RESUMEN
The motor symptoms of Parkinson's disease (PD) are thought to stem from an imbalance in the activity of striatal direct- and indirect-pathway spiny projection neurons (SPNs). Disease-induced alterations in the activity of networks controlling SPNs could contribute to this imbalance. One of these networks is anchored by the parafascicular nucleus (PFn) of the thalamus. To determine the role of the PFn in striatal PD pathophysiology, optogenetic, chemogenetic, and electrophysiological tools were used in ex vivo slices from transgenic mice with region-specific Cre recombinase expression. These studies revealed that in parkinsonian mice, the functional connectivity of PFn neurons with indirect pathway SPNs (iSPNs) was selectively enhanced by cholinergic interneurons acting through presynaptic nicotinic acetylcholine receptors (nAChRs) on PFn terminals. Attenuating this network adaptation by chemogenetic or genetic strategies alleviated motor-learning deficits in parkinsonian mice, pointing to a potential new therapeutic strategy for PD patients.
Asunto(s)
Neuronas Colinérgicas/fisiología , Cuerpo Estriado/fisiopatología , Potenciales Postsinápticos Excitadores , Interneuronas/fisiología , Enfermedad de Parkinson/fisiopatología , Tálamo/fisiopatología , Animales , Neuronas Colinérgicas/metabolismo , Cuerpo Estriado/citología , Ácido Glutámico/metabolismo , Interneuronas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Enfermedad de Parkinson/metabolismo , Receptores Nicotínicos/metabolismo , Tálamo/citologíaRESUMEN
Highly topographic organization of neural circuits exists for the regulation of various brain functions in corticobasal ganglia circuits. Although neural circuit-specific refinement during synapse development is essential for the execution of particular neural functions, the molecular and cellular mechanisms for synapse refinement are largely unknown. Here, we show that protocadherin 17 (PCDH17), one of the nonclustered δ2-protocadherin family members, is enriched along corticobasal ganglia synapses in a zone-specific manner during synaptogenesis and regulates presynaptic assembly in these synapses. PCDH17 deficiency in mice causes facilitated presynaptic vesicle accumulation and enhanced synaptic transmission efficacy in corticobasal ganglia circuits. Furthermore, PCDH17(-/-) mice exhibit antidepressant-like phenotypes that are known to be regulated by corticobasal ganglia circuits. Our findings demonstrate a critical role for PCDH17 in the synaptic development of specific corticobasal ganglia circuits and suggest the involvement of PCDH17 in such circuits in depressive behaviors.