Elevated LRRK2 autophosphorylation in brain-derived and peripheral exosomes in LRRK2 mutation carriers
Authors: Tyler Maltbie
Tao Ye
Shijie Wang
Andrew B West
Omar S Mabrouk
Jan Aasly
Zhiyong Liu
Journal: Acta Neuropathologica Communications (2017)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: Biomarkers; Microvesicles; Movement Disorders; Neurodegeneration; Park8
Affiliations: Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, 35233, USA., Biogen, Discovery and Early Development Biomarkers, Cambridge, MA, 02142, USA., Dept of Neurology, Dept of Neuroscience, St. Olavs Hospital, Norwegian University of Science and Technology, 7030, Trondheim, Norway. ., Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, 35233, USA. .

Abstract:  Missense mutations in the leucine-rich repeat kinase 2 (LRRK2) gene can cause late-onset Parkinson disease (PD). LRRK2 mutations increase LRRK2 kinase activities that may increase levels of LRRK2 autophosphorylation at serine 1292 (pS1292) and neurotoxicity in model systems. pS1292-LRRK2 protein can be packaged into exosomes and measured in biobanked urine. Herein we provide evidence that pS1292-LRRK2 protein is robustly expressed in cerebral spinal fluid (CSF) exosomes. In a novel cohort of Norwegian subjects with and without the G2019S-LRRK2 mutation, with and without PD, we quantified levels of pS1292-LRRK2, total LRRK2, and other exosome proteins in urine from 132 subjects and in CSF from 82 subjects. CSF and urine were collected from the same morning clinic visit in 55 of the participants. We found that total LRRK2 protein concentration was similar in exosomes purified from either CSF or urine but the levels did not correlate. pS1292-LRRK2 levels were higher in urinary exosomes from male and female subjects with a LRRK2 mutation. Male LRRK2 mutation carriers without PD had intermediate pS1292-LRRK2 levels compared to male carriers with PD and controls. However, female LRRK2 mutation carriers without PD had the same pS1292-LRRK2 levels compared to female carriers with PD. pS1292-LRRK2 levels in CSF exosomes were near saturated in most subjects, ten-fold higher on average than pS1292-LRRK2 levels in urinary exosomes, irrespective of LRRK2 mutation status or PD diagnosis. These results provide insights into the effects of LRRK2 mutations in both the periphery and brain in a well-characterized clinical population and show that LRRK2 protein in brain exosomes may be much more active than in the periphery in most subjects. 

Retracted: No

PubPeer comments:
 I may be mistaken, but there seem to be some markings around portions of the pS935-LRRK2 band in Figure 1A that may indicate a splice. Could the authors please post the original data? *** False color ![file] *** Inverse ![file] *** Original ![file] , 
 In this study, several biological fluids are ultracentrifuged, and the pelleted material is investigated and labeled  exosomes. However, no characterization is done to check the purity of these particles compared with other extracellular vesicles and other pelleted particles. It is likely that some exosomes have been pelleted, but it cannot be ruled out that they are a small minority and may not contribute importantly to the results. , 
 #1 Hello, My name is Dr. Zhiyong Liu and I was recently made aware of this post regarding some of the data I generated for this past study. I understand that the email addresses that are listed for the two last authors of this paper are not correct and should have returned as invalid addresses that no longer exist. Regarding the pS935-LRRK2 blot indicated below, the original blue-film was scanned at fairly low resolution directly to a JPEG where the artifacts probably occurred (in compression). Nevertheless the original images we have posted correspond closely to the images represented in the posted PDF of the article. The image is not spliced in any way. The pS935-LRRK2 blots were not part of any type of quantification in the study, hence only low resolution JPEGs were obtained. We have since switched to a more modern higher resolution digital ChemiDoc system and have not used film or JPEG compression in many years. ![file] Sincerely, Zhiyong ,