Microglia in Mice and Men

A hot debate has broken out among scientists who study microglia, the glorious cells best known as the soldiers of the brain’s immune system. OK, “debate” may be a strong word; it’s really just a series of gentlemanly letters published over the last couple of months in a neuroscience journal you’ve probably never heard of. Still, I think the debate is worth highlighting not only because I’m an unabashed fan of microglia, but because it raises one of the most pressing issues facing medical research: the differences between mice and people.Microglia straddle the fields of immunology and neuroscience. The cells begin in the yolk sac as part of the immune system, in the same cellular lineage as the macrophages of the blood. But over the first week of life, microglia migrate to the brain and make it their permanent home. They become vigilant soldiers, constantly patrolling for any sort of cellular invader, whether a bacterial infection or a pile of protein trash. Once they spot the offender, they snap into action, morphing from their spindly resting state into a fat blob so they can literally eat the problem.Microglia’s role in the immune system has been known for more than a century. But the cells’ popularity skyrocketed in the last decade or so, after being linked to neurodegenerative disease, developmental disorders, and plasticity in the healthy brain. The vast majority of these microglia studies rely on laboratory mice. And that’s not good, according to neuroscientists Amy Smith and Mike Dragunow.Read more at...Only Human, April 2014.