Radhakrishnamurthy B, Srinivasan S R, Eberle K, Ruiz H, Dalferes E R, Sharma C, Berenson G S
Department of Medicine, Louisiana State University Medical Center, New Orleans 70112.
Biochim Biophys Acta. 1988 Feb 17;964(2):231-43. doi: 10.1016/0304-4165(88)90171-7.
The synthesis of proteoglycans by aorta explants from rabbits with diet-induced atherosclerosis and controls was studied by 35S-incorporation. Proteoglycans were isolated under dissociative conditions from incubation medium and from arterial explants. Additionally, the tissue proteoglycans that were not extracted by 4 M guanidine-HCl were solubilized by digestion of the tissue by elastase in the presence of proteinase inhibitors. The residual tissue was hydrolyzed by papain and glycosaminoglycans were isolated. The atherosclerotic aorta tissue incorporated twice the amount of 35S into proteoglycans than observed for controls; in both groups about 70% of the label incorporated into the tissue was noted in the proteoglycans extracted by guanidine-HC;, while about 30% of the total 35S-labeled proteoglycans synthesized by the explants were found in the media. Atherosclerotic tissue incorporated 35S predominantly into chondroitin sulfate proteoglycans when compared to control tissue. The chondroitinase ABC-digestable proteoglycans that were extracted by guanidine-HCl from atherosclerotic tissues were of larger molecular size than those from control tissue, but the core proteins from these preparations were similar. The heparan sulfate proteoglycan that was obtained by dissociative extraction from atherosclerotic tissue had greater amounts of N-acetyl and lesser amounts of N-sulfate ester groups than the preparation from control tissue. Digestion of the tissue by elastase yielded heparan sulfate proteoglycan as the major constituent in both groups, although atherosclerotic tissue contained relatively small amounts of this proteoglycan. The residual tissue from both groups contained chondroitin sulfate and heparan sulfate as the major glycosaminoglycans with the latter showing a decrease with atherosclerosis. Atherosclerotic tissue secreted into the medium about two-fold more 35S-labeled proteoglycans with larger molecular size than control tissue; proteoglycans of the heparan sulfate and chondroitin sulfate types were the major constituents in the culture medium of both tissues. Thus, proteoglycans undergo both quantitative and qualitative changes in atherosclerosis, reflecting the enhanced smooth muscle cell activity. These changes are potentially important in modulating lipoprotein binding and hemostatic properties, as well as fibrillogenesis of the arterial wall.
通过35S掺入法研究了饮食诱导的动脉粥样硬化兔和对照兔主动脉外植体中蛋白聚糖的合成。在解离条件下从孵育培养基和动脉外植体中分离蛋白聚糖。此外，未被4M盐酸胍提取的组织蛋白聚糖通过在蛋白酶抑制剂存在下用弹性蛋白酶消化组织而溶解。残留组织用木瓜蛋白酶水解并分离糖胺聚糖。动脉粥样硬化主动脉组织掺入蛋白聚糖中的35S量是对照的两倍；在两组中，约70%掺入组织的标记物存在于用盐酸胍提取的蛋白聚糖中，而外植体合成的总35S标记蛋白聚糖中约30%存在于培养基中。与对照组织相比，动脉粥样硬化组织主要将35S掺入硫酸软骨素蛋白聚糖中。用盐酸胍从动脉粥样硬化组织中提取的可被软骨素酶ABC消化的蛋白聚糖的分子大小比对照组织的大，但这些制剂的核心蛋白相似。通过解离提取从动脉粥样硬化组织中获得的硫酸乙酰肝素蛋白聚糖比对照组织的制剂含有更多的N-乙酰基和更少的N-硫酸酯基团。用弹性蛋白酶消化组织在两组中均产生硫酸乙酰肝素蛋白聚糖作为主要成分，尽管动脉粥样硬化组织中这种蛋白聚糖的含量相对较少。两组的残留组织均以硫酸软骨素和硫酸乙酰肝素作为主要糖胺聚糖，后者在动脉粥样硬化时减少。动脉粥样硬化组织分泌到培养基中的35S标记蛋白聚糖比对照组织多约两倍，分子大小也更大；硫酸乙酰肝素和硫酸软骨素类型的蛋白聚糖是两种组织培养基中的主要成分。因此，蛋白聚糖在动脉粥样硬化中发生了数量和质量的变化，反映了平滑肌细胞活性的增强。这些变化在调节脂蛋白结合和止血特性以及动脉壁的纤维形成方面可能具有重要意义。
