A coherent FOXO3-SNAI2 feed-forward loop in autophagy.

SignificanceUnderstanding autophagy regulation is instrumental in developing therapeutic interventions for autophagy-associated disease. Here, we identified SNAI2 as a regulator of autophagy from a genome-wide screen in HeLa cells. Upon energy stress, SNAI2 is transcriptionally activated by FOXO3 and interacts with FOXO3 to form a feed-forward regulatory loop to reinforce the expression of autophagy genes. Of note, SNAI2-increased FOXO3-DNA binding abrogates CRM1-dependent FOXO3 nuclear export, illuminating a pivotal role of DNA in the nuclear retention of nucleocytoplasmic shuttling proteins. Moreover, a dFoxO-Snail feed-forward loop regulates both autophagy and cell size in Drosophila, suggesting this evolutionarily conserved regulatory loop is engaged in more physiological activities.

Antiviral activity of luteolin against porcine epidemic diarrhea virus in silico and in vitro.

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) mainly causes acute and severe porcine epidemic diarrhea (PED), and is highly fatal in neonatal piglets. No reliable therapeutics against the infection exist, which poses a major global health issue for piglets. Luteolin is a flavonoid with anti-viral activity toward several viruses. RESULTS: We evaluated anti-viral effects of luteolin in PEDV-infected Vero and IPEC-J2 cells, and identified IC50 values of 23.87 µM and 68.5 µM, respectively. And found PEDV internalization, replication and release were significantly reduced upon luteolin treatment. As luteolin could bind to human ACE2 and SARS-CoV-2 main protease (Mpro) to contribute viral entry, we first identified that luteolin shares the same core binding site on pACE2 with PEDV-S by molecular docking and exhibited positive pACE2 binding with an affinity constant of 71.6 µM at dose-dependent increases by surface plasmon resonance (SPR) assay. However, pACE2 was incapable of binding to PEDV-S1. Therefore, luteolin inhibited PEDV internalization independent of PEDV-S binding to pACE2. Moreover, luteolin was firmly embedded in the groove of active pocket of Mpro in a three-dimensional docking model, and fluorescence resonance energy transfer (FRET) assays confirmed that luteolin inhibited PEDV Mpro activity. In addition, we also observed PEDV-induced pro-inflammatory cytokine inhibition and Nrf2-induced HO-1 expression. Finally, a drug resistant mutant was isolated after 10 cell culture passages concomitant with increasing luteolin concentrations, with reduced PEDV susceptibility to luteolin identified at passage 10. CONCLUSIONS: Our results push forward that anti-PEDV mechanisms and resistant-PEDV properties for luteolin, which may be used to combat PED.

Mechanistic insights and implications of FOXO-SNAI interplay.

Autophagy promotes both health and disease, depending on tissue types and genetic contexts, yet the regulatory mechanism remain incompletely understood. Our recent publication has uncovered a coherent FOXO-SNAI feed-forward loop in autophagy, which is evolutionarily conserved from Drosophila to human. In addition, it's revealed that DNA binding plays a critical role in intracellular localization of nucleocytoplasmic shuttling proteins. Based on these findings, herein we further integrate mechanistic insights of FOXO-SNAI regulatory interplay in autophagy and unravel the potential link of FOXO-induced autophagy with SNAI in diseases. Besides, the generality of DNA-retention mechanism on transcription factor nuclear localization is illustrated with wide-ranging discussion, and more functions potentially regulated by FOXO-SNAI feedforward loop are provided. Elucidation of these unsolved paradigms will expand the understanding of FOXO-SNAI interplay and facilitate the development of new therapeutics targeting FOXO-SNAI axis in diseases.

Robust Offloading for Edge Computing-Assisted Sensing and Communication Systems: A Deep Reinforcement Learning Approach.

In this paper, we consider an integrated sensing, communication, and computation (ISCC) system to alleviate the spectrum congestion and computation burden problem. Specifically, while serving communication users, a base station (BS) actively engages in sensing targets and collaborates seamlessly with the edge server to concurrently process the acquired sensing data for efficient target recognition. A significant challenge in edge computing systems arises from the inherent uncertainty in computations, mainly stemming from the unpredictable complexity of tasks. With this consideration, we address the computation uncertainty by formulating a robust communication and computing resource allocation problem in ISCC systems. The primary goal of the system is to minimize total energy consumption while adhering to perception and delay constraints. This is achieved through the optimization of transmit beamforming, offloading ratio, and computing resource allocation, effectively managing the trade-offs between local execution and edge computing. To overcome this challenge, we employ a Markov decision process (MDP) in conjunction with the proximal policy optimization (PPO) algorithm, establishing an adaptive learning strategy. The proposed algorithm stands out for its rapid training speed, ensuring compliance with latency requirements for perception and computation in applications. Simulation results highlight its robustness and effectiveness within ISCC systems compared to baseline approaches.

Joint Effects Between CDKN2B/P15 Methylation and Environmental Factors on the Susceptibility to Gastric Cancer.

BACKGROUND: The incidence of gastric cancer has long been at a high level in China, seriously affecting the health of Chinese people. AIMS: This case‒control study was performed to identify gene methylation biomarkers of gastric cancer susceptibility. METHODS: A total of 393 gastric cancer cases and 397 controls were included in this study. Gene methylation in peripheral blood leukocytes was detected by a methylation-sensitive high-resolution melting method, and the Helicobacter pylori antibody presence was semi-quantified in serum by ELISA. RESULTS: Individuals with total methylation of CDKN2B/P15 had a 1.883-fold (95%CI: 1.166-3.040, P = 0.010) risk of gastric cancer compared with unmethylated individuals. Individuals with both CDKN2B/P15 and NEUROG1 methylation had a higher risk of gastric cancer (OR = 2.147, 95% CI: 1.137-4.073, P = 0.019). The interaction between CDKN2B/P15 and NEUROG1 total methylation on gastric cancer risk was affected by the pattern of adjustment. In addition, the joint effects between CDKN2B/P15 total methylation and environmental factors, such as freshwater fish intake (OR = 6.403, 95% CI = 2.970-13.802, P < 0.001), irregular diet (OR = 5.186, 95% CI = 2.559-10.510, P < 0.001), unsanitary water intake (OR = 2.238, 95% CI = 1.144-4.378, P = 0.019), smoking (OR = 2.421, 95% CI = 1.456-4.026, P = 0.001), alcohol consumption(OR = 2.163, 95% CI = 1.309-3.576, P = 0.003), and garlic intake(OR = 0.373, 95% CI = 0.196-0.709, P = 0.003) on GC risk were observed, respectively. However, CDKN2B/P15 and NEUROG1 total methylation were not associated with gastric cancer prognosis. CONCLUSION: CDKN2B/P15 methylation in peripheral blood may be a potential biomarker for evaluating susceptibility to gastric cancer. The joint effects between CDKN2B/P15 methylation and environmental factors may also contribute to gastric cancer susceptibility.

Risk factors associated with cardiovascular mortality among gastric cancer patients: a population-based analysis.

BACKGROUND: Cancer patients were found at a high risk of death from cardiovascular disease. This study aims to assess cardiovascular mortality risk and identify the potential risk factors associated with cardiovascular mortality among gastric cancer patients. METHODS: Gastric cancer patients were collected from the Surveillance Epidemiology and End Results database during 1975-2016. Standardized mortality ratios were calculated to compare cardiovascular mortality rates between gastric cancer patients and the general US population. Univariable Cox analysis and multivariable stepwise Cox analysis were adopted to identify the potential risk factors for cardiovascular disease death after gastric cancer diagnosis. RESULTS: There were 10 886 cardiovascular disease deaths identified among 165 433 individuals with gastric cancer observed for 410207.20 person-years. Gastric cancer patients were at a higher cardiovascular disease mortality risk (standardized mortality ratio = 3.35, 95% confidence interval: 3.24-3.47, P < 0.05). The study showed that older age at diagnosis (>80 years vs. 0-69 years, hazard ratio = 7.05, 95% confidence interval: 6.66-7.46, P < 0.001; 70-80 years vs. 0-69 years, hazard ratio = 3.35, 95% confidence interval: 3.19-3.53, P < 0.001), male sex (vs. female, hazard ratio = 1.39, 95% confidence interval: 1.33-1.45, P < 0.001), black race (vs. white, hazard ratio = 1.31, 95% confidence interval: 1.24-1.38, P < 0.001), without a partner (divorced/separated vs. married/partnered, hazard ratio = 1.35, 95% confidence interval: 1.25-1.45, P < 0.001; single vs. married/partnered, hazard ratio = 1.20, 95% confidence interval: 1.12-1.29, P < 0.001; widowed vs. married/partnered, hazard ratio = 1.41, 95% confidence interval: 1.34-1.48, P < 0.001), living in the northern plains (vs. pacific coast, hazard ratio = 1.23, 95% confidence interval: 1.16-1.29, P < 0.001) and surgery not performed (vs. performed, hazard ratio = 1.70, 95% confidence interval: 1.61-1.79, P < 0.001) were significantly associated with increased risk of cardiovascular disease death. Compared with patients with localized stage, distant staged patients were less likely to die of cardiovascular disease (hazard ratio = 0.88, 95% confidence interval: 0.83-0.94, P < 0.001). CONCLUSIONS: Gastric cancer patients were at an increased risk of cardiovascular disease death. Older age at diagnosis, male sex, black race, without a partner, living in the northern plains and surgery not performed were significantly associated with cardiovascular disease death after gastric cancer diagnosis.

The plant circadian clock regulates autophagy rhythm through transcription factor LUX ARRHYTHMO.

Autophagy is an evolutionarily conserved degradation pathway in eukaryotes; it plays a critical role in nutritional stress tolerance. The circadian clock is an endogenous timekeeping system that generates biological rhythms to adapt to daily changes in the environment. Accumulating evidence indicates that the circadian clock and autophagy are intimately interwoven in animals. However, the role of the circadian clock in regulating autophagy has been poorly elucidated in plants. Here, we show that autophagy exhibits a robust circadian rhythm in both light/dark cycle (LD) and in constant light (LL) in Arabidopsis. However, autophagy rhythm showed a different pattern with a phase-advance shift and a lower amplitude in LL compared to LD. Moreover, mutation of the transcription factor LUX ARRHYTHMO (LUX) removed autophagy rhythm in LL and led to an enhanced amplitude in LD. LUX represses expression of the core autophagy genes ATG2, ATG8a, and ATG11 by directly binding to their promoters. Phenotypic analysis revealed that LUX is responsible for improved resistance of plants to carbon starvation, which is dependent on moderate autophagy activity. Comprehensive transcriptomic analysis revealed that the autophagy rhythm is ubiquitous in plants. Taken together, our findings demonstrate that the LUX-mediated circadian clock regulates plant autophagy rhythms.

Correlation Between Vasoactive-Inotropic Score and Postoperative Acute Kidney Injury after Cardiovascular Surgery.

BACKGROUND: Acute kidney injury (AKI) is a common complication of cardiovascular surgery. The aim of this study was to investigate the correlation between Vasoactive-Inotropic Score (VIS) and postoperative acute kidney injury in adult patients with cardiovascular surgery. METHODS: We retrospectively reviewed the data of 1935 adult patients who underwent cardiovascular surgery between September 2017 and May 2019. The data of patients included demographic data, laboratory findings, intraoperative details, and postoperative clinical outcomes. We calculated VIS-max by using the highest doses of vasoactive and inotropic medications during the first 24h after cardiovascular surgery. Logistic regression model was used to evaluate whether the VIS-max was independently associated with postoperative AKI. Additionally, improvements in risk reclassification and discrimination were evaluated by calculating the net reclassification improvement (NRI), C-index and the integrated discrimination improvement (IDI) with the addition of the VIS-max to a baseline model of the Society of Thoracic Surgeons (STS) score for analyzing the association of VIS-max with postoperative AKI. RESULTS: In 1935 patients, 291 patients (15.0%) developed postoperative AKI from the second to seventh day after cardiovascular surgery, and 30 patients (1.6%) needed renal replacement therapy (RRT). In 291 patients with AKI, 3 patients (0.2%) with AKI class 1, 12 patients (0.6%) with AKI class 2, and 15 patients (0.8%) with AKI class 3 needed RRT. Multivariate logistic regression analysis showed that VIS-max was associated with postoperative AKI (odds ratio [OR]: 1.19, 95% confidence interval [CI]: 1.11-1.34, P < 0.001) and the need for RRT in AKI patients (OR: 1.29, 95%CI: 1.01-1.83, P = 0.007). The area under the ROC curves (AUROC) of VIS-max combining STS score for predicting postoperative AKI (AUROC: 0.84, 95%CI: 0.81-0.87, P < 0.001) and need of RRT (AUROC: 0.91, 95%CI: 0.86-0.96, P < 0.001) significantly were higher than the AUC of VIS-max, STS score and EuroSCORE. Inclusion of VIS-max into basic risk model of STS score provided an increase in all indexes of prognostic accuracy for postoperative AKI and need of RRT: C-statistic: 0.721, NRI: 21.8%, IDI: 4.9%; and C-statistic: 0.745, NRI: 24.7%, IDI: 5.6%, respectively. CONCLUSION: VIS-max is an independent predictor of postoperative AKI in adult patients after cardiovascular surgery and increases prognostic accuracy of STS score, allowing a risk reclassification.

miR-155 increases stemness and decitabine resistance in triple-negative breast cancer cells by inhibiting TSPAN5.

Effective therapeutic targets for triple-negative breast cancer (TNBC), a special type of breast cancer (BC) with rapid metastasis and poor prognosis, are lacking, especially for patients with chemotherapy resistance. Decitabine (DCA) is a Food and Drug Administration-approved DNA methyltransferase inhibitor that has been proven effective for the treatment of tumors. However, its antitumor effect in cancer cells is limited by multidrug resistance. Cancer stem cells (CSCs), which are thought to act as seeds during tumor formation, regulate tumorigenesis, metastasis, and drug resistance through complex signaling. Our previous study found that miR-155 is upregulated in BC, but whether and how miR-155 regulates DCA resistance is unclear. In this study, we demonstrated that miR-155 was upregulated in CD24- CD44+ BC stem cells (BCSCs). In addition, the overexpression of miR-155 increased the number of CD24- CD44+ CSCs, DCA resistance and tumor clone formation in MDA-231 and BT-549 BC cells, and knockdown of miR-155 inhibited DCA resistance and stemness in BCSCs in vitro. Moreover, miR-155 induced stemness and DCA resistance by inhibiting the direct target gene tetraspanin-5 (TSPAN5). We further confirmed that overexpression of TSPAN5 abrogated the effect of miR-155 in promoting stemness and DCA resistance in BC cells. Our data show that miR-155 increases stemness and DCA resistance in BC cells by targeting TSPAN5. These data provide a therapeutic strategy and mechanistic basis for future possible clinical applications targeting the miR-155/TSPAN5 signaling axis in the treatment of TNBC.

Differential nitric oxide induced by Mycobacterium bovis and BCG leading to dendritic cells apoptosis in a caspase dependent manner.

Dendritic cells (DCs) are critical for both innate and adaptive immunity. Meanwhile, nitric oxide (NO) is a member of reactive nitrogen species (RNS) generally considered to play a key role in the bactericidal process in innate immunity against Mycobacterium tuberculosis complex infection. The present study therefore investigated the mechanism of NO production in murine DCs induced by Mycobacterium bovis (M.bovis) and its attenuated strain Bacillus Calmette-Guérin (BCG) infection. The expression of genes Slc7A1, Slc7A2, iNOS, and ArgI essential to NO synthesis was up-regulated in M.bovis/BCG infected DCs. IFN-γ addition further increased, while the iNOS inhibitor L-NMMA significantly inhibited their expression. Accordingly, the end products of arginine metabolism, NO and urea, were found to be significantly increased. In addition, BCG induced significantly higher levels of apoptosis in DCs compared to M.bovis shown by higher levels of DNA fragmentation using flow cytometry and release of mitochondrial Cytochrome C, and up-regulation of the genes caspase-3, caspase-8, caspase-9 and dffa critical to apoptosis by qRT-PCR detection and western blot analysis. Furthermore, IFN-γ increased, but L-NMMA decreased apoptosis of M.bovis/BCG infected DCs. In addition, mycobacterial intracellular survival was significantly reduced by IFN-γ treatment in BCG infected DCs, while slightly increased by L-NMMA treatment. Taken altogether, our data show that NO synthesis was differentially increased and associated with apoptosis in M.bovis/BCG infected DCs. These findings may significantly contribute to elucidate the pathogenesis of M.bovis.

TRIM25 upregulation by Mycobacterium tuberculosis infection promotes intracellular survival of M.tb in RAW264.7 cells.

Tripartite motif 25 (TRIM25) is a TRIM family member which is involved in innate immunity. However, its role in the modulation of host defense against Mycobacterium tuberculosis (M.tb) infection has not been investigated. Therefore, this study aimed to demonstrate the significance of TRIM25 in the regulation of macrophage responses to M.tb infection. TRIM25 was found to be significantly overexpressed (3.476-fold) in peripheral blood mononuclear cells (PBMCs) of 67 patients with pulmonary tuberculosis compared with 48 healthy controls. TRIM25 expression was enhanced following M.tb infection of RAW264.7 cells, a macrophage cell line. Overexpression of TRIM25 in M.tb-infected RAW264.7 cells led to a significant increase in phosphorylated p38 levels; however, the production of IL-6, IL-1ß, and TNF-α were significantly reduced. Finally, M.tb intracellular survival increased by 90% at 12 h post-infection (PI) (p < 0.01). To validate the previous results, TRIM25 levels in M.tb-infected RAW264.7 macrophages were down-regulated using small interfering RNA (siRNA). Therefore, it was concluded that TRIM25 promotes intracellular survival of M.tb in RAW264.7 cells, likely by enhancing p38 pathways and thereby inhibiting the production of proinflammatory cytokines. These results contribute to the further understanding of the host defense against M.tb infection.

Dynamic Responses of a Metro Train-Bridge System under Train-Braking: Field Measurements and Data Analysis.

This paper focuses on the dynamic responses of a metro train-bridge system under train-braking. Experiments were performed on the elevated Metro Line 21 of Guangzhou (China). A continuous, three-span, rigid-frame bridge (42 m + 65 m + 42 m) and a standard B-type metro train were selected. The acceleration signals were measured at the center-points of the main span and one side-span, and the acceleration signals of the car body and the bogie frame were measured simultaneously. The train-bridge system's vibration characteristics and any correlations with time and frequency were investigated. The Choi-Williams distribution method and wavelet coherence were introduced to analyze the obtained acceleration signals of the metro train-bridge system. The results showed that the Choi-Williams distribution provided a more explicit understanding of the time-frequency domain. The correlations between different parts of the bridge and the train-bridge system under braking conditions were revealed. The present study provides a series of measured dynamic responses of the metro train-bridge system under train-braking, which could be used as a reference in further investigations.

K+ Efflux Antiporters 4, 5, and 6 Mediate pH and K+ Homeostasis in Endomembrane Compartments.

KEA4, KEA5, and KEA6 are members of the Arabidopsis (Arabidopsis thaliana) K+ efflux antiporter (KEA) family that share high sequence similarity but whose function remains unknown. Here, we show their gene expression pattern, subcellular localization, and physiological function in Arabidopsis. KEA4, KEA5, and KEA6 had similar tissue expression patterns, and the three KEA proteins localized to the Golgi, the trans-Golgi network, and the prevacuolar compartment/multivesicular bodies, suggesting overlapping roles of these proteins in the endomembrane system. Phenotypic analyses of single, double, and triple mutants confirmed functional redundancy. The triple mutant kea4 kea5 kea6 had small rosettes, short seedlings, and was sensitive to low K+ availability and to the sodicity imposed by high salinity. Also, the kea4 kea5 kea6 mutant plants had a reduced luminal pH in the Golgi, trans-Golgi network, prevacuolar compartment, and vacuole, in accordance with the K/H exchange activity of KEA proteins. Genetic analysis indicated that KEA4, KEA5, and KEA6 as well as endosomal Na+/H+exchanger5 (NHX5) and NHX6 acted coordinately to facilitate endosomal pH homeostasis and salt tolerance. Neither cancelling nor overexpressing the vacuolar antiporters NHX1 and NHX2 in the kea4 kea5 kea6 mutant background altered the salt-sensitive phenotype. The NHX1 and NHX2 proteins in the kea4 kea5 kea6 mutant background could not suppress the acidity of the endomembrane system but brought the vacuolar pH close to wild-type values. Together, these data signify that KEA4, KEA5, and KEA6 are endosomal K+ transporters functioning in maintaining pH and ion homeostasis in the endomembrane network.

Inhalable dry powder prepared from folic acid-conjugated docetaxel liposomes alters pharmacodynamic and pharmacokinetic properties relevant to lung cancer chemotherapy.

Pulmonary delivery of anti-cancer drugs in the form of nanoparticulate dry powders is considered a promising modality for treating lung cancer. However, it is not known whether the pharmacodynamics and pharmacokinetics of nano-preparations are altered after co-spray drying. In this study, we compared the physicochemical property, anti-cancer activity, tumor targeting and pharmacokinetic behavior of docetaxel-loaded folic acid-conjugated liposomes (LPs-DTX-FA) with those of dry powder prepared by co-spray-drying LPs-DTX-FA. The particle size and PDI after re-dispersion of the powder were increased. The re-dispersed liposomes showed increased cellular uptake via micropinocytosis and exhibited higher cytotoxicity than LPs-DTX-FA. Tumor targeting of re-dispersed liposomes was less effective compared with LPs-DTX-FA but the metabolism of re-dispersed liposomes was decreased. Tracheal administration resulted in a 45-fold higher concentration of docetaxel in the lung of Sprague Dawley rats at 30 min as compared with intravenous administration. Our results indicated that co-spray drying did change the properties, while tracheal administration of the dry powder provided higher drug exposure at the tumor site without increasing the exposure of other organs. Thus, inhaled dry powders might be clinically effective for treatment of lung cancer.

MALAT1 promotes the colorectal cancer malignancy by increasing DCP1A expression and miR203 downregulation.

The long non-coding RNA MALAT1 has been proved to promote the cell proliferation, drug resistance, invasion, and metastasis of colorectal cancer (CRC) in vitro and in vivo by regulating the expression of various oncogenes and their protein products. Our previous work discovered that the expression of the mRNA-decapping enzymes 1a (DCP1A) is upregulated in CRCs. However, the relationships between MALAT1 and DCP1A in the development of CRC and the underlying mechanisms are still unclear. In this study, we investigated the molecular mechanisms by which MALAT1 and DCP1A may be linked to contribute to the malignancies of CRCs. We found that DCP1A is a direct target molecule of MALAT1. Moreover, by screening the downstream genes of MALAT1, we noticed that microRNA 203(miR203), an oncogene suppressor in numerous cancers, is inversely correlated to both MALAT1 and DCP1A expressions. Following MALAT1 knockdown, we observed overexpression of miR203 accompanied with DCP1A downregulation to a level that reversed the promoted cell proliferation, invasion, and migration in vitro and in vivo, which could be restored by miR203 knockdown or DCP1A overexpression. These results proposed a new molecular mechanism of MALAT-miR203-DCP1A axis which is involved with the development and contributes to the malignancy of colorectal cancers.

The influence of the carotid baroreflex on dynamic regulation of cerebral blood flow and cerebral tissue oxygenation in humans at rest and during exercise.

PURPOSE: This preliminary study tested the hypothesis that the carotid baroreflex (CBR) mediated sympathoexcitation regulates cerebral blood flow (CBF) at rest and during dynamic exercise. METHODS: In seven healthy subjects (26 ± 1 years), oscillatory neck pressure (NP) stimuli of + 40 mmHg were applied to the carotid baroreceptors at a pre-determined frequency of 0.1 Hz at rest, low (10 ± 1W), and heavy (30 ± 3W) exercise workloads (WLs) without (control) and with α - 1 adrenoreceptor blockade (prazosin). Spectral power analysis of the mean arterial blood pressure (MAP), mean middle cerebral artery blood velocity (MCAV), and cerebral tissue oxygenation index (ScO2) in the low-frequency range (0.07-0.20 Hz) was estimated to examine NP stimuli responses. RESULTS: From rest to heavy exercise, WLs resulted in a greater than three-fold increase in MCAV power (42 ± 23.8-145.2 ± 78, p < 0.01) and an almost three-fold increase in ScO2 power (0.51 ± 0.3-1.53 ± 0.8, p = 0.01), even though there were no changes in MAP power (from 24.5 ± 21 to 22.9 ± 11.9) with NP stimuli. With prazosin, the overall MAP (p = 0.0017), MCAV (p = 0.019), and ScO2 (p = 0.049) power was blunted regardless of the exercise conditions. Prazosin blockade resulted in increases in the Tf gain index between MAP and MCAV compared to the control (p = 0.03). CONCLUSION: CBR-mediated changes in sympathetic activity contribute to dynamic regulation of the cerebral vasculature and CBF at rest and during dynamic exercise in humans.

Novel Natural Angiotensin Converting Enzyme (ACE)-Inhibitory Peptides Derived from Sea Cucumber-Modified Hydrolysates by Adding Exogenous Proline and a Study of Their Structure⁻Activity Relationship.

Natural angiotensin converting enzyme (ACE)-inhibitory peptides, which are derived from marine products, are useful as antihypertensive drugs. Nevertheless, the activities of these natural peptides are relatively low, which limits their applications. The aim of this study was to prepare efficient ACE-inhibitory peptides from sea cucumber-modified hydrolysates by adding exogenous proline according to a facile plastein reaction. When 40% proline (w/w, proline/free amino groups) was added, the modified hydrolysates exhibited higher ACE-inhibitory activity than the original hydrolysates. Among the modified hydrolysates, two novel efficient ACE-inhibitory peptides, which are namely PNVA and PNLG, were purified and identified by a sequential approach combining a sephadex G-15 gel column, reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS), before we conducted confirmatory studies with synthetic peptides. The ACE-inhibitory activity assay showed that PNVA and PNLG exhibited lower IC50 values of 8.18 ± 0.24 and 13.16 ± 0.39 µM than their corresponding truncated analogs (NVA and NLG), respectively. Molecular docking showed that PNVA and PNLG formed a larger number of hydrogen bonds with ACE than NVA and NLG, while the proline at the N-terminal of peptides can affect the orientation of the binding site of ACE. The method developed in this study may potentially be applied to prepare efficient ACE-inhibitory peptides, which may play a key role in hypertension management.

Nonneutralizing Antibodies Induced by the HIV-1 gp41 NHR Domain Gain Neutralizing Activity in the Presence of the HIV Fusion Inhibitor Enfuvirtide: a Potential Therapeutic Vaccine Strategy.

A key barrier against developing preventive and therapeutic human immunodeficiency virus (HIV) vaccines is the inability of viral envelope glycoproteins to elicit broad and potent neutralizing antibodies. However, in the presence of fusion inhibitor enfuvirtide, we show that the nonneutralizing antibodies induced by the HIV type 1 (HIV-1) gp41 N-terminal heptad repeat (NHR) domain (N63) exhibit potent and broad neutralizing activity against laboratory-adapted HIV-1 strains, including the drug-resistant variants, and primary HIV-1 isolates with different subtypes, suggesting the potential of developing gp41-targeted HIV therapeutic vaccines.

Investigation on pharmacokinetics, tissue distribution and excretion of 1-triacontanol in rats by gas chromatography-tandem mass spectrometry (GC-MS/MS).

1. 1-Triacontanol (TA) recently shows promising anti-tumor activity. The present study was aimed to develop a sensitive gas chromatography-tandem mass spectrometry method to explore the pharmacokinetic profiles, distribution and excretion of TA in Sprague-Dawley rats after oral administration of TA. Chromatography separation was performed on a HP-5MS column. 1-Octacosanal was used as the internal standard (IS). Quantification of TA and IS was carried out at m/z 495.6 → 97.0 and m/z 467.5 → 97.0, respectively, in positive electron ionization and multiple reaction monitoring mode. The pharmacokinetic parameters were calculated by non-compartmental analysis. 2. The area under concentration-time curve AUC0-6 h and AUC0-∞ for TA at 60 mg/kg were 87.737 ± 13.574 and 93.617 ± 17.62, respectively. The mean residence time was 3.25 ± 0.17 h. In addition, the elimination half-lives (t1/2) were (2.37 ± 1.23, 1.27 ± 0.49, 2.07 ± 0.93) h after single oral administration of 30, 60 and 120 mg/kg of TA. After oral administration, TA was extensively distributed in stomach and intestine. The majority of TA excreted via feces, and its accumulative excretion ratio during the period of 72 h was 26.68 ± 7.14%, but only 0.0023 ± 0.0015% and 0.0027 ± 0.0006% for urines and bile, respectively. The absolute bioavailability (F, %) of TA was about 2.0%.

Trace quantification of 1-triacontanol in beagle plasma by GC-MS/MS and its application to a pharmacokinetic study.

1-Triacontanol (TA), a member of long chain fatty alcohol, has recently been received great attention owing to its antitumor activity. In this study, an accurate, sensitive and selective gas chromatography-tandem mass spectrometry method was developed and validated for the quantification of TA in beagle plasma using 1-octacosanal as the internal standard (IS) for the first time. With temperature programming, chromatographic separation was carried out on an HP-5MS column, using helium as carrier gas and argon as collision gas, both at a flow rate of 1 mL/min. TA was analyzed using positive ion electrospray ionization in multiple-reaction monitoring mode, with the precursor to product ion transitions of m/z 495.6 → 97.0 and m/z 467.5 → 97.0 for TA and the IS, respectively. The lower limit of quantitation, linearity, intra- and interday precision, accuracy, stability, extraction recovery and matrix effect of TA were within the acceptable limits. The validated method was successfully applied to a pharmacokinetic study of TA in beagles.