Lin He

Associate Professor of Cell and Developmental Biology
Department of Molecular and Cell Biology
University of California, Berkeley

Pluripotent stem cells, either isolated from inner-cell mass of mammalian blastocysts (ES cells) or generated by enforced expression of key transcription factors (iPS cells), possess the capacity for self-renewal and the plasticity for differentiation. The He lab aims to investigate the roles of non-coding RNAs (ncRNAs) in the key signaling pathways regulating stem cell self-renewal and differentiation, with particular efforts initially focused on microRNAs. Key evidence suggesting miRNAs’ involvement in stem cell biology comes from the observation that LIN28, a negative regulator for the biogenesis of specific miRNAs, can promote pluripotency in somatic cells when over-expressed along with Nanog, Sox2 and Oct4. Consistently, if global miRNA biogenesis is deficient due to the defect in Dicer or DGCR8, the differentiation capacity of the ES cells is greatly compromised. These findings have raised an intriguing hypothesis that miRNAs, and possibly other ncRNAs, are key regulators for stem cell pluripotency. Using ES cell culture studies and mouse genetic studies, the He group investigates the roles of miRNA in maintaining pluripotency and promoting differentiation.