Characterization of salivary protein during ovulatory phase of menstrual cycle through MALDI-TOF/MS

Advances in Research on Pig Salivary Analytes: A Window to Reveal Pig Health and Physiological Status

Saliva is an important exocrine fluid that is easy to collect and is a complex mixture of proteins and other molecules from multiple sources from which considerable biological information can be mined. Pig saliva, as an easily available biological liquid rich in bioactive ingredients, is rich in nucleic acid analytes, such as eggs, enzymes, amino acids, sugars, etc. The expression levels of these components in different diseases have received extensive attention, and the analysis of specific proteins, metabolites, and biological compositions in pig saliva has become a new direction for disease diagnosis and treatment. The study of the changes in analytes in pig saliva can provide a new strategy for early diagnosis, prognosis assessment, and treatment of diseases. In this paper, the detection methods and research progress of porcine salivary analytes are reviewed, the application and research progress of porcine salivary analytes in diseases are discussed, and the future application prospect is presented.

Diurnal variation in salivary progesterone in fertile Indian women

Research question

Is there a diurnal variation in salivary progesterone levels during menstrual cycle among Indian women?

Design

A longitudinal study was carried out to measure progesterone in saliva among small cross-sectional sample (n = 31) of fertile Indian women of reproductive age comprising young adults (18-25 years, n = 11), adults (26-38 years, n = 9) and middle aged (39-45 years, n = 11). Saliva samples were collected twice daily (morning and evening) across the entire menstrual cycle of 31 women.

Results

Mean ages at enrolment and menarche were 30.6 years and 13.6 years respectively. Fifty-five percent of the women were married. The menstrual cycle range was 20-40 days. After controlling for age and menstrual cycle length, statistically significant diurnal variation in progesterone levels was observed across menstrual cycles with high levels in the morning.

Conclusions

This is the first report on salivary progesterone in subjects with Indian ethnicity and could have clinical implications for designing point of care kits for menstrual cycle management, fertility and reproduction.

Identification of Estrus in Sows Based on Salivary Proteomics

The estrus cycle of multiparous Large White sows was divided into three stages to solve the problems of heavy workload and low accuracy of the traditional estrus identification method in pig production. Saliva protein was extracted from the oral saliva of multiparous sows. Label-free quantitative proteomics was used to detect salivary proteome, and MaxQuant software was used for quality control. Results showed that 246 proteins were identified in the three stages, where 40 proteins were significantly different (p < 0.05). The total proteins identified were enriched by STEM software and the protein function was annotated by using the ClueGO plug-in in the Cytoscape software. The results were enriched to eight different trends. The annotated items were related to protein synthesis and processing and estrogen response. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes enrichment analysis of differential proteins involved in the pathways and entries included oocyte meiosis, response to estradiol, and oogenesis. Further interaction analysis showed that an interaction occurred between P00355, F1SHL9, P28491, F1SDR7, F2Z558, F1RYY6, and F2Z5G3 proteins. The findings served as a basis for revealing the changes in salivary protein content in the sow estrus cycle and provided a reference for the development of an estrus identification kit/test strip in the next step.

Comparative Proteome Profiling of Saliva Between Estrus and Non-Estrus Stages by Employing Label-Free Quantitation (LFQ) and Tandem Mass Tag (TMT)-LC-MS/MS Analysis: An Approach for Estrus Biomarker Identification in Bubalus bubalis

Accurate determination of estrus is essentially required for efficient reproduction management of farm animals. Buffalo is a shy breeder and does not manifest overt signs of estrus that make estrus detection difficult resulting in a poor conception rate. Therefore, identifying estrus biomarkers in easily accessible biofluid such as saliva is of utmost interest. In the current study, we generated saliva proteome profiles during proestrus (PE), estrus (E), metestrus (ME), and diestrus (DE) stages of the buffalo estrous cycle using both label-free quantitation (LFQ) and labeled (TMT) quantitation and mass spectrometry analysis. A total of 520 proteins were identified as DEPs in LFQ; among these, 59 and four proteins were upregulated (FC ≥ 1.5) and downregulated (FC ≤ 0.5) during E vs. PE, ME, and DE comparisons, respectively. Similarly, TMT-LC-MS/MS analysis identified 369 DEPs; among these, 74 and 73 proteins were upregulated and downregulated during E vs. PE, ME, and DE stages, respectively. Functional annotations of GO terms showed enrichment of glycolysis, pyruvate metabolism, endopeptidase inhibitor activity, salivary secretion, innate immune response, calcium ion binding, oocyte meiosis, and estrogen signaling. Over-expression of SERPINB1, HSPA1A, VMO1, SDF4, LCN1, OBP, and ENO3 proteins during estrus was further confirmed by Western blotting. This is the first comprehensive report on differential proteome analysis of buffalo saliva between estrus and non-estrus stages. This study generated an important panel of candidate proteins that may be considered buffalo estrus biomarkers which can be applied in the development of a diagnostic kit for estrus detection in buffalo.

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

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.

Modulation of saliva pattern and accurate detection of ovulation using an electrolyte pre-deposition-based method: a pilot study

We developed an electrolyte pre-deposition-based saliva pattern modulation method to detect ovulation with high accuracy and reliability. Ovulation tests using human saliva have advantages in terms of the earlier ovulation detection and more convenient sample collection procedure; however, accuracy is low, which is a critical limitation given that the concentrations of salivary constituents can vary depending on the health status of the tested individual and subjective user judgement of the test result. In this study, we quantitatively analyzed saliva patterns according to the concentrations of electrolytes and proteins in the ovulation test and found that changes in the saliva pattern during the ovulatory period can be controlled by sodium chloride (NaCl) pre-deposition, which directly affects the accuracy of ovulation detection. The 100 nmol NaCl pre-deposition condition proved optimal, being two-fold more sensitive to changes in saliva pattern versus the non-pre-deposition condition (accuracy of ovulation detection = 66.6% and 33.3%, respectively). Although accuracy remained insufficient for actual applications compared to the urine-based ovulation detection method, we expect that the electrolyte pre-deposition method will greatly contribute to enhancing the performance of saliva-based ovulation detection tests, toward a commercially satisfactory level of accuracy.

Detection of ovulation, a review of currently available methods

The ability to identify the precise time of ovulation is important for women who want to plan conception or practice contraception. Here, we review the current literature on various methods for detecting ovulation including a review of point‐of‐care device technology. We incorporate an examination of methods to detect ovulation that have been developed and practiced for decades and analyze the indications and limitations of each—transvaginal ultrasonography, urinary luteinizing hormone detection, serum progesterone and urinary pregnanediol 3‐glucuronide detection, urinary follicular stimulating hormone detection, basal body temperature monitoring, and cervical mucus and salivary ferning analysis. Some point‐of‐care ovulation detection devices have been developed and commercialized based on these methods, however previous research was limited by small sample size and an inconsistent standard reference to true ovulation.

Saliva: a reliable sample matrix in bioanalytics

Saliva is gaining increasing attention as a bioanalytical sample matrix. Mostly because of the easy and noninvasive collection, it is not only beneficial in endocrinological and behavioral science, but also in pediatrics. Saliva also has the advantage of being the only body fluid which can be collected even during physical exercise, for example, during sportive activities, and there are physiological characteristics that make it superior to serum/plasma or urine for specific scientific questions. This review provides an insight into the physiology of saliva formation, explaining how certain compounds enter this bodily fluid, and gives advice for collection, storage and analytical methods. Finally, it presents a number of reliable and proven applications for saliva analysis from scientific fields including endocrinology, sports medicine, forensics and immunology.

Ultrastructural and physico-chemical characterization of saliva during menstrual cycle in perspective of ovulation in human

Human saliva is a potential diagnostic fluid and any alteration in body might be reflected in saliva so that saliva is considered as "mirror of the body". Variations in salivary hormone level, ultra structure, pH, flow rate, buffering capacity and electrolytes level are found during menstrual cycle in regard to ovulation. Thirty healthy volunteers were used for the assessment of physico-chemical changes in saliva. Reproductive cycle was categorized as pre-ovulation phase (5 to 12 days), ovulation phase (13 or 14 days) and post-ovulation phase (15 to 25 days) according to salivary arborization test and hormonal analysis. Estradiol and luteinizing hormone was gradually increased and attained peak at the level of 2.28 ± 0.20 pg/mL and 1.35 ± 0.41 mIU/mL respectively during the ovulation phase. The electrolytes result clearly indicates that the influx of common electrolytes is important for crystallization and help to induce clear ferning pattern in ovulation phase. Sodium (Na) and chloride (Cl) were found to be high during ovulation phase only. Average salivary pH was 7.5, 7.1, and 7.3 during ovulation, pre- and post-ovulation phases respectively. Buffering capacity of saliva was normal during pre- and post- ovulation phases. In contrast, in ovulation phase the buffer capacity was slightly higher. At the first time, the scanning electron microscopy (SEM) studies revealed the ultra structure difference of saliva during menstrual cycle. During ovulation phase a compact network-shaped mesh was appeared; such structure was not appeared in pre- and post ovulation phases. Additionally, we observed the saliva is arrayed as a fine mosaic-like structure during ovulation. Based on physico-chemical properties and hormonal levels may lead to develop a detection kit/sensor for detecting the ovulation phase in human.

Does salivary protein(s) act an ovulation indicator for women? A hypothesis

Ovulation is an important physiological process in human, and its effect may reflect in body fluids via secretion of biomolecules such as proteins, amino acids, antioxidants, antimicrobial peptides and so on. Recently, the non-invasive sampling approaches are used to diagnose disease status and access health condition of human. Saliva comprises various proteins which are secreted through salivary glands. The proteins present in the saliva may vary in their expression according to the hormonal level and physiological nature of the body which are said to be hormone receptors, stress proteins and antimicrobial peptides. Therefore, it is postulated that saliva can be used in the detection of ovulation time in human using specific protein(s) expression and which can be considered as a best non-invasive method. The identification of these proteins by adopting LC-MS/MS followed by Western blot analysis are possible to identify a promising biomarker for ovulation detection in human.