Vasostatin-2 inhibits cell proliferation and adhesion in vascular smooth muscle cells, which are associated with the progression of atherosclerosis

Vasostatins: new molecular targets for atherosclerosis, post-ischaemic angiogenesis, and arteriogenesis

The chromogranin-secretogranin secretory proteins-granins-are acidic proteins localized in granules of endocrine cells and neurons. The chromogranin family includes chromogranins A (CgA) and B, as well as secretogranin II (once called chromogranin C). Members of this family undergo catalytic proteolysis to produce active peptides. The CgA-derived peptides vasostatin-1 and vasostatin-2, in particular, appear to protect against atherosclerosis, suppressing the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1, as well as exerting vasodilatory effects by enhancing nitric oxide bioavailability. Vasostatin-1 also suppresses vasoconstriction and abnormal angiogenesis. Vasostatin-1 and vasostatin-2 may be novel therapeutic targets for atherosclerosis and coronary heart disease, also protecting the myocardium against ischaemic damage.

[Gly14]-Humanin inhibits an angiotensin II-induced vascular smooth muscle cell phenotypic switch via ameliorating intracellular oxidative stress

Angiotensin II (AngII) is involved in the pathogenesis of hypertensive artery remodeling by inducing a phenotypic switch in vascular smooth muscle cells [Gly14]-Humanin (HNG), a humanin analogue, exerts potent cytoprotective effects both in vitro and in vivo. This study aimed to investigate the effects of HNG on an AngII-induced phenotypic switch in VSMCs and the potential mechanisms underlying these effects. The roles of [Gly14]-Humanin in AngII-stimulated VSMCs proliferation and migration was detected by CCK-8 assay, Cell cycle analysis, wound healing assay, trsnswell assay and western blot. The mechanism by which [Gly14]-Humanin regulates VSMC phenotypic switch was determined by intracellular oxidative stress detection, transcriptomic analysis and qRT-PCR. The results showed that HNG inhibited AngII-induced VSMC proliferation and migration and maintained a stable VSMC contractile phenotype. In addition, HNG reduced the level of AngII-induced oxidative stress in vascular smooth muscle cells. This process could be accomplished by inhibiting nicotinamide adenine dinucleotide phosphate oxidase activity. In conclusion, the results suggested that HNG ameliorated intracellular oxidative stress by inhibiting NAD(P)H oxidase activity, thereby suppressing the AngII-induced VSMC phenotype switch. Thus, HNG is a potential drug to ameliorate artery remodeling in hypertension.

Protective effect of vasostatin-1 plasmid-like nanoparticles on aortic aneurysm and its mechanism

Vasostatin 1 (VS-1) plays an important role in the regulation of various tissue injury and repair processes, but its role in aortic aneurysm remains unclear. The plasmid-like nanoparticles containing the vasostatin-1 gene Pul-PGEA-pCas-sgVs-1 were constructed, and their guarantee, safety, hemolysis, and particle size were analyzed. Eighty-four eight-week-old male ApoE-mice were randomly divided into blank group (without any treatment), model group (Ang II aortic aneurysm model + tail injection of PBS), control group (modeling + tail injection of Pul-PGEA-pCas9), and experimental group (modeling + tail injection of Pul-PGEA-pCas-sgVs-1), with 21 rats in each group. The incidence, mortality, and maximum diameter of abdominal aortic aneurysm (AAA) and the contents of high sensitivity C-reactive protein (HS-CRP), soluble intercellular adhesion molecule-1 (ICAM-1), soluble vascular cell adhesion molecule-1 (VCAM-1), and TNF-a in serum were compared in different groups of mice. The results showed that Pul-PGEA-pCas-sgVs-1 had good biosafety and transfection ability. The maximum diameter of abdominal aorta, incidence of abdominal aortic aneurysm, mortality, and the expression levels of HS-CRP, ICAM-1, VCAM-1, and TNF-a in the experimental group were lower than those in the model group (P< 0.05). These results indicated that the plasmid-like nanoparticles Pul-PGEA-pCas-sgVs-1 can inhibit the development of aorta by down-regulating the expression of inflammatory factors, which played a good protective role on the aorta.

Deletion of Fam172a accelerates advanced atherosclerosis and induces plaque instability

BACKGROUND AND AIMS

Vascular smooth muscle cells (VSMCs) play a critical role in atherosclerosis. The family with sequence similarity 172, member A (FAM172A) is a novel protein and its role in atherosclerosis has not been explored so far. Therefore, our aim is to investigate whether FAM172A affects atheroprogression through VSMCs and its possible mechanism.

METHODS

Fam172a^-/- mice were generated using CRISPR/Cas9 technology. Fam172a^-/- and Apoe^-/- double knockout (Fam172a^-/-/Apoe^-/-) mice and their littermates (Fam172a^+/+/Apoe^-/-) were fed with a Western diet for 18 weeks to induce advanced atherosclerotic lesions. The role and mechanism of Fam172a in phenotypic switching, proliferation and migration of VSMCs were investigated through in vivo and in vitro experiments.

RESULTS

Compared with Fam172a^+/+/Apoe^-/- mice, Fam172a^-/-/Apoe^-/- mice showed increased atherosclerotic lesion size and plaque instability such as increased necrotic core area and decreased fiber deposition. Additionally, knockout of Fam172a promoted expression of CD68 and KLF4 and decreased expression of α-SMA and SM22α in atherosclerotic lesions. Furthermore, overexpression of Fam172a promoted Movas cells proliferation and migration, increased expression of α-SMA and SM22α and decreased expression of KLF4. Meanwhile, knockdown of Fam172a in Movas cells and deletion of Fam172a in VSMCs from Fam172a^-/-/Apoe^-/- mice showed opposite phenotypes. Similar phenotypes were also observed in human aortic smooth muscle cells.

CONCLUSIONS

Our results provide the first direct evidence that Fam172a has a protective role in advanced atherosclerosis by increasing atherosclerotic plaque stability and inhibiting transition of VSMCs from contractile to synthetic phenotype, which may be through KLF4-dependent pathway.

The Emerging Roles of Chromogranins and Derived Polypeptides in Atherosclerosis, Diabetes, and Coronary Heart Disease

Chromogranin A (CgA), B (CgB), and C (CgC), the family members of the granin glycoproteins, are associated with diabetes. These proteins are abundantly expressed in neurons, endocrine, and neuroendocrine cells. They are also present in other areas of the body. Patients with diabetic retinopathy have higher levels of CgA, CgB, and CgC in the vitreous humor. In addition, type 1 diabetic patients have high CgA and low CgB levels in the circulating blood. Plasma CgA levels are increased in patients with hypertension, coronary heart disease, and heart failure. CgA is the precursor to several functional peptides, including catestatin, vasostatin-1, vasostatin-2, pancreastatin, chromofungin, and many others. Catestatin, vasostain-1, and vasostatin-2 suppress the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in human vascular endothelial cells. Catestatin and vasostatin-1 suppress oxidized low-density lipoprotein-induced foam cell formation in human macrophages. Catestatin and vasostatin-2, but not vasostatin-1, suppress the proliferation and these three peptides suppress the migration in human vascular smooth muscles. Chronic infusion of catestatin, vasostatin-1, or vasostatin-2 suppresses the development of atherosclerosis of the aorta in apolipoprotein E-deficient mice. Catestatin, vasostatin-1, vasostatin-2, and chromofungin protect ischemia/reperfusion-induced myocardial dysfunction in rats. Since pancreastatin inhibits insulin secretion from pancreatic β-cells, and regulates glucose metabolism in liver and adipose tissues, pancreastatin inhibitor peptide-8 (PSTi8) improves insulin resistance and glucose homeostasis. Catestatin stimulates therapeutic angiogenesis in the mouse hind limb ischemia model. Gene therapy with secretoneurin, a CgC-derived peptide, stimulates postischemic neovascularization in apolipoprotein E-deficient mice and streptozotocin-induced diabetic mice, and improves diabetic neuropathy in db/db mice. Therefore, CgA is a biomarker for atherosclerosis, diabetes, hypertension, and coronary heart disease. CgA- and CgC--derived polypeptides provide the therapeutic target for atherosclerosis and ischemia-induced tissue damages. PSTi8 is useful in the treatment of diabetes.

miR-140-5p regulates vascular smooth muscle cell viability, migration and apoptosis by targeting ROBO4 gene expression in atherosclerosis

MicroRNAs (miRs) are essential regulators of atherosclerosis (AS) development; however, the pathogenic roles of miR-140-5p during AS development are not completely understood. The present study investigated the effects of miR‑140-5p on human vascular smooth muscle cells (VSMCs) and its target gene. miR-140-5p and roundabout guidance receptor 4 (ROBO4) mRNA expression levels were determined by performing reverse transcription-quantitative PCR. ROBO4 protein expression levels were analyzed via western blotting. Cell viability, migration, invasion and apoptosis were evaluated by conducting Cell Counting Kit-8, Transwell and flow cytometry assays, respectively. The binding of miR-140-5p to ROBO4 mRNA was verified using the dual-luciferase reporter assay. miR-140-5p was highly expressed in the plaque-containing artery tissues of patients with AS compared with healthy control tissues. Oxidized-low density lipoprotein (ox-LDL) treatment increased miR-140-5p expression and decreased ROBO4 expression in human VSMCs, which promoted VSMC viability, migration and invasion, but suppressed apoptosis compared with the control group. The effects of ox-LDL treatment on VSMCs were attenuated by miR-140-5p inhibitor. miR-140-5p directly bound to the 3'-untranslated region of ROBO4 mRNA. ROBO4 overexpression mitigated the effects of ox-LDL treatment on VSMC viability, migration, invasion and apoptosis. Therefore, the present study suggested that high level miR-140-5p expression promoted VSMC viability, migration, and invasion, and suppressed VSMC apoptosis by reducing ROBO4 gene expression. The present study provided novel insights into AS pathogenesis that may aid the development of new strategies for the treatment and prevention of AS.

Paired box 9 regulates VSMC phenotypic transformation, proliferation, and migration via sonic hedgehog

AIMS

Vascular smooth muscle cells (VSMCs) play a crucial role in the progression of atherosclerosis. Paired box 9 (Pax9) is a member of the Pax gene family which participates in the development of various tissues and organs. However, the effect of Pax9 on atherosclerosis and VSMCs and the underlying mechanisms remain unclear.

MAIN METHODS

Western blotting was performed to assess Pax9 expression in atherosclerosis and VSMCs. Pax9 siRNA and overexpression plasmid were constructed to explore the biological function. Cell proliferation assay, phalloidin staining, and Transwell assay, accompanied by the sonic hedgehog (Shh) signaling pathway antagonist, cyclopamine (5 μM) and agonist, SAG (100 nM), were used to evaluate the VSMC phenotype, proliferation, and migration, as well as explore the associated mechanisms.

KEY FINDINGS

We first discovered Pax9 to be significantly increased in atherosclerotic mice and platelet-derived growth factor-BB (PDGF-BB)-induced VSMCs. Pax9 knockdown inhibited the phenotypic transformation, proliferation, and migration of VSMCs, whereas the opposite effect was observed when Pax9 was overexpressed. Next, we established that Shh was activated in PDGF-BB-induced VSMCs. Moreover, Pax9 overexpression further activated Shh and exacerbated the phenotypic transformation, proliferation, and migration of PDGF-BB-induced VSMCs. These changes were effectively inhibited by treatment with the Shh signaling pathway antagonist. Consistently, Pax9 knockdown down-regulated Shh expression and inhibited the phenotypic transformation, proliferation, and migration of PDGF-BB-induced VSMCs. Treatment with the Shh signaling pathway agonist prevented these changes.

SIGNIFICANCE

Pax9 regulated VSMC phenotypic transformation, proliferation, and migration via Shh, which may represent a novel target for the treatment of atherosclerosis.

TRIM7 promotes proliferation and migration of vascular smooth muscle cells in atherosclerosis through activating c-Jun/AP-1

Atherosclerosis (AS), with associated risk of stroke or cerebrovascular disease, is one of the most common causes of death globally. It has been well established that tripartite motif-containing protein 7 Tripartite Motif-containing 7 (Trim7), as an E3 ubiquitin protein ligase, is involved in protein ubiquitination and thus regulating cellular proliferation. Moreover, TRIM7 is upregulated in advanced carotid AS. However, the detailed mechanism of TRIM7 on regulation of AS remains unclear. In the present study, we firstly discovered that TRIM7 expression was robustly induced in platelet-derived growth factor type BB-treated vascular smooth muscle cells (VSMCs) and human atherosclerotic plaques. Functional approaches established that knockdown of TRIM7 inhibited proliferation and migration of VSMCs, as well as arrested the cell cycle at G1-S, thus suppressing AS progression. Our results also identified that c-Jun/activator protein 1 (AP-1) signaling pathway was activated by TRIM7. Moreover, gain- and loss-of-function studies revealed that TRIM7 could promote proliferation and migration of VSMCs via activation of c-Jun/AP-1 signaling pathway. Finally, by using atherogenic apolipoprotein E-deficient (apoE-/-) C57BL/6 mice with high-fat diet AS model, we demonstrated that interference of TRIM7 could effectively mitigate in vivo AS via inactivation of c-Jun/AP-1 signaling pathway. In general, activation of c-Jun/AP-1 signaling pathway via TRIM7 could be an important mechanism in AS progression, thus shedding light on the development of novel therapeutics to the treatment of the disease.

Inhibitory effects of vasostatin-1 against atherogenesis

Vasostatin-1, a chromogranin A (CgA)-derived peptide (76 amino acids), is known to suppress vasoconstriction and angiogenesis. A recent study has shown that vasostatin-1 suppresses the adhesion of human U937 monocytes to human endothelial cells (HECs) via adhesion molecule down-regulation. The present study evaluated the expression of vasostatin-1 in human atherosclerotic lesions and its effects on inflammatory responses in HECs and human THP-1 monocyte-derived macrophages, macrophage foam cell formation, migration and proliferation of human aortic smooth muscle cells (HASMCs) and extracellular matrix (ECM) production by HASMCs, and atherogenesis in apolipoprotein E-deficient (ApoE^-/-) mice. Vasostatin-1 was expressed around Monckeberg's medial calcific sclerosis in human radial arteries. Vasostatin-1 suppressed lipopolysaccharide (LPS)-induced up-regulation of monocyte chemotactic protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in HECs. Vasostatin-1 suppressed inflammatory M1 phenotype and LPS-induced interleukin-6 (IL-6) secretion via nuclear factor-κB (NF-κB) down-regulation in macrophages. Vasostatin-1 suppressed oxidized low-density lipoprotein (oxLDL)-induced foam cell formation associated with acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) and CD36 down-regulation and ATP-binding cassette transporter A1 (ABCA1) up-regulation in macrophages. In HASMCs, vasostatin-1 suppressed angiotensin II (AngII)-induced migration and collagen-3 and fibronectin expression via decreasing ERK1/2 and p38 phosphorylation, but increased elastin expression and matrix metalloproteinase (MMP)-2 and MMP-9 activities via increasing Akt and JNK phosphorylation. Vasostatin-1 did not affect the proliferation and apoptosis in HASMCs. Four-week infusion of vasostatin-1 suppressed the development of aortic atherosclerotic lesions with reductions in intra-plaque inflammation, macrophage infiltration, and SMC content, and plasma glucose level in ApoE^-/- mice. These results indicate the inhibitory effects of vasostatin-1 against atherogenesis. The present study provided the first evidence that vasostatin-1 may serve as a novel therapeutic target for atherosclerosis.

Roles of Cells from the Arterial Vessel Wall in Atherosclerosis

Atherosclerosis has been identified as a chronic inflammatory disease of the arterial vessel wall. Accumulating evidence indicates that different cells from the tunica intima, media, adventitia, and perivascular adipose tissue not only comprise the intact and normal arterial vessel wall but also participate all in the inflammatory response of atherosclerosis via multiple intricate pathways. For instance, endothelial dysfunction has historically been considered to be the initiator of the development of atherosclerosis. The migration and proliferation of smooth muscle cells also play a pivotal role in the progression of atherosclerosis. Additionally, the fibroblasts from the adventitia and adipocytes from perivascular adipose tissue have received considerable attention given their special functions that contribute to atherosclerosis. In addition, numerous types of cytokines produced by different cells from the arterial vessel wall, including endothelium-derived relaxing factors, endothelium-derived contracting factors, tumor necrosis factors, interleukin, adhesion molecules, interferon, and adventitium-derived relaxing factors, have been implicated in atherosclerosis. Herein, we summarize the possible roles of different cells from the entire arterial vessel wall in the pathogenesis of atherosclerosis.

Plasma levels of vasostatin-1, a chromogranin A fragment, are associated with carotid artery maximum stenosis: A pilot study

BACKGROUND

Chromogranin A (CgA), a circulating protein released by the neuroendocrine system, can regulate vascular physiology and angiogenesis. Full-length CgA (CgA_1-439) and its fragment CgA_1-76 (called vasostatin-1, VS-1) preserve the physiological integrity of the endothelial barrier function and are antiangiogenic, whereas CgA_1-373 is proangiogenic. We investigated whether these polypeptides are altered in patients with various degrees of carotid artery atherosclerosis.

METHODS

We studied 81 patients with carotid artery atherosclerosis, asymptomatic for cerebrovascular diseases. Carotid arteries were examined by Doppler ultrasound and plaque characteristics were recorded. Plasma levels of CgA_1-439, VS-1, CgA_1-373, and total-CgA (CgA_1-439 plus truncated fragments lacking part or the entire C-terminal region) were assessed by specific ELISAs.

RESULTS

Plasma levels of VS-1 and total-CgA correlated with carotid artery maximum stenosis (r=0.349, p=0.001 and r=0.256, p=0.021, respectively). Stepwise multiple regression analysis indicated that VS-1 was a significant predictor of maximum stenosis after adjustment for age, gender, and conventional risk factors for atherosclerosis (regression coefficient=12.42, SE=4.84, p=0.012). In addition, logistic regression analysis indicated that relatively high levels of full-length CgA, but not total-CgA, predict the presence of hypoechoic, lipid-rich plaques (OR=1.47; 95% CI: 1.19-1.81, p=0.0003).

CONCLUSION

VS-1 is independently associated with carotid artery maximum stenosis. Furthermore, full-length CgA is an independent indicator of hypoechoic plaques, likely reflecting initial stages of atherosclerosis. Given the known capability of CgA and VS-1 to regulate vascular function and angiogenesis these polypeptides might play a role in the regulation of atherosclerosis pathophysiology.