Medicine and Health Sciences Commons^™

Reduction Of Dose Calculation Errors For Patients With Metal Implants Receiving Photon Radiation Therapy, Jessie Huang-Vredevoogd

Dissertations and Theses (Open Access)

Many patients receiving external beam radiation therapy have metal implants that can affect their treatment, and these metal implants can degrade the accuracy of dose calculations. Dose calculation errors result from limitations of modern dose calculation algorithms in modeling metal/tissue interface effects. Metals also cause streak artifacts in the computed tomography (CT) images that are used for treatment planning, and these artifacts can also degrade dose calculation accuracy. Metal based-energy deposition kernels are a potential solution for the calculation errors associated with the limitations of the convolution/superposition (C/S) dose calculation method as they better model photon interactions and scatter in …

Methylation Of Egfr By Arginine Methyltransferase Prmt1 Enhances Egfr Signaling And Cetuximab Resistance, Hsin-Wei Liao

Dissertations and Theses (Open Access)

Protein modifications of epidermal growth factor receptor (EGFR) intracellular domain are well known regulators of EGFR functions whereas those of its extracellular domain remain relatively unexplored. Here, we report that methylation at R198 and R200 of EGFR extracellular domain by protein arginine methyltransferase 1 (PRMT1) upregulates its binding to EGF and subsequent receptor dimerization and signaling activation. Methylation-defective EGFR mutant reduced tumor growth in mouse orthotopic xenograft model. Importantly, increased EGFR methylation sustains its signaling activation and cell proliferation in the presence of therapeutic EGFR monoclonal antibody, cetuximab. EGFR methylation level also correlates with higher recurrence rate after cetuximab treatment …

Prophylactic Cranial Irradiation Reduces The Incidence Of Brain Metastasis In A Mouse Model Of Metastatic Breast Cancer, Daniel L. Smith

Dissertations and Theses (Open Access)

Prophylactic cranial irradiation (PCI) is a preventative whole-brain irradiation technique used to reduce the incidence of brain metastasis and improve overall survival in select patients with small cell lung cancer and acute lymphoblastic leukemia. A population of breast cancer patients – stage IV, HER2+ or triple-negative – has emerged as having a high risk of developing brain metastases. Because only 10-20% of breast cancer patients diagnosed with brain metastases survive longer than one year, in this high-risk population the benefit of PCI – potential for reduced incidence of brain metastasis and improved overall survival – may outweigh the risks – …

Metabolic Profiling Of Prions In The Gastro-Intestinal Tract, Uffaf Khan

Dissertations and Theses (Open Access)

Metabolic profiling of prions in the gastro-intestinal tract

Uffaf Khan, B.S.

Thesis Advisor: Claudio Soto, Ph.D.

Abstract

Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), are a group of debilitating neurodegenerative disorders that affect both humans and animals. They can be spread by horizontal transmission as seen in chronic wasting disease in deer and elk population. In addition, transmission to humans has also been documented which includes bovine spongiform encephalopathy in cattle to variant Creutzfeldt-Jakob disease in humans due to consumption of contaminated meat. The most probable natural route of transmission is by oral consumption of infectious material. Even …

Ankyrin-B And Mtor Complex 1 In The Regulation Of Electrical Activities In The Heart, Henry C. Wu, Henry C. Wu

Dissertations and Theses (Open Access)

The mammalian target of rapamycin complex 1 (mTORC1) activity is paramount in the regulation of electrical activities in the brain and the heart. In the brain, the tumor suppressor gene TSC2 encodes the protein product tuberin that interacts with hamartin to form a heterodimer Tuberous Sclerosis Complex (TSC) that regulates mTORC1. When TSC2 is disrupted, mTORC1 activity becomes dysregulated resulting in abnormal electrical activities in the brain manifesting in the form of epileptic seizures. In the heart, mTORC1 activity is triggered by a sustained increase in hemodynamic pressure causing the heart to electrically remodel. A likely candidate serving as the …

Antidepressant Effects In Hybrid Striped Bass: Moving From External Exposures To Internal Doses, Lauren Sweet

All Dissertations

Over 47 percent of Americans take at least one prescription drug per month and of these pharmaceuticals, antidepressants are the third most prescribed drug. Their widespread and prolonged use coupled with incomplete removal during wastewater treatment processes has made them one of the most commonly detected pharmaceuticals in the aquatic environment. Antidepressants are intended to modify human behavior by altering brain chemistry and the neurotransmitter receptor targets of these chemicals are highly conserved in many vertebrate species; thus, aquatic organisms may be at risk. Previous research in our lab has shown that exposure of hybrid striped bass (HSB) (Morone saxatilis …

Adverse Effects Of Asparaginase In Pediatric Patients With Acute Lymphoblastic Leukemia, Chengcheng Liu

Theses and Dissertations (ETD)

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer. Asparaginase is a critical treatment component for ALL. However, its use is complicated by adverse effects, such as hypersensitivity, osteonecrosis and pancreatitis.

Hypersensitivity to asparaginase typically requires discontinuation of current formulation and substitution with other formulations, but the differential diagnosis can be challenging, and the diagnostic utility of antibody tests is unclear. We comprehensively analyzed anti-Elspar (native E.coli asparaginase) IgG antibodies in 410 pediatric patients treated on an asparaginaseintensive front-line clinical trial. Of 169 patients (41.2%) who exhibited clinical allergy, 147 (87.0%) were positive for anti-Elspar antibody. Of …

Mechanisms Of Immunological Tolerance In Central Nervous System Inflammatory Demyelination., Elisabeth R. Mari, Jason N. Moore, Guang-Xian Zhang, A. M. Rostami

Department of Neurology Faculty Papers

Multiple sclerosis is a complex autoimmune disease of the central nervous system that results in a disruption of the balance between pro-inflammatory and anti-inflammatory signals in the immune system. Given that central nervous system inflammation can be suppressed by various immunological tolerance mechanisms, immune tolerance has become a focus of research in the attempt to induce long-lasting immune suppression of pathogenic T cells. Mechanisms underlying this tolerance induction include induction of regulatory T cell populations, anergy and the induction of tolerogenic antigen-presenting cells. The intravenous administration of encephalitogenic peptides has been shown to suppress experimental autoimmune encephalomyelitis and induce tolerance …

Effects Of Pelvis Impact Angle And Hip Muscle Forces On Hip Fracture Risk During A Fall Using An Advanced Hip Impact Simulator, Woochol J. Choi, Stephen N. Robinovitch

Physical Therapy Faculty Articles and Research

"Over 90% of hip fractures in older adults are caused by falls [1]. Whether a given fall will cause hip fracture depends on bone strength, and on the impact force and stress applied to the bone during impact [2]. Improved understanding is required on how peak bone stresses during a fall depend on the mechanics of a fall, and on the state of contraction at the moment of impact of the muscles spanning the hip. Recently, Choi et al showed that, for lateral impact to the hip, peak stresses decrease with increases in hip abductor muscle force [3]. In the …

Influence Of Pelvis Impact Angle During A Fall: On The Protective Benefit Of Hip Protectors, Woochol J. Choi, Stephen N. Robinovitch

Physical Therapy Faculty Articles and Research

"Over 90% of hip fractures are due to falls [1]. Laboratory measures have shown that wearable hip protectors reduce impact forces to the proximal femur during a simulated sideways fall on the hip [2, 3]. However, clinical evidence suggests that hip fractures still occur when hip protectors are worn [4]. Furthermore, while falls in real life result in a variety of impact configurations, biomechanical tests to date have focused only on lateral impact to the pelvis. In the current study, we examined how the force reduction provided by wearable hip protectors is affected by pelvis impact configuration during simulated sideways …

The Adaptive Change Of Hla-Drb1 Allele Frequencies Caused By Natural Selection In A Mongolian Population That Migrated To The South Of China, Hao Sun, Zhaoqing Yang, Keqin Lin, Shuyuan Liu, Kai Huang, Xiuyun Wang, Jiayou Chu, Xinyu Huang

Faculty Publications

Pathogen-driven balancing selection determines the richness of human leukocyte antigen (HLA) alleles. Changes in the pathogen spectrum may cause corresponding changes in HLA loci. Approximately 700 years ago, a Mongolian population moved from the north of China to the Yunnan region in the south of China. The pathogen spectrum in the south of China differs from that in the north. In this study, changes in the HLA genes in the Yunnan Mongolian population, as well as the underlying mechanism, were investigated. A sequence-based typing method (SBT) was used to genotype HLA-DRB1 in 470 individuals from two Mongolian populations and another …

Myricetin Inhibits Proliferation Of Cisplatin-Resistant Cancer Cells Through A P53-Dependent Apoptotic Pathway, Haizhi Huang, Allen Y. Chen, Xingqian Ye, Bingyun Li, Yon Rojanasakul, Gary O. Rankin, Yi Charlie Chen

Pharmaceutical Science and Research

Cisplatin is a commonly used drug for cancer treatment by crosslinking DNA, leading to apoptosis of cancer cells, resistance to cisplatin treatment often occurs, leading to relapse. Therefore, there is a need for the development of more effective treatment strategies that can overcome chemoresistance. Myricetin is a flavonoid from fruits and vegetables, showing anticancer activity in various cancer cells. In this study, we found myricetin exhibited greater cytotoxicity than cisplatin in two cisplatin-resistant ovarian cancer cell lines, OVCAR-3 and A2780/CP70, and it was less cytotoxic to the normal ovarian cell line IOSE-364. Myricetin selectively induced apoptosis in both cisplatin-resistant cancer …

Selective Generation Of Dopaminergic Precursors From Mouse Fibroblasts By Direct Lineage Conversion., Changhai Tian, Yuju Li, Yunlong Huang, Yongxiang Wang, Dapeng Chen, Jinxu Liu, Xiaobei Deng, Lijun Sun, Kristi Anderson, Xinrui Qi, Yulong Li, R. Lee Mosley, Xiangmei Chen, Jian Huang, Jialin C. Zheng

Journal Articles: Pharmacology & Experimental Neuroscience

Degeneration of midbrain dopaminergic (DA) neurons is a key pathological event of Parkinson's disease (PD). Limited adult dopaminergic neurogenesis has led to novel therapeutic strategies such as transplantation of dopaminergic precursors (DPs). However, this strategy is currently restrained by a lack of cell source, the tendency for the DPs to become a glial-restricted state, and the tumor formation after transplantation. Here, we demonstrate the direct conversion of mouse fibroblasts into induced DPs (iDPs) by ectopic expression of Brn2, Sox2 and Foxa2. Besides expression with neural progenitor markers and midbrain genes including Corin, Otx2 and Lmx1a, the iDPs were restricted to …

Reversal Of Aging-Related Neuronal Ca2+ Dysregulation And Cognitive Impairment By Delivery Of A Transgene Encoding Fk506-Binding Protein 12.6/1b To The Hippocampus, John C. Gant, Kuey-Chu Chen, Inga Kadish, Eric M. Blalock, Olivier Thibault, Nada M. Porter, Philip W. Landfield

Pharmacology and Nutritional Sciences Faculty Publications

Brain Ca(2+) regulatory processes are altered during aging, disrupting neuronal, and cognitive functions. In hippocampal pyramidal neurons, the Ca(2+)-dependent slow afterhyperpolarization (sAHP) exhibits an increase with aging, which correlates with memory impairment. The increased sAHP results from elevated L-type Ca(2+) channel activity and ryanodine receptor (RyR)-mediated Ca(2+) release, but underlying molecular mechanisms are poorly understood. Previously, we found that expression of the gene encoding FK506-binding protein 12.6/1b (FKBP1b), a small immunophilin that stabilizes RyR-mediated Ca(2+) release in cardiomyocytes, declines in hippocampus of aged rats and Alzheimer's disease subjects. Additionally, knockdown/disruption of hippocampal FKBP1b in young rats augments neuronal Ca(2+) responses. …

Amikacin Concentrations Predictive Of Ototoxicity In Multidrug-Resistant Tuberculosis Patients, Chawangwa Modongo, Jotam G. Pasipanodya, Nicola M. Zetola, Scott M. Williams

Dartmouth Scholarship

Aminoglycosides, such as amikacin, are used to treat multidrug-resistant tuberculosis. However, ototoxicity is a common problem and is monitored using peak and trough amikacin concentrations based on World Health Organization recommendations. Our objective was to identify clinical factors predictive of ototoxicity using an agnostic machine learning method. We used classification and regression tree (CART) analyses to identify clinical factors, including amikacin concentration t

hresholds that pre- dicted audiometry-confirmed ototoxicity among 28 multidrug-resistant pulmonary tuberculosis patients in Botswana. Amika- cin concentrations were measured for all patients. The quantitative relationship between predictive factors and the probability of ototoxicity were then identified using …

Week Of July 27, 2015, New York Medical College

InTouch

• Public Health Program Passes the Test... with Flying Colors
• School of Medicine Class of 2017 Transitions to the Clinical Years
• NYMC Hosts 16th Pediatric Cancer Research Foundation Memorial Lectureship
• NYMC Reaches Out to Nepal
• NYMC Hosts Open Door Family Medical Centers Summer Students
• Lawrence Shapiro, M.D., Is Named Professor Emeritus of Pediatrics

Halting The Hallmarks: A Cellular Automaton Model Of Early Cancer Growth Inhibition, Jenna Butler, Frances Mackay, Colin Denniston, Mark Daley

Brain and Mind Institute Researchers' Publications

Cancer treatment is a fragmented and varied process, as ‘‘cancer’’ is really hundreds of different diseases. The ‘‘hallmarks of cancer’’ proposed by Hanahan and Weinberg (Cell 100(1):57–70, 2000) are a framework for viewing cancer within a common set of underlying principles—ten properties that are common to almost all cancers, allowing them to grow uncontrollably and ravage the body. We used a cellular automaton model of tumour growth paired with lattice Boltzmann methods modelling oxygen flow to simulate combination drugs targeted at knocking out pairs of hallmarks. We found that knocking out some pairs of cancer-enabling hallmarks did not prevent tumour …

Gallic Acid, A Phenolic Compound, Exerts Anti-Angiogenic Effects Via The Pten/Akt/Hif-1Α/Vegf Signaling Pathway In Ovarian Cancer Cells, Zhiping He, Allen Y. Chen, Yon Rojanasakul, Gary O. Rankin, Yi Charlie Chen

Pharmaceutical Science and Research

Gallic acid (GA), a polyphenol, is widely found in numerous fruits and vegetables, particularly in hickory nuts. In the present study, we found that gallic acid, a natural phenolic compound isolated from fruits and vegetables, had a more potent growth inhibitory effect on two ovarian cancer cell lines, OVCAR-3 and A2780/CP70, than the effect on a normal ovarian cell line, IOSE-364. These results demonstrated that GA selectively inhibits the growth of cancer cells. Gene expression was examined by ELISA and western blot analysis, and gene pathways were examined by luciferase assay. It was found that GA inhibited VEGF secretion and …

Compassionate Use Of Experimental Therapies: Who Should Decide?, Patricia J. Zettler

Faculty Publications By Year

In addition to being an example of unsubstantiated hype about regenerative medicine, the controversy around the Italy-based Stamina Foundation's unproven stem cell therapy represents another chapter in a continuing debate about how to balance patients' requests for early access to experimental medicines with requirements for demonstrating safety and effectiveness. Compassionate use of the Stamina therapy arguably should not have been permitted under Italy's laws, but public pressure was intense and judges ultimately granted access. One lesson from these events is that expert regulatory agencies may be the institutions most competent to make compassionate use decisions and that policies should include …

Sex Hormone-Dependent Trna Halves Enhance Cell Proliferation In Breast And Prostate Cancers., Shozo Honda, Phillipe Loher, Megumi Shigematsu, Juan P. Palazzo, Ryusuke Suzuki, Issei Imoto, Isidore Rigoutsos, Yohei Kirino, Phd

Computational Medicine Center Faculty Papers

Sex hormones and their receptors play critical roles in the development and progression of the breast and prostate cancers. Here we report that a novel type of transfer RNA (tRNA)-derived small RNA, termed Sex HOrmone-dependent TRNA-derived RNAs (SHOT-RNAs), are specifically and abundantly expressed in estrogen receptor (ER)-positive breast cancer and androgen receptor (AR)-positive prostate cancer cell lines. SHOT-RNAs are not abundantly present in ER(-) breast cancer, AR(-) prostate cancer, or other examined cancer cell lines from other tissues. ER-dependent accumulation of SHOT-RNAs is not limited to a cell culture system, but it also occurs in luminal-type breast cancer patient tissues. …

Cellular Prostatic Acid Phosphatase (Cpacp) Serves As A Useful Biomarker Of Histone Deacetylase (Hdac) Inhibitors In Prostate Cancer Cell Growth Suppression., Yu-Wei Chou, Fen-Fen Lin, Sakthivel Muniyan, Frank C. Lin, Ching-Shih Chen, Jue Wang, Chao-Cheng Huang, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: Prostate cancer (PCa) is the most commonly diagnosed solid tumor and the second leading cancer death in the United States, and also one of the major cancer-related deaths in Chinese. Androgen deprivation therapy (ADT) is the first line treatment for metastatic PCa. PCa ultimately relapses with subsequent ADT treatment failure and becomes castrate-resistant (CR). It is important to develop effective therapies with a surrogate marker towards CR PCa.

METHOD: Histone deacetylase (HDAC) inhibitors were examined to determine their effects in androgen receptor (AR)/cellular prostatic acid phosphatase (cPAcP)-positive PCa cells, including LNCaP C-33, C-81, C4-2 and C4-2B and MDA PCa2b …

Amp-Activated Protein Kinase Directly Phosphorylates And Destabilizes Hedgehog Pathway Transcription Factor Gli1 In Medulloblastoma, Yen-Hsing Li, Jia Luo, Yung-Yi C. Mosley, Victoria E. Hedrick, Lake N. Paul, Julia Chang, Guangjun Zhang, Yu-Kuo Wang, Max R. Banko, Anne Brunet, Shihuan Kuang, Jen-Leih Wu, Chun-Ju Chang, Matthew P. Scott, Jer-Yen Yang

Department of Basic Medical Sciences Faculty Publications

The Hedgehog (Hh) pathway regulates cell differen- tiation and proliferation during development by controlling the Gli transcription factors. Cell fate de- cisions and progression toward organ and tissue maturity must be coordinated, and how an energy sensor regulates the Hh pathway is not clear. AMP- activated protein kinase (AMPK) is an important sensor of energy stores and controls protein synthe- sis and other energy-intensive processes. AMPK is directly responsive to intracellular AMP levels, inhib- iting a wide range of cell activities if ATP is low and AMP is high. Thus, AMPK can affect development by influencing protein synthesis and other …

Nos Inhibition Modulates Immune Polarization And Improves Radiation-Induced Tumor Growth Delay, Lisa A. Ridnour, Robert Y.S. Cheng, Jonathan M. Weiss, Sukhbir Kaur, David R. Soto-Pantoja, Debashree Basudhar, Julie L. Heinecke, C. Andrew Stewart, William Degraff, Anastasia L. Sowers, Angela Thetford, Aparna H. Kesarwala, David D. Roberts, Howard A. Young, James B. Mitchell, Giorgio Trinchieri, Robert H. Wiltrout, David A. Wink

United States Public Health Resources

Nitric oxide synthases (NOS) are important mediators of progrowth signaling in tumor cells, as they regulate angiogenesis, immune response, and immune-mediated wound healing. Ionizing radiation (IR) is also an immune modulator and inducer of wound response. We hypothesized that radiation therapeutic efficacy could be improved by targeting NOS following tumor irradiation. Herein, we show enhanced radiation-induced (10 Gy) tumor growth delay in a syngeneic model (C3H) but not immunosuppressed (Nu/Nu) squamous cell carcinoma tumor-bearing mice treated post-IR with the constitutive NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME). These results suggest a requirement of T cells for improved radiation tumor response. In …

Zbtb20 Is A Sequence-Specific Transcriptional Repressor Of Alpha-Fetoprotein Gene, Hai Zhang, Dongmei Cao, Luting Zhou, Ye Zhang, Xiaoqin Guo, Hui Li, Yuxia Chen, Brett T. Spear, Jia-Wei Wu, Zhifang Xie, Weiping J Zhang

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Alpha-fetoprotein (AFP) represents a classical model system to study developmental gene regulation in mammalian cells. We previously reported that liver ZBTB20 is developmentally regulated and plays a central role in AFP postnatal repression. Here we show that ZBTB20 is a sequence-specific transcriptional repressor of AFP. By ELISA-based DNA-protein binding assay and conventional gel shift assay, we successfully identified a ZBTB20-binding site at -104/-86 of mouse AFP gene, flanked by two HNF1 sites and two C/EBP sites in the proximal promoter. Importantly, mutation of the core sequence in this site fully abolished its binding to ZBTB20 in vitro, as well …

B Lymphocytes Are Required During The Early Priming Of Cd4+ T Cells For Clearance Of Pneumocystis Infection In Mice, Michael M. Opata, Melissa L. Hollifield, Frances E. Lund, Troy D. Randall, Robert Dunn, Beth A. Garvy, David J. Feola

Microbiology, Immunology, and Molecular Genetics Faculty Publications

B cells play a critical role in the clearance of Pneumocystis. In addition to production of Pneumocystis-specific Abs, B cells are required during the priming phase for CD4⁺ T cells to expand normally and generate memory. Clearance of Pneumocystis was found to be dependent on Ag specific B cells and on the ability of B cells to secrete Pneumocystis-specific Ab, as mice with B cells defective in these functions or with a restricted BCR were unable to control Pneumocystis infection. Because Pneumocystis-specific antiserum was only able to partially protect B cell–deficient mice from infection, we …

Dna-Pkcs-Mediated Transcriptional Regulation Drives Prostate Cancer Progression And Metastasis., Jonathan F Goodwin, Vishal Kothari, Justin M Drake, Shuang Zhao, Emanuela Dylgjeri, Jeffry L. Dean, Matthew J. Schiewer, Christopher Mcnair, Jennifer K. Jones, Alvaro Aytes, Michael S. Magee, Adam E. Snook, Ziqi Zhu, Robert Den, Ruth C. Birbe, Leonard G. Gomella, Nicholas A. Graham, Ajay A. Vashisht, James A. Wohlschlegel, Thomas G. Graeber, R. Jeffrey Karnes, Mandeep Takhar, Elai Davicioni, Scott A. Tomlins, Cory Abate-Shen, Nima Sharifi, Owen N. Witte, Felix Y. Feng, Karen E. Knudsen

Department of Cancer Biology Faculty Papers

Emerging evidence demonstrates that the DNA repair kinase DNA-PKcs exerts divergent roles in transcriptional regulation of unsolved consequence. Here, in vitro and in vivo interrogation demonstrate that DNA-PKcs functions as a selective modulator of transcriptional networks that induce cell migration, invasion, and metastasis. Accordingly, suppression of DNA-PKcs inhibits tumor metastases. Clinical assessment revealed that DNA-PKcs is significantly elevated in advanced disease and independently predicts for metastases, recurrence, and reduced overall survival. Further investigation demonstrated that DNA-PKcs in advanced tumors is highly activated, independent of DNA damage indicators. Combined, these findings reveal unexpected DNA-PKcs functions, identify DNA-PKcs as a potent driver …

Regulated Phosphorylation Of The K-Cl Cotransporter Kcc3 Is A Molecular Switch Of Intracellular Potassium Content And Cell Volume Homeostasis, Norma C. Adragna, Nagendra B. Ravilla, Peter K. Lauf, Gulnaz Begum, Arjun R. Khanna, Dandan Sun, Kristopher K. Kahle

Pharmacology and Toxicology Faculty Publications

The defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K+ and Cl− efflux via activation of K+ channels, volume-regulated anion channels (VRACs), and the K+-Cl− cotransporters, including KCC3. Here, we show genetic alanine (Ala) substitution at threonines (Thr) 991 and 1048 in the KCC3a isoform carboxyl-terminus, preventing inhibitory phosphorylation at these sites, not only significantly up-regulates KCC3a activity up to 25-fold in normally inhibitory isotonic conditions, but is also accompanied by reversal of activity of the …

Mir-21 In Extracellular Vesicles Leads To Neurotoxicity Via Tlr7 Signaling In Siv Neurological Disease., Sowmya V. Yelamanchili, Benjamin G. Lamberty, Deborah A. Rennard, Brenda M. Morsey, Colleen G. Hochfelder, Brittney M. Meays, Efrat Levy, Howard S. Fox

Journal Articles: Pharmacology & Experimental Neuroscience

Recent studies have found that extracellular vesicles (EVs) play an important role in normal and disease processes. In the present study, we isolated and characterized EVs from the brains of rhesus macaques, both with and without simian immunodeficiency virus (SIV) induced central nervous system (CNS) disease. Small RNA sequencing revealed increased miR-21 levels in EVs from SIV encephalitic (SIVE) brains. In situ hybridization revealed increased miR-21 expression in neurons and macrophage/microglial cells/nodules during SIV induced CNS disease. In vitro culture of macrophages revealed that miR-21 is released into EVs and is neurotoxic when compared to EVs derived from miR-21-/- knockout …

Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green

Dartmouth Scholarship

Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.

Toll-Like Receptors And Dectin-1, A C-Type Lectin Receptor, Trigger Divergent Functions In Cns Macrophages, John C. Gensel, Yan Wang, Zhen Guan, Kyle A. Beckwith, Kaitlyn J. Braun, Ping Wei, Dana M. Mctigue, Phillip G. Popovich

Spinal Cord and Brain Injury Research Center Faculty Publications

Spinal cord injury (SCI) activates macrophages, endowing them with both reparative and pathological functions. The mechanisms responsible for these divergent functions are unknown but are likely controlled through stochastic activation of different macrophage receptor subtypes. Various danger-associated molecular patterns released from dying cells in the injured spinal cord likely activate distinct subtypes of macrophage pattern recognition receptors, including bacterial toll-like receptors (TLRs) and fungal C-type lectin receptors (e.g., dectin-1). To determine the in vivo consequences of activating these receptors, ligands specific for TLR2 or dectin-1 were microinjected, alone or in combination, into intact spinal cord. Both ligands elicit a florid …