Dopamine derivatives from the insect Polyrhachis dives as inhibitors of ROCK1/2 and stimulators of neural stem cell proliferation

Polyrhachis dives is consumed as an insect food in some regions of China. In this study, new dopamine derivatives, (+)-polyrhadopamine A (1a) and (−)-polyrhadopamine A (1b), (+)-polyrhadopamine B (2a) and (−)-polyrhadopamine B (2b), and polyrhadopamines C–E (3–5), were isolated from this species. The structures and stereochemistry of these substances were assigned by using spectroscopic and computational methods. Compounds 1a, 1b, 2a, and 2b are dimeric N-acetyldopamine derivatives, 3 is a dopamine analog containing an unusual sulfone group, and 4 and 5 possess a rare benzo[d]thiazole moiety. The functions of these substances as ROCK1/2 inhibitors, neural stem cell (NSCs) proliferation stimulators, immunosuppressive, and anti-inflammatory agents were determined.     

The Synergistic Effect of Cationic Moieties and GRGDSF‐Peptides in Hydrogels on Neural Stem Cell Behavior

This article reports the behavior of embryonic neural stem cells on a hydrogel that combines cationic, non‐specific cell adhesion motifs with glycine‐arginine‐glycine‐aspartic acid‐serine‐phenylalanine (GRGDSF)‐peptides as specific cell adhesion moieties. Therefore, three hydrogels are prepared by free radical polymerization that contains either a GRGDSF‐peptide residue ( P1 ), amino ethylmethacrylate as a cationic residue ( P2 ), or a combination of both motifs ( P3 ). For each gel, cross linker concentrations of 8 mol% is used to have a comparable gel stiffness of 8–9 kPa. The cell experiments indicate a synergistic effect of the non‐specific, cationic residues, and the specific GRGDSF‐peptides on embryonic neural stem cell behavior that is especially pronounced in the cell adhesion experiments by more than doubling the number of cells after 72 h when comparing P3 with P2 and is less pronounced in the proliferation and differentiation experiments.