Permissions: Requests for permissions to reproduce figures, tables, or portions of articles origi... more Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Arteriosclerosis, Thrombosis, and Vascular Biology can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at:
Activation of the Hippo pathway effector Yap underlies many liver cancers, however no germline or... more Activation of the Hippo pathway effector Yap underlies many liver cancers, however no germline or somatic mutations have been identified. Autophagy maintains essential metabolic functions of the liver, and autophagy-deficient murine models develop benign adenomas and hepatomegaly, which have been attributed to activation of the p62/Sqstm1-Nrf2 axis. Here, we show that Yap is an autophagy substrate and mediator of tissue remodeling and hepatocarcinogenesis independent of the p62/Sqstm1-Nrf2 axis. Hepatocyte-specific deletion of Atg7 promotes liver size, fibrosis, progenitor cell expansion, and hepatocarcinogenesis, which is rescued by concurrent deletion of Yap. Our results shed new light on mechanisms of Yap degradation and the sequence of events that follow disruption of autophagy, which is impaired in chronic liver disease.
Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome i... more Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome integrity in eukaryotic cells. However, their functional roles in cancer remain poorly understood. We interrogated the evolutionary transcriptomic landscape of NPC components, nucleoporins (Nups), from primary to advanced metastatic human prostate cancer (PC). Focused loss-of-function genetic screen of top-upregulated Nups in aggressive PC models identified POM121 as a key contributor to PC aggressiveness. Mechanistically, POM121 promoted PC progression by enhancing importin-dependent nuclear transport of key oncogenic (E2F1, MYC) and PC-specific (AR-GATA2) transcription factors, uncovering a pharmacologically targetable axis that, when inhibited, decreased tumor growth, restored standard therapy efficacy, and improved survival in patient-derived pre-clinical models. Our studies molecularly establish a role of NPCs in PC progression and give a rationale for NPC-regulated nuclear import ta...
Virological synapses (VS) are adhesive structures that form between infected and uninfected cells... more Virological synapses (VS) are adhesive structures that form between infected and uninfected cells to enhance the spread of HIV-1. During T cell VS formation, viral proteins are actively recruited to the site of cell-cell contact where the viral material is efficiently translocated to target cells into heterogeneous, protease-resistant, antibody-inaccessible compartments. Using correlative light and electron microscopy (CLEM), we define the membrane topography of the virus-containing compartments (VCC) where HIV is found following VS-mediated transfer. Focused ion beam scanning electron microscopy (FIB-SEM) and serial sectioning transmission electron microscopy (SS-TEM) were used to better resolve the fluorescent Gag-containing structures within the VCC. We found that small punctate fluorescent signals correlated with single viral particles in enclosed vesicular compartments or surface-localized virus particles and that large fluorescent signals correlated with membranous Gag-contain...
Cardiac toxicity is a major limitation in the use of doxorubicin (and related anthracyclins). ON ... more Cardiac toxicity is a major limitation in the use of doxorubicin (and related anthracyclins). ON 1910.Na (Estybon, Rogersitib, or 1910), a substituted benzyl styryl sulfone, is equally active as doxorubicin against MCF-7 human mammary carcinoma xenografted into nude mice. 1910 augments the antitumor activity of doxorubicin when given simultaneously. Furthermore, when given in combination, 1910 protects against cardiac weight loss and against morphological damage to cardiac tissues. Doxorubicin induces inactivation of glucose response protein 78 (GRP78), a principal chaperone that serves as the master regulator of the unfolded protein response (UPR). Inactivated GRP78 leads to an increase in misfolded proteins, endoplasmic reticulum (ER) stress, activation of UPR sensors, and increased CHOP expression. 1910 prevents the inactivation of GRP78 by doxorubicin, and the combination, while more active against the tumor, protects against cardiac weight loss.
We describe the first case of a patient with familial paragangliomas, acute postoperative catecho... more We describe the first case of a patient with familial paragangliomas, acute postoperative catecholamine-induced cardiomyopathy, and the subsequent diagnosis of an unsuspected adrenal pheochromocytoma. Relevant literature is reviewed, and treatment options are discussed.
Proceedings of the National Academy of Sciences, 2014
Significance This study shows that an endothelialized microfluidic chip with controllable permeab... more Significance This study shows that an endothelialized microfluidic chip with controllable permeability can serve as a model for nanoparticle translocation across the permeable endothelium. Integration of this in vitro model and an in vivo rabbit model revealed that the extravasation of nanoparticles across the endothelium in atherosclerotic plaques depends on microvascular permeability. This approach represents a unique method for the assessment of nanoparticle behavior across the atherosclerotic endothelium, and may also serve as a valuable tool to study nanomedicine accumulation in a variety of other diseases.
High density lipoprotein (HDL), is an important natural nanoparticle that may be modified for bio... more High density lipoprotein (HDL), is an important natural nanoparticle that may be modified for biomedical imaging purposes. Here we developed a novel technique to create unique multimodality HDL mimicking nanoparticles by inclusion of gold, iron oxide or quantum dot nanocrystals for computed tomography, magnetic resonance and fluorescence imaging, respectively. By including additional labels in the corona of the particles, they were made multi-functional. The characterization of these nanoparticles, as well as their in vitro and in vivo behavior revealed that they closely mimic native HDL.
Acute intermittent porphyria (AIP) is an autosomal-dominant condition resulting from a partial de... more Acute intermittent porphyria (AIP) is an autosomal-dominant condition resulting from a partial deficiency of the ubiquitously expressed enzyme porphobilinogen deaminase. Although its clinical expression is highly variable, a minority of patients suffer recurrent life-threatening neurovisceral attacks despite optimal medical therapy. Because the liver is the major source of excess precursor production, liver transplantation (LT) represents a potentially effective treatment for severely affected patients. Using data from the UK Transplant Registry, we analyzed all transplants performed for AIP in the United Kingdom and Ireland. Between 2002 and 2010, 10 patients underwent LT for AIP. In all cases, the indication for transplantation was recurrent, biochemically proven, medically nonresponsive acute attacks of porphyria resulting in significantly impaired quality of life. Five patients had developed significant neurological morbidities such as paraplegia before transplantation. The median follow-up time was 23.4 months, and there were 2 deaths from multiorgan failure at 98 days and 26 months. Eight recipients were alive for 3.2 to 109 months after transplantation. Complete biochemical and symptomatic resolution was observed in all patients after transplantation. However, there was a high rate of hepatic artery thrombosis (HAT; 4/10), with 1 patient requiring regrafting. The effects of previous neuronal damage such as joint contractures were not improved by transplantation. Thus, impaired quality of life in the surviving patients was usually a result of preoperative complications. Refractory AIP is an excellent indication for LT, and long-term outcomes for carefully selected patients are good. There is, however, an increased incidence of HAT in these patients, and we recommend routine antiplatelet therapy after transplantation.
Types A and B Niemann-Pick disease (NPD) are lipid storage diseases caused by the deficient activ... more Types A and B Niemann-Pick disease (NPD) are lipid storage diseases caused by the deficient activity of the lysosomal enzyme, acid sphingomyelinase (ASM). Type B NPD is associated with progressive pulmonary function decline and frequent respiratory infections. ASM knockout (ASMKO) mice are available as a model for NPD, but the lung pathology in these mice has not been adequately characterized. This study shows that by 10 weeks of age ASMKO mice have a significantly higher number of cells in their pulmonary airspaces than normal mice, consisting primarily of enlarged and often multinucleated macrophages. These mice also have much higher levels of sphingomyelin in their airspaces at 10 weeks of age, and both cell numbers and sphingomyelin concentrations remain elevated until 26 weeks of age. In these older mice an increased number of neutrophils is also seen. The alveolar cell population in the ASMKO mice produces less superoxide when stimulated, but this can be corrected by providing recombinant ASM to the culture media. Elevated levels of the chemokines macrophage inflammatory protein-2 and macrophage inflammatory protein-1␣ were also present in the bronchoalveolar lavage fluid of ASMKO mice, and this correlated with increased production of these chemokines by cultured macrophages and enhanced immunostaining in situ. Also, lung histology showed increased cellularity in the alveolar walls of ASMKO mice, but no evidence of fibrosis. Ultrastructural analysis of the lungs showed that the ASMKO mice have similar pathologic features to human NPD patients, with variable lipid storage evident in type I pneumocytes, endothelial cells, and airway ciliated epithelia. The alveolar macrophage, however, was the most dramatically affected cell type in both mice and humans. These studies indicate that the ASMKO mice can be used as a model to study the lung pathology associated with NPD, and demonstrate that the cellular and biochemical analysis of pulmonary airspaces may be a useful approach to monitoring disease progression and/or treatment.
The assembly of infectious human immunodeficiency virus (HIV) requires that Gag transport and oli... more The assembly of infectious human immunodeficiency virus (HIV) requires that Gag transport and oligomerization be coordinated with its association with other viral proteins, viral RNAs, and cellular membranes. We have developed a replication-competent HIV type 1 molecular clone that carries a Gag-internal or interdomain green fluorescent protein (iGFP) fusion to reveal a physiologically accurate temporal sequence of Gag localization and oligomerization during the formation of infectious HIV. This recombinant HIV is as infectious as native HIV in single-round infectivity assays, validating its use for trafficking studies. It replicates robustly in permissive MT4 cells and is infectious, yet it spreads poorly in other T-cell lines. Immunofluorescence of Gag-iGFP showed a pattern very similar to that of native Gag. However, the intense plasma membrane Gag-iGFP fluorescence contrasts markedly with its immunofluorescence at this site, indicating that many Gag epitopes can be masked by oli...
Journal of the American College of Cardiology, 2002
OBJECTIVES This study was designed to assess the effect of abciximab on platelet and leukocyte de... more OBJECTIVES This study was designed to assess the effect of abciximab on platelet and leukocyte deposition 60 min after stent insertion in nonhuman primates. BACKGROUND Although it is well established that abciximab improves both short-and long-term clinical outcomes after stent placement, there have been no studies assessing its effect on early platelet and leukocyte deposition. METHODS Cynomolgus monkeys were pretreated with aspirin and either saline or a 0.4 mg/kg bolus of abciximab, and then subjected to angioplasty and Palmaz-Schatz stent placement in the common iliac artery or abdominal aorta. After 60 min, animals were euthanized and the stented artery was evaluated by immunohistochemistry and morphometry. RESULTS Complete occlusion of the stented vessel with a thin fibrin(ogen) meshwork and trapped blood occurred in two saline-treated and two abciximab-treated animals. In the four remaining saline-treated animals, a layer of erythrocytes trapped in a network of fibrin(ogen) was noted close to the vessel wall, and this was covered by a layer of large, irregular platelet thrombi. Leukocytes formed a monolayer on top of the platelets and near stent struts. In the four remaining abciximab-treated animals, the mean erythrocyte area was 65% smaller (p ϭ 0.070), the platelet aggregate area was 89% smaller (p ϭ 0.049) and the luminal area was 59% larger (p ϭ 0.004). A monolayer of leukocytes also formed on top of the platelets and near stent struts. CONCLUSIONS In control stented blood vessels in this study, platelet thrombi formed not at the vessel wall, but on top of an erythrocyte-rich layer, and platelets recruited leukocytes. Abciximab decreased the size of platelet thrombi, but did not prevent leukocyte recruitment.
Background— In classic Fabry patients, accelerated coronary atherosclerosis and left ventricular ... more Background— In classic Fabry patients, accelerated coronary atherosclerosis and left ventricular hypertrophy manifest in the fourth decade; however, signs of cardiovascular disease also are observed later in life in “cardiac variant” patients and symptomatic female heterozygotes. These disturbances are caused by globotriaosylceramide (GL-3) accumulation in the heart resulting from lysosomal α-galactosidase A deficiency. Methods and Results— We analyzed pretreatment and posttreatment endomyocardial biopsies from 58 Fabry patients enrolled in a 5-month, phase 3, double-blind, randomized, placebo-controlled trial, followed by a 54-month open-label extension study of recombinant human α-galactosidase A. Baseline evaluations revealed GL-3 deposits in interstitial capillary endothelial cells and large, laminated inclusions within cardiomyocytes. In this study, we evaluated microvascular GL-3 clearance; no clearance of GL-3 was observed in the cardiomyocytes during this trial. Five months ...
Background —Intimal hyperplasia contributes to restenosis after percutaneous vascular interventio... more Background —Intimal hyperplasia contributes to restenosis after percutaneous vascular interventions. Both β 3 -integrins, α V β 3 and α IIb β 3 (glycoprotein IIb/IIIa), and leukocytes have been implicated in neointimal formation, based in part on the results obtained using antagonists to 1 or both receptors in animal models. Methods and Results —The responses in wild-type mice, β 3 -integrin–deficient mice, and P-selectin–deficient mice were studied in a model of transluminal endothelial injury of the femoral artery. At 4 weeks, β 3 -integrin–deficient mice were not protected from developing intimal hyperplasia, whereas P-selectin–deficient mice were protected. Within 1 hour of injury, several layers of platelets deposited on the arteries of wild-type mice and a single layer of platelets deposited on the vessels of β 3 -integrin–deficient mice; in both cases, leukocytes were recruited to the platelet layer. In P-selectin–deficient mice, the platelet layer was less compact and extend...
Arteriosclerosis, Thrombosis, and Vascular Biology, 2003
Objective— A diabetic mouse model of accelerated neointimal formation would be a useful tool to u... more Objective— A diabetic mouse model of accelerated neointimal formation would be a useful tool to understand the increased incidence of restenosis in patients with diabetes. Methods and Results— Femoral artery endoluminal wire injury was performed in diabetic insulin 2 Akita ( ins2 Akita ) and leptin receptor db/db ( lepr db/db ) mutant mice. Neointima size in ins2 Akita mouse arteries was unchanged compared with nondiabetic wild-type littermates. Although Ki67 labeling demonstrated similar rates of replication in the neointima of lepr db/db mouse arteries, neointimal formation in lepr db/db mice was surprisingly reduced by ≈90% compared with nondiabetic lepr +/+ mice. Four hours after arterial injury, medial smooth muscle cell death was diminished in lepr db/db arteries, suggesting that the initial response to arterial injury was altered in lepr db/db mice. Conclusions— These studies highlight a differential response to arterial injury in lepr db/db mice and suggest a potential role ...
Acid sphingomyelinase knockout mice are a model of the inherited human disorder types A and B Nie... more Acid sphingomyelinase knockout mice are a model of the inherited human disorder types A and B Niemann-Pick disease. Herein , we show that heterozygous (ASMKO ؉/؊) mice have two distinct sperm populations resembling those found in normal and mutant animals , respectively , and that these two populations could be distinguished by their morphology , ability to undergo capacitation or the acrosome reaction, and/or mitochondrial membrane potential (MMP). The abnormal morphology of the mutant sperm could be normalized by demembranation with detergents or by the addition of recombinant acid sphingomyelinase to the culture media , and the corrected sperm also had an enhanced fertilization capacity. Methods were then explored to enrich for normal sperm from the mixed ASMKO ؉/؊ population, and flow cytometric sorting based on MMP provided the best results. In vitro fertilization was performed using ASMKO ؉/؊ oocytes and sperm before and after MMP sorting , and it was found that the sorted sperm produced significantly more wild-type pups than nonsorted sperm. Sperm sorting is much less invasive and more cost-effective than egg isolation, and offers several advantages over the existing assisted reproduction options for Niemann-Pick disease carrier couples. It therefore could have a major impact on the prevention of this and perhaps other genetic diseases.
There are many liver diseases that could be treated with delivery of therapeutics such as DNA, pr... more There are many liver diseases that could be treated with delivery of therapeutics such as DNA, proteins or small molecules. Nanoparticles are often proposed as delivery vectors for such therapeutics, however, achieving nanoparticle accumulations in the therapeutically relevant hepatocytes is challenging. In order to address this issue, we have synthesized polymer coated, fluorescent iron oxide nanoparticles that bind and deliver DNA, as well as produce contrast for magnetic resonance imaging (MRI), fluorescence imaging and transmission electron microscopy (TEM). The composition of the coating can be varied in a facile manner to increase the quantity of polyethylene glycol (PEG) from 0% to 5%, 10% or 25%, with the aim of reducing opsonization, but maintaining DNA binding. We investigated the effect of the nanoparticle coating on DNA binding, cell uptake, cell transfection and opsonization in vitro. Furthermore, we exploited MRI, fluorescence imaging and TEM to investigate the distribution of the different formulations in the liver of mice. While MRI and fluorescence imaging showed that each formulation was heavily taken up in the livers at 24 hours, the 10% PEG formulation was taken up by the therapeutically relevant hepatocytes more extensively than either the 0% PEG or the 5% PEG, indicating its potential for delivery of therapeutics to the liver.
Atherosclerosis is a major cause of global morbidity and mortality that could benefit from novel ... more Atherosclerosis is a major cause of global morbidity and mortality that could benefit from novel targeted therapeutics. Recent studies have shown efficient and local drug delivery with nanoparticles, although the nanoparticle targeting mechanism for atherosclerosis has not yet been fully elucidated. Here we used in vivo and ex vivo multimodal imaging to examine permeability of the vessel wall and atherosclerotic plaque accumulation of fluorescently labeled liposomal nanoparticles in a rabbit model. We found a strong correlation between permeability as established by in vivo dynamic contrast enhanced magnetic resonance imaging and nanoparticle plaque accumulation with subsequent nanoparticle distribution throughout the vessel wall. These key observations will enable the development of nanotherapeutic strategies for atherosclerosis.
Fabry disease results from deficient a-galactosidase A (a-Gal A) activity and the pathologic accu... more Fabry disease results from deficient a-galactosidase A (a-Gal A) activity and the pathologic accumulation of the globotriaosylceramide (GL-3) and related glycosphingolipids, primarily in vascular endothelial lysosomes. Treatment is currently palliative, and affected patients generally die in their 40s or 50s. Preclinical studies of recombinant human a-Gal A (r-haGalA) infusions in knockout mice demonstrated reduction of GL-3 in tissues and plasma, providing rationale for a phase 1/2 clinical trial. Here, we report a single-center, open-label, dose-ranging study of r-haGalA treatment in 15 patients, each of whom received five infusions at one of five dose regimens. Intravenously administered r-haGalA was cleared from the circulation in a dose-dependent manner, via both saturable and nonsaturable pathways. Rapid and marked reductions in plasma and tissue GL-3 were observed biochemically, histologically, and/or ultrastructurally. Clearance of plasma GL-3 was dose-dependent. In patients with pre-and posttreatment biopsies, mean GL-3 content decreased 84% in liver (), was markedly reduced in kidney in n p 13 four of five patients, and after five doses was modestly lowered in the endomyocardium of four of seven patients. GL-3 deposits were cleared to near normal or were markedly reduced in the vascular endothelium of liver, skin, heart, and kidney, on the basis of light-and electron-microscopic evaluation. In addition, patients reported less pain, increased ability to sweat, and improved quality-of-life measures. Infusions were well tolerated; four patients experienced mild-to-moderate reactions, suggestive of hypersensitivity, that were managed conservatively. Of 15 patients, 8 (53%) developed IgG antibodies to r-haGalA; however, the antibodies were not neutralizing, as indicated by unchanged pharmacokinetic values for infusions 1 and 5. This study provides the basis for a phase 3 trial of enzyme-replacement therapy for Fabry disease.
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles origi... more Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Arteriosclerosis, Thrombosis, and Vascular Biology can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at:
Activation of the Hippo pathway effector Yap underlies many liver cancers, however no germline or... more Activation of the Hippo pathway effector Yap underlies many liver cancers, however no germline or somatic mutations have been identified. Autophagy maintains essential metabolic functions of the liver, and autophagy-deficient murine models develop benign adenomas and hepatomegaly, which have been attributed to activation of the p62/Sqstm1-Nrf2 axis. Here, we show that Yap is an autophagy substrate and mediator of tissue remodeling and hepatocarcinogenesis independent of the p62/Sqstm1-Nrf2 axis. Hepatocyte-specific deletion of Atg7 promotes liver size, fibrosis, progenitor cell expansion, and hepatocarcinogenesis, which is rescued by concurrent deletion of Yap. Our results shed new light on mechanisms of Yap degradation and the sequence of events that follow disruption of autophagy, which is impaired in chronic liver disease.
Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome i... more Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome integrity in eukaryotic cells. However, their functional roles in cancer remain poorly understood. We interrogated the evolutionary transcriptomic landscape of NPC components, nucleoporins (Nups), from primary to advanced metastatic human prostate cancer (PC). Focused loss-of-function genetic screen of top-upregulated Nups in aggressive PC models identified POM121 as a key contributor to PC aggressiveness. Mechanistically, POM121 promoted PC progression by enhancing importin-dependent nuclear transport of key oncogenic (E2F1, MYC) and PC-specific (AR-GATA2) transcription factors, uncovering a pharmacologically targetable axis that, when inhibited, decreased tumor growth, restored standard therapy efficacy, and improved survival in patient-derived pre-clinical models. Our studies molecularly establish a role of NPCs in PC progression and give a rationale for NPC-regulated nuclear import ta...
Virological synapses (VS) are adhesive structures that form between infected and uninfected cells... more Virological synapses (VS) are adhesive structures that form between infected and uninfected cells to enhance the spread of HIV-1. During T cell VS formation, viral proteins are actively recruited to the site of cell-cell contact where the viral material is efficiently translocated to target cells into heterogeneous, protease-resistant, antibody-inaccessible compartments. Using correlative light and electron microscopy (CLEM), we define the membrane topography of the virus-containing compartments (VCC) where HIV is found following VS-mediated transfer. Focused ion beam scanning electron microscopy (FIB-SEM) and serial sectioning transmission electron microscopy (SS-TEM) were used to better resolve the fluorescent Gag-containing structures within the VCC. We found that small punctate fluorescent signals correlated with single viral particles in enclosed vesicular compartments or surface-localized virus particles and that large fluorescent signals correlated with membranous Gag-contain...
Cardiac toxicity is a major limitation in the use of doxorubicin (and related anthracyclins). ON ... more Cardiac toxicity is a major limitation in the use of doxorubicin (and related anthracyclins). ON 1910.Na (Estybon, Rogersitib, or 1910), a substituted benzyl styryl sulfone, is equally active as doxorubicin against MCF-7 human mammary carcinoma xenografted into nude mice. 1910 augments the antitumor activity of doxorubicin when given simultaneously. Furthermore, when given in combination, 1910 protects against cardiac weight loss and against morphological damage to cardiac tissues. Doxorubicin induces inactivation of glucose response protein 78 (GRP78), a principal chaperone that serves as the master regulator of the unfolded protein response (UPR). Inactivated GRP78 leads to an increase in misfolded proteins, endoplasmic reticulum (ER) stress, activation of UPR sensors, and increased CHOP expression. 1910 prevents the inactivation of GRP78 by doxorubicin, and the combination, while more active against the tumor, protects against cardiac weight loss.
We describe the first case of a patient with familial paragangliomas, acute postoperative catecho... more We describe the first case of a patient with familial paragangliomas, acute postoperative catecholamine-induced cardiomyopathy, and the subsequent diagnosis of an unsuspected adrenal pheochromocytoma. Relevant literature is reviewed, and treatment options are discussed.
Proceedings of the National Academy of Sciences, 2014
Significance This study shows that an endothelialized microfluidic chip with controllable permeab... more Significance This study shows that an endothelialized microfluidic chip with controllable permeability can serve as a model for nanoparticle translocation across the permeable endothelium. Integration of this in vitro model and an in vivo rabbit model revealed that the extravasation of nanoparticles across the endothelium in atherosclerotic plaques depends on microvascular permeability. This approach represents a unique method for the assessment of nanoparticle behavior across the atherosclerotic endothelium, and may also serve as a valuable tool to study nanomedicine accumulation in a variety of other diseases.
High density lipoprotein (HDL), is an important natural nanoparticle that may be modified for bio... more High density lipoprotein (HDL), is an important natural nanoparticle that may be modified for biomedical imaging purposes. Here we developed a novel technique to create unique multimodality HDL mimicking nanoparticles by inclusion of gold, iron oxide or quantum dot nanocrystals for computed tomography, magnetic resonance and fluorescence imaging, respectively. By including additional labels in the corona of the particles, they were made multi-functional. The characterization of these nanoparticles, as well as their in vitro and in vivo behavior revealed that they closely mimic native HDL.
Acute intermittent porphyria (AIP) is an autosomal-dominant condition resulting from a partial de... more Acute intermittent porphyria (AIP) is an autosomal-dominant condition resulting from a partial deficiency of the ubiquitously expressed enzyme porphobilinogen deaminase. Although its clinical expression is highly variable, a minority of patients suffer recurrent life-threatening neurovisceral attacks despite optimal medical therapy. Because the liver is the major source of excess precursor production, liver transplantation (LT) represents a potentially effective treatment for severely affected patients. Using data from the UK Transplant Registry, we analyzed all transplants performed for AIP in the United Kingdom and Ireland. Between 2002 and 2010, 10 patients underwent LT for AIP. In all cases, the indication for transplantation was recurrent, biochemically proven, medically nonresponsive acute attacks of porphyria resulting in significantly impaired quality of life. Five patients had developed significant neurological morbidities such as paraplegia before transplantation. The median follow-up time was 23.4 months, and there were 2 deaths from multiorgan failure at 98 days and 26 months. Eight recipients were alive for 3.2 to 109 months after transplantation. Complete biochemical and symptomatic resolution was observed in all patients after transplantation. However, there was a high rate of hepatic artery thrombosis (HAT; 4/10), with 1 patient requiring regrafting. The effects of previous neuronal damage such as joint contractures were not improved by transplantation. Thus, impaired quality of life in the surviving patients was usually a result of preoperative complications. Refractory AIP is an excellent indication for LT, and long-term outcomes for carefully selected patients are good. There is, however, an increased incidence of HAT in these patients, and we recommend routine antiplatelet therapy after transplantation.
Types A and B Niemann-Pick disease (NPD) are lipid storage diseases caused by the deficient activ... more Types A and B Niemann-Pick disease (NPD) are lipid storage diseases caused by the deficient activity of the lysosomal enzyme, acid sphingomyelinase (ASM). Type B NPD is associated with progressive pulmonary function decline and frequent respiratory infections. ASM knockout (ASMKO) mice are available as a model for NPD, but the lung pathology in these mice has not been adequately characterized. This study shows that by 10 weeks of age ASMKO mice have a significantly higher number of cells in their pulmonary airspaces than normal mice, consisting primarily of enlarged and often multinucleated macrophages. These mice also have much higher levels of sphingomyelin in their airspaces at 10 weeks of age, and both cell numbers and sphingomyelin concentrations remain elevated until 26 weeks of age. In these older mice an increased number of neutrophils is also seen. The alveolar cell population in the ASMKO mice produces less superoxide when stimulated, but this can be corrected by providing recombinant ASM to the culture media. Elevated levels of the chemokines macrophage inflammatory protein-2 and macrophage inflammatory protein-1␣ were also present in the bronchoalveolar lavage fluid of ASMKO mice, and this correlated with increased production of these chemokines by cultured macrophages and enhanced immunostaining in situ. Also, lung histology showed increased cellularity in the alveolar walls of ASMKO mice, but no evidence of fibrosis. Ultrastructural analysis of the lungs showed that the ASMKO mice have similar pathologic features to human NPD patients, with variable lipid storage evident in type I pneumocytes, endothelial cells, and airway ciliated epithelia. The alveolar macrophage, however, was the most dramatically affected cell type in both mice and humans. These studies indicate that the ASMKO mice can be used as a model to study the lung pathology associated with NPD, and demonstrate that the cellular and biochemical analysis of pulmonary airspaces may be a useful approach to monitoring disease progression and/or treatment.
The assembly of infectious human immunodeficiency virus (HIV) requires that Gag transport and oli... more The assembly of infectious human immunodeficiency virus (HIV) requires that Gag transport and oligomerization be coordinated with its association with other viral proteins, viral RNAs, and cellular membranes. We have developed a replication-competent HIV type 1 molecular clone that carries a Gag-internal or interdomain green fluorescent protein (iGFP) fusion to reveal a physiologically accurate temporal sequence of Gag localization and oligomerization during the formation of infectious HIV. This recombinant HIV is as infectious as native HIV in single-round infectivity assays, validating its use for trafficking studies. It replicates robustly in permissive MT4 cells and is infectious, yet it spreads poorly in other T-cell lines. Immunofluorescence of Gag-iGFP showed a pattern very similar to that of native Gag. However, the intense plasma membrane Gag-iGFP fluorescence contrasts markedly with its immunofluorescence at this site, indicating that many Gag epitopes can be masked by oli...
Journal of the American College of Cardiology, 2002
OBJECTIVES This study was designed to assess the effect of abciximab on platelet and leukocyte de... more OBJECTIVES This study was designed to assess the effect of abciximab on platelet and leukocyte deposition 60 min after stent insertion in nonhuman primates. BACKGROUND Although it is well established that abciximab improves both short-and long-term clinical outcomes after stent placement, there have been no studies assessing its effect on early platelet and leukocyte deposition. METHODS Cynomolgus monkeys were pretreated with aspirin and either saline or a 0.4 mg/kg bolus of abciximab, and then subjected to angioplasty and Palmaz-Schatz stent placement in the common iliac artery or abdominal aorta. After 60 min, animals were euthanized and the stented artery was evaluated by immunohistochemistry and morphometry. RESULTS Complete occlusion of the stented vessel with a thin fibrin(ogen) meshwork and trapped blood occurred in two saline-treated and two abciximab-treated animals. In the four remaining saline-treated animals, a layer of erythrocytes trapped in a network of fibrin(ogen) was noted close to the vessel wall, and this was covered by a layer of large, irregular platelet thrombi. Leukocytes formed a monolayer on top of the platelets and near stent struts. In the four remaining abciximab-treated animals, the mean erythrocyte area was 65% smaller (p ϭ 0.070), the platelet aggregate area was 89% smaller (p ϭ 0.049) and the luminal area was 59% larger (p ϭ 0.004). A monolayer of leukocytes also formed on top of the platelets and near stent struts. CONCLUSIONS In control stented blood vessels in this study, platelet thrombi formed not at the vessel wall, but on top of an erythrocyte-rich layer, and platelets recruited leukocytes. Abciximab decreased the size of platelet thrombi, but did not prevent leukocyte recruitment.
Background— In classic Fabry patients, accelerated coronary atherosclerosis and left ventricular ... more Background— In classic Fabry patients, accelerated coronary atherosclerosis and left ventricular hypertrophy manifest in the fourth decade; however, signs of cardiovascular disease also are observed later in life in “cardiac variant” patients and symptomatic female heterozygotes. These disturbances are caused by globotriaosylceramide (GL-3) accumulation in the heart resulting from lysosomal α-galactosidase A deficiency. Methods and Results— We analyzed pretreatment and posttreatment endomyocardial biopsies from 58 Fabry patients enrolled in a 5-month, phase 3, double-blind, randomized, placebo-controlled trial, followed by a 54-month open-label extension study of recombinant human α-galactosidase A. Baseline evaluations revealed GL-3 deposits in interstitial capillary endothelial cells and large, laminated inclusions within cardiomyocytes. In this study, we evaluated microvascular GL-3 clearance; no clearance of GL-3 was observed in the cardiomyocytes during this trial. Five months ...
Background —Intimal hyperplasia contributes to restenosis after percutaneous vascular interventio... more Background —Intimal hyperplasia contributes to restenosis after percutaneous vascular interventions. Both β 3 -integrins, α V β 3 and α IIb β 3 (glycoprotein IIb/IIIa), and leukocytes have been implicated in neointimal formation, based in part on the results obtained using antagonists to 1 or both receptors in animal models. Methods and Results —The responses in wild-type mice, β 3 -integrin–deficient mice, and P-selectin–deficient mice were studied in a model of transluminal endothelial injury of the femoral artery. At 4 weeks, β 3 -integrin–deficient mice were not protected from developing intimal hyperplasia, whereas P-selectin–deficient mice were protected. Within 1 hour of injury, several layers of platelets deposited on the arteries of wild-type mice and a single layer of platelets deposited on the vessels of β 3 -integrin–deficient mice; in both cases, leukocytes were recruited to the platelet layer. In P-selectin–deficient mice, the platelet layer was less compact and extend...
Arteriosclerosis, Thrombosis, and Vascular Biology, 2003
Objective— A diabetic mouse model of accelerated neointimal formation would be a useful tool to u... more Objective— A diabetic mouse model of accelerated neointimal formation would be a useful tool to understand the increased incidence of restenosis in patients with diabetes. Methods and Results— Femoral artery endoluminal wire injury was performed in diabetic insulin 2 Akita ( ins2 Akita ) and leptin receptor db/db ( lepr db/db ) mutant mice. Neointima size in ins2 Akita mouse arteries was unchanged compared with nondiabetic wild-type littermates. Although Ki67 labeling demonstrated similar rates of replication in the neointima of lepr db/db mouse arteries, neointimal formation in lepr db/db mice was surprisingly reduced by ≈90% compared with nondiabetic lepr +/+ mice. Four hours after arterial injury, medial smooth muscle cell death was diminished in lepr db/db arteries, suggesting that the initial response to arterial injury was altered in lepr db/db mice. Conclusions— These studies highlight a differential response to arterial injury in lepr db/db mice and suggest a potential role ...
Acid sphingomyelinase knockout mice are a model of the inherited human disorder types A and B Nie... more Acid sphingomyelinase knockout mice are a model of the inherited human disorder types A and B Niemann-Pick disease. Herein , we show that heterozygous (ASMKO ؉/؊) mice have two distinct sperm populations resembling those found in normal and mutant animals , respectively , and that these two populations could be distinguished by their morphology , ability to undergo capacitation or the acrosome reaction, and/or mitochondrial membrane potential (MMP). The abnormal morphology of the mutant sperm could be normalized by demembranation with detergents or by the addition of recombinant acid sphingomyelinase to the culture media , and the corrected sperm also had an enhanced fertilization capacity. Methods were then explored to enrich for normal sperm from the mixed ASMKO ؉/؊ population, and flow cytometric sorting based on MMP provided the best results. In vitro fertilization was performed using ASMKO ؉/؊ oocytes and sperm before and after MMP sorting , and it was found that the sorted sperm produced significantly more wild-type pups than nonsorted sperm. Sperm sorting is much less invasive and more cost-effective than egg isolation, and offers several advantages over the existing assisted reproduction options for Niemann-Pick disease carrier couples. It therefore could have a major impact on the prevention of this and perhaps other genetic diseases.
There are many liver diseases that could be treated with delivery of therapeutics such as DNA, pr... more There are many liver diseases that could be treated with delivery of therapeutics such as DNA, proteins or small molecules. Nanoparticles are often proposed as delivery vectors for such therapeutics, however, achieving nanoparticle accumulations in the therapeutically relevant hepatocytes is challenging. In order to address this issue, we have synthesized polymer coated, fluorescent iron oxide nanoparticles that bind and deliver DNA, as well as produce contrast for magnetic resonance imaging (MRI), fluorescence imaging and transmission electron microscopy (TEM). The composition of the coating can be varied in a facile manner to increase the quantity of polyethylene glycol (PEG) from 0% to 5%, 10% or 25%, with the aim of reducing opsonization, but maintaining DNA binding. We investigated the effect of the nanoparticle coating on DNA binding, cell uptake, cell transfection and opsonization in vitro. Furthermore, we exploited MRI, fluorescence imaging and TEM to investigate the distribution of the different formulations in the liver of mice. While MRI and fluorescence imaging showed that each formulation was heavily taken up in the livers at 24 hours, the 10% PEG formulation was taken up by the therapeutically relevant hepatocytes more extensively than either the 0% PEG or the 5% PEG, indicating its potential for delivery of therapeutics to the liver.
Atherosclerosis is a major cause of global morbidity and mortality that could benefit from novel ... more Atherosclerosis is a major cause of global morbidity and mortality that could benefit from novel targeted therapeutics. Recent studies have shown efficient and local drug delivery with nanoparticles, although the nanoparticle targeting mechanism for atherosclerosis has not yet been fully elucidated. Here we used in vivo and ex vivo multimodal imaging to examine permeability of the vessel wall and atherosclerotic plaque accumulation of fluorescently labeled liposomal nanoparticles in a rabbit model. We found a strong correlation between permeability as established by in vivo dynamic contrast enhanced magnetic resonance imaging and nanoparticle plaque accumulation with subsequent nanoparticle distribution throughout the vessel wall. These key observations will enable the development of nanotherapeutic strategies for atherosclerosis.
Fabry disease results from deficient a-galactosidase A (a-Gal A) activity and the pathologic accu... more Fabry disease results from deficient a-galactosidase A (a-Gal A) activity and the pathologic accumulation of the globotriaosylceramide (GL-3) and related glycosphingolipids, primarily in vascular endothelial lysosomes. Treatment is currently palliative, and affected patients generally die in their 40s or 50s. Preclinical studies of recombinant human a-Gal A (r-haGalA) infusions in knockout mice demonstrated reduction of GL-3 in tissues and plasma, providing rationale for a phase 1/2 clinical trial. Here, we report a single-center, open-label, dose-ranging study of r-haGalA treatment in 15 patients, each of whom received five infusions at one of five dose regimens. Intravenously administered r-haGalA was cleared from the circulation in a dose-dependent manner, via both saturable and nonsaturable pathways. Rapid and marked reductions in plasma and tissue GL-3 were observed biochemically, histologically, and/or ultrastructurally. Clearance of plasma GL-3 was dose-dependent. In patients with pre-and posttreatment biopsies, mean GL-3 content decreased 84% in liver (), was markedly reduced in kidney in n p 13 four of five patients, and after five doses was modestly lowered in the endomyocardium of four of seven patients. GL-3 deposits were cleared to near normal or were markedly reduced in the vascular endothelium of liver, skin, heart, and kidney, on the basis of light-and electron-microscopic evaluation. In addition, patients reported less pain, increased ability to sweat, and improved quality-of-life measures. Infusions were well tolerated; four patients experienced mild-to-moderate reactions, suggestive of hypersensitivity, that were managed conservatively. Of 15 patients, 8 (53%) developed IgG antibodies to r-haGalA; however, the antibodies were not neutralizing, as indicated by unchanged pharmacokinetic values for infusions 1 and 5. This study provides the basis for a phase 3 trial of enzyme-replacement therapy for Fabry disease.
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Papers by Ronald Gordon