The AUTOTAC chemical biology platform for targeted protein degradation via the autophagy-lysosome system.

Targeted protein degradation allows targeting undruggable proteins for therapeutic applications as well as eliminating proteins of interest for research purposes. While several degraders that harness the proteasome or the lysosome have been developed, a technology that simultaneously degrades targets and accelerates cellular autophagic flux is still missing. In this study, we develop a general chemical tool and platform technology termed AUTOphagy-TArgeting Chimera (AUTOTAC), which employs bifunctional molecules composed of target-binding ligands linked to autophagy-targeting ligands. AUTOTACs bind the ZZ domain of the otherwise dormant autophagy receptor p62/Sequestosome-1/SQSTM1, which is activated into oligomeric bodies in complex with targets for their sequestration and degradation. We use AUTOTACs to degrade various oncoproteins and degradation-resistant aggregates in neurodegeneration at nanomolar DC50 values in vitro and in vivo. AUTOTAC provides a platform for selective proteolysis in basic research and drug development.

Neuroprotective effects of Magnoliae Flos extract in mouse hippocampal neuronal cells.

Magnoliae Flos (MF) is a traditional medicinal herb used for managing rhinitis, sinusitis and headache. The purpose of the present study was to determine the neuroprotective effect of MF against glutamate-induced oxidative stress and to assess the underlying mechanism. Glutamate is a major endogenous excitatory neurotransmitter in the brain and contributes to the development of neurodegenerative diseases by excessive activation. MF extract was subjected to a neuroprotective effect assay in HT22 mouse hippocampal cells. The mechanism underlying the neuroprotective effect of MF extract was evaluated by assaying reactive oxygen species (ROS) levels, intracellular Ca2+ levels, mitochondrial membrane potential, glutathione level and antioxidant enzyme activity in HT22 cells. MF extract significantly decreased glutamate-induced death of HT22 cells (80.83 ± 7.34% relative neuroprotection). MF extract reduced the intracellular ROS and Ca2+ levels and increased the glutathione level and glutathione reductase and glutathione peroxide activities. Moreover, MF extract attenuated the mitochondrial membrane potential in HT22 cells. These results suggested that MF extract exerts a neuroprotective effect against oxidative stress HT22 cells, which was mediated by its antioxidant activity.

Protective Effect of Water Extracted Spirulina maxima on Glutamate-induced Neuronal Cell Death in Mouse Hippocampal HT22 Cell.

INTRODUCTION: Spirulina maxima was used as important nutritional source in the Aztec civilization because it is rich in proteins and vitamins. It contains various antioxidants such as phycocyanin and flavonoids. Based on abundant antioxidants, S. maxima is known to possess anti-inflammatory effect, especially on neuronal cells. MATERIALS AND METHODS: S. maxima was extracted in water and contain of phycocyanin was identified by high-performance liquid chromatography. Cell viability test was performed with treatment of S. maxima extract. After, oxidative stress-related mechanisms were evaluated by detecting the accumulation of reactive oxygen species (ROS) and Ca2+ influx, and decrease of mitochondrial membrane potential (MMP) level. Then, the glutathione (GSH) related assays were conducted. RESULTS: The water extracted S. maxima exerted the neuroprotective activity by attenuating the ROS and Ca2+ formation, maintaining the MMP level, and protecting the activity of the antioxidant enzymes by increasing reduced GSH against oxidative stress compared to control. CONCLUSION: The results suggested that water extracted S. maxima showed powerful neuroprotective effect through the mechanism related to antioxidant activity, able to preventing the radical-mediated cell death. SUMMARY: Water extracted Spirulina maxima contains C-phycocyaninWater extracted Spirulina maxima exerts neuroprotective effect on HT22 cellTo investigate the protective mechanisms, reactive oxygen species, Ca2+, mitochondrial membrane potential, Glutathione-related assays were performed. Abbreviations used: ROS: Reactive oxygen species; MMP: Mitochondrial membrane potential; GSH: Glutathione; GSSG: Glutathione disulfide, oxidized glutathione; GPx: Glutathione peroxidase; GR: Glutathione reductase; DMEM: Dulbecco's modified Eagle's medium; FBS: Fetal bovine serum; DCF-DA: 2',7'-dichlorofluorescein diacetate; PBS: Phosphate buffered serum; Rho 123: Rhodamine 123; NADPH: Nicotinamide adenine dinucleotide phosphate; DTNB: 5,5'-dithiobis-2-nitrobenzoic acid, Ellman's reagent; GSSG-R: Glutathione disulfide reductase; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; DMSO: Dimethyl sulfoxide; HPLC: High-performance liquid chromatography.

Simultaneous Determination of Four Compounds, Campesterol, Emodin8-O-ß-D-Glucopyranoside, Quercetin, and Isoquercitrin in Reynoutria sachalinensis by High-performance Liquid Chromatography-Diode Array Detector.

BACKGROUND: Reynoutria sachalinensis is a well-known and used herbal medicine to treatment of arthralgia, jaundice, amenorrhea, coughs, carbuncles, and sores. OBJECTIVE: We have developed high-performance liquid chromatography analysis method for simultaneous determination of isolated four compounds, campesterol, emodin8-O-ß-D-glucopyranoside, quercetin, and isoquercitrin from R. sachalinensis is. MATERIALS AND METHODS: The four compounds were separated on Shiseido C18 column (S-5 µm, 4.6 mm I.D. ×250 mm) at a column temperature of 25°C. The mobile phase composed of water and methanol with gradient elution system, and flow rate is 1.0 ml/min. The detection wavelength was set at 205 nm. RESULTS: Validation of this analytical method was evaluated by linearity, precision, and accuracy test. This established method had good linearity (R2 > 0.997). The relative standard deviation values of intra- and inter-day testing were indicated that <2%, and accuracy is 91.66%-103.31% at intraday and 91.69%-103.31% at intraday. The results of recovery test were 92.60%-108.99%. CONCLUSION: In these results, developed method was accurate and reliable to the quality evaluation of campesterol, emodin 8-O-ß-D-glucopyranoside, quercetin, and isoquercitrin isolated from R. sachalinensis. SUMMARY: We have developed high-performance liquid analysis method for simultaneous determination of 4 compounds of Reynoutria sachalinensis. Abbreviations used: HPLC: High-performance liquid chromatography, DAD: Diode array detector, LOD: Limit of detection, LOQ: Limit of quantitation, ICH: International Conference on Harmonisation.

Neuroprotective compounds from Reynoutria sachalinensis.

Glutamate is a neurotransmitter in central nervous system. Overexpression of glutamate leads to oxidative stress, resulting in several neurodegenerative disorders that include Alzheimer's disease. The n-hexane fraction of stems and ethyl acetate (EtOAc) fraction of flowers of Reynoutria sachalinensis provide neuroprotection against glutamate-induced oxidative toxicity in HT22 cells. In this study, 1-decanol (1), ß-amyrin (2), dammaran-3ß-ol (3), campesterol (4), daucosterol (5), ergosterol peroxide (6), emodin 8-O-ß-D-glucopyranoside (7), quercetin (8) and isoquercitrin (9) were isolated from n-hexane fractions of stems and EtOAc fractions of flowers of R. sachalinensis. Their neuroprotective activity was evaluated by MTT assay. 1-Decanol, campesterol, ergosterol peroxide, quercetin and isoquercitrin exhibited neuroprotective activity. These compounds decreased reactive oxygen species level, showed anti-oxidant activity with DPPH radical and in a H2O2 scavenging assay. Therefore, the neuroprotective activity of 1-decanol, campesterol, ergosterol peroxide, quercetin and isoquercitrin are associated with antioxidant activity.

Neuroprotective effect of Aronia melanocarpa extract against glutamate-induced oxidative stress in HT22 cells.

BACKGROUND: Glutamate (an endogenous excitatory neurotransmitter) at high concentrations contributes to the development of neurodegenerative diseases. Aronia melanocarpa (A. melanocarpa) berries contain anthocyanins and have high antioxidant activities. In this study, we evaluated whether A. melanocarpa berries could protect neuronal cells against glutamate-induced oxidative stress. METHOD: A. melanocarpa berries exerted a protective effect against cytotoxicity in HT22 mouse hippocampal cells by MTT assay. We evaluated oxidative stress parameters including ROS level, intracellular Ca2+ level, glutathione level and antioxidant enzyme activity in HT22 cells to elucidate the mechanism of its neuroprotective effect. RESULTS: A. melanocarpa berries decreased glutamate-induced death of HT22 cells. In addition, A. melanocarpa berries reduced ROS and intracellular Ca2+ levels. Glutathione level, antioxidant enzymes, glutathione reductase and glutathione peroxide activities and mitochondrial membrane potential were also increased in HT22 cells. CONCLUSION: These results suggested that A. melanocarpa berries protected HT22 cells by exerting an antioxidant effect.

A highly porous metal-organic framework: structural transformations of a guest-free MOF depending on activation method and temperature.

A doubly interpenetrating porous metal-organic framework (SNU-77) has been synthesized from the solvothermal reaction of the extended carboxylic acid tris(4'-carboxybiphenyl)amine (H(3)TCBPA) and Zn(NO(3))(2)⋅6H(2)O in N,N-dimethylacetamide (DMA). SNU-77 undergoes single-crystal-to-single-crystal transformations during various activation processes, such as room-temperature evacuation, supercritical CO(2) drying, and high temperature evacuation, to afford SNU-77R, SNU-77S, and SNU-77H, respectively. These guest-free MOFs exhibited different fine structures with different window shapes and different effective window sizes at room temperature. Variable-temperature synchrotron single-crystal X-ray analyses reveal that the guest-free structure is also affected by changes in temperature. Despite the different fine structures, SNU-77R, SNU-77S, and SNU-77H show similar gas sorption properties due to the nonbreathing nature of the framework and an additional structural change upon cooling to cryogenic gas sorption temperature. SNU-77H exhibits a large surface area (BET, 3670 m(2) g(-1)), a large pore volume (1.52 cm(3) g(-1)), and exceptionally high uptake capacities for N(2), H(2), O(2), CO(2), and CH(4) gases.