Search

We hypothesized that epigenetics is a link between smoking/allergen exposures and the development of Asthma and chronic obstructive pulmonary disease (ACO). A total of 75 of 228 COPD patients were identified as ACO, which was independently associated with increased exacerbations. Microarray analysis identified 404 differentially methylated loci (DML) in ACO patients, and 6575 DML in those with rapid lung function decline in a discovery cohort. In the validation cohort, ACO patients had hypermethylated PDE9A (+ 30,088)/ZNF323 (− 296), and hypomethylated SEPT8 (− 47) genes as compared with either pure COPD patients or healthy non-smokers. Hypermethylated TIGIT (− 173) gene and hypomethylated CYSLTR1 (+ 348)/CCDC88C (+ 125,722)/ADORA2B (+ 1339) were associated with severe airflow limitation, while hypomethylated IFRD1 (− 515) gene with frequent exacerbation in all the COPD patients. Hypermethylated ZNF323 (− 296) / MPV17L (+ 194) and hypomethylated PTPRN2 (+ 10,000) genes were associated with rapid lung function decline. In vitro cigarette smoke extract and ovalbumin concurrent exposure resulted in specific DNA methylation changes of the MPV17L / ZNF323 genes, while 5-aza-2′-deoxycytidine treatment reversed promoter hypermethylation-mediated MPV17L under-expression accompanied with reduced apoptosis and decreased generation of reactive oxygen species. Aberrant DNA methylations may constitute a determinant for ACO, and provide a biomarker of airflow limitation, exacerbation, and lung function decline. [ABSTRACT FROM AUTHOR]

Platelet-derived growth factor ( PDGF) can promote vascular smooth muscle cells ( VSMCs) to switch from the quiescent contractile phenotype to synthetic phenotype, which contributes to atherosclerosis. We aimed to investigate the role of micro RNA let-7g in phenotypic switching. Bioinformatics prediction was used to find let-7g target genes in the PDGF/mitogen-activated protein kinase kinase kinase 1 ( MEKK1)/extracellular signal-regulated kinase ( ERK)/Krüppel-like factor-4 ( KLF4) signalling pathway that affects VSMC phenotypic switching. The luciferase reporter assay and let-7g transfection were used to confirm let-7g target genes. Two contractile proteins alpha-smooth muscle actin (α- SMA) and calponin were VSMC-specific genes and were measured as the indicators for VSMC phenotype. Lentivirus carrying the let-7g gene was injected to apolipoprotein E knockout (apoE−/−) mice to confirm let-7g's effect on preventing atherosclerosis. Through the PDGF/ MEKK1/ ERK/ KLF4 signalling pathway, PDGF- BB can inhibit α- SMA and calponin. The PDGFB and MEKK1 genes were predicted to harbour let-7g binding sites, which were confirmed by our reporter assays. Transfection of let-7g to VSMC also reduced PDGFB and MEKK1 levels. Moreover, we showed that let-7g decreased phosphorylated- ERK1/2 while had no effect on total ERK1/2. KLF4 can reduce VSMC-specific gene expression by preventing myocardin-serum response factor ( SRF) complex from associating with these gene promoters. The immunoprecipitation assay showed that let-7g decreased the interaction between KLF4 and SRF. Further experiments demonstrated that let-7g can increase α- SMA and calponin levels to maintain VSMC in the contractile status. Injection of lentivirus carrying let-7g gene increased let-7g's levels in aorta and significantly decreased atherosclerotic plaques in the apoE−/− mice. We demonstrated that let-7g reduces the PDGF/ MEKK1/ ERK/ KLF4 signalling to maintain VSMC in the contractile status, which further reduce VSMC atherosclerotic change. [ABSTRACT FROM AUTHOR]

Peripheral artery disease ( PAD) is a manifestation of systemic atherosclerosis and conveys a significant health burden globally. Critical limb ischaemia encompasses the most severe consequence of PAD. Our previous studies indicate that micro RNA let-7g prevents atherosclerosis and improves endothelial functions. This study aimed to investigate whether and how let-7g therapy may improve blood flow to ischaemic limbs. The present study shows that let-7g has multiple pro-angiogenic effects on mouse ischaemic limb model and could be a potential therapeutic agent for PAD. Mice receiving intramuscular injection of let-7g had more neovascularization, better local perfusion and increased recruitment of endothelial progenitor cells after hindlimb ischaemia. The therapeutic effects of let-7g's on angiogenesis are mediated by multiple regulatory machinery. First, let-7g increased expression of vascular endothelial growth factor-A ( VEGF-A) and VEGF receptor-2 ( VEGFR-2) through targeting their upstream regulators HIF-3α and TP53. In addition, let-7g affected the splicing factor SC35 which subsequently enhanced the alternative splicing of VEGF-A from the anti-angiogenic isoform VEGF-A165b towards the pro-angiogenic isoform VEGF-A164a. The pleiotropic effects of let-7g on angiogenesis imply that let-7g may possess a therapeutic potential in ischaemic diseases. [ABSTRACT FROM AUTHOR]

Background: FPR1 over-expression and insufficiency of FPR2 and FPR3 are associated with disease severity of obstructive sleep apnea (OSA). We hypothesized that epigenetic modification of the FPR1/2/3 genes may underlie intermittent hypoxia with re-oxygenation (IHR) injury in OSA., Methods: DNA methylation levels over 17 CpG sites of the FPR1/2/3 genes and their gene expression levels in the peripheral blood mononuclear cells were determined in 40 treatment-naïve OSA patients, 12 severe OSA patients under long-term continuous positive airway pressure treatment, 16 primary snoring (PS) subjects, and 10 healthy non-snorers (HS)., Results: Both -524 and -264 CpG sites of the FPR1 gene were hypomethylated in treatment-naïve OSA versus HS, while -264 CpG site methylation level was negatively correlated with FPR1/FPR3 gene expression ratio and associated with prevalent diabetes mellitus. Both +8802 and +8845 CpG sites of the FPR2 gene were hypermethylated in treatment-naive OSA versus HS, while hypermethylated +9132 and +9150 CpG sites were both associated with prevalent hypertension. FPR3 gene expression and DNA methylation levels over -842/-516 CpG sites of the FPR3 gene were both decreased in treatment-naive OSA versus HS, while hypermethylated -429 CpG site was associated with elevated serum C-reactive protein level. In vitro IHR stimuli in human monocytic THP-1 cells resulted in gene promoter hypomethylation-mediated FPR1 over-expression, increased production of reactive oxygen species, and increased cell apoptosis, which could be reversed with re-methylation agent, folic acid, treatment., Conclusions: Aberrant DNA methylation patterns of the FPR1/2/3 gene promoters contribute to disease severity and diabetes mellitus or cardiovascular disease in OSA patients, probably through regulating FPR1/2/3 gene expressions., Competing Interests: None., (AJTR Copyright © 2020.)

Tissue plasminogen activator is the only U.S. FDA-approved therapy for ischemic stroke, while there is no specific medication for hemorrhagic stroke. Therefore, the treatment of acute stroke continues to be a major unmet clinical need. We explored the effects of miR-195 on neurovascular protection and its potential in treating acute stroke. Using both cellular and animal studies, we showed that miR-195's beneficial effects are mediated by four mechanisms: (1) anti-apoptosis for injured neural cells by directly suppressing Sema3A/Cdc42/JNK signaling, (2) neural regeneration by promoting neural stem cell proliferation and migration, (3) anti-inflammation by directly blocking the NF-kB pathway, and (4) improvement of endothelial functions. We intravenously injected miR-195 carried by nanoparticles into rats with either ischemic or hemorrhagic stroke in the acute stage. The results showed that miR-195 reduced the size of brain damage and improved functional recovery in both types of stroke rats. The reduction of injured brain volume could be up to 45% in ischemic stroke and approximately 30% in hemorrhagic stroke. The therapeutic window between stroke onset and miR-195 treatment could be up to 6 h. Our data demonstrated that miR-195 possesses the potential to become a new drug to treat acute ischemic and hemorrhagic stroke.

Peripheral artery disease (PAD) is a manifestation of systemic atherosclerosis and conveys a significant health burden globally. Critical limb ischaemia encompasses the most severe consequence of PAD. Our previous studies indicate that microRNA let-7g prevents atherosclerosis and improves endothelial functions. This study aimed to investigate whether and how let-7g therapy may improve blood flow to ischaemic limbs. The present study shows that let-7g has multiple pro-angiogenic effects on mouse ischaemic limb model and could be a potential therapeutic agent for PAD. Mice receiving intramuscular injection of let-7g had more neovascularization, better local perfusion and increased recruitment of endothelial progenitor cells after hindlimb ischaemia. The therapeutic effects of let-7g's on angiogenesis are mediated by multiple regulatory machinery. First, let-7g increased expression of vascular endothelial growth factor-A (VEGF-A) and VEGF receptor-2 (VEGFR-2) through targeting their upstream regulators HIF-3α and TP53. In addition, let-7g affected the splicing factor SC35 which subsequently enhanced the alternative splicing of VEGF-A from the anti-angiogenic isoform VEGF-A 165b towards the pro-angiogenic isoform VEGF-A 164a . The pleiotropic effects of let-7g on angiogenesis imply that let-7g may possess a therapeutic potential in ischaemic diseases., (© 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)