title: Microfabrication-based modulation of embryonic stem cell differentiation.
abstract: Embryonic stem (ES) cells form spontaneous aggregates during differentiation, and cell-cell communication in the aggregates plays an important role in differentiation. The development of a controlled differentiation scheme for ES cells has been hindered by the lack of a reliable method to produce uniform aggregate sizes. Conventional techniques, such as hanging drop and suspension cultures, do not allow precise control over size of ES cell aggregates. To surmount this problem, we microfabricated adhesive stencils to make mouse ES (mES) cell aggregates of specific sizes ranging from 100 microm to 500 microm in diameter. With this technique, we studied the effect of the initial aggregate size on ES cell differentiation. After 20 days of induction of differentiation, we analyzed the stem cell populations using gene and protein expression assays as well as biochemical functions. Notably, we found that germ layer differentiation depends on the initial size of the ES cell aggregate. Among the ES cell aggregate sizes tested, the aggregates with 300 microm diameter showed similar differentiation profiles of three germ layers as embryoid bodies made using the "hanging drop" technique. The smaller (100 microm) aggregates showed the increased expression of ectodermal markers compared to the larger (500 microm) aggregates, while the 500 microm aggregates showed the increased expression of mesodermal and endodermal markers compared to the 100 microm aggregates. These results indicate that the initial size of the aggregate is an important factor for ES cell differentiation, and can affect germ layer selection as well as the extent of differentiation.
authors.affiliation: Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Shriners Hospitals for Children and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Jaesung
authors.initials: J
authors.lastname: Park
authors.forename: Cheul H
authors.initials: CH
authors.lastname: Cho
authors.forename: Natesh
authors.initials: N
authors.lastname: Parashurama
authors.forename: Yawen
authors.initials: Y
authors.lastname: Li
authors.forename: François
authors.initials: F
authors.lastname: Berthiaume
authors.forename: Mehmet
authors.initials: M
authors.lastname: Toner
authors.forename: Arno W
authors.initials: AW
authors.lastname: Tilles
authors.forename: Martin L
authors.initials: ML
authors.lastname: Yarmush
mesh_terms: D000818:Animals; D002449:Cell Aggregation / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation / Q000502:physiology*; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D005855:Germ Layers / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008904:Miniaturization; D016133:Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D014157:Transcription Factors