Angiotensin II induces expression of inflammatory mediators in vascular adventitial fibroblasts / 生理学报

Vascular adventitial fibroblasts (AF) may play an important role in vascular inflammation. This study was aimed to investigate the expression pattern of inflammatory mediators in AF induced by angiotensin II (AngII) and to explore the effects of AF-derived inflammatory mediators on the adhesion and migration of macrophages both in vitro and in vivo. We used real-time RT-PCR to detect the mRNA expression of inflammatory mediators in cultured AF. The results showed that AngII (1 × 10(-7) mol/L) up-regulated mRNA expression of 4 inflammatory mediators, including P-selectin, ICAM-1, IL-6 and MCP-1, in cultured AF. Western blot analysis or ELISA revealed that AngII up-regulated P-selectin and ICAM-1 protein expression and IL-6 secretion in cultured AF, but did not alter MCP-1 secretion. We further detected the effects of AF-derived inflammatory mediators on the adhesion and chemotaxis of RAW264.7, a macrophage cell line. We found that AF stimulated with AngII could enhance the adhesion of RAW264.7 and the conditioned medium from AngII-stimulated AF could enhance the migration of RAW264.7. Immunofluorescence study showed an enhanced accumulation of CD68 positive cells and the up-regulation of P-selectin, ICAM-1, IL-6 and MCP-1 in aortic adventitia of AngII-infused (200 ng/kg per min for 2 weeks) rats. We concluded that AF may contribute to vascular inflammation via expression of certain inflammatory mediators and the subsequent adhesion and chemotaxis of macrophages.

RhoA-Rho kinase signaling pathway mediates adventitial fibroblasts differentiation to myofibroblasts induced by TGF-β1 / 生理学报

Vascular adventitial fibroblasts (AF) differentiation to myofibroblasts (MF) is the critical physiopathologic feature of vascular remodeling. This study was to investigate the role of RhoA-Rho kinase signaling pathway in AF differentiation to MF induced by transforming growth factor β1 (TGF-β1). The results showed that TGF-β1 up-regulated total RhoA protein expression and RhoA activity in cultured AF by Western blotting and Rho pull-down assay, respectively. TGF-β1 up-regulated phospho-Myosin phosphatase target subunit (MYPT1, a downstream substrate of Rho kinase) expression without altering Rho kinase protein expression, indicating TGF-β1 induced the enhancement of activity of Rho kinase. Ad-N19RhoA-hrGFP virus infection and Y27632, a specific inhibitor of Rho kinase, dose-dependently inhibited TGF-β1-induced α-SM-actin and Calponin expression, as markers of MF differentiation. In conclusion, the RhoA-Rho kinase pathway is involved in AF differentiation to MF induced by TGF-β1.

Adenovirus mediated N19RhoA gene transfer attenuates neointimal formation in rats after carotid artery balloon injury / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the role of small G-protein RhoA in neointimal formation following rat carotid artery balloon injury and related mechanisms.</p><p><b>METHODS</b>Male 3-4-month-old Sprague-Dawley rats were used in the present study (10 rats per group). Group A: control; Group B: carotid artery balloon injury; Group C: injury + Ad-CMV-eGFP + Pluronic F-127; Group D: injury + Ad-CMV-N19RhoA-eGFP + Pluronic F-127; Group E: non injury + Ad-CMV-eGFP + Pluronic F-127. Perivascular gene transfer of an adenovirus co-expressing N19RhoA was performed to rat carotid artery following balloon injury and the effect on neointimal formation and the expressions of PCNA and α-SM-actin examined. Rats were killed after 14 days.</p><p><b>RESULTS</b>The protein expression of RhoA in group B was significantly higher than in group A (P = 0.001), and the positive cells rate of PCNA and α-SM-actin which were assessed by immunohistochemistry in group C (45.2% and 75.6%) was significantly higher than in group D (28.4% and 51.9%, all P < 0.01). The area of neointima was significantly smaller [(0.14 ± 0.08) mm(2) vs. (0.23 ± 0.10) mm(2), P < 0.01], the luminal area was significantly larger [(0.47 ± 0.11) mm(2) vs. (0.31 ± 0.06) mm(2), P < 0.01] in group D than in group C.</p><p><b>CONCLUSION</b>Gene transfer of N19RhoA attenuates neointimal formation after balloon injury in rat carotid arteries possibly related to the modulating capacities of small G-protein RhoA on the proliferation, phenotypic differentiation and migration of vascular adventitial fibroblasts.</p>

Gene profile for differentiation of vascular adventitial myofibroblasts / 生理学报

Our previous study demonstrated that TGF-beta1 could induce the differentiation of vascular adventitial fibroblasts (AFs) to myofibroblasts (MFs). The aim of this study was to identify the genes which might be responsible for the cell phenotypic change using genechips. Cultured rat AFs were treated with TGF-beta1 (10 ng/ml) for 0 min, 5 min, 15 min, 2 h, 12 h and 24 h, respectively. Then the cells were gathered to prepare total RNA. We examined TGF-beta1-induced gene expression profiling using Affymetrix oligonucleotide microarrays and analyzed data by GCOS1.2 software. Moreover, expressional similarity was measured by hierarchical clustering. Some of genechip results were confirmed by real-time quantitative RT-PCR. Microarray analysis identified 2121 genes with a 2-fold change or above after TGF-beta1 stimulation. 1318 genes showed a greater than 2-fold increase and 761 genes were reduced 2 folds or more at mRNA levels, whereas a small portion of the total regulated genes (42 genes) displayed dynamically up- and down-regulated pattern. Genes were further segregated for early (peak at 5 min, 15 min and/or 2 h), late (peak at 12 h and/or 24 h), and sustained (2-fold change or above at five time points) temporal response groups according to the time of their peak expression level. Among 1318 up-regulated genes, 333 genes (25.3%) responded rapidly to TGF-beta1 and 159 genes (12.1%) responded in a sustained manner. Most genes (826, 62.6%) were regulated at 12 h or later. For the 761 down-regulated genes, numbers of early and late responsive genes were 335 (44%) and 267 (36.1%), respectively. There were also 159 genes, 19.9% of total down-regulated genes, decreased at five time points treated by TGF-beta1. The results suggested that the gene expressions of secreted phosphoprotein 1 (APP1) and Rho-associated coiled-coil forming kinase 2 (ROCK2) had the same trends as alpha-smooth muscle-actin, a marker of MF differentiation. In addition, the gene expression of potassium voltage-gated channel, Shal-related family and member 2 (KCND2) was up-regulated. Furthermore, it was found that endothelin 1 (EDN1), some complement components, NADPH oxidase 4 (NOX4) and NAD(P)H dehydrogenase, quinone 1 (NQO1) might be involved in MF differentiation. Using microarrary technique, we confirmed some genes that have been identified by other techniques were implicated in MF differentiation and observed new genes involved in this process. Our results suggest that gene expression profiling study is helpful in identifying genes and pathways potentially involved in cell differentiation.