HDAC5 and Parkinson disease: Emerging evidence has revealed that epigenetic perturbation is an important contributor to PD, positioning it as a promising target for potential therapeutic interventions.286,314 For example, HDAC5 inhibition is effective in attenuating microglial activation and PD-related pathologies in 6-hydroxydopamine (6-OHDA)-lesioned rats.315 On the other hand, the activation of GPCRs has been demonstrated to exhibit neuroprotective properties in PD mouse models.