Development of a receptor-targeted gene delivery system using CXCR4 ligand-conjugated cross-linking peptides.

BACKGROUND: Success in gene therapy greatly depends on the efficiency of nucleic acid delivery. Important features of the carriers for gene delivery should include an enhanced transfection ability, targeting of specific receptors and low toxicity. In the present study, we characterized CXCR4-targeted cross-linking peptides modified with an N-terminal fragment of chemokine stromal cell-derived factor-1α as carriers for gene delivery. METHODS: We studied three variants of DNA/carrier complexes with different targeting ligand content. The physicochemical characteristics of the complexes, including their DNA-binding and protective ability, interaction with glycosaminoglycans and size, were determined. Transfection efficacy was studied in cell lines with different levels of CXCR4 expression (HeLa, A172, CHO, Е.А.hy926) and also in human mesenchymal stem cells (hMSCs). The influence of the ligand content on the efficacy of transfection was studied by means of chlorpromazine blockage of clathrin-mediated endocytosis, competition with CXCR4-antagonist AMD3100, and valproic acid treatment of hMSCs. RESULTS: CXCR4-targeted peptides were evaluated for their physicochemical properties and in vitro transfection capacities. Ligand-modified carriers were found to be 10- to 50-fold more effective than unmodified carriers in CXCR4-positive cells. By contrast, their transfection efficacy in CXCR4-negative cells was similar to unmodified carriers. Experiments with chlorpromazine demonstrated receptor-specific transfection in A172 cells. The transfection efficacy of CXCR4-targeted carriers in AMD3100-treated HeLa cells was reduced by two-fold compared to the untreated control. Valproic acid treatment resulted in a four- to 15-fold increase of transfection efficacy for ligand-modified carriers in hMSCs. CONCLUSIONS: CXCR4-targeted cross-linking peptides should be considered as useful tools for nonviral gene delivery into tumor and mesenchymal stem cells.

Pheromone of grouped female mice impairs genome stability in male mice through stress-mediated pathways.

Population density is known to affect the health and survival of many species, and is especially important for social animals. In mice, living in crowded conditions results in the disruption of social interactions, chronic stress, and immune and reproductive suppression; however, the underlying mechanisms remain unclear. Here, we investigated the role of chemosignals in the regulation of mouse physiology and behavior in response to social crowding. The pheromone 2,5-dimethylpyrazine (2,5-DMP), which is released by female mice in crowded conditions, induced aversion, glucocorticoid elevation and, when chronic, resulted in reproductive and immune suppression. 2,5-DMP olfaction induced genome destabilization in bone marrow cells in a stress-dependent manner, providing a plausible mechanism for crowding-induced immune dysfunction. Interestingly, the genome-destabilizing effect of 2,5-DMP was comparable to a potent mouse stressor (immobilization), and both stressors led to correlated expression changes in genes regulating cellular stress response. Thus, our findings demonstrate that, in mice, the health effects of crowding may be explained at least in part by chemosignals and also propose a significant role of stress and genome destabilization in the emergence of crowding effects.

CXCR4-targeted modular peptide carriers for efficient anti-VEGF siRNA delivery.

The application of small interfering RNA (siRNA) for specific gene inhibition is a promising strategy in gene therapy treatments. The efficient cellular delivery of therapeutic siRNA is a critical step in RNA interference (RNAi) application. Highly efficient siRNA carriers should be developed for specific cellular uptake, stable RNA-complexes formation and intracellular RNA release. To study these features, we evaluated modular peptide carriers bearing CXCR4 targeting ligand for their ability to condense siRNA, facilitate endosomal escape and VEGFA gene silencing in CXCR4-expressing endothelial and glioblastoma cells. Peptide carriers were shown to condense and protect siRNA from RNAse degradation. Various N/P ratios were used for physicochemical characterization to optimize siRNA/peptide complexes for in vitro studies. On average, cytotoxicity of siRNA-polyplexes depended on cell type and was not higher than that of PEI/siRNA complexes. VEGFA gene knockdown was significantly improved with CXCR4-targeted carriers in contrast to nontargeted peptides. siRNA delivery by means of ligandconjugated carriers resulted in 2.5-3-fold decrease of VEGF expression in glioblastoma cells and in 1.5-2-fold decrease of VEGF expression in endothelial cells. Delivery of siRNA/peptide complexes resulted in 2-6- fold decrease in VEGF protein yield and in significant inhibition of endothelial cells migration. The study shows that implication of peptide carriers modified with CXCR4 ligand is a promising approach to develop targeted siRNA delivery system into CXCR4-expressing cancer and endothelial cells.

Recent advances in gene therapy of endometriosis.

Endometriosis is a gynecological disease that affects up to 10%-15% of all reproductive-age women worldwide. It is characterized by the presence of endometrial tissues outside the uterine cavity. Endometriosis is a complex disease; its pathogenesis includes altered steroid metabolism and immune system abnormalities such as inflammation, increased angiogenic activity in the peritoneal fluid and impaired recognition of ectopic endometrial cells. The development of endometriosis also depends on genetic, anatomical and environmental factors. Numerous surgical and medical approaches to treat endometriosis have been developed to date. However, complete resolution of the problem has not been achieved so far. Gene therapy holds exciting promise for the treatment of numerous disorders and current studies have indicated it can also be applied to endometriosis. The focus of this review is to summarize the pathogenetic background of the disease and to highlight current gene therapy approaches for this common gynecological disorder.