Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.137
Filtrar
1.
Nature ; 576(7785): 46-47, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31792417
2.
J Biomed Nanotechnol ; 15(11): 2179-2192, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31847932

RESUMO

Until now, there is no effective method for tracking transplanted stem cells in human. Ruicun (RC) is a new ultra-small SPIONs agent that has been approved by China Food and Drug Administration for iron supplementation but not as a stem cell tracer in clinic. In this study, we demonstrated magnetic resonance imaging-based tracking of RC-labeled human umbilical cord derived mesenchymal stem cells (MSCs) transplanted to locally injured site of rat spinal cords. We then comprehensively evaluated the safety and quality of the RC-labeled MSCs under good manufacturing practicecompliant conditions, to investigate the feasibility of SPIONs for inner tracking in stem cell-based therapy (SCT). Our results showed that RC labeling at appropriate dose (200 µg/mL) did not have evident impacts on characteristics of MSCs in vitro, demonstrating safety, non-carcinogenesis, and non-tissue inflammation in vivo. The systematic assessments of intracellular biocompatibility indicated that the RC labeled MSCs met with mandatory requirements and standards for law-regulation systems regarding SCT, facilitating translation of cell-tracking technologies to clinical trials.


Assuntos
Nanopartículas de Magnetita , Cordão Umbilical , Animais , Rastreamento de Células , Humanos , Imagem por Ressonância Magnética , Transplante de Células-Tronco Mesenquimais , Mesoderma , Ratos
3.
J Biomed Nanotechnol ; 15(11): 2271-2280, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31847941

RESUMO

Stem-cell-based therapy has attracted considerable attention due to the significant benefits to patients experiencing a wide range of diseases and injuries. However, their underlying mechanism of action is not completely understood. One main reason is the lack of imaging tools for real-time tracking of deep-seated transplanted stem cells. For the present study, we exploited a lipid poly(lactic-co-glycolic acid) nanobubble (LPN) probe with nanoscale size, good compatibility, and strong contrast-enhanced ultrasound signals. Due to the nanoscale particle size, cellular labeling of mesenchymal stem cells can be achieved via incubation with LPNs. Significantly enhanced ultrasound images of these labeled stem cells were obtained in vitro and in vivo. More importantly, the labeled stem cells could be tracked by ultrasound imaging for up to 5 days. Additional evaluation found that the in vivo detection limit achieved 2,000 labeled stem cells in the subcutaneous tissues of living mice. Our study presents a strategy to achieve real-time ultrasound imaging tracking, paving the way for an investigation on the underlying mechanism and future clinical application of stem cell therapy.


Assuntos
Células-Tronco Mesenquimais , Animais , Rastreamento de Células , Glicóis , Lipídeos , Camundongos , Nanotubos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Células-Tronco
4.
Nat Cell Biol ; 21(11): 1309-1320, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31685996

RESUMO

With ageing, intrinsic haematopoietic stem cell (HSC) activity decreases, resulting in impaired tissue homeostasis, reduced engraftment following transplantation and increased susceptibility to diseases. However, whether ageing also affects the HSC niche, and thereby impairs its capacity to support HSC function, is still widely debated. Here, by using in-vivo long-term label-retention assays we demonstrate that aged label-retaining HSCs, which are, in old mice, the most quiescent HSC subpopulation with the highest regenerative capacity and cellular polarity, reside predominantly in perisinusoidal niches. Furthermore, we demonstrate that sinusoidal niches are uniquely preserved in shape, morphology and number on ageing. Finally, we show that myeloablative chemotherapy can selectively disrupt aged sinusoidal niches in the long term, which is linked to the lack of recovery of endothelial Jag2 at sinusoids. Overall, our data characterize the functional alterations of the aged HSC niche and unveil that perisinusoidal niches are uniquely preserved and thereby protect HSCs from ageing.


Assuntos
Envelhecimento/genética , Capilares/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Homeostase/genética , Nicho de Células-Tronco/genética , Envelhecimento/metabolismo , Animais , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Capilares/citologia , Capilares/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Polaridade Celular/efeitos dos fármacos , Rastreamento de Células/métodos , Doxiciclina/farmacologia , Fluoruracila/farmacologia , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Histonas/genética , Histonas/metabolismo , Homeostase/efeitos dos fármacos , Proteína Jagged-2/genética , Proteína Jagged-2/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Agonistas Mieloablativos/farmacologia , Nicho de Células-Tronco/efeitos dos fármacos
5.
Nat Cell Biol ; 21(11): 1370-1381, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31685997

RESUMO

Cell migration is hypothesized to involve a cycle of behaviours beginning with leading edge extension. However, recent evidence suggests that the leading edge may be dispensable for migration, raising the question of what actually controls cell directionality. Here, we exploit the embryonic migration of Drosophila macrophages to bridge the different temporal scales of the behaviours controlling motility. This approach reveals that edge fluctuations during random motility are not persistent and are weakly correlated with motion. In contrast, flow of the actin network behind the leading edge is highly persistent. Quantification of actin flow structure during migration reveals a stable organization and asymmetry in the cell-wide flowfield that strongly correlates with cell directionality. This organization is regulated by a gradient of actin network compression and destruction, which is controlled by myosin contraction and cofilin-mediated disassembly. It is this stable actin-flow polarity, which integrates rapid fluctuations of the leading edge, that controls inherent cellular persistence.


Assuntos
Actinas/genética , Movimento Celular/genética , Drosophila melanogaster/embriologia , Mecanotransdução Celular , Peixe-Zebra/embriologia , Actinas/metabolismo , Animais , Polaridade Celular , Rastreamento de Células , Cofilina 1/genética , Cofilina 1/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Hemócitos/citologia , Hemócitos/metabolismo , Queratinócitos/citologia , Queratinócitos/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Miosinas/genética , Miosinas/metabolismo , Cultura Primária de Células , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
6.
Mar Biotechnol (NY) ; 21(5): 671-682, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31502176

RESUMO

Primordial germ cells (PGCs) as the precursors of germ cells are responsible for transmitting genetic information to the next generation. Visualization of teleost PGCs in vivo is essential to research the origination and development of germ cells and facilitate further manipulation on PGCs isolation, cryopreservation, and surrogate breeding. In this study, artificially synthesized mRNAs constructed by fusing fluorescent protein coding region to the 3' untranslated region (3'UTR) of nanos3 or vasa (mCherry-Smnanos3 3'UTR or mCherry-Smvasa 3'UTR mRNA) were injected into turbot (Scophthalmus maximus) fertilized eggs for tracing PGCs. The results demonstrated that the fluorescent PGCs differentiated from somatic cells and aligned on both sides of the trunk at the early segmentation period, then migrated and located at the dorsal part of the gut where the gonad would form. In the same way, we also found that the zebrafish (Danio rerio) vasa 3'UTR could trace turbot PGCs, while the vasa 3'UTR s of marine medaka (Oryzias melastigma) and red seabream (Pagrus major) failed, although they could label the marine medaka PGCs. In addition, through comparative analysis, we discovered that some potential sequence elements in the3 'UTRs of nanos3 and vasa, such as GCACs, 62-bp U-rich regions and nucleotide 187-218 regions might be involved in PGCs stabilization. The results of this study provided an efficient, rapid, and specific non-transgenic approach for visualizing PGCs of economical marine fish in vivo.


Assuntos
Rastreamento de Células/métodos , Proteínas de Peixes/genética , Linguados/genética , Células Germinativas/metabolismo , Proteínas Recombinantes de Fusão/genética , Peixe-Zebra/genética , Regiões 3' não Traduzidas , Animais , Sequência de Bases , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Proteínas de Peixes/metabolismo , Linguados/crescimento & desenvolvimento , Linguados/metabolismo , Genes Reporter , Células Germinativas/citologia , Células Germinativas/crescimento & desenvolvimento , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Microinjeções , Conformação de Ácido Nucleico , Oryzias/genética , Oryzias/crescimento & desenvolvimento , Oryzias/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Especificidade da Espécie , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Zigoto
7.
8.
Nature ; 572(7771): 670-675, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31391580

RESUMO

Macrophages are considered to contribute to chronic inflammatory diseases such as rheumatoid arthritis1. However, both the exact origin and the role of macrophages in inflammatory joint disease remain unclear. Here we use fate-mapping approaches in conjunction with three-dimensional light-sheet fluorescence microscopy and single-cell RNA sequencing to perform a comprehensive spatiotemporal analysis of the composition, origin and differentiation of subsets of macrophages within healthy and inflamed joints, and study the roles of these macrophages during arthritis. We find that dynamic membrane-like structures, consisting of a distinct population of CX3CR1+ tissue-resident macrophages, form an internal immunological barrier at the synovial lining and physically seclude the joint. These barrier-forming macrophages display features that are otherwise typical of epithelial cells, and maintain their numbers through a pool of locally proliferating CX3CR1- mononuclear cells that are embedded into the synovial tissue. Unlike recruited monocyte-derived macrophages, which actively contribute to joint inflammation, these epithelial-like CX3CR1+ lining macrophages restrict the inflammatory reaction by providing a tight-junction-mediated shield for intra-articular structures. Our data reveal an unexpected functional diversification among synovial macrophages and have important implications for the general role of macrophages in health and disease.


Assuntos
Articulações/citologia , Macrófagos/citologia , Macrófagos/fisiologia , Membrana Sinovial/citologia , Sinoviócitos/citologia , Sinoviócitos/fisiologia , Junções Íntimas/fisiologia , Animais , Artrite/imunologia , Artrite/patologia , Receptor 1 de Quimiocina CX3C/análise , Receptor 1 de Quimiocina CX3C/metabolismo , Rastreamento de Células , Feminino , Perfilação da Expressão Gênica , Humanos , Inflamação/imunologia , Inflamação/patologia , Articulações/patologia , Macrófagos/classificação , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Análise de Componente Principal , Análise de Célula Única , Sinoviócitos/classificação , Sinoviócitos/metabolismo , Transcriptoma/genética
9.
ACS Appl Mater Interfaces ; 11(36): 32647-32658, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31381288

RESUMO

Red-emitting carbon dots (CDs) have attracted tremendous attention due to their wide applications in areas including imaging, sensing, drug delivery, and cancer therapy. However, it is still highly challenging for red-emitting CDs to simultaneously achieve high quantum yields (QYs), nucleus targeting, and super-resolution fluorescence imaging (especially the stimulated emission depletion (STED) imaging). Here, it is found that the addition of varied metal ions during the hydrothermal treatment of p-phenylenediamine (pPDA) leads to the formation of fluorescent CDs with emission wavelengths up to 700 nm. Strikingly, although metal ions play a crucial role in the synthesis of CDs with varied QYs, they are absent in the formed CDs, that is, the obtained CDs are metal-free, and the metal ions play a role similar to a "catalyst" during the CD formation. Besides, using pPDA and nickel ions (Ni2+) as raw materials, we prepare Ni-pPCDs which have the highest QY and exhibit various excellent fluorescence properties including excitation-independent emission (at ∼605 nm), good photostability, polarity sensitivity, and ribonucleic acid responsiveness. In vitro and in vivo experiments demonstrate that Ni-pPCDs are highly biocompatible and can realize real-time, wash-free, and high-resolution imaging of cell nuclei and high-contrast imaging of tumor-bearing mice and zebrafish. In summary, the present work may hold great promise in the synthesis and applications of red emissive CDs.


Assuntos
Carbono/química , Nucléolo Celular/metabolismo , Rastreamento de Células , Imagem Molecular , Pontos Quânticos/química , Células A549 , Animais , DNA/metabolismo , Endocitose , Humanos , Camundongos , Níquel/química , Fenilenodiaminas/química , Espectroscopia Fotoeletrônica , Pontos Quânticos/ultraestrutura , RNA/metabolismo , Espectrometria de Fluorescência , Peixe-Zebra
10.
Chemistry ; 25(55): 12712-12718, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31433877

RESUMO

Arylated cyclobutanes were accessed by a versatile palladium-catalyzed secondary C(sp3 )-H activation, exploiting chelation assistance by modular triazoles. The C-H arylation led to cyclobutane natural product derivatives in a highly regioselective fashion, setting the stage for the easy access to novel fluorogenic boron-dipyrrin (BODIPY)-labeled probes for live-cell imaging.


Assuntos
Rastreamento de Células/métodos , Ciclobutanos/química , Imagem Óptica/métodos , Triazóis/química , Boro , Compostos de Boro , Catálise , Quelantes/química , Estrutura Molecular , Paládio/química
11.
Nat Protoc ; 14(9): 2648-2671, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31420599

RESUMO

Lineage tracing is a powerful tool that can be used to uncover cell fates. Here, we describe a novel method for the quantitative analysis of clonal dynamics in grafted cancer tissues. The protocol involves the preparation and validation of cells for lineage tracing, establishment of grafts and label induction, analysis of clone-size distribution and fitting of the experimental data to a mathematical tumor growth model. In contrast to other lineage-tracing strategies, the method described here assesses stem cell functionality and infers tumor expansion dynamics independently of molecular markers such as putative cancer stem cell (CSC)-specific genes. The experimental system and analytical framework presented can be used to quantify clonal advantages that specific mutations provide, in both the absence and presence of (targeted) therapeutic agents. This protocol typically takes ~20 weeks to complete from cell line selection to inference of growth dynamics, depending on the grafted cancer growth rate.


Assuntos
Linhagem da Célula , Rastreamento de Células/métodos , Células-Tronco Neoplásicas , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Linhagem da Célula/efeitos dos fármacos , Linhagem da Célula/fisiologia , Xenoenxertos , Humanos , Camundongos , Neoplasias/fisiopatologia , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/fisiologia
12.
Nat Commun ; 10(1): 3400, 2019 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363088

RESUMO

Single-molecule localization microscopy (SMLM) is a rapidly evolving technique to resolve subcellular structures and single-molecule dynamics at the nanoscale. Here, we employ conventional BODIPY conjugates for live-cell SMLM via their previously reported red-shifted ground-state dimers (DII), which transiently form through bi-molecular encounters and emit bright single-molecule fluorescence. We employ the versatility of DII-state SMLM to resolve the nanoscopic spatial regulation and dynamics of single fatty acid analogs (FAas) and lipid droplets (LDs) in living yeast and mammalian cells with two colors. In fed cells, FAas localize to the endoplasmic reticulum and LDs of ~125 nm diameter. Upon fasting, however, FAas form dense, non-LD clusters of ~100 nm diameter at the plasma membrane and transition from free diffusion to confined immobilization. Our reported SMLM capability of conventional BODIPY conjugates is further demonstrated by imaging lysosomes in mammalian cells and enables simple and versatile live-cell imaging of sub-cellular structures at the nanoscale.


Assuntos
Compostos de Boro/química , Rastreamento de Células/métodos , Corantes Fluorescentes/química , Imagem Individual de Molécula/métodos , Linhagem Celular Tumoral , Rastreamento de Células/instrumentação , Células/química , Células/citologia , Células/metabolismo , Retículo Endoplasmático/química , Retículo Endoplasmático/metabolismo , Humanos , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Imagem Individual de Molécula/instrumentação
13.
Nat Methods ; 16(8): 707-710, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31285624

RESUMO

Green-to-red photoconvertible fluorescent proteins repeatedly enter dark states, causing interrupted tracks in single-particle-tracking localization microscopy (sptPALM). We identified a long-lived dark state in photoconverted mEos4b that results from isomerization of the chromophore and efficiently absorbs cyan light. Addition of weak 488-nm light swiftly reverts this dark state to the fluorescent state. This strategy largely eliminates slow blinking and enables the recording of longer tracks in sptPALM with minimum effort.


Assuntos
Antígeno B7-2/análise , Rastreamento de Células/métodos , Proteínas Luminescentes/análise , Microscopia de Fluorescência/métodos , Animais , Antígeno B7-2/genética , Células COS , Cristalografia por Raios X , Células HeLa , Humanos , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Mutação , Processos Fotoquímicos , Conformação Proteica
14.
Future Med Chem ; 11(10): 1157-1175, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31280670

RESUMO

MRI has been recognized as one of the most applied medical imaging techniques in clinical practice. However, the presence of background signal coming from water protons in surrounding tissues makes sometimes the visualization of local contrast agents difficult. To remedy this, fluorine has been introduced as a reliable perspective, thanks to its magnetic properties being relatively close to those of protons. In this review, we aim to give an overall description of fluorine incorporation in contrast agents for MRI. The different kinds of fluorinated probes such as perfluorocarbons, fluorinated dendrimers, polymers and paramagnetic probes will be described, as will their imaging applications such as chemical exchange saturation transfer (CEST) imaging, physico-chemical changes detection, drug delivery, cell tracking and inflammation or tumors detection.


Assuntos
Meios de Contraste/química , Flúor/química , Imagem por Ressonância Magnética/métodos , Animais , Rastreamento de Células/métodos , Dendrímeros/química , Sistemas de Liberação de Medicamentos/métodos , Fluorcarbonetos/química , Gadolínio/química , Halogenação , Humanos , Neoplasias/diagnóstico por imagem , Polímeros/química
16.
Int J Mol Sci ; 20(14)2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31340593

RESUMO

Normothermic machine perfusion (NMP) of kidneys offers the opportunity to perform active interventions, such as the addition of mesenchymal stromal cells (MSCs), to an isolated organ prior to transplantation. The purpose of this study was to determine whether administering MSCs to kidneys during NMP is feasible, what the effect of NMP is on MSCs and whether intact MSCs are retained in the kidney and to which structures they home. Viable porcine kidneys were obtained from a slaughterhouse. Kidneys were machine perfused during 7 h at 37 °C. After 1 h of perfusion either 0, 105, 106 or 107 human adipose tissue derived MSCs were added. Additional ex vivo perfusions were conducted with fluorescent pre-labelled bone-marrow derived MSCs to assess localisation and survival of MSCs during NMP. After NMP, intact MSCs were detected by immunohistochemistry in the lumen of glomerular capillaries, but only in the 107 MSC group. The experiments with fluorescent pre-labelled MSCs showed that only a minority of glomeruli were positive for infused MSCs and most of these glomeruli contained multiple MSCs. Flow cytometry showed that the number of infused MSCs in the perfusion circuit steeply declined during NMP to approximately 10%. In conclusion, the number of circulating MSCs in the perfusate decreases rapidly in time and after NMP only a small portion of the MSCs are intact and these appear to be clustered in a minority of glomeruli.


Assuntos
Rastreamento de Células/métodos , Glomérulos Renais/ultraestrutura , Transplante de Rim , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/citologia , Perfusão/métodos , Adipócitos/citologia , Adipócitos/fisiologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/fisiologia , Diferenciação Celular , Corantes Fluorescentes/metabolismo , Humanos , Glomérulos Renais/cirurgia , Transplante de Células-Tronco Mesenquimais/instrumentação , Células-Tronco Mesenquimais/fisiologia , Microscopia de Fluorescência , Preservação de Órgãos/métodos , Compostos Orgânicos/metabolismo , Perfusão/instrumentação , Suínos , Temperatura Ambiente , Transplante Heterólogo
17.
Rapid Commun Mass Spectrom ; 33(20): 1565-1570, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31222818

RESUMO

RATIONALE: Mesenchymal stem cells (MSCs) are widely used in regenerative medicine research. Evaluating the biodistribution of MSCs is important for determining whether the cells have reached the target tissue, and the time that the stem cells reside in each area is required to estimate the duration of efficacy. METHODS: A laser ablation inductively coupled plasma imaging mass spectrometry (LAICP-IMS) method was developed for highly sensitive and quantitative surface analysis of metal elements for solid samples. We evaluated the usefulness of a cell-tracking system with LAICP-IMS to investigate the biodistribution of mouse mesenchymal stem cells (mMSCs) labeled with the natural composition of chromium (Cr) in mice. To prepare the dosing solution, mMSCs were incubated with both Na2 CrO4 and fluorescent labeling solutions. The concentration of the cells was adjusted by vehicle solution at 2.0 to 2.5 × 107 cells/mL, and the dosing suspension of mMSCs was administered by intramuscular or intravenous injection to the mice. RESULTS: Thigh muscle sections after intramuscular injection of chromium- and fluorescence-labeled mMSCs were analyzed by LAICP-IMS and fluorescence microscopy, respectively. 52 Cr mass spectrometry and fluorescence signals were detected in the same thigh muscle sections after administration of mMSCs. A half-body section was also analyzed by LAICP-IMS. 52 Cr signals were mainly detected in the lungs. CONCLUSIONS: The 52 Cr signals were observed in sections through the thigh muscle and half body after intramuscular and intravenous administration, respectively, of Cr-labeled mMSCs to mice. Our results suggest that LAICP-IMS is a sensitive and useful technique to evaluate biodistribution in cell therapy research.


Assuntos
Rastreamento de Células/métodos , Cromo/análise , Terapia a Laser/métodos , Espectrometria de Massas/métodos , Células-Tronco Mesenquimais/química , Animais , Células Cultivadas , Cromo/metabolismo , Masculino , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Distribuição Tecidual
18.
Mater Sci Eng C Mater Biol Appl ; 102: 427-436, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147013

RESUMO

Multimodal long-term imaging probes with capability of extracting complementary information are highly important in biomedical engineering for disease diagnosis and monitoring of therapeutics distribution. However, most of the theranostics probes used are transient and have inherent problem of toxicity mostly related to generation of free radicals. In current study, a simple microwave assisted synthesis of multimodal imaging nanoprobe (T1 contrast in MR/fluorescence) is reported via doping carbon quantum dots into manganese oxide nanoparticles. The nanostructures were characterized by US-Vis spectroscopy, fluorescence spectroscopy, FTIR, Raman spectroscopy, TEM, XRD, AFM and XPS. The average particle size was observed to be around 20-40 nm with a height of 7-9 nm and approximate quantum yield of 0.23. The nanostructures were useful for bio imaging and cell tracking via fluorescence microscopy up to 12 generations with nominal cytotoxicity. The material was capable of scavenging free radicals from cellular microenvironment and downregulate gene expression of free radical scavenging enzymes. The material has significant relaxivity (r1) value of 3.98 mM-1.sec-1 at 1.5 T. It was also observed to create significant contrast with high circulation time (30 min) and renal clearance property. The histological analysis of kidney and liver sections were observed to have no significant toxicity from the nanostructure.


Assuntos
Rastreamento de Células , Imagem por Ressonância Magnética , Compostos de Manganês/química , Nanocompostos/química , Óxidos/química , Pontos Quânticos/química , Espécies Reativas de Oxigênio/metabolismo , Animais , DNA/metabolismo , Fluorescência , Hemólise , Humanos , Rim/citologia , Fígado/citologia , Camundongos , Nanocompostos/ultraestrutura , Espectroscopia Fotoeletrônica , Ratos
19.
Neuroimage ; 199: 153-159, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31152841

RESUMO

The subventricular zone (SVZ) is a neurogenic niche in the mammalian brain, giving rise to migratory neural progenitor cells (NPC). In rodents, it is well-established that neurogenesis decreases with aging. MRI-based cell tracking has been used to measure various aspects of neurogenesis and NPC migration in rodents, yet it has not yet been validated in the context of age-related decrease in neurogenesis. This validation is critical to using these MRI techniques to study changes in neurogenesis that arise in diseases prevalent in aging populations and their combination with advanced cellular therapeutic approaches aiming to combat neurodegeneration. As such, in this work we used MRI-based cell tracking to measure endogenous neurogenesis and cell migration from the SVZ along the rostral migratory stream to the olfactory bulb, for 12 days duration, in rats aged 9 weeks to 2 years old. To enable the specific detection of NPCs by MRI, we injected micron sized particles of iron oxide (MPIOs) into the lateral ventricle to endogenously label cells within the SVZ, which then appeared as hypo-intensive spots within MR images. In vivo MRI data showed that the rate of NPC migration was significantly different between all ages examined, with decreases in the distance traveled and migration rate as age progressed. The total number of MPIO-labeled cells within the olfactory bulb on day 12, was significantly decreased when compared across ages in ex vivo high-resolution scans. We also demonstrate for the first-time, provocative preliminary data suggesting age-dependent MPIO uptake within the dentate gyrus (DG) as well. Histology to identify doublecortin-positive NPCs, verified the decrease in cell labeling as a function of aging, for both regions. The dramatic reduction of NPC labeling within the SVZ observed with MRI, validates the sensitivity of MRI-based cell tracking to neurogenic potential and demonstrates the importance of understanding the impact of age on the relationship of NPC and disease.


Assuntos
Envelhecimento , Rastreamento de Células/métodos , Giro Denteado/diagnóstico por imagem , Ventrículos Laterais/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Células-Tronco Neurais/fisiologia , Animais , Movimento Celular/fisiologia , Compostos Férricos , Ratos , Ratos Endogâmicos F344 , Coloração e Rotulagem
20.
PLoS One ; 14(6): e0217842, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31170273

RESUMO

Magnetic resonance imaging (MRI) is a non-invasive imaging modality used in longitudinal cell tracking. Previous studies suggest that MagA, a putative iron transport protein from magnetotactic bacteria, is a useful gene-based magnetic resonance contrast agent. Hemagglutinin-tagged MagA was stably expressed in undifferentiated embryonic mouse teratocarcinoma, multipotent P19 cells to provide a suitable model for tracking these cells during differentiation. Western blot and immunocytochemistry confirmed the expression and membrane localization of MagA in P19 cells. Surprisingly, elemental iron analysis using inductively-coupled plasma mass spectrometry revealed significant iron uptake in both parental and MagA-expressing P19 cells, cultured in the presence of iron-supplemented medium. Withdrawal of this extracellular iron supplement revealed unexpected iron export activity in P19 cells, which MagA expression attenuated. The influence of iron supplementation on parental and MagA-expressing cells was not reflected by longitudinal relaxation rates. Measurement of transverse relaxation rates (R2* and R2) reflected changes in total cellular iron content but did not clearly distinguish MagA-expressing cells from the parental cell type, despite significant differences in the uptake and retention of total cellular iron. Unlike other cell types, the reversible component R2' (R2* ‒ R2) provided only a moderately strong correlation to amount of cellular iron, normalized to amount of protein. This is the first report to characterize MagA expression in a previously unrecognized iron exporting cell type. The interplay between contrast gene expression and systemic iron metabolism substantiates the potential for diverting cellular iron toward the formation of a novel iron compartment, however rudimentary when using a single magnetotactic bacterial gene expression system like magA. Since relatively few mammalian cells export iron, the P19 cell line provides a tractable model of ferroportin activity, suitable for magnetic resonance analysis of key iron-handling activities and their influence on gene-based MRI contrast.


Assuntos
Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Ferro/metabolismo , Animais , Linhagem Celular Tumoral , Rastreamento de Células/métodos , Meios de Contraste/metabolismo , Expressão Gênica/genética , Genes Reporter/genética , Imagem por Ressonância Magnética/métodos , Camundongos , Células-Tronco Multipotentes/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA