Research Article

Immunolocalization of NLRP3 Inflammasome in Normal Murine Airway Epithelium and Changes following Induction of Ovalbumin-Induced Airway Inflammation

Figure 3

Activation of caspase-1 in inflamed airway epithelium of OVA-treated mice. Antibodies specific to cleaved ends of caspase-1 P20 or P10 subunits were employed to detect activation of caspase-1 in mouse lung tissue. (a) The normal airway epithelium typically expressed little active caspase-1. (b) In the inflamed airway, the swollen epithelium (arrowheads) labelled positively for active caspase-1 as shown by the punctate fluorescence of P20 near the apical surface. (c) and (d) Adjacent serial sections of an inflamed lung stained for antibodies to P20 and P10, respectively, revealed the same punctate patterns of caspase-1 activation near the apical surface. (e–g) In serial sections of an inflamed lung, fluorescence of P20 active caspase-1 antibody (e, red) was inhibited nearly completely by preabsorption of the antibody with the relevant immunogen peptide (f), to a level comparable to that of the conjugate alone control (g). Blue: DAPI counterstaining of nuclei. Images (a-b) are representative of results from P20 staining experiments on multiple sections obtained from 8 control saline-treated mice and 8 OVA-treated mice. Colocalization of P20 and P10 staining (c-d) and P20 peptide blocking experiments (e-f) were carried out on serial sections obtained from 4 inflamed lungs. Scales are in microns.
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