Indole-Based Long-Wavelength Fluorescent Probes for Bioimaging of S-Nitrosylation in Mitochondria

S-Nitrosylation has been found to play an important role in regulating mitochondrial function. However, probes for detection of protein S-nitrosylation in mitochondria remain unexplored. Herein, a novel 4-(pyridin-4-yl)vinyl-substituted indole was designed, exhibiting a long-wavelength emission and a high fluorescent quantum yield. Functionalization of the 7-position of the indole ring with an arylphosphine ester resulted with probes with efficient mitochondria-targeting ability. Furthermore, the indole-arylphosphine displayed a significant fluorescence enhancement upon exposure to S-nitrosoglutathione (GSNO) at low micromolar concentrations in A431 cells. Taken together, this study provides a new indole-based fluorescent probe with a unique long-wavelength emission for direct detection of S-nitrosylation in mitochondria, which may represent a powerful tool for understanding the critical roles of S-nitrosylation within mitochondria of living organisms.     

基于粘度响应的线粒体靶向铱(Ⅲ)配合物用于肿瘤的光动力治疗

合成了2种含有转动基团的铱配合物Ir1和Ir2。研究发现Ir1和Ir2对粘度具有灵敏的荧光响应,在高粘度环境下,其荧光强度分别提高了35.7倍和1311.6倍。细胞摄取和共定位实验表明该探针能够轻易地穿过细胞膜并靶向聚集于线粒体中,对线粒体内粘度进行荧光成像检测。另外,通过EPR电子顺磁共振仪检测到Ir1和Ir2在光照下能够产生大量的单线态氧;同时发现配合物在肿瘤细胞中也能够产生高毒性的单线态氧,使Ir1和Ir2对A549细胞和Hep-G2细胞表现出很强的光毒性从而导致细胞死亡。     

Rational Design of Self-Assembled Mitochondria-Targeting Lytic Peptide Conjugates with Enhanced Tumor Selectivity

Membrane lytic peptides (MLP) are widely explored as cellular delivery vehicles or antitumor/antibacterial agents. However, the poor selectivity between cancer and normal cells slims their prospects as potential anti-tumor drugs. Herein, we have developed a rationally designed self-assembly strategy to enhance tumor selectivity of MLP-based conjugates, incorporating a hydrophobic triphenylphosphonium (TPP) group for mitochondria targeting, and a hydrophilic arginine-glycine-aspartic acid (RGD) sequence targeting integrins. The self-assembly nanoparticles can enhance the stability of the peptides in vitro plasma and be endocytosed selectively into the cancer cells. The histidine-rich lytic peptide component assists the disruption of endosomal/lysosomal membranes and subsequent the mitochondria membrane, which leads to apoptosis. This rational design of MLP-based conjugates provides a practical strategy to increase the application prospects of lytic peptides in cancer treatment.     

Mitochondria-targeting NIR fluorescent probe for rapid,highly sensitive and selective visualization of nitroxyl in live cells,tissues and mice

Nitroxyl(HNO)has been reported to possess unique biological and pharmacological performances,and emerged as a novel therapy for congestive heart failure.Recent studies also suggest that HNO may be produced and involved in important metabolisms in mitochondria.However,due to its high reactivity and short life properties,fast,sensitive and selective observation and monitoring of HNO related dynamic changes in mitochondria still remains a great challenge.Herein,we synthesized a mitochondria-targeting near-infrared(NIR)fluorescent probe(DCMHNO)for rapid detection of HNO with remarkably high sensitivity,selectivity and photostability.DCMHNO shows fast response(about 4 min)towards HNO via 2-(diphenylphosphino)benzoyl group through the Staudinger reaction to boost the bright NIR emission(700 nm)with excellent sensitivity(detection limit of 13 nM),high p H stability and very low interference from other species.DCMHNO can selectively locate in mitochondria and visualize exogenous and endogenous HNO in live He La cells with high biocompatibility and photostability.The probe could also monitor the interaction between NO and H2 S that gives rise to the generation of HNO in live He La cells.In addition,DCMHNO was further utilized in ex vivo NIR imaging of HNO in live mouse liver tissues at the depth of about 50μm.In vivo imaging of HNO with high signal-to-noise ratio in live mice was also realized by using DCMHNO.These remarkable imaging performances could render NIR DCMNHNO as a useful tool to reveal HNO related dynamic changes in live samples.