Energy and nitrogenous waste from glutamate/glutamine catabolism facilitates acute osmotic adjustment in non-neuroectodermal branchial cells

Huang, Pei-Chen, Liu, Tzu-Yen, Hu, Marian Y., Casties, Isabel and Tseng, Yung-Che (2020) Energy and nitrogenous waste from glutamate/glutamine catabolism facilitates acute osmotic adjustment in non-neuroectodermal branchial cells Scientific Reports, 10 (1). Art.Nr. 9460. DOI 10.1038/s41598-020-65913-1.

[img]
Preview
Text
s41598-020-65913-1.pdf - Published Version
Available under License Creative Commons: Attribution 4.0.

Download (4Mb) | Preview
[img]
Preview
Text
41598_2020_65913_MOESM1_ESM.pdf - Supplemental Material
Available under License Creative Commons: Attribution 4.0.

Download (1616Kb) | Preview

Supplementary data:

Abstract

Maintenance of homeostasis is one of the most important physiological responses for animals upon osmotic perturbations. Ionocytes of branchial epithelia are the major cell types responsible for active ion transport, which is mediated by energy-consuming ion pumps (e.g., Na+-K+-ATPase, NKA) and secondary active transporters. Consequently, in addition to osmolyte adjustments, sufficient and immediate energy replenishment is essenttableial for acclimation to osmotic changes. In this study, we propose that glutamate/glutamine catabolism and trans-epithelial transport of nitrogenous waste may aid euryhaline teleosts Japanese medaka (Oryzias latipes) during acclimation to osmotic changes. Glutamate family amino acid contents in gills were increased by hyperosmotic challenge along an acclimation period of 72 hours. This change in amino acids was accompanied by a stimulation of putative glutamate/glutamine transporters (Eaats, Sat) and synthesis enzymes (Gls, Glul) that participate in regulating glutamate/glutamine cycling in branchial epithelia during acclimation to hyperosmotic conditions. In situ hybridization of glutaminase and glutamine synthetase in combination with immunocytochemistry demonstrate a partial colocalization of olgls1a and olgls2 but not olglul with Na+/K+-ATPase-rich ionocytes. Also for the glutamate and glutamine transporters colocalization with ionocytes was found for oleaat1, oleaat3, and olslc38a4, but not oleaat2. Morpholino knock-down of Sat decreased Na+ flux from the larval epithelium, demonstrating the importance of glutamate/glutamine transport in osmotic regulation. In addition to its role as an energy substrate, glutamate deamination produces NH4+, which may contribute to osmolyte production; genes encoding components of the urea production cycle, including carbamoyl phosphate synthetase (CPS) and ornithine transcarbamylase (OTC), were upregulated under hyperosmotic challenges. Based on these findings the present work demonstrates that the glutamate/glutamine cycle and subsequent transepithelial transport of nitrogenous waste in branchial epithelia represents an essential component for the maintenance of ionic homeostasis under a hyperosmotic challenge.

Document Type: Article
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-OEB Ökosystembiologie des Ozeans
Kiel University
Refereed: Yes
DOI etc.: 10.1038/s41598-020-65913-1
ISSN: 2045-2322
Date Deposited: 22 Jun 2020 09:14
Last Modified: 22 Jun 2020 09:14
URI: http://eprints.uni-kiel.de/id/eprint/49929

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...