Does hypoxia-inducible factor 1α play a role in regulating cutaneous oxygen flux in larval zebrafish (Danio rerio)?

2021 ◽  
Author(s):  
Julian J. Parker ◽  
Steve F. Perry
Keyword(s):  
Danio Rerio ◽  
Hypoxia Inducible Factor ◽  
Oxygen Flux ◽  
Hypoxia Inducible Factor 1Α ◽  
Larval Zebrafish

scholarly journals Respirometry and cutaneous oxygen flux measurements reveal a negligible aerobic cost of ion regulation in larval zebrafish (Danio rerio)

2020 ◽  
Vol 223 (18) ◽  
pp. jeb226753
Author(s):  
Julian J. Parker ◽  
Alex M. Zimmer ◽  
Steve F. Perry
Keyword(s):  
Danio Rerio ◽  
Oxygen Flux ◽  
Whole Body ◽  
Uptake Capacity ◽  
Ion Regulation ◽  
Larval Zebrafish ◽  
Morpholino Knockdown ◽  
Rearing Conditions ◽  
Flux Measurements ◽  
Energy Consuming

ABSTRACTFishes living in fresh water counter the passive loss of salts by actively absorbing ions through specialized cells termed ionocytes. Ionocytes contain ATP-dependent transporters and are enriched with mitochondria; therefore ionic regulation is an energy-consuming process. The purpose of this study was to assess the aerobic costs of ion transport in larval zebrafish (Danio rerio). We hypothesized that changes in rates of Na+ uptake evoked by acidic or low Na+ rearing conditions would result in corresponding changes in whole-body oxygen consumption (ṀO2) and/or cutaneous oxygen flux (JO2), measured at the ionocyte-expressing yolk sac epithelium using the scanning micro-optrode technique (SMOT). Larvae at 4 days post-fertilization (dpf) that were reared under low pH (pH 4) conditions exhibited a higher rate of Na+ uptake compared with fish reared under control conditions (pH 7.6), yet they displayed a lower ṀO2 and no difference in cutaneous JO2. Despite a higher Na+ uptake capacity in larvae reared under low Na+ conditions, there were no differences in ṀO2 and JO2 at 4 dpf. Furthermore, although Na+ uptake was nearly abolished in 2 dpf larvae lacking ionocytes after morpholino knockdown of the ionocyte proliferation regulating transcription factor foxi3a, ṀO2 and JO2 were unaffected. Finally, laser ablation of ionocytes did not affect cutaneous JO2. Thus, we conclude that the aerobic costs of ion uptake by ionocytes in larval zebrafish, at least in the case of Na+, are below detection using whole-body respirometry or cutaneous SMOT scans, providing evidence that ion regulation in zebrafish larvae incurs a low aerobic cost.

scholarly journals Loss of hypoxia-inducible factor 1α affects hypoxia tolerance in larval and adult zebrafish ( Danio rerio )

2020 ◽  
Vol 287 (1927) ◽  
pp. 20200798 ◽  
Author(s):  
Milica Mandic ◽  
Carol Best ◽  
Steve F. Perry
Keyword(s):  
Danio Rerio ◽  
Genome Duplication ◽  
Larval Fish ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Tolerance ◽  
Teleost Fishes ◽  
Adult Zebrafish ◽  
Wild Type ◽  
Partial Pressure Of Oxygen ◽  
Hypoxia Inducible Factor 1Α

The coordination of the hypoxic response is attributed, in part, to hypoxia-inducible factor 1α (Hif-1α), a regulator of hypoxia-induced transcription. After the teleost-specific genome duplication, most teleost fishes lost the duplicate copy of Hif-1α, except species in the cyprinid lineage that retained both paralogues of Hif-1α (Hif1aa and Hif1ab). Little is known about the contribution of Hif-1α, and specifically of each paralogue, to hypoxia tolerance. Here, we examined hypoxia tolerance in wild-type (Hif1aa +/+ ab +/+ ) and Hif-1α knockout lines (Hif1aa −/− ; Hif1ab −/− ; Hif1aa −/− ab −/− ) of zebrafish ( Danio rerio ). Critical O 2 tension ( P crit ; the partial pressure of oxygen (PO 2 ) at which O 2 consumption can no longer be maintained) and time to loss of equilibrium (LOE), two indices of hypoxia tolerance, were assessed in larvae and adults. Knockout of both paralogues significantly increased P crit (decreased hypoxia tolerance) in larval fish. Prior exposure of larvae to hypoxia decreased P crit in wild-type fish, an effect mediated by the Hif1aa paralogue. In adults, individuals with a knockout of either paralogue exhibited significantly decreased time to LOE but no difference in P crit . Together, these results demonstrate that in zebrafish, tolerance to hypoxia and improved hypoxia tolerance after pre-exposure to hypoxia (pre-conditioning) are mediated, at least in part, by Hif-1α.

Hypoxia-inducible Factor-1α Suppression in Ovarian Clear-cell Carcinoma Cells by Silibinin Administration

2020 ◽  
Vol 40 (12) ◽  
pp. 6791-6798
Author(s):  
MARIKO MIYAZAWA ◽  
MASANORI YASUDA ◽  
MASAKI MIYAZAWA ◽  
NAOKI OGANE ◽  
TOMOMI KATOH ◽  
...  
Keyword(s):  
Cell Carcinoma ◽  
Clear Cell ◽  
Clear Cell Carcinoma ◽  
Hypoxia Inducible Factor ◽  
Carcinoma Cells ◽  
Ovarian Clear Cell Carcinoma ◽  
Hypoxia Inducible Factor 1Α
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