HL-1 and NIH3T3 cells were initially plated at a density of 5 x 10 5 cells/well in 3.5 cm dishes. Next day cells were transfected with PDE5A isoforms GFP-tagged vectors. Twenty four hours later, cells were synchronized with 0.5 mM
L-Mimosine (Sigma-Aldrich, CA, USA). After 16 hrs, cells were washed with PBS and incubated in fresh culture media. At various times after release from the
L-Mimosine block the cells were treated with trypsin, harvested, and centrifuged at 2000 g for 5 min.
The pellets were washed with PBS and then centrifuged again. Cells were fixed with 1% w/v paraformaldehyde for 1hr at 4°C, then centrifuged for 5 min at 300 g; supernatant was removed by aspiration and pellets washed with PBS. For cell membrane solubilization, 1 ml 70% v/v ethanol was added to the cell pellet, and cell suspension incubated overnight at 4°C. Fixed cells were washed with PBS, centrifuged and incubated for 3 hr at room temperature with
propidium iodide/RNAse A solution (PI, 50 μg/mL, Sigma-Aldrich, CA, USA),
ribonuclease (1 mg/ml Sigma-Aldrich, CA, USA). The cell cycle distribution and DNA content were measured using a
CyAn cytofluorimeter (Dako). 5 x 10 3 cells were counted for each sample. The percentage of cells in different phases of the cell cycle was analyzed by FlowJo (TreeStar, Ashland, OR, USA).
Campolo F., Zevini A., Cardarelli S., Monaco L., Barbagallo F., Pellegrini M., Cornacchione M., Di Grazia A., De Arcangelis V., Gianfrilli D., Giorgi M., Lenzi A., Isidori A.M, & Naro F. (2018). Identification of murine phosphodiesterase 5A isoforms and their functional characterization in HL-1 cardiac cell line. Journal of cellular physiology, 233(1).