COMT-IN-1

Human pluripotent stem cells are directed toward midbrain dopaminergic neurons by first inducing a neural floor-plate-like progenitor state, then patterning cells with ventralizing SHH signaling and midbrain/WNT-FGF cues, and finally maturing progenitors into neurons expressing dopaminergic markers such as TH, NURR1/NR4A2, PITX3, DAT/SLC6A3, VMAT2/SLC18A2, GIRK2/KCNJ6, FOXA2, LMX1A, and EN1. The main readouts are loss of pluripotency, acquisition of FOXA2+/LMX1A+ midbrain floor-plate progenitors, emergence of βIII-tubulin+/MAP2+ neurons, and production of TH+ dopaminergic neurons with molecular, dopamine-release, and electrophysiological features of midbrain dopaminergic identity.

TEER measures electrical resistance across epithelial or endothelial monolayers cultured on permeable supports, and the readout reflects ionic conductance through the cell barrier, especially the paracellular pathway regulated by junctional integrity. TEER can be measured without destroying the monolayer and is commonly used before or during transport, permeability, barrier-disruption, and barrier-maturation experiments. TEER values are influenced by biological maturation and technical conditions; reported factors include temperature, medium formulation, passage number, electrode geometry, membrane properties, and junctional length during early monolayer maturation. Therefore, TEER should be interpreted with blank-insert subtraction, area normalization, repeated readings, and, when possible, orthogonal barrier readouts such as FITC-dextran flux or tight-junction staining.