Figure 2.

The highly connected olfactory cortex shows a robust inflammatory response following SARS-CoV-2 infection

(A and B) Unbiased 3D microscopic quantification shows a significant increase in astrocyte recruitment (GFAP+) following SARS-CoV-2 infection.

(C and E) In addition, a robust increase in general (Iba1) and activated (HLA-DR) microglia markers are also associated with aging.

(F) HLA-DR+ reactive microglia were also found associated with degraded myelin basic protein (dgMBP), resulting in reduced normal myelin basic protein (MBP) expression in aged-infected animals in comparison with aged controls.

(G) To further analyze neuron-microglia dynamics across the experimental groups, we combined general markers for neurons (pan-NF) and microglia (Iba1) with the post-synaptic marker PSD95 in the primary olfactory region.

(H–L) Analysis of PSD95 puncta density (H), microglial total cell volume (I), pan-NF microglial engulfment (J), microglia soma volume (K), and PSD95 microglial engulfment (L) demonstrates a robust phagocytic response observed in the brain following SARS-CoV-2 infection, especially in the older infected population.

Scale bars, 200 μm (A–F), 10 μm, and 5 μm (3D) (G). ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001, one-way ANOVA, Tukey’s post hoc test. Numerical data are represented as mean ± SEM.

See also Figures S4–S7 and Video S1.