Journal: Signal Transduction and Targeted Therapy

Article Title: A biosafe mouse model for SARS-CoV-2 infection that more realistically simulates COVID-19 symptoms

doi: 10.1038/s41392-026-02640-5

Figure Lengend Snippet: SA-N-hACE2 mice are susceptible to SARS-CoV-2 ΔN/GFP-HiBiT infection. a Experimental design for intranasal infection. After TAM treatment, SA-N-hACE2 mice were infected either with 5 × 10 4 or 1 × 10 6 TCID 50 of SARS-CoV-2 ΔN/GFP-HiBiT. Tissue samples were collected at the indicated dpi. b Changes in the weights of the mice are shown ( n = 4 per group). c qRT‒PCR was used to quantify viral loads in tissues at 7 dpi ( n = 4 per group). The viral loads ( d ) and luminescence ( e ) were measured in the lungs collected at 2, 4, and 7 dpi ( n = 4 per group). f Immunofluorescence staining of lung sections at 2, 4, and 7 dpi was conducted using DAPI (blue) and an anti-GFP antibody (green) specific to GFP in SARS-CoV-2 ΔN/GFP-HiBiT. g – j Pathological changes observed using H&E staining in lung ( g ) and brain ( i ) tissues from SA-N-hACE2 mice challenged with 1 × 10 6 TCID 50 at 0, 2, 4, and 7 dpi. Pathology scores for the lungs ( h ) and brain ( j ) were calculated ( n = 4 per group). Data are presented as means ± SD. Statistical significance was determined using one-way ANOVA with Dunnett’s multiple comparisons test ( h ). ns not significant; * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001. ND not detected

Article Snippet: The samples were first immunostained with an anti-GFP antibody (Sino Biological, 13105-R208, 1:500) followed by an Alexa Fluor 488-conjugated secondary antibody (Thermo Fisher Scientific, A-11008, 1:1000).

Techniques: Infection, Immunofluorescence, Staining

Journal: Signal Transduction and Targeted Therapy

Article Title: A biosafe mouse model for SARS-CoV-2 infection that more realistically simulates COVID-19 symptoms

doi: 10.1038/s41392-026-02640-5

Figure Lengend Snippet: Sftpc-N-hACE2 mice are susceptible to SARS-CoV-2 ΔN/GFP-HiBiT infection. a Illustration of the protocol for intranasal infection with tissue samples collected at the indicated dpi. Sftpc-N-hACE2 mice were infected with 5 × 10 4 or 1 × 10 6 TCID 50 of SARS-CoV-2 ΔN/GFP-HiBiT. b Changes in the body weights of the mice are shown ( n = 4 per group). c Viral loads in the tissues obtained at 7 dpi were quantified via qRT‒PCR ( n = 4 per group). The viral loads ( d ) and luminescence ( e ) were measured in the lungs collected at 2, 4, and 7 dpi ( n = 4 per group). f Immunofluorescence staining of lung sections at 2, 4, and 7 dpi was conducted using DAPI (blue) and an anti-GFP antibody (green) specific to GFP in SARS-CoV-2 ΔN/GFP-HiBiT. g – j Pathological changes in the lungs ( g ) and brains ( i ) of Sftpc-N-hACE2 mice challenged with 1 × 10 6 TCID 50 at 0, 2, 4, and 7 dpi were assessed using H&E staining. Pathology scores for the lungs ( h ) and brains ( j ) are shown ( n = 4 per group). Data are presented as means ± SD. Statistical significance was determined using one-way ANOVA with Dunnett’s multiple comparisons test ( h ). ns not significant; * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001. ND not detected

Article Snippet: The samples were first immunostained with an anti-GFP antibody (Sino Biological, 13105-R208, 1:500) followed by an Alexa Fluor 488-conjugated secondary antibody (Thermo Fisher Scientific, A-11008, 1:1000).

Techniques: Infection, Immunofluorescence, Staining

Journal: Signal Transduction and Targeted Therapy

Article Title: A biosafe mouse model for SARS-CoV-2 infection that more realistically simulates COVID-19 symptoms

doi: 10.1038/s41392-026-02640-5

Figure Lengend Snippet: SARS-CoV-2 ΔN/GFP-HiBiT infection in Sftpc-N-hACE2 mice can lead to lethal disease. a The schematic outlines the procedure for infecting the mice with 5 × 10 6 TCID 50 of SARS-CoV-2 ΔN/GFP-HiBiT. At 0, 7, 10, 14, and 21 dpi, four mice were euthanized at each time point for sample collection. Mice that experienced a loss of more than 20% of their initial body weight were euthanized as a humane endpoint. Mice were monitored for body weight changes ( b ) and survival ( c ) ( n = 16). E gene copies in lung ( d ) and brain ( e ) tissues were quantified via qRT‒PCR. f – i Pathological changes were assessed using H&E staining in the lungs ( f ) and brains ( g ). Pathology scores for the lungs ( h ) and brains ( i ) were recorded ( n = 4 per group). j Immunofluorescence staining of brain sections was performed using DAPI (blue) and an anti-GFP antibody (green) specific to GFP in SARS-CoV-2 ΔN/GFP-HiBiT. k Immunofluorescence analysis was performed on brain sections from mock-infected mice, K18-hACE2 KI mice challenged with live SARS-CoV-2, and both SA-N-hACE2 and Sftpc-N-hACE2 mice exposed to SARS-CoV-2 ΔN/GFP-HiBiT. The sections were stained with anti-IBA1 (red) and anti-CD68 (green) antibodies. l Light-sheet imaging of cleared lung tissues from Sftpc-N-hACE2 mice at 7 dpi confirmed the distribution of SARS-CoV-2 N in lung epithelial cells and SARS-CoV-2 ΔN/GFP-HiBiT infection. Data are presented as means ± SD. Statistical significance was determined using one-way ANOVA with Dunnett’s multiple comparisons test ( h ). ns not significant; * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001. ND not detected

Article Snippet: The samples were first immunostained with an anti-GFP antibody (Sino Biological, 13105-R208, 1:500) followed by an Alexa Fluor 488-conjugated secondary antibody (Thermo Fisher Scientific, A-11008, 1:1000).

Techniques: Infection, Staining, Immunofluorescence, Imaging