Induction of Atherosclerotic Plaques Through Activation of Mineralocorticoid Receptors in Apolipoprotein E-deficient Mice

Enhanced Local Delivery of microRNA-145a-5P into Mouse Aorta via Ultrasound-Targeted Microbubble Destruction Inhibits Atherosclerotic Plaque Formation

Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) play a key role in the formation and rupture of atherosclerotic plaques. Previous studies have confirmed that microRNA-145 (miR-145) is involved in the phenotypic regulation of VSMCs and reduction of atherosclerosis. At present, seeking safe and effective gene delivery remains a key problem restricting the development of gene therapy. In recent years, ultrasound-targeted microbubble destruction (UTMD) has become a safe and effective transfection method that is widely used in the basic research of gene therapy for heart and tumor diseases. Here, we synthesized cationic microbubbles to encapsulate miR-145 and targeted their release into VSMCs in vitro and in vivo using ultrasound. The feasibility of this gene therapy was verified by fluorescence microscopy and an in vivo imaging system. The results showed that treatment with miR-145 delivered via UTMD considerably improved the gene transfection efficiency and promoted the contraction phenotype of VSMCs in vitro. In vivo, this treatment reduced the atherosclerotic plaque area by 48.04% compared with treatment with free miR-145. Therefore, UTMD-mediated miRNA therapy may provide a new targeted therapeutic approach for atherosclerotic plaques.

Altered Tregs Differentiation and Impaired Autophagy Correlate to Atherosclerotic Disease

Atherosclerosis is a progressive vascular disease representing the primary cause of morbidity and mortality in developed countries. Formerly, atherosclerosis was considered as a mere passive accumulation of lipids in blood vessels. However, it is now clear that atherosclerosis is a complex and multifactorial disease, in which the involvement of immune cells and inflammation play a key role. A variety of studies have shown that autophagy-a cellular catalytic mechanism able to remove injured cytoplasmic components in response to cellular stress-may be proatherogenic. So far, in this context, its role has been investigated in smooth muscle cells, macrophages, and endothelial cells, while the function of this catabolic protective process in lymphocyte functionality has been overlooked. The few studies carried out so far, however, suggested that autophagy modulation in lymphocyte subsets may be functionally related to plaque formation and development. Therefore, in this research, we aimed at better clarifying the role of lymphocyte subsets, mainly regulatory T cells (Tregs), in human atherosclerotic plaques and in animal models of atherosclerosis investigating the contribution of autophagy on immune cell homeostasis. Here, we investigate basal autophagy in a mouse model of atherosclerosis, apolipoprotein E (ApoE)-knockout (KO) mice, and we analyze the role of autophagy in driving Tregs polarization. We observed defective maturation of Tregs from ApoE-KO mice in response to tumor growth factor-β (TGFβ). TGFβ is a well-known autophagy inducer, and Tregs maturation defects in ApoE-KO mice seem to be related to autophagy impairment. In this work, we propose that autophagy underlies Tregs maturation, advocating that the study of this process in atherosclerosis may open new therapeutic strategies.

Vascular and inflammatory mineralocorticoid receptors in kidney disease

Mineralocorticoid receptor (MR) activation in the kidney can occur outside the aldosterone-sensitive distal nephron in sites including the endothelium, smooth muscle and inflammatory cells. MR activation in these cells has deleterious effects on kidney structure and function by promoting oxidative injury, endothelial dysfunction and stiffness, vascular remodelling and calcification, decreased relaxation and activation of T cells and pro-inflammatory macrophages. Here, we review the data showing the cellular consequences of MR activation in endothelial, smooth muscle and inflammatory cells and how this affects the kidney in pathological situations. The evidence demonstrating a benefit of pharmacological or genetic MR inhibition in various models of kidney disease is also discussed.

Vascular mineralocorticoid receptor activation and disease

Mineralocorticoid receptor activation in endothelial and smooth muscle cells can promote vascular disease by increasing oxidative stress, promoting inflammation, accelerating vascular stiffness, remodeling, and calcification, altering vessel responsiveness to various vasoactive factors, thus altering vascular tone and blood pressure, and by altering angiogenesis. Here, we review the recent evidence highlighting the impact of vascular mineralocorticoid receptor activation in pathological situations, including kidney injury, vascular injury associated with metabolic diseases, atherosclerosis, cerebral vascular injury during hypertension, vascular stiffening and aging, pulmonary hypertension, vascular calcification, cardiac remodeling, wound healing, inflammation, thrombosis, and disorders related to angiogenic defects in the eye. The possible mechanisms implicating mineralocorticoid receptor activation in various vascular disorders are discussed. Altogether, recent evidence points towards pharmacological mineralocorticoid receptor inhibition as a strategy to treat diseases in which overactivation of the mineralocorticoid receptor in endothelial and/or smooth muscle cells may play a pivotal role.

Modelling of atherosclerosis in genetically modified animals

Atherosclerosis is a lipid-driven, chronic inflammatory disease that leads to plaque formation at specific sites of the arterial tree. Being the common cause of many cardiovascular disorders, atherosclerosis makes a tremendous impact on morbidity and mortality rates of cardiovascular diseases (CVDs) in countries with higher income. Animal models of atherosclerosis are utilized as useful tools for studying the aetiology, pathogenesis and complications of atherosclerosis, thus, providing a valuable platform for the efficacy testing of different pharmacological therapies and validation of imaging techniques. To date, a large variety of models is available. Pathophysiological changes can be induced in animals by either an atherogenic diet or genetic manipulations. The discussion of advantages and disadvantages of some murine, rabbit and porcine genetic models currently available for the atherosclerosis research is the scope of the following review.