Project description:Mouse embryonic stem cells (ESCs) display pluripotency features characteristic of the inner cell mass of the blastocyst. ESC cultures are highly heterogeneous and include a rare population of cells, which recapitulate characteristics of the 2-cell embryo, referred to as 2-cell-like cells (2CLCs). Whether and how ESC and 2CLC respond to environmental cues has not been fully elucidated. Here, we investigate the impact of mechanical stress on the reprogramming of ESC to 2CLC. We show that hyperosmotic stress induces 2CLC and that this induction can occur even after a recovery time from hyperosmotic stress, suggesting a memory response. Hyperosmotic stress in ESCs leads to accumulation of reactive-oxygen species (ROS) as well as ATR checkpoint activation. Importantly, preventing either elevated ROS levels or ATR activation impairs hyperosmotic-mediated 2CLC induction. We further show that ROS generation and the ATR checkpoint act within the same molecular pathway in response to hyperosmotic stress to induce 2CLCs. Altogether, these results shed light on the response of ESC to mechanical stress and on our understanding of 2CLC reprogramming.
Project description:Mouse embryonic stem cells (ESCs) display pluripotency features characteristic of the inner cell mass of the blastocyst. ESC cultures are highly heterogeneous and include a rare population of cells, which recapitulate characteristics of the 2-cell embryo, referred to as 2-cell-like cells (2CLCs). Whether and how ESC and 2CLC respond to environmental cues has not been fully elucidated. Here, we investigate the impact of mechanical stress on the reprogramming of ESC to 2CLC. We show that hyperosmotic stress induces 2CLC and that this induction can occur even after a recovery time from hyperosmotic stress, suggesting a memory response. Hyperosmotic stress in ESCs leads to accumulation of reactive-oxygen species (ROS) as well as ATR checkpoint activation. Importantly, preventing either elevated ROS levels or ATR activation impairs hyperosmotic-mediated 2CLC induction. We further show that ROS generation and the ATR checkpoint act within the same molecular pathway in response to hyperosmotic stress to induce 2CLCs. Altogether, these results shed light on the response of ESC to mechanical stress and on our understanding of 2CLC reprogramming.
Project description:We examined the possible effect of hyperosmotic stress on Arabidopsis transcriptome using mRNA-seq. We found that the transcriptome is reprogrammed in response to hyperosmotic stress, in a DCP5-dependent.
Project description:How chondrocytes of the synovial joint sense and respond to hyperosmotic stress to maintain joint homeostasis over time is undetermined. The With-No-Lysine (K) (WNK) protein kinases are major intracellular sensors of hyperosmotic stress that respond by regulating ion channel activity and signaling pathways. To determine if WNK2 is a hyperosmotic sensor in chondrocytes and to identify the genes and pathways regulated by WNK2, we examined the molecular response of chondrocytes to WNK2 overexpression and hyperosmotic stress.
Project description:Oral streptococci metabolize carbohydrate to produce organic acids, which not only decrease the environmental pH, but also increase osmolality of dental plaque fluid due to tooth demineralization and consequent calcium and phosphate accumulation. Despite these unfavorable environmental changes, the bacteria continue to thrive. The aim of this study was to obtain a global view on strategies taken by Streptococcus mutans to deal with physiologically relevant elevated osmolality, and perseveres within a cariogenic dental plaque. We investigated phenotypic change of S. mutans biofilm upon hyperosmotic challenge. We found that the hyperosmotic condition was able to initiate S. mutans biofilm dispersal by reducing both microbial content and extracellular polysaccharides matrix. We then used whole-genome microarray with quantitative RT-PCR validation to systemically investigate the underlying molecular machineries of this bacterium in response to the hyperosmotic stimuli. Among those identified 40 deferentially regulated genes, down-regulation of gtfB and comC were believed to be responsible for the observed biofilm dispersal. Further analysis of microarray data showed significant up-regulation of genes and pathways involved in carbohydrate metabolism. Specific genes involved in heat shock response and acid tolerance were also upregulated, indicating potential cross-talk between hyperosmotic and other environmental stress. Hyperosmotic condition induces significant stress response on S. mutans at both phenotypic and transcriptomic levels. In the meantime, it may take full advantage of these environmental stimuli to better fit the fluctuating environments within oral cavity, and thus emerges as numeric-predominant bacterium under cariogenic conditions.
Project description:Oral streptococci metabolize carbohydrate to produce organic acids, not only decrease the environmental pH, but also increase osmolality of dental plaque fluid due to tooth demineralization and consequent calcium and phosphate accumulation. Thus, to persevere in the dental plaque, acidogenic bacteria should evolve sophisticated molecular machineries to counter the detrimental effect of elevated osmolality. This study was aimed to obtain a global view on strategies taken by streptococcus mutans to deal with physiologically relevant elevated osmolality, and preserves within a cariogenic dental plaque. We investigated phenotypic change of S. mutans biofilm upon sub-lethal level of hyperosmotic challenge. We found that hyperosmotic condition was able to initiate S. mutans biofilm dispersal by reducing both microbial content and extracellular polysaccharides matrix. We then used DNA microarray with qPCR validation to systemically investigate the underlying molecular machinery of this bacteria in response to hyperosmotic stimuli. Among those identified 50 differentially regulated genes, down-regulation of gtfB and comC were believed to be responsible for the observed biofilm dispersal. Further analysis of microarray data showed significant up-regulation of genes and pathways involved in carbohydrates metabolism. Specific genes involved in heat shock response and acid tolerance were also upregulated, indicating potential cross-talk between hyperosmotic and other environmental stress. Based on the data obtained in this study, we believe that although hyperosmotic condition may induce significant stress response on S. mutans, this cariogenic bacterium has evolved sophisticated molecular machineries to counter those elicited detrimental effects. In the meantime, it will take full advantage of these environmental stimuli to better fit the fluctuating environments within oral cavity, and thus emerge as numeric-predominant bacteria under cariogenic conditions. A six-chip study using total RNA recovered from mid-logarithmic phase of S. mutans UA159 from three separate cultures of strains submitted for 15 minutes to hyperosmotic stimuli (0.4M NaCl) and three separate cultures of strains kept under no stress condition.
Project description:Drought and salinity are most ubiquitous environmental factors that causing hyperosmotic threats to Sphingomonas and impairs their efficiency of performing environmental functions. However, bacteria have developed various responses and regulation systems to coping with these abiotic challenges. Among which post-transcriptional regulation plays vital roles in regulating gene expression and cellular homeostasis, as hyperosmotic stress conditions could lead to induction of specific small RNA (sRNA) that participates in stress response regulation. Here, we report a candidate functional sRNAs landscape of S. melonis which could help for comprehensive analyses of sRNA regulation in Sphingomonas species. WGCNA analysis revealed a 263 nt sRNA SNC251 which transcribed from its own promoter and shew the most dramatic correlation coefficient with hyperosmotic factors was characterized. An in vivo translation-reporter system constructed in this study revealed positive regulation and feedback mechanisms between the SNC251 and nicotine degradation genes. Deletion of snc251 affected multiple cellular processes and nicotine degradation capacity of S. melonis TY, while overexpression of SNC251 facilitated the biofilm formation capability of TY under hyperosmotic stress. Two genes of TonB system were further verified could be activated by SNC251, which also means SNC251 is a trans-acting small RNA. Briefly, this research reported a summary of sRNAs which participate in hyperosmotic stress response in S. melonis TY and revealed a novel sRNA SNC251 which is necessary for hyperosmotic stress response.
Project description:ChIP-seq was performed using antibodies against Integrator subunits 11 or 3 to measure the occupancy of these proteins on DNA after hyperosmotic stress.
Project description:For the detection of tiRNAs accumulated in Cyt c-IP vs tiRNAs in total cell lysates during hyperosmotic stress in the presence of angiogenin Total cell lysates from mouse embryonic fibroblasts treated with angiogenin under hyperosmotic stress. Lysates split into two parts: one part serveed as the total RNA, the other part served as Cyt c-IP fraction. Small RNAs were enriched from both parts and went through deep sequencing followed by bioinformatic analysis.
Project description:Stress-induced readthrough transcription results in the synthesis of thousands of downstream-of-gene (DoG) containing transcripts. The mechanisms underlying DoG formation during cellular stress remain unknown. Nascent transcription profiles during DoG induction in human cell lines using TT-TimeLapse-seq revealed that hyperosmotic stress induces widespread transcriptional repression. Yet, DoGs are produced regardless of the transcriptional level of their upstream genes. ChIP-seq confirmed that the stress-induced redistribution of RNA Polymerase (Pol) II correlates with the transcriptional output of genes. Stress-induced alterations in the Pol II interactome are observed by mass spectrometry. While subunits of the cleavage and polyadenylation machinery remained Pol II-associated, Integrator complex subunits dissociated from Pol II under stress conditions. Depleting the catalytic subunit of the Integrator complex, Int11, using siRNAs induces hundreds of readthrough transcripts, whose parental genes partially overlap those of stress-induced DoGs. Our results provide insights into the mechanisms underlying DoG production and how Integrator activity influences DoG transcription. This SuperSeries is composed of the SubSeries listed below.