Protein/DNA ratio.

We also compared protein/DNA ratio in ASM derived from hORMDL3^{Myh11eGFP-cre} with that of WT mice as an index of ASM hypertrophy as described (54). Protein/DNA ratio has been used as an indicator of cellular hypertrophy, as with cell size increase (i.e., hypertrophy), more protein synthesis occurs (relative to DNA synthesis) to meet the increased architectural and functional demands of the growing cell (55). To determine ASM hypertrophy, total protein to DNA content was assessed in WT and hORMDL3^{Myh11eGFP-cre} ASM cells seeded at a density of 2 × 10⁵ cells/well for 2 days. Protein and DNA were then isolated using Qiagen AllPrep kit, and total protein and DNA content was quantified using a NanoDrop Spectrophotometer (Thermo Fisher Scientific).