In SARS-CoV-2 delta variants, Spike-P681R and D950N promote membrane fusion, Spike-P681R enhances spike cleavage, but neither substitution affects pathogenicity in hamsters

EBioMedicine

2023 Apr 10

Furusawa, Y;Kiso, M;Iida, S;Uraki, R;Hirata, Y;Imai, M;Suzuki, T;Yamayoshi, S;Kawaoka, Y;
PMID: 37043872 | DOI: 10.1016/j.ebiom.2023.104561

The SARS-CoV-2 delta (B.1.617.2 lineage) variant was first identified at the end of 2020 and possessed two unique amino acid substitutions in its spike protein: S-P681R, at the S1/S2 cleavage site, and S-D950N, in the HR1 of the S2 subunit. However, the roles of these substitutions in virus phenotypes have not been fully characterized.We used reverse genetics to generate Wuhan-D614G viruses with these substitutions and delta viruses lacking these substitutions and explored how these changes affected their viral characteristics in vitro and in vivo.S-P681R enhanced spike cleavage and membrane fusion, whereas S-D950N slightly promoted membrane fusion. Although S-681R reduced the virus replicative ability especially in VeroE6 cells, neither substitution affected virus replication in Calu-3 cells and hamsters. The pathogenicity of all recombinant viruses tested in hamsters was slightly but not significantly affected.Our observations suggest that the S-P681R and S-D950N substitutions alone do not increase virus pathogenicity, despite of their enhancement of spike cleavage or fusogenicity.A full list of funding bodies that contributed to this study can be found under Acknowledgments.

Immunogenicity and protective efficacy of SARS-CoV-2 mRNA vaccine encoding secreted non-stabilized spike in female mice

Nature communications

2023 Apr 21

Prompetchara, E;Ketloy, C;Alameh, MG;Tharakhet, K;Kaewpang, P;Yostrerat, N;Pitakpolrat, P;Buranapraditkun, S;Manopwisedjaroen, S;Thitithanyanont, A;Jongkaewwattana, A;Hunsawong, T;Im-Erbsin, R;Reed, M;Wijagkanalan, W;Patarakul, K;Techawiwattanaboon, T;Palaga, T;Lam, K;Heyes, J;Weissman, D;Ruxrungtham, K;
PMID: 37085495 | DOI: 10.1038/s41467-023-37795-0

Establishment of an mRNA vaccine platform in low- and middle-income countries (LMICs) is important to enhance vaccine accessibility and ensure future pandemic preparedness. Here, we describe the preclinical studies of "ChulaCov19", a SARS-CoV-2 mRNA encoding prefusion-unstabilized ectodomain spike protein encapsulated in lipid nanoparticles (LNP). In female BALB/c mice, ChulaCov19 at 0.2, 1, 10, and 30 μg elicits robust neutralizing antibody (NAb) and T cell responses in a dose-dependent relationship. The geometric mean titers (GMTs) of NAb against wild-type (WT, Wuhan-Hu1) virus are 1,280, 11,762, 54,047, and 62,084, respectively. Higher doses induce better cross-NAb against Delta (B.1.617.2) and Omicron (BA.1 and BA.4/5) variants. This elicited immunogenicity is significantly higher than those induced by homologous CoronaVac or AZD1222 vaccination. In a heterologous prime-boost study, ChulaCov19 booster dose generates a 7-fold increase of NAb against Wuhan-Hu1 WT virus and also significantly increases NAb response against Omicron (BA.1 and BA.4/5) when compared to homologous CoronaVac or AZD1222 vaccination. Challenge studies show that ChulaCov19 protects human-ACE-2-expressing female mice from COVID-19 symptoms, prevents viremia and significantly reduces tissue viral load. Moreover, anamnestic NAb response is undetectable in challenge animals. ChulaCov19 is therefore a promising mRNA vaccine candidate either as a primary or boost vaccination and has entered clinical development.

Syrian hamster convalescence from prototype SARS-CoV-2 confers measurable protection against the attenuated disease caused by the Omicron variant

PLoS pathogens

2023 Apr 01

Ryan, KA;Bewley, KR;Watson, RJ;Burton, C;Carnell, O;Cavell, BE;Challis, A;Coombes, NS;Davies, ER;Edun-Huges, J;Emery, K;Fell, R;Fotheringham, SA;Gooch, KE;Gowan, K;Handley, A;Harris, DJ;Hesp, R;Hunter, L;Humphreys, R;Johnson, R;Kennard, C;Knott, D;Lister, S;Morley, D;Ngabo, D;Osman, KL;Paterson, J;Penn, EJ;Pullan, ST;Richards, KS;Summers, S;Thomas, SR;Weldon, T;Wiblin, NR;Rayner, EL;Vipond, RT;Hallis, B;Salguero, FJ;Funnell, SGP;Hall, Y;
PMID: 37014911 | DOI: 10.1371/journal.ppat.1011293

The mutation profile of the SARS-CoV-2 Omicron (lineage BA.1) variant posed a concern for naturally acquired and vaccine-induced immunity. We investigated the ability of prior infection with an early SARS-CoV-2 ancestral isolate (Australia/VIC01/2020, VIC01) to protect against disease caused by BA.1. We established that BA.1 infection in naïve Syrian hamsters resulted in a less severe disease than a comparable dose of the ancestral virus, with fewer clinical signs including less weight loss. We present data to show that these clinical observations were almost absent in convalescent hamsters challenged with the same dose of BA.1 50 days after an initial infection with ancestral virus. These data provide evidence that convalescent immunity against ancestral SARS-CoV-2 is protective against BA.1 in the Syrian hamster model of infection. Comparison with published pre-clinical and clinical data supports consistency of the model and its predictive value for the outcome in humans. Further, the ability to detect protection against the less severe disease caused by BA.1 demonstrates continued value of the Syrian hamster model for evaluation of BA.1-specific countermeasures.

SARS-CoV-2 Disease Severity in the Golden Syrian Hamster Model of Infection is Related to the Volume of Intranasal Inoculum.

preprints

2023 Feb 10

Handley, A;Ryan, K;Davies, E;Bewley, K;Carnell, O;Challis, A;Coombes, N;Fotheringham, S;Gooch, K;Charlton, M;Harris, D;Kennard, C;Ngabo, D;Weldon, T;Salguero, F;Funnell, S;Hall, Y;
| DOI: 10.20944/preprints202302.0171.v1

The Golden Syrian hamster (Mesocricetus auratus) is now commonly used in preclinical research for the study of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the assessment of vaccines, drugs and therapeutics. Here we show that hamsters inoculated via the intranasal route with the same infectious virus dose of prototypical SARS-CoV-2 administered in a different volume present with different clinical signs, weight loss and viral shedding, with a reduced volume resulting in reduced severity of disease similar to that obtained by a 500-fold reduction in challenge dose. The tissue burden of virus and the severity of pulmonary pathology were also significantly affected by different challenge inoculum volumes. These findings suggest that direct comparison between the severity of SARS-CoV-2 variants or studies assessing the efficacy of treatments determined by hamster studies cannot be made unless both the challenge dose and inoculation volume are matched when using the intranasal route. Additionally, analysis of sub-genomic and total genomic RNA PCR data demonstrated no link between sub-genomic and live viral titres and that sub-genomic analyses do not provide any information beyond that provided by more sensitive total genomic PCR.

Targeting lymphoid-derived IL-17 signaling to delay skin aging

Nature aging

2023 Jun 01

Solá, P;Mereu, E;Bonjoch, J;Casado-Peláez, M;Prats, N;Aguilera, M;Reina, O;Blanco, E;Esteller, M;Di Croce, L;Heyn, H;Solanas, G;Benitah, SA;
PMID: 37291218 | DOI: 10.1038/s43587-023-00431-z

Skin aging is characterized by structural and functional changes that contribute to age-associated frailty. This probably depends on synergy between alterations in the local niche and stem cell-intrinsic changes, underscored by proinflammatory microenvironments that drive pleotropic changes. The nature of these age-associated inflammatory cues, or how they affect tissue aging, is unknown. Based on single-cell RNA sequencing of the dermal compartment of mouse skin, we show a skew towards an IL-17-expressing phenotype of T helper cells, γδ T cells and innate lymphoid cells in aged skin. Importantly, in vivo blockade of IL-17 signaling during aging reduces the proinflammatory state of the skin, delaying the appearance of age-related traits. Mechanistically, aberrant IL-17 signals through NF-κB in epidermal cells to impair homeostatic functions while promoting an inflammatory state. Our results indicate that aged skin shows signs of chronic inflammation and that increased IL-17 signaling could be targeted to prevent age-associated skin ailments.

An inhaled bioadhesive hydrogel to shield non-human primates from SARS-CoV-2 infection

Nature materials

2023 Feb 09

Mei, X;Li, J;Wang, Z;Zhu, D;Huang, K;Hu, S;Popowski, KD;Cheng, K;
PMID: 36759564 | DOI: 10.1038/s41563-023-01475-7

The surge of fast-spreading SARS-CoV-2 mutated variants highlights the need for fast, broad-spectrum strategies to counteract viral infections. In this work, we report a physical barrier against SARS-CoV-2 infection based on an inhalable bioadhesive hydrogel, named spherical hydrogel inhalation for enhanced lung defence (SHIELD). Conveniently delivered via a dry powder inhaler, SHIELD particles form a dense hydrogel network that coats the airway, enhancing the diffusional barrier properties and restricting virus penetration. SHIELD's protective effect is first demonstrated in mice against two SARS-CoV-2 pseudo-viruses with different mutated spike proteins. Strikingly, in African green monkeys, a single SHIELD inhalation provides protection for up to 8 hours, efficiently reducing infection by the SARS-CoV-2 WA1 and B.1.617.2 (Delta) variants. Notably, SHIELD is made with food-grade materials and does not affect normal respiratory functions. This approach could offer additional protection to the population against SARS-CoV-2 and other respiratory pathogens.

	Description
sense Example: Hs-LAG3-sense	Standard probes for RNA detection are in antisense. Sense probe is reverse complent to the corresponding antisense probe.
Intron# Example: Mm-Htt-intron2	Probe targets the indicated intron in the target gene, commonly used for pre-mRNA detection
Pool/Pan Example: Hs-CD3-pool (Hs-CD3D, Hs-CD3E, Hs-CD3G)	A mixture of multiple probe sets targeting multiple genes or transcripts
No-XSp Example: Hs-PDGFB-No-XMm	Does not cross detect with the species (Sp)
XSp Example: Rn-Pde9a-XMm	designed to cross detect with the species (Sp)
O# Example: Mm-Islr-O1	Alternative design targeting different regions of the same transcript or isoforms
CDS Example: Hs-SLC31A-CDS	Probe targets the protein-coding sequence only
EnEm	Probe targets exons n and m
En-Em	Probe targets region from exon n to exon m
Retired Nomenclature
tvn Example: Hs-LEPR-tv1	Designed to target transcript variant n
ORF Example: Hs-ACVRL1-ORF	Probe targets open reading frame
UTR Example: Hs-HTT-UTR-C3	Probe targets the untranslated region (non-protein-coding region) only
5UTR Example: Hs-GNRHR-5UTR	Probe targets the 5' untranslated region only
3UTR Example: Rn-Npy1r-3UTR	Probe targets the 3' untranslated region only
Pan Example: Pool	A mixture of multiple probe sets targeting multiple genes or transcripts

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