Environmental fluoxetine promotes skin cell proliferation and wound healing

This study investigates the effects of environmentally-relevant concentrations of fluoxetine (FLX, commercial name: Prozac) on wound healing. Pollution of water systems with pharmaceutical and care products, including antidepressants such as FLX and other selective serotonin reuptake inhibitors, is a growing environmental concern. Environmentally-relevant FLX concentrations are known to impact physiological functions and behaviour of aquatic animals, however, the effects of exposure on humans are currently unknown. Using a combination of human skin biopsies and keratinocyte cell lines, we show that exposure to environmental FLX enhances wound closure. We show dose-dependent increases in wound closure with FLX concentrations from 125 ng/l. We demonstrate that the mechanisms underlying enhanced wound closure are increased cell proliferation and serotonin signalling. Transcriptomic analysis revealed 350 differentially expressed genes after exposure. Downregulated genes were enriched in pathways related to mitochondrial function and metabolism, while upregulated genes were associated with cell proliferation and tissue morphogenesis. Kinase profiling showed altered phosphorylation of kinases related to the MAPK pathway. Consistent with this, phosphoproteomics analyses identified 235 differentially phosphorylated proteins after exposure, with enriched GO terms related to cell cycle, division, and protein biosynthesis. These findings collectively show that exposure to environmental FLX promotes wound healing through modulation of serotonin signalling, gene expression and protein phosphorylation, leading to enhanced cell proliferation. Our results open the door for further research to investigate the effects of environmental FLX on cell metabolism and proliferation, and clinical applications of FLX in the setting of wound healing. We argue that there is an urgent need to develop models that can inform on the risks, and potential benefits, of environmental pollution with selective serotonin reuptake inhibitors.