Protein and Peptide Letters最新文献

Background: Increasing evidence proves that long non-coding RNAs (lncRNAs) play a key role in the occurrence and development of colorectal cancer. However, the function and molecular mechanism of LINC01836 in CRC are still unknown.

Methods: The differentially expressed lncRNAs in colorectal cancer were obtained from the RNA sequencing data. The effects of LINC01836 on colorectal cancer cells were tested in in vitro experiments. The mechanism of LINC01836 action was investigated through western blot, RNA immunoprecipitation assay and luciferase reporter assay. Moreover, the xenograft mouse model was conducted to examine the effects of LINC01836 in vivo.

Results: In this study, we showed that LINC01836 was significantly elevated in colorectal cancer tissues and cells. Elevated LINC01836 expression significantly correlated with larger tumor size, positive lymph node metastasis, distant metastasis, advanced tumor-node-metastasis (TNM) stage, and poor prognosis. Furthermore, decreased expression of LINC01836 repressed proliferation, migration, and invasion in vitro and vivo, and high LINC01836 expression displayed the opposite effect. Further analysis revealed that LINC01836 could regulate the expression of SLC17A9 by competing with miR---1226-3p. Furthermore, down-regulation of LINC01836 or increased expression of miR-1226-3p markedly reversed the effects of SLC17A9 overexpression on colorectal cancer cells.

Conclusion: This study showed that LINC01836 regulated the expression of SLC17A9 through sponge miR-1226-3p by acting as a competitive endogenous RNA (ceRNA), promoted the progression of colorectal cancer, and suggested a new prognostic biomarker and potential cancer treatment target for colorectal cancer.

Introduction: Parvovirus B19 (B19V) is a human pathogen, and the minor capsid protein of B19V possesses a unique N terminus called VP1u that plays a crucial role in the life cycle of the virus.

Objectives: The objective of this study was to develop a method for domain segmentation of B19 VP1u using intein technology, particularly its receptor binding domain (RBD) and phospholipase A2 (PLA₂) domain.

Methods: RBD and PLA₂ domains of VP1u were each fused to the DnaE split inteins derived from the Nostoc punctiforme. Each of these precursor proteins was expressed in E. coli. Combining the purified precursors in equal molar ratios resulted in the formation of full-length VP1u. Furthermore, Circular Dichroism (CD) spectroscopy and PLA₂ assays were used to probe the structure and activity of the newly formed protein.

Results: The CD spectrum of the full length VP1u confirmed the secondary structure of protein, while the PLA₂ assay indicated minimal disruption in enzymatic activity.

Conclusion: This method would allow for the selective incorporation of NMR-active isotopes into either of the VP1u domains, which can reduce signal overlap in NMR structural determination studies.

Background: Atopic dermatitis (AD), psoriasis (PS), and inflammatory acne (IA) are well-known as inflammatory skin diseases. Studies of the transcriptome with altered expression levels have reported a large number of dysregulated genes and gene clusters, particularly those involved in inflammatory skin diseases.

Objective: To identify genes commonly shared in AD, PS, and IA that are potential therapeutic targets, we have identified consistently dysregulated genes and disease modules that overlap with AD, PS, and IA.

Methods: Microarray data from AD, PS, and IA patients were downloaded from Gene Expression Omnibus (GEO), and identification of differentially expressed genes from microarrays of AD, PS, and IA was conducted. Subsequently, gene ontology and gene set enrichment analysis, detection of disease modules with known disease-associated genes, construction of the protein-protein interaction (PPI) network, and PPI sub-mapping analysis of shared genes were performed. Finally, the computational docking simulations between the selected target gene and inhibitors were conducted.

Results: We identified 50 shared genes (36 up-regulated and 14 down-regulated) and disease modules for each disease. Among the shared genes, 20 common genes in PPI network were detected such as LCK, DLGAP5, SELL, CEP55, CDC20, RRM2, S100A7, S100A9, MCM10, AURKA, CCNB1, CHEK1, BTC, IL1F7, AGTR1, HABP4, SERPINB13, RPS6KA4, GZMB, and TRIP13. Finally, S100A9 was selected as the target gene for therapeutics. Docking simulations between S100A9 and known inhibitors indicated several key binding residues, and based on this result, we suggested several cannabinoids such as WIN-55212-2, JZL184, GP1a, Nabilone, Ajulemic acid, and JWH-122 could be potential candidates for a clinical study for AD, PS, and IA via inhibition of S100A9-related pathway.

Conclusion: Overall, our approach may become an effective strategy for discovering new disease candidate genes for inflammatory skin diseases with a reevaluation of clinical data.

Objectives: In this study, we employed an in vitro culturing technique to investigate the impact of p53 on the modulation of growth-associated protein-43 (GAP-43) within the primary cortical neurons of rat specimens.

Methods: (1) Within the first 24 hours after birth, the bilateral cortex was extracted from newborn Wistar rats and primary cortical neurons were cultured and identified. (2) The changes in the mRNA and protein expressions of GAP-43 induced by p53 in rat primary cortical neurons cultured in vitro were identified utilizing real-time polymerase chain reaction and western blot techniques.

Results: (1) Lentiviral transfection of p53 within primary cortical neurons of rats elicited elevated levels of both mRNA and protein expressions of GAP-43, consequently culminating in a noteworthy augmentation of p53 expression. (2) The introduction of a p53 inhibitor in rat primary cortical neurons resulted in a reduction in both mRNA and protein expressions of GAP-43.

Conclusion: Within primary rat cortical neurons, p53 has the potential to prompt an augmentation in both the transcriptional and protein expression levels of the GAP-43 protein.

Background: Colorectal cancer (CRC) is a prevalent form of cancer globally, characterized by a high mortality rate. Therefore, discovering effective therapeutic approaches for CRC treatment is critical.

Methods: The levels of KIF20A in CRC clinical samples were determined using Western Blot and immunofluorescence assay. SW480 cells were transfected with siRNA targeting KIF20A, while HT-29 cells were transfected with a KIF20A overexpression vector. Cell viability and apoptosis of CRC cells were assessed using CCK-8 and TUNEL analysis. Migration ability was investigated using Transwell. The levels of pyruvate, lactate and ATP were determined through corresponding assay kits. Western Blot was applied to confirm the level of proteins associated with glycolysis, c- Myc, HIF-1α, PKM2 and LDHA. Subsequently, functional rescue experiments were conducted to investigate further the regulatory relationship between KIF20A, c-Myc, and HIF-1α in colorectal cancer (CRC), employing the c-Myc inhibitor 10058-F4 and c-Myc overexpression plasmids.

Results: KIF20A was up-regulated in vivo and in vitro in CRC. KIF20A knockdown inhibited cell viability and migration while promoting cell apoptosis in SW480 cells. Conversely, overexpression of KIF20A yielded contrasting effects in HT-29 cells. Moreover, inhibition of KIF20A restrained the pyruvate, lactate production and ATP level, whereas overexpression of KIF20A enhanced the Warburg effect. Western Blot indicated that knockdown KIF20A attenuated the levels of c-Myc, HIF-1α, PKM2 and LDHA. In addition, rescue experiments further verified that KIF20A enhanced the Warburg effect by the KIF20A/c-Myc/HIF-1α axis in CRC.

Conclusion: KIF20A, being a crucial regulator in the progression of CRC, has the potential to be a promising therapeutic target for the treatment of CRC.

Background: Staphylococcus aureus is a common pathogen with strains that are resistant to existing antibiotics. MurJ from S. aureus (SaMurJ), an integral membrane protein functioning as Lipid II flippase, is a potential target for developing new antibacterial agents against this pathogen. Successful expression and purification of this protein shall be useful in the development of drugs against this target.

Objective: In this study, we demonstrated the optimized expression and purification procedures of SaMurJ, identified suitable detergent for extracting and solubilizing the protein, and examined the peptidisc system to generate a detergent-free environment.

Methods: SaMurJ fused with N-terminal ten-His tag was expressed without induction. Six detergents were selected for screening the most efficient candidate for extraction and solubilization of the protein. The thermostability of the detergent-solubilized protein was assessed by evaluated temperature incubation. Different ratios of peptidisc bi-helical peptide (NSPr) to SaMurJ were mixed and the on-bead peptidisc assembly method was applied.

Results: SaMurJ expressed in BL21(DE3) was confirmed by peptide fingerprinting, with a yield of 1 mg SaMurJ per liter culture. DDM was identified as the optimum detergent for solubilization and the nickel affinity column enabled SaMurJ purification with a purity of ~88%. However, NSPr could not stabilize SaMurJ.

Conclusion: The expression and purification of SaMurJ were successful, with high purity and good yield. SaMurJ can be solubilized and stabilized by a DDM-containing buffer.

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.

Malaria caused by Plasmodium falciparum (Pf) is an illness that contributes significantly to the global health burden. Pf makes significant alterations to the host cell to meet its metabolic demands and escape the immune response of the host. These include the export of a large number of parasite proteins to the infected Red Blood Cells (iRBC). Variable Surface Antigens (VSAs), which are highly polymorphic protein families with important roles in immune evasion, form an important component of the exported proteins. A total of five protein families constitute the VSAs, viz. PfEMP1 (Pf erythrocyte membrane protein 1), RIFIN (repetitive interspersed family), STEVOR (sub-telomeric open reading frame), SURFIN (surface-associated interspersed gene family), and PfMC-2TM (Pf Maurer's cleft two transmembrane). With orthologues present in various simian-infecting species, VSAs take up a variety of domain topologies and organizational structures while exhibiting differential expressions throughout the parasite life cycle. Their expression varies across clinical isolates and laboratory strains, which suggests their crucial role in host cell survival and defense. Members of VSAs are reported to contribute significantly to disease pathogenesis through immune evasion processes like cytoadherence, iRBC sequestration in the host vasculature, rosetting, reduced erythrocyte deformability, and direct immunosuppression. In this study, we have gathered information on various aspects of VSAs, like their orthologues, domain architecture, surface topology, functions and interactions, and three-dimensional structures, while emphasizing discoveries in the field. Considering the vast repertoire of Plasmodial VSAs with new emergent functions, a lot remains unknown about these families and, hence, malaria biology.

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.