scholarly journals Endoplasmic reticulum mediates mitochondrial transfer within the osteocyte dendritic network

2019 ◽  
Vol 5 (11) ◽  
pp. eaaw7215 ◽  
Author(s):  
Junjie Gao ◽  
An Qin ◽  
Delin Liu ◽  
Rui Ruan ◽  
Qiyang Wang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Tissue Homeostasis ◽  
Confocal Imaging ◽  
Metabolic Function ◽  
Mitofusin 2 ◽  
Dendritic Network ◽  
Dendritic Networks ◽  
Mitochondrial Transfer ◽  
Mitochondrial Distribution

Mitochondrial transfer plays a crucial role in the regulation of tissue homeostasis and resistance to cancer chemotherapy. Osteocytes have interconnecting dendritic networks and are a model to investigate its mechanism. We have demonstrated, in primary murine osteocytes with photoactivatable mitochondria (PhAM)floxed and in MLO-Y4 cells, mitochondrial transfer in the dendritic networks visualized by high-resolution confocal imaging. Normal osteocytes transferred mitochondria to adjacent metabolically stressed osteocytes and restored their metabolic function. The coordinated movement and transfer of mitochondria within the dendritic network rely on contact between the endoplasmic reticulum (ER) and mitochondria. Mitofusin 2 (Mfn2), a GTPase that tethers ER to mitochondria, predominantly mediates the transfer. A decline in Mfn2 expression with age occurs concomitantly with both impaired mitochondrial distribution and transfer in the osteocyte dendritic network. These data show a previously unknown function of ER-mitochondrial contact in mediating mitochondrial transfer and provide a mechanism to explain the homeostasis of osteocytes.

The ultrastructure of the double membrane-bound bodies and endoplasmic reticulum in serial sections of wheat spot mosaic-affected wheat plants

1990 ◽  
Vol 48 (3) ◽  
pp. 694-695
Author(s):  
M. H. Chen ◽  
C. Hiruki
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Membrane Structure ◽  
Mosaic Disease ◽  
Serial Sections ◽  
Thin Sections ◽  
Double Membrane ◽  
Southern Alberta ◽  
Membrane Bound ◽  
Scanning Em

Wheat spot mosaic disease was first discovered in southern Alberta, Canada, in 1956. A hitherto unidentified disease-causing agent, transmitted by the eriophyid mite, caused chlorosis, stunting and finally severe necrosis resulting in the death of the affected plants. Double membrane-bound bodies (DMBB), 0.1-0.2 μm in diameter were found to be associated with the disease.Young tissues of leaf and root from 4-wk-old infected wheat plants were fixed, dehydrated, and embedded in Spurr’s resin. Serial sections were collected on slot copper grids and stained. The thin sections were then examined with a Hitachi H-7000 TEM at 75 kV. The membrane structure of the DMBBs was studied by numbering them individually and tracing along the sections to see any physical connection with endoplasmic reticulum (ER) membranes. For high resolution scanning EM, a modification of Tanaka’s method was used. The specimens were examined with a Hitachi Model S-570 SEM in its high resolution mode at 20 kV.

scholarly journals Mitofusin 2 (Mfn2) links mitochondrial and endoplasmic reticulum function with insulin signaling and is essential for normal glucose homeostasis

2012 ◽  
Vol 109 (14) ◽  
pp. 5523-5528 ◽  
Author(s):  
D. Sebastian ◽  
M. I. Hernandez-Alvarez ◽  
J. Segales ◽  
E. Sorianello ◽  
J. P. Munoz ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Glucose Homeostasis ◽  
Insulin Signaling ◽  
Mitofusin 2 ◽  
Normal Glucose

scholarly journals BS46 High content high resolution confocal imaging to characterise mutations in the apelin receptor identified in patients from the 100,000 genomes project

2019 ◽  
Author(s):  
Tom Williams ◽  
Elisabeth O’Flaherty ◽  
Duuamene Nyimanu ◽  
Robyn Macrae ◽  
Heather Currinn ◽  
...  
Keyword(s):  
High Resolution ◽  
Confocal Imaging ◽  
Apelin Receptor

scholarly journals Improved spatial resolution by induced live cell and organelle swelling in hypotonic solutions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Astha Jaiswal ◽  
Christian H. Hoerth ◽  
Ana M. Zúñiga Pereira ◽  
Holger Lorenz
Keyword(s):  
Endoplasmic Reticulum ◽  
Cost Effectiveness ◽  
High Resolution ◽  
Light Microscopy ◽  
Matrix Protein ◽  
Super Resolution ◽  
Ease Of Use ◽  
Live Cells ◽  
Cell Organelles ◽  
Morphology Changes

Abstract Induced morphology changes of cells and organelles are by far the easiest way to determine precise protein sub-locations and organelle quantities in light microscopy. By using hypotonic solutions to swell mammalian cell organelles we demonstrate that precise membrane, lumen or matrix protein locations within the endoplasmic reticulum, Golgi and mitochondria can reliably be established. We also show the benefit of this approach for organelle quantifications, especially for clumped or intertwined organelles like peroxisomes and mitochondria. Since cell and organelle swelling is reversible, it can be applied to live cells for successive high-resolution analyses. Our approach outperforms many existing imaging modalities with respect to resolution, ease-of-use and cost-effectiveness without excluding any co-utilization with existing optical (super)resolution techniques.

Saturated lipids decrease mitofusin 2 leading to endoplasmic reticulum stress activation and insulin resistance in hypothalamic cells

2015 ◽  
Vol 1627 ◽  
pp. 80-89 ◽  
Author(s):  
Brenda Diaz ◽  
Lizeth Fuentes-Mera ◽  
Armando Tovar ◽  
Teresa Montiel ◽  
Lourdes Massieu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Mitofusin 2 ◽  
Hypothalamic Cells ◽  
Stress Activation

scholarly journals Mitofusin-2: A New Mediator of Pathological Cell Proliferation

2021 ◽  
Vol 9 ◽  
Author(s):  
Yanguo Xin ◽  
Junli Li ◽  
Wenchao Wu ◽  
Xiaojing Liu
Keyword(s):  
Cell Proliferation ◽  
Potential Role ◽  
Mitochondrial Dynamics ◽  
Cell Types ◽  
Tissue Homeostasis ◽  
Mitochondrial Network ◽  
Biological Functions ◽  
Potential Therapeutic Target ◽  
Mitofusin 2 ◽  
Growing Body

Cell proliferation is an important cellular process for physiological tissue homeostasis and remodeling. The mechanisms of cell proliferation in response to pathological stresses are not fully understood. Mitochondria are highly dynamic organelles whose shape, number, and biological functions are modulated by mitochondrial dynamics, including fusion and fission. Mitofusin-2 (Mfn-2) is an essential GTPase-related mitochondrial dynamics protein for maintaining mitochondrial network and bioenergetics. A growing body of evidence indicates that Mfn-2 has a potential role in regulating cell proliferation in various cell types. Here we review these new functions of Mfn-2, highlighting its crucial role in several signaling pathways during the process of pathological cell proliferation. We conclude that Mfn-2 could be a new mediator of pathological cell proliferation and a potential therapeutic target.

scholarly journals Entangled architecture of rough endoplasmic reticulum (RER) and vacuoles enables topological damping in cytoplasm of an ultra-fast giant cell

2021 ◽  
Author(s):  
Ray Chang ◽  
Manu Prakash
Keyword(s):  
Endoplasmic Reticulum ◽  
Giant Cell ◽  
Rough Endoplasmic Reticulum ◽  
Volume Fraction ◽  
Single Cells ◽  
Cellular Systems ◽  
Confocal Imaging ◽  
Dynamics Simulation ◽  
Cellular Damage ◽  
Novel Association

Cellular systems are known to exhibit some of the fastest movements in the biological world - but little is known as to how single cells can dissipate this energy rapidly and adapt to such large accelerations without sub-cellular damage. To study intracellular adaptations under extreme forces - we investigate Spirostomum ambiguum - a giant cell (1-4mm in length) well known to exhibit ultrafast contractions (50% of body length) within 5 msec with a peak acceleration of 15g. Utilizing transmitted electron microscopy (TEM) and confocal imaging, we discover a novel association of rough endoplasmic reticulum (RER) and vacuoles throughout the cell - forming a contiguous fenestrated cubic membrane architecture that topologically entangles these two organelles. A nearly uniform inter-organelle spacing of 60nm is observed between RER and vacuoles, closely packing the entire cell. Using an overdamped molecular dynamics simulation, we demonstrate how this unique entangled metamaterial responds to external loads by rapidly dissipating energy and helps preserve spatial relationships between organelles. Because this dynamics arises primarily from entanglement of two networks incurring jamming transition at a subcritical volume fraction - we term this phenomena "topological damping". Our findings suggest a new mechanical role of RER-vacuolar meshwork as a metamaterial capable of dissipating energy in an ultra-fast contraction event.

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