Regulation of cystathionine γ-lyase in mammalian cells by hypoxia.

Hydrogen sulfide (H2S), an endogenous signaling molecule in mammalian cells, shows a variety of biological effects. Cystathionine γ-lyase (CSE) is a key enzyme in the trans-sulfuration pathway responsible for the production of endogenous H2S. Whether CSE expression is regulated by hypoxia in mammalian cells remains largely unknown. This study revealed that these regulatory effects changed with time at transcriptional and post-transcriptional levels. Hypoxia regulated CSE expression in mammalian cells in a complex manner; CSE transcription went through a down-regulation and recovery period, while CSE mRNA and protein levels increased during hypoxia. Taken together, the results suggest that CSE can respond to hypoxia through transcriptional and post-transcriptional regulation, and CSE expression can be up-regulated by hypoxia to a certain extent. Therefore, the up-regulation of CSE expression during hypoxia may be useful for increasing the production and concentration of H2S in mammalian cells and indirectly protecting cells from hypoxia.