Impaired NH2-terminal processing of human proislet amyloid polypeptide by the prohormone convertase PC2 leads to amyloid formation and cell death
Impaired NH2-terminal processing of human proislet amyloid polypeptide by the prohormone convertase PC2 leads to amyloid formation and cell death
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DOI：
10.2337/db05-1566
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发表时间：
2006-08-01
期刊：
影响因子：
7.7
通讯作者：
Verchere, C. Bruce
中科院分区：
文献类型：
--
作者：
Marzban, Lucy;Rhodes, Christopher J.;Verchere, C. Bruce
由胰岛淀粉样多肽（LAPP;胰淀素）聚集形成的胰岛淀粉样蛋白是2型糖尿病中胰腺的病理特征，并且可能导致该疾病中β细胞的进行性损失。我们检验了LAPP前体proIAPP加工受损导致淀粉样蛋白形成和细胞死亡的假设。用表达与绿色荧光蛋白连接的人或大鼠（对照）proIAPP的腺病毒（Ad）转导缺乏激素原转化酶1/3（PC 1/3）和LAPP且具有非常低水平的激素原转化酶2（PC 2）的GH 3细胞，有或没有Ad-PC 2或Ad-PC 1/3。在转导后96小时，人proIAPP的表达增加了转移酶介导的dUTP缺口末端标记（TUNEL）阳性细胞的数量（+hIAPP 8.7 +/- 0.4%对对照3.0 +/- 0.4%; P < 0.05）。通过PC 1/3的人proIAPP的COOH末端加工增加（hIAPP+ PC 1/3 10.4 +/- 0.7%; P < 0.05），而通过加入PC 2的proIAPP的NH 2末端加工显著减少（hIAPP+ PC 2 5.5 +/- 0.5%; P < 0.05）凋亡的GH 3细胞的数目。来自缺乏PC 2且β细胞表达人proIAPP（hIAPP（+/+）/PC 2（-/-））的小鼠的胰岛在2周培养期间产生与β细胞死亡相关的淀粉样蛋白。通过用Ad-PC 2离体转导拯救PC 2表达恢复了NH 2-末端加工成成熟LAPP，并降低了淀粉样蛋白形成的程度和TUNEL阳性细胞的数量（-PC 2 26.5 +/- 4.1%对+PC 2 16.1 +/- 4.3%; P < 0.05）。这些发现表明，受损的NH 2-末端加工的proIAPP导致淀粉样蛋白的形成和细胞死亡，NH 2-末端延伸的人proIAPP中间体的积累可能是淀粉样蛋白形成的关键起始步骤。
Islet amyloid, formed by aggregation of islet amyloid polypeptide (LAPP; amylin), is a pathological characteristic of the pancreas in type 2 diabetes and may contribute to the progressive loss of beta-cells in this disease. We tested the hypothesis that impaired processing of the LAPP precursor proIAPP contributes to amyloid formation and cell death. GH3 cells lacking the prohormone convertase 1/3 (PC1/3) and LAPP and with very low levels of prohormone convertase 2 (PC2) were transduced with adenovirus (Ad) expressing human or rat (control) proIAPP linked to green fluorescent protein, with or without Ad-PC2 or Ad-PC1/3. Expression of human proIAPP increased the number of transferase-mediated dUTP nick-end labeling (TUNEL)positive cells 96 h after transduction (+hIAPP 8.7 +/- 0.4% vs. control 3.0 +/- 0.4%; P < 0.05). COOH-terminal processing of human proIAPP by PC1/3 increased (hIAPP+PC1/3 10.4 +/- 0.7%; P < 0.05), whereas NH2-terminal processing of proIAPP by addition of PC2 markedly decreased (hIAPP+PC2 5.5 +/- 0.5%; P < 0.05) the number of apoptotic GH3 cells. Islets from mice lacking PC2 and with beta-cell expression of human proIAPP (hIAPP(+/+)/PC2(-/-)) developed amyloid associated with beta-cell death during 2-week culture. Rescue of PC2 expression by ex vivo transduction with Ad-PC2 restored NH2-terminal processing to mature LAPP and decreased both the extent of amyloid formation and the number of TUNEL-positive cells (-PC2 26.5 +/- 4.1% vs. +PC2 16.1 +/- 4.3%; P < 0.05). These findings suggest that impaired NH2-terminal processing of proIAPP leads to amyloid formation and cell death and that accumulation of the NH2-terminally extended human proIAPP intermediate may be a critical initiating step in amyloid formation.