Medical Biochemistry Commons^™

Characterizing The Role Of Tdg In Fxr-Dependent Signaling, Oladapo A. Onabote

Electronic Thesis and Dissertation Repository

Thymine DNA Glycosylase (TDG) plays a key role in active demethylation by excising intermediates of 5-methylcytosine. The function of TDG is required for embryonic development, as Tdg-null embryos die at E11.5. To bypass this embryonic lethality, our lab generated conditional Tdg knockout (TDG_CKO) mice. These mice develop late-onset hepatocellular carcinoma (HCC), partly due to impaired Farnesoid X Receptor (FXR) signaling. Interestingly, Fxr-knockout mice display a similar phenotype and transcriptional profile to TDG_CKO mice, prompting us to investigate a role for TDG in FXR signaling. To this end, we generated Tdg/Fxr double-knockout (DKO) mice. …

Polθ Promotes The Repair Of 5'-Dna-Protein Crosslinks By Microhomology-Mediated End-Joining, Gurushankar Chandramouly, Shuren Liao, Timur Rusanov, Nikita Borisonnik, Marissa L Calbert, Tatiana Kent, Katherine Sullivan-Reed, Umeshkumar Vekariya, Ekaterina Kashkina, Tomasz Skorski, Hong Yan, Richard T Pomerantz

Department of Biochemistry and Molecular Biology Faculty Papers

DNA polymerase θ (Polθ) confers resistance to chemotherapy agents that cause DNA-protein crosslinks (DPCs) at double-strand breaks (DSBs), such as topoisomerase inhibitors. This suggests Polθ might facilitate DPC repair by microhomology-mediated end-joining (MMEJ). Here, we investigate Polθ repair of DSBs carrying DPCs by monitoring MMEJ in Xenopus egg extracts. MMEJ in extracts is dependent on Polθ, exhibits the MMEJ repair signature, and efficiently repairs 5' terminal DPCs independently of non-homologous end-joining and the replisome. We demonstrate that Polθ promotes the repair of 5' terminal DPCs in mammalian cells by using an MMEJ reporter and find that Polθ confers resistance to …

The Evolutionary Conserved Swi/Snf Subunits Arid1a And Arid1b Are Key Modulators Of Pluripotency And Cell-Fate Determination, Luca Pagliaroli, Marco Trizzino

Department of Biochemistry and Molecular Biology Faculty Papers

Organismal development is a process that requires a fine-tuned control of cell fate and identity, through timely regulation of lineage-specific genes. These processes are mediated by the concerted action of transcription factors and protein complexes that orchestrate the interaction between cis-regulatory elements (enhancers, promoters) and RNA Polymerase II to elicit transcription. A proper understanding of these dynamics is essential to elucidate the mechanisms underlying developmental diseases. Many developmental disorders, such as Coffin-Siris Syndrome, characterized by growth impairment and intellectual disability are associated with mutations in subunits of the SWI/SNF chromatin remodeler complex, which is an essential regulator of transcription. ARID1B …

Differential Leukocyte And Platelet Profiles In Distinct Models Of Traumatic Brain Injury, William Brad Hubbard, Meenakshi Banerjee, Hemendra J. Vekaria, Kanakanagavalli Shravani Prakhya, Smita Joshi, Qingjun Wang, Kathryn E. Saatman, Sidney W. Whiteheart, Patrick G. Sullivan

Spinal Cord and Brain Injury Research Center Faculty Publications

Traumatic brain injury (TBI) affects over 3 million individuals every year in the U.S. There is growing appreciation that TBI can produce systemic modifications, which are in part propagated through blood–brain barrier (BBB) dysfunction and blood–brain cell interactions. As such, platelets and leukocytes contribute to mechanisms of thromboinflammation after TBI. While these mechanisms have been investigated in experimental models of contusion brain injury, less is known regarding acute alterations following mild closed head injury. To investigate the role of platelet dynamics and bioenergetics after TBI, we employed two distinct, well-established models of TBI in mice: the controlled cortical impact (CCI) …

Three-Dimensional Structure Of Human Cyclooxygenase (Hcox)-1., Morena Miciaccia, Benny Danilo Belviso, Mariaclara Iaselli, Gino Cingolani, Savina Ferorelli, Marianna Cappellari, Paola Loguercio Polosa, Maria Grazia Perrone, Rocco Caliandro, Antonio Scilimati

Department of Biochemistry and Molecular Biology Faculty Papers

The beneficial effects of Cyclooxygenases (COX) inhibitors on human health have been known for thousands of years. Nevertheless, COXs, particularly COX-1, have been linked to a plethora of human diseases such as cancer, heart failure, neurological and neurodegenerative diseases only recently. COXs catalyze the first step in the biosynthesis of prostaglandins (PGs) and are among the most important mediators of inflammation. All published structural work on COX-1 deals with the ovine isoenzyme, which is easier to produce in milligram-quantities than the human enzyme and crystallizes readily. Here, we report the long-sought structure of the human cyclooxygenase-1 (hCOX-1) that we refined …

A Bisphosphonate With A Low Hydroxyapatite Binding Affinity Prevents Bone Loss In Mice After Ovariectomy And Reverses Rapidly With Treatment Cessation, Abigail A. Coffman, Jelena Basta-Pljakic, Rosa M. Guerra, Frank H. Ebetino, Mark W. Lundy, Robert J. Majeska, Mitchell B. Schaffler

Publications and Research

Bisphosphonates (BPs) are a mainstay of osteoporosis treatment; however, concerns about bone health based on oversuppression of remodeling remain. Long-term bone remodeling suppression adversely affects bone material properties with microdamage accumulation and reduced fracture toughness in animals and increases in matrix mineralization and atypical femur fractures in patients. Although a “drug holiday” from BPs to restore remodeling and improve bone quality seems reasonable, clinical BPs have long functional half-lives because of their high hydroxyapatite (HAP) binding affinities. This places a practical limit on the reversibility and effectiveness of a drug holiday. BPs with low HAP affinity and strong osteoclast inhibition …

Dna Mismatch Repair And Its Role In Huntington's Disease, Ravi R Iyer, Anna Pluciennik

Department of Biochemistry and Molecular Biology Faculty Papers

DNA mismatch repair (MMR) is a highly conserved genome stabilizing pathway that corrects DNA replication errors, limits chromosomal rearrangements, and mediates the cellular response to many types of DNA damage. Counterintuitively, MMR is also involved in the generation of mutations, as evidenced by its role in causing somatic triplet repeat expansion in Huntington's disease (HD) and other neurodegenerative disorders. In this review, we discuss the current state of mechanistic knowledge of MMR and review the roles of key enzymes in this pathway. We also present the evidence for mutagenic function of MMR in CAG repeat expansion and consider mechanistic hypotheses …

Label‑Free Spectral Imaging To Study Drug Distribution And Metabolism In Single Living Cells, Qamar Alshammari, Rajasekharreddy Pala, Nir Katzir, Surya M. Nauli

Pharmacy Faculty Articles and Research

During drug development, evaluation of drug and its metabolite is an essential process to understand drug activity, stability, toxicity and distribution. Liquid chromatography (LC) coupled with mass spectrometry (MS) has become the standard analytical tool for screening and identifying drug metabolites. Unlike LC/MS approach requiring liquifying the biological samples, we showed that spectral imaging (or spectral microscopy) could provide high-resolution images of doxorubicin (dox) and its metabolite doxorubicinol (dox’ol) in single living cells. Using this new method, we performed measurements without destroying the biological samples. We calculated the rate constant of dox translocating from extracellular moiety into the cell and …

Distinct Mechanisms Control Genome Recognition By P53 At Its Target Genes Linked To Different Cell Fates., Marina Farkas, Hideharu Hashimoto, Yingtao Bi, Ramana V Davuluri, Lois Resnick-Silverman, James J. Manfredi, Erik W. Debler, Steven B. Mcmahon

Department of Biochemistry and Molecular Biology Faculty Papers

The tumor suppressor p53 integrates stress response pathways by selectively engaging one of several potential transcriptomes, thereby triggering cell fate decisions (e.g., cell cycle arrest, apoptosis). Foundational to this process is the binding of tetrameric p53 to 20-bp response elements (REs) in the genome (RRRCWWGYYYN_0-13RRRCWWGYYY). In general, REs at cell cycle arrest targets (e.g. p21) are of higher affinity than those at apoptosis targets (e.g., BAX). However, the RE sequence code underlying selectivity remains undeciphered. Here, we identify molecular mechanisms mediating p53 binding to high- and low-affinity REs by showing that key determinants of the code are embedded …

A Peek Inside The Machines Of Bacterial Nucleotide Excision Repair, Thanyalak Kraithong, Silas Hartley, David Jeruzalmi, Danaya Pakotiprapha

Publications and Research

Double stranded DNA (dsDNA), the repository of genetic information in bacteria, archaea and eukaryotes, exhibits a surprising instability in the intracellular environment; this fragility is exacerbated by exogenous agents, such as ultraviolet radiation. To protect themselves against the severe consequences of DNA damage, cells have evolved at least six distinct DNA repair pathways. Here, we review recent key findings of studies aimed at understanding one of these pathways: bacterial nucleotide excision repair (NER). This pathway operates in two modes: a global genome repair (GGR) pathway and a pathway that closely interfaces with transcription by RNA polymerase called transcription-coupled repair (TCR). …

Insights Into Genome Recoding From The Mechanism Of A Classic +1-Frameshifting Trna., Howard Gamper, Haixing Li, Isao Masuda, D. Miklos Robkis, Thomas Christian, Adam B. Conn, Gregor Blaha, E. James Petersson, Ruben L. Gonzalez, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

While genome recoding using quadruplet codons to incorporate non-proteinogenic amino acids is attractive for biotechnology and bioengineering purposes, the mechanism through which such codons are translated is poorly understood. Here we investigate translation of quadruplet codons by a +1-frameshifting tRNA, SufB2, that contains an extra nucleotide in its anticodon loop. Natural post-transcriptional modification of SufB2 in cells prevents it from frameshifting using a quadruplet-pairing mechanism such that it preferentially employs a triplet-slippage mechanism. We show that SufB2 uses triplet anticodon-codon pairing in the 0-frame to initially decode the quadruplet codon, but subsequently shifts to the +1-frame during tRNA-mRNA translocation. SufB2 …

Tumor Microenvironment: An Evil Nexus Promoting Aggressive Head And Neck Squamous Cell Carcinoma And Avenue For Targeted Therapy, Ajaz A. Bhat, Parvaiz Yousuf, Nissar A. Wani, Arshi Rizwan, Shyam S. Chauhan, Mushtaq A. Siddiqi, Davide Bedognetti, Wael El-Rifai, Michael P. Frenneaux, Surinder K. Batra, Mohammad Haris, Muzafar A. Macha

Journal Articles: Biochemistry & Molecular Biology

Head and neck squamous cell carcinoma (HNSCC) is a very aggressive disease with a poor prognosis for advanced-stage tumors. Recent clinical, genomic, and cellular studies have revealed the highly heterogeneous and immunosuppressive nature of HNSCC. Despite significant advances in multimodal therapeutic interventions, failure to cure and recurrence are common and account for most deaths. It is becoming increasingly apparent that tumor microenvironment (TME) plays a critical role in HNSCC tumorigenesis, promotes the evolution of aggressive tumors and resistance to therapy, and thereby adversely affects the prognosis. A complete understanding of the TME factors, together with the highly complex tumor-stromal interactions, …

Myc Regulates Ribosome Biogenesis And Mitochondrial Gene Expression Programs Through Its Interaction With Host Cell Factor-1., Tessa M. Popay, Jing Wang, Clare M. Adams, Gregory Caleb Howard, Simona G. Codreanu, Stacy D. Sherrod, John A. Mclean, Lance R. Thomas, Shelly L. Lorey, Yuichi J. Machida, April M. Weissmiller, Christine M. Eischen, Qi Liu, William P. Tansey

Department of Cancer Biology Faculty Papers

The oncoprotein transcription factor MYC is a major driver of malignancy and a highly validated but challenging target for the development of anticancer therapies. Novel strategies to inhibit MYC may come from understanding the co-factors it uses to drive pro-tumorigenic gene expression programs, providing their role in MYC activity is understood. Here we interrogate how one MYC co-factor, host cell factor (HCF)-1, contributes to MYC activity in a human Burkitt lymphoma setting. We identify genes connected to mitochondrial function and ribosome biogenesis as direct MYC/HCF-1 targets and demonstrate how modulation of the MYC-HCF-1 interaction influences cell growth, metabolite profiles, global …

Carnosic Acid Differentially Modulates The Nrf2- Antioxidant Response In Male And Female Mice Following Experimental Traumatic Brain Injury, Jacob A. Dunkerson

Theses and Dissertations--Neuroscience

Traumatic brain injury (TBI) is a leading cause of death and disability in the United States. Each year, an estimated 2.8 million Americans are diagnosed with a TBI due to falling, motor vehicle collisions, gun violence, and sports related concussions. Although inflicted by a single event, the post-traumatic effects of TBI often develop into a life-long disease. Survivors often experience cognitive decline, memory loss, emotional instability, changes in personality, and physical disabilities. A single TBI, and more-so repetitive TBI's, place an individual at a greater risk of developing chronic neurological disorders, such as dementia or Alzheimer’s disease, earlier in life. …

Entry And Early Infection Of Non-Segmented Negative Sense Rna Viruses, Jean Mawuena Branttie

Theses and Dissertations--Molecular and Cellular Biochemistry

Paramyxoviruses, pneumoviruses, and other non-segmented negative sense (NNS) RNA viruses have historically been of public health concern. Although their genomes are typically small (up to 19kbs) they are able to inflict large-scale detrimental pathologies on host cells. Human metapneumovirus (HMPV) is a widespread pathogen and is a NNS RNA virus. HMPV results respiratory tract infections and is particularly dangerous for preterm infants, the elderly, and immunocompromised individuals. Other viruses within the NNS RNA virus order include the deadly Ebola, Hendra, and Nipah viruses (EBOV, HeV, and NiV), as well as the re-emerging measles virus (MeV). Despite their public impact, there …

The Role Of Vascular Endothelial Growth Factor In Leukemia Trafficking, Shaw Powell

Theses and Dissertations--Medical Sciences

Vascular endothelial growth factor (VEGF) is a signaling protein involved in inducing and regulating endothelial cell proliferation and function (Duffy et al 2000). VEGF is also involved in cancer progression, as it induces vascular permeability and promotes angiogenesis to tumor laden areas, giving cancer cells critical oxygen and nutrients (Hoeppner et al.,2012. Studies indicate VEGF prevents lymphoblast apoptosis, which may contribute to leukemia formation and enable the proliferation of leukemic cells (Duffy et al 2000). Ongoing research seeks to further examine VEGF in leukemia, using a rag2:GFP-Myc expressing transgenic zebrafish as the animal model of T-cell Acute Lymphoblastic Leukemia (T-ALL). …

A Biochemical Characterization Of The Fusion Proteins From Enveloped Rna Viruses, Chelsea T. Barrett

Theses and Dissertations--Molecular and Cellular Biochemistry

Enveloped viruses must bind target cells and then fuse the viral membrane with a cell membrane to enter a host cell. These viruses use one or more surface glycoproteins to carry out these critical functions. The surface glycoprotein that carries out the fusion function, termed a fusion protein, is divided into three classes based on structural similarities. Some of the most studied human viral pathogens, such as human immunodeficiency virus (HIV), Ebola virus, influenza, measles, and the recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), possess class I fusion proteins. Following synthesis, class I fusion proteins associate as non-covalently …

Pre-Clinical Advancements In Biomarkers, Tools, And Therapeutics For A Metabolic Neurodegenerative Disease, Zoë Simmons

Theses and Dissertations--Molecular and Cellular Biochemistry

Glycogen is the storage form of glucose and a highly important substrate for cellular metabolism. Characterization of the enzymes and mechanisms of glycogen metabolism began over 70 years ago and over the last 20 years, a previously unknown protein called laforin has emerged as an important contributor to glycogen metabolism homeostasis. Multiple labs demonstrated that laforin is a glycogen phosphatase and mutations in the gene encoding laforin cause the formation of aberrant glycogen-like aggregates called Lafora bodies (LBs). LBs are cytoplasmic, water-insoluble aggregates that drive neurodegeneration and early death in Lafora disease (LD) patients. The direct relationship between mutated laforin, …

Notch Signaling Regulates Perivascular Adipose Tissue (Pvat) Function During Diet-Induced Obesity, C Yang, A Harrington, L Ryzhova, L Liaw

Costas T. Lambrew Research Retreat 2021

Objectives:

-To test the hypothesis that canonical Notch signaling influence vascular function by regulating PVAT-derived vascular relaxation factors.

-To determine how overexpression of Notch signaling or loss of the key Notch signaling component influence PVAT function.

The Current Landscape Of Antibody-Based Therapies In Solid Malignancies, Ashu Shah, Sanchita Rauth, Abhijit Aithal, Sukhwinder Kaur, Koelina Ganguly, Catherine Orzechowski, Grish C. Varshney, Maneesh Jain, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

Over the past three decades, monoclonal antibodies (mAbs) have revolutionized the landscape of cancer therapy. Still, this benefit remains restricted to a small proportion of patients due to moderate response rates and resistance emergence. The field has started to embrace better mAb-based formats with advancements in molecular and protein engineering technologies. The development of a therapeutic mAb with long-lasting clinical impact demands a prodigious understanding of target antigen, effective mechanism of action, gene engineering technologies, complex interplay between tumor and host immune system, and biomarkers for prediction of clinical response. This review discusses the various approaches used by mAbs for …