Browsing by Author "Basile, David"

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    A Therapeutic Extracorporeal Device for Specific Removal of Pathologic Asymmetric Dimethylarginine from the Blood
    (Karger, 2022) Lee, Young; Steinbach, Sarah M. L.; Basile, David; Singh, Jaipal; Anatomy, Cell Biology and Physiology, School of Medicine
    Introduction: Blood levels of uremic toxin, asymmetric dimethylarginine (ADMA), are strongly associated with mortality in sepsis, renal failure, and cardiovascular and renal disease patients. Methods: An extracorporeal approach to reduce pathological ADMA was developed. The dimethylarginine dimethylaminohydrolase (DDAH) was immobilized on agarose beads to prepare a cartridge. The efficacy of cartridge for ADMA lowering in blood was investigated. Results: The DDAH beads and cartridge reduced ADMA from solution or plasma. The magnitude of ADMA removal was dependent on the quantity of DDAH linked to the beads and the flow rate. When tested in association with plasmapheresis, the DDAH-cartridge was highly effective in ADMA removal from the blood and improved the arginine/ADMA ratio in a pig model. Conclusion: A new, safe, and effective extracorporeal approach to lower ADMA was developed which may have application in improving outcomes in patients with vascular complications and risk of mortality associated with high ADMA.
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    Mechanisms of HIV-Nef Induced Endothelial Cell Stress: Implications of HIV-Nef Protein Persistence in Aviremic HIV Patients
    (2019-05) Chelvanambi, Sarvesh; Clauss, Matthias; Basile, David; Day, Richard; Yu, Andy
    HIV-associated cardio-pulmonary vascular pathologies such as coronary artery disease, pulmonary hypertension and emphysema remain a major issue in the HIVinfected population even in the era of antiretroviral therapy (ART). The continued production of HIV encoded pro-apoptotic protein, such as Nef in latently HIV-infected cells is a possible mechanism for vascular dysfunction underlying these diseases. HIVNef persists in two compartments in these patients: (i) extracellular vesicles (EV) of plasma and bronchoalveolar lavage (BAL) fluid and (ii) PBMC and BAL derived cells. Here I demonstrate that the presence of HIV-Nef protein in cells and EV is capable of stressing endothelial cells by inducing ROS production leading to endothelial cell apoptosis. HIV-Nef protein hijacks host cell signaling by interacting with small GTP binding protein Rac1 which activates PAK2 to promote the release of pro-apoptotic cargo containing EV and surface expression of pro-apoptotic protein Endothelial Monocyte Activating Polypeptide II (EMAPII). Using this mechanism, Nef protein robustly induces apoptosis in Human Coronary Artery Endothelial Cells and Human Lung microvascular endothelial cells. Endothelial specific expression of HIV-Nef protein in transgenic mice was sufficient to induce vascular pathologies as evidenced by impaired endothelium mediated vasodilation of the aorta and vascular remodeling and emphysema like alveolar rarefaction in the lung. Furthermore, EV isolated from HIV patients on ART was capable of inducing endothelial apoptosis in a Nef dependent fashion. Of therapeutic interest, EMAPII neutralizing antibodies to block EMAPII mediated apoptosis and statin treatment to ameliorate Nef induced Rac1 signaling was capable of blocking Nef induced endothelial stress in both in vivo and in vitro. In conclusion, HIV-Nef protein uses a Rac1-Pak2 signaling axis to promote its dissemination in EV, which in turn induces endothelial cell stress after its uptake.
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    Mechanisms Underlying Cardiovascular Benefits of Sodium Glucose Co-Transporter-2 Inhibitors: Myocardial Substrate or Sodium/Hydrogen Exchanger?
    (2020-01) Baker, Hana Elisabeth; Tune, Johnathan D.; Basile, David; Goodwill, Adam; Kowala, Mark; Mather, Kieren; Michael, Mervyn (Dod)
    Recent clinical outcome studies demonstrate that Sodium glucose cotransporter 2 inhibitors (SGLT2i) significantly reduce major adverse cardiovascular events and heart failure outcomes in subjects with type 2 diabetes mellitus. At present, several hypotheses have been proposed to explain the observed cardiovascular benefit of SGLT2i, however, the mechanisms responsible remain to be elucidated. This investigation tested the hypothesis that SGLT2i improves cardiac function and efficiency during acute, regional ischemia/reperfusion injury via preferential shifts in myocardial substrate selection and/or inhibition of cardiac sodium/hydrogen exchanger-1 (NHE-1). Our initial investigation evaluated the effects of 24 hour pretreatment of the SGLT2i canagliflozin on cardiac contractile function, substrate utilization, and efficiency before and during regional myocardial ischemia/reperfusion injury in healthy swine. At the onset of ischemia, canagliflozin increased left ventricular end diastolic and systolic volumes which returned to baseline with reperfusion. This increased end diastolic volume was directly associated with increased stroke volume and stroke work relative to controls during ischemia. Canagliflozin also increased cardiac work efficiency during ischemia relative to control swine. No differences in myocardial substrate uptake of glucose, lactate, fatty acids or ketones were detected between groups. In separate experiments using a longer 60 min coronary occlusion, canagliflozin significantly diminished myocardial infarct size. Subsequent studies investigated the effect of an acute administration (15-30 min pre-treatment) of canagliflozin and the NHE-1i cariporide on cardiac contractile function efficiency in response to myocardial ischemia/reperfusion injury. Similar to our initial studies, canagliflozin increased diastolic filling, stroke work and improved cardiac work efficiency relative to untreated control hearts during the ischemic period. In contrast, cariporide did not alter ventricular filling volume, cardiac output or work efficiency at any time point. Additional examination of AP-1 cells transfected with wild-type NHE-1 showed dose-dependent inhibition of NHE-1 activity by cariporide, while canagliflozin had minimal effect on overall activity. This investigation demonstrates that SGLT2i improves cardiac function and efficiency during acute, regional ischemia in healthy swine. However, the present data fail to support the hypothesis that these SGLT2i-mediated improvements involve either preferential alterations in myocardial substrate utilization or the inhibition of NHE-1 activity.
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    Specific Lowering of Asymmetric Dimethylarginine by Pharmacological Dimethylarginine Dimethylaminohydrolase Improves Endothelial Function, Reduces Blood Pressure and Ischemia-Reperfusion Injury
    (American Society for Pharmacology and Experimental Therapeutics, 2021) Lee, Young; Mehrotra, Purvi; Basile, David; Ullah, Mahbub; Singh, Arshnoor; Skill, Nicholas; Younes, Subhi Talal; Sasser, Jennifer; Shekhar, Anantha; Singh, Jaipal; Cellular and Integrative Physiology, School of Medicine
    Multiple clinical and preclinical studies have demonstrated that plasma levels of asymmetric dimethylarginine (ADMA) are strongly associated with hypertension, diabetes, and cardiovascular and renal disease. Genetic studies in rodents have provided evidence that ADMA metabolizing dimethylarginine dimethylaminohydrolase (DDAH)-1 plays a role in hypertension and cardiovascular disease. However, it remains to be established whether ADMA is a bystander, biomarker, or sufficient contributor to the pathogenesis of hypertension and cardiovascular and renal disease. The goal of the present investigation was to develop a pharmacological molecule to specifically lower ADMA and determine the physiologic consequences of ADMA lowering in animal models. Further, we sought to determine whether ADMA lowering will produce therapeutic benefits in vascular disease in which high ADMA levels are produced. A novel long-acting recombinant DDAH (M-DDAH) was produced by post-translational modification, which effectively lowered ADMA in vitro and in vivo. Treatment with M-DDAH improved endothelial function as measured by increase in cGMP and in vitro angiogenesis. In a rat model of hypertension, M-DDAH significantly reduced blood pressure (vehicle: 187 ± 19 mm Hg vs. M-DDAH: 157 ± 23 mm Hg; P < 0.05). Similarly, in a rat model of ischemia-reperfusion injury, M-DDAH significantly improved renal function as measured by reduction in serum creatinine (vehicle: 3.14 ± 0.74 mg/dl vs. M-DDAH: 1.1 ± 0.75 mg/dl; P < 0.01), inflammation, and injured tubules (vehicle: 73.1 ± 11.1% vs. M-DDAH: 22.1 ± 18.4%; P < 0.001). These pharmacological studies have provided direct evidence for a pathologic role of ADMA and the therapeutic benefits of ADMA lowering in preclinical models of endothelial dysfunction, hypertension, and ischemia-reperfusion injury. SIGNIFICANCE STATEMENT: High levels of ADMA occur in patients with cardiovascular and renal disease. A novel modified dimethylarginine dimethylaminohydrolase by PEGylation effectively lowers ADMA, improves endothelial function, reduces blood pressure and protects from ischemia-reperfusion renal injury.
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    Studies on hydrodynamic delivery as a treatment for acute kidney injury
    (2017) Kolb, Alexander; Atkinson, Simon; Bacallao, Robert; Basile, David; Dai, Guoli; Szymanski, Daniel
    Hydrodynamic delivery is a powerful tool that allows delivery of macromolecules to the kidney culminating in gene expression. This finding is important in the fight against kidney disease. Current therapy for kidney injury, specifically acute kidney injury, is lacking. Supportive care in the form of IV fluids and medications aimed at restoring Glomerular Filtration Rate (GFR) and urine output are currently used. However, even with these treatments, prognoses of patients diagnosed with this disease remains poor. We believe that hydrodynamic delivery provides a mechanism that can be used to reverse and prevent AKI. Hydrodynamic delivery following ischemic injuries leads to reductions in serum creatinine and infiltrating mononuclear cells, as well as increased renal blood flow and survival. These changes are due to reductions in vascular congestion and inflammation typically seen following injury. To determine the underlying mechanisms of gene delivery preventing AKI, we used candidate genes identified in a proteomic screen on kidneys that recovered from AKI. We selected Isocitrate Dehydrogenase II (IDH2) and Sulfotransferase 1C2 (SULT1C2) for study and found that delivery prior to injury prevents serum creatinine increase and reduces cell death. We found that gene delivery of IDH2 prevents a glycolytic shift typically seen following ischemic injuries. The mechanism underlying the prevention of this shift are seen in increased ATP stores and spare respiratory capacity allowing the cell to remain in an oxidative state. Additionally, we show that SULT1C2 post-translationally modifies the mitochondria membrane, increasing oxidative phosphorylation providing the cell with additional energy needed in times of oxidative stress. These candidate genes allow cells to remain in an oxidative state preventing the activation of cell death pathways typically activated following injury, thereby preserving normal kidney function.
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    Understanding the Integrated Pathophysiological Role of a Moonlighting Protein in Lung Development
    (2019-08) Lee, Dong Il; Schwarz, Margaret; Tune, Johnathan; Kaplan, Mark; Basile, David
    Sensing, integrating, and relaying signals from the environment through proteins, metabolites, and lipids to the lung are critical for proper development. Moonlighting proteins, such as AIMP1, are a unique subset that serves at least two independent physiological functions. Encoded by gene AIMP1, AIMP1 has two known functions: (1) C-terminus EMAP II domain of full-length AIMP1 can be secreted out of the cell to chemoattract myeloid cells; (2) intracellular full-length protein interacts with tRNA synthetases in protein translation. However, despite the linkage of protein expression levels of with several lung pathologies such as bronchopulmonary dysplasia (BPD), effectively targeting the protein encoded by AIMP1 has been a challenge due to poorly understood mechanisms. This thesis explores physiological, signaling, and immunological moonlighting mechanisms of first, the extracellular EMAP II then the intracellular AIMP1. Experiments utilize both in vitro and in vivo models, including a murine model of BPD and Cre-mediated exon-deletion knockout. Experimental results provide evidence that in the BPD model, EMAP II levels are elevated and sustained – first in bronchial epithelial cells then in macrophages. Mice exposed to sustained and elevated EMAP II protein levels resemble the BPD phenotype while neutralization partially rescued the phenotype, implying EMAP II as a potential therapeutic target against BPD. Results from studies exploring EMAP II’s signaling mechanism identify transient stimulation of JAK-STAT3 phosphorylation, commonly found in inflammation-resolving macrophages. In contrast, it induces unique transcriptional changes that are reversible both by JAK-STAT inhibitor and siRNA-mediated knockdown of Stat3. Studies using AIMP1 knockout mouse reveal a novel function for the intracellular AIMP1. AIMP1 knockout mice exhibited neonatal lethality with a respiratory distress phenotype, decreased type I alveolar cell expression, and disorganized bronchial epithelium, suggesting a role in lung maturation. In vitro experiments suggest that a portion of AIMP1 residing in the cell’s membrane interacts with various phosphatidylinositols and contributes toward F-actin deposition and assembly. Data from these experimental studies provide insight into how the various functions of the promiscuous AIMP1 gene affect lung development. These studies exemplify not only characterize novel moonlighting mechanisms of AIMP1, but also highlight the importance of characterizing moonlighting proteins to promote therapeutic preventions.