Nuclear S-nitrosylation impacts tissue regeneration in zebrafish

Area of Science:

• Molecular Biology
• Regenerative Medicine
• Biochemistry

Background:

• Nitric oxide (NO) signaling is vital in numerous biological processes.
• The specific function of NO in tissue regeneration is not well understood.
• Inducible nitric oxide synthase (iNos) is an enzyme involved in NO production.

Purpose of the Study:

• To investigate the role of nitric oxide signaling in zebrafish tailfin regeneration.
• To identify the molecular mechanisms by which NO influences tissue repair.
• To determine if S-nitrosylation is a critical post-translational modification in regeneration.

Main Methods:

• Tracking of inducible nitric oxide synthase (iNos) localization during regeneration.
• Assessment of nuclear S-nitrosylated proteome changes using mass spectrometry.
• Inhibition of iNos and nitric oxide scavenging to evaluate effects on regeneration.
• Analysis of Kdm1a S-nitrosylation and its impact on epigenetic activity.
• Rescue experiments to confirm the necessity of S-nitrosylation.

Main Results:

• iNos translocates to the nucleus during zebrafish tailfin regeneration.
• Inhibition of iNos or nitric oxide scavenging impairs tailfin regeneration and reduces protein S-nitrosylation.
• A significant increase in S-nitrosylated proteins, including the epigenetic modifier Kdm1a, was observed during regeneration.
• S-nitrosylation of Kdm1a on Cys334 affects its interaction with the CoRest complex and H3K4 demethylase activity in endothelial cells.
• S-nitrosylation was confirmed as essential for tailfin regeneration, with identified downstream endothelial targets.

Conclusions:

• S-nitrosylation is an essential post-translational modification that plays a critical role in tissue regeneration.
• Nitric oxide signaling, through S-nitrosylation, regulates epigenetic modifications in endothelial cells, thereby promoting tailfin regrowth.
• This study elucidates a novel mechanism linking NO signaling to epigenetic regulation in the context of tissue repair.