Sommer P, Gleyzal C, Raccurt M, Delbourg M, Serrar M, Joazeiro P, Peyrol S, Kagan H, Trackman P C, Grimaud J A
Laboratoire de Physiopathologie Cellulaire et Moléculaire des Fibroses Tissulaires, CNRS URA 1459, Institut Pasteur de Lyon, France.
Lab Invest. 1993 Oct;69(4):460-70.
Murine schistosomiasis provides an experimental model of reversible fibrosis. The lysyl oxidase catalyzes the first step of collagen and elastin enzymatic cross-linking and appears to be a crucial factor in stabilizing the neosynthesized extracellular matrix in the liver.
A cDNA probe encoding a portion of the murine lysyl oxidase was cloned, and antibodies were raised against the corresponding recombinant peptide expressed as a fusion protein. Both tools were used to examine the expression of the lysyl oxidase mRNAs and peptides, all within granulomas and cells extracted from infected liver.
Transient up-regulation of two dominant 4.5 kb and 5.5 kb transcripts was observed among four mRNAs hybridizing with the lysyl oxidase cDNA probe during the development of granulomas. An identical time course was obtained for alpha 1(I) procollagen messenger expression. The lysyl oxidase expression was observed in type I collagen producing cells mainly localized at the periphery of fibroinflammatory granulomas and it disappeared in late granulomas. The lysyl oxidase and type I collagen expressing cells, located within granulomas, exhibited the characteristics of myofibroblasts, as judged by their expression of alpha-smooth muscle actin and desmin and by their ultrastructural morphology. Four antigenically related peptides were immunopurified from an enriched preparation of myofibroblast-like cells extracted from infected mouse liver. Two of these peptides had the molecular weight of prolysyl oxidase (50,000) and activated lysyl oxidase (32,000). The two others (28,000 and 66,000) might correspond to cleavage product or dimeric form respectively.
This study demonstrates that the lysyl oxidase was transiently up-regulated at the transcriptional level parallely to alpha(1)I procollagen within developing granulomas. Myofibroblasts are involved in the expression of the lysyl oxidase which may be secreted as a proenzyme and an activated enzyme.
小鼠血吸虫病提供了一个可逆性纤维化的实验模型。赖氨酰氧化酶催化胶原蛋白和弹性蛋白酶促交联的第一步，似乎是稳定肝脏中新合成的细胞外基质的关键因素。
克隆了编码小鼠赖氨酰氧化酶一部分的cDNA探针，并制备了针对作为融合蛋白表达的相应重组肽的抗体。这两种工具都用于检测赖氨酰氧化酶mRNA和肽在肉芽肿以及从受感染肝脏中提取的细胞中的表达。
在肉芽肿形成过程中，与赖氨酰氧化酶cDNA探针杂交的四种mRNA中，观察到两种主要的4.5 kb和5.5 kb转录本的瞬时上调。α1（I）前胶原信使表达也获得了相同的时间进程。赖氨酰氧化酶表达见于主要位于纤维炎性肉芽肿周边的I型胶原产生细胞，在晚期肉芽肿中消失。位于肉芽肿内的表达赖氨酰氧化酶和I型胶原的细胞，根据其α-平滑肌肌动蛋白和结蛋白的表达以及超微结构形态判断，表现出肌成纤维细胞的特征。从受感染小鼠肝脏中提取的富含肌成纤维细胞样细胞的制剂中免疫纯化出四种抗原相关肽。其中两种肽的分子量分别为脯氨酰氧化酶（50,000）和活化的赖氨酰氧化酶（32,000）。另外两种（28,000和66,000）可能分别对应于裂解产物或二聚体形式。
本研究表明，在发育中的肉芽肿内，赖氨酰氧化酶在转录水平上与α1（I）前胶原平行瞬时上调。肌成纤维细胞参与赖氨酰氧化酶的表达，该酶可能以前酶和活化酶的形式分泌。
