What question did this study set out to answer?

This study proposes a causal chain linking purinergic signaling, oxidative stress, and neuroinflammation in autism spectrum disorder (ASD).

June 20, 2026Open Access

A Unified Purinergic-Redox-Inflammasome Cascade in Autism Spectrum Disorder: Formalizing the eATP → SAHH → SAH → GSH → NLRP3 → NMDA Sequence as a Falsifiable Mechanistic Hypothesis

Key Points

This study proposes a causal chain linking purinergic signaling, oxidative stress, and neuroinflammation in autism spectrum disorder (ASD).
Systematic synthesis of 18+ studies involving over 52,000 participants.
Graded empirical support for five causal links based on existing data from multiple fields.
Developed a testable prediction for purinergic neutralization effects on biomarkers and behavior.
Chronic eATP elevation in ASD was confirmed with a 17-fold failure to reverse in typical development.
GSH depletion shown to correlate with SAH accumulation and NLRP3 activation, indicating oxidative stress involvement.
Purinergic neutralization predicted to sequentially normalize biomarkers and improve behavior without single-field model intervention.

Abstract

AbstractBackground: Autism spectrum disorder (ASD) research is fragmented across three non-communicating literatures: mitochondrial bioenergetics, redox biochemistry, and neuroinflammation. Each field identifies a distinct entry point into ASD pathophysiology without asking what precedes it. This structural isolation has produced robust but disconnected findings and a trail of heterogeneous clinical trials whose failure modes have not been mechanistically explained.Objective: We propose a five-link causal chain hypothesis — the Purinergic-Redox-Inflammasome (PRI) cascade — connecting chronic extracellular ATP (eATP) elevation through S-adenosylhomocysteine hydrolase (SAHH) inhibition, S-adenosylhomocysteine (SAH) accumulation, glutathione (GSH) depletion, and constitutive NLRP3 inflammasome activation to NMDA receptor dysfunction and behavioral phenotype in the CDR-active subtype of ASD. Each link has independent empirical support; the complete five-link sequence has never been tested as an integrated causal model in a single cohort.Methods: Systematic cross-field synthesis of 18+ anchor studies (cumulative n > 52,000) spanning GEO transcriptomics (GSE26415, GSE18123), SPARK Biobank genomic/phenotypic data (n > 50,000; searched for purinergic metabolomics but no published dataset found — see Limitations), KidsFirst (n = 6,951), and five meta-analyses. Evidence for each link was graded on a three-tier epistemic scale: (1) Demonstrated in human ASD data, (2) Mechanistically demonstrated in non-ASD systems, (3) Model-predicted. Every claim in this paper carries an explicit epistemic grade.Key findings — the five links: (1) Chronic eATP elevation in ASD: directly demonstrated by Naviaux et al. 2024 (n = 258; purine network connectivity reverses 17-fold in typical development, a reversal that fails to occur in ASD, across 50 biochemical pathways). MODEL-PREDICTEDThat this elevation is also detectable via SPARK Biobank purinergic metabolomics in a within-family probands-versus-siblings design; no published SPARK dataset of this kind currently exists (see Limitations). (2) eATP-derived adenosine inhibits SAHH, driving SAH accumulation: formally documented by Naviaux 2026; a convergent SAH-elevation finding from the ASD methylation literature could not be independently verified at preprint stage and is not cited as a distinct source (see Limitations) — the mechanistic case for this link rests on Naviaux 2026 alone. (3) SAH collapse of trans-sulfuration depletes GSH biosynthetically: GSH↓ 27% in the GSH-specific subset of Chen et al. 2021 (14 studies, n ≈ 1,207; SMD = −0.89, p < 0.0001) — distinct from that meta-analysis’s full cohort (87 studies, n = 9,109), which spans all oxidative-stress markers combined, not GSH alone. (4) ROS from GSH depletion drives constitutive NLRP3 activation: directly demonstrated in ASD-derived primary fibroblasts (Vallese et al. 2024). (5) MODEL-PREDICTED / PARTIALLY SUPPORTED Microglial NLRP3-driven IL-1β produces NMDA receptor dysfunction and E/I imbalance; repetitive behavior is reversed by memantine (NMDAR antagonist) or IL-1Ra in murine models (Cell Reports 2025). NOTE: The Cell Reports 2025 study documents increased surface GluN2A (not GluN2B internalization) and NMDA hyperfunction; reversal is by memantine/IL-1Ra, not MCC950. The general mechanism (NLRP3 → IL-1β → NMDA dysfunction → behavior, pharmacologically reversible at the NMDA or IL-1R1 node) is confirmed; the specific subunit directionality and MCC950 reversal are model-predicted, not confirmed by this source. Critical gap: no study has measured all five biomarkers simultaneously in the same cohort.Unique testable prediction: Purinergic neutralization (suramin or apyrase) should produce a temporally ordered normalization cascade: SAH↓ (Days 1–7) → GSH↑ (Days 7–21) → NLRP3↓ (Days 14–30) → behavioral improvement (Weeks 4–12). This temporal ordering cannot be generated by any single-field model and specifically identifies each broken link if the sequence deviates.Conclusion: SAHH is the unmeasured enzymatic bridge between the purinergic and redox literatures in ASD. Measuring SAHH activity in ASD-derived cells with concurrent eATP profiling is the foundational experiment needed to confirm or refute the PRI cascade. We provide explicit falsification criteria for each link and a minimum viable study design (N = 80–100 observational; N = 20 mechanistic intervention).Keywords: autism spectrum disorder, purinergic signaling, Cellular Danger Response, S-adenosylhomocysteine hydrolase, SAH/SAM ratio, trans-sulfuration, glutathione, NLRP3 inflammasome, NMDA receptor, GluN2B, mechanistic hypothesis, CDR-active subtype

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