Samantha Butler, Ph.D. 

Samantha Butler, Ph.D., studies how the nervous system — the complex network made up of the brain, spinal cord and nerves that run through the body — connects and grows during fetal development. The extraordinarily diverse functions of the nervous system include voluntary and involuntary movement, memory and decision-making and processing information from the five senses. Butler’s work primarily focuses on understanding the mechanisms that establish neural circuitry in the spinal cord to regenerate the nerves that let us sense the environment. These vital functions, such as pain and touch, can be lost due to injuries that sever nerves or cause paralysis as well as diseases that damage nerves such as diabetic neuropathy. Although progress has been made in developing treatments to improve motor function for patients with nerve damage, the same cannot be said for treatments to reestablish sensory abilities, such as those that enable an individual to feel comforted by a reassuring squeeze from a loved one or flinch away from a hot surface to avoid being burned. By pursuing greater understanding of how the nervous system develops, Butler hopes to identify methods that use stem cells or drugs to replicate normal development and regenerate damaged or diseased nerves and nerve connections.

Butler’s work overturned a long-standing paradigm about how axons — thread-like projections that connect cells in the nervous system — grow during embryonic development. Contrary to long-held understanding, Butler discovered that neural progenitors, tissue-specific stem cells that can create any cell type in the nervous system, organize axon growth by producing a pathway of a protein called netrin1 that leads them through their local environment. This insight into axon growth could enable scientists to use netrin1 to regenerate axons in patients with serious nerve damage, such as veterans with combat injuries. Without intervention, these patients face lengthy and painful recovery times, and can lose both movement and sensation in the injured limb due to the gradual loss of nerve cells after injury. Butler hopes to identify ways in which netrin1 can be used to stimulate the rapid regrowth of peripheral nerves, resulting in faster recovery times for patients with nerve damage.

Butler also seeks to identify the ways in which stem cells can be used to repair damaged or abnormal sensory neurons, which are responsible for sense of touch and the ability to feel pleasure and pain. Sensory neurons can be damaged by physical trauma or injury, chemotherapy, autism, aging or other diseases. By identifying how stem cells become spinal sensory neurons during fetal development, Butler has been able to reproduce this process and define methods for making different classes of sensory spinal neurons from stem cells. In her most recent work, Butler has found that these stem cell-derived neurons mirror their naturally occurring counterparts in the embryo to a remarkable extent — setting the stage to use these lab-created sensory neurons for effective cellular therapies that restore sensory function to injured patients.

Butler earned a doctorate in molecular biology from Princeton University and completed a postdoctoral fellowship at Columbia University.