Molecular Biology Commons^™

The Importance Of Protein Context In Spinocerebellar Ataxia Type 3, Sean Luis Johnson

Wayne State University Dissertations

Spinocerebellar Ataxia Type 3 (SCA3) is a member of the family of polyglutamine (polyQ) neurodegenerative disorders that includes Huntington's Disease and several other SCAs. SCA3, the most common dominant ataxia in the world, is caused by polyQ tract expansion in the protein, ataxin-3. How SCA3 occurs and how to treat it remain unresolved issues. The primary culprit of toxicity in all polyQ diseases is the glutamine repeat: its abnormal expansion leads to neuronal dysfunction and death. With that said, there is indisputable evidence that the way polyQ-dependent toxicity presents—areas impacted, cellular processes perturbed—is predicated in large part on regions outside …

Deconstructing Brown Adipocyte Neogenesis In Brown And White Adipose Tissue, Rayanne Burl

Wayne State University Dissertations

Global incidence of Type 2 Diabetes (T2D) has reached epidemic proportions, and increasing evidence indicates that dysfunctional adipose tissue is an important contributor to the pathogenesis of T2D. Expanding brown adipocyte (BA) populations within adipose tissues through adrenergic activation improves energy balance and insulin sensitivity. In order to exploit this remodeling of adipose tissue for therapeutic benefit, we need to understand the mechanisms by which adrenergic signaling expand populations of BAs in vivo. These studies utilized single-cell RNA-sequencing and transgenic mouse models, in combination with single-molecule fluorescence in situ hybridization (smFISH) and immunoistochemical analysis, to study BA neogenesis in vivo. …

Mnrr1: Understanding The Role Of A Novel Mitochondrial-Nuclear Regulator, Stephanie L. Gladyck

Wayne State University Dissertations

Mitochondria are complex organelles that generate most of the energy required to sustain life and function in metabolic and signaling pathways required to maintain cellular homeostasis. MNRR1 (mitochondrial nuclear retrograde regulator 1 or CHCHD2) is a small, bi-organellar twin CX9C protein that is emerging as an important regulator of mitochondrial function, apoptosis, and cellular stress by participating in mitochondrial-nuclear crosstalk. Our lab has previously shown that in the mitochondria, MNRR1 regulates complex IV (Cytochrome c oxidase or COX) and is able to finetune the oxidase function through phosphorylation status. We have also shown that during stress, mitochondrial MNRR1 levels deplete, …

Timing And Duration Of Folate Restriction Differentially Impacts Colon Carcinogenesis., Ali M. Fardous

Wayne State University Dissertations

Colorectal cancer (CRC) constitutes a major burden on the healthcare system as the second most commonly diagnosed cancer in the developed world. Dietary folate is considered an important modulator of colorectal cancer. Folate restriction has been implicated in increasing CRC incidence by disrupting nucleotide synthesis, Impacting DNA methylation and inducing genetic instability. Our research shows that the timing and duration of dietary folate restriction can differentially impact Colorectal cancer initiation. Acclimating mice to folate restriction for 8 weeks results in a reduced number of preneoplastic lesions compared to mice placed of folate restriction for 1 week prior to initiating the …

Termination-Independent Role Of Rat1 In Cotranscriptional Splicing In Budding Yeast, Zuzer Hakimuddin Dhoondia

Wayne State University Dissertations

Rat1 is a 5′→3′ exoribonuclease in budding yeast belonging to the XRN-family of nucleases. It is a highly conserved protein with homologs being present in fission yeast, flies, worms, mice and humans. Rat1 and its homolog in metazoan have been shown to function in multiple facets of RNA metabolism. In this study, we report a novel role of Rat1 in splicing of pre-mRNA in budding yeast. In the absence of the functional Rat1 in the nucleus, an increase in the level of unspliced transcripts was observed in yeast cells. Strand-specific TRO analysis revealed that the accumulation of unspliced transcripts upon …

Hormonal Regulation Of Glycine Decarboxylase And Its Metabolic Outcomes, Ruta Milind Jog

Wayne State University Dissertations

The amino acid glycine is involved in generation of multiple critical metabolites including glutathione, heme, and creatinine. Interestingly, in both humans and rodents, circulating glycine levels are significantly reduced in obesity, glucose intolerance, type II diabetes and non-alcoholic fatty liver disease. The glycine cleavage system is the predominant glycine degradation pathway in humans. The rate-limiting enzyme of glycine cleavage system is glycine decarboxylase (GLDC), and loss-of-function mutations of GLDC cause hyperglycinemia. Here, we show that GLDC gene expression is upregulated in livers of mouse models of diabetes and diet-induced obesity as well as in the fasted state in normal animals. …

Novel Insights Into The Critical Role Of Cardiolipin In Cellular Metabolism And Mitochondrial Physiology, Jiajia Ji

Wayne State University Dissertations

Cardiolipin (CL) is the signature phospholipid of mitochondria. CL and its remodeling exert critical roles in biological processes both inside and outside of mitochondria. CL abnormalities have been associated with various mitochondrial disorders and aging. Understanding the role of CL in mitochondrial physiology and cellular metabolism could provide valuable insights into cell biology and human health. Several metabolic alterations have been reported in CL-deficient cells, including accumulated lactate, decreased PDH activity, and decreased TCA cycle function. This dissertation connected these findings by showing abnormal NAD+ metabolism in various models lacking CL. Importantly, it shows that NAD+ supplementation improves mitochondrial function …

Germinal Center B Cell Expression Of Aire Regulates Antibody Diversification And Autoimmunity, Jordan Zheng Zhou

Wayne State University Dissertations

B cells are a unique subset of immune cells that, in response to antigen, diversify their antibody repertoire to generate progressively higher affinity antibodies of different isotypes through the processes of affinity maturation/somatic hypermutation (SHM) and class switch recombination (CSR). One of the major sites in which this diversification occurs is in T cell dependent microanatomical structures known as germinal centers (GC). Here, we find that GC B cells express the protein, autoimmune regulator (Aire) in a CD40 dependent manner. In these cells, Aire interacts with activation induced cytidine deaminase (AID), the protein responsible for initiating the processes of diversification …

The Role Of The Cell-Surface Protease Tmprss13 In Colorectal Cancer, Fausto Alexander Varela

Wayne State University Dissertations

Colorectal cancer (CRC) is one of the most common and deadly cancers in both men and women in the United States. Extracellular proteolysis is often dysregulated in cancer including (CRC), resulting in degradation of extracellular matrix, as well as cleavage, processing, or shedding of cell adhesion molecules, growth factors, and cytokines. Several members of the type II transmembrane serine protease (TTSP) family have been shown to play critical roles in cancer progression; however, many family members have not yet been characterized in malignancy. We identified TMPRSS13 transcript to be upregulated in CRC compared to normal colon. This increase was confirmed …

Defining The Effect Of Environmental Perturbation On The Male Germline, Molly Estill

Wayne State University Dissertations

Periconceptional environment, according to the Developmental Origins of Health and Disease (DOHaD) theory, influences offspring phenotype, primarily via epigenetic mechanisms. Although the paternal component in humans is poorly understood, both maternal and paternal peri-conceptional environment are now believed to contribute to this phenomenon. Manipulation of the early embryo for treating human infertility, is suspected of contributing to offspring abnormalities through epigenetic mechanisms. To directly address the effects of common assisted reproductive technology procedures on the offspring epigenome, the DNA methylation profiles of newborns conceived naturally, or through the use of intrauterine insemination (IUI), or in vitro fertilization (IVF) using Fresh …

Perturbation Of Energy Metabolism At The Center Of The Mechanism Of Action Of Valproate, Michael Ghassan Salsaa

Wayne State University Dissertations

Bipolar disorder (BD) is a common and debilitating psychiatric disorder. Valproic acid (VPA) is one of the major drugs used to treat BD patients. However, it is not universally effective and, in addition, causes severe side effects. Its mechanism of action is not known, which complicates efforts to develop more effective drugs. Studies have established that VPA perturbs metabolism, which is implicated in both the therapeutic mechanism of action of the drug as well as drug toxicity. However, the mechanism whereby VPA causes these perturbations is not understood. To address this knowledge gap, I investigated the acute and chronic effects …

Characterization Of Cytosolic Sulfotransferase Expression And Regulation In Human Liver And Intestine, Sarah Talal Dubaisi

Wayne State University Dissertations

SULTs are conjugation enzymes that can modify the activity of a myriad of foreign and endogenous molecules. SULT expression was detected in various human tissues, including liver, small intestine, and colon. There are 13 human SULT genes that are classified into 4 families, SULT1, SULT2, SULT4, and SULT6. In humans, SULT1 and SULT2 families include 11 genes that are further divided into 6 subfamilies. In addition to their role in xenobiotic detoxification and regulation of physiological processes, SULT enzymes were implicated in the bioactivation of procarcinogens. Previous studies detected the expression of most SULT1 and SULT2 enzymes during early development, …

The Balance Between Prostaglandin E2 Ep3 And Ep4 Receptors Determines Severity Of Cardiac Damage In Myocardial Infarction And An Angiotensin Ii-Induced Model Of Hypertension, Timothy Dean Bryson

Wayne State University Dissertations

According to the center for disease control about 610,000 people die every year in the United States from heart disease, of which, coronary heart disease is the most common form. One major risk factor for heart attack is hypertension, which affects nearly half of all Americans [472, 473]. PGE2 plays an important role in regulating cardiovascular function and mediating inflammation, both of which contribute to the development of hypertension and/or heart disease. Prostaglandin E2 can act as a vasodilator or vasoconstrictor depending on which of its receptor subtypes are activated.

In general, activation of the EP1 and EP3 receptors is …

Novel Insights Into The Use Of Ercc1 As A Biomarker For Response To Platinum-Based Chemotherapy In Lung Cancer, Joshua Ryan Heyza

Wayne State University Dissertations

ERCC1/XPF is a DNA endonuclease with variable expression in primary tumor specimens, and has been investigated as a predictive biomarker for efficacy of platinum-based chemotherapy in non-small cell lung cancers where up to 30-60% of tumors harbor low to undetectable ERCC1 expression. The failure of an international, randomized Phase III clinical trial utilizing ERCC1 expression to predict response to platinum-based chemotherapy suggests additional mechanisms underlying the basic biology of ERCC1 in the response to platinum-DNA damage remain unknown. In this work, we aimed to characterize a panel of ERCC1 knockout cell lines generated via CRISPR-Cas9 where we identified a synthetic …

Validating Functional Mechanisms For Non-Coding Genetic Variants Associated With Complex Traits, Cynthia Ann Kalita

Wayne State University Dissertations

Genome-wide association studies (GWAS) have identified a large number of genetic variants associated with disease as well as normal phenotypic variation for complex traits. However challenges remain in determining the functional relevance of human DNA sequence variants. Even after fine mapping, most variants are located in non-coding regions making it difficult to infer mechanisms linking individual genetic variants with the disease trait. In addition, we do not know under which environmental conditions the sequence variants have a functional impact, and whether they become one of many factors involved in complex phenotypes at the organismal level.

Chapter 1 describes computational methods …

Role Of Sirna Pathway In Epigenetic Modifications Of The Drosophila Melanogaster X Chromosome, Nikita Deshpande

Wayne State University Dissertations

Eukaryotic genomes are organized into large domains of coordinated regulation. The role of small RNAs in formation of these domains is largely unexplored. An extraordinary example of domain-wide regulation is X chromosome compensation in Drosophila melanogaster males. This process occurs by hypertranscription of genes on the single male X chromosome. Extensive research in this field has shown that the Male Specific Lethal (MSL) complex binds X-linked genes and modifies chromatin to increase expression. The components of this complex, and their actions on chromatin, are well studied. In contrast, the mechanism that results in exclusive recruitment to the X chromosome is …

Chchd10, A Novel Bi-Organellar Regulator Of Cellular Metabolism: Implications In Neurodegeneration, Neeraja Purandare

Wayne State University Dissertations

CHCHD10 (Coiled-coil Helix Coiled-coil Helix Domain containing protein 10) and MNRR1 (Mitochondrial Nuclear Retrograde Regulator 1, also known as CHCHD2), have been shown by us to be stress regulators of mitochondrial function that act both in the mitochondria and in the nucleus. Both are members of the twin CX9C family, but CHCHD10 in particular, has been found in mutant form to be linked to a myriad of neurodegenerative conditions. In mitochondria, both activate cytochrome c oxidase (COX) whereas in the nucleus, both act as transcription regulators of a subset of genes that contain a 13-bp sequence termed as the oxygen …

Effect Of Endoplasmic Reticulum Stress On Vascular Smooth Muscle Cells And Its Regulation Of Sm22Α, Neeraja Priyanka Annam

Wayne State University Dissertations

Background: The vascular smooth muscle cells(VSMC) possess the ability to differentiate into a synthetic phenotype in response to stress. This phenotypic modulation may be accompanied by inflammatory or osteogenic response in chronic stress. The synthetic state is characterized by low levels of contractile markers unlike the differentiated state.

Hypothesis: Endoplasmic reticulum (ER) stress causes phenotypic modulation in VSMCs leading to apoptosis. Many transcription factors induced by ER stress contribute to the downregulation of Sm22α. Perturbation in cytoskeletal dynamics exacerbates the ER stress response.

Methods: Ex-vivo culture was used to establish importance of Sm22 in ER stress. In vitro analysis was …

Role Of Alström Syndrome 1 (Alms1) In Nkcc2 Endocytosis, Thick Ascending Limb Function, Blood Pressure Regulation And Metabolic Function, Ankita Bachhawat Jaykumar

Wayne State University Dissertations

NaCl absorption by the Thick Ascending Limb (TAL) is mediated by the apical Na+/K+/2Cl- co-transporter, NKCC2. Increased NKCC2 activity and apical trafficking are associated to salt sensitive hypertension in rodents and humans. NKCC2 endocytosis is important for maintaining surface NKCC2 such that blocking NKCC2 endocytosis increased NKCC2 surface abundance and NKCC2-mediated NaCl reabsorption. Despite its importance, NKCC2 endocytosis has been poorly studied and a part of the reason may be attributed to the lack of availability of methods with good time resolution. Hence, we developed a method to image apical NKCC2 to monitor its endocytosis in real-time by Total Internal …

Analysis Of The Secondary Neurodegenerative Consequences Of Primary Oligodendrocyte Stress Through The Use Of The Novel Obiden Mouse Model, Daniel Zdzislaw Radecki

Wayne State University Dissertations

The work of this project was to develop, test and characterize a potential novel mouse model of the neurodegenerative disease Multiple Sclerosis (MS). Historically, MS has been identified as a primary autoimmune disease of the central nervous system (CNS). However, treatments based on this view have met with limited success, and in most cases, fail to prevent progression of MS from mild to moderate and severe forms. Original observations regarding axonal and neuronal pathology in the white and gray matter of the CNS were rediscovered in the 1990s. These observations indicated that even in the absence of the immune system, …

Identification Of Oxygen Optima For Mouse Trophoblast Stem Cells And Human Embryos And The Stress Responses Upon Departing Optima, Yu Yang

Wayne State University Dissertations

Low level of oxygen (O2) occurs physiologically during in vivo embryo development. As developing embryos moving from fallopian tube to uterus, oxygen level gradually decreases to ≤ 5% at the time of blastocyst implantation. Blastocysts are made of two major cell populations, trophoblast cells and inner cell mass, from which trophoblast stem cells (TSCs) and embryonic stem cells (ESCs) are derived respectively. TSCs serve as placental stem cells that later on proliferate and differentiate into placenta. Previous study has shown that 2% O2 is the optimal O2 level for mTSC in vitro growth and potency maintenance, which agrees with their …

Navigating Human Cytomegalovirus (Hcmv) Envelopment And Egress, William Longeway Close

Wayne State University Dissertations

Human cytomegalovirus (HCMV) is a ubiquitous viral pathogen. In individuals with fully functioning and mature immune systems, HCMV is associated with mild symptoms prior to establishing latency. In individuals with naïve or compromised immune systems, HCMV is capable of causing severe organ damage. HCMV is the leading infectious cause of congenital birth defects and a major non-genetic cause of hearing loss. Unfortunately, antiviral treatment options lack diversity due to limited knowledge of virion replication. If HCMV replication were better understood, new antiviral treatments could be developed.

In this work, we describe the development and implementation of new tools to study …

Studies Of Sumoylation In Regulating Mif Stability And Rangap1 Nucleo-Cytoplasmic Shuttling In Controlling Its Sumo Modification, Progga Sen

Wayne State University Dissertations

SUMOylation is an essential post-translational modification that regulates a variety of critical cellular pathways ranging from nuclear transport to protein stability. Accumulating lines of evidence have shown that a perturbation of the SUMOylation pathway is associated with human diseases, especially various types of cancer. Our recent proteomic studies revealed a drastic increase in levels of SUMO2/3 modification on the proinflammatory cytokine MIF in the metastatic breast cancer cell line compared to the non-metastatic control cell line. Interestingly, the increase in levels of both MIF and global SUMO-2/3 modification in the metastatic cells are positively correlated to that of unmodified MIF …

Clinicopathology And Molecular Determinants Underlying Benign Breast And Breast Cancer Lesions, Andreana Holowatyj Holowatyj

Wayne State University Dissertations

Despite converging incidence rates for breast cancers by race, disparities in mortality persist where black women suffer from poorer prognosis compared to white counterparts. To understand the clinical, demographic, and molecular characteristics underlying these disparities, we examined differences among patients with breast cancer to understand the role of human epidermal growth factor receptor 2 (HER2) status, age, and race/ethnicity among women diagnosed with hormone receptor-positive breast cancer, and disparities in surgical therapy among female patients with early stage young-onset breast cancer. Benign breast disease, another known risk factor for breast cancer, includes a histological spectrum of lesions, could contribute to …

Development Of A Novel Class Of Chemicals For Labeling Abasic Sites In Cellular Dna And Killing Cancer Cells, Shanqiao Wei

Wayne State University Dissertations

Abasic (AP) sites are the most common type of lesions in DNA. Numerous endogenous and exogenous agents and cellular processes can induce the formation of AP sites in DNA. If left unrepaired, the deleterious AP sites cause mutagenesis and cytotoxicity. Methoxyamine is known to react with AP sites and block base excision repair. Another alkoxyamine, aldehyde-reactive probe (ARP) tags AP sites with a biotin and has been widely used to quantify these sites. In this study, I have combined both these abilities into one alkoxyamine, AA3, which reacts toward AP sites with better reactivity than ARP at physiological pH. Additionally, …

Insights Into De Novo Fes-Cluster Biogenesis Via The Eukaryotic Fes-Cluster (Isc) Pathway In Vitro, Stephen Paul Dzul

Wayne State University Dissertations

Fe-S clusters are iron-containing cofactors utilized by numerous proteins within several biological pathways essential to life. In eukaryotes, the primary pathway for Fe-S cluster production is the iron-sulfur cluster (ISC) pathway. The eukaryotic ISC pathway, localized primarily within the mitochondria, has been best characterized within Saccharomyces cerevisiae. In yeast, de novo Fe-S cluster formation is accomplished through coordinated assembly of the substrates iron and sulfur on the primary scaffold assembly protein “Isu1”. The sulfur used for cluster assembly is provided by the cysteine desulfurase “Nfs1”, a protein that works in union with its accessory protein “Isd11”. Frataxin “Yfh1” helps direct …

Effective Drug Treatment Induces Drug Resistance Through Rapid Genome Alteration-Mediated Cancer Evolution, Steven Horne

Wayne State University Dissertations

The central paradox associated with current cancer therapeutic strategies is initially effective treatment, which eliminates a high tumor cell count, consistently results in successful drug resistance. Mathematical and evolutionary modeling have previously suggested that therapeutic intervention could provide selective pressure for the expansion of resistant variants. Drug-related stress has been associated with genome chaos, a common phenomenon in cancer characterized as rapid, stochastic genomic fragmentation and reorganization. Since cancer represents an evolutionary process, analysis within the context of genome-mediated cancer evolution can shed light on this key problem of therapeutics. We propose that genomic change is a general response to …

An Analysis Of The Interaction Between Sin3 And Methionine Metabolism In Drosophila, Mengying Liu

Wayne State University Dissertations

Chromatin modification and cellular metabolism are tightly connected. The mechanism for this cross-talk, however, remains incompletely understood. SIN3 controls histone acetylation through association with the histone deacetylase RPD3. In this study, my major goal is to explore the mechanism of how SIN3 regulates cellular metabolism.

Methionine metabolism generates the major methyl donor S-adenosylmethionine (SAM) for histone methylation. In collaboration with others, I report that reduced levels of some enzymes involved in methionine metabolism and histone demethylases lead to lethality, as well as wing development and cell proliferation defects in Drosophila melanogaster. Additionally, disruption of methionine metabolism can directly affect histone …

Investigating The Role Of Dna Polymerase Beta In The Aging Phenotype Of Down Syndrome, Aqila Ahmed Ahmed

Wayne State University Dissertations

Down syndrome (DS) is a chromosomal condition characterized by accelerated aging that has yet to be directly linked to a DNA repair defect. Reduced PolB and unrepaired damage from oxidative stress observed in DS, point toward defective base excision repair (BER). In this study, we report that low PolB transcript correlates with increased markers of senescence. The gene dosage effect of Trisomy 21 is likely the source for PolB downregulation. We show that the HSA21-localized miR-155 overexpression correlates with a decrease in Creb1 and PolB, thus establishing a putative regulatory pathway. Data from the DS mouse model, Ts65Dn, reveal low …

A Critical Role Of Cxcr2 Pdz Motif-Mediated Interactions In Endothelial Progenitor Cell Homing And Angiogenesis, Yuning Hou

Wayne State University Dissertations

Bone marrow-derived endothelial progenitor cells (EPCs) participate in postnatal vascularization in response to growth factors, cytokines, and chemokines. Chemokine receptor CXCR2 and its cognate ligands are reported to mediate EPC recruitment and angiogenesis. CXCR2 possesses a consensus PSD-95/DlgA/ZO-1 (PDZ) motif at its carboxyl terminus. The PDZ motif has been reported to regulate cellular signaling and functions. Here we investigated the potential role of the PDZ motif in CXCR2-mediated EPC motility and angiogenesis. We have found that introducing exogenous CXCR2 C-terminus significantly attenuated in vitro EPC migration and angiogenic activities in response to CXCR2 ligands, as well as in vivo EPC …