Determination of secretory granule maturation times in pancreatic islet β-cells by serial block-face electron microscopy.
Determination of secretory granule maturation times in pancreatic islet β-cells by serial block-face electron microscopy.
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DOI：
10.1016/j.jsb.2020.107584
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发表时间：
2020-10-01
影响因子：
3
通讯作者：
Leapman RD
中科院分区：
文献类型：
--
作者：
Rao A;McBride EL;Zhang G;Xu H;Cai T;Notkins AL;Aronova MA;Leapman RD
它显示了如何连续块面电子显微镜（SBEM）的胰岛素分泌β-细胞在野生型小鼠胰岛胰岛可以用来确定成熟时间的分泌颗粒。尽管SBEM及时捕捉到了β细胞结构的快照，但观察到的超微结构可被认为代表了细胞的动态平衡状态，因为胰岛在培养物中保持近似稳态。发现7.2±1.2%（±st. dev.）β-细胞体积的10%由分泌颗粒致密核心组成，其显示出被宽的（典型地约100 nm）电子透明晕包围的角形形状。这些细胞器被鉴定为储存胰岛素以通过质膜调节释放的成熟颗粒，释放时间为96±12小时，如先前通过半胱氨酸和蛋氨酸的脉冲35 S放射性标记获得的。β-细胞3D体积的分析揭示了一个没有电子透明晕的分泌细胞器亚群，被鉴定为未成熟的分泌颗粒。分泌颗粒的另一个亚群被发现具有薄的（通常为约30 nm）电子透明晕，这归因于通过激素原转化酶的作用从胰岛素原转化为胰岛素的未成熟颗粒。根据未成熟颗粒中胰岛素原与成熟颗粒中胰岛素的体积比，我们估计新形成的未成熟颗粒保持形态学定义的未成熟状态的平均时间为135±14分钟，未成熟转化颗粒保持形态学定义的未成熟状态的平均时间为130±17分钟。
It is shown how serial block-face electron microscopy (SBEM) of insulin-secreting β-cells in wild-type mouse pancreatic islets of Langerhans can be used to determine maturation times of secretory granules. Although SBEM captures the β-cell structure at a snapshot in time, the observed ultrastructure can be considered representative of a dynamic equilibrium state of the cells since the pancreatic islets are maintained in culture in approximate homeostasis. It was found that 7.2±1.2% (±st. dev.) of the β-cell volume is composed of secretory granule dense-cores exhibiting angular shapes surrounded by wide (typically ≳100 nm) electron-lucent halos. These organelles are identified as mature granules that store insulin for regulated release through the plasma membrane, with a release time of 96±12 hours, as previously obtained from pulsed 35S-radiolabeling of cysteine and methionine. Analysis of β-cell 3D volumes reveals a subpopulation of secretory organelles without electron-lucent halos, identified as immature secretory granules. Another subpopulation of secretory granules is found with thin (typically ≲30 nm) electron-lucent halos, which are attributed to immature granules that are transforming from proinsulin to insulin by action of prohormone convertases. From the volume ratio of proinsulin in the immature granules to insulin in the mature granules, we estimate that the newly formed immature granules remain in morphologically-defined immature states for an average time of 135±14 minutes, and the immature transforming granules for an average time of 130±17 minutes.
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影响因子：
4.6
作者：
He, Q.;Hsueh, M.;Leapman, R. D.
通讯作者：
Leapman, R. D.
影响因子：
--
作者：
Hou, June Chunqiu;Min, Le;Pessin, Jeffrey E.
通讯作者：
Pessin, Jeffrey E.
DOI：
10.1073/pnas.88.2.622
发表时间：
1991-01-01
影响因子：
11.1
作者：
BADGER, J;CASPAR, DLD
通讯作者：
CASPAR, DLD
DOI：
10.1007/978-1-62703-137-0_16
发表时间：
2013-01-01
期刊：
Methods in molecular biology (Clifton, N.J.)
影响因子：
--
作者：
Drobne, Damjana
通讯作者：
Drobne, Damjana
影响因子：
7.7
作者：
Declercq, Jeroen;Kumar, Anujith;Verfaillie, Catherine M.
通讯作者：
Verfaillie, Catherine M.