Brain cells grown by a molecular 'cocktail' in the lab.

Harvard researchers reported a set of molecular signals that converted cortical NG2 progenitor cells in vitro into corticospinal neurons, producing a lab model of the cells affected in ALS and spinal cord injury.

Harvard stem cell researchers reported a laboratory method that coaxed a subtype of cortical progenitor cells to become corticospinal neurons, the brain cells involved in voluntary motor control. These neurons are the ones that degenerate in amyotrophic lateral sclerosis (ALS) and can be damaged in spinal cord injury. The work was reported in the journal eLife and was carried out in cell cultures rather than in living animals. Researchers describe the method as a first-generation approach that can be refined. Key facts: - The team used a combination of molecular signals to reprogram SOX6+/NG2+ cortical progenitor cells into cells that resemble corticospinal neurons. - The lab-grown cells showed morphological, gene-expression, and electrophysiological features reported as consistent with corticospinal neurons. - The result was demonstrated in vitro only; the study did not show regeneration in living animals or humans. - The researchers reported plans to test and refine the approach in animal models, with experiments in mice anticipated within a few years. Summary: The study provides a new laboratory model for corticospinal neurons, which may aid research into diseases that selectively affect those cells, such as ALS, and injuries that damage their long axons. Further work will assess whether the method can be adapted to living animal brains and to human stem cell–derived cells; timelines are reported as preliminary and under development.