Mitochondria-targeted triphenylphosphonium-based compounds do not affect estrogen receptor α

What DNA Polymerase Is Preferable in miRNA Assay Coupled with Isothermal Circular Strand Displacement Polymerization Reaction (ICSDPR)?

The products generated in the isothermal circular strand displacement polymerization reaction (ICSDPR) initiated with miRNA-141 were studied. The obtained results demonstrated that if ICSDPR was catalyzed with Large Klenow Fragment (lKF), the canonical duplex and some byproducts, which were not described previously, were observed. The HMW byproducts were shown to be produced as a result of lKF-insisted polymerization of capture hairpin (HP) used in ICSDPR. Contrary to original HP, HMW byproducts are not capture probes because upon polymerization they lack the ability to bind the target. Interestingly, the replacement of lKF with Klenow Fragment (3'-5' exo-) (KFexo-) prevented the generation of HMW byproducts but did not affect the synthesis of other ICSDPR products. In the presence of both DNA polymerases, the second byproduct, named target-dependent byproduct (TD byproduct), was formed when the capture HP and target sequence formed a perfect duplex. Using an imperfect complex with unpaired nucleotides at the 3'-end of the target sequence prevented the formation of TD byproduct in ICSDPR. The knowledge of mechanisms of the formation of the byproducts and use of KFexo- in catalysis of ICSDPR allowed to develop a highly sensitive plate-based assay of miRNA-141 with the detection limit and sensitivity coefficient of 1.7 fM and 1,400,000 RLU/M, respectively. The amplification index characteristic of KFexo- catalyzed ICSDPR was 22,000. The proposed assay of miRNA-141 showed high specificity toward the target.

Linking triphenylphosphonium cation to a bicyclic hydroquinone improves their antiplatelet effect via the regulation of mitochondrial function

Platelets are the critical target for preventing and treating pathological thrombus formation. However, despite current antiplatelet therapy, cardiovascular mortality remains high, and cardiovascular events continue in prescribed patients. In this study, first results were obtained with ortho-carbonyl hydroquinones as antiplatelet agents; we found that linking triphenylphosphonium cation to a bicyclic ortho-carbonyl hydroquinone moiety by a short alkyl chain significantly improved their antiplatelet effect by affecting the mitochondrial functioning. The mechanism of action involves uncoupling OXPHOS, which leads to an increase in mitochondrial ROS production and a decrease in the mitochondrial membrane potential and OCR. This alteration disrupts the energy production by mitochondrial function necessary for the platelet activation process. These effects are responsive to the complete structure of the compounds and not to isolated parts of the compounds tested. The results obtained in this research can be used as the basis for developing new antiplatelet agents that target mitochondria.

A New Mouse Strain with a Mutation in the NFE2L2 (NRF2) Gene

Transcription factor NRF2 is involved in inflammatory reactions, maintenance of redox balance, metabolism of xenobiotics, and is of particular interest for studying aging. In the present work, the CRISPR/Cas9 genome editing technology was used to generate the NRF2ΔNeh2 mice containing a substitution of eight amino acid residues at the N-terminus of the NRF2 protein, upstream of the functional Neh2 domain, which ensures binding of NRF2 to its inhibitor KEAP1. Heterozygote NRF2wt/ΔNeh2 mice gave birth to homozygous mice with lower than expected frequency, accompanied by their increased embryonic lethality and visual signs of anemia. Mouse embryonic fibroblasts (MEFs) from the NRF2ΔNeh2/ΔNeh2 homozygotes showed impaired resistance to oxidative stress compared to the wild-type MEFs. The tissues of homozygous NRF2ΔNeh2/ΔNeh2 animals had a decreased expression of the NRF2 target genes: NAD(P)H:Quinone oxidoreductase-1 (Nqo1); aldehyde oxidase-1 (Aox1); glutathione-S-transferase A4 (Gsta4); while relative mRNA levels of the monocyte chemoattractant protein 1 (Ccl2), vascular cell adhesion molecule 1 (Vcam1), and chemokine Cxcl8 was increased. Thus, the resulting mutation in the Nfe2l2 gene coding for NRF2, partially impaired function of this transcription factor, expanding our insights into the functional role of the unstructured N-terminus of NRF2. The obtained NRF2ΔNeh2 mouse line can be used as a model object for studying various pathologies associated with oxidative stress and inflammation.

Regulation of mitochondrial function by hydroquinone derivatives as prevention of platelet activation

Platelet activation plays an essential role in the pathogenesis of thrombotic events in different diseases (e.g., cancer, type 2 diabetes, Alzheimer's, and cardiovascular diseases, and even in patients diagnosed with coronavirus disease 2019). Therefore, antiplatelet therapy is essential to reduce thrombus formation. However, the utility of current antiplatelet drugs is limited. Therefore, identifying novel antiplatelet compounds is very important in developing new drugs. In this context, the involvement of mitochondrial function as an efficient energy source required for platelet activation is currently accepted; however, its contribution as an antiplatelet target still has little been exploited. Regarding this, the intramolecular hydrogen bonding of hydroquinone derivatives has been described as a structural motif that allows the reach of small molecules at mitochondria, which can exert antiplatelet activity, among others. In this review, we describe the role of mitochondrial function in platelet activation and how hydroquinone derivatives exert antiplatelet activity through mitochondrial regulation.

Comparison of chemiluminescent heterogeneous and homogeneous–heterogeneous assays coupled with isothermal circular strand-displacement polymerization reaction amplification for the quantification of miRNA-141

A heterogeneous and homogeneous–heterogeneous chemiluminescent microplate assay was developed for the determination of miRNA-141 levels in human cells.

Isothermal chemiluminescent assay based on circular stand-displacement polymerization reaction amplification for cel-miRNA-39-3p determination in cell extracts

A sensitive and specific heterogeneous assay for quantitation of cel-miRNA-39-3p (miRNA-39) was constructed. To improve the assay sensitivity an amplification strategy based on the use of isothermal circular strand-displacement polymerization reaction (ICSDPR), polyperoxidase conjugated with streptavidin and enhanced chemiluminescence was used. The detection limit of the proposed assay was 4 × 10^-13 M. The coefficient of variation (CV) for quantitation of miRNA-39 within the working range was below 8%. The study of cross-reactivity of different miRNAs including miRNA-39 demonstrated high specificity of the proposed assay. Comparison of the calibration curves of miRNA-39 dissolved in the buffer and the lysate of MCF-7 cells (prepared by lysis of the cells with phenol/guanidine thiocyanate mixture and purified using silica membrane spin column) has demonstrated a negligible matrix effect. The proposed assay makes it possible to estimate the yield of purification of miRNAs from cells, which is necessary for the quantitative calculation of the intracellular content of miRNAs measured with the isothermal assay coupled with ICSDPR.