Neurodegenerative Disease Mechanisms in Parkinson's Disease

Parkinson’s disease is typified by the progressive loss of dopaminergic neurons in the substantia nigra and widespread deposition of misfolded α-synuclein into Lewy bodies. Pathogenic α-synuclein species accumulate in vulnerable regions before propagating along neural networks in a prion-like manner, driving neuronal dysfunction and cell death. Multiple converging mechanisms—including mitochondrial impairment, oxidative stress, defective autophagy, neuroinflammation and calcium dysregulation—amplify this process. Emerging frameworks distinguish a brain-first phenotype, where pathology arises centrally (for example in the olfactory bulb or amygdala), from a body-first phenotype, in which aggregates originate in the enteric or peripheral autonomic nervous system and ascend via vagal or sympathetic routes. This dichotomy underpins heterogeneity in clinical progression, non-motor manifestations and therapeutic responses. Regional susceptibility is further shaped by gene expression profiles and the composition of local cell populations. Advances in imaging and biomarker detection—ranging from dopaminergic PET scans to network-based atrophy mapping and peripheral tissue assays—have enhanced early diagnosis. Therapeutic strategies now aim to inhibit α-synuclein aggregation, bolster proteostatic clearance, modulate immune activation and safeguard mitochondrial function. A comprehensive understanding of these intertwined molecular and network-level processes remains essential for the development of personalised, disease-modifying interventions.

Research from Nature Portfolio

Recent postmortem analyses in individuals prior to clinical diagnosis have delineated three preclinical patterns of Lewy pathology: a central brain-first route and two distinct peripheral body-first routes exhibiting either parasympathetic or sympathetic predominance. This work refines the model of initial α-synuclein origin and early organ involvement, offering new insight into subtype-specific progression. Concurrently, longitudinal MRI studies have demonstrated that cortical thinning in early Parkinson’s disease correlates with both structural and functional connectivity to a midbrain “disease reservoir.” Regions more strongly connected to this reservoir show accelerated atrophy over one year, providing empirical support for the network-spread hypothesis of neurodegeneration and identifying cortical regions that may presage cognitive decline.

Neurodegenerative Disease Mechanisms in Parkinson's Disease publication trend

The graph below shows the total number of articles in neurodegenerative disease mechanisms in parkinson's disease across all publications each year (not limited to Nature Index journals).

Technical terms

α-synuclein aggregation: The misfolding and accumulation of α-synuclein proteins into insoluble oligomers and fibrils.

Lewy bodies: Intracellular inclusions composed primarily of aggregated α-synuclein found in affected neurons.

Prion-like propagation: A mechanism by which misfolded proteins template further misfolding and spread via neural connections.

Connectome: The comprehensive map of structural or functional neural pathways in the brain.

Brain-first and body-first subtypes: Proposed phenotypes where pathology initiates centrally within the brain or peripherally within the autonomic nervous system, respectively.

Rapid eye movement sleep behaviour disorder (RBD): A prodromal symptom characterised by enactment of vivid dreams, indicative of early autonomic nervous system involvement.

Autonomic nervous system: The network controlling involuntary bodily functions, comprising sympathetic and parasympathetic branches.

Cortical thinning: The reduction of grey matter thickness measured by MRI as a marker of neurodegeneration.

References

1. Local vulnerability and global connectivity jointly shape neurodegenerative disease propagation. PLOS Biology (2019).
2. Sympathetic and parasympathetic subtypes of body-first Lewy body disease observed in postmortem tissue from prediagnostic individuals. Nature Neuroscience (2025).
3. Network connectivity determines cortical thinning in early Parkinson’s disease progression. Nature Communications (2018).
4. Disease progression in proposed brain-first and body-first Parkinson’s disease subtypes. npj Parkinson's Disease (2024).
5. Brain-first vs. body-first Parkinson's disease: An update on recent evidence. Parkinsonism & Related Disorders (2024).
6. A postmortem study suggests a revision of the dual-hit hypothesis of Parkinson’s disease. npj Parkinson's Disease (2022).