Cell Biology Commons^™

Evaluating Bioenergetics And Mitochondrial Dynamics In Patient Fibroblasts With Pathogenic Mitochondrial Dna Mutations Causing Leigh Syndrome, Ajibola Bakare

Graduate Theses and Dissertations

Leigh syndrome (LS) is a rare fatal mitochondrial disorder of infants caused by pathogenic mutations in the nuclear (nDNA) or mitochondrial DNA (mtDNA) leading to mitochondrial dysfunction. The extent to which pathogenic mtDNA variants regulate disease severity in LS is not well understood. The heterogeneous nature of this disorder, based in part by complex mitochondrial genetics, and the nuclear and mitochondrial cross-talk has made it particularly challenging to investigate and develop therapies for treating LS . While the prognosis is poor, several studies are underway to understand the pathophysiology of LS. This dissertation provides a comprehensive structural and functional analysis …

A Time-Course Characterization Of Muscle Function And Mitochondrial Markers During Colorectal Cancer-Induced Cachexia In Tumor-Bearing Male Mice, Ana Cabrera Ayuso

Graduate Theses and Dissertations

Cachexia is a multisystemic and multifactorial syndrome prevalent in cancer patients. It is clinically defined by involuntary loss of >5% weight in a six-month window, despite nutritional interventions. A negative energy balance characterizes cancer cachexia (CC), it is associated with weakness and fatigue in skeletal muscle. Impaired muscle function is associated with lower quality of life in cancer patients. Defects in mitochondrial function are strongly associated with muscle wasting. This study explored muscular contractile function and mitochondrial quality control (MQC) markers in soleus, gastrocnemius, and tibialis anterior (TA) muscles of C26-induced male tumor-bearing mice during a 25-day time course. It …

Mitochondrial Distribution Of Glycine Receptors In Motor Neuron Cell Lines, Katsiaryna Milashevich

Student Theses and Dissertations

Although non-essential, glycine plays an important role in major metabolic reactions and is most known for its anti-inflammatory effects. An accumulation of contemporary research has shown that glycine is able to stabilize membrane potential using glycine receptors at the cellular level and to protect mitochondrial function directly, whether it is from inflammation, heavy metal poisoning, or ischemia-induced neuroinflammation. In this research, the existence of a hypothetical mitochondrial glycine receptor is examined. Immunofluorescence imaging was used to examine the presence of the glycine receptor subunits alpha 1 and alpha 2 in both non- differentiated and differentiated neuroblastoma cell lines. The preliminary …

Review: The Bidirectional Relationship Between Mitochondrial Respiratory Chain Inhibition And Import Machinery Malfunction In Parkinson’S Disease, Grace Riggs, Deepa Dabir

Honors Thesis

Parkinson’s Disease (PD) is characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) portion of the ventral midbrain, the region of the brain largely responsible for motor control, executive cognitive function, and emotional limbic activity (Sonne 2020). SNpc dopaminergic neurons are more vulnerable than those in other regions due to their high energy demand arising from long, highly branched, unmyelinated axons (Pissadaki & Bolam 2013). They also have a higher basal rate of oxidative phosphorylation, which has been hypothesized to further increase vulnerability in cases of PD (Pacelli et al., 2015). One of the major …

Identifying New Markers And Mechanisms Of Mitochondrial Defect During Aging, Catherine Chang

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Mitochondrial dysfunction is a hallmark of aging and has been closely tied to age-related pathologies, such as cancer, cardiovascular diseases, neurodegenerative disorders, and metabolic syndromes. Though the consequences of mitochondrial defects are well documented, little is known about the molecular events that occur with age that transform healthy mitochondria into dysfunctional ones. Past studies have attempted to uncover the underlying proteomic changes in age, however, most of these results do not take into account population heterogeneity often associated with aging, thus highlighting the need for single-cell analysis. Technological barriers have impeded in-depth proteomic studies of aging mitochondria on a single …

Quantification Of Mitochondrial Zinc Homeostasis And Analysis Of Zinc And Polyamine-Mediated Axonal Trafficking, Dylan Hunt Fudge

Electronic Theses and Dissertations

The zinc ion is an important emerging signaling molecule for biological processes. In this work we engineered improved zinc sensors based on our previously developed fluorescent sensor GZnP1 to provide sensors with a higher fluorescent readout, faster kinetics, and a superior sensitivity to zinc. We utilized these zinc sensors and further developed the sensors to answer questions pertaining to biological zinc. We showed the labile zinc concentration in the mitochondrial matrix was less than 1 pM while the labile zinc concentration in the cytosol and mitochondrial IMS were comparable (~100 pM) across four different cell lines. Using these zinc sensors …

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 …

The Yeast Protein Mam33 Functions In The Assembly Of The Mitochondrial Ribosome, Gabrielle A Hillman, Michael F Henry

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Mitochondrial ribosomes are functionally specialized for the synthesis of several essential inner membrane proteins of the respiratory chain. Although remarkable progress has been made toward understanding the structure of mitoribosomes, the pathways and factors that facilitate their biogenesis remain largely unknown. The long unstructured domains of unassembled ribosomal proteins are highly prone to misfolding and often require dedicated chaperones to prevent aggregation. To date, chaperones that ensure safe delivery to the assembling ribosome have not been identified in the mitochondrion. In this study, a respiratory synthetic lethality screen revealed a role for an evolutionarily conserved mitochondrial matrix protein called Mam33 …

A Dedicated Chaperone Mediates The Safe Transfer Of Mitoribosomal Proteins To Their Site Of Assembly, Gabrielle Ashley Hillman

Graduate School of Biomedical Sciences Theses and Dissertations

Mitochondrial ribosomes are functionally specialized for the synthesis of several essential inner membrane proteins of the respiratory chain. While remarkable progress has recently been made towards understanding the structure of mitoribosomes, the unique pathways and factors that facilitate their biogenesis remain largely unknown. This dissertation defines the physiological role of an evolutionarily conserved yeast protein called Mam33 in mitochondrial ribosome assembly. The biomedical relevance of this finding stems from the fact that mutations or changes in its expression of the human ortholog p32 result in mitochondrial dysfunction. In human patients, bi-allelic mutations cause severe multisystemic defects in mitochondrial energy metabolism, …

Hormone Signaling, Gene Expression, And Mitochondrial Hormone Receptor Expression In Avian Muscle (Cells), Kentu Rushadd Lassiter

Graduate Theses and Dissertations

Mitochondria are vital to the proper growth and function of muscle cells since they’re responsible for the majority of ATP production used for cellular energy. Previous studies have investigated how differences in mitochondrial function affects feed efficiency (FE) in broilers phenotyped for High and Low FE. Low FE broilers have been shown to have increased levels of reactive oxygen species (ROS), thus contributing to higher levels of oxidative stress and damage seen in these birds. Global gene and protein expression studies conducted on breast muscle of the High FE and Low FE phenotypes have suggested that differences in mitochondrial function …

Deletion Of Mgr2p Affects The Gating Behavior Of The Tim23 Complex, Oygul Mirzalieva, Shinhye Jeon, Kevin Damri, Ruth Hartke, Layla Drwesh, Keren Demishtein-Zohary, Abdussalam Azem, Cory D. Dunn, Pablo M. Peixoto

Publications and Research

The TIM23 complex is a hub for translocation of preproteins into or across the mitochondrial inner membrane. This dual sorting mechanism is currently being investigated, and in yeast appears to be regulated by a recently discovered subunit, the Mgr2 protein. Deletion of Mgr2p has been found to delay protein translocation into the matrix and accumulation in the inner membrane. This result and other findings suggested that Mgr2p controls the lateral release of inner membrane proteins harboring a stop-transfer signal that follows an N-terminal amino acid signal. However, the mechanism of lateral release is unknown. Here, we used patch clamp electrophysiology …

Expression Of Alternative Oxidase In The Copepod T. Californicus When Exposed To Environmental Stressors, Carly Tward

Theses and Dissertations (Comprehensive)

In addition to the typical electron transport system in animal mitochondria responsible for oxidative phosphorylation, some species possess an alternative oxidase (AOX) pathway, which causes electrons to bypass proton pumping complexes. Although AOX appears to be energetically wasteful, studies have revealed its wide taxonomic distribution, and indicate it plays a role in environmental stress tolerance. AOX discovery in animals is recent, and further research into its expression, regulation, and physiological role has been impeded by the lack of an experimental model organism. DNA database searches using bioinformatics revealed an AOX sequence present in the arthropod Tigriopus californicus. Multiple sequence …

Pyronaridine Exerts Potent Cytotoxicity On Human Breast And Hematological Cancer Cells Through Induction Of Apoptosis, Paulina J. Villanueva, Alberto Martinez, Sarah T. Baca, Rebecca E. Dejesus, Manuel Larragoity, Lisett Contreras, Denisse A. Gutierrez, Armando Varela-Ramirez, Renato J. Aguilera

Publications and Research

The potent antimalarial drug pyronaridine (PND) was tested for its potential as an anticancer drug. After exposing cancerous (17) and non-cancerous (2) cells to PND for 72 hr, PND was found to exhibit consistent and potent cytotoxic activity at low micromolar (μM) concentrations that ranged from 1.6 μM to 9.4 μM. Moreover, PND exerted a significant selective cytotoxicity index (SCI) on five out of seven breast cancer cell lines tested, with favorable values of 2.5 to 4.4, as compared with the non-cancerous breast MCF-10A cell line. By using the same comparison, PND exhibited a significant SCI on three out of …

Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee

Graduate Theses and Dissertations

Oxidative metabolism is required to produce adequate energy to sustain human life. A primary example of deteriorating oxidative capacity is seen in the cardiac musculature during chronic heart failure. This suggests that by improving oxidative potential, chronic heart disease could be mitigated and one approach to accomplish this may be through targeting the mt-mRNA translation system. Purpose: This investigation’s purpose was to characterize disruptions in mt-mRNA translation machinery in multiple forms of cardiomyopathy and to determine if mitochondrial mRNA translation initiation factor (mtIF2) is necessary to maintain oxidative capacity in cardiomyocytes. Methods Using a combination of animal and cell culture …

Mechanism Of Transcription Anti-Termination In Human Mitochondria., Hauke S Hillen, Andrey V Parshin, Karen Agaronyan, Yaroslav I Morozov, James J Graber, Aleksandar Chernev, Kathrin Schwinghammer, Henning Urlaub, Michael Anikin, Patrick Cramer, Dmitry Temiakov

Rowan-Virtua School of Osteopathic Medicine Departmental Research

In human mitochondria, transcription termination events at a G-quadruplex region near the replication origin are thought to drive replication of mtDNA by generation of an RNA primer. This process is suppressed by a key regulator of mtDNA-the transcription factor TEFM. We determined the structure of an anti-termination complex in which TEFM is bound to transcribing mtRNAP. The structure reveals interactions of the dimeric pseudonuclease core of TEFM with mobile structural elements in mtRNAP and the nucleic acid components of the elongation complex (EC). Binding of TEFM to the DNA forms a downstream "sliding clamp," providing high processivity to the EC. …

The Prohibitin Protein Complex Promotes Mitochondrial Stabilization And Cell Survival In Hematologic Malignancies, Elisa Robles Escajeda

Open Access Theses & Dissertations

Lymphocyte proliferation and differentiation is coordinated with high precision in healthy humans and is vital to maintaining a normal immune system. Imbalance of these events can result in the development of autoimmune diseases, immunodeficiencies and hematopoietic malignancies. These pathologies, specifically leukemia and lymphoma have a high incidence of relapse and mortality due to limited treatment options. Therefore, there is a critical need to characterize the signal transduction pathways and understand molecular hallmarks that mediate T cell activation in order to develop new strategies for diagnosis and treatments of these diseases.

Prohibitins (PHB1 and PHB2) have been proposed to play important …

Autophagy Regulation After Diet And Exercise In Non-Alcoholic Fatty Liver Disease, Megan Elizabeth Rosa

Graduate Theses and Dissertations

Along with the rise in obesity, rates of non-alcoholic fatty liver disease (NAFLD) have also increased. NAFLD may begin with fat accumulation in the liver, but can progress to non-alcoholic steatohepatitis (NASH), fibrosis, and eventual cirrhosis. With no pharmacological treatment for NASH, lifestyle interventions appear vital to maintaining liver health. Previous work has shown aberrant mitochondrial content/quality and autophagy in models of NAFLD. Exercise is known to improve mitochondrial health and possibly autophagy, thus autophagy may be a key regulatory factor for treatment of obesity induced-NAFLD. PURPOSE: The purpose of the study was to examine how weight loss from diet …

Axonal Transport And Life Cycle Of Mitochondria In Parkinson's Disease Model, Hyun Sung

Open Access Dissertations

In neurons, normal distribution and selective removal of mitochondria are essential for preserving compartmentalized cellular function. Parkin, an E3 ubiquitin ligase associated with familial Parkinson’s disease, has been implicated in mitochondrial dynamics and removal. However, it is not clear how Parkin plays a role in mitochondrial turnover in vivo, and whether the mature neurons possess a compartmentalized Parkin-dependent mitochondrial life cycle. Using the live Drosophila nervous system, here, I investigate the involvement of Parkin in mitochondrial dynamics; organelle distribution, morphology and removal. Parkin deficient animals displayed less number of axonal mitochondria without disturbing organelle motility behaviors, morphology and metabolic state. …

Mir494 Reduces Renal Cancer Cell Survival Coinciding With Increased Lipid Droplets And Mitochondrial Changes, Punashi Dutta, Edward Haller, Arielle Sharp, Meera Nanjundan

Molecular Biosciences Faculty Publications

Background: miRNAs can regulate cellular survival in various cancer cell types. Recent evidence implicates the formation of lipid droplets as a hallmark event during apoptotic cell death response. It is presently unknown whether MIR494, located at 14q32 which is deleted in renal cancers, reduces cell survival in renal cancer cells and if this process is accompanied by changes in the number of lipid droplets.

Methods: 769-P renal carcinoma cells were utilized for this study. Control or MIR494 mimic was expressed in these cells following which cell viability (via crystal violet) and apoptotic cell numbers (via Annexin V/PI staining) were …

Dynamic Regulation Of Mitochondrial Stat3 And Its Association With Cypd, Jeremy A. Meier

Theses and Dissertations

In recent years, a number of nuclear transcription factors have been shown to be present in the mitochondria where they have distinct roles in regulating mitochondrial function. Signal Transducer and Activator of Transcription 3 (STAT3), classically activated by the JAK family of receptor associated tyrosine kinases to drive nuclear gene expression, is one such transcription factor with a unique mitochondrial role. There, it has been shown to support oxidative phosphorylation, regulate mitochondrial-encoded transcripts, and be key for the transformation and growth of a number of different cancers. Despite its well-characterized functional importance at the level of the mitochondria, the mechanism …

A Mitochondria-Anchored Isoform Of The Actin-Nucleating Spire Protein Regulates Mitochondrial Division, Uri Manor, Sadie Bartholomew, Gonen Golani, Eric Christenson, Michael Kozlov, Henry Higgs, James Spudich, Jennifer Lippincott-Schwartz

Dartmouth Scholarship

Mitochondrial division, essential for survival in mammals, is enhanced by an inter-organellar process involving ER tubules encircling and constricting mitochondria. The force for constriction is thought to involve actin polymerization by the ER-anchored isoform of the formin protein inverted formin 2 (INF2). Unknown is the mechanism triggering INF2-mediated actin polymerization at ER-mitochondria intersections. We show that a novel isoform of the formin-binding, actin-nucleating protein Spire, Spire1C, localizes to mitochondria and directly links mitochondria to the actin cytoskeleton and the ER. Spire1C binds INF2 and promotes actin assembly on mitochondrial surfaces. Disrupting either Spire1C actin- or formin-binding activities reduces mitochondrial constriction …

Impacts Of Micrornas On Skeletal Muscle Protein Synthesis And Mitochondrial Quality, David Lee

Graduate Theses and Dissertations

microRNA (miRNA) post-transcriptional modification is becoming a well-established mechanism for controlling mRNA translation. microRNAs -1, -133, and -206 are under the control of skeletal muscle promoters and affect muscle plasticity and metabolic health. A detailed review on the generation and processing of miRNAs with a view to skeletal muscle brings up intriguing connections in the transcriptional connections between multiple miRNAs. Additionally, exciting new research has defined a role of miRNAs in skeletal muscle mitochondria showing an additional, direct link to metabolic function. Multiple investigations in models of exercise, aging, hypertrophy, and injury have shown how these interventions can affect miRNA …

Characterization Of Iron Response In Gynecological Cell Lines, Kyle A. Bauckman

USF Tampa Graduate Theses and Dissertations

Ovarian carcinoma afflicts over 22,000 women each year with a 5 year survival rate of only 18% for stage IV patients [23]. Current treatment options are limited due to high rates of drug resistance and recurrence. Further, the identity of "precursor lesions" which give rise to various subclasses of epithelial ovarian cancer has been evasive. This is due to discovery of the cancer at already an advanced stage. Interestingly, endometriosis a benign but invasive gynecological disease has been described as a "precursor lesion" in the development of specific subtypes of ovarian cancer. Endometriotic cyst development involves the accumulation of "old …

Modulation Of Bax/Bak Dependent Apoptosis By Sirtuin 3 And Mitochondrial Permeability Transition By Sirtuin 4, Manish Verma

Graduate School of Biomedical Sciences Theses and Dissertations

Mitochondria are dynamic organelles that regulate a myriad of cellular functions, including energy production and metabolic regulation. Mitochondria are also a critical regulator of cell death signaling cascades modulating both apoptotic and necrotic cell death. However, what determines which cell death pathway is activated is still unclear. The mitochondrial/intrinsic pathway of apoptosis is dependent on the activation of pro-apoptotic proteins, Bax and Bak, which induce mitochondrial outer membrane permeabilization (MOMP). Once the integrity of outer mitochondrial membrane (OMM) is compromised, pro-apoptotic intermembrane space proteins like cytochrome c, Smac/Diablo, Omi/HtrA2 and AIF are released into the cytoplasm, which activates the post-mitochondrial …

Intrinsic Apoptotic Pathway: Effects Of Calcium On Murine Cytochrome C Release In Brain And Liver Mitochondria, Dane M. Edwards

Senior Honors Theses

A cell may use one of three main apoptotic pathways leading to programmed cell death: the extrinsic pathway, the perforin/granzyme pathway and the intrinsic pathway. The most pertinent to this discussion is the intrinsic pathway, which utilizes the mitochondria as an essential intermediary. Mitochondria’s primary function in relation to this pathway is the subsequent release of pro-apoptotic factors including cytochrome c, which activate a caspase cascade leading to the death of the cell. Cytochrome c is released partly due to an increase in cytosolic calcium levels. Two methods of the release of cytochrome c have been proposed. The first is …

Improvements To The Forensic Analysis Of Mitochondrial Dna Typing, Elizabeth Montano

Honors Scholar Theses

Sequence analysis of human mitochondrial DNA (mtDNA) is an effective and reliable tool for the genetic characterization of forensic samples. The nature of the mitochondrial genome (mtgenome), its high copy number and small size (~17kb) makes it more resistant to degradation and more stable than nuclear DNA. For this reason mitochondrial DNA is often the only feasible option for the forensic analysis of environmentally compromised samples. Currently the forensic analysis of the mtgenome is restricted to the hypervariable regions, also known as the Displacement loop (d-loop). Previous studies, confirmed in the Strausbaugh lab, have demonstrated an increased variability in the …

Treatment Of Aortic Heart Valve Conduit With Glutamine And Heat Shock As A Means To Deter The Constituent Cellular Population From Becoming Apoptotic, Alyce Marie Linthurst Jones

Theses and Dissertations in Biomedical Sciences

Cryopreserved allograft heart valves represent the best solution for a patient with a failing heart valve. However, the constituent cells become apoptotic and within months of transplant the heart valve becomes acellular and the recipient's cells do not repopulate the allograft (3, 51). A strategy to prevent this situation would be to minimize or prevent apoptosis from occurring by strategically altering steps during heart valve processing. Recently it has been demonstrated that: 1) Heat shock protein 70 is a negative modulator of the apoptotic cascade; 2) Cells in culture exposed to hypothermic conditions produce heat shock protein 70 upon rewarming; …

Heterogeneity In Mitochondrial Morphology And Membrane Potential Is Independent Of The Nuclear Division Cycle In Multinucleate Fungal Cells, John P. Gerstenberger, Patricia Occhipinti, Amy S. Gladfelter

Dartmouth Scholarship

In the multinucleate filamentous fungus Ashbya gossypii, nuclei divide asynchronously in a common cytoplasm. We hypothesize that the division cycle machinery has a limited zone of influence in the cytoplasm to promote nuclear autonomy. Mitochondria in cultured mammalian cells undergo cell cycle-specific changes in morphology and membrane potential and therefore can serve as a reporter of the cell cycle state of the cytoplasm. To evaluate if the cell cycle state of nuclei in A. gossypii can influ

Higher Il-6 And Il6:Igf Ratio In Patients With Barth Syndrome, Lori D. Wilson, Sadeeka Al-Majid, Cyril Rakovski, Christina D. Schwindt

Mathematics, Physics, and Computer Science Faculty Articles and Research

Background: Barth Syndrome (BTHS) is a serious X-linked genetic disorder associated with mutations in the tafazzin gene (TAZ, also called G4.5). The multi-system disorder is primarily characterized by the following pathologies: cardiac and skeletal myopathies, neutropenia, growth delay, and exercise intolerance. Although growth anomalies have been widely reported in BTHS, there is a paucity of research on the role of inflammation and the potential link to alterations in growth factors levels in BTHS patients.

Methods: Plasma from 36 subjects, 22 patients with Barth Syndrome (0.5 - 24 yrs) and 14 healthy control males (8 - 21 yrs) was …

The Effects Of Luteinizing Hormone And Adenosine 3',5'-Cyclic Monophosphate On Phospholipid Metabolism By Luteal Mitochondria, Jim John Sadighian

Chemistry & Biochemistry Theses & Dissertations

Luteinizing hormone (LH) increases intracellular concentrations of adenosine 3', 5 '-cyclic monophosphate and the phosphoinositides, phosphatidylinositol (PI), PI 4'-phosphate (PIP) and PI 4' .5 1 - bispbosphate (PIP₂). It is believed that cAMP and the phosphoinositides act concertedly to regulate mitochondrial conversion of cholesterol to pregnenolone. This study examined the effects of LH and N⁶ ,O² -dibutyryl cAMP (dbcAMP) on phospholipids metabolism by luteal mitochondria and the influence of dbcAMP and the phosphoinosi tides on mitochondrial steroid production. Mitochondria were isolated from unincubated and incubated luteal tissue by differential centrifugation. Phospholipids were extracted from the mitochondria …