Functional alterations and transcriptomic changes during zebrafish cardiac aging

Aging dramatically increases the risk of cardiovascular diseases in human. Animal models are of great value to study cardiac aging, and zebrafish have become a popular model for aging study recently. However, there is limited knowledge about the progression and regulation of cardiac aging in zebrafish. In this study we first validated the effectiveness of a panel of aging-related markers and revealed their spatial-temporal specificity. Using these markers, we discovered that cardiac aging in zebrafish initiated at mid-age around 24 months, followed by a gradual progression marked with increased DNA damage, inflammatory response and reduced mitochondrial function. Furthermore, we showed aging-related expression profile change in zebrafish hearts was similar to that in rat hearts. Overall, our results provide a deeper insight into the cardiac aging process in zebrafish, which will set up foundation for generating novel cardiac aging models suitable for large scale screening of pharmaceutical targets.

Proteomic and transcriptomic changes in rat liver following oral feeding of formaldehyde

Formaldehyde (FA), a ubiquitous volatile organic compound present in a wide range of resources, is a hazardous chemical and human carcinogen. Contamination of FA in food, especially perishable commodities like fish and meat, is a major source of exposure, although it is not recommended for use in food and food products owing to its carcinogenicity. Effects of oral feeding of FA have been studied by evaluating general health, haematology and clinical chemistry in rat. Recent studies have shown that FA exposure leads to detrimental cardiovascular effects. It regulates vascular tensions through nitric oxide-cGMP signalling pathway and ion channels in rats. Although FA is an established carcinogen, molecular studies on carcinogenic potential with dose dependency are meagre. In this context, the present study was undertaken to investigate the toxicogenomic and proteomic alterations in liver of rats fed FA through drinking water. By proteomic analysis, 621 proteins/protein-subunits showed differential abundance (proteome data available via ProteomeXchange with identifier PXD010534), whereas 536 differentially-expressed-genes were identified by transcriptome analysis (data available via Sequence Read Archive with identifier SRR7974113). Gene ontology analysis showed that binding, catalysis, signal transduction were affected in formaldehyde-fed rats. Pathway analysis revealed that formaldehyde-exposure activated PI3K-AKT pathway that leads to inhibition of caspase activity thereby assisting cells to survive against apoptosis. Decreased abundance/down-regulation of ANGPT, eNOS, STAT3 proteins/transcripts and increased abundance of EDN1 indicated decrease in angiogenesis and vasodilatation that restricted hepatic cells from becoming tumorigenic; thus, indicating FA could be less toxic and non-tumorigenic at low concentrations.

Transcriptomic changes in Nicotiana tabacum leaves during mosaic virus infection

To provide a detailed insight into the early biological process of tobacco mosaic disease, transcriptomic changes in tobacco leaves were surveyed at 1, 3 and 5 days after mono-infected by Tobacco mosaic virus (TMV) and co-infected by Cucumber mosaic virus (CMV) and TMV. At the three different stages, there were 2372, 3168 and 2045 differentially expressed genes (DEGs) in mono-infected leaves, and 2388, 3281 and 3417 DEGs were identified in co-infected leaves. There were 836, 1538 and 1185 common DEGs between the mono-infection and co-infection at the three time points, respectively. These common DEGs were enriched in the pathways, such as photosynthesis, biosynthesis of secondary metabolites, plant-pathogen interaction, porphyrin and chlorophyll metabolism, phenylalanine metabolism and phenylpropanoid biosynthesis. Photosynthesis pathway was observably down-regulated, and defense response pathways were markedly up-regulated. These pathways have been found to be related to tobacco mosaic disease. Of these common DEGs, the changes in expression of argonaute proteins, thioredoxins and peroxidases showed that the activation of RNA silencing and the destruction of redox balance can be induced by tobacco mosaic virus infection, resulting in the reset of biology process and damage in tobacco plants. Additionally, the occurrence of symptoms in co-infected tobacco plants was more early and serious than mono-infection, indicating that there is synergy between TMV and CMV in co-infected tobacco plants. The timely usage of antiviral agents and plant resistance inducers can decrease the incidence of tobacco mosaic disease through changing the expression of some DEGs, indicating that these genes can be used to screen novel plant resistance inducers and antiviral agents. Overall, our results were helpful in clarifying the mechanism of tobacco mosaic disease and provided novel strategies for the prevention of tobacco mosaic disease.