In an aging society with dementia imposing an increasing threat to higher brain cognitive functions, understanding the molecular and cellular events of adult neurogenesis is imperative. Interleukin-6 (IL-6), along with its agonistic acting soluble receptor sIL-6R (the combined proteins are also known as Hyper-IL-6), is a promising cytokine that can support neurogenesis under conditions of neurodegeneration when neuron replacement is needed. In contrast to the previously reported gliogenic effects of activation of the IL-6–signal transducer and activator of transcription 3 (STAT3) axis, this review summarizes recent studies showing that IL-6 activation can be neurogenic and has potential therapeutic applications for the treatment of neurodegenerative diseases such as Parkinson’s disease.
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