Mount Sinai Logo Microglia, the immune cells living within the brain are known to be vital in the development of many brain diseases. Defective microglia probably results in the release of inflammatory molecules that are involved in the development of degenerative brain diseases. Scientists from Mount Sinai claim that microglia have a novel origin and are formed shortly after conception. The research findings can probably open door to future treatments of degenerative brain diseases like Alzheimer’s and autoimmune diseases such as multiple sclerosis.

Most scientists believed that microglia originated at the same time as macrophages, which are other immune cells developed at birth. Claimed to be a novel research, investigators transplanted blood cell precursors of macrophages from one newborn mouse to another. It was observed that the transplanted cells were seemingly unable to be distinguished in the recipient animal. So microglia may be originating before birth during embryonic life itself. A mouse model expressing fluorescent biosensors in blood precursors were employed for ascertaining when, during embryonic age, precursors develop into microglia. When the fluorescence gets activated it may not go away and all cells developed from the fluorescent precursors remain fluorescent.

Miriam Merad, MD, PhD, Associate Professor of Gene and Cell Medicine at Mount Sinai School of Medicine and lead investigator, highlighted, “This really is a startling discovery. 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 embryonic stem cells 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.”

Scientists claim to have activated the fluorescence seven days after conception. While analyzing adult mice, experts were able to discover fluorescent microglia but not fluorescent macrophages. It was concluded that microglia are novel for their origin from precursors coming up almost seven days after conception. Additional investigations will be undertaken to examine whether normal development of precursor blood cells into microglia can help analyze the role of microglia in various brain diseases and ultimately lead to advances in treatments.

The research was published online on October 21 in Science Express.