NFE2L2/NRF2, OGG1, and cytokine responses of human gingival keratinocytes against oxidative insults of various origin.

OBJECTIVE: Bacterial or tobacco-related insults induce oxidative stress in gingival keratinocytes. The aim of this study was to investigate anti-oxidative and cytokine responses of human gingival keratinocytes (HMK cells) against Porphyromonas gingivalis lipopolysaccharide (Pg LPS), nicotine, and 4-nitroquinoline N-oxide (4-NQO). MATERIALS AND METHODS: HMK cells were incubated with Pg LPS (1 µl/ml), nicotine (1.54 mM), and 4-NQO (1 µM) for 24 h. Intracellular and extracellular levels of interleukin (IL)-1ß, IL-1 receptor antagonist (IL-1Ra), IL-8, monocyte chemoattractant protein (MCP)-1, and vascular endothelial growth factor (VEGF) were measured with the Luminex® xMAP™ technique, and nuclear factor, erythroid 2 like 2 (NFE2L2/NRF2) and 8-oxoguanine DNA glycosylase (OGG1) with Western blots. Data were statistically analyzed by two-way ANOVA with Bonferroni correction. RESULTS: All tested oxidative stress inducers increased intracellular OGG1 levels, whereas only nicotine and 4-NQO induced NFE2L2/NRF2 levels. Nicotine, 4-NQO, and their combinational applications with Pg LPS induced the secretions of IL-1ß and IL-1Ra, while that of IL-8 was inhibited by the presence of Pg LPS. MCP-1 secretion was suppressed by nicotine, alone and together with Pg LPS, while 4-NQO activated its secretion. Treatment of HMK cells with Pg LPS, nicotine, 4-NQO, or their combinations did not affect VEGF levels. CONCLUSION: Pg LPS, nicotine, and 4-NQO induce oxidative stress and regulate anti-oxidative response and cytokine expressions in human gingival keratinocytes differently. These results may indicate that bacterial and tobacco-related insults regulate distinct pathways.

Neonatal handling impairs intradimensional shift and alters plasticity markers in the medial prefrontal cortex of adult rats.

Stress response can be modulated by neonatal/childhood events. Neonatal handling (NH) is an animal model in which the animals are subjected to brief separations from the dam during the first days of life, and it leads to lower emotionality and behavioral changes in adulthood. The aim of this study was to observe if early events, such as (NH), may program associative learning and behavioral flexibility in adult male rats and if these changes could be related to altered neurochemistry in the medial prefrontal cortex (mPFC). We evaluated proteins related to synaptic plasticity (brain-derived neurotrophic factor [BDNF] and synaptophysin [SYP]) as well as Na+/K+-ATPase activity. Additionally, we evaluated proteins related to the dopaminergic system (tyrosine hydroxylase [TH] and phosphorylated TH [pTH]), since this system appears to be affected in some neonatal interventions. Neonatally handled animals exhibited impairment in simple discrimination and intradimensional shift but not in reversal or compound discrimination; in addition, no alteration in switching from an egocentric spatial to a cued strategy was observed. These effects were accompanied by a decrease in SYP levels and Na+/K+-ATPase activity, suggesting reduced synaptic function. These results indicate that NH increases attention to irrelevant stimuli and/or impairs associative learning, and this is accompanied by neurochemical alterations in the (mPFC).

Elevated levels of 8-OHdG and PARK7/DJ-1 in peri-implantitis mucosa.

BACKGROUND: Reactive oxygen species contribute to periodontal tissue homeostasis under control of anti-oxidative responses. Disruption in this balance induces severe inflammation and extended tissue degradation. PURPOSE: Aim of this study was to identify the expression levels of nuclear factor, erythroid 2 like 2 (NFE2L2/NRF2), Parkinsonism associated deglycase (PARK7/DJ-1), kelch-like ECH associated protein 1 (KEAP1), and 8-hydroxy-deoxyguanosine (8-OHdG) in peri-implant mucosal tissues affected by peri-implantitis, and to compare the levels to those of periodontally diseased and healthy tissue samples. METHODS: Tissue biopsies were collected from systemically healthy, non-smoking 12 peri-implantitis patients, 13 periodontitis patients, and 13 periodontally healthy controls. Expression levels of NFE2L2/NRF2, PARK7/DJ-1, KEAP1, and 8-OHdG in tissue samples were analyzed immunohistochemically. Statistical analysis was performed by one-way ANOVA with Tukey's HSD test. RESULTS: Inflammatory cell infiltration in the connective tissue and loss of architecture in the spinous layer of the epithelium were prominent in peri-implantitis. Proportions of 8-OHdG and PARK7/DJ-1 expressing cells were elevated in both peri-implantitis (P = .025 for 8-OHdG and P = .014 for PARK7/DJ-1) and periodontitis (P = .038 for 8-OHdG and P = .012 for PARK7/DJ-1) groups in comparison with controls. Staining intensities of 8-OHdG and PARK7/DJ-1 were higher in the periodontitis and peri-implantitis groups than in the control (P < .01) groups. There was no difference in the expression levels of NFE2L2/NRF2 between the groups. KEAP1 was not observed in any tissue sample. CONCLUSIONS: Peri-implantitis is characterized by severe inflammation and architectural changes in the epithelium and connective tissue. The expressions of 8-OHdG and PARK7/DJ-1 are elevated in both peri-implantitis and periodontitis.

Clostridium Bacteria and Autism Spectrum Conditions: A Systematic Review and Hypothetical Contribution of Environmental Glyphosate Levels.

Nowadays, there seems to be a consensus about the multifactorial nature of autism spectrum disorders (ASD). The literature provides hypotheses dealing with numerous environmental factors and genes accounting for the apparently higher prevalence of this condition. Researchers have shown evidence regarding the impact of gut bacteria on neurological outcomes, altering behavior and potentially affecting the onset and/or severity of psychiatric disorders. Pesticides and agrotoxics are also included among this long list of ASD-related environmental stressors. Of note, ingestion of glyphosate (GLY), a broad-spectrum systemic herbicide, can reduce beneficial bacteria in the gastrointestinal tract microbiota without exerting any effects on the Clostridium population, which is highly resistant to this herbicide. In the present study, (i) we performed a systematic review to evaluate the relationship between Clostridium bacteria and the probability of developing and/or aggravating autism among children. For that purpose, electronic searches were performed on Medline/PubMed and Scielo databases for identification of relevant studies published in English up to December 2017. Two independent researches selected the studies and analyzed the data. The results of the present systematic review demonstrate an interrelation between Clostridium bacteria colonization of the intestinal tract and autism. Finally, (ii) we also hypothesize about how environmental GLY levels may deleteriously influence the gut-brain axis by boosting the growth of Clostridium bacteria in autistic toddlers.

Network-Based Identification of Altered Stem Cell Pluripotency and Calcium Signaling Pathways in Metastatic Melanoma.

Malignancy of cancer has been linked to distinct subsets of stem-like cells, the so-called cancer stem cells (CSCs), which persist during treatment and seem to lead to drug-resistant recurrence. Metastatic spread of cancer cells is one of the hallmarks of malignancy and contributes to most human melanoma-related deaths. Recently, overlapping groups of proteins and pathways were shown to regulate stem cell migration and cancer metastasis, raising the question of whether genes/proteins involved in stem cell pluripotency may have important implications when applied to the biology of cancer metastasis. Furthermore, it is well known that ion channels and receptors, particularly those responsible for calcium (Ca2+) signal generation, are critical in determining the cellular fate of stem cells (SCs). In the present study, we searched for evidence of altered stem cell pluripotency and Ca2+ signaling-related genes in the context of melanoma metastasis. We did this by using network analysis of gene expression in tissue biopsies from three different independent datasets of patients. First, we created an in silico network model ("STEMCa" interactome) showing the landscape of interactions between stem cell pluripotency and Ca2+ signaling-related genes/proteins, and demonstrated that around 51% (151 out of 294) of the genes within this model displayed significant changes of expression (False Discovery Rate (FDR), corrected p-value < 0.05) in at least one of the datasets of melanoma metastasis when compared with primary tumor biopsies (controls). Analysis of the properties (degree and betweenness) of the topological network revealed 27 members as the most central hub (HB) and nonhub-bottlenecks (NH-B) among the 294 genes/proteins of the whole interactome. From those representative genes, CTNNB1, GNAQ, GSK3B, GSTP1, MAPK3, PPP1CC, PRKACA, and SMAD4 showed equal up- or downregulation (corrected p-value < 0.05) in at least 2 independent datasets of melanoma metastases samples and PTPN11 showed upregulation (corrected p-value < 0.05) in three of them when compared with control samples. We postulate that altered expression of stem cell pluripotency and Ca2+ signaling pathway-related genes may contribute to the metastatic transformation, with these central members being an optimal candidate group of biomarkers and in silico therapeutic targets for melanoma metastasis, which deserve further investigation.

Supplementation with Achyrocline satureioides Inflorescence Extracts to Pregnant and Breastfeeding Rats Induces Tissue-Specific Changes in Enzymatic Activity and Lower Neonatal Survival.

Achyrocline satureioides (AS, family Asteraceae) is a plant widely used in traditional medicine for stomach, digestive, and gastrointestinal disorders during pregnancy. Studies regarding the indiscriminate use of plant infusions during pregnancy are limited. Recent reports have shown that chronic flavonoid supplementation induces toxicity in vivo and raises the mortality rates of healthy subjects. Therefore, we investigated whether supplementation of pregnant and lactating Wistar rats with two AS inflorescence extracts, consisting of an aqueous (AQ) extract similar to a tea (47 mg·kg-1·day) and a hydroethanolic (HA) extract (35 mg·kg-1·day-1) with a higher flavonoid content, could induce redox-related side effects. Total reactive antioxidant potential (TRAP), thiobarbituric reactive species (TBARS), and total reduced thiol (SH) content were evaluated. Superoxide dismutase (SOD) and catalase (CAT) activities were additionally quantified. Our data suggest that both AQ and HA of AS inflorescence extracts may induce symptoms of toxicity in concentrations of (47 mg·kg-1·day) and (35 mg·kg-1·day-1), respectively, in mothers regarding the delivery index and further decrease of neonatal survival. Of note, significant tissue-specific changes in maternal (liver, kidney, heart, and hippocampus) and pups (liver and kidney) biochemical oxidative parameters were observed. Our findings provide evidence that may support the need to control supplementation with the AQ of AS inflorescence extracts during gestation due to potential toxicity in vivo, which might be related, at least in part, to changes in tissue-specific redox homeostasis and enzymatic activity.

Effect of Paullinia cupana Mart. Commercial Extract During the Aging of Middle Age Wistar Rats: Differential Effects on the Hippocampus and Striatum.

During aging, there is a marked decline in the antioxidant capacity of brain tissue, leading to a gradual loss of the antioxidant/oxidant balance, which causes oxidative damage. The effects of Paullinia cupana Mart. extract, which is described as being rich in caffeine and many polyphenol compounds, on the central nervous system have not been extensively investigated. The aim of this study was to therefore investigate the effect of a commercial guarana extract (CGE) on cognitive function, oxidative stress, and brain homeostasis proteins related to cognitive injury and senescence in middle age, male Wistar rats. Animals were randomly assigned to a group according to their treatment (saline, CGE, or caffeine). Solutions were administered daily by oral gavage for 6 months. Open field and novel object recognition tasks were performed before and after treatment. Biochemical analyses were carried out on the hippocampus and striatum. Our open field data showed an increase in exploratory activity and a decrease in anxiety-like behavior with caffeine but not with the CGE treatment. In the CGE-treated group, catalase activity decreased in the hippocampus and increased in the striatum. Analyses of the hippocampus and striatum indicate that CGE and/or caffeine altered some of the analyzed parameters in a tissue-specific manner. Our data suggest that CGE intake does not improve cognitive development, but modifies the oxidative stress machinery and neurodegenerative-signaling pathway, inhibiting pro-survival pathway molecules in the hippocampus and striatum. This may contribute to the development of unfavorable microenvironments in the brain and neurodegenerative disorders.

Effects of Achyrocline satureioides Inflorescence Extracts against Pathogenic Intestinal Bacteria: Chemical Characterization, In Vitro Tests, and In Vivo Evaluation.

Three Achyrocline satureioides (AS) inflorescences extracts were characterized: (i) a freeze-dried extract prepared from the aqueous extractive solution and (ii) a freeze-dried and (iii) a spray-dried extract prepared from hydroethanol extractive solution (80% ethanol). The chemical profile, antioxidant potential, and antimicrobial activity against intestinal pathogenic bacteria of AS extracts were evaluated. In vitro antioxidant activity was determined by the total reactive antioxidant potential (TRAP) assay. In vivo analysis and characterization of intestinal microbiota were performed in male Wistar rats (saline versus treated animals with AS dried extracts) by high-throughput sequencing analysis: metabarcoding. Antimicrobial activity was tested in vitro by the disc diffusion tests. Moisture content of the extracts ranged from 10 to 15% and 5.7 to 17 mg kg-1 of fluorine. AS exhibited antioxidant activity, especially in its freeze-dried form which also exhibited a wide spectrum of antimicrobial activity against intestinal pathogenic bacteria greater than those observed by the antibiotic, amoxicillin, when tested against Bacillus cereus and Staphylococcus aureus. Antioxidant and antimicrobial activities of AS extracts seemed to be positively correlated with the present amount of flavonoids. These findings suggest a potential use of AS as a coadjuvant agent for treating bacterial-induced intestinal diseases with high rates of antibiotic resistance.

Changes in Cell Cycle and Up-Regulation of Neuronal Markers During SH-SY5Y Neurodifferentiation by Retinoic Acid are Mediated by Reactive Species Production and Oxidative Stress.

Human neuroblastoma SH-SY5Y cells have been used as an in vitro model for neurodegenerative disorders such as Parkinson's disease and can be induced to a mature neuronal phenotype through retinoic acid (RA) differentiation. However, mechanisms of RA-induced differentiation remain unclear. Here, we investigate the role of reactive species (RS) on SH-SY5Y neuroblastoma cells under RA differentiation, using the antioxidant Trolox® as co-treatment. We found that RA treatment for 7 days reduced the cell number and proliferative capacity and induced the expression of adult catecholaminergic/neuronal markers such as tyrosine hydroxylase (TH), ß-III tubulin, and enolase-2. Evaluation of intracellular RS production by DCFH oxidation assay and quantification of cell non-enzymatic antioxidant activity by TRAP demonstrated that RA increases RS production. Furthermore, mitochondrial NADH oxidation showed to be inhibited under differentiation with RA. Cells subjected to co-treatment with antioxidant Trolox® demonstrated a remaining proliferative capacity and a decrease in the pro-oxidant state and RS production. Besides, antioxidant treatment restores the mitochondrial NADH oxidation. Importantly, Trolox® co-treatment inhibited the appearance of morphological characteristics such as neurite extension and branching, and decreased the expression of TH, ß-III tubulin, and enolase-2 after a seven-day differentiation with RA, indicating that RS production is a necessary step in this process. Trolox® also inhibited the phosphorylation of Akt and ERK1/2, which are involved in differentiation and survival, respectively, of these cells. Altogether, these data indicate the presence of a redox-dependent mechanism in SH-SY5Y RA-differentiation process and can be a useful insight to improve understanding of neuronal differentiation signaling.

Analyses of Gingival Adhesion Molecules in Periodontitis: Theoretical In Silico, Comparative In Vivo, and Explanatory In Vitro Models.

BACKGROUND: A deeper understanding of periodontitis pathophysiology is central to future development of novel biomarkers and therapeutics. The following is reported here: 1) an in silico network model of interactions among cell adhesion molecules and a network-focused microarray analysis of the corresponding genes in periodontitis; 2) analysis of secretions of adhesion molecules in gingival tissue samples from patients with periodontitis and healthy controls; and 3) effect of the human neutrophilic peptide-1 (HNP-1) on epithelial adhesion molecules. METHODS: The network model identified 85 nodes in relation to the interactions of adhesion molecules. Subsequently, the relative gene expression was overlaid on the network model. Differential gene expression was analyzed, and false discovery rate control was performed for statistical assessment of the microarray data. Both tissue and cell culture samples were immunostained for desmocollin (DSC)2, occludin (OCLN), desmoglein (DSG)1, tight junction protein 2, and gap junction protein α. RESULTS: The differential gene expression analysis revealed that the epithelial adhesion molecules were significantly lower in abundance in individuals with periodontitis than controls. In contrast, the genes for leukocyte adhesion molecules showed a significant upregulation. Immunostainings revealed elevated secretions of both DSG1 and OCLN in periodontitis. An in vitro model suggested reduced DSC2 and OCLN secretions in the presence of HNP-1. CONCLUSIONS: Gene expression of gingival adhesion molecules in periodontitis is regulated by leukocyte transmigration, whereas the neutrophilic antimicrobial peptide HNP-1 is noted as a putative regulator of epithelial adhesion molecules. These observations contribute to the key mechanisms by which future biomarkers might be developed for periodontitis.

Calcium signalling toolkits in astrocytes and spatio-temporal progression of Alzheimer's disease.

Pathological remodelling of astroglia represents an important component of the pathogenesis of Alzheimer's disease (AD). In AD astrocytes undergo both atrophy and reactivity; which may be specific for different stages of the disease evolution. Astroglial reactivity represents the generic defensive mechanism, and inhibition of astrogliotic response exacerbates b-amyloid pathology associated with AD. In animal models of AD astroglial reactivity is different in different brain regions, and the deficits of reactive response observed in entorhinal and prefrontal cortices may be linked to their vulnerability to AD progression. Reactive astrogliosis is linked to astroglial Ca(2+) signalling, this latter being widely regarded as a mechanism of astroglial excitability. The AD pathology evolving in animal models as well as acute or chronic exposure to ß-amyloid induce pathological remodelling of Ca(2+) signalling toolkit in astrocytes. This remodelling modifies astroglial Ca(2+) signalling and may be linked to cellular mechanisms of AD pathogenesis.

Neonatal handling causes impulsive behavior and decreased pharmacological response to methylphenidate in male adult wistar rats.

Neonatal handling has an impact on adult behavior of experimental animals and is associated with rapid and increased palatable food ingestion, impaired behavioral flexibility, and fearless behavior to novel environments. These symptoms are characteristic features of impulsive trait, being controlled by the medial prefrontal cortex (mPFC). Impulsive behavior is a key component of many psychiatric disorders such as attention deficit hyperactivity disorder (ADHD), manic behavior, and schizophrenia. Others have reported a methylphenidate (MPH)-induced enhancement of mPFC functioning and improvements in behavioral core symptoms of ADHD patients. The aims of the present study were: (i) to find in vivo evidence for an association between neonatal handling and the development of impulsive behavior in adult Wistar rats and (ii) to test whether neonatal handling could have an impact on monoamine levels in the mPFC and the pharmacological response to MPH in vivo. Therefore, experimental animals (litters) were classified as: "non-handled" and "handled" (10[Formula: see text]min/day, postnatal days 1-10). After puberty, they were exposed to either a larger and delayed or smaller and immediate reward (tolerance to delay of reward task). Acute MPH (3[Formula: see text]mg/Kg. i.p.) was used to suppress and/or regulate impulsive behavior. Our results show that only neonatally handled male adult Wistar rats exhibit impulsive behavior with no significant differences in monoamine levels in the medial prefrontal cortex, together with a decreased response to MPH. On this basis, we postulate that early life interventions may have long-term effects on inhibitory control mechanisms and affect the later response to pharmacological agents during adulthood.

Up-Regulation of Oligodendrocyte Lineage Markers in the Cerebellum of Autistic Patients: Evidence from Network Analysis of Gene Expression.

Autism is a neurodevelopmental disorder manifested by impaired social interaction, deficits in communication skills, restricted interests, and repetitive behaviors. In neurodevelopmental, neurodegenerative, and psychiatric disorders, glial cells undergo morphological, biochemical, and functional rearrangements, which are critical for neuronal development, neurotransmission, and synaptic connectivity. Cerebellar function is not limited to motor coordination but also contributes to cognition and may be affected in autism. Oligodendrocytes and specifically oligodendroglial precursors are highly susceptible to oxidative stress and excitotoxic insult. In the present study, we searched for evidence for developmental oligodendropathy in the context of autism by performing a network analysis of gene expression of cerebellar tissue. We created an in silico network model (OLIGO) showing the landscape of interactions between oligodendrocyte markers and demonstrated that more than 50 % (16 out of 30) of the genes within this model displayed significant changes of expression (corrected p value <0.05) in the cerebellum of autistic patients. In particular, we found up-regulation of OLIG2-, MBP-, OLIG1-, and MAG-specific oligodendrocyte markers. We postulate that aberrant expression of oligodendrocyte-specific genes, potentially related to changes in oligodendrogenesis, may contribute to abnormal cerebellar development, impaired myelination, and anomalous synaptic connectivity in autism spectrum disorders (ASD).

Two Cheers for Crohn's Disease and Periodontitis: Beta-Defensin-2 as an Actionable Target to Intervene on Two Clinically Distinct Diseases.

Recent advances in multi-omics approaches encompassing genomics, transcriptomics, proteomics, and metabolomics offer hitherto unprecedented insights on common complex human diseases. A unique angle pertinent for both diagnostic and therapeutic sciences involves rethinking clinically distinct diseases with a view to their shared molecular targets, interactomes, and pathophysiologies. Reflecting at a scale of disease-to-disease associations might help clinicians, public health practitioners, drug and biotechnology developers, and associated knowledge industries in the current era. This review article examines the hypothesis that "Intersecting Molecular Pathways Permit Interventions on Multiple Clinical Endpoints", thus uniquely bringing together Crohn's disease and periodontitis. Furthermore, we propose a novel connector molecular target between these two ostensibly distinct diseases at a clinical level, human beta defensin (hBD)-2, and suggest pathways by which hBD-2 can conceivably connect Crohn's disease and periodontitis by virtue of regulating the innate-immune response. We conclude by emphasizing different approaches where hBD-2 can be employed as a diagnostic and therapeutic tool to improve the quality of life of susceptible individuals and minimize the economic costs of these two major global public health problems. The strategy presented here also presents potentials for targeting of multiple diseases through a unique "nodal molecular target" that "speaks to" multiple clinical endpoints.

In Vitro Neuroprotective Effect of Shikimic Acid Against Hydrogen Peroxide-Induced Oxidative Stress.

Shikimic acid (SA), originally extracted from Illicium verum Hook. fil., is an indispensable starting material for the synthesis of the antiviral drug Oseltamivir (Tamiflu(®)) with very limited number of studies regarding its biological effects in vitro. Therefore, we here evaluated the thermoanalytical profile, redox properties, and in vitro effects of SA on human neuronal-like cells (SH-SY5Y). The thermoanalytical profile of SA was studied by using differential scanning calorimetry (DSC) and thermogravimetry/derivative thermogravimetry (TG/DTG) characterization. Both antioxidant potential and in vitro lipoperoxidation levels were analyzed. Cell viability and intracellular reactive species (RS) production was determined by DCF and SRB assays, respectively. Our results show in vitro antioxidant activity of SA without exerting cytotoxic effects on SH-SY5Y cells at tested concentrations of 10 nM, 10 µM, and 10 mM. In addition, SA protected the cells against H2O2-induced toxicity; effect that could be related, at least in part, with decreased intracellular RS production and its antioxidant potential. The present study shows evidence for neuroprotective actions of SA against oxidative stress-induced toxicity on SH-SY5Y cells, inviting for further investigation about its potential use in the context of oxidative stress-associated neurodegenerative diseases.

Chronic retinyl palmitate supplementation to middle-aged Wistar rats disrupts the brain redox homeostasis and induces changes in emotional behavior.

SCOPE: Aging process makes older adults especially vulnerable to neurodegeneration and mental disorders. Overconsumption-related neurotoxic effects of certain dietary nutrients by older population could represent a contribution factor for the development of neuropsychiatric conditions by this subpopulation. Thus, we here investigated whether chronic supplementation with retinyl palmitate, at doses commonly found in vitamin supplements (300, 600, and 3000 mcg of RAE/kg/day), could have an impact on emotional behavior of middle-aged Wistar rats. METHODS AND RESULTS: We report that supplementation with retinyl palmitate for 28 days induces an altered emotional state of middle-aged Wistar rats and oxidative stress in cerebellum, cerebral cortex, hippocampus, and striatum, associated with imbalance of enzymatic antioxidant defenses, decrease in non-enzymatic antioxidant defenses, and increase in protein and lipid damages. CONCLUSION: Our data show evidence for (i) changes in emotional reactivity, similar to anxiety, in middle-aged rats chronically supplemented with retinyl palmitate; and (ii) suggest a possible interrelation between pro-oxidant events in the brain and these differences in the behavioral profile that cannot be attributed to hepatotoxicity. Our results invite for additional studies to further investigate such interrelation.

A Systems Biology Approach to Reveal Putative Host-Derived Biomarkers of Periodontitis by Network Topology Characterization of MMP-REDOX/NO and Apoptosis Integrated Pathways.

Periodontitis, a formidable global health burden, is a common chronic disease that destroys tooth-supporting tissues. Biomarkers of the early phase of this progressive disease are of utmost importance for global health. In this context, saliva represents a non-invasive biosample. By using systems biology tools, we aimed to (1) identify an integrated interactome between matrix metalloproteinase (MMP)-REDOX/nitric oxide (NO) and apoptosis upstream pathways of periodontal inflammation, and (2) characterize the attendant topological network properties to uncover putative biomarkers to be tested in saliva from patients with periodontitis. Hence, we first generated a protein-protein network model of interactions ("BIOMARK" interactome) by using the STRING 10 database, a search tool for the retrieval of interacting genes/proteins, with "Experiments" and "Databases" as input options and a confidence score of 0.400. Second, we determined the centrality values (closeness, stress, degree or connectivity, and betweenness) for the "BIOMARK" members by using the Cytoscape software. We found Ubiquitin C (UBC), Jun proto-oncogene (JUN), and matrix metalloproteinase-14 (MMP14) as the most central hub- and non-hub-bottlenecks among the 211 genes/proteins of the whole interactome. We conclude that UBC, JUN, and MMP14 are likely an optimal candidate group of host-derived biomarkers, in combination with oral pathogenic bacteria-derived proteins, for detecting periodontitis at its early phase by using salivary samples from patients. These findings therefore have broader relevance for systems medicine in global health as well.