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ZFIN ID: ZDB-PUB-150313-2
Melatonin regulates the rhythmic migration of neutrophils in live zebrafish
Ren, D.L., Li, Y.J., Hu, B.B., Wang, H., Hu, B.
Date: 2015
Source: Journal of pineal research   58(4): 452-60 (Journal)
Registered Authors: Wang, Han
Keywords: circadian rhythms, cytokines, melatonin, migration, neutrophil, zebrafish
MeSH Terms:
  • Animals
  • Circadian Rhythm/drug effects
  • Melatonin/pharmacology*
  • Neutrophils/cytology*
  • Neutrophils/drug effects*
  • Zebrafish
PubMed: 25763660 Full text @ J. Pineal Res.
The circadian clock plays a vital role in physiology and behavior such as the sleep-wake cycle and blood pressure and hormone levels. Immune responses also display circadian rhythmicity and particularly pineal melatonin contributes to immunological┬áprocesses. Little attention, however, is given to mechanisms underlying rhythmic neutrophil responses to the injury. Here we used a transgenic Tg(lyz:EGFP) zebrafish tail-fin transection model to investigate whether the recruitment of neutrophils towards the injured site is regulated by the circadian clock. We found that migrating neutrophils display robust rhythmicity, peaking at darkness. Melatonin positively regulates rhythmic neutrophil migration, as evidenced that treatment with melatonin at low dosage can significantly enhance neutrophil recruitment towards the injured site, which is attenuated by luzindole treatment and in pinealectomized fish. Furthermore, using a transgenic zebrafish eyeball model, we observed that melatonin enhances secretion of two cytokines, TNF-α and IL-8, both of which markedly enhance neutrophil migration. Taken together, these results highlight a positive role of melatonin in rhythmic neutrophil migration and help obtain a better understanding of circadian regulation in immunology. This article is protected by copyright. All rights reserved.