STING dampens the unfolded protein response to enable the presentation of self-antigens on MHC-I during inflammation.

Fahmy, A. M.; Ahmadi, A.; Lanoix, J.; Cannon, T.; Badr Elemeery, m. N.; Hernandez Paredes, C.; Barrette, B.; Bonneil, E.; Zhong Xu, Y.; Ibrahim, M.; Arango-Duque, G.; Audemard, E. O.; Lemieux, S.; Chevet, E.; Schurr, E.; Pierre, P.; Gruenheid, S.; Thibault, P.; McBride, H. M.; Desjardins, M.

doi:10.64898/2026.05.25.727656

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bioRxiv · 10.64898/2026.05.25.727656

STING dampens the unfolded protein response to enable the presentation of self-antigens on MHC-I during inflammation.

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Abstract

A growing body of evidence supports the contribution of the long-lasting adaptive immune system in Parkinsons disease (PD). We showed that the PD-associated protein PINK1 negatively regulates the presentation of mitochondrial antigens (MitAP) on MHC-I molecules. In vivo evidence indicated that MitAP activation in mice, in the absence of PINK1, led to cytotoxic CD8+ T cell stimulation and severe motor impairments, reversible by L-DOPA. We show here that following TLR4 activation, MitAP is engaged through a pathway involving cGAS-STING, which acts as a rheostat to dampen the unfolded protein response (UPR). Without STING, the stress response is amplified, leading to a translational attenuation that inhibits the expression of XBP1s, a transcription factor required for MitAP. STING activity also regulates the repertoire of peptides displayed at the cell surface during inflammation, highlighting a potential role in immunosurveillance. These findings establish STING and the UPR as key immune regulators targetable for therapeutic intervention during autoimmune diseases and PD.

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Fahmy, A. M., Ahmadi, A., Lanoix, J., Cannon, T., Badr Elemeery, m. N., Hernandez Paredes, C., Barrette, B., Bonneil, E., Zhong Xu, Y., Ibrahim, M., Arango-Duque, G., Audemard, E. O., Lemieux, S., Chevet, E., Schurr, E., Pierre, P., Gruenheid, S., Thibault, P., McBride, H. M., Desjardins, M.. 2026-05-28. STING dampens the unfolded protein response to enable the presentation of self-antigens on MHC-I during inflammation.. https://doi.org/10.64898/2026.05.25.727656

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