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GSE45234
Mus musculus
11 Downloadable Samples
Description
Oxidative stress is a hallmark of inflammation in infection or sterile tissue injury. We show that partially oxidized phospholipids of microvesicles (MVs) from plasma of patients with rheumatoid arthritis or cells exposed to oxidative stress induce activation of TLR4. MVs from healthy donors or reconstituted synthetic MVs can be converted to TLR4 agonists by limited oxidation, while prolonged oxidation abrogates the activity. Activation by MVs mimics the mechanism of TLR4 activation by LPS. However, LPS and MVs induce significantly different transcriptional response profile in mouse BMDMs with a strong inflammation-resolving component induced by the endogenous signals. MVs thus represent a ubiquitous endogenous danger signal released under the oxidative stress, which underlies the pervasive role of TLR4 signaling in inflammation.
Publication Title
Toll-like receptor 4 senses oxidative stress mediated by the oxidation of phospholipids in extracellular vesicles.
Sample Metadata Fields
Sex
View Samples- Mus musculus
- 16 Downloadable Samples
Description
Exosomes are small extracellular nano-vesicles of endocytic origin that mediate different signals between cells, by surface interactions and by shuttling of functional RNA from one cell to another. In this study, we show that exosomes, produced by mouse mast cells exposed to oxidative stress, change their mRNA content and also that these exosomes can influence the response of other cells to oxidative stress by providing recipient cells with a resistance against oxidative stress. Finally, we also show that UV-light affect the biological functions associated with exosomes released under oxidative stress. These results argue that exosomal shuttle of RNA is involved in cell-to-cell communication, by influencing the response of recipient cells to an external stimulus.
Publication Title
Exosomes communicate protective messages during oxidative stress; possible role of exosomal shuttle RNA.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Homo sapiens
- 18 Downloadable Samples
- Affymetrix Clariom S Human array (clariomshuman)
Description
Chronic obstructive pulmonary disease (COPD) is a heterogenous respiratory disease mainly caused by smoking. Respiratory infections constitute a major risk factor for acute worsening of COPD symptoms or COPD exacerbation. Mitochondrial functionality, which is crucial for the execution of physiologic functions of metabolically active cells, is impaired in airway epithelial cells (AECs) of COPD patients as well as smokers. However, the potential contribution of mitochondrial dysfunction in AECs to progression of COPD, infection-triggered exacerbations in AECs and a potential mechanistic link between mitochondrial and epithelial barrier dysfunction is unknown to date. In this study, we used an in vitro COPD exacerbation model based on AECs exposed to cigarette smoke extract (CSE) followed by infection with Streptococcus pneumoniae (Sp). The levels of oxidative stress, as an indicator of mitochondrial stress were quantified upon CSE and Sp. The expression of proteins associated with mitophagy, mitochondrial content and biogenesis as well as mitochondrial fission and fusion was quantified upon CSE and Sp. Transcriptional AEC profiling was performed to identify the potential changes in innate immune pathways and correlate them with mitochondrial function. We found that CSE exposure substantially altered mitochondrial function in AECs by suppressing mitochondrial complex protein levels, reducing mitochondrial membrane potential and increasing mitochondrial stress and mitophagy. Moreover, CSE-induced mitochondrial dysfunction correlated with reduced enrichment of genes involved in apical junctions and innate immune responses to Sp, particularly type I interferon responses. Together, our results demonstrated that CSE-induced mitochondrial dysfunction may contribute to impaired innate immune responses to Sp and may thus trigger COPD exacerbation.
Publication Title
Cigarette Smoke Extract Disturbs Mitochondria-Regulated Airway Epithelial Cell Responses to Pneumococci.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Mus musculus
- 65 Downloadable Samples
Description
It is widely believed that the carcinogenic action of ionizing radiation is due to targeted DNA damage and resulting mutations, but there is also substantial evidence that non-targeted radiation effects alter epithelial phenotype and the stromal microenvironment. Activation of transforming growth factor 1 (TGF) is a non-targeted radiation effect that mediates cell fate decisions following DNA damage and regulates microenvironment composition; it could either suppress or promote cancer. We asked if such non-targeted radiation effects contribute to carcinogenesis by using a novel radiation chimera model. Unirradiated Trp53 null mammary epithelium was transplanted to the mammary stroma, previously divested of endogenous epithelia, of mice previously exposed to a single low (10 -100 cGy) radiation dose. By 300 days, 100% of transplants in irradiated hosts at either 10 or 100 cGy had developed Trp53 null breast carcinomas compared to 54% in unirradiated hosts. Tumor growth rate was also increased by high, but not low, dose host irradiation. In contrast, irradiation of Tgfb1 heterozygote mice prior to transplantation failed to decrease tumor latency, or increase growth rate at any dose. Host irradiation significantly reduced the latency of invasive ductal carcinoma compared to spindle cell carcinoma. However, irradiation of either host genotype significantly increased the frequency of estrogen receptor negative tumors. These data demonstrate two concepts critical to understanding radiation risks. First, non-targeted radiation effects can significantly promote the frequency and alter the features of epithelial cancer. Second, radiation-induced TGF activity is a key mechanism of tumor promotion.
Publication Title
Radiation acts on the microenvironment to affect breast carcinogenesis by distinct mechanisms that decrease cancer latency and affect tumor type.
Sample Metadata Fields
Age, Specimen part
View Samples