Language：English   Publishing type：Research paper (scientific journal)  

Deuterated molecules are of growing interest because of the specific characteristics of deuterium, such as stronger C-D bonds being stronger than C-H bonds. Polyethylene glycols (PEGs) are widely utilized in scientific fields (e. g., drug discovery and material sciences) as linkers and for the improvement of various properties (solubility in water, stability, etc.) of mother compounds. Therefore, deuterated PEGs can be used as novel tools for drug discovery. Although the H/D exchange reaction (deuteration) is a powerful and straightforward method to produce deuterated compounds, the deuteration of PEGs bearing many unactivated C(sp3)-H bonds has not been developed. Herein, we report the photocatalytic deuteration of multiple sites of PEGs using tetra-n-butylammonium decatungstate (TBADT) and D2O as an inexpensive deuterium source. This deuteration can be adapted to PEG derivatives bearing various substituents ((hetero)aryl, benzoyl, alkyl, etc.). The deuteration efficiencies of the α-oxy C(sp3)-H bonds at the terminal positions of the PEGs were strongly influenced by the substituents. These reactivities were elucidated by density functional theory calculations of the reaction barriers towards the formation of radical intermediates, induced by the excited state of TBADT and the PEG substrate. In addition, the applicability of deuterated PEGs to internal standard experiments and Raman spectroscopy was demonstrated.

DOI： 10.1002/chem.202404204

PubMed

researchmap

Publisher：American Chemical Society (ACS)  

Fluorogenic probes for antigens are useful for various purposes, including medical diagnostics and imaging, but achieving a rapid, large fluorescence increase is difficult. Here, we report a new class of fluorogenic probes for antigens based on a conjugate of an antibody-mimetic DARPin bearing a site-specifically incorporated cysteine and silicon-pyronine (SiP), which reacts reversibly with thiols. By using a library-screening approach, we found that the absorbance and fluorescence of SiP conjugated to a DARPin are quenched by an addition reaction of the cysteine installed in the DARPin to SiP, and the equilibrium of this reaction is shifted to dissociation by antigen binding, leading to rapid, large increases of absorption and fluorescence. As a proof of concept of this chemical design principle, we constructed fluorogenic probes targeting GFP and EpCAM, which showed 25- and 12-fold fluorescence increases upon binding, respectively. The latter probe enabled wash-free cancer cell imaging with a low background.

DOI： 10.26434/chemrxiv-2024-3pplw

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Small extracellular vesicles (sEVs) are important intercellular information transmitters in various biological contexts, but their release processes remain poorly understood. Herein, we describe a high-throughput assay platform, CRISPR-assisted individually barcoded sEV-based release regulator (CIBER) screening, for identifying key players in sEV release. CIBER screening employs sEVs barcoded with CRISPR-gRNA through the interaction of gRNA and dead Cas9 fused with an sEV marker. Barcode quantification enables the estimation of the sEV amount released from each cell in a massively parallel manner. Barcoding sEVs with different sEV markers in a CRISPR pooled-screening format allows genome-wide exploration of sEV release regulators in a subpopulation-specific manner, successfully identifying previously unknown sEV release regulators and uncovering the exosomal/ectosomal nature of CD63+/CD9+ sEVs, respectively, as well as the synchronization of CD9+ sEV release with the cell cycle. CIBER should be a valuable tool for detailed studies on the biogenesis, release, and heterogeneity of sEVs.

DOI： 10.1038/s41467-024-53736-x

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

Stress granules (SGs) are cytoplasmic messenger ribonucleoprotein granules transiently formed in stressed mammalian cells. Although SG components have been well characterized, detailed insights into the molecular behavior inside SGs remain unresolved. We investigated nanoscale dynamics and localization of endogenous mRNAs in SGs combining single mRNA tracking and super-resolution localization microscopy. First, we developed a methodology for tracking single mRNAs within SGs, revealing that although mRNAs in SGs are mainly stationary (∼40%), they also move in a confined (∼25%) or freely diffusing (∼35%) manner. Second, the super-resolution localization microscopy showed that the mRNAs in SGs are heterogeneously distributed and partially form high-density clusters. Third, we simultaneously performed single mRNA tracking and super-resolution microscopy in SGs, demonstrating that single mRNA trajectories are mainly found around high-density clusters. Finally, a quantitative analysis of mRNA localization and dynamics during stress removal was conducted using live super-resolution imaging and single-molecule tracking. These results suggest that SGs have a highly organized structure that enables dynamic regulation of the mRNAs at the nanoscale, which is responsible for the ordered formation and the wide variety of functions of SGs.

DOI： 10.1093/nar/gkae588

researchmap

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.bmcl.2024.129757

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Senescent cells promote cancer development and progression through chronic inflammation caused by a senescence‐associated secretory phenotype (SASP). Although various senotherapeutic strategies targeting senescent cells have been developed for the prevention and treatment of cancers, technology for the in vivo detection and evaluation of senescent cell accumulation has not yet been established. Here, we identified activatable fluorescent probes targeting dipeptidylpeptidase‐4 (DPP4) as an effective probe for detecting senescent cells through an enzymatic activity‐based screening of fluorescent probes. We also determined that these probes were highly, selectively, and rapidly activated in senescent cells during live cell imaging. Furthermore, we successfully visualized senescent cells in the organs of mice using DPP4‐targeted probes. These results are expected to lead to the development of a diagnostic technology for noninvasively detecting senescent cells in vivo and could play a role in the application of DPP4 prodrugs for senotherapy.

DOI： 10.1111/cas.16229

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVES: Although the risk of complications due to postoperative pancreatic fistula (POPF) have been evaluated based on the amylase level in drained ascitic fluid, this method has much room for improvement regarding diagnostic accuracy and facility of the measurement. This study aimed to investigate the clinical value of measuring pancreatic chymotrypsin activity for rapid and accurate prediction of POPF after pancreaticoduodenectomy. METHODS: In 52 consecutive patients undergoing pancreaticoduodenectomy, the chymotrypsin activity in pancreatic juice was measured by calculating the increase in fluorescence intensity during the first 5 min after activation with an enzyme-activatable fluorophore. The predictive value for clinically relevant POPF (CR-POPF) was compared between this technique and the conventional method based on the amylase level. RESULTS: According to receiver operating characteristic analyses, pancreatic chymotrypsin activity on postoperative day (POD) 3 measured with a multiplate reader had the highest predictive value for CR-POPF (area under the curve [AUC], 0.752; P < 0.001), yielding 77.8 % sensitivity and 68.8 % specificity. The AUC and sensitivity/specificity of the amylase level in ascitic fluid on POD 3 were 0.695 (P = 0.053) and 77.8 %/41.2 %, respectively. Multivariable analysis identified high pancreatic chymotrypsin activity on POD 3 as an independent risk factor for CR-POPF. Measurement of pancreatic chymotrypsin activity with a prototype portable fluorescence photometer could significantly predict CR-POPF (AUC, 0.731; P = 0.010). CONCLUSION: Measurement of pancreatic chymotrypsin activity enabled accurate and rapid prediction of CR-POPF after pancreaticoduodenectomy. This can help surgeons to implement appropriate drain management at the patient's bedside without delay.

DOI： 10.1016/j.pan.2023.11.017

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Japanese Pharmacological Society  

DOI： 10.1254/fpj.23068

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Surgical resection is considered for most brain tumors to obtain tissue diagnosis and to eradicate or debulk the tumor. Glioma, the most common primary malignant brain tumor, generally has a poor prognosis despite the multidisciplinary treatments with radical resection and chemoradiotherapy. Surgical resection of glioma is often complicated by the obscure border between the tumor and the adjacent brain tissues and by the tumor's infiltration into the eloquent brain. 5-aminolevulinic acid is frequently used for tumor visualization, as it exhibits high fluorescence in high-grade glioma. Here, we provide an overview of the fluorescent probes currently used for brain tumors, as well as those under development for other cancers, including HMRG-based probes, 2MeSiR-based probes, and other aminopeptidase probes. We describe our recently developed HMRG-based probes in brain tumors, such as PR-HMRG, combined with the existing diagnosis approach. These probes are remarkably effective for cancer cell recognition. Thus, they can be potentially integrated into surgical treatment for intraoperative detection of cancers.

DOI： 10.3389/fsurg.2024.1298709

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/jacs.3c10086

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Although deuterium incorporation into pharmaceutical drugs is an attractive way to expand drug modalities, their physicochemical properties have not been sufficiently examined. This study focuses on examining the changes in physicochemical properties between flurbiprofen (FP) and flurbiprofen-d8 (FP-d8), which was successfully prepared by direct and multiple H/D exchange reactions at the eight aromatic C-H bonds of FP. Although the effect of deuterium incorporation was not observed between the crystal structures of FP and FP-d8, the melting point and heat of fusion of FP-d8 were lower than those of FP. Additionally, the solubility of FP-d8 increased by 2-fold compared to that of FP. Calculation of the interaction energy between FP/FP-d8 and water molecules using the multi-component density functional theory method resulted in increased solubility of FP-d8. These novel and valuable findings regarding the changes in physicochemical properties triggered by deuterium incorporation can contribute to the further development of deuterated drugs.

DOI： 10.1039/d3md00357d

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The proteasome plays a central role in intracellular protein degradation. Age-dependent decline in proteasome activity is associated with cellular senescence and organismal aging; however, the mechanism by which the proteasome plays a role in senescent cells remains elusive. Here, we show that nuclear foci that contain the proteasome and exhibit liquid-like properties are formed in senescent cells. The formation of senescence-associated nuclear proteasome foci (SANPs) is dependent on ubiquitination and RAD23B, similar to previously known nuclear proteasome foci, but also requires proteasome activity. RAD23B knockdown suppresses SANP formation and increases mitochondrial activity, leading to reactive oxygen species production without affecting other senescence traits such as cell-cycle arrest and cell morphology. These findings suggest that SANPs are an important feature of senescent cells and uncover a mechanism by which the proteasome plays a role in senescent cells.

DOI： 10.1016/j.celrep.2023.112880

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Super-resolution vibrational microscopy is promising to increase the degree of multiplexing of nanometer-scale biological imaging because of the narrower spectral linewidth of molecular vibration compared to fluorescence. However, current techniques of super-resolution vibrational microscopy suffer from various limitations including the need for cell fixation, high power loading, or complicated detection schemes. Here, we present reversible saturable optical Raman transitions (RESORT) microscopy, which overcomes these limitations by using photoswitchable stimulated Raman scattering (SRS). We first describe a bright photoswitchable Raman probe (DAE620) and validate its signal activation and depletion characteristics when exposed to low-power (microwatt level) continuous-wave laser light. By harnessing the SRS signal depletion of DAE620 through a donut-shaped beam, we demonstrate super-resolution vibrational imaging of mammalian cells with excellent chemical specificity and spatial resolution beyond the optical diffraction limit. Our results indicate RESORT microscopy to be an effective tool with high potential for multiplexed super-resolution imaging of live cells.

DOI： 10.1126/sciadv.ade9118

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Adult autologous human epidermal stem cells can be extensively expanded ex vivo for cell and gene therapy. Identifying the mechanisms involved in stem cell maintenance and defining culture conditions to maintain stemness is critical, because an inadequate environment can result in the rapid conversion of stem cells into progenitors/transient amplifying cells (clonal conversion), with deleterious consequences on the quality of the transplants and their ability to engraft. Here, we demonstrate that cultured human epidermal stem cells respond to a small drop in temperature through thermoTRP channels via mTOR signaling. Exposure of cells to rapamycin or a small drop in temperature induces the nuclear translocation of mTOR with an impact on gene expression. We also demonstrate by single-cell analysis that long-term inhibition of mTORC1 reduces clonal conversion and favors the maintenance of stemness. Taken together, our results demonstrate that human keratinocyte stem cells can adapt to environmental changes (e.g., small variations in temperature) through mTOR signaling and constant inhibition of mTORC1 favors stem cell maintenance, a finding of high importance for regenerative medicine applications.

DOI： 10.15252/embr.202255439

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Detecting multiple enzyme activities simultaneously with high spatial specificity is a promising strategy to investigate complex biological phenomena, and Raman imaging would be an excellent tool for this purpose due to its high multiplexing capabilities. We previously developed activatable Raman probes based on 9CN-pyronins, but specific visualization of cells with target enzyme activities proved difficult due to leakage of the hydrolysis products from the target cells after activation. Here, focusing on rhodol bearing a nitrile group at the position of 9 (9CN-rhodol), we established a novel mechanism for Raman signal activation based on a combination of aggregate formation (to increase local dye concentration) and the resonant Raman effect along with the bathochromic shift of the absorption, and utilized it to develop Raman probes. We selected the 9CN-rhodol derivative 9CN-JCR as offering a suitable combination of increased stimulated Raman scattering (SRS) signal intensity and high aggregate-forming ability, resulting in good retention in target cells after probe activation. By using isotope-edited 9CN-JCR-based probes, we could simultaneously detect β-galactosidase, γ-glutamyl transpeptidase, and dipeptidyl peptidase-4 activities in live cultured cells and distinguish cell regions expressing target enzyme activity in Drosophila wing disc and fat body ex vivo.

DOI： 10.1021/jacs.2c12381

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：S. Karger AG  

IntroductionComplete resection is the only possible treatment for cholangiocarcinoma in the extrahepatic biliary tree (eCCA), although current imaging modalities are limited in their ability to accurately diagnose longitudinal spread. We aimed to develop fluorescence imaging techniques for real-time identification of eCCA using an enzyme-activatable probe, which emits fluorescence immediately after activation by a cancer-specific enzyme.MethodsUsing lysates and small tissue fragments collected from surgically resected specimens, we selected the most specific probe for eCCA from among 800 enzyme-activatable probes. The selected probe was directly sprayed onto resected specimens and fluorescence images were acquired; these images were evaluated for diagnostic accuracy. We also comprehensively searched for enzymes that could activate the probe, then compared their expression levels in cancer and non-cancer tissues.ResultsAnalyses of 19 samples (four cancer lysates, seven non-cancer lysates, and eight bile samples) and 54 tissue fragments (13 cancer tissues and 41 non-cancer tissues) revealed that PM-2MeSiR was the most specific fluorophore for eCCA. Fluorescence images of seven patients were obtained; these images enabled rapid identification of cancerous regions, which closely matched histopathology findings in four patients. Puromycin-sensitive aminopeptidase was identified as the enzyme that might activate the probe, and its expression was upregulated in eCCA.Discussion/ConclusionFluorescence imaging with PM-2MeSiR, which may be activated by puromycin-sensitive aminopeptidase, yielded generally high accuracy. This technique may be useful for real-time identification of the spread of eCCA during surgery and endoscopic examinations.

DOI： 10.1159/000530645

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

In recent years, thoracoscopic and robotic surgical procedures have increasingly replaced median sternotomy for thymoma and thymic carcinoma. In cases of partial thymectomy, the prognosis is greatly improved by ensuring a sufficient margin from the tumor, and therefore intraoperative fluorescent imaging of the tumor is especially valuable in thoracoscopic and robotic surgery, where tactile information is not available. γ-Glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) has been applied for fluorescence imaging of some types of tumors in the resected tissues, and here we aimed to examine its validity for the imaging of thymoma and thymic carcinoma. 22 patients with thymoma or thymic carcinoma who underwent surgery between February 2013 and January 2021 were included in the study. Ex vivo imaging of specimens was performed, and the sensitivity and specificity of gGlu-HMRG were 77.3% and 100%, respectively. Immunohistochemistry (IHC) staining was performed to confirm expression of gGlu-HMRG's target enzyme, γ-glutamyltranspeptidase (GGT). IHC revealed high GGT expression in thymoma and thymic carcinoma in contrast to absent or low expression in normal thymic parenchyma and fat tissue. These results suggest the utility of gGlu-HMRG as a fluorescence probe for intraoperative visualization of thymomas and thymic carcinomas.

DOI： 10.1038/s41598-023-30753-2

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ajoc.202200710

researchmap

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ajoc.202200710

Publishing type：Research paper (scientific journal)  

DOI： 10.1002/asia.202201086

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ajoc.202200690

researchmap

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ajoc.202200690

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Rapid identification of lung-cancer micro-lesions is becoming increasingly important to improve the outcome of surgery by accurately defining the tumor/normal tissue margins and detecting tiny tumors, especially for patients with low lung function and early-stage cancer. The purpose of this study is to select and validate the best red fluorescent probe for rapid diagnosis of lung cancer by screening a library of 400 red fluorescent probes based on 2-methyl silicon rhodamine (2MeSiR) as the fluorescent scaffold, as well as to identify the target enzymes that activate the selected probe, and to confirm their expression in cancer cells. The selected probe, glutamine-alanine-2-methyl silicon rhodamine (QA-2MeSiR), showed 96.3% sensitivity and 85.2% specificity for visualization of lung cancer in surgically resected specimens within 10 min. In order to further reduce the background fluorescence while retaining the same side-chain structure, we modified QA-2MeSiR to obtain glutamine-alanine-2-methoxy silicon rhodamine (QA-2OMeSiR). This probe rapidly visualized even borderline lesions. Dipeptidyl peptidase 4 and puromycin-sensitive aminopeptidase were identified as enzymes mediating the cleavage and consequent fluorescence activation of QA-2OMeSiR, and it was confirmed that both enzymes are expressed in lung cancer. QA-2OMeSiR is a promising candidate for clinical application.

DOI： 10.1038/s41598-022-12665-9

researchmap

Other Link： https://www.nature.com/articles/s41598-022-12665-9

Language：English   Publishing type：Research paper (scientific journal)  

Acidification of intracellular vesicles, such as endosomes and lysosomes, is a key pathway for regulating the function of internal proteins. Most conventional methods of measuring pH are not satisfactory for quantifying the pH inside these vesicles. Here, we investigated the molecular requirements for a fluorescence probe to measure the intravesicular acidic pH in living cells by means of fluorescence lifetime imaging microscopy (FLIM). The developed probe, m-DiMeNAF488, exhibits a pH-dependent equilibrium between highly fluorescent and moderately fluorescent forms, which has distinct and detectable fluorescence lifetimes of 4.36 and 0.58 ns, respectively. The pKa(τ) value of m-DiMeNAF488 was determined to be 4.58, which would be favorable for evaluating the pH in the acidic vesicles. We were able to monitor the pH changes in phagosomes during phagocytosis by means of FLIM using m-DiMeNAF488. This probe is expected to be a useful tool for investigating acidic pH-regulated biological phenomena.

DOI： 10.1021/acs.analchem.2c01840

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Since gamma-glutamyl transpeptidase (GGT) is highly and locally expressed in human breast cancer, a GGT-enzymatically activatable fluorescent probe, gamma-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), has been developed to detect the human breast cancer area with high performance. In this study, GGT expression and the efficacy of gGlu-HMRG on visualization were investigated in canine mammary gland tumors (MGT). Seventeen non-fixed fresh-frozen MGT specimens and each peritumoral control tissue were utilized. The GGT mRNA levels were highly observed in the tumor specimens compared with the control. GGT immunostaining was mostly observed on the cell membrane and cytosol of the alveolar and duct mammary epithelium of MGT tissues. These signals were strongly positive in several cases while they were mild to not observed in other cases. When gGlu-HMRG solution was dropped to the non-fixed tissue pieces of MGT or control tissues, the fluorescence intensities (FIs) were measured using Maestro in-vivo imaging device. FIs in MGT tissues were significantly higher than each control tissue 20 min after treatment. Based on Youden index method said that the maximum sensitivity and specificity of FI was 82.4% and 82.4%. These findings suggest that GGT is highly expressed in several MGTs in dogs and gGlu-HMRG could visualize at least a part of MGT tissues in dogs. Nevertheless, it should be needed to assess the false-negative areas more carefully in canine than human cases.

DOI： 10.1292/jvms.22-0003

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Efficient methodology to develop tumor-imaging fluorescent probes based on screening with our newly constructed probe library for aminopeptidase/protease (380 probes) and clinical samples has been established.

DOI： 10.1039/d1sc06889j

researchmap

Publishing type：Research paper (scientific journal)   Publisher：The Company of Biologists  

<title>ABSTRACT</title>
Near-infrared fluorescent protein (iRFP) is a bright and stable fluorescent protein with near-infrared excitation and emission maxima. Unlike the other conventional fluorescent proteins, iRFP requires biliverdin (BV) as a chromophore. Here, we report that phycocyanobilin (PCB) functions as a brighter chromophore for iRFP than BV, and that biosynthesis of PCB allows live-cell imaging with iRFP in the fission yeast Schizosaccharomyces pombe. We initially found that fission yeast cells did not produce BV and therefore did not show any iRFP fluorescence. The brightness of iRFP–PCB was higher than that of iRFP–BV both in vitro and in fission yeast. We introduced SynPCB2.1, a PCB biosynthesis system, into fission yeast, resulting in the brightest iRFP fluorescence. To make iRFP readily available in fission yeast, we developed an endogenous gene tagging system with iRFP and all-in-one integration plasmids carrying the iRFP-fused marker proteins together with SynPCB2.1. These tools not only enable the easy use of multiplexed live-cell imaging in fission yeast with a broader color palette, but also open the door to new opportunities for near-infrared fluorescence imaging in a wider range of living organisms.


This article has an associated First Person interview with the first author of the paper.

DOI： 10.1242/jcs.259315

researchmap

Other Link： https://journals.biologists.com/jcs/article-pdf/doi/10.1242/jcs.259315/2125216/jcs259315.pdf

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nature Research  

DOI： 10.1038/s41598-021-97073-1

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nature Research  

DOI： 10.1038/s41598-021-88982-2

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

[Figure: see text].

DOI： 10.1126/sciadv.abg8585

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

DOI： 10.1016/j.bmc.2021.116281

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

PURPOSE: Five-aminolevulinic acid (5-ALA) is widely used as an intraoperative fluorescent probe for radical resection of high-grade glioma, and thus aids in extending progression-free survival of patients. However, there exist some cases where 5-ALA fails to fluoresce. In some other cases, it may undergo fluorescence quenching but cannot be orally readministered during surgery. This study aimed to develop a novel hydroxymethyl rhodamine green (HMRG)-based fluorescence labeling system that can be repeatedly administered as a topical spray during surgery for the detection of glioblastoma. EXPERIMENTAL DESIGN: We performed a three-stage probe screening using tumor lysates and fresh tumor tissues with our probe library consisting of a variety of HMRG probes with different dipeptides. We then performed proteome and transcript expression analyses to detect candidate enzymes responsible for cleaving the probe. Moreover, in vitro and ex vivo studies using U87 glioblastoma cell line were conducted to validate the findings. RESULTS: The probe screening identified proline-arginine-HMRG (PR-HMRG) as the optimal probe that distinguished tumors from peritumoral tissues. Proteome analysis identified calpain-1 (CAPN1) to be responsible for cleaving the probe. CAPN1 was highly expressed in tumor tissues which reacted to the PR-HMRG probe. Knockdown of this enzyme suppressed fluorescence intensity in U87 glioblastoma cells. In situ assay using a mouse U87 xenograft model demonstrated marked contrast of fluorescence with the probe between the tumor and peritumoral tissues. CONCLUSIONS: The novel fluorescent probe PR-HMRG is effective in detecting glioblastoma when applied topically. Further investigations are warranted to assess the efficacy and safety of its clinical use.

DOI： 10.1158/1078-0432.CCR-20-4518

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acs.analchem.0c04793

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the National Academy of Sciences  

<italic>Caenorhabditis elegans</italic> is used as a model system to understand the neural basis of behavior, but application of caged compounds to manipulate and monitor the neural activity is hampered by the innate photophobic response of the nematode to short-wavelength light or by the low temporal resolution of photocontrol. Here, we develop boron dipyrromethene (BODIPY)-derived caged compounds that release bioactive phenol derivatives upon illumination in the yellow wavelength range. We show that activation of the transient receptor potential vanilloid 1 (TRPV1) cation channel by spatially targeted optical uncaging of the TRPV1 agonist <italic>N</italic>-vanillylnonanamide at 580 nm modulates neural activity. Further, neuronal activation by illumination-induced uncaging enables optical control of the behavior of freely moving <italic>C. elegans</italic> without inducing a photophobic response and without crosstalk between uncaging and simultaneous fluorescence monitoring of neural activity.

DOI： 10.1073/pnas.2009634118

researchmap

Other Link： https://syndication.highwire.org/content/doi/10.1073/pnas.2009634118

Publishing type：Part of collection (book)   Publisher：Springer US  

DOI： 10.1007/978-1-0716-1258-3_17

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/D1CC01488A

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Introduction: Radical resection is the only curative treatment for pancreatic cancer, which is a life-threatening disease. However, it is often not easy to accurately identify the extent of the tumor before and during surgery. Here we describe the development of a novel method to detect pancreatic tumors using a tumor-specific enzyme-activatable fluorescence probe. Methods: Tumor and non-tumor lysate or small specimen collected from the resected specimen were selected to serve as the most appropriate fluorescence probe to distinguish cancer tissues from noncancerous tissues. The selected probe was sprayed onto the cut surface of the resected specimen of cancer tissue to acquire a fluorescence image. Next, we evaluated the ability of the probe to detect the tumor and calculated the tumor-to-background ratio (TBR) by comparing the fluorescence image with the pathological extent of the tumor. Finally, we searched for a tumor-specific enzyme that optimally activates the selected probe. Results: Using a library comprising 309 unique fluorescence probes, we selected GP-HMRG as the most appropriate activatable fluorescence probe. We obtained eight fluorescence images of resected specimens, among which four approximated the pathological findings of the tumor, which achieved the highest TBR. Finally, dipeptidyl-peptidase IV (DPP-IV) or a DPP-IV-like enzyme was identified as the target enzyme. Conclusion: This novel method may enable rapid and real-time visualization of pancreatic cancer through the enzymatic activities of cancer tissues.

DOI： 10.3389/fonc.2021.714527

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Accurate detection of breast tumors and discrimination of tumor from normal tissues during breast-conserving surgery are essential to reduce the risk of misdiagnosis or recurrence. However, existing probes show substantial background signals in normal breast tissues. In this study, we focus on glycosidase activities in breast tumors. We synthesized a series of 12 fluorescent probes and performed imaging-based evaluation on surgically resected human breast specimens. Among them, the α-mannosidase-reactive fluorescent probe HMRef-αMan detected breast cancer with 90% sensitivity and 100% specificity. We identified α-mannosidase 2C1 as the target enzyme and confirmed its overexpression in various breast tumors. We found that fibroadenoma, the most common benign breast lesion in young woman, tends to have higher α-mannosidase 2C1 activity than malignant cancer. Combined application of green-emitting HMRef-αMan and a red-emitting γ-glutamyltranspeptidase probe enabled efficient dual-color, dual-target optical discrimination of malignant and benign tumors.

DOI： 10.1021/acscentsci.0c01189

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Raman probes based on alkyne or nitrile tags hold promise for highly multiplexed imaging. However, sensing of enzyme activities with Raman probes is difficult because few mechanisms are available to modulate the vibrational response. Here we present a general strategy to prepare activatable Raman probes that show enhanced Raman signals due to electronic preresonance (EPR) upon reaction with enzymes under physiological conditions. We identified a xanthene derivative bearing a nitrile group at position 9 (9CN-JCP) as a suitable scaffold dye, and synthesized four types of activatable Raman probes, which are targeted to different enzymes (three aminopeptidases and a glycosidase) and tuned to different vibrational frequencies by isotope editing of the nitrile group. We validated the activation of the Raman signals of these probes by the target enzymes and succeeded in simultaneous imaging of the four enzyme activities in live cells. Different cell lines showed different patterns of these enzyme activities.

DOI： 10.1021/jacs.0c09200

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Bile leakage is the most common postoperative complication associated with hepatobiliary and pancreatic surgery. Until now, however, a rapid, accurate diagnostic method for monitoring intraoperative and postoperative bile leakage had not been established. METHOD: Bilirubin levels in drained abdominal fluids collected from 23 patients who had undergone hepatectomy (n = 22) or liver transplantation (n = 1) were measured using a microplate reader with excitation/emission wavelengths of 497/527 nm after applying 5 µM of UnaG to the samples. UnaG was also sprayed directly on hepatic raw surfaces in swine hepatectomy models to identify bile leaks by fluorescence imaging. RESULTS: The bilirubin levels measured by UnaG fluorescence imaging showed favorable correlations with the results of the conventional light-absorptiometric methods (indirect bilirubin: rs = 0.939, p < 0.001; direct bilirubin: rs = 0.929, p < 0.001). Approximate time required for bilirubin measurements with UnaG was 15 min, whereas it took about 40 min with the conventional method at a hospital laboratory. Following administration of UnaG on hepatic surfaces, the fluorescence imaging identified bile leaks not only on the resected specimens but also in the abdominal cavity of the swine hepatectomy models. CONCLUSION: Fluorescence imaging techniques using UnaG may enable real-time identification of bile leaks during hepatectomy and on-site rapid diagnosis of bile leaks after surgery.

DOI： 10.1007/s00268-020-05774-x

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVE: ɤ-glutamyltranspeptidase is an enzyme expressed in various malignancies including lung cancer. It rapidly activates non-fluorescent ɤ-glutamyl hydroxymethyl rhodamine green to highly fluorescent hydroxymethyl rhodamine green. The resultant tumor fluorescence is therefore an indicator of cellular ɤ-glutamyltranspeptidase activity. We have explored the use of ɤ-glutamyl hydroxymethyl rhodamine green as an intraoperative imaging tool for visualizing cancers. Herein, we evaluated the potential of the tumor fluorescence as a postoperative prognostic indicator. METHODS: We included patients with non-small cell lung cancer who had undergone radical resection from 2012 to 2014 in the study. We assessed the fluorescence intensity of the resected tumor and normal lung tissue by ex vivo imaging using ɤ-glutamyl hydroxymethyl rhodamine green. RESULTS: Sixty-seven patients were eligible for the study (adenocarcinomas, n = 44; squamous cell carcinoma, n = 14; other histologies, n = 8). The pathological stages were I, II, III, and IV in 39, 15, 12, and 1 patient, respectively. Based on the fluorescence of the tumor tissue, the patients were divided into high fluorescence (n = 33) and low fluorescence (n = 34) groups. The 5-year overall survival rate was significantly higher in the high fluorescence group (72.7%) compared to the low fluorescence group (47.1%, P = 0.025). Similarly, pathological stage I patients of the high fluorescence group had higher 5-year overall survival (85.7% vs. 44.4%, P = 0.009) and recurrence-free survival (76.2% vs. 44.4% P = 0.044) rates compared to those of the low fluorescence group. CONCLUSIONS: ɤ-glutamyl hydroxymethyl rhodamine green fluorescence is a good postoperative prognostic indicator in patients with non-small cell lung cancer.

DOI： 10.1007/s11748-020-01395-2

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Spontaneously blinking fluorophores are powerful tools for live-cell super-resolution imaging under physiological conditions. Here we show that quantum-chemical calculations can predict key parameters for fluorophore design. We applied this methodology to develop a spontaneously blinking fluorophore with yellow fluorescence for super-resolution imaging of microtubules in living cells.

DOI： 10.1039/d0cc05126h

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/anie.202013265

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Calpain activation induces retinal ganglion cell (RGC) death, while calpain inhibition suppresses RGC death, in animal studies. However, the role of calpain in human retinal disease is unclear. This study investigated a new strategy to study the role of calpain based on real-time imaging. We synthesized a novel fluorescent probe for calpain, acetyl-l-leucyl-l-methionine-hydroxymethyl rhodamine green (Ac-LM-HMRG) and used it for real-time imaging of calpain activation. The toxicity of Ac-LM-HMRG was evaluated with a lactate dehydrogenase cytotoxicity assay, retinal sections, and electroretinograms. Here, we performed real-time imaging of calpain activation in a rat model. First, we administered N-methyl-d-aspartate (NMDA) to induce retinal injury. Twenty minutes later, we administered an intravitreal injection of Ac-LM-HMRG. Real-time imaging was then completed with a noninvasive confocal scanning laser ophthalmoscope. The inhibitory effect of SNJ-1945 against calpain activation was also examined with the same real-time imaging method. Ac-LM-HMRG had no toxic effects. The number of Ac-LM-HMRG-positive cells in real-time imaging significantly increased after NMDA injury, and SNJ-1945 significantly lowered the number of Ac-LM-HMRG-positive cells. Real-time imaging with Ac-LM-HMRG was able to quickly quantify the NMDA-induced activation of calpain and the inhibitory effect of SNJ-1945. This technique, used as a companion diagnostic system, may aid research into the development of new neuroprotective therapies.

DOI： 10.1021/acs.bioconjchem.0c00435

PubMed

researchmap

Language：Japanese   Publisher：(NPO)日本レーザー医学会  

researchmap

Publishing type：Research paper (scientific journal)   Publisher：American Society of Plant Biologists (ASPB)  

DOI： 10.1105/tpc.20.00439

researchmap

Language：Japanese   Publisher：(一社)日本呼吸器外科学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/s42004-020-0326-x

Web of Science

researchmap

Publisher：American Chemical Society (ACS)  

Actin
is a ubiquitous cytoskeletal protein, forming a dynamic network that generates
mechanical forces in the cell. Here, in order to dissect the complex mechanisms
of actin-related cellular functions, we introduce two powerful tools based on a
new class of actin-binding small molecule: one enables visualization of the
actin cytoskeleton, including super-resolution imaging, and the other enables
highly specific green-light-controlled fragmentation of actin filaments,
affording unprecedented control of the actin cytoskeleton and its force network
in living cells.

DOI： 10.26434/chemrxiv.12272024.v1

researchmap

Language：English  

Single-molecule localization microscopy (SMLM) allows the reconstruction of super-resolution images, but generally requires prior intense laser irradiation and in some cases additives to induce blinking of conventional fluorophores. We previously introduced a spontaneously blinking rhodamine fluorophore based on an intramolecular spirocyclization reaction for live-cell SMLM under physiological conditions. Here, we report a novel principle of spontaneous blinking in living cells, which utilizes reversible ground-state nucleophilic attack of intracellular glutathione (GSH) upon a xanthene fluorophore. Structural optimization afforded two pyronine fluorophores with different colors, both of which exhibit equilibrium (between the fluorescent dissociated form and the non-fluorescent GSH adduct form) and blinking kinetics that enable SMLM of microtubules in living cells. Furthermore, by using spontaneously blinking fluorophores working in the near-infrared (NIR) and green ranges, we succeeded in dual-color live-cell SMLM without the need for optimization of the imaging medium.

DOI： 10.1021/jacs.0c00451

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

DOI： 10.1016/j.bmcl.2019.126860

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/s12885-020-6537-9

Web of Science

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/D0CC00559B

researchmap

Language：English   Publishing type：Part of collection (book)   Publisher：Humana Press Inc.  

DOI： 10.1007/978-1-0716-0532-5_10

Scopus

researchmap

Language：Japanese   Publisher：(NPO)日本レーザー医学会  

researchmap

Language：Japanese   Publisher：(公財)日本眼科学会  

researchmap

J-GLOBAL

researchmap