Publications by authors named "Tetsuhiro Kajikawa"

20 Publications

  • Page 1 of 1

Mice lacking PLAP-1/asporin counteracts high fat diet-induced metabolic disorder and alveolar bone loss by controlling adipose tissue expansion.

Sci Rep 2021 Mar 2;11(1):4970. Epub 2021 Mar 2.

Department of Periodontology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.

Adipose tissue fibrosis with chronic inflammation is a hallmark of obesity-related metabolic disorders, and the role of proteoglycans in developing adipose tissue fibrosis is of interest. Periodontal disease is associated with obesity; however, the underlying molecular mechanisms remain unclear. Here we investigated the roles of periodontal ligament associated protein-1 (PLAP-1)/asporin, a proteoglycan preferentially and highly expressed in the periodontal ligament, in obesity-related adipose tissue dysfunction and adipocyte differentiation. It was found that PLAP-1 is also highly expressed in white adipose tissues. Plap-1 knock-out mice counteracted obesity and alveolar bone resorption induced by a high-fat diet. Plap-1 knock-down in 3T3-L1 cells resulted in less lipid accumulation, and recombinant PLAP-1 enhanced lipid accumulation in 3T3-L1 cells. In addition, it was found that primary preadipocytes isolated from Plap-1 knock-out mice showed lesser lipid accumulation than the wild-type (WT) mice. Furthermore, the stromal vascular fraction of Plap-1 knock-out mice showed different extracellular matrix gene expression patterns compared to WT. These findings demonstrate that PLAP-1 enhances adipogenesis and could be a key molecule in understanding the association between periodontal disease and obesity-related metabolic disorders.
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http://dx.doi.org/10.1038/s41598-021-84512-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7925592PMC
March 2021

The DEL-1/β3 integrin axis promotes regulatory T cell responses during inflammation resolution.

J Clin Invest 2020 12;130(12):6261-6277

Department of Basic and Translational Sciences, Laboratory of Innate Immunity and Inflammation, Penn Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

FOXP3+CD4+ regulatory T cells (Tregs) are critical for immune homeostasis and respond to local tissue cues, which control their stability and function. We explored here whether developmental endothelial locus-1 (DEL-1), which, like Tregs, increases during resolution of inflammation, promotes Treg responses. DEL-1 enhanced Treg numbers and function at barrier sites (oral and lung mucosa). The underlying mechanism was dissected using mice lacking DEL-1 or expressing a point mutant thereof, or mice with T cell-specific deletion of the transcription factor RUNX1, identified by RNA sequencing analysis of the DEL-1-induced Treg transcriptome. Specifically, through interaction with αvβ3 integrin, DEL-1 promoted induction of RUNX1-dependent FOXP3 expression and conferred stability of FOXP3 expression upon Treg restimulation in the absence of exogenous TGF-β1. Consistently, DEL-1 enhanced the demethylation of the Treg-specific demethylated region (TSDR) in the mouse Foxp3 gene and the suppressive function of sorted induced Tregs. Similarly, DEL-1 increased RUNX1 and FOXP3 expression in human conventional T cells, promoting their conversion into induced Tregs with increased TSDR demethylation, enhanced stability, and suppressive activity. We thus uncovered a DEL-1/αvβ3/RUNX1 axis that promotes Treg responses at barrier sites and offers therapeutic options for modulating inflammatory/autoimmune disorders.
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http://dx.doi.org/10.1172/JCI137530DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685741PMC
December 2020

An injectable hydrogel-formulated inhibitor of prolyl-4-hydroxylase promotes T regulatory cell recruitment and enhances alveolar bone regeneration during resolution of experimental periodontitis.

FASEB J 2020 10 19;34(10):13726-13740. Epub 2020 Aug 19.

Laboratory of Innate Immunity and Inflammation, Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.

The hypoxia-inducible factor 1α (HIF-1α) is critically involved in tissue regeneration. Hence, the pharmacological prevention of HIF-1α degradation by prolyl hydroxylase (PHD) under normoxic conditions is emerging as a promising option in regenerative medicine. Using a mouse model of ligature-induced periodontitis and resolution, we tested the ability of an injectable hydrogel-formulated PHD inhibitor, 1,4-dihydrophenonthrolin-4-one-3-carboxylic acid (1,4-DPCA/hydrogel), to promote regeneration of alveolar bone lost owing to experimental periodontitis. Mice injected subcutaneously with 1,4-DPCA/hydrogel at the onset of periodontitis resolution displayed significantly increased gingival HIF-1α protein levels and bone regeneration, as compared to mice treated with vehicle control. The 1,4-DPCA/hydrogel-induced increase in bone regeneration was associated with elevated expression of osteogenic genes, decreased expression of pro-inflammatory cytokine genes, and increased abundance of FOXP3 T regulatory (Treg) cells in the periodontal tissue. The enhancing effect of 1,4-DPCA/hydrogel on Treg cell accumulation and bone regeneration was reversed by AMD3100, an antagonist of the chemokine receptor CXCR4 that mediates Treg cell recruitment. In conclusion, the administration of 1,4-DPCA/hydrogel at the onset of periodontitis resolution promotes CXCR4-dependent accumulation of Treg cells and alveolar bone regeneration, suggesting a novel approach for regaining bone lost due to periodontitis.
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http://dx.doi.org/10.1096/fj.202001248RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7722135PMC
October 2020

Frontline Science: Activation of metabolic nuclear receptors restores periodontal tissue homeostasis in mice with leukocyte adhesion deficiency-1.

J Leukoc Biol 2020 11 18;108(5):1501-1514. Epub 2020 May 18.

School of Dental Medicine, Department of Basic and Translational Sciences, Laboratory of Innate Immunity and Inflammation, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

β2 Integrins mediate neutrophil-endothelial adhesion and recruitment of neutrophils to sites of inflammation. The diminished expression of β2 integrins in patients with mutations in the ITGB2 (CD18) gene (leukocyte adhesion deficiency-Type 1; LAD1) results in few or no neutrophils in peripheral tissues. In the periodontium, neutrophil paucity is associated with up-regulation of IL-23 and IL-17, which drive inflammatory bone loss. Using a relevant mouse model, we investigated whether diminished efferocytosis (owing to neutrophil scarcity) is associated with LAD1 periodontitis pathogenesis and aimed to develop approaches to restore the missing efferocytosis signals. We first showed that CD18 mice phenocopied human LAD1 in terms of IL-23/IL-17-driven inflammatory bone loss. Ab-mediated blockade of c-Mer tyrosine kinase (Mer), a major efferocytic receptor, mimicked LAD1-associated up-regulation of gingival IL-23 and IL-17 mRNA expression in wild-type (WT) mice. Consistently, soluble Mer-Fc reversed the inhibitory effect of efferocytosis on IL-23 expression in LPS-activated Mϕs. Adoptive transfer of WT neutrophils to CD18 mice down-regulated IL-23 and IL-17 expression to normal levels, but not when CD18 mice were treated with blocking anti-Mer Ab. Synthetic agonist-induced activation of liver X receptors (LXR) and peroxisome proliferator-activated receptors (PPAR), which link efferocytosis to generation of homeostatic signals, inhibited the expression of IL-23 and IL-17 and favorably affected the bone levels of CD18 mice. Therefore, our data link diminished efferocytosis-associated signaling due to impaired neutrophil recruitment to dysregulation of the IL-23-IL-17 axis and, moreover, suggest LXR and PPAR as potential therapeutic targets for treating LAD1 periodontitis.
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http://dx.doi.org/10.1002/JLB.5HI0420-648RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606738PMC
November 2020

The secreted protein DEL-1 activates a β3 integrin-FAK-ERK1/2-RUNX2 pathway and promotes osteogenic differentiation and bone regeneration.

J Biol Chem 2020 05 12;295(21):7261-7273. Epub 2020 Apr 12.

Department of Basic and Translational Sciences, Penn Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104. Electronic address:

The integrin-binding secreted protein developmental endothelial locus-1 (DEL-1) is involved in the regulation of both the initiation and resolution of inflammation in different diseases, including periodontitis, an oral disorder characterized by inflammatory bone loss. Here, using a mouse model of bone regeneration and cell-based mechanistic studies, we investigated whether and how DEL-1 can promote alveolar bone regeneration during resolution of experimental periodontitis. Compared with WT mice, mice lacking DEL-1 or expressing a DEL-1 variant with an Asp-to-Glu substitution in the RGD motif ("RGE point mutant"), which does not interact with RGD-dependent integrins, exhibited defective bone regeneration. Local administration of DEL-1 or of its N-terminal segment containing the integrin-binding RGD motif, but not of the RGE point mutant, reversed the defective bone regeneration in the DEL-1-deficient mice. Moreover, DEL-1 (but not the RGE point mutant) promoted osteogenic differentiation of MC3T3-E1 osteoprogenitor cells or of primary calvarial osteoblastic cells in a β3 integrin-dependent manner. The ability of DEL-1 to promote osteogenesis, indicated by induction of osteogenic genes such as the master transcription factor Runt-related transcription factor-2 () and by mineralized nodule formation, depended on its capacity to induce the phosphorylation of focal adhesion kinase (FAK) and of extracellular signal-regulated kinase 1/2 (ERK1/2). We conclude that DEL-1 can activate a β3 integrin-FAK-ERK1/2-RUNX2 pathway in osteoprogenitors and promote new bone formation in mice. These findings suggest that DEL-1 may be therapeutically exploited to restore bone lost due to periodontitis and perhaps other osteolytic conditions.
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http://dx.doi.org/10.1074/jbc.RA120.013024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247308PMC
May 2020

Pressure Cycling Technology Assisted Mass Spectrometric Quantification of Gingival Tissue Reveals Proteome Dynamics during the Initiation and Progression of Inflammatory Periodontal Disease.

Proteomics 2020 02 15;20(3-4):e1900253. Epub 2020 Jan 15.

Section of Peridontology and Dental Prevention, Division of Oral Diseases, Department of Dental Medicine, Kartolinska Insitutet, Alfred Nobels alle 8, 14104, Huddinge, Sweden.

Understanding the progression of periodontal tissue destruction is at the forefront of periodontal research. The authors aimed to capture the dynamics of gingival tissue proteome during the initiation and progression of experimental (ligature-induced) periodontitis in mice. Pressure cycling technology (PCT), a recently developed platform that uses ultra-high pressure to disrupt tissues, is utilized to achieve efficient and reproducible protein extraction from ultra-small amounts of gingival tissues in combination with liquid chromatography-tandem mass spectrometry (MS). The MS data are processed using Progenesis QI and the regulated proteins are subjected to METACORE, STRING, and WebGestalt for functional enrichment analysis. A total of 1614 proteins with ≥2 peptides are quantified with an estimated protein false discovery rate of 0.06%. Unsupervised clustering analysis shows that the gingival tissue protein abundance is mainly dependent on the periodontitis progression stage. Gene ontology enrichment analysis reveals an overrepresentation in innate immune regulation (e.g., neutrophil-mediated immunity and antimicrobial peptides), signal transduction (e.g., integrin signaling), and homeostasis processes (e.g., platelet activation and aggregation). In conclusion, a PCT-assisted label-free quantitative proteomics workflow that allowed cataloging the deepest gingival tissue proteome on a rapid timescale and provided novel mechanistic insights into host perturbation during periodontitis progression is applied.
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http://dx.doi.org/10.1002/pmic.201900253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7033018PMC
February 2020

Complement-Dependent Mechanisms and Interventions in Periodontal Disease.

Front Immunol 2019 12;10:406. Epub 2019 Mar 12.

Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.

Periodontitis is a prevalent inflammatory disease that leads to the destruction of the tooth-supporting tissues. Current therapies are not effective for all patients and this oral disease continues to be a significant public health and economic burden. Central to periodontal disease pathogenesis is a reciprocally reinforced interplay between microbial dysbiosis and destructive inflammation, suggesting the potential relevance of host-modulation therapies. This review summarizes and discusses clinical observations and pre-clinical intervention studies that collectively suggest that complement is hyperactivated in periodontitis and that its inhibition provides a therapeutic benefit. Specifically, interception of the complement cascade at its central component, C3, using a locally administered small peptidic compound (Cp40/AMY-101) protected non-human primates from induced or naturally occurring periodontitis. These studies indicate that C3-targeted intervention merits investigation as an adjunctive treatment of periodontal disease in humans.
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http://dx.doi.org/10.3389/fimmu.2019.00406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6422998PMC
September 2020

Macrophage β2-Integrins Regulate IL-22 by ILC3s and Protect from Lethal Citrobacter rodentium-Induced Colitis.

Cell Rep 2019 02;26(6):1614-1626.e5

Department of Microbiology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104, USA. Electronic address:

β2-integrins promote neutrophil recruitment to infected tissues and are crucial for host defense. Neutrophil recruitment is defective in leukocyte adhesion deficiency type-1 (LAD1), a condition caused by mutations in the CD18 (β2-integrin) gene. Using a model of Citrobacter rodentium (CR)-induced colitis, we show that CD18 mice display increased intestinal damage and systemic bacterial burden, compared to littermate controls, ultimately succumbing to infection. This phenotype is not attributed to defective neutrophil recruitment, as it is shared by CXCR2 mice that survive CR infection. CR-infected CD18 mice feature prominent upregulation of IL-17 and downregulation of IL-22. Exogenous IL-22 administration, but not endogenous IL-17 neutralization, protects CD18 mice from lethal colitis. β2-integrin expression on macrophages is mechanistically linked to Rac1/ROS-mediated induction of noncanonical-NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3) inflammasome-dependent IL-1β production, which promotes ILC3-derived IL-22. Therefore, β2-integrins are required for protective IL-1β-dependent IL-22 responses in colitis, and the identified mechanism may underlie the association of human LAD1 with colitis.
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http://dx.doi.org/10.1016/j.celrep.2019.01.054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404229PMC
February 2019

DEL-1 promotes macrophage efferocytosis and clearance of inflammation.

Nat Immunol 2019 01 19;20(1):40-49. Epub 2018 Nov 19.

Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany.

Resolution of inflammation is essential for tissue homeostasis and represents a promising approach to inflammatory disorders. Here we found that developmental endothelial locus-1 (DEL-1), a secreted protein that inhibits leukocyte-endothelial adhesion and inflammation initiation, also functions as a non-redundant downstream effector in inflammation clearance. In human and mouse periodontitis, waning of inflammation was correlated with DEL-1 upregulation, whereas resolution of experimental periodontitis failed in DEL-1 deficiency. This concept was mechanistically substantiated in acute monosodium-urate-crystal-induced inflammation, where the pro-resolution function of DEL-1 was attributed to effective apoptotic neutrophil clearance (efferocytosis). DEL-1-mediated efferocytosis induced liver X receptor-dependent macrophage reprogramming to a pro-resolving phenotype and was required for optimal production of at least certain specific pro-resolving mediators. Experiments in transgenic mice with cell-specific overexpression of DEL-1 linked its anti-leukocyte-recruitment action to endothelial cell-derived DEL-1 and its efferocytic/pro-resolving action to macrophage-derived DEL-1. Thus, the compartmentalized expression of DEL-1 facilitates distinct homeostatic functions in an appropriate context that can be harnessed therapeutically.
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http://dx.doi.org/10.1038/s41590-018-0249-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6291356PMC
January 2019

Fibroblast growth factor-2 inhibits CD40-mediated periodontal inflammation.

J Cell Physiol 2019 05 28;234(5):7149-7160. Epub 2018 Oct 28.

Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka, Japan.

Fibroblast growth factor-2 (FGF-2) stimulates periodontal regeneration by a broad spectrum of effects on periodontal ligament (PDL) cells, such as proliferation, migration, and production of extracellular matrix. A critical factor in the success of periodontal regeneration is the rapid resolution of inflammatory responses in the tissue. We explored an anti-inflammatory effect of FGF-2 during periodontal regeneration and healing. We found that FGF-2 on mouse periodontal ligament cells (MPDL22) markedly downregulated CD40 expression, a key player of inflammation. In addition, FGF-2 inhibited CD40 signaling by the non-canonical nuclear factor-kappa B2 (NFκB2) pathway, resulting in decreased production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), which have the potential to recruit immune cells to inflamed sites. Furthermore, in vivo treatment of FGF-2 enhanced healing of skin wounds by counteracting the CD40-mediated inflammation. These results reveal that FGF-2 has an important function as a negative regulator of inflammation during periodontal regeneration and healing.
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http://dx.doi.org/10.1002/jcp.27469DOI Listing
May 2019

A dysbiotic microbiome triggers T17 cells to mediate oral mucosal immunopathology in mice and humans.

Sci Transl Med 2018 10;10(463)

Oral Immunity and Inflammation Unit, NIDCR, NIH, Bethesda, MD 20892, USA.

Periodontitis is one of the most common human inflammatory diseases, yet the mechanisms that drive immunopathology and could be therapeutically targeted are not well defined. Here, we demonstrate an expansion of resident memory T helper 17 (T17) cells in human periodontitis. Phenocopying humans, T17 cells expanded in murine experimental periodontitis through local proliferation. Unlike homeostatic oral T17 cells, which accumulate in a commensal-independent and interleukin-6 (IL-6)-dependent manner, periodontitis-associated expansion of T17 cells was dependent on the local dysbiotic microbiome and required both IL-6 and IL-23. T17 cells and associated neutrophil accumulation were necessary for inflammatory tissue destruction in experimental periodontitis. Genetic or pharmacological inhibition of T17 cell differentiation conferred protection from immunopathology. Studies in a unique patient population with a genetic defect in T17 cell differentiation established human relevance for our murine experimental studies. In the oral cavity, human T17 cell defects were associated with diminished periodontal inflammation and bone loss, despite increased prevalence of recurrent oral fungal infections. Our study highlights distinct functions of T17 cells in oral immunity and inflammation and paves the way to a new targeted therapeutic approach for the treatment of periodontitis.
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http://dx.doi.org/10.1126/scitranslmed.aat0797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6330016PMC
October 2018

Safety profile after prolonged C3 inhibition.

Clin Immunol 2018 12 10;197:96-106. Epub 2018 Oct 10.

Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:

The central component of the complement cascade, C3, is involved in various biological functions, including opsonization of foreign bodies, clearance of waste material, activation of immune cells, and triggering of pathways controlling development. Given its broad role in immune responses, particularly in phagocytosis and the clearance of microbes, a deficiency in complement C3 in humans is often associated with multiple bacterial infections. Interestingly, an increased susceptibility to infections appears to occur mainly in the first two years of life and then wanes throughout adulthood. In view of the well-established connection between C3 deficiency and infections, therapeutic inhibition of complement at the level of C3 is often considered with caution or disregarded. We therefore set out to investigate the immune and biochemical profile of non-human primates under prolonged treatment with the C3 inhibitor compstatin (Cp40 analog). Cynomolgus monkeys were dosed subcutaneously with Cp40, resulting in systemic inhibition of C3, for 1 week, 2 weeks, or 3 months. Plasma concentrations of both C3 and Cp40 were measured periodically and complete saturation of plasma C3 was confirmed. No differences in hematological, biochemical, or immunological parameters were identified in the blood or tissues of animals treated with Cp40 when compared to those injected with vehicle alone. Further, skin wounds showed no signs of infection in those treated with Cp40. In fact, Cp40 treatment was associated with a trend toward accelerated wound healing when compared with the control group. In addition, a biodistribution study in a rhesus monkey indicated that the distribution of Cp40 in the body is associated with the presence of C3, concentrating in organs that accumulate blood and produce C3. Overall, our data suggest that systemic C3 inhibition in healthy adult non-human primates is not associated with a weakened immune system or susceptibility to infections.
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http://dx.doi.org/10.1016/j.clim.2018.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6258316PMC
December 2018

The purinergic receptor P2X5 contributes to bone loss in experimental periodontitis.

BMB Rep 2018 Sep;51(9):468-473

Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.

Purinergic receptor signaling is increasingly recognized as an important regulator of inflammation. The P2X family purinergic receptors P2X5 and P2X7 have both been implicated in bone biology, and it has been suggested recently that P2X5 may be a significant regulator of inflammatory bone loss. However, a role for P2X5 in periodontitis is unknown. The present study aimed to evaluate the functional role of P2X5 in ligatureinduced periodontitis in mice. Five days after placement of ligature, analysis of alveolar bone revealed decreased bone loss in P2rx5-/- mice compared to P2rx7-/- and WT control mice. Gene expression analysis of the gingival tissue of ligated mice showed that IL1b, IL6, IL17a and Tnfsf11 expression levels were significantly reduced in P2rx5-/- compared to WT mice. These results suggest the P2X5 receptor may regulate bone loss related to periodontitis and it may thus be a novel therapeutic target in this oral disease. [BMB Reports 2018; 51(9): 468-473].
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6177510PMC
September 2018

Safety and Efficacy of the Complement Inhibitor AMY-101 in a Natural Model of Periodontitis in Non-human Primates.

Mol Ther Methods Clin Dev 2017 Sep 18;6:207-215. Epub 2017 Aug 18.

University of Pennsylvania, School of Dental Medicine, Department of Microbiology, Philadelphia, PA 19104, USA.

Periodontitis is a chronic inflammatory disease associated with overactivation of the complement system. Recent preclinical studies suggest that host-modulation therapies may contribute to effective treatment of human periodontitis, which may lead to loss of teeth and function if untreated. We previously showed that locally administered AMY-101 (Cp40), a peptidic inhibitor of the central complement component C3, can inhibit naturally occurring periodontitis in non-human primates (NHPs) when given once a week. This study was undertaken to determine the local safety of increasing doses of the drug as well as its efficacy when given at a reduced frequency or after systemic administration. Our findings have determined a local dose of AMY-101 (0.1 mg/site) that is free of local irritation and effective when given once every 3 weeks. Moreover, a daily subcutaneous dose of AMY-101 (4 mg/kg bodyweight) was protective against NHP periodontitis, suggesting that patients treated for systemic disorders (e.g., paroxysmal nocturnal hemoglobinuria) can additionally benefit in terms of improved periodontal condition. In summary, AMY-101 appears to be a promising candidate drug for the adjunctive treatment of human periodontitis, a notion that merits investigation in human clinical trials.
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http://dx.doi.org/10.1016/j.omtm.2017.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577415PMC
September 2017

Secreted protein Del-1 regulates myelopoiesis in the hematopoietic stem cell niche.

J Clin Invest 2017 Oct 28;127(10):3624-3639. Epub 2017 Aug 28.

Department of Clinical Pathobiochemistry, Institute for Clinical Chemistry and Laboratory Medicine, and.

Hematopoietic stem cells (HSCs) remain mostly quiescent under steady-state conditions but switch to a proliferative state following hematopoietic stress, e.g., bone marrow (BM) injury, transplantation, or systemic infection and inflammation. The homeostatic balance between quiescence, self-renewal, and differentiation of HSCs is strongly dependent on their interactions with cells that constitute a specialized microanatomical environment in the BM known as the HSC niche. Here, we identified the secreted extracellular matrix protein Del-1 as a component and regulator of the HSC niche. Specifically, we found that Del-1 was expressed by several cellular components of the HSC niche, including arteriolar endothelial cells, CXCL12-abundant reticular (CAR) cells, and cells of the osteoblastic lineage. Del-1 promoted critical functions of the HSC niche, as it regulated long-term HSC (LT-HSC) proliferation and differentiation toward the myeloid lineage. Del-1 deficiency in mice resulted in reduced LT-HSC proliferation and infringed preferentially upon myelopoiesis under both steady-state and stressful conditions, such as hematopoietic cell transplantation and G-CSF- or inflammation-induced stress myelopoiesis. Del-1-induced HSC proliferation and myeloid lineage commitment were mediated by β3 integrin on hematopoietic progenitors. This hitherto unknown Del-1 function in the HSC niche represents a juxtacrine homeostatic adaptation of the hematopoietic system in stress myelopoiesis.
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http://dx.doi.org/10.1172/JCI92571DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617665PMC
October 2017

Milk fat globule epidermal growth factor 8 inhibits periodontitis in non-human primates and its gingival crevicular fluid levels can differentiate periodontal health from disease in humans.

J Clin Periodontol 2017 May 12;44(5):472-483. Epub 2017 Apr 12.

Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.

Aim: We have previously shown that the secreted glycoprotein milk fat globule epidermal growth factor 8 (MFG-E8) has anti-inflammatory and anti-osteoclastogenic properties. Our objective was to investigate the potential of MFG-E8 as a diagnostic or therapeutic agent in periodontitis.

Materials And Methods: Periodontitis was induced in non-human primates (NHPs) by placing ligatures around posterior teeth on both halves of the mandible for a split-mouth design: one side was treated with MFG-E8-Fc and the other with Fc control. Disease was assessed by clinical periodontal examinations, radiographic analysis of bone loss, and analysis of cytokine mRNA expression in gingival biopsy samples. Gingival crevicular fluid (GCF) was collected from human healthy volunteers or subjects with gingivitis, chronic moderate periodontitis, or chronic severe periodontitis. Additionally, GCF was collected from a subset of severe periodontitis patients following scaling and root planing (SRP) and after pocket reduction surgery. GCF was analysed to quantify MFG-E8 and periodontitis-relevant cytokines using multiplex assays.

Results: In NHPs, sites treated with MFG-E8-Fc exhibited significantly less ligature-induced periodontal inflammation and bone loss than Fc control-treated sites. In humans, the GCF levels of MFG-E8 were significantly higher in health than in periodontitis, whereas the reverse was true for the proinflammatory cytokines tested. Consistently, MFG-E8 was elevated in GCF after both non-surgical (SRP) and surgical periodontal treatment of periodontitis patients.

Conclusion: MFG-E8 is, in principle, a novel therapeutic agent and biomarker of periodontitis.
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http://dx.doi.org/10.1111/jcpe.12707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433891PMC
May 2017

Complement inhibition in pre-clinical models of periodontitis and prospects for clinical application.

Semin Immunol 2016 06 24;28(3):285-91. Epub 2016 Mar 24.

Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

Periodontitis is a dysbiotic inflammatory disease leading to the destruction of the tooth-supporting tissues. Current therapies are not always effective and this prevalent oral disease continues to be a significant health and economic burden. Early clinical studies have associated periodontitis with elevated complement activity. Consistently, subsequent genetic and pharmacological studies in rodents have implicated the central complement component C3 and downstream signaling pathways in periodontal host-microbe interactions that promote dysbiosis and inflammatory bone loss. This review discusses these mechanistic advances and moreover focuses on the compstatin family of C3 inhibitors as a novel approach to treat periodontitis. In this regard, local application of the current lead analog Cp40 was recently shown to block both inducible and naturally occurring periodontitis in non-human primates. These promising results from non-human primate studies and the parallel development of Cp40 for clinical use highlight the feasibility for developing an adjunctive, C3-targeted therapy for human periodontitis.
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http://dx.doi.org/10.1016/j.smim.2016.03.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4987193PMC
June 2016

Inhibition of pre-existing natural periodontitis in non-human primates by a locally administered peptide inhibitor of complement C3.

J Clin Periodontol 2016 Mar 3;43(3):238-49. Epub 2016 Mar 3.

Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.

Aim: Human periodontitis is associated with overactivation of complement, which is triggered by different mechanisms converging on C3, the central hub of the system. We assessed whether the C3 inhibitor Cp40 inhibits naturally occurring periodontitis in non-human primates (NHPs).

Materials And Methods: Non-human primates with chronic periodontitis were intra-gingivally injected with Cp40 either once (5 animals) or three times (10 animals) weekly for 6 weeks followed by a 6-week follow-up period. Clinical periodontal examinations and collection of gingival crevicular fluid and biopsies of gingiva and bone were performed at baseline and during the study. A one-way repeated-measures anova was used for data analysis.

Results: Whether administered once or three times weekly, Cp40 caused a significant reduction in clinical indices that measure periodontal inflammation (gingival index and bleeding on probing), tissue destruction (probing pocket depth and clinical attachment level) or tooth mobility. These clinical changes were associated with significantly reduced levels of pro-inflammatory mediators and decreased numbers of osteoclasts in bone biopsies. The protective effects of Cp40 persisted, albeit at reduced efficacy, for at least 6 weeks following drug discontinuation.

Conclusion: Cp40 inhibits pre-existing chronic periodontal inflammation and osteoclastogenesis in NHPs, suggesting a novel adjunctive anti-inflammatory therapy for treating human periodontitis.
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http://dx.doi.org/10.1111/jcpe.12507DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4803614PMC
March 2016

Role of ferritin in the cytodifferentiation of periodontal ligament cells.

Biochem Biophys Res Commun 2012 Oct 11;426(4):643-8. Epub 2012 Sep 11.

Department of Periodontology, Peking University School and Hospital of Stomatology, 22 Zhongguancun Nandajie, Haidian District, Beijing 100081, PR China.

This study investigated the expression and functions of ferritin, which is involved in osteoblastogenesis, in the periodontal ligament (PDL). The PDL is one of the most important tissues for maintaining the homeostasis of teeth and tooth-supporting tissues. Real-time PCR analyses of the human PDL revealed abundant expression of ferritin light polypeptide (FTL) and ferritin heavy polypeptide (FTH), which encode the highly-conserved iron storage protein, ferritin. Immunohistochemical staining demonstrated predominant expression of FTL and FTH in mouse PDL tissues in vivo. In in vitro-maintained mouse PDL cells, FTL and FTH expressions were upregulated at both the mRNA and protein levels during the course of cytodifferentiation and mineralization. Interestingly, stimulation of PDL cells with exogenous apoferritin (iron-free ferritin) increased calcified nodule formation and alkaline phosphatase activity as well as the mRNA expressions of mineralization-related genes during the course of cytodifferentiation. On the other hand, RNA interference of FTH inhibited the mineralized nodule formation of PDL cells. This is the first report to demonstrate that ferritin is predominantly expressed in PDL tissues and positively regulates the cytodifferentiation and mineralization of PDL cells.
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http://dx.doi.org/10.1016/j.bbrc.2012.09.008DOI Listing
October 2012

Basic fibroblast growth factor regulates expression of heparan sulfate in human periodontal ligament cells.

Matrix Biol 2008 Apr 26;27(3):232-41. Epub 2007 Oct 26.

Department of Periodontology, Division of Oral Biology and Disease Control, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.

Heparan sulfate (HS) proteoglycan is a widely distributed biological molecule that mediates a variety of physiological responses in development, cell growth, cell migration, and wound healing. We examined the effects of basic fibroblast growth factor-2 (FGF-2), which is known to modulate extracellular matrix (ECM) production of various cell types, on the production of HS proteoglycan by human periodontal ligament (HPDL) cells. We also examined the effects of FGF-2 on the expression of syndecans, a major family of membrane-bound HS proteoglycans. Treatment of HPDL cells with FGF-2 for 72 h resulted in a pronounced increase in the level of HS in the culture supernatant in a dose-dependent manner. However, reverse transcription-polymerase chain reaction data (RT-PCR) revealed that FGF-2 marginally reduced the gene expression of syndecan-1, -2, and -4, and did not alter the level of syndecan-3 mRNA. Furthermore, FGF-2 did not have an effect on the mRNA expression of enzymes associated with HS biosynthesis. Interestingly, FACS analysis revealed that the syndecan family displayed diverse alterations in response to FGF-2. FGF-2 barely altered the expression of syndecan-1, but decreased the expression of syndecan-2 and -4 on HPDL cells. Moreover, dot blot analysis showed that FGF-2 did not alter the level of syndecan-1 and -2, but enhanced the level of syndecan-4 in culture supernatants of FGF-2-stimulated HPDL cells. These results suggest that the FGF-2-activated increase in the level of HS in conditioned medium may be a result of shedding of syndecan-4 from the HPDL cell surface. Taken together, FGF-2 may differentially regulate the expression of HS proteoglycans in a HS-proteoglycan-subtype-dependent manner. The diversity of the expression patterns of HS proteoglycans may be associated with the FGF-2-induced biological functions of HPDL cells.
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http://dx.doi.org/10.1016/j.matbio.2007.10.005DOI Listing
April 2008