Robert Lerrigo

Aurora A Regulates the Activity of HURP by Controlling the Accessibility of Its Microtubule-binding Domain

HURP is a spindle-associated protein that mediates Ran-GTP-dependent assembly of the bipolar spindle and promotes chromosome congression and interkinetochore tension during mitosis. We report here a biochemical mechanism of HURP regulation by Aurora A, a key mitotic kinase that controls the assembly and function of the spindle. We found that HURP binds to microtubules through its N-terminal domain that hyperstabilizes spindle microtubules. Ectopic expression of this domain generates defects in spindle morphology and function that reduce the level of tension across sister kinetochores and activate the spindle checkpoint. Interestingly, the microtubule binding activity of this N-terminal domain is regulated by the C-terminal region of HURP: in its hypophosphorylated state, C-terminal HURP associates with the microtubule-binding domain, abrogating its affinity for microtubules. However, when the C-terminal domain is phosphorylated by Aurora A, it no longer binds to N-terminal HURP, thereby releasing the inhibition on its microtubule binding and stabilizing activity. In fact, ectopic expression of this C-terminal domain depletes endogenous HURP from the mitotic spindle in HeLa cells in trans, suggesting the physiological importance for this mode of regulation. We concluded that phosphorylation of HURP by Aurora A provides a regulatory mechanism for the control of spindle assembly and function.

Cloche is a bHLH-PAS transcription factor that drives haemato-vascular specification

Vascular and haematopoietic cells organize into specialized tissues during early embryogenesis to supply essential nutrients to all organs and thus play critical roles in development and disease. At the top of the haemato-vascular specification cascade lies cloche, a gene that when mutated in zebrafish leads to the striking phenotype of loss of most endothelial and haematopoietic cells and a significant increase in cardiomyocyte numbers. Although this mutant has been analysed extensively to investigate mesoderm diversification and differentiation and continues to be broadly used as a unique avascular model, the isolation of the cloche gene has been challenging due to its telomeric location. Here we used a deletion allele of cloche to identify several new cloche candidate genes within this genomic region, and systematically genome-edited each candidate. Through this comprehensive interrogation, we succeeded in isolating the cloche gene and discovered that it encodes a PAS-domain-containing bHLH transcription factor, and that it is expressed in a highly specific spatiotemporal pattern starting during late gastrulation. Gain-of-function experiments show that it can potently induce endothelial gene expression. Epistasis experiments reveal that it functions upstream of etv2 and tal1, the earliest expressed endothelial and haematopoietic transcription factor genes identified to date. A mammalian cloche orthologue can also rescue blood vessel formation in zebrafish cloche mutants, indicating a highly conserved role in vertebrate vasculogenesis and haematopoiesis. The identification of this master regulator of endothelial and haematopoietic fate enhances our understanding of early mesoderm diversification and may lead to improved protocols for the generation of endothelial and haematopoietic cells in vivo and in vitro.Vascular and haematopoietic cells organize into specialized tissues during early embryogenesis to supply essential nutrients to all organs and thus play critical roles in development and disease. At the top of the haemato-vascular specification cascade lies cloche, a gene that when mutated in zebrafish leads to the striking phenotype of loss of most endothelial and haematopoietic cells and a significant increase in cardiomyocyte numbers. Although this mutant has been analysed extensively to investigate mesoderm diversification and differentiation and continues to be broadly used as a unique avascular model, the isolation of the cloche gene has been challenging due to its telomeric location. Here we used a deletion allele of cloche to identify several new cloche candidate genes within this genomic region, and systematically genome-edited each candidate. Through this comprehensive interrogation, we succeeded in isolating the cloche gene and discovered that it encodes a PAS-domain-containing bHLH transcription factor, and that it is expressed in a highly specific spatiotemporal pattern starting during late gastrulation. Gain-of-function experiments show that it can potently induce endothelial gene expression. Epistasis experiments reveal that it functions upstream of etv2 and tal1, the earliest expressed endothelial and haematopoietic transcription factor genes identified to date. A mammalian cloche orthologue can also rescue blood vessel formation in zebrafish cloche mutants, indicating a highly conserved role in vertebrate vasculogenesis and haematopoiesis. The identification of this master regulator of endothelial and haematopoietic fate enhances our understanding of early mesoderm diversification and may lead to improved protocols for the generation of endothelial and haematopoietic cells in vivo and in vitro.

The role of social isolation in social anxiety disorder: A systematic review and meta-analysis

INTRODUCTION Social isolation in the context of social anxiety disorder has not been closely examined. This study aimed to describe the role and measurement of social isolation in those with social anxiety disorder. METHOD A systematic review and meta-analyses were conducted using a prospectively prepared protocol for search strategy, selection criteria, and data extraction. DerSimonian-Laird random effects models were used to calculate pooled estimates of effect. RESULTS Thirty-four studies, containing 20 formal instruments and four other measures of social isolation, were included. Most formal instruments were utilized in single studies, whereas simple structural measures (e.g., living alone) were used most frequently. The pooled score was 38.1 on the Loneliness and Social Dissatisfaction Questionnaire, 33.1 on the Liebowitz Social Anxiety Scale (avoidance subscale), and 21.1 on the Social Avoidance and Distress Scale. CONCLUSIONS Social isolation is common in social anxiety disorder but assessed by a heterogeneous mix of measures.

Nonresponse to Interferon-α Based Treatment for Chronic Hepatitis C Infection Is Associated with Increased Hazard of Cirrhosis

Background The long-term consequences of unsuccessful interferon-α based hepatitis C treatment on liver disease progression and survival have not been fully explored. Methods and Findings We performed retrospective analyses to assess long-term clinical outcomes among treated and untreated patients with hepatitis C virus in two independent cohorts from a United States Veterans Affairs Medical Center and a University Teaching Hospital. Eligible patients underwent liver biopsy during consideration for interferon-α based treatment between 1992 and 2007. They were assessed for the probability of developing cirrhosis and of dying during follow-up using Cox proportional hazards models, stratified by pretreatment liver fibrosis stage and adjusted for known risk factors for cirrhosis and characteristics affecting treatment selection. The major predictor was a time-dependent covariate for treatment outcome among four patient groups: 1) patients with sustained virological response to treatment; 2) treatment relapsers; 3) treatment nonresponders; and 4) never treated patients. Treatment nonresponders in both cohorts had a statistically significantly increased hazard of cirrhosis compared to never treated patients, as stratified by pretreatment liver fibrosis stage and adjusted for clinical and psychosocial risk factors that disproportionately affect patients who were ineligible for treatment (Veterans Affairs HR = 2.35, CI 1.18–4.69, mean follow-up 10 years, and University Hospital HR = 5.90, CI 1.50–23.24, mean follow-up 7.7 years). Despite their increased risk for liver disease progression, the overall survival of nonresponders in both cohorts was not significantly different from that of never treated patients. Conclusion These unexpected findings suggest that patients who receive interferon-α based therapies but fail to clear the hepatitis C virus may have an increased hazard of cirrhosis compared to untreated patients.

Expanded use of aggressive therapies improves survival in early and intermediate hepatocellular carcinoma.

BACKGROUND Despite the increasing annual incidence of hepatocellular carcinoma (HCC) in the USA, now estimated at 2.7 cases per 100 000 population, only a small proportion of patients receive treatment and 5-year survival rates range from 9% to 17%. OBJECTIVES The present study examines the effects of multimodal treatment on survival in a mixed-stage HCC cohort, focusing on the impact of radical therapy in patients with Barcelona Clinic Liver Cancer (BCLC) stage B disease. METHODS A retrospective review of the medical records of 254 patients considered for HCC treatment between 2003 and 2011 at a large tertiary referral centre was conducted. RESULTS A total of 195 (76.8%) patients were treated with a median of two liver-directed interventions. Median survival time was 16 months. In proportional hazards analysis, radiofrequency ablation (RFA) and resection were associated with significantly improved 1- and 5-year survival among patients with BCLC stage 0-A disease. In patients with BCLC stage B disease, RFA conferred a survival benefit at 1 year and resection was associated with significantly improved survival at 5 years. CONCLUSIONS As one of few studies to track the complete course of sequential HCC therapies, the findings of the present study suggest that HCC patients with intermediate-stage (BCLC stage B) disease may benefit from aggressive interventions not currently included in societal guidelines.

Characteristics and outcomes of transjugular intrahepatic portosystemic shunt recipients in the VA Healthcare System.

Background and Aims Transjugular intrahepatic portosystemic shunt (TIPS) placement is an effective treatment for complications of portal hypertension. We aimed to describe post-TIPS mortality and its predictors in the modern era of covered stents. Patients and methods We identified patients with cirrhosis who underwent TIPS insertion at Veterans Affairs Healthcare facilities nationally from 2004 to 2014 (n=703), most of which (95%) were performed as elective procedures. We followed patients until the date of death, transplantation, or the end of the observation period. Results TIPS recipients had a mean age of 59.3 years (SD 8) and 97% were men. The mean Model for End Stage Liver Disease (MELD) score was 13 (SD 4.8); 47% had hepatitis C virus (HCV) infection, 48% had variceal hemorrhage, and 40% had ascites. During a mean follow-up of 1.72 years (SD 1.9), 57.5% of TIPS recipients died (n=404) and only 5.3% underwent liver transplantation (n=37). The median survival after TIPS was 1.74 years (interquartile range 0.3–4.7). Thirty-day mortality after TIPS was 11.6% [95% confidence interval (CI) 9.4–14.2], 1-year mortality was 40.3% (95% CI 36.7–44.2), and 3-year mortality was 61.9% (95% CI 57.9–66.0). Independent predictors of post-TIPS mortality included medical comorbidity burden, low albumin, HCV infection, and high MELD score (or high international normalized ratio and bilirubin when the components of the MELD score were analyzed individually). TIPS revision was performed at least once in 27.3% of TIPS recipients. Conclusion TIPS should not be considered simply as a bridge to transplantation. Burden of extra-hepatic comorbidities, HCV infection, and low serum albumin strongly predict post-TIPS mortality in addition to the MELD score.

Su2061 Hepatocellular Carcinoma With a Plan for Surgical Resection is Associated With Improved Survival Compared to a Plan for Liver Transplantation

Background: Over the past decade, the U.S. Department of Veterans Affairs (VA) has seen a more than 6-fold increased prevalence in hepatcocellular carcinoma (HCC). However, the treatment outcome of HCC in this population is not well characterized. Aim:Using intentionto-treat analysis to compare overall survival among patients with HCC treated by different modalities at a single VA center. Methods: 127 consecutive HCC patients, referred for consideration of therapy at the San Francisco VA between 4/2003 to 9/2007 were included, and their outcomes were reviewed in 10/2011. Based on their “intention-to-treat”, these patients were grouped into four categories: surgical resection, transplantation, curative radiofrequency ablation (RFA), and palliative treatment (palliative RFA, transarterial embolization, percutaneous ethanol injection, or none). Baseline patient characteristics, disease stage, and survival outcome using Cox proportional hazard models stratified by BCLC stages were compared. Results: The median age was 58 at initial presentation; 4% were at BCLC stage 0, 25% stage A, 54% stage B, 15% stage C, and 2% stage D. Median MELD score was 10 (range 6 to 30). Initial treatment plans were: 32 (25%) resection, 19 (15%) transplantation, 15 (12%) RFA, and 61 (48%) palliation. In this cohort, 28/32 (88%) of the resection group actually underwent resection and 12/19 (63%) of the transplant group were actually transplanted. At study end, 22 (19%) patients (10 transplant, 11 resections, 1 RFA) were alive, and 94 (80%) had died, and 1 was lost to follow-up. Mean follow-up was 29.8 months, but varied from 56.5 months in the transplant group to 16.3 months in the palliative group (p<0.0001). Stratified by BCLC stage and controlled for age and MELD score, the risk of dying was 0.39 (95% CI 0.21-0.74, p<0.004) in the resection group, 0.62 in the transplant group (95% CI 0.24-1.64, p<0.34), and 0.63 in the RFA group (95% CI 0.29-1.38, p<0.25) compared to the palliative group. Conclusion: Of patients with HCC referred for consideration of therapy at a single VA Medical Center, 52% of patients were intended to undergo curative therapy and 47% received curative therapy. Patients who were intended to undergo surgical resection fared the best compared to those intended for liver transplantation, RFA, or palliation. Surgical resection as the initial plan of treatment may be a associated with improved survival at a non-transplant center.