Differential Temperature-Induced Responses in Immortalized Oral and Skin Keratinocytes

The epidermis of the skin and oral mucosa is constantly exposed to various environmental stimuli, including temperature changes. In particularly extreme conditions, such as excess heat or cold, significant injury may occur. Oral and skin keratinocytes exhibit tissue-specific differences in wound healing outcomes and the transcriptomic response to injury. This study investigated if skin and oral keratinocytes also have differential responses to heat- and cold-induced injury. Oral keratinocytes (TIGKs) were found to exhibit an enhanced viability following heat-induced injury compared to skin keratinocytes (HaCaTs). However, there were no discernible differences between skin and oral keratinocyte viability following cold-induced injury. To examine the transcriptomic differences between skin and oral keratinocytes in response to temperature-induced injury, we generated an mRNA-sequencing gene expression dataset. Differentially expressed genes (DEGs) including heat shock proteins (HSPs) were identified between HaCaTs and TIGKs at baseline (37 °C) and after heat- (60 °C) or cold-induced (-25 °C) injury. Our comparative analyses suggest that skin and oral keratinocytes exhibit transcriptomic differences at baseline and in their responses to heat or cold exposure. The enhanced heat tolerance of TIGKs relative to HaCaTs may be due to an advantageous expression of a subset of HSPs at baseline in TIGKs. Our work also provides a source of skin and oral keratinocyte gene expression data following heat- and cold-induced injury that can be used for future analyses.