AT2 Receptor Stimulation Inhibits Vascular Smooth Muscle Cell Senescence Induced by Angiotensin II and Hyperglycemia

Area of Science:

• Vascular Biology
• Cellular Senescence
• Endocrinology

Background:

• Hyperglycemia is a known inducer of vascular senescence.
• Angiotensin II (Ang II) promotes vascular smooth muscle cell (VSMC) senescence, with AT2 receptor deletion enhancing this effect.
• The interplay between Ang II and hyperglycemia in VSMC senescence requires further investigation.

Purpose of the Study:

• To investigate the synergistic effects of Ang II and hyperglycemia on VSMC senescence.
• To determine the role of the AT2 receptor agonist, compound 21 (C21), in modulating Ang II and hyperglycemia-induced VSMC senescence.

Main Methods:

• Aortic VSMCs were isolated from male mice.
• Cells were treated with Ang II, high glucose (Glu), C21, and modulators of autophagy (3-MA, rapamycin).
• Evaluated senescence, oxidative stress (superoxide anion), and protein expression (p21, pRb, LC3B II/I).

Main Results:

• Combined Ang II and Glu synergistically increased VSMC senescence and oxidative stress.
• C21 treatment significantly attenuated the senescence and oxidative stress induced by combined Ang II and Glu.
• Autophagy modulation influenced senescence, with C21 providing further inhibition.

Conclusions:

• Ang II and hyperglycemia synergistically promote VSMC senescence.
• This process involves autophagy, oxidative stress, and the p21-pRb pathway.
• C21 demonstrates inhibitory effects on Ang II and hyperglycemia-induced VSMC senescence.