Annals of the New York Academy of SciencesOct 26, 2026

Two-Way Relationship Between Body Clock Genes and Reactive Oxygen Production in Carp and Zebrafish Immune Cells

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Oct 27, 2026

Abstract

Carp and zebrafish monocytes/macrophages exhibit a functional circadian system that influences reactive oxygen species (ROS) production.

Core clock genes in carp monocytes/macrophages are expressed rhythmically under both light:dark and constant dark conditions.
Reactive oxygen species production varies throughout the day, suggesting a link between circadian rhythms and immune function.
Ex vivo stimulation with immune signals and cortisol alters the expression of clock genes in monocytes/macrophages.
Direct addition of ROS donors increases the expression of multiple clock genes, indicating a reciprocal relationship.
Inhibition of NADPH oxidase reduces ROS production and alters clock gene expression, highlighting the interaction between these pathways.
Zebrafish mutants lacking the cry1 gene show changes in ROS production, further supporting the influence of the circadian clock on redox activity.

Simplified

Our study investigated the bidirectional interaction between circadian clock genes and reactive oxygen species (ROS) production in fish monocytes/macrophages (Mo/Mf). Macrophages are key leukocytes whose antimicrobial activity relies on ROS generation. As ROS levels fluctuate across the day and clock genes regulate numerous cellular processes, we examined whether macrophage clock gene activity and ROS production are functionally interconnected. We found that carp Mo/Mf displayed constitutive expression of core clock genes and genes involved in melatonin synthesis and redox balance: Clock genes (per2, clock, cry2, and bmal2) showed rhythmic expression under both light:dark and constant dark conditions and ROS production varied across the day. Ex vivo cell stimulation revealed that immune signals, cortisol, and ROS‑modulating agents altered clock gene expression. Direct ROS donors upregulated multiple clock genes, while inhibition of NADPH oxidase reduced ROS production and changed expression of clock genes. Finally, zebrafish mutants lacking cry1 exhibited changes in ROS production, demonstrating that disruption of the circadian clock affects redox activity. Together, these findings show that carp and zebrafish Mo/Mf possess a functional circadian system and that the ROS and clock pathways influence each other. This interplay may shape daily patterns of immune responsiveness and contribute to time‑dependent variation in host defense.

Full Text

Full text is available at the source.

View Full Text ↗

Two-Way Relationship Between Body Clock Genes and Reactive Oxygen Production in Carp and Zebrafish Immune Cells

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

What Lands in Your Inbox Each Week:

Recent issues from the circadian biology brief