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Updated: Oct 12, 2025
In Vitro Phagocytosis of Myelin Debris by Bone Marrow-Derived Macrophages
Published on: December 30, 2017
BASHY Dye Platform Enables the Fluorescence Bioimaging of Myelin Debris Phagocytosis by Microglia during
Maria V Pinto1, Fábio M F Santos1, Catarina Barros1
1Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal.
Abstract:
Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that is characterized by the presence of demyelinated regions with accumulated myelin lipid debris. Importantly, to allow effective remyelination, such debris must be cleared by microglia. Therefore, the study of microglial activity with sensitive tools is of great interest to better monitor the MS clinical course. Using a boronic acid-based (BASHY) fluorophore, specific for nonpolar lipid aggregates, we aimed to address BASHY's ability to label nonpolar myelin debris and image myelin clearance in the context of demyelination. Demyelinated ex vivo organotypic cultures (OCSCs) and primary microglia cells were immunostained to evaluate BASHY's co-localization with myelin debris and also to evaluate BASHY's specificity for phagocytosing cells. Additionally, mice induced with experimental autoimmune encephalomyelitis (EAE) were injected with BASHY and posteriorly analyzed to evaluate BASHY+ microglia within demyelinated lesions. Indeed, in our in vitro and ex vivo studies, we showed a significant increase in BASHY labeling in demyelinated OCSCs, mostly co-localized with Iba1-expressing amoeboid/phagocytic microglia. Most importantly, BASHY's presence was also found within demyelinated areas of EAE mice, essentially co-localizing with lesion-associated Iba1+ cells, evidencing BASHY's potential for the in vivo bioimaging of myelin clearance and myelin-carrying microglia in regions of active demyelination.
Insights
A new fluorophore, BASHY, effectively labels myelin debris in multiple sclerosis (MS) models. This tool images myelin clearance by microglia, aiding in monitoring disease activity and therapeutic responses.
Area of Science:
- Neuroscience
- Immunology
- Biochemistry
Background:
- Multiple sclerosis (MS) involves central nervous system demyelination and myelin debris accumulation.
- Microglia are crucial for clearing this debris to enable remyelination.
- Sensitive tools are needed to monitor microglial activity in MS.
Purpose of the Study:
- To evaluate a novel boronic acid-based (BASHY) fluorophore for labeling nonpolar myelin debris.
- To assess BASHY's capability in imaging myelin clearance by microglia in demyelination contexts.
- To determine BASHY's utility for in vivo bioimaging of microglial phagocytosis in MS models.
Main Methods:
- In vitro and ex vivo studies using organotypic cultures (OCSCs) and primary microglia.
- Immunostaining to assess BASHY co-localization with myelin debris and phagocytic microglia (Iba1+).
- In vivo studies using experimental autoimmune encephalomyelitis (EAE) mouse model injected with BASHY.
Main Results:
- BASHY significantly increased labeling in demyelinated OCSCs, co-localizing with phagocytic microglia.
- BASHY was detected in demyelinated areas of EAE mice, co-localizing with lesion-associated microglia.
- Demonstrated BASHY's specificity for nonpolar lipid aggregates and phagocytosing cells.
Conclusions:
- BASHY is a sensitive tool for detecting myelin debris in demyelinating conditions.
- BASHY enables in vivo bioimaging of myelin clearance by microglia.
- This fluorophore holds potential for monitoring MS progression and treatment efficacy.
