Transient oxytocin signaling primes the development and function of excitatory hippocampal neurons

Beyond its role in parturition and lactation, oxytocin influences higher brain processes that control social behavior of mammals, and perturbed oxytocin signaling has been linked to the pathogenesis of several psychiatric disorders. However, it is still largely unknown how oxytocin exactly regulates neuronal function. We show that early, transient oxytocin exposure in vitro inhibits the development of hippocampal glutamatergic neurons, leading to reduced dendrite complexity, synapse density, and excitatory transmission, while sparing GABAergic neurons. Conversely, genetic elimination of oxytocin receptors increases the expression of protein components of excitatory synapses and excitatory synaptic transmission in vitro. In vivo, oxytocin-receptor-deficient hippocampal pyramidal neurons develop more complex dendrites, which leads to increased spine number and reduced γ-oscillations. These results indicate that oxytocin controls the development of hippocampal excitatory neurons and contributes to the maintenance of a physiological excitation/inhibition balance, whose disruption can cause neurobehavioral disturbances.

DOI:http://dx.doi.org/10.7554/eLife.22466.001

Abstract OT1-03-18: COLET: A multistage, phase 2 study evaluating the safety and efficacy of cobimetinib in combination with paclitaxel as first-line treatment for patients with metastatic triple-negative breast cancer

Background: Cobimetinib (cobi) is a potent, highly selective inhibitor of MEK that has shown benefit when administered in combination with the BRAF inhibitor vemurafenib in BRAFV600-mutated metastatic melanoma. Preclinical data suggest that up-regulation of the MAPK pathway is a potential resistance mechanism against taxane chemotherapy. Clinically, the combination of MEK inhibition and taxane chemotherapy in non–small cell lung cancer patients (pts) has improved response rate (RR) and progression-free survival (PFS). Because most triple-negative breast cancer (TNBC) pts develop resistance to taxane chemotherapy and because genetic alterations (including mutations and gene amplifications) in the MAPK pathway are present in many TNBC tumors, the combination of taxane chemotherapy and MEK inhibition could be an effective treatment option.

Study design: COLET (WO29497) is a multistage study designed to evaluate the safety of and to estimate the efficacy of cobi  paclitaxel in pts with metastatic or locally advanced TNBC who have not previously received systemic therapy for metastatic disease. The study will be conducted in 2 stages: an initial safety run-in stage of approximately 12 pts, followed by a randomized stage in which approximately 100 pts will be randomly assigned in a 1:1 ratio to receive either cobi + paclitaxel or placebo + paclitaxel. Pts will receive paclitaxel 80 mg/m2 on Days 1, 8, and 15 of each 28-day cycle and cobi/placebo 60 mg/day on Days 3-23 of each 28-day cycle until progression of disease or toxicity occurs.

Key eligibility criteria:

• Metastatic or locally advanced (not amenable to curative resection) TNBC

• No prior systemic therapy for metastatic or unresectable locally advanced TNBC

• Neoadjuvant or adjuvant chemotherapy or radiation therapy is allowed if completed >6 months before the start of study treatment

• Measureable disease using Response Evaluation Criteria In Solid Tumors, version 1.1 (RECIST v1.1)

• History of or active untreated or unstable brain metastases or requiring corticosteroids for brain metastases precludes eligibility

• Left ventricular ejection fraction (LVEF) greater than the institutional lower limit of normal or above 50%

Specific aims of the safety run-in stage: Determine the safety and tolerability of cobi when administered in combination with paclitaxel.

Specific aims of the randomized stage: Investigator-assessed PFS (primary end point); safety; pharmacokinetics; the effect of intrinsic subtypes and genetic alterations in PFS; mechanisms of resistance; and health-related quality of life.

Accrual: Approximately 112 pts from sites across Europe, North America, and the Asia-Pacific region.

Statistical methods: In the randomized stage, pts will be followed up until a total of 60 PFS events occur across the 2 arms. This provides 77% power to detect a hazard ratio of 0.5 at a two-sided significance level of 0.05.

Contact information: Registered with ClinicalTrials.gov, identifier NCT02322814. For more information, please contact Roche/Genentech trials, 888-662-6728 (US only) or reference study ID WO29479 at www.roche.com/about_roche/roche_worldwide.htm.

Citation Format: Kim S-B, Miles D, Rhee J, Yan Y, Hsu J, Brufsky A. COLET: A multistage, phase 2 study evaluating the safety and efficacy of cobimetinib in combination with paclitaxel as first-line treatment for patients with metastatic triple-negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT1-03-18.

A Spanish version of the Skin Cancer Index: a questionnaire for measuring quality of life in patients with cervicofacial nonmelanoma skin cancer

INTRODUCTION

The Skin Cancer Index (SCI) is the first specific patient-reported outcome measure for patients with cervicofacial nonmelanoma skin cancer. To date, only the original English version has been published.

OBJECTIVES

To develop a Spanish version of the SCI that is semantically and linguistically equivalent to the original, and to evaluate its measurement properties in this different cultural environment.

MATERIAL AND METHODS

A cross-sectional study was conducted of the cultural adaptation and empirical validation of the questionnaire, analysing the psychometric properties of the new index at different stages.

RESULTS

Of 440 patients recruited to the study, 431 (95%) completed the Spanish version of the SCI questionnaire, in a mean time of 6·3 min (SD 2·9). Factor analysis of the scale revealed commonality and loading values of < 0·5 for three of the 15 items. The remaining 12 items converged into two components: appearance/social aspects (seven items) and emotional aspects (five items). Both domains presented a high level of internal consistency, with Cronbach's alpha values above 0·8. The convergent-discriminant validity analysis produced correlations higher than 0·3 for the mental component of the Short Form Health Survey-12v2 Health Questionnaire (correlation coefficient 0·39) and the Dermatology Quality of Life Index (correlation coefficient -0·30). In the test-retest, nine of the 12 items produced a weighted kappa value exceeding 0·4, and for the remaining three items, the absolute agreement percentage exceeded 60%.

CONCLUSIONS

The Spanish version of the SCI quality of life scale has been satisfactorily adapted and validated for use in Spanish-speaking countries and populations.

Secretory vesicle priming by CAPS is independent of its SNARE-binding MUN domain

Priming of secretory vesicles is a prerequisite for their Ca(2+)-dependent fusion with the plasma membrane. The key vesicle priming proteins, Munc13s and CAPSs, are thought to mediate vesicle priming by regulating the conformation of the t-SNARE syntaxin, thereby facilitating SNARE complex assembly. Munc13s execute their priming function through their MUN domain. Given that the MUN domain of Ca(2+)-dependent activator protein for secretion (CAPS) also binds syntaxin, it was assumed that CAPSs prime vesicles through the same mechanism as Munc13s. We studied naturally occurring splice variants of CAPS2 in CAPS1/CAPS2-deficient cells and found that CAPS2 primes vesicles independently of its MUN domain. Instead, the pleckstrin homology domain of CAPS2 seemingly is essential for its priming function. Our findings indicate a priming mode for secretory vesicles. This process apparently requires membrane phospholipids, does not involve the binding or direct conformational regulation of syntaxin by MUN domains of CAPSs, and is therefore not redundant with Munc13 action.

The morphological and molecular nature of synaptic vesicle priming at presynaptic active zones

Synaptic vesicle docking, priming, and fusion at active zones are orchestrated by a complex molecular machinery. We employed hippocampal organotypic slice cultures from mice lacking key presynaptic proteins, cryofixation, and three-dimensional electron tomography to study the mechanism of synaptic vesicle docking in the same experimental setting, with high precision, and in a near-native state. We dissected previously indistinguishable, sequential steps in synaptic vesicle active zone recruitment (tethering) and membrane attachment (docking) and found that vesicle docking requires Munc13/CAPS family priming proteins and all three neuronal SNAREs, but not Synaptotagmin-1 or Complexins. Our data indicate that membrane-attached vesicles comprise the readily releasable pool of fusion-competent vesicles and that synaptic vesicle docking, priming, and trans-SNARE complex assembly are the respective morphological, functional, and molecular manifestations of the same process, which operates downstream of vesicle tethering by active zone components.

Demographic and serological characteristics of Asian Americans with hepatitis B infection diagnosed at community screenings

There is limited information regarding follow-up and hepatitis B serological status of Asian Americans diagnosed with chronic hepatitis B (CHB) through community screening. The aims of this study were to evaluate the prevalence and characterize CHB among Asians living in Los Angeles, assess follow-up of individuals with CHB diagnosed at screening and compare with patients with CHB followed by community gastroenterologists. Between October 2007 and May 2010, 7387 Asians were tested for HBV. HBsAg positive individuals (CHB) underwent additional testing for ALT, HBeAg/anti-HBe and HBV DNA. Patients with CHB were contacted 6 months later to determine whether they received follow-up care. We compared serological patterns of these individuals with CHB to patients with CHB who were seen for the first time (treatment naïve) by community gastroenterologists during the study period. Prevalence of CHB was 5.2%. About 99% patients with CHB were foreign-born, and only 27% could read/write English. 297 (77%) patients with CHB could be reached 6 months after diagnosis; 43% did not receive follow-up care, mostly because of lack of medical insurance. Patients with CHB followed by gastroenterologists were more likely to have insurance (69% vs 26%, P < 0.0001). 90% patients with CHB at screening were HBeAg negative/anti-HBe positive with 62% having inactive disease compared to only 30% of patients seen by gastroenterologists (P < 0.0001). Among CHB participants, 13% met criteria for treatment compared to 51% of patients with CHB (P < 0.0001). Only a small number of CHB screening participants require antiviral therapy. Lack of medical insurance is the main reason for most patients with CHB not seeking follow-up care after screening.

Neurobeachin regulates neurotransmitter receptor trafficking to synapses

The surface density of neurotransmitter receptors at synapses is a key determinant of synaptic efficacy. Synaptic receptor accumulation is regulated by the transport, postsynaptic anchoring, and turnover of receptors, involving multiple trafficking, sorting, motor, and scaffold proteins. We found that neurons lacking the BEACH (beige-Chediak/Higashi) domain protein Neurobeachin (Nbea) had strongly reduced synaptic responses caused by a reduction in surface levels of glutamate and GABA(A) receptors. In the absence of Nbea, immature AMPA receptors accumulated early in the biosynthetic pathway, and mature N-methyl-d-aspartate, kainate, and GABA(A) receptors did not reach the synapse, whereas maturation and surface expression of other membrane proteins, synapse formation, and presynaptic function were unaffected. These data show that Nbea regulates synaptic transmission under basal conditions by targeting neurotransmitter receptors to synapses.

OS094. Subclinical left ventricular dysfunction in preeclamptic women with preserved left ventricular ejection fraction: A 2D speckle tracking imaging study

INTRODUCTION

Patients with preeclampsia are at risk for cardiovascular disease [1,2]. Changes in cardiac function are subtle in preeclampsia and are quantitatively difficult with conventional imaging. Strain measurements using speckle-tracking echocardiography have been used to sensitively quantifyabnormalities in other disease settings [3].

OBJECTIVES

The objective of this study was to evaluate changes in myocardial strain using speckle tracking echocardiography in women with and without preeclampsia. We hypothesized that global left systolic strain measures would prove more sensitive than conventional left ventricular ejection fraction in detecting early changes in systolic LV function manifesting as subclinical disease prior to overt progression.

METHODS

We evaluated the feasibility and sensitivity of strain imaging using speckle tracking echocardiography. Thirty-six women were enrolled in this pilot study; 28 were analyzed: 11 with preeclampsia and 17 without preeclampsia. Echocardiographic Ejection fraction and global peak longitudinal ,radial and circumferential strain were measured.

RESULTS

Global Median longitudinal strain was significantly worsened in women with preeclampsia compared to women without preeclampsia (P<0.0001). Similar results were observed for global radial strain (P=0.006) and circumferential strain (P=0.03). There was no significant difference in ejection fraction between the groups (P=0.52) (Table 1). Data are presented as median (interquartile range).

CONCLUSION

Myocardial strain imaging using speckle tracking is more sensitive than left ventricular ejection fraction to detect differences in left ventricular systolic function in women with and without preeclampsia.

Endoscopic versus direct vision for saphenous vein graft harvesting in coronary artery bypass surgery

AIM

Recent reports have suggested harvesting of the greater saphenous vein for coronary artery bypass (CABG) using endoscopic techniques (endoscopic) results in early graft closure, higher rates of myocardial infarction (MI) and death. We explored the impact of this technique performed by experienced operators on postoperative morbidities, MI and death in our CABG patients.

METHODS

All non-emergent patients presenting for first time CABG surgery from 2006 to June 2009 were included. Data pertaining to surgery, readmissions, cardiac catheterization and interventions during long term follow-up were extracted from our local STS and ACC registries. Linear and logistic regressions with clinical covariates were conducted to determine if vein harvest technique group predicted the major outcomes. Propensity score matching (PSM) was completed to simulate randomization and improve covariate balance across the endoscopic and direct vision groups.

RESULTS

One thousand nine hundred and eighty-eight (N.=1988) patients were evaluated in this study (N.=1734 endoscopic group and N.=254 direct vision group). The perioperative major adverse outcomes (mortality within 30 days, stroke, reoperation for bleeding, prolonged ventilation and readmission within 30 days) were 17.8% in the endoscopic group and 25.2% in the direct vision group. The rate of leg infections was 0.3% for the endoscopic group and 1.6% for the direct vision group. After adjustment for covariates, the direct vision group had significantly greater risk for prolonged ventilation (P=0.03), MACE (P=0.02) and mortality within 30 days (P=0.01), but only marginally greater risk for leg infections (P=0.052). In the isolated CABG patients, operative death was 1% for the endoscopic group and 1.7% in the direct vision group (P=0.62). After PSM the endoscopic group was similar on all outcomes except for having fewer MACE (P=0.04). In a mean follow-up of 22.1±10.5 months, there were no significant differences in the overall rate and time to event for repeat revascularization, death and myocardial infarction. With maximum follow up of 39.6 months, 84 deaths were documented (N.=67 endoscopic and N.=17 direct vision).

CONCLUSION

The outcomes captured by the number of postoperative morbidities, incidence of myocardial infarction and/or the rate of death for the endoscopic technique were comparable to patients in whom the open techniques was used. There was a trend towards a decrease in leg infections with the use of the endoscopic device. Based on this study we consider the device safe and effective with experienced operators.

CYP2A6 and ERCC1 polymorphisms correlate with efficacy of S-1 plus cisplatin in metastatic gastric cancer patients

Background:

We evaluated the association between polymorphisms of cytochrome P450 2A6 (CYP2A6)/excision repair cross-complementation group 1 (ERCC1)/X-ray repair cross-complementing group 1(XRCC1) and treatment outcomes of metastatic gastric cancer (MGC) patients treated with S-1/cisplatin.

Methods:

Among MGC patients (n=108), who received S-1 (40 mg m⁻² b.i.d., days 1–14) and cisplatin (60 mg m⁻², day 1) every 3 weeks, we analysed the wild-type allele (W) and variants (V) of CYP2A6 (*4, *7, *9, *10), and the polymorphisms of ERCC1 (rs11615, rs3212986) and XRCC1 (rs25487).

Results:

Patients having fewer CYP2A6 variants had better response rates (W/W vs W/V other than *1/*4 vs V/V or *1/*4=66.7 vs 58.3 vs 32.3% P=0.008), time to progression (TTP) (7.2 vs 6.1 vs 3.5 months, P=0.021), and overall survival (23.2 vs 15.4 vs 12.0 months, P=0.004). ERCC1 19442C>A (rs3212986) was also associated with response rate (C/C, 46.7% vs C/A, 55.3% vs A/A, 87.5%) (P=0.048) and TTP (4.4 vs 7.6 vs 7.9 months) (P=0.012). Patients carrying both risk genotypes of CYP2A6 (V/V or 1/*4) and ERCC1 19442C>A (C/C) vs those carrying none showed an adjusted odds ratio of 0.113 (P=0.004) for response, and adjusted hazard ratios of 3.748 (P=0.0001) for TTP and 2.961 (P=0.006) for death.

Conclusion:

Polymorphisms of CYP2A6 and ERCC1 19442C>A correlated with the efficacy of S-1/cisplatin.

Two distinct secretory vesicle-priming steps in adrenal chromaffin cells

The calcium-dependent activator proteins for secretion, CAPS1 and CAPS2, facilitate syntaxin opening during synaptic vesicle priming.

Priming of large dense-core vesicles (LDCVs) is a Ca²⁺-dependent step by which LDCVs enter a release-ready pool, involving the formation of the soluble N-ethyl-maleimide sensitive fusion protein attachment protein (SNAP) receptor complex consisting of syntaxin, SNAP-25, and synaptobrevin. Using mice lacking both isoforms of the calcium-dependent activator protein for secretion (CAPS), we show that LDCV priming in adrenal chromaffin cells entails two distinct steps. CAPS is required for priming of the readily releasable LDCV pool and sustained secretion in the continued presence of high Ca²⁺ concentrations. Either CAPS1 or CAPS2 can rescue secretion in cells lacking both CAPS isoforms. Furthermore, the deficit in the readily releasable LDCV pool resulting from CAPS deletion is reversed by a constitutively open form of syntaxin but not by Munc13-1, a priming protein that facilitates the conversion of syntaxin to the open conformation. Our data indicate that CAPS functions downstream of Munc13s but also interacts functionally with Munc13s in the LDCV-priming process.