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Indoxyl sulfate (IS), a uremic toxin, is a physiologically active sulfated metabolite, specifically in kidney failure patients. Our previous studies have shown that IS downregulates phagocytic immune function in a differentiated HL-60 human macrophage cell model. However, it remains unclear whether IS exerts similar effects on macrophage function in other cell types or in lipopolysaccharide (LPS)-sensitive immune cell models. Therefore, this study aimed to investigate the effects of IS on intracellular oxidation levels and phagocytic activity in a differentiated U937 human macrophage cell model, both in the absence and presence of LPS. Our results demonstrated that IS significantly increases intracellular oxidation levels and decreases phagocytic activity, particularly in cells activated by LPS. Furthermore, we found that 2-acetylphenothiazine, an NADH oxidase inhibitor, attenuates the effects of IS in LPS-activated macrophage cells. Representative antioxidants, trolox, α-tocopherol, and ascorbic acid, significantly mitigated the effects of IS on the macrophages responding to LPS. [ABSTRACT FROM AUTHOR]

The cytosolic sulfotransferase (SULT) SULT2A1 is known to mediate the sulfation of DHEA as well as some other hydroxysteroids such aspregnenolone. The present study was designedtoinvestigate how genetic polymorphismsof the human SULT2A1 gene may affect the sulfation of DHEA and pregnenolone. Online databases were systematically searched to identify human SULT2A1 single nucleotide polymorphisms (SNPs). Of the 98 SULT2A1 non-synonymous coding SNPs identified, seven were selected for further investigation. Site-directed mutagenesis was used to generate cDNAs encoding these seven SULT2A1 allozymes, which were expressed in BL21 Escherichia coli cells and purified by glutathione-Sepharose affinity chromatography. Enzymatic assays revealed that purified SULT2A1 allozymes displayed differential sulfating activity toward both DHEA and pregnenolone. Kinetic analyses showed further differential catalytic efficiency and substrate affinity of the SULT2A1 allozymes, in comparison with wild-type SULT2A1. These findings provided useful information concerning the effects of genetic polymorphisms on the sulfating activity of SULT2A1 allozymes. Key words: single nucleotide polymorphisms, cytosolic sulfotransferase, SULT, SULT2A1, sulfation, dehydroepiandrosterone, DHEA, pregnenolone. La sulfotransferase (SULT) cytosolique SULT2A1 est connue pour catalyser la sulfatation de la dehydroepiandrosterone (DHEA) de meme que d'autres hydroxysteroides comme la pregnenolone. La presente etude a ete concue pour examiner comment les polymorphismes genetiques du gene SULT2A1 humain peuvent affecter la sulfatation de la DHEA et de la pregnenolone. Des bases de donnees en ligne ont ete systematiquement fouillees afin d'identifier des polymorphismes mononucleotidiques (SNP) deSULT2A1 humain. Des 98 SNP codants non-synonymes de SULT2A1 identifies, sept ont ete choisis pour des etudes plus approfondies.La mutagenese dirigee aete utilisee pour generer des ADNc codant ces sept allozymes de SULT2A1, qui ont ete exprimees chez Escherichia coli BL21 et purifiees par chromatographie d'affinite sur glutathion-Sepharose. Les dosages enzymatiques ont revele que les allozymes de SULT2A1 purifiees presentaient des activites de sulfatation differentielles envers la DHEA et la pregnenolone. Les analyses cinetiques ont en outre montre la differenciation de l'efficacite catalytique et de l'affinite pour les substrats des allozymes de SULT2A1, comparativement a SULT2A1 sauvage. Ces resultats ont fourni une information utile en ce qui concerne les effets des polymorphismes genetiques sur l'activite de sulfatation des allozymes de SULT2A1. [Traduit par la Redaction] Mots-cles : polymorphismes mononucleotidiques, sulfotransferase cytosolique, SULT, SULT2A1, sulfatation, dehydroepiandrosterone, DHEA, pregnenolone., Introduction In the human body, the adrenal cortex constitutes a major site for the biosynthesis and secretionofa varietyof steroid hormones including pregnenolone, dehydroepiandrosterone (DHEA), and androstenedione (Turcu et al. 2014). [...]