Throughout life, the intestinal epithelium undergoes constant self-renewal from intestinal stem cells. Together with genotoxic stressors and failing DNA repair, this self-renewal causes ...susceptibility toward malignant transformation. X-box binding protein 1 (XBP1) is a stress sensor involved in the unfolded protein response (UPR). We hypothesized that XBP1 acts as a signaling hub to regulate epithelial DNA damage responses.
Data from The Cancer Genome Atlas were analyzed for association of XBP1 with colorectal cancer (CRC) survival and molecular interactions between XBP1 and p53 pathway activity. The role of XBP1 in orchestrating p53-driven DNA damage response was tested in vitro in mouse models of chronic intestinal epithelial cell (IEC) DNA damage (Xbp1/H2bfl/fl, Xbp1ΔIEC, H2bΔIEC, H2b/Xbp1ΔIEC) and via orthotopic tumor organoid transplantation. Transcriptome analysis of intestinal organoids was performed to identify molecular targets of Xbp1-mediated DNA damage response.
In The Cancer Genome Atlas data set of CRC, low XBP1 expression was significantly associated with poor overall survival and reduced p53 pathway activity. In vivo, H2b/Xbp1ΔIEC mice developed spontaneous intestinal carcinomas. Orthotopic tumor organoid transplantation revealed a metastatic potential of H2b/Xbp1ΔIEC-derived tumors. RNA sequencing of intestinal organoids (H2b/Xbp1fl/fl, H2bΔIEC, H2b/Xbp1ΔIEC, and H2b/p53ΔIEC) identified a transcriptional program downstream of p53, in which XBP1 directs DNA-damage-inducible transcript 4-like (Ddit4l) expression. DDIT4L inhibits mechanistic target of rapamycin-mediated phosphorylation of 4E-binding protein 1. Pharmacologic mechanistic target of rapamycin inhibition suppressed epithelial hyperproliferation via 4E-binding protein 1.
Our data suggest a crucial role for XBP1 in coordinating epithelial DNA damage responses and stem cell function via a p53-DDIT4L–dependent feedback mechanism.
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X-box protein 1 coordinates epithelial stem cell function in response to DNA damage in a mechanism involving the tumor suppressor tumor protein p53.
Hexokinases (HK) catalyze the first step of glycolysis limiting its pace. HK2 is highly expressed in gut epithelium, contributes to immune responses, and is upregulated during inflammation. We ...examined the microbial regulation of HK2 and its impact on inflammation using mice lacking HK2 in intestinal epithelial cells (Hk2ΔIEC). Hk2ΔIEC mice were less susceptible to acute colitis. Analyzing the epithelial transcriptome from Hk2ΔIEC mice during colitis and using HK2-deficient intestinal organoids and Caco-2 cells revealed reduced mitochondrial respiration and epithelial cell death in the absence of HK2. The microbiota strongly regulated HK2 expression and activity. The microbially derived short-chain fatty acid (SCFA) butyrate repressed HK2 expression via histone deacetylase 8 (HDAC8) and reduced mitochondrial respiration in wild-type but not in HK2-deficient Caco-2 cells. Butyrate supplementation protected wild-type but not Hk2ΔIEC mice from colitis. Our findings define a mechanism how butyrate promotes intestinal homeostasis and suggest targeted HK2-inhibition as therapeutic avenue for inflammation.
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•Loss of epithelial HK2 protects against acute intestinal inflammation•Ablation of HK2 suppresses cell death and dysregulates mitochondrial function•The microbiome regulates HK2 expression via SCFAs targeting HDAC8•The SCFA butyrate ameliorates intestinal inflammation by downregulating HK2
Hinrichsen and Hamm et al. report that HK2 and its microbial regulation control intestinal homeostasis. Using genetic and gnotobiotic mouse models, they reveal that deleting epithelial HK2 protects against colitis by suppressing cell death and altering mitochondrial function. Further, the microbial metabolite butyrate downregulates HK2, thereby providing protection from colitis.
The high quality demands of batteries for electric vehicles require powerful tools for error detection in cell manufacturing. Furthermore, cell diagnostics is a serious challenge because performance ...limitations occur on atomic scale and as batteries are closed systems physical issues can hardly be detected only with the aid of experimental methods. Physico-chemical models enable to detect up to seven various mechanisms of limitations but experimental parameterization is extensive. Therefore, in this study a fast mathematical parameterization approach was used to simulate and diagnose cells with various manufacturing parameter configurations. Limitation mechanisms are shown in correlation with impacts by calendering, electrode thickness, carbon black recipe and cathode active material. Depending on the adjusted production parameters, they vary between low electronic conductivity, overpotentials due to reduction of electrochemically active solid-liquid interfacial area and low ionic conductivity. Furthermore it is shown that characteristic indicators for the particular limitation mechanisms can be observed in discharge curves at various C-Rates. Finally, a statistical analysis demonstrates how parameter identification can be performed computationally as a side product from reparameterization.
Tissue-resident lymphocytes provide organ-adapted protection against invading pathogens. Whereas their biology has been examined in great detail in various infection models, their generation and ...functionality in response to vaccination have not been comprehensively analyzed in humans. We therefore studied SARS-CoV-2 mRNA vaccine-specific T cells in surgery specimens of kidney, liver, lung, bone marrow, and spleen compared with paired blood samples from largely virus-naive individuals. As opposed to lymphoid tissues, nonlymphoid organs harbored significantly elevated frequencies of spike-specific CD4+ T cells compared with blood showing hallmarks of tissue residency and an expanded memory pool. Organ-derived CD4+ T cells further exhibited increased polyfunctionality over those detected in blood. Single-cell RNA-Seq together with T cell receptor repertoire analysis indicated that the clonotype rather than organ origin is a major determinant of transcriptomic state in vaccine-specific CD4+ T cells. In summary, our data demonstrate that SARS-CoV-2 vaccination entails acquisition of tissue memory and residency features in organs distant from the inoculation site, thereby contributing to our understanding of how local tissue protection might be accomplished.
Closed soft-tissue trauma leads to activation of the coagulation cascade and is often complicated by systemic inflammation and infection. Previous investigations have shown potent anti-inflammatory ...properties of antithrombin. We herein report on the action of antithrombin on skeletal muscle injury in experimental endotoxemia.
By using a pneumatically driven computer-controlled impact device, closed soft-tissue trauma was applied on the left hind limb of pentobarbital-anesthetized rats. Six hours later, endotoxemia was induced by intraperitoneal injection of Escherichia coli lipopolysaccharide. An equivalent volume of physiological saline was given in controls. At the same time point, treatment of animals was started by intravenous injection of antithrombin (250 IU/kg body weight) or vehicle solution. Twenty-four hours after trauma, the extensor digitorum longus muscle was microsurgically exposed and analyzed by means of high-resolution multifluorescence microscopy.
Traumatic soft-tissue injury with additional endotoxemia was characterized by nutritive perfusion failure (functional capillary density: 379±20cm/cm;), tissue hypoxia (nicotinamide adenine dinucleotide autofluorescence: 77±4 aU), and enhanced leukocyte-endothelial cell interaction (773±35 cells/mm;). Therapeutic intervention with antithrombin 6 hrs after trauma restored nutritive perfusion and tissue oxygenation (functional capillary density: 469±22cm/cm; nicotinamide adenine dinucleotide autofluorescence: 61±5 aU p < 0.05) and reduced inflammatory leukocyte adherence (237±20 cells/mm; p < 0.05) toward values found in nontraumatized controls (functional capillary density: 573±13cm/cm; nicotinamide adenine dinucleotide autofluorescence: 56±2 aU; leukocyte adherence: 204±20 cells/mm;).
Antithrombin ameliorates microcirculatory dysfunction and tissue injury in traumatized animals during endotoxemia. Furthermore, a reduced inflammatory cell response helps to prevent leukocyte-dependent secondary tissue injury.
Summary Background The importance of mind-body oriented therapies in oncology has increased in recent years. Eurythmy therapy (EYT, Greek: eurythmy = harmonious rhythm) is a mind-body oriented ...therapy used in Anthroposophic Medicine. EYT can lead to long-term alleviation of chronic disease symptoms and improve patient quality of life. Yet, little is known about underlying physiological mechanisms. Objective This study aims to compare the effects of EYT and conventional ergometer training (CET) on heart rate variability (HRV). Design In a cross-over design, 20 healthy subjects performed two different EYT exercises and two sessions of CET. ECGs were recorded throughout these procedures. HRV was quantified by the extent of very low (VLF), low (LF) and high frequency (HF) oscillations of heart rate. Results VLF and LF oscillations increased during one EYT exercises when compared to rest after EYT (‘B exercise’, VLF: 7.65 vs. 6.57 log ms2 ; LF: 8.06 vs. 6.15 log ms2 ) whereas during the other EYT exercise only LF increased (‘L exercise’, LF: 7.19 vs. 6.25 log ms2 ). HF was not affected. During CET VLF, LF and HF decreased compared to rest (VLF: 5.4 log ms2 , LF: 4.5 log ms2 , HF: 3.2 log ms2 ). During rest after both EYT exercises LF/HF decreased when compared to rest after CET (0.4 and 0.5 vs. 1.4). Conclusion At comparable workloads, EYT stimulated HRV whereas CET attenuated HRV. The decrease of LF/HF during rest after EYT indicates an improved relaxation. These results suggest that patients may benefit from EYT in terms of HRV improvement.
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