bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isoalantolactone inhibits LPS‐induced inflammatory responses in macrophages
Authors: Wang Ping‐Chun , Li Chia‐Yang 
Published: June 2021

Isoalantolactone (ISO) is a main sesquiterpene lactone isolated from Inula helenium, which has been reported to have anti‐inflammatory and anti‐oxidative effects. However, the effect of ISO on LPS‐induced inflammatory responses has not been extensively studied. Herein we examine the anti‐inflammatory effects of ISO by LPS‐activated murine macrophages, J774A.1 cells. Cell viability was examined by MTT assay. The production of nitric oxide (NO) was analyzed using Griess reagent assay. The expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) was detected by Western blot. The secretion of pro‐inflammatory cytokines including tumor necrosis factor‐alpha (TNF‐α) and interleukin‐6 (IL‐6) was determined using ELISA. Our experimental results showed that dose of ISO under 10 μM had no toxicity in J774A.1 cells. To avoid the toxic effect of ISO, the dose of ISO used in this study was less than or equal to 10 μM. Our experimental results indicated that ISO inhibits the production of NO, decreases the expression of iNOS and COX‐2, and attenuated the secretion of TNF‐α and IL‐6 in J774A.1 cells. Collectively, our experimental results demonstrated that ISO suppresses LPS‐induced inflammatory responses in macrophages. These results suggest that ISO might has potential against LPS‐induced overactive inflammation.Support or Funding InformationThis study was supported by the Ministry of Science and Technology, Taiwan, R.O.C. (Grant No. MOST 107‐2320‐B‐037‐019).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Renal collecting duct plasticity revealed by intercalated cell lineage tracing
Authors: Picard Nicolas , Hennings J. Christopher , Godefroy Marion , Trepiccione Francesco , Huebner Antje K. , Eladari Dominique , Huebner Christian 
Published: June 2021

The connecting tubule and collecting duct in the distal nephron play an essential role for acid‐base and NaCl homeostasis. Their epithelium comprises two main cell types, i.e. principal cells and intercalated cells (IC). At least two types of IC, type A‐IC and type B‐IC are distinguished. While A‐IC express the V‐type ATPase at their apical side, it localizes basolaterally in B‐IC. Thus, A‐IC can actively secrete H+, while B‐IC can mediate bicarbonate secretion via apical pendrin. Adaptation to a change in acid/base status is partly achieved by varying the numbers of A‐IC and B‐IC cells. For example, a chronic metabolic acidosis or LiCl administration promote an increase in A‐IC while the number of B‐IC is decreased. Based on these findings it is assumed that the plasticity of the distal nephron might be explained in part by a conversion of B‐IC into A‐IC or principal cell to A‐IC or vice versa.To test this hypothesis, we crossed a mouse reporter line with a Cre‐line either specific for A‐ or B‐IC. The expression of Cre‐recombinase results in the excision of a floxed STOP cassette, thus, inducing constitutive expression of TdTomato. In both mouse models, TdTomato positive cells were characterized by confocal microscopy and immunostaining with IC and principal cell markers. In untreated adult mice, the fluorescent tag was restricted to each IC population with no leakiness in PC or other renal epithelial cells. In chronic metabolic acidosis induced by NH4Cl loading or during LiCl treatment, no transition of B‐IC TdTomato+ cells to A‐IC was observed. In a similar setting of metabolic alkalosis, A‐IC tomato‐td mice did not transform in B‐IC when challenged with NaHCO3 load. In the recovery of LiCl treatment in A‐IC tagged mouse, we could detect that some principal cells acquire the TdTomato mainly in the medullary collecting duct.In conclusion, A‐ and B‐IC lineage tracing in the mouse suggest that conversion either from A‐to B‐IC or from B‐ to A‐IC does not occur in the adult mouse kidney. We observed the transition from A‐IC to principal cells in the medulla which suggests a particular plasticity between this two cell types.Support or Funding InformationNP is funded by Agence National Recherche grant ANR‐16‐CE14‐0031 and ANR‐15‐CE14‐0024. CH is funded by DFG grant HU 800/7‐2This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intercalated Cell Claudin‐4 knockout mice display abnormal renal sodium and potassium conservation and hypercalciuria
Authors: Cordat Emmanuelle , Ullah AKM Shahid , Fernandes Daphne , Dimke Henrik , Alexander R. Todd 
Published: June 2021

Distal Renal tubular acidosis is a disease characterized by the inability to acidify the urine below a pH of 5.5, metabolic acidosis, hypokalemia and hyperchloremia. It is caused by mutations in genes encoding the v‐B1‐H+‐ATPase, the cytosolic carbonic anhydrase II or the kidney anion exchanger 1 (kAE1) in the renal collecting duct (CD). We recently discovered that kAE1 physically and functionally interacts with the tight junction protein claudin‐4 (Cldn‐4). This protein is expressed in principal (PC) and intercalated cells (IC) and forms a paracellular chloride pore and sodium barrier. With the aim to decipher the physiological role of the kAE1/Cldn‐4 interaction, we generated and characterized IC‐specific Cldn‐4 KO mouse. The knockout mice displayed a 30% reduction in Cldn‐4 abundance in isolated CD, in agreement with the reported IC/PC ratios. Although the KO animals developed normally and did not display an obvious phenotype, they presented a higher urinary calcium concentration at steady state than control animals. Feeding the mice a low NaCl diet caused the Cldn‐4 KO animals to have a more alkaline and dilute urine than control animals. Upon acid challenge, the Cldn‐4 KO mice excreted less urinary sodium and potassium compared with control animals. These results suggest that tight junction Cldn‐4 contributes to the maintenance of appropriate electrolyte and acid‐base balance.Support or Funding InformationThis work was funded by the Canadian Institutes of Health Research, the Kidney Foundation of Canada, the Women and Children's Health Research Institute (supported by the Stollery Children's Hospital Foundation), Alberta Innovates and the Canada Foundation for InnovationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Evolution of Air‐breathing Revised
Authors: Damsgaard Christian , Baliga Vikram B. 
Published: June 2021

The evolution of air‐breathing represents one the most pronounced changes in the cardio‐respiratory physiology of vertebrates. While a lot is known about the physiological transitions required for air‐breathing evolution, there is limited information available on the evolutionary dynamics in breathing mode. Previous analyses suggest 34–67 independently origins of air‐breathing within extant vertebrates, but nothing is known about when in geological time air‐breathing originated or if air‐breathing has been secondarily lost. This study aimed to 1) provide more robust estimates on the number of air‐breathing origins, 2) identify if air‐breathing has been secondarily lost within clades of air‐breathing fishes, and 3) identify the timing of these events. To do this, we used an updated list of air‐breathing fishes, a fully resolved, time‐calibrated fish phylogeny and Bayesian phylogenetic comparative methods. We show that air‐breathing evolved 74–80 times within extant vertebrates, which is significantly higher the previously proposed 34–67 independent origins. Further, we show strong support for 7 secondary losses of air‐breathing, where pure water‐breathing was adapted from an air‐breathing ancestor. Finally, we show that the majority of air‐breathing clades radiated within the last 65 million years. This study adds novel dimensions to the evolution of air‐breathing and identifies an unprecedented evolutionary plasticity in breathing mode, where air‐breathing has been gained and lost repeatedly during the evolutionary history of vertebrates.Support or Funding InformationChristian Damsgaard is supported by the Carlsberg Foundation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Time of Year Has No Effect on Indicators of Insulin Resistance in Fasting Horses
Authors: Martinez‐Flores Brenda , Harms Abigail Rachel , Mofatt Cheyenne N. , Paquin Zachary W. , Guild Ayla , Johnson Kathryn M.S. 
Published: June 2021

Laminitis is a severe equine lameness associated with obesity and obese‐related conditions, such as insulin resistance. Extremely painful, laminitis typically manifests in horses in the spring and/or summer. It is unclear if insulin resistance is the mechanism that initiates the seasonal onset of laminitis or even if insulin resistance is altered seasonally in horses. To determine if insulin resistance varies throughout the year in horses, blood was collected via the jugular vein, from overnight fasted horses (n=35), from four different breeds with varying known risks for obesity‐related conditions and laminitis, (stock horses, n=11; draft/draft crosses horses, n=7; Saddlebreds, n=7; and Welsh ponies, n=10) every 60 days for a year (September 2015–July 2016). Fasting insulin resistance was determined by plasma glucose to insulin ratio (GIR=[fasting plasma glucose]/[fasting plasma insulin]) and quantitative insulin sensitivity check index (QUICKI=1/(log[fasting plasma glucose]+log[fasting plasma insulin])), with lower levels of each indicating increased insulin resistance. Neither time of year (MANOVA, F5,23=0.911, p=0.491; F5,23=1.28, p=0.307) nor breed (F5,27=0.417, p=0.091; F5,27=2.43, p=0.087) had an effect on GIR and QUICKI. Therefore, no difference in insulin resistance was detected in fasting horses throughout the year. GIR and QUICKI are commonly used in clinical settings; however, it is possible that these indicators may not accurately reflect the insulin status in horses, due to the fasted states required by these measurements. Other metrics of insulin sensitivity may need to be implemented to determine if insulin resistance is a precursor to the onset of seasonal laminitis.Support or Funding InformationThis work was supported by the Biomedical Scholars program at Beloit College.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Differential Effects of Morphine on a Dispersed Respiratory Network to Induce Respiratory Depression in Awake Mice
Authors: Varga Adrienn G. , Reid Brandon T. , Kieffer Brigitte L. , Levitt Erica S. 
Published: June 2021

Respiratory depression is the main cause of death from an opioid overdose. The reduction in respiratory rate is the result of activation of mu opioid receptors in respiratory centers, such as the pontine Kölliker‐Fuse nucleus and the medullary pre‐Bötzinger complex. The goal of this study was to directly compare the relative contribution of opioid‐sensitive neurons in the Kölliker‐Fuse nucleus and the pre‐Bötzinger complex to respiratory depression caused by systemic administration of the opioid agonist morphine in adult mice. We conditionally knocked out mu opioid receptors using virally mediated Cre expression in mice with floxed mu opioid receptors. Whole‐cell patch clamp recordings in acute brain slices showed that this approach successfully eliminates mu opioid receptor‐mediated outward currents from Kölliker‐Fuse nucleus neurons. Next, using plethysmography, we found that deletion of mu opioid receptors from either the Kölliker‐Fuse nucleus or pre‐Bötzinger complex attenuated the decrease in respiratory rate induced by an analgesic dose of morphine (10mg/kg). Administration of high doses of morphine (30mg/kg and 100mg/kg) resulted in reduced respiratory rates similar to that observed in control animals. Morphine administration also caused an increased level of irregularity in the breathing pattern with short intervals of fast and slow breathing and an increased number of apneas. These effects were dependent on the administered dose of morphine, as well as the location of mu opioid receptor removal. Our results indicate that multiple pontine and medullary respiratory groups differentially contribute to morphine‐induced respiratory depression, and none are entirely responsible for the effects of morphine.Support or Funding InformationThis work was supported by National Institutes of Health Grants DA038069 (E.S.L.) and DA05010 (B.L.K.). A.G.V. was funded by the UF Breathing Research and Therapeutics Training Program (T32 HL134621) and the Center for Respiratory Research and Rehabilitation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Translocation of bone marrow‐derived cells contribute to PVN neuroinflammation in hypoxia‐induced PH
Authors: Oliveira Aline Cristina , Kim Seungbum , Sharma Ravindra K. , Wodrich Brigitte , Kunta Avaneesh , Bryant Andrew , Zubcevic Jasenka , Richards Elaine M. , Raizada Mohan K. 
Published: June 2021

BackgroundPulmonary hypertension is a devastating disease characterized by elevated pressures in the pulmonary arterial circulation leading to right heart failure. Our previous studies have indicated that PH is not only a lung disease but a systemic disease and an altered brain‐gut‐lung axis is involved in the pathogenesis and progression of the disease.AimThis study was designed to explore the contribution of bone marrow‐derived cells to neuroinflammation in hypoxia‐induced PH modelMethodsGreen fluorescent protein (GFP) bone marrow (BM) chimeric mice (C57BL6 strain) were generated by transplanting GFP BM cells into lethally irradiated WT mice. 3 months later, subjects were exposed to chronic hypoxia (10%O2) or Normoxia for 4 weeks in a ventilated chamber (n=6–10/group). An Millar pressure catheter was used to measure pulmonary hemodynamics, microglial cells specifically stained with Iba1 and migration of BM‐derived cells were also evaluated.ResultsHypoxia induced an increase in right ventricular (RV) systolic pressure (RVSP: Normoxia (N):22.12 ± 2 mmHg vs Hypoxia (H):32.7 ± 2, p<0.001) and RV hypertrophy (RVH:N: 0.139 ± 0.09 vs H:0.201 ± 0.01, p<0.001) in chimera mice. Besides the lungs, PH also induced an increase in BM‐derived cells in the paraventricular nucleus of hypothalamus (PVN) (N 2.599:±1VsH:10.29 ±2, p<0.001) and the jejunum (N 11.08:±0.26VsH:12.65 ±0.35, p<0.001).ConclusionExposure of chimeric mice with GFP bone marrow cells to chronic hypoxia illustrate the translocation of these cells into organs we have recently described to be associated with PH; the brain and gut. This data indicates that BM‐ derived cells may contribute to the dysfunctional brain‐gut‐lung axis observed in PH.Support or Funding InformationThis research is supported by NIH grant HL102033.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Regulation of Aquaporin 1 Expression by Hypoxia‐Inducible Factors (HIFs) in Pulmonary Arterial Smooth Muscle Cells (PASMCs)
Authors: Yun Xin , Jiang Haiyang , Shimoda Larissa 
Published: June 2021

Prolonged exposure to hypoxia is a common cause of pulmonary hypertension (PH), the pathophysiology of which is characterized by sustained active vasoconstriction and pulmonary vascular remodeling. Studies have shown that HIFs, hypoxia responsive transcription factors, contribute to the development of PH. Three HIF family members have been identified, HIF‐1, HIF‐2, and HIF‐3, of which HIF‐1 and HIF‐2 are the best studied. We have shown that the water channel, aquaporin 1 (AQP1), is expressed in PASMCs and that AQP1 levels are elevated during hypoxia and mediate hypoxia‐induced cell proliferation and migration. The AQP1 promoter contains a HIF binding site, and links between HIF‐1 and AQP1 have been reported in cancer cells, suggesting AQP1 might be a direct HIF target. Thus, we wanted to determine whether either HIF‐1 or HIF‐2 regulates AQP1 in PASMCs. DMOG, which inhibits HIF protein degradation, was used to mimic hypoxia. PASMCs acutely incubated with DMOG exhibited a time‐dependent increase in the levels of AQP1 protein, but not mRNA, whereas both the protein and mRNA levels of a canonical HIF target, GLUT1, were increased. Since we previously reported a link between HIFs and intracellular calcium concentration ([Ca2+]i), as well as a link between [Ca2+]iand AQP1 protein levels, we next determined whether the effects of DMOG on AQP1 were mediated by an increase in [Ca2+]i. Incubation with DMOG caused an increase in [Ca2+]iin PASMCs that was partially prevented by selectively inhibiting either HIF‐1 or HIF‐2. Both inhibitors also partially blocked the DMOG‐induced upregulation of AQP1 protein. When applied together, inhibitors of both HIFs completely blocked the effects of DMOG on [Ca2+]iand AQP1 expression. Thus, our results demonstrate that, in PASMCs, AQP1 protein can be upregulated by both HIF‐1 and HIF‐2, not as a direct target for HIF transcriptional regulation, but rather by a mechanism involving protein accumulation secondary to HIF‐dependent increases in [Ca2+]i.Support or Funding InformationHL12651418POST34030262This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Hypoxic Ventilatory Response is Blocked by AMPK Deletion in Catecholaminergic, but not Adrenergic Cells
Authors: MacMillan Sandy , Evans A. Mark 
Published: June 2021

During hypoxia, ventilatory adjustments are critical to the maintenance of adequate oxygen (O2) delivery, for example during sleep or ascent to altitude (1). We recently demonstrated that the AMP‐activated protein kinase (AMPK), a ubiquitously expressed metabolic sensor (2), protects against hypoventilation and apnea during hypoxia (3). Here, we further investigated the circuit mechanism by which AMPK deficiency impacts the hypoxic ventilatory response (HVR). Using unrestrained whole‐body plethysmography, we compared the effects on the HVR of mice with dual deletion of the AMPK‐α1/α2 catalytic subunits in all catecholaminergic (TH‐positive) cells with the HVR of mice with AMPK‐α1/α2 deletion targeted to adrenergic cells alone (Phenylethanolamine N‐methyltransferase (PNMT)‐positive). Relative to controls (AMPK‐α1/α2 floxed), mice with TH‐Cre driven AMPK deletion (TH AMPK‐α1/α2 dKO) exhibited hypoventilation, characterized by marked attenuation of minute ventilation (p<0.0001) during each minute of exposures to severe hypoxia (8% O2). By contrast, in mice with PNMT‐Cre driven AMPK deletion (PNMT AMPK‐α1/α2 dKO) the HVR was augmented rather than attenuated, although this only reached significance relative to controls (AMPK‐α1/α2 floxed and PNMT Cre) when taken as averages for the whole 10min period of exposure to severe hypoxia (p<0.001–0.0001). As one might expect given these outcomes, the HVR of PNMT AMPK‐α1/α2 dKO mice was significantly greater than that for TH AMPK‐α1/α2 dKO during each full minute of hypoxia (p<0.0001). Furthermore, the apnea‐duration index (ADI) was significantly augmented in TH AMPK‐α1/α2 dKO mice compared to controls (p<0.01–0.0001). By contrast, PNMT AMPK‐α1/α2 dKO mice exhibited a reduction in the average ADI compared to controls (p<0.05–0.01). This reduction in the ADI for PNMT AMPK‐α1/α2 dKO mice was primarily due to a lower number of apneas during the first 3 to 4 minutes of hypoxic exposure, the ADI being comparable to controls between 4 and 10 min. Accordingly, the ADI of PNMT AMPK‐α1/α2 dKO was attenuated at each time point throughout the 10min exposure to hypoxia when compared to TH AMPK‐α1/α2 dKO mice (p<0.0001). In conclusion, we have uncovered a split in the AMPK‐dependent regulation of the catecholaminergic respiratory network during hypoxia, where the HVR is promoted by AMPK‐dependent modulation of noradrenergic inputs, but opposed by AMPK‐dependent modulation of adrenergic inputs. AMPK may thus protect against hypoventilation and apnea through noradrenergic signaling, and might aid restoration of normal CO2 levels during hypoxic hyperventilation through adrenergic signaling (4).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Activation of Lysine Demethylases (KDM's) by Intermittent Hypoxia
Authors: Nanduri Jayasri , Wang Ning , Semenza Gregg L , Prabhakar Nanduri R 
Published: June 2021

We previously reported that intermittent hypoxia (IH), a hallmark of sleep apnea, increases reactive oxygen species (ROS) in the central and peripheral nervous system. IH‐induced increase in ROS abundance was in part due to hypoxia‐inducible factor (HIF)‐1 dependent transcriptional up regulation of NADPH oxidase (Nox)‐2 and 4. Emerging evidence suggests that lysine demethylases (KDM's) acting as co‐activators contribute to HIF‐1‐dependent transcriptional activation. The aim of the present study is to assess whether KDM proteins contribute to IH‐evoked Nox4 transcriptional activation by HIF‐1. Experiments were performed on rat pheochromocytoma (PC12) cells treated with alternating cycles of 1.5% O2 for 30 sec followed by 20% O2 for 5 min. Protein abundance and activities of KDM2A, KDM4A, 4B, 4C and KDM6B in nuclear extracts were analyzed by immunoblot and colorimetric assays, respectively. Cells treated with 60 cycles of IH (IH60) showed increased protein abundance and activity of KDM6B. Co‐immunoprecipitation assays showed that KDM6B interacts with HIF‐1α and blockade of KDM6B with silencing RNA prevented Nox4 transcriptional activation by HIF‐1. These findings demonstrate that KDM6B functions as a coactivator of HIF‐1 mediated transactivation of Nox4 by IH.Support or Funding InformationSupported by NIH‐HL‐90554.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.