Fig. 1.

Cyclic stretch increases cytosolic protein thiol oxidation via mitochondrial complex III to induce a persistent pulmonary hypertension of the newborn (PPHN) pulmonary artery smooth muscle cell (PASMC) phenotype. Control and PPHN PASMC were infected with an adenovirus expressing reduction-oxidation-sensitive green fluorescent protein (roGFP) in the cytosol (A) or mitochondrial matrix (B). After 48 h, control cells were subjected to 24-h cyclic stretch at 1 Hz and 15% elongation. The extent of roGFP oxidation in lysates was determined by flow cytometry, and the percent oxidation determined by fully oxidizing and fully reducing the probe. Between 5,000 and 20,000 roGFP-positive cells were quantified for each sample. A and B: RoGFP oxidation in static and stretch PPHN PASMC is included for comparison. C: RoGFP-infected control PASMC were treated with vehicle (Veh) or 1 μM myxothiazol (Myx) to inhibit complex III and then exposed to 24-h stretch (Str), as above. Stat, static. D: PASMC were treated with Veh or 1 μM Myx for 24 h and then fixed and nuclei stained with DAPI. Values are means ± SE; n ≥ 3. *P < 0.05 vs. control static (A and B) or control Stat Veh (C). †P < 0.05 vs. Str Veh. UTD, ???.