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Research on the negative impacts of PM 2.5 have been focused on lung, brain, immune, and metabolism-related diseases. However, little is known about the mechanism underlying the effects of PM 2.5 on the modulation of hematopoietic stem cell (HSC) fate. Maturation of the hematopoietic system and differentiation of hematopoietic stem progenitor cells (HSPCs) occurs soon after birth when infants are susceptible to external stresses. We investigated how exposure to atmospherically relevant artificial particulate matter of diameter < 2.5 µm (termed, PM 2.5 ) affects HSPCs in newborns. The lungs of newborn mice exposed to PM 2.5 exhibited higher levels of oxidative stress and inflammasome activation, which continued during aging. PM 2.5 also stimulated oxidative stress and inflammasome activation in bone marrow (BM). PM 2.5 -exposed infant mice at 12 months but not at 6 months displayed progressive senescence of HSCs accompanied by preferential impairment of the BM microenvironment with age-related phenotypes, as evidenced by colony-forming assay and serial transplantation and animal survival experiments. Further, PM 2.5 -exposed middle-aged mice did not exhibit radioprotective potential. Collectively, exposure of newborns to PM 2.5 causes progressive senescence of HSCs. These findings revealed a novel mechanism by which PM 2.5 affects the fate of HSCs, highlighting the crucial role of early life exposure to air pollution in determining human health outcomes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Scaffolds combined with bioactive agents can enhance bone regeneration at therapeutic sites. We explore whether combined supplementation with coumaric acid and recombinant human-cartilage oligomeric matrix protein-angiopoietin 1 (rhCOMP-Ang1) is an ideal approach for bone tissue engineering. We developed coumaric acid-conjugated absorbable collagen scaffold (CA-ACS) and investigated whether implanting CA-ACS in combination with rhCOMP-Ang1 facilitates ACS- or CA-ACS-mediated bone formation using a rat model of critically sized mandible defects. We examined the mechanisms by which coumaric acid and rhCOMP-Ang1 regulate behaviors of human periodontal ligament fibroblasts (hPLFs). The CA-ACS exhibits greater anti-degradation and mechanical strength properties than does ACS alone. Implanting CA-ACS loaded with rhCOMP-Ang1 greatly enhances bone regeneration at the defect via the activation of angiogenic, osteogenic, and anti-osteoclastic responses compared with other rat groups implanted with an ACS alone or CA-ACS. Treatment with both rhCOMP-Ang1 and coumaric acid increases proliferation, mineralization, and migration of cultured hPLFs via activation of the Ang1/Tie2 signaling axis at a greater rate than treatment with either of them alone. Collectively, this study demonstrates that CA-ACS impregnated with rhCOMP-Ang1 enhances bone regeneration at therapeutic sites, and this enhancement is associated with a synergistic interaction between rhCOMP-Ang1-mediated angiogenesis and coumaric acid-related antioxidant responses., (Copyright © 2022. Published by Elsevier B.V.)

Transgenic plant cell suspension culture systems have been utilized extensively as convenient and efficient expression systems for the production of recombinant human growth factors. We produced insulin-like growth factor-1 using a plant suspension culture system (p-IGF-1) and explored its effect on new bone formation in calvarial defects. We also compared the bone regenerating potential of p-IGF-1 with commercial IGF-1 derived from Escherichia coli (e-IGF-1). Male C57BL/6 mice underwent calvarial defect surgery, and the defects were loaded with absorbable collagen sponge (ACS) only (ACS group) or ACS impregnated with 13μg of p-IGF-1 (p-IGF-1 group) or e-IGF-1 (e-IGF-1 group). The sham group did not receive any treatment with ACS or IGFs after surgery. Live μCT and histological analyses showed critical-sized bone defects in the sham group, whereas greater bone formation was observed in the p-IGF-1 and e-IGF-1 groups than the ACS group both 5 and 10weeks after surgery. Bone mineral density, bone volume, and bone surface values were also higher in the IGF groups than in the ACS group. Local delivery of p-IGF-1 or e-IGF-1 more greatly enhanced the expression of osteoblast-specific markers, but inhibited osteoclast formation, in newly formed bone compared with ACS control group. Specifically, p-IGF-1 treatment induced higher expression of alkaline phosphatase, osteocalcin, and osteopontin in the defect site than did e-IGF-1. Furthermore, treatment with p-IGF-1, but not e-IGF-1, increased mineralization of MC3T3-E1 cells, with the attendant upregulation of osteogenic marker genes. Collectively, our findings suggest the potential of p-IGF-1 in promoting the processes required for bone regeneration., (Copyright © 2017. Published by Elsevier Ltd.)

Resveratrol is an antioxidant and anti-inflammatory polyphenol. Periodontitis is induced by oral pathogens, where a systemic inflammatory response accompanied by oxidative stress is the major event initiating disease. We investigated how resveratrol modulates cellular responses and the mechanisms related to this modulation in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (hGFs). We also explored whether resveratrol protects rats against alveolar bone loss in an experimental periodontitis model. Periodontitis was induced around the first upper molar of the rats by applying ligature infused with LPS. Stimulating hGFs with 5μg/ml LPS augmented the expression of cyclooxygenase-2, matrix metalloproteinase (MMP)-2, MMP-9, and Toll-like receptor-4. LPS treatment also stimulated the production of reactive oxygen species (ROS) and the phosphorylation of several protein kinases in the cells. However, the expression of heme oxygenase-1 (HO-1) and nuclear factor-E2 related factor 2 (Nrf2) was inhibited by the addition of LPS. Resveratrol treatment almost completely inhibited all of these changes in LPS-stimulated cells. Specifically, resveratrol alone augmented HO-1 induction via Nrf2-mediated signaling. Histological and micro-CT analyses revealed that administration of resveratrol (5mg/kg body weight) improved ligature/LPS-mediated alveolar bone loss in rats. Resveratrol also attenuated the production of inflammation-related proteins, the formation of osteoclasts, and the production of circulating ROS in periodontitis rats. Furthermore, resveratrol suppressed LPS-mediated decreases in HO-1 and Nrf2 levels in the inflamed periodontal tissues. Collectively, our findings suggest that resveratrol protects rats from periodontitic tissue damage by inhibiting inflammatory responses and by stimulating antioxidant defense systems., Statement of Significance: The aims of this study were to investigate how resveratrol modulates cellular responses and the mechanisms related to this modulation in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (hGFs) and protects rats against alveolar bone disruption in an experimental periodontitis model. Our findings suggest that resveratrol protects rats from periodontitic tissue damage by inhibiting inflammatory responses and by stimulating antioxidant defense systems. On the basis of our experiment studies, we proposed that resveratrol could be used as novel bioactive materials or therapeutic drug for the treatment of periodontitis or other inflammatory bone diseases like osteoporosis, arthritis etc. Furthermore, it could be also used for the modification or coating of implant materials as an antiinflammatory molecules which will help to accelerate bone formation. There are a few of reports suggesting antioxidant and anti-inflammatory potentials of resveratrol. However, our results highlight the cellular mechanisms by which resveratrol inhibits LPS-mediated cellular damages using human-originated gingival fibroblasts and also support the potential of resveratrol to suppress periodontitis-mediated tissue damages. We believe that the present findings might improve a clinical approach of using of resveratrol on human, although further detailed experiments will be needed., (Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Insulin like growth factor binding protein-3 (IGFBP-3) in bone cells and its utilization in dental implants have not been well studied. The aim of this study was to determine the osteogenic efficacy of chitosan gold nanoparticles (Ch-GNPs) conjugated with IGFBP-3 coated titanium (Ti) implants. Ch-GNPs were conjugated with IGFBP-3 plasmid DNA through a coacervation process. Conjugation was cast over Ti surfaces, and cells were seeded on coated surfaces. For in vitro analysis the expression of different proteins was analyzed by immunoblotting. For in vivo analysis, Ch-GNP/IGFBP-3 coated implants were installed in rat mandibles. Four weeks post-implantation, mandibles were examined by microcomputed tomography (μCT), immunohistochemistry, hematoxylin & eosin and tartrate resistance acid phosphatase staining. In vitro overexpressed Ch-GNP/IGFBP-3 coated Ti surfaces was associated with activation of extracellular signal related kinase (ERK), inhibition of the stress activated protein c-Jun N-terminal kinase (JNK) and enhanced bone morphogenetic protein (BMP)-2 and 7 compared to control. Further, in vivo, Ch-GNP/IGFBP-3 coated implants were associated with inhibition of implant induced osteoclastogenesis molecules, receptor activator of nuclear factor kappa-B ligand (RANKL) and enhanced expression of osteogenic molecules including BMP2/7 and osteopontin (OPN). The μCT analysis demonstrated that IGFBP-3 increased the volume of newly formed bone surrounding the implants compared to control (n=5; p<0.05). These results support the view that IGFBP-3 overexpression diminishes osteoclastogenesis and enhances osteogenesis of Ti implants, and can serve as a potent molecule for the development of good implantation., (Copyright © 2015. Published by Elsevier B.V.)

Introduction: The cytotoxicity of resin-based sealer is influential on the inflammatory reaction and cell survival for oral periapical cells. In this study, pachymic acid as an antioxidant was investigated for the improvement of bone disturbance against AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany)-induced inflammation in MC-3T3 E1 cells., Methods: AH Plus was prepared according to the manufacturer's instructions. Using mouse osteoblast cells (MC-3T3 E1), a specimen of AH Plus was eluted with the culture medium for 1 day and was diluted by 30%. The cellular cytotoxicity and reactive oxygen species formation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 2',7'-dichlorodihydrofluorescein diacetate with fluorescence-activated cell sorting. The secretion of proinflammatory cytokines was determined by an enzyme-linked immunosorbent assay, and the expression of inflammatory and osteogenic molecules was determined by immunoblotting., Results: Cells with AH Plus elutes showed a decrease of cell viability and ALP activity. However, pachymic acid and N-acetyl-L-cysteine (control antioxidant) restored cell viability and ALP activity damaged by AH plus. The secretion of nitric oxide, tumor necrosis factor α, and interleukin-1β were increased in AH Plus-stimulated MC-3T3 E1 cells, but pachymic acid suppressed its production. Furthermore, pachymic acid reduced the receptor activator of nuclear factor-κB ligand, cyclooxygenase-2, matrix metalloproteinase-2 and -9, increased bone morphogenetic protein-2 and -7, and runt-related transcription factor 2 despite AH Plus stimuli. In addition, pachymic acid affected the removal effect of reactive oxygen species formation as did N-acetyl-L-cysteine. More importantly, pachymic acid inhibited nuclear factor-κB translocation., Conclusions: The property of pachymic acid can mitigate the unfavorable conditions induced by AH Plus stimuli. Therefore, the use of pachymic acid is suggested to prevent the complications of oral diseases such as inflammation and alveolar destruction of the oral cavity., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Dental pulp functions include pulp cell activity involvement in dentin formation. In this study we investigated the age-related changes in dental pulp cells that may influence pulp cell activity for restoring pulp function., Methods: Human dental pulp cells (HDPCs) were serially subcultured until spontaneously arrested. Altered expression of chronic inflammatory molecules and age-related molecules were determined by Western blotting. Odontogenic functions impaired by senescence were assayed by Western blotting, reverse transcriptase polymerase chain reaction, alkaline phosphatase activity, and alizarin red S staining. To understand the mechanism of aging process by stress-induced premature senescence (SIPS), the cells were treated with H(2)O(2). Replicative senescence and SIPS were also compared., Results: Replicative senescence of HDPCs was characterized by senescence-associated β-galactosidase activity and reactive oxygen species formation. These cells exhibited altered expression of chronic inflammatory molecules such as intracellular adhesion molecule-1, vascular cell adhesion molecule-1, peroxisome proliferator activated receptor-gamma, and heme oxygenase-1 and age-related molecules such as p53, p21, phosphorylated-extracellular signal-regulated kinase, and c-myb. SIPS cell results were similar to replicative senescence. Furthermore, HDPCs decreased odontogenic markers such as dentin sialophosphoprotein and dentin matrix-1 and osteogenic markers such as bone morphogenetic protein-2 and -7, runt-related transcription factor-2, osteopontin, alkaline phosphatase activity, and mineralized nodule formation by replicative senescence and SIPS., Conclusions: This study suggests that development of aging-related molecules in pulp cells offers understanding of cellular mechanisms and biological events responsible for tooth preservation and maintenance strategies for healthy teeth across the life span., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Peroxisome proliferator-activated receptor gamma (PPARγ) has well-known anti-inflammatory action in human dental pulp cells (HDPCs). The purpose of this study was to investigate whether the anti-inflammatory action of PPARγ involves in cellular cytoprotection and supports odontoblast differentiation under oxidative stress in HDPCs., Methods: To simulate long-term oxidative stress, pulp cells were treated with 150 μmol hydrogen peroxide (H(2)O(2)) for 12 days. The replication deficiency adenovirus (adenovirus PPARγ) was introduced for PPARγ overexpression in pulp cells. The cellular cytotoxicity and reactive oxygen species formation by H(2)O(2) were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 2',7'-dichlorodihydrofluorescein diacetate with fluorescence-activated cell sorting assay. To determine the roles of PPARγ, several molecules of odontogenic/osteogenic and signal pathway were analyzed by reverse-transcription polymerase chain reaction and Western hybridization. Dentin mineralization was determined by alizarin red stain and alkaline phosphatase activity assay., Results: Pulp cells treated with long-term H(2)O(2) showed high reactive oxygen species formation, low cell viability, down-expression of antioxidant molecules (Cu/Zn and Mn superoxide dismutase), and odontogenic/osteogenic markers (eg, dentin sialophosphoprotein, dentin matrix protein-1, osteopontin, bone sialoprotein, Runx-2, and bone morphogenetic protein 2 and 7). In addition, pulp cells with oxidative stress underwent the activation of ERK1/2, activator protein-1, and nuclear factor-κB translocation to the nucleus. However, the PPARγ-overexpressed cells gave opposite results although under oxidative stress. Furthermore, PPARγ and its agonist rosiglitazone exhibited an induction of dentin mineralization under oxidative stress., Conclusions: PPARγ in pulp cells increases cell viability, odontoblastic differentiation, and dentin mineralization under oxidative stress. These results offer new insights into the potential antioxidative activity of PPARγ and its agonist for therapeutic agents for pulp vitality in HDPCs., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The cytotoxicity of AH26, a resin-based sealer, induces apoptosis in osteoblast cells. However, the apoptosis pathway is not completely understood. This study examined the apoptosis pathway and its regulation of AH26 through mitogen-activated protein kinase (MAPKs), which may play a role in reducing the cytotoxicity of AH26., Methods: Using mouse osteoblasts cells (MC-3T3-E1), specimens of AH26 were eluted with the culture medium for 1, 3, 5, and 7 days. The cytotoxicity was tested using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The induction of apoptosis was detected by Hoechst33258 staining and poly (ADP-ribose) polymerase (PARP) activation. The AH26-involved signal pathway was analyzed by immunoblotting with a specific antibody., Results: AH26 exhibited cytotoxicity toward MC-3T3-E1 cells, which resulted in mitochondria-mediated apoptosis, as confirmed by Bax expression and the displacement of cytochrome c from mitochondria to cytosol. As evidence of MAPKs activation, the cells treated with AH26 expressed stress-activated protein/c-jun N-terminal kinase (SAPK/JNK) and extracellular signal-regulated protein kinase (ERK1/2). SAPK/JNK activation appears to regulate apoptosis, whereas ERK activation protects cell survival., Conclusions: From these results, the toxicity of AH26 can be decreased by controlling the apoptosis signals. This approach might have potential applications for reducing the long-term stress of periapical tissue that improves endodontic treatment., (Copyright © 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)