Rebuilding the brain: The Morshead Lab’s mission to awaken neural stem cells

When Morshead was beginning her scientific career, this consensus was still absolute. However, a series of landmark discoveries ultimately proved that the adult central nervous system harbours neural stem cells: versatile, unspecialized cells capable of self-renewing and converting into specific cell types like neurons. 

“Finding stem cells in the adult brain was earth-shattering for the whole stem cell biology field,” says Morshead. “At the time, we were asking, ‘Why would we have stem cells in the brain, this non-reparative structure that we were all taught couldn't get neurons back?’” 

Thus ensued a rapid evolution in regenerative medicine. Early efforts focused on transplanting stem cells grown in large scale bioreactors. However, direct cell transplantation encountered significant clinical hurdles such as immune rejection and tumorigenesis risks. The broader field adapted once more as embryonic stem cell debates gave way to induced pluripotent stem cells (iPSCs), and eventually to direct lineage reprogramming where the brain’s ordinary supporting cells (known as glia) were converted into neurons. 

For Morshead’s lab, the most promising therapeutic paradigm lay not in transplanting donor cells, but in leveraging the repair machinery already residing within the brain. Rather than harvesting, expanding, and re-injecting external cells into injured tissue, Morshead focused on a paradigm she calls “healing from within”: stimulating the brain’s existing stem cell reserves tucked away in specialized regions.  

“We’re interested in getting the brain to heal itself without having to do transplantation,” Morshead explains. “Let’s stimulate the endogenous repair mechanisms in the brain.” 

To accelerate clinical translation, Morshead’s group turned to drug repurposing by evaluating existing FDA-approved pharmaceuticals with well-characterized safety profiles. Her lab demonstrated that metformin, a widely prescribed diabetes medication, can foster functional tissue repair across rodent models of neural injury.   

Beyond prompting stem cells to divide and generate new brain cells, her lab uncovered that metformin’s therapeutic benefits are closely linked to the surrounding immune microenvironment. Morshead’s team showed that the physical presence of neural stem cells is necessary to calm brain inflammation following injury. This established a vital link between endogenous stem cells and neuroinflammation suppression.   

In addition to pharmacological approaches, Morshead’s lab has pioneered bioengineering methods that use applied electric fields to direct stem cell behaviour in vivo. Applying targeted electric fields prompts resident precursor cells to migrate out of their neurogenic niche toward sites of injury. Crucially, Morshead emphasizes the intrinsic safety controls of this approach: while the electric field causes cells to proliferate and migrate, removing the stimulation causes them to stop, preventing uncontrolled growth. 

Bridging the gap between bench discovery and human trials requires solving complex biological barriers long before clinical testing can even begin. Even after uncovering the underlying biology, researchers face the steep logistical and financial roadblocks of launching human clinical trials.   

“The biggest bottleneck is money,” Morshead explains. “What you need is a champion: a clinician-scientist who says, ‘Yeah, this is a good idea, I would bring this to my patients.’ Finding that champion, along with the dense research network we have in Toronto and at the Donnelly Centre, makes bringing these technologies forward feasible.” 

This collaborative ecosystem has reshaped modern scientific inquiry. Today, high-impact translational science relies on interdisciplinary integration. Morshead’s lab exemplifies this approach by combining stem cell biology with tissue and biomaterial engineering through collaborations with researchers such as Molly Shoichet (Department of Chemical Engineering & Applied Chemistry and the Donnelly Centre). The lab also integrates computational methods and clinical medicine, further strengthening their interdisciplinary approach. 

Looking to the future, Morshead sees the intersection of neural stem cell research and clinical neurology being shaped by targeted gene therapies and engineered, immune-evasive stem cell platforms.  

“We are learning so much about how stem cells respond to treatments using patient cells and organoids,” Morshead reflects. “All of those insights will guide novel technologies and gene therapies to make regenerative neurology a clinical reality.”