Fig. 4

ACE2 immunosignal is strong in mouse microvessels, but also found in neurons in human brain extracts. A, F Immunoblotting detection of ACE2 in human (parietal cortex) A and mouse (whole brain) F vascular fractions “Va”, compared to postvascular parenchymal samples depleted in vascular cells “P” and total homogenates “T”. SDS-PAGE was performed on a 4–20% acrylamide gradient gel. For comparison purposes, synaptophysin (synaptic/neuronal marker), Claudin5 (endothelial marker), and PDGFRβ (a marker of mural cells, including pericytes), are also shown. In the mouse brain, ACE2 is highly enriched in microvessels compared to the postvascular fraction, different to what is observed in the human A, F. B–E, G, H Representative immunostaining of ACE2 (green) in human B–E and murine cerebrovascular fractions G, H, with collagen IV (endothelial marker) in red B, D, G, H or blue C, E, as well as NeuN (neuronal marker) in red C, E and DAPI (nuclei) in blue B–H. In human samples, ACE2 staining is most frequently observed in neurons, whereas ACE2 staining is concentrated in murine microvessels. Red arrows point to ACE2 + /NeuN + cells, blue arrows to ACE2 + /NeuN- cells, and green arrows to erythrocytes. ACE2 antibodies: rb mAb #ab108252 A, F, rb pAb #HPA000288 B, D, G and #35–1875 C, E, H. Scale bar: 10 µm. ACE2 Angiotensin-Converting Enzyme 2, Coll IV Collagen IV Coloc Colocalization, NeuN Neuronal nuclear protein, PDGFRβ Platelet Derived Growth Factor Receptor Beta. mAb Monoclonal antibody, pAb Polyclonal antibody