Reduced posterior-to-anterior bioelectrical coupling for dynamic tissue homeostasis in late middle-to-older organisms
June 27
In this study, we investigated age-related changes in bioelectrical coupling between key morphogenetic domains that govern posture-dependent tissue homeostasis during a mechanically demanding assay. Fourteen juvenile and fourteen late middle-to-older zebrafish maintained upright fin posture while mechanosensory input was selectively perturbed, and trans-epithelial voltage dynamics were recorded with voltage-sensitive dyes. Both age groups displayed common activation foci within the posterior morphogenetic node (PMN) and the proximal mesenchymal compartment (PrMC) throughout the assay. However, PMN-to-PrMC bioelectrical coherence was significantly weaker in the late middle-to-older group. This attenuation indicates impaired integration of peripheral mechanosensory cues required for stable tissue alignment under load. The regularity of fin-tip displacement, quantified via sample entropy, was greater in the late middle-to-older cohort, suggesting a shift from intrinsic, automatic regulation toward compensatory control. Across individuals, weaker PMN-to-PrMC coupling was associated with higher regularity of fin displacement. Notably, an additional domain—the anterior stem zone (ASZ)—was selectively recruited in late middle-to-older fish during the challenge. Together, these findings reveal an age-dependent transition from a posterior–anterior morphogenetic circuit to an ASZ-centred network for dynamic tissue homeostasis.