Evaluation of the synergistic potential and mechanisms of action for de novo designed cationic antimicrobial peptides.

Antimicrobial peptides (AMPs) have emerged as promising candidates in combating antimicrobial resistance - a growing issue in healthcare. However, to develop AMPs into effective therapeutics, a thorough analysis and extensive investigations are essential. In this study, we employed an in silico approach to design cationic AMPs de novo, followed by their experimental testing. The antibacterial potential of de novo designed cationic AMPs, along with their synergistic properties in combination with conventional antibiotics was examined. Furthermore, the effects of bacterial inoculum density and metabolic state on the antibacterial activity of AMPs were evaluated. Finally, the impact of several potent AMPs on E. coli cell envelope and genomic DNA integrity was determined. Collectively, this comprehensive analysis provides insights into the unique characteristics of cationic AMPs.

PARP inhibition suppresses topoisomerase 1 poisoning induced Caspase-3 dependent cell death in zebrafish embryos.

In the present study the role of poly(ADP)ribosylation on rubitecan induced caspase dependent cell death was evaluated. We show that Top1 poisoning by rubitecan induces caspase mediated apoptosis which was reduced by PARP inhibitor olaparib in zebrafish embryo. Collectively our data introduces zebrafish as a valuable model for PARP related biomedical research.

Low-dose trans-resveratrol induce poly(ADP)-ribosylation-dependent increase of the PPAR-γ protein expression level in the in vitro model of non-alcoholic fatty liver disease.

An effect of low-dose resveratrol treatment on lipid metabolism and pro-inflammatory processes has been studied, using an in vitro model of Non-Alcoholic-Fatty Liver Disease. The model system consisted of lipid-loaded monolayer cultures of hepatocytes (Hepa1-6) and macrophages (RAW264.7), as both cell types are present in the liver. Also a tridimensional model of hepatic spheroids has been created to mimic spatial adhesive contacts between cells. Treatment with resveratrol (5 µM, 10 µM) for 3 h caused a decrease in lipid load in all three model systems. This decrease wasn't accompanied by any changes in surface expression of lipid transporter-CD36. The response to resveratrol (RSV) was cell type- and cell environment-dependent. In both cell types an increase of the peroxisome proliferator-activated receptor-γ (PPAR-γ) protein level has been revealed. The increase of the PPAR-γ protein level appeared to be poly (ADP)-ribosylation-dependent. It has been revealed, that in the resveratrol-induced signaling pathway, leading to the decrease of intracellular lipid load, an activation of poly (ADP)-ribose polymerase should happen upstream of PPAR-γ protein expression.The decrease of lipid load isn't accompanied by changes in the surface expression of lipid transporter CD36.

Genotoxic effects of topoisomerase poisoning and PARP inhibition on zebrafish embryos.

Topoisomerase poisons are known to stabilize covalent enzyme-DNA intermediates forming covalent cleavage complexes, which are highly cytotoxic especially for dividing cells and thus, make topoisomerases targets for cancer therapy. Topoisomerases have been extensively studied in mammalian model systems, whereas in other vertebrate models including zebrafish, they still remain less characterized. Here we show similarities in the genotoxic effects of zebrafish and mammalian systems towards topoisomerase I (Top1) poisons and PARP inhibitor - olaparib. On the other hand we observed that topoisomerase II (Top2) poisons (doxorubicin and etoposide) did not affect 1 day post fertilization embryo viability, however in cells isolated from Top2 drug treated embryos the formation of DNA cleavage complexes was observed by comet assay. We explain this by cellular drug uptake limitation in live zebrafish embryos versus unimpeded drug influx in cells isolated from Top2 poisons pre-treated embryos. We also demonstrate that EDTA facilitates the extraction of Top2 from zebrafish nuclei and recovers both, basal and Top2 poison induced DNA damage.

Automodification of PARP-1 mediates its tight binding to the nuclear matrix.

Poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme that catalyzes the NAD(+)-dependent addition of ADP-ribose polymers on a variety of nuclear proteins, has been shown to be associated with the nuclear matrix. As yet, the properties and conditions of this association are unclear. Here, we show the existence of two PARP-1 pools associated with the nuclear matrix of rat liver and the ability of PARP-1 automodification to facilitate its binding to the nuclear matrix.