Monday, October 3, 2022

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Deadly Mushroom Can Change Shape Deep In Your Brain: ‘Shocked’

A fungus that can change shape to fit your brain has been discovered by scientists.

Cryptococcus neoformans (C. neoformans), a pathogenic fungus, can transform itself to pass through the blood-brain barrier, a protective layer used to prevent pathogens from entering the brain, according to an article published in the journal Cell host and microbe.

“The changes it goes through when it first enters the body are pretty amazing and we’re still trying to figure it out,” said University of Utah pathologist and co-author Jessica Brown. ‘article. Pleasemynews.

C. neoformans can be found in the wild living on rotting wood or in bird droppings. According to the CDC, if the fungus is inhaled, it can infect the lungs and other organs, including the brain, resulting in cryptococcal meningitis.

The researchers found that the smallest cells of C. neoformans ended up in the brains of the mice they studied, and that the surface area of ​​these small cells changed as they entered the brain.

“Cryptococcus cells in the lungs are very diverse with different sizes and appearances. So when my graduate student showed me images of brain cell uniformity, I was shocked,” Brown said. in a press release.

“We demonstrate that the formation of a small morphotype of C. neoformans, termed ‘seed’ cells because of their colonizing ability, is essential for extrapulmonary entry into organs,” the authors write in the paper. “Seed cells exhibit changes in fungal cell size and surface expression that result in enhanced macrophage updating.”

These seed cells have an altered cell surface that causes them to be taken up by macrophages (immune cells), according to Brown.

“In a number of tissues, macrophages are responsible for containing invaders, so they will pick them up and attempt to sequester and destroy the invader,” she said.

“We think the seed cells exploit this tendency, are transported more easily by the macrophage into the organ, and then escape and grow in their new organic environment if the conditions are right, as they are in the brain.”

According to Brown, after a seed cell enters the brain, the first type of cells to form are called titan cells because they are gigantic, containing at least four times as many copies of DNA as a cell. “normal” of C. neoformans.

“These titanium cells form directly from the infection [seed] cells,” Brown said. Pleasemynews. “The seed cells we’re studying, the little ones that enter the brain, probably don’t form when another cell shrinks.

“Instead, we believe that seed cells form through generations: a normal or titan cell receives a signal, then when it then divides to form a new cell, it makes a seed cell like its offspring at the instead of a cell as itself. The seed Cells then probably form more germ cells when they divide.”

The fungus has already been found to increase its cell mass by up to 10 times inside the human lung, so the fact that it can enter the brain is concerning.

“The scary thing about this fungus is that we don’t think it wants to enter the brain per se,” Brown said. “It doesn’t pass from person to person, so there’s really no evolutionary selection to develop inside a person like there is with, for example, viruses. respiratory.

“Instead, we think it’s an evolutionary accident. C. neoformans thrives extremely well on inositol, which is found in high amounts in the cerebrospinal fluid, spinal cord, and brain. brain tissue. This could be a result of C. neoformans’ natural environment, which is soil, trees, and bird droppings, as plant material is high in inositol.”

“So we believe that C. neoformans has acquired the ability to grow on inositol in its environmental niche and that this ability ends up being problematic when people are infected, because when C. neoformans reaches the inositol-rich central nervous system , he is developing well and there is not much to prevent him from doing so.”

Researchers fear that the effects of climate change could make C. neoformans more effective at infecting humans.

“A concern in the future is that as the climate changes, microbes such as fungi will become more adapted to stressful conditions (extreme temperatures, drought, etc.) which will increase their ability to survive stressful conditions in the body. human,” Brown said. said.

However, the researchers also hope their discovery could lead to new strategies for blocking C. neoformans infection.

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