title: Small leucine-rich proteoglycans exhibit unique spatiotemporal expression profiles during cardiac valve development.
abstract: BACKGROUND
  Small Leucine Rich Proteoglycans (SLRPs) play a role in collagen fiber formation and also function as signaling molecules. Given the importance of collagen synthesis to the cardiovascular extracellular matrix (ECM), we examined the spatiotemporal expression of SLRPs, not previously investigated in the murine heart.
  
  
  RESULTS
  Cardiac expression using antibodies specific for biglycan (BGN), decorin (DCN), fibromodulin (FMOD), and lumican (LUM) revealed distinct patterns among the SLRPs in mesenchymal-derived tissues. DCN showed the most intense localization within the developing valve cusps, while LUM was evident primarily in the hinge region of postnatal cardiac valves. BGN, DCN, and FMOD were immunolocalized to regions where cardiac valves anchor into adjacent tissues. Medial (BGN) and adventitial (BGN, DCN, FMOD and LUM) layers of the pulmonary and aortic arteries also showed intense staining of SLRPs but this spatiotemporal expression varied with developmental age.
  
  
  CONCLUSIONS
  The unique expression patterns of SLRPs suggest they have adapted to specialized roles in the cardiovascular ECM. SLRP expression patterns overlap with areas where TGFβ signaling is critical to the developing heart. Therefore, we speculate that SLRPs may not only be required to facilitate collagen fiber formation but may also regulate TGFβ signaling in the murine heart.
authors.affiliation: Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Loren E
authors.initials: LE
authors.lastname: Dupuis
authors.forename: Christine B
authors.initials: CB
authors.lastname: Kern
mesh_terms: D000818:Animals; D004622:Embryo, Mammalian / Q000166:cytology / Q000196:embryology*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006351:Heart Valves / Q000166:cytology / Q000196:embryology*; D051379:Mice; D011509:Proteoglycans / Q000096:biosynthesis*; D015398:Signal Transduction / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D016212:Transforming Growth Factor beta
keywords: arterial wall; biglycan; decorin; fibromodulin; lumican; valves