title: Hydrogen sulfide promotes calcium uptake in larval zebrafish.
abstract: 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 Ca(2+) balance. Using developing zebrafish (Danio rerio) as an in vivo model system, the present study demonstrated that acute exposure to H2S donors increased Ca(2+) influx at 4 days postfertilization, while chronic (3-day) exposure caused a rise in whole body Ca(2+) levels. The mRNA expression of Ca(2+)-transport-related genes was unaffected by H2S exposure, suggesting that posttranscriptional modifications were responsible for the altered rates of Ca(2+) uptake. Indeed, treatment of fish with the protein kinase A inhibitor H-89 abolished the H2S-mediated stimulation of Ca(2+) influx, suggesting that H2S increased Ca(2+) 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 Ca(2+) influx was reduced in CBS isoform b (CBSb)- but not in CSE-deficient fish. Interestingly, the reduction in Ca(2+) influx in CBSb-deficient fish was observed only in fish that were acclimated to low-Ca(2+) water (i.e., 25 μM Ca(2+); control: 250 μM Ca(2+)). Similarly, mRNA expression of cbsb but not cse was increased in fish acclimated to low-Ca(2+) water. Results from whole-mount immunohistochemistry further revealed that CBSb was expressed in Na(+)-K(+)-ATPase-rich cells, which are implicated in Ca(2+) uptake in zebrafish larvae. Collectively, the present study suggests a novel role for H2S in promoting Ca(2+) influx, particularly in a low-Ca(2+) environment.
authors.affiliation: Department of Biology, University of Ottawa, Ottawa, Ontario, Canada wkwong@uottawa.ca.
authors.forename: Raymond W M
authors.initials: RW
authors.lastname: Kwong
authors.affiliation: Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Steve F
authors.initials: SF
authors.lastname: Perry
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002118:Calcium / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003541:Cystathionine beta-Synthase / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D017136:Ion Transport; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology*; D060172:Morpholinos / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D009946:Organothiophosphorus Compounds / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013440:Sulfides / Q000494:pharmacology*; D013997:Time Factors; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: C529376:GYY 4137; D009025:Morpholines; D060172:Morpholinos; D016376:Oligonucleotides, Antisense; D009946:Organothiophosphorus Compounds; D047428:Protein Kinase Inhibitors; D013440:Sulfides; D029961:Zebrafish Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D003541:Cystathionine beta-Synthase; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium; C033479:sodium sulfide; D006862:Hydrogen Sulfide
keywords: ECaC; NaR cell; calcium; hydrogen sulfide; ionocyte; protein kinase A; zebrafish