RESUMEN
Advancing our knowledge of how neural stem cell (NSC) behavior in the adult hippocampus is regulated has implications for elucidating basic mechanisms of learning and memory as well as for neurodegenerative disease therapy. To date, numerous biochemical cues from the endogenous hippocampal NSC niche have been identified as modulators of NSC quiescence, proliferation, and differentiation; however, the complex repertoire of signaling factors within stem cell niches raises the question of how cues act in combination with one another to influence NSC physiology. To help overcome experimental bottlenecks in studying this question, we adapted a high-throughput microculture system, with over 500 distinct microenvironments, to conduct a systematic combinatorial screen of key signaling cues and collect high-content phenotype data on endpoint NSC populations. This novel application of the platform consumed only 0.2% of reagent volumes used in conventional 96-well plates, and resulted in the discovery of numerous statistically significant interactions among key endogenous signals. Antagonistic relationships between fibroblast growth factor 2, transforming growth factor ß (TGF-ß), and Wnt-3a were found to impact NSC proliferation and differentiation, whereas a synergistic relationship between Wnt-3a and Ephrin-B2 on neuronal differentiation and maturation was found. Furthermore, TGF-ß and bone morphogenetic protein 4 combined with Wnt-3a and Ephrin-B2 resulted in a coordinated effect on neuronal differentiation and maturation. Overall, this study offers candidates for further elucidation of significant mechanisms guiding NSC fate choice and contributes strategies for enhancing control over stem cell-based therapies for neurodegenerative diseases.
Asunto(s)
Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Hipocampo/citología , Péptidos y Proteínas de Señalización Intercelular/aislamiento & purificación , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Células-Madre Neurales/efectos de los fármacos , Transducción de Señal , Adulto , Ensayos Analíticos de Alto Rendimiento , HumanosRESUMEN
A 3D cell culture chip was used for high-throughput screening of a human neural progenitor cell line. The differential toxicity of 24 compounds was determined on undifferentiated and differentiating NPCs. Five compounds led to significant differences in IC50 values between undifferentiated and differentiating cultures. This platform has potential use in phenotypic screening to elucidate molecular toxicology on human stem cells.
Asunto(s)
Descubrimiento de Drogas , Ensayos Analíticos de Alto Rendimiento , Células-Madre Neurales/efectos de los fármacos , Células-Madre Neurales/metabolismo , Fenotipo , Técnicas de Cultivo de Célula , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/genética , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Relación Dosis-Respuesta a Droga , Humanos , Células-Madre Neurales/citología , Análisis de Secuencia por Matrices de Oligonucleótidos , Pruebas de Toxicidad AgudaRESUMEN
Ionic liquids (ILs) are ionic compounds that are liquid at room temperature. We studied the spontaneous mixing behavior between two ILs, ethylammonium nitrate (EAN) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and observed notable phenomena. Experimental studies showed that the interface between the two ILs was unusually long-lived, despite the ILs being miscible with one another. Molecular dynamics (MD) simulations supported these findings and provided insight into the micromixing behavior of the ILs. We found that not only did the ions experience slow diffusion as they mix but also exhibited significant ordering into distinct regions. We suspect that this ordering disrupted concentration gradients in the direction normal to the interface, thus hindering diffusion in this direction and allowing the macroscopic interface to remain for long periods of time. Intermolecular interactions responsible for this behavior included the O-NH interaction between the EAN ions and the carbon chain-carbon chain interactions between the [BMIM](+) cations, which associate more strongly in the mixed state than in the pure IL state.
Asunto(s)
Imidazoles/química , Líquidos Iónicos/química , Compuestos de Amonio Cuaternario/química , Modelos Moleculares , Simulación de Dinámica MolecularRESUMEN
AIM: Two unexplored aspects for irinotecan and cisplatin (I&C) combination chemotherapy are: actively targeting both drugs to a specific diseased cell type, and delivering both drugs on the same vehicle to ensure their synchronized entry into the cell at a well-defined ratio. In this work, the authors report the use of targeted polymeric nanoparticles (NPs) to coencapsulate and deliver I&C to cancer cells expressing the prostate-specific membrane antigen. MATERIALS & METHODS: Targeted NPs were prepared in a single step by mixing four different precursors inside microfluidic devices. RESULTS: I&C were encapsulated in 55-nm NPs and showed an eightfold increase in internalization by prostate-specific membrane antigen-expressing LNCaP cells compared with nontargeted NPs. NPs coencapsulating both drugs exhibited strong synergism in LNCaP cells with a combination index of 0.2. CONCLUSION: The strategy of coencapsulating both I&C in a single NP targeted to a specific cell type could potentially be used to treat different types of cancer.