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Stem Cell Umbrellas

June 19, 2018

Pigmented cells shade blood producing cells from sun damage in the kidneys of fish.

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In a zebrafish larva, a dark umbrella formed by pigmented cells (white arrows point to these black spots in box, left) in the kidney protects vulnerable stem cells from damaging UV light. Right image is a closeup of the box. Scale bars equal 100 micrometers (left) and 50 micrometers (right). (F. Kapp et al./Nature 2018)

In a zebrafish larva, a dark umbrella formed by pigmented cells (white arrows point to these black spots in box, left) in the kidney protects vulnerable stem cells from damaging UV light. Right image is a closeup of the box. Scale bars equal 100 micrometers (left) and 50 micrometers (right). (F. Kapp et al./Nature 2018)

BOB HIRSHON (host):

Shading stem cells. I’m Bob Hirshon and this is Science Update.

Ultraviolet radiation from sunlight kills the stem cells that form new blood cells. In fish, blood cells are produced in the kidneys. Now, a study in the journal Nature describes how pigment cells called melanocytes protect blood stem cells in fish by shading their kidneys from harmful UV rays. Harvard biologist Leonard Zon says when exposed to artificial radiation, the melanocytes of normal fish shielded the stem cells. But mutant fish that were missing melanocytes suffered stem cell damage.

LEONARD ZON (Harvard University):

So it definitely showed that there was a radiation sensitivity to the blood stem cells, and the melanocytes were there to protect them.

HIRSHON:

In humans, blood cells are formed in the bone marrow, far from UV rays. But the findings could contribute to better ways of protecting vulnerable stem cells during bone marrow transplants. I’m Bob Hirshon, for AAAS, the science society.

Story by Susanne Bard