Gene targeting of the cysteine peptidase cathepsin H impairs lung surfactant in mice.
Gene targeting of the cysteine peptidase cathepsin H impairs lung surfactant in mice.
复制标题
DOI：
10.1371/journal.pone.0026247
复制
发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Reinheckel T
中科院分区：
文献类型：
--
作者：
Bühling F;Kouadio M;Chwieralski CE;Kern U;Hohlfeld JM;Klemm N;Friedrichs N;Roth W;Deussing JM;Peters C;Reinheckel T
这11种人半胱氨酸组织蛋白是主要分布于所有细胞的内溶酶体和某些分泌细胞的胞吐途径内的蛋白水解酶。组织蛋白酶H(Ctsh)具有氨基和内肽酶活性。体外研究表明，Ctsh参与了肺表面活性物质蛋白B(SP-B)的加工和分泌。此外，Ctsh在肺泡II型肺泡细胞的分泌细胞器中高度表达，肺泡II型肺泡细胞是表面活性蛋白加工的地方。因此，我们在胚胎干细胞中通过基因打靶的方法产生了Ctsh缺失的小鼠，以研究这种蛋白水解酶在体内表面活性物质加工中的作用。靶向构建体包含一个能够使Ctsh表达位点可视化的ç-半乳糖苷酶(LacZ)报告。通过Northern印迹、Western印迹和Ctsh氨基肽酶活性测定，证实了Ctsh缺失。CTSH−/−小鼠无大体表型，发育正常，无生长迟缓。−/−小鼠支气管肺泡灌洗液中SP-B含量较低，表明SP-B分泌减少。CTSH+/+和CTSH−/−小鼠肺泡灌洗液中磷脂浓度无明显差异，但脉动气泡表面张力测定显示CTSH−/−小鼠肺表面活性物质的降压功能受损。我们的结论是，组织蛋白酶H参与了SP-B的产生，SP-B水平的降低损害了肺表面活性物质的物理性质。然而，Ctsh缺失并不能复制SP-B缺陷小鼠的严重表型。因此，II型肺泡细胞分泌途径的其他酶，即组织蛋白C或E，在缺乏Ctsh的情况下仍然能够产生足够质量的表面活性物质。
The 11 human cysteine cathepsins are proteases mainly located in the endolysosomal compartment of all cells and within the exocytosis pathways of some secretory cell types. Cathepsin H (Ctsh) has amino- and endopeptidase activities. In vitro studies have demonstrated Ctsh involvement in the processing and secretion of the pulmonary surfactant protein B (SP-B). Furthermore, Ctsh is highly expressed in the secretory organelles of alveolar type II pneumocytes where the surfactant proteins are processed. Hence, we generated Ctsh null mice by gene targeting in embryonic stem cells to investigate the role of this protease in surfactant processing in vivo. The targeting construct contains a ß-galactosidase (lacZ) reporter enabling the visualisation of Ctsh expression sites. Ctsh-deficiency was verified by northern blot, western blot, and measurement of the Ctsh aminopeptidase activity. Ctsh −/− mice show no gross phenotype and their development is normal without growth retardation. Broncho-alveolar lavage (BAL) from Ctsh −/− mice contained lower levels of SP-B indicating reduced SP-B secretion. The BAL phospholipid concentration was not different in Ctsh+/+ and Ctsh −/− mice, but measurement of surface tension by pulsating bubble surfactometry revealed an impairment of the tension reducing function of lung surfactant of Ctsh −/− mice. We conclude that cathepsin H is involved in the SP-B production and reduced SP-B levels impair the physical properties of the lung surfactant. However, Ctsh defiency does not reproduce the severe phenotype of SP-B deficient mice. Hence, other proteases of the secretory pathway of type II pneumocytes, i.e. cathepsins C or E, are still able to produce surfactant of sufficient quality in absence of Ctsh.
登录
查看更多内容
影响因子：
3.7
作者：
Gocheva V;Chen X;Peters C;Reinheckel T;Joyce JA
通讯作者：
Joyce JA
影响因子：
--
作者：
WEAVER, TE;LIN, S;DEY, C
通讯作者：
DEY, C
DOI：
10.1152/ajplung.1997.273.4.l875
发表时间：
1997-10-01
影响因子：
4.9
作者：
Tokieda, K;Whitsett, JA;Iwamoto, HS
通讯作者：
Iwamoto, HS
影响因子：
4.8
作者：
Ueno, T;Linder, S;Weaver, TE
通讯作者：
Weaver, TE
DOI：
10.1164/ajrccm.159.6.9806145
发表时间：
1999-06-01
影响因子：
24.7
作者：
Hohlfeld, JM;Ahlf, K;Krug, N
通讯作者：
Krug, N