Journal: Circulation Research
Article Title: Cyclin D-CDK4 Disulfide Bond Attenuates Pulmonary Vascular Cell Proliferation
doi: 10.1161/CIRCRESAHA.122.321836
Figure Lengend Snippet: Oxidation decreases cyclin D-CDK4 (cyclin-dependent kinase) substrate phosphorylation and induces G1 phase cell cycle arrest. A , Oxidation of human pulmonary arterial smooth muscle cells (HPASMCs), induced by acute H 2 O 2 treatment, decreased. Rb (retinoblastoma) phosphorylation at S780, S795, or S807-811, and total Rb were detected by immunoblotting under reducing conditions. B , Quantification of Rb phosphorylation, normalized to total Rb. As the data sample size with an n<6 cannot be reliably tested for normality, P values are calculated using a nonparametric Kruskal-Wallis test followed by Dunn post hoc multiple comparisons to compare Rb phosphorylation in response to H 2 O 2 with the 0 µmol/L control (n=5 independent experiments); the results are shown as means±SEM. C , Histograms show cell cycle analysis using flow cytometry of propidium iodide-stained HPASMCs. Continuously cycling cells were maintained in DMEM growth medium (10% FBS; upper left), while G0/1 phase synchronized cells were maintained in starvation media (0.1% FBS) for 40 hours (upper right). Synchronized cells were stimulated to enter the cell cycle with 10% FBS alone for 24 hours (middle left), FBS plus 50 µmol/L H 2 O 2 for 24 hours (middle right), FBS plus DMSO vehicle (bottom left), or FBS plus 10 µmol/L palbociclib for 24 hours (bottom right). The proportion of cells in each phase of the cell cycle at this time point was analyzed by the Watson Pragmatic cell cycle model and an average from 4 to 5 independent experiments is provided. D , H 2 O 2 causes G1 phase cell cycle arrest. Graph shows the proportion of synchronized cells in each cell cycle phase with time after stimulation with 10% FBS alone (solid lines) or 10% FBS plus 50 µmol/L H 2 O 2 (dashed lines). P values are calculated using unpaired 2-tailed nonparametric Mann-Whitney U test to compare between vehicle and H 2 O 2 treatment in cell cycle phases at each time point (0 and 8 hours, n=5 experimental sample per group; 16, 24, or 28 hours, n=4 experimental samples per group); the results are shown as means±SEM. E , Proliferation of HPASMCs treated with 50 µmol/L H 2 O 2 or vehicle. Cells were seeded in xCELLigence real-time cell analysis (RTCA) E-plates at 3×10 4 cells/well in starvation media (0.1% FBS). After 40 hours, cells were stimulated with 10% FBS with or without H 2 O 2 . Proliferation rate of HPASMCs after treatment was quantified using area under the curve. As the data sample size with an n<6 cannot be reliably tested for normality, the P value is calculated using an unpaired 2-tailed nonparametric Mann-Whitney U test to compare between area under the curve for 0 and 50 µmol/L (n=4 independent experiments/ biological replicates per group, including n=2 performed in technical replicates for 0 µmol/L, altogether comprising n=6 replicates for 0 µmol/L and n=4 replicates for 50 µmol/L); the results are shown as means±SEM.
Article Snippet: Primary human pulmonary arterial smooth muscle cells (HPASMCs) were purchased from ScienCell Research Laboratories (No. 3110).
Techniques: Western Blot, Cell Cycle Assay, Flow Cytometry, Staining, MANN-WHITNEY