Recombinant Peptide Research Articles

Abstract 4138719: Effect of Recombinant Human Brain Natriuretic Peptide on Cardiac Surgery Associated Acute Kidney Injury in Patients Undergoing Coronary Artery Bypass Grafting

Backgrounds: Cardiac surgery associated acute kidney injury (CSA-AKI) is a prevalent and detrimental complication following cardiac surgery, with significant effects on both in-hospital and long-term morbidity and mortality. The effect on renal prognosis of recombinant human brain natriuretic peptide (rhBNP) for patients undergoing cardiac surgery remains unclear. Purpose: This study aims to evaluate the association between postoperative rhBNP and the risk of CSA-AKI following coronary artery bypass grafting (CABG). Methods: This retrospective cohort study included 16096 consecutive patients undergoing CABG between 2017 and 2022. The primary outcome was in-hospital postoperative AKI according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The secondary outcome was the amplitude of postoperative NT-proBNP reduction, defined as a difference value between the highest and last results during hospitalization. Multivariate Cox proportional hazards regression models and linear regression models were constructed to assess the association between perioperative statin and pre-defined outcomes. Results: A total of 9392 (58.3%) patients received postoperative rhBNP therapy, with a total of 1474 (9.2%) patients developing CSA-AKI. For the primary outcome, postoperative rhBNP was associated with a significantly increased risk of CSA-AKI (83.0% vs. 55.9%; adjusted Odds Ratio [OR], 3.615 [95% CI, 3.136-4.166]; p < 0.001). Noticeably, we found that postoperative rhBNP was also related to increased amplitude of postoperative NT-proBNP reduction, with an average of 3193.98 versus 1040.21 pg/mL (p for linear < 0.001). For the subgroup analysis, the association between postoperative rhBNP and reduced CSA-AKI risk was greater among patients with HFpEF (p for interaction = 0.087). Conclusions: Postoperative rhBNP therapy was associated with a significantly higher risk of CSA-AKI following CABG. Meanwhile, rhBNP contributed to NT-proBNP reduction postoperatively, with a more pronounced effect in patients with HFpEF.

Abstract 4140120: Artificial intelligence-driven morbidity prediction in acute kidney injury after acute type A aortic dissection surgery

Background: Acute kidney injury (AKI) often complicates acute type A aortic dissection (ATAAD), with elevated comorbidity rates and a significant tie to in-hospital mortality. Identifying risk factors early can mitigate AKI severity. Research Questions: This research endeavors to develop and corroborate predictive models leveraging Machine Learning (ML) techniques from Artificial Intelligence to forecast AKI occurrences in ATAAD-afflicted individuals. Methods: The study employed various machine learning (ML) algorithms including Gradient Boosting Machine (GBM), LightGBM, Random Forest (RF), K-Nearest Neighbors (KNN), Multi-Layer Perceptron Neural Network (MLP-NN), Naive Bayes (NB), Logistic Regression (LR), and ensemble methods (combining LR&LightGBM), employing tenfold cross-validation. Model performance was evaluated using SHapley Additive exPlanations (SHAP). A web-based tool for predicting AKI incidence was developed using Streamlit, based on the most effective model. The analysis involved 1350 ATAAD patients, among whom 586 (43.4%) developed post-operative AKI. Patients were divided into two cohorts: 85% for training and 15% for testing, with 126 features included in the predictive model. Results: Incorporating top 10 features, LightGBM (AUROC=0.886, 95% CI 0.841-0.930) excelled in predictive accuracy, calibration, and clinical utility, identifying key factors such as ventilation time in ICU, hourly urine output post-surgery, diuretic use, Scr, heart rate, urea, administration of recombinant human brain natriuretic peptide and ebrantil, MCHC, and blood glucose as associated with ATAAD-AKI. Conclusion(s): These ML models are robust tools for predicting AKI in ATAAD patients, with LightGBM's superior predictive ability standing out. They offer valuable support for clinical decision-making in ATAAD management, helping optimize postoperative strategies to minimize AKI occurrence after surgery.

The Inhibitory Effect and Mechanism of the Histidine-Rich Peptide rAj-HRP from Apostichopus japonicus on Human Colon Cancer HCT116 Cells.

Colon cancer is a common and lethal malignancy, ranking second in global cancer-related mortality, highlighting the urgent need for novel targeted therapies. The sea cucumber (Apostichopus japonicus) is a marine organism known for its medicinal properties. After conducting a bioinformatics analysis of the cDNA library of Apostichopus japonicus, we found and cloned a cDNA sequence encoding histidine-rich peptides, and the recombinant peptide was named rAj-HRP. Human histidine-rich peptides are known for their anti-cancer properties, raising questions as to whether rAj-HRP might exhibit similar effects. To investigate whether rAj-HRP can inhibit colon cancer, we used human colon cancer HCT116 cells as a model and studied the tumor suppressive activity in vitro and in vivo. The results showed that rAj-HRP inhibited HCT116 cell proliferation, migration, and adhesion to extracellular matrix (ECM) proteins in vitro. It also disrupted the cytoskeleton and induced apoptosis in these cells. In vivo, rAj-HRP significantly inhibited the growth of HCT116 tumors in BALB/c mice, reducing tumor volume and weight without affecting the body weight of the tumor-bearing mice. Western blot analysis showed that rAj-HRP inhibited HCT116 cell proliferation and induced apoptosis by upregulating BAX and promoting PARP zymogen degradation. Additionally, rAj-HRP inhibited HCT116 cell adhesion and migration by reducing MMP2 levels. Further research showed that rAj-HRP downregulated EGFR expression in HCT116 cells and inhibited key downstream molecules, including AKT, P-AKT, PLCγ, P38 MAPK, and c-Jun. In conclusion, rAj-HRP exhibits significant inhibitory effects on HCT116 cells in both in vitro and in vivo, primarily through the EGFR and apoptosis pathways. These findings suggest that rAj-HRP has the potential as a novel targeted therapy for colon cancer.

Levosimendan improves the early prognosis of patients with Non ST-segment elevation myocardial infarction and Killip class > II

Abstract Background Levosimendan is an inotropic agent known for its calcium-sensitizing myofilament effect and ATP-dependent potassium channel opening mechanism, which enhances myocardial contractility without increasing oxygen consumption. Despite its potential benefits, the impact of levosimendan on the prognosis of patients with myocardial infarction remains uncertain and requires further investigation through larger-scale studies. Purpose This study aimed to investigate the effect of levosimendan on the short-term prognosis of patients with Non-ST-segment elevation myocardial infarction (NSTEMI) and Killip> II. Methods The data for this study were derived from the Health and Medical Big Data Superplatform, comprising a retrospective cohort of patients admitted to and discharged from 72 secondary and tertiary hospitals in the City from 2010 to 2023. A total of 12472 patients with NSTEMI and Killip > II were included. Patients were divided into the levosimendan group and the non-leosimendan group based on whether levosimendan was used during hospitalization. Propensity score matching (PSM) was employed to balance covariates between the two groups. Multivariate Cox regression was used to evaluate the relationship between levosimendan and clinical outcomes. Covariates adjusted in PSM included age, sex, Killip class, early PCI, previous PCI, previous medical conditions (diabetes, hypertension, ischemic stroke, and chronic kidney disease), and medications during hospitalization (aspirin, clopidogrel, indobufen, ticagrelor, statins, cedilanid, recombinant human brain natriuretic peptide [rhBNP], milrinone, dopamine, dobutamine, and angiotensin converting enzyme inhibitor/angiotensin receptor blockers [ACEI/ARB]). The primary endpoint was major cardiovascular and cerebrovascular adverse events (MACCE), defined as the composite endpoint of cardiac death, myocardial infarction, and ischemic stroke within 3 months. Results The levosimendan group comprised 782 patients, while the non-leosimendan group included 11690 patients. After PSM, the covariates were balanced, resulting in 756 well-matched pairs. In PSM patients, the levosimendan group exhibited a significantly lower incidence of MACCE (aHR, 0.573; 95%CI, 0.466–0.704; p < 0.001) and cardiac death (aHR, 0.500; 95%CI, 0.399-0.626; p < 0.001). However, there was no significant difference in the incidence of myocardial infarction and ischemic stroke. Conclusions Levosimendan was associated with a lower incidence of MACCE within 3 months in patients with NSTEMI and Killip> II, mainly driven by lower incidence of cardiac death. However, these findings are based on observational data and require confirmation through adequately powered, randomized, controlled trials.

Secretion of the human parathyroid hormone through a microcin type I secretion system in Escherichia coli

BackgroundGram negative bacteria possess different secretion systems to export proteins to the extracellular medium. The simplest one, type I secretion system (T1SS), forms a channel across the cell envelope to export proteins in a single step. Peptides secreted by the T1SSs comprise a group of antibiotics, called class II microcins, which carry an amino terminal secretion domain that is processed concomitantly with export. Mature microcins range in size from 60 to 90 amino acids and differ in their sequences. Microcin T1SSs show a high versatility in relation to the peptides they are able to secrete, being mainly limited by the length of the substrates. Different bioactive peptides unrelated to bacteriocins could be secreted by microcin V (MccV) T1SS, while retaining their biological activity.ResultsIn this work heterologous secretion of two variants of human parathyroid hormone (PTH) by MccV T1SS was evaluated. PTH is a bioactive peptide of 84 amino acids (PTH84), which is involved in the maintenance of bone homeostasis. Currently, a drug corresponding to the active fraction of the hormone, which resides in its first 34 amino acids (PTH34), is commercially produced as a recombinant peptide in Escherichia coli. However, research continues to improve this recombinant production. Here, gene fusions encoding hybrid peptides composed of the MccV secretion domain attached to each hormone variant were constructed and expressed in the presence of microcin T1SS in E. coli cells. Both PTH peptides (PTH34 and PTH84) were recovered from the culture supernatants and could be confirmed to lack the MccV secretion domain, i.e. microcin T1SS efficiently recognised, processed and secreted both PTH variants. Furthermore, the secreted peptides were stable in the extracellular medium unlike their unprocessed counterparts present in the intracellular space.ConclusionThe successful secretion of PTH variants using MccV T1SS could be considered as a new alternative for their production, since they would be recovered directly from the extracellular space without additional sequences. Furthermore, it would be a new example revealing the potential of microcin type I secretion systems to be conceived as a novel strategy for the production of recombinant peptides in E. coli.

Monitoring for PERV Following Xenotransplantation.

Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pigs. PERV-A, PERV-B and PERV-C can be released as infectious virus particles and PERV-A and PERV-B can infect human cells in culture. PERV-C does not infect human cells, but high-titer recombinant PERV-A/C can infect them. Retroviruses are able to induce immunosuppression and/or tumors in the infected host. Numerous methods have been developed to study PERV in donor pigs. No PERV infections were observed in infection experiments as well as in preclinical and clinical xenotransplantation trials. Despite this, several strategies have been developed to prevent PERV infection of the recipient. PCR-based and immunological methods are required to screen xenotransplant recipients. Since the proviruses are integrated into the pig genome, PERV infection has to be distinguished from microchimerism, e.g., the presence of pig cells in the recipient, which is common in xenotransplantation. Sensitive PCR methods using pig short interspersed nuclear elements (SINE) sequences allow to detect pig cells easily. Virus infection can also be detected by an increase of viral genomic or mRNA in human cells. The method of choice, however, is to screen for specific antibodies against PERV using different recombinant PERV proteins, purified viruses or peptides.

Expression of a novel NaD1 recombinant antimicrobial peptide enhances antifungal and insecticidal activities

This study aimed to increase the antifungal and insecticidal activities of NaD1, as an antimicrobial peptides (AMP), by improving its interaction with the fungal cell wall and chitin monomeric units in insect midguts. Hence, the chitin-binding domains (CBDs) of wheat germ agglutinin protein (WGA) were fused to either N- or C-terminus of NaD1 generating transgenic Nicotiana tabacum hairy roots (HRs). Molecular assessments confirmed the integration of NaD1 transgenes, their transcription and production of recombinant peptides in the HR lines. Total protein of (CBD)4-NaD1 and NaD1-(CBD)4 transgenic lines inhibited the growth of Pyricularia oryzae mycelium, suggesting that fusion of CBD to NaD1 can increase NaD1 half-life, leading to higher affinity toward cell wall chitin. Furthermore, feeding the third-instar larvae of Chilo suppressalis with both (CBD)4-NaD1 and NaD1-(CBD)4 extracts exhibited a higher mortality rate. Both NaD1-CBDs caused a significant decrease in trypsin (TRY) and chymotrypsin (CTR) activities in the larvae, while enhancing the activity of antioxidant enzymes CAT, POD, APX, and SOD. Therefore, feeding the larvae by total extract of NaD1-(CBD)4 and (CBD)4-NaD1 HR lines probably increased affinity to midgut chitin in C. suppressalis, enhancing insecticidal activities. Overall, the results indicate that recombinant peptides are effective in enhancing fungal and insect resistance.

A study on loading multiple epitopes with a single peptide.

Epitopes, the basic functional units of antigens, hold great significance in the field of immunology. However, the structure and composition of epitopes and their interactions with antibodies remain unclear, which limits in-depth studies on epitopes and the development of subunit vaccines. In a previous study on the localization of anti-influenza HA monoclonal antibodies (mAbs), three strains with different characteristics reacted with the same peptide. In this study, by conventional immunological assays, computer homology modeling, and molecular docking simulations, we found that (1) the peptide could bind to three strains of mAbs with different reaction characteristics utilizing different combinations of immunodominant groups. (2) By computer molecular docking and simulation methods, the immunodominant groups on the two peptides could be combined into a multi-epitope peptide bound to six strains of mAbs. We established a method for multi-epitope peptide recombination from these immunodominant groups. (3) The immune effect of the recombinant multi-epitope peptide was better than that of a single peptide. Our findings facilitate the understanding of the composition of antigen epitopes and provide a theoretical and experimental basis for developing polyvalent vaccines and understanding immune responses at the molecular level.

Clinical effect of recombinant human brain natriuretic peptide in the treatment of heart failure in elderly patients

BackgroundHeart failure in elderly individuals poses significant challenges due to the decline in cardiac function associated with aging. This study aimed to investigate the clinical efficacy of recombinant human brain natriuretic peptide (rhBNP) for the treatment of heart failure, especially in elderly patients.MethodsThis was a retrospective case control study of the medical records of 60 elderly patients with heart failure admitted to our hospital between December 2020 and December 2023. Patients were divided into two groups based on treatment. The control group (n = 30) received diuretics, digitalis, and β receptor blockers, while the observation group (n = 30) received lyophilized rhBNP in addition to the control group treatment. Changes in BNP levels and clinical outcomes were compared between the two groups.ResultsPosttreatment BNP levels were significantly lower in the observation group than in the control group (p < 0.05), and the total clinical effective rate was greater in the observation group (p < 0.05). Additionally, the left ventricular diameter, left atrial diameter, left ventricular shortening fraction, diastolic flow signal and cardiac output in the observation group were lower than those in the control group (p < 0.05), while the thickness of the aortic root diameter in the observation group was greater than that in the control group (p < 0.05).ConclusionRhBNP demonstrated ideal clinical efficacy in elderly patients with heart failure, improving symptoms and indicating potential for widespread use in the future.

Biochemical Characterization of Recombinant Enterococcus faecalis EntV Peptide to Elucidate Its Antihyphal and Antifungal Mechanisms against Candida albicans.

Candida albicans is a common opportunistic fungus in humans, whose morphological switch between yeast and hyphae forms represents a key virulence trait. Developing strategies to inhibit C. albicans hyphal growth may provide insights into designs of novel antivirulent therapeutics. Importantly, the gut commensal bacterium, Enterococcus faecalis, secretes a bacteriocin EntV which has potent antivirulent and antifungal effects against C. albicans in infection models; however, hampered by the challenges to access large quantities of bioactive EntV, the detailed understanding of its mechanisms on C. albicans has remained elusive. In this work, we biochemically reconstituted the proteolytic cleavage reaction to obtain recombinant EntV88-His6 on a large preparative scale, providing facile access to the C-terminal EntV construct. Under in vitro C. albicans hyphal assay with specific inducers, we demonstrated that EntV88-His6 exhibits potent bioactivity against GlcNAc-triggered hyphal growth. Moreover, with fluorescent FITC-EntV88-His6, we revealed that EntV88-His6 enters C. albicans via endocytosis and perturbs the proper localization of the polarisome scaffolding Spa2 protein. Our findings provide important clues on EntV's mechanism of action. Surprisingly, we showed that EntV88-His6 does not affect C. albicans yeast cell growth but potently exerts cytotoxicity against C. albicans under hyphal-inducing conditions in vitro. The combination of EntV88-His6 and GlcNAc displays rapid killing of C. albicans, rendering it a promising antivirulent and antifungal agent.

Agonist antibody to guanylate cyclase receptor NPR1 regulates vascular tone

Heart failure is a leading cause of morbidity and mortality1,2. Elevated intracardiac pressures and myocyte stretch in heart failure trigger the release of counter-regulatory natriuretic peptides, which act through their receptor (NPR1) to affect vasodilation, diuresis and natriuresis, lowering venous pressures and relieving venous congestion3–8. Recombinant natriuretic peptide infusions were developed to treat heart failure but have been limited by a short duration of effect9,10. Here we report that in a human genetic analysis of over 700,000 individuals, lifelong exposure to coding variants of the NPR1 gene is associated with changes in blood pressure and risk of heart failure. We describe the development of REGN5381, an investigational monoclonal agonist antibody that targets the membrane-bound guanylate cyclase receptor NPR1. REGN5381, an allosteric agonist of NPR1, induces an active-like receptor conformation that results in haemodynamic effects preferentially on venous vasculature, including reductions in systolic blood pressure and venous pressure in animal models. In healthy human volunteers, REGN5381 produced the expected haemodynamic effects, reflecting reductions in venous pressures, without obvious changes in diuresis and natriuresis. These data support the development of REGN5381 for long-lasting and selective lowering of venous pressures that drive symptomatology in patients with heart failure.

Enhanced Production and Therapeutic Evaluation of TP4 Peptide in Pichia pastoris Against Hepatocellular Carcinoma HUH-7 Cells

Tilapia piscidin 4 (TP4), a cationic antimicrobial peptide, is recognized for its diverse biological roles, including antibacterial, wound-healing, and anticancer properties. Herein, the codon-optimized sequence of TP4 peptide was expressed using the pPICZαA expression vector containing the AOX1 promoter, a strong and inducible promoter, in the Pichia pastoris KM71H expression system. Recombinant TP4 peptide was purified by Ni-NTA affinity chromatography. After purification, the anticancer activity of TP4 was assessed in HUH-7 hepatocellular carcinoma cells, and the underlying mechanisms were determined. In the present study, it was demonstrated for the first time that recombinant TP4 displayed strong anticancer activity in the human HUH-7 cell line. The TP4 antimicrobial peptide can be used as a competitive candidate for the treatment of cancer cells due to its anticancer effects.

Benefits of recombinant human brain natriuretic peptide to improve ventricular function and hemodynamics in patients with ST-elevation myocardial infarction.

Abstract. This study aimed to assess the impact of recombinant human brain natriuretic peptide (rh-BNP) on ventricular function and hemodynamics in post-ST-segment elevation myocardial infarction (STEMI). We compared the outcomes of 65 STEMI patients treated with rh-BNP to an equal cohort given tirofiban following percutaneous coronary intervention (PCI). Data collected pre- and post-intervention included biochemical markers, TIMI (Thrombolysis In Myocardial Infarction) grade, hemodynamics, thrombotic score (TS), left ven-tricular ejection fraction (LVEF), high-sensitivity C-reactive protein (CRP) levels, liver and kidney function, and ECG. The TIMI level (p=0.03), the ratio of TIMI myocardial perfusion grade III (p=0.04), and the thrombus score (p&lt;0.001) in the rh-BNP group after the intervention markedly exceeded those in the tirofiban group. After correction, the TIMI frame count (CTFC) (p=0.02), the incidence of slow flow (p=0.02), thrombus score (p&lt;0.001), stent length (p=0.02) as well as times of administration of sodium nitroprusside medication in the rh-BNP group were markedly below those in the tirofiban group (p=0.01). Creatine ki-nase (CK) (p&lt;0.001), CK-MB (p=0.01), and N-terminal pro-b-type natriuretic peptide (NT-proBNP) (p&lt;0.02) in the rh-BNP group were markedly below those the in tirofiban group 24 hours after intervention; and the sum-STR (p&lt;0.03) immediately after intervention markedly exceeded that in the tirofiban group. No significant differences were found in major cardiac adverse events (MACE) between the treatments. At the 30-day follow-up, rh-BNP showed a more effective enhancement of blood flow status, with the safety profiles of both treatments be-ing comparable. The findings suggest that the rh-BNP has significant potential for treating PPCI-related slow flow.

Does rAj-Tspin, a novel peptide from A. japonicus, exert antihepatocellular carcinoma effects via the ITGB1/ZYX/FAK/AKT signaling pathway?

rAj-Tspin, a soluble recombinant peptide from Apostichopus japonicus, can inhibit the integrin β1 (ITGB1)/FAK/AKT signaling pathway in hepatocellular carcinoma (HCC) via cell epithelial–mesenchymal transition (EMT) and apoptosis. Zyxin (ZYX) is a focal adhesion protein that is considered a novel mediator of EMT and apoptosis. However, the inhibitory mechanisms of rAj-Tspin in HCC and whether it is related to ZYX are unclear. We examined the antitumor effect of rAj-Tspin on the Huh7 human HCC cell line and on a nude mouse model generated via subcutaneous injection or orthotopic intrahepatic transplantation of Huh7 cells. Our results revealed that rAj-Tspin strikingly reduced the viability and promoted the apoptosis of Huh7 cells and inhibited HCC tumor growth in nude mice. rAj-Tspin inhibited ITGB1 and ZYX protein expression in vivo and in vitro in a dose-dependent manner. Mechanistically, the FAK/AKT signaling pathway and the proliferation and invasion of HCC cells were suppressed upon ITGB1 and ZYX knockdown. Moreover, the effect of ITGB1 overexpression on the growth of HCC cells was inhibited by rAj-Tspin. In contrast, the promoting effect of ITGB1 overexpression could be inhibited by ZYX knockdown. ZYX knockdown had no effect on ITGB1 expression. These findings suggest that ZYX is required for the indispensable role of ITGB1 in rAj-Tspin‐alleviated HCC and provide an important therapeutic target for HCC. In summary, the anti-HCC effect of rAj-Tspin potentially involves the regulation of the ITGB1/ZYX/FAK/AKT pathway, which in turn impacts EMT and apoptosis.Graphical

Entamoeba histolytica: EhADH, an Alix Protein, Participates in Several Virulence Events through Its Different Domains.

Entamoeba histolytica is the protozoan causative of human amoebiasis. The EhADH adhesin (687 aa) is a protein involved in tissue invasion, phagocytosis and host-cell lysis. EhADH adheres to the prey and follows its arrival to the multivesicular bodies. It is an accessory protein of the endosomal sorting complexes required for transport (ESCRT) machinery. Here, to study the role of different parts of EhADH during virulence events, we produced trophozoites overexpressing the three domains of EhADH, Bro1 (1-400 aa), Linker (246-446 aa) and Adh (444-687 aa) to evaluate their role in virulence. The TrophozBro11-400 slightly increased adherence and phagocytosis, but these trophozoites showed a higher ability to destroy cell monolayers, augment the permeability of cultured epithelial cells and mouse colon, and produce more damage to hamster livers. The TrophozLinker226-446 also increased the virulence properties, but with lower effect than the TrophozBro11-400. In addition, this fragment participates in cholesterol transport and GTPase binding. Interestingly, the TrophozAdh444-687 produced the highest effect on adherence and phagocytosis, but it poorly influenced the monolayers destruction; nevertheless, they augmented the colon and liver damage. To identify the protein partners of each domain, we used recombinant peptides. Pull-down assays and mass spectrometry showed that Bro1 domain interplays with EhADH, Gal/GalNAc lectin, EhCPs, ESCRT machinery components and cytoskeleton proteins. While EhADH, ubiquitin, EhRabB, EhNPC1 and EhHSP70 were associated to the Linker domain, and EhADH, EhHSP70, EhPrx and metabolic enzymes interacted to the Adh domain. The diverse protein association confirms that EhADH is a versatile molecule with multiple functions probably given by its capacity to form distinct molecular complexes.

Identification of Immunodominant Epitopes of Dengue Virus 2 Envelope and NS1 Proteins: Evaluating the Diagnostic Potential of a Synthetic Peptide.

Dengue is a major infectious disease with potential for outbreaks and epidemics. A specific and sensitive diagnosis is a prerequisite for clinical management of the disease. We designed our study to identify epitopes on theDengue virus (DENV) envelope (E) and non-structural protein 1 (NS1) with potential for diagnosis. Serology and immunoinformatic approaches were employed. We collected DENV-positive, DENV-negative and Japanese encephalitis virus-positive samples from collaborating hospitals in 2019 and 2022-2023. Seropositive peptides in 15-18 mer peptide arrays of E and NS1 proteins of DENV2 were determined by an indirect enzyme-linked immunosorbent assay. B-cell linear and conformational epitopes were predicted using BepiPred2.0 and ElliPro, respectively. A consensus recombinant peptide was designed, synthesised and evaluated for its diagnostic potential using patient sera. Eight peptides of E protein and six peptides of NS1 protein were identified to be the most frequently recognised by Dengue-positive patients. These peptide sequences were compared with B-cell epitope regions and found to be overlapped with predicted B-cell linear and conformational epitopes. EP11 and NSP15 showed a 100% amino acid sequence overlap with B-cell epitopes. EP1 and NSP15 had 14 whereas EP28, EP31, EP60 16, NSP12 and NSP32 had more than 15 interacting interface residues with a neutralising antibody, suggesting a strength of interaction. Interestingly, potential epitopes identified were localised on the surface of proteins as visualised by PyMOL. Validation with a recombined synthetic peptide yielded 92.3% sensitivity and 91.42% specificity. Immunodominant regions identified by serology and computationally predicted epitopes overlapped, thereby showing the robustness of the methodology and the peptide designedfor diagnosis.

Cobalt Oxide Nanoparticle Synthesis by Cell-Surface-Engineered Recombinant Escherichia coli and Potential Application for Anticancer Treatment.

Cell surface display engineering facilitated the development of a cobalt-binding hybrid Escherichia coli. OmpC served as the molecular anchor for showcasing the cobalt-binding peptides (CBPs), creating the structural model of the hybrid OmpC-CBPs (OmpC-CP, OmpC-CF). Subsequently, the recombinant peptide's cobalt adsorption and retrieval effectiveness were evaluated at various concentrations. When subjected to a pH of 7 and a concentration of 2 mM, OmpC-CF exhibited a significantly higher cobalt recovery rate (2183.87 mol/g DCW) than OmpC-CP. The strain with bioadsorbed cobalt underwent thermal treatment at varying temperatures (400 °C, 500 °C, 600 °C, and 700 °C) and morphological characterization of the thermally decomposed cobalt nanoparticle oxides using diverse spectroscopy techniques. The analysis showed that nanoparticles confined themselves to metal ions, and EDS mapping detected the presence of cobalt on the cell surface. Finally, the nanoparticles' anticancer potential was assessed by subjecting them to heating at 500 °C in a furnace; they demonstrated noteworthy cytotoxicity, as evidenced by IC50 values of 59 μg/mL. These findings suggest that these nanoparticles hold promise as potential anticancer agents. Overall, this study successfully engineered a recombinant E. coli capable of efficiently binding to cobalt, producing nanoparticles with anticancer properties. The results of this investigation could have significant implications for advancing novel cancer therapies.

Antibacterial Efficacy and Mechanisms of Action of a Novel Beta-Defensin from Snakehead Murrel, Channa striata.

Beta-defensins, identified from fishes, constitute a crucial category of antimicrobial peptides important in combating bacterial fish pathogens. The present investigation centers on the molecular and functional characterization of CsDef, a 63-amino acid beta-defensin antimicrobial peptide derived from snakehead murrel (Channa striata). The physicochemical attributes of CsDef align with the distinctive characteristics observed in AMPs. CsDef was recombinantly produced, and the recombinant peptide, rCsDef, exhibited notable antibacterial efficacy against bacterial fish pathogens with an MIC of 16μM for V. proteolyticus. A. hydrophila exhibited 91% inhibition, E. tarda 92%, and V. harveyi 53% at 32μM of rCsDef. The rCsDef exhibited a multifaceted mechanism of action against bacteria, i.e., through membrane depolarization, membrane permeabilization, and generation of ROS. The rCsDef was non-hemolytic to hRBCs and non-cytotoxic to normal mammalian cell line CHO-K1. However, it exhibited anticancer properties in MCF-7. rCsDef demonstrated notable stability with respect to pH, temperature, salt, metal ions, and proteases. These findings suggest it is a potential candidate molecule for prospective applications in aquaculture.

Green algae-produced multimer cathelicidin-RC1 disrupts membrane integrity for inhibiting bacterial growth

Cathelicidin-RC1, extracted from the bullfrog Rana catesbeiana, has been found to effectively combat gram-negative bacteria but has limited inhibitory effects on gram-positive bacteria. Additionally, the specific mechanism of cathelicidin-RC1’s interaction with bacteria remains unclear. In this research, we present the expression analysis of a chimeric peptide composed of three repetitive units of cathelicidin-RC1 (3×cathelicidin-RC1) with a hemagglutinin (HA) and a 6×His tag attached at its C-terminus in Chlamydomonas reinhardtii, leading to the production of a chimeric peptide with a molecular mass of ∼16.2 kDa. The recombinant peptide, 3×cathelicidin-RC1-HA-6×His, demonstrates a wide range of antimicrobial activity, with minimum inhibitory concentration (MIC) values of approximately 20–30 µg/ml and 10–60 µg/ml against gram-positive and negative bacteria, respectively. The minimum bactericidal concentration (MBC) values of 3×cathelicidin-RC1-HA-6×His varies from 1× to 3×MIC. Furthermore, 3×cathelicidin-RC1-HA-6×His demonstrates excellent stability, pH stability, and resistance to digestion by certain proteases. It also exhibits low cytotoxicity and negligible hemolytic activity against rat erythrocytes. Scanning electron microscopy and propidium iodide analysis indicate that 3×cathelicidin-RC1-HA-6×His disrupts bacterial cell membranes, leading to inhibition of bacterial growth. Overall, our findings demonstrate that 3×cathelicidin-RC1-HA-6×His, produced in the heterologous expression host C. reinhardtii, effectively inhibits bacterial growth and holds great promise for potential application.

The effect of ADAMTS13 on graft-versus-host disease.

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) can potentially cure malignant blood disorders and benign conditions such as haemoglobinopathies and immunologic diseases. However, allo-HSCT is associated with significant complications. The most common and debilitating among them is graft-versus-host disease (GVHD). In GVHD, donor-derived T cells mount an alloimmune response against the recipient. The alloimmune response involves several steps, including recognition of recipient antigens, activation and proliferation of T cells in secondary lymphoid organs, and homing into GVHD-targeted organs. Adhesion molecules on T cells and endothelial cells mediate homing of T cells into lymphoid and non-lymphoid tissues. In this study, we showed that Von Willebrand factor (VWF), an adhesion molecule secreted by activated endothelial cells, plays an important role in mouse models of GVHD. We investigated the effect of the VWF-cleaving protease ADAMTS13 on GVHD. We found that ADAMTS13 reduced the severity of GVHD after bone marrow transplantation from C57BL6 donor to BALB/C recipient mice. A recombinant VWF-A2 domain peptide also reduced GVHD in mice. We showed that ADAMTS13 and recombinant VWF-A2 reduced the binding of T cells to endothelial cells and VWF invitro, and reduced the number of T cells in lymph nodes, Peyer's patches and GVHD-targeted organs invivo. We identified LFA-1 (αLβ2) as the binding site of VWF on T cells. Our results showed that blocking T-cell homing by ADAMTS13 or VWF-A2 peptide reduced the severity of the GVHD after allo-HSCT, a potentially novel method for treating and preventing GVHD.