RESUMO
Glucose is a major source of energy for most living organisms, and its aberrant uptake is linked to many pathological conditions. However, our understanding of disease-associated glucose flux is limited owing to the lack of robust tools. To date, positron-emission tomography imaging remains the gold standard for measuring glucose uptake, and no optical tools exist for non-invasive longitudinal imaging of this important metabolite in in vivo settings. Here, we report the development of a bioluminescent glucose-uptake probe for real-time, non-invasive longitudinal imaging of glucose absorption both in vitro and in vivo. In addition, we demonstrate that the sensitivity of our method is comparable with that of commonly used 18F-FDG-positron-emission-tomography tracers and validate the bioluminescent glucose-uptake probe as a tool for the identification of new glucose transport inhibitors. The new imaging reagent enables a wide range of applications in the fields of metabolism and drug development.
Assuntos
Transportador de Glucose Tipo 1/fisiologia , Glucose/metabolismo , Neoplasias Experimentais/diagnóstico por imagem , Neoplasias Experimentais/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Animais , Transporte Biológico , Feminino , Fluordesoxiglucose F18/metabolismo , Humanos , Luciferases/metabolismo , Camundongos Knockout , Camundongos Nus , Neoplasias Experimentais/patologia , Compostos Radiofarmacêuticos/metabolismo , Células Tumorais CultivadasRESUMO
Mitochondrial membrane potential (ΔΨm) is a universal selective indicator of mitochondrial function and is known to play a central role in many human pathologies, such as diabetes mellitus, cancer and Alzheimer's and Parkinson's diseases. Here, we report the design, synthesis and several applications of mitochondria-activatable luciferin (MAL), a bioluminescent probe sensitive to ΔΨm, and partially to plasma membrane potential (ΔΨp), for non-invasive, longitudinal monitoring of ΔΨm in vitro and in vivo. We applied this new technology to evaluate the aging-related change of ΔΨm in mice and showed that nicotinamide riboside (NR) reverts aging-related mitochondrial depolarization, revealing another important aspect of the mechanism of action of this potent biomolecule. In addition, we demonstrated application of the MAL probe for studies of brown adipose tissue (BAT) activation and non-invasive in vivo assessment of ΔΨm in animal cancer models, opening exciting opportunities for understanding the underlying mechanisms and for discovery of effective treatments for many human pathologies.
Assuntos
Envelhecimento/genética , Diagnóstico por Imagem/métodos , Luciferina de Vaga-Lumes/química , Corantes Fluorescentes/química , Neoplasias Mamárias Experimentais/diagnóstico por imagem , Potencial da Membrana Mitocondrial/genética , Adipócitos/citologia , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/diagnóstico por imagem , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Envelhecimento/efeitos dos fármacos , Envelhecimento/metabolismo , Animais , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Dioxóis/farmacologia , Feminino , Luciferina de Vaga-Lumes/metabolismo , Corantes Fluorescentes/metabolismo , Luciferases/genética , Luciferases/metabolismo , Medições Luminescentes , Neoplasias Mamárias Experimentais/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Camundongos Nus , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Nigericina/farmacologia , Compostos de PiridínioRESUMO
Because carbonyl groups are ubiquitous in organic chemistry, the ability to synthesize functionalized carbonyl compounds, particularly enantioselectively, is an important objective. We have developed a straightforward and versatile method for catalytic asymmetric carbon-carbon bond formation at the γ-position of carbonyl compounds, specifically, phosphine-catalyzed additions of malonate esters to γ-substituted allenoates and allenamides. Mechanistic studies have provided insight into the reaction pathway.
RESUMO
A new class of neutral cyclometalated iridium(III) complexes with enantiomerically pure C(1)-symmetric phenol-oxazolines (3a,b) have been synthetized in high yields and fully characterized. Resolution of the corresponding Δ(R) and Λ(R) or Δ(S) and Λ(S) isomers was easily achieved by conventional flash chromatography. The corresponding Δ and Λ helicities have been confirmed by CD spectroscopy and X-ray crystallography. Regarding the absorption and luminescence properties with unpolarized light, no significant difference between Δ and Λ isomers has been observed. A strong blue luminescence is observed for deaerated solutions of complexes 5a and 5b in CH(3)CN.
RESUMO
A new type of adaptive chiral thiophene-based ligands 3 has been designed and developed. The synthetic flexibility of the thienyl ring allowed for the preparation of polydendate C2-symmetric ligands in good yields, carrying simultaneously "hard" as well as "soft" coordinating atoms (i.e., N, S). The coordination attitude of 3 was then tested in the enantioselective base-free Cu(OAc)(2)-catalyzed addition of nitromethane to aromatic aldehydes, leading to the corresponding beta-nitro alcohols in excellent yields and enantiomeric excesses up to 86%.
RESUMO
Remarkable generality in scope of new C9-benzoylcupreines bearing electron-withdrawing substituents for the nitroaldol condensation with fluoromethyl ketones is presented. Both tri- and difluoromethyl ketones provided excellent levels of stereoinduction (ee 76-99%) under mild reaction conditions and low loading of catalyst (1-5 mol%).
Assuntos
Álcoois/síntese química , Cetonas/química , Nitrocompostos/síntese química , Álcoois/química , Catálise , Estrutura Molecular , Nitrocompostos/química , EstereoisomerismoRESUMO
Novel 4-alkylidene-beta-lactams with a polyphenolic side chain were synthesized and evaluated as radical scavengers. We have undertaken a detailed study of the antioxidant activity in vitro with chemical and biological testing of the new beta-lactams and of the corresponding methyl polyhydroxy benzoates. Antioxidant activity of beta-lactams and methyl benzoates was measured with the Briggs-Rauscher oscillating reaction, the TEAC (Trolox( Equivalent Antioxidant Capacity) assay, and as ability to inhibit ROS (=Reactive Oxygen Species) production on myoblast H9c2 cells. The results were discussed with regard to mechanism and correlated with structural parameters.
Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Flavonoides/química , Fenóis/química , beta-Lactamas/química , beta-Lactamas/farmacologia , Antioxidantes/síntese química , Antioxidantes/classificação , Benzoatos/química , Benzoatos/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Estrutura Molecular , Polifenóis , Relação Estrutura-Atividade , beta-Lactamas/síntese química , beta-Lactamas/classificaçãoRESUMO
A new poly(ethylene glycol)-modified DAT2-Cu(OAc)2 complex smoothly catalyzes a base-free nitroaldol condensation in a highly enantioselective manner (ee up to 93%) also in reagent-grade solvent and in the presence of air. Effective recovery and recycling (up to five runs) of supported catalysts are documented.
RESUMO
Enantiomerically pure diamino-bis(tert-thiophene) proved to be a valuable and flexible chiral ligand for Pd- and Zn-catalyzed transformations, allowing for high levels of stereocontrol in asymmetric allylic alkylation (ee up to 99%) and hydrosilylations of prochiral carbonyls (ee up to 97%).
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INTRODUCTION: Diagnosing prosthetic joint infection (PJI) poses significant challenges, and current modalities are fraught with low sensitivity and/or potential morbidity. Photoacoustic imaging (PAI) is a novel ultrasound-based modality with potential for diagnosing PJI safely and noninvasively. MATERIALS: In an established preclinical mouse model of bioluminescent Staphylococcus aureus PJI, fluorescent indocyanine green (ICG) was conjugated to ß-cyclodextrin (CDX-ICG) or teicoplanin (Teic-ICG) and injected intravenously for 1 week postoperatively. Daily fluorescent imaging and PAI were used to localize and quantify tracer signals. Results were analyzed using 2-way analysis of variance. RESULTS: Fluorescence clearly localized to the site of infection and was significantly higher with Teic-ICG compared with CDX-ICG (P = 0.046) and ICG alone (P = 0.0087). With PAI, the photoacoustic signal per volumetric analysis was substantially higher and better visualized with Teic-ICG compared with CDX-ICG and ICG alone, and colocalized well with bioluminescence and fluorescence imaging. CONCLUSION: Photoacoustic imaging successfully localized PJI in this proof-of-concept study and demonstrates potential for clinical translation in orthopaedics.
Assuntos
Artroplastia de Substituição/efeitos adversos , Técnicas Fotoacústicas/métodos , Infecções Relacionadas à Prótese/diagnóstico por imagem , Animais , Medições Luminescentes/métodos , Masculino , Camundongos Endogâmicos C57BL , Imagem Óptica/métodosRESUMO
PURPOSE: Most effective antitumor therapies induce tumor cell death. Non-invasive, rapid and accurate quantitative imaging of cell death is essential for monitoring early response to antitumor therapies. To facilitate this, we previously developed a biocompatible necrosis-avid near-infrared fluorescence (NIRF) imaging probe, HQ4, which was radiolabeled with 111Indium-chloride (111In-Cl3) via the chelate diethylene triamine pentaacetic acid (DTPA), to enable clinical translation. The aim of the present study was to evaluate the application of HQ4-DTPA for monitoring tumor cell death induced by radiation therapy. Apart from its NIRF and radioactive properties, HQ4-DTPA was also tested as a photoacoustic imaging probe to evaluate its performance as a multimodal contrast agent for superficial and deep tissue imaging. MATERIALS AND METHODS: Radiation-induced tumor cell death was examined in a xenograft mouse model of human breast cancer (MCF-7). Tumors were irradiated with three fractions of 9 Gy each. HQ4-DTPA was injected intravenously after the last irradiation, NIRF and photoacoustic imaging of the tumors were performed at 12, 20, and 40 h after injection. Changes in probe accumulation in the tumors were measured in vivo, and ex vivo histological analysis of excised tumors was performed at experimental endpoints. In addition, biodistribution of radiolabeled [111In]DTPA-HQ4 was assessed using hybrid single-photon emission computed tomography-computed tomography (SPECT-CT) at the same time points. RESULTS: In vivo NIRF imaging demonstrated a significant difference in probe accumulation between control and irradiated tumors at all time points after injection. A similar trend was observed using in vivo photoacoustic imaging, which was validated by ex vivo tissue fluorescence and photoacoustic imaging. Serial quantitative radioactivity measurements of probe biodistribution further demonstrated increased probe accumulation in irradiated tumors. CONCLUSION: HQ4-DTPA has high specificity for dead cells in vivo, potentiating its use as a contrast agent for determining the relative level of tumor cell death following radiation therapy using NIRF, photoacoustic imaging and SPECT in vivo. Initial preclinical results are promising and indicate the need for further evaluation in larger cohorts. If successful, such studies may help develop a new multimodal method for non-invasive and dynamic deep tissue imaging of treatment-induced cell death to quantitatively assess therapeutic response in patients.
RESUMO
PURPOSE: Recently we showed that a number of carboxylated near-infrared fluorescent (NIRF) cyanine dyes possess strong necrosis avid properties in vitro as well as in different mouse models of spontaneous and therapy-induced tumor necrosis, indicating their potential use for cancer diagnostic- and prognostic purposes. In the previous study, the detection of the cyanines was achieved by whole body optical imaging, a technique that, due to the limited penetration of near-infrared light, is not suitable for investigations deeper than 1 cm within the human body. Therefore, in order to facilitate clinical translation, the purpose of the present study was to generate a necrosis avid cyanine-based NIRF probe that could also be used for single photon emission computed tomography (SPECT). For this, the necrosis avid NIRF cyanine HQ4 was radiolabeled with 111indium, via the chelate diethylene triamine pentaacetic acid (DTPA). PROCEDURES: The necrosis avid properties of the radiotracer [111In]DTPA-HQ4 were examined in vitro and in vivo in different breast tumor models in mice using SPECT and optical imaging. Moreover, biodistribution studies were performed to examine the pharmacokinetics of the probe in vivo. RESULTS: Using optical imaging and radioactivity measurements, in vitro, we showed selective accumulation of [111In]DTPA-HQ4 in dead cells. Using SPECT and in biodistribution studies, the necrosis avidity of the radiotracer was confirmed in a 4T1 mouse breast cancer model of spontaneous tumor necrosis and in a MCF-7 human breast cancer model of chemotherapy-induced tumor necrosis. CONCLUSIONS: The radiotracer [111In]DTPA-HQ4 possessed strong and selective necrosis avidity in vitro and in various mouse models of tumor necrosis in vivo, indicating its potential to be clinically applied for diagnostic purposes and to monitor anti-cancer treatment efficacy.
Assuntos
Carbocianinas/química , Imagem Multimodal/métodos , Neoplasias/diagnóstico por imagem , Neoplasias/patologia , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Radioisótopos de Índio/química , Camundongos Endogâmicos BALB C , Camundongos Nus , Necrose , Imagem Óptica , Ácido Pentético/química , Distribuição TecidualRESUMO
Novel, clinically relevant, approaches to shift energy balance are urgently needed to combat metabolic disorders such as obesity and diabetes. One promising approach has been the expansion of brown adipose tissues that express uncoupling protein (UCP) 1 and thus can uncouple mitochondrial respiration from ATP synthesis. While expansion of UCP1-expressing adipose depots may be achieved in rodents via genetic and pharmacological manipulations or the transplantation of brown fat depots, these methods are difficult to use for human clinical intervention. We present a novel cell scaffold technology optimized to establish functional brown fat-like depots in vivo. We adapted the biophysical properties of hyaluronic acid-based hydrogels to support the differentiation of white adipose tissue-derived multipotent stem cells (ADMSCs) into lipid-accumulating, UCP1-expressing beige adipose tissue. Subcutaneous implantation of ADMSCs within optimized hydrogels resulted in the establishment of distinct UCP1-expressing implants that successfully attracted host vasculature and persisted for several weeks. Importantly, implant recipients demonstrated elevated core body temperature during cold challenges, enhanced respiration rates, improved glucose homeostasis, and reduced weight gain, demonstrating the therapeutic merit of this highly translatable approach. This novel approach is the first truly clinically translatable system to unlock the therapeutic potential of brown fat-like tissue expansion.
Assuntos
Adipócitos/metabolismo , Tecido Adiposo Marrom/transplante , Canais Iônicos/metabolismo , Proteínas Mitocondriais/metabolismo , Células-Tronco/metabolismo , Termogênese/fisiologia , Alicerces Teciduais , Tecido Adiposo Marrom/metabolismo , Animais , Temperatura Corporal/fisiologia , Adesão Celular/fisiologia , Diferenciação Celular/fisiologia , Temperatura Baixa , Metabolismo Energético/fisiologia , Camundongos , Proteína Desacopladora 1RESUMO
Chiral gold(i) phosphite complexes are readily prepared modularly from 3,3'-bis(triphenylsilyl)-1,1'-bi-2-naphthol. These chiral gold(i) phosphite complexes are very reactive precatalysts for the [4+2] cycloaddition of aryl-substituted 1,6-enynes with enantiomeric ratios ranging from 86 : 14 up to 94 : 6.
RESUMO
A simple and efficient guanidine-catalyzed methodology for the direct preparation of trifluoromethyl-indolyl-phenylethanols in the presence of water is reported. This synthetically viable class of compounds is obtained in excellent yields (up to 98%) through Friedel-Crafts-type alkylation of indoles with aromatic fluoromethyl ketones. Exceptional reaction scope of indoles and alkylating agents is described.
Assuntos
Guanidina/química , Hidrocarbonetos Fluorados/química , Indóis/química , Cetonas/química , Alquilação , Catálise , Técnicas de Química Combinatória , Indóis/síntese química , Estrutura Molecular , Estereoisomerismo , Água/químicaRESUMO
A novel Pd-catalyzed intramolecular allylic alkylation of indoles allows THBCs and THGCs to be effectively synthesized in high yields and excellent enantiomeric excesses (ee up to 97%).