Precursor Peptide Research Articles

The Triceptide Maturase OscB Catalyzes Uniform Cyclophane Topology and Accepts Diverse Gly-Rich Precursor Peptides.

Triceptides are a class of ribosomally synthesized and post-translationally modified peptides defined by an aromatic C(sp2) to Cβ(sp3) bond. The Gly-rich repeat family of triceptide maturases (TIGR04261) are paired with precursor peptides (TIGR04260) containing a Gly-rich core peptide. These maturases are prevalent in cyanobacteria and catalyze cyclophane formation on multiple Ω1-X2-X3 motifs (Ω1 = Trp and Phe) of the Gly-rich precursor peptide. The topology of the individual rings has not been completely elucidated, and the promiscuity of these enzymes is not known. In this study, we characterized all the cyclophane rings formed by the triceptide maturase OscB and show the ring topology is uniform with respect to the substitution at Trp-C7 and the atropisomerism (planar chirality). Additionally, the enzyme OscB demonstrated substrate promiscuity on Gly-rich precursors and can accommodate a diverse array of engineered sequences. These findings highlight the versatility and implications for using OscB as a biocatalyst for producing polycyclophane-containing peptides for biotechnological applications.

Biocompatible Synthesis of Macrocyclic Thiazol(in)e Peptides.

Macrocyclic peptides containing a thiazole or thiazoline in the backbone are considered privileged structures in both natural compounds and drug discovery, owing to their enhanced bioactivity, stability, and permeability. Here, we present the biocompatible synthesis of macrocyclic peptides from N-terminal cysteine and C-terminal nitrile. While the N-terminal cysteine is incorporated during solid-phase peptide synthesis, the C-terminal nitrile is introduced during cleavage with aminoacetonitrile, utilizing a cleavable benzotriazole linker. This method directly yields the fully functionalized linear peptide precursor. The biocompatible cyclization reaction occurs in buffer at physiological pH and room temperature. The resulting thiazoline heterocycle remains stable in buffer but hydrolyzes under acidic conditions. While such hydrolysis enables access to macrocyclic peptides with a complete amide backbone, mild oxidation of the thiazoline leads to the stable thiazole macrocyclic peptide. While conventional oxidation strategies involve metals, we developed a protocol simply relying on alkaline salt and air. Therefore, we offer a rapid and metal-free pathway to macrocyclic thiazole peptides, featuring a biocompatible key cyclization step.

Analysis of clinical features and prognostic factors in Takayasu arteritis involving pulmonary hypertension: A retrospective study.

Multiple takayasu arteritis (TA) is a chronic nonspecific large to medium vasculitis disease that mainly accumulates the aorta and its branches. Pulmonary vascular disease is often seen as stenosis and occlusion, and patients may show no moderate to severe pulmonary hypertension (PH). This study aims to summarize the clinical characteristics and analysis of prognostic factors in patients with PH caused by TA. Patients diagnosed with aortitis involving the pulmonary artery by pulmonary arteriography or pulmonary artery and total aortic computed tomography arteriography (CTA). All patients underwent detailed clinical assessment, laboratory data collection, and analysis of imaging data. Patients were followed up and factors affecting the prognosis of the pulmonary arteries were analyzed. Most of the patients' complaints were chest tightness, shortness of breath, decreased activity tolerance, hemoptysis and chest pain. 56.90% of the patients were in at the time of admission. Echocardiographic estimation of pulmonary artery systolic pressure was 90.39 ± 22.87 mm Hg. In terms of laboratory tests, 39.66%% of the patients had elevated C-reactive protein and erythrocyte sedimentation rate, and amino-terminal natriuretic peptide precursor on admission. In terms of imaging, all patients had pulmonary artery involvement, which was combined with aortic involvement in 31.03%. Nuclide lung perfusion/ventilation imaging of the patients revealed multiple perfusion defects/absences in the segmental and subsegmental distribution of the lungs. Univariate Cox regression model analysis suggested that patients' WHO functional class at admission, age ≧ 51 years at the time of consultation, and amino-terminal natriuretic peptide precursor ≧ 3500 pg/mL were factors affecting the prognosis. Further multifactorial Cox regression model analysis suggested amino-terminal natriuretic peptide precursor ≧ 3500 pg/mL was an independent predictor of poor prognosis with a hazard ratio (HR) value of 5.248. Electrocardiogram and echocardiogram may suggest an increased right heart load; some patients have elevated serum inflammatory indexes. Characteristic imaging manifestations include widening of the main pulmonary artery, multiple pulmonary segmental and subsegmental stenoses.

Using LanM Enzymes to Modify Glycagon-Like Peptides 1 and 2 in E.coli.

Selective modification of peptides is often exploited to improve pharmaceutically relevant properties of bioactive peptides like stability, circulation time, and potency. In Nature, natural products belonging to the class of ribosomally synthesized and post-translationally modified peptides (RiPPs) are known to install a number of highly attractive modifications with high selectivity. These modifications are installed by enzymes guided to the peptide by corresponding leader peptides that are removed as the last step of biosynthesis. Here, we exploit leader peptides and their matching enzymes to investigate the installation of D-Ala post-translationally in a critical position in the hormones, glucagon-like peptides (GLP) 1 and 2. We also offer insight into how precursor peptide design can modulate the modification pattern achieved.

Discovery of Borosin Catalytic Strategies and Function through Bioinformatic Profiling.

Borosins are ribosomally synthesized and post-translationally modified peptides (RiPPs) containing backbone α-N-methylations. These modifications confer favorable pharmacokinetic properties including increased membrane permeability and resistance to proteolytic degradation. Previous studies have biochemically and bioinformatically explored several borosins, revealing (1) numerous domain architectures and (2) diverse core regions lacking conserved sequence elements. Due to these characteristics, large-scale computational identification of borosin biosynthetic genes remains challenging and often requires additional, time-intensive manual inspection. This work builds upon previous findings and updates the genome-mining tool RODEO to automatically evaluate borosin biosynthetic gene clusters (BGCs) and identify putative precursor peptides. Using the new RODEO module, we provide an updated analysis of borosin BGCs identified in the NCBI database. From our data set, we bioinformatically predict and experimentally characterize a new fused borosin domain architecture, in which the modified natural product core is encoded N-terminal to the methyltransferase domain. Additionally, we demonstrate that a borosin precursor peptide is a native substrate of shewasin A, a reported aspartyl peptidase with no previously identified substrates. Shewasin A requires post-translational modification of the leader peptide for proteolytic maturation, a feature not previously observed in RiPPs. Overall, this work provides a user-friendly and open-access tool for the analysis of borosin BGCs and we demonstrate its utility to uncover additional biosynthetic strategies within the borosin class of RiPPs.

Application Value of NLR, PLR, LMR, HEART score, and POCT in Early Warning and Accurate Graded Diagnosis of High-Risk Chest Pain in Emergency Medicine

Objective: To evaluate the application value of neutrophils/lymphocytes (NLR), platelets/lymphocytes (PLR), lymphocytes/monocytes (LMR), HEART (history, electrocardiogram, age, risk factors, and troponin) score, and point-of-care testing (POCT) in the early warning and precise diagnosis of high-risk chest pain in emergency medicine. Methods: A total of 157 patients with acute chest pain who were admitted to the emergency department and chest pain treatment unit of our hospital between August 2022 and September 2023 were selected. Rapid testing of bedside myocardial markers (ultrasensitive troponin (hs-cTnI), myoglobin (MYO), creatine kinase isoenzyme (CK-MB), D-dimer (D-Dimer), and N-terminal B-type natriuretic peptide precursor (NT-proBNP)) was performed on the patients using a POCT device (ThermoKing BioMQ60proB). A HEART score was used to classify the patients into low (n = 53), intermediate (n = 59), and high-risk (n = 45) groups, and the NLR, PLR, and LMR were calculated. The NLR, PLR, and LMR values were compared among the three groups of patients, and the optimal cutoff values as well as sensitivity and specificity were determined based on receiver operating characteristic (ROC) analysis. Results: The HEART scores of patients in the low-risk, intermediate-risk, and high-risk groups were (2.72 ± 0.24), (4.75 ± 0.56), and (5.32 ± 0.73) respectively, and the differences were statistically significant (P < 0.05). Compared with the low-risk group, the intermediate-risk group and high-risk group had a significantly higher NLR and PLR, and a significantly lower LMR; the high-risk group had higher NLR and PLR and lower values of LMR as compared to the other two groups, and the difference was statistically significant (P < 0.05). The ROC curves suggested that the area under the curve, sensitivity, and specificity of the combined diagnosis of NLR, PLR, LMR, HEART score, and POCT were greater than those of LR, PLR, and LMR with HEART score and POCT alone. Conclusion: The combined application of NLR, PLR, LMR, HEART score, and POCT has significant application value in the early warning and precise diagnosis of emergency high-risk chest pain. It provides a more simple, easy-to-access, and efficient assessment index for the clinical prediction and treatment of emergency high-risk chest pain.

Novel Leptin-Cardiac TRH pathway responsible for the cardiac alterations in the Hyperleptinemic obesity.

The association between hypertension andobesity-induced cardiac damage is usually accepted.However, no studies have been focused on cardiac alterations in obesity, independently of blood pressure increase. It iswell known that Cardiac TRH induces Left Ventricular Hypertrophy (LVH) and fibrosis, and its inhibition prevents the development ofhypertrophy. Also, it has been described that the adiponectin leptin induces TRH expression. Thus, we hypothesized that in obesity, the increase in TRH induced by hyperleptinemia is responsible for LVH, until now mostly attributed to pressure load. We studied obese Agouti mice suffering from hypertension with hyperleptinemia and found a significant LVH development with increased TRH gene expression. Consequently, we found higher fibrotic (collagens and TGF-β) and hypertrophic markers (BNP and β-MHC) expressionvs lean black controls. As pressure could explain these results, we treated obese mice with diuretic (hydrochlorothiazide 20mg/kg/day) since weaning. Diuretic treatment was successful as the diuretic group was normotensive in contrast to control obese mice. Nevertheless, both groups showed LVH development, higher cardiac precursor TRH gene and peptide expressions and elevated fibrotic and hypertrophic markers expression,pointing out that obesity-induced LVH is not due to hypertension. In addition, we performed Cardiac TRH inhibition by specific siRNA injection compared to control siRNA treatment and evaluated cardiac damage. As expected, expressions and protein increase in hypertrophic and fibrotic markers observed in the AG mouse with the native cTRH system were not seen in the AG mouse with the cTRH silencing. Indeed, the AG + TRH-siRNA group showed hypertrophicmarkers expression and fibrosis measurements similar to the lean BL mice. On the whole, these results point out that the novel Leptin-Cardiac TRH pathway is responsible for the cardiac alterations present in hyperleptinemic obesity, independent of blood pressure, and cTRH long-term silencing since early stages totally preventLVH development and cardiac fibrosis.

Prediction model for developing neuropsychiatric systemic lupus erythematosus in lupus patients.

This study aimed to construct a predictive model for assessing the risk of development of neuropsychiatric systemic lupus erythematosus (NPSLE) among patients with SLE based on clinical, laboratory, and meteorological data. A total of 2232 SLE patients were included and were randomly assigned into training and validation sets. Variables such as clinical and laboratory data and local meteorological data were screened by univariate and least absolute shrinkage and selection operator (LASSO) logistic regression modelling. After 10-fold cross-validation, the predictive model was built by multivariate logistic regression, and a nomogram was constructed to visualize the risk of NPSLE. The efficacy and accuracy of the model were assessed by receiver operating characteristic (ROC) curve and calibration curve analysis. Net clinical benefit was assessed by decision curve analysis. Variables that were included in the predictive model were anti-dsDNA, anti-SSA, lymphocyte count, hematocrit, erythrocyte sedimentation rate, pre-albumin, retinol binding protein, creatine kinase isoenzyme MB, Nterminal brain natriuretic peptide precursor, creatinine, indirect bilirubin, fibrinogen, hypersensitive C-reactive protein, CO, and mild contamination. The nomogram showed a broad prediction spectrum; the area under the curve (AUC) was 0.895 (0.858-0.931) for the training set and 0.849 (0.783-0.916) for the validation set. The model exhibits good predictive performance and will confer clinical benefit in NPSLE risk calculation. Key Points • Clinical, laboratory, and meteorological data were incorporated into a predictive model for neuropsychiatric systemic lupus erythematosus (NPSLE) in SLE patients. • Anti-dsDNA, anti-SSA, LYM, HCT, ESR, hsCRP, IBIL, PA, RBP, CO, Fib, NT-proBNP, Crea, CO, and mild contamination are predictors of the development of NPSLE and may have potential for research. • The nomogram has good predictive performance and clinical value and can be used to guide clinical diagnosis and treatment.

Efficacy of catheter ablation for atrial fibrillation in heart failure: a meta-analysis of randomized controlled trials.

The study aims to evaluate whether rhythm control by catheter ablation is superior to medical therapy for the patients with atrial fibrillation (AF) and heart failure (HF). The literatures were searched by using PubMed, Cochrane Library, Embase, and Web of Science databases up to 12 October 2023. The randomized controlled trials (RCTs) comparing rhythm control using catheter ablation vs. medical therapy in AF patients with HF were pooled. The primary outcomes included all-cause mortality, HF re-hospitalization, and stroke, and the secondary outcomes included left ventricular ejection fraction (LVEF), atrial tachyarrythmia recurrence, quality of life (Minnesota Living with Heart Failure Questionnaire score, MLHFQ score), 6min walking distance (6MWD), the level of N-terminal B-type natriuretic peptide precursor (NT-proBNP), and adverse events. Nine RCTs involving in 2293 patients met the inclusion criteria. Compared with medical therapy, catheter ablation reduced all-cause mortality [10.07% (121/1201) vs. 15.26% (175/1147), risk ratio (RR):0.60, 95% confidence interval (CI): 0.48-0.74, P<0.00001, I2=0%] and the rate of HF re-hospitalization (RR: 0.65, P=0.02, 95% CI: 0.45 to 0.94, I2=74%), but had no obvious difference in incidence of stroke (RR: 0.67, P=0.27, 95% CI: 0.32 to 1.38, I2=0%). Catheter ablation enhanced LVEF [mean difference (MD), 6.26%, P<0.00001, I2=89%], reduced AT recurrence (RR: 0.37, P<0.00001, 95% CI: 0.26 to 0.52, I2=89%), improved the quality of life (MLHFQ score) (MD: -6.83, P=0.003, I2=67%), elevated 6MWD (MD: 15.92, P=0.006, I2=76%), and diminished the level NT-proBNP (MD: -44.19, P<0.00001, I2=75%), but had no significant difference in adverse events [25.81% (310/1201) vs. 30.25% (347/1147), RR: 0.81, 95% CI: 0.65-1.01, P=0.06, I2=55%]. Catheter ablation as rhythm control strategy substantially enhances the survival rate, reduces HF re-hospitalization, increases the rate of sinus rhythm maintenance, improves the left ventricular function and the quality of life for AF patients with HF, and has similar safety, compared with medical therapy. The rhythm control by catheter ablation may be a better strategy for the AF patients with HF.

Beta-amyloid plaque deposits and increased tau protein in the early diagnosis of alzheimer’s disease: the importance of physical activity in the prevention and evolution of the patient

In recent years, it has become clear that the β-amyloid (Aβ) component of senile plaques may be the key molecule in the pathology of Alzheimer's disease (AD). However, the origin and site of Aβ's neurotoxic action are still the subject of controversy. The precursor of the β-amyloid peptide is the β-amyloid precursor protein, which is predominantly neuronal. The hypothesis is that intraneuronal dysregulation of Amyloid Precursor Protein (APP) leads to the accumulation of Aβ peptides in intracellular compartments. This accumulation impairs the trafficking of APP, which initiates a cascade of pathological changes and causes the degeneration of pyramidal neurons. The increased secretion of Aβ as a function of stressed neurons and degenerated neuron remnants provides seeds for extracellular Aβ aggregates, which induce secondary degenerative events involving neighboring cells such as neurons, astroglia and macrophages/microglia. The benefits of physical exercise to reduce low-grade inflammation and improve cognitive function have become a growing field of interest. Epidemiological research has shown that a sedentary lifestyle intensifies the processes of disability and dependence, and also increases the incidence of chronic diseases. Physical exercise has been inversely associated with high levels of different inflammatory markers. It plays a neurotrophic role, capable of promoting a reduction in the accumulation of β-amyloid peptide and the hyperphosphorylation of tau protein, being an important alternative pathway for reducing the degenerative process, which does not result in the release of pro-inflammatory factors, as well as helping to reduce the levels of pro-inflammatory cytokines and improve peripheral concentrations.

Arterial hypertension in the Arctic: the role of stress and autonomic dysfunction, gender differences

Introduction. Psychological stress and autonomic dysfunction are recognized as risk factors for cardiovascular diseases, but they affect cardiovascular risk differently in men and women.Aim: To study gender differences in factors influencing the probability of detecting arterial hypertension (AH) from the perspective of the role of stress, autonomic dysfunction and nonspecific inflammation in rotational shift workers in the Arctic region.Material and Methods. In the medical unit of the gas production company “Gazprom dobycha Yamburg” (polar settlement of Yamburg, 68°21’40”N) we simultaneously examined 99 men and 81 women with AH 1,2 degree of AH and normotensive persons comparable in age (p = 0.450), work experience in the Arctic (p = 0.956), number of years of rotational shift work (p = 0.824), level of office systolic (SBP) (p = 0.251) and diastolic blood pressure (DBP) (p = 0.579). Questionnaires were used to determine the level of general stress (PSM25 scale), occupational stress (Vaisman questionnaire); assessment of autonomic nervous system (ANS) function (Wayne A.M. questionnaire); 24-hour blood pressure monitoring was performed; biochemical blood test for biomarkers of inflammation, cortisol, brain natriuretic peptide precursor, homocysteine, folliclestimulating hormone was carrued out.Results. Vegetative manifestations (asthenization, increased fatigue, meteorological dependence, headaches) were significantly more often observed in women. Among men with AH, individuals with high levels of neuropsychological tension predominated, every fifth M had a high level of occupational stress. The median scores on the Wayne A.M. questionnaire were significantly higher in women, regardless of BP, and moderate ANS disorders were significantly more prevalent. According to logistic regression data, a significant effect on the probability of AH in men was the number of stress scores (OR = 1.050; 1.029–1.171, p = 0.001), indicators of nocturnal DBP variability (OR = 1.295; 1.109–1.511, p = 0.001) and nonspecific inflammation: rise in high-sensitivity C-reactive protein (hs-CRP) increased the probability of AH by 1.5 times (OR = 1.532; 1.212–1.937, p = 0.001), IL-1β – by 7 times (OR = 7.275; 3.235–16.361, p = 0.001). The probability of AH in women increased by the values of the daily variability of SBP (OR = 1.154; 1.019–1.306, p = 0.024), hs-CRP by 1.5 times (OR = 1.479; 1.226–1.783, p = 0.001), tumor necrosis factor-alpha (TNF-α) (OR = 1.111; 1.001–1.244, p = 0.044), level of IL-6 increased the probability of AH by 1.7 times (OR = 1.676; 1.149–2.958, p = 0.035), the number of scores on ANS questionnaire had a significant effect (OR = 1.055; 1.006–1.107, p = 0.026).Conclusion. In the conditions of the rotational shift work in the Arctic, gender differences were revealed in the stress perception and the severity of ANS dysfunction with a clear relationship between stress, inflammation and AH in men. ANS dysfunction in women was a trigger of nonspecific inflammation and AH. The identified gender differences will help to reveal vulnerable groups among men and women and develop targeted interventions for individuals in the Arctic region.

Visual and quantitative lateral flow immunoassay based on Au@PS SERS tags for multiplex cardiac biomarkers

Rapid and sensitive detection of multiple biomarkers by lateral flow immunoassay (LFIA) remains challenging for signal amplification for commonly used nanotags. Herein, we report a novel LFIA strip for visual and highly sensitive analysis of two cardiac biomarkers based on functionalized gold nanoparticles @ polystyrene microsphere (Au@PS）microcavity as surface-enhanced Raman scattering (SERS) tags. Antibody-modified Au@PS was designed as a SERS label. The evanescent waves propagating along the surface of the PS microcavity and the localized surface plasmons of the gold nanoparticles were coupled to enhance the light-matter interaction synergistically for Raman signal enhancement. In this strategy, the proposed Au@PS SERS tags-based LFIA was carried out to quantify the content of the heart failure and infarct biomarkers synchronously within 15 min and get the limits of detection of 1 pg/mL and 10 pg/mL for cardiac troponin I (cTnI) and N-terminal natriuretic peptide precursor (NT-proBNP), respectively. The results demonstrated 10–20 folds more sensitivity than that of the standard colloidal gold strip and fluorescent strip for the same biomarkers. This novel quantitative LFIA shows promise as a high-sensitive and visual sensing method for relevant clinical and forensic analysis.

Diversity analysis of sea anemone peptide toxins in different tissues of Heteractis crispa based on transcriptomics

Peptide toxins found in sea anemones venom have diverse properties that make them important research subjects in the fields of pharmacology, neuroscience and biotechnology. This study used high-throughput sequencing technology to systematically analyze the venom components of the tentacles, column, and mesenterial filaments of sea anemone Heteractis crispa, revealing the diversity and complexity of sea anemone toxins in different tissues. A total of 1049 transcripts were identified and categorized into 60 families, of which 91.0% were proteins and 9.0% were peptides. Of those 1049 transcripts, 416, 291, and 307 putative proteins and peptide precursors were identified from tentacles, column, and mesenterial filaments respectively, while 428 were identified when the datasets were combined. Of these putative toxin sequences, 42 were detected in all three tissues, including 33 proteins and 9 peptides, with the majority of peptides being ShKT domain, β-defensin, and Kunitz-type. In addition, this study applied bioinformatics approaches to predict the family classification, 3D structures, and functional annotation of these representative peptides, as well as the evolutionary relationships between peptides, laying the foundation for the next step of peptide pharmacological activity research.

Serum Biochemical Markers for Medullary Thyroid Carcinoma: An Update.

Medullary thyroid carcinoma (MTC), a rare malignancy, requires early diagnosis for optimal patient outcomes. An important aspect of MTC diagnosis is the assessment of serum biomarkers. This review aimed to evaluate the use of serum biomarkers in the diagnosis, prognosis, and follow-up of MTC. A thorough search of PubMed covering 1975 to 2022 was conducted to identify English-language articles on MTC serum biomarkers. The review revealed that calcitonin (Ctn) and carcinoembryonic antigen (CEA) remain the most important serum biomarkers for MTC diagnosis and management. Despite limited studies on procalcitonin (PCT), its stability and ability to exclude interference from inflammation make it a valuable potential marker of MTC. Although the positive rate of serum CA19-9 levels in MTC patients was not high, it can be used as an indicator of poor prognosis in advanced MTC. Other serum markers, including chromogranin A, gastrin-releasing peptide precursor, and neurospecific enolase, did not show any unique value in MTC diagnosis and management. Taken together, this review emphasized the importance of serum biomarkers, particularly Ctn and CEA, in the diagnosis and management of MTC. PCT shows promise as a valuable potential marker, whereas CA19-9 can be used as a prognostic indicator of advanced MTC. Further research is needed to validate the significance of these serum biomarkers in MTC and determine the effects of confounding factors on their levels. Clinicians should consider using these markers in MTC diagnosis, prognosis, and follow-up, particularly for patients with advanced disease.

Development and validation of a prognostic model for predicting post-discharge mortality risk in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI)

BackgroundAccurately predicting post-discharge mortality risk in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) remains a complex and critical challenge. The primary objective of this study was to develop and validate a robust risk prediction model to assess the 12-month and 24-month mortality risk in STEMI patients after hospital discharge.MethodsA retrospective study was conducted on 664 STEMI patients who underwent PPCI at Xiangtan Central Hospital Chest Pain Center between 2020 and 2022. The dataset was randomly divided into a training cohort (n = 464) and a validation cohort (n = 200) using a 7:3 ratio. The primary outcome was all-cause mortality following hospital discharge. The least absolute shrinkage and selection operator (LASSO) regression model was employed to identify the optimal predictive variables. Based on these variables, a regression model was constructed to determine the significant predictors of mortality. The performance of the model was evaluated using receiver operating characteristic (ROC) curve analysis and decision curve analysis (DCA).ResultsThe prognostic model was developed based on the LASSO regression results and further validated using the independent validation cohort. LASSO regression identified five important predictors: age, Killip classification, B-type natriuretic peptide precursor (NTpro-BNP), left ventricular ejection fraction (LVEF), and the usage of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/angiotensin receptor-neprilysin inhibitors (ACEI/ARB/ARNI). The Harrell's concordance index (C-index) for the training and validation cohorts were 0.863 (95% CI: 0.792–0.934) and 0.888 (95% CI: 0.821–0.955), respectively. The area under the curve (AUC) for the training cohort at 12 months and 24 months was 0.785 (95% CI: 0.771–0.948) and 0.812 (95% CI: 0.772–0.940), respectively, while the corresponding values for the validation cohort were 0.864 (95% CI: 0.604–0.965) and 0.845 (95% CI: 0.705–0.951). These results confirm the stability and predictive accuracy of our model, demonstrating its reliable discriminative ability for post-discharge all-cause mortality risk. DCA analysis exhibited favorable net benefit of the nomogram.ConclusionThe developed nomogram shows potential as a tool for predicting post-discharge mortality in STEMI patients undergoing PPCI. However, its full utility awaits confirmation through broader external and temporal validation.

Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach.

The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse.

Abstract 2583: [68Ga]Ga-RYZ-GPC3: A glypican-3 targeted diagnostic radiopharmaceutical for hepatocellular carcinoma molecular imaging

Abstract Introduction &amp; Purpose: Hepatocellular carcinoma (HCC) is the most common type of liver cancer. To date, the imaging of HCC is difficult, insufficient for disease staging and barely improved over the past decades. Glypican-3 (GPC3) is a cell-surface receptor highly expressed by HCC and of diagnostic and prognostic value. GPC3 has been reported as potential target for diagnosis and treatment of HCC for nuclear theranostics. RYZ-GPC3 is a DOTA modified macrocyclic peptide with high affinity for GPC3, which may allow PET imaging or nuclear therapy. Here we report the first clinical results of [68Ga]Ga-RYZ-GPC3 PET-imaging in patients with known or suspected HCC. Methods: [68Ga]Ga-RYZ-GPC3 was obtained upon labeling the peptide precursor with 68Ga from a 68Ge/68Ga-generator and heating till 90⁰C for 10 min followed by sterile filtration. After administration of 2 MBq/kg [68Ga]Ga-RYZ-GPC3, a 60 min dynamic PET scan was acquired or multiple static PET/CT were acquired at 20 min, 1, 2 and 4 hours. Besides qualitative interpretation, standardized uptake values (SUVmax, SUVmean) were measured in various compartments; HCC lesions, healthy liver (HL), kidneys, blood pool activity in the left ventricle (BP) and gastric fundus. Additionally, tumor-to-healthy liver ratios (TLR) were calculated: SUVmean,HCC divided by SUVmean,HL. Results: Radiolabeling to obtain [68Ga]Ga-RYZ-GPC3 was near quantitative, making the production highly reliable. Eleven patients (4 patients dynamic; 7 patients static protocol) were scanned. One patient did not have an HCC. Another patient had a concurrent metastatic prostate adenocarcinoma, which did not show uptake, both qualitatively and quantitatively. All HCC lesions showed uptake in qualitative assessment, even in immunohistochemistry confirmed GPC3-negative HCC lesions (3 lesions). In 23 HCC lesions, including the aforementioned GPC3-negative lesions, mean SUVmax was 17.9 (range 2.7-95.3) and mean SUVmean was 10.2 (range 1.0-49.2) at 60 minutes. Uptake in HL and BP decrease over time and become negligible 45 minutes after administration (SUVmean &amp;lt;1.5). The opposite occurs for HCC and TLR, which continuously increase up to 4 hours after administration (TLR 4.4 to 19.2, at 18 minutes and 4 hours respectively). In individual lesion analysis, TLR was the highest at 60 or 120 minutes post-injection scans. Uptake in the gastric fundus, gradually increases in the first hour, and decreases gradually afterwards (SUVmean from 4.0 to 12.7, back to 10.1). Conclusions: [68Ga]Ga-RYZ-GPC3 is the first peptide based PET tracer that allows the high quality molecular imaging of HCC. Thereby [68Ga]Ga-RYZ-GPC3 is suitable for the selective diagnosis of HCC. In addition, based on the biodistribution and in vivo dynamics on these diagnostic images, RYZ-GPC3 is very likely to hold therapeutic potential upon labeling with a therapeutic isotope (e.g 177Lu or 225Ac). Citation Format: Arthur J.A.T. Braat, Alex J. Poot, Constantin Lapa, Marnix G.E.H. Lam, Wolfgang A. Weber, Anna Karmann, Ye Yuan, Jessica Rearden, Ken Song, Ralph A. Bundschuh. [68Ga]Ga-RYZ-GPC3: A glypican-3 targeted diagnostic radiopharmaceutical for hepatocellular carcinoma molecular imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2583.

Molecular Cloning and Functional Analysis of Secretory Phospholipase A2 from Apostichopus japonicus.

Secretory phospholipase A2 (sPLA2) plays important roles in phospholipid metabolism, skin barrier maintenance, immune response and other processes in organisms. sPLA2 of sea cucumber A. japonicus (AjPLA2) has not yet been reported. This study successfully amplified the AjPLA2 sequence. The total cDNA of AjPLA2 is 931bp, including a 480bp ORF that encodes 159 amino acids. The AjPLA2 protein includes a 16-aa signal peptide, a 5-aa precursor peptide and a 138-aa mature peptide. Homologous alignment showed that AjPLA2 and the sPLA2s from starfish have the typical domains of the Group IB sPLA2. And additional amino acid sequences were found around the β-Wing, which is different from the Group IB sPLA2. These results showed that AjPLA2 and sPLA2s from starfish all belong to a new group in the Group I sPLA2 family. AjPLA2 is widely distributed in sea cucumber tissues. The functional analysis also showed that AjPLA2 was upregulated in the intestine by feeding. Whenthe body wall was damaged, it was significantly upregulated around the wound. And the expression levels of AjPLA2 were significantly increased in V. splendens-infected sea cucumbers. The results indicated that AjPLA2 plays roles in the sea cucumber immunologicprocess. Combined with the upregulation of unsaturated fatty acids (PUFAs) content in A. japonicus, it demonstrated that AjPLA2 could participate in the immune of A. japonicus by hydrolyzing phospholipid and releasing PUFAs. This study had a solid foundation for the further research of AjPLA2 gene function in vivo, development and application of AjPLA2 protein.

Tryptophan-Centric Bioinformatics Identifies New Lasso Peptide Modifications.

Lasso peptides are a class of ribosomally synthesized and post-translationally modified peptides (RiPPs) defined by a macrolactam linkage between the N-terminus and the side chain of an internal aspartic acid or glutamic acid residue. Instead of adopting a branched-cyclic conformation, lasso peptides are "threaded", with the C-terminal tail passing through the macrocycle to present a kinetically trapped rotaxane conformation. The availability of enhanced bioinformatics methods has led to a significant increase in the number of secondary modifications found on lasso peptides. To uncover new ancillary modifications in a targeted manner, a bioinformatic strategy was developed to discover lasso peptides with modifications to tryptophan. This effort identified numerous putative lasso peptide biosynthetic gene clusters with core regions of the precursor peptides enriched in tryptophan. Parsing of these tryptophan (Trp)-rich biosynthetic gene clusters uncovered several putative ancillary modifying enzymes, including halogenases and dimethylallyltransferases expected to act upon Trp. Characterization of two gene products yielded a lasso peptide with two 5-Cl-Trp modifications (chlorolassin) and another bearing 5-dimethylallyl-Trp and 2,3-didehydro-Tyr modifications (wygwalassin). Bioinformatic analysis of the requisite halogenase and dimethylallyltransferase revealed numerous other putative Trp-modified lasso peptides that remain uncharacterized. We anticipate that the Trp-centric strategy reported herein may be useful in discovering ancillary modifications for other RiPP classes and, more generally, guide the functional prediction of enzymes that act on specific amino acids.

Synthesis and Functionalization of Azetidine-Containing Small Macrocyclic Peptides.

Cyclic peptides are increasingly important structures in drugs but their development can be impeded by difficulties associated with their synthesis. Here, we introduce the 3-aminoazetidine (3-AAz) subunit as a new turn-inducing element for the efficient synthesis of small head-to-tail cyclic peptides. Greatly improved cyclizations of tetra-, penta- and hexapeptides (28 examples) under standard reaction conditions are achieved by introduction of this element within the linear peptide precursor. Post-cyclization deprotection of the amino acid side chains with strong acid is realized without degradation of the strained four-membered azetidine. An special feature of this chemistry is that further late-stage modification of the resultant macrocyclic peptides can be achieved via the 3-AAz unit.This is done by: (i) chemoselective deprotection and substitution at the azetidine nitrogen, or by (ii) a click-based approach employing a 2-propynyl carbamate on the azetidine nitrogen. In this way, a range of dye and biotin tagged macrocycles are readily produced. Structural insights gained by XRD analysis of a cyclic tetrapeptide indicate that the azetidine ring encourages access to the less stable, all-trans conformation. Moreover, introduction of a 3-AAz into a representative cyclohexapeptide improves stability towards proteases compared to the homodetic macrocycle.