bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gut Microbial Metabolite TMAO Induces Endothelial Dysfunction by Activating the HMGB1/TLR‐4 Signalling Pathway
Authors: Singh Gurinder Bir , Mohammad Razia S. , Kshirasagar Naresh , Zhang Yang , McConnell Bradley K. , Li Pin‐Lan , Boini Krishna M. , Koka Saisudha 
Published: June 2021

The intestinal microbe derived metabolite trimethylamine N‐oxide (TMAO) is implicated in the pathogenesis of cardiovascular diseases. However, the molecular mechanisms of how TMAO induces atherosclerosis and CVD progression are still unclear. In this regard, high‐mobility group box protein 1 (HMGB1), an inflammatory mediator, has been reported to destroy cell‐cell junctions, resulting in vascular endothelial hyper permeability leading to endothelial dysfunction. The present study tested whether TMAO associated endothelial dysfunction results via HMGB1 activation in in vitro and in vivo models. Biochemical and RT‐PCR analysis showed that TMAO increased the HMGB1 expression in dose dependent manner in endothelial cells compared to control cells. However, prior treatment with glycyrrhizin, an HMGB1 binder abolished the TMAO‐induced HMGB1 production in endothelial cells. Furthermore, western blot and immunofluorescent analysis showed significant decrease in the expression of cell‐cell junction proteins ZO‐1, ZO‐2, Occludin and V‐cadherin in TMAO treated endothelial cells compared to control cells. However, prior treatment with glycyrrhizin attenuated the TMAO‐induced cell‐cell junction proteins disruption. In addition, TMAO induced the HMGB1 expression through TLR‐4 signalling pathway in endothelial cells. In in vivo studies, C57BL/6J wild mice were treated with 3 % choline chloride in drinking water to produce enhanced TMAO levels in plasma. Real time PCR analysis showed that HMGB1, TLR‐4 and inflammatory markers (ICAM & VCAM) were significantly increased in carotid arteries of choline treated mice compared to control mice. In addition, it was also found that collagen I and III expression (fibrotic markers) were significantly increased in carotid arteries of choline treated mice. In conclusion, our results suggested that TMAO modulated endothelial cells phenotype via activating HMGB1 associated TLR‐4 signalling pathway.Support or Funding Informationsupported by NIH grant, DK104031This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Short and Long‐Term Effects of Food Restriction on Body Composition and the Renin Angiotensin System
Authors: Souza Aline , West Crystal A. , Campos Glenda , Pai Amrita V. , Ji Hong , Sandberg Kathryn 
Published: June 2021

IntroductionIndividuals who experience severe food restriction (FR) diet are at increased risk for developing cardiovascular disease during the FR period and also long term well after the FR period has ended. Abnormalities in the heart, vascular system and kidneys including hypotension, bradycardia and mitral valve prolapse are common problems in individuals who have experienced a FR. Unfortunately, the long‐term risk for cardiovascular and renal disease due to earlier exposure to FR is an understudied problem and there are no known therapeutic strategies designed to prevent the increased risk after recovery from the FR period(s). The goal of this study was to determine the short and long term consequences of a severe FR diet on body composition and sodium and potassium balance.MethodsFour month old (mo) female Fischer rats were divided into a control (CT) group that had access to food ad libitum and a FR group that received 40% of the normal daily food intake. After 2 weeks, the FR rats received chow ad libitum for 1 month. The FR group were placed in metabolic cages on day 1 through day 4 and on day 14 of the restricted diet through day 4 of the recovery phase to collect urine and to determine the sodium & potassium balance.ResultsAfter 2 weeks, the FR group had an 18% reduction in body weight (BW) and a 50% reduction in water intake compared to the CT rats. In addition, plasma volume (p=0.03), blood pressure (p=0.03), heart rate (p=0.03), kidney weight, and kidney protein were all reduced and angiotensin (Ang) II (p<0.05) and angiotensinogen (p<0.001) were increased in the plasma. No differences were observed in plasma aldosterone and potassium or in urine protein. The plasma sodium concentration was increased in the FR rats. While the FR animals remained in sodium balance during the first 4 days of the diet, these animals were in negative balance for potassium (p<0.05) returning to balance on the 2nd day. The estrous cycle was disrupted after 3 days on the diet with the animals remaining in diestrus and returning to the ovulatory phase only after 7 days into the recovery period. The ad libitum diet also caused a positive balance for potassium during the 1st day without any effect on sodium balance. The rats did not recover their normal BW until 21 days into the recovery phase. Body fat recovered within 1 week while the % lean body mass did not recover until 28 days of the recovery phase.ConclusionSevere FR causes major changes in the renin angiotensin system, potassium balance, endocrine status and body composition. These effects are long lasting and likely contribute to the long term adverse consequences of exposure to a single period of severe food restriction.Support or Funding InformationTL1‐TR001431 (AVP), UL1‐TR001409 (KS) and R01‐HL119380 (KS, HJ).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
AMPK as a metabolic sensor regulates inflammatory response during ischemic insults
Authors: Li Ji , Chen Xu , Cates Courtney , Rousselle Thomas , Li Xuan 
Published: June 2021

IntroductionAMP‐activated Protein Kinase (AMPK) is a stress‐activated kinase that protects against cardiomyocyte injury via modulating substrate metabolic shift between glucose and fatty acid during ischemia and reperfusion. c‐Jun N‐terminal kinase (JNK), a mitogen activated protein kinase, is activated by ischemia and reperfusion for modulating inflammatory response. NF‐κB is an important transcription factor involved in inflammation cascade during ischemia and reperfusion injury.Methods and ResultsThe intrinsic activation of AMPK attenuates inflammation occurred during ischemia/reperfusion through modulating the JNK mediated NF‐κB signaling pathway. Rat cardiac myoblast H9c2 cells were subjected to hypoxia and/or reoxygenation to investigate the signal transduction that occurred during myocardial ischemia/reperfusion. Mitochondrial function was measured by the Seahorse XF24 V7 PS system. Hypoxia treatment triggered AMPK activation in H9c2 cells in a time dependent manner. Inhibition of hypoxic AMPK activation by pharmacological approach (Compound C) or siRNA knockdown of AMPK α catalytic subunits caused dramatic augments in JNK activation, inflammatory NF‐κB phosphorylation, and apoptosis during hypoxia and reoxygenation. Inhibition of AMPK activation significantly impaired mitochondrial function and increased the generation of reactive oxygen species (ROS) during hypoxia and reoxygenation. In contrast, pharmacological activation of AMPK by a diabetes drug metformin significantly inhibited mitochondrial permeability transition pore (mPTP) opening and ROS generation. Moreover, AMPK activation significantly attenuated JNK‐NF‐κB signaling cascade and inhibited mRNA levels of pro‐inflammatory cytokines such as TNF‐α and IL‐6 during hyopoxia/reoxygenation in H9c2 cells. Intriguingly, both pharmacologic inhibition of JNK by JNK‐IN‐8 and siRNA knockdown of JNK signaling pathway attenuated NF‐κB phosphorylation and apoptosis but did not affect AMPK activation in response to hypoxia and reoxygenation. The results indicate that AMPK as a metabolic sensor regulates substrate metabolism and maintains the integrity of mitochondria in order to limit the inflammatory response during ischemia and reperfusion stress conditions.ConclusionsAMPK activation regulates substrate metabolism and modulates JNK‐NF‐kB signaling cascade during hypoxia and reoxygenation stress conditions. Cardiac AMPK activation plays a critical role in maintaining mitochondrial function and inhibiting the inflammatory response caused by ischemic insults.Support or Funding InformationAmerican Diabetes Association 1‐17‐IBS‐296, NIH R01AG049835, R01HL12587701, P01HL051971, and P20GM104357This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Age‐related dysfunction in the satellite cell niche
Authors: Thomas Aaron , Nederveen Joshua , Snijders Tim , Joanisse Sophie , Bell Kirsten , Phillips Stuart , Kumbhare Dinesh , Parise Gianni 
Published: June 2021

Skeletal muscle satellite cells (SC) are important for maintenance and repair of myofibers. SC function and responsiveness is regulated, at least in part, through interactions with niche components in which they reside. Recent evidence suggests that structural changes occur in the SC niche as a function of aging. In the present study, we aimed to investigate whether age has an impact on the properties of the SC niche. Muscle biopsies were obtained from the vastus lateralis of previously untrained but otherwise healthy young men (YM: 21±0.4 yrs; n=10) and old men (OM: 66±0.9 yrs; n=11) at rest. In addition, OM (n =10) performed a single bout of resistance exercise and additional muscle biopsies were taken 24 h and 48 h post‐exercise. Skeletal muscle SC niche measurements were assessed using high resolution immunofluorescent and confocal microscopy. We report changes in the muscle SC niche with aging and that many of these differences are primarily associated with type II fibres. Type II SC niche laminin thickness was significantly greater in OM (1.86 ± 0.06 μm) as compared to YM (1.55 ± 0.09 μm, p<0.05). Mean intensity of collagen IV was significantly lower in OM (92 ± 10 a.u) as compared to YM (512 ± 17 a.u, p<0.05). In OM, the fibrotic index as measured by Masson's trichrome staining was greater (3.6 ± 0.5 %) at baseline, as compared to YM (2.0 ± 0.5 %; p<0.05). We also observed the presence of SC fully incarcerated by the basal lamina. At baseline, 100% of OM possessed SC that were incarcerated, as compared to ~40% of YM. The percentage of SC in mixed muscle that were incarcerated by laminin was greater in OM (19.0 ± 1.6%) as compared to YM (7.2 ± 2.1; p<0.05). Although this phenomenon was present in both Type I and Type II fibres, it appeared exaggerated in Type I fibres (OM: 28.4 ± 8.2%, YM: 3.6 ± 2.1%; p<0.05). In all cases the greatest proportion of active SC were found in the non‐incarcerated population, whereas incarcerated cells were less likely to activate (24 h post exercise – Non‐incarcerated:32 ± 6% active, Incarcerated: 8 ± 2% active, p<0.05). Consistent with this, at 24 h, there was a significantly lower number of quiescent SC in the non‐incarcerated condition (62 ± 7 %) as compared to the incarcerated condition (92 ± 4%, p<0.05). Additional evidence of age‐related dysfunction includes larger myonuclear CSA, increased expression of COL4α1 mRNA and Laminin subunits α2 and β1 was significantly greater in OM as compared to YM. Together this data suggests there are age‐related changes in the niche that are potentially detrimental to SC function and skeletal muscle health.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Dynamics of blood lactate concentration during recovery period of short duration‐high intensity exercise in acute hypoxia or normoxia
Authors: Takei Naoya , Kakinoki Katsuyuki , Hatta Hideo 
Published: June 2021

We studied dynamics of blood lactate concentration during recovery period of short duration‐high intensity exercise in acute hypoxia or normoxia. University track and field athletes were recruited for single‐blind randomized crossover designed study. All subjects completed wingate test in both acute hypoxia (FiO2=0.145) and normoxia (FiO2=0.21). Two wingate tests were separated at least 48 hours. After 10 min cycling warm‐up (100 W), subjects took 5 min rests and then conducted 30 sec wingate tests. After the wingate test, subjects of both conditions took 30 min rests in normoxia. Blood samplings were conducted 1 min before and, 0.5, 1, 2, 3, 4, 5, 7, 10, 20 and 30 min after the wingate tests to examine the blood lactate concentration. Peak power output (PPO), mean power output (MPO) and fatigue index (FI) were not different in both condition (PPO; 984.3±49.3 W and 971.0±32.1 W, MPO; 674.3±37.4 W and 680.0±36.3 W, FI; 49.2±7.1% and 49.6±5.2%, normoxia and hypoxia respectively). The AUC of blood lactate, when examined pre to 10 min values, was significantly higher in acute hypoxia than normoxia (p<0.05). The rates of reduction of blood lactate concentration was higher in hypoxia than normoxia(p<0.05, 0.42±0.02 and 0.28±0.03 mmol/L/min, respectively). These results suggested that muscle glycogen breakdown was higher in acute hypoxia than normoxia in spite of same wingate test performances. It also suggests that lactate oxidation may be higher in acute hypoxic group when resting at normoxia.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Comparison of Measures of Compensatory Reserve and Tissue Oxygen in Differentiating Tolerance to Simulated Hemorrhage
Authors: Schlotman Taylor E. , Howard Jeffrey T. , Convertino Victor A. 
Published: June 2021

BackgroundWe previously reported that average measurements of compensatory reserve (CRM) and muscle oxygen saturation (SmO2) obtained from a large cohort of humans provided earlier indication of reduced central blood volume than standard vital signs (e.g., blood pressure, heart rate, arterial oxygen saturation). Additionally, CRM was more sensitive and specific in earlier prediction of decompensation than SmO2 overall.ObjectiveIn the present study, we hypothesized that CRM derives its superior predictive qualities from its ability to differentiate between individuals with high (HT) and low (LT) tolerance to central hypovolemia compared with measures of SmO2.MethodsContinuous noninvasive measures of CRM (calculated from feature changes in the photoplethysmographic arterial waveforms) were collected from 55 healthy volunteer subjects before and during stepwise lower body negative pressure (LBNP) to the point of presyncope. Near infrared spectroscopy was used on the forearm to obtain measures of deep SmO2, hydrogen ion concentration ([H+]), and hemoglobin volume (HbT; decreases reflect vasoconstriction). Using a progressively increasing stepwise protocol, tolerance group was defined by those subjects who did (HT) or did not (LT) complete 60 mmHg LBNP. Data were analyzed using generalized estimating equations (GEE) to account for the repeated measures design.ResultsOf 55 participants, there were 35 (64%) HT and 20 (36%) LT, 26 (47%) males and 29 females (53%), with a mean age of 28 years (SD=7), height of 172 cm (SD=10) and weight of 72 kg (SD=15). CRM decreased by 97% in a linear fashion across progressive LBNP levels from baseline to −90 mm Hg, while SmO2 decreased by only 39% from baseline to −90 mm Hg. The slope for CRM values across progressive LBNP levels differed significantly between LT and HT individuals (slope difference −0.14; p=0.03). The slope for SmO2 values did not differ between LT and HT individuals across LBNP levels (slope difference=0.06; p=0.18).ConclusionConsistent with our hypothesis, CRM exhibited greater reduction across progressive LBNP levels than SmO2. These data support the notions that: 1) CRM can enable more accurate triage of casualties than SmO2 due to superior ability to differentiate those individuals at highest risk for shock; and 2) continuous monitoring of CRM can allow for earlier detection of continued casualty deterioration.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Bicarbonate is required for proliferation of pulmonary endothelial cells
Authors: Sayner Sarah L. , Maulucci Marcy , Harvell Tyler 
Published: June 2021

RationaleThe second messenger cAMP is widely known to regulate proliferation in numerous cell types. Many of these studies implicate cAMP generated by membrane‐bound cyclases (AC1‐9). While these membrane‐bound ACs generate cAMP in the near membrane compartment, cAMP can also be generated in unique subcellular compartments by the soluble adenylyl cyclase (sAC or AC10). Soluble AC localizes to the cytosol as well as organelles, such as the mitochondria, and is uniquely stimulated by bicarbonate to generate cAMP. Recently, AC10 was observed to be overexpressed in prostate carcinoma, suggesting a role for AC10 in cellular proliferation; however, the independent role of bicarbonate in proliferation has not been investigated. Thus, we tested the hypothesis that bicarbonate is required for proliferation of pulmonary endothelial cells.MethodsPulmonary microvascular endothelial cells (PMVECs) and pulmonary artery endothelial cells (PAECs) were seeded at 100, 000 cells per well in media with and without bicarbonate. The cells were counted for seven consecutive days to generate growth curves and blood gas analysis performed to determine pH, pO2, pCO2, and HCO3− concentrations of the media. Additionally, a separate set of PMVECs were seeded at 100, 000 cells per well in bicarbonate free media and bicarbonate added back to the media after 24, 48, 72, 96, 120, 144, and 168 hours and counted for five days following bicarbonate add back.ResultsGrowth curves revealed that PMVECs and PAECs seeded in the bicarbonate‐containing media entered into log phase growth followed by a plateau phase at cell confluence; however, PMVECs and PAECs seeded in the bicarbonate free media did not enter log phase growth nor reach confluence. When bicarbonate was added back to PMVECs initially grown in a bicarbonate free environment, the cells proliferated to numbers comparable to PMVECs seeded in bicarbonate containing media throughout the growth curve; however, if PMVECs were incubated in bicarbonate free media for more than 96 hours, these cells did not enter into log phase growth and did not form a confluent monolayer.ConclusionThese data reveal a requirement for bicarbonate for proliferation of pulmonary endothelial cells, since neither PAECs nor PMVECs formed confluent monolayers in the absence of bicarbonate.Support or Funding InformationNIH 121513This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mesenchymal Stromal Cell Microparticles Enhance Lung Endothelial Barrier Through CD44 and the S1P/ceramide Rheostat
Authors: Maishan Mazharul , McVey Mark J. , Lee Warren L. , Curley Gerard F. , Kuebler Wolfgang M. 
Published: June 2021

IntroductionAcute respiratory distress syndrome (ARDS) is a fatal condition characterized by hyperinflammation and pulmonary microvascular leak. Treatment is only supportive with no pharmacological cure. Recently, mesenchymal stromal/stem cells (MSCs) have emerged as potential therapy, but greater knowledge on their mechanism(s) of action could yield development of cell‐free therapeutics.ObjectiveTo determine if MSC‐produced microparticles (MPs) ameliorate endothelial barrier disruption and identify their biomolecular contents responsible for such therapeutic effect.MethodsTo re‐capitulate lung capillary leak in ARDS, primary human pulmonary microvascular endothelial cell (HPMEC) monolayers grown on Transwell inserts were injured with thrombin to induce barrier disruption as measured by transendothelial electrical resistance (TEER). MPs were purified out of conditioned medium produced by MSCs either stimulated with Ca2+ ionophore or unstimulated. MPs were administered to treat thrombin‐injured HPMEC monolayers; surface markers were compared by flow cytometry and lipid content analyzed by HPLC‐MS.ResultsMPs from unstimulated MSCs enhanced HPMEC barrier function and TEER recovery after thrombin injury, while MPs from stimulated MSCs were injurious. Stimulated MSCs produced MPs with significantly less surface CD44. Antibody blockade of CD44 on unstimulated MPs eliminated their therapeutic effect on HPMEC monolayers. Moreover, stimulated MPs had significantly more total ceramides and less sphingosine‐1‐phosphate (S1P) than unstimulated MPs. Ceramide degradation by neutral ceramidase blunted the injurious effect of stimulated MPs. The therapeutic function of unstimulated MPs was eliminated with ceramide over‐production by acid sphingomyelinase or S1P degradation by S1P lyase.ConclusionThese results show MSC‐produced MPs were therapeutic after lung capillary endothelial barrier disruption. Beneficial effects were associated with surface CD44 and greater ratio of S1P:ceramide content. This knowledge provides a mechanistic basis for development of MSC‐based cell‐free therapeutics.Support or Funding InformationThis work was supported by Ontario Research Fund and Canadian Institutes of Health Research.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Myeloperoxidase‐derived 2‐Chlorofatty Acids: Accumulation in Rat and Human Sepsis, and Association with Acute Respiratory Distress Syndrome Mortality in Human Sepsis
Authors: Pike Daniel , Nuala Meyer , Reilly John , Feng Rui , Christie Jason , Albert Carolyn , Hartman Celine , Franke Jacob , McHowat Jane , Ford David 
Published: June 2021

Neutrophilic inflammation is a component of sepsis‐associated acute respiratory distress syndrome (ARDS). Neutrophil myeloperoxidase (MPO) activity produces HOCl, which leads to increased plasma 2‐chlorofatty acid (2‐ClFA) levels due to HOCl targeting plasmalogens. Thus, these studies were designed to investigate the role of 2‐ClFA in ARDS during sepsis. In patients with sepsis (n=198), free 2‐ClFA levels were significantly associated with ARDS (odds ratio (OR) 1.87 (95% CI 1.41, 2.49); p < 0.001), and with 30‐day mortality (OR 1.38 (95% CI 1.11, 1.72); p=0.004), for each log increase in free 2‐chlorostearic acid. Of considerable interest, plasma 2‐ClFA levels correlated with plasma levels of angiopoietin‐2, E‐selectin, and soluble thrombomodulin suggesting 2‐ClFAs may mediate endothelial dysfunction in human sepsis. Further studies with human lung microvascular endothelial cells (HMVEC‐L) showed 2‐ClFA treatment resulted in increased adhesion molecule surface expression; increased angiopoietin‐2 release and dose‐dependent endothelial permeability. In contrast, these changes were not observed in endothelial cells treated with non‐chlorinated palmitic acid. Next, the cecal slurry model of rat sepsis was investigated. Injecting rats with 15ml of cecal slurry/kg resulted in mortality within 26h accompanied by significant increases in 2‐ClFA levels in the plasma and lung in comparison to rats injected with vehicle. The ultimate goal of these studies will be to test therapeutic agents that prevent chlorinated lipid‐caused organ injury including ARDS during sepsis. Collectively, these studies suggest that 2‐ClFAs derived from neutrophil MPO‐catalyzed oxidation contribute to pulmonary endothelial injury and ARDS, and have prognostic utility in sepsis‐associated ARDS.Support or Funding InformationThis study was supported by NIH grants R01GM115553 (to DAF and JM). and R01HL122474 (to NJM).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.