Electrochemical detection of bacterial endotoxin lipopolysaccharide (LPS) on gold electrode modified with DAL-PEG-DK5-PEG-OH - Antimicrobial peptide conjugate

This work describes fabrication of gold electrodes modified with peptide conjugate DAL-PEG-DK5-PEG-OH that enables ultra-sensitive detection of lipopolysaccharide (LPS) isolated from the reference strain of Escherichia coli O26:B6. The initial step of the established procedure implies immobilization of the fully protected DAL-PEG-DK5-PEG-OH peptide on the surface of the gold electrode previously modified by cysteamine. Then side chain- and Fmoc-deprotection was performed in situ on the electrode surface, followed by its incubation in 1 % of BSA solution to block non-specific bindings sites before LPS detection. The efficiency of the modification was confirmed by X-ray Photoelectron Spectroscopy (XPS) measurements. Additionally, the cyclic voltammetry (CV) and electrochemical impendance spectroscopy (EIS) were employed to monitor the effectiveness of each step of the modification. The obtained results confirmed that the presence of the surface-attached covalently bound peptide DAL-PEG-DK5-PEG-OH enables LPS detection by means of CV technique within the range from 5 × 10-13 to 5 × 10-4 g/mL in PBS solution. The established limit of detection (LOD) for EIS measurements was 4.93 × 10-21 g/mL with wide linear detection range from 5 × 10-21 to 5 × 10-14 g/mL in PBS solution. Furthermore, we confirmed the ability of the electrode to detect LPS in a complex biological samples, like mouse urine and human serum. The effectiveness of the electrodes in identifying LPS in both urine and serum matrices was confirmed for samples containing LPS at both 2.5 × 10-15 g/mL and 2.5 × 10-9 g/mL.

Screening and characterization of aptamers recognizing the periodontal pathogen Tannerella forsythia

Periodontal disease is one of the most common forms of inflammation. It is currently diagnosed by observing symptoms such as gingival bleeding and attachment loss. However, the detection of biomarkers that precede such symptoms would allow earlier diagnosis and prevention. Aptamers are short oligonucleotides or peptides that fold into three-dimensional conformations conferring the ability to bind molecular targets with high affinity and specificity. Here we report the selection of aptamers that bind specifically to the bacterium Tannerella forsythia, a pathogen frequently associated with periodontal disease. Two aptamers with the highest affinity were examined in more detail, revealing that their binding is probably dependent on mirolysin, a surface-associated protease secreted by the T. forsythia type-9 secretion system. The aptamers showed minimal cross-reactivity to other periodontopathogens and are therefore promising leads for the development of new tools to study the composition of the periodontitis-associated dysbiotic bacteriome as well as inexpensive new diagnostic assays.

Organotypic model of the gingiva for studying bacterial and viral pathogens implicated in periodontitis

Background

Three-dimensional (3D) tissue models bridge the gap between conventional two-dimensional cell cultures and animal models. The aim of this study was to develop an organotypic 3D gingival (OTG) model to provide a tool to investigate bacterial and viral pathogens in periodontitis.

Methods

The OTG model composed of gingival fibroblasts (GFs) and telomerase-immortalized gingival keratinocytes (TIGKs) was constructed and applied to study infections by Porphyromonas gingivalis and herpes simplex virus 1 (HSV-1). Immunohistochemical staining, confocal microscopy, qPCR, titration techniques, and colony-forming unit counts were applied to interrogate epithelial markers expression, monitor P. gingivalis and HSV-1 presence, and evaluate the immune response along with the efficiency of antimicrobial drugs.

Results

The OTG model resembled the morphology of the human gingiva. During infection, both pathogens penetrated deep into the tissue and persisted for a few days with P. gingivalis also forming a biofilm on the cell surface. The infection triggered the expression of inflammatory mediators in cells and both pathogens were efficiently eliminated by specific antimicrobials.

Conclusions

Presented OTG model constitutes a simple and convenient tool to study the interaction between bacterial and viral pathogens within the gingival tissue, including penetration, persistence and biofilm formation. It is also suitable to examine the efficiency of antimicrobial drugs.

Identification and characterization of aptameric inhibitors of human neutrophil elastase

Human neutrophil elastase (HNE) plays a pivotal role in innate immunity, inflammation, and tissue remodeling. Aberrant proteolytic activity of HNE contributes to organ destruction in various chronic inflammatory diseases including emphysema, asthma, and cystic fibrosis. Therefore, elastase inhibitors could alleviate the progression of these disorders. Here, we used the systematic evolution of ligands by exponential enrichment to develop ssDNA aptamers that specifically target HNE. We determined the specificity of the designed inhibitors and their inhibitory efficacy against HNE using biochemical and in vitro methods, including an assay of neutrophil activity. Our aptamers inhibit the elastinolytic activity of HNE with nanomolar potency and are highly specific for HNE and do not target other tested human proteases. As such, this study provides lead compounds suitable for the evaluation of their tissue-protective potential in animal models.

The influence of OSPE and PBL on competency-based pharmacy student self-assessment

BACKGROUND

In addition to vocational education and experience, the pharmaceutical profession's proper pursuit requires acquiring and continuously improving professional competencies. In recent years, the need has been increasingly highlighted for developing a medical education system based on helping students develop their competencies. It is necessary to adapt the tools and methods for assessing competencies during formal education. It will enable students to know the directions of further personal or professional development.

OBJECTIVE

The study aimed to compare pharmacy students' self-assessment outcomes before and after the Objective Structured Practical Examination (OSPE), which finished the Pharmaceutical Care course (PCc). The study's purpose was also to compare the outcomes of the self-assessment of competencies between the students of two academic years for whom classes on the PCc were provided by different methods.

METHODS

The study was conducted over two academic years (2018/2019 and 2019/2020) among 5th-year students enrolled at the Faculty of Pharmacy of the Jagiellonian University Medical College (JUMC) at the end of the Pharmaceutical Care course. Different teaching methods were used in the delivery of the course in these academic years. The students self-assessed their competencies using a questionnaire consisting of a list of personal and patient care competencies. The students completed the questionnaire before and after the OSPE, which followed the completion of the PCc.

RESULTS

Students' professional competencies as self-assessed after the exam were higher than those assessed before the exam. Differences were observed in both personal and patient care competencies. Students taking the course in the 2019/2020 academic year set their pre-OSPE competencies higher than students taking the PCc in 2018/2019.

CONCLUSION

The self-assessment scores increased for most competencies included in the study following the OSPE. This may suggest that taking part in the exam, involvement in patient's case simulations, and self-assessment of performance at individual stages of the exam contributed to increased subjective assessment of professional competencies.

Lipidation of Temporin-1CEb Derivatives as a Tool for Activity Improvement, Pros and Cons of the Approach

The alarming raise of multi-drug resistance among human microbial pathogens makes the development of novel therapeutics a priority task. In contrast to conventional antibiotics, antimicrobial peptides (AMPs), besides evoking a broad spectrum of activity against microorganisms, could offer additional benefits, such as the ability to neutralize toxins, modulate inflammatory response, eradicate bacterial and fungal biofilms or prevent their development. The latter properties are of special interest, as most antibiotics available on the market have limited ability to diffuse through rigid structures of biofilms. Lipidation of AMPs is considered as an effective approach for enhancement of their antimicrobial potential and in vivo stability; however, it could also have undesired impact on selectivity, solubility or the aggregation state of the modified peptides. In the present work, we describe the results of structural modifications of compounds designed based on cationic antimicrobial peptides DK5 and CAR-PEG-DK5, derivatized at their N-terminal part with fatty acids with different lengths of carbon chain. The proposed modifications substantially improved antimicrobial properties of the final compounds and their effectiveness in inhibition of biofilm development as well as eradication of pre-formed 24 h old biofilms of Candida albicans and Staphylococcus aureus. The most active compounds (C5-DK5, C12-DK5 and C12-CAR-PEG-DK5) were also potent against multi-drug resistant Staphylococcus aureus USA300 strain and clinical isolates of Pseudomonas aeruginosa. Both experimental and in silico methods revealed strong correlation between the length of fatty acid attached to the peptides and their final membranolytic properties, tendency to self-assemble and cytotoxicity.

The Potential Role of the Pharmacist in Supporting Patients with Depression - A Literature-Based Point of View

OBJECTIVE

The current article is aimed at identifying the best practice for counseling around depression in community and outpatient pharmacies, resulting in a draft guideline, proposing key steps and an algorithm for integration of community pharmacists into care for patients with depression.

METHODS

A literature review was performed followed by a detailed analysis, for the purpose of creation a short draft document used as a basis for creation of a guideline for pharmaceutical care for patients with depression. The technological scheme PRISMA flow diagram was applied. The paper is based on current knowledge, taking into consideration already published articles, guidelines, and recommendations about pharmaceutical care for patients with depression, giving a basis for further studies.

RESULTS

This paper includes two main sections: 1) depression - a short description of the main symptoms, risk factors and pharmacotherapy guidelines available in Bulgaria important for the purposes of ensuring qualitative community-based pharmaceutical care; and 2) the pharmacists' role in providing high-quality care - the main aspects of pharmaceutical care for patients with depression with specific examples.

CONCLUSION

The involvement of pharmacists in supporting depressive patients is crucial taking into account the specific characteristics of the pharmacological treatment: delayed onset of clinical results, risks in case of sudden pharmacotherapy abruption without physician consultation, multiple adverse drug reactions and drug-drug, drug-food and drug-alcohol interactions, etc. The current article could also be used as an initial document for creating a methodological guideline for providing pharmaceutical care services for patients with depression.

The Bactericidal Activity of Temporin Analogues Against Methicillin Resistant Staphylococcus aureus

Staphylococcus aureus is a major infectious agent responsible for a plethora of superficial skin infections and systemic diseases, including endocarditis and septic arthritis. Recent epidemiological data revealed the emergence of resistance to commonly used antibiotics, including increased numbers of both hospital- and community-acquired methicillin-resistant S. aureus (MRSA). Due to their potent antimicrobial functions, low potential to develop resistance, and immunogenicity, antimicrobial peptides (AMPs) are a promising alternative treatment for multidrug-resistant strains. Here, we examined the activity of a lysine-rich derivative of amphibian temporin-1CEb (DK5) conjugated to peptides that exert pro-proliferative and/or cytoprotective activity. Analysis of a library of synthetic peptides to identify those with antibacterial potential revealed that the most potent agent against multidrug-resistant S. aureus was a conjugate of a temporin analogue with the synthetic Leu-enkephalin analogue dalargin (DAL). DAL-PEG-DK5 exerted direct bactericidal effects via bacterial membrane disruption, leading to eradication of both planktonic and biofilm-associated staphylococci. Finally, we showed that accumulation of the peptide in the cytoplasm of human keratinocytes led to a marked clearance of intracellular MRSA, resulting in cytoprotection against invading bacteria. Collectively, the data showed that DAL-PEG-DK5 might be a potent antimicrobial agent for treatment of staphylococcal skin infections.

Conjugate of Enkephalin and Temporin Peptides as a Novel Therapeutic Agent for Sepsis

Antimicrobial peptides (AMPs) exhibit a wide spectrum of actions, ranging from a direct bactericidal effect to multifunctional activities as immune effector molecules. The aim of this study was to examine the anti-inflammatory properties of a DAL-PEG-DK5 conjugate composed of a lysine-rich derivative of amphibian temporin-1CEb (DK5) and dalargin (DAL), the synthetic Leu-enkephalin analogue. Detailed study of the endotoxin-neutralizing activity of the peptide revealed that DAL-PEG-DK5 interacts with LPS and the LPS binding protein (LBP). Moreover, DAL-PEG-DK5 prevented dimerization of TLR4 at the macrophage surface upon LPS stimulation. This inhibited activation of the NF-κB signaling pathway and markedly reduced pro-inflammatory cytokine production. Finally, we showed that aggregation of DAL-PEG-DK5 into amyloid-like structures induced by LPS neutralized the endotoxin proinflammatory activity. Consequently, DAL-PEG-DK5 reduced morbidity and mortality in vivo, in a mouse model of endotoxin-induced septic shock. Collectively, the data suggest that DAL-PEG-DK5 is a promising therapeutic compound for sepsis.

The nucleocapsid protein of human coronavirus NL63

Human coronavirus (HCoV) NL63 was first described in 2004 and is associated with respiratory tract disease of varying severity. At the genetic and structural level, HCoV-NL63 is similar to other members of the Coronavirinae subfamily, especially human coronavirus 229E (HCoV-229E). Detailed analysis, however, reveals several unique features of the pathogen. The coronaviral nucleocapsid protein is abundantly present in infected cells. It is a multi-domain, multi-functional protein important for viral replication and a number of cellular processes. The aim of the present study was to characterize the HCoV-NL63 nucleocapsid protein. Biochemical analyses revealed that the protein shares characteristics with homologous proteins encoded in other coronaviral genomes, with the N-terminal domain responsible for nucleic acid binding and the C-terminal domain involved in protein oligomerization. Surprisingly, analysis of the subcellular localization of the N protein of HCoV-NL63 revealed that, differently than homologous proteins from other coronaviral species except for SARS-CoV, it is not present in the nucleus of infected or transfected cells. Furthermore, no significant alteration in cell cycle progression in cells expressing the protein was observed. This is in stark contrast with results obtained for other coronaviruses, except for the SARS-CoV.

Porphyromonas gingivalis enzymes enhance infection with human metapneumovirus in vitro

Relatively recently discovered, human metapneumovirus (HMPV) is a human pathogen with worldwide prevalence, accounting for a substantial percentage of respiratory tract diseases. Concurrent viral and bacterial infections enable intricate mechanisms of cooperation between pathogens, which complicate the symptoms and outcome of the disease. Such bilateral interactions are based on the modulation of bacterial growth on epithelium pathologically altered during viral illness and the modulation of immune responses, as well as the enhancement of virus replication by bacterial virulence factors. This study showed that proteases produced by Porphyromonas gingivalis, a Gram-negative bacterium implicated in the development of periodontitis, named gingipains, facilitated HMPV replication in LLC-MK2 cells and may contribute to HMPV pathogenicity in patients with periodontitis. Gingipains at low nanomolar concentrations enabled HMPV replication and allowed virus propagation in vitro. In contrast to previously published data for influenza virus, however, Staphylococcus aureus proteases and human neutrophil elastase did not affect virus replication.

Infection with human coronavirus NL63 enhances streptococcal adherence to epithelial cells

Understanding the mechanisms of augmented bacterial pathogenicity in post-viral infections is the first step in the development of an effective therapy. This study assessed the effect of human coronavirus NL63 (HCoV-NL63) on the adherence of bacterial pathogens associated with respiratory tract illnesses. It was shown that HCoV-NL63 infection resulted in an increased adherence of Streptococcus pneumoniae to virus-infected cell lines and fully differentiated primary human airway epithelium cultures. The enhanced binding of bacteria correlated with an increased expression level of the platelet-activating factor receptor (PAF-R), but detailed evaluation of the bacterium-PAF-R interaction revealed a limited relevance of this process.

Myeloperoxidase-catalyzed oxidative inactivation of human kininogens: the impairment of kinin-precursor and prekallikrein-binding functions

Bradykinin-related vasoactive peptides (kinins) are important mediators of local and systemic inflammatory reactions. However, at local inflammatory foci, the production of kinins from proteinaceous precursors (kininogens) can be affected by reactive oxygen species released by phagocyte cells. One of the predominant oxidants at these places is hypochlorous acid which is formed from hydrogen peroxide and chloride ions by neutrophil myeloperoxidase. In this study, inactivation of human kininogens after oxidation with the myeloperoxidase-H2O2-chloride system was observed and analyzed by protein chemistry methods. The kinin release from oxidized kininogens by major kinin-producing enzymes, plasma and tissue kallikreins, proceed with a very low rate. This effect was assigned to apparent inability of kallikreins to process the kinin N-terminus owing to the conversion of the adjacent Met-361 residue to methionine sulfoxide. Additionally, the oxidized high-molecular mass kininogen lost its natural ability to bind plasma prekallikrein. This effect was assigned to the oxidation of Trp-569 residue within the prekallikrein-binding region which is subsequently destructed owing to cleavage of the peptide bond after that residue. One possible pathophysiological consequence of the described effects on kininogens could be the impairment of the normal assembly and triggering of the kinin-forming system on defense cell surfaces.

Degradation of human kininogens with the release of kinin peptides by extracellular proteinases of Candida spp

The secretion of proteolytic enzymes by pathogenic microorganisms is one of the most successful strategies used by pathogens to colonize and infect the host organism. The extracellular microbial proteinases can seriously deregulate the homeostatic proteolytic cascades of the host, including the kinin-forming system, repeatedly reported to be activated during bacterial infection. The current study assigns a kinin-releasing activity to secreted proteinases of Candida spp. yeasts, the major fungal pathogens of humans. Of several Candida species studied, C. parapsilosis and C. albicans in their invasive filamentous forms are shown to produce proteinases which most effectively degrade proteinaceous kinin precursors, the kininogens. These enzymes, classified as aspartyl proteinases, have the highest kininogen-degrading activity at low pH (approx. 3.5), but the associated production of bradykinin-related peptides from a small fraction of kininogen molecules is optimal at neutral pH (6.5). The peptides effectively interact with cellular B2-type kinin receptors. Moreover, kinin-related peptides capable of interacting with inflammation-induced B1-type receptors are also formed, but with a reversed pH dependence. The presented variability of the potential extracellular kinin production by secreted aspartyl proteinases of Candida spp. is consistent with the known adaptability of these opportunistic pathogens to different niches in the host organism.

Local perivascular application of low amounts of a plasmid encoding for vascular endothelial growth factor (VEGF165) is efficient for therapeutic angiogenesis in pigs

Clinical trials have demonstrated therapeutic benefit in inducing angiogenesis in chronic occlusive arterial disease. The route of application mostly used was the intramuscular injection of high dosages of plasmid. Therefore, a local perivascular application of low amounts of vascular endothelial growth factor (VEGF) plasmid was used in an interventional occlusion model, and the effect of VEGF on coronary and peripheral occlusions compared in the same animal model. Coronary and peripheral arteries were chronically occluded in Pietrain pigs using a non-surgical, interventional approach. Adventitial delivery of the DNA for VEGF was performed with a needle injection catheter. The DNA was applied as lipoplexes using the novel cationic liposomes DOCSPER. Optimized transfer conditions were used. Angiography, polymerase chain reaction (PCR), reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry were undertaken within a follow-up period of 6 months. Expression of the transfected VEGF gene was observed at 1 and 3 weeks following application. The DNA was detected up to 5 months following application. Around occluded coronary arteries, there was formation of new collaterals and arterial prolongation, whereas surrounding occluded peripheral arteries there was no collateralization but development of new arterial branches was seen. Results demonstrate that the response to VEGF is also sufficient, when minimal amounts of plasmid encoding for VEGF are applied locally into the perivasculature allowing for more safety of this therapy. Comparison of treatment of chronic coronary and peripheral arterial disease revealed differences in angiogenesis following VEGF application during a total follow-up period of almost 6 months which may be related to their different developmental origins. This may have important implications for developing future therapeutic strategies using VEGF in different vessels.