The expression pattern of N‐acetyltransferase 1 in healthy human skin

BACKGROUND: N‐acetyltransferase 1 (NAT1) is an enzyme expressed among others in keratinocytes in human skin. NAT1 is important in the biotransformation of aromatic amines, an important example being p‐phenylenediamine (PPD), a hair dye molecule. Unoxidized PPD penetrates the skin and is N‐acetylated by NAT1. OBJECTIVES: To investigate in detail the expression pattern of NAT1 in human skin. MATERIALS AND METHODS: Cryosections obtained from healthy human skin were stained for NAT1 and expression patterns were observed. NAT1 double stainings were performed with antibodies against different cellular organelles to determine expression patterns. RESULT: A speckled, granular expression of NAT1 was seen predominantly in the stratum basale. NAT1 was expressed in a cytoplasmic pattern, perinuclear, and in the nucleus. No co‐localisation was seen with the selected cellular organelles. Local differences in NAT1 expression patterns were observed between donors and between different biopsies obtained from the same donor. CONCLUSIONS: NAT1 is expressed predominantly in the stratum basale and can be found in the cytoplasm, nucleus, and perinuclear in human skin. Further studies should be performed to investigate expression of NAT1 in a larger sample size.