Researchers discover origin of immune cells in the brain

Oct 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.

Explore further: Scientists find new calorie-burning switch in brown fat

Provided by The Mount Sinai Hospital

3.9 /5 (8 votes)

Related Stories

How does microglia examine damaged synapses?

Mar 31, 2009

Microglia, immune cells in the brain, is suggested to be involved in the repair of damaged brain, like a medical doctor. However, it is completely unknown how microglia diagnoses damaged circuits in an in vivo brain. Japanese ...

Blocking toxic effects could make clot-buster safer

Jan 23, 2009

Since the introduction of the life-saving clot-busting drug tPA more than a decade ago, evidence has been accumulating that tPA (tissue-type plasminogen activator) can be a double-edged sword for a brain affected by stroke. ...

Researchers identify a cell type that limits stroke damage

Jan 27, 2009

A research team including Serge Rivest of University Laval's Faculty of Medicine has demonstrated the existence of a type of cells that limits brain damage after a stroke. The study was recently published in the online version ...

Recommended for you

Clues to curbing obesity found in neuronal 'sweet spot'

8 hours ago

Preventing weight gain, obesity, and ultimately diabetes could be as simple as keeping a nuclear receptor from being activated in a small part of the brain, according to a new study by Yale School of Medicine ...

Small RNAs in blood may reveal heart injury

18 hours ago

(Medical Xpress)—Like clues to a crime, specific molecules in the body can hint at exposure to toxins, infectious agents or even trauma, and so help doctors determine whether and how to treat a patient. ...

User comments : 0