Cloning the full-length cDNA of a gene responsible for vascular smooth muscle cell proliferation in atherogenesis and study of function / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To clone the full-length cDNA of a gene responsible for vascular smooth muscle cell (v-SMC) proliferation in atherogenesis, and study its function.</p><p><b>METHODS</b>Oxidized low density lipoprotein (ox-LDL) at optimal concentration was used as the stimulant to induce v-SMC proliferation in culture medium. A cDNA subtractive library of v-SMC proliferation specific to ox-LDL stimulation was established using subtractive hybridization technique. Methods, including blotting, Northern hybridization and gene sequencing, were used to clone new gene fragments. By using full-length cDNA screening and protein expression techniques, one full-length cDNA was cloned and its function was studied.</p><p><b>RESULTS</b>One full-length cDNA was cloned. The new gene (Genbank AF 174647) expressed a 44 kDa protein, which might be associated with the activity of ox-LDL.</p><p><b>CONCLUSION</b>The new gene cloned may be associated with SMC proliferation in atherogenesis.</p>

Nanoparticle as a new gene transferring vector in specific expression gene.

OBJECTIVE: To evaluate the possibility and efficiency of nanoparticle as a new vector in specific gene transference. METHODS: Nanoparticle-DNA complex was prepared with Poly-dl-lactic-co-glycolic acid (PLGA) bearing anti-sense monocyte chemotactic protein-1 (A-MCP-1), a specific expression gene, and the package efficiency, release progress in vitro, and the size of the complex were determined. The possibility of the new vector was evaluated with genomic DNA PCR by transferring gene into cultured smooth muscle cells (SMC), cationic lipids as a control. For study in vivo, jugular vein-to-artery bypass grafting procedures were performed on 20 New Zealand white rabbits, of which 6 grafts were transferred with nanoparticle-A-MCP-1 (200 microg), 6 with A-MCP-1 (200 microg) by cationic liposome, 4 with LNCX plasmid, and 4 as control. Fourteen days after the grafts were harvested, the expression of A-MCP-1 and its effect on MCP-1 in vein grafts were detected by dot blot, and the morphologic evaluation of grafts was performed. RESULTS: The package efficiency of the nanoparticle-DNA complex was 0.9%, release progress in vitro lasted 2 weeks, and the size ranged from 150 to 300 nm. SMC genomic DNA PCR showed that A-MCP-1 gene could be successfully transfected into cells by nanoparticle. The study in vivo indicated that A-MCP-1 mRNA was expressed in both local gene delivery groups, nanoparticle and liposome, meanwhile, MCP-1 expression in vein grafts was significantly inhibited and neointimal hyperplasia was notably reduced. CONCLUSION: Nanoparticle can act as a vector to transfect specific gene.

Effect of NF-kappaB on the induction of PDGF-B transcription by angiotensin II in the ECV304 cell line / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To examine the effect of angiotensin II (Ang II) on nuclear factor-kappa B (NF-kappaB) activation in human endothelial cell line ECV304 and the molecular mechanism by which Ang II activates NF-kappaB.</p><p><b>METHODS</b>ECV304 cells were transiently cotransfected with an NF-kappaB/luciferase reporter gene and inactive NF-kappaB-inducing kinase (NIK), IkappaB kinase alpha (IKK(alpha)), IkappaB kinase beta (IKK(beta)) mutants or vectors, respectively. The effect on NF-kappaB was detected by using an electrophoretic mobility shift assay (EMSA) and overexpression of the mutants enabled blocking of reporter gene activation induced by Ang II. With immunofluorescence and immuno-electronic microscope techniques, including confocal microscopy and gold particle labeled electronic microscopy, definite cytoplasmic-to-nuclear translocations of NF-kappaB activation were detected using subunits p50 and p65 induced by Ang II.</p><p><b>RESULTS</b>The translocation of p50 in nuclei was highly remarkable 2 hours after Ang II stimulation, and the activity was somewhat reduced 6 hours after stimulation to the 18th hour. Northern blot also showed PDGF-B mRNA increased by stimulation of Ang II for 18 hours.</p><p><b>CONCLUSION</b>Ang II is effective in stimulating NF-kappaB activation through a pathway dependent on NIK, IKK(alpha) and IKK(beta), and induces PDGF-B transcription in the endothelial cell line, ECV304.v</p>

Effect of oxLDL on the uptake and clearance rate of cholesterol in v-SMC originated from human apoA1 transgenic mice / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To study the inhibition effect of oxLDL on the uptake and clearance of intra-cellular (3)H-cholesterol in v-SMC from the human-apoA1 transgenic mice (C57BL/6) and the changes in human-apoA1 mRNA expression in v-SMC from human apoA1 transgenic mice after oxLDL stimulation.</p><p><b>METHODS</b>v-SMC originally isolated from human apoA1 transgenic mice connected with a recombined mouse metallothionein-I (MT-I) promoter was used, and the effect of oxLDL on the uptake and clearance of intracellular (3)H-cholesterol was studied in v-SMC of the transgenic and control mice respectively, the study of h-apoA I mRNA expression from v-SMC of the transgenic mice were done by RT-PCR and Northern blot.</p><p><b>RESULTS</b>oxLDL (30 microg/ml) strongly promoted the SMC proliferation. No difference was found in (3)H-cholesterol uptake between nSMC and trSMC, and the uptake rates of both kinds of SMC rose 100% after oxLDL stimulation. The efflux rates of (3)H-cholesterol in trSMC were much higher than those of nSMC (40% - 50%). After oxLDL stimulation, the clearance rates fell by 28% and 10%, respectively, for nSMC and trSMC. The result of RT-PCR and Northern blot showed that h-apoA1 gene expression was markedly increased by the stimulation of oxLDL.</p><p><b>CONCLUSION</b>Expression of the h-apoA1 gene in C57BL/6 mice enables them to reduce the accumulation of cholesterol in v-SMC. The trSMC can alleviate the harmful effect of oxLDL due to the increase of h-apoA1 expression.</p>

Expression of antisense thrombin receptor gene inhibits intimal hyperplasia of rat carotid artery after balloon injury / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the mechanism of restenosis after angioplasty and to clarify the effect of thrombin and its receptor on restenosis development.</p><p><b>METHODS</b>Balloon catheter-induced injury was adopted to induce intimal hyperplasia of the carotid arteries in rats. Antisense thrombin receptor (ATR) cDNA was transfected by perfusing recombinant LXSN ATR plasmid/nanoparticle complex into the segment of the injured carotid artery.</p><p><b>RESULTS</b>PCR result showed integration of the recombined gene. Dot blot showed the expression of antisense TR mediated by recombinant LXSN ATR plasmid/nanoparticle complex in the wall of common carotid arteries of the experimental group rats, which enabled to inhibit TR gene expression and intimal hyperplasia of the injured arteries.</p><p><b>CONCLUSIONS</b>Thrombin and its receptor play an important role in the formation of neointima after the injury, which provides a potential clue in developing a new approach for prevention and treatment of restenosis after angioplasty.</p>