This research, published in the science of immunology, reveals that neutrophils, the most common white blood cell, possess internal clocks that respond to daylight, boosting immune strength during daytime hours.
What, how, and why?
Scientists observed immune cells in real time using transparent Zebrafish, which share significant genetic similarities with humans. What they discovered was astonishing: These cells are more active and effective during daylight, suggesting that our immune system is optimized to combat pathogens when it comes into direct contact with daylight. The zebrafish model enabled the researchers to manipulate light cycles and visually monitor the impact of circadian interference on immunity.
What is a zebrafish?
Zebrafish, scientifically known as Danio rerio, are small tropical freshwater fish that are widely used in studies, especially in the fields of genetics, biology, and immunology.
A unique fact about this organism is its genetic similarity to humans. About 70% of human genes have a counterpart in zebrafish, making them valuable for studying human diseases.The findings have profound implications. People whose circadian rhythms(which refers to a natural process that regulates the sleep-wake cycle and other biological functions) have been disrupted, like night-shift workers, international travellers who have crossed multiple time zones, or those with limited access to natural daylight, can experience impaired immune function. It also provides a new level of insight into controlling chronic inflammatory disorders, which tend to be worsened by circadian desynchronization.
Experts propose that routine exposure to natural light, particularly in the morning (early morning before 10 am), may be a straightforward, non-drug approach to maintaining immune function. This is consistent with current guidance regarding the value of light for regulating sleep, mental health, and, it now appears, resistance to infection.The research team thinks this finding may lead to new avenues in creating light-based treatments or therapies that coordinate drug delivery with the body’s own immune peaks, ultimately making drugs work better.Since the world is still struggling with infectious diseases, this research highlights a basic but usually ignored instrument in public health: sunlight. While too much UV exposure has its own dangers, a moderate daily dose of daylight could be a good friend to supporting immunity.
What are the relevant findings of this research?
The study further identifies the gene Per2, a crucial neurohormone that produces reactive oxygen species molecules that kill bacteria and expresses hmgb1a, which is a known protein that supports immune response. In addition, the scientists found a conserved cis-regulatory element, a genetic “switch” that is responsible for regulating the timing of hmgb1a expression. This element contains sites for binding both BMAL1, a core clock protein, and NF-κB, a protein complex that is key to immune response regulation.
These elements, combined, make certain that neutrophils are prepared to combat infection during the organism’s active, daylight phase. When the neutrophil BMAL1-binding motif was mutated, the light-priming effect was attenuated, resulting in a considerable decline in the bactericidal capacity of the cells and hmgb1a expression. This highlights the pivotal role of this light-sensitive molecular timer in immune function. These results have important implications for those with perturbed circadian rhythms, including shift workers and patients with chronic inflammatory disorders. Daily exposure to natural sunlight might enhance a more robust immune response and guide novel therapeutic approaches. The question stands: Will you ‘sunbathe’ to improve your immune system?
