Intermedin1-53 Attenuates Abdominal Aortic Aneurysm by Inhibiting Oxidative Stress.

Oxidative stress plays a critical role in the development of abdominal aortic aneurysm (AAA). Intermedin (IMD) is a regulator of oxidative stress. Here, we investigated whether IMD reduces AAA by inhibiting oxidative stress. In angiotensin II-induced ApoE-/- mouse and CaCl2-induced C57BL/6J mouse model of AAA, IMD1-53 significantly reduced the incidence of AAA and maximal aortic diameter. Ultrasonography, hematoxylin, and eosin staining and Verhoeff-van Gieson staining showed that IMD1-53 significantly decreased the enlarged aortas and elastic lamina degradation induced by angiotensin II or CaCl2. Mechanistically, IMD1-53 attenuated oxidative stress, inflammation, vascular smooth muscle cell apoptosis, and matrix metalloproteinase activation. IMD1-53 inhibited the activation of redox-sensitive signaling pathways, decreased the mRNA and protein expression of nicotinamide adenine dinucleotide phosphate oxidase subunits, and reduced the activity of nicotinamide adenine dinucleotide phosphate oxidase in AAA mice. Expression of Nox4 was upregulated in human AAA segments and in angiotensin II-treated mouse aortas and was markedly decreased by IMD1-53. In vitro, vascular smooth muscle cells with small-interfering RNA knockdown of IMD showed significantly increased angiotensin II-induced reactive oxygen species, and small-interfering RNA knockdown of Nox4 markedly inhibited the reactive oxygen species. IMD knockdown further increased the apoptosis of vascular smooth muscle cells and inflammation, which was reversed by Nox4 knockdown. Preincubation with IMD17-47 and protein kinase A inhibitor H89 inhibited the effect of IMD1-53, reducing Nox4 protein levels. IMD1-53 could have a protective effect on AAA by inhibiting oxidative stress.

Lu WW ，Jia LX ，Ni XQ ，Zhao L ，Chang JR ，Zhang JS ，Hou YL ，Zhu Y ，Guan YF ，Yu YR ，Du J ，Tang CS ，Qi YF ... -  《-》

Inhibition of endoplasmic reticulum stress by intermedin1-53 attenuates angiotensin II-induced abdominal aortic aneurysm in ApoE KO Mice.

Ni XQ ，Lu WW ，Zhang JS ，Zhu Q ，Ren JL ，Yu YR ，Liu XY ，Wang XJ ，Han M ，Jing Q ，Du J ，Tang CS ，Qi YF ... -  《-》

Genetic Ablation of MicroRNA-33 Attenuates Inflammation and Abdominal Aortic Aneurysm Formation via Several Anti-Inflammatory Pathways.

Abdominal aortic aneurysm (AAA) is an increasingly prevalent and ultimately fatal disease with no effective pharmacological treatment. Because matrix degradation induced by vascular inflammation is the major pathophysiology of AAA, attenuation of this inflammation may improve its outcome. Previous studies suggested that miR-33 (microRNA-33) inhibition and genetic ablation of miR-33 increased serum high-density lipoprotein cholesterol and attenuated atherosclerosis. MiR-33a-5p expression in central zone of human AAA was higher than marginal zone. MiR-33 deletion attenuated AAA formation in both mouse models of angiotensin II- and calcium chloride-induced AAA. Reduced macrophage accumulation and monocyte chemotactic protein-1 expression were observed in calcium chloride-induced AAA walls in miR-33-/- mice. In vitro experiments revealed that peritoneal macrophages from miR-33-/- mice showed reduced matrix metalloproteinase 9 expression levels via c-Jun N-terminal kinase inactivation. Primary aortic vascular smooth muscle cells from miR-33-/- mice showed reduced monocyte chemotactic protein-1 expression by p38 mitogen-activated protein kinase attenuation. Both of the inactivation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase were possibly because of the increase of ATP-binding cassette transporter A1 that is a well-known target of miR-33. Moreover, high-density lipoprotein cholesterol derived from miR-33-/- mice reduced expression of matrix metalloproteinase 9 in macrophages and monocyte chemotactic protein-1 in vascular smooth muscle cells. Bone marrow transplantation experiments indicated that miR-33-deficient bone marrow cells ameliorated AAA formation in wild-type recipients. MiR-33 deficiency in recipient mice was also shown to contribute the inhibition of AAA formation. These data strongly suggest that inhibition of miR-33 will be effective as a novel strategy for treating AAA.

Nakao T ，Horie T ，Baba O ，Nishiga M ，Nishino T ，Izuhara M ，Kuwabara Y ，Nishi H ，Usami S ，Nakazeki F ，Ide Y ，Koyama S ，Kimura M ，Sowa N ，Ohno S ，Aoki H ，Hasegawa K ，Sakamoto K ，Minatoya K ，Kimura T ，Ono K ... -  《-》

Targeting vascular smooth muscle cell dysfunction with xanthine derivative KMUP-3 inhibits abdominal aortic aneurysm in mice.

Inflammation, oxidative stress, matrix degradation, medial calcification and vascular smooth muscle cell (VSMC) loss are prominent features in abdominal aortic aneurysm (AAA). VSMC phenotypic switch to a proinflammatory state and VSMC apoptosis could be targetable mechanisms implicated in the pathogenesis of AAA formation. Herein, we investigated the hypothesis that a xanthine derivative (KMUP-3) might suppress AAA through inhibition of VSMC phenotypic switch and apoptosis. In vitro, VSMC calcification was induced using β-glycerophosphate. In vivo, AAA was induced using angiotensin II (1000 ng/kg per minute) infusion for 4 weeks in apolipoprotein E-deficient mice. As determined by alizarin red S staining and calcium content measurements, KMUP-3 suppressed VSMC calcification. During VSMC calcification, KMUP-3 inhibited mTOR and β-catenin upregulation, essential for VSMC phenotypic switch, while it enhanced AMP-activated protein kinase (AMPK) activation that protects against VSMC phenotypic switch. Moreover, KMUP-3 attenuated VSMC apoptosis with an increased Bcl-2/Bax ratio and reduced activated caspase-3 expression. During AAA formation, treatment with KMUP-3 inhibited phosphorylated mTOR expression and increased phosphorylated AMPK expression in the medial layer. In addition, KMUP-3 treatment suppressed aortic dilatation together with reduction in proinflammatory cytokines and infiltrating macrophages, attenuation of medial VSMC apoptosis and mitigation of reactive oxygen species generation, matrix-degrading proteinase activities, elastin breakdown and vascular calcification. Treatment with KMUP-3 inhibits aneurysm growth possibly through its interference with signaling pathways involved in VSMC phenotypic switch and apoptosis. These findings provide a proof-of-concept validation for VSMC dysfunction as a potential therapeutic target in AAA.

Lai CH ，Chang CW ，Lee FT ，Kuo CH ，Hsu JH ，Liu CP ，Wu HL ，Yeh JL ... -  《-》

Intermedin1-53 attenuates vascular calcification in rats with chronic kidney disease by upregulation of α-Klotho.

Deficiency in α-Klotho is involved in the pathogenesis of vascular calcification. Since intermedin (IMD)1-53 (a calcitonin/calcitonin gene-related peptide) protects against vascular calcification, we studied whether IMD1-53 inhibits vascular calcification by upregulating α-Klotho. A rat model of chronic kidney disease (CKD) with vascular calcification induced by the 5/6 nephrectomy plus vitamin D3 was used for study. The aortas of rats with CKD showed reduced IMD content but an increase of its receptor, calcitonin receptor-like receptor, and its receptor modifier, receptor activity-modifying protein 3. IMD1-53 treatment reduced vascular calcification. The expression of α-Klotho was greatly decreased in the aortas of rats with CKD but increased in the aortas of IMD1-53-treated rats with CKD. In vitro, IMD1-53 increased α-Klotho protein level in calcified vascular smooth muscle cells. α-Klotho knockdown blocked the inhibitory effect of IMD1-53 on vascular smooth muscle cell calcification and their transformation into osteoblast-like cells. The effect of IMD1-53 to upregulate α-Klotho and inhibit vascular smooth muscle cell calcification was abolished by knockdown of its receptor or its modifier protein, or treatment with the protein kinase A inhibitor H89. Thus, IMD1-53 may attenuate vascular calcification by upregulating α-Klotho via the calcitonin receptor/modifying protein complex and protein kinase A signaling.

Chang JR ，Guo J ，Wang Y ，Hou YL ，Lu WW ，Zhang JS ，Yu YR ，Xu MJ ，Liu XY ，Wang XJ ，Guan YF ，Zhu Y ，Du J ，Tang CS ，Qi YF ... -  《-》