Medical Molecular Biology Commons^™

Ca2+ Efflux Facilitated By Co-Transport Of Inorganic Phosphate Anion In The H+/Ca2+ Antiporter Yfke, Wei Niu, Wenchang Zhou, Shuo Lu, Trung Vu, Vasanthi Jayaraman, José D Faraldo-Gómez, Lei Zheng

Faculty, Staff and Student Publications

Ca2+ is an important signaling messenger. In microorganisms, fungi, and plants, H+/Ca2+ antiporters (CAX) are known to play key roles in the homeostasis of intracellular Ca2+ by catalyzing its efflux across the cell membrane. Here, we reveal that the bacterial CAX homolog YfkE transports Ca2+ in two distinct modes: a low-flux H+/Ca2+ exchange mode and a high-flux mode in which Ca2+ and phosphate ions are co-transported (1:1) in exchange for H+. Coupling with phosphate greatly accelerates the Ca2+ efflux activity of YfkE. Our studies reveal that Ca2+ and phosphate bind to adjacent sites in a central translocation pathway and lead …

An Unknown Essential Function Of Trna Splicing Endonuclease Is Linked To The Integrated Stress Response And Intron Debranching, Jennifer E Hurtig, Ambro Van Hoof

Faculty, Staff and Student Publications

tRNA splicing endonuclease (TSEN) has a well-characterized role in transfer RNA (tRNA) splicing but also other functions. For yeast TSEN, these other functions include degradation of a subset of mRNAs that encode mitochondrial proteins and an unknown essential function. In this study, we use yeast genetics to characterize the unknown tRNA-independent function(s) of TSEN. Using a high-copy suppressor screen, we found that sen2 mutants can be suppressed by overexpression of SEN54. This effect was seen both for tRNA-dependent and tRNA-independent functions indicating that SEN54 is a general suppressor of sen2, likely through structural stabilization. A spontaneous suppressor screen identified mutations …

Kras-Dependency In Pancreatic Ductal Adenocarcinoma: Mechanisms Of Escaping In Resistance To Kras Inhibitors And Perspectives Of Therapy, Enrico Gurreri, Giannicola Genovese, Luigi Perelli, Antonio Agostini, Geny Piro, Carmine Carbone, Giampaolo Tortora

Faculty, Staff and Student Publications

Pancreatic ductal adenocarcinoma (PDAC) is still one of the deadliest cancers in oncology because of its increasing incidence and poor survival rate. More than 90% of PDAC patients are KRAS mutated (KRASmu), with KRASG12D and KRASG12V being the most common mutations. Despite this critical role, its characteristics have made direct targeting of the RAS protein extremely difficult. KRAS regulates development, cell growth, epigenetically dysregulated differentiation, and survival in PDAC through activation of key downstream pathways, such as MAPK-ERK and PI3K-AKT-mammalian target of rapamycin (mTOR) signaling, in a KRAS-dependent manner. KRASmu induces the occurrence of acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial …

Sequential Absorption Of Two Photons Creates A Bistable Form Of Rubyacr Responsible For Its Strong Desensitization, Oleg A Sineshchekov, Elena G Govorunova, Hai Li, Yumei Wang, John L Spudich

Faculty, Staff and Student Publications

Channelrhodopsins with red-shifted absorption, rare in nature, are highly desired for optogenetics because light of longer wavelengths more deeply penetrates biological tissue. RubyACRs (Anion ChannelRhodopsins), a group of four closely related anion-conducting channelrhodopsins from thraustochytrid protists, are the most red-shifted channelrhodopsins known with absorption maxima up to 610 nm. Their photocurrents are large, as is typical of blue- and green-absorbing ACRs, but they rapidly decrease during continuous illumination (desensitization) and extremely slowly recover in the dark. Here, we show that long-lasting desensitization of RubyACRs results from photochemistry not observed in any previously studied channelrhodopsins. Absorption of a second photon by …

Starvation Sensing By Mycobacterial Rela/Spot Homologue Through Constitutive Surveillance Of Translation, Yunlong Li, Soneya Majumdar, Ryan Treen, Manjuli R. Sharma, Jamie Corro, Howard B. Gamper, Swati R. Manjari, Jerome Prusa, Nilesh K. Banavali, Christina L. Stallings, Ya-Ming Hou, Rajendra K. Agrawal, Anil K. Ojha

Department of Biochemistry and Molecular Biology Faculty Papers

The stringent response, which leads to persistence of nutrient-starved mycobacteria, is induced by activation of the RelA/SpoT homolog (Rsh) upon entry of a deacylated-tRNA in a translating ribosome. However, the mechanism by which Rsh identifies such ribosomes in vivo remains unclear. Here, we show that conditions inducing ribosome hibernation result in loss of intracellular Rsh in a Clp protease-dependent manner. This loss is also observed in nonstarved cells using mutations in Rsh that block its interaction with the ribosome, indicating that Rsh association with the ribosome is important for Rsh stability. The cryo-EM structure of the Rsh-bound 70S ribosome in …

Immunometabolic Reprogramming, Another Cancer Hallmark, Vijay Kumar, John H. Stewart

School of Medicine Faculty Publications

Molecular carcinogenesis is a multistep process that involves acquired abnormalities in key biological processes. The complexity of cancer pathogenesis is best illustrated in the six hallmarks of the cancer: (1) the development of self-sufficient growth signals, (2) the emergence of clones that are resistant to apoptosis, (3) resistance to the antigrowth signals, (4) neo-angiogenesis, (5) the invasion of normal tissue or spread to the distant organs, and (6) limitless replicative potential. It also appears that non-resolving inflammation leads to the dysregulation of immune cell metabolism and subsequent cancer progression. The present article delineates immunometabolic reprogramming as a critical hallmark of …

Changes In Nascent Chromatin Structure Regulate Activation Of The Pro-Fibrotic Transcriptome And Myofibroblast Emergence In Organ Fibrosis, Morgan D. Basta, Svetlana Petruk, Ross Summer, Joel Rosenbloom, Peter J. Wermuth, Edward J. Macarak, Alex V. Levin, Alexander Mazo, Janice L. Walker

Department of Biochemistry and Molecular Biology Faculty Papers

Cell reprogramming to a myofibroblast responsible for the pathological accumulation of extracellular matrix is fundamental to the onset of fibrosis. Here, we explored how condensed chromatin structure marked by H3K72me3 becomes modified to allow for activation of repressed genes to drive emergence of myofibroblasts. In the early stages of myofibroblast precursor cell differentiation, we discovered that H3K27me3 demethylase enzymes UTX/KDM6B creates a delay in the accumulation of H3K27me3 on nascent DNA revealing a period of decondensed chromatin structure. This period of decondensed nascent chromatin structure allows for binding of pro-fibrotic transcription factor, Myocardin-related transcription factor A (MRTF-A) to nascent DNA. …

Candida Albicans Hyphal Morphogenesis Within Macrophages Does Not Require Carbon Dioxide Or Ph-Sensing Pathways, Hannah B Wilson, Michael C Lorenz

Faculty, Staff and Student Publications

The opportunistic fungal pathogen Candida albicans has evolved a variety of mechanisms for surviving inside and escaping macrophages, including the initiation of filamentous growth. Although several distinct models have been proposed to explain this process at the molecular level, the signals driving hyphal morphogenesis in this context have yet to be clarified. Here, we evaluate the following three molecular signals as potential hyphal inducers within macrophage phagosomes: CO2, intracellular pH, and extracellular pH. Additionally, we revisit previous work suggesting that the intracellular pH of C. albicans fluctuates in tandem with morphological changes in vitro. Using time-lapse microscopy, we observed …

Ragd Auto-Activating Mutations Impair Mit/Tfe Activity In Kidney Tubulopathy And Cardiomyopathy Syndrome, Irene Sambri, Marco Ferniani, Giulia Campostrini, Marialuisa Testa, Viviana Meraviglia, Mariana E G De Araujo, Ladislav Dokládal, Claudia Vilardo, Jlenia Monfregola, Nicolina Zampelli, Francesca Del Vecchio Blanco, Annalaura Torella, Carolina Ruosi, Simona Fecarotta, Giancarlo Parenti, Leopoldo Staiano, Milena Bellin, Lukas A Huber, Claudio De Virgilio, Francesco Trepiccione, Vincenzo Nigro, Andrea Ballabio

Duncan NRI Faculty and Staff Publications

Heterozygous mutations in the gene encoding RagD GTPase were shown to cause a novel autosomal dominant condition characterized by kidney tubulopathy and cardiomyopathy. We previously demonstrated that RagD, and its paralogue RagC, mediate a non-canonical mTORC1 signaling pathway that inhibits the activity of TFEB and TFE3, transcription factors of the MiT/TFE family and master regulators of lysosomal biogenesis and autophagy. Here we show that RagD mutations causing kidney tubulopathy and cardiomyopathy are "auto- activating", even in the absence of Folliculin, the GAP responsible for RagC/D activation, and cause constitutive phosphorylation of TFEB and TFE3 by mTORC1, without affecting the phosphorylation …

Clinical Characteristics And Survival Of Pulmonary Arterial Hypertension With Or Without Interstitial Lung Disease In Systemic Sclerosis, Jessica L Fairley, Dylan Hansen, Laura Ross, Susanna Proudman, Joanne Sahhar, Gene-Siew Ngian, Jennifer Walker, Lauren V Host, Kathleen Morrisroe, Diane Apostolopoulous, Nava Ferdowsi, Michelle Wilson, Maryam Tabesh, Wendy Stevens, Mandana Nikpour

Faculty, Staff and Student Publications

Objectives

To describe the clinical phenotype and prognosis of people in the Australian Scleroderma (SSc) Cohort Study with pulmonary arterial hypertension (PAH) with or without interstitial lung disease (ILD).

Methods

Participants meeting ACR/EULAR criteria for SSc were divided into four mutually exclusive groups: those meeting criteria for PAH (PAH-only), ILD (ILD-only), concurrent PAH and ILD (PAH-ILD) or neither PAH nor ILD (SSc-only). Logistic or linear regression analyses were used for associations between clinical features, health-related quality of life (HRQoL) and physical function. Survival analysis was performed using Kaplan–Meier estimates and Cox-regression modelling.

Results

Of 1561 participants, 7% fulfilled criteria for …

Functional Neuronal Circuits Promote Disease Progression In Cancer, Anthony C Restaino, Austin Walz, Samuel J Vermeer, Jeffrey Barr, Attila Kovács, Robin R Fettig, Daniel W Vermeer, Hunter Reavis, Caitlin S Williamson, Christopher T Lucido, Tuany Eichwald, Dalia K Omran, Euihye Jung, Lauren E Schwartz, Maria Bell, Desirae M Muirhead, Jody E Hooper, William C Spanos, Ronny Drapkin, Sebastien Talbot, Paola D Vermeer

Faculty, Staff and Student Publications

The molecular and functional contributions of intratumoral nerves to disease remain largely unknown. We localized synaptic markers within tumors suggesting that these nerves form functional connections. Consistent with this, electrophysiological analysis shows that malignancies harbor significantly higher electrical activity than benign disease or normal tissues. We also demonstrate pharmacologic silencing of tumoral electrical activity. Tumors implanted in transgenic animals lacking nociceptor neurons show reduced electrical activity. These data suggest that intratumoral nerves remain functional at the tumor bed. Immunohistochemical staining demonstrates the presence of the neuropeptide, Substance P (SP), within the tumor space. We show that tumor cells express the …

Polymorphisms Within Autophagy-Related Genes As Susceptibility Biomarkers For Multiple Myeloma: A Meta-Analysis Of Three Large Cohorts And Functional Characterization, Esther Clavero, José Manuel Sanchez-Maldonado, Angelica Macauda, Rob Ter Horst, Belém Sampaio-Marques, Artur Jurczyszyn, Alyssa Clay-Gilmour, Angelika Stein, Michelle A T Hildebrandt, Niels Weinhold, Gabriele Buda, Ramón García-Sanz, Waldemar Tomczak, Ulla Vogel, Andrés Jerez, Daria Zawirska, Marzena Wątek, Jonathan N Hofmann, Stefano Landi, John J Spinelli, Aleksandra Butrym, Abhishek Kumar, Joaquín Martínez-López, Sara Galimberti, María Eugenia Sarasquete, Edyta Subocz, Elzbieta Iskierka-Jażdżewska, Graham G Giles, Malwina Rybicka-Ramos, Marcin Kruszewski, Niels Abildgaard, Francisco García Verdejo, Pedro Sánchez Rovira, Miguel Inacio Da Silva Filho, Katalin Kadar, Małgorzata Razny, Wendy Cozen, Matteo Pelosini, Manuel Jurado, Parveen Bhatti, Marek Dudzinski, Agnieszka Druzd-Sitek, Enrico Orciuolo, Yang Li, Aaron D Norman, Jan Maciej Zaucha, Rui Manuel Reis, Miroslaw Markiewicz, Juan José Rodríguez Sevilla, Vibeke Andersen, Krzysztof Jamroziak, Kari Hemminki, Sonja I Berndt, Vicent Rajkumar, Grzegorz Mazur, Shaji K Kumar, Paula Ludovico, Arnon Nagler, Stephen J Chanock, Charles Dumontet, Mitchell J Machiela, Judit Varkonyi, Nicola J Camp, Elad Ziv, Annette Juul Vangsted, Elizabeth E Brown, Daniele Campa, Celine M Vachon, Mihai G Netea, Federico Canzian, Asta Försti, Juan Sainz

Faculty, Staff and Student Publications

Multiple myeloma (MM) arises following malignant proliferation of plasma cells in the bone marrow, that secrete high amounts of specific monoclonal immunoglobulins or light chains, resulting in the massive production of unfolded or misfolded proteins. Autophagy can have a dual role in tumorigenesis, by eliminating these abnormal proteins to avoid cancer development, but also ensuring MM cell survival and promoting resistance to treatments. To date no studies have determined the impact of genetic variation in autophagy-related genes on MM risk. We performed meta-analysis of germline genetic data on 234 autophagy-related genes from three independent study populations including 13,387 subjects of …

The Involvement Of Ubiquitin In Med13 Cyclin C Degradation Following Cellular Stress, Ayesha Gurnani, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

The Cdk8 Kinase Module is a dissociable regulator of cellular stress response genes, with degradation of its components Med13 and cyclin C eventually determining cell fate decisions such as engaging cell survival or cell death mechanisms. We aimed to explore the roles of ubiquitin in degradation of the Cdk8 Kinase Module following nitrogen starvation, with respect to the potential involvement of deubiquitinating enzyme Doa4, lysine linkage at position K63, and E2 ubiquitin conjugating enzymes Ubc4 and Ubc5. We utilized Western blot analysis to observe nitrogen starvation-induced degradation of Med13-HA in wild-type, doa4 mutant, and K63R yeast strains; degradation of cyclin …

Identifying Co-Factors That Drive Tra-1 Activator Function, Jibran Imtiaz, Yongquan Shen, Ronald Ellis

Rowan-Virtua Research Day

Gli proteins are involved in cell fate determination, proliferation, and patterning in many species and are major effectors of Hedgehog (Hh) signaling. There are three Gli proteins in humans, and mutations or errors in their regulation lead to a variety of developmental disorders or cancer. However, the mechanisms by which they interact with co-factors are poorly understood. We are analyzing co-factors of Gli proteins using TRA-1 in Caenorhabditis nematodes. The TRA-1 zinc fingers are structurally like those of other Gli proteins, and TRA-1 can be cleaved like other Gli proteins to form a repressor. However, its function has changed during …

Loss Of Lgr5 Through Therapy-Induced Downregulation Or Gene Ablation Is Associated With Resistance And Enhanced Met-Stat3 Signaling In Colorectal Cancer Cells, Tressie A Posey, Joan Jacob, Ashlyn Parkhurst, Shraddha Subramanian, Liezl E Francisco, Zhengdong Liang, Kendra S Carmon

Faculty, Staff and Student Publications

Leucine-rich repeat-containing, G protein-coupled receptor 5 (LGR5) is highly expressed in colorectal cancer and cancer stem cells (CSCs) that play important roles in tumor initiation, progression, and metastasis. Loss of LGR5 has been shown to enhance therapy resistance. However, the molecular mechanisms that mediate this resistance remain elusive. In this study, we demonstrate conversion of LGR5+ colorectal cancer cells to an LGR5- state in response to chemotherapy, LGR5- targeted antibody-drug conjugates (ADCs), or LGR5 gene ablation led to activation of STAT3. Further investigation revealed increased STAT3 activation occurred as a result of increased mesenchymal epithelial transition (MET) factor receptor activity. …

Immunomodulatory Effects Of Resolvin D2 In A Model Of Infection, Prem Yugandhar Kadiyam Sundarasivarao

Graduate School of Biomedical Sciences Theses and Dissertations

Dysregulated hyperinflammatory host immune response to underlying bacterial infections is a characteristic of sepsis. In sepsis, bacteria often trigger abnormal hyperinflammatory responses which can cause multiple organ failure and if sustained can lead to an immunosuppressive phase where the host is susceptible to secondary infections caused by opportunistic bacteria like Pseudomonas aeruginosa (P. aeruginosa). In our studies, we used a 2-hit model of cecal ligation and puncture (CLP) followed by P. aeruginosa secondary lung infection to investigate cellular and molecular mechanisms in the beneficial action of resolvin D2 (RvD2). Resolvins of the D-series are a group of fatty acids known …

Roles For Mycobacterial Dinb2 In Frameshift And Substitution Mutagenesis, Pierre Dupuy, Shreya Ghosh, Allison Fay, Oyindamola Adefisayo, Richa Gupta, Stewart Shuman, Michael S. Glickman

Publications and Research

Translesion synthesis by translesion polymerases is a conserved mechanism of DNA damage tolerance. In bacteria, DinB enzymes are the widely distributed promutagenic translesion polymerases. The role of DinBs in mycobacterial mutagenesis was unclear until recent studies revealed a role for mycobacterial DinB1 in substitution and frameshift mutagenesis, overlapping with that of translesion polymerase DnaE2. Mycobacterium smegmatis encodes two additional DinBs (DinB2 and DinB3) and Mycobacterium tuberculosis encodes DinB2, but the roles of these polymerases in mycobacterial damage tolerance and mutagenesis is unknown. The biochemical properties of DinB2, including facile utilization of ribonucleotides and 8-oxo- guanine, suggest that DinB2 could be …

Investigating Novel Chemotherapeutics Against The Parasite Toxoplasma Gondii, Braydon Dreher

Theses/Capstones/Creative Projects

Toxoplasma gondii, an intracellular protozoan, is a globally prevalent parasite due to the infectivity of T. gondii with nearly 2.5 billion people affected worldwide. Toxoplasma gondii can cause toxoplasmosis, which is a disease acquired through the consumption of undercooked meat or found in the feces of felines, and often leads to profound neuropathology and potentially death. Currently, acute toxoplasmosis is treated with pyrimethamine and sulfadiazine, which is a combination of an antiprotozoal and a sulfonamide. This combination of drugs directly targets the acute stage of infection but has failed to eliminate or impact the chronic carriage of bradyzoites while …

Acute Kidney Injury In The Elderly, Zachary Palanza

Honors Scholar Theses

Acute kidney injury (AKI) is a significant clinical concern in the elderly, marked by heightened incidence rates, increased morbidity and mortality, and impaired kidney repair mechanisms. AKI often has severe consequences, including extended hospital stays, heightened rates of chronic kidney disease, and elevated healthcare costs. The vulnerability of elderly individuals to AKI is amplified by age-related structural and functional changes in the kidneys, reduced physiological reserve, and increased exposure to nephrotoxic agents. The impaired kidney repair mechanisms observed in the elderly pose further complexities in AKI management. With age, the regenerative capacity of the kidneys diminishes, resulting in incomplete recovery …

A Review Of Staphylococcus Aureus Pathogenesis, Global Impact, And The Rise Of Antibiotic-Resistant Clones, Anders Kleinbeck

Honors Scholar Theses

Staphylococcus aureus is a pathogen of grave concern to global public health. The pathogen has shown an unrivaled propensity to obtain resistance to nearly every antibiotic drug approved and prescribed for its treatment. This review will provide an overview of the history and evolution of S. aureus, including an analysis of its transition from the nosocomial setting to the community and the factors contributing to the species’ innate pathogenicity. This paper will also discuss the molecular mechanisms by which resistance to a wide range of popular antibiotic substances was obtained and will provide insight into the evolutionary patterns exhibited by …