Neuroinflammation and Parkinson’s disease - from neurodegeneration to therapeutic opportunities

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder worldwide. Clinically, it is characterized by a progressive degeneration of dopaminergic neurons (DAn), resulting in severe motor complications. Preclinical and clinical studies have indicated that neuroinflammation can play a role in PD pathophysiology, being associated with its onset and progression. Nevertheless, several key points concerning the neuroinflammatory process in PD remain to be answered. Bearing this in mind, in the present review, we cover the impact of neuroinflammation on PD by exploring the role of inflammatory cells (i.e., microglia and astrocytes) and the interconnections between the brain and the peripheral system. Furthermore, we discuss both the innate and adaptive immune responses regarding PD pathology and explore the gut–brain axis communication and its influence on the progression of the disease.The present work was supported by Prémios Santa Casa Neurociências— Prize Mantero Belard for Neurodegenerative Diseases Research (MB-28-2019), the Portuguese Foundation for Science and Technology (FCT) to S.M. (CEECIND/01902/2017) and F.G.T. (2021.00643.CEECIND), the European Regional Development Fund (FEDER), the Competitiveness Internationalization Operational Programme (POCI), national funds through the Foundation for Science and Technology (FCT), under the scope of projects UIDB/50026/2020, UIDP/50026/2020, POCI-01-0145-FEDER-029751, and EXPL/MED-PAT/0931/2021, project NORTE-01-0145-FEDER-000023, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), and under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER)