PHLPP1 regulates CFTR activity and lumen expansion through AMPK.

Complex organ development depends on single lumen formation and its expansion during tubulogenesis. This can be achieved by correct mitotic spindle orientation during cell division, combined with luminal fluid filling that generates hydrostatic pressure. Using a human 3D cell culture model, we have identified two regulators of these processes. We find that pleckstrin homology leucine-rich repeat protein phosphatase (PHLPP) 2 regulates mitotic spindle orientation, and thereby midbody positioning and maintenance of a single lumen. Silencing the sole PHLPP family phosphatase in Drosophila melanogaster, phlpp, resulted in defective spindle orientation in Drosophila neuroblasts. Importantly, cystic fibrosis transmembrane conductance regulator (CFTR) is the main channel regulating fluid transport in this system, stimulated by phosphorylation by protein kinase A and inhibited by the AMP-activated protein kinase AMPK. During lumen expansion, CFTR remains open through the action of PHLPP1, which stops activated AMPK from inhibiting ion transport through CFTR. In the absence of PHLPP1, the restraint on AMPK activity is lost and this tips the balance in the favour of channel closing, resulting in the lack of lumen expansion and accumulation of mucus.

DNA ploidy and PTEN as biomarkers for predicting aggressive disease in prostate cancer patients under active surveillance.

BACKGROUND: Current risk stratification tools for prostate cancer patients under active surveillance (AS) may inadequately identify those needing treatment. We investigated DNA ploidy and PTEN as potential biomarkers to predict aggressive disease in AS patients. METHODS: We assessed DNA ploidy by image cytometry and PTEN protein expression by immunohistochemistry in 3197 tumour-containing tissue blocks from 558 patients followed in AS at a Norwegian local hospital. The primary endpoint was treatment, with treatment failure (biochemical recurrence or initiation of salvage therapy) as the secondary endpoint. RESULTS: The combined DNA ploidy and PTEN (DPP) status at diagnosis was associated with treatment-free survival in univariable- and multivariable analysis, with a HR for DPP-aberrant vs. DPP-normal tumours of 2.12 (p < 0.0001) and 1.94 (p < 0.0001), respectively. Integration of DNA ploidy and PTEN status with the Cancer of the Prostate Risk Assessment (CAPRA) score improved risk stratification (c-index difference = 0.025; p = 0.0033). Among the treated patients, those with DPP-aberrant tumours exhibited a significantly higher likelihood of treatment failure (HR 2.01; p = 0.027). CONCLUSIONS: DNA ploidy and PTEN could serve as additional biomarkers to identify AS patients at increased risk of developing aggressive disease, enabling earlier intervention for nearly 50% of the patients that will eventually receive treatment with current protocol.

The Geriatric Prognostic Index: a clinical prediction model for survival of older diffuse large B-cell lymphoma patients treated with standard immunochemotherapy.

The International prognostic Index (IPI) is the most widely used clinical prediction model for diffuse large B-cell lymphoma (DLBCL) patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP), but may be suboptimal in older patients. We aimed to develop and externally validate a clinical prediction model for older, RCHOP- treated DLBCL patients by examining geriatric assessment and lymphoma-related parameters in real-world cohorts. A population-based training set of 365 R-CHOP-treated DLBCL patients ≥70 years was identified through the Cancer Registry of Norway. The external test set consisted of a population-based cohort of 193 patients. Data on candidate predictors were retrieved from the Cancer Registry and through review of clinical records. Cox regression models for 2-year overall survival were used for model selection. Activities of daily living, the Charlson Comorbidity Index, age, sex, albumin, stage, Eastern Cooperative Oncology Group performance status and lactate dehydrogenase level were identified as independent predictors and combined into a Geriatric Prognostic Index (GPI). The GPI demonstrated good discrimination (optimismcorrected C-index 0.752), and identified low-, intermediate- and high-risk groups with significantly different survivals (2- year overall survival, 94%, 65%, and 25%, respectively). At external validation, the continuous and grouped GPI demonstrated good discrimination (C-index 0.727 and 0.710, respectively) and the GPI groups had significantly different survivals (2-year overall survival 95%, 65%, and 44%, respectively). Both the continuous and grouped GPI showed better discrimination than the IPI, revised-IPI and National Comprehensive Cancer Network (NCCN)-IPI (C-index 0.621, 0.583, and 0.670, respectively). In conclusion, we have developed and externally validated a GPI for older DLBCL patients treated with R-CHOP that outperformed the IPI, revised-IPI and NCCN-IPI. A web-based calculator is available at https://wide.shinyapps. io/GPIcalculator/.

A clinical decision support system optimising adjuvant chemotherapy for colorectal cancers by integrating deep learning and pathological staging markers: a development and validation study.

BACKGROUND: The DoMore-v1-CRC marker was recently developed using deep learning and conventional haematoxylin and eosin-stained tissue sections, and was observed to outperform established molecular and morphological markers of patient outcome after primary colorectal cancer resection. The aim of the present study was to develop a clinical decision support system based on DoMore-v1-CRC and pathological staging markers to facilitate individualised selection of adjuvant treatment. METHODS: We estimated cancer-specific survival in subgroups formed by pathological tumour stage (pT<4 or pT4), pathological nodal stage (pN0, pN1, or pN2), number of lymph nodes sampled (≤12 or >12) if not pN2, and DoMore-v1-CRC classification (good, uncertain, or poor prognosis) in 997 patients with stage II or III colorectal cancer considered to have no residual tumour (R0) from two community-based cohorts in Norway and the UK, and used these data to define three risk groups. An external cohort of 1075 patients with stage II or III R0 colorectal cancer from the QUASAR 2 trial was used for validation; these patients were treated with single-agent capecitabine. The proposed risk stratification system was evaluated using Cox regression analysis. We similarly evaluated a risk stratification system intended to reflect current guidelines and clinical practice. The primary outcome was cancer-specific survival. FINDINGS: The new risk stratification system provided a hazard ratio of 10·71 (95% CI 6·39-17·93; p<0·0001) for high-risk versus low-risk patients and 3·06 (1·73-5·42; p=0·0001) for intermediate versus low risk in the primary analysis of the validation cohort. Estimated 3-year cancer-specific survival was 97·2% (95% CI 95·1-98·4; n=445 [41%]) for the low-risk group, 94·8% (91·7-96·7; n=339 [32%]) for the intermediate-risk group, and 77·6% (72·1-82·1; n=291 [27%]) for the high-risk group. The guideline-based risk grouping was observed to be less prognostic and informative (the low-risk group comprised only 142 [13%] of the 1075 patients). INTERPRETATION: Integrating DoMore-v1-CRC and pathological staging markers provided a clinical decision support system that risk stratifies more accurately than its constituent elements, and identifies substantially more patients with stage II and III colorectal cancer with similarly good prognosis as the low-risk group in current guidelines. Avoiding adjuvant chemotherapy in these patients might be safe, and could reduce morbidity, mortality, and treatment costs. FUNDING: The Research Council of Norway.

Centrosomal ALIX regulates mitotic spindle orientation by modulating astral microtubule dynamics.

The orientation of the mitotic spindle (MS) is tightly regulated, but the molecular mechanisms are incompletely understood. Here we report a novel role for the multifunctional adaptor protein ALG-2-interacting protein X (ALIX) in regulating MS orientation in addition to its well-established role in cytokinesis. We show that ALIX is recruited to the pericentriolar material (PCM) of the centrosomes and promotes correct orientation of the MS in asymmetrically dividing Drosophila stem cells and epithelial cells, and symmetrically dividing Drosophila and human epithelial cells. ALIX-deprived cells display defective formation of astral microtubules (MTs), which results in abnormal MS orientation. Specifically, ALIX is recruited to the PCM via Drosophila Spindle defective 2 (DSpd-2)/Cep192, where ALIX promotes accumulation of γ-tubulin and thus facilitates efficient nucleation of astral MTs. In addition, ALIX promotes MT stability by recruiting microtubule-associated protein 1S (MAP1S), which stabilizes newly formed MTs. Altogether, our results demonstrate a novel evolutionarily conserved role of ALIX in providing robustness to the orientation of the MS by promoting astral MT formation during asymmetric and symmetric cell division.

Deep learning for prediction of colorectal cancer outcome: a discovery and validation study.

BACKGROUND: Improved markers of prognosis are needed to stratify patients with early-stage colorectal cancer to refine selection of adjuvant therapy. The aim of the present study was to develop a biomarker of patient outcome after primary colorectal cancer resection by directly analysing scanned conventional haematoxylin and eosin stained sections using deep learning. METHODS: More than 12 000 000 image tiles from patients with a distinctly good or poor disease outcome from four cohorts were used to train a total of ten convolutional neural networks, purpose-built for classifying supersized heterogeneous images. A prognostic biomarker integrating the ten networks was determined using patients with a non-distinct outcome. The marker was tested on 920 patients with slides prepared in the UK, and then independently validated according to a predefined protocol in 1122 patients treated with single-agent capecitabine using slides prepared in Norway. All cohorts included only patients with resectable tumours, and a formalin-fixed, paraffin-embedded tumour tissue block available for analysis. The primary outcome was cancer-specific survival. FINDINGS: 828 patients from four cohorts had a distinct outcome and were used as a training cohort to obtain clear ground truth. 1645 patients had a non-distinct outcome and were used for tuning. The biomarker provided a hazard ratio for poor versus good prognosis of 3·84 (95% CI 2·72-5·43; p<0·0001) in the primary analysis of the validation cohort, and 3·04 (2·07-4·47; p<0·0001) after adjusting for established prognostic markers significant in univariable analyses of the same cohort, which were pN stage, pT stage, lymphatic invasion, and venous vascular invasion. INTERPRETATION: A clinically useful prognostic marker was developed using deep learning allied to digital scanning of conventional haematoxylin and eosin stained tumour tissue sections. The assay has been extensively evaluated in large, independent patient populations, correlates with and outperforms established molecular and morphological prognostic markers, and gives consistent results across tumour and nodal stage. The biomarker stratified stage II and III patients into sufficiently distinct prognostic groups that potentially could be used to guide selection of adjuvant treatment by avoiding therapy in very low risk groups and identifying patients who would benefit from more intensive treatment regimes. FUNDING: The Research Council of Norway.

Change in Body Weight and Long-Term Risk of Stroke and Death in Healthy Men.

Background and Purpose- The importance of weight change for the risk of stroke is not well known. We examined the associations between early- and mid-life weight change and risks of stroke and death during long-term follow-up of healthy men. Methods- We recruited healthy men aged between 40 and 59 years and performed a cardiovascular examination at baseline and again at 7 years. We collected data on weight change since the age of 25 (early-life weight change) and measured weight change from baseline to the visit at 7 years (mid-life weight change). For both weight change periods, participants were divided into the following categories: weight loss, weight gain 0 to 4.9 kg, weight gain 5 to 9.9 kg, and weight gain ≥10 kg. Data on stroke and death were collected up to 35 years, from study visits, hospital records, and the National Cause of Death Registry. We used Cox regression to analyze the associations between weight change during early-life and mid-life and risks of stroke and death. Results- Of the 2014 participants, 2014 (100%) had data on early-life weight change and were followed for a median of 30.1 years, while 1403 had data on mid-life weight change and were followed for a median of 24.6 years. During early-life, compared with those who had weight gain 0 to 4.9 kg, hazard ratio for stroke was 1.46 (95% CI, 1.09-1.95) among those with weight gain 5 to 9.9 kg, 1.39 (95% CI, 1.03-1.87) for those with weight gain ≥10 kg, and 1.46 (95% CI, 0.99-2.11) among those with weight loss. For all-cause death, the hazard ratios were 1.08 (95% CI, 0.92-1.23), 1.14 (95% CI, 0.98-1.33), and 1.29 (95% CI, 1.06-1.56), respectively. During mid-life, there were no significant differences in risk of stroke or death between the groups. Conclusions- Weight increase during early-life, but not mid-life, seems to be associated with increased long-term risk of stroke in healthy men. If these findings can be confirmed, efforts to prevent weight increase should target the younger population.

Prognostic value of mitotic checkpoint protein BUB3, cyclin B1, and pituitary tumor-transforming 1 expression in prostate cancer.

The mitotic checkpoint protein BUB3, cyclin B1 (CCNB1) and pituitary tumor-transforming 1 (PTTG1) regulates cell division, and are sparsely studied in prostate cancer. Deregulation of these genes can lead to genomic instability, a characteristic of more aggressive tumors. We aimed to determine the expression levels of BUB3, CCNB1, and PTTG1 as potential prognostic markers of recurrence after radical prostatectomy. Protein levels were determined by immunohistochemistry on three formalin-fixed paraffin-embedded tissue sections from each of the 253 patients treated with radical prostatectomy. Immunohistochemistry scores were obtained by automated image analysis for CCNB1 and PTTG1. Recurrence, defined as locoregional recurrence, distant metastasis or death from prostate cancer, was used as endpoint for survival analysis. Tumors having both positive and negative tumor areas for cytoplasmic BUB3 (30%), CCNB1 (28%), or PTTG1 (35%) were considered heterogeneous. Patients with ≥1 positive tumor area had significantly increased risk of disease recurrence in univariable analysis compared with patients where all tumor areas were negative for cytoplasmic BUB3 (hazard ratio [HR] = 2.18, 95% confidence interval [CI] 1.41-3.36), CCNB1 (HR = 2.98, 95% CI 1.93-4.61) and PTTG1 (HR = 1.91, 95% CI 1.23-2.97). Combining the scores of cytoplasmic BUB3 and CCNB1 improved risk stratification when integrated with the Cancer of the Prostate Risk Assessment post-Surgical (CAPRA-S) score (difference in concordance index = 0.024, 95% CI 0.001-0.05). In analysis of multiple tumor areas, prognostic value was observed for cytoplasmic BUB3, CCNB1, and PTTG1.

Ten-year prediction of cardiovascular disease in healthy Norwegian men, based on NORRISK-2. / Tiårsprediksjon av hjerte- og karsykdom hos friske norske menn basert på NORRISK-2.

BACKGROUND: Norwegian guidelines for primary prevention of cardiovascular disease recommend the use of the NORRISK-2 risk model, with some additions. We wished to investigate whether NORRISK-2 could predict cardiovascular disease in healthy Norwegian men who took part in the Oslo Ischaemia Study. MATERIAL: NORRISK-2 scores were calculated for 2 014 men in the age group 40-60 years who were included in the Oslo Ischaemia Study in 1972-75. Cox regression analyses were used to calculate the hazard ratio for death and cardiovascular disease within ten years of the participants' initial assessment. RESULTS: No participant was lost to follow-up of the 2 014 men, 125 died in the first ten years after inclusion, 61 of whom died from cardiovascular disease. Those who died were older than those who survived, with a larger proportion of daily smokers, and they had higher systolic blood pressure and resting pulse, increased total cholesterol and lower physical fitness. The majority of those who died from acute myocardial infarction and ischaemic stroke within ten years were classified in the high-risk group in NORRISK-2. INTERPRETATION: NORRISK-2 satisfactorily identified the high-risk persons in this cohort of healthy, middle-aged Norwegian men. This supports use of the Norwegian guidelines in the decision on possible primary protection against cardiovascular disease.

Change in Cardiorespiratory Fitness and Risk of Stroke and Death: Long-Term Follow-Up of Healthy Middle-Aged Men.

Background and Purpose- Low cardiorespiratory fitness is associated with increased risk of cardiovascular disease. The present study aims to assess whether change of fitness over time has any impact on long-term risk of stroke and death. Methods- We recruited healthy men aged 40 to 59 years in 1972 to 1975, and followed them until 2007. Physical fitness was assessed with a bicycle ECG test at baseline and again at 7 years, by dividing the total exercise work by body weight. Participants were categorized as remained fit, became unfit, remained unfit, or became fit, depending on whether fitness remained or crossed the median values from baseline to the 7-year visit. Outcome data were collected up to 35 years, from study visits, hospital records, and the National Cause of Death Registry. Risks of stroke and death were estimated by Cox regression analyses and expressed as hazard ratios (HRs) with 95% CIs. Results- Of 2014 participants, 1403 were assessed both at baseline and again at 7 years, and were followed for a mean of 23.6 years. Compared with the became unfit group, risk of stroke was 0.85 (0.54-1.36) for the remained unfit, 0.43 (0.28-0.67) for the remained fit, and 0.34 (0.17-0.67) for the became fit group. For all-cause death, risks were 0.99 (0.76-1.29), 0.57 (0.45-0.74), and 0.65 (0.46-0.90), respectively. Among those with high fitness at baseline, the became unfit group had a significantly higher risk of stroke (HR, 2.35; CI, 1.49-3.63) and death (HR, 1.74; CI, 1.35-2.23) than those who remained fit. Among those who had low fitness at baseline, the became fit group had a significantly lower risk of stroke (HR, 0.40; CI, 0.21-0.72) and death (HR, 0.66; CI, 0.50-0.85) than participants in the remained unfit group. Conclusions- Cardiorespiratory fitness at baseline and change in fitness was associated with large changes in long-term risk of stroke and death. These findings support the encouragement of regular exercise as a stroke prevention strategy.

Distinct patterns of B-cell receptor signaling in non-Hodgkin lymphomas identified by single-cell profiling.

Kinases downstream of B-cell antigen receptor (BCR) represent attractive targets for therapy in non-Hodgkin lymphoma (NHL). As clinical responses vary, improved knowledge regarding activation and regulation of BCR signaling in individual patients is needed. Here, using phosphospecific flow cytometry to obtain malignant B-cell signaling profiles from 95 patients representing 4 types of NHL revealed a striking contrast between chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) tumors. Lymphoma cells from diffuse large B-cell lymphoma patients had high basal phosphorylation levels of most measured signaling nodes, whereas follicular lymphoma cells represented the opposite pattern with no or very low basal levels. MCL showed large interpatient variability in basal levels, and elevated levels for the phosphorylated forms of AKT, extracellular signal-regulated kinase, p38, STAT1, and STAT5 were associated with poor outcome. CLL tumors had elevated basal levels for the phosphorylated forms of BCR-signaling nodes (Src family tyrosine kinase, spleen tyrosine kinase [SYK], phospholipase Cγ), but had low α-BCR-induced signaling. This contrasted MCL tumors, where α-BCR-induced signaling was variable, but significantly potentiated as compared with the other types. Overexpression of CD79B, combined with a gating strategy whereby signaling output was directly quantified per cell as a function of CD79B levels, confirmed a direct relationship between surface CD79B, immunoglobulin M (IgM), and IgM-induced signaling levels. Furthermore, α-BCR-induced signaling strength was variable across patient samples and correlated with BCR subunit CD79B expression, but was inversely correlated with susceptibility to Bruton tyrosine kinase (BTK) and SYK inhibitors in MCL. These individual differences in BCR levels and signaling might relate to differences in therapy responses to BCR-pathway inhibitors.

Blood pressure variability in hypertensive patients with atrial fibrillation in the VALUE trial.

PURPOSE: Blood pressure variability is associated with traditional cardiovascular risk factors, but little is known about the association with atrial fibrillation. We compared blood pressure variability in patients with and without atrial fibrillation using data from the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial. MATERIALS AND METHODS: The VALUE trial was a randomised-controlled trial of valsartan versus amlodipine in patients with hypertension and high cardiovascular risk, followed for 4.2 years (mean). For the present analysis we included patients with electrocardiogram at baseline and during follow-up, and ≥3 visits from 6 months onwards. We compared standard deviation (SD) of all blood pressures within each visit averaged across all visits (within-visit variability) and of mean blood pressure at each visit (visit-to-visit variability) in patients with and without atrial fibrillation at baseline. We similarly compared patients who developed non-persistent or persistent atrial fibrillation during follow-up with those who did not, using t-tests, ANOVA and linear regression. RESULTS: Of 15,245 patients in the VALUE trial, 13,827 were eligible for analysis. SD of visit-to-visit systolic blood pressure was not significantly different between patients with and without atrial fibrillation at baseline (mean difference 0.3 mm Hg, p = 0.4), but significantly higher in patients with incident non-persistent or persistent atrial fibrillation during follow-up than in those who never developed atrial fibrillation (differences 1.2 and 1.8 mm Hg, respectively, p-values <0.0001). Associations with non-persistent and persistent atrial fibrillation were confirmed in linear regression models (p-values <0.0001). SD of within-visit systolic blood pressure was not significantly different between patients with and without atrial fibrillation at baseline (p = 0.4) but significantly higher in patients with persistent atrial fibrillation during follow-up (p = 0.04). CONCLUSION: In patients treated for hypertension, atrial fibrillation was not associated with increased blood pressure variability, but blood pressure variability was higher in those who developed atrial fibrillation during follow-up.

Blood pressure variability and risk of cardiovascular events and death in patients with hypertension and different baseline risks.

Aims: Blood pressure variability is associated with increased risk of cardiovascular events, particularly in high-risk patients. We assessed if variability was associated with increased risk of cardiovascular events and death in hypertensive patients at different risk levels. Methods and results: The Valsartan Antihypertensive Long-term Use Evaluation trial was a randomized controlled trial of valsartan vs. amlodipine in patients with hypertension and different risks of cardiovascular events, followed for a mean of 4.2 years. We calculated standard deviation (SD) of mean systolic blood pressure from visits from 6 months onward in patients with ≥3 visits and no events during the first 6 months. We compared the risk of cardiovascular events in the highest and lowest quintile of visit-to-visit blood pressure variability, using Cox regression. For analysis of death, variability was analysed as a continuous variable. Of 13 803 patients included, 1557 (11.3%) had a cardiovascular event and 1089 (7.9%) died. Patients in the highest quintile of SD had an increased risk of cardiovascular events [hazard ratio (HR) 2.1, 95% confidence interval (95% CI) 1.7-2.4; P < 0.0001], and a 5 mmHg increase in SD of systolic blood pressure was associated with a 10% increase in the risk of death (HR 1.10, 95% CI 1.04-1.17; P = 0.002). Associations were stronger among younger patients and patients with lower systolic blood pressure, and similar between patients with different baseline risks, except for higher risk of death among patients with established cardiovascular disease. Conclusion: Higher visit-to-visit systolic blood pressure variability is associated with increased risk of cardiovascular events in patients with hypertension, irrespective of baseline risk of cardiovascular events. Associations were stronger in younger patients and in those with lower mean systolic blood pressure.

Src64 controls a novel actin network required for proper ring canal formation in the Drosophila male germline.

In many organisms, germ cells develop as cysts in which cells are interconnected via ring canals (RCs) as a result of incomplete cytokinesis. However, the molecular mechanisms of incomplete cytokinesis remain poorly understood. Here, we address the role of tyrosine phosphorylation of RCs in the Drosophila male germline. We uncover a hierarchy of tyrosine phosphorylation within germline cysts that positively correlates with RC age. The kinase Src64 is responsible for mediating RC tyrosine phosphorylation, and loss of Src64 causes a reduction in RC diameter within germline cysts. Mechanistically, we show that Src64 controls an actin network around the RCs that depends on Abl and the Rac/SCAR/Arp2/3 pathway. The actin network around RCs is required for correct RC diameter in cysts of developing germ cells. We also identify that Src64 is required for proper germ cell differentiation in the Drosophila male germline independent of its role in RC regulation. In summary, we report that Src64 controls actin dynamics to mediate proper RC formation during incomplete cytokinesis during germline cyst development in vivo.

Evaluating different breast tumor progression models using screening data.

BACKGROUND: Mammography screening is used to detect breast cancer at an early treatable stage, reducing breast cancer mortality. Traditionally, breast cancer has been seen as a disease with only progressive lesions, and here we examine the validity of this assumption by testing if incidence levels after introducing mammography screening can be reproduced assuming only progressive tumors. METHODS: Breast cancer incidence data 1990-2009 obtained from the initially screened Norwegian counties (Akershus, Oslo, Rogaland and Hordaland) was included, covering the time-period before, during and after the introduction of mammography screening. From 1996 women aged 50-69 were invited for biennial public screening. Using estimates of tumor growth and screening sensitivity based on pre-screening and prevalence screening data (1990-1998), we simulated incidence levels during the following period (1999-2009). RESULTS: The simulated incidence levels during the period with repeated screenings were markedly below the observed levels. The results were robust to changes in model parameters. Adjusting for hormone replacement therapy use, we obtained levels closer to the observed levels. However, there was still a marked gap, and only by assuming some tumors that undergo regressive changes or enter a markedly less detectable state, was our model able to reproduce the observed incidence levels. CONCLUSIONS: Models with strictly progressive tumors are only able to partly explain the changes in incidence levels observed after screening introduction in the initially screened Norwegian counties. More complex explanations than a time shift in detection of future clinical cancers seem to be needed to reproduce the incidence trends, questioning the basis for many over-diagnosis calculations. As data are not randomized, similar studies in other populations are wanted to exclude effect of unknown confounders.

ALIX and ESCRT-III coordinately control cytokinetic abscission during germline stem cell division in vivo.

Abscission is the final step of cytokinesis that involves the cleavage of the intercellular bridge connecting the two daughter cells. Recent studies have given novel insight into the spatiotemporal regulation and molecular mechanisms controlling abscission in cultured yeast and human cells. The mechanisms of abscission in living metazoan tissues are however not well understood. Here we show that ALIX and the ESCRT-III component Shrub are required for completion of abscission during Drosophila female germline stem cell (fGSC) division. Loss of ALIX or Shrub function in fGSCs leads to delayed abscission and the consequent formation of stem cysts in which chains of daughter cells remain interconnected to the fGSC via midbody rings and fusome. We demonstrate that ALIX and Shrub interact and that they co-localize at midbody rings and midbodies during cytokinetic abscission in fGSCs. Mechanistically, we show that the direct interaction between ALIX and Shrub is required to ensure cytokinesis completion with normal kinetics in fGSCs. We conclude that ALIX and ESCRT-III coordinately control abscission in Drosophila fGSCs and that their complex formation is required for accurate abscission timing in GSCs in vivo.

Interaction with epsin 1 regulates the constitutive clathrin-dependent internalization of ErbB3.

BACKGROUND: In contrast to other members of the EGF receptor family, ErbB3 is constitutively internalized in a clathrin-dependent manner. Previous studies have shown that ErbB3 does not interact with the coated pit localized adaptor complex 2 (AP-2), and that ErbB3 lacks two AP-2 interacting internalization signals identified in the EGF receptor. Several other clathrin-associated sorting proteins which may recruit cargo into coated pits have, however, been identified, and the study was performed to identify adaptors needed for constitutive internalization of ErbB3. METHODS: A high-throughput siRNA screen was used to identify adaptor proteins needed for internalization of ErbB3. Upon knock-down of candidate proteins internalization of ErbB3 was identified using an antibody-based internalization assay combined with automatic fluorescence microscopy. RESULTS: Among 29 candidates only knock-down of epsin 1 turned out to inhibit ErbB3. Epsin 1 has ubiquitin interacting motifs (UIMs) and we show that ErbB3 interacts with an epsin 1 deletion mutant containing these UIMs. In support of an ErbB3-epsin 1 UIM dependent interaction, we show that ErbB3 is constitutively ubiquitinated, but that both ubiquitination and the ErbB3-epsin 1 interaction increase upon ligand binding. CONCLUSION: Altogether the results are consistent with a model whereby both constitutive and ligand-induced internalization of ErbB3 are regulated through interaction with epsin 1. GENERAL SIGNIFICANCE: Internalization is an important regulator of growth factor receptor mediated signaling and the current study identify mechanisms regulating plasma membrane turnover of ErbB3.

Exercise systolic blood pressure at moderate workload predicts cardiovascular disease and mortality through 35 years of follow-up in healthy, middle-aged men.

OBJECTIVE: There is an association between exercise systolic blood pressure (SBP) and cardiovascular disease and mortality. The aim of this study was to investigate this association, with 35 years of follow-up. METHODS: Through 1972-75, 2014 healthy, middle-aged men underwent thorough medical examination and a bicycle exercise test. 1999 participants completed six minutes at 100 W. SBP was measured manually, both before the test and every two minutes during the test. Highest SBP measured during the first six minutes (SBP100W) was used in further analyses. RESULTS: Participants were divided into quartiles (Q) based on their SBP100W; Q1: 100-160 mm Hg (n = 457), Q2: 165-175 mm Hg (n = 508), Q3: 180-195 mm Hg (n = 545) and Q4: 200-275 mm Hg (n = 489). After 35-years follow-up, there was a significant association between exercise SBP at baseline and cardiovascular disease and mortality. In the multivariate analysis adjusting for resting SBP, age, smoking status, total serum cholesterol and family history of coronary heart disease, as well as physical fitness, there is a 1.39-fold (CI: 1.00-1.93, p = 0.05) increased risk of cardiovascular mortality in Q4 compared to Q1. When not adjusting for physical fitness, there is a 1.29-fold (CI: 1.03-1.61, p = 0.02) increase in risk of cardiovascular disease between Q1 and Q4. CONCLUSIONS: The results of this study suggest that the association between exercise SBP at moderate workload and cardiovascular disease and mortality in middle-aged men extends through as long as 35 years and into old ages.

Photoactivation approaches reveal a role for Rab11 in FGFR4 recycling and signalling.

Fibroblast growth factor receptor 4 (FGFR4) plays important roles during development and in the adult to maintain tissue homeostasis. Moreover, overexpression of FGFR4 or activating mutations in FGFR4 has been identified as tumour-promoting events in several forms of cancer. Endocytosis is important for regulation of signalling receptors and we have previously shown that FGFR4 is mainly localized to transferrin-positive structures after ligand-induced endocytosis. Here, using a cell line with a defined pericentriolar endocytic recycling compartment, we show that FGFR4 accumulates in this compartment after endocytosis. Furthermore, using classical recycling assays and a new, photoactivatable FGFR4-PA-GFP fusion protein combined with live-cell imaging, we demonstrate that recycling of FGFR4 is dependent on Rab11. Upon Rab11b depletion, FGFR4 is trapped in the pericentriolar recycling compartment and the total levels of FGFR4 in cells are increased. Moreover, fibroblast growth factor 1 (FGF1)-induced autophosphorylation of FGFR4 as well as phosphorylation of phospholipase C (PLC)-γ is prolonged in cells depleted of Rab11. Interestingly, the activation of mitogen-activated protein kinase and AKT pathways were not prolonged but rather reduced in Rab11-depleted cells, indicating that recycling of FGFR4 is important for the nature of its signalling output. Thus, Rab11-dependent recycling of FGFR4 maintains proper levels of FGFR4 in cells and regulates FGF1-induced FGFR4 signalling.