The neuroplastic index p-FADD/FADD and phosphoprotein PEA-15, interacting at GABAA receptor, are upregulated in brain cortex during midazolam-induced hypnosis in mice

Discovery of Biomarkers and Potential Mechanisms of Agarwood Incense Smoke Intervention by Untargeted Metabolomics and Network Pharmacology

Background

Agarwood, as a traditional Chinese medicine, has great potential value for the treatment of tranquilization. However, its potential mechanisms and biomarkers are still unclear.

Methods

In this study, ultra-high performance liquid chromatography-quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS)-based metabonomics was adopted to discover the potential biomarkers in mice after agarwood incense smoke (AIS) intervention. Furthermore, the chemical components in agarwood were identified based on UHPLC-Q-Exactive Orbitrap-MS. The global view of potential compound-target-pathway (C-T-B) network was constructed through network pharmacology to understand the potentially material basis of biomarkers.

Results

Metabolic profiling indicated that the metabolic changed significantly in mice serum after AIS intervention. A total of 18 potential biomarkers closely related to insomnia and emotional disease were identified, mainly involving in tryptophan metabolism, arginine and proline metabolism, cysteine and methionine metabolism and steroid hormone biosynthesis pathways. A total of 138 components in agarwood were identified based on UHPLC-Q-Exactive Orbitrap-MS. The results showed that mainly compounds such as flidersia type 2-(2-phenylethyl) chromones (FTPECs) and sesquiterpenes exerted good docking abilities with key target proteins, which were involved in multiple diseases including depression and hypnosis.

Conclusion

In conclusion, this study enhanced current understanding of the change of metabolic markers after AIS intervention. Meanwhile, it also confirmed the feasibility of combining metabolomics and network pharmacology to identify active components and elucidate the material basis of biomarkers and mechanisms.

Implications on hypnotherapy: Neuroplasticity, epigenetics and pain

We provide a brief review about the significance of hypnosis with respect to applications and physiological processes in hypnotherapy. Our review concludes that hypnosis is a promising method to manage acute and chronic pain. In addition, we discuss indications pointing toward the view that hypnosis can induce changes in neuroplasticity possibly involving epigenetic mechanisms.

Uncovering the pharmacological mechanism of the effects of the Banxia-Xiakucao Chinese Herb Pair on sleep disorder by a systems pharmacology approach

Sleep disorder (SD) has a high incidence and seriously affects quality of life, mental health and even the manifestation of physical diseases. The combination of Pinellia ternata (Chinese name: banxia) and Prunella vulgaris (Chinese name: xiakucao), known as the Banxia-Xiakucao Chinese herb pair (BXHP), is a proven Chinese herbal medicine that has been used to treat SD for thousands of years due to its significant clinical effects. However, its active pharmacological components and sedative-hypnotic mechanisms have not been fully elucidated. Thus, the present study used a systematic pharmacological approach to develop pharmacokinetic screens and target predictions via construction of a protein-protein interaction network and annotation database for SD-related and putative BXHP-related targets. Visualization, screening and integrated discovery enrichment analyses were conducted. The BXHP chemical database contains 166 compounds between the two herbal ingredients, and of these, 22 potential active molecules were screened by pharmacokinetic evaluation. The targets of 114 of the active molecules were predicted, and 34 were selected for further analysis. Finally, gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that BXHP can reduce inflammatory responses. and mediate immune-related and central nervous system neurotransmitters via regulation of multiple targets and pathways. The use of a systematic pharmacology-based approach in the present study further elucidated the mechanisms of action underlying BXHP for the treatment of SD from a holistic perspective and sheds light on the systemic mechanisms of action of Chinese herbal medicines in general.

KLF4 Exerts Sedative Effects in Pentobarbital-Treated Mice

KLF4 is a zinc-finger transcription factor that plays an essential role in many biological processes, including neuroinflammation, neuron regeneration, cell proliferation, and apoptosis. Through effects on these processes, KLF4 has likely roles in Alzheimer's disease, Parkinson's disease, and traumatic brain injury. However, little is known about the role of KLF4 in more immediate behavioral processes that similarly depend upon broad changes in brain excitability, such as the sleep process. Here, behavioral approaches, western blot, and immunohistochemical experiments were used to explore the role of KLF4 on sedation and the potential mechanisms of those effects. The results showed that overexpression of KLF4 prolonged loss of righting reflex (LORR) duration in pentobarbital-treated mice and increased c-Fos expression in the lateral hypothalamus (LH) and the ventrolateral preoptic nucleus (VLPO), while it decreased c-Fos expression in the tuberomammillary nucleus (TMN). Moreover, overexpression of KLF4 reduced the expression of p53 in the hypothalamus and increased the expression of STAT3 in the hypothalamus. Therefore, these results suggest that KLF4 exerts sedative effects through the regulation of p53 and STAT3 expression, and it indicates a role of KLF4 ligands in the treatment of sleep disorders.

Hypothermia: Impact on plasticity following brain injury

Therapeutic hypothermia (TH) is a potent neuroprotectant against multiple forms of brain injury, but in some cases, prolonged cooling is needed. Such cooling protocols raise the risk that TH will directly or indirectly impact neuroplasticity, such as after global and focal cerebral ischemia or traumatic brain injury. TH, depending on the depth and duration, has the potential to broadly affect brain plasticity, especially given the spatial, temporal, and mechanistic overlap with the injury processes that cooling is used to treat. Here, we review the current experimental and clinical evidence to evaluate whether application of TH has any adverse or positive effects on postinjury plasticity. The limited available data suggest that mild TH does not appear to have any deleterious effect on neuroplasticity; however, we emphasize the need for additional high-quality preclinical and clinical work in this area.

Ketamine-induced hypnosis and neuroplasticity in mice is associated with disrupted p-MEK/p-ERK sequential activation and sustained upregulation of survival p-FADD in brain cortex: Involvement of GABAA receptor

Ketamine (KET) is an antidepressant and hypnotic drug acting as an antagonist at excitatory NMDA glutamate receptors. The working hypothesis postulated that KET-induced sleep in mice results in dysregulation of mitogen-activated protein kinases (MAPK) MEK-ERK sequential phosphorylation and upregulation of survival p-FADD and other neuroplastic markers in brain. Low (5-15 mg/kg) and high (150 mg/kg) doses of KET on target proteins were assessed by Western immunoblot in mouse brain cortex. During the time course of KET (150 mg/kg)-induced sleep (up to 50 min) p-MEK was increased (up to +79%) and p-ERK decreased (up to -46%) indicating disruption of MEK to ERK signal. Subhypnotic KET (5-15 mg/kg) also revealed uncoupling of p-MEK (+13-81%) to p-ERK (unchanged content). KET did not alter contraregulatory MAPK mechanisms such as inactivated p-MEK1 (ERK dampening) and phosphatases MKP1/2/3 (ERK dephosphorylation). As other relevant findings, KET (5, 15 and 150 mg/kg) upregulated p-FADD in a dose-dependent manner, and for the hypnotic dose the effect paralleled the time course of sleep which resulted in increased p-FADD/FADD ratios. KET (150 mg/kg) also increased NF-κΒ and PSD-95 neuroplastic markers. Flumazenil (a neutral allosteric antagonist at GABA_A receptor) prolonged KET sleep and blocked p-MEK upregulation, indicating the involvement of this receptor as a negative modulator. SL-327 (a MEK inhibitor) augmented KET sleep, further indicating the relevance of reduced p-ERK1/2 in KET-induced hypnosis. These findings suggest that hypnotic and subhypnotic doses of KET inducing uncoupling of p-MEK to p-ERK signal and regulation of p-ERK (downregulation) and p-FADD (upregulation) may participate in the expression of some of its adverse effects (e.g. amnesia, dissociative effects).

Pentobarbital and other anesthetic agents induce opposite regulations of MAP kinases p-MEK and p-ERK, and upregulate p-FADD/FADD neuroplastic index in brain during hypnotic states in mice

Midazolam and ketamine-induced anesthesia were recently shown to induce a disruption of MEK/ERK sequential phosphorylation with parallel upregulation of p-FADD in the mouse brain. The present study was designed to assess whether other structurally diverse anesthetic agents (pentobarbital, ethanol, chloral hydrate, isoflurane) also impair brain p-MEK to p-ERK signal and increase p-FADD during the particular time course of 'sleep' in mice. Pentobarbital (50 mg/kg)-, ethanol (4000 mg/kg)-, chloral hydrate (400 mg/kg)-, and isoflurane (2% in O₂)-induced anesthesia (range: 24-60 min) were associated with unaltered or increased p-MEK1/2 (up to +155%) and decreased p-ERK1/2 (up to -60%) contents, revealing disruption of MEK to ERK activation in mouse brain cortex. These anesthetic agents also upregulated cortical p-FADD (up to +110%), but not total FADD (moderately decreased), which resulted in increased neuroplastic/survival p-FADD/FADD ratios (up to +2.8 fold). The inhibition of pentobarbital metabolism with SKF525-A (a cytochrome P450 inhibitor) augmented barbiturate anesthesia (2.6 times) and induced a greater and sustained upregulation of p-MEK with p-ERK downregulation, as well as prolonged increases of p-FADD content and p-FADD/FADD ratio (effects lasting for more than 240 min). Pentobarbital also upregulated significantly the cortical contents of other markers of neuroplasticity such as the ERK inhibitor p-PEA-15 (up to +46%), the transcription factor NF-κB (up to +27%) and the synaptic density protein PSD-95 (up to +20%) during 'sleep'. The results reveal a paradoxical stimulation of p-MEK without the concomitant (canonical) activation of p-ERK (e.g. with pentobarbital and isoflurane), for which various molecular mechanisms are discussed. The downregulation of brain p-ERK may participate in the manifestations of adverse effects displayed by most hypnotic/anesthetic agents in clinical use (e.g. amnesia).

Repeated treatment with the α2-adrenoceptor agonist UK-14304 improves cognitive performance in middle-age rats: Role of hippocampal Fas-associated death domain

The cell fate regulator Fas-associated death domain (FADD) balances cell death with non-apoptotic actions via its phosphorylated form. A recent study associated loss of cortical FADD with cognitive decline and increased risk of clinical dementia. Since the activation of cortical α_2A-adrenoceptors improved memory deficits in various animal models of working memory loss, the present study evaluated whether UK-14304, an α₂-adrenoceptor agonist known to acutely regulate brain FADD forms, would improve cognitive function in middle-aged rats. Sprague-Dawley rats were treated with UK-14304 (0.3 or 1 mg/kg) or saline (1 mL/kg) for seven days. Cognitive performance was evaluated in the eight-arm radial maze. FADD protein content was measured in the prefrontal cortex and hippocampus by Western blot analysis. The results showed that UK-14304 (1 mg/kg) improved cognitive performance (less time: -310±45 s, p=0.025 and fewer errors: -2.75±1.06, p=0.043 to complete the maze) and increased FADD selectively in the hippocampus (+35±11%, p=0.029). Interestingly, hippocampal FADD content negatively correlated with the time ( r=-0.651, p<0.01) needed to complete the maze. Thus, better cognitive scores were associated with higher FADD hippocampal content. These results support a role for α₂-adrenoceptors in ameliorating cognition and suggest FADD protein content as a possible correlate for cognitive performance.

Insights into the Roles of Midazolam in Cancer Therapy

With its high worldwide mortality and morbidity, cancer has gained increasing attention and novel anticancer drugs have become the focus for cancer research. Recently, studies have shown that most anesthetic agents can influence the activity of tumor cells. Midazolam is a γ-aminobutyric acid A (GABA_A) receptor agonist, used widely for preoperative sedation and as an adjuvant during neuraxial blockade. Some studies have indicated the potential for midazolam as a novel therapeutic cancer drug; however, the mechanism by which midazolam affects cancer cells needs to be clarified. This systematic review aims to summarize the progress in assessing the molecular mechanism of midazolam as an anticancer agent.

Disruption of brain MEK-ERK sequential phosphorylation and activation during midazolam-induced hypnosis in mice: Roles of GABAA receptor, MEK1 inactivation, and phosphatase MKP-3

Midazolam is a positive allosteric modulator at GABA_A receptor that induces a short hypnosis and neuroplasticity, in which the sequential phosphorylation of MEK1/2 and ERK1/2 was shown to play a role. This study investigated the parallel activation of p-MEK and p-ERK and regulatory mechanisms induced by midazolam through the stimulation of GABA_A receptors in the mouse brain. During the time course of midazolam (60mg/kg)-induced sleep in mice (lasting for about 2h) p-Ser217/221 MEK1/2 was increased (+146% to +258%) whereas, unexpectedly, p-Tyr204/Thr202 ERK1/2 was found decreased (-16% to -38%), revealing uncoupling of MEK to ERK signals in various brain regions. Midazolam-induced p-MEK1/2 upregulation was prevented by pretreatment (30min) with flumazenil (10mg/kg), indicating the involvement of GABA_A receptors. Also unexpectedly, midazolam-induced p-ERK1/2 downregulation was not prevented by flumazenil (10 or 30mg/kg). Notably, during midazolam-induced sleep the content of inactivated p-Thr286 MEK1, which can dampen ERK1/2 activation, was increased (+33% to +149%) through a mechanism sensitive to flumazenil (10mg/kg). Midazolam also increased MKP-3 (+13% to +73%) content and this upregulation was prevented by flumazenil (10mg/kg); an effect suggesting ERK inactivation because MKP-3 is the phosphatase selective for ERK1/2 dephosphorylation. The results indicate that during midazolam-induced sleep in mice there is an uncoupling of p-MEK (increased) to p-ERK (decreased) signals. p-ERK1/2 downregulation (not involving GABA_A receptors) is the result of increased inactivated MEK1 and phosphatase MKP-3 (both effects involving GABA_A receptors). These findings are relevant for the neurobiology and clinical use of benzodiazepines.

Regulation of cannabinoid CB2 receptor constitutive activity in vivo: repeated treatments with inverse agonists reverse the acute activation of JNK and associated apoptotic signaling in mouse brain

RATIONALE

CB₂ receptors express constitutive activity and inverse agonists regulate receptor basal activity, which might be involved in death mechanisms. This study assessed the effects of a selective CB₂ agonist (JWH133) and different CB₂ inverse agonists (AM630, JTE907, raloxifene) on death pathways in brain.

OBJECTIVES

The acute (JWH13) and the acute/chronic effects (AM630, JTE907, raloxifene) of CB₂ ligands regulating pro-apoptotic c-Jun NH₂-terminal kinase (p-JNK/JNK ratio) and associated signaling of extrinsic (Fas receptor, Fas-Associated death domain protein, FADD) and intrinsic (Bax, cytochrome c) death pathways (nuclear poly (ADP-ribose) polymerase PARP) were investigated in mouse brain.

METHODS

Mice were treated with CB₂ drugs and target protein contents were assessed by western blot analysis.

RESULTS

JWH133 reduced cortical JNK (-27-45%) whereas AM630 acutely increased JNK in cortex (+61-148%), cerebellum (+34-40%), and striatum (+33-42%). JTE907 and raloxifene also increased cortical JNK (+31%-57%). Acute AM630, but not JWH133, increased cortical FADD, Bax, cytochrome c, and PARP cleavage. Repeated treatments with the three CB₂ inverse agonists were associated with a reversal of the acute effects resulting in decreases in cortical JNK (AM630: -36%; JTE907: -25%; raloxifene: -11%). Chronic treatments also induced a reversal with down-regulation (AM630) or only tolerance (JTE907 and raloxifene) on other apoptotic markers (FADD, Bax, cytochrome c, PARP).

CONCLUSIONS

AM630 and JTE907 are CB₂ protean ligands. Thus, chronic inverse agonists abolished CB₂ constitutive activity and then the ligands behaved as agonists reducing (like JWH133) JNK activity. Acute and chronic treatments with CB₂ inverse agonists regulate in opposite directions brain death markers.

Effects of anti-depressant treatments on FADD and p-FADD protein in rat brain cortex: enhanced anti-apoptotic p-FADD/FADD ratio after chronic desipramine and fluoxetine administration

RATIONALE

Fas-associated death domain (FADD) is an adaptor of death receptors that can also induce anti-apoptotic actions through its phosphorylated form (p-FADD). Activation of monoamine receptors, indirect targets of classic anti-depressant drugs (ADs), reduced FADD and increased p-FADD and p-FADD/FADD ratio in brain.

OBJECTIVES

To ascertain whether ADs, which indirectly regulate monoamine receptors, modulate FADD protein forms to promote anti-apoptotic actions.

METHODS

The effects of selected norepinephrine transporter (NET), serotonin transporter (SERT), monoamine oxidase (MAO) inhibitors, atypical ADs, and electroconvulsive shock (ECS) or behavioral procedures (forced swim test, FST) on FADD forms and pro-survival FADD-like interleukin-1β-converting enzyme-inhibitory protein (FLIP-L) and phosphoprotein enriched in astrocytes of 15 kDa (p-PEA-15) contents were assessed in rat brain cortex by western blot analysis.

RESULTS

Acute NET (e.g., nisoxetine) but not SERT (e.g., fluoxetine) inhibitors decreased cortical FADD (up to 37 %) and increased p-FADD/FADD ratio (up to 1.9-fold). Nisoxetine effects were prevented by α2-antagonist RX-821002, suggesting the involvement of presynaptic α2-autoreceptors. Immobility time in the FST correlated with increases of pro-apoptotic FADD and decreases of anti-apoptotic p-FADD. The MAO-A/B inhibitor phenelzine decreased FADD (up to 33 %) and increased p-FADD (up to 65 %) and p-FADD/FADD (up to 2.4-fold). Other MAO inhibitors (clorgyline, Ro 41-1049, rasagiline), atypical ADs (ketamine and mirtazapine), or ECS did not modulate cortical FADD. Chronic (14 days) desipramine and fluoxetine, but not phenelzine, increased p-FADD (up to 59 %), p-FADD/FADD ratio (up to 1.8-fold), and pro-survival p-PEA-15 (up to 46 %) in rat brain cortex.

CONCLUSIONS

Multifunctional FADD protein, through an increased p-FADD/FADD ratio, could participate in the mechanisms of anti-apoptotic actions induced by ADs.