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(1) Background: In the oral environment, sound enamel and dental restorative materials are immediately covered by a pellicle layer, which enables bacteria to attach. For the development of new materials with repellent surface functions, information on the formation and maturation of salivary pellicles is crucial. Therefore, the present in situ study aimed to investigate the proteomic profile of salivary pellicles formed on different dental composites. (2) Methods: Light-cured composite and bovine enamel samples (controls) were exposed to the oral cavity for 30, 90, and 120 min. All samples were subjected to optical and mechanical profilometry, as well as SEM surface evaluation. Acquired pellicles and unstimulated whole saliva samples were analyzed by SELDI-TOF-MS. The significance was determined by the generalized estimation equation and the post-hoc bonferroni adjustment. (3) Results: SEM revealed the formation of homogeneous pellicles on all test and control surfaces. Profilometry showed that composite surfaces tend to be of higher roughness compared to enamel. SELDI-TOF-MS detected up to 102 different proteins in the saliva samples and up to 46 proteins in the pellicle. Significant differences among 14 pellicle proteins were found between the composite materials and the controls. (4) Conclusions: Pellicle formation was material- and time-dependent. Proteins differed among the composites and to the control.

Purpose: Saliva is an attractive sample source for the biomarker-based testing of several diseases, especially oral cancer. Here, we sought to apply multiplexed LC-MRM-MS to precisely quantify 90 disease-related proteins and assess their intra- and interindividual variability in saliva samples from healthy donors., Experimental Design: We developed two multiplexed LC-MRM-MS assays for 122 surrogate peptides representing a set of disease-related proteins. Saliva samples were collected from 10 healthy volunteers at three different time points (Day 1 morning and afternoon, and Day 2 morning). Each sample was spiked with a constant amount of a 15 N-labeled protein and analyzed by MRM-MS in triplicate. Quantitative results from LC-MRM-MS were calculated by single-point quantification with reference to a known amount of internal standard (heavy peptide)., Results: The CVs for assay reproducibility and technical variation were 13 and 11%, respectively. The average concentrations of the 99 successfully quantified proteins ranged from 0.28 ± 0.58 ng mL -1 for profilin-2 (PFN2) to 8.55 ±8.96 μg mL -1 for calprotectin (S100A8). For the 90 proteins detectable in >50% of samples, the average CVs for intraday, interday, intraindividual, and interindividual samples were 38%, 43%, 45%, and 69%, respectively. The fluctuations of most target proteins in individual subjects were found to be within ± twofold., Conclusions and Clinical Relevance: Our study elucidated the intra- and interindividual variability of 90 disease-related proteins in saliva samples from healthy donors. The findings may facilitate the further development of salivary biomarkers for oral and systemic diseases., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Dermacentor andersoni, known as the Rocky Mountain wood tick, is found in the western United States and transmits pathogens that cause diseases of veterinary and public health importance including Rocky Mountain spotted fever, tularemia, Colorado tick fever and bovine anaplasmosis. Tick saliva is known to modulate both innate and acquired immune responses, enabling ticks to feed for several days without detection. During feeding ticks subvert host defences such as hemostasis and inflammation, which would otherwise result in coagulation, wound repair and rejection of the tick. Molecular characterization of the proteins and pharmacological molecules secreted in tick saliva offers an opportunity to develop tick vaccines as an alternative to the use of acaricides, as well as new anti-inflammatory drugs. We performed proteomics informed by transcriptomics to identify D. andersoni saliva proteins that are secreted during feeding. The transcript data generated a database of 21,797 consensus sequences, which we used to identify 677 proteins secreted in the saliva of D. andersoni ticks fed for 2 and 5days, following proteomic investigations of whole saliva using mass spectrometry. Salivary gland transcript levels of unfed ticks were compared with 2 and 5day fed ticks to identify genes upregulated early during tick feeding. We cross-referenced the proteomic data with the transcriptomic data to identify 157 proteins of interest for immunomodulation and blood feeding. Proteins of unknown function as well as known immunomodulators were identified., (Copyright © 2014 Australian Society for Parasitology Inc. All rights reserved.)

[Display omitted] • Lipidomics identified 23 lipid classes low in glycolipids in tick salivary glands. • Phosphatidylcholine (PC; 26.66%) was the lipid class with the highest representation. • Tick salivary glycolipids were mostly represented by diacylglycerol (DG; 0.48%). • Individuals bitten by ticks produced more phosphatidylcholine-IgG antibodies. • DG levels were higher in tick salivary glands than in tick saliva. Ticks, as hematophagous ectoparasites, can manipulate host immune and metabolic processes, causing tick-borne allergies such as α-Gal syndrome (AGS). Glycolipids with bound galactose-alpha-1–3-galactose (α-Gal) are potential allergenic molecules associated with AGS. Nevertheless, proteins and lipids lacking α-Gal modifications may contribute to tick salivary allergies and be linked to AGS. In this study, we characterized the effect of deglycosylated tick salivary proteins without lipids on treated zebrafish fed with dog food formulated with mammalian (beef, lamb, pork) meat by quantitative proteomics analysis of intestinal samples. The characterization and functional annotations of tick salivary lipids with low representation of glycolipids was conducted using a lipidomics approach. Results showed a significant effect of treatment with saliva and saliva deglycosylated protein fraction on zebrafish abnormal or no feeding (p < 0.005). Treatment with this fraction affected multiple metabolic pathways, defense responses to pathogens and protein metabolism, which correlated with abnormal or no feeding. Lipidomics analysis identified 23 lipid classes with low representation of glycolipids (0.70% of identified lipids). The lipid class with highest representation was phosphatidylcholine (PC; 26.66%) and for glycolipids it corresponded to diacylglycerol (DG; 0.48%). Qualitative analysis of PC antibodies revealed that individuals bitten by ticks were more likely to produce PC-IgG antibodies (p < 0.001). DG levels were significantly higher in tick salivary glands (p < 0.05) compared with tick saliva and salivary fractions. The α-Gal content was higher in tick saliva than in deglycosylated saliva and lipid fractions. These results support a possible role for tick salivary proteins and lipids without α-Gal modifications in AGS. [ABSTRACT FROM AUTHOR]

Introduction: Damage Associated Molecular Patterns (DAMPs) can initiate and amplify immune responses and can play an important role in the sustenance and progression of periodontal diseases. S100A8, S100A9 and their heterodimer, S100A8/9, are DAMPs or alarmins currently being evaluated for their potential as biomarkers in periodontal diseases. Aim: To quantify and compare salivary levels of S100A8, S100A9 and S100A8/9 in periodontal health, gingivitis or stage 1 periodontitis and stages 3 or 4 periodontitis. Materials and Methods: A cross-sectional analytical study was carried out in the Department of Periodontics, Saveetha Dental College and Hospital, Chennai, India, from December 2022 to February 2023. Periodontal examination and saliva sample collection were done for sixty-eight consecutively enrolled subjects who met the inclusion and exclusion criteria. Study subjects were categorised as group 1, which comprised participants with clinical periodontal health (n=20), group 2, subjects with gingivitis or stage 1 periodontitis (n=20), and group 3, which included patients with stages 3 or 4 periodontitis (n=28). Detailed clinical examination and periodontal charting were done in all study subjects. Saliva samples were processed and stored at -80°C, and enzyme-linked immunosorbent assay was done to quantify S100A8, S100A9 and S100A8/9. Data were analysed using International Business Machines (IBM) Statistical Package for the Social Sciences (SPSS) software version 25.0. Salivary levels of S100A8, S100A9 and S100A8/9 were expressed as mean and standard deviation values. Mean values of the three salivary proteins were compared using the non parametric Kruskal-Wallis test. Bonferroni adjusted pairwise comparisons were also done. The p-values less than 0.05 were considered statistically significant. Results: The mean age of study participants was 38.97±7.62 years. Salivary levels of S100A8 were 41.34±14.34, 141.95± 185.25 and 901.37±65.60 pg/mL in groups 1, 2 and 3, respectively. A statistically significant difference was present among the three groups for mean salivary levels of S100A8 (p-value<0.001). Pairwise comparisons showed that salivary S100A8 values in group 3 were significantly higher than the values observed in clinical health (group 1) (p-value<0.001) and those seen in the gingivitis or stage 1 periodontitis group (group 2) (p-value<0.001). Mean salivary levels of S100A9 and S100A8/9 did not show any statistically significant differences between the groups. Conclusion: There is an altered expression of S100A8, S100A9 and S100A8/9 in periodontal diseases compared to clinical health. Salivary levels of S100A8 are markedly different in cases of advanced periodontal destruction than in periodontal health and early stages of periodontal disease. Salivary S100A8 merits potential as a biomarker for periodontal diseases. [ABSTRACT FROM AUTHOR]

Dental caries is a multifactorial chronic disease resulting from the intricate interplay among acid‐generating bacteria, fermentable carbohydrates, and several host factors such as saliva. Saliva comprises several proteins which could be utilized as biomarkers for caries prevention, diagnosis, and prognosis. Mass spectrometry‐based salivary proteomics approaches, owing to their sensitivity, provide the opportunity to investigate and unveil crucial cariogenic pathogen activity and host indicators and may demonstrate clinically relevant biomarkers to improve caries diagnosis and management. The present review outlines the published literature of human clinical proteomics investigations on caries and extensively elucidates frequently reported salivary proteins as biomarkers. This review also discusses important aspects while designing an experimental proteomics workflow. The protein–protein interactions and the clinical relevance of salivary proteins as biomarkers for caries, together with uninvestigated domains of the discipline are also discussed critically. [ABSTRACT FROM AUTHOR]

Simple Summary: Piglets raised at a farm for meat production experience stress that affects their welfare. Recently, it has been demonstrated that several salivary proteins are up- or down-regulated in stressful situations. These could, therefore, be used as biomarkers for stress. This review revisits the definition of stress and defines the protein composition of porcine saliva to finally propose a panel of six salivary stress biomarkers. Identifying the potential presence of stress at the pig farm is fundamental since it affects pig welfare. As a result, a reliable and straightforward tool to monitor stress could record the welfare status of the animals. Although numerous methods to assess the welfare of pigs have been developed in the past, no gold standard has been established yet. Recently, the value of saliva as a tool to identify chronic stress in piglets was explored, as it can be collected fast and non-invasively. Since the protein composition, i.e., the proteome of porcine saliva, responds to stress, the affected proteins could be used as salivary stress biomarkers. The present review first defines stress and its relationship with welfare. Next, the porcine gland-specific salivary proteome is characterized. Finally, six potential salivary biomarkers for stress are proposed, i.e., odorant-binding protein, vomeromodulin-like protein, chitinase, lipocalin-1, long palate lung and nasal epithelium protein, and alpha-2-HS-glycoprotein. [ABSTRACT FROM AUTHOR]

Saliva, an oral secretion primarily originating from salivary glands (SGs), exert critical roles in the ongoing evolutionary interaction between insects and plants. However, identifying insect salivary components poses challenges due to the tiny size of insects, low secretion amounts, and the propensity for degradation after secretion. In this study, we developed a transcriptome-based approach to comprehensively analyze the salivary proteins of the short-headed planthopper, Epeurysa nawaii, a species with unique feeding habits on bamboo. A total of 165 salivary proteins were identified, with 114 secretory genes highly and specifically expressed in SGs. Consistent with most phloem-feeding insects, digestive enzymes, calcium-binding proteins, oxidoreductases, and a few previously reported salivary effectors were ubiquitously distributed in E. nawaii saliva. However, we also identified a substantial portion of salivary proteins exhibiting taxonomy specificity, including 60 E. nawaii-specific and 62 Delphacidae-specific proteins. These taxonomy-restricted proteins potentially play a role in insect adaptation to specific host plants. Our study provides an efficient pipeline for salivary protein identification and serves as a valuable resource for the functional characterization of effectors. [ABSTRACT FROM AUTHOR]

Background: When feeding on a vertebrate host, ticks secrete saliva, which is a complex mixture of proteins, lipids, and other molecules. Tick saliva assists the vector in modulating host hemostasis, immunity, and tissue repair mechanisms. While helping the vector to feed, its saliva modifies the site where pathogens are inoculated and often facilitates the infection process. The objective of this study is to uncover the variation in protein composition of Rhipicephalus microplus saliva during blood feeding. Methods: Ticks were fed on calves, and adult females were collected, weighed, and divided in nine weight groups, representing the slow and rapid feeding phases of blood feeding. Tick saliva was collected, and mass spectrometry analyses were used to identify differentially secreted proteins. Bioinformatic tools were employed to predict the structural and functional features of the salivary proteins. Reciprocal best hit analyses were used to identify conserved families of salivary proteins secreted by other tick species. Results: Changes in the protein secretion profiles of R. microplus adult female saliva during the blood feeding were observed, characterizing the phenomenon known as "sialome switching." This observation validates the idea that the switch in protein expression may serve as a mechanism for evading host responses against tick feeding. Cattle tick saliva is predominantly rich in heme-binding proteins, secreted conserved proteins, lipocalins, and protease inhibitors, many of which are conserved and present in the saliva of other tick species. Additionally, another remarkable observation was the identification of host-derived proteins as a component of tick saliva. Conclusions: Overall, this study brings new insights to understanding the dynamics of the proteomic profile of tick saliva, which is an important component of tick feeding biology. The results presented here, along with the disclosed sequences, contribute to our understanding of tick feeding biology and might aid in the identification of new targets for the development of novel anti-tick methods. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Proteomic profiling of cereal aphid saliva reveals both ubiquitous and adaptive secreted proteins." The correction states that there were errors in Fig 3B of the article, specifically in the lanes for A. pisum, S. avenae, and M. dirhodum. The incorrect panels have been replaced with the correct data from the original experiments. The underlying data supporting the corrected figures are provided in the document. The authors apologize for the errors in the published article. [Extracted from the article]

Sjögren's Disease (SjD) is an autoimmune disorder associated with decreased saliva and/or tear secretions, resulting in patients reporting dryness in the mouth and eyes. Serum autoantibodies directed against the Ro60/SS-A and La/SS-B autoantigens are a distinctive feature of the disease. Analysis of the saliva and tear proteomes represents one promising alternative method of both classifying and monitoring the condition, and research into salivary and tear proteomics in patients with SjD, with and without sicca, has shown its efficacy and practicality in both clinical and research settings. Studies analyzing the saliva proteomics of SjD patients have generally shown an overexpression of proteins involved in T-cell activation, the immune response, β-2 microglobulin, and the recruitment of pro-inflammatory agents. These studies also show a decrease in or downregulation of proteins involved in salivary secretion. Studies analyzing the tear proteomics of patients with SjD have generally indicated an upregulation of proteins involved with TNF-α signaling, B-cell survival, and the recruitment of pro-inflammatory agents. Studies also note the differential expression of tear protein folding as a hallmark of ocular involvement in this condition. These findings help to elucidate the biochemical relationship between the proteomes of saliva/tear fluids and the general pathophysiology of the gland involved with the pathogenesis of this condition, giving further credence to the potential role of salivary and tear proteomics in the future of diagnosis and treatment for patients with SjD. [ABSTRACT FROM AUTHOR]

Cows produce saliva in very large quantities to lubricate and facilitate food processing. Estimates indicate an amount of 50–150 L per day. Human saliva has previously been found to contain numerous antibacterial components, such as lysozyme, histatins, members of the S-100 family and lactoferrin, to limit pathogen colonization. Cows depend on a complex microbial community in their digestive system for food digestion. Our aim here was to analyze how this would influence the content of their saliva. We therefore sampled saliva from five humans and both nose secretions and saliva from six cows and separated the saliva on SDS-PAGE gradient gels and analyzed the major protein bands with LC-MS/MS. The cow saliva was found to be dominated by a few major proteins only, carbonic anhydrase 6, a pH-stabilizing enzyme and the short palate, lung and nasal epithelium carcinoma-associated protein 2A (SPLUNC2A), also named bovine salivary protein 30 kDa (BSP30) or BPIFA2B. This latter protein has been proposed to play a role in local antibacterial response by binding bacterial lipopolysaccharides (LPSs) and inhibiting bacterial growth but may instead, according to more recent data, primarily have surfactant activity. Numerous peptide fragments of mucin-5B were also detected in different regions of the gel in the MS analysis. Interestingly, no major band on gel was detected representing any of the antibacterial proteins, indicating that cows may produce them at very low levels that do not harm the microbial flora of their digestive system. The nose secretions of the cows primarily contained the odorant protein, a protein thought to be involved in enhancing the sense of smell of the olfactory receptors and the possibility of quickly sensing potential poisonous food components. High levels of secretory IgA were also found in one sample of cow mouth drippings, indicating a strong upregulation during an infection. The human saliva was more complex, containing secretory IgA, amylase, carbonic anhydrase 6, lysozyme, histatins and a number of other less abundant proteins, indicating a major difference to the saliva of cows that show very low levels of antibacterial components, most likely to not harm the microbial flora of the rumen. [ABSTRACT FROM AUTHOR]

Ectopic pregnancy (EP) is associated with high maternal morbidity and mortality. Ultrasonography is the only dependable diagnostic tool for confirming an ectopic pregnancy. In view of inadequate early detection methods, women suffer from a high-life risk due to the severity of EP. Early detection of EP using pathological/molecular markers will possibly improve clinical diagnosis and patient management. Salivary proteins contain potential biomarkers for diagnosing and detecting various physiological and/or pathological conditions. Therefore, the present investigation was designed to explore the salivary proteome with special reference to EP. Gel-based protein separation was performed on saliva, followed by identification of proteins using Liquid Chromatography-Tandem Mass Spectrometry (LC–MS/MS). Totally, 326 proteins were identified in the salivary samples, among which 101 were found to be specific for ruptured ectopic pregnancy (EPR). Reactome analysis revealed innate immune system, neutrophil degranulation, cell surface interactions at the vascular wall, and FCERI-mediated NF-kB activation as the major pathways to which the salivary proteins identified during EPR are associated. Glutathione-S-transferase omega-1 (GSTO1) is specific for EPR and has been reported as a candidate biomarker in the serum of EPR patients. Therefore, saliva would be a potential source of diagnostic non-invasive protein biomarker(s) for EP. Intensive investigation on the salivary proteins specific to EP can potentially lead to setting up of a panel of candidate biomarkers and developing a non-invasive protein-based diagnostic kit. [ABSTRACT FROM AUTHOR]

Early detection is crucial for the treatment and prognosis of oral cancer, a potentially lethal condition. Tumor markers are abnormal biological byproducts produced by malignant cells that may be found and analyzed in a variety of bodily fluids, including saliva. Early detection and appropriate treatment can increase cure rates to 80–90% and considerably improve quality of life by reducing the need for costly, incapacitating medicines. Salivary diagnostics has drawn the interest of many researchers and has been proven to be an effective tool for both medication monitoring and the diagnosis of several systemic diseases. Since researchers are now searching for biomarkers in saliva, an accessible bodily fluid, for noninvasive diagnosis of oral cancer, measuring tumor markers in saliva is an interesting alternative to blood testing for early identification, post-treatment monitoring, and monitoring high-risk lesions. New molecular markers for oral cancer detection, treatment, and prognosis have been found as a result of developments in the fields of molecular biology and salivary proteomics. The numerous salivary tumor biomarkers and how they relate to oral cancer and pre-cancer are covered in this article. We are optimistic that salivary protein biomarkers may one day be discovered for the clinical detection of oral cancer because of the rapid advancement of proteomic technology. [ABSTRACT FROM AUTHOR]

This study aimed to compare the proteomic profile of stimulated and unstimulated saliva samples from pregnant women with/without obesity and periodontitis. Pregnant women were allocated into four groups: with obesity and periodontitis (OP); with obesity but without periodontitis (OWP); with normal BMI but with periodontitis (NP); with normal BMI and without periodontitis (NWP). Stimulated saliva (SS) and unstimulated saliva (US) samples were collected, and salivary proteins were extracted and individually processed by proteomic analysis (nLC-ESI-MS/MS). Proteins involved with the immune response process, antioxidant activity, and retina homeostasis were decreased or absent in SS samples from all groups (i.e., Antileukoproteinase, Lysozyme C, Alpha-2-macroglobulin-like protein 1, Heat shock proteins—70 kDa 1-like, 1A, 1B, 6, Heat shock-related 70 kDa protein 2, Putative Heat shock 70 kDa protein 7, Heat shock cognate 71 kDa). Additionally, proteins related to the carbohydrate metabolic process and glycolytic and glucose metabolic process were absent in SS, mainly from OP and OWP (i.e., Frutose-bisphosphate aldose A, Glusoce-6-phosphate isomerase, Pyruvate kinase). Saliva stimulation decreased important proteins involved with immune response and inflammation process in all groups. Unstimulated salivary samples seem to be the best choice for the proteomic approach in pregnant women. [ABSTRACT FROM AUTHOR]

Borrelia burgdorferi sensu lato , the causative agents of Lyme borreliosis, are transmitted by Ixodes ticks. Tick saliva proteins are instrumental for survival of both the vector and spirochete and have been investigated as targets for vaccine targeting the vector. In Europe, the main vector for Lyme borreliosis is Ixodes ricinus , which predominantly transmits Borrelia afzelii. We here investigated the differential production of I. ricinus tick saliva proteins in response to feeding and B. afzelii infection. Label-free Quantitative Proteomics and Progenesis QI software was used to identify, compare, and select tick salivary gland proteins differentially produced during tick feeding and in response to B. afzelii infection. Tick saliva proteins were selected for validation, recombinantly expressed and used in both mouse and guinea pig vaccination and tick-challenge studies. We identified 870 I. ricinus proteins from which 68 were overrepresented upon 24-hours of feeding and B. afzelii infection. Selected tick proteins were successfully validated by confirming their expression at the RNA and native protein level in independent tick pools. When used in a recombinant vaccine formulation, these tick proteins significantly reduced the post-engorgement weights of I. ricinus nymphs in two experimental animal models. Despite the reduced ability of ticks to feed on vaccinated animals, we observed efficient transmission of B. afzelii to the murine host. Using quantitative proteomics, we identified differential protein production in I. ricinus salivary glands in response to B. afzelii infection and different feeding conditions. These results provide novel insights into the process of I. ricinus feeding and B. afzelii transmission and revealed novel candidates for an anti-tick vaccine. [ABSTRACT FROM AUTHOR]

Background: Aspiration pneumonia (AP), which is a major cause of death in the elderly, does present with typical symptoms in the early stages of onset, thus it is difficult to detect and treat at an early stage. In this study, we identified biomarkers that are useful for the detection of AP and focused on salivary proteins, which may be collected non-invasively. Because expectorating saliva is often difficult for elderly people, we collected salivary proteins from the buccal mucosa. Methods: We collected samples from the buccal mucosa of six patients with AP and six control patients (no AP) in an acute-care hospital. Following protein precipitation using trichloroacetic acid and washing with acetone, the samples were analyzed by liquid chromatography and tandem mass spectrometry (LC–MS/MS). We also determined the levels of cytokines and chemokines in non-precipitated samples from buccal mucosa. Results: Comparative quantitative analysis of LC–MS/MS spectra revealed 55 highly (P values < 0.10) abundant proteins with high FDR confidence (q values < 0.01) and high coverage (> 50%) in the AP group compared with the control group. Among the 55 proteins, the protein abundances of four proteins (protein S100-A7A, eukaryotic translation initiation factor 1, Serpin B4, and peptidoglycan recognition protein 1) in the AP group showed a negative correlation with the time post-onset; these proteins are promising AP biomarker candidates. In addition, the abundance of C-reactive protein (CRP) in oral samples was highly correlated with serum CRP levels, suggesting that oral CRP levels may be used as a surrogate to predict serum CRP in AP patients. A multiplex cytokine/chemokine assay revealed that MCP-1 tended to be low, indicating unresponsiveness of MCP-1 and its downstream immune pathways in AP. Conclusion: Our findings suggest that oral salivary proteins, which are obtained non-invasively, can be utilized for the detection of AP. [ABSTRACT FROM AUTHOR]

Background: Pharyngocutaneous fistula (PCF) and salivary leaks are well known complications of head and neck surgery. The medical management of PCF has included the use of octreotide without a well‐defined understanding of its therapeutic mechanism. We hypothesized that octreotide induces alterations in the saliva proteome and that these alterations may provide insight into the mechanism of action underlying improved PCF healing. We undertook an exploratory pilot study in healthy controls that involved collecting saliva before and after a subcutaneous injection of octreotide and performing proteomic analysis to determine the effects of octreotide. Methods: Four healthy adult participants provided saliva samples before and after subcutaneous injection of octreotide. A mass‐spectrometry based workflow optimized for the quantitative proteomic analysis of biofluids was then employed to analyze changes in salivary protein abundance after octreotide administration. Results: There were 3076 human, 332 Streptococcus mitis, 102 G. haemolyans, and 42 Granulicatella adiacens protein groups quantified in saliva samples. A paired statistical analysis was performed using the generalized linear model (glm) function in edgeR. There were and ~300 proteins that had a p <.05 between the pre‐ and post‐octreotide groups ~50 proteins with an FDR‐corrected p <.05 between pre‐ and post‐groups. These results were visualized using a volcano plot after filtering on proteins quantified by 2 more or unique precursors. Both human and bacterial proteins were among the proteins altered by octreotide treatment. Notably, four isoforms of the human cystatins, belonging to a family of cysteine proteases, that had significantly lower abundance after treatment. Conclusion: This pilot study demonstrated octreotide‐induced downregulation of cystatins. By downregulation of cystatins in the saliva, there is decreased inhibition of cysteine proteases such as Cathepsin S. This results in increased cysteine protease activity that has been linked to enhanced angiogenic response, cell proliferation and migration that have resulted in improved wound healing. These insights provide first steps at furthering our understanding of octreotide's effects on saliva and reports of improved PCF healing. [ABSTRACT FROM AUTHOR]

The metabolomics and proteomics analysis of saliva, an excellent biofluid that is a rich source of biological compounds, allows for the safe and frequent screening of drugs, their metabolites, and molecular biomarkers of various diseases. One of the most frequently used analytical methods in saliva analysis is liquid chromatography coupled with mass spectrometry (LC-MS) and tandem mass spectrometry. The low ionisation efficiency of some compounds and a complex matrix makes their identification by MS difficult. Furthermore, quantitative analysis by LC-MS frequently cannot be performed without isotopically labelled standards, which usually have to be specially synthesised. This review presented reports on qualitative and quantitative approaches in salivary metabolomics and proteomics. The purpose of this manuscript was to present the challenges, advances, and future prospects of mass spectrometry, both in the analysis of salivary metabolites and proteins. The presented review should appeal to those interested in the recent advances and trends in qualitative and quantitative mass spectrometry in salivary metabolomics and proteomics, which may facilitate a diagnostic accuracy, the evaluation of treatment efficacy, the early diagnosis of disease, and a forensic investigation of some unapproved drugs for any medical or dietary administration. [ABSTRACT FROM AUTHOR]

Introduction: Salivary glands and their secreted proteins play an important role in the feeding process of sap-sucking aphids. The determination of saliva composition is an important step in understanding host plant adaptation of aphids. Pseudoregma bambucicola is a severe bamboo pest in subtropical areas and the only aphid species that can exclusively feed on hard stalks of bamboos. How this species can penetrate and degrade hard bamboo cell walls and utilize a very specialized niche are important unanswered questions. Methods: In this study, comprehensive analyses based on transcriptome sequencing, RT-qPCR, liquid chromatography-tandem spectrometry (LC-MS/MS) and bioinformatics were conducted on dissected salivary glands and secreted saliva of P. bambucicola to characterize the overall gene expression and salivary protein composition, and to identify putative effector proteins important for aphid-plant interactions. Results and Discussion: Some secretory proteins homologous to known aphid effectors important for aphid-plant interactions, such as digestive enzymes, detoxifying and antioxidant enzymes and some effectors modulating plant defenses, are also detected in salivary gland transcriptome and salivary gland and/or saliva secretomes in P. bambucicola. This indicates that these effectors are probably be essential for enabling P. bambucicola feeding on bamboo host. Although several plant cell wall degrading enzymes (PCWDEs) can be identified from transcriptome, most of the enzymes identified in salivary glands showed low expression levels and they only represent a small fraction of the complete set of enzymes for degrading cellulose and hemicellulose. In addition, our data show that P. bambucicola has no its own ability to produce pectinases. Overall, our analyses indicate that P. bambucicola may lose its own ability to express and secrete key PCWDEs, and its adaptation to unique feeding habit may depend on its symbiotic bacteria. [ABSTRACT FROM AUTHOR]

Salivary proteins in the oral secretion (OS) of chewing insects play a crucial role in insect-plant interactions during feeding. The rice leaf folder Cnaphalocrocis medinalis , a notorious pest in global rice production, triggers defense responses during feeding, but little is known about its salivary proteins. In this study, we confirmed that C. medinalis releases OS during feeding. By employing transcriptomic analysis and liquid chromatography-tandem mass spectroscopy (LC-MS/MS), we examined the salivary proteins from labial salivary glands and OS from C. medinalis. A total of 14,397 genes were expressed at the RNA level and 229 salivary proteins were identified. Comparative analysis with other 25 arthropod species revealed that 43 proteins were unique to C. medinalis. Expression pattern analysis revealed that most of the selected genes were highly expressed in the gut and the larval stages (4th–5th instar). These findings provide a comprehensive resource for future functional studies of salivary proteins, offering new insights into the molecular mechanisms by which C. medinalis modulates plant defenses and potential applications in pest management. [Display omitted] • The rice leaf folder Cnaphalocrocis medinalis release oral secretions when feeding on plants. • 229 salivary proteins were identified from C. medinalis oral secretions. • Salivary proteins from C. medinalis may be involved in digestion, immunity, detoxification, herbivore offense, etc. [ABSTRACT FROM AUTHOR]

• Saliva is an attractive matrix for SARS-CoV-2 new biomarkers identification. • COVID-19 symptoms are associated to differential proteins expression in saliva. • IL1RA, CYST-SA, S100A8-A9, CA6, FABP5 separate symptomatic from asymptomatic forms. SARS-CoV-2 infection spawns from an asymptomatic condition to a fatal disease. Age, comorbidities, and several blood biomarkers are associated with infection outcome. We searched for biomarkers by untargeted and targeted proteomic analysis of saliva, a source of viral particles and host proteins. Saliva samples from 19 asymptomatic and 16 symptomatic SARS-CoV-2 infected subjects, and 20 controls were analyzed by LC-MS/MS for untargeted peptidomic (flow through of 10 kDa filter) and proteomic (trypsin digestion of filter retained proteins) profiling. Peptides from 53 salivary proteins were identified. ADF was detected only in controls, while IL1RA only in infected subjects. PRPs, DSC2, FABP5, his-1, IL1RA, PRH1, STATH, SMR3B, ANXA1, MUC7, ACTN4, IGKV1-33 and TGM3 were significantly different between asymptomatic and symptomatic subjects. Retained proteins were 117, being 11 highly different between asymptomatic and symptomatic (fold change ≥2 or ≤−2). After validation by LC-MS/MS-SRM (selected reaction monitoring analysis), the most significant discriminant proteins at PCA were IL1RA, CYSTB, S100A8, S100A9, CA6, and FABP5. The differentially abundant proteins involved in innate immunity (S100 proteins), taste (CA6 and cystatins), and viral binding to the host (FABP5), appear to be of interest for use as potential biomarkers and drugs targets. [ABSTRACT FROM AUTHOR]

Summary: Aphids secrete diverse repertoires of salivary effectors into host plant cells to promote infestation by modulating plant defence. The greenbug Schizaphis graminum is an important cereal aphid worldwide. However, the secreted effectors of S. graminum are still uncharacterized. Here, 76 salivary proteins were identified from the watery saliva of S. graminum using transcriptome and proteome analyses. Among them, a putative salivary effector Sg2204 was significantly up‐regulated during aphid feeding stages, and transient overexpression of Sg2204 in Nicotiana benthamiana inhibited cell death induced by BAX or INF1. Delivering Sg2204 into wheat via the type III secretion system of Pseudomonas fluorescens EtAnH suppressed pattern‐triggered immunity (PTI)‐associated callose deposition. The transcript levels of jasmonic acid (JA)‐ and salicylic acid (SA)‐associated defence genes of wheat were significantly down‐regulated, and the contents of both JA and SA were also significantly decreased after delivery of Sg2204 into wheat leaves. Additionally, feeding on wheat expressing Sg2204 significantly increased the weight and fecundity of S. graminum and promoted aphid phloem feeding. Sg2204 was efficiently silenced via spray‐based application of the nanocarrier‐mediated transdermal dsRNA delivery system. Moreover, Sg2204‐silenced aphids induced a stronger wheat defence response and resulted in negative impacts on aphid feeding behaviour, survival and fecundity. Silencing of Sg2204 homologues from four aphid species using nanocarrier‐delivered dsRNA also significantly reduced aphid performance on host plants. Thus, our study characterized the salivary effector Sg2204 of S. graminum involved in promoting host susceptibility by suppressing wheat defence, which can also be regarded as a promising RNAi target for aphid control. [ABSTRACT FROM AUTHOR]

Simple Summary: One of the most crucial topics about cattle breeding is pregnancy. During this state, there are many changes in protein expression and abundance. These changes find reflection not only in plasma protein patterns but also in saliva, which is easier to obtain than blood. The aim of this study was the analysis of plasma and salivary protein profiles in pregnant cows in order to search for valuable markers of pregnancy status. In this study, the presence of apolipoproteins possibly related to bovine pregnancy was confirmed both in plasma and saliva. This means that saliva can be considered a good source of information about the condition of the organism, including during pregnancy. It is possible that the comparison of salivary and plasma proteomes can be a helpful tool to assess the pregnancy status of cattle, and can be useful for developing rapid tests from saliva. Pregnancy is a physiological state that can be described, from a biochemical point of view, using protein patterns. The present study focused on the comparison of protein patterns between the saliva and plasma of pregnant cows to search for possible markers which are present both in plasma and saliva. Saliva and plasma were collected from healthy, pregnant (3–4 months) and non-pregnant (C; n = 4) cows aged between 4 and 8 years (P; n = 8) from the same farm. Biological material was analyzed using 2D electrophoresis and MS identification. Among identified spots, there were those which could be related to pregnancy (e.g., apolipoproteins I and II in all examined matrices or transforming growth factor-beta-induced protein ig-h3 in albumin-free plasma) as well as those which are responsible for regulating of cellular processes (e.g., pyruvate kinase and aspartate aminotransferase in all examined matrices, or lactate dehydrogenase, phosphoglycerate kinase, and NADH dehydrogenase in plasma). Further identification of common spots and those only specific to saliva as well as the comparison between other periods of pregnancy are necessary; it is already clear that saliva can be considered a valuable diagnostic matrix containing potential markers of physiological and pathological status. [ABSTRACT FROM AUTHOR]

COVID-19 is the most impacting global pandemic of all time, with over 600 million infected and 6.5 million deaths worldwide, in addition to an unprecedented economic impact. Despite the many advances in scientific knowledge about the disease, much remains to be clarified about the molecular alterations induced by SARS-CoV-2 infection. In this work, we present a hybrid proteomics and in silico interactomics strategy to establish a COVID-19 salivary protein profile. Data are available via ProteomeXchange with identifier PXD036571. The differential proteome was narrowed down by the Partial Least-Squares Discriminant Analysis and enrichment analysis was performed with FunRich. In parallel, OralInt was used to determine interspecies Protein-Protein Interactions between humans and SARS-CoV-2. Five dysregulated biological processes were identified in the COVID-19 proteome profile: Apoptosis, Energy Pathways, Immune Response, Protein Metabolism and Transport. We identified 10 proteins (KLK 11, IMPA2, ANXA7, PLP2, IGLV2-11, IGHV3-43D, IGKV2-24, TMEM165, VSIG10 and PHB2) that had never been associated with SARS-CoV-2 infection, representing new evidence of the impact of COVID-19. Interactomics analysis showed viral influence on the host immune response, mainly through interaction with the degranulation of neutrophils. The virus alters the host's energy metabolism and interferes with apoptosis mechanisms. [ABSTRACT FROM AUTHOR]

The practice of exercise can change biological markers. Thus, the use of saliva to define possible biomarkers has increased with the advances in "omics" techniques. Therefore, this study analyzed the salivary proteomic profile in young adults before and after interval exercise. Five adults, without comorbidities and with normal salivary flow, aged between 20 and 35 years (3 men and 2 women) were selected. The collection of stimulated (SS) and non-stimulated (NSS) saliva was done before (BE) and after (AE) exercise, which consisted of interval exercise with 5 min walking on a treadmill and 5 min at rest, during a total of 40 min. The proteins were extracted individually and processed by label-free proteomics. There was no significant difference between BE and AE salivary flows. For SS, 69 and 60 proteins were found BE (12 exclusives) and AE (3 exclusives), respectively. Ten subunits of immunoglobulins (8 more than twofold), as well as Lysozyme C and Cystatin-S, were increased AE compared to BE. Six hemoglobin's isoforms were decreased AE compared to BE. For NSS, 76 and 65 proteins were found BE (18 exclusives) and AE (7 exclusives), respectively. Albumin was increased AE, while Basic salivary proline-rich protein 1 and 2 decreased. Apolipoprotein A-I was identified exclusively AE compared to BE. The salivary proteome after interval exercise suggests increase of immunity. [ABSTRACT FROM AUTHOR]

Simple Summary: The conception rate of sows is an important factor affecting the efficiency and income of pig farms. At present, the traditional estrus identification methods used in production, such as the external observation method and back pressure reaction method, have the disadvantages of being time-consuming and laborious, with low accuracy and high requirements for technicians. In addition, the abnormal estrus status of sows, such as continuous estrus and short estrus, will also lead to misjudgment during estrus inspection, which will affect the conception rate of sows and reduce production efficiency. Therefore, the purpose of this study was to explore a new method for estrus identification, to provide an important reference for accurate estrus identification of sows by screening salivary proteins related to estrus, and to provide a reference for the development of kits/strips for estrus identification of sows. 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. [ABSTRACT FROM AUTHOR]

Sepsis is a systemic inflammatory response triggered by an infectious agent and is recognized by the World Health Organization as a global concern, since it is one of the major causes of severe illness in humans and animals. The study of the changes that can occur in saliva and serum in sepsis can contribute to a better understanding of the pathophysiological mechanisms involved in the process and also to discover potential biomarkers that can help in its diagnosis and monitoring. The objective of this study was to characterize the changes that occur in the salivary and serum proteome of pigs with experimentally-induced sepsis. The study included five pigs with sepsis induced by LPS administration and five pigs with non-septic inflammation induced by turpentine for comparative purposes. In saliva, there were eighteen salivary proteins differentially expressed in the sepsis condition and nine in non-septic inflammation. Among these, significant increments in aldolase A and serpin B12 only occurred in the sepsis model. Changes in aldolase A were validated in a larger population of pigs with sepsis due to Streptococcus suis infection. In serum, there were 30 proteins differentially expressed in sepsis group and 26 proteins in the non-septic group, and most of the proteins that changed in both groups were related to non-specific inflammation. In the saliva of the septic animals there were some specific pathways activated, such as the organonitrogen compound metabolic process and lipid transport, whereas, in the serum, one of the main activated pathways was the regulation of protein secretion. Overall, saliva and serum showed different proteome variations in response to septic inflammation and could provide complementary information about the pathophysiological mechanisms occurring in this condition. Additionally, salivary aldolase A could be a potential biomarker of sepsis in pigs that should be confirmed in a larger population. [ABSTRACT FROM AUTHOR]

Psychological stress is associated with various oral diseases such as aphthous stomatitis, oral lichen planus, taste disturbances and glossodynia. However, the underlying mechanism is still unknown. The aim of this study was to determine the effect of psychological stress on salivary proteins and the oral microbiota in a rat model of chronic restraint stress. Six-week-old Sprague Dawley rats were subjected to restraint stress for four hours daily for 1 month. The behavior, weights of the adrenal glands, and serum corticosterone levels were evaluated as stress markers. Proteomic analysis of the saliva was performed using two-dimensional gel electrophoresis followed by mass spectrometry and Western blotting. Analysis of the oral microbiota was performed via 16S rRNA next-generation sequencing. The low mean body weights, lower number of entries and time spent in the open arm of elevated plus maze, high adrenal gland/body weight ratios, and high serum corticosterone levels confirmed the high levels of stress in the stress group of rats compared to the controls. Thirty-three protein spots were found to be significantly altered between the two groups. After silver staining, seven visible spots were subjected for mass spectrometry, and the expression levels of the two most significantly altered proteins, BPI fold containing family A member 2 and von Ebner's gland protein, were confirmed by Western blotting. 16S rRNA sequencing analysis revealed a significant reduction in alpha diversity in the stress group compared to the controls. The abundances of oral bacteria, such as Facklamia and Corynebacterium, were significantly altered between the two groups. Additionally, analysis with PICRUSt2 software predicted 37 different functional pathways to be altered between the groups. In conclusion, the present study identified altered salivary proteins and oral microbiota due to psychological stress. These findings might aid in understanding the pathogenesis of stress-related oral diseases. [ABSTRACT FROM AUTHOR]

Simple Summary: Equine gastric ulcer syndrome (EGUS) is a highly prevalent disease with a major clinical importance due to its negative effects on the welfare and performance of horses. EGUS can be distinguished into two different diseases depending on which anatomical region is affected: equine glandular gastric disease (EGGD), in which there is a lesion in the glandular stomach, and equine squamous gastric disease (ESGD), in which the alteration appears in the non-glandular stomach. EGUS has nonspecific clinical signs, and its underlying mechanism has not been completely elicited. Therefore, it would be of interest to clarify the pathophysiology and identify potential biomarkers of this syndrome. This study detected differences in the salivary and serum proteome between horses with EGUS and healthy horses, and also between horses with EGGD and ESGD. The most upregulated proteins in EGGD were related to the immune activation whereas, in horses with ESGD, the proteins with the most significant changes were associated with the squamous cell regulation and growth. Compared to serum, saliva had a higher number of proteins showing significant changes and also showed a different pattern of changes, indicating that the proteins in both fluids show a different response to the disease and can provide complementary information. Changes in the salivary proteome in 12 horses with the two diseases included in equine gastric ulcer syndrome (EGUS), equine glandular gastric disease (EGGD) (n = 6) and equine squamous gastric disease (ESGD) (n = 6), were evaluated using a high-resolution LC-MS/MS analysis of TMT-labelled peptides and compared to 10 healthy control horses. Serum was also analysed for comparative purposes. The comparison between the horses with EGGD and controls showed significant changes in 10 salivary proteins, whereas 36 salivary proteins were differently abundant between ESGD and control groups. The most upregulated proteins in the case of EGGD were related to immune activation whereas, in horses with ESGD, the most significantly changed proteins were associated with squamous cell regulation and growth. Compared to serum, saliva showed a higher number of proteins with significant changes and a different pattern of changes. The proteins identified in our study, in addition to providing new information about the pathophysiological mechanisms in these diseases, could have the potential to be novel biomarkers for the diagnosis or monitoring of EGGD and ESGD. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine if there is an association between the salivary protein profile and disease control in asthma. Thirty asthmatic patients (17 adults and 13 children) participated in this study. Saliva samples were collected from healthy subjects, controlled and uncontrolled asthmatics. Individual samples from each group were combined to form a pooled sample, from which proteomic analysis was performed using gel-based quantitative proteomics. Fourteen out of thirty asthmatics were classified to be controlled asthma. Most of asthmatics received inhaled corticosteroids as the controller medications. SDS-PAGE showed predominant bands at high molecular weight in asthmatic saliva compared to that of the controls. Shotgun proteomic analyses indicated that 193 salivary proteins were expressed in both controlled and uncontrolled asthmatics. They were predicted to associate with proteins involved in pathogenesis of asthma including IL-5, IL-6, MCP-1, VEGF, and periostin and asthma medicines (Cromolyn, Nedocromil, and Theophylline). Nucleoside diphosphate kinase (NME1-NME2) only expressed in controlled asthmatics whereas polycystic kidney and hepatic disease 1 (PKHD1)/fibrocystin, zinc finger protein 263 (ZNF263), uncharacterized LOC101060047 (ENSG00000268865), desmoglein 2 (DSG2) and S100 calcium binding protein A2 (S100A2) were only found in uncontrolled asthma. Therefore, the six proteins were associated with disease control in children and adults with asthma. Our findings suggest that NME1-NME2, PKHD1, ZNF 263, uncharacterized LOC101060047, DSG 2 and S100 A2 in saliva are associated with disease control in asthma. [ABSTRACT FROM AUTHOR]

Background: The argasid tick Ornithodoros erraticus is the main vector of tick-borne human relapsing fever (TBRF) and African swine fever (ASF) in the Mediterranean Basin. The prevention and control of these diseases would greatly benefit from the elimination of O. erraticus populations, and anti-tick vaccines are envisaged as an effective and sustainable alternative to chemical acaricide usage for tick control. Ornithodoros erraticus saliva contains bioactive proteins that play essential functions in tick feeding and host defence modulation, which may contribute to host infection by tick-borne pathogens. Hence, these proteins could be candidate antigen targets for the development of vaccines aimed at the control and prevention of O. erraticus infestations and the diseases this tick transmits. The objective of the present work was to obtain and characterise the proteome of the saliva of O. erraticus adult ticks as a means to identify and select novel salivary antigen targets. Methods: A proteomics informed by transcriptomics (PIT) approach was applied to analyse samples of female and male saliva separately using the previously obtained O. erraticus sialotranscriptome as a reference database and two different mass spectrometry techniques, namely liquid chromatography–tandem mass spectrometry (LC–MS/MS) in data-dependent acquisition mode and sequential window acquisition of all theoretical fragment ion spectra MS (SWATH-MS). Results: Up to 264 and 263 proteins were identified by LC–MS/MS in the saliva of O. erraticus female and male ticks, respectively, totalling 387 non-redundant proteins. Of these, 224 were further quantified by SWATH-MS in the saliva of both male and female ticks. Quantified proteins were classified into 23 functional categories and their abundance compared between sexes. Heme/iron-binding proteins, protease inhibitors, proteases, lipocalins and immune-related proteins were the categories most abundantly expressed in females, while glycolytic enzymes, protease inhibitors and lipocalins were the most abundantly expressed in males. Ninety-seven proteins were differentially expressed between the sexes, of which 37 and 60 were overexpressed in females and males, respectively. Conclusions: The PIT approach demonstrated its usefulness for proteomics studies of O. erraticus, a non-model organism without genomic sequences available, allowing the publication of the first comprehensive proteome of the saliva of O. erraticus reported to date. These findings confirm important quantitative differences between sexes in the O. erraticus saliva proteome, unveil novel salivary proteins and functions at the tick–host feeding interface and improve our understanding of the physiology of feeding in O. erraticus ticks. The integration of O. erraticus sialoproteomic and sialotranscriptomic data will drive a more rational selection of salivary candidates as antigen targets for the development of vaccines aimed at the control of O. erraticus infestations and the diseases it transmits. [ABSTRACT FROM AUTHOR]

Objectives: Salivary glands are affected during radiotherapy in the head and neck region, leading to a reduction in salivary flow and changes its composition. Besides negatively affecting the oral soft tissues, this can also lead to dental impairment. Thus, we evaluated the effect of radiotherapy in the proteomic profile of the saliva in patients with head and neck cancer (HNC). Materials and methods: HNC patients had their saliva collected before (BRT), during (2–5 weeks; DRT), and after (3–4 months; ART) radiotherapy. Saliva was also collected from healthy volunteers (control; C). Samples were processed for proteomic analysis. Results: In total, 1055 proteins were identified, among which 46 were common to all groups, while 86, 86, 286, and 395 were exclusively found in C, BRT, DRT, and ART, respectively. Remarkably, alpha-enolase was increased 35-fold DRT compared with BRT, while proline-rich proteins were decreased. ART there was a 16-fold increase in scaffold attachment factor-B1 and a 3-fold decrease in alpha-enolase and several cystatins. When compared with C, salivary proteins of BRT patients showed increases cystatin-C, lysozyme C, histatin-1, and proline-rich proteins Conclusion/clinical revelance: Both HNC and radiotherapy remarkably change the salivary protein composition. Altogether, our results, for the first time, suggest investigating alpha-enolase levels in saliva DRT in future studies as a possible biomarker and strategy to predict the efficiency of the treatment. Moreover, our data provide important insights for designing dental products that are more effective for these patients and contribute to a better understanding of the progressive changes in salivary proteins induced by radiotherapy. [ABSTRACT FROM AUTHOR]

Arboviruses such as dengue (DENV), Zika (ZIKV) and chikungunya (CHIKV) viruses infect close to half a billion people per year, and are primarily transmitted through Aedes aegypti bites. Infection-induced changes in mosquito salivary glands (SG) influence transmission by inducing antiviral immunity, which restricts virus replication in the vector, and by altering saliva composition, which influences skin infection. Here, we profiled SG proteome responses to DENV serotype 2 (DENV2), ZIKV and CHIKV infections by using high-resolution isobaric-tagged quantitative proteomics. We identified 218 proteins with putative functions in immunity, blood-feeding or related to the cellular machinery. We observed that 58, 27 and 29 proteins were regulated by DENV2, ZIKV and CHIKV infections, respectively. While the regulation patterns were mostly virus-specific, we separately depleted four uncharacterized proteins that were upregulated by all three viral infections to determine their effects on these viral infections. Our study suggests that gamma-interferon responsive lysosomal thiol-like (GILT-like) has an anti-ZIKV effect, adenosine deaminase (ADA) has an anti-CHIKV effect, salivary gland surface protein 1 (SGS1) has a pro-ZIKV effect and salivary gland broad-spectrum antiviral protein (SGBAP) has an antiviral effect against all three viruses. The comprehensive description of SG responses to three global pathogenic viruses and the identification of new restriction factors improves our understanding of the molecular mechanisms influencing transmission. [ABSTRACT FROM AUTHOR]

Salivary mucin MUC5B seems to promote biodiversity in dental biofilms, and thereby oral health, for example, by inducing synergistic 'mucolytic' activities in a variety of microbial species that need to cooperate for the release of nutrients from the complex glycoprotein. Knowledge of how early colonizers interact with host salivary proteins is integral to better understand the maturation of putatively harmful oral biofilms and could provide key insights into biofilm physiology. The early oral colonizer Streptococcus gordonii DL1 was grown planktonically and in biofilm flow cell systems with uncoated, MUC5B or low-density salivary protein (LDP) coated surfaces. Bacterial cell proteins were extracted and analyzed using a quantitative mass spectrometry-based workflow, and differentially expressed proteins were identified. Overall, the proteomic profiles of S. gordonii DL1 were similar across conditions. Six novel biofilm cell proteins and three planktonic proteins absent in all biofilm cultures were identified. These differences may provide insights into mechanisms for adaptation to biofilm growth in this species. Salivary MUC5B also elicited specific responses in the biofilm cell proteome. These regulations may represent mechanisms by which this mucin could promote colonization of the commensal S. gordonii in oral biofilms. [ABSTRACT FROM AUTHOR]

The whitefly Bemisia tabaci is a notorious agricultural pest of many crops worldwide. Although it is thought that B. tabaci secretes saliva into the host plant to counter plant defenses, knowledge on the whitefly salivary proteome is limited. Here, we characterized the gene/protein repertoires of B. tabaci salivary glands and secreted saliva by transcriptomic and liquid chromatography tandem mass spectroscopy analyses. A total of 698 salivary gland‐enriched unigenes and 171 salivary proteins were identified. Comparative analysis between the B. tabaci salivary proteins and those of different arthropod species revealed numerous similarities in proteins associated with binding, hydrolysis, and oxidation‐reduction, which demonstrates a degree of conservation across herbivorous saliva. There were 74 proteins only identified in B. tabaci saliva, of which 34 were B. tabaci‐specific. In addition, 13 salivary proteins, of which 11 were B. tabaci‐specific, were differentially regulated when B. tabaci fed on different hosts. Our results provide a good resource for future functional studies of whitefly salivary effectors, and might be useful in pest management. [ABSTRACT FROM AUTHOR]

Plant Growth-Promoting Rhizobacteria (PGPR) induce systemic resistance (SR) in plants, decreasing the development of phytopathogens. The FZB42 strain of Bacillus velezensis is known to induce an SR against pathogens in various plant species. Previous studies suggested that it could also influence the interactions between plants and associated pests. However, insects have developed several strategies to counteract plant defenses, including salivary proteins that allow the insect escaping detection, manipulating defensive pathways to its advantage, deactivating early signaling processes, or detoxifying secondary metabolites. Because Brown Marmorated Stink Bug (BMSB) Halyomorpha halys is highly invasive and polyphagous, we hypothesized that it could detect the PGPR-induced systemic defenses in the plant, and efficiently adapt its salivary compounds to counteract them. Therefore, we inoculated a beneficial rhizobacterium on Vicia faba roots and soil, previous to plant infestation with BMSB. Salivary gland proteome of BMSB was analyzed by LC–MS/MS and a label-free quantitative proteomic method. Among the differentially expressed proteins, most were up-regulated in salivary glands of insects exposed to PGPR-treated plants for 24 h. We could confirm that BMSB was confronted with a stress during feeding on PGPR-treated plants. The to-be-confirmed defensive state of the plant would have been rapidly detected by the invasive H. halys pest, which consequently modified its salivary proteins. Among the up-regulated proteins, many could be associated with a role in plant defense counteraction, and more especially in allelochemicals detoxification or sequestration. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the atomic composition and the proteome of the salivary proteins adsorbed on the surface of orthodontic metallic bracket. For this, the atomic composition of orthodontic metallic brackets was analyzed with X-ray Photoelectron Spectroscopy (XPS). The acquired bracket pellicle was characterized after brackets were immersed in human whole saliva supernatant for 2 hours at 37°C. Hydroxyapatite (HA) discs were used as a control. Acquired pellicle was harvested from the HA discs (n = 12) and from the metallic brackets (n = 12). Proteomics based on mass spectrometry technology was used for salivary protein identification and characterization. Results showed that most of the proteins adsorbed on the surface of orthodontic metallic brackets and on the HA discs were identified specifically to each group, indicating a small overlapping between the salivary proteins on each study group. A total of 311 proteins present on the HA discs were unique to this group while 253 proteins were unique to metallic brackets, and only 45 proteins were common to the two groups. Even though most proteins were unique to each study group, proteins related to antimicrobial activity, lubrication, and remineralization were present in both groups. These findings demonstrate that the salivary proteins adsorbed on the bracket surface are dependent on the material molecular composition. [ABSTRACT FROM AUTHOR]

This study reports the differences in the protein composition of salivary pellicles formed under in situ conditions on two Titanium (Ti) surfaces, with different roughness and wettability. Smooth pretreatment Ti surfaces (Ti‐PT) with an average roughness (Ra) of 0.45 μm and a water contact angle (WCA) of 92.4°, as well as a more rough sandblasted, large grit, acid‐etched treatment Ti surfaces (Ti‐SLA) with a Ra of 3.3 μm and WCA of 131.8°, were tested. The salivary pellicles were quantitatively analyzed by bicinchoninic acid assays, and the protein identification was performed by Nano‐LC–MS/MS (nano mass spectrometry). Protein levels of 2.5, and 9.1 μg/ml were quantified from the detached salivary pellicle formed on the Ti‐PT and Ti‐SLA surfaces, respectively. Using Nano‐LC–MS/MS, a total of 597 proteins were identified on all the substrates tested; 43 proteins were identified only on the Ti‐PT, and 226 proteins were adsorbed solely on the Ti‐SLA substrates. The physicochemical characteristics of the Ti implant surfaces modified the amount and the identity of the salivary proteome of the pellicles formed, confirming the high selectivity of the protein pellicle formed on a surface once is exposed in the oral cavity. [ABSTRACT FROM AUTHOR]

Interactions between food and saliva govern complex mouthfeel perceptions such as astringency. Herein, we present a study of the interactions of salivary proteins with the main pea protein fractions that are obtained by isoelectric and salt precipitation (legumin-rich, vicilin-rich and albumin-rich fractions). The sensory evaluations performed on protein solutions by trained panelists evidenced that all three protein fractions exhibit a basal level of astringency, but that the albumin fraction was perceived as the most astringent one. All three fractions induced significant but comparable loss of salivary lubrication. Yet, when compared to the other fractions, the albumin fraction showed the formation of a thicker and more rigid film on salivary conditioning film-coated sensors as measured using a quartz crystal microbalance with dissipation monitoring (QCM-D). We also present proteomics studies on the precipitates obtained from the mixtures of saliva and pea protein fractions. Protein identification finds a pool of salivary proteins involved in non-specific interactions with all the three pea protein fractions. Yet, 13 pea proteins specific to the albumin fraction were identified as being involved in specific interactions with salivary proteins. Several of these proteins are part of the plant defense mechanisms and are likely to interact with many salivary proteins. This could explain the higher number of salivary proteins found in the precipitate induced by the albumin fraction when compared to the other two. These quantitative results increase the understanding of the complex links between plant protein-salivary protein interactions and astringency. [Display omitted] • The albumin pea protein fraction was the most astringent pea protein fraction. • Globulin and albumin pea proteins induced a similar salivary lubrication breakdown. • Albumin pea proteins formed a rigid and thick film on a salivary pellicle. • 13 pea proteins of the albumin fraction are likely to trigger interactions with saliva. [ABSTRACT FROM AUTHOR]

Purpose: Pulex irritans are vectors of various zoonotic pathogens. However, molecular studies on P. irritans and flea-borne diseases are limited due to the lack of molecular data. This study aimed to conduct transcriptome sequencing, functional annotation, and pathogen analysis of P. irritans. Methods: Fleas collected from a dog were identified morphologically and molecularly. RNA was extracted for transcriptome sequencing and functional annotation. Open reading frames (ORFs) of unigenes were confirmed by employing bioinformatics strategies, and maximum likelihood (ML) trees were reconstructed based on the highly expressed genes of ejaculation globulin-specific 3-like protein, salivary protein, and actin for phylogenetic relationship analysis. Results: The obtained mitochondrial 16S rRNA gene sequences showed 99.71% of similarity with P. irritans obtained from GenBank database. Transcriptome sequencing generated 74,412 unigenes, of which 53,211 were functionally annotated. A total of 195 unigenes were assigned to fleas, of which 69 contained complete ORFs. Phylogenetic trees of both ejaculatory globulin and salivary protein genes demonstrated that P. irritans first clustered with Pulicidae sp., indicating the reliability of transcriptome data. It is noteworthy that 1070 unigenes were assigned to Hymenolepis microstoma and Dipylidium caninum, of which 62 contained complete ORFs. The phylogenetic tree of the actin gene showed that the unigenes had closer relationships with Echinococcus sp., suggesting the role of P. irritans as intermediate hosts of tapeworms. Conclusion: The results of this study provide the possibility for functional exploration of important genes and lay foundations for the prevention and control of P. irritans and flea-borne diseases. [ABSTRACT FROM AUTHOR]

Alzheimer disease (AD) is the most prevalent neurodegenerative disease in the elderly, characterized by accumulation in the brain of misfolded proteins, inflammation, and oxidative damage leading to neuronal cell death. By considering the viewpoint that AD onset and worsening may be influenced by environmental factors causing infection, oxidative stress, and inflammatory reaction, we investigated the changes of the salivary proteome in a population of patients with respect to that in healthy controls (HCs). Indeed, the possible use of saliva as a diagnostic tool has been explored in several oral and systemic diseases. Moreover, the oral cavity continuously established adaptative and protective processes toward exogenous stimuli. In the present study, qualitative/quantitative variations of 56 salivary proteoforms, including post-translationally modified derivatives, have been analyzed by RP-HPLC-ESI-IT-MS and MS/MS analyses, and immunological methods were applied to validate MS results. The salivary protein profile of AD patients was characterized by significantly higher levels of some multifaceted proteins and peptides that were either specific to the oral cavity or also expressed in other body districts: (i) peptides involved in the homeostasis of the oral cavity; (ii) proteins acting as ROS/RNS scavengers and with a neuroprotective role, such as S100A8, S100A9, and their glutathionylated and nitrosylated proteoforms; cystatin B and glutathionylated and dimeric derivatives; (iii) proteins with antimicrobial activity, such as α-defensins, cystatins A and B, histatin 1, statherin, and thymosin β4, this last with a neuroprotective role at the level of microglia. These results suggested that, in response to injured conditions, Alzheimer patients established defensive mechanisms detectable at the oral level. Data are available via ProteomeXchange with identifier PXD021538. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate whether surface characteristics of different titanium modifications may influence the composition of the salivary pellicle on each surface by analyzing the salivary proteome through mass spectrometry–based proteomics. Materials and methods: Titanium discs with three surfaces modifications (PT (machined titanium), SLA (sandblasted/large-grit/acid-etched), and SLActive (modified SLA)) were characterized (topography, chemistry, and energy) prior to being exposed to saliva for 2 h to form a protein pellicle. The resultant protein layer was retrieved and analyzed through mass spectrometry (nLC-ESI-MS/MS) to examine the surface specificity for protein binding, while the proteome profile of each surface was classified. Results: The proteome analysis showed that the salivary pellicle composition was more complex on rough surfaces (SLA and SLActive). Although variability in protein composition was observed between surfaces, most proteins were detected on more than one surface, indicating a limited surface specificity for protein binding. Additionally, the salivary pellicle formed on the SLActive presented a larger number of proteins associated with immune response, biological adhesion, and biomineralization. Conclusions: Although topography, chemistry, and energy differed between the surfaces, they were not determinant to produce a salivary pellicle with high surface specificity. Also, we showed that several salivary proteins adsorbed on Ti surfaces are involved in biological functions important to the biointegration. Clinical relevance: This study sheds light on the necessity for the development of bioactive surfaces that favors the formation of a specific protein layer that can enhance tissue response to assist the biointegration of dental implants. [ABSTRACT FROM AUTHOR]

Triatomines are hematophagous insects that transmit Trypanosoma cruzi , the etiological agent of Chagas disease. This neglected tropical disease represents a global health issue as it is spreading worldwide. The saliva of Triatominae contains miscellaneous proteins crucial for blood feeding acquisition, counteracting host's hemostasis while performing vasodilatory, anti-platelet and anti-coagulant activities, besides modulating inflammation and immune responses. Since a set of biological processes are mediated by protein complexes, here, the sialocomplexomes (salivary protein complexes) of five species of Triatominae were studied to explore the protein-protein interaction networks. Salivary multiprotein complexes from Triatoma infestans, Triatoma dimidiata, Dipetalogaster maxima, Rhodnius prolixus , and Rhodnius neglectus were investigated by Blue-Native- polyacrylamide gel electrophoresis coupled with liquid chromatography tandem mass spectrometry. More than 70 protein groups, uncovering the landscape of the Triatominae salivary interactome, were revealed. Triabin, actin, thioredoxin peroxidase and an uncharacterized protein were identified in sialocomplexes of the five species, while hexamerin, heat shock protein and histone were identified in sialocomplexes of four species. Salivary proteins related to triatomine immunity as well as those required during blood feeding process such as apyrases, antigen 5, procalins, and nitrophorins compose different complexes. Furthermore, unique proteins for each triatomine species were revealed. This study represents the first Triatominae sialocomplexome reference to date and shows that the approach used is a reliable tool for the analysis of Triatominae salivary proteins assembled into complexes. [ABSTRACT FROM AUTHOR]