It is one of the core tasks to learn human brain and uncover the cognition and intelligence. In the adult brain, neural stem cells are restricted in two regions of the subgranular zone of the hippocampal dentate gyrus and suventricular zone of lateral ventricles. These adult neural stem cells can self-renew and differentiate into neurons, which finally integrate into the existing circuitry. It is important to learn how the molecules and mechanisms control neural stem cell proliferation and neurogenesis. However, it is unclear which epigenetic molecules are involved in the neural stem cell maintenance and proliferation. 

In this study, Dr. Jiao’s group found that one epigenetic member H3K27 methytransferase Ezh2 regulates neural stem cell renewal, the transition from neural stem cells to neural progenitor cells and neurogenesis. The deletion of Ezh2 in NSCs/progenitor cells results in a reduction in progenitor cell proliferation. Furthermore, they found that Ezh2 regulates progenitor cell proliferation by suppressing Pten expression and promoting the activation of Akt-mTOR. Strikingly, conditional knockout of Ezh2 ultimately results in impairments in spatial learning and memory, contextual fear memory, and pattern separation. The study will increase our knowledge how epigenetic molecules affect neural stem cell self renewal and neurogenesis and provides theoretical evidence to understand the brain memory. 

This study was mainly carried out by graduate student Juan Zhang, Assistant investigator Dr. Fen Ji, and colleagues under the supervision of Dr. Jianwei Jiao in the Institute of Zoology, Chinese Academy of Sciences, in collaboration with the laboratories of Dr. Zengqiang Yuang and Dr. Guangju Ji from Institute of Biophysics, Chinese Academy of Sciences. This work entitled “Ezh2 Regulates Adult Hippocampal Neurogenesis and Memory” was published in the “the Journal of Neuroscience” on April 9, 2014. This study was supported by grants from National Key Basic Research Program of China, the National Science Foundation of China, and the Strategic Priority Research Program.