Indoles Oxidative Ring-Opening/Cyclization Cascade with the 1,2-Diaminoarenes: Direct Synthesis of 2-Aryl-3-(2-aminoaryl)quinoxalines.

A mild oxidative sequential tandem reaction was developed to rapidly generate 2-aryl-3-(2-aminoaryl) quinoxalines. This method exploited 2-substituted indoles as substrate to form quinoxalines in a one-pot reaction. The key to this tandem reaction was the formation of 3-iodoindoles, which underwent Kornblum-type oxidation with DMSO to generate active imine 2-substitued 3H-indol-3-ones. The active imines were captured in situ by 1,2-diaminobenzenes to construct diverse quinoxalines. The transformation can be accomplished at room temperature with excellent functional group tolerance.

Discovery of highly potent SARS-CoV-2 Mpro inhibitors based on benzoisothiazolone scaffold.

The COVID-19 pandemic has drastically impacted global economies and public health. Although vaccine development has been successful, it was not sufficient against more infectious mutant strains including the Delta variant indicating a need for alternative treatment strategies such as small molecular compound development. In this work, a series of SARS-CoV-2 main protease (Mpro) inhibitors were designed and tested based on the active compound from high-throughput diverse compound library screens. The most efficacious compound (16b-3) displayed potent SARS-CoV-2 Mpro inhibition with an IC50 value of 116 nM and selectivity against SARS-CoV-2 Mpro when compared to PLpro and RdRp. This new class of compounds could be used as potential leads for further optimization in anti COVID-19 drug discovery.

DGAT1 inhibitors protect pancreatic ß-cells from palmitic acid-induced apoptosis.

Previous studies demonstrated that prolonged exposure to elevated levels of free fatty acids (FFA), especially saturated fatty acids, could lead to pancreatic ß-cell apoptosis, which plays an important role in the progression of type 2 diabetes (T2D). Diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the final step of triglyceride (TG) synthesis, has been reported as a novel target for the treatment of multiple metabolic diseases. In this study we evaluated the potential beneficial effects of DGAT1 inhibitors on pancreatic ß-cells, and further verified their antidiabetic effects in db/db mice. We showed that DGAT1 inhibitors (4a and LCQ908) at the concentration of 1 µM significantly ameliorated palmitic acid (PA)-induced apoptosis in MIN6 pancreatic ß-cells and primary cultured mouse islets; oral administration of a DGAT1 inhibitor (4a) (100 mg/kg) for 4 weeks significantly reduced the apoptosis of pancreatic islets in db/db mice. Meanwhile, 4a administration significantly decreased fasting blood glucose and TG levels, and improved glucose tolerance and insulin tolerance in db/db mice. Furthermore, we revealed that pretreatment with 4a (1 µM) significantly alleviated PA-induced intracellular lipid accumulation, endoplasmic reticulum (ER) stress, and proinflammatory responses in MIN6 cells, which might contribute to the protective effects of DGAT1 inhibitors on pancreatic ß-cells. These findings provided a better understanding of the antidiabetic effects of DGAT1 inhibitors.

A Novel 2-Phenylamino-Quinazoline-Based Compound Expands the Neural Stem Cell Pool and Promotes the Hippocampal Neurogenesis and the Cognitive Ability of Adult Mice.

The adult neurogenesis occurs throughout the life of the mammalian hippocampus and is found to be essential for learning and memory. Identifying new ways to manipulate the number of neural stem cells (NSCs) and enhance endogenous neurogenesis in adults is very important. Here we found that a novel compound, N2-(4-isopropylphenyl)-5-(3-methoxyphenoxy)quinazoline-2,4-diamine (code-named Yhhu-3792), enhanced the self-renewal capability of NSCs in vitro and in vivo. In vitro, Yhhu-3792 increased the ratio of 5-Bromo-2-deoxyuridine+ /4'-6-diamidino-2-phenylindole+ embryonic NSCs and accelerated the growth of neurospheres significantly. We demonstrated that Yhhu-3792 activated Notch signaling pathway and promoted the expression of Notch target genes, Hes3 and Hes5. And the Notch signaling inhibitor DAPT could inhibit its function. Thus, we concluded Yhhu-3792 increased the number of embryonic NSCs via activating the Notch signaling pathway. We measured the effect of Yhhu-3792 on epidermal growth factor receptor signaling, which demonstrated Yhhu-3792 act via a different mechanism with the quinazoline parent chemical group. In the eight-week-old male C57BL/6 mice, chronic Yhhu-3792 administration expanded the NSCs pool and promoted endogenous neurogenesis in the hippocampal dentate gyrus (DG). It also increased the spatial and episodic memory abilities of mice, when evaluated with the Morris water maze and Fear conditioning tests. In conclusion, Yhhu-3792 could be a novel drug candidate to promote the self-renew of NSCs and adult neurogenesis. And it may have therapeutic potential in the impairment of learning and memory associated DG dysfunction. Stem Cells 2018;36:1273-1285.

Base-Promoted Cascade Reactions of 3-(1-Alkynyl)chromones with Pyridinium Ylides to Chromeno[2,3- d]azepine Derivatives.

A base-promoted cascade reaction of 3-(1-alkynyl)chromones with pyridinium ylides has been developed to afford a novel chromeno[2,3- d]azepine scaffold in an efficient and economic manner. This tandem process involves multiple reactions including a Michael addition/deprotonation/alkyne-allene isomerization/cyclization and the subsequent 1,2-addition under mild conditions without a transition metal catalyst.

Targeting Gpr52 lowers mutant HTT levels and rescues Huntington's disease-associated phenotypes.

See Huang and Gitler (doi:10.1093/brain/awy112) for a scientific commentary on this article.Lowering the levels of disease-causing proteins is an attractive treatment strategy for neurodegenerative disorders, among which Huntington's disease is an appealing disease for testing this strategy because of its monogenetic nature. Huntington's disease is mainly caused by cytotoxicity of the mutant HTT protein with an expanded polyglutamine repeat tract. Lowering the soluble mutant HTT may reduce its downstream toxicity and provide potential treatment for Huntington's disease. This is hard to achieve by small-molecule compound drugs because of a lack of effective targets. Here we demonstrate Gpr52, an orphan G protein-coupled receptor, as a potential Huntington's disease drug target. Knocking-out Gpr52 significantly reduces mutant HTT levels in the striatum and rescues Huntington's disease-associated behavioural phenotypes in a knock-in Huntington's disease mouse model expressing endogenous mutant Htt. Importantly, a novel Gpr52 antagonist E7 reduces mutant HTT levels and rescues Huntington's disease-associated phenotypes in cellular and mouse models. Our study provides an entry point for Huntington's disease drug discovery by targeting Gpr52.

Fluorescent Imaging of ß-Amyloid Using BODIPY Based Near-Infrared Off-On Fluorescent Probe.

Fluorescent imaging of ß-amyloid (Aß) is one of the most promising methods for Alzheimer's disease diagnosis. Several fluorescent probes have been reported to detect Aß both in vitro and in vivo. However, highly sensitive and highly selective probes with low background signals are still greatly needed. Herein, we rationally designed and synthesized a PIET quenched near-infrared probe QAD-1 to detect Aß. This probe contains BODIPY as fluorophore and tetrahydroquinoxaline as the quenching group. QAD-1 exhibited significant fluorescent switch-on after binding to soluble and insoluble Aß species, and the probe had the benefit of low background signal to stain Aß plaques without the need of wash-out procedures in vitro, which was specially found by the fluorescence off-on probe. QAD-1 could identify the overproduced Aß in transgenic (APPSWE/PSEN 1dE9) AD mice as early as 6 months old in vivo, which indicated that QAD-1 may be a potential probe for monitoring Aß species at an early stage of AD.

[Quality control of Dandeng Tongnao Ruanjiaonang based on UPLC fingerprint combined with chemical pattern recognition].

To establish the ultra performance liquid chromatography (UPLC) fingerprint of Dandeng Tongnao Ruanjiaonang and conduct a systemic, comprehensive quality evaluation of the drug by combining with a chemical pattern recognition method. In this study, Waters UPLC ultra-high performance liquid chromatography instrument and ACQUITY UPLCHSS T3 chromatographic colum n were employed to perform the separation with acetonitrile-0.1% formic acid aqueous solution as the mobile phase for gradient elution; and the detection wavelength was set at 256 nm to establish the UPLC fingerprint of 10 batches of Dandeng Tongnao Ruanjiaonang. Then, the further quality assessment of the drug was carried out by similarity evaluation, Cluster Analysis(CA), Principal Component Analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Finally, 77 peaks were recognised as common peaks in the fingerprint, and 15 peaks of them were identified using standard references. The similarity value of these 10 batches of drugs was all above 0.960, indicating a relatively stable quality. But minor differences were still discovered between the batches of the drug by CA and PCA. Finally, 6 common peaks were recognised as the quality makers using OPLS-DA method. The analysis method established in this study was scientific, accurate, reliable and simple; fingerprint combined with chemical pattern recognition technique can be used to systematically and comprehensively evaluate the drug quality of Dandeng Tongnao Ruanjiaonang; what's more, it could also provide a reference for the quality control of traditional Chinese medicine and its preparations at the same time.

Discovery of a low-systemic-exposure DGAT-1 inhibitor with a picolinoylpyrrolidine-2-carboxylic acid moiety.

A series of diacylglycerol O-acyltransferase 1 (DGAT-1) inhibitors with a picolinoylpyrrolidine-2-carboxylic acid moiety were designed and synthesized. Of these compounds, compound 22 exhibited excellent DGAT-1-inhibitory activity (hDGAT-1 enzyme assay, 50% inhibitory concentration [IC50]=3.5±0.9nM) and effectively reduced the intracellular triglyceride contents in 3T3-L1, HepG2 and Caco-2 cells. A preliminary study of the plasma and tissue distributions of compound 22 in mice revealed low plasma exposure and high concentrations in different segments of the intestine and liver, which may facilitate targeting DGAT-1. Furthermore, in an acute lipid challenge test, compound 22 showed a dose-dependent inhibitory effect on high-serum triglycerides in C57/KSJ mice induced by olive oil (1, 3, and 10mg/kg, i.g.).

Y-632 inhibits heat shock protein 90 (Hsp90) function by disrupting the interaction between Hsp90 and Hsp70/Hsp90 organizing protein, and exerts antitumor activity in vitro and in vivo.

Heat shock protein 90 (Hsp90) stabilizes a variety of proteins required for cancer cell survival and has been identified as a promising drug target for cancer treatment. To date, several Hsp90 inhibitors have entered into clinical trials, but none has been approved for cancer therapy yet. Thus, exploring new Hsp90 inhibitors with novel mechanisms of action is urgent. In the present study, we show that Y-632, a novel pyrimidine derivative, inhibited Hsp90 in a different way from the conventional Hsp90 inhibitor geldanamycin. Y-632 induced degradation of diverse Hsp90 client proteins through the ubiquitin-proteasome pathway, as geldanamycin did; however, it neither directly bound to Hsp90 nor inhibited Hsp90 ATPase activity. Y-632 inhibited Hsp90 function mainly through inducing intracellular thiol oxidation, which led to disruption of the Hsp90-Hsp70/Hsp90 organizing protein complex and further induced cell adhesion inhibition, G0 /G1 cell cycle arrest, and apoptosis. Moreover, Y-632 efficiently overcame imatinib resistance mediated by Bcr-Abl point mutations both in vitro and in vivo. We believe that Y-632, acting as a novel small-molecule inhibitor of the Hsp90-Hsp70/Hsp90 organizing protein complex, has great potential to be a promising Hsp90 inhibitor for cancer therapy, such as for imatinib-resistant leukemia.

Discovery of 4-chloro-3-(5-(pyridin-3-yl)-1,2,4-oxadiazole-3-yl)benzamides as novel RET kinase inhibitors.

A series of novel 4-chloro-benzamides derivatives containing substituted five-membered heteroaryl ring were designed, synthesized and evaluated as RET kinase inhibitors for cancer therapy. Most of compounds exhibited moderate to high potency in ELISA-based kinase assay. In particular, compound I-8 containing 1,2,4-oxadiazole strongly inhibited RET kinase activity both in molecular and cellular level. In turn, I-8 inhibited cell proliferation driven by RET wildtype and gatekeeper mutation. The results implied that 4-chloro-3-(5-(pyridin-3-yl)-1,2,4-oxadiazole-3-yl)benzamides are promising lead compounds as novel RET kinase inhibitor for further investigation.

Advances in development of fluorescent probes for detecting amyloid-ß aggregates.

With accumulating evidence suggesting that amyloid-ß (Aß) deposition is a good diagnostic biomarker for Alzheimer's disease (AD), the discovery of active Aß probes has become an active area of research. Among the existing imaging methods, optical imaging targeting Aß aggregates (fibrils or oligomers), especially using near-infrared (NIR) fluorescent probes, is increasingly recognized as a promising approach for the early diagnosis of AD due to its real time detection, low cost, lack of radioactive exposure and high-resolution. In the past decade, a variety of fluorescent probes have been developed and tested for efficiency in vitro, and several probes have shown efficacy in AD transgenic mice. This review classifies these representative probes based on their chemical structures and functional modes (dominant solvent-dependent mode and a novel solvent-independent mode). Moreover, the pharmaceutical characteristics of these representative probes are summarized and discussed. This review provides important perspectives for the future development of novel NIR Aß diagnostic probes.

Novel CHOP activator LGH00168 induces necroptosis in A549 human lung cancer cells via ROS-mediated ER stress and NF-κB inhibition.

AIM: C/EBP homologous protein (CHOP) is a transcription factor that is activated at multiple levels during ER stress and plays an important role in ER stress-induced apoptosis. In this study we identified a novel CHOP activator, and further investigated its potential to be a therapeutic agent for human lung cancer. METHODS: HEK293-CHOP-luc reporter cells were used in high-throughput screening (HTS) to identify CHOP activators. The cytotoxicity against cancer cells in vitro was measured with MTT assay. The anticancer effects were further examined in A549 human non-small cell lung cancer xenograft mice. The mechanisms underlying CHOP activation were analyzed using luciferase assays, and the anticancer mechanisms were elucidated in A549 cells. RESULTS: From chemical libraries of 50 000 compounds, LGH00168 was identified as a CHOP activator, which showed cytotoxic activities against a panel of 9 cancer cell lines with an average IC50 value of 3.26 µmol/L. Moreover, administration of LGH00168 significantly suppressed tumor growth in A549 xenograft bearing mice. LGH00168 activated CHOP promoter via AARE1 and AP1 elements, increased DR5 expression, decreased Bcl-2 expression, and inhibited the NF-κB pathway. Treatment of A549 cells with LGH00168 (10 µmol/L) did not induce apoptosis, but lead to RIP1-dependent necroptosis, accompanied by cell swelling, plasma membrane rupture, lysosomal membrane permeabilization, MMP collapse and caspase 8 inhibition. Furthermore, LGH00168 (10 and 20 µmol/L) dose-dependently induced mito-ROS production in A549 cells, which was reversed by the ROS scavenger N-acetyl-L-cysteine (NAC, 10 mmol/L). Moreover, NAC significantly diminished LGH00168-induced CHOP activation, NF-κB inhibition and necroptosis in A549 cells. CONCLUSION: LGH00168 is a CHOP activator that inhibits A549 cell growth in vitro and lung tumor growth in vivo.

Visualizing peroxynitrite fluxes in endothelial cells reveals the dynamic progression of brain vascular injury.

Accumulating evidence suggests that formation of peroxynitrite (ONOO(-)) in the cerebral vasculature contributes to the progression of ischemic damage, while the underlying molecular mechanisms remain elusive. To fully understand ONOO(-) biology, efficient tools that can realize the real-time tracing of endogenous ONOO(-) fluxes are indispensable. While a few ONOO(-) fluorescent probes have been reported, direct visualization of ONOO(-) fluxes in the cerebral vasculature of live mice remains a challenge. Herein, we present a fluorescent switch-on probe (NP3) for ONOO(-) imaging. NP3 exhibits good specificity, fast response, and high sensitivity toward ONOO(-) both in vitro and in vivo. Moreover, NP3 is two-photon excitable and readily blood-brain barrier penetrable. These desired photophysical and pharmacokinetic properties endow NP3 with the capability to monitor brain vascular ONOO(-) generation after injury with excellent temporal and spatial resolution. As a proof of concept, NP3 has enabled the direct visualization of neurovascular ONOO(-) formation in ischemia progression in live mouse brain by use of two-photon laser scanning microscopy. Due to these favorable properties, NP3 holds great promise for visualizing endogenous peroxynitrite fluxes in a variety of pathophysiological progressions in vitro and in vivo.

A novel pyridazinone derivative inhibits hepatitis B virus replication by inducing genome-free capsid formation.

Here we first identified a novel pyridazinone derivative, compound 3711, as a nonnucleosidic hepatitis B virus (HBV) inhibitor in a cell model system. 3711 decreased extracellular HBV DNA levels by 50% (50% inhibitory concentration [IC50]) at 1.5 ± 0.2 µM and intracellular DNA levels at 1.9 ± 0.1 µM, which demonstrated antiviral activity at levels far below those associated with toxicity. Both the 3TC/ETV dually resistant L180M/M204I mutant and the adefovir (ADV)-resistant A181T/N236T mutant were as susceptible to 3711 as wild-type HBV. 3711 treatment induced the formation of genome-free capsids, a portion of which migrated faster on 1.8% native agarose gel. The induced genome-free capsids sedimented more slowly in isopycnic CsCl gradient centrifugation without significant morphological changes. 3711 treatment decreased levels of HBV DNA contained in both secreted enveloped virion and naked virus particles in supernatant. 3711 could interfere with capsid formation of the core protein (Cp) assembly domain. A Cp V124W mutant, which strengthens capsid interdimer interactions, recapitulated the effect of 3711 on capsid assembly. Pyridazinone derivative 3711, a novel chemical entity and HBV inhibitor, may provide a new opportunity to combat chronic HBV infection.

Yhhu4488, a novel GPR40 agonist, promotes GLP-1 secretion and exerts anti-diabetic effect in rodent models.

G protein-coupled receptor 40 (GPR40) is predominantly expressed in pancreatic ß-cells and activated by long-chain fatty acids. GPR40 has drawn considerable interest as a potential therapeutic target for type 2 diabetes mellitus (T2DM) due to its important role in enhancing glucose-stimulated insulin secretion (GSIS). Encouragingly, GPR40 is also proven to be highly expressed in glucagon-like peptide-1 (GLP-1)-producing enteroendocrine cells afterwards, which opens a potential role of GPR40 in enhancing GLP-1 secretion to exert additional anti-diabetic efficacy. In the present study, we discovered a novel GPR40 agonist, yhhu4488, which is structurally different from other reported GPR40 agonists. Yhhu4488 showed potent agonist activity with EC50 of 49.96 nM, 70.83 nM and 58.68 nM in HEK293 cells stably expressing human, rat and mouse GPR40, respectively. Yhhu4488 stimulated GLP-1 secretion from fetal rat intestinal cells (FRIC) via triggering endogenous calcium store mobilization and extracellular calcium influx. The effect of yhhu4488 on GLP-1 secretion was further confirmed in type 2 diabetic db/db mice. Yhhu4488 exhibited satisfactory potency in in vivo studies. Single administration of yhhu4488 improved glucose tolerance in SD rats. Chronic administration of yhhu4488 effectively decreased fasting blood glucose level, improved ß-cell function and lipid homeostasis in type 2 diabetic ob/ob mice. Taken together, yhhu4488 is a novel GPR40 agonist that enhances GLP-1 secretion, improves metabolic control and ß-cell function, suggesting its promising potential for the treatment of type 2 diabetes.

Yhhu981, a novel compound, stimulates fatty acid oxidation via the activation of AMPK and ameliorates lipid metabolism disorder in ob/ob mice.

AIM: Defects in fatty acid metabolism contribute to the pathogenesis of insulin resistance and obesity. In this study, we investigated the effects of a novel compound yhhu981 on fatty acid metabolism in vitro and in vivo. METHODS: The capacity to stimulate fatty acid oxidation was assessed in C2C12 myotubes. The fatty acid synthesis was studied in HepG2 cells using isotope tracing. The phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) was examined with Western blot analysis. For in vivo experiments, ob/ob mice were orally treated with yhhu981 acutely (300 mg/kg) or chronically (150 or 300 mg·kg(-1)·d(-1) for 22 d). On the last day of treatment, serum and tissue samples were collected for analysis. RESULTS: Yhhu981 (12.5-25 µmol/L) significantly increased fatty acid oxidation and the expression of related genes (Sirt1, Pgc1α and Mcad) in C2C12 myotubes, and inhibited fatty acid synthesis in HepG2 cells. Furthermore, yhhu981 dose-dependently increased the phosphorylation of AMPK and ACC in both C2C12 myotubes and HepG2 cells. Compound C, an AMPK inhibitor, blocked fatty acid oxidation in yhhu981-treated C2C12 myotubes and fatty acid synthesis decrease in yhhu981-treated HepG2 cells. Acute administration of yhhu981 decreased the respiratory exchange ratio in ob/ob mice, whereas chronic treatment with yhhu981 ameliorated the lipid abnormalities and ectopic lipid deposition in skeletal muscle and liver of ob/ob mice. CONCLUSION: Yhhu981 is a potent compound that stimulates fatty acid oxidation, and exerts pleiotropic effects on lipid metabolism by activating AMPK.

Yhhu3813 is a novel selective inhibitor of c-Met kinase that inhibits c-Met-dependent neoplastic phenotypes of human cancer cells.

AIM: c-Met kinase deregulation is strongly associated with the formation, progression and dissemination of human cancers. In this study we identified Yhhu3813 as a small-molecule inhibitor of c-Met kinase and characterized its antitumor properties both in vitro and in vivo. METHODS: The activities of different kinases were measured using ELISA assays and signaling proteins in the cells were detected with Western blotting. Cell proliferation was assessed using SRB or MTT assay in twenty human cell lines and cell cycle distribution was determined with flow cytometry. Transwell-based assay was used to evaluate cell migration and invasion. Cell invasive growth was detected by a morphogenesis assay. c-Met overactivated human NSCLC cell line EBC-1 xenografts were used to evaluate the in vivo anti-tumor efficacy. RESULTS: Yhhu3813 potently inhibited c-Met kinase activity in vitro with an IC50 value of 2.4±0.3 nmol/L, >400-fold higher than that for a panel of 15 different tyrosine kinases, suggesting a high selectivity of Yhhu3813. The compound (20, 100 and 500 nmol/L) dose-dependently inhibited the phosphorylation of c-Met and its key downstream Akt and Erk signal cascades in multiple c-Met aberrant human cancer cell lines, regardless of the mechanistic complexity in c-Met activation across different cellular contexts. In 20 human cancer cell lines harboring different backgrounds of c-Met expression/activation, Yhhu3813 potently inhibited c-Met-driven cell proliferation via arresting cells at G1/S phase. Furthermore, Yhhu3813 substantially impaired c-Met-mediated cell migration, invasion, scattering, and invasive growth. Oral administration of EBC-1 xenograft mice with Yhhu3813 (50 or 100 mg·kg(-1)·d(-1), qd, for 2 weeks) dose-dependently suppressed the tumor growth, which was correlated with a reduction in the intratumoral proliferation index and c-Met signaling. CONCLUSION: Yhhu3813 is a potent selective inhibitor of c-Met that inhibits c-Met-dependent neoplastic phenotypes of human cancer cells in vitro and in vivo.

Discovering novel anti-HCV compounds with inhibitory activities toward HCV NS3/4A protease.

AIM: To discover novel hepatitis C virus (HCV) inhibitors and elucidate the mechanism of action of the active compounds. METHODS: HCV subgenomic replicon-based luciferase reporter cell line was used to screen 1200 synthetic compounds with novel structures. Huh7.5.1 cell line stably transfected with HCV NS3/4A protease reporter was established to investigate the anti-HCV mechanism of the active compounds. The active compounds were further examined in an in vitro HCV infection assay to confirm their anti-HCV activity. RESULTS: After two-round screening in the anti-HCV replicon assay, some 2,4-diaminoquinazoline derivatives and carboxamide analogues were found to possess anti-HCV replicon activities (the IC50 values were less than 5 µmol/L). Among them, two representative compounds HZ-1157 and LZ-110618-6 inhibited HCV NS3/4A protease with IC50 values of 1.0 and 0.68 µmol/L, respectively. Furthermore, HZ-1157 and LZ-110618-6 inhibited HCV infection in vitro with IC50 values of 0.82 and 0.11 µmol/L, respectively. CONCLUSION: Some 2,4-diaminoquinazoline derivatives and carboxamide analogues have been identified as novel anti-HCV compounds.

A novel BODIPY-based theranostic agent for in vivo fluorescence imaging of cerebral Aß and ameliorating Aß-associated disorders in Alzheimer's disease transgenic mice.

ß-Amyloid (Aß) aggregation is increasingly recognized as both a biomarker and an inducer of the progression of Alzheimer's disease (AD). Here, we describe a novel fluorescent probe P14, developed based on the BODIPY structure, capable of simultaneous visualization and inhibition of Aß aggregation in vivo. P14 shows high binding affinity to Aß aggregates and selectively labels Aß plaques in the brain slices of APP/PS1 mice. Moreover, P14 is able to visualize overloaded Aß in both APP/PS1 and 5 × FAD transgenic mice in vivo. From the aspect of potential therapeutic effects, P14 administration inhibits Aß aggregation and alleviates Aß-induced neuronal damage in vitro, as well as reduces central Aß deposition and ameliorates cognitive impairment in APP/PS1 transgenic mice in vivo. Finally, P14 is applied to monitor the progression of Aß aggregation in the brain of 5 × FAD transgenic mice and the intervention effect itself by fluorescence imaging. In summary, the discovery of this fluorescent agent might provide important clues for the future development of theranostic drug candidates targeting Aß aggregation in AD.