L-Ascorbate (L-Asc), but not D-isoascorbate (D-Asc) and N-acetylcysteine (NAC) suppress HIF1 ODD-luc reporter activation induced by various inhibitors of HIF prolyl hydroxylase (PHD). The efficiency of suppression by L-Asc was sensitive to the nature of HIF PHD inhibitor chosen for reporter activation. In particular, the inhibitors developed to compete with alpha-ketoglutarate (αKG), were less sensitive to suppression by the physiological range of L-Asc (40-100 μM) than those having a strong iron chelation motif. Challenging those HIF activators in the reporter system with D-Asc demonstrated that the D-isomer, despite exhibiting the same reducing potency with respect to ferric iron, had almost no effect compared to L-Asc. Similarly, no effect on reporter activation was observed with cell-permeable reducing agent NAC up to 1 mM. Docking of L-Asc and D-Asc acid into the HIF PHD2 crystal structure showed interference of Tyr310 with respect to D-Asc. This suggests that L-Asc is not merely a reducing agent preventing enzyme inactivation. Rather, the overall results identify L-Asc as a co-substrate of HIF PHD that may compete for the binding site of αKG in the enzyme active center. This conclusion is in agreement with the results obtained recently in cell-based systems for TET enzymes and jumonji histone demethylases, where L-Asc has been proposed to act as a co-substrate and not as a reducing agent preventing enzyme inactivation.

We performed diagnostic classification of plasma specimens from patients with non-metastatic and metastatic prostate cancer based on pairs of miRNA that have no individual diagnostic significance. Of 230 miRNA detected in plasma specimens, 3 pairs were diagnostically significant. The miRNA pair hsa-miR-19b-3p and hsa-miR-297 demonstrated highest sensitivity and specificity. Among common target genes of these miRNA, CFL2 gene associated with cell mobility was detected.

No abstract

Coronavirus SARS-CoV-2, the cause of the COVID-19 pandemic, enters the cell by binding the cell surface proteins: angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). The expression of these proteins varies significantly in individual organs and tissues of the human body. One of the proteins’ expression regulation mechanisms is based on the activity of the microRNA (miRNA) molecules, small non-coding RNAs, the most important function of which is the post-transcriptional negative regulation of gene expression. The study was aimed to investigate the mechanisms of the interactions between miRNA isoforms and ACE2/TMPRSS2 genes in the colon tissues known for the high level of expression of the described enzymes. The search for interactions was performed using the correlation analysis applied to the publicly available paired mRNA/miRNA sequencing data of colon tissues. Among the others, such miRNAs as miR-30c and miR-200c were identified known for their involvement in the coronavirus infection and acute respiratory distress syndrome pathogenesis. Thus, new potential mechanisms for the ACE2 and TMPRSS2 enzymes regulation were ascertained, as well as their possible functional activity in a cell infected with coronavirus.

We studied the relationship between microcirculation parameters and functional status of HepaRG cells in spheroids and chose an optimal regimen within the physiologically permissible limits of mechanical impact for the cells that maintains the expression of functional genes of the liver.