Difesa e Biotecnologie Agro-Forestali, Dipartimento di Biologia, Università della Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy.
Insect Biochem Mol Biol. 2012 Mar;42(3):203-11. doi: 10.1016/j.ibmb.2011.11.011. Epub 2011 Dec 22.
The innate immune system of insects consists of humoural and cellular responses that provide protection against invading pathogens and parasites. Defence reactions against these latter include encapsulation by immune cells and targeted melanin deposition, which is usually restricted to the surface of the foreign invader, to prevent systemic damage. Here we show that a protein produced by haemocytes of Heliothis virescens (Lepidoptera, Noctuidae) larvae, belonging to XendoU family, generates amyloid fibrils, which accumulate in large cisternae of the rough endoplasmic reticulum and are released upon immune challenge, to form a layer coating non-self objects entering the haemocoel. This amyloid layer acts as a molecular scaffold that promotes localised melanin synthesis and the adhesion of immune cells around the non-self intruder during encapsulation response. Our results demonstrate a new functional role for these protein aggregates that are commonly associated with severe human diseases. We predict that insects will offer new powerful experimental systems for studying inducible amyloidogenesis, which will likely provide fresh perspectives for its prevention.
昆虫的先天免疫系统包括体液和细胞反应，可提供针对入侵病原体和寄生虫的保护。针对后者的防御反应包括免疫细胞的包被和靶向黑色素沉积，通常仅限于外来入侵者的表面，以防止全身性损伤。在这里，我们表明，来自 Heliothis virescens（鳞翅目，夜蛾科）幼虫血细胞的一种属于 XendoU 家族的蛋白质产生淀粉样原纤维，这些纤维在粗面内质网的大池状结构中积累，并在免疫挑战时释放，以形成覆盖进入血腔的非自身物体的层。这种淀粉样层作为分子支架，促进局部黑色素合成，并在包被反应期间将免疫细胞黏附在非自身入侵物周围。我们的结果证明了这些通常与严重人类疾病相关的蛋白聚集体的新功能作用。我们预测昆虫将为研究诱导性淀粉样变提供新的强大实验系统，这可能为其预防提供新的视角。
