1
|
Bernardini A, Wolf A, Brockmeier U, Riffkin H, Metzen E, Acker-Palmer A, Fandrey J, Acker H. Carotid body type I cells engage flavoprotein and Pin1 for oxygen sensing. Am J Physiol Cell Physiol 2020; 318:C719-C731. [PMID: 31967857 DOI: 10.1152/ajpcell.00320.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carotid body (CB) type I cells sense the blood Po2 and generate a nervous signal for stimulating ventilation and circulation when blood oxygen levels decline. Three oxygen-sensing enzyme complexes may be used for this purpose: 1) mitochondrial electron transport chain metabolism, 2) heme oxygenase 2 (HO-2)-generating CO, and/or 3) an NAD(P)H oxidase (NOX). We hypothesize that intracellular redox changes are the link between the sensor and nervous signals. To test this hypothesis type I cell autofluorescence of flavoproteins (Fp) and NAD(P)H within the mouse CB ex vivo was recorded as Fp/(Fp+NAD(P)H) redox ratio. CB type I cell redox ratio transiently declined with the onset of hypoxia. Upon reoxygenation, CB type I cells showed a significantly increased redox ratio. As a control organ, the non-oxygen-sensing sympathetic superior cervical ganglion (SCG) showed a continuously reduced redox ratio upon hypoxia. CN-, diphenyleneiodonium, or reactive oxygen species influenced chemoreceptor discharge (CND) with subsequent loss of O2 sensitivity and inhibited hypoxic Fp reduction only in the CB but not in SCG Fp, indicating a specific role of Fp in the oxygen-sensing process. Hypoxia-induced changes in CB type I cell redox ratio affected peptidyl prolyl isomerase Pin1, which is believed to colocalize with the NADPH oxidase subunit p47phox in the cell membrane to trigger the opening of potassium channels. We postulate that hypoxia-induced changes in the Fp-mediated redox ratio of the CB regulate the Pin1/p47phox tandem to alter type I cell potassium channels and therewith CND.
Collapse
Affiliation(s)
- André Bernardini
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Alexandra Wolf
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Ulf Brockmeier
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Helena Riffkin
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Eric Metzen
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Amparo Acker-Palmer
- Institute for Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Joachim Fandrey
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Helmut Acker
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| |
Collapse
|
2
|
Takahashi T, Osanai S, Nakano H, Ohsaki Y, Kikuchi K. Doxapram stimulates the carotid body via a different mechanism than hypoxic chemotransduction. Respir Physiol Neurobiol 2005; 147:1-9. [PMID: 15848118 DOI: 10.1016/j.resp.2005.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 12/29/2004] [Accepted: 01/12/2005] [Indexed: 11/25/2022]
Abstract
To determine if doxapram stimulates the carotid body through the same mechanism as hypoxia, we compared the effects of doxapram and hypoxia on isolated-perfused carotid bodies in rabbits. Doxapram stimulated the carotid body in a dose-dependent manner. In Ca(2+)-free solution, neither doxapram nor hypoxia stimulated the carotid body. Although, doxapram had an additive effect on the carotid body chemosensory response to hypercapnia, a synergistic effect was not observed. Also, we investigated the various K(+) channel activators on the response to doxapram and hypoxia: pinacidil and levcromakalim as ATP-sensitive K(+) channel activators; NS-1619 as a Ca(2+)-sensitive K(+) channel activator; and halothane as a TASK-like background K(+) channel activator. The hypoxic response was partially reduced by halothane only, while pinacidil, levcromakalim and NS-1619 had no effect. Interestingly, the effect of doxapram was partially inhibited by NS-1619. Neither pinacidil nor levcromakalim affected the stimulatory effect of doxapram. We conclude that doxapram stimulates the carotid body via a different mechanism than hypoxic chemotransduction.
Collapse
Affiliation(s)
- Toru Takahashi
- First Department of Medicine, Asahikawa Medical College, 2-1-1-1 Midorigaoka Higash, Asahikawa 078-8510, Japan.
| | | | | | | | | |
Collapse
|
3
|
Lahiri S, Ehleben W, Acker H. Chemoreceptor discharges and cytochrome redox changes of the rat carotid body: role of heme ligands. Proc Natl Acad Sci U S A 1999; 96:9427-32. [PMID: 10430959 PMCID: PMC17799 DOI: 10.1073/pnas.96.16.9427] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In superfused in vitro rat carotid body, we recorded chemoreceptor discharges and the redox state of cytochromes simultaneously to identify the primary oxygen-sensing protein controlling transmitter release and electrical activity of the carotid sinus nerve. These parameters were tested under the influence of heme ligands such as oxygen, cyanide, 4-(2-aminoethyl)-benzenesulfonyl fluoride, and CO. During stimulation, there was an initial increase in discharge frequency followed by a decline or suppression of activity. Photometric changes lagged and were maintained as nerve activity decreased. Reducing mitochondrial cytochromes by cyanide or prolonged severe hypoxia, suppressed the chemoreceptor discharge. 4-(2-Aminoethyl)-benzenesulfonyl fluoride, a specific inhibitor of the phagocytic cytochrome b(558), also silenced the chemoreceptors after an initial excitation. CO increased the chemoreceptor discharge under normoxia, an effect inhibited by light, when the cytochromes were not reduced. When the discharges were depressed by severe hypoxia, exposure to light excited the chemoreceptors and the cytochromes were reduced. The rapidity of the chemosensory responses to light and lack of effect on dopamine release from type I cells led us to hypothesize that carotid body type I cells and the apposed nerve endings use different mechanisms for oxygen sensing: the nerve endings generate action potentials in association with membrane heme proteins whereas cytosolic heme proteins signal the redox state, releasing modulators or transmitters from type I cells.
Collapse
Affiliation(s)
- S Lahiri
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085, USA
| | | | | |
Collapse
|
4
|
Lahiri S, Acker H. Redox-dependent binding of CO to heme protein controls P(O2)-sensitive chemoreceptor discharge of the rat carotid body. RESPIRATION PHYSIOLOGY 1999; 115:169-77. [PMID: 10385031 DOI: 10.1016/s0034-5687(99)00014-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Simultaneous recordings of chemoreceptor discharge and redox state of cytochromes have been carried out on the rat carotid body in vitro under the influence of carbon monoxide (CO) in order to identify the primary oxygen sensor protein controlling transmitter release and electrical activity. CO excites in a photolabile manner chemoreceptor discharge under normoxic conditions and inhibits under hypoxic conditions probably by binding to heme proteins. We hypothesize that type I cells and adjacent nerve endings of the carotid body tissue have a different apparatus with oxygen sensing heme proteins to cooperate for the generation of peripheral chemoreceptor response. Transmitter release from type I cells might be established in a redox dependent manner whereas membrane potential of nerve endings might be controlled by a heme coupled to ion channels.
Collapse
Affiliation(s)
- S Lahiri
- Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085, USA
| | | |
Collapse
|
5
|
Goldwasser E, Alibali P, Gardner A. Differential inhibition by iodonium compounds of induced erythropoietin expression. J Biol Chem 1995; 270:2628-9. [PMID: 7852328 DOI: 10.1074/jbc.270.6.2628] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Diphenylene iodonium chloride suppresses the cobaltous chloride-induced expression of erythropoietin by Hep3B cells to about 50% at a concentration of 30 nM. At that concentration, it has no effect on the response to low oxygen. The related compound iodonium diphenyl chloride acts similarly but is a much less effective inhibitor. If, as reported, diphenylene iodonium chloride is a specific inhibitor of cytochrome b, it follows that the response to CoCl2 is dependent on that enzyme but the response to hypoxia is not.
Collapse
Affiliation(s)
- E Goldwasser
- Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637
| | | | | |
Collapse
|
6
|
Lahiri S, Wilson DF, Iturriaga R, Rumsey WL. Microvascular PO2 regulation and chemoreception in the cat carotid body. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 345:129-35. [PMID: 8079698 DOI: 10.1007/978-1-4615-2468-7_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- S Lahiri
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia 19104
| | | | | | | |
Collapse
|
7
|
Delpiano MA. Evidence for glucose uptake in the rabbit carotid body. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1993; 337:111-6. [PMID: 8109391 DOI: 10.1007/978-1-4615-2966-8_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- M A Delpiano
- Max-Planck-Institut für Systemphysiologie, Dortmund, Germany
| |
Collapse
|
8
|
Di Giulio C, Mokashi A, Huang WX, Morelli L, Data PG. Effects of inorganic calcium channel blockers on carotid chemosensory responses in the cat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1993; 337:117-21. [PMID: 8109392 DOI: 10.1007/978-1-4615-2966-8_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- C Di Giulio
- Department of Physiology, School of Medicine, Univ. of Pennsylvania, Philadelphia 19104-6085
| | | | | | | | | |
Collapse
|
9
|
Acker H, Bölling B, Delpiano MA, Dufau E, Görlach A, Holtermann G. The meaning of H2O2 generation in carotid body cells for PO2 chemoreception. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1992; 41:41-51. [PMID: 1491115 DOI: 10.1016/0165-1838(92)90125-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The rat carotid body is able to generate H2O2 in type-I cells with the aid of an electron-transferring chain with cytochrome b as the major component as it can be detected by spectrophotometry as well as confocal laser-microscopy. This cytochrome b is reducible by hypoxia, but not by cyanide, indicating that it does not participate in the energy production by the respiratory chain. The carotid body possesses a glutathione peroxidase (GPO) which scavenges H2O2 and other organic hydroperoxides. The nervous chemoreceptor discharge can be inhibited by external application of hydroperoxides with a similar half maximal value (60-80 microM) as used to stimulate GPO. A hypothetical signal chain is described which suggests the involvement of cytochrome b as an O2 sensor in PO2 chemoreception of the carotid body and the degradation of H2O2 by glutathione to control the K(+)-conductivity of carotid body cells.
Collapse
Affiliation(s)
- H Acker
- Max-Planck-Institut für Sytemphysiologie, Dortmund, FRG
| | | | | | | | | | | |
Collapse
|
10
|
Abstract
The cyclic AMP content of cat carotid bodies in vitro measured with a radioimmunoassay under control conditions (PO2: 230 torr) was 0.79 +/- 0.10 pmol/carotid body (n = 10). Lowering medium PO2 to 20 torr for 2 min significantly increased cyclic AMP content to 1.13 +/- 0.14 pmol/carotid body (n = 10). This increase was inhibited neither by propranolol (34 microM) nor by propranolol plus haloperidol (27 microM). Inhibition of the cyclic nucleotide phosphodiesterase with 1-methyl-3-isobutylxanthine (0.8 mM) provoked a fast and large increase in cyclic AMP during both control and hypoxic conditions. The cyclic AMP increase induced by hypoxia was still observed when extracellular Ca2+ was absent. Inhibition of the adenylate cyclase by N-(cis-2-phenylcyclopentyl)azacyclotridecan-2-imine hydrochloride (MDL 12330A; 20-1,000 microM) under zero-Ca2+ conditions irreversibly inhibited the cyclic AMP increase produced by hypoxia. Similarly, inhibition of the Ca2(+)-calmodulin complex by trifluoperazine (0.2 mM) or calmidazolium (R 24571; 50-200 microM) prevented the cyclic AMP response. These results suggest that cyclic AMP may be involved in the PO2-sensing mechanism of the carotid body. Hypoxia appears to activate adenylate cyclase directly and independent of any hormone-receptor interactions.
Collapse
Affiliation(s)
- M A Delpiano
- Max-Planck-Institut für Systemphysiologie, Dortmund, F.R.G
| | | |
Collapse
|
11
|
Cross AR, Henderson L, Jones OT, Delpiano MA, Hentschel J, Acker H. Involvement of an NAD(P)H oxidase as a pO2 sensor protein in the rat carotid body. Biochem J 1990; 272:743-7. [PMID: 2268299 PMCID: PMC1149771 DOI: 10.1042/bj2720743] [Citation(s) in RCA: 178] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The rat carotid body tissue reveals a photometrically measurable haem signal with absorbance maxima at 560 nm, 518 nm and 425 nm, suggesting the presence of a b-type cytochrome; this was confirmed by pyridine haemochrome and CO spectra. The quantity of cytochrome b was estimated to be 310 pmol.mg of protein-1. This haem is capable of H2O2 formation, which can be inhibited by 10 microM-diphenyliodonium (DPI). The hypoxia-induced increase in nervous chemoreceptor discharge and the reduction of FAD and NAD(P)+ were also inhibited by DPI (10 microM). These results suggest that an oxidase such as the NAD(P)H oxidase of neutrophils may act as a pO2 sensor protein in the rat carotid body, probably inducing the pO2 chemoreceptor process by H2O2 formation.
Collapse
Affiliation(s)
- A R Cross
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
| | | | | | | | | | | |
Collapse
|
12
|
Acker H, Dufau E, Huber J, Sylvester D. Indications to an NADPH oxidase as a possible pO2 sensor in the rat carotid body. FEBS Lett 1989; 256:75-8. [PMID: 2806553 DOI: 10.1016/0014-5793(89)81721-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The rat carotid body superfused with low pO2 exhibited an optical absorbance spectrum which resembles the reduced spectrum of the NADPH oxidase in neutrophils. Diphenylene iodonium (DPI) as a specific inhibitor of the oxidase attenuated the reduced absorbance spectrum in the carotid body. Also absorbance bleaching by low doses of cyanide (50 and 100 microM) was inhibited by DPI, whereas higher doses of cyanide (300 microM) caused an absorbance spectrum typical for reduced cytochromes. It is concluded that an NADPH oxidase acts as a pO2 sensor in the carotid body with low affinity for oxygen and high affinity for cyanide.
Collapse
Affiliation(s)
- H Acker
- Max-Planck-Institut für Systemphysiologie, Dortmund 1, FRG
| | | | | | | |
Collapse
|
13
|
Hescheler J, Delpiano MA, Acker H, Pietruschka F. Ionic currents on type-I cells of the rabbit carotid body measured by voltage-clamp experiments and the effect of hypoxia. Brain Res 1989; 486:79-88. [PMID: 2720436 DOI: 10.1016/0006-8993(89)91280-8] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Type-I cells (from rabbit embryos) in primary culture were studied in voltage-clamp experiments using the whole cell arrangement of the patch-clamp technique. With a pipette solution containing 130 mM K+ and 3 mM Mg-ATP, large outward currents were obtained positive to a threshold of about -30 mV by clamping cells from -50 mV to different test pulses (-80 to 50 mV). Negative to -30 mV, the slope conductance was low (outward rectification). The outward currents were blocked by external Cs+ (5 mM) and partially blocked by TEA (5 mM) and Co2+ (1 mM). The initial part of the outward currents during depolarizing voltage pulses exhibited a transient Ca2+ inward component partially superimposed to a Ca2+-dependent outward current. Inward currents were further characterized by replacing K+ with Cs+ in the intra- and extracellular solution in order to minimize the outward component and by using 1.8 mM Ca2+, 10.8 mM Ca2+ or 10.8 mM Ba2+ as charge carrier. Slow-inactivating inward currents were recorded at test potentials ranging from -50 to 40 mV (holding potential -80 mV). The maximal amplitude, measured at 10 mV in the U-shaped I-V curve, amounted to 247 +/- 103 pA (n = 3). This inward current was insensitive to 3 microM TTX, but blocked by 1 mM Co2+ and partially reduced by 10 microM D600 and 3 microM PN 200-100. In contrast to outward currents, the inward currents exhibited a 'run-down' within about 10 min. Lowering the pO2 from the control of 150 Torr (air-gassed medium) to 28 Torr had no apparent effect on inward currents, but depressed reversibly outward currents by 28%. In conclusion, it is suggested that type-I cells possess voltage-activated K+ and Ca2+ channels which might be essential for chemoreception in the carotid body.
Collapse
Affiliation(s)
- J Hescheler
- Max-Planck-Institut für Systemphysiologie, Dortmund, F.R.G
| | | | | | | |
Collapse
|