Cystathionine-γ-lyase (CSE) deficiency increases erythropoiesis and promotes mitochondrial electron transport via the upregulation of coproporphyrinogen III oxidase and consequent stimulation of heme biosynthesis

Katalin Modis, V-M Ramanujam, Armita Abdollahi Govar, Ernesto Lopez, Karl Anderson, Rui Wang, Csaba Szabo

Research output: Contribution to journalArticle

Abstract

Background: Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced by mammalian cells. The current study investigated the potential role of H2S in the regulation of heme biosynthesis using mice deficient in cystathionine gamma-lyase (CSE), one of the three major mammalian H2S-producing enzymes. Methods: Wild-type and global CSE−/− mice, as well as mitochondria prepared from their liver were used. In vivo, arterial and venous blood gases were measured, and survival of the mice to severe global hypoxia was monitored. Ex vivo, expression of various heme biosynthetic enzymes including coproporphyrinogen oxidase (CPOX) was measured, and mitochondrial function was evaluated using Extracellular Flux Analysis. Urine samples were collected to measure the oxidized porphyrinogen intermediates. The in vivo/ex vivo studies were complemented with mitochondrial bioenergetic studies in hepatocytes in vitro. Moreover, the potential effect of H2S on the CPOX promoter was studied in cells expressing a CPOX promoter construct system. Results: The main findings are as follows: (1) CSE−/− mice exhibit elevated red blood cell counts and red blood cell mean corpuscular volumes compared to wild-type mice; (2) these changes are associated with elevated plasma and liver heme levels and (3) these alterations are likely due to an induction of CPOX (the sixth enzyme involved in heme biosynthesis) in CSE−/− mice. (4) Based on in vitro promoter data the promoter activation of CPOX is directly influenced by H2S, the product of CSE. With respect to the potential functional relevance of these findings, (5) the increased circulating red blood cell numbers do not correspond to any detectable alterations in blood gas parameters under resting conditions, (6) nor do they affect the hypoxia tolerance of the animals in an acute severe hypoxia model. However, there may be a functional interaction between the CSE system and the CPOX system in terms of mitochondrial bioenergetics: (7) CSE−/− hepatocytes and mitochondria isolated from them exhibit increased oxidative phosphorylation parameters, and (8) this increase is partially blunted after CPOX silencing. Although heme is essential for the biosynthesis of mitochondrial electron chain complexes, and CPOX is required for heme biosynthesis, (9) the observed functional mitochondrial alterations are not associated with detectable changes in mitochondrial electron transport chain protein expression. Conclusions: The CSE system regulates the expression of CPOX and consequent heme synthesis. These effects in turn, do not influence global oxygen transport parameters, but may regulate mitochondrial electron transport.

Original languageEnglish (US)
Article number113604
JournalBiochemical Pharmacology
Volume169
DOIs
StatePublished - Nov 1 2019

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Coproporphyrinogen Oxidase
Cystathionine
Lyases
Erythropoiesis
Biosynthesis
Electron Transport
Heme
Up-Regulation
Blood
Cells
Mitochondria
Liver
Energy Metabolism
Porphyrinogens
Hepatocytes
Gasotransmitters
Enzymes
Erythrocytes
Gases
Cystathionine gamma-Lyase

Keywords

  • Bioenergetics
  • Circulation
  • Gasotransmitters
  • Mitochondria
  • Oxygen transport
  • Porphyrins
  • Red blood cells

ASJC Scopus subject areas

  • Biochemistry
  • Pharmacology

Cite this

@article{e9ec0cd4fa4148caa5061830a04ce9a6,
title = "Cystathionine-γ-lyase (CSE) deficiency increases erythropoiesis and promotes mitochondrial electron transport via the upregulation of coproporphyrinogen III oxidase and consequent stimulation of heme biosynthesis",
abstract = "Background: Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced by mammalian cells. The current study investigated the potential role of H2S in the regulation of heme biosynthesis using mice deficient in cystathionine gamma-lyase (CSE), one of the three major mammalian H2S-producing enzymes. Methods: Wild-type and global CSE−/− mice, as well as mitochondria prepared from their liver were used. In vivo, arterial and venous blood gases were measured, and survival of the mice to severe global hypoxia was monitored. Ex vivo, expression of various heme biosynthetic enzymes including coproporphyrinogen oxidase (CPOX) was measured, and mitochondrial function was evaluated using Extracellular Flux Analysis. Urine samples were collected to measure the oxidized porphyrinogen intermediates. The in vivo/ex vivo studies were complemented with mitochondrial bioenergetic studies in hepatocytes in vitro. Moreover, the potential effect of H2S on the CPOX promoter was studied in cells expressing a CPOX promoter construct system. Results: The main findings are as follows: (1) CSE−/− mice exhibit elevated red blood cell counts and red blood cell mean corpuscular volumes compared to wild-type mice; (2) these changes are associated with elevated plasma and liver heme levels and (3) these alterations are likely due to an induction of CPOX (the sixth enzyme involved in heme biosynthesis) in CSE−/− mice. (4) Based on in vitro promoter data the promoter activation of CPOX is directly influenced by H2S, the product of CSE. With respect to the potential functional relevance of these findings, (5) the increased circulating red blood cell numbers do not correspond to any detectable alterations in blood gas parameters under resting conditions, (6) nor do they affect the hypoxia tolerance of the animals in an acute severe hypoxia model. However, there may be a functional interaction between the CSE system and the CPOX system in terms of mitochondrial bioenergetics: (7) CSE−/− hepatocytes and mitochondria isolated from them exhibit increased oxidative phosphorylation parameters, and (8) this increase is partially blunted after CPOX silencing. Although heme is essential for the biosynthesis of mitochondrial electron chain complexes, and CPOX is required for heme biosynthesis, (9) the observed functional mitochondrial alterations are not associated with detectable changes in mitochondrial electron transport chain protein expression. Conclusions: The CSE system regulates the expression of CPOX and consequent heme synthesis. These effects in turn, do not influence global oxygen transport parameters, but may regulate mitochondrial electron transport.",
keywords = "Bioenergetics, Circulation, Gasotransmitters, Mitochondria, Oxygen transport, Porphyrins, Red blood cells",
author = "Katalin Modis and V-M Ramanujam and Govar, {Armita Abdollahi} and Ernesto Lopez and Karl Anderson and Rui Wang and Csaba Szabo",
year = "2019",
month = "11",
day = "1",
doi = "10.1016/j.bcp.2019.08.006",
language = "English (US)",
volume = "169",
journal = "Biochemical Pharmacology",
issn = "0006-2952",
publisher = "Elsevier Inc.",

}

TY - JOUR

T1 - Cystathionine-γ-lyase (CSE) deficiency increases erythropoiesis and promotes mitochondrial electron transport via the upregulation of coproporphyrinogen III oxidase and consequent stimulation of heme biosynthesis

AU - Modis, Katalin

AU - Ramanujam, V-M

AU - Govar, Armita Abdollahi

AU - Lopez, Ernesto

AU - Anderson, Karl

AU - Wang, Rui

AU - Szabo, Csaba

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Background: Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced by mammalian cells. The current study investigated the potential role of H2S in the regulation of heme biosynthesis using mice deficient in cystathionine gamma-lyase (CSE), one of the three major mammalian H2S-producing enzymes. Methods: Wild-type and global CSE−/− mice, as well as mitochondria prepared from their liver were used. In vivo, arterial and venous blood gases were measured, and survival of the mice to severe global hypoxia was monitored. Ex vivo, expression of various heme biosynthetic enzymes including coproporphyrinogen oxidase (CPOX) was measured, and mitochondrial function was evaluated using Extracellular Flux Analysis. Urine samples were collected to measure the oxidized porphyrinogen intermediates. The in vivo/ex vivo studies were complemented with mitochondrial bioenergetic studies in hepatocytes in vitro. Moreover, the potential effect of H2S on the CPOX promoter was studied in cells expressing a CPOX promoter construct system. Results: The main findings are as follows: (1) CSE−/− mice exhibit elevated red blood cell counts and red blood cell mean corpuscular volumes compared to wild-type mice; (2) these changes are associated with elevated plasma and liver heme levels and (3) these alterations are likely due to an induction of CPOX (the sixth enzyme involved in heme biosynthesis) in CSE−/− mice. (4) Based on in vitro promoter data the promoter activation of CPOX is directly influenced by H2S, the product of CSE. With respect to the potential functional relevance of these findings, (5) the increased circulating red blood cell numbers do not correspond to any detectable alterations in blood gas parameters under resting conditions, (6) nor do they affect the hypoxia tolerance of the animals in an acute severe hypoxia model. However, there may be a functional interaction between the CSE system and the CPOX system in terms of mitochondrial bioenergetics: (7) CSE−/− hepatocytes and mitochondria isolated from them exhibit increased oxidative phosphorylation parameters, and (8) this increase is partially blunted after CPOX silencing. Although heme is essential for the biosynthesis of mitochondrial electron chain complexes, and CPOX is required for heme biosynthesis, (9) the observed functional mitochondrial alterations are not associated with detectable changes in mitochondrial electron transport chain protein expression. Conclusions: The CSE system regulates the expression of CPOX and consequent heme synthesis. These effects in turn, do not influence global oxygen transport parameters, but may regulate mitochondrial electron transport.

AB - Background: Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced by mammalian cells. The current study investigated the potential role of H2S in the regulation of heme biosynthesis using mice deficient in cystathionine gamma-lyase (CSE), one of the three major mammalian H2S-producing enzymes. Methods: Wild-type and global CSE−/− mice, as well as mitochondria prepared from their liver were used. In vivo, arterial and venous blood gases were measured, and survival of the mice to severe global hypoxia was monitored. Ex vivo, expression of various heme biosynthetic enzymes including coproporphyrinogen oxidase (CPOX) was measured, and mitochondrial function was evaluated using Extracellular Flux Analysis. Urine samples were collected to measure the oxidized porphyrinogen intermediates. The in vivo/ex vivo studies were complemented with mitochondrial bioenergetic studies in hepatocytes in vitro. Moreover, the potential effect of H2S on the CPOX promoter was studied in cells expressing a CPOX promoter construct system. Results: The main findings are as follows: (1) CSE−/− mice exhibit elevated red blood cell counts and red blood cell mean corpuscular volumes compared to wild-type mice; (2) these changes are associated with elevated plasma and liver heme levels and (3) these alterations are likely due to an induction of CPOX (the sixth enzyme involved in heme biosynthesis) in CSE−/− mice. (4) Based on in vitro promoter data the promoter activation of CPOX is directly influenced by H2S, the product of CSE. With respect to the potential functional relevance of these findings, (5) the increased circulating red blood cell numbers do not correspond to any detectable alterations in blood gas parameters under resting conditions, (6) nor do they affect the hypoxia tolerance of the animals in an acute severe hypoxia model. However, there may be a functional interaction between the CSE system and the CPOX system in terms of mitochondrial bioenergetics: (7) CSE−/− hepatocytes and mitochondria isolated from them exhibit increased oxidative phosphorylation parameters, and (8) this increase is partially blunted after CPOX silencing. Although heme is essential for the biosynthesis of mitochondrial electron chain complexes, and CPOX is required for heme biosynthesis, (9) the observed functional mitochondrial alterations are not associated with detectable changes in mitochondrial electron transport chain protein expression. Conclusions: The CSE system regulates the expression of CPOX and consequent heme synthesis. These effects in turn, do not influence global oxygen transport parameters, but may regulate mitochondrial electron transport.

KW - Bioenergetics

KW - Circulation

KW - Gasotransmitters

KW - Mitochondria

KW - Oxygen transport

KW - Porphyrins

KW - Red blood cells

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U2 - 10.1016/j.bcp.2019.08.006

DO - 10.1016/j.bcp.2019.08.006

M3 - Article

VL - 169

JO - Biochemical Pharmacology

JF - Biochemical Pharmacology

SN - 0006-2952

M1 - 113604

ER -