Dimerization and antidepressant recognition at noradrenaline transporter.

The noradrenaline transporter has a pivotal role in regulating neurotransmitter balance and is crucial for normal physiology and neurobiology1. Dysfunction of noradrenaline transporter has been implicated in numerous neuropsychiatric diseases, including depression and attention deficit hyperactivity disorder2. Here we report cryo-electron microscopy structures of noradrenaline transporter in apo and substrate-bound forms, and as complexes with six antidepressants. The structures reveal a noradrenaline transporter dimer interface that is mediated predominantly by cholesterol and lipid molecules. The substrate noradrenaline binds deep in the central binding pocket, and its amine group interacts with a conserved aspartate residue. Our structures also provide insight into antidepressant recognition and monoamine transporter selectivity. Together, these findings advance our understanding of noradrenaline transporter regulation and inhibition, and provide templates for designing improved antidepressants to treat neuropsychiatric disorders.

2D fin field-effect transistors integrated with epitaxial high-k gate oxide.

Precise integration of two-dimensional (2D) semiconductors and high-dielectric-constant (k) gate oxides into three-dimensional (3D) vertical-architecture arrays holds promise for developing ultrascaled transistors1-5, but has proved challenging. Here we report the epitaxial synthesis of vertically aligned arrays of 2D fin-oxide heterostructures, a new class of 3D architecture in which high-mobility 2D semiconductor fin Bi2O2Se and single-crystal high-k gate oxide Bi2SeO5 are epitaxially integrated. These 2D fin-oxide epitaxial heterostructures have atomically flat interfaces and ultrathin fin thickness down to one unit cell (1.2 nm), achieving wafer-scale, site-specific and high-density growth of mono-oriented arrays. The as-fabricated 2D fin field-effect transistors (FinFETs) based on Bi2O2Se/Bi2SeO5 epitaxial heterostructures exhibit high electron mobility (µ) up to 270 cm2 V-1 s-1, ultralow off-state current (IOFF) down to about 1 pA µm-1, high on/off current ratios (ION/IOFF) up to 108 and high on-state current (ION) up to 830 µA µm-1 at 400-nm channel length, which meet the low-power specifications projected by the International Roadmap for Devices and Systems (IRDS)6. The 2D fin-oxide epitaxial heterostructures open up new avenues for the further extension of Moore's law.

Growth of single-crystal black phosphorus and its alloy films through sustained feedstock release.

Black phosphorus (BP), a fascinating semiconductor with high mobility and a tunable direct bandgap, has emerged as a candidate beyond traditional silicon-based devices for next-generation electronics and optoelectronics. The ability to grow large-scale, high-quality BP films is a prerequisite for scalable integrated applications but has thus far remained a challenge due to unmanageable nucleation events. Here we develop a sustained feedstock release strategy to achieve subcentimetre-size single-crystal BP films by facilitating the lateral growth mode under a low nucleation rate. The as-grown single-crystal BP films exhibit high crystal quality, which brings excellent field-effect electrical properties and observation of pronounced Shubnikov-de Haas oscillations, with high mobilities up to ~6,500 cm2 V-1 s-1 at low temperatures. We further extend this approach to the growth of single-crystal BP alloy films, which broaden the infrared emission regime of BP from 3.7 µm to 6.9 µm at room temperature. This work will greatly facilitate the development of high-performance electronics and optoelectronics based on BP family materials.

Utility of multidetector computed tomography quantitative measurements in identifying sarcopenia: a propensity score matched study.

OBJECTIVE: To evaluate the utility of multidetector computed tomography MDCT quantitative measurements in identifying sarcopenia. MATERIALS AND METHODS: The clinical data and MDCT images of 64 patients of sarcopenia and 184 non-sarcopenic participants between October 2020 and January 2021were retrospectively analyzed. Propensity score matching was used to match the sarcopenic patients with the non-sarcopenic participants. Two radiologists independently measured the cross-sectional area (CSA) of skeletal muscle and intramuscular fat tissue and CT density of skeletal muscle at the middle L3 vertebral level on CT images of all participants. Intra-observer agreement was evaluated via intraclass correlation coefficients (ICC). A receiver operating characteristic (ROC) curve was built for each variable. Correlations between CT parameters and clinical data were assessed via Pearson or Spearman correlation coefficient. RESULTS: A total of 74 participants (mean age 72 ± 4 years, range 66-85 years; 38 men and 36 women) were included, comprising 37 sarcopenic patients and 37 non-sarcopenic participants. There were no significant intergroup differences regarding age, sex ratio, and body mass index (BMI) (P < 0.05). The CSA and density of skeletal muscle measured by two radiologists were reliable (ICC ≥ 0.75, P < 0.001). Compared with the sarcopenic group, the non-sarcopenic group had a significantly greater CSA and CT density of the total skeletal muscle (TSM) and paraspinal skeletal muscle (PSM) and skeletal muscle index at L3 level (L3 SMI) (P < 0.05). The fat infiltration ratio (FIR) of TSM, PSM, and psoas muscle was significantly higher in the sarcopenic group than that in non-sarcopenic participants (P < 0.05). ROC curve analysis showed the PSM FIR + PSM CT density (PSM D) had the best predictive value for sarcopenia (AUC = 0.836). The PSM FIR and age were moderately positively correlated (r = 0.410, P < 0.001). CONCLUSION: Fat infiltration of skeletal muscle had better predictive value than L3 SMI in the diagnosis of sarcopenic. The PSM FIR + PSMD had the best predictive value for sarcopenia, which was moderately positively correlated with age.

Ligand-induced activation of ERK1/2 signaling by constitutively active Gs-coupled 5-HT receptors.

5-HT4R, 5-HT6R, and 5-HT7AR are three constitutively active Gs-coupled 5-HT receptors that have key roles in brain development, learning, memory, cognition, and other physiological processes in the central nervous system. In addition to Gs signaling cascade mediated by these three 5-HT receptors, the ERK1/2 signaling which is dependent on cyclic adenosine monophosphate (cAMP) production and protein kinase A (PKA) activation downstream of Gs signaling has also been widely studied. In this study, we investigated these two signaling pathways originating from the three Gs-coupled 5-HT receptors in AD293 cells. We found that the phosphorylation and activation of ERK1/2 are ligand-induced, in contrast to the constitutively active Gs signaling. This indicates that Gs signaling alone is not sufficient for ERK1/2 activation in these three 5-HT receptors. In addition to Gs, we found that ß-arrestin and Fyn are essential for the activation of ERK1/2. Together, these results put forth a novel mechanism for ERK1/2 activation involving the cooperative action of Gs, ß-arrestin, and Fyn.

Alterations of the oral microbiome in patients treated with the Invisalign system or with fixed appliances.

INTRODUCTION: Although the Invisalign system has been used widely in recent years, the influences of this treatment on the oral microbiome and whether or not this influence is different from that of fixed appliances is still unknown. In this study, we investigated the changes in the oral microbiome in patients treated with the Invisalign system or with fixed appliances. METHODS: Fifteen subjects were enrolled, comprising 5 fixed appliance patients, 5 Invisalign patient, and 5 healthy controls. Saliva samples were collected, and high-throughput pyrosequencing was performed based on the 16S rRNA gene. RESULTS: Both fixed and Invisalign orthodontic treatments resulted in dysbiosis of the oral microbiome. Firmicutes and TM7 at the phyla level and Neisseria at the genus level displayed statistically significant differences between the 2 orthodontic groups. The effect of these changes with microbiome on oral health was inconsistent. The inferred microbial function of the Invisalign group suggested this group was more predisposed to periodontal diseases. CONCLUSION: The influence of the Invisalign system on the oral microbiome was no better for oral health compared with fixed appliances. The convenience of maintaining oral hygiene rather than changes in the oral microbiome may be the underlying reason for the performance of the Invisalign system on oral health.

[Correlation of single nucleotide polymorphisms rs995030 and rs4474514 of the KITLG gene with male infertility].

OBJECTIVE: To investigate the correlation of the single nucleotide polymorphisms rs995030 and rs4474514 of the tyrosine kinase receptor-specific ligand (KITLG) gene with the risk of male infertility. METHODS: This study included 360 patients with idiopathic male infertility and 338 healthy fathers as controls, all from the surrounding areas of Nanjing. According to the 5th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen, we divided the infertility patients into an azoospermia (n = 143), a severe oligozoospermia (n = 159), and an oligozoospermia group (n = 58). We obtained the basic clinical data on all the subjects, collected genomic DNA from the peripheral blood of the patients, determined the genotypes of the KITLG gene rs995030 and rs4474514 by sequence mass-array, and analyzed the correlation between the two-point gene polymorphism and male infertility by logistic regression analysis. RESULTS: Statistically significant differences were observed between the infertility patients and normal fertile controls in sperm concentration (ï¼»13.23 ± 24.52ï¼½ vs ï¼»78.74 ± 61.25ï¼½ ×106/ml, P < 0.01), the percentage of progressively mobile sperm (ï¼»18.71 ± 15.19ï¼½% vs ï¼»39.36 ± 9.75ï¼½%, P < 0.01), and the level of FSH (ï¼»16.09 ± 17.31ï¼½ vs ï¼»4.56 ± 2.41ï¼½ IU/L, P < 0.01), but not between the genotypes and male infertility, and no correlation was found in subgroup analysis. CONCLUSIONS: The single nucleotide polymorphisms rs995030 and rs4474514 of the KITLG gene were not significantly correlated with male infertility, which is to be further verified by more studies with samples of larger size and expanded selection range.

[Multiplex fluorescence PCR for detection of Y Chromesome microdeletions].

OBJECTIVE: Detection of azoospermia factor (AZF) microdeletions on the Y chromosome is one of the auxiliary strategies recognized at home and abroad for the examination of male infertility. Traditional PCR gel electrophoresis fails to meet the clinical needs due to its shortcomings. The purpose of this study was to explore the feasibility of multiplex fluorescence PCR in the detection of AZF microdeletions. METHODS: We collected samples of Y chromosomal AZF microdeletions from 238 patients with azoospermia or oligozoospermia and 62 normal males, identified the 14 short tandem repeat (STR) loci in the AZF region of the Y chromosome by multiplex PCR gel electrophoresis and multiplex fluorescence PCR, and analyzed the consistency in the results of the two methods by Kappa test. RESULTS: There was a perfect consistency between multiplex PCR gel electrophoresis and multiplex fluorescence PCR in the detection rate of the STR loci in the 300 samples. Kappa test showed both P and Kappa values to be 1 for the 6 loci in the AZFa, AZFb and AZFc regions of the Y chromosome, with no statistically significant difference between the two methods. CONCLUSIONS: Multiplex fluorescence PCR can save a lot of time, reduce workload and improve laboratory efficiency and therefore is preferable to multiplex PCR gel electrophoresis in detecting Y chromosome microdeletions.

[Correlation of the single nucleotide polymorphisms rs34349826 and rs6521 of the LHB gene with male infertility in Chinese men].

Objective: To study the relationship of the single nucleotide polymorphisms (SNP) rs34349826 (c.104 A>G) and rs6521 (c.114 C>G) of the luteinizing hormone beta-subunit (LHB) gene with male infertility in Chinese men. METHODS: This case-control study included 405 males with primary infertility (the infertility group) and 424 normal fertile men (the control group), the former again divided into subgroups of oligospermia, severe oligozoospermia and azoospermia according to the sperm concentration. Clinical data were collected from all the subjects and genomic DNA obtained from their peripheral blood for genotyping rs34349826 and rs6521 of the LHB gene by Sequence MassArray. We analyzed the correlation of male infertility with the SNPs of the two loci using the logistic regression model as well as its association with their haplotype combination with the SHEsis online software. RESULTS: There were statistically significant differences between the control and infertility groups in the semen volume (ï¼»3.51 ± 1.36ï¼½ vs ï¼»3.74 ± 1.71ï¼½ ml, P <0.05), sperm concentration (ï¼»79.21 ± 61.60ï¼½ vs ï¼»27.37 ± 30.80ï¼½ ×106/ml, P <0.01), percentage of progressively motile sperm (ï¼»39.40 ± 9.64ï¼½ % vs ï¼»11.90 ± 14.72ï¼½ %, P <0.01), and levels of serum luteinizing hormone (LH) (ï¼»3.29 ± 1.39ï¼½ vs ï¼»6.25 ± 4.83ï¼½ IU/L, P <0.01) and follicle-stimulating hormone (FSH) (ï¼»4.56 ± 2.31ï¼½ vs ï¼»15.64 ± 17.03ï¼½ IU/L, P <0.01). Logistic regression analysis revealed no correlation between male infertility and the genotypes of the rs34349826 and rs6521 loci of the LHB gene, and similar results were found in the subgroups of the infertile males. SHEsis analysis on the haplotypes of the rs34349826 and rs6521 loci showed the GG genotype combination to be a protective factor against male infertility. CONCLUSIONS: The rs34349826 and rs6521 loci of the LHB gene were not related to male infertility, which can be further confirmed by larger-sample studies. The GG genotype combination is a protective factor against male infertility.

Generation and Screening of T-DNA Insertion Mutants Mediated by Agrobacterium tumefaciens in the Garden Asparagus Stem Blight Pathogen Phomopsis asparagi.

The garden asparagus stem blight caused by filamentous fungus Phomopsis asparagi exposes a serious threat on asparagus production globally. However, to present, we understand poorly about the molecular mechanisms of fungal pathogenicity. To facilitate functional genomics research of P. asparagi, here we developed a highly efficient and stable Agrobacterium tumefaciens-mediated transformation approach which yielded 150-200 transformants per 1 × 106 conidia. Our results indicated that 25 °C, acetosyringone concentration of 150 µmol/L, and 72 h were recommended as optimal co-cultivation conditions for the transformation. Using this transformation approach, we constructed a T-DNA insertion mutant library containing 1253 strains. Twenty randomly selected T-DNA insertion mutants were able to grow on 0.2 × PDA selective media after five successive subcultures without selective pressure, indicating that the exogenous T-DNA was stably integrated into the P. asparagi genome. We confirmed several randomly selected mutants using PCR with primers specific to the hph gene. Southern blots suggested that three out of the five selected mutants have a single T-DNA insertion. Interestingly, multiple mutant candidates with growth defects were obtained from the growth assay. Moreover, several mutants were selected for further analysis on the T-DNA flanking sequences through TAIL-PCR analysis. A sequence comparison of total junction fragments implied that the insertion of T-DNA within P. asparagi genome appeared to be a random event. The transformation technology and genetic resources developed here will facilitate studies of pathogenic mechanisms in this devastating filamentous fungal pathogen of garden asparagus.

Protective Effects of Fucoidan on Aß25-35 and d-Gal-Induced Neurotoxicity in PC12 Cells and d-Gal-Induced Cognitive Dysfunction in Mice.

Alzheimer's disease (AD) is a chronic neurodegenerative disease which contributes to memory loss and cognitive decline in the elderly. Fucoidan, extracted from brown algae, is a complex sulfated polysaccharide and potential bioactive compound. In this study, we investigated whether fucoidan protects PC12 cells from apoptosis induced by a combination of beta-amyloid 25-35 (Aß25-35) and d-galactose (d-Gal), and improves learning and memory impairment in AD model mice. The results indicated that fucoidan could inhibit the release of cytochrome c from the mitochondria to cytosol and activation of caspases, and increase the expression of apoptosis inhibitor proteins (IAPs), including livin and X-linked IAP (XIAP) in PC12 cells damaged by Aß25-35 and d-Gal-induction. Fucoidan reversed the decreased activity of acetylcholine (ACh) and choline acetyl transferase (ChAT), as well as the increased activity of acetylcholine esterase (AChE), in AD model mice induced by infusion of d-Gal. Furthermore, fucoidan improved antioxidant activity in vitro and in vivo by activation of superoxide dismutase (SOD) and glutathione (GSH). These results suggested that fucoidan could protect PC12 cells from apoptosis and ameliorate the learning and memory impairment in AD model mice, which appeared to be due to regulating the cholinergic system, reducing oxidative stress, and inhibiting the caspase-dependent apoptosis pathway.

Effects of polysaccharide from Physalis alkekengi var. francheti on liver injury and intestinal microflora in type-2 diabetic mice.

CONTEXT: Diabetic liver injury is a serious diabetic complication. The alterations of intestinal microbiota play an important role in induction and promotion of liver injury progression. Physalis alkekengi L. var. francheti (Mast.) Makino (Solanaceae) has been used as a water decoction for treating diabetes. OBJECTIVE: To study the effects of a polysaccharide (PPSB) from Physalis alkekengi var. francheti on liver injury and intestinal microflora in type-2 diabetic mice. MATERIALS AND METHODS: Streptozotocin (160 mg/kg) was injected i.p. for 3 days to build model. The diabetic mice were randomly divided into four groups together with control group (10 mice in each group). The doses of PPSB were 50 and 100 mg/kg, respectively. After 5 weeks administration, level of blood glucose, ALT and AST were measured. Alterations of intestinal microflora, and protein expression of TGF-ß1, TNF-α and DCN were detected. RESULTS: Level of blood glucose decreased from (25.38 ± 2.21) mmol/L to (18.01 ± 2.53) mmol/L, ALT and AST decreased to (24.67 ± 4.86) U/L and (30.84 ± 7.50) U/L in PPSB-H group. Lactobacillus, Clostridium butyricum, and Bacteroides increased remarkably with increasing concentration of PPSB, but Enterobacter was inhibited. The relative expression of TGF-ß1 and TNF-α decreased to (0.70 ± 0.17) and (0.39 ± 0.06), and the expression of DCN increased to (0.65 ± 0.13). DISCUSSION AND CONCLUSIONS: Probiotics have been promoted by PPSB, and protein expressions have been modulated in the progression of liver injury. PPSB could be used as a natural agent for treating diabetic liver injury and intestinal microflora imbalance.

Effects of Maydis stigma polysaccharide on the intestinal microflora in type-2 diabetes.

CONTEXT: Diabetes is a serious endocrine and metabolic disorder. Food supplements attract people's attention in mitigating health problems from the aspect of gastrointestinal microflora. Maydis stigma (Zea mays subsp. mays L. [Poaceae]), has been used as water decoction for treating diabetes in folk medicine. It has great potential, and feasibly a stable form of Maydis stigma commercial products could be developed to fulfil the health food market. OBJECTIVE: To study the effects of Maydis stigma polysaccharide (MSP) on the intestinal microflora in type-2 diabetes (T2D). MATERIALS AND METHODS: MSP was fractioned from Maydis stigma by distilled water, purified by DEAE-52 Cellulose chromatography and Sephadex G-200 gel column. Streptozotocin (160 mg/kg) was intraperitoneal injected for 3 days to build model. The diabetic mice were randomly divided into five groups together with control group (10 mice in each group). The doses of MSP were 400, 600 and 800 mg/kg, respectively. After 5 weeks of administration, antidiabetic effects and intestinal microflora balance restoring activities were evaluated by denaturing gradient gel electrophoresis. RESULTS: Blood glucose levels of MSP-treated groups showed extremely significant hypoglycemic effects (p < 0.01), body weight increased showed extremely significant (p < 0.01) differences. Bacteroides, Lactobacillus and Prevotella were dominant organisms in the intestinal tract. The quality and quantity of Lactobacillus and Bacteroides genus increased remarkably with increasing concentration of MSP. DISCUSSION AND CONCLUSION: Experimental results of this study suggest that MSP has the significant potential to be used as a natural agent for treating T2D and restoring the intestinal microflora balance.

Local corticosteroid injection versus physical therapy for the treatment of carpal tunnel syndrome: A systematic review and meta-analysis of randomized controlled trials.

The comparative effect of commonly used conservative treatments for carpal tunnel syndrome remained controversial. The purpose of this study was to compare the clinical effect of local corticosteroid injection and physical therapy for the treatment of carpal tunnel syndrome. A systematic literature search of PubMed, EMBASE, and Cochrane library was conducted to identify relevant randomized clinical trials published before 21st Mar 2023. Two independent reviewers assayed quality of included studies using the Cochrane collaboration risk of bias tool. Relevant data were extracted and pooled analyses were conducted. Outcome measurements included Boston Carpal Tunnel Syndrome Questionnaire, visual analogue scale and some electrophysiology tests, while the former two were set as the primary outcomes. Subgroup analysis and sensitive analysis were performed and publication bias was evaluated. Heterogeneity among the included studies was examined using the I2 statistic. After selection, 12 studies were identified eligibility for inclusion. Only one study was found to have a high risk of bias. Pooled data of primary outcomes did not show any differences between treatments, and subgroup analysis supported the results. However, patients treated with local corticosteroid injection showed better improvement in distal motor latency (p = 0.002) and compound muscle action potential (p = 0.04). Some studies failed to pass the sensitive analysis, indicating the related analysis might be not so stable. A slight publication bias was observed in subgroup analysis of function scales, among three publication bias test. In conclusion, compared to physical therapy, local corticosteroid injection might have better treatment effects on carpal tunnel syndrome.

Integrated 2D multi-fin field-effect transistors.

Vertical semiconducting fins integrated with high-κ oxide dielectrics have been at the centre of the key device architecture that has promoted advanced transistor scaling during the last decades. Single-fin channels based on two-dimensional (2D) semiconductors are expected to offer unique advantages in achieving sub-1 nm fin-width and atomically flat interfaces, resulting in superior performance and potentially high-density integration. However, multi-fin structures integrated with high-κ dielectrics are commonly required to achieve higher electrical performance and integration density. Here we report a ledge-guided epitaxy strategy for growing high-density, mono-oriented 2D Bi2O2Se fin arrays that can be used to fabricate integrated 2D multi-fin field-effect transistors. Aligned substrate steps enabled precise control of both nucleation sites and orientation of 2D fin arrays. Multi-channel 2D fin field-effect transistors based on epitaxially integrated 2D Bi2O2Se/Bi2SeO5 fin-oxide heterostructures were fabricated, exhibiting an on/off current ratio greater than 106, high on-state current, low off-state current, and high durability. 2D multi-fin channel arrays integrated with high-κ oxide dielectrics offer a strategy to improve the device performance and integration density in ultrascaled 2D electronics.

Insulin Resistance Surrogates May Predict HTN-HUA in Young, Non-Obese Individuals.

Objective: To compare the associations of three surrogate markers of insulin resistance (IR) [glucose and triglycerides (TyG index), TyG index with BMI (TyG-BMI), and the ratio of triglycerides divided by HDL-C (TG/HDL-C)] with hypertensive patients (HTN) plus hyperuricemia (HUA) (HTN-HUA) in young, non-obese individuals. Methods: Data from a cross-sectional epidemiological study of an annual health check-up population aged younger than 66 years were used to calculate the three IR surrogate indexes. The association with HTN-HUA and insulin resistance surrogates was examined with multinomial logistic regression and a receiver operating characteristic (ROC) curve. Results: A total of 6952 participants were included, including 671 (9.65%) participants with HTN alone, 272 (3.91%) participants with HUA alone, and 62 (0.90%) participants with HTN and HUA. Binary multiple-logistic regression results showed that TG/HDL-C was significantly correlated with HTN, HUA, and HTN-HUA. Compared with the lowest quartile, the odds ratios (95% CI) of the highest quartile of TG/HDL-C for HTN-HUA were 3.462 (1.138~10.530). TG/HDL-C and TyG-BMI had moderate discriminative abilities for HTN-HUA, and the area under the curve was 0.748 (0.682~0.815), 0.746 (0.694~0.798). Conclusion: Our study suggests that TG/HDL-C had a significant correlation with HTN-HUA and that TG/HDL-C had moderate discriminative abilities for HTN-HUA.

Probing charge redistribution at the interface of self-assembled cyclo-P5 pentamers on Ag(111).

Phosphorus pentamers (cyclo-P5) are unstable in nature but can be synthesized at the Ag(111) surface. Unlike monolayer black phosphorous, little is known about their electronic properties when in contact with metal electrodes, although this is crucial for future applications. Here, we characterize the atomic structure of cyclo-P5 assembled on Ag(111) using atomic force microscopy with functionalized tips and density functional theory. Combining force and tunneling spectroscopy, we find that a strong charge transfer induces an inward dipole moment at the cyclo-P5/Ag interface as well as the formation of an interface state. We probe the image potential states by field-effect resonant tunneling and quantify the increase of the local change of work function of 0.46 eV at the cyclo-P5 assembly. Our experimental approach suggest that the cyclo-P5/Ag interface has the characteristic ingredients of a p-type semiconductor-metal Schottky junction with potential applications in field-effect transistors, diodes, or solar cells.

Hinokiflavone from Platycladi cacumen as a potent broad-spectrum inhibitor of gut microbial Loop-1 ß-glucuronidases: Inhibition kinetics and molecular simulation.

Gut microbial Loop-1 ß-glucuronidases (gmGUS) played an important role in irinotecan-induced gastrointestinal toxicity by regulating the level of its active metabolite SN38 through enterohepatic recirculation. gmGUS inhibition has emerged as a promising approach to relieve its dose-limiting intestinal toxicity and improve its medication efficacy. This study aims to investigate the inhibitory effects and mechanisms of Platycladi cacumen and its main constituent hinokiflavone against four different types of Loop-1 gmGUS (EeGUS, SaGUS, CpGUS and EcGUS). Our results showed that the ethanol extract of Platycladi cacumen displayed strong broad-spectrum inhibition against four gmGUS, and hinokiflavone could potently inhibit EeGUS, SaGUS, CpGUS and EcGUS with IC50 values of 0.09 ± 0.01 µM, 0.44 ± 0.01 µM, 0.20 ± 0.01 µM and 0.69 ± 0.10 µM, respectively. Inhibition kinetic analyses demonstrated that hinokiflavone acted as a strong competitive inhibitor of EeGUS with Ki value of 0.13 µM, while it displayed non-competitive inhibition against SaGUS, CpGUS and EcGUS, with the Ki values of 0.43 µM, 0.33 µM and 0.76 µM, respectively. Docking simulations revealed that hinokiflavone could tightly bind with Tyr-485 and Glu-516 in catalytic sites of EeGUS, as well it created strong interactions with amino acids in loop structures of SaGUS (Asn-362), CpGUS (Phe-363, Met-364, Ala-365 and Arg-375) and EcGUS (Leu-361) to interfere the substrate entry into the catalytic pocket. Collectively, these results confirmed that hinokiflavone from Platycladi cacumen is a potent naturally occurring inhibitor of gmGUS with broad efficiency, suggesting hinokiflavone will be helpful for alleviating intestinal toxicity in irinotecan therapy.

Structural basis for recognition of 26RFa by the pyroglutamylated RFamide peptide receptor.

The neuropeptide 26RFa, a member of the RF-amide peptide family, activates the pyroglutamylated RF-amide peptide receptor (QRFPR), a class A GPCR. The 26RFa/QRFPR system plays critical roles in energy homeostasis, making QRFPR an attractive drug target for treating obesity, diabetes, and eating disorders. However, the lack of structural information has hindered our understanding of the peptide recognition and regulatory mechanism of QRFPR, impeding drug design efforts. In this study, we determined the cryo-EM structure of the Gq-coupled QRFPR bound to 26RFa. The structure reveals a unique assembly mode of the extracellular region of the receptor and the N-terminus of the peptide, and elucidates the recognition mechanism of the C-terminal heptapeptide of 26RFa by the transmembrane binding pocket of QRFPR. The study also clarifies the similarities and distinctions in the binding pattern of the RF-amide moiety in five RF-amide peptides and the RY-amide segment in neuropeptide Y. These findings deepen our understanding of the RF-amide peptide recognition, aiding in the rational design of drugs targeting QRFPR and other RF-amide peptide receptors.