016 Phenotypic Changes of a Monocyte Cell Line depend on the Culture Temperature

Abstract

Although the body temperature is mainteined at around 37 °C, the temperature of skin, which is facing directly to external environment, is affected by external climate. Since epidermal Langerhans cells reside in upper most layers of skin, they must be affected with temperature shift. But most of the in vitro experiments are conducted at 37 °C. In this study, threfore, the phenotypic changes of Langerhans cells were examined using a model cell line, THP-1 cells. Since the skin surface temperture goes down to 25 °C when people go in to a room at 10 °C, we chose the culture temperature at 29 °C, 33 °C, and regular 37 °C. The proliferation rate declined as temperature went down. The amount of RNA extracted from the same number of cells cultured at lower temperature was smaller than at 37 °C. These results suggest that cellular activity is lower at lower temperature. However, when gene expression was examined, some specific genes were detected at lower temperature, including inhibitor of NFκB, inhibitor of growth family2, B cell anti-translocator gene antiproliferative, while inflammatory genes were expressed at 37 °C, demonstrating that cells are not simply inactive but actively responding to lower temperature. The expression of CD86 examined by flowcytometry was same or a little bit lower at lower temperature compared to 37 °C, but higher after stimulation with dinitrochlorobenzene. These results suggest that epidermal Langerhans cells actively stay quiet at regular physiological condition. These results anyway tell us to consider the culture condition of in vitro experimants when extraporating to in vivo.