Unsaturated mannuronate oligosaccharide ameliorates β-amyloid pathology through autophagy in Alzheimer's disease cell...

Area of Science:

• Biochemistry
• Neuroscience
• Pharmacology

Background:

• Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by amyloid-beta (Aβ) plaque formation.
• Current therapeutic strategies for AD are limited, necessitating the exploration of novel treatments.

Purpose of the Study:

• To investigate the therapeutic potential of unsaturated mannuronate oligosaccharide (MOS) on Alzheimer's disease (AD).
• To elucidate the molecular mechanisms underlying MOS's effects on AD pathology, including Aβ aggregation and autophagy.

Main Methods:

• Enzymatic depolymerization of alginate-derived polymannuronate (PM) to obtain MOS (M2-M11).
• In vitro studies using N2a-sw cells and 3×Tg-AD primary cortex neurons.
• Analysis of Aβ aggregation, expression levels of Aβ, amyloid precursor protein (APP), and BACE1.
• Investigation of autophagy pathway modulation, including mTOR signaling and autophagosome-lysosome fusion.

Main Results:

• MOS significantly inhibited amyloid-beta (Aβ)_1-42 oligomer aggregation.
• MOS decreased Aβ_1-42 expression and reduced levels of amyloid precursor protein (APP) and BACE1.
• MOS promoted autophagy via inactivation of the mTOR signaling pathway and enhanced autophagosome-lysosome fusion.
• Autophagy inhibitors abrogated the anti-AD effects of MOS, confirming autophagy's crucial role.

Conclusions:

• Unsaturated mannuronate oligosaccharide (MOS) demonstrates significant therapeutic potential for Alzheimer's disease (AD).
• MOS exerts its anti-AD effects by inhibiting Aβ aggregation and promoting autophagy.
• MOS derived from seaweed alginate represents a promising candidate for nutraceutical or natural medicine interventions for AD.