Potential use of human hair shaft keratin peptide signatures to distinguish gender and ethnicity

Nurdiena Mohamed Nasir; Jumriah Hiji; Jaime Jacqueline Jayapalan; Onn Haji Hashim

doi:10.7717/peerj.8248

Potential use of human hair shaft keratin peptide signatures to distinguish gender and ethnicity

PeerJ. 2020 Jan 30:8:e8248. doi: 10.7717/peerj.8248. eCollection 2020.

Authors

Nurdiena Mohamed Nasir¹, Jumriah Hiji², Jaime Jacqueline Jayapalan^{1

2}, Onn Haji Hashim^{1

2}

Affiliations

¹ Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia.
² University of Malaya Center for Proteomics Research, Faculty of Medicine, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia.

Abstract

Background: 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.

Methods: 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.

Results: 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.

Keywords: 2DE; Alkaline solubilisation method; Biomarkers; Human hair shaft proteins; Mass spectrometry.

Grants and funding

This work was supported by the Frontier Research Grant (FG017-17AFR) from the University of Malaya, Malaysia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.