Angiotensin II and Amyloid-β Synergistically Induce Brain Vascular Smooth Muscle Cell Senescence

Area of Science:

• Cardiovascular Biology
• Neuroscience
• Cellular Aging

Background:

• Amyloid-β (Aβ) is known to cause cerebrovascular damage and endothelial cell senescence.
• Previous research indicated that angiotensin II (Ang II) promotes vascular senescence.
• This study investigates the interaction between Ang II and Aβ in regulating brain vascular smooth muscle cell (BVSMC) senescence.

Purpose of the Study:

• To examine the synergistic effects of Ang II and Aβ on BVSMC senescence.
• To elucidate the molecular mechanisms underlying the cross-talk between Ang II and Aβ in promoting vascular senescence.

Main Methods:

• BVSMCs were isolated from mice and treated with varying concentrations of Ang II and/or Aβ.
• Cellular senescence was assessed using senescence-associated β-galactosidase staining.
• Key signaling pathways, including ERK, NF-κB, and related proteins, were analyzed.

Main Results:

• Combined lower doses of Ang II and Aβ significantly increased BVSMC senescence, unlike individual lower doses.
• This synergistic senescence was inhibited by Ang II receptor blocker (valsartan) and Aβ receptor TLR4 inhibitor (TAK-242).
• The combination treatment elevated superoxide anion levels, activated ERK and NF-κB pathways, and altered expression of senescence markers (p16, p53, pRb).

Conclusions:

• Ang II and Aβ synergistically promote BVSMC senescence.
• The mechanism involves enhanced oxidative stress, NF-κB/IκB activity, and the p-ERK-p16-pRb signaling pathway.
• Targeting these pathways may offer therapeutic strategies for cerebrovascular aging.