White Matter and Neuroprotection in Alzheimer's Dementia.

Alessandro Giuliani,Andrea Bighinati,Luca Lorenzini,Laura Calzà,Luciana Giardino,Mercedes Fernandez,Vito Antonio Baldassarro

doi:10.3390/molecules25030503

Alessandro Giuliani, Andrea Bighinati + Show 5 more

Open Access

https://doi.org/10.3390/molecules25030503

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Abstract

Myelin is the main component of the white matter of the central nervous system (CNS), allowing the proper electrical function of the neurons by ensheathing and insulating the axons. The extensive use of magnetic resonance imaging has highlighted the white matter alterations in Alzheimer’s dementia (AD) and other neurodegenerative diseases, alterations which are early, extended, and regionally selective. Given that the white matter turnover is considerable in the adulthood, and that myelin repair is currently recognized as being the only true reparative capability of the mature CNS, oligodendrocyte precursor cells (OPCs), the cells that differentiate in oligodendrocyte, responsible for myelin formation and repair, are regarded as a potential target for neuroprotection. In this review, several aspects of the OPC biology are reviewed. The histology and functional role of OPCs in the neurovascular-neuroglial unit as described in preclinical and clinical studies on AD is discussed, such as the OPC vulnerability to hypoxia-ischemia, neuroinflammation, and amyloid deposition. Finally, the position of OPCs in drug discovery strategies for dementia is discussed.

Highlights

Myelin is the main component of the white matter of the central nervous system (CNS), allowing the proper electrical function of the neurons by ensheathing and insulating the axons
Alzheimer’s dementia (AD) has classically been associated with a pathological Grey Matter (GM) process, where extracellular neuritic plaques of amyloid-beta (Aβ) and intraneuronal aggregates of neurofibrillary tangles made of phosphorylated tau protein are considered the main cause of neurodegeneration
We have extensively studied the histopathology and neurochemistry of the preclinical phase of AD in the mouse model Tg2576, carrying the APP KM670/671NL (Swedish) modification, showing that (1) intraneuronal and intraglial Aβ accumulation precedes amyloid plaque deposition [31,32]; (2) intraneuronal Aβ accumulation increases neuronal vulnerability to oxygen-glucose deprivation (OGD) [33]; (3) a molecular dysfunction involving HIF signaling in the cerebral cortex, regarding the vascular endothelial growth factor receptor, is already present in

Summary

Introduction

“White matter” (WM) in the central nervous system (CNS) represents approximately 50% of brain mass [1]. These terms refer to the de novo myelination of previously unmyelinated axons, to myelin sheaths replacement, or to the myelin remodeling which occurs during a person’s lifetime, as a consequence of multiple environmental factors such as voluntary physical exercise, social enrichment, motor learning, and cognitive training [3,4,5]. This plasticity, together with the increasing knowledge of the cell types responsible for myelin dynamics, i.e., the oligodendrocyte precursor cell (OPC), has raised a number of questions regarding. These degenerative changes have not been associated with a high amyloid plaque burden [26,27], while other studies correlates WM pathology in preclinical AD with biomarkers in the cerebrospinal fluid [28]

OPCs and Mature Oligodendrocytes in Alzheimer’s Disease and Animal Models

OPC Vulnerability in Neurodegenerative Diseases

OPCs as Target for Neuroprotection

Conclusions

Findings

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