An integrated systems approach for understanding cellular responses to gamma radiation.
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ABSTRACT: Cellular response to stress entails complex mRNA and protein abundance changes which translate into physiological adjustments for maintaining homeostasis as well as to repair and minimize damage to cellular components. We have characterized the response of the halophilic archaeon Halobacterium salinarum NRC-1 to 60Co ionizing gamma radiation in an effort to understand correlation between genetic information processing and physiological changes. The physiological response model we have constructed is based on integrated analysis of temporal changes in global mRNA and protein abundance along with protein-DNA interactions and evolutionarily conserved functional associations. This systems view reveals cooperation amongst several cellular processes including DNA repair, increased protein turnover, apparent shifts in metabolism to favor nucleotide biosynthesis and an overall effort to repair oxidative damage. Further, we demonstrate the importance of time dimension while correlating mRNA and protein levels and suggest that steady state comparisons may be misleading while assessing dynamics of genetic information processing across transcription and translation. Keywords: Time course after gamma irradiation
Project description:The edible cyanobacterium Arthrospira is highly resistant to ionising radiation. How theses cells can escape, protect or repair the radiation damage is not known, and requires additional molecular investigation. Therefore, in this study, Arthrospira cells were shortly exposed to different doses of 60Co gamma rays and the dynamic response of Arthrospira cells to irradiation was investigated by monitoring its gene expression and cell physiology, after irradiation. The dynamic transcriptome and associated physiological traits showed clearly two events: (1) an intense global emergency response with general reprogramming of carbon and energy metabolism and (2) a recovery period. Genes expressed during early response indicated a reduction of photosynthesis and reduced tricarboxilic acid (TCA) and Calvin Benson Cycles, while a likely activation of pentose phosphate pathway. Activation of biosynthesis of additional carbon storage molecules, compatible solutes, vitamins and sugars transport occurred after irradiation. In addition the cells enhance the restoration of the redox homeostasis. The repair mechanism of Arthrospira cells involve mainly proteases for cellular cleaning and removal of damaged proteins, single strand DNA repair and restriction modification system. During recovery, Arthrospira relies on the powerful antioxidant Glutathione molecule, for ROS detoxification. The exposed cells expressed during recovery period also again highly the arh genes, coding for a group of novel proteins which were detected in our previous irradiation studies, which confirms our hypothesis that they are a key element in the radiation resistance and merit further detailed investigation. This study provides new insights into phasic response and the cellular pathways involved the radiation resistance of microbial cells, in particularly for photosynthetic organisms as the cyanobacterium Arthrospira.
Project description:To investigate whether circRNAs have the potential for being radiation biomarker,we screened the radiation-induced differential expressed circRNAs in the AHH-1 cell line exposed to 60Co γ rays. And we established 4 expression models for radiation dose estimation by use of the validated radiation-induced differential expressed circRNAs.
Project description:By characterizing physiological changes that occur in warfighters during simulated combat, we can start to unravel the key biomolecular components that are linked to physical and cognitive performance. Viable field-based sensors for the warfighter must be rapid and noninvasive. In an effort to facilitate this, we applied a multiomics pipeline to characterize the stress response in the saliva of warfighters to correlate biomolecular changes with overall performance and health. In this study, two different stress models were observed - one of chronic stress and one of acute stress. In both models, significant perturbations in the immune, metabolic, and protein manufacturing/processing systems were observed. However, when differentiating between stress models, specific metabolites associated with the 'fight or flight' response and protein folding were seen to be discriminate of the acute stress model.
Project description:A 5′, 7-methylguanosine cap is a quintessential feature of RNA polymerase II-transcribed RNAs, and thus a textbook aspect of co-transcriptional pre-mRNA processing. The cap is bound by the cap-binding complex (CBC), canonically consisting of nuclear cap-binding proteins 1 and 2 (NCBP1/2). Recently, NCBP3 has been proposed to form an alternative, non-canonical CBC, together with NCBP1. NCBP3 has also been shown to interact with the canonical CBC along with the protein SRRT (aka ARS2), in a manner that is mutually exclusive with the RNA export factor, PHAX. Taken together, ambiguities and missing information in the bona fide physiological protein-protein associations of NCBP3 persist. In an effort to clarify the compositions of NCBP1-, 2-, and 3-related macromolecular assemblies, including their intersections and differences, we have applied our recently developed interactome screening platform (PMID: 25938370). Here the experimental design and data processing have been modified and updated to identify interactome differences between targets of affinity capture under a wide range of experimental conditions, followed by label-free quantitative mass spectrometry.
Project description:The endothelium is the barrier separating blood and tissue. Radiation-induced enhanced inflammation leading to permeability of this barrier may increase the risk of cardiovascular disease. The aim of this study was to investigate the onset of endothelial inflammatory pathways after radiation exposure. Human coronary artery endothelial cells (HCECest2) were exposed to radiation doses of 0, 0.25, 0.5, 2.0 and 10 Gy (60Co-γ). The cells were harvested 4 h, 24 h, 48 h and 1 wk post-irradiation. The proteomics analysis was performed in a label-free data-independent acquisition mode. The data were validated using bioinformatics and immunoblotting. The low- and moderate-dose-treated samples showed only small proteome changes. In contrast, an activation of DNA-damage repair, inflammation, and oxidative stress pathways was seen after high-dose treatments (2 and 10 Gy). The level of the DNA damage response protein DDB2 was enhanced early at the 10 Gy dose. The expression of proteins belonging to the inflammatory response or cGAS-STING pathway (STING, STAT1, ICAM1, ISG15) increased in a dose-dependent manner showing the strongest effects at 10 Gy after one week. This study suggests a connection between radiation-induced DNA damage and induction of inflammation and supports inhibition of cGAS-STING pathway in the prevention of radiation-induced cardiovascular disease.
Project description:To gain a comprehensive systems-level understanding of cellular phenotypes, it is critical to characterize the relationship between the dynamic transcriptome and proteome during environmental perturbations. Previous comparisons have shown a lack of correlation between mRNA and protein level measurements suggesting a predominant role for post-transcriptional regulation in mediating cellular environmental responses. To investigate the extent of post-transcriptional regulation, we have analyzed transcriptome and proteome level changes over a 13-hour 28-point time course during transitions between oxic and anoxic physiologies of Halobacterium. Integrated computational analyses of these data show that temporally shifting mRNA and protein profiles relative to one another significantly increases the mRNA/protein correlation. Although time lags for unrelated genes vary widely, we observe similar temporal lags between the transcription and translation of functionally related genes. In contrast, no significant temporal separation was observed within the transcript profiles. Taken together, these data suggest that while there is indeed a direct correlation between many corresponding changes at mRNA and protein levels, translational delay may be the predominant mechanism for the temporal regulation of protein abundance during physiological oxic/anoxic transitions in Halobacterium. The approach and algorithms delineated in this study provide a framework for incorporating the temporal dimension of information processing across many different layers of gene regulation. Keywords: time course