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1.  Induction of pluripotency in bone marrow mononuclear cells via polyketal nanoparticle-mediated delivery of mature microRNAs 
Biomaterials  2013;34(17):4235-4241.
Since the successful generation of induced pluripotent stem cells (iPSC) from adult somatic cells using integrating-viral methods, various methods have been tried for iPSC generation using non-viral and non-integrating technique for clinical applications. Recently, various non-viral approaches such as protein, mRNA, microRNA, and small molecule transduction were developed to avoid genomic integration and generate stem cell-like cells from mouse and human fibroblasts. Despite these successes, there has been no successful generation of iPSC from bone marrow (BM)-derived hematopoietic cells derived using non-viral methods to date. Previous reports demonstrate the ability of polymeric micro and nanoparticles made from polyketals to deliver various molecules to macrophages. MicroRNA-loaded nanoparticles were created using the olyketal polymer PK3 (PK3-miR) and delivered to somatic cells for 6 days, resulting in the formation of colonies. Isolated cells from these colonies were assayed and substantial induction of the pluripotency markers Oct4, Sox2, and Nanog were detected. Moreover, colonies transferred to feeder layers also stained positive for pluripotency markers including SSEA-1. Here, we demonstrate successful activation of pluripotency-associated genes in mouse BM-mononuclear cells using embryonic stem cell (ESC)-specific microRNAs encapsulated in the acid sensitive polyketal PK3. These reprogramming results demonstrate that a polyketal-microRNA delivery vehicle can be used to generate various reprogrammed cells without permanent genetic manipulation in an efficient manner.
PMCID: PMC3740735  PMID: 23489923
MicroRNAs; Stem cell; Pluripotency; Nanoparticles; Polyketal
2.  Scavenger Receptor A Modulates the Immune Response to Pulmonary Cryptococcus neoformans Infection 
Scavenger receptors represent an important class of pattern recognition receptors shown to mediate both beneficial and detrimental roles in host defense against microbial pathogens. The role of the major macrophage scavenger receptor, scavenger receptor A (SRA), in the immune response against the pathogenic fungus, Cryptococcus neoformans, is unknown. To evaluate the role of SRA in anticryptococcal host defenses, SRA+/+ mice and SRA−/− mice were infected intratracheally with C. neoformans. Results show that infection of SRA−/− mice resulted in a reduction in the pulmonary fungal burden at the efferent phase (3 wk) compared with SRA+/+ mice. Improved fungal clearance in SRA−/− mice was associated with decreased accumulation of eosinophils and greater accumulation of CD4+ T cells and CD11b+ dendritic cells. Additional parameters were consistent with enhanced anti-cryptococcal immunity in the infected SRA−/− mice: 1) increased expression of the costimulatory molecules CD80 and CD86 by lung APCs, 2) decreased expression of Th2 cytokines (IL-4 and IL-13) and IL-10 in lung leukocytes and in cryptococcal Ag-pulsed splenocytes, 3) diminished IgE production in sera, and 4) increased hallmarks of classical pulmonary macrophage activation. These effects were preceded by increased expression of early pro-Th1 genes in pulmonary lymph nodes at the afferent phase (1 wk). Collectively, our data show that SRA can be exploited by C. neoformans to interfere with the early events of the afferent responses that support Th1 immune polarization. This results in amplification of Th2 arm of the immune response and subsequently impaired adaptive control of C. neoformans in the infected lungs.
PMCID: PMC4007509  PMID: 23733871
3.  Functionalized Dendrimer-Based Delivery of Angiotensin Type 1 Receptor siRNA for Preserving Cardiac Function Following Infarction 
Biomaterials  2013;34(14):3729-3736.
Cardiovascular disease (CVD) is the leading cause of death throughout the world and much pathology is associated with upregulation of inflammatory genes. Gene silencing using RNA interference is a powerful tool in regulating gene expression, but its application in CVDs has been prevented by the lack of efficient delivery systems. We report here the development of tadpole dendrimeric materials for siRNA delivery in a rat ischemia-reperfusion (IR) model. Angiotensin II (Ang II) type 1 receptor (AT1R), the major receptor that mediates most adverse effects of Ang II, was chosen to be the silencing targeting. Among the three tadpole dendrimers synthesized, the oligo-arginine conjugated dendrimer loaded with siRNA demonstrated effective down-regulation in AT1R expression in cardiomyocytes in vitro. When the dendrimeric material was applied in vivo, the siRNA delivery prevented the increase in AT1R levels and significantly improved cardiac function recovery compared to saline injection or empty dendrimer treated groups after IR injury. These experiments demonstrate a potential treatment for dysfunction caused by IR injury and may represent an alternative to AT1R blockade.
PMCID: PMC3594544  PMID: 23433774
Dendrimer; Cardiomyocyte; Gene Expression; Ischemia-Reperfusion
4.  Over-Expression of Catalase in Myeloid Cells Confers Acute Protection Following Myocardial Infarction 
Cardiovascular disease is the leading cause of death in the United States and new treatment options are greatly needed. Oxidative stress is increased following myocardial infarction and levels of antioxidants decrease, causing imbalance that leads to dysfunction. Therapy involving catalase, the endogenous scavenger of hydrogen peroxide (H2O2), has been met with mixed results. When over-expressed in cardiomyocytes from birth, catalase improves function following injury. When expressed in the same cells in an inducible manner, catalase showed a time-dependent response with no acute benefit, but a chronic benefit due to altered remodeling. In myeloid cells, catalase over-expression reduced angiogenesis during hindlimb ischemia and prevented monocyte migration. In the present study, due to the large inflammatory response following infarction, we examined myeloid-specific catalase over-expression on post-infarct healing. We found a significant increase in catalase levels following infarction that led to a decrease in H2O2 levels, leading to improved acute function. This increase in function could be attributed to reduced infarct size and improved angiogenesis. Despite these initial improvements, there was no improvement in chronic function, likely due to increased fibrosis. These data combined with what has been previously shown underscore the need for temporal, cell-specific catalase delivery as a potential therapeutic option.
PMCID: PMC4057773  PMID: 24853285
oxidative stress; myocardial infarction; antioxidant therapy
5.  A Novel AX+/BX− Paradigm to Assess Fear Learning and Safety-Signal Processing with Repeated-Measure Designs 
Journal of neuroscience methods  2013;214(2):177-183.
One of the core symptoms of anxiety disorders, such as Post-Traumatic Stress Disorder is the failure to overcome feelings of danger despite being in a safe environment. This inability likely stems from an inability to fully process safety signals, which are cues in the environment, that enable healthy individuals to over-ride fear in aversive situations. Studies examining safety signal learning in rodents, humans, and non-human primates currently rely on between-groups designs. Because repeated-measures designs reduce the number of subjects required, and facilitate a broader range of safety signal studies, the current project sought to develop a repeated-measures safety-signal learning paradigm in non-human primates. Twelve healthy rhesus macaques of both sexes received three rounds of auditory fear-potentiated startle training and testing using an AX+/BX− design with all visual cues. Cue AX was paired with an aversive blast of air, whereas the same X cue in compound with another B cue (BX) signaled the absence of an air blast. Hence, cue B served as a safety signal. Once animals consistently discriminated between the aversive (AX+) and safe (BX−) cues, measured by greater startle amplitude in the presence of AX vs. BX, they were tested for conditioned inhibition by eliciting startle in the presence of a novel ambiguous combined cue (AB). Similar to previous AX+/BX− studies, healthy animals rapidly learned to discriminate between the AX+ and BX− cues as well as demonstrate conditioned inhibition in the presence of the combined AB cue (i.e. lower startle amplitude in the presence of AB vs AX). Additionally, animals performed consistently across three rounds of testing using three new cues each time. The results validate this novel method that will serve as a useful tool for better understanding the mechanisms for the regulation of fear and anxiety.
PMCID: PMC3644366  PMID: 23376500
6.  Targeting Extracellular DNA to Deliver IGF-1 to the Injured Heart 
Scientific Reports  2014;4:4257.
There is a great need for the development of therapeutic strategies that can target biomolecules to damaged myocardium. Necrosis of myocardium during a myocardial infarction (MI) is characterized by extracellular release of DNA, which can serve as a potential target for ischemic tissue. Hoechst, a histological stain that binds to double-stranded DNA can be conjugated to a variety of molecules. Insulin-like growth factor-1 (IGF-1), a small protein/polypeptide with a short circulating-half life is cardioprotective following MI but its clinical use is limited by poor delivery, as intra-myocardial injections have poor retention and chronic systemic presence has adverse side effects. Here, we present a novel delivery vehicle for IGF-1, via its conjugation to Hoechst for targeting infarcted tissue. Using a mouse model of ischemia-reperfusion, we demonstrate that intravenous delivery of Hoechst-IGF-1 results in activation of Akt, a downstream target of IGF-1 and protects from cardiac fibrosis and dysfunction following MI.
PMCID: PMC3945489  PMID: 24604065
7.  Mapping of the Mouse Olfactory System with Manganese-Enhanced Magnetic Resonance Imaging and Diffusion Tensor Imaging 
Brain structure & function  2012;218(2):527-537.
As the power of studying mouse genetics and behavior advances, research tools to examine systems level connectivity in the mouse are critically needed. In this study, we compared statistical mapping of the olfactory system in adult mice using manganese-enhanced MRI (MEMRI) and diffusion tensor imaging (DTI) with probabilistic tractography. The primary goal was to determine whether these complementary techniques can determine mouse olfactory bulb connectivity consistent with known anatomical connections. For MEMRI, 3D T1 weighted images were acquired before and after bilateral nasal administration of MnCl2 solution. Concomitantly, high resolution diffusion-tensor images were obtained ex vivo from a second group of mice and processed with a probabilistic tractography algorithm originating in the olfactory bulb. Incidence maps were created by co-registering and overlaying data from the two scan modalities. The resulting maps clearly show pathways between the olfactory bulb and amygdala, piriform cortex, caudate putamen, and olfactory cortex in both the DTI and MEMRI techniques that are consistent with the known anatomical connections. These data demonstrate that MEMRI and DTI are complementary, high-resolution neuroimaging tools that can be applied to mouse genetic models of olfactory and limbic system connectivity.
PMCID: PMC3425724  PMID: 22527121
Statistical Mapping; Diffusion Tensor Imaging (DTI); Manganese Enhanced MRI (MEMRI); Olfactory System; Mouse
8.  Organ-wide Telomeric Status in Diseased and Disease-free Prostatic Tissues 
The Prostate  2010;70(13):1471-1479.
Telomere attrition occurs early in the development of prostatic adenocarcinoma. However, little is known about either telomere status in benign prostatic hyperplasia (BPH), or the spatial and organ-wide distribution of potential telomere aberrations throughout all areas of prostatic glands affected by cancer or BPH.
Slot blot titration assay was used to determine telomere DNA content (TC), a proxy for telomere length, in macrodissected tissue consisting of 54 normal samples from 5 disease-free prostates, 128 BPH samples from 4 non-cancerous prostates, and 45 tumor, 73 BPH, and 4 prostatic intraepithelial neoplasia (PIN) samples from 5 cancerous prostates.
Compared to TC in normal prostate samples (n=54; TC mean=0.98), tumor samples displayed telomere attrition (n=45; TC mean=0.67). TC in PIN samples was similar to tumors. BPH samples from cancerous prostates were similar to TC in tumors and also displayed telomere shortening (n=73; TC mean=0.76), whereas BPH samples from non-cancerous prostates displayed longer telomeres (n=128; TC mean=1.06). In prostates affected by adenocarcinoma, areas of potential telomere attrition occurred in histologically normal tissues through the entire gland. However, three-dimensional zoning revealed a pattern of increasing TC as a function of distance from the primary (index) tumor.
Spatial distributions of TC in prostate specimens indicate a complex “field effect” with varying contributions from both cancer and BPH. The observation that telomere length variations occur in fields of histologically normal tissues surrounding the tumor is of clinical importance, as it may have implications for the diagnosis and focal therapy of prostate cancer.
PMCID: PMC3920907  PMID: 20687220
Telomere alterations; prostate cancer; benign prostatic hyperplasia; field cancerization
9.  Comparative Genomics of Cultured and Uncultured Strains Suggests Genes Essential for Free-Living Growth of Liberibacter 
PLoS ONE  2014;9(1):e84469.
The full genomes of two uncultured plant pathogenic Liberibacter, Ca. Liberibacter asiaticus and Ca. Liberibacter solanacearum, are publicly available. Recently, the larger genome of a closely related cultured strain, Liberibacter crescens BT-1, was described. To gain insights into our current inability to culture most Liberibacter, a comparative genomics analysis was done based on the RAST, KEGG, and manual annotations of these three organisms. In addition, pathogenicity genes were examined in all three bacteria. Key deficiencies were identified in Ca. L. asiaticus and Ca. L. solanacearum that might suggest why these organisms have not yet been cultured. Over 100 genes involved in amino acid and vitamin synthesis were annotated exclusively in L. crescens BT-1. However, none of these deficiencies are limiting in the rich media used to date. Other genes exclusive to L. crescens BT-1 include those involved in cell division, the stringent response regulatory pathway, and multiple two component regulatory systems. These results indicate that L. crescens is capable of growth under a much wider range of conditions than the uncultured Liberibacter strains. No outstanding differences were noted in pathogenicity-associated systems, suggesting that L. crescens BT-1 may be a plant pathogen on an as yet unidentified host.
PMCID: PMC3885570  PMID: 24416233
10.  Neonatal lesions of orbital frontal areas 11/13 in monkeys alter goal-directed behavior but spare fear conditioning and safety signal learning 
Recent studies in monkeys have demonstrated that damage to the lateral subfields of orbital frontal cortex (OFC areas 11/13) yields profound changes in flexible modulation of goal-directed behaviors and deficits in fear regulation. Yet, little consideration has been placed on its role in emotional and social development throughout life. The current study investigated the effects of neonatal lesions of the OFC on the flexible modulation of goal-directed behaviors and fear responses in monkeys. Infant monkeys received neonatal lesions of OFC areas 11/13 or sham-lesions during the first post-natal week. Modulation of goal-directed behaviors was measured with a devaluation task at 3–4 and 6–7 years. Modulation of fear reactivity by safety signals was assessed with the AX+/BX− fear-potentiated-startle paradigm at 6–7 years. Similar to adult-onset OFC lesions, selective neonatal lesions of OFC areas 11/13 yielded a failure to modulate behavioral responses guided by changes in reward value, but spared the ability to modulate fear responses in the presence of safety signals. These results suggest that these areas play a critical role in the development of behavioral adaptation during goal-directed behaviors, but not or less so, in the development of the ability to process emotionally salient stimuli and to modulate emotional reactivity using environmental contexts, which could be supported by other OFC subfields, such as the most ventromedial subfields (i.e., areas 14/25). Given similar impaired decision-making abilities and spared modulation of fear after both neonatal lesions of either OFC areas 11 and 13 or amygdala (Kazama et al., 2012; Kazama and Bachevalier, 2013), the present results suggest that interactions between these two neural structures play a critical role in the development of behavioral adaptation; an ability essential for the self-regulation of emotion and behavior that assures the maintenance of successful social relationships.
PMCID: PMC3940964  PMID: 24624054
orbitofrontal cortex (OFC); flexible decision-making; safety-signal processing; non-human primate development; areas 11 and 13
11.  Effect of bone marrow-derived extracellular matrix on cardiac function after ischemic injury 
Biomaterials  2012;33(31):10.1016/j.biomaterials.2012.07.010.
Ischemic heart disease is a leading cause of death, with few options to retain ventricular function following myocardial infarction. Hematopoietic-derived progenitor cells contribute to angiogenesis and tissue repair following ischemia reperfusion injury. Motivated by the role of bone marrow extracellular matrix (BM-ECM) in supporting the proliferation and regulation of these cell populations, we investigated BM-ECM injection in myocardial repair. In BM-ECM isolated from porcine sternum, we identified several factors important for myocardial healing, including vascular endothelial growth factor, basic fibroblast growth factor-2, and platelet-derived growth factor-BB. We further determined that BM-ECM serves as an adhesive substrate for endothelial cell proliferation. Bone marrow ECM was injected in a rat model of myocardial infarction, with and without a methylcellulose carrier gel. After one day, reduced infarct area was noted in rats receiving BM-ECM injection. After seven days we observed improved fractional shortening, decreased apoptosis, and significantly lower macrophage counts in the infarct border. Improvements in fractional shortening, sustained through 21 days, as well as decreased fibrotic area, enhanced angiogenesis, and greater c-kit-positive cell presence were associated with BM-ECM injection. Notably, the concentrations of BM-ECM growth factors were 103–108 fold lower than typically required to achieve a beneficial effect, as reported in pre-clinical studies that have administered single growth factors alone.
PMCID: PMC3849033  PMID: 22819498
Bone marrow; Growth factors; ECM (extracellular matrix); Heart; Thermally responsive material; Porcine tissue
12.  Early Intervention May Prevent the Development of PTSD: A Randomized Pilot Civilian Study with Modified Prolonged Exposure 
Biological psychiatry  2012;72(11):957-963.
Posttraumatic stress disorder is a major public health concern with long term sequelae. There are no accepted interventions delivered in the immediate aftermath of trauma. This study tested an early intervention aimed at modifying the memory to prevent the development of PTSD prior to memory consolidation.
Patients (N=137) were randomly assigned to receive 3 sessions of an early intervention beginning in the emergency department (ED) compared to an assessment only control group. Posttraumatic stress reactions (PTSR) were assessed at 4 and 12 weeks post-injury and depression at baseline and week 4. The intervention consisted of modified prolonged exposure including imaginal exposure to the trauma memory, processing of traumatic material, and in vivo and imaginal exposure homework.
Patients were assessed an average of 11.79 hours post-trauma. Intervention participants reported significantly lower PTSR than the assessment group at 4 weeks post-injury, p < 0.01, and at 12 weeks post-injury, p < 0.05, and significantly lower depressive symptoms at Week 4 than the assessment group, p < 0.05. In a subgroup analysis the intervention was the most effective at reducing PTSD in rape victims at Week 4 (p=.004) and Week 12 (p=.05).
These findings suggest that the modified prolonged exposure intervention initiated within hours of the trauma in the ED is successful at reducing PTSR and depression symptoms one and three months after trauma exposure and is safe and feasible. This is the first behavioral intervention delivered immediately post-trauma that has been shown to be effective at reducing PTSR.
PMCID: PMC3467345  PMID: 22766415
early intervention; secondary prevention; PTSD; Acute Stress Disorder; prolonged exposure; memory consolidation
13.  A Naturally-Derived Cardiac Extracellular Matrix Enhances Cardiac Progenitor Cell Behavior In Vitro 
Acta biomaterialia  2012;8(12):4357-4364.
Myocardial infarction (MI) produces a collagen scar, altering the local microenvironment and impeding cardiac function. Cell therapy is a promising therapeutic option to replace the billions of myocytes lost following MI. Despite early successes, chronic function remains impaired and is likely a result of poor cellular retention, proliferation, and differentiation/maturation. While some efforts to deliver cells with scaffolds attempt to address these shortcomings, they lack the natural cues required for optimal cell function. The goal of this study was to determine whether a naturally-derived cardiac extracellular matrix (cECM) could enhance cardiac progenitor cell (CPC) function in vitro. CPCs were isolated via magnetic sorting of c-kit+ cells and were grown on plates coated with either cECM or collagen I (COL). Our results show an increase in early cardiomyocyte markers on cECM compared to COL, as well as corresponding protein expression later. CPCs show stronger serum-induced proliferation on cECM as compared to COL, as well as increased resistance to apoptosis following serum-starvation. Finally, a microfluidic adhesion assay demonstrated stronger adhesion of CPCs to cECM compared with COL. These data suggest that cECM may be optimal for CPC therapeutic delivery, as well as provide potential mechanisms for the shortcomings in naked cell therapy.
PMCID: PMC3488121  PMID: 22842035
ECM (extracellular matrix); Progenitor Cell; Cell adhesion; Cell proliferation; Gene expression
14.  Passive Pressure–Diameter Relationship and Structural Composition of Rat Mesenteric Lymphangions 
Lymphatic Research and Biology  2012;10(4):152-163.
Lymph flow depends on both the rate of lymph production by tissues and the extent of passive and active pumping. Here we aim to characterize the passive mechanical properties of a lymphangion in both mid-lymphangion and valve segments to assess regional differences along a lymphangion, as well as evaluating its structural composition.
Methods and Results
Mesenteric lymphatic vessels were isolated and cannulated in a microchamber for pressure–diameter (P-D) testing. Vessels were inflated from 0 to 20 cmH2O at a rate of 4 cmH2O/min, and vessel diameter was continuously tracked, using an inverted microscope, video camera, and custom LabVIEW program, at both mid-lymphangion and valve segments. Isolated lymphatic vessels were also pressure-fixed at 2 and 7 cmH2O and imaged using a nonlinear optical microscope (NLOM) to obtain collagen and elastin structural information. We observed a highly nonlinear P-D response at low pressures (3–5 cmH2O), which was modeled using a three-parameter constitutive equation. No significant difference in the passive P-D response was observed between mid-lymphangion and valve regions. NLOM imaging revealed an inner elastin layer and outer collagen layer at all locations. Lymphatic valve leaflets were predominantly elastin with thick axially oriented collagen bands at the insertion points.
We observed a highly nonlinear P-D response at low pressures (3–5 cmH2O) and developed the first constitutive equation to describe the passive P-D response for a lymphangion. The passive P-D response did not vary among regions, in agreement with the composition of elastin and collagen in the lymphatic wall.
PMCID: PMC3525898  PMID: 23145980
16.  Characterization of Superoxide Dismutases in Cardiac Progenitor Cells Demonstrates a Critical Role for Manganese Superoxide Dismutase 
Stem Cells and Development  2012;21(17):3136-3146.
Transplantation of cardiac progenitor cells (CPCs) is currently in early clinical testing as a potential therapeutic strategy. Superoxide is increased in the ischemic myocardium and poor survival of cells is one of the major limitations of cell transplantation therapy. Superoxide dismutase (SOD) levels were analyzed in c-kit-positive CPCs isolated from rat myocardium to identify their roles in protection against oxidative stress-induced apoptosis in vitro. CPCs were subjected to oxidative stress using xanthine/xanthine oxidase (XXO) and little apoptosis was detected. CPCs contained significantly higher levels of SOD1 and SOD2 as compared with adult cardiac cell types, both at the protein and activity levels. Both SOD1 and SOD2 were increased by XXO at the mRNA and protein level, suggesting compensatory adaptation. Only knockdown of SOD2 and not SOD1 with siRNA sensitized the cells to XXO-apoptosis, despite only accounting for 10% of total SOD levels. Finally, we found XXO activated Akt within 10 min, and this regulated both SOD2 gene expression and protection against apoptosis. Rat CPCs are resistant to superoxide-induced cell death, primarily through higher levels of SOD2 compared to adult cardiac-derived cells. Exposure to superoxide increases expression of SOD2 in an Akt-dependent manner and regulates CPC survival during oxidative stress.
PMCID: PMC3495122  PMID: 22758933
17.  Inducible Renitence limits Listeria monocytogenes Escape from Vacuoles in Macrophages 
Membranes of endolysosomal compartments in macrophages are often damaged by physical or chemical effects of particles ingested through phagocytosis or by toxins secreted by intracellular pathogens. This study identified a novel inducible activity in macrophages which increases resistance of phagosomes, late endosomes and lysosomes to membrane damage. Pretreatment of murine macrophages with lipopolysaccharide, peptidoglycan, tumor necrosis factor-α or interferon-γ (IFN-γ) conferred protection against subsequent damage to intracellular membranes caused by photooxidative chemistries or by phagocytosis of ground silica or silica microspheres. Phagolysosome damage was partially dependent on reactive oxygen species, but was independent of the phagocyte oxidase. IFN-γ-stimulated macrophages from mice lacking the phagocyte oxidase inhibited escape from vacuoles by the intracellular pathogen Listeria monocytogenes (L.m.), which suggested a role for this inducible renitence (resistance to pressure) in macrophage resistance to infection by pathogens that damage intracellular membranes. Renitence and inhibition of L.m. escape were partially attributable to heat shock protein-70 (HSP70). Thus, renitence is a novel, inducible activity of macrophages which maintains or restores the integrity of endolysosomal membranes.
PMCID: PMC3478491  PMID: 23002437
18.  High Titers of IgE Antibody to Dust Mite Allergen and the Risk for Wheezing Among Asthmatic Children Infected with Rhinovirus 
The relevance of allergic sensitization, judged by titers of serum IgE antibodies, to the risk of an asthma exacerbation caused by rhinovirus is unclear.
To examine the prevalence of rhinovirus infections in relation to the atopic status of children treated for wheezing in Costa Rica, a country with an increased asthma burden.
The children enrolled (n=287) were 7 through 12 years old. They included 96 with acute wheezing, 65 with stable asthma, and 126 non-asthmatic controls. PCR methods, including gene sequencing to identify rhinovirus strains, were used to identify viral pathogens in nasal washes. Results were examined in relation to wheezing, total IgE, allergen-specific IgE antibody, and levels of expired nitric oxide (FENO).
Sixty-four percent of wheezing children compared to 13% of children with stable asthma and 17% of the non-asthmatic controls tested positive for rhinovirus (p<0.001 for both comparisons). Among wheezing subjects, 75% of the rhinoviruses detected were Group C strains. High titers of IgE antibodies to dust mite allergen (especially Dermatophagoides sp) were common and correlated significantly with levels of total IgE and FENO. The greatest risk for wheezing was observed among children with titers of IgE antibodies to dust mite ≥17.5 IU/ml who tested positive for rhinovirus (odds ratio for wheezing: 31.5; 95% CI 8.3–108, p<0.001).
High titers of IgE antibody to dust mite allergen were common and significantly increased the risk for acute wheezing provoked by rhinovirus among asthmatic children.
PMCID: PMC3792652  PMID: 22560151
acute asthma; dust mite specific IgE; emergency room visits; viral respiratory tract infections; rhinovirus strain C; total serum IgE; inhaled allergens; exhaled nitric oxide (FENO)
19.  Effects of Substance P in the Amygdala, Ventromedial Hypothalamus and Periaqueductal Gray on Fear Potentiated Startle 
The neural pathways through which substance P (SP) influences fear and anxiety are poorly understood. However, the amygdala, a brain area repeatedly implicated in fear and anxiety processes, is known to contain large numbers of SP containing neurons and SP receptors. Several studies have implicated SP neurotransmission within the amygdala in anxiety processes. In the present study, we evaluated the effects of site-specific infusions of a SP receptor antagonist, GR 82334, on conditioned fear responses using the fear-potentiated startle paradigm. GR 82334 infusion into the basolateral (BLA) or the medial (MeA) nuclei of the amygdala, but not into the central nucleus (CeA) of the amygdala, dose-dependently reduced fear-potentiated startle. Similar effects were obtained with GR 82334 infusion into the ventromedial nucleus of the hypothalamus (VMH), to which the MeA projects, and into the rostral dorsolateral periaqueductal gray (PAG), to which the VMH projects, but not into the deep layers of the superior colliculus/deep mesencephalic nucleus (dSC/DpMe), an output of the CeA previously shown to be important for fear-potentiated startle. Consistent with previous findings, infusion of the AMPA receptor antagonist, NBQX, into the dSC/DpMe, but not into the PAG, did disrupt fear-potentiated startle. These findings suggest that multiple outputs from the amygdala play a critical role in fear-potentiated startle and that SP plays a critical, probably modulatory role, in the MeA to VMH to PAG to the startle pathway based on these and data from others.
PMCID: PMC3792658  PMID: 18418359
Amygdala; Hypothalamus; Periaqueductal Gray; Superior Colliculus; Midbrain; GR 82334; Morphine; Anxiety; CRH; Tachykinin
20.  Identification of the Mutation Responsible for the Temperature-Sensitive Lipopolysaccharide O-Antigen Defect in the Pseudomonas aeruginosa Cystic Fibrosis Isolate 2192 
Journal of Bacteriology  2013;195(7):1504-1514.
Pseudomonas aeruginosa in the lungs of cystic fibrosis (CF) patients is characterized by a series of genotypic and phenotypic changes that reflect the transition from acute to chronic infection. These include the overproduction of the exopolysaccharide alginate and the loss of complete lipopolysaccharide (LPS). LPS is a major component of the Gram-negative outer membrane and is composed of lipid A, core oligosaccharide, and O antigen. In this report, we show that the LPS defect of the P. aeruginosa chronic infection isolate 2192 is temperature sensitive. When grown at 25°C, 2192 expresses serotype O1 LPS with a moderate chain length and in reduced amounts relative to those of a wild-type serotype O1 laboratory strain (stO1). In contrast, 2192 expresses no LPS O antigen when grown at 37°C. This is the first time that a temperature-sensitive defect in O-antigen production has been reported. Using complementation analyses with a constructed wbpM deletion mutant of stO1, we demonstrate that the temperature-sensitive O-antigen production defect in 2192 is due to a mutation in wbpM, which encodes a UDP-4,6-GlcNAc dehydratase involved in O-antigen synthesis. The mutation, a deletion of a single amino acid (V636) from the extreme C terminus of WbpM, renders the protein less stable than its wild-type counterpart. This residue of WbpM, which is critical for stability and function, is located outside of the recognized domains of the protein and may provide insight into the structure-function relationship of this enzyme, which is found in all 20 serotypes of P. aeruginosa. We also identify a promoter of wbpM, map a transcriptional start site of wbpM, and show that mucoidy plays a role in the loss of expression of high-molecular-weight LPS in this CF isolate.
PMCID: PMC3624535  PMID: 23354750
21.  Cellular Encapsulation Enhances Cardiac Repair 
Stem cells for cardiac repair have shown promise in preclinical trials, but lower than expected retention, viability, and efficacy. Encapsulation is one potential strategy to increase viable cell retention while facilitating paracrine effects.
Methods and Results
Human mesenchymal stem cells (hMSC) were encapsulated in alginate and attached to the heart with a hydrogel patch in a rat myocardial infarction (MI) model. Cells were tracked using bioluminescence (BLI) and cardiac function measured by transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR). Microvasculature was quantified using von Willebrand factor staining and scar measured by Masson's Trichrome. Post‐MI ejection fraction by CMR was greatly improved in encapsulated hMSC‐treated animals (MI: 34±3%, MI+Gel: 35±3%, MI+Gel+hMSC: 39±2%, MI+Gel+encapsulated hMSC: 56±1%; n=4 per group; P<0.01). Data represent mean±SEM. By TTE, encapsulated hMSC‐treated animals had improved fractional shortening. Longitudinal BLI showed greatest hMSC retention when the cells were encapsulated (P<0.05). Scar size at 28 days was significantly reduced in encapsulated hMSC‐treated animals (MI: 12±1%, n=8; MI+Gel: 14±2%, n=7; MI+Gel+hMSC: 14±1%, n=7; MI+Gel+encapsulated hMSC: 7±1%, n=6; P<0.05). There was a large increase in microvascular density in the peri‐infarct area (MI: 121±10, n=7; MI+Gel: 153±26, n=5; MI+Gel+hMSC: 198±18, n=7; MI+Gel+encapsulated hMSC: 828±56 vessels/mm2, n=6; P<0.01).
Alginate encapsulation improved retention of hMSCs and facilitated paracrine effects such as increased peri‐infarct microvasculature and decreased scar. Encapsulation of MSCs improved cardiac function post‐MI and represents a new, translatable strategy for optimization of regenerative therapies for cardiovascular diseases.
PMCID: PMC3835246  PMID: 24113327
angiogenesis; cardiovascular diseases; heart failure; ischemia; myocardial infarction
22.  Poststroke Hip Fracture: Prevalence, Clinical Characteristics, Mineral-Bone Metabolism, Outcomes, and Gaps in Prevention 
Stroke Research and Treatment  2013;2013:641943.
Objective. To assess the prevalence, clinical and laboratory characteristics, and short-term outcomes of poststroke hip fracture (HF). Methods. A cross-sectional study of 761 consecutive patients aged ≥60 years (82.3 ± 8.8 years; 75% females) with osteoporotic HF. Results. The prevalence of poststroke HF was 13.1% occurring on average 2.4 years after the stroke. The poststroke group compared to the rest of the cohort had a higher proportion of women, subjects with dementia, history of TIA, hypertension, coronary artery disease, secondary hyperparathyroidism, higher serum vitamin B12 levels (>350 pmol/L), walking aid users, and living in residential care facilities. The majority of poststroke HF patients had vitamin D insufficiency (68%) and excess bone resorption (90%). This group had a 3-fold higher incidence of postoperative myocardial injury and need for institutionalisation. In multivariate analysis, independent indicators of poststroke HF were female sex (OR 3.6), history of TIA (OR 5.2), dementia (OR 4.1), hypertension (OR 3.2), use of walking aid (OR 2.5), and higher vitamin B12 level (OR 2.3). Only 15% of poststroke patients received antiosteoporotic therapy prior to HF. Conclusions. Approximately one in seven HFs occurs in older stroke survivors and are associated with poorer outcomes. Early implementation of fracture prevention strategies is needed.
PMCID: PMC3800649  PMID: 24187647
23.  Detection Of Ras GTPase Protein Radicals Through Immuno-Spin Trapping* 
Free radical biology & medicine  2012;53(6):1339-1345.
Over the past decade immuno-spin trapping (IST) has been used to detect and identify protein radical sites in numerous heme and metalloproteins. To date, however, the technique has had little application toward non-metalloproteins. In this study, we demonstrate the successful application of IST in a system free of transition metals and present the first conclusive evidence of ·NO-mediated protein radical formation in the HRas GTPase. HRas is a non-metalloprotein that plays a critical role in regulating cell growth control. Protein radical formation in Ras GTPases has long been suspected of initiating premature release of bound guanine nucleotide. This action results in altered Ras activity both in vitro and in vivo. As described herein, successful application of IST may provide a means for detecting and identifying radical-mediated Ras activation in many different cancers and disease states where Ras GTPases play an important role.
PMCID: PMC3549333  PMID: 22819983
Ras GTPase; radical-mediated activation; protein radical; immuno-spin trapping
24.  Circulating folate, vitamin B12, homocysteine, vitamin B12 transport proteins and risk of prostate cancer: a case-control study, systematic review and meta-analysis 
Disturbed folate metabolism is associated with an increased risk of some cancers. Our objective was to determine whether blood levels of folate, vitamin B12 and related metabolites were associated with prostate cancer risk.
Matched case-control study nested within the UK population-based ProtecT study of PSA-detected prostate cancer in men aged 50–69 years. Plasma concentrations of folate, B12 (cobalamin), holo-haptocorrin, holo- and total-transcobalamin, and total homocysteine (tHcy) were measured in 1,461 cases and 1,507 controls. ProtecT study estimates for associations of folate, B12, and tHcy with prostate cancer risk were included in a meta-analysis, based on a systematic review.
In the ProtecT study, increased B12 and holo-haptocorrin concentrations showed positive associations with prostate cancer risk (highest vs lowest quartile of B12 odds ratio (OR)=1.17 (95% CI 0.95–1.43), P-for-trend=0.06; highest vs lowest quartile of holo-haptocorrin OR=1.27 (1.04–1.56), P-for-trend=0.01); folate, holo-transcobalamin and tHcy were not associated with prostate cancer risk. In the meta-analysis, circulating B12 levels were associated with an increased prostate cancer risk (pooled OR=1.10 (1.01–1.19) per 100 pmol/L increase in B12, P=0.002); the pooled OR for the association of folate with prostate cancer was positive (OR=1.11 (0.96–1.28) per 10 nmol/L, P=0.2) and conventionally statistically significant if ProtecT (the only case-control study) was excluded (OR=1.18 (1.00–1.40) per 10 nmol/L, P=0.02).
Vitamin B12 and (in cohort studies) folate were associated with increased prostate cancer risk.
Given current controversies over mandatory fortification, further research is needed to determine whether these are causal associations.
PMCID: PMC3759018  PMID: 20501771
folate; vitamin B12; cobalamin; transcobalamin; haptocorrin; homocysteine; folate-mediated one-carbon metabolism; prostate cancer
Molecular psychiatry  2012;18(3):308-319.
The lateral division of the bed nucleus of the stria terminalis (BNST), which forms part of the circuitry regulating fear and anxiety, contains a large number of neurons expressing corticotropin releasing factor (CRF), a neuropeptide that plays a prominent role in the etiology of fear- and anxiety-related psychopathologies. Stress increases CRF expression within BNST neurons, implicating these cells in stress- and anxiety-related behaviors. These experiments examined the effect of chronically enhanced CRF expression within BNST neurons on conditioned and unconditioned anxiety-related behavior by using a lentiviral vector containing a promoter that targets CRF gene over-expression (OE) to CRFergic cells. We found that BNST CRF over-expression did not affect unconditioned anxiety-like responses in the elevated plus maze or basal acoustic startle amplitude. CRF OE induced prior to training weakened sustained fear (conditioned anxiety); when induced after conditioning, CRF OE increased expression of the conditioned emotional memory. Increased BNST CRF expression did not affect plasma corticosterone concentration but did decrease CRFR1 receptor density within the BNST and CRFR2 receptor density within the dorsal portion of the caudal dorsal raphe nucleus. These data raise the possibility that the observed behavioral effects may be mediated by enhanced CRF receptor signaling or compensatory changes in CRF receptor density within these structures. Together, these studies demonstrate that CRF neurons within the lateral BNST modulate conditioned anxiety-like behaviors and also suggest that enhanced CRF expression within these neurons may contribute to inappropriate regulation of emotional memories.
PMCID: PMC3578178  PMID: 22290119
bed nucleus of the stria terminalis; corticotropin releasing factor; fear; anxiety; startle; HPA axis

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