CD40-targeting magnetic nanoparticles for MRI/optical dual-modality molecular imaging of vulnerable atherosclerotic plaques.

BACKGROUND AND AIMS: Acute coronary syndrome caused by vulnerable plaque rupture or erosion is a leading cause of death worldwide. CD40 has been reported to be highly expressed in atherosclerotic plaques and closely related to plaque stability. Therefore, CD40 is expected to be a potential target for the molecular imaging of vulnerable plaques in atherosclerosis. We aimed to design a CD40-targeted magnetic resonance imaging (MRI)/optical multimodal molecular imaging probe and explore its ability to detect and target vulnerable atherosclerotic plaques. METHODS: CD40-Cy5.5 superparamagnetic iron oxide nanoparticles (CD40-Cy5.5-SPIONs), which comprise a CD40-targeting multimodal imaging contrast agent, were constructed by conjugating CD40 antibody and Cy5.5-N-hydroxysuccinimide ester with SPIONs. During this in vitro study, we observed the binding ability of CD40-Cy5.5-SPIONs with RAW 264.7 cells and mouse aortic vascular smooth muscle cells (MOVAS) after different treatments, using confocal fluorescence microscopy and Prussian blue staining. An in vivo study involving ApoE-/- mice fed a high-fat diet for 24-28 weeks was performed. 24 h after intravenous injection of CD40-Cy5.5-SPIONs, fluorescence imaging and MRI were performed. RESULTS: CD40-Cy5.5-SPIONs bind specifically to tumor necrosis factor (TNF)-α-treated macrophages and smooth muscle cells. Fluorescence imaging results showed that, compared with the control group and the atherosclerosis group injected with non-specific bovine serum albumin (BSA)-Cy5.5-SPIONs, the atherosclerotic group injected with CD40-Cy5.5-SPIONs had a stronger fluorescence signal. T2-weighted images showed that the carotid arteries of atherosclerotic mice injected with CD40-Cy5.5-SPIONs had a significant substantial T2 contrast enhancement effect. CONCLUSIONS: CD40-Cy5.5-SPIONs could potentially serve as an effective MRI/optical probe for vulnerable atherosclerotic plaques during non-invasive detection.

Soluble epoxide hydrolase inhibitor, TUPS, attenuates isoproterenol/angiotensin II-induced cardiac hypertrophy through mammalian target of rapamycin-mediated autophagy inhibition.

OBJECTIVES: To investigate the potential role and mechanism of TUPS, a soluble epoxide hydrolase inhibitor, in cardiac hypertrophy. METHODS: Rat and H9C2 cell models of cardiac hypertrophy were induced by isoproterenol and angiotensin II, respectively, followed by TUPS treatment. The expression of hypertrophic markers, ANP and BNP, was determined by quantitative real-time PCR. The abundance of Beclin-1, LC3, p-AMPK and phosphorylated-mammalian target of rapamycin (p-mTOR) proteins was analysed by Western blot and immunohistocytology. Cell morphology and viability were evaluated by F-actin staining and MTS. H9C2 cells were transfected with GFP-LC3 to evaluate autophagy flux. KEY FINDINGS: TUPS significantly inhibited rat heart size, heart weight-to-body weight ratio, heart wall thickness, hypertrophic H9C2 cell swelling and viability suppression as well as the expression of ANP and BNP genes in hypertrophic models. In addition, autophagic markers Beclin-1 and LC3 were elevated in both cellular and animal models, which were suppressed by TUPS, with corresponding changes of autophagy flux. The abundance of p-AMPK was increased, while p-mTOR was decreased in hypertrophic cells, which were abolished by TUPS. Rapamycin decreased p-mTOR level, increased Beclin-1 and LC3 expression and induced cell size enlargement and cell viability inhibition in hypertrophic H9C2 cells treated with TUPS. CONCLUSIONS: TUPS inhibits cardiac hypertrophy by regulating mTOR/autophagy axis.