Related Experiment Video
Updated: Jul 2, 2025
Molecular Modulation by Lentivirus-Delivered Specific shRNAs in Endoplasmic Reticulum Stressed Neurons
Published on: April 24, 2021
Modulating Golgi Stress Signaling Ameliorates Cell Morphological Phenotypes Induced by CHMP2B with Frontotemporal
Shoya Fukatsu1, Maho Okawa1, Miyu Okabe1
1Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan.
Abstract:
Some charged multivesicular body protein 2B (CHMP2B) mutations are associated with autosomal-dominant neurodegenerative frontotemporal dementia and/or amyotrophic lateral sclerosis type 7 (FTDALS7). The main aim of this study is to clarify the relationship between the expression of mutated CHMP2B protein displaying FTD symptoms and defective neuronal differentiation. First, we illustrate that the expression of CHMP2B with the Asp148Tyr (D148Y) mutation, which preferentially displays FTD phenotypes, blunts neurite process elongation in rat primary cortical neurons. Similar results were observed in the N1E-115 cell line, a model that undergoes neurite elongation. Second, these effects were also accompanied by changes in neuronal differentiation marker protein expression. Third, wild-type CHMP2B protein was indeed localized in the endosomal sorting complexes required to transport (ESCRT)-like structures throughout the cytoplasm. In contrast, CHMP2B with the D148Y mutation exhibited aggregation-like structures and accumulated in the Golgi body. Fourth, among currently known Golgi stress regulators, the expression levels of Hsp47, which has protective effects on the Golgi body, were decreased in cells expressing CHMP2B with the D148Y mutation. Fifth, Arf4, another Golgi stress-signaling molecule, was increased in mutant-expressing cells. Finally, when transfecting Hsp47 or knocking down Arf4 with small interfering (si)RNA, cellular phenotypes in mutant-expressing cells were recovered. These results suggest that CHMP2B with the D148Y mutation, acting through Golgi stress signaling, is negatively involved in the regulation of neuronal cell morphological differentiation, providing evidence that a molecule controlling Golgi stress may be one of the potential FTD therapeutic targets at the molecular and cellular levels.
Insights
Mutated CHMP2B protein impairs neuronal differentiation by disrupting Golgi stress signaling, suggesting Golgi stress regulators as potential therapeutic targets for frontotemporal dementia (FTD).
Area of Science:
- Neuroscience
- Cell Biology
- Genetics
Background:
- Charged multivesicular body protein 2B (CHMP2B) mutations are linked to frontotemporal dementia and/or amyotrophic lateral sclerosis type 7 (FTDALS7).
- Understanding the molecular mechanisms underlying CHMP2B-associated neurodegeneration is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the impact of mutated CHMP2B on neuronal differentiation.
- To elucidate the role of Golgi stress signaling in CHMP2B-induced cellular dysfunction.
Main Methods:
- Utilized rat primary cortical neurons and N1E-115 cell lines to study CHMP2B mutations.
- Analyzed neurite elongation, neuronal differentiation markers, protein localization (ESCRT, Golgi), and Golgi stress regulators (Hsp47, Arf4).
- Employed gene transfection and small interfering RNA (siRNA) to modulate Hsp47 and Arf4 levels.
Main Results:
- CHMP2B Asp148Tyr (D148Y) mutation blunted neurite elongation and altered differentiation markers.
- Mutant CHMP2B accumulated in the Golgi body, unlike wild-type protein in ESCRT structures.
- Golgi stress regulators Hsp47 and Arf4 levels were altered in mutant-expressing cells.
- Modulating Hsp47 or Arf4 expression rescued cellular phenotypes.
Conclusions:
- CHMP2B D148Y mutation negatively impacts neuronal differentiation via Golgi stress signaling.
- Aberrant Golgi stress regulation is implicated in FTD pathogenesis.
- Molecules controlling Golgi stress represent potential therapeutic targets for FTD.
