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Scott AK, Casas E, Schneider SE, Swearingen AR, Van Den Elzen CL, Seelbinder B, Barthold JE, Kugel JF, Stern JL, Foster KJ, Emery NC, Brumbaugh J, Neu CP. Mechanical memory stored through epigenetic remodeling reduces cell therapeutic potential. Biophys J 2023; 122:1428-1444. [PMID: 36871159 PMCID: PMC10147835 DOI: 10.1016/j.bpj.2023.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/31/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
Understanding how cells remember previous mechanical environments to influence their fate, or mechanical memory, informs the design of biomaterials and therapies in medicine. Current regeneration therapies, such as cartilage regeneration procedures, require 2D cell expansion processes to achieve large cell populations critical for the repair of damaged tissues. However, the limit of mechanical priming for cartilage regeneration procedures before inducing long-term mechanical memory following expansion processes is unknown, and mechanisms defining how physical environments influence the therapeutic potential of cells remain poorly understood. Here, we identify a threshold to mechanical priming separating reversible and irreversible effects of mechanical memory. After 16 population doublings in 2D culture, expression levels of tissue-identifying genes in primary cartilage cells (chondrocytes) are not recovered when transferred to 3D hydrogels, while expression levels of these genes were recovered for cells only expanded for eight population doublings. Additionally, we show that the loss and recovery of the chondrocyte phenotype correlates with a change in chromatin architecture, as shown by structural remodeling of the trimethylation of H3K9. Efforts to disrupt the chromatin architecture by suppressing or increasing levels of H3K9me3 reveal that only with increased levels of H3K9me3 did the chromatin architecture of the native chondrocyte phenotype partially return, along with increased levels of chondrogenic gene expression. These results further support the connection between the chondrocyte phenotype and chromatin architecture, and also reveal the therapeutic potential of inhibitors of epigenetic modifiers as disruptors of mechanical memory when large numbers of phenotypically suitable cells are required for regeneration procedures.
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Affiliation(s)
- Adrienne K Scott
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado
| | - Eduard Casas
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, Colorado
| | - Stephanie E Schneider
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado
| | - Alison R Swearingen
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, Colorado
| | - Courtney L Van Den Elzen
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado
| | - Benjamin Seelbinder
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado
| | - Jeanne E Barthold
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado
| | - Jennifer F Kugel
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado
| | - Josh Lewis Stern
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado; Biochemistry and Molecular Genetics, O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Kyla J Foster
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado
| | - Nancy C Emery
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado
| | - Justin Brumbaugh
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, Colorado
| | - Corey P Neu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado; Biomedical Engineering Program, University of Colorado Boulder, Boulder, Colorado; BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado.
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Saphirstein RJ, Gao YZ, Lin QQ, Morgan KG. Cortical actin regulation modulates vascular contractility and compliance in veins. J Physiol 2015; 593:3929-41. [PMID: 26096914 DOI: 10.1113/jp270845] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 06/16/2015] [Indexed: 12/31/2022] Open
Abstract
Most cardiovascular research focuses on arterial mechanisms of disease, largely ignoring venous mechanisms. Here we examine ex vivo venous stiffness, spanning tissue to molecular levels, using biomechanics and magnetic microneedle technology, and show for the first time that venous stiffness is regulated by a molecular actin switch within the vascular smooth muscle cell in the wall of the vein. This switch connects the contractile apparatus within the cell to adhesion structures and facilitates stiffening of the vessel wall, regulating blood flow return to the heart. These studies also demonstrate that passive stiffness, the component of total stiffness not attributable to vascular smooth muscle activation, is severalfold lower in venous tissue than in arterial tissue. We show here that the activity of the smooth muscle cells plays a dominant role in determining total venous stiffness and regulating venous return. The literature on arterial mechanics is extensive, but far less is known about mechanisms controlling mechanical properties of veins. We use here a multi-scale approach to identify subcellular sources of venous stiffness. Portal vein tissue displays a severalfold decrease in passive stiffness compared to aortic tissues. The α-adrenergic agonist phenylephrine (PE) increased tissue stress and stiffness, both attenuated by cytochalasin D (CytoD) and PP2, inhibitors of actin polymerization and Src activity, respectively. We quantify, for the first time, cortical cellular stiffness in freshly isolated contractile vascular smooth muscle cells using magnetic microneedle technology. Cortical stiffness is significantly increased by PE and CytoD inhibits this increase but, surprisingly, PP2 does not. No detectable change in focal adhesion size, measured by immunofluorescence of FAK and zyxin, accompanies the PE-induced changes in cortical stiffness. Probing with phospho-specific antibodies confirmed activation of FAK/Src and ERK pathways and caldesmon phosphorylation. Thus, venous tissue stiffness is regulated both at the level of the smooth muscle cell cortex, via cortical actin polymerization, and by downstream smooth muscle effectors of Src/ERK signalling pathways. These findings identify novel potential molecular targets for the modulation of venous capacitance and venous return in health and disease.
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Affiliation(s)
| | - Yuan Z Gao
- Department of Health Sciences, Boston University, Boston, MA, USA.,Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Qian Qian Lin
- Department of Health Sciences, Boston University, Boston, MA, USA
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Bougault V, Blouin E, Turmel J, Boulet LP. Airway response to methacholine following eucapnic voluntary hyperpnea in athletes. PLoS One 2015; 10:e0121781. [PMID: 25789614 PMCID: PMC4366214 DOI: 10.1371/journal.pone.0121781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 02/09/2015] [Indexed: 11/18/2022] Open
Abstract
Aim To evaluate the changes in airway responsiveness to methacholine inhalation test (MIT) when performed after an eucapnic voluntary hyperpnea challenge (EVH) in athletes. Methods Two MIT preceded (visit 1) or not (visit 2) by an EVH, were performed in 28 athletes and 24 non-athletes. Twelve athletes and 13 non-athletes had airway hyperresponsiveness (AHR) to methacholine, and 11 athletes and 11 non-athletes had AHR to EVH (EVH+). Results The MIT PC20 post-EVH was significantly lower compared to baseline MIT PC20 by 1.3±0.7 doubling-concentrations in EVH+ athletes only (p<0.0001). No significant change was observed in EVH- athletes and EVH+/EVH- non-athletes. A significant correlation between the change in MIT PC20 post-EVH and EVH+/EVH- status and athlete/nonathlete status was found (Adjusted R2=0.26 and p<0.001). Three (11%) athletes and one (4%) non-athlete had a change in the diagnosis of AHR when MIT was performed consecutively to EVH. Conclusion The responsiveness to methacholine was increased by a previous indirect challenge in EVH+ athletes only. The mechanisms for such increase remain to be determined. MIT and EVH should ideally be performed on separate occasions as there is a small but possible risk to obtain a false-positive response to methacholine when performed immediately after the EVH. Trial Registration ClinicalTrials.gov NCT00686491
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Affiliation(s)
- Valérie Bougault
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- Université de Lille, EA4488 « Activité physique, muscle, santé », Lille, France
| | - Evelyne Blouin
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Julie Turmel
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
| | - Louis-Philippe Boulet
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC, Canada
- * E-mail:
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Djeddi D, Cantin D, Samson N, Praud JP. Nasal continuous positive airway pressure inhibits gastroesophageal reflux in newborn lambs. PLoS One 2014; 9:e107736. [PMID: 25226514 PMCID: PMC4167239 DOI: 10.1371/journal.pone.0107736] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 08/20/2014] [Indexed: 02/06/2023] Open
Abstract
Background Using esophageal pHmetry, nasal CPAP (nCPAP) has been shown to decrease acid gastroesophageal reflux (GER) in adult humans. Although both GER (mainly non-acid) and nCPAP use are very frequent in newborns, the effect of nCPAP on GER in early life is unknown. Having recently shown that the newborn lamb is a unique model for studying neonatal GER, our main objective was to assess the effect of nCPAP on GER in newborn lambs. Methods Eight newborn lambs, aged 2–3 days, were studied. Continuous esophageal pH-Impedance monitoring and polysomnography were performed for six hours during both spontaneous breathing and nCPAP application at 6 cmH2O (nCPAP6), in a randomized order. Results were compared in the two experimental conditions, as well as without CPAP during the following 6 hours. Results i) nCPAP6 virtually abolished GER [mean ±SD reflux number for 6 h = 9.1±8.6 without nCPAP6 vs. 0.6±1 with nCPAP6, P<0.05]; ii) GER number was also reduced during the 6 h-period following nCPAP6 application (18±16 without nCPAP6 vs. 7±8.1 with nCPAP6, P<0.05); iii) nCPAP6 decreased the depth and duration of lower esophageal sphincter relaxation. Conclusions nCPAP inhibits GER in the newborn lamb. Further clinical studies using different levels of nasal CPAP are needed to confirm this result in human infants.
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Affiliation(s)
- Djamal Djeddi
- Neonatal Respiratory Research Unit, Departments of Pediatrics and Physiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Pediatric Department, Amiens University Medical Center, Amiens, France
- * E-mail:
| | - Danny Cantin
- Neonatal Respiratory Research Unit, Departments of Pediatrics and Physiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Nathalie Samson
- Neonatal Respiratory Research Unit, Departments of Pediatrics and Physiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Jean-Paul Praud
- Neonatal Respiratory Research Unit, Departments of Pediatrics and Physiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Jensen MH, Watt J, Hodgkinson J, Gallant C, Appel S, El-Mezgueldi M, Angelini TE, Morgan KG, Lehman W, Moore JR. Effects of basic calponin on the flexural mechanics and stability of F-actin. Cytoskeleton (Hoboken) 2012; 69:49-58. [PMID: 22135101 PMCID: PMC3355516 DOI: 10.1002/cm.20548] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Revised: 10/28/2011] [Accepted: 11/14/2011] [Indexed: 01/12/2023]
Abstract
The cellular actin cytoskeleton plays a central role in the ability of cells to properly sense, propagate, and respond to external stresses and other mechanical stimuli. Calponin, an actin-binding protein found both in muscle and non-muscle cells, has been implicated in actin cytoskeletal organization and regulation. In this work, we studied the mechanical and structural interaction of actin with basic calponin, a differentiation marker in smooth muscle cells, on a single filament level. We imaged fluorescently labeled thermally fluctuating actin filaments and found that at moderate calponin binding densities, actin filaments were more flexible, evident as a reduction in persistence length from 8.0 to 5.8 μm. When calponin-decorated actin filaments were subjected to shear, we observed a marked reduction of filament lengths after decoration with calponin, which we argue was due to shear-induced filament rupture rather than depolymerization. This increased shear susceptibility was exacerbated with calponin concentration. Cryo-electron microscopy results confirmed previously published negative stain electron microscopy results and suggested alterations in actin involving actin subdomain 2. A weakening of F-actin intermolecular association is discussed as the underlying cause of the observed mechanical perturbations.
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Affiliation(s)
- Mikkel Herholdt Jensen
- Boston University, School of Medicine, Boston, MA
- Boston University, Department of Physics, Boston, MA
| | - James Watt
- Boston University, School of Medicine, Boston, MA
| | - Julie Hodgkinson
- Medical School Hannover, Department of Molecular and Cell Physiology, Hannover, Germany
| | - Cynthia Gallant
- Boston University, Department of Health Sciences, Boston, MA
| | - Sarah Appel
- Boston University, Department of Health Sciences, Boston, MA
| | | | - Thomas E. Angelini
- University of Florida, Department of Mechanical and Aerospace Engineering, Gainesville, FL
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Dowell ML, Lavoie TL, Lakser OJ, Dulin NO, Fredberg JJ, Gerthoffer WT, Seow CY, Mitchell RW, Solway J. MEK modulates force-fluctuation-induced relengthening of canine tracheal smooth muscle. Eur Respir J 2010; 36:630-7. [PMID: 20110395 DOI: 10.1183/09031936.00160209] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Tidal breathing, and especially deep breathing, is known to antagonise bronchoconstriction caused by airway smooth muscle (ASM) contraction; however, this bronchoprotective effect of breathing is impaired in asthma. Force fluctuations applied to contracted ASM in vitro cause it to relengthen, force-fluctuation-induced relengthening (FFIR). Given that breathing generates similar force fluctuations in ASM, FFIR represents a likely mechanism by which breathing antagonises bronchoconstriction. Thus it is of considerable interest to understand what modulates FFIR, and how ASM might be manipulated to exploit this phenomenon. It was demonstrated previously that p38 mitogen-activated protein kinase (MAPK) signalling regulates FFIR in ASM strips. Here, it was hypothesised that the MAPK kinase (MEK) signalling pathway also modulates FFIR. In order to test this hypothesis, changes in FFIR were measured in ASM treated with the MEK inhibitor, U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene). Increasing concentrations of U0126 caused greater FFIR. U0126 reduced extracellular signal-regulated kinase 1/2 phosphorylation without affecting isotonic shortening or 20-kDa myosin light chain and p38 MAPK phosphorylation. However, increasing concentrations of U0126 progressively blunted phosphorylation of high-molecular-weight caldesmon (h-caldesmon), a downstream target of MEK. Thus changes in FFIR exhibited significant negative correlation with h-caldesmon phosphorylation. The present data demonstrate that FFIR is regulated through MEK signalling, and suggest that the role of MEK is mediated, in part, through caldesmon.
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Affiliation(s)
- M L Dowell
- Section of Pulmonary Medicine, Dept of Pediatrics, The University of Chicago, 5841 S. Maryland Avenue, MC4064, Chicago, IL 60637, USA.
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Greenberg MJ, Wang CLA, Lehman W, Moore JR. Modulation of actin mechanics by caldesmon and tropomyosin. ACTA ACUST UNITED AC 2008; 65:156-64. [PMID: 18000881 DOI: 10.1002/cm.20251] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The ability of cells to sense and respond to physiological forces relies on the actin cytoskeleton, a dynamic structure that can directly convert forces into biochemical signals. Because of the association of muscle actin-binding proteins (ABPs) may affect F-actin and hence cytoskeleton mechanics, we investigated the effects of several ABPs on the mechanical properties of the actin filaments. The structural interactions between ABPs and helical actin filaments can vary between interstrand interactions that bridge azimuthally adjacent actin monomers between filament strands (i.e. by molecular stapling as proposed for caldesmon) or, intrastrand interactions that reinforce axially adjacent actin monomers along strands (i.e. as in the interaction of tropomyosin with actin). Here, we analyzed thermally driven fluctuations in actin's shape to measure the flexural rigidity of actin filaments with different ABPs bound. We show that the binding of phalloidin increases the persistence length of actin by 1.9-fold. Similarly, the intrastrand reinforcement by smooth and skeletal muscle tropomyosins increases the persistence length 1.5- and 2- fold respectively. We also show that the interstrand crosslinking by the C-terminal actin-binding fragment of caldesmon, H32K, increases persistence length by 1.6-fold. While still remaining bound to actin, phosphorylation of H32K by ERK abolishes the molecular staple (Foster et al. 2004. J Biol Chem 279;53387-53394) and reduces filament rigidity to that of actin with no ABPs bound. Lastly, we show that the effect of binding both smooth muscle tropomyosin and H32K is not additive. The combination of structural and mechanical studies on ABP-actin interactions will help provide information about the biophysical mechanism of force transduction in cells.
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Affiliation(s)
- M J Greenberg
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Wu X, Morgan KG, Jones CJ, Tribe RM, Taggart MJ. Myometrial mechanoadaptation during pregnancy: implications for smooth muscle plasticity and remodelling. J Cell Mol Med 2008; 12:1360-73. [PMID: 18363833 PMCID: PMC2729593 DOI: 10.1111/j.1582-4934.2008.00306.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The smooth muscle of the uterus during pregnancy presents a unique circumstance of physiological mechanotransduction as the tissue remodels in response to stretches imposed by the growing foetus(es), yet the nature of the molecular and functional adaptations remain unresolved. We studied, in myometrium isolated from non-pregnant (NP) and pregnant mice, the active and passive length–tension curves by myography and the expression and activation by immunoblotting of focal adhesion-related proteins known in other systems to participate in mechanosensing and mechanotransduction. In situ uterine mass correlated with pup number and weight throughout pregnancy. In vitro myometrial active, and passive, length-tension curves shifted significantly to the right during pregnancy indicative of altered mechanosensitivity; at term, maximum active tension was generated following 3.94 ± 0.33-fold stretch beyond slack length compared to 1.91 ± 0.12-fold for NP mice. Moreover, mechanotransduction was altered during pregnancy as evidenced by the progressive increase in absolute force production at each optimal stretch. Pregnancy was concomitantly associated with an increased expression of the dense plaque-associated proteins FAK and paxillin, and elevated activation of FAK, paxillin, c-Src and extracellular signal-regulated kinase (ERK1/2) which reversed 1 day post-partum. Electron microscopy revealed close appositioning of neighbouring myometrial cells across a narrow extracellular cleft adjoining plasmalemmal dense plaques. Collectively, these results suggest a physiological basis of myometrial length adaptation, long known to be a property of many smooth muscles, whereupon plasmalemmal dense plaque proteins serve as molecular signalling and structural platforms contributing to functional (contractile) remodelling in response to chronic stretch.
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Affiliation(s)
- X Wu
- School of Clinical & Laboratory Sciences, University of Manchester, Great Britain
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