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Docosahexanoic acid signals through the Nrf2-Nqo1 pathway to maintain redox balance and promote neurite outgrowth.

ABSTRACT: Evidence suggests that n-3 polyunsaturated fatty acids may act as activators of the Nrf2 antioxidant pathway. The antioxidant response, in turn, promotes neuronal differentiation and neurite outgrowth. Nrf2 has recently been suggested to be a cell intrinsic mediator of docosohexanoic acid (DHA) signaling. In the current study, we assessed whether DHA-mediated axodendritic development was dependent on activation of the Nrf2 pathway and whether Nrf2 protected from agrochemical-induced neuritic retraction. Expression profiling of the DHA-enriched Fat-1 mouse brain relative to wild type showed a significant enrichment of genes associated with neuronal development and neuronal projection and genes associated with the Nrf2-transcriptional pathway. Moreover, we found that primary cortical neurons treated with DHA showed a dose-dependent increase in Nrf2 transcriptional activity and Nrf2-target gene expression. DHA-mediated activation of Nrf2 promoted neurite outgrowth and inhibited oxidative stress-induced neuritic retraction evoked by exposure to agrochemicals. Finally, we provide evidence that this effect is largely dependent on induction of the Nrf2-target gene NAD(P)H: (quinone acceptor) oxidoreductase 1 (NQO1), and that silencing of either Nrf2 or Nqo1 blocks the effects of DHA on the axodendritic compartment. Collectively, these data support a role for the Nrf2-NQO1 pathway in DHA-mediated axodendritic development and protection from agrochemical exposure.

SUBMITTER: Drolet J

PROVIDER: S-EPMC8101469 | biostudies-literature |

REPOSITORIES: biostudies-literature

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| S-EPMC3791369 | biostudies-literature

Soluble β-amyloid Precursor Protein Alpha binds to p75 neurotrophin receptor to promote neurite outgrowth.

Project description:BackgroundThe cleavage of β-amyloid precursor protein (APP) generates multiple proteins: Soluble β-amyloid Precursor Protein Alpha (sAPPα), sAPPβ, and amyloid β (Aβ). Previous studies have shown that sAPPα and sAPPβ possess neurotrophic properties, whereas Aβ is neurotoxic. However, the underlying mechanism of the opposing effects of APP fragments remains poorly understood. In this study, we have investigated the mechanism of sAPPα-mediated neurotrophic effects. sAPPα and sAPPβ interact with p75 neurotrophin receptor (p75(NTR)), and sAPPα promotes neurite outgrowth.Methods and findingsFirst, we investigated whether APP fragments interact with p75(NTR), because full-length APP and Aβ have been shown to interact with p75(NTR) in vitro. Both sAPPα and sAPPβ were co-immunoprecipitated with p75(NTR) and co-localized with p75(NTR) on COS-7 cells. The binding affinity of sAPPα and sAPPβ for p75(NTR) was confirmed by enzyme-linked immunosorbent assay (ELISA). Next, we investigated the effect of sAPPα on neurite outgrowth in mouse cortical neurons. Neurite outgrowth was promoted by sAPPα, but sAPPα was uneffective in a knockdown of p75(NTR).ConclusionWe conclude that p75(NTR) is the receptor for sAPPα to mediate neurotrophic effects.

| S-EPMC3864954 | biostudies-literature

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