Advanced Research Laboratory, Hoyu Co., Ltd., Aichi, Japan.
Advanced Research Laboratory, Hoyu Co., Ltd., Aichi, Japan.
Biochem Biophys Res Commun. 2021 Jan 8;535:19-24. doi: 10.1016/j.bbrc.2020.12.033. Epub 2020 Dec 16.
Histamine-producing cells include storage-type cells (e.g., mast cells and basophils), which store histamine intracellularly, and inducible-type cells (e.g., keratinocytes and macrophages), which induce histidine decarboxylase (HDC, a key enzyme for histamine biosynthesis) activity but do not have a storage pool of histamine. Most of the studies focused on identifying HDC-expressing cells by using cultured cells, and few on investigating the localization of HDC by using skin tissues. Hence, this study conducted immunohistochemical studies using human healthy skin samples. HDC-positive and cytokeratin 14 (a marker of basal keratinocytes)-negative cells were present around the basal layer of the epidermis. These cells did not immunohistochemically react with mast cell tryptase but expressed tyrosinase (a key enzyme for melanin biosynthesis) and microphthalmia-associated transcription factor (MITF, a transcription factor controlling the expression of tyrosinase genes). Melanin granules were clearly observed around HDC-positive and MITF-positive cells. Moreover, HDC mRNA and protein were both detected in cultured normal human epidermal melanocytes. In conclusion, HDC-positive and cytokeratin 14-negative cells around the basal layer of the epidermis are melanocytes.
产生组织胺的细胞包括储存型细胞（例如肥大细胞和嗜碱性粒细胞），其将组织胺储存于细胞内，和诱导型细胞（例如角质形成细胞和巨噬细胞），其诱导组氨酸脱羧酶（HDC，组织胺生物合成的关键酶）活性但没有组织胺的储存池。大多数研究集中于使用培养细胞来鉴定表达 HDC 的细胞，而使用皮肤组织来研究 HDC 定位的研究较少。因此，本研究使用人健康皮肤样本进行了免疫组织化学研究。HDC 阳性和细胞角蛋白 14（基底角质形成细胞的标志物）阴性细胞存在于表皮的基底层周围。这些细胞与肥大细胞 tryptase 没有免疫组织化学反应，但表达酪氨酸酶（黑色素生物合成的关键酶）和小眼畸形相关转录因子（MITF，控制酪氨酸酶基因表达的转录因子）。在 HDC 阳性和 MITF 阳性细胞周围可以清楚地观察到黑色素颗粒。此外，在培养的正常人表皮黑素细胞中均检测到 HDC mRNA 和蛋白。总之，表皮基底层周围 HDC 阳性和细胞角蛋白 14 阴性的细胞是黑素细胞。
