Hispidulin Enhances Temozolomide (TMZ)-Induced Cytotoxicity against Malignant Glioma Cells In Vitro by Inhibiting Autophagy.

Temozolomide (TMZ), an oral alkylating agent, is the widely used first-line chemotherapeutic reagent for glioma in clinical practice. However, TMZ-induced autophagy is another cellular process favoring glioma cell survival. This study aimed to explore whether hispidulin can facilitate TMZ-induced cell death of glioma. The MTT assay showed that coadministration with hispidulin and TMZ could significantly decrease the viability of glioma U87MG cells. Meanwhile, hispidulin administration was also observed to promote TMZ-induced apoptosis. Furthermore, additional hispidulin treatment further elevated TMZ-induced expression of Bax, cleaved-caspase-9, and cleaved-caspase-3 protein but decreased Bcl-2 protein expression in U87MG cells. We also observed that hispidulin suppressed TMZ-induced autophagy to promote apoptosis, as showed by decreased AVOs and LC3B-I/II protein expression. These results collectively suggested that the combination of hispidulin and TMZ could improve the antitumor efficiency of TMZ against malignant gliomas.

The protective mechanism of protein kinase R to inhibit neuronal ferroptosis in cerebral injury from subarachnoid hemorrhage.

PURPOSE: To investigate the role and mechanism of protein kinase R (PKR) in subarachnoid hemorrhage (SAH)-mediated ferroptosis. METHODS: A rat SAH model was constructed and treated with PKR inhibitor C16 to observe SAH and neurological impairment in rats and to detect malonaldehyde (MDA), iron ions content, ferritin heavy polypeptide 1 (FTH1) and glutathione peroxidase 4 (GPX4), and other related ferroptosis indicators in brain tissue. RNA sequencing analysis was used to investigate the mechanism of PKR, affecting the ferroptosis network of SAH. RESULTS: SAH caused severe fundic hemorrhage, neurological impairment, MDA and iron ion accumulation, and significant decrease in GPX4 and FTH1 levels in rats. C16 treatment significantly improved the above signs caused by SAH. By RNA-seq analysis, brain tissue of SAH-treated rats with SAH and C16 differentially expressed mRNA target genes enriched in stress response and organic developmental signaling pathways. CONCLUSION: Inhibition of PKR may improve cerebral injury after SAH by inhibiting ferroptosis, and RNA sequencing staged its mechanism of action may be related to the stress response.

Development and Multi-Data Set Verification of an RNA Binding Protein Signature for Prognosis Prediction in Glioma.

Objective: Increasing evidence emphasizes the clinical implications of RNA binding proteins (RBPs) in cancers. This study aimed to develop a RBP signature for predicting prognosis in glioma. Methods: Two glioma datasets as training (n = 693) and validation (n = 325) sets were retrieved from the CGGA database. In the training set, univariate Cox regression analysis was conducted to screen prognosis-related RBPs based on differentially expressed RBPs between WHO grade II and IV. A ten-RBP signature was then established. The predictive efficacy was evaluated by ROCs. The applicability was verified in the validation set. The pathways involving the risk scores were analyzed by ssGSEA. scRNA-seq was utilized for evaluating their expression in different glioma cell types. Moreover, their expression was externally validated between glioma and control samples. Results: Based on 39 prognosis-related RBPs, a ten RBP signature was constructed. High risk score distinctly indicated a poorer prognosis than low risk score. AUCs were separately 0.838 and 0.822 in the training and validation sets, suggesting its well performance for prognosis prediction. Following adjustment of other clinicopathological characteristics, the signature was an independent risk factor. Various cancer-related pathways were significantly activated in samples with high risk score. The scRNA-seq identified that risk RBPs were mainly expressed in glioma malignant cells. Their high expression was also found in glioma than control samples. Conclusion: This study developed a novel RBP signature for robustly predicting prognosis of glioma following multi-data set verification. These RBPs may affect the progression of glioma.

Insight Into the Role of Ferroptosis in Non-neoplastic Neurological Diseases.

Ferroptosis is an iron-dependent form of cell death characterized by the accumulation of intracellular lipid reactive oxygen species (ROS). Ferroptosis is significantly different from other types of cell death including apoptosis, autophagy, and necrosis, both in morphology and biochemical characteristics. The mechanisms that are associated with ferroptosis include iron metabolism, lipid oxidation, and other pathophysiological changes. Ferroptosis inducers or inhibitors can influence its occurrence through different pathways. Ferroptosis was initially discovered in tumors, though recent studies have confirmed that it is also closely related to a variety of neurological diseases including neurodegenerative disease [Alzheimer's disease (AD), Parkinson's disease (PD), etc.] and stroke. This article reviews the definition and characteristics of ferroptosis, the potential mechanisms associated with its development, inducers/inhibitors, and its role in non-neoplastic neurological diseases. We hope to provide a theoretical basis and novel treatment strategies for the treatment of central nervous system diseases by targeting ferroptosis.

Hydrogen sulfide ameliorates subarachnoid hemorrhage-induced neuronal apoptosis via the ROS-MST1 pathway.

BACKGROUND: Hydrogen sulfide (H2S) has shown a neuroprotective role in several cerebrovascular diseases. This study aimed to explore the underlying mechanisms of H2S in early brain injury after subarachnoid hemorrhage (SAH). METHODS: One hundred seventy-seven male Sprague-Dawley rats were employed in this study. Sodium hydrosulfide (NaHS), a donor of H2S, was injected intraperitoneally at 60 min after SAH was induced by endovascular perforation. Western blot analysis determined the expression of several proteins of interest, and an immunofluorescence assay was used to examine neuronal apoptosis. RESULTS: Exogenous NaHS markedly improved neurological scores, attenuated brain edema, and ameliorated neuronal apoptosis at 24 h after SAH induction. The underlying mechanisms of H2S in ameliorating neuronal apoptosis might be executed through inhibition of the activity of mammalian sterile 20-like kinase 1 (MST1) protein. Western blot analysis demonstrated that exogenous NaHS decreased cleaved MST1 (cl-MST1) while increasing full-length MST1 expression. This anti-apoptotic effect of H2S could be reversed by chelerythrine, which could activate MST1 via caspase-dependent cleavage. CONCLUSIONS: Exogenous NaHS, as a donor of H2S, could ameliorate early brain injury after SAH by inhibiting neuronal apoptosis by reducing the activity of the MST1 protein.