マウス破骨細胞形成における抗微生物ペプチド Cathelicidin-related antimicrobial peptide （CRAMP）の役割）

Cathelicidin-related antimicrobial peptide (CRAMP) not only kills bacteria but also binds to lipopolysaccharide (LPS) to neutralize its activity. CRAMP is highly expressed in bone marrow and its expression is reported to be up-regulated by inflammatory and infectious stimuli. Here, we examined the role of CRAMP in murine osteoclastogenesis. Osteoclasts were formed in co-cultures of osteoblasts and bone marrow cells in response to 1a,25-dihydroxyvitamin D3 [1a,25(OH)2D3], prostaglandin E2(PGE2), and Toll-like receptor (TLR) ligands such as LPS and flagellin through the induction of receptor activator of nuclear factor-jB ligand(RANKL) expression in osteoblasts. CRAMP inhibited the osteoclastogenesis in co-cultures treated with LPS and flagellin, but not in those treated with 1a,25(OH)2D3 or PGE2. Although bone marrow macrophages(BMMs) highly expressed formyl peptide receptor 2 (a receptor of CRAMP), CRAMP showed no inhibitory effect on osteoclastogenesis in BMM cultures treated with RANKL. CRAMP suppressed both LPS- and flagellin-induced RANKL expression in osteoblasts and tumour necrosis factor-a (TNF-a) expression in BMMs, suggesting that CRAMP neutralizes the actions of LPS and flagellin. LPS and flagellin enhanced the expression of CRAMP mRNA in osteoblasts. Extracellularly added CRAMP suppressed LPS- and flagellin-induced CRAMP expression. These results suggest that the production of CRAMP promoted by LPS and flagellin is inhibited by CRAMP released by osteoblasts through a feedback regulation. Even though CRAMP itself has no effect on osteoclastogenesis in mice, we propose that CRAMP is an osteoblast-derived protector in bacterial infection-induced osteoclastic bone resorption.2013博士（歯学）松本歯科大

Detection by western blotting of an antibody to the hepatitis C virus E1 envelope protein in sera of patients with chronic liver disease.

We detected an antibody to HCV envelope protein (E1) in sera of patients with HCV-related chronic liver diseases (20 patients with chronic hepatitis and 5 patients with liver cirrhosis) by Western blotting using the fusion protein of E1 envelope protein and beta-galactosidase as an antigen. The antibody to HCV E1 (anti-HCV E1) was detected in 8 (42%) of 19 patients positive for HCV-RNA (16 were positive and 3 were negative for antibody to C100-3) and in 1 (17%) of 6 patients negative for HCV-RNA but positive for antibody to C100-3. HCV-RNA was detected in 8 (89%) of 9 anti-HCV E1 positive sera. The value of alanine aminotransferase was significantly higher in patients positive for anti-HCV E1 than in patients negative for the antibody. Although an antibody to the envelope protein of HCV is suspected to be one of the candidates of virus-neutralizing antibodies, our results suggest this hypothesis appears to be unlikely.</p

骨芽細胞系列細胞のビタミンD受容体は、in vivo において1α,25(OH)2D3の骨吸収促進活性に必須である

要旨我々は以前、活性型ビタミンD3 [1α,25(OH)2D3]製剤であるエルデカルシトールの薬用量の投与は、骨吸収を抑制することで、骨量を増加させることを報告した。この骨吸収抑制効果は、骨芽細胞系列細胞のビタミンD受容体（VDR）を介することを明らかにした。本研究において我々は、骨芽細胞系列細胞特異的VDR欠損（Ob-VDR-cKO）マウスを用いて、1α,25(OH)2D3の大量投与によって誘導される骨吸収促進が骨芽細胞系列細胞のVDRを介するか否かを調べた。4日間の野生型マウスへの1α,25(OH)2D3（5 µg/kg体重/日）投与は、骨における破骨細胞数を増加させ、骨吸収マーカーであるI型コラーゲンC末端テロペプチド（C-terminal crosslinked telopeptide of type I collagen, CTX-I）の血清濃度を上昇させた。骨吸収促進は、血清カルシウム（Ca）値、線維芽細胞増殖因子23（Fibroblast Growth Factor, FGF-23）値の上昇と、体重の減少を伴っていた。このことは、中毒量の1α,25(OH)2D3は、骨吸収促進と高Ca血症を誘導することを示している。対照的に、野生型マウスへの抗Receptor Activator of NF-κB Ligand（RANKL）中和抗体前投与は、1α,25(OH)2D3が誘導する血清CTX-I, CaおよびFGF23値の上昇を抑制した。また、抗RANKL中和抗体前投与は、1α,25(OH)2D3が誘導する体重減少を抑制した。抗RANKL中和抗体前投与マウスの所見と一致して、1α,25(OH)2D3をOb-VDR-cKOマウスに大量投与しても、破骨細胞数、血清CTX-I値、血清Ca値、血清FGF-23値は、有意に上昇せず、また体重も減少しなかった。以上、本研究において、1α,25(OH)2D3の大量投与による骨吸収促進、血清Ca値上昇および毒性作用は、骨芽細胞系列細胞のVDRを介して発揮されることを明らかにした。2020博士（歯学）松本歯科大