Role of noncoding RNA in vascular remodelling

Purpose of review: Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are becoming fundamentally important in the pathophysiology relating to injury-induced vascular remodelling. We highlight recent studies that demonstrate the involvement of ncRNAs in vein graft disease, in in-stent restenosis and in pulmonary arterial hypertension, with a particular focus on endothelial cell and vascular smooth muscle cell function. We also briefly discuss the emerging role of exosomal-derived ncRNAs and how this mechanism impacts on vascular function. Recent findings: ncRNAs have been described as novel regulators in the pathophysiology of vascular injury, inflammation, and vessel wall remodelling. In particular, several studies have demonstrated that manipulation of miRNAs can reduce the burden of pathological vascular remodelling. Such studies have also shown that exosomal miRNA-mediated, cell-to-cell communication between endothelial cells and vascular smooth muscle cells is critical in the disease process. In addition to miRNAs, lncRNAs are emerging as regulators of vascular function in health and disease. Although lncRNAs are complex in both their sheer numbers and mechanisms of action, identifying their contribution to vascular disease is essential. Summary: Given the important roles of ncRNAs in vascular injury and remodelling together will their capacity for cell-to-cell communication, manipulating ncRNA might provide novel therapeutic interventions

Estimating the burden of disease attributable to indoor air pollution from household use of solid fuels in South Africa in 2000

Objectives. To estimate the burden of respiratory ill health in South African children and adults in 2000 from exposure to indoor air pollution associated with household use of solid fuels.Design. World Health Organization comparative risk assessment (CRA) methodology was followed. The South African Census 2001 was used to derive the proportion of households using solid fuels for cooking and heating by population group. Exposure estimates were adjusted by a ventilation factor taking into account the general level of ventilation in the households. Population-attributable fractions were calculated and applied to revised burden of disease estimates for each population group. Monte Carlo simulation-modelling techniques were used for uncertainty analysis.Setting. South Africa.Subjects. Black African, coloured, white and Indian children under 5 years of age and adults aged 30 years and older.Outcome measures. Mortality and disability-adjusted life years (DALYs) from acute lower respiratory infections in children under 5 years, and chronic obstructive pulmonary disease and lung cancer in adults 30 years and older.Results. An estimated 20% of South African households were exposed to indoor smoke from solid fuels, with marked variation by population group. This exposure was estimated to have caused 2 489 deaths (95% uncertainty interval 1 672 - 3 324) or 0.5% (95% uncertainty interval 0.3 - 0.6%) of all deaths in South Africa in 2000. The loss of healthy life years comprised a slightly smaller proportion of the total: 60 934 DALYs (95% uncertainty interval 41 170 - 81 246) or 0.4% of all DALYs (95% uncertainty interval 0.3 - 0.5%) in South Africa in 2000. Almost 99% of this burden occurred in the black African population.Conclusions. The most important interventions to reduce this impact include access to cleaner household fuels, improved stoves, and better ventilation

Ultrasound and microbubble gene delivery for targeting altered placental microRNAs in preeclampsia

Ultrasound (US) and microbubble (MB) gene delivery has attracted growing interest as a clinically applicable gene therapy (GT). Though preclinical studies have investigated the system in various tissues, there is limited research in targeting the placenta. This is a potential therapeutic strategy for preeclampsia (PE), which has an underlying genetic basis and ineffective management strategies. Differentially expressed placental microRNAs (miRNAs) in PE may represent suitable targets for GT. Microbubbles (SonoVue) and plasmid (pGL3 or pGL4.13) were administered systemically to CD1 mice, followed by exposure of the heart to US (H14, 1.8 M.I., 1cm focal depth, 2 minutes), using Siemens Acuson Sequoia-512 system and 15L8 probe. Luciferase assays were performed to evaluate gene transfection. Significantly differentially expressed placental miRNAs in PE patients were identified as candidates based on detection by three or more screening studies. Expression of candidate miRNAs was measured by qRT-PCR in PE rat model placentas. In trial 1, low levels of luciferase activity were detected in the heart of treatment mouse 1, 2 and 3. In trial 2, luciferase activity was evident in the atria of treatment mouse 2. In trial 3, higher luciferase activity was detected in the ventricles of the treatment mouse and activity was also detected in the atria. The literature review identified eight candidate miRNAs. MiR-223 (1.46-fold increase) and miR-181a (0.81-fold decrease) were significantly differentially expressed in PE rat model placentas. MiR-223 and -181a may represent targets for US and MB gene delivery. Future studies will apply the US and MB gene delivery protocol for translation to targeting the placenta in our PE rodent model

Estimating the burden of disease attributable to lead exposure in South Africa in 2000

Objectives. To estimate the burden of disease attributable to lead exposure in South Africa in 2000.Design. World Health Organization comparative risk assessment (CRA) methodology was followed. Recent community studies were used to derive mean blood lead concentrations in adults and children in urban and rural areas. Population-attributable fractions were calculated and applied to revised burden of disease estimates for the relevant disease categories for South Africa in the year 2000. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis.Setting. South Africa.Subjects. Children under 5 and adults 30 years and older. Outcome measures. Cardiovascular mortality and disabilityadjusted life years (DALYs) in adults 30 years and older andmild mental disability DALYs in children under 5 years. Results. Lead exposure was estimated to cause 1 428 deaths (95% uncertainty interval 1 086-l 772) or 0.27% (95% uncertainty interval: 0.21 - 0.34%) of all deaths in South Africa in 2000. Burden of disease attributed to lead exposure was dominated by mild mental disability in young children, accounting for 75% of the total 58 939 (95% uncertainty interval 55 413 - 62 500) attributable DALYs. Cardiovascular disease in adults accounted for the remainder of the burden.Conclusions. Even with the phasing out of leaded petrol, exposure to lead from its ongoing addition to paint, paraoccupational exposure and its use in backyard 'cottage industries' will continue to be an important public health hazard in South Africa for decades. Young children, especially those from disadvantaged communities, remain particularly vulnerable to lead exposure and poisoning

A novel triple-cell two-dimensional model to study immune-vascular interplay in atherosclerosis

Atherosclerosis is a complex inflammatory pathology underpinning cardiovascular diseases (CVD), which are the leading cause of death worldwide. The interplay between vascular stromal cells and immune cells is fundamental to the progression and outcome of atherosclerotic disease, however, the majority of in vitro studies do not consider the implications of these interactions and predominantly use mono-culture approaches. Here we present a simple and robust methodology involving the co-culture of vascular endothelial (ECs) and smooth muscle cells (SMCs) alongside an inflammatory compartment, in our study containing THP-1 macrophages, for studying these complex interactions. Using this approach, we demonstrate that the interaction between vascular stromal and immune cells produces unique cellular phenotypes and soluble mediator profiles not observed in double-cell 2D cultures. Our results highlight the importance of cellular communication and support the growing idea that in vitro research must evolve from mono-culture systems to provide data more representative of the multi-cellular environment found in vivo. The methodology presented, in comparison with established approaches, has the advantage of being technically simple whilst enabling the isolation of pure populations of ECs, SMCs and immune cells directly from the co-culture without cell sorting. The approach described within would be applicable to those studying mechanisms of vascular inflammation, particularly in relation to understanding the impact cellular interaction has on the cumulative immune-vascular response to atherogenic or inflammatory stimuli

Histone H3 lysine 9 trimethylation is required for suppressing the expression of an embryonically activated retrotransposon in Xenopus laevis.

Transposable elements in the genome are generally silenced in differentiated somatic cells. However, increasing evidence indicates that some of them are actively transcribed in early embryos and the proper regulation of retrotransposon expression is essential for normal development. Although their developmentally regulated expression has been shown, the mechanisms controlling retrotransposon expression in early embryos are still not well understood. Here, we observe a dynamic expression pattern of retrotransposons with three out of ten examined retrotransposons (1a11, λ-olt 2-1 and xretpos(L)) being transcribed solely during early embryonic development. We also identified a transcript that contains the long terminal repeat (LTR) of λ-olt 2-1 and shows a similar expression pattern to λ-olt 2-1 in early Xenopus embryos. All three retrotransposons are transcribed by RNA polymerase II. Although their expression levels decline during development, the LTRs are marked by histone H3 lysine 4 trimethylation. Furthermore, retrotransposons, especially λ-olt 2-1, are enriched with histone H3 lysine 9 trimethylation (H3K9me3) when their expression is repressed. Overexpression of lysine-specific demethylase 4d removes H3K9me3 marks from Xenopus embryos and inhibits the repression of λ-olt 2-1 after gastrulation. Thus, our study shows that H3K9me3 is important for silencing the developmentally regulated retrotransposon in Xenopus laevis.Gurdon laboratory is supported by grants from the Wellcome Trust (RG69899) and MRC to J.B.GThis is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/srep1423

TGFβ, smooth muscle cells and coronary artery disease: a review

Excessive vascular smooth muscle cell (SMC) proliferation, migration and extracellular matrix (ECM) synthesis are key events in the development of intimal hyperplasia, a pathophysiological response to acute or chronic sources of vascular damage that can lead to occlusive narrowing of the vessel lumen. Atherosclerosis, the primary cause of coronary artery disease, is characterised by chronic vascular inflammation and dyslipidemia, while revascularisation surgeries such as coronary stenting and bypass grafting represent acute forms of vascular injury. Gene knockouts of transforming growth factor-beta (TGFβ), its receptors and downstream signalling proteins have demonstrated the importance of this pleiotropic cytokine during vasculogenesis and in the maintenance of vascular homeostasis. Dysregulated TGFβ signalling is a hallmark of many vascular diseases, and has been associated with the induction of pathological vascular cell phenotypes, fibrosis and ECM remodelling. Here we present an overview of TGFβ signalling in SMCs, highlighting the ways in which this multifaceted cytokine regulates SMC behaviour and phenotype in cardiovascular diseases driven by intimal hyperplasia

Tropism-Modification Strategies for Targeted Gene Delivery Using Adenoviral Vectors

Achieving high efficiency, targeted gene delivery with adenoviral vectors is a long-standing goal in the field of clinical gene therapy. To achieve this, platform vectors must combine efficient retargeting strategies with detargeting modifications to ablate native receptor binding (i.e. CAR/integrins/heparan sulfate proteoglycans) and “bridging” interactions. “Bridging” interactions refer to coagulation factor binding, namely coagulation factor X (FX), which bridges hepatocyte transduction in vivo through engagement with surface expressed heparan sulfate proteoglycans (HSPGs). These interactions can contribute to the off-target sequestration of Ad5 in the liver and its characteristic dose-limiting hepatotoxicity, thereby significantly limiting the in vivo targeting efficiency and clinical potential of Ad5-based therapeutics. To date, various approaches to retargeting adenoviruses (Ad) have been described. These include genetic modification strategies to incorporate peptide ligands (within fiber knob domain, fiber shaft, penton base, pIX or hexon), pseudotyping of capsid proteins to include whole fiber substitutions or fiber knob chimeras, pseudotyping with non-human Ad species or with capsid proteins derived from other viral families, hexon hypervariable region (HVR) substitutions and adapter-based conjugation/crosslinking of scFv, growth factors or monoclonal antibodies directed against surface-expressed target antigens. In order to maximize retargeting, strategies which permit detargeting from undesirable interactions between the Ad capsid and components of the circulatory system (e.g. coagulation factors, erythrocytes, pre-existing neutralizing antibodies), can be employed simultaneously. Detargeting can be achieved by genetic ablation of native receptor-binding determinants, ablation of “bridging interactions” such as those which occur between the hexon of Ad5 and coagulation factor X (FX), or alternatively, through the use of polymer-coated “stealth” vectors which avoid these interactions. Simultaneous retargeting and detargeting can be achieved by combining multiple genetic and/or chemical modifications

Biodistribution and inflammatory profiles of novel penton and hexon double-mutant serotype 5 adenoviruses

The use of adenovirus serotype 5 (Ad5) vectors in the clinical setting is severely hampered by the profound liver tropism observed after intravascular delivery coupled with the pronounced inflammatory and innate immune response elicited by these vectors. Liver transduction by circulating Ad5 virions is mediated by a high-affinity interaction between the capsid hexon protein and blood coagulation factor X (FX), whilst penton-α(v)integrin interactions are thought to contribute to the induction of anti-Ad5 inflammatory and innate immune responses. To overcome these limitations, we sought to develop and characterise for the first time novel Ad5 vectors possessing mutations ablating both hexon:FX and penton:integrin interactions. As expected, intravascular administration of the FX binding-ablated Ad5HVR5*HVR7*E451Q vector (AdT*) resulted in significantly reduced liver transduction in vivo compared to Ad5. In macrophage-depleted mice, increased spleen uptake of AdT* was accompanied by an elevation in the levels of several inflammatory mediators. However ablation of the penton RGD motif in the AdT* vector background (AdT*RGE) resulted in a significant 5-fold reduction in spleen uptake and attenuated the antiviral inflammatory response. A reduction in spleen uptake and inflammatory activation was also observed in animals after intravascular administration of Ad5RGE compared to the parental Ad5 vector, with reduced co-localisation of the viral beta-galactosidase transgene with MAdCAM-1+ sinus-lining endothelial cells. Our detailed assessment of these novel adenoviruses indicates that penton base RGE mutation in combination with FX binding-ablation may be a viable strategy to attenuate the undesired liver uptake and pro-inflammatory responses to Ad5 vectors after intravascular deliver