Glutathione reductase (Glr1) activity controls cellular glutathione
and reactive oxygen species (ROS). We previously
demonstrated two predominant methylglyoxal scavengers–
NAD(H)-linked methylglyoxal oxidoreductase (Mgd1) and
alcohol dehydrogenase 1 (Adh1)–in glutathione-depleted γ-
glutamyl cysteinyl synthetase-disrupted Candida albicans.
However, experimental evidence for Candida pathophysiology
lacking the enzyme activities of Mgd1 and Adh1 on glutathione-
dependent redox regulation remains unclear. Herein,
we have aimed to demonstrate that glutathione-dependent
enzyme activities coupled with cellular ROS changes is regulated
by methylglyoxal accumulation in Δmgd1/Δadh1 double
disruptants. Δmgd1/Δadh1 showed severe growth defects
and G1-phase cell cycle arrest. The observed complementary
and reciprocal methylglyoxal-oxidizing and methylglyoxalreducing
activities between Δmgd1 and Δadh1 were not always
exhibited in Δmgd1/Δadh1. Although intracellular accumulation
of methylglyoxal and pyruvate was shown in all
disruptants, to a greater or lesser degree, methylglyoxal was
particularly accumulated in the Δmgd1/Δadh1 double disruptant.
While cellular ROS significantly increased in Δmgd1
and Δadh1 as compared to the wild-type, Δmgd1/Δadh1 underwent
a decrease in ROS in contrast to Δadh1. Despite the
experimental findings underlining the importance of the
undergoing unbalanced redox state of Δmgd1/Δadh1, glutathione-
independent antioxidative enzyme activities did not
change during proliferation and filamentation. Contrary to
the significantly lowered glutathione content and Glr1 enzyme
activity, the activity staining-based glutathione peroxidase
activities concomitantly increased in this mutant. Additionally,
the enhanced GLR1 transcript supported our results in
Δmgd1/Δadh1, indicating that deficiencies of both Adh1 and
Mgd1 activities stimulate specific glutathione-dependent enzyme
activities. This suggests that glutathione-dependent redox
regulation is evidently linked to C. albicans pathogenicity
under the control of methylglyoxal-scavenging activities.
Citations
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Roles of alcohol dehydrogenase 1 in the biological activities of
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Ziqi Wang, Qi Zhang, Haoying Zhang, Yuanyuan Lu Critical Reviews in Microbiology.2024; : 1. CrossRef