Recombinant Polypeptide Research Articles

Recombinant Supercharged Polypeptide Fusions for the Hydrophilic Finishing of PET Textiles

Recombinant Supercharged Polypeptide Fusions for the Hydrophilic Finishing of PET Textiles

Recombinant human FOXJ1 Protein Binds DNA, Forms Higher-Order Oligomers, Has Gel-Shifting Domains and Contains Intrinsically Disordered Regions.

Forkhead box protein J1 (FOXJ1) is the key transcriptional regulator during the conversion of mammalian primary cilia with a 9+0 architecture to the motile (9+2) one. The nucleotide sequences of the full-length and DNA-binding domain (DBD) of the open reading frame (ORF) were isolated and expressed into E. coli as 6xHis-tagged proteins. Upon induction, the DBD formed inclusion bodies that solubilized with 8 M urea. No induction of 6xHis-FOXJ1 protein was seen despite sub-cloning into several expression vectors and E. coli host strains. To improve induction and solubility, the 6xHis tag was substituted with Glutathione S-transferase (GST), and weak induction was seen in E. coli BL21(DE3). The GST-FOXJ1 showed anomalous migration on denaturing gel electrophoresis (AM-DRE)., migrating at approximately 83 kDa instead of its calculated molecular weight (Mr) of 72.4 kDa. It was also unstable and led to degradation products. The 6xHis tag was substituted with Glutathione S-transferase (GST) to improve induction and solubility Codon-optimization improved the induction, but the protein still showed AM-DRE and instability. It seemed that the recombinant protein was either toxic or posed a metabolic burden to the E. coli cells or, once produced was prone to degradation due mainly to the lack of post-translational modification (PTM). This process is required for some eukaryotic proteins after they are manufactured in the ribosomal factory. Both the purified recombinant proteins exhibited cysteine-induced oligomerization via the formation of disulphide bridges since this was reduced using dithiothreitol (DTT). Both were equally functional as these individually bound to an oligonucleotide, a consensus DNA-binding sequence for FOX proteins. Further, the recombinant polypeptides corresponding to the C-terminus and N-terminus show anomalies indicating that the highly acidic residues (known as polyacidic gel-shifting domains) in these polypeptides contribute to the AM-DRE. We demonstrate for the first time that the recombinant HsFOXJ1 and its DBD bind to DNA, its polyacidic gel-shifting domains are the reason for the AM-DRE, is unstable leading to degradation products, exhibits cysteine-induced oligomerization and harbours intrinsically disordered regions.

Molecular Characterization of Ancient Prosaposin-like Proteins from the Protist Dictyostelium discoideum.

To combat the permanent exposure to potential pathogens every organism relies on an immune system. Important factors in innate immunity are antimicrobial peptides (AMPs) that are structurally highly diverse. Some AMPs are known to belong to the saposin-like proteins (SAPLIPs), a group of polypeptides with a broad functional spectrum. The model organism Dictyostelium discoideum possesses a remarkably large arsenal of potential SAPLIPs, which are termed amoebapore-like peptides (Apls), but the knowledge about these proteins is very limited. Here, we report about the biochemical characterization of AplE1, AplE2, AplK1, and AplK2, which are derived from the two precursor proteins AplE and AplK, thereby resembling prosaposins of vertebrates. We produced these Apls as recombinant polypeptides in Escherichia coli using a self-splicing intein to remove an affinity tag used for purification. All recombinant Apls exhibited pore-forming activity in a pH-dependent manner, as evidenced by liposome depolarization, showing higher activities the more acidic the setting was. Lipid preference was detected for negatively charged phospholipids and in particular for cardiolipin. Antimicrobial activity against various bacteria was found to be inferior in classical microdilution assays. However, all of the Apls studied permeabilized the cytoplasmic membrane of live Bacillus subtilis. Collectively, we assume that the selected Apls interact by their cationic charge with negatively charged bacterial membranes in acidic environments such as phagolysosomes and eventually lyse the target cells by pore formation.

Preclinical Development of a Genetically Engineered Albumin‐Binding Nanoparticle of Paclitaxel

Nab‐paclitaxel (Abraxane), an albumin‐bound solvent‐free paclitaxel (PTX) formulation that takes advantage of the endogenous albumin transport pathway, is the current gold standard for treatment of solid tumors with PTX. However, nab‐paclitaxel has several limitations, including complex manufacturing, immunogenicity, slow drug‐release, and a narrow therapeutic window. Nevertheless, no other PTX formulation has gained the Food and Drug Administration approval since Abraxane's 18‐year reign. Addressing these concerns, herein, a PTX‐loaded nanoparticle of a recombinant polypeptide that—like nab‐paclitaxel—capitalizes on the long in vivo half‐life of albumin is reported. This genetically engineered nanoparticle packages PTX in the core of the nanoparticle and displays an albumin‐binding domain on the exterior of the nanoparticle. Upon in vivo administration, the drug‐loaded nanoparticle binds albumin with nanomolar affinity, and acquires an albumin‐corona, which eliminates the need to use exogenous albumin. The nanoparticles can be stored at subzero temperature as lyophilized powder without any cryoprotectants for upto a year and can be reconstituted on‐demand in aqueous buffer at high concentration, thus greatly simplifying formulation processes. These albumin‐binding nanoparticles improve the therapeutic window by at least twofold compared to nonalbumin‐binding counterpart and outperform nab‐paclitaxel in multiple murine tumor models, results that have been independently replicated by a contract research organization.

Experimentally investigated “CoronaDerm-PS”-driven SARS-CoV-2-specific cellular immunity and safety

Novel coronavirus disease 2019, caused by the SARS-CoV-2, initiate humoral and cellular immune responses against diverse virus antigens. The assessment of SARS-CoV-2-specific is mainly carried out in routine practice by determining specific immunoglobulins. However, high variability in S-protein structure in new genovariants of SARS-CoV-2 virus and the lack of correlation between specific antibodies and CD8+ T-lymphocytes underlie false negative responses, and mass assessment of cellular immunity is complicated due to the complexity of applying ELISPOT and cytofluorometry techniques. To solve this issue, a diagnostic method was developed for assessing SARS-CoV-2-specific cellular immune response, which is based on a skin test followed by evaluating a delayed-type hypersensitivity reaction involving antigen-specific memory T-lymphocytes. A diagnostic preparation CoronaDerm-PS is based on Cord_PS, which is a hybrid recombinant protein consisting of parts of the SARS-CoV-2 structural proteins S, M, N, E. The specific activity of this chimeric antigen was analyzed in cultured T-lymphocyte activation test by assessing interferon-γ production using cytofluorometry. To investigate the chimeric antigen specific activity, a preclinical safety study with CoronaDerm-PS preparation in experimental animals was conducted. A dose-dependent developing skin reaction was observed in 90–100% of guinea pigs vaccinated by EpiVacCorona, CoviVac, Gam-COVID-Vac, which confirms a potential for assessing post-vaccination cellular immunity using CoronaDerm-PS preparation. Upon this, the presence of functionally active T-cell-antigenic epitopes in the recombinant polypeptide allows to evaluate SARS-CoV-2-specific response illustrated by detected response after Gam-COVID-Vac (S-protein) and EpiVacCorona (N-protein) vaccination. Thus, a skin test based on CoronaDerm-PS preparation may be a promising diagnostic tool for rapid mass screening requiring no specialized laboratory equipment for assessing populational SARS-CoV-2-specific immunity. Such a test is distinguished by advantages such as ease of analysis, high specificity and sensitivity. The final decision-making on using this test in a real-world practice may achieved after conducting further clinical safety and effectiveness trials.

Post-translational activation of the C-terminus of polypeptides for the synthesis of peptide thioesters and peptide thioester surrogates.

Semisynthesis using recombinant polypeptides is a powerful approach for the synthesis of proteins having a variety of modifications. Peptide thioesters, of which the peptide C-terminus is activated by a thioester, are utilized for coupling peptide building blocks. Biological methods employing intein have been a center for the C-terminal thioesterification of recombinant polypeptides. Chemical activation has emerged as an alternative methodology for synthesizing peptide thioesters from recombinant polypeptides. Chemical reactions are compatible with various solutions containing organic solvents, chaotropic reagents, or detergents that are generally incompatible with biomolecules such as intein. Despite the potential utility of chemical activation, available methods remain limited. This article introduces the methods for the chemical activation of a peptide C-terminus applied to the chemical synthesis of proteins. By showcasing these methodologies, we aim to accelerate the advancement of new chemical reactions and methodologies and broaden the frontiers for the chemical synthesis of proteins.

Development of an anti-tauopathy mucosal vaccine specifically targeting pathologic conformers

Alzheimer’s disease (AD) and related tauopathies are associated with pathological tau protein aggregation, which plays an important role in neurofibrillary degeneration and dementia. Targeted immunotherapy to eliminate pathological tau aggregates is known to improve cognitive deficits in AD animal models. The tau repeat domain (TauRD) plays a pivotal role in tau-microtubule interactions and is critically involved in the aggregation of hyperphosphorylated tau proteins. Because TauRD forms the structural core of tau aggregates, the development of immunotherapies that selectively target TauRD-induced pathological aggregates holds great promise for the modulation of tauopathies. In this study, we generated recombinant TauRD polypeptide that form neurofibrillary tangle-like structures and evaluated TauRD-specific immune responses following intranasal immunization in combination with the mucosal adjuvant FlaB. In BALB/C mice, repeated immunizations at one-week intervals induced robust TauRD-specific antibody responses in a TLR5-dependent manner. Notably, the resulting antiserum recognized only the aggregated form of TauRD, while ignoring monomeric TauRD. The antiserum effectively inhibited TauRD filament formation and promoted the phagocytic degradation of TauRD aggregate fragments by microglia. The antiserum also specifically recognized pathological tau conformers in the human AD brain. Based on these results, we engineered a built-in flagellin-adjuvanted TauRD (FlaB-TauRD) vaccine and tested its efficacy in a P301S transgenic mouse model. Mucosal immunization with FlaB-TauRD improved quality of life, as indicated by the amelioration of memory deficits, and alleviated tauopathy progression. Notably, the survival of the vaccinated mice was dramatically extended. In conclusion, we developed a mucosal vaccine that exclusively targets pathological tau conformers and prevents disease progression.

New Regenerative and Anti-Aging Medicine Approach Based on Single-Stranded Alpha-1 Collagen for Neo-Collagenesis Induction: Clinical and Instrumental Experience of a New Injective Polycomponent Formulation for Dermal Regeneration.

This study explores the efficacy of a novel polycomponent formulation (KARISMA Rh Collagen® FACE, Taumedika Srl, Rome, Italy), containing 200 mg/mL of non-crosslinked high-molecular-weight hyaluronic acid (HMW-HA), 200 μg/mL of a human recombinant polypeptide of collagen-1 alpha chain, and 40 mg/mL of carboxymethyl cellulose (CMC) as a regenerative medicine for skin regeneration and rejuvenation. This formulation combines non-crosslinked high-molecular-weight hyaluronic acid, human recombinant polypeptide of collagen-1 alpha chain, and carboxymethyl cellulose to stimulate collagen type I production and enhance skin hydration. This study involved 100 subjects with varying skin conditions, divided into three groups based on skin aging, smoking history, and facial scarring, to evaluate the product's effectiveness in skin regeneration and aesthetic improvement. The methodology included two injections of Karisma (2 mL for each injection) one month apart, with evaluations conducted using FACE-Q questionnaires, the SGAIS Questionnaire, and Antera 3D skin scanner measurements at baseline, 30 days, and 60 days post-treatment. The results demonstrated a significant reduction in skin roughness and an improvement in skin quality across all the groups, with no correlation between the outcomes and the patient's age. The subjective assessments also indicated high satisfaction with the treatment's aesthetic results. The analyzed data allow us to conclude that the single-stranded collagen with hyaluronic acid and carboxymethyl-cellulose formulation is able to stimulate the skin's regenerative response, yielding significant results both in vitro and, through our study, also in vivo. This new polycomponent formulation effectively stimulates skin regeneration, improving skin quality and texture, with significant aesthetic benefits perceived by patients, and a low incidence of adverse events, marking a promising advancement in regenerative medicine.

Dynamics of antibody response and bacterial shedding of Mycoplasma hyorhinis and M. hyosynoviae in oral fluids from experimentally inoculated pigs

Mycoplasma hyorhinis (Mhr) and M. hyosynoviae (Mhs) are commensal organisms of the upper respiratory tract and tonsils but may also cause arthritis in pigs. In this study, 8-week-old cesarean-derived colostrum-deprived (CDCD) pigs (n = 30; 3 groups, 10 pigs per group, 2 pigs per pen) were inoculated with Mhr, Mhs, or mock-inoculated with culture medium and then pen-based oral fluids were collected at different time points over the 56 days of the experimental study. Oral fluids tested by Mhr and Mhs quantitative real-time PCRs revealed Mhr DNA between day post inoculation (DPI) 5–52 and Mhs DNA between DPI 5–15. Oral fluids were likewise tested for antibody using isotype-specific (IgG, IgA, IgM) indirect ELISAs based on a recombinant chimeric polypeptide of variable lipoproteins (A-G) for Mhr and Tween 20-extracted surface proteins for Mhs. Mhr IgA was detected at DPI 7 and, relative to the control group, significant (p < 0.05) antibody responses were detected in the Mhr group between DPI 12–15 for IgM and DPI 36–56 for both IgA and IgG. In the Mhs group, IgM was detected at DPI 10 and significant (p < 0.05) IgG and IgA responses were detected at DPI 32–56 and DPI 44–56, respectively. This study demonstrated that oral fluid could serve as an effective and convenient antemortem sample for monitoring Mhr and Mhs in swine populations.

Physicochemical Characterization of a Biomimetic, Elastin-Inspired Polypeptide with Enhanced Thermoresponsive Properties and Improved Cell Adhesion.

Genetic engineering allows fine-tuning and controlling protein properties, thus exploiting the new derivatives to obtain novel materials and systems with improved capacity to actively interact with biological systems. The elastin-like polypeptides are tunable recombinant biopolymers that have proven to be ideal candidates for realizing bioactive interfaces that can interact with biological systems. They are characterized by a thermoresponsive behavior that is strictly related to their peculiar amino acid sequence. We describe here the rational design of a new biopolymer inspired by elastin and the comparison of its physicochemical properties with those of another already characterized member of the same protein class. To assess the cytocompatibility, the behavior of cells of different origins toward these components was evaluated. Our study shows that the biomimetic strategy adopted to design new elastin-based recombinant polypeptides represents a versatile and valuable tool for the development of protein-based materials with improved properties and advanced functionality.

Protective immunization against Enterohemorrhagic Escherichia coli and Shigella dysenteriae Type 1 by chitosan nanoparticle loaded with recombinant chimeric antigens comprising EIT and STX1B-IpaD

Increasing evidence demonstrated that Enterohemorrhagic Escherichia coli (EHEC) and Shigella dysenteriae type 1 (S. dysenteriae1) are considered pathogens, that are connected with diarrhea and are still the greatest cause of death in children under the age of five years, worldwide. EHEC and S. dysenteriae 1 infections can be prevented and managed using a vaccination strategy against pathogen attachment stages. In this study, the chitosan nanostructures were loaded with recombinant EIT and STX1B-IpaD polypeptides. The immunogenic properties of this nano-vaccine candidate were investigated. The EIT and STX1B-IpaD recombinant proteins were heterologous expressed, purified, and confirmed by western blotting. The chitosan nanoparticles, were used to encapsulate the purified proteins. The immunogenicity of recombinant nano vaccine candidate, was examined in three groups of BalB/c mice by injection, oral delivery, and combination of oral-injection. ELISA and antibody titer, evaluated the humoral immune response. Finally, all three mice groups were challenged by two pathogens to test the ability of the nano-vaccine candidate to protect against bacterial infection. The Sereny test in guinea pigs was used to confirm the neutralizing effect of immune sera in controlling S. dysenteriae 1, infections. SDS-PAGE and western blotting, confirmed the presence and specificity of 63 and 27 kDa recombinant EIT and STX1B-IpaD, respectively. The results show that the nanoparticles containing recombinant proteins could stimulate the systemic and mucosal immune systems by producing IgG and IgA, respectively. The challenge test showed that, the candidate nano-vaccine could protect the animal model from bacterial infection. The combination of multiple recombinant proteins, carrying several epitopes and natural nanoparticles could evocate remarkable humoral and mucosal responses and improve the protection properties of synthetic antigens. Furthermore, compared with other available antigen delivery methods, using oral delivery as immune priming and injection as a booster method, could act as combinatorial methods to achieve a higher level of immunity. This approach could present an appropriate vaccine candidate against both EHEC and S. dysenteriae 1.

Influence of dextran-70 on the cytotoxic effect of EMAP II on glioma cells in vitro

Aim. To evaluate with the use of the MTT test how the formation of a nanocomposite complex of the cytokine EMAP II with dextran-70 affects the cytotoxic effect of the free protein in glioma cell cultures of different origins: a standart culture U251MG cells and a primary culture of cells obtained from tumor fragments. Methods. The recombinant polypeptide EMAP II was obtained using gene engineering biotechnology. The study was conducted on the standard human glioma cell line U251MG and on primary cell cultures obtained from tumor fragments after surgical removal. Cell viability was determined using the MTT test. The cells were cultivated for a day with t the different concentrations from 1.0 pM to 10 μM of EMAP II and the EMAP II + dextran-70 complex im serum-free standard DMEM growth medium. Results. In our previous works, it has been shown that EMAP II exhibited dose-dependent cytotoxic properties in the concentration range of 1.0 pM – 10 μM on U251MG glioma cells and in primary cell cultures. The dose-effect curve in all cases has a complex pattern. Dextran-70 does not fundamentally affect the cytotoxic effect of EMAP II, but depending on the dose and type of cells, it shows the ability to slightly weaken/enhance the effect of the free protein. An increased sensitivity of the primary culture of glioma cells to the cytotoxic effect of the EMAP II + dextran-70 complex was revealed. Conclusions. Dextran-70 does not fundamentally affect the cytotoxic effect of EMAP II, but depending on the dose and type of cells, it shows the ability to slightly weaken/enhance the effect of the latter.

Evaluation of the Effectiveness of an Innovative Polycomponent Formulation on Adult and Aged Human Dermal Fibroblasts.

Skin aging is a dynamic process that determines structural alterations in ECM and reduction in dermal fibroblasts. The recent availability on the market of an innovative polycomponent formulation (KARISMA Rh Collagen® FACE, K) containing noncrosslinked high-molecular-weight hyaluronic acid (HMW-HA), a human recombinant polypeptide of collagen-1 alpha chain, and carboxymethyl cellulose (CMC), attracted our scientific interest in evaluating its biomolecular effects on human dermal adult and aged fibroblasts. After treatment with increasing K concentrations, cell proliferation, collagen I, prolyl 4-hydroxylase (P4HA1), an essential protein in collagen biosynthesis, and α-SMA levels were assessed. The fibroblast contractility, TGF-β1 levels, and oxidative stress markers were also evaluated. K formulation exposure led to a significant and dose-dependent increase in the proliferation and migration of adult fibroblasts. Of note, the K exposure counteracted the H2O2-induced aging by promoting cell proliferation, reducing β-galactosidase activity, and neutralizing the aging-associated oxidative damage. Moreover, an increase in collagen I, P4HA1, α-SMA, TGF-β1 levels, and improved contractility of adult and aged fibroblasts were observed after treatment. Overall, our results show evidence that the K treatment is efficacious in improving biological functions in adult fibroblasts and suppressing the biomolecular events associated with H2O2-induced cellular aging, thus supporting the regenerative and bio-revitalizing action of the K formulation helpful in preventing or treating skin aging.

РАЗРАБОТКА ОТЕЧЕСТВЕННОЙ ИММУНОФЕРМЕНТНОЙ ТЕСТ-СИСТЕМЫ ДЛЯ ДЕТЕКЦИИ ANTI-HEV IGМ В СЫВОРОТКЕ КРОВИ

Background. Though the Republic of Belarus does not belong to countries endemic for viral hepatitis E, numerous studies have proved that hepatitis E virus (HEV) actively circulates among humans and animals. However, the circulation is latent that makes it difficult to diagnose the infection in a timely manner. Objective. To develop and evaluate the quality of a domestic ELISA test system for the detection of anti-HEI IgM. Material and methods. 96-well plates, recombinant proteins ORF2 and ORF3 of the 3rd HEV genotype, conjugate of monoclonal antibodies to human IgM with horseradish peroxidase, solutions for dilution of serums and conjugate containing bovine serum albumin. Results. The recommended concentrations of recombinant polypeptides ORF2 and ORF3 of hepatitis E virus genotype 3 for sorption are 2 and 1 μg/ml, respectively. The optimum dilution of the conjugate is 1:13 000. False positive and false negative results were not detected, sensitivity and specificity being at least 99%. The mean value for coefficient of variation within one plate is 6.4%, within two plates is 11.3%. Conclusions. The characteristics of the developed national test system comply with the recommended standards, thus indicating the possibility of its implementation into clinical laboratory diagnostics.

Obtaining an expression vector containing the nucleotide sequence of the gene encoding Bet v 1 – the major allergen of birch pollen

An expression vector containing the gene encoding the most common isoform Bet v 1.0101 of the Bet v 1 protein, the major birch pollen allergen, was created for a subsequent expression in the prokaryotic system of Escherichia coli. Total RNA from birch pollen collected in Belarus was used as a matrix. The expression vector pJC40-Веt v 1 was obtained using molecular-genetic methods: cloning, ligation, transformation. The specificity of the cloned fragment was confirmed by sequencing. During the study, 14 rare Escherichia coli codons were identified in the coding part of the cloned gene. The triplets were evenly arranged in the nucleotide sequence; codon clustering was observed only in two cases. The total percentage of rare triplets (8.75 %) and the calculated value of the codon adaptation level (0.57) allow us to predict a sufficiently efficient expression of the studied gene. The data obtained will be used in the synthesis of the recombinant polypeptide Bet v 1.0101.

Targeting Novel LPXTG Surface Proteins with Monoclonal Antibodies for Immunomagnetic Separation of Listeria monocytogenes.

The Gram-positive bacterium Listeria monocytogenes causes a significantly high percentage of fatalities among human foodborne illnesses. Surface proteins, specifically expressed from a wide range of L. monocytogenes serotypes under selective enrichment culture conditions, can serve as targets for the isolation of this pathogen using antibody-based methods to facilitate molecular detection. In this study, monoclonal antibodies (MAbs), previously raised against the L. monocytogenes LPXTG surface proteins LMOf2365_0639 and LMOf2365_0148, were investigated for their ability to isolate L. monocytogenes from bacterial samples with immunomagnetic separation (IMS). Only 1 out of 35 MAbs against LMOf2365_0639, M3644, was capable of capturing L. monocytogenes. Among all the 24 MAbs examined against LMOf2365_0148, 4 MAbs, M3686, M3697, M3699, and M3700, were capable of capturing L. monocytogenes cells specifically from abbreviated primary selective enrichment cultures in either Palcam or LEB/UVM1 media or from mixed samples containing target and nontarget bacteria. MAb M3686 showed a unique specificity with the capability to capture strains of seven L. monocytogenes serotypes (1/2a, 1/2b, 1/2c, 3a, 4a, 4b, and 4d). These promising MAbs were subsequently characterized by quantitative measurements of antigen-binding affinity using surface plasmon resonance analysis and epitope mapping using overlapping recombinant polypeptides. The usefulness of these MAbs to LMOf2365_0148 in bacterial capture was consistent with their high affinities with KD constants in the nanomolar range and can be explored further for the development of an automated IMS method suitable for routine isolation of L. monocytogenes from food and environmental samples.

Actual view on skin scarring and clinical experience of conservative treatment of keloids

Scars are an urgent issue for many areas of practical medicine, especially for dermatovenerologists, cosmetologists and plastic surgeons. Every year, 100 million patients develop new scars and about 11 million of them are keloid. The issue of differential diagnosis of keloid and hypertrophic scars is still the subject of discussion among specialists. Despite the wide variety of available methods of treatment of keloid and hypertrophic – surgical excision, injections of glucocorticosteroids, laser therapy, cryotherapy, compression therapy and silicone bandages are the most effective and pathogenically rationalised methods for the correction of pathological scars. Promising methods of therapy are: injections of interferon, recombinant human TGF-β3 polypeptide, platelet-rich plasma, calcium channel blockers, lipofilling, the use of angiotensin-converting enzyme inhibitors, creams based on imiquimod and resiquimod, growth factors, stem cells. The article presents an up-to-date view on the processes of physiological and pathological scarring, the most important aspects of the differential diagnosis of keloid and hypertrophic scars, the understanding of which is important for choosing the right therapeutic strategy. Particular attention is paid to the pathophysiological mechanisms of action, the advantages and features of the use of silicone dressings. The authors present the clinical experience of successful two-stage correction of keloid scar – post-acne with the use of injection therapy with hyaluronidase and silicone dressings.

Recombinant supercharged polypeptides for safe and efficient heparin neutralization.

Heparin is a widely used anticoagulant agent in the clinic. After application, its anticoagulant effect must be reversed to prevent potential side effects. Protamine sulfate (PS) is the only clinically licensed antidote that has been used for this purpose in the last 80 years, which, however, provokes severe adverse effects, such as systemic hypotension and even death. Herein, we demonstrate the potential of supercharged polypeptides as a promising alternative for protamine sulfate. A series of supercharged polypeptides with multiple positive charges was recombinantly produced, and the heparin-neutralizing performance of the polypeptides was evaluated in comparison with PS. It was found that increasing the number of charges significantly enhanced the ability to neutralize heparin and resist the screening effect induced by salt. In particular, the polypeptide bearing 72 charges (K72) exhibited an excellent heparin-neutralizing behavior that was comparable to that of PS. Further in vivo studies revealed that the heparin-triggered bleeding was almost completely alleviated by K72 while a negligible toxic effect was observed. Therefore, such recombinant supercharged polypeptides might replace protamine sulfate as heparin-reversal agents.

604 The nuclear translocation of GPRC5A receptor is responsible for the regulation of keratinocyte adhesion and migration

We previously identified a strong overexpression of GPRC5A (G Protein-Coupled Receptor Class C Group 5 Member A) in keratinocytes from the skin wound edges in vivo, and in response to stiffness modulations in vitro, concomitantly to the translocation of its C-terminal region into the nucleolus. To better understand the role of this receptor in keratinocyte mechano-sensing, GPRC5A knock-down was performed in N/TERT-1 cells using a short-hairpin RNA approach, and a recombinant polypeptide mimicking the C-terminal region of GPRC5A (GPRC5A-Rec) was tested to rescue cell phenotype.

Expression and functional analysis of various structural domains of tobacco topoisomerase II: To understand the mechanistic insights of plant type II topoisomerases

In contrast to bacterial, yeast and animal systems, topoisomerases (topo) from plants have not been well studied. In this report, we generated four truncated topoisomerase II (Topo II) cDNA fragments encoding different functional domains of Nicotiana tabacum topo II (NtTopoII). Each of these recombinant polypeptides was expressed alone or in combination in temperature-sensitive topoisomerase II yeast mutants. Recombinant NtTopoII with truncated polypeptides fails to target the yeast nuclei and does not rescue the temperature-sensitive phenotype. In contrast complementation was achieved with the full-length NtTopoII, which localized to the yeast nucleus. These observations suggested the presence of a potent nuclear localization signal (NLS) in the extreme C-terminal 314 amino acid residues of NtTopoII that functioned effectively in the heterologous yeast system. Biochemical characterization of purified recombinant full-length and the partial NtTopoII polypeptides revealed that the ATP-binding and hydrolysis region of NtTopoIIwas located at 413 amino acid N-terminal region and this ATPase domain is functional both when it is expressed as a separate polypeptide or as part of the holoenzyme. The present findings also revealed that all NtTopoII truncated polypeptides were detrimental for in vitro supercoiled DNA relaxation and/or DNA nicking and ligation activity. Further, we discuss the possible disruption of coordinated macromolecular interface movements and the dimer interactions in truncated NtTopoII that are required for functional topoisomerase activity.