Figure 4.

Sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA2) expression in the epithelium of proximal and distal cystic fibrosis (CF) and non-CF airways. Immunohistochemical localization of SERCA2 was performed as described in Methods using identical conditions for non-CF and CF tissue. Left panel: Nonspecific IgG control. Right panel: SERCA2 staining in epithelium (arrowheads). SERCA2 staining was found predominantly in the epithelium of non-CF bronchi (n = 5 donors) (A) and bronchioles (C), and it was significantly less intense in the epithelium of CF airways (n = 5 donors) (B and D). (E) Quantitation of SERCA2 staining (SERCA2-IgG) in the non-CF and CF bronchi. The regions containing mucus were excluded during quantitation. For each tissue, two SERCA2 and two IgG-stained sections were analyzed, and 10 nonmucus areas per section were randomly selected for quantitation using Image-Pro Plus version 4.0 (Media Cybernetics, Silver Spring, MD). Similarly, SERCA2 staining in the non-CF and CF bronchioles was quantified (F).