The role of interleukin-6 (IL-6) in the proliferation and differentiation of human neural stem cells

The proliferation of human embryonic and adult stem cells is controlled by extrinsic factors such as epidermal growth factor (EGF) and fibroblast growth factor (bFGF). Their differentiation, instead, is clearly determined by a family of neuropoietic factors including ciliary neurotrophic factor (CNTF), leukaemia inhibitory factor (LIF) and interleukin-6 (IL-6). The results of this study show the capability of the interleukin-6 to delay the differentiation processes and to improve significantly the proliferation condition of embryonic neural stem cells. Besides, clonal analysis shows that the self-renewing capacity and the multipotentiality of human embryonic neural stem cells are not modified by the presence of IL-6 during early and later culture passages. This is an important demonstration of the high clonogenic potential of IL-6 in human embryonic neural stem cells (heCNS-SC), whose capacity to secrete IL-6 we have, finally, demonstrated.