High molecular weight insoluble parkin in the substantia nigra of patients with idiopathic Parkinson’s disease
Bibliographic record
Abstract
Parkinson's disease (PD) is characterized by a loss of dopaminergic neurons and accumulation of α-synuclein (α-syn)-containing Lewy bodies in the substantia nigra (SN) pars compacta. Mutations in the gene coding for the protein parkin cause a form of autosomal recessive juvenile parkinsonism, but its role in idiopathic PD is poorly understood. Here, to investigate parkin changes in the SN in PD, we established a clinicopathology research platform comparing PD patients (n = 24) with Controls (n = 21). We first confirmed the massive loss of dopamine (DA) levels (-96%) in the putamen of PD patients, using HPLC/electrochemistry. Higher levels of phosphorylated α-syn (αsynP129) (23-fold) were observed in the SN of PD patients by Western immunoblotting. In formic acid extracts, an increase in the insoluble oligomeric form of parkin migrating at 260 kDa was observed (+ 49%) in the SN of PD patients, along with lower levels of the 55 kDa monomeric form (-47%). These changes in parkin were specific for the SN, and not observed in the putamen, parietal cortex and cerebellum. High molecular weight parkin correlated with αsynP129 levels and dopamine loss and was more prominently found in PD patients with levodopa-induced dyskinesias. Additional studies in animal models suggest that the aggregation of parkin is not a direct consequence of dopaminergic depletion or αsyn overproduction, but a component of PD cellular pathophysiology. Taken together, the results reported herein show that, beside dopamine loss and increased αsynP129, neurodegeneration in idiopathic PD is associated with a conversion of parkin into an insoluble high molecular weight form in the SN.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".