Proteomic profiling of hair proteome and its potential antimicrobial activity

Antimicrobial proteins/peptides (AMPs) are a promising class of antimicrobial agents which play an important role in host defence systems. In addition, they aid in apoptosis, wound healing and immune modulation. Skin and hair form an impervious barrier to pathogens and act as the first line of defence. Maintenance of skin and hair microbiota leads to the establishment of effective antimicrobial defence and microflora containment as the vital part of the skin’s innate immune system. Previous studies reveal the presence of AMP’s from the skin, but no activity has been reported from hair till now. Hair proteomics studies have shown the presence of known AMP’s like histones, RNAse7 and psoriasin which indicates possible AMP activity in the hair. Hence, this project aims to (1) optimise hair protein extraction methods, (2) identify and fractionate hair proteins; (3) evaluate the antimicrobial properties of hair protein fractions. High-throughput mass spectrometry analyses and reverse phase high-performance liquid chromatography (RP-HPLC) were carried out to identify and fractionate AMP enriched fractions which were analysed for antimicrobial activity. Two different types of hair protein enrichment analyses were performed, extraction using urea and extractions using sodium dodecyl sulfate (SDS) which were known as KAP extraction and SDS extractions respectively. Mass spectrometry revealed the presence of 115 common proteins, 65 were unique to KAP, 124 to SDS I and 69 to SDS II extractions respectively. Several histone isomers were identified in each method, of which H1, H2A, H2B, H4 from KAP and H2B, H3, H4 from SDS extractions were validated by Western blotting. AMP activity against E.Coli was observed in 15-18 minute fractions of KAP extraction analysed on HPLC. Subsequently, dot blot analyses confirmed the presence of histones. Hence, it was concluded that hair proteome contained promising antimicrobial activity probably due to the presence of histones. Further studies should be carried out to purify and characterize histones by mass spectrometry, electrophoretic methods and analyse the mode of action of the observed antimicrobial activity.Bachelor of Engineering (Materials Engineering