Key Points
- To investigate the tissue distribution and functional role of latent TGF-beta-binding protein-1 (LTBP-1) during endothelial-mesenchymal transformation in mouse embryonic heart cushion formation.
- Examined embryonic mouse heart tissue localization using an LTBP-1-specific polyclonal antiserum (Ab39) and double antibody staining.
- Visualized extracellular matrix ultrastructure and LTBP-1 distribution using immunogold electron microscopy.
- Assayed endothelial-mesenchymal transformation in atrioventricular endocardial and myocardial cocultures on three-dimensional collagen gels with antibody inhibition and mature TGF-beta rescue.
- LTBP-1 colocalized with TGF-beta-1 as an extracellular fibrillar structure surrounding endocardial cushion mesenchymal cells, specifically within 40-100 nm fibrillar structures and 5-10 nm microfibrils.
- Anti-LTBP-1 antiserum inhibited endothelial-mesenchymal transformation in atrioventricular endocardial cells cultured on collagen gels, and this inhibition was reversed by adding mature TGF-beta protein.
Structured PICO
PPopulationMouse embryonic heart tissue (endocardial cushion tissue) in a three-dimensional collagen gel culture assay
IInterventionAnti-LTBP-1 antiserum (Ab39) and mature TGF beta proteins
OOutcomeEndothelial-mesenchymal transformation and tissue distribution of LTBP-1surrogate
LTBP-1 exists as an extracellular fibrillar structure and plays a crucial role in storing TGF beta as a large latent complex during embryonic heart development.