title: Human pluripotent stem cell culture density modulates YAP signaling.
abstract: Human pluripotent stem cell (hPSC) density is an important factor in self-renewal and differentiation fates; however, the mechanisms through which hPSCs sense cell density and process this information in making cell fate decisions remain to be fully understood. One particular pathway that may prove important in density-dependent signaling in hPSCs is the Hippo pathway, which is regulated by cell-cell contact and mechanosensing through the cytoskeleton and has been linked to the maintenance of stem cell pluripotency. To probe regulation of Hippo pathway activity in hPSCs, we assessed whether Hippo pathway transcriptional activator YAP was differentially modulated by cell density. At higher cell densities, YAP phosphorylation and localization to the cytoplasm increased, which led to decreased YAP-mediated transcriptional activity. Furthermore, total YAP protein levels diminished at high cell density due to the phosphorylation-targeted degradation of YAP. Inducible shRNA knockdown of YAP reduced expression of YAP target genes and pluripotency genes. Finally, the density-dependent increase of neuroepithelial cell differentiation was mitigated by shRNA knockdown of YAP. Our results suggest a pivotal role of YAP in cell density-mediated fate decisions in hPSCs.
authors.affiliation: Department of Chemical & Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors.forename: Cheston
authors.initials: C
authors.lastname: Hsiao
authors.affiliation: Department of Chemical & Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lampe
authors.affiliation: Department of Chemical & Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors.forename: Songkhun
authors.initials: S
authors.lastname: Nillasithanukroh
authors.affiliation: Department of Chemical & Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Han
authors.affiliation: Department of Chemical & Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Lian
authors.affiliation: Department of Chemical & Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA. sppalecek@wisc.edu.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Palecek
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism*; D002450:Cell Communication; D002452:Cell Count; D002454:Cell Differentiation; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation; D003593:Cytoplasm / Q000378:metabolism*; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D039904:Pluripotent Stem Cells / Q000166:cytology*; D015398:Signal Transduction; D014157:Transcription Factors; D014158:Transcription, Genetic; D000091102:YAP-Signaling Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D010750:Phosphoproteins; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human
keywords: Cell density; Human pluripotent stem cells; Neural differentiation; Self-renewal; YAP