Salivary Proteome Profile of Women during Fertile Phase of Menstrual Cycle as Characterized by Mass Spectrometry

Abstract

Objectives: Ovulation is such a critical physiological process that its noninvasive detection based on salivary constituents has several advantages in humans. Hence, the present study is proposed to identify the ovulatory-specific proteins in saliva in order to detect ovulation phase. Materials and Methods: Samples were collected from women volunteers. The procedure adopted was approved by the Institutional Human Ethical Committee (DM/2014/101/38), Bharathidasan University. The saliva samples were collected from thirty healthy female volunteers, with a prior written consent. One-way analysis of variance was used to calculate protein concentration and band intensity using SPSS 16 software (SPSS Inc., Cary, NC, USA). The salivary protein expression pattern during different phases of menstrual cycle was analyzed using gel-based high resolution-liquid chromatography-mass spectrometry/mass spectrometry and matrix-assisted laser desorption ionization-time of flight/time of flight. Further, bioinformatics tools were adopted to annotate the proteins identified at various phases of menstrual cycle. Results: As many as 530 proteins showed up in the saliva during ovulatory phase, whereas there were only 251 proteins identified during postovulatory phase. The functional annotation of salivary proteins revealed that the proteins got assigned to the class of “extracellular proteins” which are concerned with regulatory functions. The 16 unique and/or differentially expressed protein spots appeared during ovulatory phase, among which Cystatin-S, Prolactin-inducible protein, Cystatin-A, Cystatin-SN, BPI fold-containing family A member 2, Alpha-tubulin N-acetyltransferase 1, Carbonic anhydrase-6, Protein LEG1 homolog, Hemoglobin subunit beta, and Pancreatic alpha-amylase were identified. Conclusion: Total salivary proteome profile has been listed with respect to various phases of menstrual cycle. Among the protein listed, Cystatin-S offers a biomarker protein and/or indicator of ovulatory phase. However, extensive validation is required before arriving to a candidate bio-marker protein.

Ectopic pregnancy: search for biomarker in salivary proteome

“…Human saliva contains several Cystatin family proteins, including Cystatin-A, Cystatin-B, Cystatin-C, Cystatin-D, Cystatin-S, Cystatin-SA and Cystatin-SN 63 . Particularly appearance of Cystatin-S, a cysteine protease inhibitor, is prominent during the ovulatory phase 28 . However, in the present study, Cystatin-A appeared during REP condition.…”

“…Thus, salivary proteins have been recommended as biomarkers to predict disease conditions such as Sjogren’s syndrome 19 , lung cancer 20 , oral cancer 21 , several systemic diseases 22 , HIV infection 23 , 24 , dental pellicle development 25 , hyperglycemia 26 , etc. Recently, it has been reported that salivary hormones and proteins have the potential to predict ovulation in women 27 , 28 . Saliva offers advantages such as easy non-invasive sampling, potential for large-scale studies, and the development of point-of-care platforms.…”

Potential biomarkers to predict return to fertility after discontinuation of female contraceptives—looking to the future

“…Some weaker but still promising candidates include serine protease inhibitor E2 (SERPINE2), which has been correlated with oocyte maturity and successful fertilization ( 214 ), and Cystatin S, isoforms of which were found to be heavily isolated to ovulatory vs. pre- or post-ovulatory phases ( 215 , 216 ).…”