Division of labor in neural stem cell maintenance

Numerous soluble proteins and receptors help to maintain neural stem cells' (NSCs) supportive environment in central nervous system (CNS). NSCs access some of these nurturing factors by sending cellular extensions into the cerebral spinal fluid (CSF), which is rich in stem cell-promoting proteins.

Insulin-like growth factors (IGF-I and IGF-II) are essential for the growth and development of the CNS. But although they are abundant in the brain and CSF, it was not clear whether they are required by NSCs. Steven Levison, PhD, and Teresa Wood, PhD, of UMDNJ-New Jersey Medical School and colleagues now show that IGF-I and -II cooperate to maintain NSC numbers and the NSCs' ability to self-renew. IGF-I maintains NSC numbers by promoting cell division (via the IGF-I receptor), whereas IGF-II drives the expression of proteins essential for NSC self-renewal and 'stemness' (via the insulin receptor).

The role of IGF-I and -II in maintaining NSC numbers and function might help to explain the cognitive impairments associated with aging, as the abundance of both proteins declines with age.

This study was funded by a Dean's grant from UMDNJ-New Jersey Medical School, NIH grants (R21HL094905, F31NS065607 and T32-HL069752) and a grant from the LeDucq Foundation.