Estrogen-related receptor γ2 controls NaCl uptake to maintain ionic homeostasis

2021 ◽  
Author(s):  
Shang-Wu Shih ◽  
Jia-Jiun Yan ◽  
Yi-Hsing Wang ◽  
Yi-Ling Tsou ◽  
Ling Chiu ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Body Fluid ◽  
Whole Body ◽  
Ionic Homeostasis ◽  
Ion Regulation ◽  
Expression Levels ◽  
Morpholino Knockdown ◽  
Oryzias Melastigma ◽  
Euryhaline Teleost

Estrogen-related receptors (ERRs) are known to function in mammalian kidney as key regulators of ion transport-related genes; however, a comprehensive understanding of the physiological functions of ERRs in vertebrate body fluid ionic homeostasis is still elusive. Here, we used medaka (Oryzias melastigma), a euryhaline teleost, to investigate how ERRs are involved in ion regulation. After transferring medaka from hypertonic seawater to hypotonic freshwater (FW), the mRNA expression levels of errγ2 were highly upregulated, suggesting that ERRγ2 may play a crucial role in ion uptake. In situ hybridization and immunofluorescence staining showed that errγ2 was specifically expressed in ionocytes, the cells responsible for Na+/Cl- transport. In normal FW, ERRγ2 morpholino knockdown caused reductions in the mRNA expression of Na+/Cl- cotransporter (NCC), the number of NCC ionocytes, Na+/Cl- influxes of ionocytes, and whole-body Na+/Cl- contents. In FW with low Na+ and low Cl-, the expression levels of mRNA for Na+/H+ exchanger 3 (NHE3) and NCC were both decreased in ERRγ2 morphants. Treating embryos with DY131, an agonist of ERRγ, increased the whole-body Na+/Cl- contents and ncc mRNA expression in ERRγ2 morphants. As such, medaka ERRγ2 may control Na+/Cl- uptake by regulating ncc and/or nhe3 mRNA expression and ionocyte number, and these regulatory actions may be subtly adjusted depending on internal and external ion concentrations. These findings not only provide new insights into the underpinning mechanism of actions of ERRs, but also enhance our understanding of their roles in body fluid ionic homeostasis for adaptation to changing environments during vertebrate evolution.

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 Fluctuating Gene Expression and Localized Cellular Distribution of Vasoactive Intestinal Contractor (VIC) in Mouse Uterus

2000 ◽  
Vol 48 (5) ◽  
pp. 699-707 ◽  
Author(s):  
Tsuyoshi Uchide ◽  
Hiromi Masuda ◽  
Yun-Sik Lee ◽  
Yasushi Makiyama ◽  
Youji Mitsui ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Mrna Expression ◽  
Pregnant Mouse ◽  
Cellular Distribution ◽  
Mouse Uterus ◽  
Expression Levels ◽  
Myometrial Cells ◽  
Early Postpartum ◽  
Immunohistochemical Studies

SUMMARY To understand the physiological roles of vasoactive intestinal contractor (VIC) and endothelin-2 (ET-2) in the uterus, we examined the expression levels of VIC mRNA by real-time quantitative reverse transcription-linked polymerase chain reaction (RT-PCR) and characterized the cellular distribution of VIC peptide and mRNA by immunostaining and in situ hybridization in mouse uterus. In pregnant mouse uterus, VIC mRNA expression changed considerably between Days 10.5 and 12.5 of pregnancy. The expression levels were significantly ( p<0.05) higher (approximately fivefold) in the later stage of pregnancy (Days 12.5-17.5) than in the earlier stage (Days 7.5-10.5). In nonpregnant uterus, VIC mRNA expression was significantly ( p<0.05) higher (approximately threefold) in proestrus and estrus than in diestrus. Immunohistochemical studies demonstrated the presence of VIC peptide in endometrial epithelial cells, myometrial cells, and vascular smooth muscle cells during the estrous cycle and pregnancy and after parturition. Notably, myometrial cells showed dominant immunostaining in proestrus and estrus, in the later pregnancy stage, and in the early postpartum period, analogous to the expression pattern of VIC mRNA. In situ hybridization confirmed localization of VIC mRNA in myometrial cells. These findings suggest that VIC may play an important role in the function of myometrial cells.

scholarly journals Hydrogen sulfide promotes calcium uptake in larval zebrafish

2015 ◽  
Vol 309 (1) ◽  
pp. C60-C69 ◽  
Author(s):  
Raymond W. M. Kwong ◽  
Steve F. Perry
Keyword(s):  
Hydrogen Sulfide ◽  
Protein Kinase ◽  
Mrna Expression ◽  
Protein Kinase A ◽  
Whole Body ◽  
In Vivo Model ◽  
Morpholino Knockdown ◽  
Isoform B ◽  
Kinase A

Hydrogen sulfide (H2S) can act as a signaling molecule for various ion channels and/or transporters; however, little is known about its potential involvement in Ca2+ balance. Using developing zebrafish ( Danio rerio) as an in vivo model system, the present study demonstrated that acute exposure to H2S donors increased Ca2+ influx at 4 days postfertilization, while chronic (3-day) exposure caused a rise in whole body Ca2+ levels. The mRNA expression of Ca2+-transport-related genes was unaffected by H2S exposure, suggesting that posttranscriptional modifications were responsible for the altered rates of Ca2+ uptake. Indeed, treatment of fish with the protein kinase A inhibitor H-89 abolished the H2S-mediated stimulation of Ca2+ influx, suggesting that H2S increased Ca2+ influx by activating cAMP-protein kinase A pathways. Cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) are two key enzymes in the endogenous synthesis of H2S. Using an antisense morpholino knockdown approach, we demonstrated that Ca2+ influx was reduced in CBS isoform b (CBSb)- but not in CSE-deficient fish. Interestingly, the reduction in Ca2+ influx in CBSb-deficient fish was observed only in fish that were acclimated to low-Ca2+ water (i.e., 25 μM Ca2+; control: 250 μM Ca2+). Similarly, mRNA expression of cbsb but not cse was increased in fish acclimated to low-Ca2+ water. Results from whole-mount immunohistochemistry further revealed that CBSb was expressed in Na+-K+-ATPase-rich cells, which are implicated in Ca2+ uptake in zebrafish larvae. Collectively, the present study suggests a novel role for H2S in promoting Ca2+ influx, particularly in a low-Ca2+ environment.

Evidence that SLC26 anion transporters mediate branchial chloride uptake in adult zebrafish (Danio rerio)

2009 ◽  
Vol 297 (4) ◽  
pp. R988-R997 ◽  
Author(s):  
S. F. Perry ◽  
B. Vulesevic ◽  
M. Grosell ◽  
M. Bayaa
Keyword(s):  
Mrna Expression ◽  
Danio Rerio ◽  
Whole Body ◽  
Mrna Levels ◽  
Adult Zebrafish ◽  
Chloride Uptake ◽  
Anion Transporters ◽  
Anion Transporter ◽  
Normal Water

Experiments were performed to test the hypothesis that three members of the SLC26 anion transporter gene family (SLC26a3, A4, and A6; hereafter termed za3, za4, and za6) mediate branchial Cl−/HCO3− exchange in adult zebrafish ( Danio rerio). Real-time RT-PCR demonstrated that the gill expressed relatively high levels of za6 mRNA; za3 and za4 mRNA, while present, were less abundant. Also, za4 and za6 were expressed at relatively high levels in the kidney. The results of in situ hybridization or immunocytochemistry (za3 only) experiments performed on gill sections revealed that the SLC26 transporters were predominantly expressed on the filament epithelium (especially within the interlamellar regions) and to a lesser extent on the lamellar epithelium at the base of lamellae. This distribution pattern suggests that the SLC26 anion transporters are localized to mitochondrion-rich cells (ionocytes). Transferring fish to water containing low [Cl−] (0.02 mmol/l) resulted in significant increases in branchial SLC26 mRNA expression after 5–10 days of exposure relative to fish raised in normal water [Cl−] (0.4 mmol/l); transferring fish to Cl−-enriched water (2.0 mmol/l) was without effect on mRNA levels. Transferring fish to water containing elevated levels of NaHCO3 (10–12.5 mmol/l) caused marked increases in branchial SLC26 mRNA expression between 3 and 10 days of transfer that was associated with a significant 40% increase in Cl− uptake (as measured upon return to normal water after 7 days). A decrease in whole body net acid excretion (equivalent to an increase in net base excretion) in fish previously maintained in high [NaHCO3] water, concurrent with increases in Cl− uptake and SLC26 mRNA levels, suggests a role for these anion transporters in Cl− uptake and acid-base regulation owing to their Cl−/HCO3− exchange activities.

scholarly journals Involvement of the calcium-sensing receptor in calcium homeostasis in larval zebrafish exposed to low environmental calcium

2014 ◽  
Vol 306 (4) ◽  
pp. R211-R221 ◽  
Author(s):  
Raymond W. M. Kwong ◽  
Dan Auprix ◽  
Steve F. Perry
Keyword(s):  
In Situ Hybridization ◽  
Confocal Microscopy ◽  
Mrna Expression ◽  
Danio Rerio ◽  
Whole Body ◽  
Calcium Sensing Receptor ◽  
Larval Zebrafish ◽  
Calcium Sensing ◽  
Normal Water

The involvement of the calcium-sensing receptor (CaSR) in Ca2+ homeostasis was investigated in larval zebrafish, Danio rerio. The expression of CaSR mRNA was first observed at 3 h posfertilization (hpf) and increased with development until plateauing at ∼48 hpf. At 4 dpf, CaSR mRNA was increased in fish acclimated to low Ca2+ water (25 μM vs. 250 μM in normal water). Using immunohistochemistry and confocal microscopy, we demonstrated that the CaSR is expressed in the olfactory epithelium, neuromasts, ionocytes on the yolk sac epithelium, and corpuscles of Stannius. Results of double immunohistochemistry and/or in situ hybridization indicated that the CaSR is localized to a subset of mitochondrion-rich ionocytes enriched with Na+/K+-ATPase and epithelial Ca2+ channel ( ecac). Translational knockdown of the CaSR prevented 4 dpf larvae from regulating whole body Ca2+ levels when exposed to a low Ca2+ environment. Further, the increases in ecac mRNA expression and Ca2+ influx, normally associated with exposure to low-Ca2+ water, were prevented by CaSR knockdown. These findings demonstrate that larval zebrafish lacking the CaSR lose their ability to regulate Ca2+ when confronted with a low-Ca2+ environment. Results from real-time PCR suggested that the mRNA expression of the hypocalcemic hormone stanniocalcin ( stc-1) remained elevated in the CaSR morphants following acclimation to low-Ca2+ water. Overall, the results suggest that the CaSR is critical for Ca2+ homeostasis in larval zebrafish exposed to low environmental Ca2+ levels, possibly owing to its modulation of stanniocalcin mRNA expression.

scholarly journals Lack of Overt FGF21 Resistance in Two Mouse Models of Obesity and Insulin Resistance

Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Clarence Hale ◽  
Michelle M. Chen ◽  
Shanaka Stanislaus ◽  
Narumol Chinookoswong ◽  
Todd Hager ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Energy Homeostasis ◽  
Tissue Expression ◽  
Whole Body ◽  
Fibroblast Growth Factor 21 ◽  
Disease Models ◽  
Response Curves ◽  
Fgf Receptor ◽  
Expression Levels ◽  
Erk Phosphorylation

Circulating levels of fibroblast growth factor 21 (FGF21), a metabolic regulator of glucose, lipid, and energy homeostasis, are elevated in obese diabetic subjects, raising questions about potential FGF21 resistance. Here we report tissue expression changes in FGF21 and its receptor components, and we describe the target-organ and whole-body responses to FGF21 in ob/ob and diet-induced obese (DIO) mice. Plasma FGF21 concentrations were elevated 8- and 16-fold in DIO and ob/ob mice, respectively, paralleling a dramatic increase in hepatic FGF21 mRNA expression. Concurrently, expression levels of βKlotho, FGF receptor (FGFR)-1c, and FGFR2c were markedly down-regulated in the white adipose tissues (WAT) of ob/ob and DIO mice. However, dose-response curves of recombinant human FGF21 (rhFGF21) stimulation of ERK phosphorylation in the liver and WAT were not right shifted in disease models, although the magnitude of induction in ERK phosphorylation was partially attenuated in DIO mice. Whole-body metabolic responses were preserved in ob/ob and DIO mice, with disease models being more sensitive and responsive than lean mice to the glucose-lowering and weight-loss effects of rhFGF21. Endogenous FGF21 levels, although elevated in diseased mice, were below the half-maximal effective concentrations of rhFGF21, suggesting a state of relative deficiency. Hepatic and WAT FGF21 mRNA expression levels declined after rhFGF21 treatment in the absence of the increased expression levels of βKlotho and FGFR. We conclude that overt FGF21 resistance was not evident in the disease models, and increased hepatic FGF21 expression as a result of local metabolic changes is likely a major cause of elevated circulating FGF21 levels.

scholarly journals Tissue-specific Nutrient Metabolism in the Liver and Muscle of Juvenile Blunt Snout Bream (Megalobrama Amblycephala) in Response to Dietary Methionine Levels

2021 ◽  
Author(s):  
Ke Ji ◽  
Hualiang Liang ◽  
Mingchun Ren ◽  
Xianping Ge ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Mrna Expression ◽  
Binding Protein ◽  
Whole Body ◽  
Megalobrama Amblycephala ◽  
Mrna Levels ◽  
Nutrient Metabolism ◽  
Tissue Specific ◽  
Expression Levels ◽  
Mrna Expression Levels

Abstract BackgroundMethionine is an essential amino acid, that affects the metabolism of protein, lipid and glucose. However, the metabolic polytrophic response in the liver and muscle of juvenile Megalobrama amblycephala to dietary methionine levels is unclear.ResultsThe 0.84% methionine diet significantly improved the growth performance compared with the 0.40% diet. Dietary methionine levels had no marked effects on plasma parameters or whole body composition of juveniles. The protein levels of phospho-phosphatidylinositol 3-kinase, protein kinase B, phospho-eukaryotic initiation factor 4E binding protein-1 (p-4E-BP1), 4E-BP1 and ribosomal protein S6 kinase 1, in the liver of fish fed the 0.84% diet were higher than those in fish fed the 0.40% diet. While in muscle, these proteins showed the opposite trend. The mRNA levels of the muscular lipid synthesis associated genes: sterol regulatory element-binding protein 1 (SREBP1), fatty acid synthetase (FAS) and acetyl-CoA carboxylase (ACC), were significantly upregulated by the 1.28% methionine diet; while hepatic SREBP1, FAS and ACC mRNA expression levels were increased by 0.40% methionine. In addition, 1.28% dietary methionine significantly induced fatty acid β-oxidation and lipolysis of the liver and muscle via increased carnitine palmitoyl transferase 1, peroxisome proliferator activated receptor alpha, lipoprotein lipase and lipase expression levels. Compared with 0.40% dietary methionine, 1.28% methionine enhanced the mRNA levels of the hepatic gluconeogenesis related genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase, and the muscular glycolysis related genes phosphofructokinase (PFK) and pyruvate kinase (PK). The mRNA expression levels of hepatic PFK, PK and glucokinase were markedly upregulated by the 0.84% methionine diet compared with the 1.28% diet. In addition, muscular PEPCK and glycogen synthase, and hepatic glucose transporters 2 mRNA levels were induced by 1.28% methionine. ConclusionThe study showed that optimal methionine levels could enhance the growth of juvenile Megalobrama amblycephala, and the nutrient metabolism response to dietary methionine in the liver and muscle was tissue-specific.

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