Wound‐induced cell proliferation during animal regeneration

Abstract

Many animal species are capable of replacing missing tissues that are lost upon injury or amputation through the process of regeneration. Although the extent of regeneration is variable across animals, that is, some animals can regenerate any missing cell type whereas some can only regenerate certain organs or tissues, regulated cell proliferation underlies the formation of new tissues in most systems. Notably, many species display an increase in proliferation within hours or days upon wounding. While different cell types proliferate in response to wounding in various animal taxa, comparative molecular data are beginning to point to shared wound-induced mechanisms that regulate cell division during regeneration. Here, we synthesize current insights about early molecular pathways of regeneration from diverse model and emerging systems by considering these species in their evolutionary contexts. Despite the great diversity of mechanisms underlying injury-induced cell proliferation across animals, and sometimes even in the same species, similar pathways for proliferation have been implicated in distantly related species (e.g., small diffusible molecules, signaling from apoptotic cells, growth factor signaling, mTOR and Hippo signaling, and Wnt and Bmp pathways). Studies that explicitly interrogate molecular and cellular regenerative mechanisms in understudied animal phyla will reveal the extent to which early pathways in the process of regeneration are conserved or independently evolved. This article is categorized under: Comparative Development and Evolution > Body Plan Evolution Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration Comparative Development and Evolution > Model Systems.

BMP signaling is required for amphioxus tail regeneration

“…Novel findings of this study are that bmp2/4 is immediately induced by wounding and that BMP signaling is required for wound healing after amputation. In contrast, in epimorphic regeneration of other species, the roles of BMP signaling are mainly related to cell proliferation (Ricci and Srivastava, 2018;Wagner et al, 2017). It is noticeable that in European amphioxus, msx (a target gene of BMP signaling) is expressed in the mesenchyme of the blastema (Somorjai et al, 2012a), combining the expression patterns of BMP signaling genes during tail regeneration of B. japonicum shown by us ( Fig.…”

Un trio de mécanismes au cœur de l’initiation de la régénération chez les animaux

“…Cette perméabilisation est gouvernée par l'action antagoniste de protéines de la famille Bcl2, pro-apoptotiques (Bax, Bak, Bid, de régénération. Nous ne détaillerons ici que quelques-unes de ces molécules (pour une liste détaillée de ces molécules et des voies de signalisation qui leur sont associées, voir [11,22]). Une étude pionnière, portant sur la régénération de la tête chez l'hydre, a montré que les cellules apoptotiques émettaient des protéines Wnt3 4 , et que celles-ci étaient nécessaires à la prolifération cellulaire et à une régénération correcte [15].…”

“…La méthode TUNEL est décrite dans le texte principal, et « immunomarquage » indique l'utilisation d'anticorps marquant les cellules en apoptose, en particulier celle d'anticorps dirigés contre la forme clivée active des capsases effectrices. L'ensemble des informations de cette figure a été synthétisé à partir de[11,22].…”

And Then There Were Three…: Extreme Regeneration Ability of the Solitary Chordate Polycarpa mytiligera

“…The phylogenetic distribution of regeneration across the metazoans raises the possibility of this ability being an ancestral feature, and emphasizes the importance of comparative studies employing new model systems in order to gain insight into the evolution of regeneration and the mechanisms that determine its variation across species (Bely and Nyberg, 2010;Giangrande and Licciano, 2014;Grillo et al, 2016;Slack, 2017;Ricci and Srivastava, 2018;Mehta and Singh, 2019).…”