Chemogenetic Ablation of Dopaminergic Neurons in the Brain of Larval and Adult Zebrafish (Danio Rerio): Phenotypes and Regenerative Ability

Abstract

Dopamine exerts an important role in the regulation of motor activity in humans. During the progression of Parkinson’s disease, patients are faced with the progressive neurodegeneration of nigro-striatal dopamine neurons resulting in an array of pathological symptoms characteristic of the disease. Current treatment relies on targeting symptomatic aspects of the disease but currently Parkinson’s disease is incurable. Targeting the regeneration of DA neurons in PD patients could offer an alternative therapeutic approach that could stall and perhaps even revert the progression of the disease and improve the quality of life for patients. Here, I describe the generation of a transgenic zebrafish line for the non-invasive, conditional and specific ablation of dopaminergic neurons in both larval and adult zebrafish. Understanding the endogenous regenerative ability of the zebrafish may in the future contribute to the development of novel therapeutic approaches targeting DA neuron regeneration in humans. The Tg(dat:CFP-NTR) line efficiently labels and ablates most clusters of DA neurons in both the larval and the adult zebrafish brain. Neuronal ablation is followed by a locomotor and tail bend phenotype as well as by an increase in exploratory behavior. Using double transgenic larvae, we showed through live imaging that loss of DA neurons induces an increase in nestin expression; in addition we show an increase in the number of proliferating cells and an up regulation of genes involved in neurogenesis and tissue repair. Adult zebrafish were able to fully recover their DA neuronal population in the olfactory bulb within 45 days post ablation. Overall the Tg(dat:CFP-NTR) zebrafish offers a novel tool for the study of the molecular and cellular mechanisms driving the regeneration of DA neurons in the zebrafish brain and will be a useful tool for the field of regenerative medicine.