Thiol-Chromene "Click" Reaction Triggered Self-Immolative for NIR Visualization of Thiol Flux in Physiology and Pathology of Living Cells and Mice.

Understanding the pathological process of biological systems can greatly improve the prevention and treatment of diseases. The study of pathological processes has now reached the molecular level, and molecular fluorescent probes have become a powerful tool. Chromene, also known as benzo-pyran molecule, is a structural element of natural products with good biological compatibility and was developed as a fluorescent probe. The thiol-chromene "click" nucleophilic pyran ring-opening reaction allows the quick detection of thiol. In this work, the chromene alcohol can function as an efficient self-immolative spacer, which covalently links NIR fluorophore via a carbonyl ester. Due to its favorable characteristics and superior applicability, the self-immolative amplifier NIR-HMPC achieves the specific, rapid, sensitive, NIR fluorescent detection of thiols. Furthermore, the indoles iodized salt in the system can specifically target thiols in mitochondria. Thus, this probe was used to visualize the fluctuations of thiols during oxidative stress and cell apoptosis, cerebral ischemia reperfusion, demonstrating that it is valuable for elucidating pathophysiology process in living organism. This discovery provides an effective means for studying the pathological process of thiol related diseases.

Naringin Dihydrochalcone Ameliorates Cognitive Deficits and Neuropathology in APP/PS1 Transgenic Mice.

Alzheimer's disease (AD) is a multi-factorial neurodegenerative disorder with abnormal accumulation of amyloid-ß (Aß) plaques, neuroinflammation and impaired neurogenesis. Mounting evidences suggest that single-target drugs have limited effects on clinical treatment and alternative or multiple targets are required. In recent decades, natural compounds and their derivatives have gained increasing attention in AD drug discovery due to their inherently enormous chemical and structural diversity. In this study, we demonstrated that naringin dihydrochalcone (NDC), a widely used dietary sweetener with strong antioxidant activity, improved the cognitive function of transgenic AD mice. Pathologically, NDC attenuated Aß deposition in AD mouse brain. Furthermore, NDC reduced periplaque activated microglia and astrocytes, indicating the inhibition of neuroinflammation. It also enhanced neurogenesis as investigated by BrdU/NeuN double labeling. Additionally, the inhibition of Aß level and neuroinflammation by NDC treatment was also observed in an AD cell model or a microglia cell line. Taken together, our study indicated that NDC might be a potential therapeutic agent for the treatment of AD against multiple targets that include Aß pathology, neuroinflammation and neurogenesis.

EGCG decreases the expression of HIF-1α and VEGF and cell growth in MCF-7 breast cancer cells.

PURPOSE: To investigate the effects of epigallocatechin-3-gallate (EGCG) on the expression of HIF-1α and vascular endothelial growth factor (VEGF) and cell growth in MCF-7 breast cancer cells. METHODS: MCF-7 human breast cancer cells were pretreated with different concentrations of EGCG (25, 50, 100 mg/L) for 48 h. The growth and proliferation of cells were analyzed by trypan blue staining in the pretreated MCF-7 cells. Furthermore, mRNA expression of HIF-1α and VEGF was detected by reverse transcriptase polymerase chain reaction (RT-PCR) analysis in the pretreated MCF-7 cells. Protein expression of HIF-1α was detected by Western blot, and the secreted protein level of VEGF in the supernatant of the culture medium was analyzed by enzyme linked immuno- sorbent assay (ELISA) in the MCF-7 cells pretreated with different concentrations of EGCG. RESULTS: Cell growth decreased dramatically in MCF-7 cells treated with different concentrations of EGCG, compared with untreated (control) cells. Moreover, protein expression of HIF-1α and VEGF declined in a dose-dependent manner in MCF-7 cells pretreated with increasing concentrations of EGCG. CONCLUSIONS: EGCG inhibits cell growth and proliferation of MCF-7 breast cancer cells, possibly by inhibiting the protein expression of HIF-1α and VEGF.