Afterglow Electrochemiluminescence from Nitrogen-Deficient Graphitic Carbon Nitride.

Almost all current electrochemiluminescent reagents require real-time electrochemical stimulation to emit light. Here, we report a novel electrochemiluminescent reagent, nitrogen-deficient graphitic carbon nitride (CNx), that can emit afterglow electrochemiluminescence (ECL) after cessation of electric excitation. CNx obtained by post-thermal treatment of graphitic carbon nitride (CN) with KSCN has a cyanamide group and a nitrogen vacancy, which created defects to trap electrically injected electrons. The trapped electrons can slowly release and react with coreactants to emit light with longevity. The cathodic afterglow ECL lasts for 70 s after pulsing the CNx nanosheet (CNxNS-1.6)-modified glassy carbon electrode at -1.0 V for 20 s in 2.0 M PBS containing 1 mM K2S2O8. The afterglow ECL mechanism is revealed by investigation of its influencing factors and ECL wavelength. The discovery of afterglow ECL may open a new doorway for new significant applications of the ECL technique and provide a deeper understanding of the structure-property relationships of CN.

The Differences of Nutrient Components in Edible and Feeding Coix Seed at Different Developmental Stages Based on a Combined Analysis of Metabolomics.

Coix lachryma-jobi L. is an excellent plant resource that has a concomitant function for medicine, foodstuff and forage in China. At present, the commonly used cultivar for both medicine and foodstuff is Xiaobaike, and the cultivar for foraging is Daheishan. However, differences in the internal composition of plants lead to the expression of different phenotypic traits. In order to comprehensively elucidate the differences in nutrient composition changes in Coix seeds, a non-targeted metabolomics method based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) was used to analyze the metabolic changes in Coix seeds at different developmental stages. An edible Coix relative (Xiaobaike) and a feeding Coix relative (Daheishan) were selected as the research subjects. In the metabolome analysis of Coix seed, 314 metabolites were identified and detected, among which organic acids, carbohydrates, lipids, nucleotides and flavonoids were the main components. As an important standard for evaluating the quality of Coix seed, seven lipids were detected, among which fatty acids included not only even-chain fatty acids, but also odd-chain fatty acids, which was the first time detecting a variety of odd-chain fatty acids in Coix seed. The analysis of the compound contents in edible and feeding-type Coix lachryma-jobi L. and the lipid content at the mature stage showed that, among them, arachidic acid, behenic acid, heptadecanoic acid, heneicosanoic acid and pristanic acid may be the key compounds affecting the lipid content. In addition, in the whole process of semen coicis maturation, edible and feeding Coix show similar trends, and changes in the third period show clear compounds in the opposite situation, suggesting that edible and feeding Coix not only guarantee the relative stability of species but also provide raw materials for genetic breeding. This study provides valuable information on the formation of the edible and medicinal qualities of Coix.

Visible light-induced selenylative spirocyclization of biaryl ynones toward the formation of selenated spiro[5.5]trienones.

A visible-light induced dearomative cascade cyclization of biaryl ynones with diselenides under photocatalyst and external additive-free conditions has been explored, giving a series of selenated spiro[5.5]trienones in moderate to good yields. The Se-Se bond in diselenides could be cleaved to generate arylselenyl radicals under visible light irradiation in the absence of a photocatalyst. This protocol provides a facile and green method for the synthesis of spiro[5.5]trienones.

Hierarchically Annular Mesoporous Carbon Derived from Phenolic Resin for Efficient Removal of Antibiotics in Wastewater.

Antibiotics have become a new type of environmental pollutant due to their extensive use. High-performance adsorbents are of paramount significance for a cost-effective and environmentally friendly strategy to remove antibiotics from water environments. Herein, we report a novel annular mesoporous carbon (MCN), prepared by phenolic resin and triblock copolymer F127, as a high-performance adsorbent to remove penicillin, streptomycin, and tetracycline hydrochloride from wastewater. The MCNs have high purity, rich annular mesoporosity, a high surface area (605.53 m2/g), and large pore volume (0.58 cm3/g), improving the adsorption capacity and facilitating the efficient removal of penicillin, streptomycin, and tetracycline hydrochloride from water. In the application of MCNs to treat these three kinds of residual antibiotics, the adsorption amounts of tetracycline hydrochloride were higher than penicillin and streptomycin, and the adsorption capacity was up to 880.6 mg/g. Moreover, high removal efficiency (99.6%) and excellent recyclability were achieved. The results demonstrate that MCN adsorbents have significant potential in the treatment of water contaminated with antibiotics.

Bovine extracellular vesicles contaminate human extracellular vesicles produced in cell culture conditioned medium when 'exosome-depleted serum' is utilised.

Extracellular vesicles (EVs) are important intercellular communication messengers. Half of the published studies in the field are in vitro cell culture based in which bovine serum in various concentrations and forms is used to facilitate the production of extracellular vesicles. 'Exosome depleted serum' is the type of bovine serum most widely used in the production of human EVs. Herein, we demonstrate that, despite the initial caution raised in 2014 about the persistence of bovine EVs, 'exosome depleted serum' was still used in 46% of publications on human or rodent EVs between 2015 and 2019. Using nanoparticle tracking analysis combined with detergent lysis of vesicles as well as bovine CD9 ELISA, we show that there were approximately 5.33 x 107/mL of bovine EVs remaining in the 'exosome depleted serum'. Importantly, the 'exosome depleted serum' was relatively enriched in small EVs by approximately 2.7-fold relative to the large EVs compared to that in the original serum. Specifically, the percentage of small EVs in total vesicles had increased from the original 48% in the serum before ultracentrifugation to 92% in the 'exosome depleted serum'. Furthermore, the pervasive bovine EVs carried over by the 'exosome depleted serum', even when the lowest concentration (0.5%) was used in cell culture, resulted in a significant contamination of human EVs in cell culture conditioned medium. Our findings indicate that the use 'exosome depleted serum' in cell culture-based studies may introduce artefacts into research examining the function of human and rodent EVs, in particular those involving EV miRNA. Thus, we appeal to the researchers in the EV field to seriously reconsider the practice of using 'exosome depleted serum' in the production of human and other mammalian EVs in vitro.

Marine-Source Quorum Quenching Enzyme YtnP to Improve Hygiene Quality in Dental Units.

Biofilm in dental unit water lines may pose a health risk to patients and dental practitioners. An AdiC-like quorum quenching enzyme, YtnP, was cloned from a deep-sea probiotic Bacillus velezensis, and heterologously expressed in E. coli to examine the application on the improvement of hygiene problems caused by biofilm infection of Pseudomonas aeruginosa in dental units. Pseudomonas bacteria were isolated from dental chair units and used to grow static biofilms in the laboratory. A water filter system was designed to test the antifouling activity of YtnP in Laboratory, to simulate the biofilm contamination on water filter in dental unit water lines. The results demonstrated that the enzyme of YtnP was able to degrade the N-acyl homoserine lactones, significantly inhibited the EPS generation, biofilm formation, and virulence factors production (pyocyanin and rhamnolipid) of P. aeruginosa, and was efficient on the antifouling against P. aeruginosa. The findings in this study indicated the possibility of YtnP as novel disinfectant reagent for hygiene treatment in dental units.

Facile Construction of Bio-Based Supramolecular Hydrogels from Dehydroabietic Acid with a Tricyclic Hydrophenanthrene Skeleton and Stabilized Gel Emulsions.

Supramolecular hydrogels have attracted great attention due to their special properties. In this research, bio-based supramolecular hydrogels were conveniently constructed by heating and ultrasounding two components of dehydroabietic acid with a rigid tricyclic hydrophenanthrene skeleton and morpholine. The microstructures and properties of hydrogels were investigated by DSC, rheology, SAXS, CD spectroscopy, and cryo-TEM, respectively. The critical gel concentration (CGC) of the hydrogel was 0.3 mol·L-1 and the gel temperature was 115 °C. In addition, the hydrogel showed good stability and mechanical properties according to rheology results. Cryo-TEM images reveal that the microstructure of hydrogel is fibrous meshes; its corresponding mechanism has been studied using FT-IR spectra. Additionally, oil-in-water gel emulsions were prepared by the hydrogel at a concentration above its CGC, and the oil mass fraction of the oil-in-water gel emulsions could be freely adjusted between 5% and 70%. This work provides a convenient way to prepare bio-based supramolecular hydrogels and provides a new method for the application of rosin.

Microfluidic-Integrated Multicolor Immunosensor for Visual Detection of HIV-1 p24 Antigen with the Naked Eye.

Here, a fully integrated multicolor immunosensor was developed for sensitive and reliable semiquantitative analysis of HIV-1 p24, which integrates the multistep reactions of horseradish peroxidase (HRP)-linked immunoassay and gold nanorod (AuNR)-based multicolor assay into a single microfluidic chip. The HRP-linked immunoassay functions by moving magnetic beads bound to a capture antibody through different aqueous phases containing immunoassay reagents. HRP-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) is used to mediate AuNRs etching for producing various color changes. Multiple etching processes can be activated by simple mixing of the reagents from the reagent storage reservoir. The fully integrated strategy with sample-in answer-out capability is initiated by simple chip manipulation and finally concluded by converting recognition of antigen-antibody into a vivid color variation for direct visualization and semiquantitative analysis. By bare eye observation, our integrated multicolor immunosensor allows sensitive and reliable semiquantitative analysis of HIV-1 p24 within 1 h. The microfluidic chip device demonstrated here simplifies the operation significantly and thus allows broader application of a multicolor immunosensor for point of care (POC) testing in low-resource settings.

Structural Isomerism of Two Ce-BTC for Fabricating Pt/CeO2 Nanorods toward Low-Temperature CO Oxidation.

Metal-organic frameworks (MOFs) have attracted enormous research interest as precursors/templates to prepare catalytic materials. However, the effect of structural isomerism of MOFs on the catalytic performance has rarely been studied. In this contribution, two topologically different Ce-benzene tricarboxylate (Ce-BTC) based on the same ligands and metal centers (viz., "MOF isomers") are prepared and used as porous supports to load Pt nanoparticles (NPs), which shows distinct differences in porosities and loading behaviors of Pt. Strikingly, an irreversible framework transformation from tetragonal Ce-BTC to monoclinic isomer is observed during water soaking treatment. The results give clear evidence that Pt/CeO2 derived from tetragonal Ce-BTC inclines to produce more Pt0 and smaller Pt NPs, which eventually improve the catalytic performance for CO oxidation (T100 = 80 °C). In situ diffuse reflectance infrared Fourier transform spectroscopy analyses demonstrate that the adsorbed CO-Pt0 is the dominant intermediate for CO oxidation, rather than CO-Ptσ + at the low temperature. Furthermore, MOF isomers based on the same structural units are also found in other Ln-MOFs, such as Er-BTC, Eu-BTC, Y-BTC, and Ce/Y-BTC. Overall, this study affords a fundamental understanding of the effect of MOF structural isomers on the catalytic performance of the derived composites.

Proteomics reveals a therapeutic vulnerability via the combined blockade of APE1 and autophagy in lung cancer A549 cells.

BACKGROUND: Drug resistance is a major cause of therapeutic failure that is often associated with elevated autophagy and apurinic/apyrimidinic endonuclease 1 (APE1) expression. Herein, we investigated the role of APE1 and autophagy in A549 cells treated with cisplatin. METHODS: SILAC proteomics was applied to obtain a panoramic view of cisplatin treatment in KRASG12S-mutant A549 cells. Quantity analysis of cellular apoptosis and autophagy was based on flow cytometry. Western blotting was used to examine the expression levels of apoptosis- and autophagy-related proteins, as well as those of APE1. Knockdown of APE1 was achieved by RNA interference. Immunoprecipitation was further employed to reveal the molecular interaction of APE1, p53, and LC3 when A549 cells were exposed to cisplatin. RESULTS: SILAC proteomics revealed that 72 canonical pathways, including base excision repair (BER) and autophagy signalling pathways, were regulated after cisplatin treatment in A549 cells. Cisplatin markedly induced autophagy and apoptosis in A549 cells, accompanied by remarkable APE1 increase. Suppression of autophagy enhanced the inhibition effect of cisplatin on cell growth, proliferation, and colony formation; however, APE1 inhibition enhanced the expression of LC3-I/II, suggesting that APE1 and autophagy are compensatory for cell survival to evade the anticancer action of cisplatin. Immunoprecipitation results revealed the triple complex of APE1-p53-LC3 in response to cisplatin plus CQ in A549 cells. Dual inhibition of APE1 and autophagy significantly enhanced cisplatin-induced apoptosis, which eventually overcame drug resistance in cisplatin-resistant A549 cells. CONCLUSIONS: Dual inhibition of APE1 and autophagy greatly enhances apoptosis in parental KRASG12S-mutant A549 cells and cisplatin-resistant A549 cells via regulation of APE1-p53-LC3 complex assembly, providing therapeutic vulnerability to overcome cisplatin resistance in the context of KRASG12S-mutant lung cancer.

Synthesis of ZIF-8 Nanocrystals Mediated by CO2 Gas Bubbling: Dissolution and Recrystallization.

Crystal size and morphology of zeolitic imidazolate frameworks (ZIFs) can be generally controlled based on the classical theory of nucleation and growth. Herein, we have developed an alternative method to adjust the nucleation and growth kinetics of microporous ZIF-8 nanocrystals mediated by continuous CO2 gas bubbling. In particular, CO2 bubbling led to the dissolution of ZIF-8 slurry, while the evacuation of CO2 bubbling resulted in the formation of new ZIF-8 nanoparticles with a considerably smaller size. A plausible mechanism of the CO2-mediated synthesis of ZIF-8 nanoparticles was proposed based on comprehensive characterizations and analyses, which indicated that the dissolved CO2 in methanol was able to perturb the pre-equilibrium states of crystallization intermediates and led to a comparatively fast nucleation rate due to a low number of overcoordinated species between the metal ion and the ligand. Both methanol and the base were critically important to the dissolution-recrystallization of ZIF-8, wherein the methyl carbonate linker might be reversibly produced by CO2 insertion into the methoxide group (Zn-OCH3). Also, the CO2-mediated synthesis led to the small particle size, high crystallinity, good thermal stability, and high purity of ZIF-8, as compared to the conventional ZIF-8 prepared without CO2 gas bubbling. As proof of workability, the prepared monodispersed ZIF-8 nanoparticles showed a much higher photocatalytic activity toward various organic dyes' decomposition than the conventional ZIF-8. Also, the CO2 bubbling-mediated method could be further extended to prepare other ZIFs (e.g., ZIF-67).

Loss of Bmi1 causes anomalies in retinal development and degeneration of cone photoreceptors.

Retinal development occurs through the sequential but overlapping generation of six types of neuronal cells and one glial cell type. Of these, rod and cone photoreceptors represent the functional unit of light detection and phototransduction and are frequently affected in retinal degenerative diseases. During mouse development, the Polycomb group protein Bmi1 is expressed in immature retinal progenitors and differentiated retinal neurons, including cones. We show here that Bmi1 is required to prevent post natal degeneration of cone photoreceptors and bipolar neurons and that inactivation of Chk2 or p53 could improve but not overcome cone degeneration in Bmi1(-/-) mice. The retinal phenotype of Bmi1(-/-) mice was also characterized by loss of heterochromatin, activation of tandem repeats, oxidative stress and Rip3-associated necroptosis. In the human retina, BMI1 was preferentially expressed in cones at heterochromatic foci. BMI1 inactivation in human embryonic stem cells was compatible with retinal induction but impaired cone terminal differentiation. Despite this developmental arrest, BMI1-deficient cones recapitulated several anomalies observed in Bmi1(-/-) photoreceptors, such as loss of heterochromatin, activation of tandem repeats and induction of p53, revealing partly conserved biological functions between mouse and man.

Catalase-linked immunosorbent pressure assay for portable quantitative analysis.

In this study, catalase-linked immunosorbent pressure assay with a gas-generation reaction was established for quantitative detection of disease biomarker C-reactive protein (CRP) by a portable pressuremeter. The pressure-based detection system recognizes, transduces, and amplifies the target signal to a convenient target-correlated pressure signal reading in a closed chamber. Biotin molecules were modified on the surface of catalase in order to incorporate catalase into the pressure immunoassay by the streptavidin-biotin interaction. To improve the assay performance, the modification ratios of biotin molecules to catalase, and the concentrations of capture and detection antibodies were further optimized. The catalase-linked immunosorbent pressure assay allows portable and quantitation analysis of CRP with a limit of detection of 1.8 nM, which can satisfy the clinical needs for determining the risk of cardiovascular disease. The catalase-linked immunosorbent pressure assay also shows superior specificity and good accuracy. Compared to the previously reported assay catalyzed by PtNP nanozyme, catalase is not easily deactivated during storage and operation. With the merits of enzymatic efficiency, biocompatibility, low non-specific adsorption and facile modification, catalase can be reasonably used for reproducible, stable, simple quantitative detection of disease markers using a portable pressure-based assay in resource-limited settings.

Soluble (pro)renin receptor via ß-catenin enhances urine concentration capability as a target of liver X receptor.

The extracellular domain of the (pro)renin receptor (PRR) is cleaved to produce a soluble (pro)renin receptor (sPRR) that is detected in biological fluid and elevated under certain pathological conditions. The present study was performed to define the antidiuretic action of sPRR and its potential interaction with liver X receptors (LXRs), which are known regulators of urine-concentrating capability. Water deprivation consistently elevated urinary sPRR excretion in mice and humans. A template-based algorithm for protein-protein interaction predicted the interaction between sPRR and frizzled-8 (FZD8), which subsequently was confirmed by coimmunoprecipitation. A recombinant histidine-tagged sPRR (sPRR-His) in the nanomolar range induced a remarkable increase in the abundance of renal aquaporin 2 (AQP2) protein in primary rat inner medullary collecting duct cells. The AQP2 up-regulation relied on sequential activation of FZD8-dependent ß-catenin signaling and cAMP-PKA pathways. Inhibition of FZD8 or tankyrase in rats induced polyuria, polydipsia, and hyperosmotic urine. Administration of sPRR-His alleviated the symptoms of diabetes insipidus induced in mice by vasopressin 2 receptor antagonism. Administration of the LXR agonist TO901317 to C57/BL6 mice induced polyuria and suppressed renal AQP2 expression associated with reduced renal PRR expression and urinary sPRR excretion. Administration of sPRR-His reversed most of the effects of TO901317. In cultured collecting duct cells, TO901317 suppressed PRR protein expression, sPRR release, and PRR transcriptional activity. Overall we demonstrate, for the first time to our knowledge, that sPRR exerts antidiuretic action via FZD8-dependent stimulation of AQP2 expression and that inhibition of this pathway contributes to the pathogenesis of diabetes insipidus induced by LXR agonism.

Self-Assembly of Functional Nucleic Acid-Based Colorimetric Competition Assay for the Detection of Immunoglobulin E.

In this work, we have developed a simple and rapid colorimetric assay for the detection of immunoglobulin E (IgE) using functional nucleic acids (FNAs) and a solid-phase competition enzyme-linked immunosorbent assay (ELISA). The FNAs including aptamer of recombinant IgE, G-quadruplex and its complementary fragments were immobilized on 96-well microplates to achieve recognition and detection of IgE in biological samples. The G-quadruplex DNAzyme catalyzed 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)-hemin-H2O2 system was used to improve the sensitivity of colorimetric assay. In the presence of IgE, the hairpin structure and G-quadruplex would be destroyed, resulting in the inactivation of DNAzyme and subsequent reduction of its absorbance. This cost-effective approach detected IgE in the linear range from 5.0 pg/mL to 500 ng/mL, with the limit of detection (LOD) of 2.0 pg/mL, under optimal conditions. Moreover, the developed method was successfully applied to the rapid detection of IgE in human urine, indicating a great potentiality of this approach in clinical diagnosis and other biomedical applications.

Dual-Responsive Alginate Hydrogels for Controlled Release of Therapeutics.

In this work, with the drug oxytetracycline (OTC) released, cell cytotoxicity and antimicrobial studies of dual-responsive sodium alginate and N-Isopropylacrylamide hydrogels (SA/pNIPAAm) with enclosed OTC were investigated. The molecular OTC release was explored with different acid-base conditions and temperature conditions. In order to characterize cell cytotoxicity and antimicrobial efficacy, time-dependent OTC release analysis of different acid-base conditions was performed in SA/pNIPAAm hydrogels. OTC@SA/pNIPAAm hydrogels showed excellent time-dependent antimicrobial efficacy, in which the IC50 values were 50.11 µg mL-1, 34.27 µg mL-1, and 22.39 µg mL-1 among three consecutive days, respectively. Meanwhile, the human cells showed excellent viability at the IC50 dosage of OTC@SA/pNIPAAm (50.11 µg mL-1). OTC@SA/pNIPAAm performed in this study indicated that SA/pNIPAAm may serve as drug carriers for sustainable release at a specific concentration and for being employed as substrates for decreasing drug toxicity. Besides, pH-responsive and thermos-responsive SA/pNIPAAm may lead to the better selectivity of drug release in the ideal location or site. Finally, the results demonstrate that the designed, dual-responsive, biocompatible OTC@SA/pNIPAAm hydrogels showed excellent antimicrobial efficacy and may potentially be found to have enormous applicability in the field of pharmaceutics.

Differentiation of human embryonic stem cells into cone photoreceptors through simultaneous inhibition of BMP, TGFß and Wnt signaling.

Cone photoreceptors are required for color discrimination and high-resolution central vision and are lost in macular degenerations, cone and cone/rod dystrophies. Cone transplantation could represent a therapeutic solution. However, an abundant source of human cones remains difficult to obtain. Work performed in model organisms suggests that anterior neural cell fate is induced 'by default' if BMP, TGFß and Wnt activities are blocked, and that photoreceptor genesis operates through an S-cone default pathway. We report here that Coco (Dand5), a member of the Cerberus gene family, is expressed in the developing and adult mouse retina. Upon exposure to recombinant COCO, human embryonic stem cells (hESCs) differentiated into S-cone photoreceptors, developed an inner segment-like protrusion, and could degrade cGMP when exposed to light. Addition of thyroid hormone resulted in a transition from a unique S-cone population toward a mixed M/S-cone population. When cultured at confluence for a prolonged period of time, COCO-exposed hESCs spontaneously developed into a cellular sheet composed of polarized cone photoreceptors. COCO showed dose-dependent and synergistic activity with IGF1 at blocking BMP/TGFß/Wnt signaling, while its cone-inducing activity was blocked in a dose-dependent manner by exposure to BMP, TGFß or Wnt-related proteins. Our work thus provides a unique platform to produce human cones for developmental, biochemical and therapeutic studies and supports the hypothesis that photoreceptor differentiation operates through an S-cone default pathway during human retinal development.

Evolutionary conservation and functional divergence of the LFK gene family play important roles in the photoperiodic flowering pathway of land plants.

ZEITLUPE (ZTL), LOV KELCH PROTEIN 2 (LKP2), and FLAVIN-BINDING KELCH REPEAT F-BOX 1 (FKF1)-blue-light photoreceptors-play important roles in regulating the circadian clock and photoperiodic flowering pathway in plants. In this study, phylogenetic analysis revealed that the LOV (Light, Oxygen, or Voltage) and Kelch repeat-containing F-box (LFK) gene family can be classified into two clades, ZTL/LKP2 and FKF1, with clear differentiation between monocots and dicots within each clade. The LFK family genes underwent strong purifying selection; however, signatures of positive selection to adapt to local conditions still existed in 18 specific codons. In 87 diverse maize inbred lines, significant differences were identified (P ≤ 0.01) for days to female flowering between the haplotypes consisting of eight positive selection sites at ZmFKF1b corresponding to tropical and temperate maize groups of the phylogenetic tree, indicating a key role of ZmFKF1b in maize adaptive evolution. In addition, positive coevolution was detected in the domains of the LFK family for long-term cooperation to targets. The Type-I and Type-II functional divergence analysis revealed subfunctionalization or neofunctionalization of the LFKs, and the ZTL subfamily is most likely to maintain the ancestral function of LFKs. Over 50% of critical amino acid sites involved in the functional divergence were identified in the Kelch repeat domain, resulting in the distinction of substrates for ubiquitination and degradation. These results suggest that evolutionary conservation contributes to the maintenance of critical physiological functions, whereas functional divergence after duplication helps to generate diverse molecular regulation mechanisms.

Collecting duct (pro)renin receptor targets ENaC to mediate angiotensin II-induced hypertension.

The (pro)renin receptor (PRR) is abundantly expressed in the collecting duct (CD) and the expression is further induced by angiotensin II (ANG II). The present study was conducted to investigate the role of CD PRR during ANG II-induced hypertension and to further explore the underlying mechanism. Radiotelemetry demonstrated that a 1-wk ANG II infusion gradually and significantly induced hypertensive response in floxed mice and this response was significantly attenuated in mice lacking PRR in the CD (termed CD PRR KO). ANG II infusion in floxed mice increased urinary renin activity and selectively induced renal medullary α-epithelial sodium channel (α-ENaC) mRNA and protein expression, all of which were blunted in the null mice. In cultured mpkCCD cells grown in Transwells, transepithelial Na+ transport as measured by using a volt-ohmmeter was transiently stimulated by acute ANG II treatment, which was abolished by a PRR antagonist, PRO20. In a chronic setting, ANG II treatment induced α-ENaC mRNA expression in mpkCCD cells, which was similarly blocked by PRO20. Chronic intramedullary infusion of an ENaC inhibitor amiloride in rats significantly attenuated ANG II-induced hypertension. Overall, the present study suggests that CD PRR contributes to ANG II-induced hypertension at least partially via activation of renal medullary ENaC.

Biochemical mechanism underlying hypertriglyceridemia and hepatic steatosis/hepatomegaly induced by acute schisandrin B treatment in mice.

BACKGROUND: It has been demonstrated that acute oral administration of schisandrin B (Sch B), an active dibenzocyclooctadiene isolated from Schisandrae Fructus (a commonly used traditional Chinese herb), increased serum and hepatic triglyceride (TG) levels and hepatic mass in mice. The present study aimed to investigate the biochemical mechanism underlying the Sch B-induced hypertriglyceridemia, hepatic steatosis and hepatomegaly. METHODS: Male ICR mice were given a single oral dose of Sch B (0.25-2 g/kg). Sch B-induced changes in serum levels of biomarkers, such as TG, total cholesterol (TC), apolipoprotein B48 (ApoB 48), very-low-density lipoprotein (VLDL), non-esterified fatty acid (NEFA) and hepatic growth factor (HGF), as well as hepatic lipids and mass, epididymal adipose tissue (EAT) and adipocyte size, and histological changes of the liver and EAT were examined over a period of 12-120 h after Sch B treatment. RESULTS: Serum and hepatic TG levels were increased by 1.0-4.3 fold and 40-158% at 12-72 h and 12-96 h, respectively, after Sch B administration. Sch B treatment elevated serum ApoB 48 level (up to 12%), a marker of exogenous TG, but not VLDL, as compared with the vehicle treatment. Treatment with Sch B caused a time-/dose-dependent reduction in EAT index (up to 39%) and adipocyte size (up to 67%) and elevation in serum NEFA level (up to 55%). Sch B treatment induced hepatic steatosis in a time-/dose-dependent manner, as indicated by increases in total vacuole area (up to 3.2 fold vs. the vehicle control) and lipid positive staining area (up to 17.5 × 103 µm2) in liver tissue. Hepatic index and serum HGF levels were increased by 18-60% and 42-71% at 12-120 h and 24-72 h post-Sch B dosing, respectively. In addition, ultrastructural changes, such as increase in size and disruption of cristae, in hepatic mitochondria were observed in Sch B-treated mice. CONCLUSION: Our findings suggest that exogenous sources of TG and the breakdown of fat storage in the body contribute to Sch B-induced hypertriglyceridemia and hepatic steatosis in mice. Hepatomegaly (a probable hepatotoxic action) caused by Sch B may result from the fat accumulation and mitochondrial damage in liver tissue.