Li Yongwei, Chen Feifei, Lin Fuquan, Guan Cuiping, Wei Xiaodong, Wan Yinsheng, Xu Aie
Department of Dermatology, the Third People's Hospital of Hangzhou, Hangzhou 310009, PR China.
Int J Mol Med. 2009 May;23(5):673-8. doi: 10.3892/ijmm_00000179.
It has been shown that the VIT1 gene is down-regulated in vitiligo melanocytes, but the expression of the VIT1 gene in melanocytes of Chinese patients with vitiligo and the potential function of VIT1 in pathogenesis of vitiligo are not as well known. In this study, we first compared VIT1 gene expression in melanocytes cultured from non-lesional skin of generalized vitiligo patients, normal melanocytes and melanomas in China. The cloned VIT1 ORF cDNA fragments were sequenced and then compared. VIT1 siRNAs were transfected into mouse B10BR melanocytes. The results from semi-quantitative RT-PCR demonstrated that the expression levels of VIT1 in non-lesional melanocytes from vitiligo patients are significantly lower than those in normal melanocytes. In contrast, the expression levels of VIT1 in melanoma are higher. The results also demonstrated that VIT1 is not a novel gene including a fragment of 81 bp flanking by consensus GT and AG sequences on the 5' and 3' ends, which is regarded as an intron. VIT1 without the extra intron is a known gene called FBXO11. Our findings revealed abnormal morphology by light and electron microscopes in FBXO11 siRNA transfected melancytes, which display large epithelioid perikaryon and stubby dendrites with occasional multidendricity as opposed to slender perikaryon and bipolar dendrites of controls. The electron microscopic observation indicated swelling mitochondria and endoplasmic reticulum (ER), and increased lysosomes and bubbles. Further, transfection of FBXO11 siRNA significantly promoted cell apoptosis. Collectively, this study provides comprehensive morphological proof of the relationship between dilation of ER and decreased levels of the FBXO11 gene in vitiligo melanocytes.
研究表明，白癜风黑素细胞中VIT1基因表达下调，但中国白癜风患者黑素细胞中VIT1基因的表达情况及其在白癜风发病机制中的潜在作用尚不明确。在本研究中，我们首先比较了中国泛发性白癜风患者非皮损处皮肤培养的黑素细胞、正常黑素细胞和黑素瘤中VIT1基因的表达。对克隆的VIT1开放阅读框（ORF）cDNA片段进行测序并比较。将VIT1小干扰RNA（siRNAs）转染至小鼠B10BR黑素细胞。半定量逆转录聚合酶链反应（RT-PCR）结果显示，白癜风患者非皮损处黑素细胞中VIT1的表达水平显著低于正常黑素细胞。相反，黑素瘤中VIT1的表达水平较高。结果还表明，VIT1不是一个新基因，其5'和3'端有一段81 bp的片段，两侧分别为保守的GT和AG序列，被视为一个内含子。去除额外内含子的VIT1是一个已知基因，称为FBXO11。我们的研究结果显示，在转染FBXO11 siRNA的黑素细胞中，光镜和电镜下均呈现异常形态，其核周体大且呈上皮样，树突短粗，偶有多分支，而对照组的核周体细长，树突为双极。电镜观察显示线粒体和内质网肿胀，溶酶体和空泡增多。此外，转染FBXO11 siRNA可显著促进细胞凋亡。总体而言，本研究为白癜风黑素细胞内质网扩张与FBXO11基因水平降低之间的关系提供了全面的形态学证据。
