IDH-mutated gliomas promote epileptogenesis through d-2-hydroxyglutarate-dependent mTOR hyperactivation.

BACKGROUND: Uncontrolled seizures in patients with gliomas have a significant impact on quality of life and morbidity, yet the mechanisms through which these tumors cause seizures remain unknown. Here, we hypothesize that the active metabolite d-2-hydroxyglutarate (d-2-HG) produced by the IDH-mutant enzyme leads to metabolic disruptions in surrounding cortical neurons that consequently promote seizures. METHODS: We use a complementary study of in vitro neuron-glial cultures and electrographically sorted human cortical tissue from patients with IDH-mutant gliomas to test this hypothesis. We utilize micro-electrode arrays for in vitro electrophysiological studies in combination with pharmacological manipulations and biochemical studies to better elucidate the impact of d-2-HG on cortical metabolism and neuronal spiking activity. RESULTS: We demonstrate that d-2-HG leads to increased neuronal spiking activity and promotes a distinct metabolic profile in surrounding neurons, evidenced by distinct metabolomic shifts and increased LDHA expression, as well as upregulation of mTOR signaling. The increases in neuronal activity are induced by mTOR activation and reversed with mTOR inhibition. CONCLUSION: Together, our data suggest that metabolic disruptions in the surrounding cortex due to d-2-HG may be a driving event for epileptogenesis in patients with IDH-mutant gliomas.

Associated factors of non-suicidal self-injury behavior in adolescents with depression disorder / 中国学校卫生

Objective@#To explore associated factors of non-suicidal self-injury in adolescents with depression, and to provide a reference for clinical intervention and treatment.@*Methods@#A cross-sectional survey was conducted among 80 adolescents aged 14-18 years with depressive disorder who visited an outpatient clinic in the PLA 904nd Hospital from January 2015 to January 2017. Eysenck Personality Questionnaire(EPQ), Egma Minnenav Bsrdndosnauppforstran (EMBU), non-suicidal self-injury behavior rating scale were used to investigate them.@*Results@#Male patients with depression had more non-suicidal self-injury than female patients(76.74% vs. 54.05%), and patients with highly educated mothers had more non-suicidal self-injury(77.78%)(χ 2=4.58, 6.11, P<0.05). Self-injury behavior in patients with internal and external (E) the orientation factor score (5.22±2.82) was lower than the score of the patients without self-injury behavior(8.85±2.93)(t=-5.37, P<0.05), neuroticism (N), while psychoticism (P) and hide(L) score [(14.53±3.94) (5.60±1.58) (12.94±0.54)] were higher than patients without self-injury behavior [(11.55±5.71) (3.13±1.43) (12.09±0.55)](t=2.74, 6.82, 6.31, P<0.05); Factors such as "severe paternal punishment" "paternal excessive interference" "paternal refusal to deny" "maternal refusal to deny" and other factors in patients with non-suicidal self-injury [(21.57±4.65) (21.73±4.38) (14.25±5.08) (20.34±4.64)] were all higher than those without nonsuicidal self-injury [(18.50±7.53) (18.77±3.55) (11.58±2.97) (16.55±6.32)](t=2.25, 3.04, 2.96, 3.05, P<0.05); Logistic regression analysis showed that males, mothers with high educational level, and E, N, P (<38.5 and >61.5) were associated with non-suicidal self-injury behavior in adolescents with depression(OR=1.99, 2.31, 1.71, 2.52, 1.98, P<0.05).@*Conclusion@#Gender, maternal education and symptom score were the important factors influencing non-suicidal self-injury.It is necessary to arouse the attention of the family, society and school.

Metabolic plasticity of IDH1-mutant glioma cell lines is responsible for low sensitivity to glutaminase inhibition.

BACKGROUND: Targeting glutamine metabolism in cancer has become an increasingly vibrant area of research. Mutant IDH1 (IDH1 mut ) gliomas are considered good candidates for targeting this pathway because of the contribution of glutamine to their newly acquired function: synthesis of 2-hydroxyglutarate (2HG). METHODS: We have employed a combination of 13C tracers including glutamine and glucose for investigating the metabolism of patient-derived IDH1 mut glioma cell lines through NMR and LC/MS. Additionally, genetic loss-of-function (in vitro and in vivo) approaches were performed to unravel the adaptability of these cell lines to the inhibition of glutaminase activity. RESULTS: We report the adaptability of IDH1 mut cells' metabolism to the inhibition of glutamine/glutamate pathway. The glutaminase inhibitor CB839 generated a decrease in the production of the downstream metabolites of glutamate, including those involved in the TCA cycle and 2HG. However, this effect on metabolism was not extended to viability; rather, our patient-derived IDH1 mut cell lines display a metabolic plasticity that allows them to overcome glutaminase inhibition. CONCLUSIONS: Major metabolic adaptations involved pathways that can generate glutamate by using alternative substrates from glutamine, such as alanine or aspartate. Indeed, asparagine synthetase was upregulated both in vivo and in vitro revealing a new potential therapeutic target for a combinatory approach with CB839 against IDH1 mut gliomas.

Recent Advances in Sensitive Detection of Kinases / 分析化学

Kinases are a class of enZymes that catalyZe the transfer of a phosphate group from a high-energy molecule to their substrates ( i.e., phosphorylation ).Kinase-induced intracellular phosphorylation plays important roles in a variety of cellular processes including metabolism, cell signaling, protein regulation, DNA replication and repair.Consequently, kinases have become potential biomarkers for disease diagnosis and drug discovery, and the development of simple and sensitive methods for kinase assay is highly desirable.In this review, we summariZe the recent advances in kinase assays with protein kinase A (PKA), casein kinase-2 ( CKⅡ) and T4 polynucleotide kinase ( T4 PNK) as the models.We focus on the newly emerging methods for kinase assays including fluorescent, single-molecule detection, colorimetric, chemiluminescent, bioluminescent, and electrochemical and photoelectrochemical methods.Furthermore, we give a new insight into the future direction of kinase assays.

A new specialization in astrocytes: glutamate- and ammonia-induced nuclear size changes.

We observed nuclear swelling in glutamate (Glu)-treated astrocytes that was concomitant with but independent of astrocytic cell swelling. We confirmed Glu-induced nuclear swelling with nuclei isolated from astrocytes. Ammonia is metabolically related to Glu and could induce a nuclear swelling in intact astrocytes but shrinkage in isolated nuclei. Other compounds such as glutamine, aspartate, taurine, glycine, and ATP did not cause any nuclear swelling in isolated nuclei of astrocytes. Surprisingly, Glu and ammonia did not induce nuclear swelling in microglia, C6, HEK 293, or Hep G2 cell lines in cultures and their isolated nuclei. The Glu- and ammonia-induced nuclear size changes appear to be a specific response of astrocytes to these two closely related metabolic compounds.

Ischemia activates JNK/c-Jun/AP-1 pathway to up-regulate 14-3-3gamma in astrocyte.

Ischemia occurs in the brain as the result of stroke and other related injuries and few therapies are effective. If more is understood then potential treatments could be investigated. It was previously reported that 14-3-3gamma could be up-regulated by ischemia in astrocyte to protect cells from ischemia-induced apoptosis. In this study, we attempted to uncover the mechanism responsible for this 14-3-3gamma up-regulation in primary culture of astrocytes under ischemic-like conditions. It was found that in vitro ischemia may activate PI3K/Akt and MAPK signaling pathways. Astrocyte cultures were treated with LY294002 (PI3K inhibitor), U0126 (ERK inhibitor), SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor). Only SP600125 could inhibit the ischemia-induced 14-3-3gamma up-regulation in astrocytes. At the same time, we observed an ischemia-induced nuclear translocation of p-c-Jun, a major downstream component of JNK. Inhibition of AP-1 with curcumin also inhibited 14-3-3gamma up-regulation indicating that ischemia-induced up-regulation of 14-3-3gamma in astrocyte involves activation of the JNK/p-c-Jun/AP-1 pathway.

Astrocyte and neuron intone through glutamate.

The unexpected finding of astrocytes to release glutamate as gliotransmitter challenges the traditional concepts on astrocyte being "passive" in CNS communications. Glutamate is the major excitatory transmitter in transferring information between neurons, but is now also known to activate astrocyte through transporters and receptors. Together with the sensitive swelling response, astrocytes could respond directly to glutamate and neuronal activity. Other new functions of astrocytes include modulation of synaptic plasticity and cerebral blood flow (CBF). The classic glutamate deplenishment through glutamine synthesis and CO(2) production does not account for the total glutamate internalized into astrocytes. This leads us to speculate there are many hidden functions of glutamate in neurons and astrocytes waiting to be discovered. In this review, we attempted to reexamine some of these new and older functions of glutamate and to reevaluate the roles of glutamate intoning these two cell types.

The presence of active Cdk5 associated with p35 in astrocytes and its important role in process elongation of scratched astrocyte.

Cyclin-dependent kinase 5 (Cdk5) is a unique member of the Cdk family; its kinase activity requires association with its activator, p35 or p39. p35 is the strongest and best characterized activator. Previous studies showed that p35 is a neuron-specific protein that restricts Cdk5 activity in neurons. However, a high expression level of Cdk5 is found in astrocytes, which raises the possibility that astrocytic Cdk5 is functional. Here we show the presence of functional Cdk5 associated with p35 in astrocytes and demonstrate its important role in process elongation of scratched astrocytes. We found that p35 and glial fibrillary acidic protein (GFAP) were co-localized in primary cultured and acute isolated brain cells. Cdk5 could form an immunocomplex with p35 and its activity was shown in pure primary cultured astrocytes. p35 was upregulated in astrocytes injured by scratching, concomitantly with upregulation of Cdk5 kinase activity. Pretreatment of the scratched astrocytes with a Cdk5 inhibitor, roscovitine, could delay wound healing by inhibiting the reorganization of tubulin, GFAP, and the extension of hypertrophic processes. Moreover, overexpression of dominant negative Cdk5 could shorten the length of extending protrusion of reactive astrocytes. Thus, our findings demonstrated that functional Cdk5, associated with p35, was expressed in astrocytes and its activity could be upregulated in reactive astrocytes, a new role of Cdk5 that has never been reported in the nervous system. The present study may provide new insight for understanding the multifunctional protein complex Cdk5/p35 in the nervous system.