Epigenetic bystander-like effects of stroke in somatic organs

Epigenetic-sensitive challenges of cardiohepatic interactions: clinical and therapeutic implications in heart failure patients

Heart failure and liver dysfunction can coexist owing to complex cardiohepatic interactions including the development of hypoxic hepatitis and congestive hepatopathy in patients with heart failure as well as 'cirrhotic cardiomyopathy' in advanced liver disease and following liver transplantation. The involvement of liver dysfunction in patients with heart failure reflects crucial systemic hemodynamic modifications occurring during the evolution of this syndrome. The arterial hypoperfusion and downstream hypoxia can lead to hypoxic hepatitis in acute heart failure patients whereas passive congestion is correlated with congestive hepatopathy occurring in patients with chronic heart failure. Nowadays, liquid biopsy strategies measuring liver function are well established in evaluating the prognosis of patients with heart failure. Large randomized clinical trials confirmed that gamma-glutamyltransferase, bilirubin, lactate deihydrogenase, and transaminases are useful prognostic biomarkers in patients with heart failure after transplantation. Deeper knowledge about the pathogenic mechanisms underlying cardiohepatic interactions would be useful to improve diagnosis, prognosis, and treatments of these comorbid patients. Epigenetic-sensitive modifications are heritable changes to gene expression without involving DNA sequence, comprising DNA methylation, histone modifications, and noncoding RNAs which seem to be relevant in the pathogenesis of heart failure and liver diseases when considered in a separate way. The goal of our review is to highlight the pertinence of detecting epigenetic modifications during the complex cardiohepatic interactions in clinical setting. Moreover, we propose a clinical research program which may be useful to identify epigenetic-sensitive biomarkers of cardiohepatic interactions and advance personalized therapy in these comorbid patients.

The progress of research on histone methylation in ischemic stroke pathogenesis

Stroke, also known as cerebral stroke or cerebrovascular accident, refers to acute ischemic or hemorrhagic encephalopathy caused by a disturbance to cerebral blood flow. Ischemic stroke is the most common type of cerebral stroke, accounting for approximately 80% of the total incidence of clinical stroke. High morbidity, disability, and mortality rates place heavy burdens on the families of patients and society. An increasing number of studies have shown that histone modification plays an important role in the pathogenesis of ischemic stroke, but most studies on histone modification focus on acetylation, and studies on the role of histone methylation in the pathogenesis of ischemic stroke are limited. Here, we review the role of histone methylation and related histone methyltransferase (HMT) inhibitors in the pathogenesis of ischemic stroke and related HMT inhibitors in the treatment of ischemic stroke, which may open up a new avenue to the study of ischemic stroke.

Identification of Dysregulated Mechanisms and Potential Biomarkers in Ischemic Stroke Onset

Objective

Ischemic stroke (IS) is a major cause of severe disability. This study aimed to identify potential biomarkers closely related to IS diagnosis and treatment.

Methods

Profiles of gene expression were obtained from datasets GSE16561, GSE22255, GSE112801 and GSE110993. Differentially expressed mRNAs between IS and controls were then subjected to weighted gene co-expression network analysis as well as multiscale embedded gene co-expression network analysis. The intersection of the two sets of module genes was subjected to analyses of functional enrichment and of microRNAs (miRNAs) regulation. Then, the area under receiver operating characteristic curves (AUC) was calculated to assess the ability of genes to discriminate IS patients from controls. IS diagnostic signatures were constructed using least absolute shrinkage and selection operator regression.

Results

A total of 234 common co-expression network genes were found to be potentially associated with IS. Enrichment analysis found that these genes were mainly associated with inflammation and immune response. The aberrantly expressed miRNAs (hsa-miR-651-5p, hsa-miR-138-5p, hsa-miR-9-3p and hsa-miR-374a-3p) in IS had regulatory effects on IS-related genes and were involved in brain-related diseases. We used the criterion AUC > 0.7 to screen out 23 hub genes from IS-related genes in the GSE16561 and GSE22255 datasets. We obtained an 8-gene signature (ADCY4, DUSP1, ATP5F1, DCTN5, EIF3G, ELAVL1, EXOSC7 and PPIE) from the training set of GSE16561 dataset, which we confirmed in the validation set of GSE16561 dataset and in the GSE22255 dataset. The genes in this signature were highly accurate for diagnosing IS. In addition, the 8-gene signature significantly correlated with infiltration by immune cells.

Conclusion

These findings provide new clues to molecular mechanisms and treatment targets in IS. The genes in the signature may be candidate markers and potential gene targets for treatments.

Histone 3 modifications and blood pressure in the Beijing Truck Driver Air Pollution Study

CONTEXT

Histone modifications regulate gene expression; dysregulation has been linked with cardiovascular diseases. Associations between histone modification levels and blood pressure in humans are unclear.

OBJECTIVE

We examine the relationship between global histone concentrations and various markers of blood pressure.

MATERIALS AND METHODS

Using the Beijing Truck Driver Air Pollution Study, we investigated global peripheral white blood cell histone modifications (H3K9ac, H3K9me3, H3K27me3, and H3K36me3) associations with pre- and post-work measurements of systolic (SBP) and diastolic (DBP) blood pressure, mean arterial pressure (MAP), and pulse pressure (PP) using multivariable mixed-effect models.

RESULTS

H3K9ac was negatively associated with pre-work SBP and MAP; H3K9me3 was negatively associated with pre-work SBP, DBP, and MAP; and H3K27me3 was negatively associated with pre-work SBP. Among office workers, H3K9me3 was negatively associated with pre-work SBP, DBP, and MAP. Among truck drivers, H3K9ac and H3K27me were negatively associated with pre-work SBP, and H3K27me3 was positively associated with post-work PP.

DISCUSSION AND CONCLUSION

Epigenome-wide H3K9ac, H3K9me3, and H3K27me3 were negatively associated with multiple pre-work blood pressure measures. These associations substantially changed during the day, suggesting an influence of daily activities. Blood-based histone modification biomarkers are potential candidates for studies requiring estimations of morning/pre-work blood pressure.

Harnessing the power of neuroplasticity for intervention

A fundamental property of the brain is its capacity to change with a wide variety of experiences, including injury. Although there are spontaneous reparative changes following injury, these changes are rarely sufficient to support significant functional recovery. Research on the basic principles of brain plasticity is leading to new approaches to treating the injured brain. We review factors that affect synaptic organization in the normal brain, evidence of spontaneous neuroplasticity after injury, and the evidence that factors including postinjury experience, pharmacotherapy, and cell-based therapies, can form the basis of rehabilitation strategies after brain injuries early in life and in adulthood.

Microparticles generated during chronic cerebral ischemia deliver proapoptotic signals to cultured endothelial cells

Circulating microparticles (MPs) are involved in many physiological processes and numbers are increased in a variety of cardiovascular disorders. The present aims were to characterize levels of MPs in a rodent model of chronic cerebral hypoperfusion (CCH) and to determine their signaling properties. MPs were isolated from the plasma of rats exposed to CCH and quantified by flow cytometry. When MPs were added to cultured endothelial cells or normal rat kidney cells they induced cell death in a time and dose dependent manner. Analysis of pellets by electron microscopy indicates that cell death signals are carried by particles in the range of 400 nm in diameter or less. Cell death involved the activation of caspase 3 and was not a consequence of oxidative stress. Inhibition of the Fas/FasL signaling pathway also did not improve cell survival. MPs were found to contain caspase 3 and treating the MPs with a caspase 3 inhibitor significantly reduced cell death. A TNF-α receptor blocker and a TRAIL neutralizing antibody also significantly reduced cell death. Levels of circulating MPs are elevated in a rodent model of chronic cerebral ischemia. MPs with a diameter of 400 nm or less activate the TNF-α and TRAIL signaling pathways and may deliver caspase 3 to cultured cells.

Epigenetic code and potential epigenetic-based therapies against chronic diseases in developmental origins

Accumulated findings have demonstrated that the epigenetic code provides a potential link between prenatal stress and changes in gene expression that could be involved in the developmental programming of various chronic diseases in later life. Meanwhile, based on the fact that epigenetic modifications are reversible and can be manipulated, this provides a unique chance to develop multiple novel epigenetic-based therapeutic strategies against many chronic diseases in early developmental periods. This article will give a short review of recent findings of prenatal insult-induced epigenetic changes in developmental origins of several chronic diseases, and will attempt to provide an overview of the current epigenetic-based strategies applied in the early prevention, diagnosis and possible therapies for human chronic diseases.

The increased expression of proteins involved in proliferation, DNA repair and DNA methylation in spleen of mice exposed to E. coli O157:H7 lipopolysaccharide

Previous research showed that the consumption of heat-killed E. coli O157:H7 bacteria resulted in an increase in the level of DNA damage in intestine, liver and spleen cells. We hypothesized that certain bacterial components released from heat-killed bacteria trigger this response. We analysed the possibility that bacterial components [such as lipopolysaccharides (LPS)] could induce changes in the level of proteins involved in cell proliferation, DNA repair and DNA methylation in distal spleen tissues of mice. Four-week-old male mice were provided water supplemented with whole heat-killed E. coli O157:H7 bacteria or components of bacteria (DNA, RNA, proteins and LPS). Spleen cells responded to exposure to whole heat-killed bacteria and LPS with an alteration in the level of PCNA proteins, DNA methylation proteins (DNMT1, DNMT3A, DNMT3B, and MeCP2) and DNA repair proteins (APE1 and KU70). Other bacterial components analysed in this study mostly did not alter protein expression. The data suggest that LPS is a bacterial component capable of inducing molecular changes in naïve spleen cells of hosts exposed to it.