10.1371/journal.pone.0069512PLoS ONE89-POLN

AM Loong

AR Jayakumar

AT Blei

B Ching

Biyun Ching

C Hermenegildo

C Lorin-Nebel

C Lytle

CA Ecelbarger

D Häussinger

D Liang

DJ Randall

E Kosenko

H Wang

HU Bergmeyer

J Felsentein

JA Payne

Jasmine L. Y. Ong

JB Graham

JL Cooper

Josep V. Planas

K Hernández-Fonseca

K Kurihara

K Piechotta

Kum C. Hiong

KW Peng

L Binstock

L Gerwick

LJ McGuffin

M Haas

MD Miñana

MD Norenberg

ME O’Donnell

ME Raichle

MM Bradford

MR Kaplan

N MacAulay

NLJ Wee

P Ott

P Vigne

PP Hwang

PVB Reddy

RB Darman

RT Worrell

S Hamann

SF Chew

Shit F. Chew

SLA Tay

SW Brusilow

T Kelly

TA Hall

UK Laemmli

V Felipo

VBR Pichili

VI Dzhala

Xiu L. Chen

YK Ip

YL Tay

You R. Chng

YP Yan

Yuen K. Ip

YYM Tng

Zhisheng Hou

PLoS ONE

PubMed

Ip Yuen K.

Hou Zhisheng

Chen Xiu L.

Ong Jasmine L. Y.

Chng You R.

Ching Biyun

Hiong Kum C.

Chew Shit F.

Public Library of Science (PLOS)

, Exposed to Environmental Ammonia or Terrestrial Conditions

Crossref

High Brain Ammonia Tolerance and Down-Regulation of Na+:K+:2Cl- Cotransporter 1b mRNA and Protein Expression in the Brain of the Swamp Eel, Monopterus albus, Exposed to Environmental Ammonia or Terrestrial Conditions

<div>Na+:K+:2Cl- cotransporter 1 (NKCC1) has been implicated in mediating ischemia-, trauma- or ammonia-induced astrocyte swelling/brain edema in mammals. This study aimed to determine the effects of ammonia or terrestrial exposure on ammonia concentrations in the plasma and brain, and the mRNA expression and protein abundance of nkcc/Nkcc in the brain, of the swamp eel Monopterusalbus. Ammonia exposure led to a greater increase in the ammonia concentration in the brain of M. albus than terrestrial exposure. The brain ammonia concentration of M. albus reached 4.5 µmol g-1 and 2.7 µmol g-1 after 6 days of exposure to 50 mmol l-1 NH4Cl and terrestrial conditions, respectively. The full cDNA coding sequence of nkcc1b from M. albus brain comprised 3276 bp and coded for 1092 amino acids with an estimated molecular mass of 119.6 kDa. A molecular characterization indicated that it could be activated through phosphorylation and/or glycosylation by osmotic and/or oxidative stresses. Ammonia exposure for 1 day or 6 days led to significant decreases in the nkcc1b mRNA expression and Nkcc1b protein abundance in the brain of M. albus. In comparison, a significant decrease in nkcc1b mRNA expression was observed in the brain of M. albus only after 6 days of terrestrial exposure, but both 1 day and 6 days of terrestrial exposure resulted in significant decreases in the protein abundance of Nkcc1b. These results are novel because it has been established in mammals that ammonia up-regulates NKCC1 expression in astrocytes and NKCC1 plays an important role in ammonia-induced astrocyte swelling and brain edema. By contrast, our results indicate for the first time that M. albus is able to down-regulate the mRNA and protein expression of nkcc1b/Nkcc1b in the brain when confronted with ammonia toxicity, which could be one of the contributing factors to its extraordinarily high brain ammonia tolerance. </div

Yuen K. Ip (400990)

Zhisheng Hou (460577)

Xiu L. Chen (400992)

Jasmine L. Y. Ong (400993)

You R. Chng (400994)

Biyun Ching (400995)

Kum C. Hiong (446856)

Shit F. Chew (400998)

The Francis Crick Institute

High Brain Ammonia Tolerance and Down-Regulation of Na+:K+:2Cl- Cotransporter 1b mRNA and Protein Expression in the Brain of the Swamp Eel, Monopterus albus, Exposed to Environmental Ammonia or Terrestrial Conditions

Na(+):K(+):2Cl(-) cotransporter 1 (NKCC1) has been implicated in mediating ischemia-, trauma- or ammonia-induced astrocyte swelling/brain edema in mammals. This study aimed to determine the effects of ammonia or terrestrial exposure on ammonia concentrations in the plasma and brain, and the mRNA expression and protein abundance of nkcc/Nkcc in the brain, of the swamp eel Monopterusalbus. Ammonia exposure led to a greater increase in the ammonia concentration in the brain of M. albus than terrestrial exposure. The brain ammonia concentration of M. albus reached 4.5 µmol g(-1) and 2.7 µmol g(-1) after 6 days of exposure to 50 mmol l(-1) NH4Cl and terrestrial conditions, respectively. The full cDNA coding sequence of nkcc1b from M. albus brain comprised 3276 bp and coded for 1092 amino acids with an estimated molecular mass of 119.6 kDa. A molecular characterization indicated that it could be activated through phosphorylation and/or glycosylation by osmotic and/or oxidative stresses. Ammonia exposure for 1 day or 6 days led to significant decreases in the nkcc1b mRNA expression and Nkcc1b protein abundance in the brain of M. albus. In comparison, a significant decrease in nkcc1b mRNA expression was observed in the brain of M. albus only after 6 days of terrestrial exposure, but both 1 day and 6 days of terrestrial exposure resulted in significant decreases in the protein abundance of Nkcc1b. These results are novel because it has been established in mammals that ammonia up-regulates NKCC1 expression in astrocytes and NKCC1 plays an important role in ammonia-induced astrocyte swelling and brain edema. By contrast, our results indicate for the first time that M. albus is able to down-regulate the mRNA and protein expression of nkcc1b/Nkcc1b in the brain when confronted with ammonia toxicity, which could be one of the contributing factors to its extraordinarily high brain ammonia tolerance

Yuen K Ip

Xiu L Chen

Jasmine L Y Ong

You R Chng

Kum C Hiong

Shit F Chew

Directory of Open Access Journals

High brain ammonia tolerance and down-regulation of Na+:K+:2Cl(-) Cotransporter 1b mRNA and protein expression in the brain of the Swamp Eel, Monopterus albus, exposed to environmental ammonia or terrestrial conditions.

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High Brain Ammonia Tolerance and Down-Regulation of Na+:K+:2Cl- Cotransporter 1b mRNA and Protein Expression in the Brain of the Swamp Eel, Monopterus albus, Exposed to Environmental Ammonia or Terrestrial Conditions

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Public Library of Science (PLOS)

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The Francis Crick Institute

Directory of Open Access Journals