An invertebrate Warburg effect: a shrimp virus achieves successful replication by altering the host metabolome via the PI3K-Akt-mTOR pathway

Triple jeopardy: The combined effects of viral, chemical, and thermal stress on kuruma prawn (Penaeus japonicus) juveniles

Growing concerns have emerged over the combined effects of multiple stressors on ecosystems. Empirical evidence shows that the sensitivity of aquatic invertebrates to insecticides varies under thermally fluctuating conditions. Additionally, field surveys in estuarine areas of western Japan confirmed the presence of juvenile kuruma prawns (Penaeus japonicus) carrying the white spot syndrome virus (WSSV). Given the potential of co-exposure to multiple stressors, we performed a combined exposure experiment using a full-factorial design with three stressors: WSSV infection (presence or absence: initial 2 h exposure), fipronil (insecticide) exposure (0 or 0.1 μg/L: 14 d exposure), and temperature (20, 25, or 30 °C). We observed the highest mortality (75 %) in the WSSV + Fipronil treatment at 30 °C, with the associated specimens showing significant changes in the internal load of WSSV and concentrations of fipronil and its metabolite, fipronil sulfone. Severe perturbations of metabolites associated with increased energy expenditure and fatty acid utilization have been identified as potential factors underlying lethality in juvenile kuruma prawns. The results demonstrate that WSSV infection increases the susceptibility of thermally stressed juvenile kuruma prawns to fipronil. Therefore, further studies are required to determine the combined effects of multiple stressors in environmentally relevant scenarios on juvenile kuruma prawns as well as in estuarine ecosystems.

Proviral and antiviral roles of phosphofructokinase family of glycolytic enzymes in TBSV replication

Positive-strand RNA viruses build viral replication organelles (VROs) with the help of co-opted host factors. The biogenesis of the membranous VROs requires major metabolic changes in infected cells. Previous studies showed that tomato bushy stunt virus (TBSV) hijacks several glycolytic enzymes to produce ATP locally within VROs. In this work, we demonstrate that the yeast Pfk2p phosphofructokinase, which performs a rate-limiting and highly regulated step in glycolysis, interacts with the TBSV p33 replication protein. Deletion of PFK2 reduced TBSV replication in yeast, suggesting proviral role for Pfk2p. TBSV also co-opted two plant phosphofructokinases, which supported viral replication and ATP production within VROs, thus acting as proviral factors. Three other phosphofructokinases inhibited TBSV replication and they reduced ATP production within VROs, thus functioning as antiviral factors. Altogether, different phosphofructokinases have proviral or antiviral roles. This suggests on-going arms race between tombusviruses and their hosts to control glycolysis pathway in infected cells.

Transcriptome analysis of Scylla paramamosain hepatopancreas response to mud crab dicistrovirus-1 infection

Scylla paramamosain, an economically significant crab, is widely cultivated worldwide. In recent years, S. paramamosain has faced a serious threat from viral diseases due to the expansion of culture scale and increased culture density. Among these, mud crab dicistrovirus-1 (MCDV-1) stands out as highly pathogenic, presenting substantial challenges to the healthy development of mud crab aquaculture. Therefore, a comprehensive understanding of the mud crab immune response to MCDV-1 infection is imperative for devising effective disease prevention strategies. In this study, transcriptomic analyses were conducted on the hepatopancreas of mud crabs infected with MCDV-1. The findings revealed a total of 5139 differentially expressed genes (DEGs) between healthy and MCDV-1 infected mud crabs, including 3327 upregulated and 1812 downregulated DEGs. Further analysis showed that mud crabs resist MCDV-1 infection by activating humoral immune-related pathways, including the MAPK signaling pathway, MAPK signaling pathway-fly, and Toll and Imd signaling pathway. In contrast, MCDV-1 infection triggers host metabolic disorders. Several immune-related vitamin metabolism pathways (ascorbate and aldarate metabolism, retinol metabolism, and nicotinate and nicotinamide metabolism) were significantly inhibited, which may create favorable conditions for the virus's self-replication. Notably, endocytosis emerged as significantly upregulated both in GO terms and KEGG pathways, with several viral endocytosis-related pathways showing significant activation. PPI network analysis identified 9 hub genes associated with viral endocytosis within the endocytosis. Subsequent GeneMANIA analysis confirmed the association of these hub genes with viral endocytosis. Both transcriptome data and qPCR analysis revealed a significant upregulation of these hub genes post MCDV-1 infection, suggesting MCDV-1 may use viral endocytosis to enter cells and facilitate replication. This study represents the first comprehensive report on the transcriptomic profile of mud crab hepatopancreas response to MCDV-1 infection. Future investigations should focus on elucidating the mechanisms through which MCDV-1 enters cells via endocytosis, as this may holds critical implications for the development of vaccine targets.

TIPE1 limits virus replication by disrupting PKM2/ HIF-1α/ glycolysis feedback loop

OBJECTIVE

Virus infection is a major threat to human health and remains a significant cause of death to date. Macrophages are important innate immune cells that exhibit indispensable roles in controlling virus replication. It was recently reported that metabolic adaption determines the functional state of macrophages. Thus, to further unravel the crucial factors involving in metabolic adaption of macrophages might provide the potential candidates for optimizing their anti-viral capabilities.

METHODS

RT-PCR, Western blotting, virus plaque assay and HE were used to evaluate the viral load in virus-infected Tipe1M-KO and Tipe1f/f mice or cultured macrophages. RNA sequencing were performed with Tipe1M-KOor Tipe1f/f BMDMs upon virus infection. Extracellular acidification rate (ECAR) was applied for analyzing glycolysis rate in virus-infected BMDMs. Co-immunoprecipitation (Co-IP) assay and LC-MS/MS were used to determine the potential interacting proteins of TIPE1.

RESULTS

TIPE1 level was significantly reduced in BMDMs infected with either RNA viruses or DNA virus. Deficiency of Tipe1 in macrophages increased viral load and aggravated tissue damage. Mechanistically, TIPE1 suppressed the glycolytic capacity of macrophages through interacting with PKM2 and promoting its ubiquitination degradation, which in turn decreased HIF1α transcription and viral replication in macrophages.

CONCLUSIONS

TIPE1 functions as a novel regulator for metabolic reprogramming and virus infection in macrophages.

Matrix Protein of Vesicular Stomatitis Virus Targets the Mitochondria, Reprograms Glucose Metabolism, and Sensitizes to 2-Deoxyglucose in Glioblastoma

A potential therapeutic approach for cancer treatment is target oxidative phosphorylation and glycolysis simultaneously. The matrix protein of vesicular stomatitis virus (VSV MP) can target the surface of mitochondria, causing morphological changes that may be associated with mitochondrial dysfunction and oxidative phosphorylation inhibition. Previous research has shown that mitochondrial abnormalities can direct glucose metabolism toward glycolysis. Thus, after treatment with VSV MP, glycolysis inhibition is necessary to completely block glucose metabolism and eradicate cancer. Here, to inhibit glycolysis, the 2-deoxy-D-glucose (2-DG), a synthetic glucose analog was used to combine with VSV MP to treat cancer. This study aims to determine how VSV MP affects the glucose bioenergetic metabolism of cancer cells and to evaluate the synergistic effect of 2-DG when combined with VSV. Our results indicated that in U87 and C6 glioblastoma cell lines, VSV MP caused mitochondrial membrane potential loss, cytochrome c release, and glucose bioenergetics metabolism reprogramming. When combined with 2-DG, VSV MP synergistically aggravated cell viability, apoptosis, and G2/M phase arrest. Meanwhile, the combination therapy exacerbated ATP depletion, activated AMPK, and inhibited mammalian target of rapamycin signaling pathways. In addition, 2-DG treatment alone induced autophagy in glioblastoma cells; however, VSV MP inhibited the autophagy induced by 2-DG in combined treatment and finally contributed to the enhanced cytotoxic effect of the combination strategy in U87 and C6 cancer cells. In the orthotopic U87 glioblastoma model and subcutaneous C6 glioblastoma model, the combined treatment led to significant tumor regression and prolonged survival. A potent therapeutic approach for treating glioblastoma may be found in the combination of VSV MP and glycolytic inhibitors.

The interaction between 20-hydroxyecdysone and AMPK through PI3K activation in Chinese mitten crab, Eriocheir sinensis

In crustaceans, the steroid hormone 20-hydroxyecdysone (20E) initiates molting, and the molting process is also regulated by energy metabolism. AMPK is an energy sensor and plays a critical role in systemic energy balance. Here, the regulatory mechanism in the interaction between 20E and AMPK was investigated in Chinese mitten crab, Eriocheir sinensis. The results showed that the 20E concentration and the mRNA expression levels of 20E receptors in hepatopancreas were down-regulated post AMPK activator (AICAR) treatment, and were up-regulated after AMPK inhibitor (Compound C) injection in crabs. Besides, the molt-inhibiting hormone (MIH) gene expression in eyestalk showed the opposite patterns in response to the AICAR and Compound C treatment, respectively. Further investigation found that there was a significant reduction in 20E concentration post PI3K inhibitor (LY294002) treatment, and the phosphorylation level of PI3K was increased in hepatopancreas after AMPK inhibitor injection. On the other hand, the positive regulation of PI3K-mediated activation of AMPK was also observed, the phosphorylation levels of AMPKα, AMPKβ and PI3K in hepatopancreas were significantly increased post 20E injection. In addition, the phosphorylation levels of AMPKα and AMPKβ induced by 20E were decreased after the injection of PI3K inhibitor. Taken together, these results suggest that the regulatory cross-talk between 20E and AMPK is likely to act through PI3K pathway in E. sinensis, which appeared to be helpful for a better understanding in molting regulation.

WSSV early protein WSSV004 enhances viral replication by suppressing LDH activity

White spot syndrome virus (WSSV) is known to upregulate glycolysis to supply biomolecules and energy for the virus's replication. At the viral genome replication stage, lactate dehydrogenase (LDH), a glycolytic enzyme, shows increased activity without any increase in expression. In the present study, yeast 2-hybrid screening was used to identify WSSV proteins that interacted with LvLDH isoform 1 and 2, and these included the WSSV early protein WSSV004. The interaction between WSSV004 and LvLDH1/2 was confirmed by co-immunoprecipitation. Immunofluorescence showed that WSSV004 co-localized with LvLDH1/2 in the cytoplasm. dsRNA silencing experiments showed that WSSV004 was crucial for WSSV replication. However, although WSSV004 silencing led to the suppression of total LvLDH gene expression during the viral late stage, there was nevertheless a significant increase in LvLDH activity at this time. We also used affinity purification-mass spectrometry to identify cellular proteins that interact with WSSV004, and found a total of 108 host proteins and 3 WSSV proteins with which it potentially interacts. Bioinformatics analysis revealed that WSSV004 and its interacting proteins might be responsible for various biological pathways during infection, including vesicular transport machinery and RNA-related functions. Collectively, our study suggests that WSSV004 serves as a multifunctional modulator to facilitate WSSV replication.

Bombyx mori triose-phosphate transporter protein inhibits Bombyx mori nucleopolyhedrovirus infection by reducing the cell glycolysis pathway

Bombyx mori triose-phosphate transporter protein (BmTPT) is a member of the solute carrier (SLC) family. Its main function is to transport triose phosphate between intracellular and extracellular. In this study, BmTPT was cloned and characterised from the fat body of the silkworm Bombyx mori, resulting in an open reading frame (ORF) with a full length of 936 bp, which can encode 311 amino acid residues and has eight transmembrane structural domains. BmTPT was distributed throughout the cell and deposited the most in the nucleus, and is expressed in all tissues of Bombyx mori. Bombyx mori nucleopolyhedrovirus (BmNPV) infection significantly up-regulated BmTPT expression in immune tissue fat bodies. In addition, overexpression of BmTPT significantly inhibited BmNPV infection and markedly reduced the expression of enzymes related to the cellular glycolytic pathway; on the contrary, down-regulation of BmTPT expression by RNA interference resulted in robust replication of BmNPV and a significant increase in the expression of enzymes related to the cellular glycolytic pathway. This is the first report that BmTPT has antiviral effect in silkworm, and also could result in a lack of energy and raw materials for BmNPV replication and infection through down-regulation of the cellular glycolytic pathway.

HIF-1-mediated regulation of LDH gene unravels key insights into MCDV-1 pathogenesis in mud crabs Scylla paramamosain

Hypoxia-inducible factors -1 (HIF-1) is a crucial transcription factor that regulates the expression of glycolytic genes. Our previous study proved that the Mud crab dicistrovirus-1 (MCDV-1) can induce aerobic glycolysis that favors viral replication in mud crab Scylla paramamosain. However, the role of HIF-1 on key glycolytic genes during the MCDV-1 infection has not been examined. In this study, the intricate interplay between HIF-1 and the key glycolysis enzyme, lactate dehydrogenase (LDH), was investigated after MCDV-1 infection. The expression of LDH was significant increased after MCDV-1 infection. Additionally, the expression of HIF-1α was upregulated following MCDV-1 infection, potentially attributed to the downregulation of prolyl hydroxylase domains 2 expression. Subsequent examination of the SpLDH promoter identified the presence of hypoxia response elements (HREs), serving as binding sites for HIF-1α. Intriguingly, experimental evidence demonstrated that SpHIF-1α actively promotes SpLDH transcription through these HREs. To further elucidate the functional significance of SpHIF-1α, targeted silencing was employed, resulting in a substantial reduction in SpLDH expression, activity, and lactate concentrations in MCDV-1-infected mud crabs. Notably, SpHIF-1α-silenced mud crabs exhibited higher survival rates and lower viral loads in hepatopancreas tissues following MCDV-1 infection. These results highlight the critical role of SpHIF-1α in MCDV-1 pathogenesis by regulating LDH gene dynamics, providing valuable insights into the molecular mechanisms underlying the virus-host interaction.

Integrated Metabolomic and transcriptomic analyses reveal deoxycholic acid promotes transmissible gastroenteritis virus infection by inhibiting phosphorylation of NF-κB and STAT3

BACKGROUND

Acute diarrhea, dehydration and death in piglets are all symptoms of transmissible gastroenteritis virus (TGEV), which results in significant financial losses in the pig industry. It is important to understand the pathogenesis and identify new antiviral targets by revealing the metabolic interactions between TGEV and host cells.

RESULTS

We performed metabolomic and transcriptomic analyses of swine testicular cells infected with TGEV. A total of 1339 differential metabolites and 206 differentially expressed genes were detected post TEGV infection. The differentially expressed genes were significantly enriched in the HIF-1 signaling pathway and PI3K-Akt signaling. Integrated analysis of differentially expressed genes and differential metabolites indicated that they were significantly enriched in the metabolic processes such as nucleotide metabolism, biosynthesis of cofactors and purine metabolism. In addition, the results showed that most of the detected metabolites involved in the bile secretion was downregulated during TGEV infection. Furthermore, exogenous addition of key metabolite deoxycholic acid (DCA) significantly enhanced TGEV replication by NF-κB and STAT3 signal pathways.

CONCLUSIONS

We identified a significant metabolite, DCA, related to TGEV replication. It added TGEV replication in host cells by inhibiting phosphorylation of NF-κB and STAT3. This study provided novel insights into the metabolomic and transcriptomic alterations related to TGEV infection and revealed potential molecular and metabolic targets for the regulation of TGEV infection.

Targeting the Warburg effect: A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival, with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation, even under sufficient oxygen supply condition. This metabolic alteration, known as the Warburg effect, serves as a significant indicator of malignant tumor transformation. The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells. Key enzymes involved in this process include glucose transporters (GLUTs), HKs, PFKs, LDHs, and PKM2. Moreover, the expression of transcriptional regulatory factors and proteins, such as FOXM1, p53, NF-κB, HIF1α, and c-Myc, can also influence cancer progression. Furthermore, lncRNAs, miRNAs, and circular RNAs play a vital role in directly regulating the Warburg effect. Additionally, gene mutations, tumor microenvironment remodeling, and immune system interactions are closely associated with the Warburg effect. Notably, the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment. This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

Shrimp SIRT4 promotes white spot syndrome virus replication

In WSSV pathogenesis, the molecular mechanisms and the key host factors that regulate the viral replication and morphogenesis remain unclear. However, like most viruses, WSSV is known to induce metabolic reprogramming in several metabolic pathways including the host glutamine metabolism, and several recent reports have suggested that the sirtuins SIRT3, SIRT4, and SIRT5, which belong to a family of NAD+-dependent deacetylases, play an important role in this regulation. Here we focus on characterizing LvSIRT4 from Litopenaeus vannamei and investigate its role in regulating glutamine dehydrogenase (GDH), an important enzyme that promotes glutaminolysis and viral replication. We found that LvSIRT4 silencing led to significant decreases in both WSSV gene expression and the number of viral genome copies. Conversely, overexpression of LvSIRT4 led to significant increases in the expression of WSSV genes and the WSSV genome copy number. Immunostaining in Sf9 insect cells confirmed the presence of LvSIRT4 in the mitochondria and the co-localization of LvSIRT4 and LvGDH in the same cellular locations. In vivo gene silencing of LvSIRT4 significantly reduced the gene expression of LvGDH whereas LvSIRT4 overexpression had no effect. However, neither silencing nor overexpression had any effect on the protein expression levels of LvGDH. Lastly, although GDH activity in uninfected shrimp was unchanged, the GDH enzyme activity in WSSV-infected shrimp was significantly increased after both LvSIRT4 silencing and overexpression. This suggests that although there may be no direct regulation, LvSIRT4 might still be able to indirectly regulate LvGDH via the mediation of one or more WSSV proteins that have yet to be identified.

Silencing of crustacean hyperglycemic hormone gene expression reveals the characteristic energy and metabolic changes in the gills and epidermis of crayfish Procambarus clarkii

The crustacean hyperglycemic hormone (CHH) is a multifaceted neuropeptide instrumental in regulating carbohydrate and lipid metabolism, reproduction, osmoregulation, molting, and metamorphosis. Despite its significance, there is a dearth of research on its metabolic impact on the gills and epidermis-key organs in osmoregulation and molting processes. This study employed CHH dsRNA injections to silence CHH gene expression in Procambarus clarkii, followed by a metabolomic analysis of the gills and epidermis using nuclear magnetic resonance spectroscopy. Metabolic profiling through principal component analysis revealed the most pronounced changes at 24 h post-injection (hpi) in the epidermis and at 48 hpi in the gills. At 24 hpi, the epidermis exhibited significant modulation in 25 enrichment sets and 20 KEGG pathways, while at 48 hpi, 5 metabolite sets and 6 KEGG pathways were prominently regulated. Notably, pathways associated with amino acid metabolism, carbohydrate metabolism, and cofactor and vitamin metabolism were affected. A marked decrease in glucose and other carbohydrates suggested a compromised carbohydrate supply, whereas increased levels of citrate cycle intermediates implied a potential boost in energy provision. The silencing of CHH gene expression hampered the carbohydrate supply, which was possibly the main energy derived substrates. Conversely, the gills displayed significant alterations in 15 metabolite sets and 16 KEGG pathways at 48 hpi, with no significant changes at 24 hpi. These changes encompassed amino acid, carbohydrate, and lipid metabolism pathways. The decline in TCA cycle intermediates pointed to a potential downregulation of the cycle, whereas a decrease in ketone bodies indicated a shift towards lipid metabolism for energy production. Additionally, increased levels of nicotinate, nicotinamide, and quinolinate were observed in both organs. Overall, CHH's impact on the epidermis was prominent at 24 hpi and diminished thereafter, whereas its influence on metabolism in gills was delayed but intensified at 48 hpi. This differential CHH effect between gills and epidermis in P. clarkii provides new insights into the organ-specific regulatory mechanisms of CHH on energy metabolism and osmoregulation, warranting further comparative studies to elucidate the distinct roles of CHH in these organs.

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.

SPI1 involvement in malignant melanoma pathogenesis by regulation of HK2 through the AKT1/mTOR pathway

Spi-1 proto-oncogene (SPI1) plays a vital role in carcinogenesis. Our work aimed to investigate the potential regulatory mechanism of SPI1 in melanoma. The mRNA and protein levels were measured via qRT-PCR and Western blotting. Cell viability was assessed by CCK-8 assay. The target relationship between SPI1 and hexokinase 2 (HK2) was determined using dual-luciferase reporter detection. ChIP was conducted to confirm the targeted relationship between SPI1 and the HK2 promoter. Immunohistochemistry analysis was conducted to measure the positive cell number of SPI1 and HK2 in melanoma tissues. The cell migration abilities were determined using a wound healing assay. Glucose consumption, pyruvate dehydrogenase activity, lactate production and ATP levels were measured to assess glycolysis. SPI1 transcription in melanoma cells and tissues was dramatically higher than that in adjacent normal tissues and epidermal melanocyte HEMa-LP, respectively. Knockdown of SPI1 restrained cell viability, metastasis and glycolysis in melanoma cells. SPI1 directly targeted HK2, and knockdown of SPI1 repressed HK2 expression. Overexpression of HK2 weakened the inhibitory effects of SPI1 knockdown on the viability, metastasis and glycolysis of melanoma cells. The serine-threonine kinase 1 (AKT1)/mammalian target of rapamycin (mTOR) axis is involved in melanoma progression. SPI1 knockdown restrained melanoma cell proliferation, metastasis and glycolysis by regulating the AKT1/mTOR pathway.

Integrated application of transcriptomics and metabolomics provides insights into acute hepatopancreatic necrosis disease resistance of Pacific white shrimp Litopenaeus vannamei

Acute hepatopancreatic necrosis disease (AHPND) has caused a huge economic loss to shrimp aquaculture. Vibrio parahaemolyticus (VpAHPND) is regarded as a major causative agent of AHPND in the Pacific white shrimp Litopenaeus vannamei. However, knowledge about how shrimp resist to AHPND is very limited. In order to learn the molecular mechanisms underlying AHPND resistance of shrimp, comparison between disease-resistant family and susceptible family of L. vannamei were performed at transcriptional and metabolic levels. Integrated analysis of transcriptomics and metabolomics on hepatopancreas of shrimp, the target tissue of VpAHPND, showed that significant differences existed between resistant family and susceptible family of shrimp. The susceptible family showed higher level of glycolysis, serine-glycine metabolism, purine and pyrimidine metabolism, but lower level of betaine-homocysteine metabolism in the hepatopancreas in comparison with the resistant family without VpAHPND infection. Curiously, VpAHPND infection induced up-regulation of glycolysis, serine-glycine metabolism, purine metabolism, pyrimidine metabolism, and pentose phosphate pathway, and down-regulation of betaine-homocysteine metabolism in resistant family. In addition, arachidonic acid metabolism and some immune pathways, like NF-κB and cAMP pathways, were up-regulated in the resistant family after VpAHPND infection. In contrast, amino acid catabolism boosted via PEPCK-mediated TCA cycle flux was activated in the susceptible family after VpAHPND infection. These differences in transcriptome and metabolome between resistant family and susceptible family might contribute to the resistance of shrimp to bacteria. IMPORTANCE Vibrio parahaemolyticus (VpAHPND) is a major aquatic pathogen causing acute hepatopancreatic necrosis disease (AHPND) and leads to a huge economic loss to shrimp aquaculture. Despite the recent development of controlling culture environment, disease resistant broodstock breeding is still a sustainable approach for aquatic disease control. Metabolic changes occurred during VpAHPND infection, but knowledge about the metabolism in resistance to AHPND is very limited. Integrated analysis of transcriptome and metabolome revealed the basal metabolic differences exhibited between disease-resistant and susceptible shrimp. Amino acid catabolism might contribute to the pathogenesis of VpAHPND and arachidonic acid metabolism might be responsible for the resistance phenotype. This study will help to enlighten the metabolic and molecular mechanisms underlying shrimp resistance to AHPND. Also, the key genes and metabolites of amino acid and arachidonic acid pathway identified in this study will be applied for disease resistance improvement in the shrimp culture industry.

Resilience and probiotic interventions to prevent and recover from shrimp gut dysbiosis

To counter the recurrent outbreaks of bacterial (acute hepatopancreatic necrosis disease; AHPND) and viral (white spot disease; WSD) shrimp diseases, which still remain a threat to the global industry, shrimp gut microbiota research has been gaining more attention in recent years, and the use of probiotics in aquaculture has had promising results in improving shrimp gut health and immunity. In this review based on our studies on AHPND and WSD, we summarize our current understanding of the shrimp gastrointestinal tract and the role of the microbiota in disease, as well as effects of probiotics. We focus particularly on the concept of microbiota resilience, and consider strategies that can be used to restore shrimp gut health by probiotic intervention at a crucial time during gut microbiota dysbiosis. Based on the available scientific evidence, we argue that the use of probiotics potentially has an important role in controlling disease in shrimp aquaculture.

Circular RNAs as the pivotal regulators of epithelial-mesenchymal transition in gastrointestinal tumor cells

Gastrointestinal (GI) cancers, as the most common human malignancies are always considered one of the most important health challenges in the world. Late diagnosis in advanced tumor stages is one of the main reasons for the high mortality rate and treatment failure in these patients. Therefore, investigating the molecular pathways involved in GI tumor progression is required to introduce the efficient markers for the early tumor diagnosis. Epithelial-mesenchymal transition (EMT) is one of the main cellular mechanisms involved in the GI tumor metastasis. Non-coding RNAs (ncRNAs) are one of the main regulatory factors in EMT process. Circular RNAs (circRNAs) are a group of covalently closed loop ncRNAs that have higher stability in body fluids compared with other ncRNAs. Considering the importance of circRNAs in regulation of EMT process, in the present review we discussed the role of circRNAs in EMT process during GI tumor invasion. It has been reported that circRNAs mainly affect the EMT process through the regulation of EMT-specific transcription factors and signaling pathways such as WNT, PI3K/AKT, TGF-β, and MAPK. This review can be an effective step in introducing a circRNA/EMT based diagnostic panel marker for the early tumor detection among GI cancer patients.

WSSV exploits AMPK to activate mTORC2 signaling for proliferation by enhancing aerobic glycolysis

AMPK plays significant roles in the modulation of metabolic reprogramming and viral infection. However, the detailed mechanism by which AMPK affects viral infection is unclear. The present study aims to determine how AMPK influences white spot syndrome virus (WSSV) infection in shrimp (Marsupenaeus japonicus). Here, we find that AMPK expression and phosphorylation are significantly upregulated in WSSV-infected shrimp. WSSV replication decreases remarkably after knockdown of Ampkα and the shrimp survival rate of AMPK-inhibitor injection shrimp increases significantly, suggesting that AMPK is beneficial for WSSV proliferation. Mechanistically, WSSV infection increases intracellular Ca2+ level, and activates CaMKK, which result in AMPK phosphorylation and partial nuclear translocation. AMPK directly activates mTORC2-AKT signaling pathway to phosphorylate key enzymes of glycolysis in the cytosol and promotes expression of Hif1α to mediate transcription of key glycolytic enzyme genes, both of which lead to increased glycolysis to provide energy for WSSV proliferation. Our findings reveal a novel mechanism by which WSSV exploits the host CaMKK-AMPK-mTORC2 pathway for its proliferation, and suggest that AMPK might be a target for WSSV control in shrimp aquaculture.

Role of asparagine biosynthesis pathway in Siniperca chuatsi rhabdovirus proliferation

Viruses are non-living organisms that rely on host cellular metabolism to complete their life cycle. Siniperca chuatsi rhabdovirus (SCRV) has caused huge economic losses to the Chinese perch (Siniperca chuatsi) industry worldwide. SCRV replication is dependent on the cellular glutamine metabolism, while aspartate metabolism plays an important role in viral proliferation in glutamine deficiency. Herein, we investigated roles of asparagine metabolism in SCRV proliferation. Results showed that SCRV infection upregulated the expression of key enzymes in the aspartate metabolic pathway in CPB cells. And the key enzymes of malate-aspartic acid shuttle pathway upregulated during the virus invasion phase, and key enzymes of the asparagine biosynthesis pathway upregulated during the viral replication and release phase. When asparagine was added to the depleted medium, the SCRV copy number restored to 90% of those in replete medium, showing that asparagine and glutamine completely rescue the replication of SCRV. Moreover, inhibition of the aspartate- malate shuttle pathway and knockdown of the expression of key enzymes in the asparagine biosynthesis pathway significantly reduced SCRV production, indicating that the aspartic acid metabolic pathway was required to the replication and proliferation of SCRV. Above results provided references for elucidating pathogenic mechanism of SCRV by regulation of aspartate metabolism.

Transcriptome Analysis on Hepatopancreas Reveals the Metabolic Dysregulation Caused by Vibrio parahaemolyticus Infection in Litopenaeus vannamei

Acute hepatopancreas necrosis disease (AHPND) has caused massive deaths of shrimp and has led to huge economic losses in aquaculture. Vibrio parahaemolyticus (VPAHPND) carrying a plasmid encoding binary toxins homologous to the photorhabdus insect-related (Pir) toxins is one of the main pathogens causing this disease. Previous studies have reported many immune-related genes of shrimp in response to this pathogenic bacteria. However, few studies have so far focused on the metabolic changes in Litopenaeus vannamei upon VPAHPND infection. In the present study, comparative transcriptomic analysis was performed on the hepatopancreas of shrimp at different times during VPAHPND infection. Functional analyses on the differentially expressed genes (DEGs) during infection showed that pathways related to glucose, energy and amino acid metabolism, as well as nucleic acid synthesis, were obviously changed in the hepatopancreas after VPAHPND infection. Additionally, three signaling pathways, which could regulate metabolic processes, including HIF-1 signaling pathway, PI3K-Akt signaling pathway and NF-KappaB signaling pathway, also changed significantly. Collectively, these data reveal a close relationship between host metabolism processes and Vibrio infection. The information will enrich our understanding of the interaction mechanism between the shrimp and Vibrio.

Applying genetic technologies to combat infectious diseases in aquaculture

Disease and parasitism cause major welfare, environmental and economic concerns for global aquaculture. In this review, we examine the status and potential of technologies that exploit genetic variation in host resistance to tackle this problem. We argue that there is an urgent need to improve understanding of the genetic mechanisms involved, leading to the development of tools that can be applied to boost host resistance and reduce the disease burden. We draw on two pressing global disease problems as case studies-sea lice infestations in salmonids and white spot syndrome in shrimp. We review how the latest genetic technologies can be capitalised upon to determine the mechanisms underlying inter- and intra-species variation in pathogen/parasite resistance, and how the derived knowledge could be applied to boost disease resistance using selective breeding, gene editing and/or with targeted feed treatments and vaccines. Gene editing brings novel opportunities, but also implementation and dissemination challenges, and necessitates new protocols to integrate the technology into aquaculture breeding programmes. There is also an ongoing need to minimise risks of disease agents evolving to overcome genetic improvements to host resistance, and insights from epidemiological and evolutionary models of pathogen infestation in wild and cultured host populations are explored. Ethical issues around the different approaches for achieving genetic resistance are discussed. Application of genetic technologies and approaches has potential to improve fundamental knowledge of mechanisms affecting genetic resistance and provide effective pathways for implementation that could lead to more resistant aquaculture stocks, transforming global aquaculture.

A review on molecular detection techniques of white spot syndrome virus: Perspectives of problems and solutions in shrimp farming

This review aims to provide an update on the current scientific understanding of various aspects of White Spot Syndrome Virus (WSSV) formation, diagnostic procedures, transmission, ecological effects, pathophysiology and management strategies. In terms of production and financial benefits, the WSSV has been the most virulent in shrimp and several other crustacean sectors around the globe. It spreads vertically from diseased broodstock to post-larvae and horizontally by cannibalism, invertebrate vectors, freshwater and sediments. In the transfer of white spot disease (WSD) in newly stocked ponds, the survivability of WSSV in sediment is the most important variable. In typical cultural conditions, it is a highly infectious pathogen capable of inflicting total death within 3-10 days after an outbreak. Some of the current biosecurity strategies used to keep diseases out of shrimp ponds such as pond water disinfection, quarantine of new stocks before stocking and broader usage of specific pathogen-free shrimp. The sequencing and characterisation of various WSSV strains have provided details about pathogen biology, pathogenicity and disease. To develop successful control methods, knowledge of these characteristics is essential. In several shrimp-producing countries in Asia and the Americas, the infections produced by the WSSV have had disastrous socio-economic consequences. As a result of international trade or migration of diseased species, the World Animal Health Organization recognised several illnesses as posing a substantial hazard to farmed shrimp. WSD is receiving much scientific research due to the potential economic effects of the virus. Research is now being done to understand better the molecular biology and pathophysiology of WSSV, as well as how to treat and prevent the virus. However, further study should be conducted in countries with more resilient host species to understand their role in mitigating disease impacts since these revelations may aid in developing a WSD treatment.

Oncolytic Avian Reovirus σA-Modulated Upregulation of the HIF-1α/C-myc/glut1 Pathway to Produce More Energy in Different Cancer Cell Lines Benefiting Virus Replication

Our previous reports proved that the structural protein σA of avian reovirus (ARV) is an energy activator which can regulate cellular metabolism that is essential for virus replication. This study has further demonstrated that the ARV protein σA is able to upregulate the HIF-1α/myc/glut1 pathway in three cancer cell lines (A549, B16-F10, and HeLa) to alter the metabolic pathway of host cells. Quantitative real-time RT-PCR and Western blotting results have revealed that σA protein could enhance both mRNA and the protein levels of HIF-1α, c-myc, and glut1 in these cancer cell lines. In this work, ATeam immunofluorescence staining was used to reveal that knockdown of HIF-1α, c-myc, and glut1 by shRNAs decreased cellular ATP levels. Our data reveal that the ARV σA protein can downregulate lactate fermentation and upregulate glutaminolysis. The σA protein upregulates glutaminase, which converts glutamate into the TCA cycle intermediate α-ketoglutarate, activating the TCA cycle. In the lactate fermentation pathway, ARV σA protein suppresses lactate dehydrogenase A (LDHA), implying the Warburg effect does not occur in these cancer cell lines. This study provides a novel finding revealing that ARV σA protein upregulates glycolysis and glutaminolysis to produce energy using the HIF-1α/c-myc/glut1 pathway to benefit virus replication in these cancer cell lines.

Transcriptome analysis of Pacific white shrimp (Liptopenaeus vannamei) after exposure to recombinant Vibrio parahaemolyticus PirA and PirB proteins

Vibrio parahaemolyticus is a Gram-negative bacterium commonly found in marine and estuarine environments and is endemic among the global shrimp aquaculture industry. V. parahaemolyticus proteins PirA and PirB have been determined to be major virulence factors that contribute significantly to the development of acute hepatopancreatic necrosis disease. Our previous work had demonstrated the lethality of recombinant PirA and PirB proteins to Pacific white shrimp (Liptopenaeus vannamei). To understand the host response to these proteins, recombinant PirA and PirB proteins were administered using a reverse gavage method and individual shrimp were then sampled over time. Shrimp hepatopancreas libraries were generated and RNA sequencing was performed on the control and recombinant PirA/B-treated samples. Differentially expressed genes were identified among the assayed time points. Differentially expressed genes that were co-expressed at the later time points (2-, 4- and 6-h) were also identified and gene associations were established to predict functional physiological networks. Our analysis reveals that the recombinant PirA and PirB proteins have likely initiated an early host response involving several cell survival signaling and innate immune processes.

White spot syndrome virus directly activates mTORC1 signaling to facilitate its replication via polymeric immunoglobulin receptor-mediated infection in shrimp

Previous studies have shown that the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway has antiviral functions or is beneficial for viral replication, however, the detail mechanisms by which mTORC1 enhances viral infection remain unclear. Here, we found that proliferation of white spot syndrome virus (WSSV) was decreased after knockdown of mTor (mechanistic target of rapamycin) or injection inhibitor of mTORC1, rapamycin, in Marsupenaeus japonicus, which suggests that mTORC1 is utilized by WSSV for its replication in shrimp. Mechanistically, WSSV infects shrimp by binding to its receptor, polymeric immunoglobulin receptor (pIgR), and induces the interaction of its intracellular domain with Calmodulin. Calmodulin then promotes the activation of protein kinase B (AKT) by interaction with the pleckstrin homology (PH) domain of AKT. Activated AKT phosphorylates mTOR and results in the activation of the mTORC1 signaling pathway to promote its downstream effectors, ribosomal protein S6 kinase (S6Ks), for viral protein translation. Moreover, mTORC1 also phosphorylates eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), which will result in the separation of 4EBP1 from eukaryotic translation initiation factor 4E (eIF4E) for the translation of viral proteins in shrimp. Our data revealed a novel pathway for WSSV proliferation in shrimp and indicated that mTORC1 may represent a potential clinical target for WSSV control in shrimp aquaculture.

White spot syndrome virus (WSSV) is the causative pathogen of white spot disease (WSD) and represents the most destructive viral disease of shrimp. The virus has evolved various strategies to escape from host defenses or exploit host biological pathways for its reproduction. Studies on viral immune-escape mechanisms can provide new strategies for disease prevention and control in shrimp aquaculture. Mechanistic target of rapamycin (mTOR) plays a central role in the regulation of cell growth and metabolism, which nucleates two distinct protein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) with diverse functions at different levels of the signaling pathway. mTORC1 is reported to be exploited by viruses in their reproduction. However, the detail mechanism remains unclear. In this study, we identified a new mechanism of mTOR being hijacked by WSSV in shrimp (Marsupenaeus japonicus). WSSV infects shrimp by its receptor, pIgR and induces the interaction of the intracellular domain of pIgR with Calmodulin. Calmodulin subsequently promotes the activation of AKT by interaction with the pleckstrin homology domain of the kinase. Activated AKT phosphorylates mTOR and results in the activation of the mTORC1 signaling pathway to promote its downstream effectors, S6Ks, for viral protein synthesis. Moreover, mTORC1 also phosphorylates 4EBP1, which results in the separation of 4EBP1 from eIF4E for the translation of viral proteins in shrimp. Our study reveals a novel strategy for WSSV proliferation in shrimp and indicates that the components of mTORC1 may represent potential clinical targets for WSSV control in shrimp aquaculture.

Harsh intertidal environment enhances metabolism and immunity in oyster (Crassostrea gigas) spat

The Pacific oyster Crassostrea gigas is established in the marine intertidal zone, experiencing rapid and highly dynamic environmental changes throughout the tidal cycle. Depending on the bathymetry, oysters face oxygen deprivation, lack of nutrients, and high changes in temperature during alternation of the cycles of emersion/immersion. Here we showed that intertidal oysters at a bathymetry level of 3 and 5 m delayed by ten days the onset of mortality associated with Pacific Oyster Mortality Syndrome (POMS) as compared to subtidal oysters. Intertidal oysters presented a lower growth but similar energetic reserves to subtidal oysters but induced proteomic changes indicative of a boost in metabolism, inflammation, and innate immunity that may have improved their resistance during infection with the Ostreid herpes virus. Our work highlights that intertidal harsh environmental conditions modify host-pathogen interaction and improve oyster health. This study opens new perspectives on oyster farming for mitigation strategies based on tidal height.

Changes in metabolic profiling of whiteleg shrimp (Penaeus vannamei) under hypoxic stress

Hypoxia is a common concern in shrimp aquaculture, affecting growth and survival. Although recent studies have revealed important insights into hypoxia in shrimp and crustaceans, knowledge gaps remain regarding this stressor at the molecular level. In the present study, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics approach was employed to characterize the metabolic signatures and pathways underlying responses of Pacific white shrimp (Penaeus vannamei) to hypoxia and to identify associated candidate biomarkers. We compared metabolite profiles of shrimp haemolymph before (0 h) and after exposure to hypoxia (1 & 2 h). Dissolved oxygen levels were maintained above 85 % saturation in the control and before hypoxia, and 15 % saturation in the hypoxic stress treatment. Results showed 44 metabolites in shrimp haemolymph that were significantly different between before and after hypoxia exposure. These metabolites were energy-related metabolites (e.g., intermediates of citric acid cycle, lactic acid, alanine), fatty acids and amino acids. Pathway analysis revealed 17 pathways that were significantly affected by hypoxia. The changes in metabolites and pathways indicate a shift from aerobic to anaerobic metabolism, disturbance in amino acid metabolism, osmoregulation, oxidative damage and Warburg effect-like response caused by hypoxic stress. Among the altered metabolites, lactic acid was most different between before and after hypoxia exposure and had the highest accurate value for biomarker identification. Future investigations may validate this molecule as a stress biomarker in aquaculture. This study contributes to a better understanding of hypoxia in shrimp and crustaceans at the metabolic level and provides a base for future metabolomics investigations on hypoxia.

White Spot Syndrome Virus Triggers a Glycolytic Pathway in Shrimp Immune Cells (Hemocytes) to Benefit Its Replication

White spot syndrome virus (WSSV) is the causative agent of a shrimp disease that inflicts in huge economic losses in shrimp-farming industry. WSSV triggers aerobic glycolysis in shrimp immune cells (hemocytes), but how this virus regulates glycolytic enzymes or pathway is yet to be characterized. Therefore, mRNA levels and activity of four important glycolytic enzymes, Hexokinase (HK), Phosphofructokinase (PFK), Pyruvate kinase (PK), and Lactate dehydrogenase (LDH), were measured in WSSV-infected shrimp hemocytes. Gene expression of HK and PFK, but not LDH or PK, was increased at the viral genome replication stage (12 hpi); furthermore, activity of these enzymes, except HK, was concurrently increased. However, there was no increased enzyme activity at the viral late stage (24 hpi). In vivo dsRNA silencing and glycolysis disruption by 2-DG further confirmed the role of glycolysis in virus replication. Based on tracing studies using stable isotope labeled glucose, glycolysis was activated at the viral genome replication stage, but not at the viral late stage. This study demonstrated that WSSV enhanced glycolysis by activating glycolytic enzyme at the viral genome replication stage, providing energy and biomolecules for virus replication.

The Isolation and Full-Length Transcriptome Sequencing of a Novel Nidovirus and Response of Its Infection in Japanese Flounder (Paralichthys olivaceus)

A novel nidovirus, CSBV Bces-Po19, was isolated from the marine fish, Japanese flounder (Paralichthys olivaceus). The viral genome was 26,597 nucleotides long and shared 98.62% nucleotide identity with CSBV WHQSR4345. PacBio Sequel and Illumina sequencing were used to perform full-length transcriptome sequencing on CSBV Bces-Po19-sensitive (S) and -resistant (R) Japanese flounder. The results of negative staining revealed bacilliform and spherical virions. There were in total 1444 different genes between CSBV Bces-Po19 S and R groups, with 935 being up-regulated and 513 being down-regulated. Metabolism-, immune-, and RNA-related pathways were significantly enriched. Furthermore, CSBV Bces-Po19 infection induced alternative splicing (AS) events in Japanese flounder; the S group had a higher numbers of AS events (12,352) than the R group (11,452). The number of long non-coding RNA (lncRNA) in the S group, on the other hand, was significantly lower than in the R group. In addition to providing valuable information that sheds more light on CSBV Bces-Po19 infection, these research findings provide further clues for CSBV Bces-Po19 prevention and treatment.

Prior infection of Galleria mellonella with sublethal dose of Bt elicits immune priming responses but incurs metabolic changes

Invertebrate immune priming has attracted wide attention of biologists in recent years because it challenges core notions about the disparate nature of acquired and innate immunity. However, the metabolic switch and energetic cost during eliciting immune priming are poorly investigated issues, which could widen and deepen our understanding of the physiological mechanism of immune priming. In this study, using sublethal dose of Bacillus thuringiensis (Bt) as an elicitor, we detected typical immune priming responses in Galleria mellonella. We found that the intensity of immune priming is positively correlated with the levels of antimicrobial peptides and phagocytosis ability of hemocytes. Subsequently, we employed LC-MS/MS-based untargeted metabolomics techniques to analyze the metabolic changes in the fat body of G. mellonella larvae during immune priming. The results showed that there were 74 and 56 significantly altered metabolites in positive and negative ion mode, respectively, after Bt priming. Most of the differential metabolites were enriched in the following metabolic pathways: amino acid biosynthesis, carbon metabolism, aminoacyl-tRNA biosynthesis and ABC transporters. The energetic cost of immune priming was depicted mainly in the slow growth of body mass and decreased levels of sucrose, lactose, D-ribulose 1,5-bisphosphate, Glycerate-3P and isocitric acid, which are enriched in carbon metabolism and involved in energy production. Meanwhile, correlation and interaction network analysis showed negative correlations between carbohydrates and metabolites involved in amino acid biosynthesis, suggesting that amino acids acted as the main energy source and helped the organisms synthesize immune effectors to participate in the immune priming response. Our results pave the way for uncovering the physiological mechanism of insect immune priming and discovering novel targets for Bt insecticide.

Characterization of phosphofructokinase (PFK) from mud crab Scylla paramamosain and its role in mud crab dicistrovirus-1 proliferation

Phosphofructokinase (PFK), the key enzyme of glycolysis, can catalyze the irreversible transphosphorylation of fructose-6-phosphate forming fructose-1, 6-biphosphate. In the present study, a PFK gene from the mud crab Scylla paramamosain, named SpPFK, was cloned and characterized. The full length of SpPFK contained a 5'untranslated region (UTR) of 249 bp, an open reading frame of 2,859 bp, and a 3'UTR of 1,248 bp. The mRNA of SpPFK was highly expressed in the gill, followed by the hemocytes and muscle. The expression of SpPFK was significantly up-regulated after mud crab dicistrovirus-1 (MCDV-1) infection. Knocking down SpPFK in vivo by RNA interference significantly reduced the expression of lactate dehydrogenase after MCDV-1 infection. Furthermore, silencing of SpPFK in vivo increased the survival rate of mud crabs and decreased the MCDV-1 copies in the gill and hepatopancreas after MCDV-1 infection. All these results suggested that SpPFK could play an important role in the process of MCDV-1 proliferation in mud crab.

Singapore Grouper Iridovirus Induces Glucose Metabolism in Infected Cells by Activation of Mammalian Target of Rapamycin Signaling

Singapore grouper iridovirus (SGIV), a member of the Iridoviridae family, is an important marine cultured fish pathogen worldwide. Our previous studies have demonstrated that lipid metabolism was essential for SGIV entry and replication, but the roles of glucose metabolism during SGIV infection still remains largely unknown. In this study, we found that the transcription levels of key enzymes involved in glycolysis were regulated in varying degrees during SGIV infection based on the transcriptomic analysis. Quantitative PCR and western blot analysis also indicated that the expression of both glucose transporters (GLUT1 and GLUT2) and the enzymes of glucose metabolism (hexokinase 2, HK2 and pyruvate dehydrogenase complex, PDHX) were upregulated during SGIV infection in vivo or in vitro, suggesting that glycolysis might be involved in SGIV infection. Exogenous glucose supplementation promoted the expression of viral genes and infectious virion production, while glutamine had no effect on SGIV infection, indicating that glucose was required for SGIV replication. Consistently, pharmacological inhibition of glycolysis dramatically reduced the protein synthesis of SGIV major capsid protein (MCP) and infectious virion production, and promotion of glycolysis significantly increased SGIV infection. Furthermore, knockdown of HK2, PDHX, or GLUT1 by siRNA decreased the transcription and protein synthesis of SGIV MCP and suppressed viral replication, indicating that those enzymes exerted essential roles in SGIV replication. In addition, inhibition of mTOR activity in SGIV-infected cells effectively reduced the expression of glycolysis key enzymes, including HK2, PDHX, GLUT1, and GLUT2, and finally inhibited SGIV replication, suggesting that mTOR was involved in SGIV-induced glycolysis. Thus, our results not only provided new insights into the mechanism of how SGIV infection affects host cell glycolysis, but also contributed to further understanding of the iridovirus pathogenesis.

Protein phosphorylation in hemocytes of Fenneropenaeus chinensis in response to white spot syndrome virus infection

Protein phosphorylation and dephosphorylation are the most common and important regulatory mechanisms in signal transduction, which play a vital role in immune defense response. Our previous study has found the level of tyrosine phosphorylation was significantly changed in the hemocytes of Fenneropenaeus chinensis upon white spot syndrome virus (WSSV) infection. In order to explore the relationship between protein phosphorylation and WSSV infection, the quantitative phosphoproteomics was employed to identify differential phosphorylated proteins in hemocytes of F. chinensis before and after WSSV infection, and elucidate the role of key differential phosphorylated proteins in WSSV infection process. The results showed that a total of 147 differential phosphorylated proteins were identified in the hemocytes, including 64 phosphorylated proteins and 83 dephosphorylated proteins, which were mostly enriched in pyruvate metabolism, TCA cycle, glycolysis, and ribosomal biosynthesis. Functional analysis of differential phosphorylated proteins showed that they were involved in cell apoptosis, cell phagocytosis, cell metabolism and antiviral infection. A total of 236 differential phosphorylation sites were found, including 91 modified sites in the phosphorylation proteins and 145 modified sites in the dephosphorylation proteins. Motif analysis showed that these phosphorylation sites could activate mitogen-activated protein kinase, P70 S6 kinase and other kinases in hemocytes. Moveover, the phosphorylation levels of eukaryotic protein initiation factor 4E binding proteins and histone H3 were further determined by ELISA and Western blotting, which both exhibited a significant increase post WSSV infection and reach their peak levels at 6 and 12 h, respectively. Moreover, we found that lactate, a metabolite closely related to pyruvate metabolism, TCA cycle and glycolysis, was significantly increased in the hemocytes after WSSV infection. This study revealed the protein phosphorylation response in hemocytes of F. chinensis to WSSV infection, which help to clarify the response characteristics and virus resistance mechanism of hemocytes in F. chinensis, and also facilitate further understanding of the interaction between WSSV and shrimp hemocytes.

Myeloid ecotropic viral integration site-1 inhibition promotes apoptosis, suppresses proliferation of acute myeloid leukemia cells, accentuates the effects of anticancer drugs

To investigate the effects of myeloid ecotropic viral integration site-1 (MEIS1) on the proliferation and apoptosis of acute myeloid leukemia (AML) cells and the anticancer effects of the drug, we screened Kasumi-6, KG-1, and Kasumi-1 cells using quantitative reverse transcription polymerase chain reaction. Kasumi-6 and Kasumi-1 cells were subjected to human antigen R (HuR)-mediated interference (IV). Hexokinase 2 (HK2) expression and phosphorylation of protein kinase B (p-AKT) and mammalian target of rapamycin (p-mTOR) were observed with Western blotting. Cell proliferation was assessed using Cell Counting Kit-8, apoptosis was examined using Hoechst 33,258 staining, and glucose uptake was detected with a colorimetric biochemical assay kit. We found that, among the three cell lines tested, MEIS1 expression was highest in Kasumi-1 cells, which were therefore selected for subsequent experiments. Kasumi-1 cells receiving IV showed significantly decreased proliferation (p < 0.05) and increased apoptosis compared to the control group. Compared with the controls, IV significantly increased the expression of HK2, p-AKT, p-mTOR, multidrug resistance-associated protein 1 and P-glycoprotein (P < 0.05), but decreased glucose uptake. Treatment with adriamycin, daunorubicin and imatinib resulted in a progressive increase in inhibition of cell proliferation, with the IV group showing the highest inhibition rate among the three groups (P < 0.05). Thus, inhibition of MEIS1 activity promoted apoptosis, inhibited the proliferation of Kasumi-1 and Kasumi-6 cells, and increaseed the anticancer effect of the drugs, suggesting that inhibition of MEIS1 may be a potential strategy for the treatment of AML.

Integrated Analysis of mRNA-Seq and MiRNA-Seq Reveals the Molecular Mechanism of the Intestinal Immune Response in Marsupenaeus japonicus Under Decapod Iridescent Virus 1 Infection

The intestine is not only an important digestive organ but also an important immune organ for shrimp; it plays a key role in maintaining homeostasis. Decapod iridescent virus 1 (DIV1) is a new type of shrimp-lethal virus that has received extensive attention in recent years. To date, most studies of the shrimp intestinal immune response under viral infections have relied on single omics analyses; there is a lack of systematic multi-omics research. In the current study, intestinal mRNA-seq and microRNA (miRNA)-seq analyses of Marsupenaeus japonicus under DIV1 infection were performed. A total of 1,976 differentially expressed genes (DEGs) and 32 differentially expressed miRNAs (DEMs) were identified. Among them, 21 DEMs were negatively correlated with 194 DEGs from a total of 223 correlations. Functional annotation analysis revealed that M. japonicus can regulate glycosaminoglycan biosynthesis (chondroitin sulfate, dermatan sulfate, and keratan sulfate), vitamin metabolism (retinol metabolism and ascorbate and aldarate metabolism), immune pathway activation (Toll and IMD signaling pathways, Wnt signaling pathway, IL-17 signaling pathway, and Hippo signaling pathway), immunity enzyme activity promotion (triose-phosphate isomerase), antimicrobial peptide (AMP) expression, reactive oxygen species (ROS) production, and cell apoptosis through miRNAs to participate in the host’s antiviral immune response, while DIV1 can influence Warburg effect-related pathways (pyruvate metabolism, glycolysis/gluconeogenesis, and citrate cycle), glycosphingolipid biosynthesis-related pathways (glycosphingolipid biosynthesis—globo and isoglobo series and glycosphingolipid biosynthesis—lacto and neolacto series), and the tight junction and adhesion junction of the intestinal mucosal epithelium through the host’s miRNAs and mRNA to promote its own invasion and replication. These results indicate that intestinal miRNAs play important roles in the shrimp immune response against DIV1 infection. This study provides a basis for further study of the shrimp intestinal antiviral immune response and for the formulation of effective new strategies for the prevention and treatment of DIV1 infection.

Transcriptome profiling reveals the novel immunometabolism-related genes against WSSV infection from Fenneropenaeus merguiensis

The white spot syndrome virus (WSSV) has been considered a serious threat to shrimp aquaculture. Besides, the activation of cell metabolism as an immune reaction to the virus is now recognized as a piece of the pivotal puzzle of the antiviral responses. Hence, this study explores the relationship between metabolic gene expression and antiviral responses in shrimp using transcriptome analysis. The RNA-seq libraries of Fenneropenaeus merguensis hemocytes after WSSV challenge at early (6 hpi) and late (24 hpi) stages of infection were analyzed to identify differentially expressed genes (DEGs) that the WSSV subverted the expression. One-hundred-thirty-three DEGs that were expressed in response to WSSV infection at both stages were identified. Based on the GO annotation, they were related to innate immunity and metabolic pathway. The expression correlation between "full term" (NGS) and qRT-PCR of 16 representative DEGs is shown. Noticeably, the expression profiles of all the selected metabolic genes involved in glucose metabolism, lipid metabolism, amino acid metabolism, and nucleotide metabolism showed a specific correlation between NGS and qRT-PCR upon WSSV infection. Of these, we further characterized the function related to the WSSV response of glutamine: fructose-6-phosphate aminotransferase (FmGFAT), the rate-limiting enzyme of the hexosamine biosynthesis pathway, which was found to be up-regulated at the late stage of WSSV infection. Suppression of FmGFAT by RNA interference resulted in postponing the death of WSSV-infected shrimp and reduction of viral copy number. These results suggested that the FmGFAT is linked between metabolic change and WSSV responses in shrimp, where the virus-induced metabolic rewiring hijack biological compounds and/or energy sources to benefit the viral replication process.

PI3K/AKT/p53 pathway inhibits infectious spleen and kidney necrosis virus infection by regulating autophagy and immune responses

The PI3K/AKT/p53 signaling pathway is activated by various types of cellular stimuli or pathogenic infection, and then regulates fundamental cellular functions to combat these stimulations. Here, we studied the meaningful roles of PI3K/AKT/p53 in regulating cellular machine such as autophagy, immune responses, as well as antiviral activity in Chinese perch brain (CPB) cells infected by infectious spleen and kidney necrosis virus (ISKNV), which is an agent caused devastating losses in mandarin fish (Siniperca chuatsi) industry. We found that ISKNV infection induced up-regulation of host PI3K/AKT/p53 axis, but inhibited autophagy in CPB cells. Interestingly, activation of PI3K/AKT/p53 axis factors trough agonists or overexpression dramatically decreased host autophagy level, inhibited ISKNV replication, and elevated the expression of immune-related genes in CPB cells. In contrast, suppression of PI3K/AKT/p53 pathway by inhibitors or small interfering RNA (siRNA)-mediated gene silence increased the autophagy and ISKNV replication, but down-regulated immune responses in CPB cells. All these results indicate that PI3K/AKT/p53 pathway plays an important role in anti-ISKNV infection and can be used as a new target for controlling ISKNV disease.

A novel C-type lectin LvCTL 4.2 has antibacterial activity but facilitates WSSV infection in shrimp (L. vannamei)

Glycan-binding protein C-type lectin (CTL), one of the pattern recognition receptors (PRRs), binds to carbohydrates on the surface of pathogens and elicits antimicrobial responses in shrimp innate immunity. The objective was to identify and characterize a novel C-type lectin LvCTL 4.2 in Litopenaeus vannamei. The LvCTL 4.2 protein consisted of a signal peptide at the N terminal and a carbohydrate-recognition domain (CRD) with a mutated mannose-binding (Glu-Pro-Ala; EPA) motif at the C terminal, and thereby has a putative secreted mannose-binding C-type lectin architecture. LvCTL 4.2 was highly expressed in nervous tissue and stomach. Infection with white spot syndrome virus (WSSV) induced expression of LvCTL 4.2 in shrimp stomach at 12 h post infection. Conversely, there was no obvious upregulation in expression of LvCTL 4.2 in stomach or hepatopancreas of shrimp with AHPND (acute hepatopancreas necrosis disease). Pathogen binding assays confirmed recombinant LvCTL 4.2 protein (rLvCTL 4.2) had significant binding ability with the WSSV virion, Gram-negative, and Gram-positive bacteria. Moreover, rLvCTL 4.2 had strong growth inhibition of Vibrio parahaemolyticus. Silencing LvCTL 4.2 suppressed WSSV replication, whereas pretreatment of WSSV with rLvCTL 4.2 facilitated viral replication in vivo. In conclusion, LvCTL 4.2 acted as a PRR that inhibited AHPND-causing bacteria, but facilitated WSSV pathogenesis.

Alteration in Cellular Signaling and Metabolic Reprogramming during Viral Infection

Cellular activities are finely regulated by numerous signaling pathways to support specific functions of complex life processes. Viruses are obligate intracellular parasites. Each step of viral replication is ultimately governed by the interaction of a virus with its host cells. Because of the demands of viral replication, the nutritional needs of virus-infected cells differ from those of uninfected cells. To improve their chances of survival and replication, viruses have evolved to commandeer cellular processes, including cell metabolism, augmenting these processes to support their needs. This article summarizes recent findings regarding virus-induced alterations to major cellular metabolic pathways focusing on how viruses modulate various signaling cascades to induce these changes. We begin with a general introduction describing the role played by signaling pathways in cellular metabolism. We then discuss how different viruses target these signaling pathways to reprogram host metabolism to favor the viral needs. We highlight the gaps in understanding metabolism-related virus-host interactions and discuss how studying these changes will enhance our understanding of fundamental processes involved in metabolic regulation. Finally, we discuss the potential to harness these processes to combat viral diseases, as well as other diseases, including metabolic disorders and cancers.

Litopenaeus vannamei Sma and Mad related protein 5 gene is involved in stress response and white spot syndrome virus infection

Cell survival is based on the stability of intracellular state. It was well known that biochemical reactions in cells require specific intracellular environments, such as pH and calcium concentration. While the mechanism of stabilizing the intracellular environment is complex and far from clear. In this study, a Sma and Mad related protein 5 gene (LvSmad5) of Litopenaeus vannamei was cloned. LvSmad5 was located to both cytoplasm and nucleus. And subcellular localization of LvSmad5 was responsed to the changing of cells internal and external environment. Besides, it was found that subcellular localization of LvSmad5 was also regulated by unfolded protein response. Moreover, it was proved that nucleic localization of LvSmad5 could significantly increase the white spot syndrome virus (WSSV) infection in shrimp, and knockdown expression of LvSmad5 decreased the cumulative mortality of WSSV infection shrimp. Further investigation revealed that cytoplasm LvSmad5 could interplay with shrimp hexokinase 1, and contribute to glycolysis. These results indicated that LvSmad5 played a role in L. vannamei environmental stress response, and was used by WSSV for its replication.

Integrated Metabolomics and Transcriptomics Analyses Reveal Metabolic Landscape in Neuronal Cells during JEV Infection

Japanese encephalitis virus (JEV) is a leading cause of viral encephalitis in endemic regions of Asia. The neurotropism of JEV and its high-efficiency replication in neurons are the key events for pathogenesis. Revealing the interplay between virus and host cells in metabolic facet is of great importance both for unraveling the pathogenesis mechanisms and providing novel antiviral targets. This study took advantage of the integration analysis of metabolomics and transcriptomics to depict the metabolic profiles of neurons during the early stage of JEV infection. Increased glycolysis and its branched pentose phosphate pathway (PPP) flux and impaired oxidative phosphorylation (OXPHOS) in glucose utilization, and the catabolic patterns of lipid metabolism were created to facilitate the biosynthesis of precursors needed for JEV replication in neurons. Pharmacological inhibitions of both glycolysis pathway and PPP in neurons suggested its indispensable role in maintaining the optimal propagation of JEV. In addition, analysis of metabolomic-transcriptomic regulatory network showed the pivotal biological function of lipid metabolism during JEV infection. Several pro-inflammatory lipid metabolites were significantly up-regulated and might partially be responsible for the progression of encephalitis. These unique metabolic reprogramming features might give deeper insight into JEV infected neurons and provide promising antiviral approaches targeting metabolism.

Host metabolic reprogramming in response to SARS-CoV-2 infection: A systems biology approach

Understanding the pathogenesis of SARS-CoV-2 is essential for developing effective treatment strategies. Viruses hijack the host metabolism to redirect the resources for their replication and survival. The influence of SARS-CoV-2 on host metabolism is yet to be fully understood. In this study, we analyzed the transcriptomic data obtained from different human respiratory cell lines and patient samples (nasopharyngeal swab, peripheral blood mononuclear cells, lung biopsy, bronchoalveolar lavage fluid) to understand metabolic alterations in response to SARS-CoV-2 infection. We explored the expression pattern of metabolic genes in the comprehensive genome-scale network model of human metabolism, Recon3D, to extract key metabolic genes, pathways, and reporter metabolites under each SARS-CoV-2-infected condition. A SARS-CoV-2 core metabolic interactome was constructed for network-based drug repurposing. Our analysis revealed the host-dependent dysregulation of glycolysis, mitochondrial metabolism, amino acid metabolism, nucleotide metabolism, glutathione metabolism, polyamine synthesis, and lipid metabolism. We observed different pro- and antiviral metabolic changes and generated hypotheses on how the host metabolism can be targeted for reducing viral titers and immunomodulation. These findings warrant further exploration with more samples and in vitro studies to test predictions.

Phosphorylation of Shrimp Tcf by a Viral Protein Kinase WSV083 Suppresses Its Antiviral Effect

Nuclear DNA-binding TCF proteins, which act as the main downstream effectors of Wnt signaling, are essential for the regulation of cell fate and innate immunity. However, their role during viral infection in shrimp remains unknown. Herein, we demonstrated that Litopenaeus vannamei TCF (LvTcf) acts independently of Lvβ-catenin to promote interferon-like protein LvVago1 production, thus mounting the response to WSSV infection. Further, we observed that WSV083, a WSSV serine/threonine protein kinase, bound to LvTcf and phosphorylated it. Phosphorylated LvTcf was then recognized and degraded via the ubiquitin-proteasome pathway. Moreover, mass spectrometry analyses indicated that the T39 and T104 residues of LvTcf were target sites phosphorylated by WSV083. Point mutation analyses suggested that additional sites of LvTcf may undergo phosphorylation via WSV083. Taken together, the current work provides valuable insights into host immunity and viral pathogenesis. LvTcf is not only a modulator of shrimp innate immunity but is also an important target for WSSV immune evasion. Thus, the current findings will help improve disease control in shrimps.

Blood glucose promotes dengue virus infection in the mosquito Aedes aegypti

Background

Dengue fever is the most rapidly spreading mosquito-borne viral disease globally. More than 2.5 billion people live in dengue-endemic areas. Previous studies suggested an interrelationship between diabetes mellitus (DM) and dengue hemorrhagic fever (DHF). Conversely, glycolysis is a critical metabolic pathway for optimal dengue virus (DENV) replication. However, little is known concerning the effect of glucose on DENV replication in mosquitoes. In this study, we investigated the impact of glucose on DENV replication in mosquitoes Aedes aegypti.

Methods

Mosquitoes (Ae. aegypti UGAL/Rockefeller strain) were orally infected with DENV (serotype 2, 16681 strain) through infectious blood feeding. The DENV infection and transmission rates were determined by examining mosquito bodies and saliva, respectively, for DENV positivity at different time points after infection. In addition, a reverse genetic approach was applied by introducing double-stranded RNA against genes of interest into the mosquitoes to inhibit gene expression.

Results

Our data revealed a significant increase of DENV genome levels in mosquitoes consuming an infectious blood meal supplemented with glucose, suggesting that blood glucose is an important factor for viral replication. Interestingly, a significant increase of DENV E protein levels was detected in the saliva 4 days faster in mosquitoes that consumed infectious blood meals supplemented with glucose than in those consuming infectious blood meals alone. Furthermore, we perform RNAi to silence AKT or TOR and investigate the molecular mechanism regulating the glucose-mediated enhancement of viral replication. Silencing of AKT or TOR significantly reduced DENV titers in mosquitoes.

Conclusions

This study suggested that blood glucose is beneficial to DENV replication and that it facilitates virus transmission in mosquitoes via AKT and TOR signaling. Therefore, our results strengthen our understanding of dengue fever and DM co-morbidity and possibly reveal new targets for specific antiviral therapies.

Graphical abstract

Different Immune Responses of the Lymphoid Organ in Shrimp at Early Challenge Stage of Vibrio parahaemolyticus and WSSV

Simple Summary

Disease is a frequently encountered problem in aquaculture, which always causes global economic losses. White spot syndrome virus (WSSV) and Vibrio parahaemolyticus are two of the most destructive pathogens causing severe loss of shrimp aquaculture. Understanding the host immune responses against different pathogens is vital for developing effective disease control technologies. The lymphoid organ is a vital part of the shrimp immune system and exhibits important immune functions including cellular and humoral immunity. However, the immune function of the lymphoid organ and its responses against different pathogens are still largely unclear. In the present study, transcriptomic analysis was applied to compare the differentially expressed genes (DEGs) in the lymphoid organ of shrimp after Vibrio or WSSV challenge. Data showed that Vibrio challenge induced broad immune responses in the lymphoid organ including activation of several pattern recognition receptors, the proPO activating system, phagocytosis related genes, and immune effectors. In contrast, the immune responses seemed to be inhibited after WSSV infection. The present study suggests that the shrimp lymphoid organ plays different functions in response to the infection of distinct pathogens at early stage, which provides new insights into the immune functions of lymphoid organ in shrimp.

Abstract

The lymphoid organ is an essential part of the immune system involved in cellular and humoral immune responses in shrimp. However, its roles in the immune responses against different pathogens are still largely unclear. In the present study, transcriptomic analysis was applied to compare the differentially expressed genes (DEGs) in the lymphoid organ of shrimp after Vibrio or WSSV challenge. In total, 2127 DEGs were screened in the lymphoid organ of shrimp at 6 h post Vibrio parahaemolyticus injection, and 1569 DEGs were obtained at the same time after WSSV challenge. KEGG pathway enrichment analysis of these DEGs revealed that two significantly enriched pathways including “neuroactive ligand–receptor interaction” and “protein digestion and absorption” were responsive to both pathogens. In contrast, “lysosome” was the significantly enriched pathway only in Vibrio challenge whereas carbohydrate metabolism related pathways were the significantly enriched pathways only in WSSV challenge. Further analysis on immune-related DEGs showed that Vibrio challenge induced broad immune responses in the lymphoid organ including activation of several pattern recognition receptors, the proPO activating system, phagocytosis related genes, and immune effectors. In contrast, the immune responses seemed to be inhibited after WSSV infection. The data suggest that the shrimp lymphoid organ plays different functions in response to the infection of distinct pathogens at the early stage, which provides new insights into the immune functions of lymphoid organ in shrimp.

Immunometabolism Modulation in Therapy

The study of cancer biology should be based around a comprehensive vision of the entire tumor ecosystem, considering the functional, bioenergetic and metabolic state of tumor cells and those of their microenvironment, and placing particular importance on immune system cells. Enhanced understanding of the molecular bases that give rise to alterations of pathways related to tumor development can open up new therapeutic intervention opportunities, such as metabolic regulation applied to immunotherapy. This review outlines the role of various oncometabolites and immunometabolites, such as TCA intermediates, in shaping pro/anti-inflammatory activity of immune cells such as MDSCs, T lymphocytes, TAMs and DCs in cancer. We also discuss the extraordinary plasticity of the immune response and its implication in immunotherapy efficacy, and highlight different therapeutic intervention possibilities based on controlling the balanced systems of specific metabolites with antagonistic functions.

Co-opting of nonATP-generating glycolytic enzymes for TBSV replication

Positive-strand RNA viruses build viral replication organelles (VROs) with the help of co-opted host factors. The energy requirement of intensive viral replication processes is less understood. Previous studies on tomato bushy stunt virus (TBSV) showed that tombusviruses hijack two ATP-producing glycolytic enzymes to produce ATP locally within VROs. In this work, we performed a cDNA library screen with Arabidopsis thaliana proteins and the TBSV p33 replication protein. The p33 - plant interactome contained highly conserved glycolytic proteins. We find that the glycolytic Hxk2 hexokinase, Eno2 phosphopyruvate hydratase and Fba1 fructose 1,6-bisphosphate aldolase are critical for TBSV replication in yeast or in a cell-free replicase reconstitution assay. The recruitment of Fba1 is important for the local production of ATP within VROs. Altogether, our data support the model that TBSV recruits and compartmentalizes possibly most members of the glycolytic pathway. This might allow TBSV to avoid competition with the host for ATP.