John Cochran Medical Center
John Cochran Medical Center
Xiao Q.,University of Washington |
Yan P.,University of Washington |
Ma X.,University of Washington |
Ma X.,John Cochran Medical Center |
And 10 more authors.
Journal of Neuroscience | Year: 2014
In sporadic Alzheimer's disease (AD), impaired Aβ removal contributes to elevated extracellular Aβ levels that drive amyloid plaque pathogenesis. Extracellular proteolysis, export across the blood- brain barrier, and cellular uptake facilitate physiologic Aβ clearance. Astrocytes can take up and degrade Aβ, but it remains unclear whether this function is insufficient inADor can be enhanced to accelerate Aβ removal. Additionally, age-related dysfunction of lysosomes, the major degradative organelles wherein Aβ localizes after uptake, has been implicated in amyloid plaque pathogenesis. We tested the hypothesis that enhancing lysosomal function in astrocytes with transcription factor EB (TFEB), a master regulator of lysosome biogenesis, would promote Aβ uptake and catabolism and attenuate plaque pathogenesis. Exogenous TFEB localized to the nucleus with transcriptional induction of lysosomal biogenesis and function in vitro. This resulted in significantly accelerated uptake of exogenously applied Aβ42, with increased localization to and degradation within lysosomes in C17.2 cells and primary astrocytes, indicating that TFEB is sufficient to coordinately enhance uptake, trafficking, and degradation of Aβ. Stereotactic injection of adeno-associated viral particles carrying TFEB driven by a glial fibrillary acidic protein promoter was used to achieve astrocyte-specific expression in the hippocampus of APP/PS1 transgenic mice. Exogenous TFEB localized to astrocyte nuclei and enhanced lysosome function, resulting in reduced Aβ levels and shortened half-life in the brain interstitial fluid and reduced amyloid plaque load in the hippocampus compared with control virus-injected mice. Therefore, activation of TFEB in astrocytes is an effective strategy to restore adequate Aβ removal and counter amyloid plaque pathogenesis in AD. © 2014 the authors.
Aft R.,John Cochran Medical Center
Cancer Causes and Control | Year: 2010
Objective: We examined racial disparities (White, African American, and other race) in health status (self-rated health, lower-body functional limitations, psychological distress, and body mass index [BMI]) and behaviors (smoking, alcohol use, and physical activity) of long-term cancer survivors (≥5 years) when compared to non-cancer controls. Methods: Using 2005-2007 National Health Interview Survey data, we computed adjusted prevalence estimates of health status and behaviors for all six groups, controlling for sociodemographic factors, medical-care access, or presence of other chronic conditions. Results: The sample included 2,762 (3.6%) survivors and 73,059 controls. Adjusted prevalence estimates for each race were higher for long-term survivors than controls in terms of having fair-poor self-rated health, ≥1 limitation, psychological distress, and higher BMI but were similar between survivors and controls in terms of physical activity, smoking, and alcohol use. Adjusted prevalence estimates for having fair-poor self-rated health were higher for African American survivors than white survivors, lower for psychological distress, physical activity and alcohol use, and similar for smoking and BMI. Conclusion: With the exception of smoking and limitations, racial differences existed among survivors for all health-status and behavioral measures. Clinicians may play a key role in helping to reduce disparities. © 2010 Springer Science+Business Media B.V.
Settembre C.,Telethon Institute of Genetics and Medicine |
Settembre C.,Baylor College of Medicine |
Diwan A.,University of Washington |
Diwan A.,John Cochran Medical Center |
And 2 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2014
OBJECTIVE - Recent reports of a proatherogenic phenotype in mice with macrophage-specific autophagy deficiency have renewed interest in the role of the autophagy-lysosomal system in atherosclerosis. Lysosomes have the unique ability to process both exogenous material, including lipids and autophagy-derived cargo such as dysfunctional proteins/organelles. We aimed to understand the effects of an atherogenic lipid environment on macrophage lysosomes and to evaluate novel ways to modulate this system. APPROACH AND RESULTS - Using a variety of complementary techniques, we show that oxidized low-density lipoproteins and cholesterol crystals, commonly encountered lipid species in atherosclerosis, lead to profound lysosomal dysfunction in cultured macrophages. Disruptions in lysosomal pH, proteolytic capacity, membrane integrity, and morphology are readily seen. Using flow cytometry, we find that macrophages isolated from atherosclerotic plaques also display features of lysosome dysfunction. We then investigated whether enhancing lysosomal function can be beneficial. Transcription factor EB (TFEB) is the only known transcription factor that is a master regulator of lysosomal biogenesis although its role in macrophages has not been studied. Lysosomal stress induced by chloroquine or atherogenic lipids leads to TFEB nuclear translocation and activation of lysosomal and autophagy genes. TFEB overexpression in macrophages further augments this prodegradative response and rescues several deleterious effects seen with atherogenic lipid loading as evidenced by blunted lysosomal dysfunction, reduced secretion of the proinflammatory cytokine interleukin-1β, enhanced cholesterol efflux, and decreased polyubiquitinated protein aggregation. CONCLUSIONS - Taken together, these data demonstrate that lysosomal function is markedly impaired in atherosclerosis and suggest that induction of a lysosomal biogenesis program in macrophages has antiatherogenic effects. © 2014 American Heart Association, Inc.
Klein A.J.,John Cochran Medical Center |
Pinto D.S.,Beth Israel Deaconess Medical Center |
Gray B.H.,University of South Carolina |
Jaff M.R.,Harvard University |
And 2 more authors.
Catheterization and Cardiovascular Interventions | Year: 2014
Successful endovascular intervention for femoral-popliteal (FP) arterial disease provides relief of claudication and offers limb-salvage in cases of critical limb ischemia. Technologies and operator technique have evolved to the point where we may now provide effective endovascular therapy for a spectrum of lesions, patients, and clinical scenarios. Endovascular treatment of this segment offers a significant alternative to surgical revascularization, and may confer improved safety for a wide range of patients, not solely those deemed high surgical risk. Although endovascular therapy of the FP segment has historically been hampered by high rates of restenosis, emerging technologies including drug-eluting stents, drug-coated balloons, and perhaps bio-absorbable stent platforms, provide future hope for more durable patency in complex disease. By combining lessons learned from clinical trials, international trends in clinical practice, and insights regarding emerging technologies, we may appropriately tailor our application of endovascular therapy to provide optimal care to our patients. This document was developed to guide physicians in the clinical decision-making related to the contemporary application of endovascular intervention among patients with FP arterial disease. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.
Xiucui M.,University of Washington |
Xiucui M.,John Cochran Medical Center |
Godar R.J.,University of Washington |
Godar R.J.,John Cochran Medical Center |
And 3 more authors.
Autophagy | Year: 2012
Hypoxia-inducible pro-death protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3), provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of autophagy accelerates BNIP3-induced cell death, by preventing removal of damaged mitochondria. We tested the hypothesis that stimulating autophagy will attenuate BNIP3-induced cardiomyocyte death. Neonatal rat cardiac myocytes (NRCMs) were adenovirally transduced with BNIP3 (or LacZ as control; at multiplicity of infection = 100); and autophagy was stimulated with rapamycin (100 nM). Cell death was assessed at 48 h. BNIP3 expression increased autophagosome abundance 8-fold and caused a 3.6-fold increase in cardiomyocyte death as compared with control. Rapamycin treatment of BNIP3-expressing cells led to further increase in autophagosome number without affecting cell death. BNIP3 expression led to accumulation of autophagosome-bound LC3-II and p62, and an increase in autophagosomes, but not autolysosomes (assessed with dual fluorescent mCherry-GFP-LC3 expression). BNIP3, but not the transmembrane deletion variant, interacted with LC3 and colocalized with mitochondria and lysosomes. However, BNIP3 did not target to lysosomes by subcellular fractionation, provoke lysosome permeabilization or alter lysosome pH. Rather, BNIP3-induced autophagy caused a decline in lysosome numbers with decreased expression of the lysosomal protein LAMP-1, indicating lysosome consumption and consequent autophagosome accumulation. Forced expression of transcription factor EB (TFEB) in BNIP3-expressing cells increased lysosome numbers, decreased autophagosomes and increased autolysosomes, prevented p62 accumulation, removed depolarized mitochondria and attenuated BNIP3-induced death. We conclude that BNIP3 expression induced autophagosome accumulation with lysosome consumption in cardiomyocytes. Forced expression of TFEB, a lysosomal biogenesis factor, restored autophagosome processing and attenuated BNIP3-induced cell death. © 2012 Landes Bioscience.
Ma X.,University of Washington |
Ma X.,John Cochran Medical Center |
Liu H.,University of Washington |
Foyil S.R.,University of Washington |
And 6 more authors.
Circulation | Year: 2012
Background-In myocardial ischemia, induction of autophagy via the AMP-induced protein kinase pathway is protective, whereas reperfusion stimulates autophagy with BECLIN-1 upregulation and is implicated in causing cell death. We examined flux through the macroautophagy pathway as a determinant of the discrepant outcomes in cardiomyocyte cell death in this setting. Methods and Results-Reversible left anterior descending coronary artery ligation was performed in mice with cardiomyocyte-restricted expression of green fluorescent protein-tagged microtubule-associated protein light chain-3 to induce ischemia (120 minutes) or ischemia/reperfusion (30-90 minutes) with saline or chloroquine pretreatment (n=4 per group). Autophagosome clearance, assessed as the ratio of punctate light chain-3 abundance in saline to chloroquine-treated samples, was markedly impaired with ischemia/reperfusion compared with sham controls. Reoxygenation increased cell death in neonatal rat cardiomyocytes compared with hypoxia alone, markedly increased autophagosomes but not autolysosomes (assessed as punctate dual fluorescent mCherry-green fluorescent protein tandem-tagged light chain-3 expression), and impaired clearance of polyglutamine aggregates, indicating impaired autophagic flux. The resultant autophagosome accumulation was associated with increased reactive oxygen species and mitochondrial permeabilization, leading to cell death, which was attenuated by cyclosporine A pretreatment. Hypoxia-reoxygenation injury was accompanied by reactive oxygen species-mediated BECLIN-1 upregulation and a reduction in lysosome-associated membrane protein-2, a critical determinant of autophagosome-lysosome fusion. Restoration of lysosome-associated membrane protein-2 levels synergizes with partial BECLIN-1 knockdown to restore autophagosome processing and to attenuate cell death after hypoxia-reoxygenation. Conclusion-Ischemia/reperfusion injury impairs autophagosome clearance mediated in part by reactive oxygen species-induced decline in lysosome-associated membrane protein-2 and upregulation of BECLIN-1, contributing to increased cardiomyocyte death. © 2012 American Heart Association, Inc.
Onken M.D.,University of Washington |
Winkler A.E.,University of Washington |
Kanchi K.-L.,University of Washington |
Chalivendra V.,University of Washington |
And 10 more authors.
Clinical Cancer Research | Year: 2014
Purpose: Improved understanding of the molecular basis underlying oral squamous cell carcinoma (OSCC) aggressive growth has significant clinical implications. Herein, cross-species genomic comparison of carcinogen-induced murine and human OSCCs with indolent or metastatic growth yielded results with surprising translational relevance. Experimental Design: Murine OSCC cell lines were subjected to next-generation sequencing (NGS) to define their mutational landscape, to define novel candidate cancer genes, and to assess for parallels with known drivers in human OSCC. Expression arrays identified a mouse metastasis signature, and we assessed its representation in four independent human datasets comprising 324 patients using weighted voting and gene set enrichment analysis. Kaplan-Meier analysis and multivariate Cox proportional hazards modeling were used to stratify outcomes. A quantitative real-time PCR assay based on the mouse signature coupled to a machine-learning algorithm was developed and used to stratify an independent set of 31 patients with respect to metastatic lymphadenopathy. Results: NGS revealed conservation of human driver pathway mutations in mouse OSCC, including in Trp53, mitogen-activated protein kinase, phosphoinositide 3-kinase, NOTCH, JAK/STAT, and Fat1-4. Moreover, comparative analysis between The Cancer Genome Atlas and mouse samples defined AKAP9, MED12L , and MYH6 as novel putative cancer genes. Expression analysis identified a transcriptional signature predicting aggressiveness and clinical outcomes, which were validated in four independent human OSCC datasets. Finally, we harnessed the translational potential of this signature by creating a clinically feasible assay that stratified patients with OSCC with a 93.5% accuracy. Conclusions: These data demonstrate surprising cross-species genomic conservation that has translational relevance for human oral squamous cell cancer. ©2014 AACR.
Yang K.-C.,Center for Cardiovascular Research |
Ma X.,Center for Cardiovascular Research |
Ma X.,John Cochran Medical Center |
Liu H.,Center for Cardiovascular Research |
And 8 more authors.
Circulation: Heart Failure | Year: 2015
Background-Tumor necrosis factor (TNF) signaling protects against ischemia/reperfusioninduced cardiomyocyte death, in vitro, ex vivo, and in vivo. TNF-receptorassociated factor 2 (TRAF2), an E3 ubiquitin ligase, coordinates cytoprotective signaling downstream of both TNF receptors, via unclear mechanisms. Noting that TRAF2 is recruited to mitochondria, and that autophagic removal of ubiquitin-tagged damaged mitochondria is cytoprotective, we tested the hypothesis that TRAF2 mediates mitochondrial autophagy. Methods and Results-TRAF2 localizes to the mitochondria in neonatal rat cardiac myocytes, and TNF treatment transcriptionally upregulates TRAF2 abundance in the mitochondrial subfraction. TRAF2 colocalizes with ubiquitin, p62 adaptor protein, and mitochondria within LC3-bound autophagosomes; and exogenous TRAF2 enhances autophagic removal of mitochondria. TRAF2 knockdown with adenoviral shRNA transduction induces accumulation of depolarized mitochondria in resting neonatal rat cardiac myocytes, as well as in those treated with TNF or uncoupling agent carbonyl cyanide m-chlorophenyl hydrazone, suggesting an essential role for TRAF2 in homeostatic and stress-induced mitochondrial autophagy. TRAF2 also colocalizes and interacts with PARKIN, a previously described E3 ubiquitin ligase and mitophagy effector, on depolarized mitochondria in neonatal rat cardiac myocytes. Exogenous expression of TRAF2, but not its E3 ligase-deficient mutants, is sufficient to partially restore mitophagy in the setting of PARKIN knockdown, suggesting redundancy in their ubiquitin ligase roles. TRAF2 abundance increases in the mitochondrial subfraction of ischemia/reperfusionmodeled hearts; and exogenous TRAF2, but not its E3 ligase-deficient mutants, reduces depolarized mitochondria and rescues cell death in neonatal rat cardiac myocytes subjected to hypoxia/reoxygenation. Conclusions-Taken together, these data indicate an essential role for TRAF2 in concert with PARKIN as a mitophagy effector, which contributes to TRAF2-induced cytoprotective signaling. © 2015 American Heart Association, Inc.
Kramer J.R.,Houston VA Health Services Research and 38 |
Kramer J.R.,Baylor College of Medicine |
Hachem C.Y.,Saint Louis University |
Kanwal F.,John Cochran Medical Center |
And 5 more authors.
Hepatology | Year: 2011
Coinfection with hepatitis A virus (HAV) or hepatitis B virus (HBV) in patients with chronic hepatitis C virus (HCV) is associated with increased morbidity and mortality. The Center for Medicare and Medicaid Services has identified HAV and HBV vaccination as a priority area for quality measurement in HCV. It is unclear to what extent patients with HCV meet these recommendations. We used national data from the Department of Veterans Affairs HCV Clinical Case Registry to evaluate the prevalence and predictors of meeting the quality measure (QM) of receiving vaccination or documented immunity to HAV and HBV in patients with chronic HCV. We identified 88,456 patients who had overall vaccination rates of 21.9% and 20.7% for HBV and HAV, respectively. The QM rates were 57.0% and 45.5% for HBV and HAV, respectively. Patients who were nonwhite or who had elevated alanine aminotransferase levels, cirrhosis, or human immunodeficiency virus were more likely to meet the HBV QM. Factors related to HCV care were also determinants of meeting the HBV QM. These factors included receiving a specialist consult, genotype testing, or HCV treatment. Patients who were older, had psychosis, and had a higher comorbidity score were less likely to meet the HBV QM. With a few exceptions, similar variables were related to meeting the HAV QM. The incidence of superinfection with acute HBV and HAV was low, but it was significantly lower in patients who received vaccination than in those who did not. Conclusion: Quality measure rates for HAV and HBV are suboptimal for patients with chronic HCV. In addition, several patient-related factors and receiving HCV-related care are associated with a higher likelihood of meeting QMs. © 2010 American Association for the Study of Liver Diseases.
Gandillon R.,John Cochran Medical Center
Journal of Clinical Engineering | Year: 2013
Through recent efforts aimed toward standardization of nomenclature for medical devices, the Veteran's Health Administration is now able to leverage a large set of equipment histories to investigate the reliability and usability of particular devices. This type of analysis led to the realization of obvious distinctions between the 4 major manufacturers of infusion pumps, both in failure and use error rates. More importantly, cost and time burdens associated with these failures and errors were calculated, and these numbers show the possible savings associated with using reliability and usability data as a contributing factor in medical equipment acquisitions. Copyright © 2013 Lippincott Williams & Wilkins.