Related Experiment Video
Updated: Jul 31, 2026
An In Vitro Model for the Study of Cellular Pathophysiology in Globoid Cell Leukodystrophy
Published on: October 21, 2014
Lipid-nanoparticle-induced vacuolization in microglia
Hubert H Kerschbaum1,2, Christopher Gerner3, Karin Oberascher4
1Department of Biosciences and Medical Biology, University of Salzburg, Salzburg, Austria. hubert.kerschbaum@plus.ac.at.
Abstract:
Lipid-containing vacuoles in microglia were discovered more than one hundred years ago in the brain of patients showing neurodegenerative processes. Recently, molecular-biological studies demonstrated specific changes in lipid-metabolism related to neurodegeneration. Despite that already Alzheimer described a distinct glia phenotype having large, lipid-containing vacuoles (Gitterzellen), little is known about how microglia convert lipid metabolites into a vacuolated phenotype. We studied the impact of liver-derived, insoluble, lipid-enriched nanoparticles (Lef-NP) ( ~ 20 nm) and of ceramide-coated Percoll-nanoparticles (Cer-NP) ( ~ 20 nm) on vacuolization in microglia. Lipidomic analysis of Lef-NP revealed numerous distinct lipids, including pro-inflammatory ceramides, which are enriched in the brain of Alzheimer patients. Video microscopy revealed that hepatocyte-derived Lef-NP and Cer-NP enhanced macropinocytosis, followed by macropinosome swelling and formation of the Gitterzellen phenotype. Neither ceramide nor Percoll-nanoparticles induced Gitterzellen-formation. Electron-tomography visualized membrane contact-sites between nanoparticle-loaded endosomes, endoplasmic reticulum cisternae and mitochondria. Suppression of lipid-nanoparticle-induced Gitterzellen-formation by amiloride, which supresses macropinocytosis, and bafilomycin A, an endosomal acidification inhibitor, further confirmed a pinocytotic pathway in Gitterzellen-formation. Bafilomycin A also reversed Gitterzellen to a ramified microglia phenotype. Our experimental findings suggest that lipid-nanoparticles but not emulsified lipids provoke vacuolization in microglia, and provide a simple in-vitro model for a pathogenic process taking years in the human brain.
Insights
Lipid nanoparticles trigger microglia vacuolization, forming Gitterzellen. This study models a key process in neurodegeneration, offering insights into Alzheimer's disease pathogenesis.
Area of Science:
- Neuroscience
- Cell Biology
- Lipid Metabolism
Background:
- Microglia, the brain's immune cells, exhibit lipid-containing vacuoles (Gitterzellen) in neurodegenerative diseases.
- The precise mechanisms by which microglia internalize and process lipids to form these vacuoles remain unclear.
- Alzheimer's disease pathology is associated with altered lipid metabolism and specific microglial phenotypes.
Purpose of the Study:
- To investigate how liver-derived lipid-enriched nanoparticles (Lef-NP) and ceramide-coated nanoparticles (Cer-NP) induce vacuolization in microglia.
- To elucidate the cellular pathways involved in nanoparticle-induced Gitterzellen formation.
- To establish an in vitro model for studying a pathogenic process relevant to neurodegeneration.
Main Methods:
- Utilized liver-derived lipid-enriched nanoparticles (Lef-NP) and ceramide-coated Percoll nanoparticles (Cer-NP) for in vitro studies.
- Employed video microscopy to observe cellular dynamics and macropinocytosis.
- Applied electron tomography to visualize ultrastructural changes and membrane contact sites.
- Used pharmacological inhibitors (amiloride, bafilomycin A) to probe the underlying cellular mechanisms.
Main Results:
- Lef-NP and Cer-NP significantly enhanced macropinocytosis and induced Gitterzellen formation in microglia.
- Neither ceramide nor Percoll nanoparticles alone caused Gitterzellen formation, indicating the importance of the lipid-nanoparticle structure.
- Electron tomography revealed membrane contact sites between endosomes, ER, and mitochondria during vacuolization.
- Inhibitors of macropinocytosis and endosomal acidification blocked Gitterzellen formation, confirming a pinocytotic pathway.
Conclusions:
- Lipid nanoparticles, but not emulsified lipids, provoke microglia vacuolization and the Gitterzellen phenotype.
- The study provides a novel in vitro model for understanding Gitterzellen formation, a process implicated in neurodegeneration.
- Findings suggest a potential link between nanoparticle uptake and pathological changes observed in Alzheimer's disease.
