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Articles 211 - 240 of 278

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Tied Together: A Molecular Role For Tie1 In Angiopoietin Tie2 Signaling, Tom Cm Seegar Apr 2010

Tied Together: A Molecular Role For Tie1 In Angiopoietin Tie2 Signaling, Tom Cm Seegar

Theses and Dissertations

The primary function of the vascular system is the maintenance of oxygen homeostasis for all metazoan tissue. Angiogenesis, the remodeling and maintenance of new blood vessels from an existing vessel, is primarily controlled through the endothelial specific receptor tyrosine kinase Tie2, and the orphan receptor tyrosine kinase, Tie1. Although these receptors share highly conserved, genetic and biochemical analysis has shown these receptors have distinct and essential roles in angiogenesis. Tie2 activation typically results in vessel stability and quiescences and has further been shown to interact with all four sub-types of the angiopoietin signaling factors, Ang1-4. Conversely, Tie1 is involved in …


Role Of Jak/Stat Pathway In The Pathogenesis Of Breast Cancer, Qifang Zhang Feb 2010

Role Of Jak/Stat Pathway In The Pathogenesis Of Breast Cancer, Qifang Zhang

Theses and Dissertations

The Jak/Stat signaling cascade mediates cell proliferation, differentiation, survival, apoptosis and immune responses. Aberrant activation of this pathway mediates neoplastic transformation and abnormal growth of many malignancies including breast cancer, the most common cancer among women, and the second leading cause of cancer deaths in women in United States. The mechanism by which the Jak/Stat pathway modulates the pathogenesis of breast cancer is unclear. This dissertation elucidates roles of Jak/Stat members that mediate the pathogenesis of breast cancer. For these studies, we used 4T1 mouse mammary tumor cells as a model which mimics human breast cancer. First, we investigated the …


Biochemical Characterization Of Suppressor Of Ikk-Ε And Nak-Associated Protein 1, Jonathan Forbes Jan 2010

Biochemical Characterization Of Suppressor Of Ikk-Ε And Nak-Associated Protein 1, Jonathan Forbes

Theses and Dissertations

Innate immunity provides the first line of defense against invading pathogen by recognizing and mounting a response to the pathogenic challenge. Among the cellular mechanisms of the innate immune response, Toll-like receptor 3 (TLR3) recognizes viral dsRNA and signals subsequent production of type-I interferon. The TLR3:interferon signaling cascades contains a kinase complex composed of two kinases and a scaffold protein, NAK-associated protein 1 (NAP1). The role of NAP1 in modulating kinase activation or regulation is unknown. A key inhibitory protein identified in the TLR3:interferon pathway, silencer of inhibitor of κBα kinase ε (SIKE), blocks the activity of this kinase complex …


Ipla2Β, Alternative Splicing And Apoptosis Of Pancreatic Islets, Bhargavi Emani Jan 2010

Ipla2Β, Alternative Splicing And Apoptosis Of Pancreatic Islets, Bhargavi Emani

Theses and Dissertations

Ceramides are bioactive lipids that can promote splicing of apoptosis-related genes, including caspase 9 and BCL-x. A recent study demonstrated that expression of neutral sphingomyelinase (NSMase), an enzyme that hydrolyzes sphingomyelins to generate ceramide, is regulated by Group VIA phospholipase A2 (iPLA2β)-dependent mechanism during β-cell apoptosis. This prompted us to hypothesize that iPLA2 is upstream of ceramide generation in the process regulating splicing of apoptotic genes. To test this, Jurkat T cells were treated with the selective inhibitor of iPLA2β, bromoenol lactone (BEL), RNA was isolated and converted to cDNA, and caspase 9 and BCL-x mRNA viii species were amplified …


Influence Of Retinal States On The Development And Maintenance Of Retinofugal Projections, Duncan Morhardt Jan 2010

Influence Of Retinal States On The Development And Maintenance Of Retinofugal Projections, Duncan Morhardt

Theses and Dissertations

Vision provides a critical interface with the physical world. This work examines visual development and vision loss in mice to glean the influence of the retinal state on visual connections. I first assessed the impact of retinal activity on the eye-specific segregation of retinal afferents in the lateral geniculate nucleus (LGN) of young Gβ5 -/- mice. Gβ5 is the fifth member of the β subfamily of heterotrimeric G proteins. Gβ5 binds and stabilizes the R7 family of regulators of G-protein signaling (RGS), which accelerate Gi/o GTP hydrolysis. Gβ5 -/- mice, which lack R7RGS activity, have malformed synapses in the outer …


Cell-Cell Junction Signaling Regulating Dna Double-Strand Break Repair In Breast Cells, Sinduja Ethiraj Jan 2010

Cell-Cell Junction Signaling Regulating Dna Double-Strand Break Repair In Breast Cells, Sinduja Ethiraj

Theses and Dissertations

Genomic instability and acquisition of invasiveness through the basement membrane extracellular matrix (ECM) are two major processes for epithelial cell malignancy in breast cancer. DNA double-strand break repair (DSBR) is one of the processes that get misregulated during breast cancer progression. In addition, radiation induced breaks such as those induced during radiation therapy to treat breast cancer patients are repaired by DSBR, rendering this pathway relevant for therapy as well. DSBR can occur either by homologous recombination (HR) or non-homologous end-joining (NHEJ). HR is accepted as the more error-free pathway. HR is regulated by the cell cycle status such that …


The Regulation Of Alternative Splicing By Oncogenic Signaling Pathways., Jacqueline Shultz Sep 2009

The Regulation Of Alternative Splicing By Oncogenic Signaling Pathways., Jacqueline Shultz

Theses and Dissertations

In the presented study, we demonstrate that the alternative splicing of caspase 9 was dysregulated in a large percentage of NSCLC tumors and cell lines. These findings led to the hypothesis that survival pathways activated by oncogenic mutation regulated this mechanism. Indeed, the oncogenic PI3-Kinase/Akt pathway was demonstrated to regulate the alternative splicing of caspase 9. Further mechanistic studies demonstrate that multiple Akt isoforms can regulate the alternative splicing of caspase 9 in NSCLC. Akt was additionally shown to mediate the exclusion of the exon 3,4,5,6 cassette of caspase 9 via the phospho-state of the RNA trans-factor, SRp30a. Mutagenesis studies …


Lysophosphatidic Acid Is A Mediator Of Interleukin-6 Production In Ovarian Cancer Cells, David Dang Jul 2009

Lysophosphatidic Acid Is A Mediator Of Interleukin-6 Production In Ovarian Cancer Cells, David Dang

Theses and Dissertations

Lysophosphatidic acid (LPA) is a naturally occurring bioactive lysophospholipid that mediates a broad range of cellular processes such as cell proliferation, survival, migration and invasion. LPA also plays a potential role in human oncogenesis as suggested by elevated expression of its receptors and its producing enzymes in malignant tissues. In the current study, we demonstrated that LPA is a potent mediator of interleukin-6 (IL-6) production in ovarian cancer. IL-6 is a pleiotropic cytokine which is thought to be an important mediator of ovarian cancer development and progression. Here, we demonstrated that IL-6 levels are indeed increased in the plasma of …


The Regulation Of Platelet Activating Factor Acetylhydrolase By Oxidized Phospholipids, Rachael Griffiths Jul 2009

The Regulation Of Platelet Activating Factor Acetylhydrolase By Oxidized Phospholipids, Rachael Griffiths

Theses and Dissertations

Platelet-activating factor acetylhydrolase (PAFAH) is elevated in atherosclerosis and may play a role in pathogenesis of this disease. Molecular mechanisms regulating the expression of this lipoprotein-associated PLA2 are indistinct. Mildy oxidized low density lipoprotein (oxLDL) and monocytes (the primary source of PAFAH) are co-localized in early atheromas. Monocytes are activated by oxidized phospholipids (oxPL) in the oxLDL particle. We hypothesized that oxPL-activated monocytes are the source of increased levels of PAFAH in atherosclerosis. We found that PAFAH expression is significantly induced by OxPAPC and in particular long-chain fractions of oxPAPC in monocytes and cytokine-differentiated DC, but not cytokine-differentiated MO. Furthermore, …


Analysis Of Secreted Phosphoprotein-24 And Its Effects During Osteoblast Differentiation In A Mesenchymal Stem Cell Model, Vasquez Jochen Granja Jul 2009

Analysis Of Secreted Phosphoprotein-24 And Its Effects During Osteoblast Differentiation In A Mesenchymal Stem Cell Model, Vasquez Jochen Granja

Theses and Dissertations

Musculoskeletal diseases, in particular osteoporosis, are increasingly becoming more prevalent in the U.S. due to the ageing population (Figure1). It is estimated that one-sixth of 300 million people in U.S. suffer from bone disorders or loss. About 10 million of those people above age 50 suffer from osteoporosis. Patients that suffer from osteoporosis have high morbidity and mortality rates. For instance, patients have decreased bone mineral density (BMD), a measurement of bone density that reflects the strength of bone as represented by calcium content. A decrease in BMD typically leads to an increased risk of bone fractures. In particular, hip …


Synergistic Growth Inhibition And Enhancement Of Cell Death By Combination Of Melanoma Differentiation Associated Gene-7 (Mda-7/Il-24) And Cisplatin In Ovarian Cancer Cell Lines, Renyan Liu Jul 2009

Synergistic Growth Inhibition And Enhancement Of Cell Death By Combination Of Melanoma Differentiation Associated Gene-7 (Mda-7/Il-24) And Cisplatin In Ovarian Cancer Cell Lines, Renyan Liu

Theses and Dissertations

Ovarian cancer is the most lethal gynecological malignancy among women. The current first-line treatments for ovarian cancer are cisplatin, carboplatin and paclitaxel. However, resistance to these platinum-based drugs occurs in the large majority of initially responsive tumors, resulting in fully chemoresistant, fatal disease. Therefore, the resistance to cisplatin therapy has been a critical hurdle in the management of recurrent ovarian cancer. The mechanisms responsible for cisplatin resistance are not completely understood. In the search for new therapies to overcome/bypass cisplatin resistance, melanoma differentiation gene-7 (MDA-7) IL-24, which is a new cytokine, has anti-cancer efficacy by suppressing cell growth and inducing …


Intracellular Targets Of Sphingosine-1-Phosphate, Graham Michael Strub Jul 2009

Intracellular Targets Of Sphingosine-1-Phosphate, Graham Michael Strub

Theses and Dissertations

The bioactive lipid mediator sphingosine-1-phosphate (S1P) has emerged as a key regulator of a variety of important physiological functions, including cell growth, cell survival, cell motility, angiogenesis, lymphocyte trafficking, and mast cell function. S1P is formed by two different sphingosine kinases (SphKs) and binds to a family of 5 differentially expressed G-protein coupled receptors (S1PRs). The majority of research to date has focused on the activation of these receptors, but there is compelling evidence to suggest that S1P exerts intracellular functions independent of S1PRs. However no bona fide intracellular targets of S1P have been identified. In my dissertation, I have …


Sphingosine Kinase 1 Inhibitor, A Novel Inducer Of Autophagy, Daniel Meza Jul 2009

Sphingosine Kinase 1 Inhibitor, A Novel Inducer Of Autophagy, Daniel Meza

Theses and Dissertations

Autophagy is the process of “cell self-eating” which has been implicated both in cell survival and cell death. Sphingosine kinase 1 (SphK1) regulates the intracellular balance between ceramide and sphingosine, bioactive lipids associated with cell death, and sphingosine-1-phosphate (S1P), whose actions are associated with survival and proliferation. Previous studies have implicated upregulation of SphK1 in the induction of autophagy. In this study, SK1-I, a SphK1 specific competitive inhibitor, induced autophagy in a concentration and time dependent manner in HCT116 colorectal carcinoma cells. This autophagic response was observed to be more intense in wild type p53 expressing HCT116 cells than in …


Expression Of Chemokines And Vegfs In Hnscc, Crystal Cunningham May 2009

Expression Of Chemokines And Vegfs In Hnscc, Crystal Cunningham

Theses and Dissertations

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide. The 5-year survival rate when the cancer remains as a primary tumor is 81% but when it metastasizes to distant sites, defined as a metastatic cancer, it decreases dramatically to 26%. Approaches to prevent these cancers from undergoing these metastatic changes can greatly improve the survival and outcome of these cancer victims. This current study is examining the expression profiles of chemokines and VEGFs in HNSCC. By investigation the underlying pathways involved in the expressions of chemokines and VEGFS we hope to sort out the transcriptional …


The Small Molecule Bcl-2 Inhibitor Ha14-1 Potentiates The Lethality Of A Regimen Combining Mek1/2 And Chk1 Inhibitors In Multiple Myeloma Cells, Leena Youssefian May 2009

The Small Molecule Bcl-2 Inhibitor Ha14-1 Potentiates The Lethality Of A Regimen Combining Mek1/2 And Chk1 Inhibitors In Multiple Myeloma Cells, Leena Youssefian

Theses and Dissertations

Previously, we have found that the co-administration of MEK1/2 inhibitors and Chk1 inhibitors synergistically induce multiple myeloma cell apoptosis through upregulation of the BH3-only pro-apoptotic protein Bim. However, these apoptotic events were largely blocked by the characteristic over-expression of Bcl-2 of Bcl-xL in multiple myeloma cells. HA14-1, a small molecule Bcl-2 inhibitor, may therefore circumvent this resistance to apoptosis by blocking Bcl-2 and Bcl-xL anti-apoptotic protein actions. In our project, we hypothesize that the co-administration of HA14-1 with MEK/Chk1 inhibitors will enhance apoptosis in multiple myeloma (MM) cells. To test this hypothesis, we exposed MM cells U266 and RPMI8226, or …


Role Of The Porphyromonas Gingivalis Ecf Sigma Factor, Sigh, In Oxidative Stress Response, Sara Sarrafee Apr 2009

Role Of The Porphyromonas Gingivalis Ecf Sigma Factor, Sigh, In Oxidative Stress Response, Sara Sarrafee

Theses and Dissertations

Periodontal disease affects a majority of the US population. Porphyromonas gingivalis is the major etiological agent for development and progression of the disease. P. gingivalis is a hemin-dependent, obligate anaerobe that is found predominantly in periodontal pockets in infected patients. So for, little is known regarding the mechanisms which allow P. gingivalis to survive and sustain itself in the oral cavity. To better understand the adaptive mechanisms of the bacterium to the varying conditions in the oral cavity, regulatory mechanisms must be characterized. Sigma factors (σ) are responsible for initiating transcription by guiding RNA polymerase binding to specific DNA promoter …


The Second Generation Proteasome Inhibitor Carfilzomib Interacts Synergistically With Hdac Inhibitors In Diffuse Large B-Cell Lymphoma Cells Through Multiple Mechanisms And Circumvents Bortezomib Resistance, Dmitry Lembersky Apr 2009

The Second Generation Proteasome Inhibitor Carfilzomib Interacts Synergistically With Hdac Inhibitors In Diffuse Large B-Cell Lymphoma Cells Through Multiple Mechanisms And Circumvents Bortezomib Resistance, Dmitry Lembersky

Theses and Dissertations

Mechanisms underlying the interactions between the proteasome inhibitor carfilzomib and HDAC inhibitors were examined in both germinal center (GC) and activated B-cell (ABC) subtypes of human diffuse large B-cell lymphoma (DLBCL). Simultaneous exposure to minimally toxic concentrations of carfilzomib and HDAC inhibitor vorinostat resulted in the release of mitochondrial pro-apoptotic proteins SMAC and cytochrome c, pro-apoptotic caspase activation, and synergistic induction in apoptosis in both ABC and GC DLBCL subtypes. These events were associated with a marked increase in the stress kinase JNK, ROS generation, G2-M cell cycle arrest, as well as induction of DNA damage. Genetic knockdown of JNK …


The Role Of Brca1 In Dna Double-Strand Break Repair, Seth Dever Apr 2009

The Role Of Brca1 In Dna Double-Strand Break Repair, Seth Dever

Theses and Dissertations

Mutations in the breast cancer susceptibility 1 (BRCA1) gene are linked to breast as well as ovarian cancers. However, most cancer-causing mutations within the BRCA1 gene have been found in the N’ and C’ terminal regions of the BRCA1 protein, both believed to be important for DNA double-strand break (DSB) repair. The BRCA1 C’ terminal (BRCT) repeats have been implicated in phospho-serine protein binding whereas the N’ terminal RING domain interacts with the BARD1 protein to form a hetero-dimeric complex with E3 ubiquitin ligase activity. The BRCA1 BRCT domain binds CtIP, BACH1, and RAP80, all of which have been directly …


Scribble As A Possible Binding Partner For The Map Kinases Erk2 And Erk6, William Allen Apr 2009

Scribble As A Possible Binding Partner For The Map Kinases Erk2 And Erk6, William Allen

Theses and Dissertations

We worked on finding a new kinase regulator to develop basic data to be used for cancer prevention. Our work found a link between three previously unrelated proteins involved in cancer, ERK2 and ERK6 and Scribble. The MAP kinase cascade is involved in cell proliferation, which is highly deregulated in cancer. Through the screening of ERK6 associating molecules, we found the cell polarity, and cell cycle related molecule Scribble. Furthermore, we found that Scribble was a dual-specific kinase regulator. We clearly demonstrated that these ERKs interact with Scribble through the LRR and the PDZ domains of Scribble. We hypothesize that …


Novel Mechanisms Regulating Cytokine-Induced Gene Expression In Astrocytes And Glioblastoma Cells, Lauren Bryan Apr 2009

Novel Mechanisms Regulating Cytokine-Induced Gene Expression In Astrocytes And Glioblastoma Cells, Lauren Bryan

Theses and Dissertations

Chronic inflammation in the brain results in the development of several CNS diseases, including Alzheimer’s and Parkinson’s diseases, multiple sclerosis, and tumors. IL-1, a pro-inflammatory cytokine released by activated microglia and astrocytes, instigates the expression of factors promoting the progression of these CNS disorders, including cytokines, chemokines, and components of matrix remodeling systems, such as the plasminogen activator system. IL-1 also increases the mRNA expression and activity of SphK, the enzyme that phosphorylates Sph to form S1P, a bio-active sphingolipid. This thesis demonstrates that IL-1 and S1P enhance the mRNA and protein expression of PAI-1 and uPAR, two key components …


Molecular Mechanisms For Regulation Of Gene Expression By Lysophosphatidic Acid In Ovarian Carcinoma Cells, Regina Oyesanya Apr 2009

Molecular Mechanisms For Regulation Of Gene Expression By Lysophosphatidic Acid In Ovarian Carcinoma Cells, Regina Oyesanya

Theses and Dissertations

Lysophosphatidic acid (LPA) is a potent bioactive phospholipid mediator that functions through multiple G protein couple receptors (GPCRs). LPA is elevated in ascites of ovarian cancer patients and is involved in growth, survival and metastasis of ovarian cancer cells. Gene promoter analyses revealed that some LPA-target genes share similar sets of binding sites for prominent transcription factors posing the possibility of a general mechanism for activation of their expression by LPA. Detailed investigation of the mechanisms of regulation of cyclooxygenase 2 (Cox-2), a paradigm of LPA-regulated genes, showed that LPA robustly upregulated the expression of Cox-2 in ovarian cancer cells …


Role Of Rock And Pkc In Regulation Of Contraction Of Permeabilized Femoral Arterial Smooth Muscle, Brendan Browne Feb 2009

Role Of Rock And Pkc In Regulation Of Contraction Of Permeabilized Femoral Arterial Smooth Muscle, Brendan Browne

Theses and Dissertations

KCl is traditionally used as a stimulus to examine the role of increases in cytosolic Ca2+ on the regulation of smooth muscle contraction. KCl bypasses GPCR activation, thereby avoiding activation of additional cell signaling systems, such as phospholipase C and PKC that are inherent to Gaq and Ga12/13 stimulation. GPCR activation causes Ca2+ sensitization (greater force for a given increase in Ca2+) by a ROCK- and PKC-dependent inhibition of myosin light chain (MLC) phosphatase. Recent studies have demonstrated that KCl can also produce Ca2+ sensitization, implying that Ca2+ itself may induce Ca2+ sensitization. To test the hypothesis that Ca2+ can …


Molecular Mechanisms Involved In Oligodendrocyte Development, Rochelle Coelho Dec 2008

Molecular Mechanisms Involved In Oligodendrocyte Development, Rochelle Coelho

Theses and Dissertations

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by demyelination and loss of oligodendrocytes (OLGs), the CNS myelin-producing cells. Thus, understanding the mechanisms that control OLG development can provide valuable knowledge regarding remyelination therapies for MS. This disease is thought to result from an autoimmune attack towards myelin. FTY720, an immunomodulator under evaluation for MS treatment is a sphingosine-1-phosphate (S1P) analog. We found before that S1P plays a crucial role in the NT-3-mediated survival of OLGs, an observation that led us to investigate whether FTY720 could have any effect on these cells. Our studies …


Regulation Of Mdm2 Mediated Nfκb2 Pathway In Human Lung Cancer, Lathika Mohanraj Dec 2008

Regulation Of Mdm2 Mediated Nfκb2 Pathway In Human Lung Cancer, Lathika Mohanraj

Theses and Dissertations

Overexpression of oncoprotein MDM2 and mutations of tumor suppressor p53 are frequently observed in human cancers. The NFκB pathway is one of the deregulated pathways in oncogenesis. The overall goal of the project was to study the regulation of NFκB pathway by MDM2 in lung cancer. Our first effort was to determine the frequency of MDM2 overexpression in human lung tumor samples and to identify co-occurring abnormal gene expression by studying the levels of MDM2 and members of NFκB pathway with respect to p53 status. Higher than normal levels of MDM2 were found in approximately 30% of the cancer samples …


Crosstalk Between Mdm2 And Akt Signaling Pathway In Oncogenesis., Mahesh Ramamoorthy Dec 2008

Crosstalk Between Mdm2 And Akt Signaling Pathway In Oncogenesis., Mahesh Ramamoorthy

Theses and Dissertations

MDM2, the human homologue of the Mouse Double Minute 2 gene product, has been shown to be over-expressed in many cancers and to induce tumorigenesis. The role of MDM2 in oncogenesis was thought to be p53 dependent. However recent years have shown MDM2 to be a key player in a complex network of interactions that affect cell cycle, apoptosis, and tumorigenesis in a p53 independent manner. Here we report a novel p53 independent role for the multidimensional protein MDM2; its ability to induce phosphorylation of Akt at serine 473 residue. Transient and stable over-expression of MDM2 in cultured cell lines …


Ceramide Kinase And Ceramide-1-Phosphate, Dayanjan Wijesinghe Nov 2008

Ceramide Kinase And Ceramide-1-Phosphate, Dayanjan Wijesinghe

Theses and Dissertations

Ceramide-1-phosphate (C1P) is a bioactive lipid that has been implicated in many biological processes. Our laboratory has conclusively demonstrated its role in inflammation via activation of cPLA2α. The only known enzyme to date responsible for direct synthesis of C1P is ceramide kinase. Very little was known about this enzyme in terms of its enzyme kinetics and substrate specificity. As CERK is an enzyme that acts on membrane lipids, its kinetics cannot be studied using standard bulk dilutions methods. Thus we developed a surface dilution approach using Triton X 100 mixed micelles for studying the kinetics of CERK. We discovered that …


The Response Of Hn4 Cells To Porphyromonas Gingivalis Dna, Cheyanne Warren Jun 2008

The Response Of Hn4 Cells To Porphyromonas Gingivalis Dna, Cheyanne Warren

Theses and Dissertations

Periodontal disease is one of the most common human diseases. Bacteria trigger the onset and progression of the disease and among them Porphyromonas gingivalis has been demonstrated to be a major etiologic agent. Although the interaction of the bacterium with the host is of major importance for the understanding of the disease mechanisms, both the host as well as the pathogen components involved in the interaction remain poorly understood. One of the bacterial components capable of eliciting a host response is unmethylated CpG DNA motifs found in bacteria. Thus, the first aim was to determine the response of oral epithelial …


Biological Functions Of The Novel Lysophosphatidic Acid (Lpa) Receptor, Lpa4/P2y9/Gpr23, Peilun Lee Apr 2008

Biological Functions Of The Novel Lysophosphatidic Acid (Lpa) Receptor, Lpa4/P2y9/Gpr23, Peilun Lee

Theses and Dissertations

Lysophosphatidic acid (LPA), a naturally occurring phospholipid present in serum and malignant effusions, elicits diverse biological functions through binding and activating specific cell surface G-protein coupled receptors. In addition to the conventional LPA1/Edg2, LPA2/Edg4 and LPA3/Edg7 receptors of the endothelial differentiation gene (Edg) family, LPA4/p2y9/GPR23 of the purinergic receptor family and the related LPA5/GPR92 and LPA6/p2y5 have been identified as novel LPA receptors. These newly identified LPA receptors are structurally distant from the Edg LPA1-3 receptors and couple to Gq, G12/13 and probably Gs subunits. However, the roles of the LPA4-6 receptors in LPA signal transduction and physiology are poorly …


Inflammation-Associated Gene Regulation In Primary Astrocytes, Glial Tumors And Cellular Differentiation, Katarzyna Marta Wilczynska Jan 2008

Inflammation-Associated Gene Regulation In Primary Astrocytes, Glial Tumors And Cellular Differentiation, Katarzyna Marta Wilczynska

Theses and Dissertations

This dissertation elucidates several independent molecular mechanisms that function in astrocytes and glial tumor cells, and suggest that developmental and inflammatory signals may contribute to the development of brain tumors. First, we analyzed the mechanism of TIMP-1 activation in astrocytes and glioblastoma cells. TIMP-1 expression is activated by IL-1, which is the major neuroinflammatory cytokine, via simultaneous activation of IKK/NF-kB and MEK3/6/p38/ATF-2 pathways in primary human astrocytes. In contrast to astrocytes, TIMP-1 is expressed at lower levels in glioblastomas, and is not regulated by IL-1 due to either dysfunctional IKK/NF-kB or MEK3/6/p38/ATF-2 activation. Thus, we propose a novel mechanism of …


Regulation Of Platelet-Activating Factor Acetylhydrolase By Oxidized Phospholipids And Proinflammatory Cytokines, Muralikrishna Mukkamala Jan 2008

Regulation Of Platelet-Activating Factor Acetylhydrolase By Oxidized Phospholipids And Proinflammatory Cytokines, Muralikrishna Mukkamala

Theses and Dissertations

Platelet-Activating Factor Acetylhydrolase (PAFAH) is a monocyte-derived phospholipase A2 that catalyzes the hydrolysis of platelet-activating factor (PAF) and has been implicated in atherosclerosis. Although PAF and other proinflammatory stimuli are postulated to induce the enzyme, mechanisms controlling PAFAH expression are largely unknown at present. We have shown that PAFAH induction in monocytes is increased in response to oxidized phospholipids. The PAFAH 5' flanking region has at least 10 putative Stat elements, and IL-6 has been shown to be downstream from the prostaglandin receptor, EP2, which has been shown to bind oxidized phospholipids, prompting the hypothesis that Stat proteins might regulate …