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To facilitate the detection and management of potential clinical antiviral resistance, in vitro selection of drug-resistant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) against the virus Mpro inhibitor nirmatrelvir (Paxlovid active component) was conducted. Six Mpro mutation patterns containing T304I alone or in combination with T21I, L50F, T135I, S144A, or A173V emerged, with A173V+T304I and T21I+S144A+T304I mutations showing >20-fold resistance each. Biochemical analyses indicated inhibition constant shifts aligned to antiviral results, with S144A and A173V each markedly reducing nirmatrelvir inhibition and Mpro activity. SARS-CoV-2 surveillance revealed that in vitro resistance-associated mutations from our studies and those reported in the literature were rarely detected in the Global Initiative on Sharing All Influenza Data database. In the Paxlovid Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients trial, E166V was the only emergent resistance mutation, observed in three Paxlovid-treated patients, none of whom experienced COVID-19-related hospitalization or death.
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Antivirais , Tratamento Farmacológico da COVID-19 , Farmacorresistência Viral , Mutação , SARS-CoV-2 , SARS-CoV-2/genética , SARS-CoV-2/efeitos dos fármacos , Farmacorresistência Viral/genética , Humanos , Antivirais/farmacologia , Antivirais/uso terapêutico , COVID-19/virologia , COVID-19/genética , COVID-19/epidemiologia , Proteases 3C de Coronavírus/genética , Proteases 3C de Coronavírus/antagonistas & inibidores , Lactamas , Leucina , Nitrilas , ProlinaRESUMO
Selective activation of the M4 muscarinic acetylcholine receptor subtype offers a novel strategy for the treatment of psychosis in multiple neurological disorders. Although the development of traditional muscarinic activators has been stymied due to pan-receptor activation, muscarinic receptor subtype selectivity can be achieved through the utilization of a subtype of a unique allosteric site. A major challenge in capitalizing on this allosteric site to date has been achieving a balance of suitable potency and brain penetration. Herein, we describe the design of a brain penetrant series of M4 selective positive allosteric modulators (PAMs), ultimately culminating in the identification of 21 (PF-06852231, now CVL-231/emraclidine), which is under active clinical development as a novel mechanism and approach for the treatment of schizophrenia.
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Encéfalo , Desenho de Fármacos , Receptor Muscarínico M4 , Receptor Muscarínico M4/metabolismo , Receptor Muscarínico M4/agonistas , Regulação Alostérica/efeitos dos fármacos , Humanos , Animais , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Relação Estrutura-Atividade , Ratos , Cricetulus , Células CHO , Agonistas Muscarínicos/farmacologia , Agonistas Muscarínicos/síntese química , Agonistas Muscarínicos/química , Esquizofrenia/tratamento farmacológico , Esquizofrenia/metabolismoRESUMO
Despite the record-breaking discovery, development and approval of vaccines and antiviral therapeutics such as Paxlovid, coronavirus disease 2019 (COVID-19) remained the fourth leading cause of death in the world and third highest in the United States in 2022. Here, we report the discovery and characterization of PF-07817883, a second-generation, orally bioavailable, SARS-CoV-2 main protease inhibitor with improved metabolic stability versus nirmatrelvir, the antiviral component of the ritonavir-boosted therapy Paxlovid. We demonstrate the in vitro pan-human coronavirus antiviral activity and off-target selectivity profile of PF-07817883. PF-07817883 also demonstrated oral efficacy in a mouse-adapted SARS-CoV-2 model at plasma concentrations equivalent to nirmatrelvir. The preclinical in vivo pharmacokinetics and metabolism studies in human matrices are suggestive of improved oral pharmacokinetics for PF-07817883 in humans, relative to nirmatrelvir. In vitro inhibition/induction studies against major human drug metabolizing enzymes/transporters suggest a low potential for perpetrator drug-drug interactions upon single-agent use of PF-07817883.
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Antivirais , Tratamento Farmacológico da COVID-19 , Inibidores de Proteases , SARS-CoV-2 , Humanos , Animais , Camundongos , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , Antivirais/farmacocinética , Antivirais/uso terapêutico , Antivirais/química , Administração Oral , Inibidores de Proteases/farmacologia , Inibidores de Proteases/farmacocinética , Inibidores de Proteases/uso terapêutico , Inibidores de Proteases/química , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/metabolismo , Ratos , COVID-19/virologiaRESUMO
Glycerol-3-phosphate acyltransferase (GPAT)1 is a mitochondrial outer membrane protein that catalyzes the first step of de novo glycerolipid biosynthesis. Hepatic expression of GPAT1 is linked to liver fat accumulation and the severity of nonalcoholic fatty liver diseases. Here we present the cryo-EM structures of human GPAT1 in substrate analog-bound and product-bound states. The structures reveal an N-terminal acyltransferase domain that harbors important catalytic motifs and a tightly associated C-terminal domain that is critical for proper protein folding. Unexpectedly, GPAT1 has no transmembrane regions as previously proposed but instead associates with the membrane via an amphipathic surface patch and an N-terminal loop-helix region that contains a mitochondrial-targeting signal. Combined structural, computational and functional studies uncover a hydrophobic pathway within GPAT1 for lipid trafficking. The results presented herein lay a framework for rational inhibitor development for GPAT1.
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Fígado , Membranas Mitocondriais , Humanos , Fígado/metabolismo , Membranas Mitocondriais/metabolismo , Glicerol-3-Fosfato O-Aciltransferase/química , Glicerol-3-Fosfato O-Aciltransferase/metabolismo , Sequência de AminoácidosRESUMO
Vero cells are widely used for antiviral tests and virology research for SARS-CoV-2 as well as viruses from various other families. However, Vero cells generally express high levels of multi-drug resistance 1 (MDR1) or Pgp protein, the efflux transporter of foreign substances including many antiviral compounds, affecting the antiviral activity as well as interpretation of data. To address this, a Pgp gene knockout VeroE6 cell line (VeroE6-Pgp-KO) was generated using CRISPR-CAS9 technology. These cells no longer expressed the Pgp protein as indicated by flow cytometry analysis following staining with a Pgp-specific monoclonal antibody. They also showed significantly reduced efflux transporter activity in the calcein acetoxymethyl ester (calcein AM) assay. The VeroE6-Pgp-KO cells and the parental VeroE6 cells were each infected with SARS-CoV-2 to test antiviral activities of remdesivir and nirmatrelvir, two known Pgp substrates, in the presence or absence of a Pgp inhibitor. The compounds showed antiviral activities in VeroE6-Pgp-KO cells similar to that observed in the presence of the Pgp inhibitor. Thus, the newly established VeroE6-Pgp-KO cell line adds a new in vitro virus infection system for SARS-CoV-2 and possibly other viruses to test antiviral therapies without a need to control the Pgp activity. Removal of the Pgp inhibitor for antiviral assays will lead to less data variation and prevent failed assays.
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Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Humanos , Chlorocebus aethiops , Animais , SARS-CoV-2/genética , Antivirais/farmacologia , Técnicas de Inativação de Genes , Células Vero , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Linhagem CelularRESUMO
OBJECTIVE: Branched chain amino acid (BCAA) catabolic defects are implicated to be causal determinates of multiple diseases. This work aimed to better understand how enhancing BCAA catabolism affected metabolic homeostasis as well as the mechanisms underlying these improvements. METHODS: The rate limiting step of BCAA catabolism is the irreversible decarboxylation by the branched chain ketoacid dehydrogenase (BCKDH) enzyme complex, which is post-translationally controlled through phosphorylation by BCKDH kinase (BDK). This study utilized BT2, a small molecule allosteric inhibitor of BDK, in multiple mouse models of metabolic dysfunction and NAFLD including the high fat diet (HFD) model with acute and chronic treatment paradigms, the choline deficient and methionine minimal high fat diet (CDAHFD) model, and the low-density lipoprotein receptor null mouse model (Ldlr-/-). shRNA was additionally used to knock down BDK in liver to elucidate liver-specific effects of BDK inhibition in HFD-fed mice. RESULTS: A rapid improvement in insulin sensitivity was observed in HFD-fed and lean mice after BT2 treatment. Resistance to steatosis was assessed in HFD-fed mice, CDAHFD-fed mice, and Ldlr-/- mice. In all cases, BT2 treatment reduced steatosis and/or inflammation. Fasting and refeeding demonstrated a lack of response to feeding-induced changes in plasma metabolites including insulin and beta-hydroxybutyrate and hepatic gene changes in BT2-treated mice. Mechanistically, BT2 treatment acutely altered the expression of genes involved in fatty acid oxidation and lipogenesis in liver, and upstream regulator analysis suggested that BT2 treatment activated PPARα. However, BT2 did not directly activate PPARα in vitro. Conversely, shRNA-AAV-mediated knockdown of BDK specifically in liver in vivo did not demonstrate any effects on glycemia, steatosis, or PPARα-mediated gene expression in mice. CONCLUSIONS: These data suggest that BT2 treatment acutely improves metabolism and liver steatosis in multiple mouse models. While many molecular changes occur in liver in BT2-treated mice, these changes were not observed in mice with AAV-mediated shRNA knockdown of BDK. All together, these data suggest that systemic BDK inhibition is required to improve metabolism and steatosis by prolonging a fasting signature in a paracrine manner. Therefore, BCAA may act as a "fed signal" to promote nutrient storage and reduced systemic BCAA levels as shown in this study via BDK inhibition may act as a "fasting signal" to prolong the catabolic state.
Assuntos
Fígado Gorduroso , PPAR alfa , Animais , Camundongos , 3-Metil-2-Oxobutanoato Desidrogenase (Lipoamida)/metabolismo , Aminoácidos de Cadeia Ramificada/metabolismo , Jejum , Camundongos Knockout , RNA Interferente PequenoRESUMO
The COVID-19 pandemic continues to be a public health threat with emerging variants of SARS-CoV-2. Nirmatrelvir (PF-07321332) is a reversible, covalent inhibitor targeting the main protease (Mpro) of SARS-CoV-2 and the active protease inhibitor in PAXLOVID (nirmatrelvir tablets and ritonavir tablets). However, the efficacy of nirmatrelvir is underdetermined against evolving SARS-CoV-2 variants. Here, we evaluated the in vitro catalytic activity and potency of nirmatrelvir against the Mpro of prevalent variants of concern (VOCs) or variants of interest (VOIs): Alpha (α, B.1.1.7), Beta (ß, B.1.351), Delta (δ, B1.617.2), Gamma (γ, P.1), Lambda (λ, B.1.1.1.37/C37), Omicron (ο, B.1.1.529), as well as the original Washington or wildtype strain. These VOCs/VOIs carry prevalent mutations at varying frequencies in the Mpro specifically for α, ß, γ (K90R), λ (G15S), and ο (P132H). In vitro biochemical enzymatic assay characterization of the enzyme kinetics of the mutant Mpros demonstrates that they are catalytically comparable to wildtype. We found that nirmatrelvir has similar potency against each mutant Mpro including P132H that is observed in the Omicron variant with a Ki of 0.635 nM as compared to a Ki of 0.933 nM for wildtype. The molecular basis for these observations were provided by solution-phase structural dynamics and structural determination of nirmatrelvir bound to the ο, λ, and ß Mpro at 1.63 to 2.09 Å resolution. These in vitro data suggest that PAXLOVID has the potential to maintain plasma concentrations of nirmatrelvir many-fold times higher than the amount required to stop the SARS-CoV-2 VOC/VOI, including Omicron, from replicating in cells.
Assuntos
Tratamento Farmacológico da COVID-19 , COVID-19 , Lactamas/química , SARS-CoV-2 , Inibidores de Protease Viral/química , COVID-19/virologia , Proteases 3C de Coronavírus , Cisteína Endopeptidases/metabolismo , Humanos , Leucina , Nitrilas , Pandemias , Prolina , SARS-CoV-2/efeitos dos fármacos , Proteínas Virais/metabolismoRESUMO
CD33/Siglec 3 is a myeloid lineage cell surface receptor that is known to regulate microglia activity. Multiple genome-wide association studies (GWAS) have identified genetic variants in the CD33 gene that convey protection from late-onset Alzheimer's disease. Furthermore, mechanistic studies into GWAS-linked variants suggest that disease protection is attributed to the alternative splicing of exon 2 of the CD33 pre-mRNA. Using a phenomimetic screen, a series of compounds were found to enhance the exclusion of CD33 exon 2, acting as a chemomimetic of the GWAS-linked gene variants. Additional studies confirmed that meyloid lineage cells treated with several of these compounds have a reduced full-length V-domain containing CD33 protein, while targeted RNA-seq concordantly demonstrated that compound 1 increases exon 2 skipping in cellular mRNA pools. These studies demonstrate how pharmacological interventions can be used to manipulate disease-relevant pre-mRNA splicing and provide a starting point for future efforts to identify small molecules that alter neuroimmune function that is rooted in the human biology of neurodegenerative disease.
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The worldwide outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. Alongside vaccines, antiviral therapeutics are an important part of the healthcare response to countering the ongoing threat presented by COVID-19. Here, we report the discovery and characterization of PF-07321332, an orally bioavailable SARS-CoV-2 main protease inhibitor with in vitro pan-human coronavirus antiviral activity and excellent off-target selectivity and in vivo safety profiles. PF-07321332 has demonstrated oral activity in a mouse-adapted SARS-CoV-2 model and has achieved oral plasma concentrations exceeding the in vitro antiviral cell potency in a phase 1 clinical trial in healthy human participants.
Assuntos
Tratamento Farmacológico da COVID-19 , Lactamas/farmacologia , Lactamas/uso terapêutico , Leucina/farmacologia , Leucina/uso terapêutico , Nitrilas/farmacologia , Nitrilas/uso terapêutico , Prolina/farmacologia , Prolina/uso terapêutico , SARS-CoV-2/efeitos dos fármacos , Inibidores de Protease Viral/farmacologia , Inibidores de Protease Viral/uso terapêutico , Administração Oral , Animais , COVID-19/virologia , Ensaios Clínicos Fase I como Assunto , Coronavirus/efeitos dos fármacos , Modelos Animais de Doenças , Quimioterapia Combinada , Humanos , Lactamas/administração & dosagem , Lactamas/farmacocinética , Leucina/administração & dosagem , Leucina/farmacocinética , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Nitrilas/administração & dosagem , Nitrilas/farmacocinética , Prolina/administração & dosagem , Prolina/farmacocinética , Ensaios Clínicos Controlados Aleatórios como Assunto , Ritonavir/administração & dosagem , Ritonavir/uso terapêutico , SARS-CoV-2/fisiologia , Inibidores de Protease Viral/administração & dosagem , Inibidores de Protease Viral/farmacocinética , Replicação Viral/efeitos dos fármacosRESUMO
COVID-19 caused by the SARS-CoV-2 virus has become a global pandemic. 3CL protease is a virally encoded protein that is essential across a broad spectrum of coronaviruses with no close human analogs. PF-00835231, a 3CL protease inhibitor, has exhibited potent in vitro antiviral activity against SARS-CoV-2 as a single agent. Here we report, the design and characterization of a phosphate prodrug PF-07304814 to enable the delivery and projected sustained systemic exposure in human of PF-00835231 to inhibit coronavirus family 3CL protease activity with selectivity over human host protease targets. Furthermore, we show that PF-00835231 has additive/synergistic activity in combination with remdesivir. We present the ADME, safety, in vitro, and in vivo antiviral activity data that supports the clinical evaluation of PF-07304814 as a potential COVID-19 treatment.
Assuntos
Tratamento Farmacológico da COVID-19 , Proteases 3C de Coronavírus/antagonistas & inibidores , Inibidores de Protease de Coronavírus/administração & dosagem , Indóis/administração & dosagem , Leucina/administração & dosagem , Pirrolidinonas/administração & dosagem , Monofosfato de Adenosina/administração & dosagem , Monofosfato de Adenosina/efeitos adversos , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/farmacocinética , Alanina/administração & dosagem , Alanina/efeitos adversos , Alanina/análogos & derivados , Alanina/farmacocinética , Animais , COVID-19/virologia , Chlorocebus aethiops , Coronavirus Humano 229E/efeitos dos fármacos , Coronavirus Humano 229E/enzimologia , Inibidores de Protease de Coronavírus/efeitos adversos , Inibidores de Protease de Coronavírus/farmacocinética , Modelos Animais de Doenças , Desenho de Fármacos , Sinergismo Farmacológico , Quimioterapia Combinada , Células HeLa , Humanos , Indóis/efeitos adversos , Indóis/farmacocinética , Infusões Intravenosas , Leucina/efeitos adversos , Leucina/farmacocinética , Camundongos , Pirrolidinonas/efeitos adversos , Pirrolidinonas/farmacocinética , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/efeitos dos fármacos , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/enzimologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/enzimologia , Células VeroRESUMO
The solute carrier (SLC) superfamily represents the biggest family of transporters with important roles in health and disease. Despite being attractive and druggable targets, the majority of SLCs remains understudied. One major hurdle in research on SLCs is the lack of tools, such as cell-based assays to investigate their biological role and for drug discovery. Another challenge is the disperse and anecdotal information on assay strategies that are suitable for SLCs. This review provides a comprehensive overview of state-of-the-art cellular assay technologies for SLC research and discusses relevant SLC characteristics enabling the choice of an optimal assay technology. The Innovative Medicines Initiative consortium RESOLUTE intends to accelerate research on SLCs by providing the scientific community with high-quality reagents, assay technologies and data sets, and to ultimately unlock SLCs for drug discovery.
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We describe a mass spectrometry (MS) analytical platform resulting from the novel integration of acoustic droplet ejection (ADE) technology, an open-port interface (OPI), and electrospray ionization (ESI)-MS that creates a transformative system enabling high-speed sampling and label-free analysis. The ADE technology delivers nanoliter droplets in a touchless manner with high speed, precision, and accuracy. Subsequent sample dilution within the OPI, in concert with the capabilities of modern ESI-MS, eliminates the laborious sample preparation and method development required in current approaches. This platform is applied to a variety of experiments, including high-throughput (HT) pharmacology screening, label-free in situ enzyme kinetics, in vitro absorption, distribution, metabolism, elimination, pharmacokinetic and biomarker analysis, and HT parallel medicinal chemistry.
Assuntos
Ensaios de Triagem em Larga Escala , Espectrometria de Massas por Ionização por Electrospray , AcústicaRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of Coronavirus Disease 2019 (COVID-19). There is a dire need for novel effective antivirals to treat COVID-19, as the only approved direct-acting antiviral to date is remdesivir, targeting the viral polymerase complex. A potential alternate target in the viral life cycle is the main SARS-CoV-2 protease 3CLpro (Mpro). The drug candidate PF-00835231 is the active compound of the first anti-3CLpro regimen in clinical trials. Here, we perform a comparative analysis of PF-00835231, the pre-clinical 3CLpro inhibitor GC-376, and the polymerase inhibitor remdesivir, in alveolar basal epithelial cells modified to express ACE2 (A549+ACE2 cells). We find PF-00835231 with at least similar or higher potency than remdesivir or GC-376. A time-of-drug-addition approach delineates the timing of early SARS-CoV-2 life cycle steps in A549+ACE2 cells and validates PF-00835231's early time of action. In a model of the human polarized airway epithelium, both PF-00835231 and remdesivir potently inhibit SARS-CoV-2 at low micromolar concentrations. Finally, we show that the efflux transporter P-glycoprotein, which was previously suggested to diminish PF-00835231's efficacy based on experiments in monkey kidney Vero E6 cells, does not negatively impact PF-00835231 efficacy in either A549+ACE2 cells or human polarized airway epithelial cultures. Thus, our study provides in vitro evidence for the potential of PF-00835231 as an effective SARS-CoV-2 antiviral and addresses concerns that emerged based on prior studies in non-human in vitro models.Importance:The arsenal of SARS-CoV-2 specific antiviral drugs is extremely limited. Only one direct-acting antiviral drug is currently approved, the viral polymerase inhibitor remdesivir, and it has limited efficacy. Thus, there is a substantial need to develop additional antiviral compounds with minimal side effects and alternate viral targets. One such alternate target is its main protease, 3CLpro (Mpro), an essential component of the SARS-CoV-2 life cycle processing the viral polyprotein into the components of the viral polymerase complex. In this study, we characterize a novel antiviral drug, PF-00835231, which is the active component of the first-in-class 3CLpro-targeting regimen in clinical trials. Using 3D in vitro models of the human airway epithelium, we demonstrate the antiviral potential of PF-00835231 for inhibition of SARS-CoV-2.
RESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of Coronavirus Disease 2019 (COVID-19). There is a dire need for novel effective antivirals to treat COVID-19, as the only approved direct-acting antiviral to date is remdesivir, targeting the viral polymerase complex. A potential alternate target in the viral life cycle is the main SARS-CoV-2 protease 3CLpro (Mpro). The drug candidate PF-00835231 is the active compound of the first anti-3CLpro regimen in clinical trials. Here, we perform a comparative analysis of PF-00835231, the pre-clinical 3CLpro inhibitor GC-376, and the polymerase inhibitor remdesivir, in alveolar basal epithelial cells modified to express ACE2 (A549+ACE2 cells). We find PF-00835231 with at least similar or higher potency than remdesivir or GC-376. A time-of-drug-addition approach delineates the timing of early SARS-CoV-2 life cycle steps in A549+ACE2 cells and validates PF-00835231's early time of action. In a model of the human polarized airway epithelium, both PF-00835231 and remdesivir potently inhibit SARS-CoV-2 at low micromolar concentrations. Finally, we show that the efflux transporter P-glycoprotein, which was previously suggested to diminish PF-00835231's efficacy based on experiments in monkey kidney Vero E6 cells, does not negatively impact PF-00835231 efficacy in either A549+ACE2 cells or human polarized airway epithelial cultures. Thus, our study provides in vitro evidence for the potential of PF-00835231 as an effective SARS-CoV-2 antiviral and addresses concerns that emerged based on prior studies in non-human in vitro models.
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Utilizing a phenotypic screen, we identified chemical matter that increased astrocytic apoE secretion in vitro. We designed a clickable photoaffinity probe based on a pyrrolidine lead compound and carried out probe-based quantitative chemical proteomics in human astrocytoma CCF-STTG1 cells to identify liver x receptor ß (LXRß) as the target. Binding of the small molecule ligand stabilized LXRß, as shown by cellular thermal shift assay (CETSA). In addition, we identified a probe-modified peptide by mass spectrometry and proposed a model where the photoaffinity probe is bound in the ligand-binding pocket of LXRß. Taken together, our findings demonstrated that the lead chemical matter bound directly to LXRß, and our results highlight the power of chemical proteomic approaches to identify the target of a phenotypic screening hit. Additionally, the LXR photoaffinity probe and lead compound described herein may serve as valuable tools to further evaluate the LXR pathway.
Assuntos
Apolipoproteínas E/metabolismo , Astrócitos/metabolismo , Receptores X do Fígado/metabolismo , Astrócitos/citologia , Linhagem Celular , Humanos , Ligantes , Ligação Proteica , ProteômicaRESUMO
COVID-19 caused by the SARS-CoV-2 virus has become a global pandemic. 3CL protease is a virally encoded protein that is essential across a broad spectrum of coronaviruses with no close human analogs. The designed phosphate prodrug PF-07304814 is metabolized to PF-00835321 which is a potent inhibitor in vitro of the coronavirus family 3CL pro, with selectivity over human host protease targets. Furthermore, PF-00835231 exhibits potent in vitro antiviral activity against SARS-CoV-2 as a single agent and it is additive/synergistic in combination with remdesivir. We present the ADME, safety, in vitro , and in vivo antiviral activity data that supports the clinical evaluation of this compound as a potential COVID-19 treatment.
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The novel coronavirus disease COVID-19 that emerged in 2019 is caused by the virus SARS CoV-2 and named for its close genetic similarity to SARS CoV-1 that caused severe acute respiratory syndrome (SARS) in 2002. Both SARS coronavirus genomes encode two overlapping large polyproteins, which are cleaved at specific sites by a 3C-like cysteine protease (3CLpro) in a post-translational processing step that is critical for coronavirus replication. The 3CLpro sequences for CoV-1 and CoV-2 viruses are 100% identical in the catalytic domain that carries out protein cleavage. A research effort that focused on the discovery of reversible and irreversible ketone-based inhibitors of SARS CoV-1 3CLpro employing ligand-protease structures solved by X-ray crystallography led to the identification of 3 and 4. Preclinical experiments reveal 4 (PF-00835231) as a potent inhibitor of CoV-2 3CLpro with suitable pharmaceutical properties to warrant further development as an intravenous treatment for COVID-19.
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Antivirais/farmacologia , Proteases 3C de Coronavírus/antagonistas & inibidores , Cetonas/farmacologia , Inibidores de Proteases/farmacologia , SARS-CoV-2/efeitos dos fármacos , Animais , Antivirais/síntese química , Antivirais/metabolismo , Domínio Catalítico , Chlorocebus aethiops , Proteases 3C de Coronavírus/química , Proteases 3C de Coronavírus/metabolismo , Cristalografia por Raios X , Humanos , Cetonas/síntese química , Cetonas/metabolismo , Inibidores de Proteases/síntese química , Inibidores de Proteases/metabolismo , Ligação Proteica , Células Vero , Tratamento Farmacológico da COVID-19RESUMO
The promise of phenotypic screening resides in its track record of novel biology and first-in-class therapies. However, challenges stemming from major differences between target-based and phenotypic screening do exist. These challenges prompted us to rethink the critical stage of hit triage and validation on the road to clinical candidates and novel drug targets. Whereas this process is usually straightforward for target screening hits, phenotypic screening hits act through a variety of mostly unknown mechanisms within a large and poorly understood biological space. Our analysis suggests successful hit triage and validation is enabled by three types of biological knowledge-known mechanisms, disease biology, and safety-while structure-based hit triage may be counterproductive.
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Triagem , Descoberta de Drogas , Humanos , FenótipoRESUMO
Approximately 95% of human genes are alternatively spliced, and aberrant splicing events can cause disease. One pre-mRNA that is alternatively spliced and linked to neurodegenerative diseases is tau (microtubule-associated protein tau), which can cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) and can contribute to Alzheimer's disease. Here, we describe the design of structure-specific lead small molecules that directly target tau pre-mRNA from sequence. This was followed by hit expansion and analogue synthesis to further improve upon these initial lead molecules. The emergent compounds were assessed for functional activity in a battery of assays, including binding assays and an assay that mimics molecular recognition of tau pre-mRNA by a U1 small nuclear ribonucleoprotein (snRNP) splicing factor. Compounds that emerged from these studies had enhanced potency and selectivity for the target RNA relative to the initial hits, while also having significantly improved drug-like properties. The compounds are shown to directly target tau pre-mRNA in cells, via chemical cross-linking and isolation by pull-down target profiling, and to rescue disease-relevant splicing of tau pre-mRNA in a variety of cellular systems, including primary neurons. More broadly, this study shows that lead, structure-specific compounds can be designed from sequence and then further optimized for their physicochemical properties while at the same time enhancing their activity.