RESUMEN
Achieving pharmacological control over cardiomyocyte proliferation represents a prime goal in therapeutic cardiovascular research. Here, we identify a novel chemical tool compound for the expansion of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes. The forkhead box O (FOXO) inhibitor AS1842856 was identified as a significant hit from an unbiased proliferation screen in early, immature hiPSC- cardiomyocytes (eCMs). The mitogenic effects of AS1842856 turned out to be robust, dose-dependent, sustained, and reversible. eCM numbers increased >30-fold as induced by AS1842856 over three passages. Phenotypically as well as by marker gene expression, the compound interestingly appeared to counteract cellular maturation both in immature hiPSC-CMs as well as in more advanced ones. Thus, FOXO inhibitor AS1842856 presents a novel proliferation inducer for the chemically defined, xeno-free expansion of hiPSC-derived CMs, while its de-differentiation effect might as well bear potential in regenerative medicine.
Asunto(s)
Células Madre Pluripotentes Inducidas , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Matriz Extracelular , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Miocitos CardíacosRESUMEN
"Hot loop" protein segments have variable structure and conformation and contribute crucially to protein-protein interactions. We describe a new hot loop mimicking modality, termed PepNats, in which natural product (NP)-inspired structures are incorporated as conformation-determining and -restricting structural elements into macrocyclic hot loop-derived peptides. Macrocyclic PepNats representing hot loops of inducible nitric oxide synthase (iNOS) and human agouti-related protein (AGRP) were synthesized on solid support employing macrocyclization by imine formation and subsequent stereoselective 1,3-dipolar cycloaddition as key steps. PepNats derived from the iNOS DINNN hot loop and the AGRP RFF hot spot sequence yielded novel and potent ligands of the SPRY domain-containing SOCS box protein 2 (SPSB2) that binds to iNOS, and selective ligands for AGRP-binding melanocortin (MC) receptors. NP-inspired fragment absolute configuration determines the conformation of the peptide part responsible for binding. These results demonstrate that combination of NP-inspired scaffolds with peptidic epitopes enables identification of novel hot loop mimics with conformationally constrained and biologically relevant structure.
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Péptidos Cíclicos/metabolismo , Receptores de Melanocortina/metabolismo , Proteínas Supresoras de la Señalización de Citocinas/metabolismo , Proteína Relacionada con Agouti/química , Proteína Relacionada con Agouti/metabolismo , Epítopos , Humanos , Óxido Nítrico Sintasa de Tipo II/química , Óxido Nítrico Sintasa de Tipo II/metabolismo , Péptidos Cíclicos/síntesis química , Péptidos Cíclicos/química , Unión Proteica , Conformación Proteica , EstereoisomerismoRESUMEN
Direct in vivo reprogramming of cardiac fibroblasts into myocytes is an attractive therapeutic intervention in resolving myogenic deterioration. Current transgene-dependent approaches can restore cardiac function, but dependence on retroviral delivery and persistent retention of transgenic sequences are significant therapeutic hurdles. Chemical reprogramming has been established as a legitimate method to generate functional cell types, including those of the cardiac lineage. Here, we have extended this approach to generate progenitor cells that can differentiate into endothelial cells and cardiomyocytes using a single inhibitor protocol. Depletion of terminally differentiated cells and enrichment for proliferative cells result in a second expandable progenitor population that can robustly give rise to myofibroblasts and smooth muscle. Deployment of a genome-wide knockout screen with clustered regularly interspaced short palindromic repeats-guide RNA library to identify novel mediators that regulate the reprogramming revealed the involvement of DNA methyltransferase 1-associated protein 1 (Dmap1). Loss of Dmap1 reduced promoter methylation, increased the expression of Nkx2-5, and enhanced the retention of self-renewal, although further differentiation is inhibited because of the sustained expression of Cdh1. Our results hence establish Dmap1 as a modulator of cardiac reprogramming and myocytic induction. Stem Cells 2019;37:958-972.
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Benzamidas/farmacología , Sistemas CRISPR-Cas , Reprogramación Celular/efectos de los fármacos , Dioxoles/farmacología , Fibroblastos/efectos de los fármacos , Pirazoles/farmacología , Piridinas/farmacología , Proteínas Represoras/genética , Células Madre/efectos de los fármacos , Animales , Cadherinas/genética , Cadherinas/metabolismo , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Reprogramación Celular/genética , Fibroblastos/citología , Fibroblastos/metabolismo , Edición Génica/métodos , Proteína Homeótica Nkx-2.5/genética , Proteína Homeótica Nkx-2.5/metabolismo , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Liso/citología , Músculo Liso/metabolismo , Miocardio/citología , Miocardio/metabolismo , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Cultivo Primario de Células , ARN Guía de Kinetoplastida/genética , ARN Guía de Kinetoplastida/metabolismo , Proteínas Represoras/metabolismo , Células Madre/citología , Células Madre/metabolismoRESUMEN
The mammalian heart undergoes maturation during postnatal life to meet the increased functional requirements of an adult. However, the key drivers of this process remain poorly defined. We are currently unable to recapitulate postnatal maturation in human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), limiting their potential as a model system to discover regenerative therapeutics. Here, we provide a summary of our studies, where we developed a 96-well device for functional screening in human pluripotent stem cell-derived cardiac organoids (hCOs). Through interrogation of >10,000 organoids, we systematically optimize parameters, including extracellular matrix (ECM), metabolic substrate, and growth factor conditions, that enhance cardiac tissue viability, function, and maturation. Under optimized maturation conditions, functional and molecular characterization revealed that a switch to fatty acid metabolism was a central driver of cardiac maturation. Under these conditions, hPSC-CMs were refractory to mitogenic stimuli, and we found that key proliferation pathways including ß-catenin and Yes-associated protein 1 (YAP1) were repressed. This proliferative barrier imposed by fatty acid metabolism in hCOs could be rescued by simultaneous activation of both ß-catenin and YAP1 using genetic approaches or a small molecule activating both pathways. These studies highlight that human organoids coupled with higher-throughput screening platforms have the potential to rapidly expand our knowledge of human biology and potentially unlock therapeutic strategies.
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Factores Biológicos/metabolismo , Puntos de Control del Ciclo Celular , Miocitos Cardíacos/metabolismo , Organoides/metabolismo , Células Madre Pluripotentes/metabolismo , Regeneración/fisiología , Adulto , Animales , Diferenciación Celular , Daño del ADN , Humanos , Masculino , Miocitos Cardíacos/citología , Organoides/citología , Células Madre Pluripotentes/citología , Ratas Sprague-DawleyRESUMEN
An assessment of the C-H activation catalyst [(COD)Ir(IMes)(PPh3 )]PF6 (COD=1,5-cyclooctadiene, IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) in the deuteration of phenyl rings containing different functional directing groups is divulged. Competition experiments have revealed a clear order of the directing groups in the hydrogen isotope exchange (HIE) with an iridiumâ (I) catalyst. Through DFT calculations the iridium-substrate coordination complex has been identified to be the main trigger for reactivity and selectivity in the competition situation with two or more directing groups. We postulate that the competition concept found in this HIE reaction can be used to explain regioselectivities in other transition-metal-catalyzed functionalization reactions of complex drug-type molecules as long as a C-H activation mechanism is involved.
RESUMEN
Over 5 million people in the United States suffer from heart failure, due to the limited ability to regenerate functional cardiac tissue. One potential therapeutic strategy is to enhance proliferation of resident cardiomyocytes. However, phenotypic screening for therapeutic agents is challenged by the limited ability of conventional markers to discriminate between cardiomyocyte proliferation and endoreplication (e.g. polyploidy and multinucleation). Here, we developed a novel assay that combines automated live-cell microscopy and image processing algorithms to discriminate between proliferation and endoreplication by quantifying changes in the number of nuclei, changes in the number of cells, binucleation, and nuclear DNA content. We applied this assay to further prioritize hits from a primary screen for DNA synthesis, identifying 30 compounds that enhance proliferation of human induced pluripotent stem cell-derived cardiomyocytes. Among the most active compounds from the phenotypic screen are clinically approved L-type calcium channel blockers from multiple chemical classes whose activities were confirmed across different sources of human induced pluripotent stem cell-derived cardiomyocytes. Identification of compounds that stimulate human cardiomyocyte proliferation may provide new therapeutic strategies for heart failure.
Asunto(s)
Canales de Calcio Tipo L/metabolismo , Células Madre Pluripotentes Inducidas/citología , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Proliferación Celular , ADN/biosíntesis , Humanos , Procesamiento de Imagen Asistido por Computador , Fenotipo , PloidiasRESUMEN
Our ever-increasing understanding of biological systems is providing a range of exciting novel biological targets, whose modulation may enable novel therapeutic options for many diseases. These targets include protein-protein and protein-nucleic acid interactions, which are, however, often refractory to classical small-molecule approaches. Other types of molecules, or modalities, are therefore required to address these targets, which has led several academic research groups and pharmaceutical companies to increasingly use the concept of so-called "new modalities". This Review defines for the first time the scope of this term, which includes novel peptidic scaffolds, oligonucleotides, hybrids, molecular conjugates, as well as new uses of classical small molecules. We provide the most representative examples of these modalities to target large binding surface areas such as those found in protein-protein interactions and for biological processes at the center of cell regulation.
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Descubrimiento de Drogas , Ácidos Nucleicos/antagonistas & inhibidores , Oligonucleótidos/farmacología , Proteínas/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/farmacología , Humanos , Ácidos Nucleicos/química , Oligonucleótidos/química , Proteínas/química , Bibliotecas de Moléculas Pequeñas/química , Propiedades de SuperficieRESUMEN
Regenerative therapies hold great potential to change the treatment paradigm for cardiac diseases. Human cardiac progenitor cells can be used for drug discovery in this area and also provide a renewable source of cardiomyocytes. However, a better understanding of their characteristics is critical for interpreting data obtained from drug screening using these cells. In the present study, we performed global transcriptional analysis of two important sources of cardiac progenitors, i.e., patient epicardium-derived cells (EPDCs) and cardiac progenitor cells (CPCs) derived from human induced pluripotent stem cells. In addition, we also compared the gene expression profiles of these cells when they were cultured under normoxic and hypoxic conditions. We identified 3,289 mRNAs that were differentially expressed between EPDCs and CPCs. Gene ontology annotation and pathway enrichment analyses further revealed possible unique functions of these two cell populations. Notably, the impact of hypoxia vs normoxia on gene expression was modest and only a few genes (e.g., AK4, ALDOC, BNIP3P1, PGK1, and SLC2A1) were upregulated in EPDCs and CPCs after the cells were exposed to low oxygen for 24 h. Finally, we also performed a focused analysis of the gene expression patterns of a predefined set of 92 paracrine factors. We identified 30 of these genes as differentially expressed, and 29 were expressed at higher levels in EPDCs compared with CPCs. Taken together, the results of the present study advance our understanding of the transcriptional programs in EPDCs and CPCs and highlights important differences and similarities between these cell populations.
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Perfilación de la Expresión Génica , Células Madre Pluripotentes Inducidas/metabolismo , Miocitos Cardíacos/citología , Pericardio/citología , Biomarcadores/metabolismo , Hipoxia de la Célula/efectos de los fármacos , Hipoxia de la Célula/genética , Análisis por Conglomerados , Regulación de la Expresión Génica/efectos de los fármacos , Ontología de Genes , Humanos , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Anotación de Secuencia Molecular , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Oxígeno/farmacología , Comunicación Paracrina/genética , Mapas de Interacción de Proteínas/efectos de los fármacos , Mapas de Interacción de Proteínas/genéticaRESUMEN
Following a heart attack, more than a billion cardiac muscle cells (cardiomyocytes) can be killed, leading to heart failure and sudden death. Much research in this area is now focused on the regeneration of heart tissue through differentiation of stem cells, proliferation of existing cardiomyocytes and cardiac progenitor cells, and reprogramming of fibroblasts into cardiomyocytes. Different chemical modalities (i.e. methods or agents), ranging from small molecules and RNA approaches (including both microRNA and anti-microRNA) to modified peptides and proteins, are showing potential to meet this medical need. In this Review, we outline the recent advances in these areas and describe both the modality and progress, including novel screening strategies to identify hits, and the upcoming challenges and opportunities to develop these hits into pharmaceuticals, at which chemistry plays a key role.
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Miocitos Cardíacos/metabolismo , Medicina Regenerativa/métodos , Diferenciación Celular , Descubrimiento de Drogas , Humanos , Miocitos Cardíacos/citologíaRESUMEN
Mammalian hearts lose their regenerative potential shortly after birth. Stimulating the proliferation of preexisting cardiomyocytes is a potential therapeutic strategy for cardiac damage. In a previous study, we identified 30 compounds that induced the bona-fide proliferation of human iPSC-derived cardiomyocytes (hiPSC-CM). Here, we selected five active compounds with diverse targets, including ALK5 and CB1R, and performed multi-omic analyses to identify common mechanisms mediating the cell cycle progression of hiPSC-CM. Transcriptome profiling revealed the top enriched pathways for all compounds including cell cycle, DNA repair, and kinesin pathways. Functional proteomic arrays found that the compounds collectively activated multiple receptor tyrosine kinases including ErbB2, IGF1R, and VEGFR2. Network analysis integrating common transcriptomic and proteomic signatures predicted that MAPK/PI3K pathways mediated compound responses. Furthermore, VEGFR2 negatively regulated endoreplication, enabling the completion of cell division. Thus, in this study, we applied high-content imaging and molecular profiling to establish mechanisms linking pro-proliferative agents to mechanisms of cardiomyocyte cell cycling.
RESUMEN
A novel series of DGAT-1 inhibitors was discovered from an oxadiazole amide high throughput screening (HTS) hit. Optimisation of potency and ligand lipophilicity efficiency (LLE) resulted in a carboxylic acid containing clinical candidate 53 (AZD3988), which demonstrated excellent DGAT-1 potency (0.6 nM), good pharmacokinetics and pre-clinical in vivo efficacy that could be rationalised through a PK/PD relationship.
Asunto(s)
Diacilglicerol O-Acetiltransferasa/antagonistas & inhibidores , Inhibidores Enzimáticos/síntesis química , Hipoglucemiantes/síntesis química , Oxadiazoles/síntesis química , Animales , Diabetes Mellitus/tratamiento farmacológico , Diacilglicerol O-Acetiltransferasa/metabolismo , Perros , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/farmacología , Semivida , Ensayos Analíticos de Alto Rendimiento , Humanos , Hipoglucemiantes/farmacocinética , Hipoglucemiantes/farmacología , Ligandos , Ratones , Obesidad/tratamiento farmacológico , Oxadiazoles/farmacocinética , Relación Estructura-Actividad Cuantitativa , RatasRESUMEN
In this work, cysteine staples were used as a late-stage functionalization strategy to diversify peptides and build conjugates targeting the melanocortin G-protein-coupled receptors [melanocortin receptor-1 (MC1R) and MC3R-MC5R]. Monocyclic and bicyclic agonists based on sunflower trypsin inhibitor-1 were used to generate a selection of stapled peptides that were evaluated for binding (pKi) and functional activation (pEC50) of the melanocortin receptor subtypes. Stapled peptides generally had improved activity, with aromatic stapled peptides yielding selective MC1R agonists, including a xylene-stapled peptide (2) with an EC50 of 1.9 nM for MC1R and >150-fold selectivity for MC3R and MC4R. Selected stapled peptides were further functionalized with linkers and payloads, generating a series of conjugated peptides with potent MC1R activity, including one pyridazine-functionalized peptide (21) with picomolar activity at MC1R (Ki 58 pM; EC50 < 9 pM). This work demonstrates that staples can be used as modular synthetic tools to tune potency and selectivity in peptide-based drug design.
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Piridazinas , Receptor de Melanocortina Tipo 1 , Cisteína , Melanocortinas , Péptidos/farmacología , Receptor de Melanocortina Tipo 1/agonistas , Receptor de Melanocortina Tipo 3 , Receptor de Melanocortina Tipo 4 , Receptores de Melanocortina/metabolismo , Relación Estructura-Actividad , XilenosRESUMEN
Inhibition of acetyl-CoA carboxylases has the potential for modulating long chain fatty acid biosynthesis and mitochondrial fatty acid oxidation. Hybridization of weak inhibitors of ACC2 provided a novel, moderately potent but lipophilic series. Optimization led to compounds 33 and 37, which exhibit potent inhibition of human ACC2, 10-fold selectivity over inhibition of human ACC1, good physical and in vitro ADME properties and good bioavailability. X-ray crystallography has shown this series binding in the CT-domain of ACC2 and revealed two key hydrogen bonding interactions. Both 33 and 37 lower levels of hepatic malonyl-CoA in vivo in obese Zucker rats.
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Acetil-CoA Carboxilasa/antagonistas & inhibidores , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Obesidad/tratamiento farmacológico , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Acetil-CoA Carboxilasa/metabolismo , Animales , Cristalografía por Rayos X , Diabetes Mellitus Tipo 2/enzimología , Diseño de Fármacos , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/uso terapéutico , Ácidos Grasos/metabolismo , Humanos , Hígado/efectos de los fármacos , Hígado/enzimología , Masculino , Malonil Coenzima A/metabolismo , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Obesidad/enzimología , Ratas , Ratas Zucker , Bibliotecas de Moléculas Pequeñas/farmacocinética , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Relación Estructura-ActividadRESUMEN
We have designed a new class of highly potent bivalent melanocortin receptor ligands based on the nature-derived bicyclic peptide sunflower trypsin inhibitor 1 (SFTI-1). Incorporation of melanotropin pharmacophores in each of the two turn regions of SFTI-1 resulted in substantial gains in agonist activity particularly at human melanocortin receptors 1 and 3 (hMC1R/hMC3R) compared to monovalent analogues. In in vitro binding and functional assays, the most potent molecule, compound 6, displayed low picomolar agonist activity at hMC1R (pEC50 > 10.3; EC50 < 50 pM; pKi: 10.16 ± 0.04; Ki: 69 ± 5 pM) and is at least 30-fold more selective for this receptor than for hMC3R, hMC4R, or hMC5R. The results are discussed in the context of structural homology models of hMCRs in complex with the developed bivalent ligands.
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Péptidos Cíclicos/farmacología , Receptor de Melanocortina Tipo 1/agonistas , Relación Dosis-Respuesta a Droga , Humanos , Modelos Moleculares , Estructura Molecular , Péptidos Cíclicos/síntesis química , Péptidos Cíclicos/química , Relación Estructura-ActividadRESUMEN
A series of carboxylic acid glycogen phosphorylase inhibitors, which have potential as oral antidiabetic agents, is described. Defining and applying simple physicochemical design criteria was used to assess the opportunity and to focus synthetic efforts on compounds with the greatest probability of success. The study led to compound 17, which exhibits a good balance of properties including potent inhibition of recombinant human liver glycogen phosphorylase in vitro, a good DMPK profile including excellent bioavailability and low clearance and good in vivo activity in a glucagon challenge model of diabetes in Zucker rats.
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Ácidos Carboxílicos/farmacología , Glucógeno Fosforilasa de Forma Hepática/antagonistas & inhibidores , Hipoglucemiantes/química , Indanos/farmacología , Animales , Disponibilidad Biológica , Ácidos Carboxílicos/química , Ácidos Carboxílicos/uso terapéutico , Descubrimiento de Drogas , Humanos , Hipoglucemiantes/farmacología , Indanos/química , Indanos/uso terapéutico , Ratas , Ratas ZuckerRESUMEN
Artificial intelligence offers promising solutions for property prediction, compound design, and retrosynthetic planning, which are expected to significantly accelerate the search for pharmacologically relevant molecules. Here, we investigate aspects of artificial intelligence based de novo design pertaining to its integration into real-life workflows. First, different chemical spaces were used as training sets for reinforcement learning (RL) in combination with different reward functions. With the trained neuronal networks different biologically active molecules could be regenerated. Excluding molecules with substructures such as five-membered rings from training spaces nevertheless produced results containing these moieties. Furthermore, different scoring functions in RL were investigated and produced different design ensembles. In summary, some of these design proposals are close in chemical space to the query, thus supporting lead optimization, while 3D-shape or QSAR (quantitative structure-activity relationship) models produced significantly different proposals by sampling a broader region of the chemical space, thus supporting lead generation. Therefore, RL provides a good framework to tailored design approaches for different discovery phases.
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Química Farmacéutica/métodos , Diseño de Fármacos , Redes Neurales de la Computación , Compuestos Orgánicos/química , Bases de Datos de Compuestos Químicos , Conjuntos de Datos como Asunto , Inhibidores del Factor Xa/químicaRESUMEN
Cardiac progenitor cells (CPCs), capable of differentiating into multiple cardiac cell types including cardiomyocytes (CMs), endothelial cells, and smooth muscle cells, are promising candidates for cardiac repair/regeneration. In vitro model systems where cells are grown in a more in vivo-like environment, such as 3D cultures, have been shown to be more predictive than 2D culture for studying cell biology and disease pathophysiology. In this report, we focused on using Wnt inhibitors to study the differentiation of human iPSC-CPCs under 2D or 3D culture conditions by measuring marker protein and gene expression as well as intracellular Ca2+ oscillation. Our results show that the 3D culture with aligned nanofiber scaffolds, mimicing the architecture of the extracellular matrix of the heart, improve the differentiation of iPSC-CPCs to functional cardiomyocytes induced by Wnt inhibition, as shown with increased number of cardiac Troponin T (cTnT)-positive cells and synchronized intracellular Ca2+ oscillation. In addition, we studied if 3D nanofiber culture can be used as an in vitro model for compound screening by testing a number of other differentiation factors including a ALK5 inhibitor and inhibitors of BMP signaling. This work highlights the importance of using a more relevant in vitro model and measuring not only the expression of marker proteins but also the functional readout in a screen in order to identify the best compounds and to investigate the resulting biology.
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Diferenciación Celular , Células Madre Pluripotentes Inducidas/citología , Miocitos Cardíacos/citología , Nanofibras/química , Células Madre/citología , Andamios del Tejido , Proteínas Morfogenéticas Óseas/antagonistas & inhibidores , Células Cultivadas , Humanos , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Células Madre Pluripotentes Inducidas/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Receptor Tipo I de Factor de Crecimiento Transformador beta/antagonistas & inhibidores , Transducción de Señal , Células Madre/efectos de los fármacos , Células Madre/metabolismoRESUMEN
Identification of small molecules with the potential to selectively proliferate cardiac progenitor cells (CPCs) will aid our understanding of the signaling pathways and mechanisms involved and could ultimately provide tools for regenerative therapies for the treatment of post-MI cardiac dysfunction. We have used an in vitro human induced pluripotent stem cell-derived CPC model to screen a 10,000-compound library containing molecules representing different target classes and compounds reported to modulate the phenotype of stem or primary cells. The primary readout of this phenotypic screen was proliferation as measured by nuclear count. We identified retinoic acid receptor (RAR) agonists as potent proliferators of CPCs. The CPCs retained their progenitor phenotype following proliferation and the identified RAR agonists did not proliferate human cardiac fibroblasts, the major cell type in the heart. In addition, the RAR agonists were able to proliferate an independent source of CPCs, HuES6. The RAR agonists had a time-of-differentiation-dependent effect on the HuES6-derived CPCs. At 4 days of differentiation, treatment with retinoic acid induced differentiation of the CPCs to atrial cells. However, after 5 days of differentiation treatment with RAR agonists led to an inhibition of terminal differentiation to cardiomyocytes and enhanced the proliferation of the cells. RAR agonists, at least transiently, enhance the proliferation of human CPCs, at the expense of terminal cardiac differentiation. How this mechanism translates in vivo to activate endogenous CPCs and whether enhancing proliferation of these rare progenitor cells is sufficient to enhance cardiac repair remains to be investigated.
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Miocitos Cardíacos/metabolismo , Receptores de Ácido Retinoico/agonistas , Células Madre/metabolismo , Humanos , FenotipoRESUMEN
Artificial intelligence (AI) tools are increasingly being applied in drug discovery. While some protagonists point to vast opportunities potentially offered by such tools, others remain sceptical, waiting for a clear impact to be shown in drug discovery projects. The reality is probably somewhere in-between these extremes, yet it is clear that AI is providing new challenges not only for the scientists involved but also for the biopharma industry and its established processes for discovering and developing new medicines. This article presents the views of a diverse group of international experts on the 'grand challenges' in small-molecule drug discovery with AI and the approaches to address them.
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Inteligencia Artificial , Diseño de Fármacos , Descubrimiento de Drogas/métodos , HumanosRESUMEN
Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease that can lead to irreversible liver cirrhosis and cancer. Early diagnosis of NASH is vital to detect disease before it becomes life-threatening, yet noninvasively differentiating NASH from simple steatosis is challenging. Herein, bifunctional probes have been developed that target the hepatocyte-specific asialoglycoprotein receptor (ASGPR), the expression of which decreases during NASH progression. The results show that the probes allow longitudinal, noninvasive monitoring of ASGPR levels by positron emission tomography in the newly developed rat model of NASH. The probes open new possibilities for research into early diagnosis of NASH and development of drugs to slow or reverse its progression.