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Nordquist EM, Dutta P, Kodigepalli KM, Mattern C, McDermott MR, Trask AJ, LaHaye S, Lindner V, Lincoln J. Tgfβ1-Cthrc1 Signaling Plays an Important Role in the Short-Term Reparative Response to Heart Valve Endothelial Injury. Arterioscler Thromb Vasc Biol 2021; 41:2923-2942. [PMID: 34645278 PMCID: PMC8612994 DOI: 10.1161/atvbaha.121.316450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Aortic valve disease is a common worldwide health burden with limited treatment options. Studies have shown that the valve endothelium is critical for structure-function relationships, and disease is associated with its dysfunction, damage, or injury. Therefore, therapeutic targets to maintain a healthy endothelium or repair damaged endothelial cells could hold promise. In this current study, we utilize a surgical mouse model of heart valve endothelial cell injury to study the short-term response at molecular and cellular levels. The goal is to determine if the native heart valve exhibits a reparative response to injury and identify the mechanisms underlying this process. Approach and Results: Mild aortic valve endothelial injury and abrogated function was evoked by inserting a guidewire down the carotid artery of young (3 months) and aging (16-18 months) wild-type mice. Short-term cellular responses were examined at 6 hours, 48 hours, and 4 weeks following injury, whereas molecular profiles were determined after 48 hours by RNA-sequencing. Within 48 hours following endothelial injury, young wild-type mice restore endothelial barrier function in association with increased cell proliferation, and upregulation of transforming growth factor beta 1 (Tgfβ1) and the glycoprotein, collagen triple helix repeat containing 1 (Cthrc1). Interestingly, this beneficial response to injury was not observed in aging mice with known underlying endothelial dysfunction. CONCLUSIONS Data from this study suggests that the healthy valve has the capacity to respond to mild endothelial injury, which in short term has beneficial effects on restoring endothelial barrier function through acute activation of the Tgfβ1-Cthrc1 signaling axis and cell proliferation.
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Affiliation(s)
- Emily M. Nordquist
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Punashi Dutta
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Karthik M. Kodigepalli
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Carol Mattern
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
| | - Michael R. McDermott
- Center for Cardiovascular Research, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
- The Heart Center, Nationwide Children’s Hospital, Columbus, Ohio, USA
| | - Aaron J. Trask
- Center for Cardiovascular Research, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
- The Heart Center, Nationwide Children’s Hospital, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Stephanie LaHaye
- The Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
| | - Volkhard Lindner
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, USA
| | - Joy Lincoln
- Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- The Herma Heart Institute, Children’s Wisconsin, Milwaukee, WI, USA
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Driscoll K, Cruz AD, Butcher JT. Inflammatory and Biomechanical Drivers of Endothelial-Interstitial Interactions in Calcific Aortic Valve Disease. Circ Res 2021; 128:1344-1370. [PMID: 33914601 DOI: 10.1161/circresaha.121.318011] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Calcific aortic valve disease is dramatically increasing in global burden, yet no therapy exists outside of prosthetic replacement. The increasing proportion of younger and more active patients mandates alternative therapies. Studies suggest a window of opportunity for biologically based diagnostics and therapeutics to alleviate or delay calcific aortic valve disease progression. Advancement, however, has been hampered by limited understanding of the complex mechanisms driving calcific aortic valve disease initiation and progression towards clinically relevant interventions.
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Affiliation(s)
| | - Alexander D Cruz
- Meinig School of Biomedical Engineering, Cornell University, Ithaca NY
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3
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Adesanya TMA, Russell M, Park KH, Zhou X, Sermersheim MA, Gumpper K, Koenig SN, Tan T, Whitson BA, Janssen PML, Lincoln J, Zhu H, Ma J. MG 53 Protein Protects Aortic Valve Interstitial Cells From Membrane Injury and Fibrocalcific Remodeling. J Am Heart Assoc 2020; 8:e009960. [PMID: 30741589 PMCID: PMC6405656 DOI: 10.1161/jaha.118.009960] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background The aortic valve of the heart experiences constant mechanical stress under physiological conditions. Maladaptive valve injury responses contribute to the development of valvular heart disease. Here, we test the hypothesis that MG 53 (mitsugumin 53), an essential cell membrane repair protein, can protect valvular cells from injury and fibrocalcific remodeling processes associated with valvular heart disease. Methods and Results We found that MG 53 is expressed in pig and human patient aortic valves and observed aortic valve disease in aged Mg53-/- mice. Aortic valves of Mg53-/- mice showed compromised cell membrane integrity. In vitro studies demonstrated that recombinant human MG 53 protein protects primary valve interstitial cells from mechanical injury and that, in addition to mediating membrane repair, recombinant human MG 53 can enter valve interstitial cells and suppress transforming growth factor-β-dependent activation of fibrocalcific signaling. Conclusions Together, our data characterize valve interstitial cell membrane repair as a novel mechanism of protection against valvular remodeling and assess potential in vivo roles of MG 53 in preventing valvular heart disease.
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Affiliation(s)
- T M Ayodele Adesanya
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Melanie Russell
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Ki Ho Park
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Xinyu Zhou
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | | | - Kristyn Gumpper
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Sara N Koenig
- 2 Department of Physiology and Cell Biology The Ohio State University Wexner Medical Center Columbus OH
| | - Tao Tan
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Bryan A Whitson
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Paul M L Janssen
- 2 Department of Physiology and Cell Biology The Ohio State University Wexner Medical Center Columbus OH
| | - Joy Lincoln
- 3 Center for Cardiovascular Research The Research Institute at Nationwide Children's Hospital Columbus OH
| | - Hua Zhu
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Jianjie Ma
- 1 Department of Surgery The Ohio State University Wexner Medical Center Columbus OH
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4
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Li C, Xu S, Gotlieb AI. The progression of calcific aortic valve disease through injury, cell dysfunction, and disruptive biologic and physical force feedback loops. Cardiovasc Pathol 2013; 22:1-8. [DOI: 10.1016/j.carpath.2012.06.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/01/2012] [Accepted: 06/04/2012] [Indexed: 10/28/2022] Open
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5
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Hajdu Z, Romeo SJ, Fleming PA, Markwald RR, Visconti RP, Drake CJ. Recruitment of bone marrow-derived valve interstitial cells is a normal homeostatic process. J Mol Cell Cardiol 2011; 51:955-65. [PMID: 21871458 DOI: 10.1016/j.yjmcc.2011.08.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/12/2011] [Accepted: 08/09/2011] [Indexed: 01/09/2023]
Abstract
Advances in understanding of the maintenance of the cardiac valves during normal cardiac function and response to injury have led to several novel findings, including that there is contribution of extra-cardiac cells to the major cellular population of the valve: the valve interstitial cell (VIC). While suggested to occur in human heart studies, we have been able to experimentally demonstrate, using a mouse model, that cells of bone marrow hematopoietic stem cell origin engraft into the valves and synthesize collagen type I. Based on these initial findings, we sought to further characterize this cell population in terms of its similarity to VICs and begin to elucidate its contribution to valve homeostasis. To accomplish this, chimeric mice whose bone marrow was repopulated with enhanced green fluorescent protein (EGFP) expressing total nucleated bone marrow cells were used to establish a profile of EGFP(+) valve cells in terms of their expression of hematopoietic antigens, progenitor markers, fibroblast- and myofibroblast-related molecules, as well as their distribution within the valves. Using this profile, we show that normal (non-irradiated, non-transplanted) mice have BM-derived cell populations that exhibit identical morphology and phenotype to those observed in transplanted mice. Collectively, our findings establish that the engraftment of bone marrow-derived cells occurs as part of normal valve homeostasis. Further, our efforts demonstrate that the use of myeloablative irradiation, which is commonly employed in studies involving bone marrow transplantation, does not elicit changes in the bone marrow-derived VIC phenotype in recipient mice.
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Affiliation(s)
- Zoltan Hajdu
- Department of Regenerative Medicine and Cell Biology Medical University of South Carolina, Charleston, SC 29425, USA
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6
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The response to valve injury. A paradigm to understand the pathogenesis of heart valve disease. Cardiovasc Pathol 2011; 20:183-90. [DOI: 10.1016/j.carpath.2010.09.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 08/23/2010] [Accepted: 09/09/2010] [Indexed: 12/21/2022] Open
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7
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Xu S, Liu AC, Kim H, Gotlieb AI. Cell density regulates in vitro activation of heart valve interstitial cells. Cardiovasc Pathol 2011; 21:65-73. [PMID: 21397521 DOI: 10.1016/j.carpath.2011.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Revised: 10/30/2010] [Accepted: 01/26/2011] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Valve interstitial cells, the most prominent cell type in the heart valve, are activated and express α-smooth muscle actin in valve repair and in diseased valves. We hypothesize that cell density, time in culture, and the establishment of cell-cell contacts may be involved in regulating valve interstitial cell activation in vitro. METHODS To study cell density, valve interstitial cells were plated at passages 3 to 5, at a density of 17,000 cells/22 × 22 mm(2) coverslip, and grown for 1, 2, 4, 7, and 10 days. Valve interstitial cells were stained for α-smooth muscle actin and viewed under confocal microscopy to characterize the intensity of staining. To study time in culture, valve interstitial cells were plated at a 10-fold higher density to achieve similar growth densities over a shorter time period compared with valve interstitial cells plated at low density. α-Smooth muscle actin staining was compared at the same time points between those plated at high and low densities. To confirm valve interstitial cell activation as indicated by α-smooth muscle actin staining, valve interstitial cells were stained for cofilin at days 2, 5, 8, and 14 days postplating. To study the association of transforming growth factor β with valve interstitial cell activation with respect to cell density, valve interstitial cells were stained for α-smooth muscle actin and transforming growth factor β at 2, 4, 6, and 8 days postplating. To study the activation of the transforming growth factor β signaling pathway, valve interstitial cells were stained for pSmad2/3 at days 2, 4, 6, 8, 10, and 12 days postplating. To study cell contacts and activation, subconfluent and confluent cultures of valve interstitial cells were stained for β-catenin, N-cadherin, and α-smooth muscle actin. Also, whole-cell lysates of subconfluent and confluent valve interstitial cell cultures were probed by Western blot analysis for phospho-β-catenin at Ser33/37/Thr41, which is the form of β-catenin targeted for proteosomal degradation. RESULTS The percentage valve interstitial cells with high-intensity α-smooth muscle actin staining decreases significantly between days 1 and 4, and at confluency, most cells show absent or low-intensity staining, regardless of time in culture. Similar results are obtained with cofilin staining. Transforming growth factor β and nuclear pSmad2/3 staining in valve interstitial cells decreases concurrently with valve interstitial cell activation as cell density increases. Examining β-catenin and N-cadherin staining, single valve interstitial cells show no cell-cell contact with strong cytoplasmic staining, with some showing nuclear staining of β-catenin, while confluent monolayers show strong staining of fully established cell-cell contacts, weak cytoplasmic staining, and absent nuclear staining. The presence of cell-cell contacts is associated with a decreased α-smooth muscle actin. The level of phospho-β-catenin at Ser33/37/Thr41 is lower in confluent cultures compared with low-density subconfluent valve interstitial cell cultures. CONCLUSION Cell-cell contacts may inhibit valve interstitial cell activation, while absence of cell-cell contacts may contribute to activation.
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Affiliation(s)
- Songyi Xu
- Department of Pathology, Toronto General Research Institute, University Health Network, Ontario, Canada
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8
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Schwartz RS, Holmes DR, Van Tassel RA, Hauser R, Henry TD, Mooney M, Matthews R, Doshi S, Jones RM, Virmani R. Left atrial appendage obliteration: mechanisms of healing and intracardiac integration. JACC Cardiovasc Interv 2010; 3:870-7. [PMID: 20723861 DOI: 10.1016/j.jcin.2010.04.017] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 03/26/2010] [Accepted: 04/26/2010] [Indexed: 02/08/2023]
Abstract
OBJECTIVES The objectives of this study were: 1) to delineate the temporal course of histopathologic healing as the left atrial appendage (LAA) is obliterated by a mechanical device; and 2) to compare this process with other intravascular and intracardiac implanted technologies. BACKGROUND Intracardiac device healing is incompletely understood. We thus studied the histopathology of device-based LAA obliteration. METHODS Nine dog hearts were examined over time after LAA device placement and results were compared with human hearts with prior LAA obliteration using the same device. RESULTS At 3 days in dogs, atrial surfaces were covered by fibrin, which sealed gaps between the LA wall and the device and filled the LA appendage cavity. At 45 days, endothelial cells covered the endocardial surface with underlying smooth muscle cells that sealed the device-LA interface. Regions with prior thrombus were replaced by endocardium surrounding the device membrane. Disorganized thrombus remained in the LAA body and at the periphery near the appendage walls. Mild inflammation was observed as thrombus resorbed. By 90 days, a complete endocardial lining covered the former LAA ostium. Organizing thrombus had become connective tissue, with no residual inflammation. The human necropsy hearts had similar findings. In these 4 hearts (139, 200, 480, and 852 days after implant), the ostial fabric membrane was covered with endocardium. The appendage surface contained organizing thrombus with minimal inflammation. Organizing fibrous tissue was inside the LAA cavity, prominent near the atrial wall. The LAA interior contained organizing thrombus. CONCLUSIONS This intracardiac device integration study delineated healing stages of early thrombus deposition, thrombus organization, inflammation and granulation tissue, final healing by connective tissue, and endocardialization without inflammation. These observations may yield insight into cellular healing processes in other cardiac devices.
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Affiliation(s)
- Robert S Schwartz
- Minneapolis Heart Institute and Foundation, Minneapolis, Minnesota 55407, USA.
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9
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Design and validation of a novel splashing bioreactor system for use in mitral valve organ culture. Ann Biomed Eng 2010; 38:3280-94. [PMID: 20661646 DOI: 10.1007/s10439-010-0129-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Accepted: 07/12/2010] [Indexed: 10/19/2022]
Abstract
Previous research in our lab suggested that heart valve tissues cultured without mechanical stimulation do not retain their in vivo microstructure, i.e., cell density decreased within the deep tissue layers and increased at the periphery. In this study, a splashing rotating bioreactor was designed to apply mechanical stimulation to a mitral valve leaflet segment. Porcine valve segments (n = 9-10 per group) were cultured in the bioreactor for 2 weeks (dynamic culture), negative controls were cultured without mechanical stimulation (static culture), and baseline controls were fresh uncultured samples. Overall changes in cellularity and extracellular matrix (ECM) structure were assessed by H&E and Movat pentachrome stains. Tissues were also immunostained for multiple ECM components and turnover mediators. After 2 weeks of culture, proliferating cells were distributed throughout the tissue in segments cultured in the bioreactor, in contrast to segments cultured without mechanical stimulation. Most ECM components, especially collagen types I and III, better maintained normal expression patterns and magnitudes (as found in baseline controls) over 2 weeks of dynamic organ culture compared to static culture. Lack of mechanical stimulation changed several aspects of the tissue microstructure, including the cell distribution and ECM locations. In conclusion, mechanical stimulation by the bioreactor maintained tissue integrity, which will enable future in vitro investigation of mitral valve remodeling.
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Liu AC, Gotlieb AI. Transforming growth factor-beta regulates in vitro heart valve repair by activated valve interstitial cells. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:1275-85. [PMID: 18832581 DOI: 10.2353/ajpath.2008.080365] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The regulation of valve interstitial cell (VIC) function in response to tissue injury and valve disease is not well understood. Because transforming growth factor-beta (TGF-beta) has been implicated in tissue repair, we tested the hypothesis that TGF-beta is a regulator of VIC activation and associated cell responses that occur during early repair processes. We used a well-characterized wound model that was created by mechanical denudation of a confluent VIC monolayer to study activation and repair 24 hours after wounding. VIC activation was demonstrated by immunofluorescent localization of alpha-smooth muscle actin (alpha-SMA), and alpha-SMA mRNA levels were quantified by real-time polymerase chain reaction. Proliferation and apoptosis were quantified by bromodeoxyuridine staining and terminal deoxynucleotidyl transferase dUTP nick end labeling, respectively. Repair was quantified by measuring VIC extension into the wound, and TGF-beta expression was shown by immunofluorescent localization of intracellular TGF-beta. Compared with nonwounded monolayers, VICs at the wound edge showed alpha-SMA staining, increased alpha-SMA mRNA content, elongation into the wound with stress fibers, proliferation, and apoptosis. VICs at the wound edge also showed increased TGF-beta and pSmad2/3 staining with co-expression of alpha-SMA. Addition of TGF-beta neutralizing antibody to the wound decreased VIC activation, alpha-SMA mRNA content, proliferation, apoptosis, wound closure rate, and stress fibers. Conversely, exogenous addition of TGF-beta to the wound increased VIC activation, proliferation, wound closure rate, and stress fibers. Thus, wounding activates VICs, and TGF-beta signaling modulates VIC response to injury.
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Affiliation(s)
- Amber C Liu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
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11
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Pho M, Lee W, Watt DR, Laschinger C, Simmons CA, McCulloch CA. Cofilin is a marker of myofibroblast differentiation in cells from porcine aortic cardiac valves. Am J Physiol Heart Circ Physiol 2008; 294:H1767-78. [DOI: 10.1152/ajpheart.01305.2007] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The formation of myofibroblasts in valve interstitial cell (VIC) populations contributes to fibrotic valvular disease. We examined myofibroblast differentiation in VICs from porcine aortic valves. In normal valves, cells immunostained for α-smooth muscle actin (α-SMA, a myofibroblast marker) were rare (0.69 ± 0.48%), but in sclerotic valves of animals fed an atherogenic diet, myofibroblasts were spatially clustered and abundant (31.2 ± 6.3%). In cultured VIC populations from normal valves, SMA-positive myofibroblasts were also spatially clustered, abundant (21% positive cells after 1 passage), and stained for collagen type I and vimentin but not desmin. For an analysis of stem cells, two-color flow cytometry of isolated cells stained with Hoechst 33342 demonstrated that 0.5% of VICs were side population cells; none stained for SMA. Upon culture, sorted side population cells generated ∼85% SMA-positive cells, indicating that some myofibroblasts originate from a rare population with stem cell characteristics. Plating cells on rigid collagen substrates enabled the formation of myofibroblasts after 5 days in culture, which was completely blocked by culture of cells on compliant collagen substrates. Exogenous tensile force also significantly increased SMA expression in VICs. Isotope-coded affinity tags and mass spectrometry were used to identify differentially expressed proteins in myofibroblast differentiation of VICs. Of the nine proteins that were identified, cofilin expression and phospho-cofilin were strongly increased by conditions favoring myofibroblast differentiation. Knockdown of cofilin with small-interfering RNA inhibited collagen gel contraction and reduced myofibroblast differentiation as assessed by the SMA incorporation into stress fibers. When compared with normal valves, diseased valves showed strong immunostaining for cofilin that colocalized with SMA in clustered cells. We conclude that in VICs, cofilin is a marker for myofibroblasts in vivo and in vitro that arise from a rare population of stem cells and require a rigid matrix for formation.
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Liang W, McDonald P, McManus B, van Breemen C, Wang X. P2Y2 Receptor-Mediated Ca2+ Signaling and Spontaneous Ca2+ Releases in Human Valvular Myofibroblasts. Int Heart J 2008; 49:221-36. [DOI: 10.1536/ihj.49.221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Willmann Liang
- School of Biological Sciences, Nanyang Technological University
| | - Paul McDonald
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
| | - Bruce McManus
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
| | - Cornelis van Breemen
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
| | - Xiaodong Wang
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia
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Liu AC, Joag VR, Gotlieb AI. The emerging role of valve interstitial cell phenotypes in regulating heart valve pathobiology. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:1407-18. [PMID: 17823281 PMCID: PMC2043503 DOI: 10.2353/ajpath.2007.070251] [Citation(s) in RCA: 435] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The study of the cellular and molecular pathogenesis of heart valve disease is an emerging area of research made possible by the availability of cultures of valve interstitial cells (VICs) and valve endothelial cells (VECs) and by the design and use of in vitro and in vivo experimental systems that model elements of valve biological and pathobiological activity. VICs are the most common cells in the valve and are distinct from other mesenchymal cell types in other organs. We present a conceptual approach to the investigation of VICs by focusing on VIC phenotype-function relationships. Our review suggests that there are five identifiable phenotypes of VICs that define the current understanding of their cellular and molecular functions. These include embryonic progenitor endothelial/mesenchymal cells, quiescent VICs (qVICs), activated VICs (aVICs), progenitor VICs (pVICs), and osteoblastic VICs (obVICs). Although these may exhibit plasticity and may convert from one form to another, compartmentalizing VIC function into distinct phenotypes is useful in bringing clarity to our understanding of VIC pathobiology. We present a conceptual model that is useful in the design and interpretation of studies on the function of an important phenotype in disease, the activated VIC. We hope this review will inspire members of the investigative pathology community to consider valve pathobiology as an exciting new frontier exploring pathogenesis and discovering new therapeutic targets in cardiovascular diseases.
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Affiliation(s)
- Amber C Liu
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, M5G 1L5, ON, Canada
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14
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Durbin A, Nadir NA, Rosenthal A, Gotlieb AI. Nitric oxide promotes in vitro interstitial cell heart valve repair. Cardiovasc Pathol 2005; 14:12-8. [PMID: 15710286 DOI: 10.1016/j.carpath.2004.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 10/21/2004] [Accepted: 11/11/2004] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The cell and molecular biology of heart valve wound repair is not well understood. Valve interstitial cells (IC) are thought to play an important role in valvular wound repair. Because nitric oxide (NO) has been implicated in wound repair, we tested the hypothesis that NO promotes valvular wound repair by examining the presence of the inducible form of nitric oxide synthase (iNOS) in wounded IC monolayers, in vitro. METHODS Linear denuding wounds were made in confluent monolayers of porcine mitral valve IC plated on glass coverslips. Cultures were fixed at various times (0 to 48 h postwounding), and iNOS was localized in the cells by immunofluorescence microscopy. Cultures were also incubated with iNOS inhibitors L-N(G)-nitroarginine methyl ester (L-NAME) and N-(3-(Aminomethyl)benzyl)acetamidine (1400W), and the extent of wound closure with and without inhibitor was measured at 24, 48 and 72 h postwounding. RESULTS From 6 to 24 h postwounding, iNOS localization was increased at the wound edge. At 48 h, iNOS was localized beyond the wound edge, into the monolayer, where the intensity of the signal gradually diminished until it was virtually imperceptible. At 24 and 48 h, the inhibition of iNOS with both L-NAME and 1400W resulted in a significant delay in wound closure. CONCLUSION NO promotes valve wound repair through an effect on IC migration.
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Affiliation(s)
- Adam Durbin
- Toronto General Research Institute, Toronto, ON, Canada
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15
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Gotlieb AI, Rosenthal A, Kazemian P. Fibroblast growth factor 2 regulation of mitral valve interstitial cell repair in vitro. J Thorac Cardiovasc Surg 2002; 124:591-7. [PMID: 12202876 DOI: 10.1067/mtc.2002.123812] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Because elongated mitral valve interstitial cells have features of myofibroblasts, it is likely that these cells are essential for the repair of injured valve leaflets. We characterized the cellular morphology and pattern of repair of these interstitial cells in wounds produced in vitro and tested the hypothesis that fibroblast growth factor 2 enhances interstitial cell repair. METHODS Mitral valve interstitial cells were plated onto glass coverslips, reached confluence after 1 week, and were wounded by passage of a spatula along the center of a monolayer, which created a linear wound with two edges. The wounds were observed from 0 to 96 hours by phase-contrast microscopy. Wounds were also fixed at 0, 2, and 24 hours and stained for fibroblast growth factor 2 and fibroblast growth factor receptor 1 by means of immunofluorescence and laser confocal microscopy. RESULTS Cells in confluent monolayers and in the monolayer behind the wound edge formed a multilayered orthogonal pattern of elongated cells similar to fibroblasts. Cells along the wound edge migrated into the wound after 4 hours, and at 24 hours single cells with prominent lamellipodia and tails were present within the wound. There was overlapping of cells as well, similar to smooth muscle cells. Fibroblast growth factor 2 and fibroblast growth factor receptor 1 were present in the cells of the undisturbed confluent monolayer. They were upwardly regulated relative to the unwounded monolayer in the cells along the wound edge at 2 hours and in the monolayer behind the wound edge at 24 hours. In single cells that migrated into the wound, fibroblast growth factor 2 and fibroblast growth factor receptor 1 were prominent. Fibroblast growth factor 2 showed a 6-fold increase in concentration relative to unwounded cultures in conditioned medium from wounded cultures at 2 hours after wounding. Addition of a neutralizing antibody to fibroblast growth factor 2 significantly delayed wound closure at 24 to 96 hours. Addition of exogenous fibroblast growth factor 2 to cultures at the time of wounding did not enhance wound repair. CONCLUSION Mitral valve interstitial cells have the ability to repair wounds, and fibroblast growth factor 2 is a modulator of these repair processes.
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Affiliation(s)
- Avrum I Gotlieb
- Vascular Research Laboratory, Toronto General Hospital, University Health Network, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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McDonald PC, Wilson JE, McNeill S, Gao M, Spinelli JJ, Rosenberg F, Wiebe H, McManus BM. The challenge of defining normality for human mitral and aortic valves: geometrical and compositional analysis. Cardiovasc Pathol 2002; 11:193-209. [PMID: 12140125 DOI: 10.1016/s1054-8807(01)00102-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Advances in digital imaging technology and in tools for obtaining detailed quantitation of morphological features have facilitated a new approach to pathological assessment of many tissues, including heart valves. In the present study, we quantitatively examined the tissue geometry and composition of structurally normal mitral and aortic valves removed at autopsy or surgery from patients aged 15-84 years. Through univariate analyses of quantitative variables, we have determined which features change distinctively with age. The anterior mitral valve leaflet (AMV) underwent a statistically significant decrease in area of the valve proper and an increase in the number of superficial tissue accumulations called onlays as the patients aged. For all geometric variables measured in the aortic valve, increases were seen with age, leading to a thicker valve, with enlargement of the valve proper and onlays, and with changes in the number of onlays. The mitral valve proper, composed largely of collagen in younger individuals, showed significant increases in glycosaminoglycans and elastin and a relative decrease in collagen with age. The compositional characteristics of the aortic valve proper were similar to those of the mitral valve, with a dramatic relative increase in elastin and a decrease in collagen with age. Valve onlays, when present, were similar in composition to the valve proper for both valves. Our findings regarding normal valve tissue composition, when taken in the context of geometrical features, and together with evidence of age-related changes in the relative amounts of specific constituents, provide a basis on which to analyze human heart valves affected by various known or putative diseases.
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Affiliation(s)
- Paul C McDonald
- UBC McDonald Research Laboratories/The iCAPTUR(4)E Center, Department of Pathology and Laboratory Medicine, St. Paul's Hospital/Providence Health Care, University of British Columbia, Room 292, 1081 Burrard Street, Vancouver, BC, Canada, V6Z 1Y6
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Abstract
BACKGROUND Composed of endocardial endothelial, valvular interstitial, cardiac muscle, and smooth muscle cells (SMC), heart valves are prone to various pathologic conditions the morphology of which has been well described. The morphology of diseased valves suggest that the "response to injury" process occurs in these valves, and is associated with an accumulation of interstitial cells and matrix, valvular inflammation and calcification, conditions that lead to dysfunction. The purpose of this study is to describe the current knowledge of the regulation of the valvular "response to injury" process, since we feel that this paradigm is essential to understanding valve disease. METHODS The pertinent literature relating to the cell and molecular biology of valvular repair, and specifically interstitial cell function in valve repair, is reviewed. RESULTS The cell and molecular biology of valve interstitial cells are poorly understood. Molecules regulating some of the aspects of the "response to injury" process have been studied, however, the signal transduction pathways, gene activation, and interactions of bioactive molecules with each other, with cells, and with the matrix have not been characterized. Initial studies identify the cell and molecular biology of interstitial cells to be an important area of research. Agents that have been studied include nitric oxide (NO) and FGF-2 and several matrix-related proteins including osteopontin. The present review suggests several directions for future study and a working model of valvular repair is presented. DISCUSSION The regulation of the "response to injury" process in the human heart valve is still largely unknown. The cell and molecular events and processes that occur in heart valve function and repair remain poorly understood. These events and processes are vital to our understanding of the pathobiology of heart valve disease, and to the successful design of tissue engineered replacement valves.
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Affiliation(s)
- Adam D Durbin
- Toronto General Research Institute, Toronto, Ontario, Canada
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Lester WM, Damji AA, Gedeon I, Tanaka M. Interstitial cells from the atrial and ventricular sides of the bovine mitral valve respond differently to denuding endocardial injury. IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY : JOURNAL OF THE TISSUE CULTURE ASSOCIATION 1993; 29A:41-50. [PMID: 8095255 DOI: 10.1007/bf02634370] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The mitral valve has atrial and ventricular sides, each lined by endocardial cells. The valve stroma contains alpha smooth muscle actin positive interstitial cells, collagen, glycosaminoglycans, and elastic tissue. To eliminate the effect of endocardium on wound repair in bovine mitral valve organ culture, the endocardium was removed from both sides of the valve. At 6 days, organ cultures of these preparations revealed surface cells on the ventricular side but not in the atrial side. Ventricular surface cells were negative for Factor VIII-related antigen, and positive for alpha smooth muscle actin. Immunoperoxidase staining for proliferating cell nuclear antigen/cyclin, a marker for cell proliferation, revealed a positive labeling index of (mean +/- standard deviation) 0.08 +/- 0.16% for interstitial cells from the atrial side and 0.14 +/- 0.19% for ventricular side interstitial cells in uncultured preparations (not significant), and 0.44 +/- 0.69% for atrial side interstitial cells and 2.25 +/- 1.64% for ventricular side interstitial cells in the cultured preparations (significant, P < 0.0006). The results suggest that in organ culture, interstitial cells from the ventricular side of the mitral valve respond to a denuding endocardial injury by proliferating and migrating onto the adjacent surface whereas interstitial cells from the atrial side do not. This difference in the response to injury of interstitial cells from the atrial and ventricular sides of the valve may reflect differences in phenotype or may be due to effects of extracellular matrix on interstitial cell behavior. The latter is possible because of differences in the extracellular matrix of the atrial and ventricular sides of the valve.
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Affiliation(s)
- W M Lester
- Department of Pathology, University of Calgary, Alberta, Canada
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