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1.
Sci Rep ; 11(1): 24442, 2021 12 24.
Article in English | MEDLINE | ID: covidwho-1577650

ABSTRACT

Therapeutic interventions targeting viral infections remain a significant challenge for both the medical and scientific communities. While specific antiviral agents have shown success as therapeutics, viral resistance inevitably develops, making many of these approaches ineffective. This inescapable obstacle warrants alternative approaches, such as the targeting of host cellular factors. Respiratory syncytial virus (RSV), the major respiratory pathogen of infants and children worldwide, causes respiratory tract infection ranging from mild upper respiratory tract symptoms to severe life-threatening lower respiratory tract disease. Despite the fact that the molecular biology of the virus, which was originally discovered in 1956, is well described, there is no vaccine or effective antiviral treatment against RSV infection. Here, we demonstrate that targeting host factors, specifically, mTOR signaling, reduces RSV protein production and generation of infectious progeny virus. Further, we show that this approach can be generalizable as inhibition of mTOR kinases reduces coronavirus gene expression, mRNA transcription and protein production. Overall, defining virus replication-dependent host functions may be an effective means to combat viral infections, particularly in the absence of antiviral drugs.


Subject(s)
Coronavirus/metabolism , Respiratory Syncytial Virus, Human/metabolism , TOR Serine-Threonine Kinases/metabolism , Viral Proteins/metabolism , A549 Cells , Coronavirus/drug effects , Coronavirus/genetics , Gene Expression Regulation, Viral/drug effects , Humans , Protein Biosynthesis/drug effects , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , RNA Interference , RNA, Small Interfering/metabolism , Rapamycin-Insensitive Companion of mTOR Protein/antagonists & inhibitors , Rapamycin-Insensitive Companion of mTOR Protein/genetics , Rapamycin-Insensitive Companion of mTOR Protein/metabolism , Regulatory-Associated Protein of mTOR/antagonists & inhibitors , Regulatory-Associated Protein of mTOR/genetics , Regulatory-Associated Protein of mTOR/metabolism , Respiratory Syncytial Virus Infections/drug therapy , Respiratory Syncytial Virus Infections/pathology , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus, Human/drug effects , Respiratory Syncytial Virus, Human/isolation & purification , TOR Serine-Threonine Kinases/antagonists & inhibitors , TOR Serine-Threonine Kinases/genetics , Viral Proteins/genetics
2.
Nat Commun ; 12(1): 652, 2021 01 28.
Article in English | MEDLINE | ID: covidwho-1397868

ABSTRACT

Injury and loss of oligodendrocytes can cause demyelinating diseases such as multiple sclerosis. To improve our understanding of human oligodendrocyte development, which could facilitate development of remyelination-based treatment strategies, here we describe time-course single-cell-transcriptomic analysis of developing human stem cell-derived oligodendrocyte-lineage-cells (hOLLCs). The study includes hOLLCs derived from both genome engineered embryonic stem cell (ESC) reporter cells containing an Identification-and-Purification tag driven by the endogenous PDGFRα promoter and from unmodified induced pluripotent (iPS) cells. Our analysis uncovers substantial transcriptional heterogeneity of PDGFRα-lineage hOLLCs. We discover sub-populations of human oligodendrocyte progenitor cells (hOPCs) including a potential cytokine-responsive hOPC subset, and identify candidate regulatory genes/networks that define the identity of these sub-populations. Pseudotime trajectory analysis defines developmental pathways of oligodendrocytes vs astrocytes from PDGFRα-expressing hOPCs and predicts differentially expressed genes between the two lineages. In addition, pathway enrichment analysis followed by pharmacological intervention of these pathways confirm that mTOR and cholesterol biosynthesis signaling pathways are involved in maturation of oligodendrocytes from hOPCs.


Subject(s)
Genetic Heterogeneity , Genetic Variation , Induced Pluripotent Stem Cells/metabolism , Oligodendrocyte Precursor Cells/metabolism , Single-Cell Analysis/methods , Transcriptome/genetics , Astrocytes/cytology , Astrocytes/metabolism , Cell Differentiation/genetics , Cell Line , Cell Lineage/genetics , Cholesterol/biosynthesis , Embryonic Stem Cells/cytology , Embryonic Stem Cells/metabolism , Gene Regulatory Networks/genetics , Humans , Induced Pluripotent Stem Cells/cytology , Oligodendrocyte Precursor Cells/cytology , Receptor, Platelet-Derived Growth Factor alpha/genetics , Receptor, Platelet-Derived Growth Factor alpha/metabolism , Signal Transduction/genetics , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism
3.
RNA ; 27(9): 1025-1045, 2021 09.
Article in English | MEDLINE | ID: covidwho-1269913

ABSTRACT

Viruses rely on the host translation machinery to synthesize their own proteins. Consequently, they have evolved varied mechanisms to co-opt host translation for their survival. SARS-CoV-2 relies on a nonstructural protein, Nsp1, for shutting down host translation. However, it is currently unknown how viral proteins and host factors critical for viral replication can escape a global shutdown of host translation. Here, using a novel FACS-based assay called MeTAFlow, we report a dose-dependent reduction in both nascent protein synthesis and mRNA abundance in cells expressing Nsp1. We perform RNA-seq and matched ribosome profiling experiments to identify gene-specific changes both at the mRNA expression and translation levels. We discover that a functionally coherent subset of human genes is preferentially translated in the context of Nsp1 expression. These genes include the translation machinery components, RNA binding proteins, and others important for viral pathogenicity. Importantly, we uncovered a remarkable enrichment of 5' terminal oligo-pyrimidine (TOP) tracts among preferentially translated genes. Using reporter assays, we validated that 5' UTRs from TOP transcripts can drive preferential expression in the presence of Nsp1. Finally, we found that LARP1, a key effector protein in the mTOR pathway, may contribute to preferential translation of TOP transcripts in response to Nsp1 expression. Collectively, our study suggests fine-tuning of host gene expression and translation by Nsp1 despite its global repressive effect on host protein synthesis.


Subject(s)
Host-Pathogen Interactions/genetics , Protein Biosynthesis , Proteins/chemistry , Proteins/genetics , Viral Nonstructural Proteins/genetics , 5' Untranslated Regions , Autoantigens/genetics , Autoantigens/metabolism , Gene Expression Regulation , HEK293 Cells , Humans , Protein Folding , Pyrimidines , RNA, Messenger/genetics , Ribonucleoproteins/genetics , Ribonucleoproteins/metabolism , Ribosomes/genetics , Ribosomes/virology , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , Viral Nonstructural Proteins/metabolism
4.
Mol Cell ; 81(13): 2838-2850.e6, 2021 07 01.
Article in English | MEDLINE | ID: covidwho-1202181

ABSTRACT

SARS-CoV-2 is an RNA virus whose success as a pathogen relies on its abilities to repurpose host RNA-binding proteins (RBPs) and to evade antiviral RBPs. To uncover the SARS-CoV-2 RNA interactome, we here develop a robust ribonucleoprotein (RNP) capture protocol and identify 109 host factors that directly bind to SARS-CoV-2 RNAs. Applying RNP capture on another coronavirus, HCoV-OC43, revealed evolutionarily conserved interactions between coronaviral RNAs and host proteins. Transcriptome analyses and knockdown experiments delineated 17 antiviral RBPs, including ZC3HAV1, TRIM25, PARP12, and SHFL, and 8 proviral RBPs, such as EIF3D and CSDE1, which are responsible for co-opting multiple steps of the mRNA life cycle. This also led to the identification of LARP1, a downstream target of the mTOR signaling pathway, as an antiviral host factor that interacts with the SARS-CoV-2 RNAs. Overall, this study provides a comprehensive list of RBPs regulating coronaviral replication and opens new avenues for therapeutic interventions.


Subject(s)
Autoantigens/genetics , COVID-19/genetics , RNA, Viral/genetics , Ribonucleoproteins/genetics , SARS-CoV-2/genetics , COVID-19/virology , Coronavirus OC43, Human/genetics , Coronavirus OC43, Human/pathogenicity , HEK293 Cells , Host-Pathogen Interactions/genetics , Humans , Protein Binding/genetics , Protein Interaction Maps/genetics , RNA-Binding Proteins/genetics , SARS-CoV-2/pathogenicity , TOR Serine-Threonine Kinases/genetics , Transcription Factors/genetics , Transcriptome/genetics , Tripartite Motif Proteins/genetics , Ubiquitin-Protein Ligases/genetics , Virus Replication/genetics
5.
Cells ; 9(9)2020 09 16.
Article in English | MEDLINE | ID: covidwho-1148288

ABSTRACT

Vaccine design traditionally focuses on inducing adaptive immune responses against a sole target pathogen. Considering that many microbes evade innate immune mechanisms to initiate infection, and in light of the discovery of epigenetically mediated innate immune training, the paradigm of vaccine design has the potential to change. The Bacillus Calmette-Guérin (BCG) vaccine induces some level of protection against Mycobacterium tuberculosis (Mtb) while stimulating trained immunity that correlates with lower mortality and increased protection against unrelated pathogens. This review will explore BCG-induced trained immunity, including the required pathways to establish this phenotype. Additionally, potential methods to improve or expand BCG trained immunity effects through alternative vaccine delivery and formulation methods will be discussed. Finally, advances in new anti-Mtb vaccines, other antimicrobial uses for BCG, and "innate memory-based vaccines" will be examined.


Subject(s)
Adaptive Immunity/drug effects , BCG Vaccine/administration & dosage , COVID-19/prevention & control , Epigenesis, Genetic/drug effects , Myeloid Cells/drug effects , SARS-CoV-2/pathogenicity , Tuberculosis, Pulmonary/prevention & control , Acetylmuramyl-Alanyl-Isoglutamine/immunology , Acetylmuramyl-Alanyl-Isoglutamine/metabolism , COVID-19/immunology , COVID-19/virology , Cross Protection , Epigenesis, Genetic/immunology , Histones/genetics , Histones/immunology , Humans , Mycobacterium tuberculosis , Myeloid Cells/immunology , Myeloid Cells/pathology , Nod2 Signaling Adaptor Protein/genetics , Nod2 Signaling Adaptor Protein/immunology , Pathogen-Associated Molecular Pattern Molecules/immunology , Pathogen-Associated Molecular Pattern Molecules/metabolism , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/immunology , Signal Transduction , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/immunology , Tuberculosis, Pulmonary/immunology , Tuberculosis, Pulmonary/microbiology
6.
Curr Neurovasc Res ; 17(5): 765-783, 2020.
Article in English | MEDLINE | ID: covidwho-922756

ABSTRACT

Metabolic disorders that include diabetes mellitus present significant challenges for maintaining the welfare of the global population. Metabolic diseases impact all systems of the body and despite current therapies that offer some protection through tight serum glucose control, ultimately such treatments cannot block the progression of disability and death realized with metabolic disorders. As a result, novel therapeutic avenues are critical for further development to address these concerns. An innovative strategy involves the vitamin nicotinamide and the pathways associated with the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), the mechanistic target of rapamycin (mTOR), mTOR Complex 1 (mTORC1), mTOR Complex 2 (mTORC2), AMP activated protein kinase (AMPK), and clock genes. Nicotinamide maintains an intimate relationship with these pathways to oversee metabolic disease and improve glucose utilization, limit mitochondrial dysfunction, block oxidative stress, potentially function as antiviral therapy, and foster cellular survival through mechanisms involving autophagy. However, the pathways of nicotinamide, SIRT1, mTOR, AMPK, and clock genes are complex and involve feedback pathways as well as trophic factors such as erythropoietin that require a careful balance to ensure metabolic homeostasis. Future work is warranted to gain additional insight into these vital pathways that can oversee both normal metabolic physiology and metabolic disease.


Subject(s)
Circadian Clocks/genetics , Metabolic Diseases/genetics , Niacinamide/genetics , Sirtuin 1/genetics , TOR Serine-Threonine Kinases/genetics , Animals , Humans , Metabolic Diseases/diagnosis , Metabolic Diseases/metabolism , Niacinamide/metabolism , Sirtuin 1/metabolism , TOR Serine-Threonine Kinases/metabolism
7.
Vet Microbiol ; 244: 108684, 2020 May.
Article in English | MEDLINE | ID: covidwho-827805

ABSTRACT

Porcine epidemic diarrhea virus (PEDV) has caused, and continues to cause, severe economic losses to the swine industry worldwide. The pathogenic mechanism and immune regulatory interactions between PEDV and the host remain largely unknown. In this study, the interaction between autophagy and PEDV replication in intestinal porcine epithelial (IPEC-J2) cells was investigated. The effects of the structural and nonstructural proteins of PEDV on the autophagy process and the autophagy-related signaling pathways were also examined. The results shown that PEDV replication increased the autophagy flux in IPEC-J2 cells, and that autophagy was beneficial to PEDV replication, which may be one of the reasons for the rapid damage to intestinal epithelial cells and the enhanced virulence of PEDV in both newborn piglets and finishing pigs. When autophagy was pharmacologically induced by rapamycin, PEDV replication increased from 8.5 × 105 TCID50/mL to 8.8 × 106 TCID50/mL in IPEC-J2 cells. When autophagy was pharmacologically suppressed by hydroxychloroquine, PEDV replication decreased from 8.5 × 105 TCID50/mL to 7.9 × 104 TCID50/mL. To identify which PEDV proteins were the key inducers of autophagy, all 4 structural proteins and 17 nonstructural proteins of PEDV were eukaryotic expressed. It was found that the nonstructural protein 6 (nsp6) and ORF3 of PEDV were able to induce significant autophagy in IPEC-J2 cells, but the other proteins were unable to induce autophagy. It was indicated that nsp6-induced autophagy mainly occurred via the PI3K/Akt/mTOR signaling pathway. The results accelerate the understanding of the biology and pathogenesis of PEDV infection and provide new insights into the development of effective therapeutic strategies.


Subject(s)
Autophagy , Porcine epidemic diarrhea virus/pathogenicity , Signal Transduction , Viral Nonstructural Proteins/genetics , Virus Replication , Animals , Cell Line , Epithelial Cells/pathology , Epithelial Cells/virology , Host-Pathogen Interactions , Intestines/cytology , Intestines/virology , Oncogene Protein v-akt/genetics , Oncogene Protein v-akt/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Porcine epidemic diarrhea virus/physiology , Swine , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , Viral Nonstructural Proteins/metabolism
8.
Proc Natl Acad Sci U S A ; 117(29): 17195-17203, 2020 07 21.
Article in English | MEDLINE | ID: covidwho-624792

ABSTRACT

The vast majority of intracellular protein targets are refractory toward small-molecule therapeutic engagement, and additional therapeutic modalities are needed to overcome this deficiency. Here, the identification and characterization of a natural product, WDB002, reveals a therapeutic modality that dramatically expands the currently accepted limits of druggability. WDB002, in complex with the FK506-binding protein (FKBP12), potently and selectively binds the human centrosomal protein 250 (CEP250), resulting in disruption of CEP250 function in cells. The recognition mode is unprecedented in that the targeted domain of CEP250 is a coiled coil and is topologically featureless, embodying both a structural motif and surface topology previously considered on the extreme limits of "undruggability" for an intracellular target. Structural studies reveal extensive protein-WDB002 and protein-protein contacts, with the latter being distinct from those seen in FKBP12 ternary complexes formed by FK506 and rapamycin. Outward-facing structural changes in a bound small molecule can thus reprogram FKBP12 to engage diverse, otherwise "undruggable" targets. The flat-targeting modality demonstrated here has the potential to expand the druggable target range of small-molecule therapeutics. As CEP250 was recently found to be an interaction partner with the Nsp13 protein of the SARS-CoV-2 virus that causes COVID-19 disease, it is possible that WDB002 or an analog may exert useful antiviral activity through its ability to form high-affinity ternary complexes containing CEP250 and FKBP12.


Subject(s)
Actinobacteria/genetics , Antiviral Agents/pharmacology , Genome, Bacterial , Macrolides/pharmacology , Protein Interaction Domains and Motifs/drug effects , Small Molecule Libraries/pharmacology , Tacrolimus Binding Protein 1A/chemistry , Tacrolimus Binding Protein 1A/metabolism , Actinobacteria/metabolism , Amino Acid Sequence , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Autoantigens/genetics , Autoantigens/metabolism , Calcineurin/genetics , Calcineurin/metabolism , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Evolution, Molecular , HEK293 Cells , Humans , Macrolides/chemistry , Macrolides/metabolism , Models, Molecular , Protein Conformation , Sequence Homology , Sirolimus/chemistry , Sirolimus/metabolism , Small Molecule Libraries/chemistry , Small Molecule Libraries/metabolism , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism
9.
Emerg Microbes Infect ; 9(1): 1748-1760, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-658315

ABSTRACT

How severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections engage cellular host pathways and innate immunity in infected cells remains largely elusive. We performed an integrative proteo-transcriptomics analysis in SARS-CoV-2 infected Huh7 cells to map the cellular response to the invading virus over time. We identified four pathways, ErbB, HIF-1, mTOR and TNF signaling, among others that were markedly modulated during the course of the SARS-CoV-2 infection in vitro. Western blot validation of the downstream effector molecules of these pathways revealed a dose-dependent activation of Akt, mTOR, S6K1 and 4E-BP1 at 24 hours post infection (hpi). However, we found a significant inhibition of HIF-1α through 24hpi and 48hpi of the infection, suggesting a crosstalk between the SARS-CoV-2 and the Akt/mTOR/HIF-1 signaling pathways. Inhibition of the mTOR signaling pathway using Akt inhibitor MK-2206 showed a significant reduction in virus production. Further investigations are required to better understand the molecular sequelae in order to guide potential therapy in the management of severe coronavirus disease 2019 (COVID-19) patients.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Gene Expression Profiling/methods , Pneumonia, Viral/virology , Proteomics/methods , Signal Transduction , COVID-19 , Cell Line , Chromatography, Liquid , Coronavirus Infections/genetics , Coronavirus Infections/metabolism , Gene Expression Regulation , High-Throughput Nucleotide Sequencing , Humans , Hypoxia-Inducible Factor 1/genetics , Hypoxia-Inducible Factor 1/metabolism , Pandemics , Pneumonia, Viral/genetics , Pneumonia, Viral/metabolism , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , SARS-CoV-2 , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , Tandem Mass Spectrometry
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