Sexual dimorphism is a powerful yet understudied factor that influences the timing and efficiency of gene regulation in axonal injury and repair processes in the peripheral nervous system. Here, we identified common and distinct biological processes in female and male degenerating (distal) nerve stumps based on a snapshot of transcriptional reprogramming 24 h after
axotomy reflecting the onset of early phase
Wallerian degeneration (WD). Females exhibited transcriptional downregulation of a larger number of genes than males.
RhoGDI, ERBB, and ERK5 signaling pathways increased activity in both sexes. Males upregulated genes and canonical pathways that exhibited robust baseline expression in females in both axotomized and
sham nerves, including signaling pathways controlled by
neuregulin and
nerve growth factors.
Cholesterol biosynthesis, reelin signaling, and synaptogenesis signaling pathways were downregulated in females. Signaling by Rho Family
GTPases, cAMP-mediated signaling, and
sulfated glycosaminoglycan biosynthesis were downregulated in both sexes.
Estrogens potentially influenced sex-dependent injury response due to distinct regulation of
estrogen receptor expression. A crosstalk of
cytokines and growth
hormones could promote sexually dimorphic transcriptional responses. We highlighted prospective regulatory activities due to
protein phosphorylation, extracellular proteolysis, sex chromosome-specific expression,
major urinary proteins (MUPs), and genes involved in
thyroid hormone metabolism. Combined with our earlier findings in the corresponding dorsal root ganglia (DRG) and regenerating (proximal) nerve stumps, sex-specific and universal early phase molecular triggers of WD enrich our knowledge of transcriptional regulation in
peripheral nerve injury and repair.