Interplay between SARS-CoV-2-derived miRNAs, immune system, vitamin D pathway and respiratory system.

The new coronavirus pandemic started in China in 2019. The intensity of the disease can range from mild to severe, leading to death in many cases. Despite extensive research in this area, the exact molecular nature of virus is not fully recognized; however, according to pieces of evidence, one of the mechanisms of virus pathogenesis is through the function of viral miRNAs. So, we hypothesized that SARS-CoV-2 pathogenesis may be due to targeting important genes in the host with its miRNAs, which involved in the respiratory system, immune pathways and vitamin D pathways, thus possibly contributing to disease progression and virus survival. Potential miRNA precursors and mature miRNA were predicted and confirmed based on the virus genome. The next step was to predict and identify their target genes and perform functional enrichment analysis to recognize the biological processes connected with these genes in the three pathways mentioned above through several comprehensive databases. Finally, cis-acting regulatory elements in 5' regulatory regions were analysed, and the analysis of available RNAseq data determined the expression level of genes. We revealed that thirty-nine mature miRNAs could theoretically derive from the SARS-CoV-2 genome. Functional enrichment analysis elucidated three highlighted pathways involved in SARS-CoV-2 pathogenesis: vitamin D, immune system and respiratory system. Our finding highlighted genes' involvement in three crucial molecular pathways and may help develop new therapeutic targets related to SARS-CoV-2.

Decreasing the immunogenicity of Erwinia chrysanthemi asparaginase via protein engineering: computational approach.

Immunogenicity of therapeutic proteins is one of the main challenges in disease treatment. L-Asparaginase is an important enzyme in cancer treatment which sometimes leads to undesirable side effects such as immunogenic or allergic responses. Here, to decrease Erwinase (Erwinia chrysanthemiL-Asparaginase) immunogenicity, which is the main drawback of the enzyme, firstly conformational B cell epitopes of Erwinase were predicted from three-dimensional structure by three different computational methods. A few residues were defined as candidates for reducing immunogenicity of the protein by point mutation. In addition to immunogenicity and hydrophobicity, stability and binding energy of mutants were also analyzed computationally. In order to evaluate the stability of the best mutant, molecular dynamics simulation was performed. Among mutants, H240A and Q239A presented significant reduction in immunogenicity. In contrast, the immunogenicity scores of D235A slightly decreased according to two servers. Binding affinity of substrate to the active site reduced significantly in K265A and E268A. The final results of molecular dynamics simulation indicated that H240A mutation has not changed the stability, flexibility, and the total structure of desired protein. Overall, point mutation can be used for reducing immunogenicity of therapeutic proteins, in this context, in silico approaches can be used to screen suitable mutants.

Therapeutic Enzymes: Applications and Approaches to Pharmacological Improvement.

BACKGROUND: Among therapeutic proteins, enzymes represent small and of course profitable market. They can be used to treat important, rare, and deadly diseases. Enzyme therapy is the only available treatment for certain disorders. METHOD: Here, pharmaceutical enzymes are reviewed. They are categorized in four main groups, enzymes in replacement therapy, enzymes in cancer treatment, enzymes for fibrinolysis, and finally enzymes that are used topically for various treatments. Furthermore, enzyme gene therapy and future perspective of therapeutic enzymes are mentioned in brief. RESULTS: There are many important approved enzymes in pharmaceutical market. Several approaches such as point mutation, fusion protein designing, glycoengineering, and PEGylation were used to achieve improved enzymes. Although sometimes enzymes were engineered to facilitate production and purification process, appropriate delivery to target sites, extending half-life, and reducing immunogenicity are among the main goals of engineering approaches. CONCLUSION: Overall, enzymes play a critical role in treatment of common and rare diseases. Evaluation of new enzymes as well as improvement of approved enzymes are of the most important challenges in biotechnology.

Staphylokinase Enzyme: An Overview of Structure, Function and Engineered Forms.

BACKGROUND: One of the most important causes of death in the modern lifestyle is acute ischemic stroke, which is related to thrombosis in the blood vessels. Staphylokinase (SAK), a fibrinolytic agent, which is produced mainly by Staphylococcus aureus, is an indirect activator of plasminogen and belongs to the third generation of fibrinolytic enzymes. METHODS: Considering the very low level of production and immunogenicity concerns of natural SAK produced by Staphylococcus aureus, attempts have been made to produce recombinant SAKs with high production levels, more fibrinolytic activities and low immunogenicity. RESULTS AND CONCLUSION: In this review, we summarized a number of expression systems based on recombinant DNA technology and protein-engineering approaches, which have been developed for the production of engineered recombinant SAK molecules with higher fibrinolytic activities and lower antigenicity.

Ascorbic acid antagonizes nicotine-induced place preference and behavioral sensitization in mice.

In the present study, the influence of ascorbic acid on the nicotine-induced behavioral sensitization and conditioned place preference was investigated in mice. In the place preference paradigm, intraperitoneal (i.p.) nicotine (1 and 1.5 mg/kg, three drug sessions) but not ascorbic acid (1, 10, 100 and 1000 mg/kg) administration induced place preference. Ascorbic acid administration (10, 100 and 1000 mg/kg, i.p.) reduced both the acquisition and expression of nicotine-induced place conditioning. Locomotor sensitization in mice was produced by intraperitoneal injection of nicotine (0.25 mg/kg) for 7 consecutive days. On the 9th day of the experiments, activity of the mice was recorded after challenge with nicotine (0.1 mg/kg, i.p.). Ascorbic acid (10, 100 and 1000 mg/kg, i.p.) was injected 20 min before each injection of nicotine (acquisition of sensitization) or acutely 20 min before a challenge nicotine injection (expression of sensitization). It was shown that ascorbic acid attenuated the acquisition of nicotine sensitization in a dose-independent manner but the expression of nicotine-induced sensitization was not affected by ascorbic acid. In conclusion, it seems that ascorbic acid may interfere with nicotine-induced place preference and behavioral sensitization in mice.