A drug development study for a periodontal disease : Biological properties of synthetic lipid A of Porphyromonas gingivalis lipopolysaccharide

化学合成在从牙龈卟啉单胞菌LPS分离的脂质A中发现的五酰基和二磷酰基脂质A分子（J Bacteriol 1995：177：2098），并评价其特征以再次确认其令人感兴趣的生物活性，包括低内毒性和对LPS-无应答的C3 H/HeJ小鼠细胞的活性。合成的牙龈卟啉单胞菌脂质A（合成的Pg-LA）在对LPS应答小鼠和细胞的所有测定中表现出几乎与大肠杆菌型合成脂质A（化合物506）相当的强活性。牙龈卟啉单胞菌的LPS和天然脂质A显示出总体内毒素活性，但与合成类似物相比，其效力降低。在使用C3 H/HeJ小鼠细胞的测定中，LPS和天然脂质A显著刺激脾细胞以引起有丝分裂，并刺激腹膜巨噬细胞以诱导TNF-D和IL-6产生。然而，合成的Pg-LA和化合物506对LPS无反应的细胞没有显示出活性。抑制试验使用一些i ...更多信息 包括抗人TLR 2和TLR 4/MD-2复合物单克隆抗体的抑制剂显示，合成的Pg-LA的生物活性仅通过可能作为LPS受体的TLR 4信号传导途径介导，而TLR 2，可能与CD 14一起，除了TLR 4途径之外，还与LPS和牙龈卟啉单胞菌的天然脂质A的信号传导级联相关。这些结果表明，牙龈卟啉单胞菌LPS和天然脂质A的适度和降低的生物活性，包括通过TLR 2介导的途径对C3 H/HeJ小鼠细胞的活性，可能是由具有多个脂质A部分的天然制剂中存在的生物活性污染物或低酰化分子介导的。这些发现表明牙龈卟啉单胞菌LPS和天然脂质A的生物活性，包括通过TLR 2介导的途径对C3 H/HeJ小鼠细胞的活性，可由脂质A部分具有高度异质性的天然制剂中存在的生物活性污染物或低酰化分子介导。为了阐明这些问题，我们现在正试图使用每种化学合成的类似物，评估具有牙龈卟啉单胞菌天然脂质A中发现的主要分子的四酰化单磷酸化或二磷酸化物质的生物学特性。少

A pentaacyl and diphosphoryl lipid A molecule (J Bacteriol 1995: 177: 2098) found in the lipid A isolated from P. gingivalis LPS was chemically synthesized, and its characteristics were evaluated to reconfirm its interesting bioactivities including low endotoxicity and activity against LPS-unresponsive C3H/HeJ mouse cells. The synthesized P. gingivalis lipid A (synthetic Pg-LA) exhibited strong activities almost equivalent to those of Escherichia coli-type synthetic lipid A (compound 506) in all assays on LPS-responsive mice, and cells. LPS and native lipid A of P. gingivalis displayed overall endotoxic activities, but its potency was reduced in comparison to the synthetic analogs. In the assays using C3H/HeJ mouse cells, the LPS and native lipid A significantly stimulated splenocytes to cause mitosis, and peritoneal macrophages to induce TNF-D and IL-6 production. However, synthetic Pg-LA and compound 506 showed no activity on the LPS-unresponsive cells. Inhibition assays using some i … More nhibitors including anti-human TLR 2 and TLR4/MD-2 complex monoclonal antibodies showed that the biological activity of synthetic Pg-LA was mediated only through the TLR4 signaling pathway that might act as a receptor for LPS, whereas TLR2, possibly together with CD14, was associated with the signaling cascade for LPS and native lipid A of P. gingivalis, in addition to the TLR4 pathway. These results suggested that the moderated and reduced biological activity of P. gingivalis LPS and native lipid A, including the activity on C3H/HeJ mouse cells by TLR2-mediated pathway, may be mediated by bioactive contaminants or low acylated molecules present in the native preparations having multiple lipid A moieties.In conclusion, these findings suggested that the moderated and reduced biological activity of P. gingivalis LPS and native lipid A, including the activity on C3H/HeJ mouse cells by TLR2-mediated pathway, may be mediated by bioactive contaminants or low acylated molecules present in the native preparations having high heterogeneity in lipid A moiety. To elucidate these problems, we are now attempting to evaluate the biological characterizations of tetra-acylated monophosphorylated or diphosphorylated species with the predominant molecules found in P. gingivalis native lipid A, using each chemically synthesized analog. Less