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Lemma B, Nelson CM. Spatial patterning of energy metabolism during tissue morphogenesis. Curr Opin Cell Biol 2023; 85:102235. [PMID: 37696131 PMCID: PMC10840784 DOI: 10.1016/j.ceb.2023.102235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 08/12/2023] [Accepted: 08/13/2023] [Indexed: 09/13/2023]
Abstract
Biophysical signaling organizes forces to drive tissue morphogenesis, a process co-opted during disease progression. The systematic buildup of forces at the tissue scale is energetically demanding. Just as mechanical forces, gene expression, and concentrations of morphogens vary spatially across a developing tissue, there might similarly be spatial variations in energy consumption. Recent studies have started to uncover the connections between spatial patterns of mechanical forces and spatial patterns of energy metabolism. Here, we define and review the concept of energy metabolism during tissue morphogenesis. We highlight experiments showing spatial variations in energy metabolism across several model systems, categorized by morphogenetic motif, including convergent extension, branching, and migration. Finally, we discuss approaches to further enable quantitative measurements of energy production and consumption during morphogenesis.
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Affiliation(s)
- Bezia Lemma
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Celeste M Nelson
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Foster PJ, Bae J, Lemma B, Zheng J, Ireland W, Chandrakar P, Boros R, Dogic Z, Needleman DJ, Vlassak JJ. Dissipation and energy propagation across scales in an active cytoskeletal material. Proc Natl Acad Sci U S A 2023; 120:e2207662120. [PMID: 37000847 PMCID: PMC10083585 DOI: 10.1073/pnas.2207662120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 02/22/2023] [Indexed: 04/03/2023] Open
Abstract
Living systems are intrinsically nonequilibrium: They use metabolically derived chemical energy to power their emergent dynamics and self-organization. A crucial driver of these dynamics is the cellular cytoskeleton, a defining example of an active material where the energy injected by molecular motors cascades across length scales, allowing the material to break the constraints of thermodynamic equilibrium and display emergent nonequilibrium dynamics only possible due to the constant influx of energy. Notwithstanding recent experimental advances in the use of local probes to quantify entropy production and the breaking of detailed balance, little is known about the energetics of active materials or how energy propagates from the molecular to emergent length scales. Here, we use a recently developed picowatt calorimeter to experimentally measure the energetics of an active microtubule gel that displays emergent large-scale flows. We find that only approximately one-billionth of the system's total energy consumption contributes to these emergent flows. We develop a chemical kinetics model that quantitatively captures how the system's total thermal dissipation varies with ATP and microtubule concentrations but that breaks down at high motor concentration, signaling an interference between motors. Finally, we estimate how energy losses accumulate across scales. Taken together, these results highlight energetic efficiency as a key consideration for the engineering of active materials and are a powerful step toward developing a nonequilibrium thermodynamics of living systems.
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Affiliation(s)
- Peter J. Foster
- Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Department of Physics, Brandeis University, Waltham, MA02454
| | - Jinhye Bae
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
- Department of NanoEngineering, University of California San Diego, La Jolla, CA92093
| | - Bezia Lemma
- Department of Physics, Brandeis University, Waltham, MA02454
- Department of Physics, Harvard University, Cambridge, MA02138
- Department of Physics, University of California, Santa Barbara, CA93106
| | - Juanjuan Zheng
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - William Ireland
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Pooja Chandrakar
- Department of Physics, Brandeis University, Waltham, MA02454
- Department of Physics, University of California, Santa Barbara, CA93106
| | - Rémi Boros
- Department of Physics, University of California, Santa Barbara, CA93106
| | - Zvonimir Dogic
- Department of Physics, Brandeis University, Waltham, MA02454
- Department of Physics, University of California, Santa Barbara, CA93106
| | - Daniel J. Needleman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA02138
- Center for Computational Biology, Flatiron Institute, New York, NY10010
| | - Joost J. Vlassak
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
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Goodwin K, Lemma B, Zhang P, Boukind A, Nelson CM. Plasticity in airway smooth muscle differentiation during mouse lung development. Dev Cell 2023; 58:338-347.e4. [PMID: 36868232 PMCID: PMC10149112 DOI: 10.1016/j.devcel.2023.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 11/27/2022] [Accepted: 02/06/2023] [Indexed: 03/05/2023]
Abstract
It has been proposed that smooth muscle differentiation may physically sculpt airway epithelial branches in mammalian lungs. Serum response factor (SRF) acts with its co-factor myocardin to activate the expression of contractile smooth muscle markers. In the adult, however, smooth muscle exhibits a variety of phenotypes beyond contractile, and these are independent of SRF/myocardin-induced transcription. To determine whether a similar phenotypic plasticity is exhibited during development, we deleted Srf from the mouse embryonic pulmonary mesenchyme. Srf-mutant lungs branch normally, and the mesenchyme displays mechanical properties indistinguishable from controls. scRNA-seq identified an Srf-null smooth muscle cluster, wrapping the airways of mutant lungs, which lacks contractile smooth muscle markers but retains many features of control smooth muscle. Srf-null embryonic airway smooth muscle exhibits a synthetic phenotype, compared with the contractile phenotype of mature wild-type airway smooth muscle. Our findings identify plasticity in embryonic airway smooth muscle and demonstrate that a synthetic smooth muscle layer promotes airway branching morphogenesis.
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Affiliation(s)
- Katharine Goodwin
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Bezia Lemma
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Pengfei Zhang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Adam Boukind
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Celeste M Nelson
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Lemma B, Mitchell NP, Subramanian R, Needleman DJ, Dogic Z. Active Microphase Separation in Mixtures of Microtubules and Tip-Accumulating Molecular Motors. Phys Rev X 2022; 12:031006. [PMID: 36643940 PMCID: PMC9835929 DOI: 10.1103/physrevx.12.031006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Mixtures of filaments and molecular motors form active materials with diverse dynamical behaviors that vary based on their constituents' molecular properties. To develop a multiscale of these materials, we map the nonequilibrium phase diagram of microtubules and tip-accumulating kinesin-4 molecular motors. We find that kinesin-4 can drive either global contractions or turbulentlike extensile dynamics, depending on the concentrations of both microtubules and a bundling agent. We also observe a range of spatially heterogeneous nonequilibrium phases, including finite-sized radial asters, 1D wormlike chains, extended 2D bilayers, and system-spanning 3D active foams. Finally, we describe intricate kinetic pathways that yield microphase separated structures and arise from the inherent frustration between the orientational order of filamentous microtubules and the positional order of tip-accumulating molecular motors. Our work reveals a range of novel active states. It also shows that the form of active stresses is not solely dictated by the properties of individual motors and filaments, but is also contingent on the constituent concentrations and spatial arrangement of motors on the filaments.
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Affiliation(s)
- Bezia Lemma
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
- Physics Department, Brandeis University, Waltham, Massachusetts 02453, USA
- Physics Department, University of California, Santa Barbara, California 93106, USA
| | - Noah P. Mitchell
- Physics Department, University of California, Santa Barbara, California 93106, USA
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA
| | - Radhika Subramanian
- Molecular Biology Department, Massachusetts General Hospital Boston, Massachusetts 02114, USA
- Genetics Department, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Daniel J. Needleman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Molecular and Cellular Biology Department, Harvard University, Cambridge, Massachusetts 02138, USA
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA
| | - Zvonimir Dogic
- Physics Department, Brandeis University, Waltham, Massachusetts 02453, USA
- Physics Department, University of California, Santa Barbara, California 93106, USA
- Biomolecular Science and Engineering Department, University of California, Santa Barbara, California 93106, USA
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Chandrakar P, Berezney J, Lemma B, Hishamunda B, Berry A, Wu KT, Subramanian R, Chung J, Needleman D, Gelles J, Dogic Z. Engineering stability, longevity, and miscibility of microtubule-based active fluids. Soft Matter 2022; 18:1825-1835. [PMID: 35167642 DOI: 10.1039/d1sm01289d] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Microtubule-based active matter provides insight into the self-organization of motile interacting constituents. We describe several formulations of microtubule-based 3D active isotropic fluids. Dynamics of these fluids is powered by three types of kinesin motors: a processive motor, a non-processive motor, and a motor which is permanently linked to a microtubule backbone. Another modification uses a specific microtubule crosslinker to induce bundle formation instead of a non-specific polymer depletant. In comparison to the already established system, each formulation exhibits distinct properties. These developments reveal the temporal stability of microtubule-based active fluids while extending their reach and the applicability.
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Affiliation(s)
- Pooja Chandrakar
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
- Department of Physics, University of California, Santa Barbara, California 93106, USA.
| | - John Berezney
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Bezia Lemma
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
- Department of Physics, University of California, Santa Barbara, California 93106, USA.
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Bernard Hishamunda
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Angela Berry
- Hampton University School of Pharmacy, 121 William R. Harvey Way, Hampton, VA 23668, USA
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Kun-Ta Wu
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
- Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
| | - Radhika Subramanian
- Department of Genetics, HMS and Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Johnson Chung
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Daniel Needleman
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Zvonimir Dogic
- The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
- Department of Physics, University of California, Santa Barbara, California 93106, USA.
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Fürthauer S, Lemma B, Foster PJ, Ems-McClung SC, Yu CH, Walczak CE, Dogic Z, Needleman DJ, Shelley MJ. Self-straining of actively crosslinked microtubule networks. Nat Phys 2019; 15:1295-1300. [PMID: 32322291 PMCID: PMC7176317 DOI: 10.1038/s41567-019-0642-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 07/17/2019] [Indexed: 05/26/2023]
Abstract
Cytoskeletal networks are foundational examples of active matter and central to self-organized structures in the cell. In vivo, these networks are active and densely crosslinked. Relating their large-scale dynamics to the properties of their constituents remains an unsolved problem. Here, we study an in vitro active gel made from aligned microtubules and XCTK2 kinesin motors. Using photobleaching, we demonstrate that the gel's aligned microtubules, driven by motors, continually slide past each other at a speed independent of the local microtubule polarity and motor concentration. This phenomenon is also observed, and remains unexplained, in spindles. We derive a general framework for coarse graining microtubule gels crosslinked by molecular motors from microscopic considerations. Using microtubule-microtubule coupling through a force-velocity relationship for kinesin, this theory naturally explains the experimental results: motors generate an active strain rate in regions of changing polarity, which allows microtubules of opposite polarities to slide past each other without stressing the material.
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Affiliation(s)
| | - Bezia Lemma
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Physics, Brandeis University, Waltham, MA, USA
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Peter J Foster
- Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Che-Hang Yu
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, USA
| | | | - Zvonimir Dogic
- Department of Physics, Brandeis University, Waltham, MA, USA
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Daniel J Needleman
- Paulson School of Engineering & Applied Science and Department of Molecular & Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Michael J Shelley
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
- Courant Institute, New York University, New York, NY, USA
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Ashine S, Lemma B. Malignant tumours at Yirga Alem Hospital. Ethiop Med J 1999; 37:163-72. [PMID: 11957313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
A ten year (January 1986 to December 1995) retrospective analysis of biopsy results of patients seen at Yirga Alem Hospital was conducted. There were 841 histologically certified cancers (410 males and 431 females). The mean and the median ages were 42.1 and 42 years, respectively. Skin and lymphoreticular cancers were the commonest in males while cervical cancer was by far the commonest in females followed by skin, breast and ovarian cancers. In the paediatric age group, soft tissue sarcoma occurred most often followed by retinoblastoma and lymphoma. The results of the study were similar to that of previous studies done in Ethiopia. The biases that might have influenced the results of the study are discussed. A hospital cancer registry is recommended to generate more reliable data.
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Affiliation(s)
- S Ashine
- Yirga Alem Hospital, P.O. Box 70, Yirga Alem, Ethiopia
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Abstract
The incidence of fascioliasis was studied in Asela, Awasa, Debre Zeit and Debre Berhan by using 153 experimental sheep divided up into 4 groups designated tracer sheep, Controls I, II and III. Fasciola hepatica was encountered in Debre Berhan, Asela and Awasa, but it was not detected at Debre Zeit. In all areas, it was most frequently recovered after heavy rains. Altitude, soil type, salt content and local crowding of animals in watering sites appear to have influenced the varying degrees of incidence and intensity of infection.
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