Porphyromonas gingivalis and its lipopolysaccharide differently modulate epidermal growth factor-dependent signaling in human gingival epithelial cells

RNA Sequencing Reveals the Upregulation of FOXO Signaling Pathway in Porphyromonas gingivalis Persister-Treated Human Gingival Epithelial Cells

Porphyromonas gingivalis as the keystone periodontopathogen plays a critical role in the pathogenesis of periodontitis, and crucially accounts for inflammatory comorbidities such as cardiovascular disease and Alzheimer's disease. We recently identified the existence of P. gingivalis persisters and revealed the unforeseen perturbation of innate response in human gingival epithelial cells (HGECs) due to these noxious persisters. Herein, RNA sequencing revealed how P. gingivalis persisters affected the expression profile of cytokine genes and related signaling pathways in HGECs. Results showed that metronidazole-treated P. gingivalis persisters (M-PgPs) impaired the innate host defense of HGECs, in a similar fashion to P. gingivalis. Notably, over one thousand differentially expressed genes were identified in HGECs treated with M-PgPs or P. gingivalis with reference to the controls. Gene Ontology and KEGG pathway analysis demonstrated significantly enriched signaling pathways, such as FOXO. Importantly, the FOXO1 inhibitor rescued the M-PgP-induced disruption of cytokine expression. This study suggests that P. gingivalis persisters may perturb innate host defense, through the upregulation of the FOXO signaling pathway. Thus, the current findings could contribute to developing new approaches to tackling P. gingivalis persisters for the effective control of periodontitis and P. gingivalis-related inflammatory comorbidities.

The Effects of Rice Husk Liquid Smoke in Porphyromonas gingivalis-Induced Periodontitis

Objectives The purpose of this study was to analyze the effects of rice husk liquid smoke in Porphyromonas gingivalis -induced periodontitis in the inflammatory and proliferation marker such as nuclear factor kappa β (NF-kB), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), transforming growth factor-β (TGF-β), fibroblast growth factor 2 (FGF2), collagen type 1 (COL-1) expression, and the number of macrophages, lymphocytes, and fibroblasts.

Materials and Methods Rice husk liquid smoke is obtained by the pyrolysis process. Porphyromonas gingivalis -induced periodontitis in 20 μL phosphate-buffered saline containing 1 × 10 ⁹ CFU was injected into the lower anterior gingival sulcus of Wistar rats. The periodontitis was then treated with 20 μL/20 g body weight of rice husk liquid smoke once a day for 2 and 7 days, respectively. After treatment, the bone and lower anterior gingival sulcus were analyzed with immunohistochemistry and hematoxylin–eosin staining.

Results The treatment of periodontitis with rice husk liquid smoke showed a lower NF-kB, TNF-α, and IL-6 expression and a higher TGF-β, FGF2, and COL-1 expression than the control after treatment for 2 and 7 days ( p < 0.05), respectively. The number of macrophages and fibroblasts was also higher when compared with the control group ( p < 0.05), but the number of lymphocytes was lower than the control ( p < 0.05).

Conclusion Rice husk liquid smoke showed its effects on Porphyromonas gingivalis -induced periodontitis with a decrease in inflammatory markers and an increase in proliferation markers. The development of a rice husk liquid smoke periodontitis treatment is promising.

Bismuth drugs tackle Porphyromonas gingivalis and attune cytokine response in human cells

Periodontitis is the leading cause of severe tooth loss and edentulism in adults worldwide and is closely linked to systemic conditions such as diabetes and cardiovascular disease. Porphyromonas gingivalis is the key pathogen in periodontitis. Herein, we provided the first evidence that bismuth drugs suppress P. gingivalis in its planktonic, biofilm, and intracellular states. In total, 42 bismuth-associated proteins were identified including its major virulent factors (e.g., gingipains, hemagglutinin HagA, and fimbriae). Bismuth perturbed its iron acquisition, disturbed the energy metabolism and virulence, and deactivated multiple key enzymes (e.g., superoxide dismutase and thioredoxins). Moreover, bismuth inhibited its biofilm formation and disrupted the 3-day matured biofilms. Notably, the internalized P. gingivalis in various human cells (e.g., human gingival epithelium progenitors, HGEPs) was oppressed by bismuth but not the commonly used antibiotic metronidazole. Importantly, bismuth drugs enabled the counteraction of immuno-inflammatory responses in different host cells perturbed by P. gingivalis. The production of IL-6 and IL-8 attenuated by P. gingivalis in both of native and IL-1β-stimulated HGEPs was restored, while the bacterium-enhanced expression of IL-6, IL-1β, and TNFα in THP-1 macrophages was alleviated. This proof-of-concept study brings prospects for the potential reposition of the routinely used anti-Helicobacter pylori bismuth drugs to better manage inflammatory diseases such as periodontitis and P. gingivalis-related complex systemic disorders.

Metronidazole-Treated Porphyromonas gingivalis Persisters Invade Human Gingival Epithelial Cells and Perturb Innate Responses

Periodontitis as a biofilm-associated inflammatory disease is highly prevalent worldwide. It severely affects oral health and yet closely links to systemic diseases like diabetes and cardiovascular disease. Porphyromonas gingivalis as a "keystone" periodontopathogen drives the shift of microbe-host symbiosis to dysbiosis and critically contributes to the pathogenesis of periodontitis. Persisters represent a tiny subset of biofilm-associated microbes highly tolerant to lethal treatment of antimicrobials, and, notably, metronidazole-tolerant P. gingivalis persisters have recently been identified by our group. This study further explored the interactive profiles of metronidazole-treated P. gingivalis persisters (M-PgPs) with human gingival epithelial cells (HGECs). P. gingivalis cells (ATCC 33277) at stationary phase were treated with a lethal dosage of metronidazole (100 μg/ml, 6 h) for generating M-PgPs. The interaction of M-PgPs with HGECs was assessed by microscopy, flow cytometry, cytokine profiling, and quantitative PCR (qPCR). We demonstrated that the overall morphology and ultracellular structure of M-PgPs remained unchanged. Importantly, M-PgPs maintained the capabilities to adhere to and invade HGECs. Moreover, M-PgPs significantly suppressed proinflammatory cytokine expression in HGECs at a level comparable to that seen with the untreated P. gingivalis cells, through the thermosensitive components. The present report reveals that P. gingivalis persisters induced by lethal treatment of antibiotics were able to maintain their capabilities to adhere to and invade human gingival epithelial cells and to perturb the innate host responses. Novel strategies and approaches need to be developed for tackling P. gingivalis and favorably modulating the dysregulated immunoinflammatory responses for oral/periodontal health and general well-being.

Effect of scaling and root planing on level of immunoglobulin E and immunoglobulin G4 in children with gingivitis and house-dust mite allergy: A pilot randomised controlled trial

Background and Objective: There is a pressing need for developing innovative strategies to prevent allergic diseases among children. As house-dust mite (HDM) allergy is often seen in children with gingivitis, strategies should be derived from a conceptual framework of allergen elimination and pathogen eradication; one such strategy is dental scaling and root planing (SRP) to remove dental plaque and periodontal pathogens. The study aimed to evaluate the beneficial effects of comprehensive 6-months dental SRP to reduce the level of immunoglobulin E (IgE) and immunoglobulin G₄ (IgG₄) in children with gingivitis and HDM allergy. IgE and IgG₄, whose production is controlled mainly by Th-2 cells and B cells, are proven biomarkers for atopic inflammatory responses. Methods: The present study conducted a non-blinded randomised controlled trial with superiority design. A total of 10 subjects (age range 6-16 years) with gingivitis and positive skin-prick test to HDM from Pediatric Allergy Outpatient Clinic, Dr. Soetomo General Hospital were enrolled in the present study. Of the 10 subjects, only five received dental SRP. We further evaluated total serum IgE and IgG₄ level before and 6 months after treatment. Results and Discussion: Subjects in the standard treatment group showed a slight decrease in the IgE level ([Formula: see text]) but no change in the IgG₄ level ([Formula: see text]), while subjects in the intervention group showed a significant decrease in IgE ([Formula: see text]) and IgG₄ levels ([Formula: see text]). Conclusion: The study results suggest that 6-month comprehensive dental scaling combined with root planing may help to reduce IgE and IgG₄ levels in children with gingivitis and HDM allergy. Furthermore, untreated or undertreated gingivitis is often associated with worsening allergic manifestation and thus should be avoided. Trial Registration: ISRCTN31416107, retrospectively registered on 17 April 2018.

Gelatin nonwovens-based epithelial morphogenesis involves a signaling axis comprising EGF-receptor, MAP kinases ERK 1/2, and β1 integrin

In biomaterials research, biomechanics which support tissue regeneration steadily gains of importance. Hence, we have previously shown that gelatin-based electrospun nonwoven mats (NWMs) with a distinct modulus of elasticity (3.2 kPa) promotes epithelial morphogenesis. Since molecular mechanisms of this morphogenesis are still unknown, the present study aims at identifying molecules, involved herein. Epithelia established on the NMWs showed persistence of the activated state of the epidermal growth factor receptor (EGF-R), phosphorylated at the src-specific tyrosine 845 (EGF-R_T845 ) throughout the observation period of 10 days. To elucidate whether the observed morphogenesis mechanistically involves EGF-R signaling, we inhibited EGF-R, by employing the EGF-R_T845 specific inhibitor Gefitinib (IRESSA®). Gefitinib administration yielded a reduced expression of the β1 integrin subunit, a well-known cell-matrix interaction receptor, concomitant with downregulation of p42/44 ERK1/2 MAP-kinase activity. To elucidate whether the observed downregulation of β1 is EGF-R_T845 -dependent or emerging from ERK1/2 signaling, we exposed epithelia, grown on the NWMs, with the ERK1/2-directed inhibitor U0126. In the absence of Gefitinib, inhibition of p42/44 MAP-kinase activity resulted in decreased β1 integrin protein levels, thus indicating that β1 expression is dependent on ERK1/2 and not EGF-R_T845 . Our results showed the first time that an EGF-R-β1 integrin-signaling axis, including ERK1/2, promotes NWM-elasticity-based epithelial morphogenesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 663-677, 2019.