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1.
Chem Soc Rev ; 50(22): 12656-12678, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34633008

RESUMO

The twisted intramolecular charge transfer (TICT) mechanism has guided the development of numerous bright and sensitive fluorophores. This review briefly overviews the history of establishing the TICT mechanism, and systematically summarizes the molecular design strategies in modulating the TICT tendency of various organic fluorophores towards different applications, along with key milestone studies and representative examples. Additionally, we also succinctly review the twisted intramolecular charge shuttle (TICS) and twists during photoinduced electron transfer (PET), and compare their similarities and differences with TICT, with emphasis on understanding the structure-property relationships between the twisted geometries and how they can directly affect the fluorescence of the molecules. Such structure-property relationships presented herein will greatly aid the rational development of fluorophores that involve molecular twisting in the excited state.

2.
J Clin Invest ; 131(22)2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34609966

RESUMO

Ferroptosis, an iron-dependent nonapoptotic cell death, is a highly regulated tumor suppressing process. However, functions and mechanisms of RNA-binding proteins in regulation of evasion of ferroptosis during lung cancer progression are still largely unknown. Here, we report that the RNA-binding protein RBMS1 participates in lung cancer development via mediating ferroptosis evasion. Through an shRNA-mediated systematic screen, we discovered that RBMS1 is a key ferroptosis regulator. Clinically, RBMS1 was elevated in lung cancer and its high expression was associated with reduced patient survival. Conversely, depletion of RBMS1 inhibited lung cancer progression both in vivo and in vitro. Mechanistically, RBMS1 interacted with the translation initiation factor eIF3d directly to bridge the 3'- and 5'-UTR of SLC7A11. RBMS1 ablation inhibited the translation of SLC7A11, reduced SLC7A11-mediated cystine uptake, and promoted ferroptosis. In a drug screen that targeted RBMS1, we further uncovered that nortriptyline hydrochloride decreased the level of RBMS1, thereby promoting ferroptosis. Importantly, RBMS1 depletion or inhibition by nortriptyline hydrochloride sensitized radioresistant lung cancer cells to radiotherapy. Our findings established RBMS1 as a translational regulator of ferroptosis and a prognostic factor with therapeutic potential and clinical value.

3.
Angew Chem Int Ed Engl ; 60(47): 25104-25113, 2021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34519394

RESUMO

Although super-resolution imaging offers an opportunity to visualize cellular structures and organelles at the nanoscale level, cellular heterogeneity and unpredictability still pose a significant challenge in the dynamic imaging of live cells. It is thus vital to develop better-performing and more photostable probes for long-term super-resolution imaging. Herein, we report a probe, LD-FG, for imaging lipid droplet (LD) dynamics using structured illumination microscopy (SIM). LD-FG allows wash-free imaging of LDs, owing to a hydrogen-bond sensitive fluorogenic response. The replacement of photobleached LD-FG by intact probe molecules outside the LDs ensures the long-time stability of the fluorescence imaging. With this buffering fluorogenic probe, fast and unpredictable dynamic processes of LDs can be visualized. Using this probe, two LD coalescence modes were discovered. The dynamic imaging also allowed us to propose a new model of LD maturation during adipocyte differentiation, i.e., a fast LD coalescence followed by a slow ripening step. The excellent performance of LD-FG makes the buffer strategy an effective method for designing fluorescent probes for cell dynamic imaging.

4.
Anal Chem ; 93(10): 4542-4551, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33660993

RESUMO

Cell surface is the primary site for sensing extracellular stimuli. The knowledge of the transient changes on the surfaceome upon a perturbation is very important as the initial changed proteins could be driving molecules for some phenotype. In this study, we report a fast cell surface labeling strategy based on peroxidase-mediated oxidative tyrosine coupling strategy, enabling efficient and selective cell surface labeling within seconds. With a labeling time of 1 min, 2684 proteins, including 1370 (51%) cell surface-annotated proteins (cell surface/plasma membrane/extracellular), 732 transmembrane proteins, and 81 cluster of differentiation antigens, were identified from HeLa cells. By comparison with the negative control experiment using quantitative proteomics, 500 (68%) out of the 731 significantly enriched proteins (p-value < 0.05, ≥2-fold) in positive experimental samples were cell surface-annotated proteins. Finally, this technology was applied to track the dynamic changes of the surfaceome upon insulin stimulation at two time points (5 min and 2 h) in HepG2 cells. Thirty-two proteins, including INSR, CTNNB1, TFRC, IGF2R, and SORT1, were found to be significantly regulated (p-value < 0.01, ≥1.5-fold) after insulin exposure by different mechanisms. We envision that this technique could be a powerful tool to analyze the transient changes of the surfaceome with a good time resolution and to delineate the temporal and spatial regulation of cellular signaling.


Assuntos
Proteoma , Proteômica , Biotinilação , Membrana Celular/metabolismo , Células HeLa , Humanos , Proteoma/metabolismo
5.
Biosens Bioelectron ; 176: 112886, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33421760

RESUMO

Super-resolution fluorescence microscopy has emerged as a powerful tool for studying mitochondrial dynamics in living cells. However, the lack of photostable and chemstable probe makes long-term super-resolution imaging of mitochondria still a challenging work. Herein, we reported a 4-azetidinyl-naphthliamide derived SNAP-tag probe AN-BG exhibiting excellent fluorogenicity and photostability for long-term super-resolution imaging of mitochondrial dynamics. The azetidinyl group and naphthalimide fluorophore are in a flat conformation which can effectively suppress twisted intramolecular charge transfer and then effectively improve the brightness and photostability. This planarized molecular structure is conducive to the formation of fluorescence-quenched J-aggregates, and the protein labeling process will depolymerize the probes and restore fluorescence. Fluorescent labeling mitochondrial inner membrane proteins via SNAP tags overcomes the shortcomings that variations in mitochondrial inner membrane potential will release probes attached to mitochondria by electrostatic interactions. Therefore, AN-BG realized the stable labeling of mitochondria and the long-term imaging of mitochondrial dynamics under super-resolution microscopy.


Assuntos
Técnicas Biossensoriais , Dinâmica Mitocondrial , Corantes Fluorescentes , Microscopia de Fluorescência , Naftalimidas
6.
J Pharm Anal ; 10(5): 444-451, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33133728

RESUMO

The harm of pathogenic bacteria to humans has promoted extensive research on physiological processes of pathogens, such as the mechanism of bacterial infection, antibiotic mode of action, and bacterial antimicrobial resistance. Most of these processes can be better investigated by timely tracking of fluorophore-derived antibiotics in living cells. In this paper, we will review the recent development of fluorescent antibiotics featuring the conjugation with various fluorophores, and focus on their applications in fluorescent imaging and real-time detection for various physiological processes of bacteria in vivo.

7.
J Phys Chem B ; 124(34): 7467-7474, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32790386

RESUMO

Si-rhodamine has been extensively used in super-resolution fluorescence imaging in recent years. Its equilibrium between ring-closed nonfluorescent spirolactones and ring-opened fluorescent zwitterions endows Si-rhodamine with excellent fluorogenicity, membrane permeability, and photostability. In this paper, the equilibrium of Si-rhodamine between lactones and zwitterions was revealed to be greatly affected by various environmental factors, including molecular aggregation, solvent polarity, pH, metal ions, irradiation, and temperature. These environmental sensitivities make Si-rhodamine useful as a hydrochromic material, a fluorescent sensor array for metal ions or solvents, and a photoactivatable switch. Importantly, these results indicate that using Si-rhodamine as a fluorogenic probe or a blinking fluorophore in single-molecule localization super-resolution microscopy requires caution on possible false signals caused by its environmental sensitivity.

8.
Angew Chem Int Ed Engl ; 59(45): 20215-20223, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-32776641

RESUMO

Herein, we reported a simple, fast, and quantitative theoretical descriptor ΔGC-O that allows accurate predictions of a wide range of spontaneously blinking rhodamines. ΔGC-O denotes the Gibbs free energy differences between the closed and open forms of rhodamines and has a good linear relationship with experimental pKcycl values. This correlation affords an effective guide for the quantitative designs of spontaneously blinking rhodamines and eliminates trial-and-error. We have validated the predictive power of ΔGC-O via the development of two spontaneously blinking rhodamines of different colors and enhanced brightness. We also demonstrated their super-resolution imaging utilities in dynamic live-cell imaging. We expect that ΔGC-O will greatly facilitate the efficient creations of spontaneously blinking fluorophores and aid the advancements of super-resolution bioimaging techniques.


Assuntos
Rodaminas/metabolismo , Corantes Fluorescentes/metabolismo , Células HeLa , Humanos , Microscopia de Fluorescência/métodos
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 240: 118466, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32521444

RESUMO

The dye rhodamine, as the most popular scaffold to construct fluorescent labels and probes, has been explored extensively on its structure-fluorescence relationships. Particularly, the replacement of the oxygen atom in the 10th position with heteroatoms obtained various new rhodamines with improved photophysical properties, such as brightness, photostability, red-shifted emission and fluorogenicity. However, the applications of heteroatom-substituted rhodamines have been hindered by difficult synthetic routes. Herein, we explored the condensation strategy of diaryl ether analogues and o-tolualdehyde to synthesize various heteroatom-substituted rhodamines. We found that the electron property and steric effect in the rhodamine 10th position determined the synthetic yield. It's concluded that this condensation method was more suitable for the synthesis of heteroatom-substituted rhodamines with small or electron-donating groups like rhodamine, S-rhodamine and Si-rhodamine. We hope these results will benefit the design and synthesis of heteroatom-substituted rhodamines.

11.
J Am Chem Soc ; 142(14): 6777-6785, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32182060

RESUMO

Photoinduced electron transfer (PET) is one of the most important mechanisms for developing fluorescent probes and biosensors. Quantitative prediction of the quantum yields of these probes and sensors is crucial to accelerate the rational development of novel PET-based functional materials. Herein, we developed a general descriptor (ΔE) for predicting the quantum yield of PET probes, with a threshold value of ∼0.6 eV. When ΔE < ∼0.6 eV, the quantum yield is low (mostly <2%) due to the substantial activation of PET in polar environments; when ΔE > ∼0.6 eV, the quantum yield is high because of the inhibition of PET. This simple yet effective descriptor is applicable to a wide range of fluorophores, such as BODIPY, fluorescein, rhodamine, and Si-rhodamine. This ΔE descriptor enables us not only to establish new applications for existing PET probes but also to quantitatively design novel PET-based fluorophores for wash-free bioimaging and AIEgen development.

12.
ACS Sens ; 5(3): 731-739, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32072803

RESUMO

Viscosity in the intracellular microenvironment shows a significant difference in various organelles and is closely related to cellular processes. Such microviscosity in live cells is often mapped and quantified with fluorescent molecular rotors. To enable the rational design of viscosity-sensitive molecular rotors, it is critical to understand their working mechanisms. Herein, we systematically synthesized and investigated two sets of BODIPY-based molecular rotors to study the relationship between intramolecular motions and viscosity sensitivity. Through experimental and computational studies, two conformations (i.e., the planar and butterfly conformations) are found to commonly exist in BODIPY rotors. We demonstrate that the transformation energy barrier from the planar conformation to the butterfly conformation is strongly affected by the molecular structures of BODIPY rotors and plays a critical role in viscosity sensitivity. These findings enable rational structure modifications of BODIPY molecular rotors for highly effective protein detection and recognition.


Assuntos
Compostos de Boro/química , Corantes Fluorescentes/química , Sondas Moleculares , Movimento (Física) , Viscosidade
13.
Angew Chem Int Ed Engl ; 59(25): 10160-10172, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-31943591

RESUMO

Inhibition of TICT can significantly increase the brightness of fluorescent materials. Accurate prediction of TICT is thus critical for the quantitative design of high-performance fluorophores and AIEgens. TICT of 14 types of popular organic fluorophores were modeled with time-dependent density functional theory (TD-DFT). A reliable and generalizable computational approach for modeling TICT formations was established. To demonstrate the prediction power of our approach, we quantitatively designed a boron dipyrromethene (BODIPY)-based AIEgen which exhibits (almost) barrierless TICT rotations in monomers. Subsequent experiments validated our molecular design and showed that the aggregation of this compound turns on bright emissions with ca. 27-fold fluorescence enhancement, as TICT formation is inhibited in molecular aggregates.

14.
Chem Commun (Camb) ; 55(100): 15045-15048, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31782433

RESUMO

We reported fluorescent probes to image Zn2+ with plasma membrane-specific and Zn2+-specific fluorogenicities. The probes contained hydrophobic alkyl chains as membrane-anchored domains and hydrophilic zinc sensor ZTRS, and aggregated to display quenched fluorescence. Cells dissolved the aggregates and the liberated probes were dispersed on the outside of the cell plasma membrane. Aggregates that did not bind to the cell membrane still exhibited aggregation-induced fluorescence quenching after complexing with zinc ions, while probes anchored on the membrane surface exhibited a fluorescence-enhanced response upon recognition of zinc ions.


Assuntos
Membrana Celular/metabolismo , Corantes Fluorescentes/química , Zinco/química , Linhagem Celular Tumoral , Humanos , Íons/química , Microscopia Confocal
15.
Se Pu ; 37(8): 872-877, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642258

RESUMO

The visualization of the microcosmic behavior of proteins in vivo is the key to real-time monitoring of proteins. A series of wash-free SNAP-tag probes were designed and synthesized based on the combination of SNAP-tag and small organic molecule fluorescent dyes. SNAP-tag, which specifically recognized O6-benzylguanine, could be labeled with a fluorophore (e. g., 1,8-naphthalimide) through the formation of covalent bonds. Furthermore, the change from a hydrophilic environment to the hydrophobic cavum of SNAP-tag realized a 2-13-fold enhancement in fluorescence. Through the fusion of SNAP-tag and the target protein, the probes could recognize the mitochondrial proteins (e. g., cytochrome oxidase, Cox8A) and nuclear proteins (e. g., H2B) in living cells. Besides, the fluorescent probes allowed the in-situ real-time monitoring of proteins without washing.


Assuntos
Corantes Fluorescentes , Proteínas/química , Fluorescência
16.
Phys Chem Chem Phys ; 21(30): 16798-16803, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31329206

RESUMO

A deep understanding of fluorescence on-off and off-on switching mechanisms is the foundation for rationally designing highly effective molecular logic gate components and systems. These mechanisms, however, are often subtle to perceive and interpret, as multiple effects may contribute to the change of fluorescence signals. Herein, we systematically investigated the 'off-on-off' switching mechanisms of a fluorescent logic gate molecule M1 using density functional theory (DFT) and time-dependent DFT (TD-DFT). Based on photoexcitation and photoemission calculations, and potential energy surface scans in the excited state, we have shown that as the pH of the medium continuously decreases and the sequential protonation of the molecule takes place, the prevention of twisted intramolecular charge transfer (TICT) followed by the activation of photo-induced electron transfer (PET) was responsible for the off-on-off switching mechanism of M1. Our results provided new insights for understanding the 'off-on-off' phenomenon in M1. The good agreement between theoretical calculations and experimental observations also suggests that computational chemistry is a powerful tool to aid the molecular design and engineering of fluorescent logic gate compounds.

17.
Chem Sci ; 10(18): 4914-4922, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31160962

RESUMO

Rhodamine spirolactam based photoswitches have been extensively applied in super-resolution single-molecule localization microscopy (SMLM). However, the ring-opening reactions of spirolactams are cross-sensitive to acid, limiting their photoswitch use to neutral pH conditions. In addition, the ring-closing reactions of spirolactams are environment-sensitive and slow (up to hours), virtually making rhodamine spirolactams caged fluorescent dyes instead of reversible photoswitches in SMLM. Herein, by introducing hydrogen bonds to stabilize spirolactams, we report a series of acid-resistant rhodamine spirolactams with accelerated ring-closing reactions from fluorescent xanthyliums to non-fluorescent spirolactams, endowing them with good photoswitchable properties even in acidic environments. By further substitution of 6-phenylethynyl naphthalimide on the spirolactam, we shifted the photoactivation wavelength into the visible region (>400 nm). Subsequently, we have successfully applied these dyes in labeling and imaging the cell surface of Bacillus subtilis at pH 4.5 using SMLM.

18.
Angew Chem Int Ed Engl ; 58(21): 7073-7077, 2019 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-30916461

RESUMO

Charge transfer and separation are important processes governing numerous chemical reactions. Fundamental understanding of these processes and the underlying mechanisms is critical for photochemistry. Herein, we report the discovery of a new charge-transfer and separation process, namely the twisted intramolecular charge shuttle (TICS). In TICS systems, the donor and acceptor moieties dynamically switch roles in the excited state because of an approximately 90° intramolecular rotation. TICS systems thus exhibit charge shuttling. TICSs exist in several chemical families of fluorophores (such as coumarin, BODIPY, and oxygen/carbon/silicon-rhodamine), and could be utilized to construct functional fluorescent probes (i.e., viscosity- or biomolecule-sensing probes). The discovery of the TICS process expands the current perspectives of charge-transfer processes and will inspire future applications.

19.
J Proteomics ; 196: 33-41, 2019 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-30707948

RESUMO

Cell surface proteins are responsible for many critical functions. Systematical profiling of these proteins would provide a unique molecular fingerprint to classify cells and provide important information to guide immunotherapy. Cell surface biotinylation method is one of the effective methods for cell surface proteome profiling. However, classical workflows suffer the disadvantage of poor sensitivity. In this work, we presented an optimized protocol which enabled identification of more cell surface proteins from a smaller number of cells. When this protocol was combined with a tip based fractionation scheme, 4510 proteins, including 2055 annotated cell surface-associated proteins, were identified with only 20 microgram protein digest, showing the superior sensitivity of the approach. To enable process 10 times fewer cells, a pipet tip based protocol was developed, which led to the identification of about 600 cell surface-associated proteins. Finally, the new protocol was applied to compare the cell surface proteomes of two breast cancer cell lines, BT474 and MCF7. It was found that many cell surface-associated proteins were differentially expressed. The new protocols were demonstrated to be easy to perform, time-saving, and yielding good selectivity and high sensitivity. We expect this protocol would have broad applications in the future. SIGNIFICANCE: Cell surface proteins confer specific cellular functions and are easily accessible. They are often used as drug targets and potential biomarkers for prognostic or diagnostic purposes. Thus, efficient methods for profiling cell surface proteins are highly demanded. Cell surface biotinylation method is one of the effective methods for cell surface proteome profiling. However, classical workflows suffer the disadvantage of poor sensitivity. In this work, we presented an optimized protocol which enabled identification of more cell surface proteins from a smaller number of starting cells. The new protocol is easier to perform, time-saving and has less protein loss. By using a special pipet tip, sensitive and in-depth cell surface proteome analysis could be achieved. In combination with label-free quantitative MS, the new protocol can be applied to the differential analysis of the cell surface proteomes between different cell lines to find genetically- or drug-induced changes. We expect this protocol would have broad application in cell surface protein studies, including the discovery of diagnostic marker proteins and potential therapeutic targets.


Assuntos
Perfilação da Expressão Gênica , Proteínas de Membrana/metabolismo , Proteoma/metabolismo , Proteômica , Biomarcadores/metabolismo , Biotinilação , Linhagem Celular , Humanos
20.
ACS Sens ; 4(2): 281-285, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30672274

RESUMO

An imidazolium-derived pyrene aggregation was developed to rapidly identify and quantify different bacteria species. When the nonemissive aggregates bound to the anionic bacteria surface, the sensor disassembled to turn on significant fluorescence. At the same time, ratiometric signals between pyrene monomer and excimer emission were controlled by different interactions with various bacteria surfaces. The resulted different fluorescent emission profiles then were obtained as fingerprints for various bacterial species. By converting emission profiles directly into output signals of two channels, fluorescence increase and ratiometric change, a two-dimensional analysis map was generated for bacteria identification. We demonstrated that our sensor rapidly identified 10 species of bacteria and 14 clinical isolated multidrug-resistant bacteria, and we determined their staining properties (Gram-positive or Gram-negative).


Assuntos
Bactérias/isolamento & purificação , Membranas Artificiais , Pirenos/química , Espectrometria de Fluorescência/instrumentação , Imidazóis/química , Cinética
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