RESUMEN
Iron is an essential metal for all organisms, yet disruption of its homeostasis, particularly in labile forms that can contribute to oxidative stress, is connected to diseases ranging from infection to cancer to neurodegeneration. Iron deficiency is also among the most common nutritional deficiencies worldwide. To advance studies of iron in healthy and disease states, we now report the synthesis and characterization of iron-caged luciferin-1 (ICL-1), a bioluminescent probe that enables longitudinal monitoring of labile iron pools (LIPs) in living animals. ICL-1 utilizes a bioinspired endoperoxide trigger to release d-aminoluciferin for selective reactivity-based detection of Fe2+ with metal and oxidation state specificity. The probe can detect physiological changes in labile Fe2+ levels in live cells and mice experiencing iron deficiency or overload. Application of ICL-1 in a model of systemic bacterial infection reveals increased iron accumulation in infected tissues that accompany transcriptional changes consistent with elevations in both iron acquisition and retention. The ability to assess iron status in living animals provides a powerful technology for studying the contributions of iron metabolism to physiology and pathology.
Asunto(s)
Infecciones por Acinetobacter/metabolismo , Anemia Ferropénica/metabolismo , Luciferina de Luciérnaga/análisis , Colorantes Fluorescentes/análisis , Sobrecarga de Hierro/metabolismo , Hierro/metabolismo , 2,2'-Dipiridil/farmacología , Infecciones por Acinetobacter/genética , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/patología , Acinetobacter baumannii/patogenicidad , Acinetobacter baumannii/fisiología , Anemia Ferropénica/genética , Anemia Ferropénica/patología , Animales , Proteínas de Transporte de Catión/genética , Proteínas de Transporte de Catión/metabolismo , Cationes Bivalentes , Modelos Animales de Enfermedad , Compuestos Férricos/farmacología , Luciferina de Luciérnaga/análogos & derivados , Luciferina de Luciérnaga/síntesis química , Colorantes Fluorescentes/síntesis química , Regulación de la Expresión Génica , Hepcidinas/genética , Hepcidinas/metabolismo , Homeostasis/genética , Sobrecarga de Hierro/genética , Sobrecarga de Hierro/patología , Proteína 1 Reguladora de Hierro/genética , Proteína 1 Reguladora de Hierro/metabolismo , Proteína 2 Reguladora de Hierro/genética , Proteína 2 Reguladora de Hierro/metabolismo , Mediciones Luminiscentes , Ratones , Ratones Transgénicos , Compuestos de Amonio Cuaternario/farmacología , Receptores de Transferrina/genética , Receptores de Transferrina/metabolismo , Transducción de Señal , Transferrina/genética , Transferrina/metabolismoRESUMEN
Improved methods for studying intracellular reactive Fe(II) are of significant interest for studies of iron metabolism and disease-relevant changes in iron homeostasis. Here we describe a highly selective reactivity-based probe in which a Fenton-type reaction with intracellular labile Fe(II) leads to unmasking of the aminonucleoside puromycin. Puromycin leaves a permanent and dose-dependent mark on treated cells that can be detected with high sensitivity and precision using a high-content, plate-based immunofluorescence assay. Using this new probe and screening approach, we detected alteration of cellular labile Fe(II) in response extracellular iron conditioning, overexpression of iron storage and/or export proteins, and post-translational regulation of iron export. We also used this new tool to demonstrate that labile Fe(II) pools are larger in cancer cells than in nontumorigenic cells.
Asunto(s)
Compuestos Ferrosos/análisis , Compuestos Ferrosos/metabolismo , Colorantes Fluorescentes/análisis , Colorantes Fluorescentes/química , Técnica del Anticuerpo Fluorescente , Colorantes Fluorescentes/síntesis química , Humanos , Estructura Molecular , Puromicina/química , Puromicina/farmacología , Compuestos de Espiro/análisis , Compuestos de Espiro/síntesis química , Compuestos de Espiro/químicaRESUMEN
A generic activation mode for asymmetric LUMO-lowering catalysis has been developed using the long-established principles of oxy-allyl cation chemistry. Here, the enantioselective conversion of racemic α-tosyloxy ketones to optically enriched α-indolic carbonyls has been accomplished using a new amino alcohol catalyst in the presence of electron-rich indole nucleophiles. Kinetic studies reveal that the rate-determining step in this S(N)1 pathway is the catalyst-mediated α-tosyloxy ketone deprotonation step to form an enantiodiscriminant oxy-allyl cation prior to the stereodefining nucleophilic addition event.
Asunto(s)
Compuestos Alílicos/química , Indoles/síntesis química , Cetonas/química , Oxígeno/química , Catálisis , Cationes/química , Indoles/química , Estructura Molecular , EstereoisomerismoRESUMEN
The first enantioselective aldehyde α-benzylation using electron-deficient aryl and heteroaryl substrates has been accomplished. The productive merger of a chiral imidazolidinone organocatalyst and a commercially available iridium photoredox catalyst in the presence of household fluorescent light directly affords the desired homobenzylic stereogenicity in good to excellent yield and enantioselectivity. The utility of this methodology has been demonstrated via rapid access to an enantioenriched drug target for angiogenesis suppression.
Asunto(s)
Aldehídos/química , Aldehídos/síntesis química , Imidazolidinas/química , Catálisis , Cristalografía por Rayos X , Iridio/química , Modelos Moleculares , Estructura Molecular , Oxidación-Reducción , Fotoquímica , EstereoisomerismoRESUMEN
Aberrant histone methylation profile is reported to correlate with the development and progression of NAFLD during obesity. However, the identification of specific epigenetic modifiers involved in this process remains poorly understood. Here, we identify the histone demethylase Plant Homeodomain Finger 2 (Phf2) as a new transcriptional co-activator of the transcription factor Carbohydrate Responsive Element Binding Protein (ChREBP). By specifically erasing H3K9me2 methyl-marks on the promoter of ChREBP-regulated genes, Phf2 facilitates incorporation of metabolic precursors into mono-unsaturated fatty acids, leading to hepatosteatosis development in the absence of inflammation and insulin resistance. Moreover, the Phf2-mediated activation of the transcription factor NF-E2-related factor 2 (Nrf2) further reroutes glucose fluxes toward the pentose phosphate pathway and glutathione biosynthesis, protecting the liver from oxidative stress and fibrogenesis in response to diet-induced obesity. Overall, our findings establish a downstream epigenetic checkpoint, whereby Phf2, through facilitating H3K9me2 demethylation at specific gene promoters, protects liver from the pathogenesis progression of NAFLD.