scholarly journals Neutrophils Orchestrate the Periodontal Pocket

2021 ◽  
Vol 12 ◽  
Author(s):  
Ljubomir Vitkov ◽  
Luis E. Muñoz ◽  
Janina Schoen ◽  
Jasmin Knopf ◽  
Christine Schauer ◽  
...  
Keyword(s):  
Regional Differences ◽  
Late Onset ◽  
Neutrophil Extracellular Trap ◽  
Periodontal Pocket ◽  
Oral Microbiota ◽  
Tooth Surfaces ◽  
Molecular Patterns ◽  
Neutrophil Response ◽  
Stimulation Of

The subgingival biofilm attached to tooth surfaces triggers and maintains periodontitis. Previously, late-onset periodontitis has been considered a consequence of dysbiosis and a resultant polymicrobial disruption of host homeostasis. However, a multitude of studies did not show “healthy” oral microbiota pattern, but a high diversity depending on culture, diets, regional differences, age, social state etc. These findings relativise the aetiological role of the dysbiosis in periodontitis. Furthermore, many late-onset periodontitis traits cannot be explained by dysbiosis; e.g. age-relatedness, attenuation by anti-ageing therapy, neutrophil hyper-responsiveness, and microbiota shifting by dysregulated immunity, yet point to the crucial role of dysregulated immunity and neutrophils in particular. Furthermore, patients with neutropenia and neutrophil defects inevitably develop early-onset periodontitis. Intra-gingivally injecting lipopolysaccharide (LPS) alone causes an exaggerated neutrophil response sufficient to precipitate experimental periodontitis. Vice versa to the surplus of LPS, the increased neutrophil responsiveness characteristic for late-onset periodontitis can effectuate gingiva damage likewise. The exaggerated neutrophil extracellular trap (NET) response in late-onset periodontitis is blameable for damage of gingival barrier, its penetration by bacteria and pathogen-associated molecular patterns (PAMPs) as well as stimulation of Th17 cells, resulting in further neutrophil activation. This identifies the dysregulated immunity as the main contributor to periodontal disease.

scholarly journals An Insight into the Role of Benefical Bacteria in Periodontal Pocket Recolonization: A Literature Review

2014 ◽  
Vol 8 (1) ◽  
pp. 47-50
Author(s):  
SM Apoorva ◽  
A Suchetha ◽  
DB Mundinamane ◽  
DP Bhopale ◽  
A Bharwani ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Periodontal Pocket ◽  
Human Beings ◽  
Beneficial Bacteria ◽  
Initial Attachment ◽  
Bacterial Interactions ◽  
Tooth Surfaces ◽  
Free People ◽  
Insight Into

ABSTRACT Microflora can be found in both caries-free and periodontitis-free people and caries-affected and periodontitis-affected people, and many clinical studies reveal that the portion of certain bacterial species such as Streptococcus mutans or Porphyromonas gingivalis, respectively, is increased in patients with caries or periodontitis. Therefore, it seems that the competition that results between beneficial bacteria and virulent bacteria leads to either a healthy or sick status of human beings. Competition between members of the dental microflora and there role in pocket recolonization is very complex and many antagonistic characteristics can be observed from competition for initial attachment on tooth surfaces or for later attachment to pioneer bacteria, competition from bacteriocins or hydrogen peroxide secreted and from facilitating the growth of some species which inhibit other species. To date only some of the details of these mechanisms are known. The present review will provide an overview on the prevalence of beneficial bacteria and the major mechanisms of oral bacterial interactions. Due to the large number of oral bacterial species, only the best characterized species are included in this review.

scholarly journals Role of Damage-Associated Molecular Patterns and Uncontrolled Inflammation in Pediatric Sepsis-Induced Multiple Organ Dysfunction Syndrome

2018 ◽  
Vol 08 (01) ◽  
pp. 025-031 ◽  
Author(s):  
Diana Pang ◽  
Dalia Bashir ◽  
Joseph Carcillo ◽  
Trung Nguyen ◽  
Rajesh Aneja ◽  
...  
Keyword(s):  
Organ Dysfunction ◽  
Multiple Organ Dysfunction Syndrome ◽  
Multiple Organ ◽  
Multiple Organ Dysfunction ◽  
Risk Of Death ◽  
Pediatric Sepsis ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Stimulation Of

AbstractThe incidence of multiple organ dysfunction syndrome (MODS) in sepsis varies from 17 to 73% and furthermore, increases the risk of death by 60% when controlled for the number of dysfunctional organs. Several MODS phenotypes exist, each unique in presentation and pathophysiology. Common to the phenotypes is the stimulation of the immune response by pathogen-associated molecular patterns (PAMPs), or danger-associated molecular patterns (DAMPs) causing an unremitting inflammation. Two of the MODS phenotypes are discussed in detail, thrombocytopenia-associated multiple organ failure (TAMOF) and the hyperinflammatory phenotype–macrophage activating syndrome (MAS) and hemophagocytic lymphohistiocytosis (HLH). In the end, we will briefly review the role of mitochondrial dysfunction as a significant contributor to the pathogenesis of MODS.

The significance of Toll-like receptors in selected nephropathies

2019 ◽  
Vol 55 (2) ◽  
pp. 107-112
Author(s):  
Sebastian Mertowski ◽  
Ewelina Grywalska ◽  
Jarosław Ludian ◽  
Agnieszka Grafka ◽  
Barbara Pęksa ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Inflammatory Reaction ◽  
Inflammatory Mediators ◽  
Modern Society ◽  
Kidney Damage ◽  
Toll Like Receptors ◽  
Molecular Patterns ◽  
Stimulation Of

The diseases associated with kidney damage are an increasingly common problem in modern society and complications of chronic renal failure can result in death. Research conducted by many scientific centers, both Polish and foreign, concern the search for possible factors involved in the pathogenesis of glomerulonephritis. One of the possible causes of nephropathy may include the dysfunction of Toll-like receptors (TLRs), which constitute a “bridge” between innate and acquired response. TLRs are involved in receiving signals related to pathogen associated molecular patterns (PAMPs) as well as receiving information related to the danger associated molecular patterns (DAMP). The stimulation of these receptors activates a cascade of reactions in the course of which various mediators, including pro-inflammatory mediators, are produced. The resulting long-lasting inflammation that develops within the glomerulus may cause kidney damage. In both nephropathies caused by excessive production of antibodies in the IgA class, as well as nephropathy induced by diabetes or lupus, the expression of individual TLRs may indicate an inducer of an inflammatory reaction cascade that leads to kidney damage. This article focuses on literature reports that present current views on the role of TLRs in the pathogenesis of the most common nephropathies.

scholarly journals Early and Late Processes Driving NET Formation, and the Autocrine/Paracrine Role of Endogenous RAGE Ligands

2021 ◽  
Vol 12 ◽  
Author(s):  
Olga Tatsiy ◽  
Vanessa de Carvalho Oliveira ◽  
Hugo Tshivuadi Mosha ◽  
Patrick P. McDonald
Keyword(s):  
Signaling Pathways ◽  
Neutrophil Extracellular Trap ◽  
Net Generation ◽  
Human Neutrophils ◽  
Chromatin Decondensation ◽  
Cellular Processes ◽  
Activated Neutrophils ◽  
Arginine Residues ◽  
Neutrophil Response

Neutrophil extracellular trap (NET) formation has emerged as an important response against various pathogens; it also plays a role in chronic inflammation, autoimmunity, and cancer. Despite a growing understanding of the mechanisms underlying NET formation, much remains to be elucidated. We previously showed that in human neutrophils activated with different classes of physiological stimuli, NET formation features both early and late events that are controlled by discrete signaling pathways. However, the nature of these events has remained elusive. We now report that PAD4 inhibition only affects the early phase of NET generation, as do distinct signaling intermediates (TAK1, MEK, p38 MAPK). Accordingly, the inducible citrullination of residue R2 on histone H3 is an early neutrophil response that is regulated by these kinases; other arginine residues on histones H3 and H4 do not seem to be citrullinated. Conversely, elastase blockade did not affect NET formation by several physiological stimuli, though it did so in PMA-activated cells. Among belated events in NET formation, we found that chromatin decondensation is impaired by the inhibition of signaling pathways controlling both early and late stages of the phenomenon. In addition to chromatin decondensation, other late processes were uncovered. For instance, unstimulated neutrophils can condition themselves to be poised for rapid NET induction. Similarly, activated neutrophils release endogenous proteic factors that promote and largely mediate NET generation. Several such factors are known RAGE ligands and accordingly, RAGE inbibition largely prevents both NET formation and the conditioning of neutrophils to rapidly generate NETs upon stimulation. Our data shed new light on the cellular processes underlying NET formation, and unveil unsuspected facets of the phenomenon that could serve as therapeutic targets. In view of the involvement of NETs in both homeostasis and several pathologies, our findings are of broad relevance.

scholarly journals Interactions Between Neutrophils and Periodontal Pathogens in Late-Onset Periodontitis

2021 ◽  
Vol 11 ◽  
Author(s):  
Qingsong Jiang ◽  
Yuxi Zhao ◽  
Yusen Shui ◽  
Xuedong Zhou ◽  
Lei Cheng ◽  
...  
Keyword(s):  
Late Onset ◽  
Neutrophil Recruitment ◽  
Neutrophil Extracellular Trap ◽  
Periodontal Pocket ◽  
Junctional Epithelium ◽  
Periodontal Pathogens ◽  
Inflammatory Reactions ◽  
Periodontal Tissues ◽  
Microbial Invasion ◽  
Excessive Activation

Late-onset periodontitis is associated with a series of inflammatory reactions induced by periodontal pathogens, such as Porphyromonas gingivalis, a keystone pathogen involved in periodontitis. Neutrophils are the most abundant leukocytes in the periodontal pocket/gingival crevice and inflamed periodontal tissues. They form a “wall” between the dental plaque and the junctional epithelium, preventing microbial invasion. The balance between neutrophils and the microbial community is essential to periodontal homeostasis. Excessive activation of neutrophils in response to periodontal pathogens can induce tissue damage and lead to periodontitis persistence. Therefore, illuminating the interactions between neutrophils and periodontal pathogens is critical for progress in the field of periodontitis. The present review aimed to summarize the interactions between neutrophils and periodontal pathogens in late-onset periodontitis, including neutrophil recruitment, neutrophil mechanisms to clear the pathogens, and pathogen strategies to evade neutrophil-mediated elimination of bacteria. The recruitment is a multi-step process, including tethering and rolling, adhesion, crawling, and transmigration. Neutrophils clear the pathogens mainly by phagocytosis, respiratory burst responses, degranulation, and neutrophil extracellular trap (NET) formation. The mechanisms that pathogens activate to evade neutrophil-mediated killing include impairing neutrophil recruitment, preventing phagocytosis, uncoupling killing from inflammation, and resistance to ROS, degranulation products, and NETs.

Stimulation of Ca(2+)-dependent exocytosis of the sperm acrosome by cAMP acting downstream of phospholipase A2

Reproduction ◽  
2000 ◽  
pp. 57-68 ◽  
Author(s):  
J Garde ◽  
ER Roldan
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Phosphodiesterase Inhibitors ◽  
Dibutyryl Camp ◽  
Camp Phosphodiesterase ◽  
Ram Sperm ◽  
Camp Formation ◽  
Stimulation Of

Spermatozoa undergo exocytosis in response to agonists that induce Ca2+ influx and, in turn, activation of phosphoinositidase C, phospholipase C, phospholipase A2, and cAMP formation. Since the role of cAMP downstream of Ca2+ influx is unknown, this study investigated whether cAMP modulates phospholipase C or phospholipase A2 using a ram sperm model stimulated with A23187 and Ca2+. Exposure to dibutyryl-cAMP, phosphodiesterase inhibitors or forskolin resulted in enhancement of exocytosis. However, the effect was not due to stimulation of phospholipase C or phospholipase A2: in spermatozoa prelabelled with [3H]palmitic acid or [14C]arachidonic acid, these reagents did not enhance [3H]diacylglycerol formation or [14C]arachidonic acid release. Spermatozoa were treated with the phospholipase A2 inhibitor aristolochic acid, and dibutyryl-cAMP to test whether cAMP acts downstream of phospholipase A2. Under these conditions, exocytosis did not occur in response to A23187 and Ca2+. However, inclusion of dibutyryl-cAMP and the phospholipase A2 metabolite lysophosphatidylcholine did result in exocytosis (at an extent similar to that seen when cells were treated with A23187/Ca2+ and without the inhibitor). Inclusion of lysophosphatidylcholine alone, without dibutyryl-cAMP, enhanced exocytosis to a lesser extent, demonstrating that cAMP requires a phospholipase A2 metabolite to stimulate the final stages of exocytosis. These results indicate that cAMP may act downstream of phospholipase A2, exerting a regulatory role in the exocytosis triggered by physiological agonists.

Exploring the Role of Aggregated Proteomes in the Pathogenesis of Alzheimer’s Disease

2020 ◽  
Vol 21 (12) ◽  
pp. 1164-1173
Author(s):  
Siju Ellickal Narayanan ◽  
Nikhila Sekhar ◽  
Rajalakshmi Ganesan Rajamma ◽  
Akash Marathakam ◽  
Abdullah Al Mamun ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Early Onset ◽  
Late Onset ◽  
Precursor Protein ◽  
Brain Disorder ◽  
Amyloid Aβ ◽  
T Tau

: Alzheimer’s disease (AD) is a progressive brain disorder and one of the most common causes of dementia and death. AD can be of two types; early-onset and late-onset, where late-onset AD occurs sporadically while early-onset AD results from a mutation in any of the three genes that include amyloid precursor protein (APP), presenilin 1 (PSEN 1) and presenilin 2 (PSEN 2). Biologically, AD is defined by the presence of the distinct neuropathological profile that consists of the extracellular β-amyloid (Aβ) deposition in the form of diffuse neuritic plaques, intraneuronal neurofibrillary tangles (NFTs) and neuropil threads; in dystrophic neuritis, consisting of aggregated hyperphosphorylated tau protein. Elevated levels of (Aβ), total tau (t-tau) and phosphorylated tau (ptau) in cerebrospinal fluid (CSF) have become an important biomarker for the identification of this neurodegenerative disease. The aggregation of Aβ peptide derived from amyloid precursor protein initiates a series of events that involve inflammation, tau hyperphosphorylation and its deposition, in addition to synaptic dysfunction and neurodegeneration, ultimately resulting in dementia. The current review focuses on the role of proteomes in the pathogenesis of AD.

scholarly journals Flavonoids Ameliorate Stress-Induced Depression by Preventing NLRP3 Inflammasome Priming

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1231-1231
Author(s):  
Giulio Pasinetti
Keyword(s):  
Mrna Expression ◽  
Chronic Stress ◽  
Nlrp3 Inflammasome ◽  
Signaling Cascades ◽  
Dietary Polyphenols ◽  
Funding Sources ◽  
Glycation End Products ◽  
Molecular Patterns

Abstract Objectives Chronic stress activates danger-associated molecular patterns (DAMPs), stimulating the NLRP3 inflammasome. NLRP3 activation triggers the release of pro-inflammatory cytokine IL-1β. The activity of the NLRP3 inflammasome propagates pro-inflammatory signaling cascades implicated in the onset of depression. Our previous studies show that polyphenolic compounds were found to ameliorate stress induced depression in mouse models. However, the relevant mechanism has not been identified. This study examined the effect of administering polyphenols on DAMP signaling in enriched mice microglia. Methods This study examined the effect of administering polyphenols on DAMP signaling in mice microglia. To recapitulate stress-induced depression, mice underwent chronic unpredictable stress (CUS). Microglia were isolated at various time points throughout the CUS protocol. We also assessed long-term persistent changes after CUS and susceptibility to subthreshold unpredictable stress (US) re-exposure. Results Interestingly, the development of US – induced depression and anxiety depended upon a previous exposure to CUS. We found that CUS caused robust upregulation of IL-1β mRNA in enriched microglia, an effect that persists for up to 4 weeks following CUS exposure. Following the subthreshold US re-exposure, we observed the upregulation of pro- IL-1β as well as pro-receptor for advanced glycation end products (RAGE). Toll-like receptor 4 (TLR-4) was not. We also observed an increase in RAGE mRNA expression when mice were exposed to US prior to the start of the CUS paradigm. Importantly, a primary exposure to US, was sufficient to increase RAGE mRNA expression. We found that polyphenol administration significantly improved CUS-induced depressive-like phenotypes and also reversed neuroinflammation in mice. Treatment with dietary flavonoids prevented upregulation of IL-1β, RAGE mRNA, which reflects the ability of polyphenols that may have begun following the primary exposure to US. Conclusions Taken all together, the results provide evidence of the role of dietary polyphenols in preventing persistent microglial activation, which has been shown to result in reduced long term vulnerability to depressive-like behaviors following expose to chronic stress. Funding Sources This study was supported by a P50 CARBON Center grant from the NCCIH/ODS.

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