title: Morphological differences of primary cilia between human induced pluripotent stem cells and their parental somatic cells.
abstract: Human induced pluripotent stem cell (hiPSC) reprogramming possesses enormous potential in stem cell research and disease modeling. Chemical and mechanical signaling has been implicated in the maintenance of pluripotency of hiPSCs, as well as their differentiation pathways toward various lineages. Primary cilia have been shown to play a critical role in mechanochemical signaling across a wide spectrum of cell types. The functions of primary cilia in hiPSCs and their characteristic changes during the reprogramming process remain largely vague. This work focused on understanding how reprogramming affects the mechanical characteristics of primary cilia. Using immunofluorescence imaging assays, we validated the presence of primary cilia on reprogrammed cells. These reprogrammed cells had high expression levels of pluripotency markers, Nanog and Cripto, shown by quantitative polymerase chain reaction assays. We also found high expression of hedgehog signaling proteins Patched1 (Ptch1), Smoothened (Smo), Gli1, and Gli2 in reprogrammed cells. Stimulation of the hedgehog pathway resulted in the concerted movement of Ptch1 out of the cilia and Smo into the cilia, implying that the cilia on iPSCs contain functioning hedgehog machinery. The mean length of primary cilia in reprogrammed cells was shorter than those of parental human fibroblasts. Morphometric analyses revealed that reprogramming resulted in an increase in the curvature of primary cilia from ∼0.015 to 0.064 μm(-1), indicating an underlying approximately fourfold decrease in their rigidity, and a decrease in length of primary cilia from ∼2.38 to ∼1.45 μm. Furthermore, reprogramming resulted in fewer primary cilia displaying kinked geometries.
authors.affiliation: 1 Department of Mechanical Engineering, Columbia University , New York, New York.
authors.forename: Bhavik B
authors.initials: BB
authors.lastname: Nathwani
authors.forename: Christine H
authors.initials: CH
authors.lastname: Miller
authors.forename: Tung-Lin Tony
authors.initials: TL
authors.lastname: Yang
authors.forename: Jamie Lee
authors.initials: JL
authors.lastname: Solimano
authors.forename: Jung-Chi
authors.initials: JC
authors.lastname: Liao
mesh_terms: D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D065150:Cellular Reprogramming / Q000235:genetics*; D002923:Cilia / Q000502:physiology*; D058851:GPI-Linked Proteins / Q000096:biosynthesis; D018398:Homeodomain Proteins / Q000096:biosynthesis; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis; D051741:Kruppel-Like Transcription Factors / Q000096:biosynthesis; D000071317:Nanog Homeobox Protein; D009363:Neoplasm Proteins / Q000096:biosynthesis; D009687:Nuclear Proteins / Q000096:biosynthesis; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D011956:Receptors, Cell Surface / Q000096:biosynthesis; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis; D015398:Signal Transduction / Q000235:genetics; D000072086:Smoothened Receptor; D014157:Transcription Factors / Q000096:biosynthesis; D000071676:Zinc Finger Protein GLI1; D000075746:Zinc Finger Protein Gli2
chemical_list: C400551:GLI1 protein, human; C082593:GLI2 protein, human; D058851:GPI-Linked Proteins; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D051741:Kruppel-Like Transcription Factors; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C000606236:PTCH1 protein, human; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C491023:SMO protein, human; D000072086:Smoothened Receptor; C070636:TDGF1 protein, human; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1; D000075746:Zinc Finger Protein Gli2