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Science (New York, N.Y.) Feb 2019The gut microbiota is implicated in the metabolism of many medical drugs, with consequences for interpersonal variation in drug efficacy and toxicity. However,...
The gut microbiota is implicated in the metabolism of many medical drugs, with consequences for interpersonal variation in drug efficacy and toxicity. However, quantifying microbial contributions to drug metabolism is challenging, particularly in cases where host and microbiome perform the same metabolic transformation. We combined gut commensal genetics with gnotobiotics to measure brivudine drug metabolism across tissues in mice that vary in a single microbiome-encoded enzyme. Informed by these measurements, we built a pharmacokinetic model that quantitatively predicts microbiome contributions to systemic drug and metabolite exposure, as a function of bioavailability, host and microbial drug-metabolizing activity, drug and metabolite absorption, and intestinal transit kinetics. Clonazepam studies illustrate how this approach disentangles microbiome contributions to metabolism of drugs subject to multiple metabolic routes and transformations.
Topics: Animals; Bacteroides thetaiotaomicron; Biological Availability; Biotransformation; Bromodeoxyuridine; Clonazepam; Gastrointestinal Microbiome; Germ-Free Life; Mice
PubMed: 30733391
DOI: 10.1126/science.aat9931 -
Molecules (Basel, Switzerland) Feb 2021Nucleoside and nucleotide analogues are essential antivirals in the treatment of infectious diseases such as human immunodeficiency virus (HIV), hepatitis B virus (HBV),... (Review)
Review
Nucleoside and nucleotide analogues are essential antivirals in the treatment of infectious diseases such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus (HSV), varicella-zoster virus (VZV), and human cytomegalovirus (HCMV). To celebrate the 80th birthday of Prof. Dr. Erik De Clercq on 28 March 2021, this review provides an overview of his contributions to eight approved nucleos(t)ide drugs: (i) three adenosine nucleotide analogues, namely tenofovir disoproxil fumarate (Viread) and tenofovir alafenamide (Vemlidy) against HIV and HBV infections and adefovir dipivoxil (Hepsera) against HBV infections; (ii) two thymidine nucleoside analogues, namely brivudine (Zostex) against HSV-1 and VZV infections and stavudine (Zerit) against HIV infections; (iii) two guanosine analogues, namely valacyclovir (Valtrex, Zelitrex) against HSV and VZV and rabacfosadine (Tanovea-CA1) for the treatment of lymphoma in dogs; and (iv) one cytidine nucleotide analogue, namely cidofovir (Vistide) for the treatment of HCMV retinitis in AIDS patients. Although adefovir dipivoxil, stavudine, and cidofovir are virtually discontinued for clinical use, tenofovir disoproxil fumarate and tenofovir alafenamide remain the most important antivirals against HIV and HBV infections worldwide. Overall, the broad-spectrum antiviral potential of nucleos(t)ide analogues supports their development to treat or prevent current and emerging infectious diseases worldwide.
Topics: Anniversaries and Special Events; Antiviral Agents; Drug Discovery; History, 20th Century; History, 21st Century; Humans; Nucleosides; Nucleotides; Virus Diseases; Viruses
PubMed: 33572409
DOI: 10.3390/molecules26040923 -
Frontiers in Cellular Neuroscience 2021Neural progenitor cell (NPC) transplants are a promising therapy for treating spinal cord injury (SCI), however, their long-term role after engraftment and the relative...
Neural progenitor cell (NPC) transplants are a promising therapy for treating spinal cord injury (SCI), however, their long-term role after engraftment and the relative contribution to ongoing functional recovery remains a key knowledge gap. Selective human cell ablation techniques, currently being developed to improve the safety of progenitor cell transplant therapies in patients, may also be used as tools to probe the regenerative effects attributable to individual grafted cell populations. The Herpes Simplex Virus Thymidine Kinase (HSV-TK) and ganciclovir (GCV) system has been extensively studied in the context of SCI and broader CNS disease. However, the efficacy of brivudine (BVDU), another HSV-TK prodrug with potentially reduced bystander cytotoxic effects and toxicity, has yet to be investigated for NPC ablation. In this study, we demonstrate successful generation and ablation of HSV-TK-expressing human iPSC-derived NPCs with a >80% reduction in survival over controls. We validated an HSV-TK and GCV/BVDU synergistic system with iPSC-NPCs using an efficient gene-transfer method and ablation in a translationally relevant model of SCI. Our findings demonstrate enhanced ablation efficiency and reduced bystander effects when targeting all rapidly dividing cells with combinatorial GCV and BVDU treatment. However, for use in loss of function studies, BVDU alone is optimal due to reduced nonselective cell ablation.
PubMed: 34938162
DOI: 10.3389/fncel.2021.638021 -
PloS One 2015Varicella zoster virus (VZV) is a highly infectious human herpesvirus that is the causative agent for chicken pox and shingles. VZV encodes a functional thymidylate...
Structure of the Varicella Zoster Virus Thymidylate Synthase Establishes Functional and Structural Similarities as the Human Enzyme and Potentiates Itself as a Target of Brivudine.
Varicella zoster virus (VZV) is a highly infectious human herpesvirus that is the causative agent for chicken pox and shingles. VZV encodes a functional thymidylate synthase (TS), which is the sole enzyme that produces dTMP from dUMP de novo. To study substrate binding, the complex structure of TSVZV with dUMP was determined to a resolution of 2.9 Å. In the absence of a folate co-substrate, dUMP binds in the conserved TS active site and is coordinated similarly as in the human encoded TS (TSHS) in an open conformation. The interactions between TSVZV with dUMP and a cofactor analog, raltitrexed, were also studied using differential scanning fluorimetry (DSF), suggesting that TSVZV binds dUMP and raltitrexed in a sequential binding mode like other TS. The DSF also revealed interactions between TSVZV and in vitro phosphorylated brivudine (BVDUP), a highly potent anti-herpesvirus drug against VZV infections. The binding of BVDUP to TSVZV was further confirmed by the complex structure of TSVZV and BVDUP solved at a resolution of 2.9 Å. BVDUP binds similarly as dUMP in the TSHS but it induces a closed conformation of the active site. The structure supports that the 5-bromovinyl substituent on BVDUP is likely to inhibit TSVZV by preventing the transfer of a methylene group from its cofactor and the subsequent formation of dTMP. The interactions between TSVZV and BVDUP are consistent with that TSVZV is indeed a target of brivudine in vivo. The work also provided the structural basis for rational design of more specific TSVZV inhibitors.
Topics: Antiviral Agents; Apoenzymes; Binding Sites; Bromodeoxyuridine; Herpesvirus 3, Human; Humans; Models, Molecular; Phosphorylation; Protein Binding; Protein Conformation; Thymidylate Synthase
PubMed: 26630264
DOI: 10.1371/journal.pone.0143947 -
Anales Del Sistema Sanitario de Navarra Aug 2018
Topics: Aged; Antimetabolites, Antineoplastic; Antiviral Agents; Bromodeoxyuridine; Diagnostic Errors; Drug Interactions; Fatal Outcome; Fluorouracil; Herpes Zoster; Humans; Male
PubMed: 29943764
DOI: 10.23938/ASSN.0297 -
Acta Pharmaceutica Sinica. B Nov 2015
Review
PubMed: 26713268
DOI: 10.1016/j.apsb.2015.09.001 -
Neuro-ophthalmology (Aeolus Press) 2014A 49-year-old woman who complained of lacrimation, foreign body sensation, and eyelid oedema presented to our outpatient clinic. External examination identified...
A 49-year-old woman who complained of lacrimation, foreign body sensation, and eyelid oedema presented to our outpatient clinic. External examination identified erythematous rash with vesicles on the left eyelid, dorsum of the nose, and forehead of the patient. She was diagnosed to have herpes zoster ophthalmicus (HZO), and was started on oral brivudine and topical acyclovir. On the third day of the treatment, visual acuity of left eye was reduced; left blepharoptosis and total ophthalmoplegia had developed. Orbital magnetic resonance imaging (MRI) showed enlargement of the extraocular muscles, and perineural enhancement of the optic nerve on that side. Oral brivudine was replaced with intravenous acyclovir, and oral corticosteroid was initiated. Complete resolution of proptosis and restriction of eye movements were achieved, and significant improvement of visual acuity was observed within a week. Orbital apex syndrome, a severe and rare complication of herpes zoster infection, can develop despite antiviral treatment. Rapid institution of appropriate therapy may provide complete recovery.
PubMed: 27928310
DOI: 10.3109/01658107.2014.923914 -
Journal of Virology Jul 2020Herpes simplex virus 1 (HSV-1) can induce damage in brain regions that include the hippocampus and associated limbic structures. These neurogenic niches are important...
Herpes simplex virus 1 (HSV-1) can induce damage in brain regions that include the hippocampus and associated limbic structures. These neurogenic niches are important because they are associated with memory formation and are highly enriched with neural progenitor cells (NPCs). The susceptibility and fate of HSV-1-infected NPCs are largely unexplored. We differentiated human induced pluripotent stem cells (hiPSCs) into NPCs to generate two-dimensional (2D) and three-dimensional (3D) culture models to examine the interaction of HSV-1 with NPCs. Here, we show that (i) NPCs can be efficiently infected by HSV-1, but infection does not result in cell death of most NPCs, even at high multiplicities of infection (MOIs); (ii) limited HSV-1 replication and gene expression can be detected in the infected NPCs; (iii) a viral silencing mechanism is established in NPCs exposed to the antivirals (E)-5-(2-bromovinyl)-2'-deoxyuridine (5BVdU) and alpha interferon (IFN-α) and when the antivirals are removed, spontaneous reactivation can occur at low frequency; (iv) HSV-1 impairs the ability of NPCs to migrate in a dose-dependent fashion in the presence of 5BVdU plus IFN-α; and (v) 3D cultures of NPCs are less susceptible to HSV-1 infection than 2D cultures. These results suggest that NPC pools could be sites of HSV-1 reactivation in the central nervous system (CNS). Finally, our results highlight the potential value of hiPSC-derived 3D cultures to model HSV-1-NPC interaction. This study employed human induced pluripotent stem cells (hiPSCs) to model the interaction of HSV-1 with NPCs, which reside in the neurogenic niches of the CNS and play a fundamental role in adult neurogenesis. Herein, we provide evidence that in NPCs infected at an MOI as low as 0.001, HSV-1 can establish a latent state, suggesting that (i) a variant of classical HSV-1 latency can be established during earlier stages of neuronal differentiation and (ii) neurogenic niches in the brain may constitute additional sites of viral reactivation. Lytic HSV-1 infections impaired NPC migration, which represents a critical step in neurogenesis. A difference in susceptibility to HSV-1 infection between two-dimensional (2D) and three-dimensional (3D) NPC cultures was observed, highlighting the potential value of 3D cultures for modeling host-pathogen interactions. Together, our results are relevant in light of observations relating HSV-1 infection to postencephalitic cognitive dysfunction.
Topics: Animals; Central Nervous System; Chlorocebus aethiops; Herpes Simplex; Herpesvirus 1, Human; Host-Pathogen Interactions; Humans; Induced Pluripotent Stem Cells; Neural Stem Cells; Neurogenesis; Vero Cells; Virus Latency; Virus Replication
PubMed: 32493817
DOI: 10.1128/JVI.00994-20 -
Bioorganic & Medicinal Chemistry Letters Dec 2016Nucleosides represent a major chemotherapeutic class for treating cancer, however their limitations in terms of cellular uptake, nucleoside kinase-mediated activation...
Nucleosides represent a major chemotherapeutic class for treating cancer, however their limitations in terms of cellular uptake, nucleoside kinase-mediated activation and catabolism are well-documented. The monophosphate pro-nucleotides known as ProTides represents a powerful strategy for bypassing the dependence on active transport and nucleoside kinase-mediated activation. Herein, we report the structural tuning of BVdU ProTides. Forty six phosphoramidates were prepared and biologically evaluated against three different cancer cell lines; murine leukemia (L1210), human CD T-lymphocyte (CEM) and human cervical carcinoma (HeLa). Twenty-fold potency enhancement compared to BVdU was achieved against L1210 cells. Interestingly, a number of ProTides showed low micromolar activity against CEM and HeLa cells compared to the inactive parent BVdU. The ProTides showed poor, if any measurable toxicity to non-tumourigenic human lung fibroblast cell cultures. Separation of four pairs of the diastereoisomeric mixtures and comparison of their spectral properties, biological activities and enzymatic activation rate is reported.
Topics: Amides; Animals; Antineoplastic Agents; Antiviral Agents; Bromodeoxyuridine; Cell Line, Tumor; Cell Proliferation; Humans; Mice; Neoplasms; Phosphoric Acids
PubMed: 27818111
DOI: 10.1016/j.bmcl.2016.10.077 -
Viruses Apr 2022There is a continued need to understand varicella-zoster virus (VZV) pathogenesis and to develop more effective antivirals, as it causes chickenpox and zoster. As a...
Development of Robust Varicella Zoster Virus Luciferase Reporter Viruses for In Vivo Monitoring of Virus Growth and Its Antiviral Inhibition in Culture, Skin, and Humanized Mice.
There is a continued need to understand varicella-zoster virus (VZV) pathogenesis and to develop more effective antivirals, as it causes chickenpox and zoster. As a human-restricted alphaherpesvirus, the use of human skin in culture and mice is critical in order to reveal the important VZV genes that are required for pathogenesis but that are not necessarily observed in the cell culture. We previously used VZV-expressing firefly luciferase (fLuc), under the control of the constitutively active SV40 promoter (VZV-BAC-Luc), to measure the VZV spread in the same sample. However, the fLuc expression was independent of viral gene expression and viral DNA replication programs. Here, we developed robust reporter VZV viruses by using bacterial artificial chromosome (BAC) technology, expressing luciferase from VZV-specific promoters. We also identified two spurious mutations in VZV-BAC that were corrected for maximum pathogenesis. VZV with fLuc driven by ORF57 showed superior growth in cells, human skin explants, and skin xenografts in mice. The ORF57-driven luciferase activity had a short half-life in the presence of foscarnet. This background was then used to investigate the roles for ORF36 (thymidine kinase (TK)) and ORF13 (thymidylate synthase (TS)) in skin. The studies reveal that VZV-∆TS had increased sensitivity to brivudine and was highly impaired for skin replication. This is the first report of a phenotype that is associated with the loss of TS.
Topics: Animals; Antiviral Agents; Chickenpox; DNA Replication; DNA, Viral; Genes, Reporter; Herpes Zoster; Herpesvirus 3, Human; Humans; Luciferases; Mice; Mice, SCID; Skin; Viral Regulatory and Accessory Proteins; Virus Replication
PubMed: 35458556
DOI: 10.3390/v14040826