Photocontrollable Probes for Mitochondrial Protein Profiling.

The mitochondrion is the core site of cell signaling, energy metabolism and biosynthesis. Here, taking advantage of activity-based probes, we synthesized two photocontrollable probes (YGH-1 and YGH-2), composed of a mitochondrial localization moiety "triphenylphosphonium", a photo-triggered group to achieve spatially and temporally controlled protein capture, and an alkyne group to enrich the labeled protein. Proteomic validation was further carried out to facilitate identification of the mitochondrial proteome in HeLa cells. The results show that half of the identified protein hits (∼300) labeled by YGH-1 and YGH-2 belong to mitochondria, and are mostly localized in the mitochondrial matrix and inner mitochondrial membrane. Our results provide a new tool for spatial and temporal analysis of subcellular proteomes.

EEG-based Major Depressive Disorder Detection Using Data Mining Techniques.

Major depressive disorder (MDD) is a common mental illness characterized by a persistent feeling of low mood, sadness, fatigue, despair, etc.. In a serious case, patients with MDD may have suicidal thoughts or even suicidal behaviors. In clinical practice, a widely used method of MDD detection is based on a professional rating scale. However, the scale-based diagnostic method is highly subjective, and requires a professional assessment from a trained staff. In this work, 92 participants were recruited to collect EEG signals in the Shenzhen Traditional Chinese Medicine Hospital, assessing MDD severity with the HAMD-17 rating scale by a trained physician. Two data mining methods of logistic regression (LR) and support vector machine (SVM) with derived EEG-based beta-alpha-ratio features, namely LR-DF and SVM-DF, are employed to screen out patients with MDD. Experimental results show that the presented the LR-DF and SVM-DF achieved F 1 scores of 0:76 0:30 and 0:92 0:18, respectively, which have obvious superiority to the LR and SVM without derived EEG-based beta-alpha-ratio features.

Design, synthesis and evaluation of protein disulfide isomerase inhibitors with nitric oxide releasing activity.

Protein disulfide isomerase (PDI), a chaperone protein mostly in endoplasmic reticulum, catalyzes disulfide bond breakage, formation, and rearrangement to promote protein folding. PDI is regarded as a new target for treatment of several disorders. Here, based on the combination principle, we report a new PDI reversible modulator 16F16A-NO by replacing the reactive group in a known PDI inhibitor 16F16 with nitric oxide (NO) donor. Using molecular docking experiment, 16F16A-NO could embed into the active cavity of PDI. From newly developed fluorescent assay, 16F16A-NO showed rapid NO release. Furthermore, it is capable to moderately inhibit activity of PDI and S-nitrosylate the protein, indicating by insulin aggregation assay and biotin-switch technique. Finally, it displayed a dose-dependent antiproliferative activity against SH-SY5Y and HeLa tumor cells. Our designed hybrid compound 16F16A-NO showed a reasonable activity and might offer a promising avenue to develop novel PDI inhibitors for disease treatments.

Recent advances in reaction-based fluorescent probes for detecting monoamine oxidases in living systems.

Monoamine oxidase (MAO) is a membrane-bound mitochondrial enzyme that plays an important role by catalyzing oxidative deamination to maintain the homeostasis of neurotransmitters and other biogenic amines in living systems. MAO activity is critical for the brain and central nervous system. Its dysfunction is closely related with many neurological and psychiatric disorders. Fluorescent probes provide a useful approach to accurately detect MAO activity and assist to better elucidate their biological functions. Herein, in this Minireview, we summarize the recent advances in reaction based MAO type fluorescent probes and their imaging applications in living systems.

Differently Tagged Probes for Protein Profiling of Mitochondria.

The mitochondrion is one of the most important organelles in the eukaryotic cell. Characterization of the mitochondrial proteome is a prerequisite for understanding its cellular functions at the molecular level. Here we report a proteomics method based on mitochondrion-targeting groups and click chemistry. In our strategy, three different mitochondrion-targeting moieties were each augmented with a clickable handle and a cysteine-reactive group. Fluorescence-based bioimaging and fractionation experiments clearly showed that most signals arising from the labels were localized in the mitochondria of cells, as a result of covalent attachment between probe and target proteins. The three probes had distinct profiling characteristics. Furthermore, we successfully identified more than two hundred mitochondrial proteins. The results showed that different mitochondrion-targeting groups targeted distinct proteins with partial overlap. Most of the labeled proteins were localized in the mitochondrial matrix and inner mitochondrial membrane. Our results provide a tool for chemoproteomic analysis of mitochondrion-related proteins.

A dual functional fluorogenic probe for visualization of intracellular pH and formaldehyde with distinct fluorescence signals.

In this study, a single fluorescent probe (DPFP) containing a 1,8-naphthalimide dye and a homoallylamino group for imaging pH and formaldehyde (FA) has been developed that exhibits significant blue fluorescence (λem at 455 nm) under acidic pH conditions (pH < 7.0) and green fluorescence (λem at 555 nm) in the presence of FA, respectively. Furthermore, probe DPFP was successfully applied to image acidic lysosomes and exogenous or endogenous FA in living HeLa cells.