1
|
Neininger-Castro AC, Hayes JB, Sanchez ZC, Taneja N, Fenix AM, Moparthi S, Vassilopoulos S, Burnette DT. Independent regulation of Z-lines and M-lines during sarcomere assembly in cardiac myocytes revealed by the automatic image analysis software sarcApp. bioRxiv 2023:2023.01.11.523681. [PMID: 36711995 PMCID: PMC9882215 DOI: 10.1101/2023.01.11.523681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Sarcomeres are the basic contractile units within cardiac myocytes, and the collective shortening of sarcomeres aligned along myofibrils generates the force driving the heartbeat. The alignment of the individual sarcomeres is important for proper force generation, and misaligned sarcomeres are associated with diseases including cardiomyopathies and COVID-19. The actin bundling protein, α-actinin-2, localizes to the "Z-Bodies" of sarcomere precursors and the "Z-Lines" of sarcomeres, and has been used previously to assess sarcomere assembly and maintenance. Previous measurements of α-actinin-2 organization have been largely accomplished manually, which is time-consuming and has hampered research progress. Here, we introduce sarcApp, an image analysis tool that quantifies several components of the cardiac sarcomere and their alignment in muscle cells and tissue. We first developed sarcApp to utilize deep learning-based segmentation and real space quantification to measure α-actinin-2 structures and determine the organization of both precursors and sarcomeres/myofibrils. We then expanded sarcApp to analyze "M-Lines" using the localization of myomesin and a protein that connects the Z-Lines to the M-Line (titin). sarcApp produces 33 distinct measurements per cell and 24 per myofibril that allow for precise quantification of changes in sarcomeres, myofibrils, and their precursors. We validated this system with perturbations to sarcomere assembly. We found perturbations that affected Z-Lines and M-Lines differently, suggesting that they may be regulated independently during sarcomere assembly.
Collapse
Affiliation(s)
- Abigail C. Neininger-Castro
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - James B. Hayes
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Zachary C. Sanchez
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Aidan M. Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Satish Moparthi
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Stéphane Vassilopoulos
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| |
Collapse
|
2
|
Chen B, Chang BJ, Roudot P, Zhou F, Sapoznik E, Marlar-Pavey M, Hayes JB, Brown PT, Zeng CW, Lambert T, Friedman JR, Zhang CL, Burnette DT, Shepherd DP, Dean KM, Fiolka RP. Resolution doubling in light-sheet microscopy via oblique plane structured illumination. Nat Methods 2022; 19:1419-1426. [PMID: 36280718 PMCID: PMC10182454 DOI: 10.1038/s41592-022-01635-8] [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: 04/09/2022] [Accepted: 09/01/2022] [Indexed: 11/09/2022]
Abstract
Structured illumination microscopy (SIM) doubles the spatial resolution of a fluorescence microscope without requiring high laser powers or specialized fluorophores. However, the excitation of out-of-focus fluorescence can accelerate photobleaching and phototoxicity. In contrast, light-sheet fluorescence microscopy (LSFM) largely avoids exciting out-of-focus fluorescence, thereby enabling volumetric imaging with low photobleaching and intrinsic optical sectioning. Combining SIM with LSFM would enable gentle three-dimensional (3D) imaging at doubled resolution. However, multiple orientations of the illumination pattern, which are needed for isotropic resolution doubling in SIM, are challenging to implement in a light-sheet format. Here we show that multidirectional structured illumination can be implemented in oblique plane microscopy, an LSFM technique that uses a single objective for excitation and detection, in a straightforward manner. We demonstrate isotropic lateral resolution below 150 nm, combined with lower phototoxicity compared to traditional SIM systems and volumetric acquisition speed exceeding 1 Hz.
Collapse
Affiliation(s)
- Bingying Chen
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bo-Jui Chang
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Philippe Roudot
- Aix-Marseille University, CNRS, Centrale Marseille, I2M, Turing Centre for Living Systems, Marseille, France
| | - Felix Zhou
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Etai Sapoznik
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Genentech, San Francisco, USA
| | - Madeleine Marlar-Pavey
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - James B Hayes
- Department of Cell and Developmental Biology, Vanderbilt Medical Center, University of Vanderbilt, Nashville, TN, USA
| | - Peter T Brown
- Center for Biological Physics and Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Chih-Wei Zeng
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Talley Lambert
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Jonathan R Friedman
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chun-Li Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt Medical Center, University of Vanderbilt, Nashville, TN, USA
| | - Douglas P Shepherd
- Center for Biological Physics and Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Kevin M Dean
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Reto P Fiolka
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| |
Collapse
|
3
|
Ma Z, Lytle NK, Chen B, Jyotsana N, Novak SW, Cho CJ, Caplan L, Ben-Levy O, Neininger AC, Burnette DT, Trinh VQ, Tan MCB, Patterson EA, Arrojo E Drigo R, Giraddi RR, Ramos C, Means AL, Matsumoto I, Manor U, Mills JC, Goldenring JR, Lau KS, Wahl GM, DelGiorno KE. Single-Cell Transcriptomics Reveals a Conserved Metaplasia Program in Pancreatic Injury. Gastroenterology 2022; 162:604-620.e20. [PMID: 34695382 PMCID: PMC8792222 DOI: 10.1053/j.gastro.2021.10.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/15/2021] [Accepted: 10/09/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Acinar to ductal metaplasia (ADM) occurs in the pancreas in response to tissue injury and is a potential precursor for adenocarcinoma. The goal of these studies was to define the populations arising from ADM, the associated transcriptional changes, and markers of disease progression. METHODS Acinar cells were lineage-traced with enhanced yellow fluorescent protein (EYFP) to follow their fate post-injury. Transcripts of more than 13,000 EYFP+ cells were determined using single-cell RNA sequencing (scRNA-seq). Developmental trajectories were generated. Data were compared with gastric metaplasia, KrasG12D-induced neoplasia, and human pancreatitis. Results were confirmed by immunostaining and electron microscopy. KrasG12D was expressed in injury-induced ADM using several inducible Cre drivers. Surgical specimens of chronic pancreatitis from 15 patients were evaluated by immunostaining. RESULTS scRNA-seq of ADM revealed emergence of a mucin/ductal population resembling gastric pyloric metaplasia. Lineage trajectories suggest that some pyloric metaplasia cells can generate tuft and enteroendocrine cells (EECs). Comparison with KrasG12D-induced ADM identifies populations associated with disease progression. Activation of KrasG12D expression in HNF1B+ or POU2F3+ ADM populations leads to neoplastic transformation and formation of MUC5AC+ gastric-pit-like cells. Human pancreatitis samples also harbor pyloric metaplasia with a similar transcriptional phenotype. CONCLUSIONS Under conditions of chronic injury, acinar cells undergo a pyloric-type metaplasia to mucinous progenitor-like populations, which seed disparate tuft cell and EEC lineages. ADM-derived EEC subtypes are diverse. KrasG12D expression is sufficient to drive neoplasia when targeted to injury-induced ADM populations and offers an alternative origin for tumorigenesis. This program is conserved in human pancreatitis, providing insight into early events in pancreas diseases.
Collapse
Affiliation(s)
- Zhibo Ma
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California
| | - Nikki K Lytle
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California
| | - Bob Chen
- Program in Chemical and Physical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Nidhi Jyotsana
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Sammy Weiser Novak
- Waitt Advanced Biophotonics Center, Salk Insitute for Biological Studies, La Jolla, California
| | - Charles J Cho
- Section of Gastroenterology and Hepatology, Baylor College of Medicine, Houston, Texas
| | - Leah Caplan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Olivia Ben-Levy
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Dylan T Burnette
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Ingram Cancer Center, Nashville, Tennessee
| | - Vincent Q Trinh
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Marcus C B Tan
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee; Vanderbilt Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Emilee A Patterson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Rafael Arrojo E Drigo
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Rajshekhar R Giraddi
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California
| | - Cynthia Ramos
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California
| | - Anna L Means
- Vanderbilt Ingram Cancer Center, Nashville, Tennessee; Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee; Vanderbilt Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | | | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Insitute for Biological Studies, La Jolla, California
| | - Jason C Mills
- Section of Gastroenterology and Hepatology, Baylor College of Medicine, Houston, Texas
| | - James R Goldenring
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Ingram Cancer Center, Nashville, Tennessee; Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee; Vanderbilt Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee; Nashville VA Medical Center, Nashville, Tennessee
| | - Ken S Lau
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Ingram Cancer Center, Nashville, Tennessee; Vanderbilt Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Geoffrey M Wahl
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California
| | - Kathleen E DelGiorno
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Ingram Cancer Center, Nashville, Tennessee; Vanderbilt Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee.
| |
Collapse
|
4
|
Zhovmer AS, Manning A, Smith C, Hayes JB, Burnette DT, Wang J, Cartagena-Rivera AX, Dokholyan NV, Singh RK, Tabdanov ED. Mechanical Counterbalance of Kinesin and Dynein Motors in a Microtubular Network Regulates Cell Mechanics, 3D Architecture, and Mechanosensing. ACS Nano 2021; 15:17528-17548. [PMID: 34677937 PMCID: PMC9291236 DOI: 10.1021/acsnano.1c04435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Microtubules (MTs) and MT motor proteins form active 3D networks made of unstretchable cables with rod-like bending mechanics that provide cells with a dynamically changing structural scaffold. In this study, we report an antagonistic mechanical balance within the dynein-kinesin microtubular motor system. Dynein activity drives the microtubular network inward compaction, while isolated activity of kinesins bundles and expands MTs into giant circular bands that deform the cell cortex into discoids. Furthermore, we show that dyneins recruit MTs to sites of cell adhesion, increasing the topographic contact guidance of cells, while kinesins antagonize it via retraction of MTs from sites of cell adhesion. Actin-to-microtubule translocation of septin-9 enhances kinesin-MT interactions, outbalances the activity of kinesins over that of dyneins, and induces the discoid architecture of cells. These orthogonal mechanisms of MT network reorganization highlight the existence of an intricate mechanical balance between motor activities of kinesins and dyneins that controls cell 3D architecture, mechanics, and cell-microenvironment interactions.
Collapse
Affiliation(s)
- Alexander S. Zhovmer
- Center
for Biologics Evaluation and Research, U.S.
Food and Drug Administration, Silver Spring, Maryland 20903, United States
- . Tel: 1-301-402-1606
| | - Alexis Manning
- Center
for Biologics Evaluation and Research, U.S.
Food and Drug Administration, Silver Spring, Maryland 20903, United States
| | - Chynna Smith
- Section
on Mechanobiology, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - James B. Hayes
- Department
of Cell and Developmental Biology, Vanderbilt Medical Center, University of Vanderbilt, Nashville, Tennessee 37232, United States
| | - Dylan T. Burnette
- Department
of Cell and Developmental Biology, Vanderbilt Medical Center, University of Vanderbilt, Nashville, Tennessee 37232, United States
| | - Jian Wang
- Department
of Pharmacology, Penn State College of Medicine, Pennsylvania State University, Hummelstown, Pennsylvania 17036, United States
| | - Alexander X. Cartagena-Rivera
- Section
on Mechanobiology, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
- . Tel: 1-301-503-4033
| | - Nikolay V. Dokholyan
- Department
of Pharmacology, Penn State College of Medicine, Pennsylvania State University, Hummelstown, Pennsylvania 17036, United States
- Department
of Biochemistry & Molecular Biology, Penn State College of Medicine, Pennsylvania State University, Hershey, Pennsylvania 17033, United States
- . Tel: 1-717-531-5177
| | - Rakesh K. Singh
- Department
of Obstetrics and Gynecology, University
of Rochester Medical Center, Rochester, New York 14620, United States
- . Tel: 1-585-276-6281
| | - Erdem D. Tabdanov
- Department
of Pharmacology, Penn State College of Medicine, Pennsylvania State University, Hummelstown, Pennsylvania 17036, United States
- . Tel: 1-717-531-0003 Ext: 4430
| |
Collapse
|
5
|
Taneja N, Baillargeon SM, Burnette DT. Myosin light chain kinase-driven myosin II turnover regulates actin cortex contractility during mitosis. Mol Biol Cell 2021; 32:br3. [PMID: 34319762 PMCID: PMC8684764 DOI: 10.1091/mbc.e20-09-0608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 07/02/2021] [Accepted: 07/19/2021] [Indexed: 11/11/2022] Open
Abstract
Force generation by the molecular motor myosin II (MII) at the actin cortex is a universal feature of animal cells. Despite its central role in driving cell shape changes, the mechanisms underlying MII regulation at the actin cortex remain incompletely understood. Here we show that myosin light chain kinase (MLCK) promotes MII turnover at the mitotic cortex. Inhibition of MLCK resulted in an alteration of the relative levels of phosphorylated regulatory light chain (RLC), with MLCK preferentially creating a short-lived pRLC species and Rho-associated kinase (ROCK) preferentially creating a stable ppRLC species during metaphase. Slower turnover of MII and altered RLC homeostasis on MLCK inhibition correlated with increased cortex tension, driving increased membrane bleb initiation and growth, but reduced bleb retraction during mitosis. Taken together, we show that ROCK and MLCK play distinct roles at the actin cortex during mitosis; ROCK activity is required for recruitment of MII to the cortex, while MLCK activity promotes MII turnover. Our findings support the growing evidence that MII turnover is an essential dynamic process influencing the mechanical output of the actin cortex.
Collapse
Affiliation(s)
- Nilay Taneja
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37212
| | - Sophie M. Baillargeon
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37212
| | - Dylan T. Burnette
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37212
| |
Collapse
|
6
|
Neininger AC, Dai X, Liu Q, Burnette DT. The Hippo pathway regulates density-dependent proliferation of iPSC-derived cardiac myocytes. Sci Rep 2021; 11:17759. [PMID: 34493746 PMCID: PMC8423799 DOI: 10.1038/s41598-021-97133-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/19/2021] [Indexed: 01/08/2023] Open
Abstract
Inducing cardiac myocytes to proliferate is considered a potential therapy to target heart disease, however, modulating cardiac myocyte proliferation has proven to be a technical challenge. The Hippo pathway is a kinase signaling cascade that regulates cell proliferation during the growth of the heart. Inhibition of the Hippo pathway increases the activation of the transcription factors YAP/TAZ, which translocate to the nucleus and upregulate transcription of pro-proliferative genes. The Hippo pathway regulates the proliferation of cancer cells, pluripotent stem cells, and epithelial cells through a cell-cell contact-dependent manner, however, it is unclear if cell density-dependent cell proliferation is a consistent feature in cardiac myocytes. Here, we used cultured human iPSC-derived cardiac myocytes (hiCMs) as a model system to investigate this concept. hiCMs have a comparable transcriptome to the immature cardiac myocytes that proliferate during heart development in vivo. Our data indicate that a dense syncytium of hiCMs can regain cell cycle activity and YAP expression and activity when plated sparsely or when density is reduced through wounding. We found that combining two small molecules, XMU-MP-1 and S1P, increased YAP activity and further enhanced proliferation of low-density hiCMs. Importantly, these compounds had no effect on hiCMs within a dense syncytium. These data add to a growing body of literature that link Hippo pathway regulation with cardiac myocyte proliferation and demonstrate that regulation is restricted to cells with reduced contact inhibition.
Collapse
Affiliation(s)
- Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
- Program in Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Xiaozhaun Dai
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Qi Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA.
- Program in Developmental Biology, Vanderbilt University, Nashville, TN, USA.
| |
Collapse
|
7
|
Taneja N, Bersi MR, Baillargeon SM, Fenix AM, Cooper JA, Ohi R, Gama V, Merryman WD, Burnette DT. Precise Tuning of Cortical Contractility Regulates Cell Shape during Cytokinesis. Cell Rep 2021; 31:107477. [PMID: 32268086 DOI: 10.1016/j.celrep.2020.03.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [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: 08/20/2019] [Revised: 01/27/2020] [Accepted: 03/13/2020] [Indexed: 01/30/2023] Open
Abstract
The mechanical properties of the actin cortex regulate shape changes during cell division, cell migration, and tissue morphogenesis. We show that modulation of myosin II (MII) filament composition allows tuning of surface tension at the cortex to maintain cell shape during cytokinesis. Our results reveal that MIIA generates cortex tension, while MIIB acts as a stabilizing motor and its inclusion in MII hetero-filaments reduces cortex tension. Tension generation by MIIA drives faster cleavage furrow ingression and bleb formation. We also show distinct roles for the motor and tail domains of MIIB in maintaining cytokinetic fidelity. Maintenance of cortical stability by the motor domain of MIIB safeguards against shape instability-induced chromosome missegregation, while its tail domain mediates cortical localization at the terminal stages of cytokinesis to mediate cell abscission. Because most non-muscle contractile systems are cortical, this tuning mechanism will likely be applicable to numerous processes driven by myosin-II contractility.
Collapse
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew R Bersi
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Sophie M Baillargeon
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - James A Cooper
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vivian Gama
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - W David Merryman
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
| |
Collapse
|
8
|
Taneja N, Bersi MR, Rasmussen ML, Gama V, Merryman WD, Burnette DT. Cover Image, Volume 77, Issue 9. Cytoskeleton (Hoboken) 2020. [DOI: 10.1002/cm.21636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology Vanderbilt University Nashville Tennessee USA
| | - Matthew R. Bersi
- Department of Biomedical Engineering Vanderbilt University Nashville Tennessee USA
| | - Megan L. Rasmussen
- Department of Cell and Developmental Biology Vanderbilt University Nashville Tennessee USA
| | - Vivian Gama
- Department of Cell and Developmental Biology Vanderbilt University Nashville Tennessee USA
| | - W. David Merryman
- Department of Biomedical Engineering Vanderbilt University Nashville Tennessee USA
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology Vanderbilt University Nashville Tennessee USA
| |
Collapse
|
9
|
Taneja N, Bersi MR, Rasmussen ML, Gama V, Merryman WD, Burnette DT. Inhibition of focal adhesion kinase increases myofibril viscosity in cardiac myocytes. Cytoskeleton (Hoboken) 2020; 77:342-350. [PMID: 32885903 DOI: 10.1002/cm.21632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 11/06/2022]
Abstract
The coordinated generation of mechanical forces by cardiac myocytes is required for proper heart function. Myofibrils are the functional contractile units of force production within individual cardiac myocytes. At the molecular level, myosin motors form cross-bridges with actin filaments and use ATP to convert chemical energy into mechanical forces. The energetic efficiency of the cross-bridge cycle is influenced by the viscous damping of myofibril contraction. The viscoelastic response of myofibrils is an emergent property of their individual mechanical components. Previous studies have implicated titin-actin interactions, cell-ECM adhesion, and microtubules as regulators of the viscoelastic response of myofibrils. Here we probed the viscoelastic response of myofibrils using laser-assisted dissection. As a proof-of-concept, we found actomyosin contractility was required to endow myofibrils with their viscoelastic response, with blebbistatin treatment resulting in decreased myofibril tension and viscous damping. Focal adhesion kinase (FAK) is a key regulator of cell-ECM adhesion, microtubule stability, and myofibril assembly. We found inhibition of FAK signaling altered the viscoelastic properties of myofibrils. Specifically, inhibition of FAK resulted in increased viscous damping of myofibril retraction following laser ablation. This damping was not associated with acute changes in the electrophysiological properties of cardiac myocytes. These results implicate FAK as a regulator of mechanical properties of myofibrils.
Collapse
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Matthew R Bersi
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Megan L Rasmussen
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Vivian Gama
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - W David Merryman
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
10
|
Taneja N, Neininger AC, Burnette DT. Coupling to substrate adhesions drives the maturation of muscle stress fibers into myofibrils within cardiomyocytes. Mol Biol Cell 2020; 31:1273-1288. [PMID: 32267210 PMCID: PMC7353145 DOI: 10.1091/mbc.e19-11-0652] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Forces generated by heart muscle contraction must be balanced by adhesion to the extracellular matrix (ECM) and to other cells for proper heart function. Decades of data have suggested that cell-ECM adhesions are important for sarcomere assembly. However, the relationship between cell-ECM adhesions and sarcomeres assembling de novo remains untested. Sarcomeres arise from muscle stress fibers (MSFs) that are translocating on the top (dorsal) surface of cultured cardiomyocytes. Using an array of tools to modulate cell-ECM adhesion, we established a strong positive correlation between the extent of cell-ECM adhesion and sarcomere assembly. On the other hand, we found a strong negative correlation between the extent of cell-ECM adhesion and the rate of MSF translocation, a phenomenon also observed in nonmuscle cells. We further find a conserved network architecture that also exists in nonmuscle cells. Taken together, our results show that cell-ECM adhesions mediate coupling between the substrate and MSFs, allowing their maturation into sarcomere-containing myofibrils.
Collapse
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| |
Collapse
|
11
|
Rasmussen ML, Taneja N, Neininger AC, Wang L, Robertson GL, Riffle SN, Shi L, Knollmann BC, Burnette DT, Gama V. MCL-1 Inhibition by Selective BH3 Mimetics Disrupts Mitochondrial Dynamics Causing Loss of Viability and Functionality of Human Cardiomyocytes. iScience 2020; 23:101015. [PMID: 32283523 PMCID: PMC7155208 DOI: 10.1016/j.isci.2020.101015] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 02/25/2020] [Accepted: 03/24/2020] [Indexed: 12/17/2022] Open
Abstract
MCL-1 is a well-characterized inhibitor of cell death that has also been shown to be a regulator of mitochondrial dynamics in human pluripotent stem cells. We used cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) to uncover whether MCL-1 is crucial for cardiac function and survival. Inhibition of MCL-1 by BH3 mimetics resulted in the disruption of mitochondrial morphology and dynamics as well as disorganization of the actin cytoskeleton. Interfering with MCL-1 function affects the homeostatic proximity of DRP-1 and MCL-1 at the outer mitochondrial membrane, resulting in decreased functionality of hiPSC-CMs. Cardiomyocytes display abnormal cardiac performance even after caspase inhibition, supporting a nonapoptotic activity of MCL-1 in hiPSC-CMs. BH3 mimetics targeting MCL-1 are promising anti-tumor therapeutics. Progression toward using BCL-2 family inhibitors, especially targeting MCL-1, depends on understanding its canonical function not only in preventing apoptosis but also in the maintenance of mitochondrial dynamics and function. BH3 mimetics targeting MCL-1 disrupt the mitochondrial network of human iPSC-CMs The BH3-mimetic-mediated effects on mitochondrial dynamics are DRP-1-dependent Targeting MCL-1 affects the survival and function of human cardiomyocytes Human iPSC-derived cardiomyocytes can be used to reveal toxicity of MCL-1 inhibitors
Collapse
Affiliation(s)
- Megan L Rasmussen
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Nilay Taneja
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Abigail C Neininger
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Lili Wang
- Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Nashville, TN 37232, USA
| | - Gabriella L Robertson
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Stellan N Riffle
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Linzheng Shi
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Bjorn C Knollmann
- Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Nashville, TN 37232, USA
| | - Dylan T Burnette
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Vivian Gama
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA.
| |
Collapse
|
12
|
Neininger AC, Long JH, Baillargeon SM, Burnette DT. A simple and flexible high-throughput method for the study of cardiomyocyte proliferation. Sci Rep 2019; 9:15917. [PMID: 31685907 PMCID: PMC6828730 DOI: 10.1038/s41598-019-52467-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/17/2019] [Indexed: 12/13/2022] Open
Abstract
Cardiac muscle cells lack regenerative capacity in postnatal mammals. A concerted effort has been made in the field to determine regulators of cardiomyocyte proliferation and identify therapeutic strategies to induce division, with the ultimate goal of regenerating heart tissue after a myocardial infarct. We sought to optimize a high throughput screening protocol to facilitate this effort. We developed a straight-forward high throughput screen with simple readouts to identify small molecules that modulate cardiomyocyte proliferation. We identify human induced pluripotent stem cell-derived cardiomyocytes (hiCMs) as a model system for such a screen, as a very small subset of hiCMs have the potential to proliferate. The ability of hiCMs to proliferate is density-dependent, and cell density has no effect on the outcome of proliferation: cytokinesis or binucleation. Screening a compound library revealed many regulators of proliferation and cell death. We provide a comprehensive and flexible screening procedure and cellular phenotype information for each compound. We then provide an example of steps to follow after this screen is performed, using three of the identified small molecules at various concentrations, further implicating their target kinases in cardiomyocyte proliferation. This screening platform is flexible and cost-effective, opening the field of cardiovascular cell biology to laboratories without substantial funding or specialized training, thus diversifying this scientific community.
Collapse
Affiliation(s)
- Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - J Hunter Long
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Sophie M Baillargeon
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA.
| |
Collapse
|
13
|
Neininger AC, Taneja N, Burnette DT. Abstract 337: Cell-Substrate Adhesion Regulates Early Steps of Myofibrillogenesis in Human Cardiomyocytes. Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Forces generated by myofibrils within cardiomyocytes must be balanced by adhesion to the extracellular matrix proteins and to other cardiomyocytes for proper heart function. Loss of this force balance results in cardiomyopathies and heart failure. Using a sarcomere assembly assay we previously developed utilizing human induced pluripotent stem cell-derived cardiomyocytes, we show coupling of focal adhesions to myofibrils during early steps of
de novo
myofibrillogenesis is essential for myofibril maturation. Increasing the extent of adhesion by inhibition of Focal adhesion kinase (FAK), a known regulator of adhesion dynamics, or by increasing the concentration of fibronectin on which the cardiomyocytes are cultured, led to precocious myofibril formation. Decreasing the extent of adhesion by siRNA-mediated FAK knockdown or by decreasing the concentration of fibronectin attenuated myofibrillogenesis. In each case, increased or decreased adhesion extent inversely correlated with rate of retrograde flow of myofibril precursors known as muscle stress fibers (AKA, non-muscle stress fiber-like structures or pre-myofibrils). This suggests a relationship between cell-substrate adhesion and substrate coupling to muscle stress fibers, facilitating their maturation into myofibrils. Taken together, our findings implicate a role for classical mechano-transduction in the assembly of sarcomere containing myofibrils.
Collapse
|
14
|
Burnette DT, Fenix AM, Neininger AC, Taneja N, Hyde K, Visetsouk MR, Garde R, Liu B, Nixon BR, Manalo AE, Becker JR, Crawley SW, Bader DM, Tyska MJ, Liu Q, Gutzman JH. Abstract 901: Muscle-specific Stress Fibers Give Rise to Sarcomeres in Cardiomyocytes. Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The sarcomere is the contractile unit that drives muscle contraction. Despite its importance, little is understood about how a disordered acto-myosin distribution converts into an ordered contractile array during sarcomere assembly. Here, we take advantage of a sarcomere assembly assay we developed using human induced pluripotent stem cell derived cardiomycytes to image the formation of sarcomeres, using live-cell high resolution microscopy. Our data show that a population of muscle specific stress fibers (MSFs) are essential sarcomere precursors. Interestingly, MSFs are formed at the leading edge of cells, undergo retrograde flow, and transition into sarcomere-containing myofibrils on the dorsal surface of cardiomyocytes. This is in direct contradiction to a recent report claiming sarcomeres are formed from adhesions on the ventral surface of cardiomyocytes. We have been able to recapitulate this other group's published experiments and definitively show that sarcomeres are not forming from the bottom of the cells or streaming out of adhesions. Instead, our 3D microscopy data shows that this group was imaging sarcomeres which were already formed on the dorsal surface and were traveling to the ventral surface of the cells. After this important clarification, we used our assay to show that the transition of MSFs to sarcomere-containing myofibrils requires formin-mediated actin polymerization and the non-muscle myosin IIA and myosin IIB. We conclude that sarcomeres form by a "templating" mechanism similar to that originally postulated by Howard Holtzer >30 years ago. Furthermore, our data show short β cardiac myosin II filaments are themselves templated by "non-muscle" myosin II filaments. Subsequently, the short β cardiac myosin II filaments grow to form ~1.5 μm long filaments that then “stitch” together to form the stack of filaments at the core of the sarcomere (i.e., the A-band). Taken together, our data show that the differentiation of cardiomyocytes from stem cells is a powerful tool for dissecting the mechanisms controlling sarcomere assembly.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Ryan Garde
- Vanderbilt Sch of Medicine, Nashville, TN
| | | | | | | | | | | | | | | | - Qi Liu
- Vanderbilt Sch of Medicine, Nashville, TN
| | | |
Collapse
|
15
|
Abstract
Membrane blebs are specialized cellular protrusions that play diverse roles in processes such as cell division and cell migration. Blebbing can be divided into three distinct phases: bleb nucleation, bleb growth, and bleb retraction. Following nucleation and bleb growth, the actin cortex, comprising actin, cross-linking proteins, and nonmuscle myosin II (MII), begins to reassemble on the membrane. MII then drives the final phase, bleb retraction, which results in reintegration of the bleb into the cellular cortex. There are three MII paralogues with distinct biophysical properties expressed in mammalian cells: MIIA, MIIB, and MIIC. Here we show that MIIA specifically drives bleb retraction during cytokinesis. The motor domain and regulation of the nonhelical tailpiece of MIIA both contribute to its ability to drive bleb retraction. These experiments have also revealed a relationship between faster turnover of MIIA at the cortex and its ability to drive bleb retraction.
Collapse
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| |
Collapse
|
16
|
Howard AM, LaFever KS, Fenix AM, Scurrah CR, Lau KS, Burnette DT, Bhave G, Ferrell N, Page-McCaw A. DSS-induced damage to basement membranes is repaired by matrix replacement and crosslinking. J Cell Sci 2019; 132:jcs.226860. [PMID: 30837285 DOI: 10.1242/jcs.226860] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 02/22/2019] [Indexed: 12/12/2022] Open
Abstract
Basement membranes are an ancient form of animal extracellular matrix. As important structural and functional components of tissues, basement membranes are subject to environmental damage and must be repaired while maintaining functions. Little is known about how basement membranes get repaired. This paucity stems from a lack of suitable in vivo models for analyzing such repair. Here, we show that dextran sodium sulfate (DSS) directly damages the gut basement membrane when fed to adult Drosophila DSS becomes incorporated into the basement membrane, promoting its expansion while decreasing its stiffness, which causes morphological changes to the underlying muscles. Remarkably, two days after withdrawal of DSS, the basement membrane is repaired by all measures of analysis. We used this new damage model to determine that repair requires collagen crosslinking and replacement of damaged components. Genetic and biochemical evidence indicates that crosslinking is required to stabilize the newly incorporated repaired Collagen IV rather than to stabilize the damaged Collagen IV. These results suggest that basement membranes are surprisingly dynamic.
Collapse
Affiliation(s)
- Angela M Howard
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kimberly S LaFever
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Cherie' R Scurrah
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ken S Lau
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Gautam Bhave
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Nicholas Ferrell
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235-1631, USA
| | - Andrea Page-McCaw
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA .,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| |
Collapse
|
17
|
Jeppesen DK, Fenix AM, Franklin JL, Higginbotham JN, Zhang Q, Zimmerman LJ, Liebler DC, Ping J, Liu Q, Evans R, Fissell WH, Patton JG, Rome LH, Burnette DT, Coffey RJ. Reassessment of Exosome Composition. Cell 2019; 177:428-445.e18. [PMID: 30951670 PMCID: PMC6664447 DOI: 10.1016/j.cell.2019.02.029] [Citation(s) in RCA: 1567] [Impact Index Per Article: 313.4] [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: 06/05/2018] [Revised: 10/08/2018] [Accepted: 02/15/2019] [Indexed: 12/13/2022]
Abstract
The heterogeneity of small extracellular vesicles and presence of non-vesicular extracellular matter have led to debate about contents and functional properties of exosomes. Here, we employ high-resolution density gradient fractionation and direct immunoaffinity capture to precisely characterize the RNA, DNA, and protein constituents of exosomes and other non-vesicle material. Extracellular RNA, RNA-binding proteins, and other cellular proteins are differentially expressed in exosomes and non-vesicle compartments. Argonaute 1-4, glycolytic enzymes, and cytoskeletal proteins were not detected in exosomes. We identify annexin A1 as a specific marker for microvesicles that are shed directly from the plasma membrane. We further show that small extracellular vesicles are not vehicles of active DNA release. Instead, we propose a new model for active secretion of extracellular DNA through an autophagy- and multivesicular-endosome-dependent but exosome-independent mechanism. This study demonstrates the need for a reassessment of exosome composition and offers a framework for a clearer understanding of extracellular vesicle heterogeneity.
Collapse
Affiliation(s)
- Dennis K Jeppesen
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jeffrey L Franklin
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Veterans Affairs Medical Center, Nashville, TN 37232, USA
| | - James N Higginbotham
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Qin Zhang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Lisa J Zimmerman
- Jim Ayers Institute for Precancer Detection and Diagnosis, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daniel C Liebler
- Jim Ayers Institute for Precancer Detection and Diagnosis, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jie Ping
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Qi Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel Evans
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - William H Fissell
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - James G Patton
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Leonard H Rome
- Department of Biological Chemistry, David Geffen School of Medicine and the California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Robert J Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Veterans Affairs Medical Center, Nashville, TN 37232, USA.
| |
Collapse
|
18
|
Taneja N, Rathbun L, Hehnly H, Burnette DT. The balance between adhesion and contraction during cell division. Curr Opin Cell Biol 2019; 56:45-52. [PMID: 30268802 PMCID: PMC6363874 DOI: 10.1016/j.ceb.2018.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 06/30/2018] [Revised: 07/26/2018] [Accepted: 09/03/2018] [Indexed: 12/24/2022]
Abstract
The ability to divide is a fundamental property of a living cell. The 3D orientation of cell division is essential for embryogenesis, maintenance of tissue organization and architecture, as well as controlling cell fate. Much attention has been placed on the mitotic spindle's role in placing itself along the cell's longest axis, where a shape sensing mechanism between a population of microtubules extending from mitotic centrosomes to the cell cortex occurs. However, contractile forces at the cell cortex also likely play a decisive role in determining the final placement of daughter cells following division. In this review, we discuss recent literature that describes the role of these contractile forces and how these forces could be balanced by mitotic adhesion complexes.
Collapse
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lindsay Rathbun
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Heidi Hehnly
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| |
Collapse
|
19
|
Fenix AM, Burnette DT. Cover Image, Volume 75, Issue 12. Cytoskeleton (Hoboken) 2019. [DOI: 10.1002/cm.21512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Aidan M. Fenix
- Department of Cell and Developmental Biology Vanderbilt University School of Medicine Nashville Tennessee
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology Vanderbilt University School of Medicine Nashville Tennessee
| |
Collapse
|
20
|
Jiu Y, Kumari R, Fenix AM, Schaible N, Liu X, Varjosalo M, Krishnan R, Burnette DT, Lappalainen P. Myosin-18B Promotes the Assembly of Myosin II Stacks for Maturation of Contractile Actomyosin Bundles. Curr Biol 2018; 29:81-92.e5. [PMID: 30581023 DOI: 10.1016/j.cub.2018.11.045] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/12/2018] [Accepted: 11/16/2018] [Indexed: 10/27/2022]
Abstract
Cell adhesion, morphogenesis, mechanosensing, and muscle contraction rely on contractile actomyosin bundles, where the force is produced through sliding of bipolar myosin II filaments along actin filaments. The assembly of contractile actomyosin bundles involves registered alignment of myosin II filaments and their subsequent fusion into large stacks. However, mechanisms underlying the assembly of myosin II stacks and their physiological functions have remained elusive. Here, we identified myosin-18B, an unconventional myosin, as a stable component of contractile stress fibers. Myosin-18B co-localized with myosin II motor domains in stress fibers and was enriched at the ends of myosin II stacks. Importantly, myosin-18B deletion resulted in drastic defects in the concatenation and persistent association of myosin II filaments with each other and thus led to severely impaired assembly of myosin II stacks. Consequently, lack of myosin-18B resulted in defective maturation of actomyosin bundles from their precursors in osteosarcoma cells. Moreover, myosin-18B knockout cells displayed abnormal morphogenesis, migration, and ability to exert forces to the environment. These results reveal a critical role for myosin-18B in myosin II stack assembly and provide evidence that myosin II stacks are important for a variety of vital processes in cells.
Collapse
Affiliation(s)
- Yaming Jiu
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland; CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Reena Kumari
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Niccole Schaible
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Xiaonan Liu
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | - Ramaswamy Krishnan
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland.
| |
Collapse
|
21
|
Fenix AM, Neininger AC, Taneja N, Hyde K, Visetsouk MR, Garde RJ, Liu B, Nixon BR, Manalo AE, Becker JR, Crawley SW, Bader DM, Tyska MJ, Liu Q, Gutzman JH, Burnette DT. Muscle-specific stress fibers give rise to sarcomeres in cardiomyocytes. eLife 2018; 7:42144. [PMID: 30540249 PMCID: PMC6307863 DOI: 10.7554/elife.42144] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
The sarcomere is the contractile unit within cardiomyocytes driving heart muscle contraction. We sought to test the mechanisms regulating actin and myosin filament assembly during sarcomere formation. Therefore, we developed an assay using human cardiomyocytes to monitor sarcomere assembly. We report a population of muscle stress fibers, similar to actin arcs in non-muscle cells, which are essential sarcomere precursors. We show sarcomeric actin filaments arise directly from muscle stress fibers. This requires formins (e.g., FHOD3), non-muscle myosin IIA and non-muscle myosin IIB. Furthermore, we show short cardiac myosin II filaments grow to form ~1.5 μm long filaments that then 'stitch' together to form the stack of filaments at the core of the sarcomere (i.e., the A-band). A-band assembly is dependent on the proper organization of actin filaments and, as such, is also dependent on FHOD3 and myosin IIB. We use this experimental paradigm to present evidence for a unifying model of sarcomere assembly.
Collapse
Affiliation(s)
- Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Karren Hyde
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Mike R Visetsouk
- Department of Biological Sciences, Cell and Molecular Biology, University of Wisconsin Milwaukee, Milwaukee, United States
| | - Ryan J Garde
- Department of Biological Sciences, Cell and Molecular Biology, University of Wisconsin Milwaukee, Milwaukee, United States
| | - Baohong Liu
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Benjamin R Nixon
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States
| | - Annabelle E Manalo
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Jason R Becker
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States
| | - Scott W Crawley
- Department of Biological Sciences, The University of Toledo, Toledo, United States
| | - David M Bader
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Qi Liu
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Jennifer H Gutzman
- Department of Biological Sciences, Cell and Molecular Biology, University of Wisconsin Milwaukee, Milwaukee, United States
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| |
Collapse
|
22
|
Pathak A, Stanley EM, Hickman FE, Wallace N, Brewer B, Li D, Gluska S, Perlson E, Fuhrmann S, Akassoglou K, Bronfman F, Casaccia P, Burnette DT, Carter BD. Retrograde Degenerative Signaling Mediated by the p75 Neurotrophin Receptor Requires p150 Glued Deacetylation by Axonal HDAC1. Dev Cell 2018; 46:376-387.e7. [PMID: 30086304 DOI: 10.1016/j.devcel.2018.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [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: 01/28/2017] [Revised: 05/19/2018] [Accepted: 07/01/2018] [Indexed: 12/23/2022]
Abstract
During development, neurons undergo apoptosis if they do not receive adequate trophic support from tissues they innervate or when detrimental factors activate the p75 neurotrophin receptor (p75NTR) at their axon ends. Trophic factor deprivation (TFD) or activation of p75NTR in distal axons results in a retrograde degenerative signal. However, the nature of this signal and the regulation of its transport are poorly understood. Here, we identify p75NTR intracellular domain (ICD) and histone deacetylase 1 (HDAC1) as part of a retrograde pro-apoptotic signal generated in response to TFD or ligand binding to p75NTR in sympathetic neurons. We report an unconventional function of HDAC1 in retrograde transport of a degenerative signal and its constitutive presence in sympathetic axons. HDAC1 deacetylates dynactin subunit p150Glued, which enhances its interaction with dynein. These findings define p75NTR ICD as a retrograde degenerative signal and reveal p150Glued deacetylation as a unique mechanism regulating axonal transport.
Collapse
Affiliation(s)
- Amrita Pathak
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Emily M Stanley
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - F Edward Hickman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Natalie Wallace
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Bryson Brewer
- Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Deyu Li
- Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Shani Gluska
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Sabine Fuhrmann
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Katerina Akassoglou
- Gladstone Institute of Neurological Disease and Department of Neurology, University of California, San Francisco, CA, USA
| | - Francisca Bronfman
- Center for Ageing and Regeneration (CARE UC), Faculty of Biological Sciences, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Patrizia Casaccia
- Hunter College Department of Biology, Advanced Science Research Center at The Graduate Center of the City University of New York, New York, NY, USA
| | - Dylan T Burnette
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Bruce D Carter
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
| |
Collapse
|
23
|
Fenix AM, Burnette DT. Assembly of myosin II filament arrays: Network Contraction versus Expansion. Cytoskeleton (Hoboken) 2018; 75:545-549. [PMID: 30126071 DOI: 10.1002/cm.21487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/31/2018] [Accepted: 08/13/2018] [Indexed: 12/18/2022]
Abstract
How cellular contractile systems assemble has fascinated scientists for generations. The major molecule responsible for cellular force generation is the molecular motor, non-muscle myosin II (NMII). NMII molecules are organized into single myosin filaments and larger arrays of filaments called NMII stacks, which are capable of generating increasing amounts of force. The textbook model of NMII stack assembly is the Network Contraction Model, where ensembles of distinct NMII filaments condense into a NMII stack by pulling on actin filaments. While this model has been widely accepted for ~20 years, it has been difficult to test inside cells due to the small size of NMII filaments. Recently, interest in how NMII stacks form has been reinvigorated by the advent of super-resolution microscopy techniques which have afforded unprecedented resolution of NMII filaments inside cells. A number of recent publications using these techniques have called into question key aspects of the Network Contraction Model, and our understanding of how NMII stacks assemble.
Collapse
Affiliation(s)
- Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| |
Collapse
|
24
|
Lehtimäki JI, Fenix AM, Kotila TM, Balistreri G, Paavolainen L, Varjosalo M, Burnette DT, Lappalainen P. UNC-45a promotes myosin folding and stress fiber assembly. J Cell Biol 2017; 216:4053-4072. [PMID: 29055011 PMCID: PMC5716280 DOI: 10.1083/jcb.201703107] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/28/2017] [Accepted: 09/19/2017] [Indexed: 12/15/2022] Open
Abstract
Contractile actomyosin bundles, stress fibers, are crucial for adhesion, morphogenesis, and mechanosensing in nonmuscle cells. However, the mechanisms by which nonmuscle myosin II (NM-II) is recruited to those structures and assembled into functional bipolar filaments have remained elusive. We report that UNC-45a is a dynamic component of actin stress fibers and functions as a myosin chaperone in vivo. UNC-45a knockout cells display severe defects in stress fiber assembly and consequent abnormalities in cell morphogenesis, polarity, and migration. Experiments combining structured-illumination microscopy, gradient centrifugation, and proteasome inhibition approaches revealed that a large fraction of NM-II and myosin-1c molecules fail to fold in the absence of UNC-45a. The remaining properly folded NM-II molecules display defects in forming functional bipolar filaments. The C-terminal UNC-45/Cro1/She4p domain of UNC-45a is critical for NM-II folding, whereas the N-terminal tetratricopeptide repeat domain contributes to the assembly of functional stress fibers. Thus, UNC-45a promotes generation of contractile actomyosin bundles through synchronized NM-II folding and filament-assembly activities.
Collapse
Affiliation(s)
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Tommi M Kotila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Giuseppe Balistreri
- Department of Biosciences, Division of General Microbiology, University of Helsinki, Helsinki, Finland
| | - Lassi Paavolainen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| |
Collapse
|
25
|
Guo M, Pegoraro AF, Mao A, Zhou EH, Arany PR, Han Y, Burnette DT, Jensen MH, Kasza KE, Moore JR, Mackintosh FC, Fredberg JJ, Mooney DJ, Lippincott-Schwartz J, Weitz DA. Cell volume change through water efflux impacts cell stiffness and stem cell fate. Proc Natl Acad Sci U S A 2017; 114:E8618-E8627. [PMID: 28973866 PMCID: PMC5642688 DOI: 10.1073/pnas.1705179114] [Citation(s) in RCA: 261] [Impact Index Per Article: 37.3] [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] [Indexed: 12/24/2022] Open
Abstract
Cells alter their mechanical properties in response to their local microenvironment; this plays a role in determining cell function and can even influence stem cell fate. Here, we identify a robust and unified relationship between cell stiffness and cell volume. As a cell spreads on a substrate, its volume decreases, while its stiffness concomitantly increases. We find that both cortical and cytoplasmic cell stiffness scale with volume for numerous perturbations, including varying substrate stiffness, cell spread area, and external osmotic pressure. The reduction of cell volume is a result of water efflux, which leads to a corresponding increase in intracellular molecular crowding. Furthermore, we find that changes in cell volume, and hence stiffness, alter stem-cell differentiation, regardless of the method by which these are induced. These observations reveal a surprising, previously unidentified relationship between cell stiffness and cell volume that strongly influences cell biology.
Collapse
Affiliation(s)
- Ming Guo
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Adrian F Pegoraro
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Angelo Mao
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138
| | - Enhua H Zhou
- Harvard T. H. Chan School of Public Health, Boston, MA 02115
| | - Praveen R Arany
- Department of Oral Biology, University at Buffalo, Buffalo, NY 14214
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14214
| | - Yulong Han
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
- Biomedical Engineering and Biomechanics Center, Xi'an Jiaotong University, Xi'an 710049, China
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Mikkel H Jensen
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
- Department of Physics and Astronomy, California State University, Sacramento, CA 95819
| | - Karen E Kasza
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
- Department of Mechanical Engineering, Columbia University, New York, NY 10027
| | - Jeffrey R Moore
- Department of Biological Sciences, University of Massachusetts at Lowell, Lowell, MA 01854
| | - Frederick C Mackintosh
- Department of Physics and Astronomy, VU University, 1081 HV Amsterdam, The Netherlands
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77030
- Center for Theoretical Biophysics, Rice University, Houston, TX 77030
| | | | - David J Mooney
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138
| | | | - David A Weitz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
- Department of Physics, Harvard University, Cambridge, MA 02138
| |
Collapse
|
26
|
Burnette DT, Fenix A, Taneja N, Williams A, Bader D, Gutzman J, Tyska M. Abstract 390: Actin Arcs are Essential Templates for Sarcomere Assembly in Cardiomyocytes. Circ Res 2017. [DOI: 10.1161/res.121.suppl_1.390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The sarcomere is the basic contractile unit within cardiomyocytes. The proper assembly of sarcomeres during development and their maintenance during homeostasis are critical for the contraction of the heart. How molecular components of sarcomeres assemble remains a major unanswered question. Here we use newly plated
h
uman
i
nduced pluripotent stem cell-derived
c
ardio
m
yocytes (hiCM) combined with high-resolution microscopy to elucidate the steps of
de novo
sarcomere assembly. We found that sarcomere formation was preceded by bundles of actin filaments resembling the so-called “actin arcs” prevalent in migrating non-muscle cells. Live-cell imaging revealed that sarcomeres appeared along the length of actin arcs; suggesting they are acting as a template for sarcomere assembly. Actin arc formation in non-muscle cells is dependent on the actin filament nucleator, formin, and the molecular motor,
n
on-muscle
m
yosin
II
(NMII). Inhibiting formin with the small molecule SMIFH2 in hiCM stopped the formation of actin arcs and subsequent sarcomere assembly, but had no effect on pre-assembled sarcomeres. We found that two isoforms of NMII, NMIIA and NMIIB, localized to the actin arcs in hiCM. Knockdown of NMIIB, but not NMIIA, in hiCM resulted in a loss of sarcomere assembly, but, much like formin inhibition, did not affect pre-assembled sarcomeres. To test if loss of NMIIB resulted in less sarcomere assembly
in vivo
, we knocked down NMIIB in zebrafish embryos, and found a significant loss of sarcomeres within both the atrium and ventricle. Finally, we use super-resolution microscopy to show that NMII and the muscle isoform,
β
m
yosin
II
(βMII), are found in the same filaments in hiCM and
in vivo
in neonatal mice and in human patients with hypertrophic cardiomyopathy, suggesting individual molecular components within actin arcs (e.g., NMII) could be acting as seeds for their muscle counterparts (e.g., βMII). Taken together, our data supports a model in which contractile systems in cardiomyocytes evolved from non-muscle contractile systems. Furthermore, cardiomyocytes still use some non-muscle contractile components for sarcomere assembly during development, and potentially during aberrant sarcomere formation during hypertrophic cardiomyopathy.
Collapse
|
27
|
Balikov DA, Crowder SW, Boire TC, Lee JB, Gupta MK, Fenix AM, Lewis HN, Ambrose CM, Short PA, Kim CS, Burnette DT, Reilly MA, Murthy NS, Kang ML, Kim WS, Sung HJ. Tunable Surface Repellency Maintains Stemness and Redox Capacity of Human Mesenchymal Stem Cells. ACS Appl Mater Interfaces 2017; 9:22994-23006. [PMID: 28621931 PMCID: PMC5687519 DOI: 10.1021/acsami.7b06103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Human bone marrow derived mesenchymal stem cells (hMSCs) hold great promise for regenerative medicine due to their multipotent differentiation capacity and immunomodulatory capabilities. Substantial research has elucidated mechanisms by which extracellular cues regulate hMSC fate decisions, but considerably less work has addressed how material properties can be leveraged to maintain undifferentiated stem cells. Here, we show that synthetic culture substrates designed to exhibit moderate cell-repellency promote high stemness and low oxidative stress-two indicators of naïve, healthy stem cells-in commercial and patient-derived hMSCs. Furthermore, the material-mediated effect on cell behavior can be tuned by altering the molar percentage (mol %) and/or chain length of poly(ethylene glycol) (PEG), the repellant block linked to hydrophobic poly(ε-caprolactone) (PCL) in the copolymer backbone. Nano- and angstrom-scale characterization of the cell-material interface reveals that PEG interrupts the adhesive PCL domains in a chain-length-dependent manner; this prevents hMSCs from forming mature focal adhesions and subsequently promotes cell-cell adhesions that require connexin-43. This study is the first to demonstrate that intrinsic properties of synthetic materials can be tuned to regulate the stemness and redox capacity of hMSCs and provides new insight for designing highly scalable, programmable culture platforms for clinical translation.
Collapse
Affiliation(s)
- Daniel A. Balikov
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Spencer W. Crowder
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Timothy C. Boire
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jung Bok Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Mukesh K. Gupta
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Aidan M. Fenix
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Holley N. Lewis
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Caitlyn M. Ambrose
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Philip A. Short
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Chang Soo Kim
- Department of Materials Science and Engineering, University of Wisconsin, Milwaukee, Wisconsin 53211, United States
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Matthew A. Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - N. Sanjeeva Murthy
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Mi-Lan Kang
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
| | - Won Shik Kim
- Department of Otorhinolaryngology, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
| | - Hak-Joon Sung
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
| |
Collapse
|
28
|
Taneja N, Fenix AM, Rathbun L, Millis BA, Tyska MJ, Hehnly H, Burnette DT. Focal adhesions control cleavage furrow shape and spindle tilt during mitosis. Sci Rep 2016; 6:29846. [PMID: 27432211 PMCID: PMC4949487 DOI: 10.1038/srep29846] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/24/2016] [Indexed: 01/01/2023] Open
Abstract
The geometry of the cleavage furrow during mitosis is often asymmetric in vivo and plays a critical role in stem cell differentiation and the relative positioning of daughter cells during development. Early observations of adhesive cell lines revealed asymmetry in the shape of the cleavage furrow, where the bottom (i.e., substrate attached side) of the cleavage furrow ingressed less than the top (i.e., unattached side). This data suggested substrate attachment could be regulating furrow ingression. Here we report a population of mitotic focal adhesions (FAs) controls the symmetry of the cleavage furrow. In single HeLa cells, stronger adhesion to the substrate directed less ingression from the bottom of the cell through a pathway including paxillin, focal adhesion kinase (FAK) and vinculin. Cell-cell contacts also direct ingression of the cleavage furrow in coordination with FAs in epithelial cells-MDCK-within monolayers and polarized cysts. In addition, mitotic FAs established 3D orientation of the mitotic spindle and the relative positioning of mother and daughter centrosomes. Therefore, our data reveals mitotic FAs as a key link between mitotic cell shape and spindle orientation, and may have important implications in our understanding stem cell homeostasis and tumorigenesis.
Collapse
Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Aidan M. Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lindsay Rathbun
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Bryan A. Millis
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Heidi Hehnly
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| |
Collapse
|
29
|
Fenix AM, Taneja N, Buttler CA, Lewis J, Van Engelenburg SB, Ohi R, Burnette DT. Expansion and concatenation of non-muscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis. Mol Biol Cell 2016; 27:mbc.E15-10-0725. [PMID: 26960797 PMCID: PMC4850034 DOI: 10.1091/mbc.e15-10-0725] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/25/2016] [Accepted: 03/01/2016] [Indexed: 11/19/2022] Open
Abstract
Cell movement and cytokinesis are facilitated by contractile forces generated by the molecular motor, non-muscle myosin II (NMII). NMII molecules form a filament (NMII-F) through interactions of their C-terminal rod domains, positioning groups of N-terminal motor domains on opposite sides. The NMII motors then bind and pull actin filaments toward the NMII-F, thus driving contraction. Inside of crawling cells, NMIIA-Fs form large macromolecular ensembles (i.e., NMIIA-F stacks) but how this occurs is unknown. Here we show NMIIA-F stacks are formed through two non-mutually exclusive mechanisms: expansion and concatenation. During expansion, NMIIA molecules within the NMIIA-F spread out concurrent with addition of new NMIIA molecules. Concatenation occurs when multiple NMIIA-F/NMIIA-F stacks move together and align. We found NMIIA-F stack formation was regulated by both motor-activity and the availability of surrounding actin filaments. Furthermore, our data showed expansion and concatenation also formed the contractile ring in dividing cells. Thus, interphase and mitotic cells share similar mechanisms for creating large contractile units, and these are likely to underlie how other myosin II-based contractile systems are assembled.
Collapse
Affiliation(s)
- Aidan M Fenix
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Nilay Taneja
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | | | - John Lewis
- Vanderbilt University School of Medicine, Nashville, TN 37232 Kalamazoo College, Kalamazoo, MI 49008
| | | | - Ryoma Ohi
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | | |
Collapse
|
30
|
Abstract
A migrating cell must establish front-to-back polarity in order to move. In this issue, Juanes-Garcia et al. (2015. J. Cell Biol.http://dx.doi.org/10.1083/jcb.201407059) report that a short serine-rich motif in nonmuscle myosin IIB is required to establish the cell’s rear. This motif represents a new paradigm for what determines directional cell migration.
Collapse
Affiliation(s)
- Aidan M Fenix
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | | |
Collapse
|
31
|
Abstract
Primary cilia are ubiquitous, microtubule-based organelles that play diverse roles in sensory transduction in many eukaryotic cells. They interrogate the cellular environment through chemosensing, osmosensing, and mechanosensing using receptors and ion channels in the ciliary membrane. Little is known about the mechanical and structural properties of the cilium and how these properties contribute to ciliary perception. We probed the mechanical responses of primary cilia from kidney epithelial cells [Madin-Darby canine kidney-II (MDCK-II)], which sense fluid flow in renal ducts. We found that, on manipulation with an optical trap, cilia deflect by bending along their length and pivoting around an effective hinge located below the basal body. The calculated bending rigidity indicates weak microtubule doublet coupling. Primary cilia of MDCK cells lack interdoublet dynein motors. Nevertheless, we found that the organelles display active motility. 3D tracking showed correlated fluctuations of the cilium and basal body. These angular movements seemed random but were dependent on ATP and cytoplasmic myosin-II in the cell cortex. We conclude that force generation by the actin cytoskeleton surrounding the basal body results in active ciliary movement. We speculate that actin-driven ciliary movement might tune and calibrate ciliary sensory functions.
Collapse
Affiliation(s)
- Christopher Battle
- Drittes Physikalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany
| | - Carolyn M Ott
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892; and
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt Medical Center, Nashville, TN 37232
| | - Jennifer Lippincott-Schwartz
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892; and
| | - Christoph F Schmidt
- Drittes Physikalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany;
| |
Collapse
|
32
|
Burnette DT, Shao L, Ott C, Pasapera AM, Fischer RS, Baird MA, Der Loughian C, Delanoe-Ayari H, Paszek MJ, Davidson MW, Betzig E, Lippincott-Schwartz J. A contractile and counterbalancing adhesion system controls the 3D shape of crawling cells. ACTA ACUST UNITED AC 2014; 205:83-96. [PMID: 24711500 PMCID: PMC3987145 DOI: 10.1083/jcb.201311104] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
How adherent and contractile systems coordinate to promote cell shape changes is unclear. Here, we define a counterbalanced adhesion/contraction model for cell shape control. Live-cell microscopy data showed a crucial role for a contractile meshwork at the top of the cell, which is composed of actin arcs and myosin IIA filaments. The contractile actin meshwork is organized like muscle sarcomeres, with repeating myosin II filaments separated by the actin bundling protein α-actinin, and is mechanically coupled to noncontractile dorsal actin fibers that run from top to bottom in the cell. When the meshwork contracts, it pulls the dorsal fibers away from the substrate. This pulling force is counterbalanced by the dorsal fibers' attachment to focal adhesions, causing the fibers to bend downward and flattening the cell. This model is likely to be relevant for understanding how cells configure themselves to complex surfaces, protrude into tight spaces, and generate three-dimensional forces on the growth substrate under both healthy and diseased conditions.
Collapse
Affiliation(s)
- Dylan T Burnette
- National Institute of Child Health and Human Development and 2 National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
For more than 100 years, the ultimate resolution of a light microscope (∼ 200 nm) has been constrained by the fundamental physical phenomenon of diffraction, as described by Ernst Abbe in 1873. While this limitation is just as applicable to today's light microscopes, it is the combination of high-end optics, clever methods of sample illumination, and computational techniques that has enabled researchers to access information at an order of magnitude greater resolution than once thought possible. This combination, broadly termed superresolution microscopy, has been increasingly practical for many labs to implement from both a hardware and software standpoint, but, as with many cutting-edge techniques, it also comes with limitations. One of the current drawbacks to superresolution microscopy is the limited number of probes and conditions that have been suitable for imaging. Here, a technique termed bleaching/blinking-assisted localization microscopy (BaLM) makes use of the inherent blinking and bleaching properties of almost all fluorophores as a means to generate superresolution images.
Collapse
Affiliation(s)
- Bryan A Millis
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| | - Dylan T Burnette
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Jennifer Lippincott-Schwartz
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Bechara Kachar
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
34
|
Burnette DT, Ji L, Schaefer AW, Medeiros NA, Danuser G, Forscher P. Myosin II activity facilitates microtubule bundling in the neuronal growth cone neck. Dev Cell 2008; 15:163-9. [PMID: 18606149 DOI: 10.1016/j.devcel.2008.05.016] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 05/21/2008] [Accepted: 05/30/2008] [Indexed: 01/20/2023]
Abstract
The cell biological processes underlying axon growth and guidance are still not well understood. An outstanding question is how a new segment of the axon shaft is formed in the wake of neuronal growth cone advance. For this to occur, the highly dynamic, splayed-out microtubule (MT) arrays characteristic of the growth cone must be consolidated (bundled together) to form the core of the axon shaft. MT-associated proteins stabilize bundled MTs, but how individual MTs are brought together for initial bundling is unknown. Here, we show that laterally moving actin arcs, which are myosin II-driven contractile structures, interact with growing MTs and transport them from the sides of the growth cone into the central domain. Upon Myosin II inhibition, the movement of actin filaments and MTs immediately stopped and MTs unbundled. Thus, Myosin II-dependent compressive force is necessary for normal MT bundling in the growth cone neck.
Collapse
Affiliation(s)
- Dylan T Burnette
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | | | | | | | | | | |
Collapse
|
35
|
Qin H, Burnette DT, Bae YK, Forscher P, Barr MM, Rosenbaum JL. Intraflagellar transport is required for the vectorial movement of TRPV channels in the ciliary membrane. Curr Biol 2006; 15:1695-9. [PMID: 16169494 DOI: 10.1016/j.cub.2005.08.047] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 08/01/2005] [Accepted: 08/09/2005] [Indexed: 11/26/2022]
Abstract
The membranes of all eukaryotic motile (9 + 2) and immotile primary (9 + 0) cilia harbor channels and receptors involved in sensory transduction (reviewed by). These membrane proteins are transported from the cytoplasm onto the ciliary membrane by vesicles targeted for exocytosis at a point adjacent to the ciliary basal body. Here, we use time-lapse fluorescence microscopy to demonstrate that select GFP-tagged sensory receptors undergo rapid vectorial transport along the entire length of the cilia of Caenorhabditis elegans sensory neurons. Transient receptor potential vanilloid (TRPV) channels OSM-9 and OCR-2 move in ciliary membranes at rates comparable to the intraflagellar transport (IFT) machinery located between the membrane and the underlying axonemal microtubules. OSM-9 motility is disrupted in certain IFT mutant backgrounds. Surprisingly, motility of transient receptor potential polycystin (TRPP) channel PKD-2 (polycystic kidney disease-2), a mechano-receptor, was not detected. Our study demonstrates that IFT, previously shown to be necessary for transport of axonemal components, is also involved in the motility of TRPV membrane protein movement along cilia of C. elegans sensory cells.
Collapse
Affiliation(s)
- Hongmin Qin
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
| | | | | | | | | | | |
Collapse
|
36
|
Medeiros NA, Burnette DT, Forscher P. Myosin II functions in actin-bundle turnover in neuronal growth cones. Nat Cell Biol 2006; 8:215-26. [PMID: 16501565 DOI: 10.1038/ncb1367] [Citation(s) in RCA: 364] [Impact Index Per Article: 20.2] [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: 11/24/2005] [Accepted: 02/02/2006] [Indexed: 12/30/2022]
Abstract
Retrograde actin flow works in concert with cell adhesion to generate traction forces that are involved in axon guidance in neuronal growth cones. Myosins have been implicated in retrograde flow, but identification of the specific myosin subtype(s) involved has been controversial. Using fluorescent speckle microscopy (FSM) to assess actin dynamics, we report that inhibition of myosin II alone decreases retrograde flow by 51% and the remaining flow can be almost fully accounted for by the 'push' of plus-end actin assembly at the leading edge of the growth cone. Interestingly, actin bundles that are associated with filopodium roots elongated by approximately 83% after inhibition of myosin II. This unexpected result was due to decreased rates of actin-bundle severing near their proximal (minus or pointed) ends which are located in the transition zone of the growth cone. Our study reveals a mechanism for the regulation of actin-bundle length by myosin II that is dependent on actin-bundle severing, and demonstrate that retrograde flow is a steady state that depends on both myosin II contractility and actin-network treadmilling.
Collapse
Affiliation(s)
- Nelson A Medeiros
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | | | | |
Collapse
|
37
|
Matroule JY, Lam H, Burnette DT, Jacobs-Wagner C. Cytokinesis monitoring during development; rapid pole-to-pole shuttling of a signaling protein by localized kinase and phosphatase in Caulobacter. Cell 2004; 118:579-90. [PMID: 15339663 DOI: 10.1016/j.cell.2004.08.019] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [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: 05/11/2004] [Revised: 07/16/2004] [Accepted: 07/21/2004] [Indexed: 10/26/2022]
Abstract
For successful generation of different cell types by asymmetric cell division, cell differentiation should be initiated only after completion of division. Here, we describe a control mechanism by which Caulobacter couples the initiation of a developmental program to the completion of cytokinesis. Genetic evidence indicates that localization of the signaling protein DivK at the flagellated pole prevents premature initiation of development. Photobleaching and FRET experiments show that polar localization of DivK is dynamic with rapid pole-to-pole shuttling of diffusible DivK generated by the localized activities of PleC phosphatase and DivJ kinase at opposite poles. This shuttling is interrupted upon completion of cytokinesis by the segregation of PleC and DivJ to different daughter cells, resulting in disruption of DivK localization at the flagellated pole and subsequent initiation of development in the flagellated progeny. Thus, dynamic polar localization of a diffusible protein provides a control mechanism that monitors cytokinesis to regulate development.
Collapse
Affiliation(s)
- Jean-Yves Matroule
- Department of Molecular, Cellular, and Developmental Biology, Yale University, P.O. Box 208103, New Haven, CT 06520, USA
| | | | | | | |
Collapse
|
38
|
Zhang XF, Schaefer AW, Burnette DT, Schoonderwoert VT, Forscher P. Rho-Dependent Contractile Responses in the Neuronal Growth Cone Are Independent of Classical Peripheral Retrograde Actin Flow. Neuron 2003; 40:931-44. [PMID: 14659092 DOI: 10.1016/s0896-6273(03)00754-2] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [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] [Indexed: 12/19/2022]
Abstract
Rho family GTPases have been implicated in neuronal growth cone guidance; however, the underlying cytoskeletal mechanisms are unclear. We have used multimode fluorescent speckle microscopy (FSM) to directly address this problem. We report that actin arcs that form in the transition zone are incorporated into central actin bundles in the C domain. These actin structures are Rho/Rho Kinase (ROCK) effectors. Specifically, LPA mediates growth cone retraction by ROCK-dependent increases in actin arc and central actin bundle contractility and stability. In addition, these treatments had marked effects on MT organization as a consequence of strong MT-actin arc interactions. In contrast, LPA or constitutively active Rho had no effect on P domain retrograde actin flow or filopodium bundle number. This study reveals a novel mechanism for domain-specific spatial control of actin-based motility in the growth cone with implications for understanding chemorepellant growth cone responses and nerve regeneration.
Collapse
Affiliation(s)
- Xiao-Feng Zhang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | | | | | | | | |
Collapse
|