Characteristics of the Salivary Microbiota in Periodontal Diseases and Potential Roles of Individual Bacterial Species To Predict the Severity of Periodontal Disease.

The purposes of this study were to examine the compositional changes in the salivary microbiota according to the severity of periodontal disease and to verify whether the distribution of specific bacterial species in saliva can distinguish the severity of disease. Saliva samples were collected from 8 periodontally healthy controls, 16 patients with gingivitis, 19 patients with moderate periodontitis, and 29 patients with severe periodontitis. The V3 and V4 regions of the 16S rRNA gene in the samples were sequenced, and the levels of 9 bacterial species showing significant differences among the groups by sequencing analysis were identified using quantitative real-time PCR (qPCR). The predictive performance of each bacterial species in distinguishing the severity of disease was evaluated using a receiver operating characteristic curve. Twenty-nine species, including Porphyromonas gingivalis, increased as the severity of disease increased, whereas 6 species, including Rothia denticola, decreased. The relative abundances of P. gingivalis, Tannerella forsythia, Filifactor alocis, and Prevotella intermedia determined by qPCR were significantly different among the groups. The three bacterial species P. gingivalis, T. forsythia, and F. alocis were positively correlated with the sum of the full-mouth probing depth and were moderately accurate at distinguishing the severity of periodontal disease. In conclusion, the salivary microbiota showed gradual compositional changes according to the severity of periodontitis, and the levels of P. gingivalis, T. forsythia, and F. alocis in mouth rinse saliva had the ability to distinguish the severity of periodontal disease. IMPORTANCE Periodontal disease is one of the most widespread medical conditions and the leading cause of tooth loss, imposing high economic costs and an increasing burden worldwide as life expectancy increases. Changes in the subgingival bacterial community during the progression of periodontal disease can affect the entire oral ecosystem, and bacteria in saliva can reflect the degree of bacterial imbalance in the oral cavity. This study explored whether the specific bacterial species in saliva can distinguish the severity of periodontal disease by analyzing the salivary microbiota and suggested P. gingivalis, T. forsythia, and F. alocis as biomarkers for distinguishing the severity of periodontal disease in saliva.

Polarization of human gingival fibroblasts by Th1-, Th2-, Th17-, and Treg-derived cytokines.

BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate whether gingival fibroblasts (GFs) can be differently activated and polarized into distinct functional subtypes by T-helper (Th) cytokines. METHODS: Gingival fibroblasts were stimulated with interferon (IFN)-γ, interleukin (IL)-4, IL-17, and transforming growth factor (TGF)-ß, representative cytokines of Th1, Th2, Th17, and regulatory T cells, respectively, and the gene expression profiles were analyzed by microarray. Differentially expressed genes (DEGs) in GFs stimulated by 4 cytokines were screened, and a gene ontology (GO) analysis of the DEGs was conducted. To confirm the reliability of the microarray results, the DEGs that showed the largest differences compared with non-stimulated GFs were further analyzed by RT-PCR. To evaluate the effect of polarization on GFs responses to lipopolysaccharide (LPS), GFs stimulated by 4 cytokines were further stimulated with Escherichia coli LPS and mRNA levels of several genes were analyzed using RT-PCR. RESULTS: Differentially expressed genes by 4 Th cytokines were enriched in different GO terms, and the patterns of gene expression on GFs were shown functionally different. GFs stimulated with IFN-γ (GF(IFN-γ)) up-regulated the expression of chemokines (chemokine (C-X-C motif) ligand (CXCL)9, -10, -11, chemokine (C-C motif) ligand (CCL)8), molecules involved in antigen presentation, complement component 3 (C3), and other immune response-related molecules, whereas they down-regulated the expression of several types of collagen, extracellular matrix (ECM) components, and DNA replication and nuclear protein-related molecules. By contrast, GF(IL-4) up-regulated the expression of ECM components, cell adhesion molecules, and tissue development-related molecules and down-regulated the expression of chemokines (CXCL10 and CXCL8) and adaptive immune response-related molecules. GF(IL-17) up-regulated the expression of chemokines and other molecules for neutrophil infiltration and activation, the pro-inflammatory cytokine IL-6, and C3. GF(TGF-ß) up-regulated the expression of cell growth-related molecules, ECM components, several types of collagen, and cell adhesion molecules and down-regulated the expression of molecules related to complement activation and bacterial recognition. GFs stimulated by 4 cytokines responded differently to LPS. CONCLUSION: These results show that Th cytokines can polarize GFs into cells with functionally distinct features: immune-activating but tissue-destructive GF(IFN-γ), tissue-reparative, and immune-inhibiting GF(IL-4), highly pro-inflammatory GF(IL-17), and potent tissue-reparative GF(TGF-ß).

IFN-γ or IL-4 polarization impacts the response of gingival fibroblasts to oral bacteria.

BACKGROUND AND OBJECTIVE: We previously reported that gingival fibroblasts (GFs) can be polarized into functionally distinct subtypes, immune-activating but tissue-destructive or tissue-reparative, in response to T helper (Th1) and Th2 stimuli, respectively. The purpose of this study was to evaluate the effect of polarization on GFs responses to oral bacteria. METHODS: Unprimed (GF(-)) and IFN-γ (GF(IFN-γ)) or IL-4 primed (GF(IL-4)) GFs were stimulated with live Fusobacterium nucleatum or Porphyromonas gingivalis. The mRNA expression of IL-1ß, IL-4, LPS-recognizing components (Toll-like receptor (TLR) 4, CD14), molecules involved in antigen presentation (human leukocyte antigen (HLA)-ABC, HLA-DP, CD74, CD40), chemokines (C-X-C motif chemokine (CXCL)10, CXCL11, chemokine (C-C motif) ligand 20 (CCL20)), collagen type 1 alpha 1 (COL1A1), and matrix metalloproteinase (MMP)-1, and the protein levels of IL-1ß, CD14, CXCL11, CCL20, and COL1A1 accumulated in supernatants were analyzed using real-time PCR and ELISA. RESULTS: In response to oral bacteria, the GF(IFN-γ) significantly upregulated the expression of LPS-recognizing components, molecules involved in antigen presentation, CXCL10, and CXCL11, whereas the levels of IL-4 and COL1A1 were downregulated, compared with GF(-). The levels of IL-1ß, CCL20, and MMP-1 from GF(IFN-γ) were differently regulated between both bacteria; F. nucleatum was synergistically upregulated, but P. gingivalis was downregulated. The GF(IL-4) stimulated with both bacteria upregulated the levels of IL-4, whereas the levels of TLR4 and chemokines were downregulated, compared with GF(-). The regulation of IL-1ß, CD14, CXCL11, CCL20, and COL1A1 proteins showed a similar tendency with mRNA regulation. CONCLUSION: Polarization of GFs with IFN-γ or IL-4 affected the way that GFs responded to oral bacteria through up or downregulation of inflammatory responses and extracellular matrix control.

BAIBA Attenuates the Expression of Inflammatory Cytokines and Attachment Molecules and ER Stress in HUVECs and THP-1 Cells.

OBJECTIVE: ß-Aminoisobutyric acid (BAIBA), a myokine, is a thymine catabolite that is induced during exercise, leading to browning of white fat, hepatic fatty acid oxidation, and suppression of hepatic lipogenesis. However, the effects of BAIBA on the progression of atherosclerosis remain unclear. METHODS: We performed a Western blot analyses to determine various protein expression. ELISAs (enzyme-linked immunosorbent assays), cell adhesion assays, and cell viability assays were also performed on human umbilical vascular endothelial cells (HUVECs) and human monocytes (THP-1 cells). RESULTS: In the current study, we demonstrate that BAIBA suppresses atherosclerotic reactions caused by lipopolysaccharide (LPS) treatment via an AMPK-dependent pathway. Treatment of HUVECs and THP-1 cells with BAIBA inhibited the LPS-induced phosphorylation of nuclear factor-κB (NFκB) and the secretion of proinflammatory cytokines. In HUVECs, expression of adhesion molecules and LPS-stimulated adhesion of THP-1 cells to the endothelium were significantly decreased after BAIBA treatment. Furthermore, LPS-induced endoplasmic reticulum (ER) stress and cell toxicity were significantly decreased after BAIBA treatment of HUVECs. Notably, all of these proatherosclerotic effects were fully abrogated by treatment with small interfering RNA targeting AMPK. CONCLUSION: BAIBA ameliorates LPS-induced atherosclerotic reactions via AMPK-mediated suppression of inflammation and ER stress.

Use of Self-Assembling Peptides to Enhance Stem Cell Function for Therapeutic Angiogenesis.

The use of nanomaterials for biomedical applications has become a promising field in regenerative medicine. Self-assembling peptides (SAPs) have been proposed as a good candidate because they are able to self-assemble into stable hydrogels and interact with cells or molecules when combined together. This in turn can lead to the improved survival or action of cells or molecules to obtain the desired effects. In this study, we investigated whether the combination of mesenchymal stem cells (MSCs) with SAPs could improve angiogenesis in ischemic hindlimbs of rats compared to MSC or SAP treatment alone. The combination of MSCs and SAPs showed an overall higher expression of angiogenesis markers on fluorescent immunohistochemical analysis and a lower degree of fibrosis and cell apoptosis, which in turn led to an overall tendency for improved perfusion of the ischemic hindlimbs. Finally, SAPs also showed the ability to recruit endogenous host MSCs into the site of action, especially when modified to incorporate substance P as a functional motif, which when injected with exogenous MSCs, allowed for the dual presence of MSCs at the site of action. Overall, these results suggest that SAPs can be applied with stem cells to potentiate angiogenesis, with potential therapeutic application in vascular diseases.

Maresin 1 attenuates pro-inflammatory reactions and ER stress in HUVECs via PPARα-mediated pathway.

The current study was designed to investigate the therapeutic effects of Maresin 1 (MAR1) on atherosclerotic response. Human monocytes THP-1 and human umbilical vein endothelial cells (HUVECs) were used to investigate the effects of MAR1 on lipopolysaccharide (LPS)-induced inflammation and apoptosis. In this study, we found that MAR1 induces peroxisome proliferator-activated receptor alpha (PPARα) expression. We also demonstrated that MAR1 suppresses atherosclerotic reactions caused by LPS treatment via a PPARα-dependent pathway. MAR1 treatment inhibited LPS-induced phosphorylation of nuclear factor kappa B (NF-κB) and secretion of pro-inflammatory cytokines in HUVECs and THP-1 cells. In HUVEC cells, expression of adhesion molecules and LPS-stimulated adhesion of THP-1 cells to the endothelium were significantly decreased after MAR1 treatment. Furthermore, LPS-induced endoplasmic reticulum (ER) stress and cell apoptosis was significantly decreased after MAR1 treatment of HUVECs. MAR1 also led to a dose-dependent increase in oxygen-regulated protein 150 (ORP150) expression which is responsible for the inhibition of ER stress. Notably, all of the pro-atherosclerotic effects were completely abrogated by treatment with small interfering (si) RNA targeting PPARα. In conclusion, MAR1 ameliorates LPS-induced atherosclerotic reactions via PPARα-mediated suppression of inflammation and ER stress.

Fibronectin Type III Domain Containing 4 attenuates hyperlipidemia-induced insulin resistance via suppression of inflammation and ER stress through HO-1 expression in adipocytes.

Although Fibronectin Type III Domain Containing 4 (FNDC4) has been reported to be involved in the modulation of inflammation in macrophages, its effects on inflammation and insulin resistance in adipose tissue are unknown. In the current study, we investigated the effects of FNDC4 on hyperlipidemia-mediated endoplasmic reticulum (ER) stress, inflammation, and insulin resistance in adipocytes via the AMP-activated protein kinase (AMPK)/heme oxygenase-1 (HO-1)-mediated pathway. Hyperlipidemia-induced nuclear factor κB (NFκB), inhibitory κBα (IκBα) phosphorylation, and pro-inflammatory cytokines such as TNFα and MCP-1 were markedly mitigated by FNDC4. Furthermore, FNDC4 treatment attenuated impaired insulin signaling in palmitate-treated differentiated 3T3-L1 cells and in subcutaneous adipose tissue of HFD-fed mice. FNDC4 administration ameliorated glucose intolerance and reduced HFD-induced body weight gain in mice. However, FNDC4 treatment did not affect calorie intake. Additionally, treatment with FNDC4 attenuated hyperlipidemia-induced phosphorylation or expression of ER stress markers such as IRE-1, eIF2α, and CHOP in 3T3-L1 adipocytes and in subcutaneous adipose tissue of mice. FNDC4 treatment stimulated AMPK phosphorylation and HO-1 expression in 3T3-L1 adipocytes and in subcutaneous adipose tissue of mice. siRNA-mediated suppression of AMPK and HO-1 abrogated the suppressive effects of FNDC4 on palmitate-induced ER stress, inflammation, and insulin resistance. In conclusion, our results show that FNDC4 ameliorates insulin resistance via AMPK/HO-1-mediated suppression of inflammation and ER stress, indicating that FNDC4 may be a novel therapeutic agent for treating insulin resistance and type 2 diabetes.

Chitinase-3-like protein 1 ameliorates atherosclerotic responses via PPARδ-mediated suppression of inflammation and ER stress.

Chitinase 3-like protein 1 (CHI3L1) is a novel biomarker of systemic inflammation. However, the effects of CHI3L1 on the progression of atherosclerosis remain to be explored. In the current study, we found that CHI3L1 induces peroxisome proliferator-activated receptor delta (PPARδ) expression, leading to a dose-dependent increase in oxygen-regulated protein 150 (ORP150) expression. We demonstrated that CHI3L1 suppresses atherosclerotic reactions caused by LPS treatment via a PPARδ-dependent pathway. Treatment of HUVECs and THP-1 cells with CHI3L1 suppressed LPS-induced phosphorylation of nuclear factor kappa B (NFκB) and secretion of proinflammatory cytokines such as TNFα and MCP-1. In HUVECs, expression of adhesion molecules and LPS-stimulated adhesion of THP-1 cells to the endothelium were significantly reduced after CHI3L1 treatment. Furthermore, LPS-induced endoplasmic reticulum (ER) stress and cell apoptosis were significantly ameliorated after treatment of HUVECs with CHI3L1. Particularly, all of the pro-atherosclerotic effects were significantly mitigated by treatment with small interfering (si) RNA for PPARδ. In conclusion, CHI3L1 ameliorates LPS-induced atherosclerotic reactions via PPARδ-mediated suppression of inflammation and ER stress.

ß-aminoisobutyric acid attenuates LPS-induced inflammation and insulin resistance in adipocytes through AMPK-mediated pathway.

BACKGROUND: ß-aminoisobutyric acid (BAIBA) is produced in skeletal muscle during exercise and has beneficial effects on obesity-related metabolic disorders such as diabetes and non-alcoholic fatty liver disease. Thus, it is supposed to prevent high fat diet (HFD)-induced inflammation and insulin resistance in adipose tissue though anti-inflammatory effects in obesity. Previous reports have also demonstrated strong anti-inflammatory effects of BAIBA. METHODS: We used BAIBA treated fully differentiated 3T3T-L1 mouse adipocytes to investigate the effects of exogenous BAIBA on inflammation and insulin signaling in adipocytes. Insulin signaling-mediated proteins and inflammation markers were measured by Western blot analysis. Secretion of pro-inflammatory cytokines were measured by ELISA. Lipid accumulation in differentiated 3 T3-L1 cells was stained by Oil red-O. Statistical analysis was performed by ANOVA and student's t test. RESULTS: BAIBA treatment suppressed adipogenesis assessed by adipogenic markers as well as lipid accumulation after full differentiation. We showed that BAIBA treatment stimulated AMP-activated protein kinase (AMPK) phosphorylation in a dose-dependent manner and lipopolysaccharide (LPS)-induced secretion of pro-inflammatory cytokines such as TNFα and MCP-1 was abrogated in BAIBA-treated 3 T3-L1 cells. Treatment of 3 T3-L1 cells with BAIBA reduced LPS-induced NFκB and IκB phosphorylation. Furthermore, BAIBA treatment ameliorated LPS-induced impairment of insulin signaling measured by IRS-1 and Akt phosphorylation and fatty acid oxidation. Suppression of AMPK by small interfering (si) RNA significantly restored these changes. CONCLUSIONS: We demonstrated anti-inflammatory and anti-insulin resistance effects of BAIBA in differentiated 3 T3-L1 cells treated with LPS through AMPK-dependent signaling. These results provide evidence for the beneficial effects of BAIBA not only in liver and skeletal muscle cells but also in adipose tissue.

CTRP9 Regulates Growth, Differentiation, and Apoptosis in Human Keratinocytes through TGFß1-p38-Dependent Pathway.

Impairment of wound healing is a common problem in individuals with diabetes. Adiponectin, an adipocyte-derived cytokine, has many beneficial effects on metabolic disorders such as diabetes, obesity, hypertension, and dyslipidemia. C1q/TNF-Related Protein 9 (CTRP9), the closest paralog of adiponectin, has been reported to have beneficial effects on wound healing. In the current study, we demonstrate that CTRP9 regulates growth, differentiation, and apoptosis of HaCaT human keratinocytes. We found that CTRP9 augmented expression of transforming growth factor beta 1 (TGFß1) by transcription factor activator protein 1 (AP-1) binding activity and phosphorylation of p38 in a dose-dependent manner. Furthermore, siRNA-mediated suppression of TGFß1 reversed the increase in p38 phosphorylation induced by CTRP9. siRNA-mediated suppression of TGFß1 or p38 significantly abrogated the effects of CTRP9 on cell proliferation and differentiation while inducing apoptosis, implying that CTRP9 stimulates wound recovery through a TGFß1-dependent pathway in keratinocytes. Furthermore, intravenous injection of CTRP9 via tail vein suppressed mRNA expression of Ki67 and involucrin whereas it augmented TGFß1 mRNA expression and caspase 3 activity in skin of type 1 diabetes animal models. In conclusion, our results suggest that CTRP9 has suppressive effects on hyperkeratosis, providing a potentially effective therapeutic strategy for diabetic wounds.

Recent Advances in the Development of Experimental Animal Models Mimicking Human Aortic Aneurysms.

Aortic aneurysm is a common and life-threatening disease that can cause death from rupture. Current therapeutic options are limited to surgical or endovascular procedures because no pharmacological approaches have been proven to decrease the chance of expansion or rupture. The best approach to the management of aortic aneurysm would be the understanding and prevention of the processes involved in disease occurrence, progression, and rupture. There is a need for animal models that can reproduce the pathophysiological features of human aortic aneurysm, and several such models have been studied. This review will emphasize recent advances in animal models used in the determination of mechanisms and treatments of aortic aneurysms.

Tracking the Fate of Muscle-derived Stem Cells: an Insight into the Distribution and Mode of Action.

PURPOSE: To examine the fate of muscle-derived stem cells (MDSC) after injection into different host conditions and provide an insight for their mechanism of action. MATERIALS AND METHODS: MDSCs differentiated in vitro towards the endothelial lineage and transfected with lentivirus tagged with green fluorescent protein (GFP) were injected into two animal models mimicking vascular diseases: hindlimb ischemia and carotid injury models. Injected cells were tracked at the site of injection and in remote organs by harvesting the respective tissues at different time intervals and performing immunofluorescent histological analyses. Stem cell survival was quantified at the site of injection for up to 4 weeks. RESULTS: MDSCs were successfully tagged with fluorescent material GFP and showed successful implantation into the respective injection sites. These cells showed a higher affinity to implant in blood vessel walls as shown by double fluorescent co-stain with CD31. Quantification of stem cell survival showed a timede pendent decrease from day 3 to 4 weeks (survival rate normalized against day 3 was 72.0% at 1 week, 26.8% at 2 weeks and 2.4% at 4 weeks). Stem cells were also found in distant organs, especially the kidneys and liver, which survived up to 4 weeks. CONCLUSION: MDSCs were successfully tracked in different vascular disease models, and their fate was assessed in terms of cell survival and distribution. Better understanding of the donor cell properties, including their interaction with the host conditions and their mechanism of action, are needed to enhance cell survival and achieve improved outcomes.

Modification of a rodent hindlimb model of secondary lymphedema: surgical radicality versus radiotherapeutic ablation.

Secondary lymphedema is an intractable disease mainly caused by damage of the lymphatic system during surgery, yet studies are limited by the lack of suitable animal models. The purpose of this study was to create an improved model of secondary lymphedema in the hindlimbs of rodents with sustained effects and able to mimic human lymphedema. This was achieved by combining previously reported surgical methods and radiation to induce chronic lymphedema. Despite more radical surgical destruction of superficial and deep lymphatic vessels, surgery alone was not enough to sustain increased hindlimb volume. Radiotherapy was necessary to prolong these effects, with decreased lymphatic flow on lymphoscintigraphy, but hindlimb necrosis occurred after 4 weeks due to radiation toxicity. The applicability of this model for studies of therapeutic lymphangiogenesis was subsequently tested by injecting muscle-derived stem cells previously cocultured with the supernatant of human lymphatic endothelial cells in vitro. There was a tendency for increased lymphatic flow which significantly increased lymphatic vessel formation after cell injection, but attenuation of hindlimb volume was not observed. These results suggest that further refinement of the rodent hindlimb model is needed by titration of adequate radiation dosage, while stem cell lymphangiogenesis seems to be a promising approach.

Potential role of vascular smooth muscle cell-like progenitor cell therapy in the suppression of experimental abdominal aortic aneurysms.

Abdominal aortic aneurysms (AAA) are a growing problem worldwide, yet there is no known medical therapy. The pathogenesis involves degradation of the elastic lamina by two combined mechanisms: increased degradation of elastin by matrix metalloproteinases (MMP) and decreased formation of elastin due to apoptosis of vascular smooth muscle cells (VSMC). In this study, we set out to examine the potential role of stem cells in the attenuation of AAA formation by inhibition of these pathogenetic mechanisms. Muscle-derived stem cells from murine skeletal muscles were isolated and stimulated with PDGF-BB in vitro for differentiation to VSMC-like progenitor cells (VSMC-PC). These cells were implanted in to elastase-induced AAAs in rats. The cell therapy group had decreased rate of aneurysm formation compared to control, and MMP expression at the genetic, protein and enzymatic level were also significantly decreased. Furthermore, direct implantation of VSMC-PCs in the intima of harvested aortas was visualized under immunofluorescent staining, suggesting that these cells were responsible for the inhibition of MMPs and consequent attenuation of AAA formation. These results show a promising role of stem cell therapy for the treatment of AAAs, and with further studies, may be able to reach clinical significance.

Muscle-derived stem cells promote angiogenesis and attenuate intimal hyperplasia in different murine vascular disease models.

Muscle-derived stem cells (MDSCs) are known to promote angiogenesis, but have never been studied in vascular diseases. We differentiated MDSCs into endothelial lineage cells in vitro by stimulation with shear stress and vascular endothelial growth factor. Such differentiated MDSCs (diff-MDSC) showed strong angiogenic potential in vitro. When tested in ischemic hindlimbs of mice, diff-MDSCs increased perfusion and decreased necrosis of the ischemic limbs, by promoting new vessel formation and by upregulating genes involved in endothelial expression. Such effects were not observed with native MDSCs (without endothelial stimulation in vitro). Diff-MDSCs were also injected into carotid arteries of rats after balloon denudation of the intima layer to induce intimal hyperplasia. The cell-treated group had significantly reduced intima-to-media thickness ratio compared to control, thus attenuating intimal hyperplasia by early re-endothelialization of the intima layer. Our findings suggest that MDSCs are a potential source of stem cell therapy for treatment of various vascular diseases, by inducing angiogenesis to improve perfusion in sites of ischemia, and by preventing intimal hyperplasia in sites of vessel injury.