Characterization of the human aqueous humour proteome: A comparison of the genders

Natarajan Perumal,Norbert Pfeiffer,Matthias Steinicke,Caroline Manicam,Sebastian Funke,Franz H. Grus,Jon M. Jacobs

doi:10.1371/journal.pone.0172481

Abstract

Aqueous humour (AH) is an important biologic fluid that maintains normal intraocular pressure and contains proteins that regulate the homeostasis of ocular tissues. Any alterations in the protein compositions are correlated to the pathogenesis of various ocular disorders. In recent years, gender-based medicine has emerged as an important research focus considering the prevalence of certain diseases, which are higher in a particular sex. Nevertheless, the inter-gender variations in the AH proteome are unknown. Therefore, this study endeavoured to characterize the AH proteome to assess the differences between genders. Thirty AH samples of patients who underwent cataract surgery were categorized according to their gender. Label-free quantitative discovery mass spectrometry-based proteomics strategy was employed to characterize the AH proteome. A total of 147 proteins were identified with a false discovery rate of less than 1% and only the top 10 major AH proteins make up almost 90% of the total identified proteins. A large number of proteins identified were correlated to defence, immune and inflammatory mechanisms, and response to wounding. Four proteins were found to be differentially abundant between the genders, comprising SERPINF1, SERPINA3, SERPING1 and PTGDS. The findings emerging from our study provide the first insight into the gender-based proteome differences in the AH and also highlight the importance in considering potential sex-dependent changes in the proteome of ocular pathologies in future studies employing the AH.

Highlights

Proteomic studies of the aqueous humour (AH) has been a subject of much interest owing to the multiple physiological roles of the AH in maintaining proper functionality of the ocular system
The characterization of the human AH proteome saw massive progress in the last decade, especially instrumental in defining specific changes associated with the pathogenesis of myriad eye diseases, such as primary open angle glaucoma (POAG) [6,7,8], primary congenital glaucoma [9], cataract [1, 2, 5, 10], myopia [11], Coats’ disease [12], glaucoma with pseudoexfoliation syndrome [13], keratoconus [14], branch retinal vein occlusion (BRVO) [15], acute corneal rejection [16] and age-related macular degeneration (AMD) [17, 18]
Since these experiments were performed without any depletion steps, several thick protein bands were visualized in the molecular weight region of 49 to 70 kDa that represent albumin

Summary

Introduction

Proteomic studies of the aqueous humour (AH) has been a subject of much interest owing to the multiple physiological roles of the AH in maintaining proper functionality of the ocular system. Gender differences in the aqueous humour proteome tissues and has active participation in the immune response against invading pathogens and inflammation [1,2,3,4,5]. The gender-specific differences in AH proteome are yet to be explored. Since the AH is an ultrafiltration of blood, we hypothesize that there may be gender-specific differences in the AH proteome

Methods

Results

Conclusion