Comparative multi-omic analysis reveals conserved and derived mechanisms of fin and limb regeneration [spatial transcriptomics II]

Comparative studies of vertebrate appendages offer a powerful framework for uncovering shared components of an ancestral regeneration toolkit. Here, we employed a multi-omics comparative approach leveraging the regenerative capacity of the axolotl, zebrafish, and Polypterus senegalus, a fish capable of full fin regeneration. We identified conserved markers of proximal and distal blastema territories, shared activation of DNA damage repair, hif1a-mediated hypoxia response, and sequential activation of pro- and anti-inflammatory program. Apical epithelial ridge markers were expressed in both the wound epidermis and distal mesenchyme during limb and fin regeneration. Notably, hif4a-expressing erythrocytes were uniquely associated with proximal limb and fin amputations but not fin rays, while epidermal myoglobin expression was upregulated only in Polypterus and zebrafish fins. Genome-wide chromatin profiling identified candidate regeneration-responsive elements and a conserved enrichment for AP-1 transcription factor binding. Together, these finding identify shared and derived mechanisms of limb and fin regeneration. Overall design: Cryosections of axolotl limbs at homeostasis (intact) and at different time points of regeneration (3, 7 and 14 dpa) were used for spatial transcriptomics analysis.