Protein and Peptide Letters最新文献

Background: Early diagnosis remains difficult because the early symptoms of thymoma are atypical.

Objectives: This study aimed to analyze the changes of serum proteins in the early stage of thymoma (stage I/II) by proteomics method and to screen and validate candidate biomarkers.

Methods: Proteins were extracted from 8 sera patients with stage I/II thymoma and 9 healthy controls. The levels of serum proteins were detected by data-independent acquisition (DIA) quantitative proteomics techniques, and the differential proteins were identified. The proteomic results were verified by enzyme-linked immunosorbent assay. Additionally, differentially expressed proteins were analyzed using receiver operating characteristic curves (ROC).

Results: There were 80 differentially expressed proteins between the patients with thymoma and the healthy control group, among which 39 were up-regulated and 41 were down-regulated. Differential protein enrichment is involved in environmental information processing, signaling molecules and interactions, and in the body system and the immune system. The analysis of receptor working characteristic curves showed that the areas under the curve of CORO1A, SAA1 and LTA4H were all larger than 0.8, indicating that these proteins had good diagnostic value.

Conclusion: CORO1A, SAA1 and LTA4H may be new biomarkers for early screening of thymoma.

Phage therapy, a promising alternative to combat multidrug-resistant bacterial infections, harnesses the lytic cycle of bacteriophages to target and eliminate bacteria. Key players in this process are the phage lysis proteins, including holin, endolysin, and spanin, which work synergistically to disrupt the bacterial cell wall and induce lysis. Understanding the structure and function of these proteins is crucial for the development of effective therapies. Recombinant versions of these proteins have been engineered to enhance their stability and efficacy. Recent progress in the field has led to the approval of bacteriophage-based therapeutics as drugs, paving the way for their clinical use. These proteins can be combined in phage cocktails or combined with antibiotics to enhance their activity against bacterial biofilms, a common cause of treatment failure. Animal studies and clinical trials are being conducted to evaluate the safety and efficacy of phage therapy in humans. Overall, phage therapy holds great potential as a valuable tool in the fight against multidrug- resistant bacteria, offering hope for the future of infectious disease treatment.

Background: Resistance to anti-tumor agents targeting the epidermal growth factor receptor (EGFR) reduces treatment response and requires the development of novel EGFR antagonists. Mutant epidermal growth factor (EGF) forms with reduced agonistic activity could be promising agents in cancer treatment.

Methods: EGF D46G affinity to EGFR domain III was assessed with affinity chromatography. EGF D46G acute toxicity in Af albino mice at 320 and 3200 μg/kg subcutaneous doses was evaluated. EGF D46G activity in human epidermoid carcinoma cells at 10 ng/mL concentration in serum-free medium and in subcutaneous Ehrlich ascites carcinoma mice model at 320 μg/kg dose was studied.

Results: The D46G substitution decreases the thermal stability of EGF complexes with EGFR domain III by decreasing the ability of the C-terminus to be released from the intermolecular β- sheet. However, with remaining binding sites for EGFR domain I, EGF D46G effectively competes with other EGF-like growth factors for binding to EGFR and does not demonstrate toxic effects in mice. EGF D46G inhibits the proliferation of human epidermoid carcinoma cells compared to native EGF. A single subcutaneous administration of EGF D46G along with Ehrlich carcinoma cells injection inhibits the proliferation of these cells and delays tumor formation for up to seven days.

Conclusion: EGF D46G can be defined as a partial EGFR agonist as this mutant form demonstrates reduced agonistic activity compared to native EGF. The study emphasizes the role of the EGF C-terminus in establishing interactions with EGFR domain III, which are necessary for EGFR activation and subsequent proliferation of cells.

Background: Protein A resins have been widely used for product capture during mAb, bispecific antibody (bsAb), and Fc-fusion protein purification. While Protein A ligands mainly bind the Fc region, many of them can also bind the VH3 domain. During mAb/bsAb purification, certain truncated byproducts may contain the same Fc region as the product but fewer numbers of the VH3 domain. In such a scenario, VH3-binding Protein A resins provide a potential means for byproduct separation based on the difference in VH3-binding valency. As the ligands of different VH3-binding Protein A resins are derived from distinct domains of the native Protein A, it would be interesting to know whether they possess comparable capabilities for separating species with the same Fc region but different numbers of VH3 domain.

Objective: This study aims to explore the potential of different VH3-binding Protein A resins for separating antibody species with the same Fc region but different numbers of VH3 domain.

Methods: The VH3 Fab was released from a VH3-containing mAb by papain digestion. Post digestion, the released VH3 Fab was purified sequentially using CaptureSelect CH1-XL and MabSelect SuRe affinity chromatography. The purified VH3 Fab was used as the load material to assess the dynamic binding capacity (DBC) of five VH3-binding Protein A resins (i.e., Amshpere A3, Jetted A50, MabCaptureC, MabSelect and MabSelect PrismA). The potential of VH3-binding Protein A resins for separating species having the same Fc region but different numbers of VH3 domain was evaluated using an artificial mixture composed of the product and a truncated byproduct, which contained one and zero VH3 domain, respectively (both species contained the same Fc region). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to monitor Fab purification and separation of species containing the same Fc region but different numbers of VH3 domain.

Results: When loaded with an isolated VH3 Fab, different VH3-binding Protein A resins showed varied DBCs. Nevertheless, when these Protein A resins were used to separate a truncated byproduct, which contained the Fc region only without any VH3 domain, from the product, which included one VH3 domain in addition to the Fc region, they showed comparable capabilities for separating these two species.

Conclusion: Although different VH3-binding Protein A resins showed varied DBCs towards a VH3 Fab, they exhibited comparable capabilities for separating species with the same Fc region but different numbers of VH3 domain.

Background: Colorectal cancer remains to be the third leading cause of cancer mortality rates. Despite the diverse effects of the miRNA cluster located in PVT1 of 8q24.21 across various tumors, the specific biological function in colorectal cancer has not been clarified.

Methods: The amplification of the miR-1204 cluster was analyzed with the cBioPortal database, while the expression and survival analysis of the miRNAs in the cluster were obtained from several GEO databases of colorectal cancer. To investigate the functional role of miR-1204 in colorectal cancer, overexpression and silencing experiments were performed by miR-1204 mimic and inhibitor transfection in colorectal cancer cell lines, respectively. Then, the effects of miR-1204 on cell proliferation were assessed through CCK-8, colony formation, and Edu assay. In addition, cell migration was evaluated using wound healing and Transwell assay. Moreover, candidate genes identified through RNA sequencing and predicted databases were identified and validated using PCR and western blot. A Dual-luciferase reporter experiment was conducted to identify MASPIN as the target gene of miR-1204.

Results: In colorectal cancer, the miR-1204 cluster exhibited high amplification, and the expression levels of several cluster miRNAs were also significantly increased. Furthermore, miR-1204 was found to be significantly associated with disease-specific survival according to the analysis of GSE17536. Functional experiments demonstrated that transfection of miR-1204 mimic or inhibitor could enhance or decrease cancer cell proliferation and migration. MASPIN was identified as a target of miR-1204. Additionally, the overexpression of MASPIN partially rescued the effect of miR-1204 mimics on tumorigenic abilities in LOVO cells.

Conclusion: miR-1204 positioning in 8q24.21 promotes the proliferation and migration of colorectal cancer cells by targeting MASPIN.

Protein arginine methylation stands as a prevalent post-translational modification process, exerting vital roles in cellular signal transduction, gene expression, and cell cycle regulation. Amidst the protein arginine methyltransferase (PRMT) family, PRMT2 stands as a less explored constituent. Nonetheless, its regulatory roles in transcriptional regulation, post-transcriptional modification, methylation activity regulation, immunoregulation, and developmental regulation have garnered attention. These capabilities enable PRMT2 to exert pivotal regulatory functions in certain malignancies, metabolic disorders, inflammatory diseases, and atherosclerosis. In this review, we highlight the structure and functions of PRMT2, emphasizing its association with diseases. We also discuss PRMT2 inhibitors and explore the potential for therapeutic targeting.

Background: Binding appropriate cellular receptors is a crucial step of a lifecycle for any virus. Structure of receptor-binding domain for a viral surface protein has to be determined before the start of future drug design projects.

Objectives: Investigation of pH-induced changes in the secondary structure for a capsid peptide with loss of function mutation can shed some light on the mechanism of entrance.

Methods: Spectroscopic methods were accompanied by electrophoresis, ultrafiltration, and computational biochemistry.

Results: In this study, we showed that a peptide from the receptor-binding domain of Parvovirus B19 VP1 capsid (residues 13-31) is beta-structural at pH=7.4 in 0.01 M phosphate buffer, but alpha- helical at pH=5.0, according to the circular dichroism (CD) spectroscopy results. Results of infra- red (IR) spectroscopy showed that the same peptide exists in both alpha-helical and beta-structural conformations in partial dehydration conditions both at pH=7.4 and pH=5.0. In contrast, the peptide with Y20W mutation, which is known to block the internalization of the virus, forms mostly alpha-helical conformation in partial dehydration conditions at pH=7.4. According to our hypothesis, an intermolecular antiparallel beta structure formed by the wild-type peptide in its tetramers at pH=7.4 is the prototype of the similar intermolecular antiparallel beta structure formed by the corresponding part of Parvovirus B19 receptor-binding domain with its cellular receptor (AXL).

Conclusion: Loss of function Y20W substitution in VP1 capsid protein prevents the shift into the beta-structural state by the way of alpha helix stabilization and the decrease of its ability to turn into the disordered state.

Neurotensin (NTS) and its receptors (NTSRs) have long been the subject of study and have shown to have a vital function in a variety of systems. They are specifically implicated in the development of tumors and have both oncogenic and anti-apoptotic effects. Neurotensin receptor 2 (NTSR2), like NTSR1, belongs to the G protein-coupled receptor family and has been linked to analgesia, mental disorders, and hematological cancers. However, several research reports have revealed that it exists in numerous different systems. As a result, it seems to be an extremely promising therapeutic target for a variety of diseases. As NTSR2 is particularly prevalent in the brain and has different distribution and developmental characteristics from NTSR1, it may play a specific role in the nervous system. The present review summarizes the expression and function of NTSR2 in different systems, to highlight its potential as a diagnostic tool or therapeutic target.

Background: The rat intestinal fatty acid-binding protein (I-FABP) is expressed in the small intestine and is involved in the absorption and transport of dietary fatty acids. It is used as a marker for intestinal injury and is associated with various gastrointestinal disorders. I-FABP has been studied extensively using conventional experimental and computational techniques. However, the detection of intrinsically disordered regions requires the application of special sampling molecular dynamics simulations along with certain bioinformatics because conventional computational and experimental studies face challenges in identifying the features of intrinsic disorder.

Methods: Replica exchange molecular dynamics simulations were conducted along with bioinformatics studies to gain deeper insights into the structural properties of I-FABP. Specifically, the Cα and Hα chemical shift values werecalculated, and the findings were compared to the experiments. Furthermore, secondary and tertiary structure properties were also calculated, and the protein was clustered using k-means clustering. The end-to-end distance and radius of gyration values were reported for the protein in an aqueous solution medium. In addition, its disorder tendency was studied using various bioinformatics tools.

Results and conclusion: It was reported that I-FABP is a flexible protein with regions that demonstrate intrinsic disorder characteristics. This flexibility and intrinsic disorder characteristics of IFABP may be related to its nature in ligand binding processes.

Metabolic dysfunction-associated Fatty Liver Disease (MAFLD) is a chronic liver disease characterized by the accumulation of fat in the liver and hepatic steatosis, which can progress to critical conditions, including Metabolic dysfunction-associated Steatohepatitis (MASH), liver fibrosis, hepatic cirrhosis, and hepatocellular carcinoma. Galectin-3, a member of the galectin family of proteins, has been involved in cascades that are responsible for the pathogenesis and progression of liver fibrosis in MAFLD. This review summarizes the present understanding of the role of galectin-3 in the severity of MAFLD and its associated liver fibrosis. The article assesses the underlying role of galectin-3-mediated fibrogenesis, including the triggering of hepatic stellate cells, the regulation of extracellular degradation, and the modulation of immune reactions and responses. It also highlights the assessments of the potential diagnostic and therapeutic implications of galectin-3 in liver fibrosis during MAFLD. Overall, this review provides insights into the multifaceted interaction between galectin-3 and liver fibrosis in MAFLD, which could lead to the development of novel strategies for diagnosis and treatment of this prevalent liver disease.