Overexpression of hyaluronan synthases alters vascular smooth muscle cell phenotype and promotes monocyte adhesion

Abstract

Hyaluronan (HA) accumulates in vascular disease but its functional role is not fully understood. To investigate the impact of HA enriched extracellular matrices (ECM) on cell phenotype, arterial smooth muscle cells (ASMCs) were transduced with retroviral constructs (LXSN) encoding murine has-1, has-2, and has-3. HA synthesis was significantly elevated in has transduced ASMCs. Metabolically labeled HA from has-1 and has-2 transduced cells was present mostly in high molecular weight (HWA) fractions (2-10x10(6) Da), whereas HA produced by has-3 and control cells was present in lower molecular weight fractions (approximately 2x10(6) Da). Both has-1 and has-3 transduced ASMCs accumulated more pericellular HA than has-2 transduced ASMCs. All has transduced ASMCs had attenuated growth and migration rates, and a decreased detachment response. Affinity histochemistry revealed that has-1 transduced ASMCs accumulated the greatest amount of HA containing ECM than the other transduced ASMCs. This ECM was hyaluronidase sensitive and bound a significantly greater number of monocytes than the ECM generated by has-2 or has-3 transduced ASMCs. Confocal microscopy showed CD44 positive monocytes bound to hyaluronidase sensitive ECM in has-1 transduced ASMCs. These data implicate specific has isoforms in the formation of HA enriched pro-inflammatory ECMs.

Expression of Versican V3 by Arterial Smooth Muscle Cells Alters Tumor Growth Factor β (TGFβ)-, Epidermal Growth Factor (EGF)-, and Nuclear Factor κB (NFκB)-dependent Signaling Pathways, Creating a Microenvironment That Resists Monocyte Adhesion

“…Indeed, our data show that hyaluronan accumulation as well as Has1 levels are reduced by V3 expression. Interestingly, a previous study by our group has shown that the ECM produced by ASMCs overexpressing Has1 bound more monocytes than ECMs produced by ASMCs overexpressing Has2 and Has3 (70). Such results implicate Has1 in this monocyte-adhesive ECM phenotype.…”

Substrate-induced phenotypic switches of human smooth muscle cells: anin vitrostudy of in-stent restenosis activation pathways

“…Previously published data showed that macrophages adhering on St acquire a postinflammatory phenotype and undergo transdifferentiation into myofibroblast-like cells [5,6,31]. Therefore, it can be speculated that the synthesis of high-molecular-weight HA by St-adhering SMCs, in combination with a relatively low scavenger activity by the macrophages, may lead to an accumulation of this polysaccharide around the stent struts [35][36][37][38].…”

Hyaluronan-dependent pericellular matrix☆

“…Increased hyaluronan synthesis induced by HAS1 overexpression led to increased hyaluronan cable formation and promoted hyaluronan-dependent monocyte binding, while overexpression of HAS1, 2, or 3 all promoted resistance to cell detachment by trypsin/EDTA and decreased migration and proliferation in SMC [50]. In contrast, increased HAS2 expression in proximal tubular kidney epithelial cells led to increased pericellular hyaluronan but inhibited cable formation [51].…”

“…Long cables are not typically seen on the leading lamellipodia of migrating fibroblasts, indicating that the large cable structures are not necessarily required for locomotion, and may actually impede migration ( [50] and Evanko and Wight, unpublished observation). The activation of latent hyaluronan synthesis activity from predominantly perinuclear regions, particularly under conditions of ER stress suggests that cable formation may be initiated in the perinuclear and or endoplamic reticulum membranes [45,47].…”

“…Hyaluronan cables promote the adhesion of monocytes in inflammatory environments in cell culture and within tissues such as inflamed intestinal mucosa and kidney [38,46,50,98]. The high degree of crosslinking of hyaluronan within the cables would create a more stable structure and more ordered presentation of hyaluronan and/or its associated proteins, which can influence receptor clustering and intracellular signaling.…”