Zebrafish fin regeneration involves transient serotonin synthesis

Abstract

The zebrafish is a vertebrate organism capable of regenerating many of its organs. Notably, it can undergo epimorphic regeneration of its fins after amputation. This process occurs through the formation of a wound epithelium and the dedifferentiation of mesenchymal and bone‐forming cells, which form a proliferative blastema. Here, we report that the entry into the regenerative process involves the local synthesis of serotonin (5‐hydroxytryptamine, 5‐HT) in the injury‐associated tissue. One day after wounding, intracellular accumulation of serotonin was induced in the stump below the amputation plane. During blastema formation, serotonin was detected in the mesenchyme at the vicinity of the amputation plane and in the apical wound epithelium. During the advanced outgrowth phase, this monoamine was no longer present in the blastema, suggesting a temporal involvement of serotonin in the postinjury area. We show the expression of two serotonin synthesizing enzymes, tryptophan hydroxylase 1a and 1b in the blastema, suggesting the local production of this monoamine. Neither depletion of serotonin by chemical inhibition of tryptophan hydroxylase, nor ectopic administration of this monoamine affected fin regeneration, indicating it does not play a role during this process. Finally, we found that the presence of serotonin during regeneration depends on fibroblast growth factor and retinoic acid signaling. Overall, our study demonstrates that the initiation of fin regeneration is associated with a transient synthesis of serotonin in the regrowing tissue.

Distribution and Restoration of Serotonin-Immunoreactive Paraneuronal Cells During Caudal Fin Regeneration in Zebrafish

“…To test whether 5-HT is required for regeneration of HCS-cells, we applied a chemical Tph-antagonist, para-chlorophenylalanine (pcpa) (Jequier et al, 1967), which was previously validated in analytical and behavioral assays in zebrafish embryos and adults (Njagi et al, 2010; Airhart et al, 2012). Consistent with our previous study (König and Jaźwińska, 2019), we found that treatment with 5 mM pcpa, starting from 1 day before fin clipping until 3 days post-amputation, did not affect fin regeneration (Figures 15A–D). This treatment efficiently abolished 5-HT-immunoreactivity in HCS-cells, as examined on whole mount immunofluorescent stainings at 3 dpa (Figures 15A,B,E).…”

Proteomic Profiling of Stem Cell Tissues during Regeneration of Deer Antler: A Model of Mammalian Organ Regeneration

“…The Venn diagram was created in Venny (v2.1). 47 Multivariate statistical analyses, including principal component analysis (PCA) and heatmaps with hierarchical clustering analysis, were performed on significantly regulated proteins, 12 Platyhelminthes Rhabditophora whole body reparative stem cell zebrafish 15,16 Vertebrate Actinopterygii structure and organ reparative dedifferentiation and stem cell Xenopus/salamander 17,18 Vertebrate Amphibia structure and organ reparative dedifferentiation and stem cell lizard 19−22 Vertebrate Reptilia structure and tissue reparative dedifferentiation and stem cell African spiny mice 23−25 Vertebrate Mammalia tissue reparative dedifferentiation and stem cell deer 25−27 Vertebrate Mammalia structure physiological stem cell from DPP vs FP, and 153 from DPP vs MAP vs GC using R (v 3.5.2). 48 To conduct the PCA, R packages of "FactoMineR (v1.42)", 49 "factoextra (v1.0.5)", 50 "magrittr (v1.5)", 51 "ggpubr (v0.2.3)", 52 and "ggplot2 (v3.2.1)" 53 were used.…”

The Role of Tryptophan Metabolites in Neuropsychiatric Disorders

“…Then, SNA is converted to melatonin during the hydroxyindole-O-methyltransferase action. Serotonin is an essential chemical neurotransmitter, and its presence is of great importance in regulating mood, sleep, and appetite [ 34 , 35 ]. Melatonin is considered a vital neuromodulator, which has shown great potential as a strong antioxidant to regulate numerous body-related activities such as circadian rhythm and pain [ 36 , 37 , 38 , 39 ].…”