LRRK2 modulates the progression of neuropathology in a mouse model of tauopathy

描述（由申请人提供）：tau（一种功能受磷酸化调节的微管结合蛋白）与帕金森病（PD）发病机制之间的联系尚不清楚。有鉴于此，有趣的是，编码富含亮氨酸重复序列激酶2（LRRK 2）的基因中的突变（其是PD的主要风险因素）与包括tau缠结和异常tau磷酸化的病理学相关。最常见的突变G2019 S位于LRRK 2的激酶结构域内，并在体外显示出增加的激酶活性，这被认为是介导其细胞毒性的原因。LRRK 2的正常功能 以及突变如何影响该功能以影响疾病发病机制尚不清楚。Tau最近已被证明被LRRK 2磷酸化，但仍不知道LRRK 2和Tau是否在体内相互作用以及这种相互作用如何被LRRK 2中的突变改变以影响聚集并引起疾病。本申请的总体目标是确定LRRK 2是否调节tau病理并鉴定其发生的机制。该提案将使用体外和体内方法的组合来确定野生型（WT）和突变型LRRK 2改变tau磷酸化和聚集的机制，并确定这如何影响神经毒性。目标1下的实验将确定在体外和细胞培养系统中WT和突变体LRRK 2如何改变tau磷酸化和聚集。初步数据已经证实，tau蛋白是LRRK 2激酶活性的良好底物，并且已经鉴定了在体外被tau蛋白磷酸化的多个位点。在这些位点的LRRK 2磷酸化对tau聚集体形成的影响将使用体外和培养细胞中的tau包涵体形成来检查。目标1中生成的数据的生物学相关性将通过本提案目标2下的研究进行测试，该研究将确定WT和突变型LRRK 2如何调节新型小鼠模型中的tau蛋白病。WT和G2019 S LRRK 2小鼠将与tau蛋白病的rTg 4510小鼠模型杂交，所述rTg 4510小鼠模型具有良好表征的tau蛋白病病程。将在来自这些小鼠的组织中测量Tau磷酸化、聚集和神经毒性。初步数据显示，WT LRRK 2/rTg 4510增加了特定位点的tau磷酸化，并增加了tau聚集，支持在该提议中使用这些模型。这些研究的结果对于理解PD病因和指导未来的研究以确定LRRK 2介导的tau发病机制至关重要。

DESCRIPTION (provided by applicant): The link between tau, a microtubule binding protein whose function is regulated by phosphorylation, and the pathogenesis of Parkinson's disease (PD) remains unclear. In view of this, it is interesting that mutations in the gene encoding Leucine-rich repeat kinase 2 (LRRK2), which are a major risk factor for PD, have been associated with pathologies that include tau tangles and aberrant tau phosphorylation. The most common mutation, G2019S, is within the kinase domain of LRRK2 and shows increased kinase activity in vitro, which is proposed to mediate its cellular toxicity. The normal function of LRRK2 and how mutations affect this function to affect disease pathogenesis is unknown. Tau has recently been shown to be phosphorylated by LRRK2, but it is still not known if LRRK2 and tau interact in vivo and how this interaction is altered by mutations in LRRK2 to affect aggregation and cause disease. The overall objectives of this application are to determine if LRRK2 modulates tau pathology and to identify the mechanism(s) by which this occurs. This proposal will use a combination of in vitro and in vivo approaches to identify mechanisms by which tau phosphorylation and aggregation are altered by wild-type (WT) and mutant LRRK2 and determine how this affects neurotoxicity. Experiments under Aim 1 will determine how tau phosphorylation and aggregation are altered by WT and mutant LRRK2 in vitro and in cell culture systems. Preliminary data has confirmed that tau is a good substrate for LRRK2 kinase activity and has identified multiple sites that are phosphorylated by tau in vitro. The effects of LRRK2 phosphorylation at these sites on the development of tau aggregates will be examined using tau inclusion formation in vitro and in cultured cells. The biological relevance of data generated in Aim 1 will be tested by studies under Aim 2 of this proposal that will determine how WT and mutant LRRK2 modulate tauopathy in novel mouse models. WT and G2019S LRRK2 mice will be crossed with the rTg4510 mouse model of tauopathy, which has a well-characterized disease course of tauopathy. Tau phosphorylation, aggregation and neurotoxicity will be measured in tissue from these mice. Preliminary data show that WT LRRK2/rTg4510 have increased tau phosphorylation at specific sites and increased tau aggregation, supporting the use of these models in this proposal. Results from these studies are essential to understanding PD etiology and directing future research to identify mechanisms of LRRK2-mediated tau pathogenesis.