Deletion of Hyaluronan Synthase 3 Inhibits Neointimal Hyperplasia in Mice

Abstract

Objective Hyaluronan (HA) is a polymeric glucosaminoglycan that forms a provisional extracellular matrix in diseased vessels. HA is synthesized by three different HA-synthases (HAS1, -2, -3). Aim of this study was to unravel the role of the HAS3 isoenzyme during experimental neointimal hyperplasia. Approach and Results Neointimal hyperplasia was induced in Has3-deficient mice by ligation of the carotid artery. HA in the media of Has3-deficient mice was decreased 28 days after ligation and neointimal hyperplasia was strongly inhibited. However, medial and luminal areas were unaffected. Cell density, proliferation, and apoptosis were not altered, suggesting a proportional decrease of both the number of cells and extracellular matrix. In addition, endothelial function as determined by acetylcholine-induced relaxation of aortic rings and immunoblotting of endothelial nitric oxide synthase and arterial blood pressure were not affected. Furthermore, the oxidative stress response was not affected as determined in total protein extracts from aortae. Transcriptome analysis comparing control versus ligated carotid arteries hinted towards a mitigated differential regulation of various signaling pathways in Has3-deficient mice in response to ligation that were related to VSMC migration including focal adhesions, integrins, MAPK, and phosphatidylinositol signaling system. Lentiviral overexpression of HAS3 in vascular smooth muscle cells (VSMC) supported the migratory phenotype of VSMC in response to PDGF-BB in vitro. Accordingly, knock down of HAS3 reduced the migratory response to PDGF-BB and in addition decreased the expression of PDGF-B mRNA. Conclusion HAS3-mediated HA synthesis after vessel injury supports seminal signaling pathways in activation of VSMC, increases PDGF-BB-mediated migration, and in turn enhances neointimal hyperplasia in vivo.

Hyaluronan synthase 3 promotes plaque inflammation and atheroprogression

“…On the one hand, the current data are in line with a local effect of macrophage-released IL-1β on HAS3 expression in vascular SMC. In the light of the previous results that HAS3 promotes neointimal hyperplasia in vivo and migration and proliferation of SMC in vitro [12] it is likely that IL-1β thereby also promotes SMC dependent aspects of atheroprogression because HAS3 will create an HA- rich microenvironment.…”

“…Has3 -deficient mice were generated by genOway (Lyon Cedex, France) as described by Kiene et al [12] and then crossbred with Apoe -deficient mice (Taconic; Hudson, NY, USA).…”

“…Therefore, mainly these two functions have been attributed to HA during neointimal hyperplasia and atherosclerosis: proliferation and migration of SMC [11]. Evidence from animal studies support this role by showing proliferating SMC in HA-rich areas of the neointima [7] and decreased neointimal hyperplasia in Has3- deficient mice [12]. Therefore, it is thought that HA creates a permissive matrix for SMC-mediated neointimal hyperplasia.…”

Vascular Smooth Muscle Cells

“…61 Kiene et al reported an important role for hyaluronic acid synthase (HAS)-3 during neointimal formation in mice. 62 When examined 28d after carotid ligation injury in HAS3-deficient mice, HA content of the artery wall was greatly reduced and formation of a neointima was strongly inhibited compared to wild type animals. 62 Transcriptome analysis in HAS3-deficient carotid arteries suggested that genes involved in cell migration including focal adhesion proteins, SMC integrins, and PDGF-BB signal pathway mediators were downregulated.…”

“…62 When examined 28d after carotid ligation injury in HAS3-deficient mice, HA content of the artery wall was greatly reduced and formation of a neointima was strongly inhibited compared to wild type animals. 62 Transcriptome analysis in HAS3-deficient carotid arteries suggested that genes involved in cell migration including focal adhesion proteins, SMC integrins, and PDGF-BB signal pathway mediators were downregulated. The authors conclude that HAS3-mediated hyaluronan production supports important steps in SMC migration and neointimal formation in vivo .…”