Reduced pulmonary CFTR expression is a hallmark of the HF
lung
The accumulation of non-alveolar classically-activated macrophages
(CD80+ SiglecF-) associated with
markedly higher TNF-α protein levels in HF compared to sham lungs
(Fig. 3a ). Since TNF-α potently reduces CFTR surface expression
in different cell types [5, 29], we determined cell surface-specific
CFTR expression in the lung by performing a flow cytometry-based CFTR
staining approach with an antibody targeting membrane-associated, mature
CFTR protein [30] (Supplemental Table 1 ). The overall
number of surface-CFTR+ cells was significantly
reduced in HF lungs (Fig. 3b, c ), which coincided with
significantly lower expression levels of membrane-bound CFTR assessed by
Western blotting (Fig. 3d ).