CDKN1B and Parkinson disease: Lumbricusin, an 11-merantibacterial peptide (NH2-RNRRWCIDQQA) isolated from earthworms, significantly increases the proliferation of mouse neural stem cells (MNSCs) isolated from the mouse brain, enhances proteasome-mediated p27Kip1 degradation in MNSCs, protects MNSCs against 6-hydroxydopamine-induced apoptosis, and attenuates motor impairments in the PD mouse model (15).