Shrestha Chandra L, Assani Kaivon D, Rinehardt Hannah, Albastroiu Florentina, Zhang Shuzhong, Shell Richard, Amer Amal O, Schlesinger Larry S, Kopp Benjamin T
Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America.
Section of Pediatric Pulmonology, Nationwide Children's Hospital, Columbus, Ohio, United States of America.
PLoS One. 2017 Oct 5;12(10):e0186169. doi: 10.1371/journal.pone.0186169. eCollection 2017.
Members of the Burkholderia cepacia complex are virulent, multi-drug resistant pathogens that survive and replicate intracellularly in patients with cystic fibrosis (CF). We have discovered that B. cenocepacia cannot be cleared from CF macrophages due to defective autophagy, causing continued systemic inflammation and infection. Defective autophagy in CF is mediated through constitutive reactive oxygen species (ROS) activation of transglutaminase-2 (TG2), which causes the sequestration (accumulation) of essential autophagy initiating proteins. Cysteamine is a TG2 inhibitor and proteostasis regulator with the potential to restore autophagy. Therefore, we sought to examine the impact of cysteamine on CF macrophage autophagy and bacterial killing. Human peripheral blood monocyte-derived macrophages (MDMs) and alveolar macrophages were isolated from CF and non-CF donors. Macrophages were infected with clinical isolates of relevant CF pathogens. Cysteamine caused direct bacterial growth killing of live B. cenocepacia, B. multivorans, P. aeruginosa and MRSA in the absence of cells. Additionally, B. cenocepacia, B. multivorans, and P. aeruginosa invasion were significantly decreased in CF MDMs treated with cysteamine. Finally, cysteamine decreased TG2, p62, and beclin-1 accumulation in CF, leading to increased Burkholderia uptake into autophagosomes, increased macrophage CFTR expression, and decreased ROS and IL-1β production. Cysteamine has direct anti-bacterial growth killing and improves human CF macrophage autophagy resulting in increased macrophage-mediated bacterial clearance, decreased inflammation, and reduced constitutive ROS production. Thus, cysteamine may be an effective adjunct to antibiotic regimens in CF.
洋葱伯克霍尔德菌复合体的成员是毒性强、多重耐药的病原体，可在囊性纤维化（CF）患者体内细胞内存活并复制。我们发现，由于自噬缺陷，洋葱伯克霍尔德菌无法从CF巨噬细胞中清除，从而导致持续的全身炎症和感染。CF中的自噬缺陷是通过转谷氨酰胺酶2（TG2）的组成型活性氧（ROS）激活介导的，这会导致自噬起始必需蛋白的隔离（积累）。半胱胺是一种TG2抑制剂和蛋白质稳态调节剂，具有恢复自噬的潜力。因此，我们试图研究半胱胺对CF巨噬细胞自噬和细菌杀伤的影响。从CF和非CF供体中分离出人外周血单核细胞衍生的巨噬细胞（MDM）和肺泡巨噬细胞。巨噬细胞用相关CF病原体的临床分离株进行感染。半胱胺在无细胞的情况下对活的洋葱伯克霍尔德菌、多食伯克霍尔德菌、铜绿假单胞菌和耐甲氧西林金黄色葡萄球菌具有直接的细菌生长杀伤作用。此外，用半胱胺处理的CF MDM中，洋葱伯克霍尔德菌、多食伯克霍尔德菌和铜绿假单胞菌的入侵显著减少。最后，半胱胺降低了CF中TG2、p62和beclin-1的积累，导致伯克霍尔德菌被自噬体摄取增加、巨噬细胞CFTR表达增加，以及ROS和IL-1β产生减少。半胱胺具有直接的抗菌生长杀伤作用，并改善人CF巨噬细胞自噬，从而导致巨噬细胞介导的细菌清除增加、炎症减轻和组成型ROS产生减少。因此，半胱胺可能是CF抗生素治疗方案的有效辅助药物。
