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Somatic cells can be reprogrammed into pluripotent stem cells (PSCs) by using pure chemicals, providing a different paradigm to study somatic reprogramming. However, the cell fate dynamics and molecular events that occur during the chemical reprogramming process remain unclear. We now show that the chemical reprogramming process requires the early formation of extra-embryonic endoderm (XEN)-like cells and a late transition from XEN-like cells to chemically-induced (Ci)PSCs, a unique route that fundamentally differs from the pathway of transcription factor-induced reprogramming. Moreover, precise manipulation of the cell fate transition in a step-wise manner through the XEN-like state allows us to identify small-molecule boosters and establish a robust chemical reprogramming system with a yield up to 1,000-fold greater than that of the previously reported protocol. These findings demonstrate that chemical reprogramming is a promising approach to manipulate cell fates.
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Técnicas de Reprogramação Celular , Células-Tronco Pluripotentes/citologia , Animais , Descoberta de Drogas , Embrião de Mamíferos/citologia , Endoderma/citologia , Endoderma/metabolismo , Fibroblastos/metabolismo , Expressão Gênica , Camundongos , Células-Tronco Pluripotentes/efeitos dos fármacosRESUMO
The mechanisms by which the relatively conserved spliceosome manages the enormously large number of splicing events that occur in humans (â¼200 000 versus â¼300 in yeast) are poorly understood. Here, we show deposition of one RNA modification-N2-methylguanosine (m2G) on the G72 of U6 snRNA (the catalytic center of the spliceosome) promotes efficient pre-mRNA splicing activity in human cells. This modification was identified to be conserved among vertebrates. Further, THUMPD2 was demonstrated as the methyltransferase responsible for U6 m2G72 by explicitly recognizing the U6-specific sequences and structural elements. The knock-out of THUMPD2 eliminated U6 m2G72 and impaired the pre-mRNA splicing activity, resulting in thousands of changed alternative splicing events of endogenous pre-mRNAs in human cells. Notably, the aberrantly spliced pre-mRNA population elicited the nonsense-mediated mRNA decay pathway. We further show that THUMPD2 was associated with age-related macular degeneration and retinal function. Our study thus demonstrates how an RNA epigenetic modification of the major spliceosome regulates global pre-mRNA splicing and impacts physiology and disease.
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Precursores de RNA , Splicing de RNA , Proteínas de Ligação a RNA , Degeneração Retiniana , Animais , Humanos , Metilação , Conformação de Ácido Nucleico , Degeneração Retiniana/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Splicing de RNA/genética , RNA Nuclear Pequeno/metabolismo , Saccharomyces cerevisiae/genética , Spliceossomos/genética , Spliceossomos/metabolismoRESUMO
Quasars, which are exceptionally bright objects at the centres (or nuclei) of galaxies, are thought to be produced through the accretion of gas into disks surrounding supermassive black holes1-3. There is observational evidence at galactic and circumnuclear scales4 that gas flows inwards towards accretion disks around black holes, and such an inflow has been measured at the scale of the dusty torus that surrounds the central accretion disk5. At even smaller scales, inflows close to an accretion disk have been suggested to explain the results of recent modelling of the response of gaseous broad emission lines to continuum variations6,7. However, unambiguous observations of inflows that actually reach accretion disks have been elusive. Here we report the detection of redshifted broad absorption lines of hydrogen and helium atoms in a sample of quasars. The lines show broad ranges of Doppler velocities that extend continuously from zero to redshifts as high as about 5,000 kilometres per second. We interpret this as the inward motion of gases at velocities comparable to freefall speeds close to the black hole, constraining the fastest infalling gas to within 10,000 gravitational radii of the black hole (the gravitational radius being the gravitational constant multiplied by the object mass, divided by the speed of light squared). Extensive photoionization modelling yields a characteristic radial distance of the inflow of approximately 1,000 gravitational radii, possibly overlapping with the outer accretion disk.
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The cuprate high-temperature superconductors exhibit many unexplained electronic phases, but the superconductivity at high doping is often believed to be governed by conventional mean-field Bardeen-Cooper-Schrieffer theory1. However, it was shown that the superfluid density vanishes when the transition temperature goes to zero2,3, in contradiction to expectations from Bardeen-Cooper-Schrieffer theory. Our scanning tunnelling spectroscopy measurements in the overdoped regime of the (Pb,Bi)2Sr2CuO6+δ high-temperature superconductor show that this is due to the emergence of nanoscale superconducting puddles in a metallic matrix4,5. Our measurements further reveal that this puddling is driven by gap filling instead of gap closing. The important implication is that it is not a diminishing pairing interaction that causes the breakdown of superconductivity. Unexpectedly, the measured gap-to-filling correlation also reveals that pair breaking by disorder does not play a dominant role and that the mechanism of superconductivity in overdoped cuprate superconductors is qualitatively different from conventional mean-field theory.
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Primary hemophagocytic lymphohistiocytosis (pHLH) is a rare immune disorder and hematopoietic stem cell transplan- tation (HSCT) is the only potentially curative treatment. Given the high pre-HSCT mortality of pHLH patients reported in the HLH-2004 study (17%), more regimens to effectively control the disease and form a bridge with HSCT are needed. We conducted a retrospective study of pHLH children treated by ruxolitinib (RUX)-based regimen. Generally, patients received RUX until HSCT or unacceptable toxic side-effect. Methylprednisolone and etoposide were added sequentially when the disease was suboptimally controlled. The primary end point was 1-year overall survival. Twenty-one pHLH patients (12 previously treated and 9 previously untreated) were included with a median follow-up of 1.4 years. At last follow-up, 17 (81.0%) patients were alive with a 1-year overall survival of 90.5% (95% confidence interval: 84.1-96.9). Within the first 8 weeks, all patients had an objective response, of which 19 (90.5%) achieved complete response (CR) and two (9.5%) achieved partial response (PR) as a best response. Seventeen (81.0%) patients received HSCT, of which 13 (76.5%) had CR, three (17.6%) had PR and one (5.9%) had disease reactivation at the time of HSCT. Fifteen (88.2) patients were alive post- HSCT. Notably, eight (38.1%) patients received zero doses of etoposide, suggesting the potential of RUX-based regimen to reduce chemotherapy intensity. Patients tolerated RUX-based regimen well and the most frequently observed adverse events were hematologic adverse events. Overall, RUX-based regimen was effective and safe and could be used as a bridge to HSCT for pHLH children.
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Transplante de Células-Tronco Hematopoéticas , Linfo-Histiocitose Hemofagocítica , Nitrilas , Pirazóis , Pirimidinas , Criança , Humanos , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/etiologia , Resultado do Tratamento , Estudos Retrospectivos , Etoposídeo/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Resposta Patológica CompletaRESUMO
The shot noise in tunneling experiments reflects the Poissonian nature of the tunneling process. The shot-noise power is proportional to both the magnitude of the current and the effective charge of the carrier. Shot-noise spectroscopy thus enables us, in principle, to determine the effective charge q of the charge carriers of that tunnel. This can be used to detect electron pairing in superconductors: In the normal state, the noise corresponds to single electron tunneling (q=1e), while in the paired state, the noise corresponds to q=2e. Here, we use a newly developed amplifier to reveal that in typical mesoscopic superconducting junctions, the shot noise does not reflect the signatures of pairing and instead stays at a level corresponding to q=1e. We show that transparency can control the shot noise, and this q=1e is due to the large number of tunneling channels with each having very low transparency. Our results indicate that in typical mesoscopic superconducting junctions, one should expect q=1e noise and lead to design guidelines for junctions that allow the detection of electron pairing.
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Gene therapy is one of the strategies that may reduce or reverse progressive neurodegeneration in retinal neurodegenerative diseases. However, efficiently delivering transgenes to retinal ganglion cells (RGCs) remains hard to achieve. In this study, we innovatively investigated transduction efficiency of adeno-associated virus (AAV)-PHP.eB in murine RGCs by retro-orbital venous sinus injection. Five doses of AAV-PHP.eB-EGFP were retro-orbitally injected in venous sinus in adult C57/BL6J mice. Two weeks after administration, RGCs transduction efficiency was quantified by retinal flat-mounts and frozen section co-labeling with RGCs marker Rbpms. In addition, safety of this method was evaluated by RGCs survival rate and retinal morphology. To conform efficacy of this new method, AAV-PHP.eB-CNTF was administrated into mature mice through single retro-orbital venous injection after optic nerve crush injury to evaluate axonal elongation. Results indicated that AAV- PHP.eB readily crossed the blood-retina barrier and was able to transduce more than 90% of RGCs when total dose of virus reached 5 × 1010 vector genomes (vg). Moreover, this technique did not affect RGCs survival rate and retinal morphology. Furthermore, retro-orbital venous delivery of AAV-PHP.eB-CNTF effectively transduced RGCs, robustly promoted axonal regeneration after optic nerve crush injury. Thus, novel AAV-PHP.eB retro-orbital injection provides a minimally invasive and efficient route for transgene delivery in treatment of retinal neurodegenerative diseases.
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Dependovirus , Terapia Genética , Vetores Genéticos , Camundongos Endogâmicos C57BL , Células Ganglionares da Retina , Transdução Genética , Animais , Células Ganglionares da Retina/patologia , Células Ganglionares da Retina/metabolismo , Camundongos , Dependovirus/genética , Terapia Genética/métodos , Traumatismos do Nervo Óptico/terapia , Traumatismos do Nervo Óptico/metabolismo , Modelos Animais de Doenças , Sobrevivência Celular , Órbita/irrigação sanguíneaRESUMO
INTRODUCTION: Dimenhydrinate and scopolamine are frequently used drugs, but they cause drowsiness and performance decrement. Therefore, it is crucial to find peripheral targets and develop new drugs without central side effects. This study aimed to investigate the anti-motion sickness action and inner ear-related mechanisms of atrial natriuretic peptide (ANP). METHODS: Endolymph volume in the inner ear was measured with magnetic resonance imaging and expression of AQP2 and p-AQP2 was detected with Western blot analysis and immunofluorescence method. RESULTS: Both rotational stimulus and intraperitoneal arginine vasopressin (AVP) injection induced conditioned taste aversion (CTA) to 0.15% sodium saccharin solution and an increase in the endolymph volume of the inner ear. However, intraperitoneal injection of ANP effectively alleviated the CTA behaviour and reduced the increase in the endolymph volume after rotational stimulus. Intratympanic injection of ANP also inhibited rotational stimulus-induced CTA behaviour, but anantin peptide, an inhibitor of ANP receptor A (NPR-A), blocked this inhibitory effect of ANP. Both rotational stimulus and intraperitoneal AVP injection increased the expression of AQP2 and p-AQP2 in the inner ear of rats, but these increases were blunted by ANP injection. In in vitro experiments, ANP addition decreased AVP-induced increases in the expression and phosphorylation of AQP2 in cultured endolymphatic sac epithelial cells. CONCLUSION: Therefore, the present study suggests that ANP could alleviate motion sickness through regulating endolymph volume of the inner ear increased by AVP, and this action of ANP is potentially mediated by activating NPR-A and antagonising the increasing effect of AVP on AQP2 expression and phosphorylation.
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Arginina Vasopressina , Fator Natriurético Atrial , Endolinfa , Enjoo devido ao Movimento , Animais , Fator Natriurético Atrial/farmacologia , Fator Natriurético Atrial/metabolismo , Fator Natriurético Atrial/administração & dosagem , Arginina Vasopressina/farmacologia , Arginina Vasopressina/administração & dosagem , Arginina Vasopressina/metabolismo , Enjoo devido ao Movimento/tratamento farmacológico , Masculino , Endolinfa/efeitos dos fármacos , Endolinfa/metabolismo , Orelha Interna/efeitos dos fármacos , Ratos Sprague-Dawley , Aquaporina 2/metabolismo , RatosRESUMO
BACKGROUND: The patients with multisystem and risk organ involvement Langerhans cell histiocytosis (MS-RO + LCH) have poor prognosis. The patients with MS-LCH who failed front-line therapy have a high mortality rate and the standard salvage treatment has not been established. The combination of cytarabine (Ara-c), vincristine (VCR) and prednisone might be effective for refractory/relapse MS-RO + LCH, with low toxicity. METHODS: We retrospectively analyzed pediatric refractory/relapse MS-RO + LCH patients treated with the low-dose Ara-c (100mg/m2/d×5days) or high-dose Ara-c (500mg/m2/d×5days) combined with vindesine (VDS) and prednisone in a single center. The efficacy, outcomes and adverse events were analyzed. RESULTS: From January 2013 to December 2016, 13 patients receiving the low-dose Ara-c chemotherapy (LAC) and 7 patients receiving the high-dose Ara-c chemotherapy (HAC) were included in the study. 11 (84.6%) of the 13 patients treated with the LAC regimen and 6 (85.7%) of the 7 patients treated with the HAC regimen had response after four courses of the therapy. All patients in the study were alive during follow-up and the 3-year event-free survival rate (EFS) was 53.7% and 85.7% in the LAC and HAC groups. The most frequent adverse event was Grade 1/2 myelosuppression, which was observed in 38.5% (5/13) and 42.9% (3/7) of the patients receiving the LAC and HAC regimen. CONCLUSIONS: A combination of Ara-c, VDS and prednisone was effective and safe for some patients with refractory/relapse MS-RO + LCH. The high-dose Ara-c regimen was associated with a numerically higher EFS rate.
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Citarabina , Histiocitose de Células de Langerhans , Criança , Humanos , Citarabina/efeitos adversos , Prednisona/efeitos adversos , Vindesina/uso terapêutico , Estudos Retrospectivos , Histiocitose de Células de Langerhans/tratamento farmacológico , Histiocitose de Células de Langerhans/induzido quimicamente , Recidiva , Resultado do TratamentoRESUMO
Behavioural thermoregulation (thermotaxis) is essential for soil invertebrates to evade thermal extremes in terrestrial environments. Extensive and continuous use of copper (Cu) based products has led to elevated Cu concentration in soils across the globe and in some areas reaching concentrations that are hazardous to soil invertebrates. We hypothesised that environmental stressors, for example, exposure to heavy metals may compromise the adaptive behavioural thermoregulation of organisms, but very little is known of such interactions. In this study, we chose Cu as a model toxicant and investigated the potential effect of Cu-contaminated soils on the behavioural thermoregulation of springtails (Folsomia candida). We measured the distribution of springtails when placed on a temperature gradient ranging from 6 to 46 °C and estimated their thermal preference as an indicator of behavioural thermoregulation. Results showed that within 60 min of being introduced to the thermal gradient, the distribution of springtails was unimodal with slight skewness towards high temperature. Springtails exhibited a consistent preferred temperature range of approximately 21-23 °C across all Cu exposure levels and time points. However, Cu contamination increased the frequency of springtails recorded along the gradient where temperature was above 30 °C. We interpreted this observation as Cu-exposed animals having an elevated risk of entering heat coma and not being able to evade noxious temperatures. We conclude that Cu contamination does not alter the thermal preference of F. candida but compromises their ability to tolerate extreme high temperature. Incorporating behavioural responses into ecotoxicological assessments provides ecologically relevant insights into the impacts of chemical pollution on soil ecosystems.
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In the context of China's dual carbon target, reducing personal carbon emissions has been identified as a crucial strategy to achieve the target. The 2022 Digital China Development Report emphasizes the significance of implementing the Carbon Generalized System of Preferences (CGSP) in driving individual carbon reduction efforts in China. However, the psychological factors influencing public participation in CGSP are still unknown. Based on the Extended Theory of Planned Behavior (TPB), this study explored the psychological factors of different personality trait groups' participation in the CGSP and categorized 712 respondents into Compatible, Positive, Responsible, and Susceptible based on the MINI-IPIP scale and the K-means method. The results show that the strength of willingness to engage (WTE) in CGSP was ranked as: Compatible > Positive > Responsible > Susceptible and the WTE of compatible groups is more influenced by attitude, while Perceived Behavioral Control (PBC) plays a more crucial role in other groups. Personal Norms (PN) and Policy Awareness (PA) were significant for all specific personality groups except the Susceptible group. Surprisingly subjective norms had little to do with WTE. We believe that policymakers should consider the impact of PBC on WTE when formulating policies and raise the expectation of residents in terms of the value they can obtain from participating in CGSP. Additionally, promotional activities related to PN and PA in connection with CGSP should be conducted. These efforts may help individuals better engage in CGSP.
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Personalidade , Humanos , China , Atitude , Carbono , Teoria Psicológica , Teoria do Comportamento PlanejadoRESUMO
The aim of this study was to investigate the functional mechanism of Wuniuzao dark tea polysaccharide (WDTP) that protect against hyperlipidemia in mice induced by high-fat diet. WDTP was extracted by hot water, isolated and purified by DEAE-52 chromatography and characterized by high-performance liquid chromatograph (HPLC), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). Different doses (200 or 800 mg/kg/day) of WDTP were orally administered to mice induced by high-fat diet to evaluate the mechanism of WDTP regulating lipid metabolism. And these results showed that average molecular weight of WDTP was nearly 63,869 Da. And WDTP intervention significantly reduced body weight, lipid accumulation, and modulated blood lipid levels. The mechanism of WDTP ameliorating lipid metabolism was associated with regulating the expression of lipid metabolism-related genes and serum exosomes miR-19b-3p, and modulating the community structure of gut microbiota in mice.
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Hiperlipidemias , Metabolismo dos Lipídeos , Camundongos , Animais , Chá/química , Dieta Hiperlipídica/efeitos adversos , Espectroscopia de Infravermelho com Transformada de Fourier , Hiperlipidemias/tratamento farmacológico , Lipídeos , Camundongos Endogâmicos C57BLRESUMO
The construction of acyclic, non-adjacent 1,3-stereogenic centers, prevalent motifs in drugs and bioactive molecules, has been a long-standing synthetic challenge due to acyclic nucleophiles being distant from the chiral environment. In this study, we successfully synthesized highly valuable 1,2-bis(boronic) esters featuring acyclic and nonadjacent 1,3-stereocenters. Notably, this reaction selectively produces migratory coupling products rather than alternative deborylative allylation or direct allylation byproducts. This approach introduces a new activation mode for selective transformations of gem-diborylmethane in asymmetric catalysis. Additionally, we found that other gem-diborylalkanes, previously challenging due to steric hindrance, also successfully participated in this reaction. The incorporation of 1,2-bis(boryl)alkenes facilitated the diversification of the alkenyl and two boron moieties in our target compounds, thereby enabling access to a broad array of versatile molecules. DFT calculations were performed to elucidate the reaction mechanism and shed light on the factors responsible for the observed excellent enantioselectivity and diastereoselectivity. These were determined to arise from ligand-substrate steric repulsions in the syn-addition transition state.
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BACKGROUND: Although depression has been a serious neuropsychiatric disorder worldwide, current antidepressants used in clinical practice have various weaknesses, including delayed onset and low rates of efficacy. Recently, the development of new antidepressants from natural herbal medicine has become one of the important research hotspots. Cucurbitacin B is a natural compound widely distributed in the Cucurbitaceae and Cruciferae families and has many pharmacological activities. The present study aimed to investigate whether cucurbitacin B possess antidepressant-like effects in mice. METHODS: The antidepressant-like effects of cucurbitacin B on mice behaviors were explored using the forced swim test, tail suspension test, open field test, sucrose preference test, and a chronic unpredictable mild stress model of depression together. Then, western blotting and immunofluorescence were used to examine the effects of cucurbitacin B on the brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) signaling cascade and neurogenesis in the hippocampus of mice. Furthermore, BDNF-short hairpin RNA, K252a, and p-chlorophenylalanine methyl ester were adopted together to determine the antidepressant mechanism of cucurbitacin B. RESULTS: It was found that administration of cucurbitacin B indeed produced notable antidepressant-like effects in mice, which were accompanied with significant promotion in both the hippocampal BDNF-TrkB pathway and neurogenesis. The antidepressant mechanism of cucurbitacin B involves the hippocampal BDNF-TrkB system but not the serotonin system. CONCLUSIONS: Cucurbitacin B has the potential to be a novel antidepressant candidate.
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Antidepressivos , Fator Neurotrófico Derivado do Encéfalo , Depressão , Animais , Humanos , Camundongos , Antidepressivos/farmacologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Depressão/tratamento farmacológico , Depressão/metabolismo , Modelos Animais de Doenças , Hipocampo , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/metabolismoRESUMO
The fluorescence of functional dyes was generally quenched in aqueous solution, which hindered their application in water-bearing detections. In this work, a novel strategy based on host-guest interaction was provided for the purpose of fluorescence enhancement in aqueous solution and cell imaging. Three adamantane-modified fluorescent dyes (Coum-Ad, NP-Ad, NR-Ad) with coumarin, 1,8-naphthalimide and Nile Red as fluorophores were initially designed and prepared. The ((adamantan-1-yl)methyl)amino group, as the auxochrome of those dyes, complexed with methylated ß-cyclodextrin (M-ß-CD) via supramolecular interaction, and then fluorescent supramolecular nanoparticles (FSNPs) were formed by self-assembly in water. The inclusion equilibrium constant (K) could be as high as 3.94×104 â M-1 . With the addition of M-ß-CD, fluorescence quantum yields of these dyes were separately improved to 69.8 %, 32.9 % and 41.3 %. Inspired by the above satisfactory results, six adamantane-modified probes organelle-NPAds with organelle-targeting capability were further obtained. As the formation of hydrogen bonds between organelle-NPAd2 and M-ß-CD verified by theoretical calculation, K of organelle-NPAd2 (5.13×104 â M-1 ~4.53×105 â M-1 ) with M-ß-CD was higher than that of organelle-NPAd1 (1.15×104 â M-1 ~3.66×104 â M-1 ) and their fluorescence quantum yields increased to 32.8 %~83.6 % in aqueous solution. In addition, fluorescence enhancement was realized in cell imaging with the addition of M-ß-CD.
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Adamantano , beta-Ciclodextrinas , Adamantano/química , beta-Ciclodextrinas/química , Corantes Fluorescentes/química , Água/químicaRESUMO
T-cell acute lymphoblastic leukemia (T-ALL) has a poor prognosis as a result of severe immunosuppression and rapid tumor progression with resistance to conventional chemotherapy. Excessive IgD may play a role in T cell activation via IgD Fc receptor (FcδR). Here we aimed to investigate the effects of IgD in T-ALL and demonstrated the potential benefit by targeting IgD/FcδR in T-ALL patients with IgD-Fc-Ig fusion protein. In T-ALL patients' blood samples and cell lines, the level of IgD, the percentage of FcδR expressing cells and the binding affinity were determined by flow cytometry. T cell viability, proliferation and apoptosis were analyzed. A mouse xenograft model was used to evaluate the in vivo effect of IgD-Fc-Ig, an IgD-FcδR blocker. The levels of serum IgD and FcδR were abnormally increased in part of T-ALL patients and IgD could induce over-proliferation and inhibit apoptosis of T-ALL cells in vitro. FcδR was constitutively expressed on T-ALL cells. IgD-Fc-Ig showed similar binding affinity to FcδR and selectively blocked the stimulation effect of IgD on T-ALL cells in vitro. In vivo study exhibited that IgD-Fc-Ig may also have therapeutic benefit. IgD-Fc-Ig administration inhibited human T-ALL growth and extended survival in xenograft T-ALL mice. In conclusion, this work supports the idea of targeting IgD/FcδR in T-ALL patients with excessive IgD. IgD-Fc-Ig fusion protein might be a potential biological drug with high selectivity for T-ALL treatment.
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Linfócitos B , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Camundongos , Animais , Imunoglobulina D/fisiologia , Linfócitos TRESUMO
A series of viscosity probes targeting different organelles were obtained using a single hemicyanine dye as the matrix structure. Specifically, probes 1a-d were obtained by introducing four amines (6-amino-2H-chromen-2-one, N-(2-aminoethyl)-4-methylbenzenesulfonamide, dodecan-1-amine and N,N diphenylbenzene-1,4-diamine) into the indole hemicyanine dye of the carboxylic acid with a D-π-A structure. Their maximum absorption wavelengths were in the range 570-586 nm and they had relatively large molar absorption coefficients, while their maximum emission wavelengths in the red light region were in the range 596-611 nm. Moreover, their fluorescence intensity in glycerol was 35-184 times higher than that in phosphate buffer solution (PBS). The lg(Fl) and lg η of probes 1a-d showed good linearity with high correlation coefficients according to the Förster-Hoffman equation. In addition, cell staining experiments demonstrated that 1a-c could target lysosomes, endoplasmic reticulum and mitochondria, respectively. They could also undergo viscosity-detectable changes in the corresponding organelles under the action of the corresponding ion carriers.
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Corantes Fluorescentes , Organelas , Corantes Fluorescentes/química , Viscosidade , Lisossomos/químicaRESUMO
As an alkaloid, quinazolinone exhibits excellent biological properties; structurally, it also has the potential to construct fluorescent probes with conjugated structures. In this work, probes 5a-c and 6b were obtained by introducing quinazolone into aldehydes with different numbers of double bonds. Their absorption maxima were located at 420-540 nm and their emission maxima were at 500-600 nm in solvents of different polarities. In particular, probe 5c showed significant fluorescence enhancement with the increase in viscosity due to the limited intramolecular rotation, and its fluorescence intensity in glycerol was 37.8 times higher than that in water. Moreover, probes 5a-c and 6b containing the NH structure showed sensitive response to pH, and their fluorescence intensity in alkaline solution (pH 9-11) was suddenly enhanced, which was elucidated with the help of theoretical calculation. In addition, the cell experiments showed that probes 5a and 5b had the ability to target mitochondria and probes 5c and 6b targeted lysosomes in HeLa cells. Furthermore, the viscosity-sensitive probe 5c could be used for monitoring changes in lysosomal viscosity in HeLa cells, which had important guiding significance for designing multi-response fluorogenic probes and promoting the advancement of cancer diagnosis.
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Corantes Fluorescentes , Quinazolinonas , Humanos , Células HeLa , Quinazolinonas/análise , Corantes Fluorescentes/química , Lisossomos/química , Solventes , ViscosidadeRESUMO
To evaluate the contribution of host-guest chemistry in fluorescence enhancement under aqueous conditions, two benzo[a]phenoxazine derivatives with the adamantyl group were prepared. After they formed stable complexes with methyl-ß-cyclodextrin, their emissions at 625-825 nm were greatly increased and fluorescence quantum yields reached 11.5-12.6% in aqueous solution. Furthermore, they were successfully applied in fluorescence labeling of organelles in HeLa cells.
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Two chromenoquinoline-based fluorescent probes 1a-b have been synthesized and investigated. Photofading behaviors of compounds 1a-b showed that at least 89% absorption remained after 6 h irradiating, meanwhile, many of ions and amino acids had negligible impacts on their fluorescence intensity, which meant they had excellent photostability and selectivity. Probes 1a-b exhibited strong absorption and emission in organic solvents with large fluorescence quantum yields, even in water probe 1a still had a relatively large fluorescence quantum yield (20%). Combined with DFT calculation, the influence of alkylation on optical properties of 1b was elucidated. In addition, the fluorescence intensity of probe 1b with red emission enhanced by 5.4-fold and 5.3-fold after DNA and RNA added, and the fluorescence quantum yield increased from 3% to 17% and 14%, respectively, but the neutral molecule 1a had no response to nucleic acid. Furthermore, confocal microscopy imaging of probes 1a-b showed that 1a targeted lipid droplets while the methylated probe 1b to nucleus in living HeLa cells. The results indicated that the subcellular targeting zone could be changed by alkylation of nitrogen atom on chromenoquinoline-based conveniently, which provided a new idea for designing and synthesizing new subcellular labeled probes.