Expression of cytokines by multipotent neural progenitor cells.

Recent work with mammalian neural stem cells has highlighted the role of cytokine signaling in the proliferation and differentiation of these multipotent cells. While the responsiveness of neural progenitors to exogenously applied growth factors has been demonstrated in vivo as well as in vitro, little attention has been given to the production of cytokines by these cells. Here we use immunocytochemistry, RT-PCR, and ELISA to show that under standard growth conditions multipotent neural progenitor cells from humans express multiple cytokines including IL-1alpha, IL-1beta, IL-6, TGF-beta1, TGF-beta2, TNF-alpha, but not IL-2, IL-4, or IFN-gamma. Neural progenitor cells from rat and mouse express some, but not all, of these cytokines under similar conditions. While the function of cytokine expression by neural progenitor cells remains to be elucidated, these signaling molecules are known to be involved in neural development and may play a role in the activation of quiescent stem cells by a variety of pathological processes.