Research into the functions of RNA in the cell.
Labs In This Area
Role of mitochondria and metabolic processes in cancer growth, cardiac disease and metabolic disorders
Characterization of cellular and mitochondrial iron regulation
Our lab has identified a novel mitochondrial protein, ATP-Binding Cassette-B8 (ABCB8), that plays a role in mitochondrial iron homeostasis and mitochondrial iron export. Mice with ABCB8 knocked out in the heart develop cardiomyopathy and mitochondrial iron accumulation. In addition, we have shown that a pathway involving mTOR and tristetraprolin, treatment with doxorubicin (an anticancer drug that also causes cardiomyopathy), and SIRT2 protein also impact cellular and/or mitochondrial iron regulation. Current studies in this area include: 1) further characterization of ABCB8 in iron homeostasis in other organs and disorders, 2) characterization of the mechanism for iron regulation by SIRT2, 3) identification of the mechanisms of iron-mediated cell death that is independent of reactive oxygen species, 4) role of iron in viral infection, particularly HIV, 5) identification of the role of Augmenter of Liver Regeneration (ALR) in cellular iron homeostasis, and 6) identification of novel mitochondrial-specific iron chelators.
Functional characterization of sucrose nonfermenting-1 (NSF1) related kinase (SNRK)
SNRK is a novel protein with sequence homology to AMP kinases, but its function is not yet delineated. We have shown that SNRK inhibits cellular proliferation by blocking the beta-catenin pathway. Transgenic mice that overexpress SNRK in the heart show improved cardiac efficiency by decreasing mitochondrial proton leakage and show protection against ischemia-induced damage through a Trib3-UCP3 pathway. Current studies in this area include: 1) characterization of the effects of SNRK knockout in cancer growth, 2) elucidation of the role of SNRK in cardiac metabolism in SNRK knockouts, and 3) role of SNRK in metabolic diseases such as diabetes.
Characterization of the role of tristetraprolin (TTP) in cellular and systemic metabolism
TTP is a protein that binds to AU-rich regions in the 3’ UTR of mRNA molecules and causes their degradation. It has been studied extensively in the field of inflammation, and we recently showed that it also plays a role in cellular iron conservation. We also have evidence that TTP is a key mediator in cellular metabolic processes. We have TTP knockout mice in the background of TNF-alpha receptor 1/2 knockout mice (to reduce the inflammatory burden). Current studies include: 1) role of TTP in liver metabolism of fatty acids and glucose, 2) role of TTP in iron-mediated systemic iron, 3) effects of TTP on mitochondrial proteins, and 4) role of TTP in systemic iron deprivations.
For more information, see Dr. Ardehali's faculty profile.
See Dr. Ardehali's publications in PubMed.
Investigating dopamine neurogenesis and subtypes; studying the role of microRNAs in Schwann cell (SC) differentiation.
Topic 1. Mechanisms underlying dopamine neurogenesis
The floor plate, the ventral organizing center in the embryonic neural tube, patterns the neural tube by secreting the potent morphogen Shh. Using genetic fate mapping, we have recently shown that the midbrain floor plate, unlike the hindbrain and spinal cord floor plate, is neurogenic and is the source of midbrain dopamine neurons (Joksimovic, et al, 2009 Nature Neuroscience, Joksimovic et al. 2009 PNAS). We are interested in understanding pathways that are involved in floor plate neurogenesis and production of dopamine neurons. We have shown that Wnt signaling is critical for the establishment of the dopamine progenitor pool and that miRNAs may modulate the dosage and timing of the Wnt pathway (Anderegg et al, PloS Genetics 2013).
Topic 2. Deconstructing Dopaminergic Diversity
The neurotransmitter dopamine, produced mainly by midbrain dopaminergic neurons, influences a spectrum of behaviors including motor, learning, reward, motivation, and cognition. In accordance with its diverse functions, dopaminergic dysfunction is implicated in a range of disorders affecting millions of people, including Parkinson’s disease (PD), schizophrenia, addiction, and depression. How a small group of neurons underpins a gamut of key behaviors and diseases remains enigmatic. We postulated that there must exist several molecularly distinct dopaminergic neuron populations that, in part, can account for the plethora of dopaminergic functions and disorders. We are currently working to test this hypothesis and define dopamine neuron subtypes.
Topic 3. MicroRNAs in Schwann cell (SC) differentiation
MicroRNAs, by modulating gene expression, have been implicated as regulators of various cellular and physiological processes including differentiation, proliferation, and cancer. We have studied the role of microRNAs in Schwann cell (SC) differentiation by conditional removal of the microRNA processing enzyme, Dicer1 (Yun et al, 2010, J Neurosci) . We reveal that mice lacking Dicer1 in SC (Dicer1 cKO) display a severe neurological phenotype resembling congenital hypomyelination. SC lacking Dicer1 are stalled in differentiation at the promyelinating state and fail to myelinate axons. We are beginning to determine the molecular basis of this phenotype. Understanding this will be important not only for congenital hypomyelination, but also for peripheral nerve regeneration and SC cancers.
For more information, please see Dr. Awatramani's faculty profile.
View Dr. Awatramani's complete list of publications in PubMed.
Rajeshwar Awatramani, PhD at 312-503-0690
Research Assistant Professor
Milan Joksimovic, Assistant Professor, Medical College of Wisconsin
Angela Anderegg, postdoctoral fellow
Natalya Cherepanova, MSTP student, U. Iowa
Meera Patel, graduate student, U. of Chicago
Cancer stem cell biology, cellular signaling and therapy responses in human brain tumors, in particular, glioblastoma (GBM)
Integrated genomic analysis by TCGA revealed tat GBMs can be classified into four clinically relevant subtypes, proneural (PN), neural, mesenchymal (Mes) and classical GBMs with each characterized by distinct gene expression signatures and genetic alterations. We reported that PN and Mes glioma stem cells (GSCs) subtypes also have distinct dysregulated signaling pathways. Our current research focuses on novel mechanisms/cellular signaling of GSC biology, tumorigenesis, progression, invasion/metastasis, angiogenesis and therapy responses of GSCs and GBMs.
1. MicroRNAs (miRs) and non-coding RNAs in GSCs and GBMs – miRs and other small non-coding RNAs act as transcription repressors or inducers of gene expression or functional modulators in all multicellular organisms. Dysregulated miRs/noncoding RNAs plays critical roles in cancer initiation, progression and responses to therapy. We study the mechanisms by which deregulated expression of miRs influence GBM malignant phenotypes through interaction with signaling pathways, that in turn, influence proneural (PN)- and mesenchymal (Mes)-associated gene expression in GSCs and GBM phenotypes. We study the molecular consequences and explore clinical applications of modulating miRs and signaling pathways in GBMs. We are establishing profiles of non-coding RNAs in these GSCs and study mechanisms and biological influences of these non-coding RNAs in regulating GSC biology and GBM phenotypes. In addition, we explore novel therapeutic approaches of delivery of tumor suppressive miRs into GSC brain xenografts in animals.
2. Autophagy in GBMs. (Macro)autophagy is an evolutionally conserved dynamic process whereby cells catabolize damaged proteins and organelles in a lysosome-dependent manner. Autophagy principally serves as an adaptive role to protect cells and tissues, including those associated with cancer. Autophagy in response to multiple stresses including therapeutic treatments such as radiation and chemotherapies provides a mechanism for tumor cell to survive and acquire resistance to therapies. Tumors can use autophagy to support and sustain their proliferation, survival, metabolism, invasiveness, metastasis, and resistance to therapy. We study mechanisms by which phosphorylation, acetylation and ubiquitination of autophagy proteins regulate GSC and GBM phenotypes and autophagic response, which, in turn contributes to tumor cell survival, growth and resistance to therapy. We investigate whether disruption of these post-translational processes on autophagy proteins inhibits autophagy and enhances the efficacy of combination therapies for GBMs. We examine whether cross-talks between miRs, autophagy and oncogenic signaling pathways regulate GSC stemness and phenotypes.
3. Heterogeneity, epigenetic regulation, DNA damage and metabolic pathways in GSCs and GBMs. Intratumoral heterogeneity is a characteristic of GBMs and most of cancers. Phenotypic and functional heterogeneity arise among GBM cells within the same tumor as a consequence of genetic change, environmental differences and reversible changes in cell properties. Subtype mosaicism within the same tumor and spontaneous conversion of human PN to Mes tumors have been observed in clinical GBMs. We explore an emerging epigenetic marker with distinct functions such as DNA methylation together with genetic mapping of these markers to assess their contributions to GBM heterogeneity. In addition, compared with PN GSCs, DNA damage and glycolytic pathways are aberrant active in Mes GSCs. We investigate the mechanisms by which these pathways regulate GSC and GBM phenotypes and responses to therapies.
4. Oncogenic receptor tyrosine kinase (RTKs) signaling, small Rho GTPase regulators in GBM and GSCs: Small Rho GTPases such as Rac1 and Cdc42 modulate cancer cell migration, invasion, growth and survival. Recently, we described mechanisms by which EGFR and its mutant EGFRvIII, and PDGFR alpha promote glioma growth and invasion by distinct mechanisms involving phosphorylation of Dock180, a Rac-specific guanidine nucleotide exchange factor (GEF) and DCBLD2, an orphan membrane receptor. We are currently investigating involvement of other modulators/GEFs and other Rho GTPases in modulating GSC and GBM phenotypes and responses to therapy.
View Dr. Cheng's complete list of publications in PubMed.
Shi-Yuan Cheng, PhD at 312-503-5314
Visit us on campus in the Lurie Building, Room 6-119, 303 E Superior Street, Chicago, Illinois 60611.
Research Associate Professor
Namratha Sastry (rotating)
Targets and functions of miRNAs encoded by the human herpesvirus Kaposi’s sarcoma-associated herpesvirus (KSHV)
Viruses commonly modify their cellular environment to optimize viral replication and persistence. Much has been learned about the intervention of viral proteins with cellular pathways. More recently, it has become clear that herpesviruses also encode large numbers of microRNAs (miRNAs). The modest amount of space miRNA precursors occupy in the viral genome, their lack of immunogenicity and their potential as regulators of gene expression make miRNAs ideal candidates for viral effectors.
The lab’s research focuses on identifying targets and functions of miRNAs encoded by the human herpesvirus Kaposi’s sarcoma-associated herpesvirus (KSHV). KSHV causes cancer in immuno-compromised individuals. The clinically most relevant KSHV-induced disease is Kaposi’s sarcoma (KS), a complex tumor driven by KSHV-infected endothelial cells. Due to the AIDS epidemic, KS has become the most common cancer in parts of Africa. KSHV also infects B lymphocytes and can consequently cause B cell lymphomas, including primary effusion lymphoma (PEL). KSHV constitutively expresses viral miRNAs from 12 precursors, suggesting a role of these miRNAs in viral replication and pathogenesis.
My lab is currently pursuing the comprehensive identification of mRNA targets of these miRNAs in primary effusion lymphoma cell lines and KSHV-infected endothelial cells. Our data suggest that, together, the KSHV miRNAs directly target hundreds of cellular mRNAs encoding proteins with roles in several different biological pathways. Our goal is to use this knowledge to characterize the most important functions of the KSHV miRNAs.
See Dr. Gottwein's publications on PubMed.
Contact Dr. Gottwein at 312-503-3075 or the lab at 312-503-3076.
Studying the posttranscriptional regulation of intronless viral messages
We study the posttranscriptional regulation of intronless viral messages. Intronless messages must be efficiently processed in the absence of splicing. Therefore, intronless messages must uncouple RNA processing and export from the splicing process making a simpler model system. We are currently focused on the posttranscriptional regulatory element (PRE) of the Hepadnaviruses, including hepatitis B virus (HBV) and woodchuck hepatitis virus (WPRE). Our goal is to understand the novel mechanism of the stimulation of heterologous gene expression by the WPRE. Understanding WPRE function will allow the development of even more efficient gene expression for a variety of applications from gene therapy to large scale protein production.
Although much is known about the molecular biology of HIV, little is known about the details of interactions between the virus and cellular components such as the cytoskeleton. To gain insights into these processes we are combining the disciplines of virology and cell biology to develop the field of cellular virology. We are especially excited by new methods we have developed – such as time-lapse analysis and fluorescent tagging – that allow for HIV to be visualized in living cells.
See Dr. Hope's publications on PubMed.
Contact Dr. Hope at 312-503-1360.
Seeking to understand the nature and function of a unique nuclear structure, the perinucleolar compartment (PNC), and its relationship with the malignant phenotype
Our studies seek to understand the nature and function of a unique nuclear structure, the perinucleolar compartment (PNC), and its relationship with the malignant phenotype. Our work looks to address the function of the PNC and its significance during malignant transformation in multiple ways.
- Determine the correlation between PNCs and cancer in tissues. In collaboration with Dr. Ann Thor at Evanston Hospital, Northwestern University, we have initiated detection of PNC in breast cancer tissues.
- Investigate the function of the PNC, its relationship with the nucleolus and rRNA synthesis. We are in the process of isolating and identifying additional proteins and RNAs in the PNC.
Identification of activities taking place in the PNC will shed light on the understanding of the function of this structure and its relationship to the nucleolus and the transformed phenotype.
For lab information and more, see Dr. Huang's faculty profile.
See Dr. Huang's publications on PubMed.
Contact Dr. Huang at 312-503-4269 or the lab at 312-503-4276.
Bacterial pathogenesis, DNA recombination mechanisms, epithelial cell adherence
Our laboratory studies the pathogenesis of Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhea. This gram-negative bacterium is an obligate human pathogen that has existed within human populations throughout recorded history. We are using a variety of molecular biological, genetic, cell biological and biochemical techniques to investigate the molecular mechanisms controlling gonococcal infection, define mechanisms and pathways of DNA recombination, replication and repair in this human specific pathogen, study the interactions between gonococci and human cells, tissues and the innate immune system, and determine how the pilus functions to help mediate genetic transfer and pathogenesis. Our goal is to discover new mechanisms important for the continued existence of this microbe in the human population to further our understanding of how infectious agents have evolved to specifically infect humans.
For lab information and more, see Dr. Seifert's faculty profile.
See Dr. Seifert's publications on PubMed.
Contact Dr. Seifert at 312-503-9788 or the lab at 312-503-9786.
Mechanisms of poxvirus and herpesvirus infection; translational control of gene expression; virus trafficking
Research in our laboratory focuses on two aspects of DNA virus biology:
1) The role of the host translation system during infection by poxviruses. Members of the poxvirus family include Variola Virus (VarV), the causative agent of smallpox, and Vaccinia Virus (VacV), a close relative that was used as a vaccine against smallpox and which has become the laboratory prototype for poxvirus research. These large double-stranded DNA viruses exhibit an impressive level of self-sufficiency and encode many of the proteins required for transcription and replication of their DNA genomes. Indeed, unlike many other DNA viruses, poxviruses do not require access to the host nucleus and replicate exclusively in the cytoplasm of infected cells within compartments termed “viral factories”. However, like all viruses, they remain dependent on gaining access to host ribosomes in order to translate their mRNAs into proteins and must also counteract host antiviral responses aimed at crippling the translation system to prevent virus replication.
Our work focuses on the function of two eukaryotic translation initiation factor (eIF) complexes, eIF3 and eIF4F, that regulate ribosome recruitment to capped mRNAs and their role in VacV infection. We have found that VacV stimulates the assembly of eIF4F complexes and that this is important for both viral protein synthesis and control of host immune responses. Furthermore, we have found that eIF3 functionally communicates with eIF4F during translation initiation, and that this plays an important role in VacV replication. We have also found that VacV redistributes key eIF4F subunits to specific regions within viral factories, a process that appears to involve the viral I3 protein.
We are currently exploring the compartmentalized replication of VacV as a means to better understand fundamental mechanisms of localized translational control and how this functions to regulate viral protein synthesis and host antiviral responses. We are also studying how the virus controls eIF4F activity by targeting upstream signaling pathways, with a particular emphasis on the metabolic sensor mammalian target of rapamycin (mTOR).
2) Microtubule regulation and function during herpes simplex virus infection. We are also interested in how herpes simplex virus type 1 (HSV-1) exploits host signaling pathways and specialized microtubule regulatory proteins, called +TIPs, to facilitate virus movement within the cell at various stages of the viral lifecycle.
See publications on PubMed.
Contact Dr. Walsh at 312-503-4292
The Wu Laboratory seeks to understand molecular mechanisms regulating gene expression and their involvement in the pathogenesis of age-related diseases, including neurodegeneration and tumor metastasis.
RNA Processing and Neurodegeneration
Accumulating evidence supports that aberrant RNA processing represents a general pathogenic mechanism for neurodegeneration, including dementia and amyotrophic lateral sclerosis (ALS). A number of RNA binding proteins (RBPs) have been associated with neurodegenerative diseases, especially various proteinopathies. Recent studies have defined TDP-43 and FUS proteinopathies, a group of heterogeneous neurodegenerative disorders overlapping with dementia, including fronto-temporal lobar degeneration (FTLD) and ALS. Several important questions drive our research: what is physiological function of these RBPs? What are the fundamental mechanisms by which genetic mutations in or aberrant regulation of these RBPs cause neural damage? What are the earliest detectable molecular and cellular events that reflect the neural damage in these devastating neurological diseases? How to reverse/repair the neural damage and slow down the progression of these devastating diseases.
To address these questions, we have established cellular and animal models for both TDP-43 and FUS proteinopathies (Li et al, 2010;Barmada et al, 2010; Chen et al, 2011; Fushimi et al, 2011). Using combined biochemical, biophysical, molecular biology and cell biology approaches, we have begun to examine the molecular pathogenic mechanisms underlying neurotoxicity induced by TDP-43 and FUS. Our recent work using atomic force microscopy (AFM), electron microscopy (EM) and (NMR) approaches has shown the biochemical, biophysical and structural similarities between TDP-43 and classical amyloid proteins (Guo et al, 2011; Xu et al, 2013; Bigio et al, 2013). Our study has defined a minimal amyloidogenic region at the carboxyl terminal domain of TDP-43 that is sufficient for amyloid fibril formation and neurotoxicity (Guo et al, 2011; Zhu et al, unpublished). Using cellular and animal models for FUS proteinopathy, we have begun to identify the earliest detectable cellular damage caused by mutations in and overexpression of the human FUS gene. Our data have provided new insights into pathogenic mechanisms underlying these proteinopathies and suggested candidate targets for developing therapeutic approaches.
A critical step in mammalian gene expression is the removal of introns by the process of pre-mRNA splicing. Alternative pre-mRNA splicing, the process of generating multiple mRNA transcripts from a single genetic locus by alternative selection of distinct splice sites, is one of most powerful mechanisms for genetic diversity and an excellent means for fine-tuning gene activity. Many genes critical for neuronal survival and function undergo extensive alternative splicing. Splicing defects play important roles in neurodegenerative disorders such as dementia and motor neuron diseases. For example, splicing mutations in the human tau gene and imbalance of tau splicing isoforms lead to fronto-temporal lobar degeneration with tau-positive pathology (FTLD-tau). To understand mechanisms underlying FTLD-tau, we have set up a model system and developed a number of biochemical, molecular and cell biological assays to study alternative splicing of the human tau gene. Our work has led to the identification of a number of cis-elements and trans-acting RBPs controlling tau alternative splicing (Kar et al, 2006; Wu et al, 2006; Kar et al, 2011; Ray et al, 2011). Our experiments have begun to reveal previously unknown players in FTLD-tau and provided new candidate target genes for developing therapeutic strategy (Donahue et al, 2006; unpublished).
Molecular Mechanisms Regulating Axon Guidance, Cell Migration & Tumor Metastasis
Another line of our research focuses on the cellular and molecular mechanisms regulating cell migration and cancer metastasis. Previous studies from our group and others led to the discovery of Slit as a prototype of neuronal guidance cue. Our studies have shown that Slit interacts with Roundabout (Robo) and acts as a chemorepellent for axons and migrating neurons (Wu et al, 1999; Li et al, 1999;Yuasa-Kawada et al, 2009). Our work has demonstrated that Slit-Robo signaling modulates chemokines and inhibits migration of different types of cells, including cancer cells. The observation that Slit is frequently inactivated in a range of tumors suggests an important role of Slit in tumor suppression. We have established several assays and shown that Slit inhibits invasion and migration of cancer cells, including breast cancer, glioma and prostate cancer. We are using combined molecular and cell biology approaches to dissecting Slit-Robo signaling in neuronal guidance and tumor suppression. Our research has provided new insights into signal transduction pathways mediating Slit function. Enhancing or activating the endogenous mechanisms that restrict or suppress cancer invasion/metastasis will likely provide novel approaches to cancer metastasis.
For more information please view the faculty profile of Jane Wu, MD,PhD.
View a full list of publications by Jane Wu at PubMed
Jane Wu, MD, PhD, at 312-503-0684
Sidan Du, PhD
Research Assistant Professor
Kazuo Fushimi, PhD
Haipeng Cheng, PhD
Yang Li, PhD
Guodong Liu, PhD
Jun Shi, PhD
Warren McGee (MSTP)