The compound packaged in virions is the key to trigger host glycolysis machinery for virus life cycle in the cytoplasm

Virus-Induced Histone Lactylation Promotes Virus Infection in Crustacean

As "non-cellular organisms", viruses need to infect living cells to survive themselves. The virus infection must alter host's metabolisms. However, the influence of the metabolites from the altered metabolisms of virus-infected host cells on virus-host interactions remains largely unclear. To address this issue, shrimp, a representative species of crustaceans, is challenged with white spot syndrome virus (WSSV) in this study. The in vivo results presented that the WSSV infection enhanced shrimp glycolysis, leading to the accumulation of lactate. The lactate accumulation in turn promoted the site-specific histone lactylation (H3K18la and H4K12la) in a p300/HDAC1/HDAC3-dependent manner. H3K18la and H4K12la are enriched in the promoters of 75 target genes, of which the H3K18la and H4K12la modification upregulated the expression of ribosomal protein S6 kinases 2 (S6K2) in the virus-infected hosts to promote the virus infection. Further data revealed that the virus-encoded miR-N20 targeted hypoxia inducible factor-1α (HIF-1α) to inhibit the host glycolysis, leading to the suppression of H3K18la and H4K12la. Therefore, the findings contributed novel insights into the effects and the underlying mechanism of the virus-induced histone lactylation on the virus-host interactions, providing new targets for the control of virus infection.

Commensal microbiota-derived metabolite agmatine triggers inflammation to promote colorectal tumorigenesis

Colorectal cancer (CRC), a malignant tumor worldwide, is associated with gut microbiota. The influence of gut microbe-derived metabolites on CRC has attracted a lot of attention. However, the role of immunity mediated by commensal microbiota-derived metabolites in tumorigenesis of CRC is not intensively explored. Here we monitored the gut microbial dysbiosis in CRC mouse model (ApcMin/+ model) without dietary and pharmacological intervention, followed by characterized of metabolites enriched in CRC model mice. Profound changes of gut microbiome (bacteriome) were observed during intestinal disorders. Metabolomic profiling indicated that agmatine, derived from the gut bacteria i.e. Blautia, Odoribacter, Alistipes and Paraprevotella, could interact with Rnf128 to suppress the Rnf128-mediated ubiquitination of β-catenin to further upregulate the downstream targets of β-catenin including Cyclin D1, Lgr5, CD44 and C-myc, thus activating Wnt signaling. The activated Wnt signaling pathway promoted dysplasia of intestinal cells and inflammatory infiltration of lymphocytes via inducing the upregulation of pro-inflammatory cytokines (IL-6 and TNF-α) and downregulation of anti-inflammatory cytokine (IL-10), thereby contributing to colorectal carcinogenesis. Therefore, our study presented novel insights into the roles and mechanisms of gut microbiota in pathogenesis of CRC.

Transcriptomic analysis reveals the role of Glycolysis pathway in Litopenaeus vannamei during DIV1 infection

In recent years, shrimp farming has experienced significant losses due to the emergence of DIV1 (Decapod iridescent virus 1), an infectious virus with a high fatality rate among shrimp. In this study, we conducted transcriptomic analyses on shrimp Litopenaeus vannamei hemocytes following DIV1 infection and focused on the function of genes in the Glycolysis pathway during DIV1 infection. A total of 2197 differentially expressed genes (DEGs) were identified, comprising 1506 up-regulated genes and 691 down-regulated genes. These genes were primarily associated with Phagosome, ECM-Receptor Interaction, Drug Metabolism-Other Enzymes, and the AGE-RAGE signaling pathway in diabetic complications. KEGG pathway enrichment analysis of the DEGs revealed a noteworthy correlation with metabolic pathways, with a specific focus on glucose metabolism. Specifically, the Glycolysis/Gluconeogenesis pathway exhibited significant upregulation following DIV1 infection. In line with this, we observed an augmented accumulation of glycolytic-related metabolites in the hemolymph following DIV1 challenge along with upregulation of the relative mRNA expression of several glycolytic-related genes. Moreover, we found that the inhibition of lactate dehydrogenase (LDH) activity through RNAi or the use of an inhibitor resulted in reduced lactate production, effectively safeguarding shrimp from DIV1 infection. These findings not only provide a comprehensive dataset for further investigation into DIV1 pathogenesis but also offer valuable insights into the immunometabolism mechanisms that govern shrimp responses to DIV1 infection.

Serum metabolomic analysis reveals key metabolites in drug treatment of central precocious puberty in female children

Precocious puberty (PP) is a common condition among children. According to the pathogenesis and clinical manifestations, PP can be divided into central precocious puberty (CPP, gonadotropin dependent), peripheral precocious puberty (PPP, gonadotropin independent), and incomplete precocious puberty (IPP). Identification of the variations in key metabolites involved in CPP and their underlying biological mechanisms has increased the understanding of the pathological processes of this condition. However, little is known about the role of metabolite variations in the drug treatment of CPP. Moreover, it remains unclear whether the understanding of the crucial metabolites and pathways can help predict disease progression after pharmacological therapy of CPP. In this study, systematic metabolomic analysis was used to examine three groups, namely, healthy control (group N, 30 healthy female children), CPP (group S, 31 female children with CPP), and treatment (group R, 29 female children) groups. A total of 14 pathways (the top two pathways were aminoacyl-tRNA biosynthesis and phenylalanine, tyrosine, and tryptophan biosynthesis) were significantly enriched in children with CPP. In addition, two short peptides (His-Arg-Lys-Glu and Lys-Met-His) were found to play a significant role in CPP. Various metabolites associated with different pathways including amino acids, PE [19:1(9Z)0:0], tumonoic acid I, palmitic amide, and linoleic acid-biotin were investigated in the serum of children in all groups. A total of 45 metabolites were found to interact with a chemical drug [a gonadotropin-releasing hormone (GnRH) analog] and a traditional Chinese medicinal formula (DBYW). This study helps to understand metabolic variations in CPP after drug therapy, and further investigation may help develop individualized treatment approaches for CPP in clinical practice.

Exosomes from WSSV-infected shrimp contain viral components that mediate virus infection

Exosomes have been described as vesicles that mediate intercellular communication and thus affect normal and pathological processes. Furthermore, many viruses have been reported to deliver viral components to host cells through exosomes. However, the roles of exosomes in invertebrates response to virus infection are poorly understood. In this study, we found that exosomes purified from white spot syndrome virus (WSSV)-infected hemocytes of shrimp could promote viral replication. These exosomes contained WSSV genomic DNA and nucleocapsid protein VP15, suggesting that exosomes can transfer viral genetic materials between cells, although the exosomes did not have similar infection ability to viruses. Remarkably, in exosomes WSSV DNA was bound to VP15 protein, and moreover VP15 silencing significantly suppressed WSSV infection and reduced the WSSV genome fragments in exosomes, indicating that the presence of VP15 is required for the packing of WSSV DNA inside the exosomes and thereby assists virus to complete immune escape. The above results not only contribute to elucidation of the infection and transmission mechanisms of WSSV, but are also of great significance for further study of virus-host interaction and reasonable prevention measures. Taken together, our findings provide a novel insight into the regulation of virus transmission via exosomes and highlight potential therapeutic strategies.

Melatonin: Regulation of Viral Phase Separation and Epitranscriptomics in Post-Acute Sequelae of COVID-19

The relentless, protracted evolution of the SARS-CoV-2 virus imposes tremendous pressure on herd immunity and demands versatile adaptations by the human host genome to counter transcriptomic and epitranscriptomic alterations associated with a wide range of short- and long-term manifestations during acute infection and post-acute recovery, respectively. To promote viral replication during active infection and viral persistence, the SARS-CoV-2 envelope protein regulates host cell microenvironment including pH and ion concentrations to maintain a high oxidative environment that supports template switching, causing extensive mitochondrial damage and activation of pro-inflammatory cytokine signaling cascades. Oxidative stress and mitochondrial distress induce dynamic changes to both the host and viral RNA m6A methylome, and can trigger the derepression of long interspersed nuclear element 1 (LINE1), resulting in global hypomethylation, epigenetic changes, and genomic instability. The timely application of melatonin during early infection enhances host innate antiviral immune responses by preventing the formation of "viral factories" by nucleocapsid liquid-liquid phase separation that effectively blockades viral genome transcription and packaging, the disassembly of stress granules, and the sequestration of DEAD-box RNA helicases, including DDX3X, vital to immune signaling. Melatonin prevents membrane depolarization and protects cristae morphology to suppress glycolysis via antioxidant-dependent and -independent mechanisms. By restraining the derepression of LINE1 via multifaceted strategies, and maintaining the balance in m6A RNA modifications, melatonin could be the quintessential ancient molecule that significantly influences the outcome of the constant struggle between virus and host to gain transcriptomic and epitranscriptomic dominance over the host genome during acute infection and PASC.

Palmitic Amide Triggers Virus Life Cycle via Enhancing Host Energy Metabolism

Viruses contribute to the mortality of organisms, consequentially altering biological species composition of an ecosystem and having a threat on human health. As the most famous model for the initiation of virus infection, the Hershey-Chase experiment has revealed that on infection, the bacteriophage genomic DNA is injected into its host bacterium, while the viral capsid is left on the outer membrane of host cell. However, little is known about the injection of any other materials into the cytoplasm of host cells along with genomic DNA to trigger the virus life cycle. In this study, the results showed that palmitic amide packaged in the virions of GVE2, a bacteriophage infecting deep-sea hydrothermal vent thermophile Geobacillus sp. E263, promoted virus infection. Palmitic amide was interacted with acetate kinase to increase its enzymatic activity, thus enhancing the acetate-mediated energy metabolism. Furthermore, palmitic amide promoted tricarboxylic acid cycle (TCA cycle) to support virus infection. These data indicated that palmitic amide, packaged in the virions, might serve as a second messenger at the initiation step of virus infection by enhancing the host energy metabolism. Therefore our study revealed a novel mechanism for the initiation of the virus life cycle.

Dynamic N6-methyladenosine modification of lncRNA modulated by METTL3 during bacterial disease development in an echinoderm

Long non-coding RNAs (lncRNAs) are novel functional non-coding RNAs which engaged in many aspects of biological processes. N6-methyladenosine (m6A) as a kind of abundant epitranscriptomic modification in eukaryotes, plays important roles in regulation of gene expression for various physiological functions. Our previous study demonstrated that sea cucumber lncRNAs were differentially expressed during bacterial infection. However, whether the post-transcriptional regulation of lncRNAs influenced by m6A modification in sea cucumbers with different stages of skin ulceration syndrome (SUS) are largely unknown. Here, we generated the genome-wide map of m6A lncRNAs in SUS-diseased and SUS-resistant sea cucumbers for the first time, revealed that m6A levels in lncRNAs were mainly upregulated in SUS-resistant group. Intriguingly, most of the m6A lncRNAs showed a positive correlation between the expression levels and m6A levels based on conjoint analysis, suggesting that m6A modification on a lncRNA may contribute to its RNA stability. Furthermore, the host genes of lncRNAs with dysregulated m6A peaks were enriched in immune pathway. More importantly, methyltransferase METTL3 was required for m6A methylation modification and played positive roles in lncRNA expression. Collectively, this study presents the comprehensive characters of m6A lncRNAs in marine invertebrate. These m6A modified lncRNAs may be served as potential regulators associated with SUS and provide a promising avenue for disease therapy through targeting METTL3.

Core Gut Microbiota of Shrimp Function as a Regulator to Maintain Immune Homeostasis in Response to WSSV Infection

The gut microbiota is an integral part of the host and has a functional potential in host physiology. Numerous scientific efforts have opened new horizons in gut microbiota research and enhanced the understanding of host-microbe interactions in vertebrates. However, evidence on the association between the gut microbiota and immunity in invertebrates, especially in shrimp, which is an important aquatic animal, is limited. Herein, we conducted a comprehensive analysis based on 16S rRNA gene sequencing and liquid chromatography-coupled mass spectrometry (LC-MS) to investigate the correlation between them. Comparing the gut microbiota among the four different species of shrimp, we found huge variations and determined a core gut microbiota composed of 55 microbes. The environmental challenge of white spot syndrome virus (WSSV) infection led to changes in core microbial structures, but the alteration of core microbiota among different shrimp followed the same trend and showed immune-related function in the prediction of its metabolic potential. In metabolomic analysis, nine significantly upregulated metabolites found after viral infection indicated that they have antiviral potential. Moreover, we found a tight correlation between them and almost half of the core microbiota. These data demonstrate that these metabolites are responsible for maintaining the immune homeostasis of the host and prove the function of the gut microbiota and the related metabolome in antiviral immunity of shrimp.

IMPORTANCE Abundant gut microorganisms constitute a complex microecosystem with the intestinal environment of the host, which plays a critical role in the adjustment of various physiological states of the organism. Sequencing and mass spectrometry data collected from intestinal samples of shrimp after virus infection helped to investigate the special function of the microecosystem and suggested that the gut microbiota has a functional potential in maintaining immune homeostasis of the host under environmental challenge.

Antiviral strategies targeting host factors and mechanisms obliging +ssRNA viral pathogens

The ongoing COVID-19 pandemic, periodic recurrence of viral infections, and the emergence of challenging variants has created an urgent need of alternative therapeutic approaches to combat the spread of viral infections, failing to which may pose a greater risk to mankind in future. Resilience against antiviral drugs or fast evolutionary rate of viruses is stressing the scientific community to identify new therapeutic approaches for timely control of disease. Host metabolic pathways are exquisite reservoir of energy to viruses and contribute a diverse array of functions for successful replication and pathogenesis of virus. Targeting the host factors rather than viral enzymes to cease viral infection, has emerged as an alternative antiviral strategy. This approach offers advantage in terms of increased threshold to viral resistance and can provide broad-spectrum antiviral action against different viruses. The article here provides substantial review of literature illuminating the host factors and molecular mechanisms involved in innate/adaptive responses to viral infection, hijacking of signalling pathways by viruses and the intracellular metabolic pathways required for viral replication. Host-targeted drugs acting on the pathways usurped by viruses are also addressed in this study. Host-directed antiviral therapeutics might prove to be a rewarding approach in controlling the unprecedented spread of viral infection, however the probability of cellular side effects or cytotoxicity on host cell should not be ignored at the time of clinical investigations.