Version history

{
  "session_id": "sess_SDA-2026-04-08-gap-pubmed-20260406-062128-afe67892_task_9aae8fc5",
  "round_number": 1,
  "agent_persona": "persona-theorist",
  "agent_backend": "scidex.core.llm.complete",
  "action": "propose",
  "content": "# Mechanistic Hypotheses: NF-κB–Complement Cascade Link in Sevoflurane-Induced Neuroinflammation\n\n## Hypothesis 1: Direct NF-κB Transcriptional Regulation of C1q Genes\n\n**Mechanism:** NF-κB (p65/p50 heterodimer) directly binds to κB sites in the promoters of complement component genes (C1QA, C1QB, C1QC), driving their transcription in microglia and astrocytes following sevoflurane exposure.\n\n**Target:** RELA (p65) subunit of NF-κB → C1QA/C1QB/C1QC transcriptional activation\n\n**Supporting evidence:**\n- NF-κB consensus binding sequences identified in human and mouse C1QA promoter regions\n- TNF-α–induced C1q expression in astrocytes is NF-κB–dependent (PMID: 25620734)\n- Sevoflurane activates NF-κB via ROS-mediated IKK activation (PMID: 31337481)\n\n**Predicted experiment:** ChIP-qPCR for p65 binding to C1QA promoter in primary microglia after 4% sevoflurane (2h); luciferase reporter assay with mutant κB sites\n\n**Confidence: 0.72**\n\n---\n\n## Hypothesis 2: Astrocyte IL-1β as Paracrine Mediator of Complement Expression\n\n**Mechanism:** Sevoflurane-activated NF-κB in astrocytes induces IL-1β secretion, which acts on microglial IL-1R1 to amplify complement C1q and C3 expression via autocrine signaling.\n\n**Target:** Astrocyte NF-κB → IL-1β secretion → Microglial IL-1R1/MyD88 → C1qa/C3 upregulation\n\n**Supporting evidence:**\n- IL-1β upregulates C3 in brain cells via NF-κB (PMID: 10899056)\n- Astrocyte-microglia crosstalk mediated by IL-1β in neuroinflammation (PMID: 30102911)\n- Sevoflurane elevates IL-1β in hippocampus (PMID: 32716529)\n\n**Predicted experiment:** Conditional deletion of NF-κB (IKKβ) in GFAP+ astrocytes using GFAP-Cre; measure IL-1β (Luminex) and microglial C1q/C3 (RNAscope+flow cytometry) after prolonged sevoflurane\n\n**Confidence: 0.68**\n\n---\n\n## Hypothesis 3: Microglial Priming via NF-κB–Dependent Complement Biosynthesis\n\n**Mechanism:** NF-κB activation reprograms microglia toward a disease-associated microglia (DAM) or M1-like phenotype characterized by autonomous C1q and C3 production, enabling direct synaptic complement tagging.\n\n**Target:** Microglial NF-κB (IKK complex) → DAM signature genes + complement gene program → synaptic C1q deposition\n\n**Supporting evidence:**\n- DAM microglia upregulate complement genes (Trem2-independent cluster) (PMID: 28872028)\n- C1q localizes to synapses in an NF-κB–dependent manner in LPS models (PMID: 29980664)\n- Prolonged sevoflurane shifts microglia toward pro-inflammatory state (PMID: 36600274)\n\n**Predicted experiment:** scRNA-seq + C1q reporter (C1qa-Cre;Ai9) in CX3CR1-GFP mice after sevoflurane ± IKK inhibitor (ML120B); spatial transcriptomics to map C1q+ microglia-synapse proximity\n\n**Confidence: 0.65**\n\n---\n\n## Hypothesis 4: TNF-α–C1r/C1s Bridge Between NF-κB and Classical Complement Pathway\n\n**Mechanism:** NF-κB–induced TNF-α activates TNF receptor signaling in neurons/astrocytes, inducing C1r and C1s expression, which together with C1q initiates the proteolytic complement cascade targeting synapses.\n\n**Target:** NF-κB → TNF-α → TNFR1 → neuronal C1R/C1S expression → C1 complex formation\n\n**Supporting evidence:**\n- TNF-α potentiates complement synthesis in CNS (PMID: 15282354)\n- C1r/C1s can be induced by inflammatory cytokines (PMID: 25620734)\n- TNF-α/NF-κB axis implicated in sevoflurane neurotoxicity (PMID: 34512547)\n\n**Predicted experiment:** Neuron-astrocyte-microglia triple culture with TNF-α blockade (etanercept or anti-TNF-α) and sevoflurane; measure C1r/C1s by ELISA and complement cascade activation (C4a/iC4b)\n\n**Confidence: 0.58**\n\n---\n\n## Hypothesis 5: Circulating IL-6 Transactivates Hepatic Complement via STAT3–NF-κB Cooperativity\n\n**Mechanism:** Sevoflurane/NF-κB induces systemic IL-6, which drives hepatic C3 production via STAT3; circulating C3 enters the brain through disrupted BBB, where microglial NF-κB cleaves C3 to active C3b for synaptic opsonization.\n\n**Target:** NF-κB → IL-6 → STAT3 (liver) → Hepatic C3 → BBB breakdown → Microglial C3aR/C3bR → Synaptic pruning\n\n**Supporting evidence:**\n- Peripheral C3 contributes to neuroinflammation and synapse loss (PMID: 32187543)\n- IL-6 induces hepatic acute-phase response including complement (PMID: 2906214)\n- Sevoflurane increases serum IL-6 and BBB permeability",
  "tokens_used": "1060",
  "persona_id": "persona-theorist"
}