Lp3/Hapln3, a novel link protein that co-localizes with versican and is coordinately up-regulated by platelet-derived growth factor in arterial smooth muscle cells

Abstract

Link proteins (LPs) belong to the link-module superfamily, which can stabilize and enhance the binding of lecticans to hyaluronan. We report here the identification and characterization of a novel rat link protein gene (Lp3/Hapln3). The deduced protein sequence shares the typical modular elements of link proteins and has an estimated mass of 39 kDa. Examination of the rat genomic DNA sequence revealed that Lp3/Hapln3 and aggrecan genes were paired on chromosome 1q31. Another LP gene and the lectican gene were also paired at a different locus, as they are in the human and mouse genomes. Immunohistochemical analysis showed the prominent expression of Lp3/Hapln3 in the smooth muscle tissues of the vascular wall and gastrointestinal tract. Further comparative studies revealed that Lp3/Hapln3 was well co-localized with versican around the smooth muscle cells of blood vessels but not around endothelial cells. In vitro experiments using primary cultured rat arterial smooth muscle cells (ASMCs) demonstrated the coordinated up-regulation of Lp3/Hapln3 and versican by platelet-derived growth factor (PDGF). These data were supported by in vivo studies of a mechanical vascular injury model in mice. Altogether, our results suggest that Lp3/Hapln3 is involved, together with versican and hyaluronan, in the formation of the pericellular matrix of vascular smooth muscle cells.

Extracellular matrix of the central nervous system: from neglect to challenge

“…Since its discovery several decades ago, HAPLN1 Crtl1 has also been detected in brain, where it joins two other link proteins, the CNS-restricted HAPLN2/Bral1 and HPLN4/Bral2 (Bekku et al 2003;Hirakawa et al 2000). Only HAPLN3/Lp3 seems to be absent from the brain parenchyma, however, being expressed by the smooth muscle cells of larger blood vessels (Ogawa et al 2004;Spicer et al 2003).…”

“…Despite this particularity, the expression and binding preferences of link proteins and lecticans seem to be uncoupled from their genomic setup. For instance, HAPLN1/Crtl1 is co-expressed and interacts with aggrecan in cartilage and possibly in brain, while versican, V0 and V1, and HAPLN3/Lp3 are both synthesized in smooth muscle tissues and may bind to each other at these locations (Ogawa et al 2004). Alternatively, the same versican isoforms or neurocan may team up with HAPLN1/ Crtl1 to form ternary complexes with hyaluronan during brain development (Hirakawa et al 2000;Matsumoto et al 2003;Rauch et al 2004;Seyfried et al 2005;Shi et al 2004).…”

Versican is induced in infiltrating monocytes in myocardial infarction

“…The probe for versican cDNA used for Northern blotting was the same as recently reported [23]. The membranes were hybridized with α 32 P-labelled cDNA probes at 65 °C for 3 hr.…”

“…Immunohistochemical analysis was performed as previously reported [12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Connective tissue growth factor induction in a pressure-overloaded heart ameliorated by the angiotensin II type 1 receptor blocker olmesartan

“…20,21 After treatment, the total RNA of the cells was isolated using RNA STAT-60 reagent (TEL-TEST) and stored in aliquots at À80 1C. Total RNA (2 mg) was reverse-transcribed according to the manufacturer's protocol (Superscript II Amplification System for First Strand cDNA Synthesis; Invitrogen, Carlsbad, CA, USA).…”