Barnase*Barstar-guided two-step targeting approach for drug delivery to tumor cells in vivo.

For precise ligation of a targeting and cytotoxic moiety, the use of Barnase-Barstar pair as a molecular glue is proposed for the first time. Targeting was mediated through the use of a scaffold protein DARPin_9-29 specific for the human epidermal receptor 2 (HER2) antigen that is highly expressed on some types of cancer and Barnase*Barstar native bacterial proteins interacted with each other with Kd 10-14 M. The approach proposed consists of prelabeling a target tumor with hybrid protein DARPin-Barnase prior to administration of cytotoxic component-loaded liposomes that have Barstar covalently attached to their surface. Based on in vivo bioimaging we have proven that DARPin-based Barnase*Barstar-mediated pretargeting possesses precise tumor-targeting capability as well as antitumor activity leading to apparent tumor-growth inhibition of primary tumors and distant metastases in experimental animals. The results obtained indicate that the new system combining DARPin and Barnase*Barstar can be useful both for the drug development and for monitoring the response to treatment in vivo in preclinical studies.

Morphofunctional Changes in Colon after Cold Stress in Male C57BL/6 Mice Susceptible and Tolerant to Hypoxia.

There are individual differences in the tolerance to hypoxia and stress. Stress can contribute to the development of various diseases, including inflammatory bowel disease. It was found that inflammatory bowel diseases in animals susceptible to hypoxia runs more severe course than in tolerant animals. We studied morphofunctional changes in the colon under conditions of modeled cold stress in male C57BL/6 mice susceptible and tolerant to hypoxia. The animals were daily subjected to cold stress (20 min at -20°C) for 2 weeks. Cold stress was followed by an increase in the volume fraction of goblet cells in the colon and production of mucins by these cells in mice tolerant to hypoxia and an increase in cell content in the lamina propria of the colon mucous membrane in animals susceptible to hypoxia. The number of serotoninproducing endocrine cells increased in both groups, but these changes were more pronounced in mice susceptible to hypoxia.

[Vaccination with virus-like particles containing hemagglutinin protects the lungs of mice with postifluenza bacterial pneumonia: virological, microbiological and clinical data].

INTRODUCTION: Influenza is a severe viral disease, a frequent complication of which is a secondary bacterial pneumonia. Influenza vaccines prevent secondary bacterial complications. Virus-like particles are one of the promising areas for the development of new vaccines. The aim of this work is to study the correlation of the pathomorphological characteristics of the lungs with clinical, virological, and microbiological markers of the disease at vaccination with virus-like particles (VLPs), containing hemagglutinin (HA) of influenza virus (HA-Gag-VLPs) in a murine model of secondary bacterial pneumonia induced by S. pneumoniae after influenza infection. MATERIAL AND METHODS: BALB/c mice were vaccinated with VLPs containing influenza HA. After 21 days, mice were infected with two strains of influenza viruses, homologous and non-homologous, and 5 days after viral infection, were infected with S. pneumoniae. The vaccination effect was evaluated by morphological, virological (titer of the virus in the lungs) and microbiological (titer of bacteria in the lungs) data, and was confirmed by clinical data (survival, change in body weight). RESULTS: Immunization with HA-Gag-VLPs, followed by infection with a homologous influenza virus and S. pneumoniae, reduced the area of foci of inflammation, inhibited the replication of the virus and bacteria in the lungs, and also protected animals from death and reduced their weight loss. Immunization with HA-Gag-VLPs upon infection with a heterologous strain and S. pneumoniae did not affect these criteria. CONCLUSION: The immunization with HA-Gag-VLPs prevented the viral replication, providing a reduction of S. pneumoniae titer and the degree of lung damage, protecting animals from the disease in a murine model of secondary bacterial pneumonia, induced by S. pneumoniae, after influenza infection with homologous strain of the virus.

Expression of Hif-1α, Nf-κb, and Vegf Genes in the Liver and Blood Serum Levels of HIF-1α, Erythropoietin, VEGF, TGF-ß, 8-Isoprostane, and Corticosterone in Wistar Rats with High and Low Resistance to Hypoxia.

We studied the expression of Hif-1α, Nf-κb, and Vegf genes in the liver and serum levels of HIF-1α, erythropoietin, VEGF, TGF-ß, 8-isoprostane, and corticosterone in Wistar rats with different resistance to hypoxia in 5 and 90 min after acute exposure to hypobaric hypoxia. In 5 min after hypoxic exposure, Hif-1α expression in the liver and serum levels of erythropoietin, VEGF, and TGF-ß in high-resistant rats were higher than in low-resistant animals. In highresistant rats, the increment in expression of Nf-κb gene responsible for the control over the inflammatory processes was more pronounced than in low-resistant animals. In 90 min after hypoxic exposure, the serum levels of HIF-1α, erythropoietin, VEGF, and TGF-ß returned to normal in high-resistant rats, while in low-resistant animals, an increase in 8-isoprostane and TGF-ß concentrations was observed. The rats with different resistance to hypoxia were characterized by different changes in biomolecular parameters determining predilection to inflammatory diseases.