TRPV4 and Parkinson disease: However, an in vivo study in a mouse MPTP model of PD revealed that adeno-associated virus (AAV)-induced TRPV4 knockdown alleviated movement deficits and nigral neurodegeneration in PD mice, whereas the upregulation of TRPV4 via the injection of a constructed AAV-TRPV4, aggravated it [149].