Lemire J M, Potter-Perigo S, Hall K L, Wight T N, Schwartz S M
Department of Pathology, University of Washington, Seattle 98195-7470, USA.
Arterioscler Thromb Vasc Biol. 1996 Jun;16(6):821-9. doi: 10.1161/01.atv.16.6.821.
Smooth muscle cells (SMCs) with distinct phenotypes are present in blood vessels, and distinct culture types appear when SMCs are maintained in vitro. For example, cultured SMCs from rat adult media grow as bipolar cells, which differ in gene expression from the predominantly cobblestone-shaped SMCs from rat pup aortas and rat neointimas that we call pi SMCs. Since proteoglycans are present at different concentrations in the normal intima and media and are elevated in atherosclerotic plaque, we sought to determine whether pi and adult medial SMC types synthesize different or unique proteoglycans that are characteristic of each phenotype. [35S]sulfate-labeled proteoglycans were purified by ion-exchange chromatography. An adult medial SMC line synthesized a large proteoglycan (0.2 Kav on Sepharose CL-2B) that was not detectable in a pi SMC line. Digestion of this proteoglycan with chondroitin ABC lyase revealed three core glycoproteins of 330, 370, and 450 kD. By Western blot analysis, the two smallest of these reacted with two antibodies to the human fibroblast proteoglycan versican. RNAs hybridizing to versican probes were found only in adult medial-type SMCs, including an adult medial type clone from pup aorta, by Northern blot analysis. Both SMC types synthesize RNAs that hybridize to probes for other proteoglycans, such as perlecan, biglycan, and decorin. We conclude that rat pi SMC cultures, unlike monkey, human, and rat adult medial SMC cultures, express little or no versican. This difference in expression may be responsible for the different morphologies and growth properties of the two cell types.
具有不同表型的平滑肌细胞（SMC）存在于血管中，当SMC在体外培养时会出现不同的培养类型。例如，来自成年大鼠中膜的培养SMC呈双极细胞生长，其基因表达与来自大鼠幼崽主动脉和大鼠新生内膜的主要呈鹅卵石状的SMC（我们称为pi SMC）不同。由于蛋白聚糖在正常内膜和中膜中的浓度不同，且在动脉粥样硬化斑块中升高，我们试图确定pi SMC和成年中膜SMC类型是否合成不同或独特的蛋白聚糖，这些蛋白聚糖是每种表型的特征。通过离子交换色谱法纯化[35S]硫酸盐标记的蛋白聚糖。一个成年中膜SMC系合成了一种大蛋白聚糖（在琼脂糖CL - 2B上的 Kav为0.2），而在一个pi SMC系中未检测到。用软骨素ABC裂解酶消化这种蛋白聚糖后，发现了三种核心糖蛋白，分子量分别为330、370和450 kD。通过蛋白质印迹分析，其中两个最小的与两种针对人成纤维细胞蛋白聚糖多功能蛋白聚糖的抗体发生反应。通过Northern印迹分析，仅在成年中膜型SMC中发现了与多功能蛋白聚糖探针杂交的RNA，包括来自幼崽主动脉的成年中膜型克隆。两种SMC类型都合成与其他蛋白聚糖（如基底膜聚糖、双糖链蛋白聚糖和饰胶蛋白聚糖）探针杂交的RNA。我们得出结论，与猴、人和成年大鼠中膜SMC培养物不同，大鼠pi SMC培养物很少或不表达多功能蛋白聚糖。这种表达差异可能是这两种细胞类型具有不同形态和生长特性的原因。
