Differential and overlapping effects of melatonin and its metabolites on keratinocyte function: Bioinformatics and metabolic analyses

Joanna Stefan, Tae Kang Kim, Fiona Schedel, Zorica Janjetovic, David K. Crossman, Kerstin Steinbrink, Radomir M. Slominski, Jaroslaw Zmijewski, Meri K. Tulic, Russel J. Reiter, Konrad Kleszczyński, Andrzej T. Slominski

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We investigated the effects of melatonin and its selected metabolites, i.e., N1-Acetyl-N2-formyl-5-methoxykynurenamine (AFMK) and 6-hydroxymelatonin (6(OH)Mel), on cultured human epidermal keratinocytes (HEKs) to assess their homeostatic activities with potential therapeutic implications. RNAseq analysis revealed a significant number of genes with distinct and overlapping patterns, resulting in common regulation of top diseases and disorders. Gene Set Enrichment Analysis (GSEA), Reactome FIViZ, and Ingenuity Pathway Analysis (IPA) showed overrepresenta-tion of the p53-dependent G1 DNA damage response gene set, activation of p53 signaling, and NRF2-mediated antioxidative pathways. Additionally, GSEA exhibited an overrepresentation of circadian clock and antiaging signaling gene sets by melatonin derivatives and upregulation of ex-tension of telomere signaling in HEKs, which was subsequently confirmed by increased telomerase activity in keratinocytes, indicating possible antiaging properties of metabolites of melatonin. Fur-thermore, Gene Ontology (GO) showed the activation of a keratinocyte differentiation program by melatonin, and GSEA indicated antitumor and antilipidemic potential of melatonin and its metab-olites. IPA also indicated the role of Protein Kinase R (PKR) in interferon induction and antiviral response. In addition, the test compounds decreased lactate dehydrogenase A (LDHA) and lactate dehydrogenase C (LDHC) gene expression. These results were validated by qPCR and by Seahorse metabolic assay with significantly decreased glycolysis and lactate production under influence of AFMK or 6(OH)Mel in cells with a low oxygen consumption rate. In summary, melatonin and its metabolites affect keratinocytes’ functions via signaling pathways that overlap for each tested mol-ecule with some distinctions.

Original languageEnglish (US)
Article number618
Issue number4
StatePublished - Apr 2021


  • Human keratinocytes
  • Melatonin
  • Metabolites of melatonin
  • Mitochon-drial metabolism
  • RNA-sequencing

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology


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