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Zhou W, Hou Y, Yu T, Wang T, Ding Y, Nie H. Submersion and hypoxia inhibit alveolar epithelial Na + transport through ERK/NF-κB signaling pathway. Respir Res 2023; 24:117. [PMID: 37095538 PMCID: PMC10127099 DOI: 10.1186/s12931-023-02428-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 04/19/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND Hypoxia is associated with many respiratory diseases, partly due to the accumulation of edema fluid and mucus on the surface of alveolar epithelial cell (AEC), which forms oxygen delivery barriers and is responsible for the disruption of ion transport. Epithelial sodium channel (ENaC) on the apical side of AEC plays a crucial role to maintain the electrochemical gradient of Na+ and water reabsorption, thus becomes the key point for edema fluid removal under hypoxia. Here we sought to explore the effects of hypoxia on ENaC expression and the further mechanism related, which may provide a possible treatment strategy in edema related pulmonary diseases. METHODS Excess volume of culture medium was added on the surface of AEC to simulate the hypoxic environment of alveoli in the state of pulmonary edema, supported by the evidence of increased hypoxia-inducible factor-1 expression. The protein/mRNA expressions of ENaC were detected, and extracellular signal-regulated kinase (ERK)/nuclear factor κB (NF-κB) inhibitor was applied to explore the detailed mechanism about the effects of hypoxia on epithelial ion transport in AEC. Meanwhile, mice were placed in chambers with normoxic or hypoxic (8%) condition for 24 h, respectively. The effects of hypoxia and NF-κB were assessed through alveolar fluid clearance and ENaC function by Ussing chamber assay. RESULTS Hypoxia (submersion culture mode) induced the reduction of protein/mRNA expression of ENaC, whereas increased the activation of ERK/NF-κB signaling pathway in parallel experiments using human A549 and mouse alveolar type 2 cells, respectively. Moreover, the inhibition of ERK (PD98059, 10 µM) alleviated the phosphorylation of IκB and p65, implying NF-κB as a downstream pathway involved with ERK regulation. Intriguingly, the expression of α-ENaC could be reversed by either ERK or NF-κB inhibitor (QNZ, 100 nM) under hypoxia. The alleviation of pulmonary edema was evidenced by the administration of NF-κB inhibitor, and enhancement of ENaC function was supported by recording amiloride-sensitive short-circuit currents. CONCLUSIONS The expression of ENaC was downregulated under hypoxia induced by submersion culture, which may be mediated by ERK/NF-κB signaling pathway.
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Affiliation(s)
- Wei Zhou
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Yapeng Hou
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Tong Yu
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Tingyu Wang
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Yan Ding
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Hongguang Nie
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China.
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Zhou W, Yu T, Hua Y, Hou Y, Ding Y, Nie H. Effects of Hypoxia on Respiratory Diseases: Perspective View of Epithelial Ion Transport. Am J Physiol Lung Cell Mol Physiol 2022; 323:L240-L250. [PMID: 35819839 DOI: 10.1152/ajplung.00065.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The balance of gas exchange and lung ventilation is essential for the maintenance of body homeostasis. There are many ion channels and transporters in respiratory epithelial cells, including epithelial sodium channel, Na,K-ATPase, cystic fibrosis transmembrane conductance regulator, and some transporters. These ion channels/transporters maintain the capacity of liquid layer on the surface of respiratory epithelial cells, and provide an immune barrier for the respiratory system to clear off foreign pathogens. However, in some harmful external environment and/or pathological conditions, the respiratory epithelium is prone to hypoxia, which would destroy the ion transport function of the epithelium and unbalance the homeostasis of internal environment, triggering a series of pathological reactions. Many respiratory diseases associated with hypoxia manifest an increased expression of hypoxia-inducible factor-1, which mediates the integrity of the epithelial barrier and affects epithelial ion transport function. It is important to study the relationship between hypoxia and ion transport function, whereas the mechanism of hypoxia-induced ion transport dysfunction in respiratory diseases is not clear. This review focuses on the relationship of hypoxia and respiratory diseases, as well as dysfunction of ion transport and tight junctions in respiratory epithelial cells under hypoxia.
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Affiliation(s)
- Wei Zhou
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Tong Yu
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Yu Hua
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Yapeng Hou
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Yan Ding
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Hongguang Nie
- Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China
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3
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Prospective Application of Ferroptosis in Hypoxic Cells for Tumor Radiotherapy. Antioxidants (Basel) 2022; 11:antiox11050921. [PMID: 35624785 PMCID: PMC9137794 DOI: 10.3390/antiox11050921] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/26/2022] [Accepted: 05/05/2022] [Indexed: 02/04/2023] Open
Abstract
Radiation therapy plays an increasingly important role in cancer treatment. It can inhibit the progression of various cancers through radiation-induced DNA breakage and reactive oxygen species (ROS) overload. Unfortunately, solid tumors, such as breast and lung cancer, often develop a hypoxic microenvironment due to insufficient blood supply and rapid tumor proliferation, thereby affecting the effectiveness of radiation therapy. Restraining hypoxia and improving the curative effect of radiotherapy have become difficult problems. Ferroptosis is a new type of cell death caused by lipid peroxidation due to iron metabolism disorders and ROS accumulation. It plays an important role in both hypoxia and radiotherapy and can enhance the radiosensitivity of hypoxic tumor cells by amplifying oxidative stress or inhibiting antioxidant regulation. In this review, we summarize the internal relationship and related mechanisms between ferroptosis and hypoxia, thus exploring the possibility of inducing ferroptosis to improve the prognosis of hypoxic tumors.
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Wu G, Li C, Tao J, Liu Z, Li X, Zang Z, Fu C, Wei J, Yang Y, Zhu Q, Zhang JQ, Shen M, Liu H. FSH mediates estradiol synthesis in hypoxic granulosa cells by activating glycolytic metabolism through the HIF-1α-AMPK-GLUT1 signaling pathway. J Biol Chem 2022; 298:101830. [PMID: 35300979 PMCID: PMC9036125 DOI: 10.1016/j.jbc.2022.101830] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/31/2022] Open
Abstract
Owing to the avascular environment within ovarian follicles, granulosa cells (GCs) are believed to live in a hypoxic niche. Follicle-stimulating hormone (FSH)-mediated steroidogenesis is crucial for normal growth and maturation of ovarian follicles, but it remains unclear how FSH stimulates estradiol (E2) synthesis under hypoxic conditions. Here, we aimed to explore whether FSH affects the ATP production required for estrogen synthesis from the perspective of glucose metabolism. It was observed that the levels of both E2 and HIF-1α were markedly increased in a dose-dependent manner in mouse ovarian GCs after the injection of FSH in vivo, indicating that hypoxia/HIF-1α may be relevant to FSH-induced E2 synthesis. By treating hypoxic GCs with FSH in vitro, we further revealed that the activation of the AMP-activated protein kinase (AMPK)–GLUT1 pathway, which in turn stimulates ATP generation, may be essential for FSH-mediated E2 production during hypoxia. In contrast, inhibition of AMPK or GLUT1 with siRNAs/antagonist both repressed glycolysis, ATP production, and E2 synthesis despite FSH treatment. Moreover, blocking HIF-1α activity using siRNAs/PX-478 suppressed AMPK activation, GLUT1 expression, and E2 levels in FSH-treated GCs. Finally, the in vitro findings were verified in vivo, which showed markedly increased AMPK activity, GLUT1 expression, glycolytic flux, ATP levels, and E2 concentrations in ovarian GCs following FSH injection. Taken together, these findings uncovered a novel mechanism for FSH-regulating E2 synthesis in hypoxic GCs by activating glycolytic metabolism through the HIF-1α–AMPK–GLUT1 pathway.
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Affiliation(s)
- Gang Wu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Chengyu Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Jingli Tao
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Zhaojun Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xiaoxuan Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Ziyu Zang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Chen Fu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Jiayuan Wei
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Yaxing Yang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Qian Zhu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Jia-Qing Zhang
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Ming Shen
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
| | - Honglin Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
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AMPK-mTOR Signaling and Cellular Adaptations in Hypoxia. Int J Mol Sci 2021; 22:ijms22189765. [PMID: 34575924 PMCID: PMC8465282 DOI: 10.3390/ijms22189765] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 12/14/2022] Open
Abstract
Cellular energy is primarily provided by the oxidative degradation of nutrients coupled with mitochondrial respiration, in which oxygen participates in the mitochondrial electron transport chain to enable electron flow through the chain complex (I-IV), leading to ATP production. Therefore, oxygen supply is an indispensable chapter in intracellular bioenergetics. In mammals, oxygen is delivered by the bloodstream. Accordingly, the decrease in cellular oxygen level (hypoxia) is accompanied by nutrient starvation, thereby integrating hypoxic signaling and nutrient signaling at the cellular level. Importantly, hypoxia profoundly affects cellular metabolism and many relevant physiological reactions induce cellular adaptations of hypoxia-inducible gene expression, metabolism, reactive oxygen species, and autophagy. Here, we introduce the current knowledge of hypoxia signaling with two-well known cellular energy and nutrient sensing pathways, AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1). Additionally, the molecular crosstalk between hypoxic signaling and AMPK/mTOR pathways in various hypoxic cellular adaptions is discussed.
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6
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Liu L, Liu X, Liu M, Xie D, Yan H. Proline hydroxylase domain-containing enzymes regulate calcium levels in cardiomyocytes by TRPA1 ion channel. Exp Cell Res 2021; 407:112777. [PMID: 34389294 DOI: 10.1016/j.yexcr.2021.112777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 07/01/2021] [Accepted: 08/07/2021] [Indexed: 11/15/2022]
Abstract
The proline hydroxylase domain-containing enzymes (PHDs) acts as cellular oxygen sensors, inducing a series of responses to hypoxia, especially during the regulation of metabolism and energy homeostasis. The increase of Ca2+ in cardiomyocytes, induced by the opening of PHD signaling pathway, is the key initiation signal necessary for the PHD-mediated regulation of the energy metabolism pathway, but the underlying molecular mechanism remains incompletely understood. This study used PHD inhibitors (PHIs) and PHD2-specific RNA interference (PHD2shRNA) to inhibit PHD signals in cardiomyocytes to explore whether transient receptor potential ankyrin 1 (TRPA1) is involved in the regulation of calcium ion influx in the PHD activation pathway associated with to AMP-activated protein kinase (AMPK). The Fluo-3AM probe was used to measure changes in free intracellular calcium ion concentrations, and western blot analysis was used to detect the levels of phosphorylated (P)-AMPK, TRPA1, and P-Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) levels. The PHI-mediated inhibition of PHD resulted in an increase in free Ca2+ fluorescence in cardiomyocytes, which activated AMPK, TRPA1, and CaMKⅡ. The TRPA1 inhibitor HC030031, the CaMKII inhibitor KN93, and a ryanodine inhibitor (Ryanodine) were all able to inhibit the PHI-induced increase in intracellular Ca2+ and AMPK activation. Both PHIs and PHD2shRNA were able to effectively activate CaMKII and TRPA1. However, an inositol 1,4,5-triphosphate receptor (IP3R) inhibitor and the protein kinase A (PKA) inhibitor H89 did not significantly inhibit the PHI-induced increase in intracellular Ca2+ and AMPK activation. These results indicated that PHD might activate the CaMKⅡ pathway through the TRPA1 ion channel, inducing the release of calcium from the sarcoplasmic reticulum through ryanodine receptor 2 (RyR2), activating AMPK to initiate the protective effects of hypoxia in cardiomyocytes.
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Affiliation(s)
- Lan Liu
- Department of Plastic and Burn Surgery, Affiliated Hospital of Southwest Medical University, National Key Clinical Construction Specialty, Wound Repair and Regeneration Laboratory, Luzhou, Sichuan Province, 646000, China
| | - Xingke Liu
- Department of Plastic and Burn Surgery, Affiliated Hospital of Southwest Medical University, National Key Clinical Construction Specialty, Wound Repair and Regeneration Laboratory, Luzhou, Sichuan Province, 646000, China
| | - Mengchang Liu
- Department of Plastic and Burn Surgery, Affiliated Hospital of Southwest Medical University, National Key Clinical Construction Specialty, Wound Repair and Regeneration Laboratory, Luzhou, Sichuan Province, 646000, China
| | - Defu Xie
- Department of Plastic and Burn Surgery, Affiliated Hospital of Southwest Medical University, National Key Clinical Construction Specialty, Wound Repair and Regeneration Laboratory, Luzhou, Sichuan Province, 646000, China
| | - Hong Yan
- Department of Plastic and Burn Surgery, Affiliated Hospital of Southwest Medical University, National Key Clinical Construction Specialty, Wound Repair and Regeneration Laboratory, Luzhou, Sichuan Province, 646000, China.
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7
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Salem AA, Ismail AFM. Protective impact of Spirulina platensis against γ-irradiation and thioacetamide-induced nephrotoxicity in rats mediated by regulation of micro-RNA 1 and micro-RNA 146a. Toxicol Res (Camb) 2021; 10:453-466. [PMID: 34141159 DOI: 10.1093/toxres/tfab037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/02/2021] [Accepted: 03/25/2021] [Indexed: 12/25/2022] Open
Abstract
Chronic kidney disease develops popular and medical health problems, especially in developing countries. The objective of this study is to investigate the protective mechanism of Spirulina platensis against γ-irradiation (R) and/or thioacetamide (TAA)-induced nephrotoxicity in rats. Rats intoxicated with R or TAA showed alterations in kidney function markers (urea, creatinine, albumin, and total protein contents), oxidative stress markers (malondialdehyde, reduced glutathione), antioxidant enzymes (superoxide dismutase, catalase), and several inflammatory markers (including, the high-sensitivity C-reactive protein, hypoxia-inducible factor-1 alpha, tumor necrosis factor-alpha, interferon-gamma, some interleukins, and nuclear factor-kappa B). Rats also acquired apoptosis, evinced by high caspase-3 efficacy. This nephrotoxicity mediated by upregulation of the messenger RNA (mRNA) gene expression of the autophagy markers: Beclin-1, microtubule-associated protein LC3, p62 binding protein, immunoglobulin G receptor Fcγ receptor (FcγR), micro-RNA-1 (miR-1), protein expression of phospho-adenosine monophosphate-activated protein kinase, and phospho-mammalian target of rapamycin, along with downregulation of miR-146a mRNA gene expression and alteration of calcium and iron levels. The combined treatment R/TAA enhanced the observed oxidative stress, inflammation, apoptosis, and autophagy that mediated by higher upregulation of miR-1 and downregulation of miR-146a mRNA gene expression. Spirulina platensis administration exhibited a nephroprotective impact on R, TAA, and R/TAA toxicities via regulating miR-1 and miR-146a mRNA gene expression that monitored adenosine monophosphate-activated protein kinase/mammalian target of rapamycin signaling.
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Affiliation(s)
- Asmaa A Salem
- Regional Center for Food and Feed (RCFF), Agricultural Research Center, Giza 12619, Egypt
| | - Amel F M Ismail
- Drug Radiation Research Department, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority (EAEA), Ahmed El-Zomor St. 3, El-Zohoor Dist., Nasr City, 11787 Cairo, Egypt
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8
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The role of AMPK in regulation of Na +,K +-ATPase in skeletal muscle: does the gauge always plug the sink? J Muscle Res Cell Motil 2021; 42:77-97. [PMID: 33398789 DOI: 10.1007/s10974-020-09594-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022]
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy gauge and a major regulator of cellular energy homeostasis. Once activated, AMPK stimulates nutrient uptake and the ATP-producing catabolic pathways, while it suppresses the ATP-consuming anabolic pathways, thus helping to maintain the cellular energy balance under energy-deprived conditions. As much as ~ 20-25% of the whole-body ATP consumption occurs due to a reaction catalysed by Na+,K+-ATPase (NKA). Being the single most important sink of energy, NKA might seem to be an essential target of the AMPK-mediated energy saving measures, yet NKA is vital for maintenance of transmembrane Na+ and K+ gradients, water homeostasis, cellular excitability, and the Na+-coupled transport of nutrients and ions. Consistent with the model that AMPK regulates ATP consumption by NKA, activation of AMPK in the lung alveolar cells stimulates endocytosis of NKA, thus suppressing the transepithelial ion transport and the absorption of the alveolar fluid. In skeletal muscles, contractions activate NKA, which opposes a rundown of transmembrane ion gradients, as well as AMPK, which plays an important role in adaptations to exercise. Inhibition of NKA in contracting skeletal muscle accentuates perturbations in ion concentrations and accelerates development of fatigue. However, different models suggest that AMPK does not inhibit or even stimulates NKA in skeletal muscle, which appears to contradict the idea that AMPK maintains the cellular energy balance by always suppressing ATP-consuming processes. In this short review, we examine the role of AMPK in regulation of NKA in skeletal muscle and discuss the apparent paradox of AMPK-stimulated ATP consumption.
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Woodall M, Jacob J, Kalsi KK, Schroeder V, Davis E, Kenyon B, Khan I, Garnett JP, Tarran R, Baines DL. E-cigarette constituents propylene glycol and vegetable glycerin decrease glucose uptake and its metabolism in airway epithelial cells in vitro. Am J Physiol Lung Cell Mol Physiol 2020; 319:L957-L967. [PMID: 32996783 PMCID: PMC7792687 DOI: 10.1152/ajplung.00123.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 02/07/2023] Open
Abstract
Electronic nicotine delivery systems, or e-cigarettes, utilize a liquid solution that normally contains propylene glycol (PG) and vegetable glycerin (VG) to generate vapor and act as a carrier for nicotine and flavorings. Evidence indicated these "carriers" reduced growth and survival of epithelial cells including those of the airway. We hypothesized that 3% PG or PG mixed with VG (3% PG/VG, 55:45) inhibited glucose uptake in human airway epithelial cells as a first step to reducing airway cell survival. Exposure of H441 or human bronchiolar epithelial cells (HBECs) to PG and PG/VG (30-60 min) inhibited glucose uptake and mitochondrial ATP synthesis. PG/VG inhibited glycolysis. PG/VG and mannitol reduced cell volume and height of air-liquid interface cultures. Mannitol, but not PG/VG, increased phosphorylation of p38 MAPK. PG/VG reduced transepithelial electrical resistance, which was associated with increased transepithelial solute permeability. PG/VG decreased fluorescence recovery after photobleaching of green fluorescent protein-linked glucose transporters GLUT1 and GLUT10, indicating that glucose transport function was compromised. Puffing PG/VG vapor onto the apical surface of primary HBECs for 10 min to mimic the effect of e-cigarette smoking also reduced glucose transport. In conclusion, short-term exposure to PG/VG, key components of e-cigarettes, decreased glucose transport and metabolism in airway cells. We propose that this was a result of PG/VG reduced cell volume and membrane fluidity, with further consequences on epithelial barrier function. Taking these results together, we suggest these factors contribute to reduced defensive properties of the epithelium. We propose that repeated/chronic exposure to these agents are likely to contribute to airway damage in e-cigarette users.
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Affiliation(s)
- M. Woodall
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - J. Jacob
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - K. K. Kalsi
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - V. Schroeder
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - E. Davis
- Marsico Lung Institute and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - B. Kenyon
- Marsico Lung Institute and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - I. Khan
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
| | - J. P. Garnett
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - R. Tarran
- Marsico Lung Institute and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - D. L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, United Kingdom
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Evans AM, Hardie DG. AMPK and the Need to Breathe and Feed: What's the Matter with Oxygen? Int J Mol Sci 2020; 21:ijms21103518. [PMID: 32429235 PMCID: PMC7279029 DOI: 10.3390/ijms21103518] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022] Open
Abstract
We live and to do so we must breathe and eat, so are we a combination of what we eat and breathe? Here, we will consider this question, and the role in this respect of the AMP-activated protein kinase (AMPK). Emerging evidence suggests that AMPK facilitates central and peripheral reflexes that coordinate breathing and oxygen supply, and contributes to the central regulation of feeding and food choice. We propose, therefore, that oxygen supply to the body is aligned with not only the quantity we eat, but also nutrient-based diet selection, and that the cell-specific expression pattern of AMPK subunit isoforms is critical to appropriate system alignment in this respect. Currently available information on how oxygen supply may be aligned with feeding and food choice, or vice versa, through our motivation to breathe and select particular nutrients is sparse, fragmented and lacks any integrated understanding. By addressing this, we aim to provide the foundations for a clinical perspective that reveals untapped potential, by highlighting how aberrant cell-specific changes in the expression of AMPK subunit isoforms could give rise, in part, to known associations between metabolic disease, such as obesity and type 2 diabetes, sleep-disordered breathing, pulmonary hypertension and acute respiratory distress syndrome.
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Affiliation(s)
- A. Mark Evans
- Centre for Discovery Brain Sciences and Cardiovascular Science, Edinburgh Medical School, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
- Correspondence:
| | - D. Grahame Hardie
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK;
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11
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Dengler F. Activation of AMPK under Hypoxia: Many Roads Leading to Rome. Int J Mol Sci 2020; 21:ijms21072428. [PMID: 32244507 PMCID: PMC7177550 DOI: 10.3390/ijms21072428] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/13/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is known as a pivotal cellular energy sensor, mediating the adaptation to low energy levels by deactivating anabolic processes and activating catabolic processes in order to restore the cellular ATP supply when the cellular AMP/ATP ratio is increased. Besides this well-known role, it has also been shown to exert protective effects under hypoxia. While an insufficient supply with oxygen might easily deplete cellular energy levels, i.e., ATP concentration, manifold other mechanisms have been suggested and are heavily disputed regarding the activation of AMPK under hypoxia independently from cellular AMP concentrations. However, an activation of AMPK preceding energy depletion could induce a timely adaptation reaction preventing more serious damage. A connection between AMPK and the master regulator of hypoxic adaptation via gene transcription, hypoxia-inducible factor (HIF), has also been taken into account, orchestrating their concerted protective action. This review will summarize the current knowledge on mechanisms of AMPK activation under hypoxia and its interrelationship with HIF.
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Affiliation(s)
- Franziska Dengler
- Institute of Veterinary Physiology, University of Leipzig, D-04103 Leipzig, Germany
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12
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Chen H, Vanhoutte PM, Leung SWS. Vascular adenosine monophosphate-activated protein kinase: Enhancer, brake or both? Basic Clin Pharmacol Toxicol 2019; 127:81-91. [PMID: 31671245 DOI: 10.1111/bcpt.13357] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/24/2019] [Indexed: 12/25/2022]
Abstract
Adenosine monophosphate-activated protein kinase (AMPK), expressed/present ubiquitously in the body, contributes to metabolic regulation. In the vasculature, activation of AMPK is associated with several beneficial biological effects including enhancement of vasodilatation, reduction of oxidative stress and inhibition of inflammatory reactions. The vascular protective effects of certain anti-diabetic (metformin and sitagliptin) or lipid-lowering (simvastatin and fenofibrate) therapeutic agents, of active components of Chinese medicinal herbs (resveratrol and berberine) and of pharmacological agents (AICAR, A769662 and PT1) have been attributed to the activation of AMPK (in endothelial cells, vascular smooth muscle cells and/or perivascular adipocytes), independently of changes in the metabolic profile (eg glucose tolerance and/or plasma lipoprotein levels), leading to improved endothelium-derived nitric oxide-mediated vasodilatation and attenuated endothelium-derived cyclooxygenase-dependent vasoconstriction. By contrast, endothelial AMPK activation with pharmacological agents or by genetic modification is associated with reduced endothelium-dependent relaxations in small blood vessels and elevated systolic blood pressure. Indeed, AMPK activators inhibit endothelium-dependent hyperpolarization (EDH)-type relaxations in superior mesenteric arteries, partly by inhibiting endothelial calcium-activated potassium channel signalling. Therefore, AMPK activation is not necessarily beneficial in terms of endothelial function. The contribution of endothelial AMPK in the regulation of vascular tone, in particular in the microvasculature where EDH plays a more important role, remains to be characterized.
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Affiliation(s)
- Hui Chen
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
| | - Paul Michel Vanhoutte
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China.,State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China.,Department of Cardiovascular and Renal Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Susan Wai Sum Leung
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
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Dengler F, Gäbel G. The Fast Lane of Hypoxic Adaptation: Glucose Transport Is Modulated via A HIF-Hydroxylase-AMPK-Axis in Jejunum Epithelium. Int J Mol Sci 2019; 20:ijms20204993. [PMID: 31601024 PMCID: PMC6834319 DOI: 10.3390/ijms20204993] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/21/2022] Open
Abstract
The intestinal epithelium is able to adapt to varying blood flow and, thus, oxygen availability. Still, the adaptation fails under pathologic situations. A better understanding of the mechanisms underlying the epithelial adaptation to hypoxia could help to improve the therapeutic approach. We hypothesized that the short-term adaptation to hypoxia is mediated via AMP-activated protein kinase (AMPK) and that it is coupled to the long-term adaptation by a common regulation mechanism, the HIF-hydroxylase enzymes. Further, we hypothesized the transepithelial transport of glucose to be part of this short-term adaptation. We conducted Ussing chamber studies using isolated lagomorph jejunum epithelium and cell culture experiments with CaCo-2 cells. The epithelia and cells were incubated under 100% and 21% O2, respectively, with the panhydroxylase inhibitor dimethyloxalylglycine (DMOG) or under 1% O2. We showed an activation of AMPK under hypoxia and after incubation with DMOG by Western blot. This could be related to functional effects like an impairment of Na+-coupled glucose transport. Inhibitor studies revealed a recruitment of glucose transporter 1 under hypoxia, but not after incubation with DMOG. Summing up, we showed an influence of hydroxylase enzymes on AMPK activity and similarities between hypoxia and the effects of hydroxylase inhibition on functional changes.
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Affiliation(s)
- Franziska Dengler
- Institute of Veterinary Physiology, University of Leipzig, 04103 Leipzig, Germany.
| | - Gotthold Gäbel
- Institute of Veterinary Physiology, University of Leipzig, 04103 Leipzig, Germany.
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Krause NC, Kutsche HS, Santangelo F, DeLeon ER, Dittrich NP, Olson KR, Althaus M. Hydrogen sulfide contributes to hypoxic inhibition of airway transepithelial sodium absorption. Am J Physiol Regul Integr Comp Physiol 2016; 311:R607-17. [DOI: 10.1152/ajpregu.00177.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/13/2016] [Indexed: 01/23/2023]
Abstract
In lung epithelial cells, hypoxia decreases the expression and activity of sodium-transporting molecules, thereby reducing the rate of transepithelial sodium absorption. The mechanisms underlying the sensing of hypoxia and subsequent coupling to sodium-transporting molecules remain unclear. Hydrogen sulfide (H2S) has recently been recognized as a cellular signaling molecule whose intracellular concentrations critically depend on oxygen levels. Therefore, it was questioned whether endogenously produced H2S contributes to hypoxic inhibition of sodium transport. In electrophysiological Ussing chamber experiments, hypoxia was established by decreasing oxygen concentrations in the chambers. Hypoxia concentration dependently and reversibly decreased amiloride-sensitive sodium absorption by cultured H441 monolayers and freshly dissected porcine tracheal epithelia due to inhibition of basolateral Na+/K+-ATPase. Exogenous application of H2S by the sulfur salt Na2S mimicked the effect of hypoxia and inhibited amiloride-sensitive sodium absorption by both tissues in an oxygen-dependent manner. Hypoxia increased intracellular concentrations of H2S and decreased the concentration of polysulfides. Pretreatment with the cystathionine-γ-lyase inhibitor d/l-propargylglycine (PAG) decreased hypoxic inhibition of sodium transport by H441 monolayers, whereas inhibition of cystathionine-β-synthase (with aminooxy-acetic acid; AOAA) or 3-mercaptopyruvate sulfurtransferase (with aspartate) had no effect. Inhibition of all of these H2S-generating enzymes with a combination of AOAA, PAG, and aspartate decreased the hypoxic inhibition of sodium transport by H441 cells and pig tracheae and decreased H2S production by tracheae. These data suggest that airway epithelial cells endogenously produce H2S during hypoxia, and this contributes to hypoxic inhibition of transepithelial sodium absorption.
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Affiliation(s)
- Nicole C. Krause
- Institute for Animal Physiology, Justus-Liebig-University, Giessen, Germany; and
| | - Hanna S. Kutsche
- Institute for Animal Physiology, Justus-Liebig-University, Giessen, Germany; and
| | - Fabrizio Santangelo
- Institute for Animal Physiology, Justus-Liebig-University, Giessen, Germany; and
| | - Eric R. DeLeon
- Department of Physiology, Indiana University School of Medicine-South Bend, South Bend, Indiana
| | - Nikolaus P. Dittrich
- Institute for Animal Physiology, Justus-Liebig-University, Giessen, Germany; and
| | - Kenneth R. Olson
- Department of Physiology, Indiana University School of Medicine-South Bend, South Bend, Indiana
| | - Mike Althaus
- Institute for Animal Physiology, Justus-Liebig-University, Giessen, Germany; and
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15
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Wujak ŁA, Blume A, Baloğlu E, Wygrecka M, Wygowski J, Herold S, Mayer K, Vadász I, Besuch P, Mairbäurl H, Seeger W, Morty RE. FXYD1 negatively regulates Na(+)/K(+)-ATPase activity in lung alveolar epithelial cells. Respir Physiol Neurobiol 2015; 220:54-61. [PMID: 26410457 DOI: 10.1016/j.resp.2015.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 09/17/2015] [Accepted: 09/20/2015] [Indexed: 01/10/2023]
Abstract
Acute respiratory distress syndrome (ARDS) is clinical syndrome characterized by decreased lung fluid reabsorption, causing alveolar edema. Defective alveolar ion transport undertaken in part by the Na(+)/K(+)-ATPase underlies this compromised fluid balance, although the molecular mechanisms at play are not understood. We describe here increased expression of FXYD1, FXYD3 and FXYD5, three regulatory subunits of the Na(+)/K(+)-ATPase, in the lungs of ARDS patients. Transforming growth factor (TGF)-β, a pathogenic mediator of ARDS, drove increased FXYD1 expression in A549 human lung alveolar epithelial cells, suggesting that pathogenic TGF-β signaling altered Na(+)/K(+)-ATPase activity in affected lungs. Lentivirus-mediated delivery of FXYD1 and FXYD3 allowed for overexpression of both regulatory subunits in polarized H441 cell monolayers on an air/liquid interface. FXYD1 but not FXYD3 overexpression inhibited amphotericin B-sensitive equivalent short-circuit current in Ussing chamber studies. Thus, we speculate that FXYD1 overexpression in ARDS patient lungs may limit Na(+)/K(+)-ATPase activity, and contribute to edema persistence.
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Affiliation(s)
- Łukasz A Wujak
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany; Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany; Department of Biochemistry, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Anna Blume
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Emel Baloğlu
- Department of Sports Medicine, Medical Clinic VII, University Hospital Heidelberg, University of Heidelberg, Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Department of Medical Pharmacology, Acibadem University, İstanbul, Turkey
| | - Małgorzata Wygrecka
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany; Department of Biochemistry, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Jegor Wygowski
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Susanne Herold
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Konstantin Mayer
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - István Vadász
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Petra Besuch
- Department of Pathology, Klinikum Frankfurt (Oder) GmbH, Frankfurt (Oder), Germany
| | - Heimo Mairbäurl
- Department of Biochemistry, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Werner Seeger
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany; Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Rory E Morty
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany; Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
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16
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Agné AM, Baldin JP, Benjamin AR, Orogo-Wenn MC, Wichmann L, Olson KR, Walters DV, Althaus M. Hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting ENaC-mediated transepithelial sodium absorption. Am J Physiol Regul Integr Comp Physiol 2015; 308:R636-49. [PMID: 25632025 DOI: 10.1152/ajpregu.00489.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/19/2015] [Indexed: 01/11/2023]
Abstract
In pulmonary epithelia, β-adrenergic agonists regulate the membrane abundance of the epithelial sodium channel (ENaC) and, thereby, control the rate of transepithelial electrolyte absorption. This is a crucial regulatory mechanism for lung liquid clearance at birth and thereafter. This study investigated the influence of the gaseous signaling molecule hydrogen sulfide (H2S) on β-adrenergic agonist-regulated pulmonary sodium and liquid absorption. Application of the H2S-liberating molecule Na2S (50 μM) to the alveolar compartment of rat lungs in situ decreased baseline liquid absorption and abrogated the stimulation of liquid absorption by the β-adrenergic agonist terbutaline. There was no additional effect of Na2S over that of the ENaC inhibitor amiloride. In electrophysiological Ussing chamber experiments with native lung epithelia (Xenopus laevis), Na2S inhibited the stimulation of amiloride-sensitive current by terbutaline. β-adrenergic agonists generally increase ENaC abundance by cAMP formation and activation of PKA. Activation of this pathway by forskolin and 3-isobutyl-1-methylxanthine increased amiloride-sensitive currents in H441 pulmonary epithelial cells. This effect was inhibited by Na2S in a dose-dependent manner (5-50 μM). Na2S had no effect on cellular ATP concentration, cAMP formation, and activation of PKA. By contrast, Na2S prevented the cAMP-induced increase in ENaC activity in the apical membrane of H441 cells. H441 cells expressed the H2S-generating enzymes cystathionine-β-synthase, cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase, and they produced H2S amounts within the employed concentration range. These data demonstrate that H2S prevents the stimulation of ENaC by cAMP/PKA and, thereby, inhibits the proabsorptive effect of β-adrenergic agonists on lung liquid clearance.
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Affiliation(s)
- Alisa M Agné
- Institute of Animal Physiology, Department of Molecular Cell Physiology, Justus-Liebig University, Giessen, Germany
| | - Jan-Peter Baldin
- Institute of Animal Physiology, Department of Molecular Cell Physiology, Justus-Liebig University, Giessen, Germany
| | - Audra R Benjamin
- Division of Clinical Sciences, St. George's University of London, London, United Kingdom
| | - Maria C Orogo-Wenn
- Division of Clinical Sciences, St. George's University of London, London, United Kingdom
| | - Lukas Wichmann
- Institute of Animal Physiology, Department of Molecular Cell Physiology, Justus-Liebig University, Giessen, Germany
| | - Kenneth R Olson
- Department of Physiology, Indiana University School of Medicine-South Bend, South Bend, Indiana; and
| | - Dafydd V Walters
- Division of Clinical Sciences, St. George's University of London, London, United Kingdom
| | - Mike Althaus
- Institute of Animal Physiology, Department of Molecular Cell Physiology, Justus-Liebig University, Giessen, Germany;
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17
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Vogel ER, Britt RD, Trinidad MC, Faksh A, Martin RJ, MacFarlane PM, Pabelick CM, Prakash YS. Perinatal oxygen in the developing lung. Can J Physiol Pharmacol 2014; 93:119-27. [PMID: 25594569 DOI: 10.1139/cjpp-2014-0387] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Lung diseases, such as bronchopulmonary dysplasia (BPD), wheezing, and asthma, remain significant causes of morbidity and mortality in the pediatric population, particularly in the setting of premature birth. Pulmonary outcomes in these infants are highly influenced by perinatal exposures including prenatal inflammation, postnatal intensive care unit interventions, and environmental agents. Here, there is strong evidence that perinatal supplemental oxygen administration has significant effects on pulmonary development and health. This is of particular importance in the preterm lung, where premature exposure to room air represents a hyperoxic insult that may cause harm to a lung primed to develop in a hypoxic environment. Preterm infants are also subject to increased episodes of hypoxia, which may also result in pulmonary damage and disease. Here, we summarize the current understanding of the effects of oxygen on the developing lung and how low vs. high oxygen may predispose to pulmonary disease that may extend even into adulthood. Better understanding of the underlying mechanisms will help lead to improved care and outcomes in this vulnerable population.
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Affiliation(s)
- Elizabeth R Vogel
- a Department of Anesthesiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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18
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Erpicum P, Krzesinski JM, Jouret F. [Role of AMP-activated protein kinase in renal ischemic preconditioning]. Nephrol Ther 2013; 10:17-24. [PMID: 24387947 DOI: 10.1016/j.nephro.2013.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 08/06/2013] [Accepted: 10/15/2013] [Indexed: 12/29/2022]
Abstract
Kidney transplantation represents the best treatment of end-stage renal disease. In addition to the degree of human leukocyte antigen matching, long-term graft survival is influenced by the quality of the graft before its transplantation. Quality criteria include the level of ischemic damage caused by the transplantation per se. Renal ischemic preconditioning (IP) consists of different approaches to prevent ischemia/reperfusion (I/R) damage induced by the interruption and recovery of renal circulation, as observed during transplantation. Distinct animal models show promising results regarding the efficiency of PCI to preserve kidney structure and function in I/R conditions. Characterizing the cellular cascades involved in I/R led to the identification of putative targets of renal IP, including the adenosine monophosphate-activated protein kinase (AMPK). AMPK is a ubiquitous energy sensor, which has been implicated in the maintenance of epithelial cell polarization under energy deprivation. Among others, the anti-diabetic drug, metformin, is a potent activator of AMPK. Here, we summarize the in vitro and in vivo data about the role of AMPK in renal IP. Defining the pharmacological conditions of IP would help to improve the quality of the renal graft before its transplantation, thereby increasing its long-term survival.
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Affiliation(s)
- Pauline Erpicum
- Service de néphrologie, université de Liège CHU (ULg CHU), CHU de Liège, tour 1, 6(e) étage, avenue de l'Hôpital, 1 B-4000 Liège, Belgique
| | - Jean-Marie Krzesinski
- Service de néphrologie, université de Liège CHU (ULg CHU), CHU de Liège, tour 1, 6(e) étage, avenue de l'Hôpital, 1 B-4000 Liège, Belgique; GIGA Cardiovascular Sciences, université de Liège, tour 3, 5(e) étage, avenue de l'Hôpital, 1 B-4000 Liège, Belgique
| | - François Jouret
- Service de néphrologie, université de Liège CHU (ULg CHU), CHU de Liège, tour 1, 6(e) étage, avenue de l'Hôpital, 1 B-4000 Liège, Belgique; GIGA Cardiovascular Sciences, université de Liège, tour 3, 5(e) étage, avenue de l'Hôpital, 1 B-4000 Liège, Belgique.
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19
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Lang F, Föller M. Regulation of ion channels and transporters by AMP-activated kinase (AMPK). Channels (Austin) 2013; 8:20-8. [PMID: 24366036 DOI: 10.4161/chan.27423] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The energy-sensing AMP-activated kinase AMPK ensures survival of energy-depleted cells by stimulating ATP production and limiting ATP utilization. Both energy production and energy consumption are profoundly influenced by transport processes across the cell membane including channels, carriers and pumps. Accordingly, AMPK is a powerful regulator of transport across the cell membrane. AMPK regulates diverse K(+) channels, Na(+) channels, Ca(2+) release activated Ca(2+) channels, Cl(-) channels, gap junctional channels, glucose carriers, Na(+)/H(+)-exchanger, monocarboxylate-, phosphate-, creatine-, amino acid-, peptide- and osmolyte-transporters, Na(+)/Ca(2+)-exchanger, H(+)-ATPase and Na(+)/K(+)-ATPase. AMPK activates ubiquitin ligase Nedd4-2, which labels several plasma membrane proteins for degradation. AMPK further regulates transport proteins by inhibition of Rab GTPase activating protein (GAP) TBC1D1. It stimulates phosphatidylinositol 3-phosphate 5-kinase PIKfyve and inhibits phosphatase and tensin homolog (PTEN) via glycogen synthase kinase 3β (GSK3β). Moreover, it stabilizes F-actin as well as downregulates transcription factor NF-κB. All those cellular effects serve to regulate transport proteins.
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Affiliation(s)
- Florian Lang
- Department of Physiology; University of Tübingen; Tübingen, Germany
| | - Michael Föller
- Department of Physiology; University of Tübingen; Tübingen, Germany
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20
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Hobbs CA, Da Tan C, Tarran R. Does epithelial sodium channel hyperactivity contribute to cystic fibrosis lung disease? J Physiol 2013; 591:4377-87. [PMID: 23878362 DOI: 10.1113/jphysiol.2012.240861] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Airway epithelia absorb Na+ through the epithelial Na+ channel (ENaC) and secrete Cl- through the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. This balance maintains sufficient airway surface liquid hydration to permit efficient mucus clearance, which is needed to maintain sterility of the lung. Cystic fibrosis (CF) is a common autosomal recessive inherited disease caused by mutations in the CFTR gene that lead to the reduction or elimination of the CFTR protein. CF is a multi-organ disease that affects epithelia lining the intestines, lungs, pancreas, sweat ducts and vas deferens, among others. CF lungs are characterized by viscous, dehydrated mucus, persistent neutrophilia and chronic infections. ENaC is negatively regulated by CFTR and, in patients with CF, the absence of CFTR results in a double hit of reduced Cl-/HCO3- and H2O secretion as well as ENaC hyperactivity and increased Na+ and H2O absorption. Together, these effects are hypothesized to trigger mucus dehydration, resulting in a failure to clear mucus. Rehydrating CF mucus has become a recent clinical focus and yields important end-points for clinical trials. However, while ENaC hyperactivity in CF airways has been detected in vivo and in vitro, recent data have brought the role of ENaC in CF lung disease pathogenesis into question. This review will focus on our current understanding of the contribution of ENaC to CF pathogenesis.
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Affiliation(s)
- Carey A Hobbs
- R. Tarran: 7125 Thurston Bowles Building, UNC, Chapel Hill, NC 27599-7248, USA.
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