Protein and Peptide Letters最新文献

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a significant and prevalent pathogen that poses a major challenge in healthcare environments. In light of the growing threat posed by multidrug-resistant organisms like MRSA, there is an urgent need for alternative therapeutic strategies. One promising avenue of research involves the use of antimicrobial peptides (AMPs). These naturally occurring molecules, which are part of the innate immune response in many organisms, have garnered attention for their ability to combat a wide range of pathogens.

Objectives: This study aimed to produce recombinant versions of Ib-AMP₄ and Oncorhyncin II and to evaluate their combined effects against MRSA (NCTC10442).

Methods: Escherichia coli BL21(DE₃) served as the expression host for the synthesized variants of the Ib-AMP₄ and Oncorhyncin II genes. The antimicrobial efficacy of these peptides against MRSA S. aureus (NCTC1042) was evaluated using a comprehensive methodology that encompassed the determination of the minimum inhibitory concentration (MIC), the performance of time-kill assays, and the analysis of growth kinetics.

Results: The individual antimicrobial activities of Ib-AMP₄ and Oncorhyncin II were assessed, revealing minimum inhibitory concentrations (MICs) of 27.75 μg/mL and 40.125 μg/mL against S. aureus (MRSA) (NCTC10442), respectively. The application of a checkerboard assay to evaluate the combination of these antimicrobial peptides (AMPs) demonstrated a synergistic interaction, which was further validated through time-kill and growth kinetic studies. When administered at double the MIC, a significant reduction in the log₁₀ CFU/mL of MRSA (NCTC 10442) was observed, underscoring the synergistic bacteriostatic effect mediated by the fractional inhibitory concentration (FIC) index of the two peptides.

Conclusion: Antimicrobial peptides (AMPs) have attracted significant interest owing to the growing intricacy of microbial infections. They constitute a promising category of novel antibiotics that warrant further investigation for the treatment of S. aureus infections and the enhancement of wound healing. Although certain AMPs can operate autonomously, others may necessitate a synergistic approach alongside conventional antibiotics. Studies examining the combined efficacy of Oncorhyncin II and Ib-AMP₄ against MRSA in vitro have revealed their effectiveness.

Introduction: This study aimed to investigate the anti-carcinogenic effects of recombinant L- methioninase (rBlmet) on the pancreatic cancer cell line MiaPaCa-2.

Methods: In this study, rBlmet was initially cloned, expressed, and purified. To increase enzyme activity, the His-tags on the enzyme were removed using thrombin. rBlmet was then applied to MiaPaCa- 2 cells, and the cell viability of MiaPaCa-2 cells was evaluated by neutral red assay after rBlmet treatment. The combined effect of etoposide with rBlmet against MiaPaCa-2 cells was also evaluated for 12 and 24 hours using a neutral red assay. Furthermore, cell morphology was evaluated by Giemsa and DAPI/F-actin staining methods. Survivin and caspase-3 gene expression levels were measured by RT-qPCR.

Results and discussion: The specific activity of the enzyme increased after His-tag elimination to 5.62 μmol/mg per minute. rBlmet showed a significant cytotoxic effect on the MiaPaCa-2 cell line. The IC₅₀ value (24 h) of rBlmet for MiaPaCa-2 cells was 3.02 U/mL. In addition, rBlmet increased the cytotoxic effect of etoposide on the MiaPaCa-2 cell line, while it showed less effect on HaCat, which is a normal human cell line. Furthermore, rBlmet increased caspase-3 expression and downregulated survivin gene expression in MiaPaCa-2 cell lines. It successfully inhibited the growth of Mia-PaCa-2 cells by exploiting exogenous methionine amino acid in the growth medium. This study revealed promising results. However, further studies are needed on additional pancreatic cancer cell lines and in vivo models.

Conclusion: Based on these findings, it can be concluded that rBlmet not only has great potential to treat pancreatic cancer in the future but can also be used as an adjuvant to enhance the effectiveness of chemotherapeutic agents like etoposide.

Like other vertebrates, amphibians possess innate and adaptive immune systems. At the center of the adaptive immune system is the Major Histocompatibility Complex. The important molecules of innate immunity are antimicrobial peptides (AMPs). These peptides are secreted by granular glands in the skin and protect the animal against microorganisms entering its body through the skin. AMPs offer an effective and rapid defense against pathogenic microorganisms and have cationic and amphiphilic structures. These peptides are small gene-encoded molecules of 8-50 amino acid residues synthesized by ribosomes. These small molecules typically exhibit activity against bacteria, viruses, fungi, and even cancer cells. It is known that today's amphibian AMPs originated from a common precursor gene 150 million years ago and that the origin of these peptides is preprodermaseptins. Today, antibiotic resistance has occurred due to the incorrect use of antibiotics. Traditional antibiotics are becoming increasingly inadequate. AMPs are considered promising candidates for the development of new-generation antibiotics. Therefore, new antibiotic discoveries are needed. AMPs are suitable molecules for new-generation antibiotics that are both fast and have different killing mechanisms. One of the biggest problems in the clinical applications of AMPs is their poor stability. AMPs generally have limited tropical applications because they are sensitive to protease degradation. Coating these peptides with nanomaterials to make them more stable can solve this problem.

Introduction: Abelmoschus esculentus (okra) from the Malvaceae family is widely used in culinary applications and is reported to have many potential therapeutic effects attributed to the compounds isolated from it. In this work, we set out to explore its seed proteome for the isolation of lectins and characterize them.

Methods: A protein of about 21kDa was isolated and purified using chromatography techniques from the ammonium sulphate crude protein extract. It was evaluated for hemagglutination activity on rabbit erythrocyte suspension, trypsin inhibitory activity using chemical assay, and evaluation of anti-cancer activity using cell lines. Mass and transcriptome analysis were done to deduce the complete sequence of the isolated protein.

Results: Using functional, mass, and transcriptome analysis, the protein was identified as AEL (Abelmoschus esculentus lectin), which was reported earlier. Only a partial sequence of AEL was known, and in this work, we have deduced its complete sequence. It showed significant anti-- cancer activity against HeLa (cervical cancer) and T84 (colon cancer) with MIC (Minimum inhibitory concentration) of 20μg/ml and 40% and 30% reduction in cell viability at 100μg/ml and insignificant effect on ACHN (adenocarcinoma) cell lines. No significant effect was seen with the tested doses on normal control human cell lines HEK293 (human embryonic kidney cells). The purified protein shows specificity for lactose and galactose in the hemagglutination assay and trypsin inhibition activity.

Discussion: Studies of okra seed proteome lead to purification of AEL, a 21 kDa protein with dual hemagglutination activity and trypsin inhibitory activity. It showed potential anticancer activity in cervical, colon cancer cell lines and minimal effects on adenocarcinoma and control cell lines, suggesting specificity. The complete sequence of AEL was elucidated which will aid in its bioinformatics analysis.

Conclusion: There are very few reported dual-acting lectins with potential anticancer activity, and this work will help understand their mechanistic interactions better.

Objective: This study aimed to identify novel proteins involved in retinoic acid (RA)-induced embryonic cleft palate development.

Methods: The palate tissues of the control and RA-treated E14.5 were dissected and subjected to iTRAQ-based proteomic analysis.

Results: Differential expression analysis identified 196 significantly upregulated and 149 downregulated considerably proteins in RA-induced palate tissues. Comprehensive Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed the significant involvement of cytoplasmic translation, ribosome biogenesis, glycolysis/gluconeogenesis, and glutathione metabolism pathways in cleft palate pathogenesis triggered by RA. In particular, ribosome-related pathways were highly enriched, while glycolysis was disrupted. Protein-protein interaction analysis, facilitated by the STRING database, revealed a tightly interconnected network of differentially expressed proteins. Further analysis using the cytoHubba plugin in Cytoscape identified ten hub proteins, including Eif4a1, Gapdh, Eno1, Imp3, Rps20, Rps27a, Eef2, Hsp90ab1, Rpl19, and Rps16, indicating their potential roles in RA-induced cleft palate development, and thus positioning them as potential biomarkers for cleft palate.

Conclusion: These findings provide valuable insights into the proteomic changes associated with RA-induced cleft palate and shed light on key pathways and proteins that can contribute significantly to the pathogenesis of this congenital condition.

Alzheimer's disease (AD) treatments currently available have ineffective results. Previously employed Acetylcholine esterase inhibitors and memantine, an NMDA receptor antagonist, target a single target structure that plays a complex role in the multifactorial progression of disease. Memantine moderates the toxic effects of excessive glutamate activity by blocking NMDA receptors, which decreases neurotoxicity in AD, while acetylcholine esterase inhibitors function by blocking cholinergic receptors (muscarinic and nicotinic), preventing the breakdown of acetylcholine, thereby enhancing cholinergic transmission, thus improving cognitive functions in mild to moderate stages of AD. Every drug class targets a distinct facet of the intricate pathophysiology of AD, indicating the diverse strategy required to counteract the advancement of this neurodegenerative disorder. Thus, patients are currently not getting much benefit from current drugs. A closer look at the course of AD revealed several potential target structures for future drug discovery. AD drug development strategies focus on developing new target structures in addition to well-established ones for combination treatment regimens, ideally with a single drug that can target two different target structures. Because of their roles in AD progression pathways like pathologic tau protein phosphorylations as well as amyloid β toxicity, protein kinases have been identified as potential targets. This review will give a quick rundown of the first inhibitors of single protein kinases, such as glycogen synthase kinase (gsk3) β, along with cyclin-dependent kinase 5. We will also look into novel inhibitors that target recently identified protein kinases in Alzheimer's disease, such as dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A). Additionally, multitargeting inhibitors, which target multiple protein kinases as well as those thought to be involved in other processes related to AD will be discussed. This kind of multitargeting offers prospective hope for improved patient outcomes down the road since it is the most effective way to impede multifactorial disease development.

Background: The role of Zona pellucida glycoprotein 3 (ZP3) is unclear in pancreatic adenocarcinoma (PAAD).

Objective: This study aimed to explore the role of ZP3 in PAAD.

Methods: A comparative analysis of ZP3 gene expression was performed to discern differences between various types of cancer and PAAD, leveraging data sourced from The Cancer Genome Atlas (TCGA). This study aimed to assess the role of ZP3 as a potential diagnostic marker for PAAD. The relationship between ZP3 levels and clinical characteristics, as well as patient outcomes, was scrutinized. Additionally, genomic enrichment analysis was carried out to uncover the underlying regulatory mechanisms associated with ZP3. The study further delved into the association of ZP3 with immune system interactions, checkpoint gene expression, Tumor Mutational Burden (TMB), microsatellite instability (MSI), and tumor stemness index (mRNAsi). The aberrant expression patterns of ZP3 in PAAD cell cultures were confirmed through the application of quantitative reverse transcription PCR (qRT-PCR) techniques.

Results: ZP3 exhibited aberrant expression in both pan-cancer and PAAD. A significant correlation was observed between increased levels of ZP3 expression in PAAD patients and histologic grade (p = 0.026). Elevated ZP3 expression in PAAD was found to be significantly associated with poorer overall survival (p = 0.003), progression-free survival (p = 0.012), and disease-specific survival (p = 0.002). In PAAD, the level of ZP3 gene expression was statistically significant (p < 0.001) and recognized as a key determinant of patient prognosis. ZP3 exhibited associations with various biological pathways, including primary immunodeficiency, oxidative phosphorylation, and other pathways. ZP3 expression demonstrated correlations with immune infiltration, immune checkpoint genes, TMB, MSI, and mRNAsi in PAAD. Moreover, a pronounced negative correlation was detected between ZP3 expression levels and the therapeutic effectiveness of various medications, including selumetinib, bleomycin, FH535, docetaxel, and tanespimycin, within the context of PAAD. Elevated levels of ZP3 were consistently observed in cell line models of PAAD.

Conclusion: ZP3 has the potential to serve as a prognostic biomarker and therapeutic target for patients with PAAD.

Autophagy is a self-eating cellular process in which the cell breaks down worn-out organelles, damaged/defective proteins, and toxins. Impaired autophagy is a significant factor in the development of various metabolic disorders, along with oxidative stress, inflammation, mitochondrial and endoplasmic reticulum dysfunction. These disorders pose a significant health and economic burden on the global human population, owing to their steadily rising prevalence. Therefore, modulating the expression of proteins involved in the autophagy-related pathways can be a promising avenue for curbing the development and progression of these disorders. Humanin (HN) is a 24-amino acid mitochondrial-derived peptide. It possesses anti-oxidant, anti-inflammatory, and pro-apoptotic properties. The analogs of HN can be generated by replacing specific amino acids in the polypeptide chain, thereby functionally modifying the peptide. Among these, humanin- glycine (HNG) is the most widely studied analog in both in vivo and in vitro disease models. It is far more potent than HN, with a potency that is 1000 times greater. To the best of our knowledge, this review is the first to discuss and examine the available evidence regarding the potential involvement of HN or its analogs in regulating autophagy pathways. The review primarily highlights that HN is an autophagy inducer, which can promote cell survival in the presence of metabolic and oxidative stress, particularly the HNG analog. Future research is imperative to comprehensively evaluate the effects of HN and its analogs on autophagy. Further investigations are needed to correlate its levels with various autophagic markers in different metabolic diseases, offering the potential for groundbreaking discoveries in understanding disease mechanisms and developing novel therapeutic strategies.

Background: The transformation of proteins from their native conformation into highly ordered fibrillar structures due to their misfolding and aggregation under particular conditions are described as beta-sheet enriched amyloid fibrils. The accumulation of these fibrils in different body parts is the major cause of several neurological and non-neurological conditions (proteinopathies).

Objectives: To prevent these proteinopathies, inhibition of protein aggregation is considered a promising strategy. Therefore, in this study, we synthesized montmorillonite (MMT) based poly- orthophenylenediamine (PoPD) nanocomposites (NCs) and characterized their size and morphology due to their remarkable biological properties. Further, the effect of these nanocomposites on inhibition of fibril formation was assessed.

Methods: These nanocomposites were evaluated for their anti-amyloidogenic potential on two model proteins of amyloidopathies, i.e., human lysozyme and human serum albumin (HL & HSA), by using several biophysical methods, such as Thioflavin T (ThT) and 1-anilino-8-naphthalene sulfonate (ANS) fluorescence, congo red dye binding assay (CR). Secondary structural content was evaluated by Circular dichroism (CD) spectroscopy.

Results: Results demonstrated that synthesized nanocomposites significantly inhibited fibril formation in dose-dependent manner that corresponds to their ability to arrest fibrillation. It is suggested that they may adsorb proteins to protect them against aggregation when they are subjected to aggregating conditions.

Conclusion: This study offers an opportunity to understand the mechanism of inhibition of fibril formation by nanocomposites, showing that they inhibit amyloid formation and amyloid diseases. Thus, the study concludes that these nanocomposites are promising candidates as therapeutic molecules for proteinopathies and are envisaged to enrich the area of personalized medicine, augmenting the human healthcare system.

Introduction: The progression of type 2 diabetes in humans appears to be linked to the loss of insulin-producing β-cells. One of the major contributors to β-cell loss is the formation of toxic human IAPP amyloid (hIAPP, Islet Amyloid Polypeptide, amylin) in the pancreas. Inhibiting the formation of toxic hIAPP amyloid could slow, if not prevent altogether, the progression of type 2 diabetes. Many non-human organisms also express amyloidogenic IAPP variants known to kill pancreatic cells and give rise to diabetes-like symptoms. Surprisingly, some of these non-human IAPP variants function as inhibitors of hIAPP aggregation, raising the possibility of developing non-human IAPP peptides into anti-diabetic therapeutic peptides. One such inhibitory IAPP variant is seal IAPP, which has been shown to inhibit hIAPP aggregation. Seal IAPP only differs from hIAPP by three amino acids. In this study, each of the six seal/human IAPP permutations was analyzed to identify the role of each of the three amino acid positions in inhibiting hIAPP aggregation.

Aims: This study aimed to identify the minimal amino acid substitutions to yield a peptide inhibitor of human IAPP aggregation.

Objective: The goal of the study was to determine the minimal amino acid substitutions necessary to convert human IAPP into an amyloid-inhibiting peptide.

Methods: The formation of toxic hIAPP amyloid was monitored using Thioflavin T binding assays, atomic force microscopy, and MTT cell rescue studies.

Results: One seal IAPP variant retained amyloid-inhibition activity, and two variants appeared to be more amyloidogenic and toxic than wild-type human IAPP.

Conclusion: These results suggest that inhibition of hIAPP requires both the H18R and F23L substitutions of hIAPP.