Project description:Long-term exposure to particulate air pollutants has been linked to increased incidence of Type 2 Diabetes (T2DM). Recently, we showed that the gaseous pollutant, O3, induced glucose intolerance, and increased serum leptin and epinephrine in Brown Norway rats. In this study, we hypothesized that O3 exposure will cause broad scale changes in metabolic homeostasis involving liver, muscle and adipose tissues, and that serum metabolomic and liver transcriptomic profiling will provide mechanistic insights into pollutant-induced metabolic alterations. In the first experiment, male Wistar Kyoto (WKY) rats were exposed to filtered air (FA) or O3 at 0.25, 0.50, or 1.00 ppm, 6h/day for two consecutive days to establish concentration-related effects on glucose tolerance and lung injury. In a second experiment, rats were exposed to FA or 1.0 ppm O3, 6h/day for either one day or two consecutive days and systemic metabolic responses were determined immediately after each exposure or after an 18h recovery period. In WKY rats, O3 increased serum fasting glucose and leptin on day 1. Glucose intolerance persisted through two days of exposure but reversed 18h post second exposure. O3 exposure increased circulating metabolites of glycolysis, long-chain free fatty acids, branched chain amino acids (BCAA) and cholesterol while 1,5- anhydroglucitol, bile acids and metabolites of TCA cycle were decreased, indicating impaired glycemic control, muscle proteolysis and adipose lipolysis. Liver gene expression profile after O3 exposure reflected a response to the serum metabolite changes, as evidenced by increased expression of genes for glycolysis, TCA cycle and gluconeogenesis, and decreased expression of genes involved in steroid and fat biosynthesis. In conclusion, short-term O3 exposure induced hormonal changes and global metabolic disorder reflective of changes in peripheral glucose, lipid, and amino acid metabolism, representative of a stress-response. It remains to be examined if these metabolic alterations contribute to insulin resistance upon chronic exposure.

Project description:Long-term exposure to particulate air pollutants has been linked to increased incidence of Type 2 Diabetes (T2DM). Recently, we showed that the gaseous pollutant, O3, induced glucose intolerance, and increased serum leptin and epinephrine in Brown Norway rats. In this study, we hypothesized that O3 exposure will cause broad scale changes in metabolic homeostasis involving liver, muscle and adipose tissues, and that serum metabolomic and liver transcriptomic profiling will provide mechanistic insights into pollutant-induced metabolic alterations. In the first experiment, male Wistar Kyoto (WKY) rats were exposed to filtered air (FA) or O3 at 0.25, 0.50, or 1.00 ppm, 6h/day for two consecutive days to establish concentration-related effects on glucose tolerance and lung injury. In a second experiment, rats were exposed to FA or 1.0 ppm O3, 6h/day for either one day or two consecutive days and systemic metabolic responses were determined immediately after each exposure or after an 18h recovery period. In WKY rats, O3 increased serum fasting glucose and leptin on day 1. Glucose intolerance persisted through two days of exposure but reversed 18h post second exposure. O3 exposure increased circulating metabolites of glycolysis, long-chain free fatty acids, branched chain amino acids (BCAA) and cholesterol while 1,5- anhydroglucitol, bile acids and metabolites of TCA cycle were decreased, indicating impaired glycemic control, muscle proteolysis and adipose lipolysis. Liver gene expression profile after O3 exposure reflected a response to the serum metabolite changes, as evidenced by increased expression of genes for glycolysis, TCA cycle and gluconeogenesis, and decreased expression of genes involved in steroid and fat biosynthesis. In conclusion, short-term O3 exposure induced hormonal changes and global metabolic disorder reflective of changes in peripheral glucose, lipid, and amino acid metabolism, representative of a stress-response. It remains to be examined if these metabolic alterations contribute to insulin resistance upon chronic exposure. Rats were exposed to filtered air (FA) or Ozone at 1 ppm, 6h/day for two consecutive days to establish ozone-exposure related effects on transcriptomic profiles. Samples were taken at three time points: 1 day (1day0hrs) - at the end of the 6 hour exposure period, 2 days (2day0hrs) - at the end of the of the second day 6 hour exposure period) and 2 days 18 hours (2day18hrs) - 18 hours after the 6 hour exposure period on the second day. Total liver RNA was isolated from ~20 mg tissue with a commercially available RNeasy mini kit (Qiagen, Valencia, CA) using silica gel membrane purification. Liver RNA was resuspended in 30μl of RNAse- free water. RNAse inhibitor was added and RNA yield was determined spectrophotometrically on a NanoDrop 1000 (Thermo Scientific, Wilmington, DE). RNA integrity was assessed by the RNA 6000 LabChip® kit using a 2100 Bioanalyzer (Agilent Technologies, Palo Alto, CA). We examined global gene expression changes using the Affymetrix platform (RG- 230 PM Array strip). Biotin-labeled cRNA was produced from total RNA using an Affymetrix “IVT-express labeling kit “(cat# 901229).

Project description:Plant productivity is adversely affected by exposure to abiotic stresses including salinity. Leaf tissue undergoes accelerated senescence with exposure to salt stress conditions, culminating in lowered efficiency of photosynthetic machinery. The N6-adenine derivative phytohormone Cytokinin (CK) is well known to delay natural leaf senescence by maintaining functioning photosynthesis processes. How various forms of CK function to control this activity and alter physiological and molecular responses under salt-induced leaf senescence is still not known. Here the CKs, trans-Zeatin (tZ) and its N-glucosylated (tZNGs) forms; tZ7G and tZ9G, were tested for their ability to delay leaf senescence in Arabidopsis thaliana. A modified dark-induced leaf senescence CK bioassay was used to study the physiology of photosynthesis performance as well as transcriptome and proteome level changes in detached leaves, across different phases of salt-induced leaf senescence from 2h-72h. Treatments with different CK forms (tZ, tZ7G, and tZ9G) showed that tZNGs can improve PSII efficiency (Fv/Fm) and increase chlorophyll levels compared to salt only treatments, indicating that these CK forms function as active CK forms in delaying senescence. At the transcript level, tZ, tZ7G, and tZ9G revealed differentially expressed genes (DEGs) across both developmental and salt-treated senescence, with tZNGs predominantly altering DEG in the terminal timepoint of salt-treated leaf senescence. Additionally, we found that tZNGs uniquely regulate crucial biological processes (BPs) including CK signaling compared to tZ. Proteome analysis showed that tZNGs and tZ showed similarities in number of differentially abundant proteins (DAPs) trends across senescence timepoints although each of the three forms showing uniquely abundant proteins. GO term analysis for tZNG regulated genes and proteins revel the enrichment of senescence- and chloroplast-related BPs. This study highlights the role of tZNGs as active cytokinin forms towards delaying salt-treated leaf senescence in Arabidopsis at the physiology, transcriptome, and proteome level.

Dataset Information

Genes responding to O3 are regulated during leaf development in hybrid poplar (Populus tremula x alba)

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets