Phenotypic Screening Following Transcriptomic Deconvolution to Identify Transcription Factors Mediating Axon Growth...

Area of Science:

• Neuroscience
• Molecular Biology
• Regenerative Medicine

Background:

• Central nervous system (CNS) injuries severely limit axon regeneration due to intrinsic neuronal factors and environmental inhibitors.
• Identifying molecular mechanisms that promote axon regrowth is critical for developing effective CNS repair strategies.

Purpose of the Study:

• To identify transcriptional regulators involved in promoting axon growth following CNS injury.
• To understand the molecular pathways activated by the kinase inhibitor RO48 that enhance neurite outgrowth.

Main Methods:

• RNA sequencing (RNA-seq) was used to analyze gene expression changes in rat hippocampal neurons treated with RO48.
• Transcription factor binding site enrichment analysis identified potential transcription factors regulating differential gene expression.
• A phenotypic loss-of-function screen and subsequent validation were performed to assess the role of identified transcription factors in neurite outgrowth.

Main Results:

• Transcriptomic analysis identified 82 transcription factor motifs associated with RO48-induced neurite outgrowth.
• Several known regulators of axon growth (e.g., Jun, Klf4, Myc) were identified, alongside novel candidates.
• The Forkhead box (Fox) family transcription factor Foxp2 was found to restrict neurite outgrowth, while Foxo1 and Foxo3a promote it.

Conclusions:

• A combined transcriptomic and phenotypic screening approach successfully identified novel transcriptional regulators of CNS axon growth.
• Specific Fox family members (Foxp2, Foxo1, Foxo3a) play opposing roles in regulating neurite outgrowth.
• These findings provide new molecular targets for promoting CNS regeneration after injury.