Baicalein attenuates rotenone-induced SH-SY5Y cell apoptosis through binding to SUR1 and activating ATP-sensitive potassium channels

MgATPase Activity is Dispensable for the Pharmacological Regulation of the Functional Effects of the KATP Channels Opening in Brain Mitochondria

BACKGROUND

The mechanisms underlying the effects of pharmacological mitochondrial ATP-sensitive K+ channel (mKATP) channel openers on the functional effects of the mKATP channels opening remain disputable. Earlier we have shown that the mKATP channel activation by diazoxide (DZ) occurred at submicromolar concentrations and did not require a MgATP in liver mitochondria. This work aimed to evaluate a requirement of a MgATP for the mKATP channel opening by DZ and its blocking by glibenclamide (Glb) and 5-hydroxy decanoate (5-HD) in rat brain mitochondria and to find the effects of the mKATP channels opening on mitochondrial Ca2+ uptake, reactive oxygen species (ROS) production, and the mitochondrial permeability transition pore (mPTP).

METHODS

The mKATP and the mPTP channels activity was assessed by the light scattering; polarography was applied to quantify K+ transport; Ca2+ transport and ROS production were monitored with fluorescent probes, chlortetracycline, and dichlorofluorescein, respectively; one-way ANOVA was used for reliability testing.

RESULTS

ATP-sensitive K+ transport in native mitochondria was fully activated by DZ at <0.5 μM and blocked by Glb and 5-HD in the absence of a MgATP, however, Mg2+ was indispensable for the blockage of the mKATP channel by ATP. DZ increased Ca2+ uptake, but ROS production was regulated differently: suppressed in mitochondria respiring on glutamate, but activated on succinate. However, in the presence of rotenone, ROS production was suppressed by DZ, which indicated the involvement of reverse electron transport (RET) in the modulation of ROS production. In all cases, the mKATP channel blockers reversed the effects of DZ. The impact of DZ on the mPTP opening strongly correlated with its effects on ROS production. DZ inhibited the mPTP activity on glutamate but elevated on succinate, which was strongly suppressed by rotenone. In the presence of rotenone, the mPTP was strongly inhibited by DZ, which indicated the involvement of ROS and RET in the mechanism of mPTP regulation by DZ.

CONCLUSIONS

Brain mKATP channel exhibited high sensitivity to DZ on the low sub-micromolar scale; its regulation by DZ and Glb did not require a MgATPase activity; the impact of DZ on the mPTP activity was critically dependent on the regulation of ROS production by ATP-sensitive K+ transport.

Study on the Molecular Mechanism of Baicalin Phosphorylation of Tau Protein Content in a Cell Model of Intervention Cognitive Impairment

Objective

This study aimed to predict the molecular mechanism of baicalein through network pharmacology, cell experiments and molecular docking. The goal was to elucidate the mechanism for the treatment of mild cognitive impairment.

Materials and Methods

The protein-protein interaction network (PPI) and Cytoscape software were used to screen the hub genes of intersection genes, while the therapeutic mechanism of baicalein was predicted through the Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) enrichment analysis. Molecular docking of the core target and baicalein was conducted using AutoDock software. The neuroprotective effect of Baicalein with different concentrations on okadaic acid-treated SH-SY5Y cells was investigated in cell experiments. Scratch experiments were conducted to explore the effect of baicalein on cell migration ability, and enzyme linked immunosorbent assay was employed to measure the content of extracellular pathological proteins. Western Blot and Cellular immunofluorescence pinpointed differences in the relevant protein content.

Results

Enrichment analysis revealed significant enrichment in the PI3K-Akt signaling pathway, and molecular docking demonstrated a favorable binding energy between baicalein and AKT1. In cell experiments, baicalein presented a positive impact on mild cognitive impairment by elevating P-AKT1 and P-GSK-3β levels while reducing the overall amount of P-tau.

Conclusion

As demonstrated by the present study, the low concentration of baicalein (15μmol/L) effectively managed the mild cognitive impairment by regulating the phosphorylation of AKT1 and GSK-3β.

Accurate identification of 8-oxoguanine in RNA with single-nucleotide resolution using ligase-dependent qPCR

8-oxoguanine (o8G), a prevalent oxidative modification in RNA induced by reactive oxygen species (ROS), plays a pivotal role in regulating RNA functions. Accurate detection and quantification of o8G modifications is critical to understanding their biological significance and potential as disease biomarkers, but effective detection methods remain limited. Here, we have developed a highly specific T3 DNA ligase-dependent qPCR assay that exploits the enzyme's ability to discriminate o8G from guanine (G) with single-nucleotide resolution. This method can detect o8G in RNA at levels as low as 500 fM, with an up to 18-fold higher selectivity for discriminating o8G from G. By simulating oxidative stress conditions in SH-SY5Y and HS683 cell lines treated with rotenone, we successfully identified site-specific o8G modifications in key miRNAs associated with neuroprotective responses, including miR-124, let-7a and miR-29a. The developed assay holds significant promise for the practical identification of o8G, facilitating its potential for detailed studies of o8G dynamics in various biological contexts and diseases.