URRENT CONCEPT OF THE STRUCTURAL AND FUNCTIONAL PROPERTIES OF ALFA-FETOPROTEIN AND THE POSSIBILITIES OF ITS CLINICAL APPLICATION

This paper was aimed to review the literature data from native and foreign sources accumulated for 40-years period of research of the features of the molecular structure, functions, production and application of human alpha-fetoprotein (AFP), which is known as one of the most studied and increasingly demanded proteins. Results of fundamental studies performed with the use of modern methods, including various types of electrophoresis, chromatography, electron microscopy and immunoassay, in order to characterize the principal physicochemical capacities and localization of free and bound forms of AFP, as well as polypeptide structure, heterogeneity and topography of AFP receptors are highlighted here. The data on the mechanisms of AFP synthesis, its conformational features, binding sites and intracellular metabolism are also presented. The concepts of physiological functions and mechanisms of AFP transport in an organism are presented. Data on AFP isolation from the natural primary products and its production by means of recombinant and synthetic methods are shown. This review also summarizes information on the current possibilities of clinical application of AFP and the prospects for its usage in anticancer therapy for targeted delivery of chemotherapy drugs, with emphasis on the description of the recent progress in this field.

The Drosophila Baramicin polypeptide gene protects against fungal infection

The fruit fly Drososphila melanogaster combats microbial infection by producing a battery of effector peptides that are secreted into the haemolymph. The existence of many effectors that redundantly contribute to host defense has hampered their functional characterization. As a consequence, the logic underlying the role of immune effectors is only poorly defined, and exactly how each gene contributes to survival is not well characterized. Here we describe a novel Drosophila antifungal peptide gene that we name Baramicin A. We show that BaraA encodes a precursor protein cleaved into multiple peptides via furin cleavage sites. BaraA is strongly immune-induced in the fat body downstream of the Toll pathway, but also exhibits expression in the nervous system. Importantly, we show that flies lacking BaraA are viable but susceptible to a subset of filamentous fungi. Consistent with BaraA being directly antimicrobial, overexpression of BaraA promotes resistance to fungi and the IM10-like peptides produced by BaraA synergistically inhibit growth of fungi in vitro when combined with a membrane-disrupting antifungal. Surprisingly, BaraA males but not females display an erect wing phenotype upon infection, pointing to an adaptive role for BaraA on the wing muscle or the nervous system. Collectively, we identify a new antifungal immune effector downstream of Toll signalling, improving our knowledge of the Drosophila antimicrobial response.Significance statementAntimicrobial peptides (AMPs) of the innate immune system provide a front line of defence against infection. Recently AMPs have been implicated in physiological processes including inflammation, aging, and neurodegeneration. Drosophila melanogaster has been a useful model for understanding AMP functions and specificities in vivo. Here we describe a new Drosophila AMP family, Baramicin, which protects flies against fungal infection. The Baramicin polypeptide structure is also unique amongst animal AMPs, encoding multiple peptides on a single protein precursor cleaved by furin. Furthermore Baramicin mutants display a behavioural response to infection, suggesting Baramicin AMPs interact with more than just pathogens. Baramicin adds to our knowledge of the potent Drosophila antifungal response, and to growing observations of AMPs acting in seemingly non-canonical roles.

Hirudin Ameliorates Renal Interstitial Fibrosis via Regulating TGF-β1/Smad and NF-κB Signaling in UUO Rat Model

Purpose. Hirudin, a polypeptide structure containing 65 amino acids, is a potent natural thrombin inhibitor with anticoagulant property extracted from Hirudo medicinalis. It has been reported to have anti-inflammatory and antifibrotic property. Here we explored the renoprotective effect of hirudin on unilateral ureteral obstruction (UUO) induced renal interstitial fibrosis (RIF). Methods. Rats were randomly divided into five groups: sham group, UUO alone group, and three UUO + hirudin-treatment groups (10, 20, or 40 IU/kg/d, for 14 continuous days). At the end of the experiment period, animals were sacrificed. Pathologic changes in renal specimens were observed using hematoxylin and eosin (HE) staining and Masson staining. The expressions of collagen III (Col III), fibronectin (FN), α-smooth muscle actin (α-SMA), protease-activated receptor 1 (PAR-1), and proteins in the TGF-β1/Smad and NF-κB pathways in renal tissues were examined by immunohistochemistry and/or Western blotting. Results. HE and Masson staining showed that hirudin-treated UUO rats had lower extent of renal injury and deposition of extracellular matrix (ECM) in renal interstitium than those in the UUO group. The results of immunohistochemistry and WB indicated decreased protein expressions of Col III, FN, α-SMA, PAR-1, and inflammatory markers such as tumor necrosis factor-α and interleukin-6 after hirudin treatment. Furthermore, hirudin reduced the expressions of transforming growth factor β1 (TGF-β1), phosphorylated-Smad2, and phosphorylated-Smad3 in the UUO model. In parallel, we found inhibited nuclear factor-κB (NF-κB) signaling after hirudin treatment, with downregulated protein expressions of P65, phosphorylated-P65, and phosphorylated-iκBα and increased iκBα. Conclusion. Hirudin improves kidney injury and suppresses inflammatory response and ECM accumulation in UUO rats; its underlying mechanism may be associated with the inhibition of TGF-β1/Smad and NF-κB signaling.

Peppy: A Virtual Reality Environment for Exploring the Principles of Polypeptide Structure

ABSTRACTA key learning outcome for undergraduate biochemistry classes is a thorough understanding of the principles of protein structure. Traditional approaches to teaching this material, which include two-dimensional (2D) images on paper, physical molecular modelling kits, and projections of 3D structures into 2D, are unable to fully capture the dynamic, 3D nature of proteins. We have built a virtual reality application, Peppy, aimed at facilitating teaching of the principles of protein secondary structure. Rather than attempt to model molecules with the same fidelity to the underlying physical chemistry as existing, research-oriented molecular modelling approaches, we took the more straightforward approach of harnessing the Unity video game physics engine. Indeed, the simplicity and limitations of our model are a strength in a teaching context, provoking questions and thus deeper understanding. Peppy allows exploration of the relative effects of hydrogen bonding (and electrostatic interactions more generally), backbone ϕ/ψ angles, basic chemical structure and steric effects on polypeptide structure in an accessible format that is novel, dynamic and fun to use. As well as describing the implementation and use of Peppy, we discuss the outcomes of deploying Peppy in undergraduate biochemistry courses.STATEMENTProtein structure is inherently dynamic and three-dimensional, but traditional teaching tools are static and/or two-dimensional. We have developed a virtual reality teaching tool, Peppy, that facilitates undergraduate teaching of the principles of protein structure. We outline how Peppy works in terms of how it is used and what goes on ‘under the hood’. We then illustrate its use in undergraduate teaching, where its playful nature stimulated exploration and, thus, deeper understanding.

Transcriptome-wide sites of collided ribosomes reveal principles of translational pausing

Translation initiation is the major regulatory step defining the rate of protein production from an mRNA. Meanwhile, the impact of non-uniform ribosomal elongation rates is largely unknown. Using a modified ribosome profiling protocol based on footprints from two closely packed ribosomes (disomes), we have mapped ribosomal collisions transcriptome-wide in mouse liver. We uncover that the stacking of an elongating onto a paused ribosome occurs frequently and scales with translation rate, trapping ∼10% of translating ribosomes in the disome state. A distinct class of pause sites, independent of translation rate, is indicative of deterministic pausing signals. Pause site association with specific amino acids, peptide motifs and nascent polypeptide structure, is suggestive of programmed pausing as a widespread mechanism associated with protein folding. Evolutionary conservation at disome sites indicates functional relevance of translational pausing. Collectively, our disome profiling approach allows unique insights into gene regulation occurring at the step of translation elongation.

Diagnostic performance of heart-type fatty acid binding protein and high sensitive-cardiac troponin in patients in an emergency department sus-pected of acute myocardial infarction

Heart-type fatty acid binding protein (H-FABP) also referred to as mammary­ derived growth inhibitor is a polypeptide structure that in humans transcribed by FABP3 gene. It is preferred to be investigated in combination with troponin to the diagnosis of myocardial infarction in patients suffering from chest pain. This study aims to evaluate the role of H­ FABP in early diagnosis of MI in comparison with new generation cardiac troponin (hs-c'Tn) and to differentiate patients with ischemic chest pain from non-ischemic ones. This case-control study was performed at the Department of Biochemistry, Medical school, University of Baghdad, during the period from December 2017 to August 2018. It involved 36 patients presented with chest pain; 18 ischemic patients (AMI) and 18 non- ischemic patients (non-AMI) who served as pathological control. Serum investigations included measurements of FABP and hs-c'I'n using enzyme-linked immunosorbent assay (ELISA) method. The mean (±SD) value of serum FABP levels at 1-3 hours did not differ significantly between ischemic and non- ischemic subjects, while it was significantly increased at 6-9 hours in ischemic patients (p< 0.001). However, the mean value of serum levels of hs-c'I'n was significantly higher in AMI patients than in non- AMI ones at 1-3 hours (p<O.0. 04) and 6-9 hours (u<O.o. m). The results concluded that serum hs-c'Tn still the best biochemical marker in confirming the diagnosis of early acute MI and is superior of H-FABP in the rule in and rule out of MI.

Novel Formulations of C-Peptide with Long-Acting Therapeutic Potential for Treatment of Diabetic Complications

The development and application of novel nanospheres based on cationic and anionic random amphiphilic polypeptides with prolonged stability were proposed. The random copolymers, e.g., poly(l-lysine-co-d-phenylalanine) (P(Lys-co-dPhe)) and poly(l-glutamic acid-co-d-phenylalanine) (P(Glu-co-dPhe)), with different amount of hydrophilic and hydrophobic monomers were synthesized. The polypeptides obtained were able to self-assemble into nanospheres. Such characteristics as size, PDI and ζ-potential of the nanospheres were determined, as well as their dependence on pH was also studied. Additionally, the investigation of their biodegradability and cytotoxicity was performed. The prolonged stability of nanospheres was achieved via introduction of d-amino acids into the polypeptide structure. The cytotoxicity of nanospheres obtained was tested using HEK-293 cells. It was proved that no cytotoxicity up to the concentration of 500 µg/mL was observed. C-peptide delivery systems were realized in two ways: (1) peptide immobilization on the surface of P(Glu-co-dPhe) nanospheres; and (2) peptide encapsulation into P(Lys-co-dPhe) systems. The immobilization capacity and the dependence of C-peptide encapsulation efficiency, as well as maximal loading capacity, on initial drug concentration was studied. The kinetic of drug release was studied at model physiological conditions. Novel formulations of a long-acting C-peptide exhibited their effect ex vivo by increasing activity of erythrocyte Na+/K+-adenosine triphosphatase.