Biology subjects

Kadgien, C. A.

Publications and source records attributed to Kadgien, C. A..

2 recordsLinked to original sources

bioRxiv2024

Emergent glutamate & dopamine dysfunction in VPS35(D620N) knock-in mice and rapid reversal by LRRK2 inhibition

The D620N variant in Vacuolar Protein Sorting 35 (VPS35) causes autosomal-dominant, late- onset Parkinsons disease. VPS35 is a core subunit of the retromer complex that canonically recycles transmembrane cargo from sorting endosomes. Although retromer cargoes include many synaptic proteins, VPS35s neuronal functions are poorly understood. To investigate the consequences of the Parkinsons mutation, striatal neurotransmission was assessed in 1-, 3- & 6-month-old VPS35 D620N knock-in (VKI) mice. Spontaneous and optogenetically- evoked corticostriatal glutamate transmission was increased in VKI striatal spiny projection neurons by 6 months, when total striatal glutamate release, quantified by iGluSnFR imaging, showed similarities to wild-type. dLight imaging revealed robust increases in VKI striatal dopamine release by 6 months, which were reversed with acute ex vivo leucine-rich repeat kinase 2 (LRRK2) inhibition. We conclude that increased glutamate and dopamine transmission in VKI mice progressively emerges in young-adulthood, and that dopamine dysfunction is likely the result of sustained, rapidly-reversible, LRRK2 hyperactivity.

neuroscience↗

bioRxiv2021

Surface GluA1 and glutamate transmission are increased in VPS35 D620N neurons and altered by LRRK2 kinase inhibition

Vacuolar protein sorting 35 (VPS35) regulates receptor recycling from endosomes. A missense mutation in VPS35 (D620N) leads to autosomal-dominant, late-onset Parkinsons disease. Here, we use a VPS35 D620N knock-in mouse to study the neurobiology of this mutation. In brain tissue, we confirm previous findings that the mutation results in reduced binding of VPS35 with WASH-complex member FAM21, and robustly elevated phosphorylation of the LRRK2 kinase substrate Rab10. In cultured cortical neurons, the mutation results in increased endosomal recycling protein density (VPS35-FAM21 co-clusters and Rab11 clusters), glutamate release, and GluA1 surface expression. LRRK2 kinase inhibition exerted genotype-specific effects on GluA1 surface expression, but did not impact glutamate release phenotypes. These results improve our understanding of the early effects of the D620N mutation on cellular functions that are specific to neurons. These observations provide candidate pathophysiological pathways that may drive eventual transition to late-stage parkinsonism in VPS35 families, and support a synaptopathy model of neurodegeneration.

neuroscience↗