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1.
Nature ; 596(7870): 114-118, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34262174

RESUMEN

Pathogenic fungi reside in the intestinal microbiota but rarely cause disease. Little is known about the interactions between fungi and the immune system that promote commensalism. Here we investigate the role of adaptive immunity in promoting mutual interactions between fungi and host. We find that potentially pathogenic Candida species induce and are targeted by intestinal immunoglobulin A (IgA) responses. Focused studies on Candida albicans reveal that the pathogenic hyphal morphotype, which is specialized for adhesion and invasion, is preferentially targeted and suppressed by intestinal IgA responses. IgA from mice and humans directly targets hyphal-enriched cell-surface adhesins. Although typically required for pathogenesis, C. albicans hyphae are less fit for gut colonization1,2 and we show that immune selection against hyphae improves the competitive fitness of C. albicans. C. albicans exacerbates intestinal colitis3 and we demonstrate that hyphae and an IgA-targeted adhesin exacerbate intestinal damage. Finally, using a clinically relevant vaccine to induce an adhesin-specific immune response protects mice from C. albicans-associated damage during colitis. Together, our findings show that adaptive immunity suppresses harmful fungal effectors, with benefits to both C. albicans and its host. Thus, IgA uniquely uncouples colonization from pathogenesis in commensal fungi to promote homeostasis.


Asunto(s)
Inmunidad Adaptativa , Candida albicans/inmunología , Candida albicans/fisiología , Interacciones Huésped-Patógeno/inmunología , Simbiosis/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Antígenos Fúngicos/inmunología , Candida albicans/patogenicidad , Colitis/inmunología , Colitis/microbiología , Colitis/patología , Femenino , Vacunas Fúngicas/inmunología , Microbioma Gastrointestinal/inmunología , Humanos , Hifa/inmunología , Inmunoglobulina A/inmunología , Masculino , Ratones , Persona de Mediana Edad , Adulto Joven
2.
Clin Proteomics ; 21(1): 23, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38481131

RESUMEN

BACKGROUND: Human tear protein biomarkers are useful for detecting ocular and systemic diseases. Unfortunately, existing tear film sampling methods (Schirmer strip; SS and microcapillary tube; MCT) have significant drawbacks, such as pain, risk of injury, sampling difficulty, and proteomic disparities between methods. Here, we present an alternative tear protein sampling method using soft contact lenses (SCLs). RESULTS: We optimized the SCL protein sampling in vitro and performed in vivo studies in 6 subjects. Using Etafilcon A SCLs and 4M guanidine-HCl for protein removal, we sampled an average of 60 ± 31 µg of protein per eye. We also performed objective and subjective assessments of all sampling methods. Signs of irritation post-sampling were observed with SS but not with MCT and SCLs. Proteomic analysis by mass spectrometry (MS) revealed that all sampling methods resulted in the detection of abundant tear proteins. However, smaller subsets of unique and shared proteins were identified, particularly for SS and MCT. Additionally, there was no significant intrasubject variation between MCT and SCL sampling. CONCLUSIONS: These experiments demonstrate that SCLs are an accessible tear-sampling method with the potential to surpass current methods in sampling basal tears.

3.
Angiogenesis ; 25(3): 397-410, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35212873

RESUMEN

Anthrax protective antigen (PA) is a potent inhibitor of pathological angiogenesis with an unknown mechanism. In anthrax intoxication, PA interacts with capillary morphogenesis gene 2 (CMG2) and tumor endothelial marker 8 (TEM8). Here, we show that CMG2 mediates the antiangiogenic effects of PA and is required for growth-factor-induced chemotaxis. Using specific inhibitors of CMG2 and TEM8 interaction with natural ligand, as well as mice with the CMG2 or TEM8 transmembrane and intracellular domains disrupted, we demonstrate that inhibiting CMG2, but not TEM8 reduces growth-factor-induced angiogenesis in the cornea. Furthermore, the antiangiogenic effect of PA was abolished when the CMG2, but not the TEM8, gene was disrupted. Binding experiments demonstrated a broad ligand specificity for CMG2 among extracellular matrix (ECM) proteins. Ex vivo experiments demonstrated that CMG2 (but not TEM8) is required for PA activity in human dermal microvascular endothelial cell (HMVEC-d) network formation assays. Remarkably, blocking CMG2-ligand binding with PA or CRISPR knockout abolishes endothelial cell chemotaxis but not chemokinesis in microfluidic migration assays. These effects are phenocopied by Rho inhibition. Because CMG2 mediates the chemotactic response of endothelial cells to peptide growth factors in an ECM-dependent fashion, CMG2 is well-placed to integrate growth factor and ECM signals. Thus, CMG2 targeting is a novel way to inhibit angiogenesis.


Asunto(s)
Quimiotaxis , Células Endoteliales , Neovascularización Patológica , Receptores de Péptidos , Animales , Células Endoteliales/metabolismo , Péptidos y Proteínas de Señalización Intercelular/genética , Ligandos , Ratones , Receptores de Péptidos/genética , Receptores de Péptidos/metabolismo
4.
Biochemistry ; 58(7): 875-882, 2019 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-30638014

RESUMEN

The African trypanosome, Trypanosoma brucei, is the causative agent of human African trypanosomiasis (HAT). African trypanosomes are extracellular parasites that possess a single flagellum that imparts a high degree of motility to the microorganisms. In addition, African trypanosomes show significant metabolic and structural adaptation to environmental conditions. Analysis of the ways that environmental cues affect these organisms generally requires rapid perfusion experiments in combination with single-cell imaging, which are difficult to apply under conditions of rapid motion. Microfluidic devices have been used previously as a strategy for trapping small motile cells in a variety of organisms, including trypanosomes; however, in the past, such devices required individual fabrication in a cleanroom, limiting their application. Here we demonstrate that a commercial microfluidic device, typically used for bacterial trapping, can trap bloodstream and procyclic form trypanosomes, allowing for rapid buffer exchange via perfusion. As a result, time-lapse single-cell microscopy images of these highly motile parasites were acquired during environmental variations. Using these devices, we have been able to perform and analyze perfusion-based single-cell tracking experiments of the responses of the parasite to changes in glucose availability, which is a major step in resolving the mechanisms of adaptation of kinetoplasts to their individual biological niches; we demonstrate utility of this tool for making measurements of procyclic form trypanosome intracellular glucose levels as a function of changes in extracellular glucose concentrations. These experiments demonstrate that cytosolic glucose equilibrates with external conditions as fast as, or faster than, the rate of solution exchange in the instrument.


Asunto(s)
Dispositivos Laboratorio en un Chip , Microscopía Fluorescente/instrumentación , Microscopía Fluorescente/métodos , Trypanosoma brucei brucei/fisiología , Fluoresceína , Glucosa/metabolismo , Análisis de la Célula Individual , Imagen de Lapso de Tiempo/instrumentación , Imagen de Lapso de Tiempo/métodos , Trypanosoma brucei brucei/citología
5.
J Biol Chem ; 292(19): 7795-7805, 2017 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-28348078

RESUMEN

Here we report the use of a fluorescein-tagged peroxisomal targeting sequence peptide (F-PTS1, acetyl-C{K(FITC)}GGAKL) for investigating pH regulation of glycosomes in live procyclic form Trypanosoma brucei When added to cells, this fluorescent peptide is internalized within vesicular structures, including glycosomes, and can be visualized after 30-60 min. Using F-PTS1 we are able to observe the pH conditions inside glycosomes in response to starvation conditions. Previous studies have shown that in the absence of glucose, the glycosome exhibits mild acidification from pH 7.4 ± 0.2 to 6.8 ± 0.2. Our results suggest that this response occurs under proline starvation as well. This pH regulation is found to be independent from cytosolic pH and requires a source of Na+ ions. Glycosomes were also observed to be more resistant to external pH changes than the cytosol; placement of cells in acidic buffers (pH 5) reduced the pH of the cytosol by 0.8 ± 0.1 pH units, whereas glycosomal pH decreases by 0.5 ± 0.1 pH units. This observation suggests that regulation of glycosomal pH is different and independent from cytosolic pH regulation. Furthermore, pH regulation is likely to work by an active process, because cells depleted of ATP with 2-deoxyglucose and sodium azide were unable to properly regulate pH. Finally, inhibitor studies with bafilomycin and EIPA suggest that both V-ATPases and Na+/H+ exchangers are required for glycosomal pH regulation.


Asunto(s)
Microcuerpos/química , Trypanosoma brucei brucei/química , Adenosina Trifosfato/química , Amilorida/análogos & derivados , Amilorida/química , Animales , Citosol/química , Desoxiglucosa/química , Digitonina/química , Glucosa/química , Homeostasis , Concentración de Iones de Hidrógeno , Macrólidos/química , Microscopía Fluorescente , Potasio/química , Prolina/química , Dominios Proteicos , Proteínas Protozoarias/química , Azida Sódica/química
6.
Anal Biochem ; 458: 43-8, 2014 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-24755004

RESUMEN

Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as optical labels for cell analysis using flow cytometry and microscopy. The excitation of plasmon resonances in nanoparticles results in strong depolarized scattering of visible light, permitting detection at the single nanoparticle level. The nanoparticles were modified with neutravidin via epoxide-azide coupling chemistry, to which biotinylated antibodies targeting cell surface receptors were bound. The nanoparticle labels exhibited long-term stability in solutions with high salt concentrations without aggregation or silver etching. Labeled cells exhibited two orders of magnitude enhancement of the scattering intensity compared with unlabeled cells.


Asunto(s)
Citometría de Flujo , Nanopartículas del Metal/química , Plata/química , Animales , Anticuerpos/inmunología , Anticuerpos Inmovilizados/inmunología , Avidina/química , Línea Celular , Proteínas Inmovilizadas/química , Proteínas Inmovilizadas/metabolismo , Luz , Macrófagos/química , Macrófagos/citología , Ratones , Receptores de Superficie Celular/inmunología , Dispersión de Radiación , Resonancia por Plasmón de Superficie
7.
Analyst ; 139(9): 2108-13, 2014 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-24503581

RESUMEN

Polypropylene (PP) capillary-channeled polymer (C-CP) fibers were modified by adsorption of a head group-functionalized lipid to generate analyte-specific surfaces for application as a stationary phase in high performance liquid chromatography (HPLC) or solid phase extraction (SPE). The aliphatic moiety of the lipid adsorbs strongly to the hydrophobic PP surface, with the hydrophilic active head groups orienting themselves toward the more polar mobile phase, thus allowing for interactions with the desired solutes. Initial proof-of-concept was achieved by adsorbing a biotin-poly(ethylene glycol)-functionalized lipid to the surface of the PP C-CP fibers. Surface modification and uniformity was evaluated by binding streptavidin labeled with Texas Red (SAv-TR) to the biotin moiety. Isolation of SAv-TR from a mixture in neat buffer and in cleared lysate demonstrated the capability of the modified fibers to extract an analyte of interest from a complex viscous mixture. It is believed that this surface modification approach is generally applicable to a diversity of selective protein immobilization applications, including clinical diagnostics and preparative scale HPLC on C-CP fibers as well as to other hydrophobic supports.


Asunto(s)
Lípidos/química , Polietilenglicoles/química , Polímeros/química , Cromatografía Líquida de Alta Presión , Espectrometría de Fluorescencia , Propiedades de Superficie
8.
J Vis Exp ; (203)2024 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-38314910

RESUMEN

Glucose metabolism is critical for the African trypanosome, Trypanosoma brucei, as an essential metabolic process and regulator of parasite development. Little is known about the cellular responses generated when environmental glucose levels change. In both bloodstream and procyclic form (insect stage) parasites, glycosomes house most of glycolysis. These organelles are rapidly acidified in response to glucose deprivation, which likely results in the allosteric regulation of glycolytic enzymes such as hexokinase. In previous work, localizing the chemical probe used to make pH measurements was challenging, limiting its utility in other applications. This paper describes the development and use of parasites that express glycosomally localized pHluorin2, a heritable protein pH biosensor. pHluorin2 is a ratiometric pHluorin variant that displays a pH (acid)-dependent decrease in excitation at 395 nm while simultaneously yielding an increase in excitation at 475 nm. Transgenic parasites were generated by cloning the pHluorin2 open reading frame into the trypanosome expression vector pLEW100v5, enabling inducible protein expression in either lifecycle stage. Immunofluorescence was used to confirm the glycosomal localization of the pHluorin2 biosensor, comparing the localization of the biosensor to the glycosomal resident protein aldolase. The sensor responsiveness was calibrated at differing pH levels by incubating cells in a series of buffers that ranged in pH from 4 to 8, an approach we have previously used to calibrate a fluorescein-based pH sensor. We then measured pHluorin2 fluorescence at 405 nm and 488 nm using flow cytometry to determine glycosomal pH. We validated the performance of the live transgenic pHluorin2-expressing parasites, monitoring pH over time in response to glucose deprivation, a known trigger of glycosomal acidification in PF parasites. This tool has a range of potential applications, including potentially being used in high-throughput drug screening. Beyond glycosomal pH, the sensor could be adapted to other organelles or used in other trypanosomatids to understand pH dynamics in the live cell setting.


Asunto(s)
Trypanosoma brucei brucei , Animales , Trypanosoma brucei brucei/metabolismo , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Glucosa/metabolismo , Microcuerpos/metabolismo , Animales Modificados Genéticamente , Concentración de Iones de Hidrógeno
9.
Lab Chip ; 24(8): 2202-2207, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38525691

RESUMEN

In this work, we present a new 3D printing technique that enables the realization of native digital micro-mirror device (DMD) resolution in negative features of a 3D printed part without improving 3D printer hardware and demonstrate the fabrication of fully integrated, biocompatible isoporous membranes with pore sizes as small as 7 µm. We utilize this technique to construct a microfluidic device that mimics an established organ-on-a-chip configuration, including an integrated isoporous membrane. Two cell populations are seeded on either side of the membrane and imaged as a proof of concept for other organ-on-a-chip applications. These 3D printed isoporous membranes can be leveraged for a wide variety of other mechanical and biological applications, creating new possibilities for seamlessly integrated, 3D printed microfluidic devices.


Asunto(s)
Dispositivos Laboratorio en un Chip , Impresión Tridimensional
10.
Biochemistry ; 52(21): 3629-37, 2013 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-23651061

RESUMEN

Studies of dynamic changes in organelles of protozoan parasite Trypanosoma brucei have been limited, in part because of the difficulty of targeting analytical probes to specific subcellular compartments. Here we demonstrate application of a ratiometric probe for pH quantification in T. brucei glycosomes. The probe consists of a peptide encoding the peroxisomal targeting sequence (F-PTS1, acetyl-CKGGAKL) coupled to fluorescein, which responds to pH. When incubated with living parasites, the probe is internalized within vesicular structures that colocalize with a glycosomal marker. Inhibition of uptake of F-PTS1 at 4 °C and pulse-chase colocalization with fluorescent dextran suggested that the probe is initially taken up by non-receptor-mediated endocytosis but is subsequently transported separately from dextran and localized within glycosomes, prior to the final fusion of labeled glycosomes and lysosomes as part of glycosomal turnover. Intraorganellar measurements and pH calibration with F-PTS1 in T. brucei glycosomes indicate that the resting glycosomal pH under physiological conditions is 7.4 ± 0.2. However, incubation in glucose-depleted buffer triggered mild acidification of the glycosome over a period of 20 min, with a final observed pH of 6.8 ± 0.3. This glycosomal acidification was reversed by reintroduction of glucose. Coupling of ratiometric fluorescent sensors and reporters to PTS peptides offers an invaluable tool for monitoring in situ glycosomal response(s) to changing environmental conditions and could be applied to additional kinetoplastid parasites.


Asunto(s)
Concentración de Iones de Hidrógeno , Microcuerpos/metabolismo , Trypanosoma brucei brucei/metabolismo , Animales , Citometría de Flujo , Fracciones Subcelulares/metabolismo
11.
Micromachines (Basel) ; 14(8)2023 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-37630125

RESUMEN

We demonstrate a method to effectively 3D print microfluidic devices with high-resolution features using a biocompatible resin based on avobenzone as the UV absorber. Our method relies on spectrally shaping the 3D printer source spectrum so that it is fully overlapped by avobenzone's absorption spectrum. Complete overlap is essential to effectively limit the optical penetration depth, which is required to achieve high out-of-plane resolution. We demonstrate the high resolution in practice by 3D printing 15 µm square pillars in a microfluidic chamber, where the pillars are separated by 7.7 µm and are printed with 5 µm layers. Furthermore, we show reliable membrane valves and pumps using the biocompatible resin. Valves are tested to 1,000,000 actuations with no observable degradation in performance. Finally, we create a concentration gradient generation (CG) component and utilize it in two device designs for cell chemotaxis studies. The first design relies on an external dual syringe pump to generate source and sink flows to supply the CG channel, while the second is a complete integrated device incorporating on-chip pumps, valves, and reservoirs. Both device types are seeded with adherent cells that are subjected to a chemoattractant CG, and both show clear evidence of chemotactic cellular migration. Moreover, the integrated device demonstrates cellular migration comparable to the external syringe pump device. This demonstration illustrates the effectiveness of our integrated chemotactic assay approach and high-resolution biocompatible resin 3D printing fabrication process. In addition, our 3D printing process has been tuned for rapid fabrication, as printing times for the two device designs are, respectively, 8 and 15 min.

12.
Anal Chem ; 84(18): 8013-9, 2012 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-22881392

RESUMEN

Sensors based upon surface-enhanced Raman spectroscopy (SERS) are attractive because they have narrow, vibrationally specific spectral peaks that can be excited using red and near-infrared light which avoids photobleaching, penetrates tissue, and reduces autofluorescence. Several groups have fabricated pH nanosensors by functionalizing silver or gold nanoparticle surfaces with an acidic molecule and measuring the ratio of protonated to deprotonated Raman bands. However, a limitation of these sensors is that macromolecules in biological systems can adsorb onto the nanoparticle surface and interfere with measurements. To overcome this interference, we encapsulated pH SERS sensors in a 30 nm thick silica layer with small pores which prevented bovine serum albumin (BSA) molecules from interacting with the pH-indicating 4-mercaptobenzoic acid (4-MBA) on the silver surfaces but preserved the pH-sensitivity. Encapsulation also improved colloidal stability and sensor reliability. The noise level corresponded to less than 0.1 pH units from pH 3 to 6. The silica-encapsulated functionalized silver nanoparticles (Ag-MBA@SiO(2)) were taken up by J774A.1 macrophage cells and measured a decrease in local pH during endocytosis. This strategy could be extended for detecting other small molecules in situ.


Asunto(s)
Benzoatos/análisis , Nanopartículas del Metal/química , Dióxido de Silicio/química , Plata/química , Espectrometría Raman , Compuestos de Sulfhidrilo/análisis , Animales , Bovinos , Línea Celular , Oro/química , Concentración de Iones de Hidrógeno , Ratones , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/metabolismo , Propiedades de Superficie
13.
Anal Bioanal Chem ; 404(10): 3003-14, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23052882

RESUMEN

While conjugated polymer nanoparticles (CPNs) have been widely touted as ultra-bright labels for biological imaging, no direct comparative measurements of their intracellular brightness have been reported. Simple in vitro comparisons are not definitive since fluorophore brightness in vitro may not correspond with intracellular brightness. We have compared the fluorescence brightness of J774A.1 cells loaded with 24 nm methoxy-capped 2,000 M(r) polyethylene glycol lipid PFBT nanoparticles (PEG lipid-PFBT CPNs) to cells loaded with carboxy-functionalized quantum dots (Qdots) or a dextran-linked small molecule organic dye, Alexa Fluor 488 dextran (AF488-dex). Under conditions likely to be used for biological imaging or flow cytometry, these CPNs are 175× brighter than Qdots and 1,400× brighter than AF488-dex in cells. Evaluation of the minimum incubation concentration required for detection of nanoparticle fluorescence with a commercial flow cytometer indicated that the limit of detection for PEG lipid-PFBT CPNs was 19 pM (86 ppb), substantially lower than values obtained for Qdots (980 pM) or AF488-dex (11.2 nM). Investigation of the mechanism of cellular uptake of the three fluid-phase labels indicates that these particles are passively taken into macrophage cells via macropinocytosis without interaction with cell surface receptors, and ultimately localize in lysosomes. In addition, no cytotoxicity could be observed at any of the CPN concentrations tested. Together, these data suggest that these CPNs are appropriate and attractive candidates as fluid-phase markers with significantly greater fluorescence brightness than existing dyes or nanoparticles. We expect that these CPNs will find application in both imaging and flow cytometry.


Asunto(s)
Fluorenos/química , Colorantes Fluorescentes/química , Macrófagos/citología , Nanopartículas/química , Polietilenglicoles/química , Polímeros/química , Puntos Cuánticos , Animales , Línea Celular , Supervivencia Celular , Dextranos/análisis , Dextranos/química , Fluorenos/análisis , Fluorescencia , Colorantes Fluorescentes/análisis , Ratones , Microscopía Fluorescente , Nanopartículas/análisis , Pinocitosis , Polietilenglicoles/análisis , Polímeros/análisis
14.
Biomaterials ; 283: 121464, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35306229

RESUMEN

Micropatterned suspension culture creates consistently sized and shaped cell aggregates but has not produced organotypic structures from stable cells, thus restricting its use in accurate disease modeling. Here, we show that organotypic structure is achieved in hybrid suspension culture via supplementation of soluble extracellular matrix (ECM). We created a viable lung organoid from epithelial, endothelial, and fibroblast human stable cell lines in suspension culture. We demonstrate the importance of soluble ECM in organotypic patterning with the emergence of lumen-like structures with airspace showing feasible gas exchange units, formation of branching, perfusable vasculature, and long-term 70-day maintenance of lumen structure. Our results show a dependent relationship between enhanced fibronectin fibril assembly and the incorporation of ECM in the organoid. We successfully applied this technology in modeling lung fibrosis via bleomycin induction and test a potential antifibrotic drug in vitro while maintaining fundamental cell-cell interactions in lung tissue. Our human fluorescent lung organoid (hFLO) model represents features of pulmonary fibrosis which were ameliorated by fasudil treatment. We also demonstrate a 3D culture method with potential of creating organoids from mature cells, thus opening avenues for disease modeling and regenerative medicine, enhancing understanding of lung cell biology in health and lung disease.


Asunto(s)
Matriz Extracelular , Fibrosis Pulmonar , Matriz Extracelular/metabolismo , Fibroblastos , Humanos , Pulmón , Organoides
15.
Exp Parasitol ; 127(2): 423-8, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20971104

RESUMEN

Hexokinases from the African trypanosome, Trypanosoma brucei, are attractive targets for the development of anti-parasitic drugs, in part because the parasite utilizes glycolysis exclusively for ATP production during the mammalian infection. Here, we have demonstrated that the bioflavanoid quercetin (QCN), a known trypanocide, is a mixed inhibitor of Trypanosoma brucei hexokinase 1 (TbHK1) (IC(50) = 4.1 ± 0.8µM). Spectroscopic analysis of QCN binding to TbHK1, taking advantage of the intrinsically fluorescent single tryptophan (Trp177) in TbHK1, revealed that QCN quenches emission of Trp177, which is located near the hinge region of the enzyme. ATP similarly quenched Trp177 emission, while glucose had no impact on fluorescence. Supporting the possibility that QCN toxicity is a consequence of inhibition of the essential hexokinase, in live parasites QCN fluorescence localizes to glycosomes, the subcellular home of TbHK1. Additionally, RNAi-mediated silencing of TbHK1 expression expedited QCN induced death, while over-expressing TbHK1 protected trypanosomes from the compound. In summary, these observations support the suggestion that QCN toxicity is in part attributable to inhibition of the essential TbHK1.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Hexoquinasa/antagonistas & inhibidores , Quercetina/farmacología , Tripanocidas/farmacología , Trypanosoma brucei brucei/efectos de los fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Flavonoides/química , Flavonoides/farmacología , Microcuerpos/metabolismo , Microscopía Fluorescente , Proyectos Piloto , Quercetina/química , Quercetina/metabolismo , Proteínas Recombinantes/antagonistas & inhibidores , Tripanocidas/química , Tripanocidas/metabolismo , Trypanosoma brucei brucei/enzimología , Trypanosoma brucei brucei/ultraestructura
16.
Nat Commun ; 12(1): 5509, 2021 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-34535656

RESUMEN

Traditional 3D printing based on Digital Light Processing Stereolithography (DLP-SL) is unnecessarily limiting as applied to microfluidic device fabrication, especially for high-resolution features. This limitation is due primarily to inherent tradeoffs between layer thickness, exposure time, material strength, and optical penetration that can be impossible to satisfy for microfluidic features. We introduce a generalized 3D printing process that significantly expands the accessible spatially distributed optical dose parameter space to enable the fabrication of much higher resolution 3D components without increasing the resolution of the 3D printer. Here we demonstrate component miniaturization in conjunction with a high degree of integration, including 15 µm × 15 µm valves and a 2.2 mm × 1.1 mm 10-stage 2-fold serial diluter. These results illustrate our approach's promise to enable highly functional and compact microfluidic devices for a wide variety of biomolecular applications.


Asunto(s)
Microfluídica , Miniaturización , Óptica y Fotónica , Impresión Tridimensional , Membranas , Presión , Microtomografía por Rayos X
17.
Nat Commun ; 12(1): 5337, 2021 09 09.
Artículo en Inglés | MEDLINE | ID: mdl-34504101

RESUMEN

TNK1 is a non-receptor tyrosine kinase with poorly understood biological function and regulation. Here, we identify TNK1 dependencies in primary human cancers. We also discover a MARK-mediated phosphorylation on TNK1 at S502 that promotes an interaction between TNK1 and 14-3-3, which sequesters TNK1 and inhibits its kinase activity. Conversely, the release of TNK1 from 14-3-3 allows TNK1 to cluster in ubiquitin-rich puncta and become active. Active TNK1 induces growth factor-independent proliferation of lymphoid cells in cell culture and mouse models. One unusual feature of TNK1 is a ubiquitin-association domain (UBA) on its C-terminus. Here, we characterize the TNK1 UBA, which has high affinity for poly-ubiquitin. Point mutations that disrupt ubiquitin binding inhibit TNK1 activity. These data suggest a mechanism in which TNK1 toggles between 14-3-3-bound (inactive) and ubiquitin-bound (active) states. Finally, we identify a TNK1 inhibitor, TP-5801, which shows nanomolar potency against TNK1-transformed cells and suppresses tumor growth in vivo.


Asunto(s)
Proteínas 14-3-3/genética , Proteínas Fetales/genética , Linfocitos/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Proteínas Tirosina Quinasas/genética , Ubiquitina/genética , Proteínas 14-3-3/metabolismo , Células A549 , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Proteínas Fetales/antagonistas & inhibidores , Proteínas Fetales/metabolismo , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Humanos , Linfocitos/efectos de los fármacos , Linfocitos/patología , Ratones , Fosfolipasa C gamma/genética , Fosfolipasa C gamma/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/mortalidad , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , Unión Proteica , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/metabolismo , Pirimidinas/farmacología , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Factor de Transcripción STAT5/genética , Factor de Transcripción STAT5/metabolismo , Transducción de Señal , Análisis de Supervivencia , Carga Tumoral/efectos de los fármacos , Ubiquitina/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
18.
Biomacromolecules ; 11(10): 2675-82, 2010 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-20863132

RESUMEN

Conjugated polymer nanoparticles are formed by precipitation of highly fluorescent conjugated polymers to form small nanoparticles with extremely bright fluorescence. We characterized cellular uptake and cytotoxicity of 18 ± 5 nm PFBT conjugated polymer nanoparticles in J774A.1 cells. Significant nanoparticle uptake was observed, indicating efficient nanoparticle entry into cells, even for short (1 h) incubations. The high fluorescence of these nanoparticles allows extremely low loading concentrations; PFBT nanoparticle fluorescence in cells could be detected with loading concentrations of 155 pM (270 ppb). Cellular uptake slows at low temperature, consistent with endocytic entry. Nanoparticles colocalize with Texas Red dextran and are trafficked to lysosomes, as demonstrated by the location of nanoparticle fluorescence in perinuclear organelles that also stain with an anti-LAMP-1 antibody. Inhibition of uptake by phosphoinositide 3-kinase inhibitors implicates macropinocytosis as the operative endocytic mechanism. No significant cytotoxic or inflammatory effects could be observed, making PFBT nanoparticles attractive probes for live cell imaging.


Asunto(s)
Fluorenos/metabolismo , Fluorescencia , Macrófagos/metabolismo , Imagen Molecular/métodos , Nanopartículas/química , Polímeros/metabolismo , Animales , Técnicas de Cultivo de Célula , Línea Celular , Citometría de Flujo , Fluorenos/química , Ratones , Microscopía de Fuerza Atómica , Microscopía Fluorescente , Polímeros/química
19.
Front Immunol ; 11: 561889, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33542711

RESUMEN

CD4+ T cells are crucial for effective repression and elimination of cancer cells. Despite a paucity of CD4+ T cell receptor (TCR) clinical studies, CD4+ T cells are primed to become important therapeutics as they help circumvent tumor antigen escape and guide multifactorial immune responses. However, because CD8+ T cells directly kill tumor cells, most research has focused on the attributes of CD8+ TCRs. Less is known about how TCR affinity and CD4 expression affect CD4+ T cell activation in full length TCR (flTCR) and TCR single chain signaling (TCR-SCS) formats. Here, we generated an affinity panel of TCRs from CD4+ T cells and expressed them in flTCR and three TCR-SCS formats modeled after chimeric antigen receptors (CARs) to understand the contributions of TCR-pMHCII affinity, TCR format, and coreceptor CD4 interactions on CD4+ T cell activation. Strikingly, the coreceptor CD4 inhibited intermediate and high affinity TCR-construct activation by Lck-dependent and -independent mechanisms. These inhibition mechanisms had unique affinity thresholds dependent on the TCR format. Intracellular construct formats affected the tetramer staining for each TCR as well as IL-2 production. IL-2 production was promoted by increased TCR-pMHCII affinity and the flTCR format. Thus, CD4+ T cell therapy development should consider TCR affinity, CD4 expression, and construct format.


Asunto(s)
Antígenos CD4/metabolismo , Activación de Linfocitos , Modelos Inmunológicos , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Receptores Quiméricos de Antígenos/inmunología , Transducción de Señal/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Antígenos de Neoplasias/inmunología , Antígenos de Histocompatibilidad Clase II/inmunología , Hibridomas , Inmunoterapia Adoptiva/métodos , Interleucina-2/metabolismo , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores Quiméricos de Antígenos/genética , Transducción Genética , Levaduras/inmunología
20.
ACS Appl Bio Mater ; 3(4): 2239-2244, 2020 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-32467881

RESUMEN

We report a non-cytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The non-cytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively non-cytotoxic with a post-print 12-hour ethanol wash, and that A-PEGDA, as-printed, is effectively non-cytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultra-low adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures.

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