Nfe2l3 promotes neuroprotection and long-distance axon regeneration after injury in vivo [bulkRNA-seq]

Nuclear factor erythroid 2 like (Nfe2l) gene family members 1-3 mediate cellular response to oxidative stress, including in the central nervous system (CNS). However, neuronal functions of Nfe2l3 are unknown. Here, we comparatively evaluated expression of Nfe2l1, Nfe2l2, and Nfe2l3 in singe cell RNA-seq (scRNA-seq)-profiled cortical and retinal ganglion cell (RGC) CNS projection neurons, investigated whether Nfe2l3 regulates neuroprotection and axon regeneration after CNS injury in vivo, and characterized a gene network associated with Nfe2l3 in neurons. We showed that, Nfe2l3 expression transiently peaks in developing immature cortical and RGC projection neurons, but is nearly abolished in adult neurons and is not upregulated after injury. Furthermore, within the retina, Nfe2l3 is enriched in RGCs, whereas Nfe2l1 and Nfe2l2 are expressed robustly in other retinal cell types as well, and are also upregulated after injury. We also found that, expressing Nfe2l3 in injured RGCs through localized intralocular viral vector delivery promotes neuroprotection and long-distance axon regeneration after optic nerve injury in vivo. Moreover, Nfe2l3 treatment provided a similar extent of neuroprotection and axon regeneration as viral vector-targeting of Pten and Klf9, which are prominent regulators of neuroprotection and long-distance axon regeneration. Finally, we bioinformatically characterized a gene network associated with Nfe2l3 in neurons, which revealed the association of Nfe2l3 with established mechanisms of neuroprotection and axon regeneration. Thus, Nfe2l3 is a novel neuroprotection and axon regeneration-promoting factor with a therapeutic potential for treating CNS injury and disease. Bulk-RNA-seq samples from postnatal day 5 RGCs were purified by immunopanning for Thy1 (after immunopanning depletion of macrophages). RNA with RNA Integrity Number (RIN) ≥ 9 (by Bioanalyzer 2100 using the Nano 6000 kit, Agilent) was extracted using Direct-zol RNA MiniPrep kit (R2050, Zymo Research). The RNA was processed and cDNA libraries were prepared using RiboZero and ScriptSeq v2 kit (Epicentre) which depletes rRNAs. Paired reads were sequenced in a DNA-strand-specific manner, 100 bp from each end, on HiSeq 2000 Sequencer (Illumina), passed QC filters, mapped to the mm10 genome and transcriptome by Hisat2, and analyzed by Cufflinks/CuffDiff. Transcript isoforms expressed > 0.1 FPKM were retained and visualized using IGV browser.