Biological complexity: the brain hwlps fight infections (Introduction)

by David Turell , Friday, January 27, 2017, 01:22 (2858 days ago) @ David Turell

The brain releases helper proteins to activate immunity active dells such as macrophages:

https://cosmosmagazine.com/biology/how-the-brain-helps-the-body-fight-bacteria?utm_sour...

"The brain may not only control our thoughts and basic physical functions. Recent studies indicate that it also controls the way our body responds to the threat of bacterial infections. It does this by boosting the production of a protective molecule called PCTR1 that helps white blood cells kill the invading bacteria.

"To identify novel avenues to treat bacterial infections we turned our focus to the central nervous system (the brain, spinal cord and optic nerves), as several studies have implicated the brain in orchestrating more than just our thoughts. In our study we found that severing the right vagus nerve in mice, for example, leads to a significant impairment in their ability to clear E. coli infections.

"When we investigated the reason for this delay, we found a significant decrease in the levels of a molecule called “protectin conjugate in tissue regeneration 1”, or PCTR1 for short. PCTR1 is part of a group of molecules called specialised pro-resolving mediators that control how our body responds to inflammation. It is produced by white blood cells from a fish oil-derived essential fatty acid called docosahexaenoic acid.

"We also found that the decrease in PCTR1 reduced the ability of macrophages – a type of white blood cell – to kill E. coli.

"We then investigated how the vagus nerve regulates PCTR1 production in the abdominal cavity of the mice, where this nerve is known to regulate white blood cell behaviour during inflammation. Here we found that the nerve releases a neurotransmitter called acetylcholine which then instructs another type of immune cell (innate lymphoid cells) to increase production of PCTR1. This in turn regulated macrophages’ ability to find and kill bacteria.

'When we injected the mice with the severed vagus nerve with PCTR1, we found that it restored the ability of peritoneal macrophages to get rid of the bacteria as well as dampen the subsequent inflammatory response, accelerating the bacteria’s termination.

"These results are expected to have wide-ranging implications in the fight against bacterial infections, especially in light of the alarming rate at which bacteria are becoming resistant to antibiotics. This is because these findings demonstrate that we can give our body a hand by using PCTR1, and related molecules, to enhance its ability to clear bacteria during infections, reducing our reliance on antibiotics."

Comment: How did evolution develop this setup? Looks designed to me since we are dealing with the brain watching over the presence of infection and producing a specific hormone to support the cells' actions. It certainly looks irreducibly complex.