BDNF and Cowden syndrome 1: In the spinal cord, GT1b acts as an endogenous agonist of toll like receptor 2 of microglia, activates the P38 MAPK pathway, and induces microglia to secrete IL‐1β, TNF‐α, brain‐derived neurotrophic factor (BDNF) and nitric oxide (NO) production, which in turn leads to CS (Lim et al., 2020; Liu et al., 2017).