Alterations of the Coxiella burnetii Replicative Vacuole Membrane Integrity and Interplay with the Autophagy Pathway.
Alterations of the Coxiella burnetii Replicative Vacuole Membrane Integrity and Interplay with the Autophagy Pathway.
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DOI：
10.3389/fcimb.2017.00112
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发表时间：
2017
影响因子：
5.7
通讯作者：
Colombo MI
中科院分区：
文献类型：
--
作者：
Mansilla Pareja ME;Bongiovanni A;Lafont F;Colombo MI
伯纳克希菌是Q热的病原，是一种革兰氏阴性专性细胞内细菌。以前已经描述过内吞和自噬途径都有助于科希氏菌复制液泡（CRV）的产生。半乳糖凝集素是β-半乳糖苷结合的凝集素，在通过非常规的分泌途径分泌之前积聚在细胞质中。研究表明，半乳糖凝集素-3、-8、-9通过与暴露在细胞质中的宿主聚糖结合，监测细菌空泡破裂以及膜完整性的丧失。通过显微注射荧光偶联葡聚糖、FRET测定和凝集素分布，我们证明了柯希氏菌感染实际上以Dot/ icm依赖的方式导致短暂的吞噬体/CRV膜损伤。我们还展示了参与自噬的不同接头分子和LC3与CRV的限制膜的关联。此外，我们发现自噬抑制后，标记有凝集素和酸化程度较低的crv的比例增加，这与细菌复制损伤有关。基于这些观察，我们提出自噬可以促进细胞内受损膜的重新密封。
Coxiella burnetii, the etiologic agent of Q fever, is a Gram-negative obligate intracellular bacterium. It has been previously described that both the endocytic and autophagic pathways contribute to the Coxiella replicative vacuole (CRV) generation. Galectins are β-galactoside-binding lectins that accumulate in the cytosol before being secreted via a non-conventional secretory pathway. It has been shown that Galectin-3, -8, -9 monitor bacteria vacuolar rupture and endosomal and lysosomal loss of membrane integrity through binding of host glycans exposed in the cytoplasm after membrane damage. Using microinjection of fluorescence-coupled dextrans, a FRET assay, and galectins distribution, we demonstrate that Coxiella infection actually result in transient phagosomal/CRV membrane damage in a Dot/Icm-dependent manner. We also show the association of different adaptor molecules involved in autophagy and of LC3 to the limiting membrane of the CRV. Moreover, we show that upon autophagy inhibition, the proportion of CRVs labeled with galectins and less acidified increases which is associated with bacteria replication impairment. Based on these observations, we propose that autophagy can facilitate resealing of intracellular damaged membranes.