Mohamed Nasir Nurdiena, Hiji Jumriah, Jayapalan Jaime Jacqueline, Hashim Onn Haji
Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia.
University of Malaya Center for Proteomics Research, Faculty of Medicine, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia.
PeerJ. 2020 Jan 30;8:e8248. doi: 10.7717/peerj.8248. eCollection 2020.
Most human hairs collected at old crime scenes do not contain nuclear DNA and are therefore of less value for forensic investigations. In the present study, hair shaft proteins were extracted from 40 healthy subjects between the ages of 21 to 40 years and profiled using gel electrophoresis-based proteomics to determine if they can be used to distinguish gender and ethnicity.
Extraction of the human hair shaft proteins was performed using a newly developed alkaline solubilisation method. The extracts were profiled by 2-dimensional electrophoresis and resolved protein spots were identified by mass spectrometry and queried against the human hair database. The study was then followed-up by immunoblotting of the identified hair shaft keratin of interest using commercially available antibodies.
Separation of the human hair shaft proteins by 2-dimensional electrophoresis generated improved and highly resolved profiles. Comparing the hair shaft protein profiles of 10 female with 10 male subjects and their identification by mass spectrometry and query of the human hair database showed significant altered abundance of truncated/processed type-II keratin peptides K81 (two spots), K83 (one spot) and K86 (three spots). The 2-dimensional electrophoresis profiling of 30 hair shaft samples taken from women of similar age range but from three distinctive ethnic subpopulations in Malaysia further showed significant altered abundance of one type-I and four type-II truncated/processed keratin peptides including K33b, K81, K83 and K86 (2 spots) between at least two of the ethnic groups. When a followed-up immunoblotting experiment was performed to detect the relative expression of the K86 peptides using commercialised antibodies, similar trends of expression were obtained. The present data, when taken together, demonstrated the potential use of keratin peptide signatures of the human hair shaft to distinguish gender and ethnicity although this needs to be further substantiated in a larger scale study.
在旧犯罪现场收集的大多数人类毛发不包含核DNA，因此对法医调查的价值较小。在本研究中，从40名年龄在21至40岁之间的健康受试者中提取毛发轴蛋白，并使用基于凝胶电泳的蛋白质组学进行分析，以确定它们是否可用于区分性别和种族。
使用新开发的碱性溶解方法提取人类毛发轴蛋白。提取物通过二维电泳进行分析，分离出的蛋白质斑点通过质谱鉴定，并与人类毛发数据库进行比对。然后使用市售抗体对鉴定出的感兴趣的毛发轴角蛋白进行免疫印迹分析，对该研究进行后续跟进。
通过二维电泳分离人类毛发轴蛋白产生了改进的、高度分辨的图谱。比较10名女性和10名男性受试者的毛发轴蛋白图谱，并通过质谱鉴定和查询人类毛发数据库，结果显示截短/加工型II角蛋白肽K81（两个斑点）、K83（一个斑点）和K86（三个斑点）的丰度有显著变化。对从马来西亚年龄范围相似但来自三个不同种族亚群体的女性中采集的30个毛发轴样本进行二维电泳分析，结果进一步显示，至少两个种族之间一种I型和四种II型截短/加工角蛋白肽（包括K33b、K81、K83和K86（两个斑点））的丰度有显著变化。当使用商业化抗体进行后续免疫印迹实验以检测K86肽的相对表达时，获得了相似的表达趋势。综合目前的数据表明，人类毛发轴的角蛋白肽特征有可能用于区分性别和种族，尽管这需要在更大规模的研究中进一步证实。
