Objective: To replicate the previous study of Alcalay and coauthors on estimation of lysosomal enzymes activities [1] with additional estimation of corresponding substrates in patients with LRRK2 G2019S associated Parkinson’s disease (LRRK2-G2019S-PD).

Background: G2019S mutation in leucine-rich repeat kinase 2 (LRRK2) is common genetic risk factor for Parkinson’s disease (PD). LRRK2-G2019S-PD molecular mechanisms remain unknown. G2019S LRRK2 mutation was associated with activity of glucoceresobridase (GCase), encoded by the GBA gene, mutations in which are also common genetic risk factors for PD [2]. Previously, Alcalay and coauthors showed that LRRK2-G2019S-PD patients had higher GCase, acid sphingomyelinase (ASM) and alphagalactosidase A (GLA) activities than patients with sporadic form of PD (sPD) [1]. Substrate concentrations of lysosomal enzymes were not previously evaluated.

Method: LRRK2 G2019S mutation screening was conducted in spread cohort of PD patients (N=1260) as described previous [3]. 132 sPD patients, 18 patients with PD, associated with mutations in the GBA gene (GBA-PD) and 166 controls were enrolled to asses enzyme activities (GCase, GLA, ASM) and their substrates concentrations (hexosylsphingosine (HexSph), globotriaosylsphingosine (LysoGb3), lysosphingomyelin (LysoSM)) by liquid chromatography with tandem mass spectrometry in dry blood spots.

Results: 18 LRRK2 G2019S heterozygous mutation were identified among PD patients, meanwhile none was found in controls. The adjusted frequency of LRRK2 G2019S mutation for North-West region of Russia was 1.4% in PD patients than shown in our previous study [4]. GALC activity was elevated in sPD compared to controls (p=0.0051). GBA-PD was characterized by lower ASM activity than sPD (p=0.0016) and, as expected, by lower GCase activity than sPD and controls (p<0.001). Interestingly, GCase activity was elevated in LRRK2-G2019S-PD compared to GBA-PD (p=0.004), while HexSph concentration was increased in LRRK2-G2019S-PD compared to sPD (p=0.039). LysoSM concentration was decreased in sPD compared to controls (p=0.00023). LysoGb3 concentration was increased in LRRK2-G2019S-PD compared to sPD, GBA-PD, controls (p<0.05).

Conclusion: In our study we did not show an increase of GCase and GLA activities, but instead revealed an accumulation of their substrates (HexSph, LysoGb3) in LRRK2-G2019S-PD. The study was supported by RSF grant №22-25-00501

References: 1. Alcalay RN, Wolf P, Levy OA, et al. Alpha galactosidase A activity in Parkinson’s disease. Neurobiol Dis. 2018;112:85-90. doi:10.1016/j.nbd.2018.01.012
2. Ysselstein, D., Nguyen, M., Young, T. J., Severino, A., Schwake, M., Merchant, K., & Krainc, D. (2019). LRRK2 kinase activity regulates lysosomal glucocerebrosidase in neurons derived from Parkinson’s disease patients. Nature communications, 10(1), 5570. https://doi.org/10.1038/s41467-019-13413-w
3. Hashad, D.I., Abou-Zeid, A.A., Achmawy, G.A., Allah, H.M., Saad, M.A., 2011. G2019S mutation of the leucine-rich repeat kinase 2 gene in a cohort of Egyptian patients with Parkinson’s disease. Genet Test Mol Biomarkers 15, 861–866. https://doi.org/10.1089/gtmb.2011.0016
4. Emelyanov, A. K., Usenko, T. S., Tesson, C., Senkevich, K. A., Nikolaev, M. A., Miliukhina, I. V., … & Pchelina, S. N. (2018). Mutation analysis of Parkinson’s disease genes in a Russian data set. Neurobiology of Aging, 71, 267-e7.

« Back to 2022 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/profiling-the-biochemical-lysosomal-activities-in-blood-of-patients-with-lrrk2-g2019s-associated-parkinsons-disease/