| 1. |
- Gu, Hui, 1988, et al.
(author)
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Amperometry and Electron Microscopy show Stress Granules Induce Homotypic Fusion of Catecholamine Vesicles
- 2024
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In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION. - 1433-7851 .- 1521-3773. ; 63:16
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Journal article (peer-reviewed)abstract
- An overreactive stress granule (SG) pathway and long-lived, stable SGs formation are thought to participate in the progress of neurodegenerative diseases (NDs). To understand if and how SGs contribute to disorders of neurotransmitter release in NDs, we examined the interaction between extracellular isolated SGs and vesicles. Amperometry shows that the vesicular content increases and dynamics of vesicle opening slow down after vesicles are treated with SGs, suggesting larger vesicles are formed. Data from transmission electron microscopy (TEM) clearly shows that a portion of large dense-core vesicles (LDCVs) with double/multiple cores appear, thus confirming that SGs induce homotypic fusion between LDCVs. This might be a protective step to help cells to survive following high oxidative stress. A hypothetical mechanism is proposed whereby enriched mRNA or protein in the shell of SGs is likely to bind intrinsically disordered protein (IDP) regions of vesicle associated membrane protein (VAMP) driving a disrupted membrane between two closely buddled vesicles to fuse with each other to form double-core vesicles. Our results show that SGs induce homotypic fusion of LDCVs, providing better understanding of how SGs intervene in pathological processes and opening a new direction to investigations of SGs involved neurodegenerative disease. Vesicle impact electrochemical cytometry (VIEC) reveals larger molecule number and slower dynamics of vesicles opening after vesicles are treated with stress granules (SGs), implying homotypic fusion between vesicles, confirmed by observation of multi-core vesicles with transmission electron microscopy (TEM). This finding provides new insights into how neural cells regulate exocytosis under oxidative stress and how SGs promote neurodegeneration.
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| 2. |
- Rabasco, Stefania, et al.
(author)
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Characterization of Stress Granule Protein Turnover in Neuronal Progenitor Cells Using Correlative STED and NanoSIMS Imaging
- 2023
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 24
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Journal article (peer-reviewed)abstract
- Stress granules (SGs) are stress-induced biomolecular condensates which originate primarily from inactivated RNA translation machinery and translation initiation factors. SG formation is an important defensive mechanism for cell survival, while its dysfunction has been linked to neurodegenerative diseases. However, the molecular mechanisms of SG assembly and disassembly, as well as their impacts on cellular recovery, are not fully understood. More thorough investigations into the molecular dynamics of SG pathways are required to understand the pathophysiological roles of SGs in cellular systems. Here, we characterize the SG and cytoplasmic protein turnover in neuronal progenitor cells (NPCs) under stressed and non-stressed conditions using correlative STED and NanoSIMS imaging. We incubate NPCs with isotopically labelled (15N) leucine and stress them with the ER stressor thapsigargin (TG). A correlation of STED and NanoSIMS allows the localization of individual SGs (using STED), and their protein turnover can then be extracted based on the 15N/14N ratio (using NanoSIMS). We found that TG-induced SGs, which are highly dynamic domains, recruit their constituents predominantly from the cytoplasm. Moreover, ER stress impairs the total cellular protein turnover regimen, and this impairment is not restored after the commonly proceeded stress recovery period.
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