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免疫系统。前者是脊椎动物特有的系统。免疫球蛋白或T细胞受体对病原体的识别具有特异性。另一方面，后者普遍存在于昆虫等低等动物中。它对病原菌前线的寄主防御具有重要作用。头孢菌素是哺乳动物内源性抗生素，作为天然免疫的效应分子，可诱导合成一种跨膜型硫酸肝素蛋白多糖，参与皮肤创面愈合过程中的表皮生长因子受体(EGFR)辅助因子。此前，我们揭示了宿主防御在皮肤感染模型中的重要性(自然，2001)和异位性皮炎继发感染的原因(N Engl J Med，2002)。此外，猪内毒素、PR-39可诱导大鼠心肌梗死模型血管生成。CA…的存在巨噬细胞中更多的杀菌素和脂多糖(LPS)的刺激通过Toll样受体(TLR)诱导杀菌素的表达。最近有报道指出枯否细胞在肝脏再生中的重要作用。我们假设枯否细胞中的长春花碱可以直接或间接地诱导肝细胞的增殖。实际上，我们通过RT-PCR发现TLR-3、TLR-8和TLR-10在正常肝组织中表达。然而，我们可以发现，在正常肝组织中，中性粒细胞表达的信号不是库普弗细胞，而是中性粒细胞。因此，为了研究和评价杀菌活性和组织修复活性，我们采用小鼠皮肤感染模型，制备了两只长春花素转基因小鼠。长春花素抗菌肽是哺乳动物天然免疫防御的效应物。人类和老鼠只有一个放线菌素基因，而驯化的哺乳动物，如猪、牛和马，有多个放线菌素基因。我们假设多个放线菌素基因的进化为这些动物提供了对感染的增强抵抗力。为了检验这一点，我们通过在体外结合合成的长春花素多肽，通过在培养中产生过表达长春花素的人角质形成细胞，或通过在体内产生构成高表达长春花素的转基因小鼠，来研究添加长春花素的效果。猪血清肽PR-39与人血凝素LL-37相加作用，可杀灭A组链球菌(GAS)。慢病毒传递PR-39增强人角质形成细胞对GAS的杀伤作用。最后，在K14启动子的影响下表达PR-39的转基因小鼠对气体皮肤感染的抵抗力增强(坏死性溃疡减少50%，存活细菌减少60%)。同样构建的转基因小鼠旨在过度表达它们的天然长春花素，但没有表现出更强的抵抗力。这些发现表明，靶向基因转移的异源长春花碱提供了对感染的抵抗力，并表明了抗菌肽在进化过程中复制和分化的好处。较少

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