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1.
Cell Stem Cell ; 30(11): 1434-1451.e9, 2023 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-37922878

RESUMEN

Most organs have tissue-resident immune cells. Human organoids lack these immune cells, which limits their utility in modeling many normal and disease processes. Here, we describe that pluripotent stem cell-derived human colonic organoids (HCOs) co-develop a diverse population of immune cells, including hemogenic endothelium (HE)-like cells and erythromyeloid progenitors that undergo stereotypical steps in differentiation, resulting in the generation of functional macrophages. HCO macrophages acquired a transcriptional signature resembling human fetal small and large intestine tissue-resident macrophages. HCO macrophages modulate cytokine secretion in response to pro- and anti-inflammatory signals and were able to phagocytose and mount a robust response to pathogenic bacteria. When transplanted into mice, HCO macrophages were maintained within the colonic organoid tissue, established a close association with the colonic epithelium, and were not displaced by the host bone-marrow-derived macrophages. These studies suggest that HE in HCOs gives rise to multipotent hematopoietic progenitors and functional tissue-resident macrophages.


Asunto(s)
Células Madre Pluripotentes , Humanos , Ratones , Animales , Células Madre Hematopoyéticas , Colon , Organoides , Macrófagos
2.
Heliyon ; 9(11): e21460, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37954337

RESUMEN

Background and aims: Numerous strategies for enhancing seed germination and growth have been employed over the decades. Despite these advancements, there continues to be a demand for more effective techniques, driven by the growing global population. Recently, various forms of non-thermal atmospheric pressure plasma have garnered attention as environmentally friendly, safe, and cost-effective methods to enhance the agricultural and food sectors. This study explores the remarkable impact of non-thermal plasma (NTP) treatment on cucumber (Cucumis sativus L.) seed germination. Methods: A cost-effective, custom-designed power supply operating at line frequency was used for treating seeds, with exposure times ranging from 1 to 7 min. Various germination parameters, including water contact angle measurements, mass loss, water imbibition rate, and seedling length, were evaluated to assess the impact of plasma treatment on seed germination. Results: Cucumber seeds exposed to NTP treatment for 3 min and 5 min durations showed significant germination improvements, notably a 57.9 ± 4.25 % higher final germination percentage, 14.5 ± 3.75 % reduced mean germination time, and a remarkable 90.6 ± 4.64 % increase in germination index compared to the control. These results suggest that NTP treatment enhanced seed coat permeability, triggered essential biochemical processes, and expedited water absorption and nutrient assimilation, ultimately fostering faster and more synchronized germination. Conclusions: Our findings underscore the potential of NTP as an innovative approach to improving seed germination in agricultural practices.

3.
Nat Commun ; 14(1): 7604, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37989749

RESUMEN

Direct utilization of CO2 into organic synthesis finds enormous applications to synthesize pharmaceuticals and fine chemicals. However, pure CO2 gas is essential to achieve these transformations, and the purification of CO2 is highly cost and energy intensive. Considering this, we describe a straightforward synthetic route for the synthesis of γ-lactams, a pivotal core structure of bioactive molecules, by using commercially available starting materials (alkenes and amines) and impure CO2 stream (exhaust gas is collected from the car) as the carbon source. This blueprint features a broad scope, excellent functional group compatibility and application to the late-stage transformation of existing pharmaceuticals and natural products to synthesize functionalized γ-lactams. We believe that our strategy will provide direct access to γ-lactams in a very sustainable way and will also enhance the Carbon Capture and Utilization (CCU) strategy.

4.
Int J Microbiol ; 2023: 6439466, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37583475

RESUMEN

Streptomyces are bacteria well known for producing bioactive secondary metabolites which are commonly found in diverse habitats. The biosynthesis of metabolites from Streptomyces is influenced by various factors such as the growth medium, environmental conditions, and gene regulation. This study aimed to investigate the influence of different growth media on biomass production and the antioxidant and enzyme inhibitory potential of a crude extract obtained from Streptomyces sp. G-18 isolated from high altitudinal soil of Nepal. The highest dry weight growth was observed in R2YE medium (184 mg/L), followed by R5 (144 mg/L), YEME (38 mg/L), and R5M media (30 mg/L). The crude extract showed notable antioxidant activities against free radicals. The highest alpha-amylase inhibition was observed in the R2YE medium, and worthy lipase and tyrosinase inhibition was observed in the YEME medium. However, only the R2YE medium exhibited inhibitory potential against elastase and acetylcholinesterase, while crude extracts from R5, YEME, and R5 modified did not show any such activity. Overall, our findings suggest that the production of bioactive secondary metabolites in Streptomyces sp. G-18 was significantly influenced by the growth medium. This strain may be a promising source of enzyme inhibitors with potential applications in the pharmaceutical and cosmetic industries.

5.
J Phys Condens Matter ; 35(12)2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36596261

RESUMEN

We report rich magnetic behavior for Co-Ir based double perovskites consisting of different rare earth cations Pr and Nd: Pr2CoIrO6(PCIO) and Nd2CoIrO6(NCIO). Both oxides show an antisite disorder of 10% and a ferrimagnetic transition,TFiMaround 96 K and 98 K respectively. The long range magnetic ordering is arising from the canted antiferromagnetic ordering between the Co2+and Ir4+ions. A prominent peak around 27 K in magnetization data of NCIO indicates that the total moment of Nd ion is antiferromagnetically coupled to the Co-Ir sublattice. The long range order of the Nd sublattice is corroborated by the evidence of an anomaly in specific heat at very low temperature. The compounds exhibit a maximum change of magnetic entropy of 0.57 (0.48) J kg.K-1atTFiMin a magnetic field of 5 T. The strong spin-orbit coupling in 5dstates of Ir and cation disorder lead to the Mott insulating phase as found from the analysis of temperature dependent resistivity. These unique behaviors suggest an interesting interplay between localized Pr/Nd-4f, itinerant Co-3dand Ir-5delectrons.

6.
Pathog Immun ; 8(2): 59-73, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38361525

RESUMEN

Background: Liver dysfunction is one of the hallmarks of SARS-CoV-2 infection. The mechanism(s) of hepatic injury in SARS-CoV-2 infection remains controversial with some reporting viral replication and cellular injury and others suggesting lack of replication and injury due to non-cytopathogenic etiologies. To investigate this further, we evaluated SARS-CoV-2 replication in immortalized hepatic cell lines and primary hepatocytes, examined whether cell injury was associated with apoptotic pathways, and also determined the effect of the antiviral remdesivir on these processes. Methods: Immortalized hepatocyte cell lines (HepG2 and Huh7.5), as well as primary human hepatocytes, were exposed to SARS-CoV-2 at a multiplicity of infection of 0.1 PFU/mL. Viral replication was evaluated by plaque assays, immunohistochemical staining for the viral spike protein, and caspase-3 expression evaluated with and without exposure to remdesivir. Results: All hepatocyte cell lines and primary hepatocytes supported active replication of SARS-CoV-2. Significant cytopathic effect was observed by light microscopy, and caspase-3 staining supported activation of apoptotic pathways. Remdesivir abrogated infection in a dose-dependent fashion and was not independently associated with hepatocyte injury. Conclusion: Hepatocytes appear to be highly permissive of SARS-CoV-2 replication which leads to rapid cell death associated with activation of apoptotic pathways. Viral replication and hepatocytes injury are abrogated with remdesivir. We conclude that active viral replication is most likely a key contributor to liver enzyme abnormalities observed in the setting of acute SARS-CoV-2 infection.

7.
Org Lett ; 24(12): 2452-2456, 2022 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-35298180

RESUMEN

The unique property of hexafluoroisopropanol (HFIP) enables the regioselective hydroamination of 1,3-dienes with nitrogen heterocycles in a Markovnikov manner in the presence of catalytic Brønsted acid. This transition-metal-free intermolecular hydroamination protocol is achieved under mild reaction conditions. The aggregation by HFIP and Brønsted acid helps to activate the terminal double bond regioselectively. Following the protonation of diene, the C-N bond formation is accomplished upon the involvement of heterocyclic amines.

8.
Angew Chem Int Ed Engl ; 61(9): e202115272, 2022 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-34821454

RESUMEN

A visible light photoredox catalytic method for the selective cleavage of single strong C-F bond in trifluoromethyl ketones is reported. Single electron reduction of trifluoromethyl ketones generates difluoromethyl radicals which can be engaged in intermolecular C-C bond formation with N-methyl-N-arylmethacrylamides to furnish fluorine-containing oxindole derivatives in good yields. The reaction shows excellent chemoselectivity with good functional group tolerance under mild conditions. 1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) as a solvent plays a critical role for the selective single C-F bond cleavage. High-level DFT calculations are depicted to shed light on the mechanism.

9.
Int J Microbiol ; 2021: 9948738, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34249126

RESUMEN

Flavonoids have achieved widespread importance in pharmaceutical, food, and cosmetics industries. Furthermore, modification of these naturally occurring flavonoids to structurally diverse compounds through whole cell biotransformation with enhanced biological activities has numerous biotechnological applications. The present study investigated the biotransformation potential of Streptomyces species isolated from a high-altitude-soil sample towards selected flavonoid molecules. The biotransformed metabolites were confirmed by comparing the HPLC chromatogram with authentic compounds and LC-MS/MS analysis. Of these isolates, Streptomyces species G-18 (Accession number: MW663767.1) catalyzed isoflavone molecules daidzein and genistein to produce hydroxylated products at 24 h of reaction condition in a whole cell system. The hydroxylation of daidzein (4',7-dihydroxyisoflavone) was confirmed at 3'-position of the B ring to produce 3',4',7-trihydroxyisoflavone. In addition, Streptomyces species G-14 (Accession number: MW663770.1) and Streptomyces species S4L (Accession number: MW663769.1) also revealed the transformation of daidzein (4',7-dihydroxyisoflavone) to hydroxy daidzein at a distinct position than that of G-18 isolates, whereas thee Streptomyces species S4L reaction mixture with naringenin as a substrate also revealed the hydroxylated product. Our results demonstrated that microorganisms isolated from different ecological niches have broad application.

10.
Org Lett ; 23(15): 6148-6152, 2021 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-34284588

RESUMEN

A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.

11.
J Phys Condens Matter ; 33(33)2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-34049299

RESUMEN

Iridium-based double perovskites having mixed 3d-5d-4fmagnetic sub-lattices are expected to exhibit exotic magnetic phenomenon. In this paper, we report a study of structural, magnetic and transport properties of the mixed 3d-5d-4fdouble perovskite Sm2CoIrO6(SMCO), which crystallizes in monoclinic structure with space groupP21/nand the crystal symmetry remains same throughout the measured temperature down to 15 K. High resolution synchrotron x-ray diffraction reveals an isostructural phase transition around 104 K. Magnetization measurements on polycrystalline samples indicate that SMCO orders ferrimagnetically atTFiM= 104 K; while, a second transition is observed below 10 K due to the rare-earth (Sm3+) ordering. The ferrimagnetic transition is well-understood by Néel's two-sublattice model, which is primarily ascribed to antiferromagnetic coupling between Co2+and Ir4+sub-lattices. Electronic transport measurement shows the insulting behaviour of SMCO, which follows Mott variable-range hopping conduction mechanism. However, dielectric measurements as a function of temperature rules out the presence of magneto dielectric coupling in this compound.

12.
Chemistry ; 27(7): 2254-2269, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32931070

RESUMEN

CO2 is a highly abundant, green, and sustainable carbon feedstock. Despite its kinetic inertness and thermodynamic stability, the development of various catalytic techniques has enabled the conversion of CO2 to value-added products such as carboxylic acids, amino acids, and heterocyclic compounds, where visible-light photocatalysis has emerged to be an efficient promoter of these processes. This Minireview covers the progress in the areas of CO2 incorporation onto organic matters based on the combined venture of renewable resources of CO2 and light energy with significant emphasis on the last three years' developments.

13.
J Phys Condens Matter ; 32(49): 495702, 2020 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-32914762

RESUMEN

Polycrystalline Nd2CoIrO6 double perovskite crystallizes in monoclinic crystal structure with P21/n space group. The average grain size of powder sample is 400-500 nm. The dielectric, impedance and ac conductivity of the sample were studied in the temperature range 5-300 K and in the frequency range 20 Hz-2 MHz. Dielectric constant reveals a step like increase from low temperature value of ∼5 to colossal value of ∼104 at high temperature. High value of dielectric constant is associated with Maxwell-Wagner polarization due to large grain boundary capacitance. Cations (Co2+ and Ir4+) disorder leads to variable range hopping conduction of electrons in grain and grain boundary regions. Distribution of grain size induces distribution of relaxation time as confirmed from depressed semicircles in Nyquist plots. Frequency dependent conductivity follows universal power law behavior.

14.
mBio ; 11(4)2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32636253

RESUMEN

Escherichia coli strain Nissle has been used as a probiotic and therapeutic agent for over a century. Reports suggest that Nissle protects mice from enterohemorrhagic E. coli (EHEC) O157:H7 strains; however, mice are not very susceptible to O157:H7 and are not accurate models for O157:H7 infection in humans. Also, Nissle is closely related to uropathogenic E. coli (UPEC) strain CFT073, suggesting that Nissle could have pathogenic potential. To assess the safety of and protection conferred by Nissle, we modeled infection in stem cell-derived human intestinal organoids (HIOs). HIOs replicate the structure and function of human intestinal tissue. HIOs have a lumen enclosed by a single cell layer of differentiated epithelium, which is surrounded by a diffuse mesenchymal layer. An epithelial barrier which excludes the luminal contents from the surrounding cell layers and medium develops. Nissle appeared to be nonpathogenic; 103 CFU were microinjected into the lumen, and after 3 days, 107 CFU were recovered and the epithelial barrier remained intact. In contrast, microinjected EHEC and UPEC bacteria destroyed the epithelial barrier. To assess the protection conferred by Nissle, HIOs microinjected with Nissle were challenged after 18 to 24 h with EHEC or UPEC. Preincubation with Nissle prevented the loss of the epithelial barrier function, the loss of E-cadherin expression, the increased production of reactive oxygen species, and apoptosis. Nissle did not replicate in the HIO coculture, while the pathogenic strains did replicate, suggesting that Nissle conferred protection via activation of host defenses and not by eliminating competing strains. Nissle was shown to be susceptible to some Shiga toxin phage, and Nissle lysogens could produce Shiga toxin.IMPORTANCE Probiotic, or beneficial, bacteria, such as E. coli Nissle, hold promise for the treatment of human disease. More study is needed to fully realize the potential of probiotics. Safety and efficacy studies are critically important; however, mice are poor models for many human intestinal diseases. We used stem cell-derived human intestinal organoid tissues to evaluate the safety of Nissle and its ability to protect from pathogenic E. coli bacteria. Nissle was found to be safe. Human intestinal tissues were not harmed by the Nissle bacteria introduced into the digestive tract. In contrast, pathogenic E. coli bacteria destroyed the intestinal tissues, and importantly, Nissle conferred protection from the pathogenic E. coli bacteria. Nissle did not kill the pathogenic E. coli bacteria, and protection likely occurred via the activation of human defenses. Human intestinal tissues provide a powerful way to study complex host-microbe interactions.


Asunto(s)
Escherichia coli/fisiología , Intestinos/microbiología , Organoides/microbiología , Probióticos , Bacteriófagos , Recuento de Colonia Microbiana , Escherichia coli/clasificación , Escherichia coli/crecimiento & desarrollo , Escherichia coli O157/fisiología , Humanos , Toxina Shiga
15.
BMC Complement Med Ther ; 20(1): 198, 2020 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-32586304

RESUMEN

BACKGROUND: The Bergenia species are perennial herbs native to central Asia, and one of the most promising medicinal plants of the family Saxifragaceae which are popularly known as 'Pashanbheda'. The aim of this study was to evaluate antioxidant and α-amylase, α-glucosidase, lipase, tyrosinase, elastase, and cholinesterases inhibition potential of Bergenia pacumbis of Nepali origin collected from the Karnali region of Nepal. METHODS: The sequential crude extracts were made in hexane, ethyl acetate, methanol, and water. Antioxidant activities were analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. The α-amylase, α-glucosidase, lipase, tyrosinase, elastase, acetylcholinesterase, and butyrylcholinesterase inhibition were analyzed by the 3,5-Dinitrosalicylic acid (DNSA), p-Nitrophenyl-α-D-glucopyranoside (p-NPG), 4-nitrophenyl butyrate (p-NPB), l-3,4-dihydroxyphenylalanine (L-DOPA), N-Succinyl-Ala-Ala-p-nitroanilide (AAAPVN), acetylthiocholine, and butyrylcholine as a respective substrate. The major metabolites were identified by high performance liquid chromatography with electron spray ionization- quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) profiling. RESULTS: Our results revealed the great antioxidant ability of crude extract of B. pacumbis in ethyl acetate extract against both DPPH (IC50 = 30.14 ± 0.14 µg/mL) and ABTS (IC50 = 17.38 ± 1.12 µg/mL). However, the crude methanol extract of B. pacumbis showed the comparable enzymes inhibitions with standard drugs; α-amylase (IC50 = 14.03 ± 0.04 µg/mL), α-glucosidase (IC50 = 0.29 ± 0.00 µg/mL), lipase (IC50 = 67.26 ± 0.17 µg/mL), tyrosinase (IC50 = 58.25 ± 1.63 µg/mL), elastase (IC50 = 74.00 ± 3.03 µg/mL), acetylcholinesterase (IC50 = 31.52 ± 0.58 µg/mL), and butyrylcholinesterase (IC50 = 11.69 ± 0.14 µg/mL). On the basis of HPLC-ESI-QTOF-MS profiling of metabolites, we identified major compounds such as Bergenin, Catechin, Arbutin, Gallic acid, Protocatechuic acid, Syringic acid, Hyperoside, Afzelechin, Methyl gallate, Paashaanolactone, Astilbin, Quercetin, Kaempferol-7-O-glucoside, Diosmetin, Phloretin, and Morin in methanol extract which has reported beneficial bioactivities. CONCLUSION: Our study provides a plethora of scientific evidence that the crude extracts of B. pacumbis from Nepalese origin in different extracting solvents have shown significant potential on inhibiting free radicals as well as enzymes involved in digestion, skin related problems, and neurological disorders compared with the commercially available drugs.


Asunto(s)
Antioxidantes/farmacología , Inhibidores Enzimáticos/farmacología , Extractos Vegetales/farmacología , Saxifragaceae/química , Antioxidantes/química , Colinesterasas/metabolismo , Inhibidores Enzimáticos/química , Lipasa/metabolismo , Estructura Molecular , Monofenol Monooxigenasa/metabolismo , Nepal , Elastasa Pancreática/metabolismo , Extractos Vegetales/química , alfa-Amilasas/metabolismo , alfa-Glucosidasas/metabolismo
16.
Chem Biodivers ; 17(6): e2000155, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32304171

RESUMEN

The objective of this study was to profile the chemical components and biological activity analysis of crude extract of Bryophyllum pinnatum and Oxalis corniculata. Results revealed that the analyzed plant materials encompass the high amount of total phenolic and flavonoids content and have significant antioxidant activities. Furthermore, methanol extracts are the potential source of α-amylase, α-glucosidase, lipase, tyrosinase and elastase inhibitors. High resolution mass spectrometry revealed the presence of diverse metabolites such as quercetin 3-O-α-L-rhamnopyranoside, myricetin 3-rhamnoside, bersaldegenin 1,3,5-orthoacetate, bryophyllin C, syringic acid, caffeic acid, p-coumaric acid, and quercetin in B. pinnatum and isoorientin, swertisin, apigenin 7,4'-diglucoside, vitexin, 4-hydroxybenzoic acid, vanillic acid, ethyl gallate, 3,3',4'-trihydroxy-5,7-dimethoxyflavone, and diosmetin-7-O-ß-D-glucopyranoside in O. corniculata. Our finding suggested that these two plant species have high medicinal importance and are potential source of inhibitors for modern pharmaceuticals, nutraceuticals and cosmetics industries.


Asunto(s)
Inhibidores Enzimáticos/química , Kalanchoe/química , Oxalidaceae/química , Extractos Vegetales/química , Cromatografía Líquida de Alta Presión , Inhibidores Enzimáticos/metabolismo , Flavonoides/química , Flavonoides/metabolismo , Kalanchoe/metabolismo , Monofenol Monooxigenasa/antagonistas & inhibidores , Monofenol Monooxigenasa/metabolismo , Nepal , Oxalidaceae/metabolismo , Fenoles/química , Fenoles/metabolismo , Extractos Vegetales/metabolismo , Espectrometría de Masa por Ionización de Electrospray , alfa-Amilasas/antagonistas & inhibidores , alfa-Amilasas/metabolismo , alfa-Glucosidasas/química , alfa-Glucosidasas/metabolismo
17.
Chem Commun (Camb) ; 56(37): 5054-5057, 2020 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-32248220

RESUMEN

Aromatic amines and (hetero)arenes, such as indoles and pyrroles, are regioselectively sulfinylated under mild aerobic conditions using nitrosoarenes as a redox-catalyst. The nitrosoarene is involved in the electron transfer process with arenes to generate a crucial arene radical cation intermediate for C-H sulfinylation. The present methodology requires no directing group, can be scaled up easily and is applicable for the late-stage functionalization of drug molecules and natural products with high regioselectivity.

18.
J Phys Condens Matter ; 32(30): 305803, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32209753

RESUMEN

La2CuIrO6 is a spin-orbit coupled Mott insulator, and shows a transition to noncollinear antiferromagnetic state from paramagnetic state below 74 K, and further into a weak ferromagnetic state below 54 K. Despite having two different magnetic phases, the La2CuIrO6 compound does not exhibit exchange bias phenomenon. In this present work, we report an experimental investigation on the structural and magnetic properties of the double perovskite compound La2Cu0.9Cr0.1IrO6 through high-resolution synchrotron x-ray diffraction, x-ray absorption near edge structure (XANES), and temperature and field-dependent magnetization measurements. Powder x-ray diffraction analysis reveals that the sample crystallizes in triclinic structure (space group P [Formula: see text]) alike parent La2CuIrO6 compound, while XANES measurements rule out the possibility of valence state alteration between constituting elements in this sample. Interestingly, La2Cu0.9Cr0.1IrO6 compound is found to exhibit ferromagnetic cluster glass behavior, where field-cooled magnetization undergoes two ferromagnetic transitions. A significant enhancement of ferromagnetic component is also evident from hysteresis loop study, which is likely associated with the electron hopping between J eff = 1/2 pseudospin state of Ir4+ ions and empty eg-orbital of Cr3+ ions. Exclusively, this Cr-doped compound exhibits exchange bias effect, which is related to the complex interfacial exchange coupling between the ferromagnetic clusters and the host antiferromagnetic matrix.

19.
Cell Mol Gastroenterol Hepatol ; 10(1): 171-190, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32145469

RESUMEN

BACKGROUND & AIMS: Shiga toxin (Stx)-producing Escherichia coli (eg, O157:H7) infection produces bloody diarrhea, while Stx inhibits protein synthesis and causes the life-threatening systemic complication of hemolytic uremic syndrome. The murine intestinal tract is resistant to O157:H7 and Stx, and human cells in culture fail to model the complex tissue responses to intestinal injury. We used genetically identical, human stem cell-derived intestinal tissues of varying complexity to study Stx toxicity in vitro and in vivo. METHODS: In vitro susceptibility to apical or basolateral exposure to Stx was assessed using human intestinal organoids (HIOs) derived from embryonic stem cells, or enteroids derived from multipotent intestinal stem cells. HIOs contain a lumen, with a single layer of differentiated epithelium surrounded by mesenchymal cells. Enteroids only contain epithelium. In vivo susceptibility was assessed using HIOs, with or without an enteric nervous system, transplanted into mice. RESULTS: Stx induced necrosis and apoptotic death in both epithelial and mesenchymal cells. Responses that require protein synthesis (cellular proliferation and wound repair) also were observed. Epithelial barrier function was maintained even after epithelial cell death was seen, and apical to basolateral translocation of Stx was seen. Tissue cross-talk, in which mesenchymal cell damage caused epithelial cell damage, was observed. Stx induced mesenchymal expression of the epithelial marker E-cadherin, the initial step in mesenchymal-epithelial transition. In vivo responses of HIO transplants injected with Stx mirrored those seen in vitro. CONCLUSIONS: Intestinal tissue responses to protein synthesis inhibition by Stx are complex. Organoid models allow for an unprecedented examination of human tissue responses to a deadly toxin.


Asunto(s)
Células Epiteliales/patología , Infecciones por Escherichia coli/patología , Síndrome Hemolítico-Urémico/patología , Toxinas Shiga/toxicidad , Animales , Apoptosis , Línea Celular , Modelos Animales de Enfermedad , Infecciones por Escherichia coli/microbiología , Síndrome Hemolítico-Urémico/microbiología , Células Madre Embrionarias Humanas , Humanos , Mucosa Intestinal , Ratones , Necrosis , Organoides , Toxinas Shiga/metabolismo , Escherichia coli Shiga-Toxigénica/metabolismo , Escherichia coli Shiga-Toxigénica/patogenicidad
20.
J Vis Exp ; (156)2020 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-32150154

RESUMEN

Immune cell subtype population frequencies can have a large effect on the efficacy of T cell therapies. Current methods, like flow cytometry, have specific sample requirements, high sample input, are low throughput, and are difficult to standardize, all of which are detrimental to characterization of cell therapy products during their development and manufacturing. The assays described herein accurately identify and quantify immune cell types in a heterogeneous mixture of cells using isolated genomic DNA (gDNA). DNA methylation patterns are revealed through bisulfite conversion, a process in which unmethylated cytosines are converted to uracils. Unmethylated DNA regions are detected through qPCR amplification using primers targeting converted areas. One unique locus per assay is measured and serves as an accurate identifier for a specific cell type. The assays are robust and identify CD8+, regulatory, and Th17 T cells in a high throughput manner. These optimized assays can potentially be used for in-process and product release testing for cell therapy process.


Asunto(s)
Linfocitos T CD8-positivos/citología , Metilación de ADN , Epigénesis Genética , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Linfocitos T Reguladores/citología , Células Th17/citología , Linfocitos T CD8-positivos/metabolismo , Células Cultivadas , Humanos , Análisis de Secuencia de ADN/métodos , Sulfitos/química , Linfocitos T Reguladores/metabolismo , Células Th17/metabolismo
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