Berrou E, Breton M, Deudon E, Picard J
Laboratoire de Biochimie, INSERM U 181, Faculté de Médecine Saint-Antoine, Paris, France.
J Cell Physiol. 1988 Dec;137(3):430-8. doi: 10.1002/jcp.1041370306.
The effect of porcine endothelial-cell-conditioned medium on proteoglycan synthesis by pig aorta smooth muscle cells was studied under serum-free conditions. Maximal stimulation of [35S]-sulfate incorporation (50%) into medium-secreted and cell layer proteoglycans was observed after 20 min and 4 h incubation, respectively. This stimulation can be explained neither by increased secretion nor by oversulfation of medium-secreted [35S]-labeled proteoglycans. Those [35S]-proteoglycans secreted (for 24 h) in the presence of endothelial cell-conditioned medium were characterized by a higher hydrodynamic size than those secreted in the presence of control medium, without modification of glycosaminoglycan chain length. Agreement between the stimulation of incorporation of [35S]-sulfate into glycanic chains (50.1%) and [14C]-serine residues associated with glycosaminoglycans (49.9%) involved an increase in the number of glycanic chains linked to protein cores. The lesser stimulation of [14C]-serine incorporation into secreted proteins (18%) suggested that stimulation of glycosaminoglycan synthesis was not the direct consequence of enhanced protein synthesis. Proteoglycan synthesis was studied in the presence of para-nitrophenyl-beta-D-xyloside. Fractionation of medium-secreted [35S]-proteoglycans and xyloside-initiated glycosaminoglycans revealed that stimulation of [35S]-glycosaminoglycan protein core acceptor for glycanic chain initiation. Our results suggest that the factor(s) secreted by endothelial cells are able to modify smooth muscle cell proteoglycan synthesis by stimulating the first step of protein core glycosylation. This stimulation was accompanied by an increase in proteoglycan hydrodynamic size.
在无血清条件下研究了猪内皮细胞条件培养基对猪主动脉平滑肌细胞蛋白聚糖合成的影响。分别在孵育20分钟和4小时后，观察到培养基分泌的和细胞层蛋白聚糖中[35S] - 硫酸盐掺入的最大刺激（50%）。这种刺激既不能通过培养基分泌[35S] - 标记蛋白聚糖的分泌增加来解释，也不能通过过度硫酸化来解释。在内皮细胞条件培养基存在下分泌（24小时）的那些[35S] - 蛋白聚糖的流体动力学尺寸高于在对照培养基存在下分泌的那些，而糖胺聚糖链长度没有改变。[35S] - 硫酸盐掺入糖链（50.1%）和与糖胺聚糖相关的[14C] - 丝氨酸残基（49.9%）的刺激之间的一致性涉及与蛋白核心连接的糖链数量的增加。[14C] - 丝氨酸掺入分泌蛋白的刺激较小（18%）表明糖胺聚糖合成的刺激不是蛋白质合成增强的直接结果。在对硝基苯基 - β - D - 木糖苷存在下研究了蛋白聚糖的合成。培养基分泌的[35S] - 蛋白聚糖和木糖苷引发的糖胺聚糖的分级分离表明，刺激了[35S] - 糖胺聚糖蛋白核心作为糖链起始的受体。我们的结果表明，内皮细胞分泌的因子能够通过刺激蛋白核心糖基化的第一步来改变平滑肌细胞蛋白聚糖的合成。这种刺激伴随着蛋白聚糖流体动力学尺寸的增加。
