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Preprint WatchModerateJune 17th, 2026

GPCR-mediated regulation of glial TNF production

Stellwagen, D.; Abbasi, Z.; Sadighparvar, S.; Franquin, M.

Glial TNF production is bidirectionally controlled by G-protein-coupled receptor signaling, with Gs and Gq activation suppressing TNF expression and Gi activation increasing it across astrocytes and microglia.

Moderate contradiction

1 prior failure

Two documented clinical failures match this mechanism, or a single Phase 3 failure is on record.

This preprint reinforces that TNF output is highly context dependent and pathway gated rather than a single throttle that can be turned down cleanly. The indexed Claidex failure inb03-soluble-tnf-covid19-ards-futility documents INB03, a soluble TNF-directed agent, missing efficacy in COVID-19 acute respiratory distress, an acute syndrome where broad TNF neutralization did not translate into clinical benefit. The finding that distinct GPCR pathways drive glial TNF expression up or down is consistent with the difficulty of achieving a clean therapeutic effect by blocking TNF alone, and it points to cell-type and pathway-specific control as a variable that any TNF-directed program needs to account for. The preprint aligns with, rather than contradicts, the documented efficacy failure.

Abstract excerpt

Neuromodulators generally act through G-protein-coupled receptors, but their effects on glia are not well defined. Here we examine the impact of various G-protein-coupled signaling pathways on glia, using the production of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF) as a measure of activation. TNF is a major component of the innate immune response but is also an important regulator of synaptic function and can be released by both astrocytes and microglia. Using pharmacological and chemogenetic approaches, we characterized the response to activation of the Gi, Gq, and Gs signaling pathways in rat astrocyte and microglia cultures and human induced pluripotent stem cells (hiPSCs) derived astrocytes. Across all tested glia, activation of the Gs pathway results in a stark decrease in TNF expression. Similarly, activation of Gq signaling also results in a reduction in TNF mRNA levels. Conversely, Gi activation in astrocytes and microglia increases TNF levels both in vitro and in vivo. The impacts of GPCRs on TNF production were not consistent for other pro-inflammatory cytokines. Overall, this work demonstrates that G protein-mediated activation and inhibition in glia should be considered separately from the effects seen in neurons.

Matching Claidex post-mortems

1 of 1 indexed

This is an automated contradiction flag, not an editorial judgment on the preprint's quality. Flags identify where the preclinical literature and the clinical failure record diverge.