Chevriaux Angélique, Pilot Thomas, Derangère Valentin, Simonin Harmonie, Martine Pierre, Chalmin Fanny, Ghiringhelli François, Rébé Cédric
INSERM Lipid Nutrition and Cancer UMR 1231, Dijon, France.
Centre Georges François Leclerc, Dijon, France.
Front Cell Dev Biol. 2020 Mar 31;8:167. doi: 10.3389/fcell.2020.00167. eCollection 2020.
The mechanisms leading to NOD-leucine rich repeat and pyrin containing protein 3 (NLRP3) inflammasome activation are still debated. It is well established that oligomerized NLRP3 interacts with apoptosis associated Speck-like protein containing a CARD domain (ASC) which polymerizes into filaments recruiting procaspase-1, leading to its activation. However, pathways triggering NLRP3 activation, such as potassium efflux, ROS production or lysosomal permeabilization, can be required or not, depending on the activators used. Here we proposed to evaluate the importance of Cathepsin B on NLRP3 inflammasome assembly and activation. Using Cathepsin B BMDMs (Bone Marrow-Derived Macrophages), we first show that Cathepsin B is required for caspase-1 activation, IL-1β production and ASC speck formation, upon treatment with different types of NLRP3 activators, i.e., ATP, nigericin or crystals. Moreover, in these conditions, Cathepsin B interacts with NLRP3 at the endoplasmic reticulum (ER) level. To conclude, different NLRP3 activators lead to Cathepsin B interaction with NLRP3 at the ER level and to subsequent caspase-1 activation.
导致含核苷酸结合寡聚化结构域样受体蛋白3（NLRP3）炎性小体激活的机制仍存在争议。众所周知，寡聚化的NLRP3与含半胱天冬酶激活和招募结构域的凋亡相关斑点样蛋白（ASC）相互作用，ASC聚合成细丝招募前半胱天冬酶-1，导致其激活。然而，触发NLRP3激活的途径，如钾外流、活性氧生成或溶酶体通透性改变，是否需要取决于所使用的激活剂。在此，我们旨在评估组织蛋白酶B对NLRP3炎性小体组装和激活的重要性。使用组织蛋白酶B基因敲除的骨髓来源巨噬细胞（BMDMs），我们首先表明，在用不同类型的NLRP3激活剂（即ATP、尼日利亚菌素或晶体）处理后，组织蛋白酶B是半胱天冬酶-1激活、白细胞介素-1β产生和ASC斑点形成所必需的。此外，在这些条件下，组织蛋白酶B在内质网（ER）水平与NLRP3相互作用。总之，不同的NLRP3激活剂导致组织蛋白酶B在内质网水平与NLRP3相互作用，并随后激活半胱天冬酶-1。
