Comparative proteomics analysis of growth-primed adult dorsal root ganglia reveals key molecular mediators for peripheral nerve regeneration

Injuries to peripheral nerves are frequent, yet no drug therapies are available for effective nerve repair. The slow growth rate of axons and inadequate access to growth factors challenge natural repair of nerves. A better understanding of the molecules that can promote the rate of axon growth may reveal therapeutic opportunities. Molecular profiling of injured neurons at early intervals of injury, when regeneration is at the maximum, has been the gold standard for exploring growth promoters. A complementaryin vitroregenerative priming model was recently shown to induce enhanced outgrowth in adult sensory neurons. In this work, we exploited thein vitropriming model to reveal novel candidates for adult nerve regeneration. We performed a whole tissue proteomics analysis of thein vitroprimed DRGs from adult SD rats and compared their molecular profile with that of thein vivoprimed, and control DRGs. The proteomics data generated are available via ProteomeXchange with identifier PXD031927. From the follow-up analysis, Bioinformatics interventions, and literature curation, we identified several molecules that were differentially expressed in the primed DRGs with a potential to modulate adult nerve regrowth. We then validated the growth promoting roles of mesencephalic astrocyte-derived neurotrophic factor (MANF), one of the hits we identified, in adult rat sensory neurons. Overall, in this study, we explored two growth priming paradigm and shortlisted several candidates, and validated MANF, as potential targets for adult nerve regeneration. We also demonstrate that thein vitropriming model is a valid tool for adult nerve regeneration studies.Significance statementSevere damages to peripheral nerves often lead to permanent functional disability. However, no pharmacological therapies are currently available for effective nerve repair due to the lack of knowledge of potent molecular targets. In this work, we performed whole tissue proteomics studies using two growth priming models and revealed novel molecular candidates, including mesencephalic astrocyte-derived neurotrophic factor (MANF), for peripheral nerve regeneration. This work not only generated a large list of potential molecular candidates for future research but also characterized a novelin vitromodel at the molecular level for nerve regeneration studies.