Loss of Panx1 Function in Zebrafish Alters Motor Behavior in a Lab-on-Chip Model of Parkinson's Disease

Abstract

Pannexin 1 (Panx1) forms ATP-permeable membrane channels that play essential roles in purinergic signaling in the nervous system. Several studies suggest a link between Panx1-based channels activity and neurodegenerative disorders including Parkinson’s disease (PD), but experimental evidence is limited. Here, we applied behavioral and molecular screening of zebrafish larvae to examine the role of Panx1 in both pathological and normal conditions, using electrical stimulation in a microfluidic chip and RT-qPCR. A zebrafish model of PD was produced by exposing wildtype (panx1a+/+) and Panx1a knock-out (panx1a-/-) zebrafish larvae to 250µM 6-hydroxydopamine (6-OHDA). After 72hrs treatment with 6-OHDA a reduced electric-induced locomotor activity was observed in 5 days post fertilization (dpf) panx1a+/+ larvae. The 5dpf panx1a-/- larvae were not different from affected. The RT-qPCR data showed a reduction in tyrosine hydroxylase (TH) expression level in both panx1a+/+ and panx1a-/- groups. However, TH expression of 6-OHDA exposed panx1a-/- larvae was not decreased when compared to untreated mutants. Extending 6-OHDA treatment duration to 120hrs caused a significant reduction in the locomotor response of 7dpf panx1a-/- larvae when compared to the untreated panx1a-/- group. The RT-qPCR data also confirmed a significant decrease in TH expression levels after 120hrs treatments with 6-OHDA for both genotypes. Our results suggest that the absence of Panx1a channels compromised dopaminergic signaling in 6-OHDA-treated zebrafish larvae. We here propose that zebrafish Panx1a models offer great opportunities to shed light on the physiological and molecular basis of PD. Panx1a might play a preventive role on PD progression, and therefore deserves further investigation