Micropatterning of Single Endothelial Cell Shape Reveals a Tight Coupling between Nuclear Volume in G1 and Proliferation

Roca‐Cusachs, Pere; Alcaraz, Jordi; Sunyer, Raimon; Samitier, J.; Farré, Ramón; Navajas, Daniel

doi:10.1529/biophysj.107.116863

Cited by 177 publications

(202 citation statements)

References 70 publications

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“…To control cell shape and, therefore, be able to quantify nuclear shape as a function of cell shape, we developed adhesive FN-coated micropatterned stripes of width ranging between 10 and 50 m, which alternated with stripes covered with nonadhesive polyethylene glycol (PEG) (Fig. 1C) (3)(4)(5)(6). Mouse embryonic fibroblasts were allowed to spread, and within 30 min, the majority of the cells had moved to, and aligned in, the direction of the FN stripes (Fig.…”

Section: Resultsmentioning

confidence: 99%

A perinuclear actin cap regulates nuclear shape

Khatau¹,

Hale²,

Stewart-Hutchinson

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

532

602

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Defects in nuclear morphology often correlate with the onset of disease, including cancer, progeria, cardiomyopathy, and muscular dystrophy. However, the mechanism by which a cell controls its nuclear shape is unknown. Here, we use adhesive micropatterned surfaces to control the overall shape of fibroblasts and find that the shape of the nucleus is tightly regulated by the underlying cell adhesion geometry. We found that this regulation occurs through a dome-like actin cap that covers the top of the nucleus. This cap is composed of contractile actin filament bundles containing phosphorylated myosin, which form a highly organized, dynamic, and oriented structure in a wide variety of cells. The perinuclear actin cap is specifically disorganized or eliminated by inhibition of actomyosin contractility and rupture of the LINC complexes, which connect the nucleus to the actin cap. The organization of this actin cap and its nuclear shape-determining function are disrupted in cells from mouse models of accelerated aging (progeria) and muscular dystrophy with distorted nuclei caused by alterations of A-type lamins. These results highlight the interplay between cell shape, nuclear shape, and cell adhesion mediated by the perinuclear actin cap.LINC complexes ͉ nucleus I n 1921, Champy and Carleton suggested an apparent correlation between the shape of various types of animal cells and the shape of their respective nuclei (1). Moreover, defects in nuclear shape are routinely used in the lab and in clinical settings as markers of disease and differentiation in human cells and tissues (2). However, remarkably little is known about the factors that determine nuclear morphology in living cells. In particular, the molecular mechanisms that govern the shape of the interphase nucleus are unknown. Here we show that an actin filament structure that forms a cap or dome located above the apical surface of the nucleus tightly controls nuclear shape and identify key associated cytoskeletal regulators of its organization and nuclear shape-determining function. The organization and function of the perinuclear actin cap are deregulated in diseased cells with distorted nuclei. Results and DiscussionTo test the hypothesis of a correlation between the shape of the nucleus and the overall cell shape, mouse embryonic fibroblasts were dispersed on fibronectin (FN)-coated glass substrates. Using morphometric analysis, we found that nuclear shape and cellular shape correlated ( Fig. 1 A and B). Shape factor, defined as 4 A/P 2 (where A and P are the nuclear area and perimeter), approaches 1 for a rounded nucleus and approaches 0 for an elongated nucleus. Elongated cells typically showed an elongated nucleus of low shape factor; rounded cells showed a rounded nucleus of high shape factor (Fig. 1 A). To control cell shape and, therefore, be able to quantify nuclear shape as a function of cell shape, we developed adhesive FN-coated micropatterned stripes of width ranging between 10 and 50 m, which alternated with stripes covered with nonadhesive poly...

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Section: Resultsmentioning

confidence: 99%

A perinuclear actin cap regulates nuclear shape

Khatau¹,

Hale²,

Stewart-Hutchinson

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

532

602

View full text Add to dashboard Cite

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“…The assembly of actin filaments into contractile stress fibers follows a mechanism common among adherent cell types (49), and actin stress fiber alignment is also seen in other cell types patterned into rectangular shapes (26,50,51). Nonmuscle actin stress fibers have several homologies with their myofibril isoforms in contractility, organization, and composition (49,52,53).…”

Section: Discussionmentioning

confidence: 99%

Contractility of single cardiomyocytes differentiated from pluripotent stem cells depends on physiological shape and substrate stiffness

Ribeiro

Ang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

405

456

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Single cardiomyocytes contain myofibrils that harbor the sarcomerebased contractile machinery of the myocardium. Cardiomyocytes differentiated from human pluripotent stem cells (hPSC-CMs) have potential as an in vitro model of heart activity. However, their fetallike misalignment of myofibrils limits their usefulness for modeling contractile activity. We analyzed the effects of cell shape and substrate stiffness on the shortening and movement of labeled sarcomeres and the translation of sarcomere activity to mechanical output (contractility) in live engineered hPSC-CMs. Single hPSC-CMs were cultured on polyacrylamide substrates of physiological stiffness (10 kPa), and Matrigel micropatterns were used to generate physiological shapes (2,000-μm 2 rectangles with length:width aspect ratios of 5:1-7:1) and a mature alignment of myofibrils. Translation of sarcomere shortening to mechanical output was highest in 7:1 hPSC-CMs. Increased substrate stiffness and applied overstretch induced myofibril defects in 7:1 hPSC-CMs and decreased mechanical output. Inhibitors of nonmuscle myosin activity repressed the assembly of myofibrils, showing that subcellular tension drives the improved contractile activity in these engineered hPSC-CMs. Other factors associated with improved contractility were axially directed calcium flow, systematic mitochondrial distribution, more mature electrophysiology, and evidence of transverse-tubule formation. These findings support the potential of these engineered hPSC-CMs as powerful models for studying myocardial contractility at the cellular level.contractility | sarcomeres | cardiomyocyte | stem cell | single cell

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“…For instance, it is well known that the formation of new blood capillaries requires the polarization and directed migration of endothelial cells (ECs) through large cell elongations [5][6][7][8][9] . In addition, cell shape changes in ECs are commonly associated with nuclear shape remodelling [10][11][12][13] , which is emerging as a potential regulator of genome function [14][15][16] . To explain the link between cellular morphology and information control within living cells, Maniotis et al 17 proposed that cell shape informations are transduced into gene expression through mechanical forces transmitted by the cytoskeleton.…”

mentioning

confidence: 99%

Spatial coordination between cell and nuclear shape within micropatterned endothelial cells

2012

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Growing evidence suggests that cytoplasmic actin filaments are essential factors in the modulation of nuclear shape and function. However, the mechanistic understanding of the internal orchestration between cell and nuclear shape is still lacking. Here we show that orientation and deformation of the nucleus are regulated by lateral compressive forces driven by tension in central actomyosin fibres. By using a combination of micro-manipulation tools, our study reveals that tension in central stress fibres is gradually generated by anisotropic force contraction dipoles, which expand as the cell elongates and spreads. our findings indicate that large-scale cell shape changes induce a drastic condensation of chromatin and dramatically affect cell proliferation. on the basis of these findings, we propose a simple mechanical model that quantitatively accounts for our experimental data and provides a conceptual framework for the mechanistic coordination between cell and nuclear shape.

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Micropatterning of Single Endothelial Cell Shape Reveals a Tight Coupling between Nuclear Volume in G1 and Proliferation

Cited by 177 publications

References 70 publications

A perinuclear actin cap regulates nuclear shape

A perinuclear actin cap regulates nuclear shape

Contractility of single cardiomyocytes differentiated from pluripotent stem cells depends on physiological shape and substrate stiffness

Spatial coordination between cell and nuclear shape within micropatterned endothelial cells

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