Related Experiment Video
Updated: May 3, 2026
09:37
A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation
Published on: March 15, 2018
13.0K
Microgravity control of autophagy modulates osteoclastogenesis
Yuvaraj Sambandam1, Molly T Townsend1, Jason J Pierce1
1Charles P. Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC, USA.
Bone
|January 28, 2014
Summary
Microgravity (μXg) accelerates bone loss by increasing osteoclast differentiation, a process linked to enhanced autophagy. Inhibiting autophagy may prevent this spaceflight-induced bone loss.
Area of Science:
- Space biology
- Cell biology
- Bone physiology
Background:
- Astronauts experience significant bone loss during space missions.
- Microgravity (μXg) is a key factor contributing to this bone loss.
- Autophagy, a cellular recycling process, is hypothesized to modulate osteoclastogenesis under μXg.
Purpose of the Study:
- To investigate the role of autophagy in microgravity-induced osteoclast differentiation.
- To determine if autophagy modulation can prevent bone loss in simulated spaceflight conditions.
Main Methods:
- Simulated microgravity (μXg) using Rotary Cell Culture System (RCCS).
- Real-time PCR and Western blot to analyze autophagic markers (Atg5, LC3).
- Confocal microscopy for autophagosome formation and RT2 profiler PCR array for autophagy-related genes.
- Treatment with autophagy inhibitor 3-methyladenine (3-MA) and RANK ligand (RANKL).
Main Results:
- μXg significantly increased autophagic markers (Atg5, LC3, Atg16L mRNA) and autophagosome formation in preosteoclast cells.
- μXg upregulated autophagy-related genes, signaling molecules, and inflammatory factors.
- 3-MA treatment reduced μXg-induced autophagic gene expression and suppressed osteoclast differentiation.
- 3-MA inhibited RANKL-induced p-CREB expression under μXg.
Conclusions:
- Microgravity-induced autophagy enhances osteoclast differentiation.
- Autophagy plays a critical role in spaceflight-associated bone loss.
- Targeting autophagy presents a potential therapeutic strategy to mitigate bone loss in astronauts.
Related Concept Videos
01:31Osteoclasts in Bone Remodeling
3.9K
Osteoclasts are cells responsible for bone resorption and remodeling. They originate from hematopoietic progenitor cells present in the bone marrow. Numerous progenitor cells fuse to form multinucleated cells, each with 10-20 nuclei. A single osteoclast has a diameter of 150 to 200 µM. These cells have ruffled borders that break down the underlying bone tissue and release minerals such as calcium into the blood in bone resorption. Osteoclasts cling to bones with their ruffled edges during...
3.9K
01:27Autophagy
5.0K
Autophagy is a self-digesting process by which a cell protects itself from threats both within and outside the cell, ranging from abnormal proteins to invading bacteria. In this process, obsolete components of the cell and invading microbes are degraded by hydrolytic enzymes active in an acidic environment of the lysosomal lumen.
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
5.0K
01:18Autophagic Cell Death
3.3K
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
3.3K
01:40Bone Remodeling
34.4K
Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain bone mass and calcium homeostasis. While mechanical stress can stimulate turnover as part of the normal maintenance and reparative process, several hormones also regulate bone remodeling.
34.4K
01:36Delivery Pathways to the Lysosome
7.6K
Eukaryotic cells use different mechanisms to eliminate toxic waste obsolete and worn-out substances. Lysosomes play a pivotal role in this, and hence, these substances are carried to the lysosome from other parts of the cell and extracellular space through different pathways. The most elaborately studied pathways to the lysosome are the endocytic pathways.
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
7.6K
01:22Cellular Injury V: Apoptosis and Autophagy
99
Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...
99