METTL3-mediated m6A modification of NORAD inhibits the ferroptosis of vascular smooth muscle cells to attenuate the aortic dissection progression in an YTHDF2-dependent manner.

Ferroptosis of vascular smooth muscle cells (VSMCs) is related to the incidence of aortic dissection (AD). Long non-coding RNA (lncRNA) NORAD plays a crucial role in the progression of various diseases. The present study aimed to investigate the effects of NORAD on the ferroptosis of VSMCs and the molecular mechanisms. The expression of NORAD, HUR, and GPX4 was detected using quantitative real-time PCR (qPCR) or western blot. Ferroptosis was evaluated by detecting lactate dehydrogenase (LDH) activity, lipid reactive oxygen species (ROS), malonaldehyde (MDA) content, L-Glutathione (GSH) level, Fe2+ content, and ferroptosis-related protein levels. The molecular mechanism was assessed using RNA pull-down, RNA-binding protein immunoprecipitation (RIP), and luciferase reporter assay. The histology of aortic tissues was assessed using H&E, elastic Verhoeff-Van Gieson (EVG), and Masson staining assays. The data indicated that NORAD was downregulated in patients with AD and AngII-treated VSMCs. Overexpression of NORAD promoted VSMC growth and inhibited the ferroptosis induced by AngII. Mechanistically, NORAD interacted with HUR, which promoted GPX4 mRNA stability and elevated GPX4 levels. Knockdown of GPX4 abrogated the effects of NORAD on cell growth and ferroptosis of AngII-treated VSMCs. Moreover, METTL3 promoted m6A methylation of NORAD in an YTHDF2-dependent manner. In addition, NORAD attenuated AAD symptoms, incidence, histopathology, inflammation, and ferroptosis in AAD mice. In conclusion, METTL3-mediated NORAD inhibited ferroptosis of VSMCs via the HUR/GPX4 axis and decelerated AAD progression, suggesting that NORAD may be an AD therapeutic target.

Epitranscriptome analysis of NAD-capped RNA by spike-in-based normalization and prediction of chronological age.

Nicotinamide adenine dinucleotide (NAD) can be used as an initiating nucleotide in RNA transcription to produce NAD-capped RNA (NAD-RNA). RNA modification by NAD that links metabolite with expressed transcript is a poorly studied epitranscriptomic modification. Current NAD-RNA profiling methods involve multi-steps of chemo-enzymatic labeling and affinity-based enrichment, thus presenting a critical analytical challenge to remove unwanted variations, particularly batch effects. Here, we propose a computational framework, enONE, to remove unwanted variations. We demonstrate that designed spike-in RNA, together with modular normalization procedures and evaluation metrics, can mitigate technical noise, empowering quantitative and comparative assessment of NAD-RNA across different datasets. Using enONE and a human aging cohort, we reveal age-associated features of NAD-capping and further develop an accurate RNA-based aging clock that combines signatures from both transcriptome and NAD-modified epitranscriptome. enONE facilitates the discovery of NAD-RNA responsive to physiological changes, laying an important foundation for functional investigations into this modification.

Comparative effectiveness and safety of laser, needle, and "quick fenestrater" in in situ fenestration during thoracic endovascular aortic repair.

Background: Special instruments are needed for the revascularization of aortic branches in in situ fenestration during thoracic endovascular aortic repair (TEVAR). This prospective study compared the effectiveness and safety of three currently used fenestraters: laser, needle, and Quick Fenestrater (QF). Methods: In all, 101 patients who underwent TEVAR for aortic disease (dissection, n = 62; aneurysm, n = 16, or ulcer, n = 23) were enrolled. All patients were randomly assigned to three groups: 34 were assigned to laser fenestration, 36 to needle fenestration, and 31 to QF fenestration. The epidemiological data, treatment, imaging findings, and follow-up outcomes were analyzed using data from the medical records. Results: The technical success rates of the laser, needle, and QF fenestration groups were 94.1%, 94.4%, and 100% (p > 0.05). After correction of mixed factors such as age and gender, it was showed the average operative time (Laser group: 130.01 ± 9.36 min/ Needle group: 149.80 ± 10.18 min vs. QF group: 101.10 ± 6.75 min, p < 0.001), fluoroscopy time (Laser group: 30.16 ± 9.81 min/ Needle group: 40.20 ± 9.91 min vs. QF group: 19.91 ± 5.42 min, p < 0.001), fenestration time (Laser group 5.50 ± 3.10 min / Needle group 3.50 ± 1.50 min vs. QF group 0.67 ± 0.06 min, p < 0.001), and guide wire passage time after fenestration (Laser group 5.10 ± 1.70 min / Needle group 4.28 ± 1.60 min vs. QF group 0.07 ± 0.01 min, p < 0.001) were all shorter with QF fenestration than with the other two tools. The overall perioperative complication rates of the laser, needle, and QF fenestration groups were 5.9%, 5.6%, and 0% (p > 0.05): One case of sheath thermal injury and one case of vertebral artery ischemia occurred in the laser fenestration group; one case each of access site hematoma and brachial artery thrombosis were reported in the needle fenestration group. 89 (88.1%, 89/101) patients were followed for a median of 12.6 ± 1.6 months. The overall postoperative complication rates of the laser, needle, and QF fenestration groups were 3.3%, 6.5%, and 0% (p > 0.05): In the laser fenestration group, there was one death due to postoperative ST-segment elevation myocardial infarction; in the needle fenestration group, one patient developed occlusion of the bridge stent; no complications occurred in the QF group. Conclusion: All three fenestration methods were effective in reconstructing supra-arch artery during TEVAR. QF fenestration required less contrast agent, with a shorter surgery duration and fewer complications than laser and needle fenestration.

Dengzhan Shengmai capsule versus Aspirin in the treatment of carotid atherosclerotic plaque: A single-centre, non-inferiority, prospective, randomised controlled trial.

BACKGROUND: Aspirin is an effective antiplatelet agent for the treatment of carotid atherosclerosis. However, the high risk of bleeding events associated with the drug makes it necessary to seek a safer alternative, with similar or more efficacy than aspirin. Dengzhan Shengmai (DZSM) capsules have been widely used to treat carotid atherosclerosis, and if proven to be non-inferior to aspirin, it may be preferable over the latter for carotid atherosclerosis treatment due to its numerous advantages. We conducted a randomised trial to test the non-inferiority of DZSM to aspirin for the treatment of carotid atherosclerotic plaques. METHODS: We performed a single-centre, prospective, open-label, randomised non-inferiority trial. Patients with carotid atherosclerotic plaques were enrolled and randomly assigned (1:1) to receive either DZSM capsules or aspirin. The follow-up period was 12 months. The primary outcome was the mean change in carotid intima-media thickness (IMT). Secondary outcomes included ischaemic events, rate of lumen stenosis, lipid levels, and plaque scores, length, counts, and vulnerability. Adverse events and laboratory test results were recorded as safety outcomes. The non-inferiority of DZSM was demonstrated when the lower limit of the one-sided 97.5% confidence interval (CI) of the difference in IMT between groups was more than -0.06 mm (margin of non-inferiority). This trial has been registered at ClinicalTrials.gov (CHiCTR1900021365). RESULTS: From 1 April 2019 to 30 September 2019, 150 patients were enrolled, and there was no statistical difference in demographics between the groups. Intention-to-treat analysis showed that the decrease in IMT(∆IMT) was 0.216 ± 0.160 and 0.225 ± 0.149 mm in the DZSM and aspirin groups, respectively. The one-sided 97.5% CI for the difference between ∆IMTs was (-0.0593, +∞). The non-inferiority of DZSM was demonstrated (Pnon-inferiority = 0.0234). There was no significant difference in the incidence of ischaemic events between the groups (P = 1.0). The DZSM group had significantly reduced plaque scores (P < 0.0001), length (P < 0.0001), and counts (P < 0.0001), and improved plaque vulnerability (P < 0.0001). The DZSM group also had reduced levels of low-density lipoprotein cholesterol (LDL-C) (P < 0.0001). Finally, the DZSM group had a lower incidence of total adverse events (14.7% vs. 28%, P = 0.046), especially gastrointestinal discomfort (5.3% vs. 16%, P = 0.034). Although there was no significant difference in bleeding events (0 vs. 5.3%, P = 0.120), the DZSM group tended to have a lower incidence. CONCLUSION: This trial demonstrated that DZSM was not inferior, in efficacy, to aspirin in treating carotid atherosclerotic plaques, and was found to be superior to aspirin in terms of safety. This study provides a new approach for treating carotid plaques, especially in aspirin-intolerant patients.

Sorting Nexin 10 Mediates Metabolic Reprogramming of Macrophages in Atherosclerosis Through the Lyn-Dependent TFEB Signaling Pathway.

RATIONALE: SNX10 (sorting nexin 10) has been reported to play a critical role in regulating macrophage function and lipid metabolism. OBJECTIVE: To investigate the precise role of SNX10 in atherosclerotic diseases and the underlying mechanisms. METHODS AND RESULTS: SNX10 expression was compared between human healthy vessels and carotid atherosclerotic plaques. Myeloid cell-specific SNX10 knockdown mice were crossed onto the APOE-/- (apolipoprotein E) background and atherogenesis (high-cholesterol diet-induced) was monitored for 16 weeks. We found that SNX10 expression was increased in atherosclerotic lesions of aortic specimens from humans and APOE-/- mice. Myeloid cell-specific SNX10 deficiency (Δ knockout [KO]) attenuated atherosclerosis progression in APOE-/- mice. The population of anti-inflammatory monocytes/macrophages was increased in the peripheral blood and atherosclerotic lesions of ΔKO mice. In vitro experiments showed that SNX10 deficiency-inhibited foam cell formation through interrupting the internalization of CD36, which requires the interaction of SNX10 and Lyn-AKT (protein kinase B). The reduced Lyn-AKT activation by SNX10 deficiency promoted the nuclear translocation of TFEB (transcription factor EB), thereby enhanced lysosomal biogenesis and LAL (lysosomal acid lipase) activity, resulting in an increase of free fatty acids to fuel mitochondrial fatty acid oxidation. This further promoted the reprogramming of macrophages and shifted toward the anti-inflammatory phenotype. CONCLUSIONS: Our data demonstrate for the first time that SNX10 plays a crucial role in diet-induced atherogenesis via the previously unknown link between the Lyn-Akt-TFEB signaling pathway and macrophage reprogramming, suggest that SNX10 may be a potentially promising therapeutic target for atherosclerosis treatment.

IGFBP6 Is Downregulated in Unstable Carotid Atherosclerotic Plaques According to an Integrated Bioinformatics Analysis and Experimental Verification.

AIMS: To investigate the differentially expressed genes (DEGs) and molecular interaction in unstable atherosclerotic carotid plaques. METHODS: Gene expression datasets GSE41571, GSE118481, and E-MTAB-2055 were analyzed. Co-regulated DEGs in at least two datasets were analyzed with the enrichment of Gene Ontology Biological Process (GO-BP), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interaction (PPI) networks, interrelationships between miRNAs/transcriptional factors, and their target genes and drug-gene interactions. The expression of notable DEGs in human carotid artery plaques and plasma was further identified. RESULTS: The GO-BP enrichment analysis revealed that genes associated with inflammatory response, and extracellular matrix organization were altered. The KEGG enrichment analysis revealed that upregulated DEGs were enriched in the tuberculous, lysosomal, and chemokine signaling pathways, whereas downregulated genes were enriched in the focal adhesion and PI3K/Akt signaling pathway. Collagen type I alpha 2 chain (COL1A2), adenylate cyclase 3 (ADCY3), C-X-C motif chemokine receptor 4 (CXCR4), and TYRO protein tyrosine kinase binding protein (TYROBP) might play crucial roles in the PPI networks. In drug-gene interactions, colonystimulating factor-1 receptor had the most drug interactions. Insulin-like growth factor binding protein 6 (IGFBP6) was markedly downregulated in unstable human carotid plaques and plasma. Under a receiver operating characteristic curve analysis, plasma IGFBP6 had a significant discriminatory power (AUC, 0.894; 95% CI, 0.810-0.977), with a cutoff value of 142.08 ng/mL. CONCLUSIONS: The genes COL1A2, ADCY3, CXCR4, and TYROBP are promising targets for the prevention of unstable carotid plaque formation. IGFBP6 may be an important biomarker for predicting vulnerable plaques.

Activation of Bone Marrow-Derived Cells and Resident Aortic Cells During Aortic Injury.

BACKGROUND: The process of aortic injury, repair, and remodeling during aortic aneurysm and dissection is poorly understood. We examined the activation of bone marrow (BM)-derived and resident aortic cells in response to aortic injury in a mouse model of sporadic aortic aneurysm and dissection. MATERIALS AND METHODS: Wild-type C57BL/6 mice were transplanted with green fluorescent protein (GFP)+ BM cells. For 4 wk, these mice were either unchallenged with chow diet and saline infusion or challenged with high-fat diet and angiotensin II infusion. We then examined the aortic recruitment of GFP+ BM-derived cells, growth factor production, and the differentiation potential of GFP+ BM-derived and GFP- resident aortic cells. RESULTS: Aortic challenge induced recruitment of GFP+ BM cells and activation of GFP- resident aortic cells, both of which produced growth factors. Although BM cells and resident aortic cells equally contributed to the fibroblast populations, we did not detect the differentiation of BM cells into smooth muscle cells. Interestingly, aortic macrophages were both of BM-derived (45%) and of non-BM-derived (55%) origin. We also observed a significant increase in stem cell antigen-1 (Sca-1)+ stem/progenitor cells and neural/glial antigen 2 (NG2+) cells in the aortic wall of challenged mice. Although some of the Sca-1+ cells and NG2+ cells were BM derived, most of these cells were resident aortic cells. Sca-1+ cells produced growth factors and differentiated into fibroblasts and NG2+ cells. CONCLUSIONS: BM-derived and resident aortic cells are activated in response to aortic injury and contribute to aortic inflammation, repair, and remodeling by producing growth factors and differentiating into fibroblasts and inflammatory cells.

Reduced Facial Swelling and Incision Numbness After Q-Modified Eversion Carotid Endarterectomy in Patients with Severe Carotid Stenosis.

BACKGROUND: Carotid endarterectomy, especially eversion carotid endarterectomy (ECEA), is a standard treatment of carotid artery stenosis but continues to have deficiencies. We have described a modified ECEA technique that focuses on the quality of life (QoL), called Q-modified eversion carotid endarterectomy (QCEA). The modifications mainly include the skin incision, surgical approach, and arterial anastomosis. The purpose of the present study was to evaluate the clinical efficacy of QCEA and the QoL of patients after QCEA. METHODS: We performed a retrospective study of 109 patients were had undergone ECEA or QCEA from October 2016 to December 2017. The data from all interventions were prospectively collected in a dedicated database. The primary efficacy outcome was the composite of any stroke, myocardial infarction, or death through the 1-year follow-up period. The secondary endpoint was the QoL of patients after ECEA or QCEA on the seventh postoperative day, including incision hematoma, incision numbness, facial swelling, and scar length. RESULTS: QCEA was performed in 41 patients and ECEA in 45 patients. No statistically significant differences were found in operating or clamping time between the 2 groups. The incidence of facial swelling (4.9% vs. 28.9%; P = 0.040) and incision numbness (4.9% vs. 24.4%; P = 0.011) in the QCEA group was significantly lower than that in the ECEA group. The average scar length of the QCEA group was significantly shorter than that of the ECEA group (5.1 ± 1.4 cm vs. 7.6 ± 2.1 cm; P < 0.001). No transient ischemic attack, stroke, myocardial infarction, or mortality occurred in either group during the 1-year follow-up. CONCLUSIONS: Our results suggest that QCEA can reduce incision numbness, facial edema, and scar length, thereby improving the QoL of patients.

Endovascular Therapy of a Giant Renal Artery Aneurysm Combined With High-Flow Renal Arteriovenous Fistula Using a Patent Ductus Arteriosus Occluder.

Renal artery aneurysm (RAA) concomitant with a renal arteriovenous fistula (RAVF) is extremely rare. A 32-year-old man suffered from a giant RAA combined with high-flow RAVF. The computer tomographic angiography (CTA) demonstrated a RAA, which is 6.3 cm in length and 2.1 cm in diameter, combined with an arteriovenous fistula between the right renal artery and right renal vein (fistula area:1.05 cm × 1.0 cm). After a comprehensive preoperative assessment, a patent ductus arteriosus occluder (PDAO) was implanted. At a 1-year follow-up, the CTA study showed that the PDAO was in situ and there was no recanalization of the lesion. At a third-year follow-up, ultrasound examination showed an image of right renal atrophy. The results of long-term follow-up demonstrate that PDAO is safe and effective for the management of RAAs combined with high-flow RAVF.

Hybrid Surgery for Nontaper or Nonstump Lesions in Symptomatic Subacute or Chronic Internal Carotid Occlusion: A Better Solution.

BACKGROUND: Internal carotid artery occlusion (ICAO) causes transient ischemic attack and cerebral infarction. ICAO management remains clinically challenging. We discuss a hybrid treatment combining carotid endarterectomy and endovascular intervention (E-I) for patients with nontaper or nonstump lesions of symptomatic ICAO. METHODS: We treated 32 patients with consecutive nontaper or nonstump ICAO with neurological symptoms with hybrid treatment or E-I. We analyzed the epidemiology, symptoms, angiographic morphology, technical success rate, and perioperative complications. RESULTS: Of the 32 patients, 17 were treated with hybrid surgery and 15, E-I. The demographic data and lesion characteristics were similar between the 2 groups. The overall recanalization success rate was 71.9%. The rate for hybrid surgery was better than that for E-I (88.2% vs. 53.3%). The postoperative cerebral hyperperfusion rate showed no difference between the 2 groups (11.8% vs. 6.7%). Ipsilateral cerebral perfusion improved after treatment. The mean transition time and time to peak were greater than normal (normal values, <6 seconds and <8 seconds, respectively). Both increased significantly after treatment (mean transition time, 11.30 seconds vs. 7.25 seconds; time to peak, 19.30 seconds vs. 15.50 seconds). The incidence of perioperative complications from hybrid surgery was less than that with E-I (5.9% vs. 40.0%). Recurrent cerebrovascular events (5.9% vs. 13.3%) and the 3-month modified Rankin scale score (2.76 ± 0.66 vs. 2.93 ± 0.70) did not differ between the 2 groups. CONCLUSIONS: Recanalization of nontaper or nonstump ICAO with hybrid treatment was more successful than that with E-I, with fewer perioperative complications. The carotid endarterectomy procedure enables easier wire crossing across the occlusion and reduces potential technology-related complications by requiring a shorter lesion and fewer dissections and minimizing the effect of calcification.

Ankylosing Spondylitis Manifested by Extensive Cervical Erosions with Spontaneous Anterior Atlantoaxial Subluxation.

BACKGROUND: Atlantoaxial instability owing to bone erosions in a patient with ankylosing spondylitis (AS) is rare. We describe the radiographic characteristics, pathology, and treatment of a patient with this rare clinical manifestation and review the literature. CASE DESCRIPTION: A 36-year-old man with an 8-year history of AS presented with progressive neck pain, low back pain, hand numbness, and limited mobility of the neck. Cervical radiography showed anterior atlantoaxial subluxation with bone erosions at the odontoid process and a mass lateral to the atlas and edge of vertebrae. AS was diagnosed according to the modified New York criteria, and the patient underwent a posterior C0-C6 occipitocervical arthrodesis surgery and C3-C6 laminectomy to reconstruct atlantoaxial stability and relieve cervical compression. The symptoms of neck pain and hand numbness improved at the 1-year follow-up, and the patient completely resumed normal activities. Imaging showed realignment of C1-2 with complete decompression of the spinal cord and fusion of the atlantooccipital joint. The internal fixation has remained stable, and progressive bone erosion changes were not found after surgery. CONCLUSIONS: Extensive cervical erosions with spontaneous atlantoaxial subluxation in AS is extremely rare. The erosive change of atlantoaxial bone may be an early feature of AS. Cervical spine radiographs are essential for patients with AS who present with neck pain. Complete decompression and internal fixation are necessary to prevent serious neurologic morbidity from spinal cord injury in such patients.

Matrix metalloproteinases are regulated by MicroRNA 320 in macrophages and are associated with aortic dissection.

Aortic dissection (AD) is the circumferential or transversal tear of the aorta wall that allows blood to infiltrate the layers. MicroRNA (miR) analyses have demonstrated a correlation between miR-320 family and AD. The underlying mechanism is yet unclear. The matrix metalloproteinases (MMPs) are a group of proteolytic enzymes that could catalyze the degeneration of the extracellular matrix and the destruction of the vasculature. In this study, we investigated whether miR-320 presented a role in regulating the production of MMPs in aortic dissection. In a cohort of 30 CE patients and 30 healthy controls, the transcription and secretion of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, and MMP-12 by monocytes were investigated. The monocyte from AD patients presented significantly elevated capacity of MMP expression than those from healthy controls. In contrast, the monocyte/macrophage expression of miR-320 was significantly lower in AD patients than in controls. In both AD patients and healthy controls, LPS-activation of macrophages resulted in MMP upregulation and miR-320 downregulation, in which the MMP expression was significantly higher while the miR-320 expression was significantly lower in AD patients than in healthy controls. Transfection of miR-320 mimic did not affect MMP gene transcription but significantly reduced the protein production in some MMPs, demonstrated that miR-320 were involved in the post-transcriptional regulation of MMPs. Together, these results demonstrated that miR-320 could regulate the expression of MMPs by macrophages, through which miR-320 may interfere with AD development.

Rapamycin: A Bacteria-Derived Immunosuppressant That Has Anti-atherosclerotic Effects and Its Clinical Application.

Atherosclerosis (AS) is the leading cause of stroke and death worldwide. Although many lipid-lowering or antiplatelet medicines have been used to prevent the devastating outcomes caused by AS, the serious side effects of these medicines cannot be ignored. Moreover, these medicines are aimed at preventing end-point events rather than addressing the formation and progression of the lesion. Rapamycin (sirolimus), a fermentation product derived from soil samples, has immunosuppressive and anti-proliferation effects. It is an inhibitor of mammalian targets of rapamycin, thereby stimulating autophagy pathways. Several lines of evidence have demonstrated that rapamycin possess multiple protective effects against AS through various molecular mechanisms. Moreover, it has been used successfully as an anti-proliferation agent to prevent in-stent restenosis or vascular graft stenosis in patients with coronary artery disease. A thorough understanding of the biomedical regulatory mechanism of rapamycin in AS might reveal pathways for retarding AS. This review summarizes the current knowledge of biomedical mechanisms by which rapamycin retards AS through action on various cells (endothelial cells, macrophages, vascular smooth muscle cells, and T-cells) in early and advanced AS and describes clinical and potential clinical applications of the agent.

Transcriptome sequencing revealed candidate genes relevant to mesenchymal stem cells' role in aortic dissection patients.

Aortic dissection (AD) results from the imbalance between synthesis and degradation of extracellular matrices in aortic wall, which is characterized by chronic inflammation. Mesenchymal stem cells (MSCs) are known for anti­inflammatory and repairing effects and have therefore been studied for treatment for numerous diseases, including AD. However, it is unclear which genes or signaling pathways contribute to MSCs' role in AD. In the present study, RNA sequencing (RNA­seq) was conducted between MSCs from patients with AS (AD­MSCs) and those from age­matched healthy donors (HD­MSCs). RNA­seq revealed 201 differentially expressed genes (DEGs) under the filter of fold change>2 and P­value <0.05, in which 93 genes were upregulated and 108 downregulated. We selectively verified 9 out of 201 DEGs via reverse transcription­quantitative polymerase chain reaction (RT­qPCR) with an enlarged sample size. The trends of RT­qPCR results were consistent with RNA­seq data. Unsupervised hierarchical clustering of the 9­gene expression profiles enables the division of clinical samples into AD and HD groups. Kyoto Encyclopedia of Genes and Genomes analysis displayed a significant change in adhesion­related signaling pathways in AD­MSCs compared with HD­MSCs, whereas gene ontology analysis demonstrated DEGs were enriched in functions associated with development and morphogenesis, from a functional perspective. The present results indicate that gene expression profiles of AD­MSCs were significantly changed compared with HD­MSCs. These changes are probably associated with MSCs' adhesion capacity and development. These results may provide important insights into the role of MSCs in AD pathogenesis.

Heat shock protein 27 plays a protective role in thoracic aortic dissection by promoting cell proliferation and inhibiting apoptosis.

BACKGROUND: Thoracic aortic dissection (TAD) is one of the most severe aortic diseases. The study aimed to explore the potential role of heat shock protein 27 (HSP27) in the pathogenesis of TAD using an in vitro model of oxidative stress in vascular smooth muscle cells (VSMCs). METHODS: HSP27 was analyzed in aortic surgical specimens from 12 patients with TAD and 8 healthy controls. A lentiviral vector was used to overexpress HSP27 in rat aortic VSMCs. Cell proliferation and apoptosis were measured under oxidative stress induced by H2O2. RESULTS: HSP27 expression was significantly higher in aortic tissue from patients with TAD and VSMCs in the aortic media were the main cell type producing HSP27. Elevated oxidative stress was also detected in the TAD samples. Overexpression of HSP27 significantly attenuated H2O2-induced inhibition of cell proliferation. Furthermore, HSP27 was found to decrease H2O2-induced cell apoptosis and oxidative stress. CONCLUSIONS: These results suggest that HSP27 expression promotes VSMC viability, suppresses cell apoptosis, and confers protection against oxidative stress in TAD.

Critical Role of ADAMTS-4 in the Development of Sporadic Aortic Aneurysm and Dissection in Mice.

Sporadic aortic aneurysm and dissections (AADs) are common vascular diseases that carry a high mortality rate. ADAMTS-4 (a disintegrin-like and metalloproteinase with thrombospondin motifs-4) is a secreted proteinase involved in inflammation and matrix degradation. We previously showed ADAMTS-4 levels were increased in human sporadic descending thoracic AAD (TAAD) samples. Here, we provide evidence that ADAMTS-4 contributes to aortic destruction and sporadic AAD development. In a mouse model of sporadic AAD induced by a high-fat diet and angiotensin II infusion, ADAMTS-4 deficiency (Adamts-4-/-) significantly reduced challenge-induced aortic diameter enlargement, aneurysm formation, dissection and aortic rupture. Aortas in Adamts-4-/- mice showed reduced elastic fibre destruction, versican degradation, macrophage infiltration, and apoptosis. Interestingly, ADAMTS-4 was directly involved in smooth muscle cell (SMC) apoptosis. Under stress, ADAMTS-4 translocated to the nucleus in SMCs, especially in apoptotic SMCs. ADAMTS-4 directly cleaved and degraded poly ADP ribose polymerase-1 (a key molecule in DNA repair and cell survival), leading to SMC apoptosis. Finally, we showed significant ADAMTS-4 expression in aortic tissues from patients with sporadic ascending TAAD, particularly in SMCs. Our findings indicate that ADAMTS-4 induces SMC apoptosis, degrades versican, promotes inflammatory cell infiltration, and thus contributes to sporadic AAD development.

AKT2 Promotes Bone Marrow Cell-Mediated Aortic Protection in Mice.

BACKGROUND: Insufficient aortic protection and repair may contribute to the development of aortic aneurysms and dissections (AAD). However, mechanisms of aortic protection and repair are poorly understood. We have shown that the multifunctional kinase AKT2 plays an important role in protecting the aortic wall. Here, we examined whether AKT2 protects against AAD by promoting bone marrow cell (BMC)-mediated aortic protection. METHODS: Irradiated wild-type mice received green fluorescent protein-expressing BMCs from wild-type mice or Akt2(-/-) mice, followed by challenge with angiotensin II (1000 ng/kg/min) infusion for 4 weeks. We compared BMC recruitment, aortic destruction, and AAD development between groups. The direct effects of wild-type and Akt2(-/-) BMCs on smooth muscle cell survival were examined in coculture experiments. RESULTS: After angiotensin II infusion, no (0 of 14) wild-type BMC recipients had AAD; in contrast, 64% (9 of 14) of Akt2(-/-) BMC recipients had AAD (p = 0.002) with severe aortic destruction. Compared with aortas from challenged wild-type BMC recipients, aortas from challenged Akt2(-/-) BMC recipients showed significantly less BMC recruitment, NG2 (neuron-glial antigen 2) progenitor activation, and FSP1 (fibroblast-specific protein 1) fibroblast activation. In addition, aortas from challenged Akt2(-/-) BMC recipients showed increased apoptosis and inflammation. In coculture experiments, wild-type but not Akt2(-/-) BMCs prevented smooth muscle cells from undergoing oxidative stress-induced apoptosis. CONCLUSIONS: After aortic challenge, BMCs are recruited to the aortic wall and provide protection by activating progenitors and fibroblasts and by promoting aortic cell survival. Our findings indicate that AKT2 is involved in these processes and that defects in this pathway may promote progressive degeneration during AAD development.

NADPH oxidase 4 contributes to connective tissue growth factor expression through Smad3-dependent signaling pathway.

Transforming growth factor-ß (TGF-ß)/Smad signaling has been implicated in connective tissue growth factor (CTGF) expression in vascular smooth muscle cells (VSMC). Reactive oxygen species (ROS) are involved in activation of TGF-ß/Smad signaling. However, detailed mechanisms underlying the process remain unclear. In present study, we demonstrated TGF-ß1 strongly induced CTGF expression, Smad3 activation, NADPH oxidase 4 (Nox4) expression and increased ROS production in primary rat VSMC in vitro. NADPH oxidases inhibitor diphenylene iodonium (DPI) eliminated TGF-ß1-induced CTGF expression and ROS generation. In addition, small-interfering RNA (siRNA) silencing of Smad3 or Nox4 significantly suppressed TGF-ß1-mediated CTGF expression in VSMC. Furthermore, Nox4 silencing or inhibition eliminated TGF-ß1-induced Smad3 activation and interaction between Nox4 and Smad3. In vivo studies further identified a positive correlation of Nox4 levels with Smad3 activation and CTGF expression in atherosclerotic arteries of patients and animal models. These data established that a novel mechanistic link of Nox4-dependent activation of Smad3 to increased TGF-ß1-induced CTGF in the process of vascular remodeling, which suggested a new potential pathway for therapeutic interventions.