natural coxsackievirus A6 infection process, providing a pivotal platform to delve deeper into virus replication and pathogenic mechanisms. Additionally, utilizing RNA-seq technology, it unveils the dynamic gene expression changes during infection, offering valuable leads for identifying novel therapeutic drug targets. This research has the potential to enhance our understanding of HFMD, offering fresh perspectives for disease prevention and treatment and positively impacting children's health worldwide.

Recent Applications of Protoberberines as Privileged Starting Materials for the Development of Novel Broad-Spectrum Antiviral Agents: A Concise Review (2017-2023)

Berberine is a well-known phytochemical with significant antiviral activity against a wide range of viruses. Due to having a unique backbone consisting of four interconnected rings, it can be used as a platform for the design and development of novel semisynthetic antiviral agents. The question here is whether novel broad-spectrum antiviral drugs with enhanced activity and toxicity potential can be obtained by attempting to modify the structure of this privileged lead compound. The present study aims to review the results of recent studies in which berberine and its close analogues (protoberberine alkaloids) have been used as starting materials for the production of new semisynthetic antiviral structures. For this purpose, relevant studies published in high-quality journals indexed in databases such as Scopus, Web of Science, PubMed, etc. in the time frame of 2017 to 2023 were collected. Our selection criterion in the current review focuses on the studies in which protoberberines were used as starting materials for the production of semisynthetic agents with antiviral activity during the indicated time period. Correspondingly, studies were identified in which semisynthetic derivatives with significant inhibitory activity against a wide range of viruses including human immunodeficiency virus (HIV), enterovirus 71 (EV71), zika virus (ZIKV), influenza A/B, cytomegalovirus (CMV), respiratory syncytial virus (RSV), and coxsackieviruses were designed and synthesized. Our conclusion is that, despite the introduction of diverse semisynthetic derivatives of berberine with improved activity profiles compared to the parent natural leads, sufficient derivatization has not been done yet and more studies are needed.

Network pharmacology-based exploration identified the antiviral efficacy of Quercetin isolated from mulberry leaves against enterovirus 71 via the NF-κB signaling pathway

Introduction: Mulberry leaf (ML) is known for its antibacterial and anti-inflammatory properties, historically documented in "Shen Nong's Materia Medica". This study aimed to investigate the effects of ML on enterovirus 71 (EV71) using network pharmacology, molecular docking, and in vitro experiments. Methods: We successfully pinpointed shared targets between mulberry leaves (ML) and the EV71 virus by leveraging online databases. Our investigation delved into the interaction among these identified targets, leading to the identification of pivotal components within ML that possess potent anti-EV71 properties. The ability of these components to bind to the targets was verified by molecular docking. Moreover, bioinformatics predictions were used to identify the signaling pathways involved. Finally, the mechanism behind its anti-EV71 action was confirmed through in vitro experiments. Results: Our investigation uncovered 25 active components in ML that targeted 231 specific genes. Of these genes, 29 correlated with the targets of EV71. Quercetin, a major ingredient in ML, was associated with 25 of these genes. According to the molecular docking results, Quercetin has a high binding affinity to the targets of ML and EV71. According to the KEGG pathway analysis, the antiviral effect of Quercetin against EV71 was found to be closely related to the NF-κB signaling pathway. The results of immunofluorescence and Western blotting showed that Quercetin significantly reduced the expression levels of VP1, TNF-α, and IL-1β in EV71-infected human rhabdomyosarcoma cells. The phosphorylation level of NF-κB p65 was reduced, and the activation of NF-κB signaling pathway was suppressed by Quercetin. Furthermore, our results showed that Quercetin downregulated the expression of JNK, ERK, and p38 and their phosphorylation levels due to EV71 infection. Conclusion: With these findings in mind, we can conclude that inhibiting the NF-κB signaling pathway is a critical mechanism through which Quercetin exerts its anti-EV71 effectiveness.