Upregulation of Protein O-GlcNAcylation Levels Promotes Zebrafish Fin Regeneration.

As one of the most important posttranslational modifications, glycosylation participates in various cellular activities in organisms and is closely associated with many pathogeneses. It has been reported that glycosylation affects the liver, spinal cord, and heart tissue regeneration. The zebrafish fin has become a valuable model due to its high regenerative capacity. The molecular mechanism of regeneration has been a hot research topic in the field for a long time. However, studies on the influence of glycosylation during limb regeneration in zebrafish are relatively scarce. We discovered that N-acetylglucosamine (O-GlcNAc) expression, identified by WGA, was elevated during the regeneration of the injured fin in zebrafish using lectin microarray. This phenomenon is due to the upregulation of the expression of OGT enzymes and elevated O-GlcNAcylation levels. To investigate the effects on the fin regeneration when O-GlcNAcylation changes, we used OSMI-1 or alloxan unilateral microinjection to decrease O-GlcNAcylation and observed that it prevented the fin regeneration. Conversely, the O-GlcNAcylation was impressed by a unilateral microinjection of thiamet-G or glucose into the fin, leading to a stimulation of the fin regeneration. To further understand the role of O-GlcNAcylation in fin regeneration, liquid chromatography-tandem mass spectrometry technology was performed to identify O-GlcNAc-glycoproteins. The results demonstrated that the O-GlcNAc glycoproteins, such as thrombospondin 4 and heparan sulfate proteoglycans, were involved in the regulation of zebrafish fin regeneration process and were closely associated with certain biological processes, such as stem cell differentiation, extracellular matrix-receptor interaction pathway, tissue remodeling, and so on. We demonstrated that O-GlcNAc glycoproteins are crucial for zebrafish fin regeneration, during which OGT promotes the process by upregulating the O-GlcNAcylation levels in the zebrafish fin.