Journal: Science Advances

Article Title: Three-dimensional heart extracellular matrix enhances chemically induced direct cardiac reprogramming

doi: 10.1126/sciadv.abn5768

Figure Lengend Snippet: ( A ) Representative images and patterns of Ca 2+ fluorescence visualized using Fluo-4 AM as an intracellular Ca 2+ indicator (scale bars, 20 μm). ( B ) Calcium imaging of spontaneously beating CiCMs (top) and CiCMs electrically stimulated at 1 Hz (bottom) (scale bars, 10 μm). ( C ) Average time between Ca 2+ transients ( n = 4 to 7; ** P < 0.01 versus spontaneous group, two-tailed t test). ( D to I ) Field potential analysis using MEA on day 16 of culture. (D) Bright-field image of a 3D HEM CiCM construct on 64 planar microelectrodes (scale bar, 200 μm) and (E) representative field potential traces from a single well. (F) A representative extracellular field potential waveform obtained from an electrode on the MEA plate. (G) Field potential parameters of 3D HEM CiCMs ( n = 8). (H) The effect of isoproterenol on the field potentials of 3D HEM CiCMs. Representative field potential waveforms before drug (control) and in the presence of 10 to 1000 nM isoproterenol (ISO). (I) BPM change of 3D HEM CiCMs in the presence of multiple doses of isoproterenol (normalized to the control group) ( n = 3; ** P < 0.01 versus control group by one-way ANOVA followed by Dunnett’s test). ( J ) Representative APs of the 3D HEM CiCMs after 18 days of chemical reprogramming and isolated neonatal cardiomyocyte (nCM). ( K ) Comparison of AP parameters of 3D HEM CiCMs with nCMs, including maximum diastolic potential (MDP), AP amplitude (APA), maximum upstroke velocity (dV/dt max ), and beating frequency (BF) ( n = 8). All data are expressed as the means ± SD.

Article Snippet: MEA measurements were performed using the Maestro MEA system with the 12-well MEA plate from Axion BioSystems Inc. (Atlanta, GA, USA).

Techniques: Fluorescence, Imaging, Two Tailed Test, Construct, Isolation