α1AMPK deletion in myelomonocytic cells induces a pro-inflammatory phenotype and enhances angiotensin II-induced vascular dysfunction.

Aims: Immune cell function involves energy-dependent processes including growth, proliferation, and cytokine production. Since the AMP-activated protein kinase (AMPK) is a crucial regulator of intracellular energy homeostasis, its expression and activity may also affect innate and adaptive immune cell responses. Therefore, we aimed to investigate the consequences of α1AMPK deletion in myelomonocytic cells on vascular function, inflammation, and hypertension during chronic angiotensin II (ATII) treatment. Methods and results: We generated a mouse strain with α1AMPK deletion in lysozyme M+ myelomonocytic cells. Compared to controls, chronic ATII infusion (1 mg/kg/day for 7 days) lead to increased vascular oxidative stress and aggravated endothelial dysfunction in LysM-Cre+ x α1AMPKfl/fl mice. This was accompanied by an increased aortic infiltration of CD11b+F4/80+ macrophages and enhanced pro-inflammatory cytokine release (tumour necrosis factor-alpha, interferon-gamma, and interleukin-6). Mechanistically, we found that increased expression of C-C chemokine receptor 2 (CCR2) in α1AMPK deficient myelomonocytic cells facilitated their recruitment to the vascular wall. In addition, expression of the ATII receptor type 1a and the oxidative burst was increased in these cells, indicating an increased susceptibility towards pro-oxidant stimuli. Conclusions: In summary, α1AMPK deletion in myelomonocytic cells aggravates vascular oxidative stress and dysfunction by enhancing their recruitment to the vascular wall and increasing their susceptibility towards pro-oxidant stimuli. Our observations suggest that metabolic control in myelomonocytic cells has profound implications for their inflammatory phenotype and may trigger the development of vascular disease.