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Abstract Cytoskeleton‐mediated force transmission regulates nucleus morphology. How nuclei shaping occurs in fibrous in vivo environments remains poorly understood. Here suspended nanofiber networks of precisely tunable (nm–µm) diameters are used to quantify nucleus plasticity in fibrous environments mimicking the natural extracellular matrix. Contrary to the apical cap over the nucleus in cells on 2‐dimensional surfaces, the cytoskeleton of cells on fibers displays a uniform actin network caging the nucleus. The role of contractility‐driven caging in sculpting nuclear shapes is investigated as cells spread on aligned single fibers, doublets, and multiple fibers of varying diameters. Cell contractility increases with fiber diameter due to increased focal adhesion clustering and density of actin stress fibers, which correlates with increased mechanosensitive transcription factor Yes‐associated protein (YAP) translocation to the nucleus. Unexpectedly, large‐ and small‐diameter fiber combinations lead to teardrop‐shaped nuclei due to stress fiber anisotropy across the cell. As cells spread on fibers, diameter‐dependent nuclear envelope invaginations that run the nucleus's length are formed at fiber contact sites. The sharpest invaginations enriched with heterochromatin clustering and sites of DNA repair are insufficient to trigger nucleus rupture. Overall, the authors quantitate the previously unknown sculpting and adaptability of nuclei to fibrous environments with pathophysiological implications.
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Piggybacking functionalized DNA nanostructures into live-cell nuclei
DNA origami nanostructures (DOs) are promising tools for applications including drug delivery, biosensing, detecting biomolecules, and probing chromatin substructures. Targeting these nanodevices to mammalian cell nuclei could provide impactful approaches for probing, visualizing, and controlling biomolecular processes within live cells. We present an approach to deliver DOs into live-cell nuclei. We show that these DOs do not undergo detectable structural degradation in cell culture media or cell extracts for 24 hours. To deliver DOs into the nuclei of human U2OS cells, we conjugated 30-nanometer DO nanorods with an antibody raised against a nuclear factor, specifically the largest subunit of RNA polymerase II (Pol II). We find that DOs remain structurally intact in cells for 24 hours, including inside the nucleus. We demonstrate that electroporated anti–Pol II antibody–conjugated DOs are piggybacked into nuclei and exhibit subdiffusive motion inside the nucleus. Our results establish interfacing DOs with a nuclear factor as an effective method to deliver nanodevices into live-cell nuclei.
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- Award ID(s):
- 1933344
- PAR ID:
- 10570649
- Publisher / Repository:
- Science Advances
- Date Published:
- Journal Name:
- Science Advances
- Volume:
- 10
- Issue:
- 27
- ISSN:
- 2375-2548
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/sciadv.adn9423
