Remote control of induced dopaminergic neurons in parkinsonian rats

Abstract

Direct lineage reprogramming through genetic-based strategies enables the conversion of differentiated somatic cells into functional neurons and distinct neuronal subtypes. Induced dopaminergic (iDA) neurons can be generated by direct conversion of skin fibroblasts; however, their in vivo phenotypic and functional properties remain incompletely understood, leaving their impact on Parkinson's disease (PD) cell therapy and modeling uncertain. Here, we determined that iDA neurons retain a transgene-independent stable phenotype in culture and in animal models. Furthermore, transplanted iDA neurons functionally integrated into host neuronal tissue, exhibiting electrically excitable membranes, synaptic currents, dopamine release, and substantial reduction of motor symptoms in a PD animal model. Neuronal cell replacement approaches will benefit from a system that allows the activity of transplanted neurons to be controlled remotely and enables modulation depending on the physiological needs of the recipient; therefore, we adapted a DREADD (designer receptor exclusively activated by designer drug) technology for remote and real-time control of grafted iDA neuronal activity in living animals. Remote DREADD-dependent iDA neuron activation markedly enhanced the beneficial effects in transplanted PD animals. These data suggest that iDA neurons have therapeutic potential as a cell replacement approach for PD and highlight the applicability of pharmacogenetics for enhancing cellular signaling in reprogrammed cell-based approaches.

How to make a midbrain dopaminergic neuron

“…via microRNAs and small molecules) regulate the activity of lineage-specific transcription factors that reassign cell fate (Ladewig et al, 2013). To date, numerous somatic cell types have been generated via direct reprogramming, including induced DA (iDA) neurons that have been used for transplantation (Caiazzo et al, 2011;Dell'Anno et al, 2014;Kim et al, 2011;Liu et al, 2012b;Pfisterer et al, 2011;Torper et al, 2013) (Fig. 4D,E).…”

Selective Manipulation of Neural Circuits

“…These tools have been applied to animal models of various neurological diseases. For Parkinson's disease [191,192], the goal has been to modulate the basal ganglia circuits in a way that is achieved with deep brain stimulation but with better spatial and temporal control. For stroke [193], excitatory optogenetics has been used to strengthen the function of intact circuits so that they can restore lost motor function.…”

Direct neuronal reprogramming: learning from and for development

“…The molecular logic behind the different transcription factor combinations for reprogramming is such that factors active at different stages of specification and differentiation are usually combined. As mentioned above, Ascl1, Lmx1a and Nurr1 are active at different stages in the dopaminergic lineage and together can reprogramme fibroblasts into dopamine-releasing neurons (Caiazzo et al, 2011;Dell'Anno et al, 2014). However, none of these studies has been able to generate dopaminergic neurons belonging to the specific A8-10 clusters (Hegarty et al, 2013).…”