ZFIN ID: ZDB-PUB-200807-7
Expression of ion-transport genes in ionocytes isolated from larval zebrafish (Danio rerio) exposed to acidic or Na+ deficient water
Shir-Mohammadi, K., Perry, S.F.
Date: 2020
Source: American journal of physiology. Regulatory, integrative and comparative physiology   319(4): R412-R427 (Journal)
Registered Authors: Perry, Steve F.
Keywords: FACS, H+-ATPase rich (HR) cell, Ion regulation, immunohistochemistry, mRNA
MeSH Terms:
  • Animals
  • Gills/metabolism
  • Hydrogen-Ion Concentration
  • Ion Transport/genetics*
  • Proton-Translocating ATPases/genetics*
  • Proton-Translocating ATPases/metabolism
  • Sodium/metabolism
  • Sodium-Hydrogen Exchangers/genetics*
  • Sodium-Hydrogen Exchangers/metabolism
  • Water*
  • Zebrafish
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
PubMed: 32755465 Full text @ Am. J. Physiol. Regul. Integr. Comp. Physiol.
In zebrafish (Danio rerio), a specific ionocyte subtype, the H+-ATPase-rich (HR) cell, is presumed to be a significant site of transepithelial Na+ uptake/acid-secretion. During acclimation to environments differing in ionic composition or pH, ionic and acid-base regulation are achieved by adjustments to the activity level of HR cell ion transport proteins. In previous studies, the quantitative assessment of mRNA levels for genes involved in ionic and acid-base regulation relied on measurements using homogenates derived from whole body (larvae) or gill (adult). Such studies cannot distinguish whether any differences in gene expression arise from adjustments of ionocyte subtype numbers, or transcriptional regulation specifically within individual ionocytes. The goal of the present study was to use florescence activated cell sorting (FACS) to separate the HR cells from other cellular sub-populations to facilitate the measurement of gene expression of HR cell-specific transporters and enzymes from larvae exposed to low pH (pH 4.0) or low Na+ (5 μM) conditions. The data demonstrate that treatment of larvae with acidic water for 4 days post fertilization caused cell-specific increases in H+ATPase (atp6v1aa), ca17a, ca15a, nhe3b and rhcgb mRNA in addition to increases in mRNA linked to cell proliferation. In fish exposed to low Na+, expression of nhe3b and rhcgb was increased owing to HR cell-specific regulation as well as elevated numbers of HR cells. Thus, the results of this study demonstrate that acclimation to low pH or low Na+ environmental conditions is facilitated by HR cell-specific transcriptional control and by HR cell proliferation.