Figure 1.

Progesterone (P4) receptor (PR) is expressed in cilia of airway epithelial cells. (A) Lung tissue from lung transplant donors of indicated sex immunostained for PR (red) and cilia marker, acetylated α-tubulin (α-tub; green), overlayed with differential interference contrast microscopy images show airway expression of PR in cilia. (B) Representative high-power images from (A) are shown. Rabbit IgG was substituted for anti-PR antibody in samples shown in the far right panel. Image detail shows PR expression in the proximal cilia (insets, middle panels). Images are representative of at least three samples from each sex. (C) Expression of PR in RNA isolated from human tracheal epithelial cell (hTEC) preparations relative to that in T-47D and SW480 cell lines. Shown are the mean (±SD) of PR in hTEC preparations derived from three different male and female donors, normalized to glyceraldehyde 3-phosphate dehydrogenase. (D) Protein blot analysis for PR-A and -B isoforms in hTECs from four different donors. (E) PR expression in cilia of fully differentiated hTEC preparation (male, air–liquid interface [ALI] Day 70) immunostained as in (A), viewed en face. Inset shows PR expression in hTECs sectioned from cells on membrane. Scale bars, 100 μm (A), 30 μm (B), 10 μm (E).