Regulation Of Immune Responses In Humans and in Experimental Animals

在巨噬细胞/树突状细胞中LRRK2信号传导功能的初步研究中，我们确定来自携带LRRK2转基因的小鼠的细胞在暴露于通过激活SYK刺激细胞的先天配体时表现出增加的细胞因子应答，SYK是参与dectin受体信号传导并且在较小程度上参与TLR信号传导的细胞表面信号传导分子。 这一点，加上在蛋白质印迹研究中我们确定LRRK2与SYK以及下游SYK相关信号复合物的组分相互作用的事实，BCL 10/MALT-1/CARD 9为LRRK2作为SYK信号通路的组分的想法提供了重要的支持。 在更具体地解决LRRK2如何影响自噬的研究中，我们发现，有点令我们惊讶的是，来自LRRK2转基因小鼠的巨噬细胞在刺激dectin途径后表现出LC3向LC3 II的转化减少，后者是一种出现在活化的自噬途径远端的分子。 来自LRRK2缺陷小鼠的巨噬细胞的补充研究表明，LRRK2缺陷与自噬增加相关，从而证实了用转基因细胞获得的结果。 在解决LRRK2介导的自噬抑制的分子机制问题的其他研究中，我们表明LRRK2与自噬引发剂beclin相互作用，并且这种相互作用与beclin二聚体的分解有关。 Beclin的分解可能由半胱天冬酶8介导，因为LRRK2也与半胱天冬酶8相互作用，后者是上述BCL 10信号传导复合物的组分。 其他实验室的最新研究表明，自体缝合导致激活抑制，也导致IL-1 β信号转导紊乱。 因此，目前的研究表明，LRRK2多态性导致克罗恩病炎症的机制之一是，这些多态性导致自噬相关的缺陷，在正常调节促炎性炎性体/IL-1 β分泌。

In initial studies of LRRK2 signaling function in macrophages/dendritic cells we established that cells from mice bearing an LRRK2 transgene manifest increased cytokine responses when exposed to innate ligands that stimulate cells by activating SYK, a cell surface signaling molecule involved in dectin receptor signaling and to a lesser extent in TLR signaling. This, plus the fact that in Western blot studies we determined that LRRK2 interacts with SYK as well as with components of the downstream SYK-associated signaling complex, BCL10/MALT-1/CARD9 provided important support for the idea that LRRK2 acts as component of the SYK signaling pathway. In studies more specifically addressing how LRRK2 affects autophagy we found, somewhat to our surprise, that macrophages from LRRK2 transgenic mice upon stimulation of the dectin pathway exhibit decreased conversion of LC3 to LC3 II, the latter a molecule that appears at the distal end of the activated autophagy pathway. Complementary studies of macrophages from LRRK2-deficient mice showed that LRRK2 deficiency was associated with increased autophagy, thus confirming the result obtained with transgenic cells. In additional studies to address the issue of the molecular mechanism of LRRK2-mediated autophagy inhibition we showed that LRRK2 interacts with the autophagy initiator, beclin, and such interaction is associatd with breakdown of beclin dimers. Beclin breakdown may be mediated by caspase8 since LRRK2 also interacts with caspase8 and the latter is component of the BCL10 signaling complex mentioned above. Recent studies from other laboratories have shown that autophaphy leads to inhibition of activation and also to disturbances in IL-1beta signaling. The present studies therefore suggest that one of the mechanisms by which LRRK2 polymorphisms contribute to the inflammation of Crohn's disease is that these polymorphisms result in autophagy-related defects in the normal regulation of pro-inflammatory inflammasome/IL-1beta secretiion.