New Link Between a Disrupted Body Clock and Inflammatory Diseases

Summary: Study identifies a significant way in which a disrupted circadian clock drives inflammation in the body’s immune cells.

Source: RCSI

New research from RCSI has demonstrated the significant role that an irregular body clock plays in driving inflammation in the body’s immune cells, with implications for the most serious and prevalent diseases in humans. 

Published in Frontiers in Immunology, the research was led by the School of Pharmacy and Biomolecular Sciences at RCSI University of Medicine and Health Sciences.

The circadian body clock generates 24-hour rhythms that keep humans healthy and in time with the day/night cycle. This includes regulating the rhythm of the body’s own (innate) immune cells called macrophages.

When these cell rhythms are disrupted (due to things like erratic eating/sleeping patterns or shift work), the cells produce molecules which drive inflammation. This can lead to chronic inflammatory diseases such as heart disease, obesity, arthritis, diabetes and cancer, and also impact our ability to fight infection.

In this study, the researchers looked at these key immune cells called macrophages with and without a body clock under laboratory conditions. They were interested to understand if macrophages without a body clock might use or ‘metabolise’ fuel differently, and if that might be the reason these cells produce more inflammatory products.  

This shows the outline of two heads covered in tree branches
The researchers found that macrophages without a body clock took up far more glucose and broke it down more quickly than normal cells. Image is in the public domain

The researchers found that macrophages without a body clock took up far more glucose and broke it down more quickly than normal cells. They also found that, in the mitochondria (the cells energy powerhouse), the pathways by which glucose was further broken down to produce energy were very different in macrophages without a clock. This led to the production of reactive oxygen species (ROS) which further fuelled inflammation. 

Dr George Timmons, lead author on the study, said: “Our results add to the growing body of work showing why disruption of our body clock leads to inflammatory and infectious disease, and one of the aspects is fuel usage at the level of key immune cells such as macrophages.” 

Dr Annie Curtis, Senior Lecturer at RCSI School of Pharmacy and Biomolecular Sciences and senior author on the paper, added: “This study also shows that anything which negatively impacts on our body clocks, such as insufficient sleep and not enough daylight, can impact on the ability of our immune system to work effectively.”

RCSI conducted the study in collaboration with researchers from Swansea University, Trinity College Dublin and University of Bristol. 

About this inflammation and circadian rhythm research news

Author: Rosie Duffy
Source: RCSI
Contact: Rosie Duffy – RSCI
Image: The image is in the public domain

Original Research: Open access.
The Circadian Clock Protein BMAL1 Acts as a Metabolic Sensor In Macrophages to Control the Production of Pro IL-1β” by George Timmons et al. Frontiers in Immunology


Abstract

The Circadian Clock Protein BMAL1 Acts as a Metabolic Sensor In Macrophages to Control the Production of Pro IL-1β

The transcription factor BMAL1 is a clock protein that generates daily or circadian rhythms in physiological functions including the inflammatory response of macrophages. Intracellular metabolic pathways direct the macrophage inflammatory response, however whether the clock is impacting intracellular metabolism to direct this response is unclear. Specific metabolic reprogramming of macrophages controls the production of the potent pro-inflammatory cytokine IL-1β.

We now describe that the macrophage molecular clock, through Bmal1, regulates the uptake of glucose, its flux through glycolysis and the Krebs cycle, including the production of the metabolite succinate to drive Il-1β production.

We further demonstrate that BMAL1 modulates the level and localisation of the glycolytic enzyme PKM2, which in turn activates STAT3 to further drive Il-1β mRNA expression. Overall, this work demonstrates that BMAL1 is a key metabolic sensor in macrophages, and its deficiency leads to a metabolic shift of enhanced glycolysis and mitochondrial respiration, leading to a heightened pro-inflammatory state.

These data provide insight into the control of macrophage driven inflammation by the molecular clock, and the potential for time-based therapeutics against a range of chronic inflammatory diseases.

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  1. Dear Federal Morado,

    Don’t be bulldozed by the time shifts, You can start a few days early, moving your clocks a quarter of an hour a day, adjusting gradually; so that your and your circadian rhythms don’t fall too far out of sync. I know, it is a shock when the sun suddenly disappears too early in the afternoon, but we’ve learned to compensate for that with our reliable electric lights. So don’t fight it: learn to work your way around it!

  2. While I am by no means an authority on any level of Medicine, I have always believed I was programmed cyclic ly and early on recognized I was very much in since with our universe, thereby beluving in the fact or idea that I am capable of healing myself and this through mental focus or belief in the ability to do so.. Any thoughts on this?

  3. I really hope researchers and doctors can keep in mind that depression and anxiety caused by corporate greed where workers don’t often get raises or wages that keep up with inflation is a huge contributor. 75% of Americans are living paycheck to paycheck and there are like 8 billionaires that have more money than millions of people’s income combined. We can’t reduce depression and anxiety without addressing homelessness, poverty, the price of retirement ans that the average person’s annual income in a lot of major cities is around 50k while the average home costs 250k-300k.

  4. I don’t know what’s wrong with me but I sleep CONSTANTLY. Sometimes, even after a solid 10-12 hours asleep I cannot even move my body as I feel I’m drugged. Brushing my teeth is too much effort. I can sleep for 24-48 hours with very brief periods of wakefulness. I use this time to try to eat something as I eat very little but-as soon as I eat anything remotely substantial-I pass out for hours again and again, can barely move when I briefly awaken. I do have hypothyroidism and take levothyroxine but although they say my T3 and T4 levels are fine I don’t feel any better. Could depression be causing this? I’ve always struggled but was an organized, sharp spitfire until the thyroid problem in my late 40’s, early 50’s. Reading articles like this literally scare the hell out of me, and I’ve been seeing more like it daily.

  5. Great piece of research. We knew from sleep studies and use of digital TOS that this has an effect on sleep, behaviour and wellbeing, you have added another critical layer of understanding to this.

  6. One might also note the instantaneous disruption of circadian rhythms due to time fluctuations caused by the use of “daylight savings time”. It takes considerable time for most bodies to adjust to having our clocks turned forward or backward , all for that extra hour if daylight that has failed to deliver on its promises of money saving to extra rounds of golf. Let us stay in one time zone please!

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