title: Deep nuclear invaginations are linked to cytoskeletal filaments - integrated bioimaging of epithelial cells in 3D culture.
abstract: The importance of context in regulation of gene expression is now an accepted principle; yet the mechanism by which the microenvironment communicates with the nucleus and chromatin in healthy tissues is poorly understood. A functional role for nuclear and cytoskeletal architecture is suggested by the phenotypic differences observed between epithelial and mesenchymal cells. Capitalizing on recent advances in cryogenic techniques, volume electron microscopy and super-resolution light microscopy, we studied human mammary epithelial cells in three-dimensional (3D) cultures forming growth-arrested acini. Intriguingly, we found deep nuclear invaginations and tunnels traversing the nucleus, encasing cytoskeletal actin and/or intermediate filaments, which connect to the outer nuclear envelope. The cytoskeleton is also connected both to other cells through desmosome adhesion complexes and to the extracellular matrix through hemidesmosomes. This finding supports a physical and/or mechanical link from the desmosomes and hemidesmosomes to the nucleus, which had previously been hypothesized but now is visualized for the first time. These unique structures, including the nuclear invaginations and the cytoskeletal connectivity to the cell nucleus, are consistent with a dynamic reciprocity between the nucleus and the outside of epithelial cells and tissues.
authors: Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA 94720, USA.|Department of Biomedical Engineering, Oregon Health and Science University, 3181 Sam Jackson Park Road, Portland, OR 97239, USA.
authors: Danielle M
authors: 0000-0002-7143-0118
authors: DM
authors: Jorgens
authors: Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors: Jamie L
authors: JL
authors: Inman
authors: Department of Chemistry, University of California, Berkeley, CA 94720, USA.
authors: Michal
authors: M
authors: Wojcik
authors: Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors: Claire
authors: C
authors: Robertson
authors: Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA 94720, USA.
authors: Hildur
authors: 0000-0002-2664-9305
authors: H
authors: Palsdottir
authors: Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA 94720, USA.
authors: Wen-Ting
authors: WT
authors: Tsai
authors: Department of Chemistry, University of California, Berkeley, CA 94720, USA.
authors: Haina
authors: H
authors: Huang
authors: Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.|Department of Biochemistry Instituto de Quimica, Universidade de Sao Paulo, Sao Paulo, 05508-000, Brazil.
authors: Alexandre
authors: A
authors: Bruni-Cardoso
authors: Department of Biomedical Engineering, Oregon Health and Science University, 3181 Sam Jackson Park Road, Portland, OR 97239, USA.
authors: Claudia S
authors: CS
authors: López
authors: Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA MJBissell@lbl.gov MAuer@lbl.gov.
authors: Mina J
authors: MJ
authors: Bissell
authors: Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA 94720, USA.|Department of Chemistry, University of California, Berkeley, CA 94720, USA.
authors: Ke
authors: K
authors: Xu
authors: Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA 94720, USA MJBissell@lbl.gov MAuer@lbl.gov.
authors: Manfred
authors: 0000-0002-5435-9436
authors: M
authors: Auer
mesh_terms: D000199:Actins / Q000378:metabolism; D032701:Biomimetics; D001940:Breast / Q000166:cytology; D002448:Cell Adhesion; D002450:Cell Communication; D018929:Cell Culture Techniques / Q000379:methods*; D059447:Cell Cycle Checkpoints; D022003:Cell Nucleus Structures / Q000378:metabolism* / Q000648:ultrastructure; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D003896:Desmosomes / Q000378:metabolism / Q000648:ultrastructure; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007633:Keratins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009685:Nuclear Envelope / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000199:Actins; D007633:Keratins
keywords: Cytoskeleton; Extracellular matrix; Human mammary epithelial cells; Integrated bioimaging; Mechanotransduction; Nucleoplasmic reticulum