bims-mevinf 2025-08-24 papers

J Virol. 2025 Aug 19. e0057925

Human cytomegalovirus promotes de novo PC synthesis during early virus replication.

Ian Kline, Rebekah L Mokry, Yuecheng Xi, Magí Passols Manzano, Sidnie Layesa, Nowroz Sohrab Ali, Melissa A Moy, Felicia D Goodrum, John G Purdy.

Human cytomegalovirus (HCMV) infection reprograms metabolism, including lipid synthesis. While several metabolite-related pathways exhibit altered activity in infected cells, the alteration of lipid-related pathways by HCMV has not been examined beyond fatty acid synthesis and elongation. In this study, we addressed this lack of understanding by focusing on phosphatidylcholine (PC), a class of lipids we previously showed is increased by HCMV infection in human foreskin fibroblasts. Here, we expand upon this finding by demonstrating that HCMV infection increases the abundance of PCs in several different fibroblasts and, similarly, in endothelial and epithelial cells. Additionally, HCMV elevates PC levels regardless of the level of confluency, type of growth medium, and presence of serum. Next, we investigated if HCMV alters the activity in the three PC synthesis pathways. We demonstrate that HCMV infection promotes the activity in the de novo PC synthesis pathway using a 13C-choline isotopic tracer and liquid chromatography high-resolution tandem mass spectrometry. Infection did not alter the activity in the other two pathways. Moreover, we examined the kinetics of PC remodeling by HCMV and found that PC synthesis was promoted and the PC lipidome shifted after 24 h post-infection. Furthermore, we found that PC remodeling occurred when DNA synthesis and subsequent steps of virus replication were inhibited by phosphonoacetic acid. Overall, this work suggests that the early steps of HCMV replication promote the reprogramming of host lipid metabolism to ensure the synthesis of a lipidome necessary to support HCMV infection.IMPORTANCEHuman cytomegalovirus (HCMV) is a common herpesvirus that establishes a lifelong and persistent infection in its human host. HCMV infection in most people does not cause overt disease. However, in immunocompromised individuals, severe CMV-associated disease can lead to permanent disabilities and even death. Additionally, congenital CMV is the leading infectious cause of birth defects. Viruses have evolved to hijack host metabolic pathways to facilitate their replication cycle. In this study, we determine that HCMV promotes the activity in the de novo pathway of phosphatidylcholine (PC) synthesis. We demonstrate that the activity in the other PC synthesis pathways, the phosphatidylethanolamine N-methyltransferase and Lands cycles, is unaltered by HCMV infection. Moreover, we found that HCMV infection alters metabolic activity to increase the PC lipidome before 48 h post-infection. Additionally, our results suggest that immediate-early and early gene expression promotes changes in PC lipids. Together, our findings demonstrate that infection promotes the de novo PC pathway to increase PC lipids during the early stages of virus replication.

Keywords: human cytomegalovirus; lipid metabolism; metabolic reprogramming; phosphatidylcholine

DOI: https://doi.org/10.1128/jvi.00579-25

Nat Commun. 2025 Aug 19. 16(1): 7721

O-GlcNAc transferase plays dual antiviral roles by integrating innate immunity and lipid metabolism.

Viral infection induces robust reprogramming of metabolic pathways in host cells. However, whether host metabolic enzymes detect viral components remains unknown. Our group and others previously identified O-GlcNAc transferase (OGT), an important glucose metabolic enzyme, as a crucial mediator of the antiviral immune responses. Here, by studying a mouse model with a catalytically impaired OGT, we discover a catalytic activity-independent function of OGT in restraining influenza A virus (IAV) infection in addition to its catalytic activity-dependent effect on MAVS-mediated antiviral immunity. Biochemical studies reveal a critical antiviral effect based on OGT interacting with IAV genomic RNA that requires its N-terminal tetracopeptide repeat-4 motif. This interaction causes the translocation of nuclear OGT to cytosolic lipid droplets (LDs) to destabilize LDs-coating perilipin 2, thereby limiting LDs accumulation and in turn virus replication. In sum, our findings reveal OGT as a multifaceted metabolic sensor that integrates MAVS signaling and lipid metabolism to combat viral infection.

DOI: https://doi.org/10.1038/s41467-025-63085-y

BMC Vet Res. 2025 Aug 19. 21(1): 518

Isolation and identification of a new porcine astrovirus 5 demonstrated that oxidative stress enhances porcine astrovirus replication.

Yiyang Du, Yibin Qin, Xiaoying Feng, Yuhang Luo, Yueqing Lv, Shichuan Song, Xiaofang Wei, Kang Ouyang, Yeshi Yin, Ying Chen, Zuzhang Wei, Weijian Huang, Yifeng Qin.

BACKGROUND: Porcine astrovirus (PAstV) poses a major risk to the pig industry by causing diarrhea in suckling piglets. Despite its global prevalence and five genotypes, the virus's pathogenic mechanism is not well understood due to difficulties in isolating and culturing it in vitro. Studying PAstV from clinical samples and its interaction with host cells is crucial for understanding its pathogenesis and developing antiviral treatments.
METHODS: To isolate porcine astrovirus (PAstV) from clinical specimens, fecal samples from PAstV-positive pigs were collected in August 2018, inoculated into PK-15 cells, and subjected to three successive blind passages. The in vitro growth characteristics of the isolated strain were subsequently evaluated, and the morphology of the virus particles was examined through electron microscopy. The complete genome sequence of the isolated strain was determined, followed by sequence alignment, homology analysis, phylogenetic analysis, and recombination analysis. To investigate the induction of reactive oxygen species (ROS) production in PK-15 cells infected with the isolated strain, the cells were infected, and ROS production was quantified using the MitoSOX probe. Furthermore, the expression levels of the antioxidant factors Nrf2 and HO-1 were analyzed via Western blotting. Mitochondrial damage resulting from PAstV infection was observed using transmission electron microscopy, and the effect of PAstV infection on mitochondrial membrane potential was assessed using the JC-1 probe. Finally, the impact of ROS on PAstV replication was explored using IFA and RT-qPCR.
RESULTS: In this study, a strain of PAstV was isolated from porcine fecal samples, demonstrating an ability to adapt effectively to PK-15 cells with a viral titer reaching up to 10^7.85 TCID50/mL. Genetic evolution analysis classified the isolated strain as PAstV5, revealing high genetic homology with other representative PAstV5 strains. The isolated strain was designated as PAstV5-GX2. Sequence alignment identified 11 consecutive amino acid deletions at the 3' end of ORF1a in the PAstV5-GX2 strain, resulting in alterations to the three-dimensional structure of the nsp1a/4 protein. Further investigation indicated that PAstV infection in PK-15 cells enhances mitochondrial ROS production and diminishes the protein expression levels of the antioxidant molecules Nrf2 and HO-1. Concurrently, PAstV infection induces mitochondrial swelling, cristae rupture, and vacuolization, along with a reduction in mitochondrial membrane potential. Through the application of H2O2 and NAC to modulate cellular ROS levels, it was determined that ROS can facilitate viral replication.
CONCLUSIONS AND RELEVANCE: Our study successfully isolated a novel strain of PAstV5 characterized by an 11-amino acid deletion in the nsp1a protein, leading to significant alterations in the three-dimensional structure of the nsp1a/4 protein. This strain was observed to induce the production of mitochondrial ROS, downregulate the expression of Nrf2 and HO-1, and cause mitochondrial damage. Furthermore, the generation of mitochondrial ROS was found to facilitate the replication of PAstV. These findings offer valuable insights into the genetic evolution and pathogenic mechanisms of PAstV.

Keywords: Genomic analysis; Isolation; Mitochondrial damage; Oxidative stress; Porcine astrovirus 5

DOI: https://doi.org/10.1186/s12917-025-04939-x

bioRxiv. 2025 Aug 12. pii: 2025.08.12.669648. [Epub ahead of print]

Oxidative Stress and Interferon Signaling Drive Differential Pathogenesis of Ancestral and Contemporary Zika Viruses in Human Cerebral Organoids.

Alfred T Harding, Yichen Zhang, Jane-Jane Chen, Jenna M Antonucci, Alexsia Richards, Valerie Leger, Charles A Whittaker, Yann S Vanrobaeys, Divyansh Agarwal, Tenzin Lungjangwa, Rudolf Jaenisch, Lee Gehrke.

Neurotropic Zika viruses (ZIKV) cause serious human disease with pandemic potential. Pathogenesis severities resulting from Asian/American versus African ZIKV lineage infections range from mild to severe, respectively; however, mechanisms underlying differential ZIKV pathogenesis remain unclear, as do effective therapeutic strategies. The limitations of mechanistic understanding are due in part to the challenges of comparing data generated in disparate experimental models, as well as approaches that did not test both ancestral and contemporary ZIKV infections. The goal of this work was to define differential pathogenesis mechanisms among ancestral and contemporary ZIKVs by direct infection comparisons using a relevant human stem cell-derived cerebral organoid experimental model. While Asian/American ZIKV lineage infections enhanced antiviral and interferon gene expression responses that correlated with viral RNA clearance from organoid ventricles, ancestral African lineage ZIKV infections enhanced apoptotic and stress response signaling that correlated with diminished STAT2 signaling protein levels, ongoing ZIKV replication, and production of damaging reactive oxygen species (ROS). We discovered that, surprisingly, severe ancestral Zika virus pathogenesis was dramatically reduced by Trolox, a hydroxyl radical scavenger antioxidant, thereby confirming ROS imbalance as a major pathogenesis driver. These results demonstrate that ZIKV lineage infections and pathogenesis are differentiated by their signaling responses and suggest that preventing or controlling hydroxyl radical imbalance may offer therapeutic benefits to address microcephaly and Congenital Zika Virus Syndrome.
One Sentence Summary: Differential signal transduction responses to lineage-specific Zika virus infections cause reduction-oxidation imbalance-mediated pathogenesis that is blocked by Trolox, an antioxidant.

DOI: https://doi.org/10.1101/2025.08.12.669648

J Virol. 2025 Aug 19. e0100325

Elevated peripheral and nervous system inflammation is associated with decreased short-chain fatty acid levels in Zika virus-infected macaques.

Zika virus (ZIKV) infection typically results in mild symptoms; however, it can cause elevated inflammation in the CNS and the development of more serious conditions, including severe neurological syndromes. Previous studies have demonstrated that ZIKV infection may cause mucosal dysfunction as well as elevated inflammation in rectal and vaginal mucosal tissue. Here, we used non-human primate (NHP) models and clinical specimens from ZIKV-infected humans to examine microbiome, inflammation, and microbial translocation in the gut, blood, and CNS. We observed elevated markers indicative of microbial translocation and inflammation in the CNS of ZIKV-infected macaques and humans. While overall taxonomic shifts in microbial communities did not differ, bacterial-derived short-chain fatty acid (SCFA) levels were reduced. Decreased SCFA levels significantly negatively correlated with elevated peripheral and CNS inflammatory markers, suggesting a link between ZIKV-driven disease pathology and microbial function. Taken together, our study provides new insight into a previously unconsidered mechanism underlying ZIKV pathogenesis.IMPORTANCEZika virus poses a significant burden on public health, demonstrated by the 2015-2016 epidemic that remains with devastating health consequences especially in countries such as Brazil. However, the mechanisms that underlie what leads to inflammation of the central and peripheral nervous system and disease in Zika virus have been poorly characterized. Here, we demonstrated that Zika virus resulted in gut microbiome dysbiosis, which led to decreased short-chain fatty acids, increased inflammation, and microbial translocation, likely brought on by reduced gut barrier integrity. This study represents the first evidence that microbial dysbiosis and gut damage may underlie Zika virus pathogenesis and ensuing neurological effects, providing a potential target for intervention for future virus pandemics.

Keywords: Zika virus; central nervous system; cerebrospinal fluid; inflammation; kynurenine pathway; microbiome; neopterin; serotonin; short-chain fatty acids; tryptophan catabolism

DOI: https://doi.org/10.1128/jvi.01003-25

Virology. 2025 Aug 14. pii: S0042-6822(25)00271-5. [Epub ahead of print]611 110658

Murine β-coronavirus MHV-RSA59 orchestrates the interplay of oxidative stress and inflammatory pathways in neuroinflammation.

Debina Bhattacharyya, Jayasri Das Sarma.

Mouse Hepatitis Virus MHV-A59/RSA59 is hepato-neurotropic strain known to induce an array of stress pathways leading to severe neuroinflammation and demyelination. Previous studies have explored the ability of MHV-A59 or RSA59 to modulate host stress pathways to exert its pathogenic effects. Oxidative and inflammatory stress are critical in neuroinflammation and demyelination, leading to different virus-induced neurodegeneration and associated pathogenesis. Various studies have linked the role of iNOS in the crosstalk of oxidative-inflammatory stress. This study aims to investigate the crosstalk of oxidative stress and inflammatory pathways in M-CoV-MHV-RSA59 infection in a reductionist model in neuronal Neuro2A and astrocytoma DBT cells. Our findings demonstrate that while Neuro2A cells exhibited a persistent increase in ROS levels, leading to upregulation of Nrf2 and its downstream antioxidant enzymes HMOX1 and Catalase, astrocytoma DBT cells displayed a transient ROS peak with an initial downregulation of Nrf2 and impaired antioxidant response. Additionally, we observed differential regulation of key stress responders, such as XBP-1 and DJ-1, highlighting distinct cellular adaptations to viral infection. The inflammatory mediators NF-κB and iNOS activation patterns further underscored the differential inflammatory response, with sustained upregulation in Neuro2A cells, whereas DBT cells showed delayed activation. These findings suggest that neuronal cells engage an intrinsic antioxidant defense, while glial cells exhibit a compromised response. Our study provides mechanistic insights into oxidative and inflammatory crosstalk in the neuro-glial Neuro2A and DBT cells and in MHV-induced neuroinflammation, offering potential therapeutic targets for ameliorating neurodegenerative demyelinating disorders such as multiple sclerosis.

Keywords: MHV-A59; Mouse hepatitis virus; NF-κB; Neuro-inflammation; Nrf-2; Oxidative stress; RSA59; Reactive oxygen species or ROS; TNF-α; iNOS

DOI: https://doi.org/10.1016/j.virol.2025.110658