5-IP7 is a GPCR messenger mediating neural control of synaptotagmin-dependent insulin exocytosis and glucose homeostasis

5-diphosphoinositol pentakisphosphate (5-IP₇) is a signalling metabolite linked to various cellular processes. How extracellular stimuli elicit 5-IP₇ signalling remains unclear. Here we show that 5-IP₇ in β cells mediates parasympathetic stimulation of synaptotagmin-7 (Syt7)-dependent insulin release. Mechanistically, vagal stimulation and activation of muscarinic acetylcholine receptors triggers G_αq-PLC-PKC-PKD-dependent signalling and activates IP6K1, the 5-IP₇ synthase. Whereas both 5-IP₇ and its precursor IP₆ compete with PIP₂ for binding to Syt7, Ca²⁺ selectively binds 5-IP₇ with high affinity, freeing Syt7 to enable fusion of insulin-containing vesicles with the cell membrane. β-cell-specific IP6K1 deletion diminishes insulin secretion and glucose clearance elicited by muscarinic stimulation, whereas mice carrying a phosphorylation-mimicking, hyperactive IP6K1 mutant display augmented insulin release, congenital hyperinsulinaemia and obesity. These phenotypes are absent in mice lacking Syt7. Our study proposes a new conceptual framework for inositol pyrophosphate physiology in which 5-IP₇ acts as a GPCR second messenger at the interface between peripheral nervous system and metabolic organs, transmitting G_q-coupled GPCR stimulation to unclamp Syt7-dependent, and perhaps other, exocytotic events.

Cross-genera amplification and identification of Colpodella sp. with Cryptosporidium primers in fecal samples of zoo felids from northeast China

The protozoans include many intracellular human pathogens. Accurate detection of these pathogens is necessary to treat the diseases. In clinical epidemiology, molecular identification of protozoan is considered a more reliable and rapid method for identification than microscopy. Among these protozoans, Cryptosporidium considered being one of the important water-borne zoonotic pathogens and a major cause of a diarrheal disease named cryptosporidiosis in humans, domestic animals, and wild animals. This study was aimed to identify Cryptosporidium in zoo felids (N= 56) belonging to different zoo of China, but accidentlly Colpodella was encountered in the zoo felids sample and phylogenetic data confirmed this unexpected amplification from fecal samples using two-step nested-PCR. Phylogenetic analysis revealed the fact about the specific primers used previously by many researchers and cross-genera amplification. We came to know that genetically sequenced amplicon gives more accurate identification of species. This study suggests more investigation on Colpodella which has been neglected previously but gains the attention of researchers after identified from humans and animals and has been known to correlate with neurological symptoms in patients.

Impact of age and menopausal stage on serum anti-Müllerian hormone levels in middle-aged women

OBJECTIVE

This study aimed to evaluate the association between age, menopausal stage and serum anti-Müllerian hormone (AMH) levels in middle-aged women.

METHODS

In this cross-sectional study, the serum AMH levels of 288 healthy women aged 40-55 years (divided into age groups: 40-44, 45-49 and 50-55 years) were evaluated. Stages of Reproductive Aging Workshop + 10 criteria were used to categorize these women into menopausal stages: late reproductive, menopausal transition and early postmenopausal stages. The impact of age, menopausal stage and hormone replacement therapy on serum AMH levels was analyzed using multi-factor analysis of variance. Effects of body mass index, smoking status and oral contraceptive use were simultaneously considered.

RESULTS

The median AMH level was 0.140 ng/ml. Log-AMH levels varied according to age group (variance = 20.113, F = 88.538, p < 0.001) and menopausal stage (variance = 5.543, F = 24.501, p < 0.001). An exponential model defined as AMH = 227,421.757 × e^{(-0.301 × age)} was fit to describe the decline in AMH level with age. The 5th-95th percentiles of the AMH levels ranged from less than 0.020 to 3.150, less than 0.020 to 1.944 and less than 0.020 to 0.030 ng/ml in the aforementioned menopausal stages, respectively.

CONCLUSION

Age and menopausal stage were associated with AMH levels; age had a greater impact on AMH than menopausal stage in middle-aged women.

Traumatic fractures in China from 2012 to 2014: a National Survey of 512,187 individuals

The China National Fracture Study has been conducted to provide a national dataset of traumatic fractures across China. A national representative sample of 512,187 individuals was selected. The population-weighted incidence rates, distribution, injury mechanisms, and risk factors for traumatic fractures were identified for various groups of individuals.

INTRODUCTION

The China National Fracture Study (CNFS) has been conducted to provide a comprehensive and up-to-date national dataset of traumatic fractures across China. This study aims to report the national incidences and distributions of traumatic fractures that occurred in 2012, 2013, and 2014 and to analyze the risk factors.

METHODS

A national representative sample of individuals was selected from 24 rural counties and 24 urban cities of 8 provinces using stratified random sampling and the probability proportional to size (PPS) methodology. Participants were interviewed to identify whether they sustained traumatic fractures of the trunk and/or four extremities that had occurred in 2012, 2013, and 2014. The main risk factors associated with traumatic fractures were analyzed by multiple logistic regression models.

RESULTS

A total of 512,187 individuals, including 259,649 males and 252,538 females, participated in the CNFS. The population-weighted incidence rates of traumatic fractures in China were calculated to be 2.5 (95% CI, 2.2-2.8) per 1000 population in 2012, 2.8 (95% CI, 2.5-3.3) in 2013, and 3.2% (95% CI, 2.8-3.6) in 2014. The population-weighted incidence rates of fragility fractures among participants aged 65 years and older were calculated to be 27.4 (95% CI, 21.4-33.4) per 1000 population in 2012, 36.0 (95% CI, 28.6-43.5) in 2013, and 42.4 (95% CI, 34.9-49.9) in 2014. The most common cause of fracture was low-energy injuries, followed by traffic accidents. For all age groups, sleeping less than 7 h was a risk factor for traumatic fractures. Alcohol consumption and previous fracture history were identified as risk factors for adults aged 15 years and over. Cigarette smoking was found to be a risk factor for males aged 15-64 years old. For individuals aged 15-64 years old, underweight incurred a risk effect for males and overweight for females. Alcohol consumption, sleeping less than 7 h per day, living in the central and eastern regions, a body mass index less of than 18.5, and having a previous fracture history were identified as strong risk factors for fragility fractures.

CONCLUSION

The national incidence, distribution, and injury mechanisms for traumatic fractures were revealed in the CNFS. Risk factors were identified for various groups of individuals.

CDC6 is up-regulated and a poor prognostic signature in glioblastoma multiforme

PURPOSE

Glioblastoma multiforme (GBM) represents the most common and the most malignant type of brain tumor. Cell division cycle 6 (CDC6), a gene associated with DNA replication initiation, has been proven to be associated with the prognosis of multiple tumors. In this study, we aim to explore the association between CDC6 expression and GBM carcinogenesis and prognosis.

METHODS

CDC6 expression in normal cells and GBM cells was explored by analyzing TCGA dataset, as well as by RT-PCR and western blot methods. Survival analysis was performed by the Kaplan-Meier method. Multivariate Cox-regression analysis was adopted to estimate the independence of CDC6 as a GBM prognostic factor.

RESULTS AND CONCLUSIONS

Elevated CDC6 levels in GBM tumor tissues compared with those in normal brain tissues were illustrated by analyzing the gene expression profiles from TCGA dataset, and confirmed by RT-PCR and western blot assays in GBM tumor and normal human astrocyte cell lines. Kaplan-Meier analysis indicated the negative influence of high CDC6 expression on GBM overall survival (OS) probability and days to progression (D2P) after initial treatment, but not on days to recurrence (D2R) after initial treatment. Multivariate Cox regression analysis showed CDC6 as an independent signature marker gene for GBM prognosis. In addition, the combination of CDC6 mRNA expression and CpG island methylator phenotype (CIMP) could sensitively predict 3-year OS and D2P. In conclusion, our study uncovered the role of CDC6 in GBM carcinogenesis and prognosis for the first time, which could shed new light on GBM diagnosis and treatment.

Intramolecular methionine alkylation constructs sulfonium tethered peptides for protein conjugation

Continuous efforts have been invested in the selective modification of proteins.

Expression of C1q/TNF-related protein-3 (CTRP3) in serum of patients with gestational diabetes mellitus and its relationship with insulin resistance

OBJECTIVE

In this study, the changes of insulin resistance (IR) and pancreatic β-cell function in GDM patients were observed, changes of CTRP3 level in fasting serum and relationships with plasma glucose (PG) and pancreatic β-cell function were explored at the same time, and the correlation between serum CTRP3 and body mass index (BMI) was preliminarily discussed, providing a new way to identify the pathogenesis of GDM.

PATIENTS AND METHODS

Data of women from 24 to 28 weeks of pregnancy were collected. 100 women were selected to form gestational diabetes mellitus (GDM) group and another 100 women were chosen to constitute normal glucose tolerance (NGT) group according to the results of oral glucose tolerance test (OGTT). They were divided into GDM overweight/obesity (GDM + OW) group, GDM non-overweight/obesity (GDM + NW) group, simple overweight (OW) group and normal body weight (NW) group, according to whether the progestational body mass index (BMI) was higher than 24 kg/m2 before pregnancy. General information of all subjects, for example, age, last menstrual period, parity, diet, weight and height, were collected, and blood samples were taken from all subjects for use in detections of total cholesterol (TC), triglyceride (TG), very low-density lipoprotein (VLDL), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and serum C1q/tumor necrosis factor-related protein-3 (CTRP3).

RESULTS

The levels of FPG, 1 h PG, 2 h PG, fasting CP (FCP), fasting insulin (FINS), homeostasis model assessment of IR (HOMA-IR), TG and VLDL-C in the GDM group, were significantly higher than those in the NGT group. TC and LDL-C in the GDM group were greater than those in the NGT group. Compared with that in the NGT group, homeostasis model assessment of β (HOMA-β) index was lower in the GDM group. From the NGT group to the GDM group, FPG, 1 h PG, 2 h PG, FINS and FCP had rising tendencies, and the differences were of statistical significance. Pearson correlation analysis indicated that HOMA-IR was positively correlated with pre-pregnancy BMI, FPG, 2 h PG, FINS, 1 h INS, 2 h INS, FCP, 1 h CP and 2 h CP in the GDM group, HOMA-β was negatively related to FPG. In the NGT group, there was a positive correlation between HOMA-IR and pre-pregnancy BMI. The level of CTRP3 in fasting serum of the GDM group was distinctly lower than that of the NGT group. Pearson correlation analysis revealed that in the GDM group, fasting serum CTRP3 had positive correlations with HOMA-β and HDL-C, but negatively associated with pre-pregnancy BMI, FPG, 1 h PG, 2 h PG, FCP, HOMA-IR, TG and VLDL-C. In the NGT group, the fasting serum CTRP3 was negatively correlated with pre-pregnancy BMI. Multiple linear stepwise regression analysis showed FPG was an independent influencing factor for fasting serum CTRP3.

CONCLUSIONS

With the increase of FPG, the progression of GDM IR patients is increased, and pancreatic β-cell function progressively declines. The decrease of CTRP3 level in fasting serum in GDM patients plays a metabolic role in the pathogenesis of GDM.

Genetic variation and phylogenetic analysis of Porcine circovirus type 2 in China from 2016 to 2018

Infection with Porcine circovirus type 2 (PCV2), the essential cause of porcine circovirus (PCV) associated diseases, is a growing problem in swine industry around the world. High nucleotide alteration leads to the constant evolution of PCV2 and outbreak of disease caused by PCV2. In this study, 48 PCV2 strains were isolated in China between 2016 and 2018 and the genetic diversity of these PCV2 isolates was determined. Results showed that these PCV2 isolates were classified into genotypes PCV2a (4 of 48), PCV2b (13 of 48) and PCV2d (31 of 48). Among them, 54.5% isolated in 2016, 65.2% isolated in 2017 and 71.4% isolated in 2018 belonged to PCV2d. It indicated that the prevalence of PCV2d genotype increased. All strains shared 93.4%-100% nucleotide sequence identity for the whole genome. Results of the analysis using RDP 4.0 molecular recombination software showed there were no recombinant events among the 48 PCV2 isolates in this study. Further analysis indicated the presence of higher amino acid residues diversity in important epitopes (43D/G, 115D/G, 134N/T, 165P/T, 169G/R/S, and 210E/G/D) in the predominant genotype PCV2d. Animal tests showed the viral titer of the PCV2d strain LN-3 in sera was higher than that of PCV2b strain HeB-1 at 14 and 21 days post-challenge, however, the differences were not statistically significant. There were also no obvious differences between PCV2d strain LN-3 and PCV2b strain HeB-1 in the amount of PCV2 antigen in lymphoid tissues. On the account of the increasing prevalence of PCV2d genotype, it is necessary to find the cause of PCV2 genotype change, to evaluate the effect of existing commercial vaccines and to develop new vaccines based on PCV2d genotype, if necessary. Keywords: epitope; PCV2d; phylogeny; Porcine circovirus type 2; recombination; genetic diversity.

α-Helical Motif as Inhibitors of Toxic Amyloid-β Oligomer Generation via Highly Specific Recognition of Amyloid Surface

Amyloid fibril surfaces can convert soluble proteins into toxic oligomers and are attractive targets for intervention of protein aggregation diseases. Thus far, molecules identified with inhibitory activity are either large proteins or flat cyclic compounds lacking in specificity. The main design difficulty is flatness of amyloid surfaces and the lack of knowledge on binding interfaces. Here, we demonstrate, for the first time, a rational design of alpha-helical peptide inhibitors targeting the amyloid-beta 40 (Aβ40) fibril surfaces, based on our in silico finding that a helical fragment of Aβ40 interacts in a unique way with side-chain arrays on the fibril surface. We strengthen the fragment's binding capability through mutations and helicity enhancement with our Terminal Aspartic acid strategy. The resulting inhibitor shows micromolar affinity for the fibril surface, effectively impedes the surface-mediated oligomerization of Aβ40, and mitigates its cytotoxicity. This work opens up an avenue to designing aggregation modulators for amyloid diseases.

[Derepression of CXCR7 indicates resistance to enzalutamide in castration resistant prostate cancer]

Objective: To investigate the effect of the derepression of chemokine receptor-7 (CXCR7) in prostatic tissues from patients with Castration Resistant Prostate Cancer (CRPC) on the resistance to enzalutamide (Enza). Methods: During the period of January 2015 to December 2017 all CRPC cases who underwent radical radiotherapy or androgen deprivation therapy (ADT) were evaluated. After prostatic puncture biopsy, the tissues were treated for immunostaining with CXCR7. Cox proportional hazard modeling and Kaplan-Meier analysis were used to determine PSA Progression-Free Survival (PSAP-FS) and Clinical or Radiographic Progression-Free Survival (CRP-FS) in the cohort. At last, PSA response rates and progression outcomes in CXCR7 negative cases and CXCR7 positive cases were analyzed. Results: Total 39 CRPC patients were enrolled in this study. And 23 cases derepress CXCR7, 16 cases negatively express CXCR7. The median follow-up duration was 12 months (range: 6-18) in the cohort. Chi-square analysis confirmed that PSA response rates after Enza treatment were significantly associated with CXCR7 derepression (χ(2)=22.129, P=0.000 06). Compared with CXCR7 positive expression group, CXCR7 negative expression group displayed improved median PSAP-FS (4.4 mon vs 11.7 mon, P=0.040 8) and CRP-FS (5.2 mon vs 13.1 mon, P=0.036 2) after Enza treatment. Conclusion: Derepression of CXCR7 in CRPC patients may be associated with resistance to enzalutamide. This protein may be novel target for treatment of CRPC.

A sulfonium tethered peptide ligand rapidly and selectively modifies protein cysteine in vicinity

Significant efforts have been invested to develop site-specific protein modification methodologies in the past two decades. In most cases, a reactive moiety was installed onto ligands with the sole purpose of reacting with specific residues in proteins. Herein, we report a unique peptide macrocyclization method via the bis-alkylation between methionine and cysteine to generate cyclic peptides with significantly enhanced stability and cellular uptake. Notably, when the cyclized peptide ligand selectively recognizes its protein target with a proximate cysteine, a rapid nucleophilic substitution could occur between the protein Cys and the sulfonium center on the peptide to form a conjugate. The conjugation reaction is rapid, facile and selective, triggered solely by proximity. The high target specificity is further proved in cell lysate and hints at its further application in activity based protein profiling. This method enhances the peptide's biophysical properties and generates a selective ligand-directed reactive site for protein modification and fulfills multiple purposes by one modification. This proof-of-concept study reveals its potential for further broad biological applications.

Facile Chemoselective Modification of Thio-Ethers Generates Chiral Center-Induced Helical Peptides

A precisely positioned sulfimide chiral center on-tether of a thio-ether tethered peptide determines the peptide secondary structure by chemoselective oxaziridine modification. This method provides a facile way to tune peptides' secondary structures and biophysical properties.

N terminal N-methylation modulates chiral centre induced helical (CIH) peptides’ biophysical properties

The effects of N-methylation on CIH peptides’ biophysical properties were systematically studied.

Role of proton-coupled folate transporter in pemetrexed resistance of mesothelioma: clinical evidence and new pharmacological tools

BACKGROUND

Thymidylate synthase (TS) has a predictive role in pemetrexed treatment of mesothelioma; however, additional chemoresistance mechanisms are poorly understood. Here, we explored the role of the reduced-folate carrier (RFC/SLC19A1) and proton-coupled folate transporter (PCFT/SLC46A1) in antifolate resistance in mesothelioma.

PATIENTS AND METHODS

PCFT, RFC and TS RNA and PCFT protein levels were determined by quantitative RT-PCR of frozen tissues and immunohistochemistry of tissue-microarrays, respectively, in two cohorts of pemetrexed-treated patients. Data were analyzed by t-test, Fisher's/log-rank test and Cox proportional models. The contribution of PCFT expression and PCFT-promoter methylation to pemetrexed activity were evaluated in mesothelioma cells and spheroids, through 5-aza-2'-deoxycytidine-mediated demethylation and siRNA-knockdown.

RESULTS

Pemetrexed-treated patients with low PCFT had significantly lower rates of disease control, and shorter overall survival (OS), in both the test (N = 73, 11.3 versus 20.1 months, P = 0.01) and validation (N = 51, 12.6 versus 30.3 months, P = 0.02) cohorts. Multivariate analysis confirmed PCFT-independent prognostic role. Low-PCFT protein levels were also associated with shorter OS. Patients with both low-PCFT and high-TS levels had the worst prognosis (OS, 5.5 months), whereas associations were neither found for RFC nor in pemetrexed-untreated patients. PCFT silencing reduced pemetrexed sensitivity, whereas 5-aza-2'-deoxycytidine overcame resistance.

CONCLUSIONS

These findings identify for the first time PCFT as a novel mesothelioma prognostic biomarker, prompting prospective trials for its validation. Moreover, preclinical data suggest that targeting PCFT-promoter methylation might eradicate pemetrexed-resistant cells characterized by low-PCFT expression.