Controlling the aggregation of vital bacterial proteins could be one of the new research directions and form the basis for the search and development of antibacterial drugs with targeted action. Such ...approach may be considered as an alternative one to antibiotics. Amyloidogenic regions can, like antibacterial peptides, interact with the "parent" protein, for example, ribosomal S1 protein (specific only for bacteria), and interfere with its functioning. The aim of the work was to search for peptides based on the ribosomal S1 protein from
, exhibiting both aggregation and antibacterial properties. The biological system of the response of Gram-negative bacteria
to the action of peptides was characterized. Among the seven studied peptides, designed based on the S1 protein sequence, the R23I (modified by the addition of HIV transcription factor fragment for bacterial cell penetration), R23T (modified), and V10I (unmodified) peptides have biological activity that inhibits the growth of
cells, that is, they have antimicrobial activity. But, only the R23I peptide had the most pronounced activity comparable with the commercial antibiotics. We have compared the proteome of peptide-treated and intact
cells. These important data indicate a decrease in the level of energy metabolism and anabolic processes, including the processes of biosynthesis of proteins and nucleic acids. Under the action of 20 and 50 μg/mL R23I, a decrease in the number of proteins in
cells was observed and S1 ribosomal protein was absent. The obtained results are important for understanding the mechanism of amyloidogenic peptides with antimicrobial activity and can be used to develop new and improved analogues.
Melatonin (N-acetyl-5-methoxytryptamine, MEL), secreted by the pineal gland, plays an important role in regulation of various functions in the human body. There is evidence that MEL exhibits ...antitumor effect in various types of cancer. We studied the combined effect of MEL and drugs from different pharmacological groups, such as cytarabine (CYT) and navitoclax (ABT-737), on the state of the pool of acute myeloid leukemia (AML) tumor cell using the MV4-11 cell line as model. The combined action of MEL with CYT or ABT-737 contributed to the decrease in proliferative activity of leukemic cells, decrease in the membrane potential of mitochondria, and increase in the production of reactive oxygen species (ROS) and cytosolic Ca
2+
. We have shown that introduction of MEL together with CYT or ABT-737 increases expression of the C/EBP homologous protein (CHOP) and the autophagy marker LC3A/B and decreases expression of the protein disulfide isomerase (PDI) and binding immunoglobulin protein (BIP), and, therefore, could modulate endoplasmic reticulum (ER) stress and initiate autophagy. The findings support an early suggestion that MEL is able to provide benefits for cancer treatment and be considered as an adjunct to the drugs used in cancer therapy.
The need to develop new antimicrobial peptides is due to the high resistance of pathogenic bacteria to traditional antibiotics now and in the future. The creation of synthetic peptide constructs is a ...common and successful approach to the development of new antimicrobial peptides. In this work, we use a simple, flexible, and scalable technique to create hybrid antimicrobial peptides containing amyloidogenic regions of the ribosomal S1 protein from
. While the cell-penetrating peptide allows the peptide to enter the bacterial cell, the amyloidogenic site provides an antimicrobial effect by coaggregating with functional bacterial proteins. We have demonstrated the antimicrobial effects of the R23F, R23DI, and R23EI hybrid peptides against
, methicillin-resistant
(MRSA),
,
, and
. R23F, R23DI, and R23EI can be used as antimicrobial peptides against Gram-positive and Gram-negative bacteria resistant to traditional antibiotics.
Various amyloid aggregates, in particular, aggregates of amyloid β-proteins, demonstrate in vitro and in vivo cytotoxic effects associated with impairment of cell adhesion. We investigated the effect ...of amyloid aggregates of smooth-muscle titin on smooth-muscle-cell cultures. The aggregates were shown to impair cell adhesion, which was accompanied by disorganization of the actin cytoskeleton, formation of filopodia, lamellipodia, and stress fibers. Cells died after a 72-h contact with the amyloid aggregates. To understand the causes of impairment, we studied the effect of the microtopology of a titin-amyloid-aggregate-coated surface on fibroblast adhesion by atomic force microscopy. The calculated surface roughness values varied from 2.7 to 4.9 nm, which can be a cause of highly antiadhesive properties of this surface. As all amyloids have the similar structure and properties, it is quite likely that the antiadhesive effect is also intrinsic to amyloid aggregates of other proteins. These results are important for understanding the mechanisms of the negative effect of amyloids on cell adhesion.
Combining antimicrobial peptides (AMPs) with cell-penetrating peptides (CPPs) has shown promise in boosting antimicrobial potency, especially against Gram-negative bacteria. We examined the CPP-AMP ...interaction with distinct bacterial types based on cell wall differences. Our investigation focused on AMPs incorporating penetratin CPP and dihybrid peptides containing both cell-penetrating TAT protein fragments from the human immunodeficiency virus and Antennapedia peptide (Antp). Assessment of the peptides TAT-AMP, AMP-Antp, and TAT-AMP-Antp revealed their potential against Gram-positive strains (
, Methicillin-resistant
(MRSA), and
). Peptides TAT-AMP and AMP-Antp using an amyloidogenic AMP from S1 ribosomal protein
, at concentrations ranging from 3 to 12 μM, exhibited enhanced antimicrobial activity against
. TAT-AMP and TAT-AMP-Antp, using an amyloidogenic AMP from the S1 ribosomal protein
, at a concentration of 12 µM, demonstrated potent antimicrobial activity against
and MRSA. Notably, the TAT-AMP, at a concentration of 12 µM, effectively inhibited
(
) growth and displayed antimicrobial effects similar to gentamicin after 15 h of incubation. Peptide characteristics determined antimicrobial activity against diverse strains. The study highlights the intricate relationship between peptide properties and antimicrobial potential. Mechanisms of AMP action are closely tied to bacterial cell wall attributes. Peptides with the TAT fragment exhibited enhanced antimicrobial activity against
, MRSA, and
Peptides containing only the Antp fragment displayed lower activity. None of the investigated peptides demonstrated cytotoxic or cytostatic effects on either BT-474 cells or human skin fibroblasts. In conclusion, CPP-AMPs offer promise against various bacterial strains, offering insights for targeted antimicrobial development.
The escalating threat of multidrug-resistant pathogens necessitates innovative approaches to combat infectious diseases. In this study, we examined peptides R23FS*, V31KS*, and R44KS*, which were ...engineered to include an amyloidogenic fragment sourced from the S1 protein of S. aureus, along with one or two cell-penetrating peptide (CPP) components. We assessed the antimicrobial efficacy of these peptides in a liquid medium against various strains of both Gram-positive bacteria, including S. aureus (209P and 129B strains), MRSA (SA 180 and ATCC 43300 strains), and B. cereus (strain IP 5832), and Gram-negative bacteria such as P. aeruginosa (ATCC 28753 and 2943 strains) and E. coli (MG1655 and K12 strains). Peptides R23FS*, V31KS*, and R44KS* exhibited antimicrobial activity comparable to gentamicin and meropenem against all tested bacteria at concentrations ranging from 24 to 48 μM. The peptides showed a stronger antimicrobial effect against B. cereus. Notably, peptide R44KS* displayed high efficacy compared to peptides R23FS* and V31KS*, particularly evident at lower concentrations, resulting in significant inhibition of bacterial growth. Furthermore, modified peptides V31KS* and R44KS* demonstrated enhanced inhibitory effects on bacterial growth across different strains compared to their unmodified counterparts V31KS and R44KS. These results highlight the potential of integrating cell-penetrating peptides, amyloidogenic fragments, and amino acid residue modifications to advance the innovation in the field of antimicrobial peptides, thereby increasing their effectiveness against a broad spectrum of pathogens.
Octacalcium phosphate (OCP, Ca
H
(PO
)
·5H
O) is known to be a possible precursor of biological hydroxyapatite formation of organic bone tissue. OCP has higher biocompatibility and osseointegration ...rate compared to other calcium phosphates. In this work, the synthesis of low-temperature calcium phosphate compounds and substituted forms of those at physiological temperatures is shown. Strontium is used to improve bioactive properties of the material. Strontium was inserted into the OCP structure by ionic substitution in solutions. The processes of phase formation of low-temperature OCP with theoretical substitution of strontium for calcium up to 50 at.% in conditions close to physiological, i.e., temperature 35-37 °C and normal pressure, were described. The effect of strontium substitution range on changes in the crystal lattice of materials, the microstructural features, surface morphology and biological properties in vitro has been established. The results of the study indicate the effectiveness of using strontium in OCP for improving biocompatibility of OCP based composite materials intended for bone repair.
The development and testing of new antimicrobial peptides (AMPs) represent an important milestone toward the development of new antimicrobial drugs that can inhibit the growth of pathogens and ...multidrug-resistant microorganisms such as Pseudomonas aeruginosa, Gram-negative bacteria. Most AMPs achieve these goals through mechanisms that disrupt the normal permeability of the cell membrane, which ultimately leads to the death of the pathogenic cell. Here, we developed a unique combination of a membrane penetrating peptide and peptides prone to amyloidogenesis to create hybrid peptide: “cell penetrating peptide + linker + amyloidogenic peptide”. We evaluated the antimicrobial effects of two peptides that were developed from sequences with different propensities for amyloid formation. Among the two hybrid peptides, one was found with antibacterial activity comparable to antibiotic gentamicin sulfate. Our peptides showed no toxicity to eukaryotic cells. In addition, we evaluated the effect on the antimicrobial properties of amino acid substitutions in the non-amyloidogenic region of peptides. We compared the results with data on the predicted secondary structure, hydrophobicity, and antimicrobial properties of the original and modified peptides. In conclusion, our study demonstrates the promise of hybrid peptides based on amyloidogenic regions of the ribosomal S1 protein for the development of new antimicrobial drugs against P. aeruginosa.
This work investigated in vitro aggregation and amyloid properties of skeletal myosin binding protein-C (sMyBP-C) interacting in vivo with proteins of thick and thin filaments in the sarcomeric ...A-disc. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) found a rapid (5-10 min) formation of large (>2 μm) aggregates. sMyBP-C oligomers formed both at the initial 5-10 min and after 16 h of aggregation. Small angle X-ray scattering (SAXS) and DLS revealed sMyBP-C oligomers to consist of 7-10 monomers. TEM and atomic force microscopy (AFM) showed sMyBP-C to form amorphous aggregates (and, to a lesser degree, fibrillar structures) exhibiting no toxicity on cell culture. X-ray diffraction of sMyBP-C aggregates registered reflections attributed to a cross-β quaternary structure. Circular dichroism (CD) showed the formation of the amyloid-like structure to occur without changes in the sMyBP-C secondary structure. The obtained results indicating a high in vitro aggregability of sMyBP-C are, apparently, a consequence of structural features of the domain organization of proteins of this family. Formation of pathological amyloid or amyloid-like sMyBP-C aggregates in vivo is little probable due to amino-acid sequence low identity (<26%), alternating ordered/disordered regions in the protein molecule, and S-S bonds providing for general stability.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a promising agent for treatment of AML due to its specific apoptosis-inducing effect on tumor cells but not normal cells. ...However, emergence of resistance to TRAIL in the AML cells limits its potential as an antileukemic agent. Previously, we revealed increase in the resistance of the human AML THP-1 cells to the TRAIL-induced death during their LPS-dependent proinflammatory activation and in the
in vitro
model of LPS-independent proinflammatory activation – in a long-term high-density cell culture. In this study, we investigated mechanisms of this phenomenon using Western blot analysis, caspase 3 enzymatic activity analysis, quantitative reverse transcription-PCR, and flow cytometry. The results showed that the increased resistance to the TRAIL-induced cell death of AML THP-1 cells during their pro-inflammatory activation is associated with the decrease in the surface expression of the proapoptotic receptors TRAIL-R1/DR4 and TRAIL-R2/DR5, as well as with the increased content of members of the IAPs family – Livin and cIAP2. The results of this article open up new insights into the role of inflammation in formation of the resistance of AML cells to the action of mediators of antitumor immunity, in particular TRAIL.
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