International Journal of Peptide Research and Therapeutics最新文献

Mitogen-inducible gene 6 (Mig6) is a tumor suppressor that inactivates oncogenic kinases by disrupting the dimerization of kinase domain using its segment 1 (SGT1). Traditionally, Mig6 has been documented as a cognate binder of the ErbB family of receptor tyrosine kinases (RTKs). Considering that the kinase domains of RTKs are highly conserved that share significant homology in sequence, structure and function, we herein assumed that the Mig6 SGT1 should not only bind to ErbBs, but can also target and then inhibit other RTKs in bone cancers and bone cancer pain. In this study, we systematically profiled the binding behavior of Mig6 SGT1 segment peptide against various ontology-enriched RTKs that are semantically relevant with bone cancers. A variety of RTKs were computationally identified as the potential binding hits of Mig6 SGT1; most of them have been previously reported to be involved in the cell signaling pathways of bone cancer pathogenesis. Binding analysis further revealed that the VEGFR1 and VEGFR2 kinases are two potent binders of Mig6 SGT1, which are comparable with or even stronger than the EGFR, while other two FGFR1 and FGFR2 kinases were also observed to have a moderate potency to Mig6 SGT1. Interaction modeling and dynamics simulation revealed that the full-length Mig6 SGT1 segment contains three hotspot sub-peptide fragments sbpt1, sbpt2 and sbpt3, which are primarily responsible for SGT1 binding to RTKs and can interact with the kinase dimerization interface in an independent manner. The sbpt2 was found as a moderately potent binder of VEGFR1 kinase domain at molecular level, while the Mig6 SGT1 and its derived sbpt1 and sbpt2 were observed to have similar suppressing effects on human osteosarcoma at cellular level.

Improper use of antibiotics has alarmingly led to the emergence of antibiotic resistance. Hence, this necessitated an urgent need to find a suitable alternative to traditional antibiotics. Endolysins are enzymes produced at the end of the phage replication cycle and destroy the peptidoglycan of the bacterial cell wall leading to the lysis of the host bacterial cell. These enzymes are species-specific, exhibit high lytic activity, and it is almost impossible for bacteria to develop resistance against them. Lysozyme subfamily 2 (LYZ2) is a modular region of the gene 61 (gp61) of phage φMR11 with lytic activity against S. aureus. However, it does not possess a cell wall recognition domain, which is usually found in lysins acting against gram-positive bacteria. Therefore, in this study, we engineered the LYZ2 by fusing a Staphylococcus aureus cell wall-binding domain (CBD) to its C-terminus and cloned the chimeric protein (named chimeric Staphylococcus aureus–targeting enzybiotic (CST_Enz)) into the pET28a vector, and expressed the enzyme in E. coli BL21 (DE3) cell. The engineered lysin displayed a rapid and specific lytic activity against susceptible and Methicillin-resistant Staphylococcus aureus and inhibited the growth of the bacteria at concentrations higher than 0.5 µg/ml. Besides, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of CST_Enz were both approximately 64 times lower than those of LYZ2, indicating the increased bacteriolytic activity of the engineered version of the enzyme. In conclusion, the chimeric enzybiotic can be used as a potential antibacterial agent to limit infections caused by methicillin-resistant Staphylococcus aureus (MRSA).

Background: GHRH is produced in the hypothalamus and affects various tissues beyond the pituitary, including the lungs. GHRH antagonists exert anti-inflammatory properties in several experimental models of disease, but their role inprotecting the endothelial barrier during inflammation is less understood. This study investigates the effects ofGHRHAnt on LPS-induced endothelial dysfunction.

Methods: BPAEC and HMVEC-L cells were exposed to LPS to induce endothelial injury. GHRHAnt was administered eitherpre- or post-LPS treatment. Western blot analysis was used to evaluate protein expression levels. Paracellularpermeability was assessed utilizing FITC-dextran assay to evaluate endothelial barrier function.

Results: GHRHAnt post-treatment significantly reduced LPS-induced MLC2 phosphorylation and cofilin activation inBPAECs. Furthermore, pretreatment with GHRHAnt enhanced barrier function and ameliorated LPS-inducedhyperpermeability in both human and bovine endothelial cells.

Conclusions: GHRHAnt treatment mitigates LPS-induced endothelial barrier dysfunction. These findings suggest that GHRHAntcould serve as potential therapeutic agents towards endothelial dysfunction-related illness (e.g. sepsis).

Peptides as drugs are a promising therapeutic method. Peptides modulate diverse biological processes and are synthesized with high purity. Due to their low cell permeability, peptide drugs target extracellular receptors. The peptibody comprises the biologically active Fc region and the peptide itself. Various peptides with specific biological activities have been successfully fused into the Fc region. These peptide-Fc fusions, also known as peptibodies, offer an excellent therapeutic alternative to monoclonal antibodies. They comprise biologically active peptides bound to the Fc region. This approach retains antibodies' beneficial characteristics, especially the enhanced affinity resulting from Fc dimerization and extended plasma residence time. Peptibodies can be produced in Escherichia coli using recombinant methods. In this study, we describe peptibodies and analyze different types of peptibodies collected for research.

The title peptide, oxytocin trisulfide (3), was required on a multi-100 mg scale, as part of an analytical method validation process for the clinically and commercially important product “Oxytocin Injection,” which is a sterile isotonic injectable formulation of oxytocin (2). We report here that previous chemistry from our academic laboratory can be successfully scaled up in the biotechnology sector to indeed provide pure 3 (overall yield 6–7%, > 95% purity). The scaled-up synthesis also gave rise, somewhat unexpectedly, to modest levels of oxytocin tetrasulfide (4), and even higher homologues. Protocols for synthesis, purification, and characterization [by HPLC, mass spectrometry and amino acid analysis] are described and discussed, along with possible mechanistic explanations for our findings.

Fish and other members of aquatic habitats are in constant contact with the microbes that trigger their immune system to produce immune components along with mucus. Compounds like lysozymes, proteases, lectins and peroxidase were reported in many studies. The study aims to identify and characterize the immune components present in the epidermal mucus of Channa punctatus. For this, antibacterial and antifungal efficacy was tested first using agar well diffusion assay and MIC was measured. Maximum activity against bacteria’s E. coli, S. aureus and Fungus H. gramineum was observed. FESEM analysis was performed to reveal the mechanism of the antimicrobial activity. Physico–chemical stability of mucus was also checked by exposing to various parameters such as (temperature, pH, proteases and surfactants). Precipitated proteins of mucus were separated using 12% SDS-PAGE assay. The band was digested using trypsin digestion and digested peptides were subjected to LCMSMS analysis for identification and on characterization using MASCOT servers 2 proteins (Hemoglobin subunit beta-A-globin chain and Galactose specific lectins nattectin) with number of fragmented unique peptides were obtained. Insilico predictions of antibacterial, antifungal, antiviral and anticancerous properties of peptides were also determined to support the role of mucus in microbial defense and therapeutical applications using the servers AMPfun, DBAASP and APD3.

In this work, we designed new terpenoid-peptide conjugates to target the epidermal growth factor receptor (EGFR) and its double mutant EGFR T790M/L858R which are implicated in many cancers. The peptides utilized were MEGPSKCCFSLALSH (MFSL), a new peptide sequence designed by mutating an ErbB2 targeting peptide, while the sequence VPWXE was derived from a peptide motif known to target tumor cells. Each of the peptides were conjugated to four terpenoids, 23-hydroxy betulinic acid (HB), oleanolic acid, perillic acid, and ursolic acid. Molecular docking and molecular dynamics (MD) simulations with the kinase domain of both the wild type and double mutant EGFR receptors revealed that the conjugates formed H-bonds and hydrophobic interactions with key residues in the hinge region, A-loop, and DFG motif, while in the case of the double mutant, interactions also occurred with C-terminal residues and with allosteric sites. MMGBSA analysis revealed higher binding energies for the double mutant. Six of the conjugates were synthesized and self-assembled into nanoassemblies and their impact on tumor cells expressing the wild type and double mutant receptor revealed that higher apoptosis was induced by MFSL conjugates, particularly in cells expressing the double mutant EGFR receptor. The HB and ursolate conjugates were found to be more potent against the tumor cell lines. Overall, these results indicate that these peptides and peptide conjugates can effectively bind to both the wild type and the T790M/L858R receptors to target tumor cells. Such peptide conjugates may be further potentially developed as therapeutic agents for further laboratory studies against tumors overexpressing EGFR.

Ras Proteins, play a pivotal role in the proliferation pathways, and Ras mutant forms are well-established cancer drivers. Ras mutations are found in about 30% of all human cancers widely known as challenging diseases to control and treat. The direct inhibition of Ras is challenging and makes Ras an “undruggable” target for many years. The important reason is, that Ras protein has a unique smooth surface and shows different dynamicity upon binding GDP and GTP. As a result, interfering peptides (IPs) targeting the Ras family protein-protein interactions (PPIs) are considered more likely to bind Ras effectively and inhibit the downstream signaling. In this review, we aimed to cover the recent approaches to design the peptides that target Ras family proteins, focusing on in silico methods. In this regard, the anti-cancer peptide development approaches including design and delivery strategies are discussed. Later, more specific methods regarding Ras-specific peptide design are presented. In conclusion, IPs are a promising group of cancer therapeutics to combat Ras mutant cancers. For future perspectives to have these peptides in clinical use, co-inhibition of other cancer targets as well as improving the pharmacokinetic features of peptides are suggested.

In this study, we describe the isolation of a new isoform, l-Amino acid oxidase (LAAO), referred to as Balt-LAAO-II, from Bothrops alternatus snake venom, which was highly purified using a combination of molecular exclusion (Sephadex G-75) and RP-HPLC chromatographic steps. SDS-PAGE analysis showed that purified Balt-LAAO-II had a molecular weight of (sim )66 kDa. The N-terminal amino acid sequence and internal peptide sequences showed close structural homology to those of other snake venom l-Amino acid oxidases. This enzyme induces in vitro cytotoxicity in cultured human leukemic HL60 cells. Cells were grown in RPMI medium and incubated with the isoform Balt-LAAO-II (1, 10, and 100 (mu )g/mL) for up to 72 h. All three concentrations of venom markedly decreased cell viability from 6 h onwards based on staining with propidium iodide, the reduction of 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and the uptake of neutral red. Flow cytometry showed that all isoforms of Balt-LAAO-II and whole venom concentrations induced apoptosis after 2–6 h of incubation. Morphological analysis of cells incubated with the isoform Balt-LAAO-II and whole venom showed cell rounding and lysis, which increased with venom concentration and duration of incubation. These results show that the isoform Balt-LAAO-II from venom Bothrops alternatus is cytotoxic to cultured HL60 cells, suggesting that this damage may involve the apoptotic and oxidative stress pathways.