GDNF and amyotrophic lateral sclerosis: In another study, neural progenitor cells that were manipulated to overexpress glial cell-line derived neurotrophic factor (GDNF) enhanced the survival of MNs survival and attenuated the progression of the disease phenotype after their injection into the spinal cord (Klein et al., 2005) or motor cortex (Thomsen et al., 2018) of ALS rat model.