CORRECTIVE FACTORS FOR INBORN ERRORS OF MUCOPOLYSACCHARIDE METABOLISM
CORRECTIVE FACTORS FOR INBORN ERRORS OF MUCOPOLYSACCHARIDE METABOLISM
复制标题
DOI：
10.1111/j.1749-6632.1971.tb46934.x
复制
发表时间：
1971-01-01
影响因子：
5.2
通讯作者：
CANTZ, MJ
中科院分区：
文献类型：
--
作者：
NEUFELD, EF;CANTZ, MJ
本文将介绍一种“替代疗法”培养的成纤维细胞，缺乏某些生物活性的蛋白质，因为基因突变。有缺陷的成纤维细胞来自先天性粘多糖代谢缺陷的患者：Hurler，Hunter和Sanfilippo综合征。从遗传学上讲，这三种疾病是不同的。在临床上，它们非常相似，以至于不是这类疾病专家的儿科医生可能很难区分两者，特别是在早期阶段;在生物化学上它们属于同一类，因为所有三种都以过量的粘多糖为特征（硫酸皮肤素和/或单硫酸乙酰肝素）在尿中排泄并在细胞内沉积在诸如肝和脾的组织中。Danes和Beam以及Matalon和Dorfman 3表明，从这些患者的皮肤中培养的成纤维细胞同样积累粘多糖，随后被鉴定为硫酸determatan。尽管这些罕见的疾病以前只能在活检或尸检材料中进行研究，但现在可以在uitm中对基因标记的细胞进行生物化学研究，这些细胞可以相对大量地生长。1967年，本实验室进行了细胞内粘多糖积累动力学的研究，以确定它是否是由于过度合成或利用率降低而发生的。Fratantoni和同事使用%04作为粘多糖的标记物，注意到在所有成纤维细胞中同时进行几个过程。合成粘多糖，一部分（约3/4）迅速分泌到培养基中;其余部分转移到储存池中，唯一的出路是降解。此外，有一些分泌的粘多糖的再摄取和随后的降解。导致合成和分泌的所有池的周转（即，SO 4的运输和活化、蛋白多糖的生物合成和硫酸化以及其向细胞外部的运输）非常迅速，所有这些池在不到一小时内变得用%04饱和。另一方面，储存池（溶酶体？）在几天而不是几分钟的时间尺度上周转;它比生物合成和分泌池大得多，并且占细胞内粘多糖的大部分。通过检查各种过程的速率，可以得出结论，在Hurler和Hunter综合征中，合成、分泌和积累的速率不受影响，但降解减少。这并不意味着Hurler和Hunter成纤维细胞不会降解粘多糖;相反，它们允许储存池扩大并以几天甚至一周的半衰期更慢地翻转，而正常成纤维细胞的半衰期为8小时。如果降解途径中的某些酶的活性降低或对其底物的亲和力降低，则会出现这种情况。最近，Wiesmann及其同事检查了来自Sanfilippo综合征患者的成纤维细胞，发现这些成纤维细胞也具有增加的粘多糖积累和延长的周转时间，尽管没有达到Hurler和Hunter成纤维细胞的程度。6
This paper will describe a “replacement therapy” for cultured fibroblasts which lack certain biologically active proteins because of genetic mutation. The defective fibroblasts in question are derived from patients with inborn errors of mucopolysaccharide metabolism: the Hurler, Hunter and Sanfilippo syndromes.‘Genetically, the three disorders are distinct. Clinically, they are sufficiently similar so that pediatricians who are not specialists in this group of disorders may have trouble recognizing one from the other, particularly in the early stages; biochemically they belong to the same class, as all three are characterized by excessive quantities of mucopolysaccharide (dermatan sulfate and/or heparan monosulfate) excreted in the urine and deposited intracellularly in such tissues as liver and spleen.In 1965-1966, Danes and Beam’and Matalon and Dorfman3 showed that fibroblasts cultured from the skin of such patients likewise accumulate mucopolysaccharide, subsequently identified as determatan~ ulfate.~ Whereas these rare disorders could previously be studied only in biopsy or autopsy material, it now became possible to perform biochemical studies in uitm on genetically marked cells, which could be grown in relatively large quantities. In 1967, this laboratory undertook a study of the kinetics of intracellular mucopolysaccharide accumulation, to determine if it occurred because of oversynthesis or reduced utilization. Using% 04 as a marker for mucopolysaccharide, Fratantoni and associates’ noted that several processes went on simultaneously in all fibroblasts. Mucopolysaccharide is synthesized, and a portion (about 3/4) is promptly secreted into the medium; the remainder is diverted into a storage pool from which the only way out is by degradation. In addition, there is some reingestion and subsequent degradation of secreted mucopolysaccharide. The turnover of all the pools leading to synthesis and secretion (ie, transport and activation of SO4, biosynthesis and sulfation of proteinpolysaccharide and its transport to the cell exterior) is very rapid, all these pools becoming saturated with% 04 in less than an hour. On the other hand, the storage pool (lysosomal?) turns over on a time scale of days rather than minutes; it is much larger than the biosynthetic and secretory pools, and accounts for most of the intracellular mucopolysaccharide. By examining the rates of the various processes, it was concluded that the rates of synthesis, secretion and accumulation are not affected in the Hurler and Hunter syndromes, but that degradation is reduced. This does not mean that Hurler and Hunter fibroblasts do not degrade mucopolysaccharide; rather, they allow the storage pool to expand and turn it over more slowly with a half life of several days or even a week, compared to eight hours for normal fibroblasts. This is what one would expect if some enzyme in the degradative pathway had reduced activity or reduced affinity for its substrate. More recently, Wiesmann and coworkers have examined fibroblasts from patients with the Sanfilippo syndrome, and found that these also had an increased accumulation and lengthened turnover time of mucopolysaccharide, though not to the extent of Hurler and Hunter fibroblasts. 6