Researchers discover origin of immune cells in the brain

October 22, 2010

Mount Sinai researchers have discovered that microglia, the immune cells that reside in the brain, have a unique origin and are formed shortly after conception. It was previously thought that microglia originated at the same time as macrophages, which are other immune cells that are thought to develop at birth. This groundbreaking discovery has the potential to lead to future treatments of degenerative brain diseases such as Alzheimer's and autoimmune diseases such as multiple sclerosis. The study is published online October 21 in Science Express.

Microglia are thought to play an important role in the development of many brain diseases, and that defective microglia could lead to the release of inflammatory molecules, which could participate in the development of degenerative brain diseases.

"This really is a startling discovery," said Miriam Merad, MD, PhD, Associate Professor of Gene and Cell Medicine at Mount Sinai School of Medicine and Principal Investigator of the study. "We've shown that the precursor cells develop into microglia only during a short period after conception. Now that we know that microglia originate in early embryos, theoretically we should be able to generate microglia from to treat brain diseases caused by defective microglia. This is a very good example of why scientists need to be able to conduct research with embryonic stem cells."

For the first part of the study, researchers transplanted blood cell precursors, which are precursors for all macrophages, from one newborn mouse to another. The transplanted cells could not be differentiated in the recipient animal. These results suggest that microglia originated prior to birth during embryonic life.

Next, researchers used a that expresses fluorescent biosensors in blood precursors to determine when, during embryonic age, precursors develop into microglia. Once activated the fluorescence does not go away and all cells that develop from the fluorescent precursors should remain fluorescent. The researchers activated the fluorescence as early as seven days after
conception. When they examined adult mice they found fluorescent microglia but no fluorescent . These results established that microglia are unique in that they originate from precursors that arise around seven days after conception.

"Moving forward we need to further study the normal development of precursor blood cells into microglia, which should help identify the role of microglia in various brain diseases and ultimately lead to advances in treatments," said Dr. Merad.

Related Stories

Recommended for you

Artificial beta cells

December 8, 2016

Researchers led by ETH Professor Martin Fussenegger at the Department of Biosystems Science and Engineering (D-BSSE) in Basel have produced artificial beta cells using a straightforward engineering approach.

Key regulator of bone development identified

December 8, 2016

Loss of a key protein leads to defects in skeletal development including reduced bone density and a shortening of the fingers and toes—a condition known as brachydactyly. The discovery was made by researchers at Penn State ...

Researchers question lifelong immunity to toxoplasmosis

December 8, 2016

Medical students are taught that once infected with Toxoplasma gondii—the "cat parasite"—then you're protected from reinfection for the rest of your life. This dogma should be questioned, argue researchers in an Opinion ...

TET proteins drive early neurogenesis

December 7, 2016

The fate of stem cells is determined by series of choices that sequentially narrow their available options until stem cells' offspring have found their station and purpose in the body. Their decisions are guided in part by ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.