scholarly journals Association of Porphyromonas Gingivalis, a Major Periodontopathic Bacteria, in Patients with Alzheimer's Disease

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
C Blanc ◽  
P López-Jarana ◽  
B Amaral ◽  
M Relvas
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Periodontopathic Bacteria

scholarly journals Potential Role of Phosphoglycerol Dihydroceramide Produced by Periodontal Pathogen Porphyromonas gingivalis in the Pathogenesis of Alzheimer’s Disease

2020 ◽  
Vol 11 ◽  
Author(s):  
Chiaki Yamada ◽  
Juliet Akkaoui ◽  
Anny Ho ◽  
Carolina Duarte ◽  
Richard Deth ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Virulence Factors ◽  
Potential Role ◽  
Sirtuin 1 ◽  
Periodontal Pathogen ◽  
Secretory Phenotype ◽  
Aβ42 Peptide

BackgroundAmong different types of sphingolipids produced by human cells, the possible engagement of ceramide species in the pathogenesis of Alzheimer’s disease (AD) has attracted recent attention. While ceramides are primarily generated by de novo synthesis in mammalian cells, only a limited number of bacterial species, produce ceramides, including phosphoglycerol dihydroceramide (PGDHC) that is produced by the key periodontal pathogen Porphyromonas gingivalis. Emerging evidence indicates that virulence factors produced by P. gingivalis, such as lipopolysaccharide and gingipain, may be engaged in the initiation and/or progression of AD. However, the potential role of PGDHC in the pathogenesis of AD remains unknown. Therefore, the aim of this study was to evaluate the influence of PGDHC on hallmark findings in AD.Material and MethodsCHO-7WD10 and SH-SY-5Y cells were exposed to PGDHC and lipopolysaccharide (LPS) isolated from P. gingivalis. Soluble Aβ42 peptide, amyloid precursor protein (APP), phosphorylated tau and senescence-associated secretory phenotype (SASP) factors were quantified using ELISA and Western blot assays. ResultsOur results indicate that P. gingivalis (Pg)-derived PGDHC, but not Pg-LPS, upregulated secretion of soluble Aβ42 peptide and expression of APP in CHO-7WD10 cells. Furthermore, hyperphosphorylation of tau protein was observed in SH-SY-5Y cells in response to PGDHC lipid. In contrast, Pg-LPS had little, or no significant effect on the tau phosphorylation induced in SH-SY-5Y cells. However, both PGDHC and Pg-LPS contributed to the senescence of SH-SY5Y cells as indicated by the production of senescence-associated secretory phenotype (SASP) markers, including beta-galactosidase, cathepsin B (CtsB), and pro-inflammatory cytokines TNF-α, and IL-6. Additionally, PGDHC diminished expression of the senescence-protection marker sirtuin-1 in SH-SY-5Y cells.ConclusionsAltogether, our results indicate that P. gingivalis-derived PGDHC ceramide promotes amyloidogenesis and hyperphosphorylation, as well as the production of SASP factors. Thus, PGDHC may represent a novel class of bacterial-derived virulence factors for AD associated with periodontitis.

scholarly journals Characterization of Human Genes Modulated by Porphyromonas gingivalis Highlights the Ribosome, Hypothalamus, and Cholinergic Neurons

2021 ◽  
Vol 12 ◽  
Author(s):  
Sejal Patel ◽  
Derek Howard ◽  
Nityananda Chowdhury ◽  
Casey Derieux ◽  
Bridgette Wellslager ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Protein Targeting ◽  
Expression Patterns ◽  
Cholinergic Neurons ◽  
Functional Enrichment ◽  
Differentially Expressed ◽  
Human Genes ◽  
Lysine Residues

Porphyromonas gingivalis, a bacterium associated with periodontal disease, is a suspected cause of Alzheimer’s disease. This bacterium is reliant on gingipain proteases, which cleave host proteins after arginine and lysine residues. To characterize gingipain susceptibility, we performed enrichment analyses of arginine and lysine proportion proteome-wide. Genes differentially expressed in brain samples with detected P. gingivalis reads were also examined. Genes from these analyses were tested for functional enrichment and specific neuroanatomical expression patterns. Proteins in the SRP-dependent cotranslational protein targeting to membrane pathway were enriched for these residues and previously associated with periodontal and Alzheimer’s disease. These ribosomal genes are up-regulated in prefrontal cortex samples with detected P. gingivalis sequences. Other differentially expressed genes have been previously associated with dementia (ITM2B, MAPT, ZNF267, and DHX37). For an anatomical perspective, we characterized the expression of the P. gingivalis associated genes in the mouse and human brain. This analysis highlighted the hypothalamus, cholinergic neurons, and the basal forebrain. Our results suggest markers of neural P. gingivalis infection and link the cholinergic and gingipain hypotheses of Alzheimer’s disease.

scholarly journals Alzheimer’s Disease-Like Pathology Triggered by Porphyromonas gingivalis in Wild Type Rats Is Serotype Dependent

2020 ◽  
Vol 11 ◽  
Author(s):  
Jaime Díaz-Zúñiga ◽  
Jamileth More ◽  
Samanta Melgar-Rodríguez ◽  
Matías Jiménez-Unión ◽  
Francisca Villalobos-Orchard ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Wild Type

scholarly journals Can Porphyromonas gingivalis Contribute to Alzheimer’s Disease Already at the Stage of Gingivitis?

2021 ◽  
pp. 1-5
Author(s):  
Ingar Olsen
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Blood Stream ◽  
Brain Inflammation ◽  
Periodontal Pathogens ◽  
M1 Phase ◽  
Supragingival Plaque ◽  
The Brain

Alzheimer’s disease (AD) has been associated with periodontitis, which starts as gingivitis. Similar to periodontitis, gingivitis bacteria, bacterial products, and inflammatory mediators can travel to the brain via the blood stream and promote brain inflammation. Periodontal pathogens such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, both associated with AD, have been found in dental plaque of children already at the age of 3. It is suggested that these bacteria during long-term exposure may drive microglia (brain resident macrophage cells) into a pro-inflammatory M1 phase where they contribute to AD rather than protect against it. This notion comes from studies in mice showing that microglia actually can “remember” previous inflammatory challenge and become “trained” or “tolerant” to toxins like lipopolysaccharide. If gingivitis has an impact on AD, which should be verified, AD prophylaxis should start already at this pre-periodontitis stage with removal of supragingival plaque.

scholarly journals Porphyromonas gingivalis is a Strong Risk Factor for Alzheimer’s Disease

2020 ◽  
Vol 4 (1) ◽  
pp. 501-511
Author(s):  
Shalini Kanagasingam ◽  
Sasanka S. Chukkapalli ◽  
Richard Welbury ◽  
Sim K. Singhrao
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Bacterial Load ◽  
Amyloid Β ◽  
Wild Type Mouse ◽  
Paired Helical Filaments ◽  
Binding Domains ◽  
Flanking Regions

Porphyromonas gingivalis (P. gingivalis) is one of the several important bacterial pathogens associated with the sporadic Alzheimer’s disease (AD). Different serotypes are either capsulated or are non-capsulated. It has been demonstrated that P. gingivalis (non-capsulated) can reproduce the neurodegenerative AD-like changes in vitro, and a capsular P. gingivalis (strain W83) could reproduce the cardinal hallmark lesions of AD in a wild-type mouse model. All P. gingivalis forms express proteolytically active proteases that enable cleavage of the amyloid-β protin precursor (AβPP) and tau resulting in the formation of amyloid-β and neurofibrillary tangles. Tau is an established substrate for gingipains, which can cleave tau into various peptides. Some of the P. gingivalis fragmented tau protein peptides contain “VQIINK” and “VQIVYK” hexapeptide motifs which map to the flanking regions of the microtubule binding domains and are also found in paired helical filaments that form NFTs. P. gingivalis can induce peripheral inflammation in periodontitis and can also initiate signaling pathways that activate kinases, which in turn, phosphorylate neuronal tau. Periodontal disease related inflammation has metabolic implications for an individual’s peripheral and brain health as patients suffering from generalized periodontitis often have related co-morbidities and are “at risk” of developing AD. The aim here is to discuss the role of P. gingivalis behind such associations with the backdrop of huge efforts to test P. gingivalis virulence factors clinically (GAIN Trial: Phase 2/3 Study of COR388 in Subjects with AD) with inhibitors, which may lead to an intervention by reducing the pathogenic bacterial load.

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