GTPase function of Leucine rich repeat kinase 2

目前，我们发现PD相关的非编码变异对LRRK2表达的影响是通过小胶质细胞特异性地传播的，而不是通过人脑中表达LRRK2的其他类型的细胞。我们在人类额叶皮质和黑质中发现了调节LRRK2表达的小胶质细胞特异性染色质区域，并在人类诱导的多能干细胞来源的小胶质细胞模型中证实了这些结果。我们使用大规模簇状规则间隔短回文重复序列干扰(CRISPRi)筛选表明，包含单核苷酸变体rs6581593的调节DNA元件影响小胶质细胞中LRRK2的表达。我们的研究表明，在评估非编码变异在疾病发病机制中的作用时，应考虑细胞类型，并揭示了LRRK2 5‘区与帕金森病风险相关的机制。该实验室正在进行的工作旨在将这些观察扩展到与帕金森氏症相关的其他基因，并在更大的队列中进行复制。 我们还与NCI的张平的实验室合作，使用冷冻-EM方法研究了相关激酶LRRK1的结构。我们使用溶酶体磷酸化的RAB7作为读数，从结构分析中证实了旨在影响LRRK1活性的突变在细胞中产生LRRK1活性的变化是有效的。

In the current period, we found that the influence of PD-associated noncoding variation on LRRK2 expression is specifically propagated through microglia and not by other cell types that express LRRK2 in the human brain. We find microglia-specific regulatory chromatin regions that modulate the LRRK2 expression in human frontal cortex and substantia nigra and confirm these results in a human-induced pluripotent stem cell-derived microglia model. We showed, using a large-scale clustered regularly interspaced short palindromic repeats interference (CRISPRi) screen, that a regulatory DNA element containing the single-nucleotide variant rs6581593 influences the LRRK2 expression in microglia. Our study demonstrates that cell type should be considered when evaluating the role of noncoding variation in disease pathogenesis and sheds light on the mechanism underlying the association of the 5' region of LRRK2 with PD risk. Ongoing work in the lab is aimed at extending these observations to other genes associated with Parkinson's disease and replication in larger cohorts. We have also collaborated with the laboratory of Ping Zhang at NCI to look at the structure of the related kinase LRRK1 using cryo-EM approaches. We were able to confirm that mutations designed to affect LRRK1 activity from structural analyses were effective at producing changes in LRRK1 activity in cells, using lysosomal phosphorylated RAB7 as a readout.