Fusanori Nishimura

Comparative Study of the Chemotactic Responses of Periodontal Ligament Cells and Gingival Fibroblasts to Polypeptide Growth Factors

Selective recruitment of periodontal ligament cells to a previously exposed root surface is believed to enhance periodontal regeneration. It has been hypothesized that competition from gingival fibroblasts may reduce the potential of periodontal regeneration. We compared the migratory responses of PDL cells and gingival fibroblasts to a variety of biologicals. Parallel experiments designed to examine the directed migration responses of both periodontal ligament cells (PDL cells) and gingival fibroblasts (GF) isolated from the same donors were conducted using Platelet Derived Growth Factor (PDGF), Insulin Like Growth Factor-I, -II (IGF-I, -II), Epidermal Growth Factor (EGF), Transforming Growth Factor-β (TGF-β), and the chemotactic factor derived from the conditioned culture media of PDL cells (termed PDL-CTX) as attractants. Both PDL cells and GF exhibited dose-dependent migratory responses when challenged with PDGF, IGF-I, IGF-II, EGF, and TGF-β. However, when these cells were challenged with PDL-CTX, only PDL cells migrated in a specific dose-dependent manner, while GF were refractive to PDL-CTX stimulation. Additionally, concentrated conditioned culture media from cultures of gingival fibroblasts did not stimulate PDL cell migratory responses. In other experiments, antibody directed against PDGF, FGF, TGF-β, IGF-I, IGF-II, NGF, and EGF did not inhibit the PDL-CTX-elicited response in PDL cells. Previous studies have suggested that success of periodontal therapy depends on the specific attachment, migration, and proliferation of selected periodontal ligament cells. The data presented in this manuscript suggest that both PDL cells and gingival fibroblasts respond to a multitude of growth factors. PDL-CTX was found to be PDL-cell-specific for directed migration. Thus, we conclude that any biological therapeutic regime for periodontal regeneration should include PDL-cell-specific agents.

Glucose-mediated Alteration of Cellular Function in Human Periodontal Ligament Cells

Because diabetic patients are easily led to manifest severe periodontitis, we wanted to determine whether various glucose levels interfere with normal cellular function. Human periodontal ligament (PDL) cells were cultured in glucose-free medium, or in medium containing either 1100 mg/L of glucose (normal-glucose medium) or 4500 mg/L of glucose (high-glucose medium). Cells cultured in glucose-free medium changed their morphology from spindle-shaped to round, and incorporated trypan blue in a time-dependent manner. The incorporation rate was much faster in cells with shorter cell cycles than in those with longer cycles, suggesting the involvement of cell-cycle progression in cell death. However, fragmented DNA, which suggests apoptotic cell death, was not observed in these cells. We reasoned that initial cell rounding and detachment from the culture plate might be due to the conformational changes in cell-surface receptors to fibronectin, a major extracellular matrix for fibroblasts. Western blot analysis revealed that cells cultured in glucose-free medium lost their fibronectin receptor in a time-dependent manner. In addition, fibronectin receptor expression was much higher in cells cultured in high-glucose medium than in cells cultured in normal-glucose medium. Furthermore, the over-expression of the fibronectin receptor resulted in a suppressed chemotactic response of these cells to platelet-derived growth factor. On the basis of these data, it was hypothesized that a high glucose level induced over-expression of these receptors. This might be the mechanism by which a high glucose level compromises wound healing in diabetic patients and, at least in part, might be the reason diabetic patients are subject to severe periodontal destruction.

T cell responses to 53-kDa outer membrane protein of Porphyromonas gingivalis in humans with early-onset periodontitis.

Patients with early-onset periodontitis (EOP) are susceptible to infection with periodontopathic bacteria, such as Porphyromonas gingivalis. Ag53, 53-kDa outer membrane protein of P. gingivalis, evokes strong humoral immune responses in EOP patients. In a first step to clarify how host immune cells recognize Ag53, we established Ag53-specific short-term T cell lines from 22 subjects including 6 EOP patients and 16 healthy donors, using overlapping peptides based on Ag53 amino acid sequences. All T cell lines from active EOP patients recognized a common region (p141-181, especially p141-161) on Ag53, while those from healthy donors showed heterogeneous specificity. p141-181 was not recognized by T cell lines established from EOP patients following therapy. A monoclonal antibody to HLA-DRB 1 inhibited Ag53-induced proliferation of most of the T cell lines. Our observations suggest that, although antigen-presenting molecules are common in EOP patients and in healthy individuals, p141-161 includes a major T cell epitope(s) on Ag53 for active EOP patients but not for healthy individuals or inactive EOP patients.

Haptotactic migration of pancreatic cancer cells induced by bioactive components in bovine liver extract

Background and Objectives: Migration into subendothelial tissue in remote organ by cancer cells are crucial events for organ‐specific metastasis, including liver metastasis. This study aims to investigate the chemoattractive ingredients in liver extract, which induce migration of liver metastatic cancer cells.

Effect of TNF-.ALPHA. on DNA Synthesis and Extracellular Matrix Protein Synthesis in Human Gingival Fibroblasts.

腫瘍壊死因子 (TNF) -αは, 初期の炎症反応として産生される炎症性サイトカインのひとつで, 炎症病巣の成立に関与していると考えられている。我々は, 歯肉結合組織におけるTNF-αの役割を理解するために, ヒト歯肉線維芽細胞のDNA合成, コラーゲン合成, および非コラーゲン蛋白合成に対するTNF-αの作用を, 線維芽細胞自らが産生するプロスタグランジン (PG) E2, および血小板成長因子 (PDGF) のオートクラインな影響を考慮して調べた。結果は以下の通りである。1) TNF-αはヒト歯肉線維芽細胞におけるDNA合成, コラーゲン合成, および非コラーゲン蛋白合成を促進した。2) TNF-αはヒト歯肉線維芽細胞におけるPGE2産生を著明に促進した。3) インドメタシンを用いてPGE2産生を阻害することにより, TNF-αがヒト歯肉線維芽細胞におけるDNA合成, コラーゲン合成, および非コラーゲン蛋白合成を促進する効果を増強した。4) TNF-αはヒト歯肉線維芽細胞におけるPDGF-A鎖mRNAの発現を促進した。以上の結果から, TNF-αはヒト歯肉線維芽細胞のDNA合成および細胞外基質蛋白合成に対し促進的に作用することが明らかとなった。また, これらの作用は, TNF-αが産生を誘導するPGE2によって抑制を受けていた。さらにTNF-αがDNA合成を促進する作用には, 内因性PDGFが関与している可能性が示唆された。