CHARACTERIZATION OF EXTRACELLULAR-MATRIX PROTEOGLYCAN TRANSCRIPTS EXPRESSED BY VASCULAR SMOOTH-MUSCLE CELLS

Google Scholar
  • 1 June 1990
    • journal article
    • research article
    • Vol. 52  (1) , 98-104
Abstract
Northern blot analysis using intraspecies and cross-species cDNA probes encoding a variety of proteoglycan (PG) core proteins was employed to examine in vitro and in vivo vascular smooth muscle cell (VSMC) extracellular matrix (ECM) PG gene expression. Similar studies were performed using a cDNA probe encoding the rat chondrosarcoma link protein. VSMCs maintained in vitro as well as in vivo expressed a 1.8 kb transcript homologous to a cDNA encoding the bovine bone small PGII. Densitometric analysis revealed an 11-fold increase in the in vivo level of this transcript when compared to an equivalent amount of RNA extracted from rat VSMCs maintained in vitro. Rat aorta medial tissue contained approximately a 10-fold higher level of the bovine bone PG11 homologous transcript when compared to rat chrondrosarcoma tissue. A 2.9 kb transcript homologous to a cDNA encoding the human bone small PGI (biglycan) was detected in poly(A)+ RNA isolated from rat VSMCs maintained in vitro as well as within rat thoracic aorta medial tissue. Densitometric analysis revealed a 0.55-fold increase in the in vitro level of the PGI transcript when compared to in vivo levels. Rat chondrosarcoma expressed approximately a 3-fold higher level of a human bone PGI homologous transcript when compared to rat aorta medial tissue. A 7.3 kb and an 8.4 kb transcript homologous to a cDNA encoding the rat chondrosarcoma large hyaluronic acid (HA) binding chondroitin-sulfate (CS) PG core protein was detected in poly(A)+ RNA extracted from rat VSCMs maintained in vitro. Similar analyses conducted on poly(A)+ RNA isolated from pigeon aorta medial tissue detected at 2.7 kb transcript homologous to the bovine bone small PGII cDNA. RNA isolated from rabbit aorta medial tissue did not contain any transcripts homologous to this cDNA probe. Instead, poly(A)+ RNA recovered from rabbit aorta medial tissue did contain a 2.4 kb transcript homologous to the human bone small PGI cDNA whereas RNA isolated from similar tissue recovered from pigeon did not contain any transcripts homologous to this probe. None of the above poly(A)+ RNA samples examined in this study contained transcripts homologous to the rat chondrosarcoma link cDNA. Transcripts homologous to cDNA probes derived from the rat chondrosarcoma large HA binding CSPG were not detected in poly(A)+ RNA isolated from rat, rabbit and pigeon aorta medial tissue under the conditions employed for Northern blot analysis. Our results provide evidence for species variation and differences in in vitro and in vivo levels of transcripts encoding various VSMC ECM PGs as well as tissue specific differences in the levels of transcripts encoding small ECM PGs.

This publication has 1 reference indexed in Scilit: