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Chembiochem : a European Journal of... Feb 2019The brain's astrocytes play key roles in normal and pathological brain processes. Targeting small molecules to astrocytes in the presence of the many other cell types in...
The brain's astrocytes play key roles in normal and pathological brain processes. Targeting small molecules to astrocytes in the presence of the many other cell types in the brain will provide useful tools for their visualization and manipulation. Herein, we explore the functional consequences of synthetic modifications to a recently described astrocyte marker composed of a bright rhodamine-based fluorophore and an astrocyte-targeting moiety. We altered the nature of the targeting moiety to probe the dependence of astrocyte targeting on hydrophobicity, charge, and pK when exposed to astrocytes and neurons isolated from the mouse cortex. We found that an overall molecular charge of +2 and a targeting moiety with a heterocyclic aromatic amine are important requirements for specific and robust astrocyte labeling. These results provide a basis for engineering astrocyte-targeted molecular tools with unique properties, including metabolite sensing or optogenetic control.
Topics: Animals; Astrocytes; Cerebral Cortex; Mice; Molecular Probes; Neurons; Optical Imaging; Rhodamines
PubMed: 30419144
DOI: 10.1002/cbic.201800692 -
Spectrochimica Acta. Part A, Molecular... Dec 2023The present investigation highlights a quinoline-based small molecule probe (DEQ) for the detection of Cd among other metal ions in near-aqueous media. The probe DEQ and...
The present investigation highlights a quinoline-based small molecule probe (DEQ) for the detection of Cd among other metal ions in near-aqueous media. The probe DEQ and its Cd complex (DEQ-Cd) have been synthesized and characterized by all possible spectroscopic methods. The weakly emissive DEQ showed its strong emission in the presence of Cd, which is attributed to the photoinduced electron transfer (PET) along with the chelation-enhanced fluorescence (CHEF) mechanism. The 1:1 binding mode between ligand and Cd is confirmed by single crystal XRD analysis, which is further supported by Job's plot and HRMS. The detection limit of the probe to recognize Cd was found to be as low as 89 nM. Furthermore, DEQ can act as a reversible fluorescence probe with the off-on-off mechanism by the alternative addition of Cd and EDTA. DFT and TD-DFT studies exposed the proposed mechanism after Cd insertion and the obtained results for electronic spectra are in line with the experimental results. The response towards pH was quite interesting and allowed us to study its application in live cell imaging. With all the positive results, the proposed ligand DEQ can be used as a potential probe for the detection of Cd in real-life applications.
Topics: Molecular Probes; Cadmium; Spectrometry, Fluorescence; Ligands; Fluorescent Dyes; Optical Imaging
PubMed: 37429195
DOI: 10.1016/j.saa.2023.123098 -
Current Opinion in Chemical Biology Feb 2015MicroRNAs (miRNAs) are small, non-coding RNAs that control protein expression. Aberrant miRNA expression has been linked to various human diseases, and thus miRNAs have... (Review)
Review
MicroRNAs (miRNAs) are small, non-coding RNAs that control protein expression. Aberrant miRNA expression has been linked to various human diseases, and thus miRNAs have been explored as diagnostic markers and therapeutic targets. Although it is challenging to target RNA with small molecules in general, there have been successful campaigns that have identified small molecule modulators of miRNA function by targeting various pathways. For example, small molecules that modulate transcription and target nuclease processing sites in miRNA precursors have been identified. Herein, we describe challenges in developing chemical probes that target miRNAs and highlight aspects of miRNA cellular biology elucidated by using small molecule chemical probes. We expect that this area will expand dramatically in the near future as progress is made in understanding small molecule recognition of RNA.
Topics: Animals; Base Sequence; Drug Discovery; Humans; MicroRNAs; Molecular Probe Techniques; Molecular Probes; Molecular Sequence Data; Small Molecule Libraries; Transcriptional Activation
PubMed: 25500006
DOI: 10.1016/j.cbpa.2014.10.024 -
Contrast Media & Molecular Imaging Nov 2016Nowadays molecular imaging plays a vital role in achieving a successful targeted and personalized treatment. Hence, the approach of combining two or more medical imaging... (Review)
Review
Nowadays molecular imaging plays a vital role in achieving a successful targeted and personalized treatment. Hence, the approach of combining two or more medical imaging modalities was developed. The objective of this review is to systematically compare recent dual contrast agents in Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI) and in some cases Single photon emission computed tomography (SPECT)/MRI in terms of some their characteristics, such as tumor uptake, and reticuloendothelial system uptake (especially liver) and their relaxivity rates for early detection of primary cancer tumor. To the best of our knowledge, this is the first systematic and integrated overview of this field. Two reviewers individually directed the systematic review search using PubMed, MEDLINE and Google Scholar. Two other reviewers directed quality assessment, using the criteria checklist from the CAMARADES (Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies) tool, and differences were resolved by consensus. After reviewing all 49 studies, we concluded that a size range of 20-200 nm can be used for molecular imaging, although it is better to try to achieve as small a size as it is possible. Also, small nanoparticles with a hydrophilic coating and positive charge are suitable as a T contrast agent. According to our selected data, the most successful dual probes in terms of high targeting were with an average size of 40 nm, PEGylated using peptides as a biomarker and radiolabeled with copper 64 and gallium 68. Copyright © 2017 John Wiley & Sons, Ltd.
Topics: Animals; Contrast Media; Humans; Magnetic Resonance Imaging; Molecular Probes; Multimodal Imaging; Nanoparticles; Positron-Emission Tomography; Radioisotopes; Tomography, Emission-Computed, Single-Photon
PubMed: 28102031
DOI: 10.1002/cmmi.1719 -
BMC Bioinformatics Jun 2019DNA is a promising candidate for the construction of biological devices due to its unique properties, including structural simplicity, convenient synthesis, high...
BACKGROUND
DNA is a promising candidate for the construction of biological devices due to its unique properties, including structural simplicity, convenient synthesis, high flexibility, and predictable behavior. And DNA has been widely used to construct the advanced logic devices.
RESULTS
Herein, a molecular probe apparatus was constructed based on DNA molecular computing to perform fluorescent quenching and fluorescent signal recovery, with an ' ON/OFF' switching function. In this study, firstly, we program the streptavidin-mediated fluorescent quenching apparatus based on short-distance strand migration. The variation of fluorescent signal is acted as output. Then DNAzyme as a switching controller was involved to regulate the fluorescent signal increase. Finally, on this base, a cascade DNA logic gate consists of two logic AND operations was developed to enrich probe machine.
CONCLUSION
The designed probe computing model can be implemented with readout of fluorescence intensity, and exhibits great potential applications in the field of bioimaging as well as disease diagnosis.
Topics: Computer Simulation; DNA; DNA, Catalytic; Fluorescence; Logic; Molecular Probes; Signal Processing, Computer-Assisted; Streptavidin
PubMed: 31182004
DOI: 10.1186/s12859-019-2767-8 -
Chembiochem : a European Journal of... Jan 2021Bcl-2 and Mcl-1, the two arms of the anti-apoptotic Bcl-2 family proteins, have been identified as key regulators of apoptosis and effective therapeutic targets of...
Bcl-2 and Mcl-1, the two arms of the anti-apoptotic Bcl-2 family proteins, have been identified as key regulators of apoptosis and effective therapeutic targets of cancer. However, no small-molecular probe is capable of profiling and visualizing both Bcl-2 and Mcl-1 simultaneously in situ. Herein, we report a multifunctional molecular probe (BnN -OPD-Alk) by a "three-in-one" molecular designing strategy, which integrated the Bcl-2/Mcl-1 binding ligand, fluorescent reporter group and photoreactive group azido into the same scaffold. BnN -OPD-Alk exhibited sub-micromolar affinities to Bcl-2/Mcl-1 and bright green self-fluorescence. It was then successfully applied for Bcl-2/Mcl-1 labeling, capturing, enriching, and bioimaging both in vitro and in cells. This strategy could facilitate the precise early diagnosis and effective therapy of dual Bcl-2/Mcl-1-related diseases.
Topics: Fluorescence; Humans; Molecular Probes; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Optical Imaging; Proto-Oncogene Proteins c-bcl-2
PubMed: 32881291
DOI: 10.1002/cbic.202000441 -
World Journal of Gastroenterology Jun 2019Hepatocellular carcinoma (HCC) ranks second in terms of cancer mortality worldwide. Molecular magnetic resonance imaging (MRI) targeting HCC biomarkers such as...
BACKGROUND
Hepatocellular carcinoma (HCC) ranks second in terms of cancer mortality worldwide. Molecular magnetic resonance imaging (MRI) targeting HCC biomarkers such as alpha-fetoprotein (AFP) or glypican-3 (GPC3) offers new strategies to enhance specificity and help early diagnosis of HCC. However, the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3, which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors < 1 cm (MHCC). We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.
AIM
To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.
METHODS
A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3 (UAG) was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle (USPIO). At the same time, the singly labeled probes of anti-AFP-USPIO (UA) and anti-GPC3-USPIO (UG) and non-targeted USPIO (U) were also prepared for comparison. The physical characterization including morphology (transmission electron microscopy), hydrodynamic size, and zeta potential (dynamic light scattering) was conducted for each of the probes. The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3. First, AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry. Then, the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and MRI (T2-weighted and T2-map) with a 3.0 Tesla clinical MR scanner.
RESULTS
Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens compared with single antibody-conjugated and unconjugated USPIO probes. The iron Prussian blue staining and quantitative T2-map MRI analysis showed that, compared with UA, UG, and U, the uptake of double antigen-targeted UAG probe demonstrated a 23.3% ( UA), 15.4% ( UG), and 57.3% ( U) increased Prussian stained cell percentage and a 14.93% ( UA), 9.38% ( UG), and 15.3% ( U) reduction of T2 relaxation time, respectively. Such bi-specific probe might have the potential to overcome tumor heterogeneity. Meanwhile, the coupling of two antibodies did not influence the magnetic performance of USPIO, and the relatively small hydrodynamic size (59.60 ± 1.87 nm) of double antibody-conjugated USPIO probe makes it a viable candidate for use in MHCC MRI , as they are slowly phagocytosed by macrophages.
CONCLUSION
The bi-specific probe presents enhanced targeting efficiency and MRI sensitivity to HCC cells than singly- or non-targeted USPIO, paving the way for translation to further evaluate its clinical potential.
Topics: Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Dextrans; Early Detection of Cancer; Glypicans; Immunoconjugates; Liver Neoplasms; Magnetic Resonance Imaging; Magnetite Nanoparticles; Mice; Molecular Probes
PubMed: 31293339
DOI: 10.3748/wjg.v25.i24.3030 -
Chemistry (Weinheim An Der Bergstrasse,... Jan 2021Positron emission tomography (PET)-fluorescence imaging is an emerging field of multimodality imaging seeking to attain synergy between the two techniques. The probes... (Review)
Review
Positron emission tomography (PET)-fluorescence imaging is an emerging field of multimodality imaging seeking to attain synergy between the two techniques. The probes employed in PET-fluorescence imaging incorporate both a fluorophore and radioisotope which enable complementary information to be obtained from both imaging techniques via the administration of a single agent. Fluorine-18 is the most commonly used radioisotope in PET imaging and consequently many novel attempts to radiofluorinate various fluorophores have transpired over the past decade. In this Minireview, the most relevant fluorine-18 labelled PET-fluorescence probes have been classified into four groups as per the implemented fluorophore: 1) boron-dipyrromethene (BODIPY) dyes, 2) cyanine dyes, 3) alternative organic fluorophores and 4) organometallics, such as quantum dots (QDs) and rhenium complexes. The biological, radiochemical and photophysical properties of each probe have been systematically compared to aid future endeavours in PET-fluorescence chemistry.
Topics: Fluorescence; Fluorescent Dyes; Fluorine Radioisotopes; Molecular Probes; Positron-Emission Tomography
PubMed: 32697376
DOI: 10.1002/chem.202001402 -
Bioorganic & Medicinal Chemistry Jan 2021The ability to incorporate a desired functionality into proteins of interest in a site-specific manner can provide powerful tools for investigating biological systems...
The ability to incorporate a desired functionality into proteins of interest in a site-specific manner can provide powerful tools for investigating biological systems and creating therapeutic conjugates. However, there are not any universal methods that can be applied to all proteins, and it is thus important to explore the chemical strategy for protein modification. In this paper, we developed a new reactive peptide tag/probe pair system for site-specific covalent protein labeling. This method relies on the recognition-driven reaction of a peptide tag and a molecular probe, which comprises the lysine-containing short histidine tag (KH6 or H6K) and a binuclear nickel (II)- nitrilotriacetic acid (Ni-NTA) complex probe containing a lysine-reactive N-acyl-N-alkyl sulfonamide (NASA) group. The selective interaction of the His-tag and Ni-NTA propeles a rapid nucleophilic reaction between a lysine residue of the tag and the electrophilic NASA group of the probe by the proximity effect, resulting in the tag-site-specific functionalization of proteins. We characterized the reactive profile and site-specificity of this method using model peptides and proteins in vitro, and demonstrated the general utility for production of a nanobody-chemical probe conjugate without compromising its binding ability.
Topics: HEK293 Cells; Histidine; Humans; Indicators and Reagents; Lysine; Models, Molecular; Molecular Probes; Molecular Structure; Nickel; Nitrilotriacetic Acid; Proteins; Staining and Labeling; Sulfonamides
PubMed: 33360195
DOI: 10.1016/j.bmc.2020.115947 -
Nano Letters Jan 2022The deep penetration, real-time monitoring ability, and high resolution of near-infrared (NIR) fluorescence imaging make it suitable for tumor diagnosis. However, the...
The deep penetration, real-time monitoring ability, and high resolution of near-infrared (NIR) fluorescence imaging make it suitable for tumor diagnosis. However, the lack of specificity and selectivity restricts its further application. Here, for the first time, we applied a CBT-Cys click condensation reaction to synthesize an acidity-initiated molecular probe (AIM-Probe, Cys(StBu)-Lys(Cy 5.5)-EDA-PMA-CBT), which could self-assemble into nanoparticles (AIM-NP) with self-quenched fluorescence under glutathione (GSH) reduction. AIM-NP could accumulate in tumors after intravenous injection. Subsequently, the EDA-PMA part of AIM-Probe in AIM-NP is fractured by the unique subacid condition in the tumor microenvironment, and AIM-NP disassembles into a small AIM-cleaved molecule (PMA-CBT-Cys-Lys(Cy5.5)-EDA) along with fluorescence switching on. As a result, AIM-NP could switch on fluorescence at the tumor site, thereby achieving tumor-targeted imaging. To our knowledge, utilizing tumor acidity to initiate the disassembly of self-assembled nanoparticles through a CBT-Cys click condensation reaction has not been reported.
Topics: Fluorescence; Fluorescent Dyes; Humans; Molecular Probes; Nanoparticles; Neoplasms; Optical Imaging; Tumor Microenvironment
PubMed: 34958593
DOI: 10.1021/acs.nanolett.1c03534