title: The miR-7 identified from collagen biomaterial-based three-dimensional cultured cells regulates neural stem cell differentiation.
abstract: Increasing evidence suggests that three-dimensional (3D) cultures provide more appropriate microenvironments to control stem cell response compared with traditional two-dimensional (2D) cultures. However, the molecular mechanism involved in 3D cultured stem cells is not well known. Several microRNAs whose target genes involved in the regulation of self-renewal and differentiation of stem cells were found to be downregulated in 3D cultured PA-1 cells. Among them, miR-7 was predicted to target Kruppel-like factor 4 (Klf4), a key gene for self-renewal of neural stem cells (NSCs). We showed that the differentiation of NSCs was inhibited in 3D collagen scaffolds compared with 2D cultured cells. The quantitative real-time PCR (qPCR) analysis indicated that the expression of miR-7 and Klf4 changed significantly in 2D cultures, whereas the expression stability of miR-7 and Klf4 was detected in 3D cultures. Using luciferase assay and western blot, Klf4 was identified as a target of miR-7 indicating that miR-7 plays a critical role in maintaining the self-renewal capacity through a Klf4-dependent mechanism in 3D cultured cells. Thus, the collagen scaffold-based 3D cell cultures may provide a platform to reveal the regulatory mechanism of cell regulators, which are difficult to find in traditional 2D cell cultures.
authors.affiliation: 1 State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology , Chinese Academy of Sciences, Beijing, China .
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Xiao
authors.forename: Tong
authors.initials: T
authors.lastname: Chen
authors.forename: Jianshu
authors.initials: J
authors.lastname: Wei
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Lijun
authors.initials: L
authors.lastname: Liu
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.forename: Xiujie
authors.initials: X
authors.lastname: Wang
authors.forename: Xiaoran
authors.initials: X
authors.lastname: Li
authors.forename: Jianwu
authors.initials: J
authors.lastname: Dai
mesh_terms: D020413:3' Untranslated Regions; D001483:Base Sequence; D001665:Binding Sites; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015870:Gene Expression; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000502:physiology*; D058953:Neural Stem Cells / Q000502:physiology*; D034622:RNA Interference; D059467:Transcriptome
chemical_list: D020413:3' Untranslated Regions; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D035683:MicroRNAs; C000715467:KLF4 protein, human; C549242:MIRN7-1 microRNA, human