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Metabolism of cysteine in primary hepatocytes from cysteine dioxygenase (CDO1) knockout mice
Author(s) -
Jurkowska Halina,
Hirschberger Lawrence L.,
Roman Heather B,
Wróbel Maria,
Stipanuk Martha H.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.631.25
Subject(s) - cystathionine beta synthase , cysteine , glutathione , chemistry , intracellular , biochemistry , metabolism , microbiology and biotechnology , biology , enzyme
Cysteine dioxygenase (CDO1) knockout mice have higher tissue cysteine levels and metabolize cysteine to H 2 S by alternative desulfhydration pathways catalyzed by cystathionine β‐synthase (CBS) and cystathionine γ‐lyase (CTH), and mercaptopyruvate sulfurtransferase (MPST). We evaluated the effects of a lack of CDO1 in hepatocytes isolated from wild‐type (CDO+/+) or CDO null (CDO−/−) mice. CDO−/− hepatocytes had intracellular cysteine levels that were 1.8 to 2.8‐times the levels in CDO+/+ cells, and similarly elevated glutathione levels. Increasing the cyst(e)ine concentration of the culture medium from 0.2 mM up to 0.7 mM increased intracellular cysteine and glutathione levels only slightly. Thus, both CDO+/+ and CDO−/− cells were able to regulate intracellular cysteine levels, although CDO−/− cells regulated cysteine levels at a higher steady‐state concentration. Cystathionine levels in CDO−/− cells were approximately double those in CDO+/+ cells, consistent with increased metabolism of cysteine (+homocysteine) to cystathionine + H 2 S by CBS. CTH activity, but not abundance, was about 50% higher in CDO−/− cells, consistent with possible upregulation of CTH in CDO−/− cells. The activity of MPST was not significantly increased in CDO−/− cells. Results are similar to those observed in liver of intact CDO−/− mice. Supported by NIH DK056649 and by a “Mobility Plus” fellowship from MNISW (Poland).