Protective autophagy alleviates neurotoxin-gelsenicine induced apoptosis through PERK signaling pathway in Neuro-2a cells

Decoding gelsenicine-induced neurotoxicity in mice via metabolomics and network toxicology

BACKGROUND

Gelsenicine, the most toxic constituent of Gelsemium elegans Benth., is known for its diverse pharmacological activities alongside potent neurotoxicity, frequently leading to poisoning incidents following mistaken ingestion. However, its molecular mechanisms remain largely unexplored.

PURPOSE

This study aimed to elucidate the key mechanistic network underlying gelsenicine-induced neurotoxicity by employing a comprehensive strategy that integrated metabolomics, network toxicology, molecular docking, and experimental validation.

METHODS

Acute oral toxicity tests were conducted in C57BL/6J mice to assess toxic symptoms, determine the median lethal dose (LD50), and evaluate histopathological changes. Untargeted metabolomics was performed to identify differential metabolites and associated pathways in serum, hippocampus (HIP), and medulla oblongata (MO). Integration of network toxicology pinpointed core targets and pathways, which were further validated through molecular docking and RT-qPCR. A core "compound-target-metabolite-pathway" network involved in gelsenicine-induced neurotoxicity was established.

RESULTS

Gelsenicine exhibited an oral LD50 of approximately 1.82 mg/kg and induced neurotoxic damage in the HIP and MO. Two untargeted metabolomic approaches detected a broad range of metabolites, revealing that gelsenicine markedly altered the metabolic profiles of serum, HIP, and MO. Network toxicology analysis identified 187 key targets associated with gelsenicine neurotoxicity. Integrated analyses with the predicted targets of differential metabolites indicated that gelsenicine primarily interferes with the energy metabolism network centered on the malate-aspartate shuttle (MAS), affecting pathways such as carbon metabolism, amino acid metabolism, TCA cycle, and PPAR signaling pathway. Malate, glutamate, and aspartate were identified as core metabolites and potential biomarkers of gelsenicine poisoning. RT-qPCR validation revealed that gelsenicine interfered with the expression of core targets, including GLUD1, MDH, GOT and ME, all of which exhibited good binding energy with gelsenicine.

CONCLUSION

This study unveiled a novel mechanistic insight into gelsenicine-induced neurotoxicity, demonstrating its capacity to perturb multiple energy metabolism pathways associated with MAS. These findings could enhance the theoretical understanding of gelsenicine's neurotoxic effects and highlight potential applications in clinical diagnosis and forensic identification.

RACK1 promotes autophagy via the PERK signaling pathway to protect against traumatic brain injury in rats

AIMS

Neuronal cell death is a primary factor that determines the outcome after traumatic brain injury (TBI). We previously revealed the importance of receptor for activated C kinase (RACK1), a multifunctional scaffold protein, in maintaining neuronal survival after TBI, but the specific mechanism remains unclear. The aim of this study was to explore the mechanism underlying RACK1-mediated neuroprotection in TBI.

METHODS

TBI model was established using controlled cortical impact injury in Sprague-Dawley rats. Genetic intervention and pharmacological inhibition of RACK1 and PERK-autophagy signaling were administrated by intracerebroventricular injection. Western blotting, coimmunoprecipitation, transmission electron microscopy, real-time PCR, immunofluorescence, TUNEL staining, Nissl staining, neurobehavioral tests, and contusion volume assessment were performed.

RESULTS

Endogenous RACK1 was upregulated and correlated with autophagy induction after TBI. RACK1 knockdown markedly inhibited TBI-induced autophagy, whereas RACK1 overexpression exerted the opposite effects. Moreover, RACK1 overexpression ameliorated neuronal apoptosis, neurological deficits, and cortical tissue loss after TBI, and these effects were abrogated by the autophagy inhibitor 3-methyladenine or siRNAs targeting Beclin1 and Atg5. Mechanistically, RACK1 interacted with PERK and activated PERK signaling. Pharmacological and genetic inhibition of the PERK pathway abolished RACK1-induced autophagy after TBI.

CONCLUSION

Our findings indicate that RACK1 protected against TBI-induced neuronal damage partly through autophagy induction by regulating the PERK signaling pathway.

Reference Genes Screening and Gene Expression Patterns Analysis Involved in Gelsenicine Biosynthesis under Different Hormone Treatments in Gelsemium elegans

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is an accurate method for quantifying gene expression levels. Choosing appropriate reference genes to normalize the data is essential for reducing errors. Gelsemium elegans is a highly poisonous but important medicinal plant used for analgesic and anti-swelling purposes. Gelsenicine is one of the vital active ingredients, and its biosynthesis pathway remains to be determined. In this study, G. elegans leaf tissue with and without the application of one of four hormones (SA, MeJA, ETH, and ABA) known to affect gelsenicine synthesis, was analyzed using ten candidate reference genes. The gene stability was evaluated using GeNorm, NormFinder, BestKeeper, ∆CT, and RefFinder. The results showed that the optimal stable reference genes varied among the different treatments and that at least two reference genes were required for accurate quantification. The expression patterns of 15 genes related to the gelsenicine upstream biosynthesis pathway was determined by RT-qPCR using the relevant reference genes identified. Three genes 8-HGO, LAMT, and STR, were found to have a strong correlation with the amount of gelsenicine measured in the different samples. This research is the first study to examine the reference genes of G. elegans under different hormone treatments and will be useful for future molecular analyses of this medically important plant species.