Coenzyme Q10 upregulates SQOR and downregulates CBS, CSE

Another paper that shows downregulation of transsulfuration pathway enzymes (CBS/CSE) by Coenzyme Q10, and particularly due to upregulation of SQOR.

Here, using biased and unbiased approaches, we show that supraphysiological levels of CoQ10 induces an increase in the expression of SQOR in skin fibroblasts from control subjects and patients with mutations in Complex I subunits genes or CoQ biosynthetic genes.

This increase of SQOR induces the downregulation of the cystathionine β-synthase and cystathionine γ-lyase, two enzymes of the transsulfuration pathway, the subsequent downregulation of serine biosynthesis and the adaptation of other sulfide linked pathways, such as folate cycle, nucleotides metabolism and glutathione system. These metabolic changes are independent of the presence of sulfur aminoacids, are confirmed in mouse models, and are recapitulated by overexpression of SQOR, further proving that the metabolic effects of CoQ10 supplementation are mediated by the overexpression of SQOR.

Also from this paper:

Coenzyme Q (CoQ) deficiency severely decreases the levels of Sulfide Quinone Oxidoreductase (SQOR), the first enzyme in the mitochondrial H2S oxidation pathway. Thus, the decrease in SQOR leads to an impairment of H2S oxidation, leading to accumulation of H2S and depletion on the glutathione system.