Endothelin-1 inhibition improves the mBDNF/proBDNF ratio in endothelial cells and HT22 neurons under high glucose/palmitate growth conditions

Diabetes increases the risk and worsens the progression of cognitive impairment. The hippocampus is an important domain for learning and memory. We previously showed that endothelin-1 (ET-1) reduced diabetes-induced inflammation in hippocampal neurons, suggesting a neuroprotective effect. Given that neurons and endothelial cells within the neurovascular unit depend on each other for proper function, we investigated the effect of ET-1 on brain-derived neurotrophic factor (BDNF) synthesis, a key neurotrophin and prosurvival factor, in neuronal (HT22 hippocampal neurons) and brain microvascular endothelial (BMEC-5i) cells under normal and diabetes-mimicking (high glucose plus palmitate) conditions. Cells were treated with exogenous ET-1 or ET receptor antagonists including ET(B) receptor selective antagonist BQ788 (1 microM) or dual-receptor antagonist bosentan (10 microM). Mature (m)BDNF, proBDNF and caspase-3 levels were measured by Western blotting. Diabetic conditions reduced the prosurvival mBDNF/proBDNF ratio in both HT22 and BMEC-5i cells. Addition of exogenous ET-1 had no effect on the BDNF system in HT22 cells in diabetic conditions. Both HT22 and BMEC-5i cells had an increase in the mBDNF/proBDNF ratio when grown in diabetes-simulating conditions in the presence of endothelin receptor inhibition. These data suggest that blockade of ET-1 may provide neuroprotection to hippocampal cells through the modulation of the BDNF system.

Endothelin and diabetic complications: a brain-centric view

The global epidemic of diabetes is of significant concern. Diabetes associated vascular disease signifies the principal cause of morbidity and mortality in diabetic patients. It is also the most rapidly increasing risk factor for cognitive impairment, a silent disease that causes loss of creativity, productivity, and quality of life. Small vessel disease in the cerebral vasculature plays a major role in the pathogenesis of cognitive impairment in diabetes. Endothelin system, including endothelin-1 (ET-1) and the receptors (ET(A) and ET(B)), is a likely candidate that may be involved in many aspects of the diabetes cerebrovascular disease. In this review, we took a brain-centric approach and discussed the role of the ET system in cerebrovascular and cognitive dysfunction in diabetes.

Exploring the Needs of Adolescents With Sickle Cell Disease to Inform a Digital Self-Management and Transitional Care Program: Qualitative Study

BACKGROUND

Accessible self-management interventions are critical for adolescents with sickle cell disease to better cope with their disease, improve health outcomes and health-related quality of life, and promote successful transition to adult health care services. However, very few comprehensive self-management and transitional care programs have been developed and tested in this population. Internet and mobile phone technologies can improve accessibility and acceptability of interventions to promote disease self-management in adolescents with sickle cell disease.

OBJECTIVE

The aim of this study was to qualitatively explore the following from the perspectives of adolescents, parents, and their health care providers: (1) the impact of sickle cell disease on adolescents to identify challenges to their self-management and transitional care and (2) determine the essential components of a digital self-management and transitional care program as the first phase to inform its development.

METHODS

A qualitative descriptive design utilizing audio-recorded, semistructured interviews was used. Adolescents (n=19, aged 12-19 years) and parents (n=2) participated in individual interviews, and health care providers (n=17) participated in focus group discussions and were recruited from an urban tertiary care pediatric hospital. Audio-recorded data were transcribed verbatim and organized into categories inductively, reflecting emerging themes using simple content analysis.

RESULTS

Data were categorized into 4 major themes: (1) impact of sickle cell disease, (2) experiences and challenges of self-management, (3) recommendations for self-management and transitional care, and (4) perceptions about a digital self-management program. Themes included subcategories and the perspectives of adolescents, parents, and health care providers. Adolescents discussed more issues related to self-management, whereas health care providers and parents discussed issues related to transition to adult health services.

CONCLUSIONS

Adolescents, parents, and health care providers described the continued challenges youth with sickle cell disease face in terms of psychosocial impacts and stigmatization. Participants perceived a benefit to alleviating some of these challenges through a digital self-management tool. They recommended that an effective digital self-management program should provide appropriate sickle cell disease-related education; guidance on developing self-advocacy and communication skills; empower adolescents with information for planning for their future; provide options for social support; and be designed to be engaging for both adolescents and parents to use. A digital platform to deliver these elements is an accessible and acceptable way to address the self-management and transitional care needs of adolescents.

Abstract 1856: Combination of the novel ERK inhibitor AZD0364 with the MEK inhibitor selumetinib significantly enhances antitumor activity in KRAS mutant tumor models

The RAS/MAPK pathway is a major driver in oncogenesis and is dysregulated in approximately 30% of human cancers, primarily by mutations in BRAF or RAS genes. While BRAF and MEK inhibitors improve BRAF mutant melanoma patient outcomes, single-agent pathway inhibitors have demonstrated limited clinical benefit. Therefore, combined inhibition of multiple nodes within the RAS/MAPK pathway may be necessary to effectively suppress pathway signaling and achieve meaningful clinical benefit, specifically in patients with KRAS mutant tumors. AZD0364 is a potent and highly selective inhibitor of ERK1 and ERK2. AZD0364 exhibits high cellular potency against a direct substrate (e.g., inhibition of phosphorylation of p90RSK in BRAF mutant A375 cells, IC50 = 6 nM) and is highly (10/329 kinases tested are inhibited at >50% at 1 µM). In an unbiased cell proliferation screen of 750 tumor cell lines, >50% of cell lines that are sensitive to AZD0364 have RAS/MAPK pathway genetic alterations such as BRAF, NRAS or KRAS mutations. In a subset of KRAS mutant NSCLC cell lines, combined treatment of AZD0364 and selumetinib (AZD6244, ARRY-142886) is highly synergistic. This combination results in deeper and more durable suppression of the RAS/MAPK pathway that is not achievable with single-agent treatment, as assessed by phospho-p90RSK, change in transcriptional signatures and induction of apoptotic biomarkers. The AZD0364 and selumetinib combination also significantly suppresses RAS/MAPK pathway output and tumor growth in vivo to a greater extent than achievable with either agent given as a monotherapy. This combination is well tolerated in vivo and delivers 65% tumor regression in the NCI H358 KRAS mutant NSCLC xenograft model. This combination also results in significant tumor regressions in both A549 and HCT116 KRAS mutant xenografts. These data demonstrate that combined AZD0364 and selumetinib is well tolerated, effectively suppresses RAS/MAPK pathway signalling and delivers durable regressions in preclinical models. The combination of ERK and MEK inhibition represents a viable clinical approach to target KRAS mutant tumors.

Citation Format: Vikki Flemington, Iain Simpson, Jason Breed, Emma Davies, Francis Gibbons, Phillip Hopcroft, Nicola Lyndsay, Christopher Jones, Clifford Jones, David Robinson, Claire Rooney, Karen Roberts, Linda Sandin, Richard Ward, Pei Zhang, Elizabeth Pease. Combination of the novel ERK inhibitor AZD0364 with the MEK inhibitor selumetinib significantly enhances antitumor activity in KRAS mutant tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1856.

Diagnostic accuracy and yield of screening tests for atrial fibrillation in the family practice setting: a multicentre cohort study

BACKGROUND

Detection of undiagnosed or undertreated ("actionable") atrial fibrillation could increase the use of appropriate oral anticoagulant therapy and reduce the risk of stroke. We sought to compare newer screening technologies with a pulse-check for the detection of atrial fibrillation and to determine whether the detection of actionable atrial fibrillation increases the use of oral anticoagulant agents.

METHODS

This prospective multicentre cohort study involved 22 primary care clinics. We recruited participants aged 65 years and older who were attending routine appointments. Each participant underwent 3 methods of screening: a 30-second radial pulse-check; single-lead electrocardiogram; and screening by blood pressure machine with atrial fibrillation detection algorithms. Participants who received a positive result on 1 or more test underwent 12-lead electrocardiogram with or withour 24-hour Holter. Screening tests were compared using the McNemar test. Participants with confirmed atrial fibrillation received follow-up at 90 days.

RESULTS

The mean age of participants was 73.7 (± 6.9) years, and 53.4% of participants were female. Of 2171 patients, we had data from all 3 screening tests for 2054 patients. Both single-lead electrocardiogram and the blood pressure device showed superior specificity compared with pulse-check (p < 0.001 for each). Fifty-six patients (2.7%) had confirmed atrial fibrillation: 12 patients had newly detected atrial fibrillation (none of the patients were using anticoagulation agents), and 44 patients had previously diagnosed atrial fibrillation (42 patients were receiving anticoagulant therapy, 2 were not). Thus, 14 patients had actionable atrial fibrillation (0.7%). By 90 days, 77% of patients with actionable atrial fibrillation had started anticoagulant therapy.

INTERPRETATION

Newer screening technologies showed superior specificity compared with a pulse-check. Screening detected undiagnosed or undertreated atrial fibrillation in 0.7% of participants, and 77% started appropriate anticoagulant therapy.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT02262351.

The lived neighborhood: understanding how people with dementia engage with their local environment

ABSTRACTBackground:In this paper, we report progress on "Neighborhoods: our people, our places" an international study about how people living with dementia interact with their neighborhoods. The ideas of social health and citizenship are drawn upon to contextualize the data and make a case for recognizing and understanding the strengths and agency of people with dementia. In particular, we address the lived experience of the environment as a route to better understanding the capabilities, capacities, and competencies of people living with dementia. In doing this, our aim is to demonstrate the contribution of social engagement and environmental support to social health.

METHODS

The study aims to "map" local spaces and networks across three field sites (Manchester, Central Scotland and Linkoping, Sweden). It employs a mix of qualitative and participatory approaches that include mobile and visual methods intended to create knowledge that will inform the design and piloting of a neighborhood-based intervention.

RESULTS

Our research shows that the neighborhood plays an active role in the lives of people with dementia, setting limits, and constraints but also offering significant opportunities, encompassing forms of help and support as yet rarely discussed in the field of dementia studies. The paper presents new and distinctive insights into the relationship between neighborhoods and everyday life for people with dementia that have important implications for the debate on social health and policy concerning dementia friendly communities.

CONCLUSION

We end by reflecting on the messages for policy and practice that are beginning to emerge from this on-going study.

Assessing the real-time activation of the cannabinoid CB1 receptor and the associated structural changes using a FRET biosensor

The cannabinoid receptor 1 (CB1) is mainly expressed in the nervous system and regulates learning, memory processes, pain and energy metabolism. However, there is no way to directly measure its activation. In this study, we constructed a CB1 intramolecular fluorescence resonance energy transfer (FRET) sensor, which could measure CB1 activation by monitoring structural changes between the third intracellular loop and the C-terminal tail. CB1 agonists induced a time- and concentration-dependent increase in the FRET signal, corresponding to a reduction in the distance between the third intracellular loop and the C-terminal tail. This, in turn, mobilized intracellular Ca²⁺, inhibited cAMP accumulation, and increased phosphorylation of the ERK1/2 MAP kinases. The activation kinetics detected using this method were consistent with those from previous reports. Moreover, the increased FRET signal was markedly inhibited by the CB1 antagonist rimonabant, which also reduced phosphorylation of the ERK1/2 MAP kinases. We mutated a single cysteine residue in the sensor (at position 257 or 264) to alanine. Both mutation reduced the agonist-induced increase in FRET signal and structural changes in the CB1 receptor, which attenuated phosphorylation of the ERK1/2 MAP kinases. In summary, our sensor directly assesses the kinetics of CB1 activation in real-time and can be used to monitor CB1 structure and function.

Abstract B156: Discovery and characterization of AZ6197, a potent and selective ERK1/2 inhibitor

The RAS/MAPK pathway is a major driver in oncogenesis and is dysregulated in approximately 30% of human cancers, primarily by mutations in BRAF or RAS genes. The extracellular-signal-regulated kinases (ERK1 and ERK2) serve as key central nodes within this pathway. The feasibility of targeting the RAS/MAPK pathway has been demonstrated by the initial positive clinical responses observed to BRAF and MEK inhibitors in BRAF V600E/K metastatic melanoma; however, resistance frequently develops by reactivation of the RAS/MAPK pathway. Direct targeting of ERK1/2 may provide another therapeutic option in tumors with mutations in BRAF or RAS genes and, importantly, may overcome acquired resistance to RAF and MEK inhibitors where RAS/MAPK pathway reactivation has occurred, such as relapsed BRAF V600E/K melanoma. Here we describe the discovery and characterization of compound 35 (Ward et al., J Med Chem 2017 27;60), also known as AZ6197. AZ6197 is a highly potent and selective inhibitor of ERK1 and ERK2, with IC50 of &lt;1nM in biochemical assays. AZ6197 reduces cellular phospho-p90RSK1 levels in BRAF and RAS mutant cancer cell lines and inhibits proliferation of cancer cell lines exhibiting dysregulation of RAS/MAPK pathway signaling, including cell lines with mutations in BRAF, NRAS, or KRAS. AZ6197 is also active in multiple BRAF- and MEK- inhibitor resistant A375 melanoma cell lines, which have acquired a range of mutations that reactivate the RAS/MAPK pathway. In tumor xenograft models, AZ6197 reduces the pharmacodynamic (PD) biomarkers phospho-p90RSK1 and phospho-FRA1 in tumors in line with compound exposure levels, and induces significant tumor regression in the KRAS mutant NSCLC Calu 6 xenograft model. AZ6197 can be combined safely and effectively with the MEK1/2 inhibitor selumetinib in KRAS mutant NSCLC xenograft models, and this simultaneous targeting of MEK and ERK leads to synergistic tumor regressions being observed in multiple xenografts. In summary, AZ6197 is a potent and selective ERK1/2 inhibitor with activity in cell lines and tumor xenograft models with RAS/MAPK pathway activation. AZ6197 also has significant activity in BRAF mutant melanoma cell lines in which resistance to RAF and MEK inhibitors is due to the acquisition of NRAS and MEK1 mutations. Combination treatment of AZ6197 and the MEK1/2 inhibitor selumetinib drives synergistic tumor regression in multiple KRAS mutant xenograft models.

Citation Format: Vikki Flemington, Iain Simpson, Emma Davies, David Robinson, Nicola Lindsay, Lyndsey Hanson, Philip Hopcroft, Michael Tonge, Karen Roberts, Richard Ward. Discovery and characterization of AZ6197, a potent and selective ERK1/2 inhibitor [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B156.

Short communication: Variability in milk urea nitrogen and dairy total mixed ration composition in the northeastern United States

The main objective of this survey was to examine variability in milk urea nitrogen (MUN) for Dairy Herd Improvement Association (DHIA) herds in the northeastern United States (the Northeast), examine trends in dairy cow diet composition, and determine potential relationships for MUN and diet composition. Trends in milk fat and protein concentrations, milk yield, days in milk on test day, and lactation number of the cows were also evaluated. The data set for the survey included 10,839,461 DHIA dairy cow records from 2004 to 2015 for 13 states (CT, DE, MA, MD, ME, NH, NJ, NY, PA, RI, VA, VT, and WV) and was retrieved from Dairy Records Management Systems (Raleigh, NC). Average (across states and years) milk yield, milk fat, and milk protein were 31.6 ± 0.24 kg/d, 3.85 ± 0.021%, and 3.13 ± 0.013%, respectively. No obvious trends were observed for milk fat or protein content, but milk yield steadily increased during the survey period. Milk urea N concentration averaged 13.3 ± 0.13 mg/dL, with no obvious or consistent trends. Examination of variability in dairy feed cost and all milk price for the Northeast indicated that high MUN generally coincided with high feed cost and high milk price. For the diet composition survey, 9,707 records of total mixed ration (TMR) analyses, unrelated to the milk composition data set, from the Cumberland Valley Analytical Service (Maugansville, MD) database were examined. Concentration of TMR crude protein (CP) decreased from 17.1% in 2007 to 16.4% in 2015, but there was not an obvious trend in soluble protein concentration. Concentration of TMR neutral detergent fiber (NDF) and 24-h in vitro NDF degradability declined steadily during the survey period and was accompanied by a steady increase in TMR starch concentration. Examination of these unrelated data sets revealed lack of correlation between MUN and diet chemical composition. Thus, we conclude that individual cow MUN in Northeast dairy herds fluctuated between 2004 and 2015. It appeared that MUN followed variability in feed cost; however, ration feed ingredient data were not available to better define the reasons for the variations in MUN.