Local Synthesis of Reticulon-1C Lessens the Outgrowth of Injured Axons by Controlling Spastin Activity

Luarte, A.; Gallardo, J.; Corvalan, D.; Chakraborty, A.; Gouveia-Roque, C.; Bertin, F.; Contreras, C.; Ramirez, J. P.; Weber, A.; Acevedo, W.; Zuschratter, W.; Herrera, R.; Wyneken, U.; Paula Lima, A.; Adasme, T.; Figueroa, A.; Gonzalez, C.; Gonzalez-Billault, C.; Hengst, U.; Couve, A.

doi:10.1101/2024.08.11.607514

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bioRxiv · 10.1101/2024.08.11.607514

Local Synthesis of Reticulon-1C Lessens the Outgrowth of Injured Axons by Controlling Spastin Activity

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Abstract

The regenerative potential of developing cortical axons depends on intrinsic mechanisms, such as axon-autonomous protein synthesis, that are still not fully understood. An emerging factor in this regenerative response is the bi-directional interplay between microtubule dynamics and the axonal endoplasmic reticulum (ER). We hypothesize that locally synthesized ER proteins regulate microtubule dynamics and the regeneration of cortical axons. RNA data-mining identified the ER-shaping protein Reticulon-1 as a relevant candidate across eight axonal transcriptomes. Using microfluidic chambers, we demonstrate that local knockdown of Reticulon-1 synthesis increases the outgrowth of injured cortical axons while reducing their distal tubulin levels. Furthermore, we show by live-cell imaging that axonal Reticulon-1 knockdown restores the microtubule growth rate and track length modified by injury. Interestingly, local inhibition of the microtubule- severing protein Spastin prevents the axonal knockdown-mediated effects over outgrowth and tubulin levels. We demonstrate that the Reticulon-1C isoform is locally synthesized within axons and support its isoform-specific role in attenuating Spastin-mediated microtubule severing. These findings uncover a mechanism by which axonal protein synthesis finely controls microtubule dynamics and outgrowth upon injury.

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Luarte, A., Gallardo, J., Corvalan, D., Chakraborty, A., Gouveia-Roque, C., Bertin, F., Contreras, C., Ramirez, J. P., Weber, A., Acevedo, W., Zuschratter, W., Herrera, R., Wyneken, U., Paula Lima, A., Adasme, T., Figueroa, A., Gonzalez, C., Gonzalez-Billault, C., Hengst, U., Couve, A.. 2024-08-12. Local Synthesis of Reticulon-1C Lessens the Outgrowth of Injured Axons by Controlling Spastin Activity. https://doi.org/10.1101/2024.08.11.607514

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