Search

Background/objectives: The porcine intestinal epithelium plays a fundamental role as a defence interface against pathogens. Its alteration can cause severe inflammatory conditions and diseases. Hyperosmotic stress under physiological conditions and upon pathogen challenge can cause malabsorption. Different cell types counteract the osmolarity increase by accumulating organic osmolytes such as betaine, taurine, and myo-inositol through specific transporters. Betaine is known for protecting cells from hyperosmotic stress and has positive effects when fed to pigs. The aim of this study is to demonstrate the modulation of osmolyte transporters gene expression in IPEC-J2 during osmolarity changes and assess the effects of betaine. Methods: IPEC-J2 were seeded in transwells, where differentiate as a polarized monolayer. Epithelial cell integrity (TEER), oxidative stress (NO) and gene expression of osmolyte transporters, tight junction proteins (TJp) and pro-inflammatory cytokines were evaluated. Results: Cells treated with NaCl hyperosmolar medium (500 mOsm/L) showed a TEER decrease at 3 h and detachment within 24 h, associated with an osmolyte transporters reduction. IPEC-J2 treated with mannitol hyperosmolar medium (500 mOsm/L) upregulated taurine (TauT), myo-inositol (SMIT) and betaine (BGT1) transporters expression. A decrease in TJp expression was associated with a TEER decrease and an increase in TNFα, IL6, and IL8. Betaine could attenuate the hyperosmolarity-induced reduction in TEER and TJp expression, the NO increase and cytokines upregulation. Conclusions: This study demonstrates the expression of osmolyte transporters in IPEC-J2, which was upregulated upon hyperosmotic treatment. Betaine counteracts changes in intracellular osmolarity by contributing to maintaining the epithelial barrier function and reducing the inflammatory condition. Compatible osmolytes may provide beneficial effects in therapies for diseases characterized by inflammation and TJp-related dysfunctions. [ABSTRACT FROM AUTHOR]

Upon glucose starvation, S. cerevisiae shows a dramatic alteration in transcription, resulting in wide-scale repression of most genes and activation of some others. This coincides with an arrest of cellular proliferation. A subset of such cells enters quiescence, a reversible non-dividing state. Here, we demonstrate that the conserved transcriptional corepressor Tup1 is critical for transcriptional repression after glucose depletion. We show that Tup1-Ssn6 binds new targets upon glucose depletion, where it remains as the cells enter the G0 phase of the cell cycle. In addition, we show that Tup1 represses a variety of glucose metabolism and transport genes. We explored how Tup1 mediated repression is accomplished and demonstrated that Tup1 coordinates with the Rpd3L complex to deacetylate H3K23. We found that Tup1 coordinates with Isw2 to affect nucleosome positions at glucose transporter HXT family genes during G0. Finally, microscopy revealed that a quarter of cells with a Tup1 deletion contain multiple DAPI puncta. Taken together, these findings demonstrate the role of Tup1 in transcriptional reprogramming in response to environmental cues leading to the quiescent state. Author summary: Quiescence is a very common and important state for the cells of many organisms, where cell functions 'pause' but can resume when the right conditions are met. Most microbes exist in a quiescent state and will start growing and dividing again in the presence of nutrients or other cues. In mammals, a quiescent state is used to maintain stem cell populations and cancer cells often evade treatment by entering quiescence. The budding yeast Saccharomyces cerevisiae is an excellent model for studying quiescence because we can easily isolate populations of quiescent cells. Since budding yeast share many proteins and cellular pathways with higher organisms, our findings are applicable to more complex systems, which may be relevant to maintenance of healthy cells or provide insight to treating disease states. We know that a hallmark of quiescence is reduced transcription, and we are interested in how this change occurs. We have examined how the protein Tup1 causes changes in gene expression in cellular quiescence. We also looked at how Tup1-dependent changes depend on other chromatin interacting factors, such as the histone deacetylase Rpd3, the transcription factor Xbp1, or the chromatin remodeling protein Isw2. [ABSTRACT FROM AUTHOR]

Bovine mastitis is among the most serious disease in the dairy industry and brings huge economic losses due to the decrease in milk quality and quantity. Betaine, a naturally occurring compound, possesses several pharmacological activities including anti-inflammatory and anti-oxidant ability, but whether betaine has protective effects on bovine mastitis is unknown. The aim of this study is to investigate the effect of betaine on mastitis and further discover its feasible molecular mechanism in lipopolysaccharide (LPS)-stimulated bovine mammary epithelial cells (BMECs). BMECs were pre-treated with or without betaine or LPS. Cell viability was measured with CCK-8 to examine the cytotoxicity. The levels of pro-inflammatory cytokines were measured by ELISA kits. Western blotting was used to explore the regulation of genes associated with inflammatory and oxidative stress genes. The results showed that LPS treatment significantly increased the production of pro-inflammation (IL-1β, IL-6 and TNFα), enhanced malondialdehyde (MDA) content, reduced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, and markedly up-regulated the protein expression of COX2 and iNOS (p < 0.05). However, betaine pre-treatment remarkably restored the above phenomenon compared with the LPS group. Additionally, we also observed that betaine exposure significantly restricted LPS-induced the phosphorylation of IκB and NF-κB p65 (p < 0.05). Moreover, pre-treatment of BMECs with betaine abolished LPS-induced the increase of Nrf2 and HO-1 protein levels (p < 0.05). These results confirm that betaine can alleviate LPS-induced inflammatory response and oxidative damage by modulating NF-κB and Nrf2 signalling pathways. Betaine alleviated the production of pro-inflammation cytokines (IL-1β, IL-6 and TNFα) in BMECs after LPS stimulation. Betaine restored LPS-elicited nuclear factor kappa-B (NF-κB) signalling pathway activity. Betaine recovered LPS-induced the activity of SOD and GSH-Px and MDA content. Betaine inhibited the increase of protein expression of Nrf2 and HO-1 challenged with LPS. [ABSTRACT FROM AUTHOR]

The identification of traces of life beyond Earth (e.g., Mars, icy moons) is a challenging task because terrestrial chemical-based molecules may be destroyed by the harsh conditions experienced on extraterrestrial planetary surfaces. For this reason, studying the effects on biomolecules of extremophilic microorganisms through astrobiological ground-based space simulation experiments is significant to support the interpretation of the data that will be gained and collected during the ongoing and future space exploration missions. Here, the stability of the biomolecules of the cryptoendolithic black fungus Cryomyces antarcticus , grown on two Martian regolith analogues and on Antarctic sandstone, were analysed through a metabolomic approach, after its exposure to Science Verification Tests (SVTs) performed in the frame of the European Space Agency (ESA) Biology and Mars Experiment (BIOMEX) project. These tests are building a set of ground-based experiments performed before the space exposure aboard the International Space Station (ISS). The analysis aimed to investigate the effects of different mineral mixtures on fungal colonies and the stability of the biomolecules synthetised by the fungus under simulated Martian and space conditions. The identification of a specific group of molecules showing good stability after the treatments allow the creation of a molecular database that should support the analysis of future data sets that will be collected in the ongoing and next space exploration missions. [ABSTRACT FROM AUTHOR]

Recent evidence indicates that the plasticity of preexisting hepatocytes and bile duct cells is responsible for the appearance of intermediate progenitor cells capable of restoring liver mass after injury without the need of a stem cell compartment. However, mesenchymal stem cells (MSCs) exist in all organs and are associated with blood vessels which represent their perivascular stem cell niche. MSCs are multipotent and can differentiate into several cell types and are known to support regenerative processes by the release of immunomodulatory and trophic factors. In the liver, the space of Disse constitutes a stem cell niche that harbors stellate cells as liver resident MSCs. This perivascular niche is created by extracellular matrix proteins, sinusoidal endothelial cells, liver parenchymal cells and sympathetic nerve endings and establishes a microenvironment that is suitable to maintain stellate cells and to control their fate. The stem cell niche integrity is important for the behavior of stellate cells in the normal, regenerative, aged and diseased liver. The niche character of the space of Disse may further explain why the liver can become an organ of extra-medullar hematopoiesis and why this organ is frequently prone to tumor metastasis. [ABSTRACT FROM AUTHOR]

Objective: To investigate the utility of 13N-ammonia PET/CT imaging in the differential diagnosis of gliomas and brain inflammations.Methods: 13N-ammonia PET/CT imaging data of 77 patients with gliomas and 34 patients with brain inflammations were retrospectively analyzed. No patients received any treatment before 13N-ammonia imaging. All the patients were diagnosed by stereotactic biopsy or clinical follow-up. Visual and semi-quantitative analysis was performed to analyze the results of 13N-ammonia imaging. Finally, the uptake ratios of each lesion were calculated and its differences among different groups were tested with one-way ANOVA.Results: 29.4% inflammations, 51.6% low-grade gliomas and 91.3% high-grade gliomas were positive by visual analysis in 13N-ammonia imaging. The sensitivity, specificity and accuracy for the diagnosis of gliomas were 75.3%, 55.8% and 67.8%, respectively. As for semi-quantitative analysis, the T/G ratios of inflammatory lesions, low-grade gliomas and high-grade gliomas were 0.88 ± 0.24, 1.04 ± 0.43 and 1.43 ± 0.49, respectively. One-way ANOVA revealed that the T/G ratios of high-grade gliomas were significantly higher than those of low-grade gliomas and inflammations (P < 0.05), but there was no statistical difference between low-grade gliomas and inflammations (P = 0.118). Among the inflammatory lesions, T/G ratios were not statistically different between infectious and demyelinating lesions (P > 0.05). ROC curve analysis showed that the optimal cut-off value of T/G ratio in distinguishing gliomas from inflammations was 1.21 with the AUC 0.78. The sensitivity, specificity, accuracy, PPV and NPV were 52.9%, 94.4%, 65.3%, 95.7% and 45.9%, respectively. ROC curve analysis showed that the optimal cut-off value of T/G ratio in distinguishing high-grade gliomas from low-grade gliomas was 1.06 with the AUC 0.78. The sensitivity, specificity, accuracy, PPV and NPV were 81.5%, 67.7%, 76.5%, 81.5% and 67.7%, respectively. ROC curve analysis showed that the optimal cut-off value of T/G ratio in distinguishing high-grade gliomas from low-grade gliomas and inflammations was 1.19 with the AUC 0.84. The sensitivity, specificity, accuracy, PPV and NPV were 70.4%, 85.1%, 78.5%, 79.2% and 78.1%, respectively.Conclusions: 13N-ammonia imaging is effective in distinguishing high-grade gliomas from low-grade gliomas and inflammations, but its role in the differential diagnosis of low-grade gliomas and brain inflammatory lesions is limited, and the accuracy needs to be improved. [ABSTRACT FROM AUTHOR]

Background. Portal hypertensive gastropathy (PHG) is a common anomaly with potential for bleeding found in portal hypertension. Blood ammonia levels correlate well with liver disease severity and existence of portosystemic shunts. Increased ammonia results in vasodilation and hepatic stellate cell activation causing and exacerbating portal hypertension. Objective. To assess the relation of blood ammonia to the presence and severity of portal hypertensive gastropathy in cirrhosis. Methods. This cross-sectional study included 381 cirrhotics undergoing screening for esophageal varices (EV) divided into a portal hypertensive gastropathy group (203 patients with EV and PHG), esophageal varix group (41 patients with EV but no PHG), and control group (137 patients with no EV or PHG). A full clinical examination, routine laboratory tests, abdominal ultrasonography, child score calculation, and blood ammonia measurement were performed for all patients. Results. Blood ammonia, portal vein, splenic vein, and splenic longitudinal diameters were significantly higher and platelet counts lower in patients with EV and EV with PHG than controls. Patients having EV with PHG had significantly higher bilirubin and ammonia than those with EV but no PHG. Severe PHG was associated with significantly higher ammonia, EV grades, and superior location and a lower splenic longitudinal diameter than mild PHG. The PHG score showed a positive correlation with blood ammonia and a negative correlation with splenic longitudinal diameter. Conclusions. Blood ammonia levels correlate with the presence, severity, and score of portal hypertensive gastropathy in cirrhosis suggesting a causal relationship and encouraging trials of ammonia-lowering treatments for the management of severe PHG with a tendency to bleed. [ABSTRACT FROM AUTHOR]

To investigate the role of betaine in the intestinal functions of high-salt stressed rats, 32 four-week-old male Sprague–Dawley rats weighing 128.0 (SD 5.06) g were randomly allotted to four groups. The control group was fed with standard chow diet (0.4% NaCl), while the treatment groups were fed a high-salt diet (4.0% NaCl) supplemented with betaine at 0.0%, 0.5%, and 1.0%, respectively. The experiment lasted 28 days. The results showed that rats in the high-salt stressed groups had a significant increase in both water intake and kidney index (p < 0.05). The level of cortisol (COR) was increased in the high-salt stressed rats (p < 0.05), and returned to normal levels with betaine supplementation (p < 0.05). Aldosterone (ALD) was decreased in all high-salt diet groups (p < 0.05). Betaine supplementation decreased antidiuretic hormone (ADH) levels significantly (p < 0.05). High salt stress decreased the activities of amylase, lipase, trypsin, and chymotrypsin in the small intestinal luminal contents (p < 0.05), however, these activities increased with betaine supplementation (p < 0.05). The gut villus height of small intestine was significantly decreased in the high-salt diet group (p < 0.05). However, they were higher in the betaine supplementation groups than in the control group (p < 0.05). A similar result was observed in the ratio of villus height to crypt depth (p < 0.05). Both alpha diversity indexes and beta diversity indexes showed that high salt stress decreased the diversity of intestinal microbiota, while supplementation with betaine counteracted the negative effect. In conclusion, the results indicate that betaine improves intestinal function by enhancing the digestive enzymes, ameliorating intestinal morphology, and enriching intestinal microbiota of high-salt stressed rats. [ABSTRACT FROM AUTHOR]

Abstract: Invariant NKT (iNKT) cells are a distinct subset of T cells that exert Janus‐like functions in vivo by producing IFN‐γ and IL‐4. Sodium chloride modulates the functions of various immune cells, including conventional CD4+ T cells and macrophages. However, it is not known whether sodium chloride affects iNKT cell function, so we addressed this issue. Sodium chloride inhibited IFN‐γ, but not IL‐4, production by iNKT cells upon TCR or TCR‐independent (IL‐12 and IL‐18) stimulation in a dose‐dependent manner. Consistently, sodium chloride reduced the expression level of tbx21, but not gata‐3, in iNKT cells stimulated with TCR engagement or IL‐12 + IL‐18. Sodium chloride increased phosphorylated p38 expression in iNKT cells and inhibitors of p38, NFAT5, SGK1, and TCF‐1 restored IFN‐γ production by iNKT cells stimulated with sodium chloride and TCR engagement. Furthermore, adoptive transfer of iNKT cells pretreated with sodium chloride restored antibody‐induced joint inflammation to a lesser extent than for untreated iNKT cells in Jα18 knockout mice. These findings suggest that sodium chloride inhibits IFN‐γ production by iNKT cells in TCR‐dependent and TCR‐independent manners, which is dependent on p38, NFAT5, SGK1, and TCF‐1. These findings highlight the functional role of sodium chloride in iNKT cell‐mediated inflammatory diseases. [ABSTRACT FROM AUTHOR]

Ammonia is diffused and transported across all plasma membranes. This entails that hyperammonemia leads to an increase in ammonia in all organs and tissues. It is known that the toxic ramifications of ammonia primarily touch the brain and cause neurological impairment. However, the deleterious effects of ammonia are not specific to the brain, as the direct effect of increased ammonia (change in pH, membrane potential, metabolism) can occur in any type of cell. Therefore, in the setting of chronic liver disease where multi-organ dysfunction is common, the role of ammonia, only as neurotoxin, is challenged. This review provides insights and evidence that increased ammonia can disturb many organ and cell types and hence lead to dysfunction. [ABSTRACT FROM AUTHOR]

ABSTRACT In ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in Paramecium tetraurelia, Paramecium multimicronucleatum and Tetrahymena thermophila and in part also in Euplotes raikovi. Electrophysiology of ciliary activity in Paramecium spp. is a most successful example. Established signalling mechanisms include plasmalemmal ion channels, recently established intracellular Ca2+-release channels, as well as signalling by cyclic nucleotides and Ca2+. Ca2+-binding proteins (calmodulin, centrin) and Ca2+-activated enzymes (kinases, phosphatases) are involved. Many organelles are endowed with specific molecules cooperating in signalling for intracellular transport and targeted delivery. Among them are recently specified soluble N-ethylmaleimide-sensitive factor attachment protein receptors ( SNAREs), monomeric GTPases, H+-ATPase/pump, actin, etc. Little specification is available for some key signal transducers including mechanosensitive Ca2+-channels, exocyst complexes and Ca2+-sensor proteins for vesicle-vesicle/membrane interactions. The existence of heterotrimeric G-proteins and of G-protein-coupled receptors is still under considerable debate. Serine/threonine kinases dominate by far over tyrosine kinases (some predicted by phosphoproteomic analyses). Besides short-range signalling, long-range signalling also exists, e.g. as firmly installed microtubular transport rails within epigenetically determined patterns, thus facilitating targeted vesicle delivery. By envisaging widely different phenomena of signalling and subcellular dynamics, it will be shown ( i) that important pathways of signalling and cellular dynamics are established already in ciliates, ( ii) that some mechanisms diverge from higher eukaryotes and ( iii) that considerable uncertainties still exist about some essential aspects of signalling. [ABSTRACT FROM AUTHOR]

Cirrhosis leads to portal hypertension and vascular abnormalities in multiple vascular beds. There is intense vasoconstriction in the liver and the kidneys, but also vasodilation in the other vascular beds, including the periphery, lungs, brain, and mesentery. The derangement in each of these beds leads to specific clinical disease. The vasoconstrictive phenotype in the liver ultimately leads to clinical portal hypertension, and is caused by an imbalance of vasoconstrictive and vasorelaxing molecules, which will be the focus of this review. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study was designed to determine possible protective effect of betaine treatment against oxidative injury in pulmonary tissue induced with thermal trauma. METHODS: Under ether anesthesia, shaved dorsum of Wistar albino rats was exposed to a 90°C water bath for 10 seconds to induce burn injury. Betaine was administered orally (250 mg/kg) for a period of 21 days before burn injury, and single dose of betaine was administered after thermal injury. Control group rats were exposed to 25°C water bath for 10 seconds. Upon conclusion of experiment, rats were decapitated and blood was collected for analysis of pro-inflammatory cytokines and lactate dehydrogenase (LDH) activity. Lung tissue samples were taken to determine malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO), and Na+K+-ATPase activity, in addition to histological analysis. RESULTS: Burn injury caused significant increase in both cytokine levels and LDH activity. In lung samples, raised MDA levels, MPO activity, and reduced GSH levels and Na+/K+-ATPase activity were found due to burn injury. CONCLUSION: Treatment of rats with betaine significantly restored GSH level and Na+K+-ATPase activity, and decreased MDA level and MPO activity. According to the findings of the present study, betaine significantly diminishes burn-induced damage in tissue. [ABSTRACT FROM AUTHOR]

Liver myofibroblasts (MFB) are crucial mediators of extracellular matrix (ECM) deposition in liver fibrosis. They arise mainly from hepatic stellate cells (HSCs) upon a process termed "activation." To a lesser extent, and depending on the cause of liver damage, portal fibroblasts, mesothelial cells, and fibrocytes may also contribute to the MFB population. Targeting MFB to reduce liver fibrosis is currently an area of intense research. Unfortunately, a clog in the wheel of antifibrotic therapies is the fact that although MFB are known to mediate scar formation, and participate in liver inflammatory response, many of their molecular portraits are currently unknown. In this review, we discuss recent understanding of MFB in health and diseases, focusing specifically on three evolving research fields: metabolism, autophagy, and epigenetics. We have emphasized on therapeutic prospects where applicable and mentioned techniques for use in MFB studies. Subsequently, we highlighted uncharted territories in MFB research to help direct future efforts aimed at bridging gaps in current knowledge. [ABSTRACT FROM AUTHOR]