Presence of amplifiable mRNA in acellular hair shafts: Utilization to analyze gene expression profiles of black and white hairs

Background We postulated that hair shafts preserve amplifiable messenger RNAs (mRNAs) and that these mRNAs could be utilized to characterize phenotypic differences in hairs at the gene expression level. Objectives This study aimed to prove the presence of amplifiable mRNAs in the hair shaft and then to utilize them to characterize black and white hairs at the gene expression level. Methods RNAs were extracted from black and white scalp hair shafts and amplified by quantitative real-time polymerase chain reaction (qRT-PCR). Microarray analysis was performed using T7 RNA polymerase-amplified mRNAs derived from the hair shaft to examine the gene expression profiles of black and white hairs. Results We showed that hair shaft RNAs contained trace amounts of mRNAs and concluded that the acellular hair shaft contained mRNAs usable for microarray analysis. We termed the mRNA "fossil mRNA" (fmRNA) in this study. Totals of 10 and 2% of the detected genes were expressed at levels more than two-fold higher in black and white hairs compared with white and black hairs, respectively. We selected five genes and examined their expression levels in five donors by qRT-PCR. Among them, only hypothetical protein (L1H3 region) human was found to be expressed at 2.69±1.81 (relative ratio) in black hairs. Conclusions We demonstrated that the scalp hair shaft conserves fmRNAs which are probably remnants that have been expressed during hair differentiation. Consequently, fmRNA is expected to be a useful source of information for the study of phenotypic changes in hairs at the molecular level.