Laminin production and basement membrane deposition by mesenchymal stem cells upon adipogenic differentiation.

ABSTRACT: The aim was to study laminin (LM) synthesis, integration, and deposition into the basement membrane (BM) during adipogenesis. Human bone marrow-derived mesenchymal stromal cells (MSCs) were induced along the adipogenic lineage. LM chain mRNA and protein levels were followed using quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence (IF) staining, transmission electron microscopy (TEM), and immunoprecipitation. MSCs produced low levels of LM mRNAs but were not surrounded by BM in IF and TEM imaging. LM-?4, LM-?1, and LM-?1 mRNAs increased during adipogenesis 3.9-, 5.8-, and 2.8-fold by day 28. LM-411 was immunoprecipitated from the ECM of the differentiated cells. Immunostaining suggested deposition of LM-411 and some LM-421. BM build-up was probably organized in part by integrin (Int) ?6?1. At day 28, TEM images revealed BM-like structures around fat droplet-containing cells. The first signs of BM formation and Int ?6?1 were seen using IF imaging at day 14. Laminin-411 and Int ?6?1 were expressed in vivo in mature human subcutaneous fat tissue. Undifferentiated human MSCs did not organize LM subunits into BM, whereas LM-411 and some LM-421 are precipitated in the BM around adipocytes. This is the first demonstration of LM-411 precipitation during hMSC adipogenesis around adipocytes as a structural scaffold and Int-regulated signaling element.

SUBMITTER: Noro A 

PROVIDER: S-EPMC3788628 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature