The intracellular domain of cell adhesion molecule 1 is present in emphysematous lungs and induces lung epithelial cell apoptosis.
The intracellular domain of cell adhesion molecule 1 is present in emphysematous lungs and induces lung epithelial cell apoptosis.
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DOI：
10.1186/s12929-015-0173-8
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发表时间：
2015-08-11
影响因子：
11
通讯作者：
Ito A
中科院分区：
文献类型：
--
作者：
Hagiyama M;Yoneshige A;Inoue T;Sato Y;Mimae T;Okada M;Ito A
肺气肿在组织学上的特征是由于肺上皮细胞凋亡导致肺泡壁的破坏和空气空间的扩大。细胞粘附分子1（CADM 1）是在肺上皮细胞中表达的免疫球蛋白超家族成员。CADM 1通过A去整合素和金属蛋白酶-10介导的胞外域脱落产生膜相关C末端片段αCTF，随后通过γ-分泌酶介导的αCTF膜内脱落释放胞内结构域（ICD）。αCTF定位于线粒体并诱导肺上皮细胞凋亡。由于CADM 1胞外域脱落增加，αCTF有助于肺气肿的发生和进展。本研究的目的是检查ICD是否做出了类似的贡献。ICD被合成为51个氨基酸的肽，并且其突变体通过取代7个氨基酸和缺失2个氨基酸来合成。用异硫氰酸荧光素标记这些肽，并将其引入各种细胞系中。ICD肽衍生的荧光在肺上皮细胞中在Mitotracker线粒体标记的位点处很好地可视化，但在其他细胞类型中在线粒体以外的位置处检测到。在线粒体以外的位置，甚至在肺上皮细胞中检测到突变肽衍生的荧光。末端脱氧核苷酸转移酶介导的dUTP缺口末端标记试验表明，ICD肽的转导增加了肺上皮细胞系中凋亡细胞的比例2至5倍，而突变肽没有。在肺气肿（n = 4）和对照（n = 4）人肺中，ICD的ABBYY低于Western印迹检测限。然而，当用抗CADM 1抗体进行免疫沉淀时，仅在肺气肿肺中检测到ICD（4/4 vs. 0/4，P = 0.029）。由于ICD分子的丰度稀少但存在，增加的CADM 1脱落似乎通过在肺上皮细胞中产生αCTF和ICD而促进肺气肿的发展。本文的在线版本（doi：10.1186/s12929-015-0173-8）包含补充材料，可供授权用户使用。
Pulmonary emphysema is characterized histologically by destruction of alveolar walls and enlargement of air spaces due to lung epithelial cell apoptosis. Cell adhesion molecule 1 (CADM1) is an immunoglobulin superfamily member expressed in lung epithelial cells. CADM1 generates a membrane-associated C-terminal fragment, αCTF, through A disintegrin- and metalloprotease-10-mediated ectodomain shedding, subsequently releasing the intracellular domain (ICD) through γ-secretase-mediated intramembrane shedding of αCTF. αCTF localizes to mitochondria and induces apoptosis in lung epithelial cells. αCTF contributes to the development and progression of emphysema as a consequence of increased CADM1 ectodomain shedding. The purpose of this study was to examine whether the ICD makes a similar contribution. The ICD was synthesized as a 51-amino acid peptide, and its mutant was synthesized by substituting seven amino acids and deleting two amino acids. These peptides were labeled with fluorescein isothiocyanate and were introduced into various cell lines. ICD peptide-derived fluorescence was well visualized in lung epithelial cells at the site of Mitotracker mitochondrial labeling, but was detected in locations other than mitochondria in other cell types. Mutant peptide-derived fluorescence was detected in locations other than mitochondria, even in lung epithelial cells. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays revealed that transduction of the ICD peptide increased the proportion of apoptotic cells 2- to 5-fold in the lung epithelial cell lines, whereas the mutant peptide did not. Abundance of the ICD was below the Western blot detection limit in emphysematous (n = 4) and control (n = 4) human lungs. However, the ICD was detected only in emphysematous lungs when it was immunoprecipitated with anti-CADM1 antibody (4/4 vs. 0/4, P = 0.029). As the abundance of ICD molecules was sparse but present, increased CADM1 shedding appeared to contribute to the development of emphysema by generating αCTF and the ICD in lung epithelial cells. The online version of this article (doi:10.1186/s12929-015-0173-8) contains supplementary material, which is available to authorized users.