SM22α (Smooth Muscle 22α) Prevents Aortic Aneurysm Formation by Inhibiting Smooth Muscle Cell Phenotypic Switching Through Suppressing Reactive Oxygen Species/NF-κB (Nuclear Factor-κB).

Objective- Vascular smooth muscle cell phenotypic transition plays a critical role in the formation of abdominal aortic aneurysms (AAAs). SM22α (smooth muscle 22α) has a vital role in maintaining the smooth muscle cell phenotype and is downregulated in AAA. However, whether manipulation of the SM22α gene influences the pathogenesis of AAA is unclear. Here, we investigated whether SM22α prevents AAA formation and explored the underlying mechanisms. Approach and Results- In both human and animal AAA tissues, a smooth muscle cell phenotypic switch was confirmed, as manifested by the downregulation of SM22α and α-SMA (α-smooth muscle actin) proteins. The methylation level of the SM22α gene promoter was dramatically higher in mouse AAA tissues than in control tissues. SM22α knockdown in ApoE-/- (apolipoprotein E-deficient) mice treated with Ang II (angiotensin II) accelerated the formation of AAAs, as evidenced by a larger maximal aortic diameter and more medial elastin degradation than those found in control mice, whereas SM22α overexpression exerted opposite effects. Similar results were obtained in a calcium chloride-induced mouse AAA model. Mechanistically, SM22α deficiency significantly increased reactive oxygen species production and NF-κB (nuclear factor-κB) activation in AAA tissues, whereas SM22α overexpression produced opposite effects. NF-κB antagonist SN50 or antioxidant N-acetyl-L-cysteine partially abrogated the exacerbating effects of SM22α silencing on AAA formation. Conclusions- SM22α reduction in AAAs because of the SM22α promoter hypermethylation accelerates AAA formation through the reactive oxygen species/NF-κB pathway, and therapeutic approaches to increase SM22α expression are potentially beneficial for preventing AAA formation.

Suppression of miRNA let-7i-5p promotes cardiomyocyte proliferation and repairs heart function post injury by targetting CCND2 and E2F2.

MiRNAs regulate the cardiomyocyte (CM) cell cycle at the post-transcriptional level, affect cell proliferation, and intervene in harmed CM repair post-injury. The present study was undertaken to characterize the role of let-7i-5p in the processes of CM cell cycle and proliferation and to reveal the mechanisms thereof. In the present study, we used real-time qPCR (RT-qPCR) to determine the up-regulated let-7i-5p in CMs during the postnatal switch from proliferation to terminal differentiation and further validated the role of let-7i-5p by loss- and gain-of-function of let-7i-5p in CMs in vitro and in vivo We found that the overexpression of let-7i-5p inhibited CM proliferation, whereas the suppression of let-7i-5p significantly facilitated CM proliferation. E2F2 and CCND2 were identified as the targets of let-7i-5p, mediating its effect in regulating the cell cycle of CMs. Supperession of let-7i-5p promoted the recovery of heart function post-myocardial infarction by enhancing E2F2 and CCND2. Collectively, our results revealed that let-7i-5p is involved in the regulation of the CM cell cycle and further impacts proliferation, which may offer a new potential therapeutic strategy for cardiac repair after ischemic injury.

The pseudogene PTENP1 regulates smooth muscle cells as a competing endogenous RNA.

The long non-coding RNA (lncRNA) PTENP1 is a pseudogene of phosphatase and tensin homologue deleted on chromosome ten (PTEN), has been implicated in smooth muscle cell (SMC) proliferation and apoptosis. PTENP1 is the pseudogene of PTEN. However, it is unclear whether and how PTENP1 functions in the proliferation and apoptosis of human aortic SMCs (HASMCs). Here, we hypothesised that PTENP1 inhibits HASMC proliferation and enhances apoptosis by promoting PTEN expression. PCR analysis and Western blot assays respectively showed that both PTENP1 and PTEN were up-regulated in human aortic dissection (AD) samples. PTENP1 overexpression significantly increased the protein expression of PTEN, promoted apoptosis and inhibited the proliferation of HASMCs. PTENP1 silencing exhibited the opposite effects and mitigated H2O2-induced apoptosis of HASMCs. In an angiotensin II (Ang II)-induced mouse aortic aneurysm (AA) model, PTENP1 overexpression potentiated aortic SMC apoptosis, exacerbated aneurysm formation. Mechanistically, RNA pull-down assay and a series of luciferase reporter assays using miR-21 mimics or inhibitors identified PTENP1 as a molecular sponge for miR-21 to endogenously compete for the binding between miR-21 and the PTEN transcript, releasing PTEN expression. This finding was further supported by in vitro immunofluorescent evidence showing decreased cell apoptosis upon miR-21 mimic administration under baseline PTENP1 overexpression. Ex vivo rescue of PTEN significantly mitigated the SMC apoptosis induced by PTENP1 overexpression. Finally, Western blot assays showed substantially reduced Akt phosphorylation and cyclin D1 and cyclin E levels with up-regulated PTENP1 in HASMCs. Our study identified PTENP1 as a mediator of HASMC homeostasis and suggests that PTENP1 is a potential target in AD or AA intervention.

The poor performance of cardiovascular risk scores in identifying patients with idiopathic inflammatory myopathies at high cardiovascular risk.

Framingham risk score (FRS), systematic coronary risk evaluation (SCORE), the 10-year atherosclerotic cardiovascular disease risk algorithm (ASCVD), and their modified risk scores are the most common cardiovascular risk scores. The aim of this case-control study was to evaluate the performance of cardiovascular risk scores in detecting carotid subclinical atherosclerosis (SCA) in patients with idiopathic inflammatory myopathies (IIMs). A total of 123 IIMs patients (71.5% female, mean age 50 ± 14 years) and 123 age- and gender-matched healthy controls were included in this study. Carotid SCA was more prevalent in IIMs patients compared with controls (77.2 vs 50.4%, P < 0.001). Moreover, patients with carotid SCA+ had older age, and all risk scores were significantly higher in IIMs patients with SCA+ compared to subjects with SCA- (all P < 0.001). According to FRS, SCORE, and ASCVD risk scores, 77.9, 96.8, and 66.7% patients with SCA+ were classified as low risk category, respectively. The modified scores also demonstrated a modest improvement in sensitivity. Notably, by adopting the optimal cutoff values, these risk scores had good discrimination on patients with SCA+, with area under curves of 0.802-0.893. In conclusion, all cardiovascular risk scores had a poor performance in identifying IIMs patients at high cardiovascular risk.

Association between vitamin D and latent tuberculosis infection in the United States: NHANES, 2011-2012.

BACKGROUND: Latent tuberculosis infection (LTBI) is a precursor of active tuberculosis diseases and an important issue in the United States and worldwide. The association between vitamin D deficiency and LTBI is poorly understood. METHODS: From 2011 to 2012, the National Health and Nutrition Examination Survey (NHANES) assessed LTBI (according to tuberculin skin testing and QuantiFERON®-TB Gold In-Tube) and measured serum levels of vitamin D. We evaluated the association between LTBI and vitamin D using multivariate logistic regression models adjusted for known confounders. RESULTS: The LTBI group had a lower 25-hydroxyvitamin D [25(OH)D] level than the non-LTBI group (p=0.0012). The adjusted risk of LTBI was significantly higher among participants with serum 25(OH)D levels <12 ng/ml (adjusted OR [aOR], 2.27; 95% CI, 1.40-3.66) and 12-19 ng/ml (aOR, 1.75; 95% CI, 1.25-2.46) compared to those with a level ≥30 ng/ml. The higher risk of LTBI among the participants with serum 25(OH)D levels <12 ng/ml and 12-19 ng/ml remained unchanged in both male and summer season subgroups. CONCLUSIONS: A low serum 25(OH)D level was significantly associated with the risk of LTBI in this US cohort.

Sirt1 Antisense Long Noncoding RNA Promotes Cardiomyocyte Proliferation by Enhancing the Stability of Sirt1.

Background Antisense long noncoding RNAs (lnc RNA s) are single-stranded RNA s that overlapped gene-coding regions on the opposite DNA strand and play as critical regulators in cardiovascular diseases. The high conservation and stability may be good advantages for antisense lnc RNA s. However, the roles of antisense lnc RNA s in cardiomyocyte proliferation and cardiac regeneration are still unknown. Methods and Results In this study, we found that Silent information regulator factor 2 related enzyme 1 (Sirt1) antisense lnc RNA expression was significantly increased during heart development. By gain and loss function of Sirt1 antisense lnc RNA using adenovirus and locked nucleic acid, respectively, we demonstrated that Sirt1 antisense lnc RNA promoted cardiomyocyte proliferation in vitro and in vivo, and the suppression of Sirt1 antisense lnc RNA inhibited cardiomyocyte proliferation. Moreover, overexpression of Sirt1 antisense lnc RNA enhanced cardiomyocyte proliferation, attenuated cardiomyocyte apoptosis, improved cardiac function, and decreased mortality rate after myocardial infarction. Furthermore, Sirt1 antisense lnc RNA can bind the Sirt1 3'-untranslated region, enhancing the stability of Sirt1 and increasing Sirt1 abundance at both the mRNA and protein levels. Finally, we found that Sirt1 was involved in Sirt1 antisense lnc RNA -induced cardiomyocyte proliferation. Conclusions The present study identified Sirt1 antisense lnc RNA as a novel regulator of cardiomyocyte proliferation and cardiac regeneration by interacting and stabilizing Sirt1 mRNA , which may serve as an effective gene target for preventing myocardial infarction.

Assessment of Thrombotic Risk in Atrial Fibrillation with Ultrasound Molecular Imaging of P-Selectin.

Molecular imaging of inflammatory mediators in atria may contribute to thrombotic risk assessment of atrial fibrillation (AF). We investigated the feasibility of ultrasound molecular imaging (UMI) targeted to P-selectin to assess thrombotic risk in AF. Rat AF models were established with rapid atrial pacing. Microbubbles targeted to P-selectin were injected into the rats, followed by left atrial (LA) UMI examination. Furthermore, P-selectin, platelets (PLTs), fibrin and tissue factor (TF) of LA were detected by histopathology and scanning electron microscopy. Plasma levels of P-selectin, thrombin-antithrombin complex (TAT) and prothrombin fragment 1 + 2 (F1 + 2) were measured by enzyme-linked immunosorbent assay. The data showed that P-selectin in LA was correlated with PLT, fibrin and TF (r = 0.735, p < 0.05; r = 0.827, p < 0.05; r = 0.785, p < 0.05, respectively). The plasma level of P-selectin was correlated with the expression of TAT and F1 + 2 (r = 0.866, p < 0.05; r = 0.916, p < 0.05, respectively). The contrast video intensity of adhered microbubbles targeted to P-selectin was correlated with the levels of P-selectin, PLT and fibrin in LA (r = 0.768, p < 0.05; r = 0.798, p < 0.05; r = 0.745, p < 0.05, respectively). In conclusion, P-selectin may serve as a biomarker for thrombotic risk in AF and can be quantified by UMI to assess thrombotic risk.

Risk factors for infective endocarditis in children with congenital heart diseases - A nationwide population-based case control study.

BACKGROUND: Infective endocarditis (IE) is uncommon in childhood. Its associated epidemiological characteristics in patients with congenital heart disease (CHD) remain unclear. METHODS: The study population included children born in Taiwan during the years 1997 to 2005 who were diagnosed as having CHD before 3years of age. All children were followed up until the end year of 2010, the diagnosis of infective endocarditis, or death. The demographic characteristics of patients with and without IE, the invasive procedures performed during 6months before the index date, the prophylactic antibiotics related to dental procedures, and in-hospital mortality were collected. RESULTS: Information of 24,729 children with CHD were retrieved for our analysis and 237 patients with newly diagnosed IE were identified. The incidence rate of IE in all CHD lesions was 11.13 per 10,000person-years. Taking ASD for reference, the following CHD lesions were at risk for IE: cyanotic CHD (adjusted OR, 9.58; 95% confidence interval, 5.38-17.05), endocardial cushion defect (ECD) (8.01; 2.73-23.50), Left-sided lesions (4.36; 1.90-10.01) and VSD (2.93; 1.64-5.23). Patients who underwent procedures have a higher risk of acquiring IE which include central venous catheter (CVC) insertion (3.17; 2.36-4.27), cardiac catheterization (3.74; 2.67-5.22), open-heart surgery (2.47; 1.61-3.77), valve surgery (3.20; 1.70-6.02), and shunt surgery (7.43; 2.36-23.41). However, dental procedures did not increase the risk of IE, irrespective of antibiotic usage. CONCLUSIONS: The risk of IE varies markedly among CHD lesions in our study. Invasive heart procedures but not dental procedures, are more significantly associated with IE among children with CHD.