Until recently, most scientific knowledge about amyotrophic lateral sclerosis (ALS), better known as Lou Gehrig’s disease, came from mouse studies. But new research is taking this incurable neurodegenerative condition to the dish, tapping induced pluripotent stem cells (iPS cells)—made from ALS patients’ skin cells—to create motor neurons. These motor neurons are being used not just to model how ALS works at the cellular level but also to screen potential drugs.
Translational neuroscience research has seen a disappointing streak of failed clinical drug trials. While the need for therapeutics that target the nervous system is growing, recent results in diseases like Alzheimer’s and autism have disappointed, and many companies have begun to downsize their R&D investments. Prospects are glum for patients who need new therapies to help manage their disorders.
The frustration is that drug candidates that have shown promise in animal models have not demonstrated efficacy in humans. Mouse models are not proving to be sufficient surrogates for human neurologic disease. Human brains and brain cells are built and function differently, and many neurodevelopmental disorders—hard enough to diagnose in human children—don’t have identifiable behavioral counterparts in mice. As I hear over and over from scientists, there is no such thing as a mouse with autism.
The above movie shows an immune cell caught in the act of tending the brain—it’s just eaten away unnecessary connections, or synapses, between neurons.
That’s not something these cells, known as microglia, were previously thought to do. As immune cells, it was thought that their job was to rid the body of unwanted pathogens and debris, by engulfing and digesting them.