Medicine and Health Sciences Commons^™

Gpr84-Mediated Signal Transduction Affects Metabolic Function By Promoting Brown Adipocyte Activity, Xue-Nan Sun, Yu A An, Vivian A Paschoal, Camila O De Souza, May-Yun Wang, Lavanya Vishvanath, Lorena Ma Bueno, Ayanna S Cobb, Joseph A Nieto Carrion, Madison E Ibe, Chao Li, Harrison A Kidd, Shiuhwei Chen, Wenhong Li, Rana K Gupta, Da Young Oh

Student and Faculty Publications

The G protein-coupled receptor 84 (GPR84), a medium-chain fatty acid receptor, has garnered attention because of its potential involvement in a range of metabolic conditions. However, the precise mechanisms underlying this effect remain elusive. Our study has shed light on the pivotal role of GPR84, revealing its robust expression and functional significance within brown adipose tissue (BAT). Mice lacking GPR84 exhibited increased lipid accumulation in BAT, rendering them more susceptible to cold exposure and displaying reduced BAT activity compared with their WT counterparts. Our in vitro experiments with primary brown adipocytes from GPR84-KO mice revealed diminished expression of thermogenic genes …

The Adaptor Protein P66shc Governs Central Nervous System Cell Metabolism And Resistance To Aβ Toxicity, Asad Lone

Electronic Thesis and Dissertation Repository

Alzheimer’s disease (AD), a progressive and irreversible neurodegenerative disorder, and is the leading cause of dementia worldwide. It has been posited that AD is caused by the gradual deposition of toxic amyloid-b (Ab) plaques in the brain- that cause oxidative stress and eventually leads to neuronal death and synaptic loss. However, multiple therapies that either interfere with the production, or enhance the removal of Ab from the brain, have ultimately failed to slow or prevent AD. With the ever-increasing burden of AD worldwide, there exists an urgent need for novel therapeutic targets. The adult human brain is an energy demanding …

Diaph1-Mfn2 Interaction Regulates Mitochondria-Sr/Er Contact And Modulates Ischemic/Hypoxic Stress, Gautham Yepuri, Lisa M Ramirez, Gregory G Theophall, Sergei V Reverdatto, Nosirudeen Quadri, Syed Nurul Hasan, Lei Bu, Devi Thiagarajan, Robin Wilson, Raquel López Díez, Paul F Gugger, Kaamashri Mangar, Navneet Narula, Stuart D Katz, Boyan Zhou, Huilin Li, Aleksandr B Stotland, Roberta A Gottlieb, Ann Marie Schmidt, Alexander Shekhtman, Ravichandran Ramasamy

Student and Faculty Publications

Inter-organelle contact and communication between mitochondria and sarco/endoplasmic reticulum (SR/ER) maintain cellular homeostasis and are profoundly disturbed during tissue ischemia. We tested the hypothesis that the formin Diaphanous-1 (DIAPH1), which regulates actin dynamics, signal transduction and metabolic functions, contributes to these processes. We demonstrate that DIAPH1 interacts directly with Mitofusin-2 (MFN2) to shorten mitochondria-SR/ER distance, thereby enhancing mitochondria-ER contact in cells including cardiomyocytes, endothelial cells and macrophages. Solution structure studies affirm the interaction between the Diaphanous Inhibitory Domain and the cytosolic GTPase domain of MFN2. In male rodent and human cardiomyocytes, DIAPH1-MFN2 interaction regulates mitochondrial turnover, mitophagy, and oxidative stress. …

A Naturally Derived Watercress Flower-Based Phenethyl Isothiocyanate-Enriched Extract Induces The Activation Of Intrinsic Apoptosis Via Subcellular Ultrastructural And Ca2+ Efflux Alterations In An In Vitro Model Of Human Malignant Melanoma, Sotiris Kyriakou, Louiza Potamiti, Nikoletta Demosthenous, Tom Amery, Kyle Stewart, Paul G. Winyard, Rodrigo Franco, Aglaia Pappa, Mihalis I. Panayiotidis

School of Veterinary and Biomedical Sciences: Faculty Publications

The aim of the current study was to (i) extract isolated fractions of watercress flowers enriched in polyphenols, phenethyl isothiocyanate and glucosinolates and (ii) characterize the anticancer mode of action of non-lethal, sub-lethal and lethal concentrations of the most potent extract fraction in primary (A375) and metastatic (COLO-679) melanoma cells as well as non-tumorigenic immortalized keratinocyte (HaCaT) cells. Cytotoxicity was assessed via the Alamar Blue assay, whereas ultrastructural alterations in mitochondria and the endoplasmic reticulum were determined via transmission electron microscopy. Mitochondrial membrane depolarization was determined using Mito-MP dye, whereas apoptosis was evaluated through the activation of caspases-3, -8 and …

Enhanced Presynaptic Mitochondrial Energy Production Is Required For Memory Formation, Erica L Underwood, John B Redell, Kimberly N Hood, Mark E Maynard, Michael Hylin, M Neal Waxham, Jing Zhao, Anthony N Moore, Pramod K Dash

Student and Faculty Publications

Some of the prominent features of long-term memory formation include protein synthesis, gene expression, enhanced neurotransmitter release, increased excitability, and formation of new synapses. As these processes are critically dependent on mitochondrial function, we hypothesized that increased mitochondrial respiration and dynamics would play a prominent role in memory formation. To address this possibility, we measured mitochondrial oxygen consumption (OCR) in hippocampal tissue punches from trained and untrained animals. Our results show that context fear training significantly increased basal, ATP synthesis-linked, and maximal OCR in the Shaffer collateral-CA1 synaptic region, but not in the CA1 cell body layer. These changes were …

Antimicrobial Mitochondrial Reactive Oxygen Species Induction By Lung Epithelial Immunometabolic Modulation, Yongxing Wang, Vikram V Kulkarni, Jezreel Pantaleón García, Miguel M Leiva-Juárez, David L Goldblatt, Fahad Gulraiz, Lisandra Vila Ellis, Jichao Chen, Michael K Longmire, Sri Ramya Donepudi, Philip L Lorenzi, Hao Wang, Lee-Jun Wong, Michael J Tuvim, Scott E Evans

Student and Faculty Publications

Pneumonia is a worldwide threat, making discovery of novel means to combat lower respiratory tract infection an urgent need. Manipulating the lungs' intrinsic host defenses by therapeutic delivery of certain pathogen-associated molecular patterns protects mice against pneumonia in a reactive oxygen species (ROS)-dependent manner. Here we show that antimicrobial ROS are induced from lung epithelial cells by interactions of CpG oligodeoxynucleotides (ODN) with mitochondrial voltage-dependent anion channel 1 (VDAC1). The ODN-VDAC1 interaction alters cellular ATP/ADP/AMP localization, increases delivery of electrons to the electron transport chain (ETC), increases mitochondrial membrane potential (ΔΨm), differentially modulates ETC complex activities and consequently results in …

Activation Of Cell-Free Mtdna-Tlr9 Signaling Mediates Chronic Stress-Induced Social Behavior Deficits, Ashutosh Tripathi, Alona Bartosh, Carl Whitehead, Anilkumar Pillai

Student and Faculty Publications

Inflammation and social behavior deficits are associated with a number of neuropsychiatric disorders. Chronic stress, a major risk factor for depression and other mental health conditions is known to increase inflammatory responses and social behavior impairments. Disturbances in mitochondria function have been found in chronic stress conditions, however the mechanisms that link mitochondrial dysfunction to stress-induced social behavior deficits are not well understood. In this study, we found that chronic restraint stress (RS) induces significant increases in serum cell-free mitochondrial DNA (cf-mtDNA) levels in mice, and systemic Deoxyribonuclease I (DNase I) treatment attenuated RS-induced social behavioral deficits. Our findings revealed …

Pathobiology Of Myocardial Ischemia And Reperfusion Injury: Models, Modes, Molecular Mechanisms, Modulation, And Clinical Applications, L Maximilian Buja

Student and Faculty Publications

This review presents an integrated approach to the analysis of myocardial ischemia and reperfusion injury and the modulating influence of myocardial conditioning during the evolution of acute myocardial infarction (AMI) and other clinical settings. Experimental studies have involved a spectrum of in vitro, ex vivo, and in vivo models, and guidelines have been developed for the conduct of rigorous preclinical studies and for the identification of various forms of cell injury and death in evolving AMI. AMI in vivo is dominated by oncosis (cell injury with swelling) leading to necroptosis and final necrosis of ischemic cardiomyocytes (CMCs), without or with …

Gata6-As1 Regulates Intestinal Epithelial Mitochondrial Functions, And Its Reduced Expression Is Linked To Intestinal Inflammation And Less Favourable Disease Course In Ulcerative Colitis, Katya E Sosnovski, Tzipi Braun, Amnon Amir, Danielle Moshel, Marina Benshoshan, Kelli L Vandussen, Nina Levhar, Haya Abbas-Egbariya, Katia Beider, Rakefet Ben-Yishay, Syed Asad Ali, Sean R Moore, Subra Kugathasan, Ifat Abramovich, Efrat Glick Saar, Batya Weiss, Iris Barshack, Eyal Gottlieb, Tamar Geiger, Shomron Ben-Horin, Igor Ulitsky, Jeffrey S Hyams, Lee A Denson, Yael Haberman

Student and Faculty Publications

BACKGROUND AND AIMS: Widespread dysregulation of long non-coding RNAs [lncRNAs] including a reduction in GATA6-AS1 was noted in inflammatory bowel disease [IBD]. We previously reported a prominent inhibition of epithelial mitochondrial functions in ulcerative colitis [UC]. However, the connection between reduction of GATA6-AS1 expression and attenuated epithelial mitochondrial functions was not defined.

METHODS: Mucosal transcriptomics was used to conform GATA6-AS1 reduction in several treatment-naïve independent human cohorts [n=673]. RNA pull-down followed by mass spectrometry was used to determine the GATA6-AS1 interactome. Metabolomics and mitochondrial respiration following GATA6-AS1 silencing in Caco-2 cells were used to elaborate on GATA6-AS1 functions.

RESULTS: GATA6-AS1 …

Aryl Hydrocarbon Receptor Maintains Hepatic Mitochondrial Homeostasis In Mice, Mi Jeong Heo, Ji Ho Suh, Sung Ho Lee, Kyle L Poulsen, Yu A An, Bhagavatula Moorthy, Sean M Hartig, David D Moore, Kang Ho Kim

Student and Faculty Publications

OBJECTIVE: Mitophagy removes damaged mitochondria to maintain cellular homeostasis. Aryl hydrocarbon receptor (AhR) expression in the liver plays a crucial role in supporting normal liver functions, but its impact on mitochondrial function is unclear. Here, we identified a new role of AhR in the regulation of mitophagy to control hepatic energy homeostasis.

METHODS: In this study, we utilized primary hepatocytes from AhR knockout (KO) mice and AhR knockdown AML12 hepatocytes. An endogenous AhR ligand, kynurenine (Kyn), was used to activate AhR in AML12 hepatocytes. Mitochondrial function and mitophagy process were comprehensively assessed by MitoSOX and mt-Keima fluorescence imaging, Seahorse XF-based …

Mitochondrial Dysfunction: At The Nexus Between Alcohol-Associated Immunometabolic Dysregulation And Tissue Injury, Robert W. Siggins, Patrick M. Mcternan, Liz Simon, Flavia M. Souza-Smith, Patricia E. Molina

School of Medicine Faculty Publications

Alcohol misuse, directly or indirectly as a result of its metabolism, negatively impacts most tissues, including four with critical roles in energy metabolism regulation: the liver, pancreas, adipose, and skeletal muscle. Mitochondria have long been studied for their biosynthetic roles, such as ATP synthesis and initiation of apoptosis. However, current research has provided evidence that mitochondria participate in myriad cellular processes, including immune activation, nutrient sensing in pancreatic β-cells, and skeletal muscle stem and progenitor cell differentiation. The literature indicates that alcohol impairs mitochondrial respiratory capacity, promoting reactive oxygen species (ROS) generation and disrupting mitochondrial dynamics, leading to dysfunctional mitochondria …

Li-Fraumeni Syndrome-Associated Dimer-Forming Mutant P53 Promotes Transactivation-Independent Mitochondrial Cell Death, Joshua H Choe, Tatsuya Kawase, An Xu, Asja Guzman, Aleksandar Z Obradovic, Ana Maria Low-Calle, Bita Alaghebandan, Ananya Raghavan, Kaitlin Long, Paul M Hwang, Joshua D Schiffman, Yan Zhu, Ruiying Zhao, Dung-Fang Lee, Chen Katz, Carol Prives

Student and Faculty Publications

UNLABELLED: Cancer-relevant mutations in the oligomerization domain (OD) of the p53 tumor suppressor protein, unlike those in the DNA binding domain, have not been well elucidated. Here, we characterized the germline OD mutant p53(A347D), which occurs in cancer-prone Li-Fraumeni syndrome (LFS) patients. Unlike wild-type p53, mutant p53(A347D) cannot form tetramers and exists as a hyperstable dimeric protein. Further, p53(A347D) cannot bind or transactivate the majority of canonical p53 target genes. Isogenic cell lines harboring either p53(A347D) or no p53 yield comparable tumorigenic properties, yet p53(A347D) displays remarkable neomorphic activities. Cells bearing p53(A347D) possess a distinct transcriptional profile and undergo metabolic …

Sexual Dimorphism In Bidirectional Sr-Mitochondria Crosstalk In Ventricular Cardiomyocytes, Richard T Clements, Radmila Terentyeva, Shanna Hamilton, Paul M L Janssen, Karim Roder, Benjamin Y Martin, Fruzsina Perger, Timothy G Schneider, Zuzana Nichtova, Anindhya S Das, Roland Veress, Beth S Lee, Do-Gyoon Kim, Gideon Koren, Matthew S Stratton, György Csordás, Federica Accornero, Andriy E Belevych, Sandor Gyorke, Dmitry Terentyev

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Calcium transfer into the mitochondrial matrix during sarcoplasmic reticulum (SR) Ca²⁺ release is essential to boost energy production in ventricular cardiomyocytes (VCMs) and match increased metabolic demand. Mitochondria from female hearts exhibit lower mito-[Ca²⁺] and produce less reactive oxygen species (ROS) compared to males, without change in respiration capacity. We hypothesized that in female VCMs, more efficient electron transport chain (ETC) organization into supercomplexes offsets the deficit in mito-Ca²⁺ accumulation, thereby reducing ROS production and stress-induced intracellular Ca²⁺ mishandling. Experiments using mitochondria-targeted biosensors confirmed lower mito-ROS and mito-[Ca²⁺] in female rat VCMs challenged …

Micu1 Occludes The Mitochondrial Calcium Uniporter In Divalent-Free Conditions, Macarena Rodríguez-Prados, Elena Berezhnaya, Maria Teresa Castromonte, Sergio L. Menezes-Filho, Melanie Paillard, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitochondrial Ca2+ uptake is mediated by the mitochondrial uniporter complex (mtCU) that includes a tetramer of the pore-forming subunit, MCU, a scaffold protein, EMRE, and the EF-hand regulatory subunit, MICU1 either homodimerized or heterodimerized with MICU2/3. MICU1 has been proposed to regulate Ca2+ uptake via the mtCU by physically occluding the pore and preventing Ca2+ flux at resting cytoplasmic [Ca2+] (free calcium concentration) and to increase Ca2+ flux at high [Ca2+] due to cooperative activation of MICUs EF-hands. However, mtCU and MICU1 functioning when its EF-hands are unoccupied by Ca2+ is poorly studied due to technical limitations. To overcome this …

Ether Phospholipids Are Required For Mitochondrial Reactive Oxygen Species Homeostasis, Ziheng Chen, I-Lin Ho, Melinda Soeung, Er-Yen Yen, Jintan Liu, Liang Yan, Johnathon L Rose, Sanjana Srinivasan, Shan Jiang, Q Edward Chang, Ningping Feng, Jason P Gay, Qi Wang, Jing Wang, Philip L Lorenzi, Lucas J Veillon, Bo Wei, John N Weinstein, Angela K Deem, Sisi Gao, Giannicola Genovese, Andrea Viale, Wantong Yao, Costas A Lyssiotis, Joseph R Marszalek, Giulio F Draetta, Haoqiang Ying

Student and Faculty Publications

Mitochondria are hubs where bioenergetics, redox homeostasis, and anabolic metabolism pathways integrate through a tightly coordinated flux of metabolites. The contributions of mitochondrial metabolism to tumor growth and therapy resistance are evident, but drugs targeting mitochondrial metabolism have repeatedly failed in the clinic. Our study in pancreatic ductal adenocarcinoma (PDAC) finds that cellular and mitochondrial lipid composition influence cancer cell sensitivity to pharmacological inhibition of electron transport chain complex I. Profiling of patient-derived PDAC models revealed that monounsaturated fatty acids (MUFAs) and MUFA-linked ether phospholipids play a critical role in maintaining ROS homeostasis. We show that ether phospholipids support mitochondrial …

Structural Basis Of Impaired Disaggregase Function In The Oxidation-Sensitive Skd3 Mutant Causing 3-Methylglutaconic Aciduria, Sukyeong Lee, Sang Bum Lee, Nuri Sung, Wendy W Xu, Changsoo Chang, Hyun-Eui Kim, Andre Catic, Francis T F Tsai

Student and Faculty Publications

Mitochondria are critical to cellular and organismal health. To prevent damage, mitochondria have evolved protein quality control machines to survey and maintain the mitochondrial proteome. SKD3, also known as CLPB, is a ring-forming, ATP-fueled protein disaggregase essential for preserving mitochondrial integrity and structure. SKD3 deficiency causes 3-methylglutaconic aciduria type VII (MGCA7) and early death in infants, while mutations in the ATPase domain impair protein disaggregation with the observed loss-of-function correlating with disease severity. How mutations in the non-catalytic N-domain cause disease is unknown. Here, we show that the disease-associated N-domain mutation, Y272C, forms an intramolecular disulfide bond with Cys267 and …

Opa1 Disease-Causing Mutants Have Domain-Specific Effects On Mitochondrial Ultrastructure And Fusion, Benjamín Cartes-Saavedra, Daniel Lagos, Josefa Macuada, Duxan Arancibia, Florence Burté, Marcela K. Sjöberg-Herrera, María Estela Andrés, Rita Horvath, Patrick Yu-Wai-Man, György Hajnóczky, Verónica Eisner

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Inner mitochondrial membrane fusion and cristae shape depend on optic atrophy protein 1, OPA1. Mutations in OPA1 lead to autosomal dominant optic atrophy (ADOA), an important cause of inherited blindness. The Guanosin Triphosphatase (GTPase) and GTPase effector domains (GEDs) of OPA1 are essential for mitochondrial fusion; yet, their specific roles remain elusive. Intriguingly, patients carrying OPA1 GTPase mutations have a higher risk of developing more severe multisystemic symptoms in addition to optic atrophy, suggesting pathogenic contributions for the GTPase and GED domains, respectively. We studied OPA1 GTPase and GED mutations to understand their domain-specific contribution to protein function by analyzing …

Acute Acat1/Soat1 Blockade Increases Mam Cholesterol And Strengthens Er-Mitochondria Connectivity., Taylor C Harned, Radu V Stan, Ze Cao, Rajarshi Chakrabarti, Henry N Higgs, Catherine C Y Chang, Ta Yuan Chang

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Cholesterol is a key component of all mammalian cell membranes. Disruptions in cholesterol metabolism have been observed in the context of various diseases, including neurodegenerative disorders such as Alzheimer's disease (AD). The genetic and pharmacological blockade of acyl-CoA:cholesterol acyltransferase 1/sterol O-acyltransferase 1 (ACAT1/SOAT1), a cholesterol storage enzyme found on the endoplasmic reticulum (ER) and enriched at the mitochondria-associated ER membrane (MAM), has been shown to reduce amyloid pathology and rescue cognitive deficits in mouse models of AD. Additionally, blocking ACAT1/SOAT1 activity stimulates autophagy and lysosomal biogenesis; however, the exact molecular connection between the ACAT1/SOAT1 blockade and these observed benefits remain …

Conditioned Place Avoidance Is Associated With A Distinct Hippocampal Phenotype, Partly Preserved Pattern Separation, And Reduced Reactive Oxygen Species Production After Stress, D. Parker Kelley, Lucas Albrechet-Souza, Shealan Cruise, Rajani Maiya, Aspasia Destouni, Siva S.V.P. Sakamuri, Alexander Duplooy, Meghan Hibicke, Charles Nichols, Prasad V.G. Katakam, Nicholas W. Gilpin, Joseph Francis

School of Medicine Faculty Publications

Stress is associated with contextual memory deficits, which may mediate avoidance of trauma-associated contexts in posttraumatic stress disorder. These deficits may emerge from impaired pattern separation, the independent representation of similar experiences by the dentate gyrus-Cornu Ammonis 3 (DG-CA3) circuit of the dorsal hippocampus, which allows for appropriate behavioral responses to specific environmental stimuli. Neurogenesis in the DG is controlled by mitochondrial reactive oxygen species (ROS) production, and may contribute to pattern separation. In Experiment 1, we performed RNA sequencing of the dorsal hippocampus 16 days after stress in rats that either develop conditioned place avoidance to a predator urine-associated …

Chronic Restraint Stress Impairs Voluntary Wheel Running But Has No Effect On Food-Motivated Behavior In Mice, Kiersten Scott, Thien Trong Phan, Nabila Boukelmoune, Cobi J Heijnen, Robert Dantzer

Student and Faculty Publications

Chronic restraint stress is known to cause significant alterations of mitochondrial biology. However, its effects on effort-based behavior and the sensitivity of these effects to treatments that restore mitochondrial function have not been assessed. Based on the hypothesis that the behavioral consequences of this stressor should be more severe for an energy demanding activity than for an energy procuring activity, we compared the effects of chronic restraint stress on the performance of male mice trained to use a running wheel or to nose poke for a food reward in an operant conditioning cage. In accordance with our hypothesis, we observed …

Artificial Intelligence-Driven Meta-Analysis Of Brain Gene Expression Identifies Novel Gene Candidates And A Role For Mitochondria In Alzheimer’S Disease, Caitlin A Finney, Fabien Delerue, Wendy A Gold, David A Brown, Artur Shvetcov

Student and Faculty Publications

Alzheimer's disease (AD) is the most common form of dementia. There is no treatment and AD models have focused on a small subset of genes identified in familial AD. Microarray studies have identified thousands of dysregulated genes in the brains of patients with AD yet identifying the best gene candidates to both model and treat AD remains a challenge. We performed a meta-analysis of microarray data from the frontal cortex (n = 697) and cerebellum (n = 230) of AD patients and healthy controls. A two-stage artificial intelligence approach, with both unsupervised and supervised machine learning, combined with a functional …

High Energy Blue Light Induces Oxidative Stress And Retinal Cell Apoptosis, Jessica Malinsky

Capstone Showcase

Blue light (BL) is a high energy, short wavelength spanning 400 to 500 nm. Found in technological and environmental forms, BL has been shown to induce photochemical damage of the retina by reactive oxygen species (ROS) production. Excess ROS leads to oxidative stress, which disrupts retinal mitochondrial structure and function. As mitochondria amply occupy photoreceptors, they also contribute to oxidative stress due to their selectively significant absorption of BL at 400 to 500 nm. ROS generation that induces oxidative stress subsequently promotes retinal mitochondrial apoptosis. BL filtering and preventative mechanisms have been suggested to improve or repair BL-induced retinal damage, …

Mitochondria As Causes Of And Therapeutic Targets In Chronic Post-Sepsis Skeletal Muscle Weakness, Meagan Scott Kingren

Theses and Dissertations--Pharmacology and Nutritional Sciences

Sepsis, or the organ damage that ensues after the body fails to properly contain a local infection, is the leading cause of in-patient hospitalization in the United States. Advances in critical care medicine over the last 20 years have enabled most sepsis patients to survive the life-threatening dysregulated immune response. However, a majority of survivors report chronic weakness and fatigue years after sepsis, and the cause of this weakness remains largely unknown. This dissertation work focused first on elucidating the major causes of post-sepsis muscle weakness (Aim 1). This aim involved a time-course study to determine when muscle weakness was …