Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Front Cell Infect Microbiol. 2020 Feb 7;10:31. doi: 10.3389/fcimb.2020.00031. eCollection 2020.
(formerly genotype-II) is an opportunistic, achlorophyllous alga that causes mastitis in cows and skin disease in cats and dogs, as well as cutaneous lesions in both immunocompetent and immunosuppressed humans. Antifungal medications are commonly ineffective. This study aimed to investigate innate immune responses contributed by cathelicidins to in the mammary gland using a mastitis model in mice deficient in the sole murine cathelicidin (). We determined caused acute mastitis in mice and induced gene transcription. Whereas, and littermates had similar local algae burden, mice produced more pro-inflammatory cytokines, TNF-α, and Cxcl-1. Likewise, bone marrow-derived macrophages were more responsive to , producing more α and . Human cathelicidin (LL-37) exhibited a different effect against ; it had direct algicidal activity against and lowered α, Cxcl-1, and β production in both cultured murine macrophages and mammary epithelial cells exposed to the pathogenic algae. In conclusion, cathelicidins were involved in protothecosis pathogenesis, with unique roles among the diverse peptide family. Whereas, endogenous cathelicidin () was key in mammary gland innate defense against , human LL-37 had algicidal and immunomodulatory functions.
（以前称为基因型-II）是一种机会性、无叶绿素的藻类，可引起奶牛乳腺炎、猫和狗的皮肤病，以及免疫功能正常和免疫抑制的人类的皮肤损伤。抗真菌药物通常无效。本研究旨在使用缺乏唯一的鼠源抗菌肽（）的乳腺炎模型，研究抗菌肽对乳腺中 的先天免疫反应的贡献。我们发现 在小鼠中引起急性乳腺炎，并诱导 基因转录。然而， 和 同窝仔鼠的局部藻类负担相似， 小鼠产生更多的促炎细胞因子 TNF-α 和 Cxcl-1。同样， 骨髓来源的巨噬细胞对 反应更敏感，产生更多的 和 。人源抗菌肽（LL-37）对 有不同的作用；它对 具有直接的杀藻活性，并降低暴露于致病性藻类的培养鼠巨噬细胞和乳腺上皮细胞中 的 、Cxcl-1 和 的产生。总之，抗菌肽参与了原绿球藻病的发病机制，在不同的肽家族中具有独特的作用。然而，内源性抗菌肽（）是乳腺先天防御 的关键，人源 LL-37 具有杀藻和免疫调节功能。
