PT  - JOURNAL ARTICLE
AU  - Vibeke Devold Valderhaug
AU  - Ola Huse Ramstad
AU  - Rosanne van de Wijdeven
AU  - Kristine Heiney
AU  - Stefano Nichele
AU  - Axel Sandvig
AU  - Ioanna Sandvig
TI  - Structural and functional alterations associated with the LRRK2 G2019S mutation revealed in structured human neural networks
AID  - 10.1101/2020.05.02.073726
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.05.02.073726
4099  - http://biorxiv.org/content/early/2020/05/02/2020.05.02.073726.short
4100  - http://biorxiv.org/content/early/2020/05/02/2020.05.02.073726.full
AB  - Mutations in the LRRK2 gene have been widely linked to Parkinson’s disease. The G2019S variant has been shown to contribute uniquely to both familial and sporadic forms of the disease. LRRK2-related mutations have been extensively studied, yet the wide variety of cellular and network events directly or indirectly related to these mutations remain poorly understood. In this study, we structured multi-nodal human neural networks carrying the G2019S mutation using custom-designed microfluidic chips coupled to microelectrode-arrays. By applying live imaging approaches, immunocytochemistry and computational modelling, we have revealed alterations in both the structure and function of the resulting neural networks when compared to controls. We provide first evidence of increased neuritic density associated with the G2019S LRRK2 mutation, while previous studies have found either a strong decrease, or no change, compared to controls. Additionally, we corroborate previous findings regarding increased baseline network activity compared to control neural networks. Furthermore, we can reveal additional network alterations attributable to the specific mutation by selectively inducing transient overexcitation to confined parts of the structured multi-nodal networks. These alterations, which we were able to capture both at the micro- and mesoscale manifested as differences in relative network activity and correlation, as well as in mitochondria activation, neuritic remodelling, and synaptic alterations. Our study thus provides important new insights into early signs of neural network pathology significantly expanding upon the current knowledge relating to the G2019S Parkinson’s disease mutation.Competing Interest StatementThe authors have declared no competing interest.AbbreviationsCamKIIcalmodulin-dependent protein kinase IIiPSCinduced pluripotent stem cellKAkainic acidLRRK2leucine-rich repeat kinase 2MEAmicroelectrode arrayMFRmean firing rateNGSnormal goat serumNSCneural stem cellPBSphosphate buffered salinePCAprincipal component analysisPDParkinson’s diseasePDMSpolydimethylsiloxanePFAparaformaldehydePLOpoly-L-ornithinePSDpost-synaptic densityROSreactive oxygen speciesRTroom temperatureTMRMtetramethylrhodiamine