Instytut Biotechnologii i Antybiotyków

Abstract Proteases encoded by SARS-CoV-2 constitute a promising target for new therapies against COVID-19. SARS-CoV-2 main protease (M pro , 3CL pro ) and papain-like protease (PL pro ) are responsible for viral polyprotein cleavage - a process crucial for viral survival and replication. Recently it was shown that 2-phenylbenzisoselenazol-3(2H)-one (ebselen), an organoselenium anti-inflammatory small-molecule drug, is a potent, covalent inhibitor of both the proteases and its potency was evaluated in enzymatic and anti-viral assays. In this study, we screened a collection of 23 ebselen derivatives for SARS-CoV-2 PL pro and M pro inhibitors. Our studies revealed that ebselen derivatives are potent inhibitors of both the proteases. We identified three PL pro and four M pro inhibitors superior to ebselen. Our work shows that ebselen constitutes a promising platform for development of new antiviral agents targeting both SARS-CoV-2 PL pro and M pro .

IntroductionCytokines are important immune modulator factors controlling homeostasis of the body and are involved in tissue regeneration after wound healing. The encapsulation of cytokines in liposomes has many advantages potentially useful for their transfer to the cells. Liposomes protect cytokines from neutralization, improving their pharmacokinetics or biologic activity in vivo. They are targeted to specific cell types and may delay the release of cytokines, allowing their sustained paracrine delivery. Their physicochemical characteristics such as size, shape, charge, and stability are important parameters improving bio-distribution and prolonged pharmacokinetics of encapsulated cytokines.Material and methodsWe developed an efficient protocol for the encapsulation of two types of cytokines, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), in liposomes that can be stored long term in the active state.ResultsThis method allows for the encapsulation of 12–13% of the total amount of cytokines and 50% of encapsulated cytokines are entrapped in liposomes of more than ≤ 600 nm in diameter. We show that in the studied cell lines the liposome-encapsulated cytokines do not affect cell morphology, proliferation or mortality.ConclusionsThe G-CSF or GM-CSF can be delivered to the cells in working concentrations through the encapsulation in the liposomes. Before the clinical application, the efficiency of these liposomes should be confirmed by an in vivo study.

Herein, the monoalkylation of anilines with trichloroacetimidates catalyzed by CSA was investigated theoretically, and it was found that the reaction occurred through an SN1 reaction involving the dual hydrogen-bonding activation modes.

The published data indicate that the bacterium Clavibacter michiganensis subsp. sepedonicus (Cms) shows a notably low degree of intraspecific variation, and most of the molecular diagnostic methods could differentiate among subspecies groups but lacked the resolution to detect genetic diversity within subspecies. The present study describes effective differentiation of 50 isolates of C. michiganensis subsp. sepedonicus by the PCR MP method using five restriction enzymes (ApaI, PstI, BamHI, XmaI, HindIII). By analysing the electrophoretic patterns obtained by the PCR MP method performed with the applied restriction enzymes, each of the 50 tested isolates could be identified and distinguished from the remaining isolates. The PCR MP method of bacterial strain identification can be used in epidemiological studies, particularly for excluding the isolates of C. michiganensis subsp. sepedonicus as a source of primary infection.

Escherichia coli is one of the most widely used hosts for the production of heterologous proteins. Within this host, the choice of cloning vector constitutes a key factor for a satisfactory amplified expression of a target gene. We aimed to develop novel, unpatented expression vectors that enable the stable maintenance and efficient overproduction of proteins in E. coli. A series of expression vectors based on the ColE1-like pIGDM1 plasmid were constructed. The vectors named pIGDMCT7RS, pIGDM4RS and pIGDMKAN carry various antibiotic resistance genes: chloramphenicol, ampicillin or kanamycin, respectively. Two derivatives contain the inducible T7 promoter while the third one bears the constitutive pms promoter from a clinical strain of Klebsiella pneumoniae. The pIGDM1-derivatives are compatible with other ColE1-like plasmids commonly used in molecular cloning. The pIGDMCT7RS and pIGDM4RS vectors contain genes encoding AGA and AGG tRNAs, which supplement the shortage of these tRNAs, increasing the efficiency of synthesis of heterologous proteins. In conclusion, pIGDMCT7RS, pIGDM4RS and pIGDMKAN vectors, with significantly improved features, including compatibility with vast majority of other plasmids, were designed and constructed. They enable a high-level expression of a desired recombinant gene and therefore constitute a potential, valuable tool for pharmaceutical companies and research laboratories for their own research or for the production of recombinant biopharmaceuticals.

H1N1 influenza virus is still regarded as a serious pandemic threat. The most effective method of protection against influenza virus and the way to reduce the risk of epidemic or pandemic spread is vaccination. Influenza vaccine manufactured in a traditional way, though well developed, has some drawbacks and limitations which have stimulated interest in developing alternative approaches. In this study, we demonstrate that the recombinant H1 vaccine based on the hydrophilic haemagglutinin (HA) domain and produced in the yeast system elicited high titres of serum haemagglutination-inhibiting antibodies in mice. Transmission electron microscopy showed that H1 antigen oligomerizes into functional higher molecular forms similar to rosette-like structures. Analysis of the N-linked glycans using mass spectrometry revealed that the H1 protein is glycosylated at the same sites as the native HA. The recombinant antigen was secreted into a culture medium reaching approximately 10 mg/l. These results suggest that H1 produced in Pichia pastoris can be considered as the vaccine candidate against H1N1 virus.

Genistein (plant isoflavone) is a well-known anti-cancer drug with estrogenic-like properties. Genistein also regulates sugar and lipid metabolism; thus, it has anti-diabetic properties. The aim of the study was to evaluate in vitro effects of genistein on glucose transport, fatty acids oxidation, activation of PKB, and expression of genes related to insulin pathway in differentiated myoblast C2C12 mouse cell line. Differentiated myoblast C2C12 mouse cell line was used to assess the effects of different genistein concentrations on glucose transport and fatty acids oxidation measured by radioactivity technique, activation of PKB, and expression of selected genes related to insulin signaling pathway (IR-a, IR-b, IRS-1, PKB, GLUT-4, PP2A, SH-PTP2) at the mRNA and protein levels. Cells were incubated with various concentrations of genistein under standard conditions for 0-48 hours. Genistein in low concentrations (0.1-1 μM) significantly increased glucose transport and decreased fatty acids oxidation in C2C12 cells after 48 h of incubation. High concentration of genistein (50 μM) had the opposite effect. Genistein stimulated PKB phosphorylation during the first 5-10 minutes of incubation. There was no significant impact on the protein expression of selected genes (IR-a, IR-b, IRS-1, PKB, GLUT-4, PP2A-Ca, ER-a and ER-b) after 48 h treatment. We observed inverse correlation between genistein concentration and the expression of SH-PTP2 protein. Genistein affected the expression pattern of mRNAs for genes related to the insulin pathway, however, not the expression of the encoded proteins. The results of this study showed that depending on the concentration and time of incubation genistein significantly affects glucose and lipid metabolism and at low concentration modifies expression pattern of a few genes in C2C12 cells.

Factor VIII (FVIII), an essential blood coagulation protein, is a key component of the fluid phase blood coagulation system. Human factor VIII is a single chain of about 300 kDa consisting of domains described as A1-A2-B-A3-C1-C2. The protein undergoes processing prior to secretion into blood resulting in a heavy chain of 200 kDa (A1-A2-B) and a light chain of 80 kDa (A3-C1-C2) linked by metal ions. The role of factor VIII is to increase the catalytic efficiency of factor IXa in the activation of factor X. Variants of these factors lead frequently also to severe bleeding disorders.

Our research aimed to compare the effects of four cryoprotectants and four slow freezing programs on the viability and apoptosis of primordial germ cells (PGCs) in vitro. PGCs were collected from chicken embryonic blood at Hamburger and Hamilton (HH) stages 14-16 and purified by Percoll density gradient centrifugation and then subjected to cryopreservation. We applied microscopy to determine the survival of PGCs after trypan blue staining and flow cytometry to examine apoptosis and viability after annexin V kit staining. We also examined the functionality of cryopreserved PGCs in vivo. Significant differences in viability of PGCs determined via microscopy and flow cytometry were observed. The most unfavorable combination for slow freezing PGCs was program 3 and MIX H (10% DMSO and 5% glycerol in Hank's solution supplemented with 10% FBS) as the cryoprotectant (48.43 and 15.37% live and early apoptotic PGCs, respectively). The highest average percentage of live PGCs (93.1%) and the lowest percentage of early apoptotic PGCs (6.5%) were achieved by slow freezing PGCs in the presence of DMSO F (10% DMSO in FBS) via program 1. Therefore, this method was chosen for the in vivo test. Cryopreserved (group 1) and freshly isolated (group 2) PGCs were transfectedwith a pEGFP-N1 plasmid, cultured under antibiotic selection, and then injected into 3-day-old embryos. After 5 days of incubation, we identified the EGFP marker gene in the gonads of 40 and 45% of recipients in groups 1 and 2, respectively. This is the first study to apply flow cytometry to examine the apoptosis and viability of cryopreserved PGCs. The in vitro and in vivo findings showed that the developed PGC cryoconservation method, depending on slow freezing at the rate of 2°C/min (program 1) in the presence of 10% DMSO F, is an improvement over previous cryoconservation methods and may be a useful tool for the ex situ strategy of poultry biodiversity preservation.