Comparative Transcriptome Analysis Reveals Epithelial Growth Factor Receptor (EGFR) Pathway and Secreted C-Type Lectins as Essential Drivers of Leg Regeneration in Periplaneta americana.

The American cockroach (Periplaneta americana) serves as an exemplary model for regeneration research due to its exceptional regenerative capabilities, particularly in appendage regeneration. In this study, regenerated coxa tissue underwent histological analysis through H & E straining. Microscopic examination revealed the progression of regeneration. To elucidate the underlying mechanisms, a comparative transcriptomic analysis was conducted between regenerating legs and non-amputated control legs. This analysis identified 2343 differentially expressed genes (DEGs) between 0 days post-amputation (0 dpa) and 7 dpa, 2963 DEGs between 14 dpa and 0 dpa, and 3135 DEGs between 14 dpa and 7 dpa. Significantly, several DEGs are associated with growth- or regeneration-related processes, including extracellular matrix (different collagen, Pro-resilin isoforms, integrin beta (itgb) and matrix metalloproteinase (mmp)), immune-related genes (Toll-like receptor 13 (tlr13), defensin (def), drosomycin-like defensin (dld), Polyphenoloxidases2 (ppo2), cytochrome P450 (p450), peptidoglycan recognition protein (pgrp) and secreted C-type lectin (sClec)), insulin-like growth factor (IGF) and Epidermal Growth Factor Receptor (EGFR). Functional validation through RNA interference (RNAi) further suggested that EGFR and a specific C-type lectin (Regenectin) regulate leg regeneration in Periplaneta americana. These findings enhance our understanding of the molecular mechanisms governing regeneration in this species.