We developed multifunctional fluorescent nanoparticles suitable for the nonviral delivery of negatively charged molecules like RNA. Therefore, we incorporated the recently developed branched hCT-derived carrier peptide hCT(18-32)-k7 on the surface of luminescent quantum dots (QDs). Besides detailed characterization of our QD-peptide conjugates concerning stability, toxicity, and uptake mechanism. we used them for efficient RNA delivery into different cell lines. The results of our studies indicate the involvement of more than one endocytotic uptake pathway in the internalization process. Furthermore, we could show that the QD-peptide bioconjugates exhibit no effect on cell viability and possess high stability inside living cells. The efficacy of our newly designed constructs for oligonucleotide drug delivery is highlighted by the successful intracellular transport of Cy-3 labeled RNA. Moreover, by using the chemotherapeutic chloroquine the efficient release of the assemblies out of endosomes was demonstrated. These results prove that our multifunctional platforms are versatile tools for diagnostic and therapeutic imaging purposes applicable for biologically active siRNA or aptamer sequences.
Identification of target genes that mediate required functions downstream of transcription factors is hampered by the large number of genes whose expression changes when the factor is removed from a specific tissue and the numerous binding sites for the factor in the genome. Retinoic acid (RA) regulates transcription via RA receptors bound to RA response elements (RAREs) of which there are thousands in vertebrate genomes. Here, we combined chromatin immunoprecipitation sequencing (ChIP-seq) for epigenetic marks and RNA-seq on trunk tissue from wild-type and Aldh1a2-/-embryos lacking RA synthesis that exhibit body axis and forelimb defects. We identified a relatively small number of genes with altered expression when RA is missing that also have nearby RA-regulated deposition of histone H3 K27 acetylation (H3K27ac) (gene activation mark) or histone H3 K27 trimethylation (H3K27me3) (gene repression mark) associated with conserved RAREs, suggesting these genes function downstream of RA. RA-regulated epigenetic marks were identified near RA target genes already known to be required for body axis and limb formation, thus validating our approach; plus, many other candidate RA target genes were found. Nuclear receptor 2f1 (Nr2f1) and nuclear receptor 2f2 (Nr2f2) in addition to Meis homeobox 1 (Meis1) and Meis homeobox 2 (Meis2) gene family members were identified by our approach, and double knockouts of each family demonstrated previously unknown requirements for body axis and/or limb formation. A similar epigenetic approach can be used to determine the target genes for any transcriptional regulator for which a knockout is available.
Ghrelin is a unique bioactive peptide with respect to both the structure and its biological function. This 28-amino acid peptide is modified with an n-octanoyl group at serine-3, and accordingly is the only lipidated biologically active peptide hormone known so far. Ghrelin binds to the so-called ghrelin or GHS receptor, a member of the class A of G-protein coupled receptors, which leads to Ca(2+) release intracellularly due to the activation of the Gq-system. Interestingly, the ghrelin receptor shows a significant constitutive activity which means that in addition to agonists and antagonists, inverse agonists play an important role in receptor modulation. In this review, the major activities of ghrelin are summarized with a strong focus on the regulation of food intake. So far reported agonists, antagonists and inverse agonists are shown and structure activitiy relationships are discussed. Furthermore, the application of ghrelin ligands as novel anti-obesity drugs is outlined and the state of the art in this field is summarized.
Evidence is now emerging that early life environment can have lifelong effects on metabolic, cardiovascular, and pulmonary function in offspring, a concept also known as fetal or developmental programming. In mammals, developmental programming is thought to occur mainly via epigenetic mechanisms, which include DNA methylation, histone modifications, and expression of non-coding RNAs. The effects of developmental programming can be induced by the intrauterine environment, leading to intergenerational epigenetic effects from one generation to the next. Transgenerational epigenetic inheritance may be considered when developmental programming is transmitted across generations that were not exposed to the initial environment which triggered the change. So far, inter- and transgenerational programming has been mainly described for cardiovascular and metabolic disease risk. In this review, we discuss available evidence that epigenetic inheritance also occurs in respiratory diseases, using asthma and chronic obstructive pulmonary disease (COPD) as examples. While multiple epidemiological as well as animal studies demonstrate effects of ‘toxic’ intrauterine exposure on various asthma-related phenotypes in the offspring, only few studies link epigenetic marks to the observed phenotypes. As epigenetic marks may distinguish individuals most at risk of later disease at early age, it will enable early intervention strategies to reduce such risks. To achieve this goal further, well designed experimental and human studies are needed.
Prenatal exposure to tobacco smoke sex dependently influences methylation and mRNA levels of the Igf axis in lungs of mouse offspring Meyer, Karolin F; Krauss-Etschmann, Susanne; Kooistra, Wierd; Reinders-Luinge, Marjan; Timens, Wim; Kobzik, Lester; Plösch, Torsten; Hylkema, Machteld N Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Meyer, K. F., Krauss-Etschmann, S., Kooistra, W., Reinders-Luinge, M., Timens, W., Kobzik, L., ... Hylkema, M. N. (2017). Prenatal exposure to tobacco smoke sex dependently influences methylation and mRNA levels of the Igf axis in lungs of mouse offspring. American Journal of Physiology -Lung Cellular and Molecular Physiology, 312(4), L542-L555. https://doi.org/10.1152/ajplung.00271.2016 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Background: Prenatal smoke exposure is a risk factor for abnormal lung development and 33 increased sex-dependent susceptibility for asthma and COPD. Birth cohort studies show 34 genome-wide DNA methylation changes in children from smoking mothers, but evidence for 35 sex-dependent smoke-induced effects is limited. 36The insulin-like growth factor (IGF) system plays an important role in lung 37 development. We hypothesized that prenatal exposure to smoke induces lasting changes in 38 promoter methylation patterns of Igf1 and Igf1r, thus influencing transcriptional activity, and 39 contributing to abnormal lung development. 40Method: We measured and compared mRNA levels along with promoter methylation of Igf1 41 and Igf1r and their protein concentrations in lung tissue of 30-day-old mice which had been 42 prenatally exposed to cigarette smoke (PSE) or filtered air (control). Body weight at 30 days 43 after birth was measured as global indicator of normal development. 44Results: Female PSE mice showed lower mRNA levels of Igf1 and its receptor (Igf1: 45 p = 0.05; Igf1r: p = 0.03). Furthermore, CpG-site specific methylation changes were detected 46 in Igf1r in a sex-dependent manner and the body weight of female offspring was reduced after 47 prenatal exposure to smoke, while protein concentrations were unaffected. 48Conclusion: Prenatal exposure to smoke induces a CpG-site specific loss of Igf1r promoter 49 methylation, which can be associated with body weight. These findings highlight the 50 sex-dependent and potentially detrimental effects of in utero smoke exposure on DNA 51 methylation and Igf1 an...
The impact of prenatal smoke exposure (PSE) on DNA methylation has been demonstrated in blood samples from children of smoking mothers, but evidence for sex-dependent smoke-induced effects is limited. As the identified differentially methylated genes can be associated with developmental processes, and insulin-like growth factors (IGFs) play a critical role in prenatal tissue growth, we hypothesized that PSE induces fetal programming of Igf1r and Igf1. Using a mouse model of smoking during pregnancy, we show that PSE alters promoter methylation of Igf1r and Igf1 and deregulates their gene expression in lung and liver of fetal (E17.5) and neonatal (D3) mouse offspring. By further comparing female versus male, lung versus liver, or fetal versus neonatal time point, our results demonstrate that CpG site-specific aberrant methylation patterns sex-dependently vary per organ and time point. Moreover, PSE reduces gene expression of Igf1r and Igf1, dependent on organ, sex, and offspring's age. Our results indicate that PSE may be a source of organ-specific rather than general systemic fetal programming. This is exemplified here by gene promoter methylation and mRNA levels of Igf1r and Igf1, together with a sex- and organ-specific naturally established correlation of both parameters that is affected by prenatal smoke exposure. Moreover, the comparison of fetuses with neonates suggests a CpG site-dependent reversibility/persistence of PSE-induced differential methylation patterns.
Identification of target genes that mediate required functions downstream of transcription factors is hampered by the large number of genes whose expression changes when the factor is removed from a specific tissue and the numerous binding sites for the factor in the genome. Retinoic acid (RA) regulates transcription via RA receptors bound to RA response elements (RAREs) of which there are thousands in vertebrate genomes. Here, we combined ChIP-seq for epigenetic marks and RNA-seq on trunk tissue from wild-type and Aldh1a2-/-embryos lacking RA synthesis that exhibit body axis and forelimb defects. We identified a relatively small number of genes with altered expression when RA is missing that also have nearby RA-regulated deposition of H3K27ac (gene activation mark) or H3K27me3 (gene repression mark) associated with conserved RAREs, suggesting they have important downstream functions. RA-regulated epigenetic marks were identified near RA target genes already known to be required for body axis and limb formation, thus validating our approach, plus many other candidate RA target genes were found. Nr2f1, Nr2f2, Meis1, and Meis2 gene family members were identified by our approach, and double knockouts of each family demonstrated previously unknown requirements for body axis and/or limb formation. These findings demonstrate that our method for identifying RA-regulated epigenetic marks can be used to discover genes important for development.
Prenatal smoke exposure (PSE) is a risk factor for nicotine dependence. One susceptibility gene for nicotine dependence is Cytochrome P450 (CYP) 2A6, an enzyme responsible for the conversion of nicotine to cotinine and nicotine clearance in the liver. Higher activity of the CYP2A6 enzyme is associated with nicotine dependence, but no research has addressed the PSE effects on the CYP2A6 gene or its mouse homologue Cyp2a5 . We hypothesized that PSE affects Cyp2a5 promoter methylation, Cyp2a5 mRNA levels, and nicotine metabolism in offspring. We used a smoke-exposed pregnant mouse model. RNA, DNA, and microsomal protein were isolated from liver tissue of foetal, neonatal, and adult offspring. Enzyme activity, Cyp2a5 mRNA levels, and Cyp2a5 methylation status of six CpG sites within the promoter region were analysed via HPLC, RT-PCR, and bisulphite pyrosequencing. Our data show that PSE induced higher cotinine levels in livers of male neonatal and adult offspring compared to controls. PSE-induced cotinine levels in neonates correlated with Cyp2a5 mRNA expression and promoter methylation at CpG-7 and CpG+45. PSE increased methylation in almost all CpG sites in foetal offspring, and this effect persisted at CpG-74 in male neonatal and adult offspring. Our results indicate that male offspring of mothers which were exposed to cigarette smoke during pregnancy have a higher hepatic nicotine metabolism, which could be regulated by DNA methylation. Given the detected persistence into adulthood, extrapolation to the human situation suggests that sons born from smoking mothers could be more susceptible to nicotine dependence later in life.
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