Hydrogen sulfide promotes calcium uptake in larval zebrafish

Area of Science:

• Physiology
• Molecular Biology
• Environmental Science

Background:

• Hydrogen sulfide (H2S) is recognized as a signaling molecule, but its role in calcium (Ca2+) homeostasis remains largely unexplored.
• Understanding H2S involvement in Ca2+ balance is crucial for comprehending cellular signaling and physiological regulation.

Purpose of the Study:

• To investigate the role of hydrogen sulfide (H2S) in regulating calcium (Ca2+) balance in developing zebrafish (Danio rerio).
• To elucidate the molecular mechanisms underlying H2S-mediated effects on Ca2+ influx and homeostasis.

Main Methods:

• Exposure of zebrafish larvae to H2S donors and assessment of Ca2+ influx and whole-body Ca2+ levels.
• Analysis of Ca2+-transport-related gene expression and utilization of protein kinase A inhibitor (H-89).
• Antisense morpholino knockdown of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) in zebrafish.
• Immunohistochemistry to localize CBSb expression in Na(+)-K(+)-ATPase-rich cells.

Main Results:

• Acute H2S exposure increased Ca2+ influx, while chronic exposure elevated whole-body Ca2+ levels in zebrafish larvae.
• H2S-mediated Ca2+ influx stimulation was abolished by H-89, indicating involvement of cAMP-protein kinase A pathways.
• Ca2+ influx was reduced in CBSb-deficient zebrafish, particularly when acclimated to low-Ca2+ water.
• CBSb expression was localized to Na(+)-K(+)-ATPase-rich cells, suggesting a role in Ca2+ uptake.

Conclusions:

• Hydrogen sulfide (H2S) plays a significant role in promoting Ca2+ influx in zebrafish larvae.
• The H2S signaling pathway for Ca2+ influx involves cAMP-protein kinase A activation and is mediated by CBSb.
• H2S is particularly important for maintaining Ca2+ balance in low-Ca2+ environments, highlighting a novel physiological function.