Oligodendrocyte progenitors are highly sensitive to oxidative insults. Among the factors postulated to contribute to this susceptibility are high levels of intracellular iron and low antioxidant content. During ischemia, the neurotransmitter dopamine (DA) is released and may contribute to oxidative stress and oligodendrocyte injury in the hypomyelinating disorder, periventricular leucomalacia (PVL). In this thesis, I investigated the role of iron in DA-induced toxicity in primary cultures of oligodendrocyte progenitors, and assessed the contribution of the antioxidant defenses (glutathione (GSH), glutathione peroxidase (GPx) and superoxide dismutase (SOD)) and other survival factors (heat shock proteins and the protein kinase Akt) in determining the response of the cells to DA. / Addition of iron to cultures increased DA-induced expression of the stress protein heme oxygenase-1 (HO-1), and toxicity as assessed by mitochondrial activity, cellular release of lactate dehydrogenase, nuclear condensation and caspase-3 activation. In contrast, an iron chelator reduced these events. Furthermore, DA induced accumulation of superoxide, which was also reduced by the iron chelator. Surprisingly, a mimetic of the superoxide detoxifying enzyme, SOD potentiated DA toxicity, suggesting that generation of hydrogen peroxide via superoxide dismutation may be contributing to toxicity. Both a mimetic of the peroxide-scavenging enzyme, GPx and a GSH analog blocked DA-induced superoxide accumulation, HO-1 expression and caspase-3 activation. In addition, the GPx mimetic blocked caspase-3 activation induced by the combination of DA with iron. In contrast, an inhibitor of glutathione synthesis potentiated DA-induced HO-1 expression and cell death. / Finally, in further examining the cellular defense mechanisms, I found that various heat shock proteins increased in expression levels during oligodendroglial differentiation, however only heat shock protein-90 (HSP-90) was detected in oligodendrocyte progenitors. An HSP-90 inhibitor decreased activated Akt levels, induced caspase-3 activation, increased nuclear condensation, reduced oligodendrocyte progenitor viability, and potentiated DA-induced apoptosis. In addition, an Akt inhibitor alone exacerbated DA toxicity and in combination with the HSP-90 inhibitor caused synergistic potentiation of DA toxicity by enhancing caspase-3 activation. / In conclusion, elevated levels of iron, superoxide, deficient detoxification of peroxides by glutathione peroxidase and inadequate defense by glutathione contribute to the susceptibility of oligodendrocyte progenitors to DA-induced toxicity. On the other hand, HSP-90 alone or in concert with Akt play important roles in oligodendrocyte progenitors survival following an insult that produces oxidative stress.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.

Writer, eraser, and reader proteins are three classes of proteins/enzymes that add, remove, and recognize post-translational modifications (PTMs) on histone tails, respectively. The orchestrated action of these protein classes controls dynamic state of chromatin and influences gene expression. Dysregulation of these proteins are often associated with disease conditions. All three classes are targeted with small molecule inhibitors for various disease conditions. This is a promising area of research to develop therapeutics for various clinical conditions. I worked on a methyllysine reader protein Cbx7, which belong to polycomb group of proteins. Cbx7 is a chromodomain containing protein and it uses its chromodomain to recognize methyllysine partners such as H3K27me3. Aberrant expression of Cbx7 is observed in several cancers including prostate, breast, colon, thyroid, etc. Hence targeting Cbx7 with potent and selective inhibitors would be beneficial for therapeutic intervention for Cbx7 associated diseases. Here I report my work on design, synthesis, and evaluation of Cbx7 inhibitors. In my work, we identified several potent and selective inhibitors for Cbx7 and we published first-in-class antagonists for Cbx7. Few of these inhibitors were tested on cancer stem cell models. Further, I propose future work for targeting Cbx7 and other chromodomain containing proteins. / Graduate / 2018-09-04

Ketamine and phencyclidine (PCP) are noncompetitive antagonists of the N-methyl-D-aspartate (NMDA) type of ligand-gated glutamate receptors. Both agents have high abuse liability, and may produce dependence. Tolerance to the reinforcing effects of drugs of abuse is widely regarded as a key component of the dependence process. Therefore, the present study was conducted to examine whether tolerance develops to the reinforcing effects of ketamine, and whether PCP and dizocilpine, a noncompetitive NMDA antagonist with negligible abuse liability, produce cross-tolerance to the reinforcing effects of ketamine. Further, identification of the neural mechanisms that underlie tolerance to the reinforcing effects of drugs may yield information regarding drug dependence.

Hyperactivity is thought to be associated with an alteration of dopamine (DA) neurochemistry in brain. This conventional view became solidified on the basis of observed hyperactivity in DA-lesioned animals and effectiveness of the dopaminomimetics such as amphetamine (AMP) in abating hyperactivity in humans and in animal models of hyperactivity. However, because AMPreleases serotonin (5-HT) as well as DA, we investigated the potential role of 5-HT in an animal model of hyperactivity. We found that a greater intensity of hyperactivity was produced in rats when both DA and 5-HT neurons were damaged at appropriate times in ontogeny. Therefore, previously we proposed this as an animal model of attention deficit hyperactivity disorder (ADHD) - induced by destruction of dopaminergic neurons with 6-hydroxydopamine (6-OHDA (neonatally) and serotoninergic neurons with 5,7-dihydroxytryptamine (5,7-DHT) (in adulthood). In this model effects similar to that of AMP(attenuation of hyperlocomotion) were produced by m-chlorophenylpiperazine (m-CPP) but not by 1-phenylbiguanide (1-PG), respective 5-HT2 and 5-HT3 agonists. The effect of m-CPP was shown to be replicated by desipramine, and was largely attenuated by the 5-HT2 antagonist mianserin. These findings implicate 5-HT neurochemistry as potentially important therapeutic targets for treating human hyperactivity and possibly childhood ADHD.

No description available.

Parkash Amarender. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 158-172). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Table of contents --- p.ii / Abstract --- p.xi / 撮要 --- p.xiv / List of Abbreviations --- p.xvi / List of Tables --- p.xvii / List of Figures --- p.xix / Chapter CHAPTER 1. --- INTRODUCTION / Chapter 1.1 --- Ribosome-inactivating proteins (RIPs) --- p.3 / Chapter 1.2 --- General Properties of RIPs --- p.5 / Chapter 1.2.1 --- Structure --- p.5 / Chapter 1.2.1.1 --- Type I and Type II RIPs --- p.5 / Chapter 1.2.1.2 --- Small RIPs --- p.10 / Chapter 1.2.2 --- Distribution --- p.12 / Chapter 1.2.3 --- Physicochemical properties --- p.15 / Chapter 1.3 --- Enzymatic activities of RIPs --- p.17 / Chapter 1.3.1 --- N-glycosidase activity --- p.17 / Chapter 1.3.2 --- Polynucleotide:adenosine glycosidase activity --- p.21 / Chapter 1.3.3 --- Ribonuclease (RNase) activity --- p.24 / Chapter 1.3.4 --- Deoxyribonucleolytic (DNase) activity --- p.25 / Chapter 1.3.5 --- Multiple depurination --- p.26 / Chapter 1.3.6 --- Inhibition of protein synthesis --- p.27 / Chapter 1.4 --- Biological activities of RIPs --- p.29 / Chapter 1.4.1 --- Interaction of ribosome-inactivating proteins with cells --- p.29 / Chapter 1.4.1.1 --- Internalization of type 1 ribosome-inactivating proteins --- p.29 / Chapter 1.4.1.2 --- Internalization of type 2 ribosome-inactivating proteins --- p.32 / Chapter 1.4.2 --- Effects on laboratory animals --- p.33 / Chapter 1.4.3 --- Immunosuppressive activity --- p.33 / Chapter 1.4.4 --- Abortifacient activity --- p.34 / Chapter 1.4.5 --- Antiviral activity --- p.35 / Chapter 1.5 --- Physiological roles of RIPs --- p.37 / Chapter 1.6 --- Applications of RIPs --- p.39 / Chapter 1.6.1 --- Possible uses in experimental and clinical medicine --- p.39 / Chapter 1.6.1.1 --- Anti-tumor therapy --- p.40 / Chapter 1.6.1.2 --- Immune disorders --- p.42 / Chapter 1.6.1.3 --- Neuroscience research --- p.43 / Chapter 1.6.2 --- Applications in agriculture --- p.44 / Chapter 1.7 --- Arginine/Glutamate Rich Polypeptides (AGRPs) --- p.46 / Chapter 1.8 --- Objectives of the present study --- p.48 / Chapter 1.8.1 --- Rationale of the study --- p.48 / Chapter 1.8.2 --- Outline of the thesis --- p.50 / Chapter Chapter 2 --- Materials and methods / Chapter 2.1 --- Introduction --- p.52 / Chapter 2.2 --- Materials and methods --- p.54 / Chapter 2.2.1 --- Materials --- p.54 / Chapter 2.2.2 --- Preparation of crude extract --- p.55 / Chapter 2.2.3 --- Purification of proteins --- p.55 / Chapter 2.2.4 --- Molecular weight determination with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) --- p.61 / Chapter 2.2.5 --- Protein determination --- p.64 / Chapter 2.2.6 --- N-terminal amino acid sequence --- p.64 / Chapter 2.2.7 --- Preparation of rabbit reticulocyte lysate --- p.65 / Chapter 2.2.8 --- Assay for cell-free protein synthesis- inhibiting activity --- p.65 / Chapter 2.2.9 --- Assay for N-glycosidase activity --- p.66 / Chapter 2.2.10 --- Assay for ribonuclease activity --- p.70 / Chapter 2.2.11 --- Assay for antifungal activity --- p.71 / Chapter 2.2.12 --- Assay for dehydrogenase activity --- p.71 / Chapter Chapter 3 --- Purification and characterization of proteins from their respective sources. / Chapter 3.1. --- Purification and Characterization of Hispidin from Hairy melon (Benincasa hispida var. chieh-qua) / Chapter 3.1.1. --- Introduction --- p.73 / Chapter 3.1.2. --- Results --- p.76 / Chapter 3.1.2.1. --- Purification --- p.78 / Chapter 3.1.2.2. --- Molecular weight determination --- p.84 / Chapter 3.1.2.3. --- N-terminal amino acid sequence --- p.85 / Chapter 3.1.2.4. --- Assay for cell-free protein synthesis-inhibiting activity --- p.86 / Chapter 3.1.2.5. --- Assay for N-glycosidase activity --- p.87 / Chapter 3.1.2.6. --- Assay for ribonuclease activity --- p.88 / Chapter 3.1.2.7. --- Assay for dihydrodiol dehydrogenase activity --- p.88 / Chapter 3.1.2.8. --- Assay for antifungal activity --- p.89 / Chapter 3.1.2.9. --- "Assessment of purity, yield and activity" --- p.91 / Chapter 3.1.3. --- Discussion --- p.92 / Chapter 3.2. --- Purification and Characterization of Momorchin from Dried Bitter Gourd (Momordica charantia) Seeds / Chapter 3.2.1. --- Introduction --- p.95 / Chapter 3.2.2. --- Results --- p.99 / Chapter 3.2.2.1. --- Purification --- p.100 / Chapter 3.2.2.2. --- Molecular weight determination --- p.103 / Chapter 3.2.2.3. --- N-terminal amino acid sequence --- p.104 / Chapter 3.2.2.4. --- Assay for cell-free protein synthesis- inhibiting activity --- p.105 / Chapter 3.2.2.5. --- Assay for ribonuclease activity --- p.105 / Chapter 3.2.2.6. --- Assay for N-glycosidase activity --- p.106 / Chapter 3.2.2.7. --- "Assessment of purity, yield and activity" --- p.107 / Chapter 3.2.3. --- Discussion --- p.108 / Chapter 3.3.3. --- Purification and Characterization of Luffacylin from Sponge Gourd (Luffa cylindrica) / Chapter 3.3.1. --- Introduction --- p.110 / Chapter 3.3.2. --- Results --- p.113 / Chapter 3.3.2.1. --- Purification --- p.115 / Chapter 3.3.2.2. --- Molecular weight determination --- p.119 / Chapter 3.3.2.3. --- N-terminal amino acid sequencing --- p.120 / Chapter 3.3.2.4. --- Assay for cell-free protein synthesis- inhibiting activity --- p.121 / Chapter 3.3.2.5. --- Assay for ribonuclease activity --- p.121 / Chapter 3.3.2.6. --- Assay for N-glycosidase activity --- p.122 / Chapter 3.3.2.7. --- Assay for antifungal activity --- p.123 / Chapter 3.3.2.8. --- "Assessment of purity, activity and yield" --- p.124 / Chapter 3.3.3. --- Discussion --- p.125 / Chapter 3.4. --- Purification and Characterization of α and β Benincasin from fresh Winter Melon {Benincasa hispida var. dong-gua) Seeds / Chapter 3.4.1. --- Introduction --- p.127 / Chapter 3.4.2. --- Results --- p.129 / Chapter 3.4.2.1. --- Purification --- p.130 / Chapter 3.4.2.2. --- Molecular weight determination --- p.135 / Chapter 3.4.2.3. --- N-terminal amino acid sequence --- p.136 / Chapter 3.4.2.4. --- Assay for cell-free protein synthesis- inhibiting activity --- p.137 / Chapter 3.4.2.5. --- Assay for ribonuclease activity --- p.137 / Chapter 3.4.2.6. --- Assay for antifungal activity --- p.138 / Chapter 3.4.2.7. --- "Assessment of purity, activity and yield" --- p.140 / Chapter 3.4.3. --- Discussion --- p.141 / Chapter 3.5. --- Purification and characterization of Moschins from Pumpkin (Cucurbita moschata) Seeds / Chapter 3.5.1. --- Introduction --- p.143 / Chapter 3.5.2. --- Results --- p.145 / Chapter 3.5.2.1. --- Purification --- p.146 / Chapter 3.5.2.2. --- Molecular weight determination --- p.149 / Chapter 3.5.2.3. --- N-terminal amino acid sequence --- p.150 / Chapter 3.5.2.4. --- Assay for cell-free protein synthesis- inhibiting activity --- p.151 / Chapter 3.5.2.5. --- Assay for ribonuclease activity --- p.151 / Chapter 3.5.2.6. --- "Assessment of purity, activity and yield" --- p.152 / Chapter 3.5.3. --- Discussion --- p.153 / Chapter Chapter 4 --- General Discussion and Conclusion --- p.154 / References --- p.158

Recent population studies provide evidence that individuals with high circulating insulin levels have a poor prognosis and/or increased risk of cancer development; however, laboratory studies concerning the role of insulin in breast cancer biology are sparse. We compared the growth of 4T1 murine breast cancer allografts in control mice, alloxan-induced hypoinsulinemic mice, and mice treated with the insulin/insulin-like growth factor-1 receptor tyrosine kinase inhibitor BMS-536924. Both interventions significantly decreased tumor growth versus control and decreased pathway activation downstream of the insulin receptor as reflected by Aktser473 phosphorylation status in the neoplastic tissue. Alloxan-treated mice exhibited signs of insulin deficiency, while BMS-536924-treated animals showed only minor metabolic derangements. Skeletal muscle displayed reduced pAktser473 in alloxan-treated mice. In contrast, BMS-536924 treatment increased pAktser473 in muscle. This raises the possibility that the relative lack of metabolic toxicity of BMS-536924 involves varying tissue levels of the drug. These results support the view that host insulin physiology is a potentially modifiable determinant of breast cancer behaviour.

Indiana University-Purdue University Indianapolis (IUPUI) / Protein-protein interactions play a crucial role in a wide range of biological processes. Research on the design and synthesis of small molecules to modulate these proteinprotein interactions can lead to new targets and drugs to modulate their function. In Chapter one, we discuss the design and synthesis of small molecules to probe a proteinprotein interaction in a voltage-gated Ca2+ channel. Virtual screening identified a compound (BTT-3) that contained a 3,4-dihydro-3,4’-pyrazole core. This compound had modest biological activity when tested in a fluorescence polarization (FP) assay. The synthetic route to BTT-3 consisted of six steps. In addition, analogs of BTT-3 were made for a structure-activity study to establish the importance of a carboxylate moiety. We also synthesized a biotinylated benzophenone photo-affinity probe and linked it to BTT-3 to identify additional protein targets of the compound. In Chapter two, small-molecule antagonists targeting uPA-uPAR protein-protein interaction are presented. A total of 500 commercially-available compounds were previously identified by virtual screening and tested by a FP assay. Three classes of compounds were found with biological activity. The first class of compounds contains pyrrolidone core structures represented by IPR- 1110, the second class has a novel pyrrolo[3,4-c]pyrazole ring system, represented by xv IPR-1283 and the last series had compounds with a 1,2-disubstituted 1,2- dihydropyrrolo[3,4-b]indol-3(4H)-one core structure, represented by IPR-540. Each of these three compounds were synthesized and assessed by FP and ELISA assays. A binding mode of IPR-1110 with uPA was subsequently proposed. Based on this binding mode, another 61 IPR-1110 derivatives were synthesized by us to illustrate the SAR activity. Analogs of the other two series were also synthesized.

No description available.