Integrated transcriptome and methylome analyses reveal the molecular regulation of drought stress in wild strawberry (Fragaria nilgerrensis).

BACKGROUND: Fragaria nilgerrensis, which is a diploid wild strawberry with excellent drought-resistance, would provide useful candidate genes for improving drought resistance of cultivated strawberry. So far, its molecular regulatory networks involved in drought stress are unclear. We therefore investigated the drought response regulatory networks of F. nilgerrensis based on the integrated analysis of DNA methylation, transcriptome and physiological traits during four time points under drought stress.  RESULTS: The most differentially expressed genes and the physiological changes were found at 8 days (T8) compared with 0 day (T0, control). Methylome analysis revealed slight dynamic changes in genome-wide mC levels under drought conditions, while the most hypomethylated and hypermethylated regions were identified at T4 and T8. Association analysis of the methylome and transcriptome revealed that unexpressed genes exhibited expected hypermethylation levels in mCHG and mCHH contexts, and highly expressed genes exhibited corresponding hypomethylation levels in the gene body, but mCG contexts showed the opposite trend. Then, 835 differentially methylated and expressed genes were identified and grouped into four clustering patterns to characterize their functions. The genes with either negative or positive correlation between methylation and gene expression were mainly associated with kinases, Reactive Oxygen Species (ROS) synthesis, scavenging, and the abscisic acid (ABA) signal pathway. Consistently, weighted gene co-expression network analysis (WGCNA) revealed Hub genes including NCED, CYP707A2, PP2Cs and others that play important roles in the ABA signaling pathway. CONCLUSION: F. nilgerrensis drought is dominated by ABA-dependent pathways, possibly accompanied by ABA-independent crosstalk. DNA methylation may affect gene expression, but their correlation was more subtle and multiple types of association exist. Maintaining the balance between ROS regeneration and scavenging is an important factor in drought resistance in F. nilgerrensis. These results deepen our understanding of drought resistance and its application in breeding in strawberry plants.

Effects of leptin on norepinephrine in acute ischemic stroke.

Stroke is a multifactorial disease and a consequence of morbidities of diabetes, obesity, hypertension, and heart diseases. Leptin is a major adipokine that regulates weight balance and energy homeostasis, the level of which has been considered as an indicator of acute ischemic stroke. In the present study, we confirmed the high level of leptin and noradrenaline in stroke patients and mouse models as well as oxygen-glucose deprivation (OGD) primary cerebral neurons. Leptin administration increased noradrenaline concentration and dopamine ß-monooxygenase (DBH) but decreased noradrenaline transporter (NET) expression in primary cerebral neurons. Moreover, induced noradrenaline concentration, DBH activity, and inhibited NET were blunted by TG101348 (JAK2 inhibitor). JAK2 silencing also abolished the effects of leptin on noradrenaline metabolism.

Dynamic Changes of DNA Methylation During Wild Strawberry (Fragaria nilgerrensis) Tissue Culture.

Tissue culture is an important tool for asexual propagation and genetic transformation of strawberry plants. In plant tissue culture, variation of DNA methylation is a potential source of phenotypic variation in regenerated plants. However, the genome wide dynamic methylation patterns of strawberry tissue culture remain unclear. In this study, we used whole-genome bisulfite sequencing (WGBS) to study genomic DNA methylation changes of a wild strawberry Fragaria nilgerrensis at six stages: from explants of shoot tips to outplanting and acclimation. Global methylation levels showed that CG sites exhibited the highest methylation level in all stages with an average of 49.5%, followed by CHG (33.2%) and CHH (12.4%). Although CHH accounted for the lowest proportion of total cytosine methylation, it showed the most obvious methylation change and the most of these changes occurred in the transposable element regions. The overall methylation levels alternately decreased and increased during the entire tissue culture process and the distribution of DNA methylation was non-uniform among different genetic regions. Furthermore, much more differentially methylated regions (DMRs) were detected in dedifferentiation and redifferentiation stages and most of them were transposable elements, suggesting these processes involved activating or silencing of amounts of transposons. The functional enrichment of the DMR-related genes indicated that genes involved in hormone metabolic processes, plant development and the stress response changed methylation throughout the tissue culture process. Finally, the quantitative real-time PCR (qRT-PCR) was conducted to examine the association of methylation and gene expression of a set of different methylated genes. Our findings give deeper insight into the epigenetic regulation of gene expression during the plant tissue cultures process, which will be useful in the efficient control of somaclonal variations and in crop improvement.

Autologous transplantation of endothelial progenitor cells to prevent multiple organ dysfunction syndromes in pig.

BACKGROUND: It was observed that the number and function of endothelial progenitor cells (EPCs) decreased sharply in the progression of multiple organ dysfunction syndrome (MODS), and it may be the main pathogenesis for MODS. We aim to perform autologous transplantation of EPCs on animal models of MODS to investigate whether EPCs might be used to prevent MODS caused by severe sepsis. METHODS: A total of 60 pigs were randomly divided into three groups: subjected to hemorrhagic shock + resuscitation + endotoxemia only (MODS group); performed autologous transplantation of EPCs after hemorrhagic shock + resuscitation + endotoxemia (transplantation group); and control group. Mononuclear cells of animals of the transplantation group were isolated by density-gradient centrifugation for ex vivo expansion, and the six-passage EPCs labeled with 5-carboxyfluorescein diacetate succinimidyl ester were autologously transplanted at a density of 1 × 10(7) cells/kg body weight at the 24th hour after endotoxemia. The function of important organs was monitored continuously to assess the effects of autologous transplantation of EPCs on MODS. RESULTS: All animals of the MODS group developed MODS (100%), and 17 (85%) of 20 animals died because of MODS; the incidence of MODS and mortality rate in the transplantation group were 45% (9 of 20 pigs; p < 0.01) and 35% (7 of 20 pigs; p < 0.01). In transplantation group, the incidence of pulmonary dysfunction, cardiac dysfunction, hepatosis, and renal dysfunction were 40%, 10%, 5%, and 15%, respectively. The capillary densities of important organs, including the heart, liver, kidney, intestine, and lung, after autologous transplantation of EPCs were significantly higher than those in the MODS group (p < 0.01). CONCLUSION: Autologous transplantation of EPCs could migrate to injured organs and induce angiogenesis to restore blood flow that could improve the function of important organs. It could prevent the incidence of MODS and reduce mortality rate caused by trauma and severe sepsis. Autologous transplantation of EPCs would be a novel, cell-based, vascular endothelium-targeted therapeutic strategy for MODS.