Aβ inhibits mesenchymal stem cell-pericyte transition through MAPK pathway

Area of Science:

• Neuroscience
• Cell Biology
• Vascular Biology

Background:

• Pericyte loss is a hallmark of human Alzheimer's disease (AD) in the brain's hippocampus and cortex.
• Pericyte differentiation and recruitment are vital for blood vessel development.
• The specific impact of amyloid beta (Aβ) on pericyte differentiation remains unclear.

Purpose of the Study:

• To investigate the interaction between Aβ and the differentiation of mesenchymal stem cells (MSCs) into pericytes.
• To elucidate the mechanisms by which Aβ affects pericyte differentiation.

Main Methods:

• Examined pericyte markers (desmin) in the cortex of APP/PS1 mice overexpressing Aβ.
• Assessed the effect of Aβ40 and Aβ42 on pericyte marker expression (α-SMA, desmin, PDGFRβ) in cultured MSCs.
• Investigated the role of the ERK1/2 MAPK signaling pathway in mediating Aβ's effects.

Main Results:

• APP/PS1 mice showed significant pericyte loss compared to controls, indicated by reduced desmin expression.
• Both Aβ40 and Aβ42 inhibited the expression of key pericyte markers in differentiating MSCs.
• Aβ-induced inhibition of MSC-to-pericyte transition was mediated by the activation of the ERK1/2 MAPK pathway.

Conclusions:

• Amyloid beta directly inhibits the differentiation of mesenchymal stem cells into pericytes.
• The ERK1/2 MAPK pathway is a key mediator of Aβ's detrimental effects on pericyte differentiation.
• Understanding Aβ's role in pericyte differentiation may offer new therapeutic targets for Alzheimer's disease.