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Human Health

Attacking Alzheimer’s: Medicinal marine microbes

From: Muralidharan, Anuraag, et al. “Exploring the Potential of Marine Microbes in Clinical Management of Alzheimers Disease: A Road Map for Bioprospecting and Identifying Promising Isolates.” Life Sciences, vol. 208, 2018, pp. 149–160., doi:10.1016/j.lfs.2018.07.036.

The problem with Alzheimer’s

It is important to protect our brains. They are vital to our survival.
From: Science X. “Brain Encodes Time and Place of Taste Memory.” medicalxpress.com/news/2014-09-brain-encodes-memory.html.

Globally, Alzheimer’s disease (AD) is becoming more common and takes a large toll on our elderly populations. AD destroys neurons, the cells in the brain that send electrical signals to the nerves in our bodies. Without these functioning neurons, dementia can develop, causing a variety of symptoms, commonly including memory loss and a decreased function of overall understanding. Available medicines on the market today only deal with the symptoms of AD and not with the root cause (neuronal breakdown). That’s why researching new sources of medicinal compounds capable of specifically targeting the damage to the brain are in high demand. One of the hottest areas of research for new pharmaceuticals are microbes in the ocean. These marine bugs could provide the missing link for managing and curing AD.

Is there medicine in the ocean?

70% of the life in the ocean is made up of microbes! Most active drug compounds come from metabolites, or by-products of an organism’s metabolism. Significant portions of the metabolites already used in prescription medications come from microbes that were found in the ocean via bioprospecting (the search for medical metabolites in natural habitats). Marine microorganisms have a high prevalence of medicinal metabolites, partly because many of them evolved to live in a wide range of extreme environments, such as the deep ocean or in the Arctic Circle. This forces evolution of diverse metabolisms, thereby creating novel metabolic by-products.

Glutamate (neurotransmitter). (2018, August) From: https://en.wikipedia.org/wiki/Glutamate

Despite many metabolites having already been found here, the ocean remains the least studied habitat on Earth. The marine environment likely contains a large pool of new drugs ready to be discovered. The most common AD medications work by decreasing symptoms, including allowing neurons to continue creating their electrical signals. This is achieved by slowing down the breakdown of acetylcholine, a compound that helps nerves function and is destroyed faster in Alzheimer’s patients. Another type of AD drug is an NMDA receptor antagonistthat stops the interaction of glutamate(a neurotransmitter that helps send signals from one nerve to another) and the NMDA receptor (a spot on nerve cells that glutamate attaches to). Although glutamate is required for signaling, it can have over excitation and toxic effects on nerve cells when it is attached for too long. NMDA receptor antagonists work by reducing that toxicity. Both of these drugs only attempt to reduce the symptoms of AD instead of working to reduce the neural damage in the first place.

Deep sea black smokers are hotspots for finding new microbial metabolisms.
From: Portland State College of Liberal Arts & Sciences: Deep Sea Black Smoker, Atlantis Massif (n.d.). https://www.pdx.edu/extreme-environments/

Muralidharan et al.found that the most common source of damage that causes the initial memory loss are deposits of amyloid plaques, toxic levels of the proteins amyloid-betaand ß-secretase that cause neuron damage and kill brain cells. Reducing these two protein levels is an important focus for future drug development. There are a few studies that show that marine metabolites from microorganisms (algae, bacteria, or fungi) helped reduce the concentrations of both amyloid-beta and ß-secretase in the lab. Exploring marine environments—especially more extreme regions—could provide many new drugs that tackle the problem of these high protein concentrations.

Future focus

As the proportion of elderly people in the global population continues to rise, so does the number of AD cases. In order to lengthen the lifespan and elevate living conditions of our aged citizens, it is vital that we find ways to stop the effects of Alzheimer’s before they begin. Novel metabolites are surely hiding in the world’s ocean, and in order to find them a methodical sampling of ocean microbes has to be done. A specific focus should be given to extreme environments where the largest proportion of current marine medicines have been found. Continued research into metabolites that decrease the concentrations of amyloid-beta and ß-secretase will not only decrease the likelihood of developing life-threatening AD, but could also save millions in healthcare investment around the globe. This research leaves open the question, what other diseases might be treated through bioprospecting?

 

 

I am a Master’s Candidate at University of Delaware where I study the evolution of microbes in the sediments where rivers meet the ocean. Organisms in these sediments, Asgard archaea, could be the link between early microbes and the evolution of advanced life: AKA everything you can see with your eyes! Outside of biology, I love to write. I even wrote for a music magazine in my home town for 6 years. Writing for Oceanbites provides an opportunity to combine my passion for science with my zeal for writing. When I’m not in the lab, I am outdoors, whether its running a nature trail, backpacking, or rowing with my team.

Discussion

One Response to “Attacking Alzheimer’s: Medicinal marine microbes”

  1. Great article – very understandable. Good luck with your research!

    Posted by Todd Wheeler | September 20, 2018, 9:34 am

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