Exposure to daylight stimulates the immune system, the study suggests: Scienceatt

Have you already discovered yourself synchronization with normal sleep habits after the end of the nights or to work a quarter night? It might be that you are experiencing what scientists call Social time difference.

The term describes the disalember between our internal body clock (circadian rhythm) and our social schedule.

The social jet lag associated with irregular sleep habits and an incoherent exposure to daylight is increasingly common and has been linked to a weakened immune system.

The disruption of our circadian rhythms through the work of a quarter work, for example, was It is shown that it has a negative impact On our ability to fight infections.

These observations reinforce the idea that maintaining a robust circadian pace by regular exposure to daylight supports a healthy immune system.

But how does the immune system know when it’s the day? This is precisely what our research, Published today in scientific immunologydiscovered. Our results could possibly provide advantages for the treatment of inflammatory conditions.

First stakeholders in infection

Circadian rhythms are a fundamental characteristic of all life on earth. According to organizations, they evolved around 2.5 billion years ago, they allow organizations to adapt to the challenges associated with solar day 24 hours a day.

At the molecular level, these circadian rhythms are orchestrated through a multi-component goalkeeper genetically called a circadian clock. Almost all cells are known to have the components of a circadian clock. But the way they operate in different types of cells to regulate their behavior is very poorly understood.

In the laboratory, we use zebra fish – small freshwater fish commonly sold in pet stores – as a model organism to understand our immune response to bacterial infection.

We use larval zebra fish because their genetic makeup and their immune system are similar to ours. In addition, they have transparent bodies, which facilitates observation of biological processes under the microscope.

We focus on an immune cell called “neutrophilic“, a type of white blood cells. We are interested in these cells because they specialize in the death of bacteria, are the first stakeholders in infection and are the most abundant immune cell in our body.

Because they are very short duration cells, neutrophils isolated from human blood are notoriously difficult to work with experimentally. However, with transparent larval zebra fish, we can film them to directly observe the functioning of these cells, in a completely intact animal.

Cells can say if it’s the day

Our initial studies have shown that the force of the immune response to bacterial infection culminated during the day, when animals are active.

We believe that this represents an evolutionary response which provides both man and zebra fish an advantage of survival. Because daytime animals such as humans and zebra fish are the most active during hours of clarity, they are more likely to meet bacterial infections.

This work made us curious about how this improved immune response was synchronized in daylight. By making neutrophilic films killing bacteria at different times of the day, we discovered that they had killed bacteria more effectively during the day than at night.

We then genetically published neutrophils to turn off their circadian clocks by carefully eliminating specific clock components. This is an approach similar to the removal of the important cogs of an analog clock so that it no longer checks.

This has led to the discovery that these important immune cells have a circadian clock regulated by internal light which alerts the cells of the day (similar to an alarm clock). This strengthens their ability to kill bacteria.

Our next challenge is to understand exactly how light is detected by neutrophils and if human neutrophils are also based on this internal synchronization mechanism to regulate their antibacterial activity.

We are also curious to see if this killing mechanism is limited to certain types of bacteria, such as those that we are more likely to meet during the day. Or is it a more general response to all infectious threats (including viral infections)?

This research unlocks the development potential of drugs that target the circadian clock of neutrophils to regulate cell activity. Since neutrophils are the first and most abundant immune cells to be recruited from inflammation sites, discovery has very large implications for many inflammatory conditions.

The research described here was led by the candidates for the Lucia du and Pramuk Keerthizinghe doctorate candidates, and was a collaboration between the Hall laboratory and the Chronobiology Research Group, led by Guy Warman and James Cheeseman, at the Faculty of Medical Sciences and Health of the University of Auckland.

Chris HallAssociate Professor of Immunology, University of Auckland, Waipapa Taumata Rau

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