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首页> 外文期刊>Infection and immunity >Effect of streptococcal lipoteichoic acid on prolyl hydroxylase activity as related to collagen formation in mouse fibroblast monolayers.
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Effect of streptococcal lipoteichoic acid on prolyl hydroxylase activity as related to collagen formation in mouse fibroblast monolayers.

机译：链球菌脂蛋白酸对小鼠成纤维细胞单层胶原蛋白脯氨酰羟化酶活性的影响。

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Dried and wet mouse fibroblast monolayers with labeled collagenous substrate were used to study the effects of lipoteichoic acid (LTA) on cellular prolyl hydroxylase activity. LTA is a scavenger of cations, and Fe2+ is essential for prolyl hydroxylase activity. Surprisingly, addition of LTA to dried monolayers resulted in increased prolyl hydroxylase activity, whereas preincubation of Fe2+ with LTA only negated this increase. However, significant inhibition of enzyme activity by wet monolayers occurred whether LTA was added directly to the test system or whether it was used after preincubation with Fe2+. These data suggest that LTA causes membrane perturbations. Also, that the binding of LTA to the membrane of dried and wet monolayers appears to be decidedly different when based on the subsequent availability of Fe2+ for cellular prolyl hydroxylase activity. The ability of LTA to act as a cationic exchanger and the presence of intracellular Fe2+ inaccessible to LTA probably accounted for the lack of complete inhibition of prolyl hydroxylase activity by this amphiphile in the wet cell system. Considerably less iron was needed to negate the partial inhibition of prolyl hydroxylase activity by LTA in viable cells than was needed to restore the increased enzyme activity by this amphiphile in equivalent dried preparations. These and other results showed that, although LTA does not affect collagen polypeptide chain formation in wet monolayers, its involvement at the molecular level does result in a marked decrease in the hydroxylation of collagenous peptidyl prolyl residues through LTA interaction with Fe2+. This reduction in prolyl hydroxylase activity equaled the reduction in hydroxylation of collagenous protein in fibroblast monolayers caused by LTA reported earlier (O. Leon and C. Panos, Infect. Immun. 40:785-794, 1983). Therefore, these data suggest that partial inhibition of prolyl hydroxylase activity is directly related to the synthesis of defective collagen by wet fibroblast monolayers exposed to minute amounts of group A, type 12 streptococcal LTA. Use of LTA also showed that complete inhibition of hydroxyproline formation is not required for the continued formation and accumulation of defective collagenous protein by these monolayers.
机译：使用干的和湿的具有标记胶原底物的小鼠成纤维细胞单层膜，研究脂蛋白壁酸（LTA）对细胞脯氨酰羟化酶活性的影响。 LTA是阳离子的清除剂，Fe2 +对于脯氨酰羟化酶活性至关重要。出人意料的是，在干燥的单层中添加LTA会导致脯氨酰羟化酶活性的提高，而Fe2 +与LTA的预温育只能抵消这种增加。但是，无论是将LTA直接添加到测试系统中还是将其与Fe2 +预温育后一起使用，湿单层都会显着抑制酶活性。这些数据表明LTA会引起膜微扰。同样，当基于随后可利用的Fe2 +用于细胞脯氨酰羟化酶活性时，LTA与干燥和湿润单层膜的结合似乎也明显不同。 LTA充当阳离子交换剂的能力以及LTA难以接近的细胞内Fe2 +的存在可能解释了这种两亲物在湿细胞系统中对脯氨酰羟化酶活性的完全抑制。消除在活细胞中LTA对脯氨酰羟化酶活性的部分抑制所需的铁量要比在同等干燥的制剂中恢复该两亲物增加的酶活性所需的铁量少。这些和其他结果表明，尽管LTA不会影响湿单层胶原蛋白多肽链的形成，但它在分子水平上的参与确实会通过LTA与Fe2 +的相互作用而导致胶原肽基脯氨酰残基的羟基化作用显着降低。脯氨酰羟化酶活性的这种降低等于早先报道的由LTA引起的成纤维细胞单层中胶原蛋白的羟化的降低（O.Leon和C.Panos，Infect.Immun.40：785-794，1983）。因此，这些数据表明脯氨酰羟化酶活性的部分抑制直接与暴露于微量A组12型链球菌LTA的湿成纤维细胞单层合成缺陷胶原有关。使用LTA还显示，对于这些单层继续形成和积累有缺陷的胶原蛋白，并不需要完全抑制羟脯氨酸的形成。

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