Huang Danni, Gao Fulong, Huang Yixin, Zheng Ronghui, Fang Chao, Huang Wenshu, Wang Kejian, Bo Jun
Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China; Fisheries College, Jimei University, Xiamen, China.
Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China.
Comp Biochem Physiol C Toxicol Pharmacol. 2025 Mar;289:110091. doi: 10.1016/j.cbpc.2024.110091. Epub 2024 Dec 20.
Cathelicidin is a family of antimicrobial peptides in vertebrates that plays an important role in resistance and immunization against pathogenic microorganisms. In the present study, the full-length cDNA sequences of four novel cathelicidins (cathelicidin-1 to cathelicidin-4) in the tiger frog Hoplobatrachus rugulosus, encoding 153, 188, 132, and 160 amino acids, respectively, were firstly cloned by rapid amplification of the cDNA ends (RACE) technique. Sequence comparison and phylogenetic tree analysis indicated that the structures of the four cathelicidins are highly diverse. Afterwards, the tissue distribution profiles and antimicrobial patterns of cathelicidins in H. rugulosus were determined by real-time PCR. The four cathelicidins showed tissue-specific distribution patterns in the healthy frogs, and the transcriptional levels of cathelicidins exhibited a tissue- and time-dependency profile in the frogs challenged with pathogenic bacteria Aeromonas hydrophila for 72 h. The synthetic peptides of cathelicidin-1 and cathelicidin-2 exhibited broad-spectrum in vitro antimicrobial activity, and cathelicidins exerted antimicrobial activities through excessive induction of reactive oxygen species and direct disruption of the microbial membrane structure. In addition, the intraperitoneal injection of cathelicidin proteins significantly increased the marine medaka Oryzias melastigma resistance to bacterial challenges. The existence of multiple cathelicidins, their distinct tissue distribution patterns, and the inducible expression profiles suggest a sophisticated, highly redundant, and multilevel network of antimicrobial defense mechanisms in tiger frogs. This study provides evidence that cathelicidins have antimicrobial and immunomodulatory activities, and cathelicidins derived from H. rugulosus have potential therapeutic applications against pathogenic infections in aquaculture.
cathelicidin是脊椎动物中的一类抗菌肽，在抵抗和免疫致病微生物方面发挥着重要作用。在本研究中，首次通过cDNA末端快速扩增（RACE）技术克隆了虎纹蛙（Hoplobatrachus rugulosus）中四种新型cathelicidin（cathelicidin-1至cathelicidin-4）的全长cDNA序列，它们分别编码153、188、132和160个氨基酸。序列比较和系统发育树分析表明，这四种cathelicidin的结构高度多样。随后，通过实时PCR确定了虎纹蛙中cathelicidin的组织分布谱和抗菌模式。这四种cathelicidin在健康青蛙中表现出组织特异性分布模式，在用嗜水气单胞菌攻击72小时的青蛙中，cathelicidin的转录水平呈现出组织和时间依赖性分布。cathelicidin-1和cathelicidin-2的合成肽在体外表现出广谱抗菌活性，cathelicidin通过过度诱导活性氧和直接破坏微生物膜结构发挥抗菌活性。此外，腹腔注射cathelicidin蛋白显著提高了青鳉（Oryzias melastigma）对细菌攻击的抵抗力。多种cathelicidin的存在、它们独特的组织分布模式以及诱导表达谱表明虎纹蛙存在一个复杂、高度冗余且多层次的抗菌防御机制网络。本研究提供了证据表明cathelicidin具有抗菌和免疫调节活性，并且源自虎纹蛙的cathelicidin在水产养殖中对病原体感染具有潜在的治疗应用价值。
