Yan Nie, Helmholtz-Zentrum Institute of Active Polymers
The Response of Human Induced Pluripotent Stem Cells to Cyclic Cold Shock
Written by Arun Kumar
The external microenvironment is crucial in providing a homeostatic condition and a homing “niche” for the cells to survive and proliferate. When there is a sudden shift in this homeostasis, the cells could go under stress. Yan Nie and her colleagues from the Helmholtz-Zentrum Institute of Active Polymers are studying how cyclic cold stress (an extracellular environmental stress condition) can affect the properties of human-induced pluripotent stem cells (hiPSCs). The hIPSCs were exposed to either 37°C incubation or an intermittent cyclic 30 minute 10°C cold stress, cold stress, and the cellular response was measured after 24 hours.
Pluripotent stemness markers such as NANOG and SOX2 were examined using immunofluorescence staining. It confirms whether the stress condition is promoting the stem cells to undergo differentiation. SOX2 expression was higher in the hIPSCs exposed to the cyclic cold stress indicating that the stem cells might commit to ectodermal lineage differentiation. An upregulated F-actin shows that the cytoskeleton is remodified in the hIPSCs following cold stress. A small increase in Young’s modulus was observed in the cells exposed to cold stress which, Yan Nie suggests, might be due to the remodified actin cytoskeletal arrangement in the cell. Topographical analysis of the cellular surface using atomic force microscopy showed a significant increase in the roughness mean square (RMS) value between the normal and cyclic cold stress conditions. This result proves that there is a remodeled and decellularized extracellular matrix after undergoing cyclic cold stress. The data suggests that the maintenance of external conditions such as temperature is critical in stemness regulation of in vitro cell culture with induced pluripotent stem cells. Yan Nie says the result can help researchers better understand the potential of hIPSCs for therapeutic hypothermia.
Yan Nie's presentation is available through May 31, 2021.