The role of endogenous antibiotics, Cathelicidin in liver regeneration

内源性抗生素 Cathelicidin 在肝再生中的作用

• 批准号: 15590612
• 负责人: OHTAKE Takaaki
• 金额: $ 2.18万
• 依托单位: Asahikawa Medical College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590612/
• 关键词: innate immunity; antimicrobial peptide; cathelicidin; CRAMP; PR-39; Toll like receptor; bacterial infection; 内因性抗生物質; 肝再生

The mechanism of host defense of Vertebrates consists of both acquired and innate immune systems. The former is the specific system of Vertebrates. The recognition of pathogens by immunoglobulin or T cell receptor is specific. On the other hand the later exists universally in the lower animals such as insect. It has the important role for the host defense with the front line of pathogens. Cathelicidins are mammalian endogenous antibiotic, which works as the effecter molecule of innate immunity, induces the synthesis of a transmembrane heparin sulphate proteoglycan involved in co-factor of epidermal growth factor receptor (EGFR) in skin wound healing. Previously we revealed that the importance of the host defense in skin infection model (Nature,2001) and the lack of the expression of cathelicidin is the cause of secondary infection in atopic dermatitis (N Engl J Med,2002). Furthermore, porcine cathelicidin, PR-39 induce angiogenesis in model of rat myocardial infarction. Existence of ca … More thelicidin in macrophage, and stimuli by lipopolysacchaloid (LPS) induce the expression of cathelicidin via Toll like receptor (TLR). Recently the importance of Kupffer cells in liver regeneration is reported. We hypotheses that cathelicidin in Kupffer cell could induce proliferation of hepatocytes directly and indirectly. Actually we revealed that the expression of mRNA of TLR-3 to 8 and 10 in normal liver tissue by RTPCR. However we could reveal that the signals of expression of cathelicidin in recruiting neutrophils but not Kupffer cells in normal liver tissue. Therefore for investigation and evaluation of bactericidal activity and tissue healing activity, we used mouse skin infection model and generated two cathelicidin transgenic mice.Cathelicidin antimicrobial peptides are effectors of innate immune defense in mammals. Humans and mice have only one cathelicidin gene, whereas domesticated mammals such as the pig, cow, and horse have multiple cathelicidin genes. We hypothesized that the evolution of multiple cathelicidin genes provides these animals with enhanced resistance to infection. To test this, we investigated the effects of the addition of cathelicidins by combining synthetic cathelicidin peptides in vitro, by producing human keratinocytes that overexpress cathelicidins in culture, or by producing transgenic mice that constitutively overexpress cathelicidins in vivo. The porcine cathelicidin peptide PR-39 acted additively with human cathelicidin LL-37 to kill group A Streptococcus (GAS). Lentiviral delivery of PR-39 enhanced killing of GAS by human keratinocytes. Finally, transgenic mice expressing PR-39 under the influence of a K14 promoter showed increased resistance to GAS skin infection (50% smaller necrotic ulcers and 60% fewer surviving bacteria). Similarly constructed transgenic mice designed to overexpress their native cathelicidin did not show increased resistance. These findings demonstrate that targeted gene transfer of a xenobiotic cathelicidin confers resistance against infection and suggests the benefit of duplication and divergence in the evolution of antimicrobial peptides. Less

脊椎动物的宿主防御机制包括获得性免疫系统和先天性免疫系统，前者是脊椎动物特有的免疫球蛋白或T细胞受体识别病原体的系统，而后者普遍存在于低等动物中。例如昆虫，它对于宿主防御病原体的前线具有重要作用，Cathelicidins是哺乳动物内源性抗生素，作为先天免疫的效应分子，诱导一种抗生素的合成。跨膜硫酸肝素蛋白聚糖参与皮肤伤口愈合中表皮生长因子受体（EGFR）的辅因子，之前我们揭示了皮肤感染模型中宿主防御的重要性（Nature，2001）以及导管素表达的缺乏。特应性皮炎继发感染的原因（N Engl J Med，2002）。此外，猪导管素、PR-39 诱导血管生成在大鼠心肌梗死模型中，巨噬细胞中存在 ca … More thelicidin，并且脂多糖 (LPS) 的刺激可通过 Toll 样受体 (TLR) 诱导抗菌肽的表达，最近我们提出了 Kupffer 细胞在肝再生中的重要性。 Kupffer细胞中的cathelicidin可以直接和间接诱导肝细胞增殖，实际上我们发现TLR-3 mRNA的表达对肝细胞增殖有影响。通过RTPCR在正常肝组织中观察到图8和10，但是我们可以揭示在正常肝组织中募集中性粒细胞而不是库普弗细胞中表达的导管素的信号，因此为了研究和评估杀菌活性和组织愈合活性，我们使用小鼠皮肤。感染模型并产生两只cathelicidin转基因小鼠。Cathelicidin抗菌肽是哺乳动物先天免疫防御的效应物，人类和小鼠只有一种cathelicidin。基因，而家养哺乳动物，如猪、牛和马，具有多个导管素基因，我们发现多个导管素基因的进化为这些动物提供了增强的感染抵抗力。为了测试这一点，我们研究了添加导管素的效果。通过在体外组合合成的导管素肽，通过产生在培养物中过度表达导管素的人角质形成细胞，或通过产生在培养物中组成型过度表达导管素的转基因小鼠猪抗菌素肽 PR-39 与人抗菌素 LL-37 共同作用，杀死 A 族链球菌 (GAS)。慢病毒递送 PR-39 增强了人角质形成细胞对 GAS 的杀伤作用。 K14 启动子的影响显示出对 GAS 皮肤感染的抵抗力增强（坏死性溃疡缩小 50%，存活细菌减少 60%）。构建的旨在过度表达其天然抗菌素的转基因小鼠并未表现出抵抗力的增加。这些发现同样表明，异生抗菌素的靶向基因转移赋予了对感染的抵抗力，并表明了抗菌肽进化中的重复和分歧的好处。

项目成果

Expression of an additional cathelicidin antimicrobial peptide protects against bacterial skin infection

• DOI: 10.1073/pnas.0500268102
• 发表时间: 2005-03-08
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Lee, PHA;Ohtake, T;Gallo, RL
• 通讯作者: Gallo, RL