[Serum of Mice Immunized with Mt1-MMP Metalloproteinase Reduces Migration Potential of Pancreatic Cancer Cells].

Expression levels of matrix metalloproteinases, in particular MT1-MMP, are elevated in pancreatic cancer (PC) cells, and this is associated with increased tumor proliferation, invasion, and migration. MT1-MMP is considered a promising target for drug therapy of PC, but the use of inhibitors and therapeutic antibodies to MT1-MMP is limited because maximal efficiency is only observed in a narrow time interval, at the early asymptomatic stages of the disease. This problem could be solved by immunization to MPs at the moment of detection of the primary tumor. This therapeutic effect could be provided by specific antibodies that can be re-produced in case of relapses. Here, we selected the optimal mode for immunization of mice with MT1-MMP fragments that allows us to obtain a high titer of specific antibodies in the blood serum. The obtained antiserums effectively inhibited MT1-MMP enzymatic activity, migration of PANC-02 PC cells through the collagen matrix, and activation of the main inducers of epithelial -mesenchymal transition, TGF-ß and MMP-2. These results maybe useful in the development of drugs for PC treatment, and the approach we propose might form the basis for design of antitumor drugs with prolonged action.

[Clinical portrait of a patient with COVID-19. The experience of a multidisciplinary clinic].

AIM: Evaluation of the clinical characteristics in patients with COVID-19. MATERIALS AND METHODS: The article presents clinical and instrumental data of 1169 patients included in a single-center mixed study. Patients were tested for COVID-19 using polymerase chain reaction, computed tomography (CT), and antibody screening. Clinical history data were collected. RESULTS: In patients with confirmed COVID-19, lung damage and a positive test for antibodies were observed in 75.5 and 45.2% of cases, respectively. The most common symptoms of COVID-19 were: fever (73.2%), weakness, (72.7%) dry cough (62.8%) and shortness of breath (55.4%). Patients with CT-visualized lung lesions were more likely to have clinical symptoms and elevated levels of antibodies. Patients with chronic diseases of the endocrine system, circulatory system, and respiratory system had a more severe course of the disease (CT-14: 91.296.3%) than patients without chronic diseases (CT-14: 85,1%). CONCLUSION: We have compiled a clinical profile of patients with COVID-19 and highlighted the most significant clinical characteristics corresponding to a more severe course of the disease. Our data showed that patients with chronic diseases require a personalized approach and the development of specific criteria for the diagnosis and treatment of COVID-19.

Near-Infrared Fluorescent Proteins and Their Applications.

High transparency, low light-scattering, and low autofluorescence of mammalian tissues in the near-infrared (NIR) spectral range (~650-900 nm) open a possibility for in vivo imaging of biological processes at the micro- and macroscales to address basic and applied problems in biology and biomedicine. Recently, probes that absorb and fluoresce in the NIR optical range have been engineered using bacterial phytochromes - natural NIR light-absorbing photoreceptors that regulate metabolism in bacteria. Since the chromophore in all these proteins is biliverdin, a natural product of heme catabolism in mammalian cells, they can be used as genetically encoded fluorescent probes, similarly to GFP-like fluorescent proteins. In this review, we discuss photophysical and biochemical properties of NIR fluorescent proteins, reporters, and biosensors and analyze their characteristics required for expression of these molecules in mammalian cells. Structural features and molecular engineering of NIR fluorescent probes are discussed. Applications of NIR fluorescent proteins and biosensors for studies of molecular processes in cells, as well as for tissue and organ visualization in whole-body imaging in vivo, are described. We specifically focus on the use of NIR fluorescent probes in advanced imaging technologies that combine fluorescence and bioluminescence methods with photoacoustic tomography.

DEVELOPMENT OF SINGLE-DOMAIN NEAR-INFRARED FLUORESCENT PROTEIN GAF-FP BASED ON BACTERIAL PHYTOCHROME.

Fluorescent proteins (FPs) are widely used as genetically encoded markers for noninvasive and quantitative study of biological processes. Development of biomarkers that fluoresce in the near-infrared spectral range allows the study of animals at a deeper level due to high permeability of tissues to light in this wavelength range, compared to the visible light. For widespread use of FPs, such properties as low molecular weight and the monomer become important. In this paper, we developed a FP called the GAF-FP and based on the chromophore- binding domain of bacterial phytochrome from Rhodopseudomonas palustris (RpBphP1). GAF-FP has a molecular mass of ~ 19 kDa, 2 times lower than that of other FP based on BphPs and 1.4 times less than the commonly used GFP-like proteins. Unlike most other near-infrared FP, GAF-FP is a monomer, has high photostability and its structure can withstand the introduction of small peptide inserts. Moreover, GAF-FP can covalently bind two different tetrapyrrole chromophores: phycocyanobilin (PCB) and biliverdin (BV), which is found in mammalian tissues. GAF-FP with BV as a chromophore (GAF-FP­BV) has a main absorption band with a maximum at 635 nm and fluorescence maximum at 670 nm, whereby GAF-FP has a high signal to background ratio even if localized at a depth of several mm below the tissue surface. Apart from the near-infrared absorption band, GAF-FP­BV also has also an absorption band in the violet spectral range with a maximum at 378 nm. This property has been used by us to create a chimeric protein consisting of a modified luciferase from Renilla reniformis (RLuc8) and GAF-FP. We have shown that the chimeric protein is capable of resonance energy transfer from the substrate, which is oxidized by luciferase, to chromophore of GAF-FP­BV. In the absence of energy acceptor, RLuc8 catalyzes the cleavage of the substrate with light radiation having a peak of 400 nm. At the same time, as a part of GAF-FP­RLuc8 chimeric protein, the energy from the substrate is transferred to the chromophore of FP and then emitted in the near-infrared spectral range corresponding to GAF-FP fluorescence. These results open the way for the creation of new small near-infrared FPs based on various natural BphPs with a prospect of their wider use in cell and molecular biology.