SARS-CoV-2 accessory protein ORF8 is secreted extracellularly as a glycoprotein homodimer

Journal of Biological Chemistry, Journal Year: 2022, Volume and Issue: 298(3), P. 101724 - 101724

Published: Feb. 11, 2022

ORF8 is an accessory protein encoded by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Consensus regarding the biological functions of lacking, largely because fundamental characteristics this in cells have not been determined. To clarify these features, we herein established expression system 293T cells. Using system, approximately 41% expressed were secreted extracellularly as a glycoprotein homodimer with inter/intramolecular disulfide bonds. Intracellular was sensitive to glycosidase Endo H, whereas portion Endo-H-resistant, suggesting that secretion occurs via conventional pathway. Additionally, immunoblotting analysis showed total amounts major histocompatibility complex class Ι (MHC-I), angiotensin-converting enzyme (ACE2), and SARS-CoV-2 spike (CoV-2 S) proteins coexpressed changed increased expression, although FACS revealed cell surface MHC-I protein, but ACE2 CoV-2 S proteins, reduced expression. Finally, demonstrate RNA-seq had no significant stimulatory effects human primary monocyte-derived macrophages (MDMs). Taken together, our results provide evidence acts homodimer, its are likely associated intracellular transport and/or extracellular signaling infection.

Language: Английский

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SARS-CoV-2 ORF8: A Rapidly Evolving Immune and Viral Modulator in COVID-19

Viruses, Journal Year: 2023, Volume and Issue: 15(4), P. 871 - 871

Published: March 29, 2023

The COVID-19 pandemic has resulted in upwards of 6.8 million deaths over the past three years, and frequent emergence variants continues to strain global health. Although vaccines have greatly helped mitigate disease severity, SARS-CoV-2 is likely remain endemic, making it critical understand its viral mechanisms contributing pathogenesis discover new antiviral therapeutics. To efficiently infect, this virus uses a diverse set strategies evade host immunity, accounting for high pathogenicity rapid spread throughout pandemic. Behind some these evasion accessory protein Open Reading Frame 8 (ORF8), which gained recognition due hypervariability, secretory property, unique structure. This review discusses current knowledge on ORF8 proposes actualized functional models describing pivotal roles both replication immune evasion. A better understanding ORF8’s interactions with factors expected reveal essential pathogenic utilized by inspire development novel therapeutics improve outcomes.

Language: Английский

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Positive selection underlies repeated knockout of ORF8 in SARS-CoV-2 evolution

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 13, 2024

Knockout of the ORF8 protein has repeatedly spread through global viral population during SARS-CoV-2 evolution. Here we use both regional and pathogen sequencing to explore selection pressures underlying its loss. In Washington State, identified transmission clusters with knockout throughout evolution, not just on novel, high fitness backbones. Indeed, is truncated more frequently knockouts circulate for longer than any other gene. Using a phylogeny, find evidence positive explain this phenomenon: nonsense mutations resulting in shortened products occur are associated faster clade growth rates synonymous ORF8. Loss also reduced clinical severity, highlighting diverse impacts

Language: Английский

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SARS-CoV-2 ORF8 as a Modulator of Cytokine Induction: Evidence and Search for Molecular Mechanisms

Viruses, Journal Year: 2024, Volume and Issue: 16(1), P. 161 - 161

Published: Jan. 22, 2024

Severe cases of SARS-CoV-2 infection are characterized by an immune response that leads to the overproduction pro-inflammatory cytokines, resulting in lung damage, cardiovascular symptoms, hematologic acute kidney injury and multiple organ failure can lead death. This remarkable increase cytokines other inflammatory molecules is primarily caused viral proteins, particular interest has been given ORF8, a unique accessory protein specific SARS-CoV-2. Despite plenty research, precise mechanisms which ORF8 induces proinflammatory not clear. Our investigations demonstrated augments production IL-6 induced Poly(I:C) human embryonic (HEK)-293 monocyte-derived dendritic cells (mono-DCs). We discuss our findings multifaceted roles as modulator cytokine response, focusing on type I interferon IL-6, key component In addition, we explore hypothesis may act through pattern recognition receptors dsRNA such TLRs.

Language: Английский

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Reverse genetics systems for SARS-CoV-2: Development and applications

Virologica Sinica, Journal Year: 2023, Volume and Issue: 38(6), P. 837 - 850

Published: Oct. 11, 2023

The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused serious harm to human health and struck a blow global economic development. Research on SARS-CoV-2 has greatly benefited from the use reverse genetics systems, which have been established artificially manipulate viral genome, generating recombinant reporter infectious viruses or biosafety level (BSL-2)-adapted non-infectious replicons with desired modifications. These tools instrumental in studying molecular biological characteristics virus, investigating antiviral therapeutics, facilitating development attenuated vaccine candidates. Here, we review construction strategies, development, applications systems for SARS-CoV-2, may be applied other CoVs as well.

Language: Английский

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SARS-CoV-2 ORF8 accessory protein is a virulence factor

mBio, Journal Year: 2023, Volume and Issue: 14(5)

Published: Aug. 25, 2023

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) encodes six accessory proteins (3a, 6, 7a, 7b, 8, and 9b) for which limited information is available on their role in pathogenesis. We showed that the deletion of open reading frames (ORFs) or 7b individually did not significantly impact viral pathogenicity humanized K18-hACE2 transgenic mice. In contrast, ORF8 partially attenuated SARS-CoV-2, resulting reduced lung pathology 40% less mortality, indicating a critical determinant SARS-CoV-2 Attenuation SARS-CoV-2-∆8 was associated with significant decrease replication either lungs mice organoid-derived human airway cells. An increase interferon signaling at early times post-infection (1 dpi) pro-inflammatory response late post-infection, both (6 cells [72 hours (hpi)], were observed. The early, but prolonged, along lower inflammatory could explain partial attenuation SARS-CoV-∆8. presence an number macrophages addition, supernatant SARS-CoV-2-WT (wild-type)-infected enhanced activation as compared to SARS-CoV-2-∆8-infected These results show virulence factor involved inflammation be targeted COVID-19 therapies. IMPORTANCE relevance severe pathogenesis unclear. Virus natural isolates deletions wild milder disease, suggesting might contribute virulence. This manuscript shows two experimental systems: identify protein potential target

Language: Английский

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SARS-CoV-2 ORF8 Mediates Signals in Macrophages and Monocytes through MyD88 Independently of the IL-17 Receptor

The Journal of Immunology, Journal Year: 2023, Volume and Issue: 211(2), P. 252 - 260

Published: June 2, 2023

Abstract SARS-CoV-2 has caused an estimated 7 million deaths worldwide to date. A secreted accessory protein, known as open reading frame 8 (ORF8), elicits inflammatory pulmonary cytokine responses and is associated with disease severity in COVID-19 patients. Recent reports proposed that ORF8 mediates downstream signals macrophages monocytes through the IL-17 receptor complex (IL-17RA, IL-17RC). However, generally are found be restricted nonhematopoietic compartment, thought due rate-limiting expression of IL-17RC. Accordingly, we revisited capacity induce gene mouse human monocytes. In SARS-CoV-2–infected lungs, IL17RC mRNA was undetectable monocyte/macrophage populations. cultured macrophages, but not led elevated target cytokines. ORF8-induced signaling fully preserved presence anti–IL-17RA/RC neutralizing Abs Il17ra−/− cells. also operative Il1r1−/− bone marrow–derived macrophages. TLR/IL-1R family adaptor MyD88, which dispensable for IL-17R signaling, required activity yet MyD88 signaling. Thus, conclude transduces via independently IL-17R.

Language: Английский

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Tubular ER structures shaped by ER-phagy receptors engage in stress-induced Golgi bypass

Developmental Cell, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

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Beyond Infection: The Role of Secreted Viral Proteins in Pathogenesis, Disease Severity and Diagnostic Applications

Cells, Journal Year: 2025, Volume and Issue: 14(9), P. 624 - 624

Published: April 22, 2025

Secreted viral proteins are crucial in virus–host interactions, as they modify the host microenvironment to promote infection. These secreted could alter immune and inflammatory responses, allowing viruses evade defense mechanisms such cytotoxic T cell activation antibody neutralization. Some mimic molecules suppress antiviral making them valuable targets for antivirals diagnostics. Notable examples include BARF1 from Epstein–Barr virus, associated with gastric cancer; vIL-10 which regulates responses contributes autoimmune diseases; NS1 dengue vascular permeability early diagnosis; NSP4 rotavirus an enterotoxin, among others. The study of these improves our understanding pathogenesis helps develop innovative treatments infectious non-infectious diseases, taking advantage evolutionary adaptations viruses. This review explores their impact on infection cycle, disease progression, key processes, cycle regulation, apoptosis, signaling. Research deepens basic knowledge virology generates alternative methods detecting biomarkers creating more effective therapies, well implementing some emerging technologies, biosensors plasmon resonance, diagnosis diseases.

Language: Английский

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A neonatal mouse model characterizes transmissibility of SARS-CoV-2 variants and reveals a role for ORF8

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: May 25, 2023

Abstract Small animal models have been a challenge for the study of SARS-CoV-2 transmission, with most investigators using golden hamsters or ferrets. Mice advantages low cost, wide availability, less regulatory and husbandry challenges, existence versatile reagent genetic toolbox. However, adult mice do not robustly transmit SARS-CoV-2. Here we establish model based on neonatal that allows transmission clinical isolates. We characterize tropism, respiratory tract replication ancestral WA-1 compared to variants Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), Omicron BA.1 BQ.1.1. identify inter-variant differences in timing magnitude infectious particle shedding from index mice, both which shape contact mice. Furthermore, two recombinant lacking either ORF6 ORF8 host antagonists. The removal shifts viral towards lower tract, resulting significantly delayed reduced our model. Our results demonstrate potential mouse determinants while revealing role an accessory protein this context.

Language: Английский

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