Circadian rhythms are the body’s intrinsic 24-hour cycles, governing sleep, metabolism, immunity, and hormone secretion. But the machinery that keeps these cycles ticking is far more complex than the handful of clock genes taught in textbooks, and a new review in Cancer Cell International maps a layer of regulation that has only come into focus in recent years: non-coding RNAs.
The review, by an international team led by Cairo University researchers, synthesizes the emerging evidence that microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) are not passive bystanders but active regulators of the circadian clockwork. And when circadian misalignment disrupts their expression, the consequences ripple across nearly every disease category.
Key points
The core molecular clock operates through transcriptional-translational feedback loops involving genes like CLOCK, BMAL1, PER, and CRY. Non-coding RNAs fine-tune this system at multiple levels:
- miRNAs modulate clock gene expression post-transcriptionally, acting as rheostats that adjust the amplitude and timing of circadian oscillations.
- lncRNAs function as scaffolds, transcriptional regulators, or competing endogenous RNAs (sponges) that sequester miRNAs and alter their availability.
- circRNAs form stable loops that can also act as miRNA sponges, adding another layer of regulatory complexity.
Circadian disruption, from shift work, jet lag, genetic variants, or poor sleep, alters ncRNA expression patterns. This dysregulation has been linked to:
- Cancer
- Cardiovascular disorders
- Autoimmune conditions
- Gastrointestinal dysfunction
- Neurological and psychiatric diseases
- Respiratory illnesses
Why it matters
The clinical promise lies in two directions. First, circulating miRNAs in blood or saliva could serve as biomarkers for circadian disruption, enabling clinicians to measure a patient’s circadian health objectively rather than relying on questionnaires. Second, ncRNAs themselves may become therapeutic targets: restoring their expression or blocking their dysregulation could re-stabilize circadian function in patients whose clocks have gone awry.
The authors frame this as a foundation for personalized chronotherapy, tailoring the timing and type of treatment to an individual’s circadian profile and ncRNA signature.
Limits
The ncRNA-circadian field is young. Most evidence comes from cell lines or animal models, and the clinical translation, validated biomarkers, druggable targets, remains aspirational. The field must also contend with the sheer complexity: a single lncRNA can regulate dozens of targets, making specificity a challenge.
Bottom line
Non-coding RNAs are emerging as key regulators of the circadian clock, and their disruption helps explain how circadian misalignment drives disease. Circulating ncRNAs may soon join actigraphy and melatonin profiling as tools for assessing circadian health.
Source
Abdelmawla MA, et al. Circadian rhythms and non-coding RNAs: mechanistic insights, clinical impact, and future opportunities for personalized medicine. Cancer Cell Int. 2026 Jun 17;26(1):233. DOI: 10.1186/s12935-026-04369-1. PMID: 42310674.