BDNF and amyotrophic lateral sclerosis: Furthermore, Liao et al. observed increased mRNA levels of the M2 phenotype markers Ym1, CD163 and BDNF in murine mSOD1 microglia during the early stages of ALS, suggesting that microglia express the M2 anti-inflammatory phenotype during the early stages of ALS (Liao et al., 2012).