Fight disease by making this change to your nighttime routine

Circadian rhythm – the body’s “clock” – governs our sleep-wake cycle. Whether you are a “morning” or a “night owl” is a behavioral consequence of how your genes affect your “body clock”. When that clock is out of time, so to speak, the effects are obvious: jet lag is the manifestation of a disturbed circadian rhythm, for example.

But circadian rhythm, a 24-hour biological process that aligns our bodies with the Earth’s rotation, also controls metabolism, body temperature, hormones, and the immune system. Various health conditions and diseases, in turn, exhibit a “circadian component” and, in some cases, can be a direct result of faulty circadian clocks.

In a study published Tuesday in the journal Genomic research, scientists report the circadian rhythm influences our ability to fight disease to a higher degree than previously achieved. The research represents a new understanding of an ancient process – and offers an important reminder that good “sleep hygiene” is essential for health far beyond feeling well rested.

Why is this important – Ultimately, research suggests that accurate tracking of circadian rhythms is essential for understanding how the body protects against disease. By changing your approach to sleep, you may be able to dramatically change the course of your health.

Principal author Jennifer Hurley is an Assistant Professor at Rensselaer Polytechnic Institute. His research focuses on the fundamental mechanisms underlying circadian rhythms and how they affect human health. She says Reverse that scientists already knew that chronic disruptions to the circadian clock over the course of a lifetime can lead to an increased risk of certain diseases, ranging from cancer to heart disease. What was not known, however, is How? ‘Or’ What this disruption leads to increased risk.

“We had observed that all diseases associated with chronic circadian disruption were also linked to inflammation, which is a product of the immune system,” says Hurley.

“However, a deep understanding of how the clock controls the immune system, in cells or in organisms, did not exist. This study aimed to help fill this knowledge gap. “

What is the circadian rhythm?

Each cell in the body has its own biological clock. These tiny timers are coordinated by a central clock in the brain called the suprachiasmatic nucleus, or SCN. It controls and synchronizes the circadian rhythm while keeping everything in time with the rotation of the Earth. Circadian rhythms are found in almost all terrestrial organisms – even plants are prompted by a circadian rhythm to open their leaves during the day and close them at night.

Circadian rhythms play a role in many processes underlying immunity, and chronic circadian disturbances are linked to an increased risk of metabolic, cardiovascular and neurodegenerative diseases. These health issues all share underlying inflammatory components – which is why there is a hypothesis that deregulation of immunity, which can manifest as chronic inflammation, for example, may be the link between the disease and the circadian rhythm.

The so-called “cogs” of biological clocks are genes and proteins, while macrophages – white blood cells in the immune system that detect and destroy harmful and invasive organisms like bacteria – play a vital role in “intuition. , maintenance and resolution of both acute and chronic inflammation, ”according to the study. The authors explain that macrophages can exert a disproportionate influence on the functioning of circadian clocks because they live for months at a time in the bloodstream.

Macrophages, Hurley and his team discovered weather changes in their responses to pathogens and stress via circadian control of metabolism. But the precise nature of their timing was totally unexpected, Hurley said.

“We have learned that the circadian control mechanisms in the cell are more complex than we previously thought, which means that there is probably more control over circadian rhythms than we thought,” says Hurley.

“Our study has a lot of potential to advance science.”

Dig into the details – To understand the study, explains Hurley, it is necessary to know that the “central dogma of biology” is that DNA (our genes), makes RNA (transcripts of genes) and proteins (the “actors” of the cell).

“As a field, we were making inferences about what the circadian clock was doing in the body by looking at the transcripts as a proxy for proteins with a circadian rhythm,” Hurley says.

“However, as a protein biochemist, I know that a lot happens when the transcripts are turned into proteins and by looking only at the transcripts we would miss a lot of what was going on in the cell.

Specifically, the study team looked at how RNA and protein levels in macrophages changed in two days – finding 80 percent of circadian protein. does not have have a transcript that also had a circadian rhythm. Subsequent analysis also revealed the interaction of circadian rhythm and metabolism multiplied by essentially the immune functions of macrophages – a process that results from the division and fusion of mitochondria.

The team also found the proteins involved in Covid-19 infection have a circadian rhythm, “which could play an important role in the immune response to this viral infection,” says Hurley.

Can you help your circadian rhythm fight disease?

According to Hurley: “Absolutely!”

The first thing people can do, she explains, is train good sleep hygiene. This can be divided into three elements:

1. Sleep eight hours a night
2. Do not expose yourself to bright lights at night
3. Maintain a regular daily schedule to wake you up naturally, without waking up

“The key to all of this is to avoid exposure to bright light at night, which can really disrupt your circadian rhythm,” says Hurley. In other words: put down your smartphone or tablet before going to bed at night.

Understanding how the immune system responds to disease is key to finding ways to combat these challenges. Here, the study team discovered a little-known way the body works to protect itself against disease – and how certain habits and actions we take can cause these defense mechanisms to malfunction or become stronger.

In the future, Hurley hopes the study “can help others discover what these new mechanisms are and how they work.”

Abstract: Our central timing mechanism, the circadian clock, plays an essential role in immunity. Although the mechanics of circadian control of the immune response is generally explained by transcriptional activation or repression derived from the negative transcription-translational feedback loop of this clock, research suggests that some regulation occurs beyond of transcriptional activity. We exhaustively profiled the transcriptome and proteome of macrophages derived from murine bone marrow and found that only 15% of the circadian proteome had the corresponding oscillating mRNA, suggesting that post-transcriptional regulation influences the output of regulation. of the macrophage clock to a greater extent than any other previously profiled tissue. This regulation can be explained by the robust temporal enrichment that we have identified for the proteins involved in degradation and translation. Extended post-transcriptional temporal onset of metabolic pathways was also observed and further corresponded to daily variations in ATP production, mitochondrial morphology, and phagocytosis. Disruption of this circadian post-transcriptional metabolic regulation altered immune functionality. Our results demonstrate that post-transcriptional regulation intrinsic to cells is a major driver of circadian production in macrophages and that this regulation, in particular of metabolic pathways, plays an important role in determining their response to immune stimuli.