Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA; Cell and Molecular Biology, University of Arkansas, Fayetteville, AR 72701, USA.
Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA.
Poult Sci. 2022 May;101(5):101750. doi: 10.1016/j.psj.2022.101750. Epub 2022 Jan 30.
Autophagy is a cell survival and homeostasis mechanism involving lysosomal degradation of cellular components and foreign bodies. It plays a role in bone homeostasis, skeletal diseases, and bacterial infections as both a cell-survival or cell-death pathway. This study sought to determine if autophagy played a role in bacterial chondronecrosis with osteomyelitis (BCO). BCO is a prominent cause of lameness in modern broilers and results from bacterial infection of mechanically stressed leg bone growth plates. The protein and gene expression of key autophagy machinery was analyzed in both normal and BCO-affected broilers using real-time qPCR and immunoblot, respectively. Gene expression showed a significant downregulation of key target signatures involved in every stage of autophagy in BCO-affected bone, such as ATG13, SQSTM1 (p62), ATG9B, ATG16L, ATG12, LC3C, and RAB7A. Additionally, protein expression for LC3 was also significantly lower in BCO. An in vitro study using human fetal osteoblast cells challenged with BCO isolate, Staphylococcus agnetis 908, showed a similar dysregulation of autophagy machinery along with a significant decrease in cell viability. When autophagy was inhibited via 3-methyladenine or chloroquine, comparable decreases in cell viability were seen along with dysregulation of autophagy machinery. Together, these results are the first to implicate autophagy machinery dysregulation in the pathology of BCO.
自噬是一种细胞存活和体内平衡机制，涉及溶酶体降解细胞成分和异物。它在骨稳态、骨骼疾病和细菌感染中发挥作用，既是细胞存活途径，也是细胞死亡途径。本研究旨在确定自噬是否在细菌性软骨坏死伴骨髓炎（BCO）中发挥作用。BCO 是现代肉鸡跛行的主要原因，是由于细菌感染机械应激腿骨生长板引起的。使用实时 qPCR 和免疫印迹分别分析了正常和 BCO 肉鸡中关键自噬机制的蛋白和基因表达。基因表达显示，在 BCO 受累骨中，自噬的每个阶段的关键靶标特征的表达显著下调，如 ATG13、SQSTM1（p62）、ATG9B、ATG16L、ATG12、LC3C 和 RAB7A。此外，BCO 中的 LC3 蛋白表达也显著降低。体外研究使用人胎成骨细胞挑战 BCO 分离株金黄色葡萄球菌 908，显示自噬机制同样失调，细胞活力显著下降。当通过 3-甲基腺嘌呤或氯喹抑制自噬时，细胞活力也会出现类似的下降，同时自噬机制失调。总之，这些结果首次表明自噬机制失调参与了 BCO 的发病机制。
