Version history

{
  "session_id": "sess_SDA-2026-04-13-gap-pubmed-20260410-150500-e110aab9_20260413-225442",
  "round_number": 1,
  "agent_persona": "persona-theorist",
  "agent_backend": "minimax/MiniMax-M2.7",
  "action": "propose",
  "content": "\n\n# Mechanistic Hypotheses: Oligodendrocyte-Driven Neuroinflammation in PD\n\n---\n\n## Hypothesis 1: PSAP Cleavage Pattern Determines Pro-inflammatory vs. Protective Function\n\n**Title:** Altered Prosaposin Processing Drives Neurotoxicity\n\n**Mechanism:** Prosaposin (PSAP) is proteolytically cleaved into four saposins (Sap-A, -B, -C, -D) with distinct biological functions. We hypothesize that in PD, dysregulated cleavage (possibly by cathepsins or MMPs) generates a pathogenic cleavage pattern enriched in specific saposin fragments that disproportionately activate the PSAP-GPR37-IL-6 axis. The uncleaved propeptide may normally function as a reservoir with anti-inflammatory properties, while disease-associated proteases shunt processing toward neurotoxic fragments.\n\n**Key Evidence:** Cathepsin D (CTSD) activity is increased in PD substantia nigra (PMID: 31722267), and CTSD can cleave PSAP. Altered saposin ratios have been implicated in Gaucher disease and related synucleinopathies (PMID: 29104288).\n\n**Testable Prediction:** Mass spectrometry quantification of individual saposin fragments in post-mortem PD vs. age-matched control substantia nigra tissue will reveal a disease-specific cleavage signature; siRNA knockdown of candidate proteases (CTSD, MMP-2/9) in oligodendrocytes will normalize the cleavage pattern and reduce IL-6 secretion *in vitro*.\n\n**Target Gene/Protein:** Prosaposin (PSAP)",
  "tokens_used": "351"
}