A Metabolic View of Receptor Activation in Cultured Cells Following Cryopreservation

The effect of cryopreservation on agonist-induced receptor activation in mammalian cells was investigated with the Cytosensor microphysiometer, a biosensor that monitors cellular metabolic activity by measuring changes in extracellular pH. In this study, two different cell types—nonadherent TF-1 cells (from a human erythroleukemia patient) and adherent WT3 cells (CHO-K1 cells transfected with the m 1 muscarinic acetylcholine receptor)—were cryopreserved by freezing in a disposable cell capsule used in the microphysiometer. The recovery of metabolic activity by TF-1 cells was observed over ∼1 h following thawing. Responses of the TF-1 cells to granulocyte-macrophage colony-stimulating factor (GM-CSF) and platelet activating factor (PAF) were measured before cryopreservation and 90 min after thawing. The GM-CSF and PAF responses retained 71 ± 14% and 73 ± 10% of maximum stimulation, respectively. Post-thaw cholinergic stimulation of WT3 cells was 73 ± 9% of its level in similarly treated but unfrozen cells. Cryopreservation caused no detectable difference in desensitization of the response due to repeated application of carbachol. These results demonstrate the feasibility of pharmacological studies with cryopreserved cells in the microphysiometer and further suggest that the microphysiometer may be useful in exploring the biological consequences of cryopreservation in the early post-thaw period.