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1.
J Am Chem Soc ; 146(15): 10640-10654, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38568727

RESUMO

Foreign ions as additives are of great significance for realizing excellent control over the morphology of noble metal nanostructures in the state-of-the-art seed-mediated growth method; however, they remain largely unexplored in chiral synthesis. Here, we report on a Cu2+-dominated chiral growth strategy that can direct the growth of concave chiral Au nanoparticles with C3-dominant chiral centers. The introduction of trace amounts of Cu2+ ions in the seed-mediated chiral growth process is found to dominate the chirality transfer from chiral molecules to chiral nanoparticles, leading to the formation of chiral nanoparticles with a concave VC geometry. Both experimental and theoretical results further demonstrate the correlation between the nanoparticle structure and optical chirality for the concave chiral nanoparticle. The Cu2+ ion is found to dominate the chiral growth by selectively activating the deposition of Au atoms along the [110] and [111] directions, facilitating the formation of the concave VC. We further demonstrate that the Cu2+-dominated chiral growth strategy can be employed to generate a variety of concave chiral nanoparticles with enriched geometric chirality and desired chiroptical properties. Concave chiral nanoparticles also exhibit appealing catalytic activity and selectivity toward electrocatalytic oxidation of enantiomers in comparison to helicoidal nanoparticles. The ability to tune the geometric chirality in a controlled manner by simply manipulating the Cu2+ ions as additives opens up a promising strategy for creating chiral nanomaterials with increasing architectural diversity for chirality-dependent optical and catalytic applications.

2.
Small ; 20(23): e2310353, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38150652

RESUMO

Integrating the plasmonic chirality with excellent catalytic activities in plasmonic hybrid nanostructures provides a promising strategy to realize the chiral nanocatalysis toward many chemical reactions. However, the controllable synthesis of catalytically active chiral plasmonic nanoparticles with tailored geometries and compositions remains a significant challenge. Here it is demonstrated that chiral Au-Pd alloy nanorods with tunable optical chirality and catalytically active surfaces can be achieved by a seed-mediated coreduction growth method. Through manipulating the chiral inducers, Au nanorods selectively transform into two different intrinsically chiral Au-Pd alloy nanorods with distinct geometric chirality and tunable optical chirality. By further adjusting several key synthetic parameters, the optical chirality, composition, and geometry of the chiral Au-Pd nanorods are fine-tailored. More importantly, the chiral Au-Pd alloy nanorods exhibit appealing chiral catalytic activities as well as polarization-dependent plasmon-enhanced nanozyme catalytic activity, which has great potential for chiral nanocatalysis and plasmon-induced chiral photochemistry.

3.
Nano Lett ; 23(23): 11376-11384, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38038244

RESUMO

Constructing chiral plexcitonic systems with tunable plasmon-exciton coupling may advance the scientific exploitation of strong light-matter interactions. Because of their intriguing chiroptical properties, chiral plasmonic materials have shown promising applications in photonics, sensing, and biomedicine. However, the strong coupling of chiral plasmonic nanoparticles with excitons remains largely unexplored. Here we demonstrate the construction of a chiral plasmon-exciton system using chiral AuAg nanorods and J aggregates for tuning the plexcitonic optical chirality. Circular dichroism spectroscopy was employed to characterize chiral plasmon-exciton coupling, in which Rabi splitting and anticrossing behaviors were observed, whereas the extinction spectra exhibited less prominent phenomena. By controlling the number of molecular excitons and the energy detuning between plasmons and excitons, we have been able to fine-tune the plexcitonic optical chirality. The ability to fine-tune the plexcitonic optical chirality opens up unique opportunities for exploring chiral light-matter interactions and boosting the development of emerging chiroptical devices.

4.
Small ; 19(30): e2301218, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37029697

RESUMO

Site-selective chiral growth of anisotropic nanoparticles is of great importance to realize the plasmonic nanostructures with delicate geometry and desired optical chirality; however, it remains largely unexplored. This work demonstrates a controlled site-selective chiral growth system based on the seed-mediated growth of anisotropic Au triangular nanoplates. The site-selective chiral growth involves two distinct underlying pathways, faceted growth and island growth, which are interswitchable upon maneuvering the interplay of chiral molecules, surfactants, and reducing agents. The pathway switch governs the geometric and chirality evolution of Au triangular nanoplates, giving rise to tailorable circular dichroism spectra. The ability to tune the optical chirality in a controlled manner by manipulating the site-selective chiral growth pathway opens up a promising strategy for exploiting chiral metamaterials with increasing architectural complexity in chiroptical applications.

5.
Magn Reson Med ; 89(2): 710-720, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36128887

RESUMO

PURPOSE: In current intraoperative MRI (IMRI) methods, an iterative approach is used to aim trajectory guides at intracerebral targets: image MR-visible features, determine current aim by fitting model to image, manipulate device, repeat. Infrequent updates are produced by such methods, compared to rapid optically tracked stereotaxy used in the operating room. Our goal was to develop a real-time interactive IMRI method for aiming. METHODS: The current trajectory was computed from two points along the guide's central axis, rather than by imaging the entire device. These points were determined by correlating one-dimensional spokes from a radial sequence with the known cross-sectional projection of the guide. The real-time platform RTHawk was utilized to control MR sequences and data acquisition. On-screen updates were viewed by the operator while simultaneously manipulating the guide to align it with the planned trajectory. Accuracy was quantitated in a phantom, and in vivo validation was demonstrated in nonhuman primates undergoing preclinical gene ( n = 5 $$ n=5 $$ ) and cell ( n = 4 $$ n=4 $$ ) delivery surgeries. RESULTS: Updates were produced at 5 Hz In 10 phantom experiments at a depth of 48 mm, the cannula tip was placed with radial error of (min, mean, max) = (0.16, 0.29, 0.68) mm. Successful in vivo delivery of payloads to all 14 targets was demonstrated across nine surgeries with depths of (min, mean, max) = (33.3, 37.9, 42.5) mm. CONCLUSION: A real-time interactive update rate was achieved, reducing operator fatigue without compromising accuracy. Qualitative interpretation of images during aiming was rendered unnecessary by objectively computing device alignment.


Assuntos
Neurocirurgia , Animais , Estudos Transversais , Imageamento por Ressonância Magnética/métodos , Imagens de Fantasmas , Imageamento Tridimensional
6.
EMBO Rep ; 21(9): e50000, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32700445

RESUMO

PAX6 is essential for neural retina (NR) and forebrain development but how PAX6 instructs NR versus forebrain specification remains unknown. We found that the paired-less PAX6, PAX6D, is expressed in NR cells during human eye development and along human embryonic stem cell (hESC) specification to retinal cells. hESCs deficient for PAX6D failed to enter NR specification. Induced expression of PAX6D but not PAX6A in a PAX6-null background restored the NR specification capacity. ChIP-Seq, confirmed by functional assays, revealed a set of retinal genes and non-retinal neural genes that are potential targets of PAX6D, including WNT8B. Inhibition of WNTs or knocking down of WNT8B restored the NR specification capacity of neuroepithelia with PAX6D knockout, whereas activation of WNTs blocked NR specification even when PAX6D was induced. Thus, PAX6D specifies neuroepithelia to NR cells via the regulation of WNT8B.


Assuntos
Células-Tronco Embrionárias Humanas , Diferenciação Celular , Proteínas do Olho/genética , Proteínas de Homeodomínio/genética , Humanos , Placa Neural , Retina , Proteínas Wnt/genética
7.
Int J Mol Sci ; 23(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36499548

RESUMO

Construction of the tunable oxygen vacancies (OVs) is widely utilized to accelerate molecular oxygen activation for boosting photocatalytic performance. Herein, the in-situ introduction of OVs on Bi2MoO6 was accomplished using a calcination treatment in an H2/Ar atmosphere. The introduced OVs can not only facilitate carrier separation, but also strengthen the exciton effect, which accelerates singlet oxygen generation through the energy transfer process. Superior carrier separation and abundant singlet oxygen played a crucial role in favoring photocatalytic NaPCP degradation. The optimal BMO-001-300 sample exhibited the fastest NaPCP degradation rate of 0.033 min-1, about 3.8 times higher than that of the pristine Bi2MoO6. NaPCP was effectively degraded and mineralized mainly through dechlorination, dehydroxylation and benzene ring opening. The present work will shed light on the construction and roles of OVs in semiconductor-based photocatalysis and provide a novel insight into ROS-mediated photocatalytic degradation.


Assuntos
Pentaclorofenol , Oxigênio Singlete , Oxigênio , Sódio
8.
Br J Haematol ; 166(2): 279-91, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24750026

RESUMO

Ferritin plays important roles in iron metabolism and controls iron absorption in the intestine. The ferritin subunits ferritin heavy chain (Fth1) and ferritin light chain (Ftl1) are tightly regulated at both the transcriptional and post-transcriptional levels. However, mechanisms of maintaining stable, basal expression of Fth1 are poorly understood. Here, we show that global deletion of Mbd5 in mice induces an iron overload phenotype. Liver and serum iron levels in Mbd5(-/-) mice were 3·2-fold and 1·5-fold higher respectively, than wild-type littermates; moreover, serum ferritin was increased >5-fold in the Mbd5(-/-) mice. Mbd5 encodes a member of the methyl-CpG binding domain family; however, the precise function of this gene is poorly understood. Here, we found that intestinal Fth1 mRNA levels were decreased in Mbd5(-/-) mice. Loss of Fth1 expression in the intestine could lead to iron over-absorption. Furthermore, deleting Mbd5 specifically in the intestine resulted in a phenotype similar to that of conditional deletion of Fth1 mice. An Fth1 promoter-report luciferase assay indicated that overexpression of Mbd5 enhanced Fth1 transcription in a dose-dependent manner. Histone H4 acetylation of the Fth1 promoter was reduced in the intestine of Mbd5(-/-) mice and further analysis showed that histone acetyltransferase KAT2A was essential for MBD5-induced Fth1 transcription.


Assuntos
Apoferritinas/genética , Histona Acetiltransferases/fisiologia , Sobrecarga de Ferro/metabolismo , Ferro/metabolismo , Proteína 2 de Ligação a Metil-CpG/fisiologia , Acetilação , Animais , Apoferritinas/sangue , Metilação de DNA , Deleção de Genes , Regulação da Expressão Gênica , Marcação de Genes , Hemocromatose/sangue , Hemocromatose/genética , Hemocromatose/metabolismo , Hepcidinas/biossíntese , Histonas/metabolismo , Absorção Intestinal/fisiologia , Sobrecarga de Ferro/sangue , Sobrecarga de Ferro/genética , Fígado/metabolismo , Proteína 2 de Ligação a Metil-CpG/deficiência , Proteína 2 de Ligação a Metil-CpG/genética , Camundongos , Camundongos Knockout , Motivos de Nucleotídeos , Fenótipo , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Transcrição Gênica
9.
ACS Nano ; 18(13): 9543-9556, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38518176

RESUMO

Chirality transfer from chiral molecules to chiral nanomaterials represents an important topic for exploring the origin of chirality in many natural and artificial systems. Moreover, developing a promising class of chiral nanomaterials holds great significance for various applications, including sensing, photonics, catalysis, and biomedicine. Here we demonstrate the geometric control and tunable optical chirality of chiral pentatwinned Au nanoparticles with 5-fold rotational symmetry using the seed-mediated chiral growth method. A distinctive growth pathway and optical chirality are observed using pentatwinned decahedra as seeds, in comparison with the single-crystal Au seeds. By employing different peptides as chiral inducers, pentatwinned Au nanoparticles with two distinct geometric chirality (pentagonal nanostars and pentagonal prisms) are obtained. The intriguing formation and evolution of geometric chirality with the twinned structure are analyzed from a crystallographic perspective upon maneuvering the interplay of chiral molecules, surfactants, and reducing agents. Moreover, the interesting effects of the molecular structure of peptides on tuning the geometric chirality of pentatwinned Au nanoparticles are also explored. Finally, we theoretically and experimentally investigate the far-field and near-field optical properties of chiral pentatwinned Au nanoparticles through numerical simulations and single-particle chiroptical measurements. The ability to tune the geometric chirality in a controlled manner represents an important step toward the development of chiral nanomaterials with increasing architectural complexity for chiroptical applications.

10.
Cell Stem Cell ; 31(2): 260-274.e7, 2024 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-38306994

RESUMO

Probing how human neural networks operate is hindered by the lack of reliable human neural tissues amenable to the dynamic functional assessment of neural circuits. We developed a 3D bioprinting platform to assemble tissues with defined human neural cell types in a desired dimension using a commercial bioprinter. The printed neuronal progenitors differentiate into neurons and form functional neural circuits within and between tissue layers with specificity within weeks, evidenced by the cortical-to-striatal projection, spontaneous synaptic currents, and synaptic response to neuronal excitation. Printed astrocyte progenitors develop into mature astrocytes with elaborated processes and form functional neuron-astrocyte networks, indicated by calcium flux and glutamate uptake in response to neuronal excitation under physiological and pathological conditions. These designed human neural tissues will likely be useful for understanding the wiring of human neural networks, modeling pathological processes, and serving as platforms for drug testing.


Assuntos
Bioimpressão , Tecido Nervoso , Humanos , Neurônios/metabolismo , Astrócitos/metabolismo , Engenharia Tecidual
11.
bioRxiv ; 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38328181

RESUMO

Probing how the human neural networks operate is hindered by the lack of reliable human neural tissues amenable for dynamic functional assessment of neural circuits. We developed a 3D bioprinting platform to assemble tissues with defined human neural cell types in a desired dimension using a commercial bioprinter. The printed neuronal progenitors differentiate to neurons and form functional neural circuits in and between tissue layers with specificity within weeks, evidenced by the cortical-to-striatal projection, spontaneous synaptic currents and synaptic response to neuronal excitation. Printed astrocyte progenitors develop into mature astrocytes with elaborated processes and form functional neuron-astrocyte networks, indicated by calcium flux and glutamate uptake in response to neuronal excitation under physiological and pathological conditions. These designed human neural tissues will likely be useful for understanding the wiring of human neural networks, modeling pathological processes, and serving as platforms for drug testing.

12.
Hepatology ; 56(3): 961-71, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22473803

RESUMO

UNLABELLED: The liver is a major site of iron storage where sequestered iron can be actively mobilized for utilization when needed elsewhere in the body. Currently, hepatocyte iron efflux mechanisms and their relationships to macrophage iron recycling during the control of whole-body iron homeostasis are unclear. We hypothesized that the iron exporter, ferroportin1 (Fpn1), is critical for both iron mobilization from hepatocytes and iron recycling from macrophages. To test this, we generated hepatocyte-specific Fpn1 deletion mice (Fpn1(Alb/Alb) ) and mice that lacked Fpn1 in both hepatocytes and macrophages (Fpn1(Alb/Alb;LysM/LysM) ). When fed a standard diet, Fpn1(Alb/Alb) mice showed mild hepatocyte iron retention. However, red blood cell (RBC) counts and hemoglobin (Hb) levels were normal, indicating intact erythropoiesis. When fed an iron-deficient diet, Fpn1(Alb/Alb) mice showed impaired liver iron mobilization and anemia, with much lower RBC and Hb levels than Fpn1(flox/flox) mice on the same diet. Using a strategy where mice were preloaded with differing amounts of dietary iron before iron deprivation, we determined that erythropoiesis in Fpn1(Alb/Alb) and Fpn1(flox/flox) mice depended on the balance between storage iron and iron demands. On a standard diet, Fpn1(Alb/Alb;LysM/LysM) mice displayed substantial iron retention in hepatocytes and macrophages, yet maintained intact erythropoiesis, implying a compensatory role for intestinal iron absorption. In contrast, when Fpn1(Alb/Alb;LysM/LysM) mice were fed an iron-deficient diet, they developed severe iron-deficiency anemia, regardless of their iron storage status. Thus, Fpn1 is critical for both hepatocyte iron mobilization and macrophage iron recycling during conditions of dietary iron deficiency. CONCLUSION: Our data reveal new insights into the relationships between Fpn1-mediated iron mobilization, iron storage, and intestinal iron absorption and how these processes interact to maintain systemic iron homeostasis.


Assuntos
Proteínas de Transporte de Cátions/fisiologia , Hepatócitos/metabolismo , Ferro/metabolismo , Macrófagos/metabolismo , Animais , Homeostase , Camundongos
13.
Blood ; 118(7): 1912-22, 2011 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-21705499

RESUMO

Systemic iron requirements are met predominantly through the recycling of iron from senescent erythrocytes by macrophages, a process in which the iron exporter ferroportin (Fpn1) is considered to be essential. Yet the role of Fpn1 in macrophage iron recycling and whether it influences innate immune responses are poorly understood in vivo. We inactivated Fpn1 in macrophages by crossing Fpn1-floxed animals with macrophage-targeted LysM-Cre or F4/80-Cre transgenic mice. Macrophage Fpn1 deletion mice were overtly normal; however, they displayed a mild anemia and iron accumulation in splenic, hepatic, and bone marrow macrophages when fed a standard diet. Iron loading was exacerbated after the administration of iron dextran or phenylhydrazine. When Fpn1(LysM/LysM) mice were challenged with an iron-deficient diet, they developed a more severe anemia and strikingly higher splenic iron levels than control mice, indicating significantly impaired iron mobilization from macrophages. Because immune responses can be altered by modulating iron status, we also examined the expression of proinflammatory cytokines. We found that expression levels of TNF-α and IL-6 were significantly enhanced in Fpn1(LysM/LysM) macrophages lacking Fpn1. These studies demonstrate that Fpn1 plays important roles in macrophage iron release in vivo and in modulating innate immune responses.


Assuntos
Proteínas de Transporte de Cátions/imunologia , Imunidade Inata , Ferro/metabolismo , Macrófagos/imunologia , Anemia/metabolismo , Anemia/patologia , Animais , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Deleção de Genes , Regulação da Expressão Gênica , Interleucina-6/genética , Interleucina-6/imunologia , Ferro/imunologia , Ferro da Dieta/imunologia , Ferro da Dieta/metabolismo , Fígado/metabolismo , Fígado/patologia , Macrófagos/metabolismo , Camundongos , Camundongos Transgênicos , Baço/metabolismo , Baço/patologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
14.
J Nutr ; 143(7): 1061-6, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23700338

RESUMO

Hepcidin, the pivotal regulator of iron metabolism, plays a critical role in multiple diseases including anemia of chronic disease and hemochromatosis. Recent studies have focused on identifying antagonists of hepcidin. We hypothesized that bioactive extracts from Chinese medicinal plants may be efficacious in the inhibition of expression of the hepcidin-encoding gene (HAMP) product, hepcidin. To test this, we measured the level of hepcidin expression in cultured cells treated with 16 different medicinal plant extracts, all of which are used to treat anemia-related disorders in traditional Chinese medicine. Among the extracts tested, that of Caulis Spatholobi (CS; also called Jixueteng, the stem of Spatholobus suberectus Dunn) showed the most potent inhibitory effect on HAMP expression in the Huh7 cell line and was therefore selected for further mechanistic study. In cells treated with 400 µg/mL of extract, phosphorylated mothers against decapentaplegic homolog proteins 1/5/8 levels were 80% less than those of controls (P < 0.001), and the inhibitory effect on interleukin-6-induced HAMP expression (65% inhibition) was weaker than the strong inhibition on bone morphogenetic protein 6-induced HAMP expression (97% inhibition). Seven-week-old C57BL/6 female mice were fed an AIN-76A diet containing 10.8% dried CS and then analyzed on d 0, 5, 10, or 15. On d 5, there was a 60% decrease in hepatic HAMP expression (P < 0.05), an 18% decrease in hepatic iron concentration, and a 100% increase in serum iron concentration (P < 0.05) compared with the d 0 group. In conclusion, we identify the extract of CS as a novel, potent HAMP expression inhibitor, which may be further modified and optimized to become a dietary supplement or a therapeutic option for the amelioration of hepcidin-overexpression-related diseases, including iron deficiency anemia.


Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Fabaceae/química , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Anemia Ferropriva/tratamento farmacológico , Anemia Ferropriva/genética , Animais , Peptídeos Catiônicos Antimicrobianos/antagonistas & inibidores , Peptídeos Catiônicos Antimicrobianos/metabolismo , Western Blotting , Proteína Morfogenética Óssea 6/farmacologia , Linhagem Celular Tumoral , Feminino , Células Hep G2 , Hepcidinas , Humanos , Interleucina-6/metabolismo , Ferro/sangue , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Análise de Sequência de RNA
15.
Adv Mater ; : e2306297, 2023 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-37572380

RESUMO

Intrinsically chiral plasmonic nanomaterials exhibit intriguing geometry-dependent chiroptical properties, which is due to the combination of plasmonic features with geometric chirality. Thus, chiral plasmonic nanomaterials have become promising candidates for applications in biosensing, asymmetric catalysis, biomedicine, photonics, etc. Recent advances in geometric control and optical tuning of intrinsically chiral plasmonic nanomaterials have further opened up a unique opportunity for their widespread applications in many emerging technological areas. Here, the recent developments in the geometric control of chiral plasmonic nanomaterials are reviewed with special attention given to the quantitative understanding of the chiroptical structure-property relationship. Several important optical spectroscopic tools for characterizing the optical chirality of plasmonic nanomaterials at both ensemble and single-particle levels are also discussed. Three emerging applications of chiral plasmonic nanomaterials, including enantioselective sensing, enantioselective catalysis, and biomedicine, are further highlighted. It is envisioned that these advanced studies in chiral plasmonic nanomaterials will pave the way toward the rational design of chiral nanomaterials with desired optical properties for diverse emerging technological applications.

16.
Nat Biotechnol ; 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37974010

RESUMO

Central norepinephrine (NE) neurons, located mainly in the locus coeruleus (LC), are implicated in diverse psychiatric and neurodegenerative diseases and are an emerging target for drug discovery. To facilitate their study, we developed a method to generate 40-60% human LC-NE neurons from human pluripotent stem cells. The approach depends on our identification of ACTIVIN A in regulating LC-NE transcription factors in dorsal rhombomere 1 (r1) progenitors. In vitro generated human LC-NE neurons display extensive axonal arborization; release and uptake NE; and exhibit pacemaker activity, calcium oscillation and chemoreceptor activity in response to CO2. Single-nucleus RNA sequencing (snRNA-seq) analysis at multiple timepoints confirmed NE cell identity and revealed the differentiation trajectory from hindbrain progenitors to NE neurons via an ASCL1-expressing precursor stage. LC-NE neurons engineered with an NE sensor reliably reported extracellular levels of NE. The availability of functional human LC-NE neurons enables investigation of their roles in psychiatric and neurodegenerative diseases and provides a tool for therapeutics development.

17.
Haematologica ; 97(12): 1826-35, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22689674

RESUMO

BACKGROUND: Iron and its homeostasis are intimately related to inflammatory responses, but the underlying molecular mechanisms are poorly understood. We investigated the role of Steap3 in regulating iron homeostasis in macrophages, and the effects of Steap3 depletion on host inflammatory responses. DESIGN AND METHODS: We analyzed bone marrow-derived macrophages and primary cultured hepatocytes from Steap3(-/-) mouse models to investigate the roles of Steap3 in coordinately regulating iron homeostasis and inflammatory responses. First, we examined iron distribution and iron status in cells deficient in Steap3, as well as the requirement for the Steap3 gene during inflammatory responses. Secondly, we analyzed the regulation of Steap3 expression by inflammatory stimuli and thus, the influence of these stimuli on iron distribution and homeostasis. RESULTS: We found that Steap3 mRNA was expressed at high levels in macrophages and hepatocytes. Steap3 deficiency led to impaired iron homeostasis, causing abnormal iron distribution and a decreased availability of cytosolic iron in macrophages. Among STEAP family members, Steap3 mRNA was uniquely down-regulated in macrophages stimulated by lipopolysaccharides. To determine whether Steap3 regulated iron homeostasis during inflammatory stress, we treated Steap3(-/-) mice with lipopolysaccharide, which produced greater iron accumulation in the vital tissues of these mice compared to in the tissues of wild-type controls. Furthermore, Steap3 depletion led to impaired induction of interferon-ß, monocyte chemoattractant protein-5, and interferon induced protein-10 in macrophages via the TLR4-mediated signaling pathway. CONCLUSIONS: Steap3 is important in regulating both iron homeostasis and TLR4-mediated inflammatory responses in macrophages. Steap3 deficiency causes abnormal iron status and homeostasis, which leads to impaired TLR4-mediated inflammatory responses in macrophages. Following inflammatory stimuli, Steap3 depletion causes dysregulated iron sequestration and distribution. Our results provide important insights into the function of Steap3 as a coordinate regulator of both iron homeostasis and innate immunity.


Assuntos
Homeostase , Inflamação/etiologia , Ferro/metabolismo , Macrófagos/metabolismo , Proteínas de Membrana/fisiologia , Animais , Western Blotting , Proteínas de Ciclo Celular , Proliferação de Células/efeitos dos fármacos , Hepatócitos/citologia , Hepatócitos/metabolismo , Inflamação/metabolismo , Inflamação/patologia , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Camundongos , Camundongos Knockout , Oxirredutases , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo
18.
ACS Nano ; 16(11): 19174-19186, 2022 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-36251931

RESUMO

Plasmonic nanoparticles with an intrinsic chiral structure have emerged as a promising chiral platform for applications in biosensing, medicine, catalysis, separation, and photonics. Quantitative understanding of the correlation between nanoparticle structure and optical chirality becomes increasingly important but still represents a significantly challenging task. Here we demonstrate that tunable signal reversal of circular dichroism in the seed-mediated chiral growth of plasmonic nanoparticles can be achieved through the hybridization of bichiral centers without inverting the geometric chirality. Both experimental and theoretical results demonstrated the opposite sign of circular dichroism of two different bichiral geometries. Chiral molecules were found to not only contribute to the chirality transfer from molecules to nanoparticles but also manipulate the structural evolution of nanoparticles that synergistically drive the formation of two different chiral centers. By deliberately adjusting the concentration of chiral molecules and other synthetic parameters, such as the reducing agent concentration, the capping surfactant concentration, and the amount of Au precursor, we have been able to fine-tune the circular dichroism reversal of bichiral Au nanoparticles. We further demonstrate that the structure of chiral molecules and the crystal structure of Au seeds play crucial roles in the formation of Au nanoparticles with bichiral centers. The insights gained from this work not only shed light on the underlying mechanisms dictating the intriguing geometric and chirality evolution of bichiral plasmonic nanoparticles but also provide an important knowledge framework that guides the rational design of bichiral plasmonic nanostructures toward chiroptical applications.


Assuntos
Nanopartículas Metálicas , Nanoestruturas , Dicroísmo Circular , Ouro/química , Nanopartículas Metálicas/química , Nanoestruturas/química , Estereoisomerismo
19.
Stem Cell Reports ; 17(6): 1366-1379, 2022 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-35623352

RESUMO

Individuals with Down syndrome (DS; Ts21), the most common genetic cause of intellectual disability, have smaller brains that reflect fewer neurons at pre- and post-natal stages, implicating impaired neurogenesis during development. Our stereological analysis of adult DS cortex indicates a reduction of calretinin-expressing interneurons. Using Ts21 human induced pluripotent stem cells (iPSCs) and isogenic controls, we find that Ts21 progenitors generate fewer COUP-TFII+ progenitors with reduced proliferation. Single-cell RNA sequencing of Ts21 progenitors confirms the altered specification of progenitor subpopulations and identifies reduced WNT signaling. Activation of WNT signaling partially restores the COUP-TFII+ progenitor population in Ts21, suggesting that altered WNT signaling contributes to the defective development of cortical interneurons in DS.


Assuntos
Síndrome de Down , Células-Tronco Pluripotentes Induzidas , Adulto , Síndrome de Down/genética , Humanos , Interneurônios , Neurogênese/fisiologia , Neurônios , Trissomia
20.
Nat Med ; 27(4): 632-639, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33649496

RESUMO

Degeneration of dopamine (DA) neurons in the midbrain underlies the pathogenesis of Parkinson's disease (PD). Supplement of DA via L-DOPA alleviates motor symptoms but does not prevent the progressive loss of DA neurons. A large body of experimental studies, including those in nonhuman primates, demonstrates that transplantation of fetal mesencephalic tissues improves motor symptoms in animals, which culminated in open-label and double-blinded clinical trials of fetal tissue transplantation for PD1. Unfortunately, the outcomes are mixed, primarily due to the undefined and unstandardized donor tissues1,2. Generation of induced pluripotent stem cells enables standardized and autologous transplantation therapy for PD. However, its efficacy, especially in primates, remains unclear. Here we show that over a 2-year period without immunosuppression, PD monkeys receiving autologous, but not allogenic, transplantation exhibited recovery from motor and depressive signs. These behavioral improvements were accompanied by robust grafts with extensive DA neuron axon growth as well as strong DA activity in positron emission tomography (PET). Mathematical modeling reveals correlations between the number of surviving DA neurons with PET signal intensity and behavior recovery regardless autologous or allogeneic transplant, suggesting a predictive power of PET and motor behaviors for surviving DA neuron number.


Assuntos
Comportamento Animal , Depressão/complicações , Transplante de Tecido Fetal , Atividade Motora , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia , Animais , Dopamina/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Inflamação/patologia , Modelos Lineares , Macaca mulatta , Masculino , Mesencéfalo/transplante , Camundongos , Doença de Parkinson/complicações , Tomografia por Emissão de Pósitrons , Transplante Autólogo , Transplante Homólogo , Tirosina 3-Mono-Oxigenase/metabolismo
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