title: Relationships between melanocytes, mechanical properties and extracellular matrix composition in mouse heart valves.
abstract: Heart valves are complex structures composed of organized layers of extracellular matrix, and interstitial and overlying endothelial cells. In this article, we present the specific localization of a population of melanocytes within the murine heart valves at ages important for their post-natal development. In all stages analyzed in our study, melanocytes were found in high numbers populating the atrial aspect of the tricuspid and mitral leaflets. The pulmonary valve did not present melanocytes. To characterize a putative role for the valve melanocytes, the dynamic nanomechanical properties of tricuspid leaftets containing large numbers or no melanocytes were measured. The stiffness coefficient of hyperpigmented leaflets was higher (11.5 GPa) than the ones from wild-type (7.5 GPa) and hypopigmented (5.5 GPa) leaflets. These results suggest that melanocytes may contribute to the mechanical properties of the heart valves. The arrangement of extracellular matrix molecules such as Collagen I and Versican B is responsible for the mechanical characteristics of the leaflets. Melanocytes were found to reside primarily in areas of Versican B expression. The patterns of expression of Collagen I and Versican B were not, however, disrupted in hyper or hypopigmented leaflets. Melanocytes may affect other extracellular matrix molecules to alter the valves' microenvironment.
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL, USA.
authors.forename: Flavia
authors.initials: F
authors.lastname: Carneiro
authors.affiliation: Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ, USA.
authors.forename: Boudewijn Pt
authors.initials: BP
authors.lastname: Kruithof
authors.affiliation: Materials and Metallurgical Engineering, Indian Institute of Technology Kanpur, Kanpur, India.
authors.forename: Kanthesh
authors.initials: K
authors.lastname: Balani
authors.affiliation: Nanomechanics and Nanotribology Laboratory, Mechanical and Materials Engineering Department, Florida International University, Miami, FL, USA.
authors.forename: Arvind
authors.initials: A
authors.lastname: Agarwal
authors.affiliation: Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ, USA.
authors.forename: Vinciane
authors.initials: V
authors.lastname: Gaussin
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL, USA.
authors.forename: Lidia
authors.initials: L
authors.lastname: Kos
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000378:metabolism*; D006349:Heart Valve Diseases / Q000473:pathology* / Q000503:physiopathology; D006351:Heart Valves / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL