Jocelyn Breton and Yang Mao-Draayer
Neural stem/progenitor cells (NSC/NPC) can be a powerful tool for the neural repair of the damaged brain. Many of the current challenges with stem cell therapies revolve around the problem that stem cells do not survive, migrate, proliferate and differentiate as much as hoped. Understanding the interaction between NPCs and the immune system is essential for the effective use of stem cell transplantation. Cytokines play an important role in determining the inflammatory microenvironment and have also been shown to have effects on the differentiation, proliferation, migration and survival of NPCs. The effects of cytokines on neural stem cell fate is more complex than once believed; the distinction between anti-inflammatory and pro- inflammatory cytokines is not straightforward and varies based on conditions such as cytokine concentration and area of transplantation. If their role is understood, cytokines could be used to improve the efficacy of stem cell treatments and enhance neural repair. In this review, we provide a comprehensive overview of the effects of various cytokines on NPC fate. The ultimate goal of this review is to demonstrate how manipulation of the CNS microenvironment through alteration of various cytokines can enhance the capacity of NPC differentiation, proliferation, and overall neural repair.