Midazolam provides cytoprotective effect during corticosterone-induced damages in rat astrocytes by stimulating steroidogenesis

Anticancer Effects of Midazolam on Lung and Breast Cancers by Inhibiting Cell Proliferation and Epithelial-Mesenchymal Transition

Despite improvements in cancer treatments resulting in higher survival rates, the proliferation and metastasis of tumors still raise new questions in cancer therapy. Therefore, new drugs and strategies are still needed. Midazolam (MDZ) is a common sedative drug acting through the γ-aminobutyric acid receptor in the central nervous system and also binds to the peripheral benzodiazepine receptor (PBR) in peripheral tissues. Previous studies have shown that MDZ inhibits cancer cell proliferation but increases cancer cell apoptosis through different mechanisms. In this study, we investigated the possible anticancer mechanisms of MDZ on different cancer cell types. MDZ inhibited transforming growth factor β (TGF-β)-induced cancer cell proliferation of both A549 and MCF-7 cells. MDZ also inhibited TGF-β-induced cell migration, invasion, epithelial-mesenchymal-transition, and Smad phosphorylation in both cancer cell lines. Inhibition of PBR by PK11195 rescued the MDZ-inhibited cell proliferation, suggesting that MDZ worked through PBR to inhibit TGF-β pathway. Furthermore, MDZ inhibited proliferation, migration, invasion and levels of mesenchymal proteins in MDA-MD-231 triple-negative breast cancer cells. Together, MDZ inhibits cancer cell proliferation both in epithelial and mesenchymal types and EMT, indicating an important role for MDZ as a candidate to treat lung and breast cancers.

Effects of Long-Term Endogenous Corticosteroid Exposure on Brain Volume and Glial Cells in the AdKO Mouse

Chronic exposure to high circulating levels of glucocorticoids has detrimental effects on health, including metabolic abnormalities, as exemplified in Cushing’s syndrome (CS). Magnetic resonance imaging (MRI) studies have found volumetric changes in gray and white matter of the brain in CS patients during the course of active disease, but also in remission. In order to explore this further, we performed MRI-based brain volumetric analyses in the AdKO mouse model for CS, which presents its key traits. AdKO mice had reduced relative volumes in several brain regions, including the corpus callosum and cortical areas. The medial amygdala, bed nucleus of the stria terminalis, and hypothalamus were increased in relative volume. Furthermore, we found a lower immunoreactivity of myelin basic protein (MBP, an oligodendrocyte marker) in several brain regions but a paradoxically increased MBP signal in the male cingulate cortex. We also observed a decrease in the expression of glial fibrillary acidic protein (GFAP, a marker for reactive astrocytes) and ionized calcium-binding adapter molecule 1 (IBA1, a marker for activated microglia) in the cingulate regions of the anterior corpus callosum and the hippocampus. We conclude that long-term hypercorticosteronemia induced brain region-specific changes that might include aberrant myelination and a degree of white matter damage, as both repair (GFAP) and immune (IBA1) responses are decreased. These findings suggest a cause for the changes observed in the brains of human patients and serve as a background for further exploration of their subcellular and molecular mechanisms.

Methylglyoxal disturbs DNA repair and glyoxalase I system in Saccharomyces cerevisiae

Methylglyoxal (MG) is a highly reactive aldehyde able to form covalent adducts with proteins and nucleic acids, disrupting cellular functions. In this study, we performed a screening of Saccharomyces cerevisiae (S. cerevisiae) strains to find out which genes of cells are responsive to MG, emphasizing genes against oxidative stress and DNA repair. Yeast strains were grown in the YPD-Galactose medium containing MG (0.5 to 12 mM). The tolerance to MG was evaluated by determining cellular growth and cell viability. The toxicity of MG was more pronounced in the strains with deletion in genes engaged with DNA repair checkpoint proteins, namely Rad23 and Rad50. MG also impaired the growth and viability of S. cerevisiae mutant strains Glo1 and Gsh1, both components of the glyoxalase I system. Differently, the strains with deletion in genes encoding for antioxidant enzymes were apparently resistant to MG. In summary, our data indicate that DNA repair and MG detoxification pathways are keys in the control of MG toxicity in S. cerevisiae.

A Comparison of Hematological, Immunological, and Stress Responses to Capture and Transport in Wild White Rhinoceros Bulls (Ceratotherium simum simum) Supplemented With Azaperone or Midazolam

Capture and transport are essential procedures for the management and conservation of southern white rhinoceroses (Ceratotherium simum simum), but are associated with stress-induced morbidity and mortality. To improve conservation efforts, it is crucial to understand the pathophysiology of rhinoceros stress responses and investigate drug combinations that could reduce these responses. In this study we measured rhinoceros stress responses to capture and transport by quantifying hematological and immunological changes together with adrenal hormone concentrations. We investigated whether the potent anxiolytic drug midazolam was able to mitigate these responses compared to azaperone, which is more commonly used during rhinoceros transport. Twenty three wild white rhinoceros bulls were transported for 6 h (280 km) within the Kruger National Park for reasons unrelated to this study. Rhinoceroses were immobilized with either etorphine-azaperone (group A, n = 11) or etorphine-midazolam (group M, n = 12) intramuscularly by darting from a helicopter. Azaperone (group A) or midazolam (group M) were re-administered intramuscularly every 2 h during transport. Serial blood samples were collected at capture (TC), the start of transport (T0) and after 6 h of transport (T6). Changes in hematological and immunological variables over time and between groups were compared using general mixed models. Increases in plasma epinephrine and serum cortisol concentrations indicated that rhinoceroses mounted a stress response to capture and transport. Packed cell volume decreased from TC to T6 indicating that stress hemoconcentration occurred at TC. Neutrophils progressively increased and lymphocytes and eosinophils progressively decreased from T0 to T6, resulting in an increase in neutrophil to lymphocyte ratio; a characteristic leukocyte response to circulating glucocorticoids. A reduction in serum iron concentrations may suggest the mounting of an acute phase response. Rhinoceroses experienced a decrease in unsaturated fatty acids and an increase in lipid peroxidation products at capture and toward the end of transport indicating oxidative stress. Midazolam, at the dose used in this study, was not able to mitigate adrenal responses to stress and appeared to directly influence leukocyte responses.

Cytoprotective effects of paeoniflorin are associated with translocator protein 18 kDa

Paeoniflorin (PF) is one of the important active components in peony that are known to produce the neuroprotective effects. However, the involved cytoprotective factors on brain astrocytes are remain unclear. Translocator protein 18 kDa (TSPO) and its downstream neurosteroids biosynthesis play a significant role in cytoprotection. Based on these, the role of TSPO and neurosteroids biosynthesis in the cytoprotective effects of PF is evaluated. The astrocyte cells were cultured and AC-5216 (TSPO ligand) was selected as the positive control drug. The cytoprotective effects of PF and the levels of neurosteroids were quantified by water-soluble tetrazolium assay and enzyme linked immunosorbent assay, respectively. The cytoprotective activities of PF were relevant to neurosteroids (e.g. progsterone and allopregnanolone) biosynthesis, while these effects were totally blocked by PK11195, trilostane and finasteride, respectively. In summary, the cytoprotective effects of PF maybe mediated by TSPO and neurosteroids biosynthesis. The findings may provide the new insights into the cytoprotective effects of PF.

The anxiolytic-like effects of estazolam on a PTSD animal model

Post-traumatic stress disorder (PTSD) is a serious psychiatric disorder. Estazolam has been shown to produce anxiolytic-, hypnotic-, amnestic-, and sedative-like effects. However, few studies are concerned about its anti-PTSD-like effects. The anti-PTSD-like effects of estazolam were evaluated by single prolonged stress animal model. After exposure to single prolonged stress, rats (Sprague-Dawley, male, 8 weeks) were administered by estazolam (0.5, 1 and 2 mg/kg, i.p.) from day 2 to 13 once daily. The behavioral assessments were performed during treatment with drugs. After the behavioral evaluation, the role of allopregnanolone in the anti-PTSD-like effects of estazolam was also evaluated via astrocyte cells and brain tissues (e.g. prefrontal cortex, hippocampus, and amygdala). The PTSD-like behavioral deficits were significantly blocked by estazolam (1 and 2 mg/kg, i.p.) without affecting locomotor activity. Consistently, the levels on allopregnanolone were increased by estazolam (1 and 2 mg/kg, i.p.) in prefrontal cortex, hippocampus, and amygdala. The levels of allopregnanolone were increased by sertraline (1 µmoL/L) and estazolam (4 µmoL/L), while the effects were antagonized by trilostane (1 µmoL/L) and finasteride (1 µmoL/L) in astrocyte cells, respectively. Collectively, the anxiety-like behavior deficits were ameliorated by estazolam in the single prolonged stress animal model that was associated with biosynthesis of allopregnanolone.

The cardioprotective effect of dihydromyricetin prevents ischemia-reperfusion-induced apoptosis in vivo and in vitro via the PI3K/Akt and HIF-1α signaling pathways

Reperfusion therapy is widely used to treat acute myocardial infarction (AMI). However, further injury to the heart induced by rapidly initiating reperfusion is often encountered in clinical practice. A lack of pharmacological strategies in clinics limits the prognosis of patients with myocardial ischemia-reperfusion injury (MIRI). Dihydromyricetin (DMY) is one of the most abundant components in vine tea, commonly known as the tender stems and leaves of Ampelopsis grossedentata. The aim of this study was to evaluate the cardioprotection of DMY against myocardial ischemia-reperfusion (I/R) injury and to further investigate the underlying mechanism. An I/R injury was induced by left anterior descending coronary artery occlusion in adult male rats in vivo and a hypoxia-reoxygenation (H/R) injury in H9c2 cardiomyocytes in vitro. We found that DMY pretreatment provided significant protection against I/R-induced injury, including enhanced antioxidant capacity and inhibited apoptosis in vivo and in vitro. This effect correlated with the activation of the PI3K/Akt and HIF-1α signaling pathways. Conversely, blocking Akt activation with the PI3K inhibitor LY294002 effectively suppressed the protective effects of DMY against I/R-induced injury. In addition, the PI3K inhibitor partially blocked the effects of DMY on the upregulation of Bcl-2, Bcl-xl, procaspase-3, -8, and -9 protein expression and the downregulation of HIF-1α, Bnip3, Bax, Cyt-c, cleaved caspase-3, -8, and -9 protein expression. Collectively, these results showed that DMY decreased the apoptosis and necrosis by I/R treatment, and PI3K/Akt and HIF-1α plays a crucial role in protection during this process. These observations indicate that DMY has the potential to exert cardioprotective effects against I/R injury and the results might be important for the clinical efficacy of AMI treatment.

PPARβ/δ activation protects against corticosterone-induced ER stress in astrocytes by inhibiting the CpG hypermethylation of microRNA-181a

Increasing evidence indicates that peroxisome proliferator-activated receptors (PPARs) play neuroprotective roles in various neurodegenerative disease models in vivo and in vitro. However, the underlying mechanisms remain unclear. Astrocyte proliferation is a key process in neural development and plays significant roles in the regeneration of neural tissue after a penetrating injury. Corticosterone can significantly reduce the expression of glial fibrillary acid protein (GFAP) in cultured rat hippocampal astrocytes in vitro, and induce astrocytic dysfunction. Our research found that corticosterone treatment resulted in astrocyte damage and reduced the expression of PPARβ/δ. GW0742, a selective and high-affinity PPARβ/δ agonist, attenuated the corticosterone-induced astrocyte damage, but also significantly reversed the increase in the expression of GRP78 and CHOP, the two predominant proteins in endoplasmic reticulum (ER) stress. Moreover, GW0742 decreased the levels of caspase-12 and cleaved caspase-3, thereby protecting astrocytes against corticosterone-induced astrocyte apoptosis. We then confirmed that GRP78 was a target gene of microRNA-181a and found that PPARβ/δ activation increased microRNA-181a levels. Finally, we demonstrated that PPARβ/δ activation by GW0742 noticeably inhibited the activities and expression of DNA methyltransferases, and reduced the corticosterone-induced CpG island hypermethylation of microRNA-181a1 in astrocytes. Therefore, the present study is the first to reveal that PPARβ/δ activation suppresses CpG island hypermethylation-associated silencing of microRNA-181a and thereby protects against ER stress-induced damage in astrocytes. Our findings suggest that PPARβ/δ activation in astrocytes might be a promising target for regulating ER stress-induced astrocytic injury.

Translocator protein mediates the anxiolytic and antidepressant effects of midazolam

The translocator protein (18 kDa) (TSPO) plays an important role in stress-related disorders, such as anxiety, depression and post-traumatic stress disorder (PTSD), caused by neurosteroids (e.g. allopregnanolone). The present study sought to evaluate the significance of TSPO in anxiolytic and antidepressant effects induced by midazolam. The animals were administrated midazolam (0.25, 0.5 and 1 mg/kg, i.p.) and subjected to behavioral tests, including Vogel-type conflict test, elevated plus-maze test, forced swimming test. Midazolam produced anxiolytic- and antidepressant-like effects Vogel-type conflict test (1 mg/kg, i.p.), elevated plus-maze test (0.5 and 1 mg/kg, i.p.), and forced swimming test (0.5 and 1 mg/kg, i.p.). These effects of Midazolam were totally blocked by the TSPO antagonist PK11195 (3 mg/kg, i.p.). To evaluate the role of allopregnanolone in the anxiolytic- and antidepressant-like effects of midazolam, the animals were decapitated at the end of the behavioral tests. The allopregnanolone levels of the prefrontal cortex and hippocampus were measured by enzyme-linked immunosorbent assay (ELISA). The allopregnanolone level of the prefrontal cortex and hippocampus was increased by midazolam (0.5, 1 mg/kg, i.p.) and the increase was reversed by PK11195 (3 mg/kg, i.p.). Overall, the results indicated that the anxiolytic- and antidepressant-like effects of midazolam were mediated by TSPO, via stimulation of allopregnanolone biosynthesis.

Pretreatment but not subsequent coincubation with midazolam reduces the cytotoxicity of temozolomide in neuroblastoma cells

Background

Temozolomide (TMZ) induces a G2/M cell cycle arrest and is used for treatment of paediatric tumours, especially neuroblastomas. Patients treated with TMZ frequently receive midazolam for sedation prior to surgery and other interventions. Previous studies suggested both cytoprotective and apoptosis-inducing properties of midazolam. Therefore, the impact of midazolam on TMZ-induced cytotoxicity was investigated in vitro.

Methods

Human neuroblastoma cells were incubated with midazolam alone, as a pretreatment prior to incubation with TMZ or a coincubation of both. Cell viability and proliferation was analysed (XTT and BrdU assay) after 24 h and flowcytometric cell cycle analysis was performed after 24 and 48 h.

Results

Midazolam alone increased cell viability at lower concentrations (2, 4, 8, 16 μM), whereas higher concentrations (128, 256, 512 μM) reduced cell viability. Pretreatment with midazolam 6 h prior to TMZ incubation reduced cytotoxic effects (IC₂₅ 1005 ± 197 μM; IC₅₀ 1676 ± 557 μM; P < 0.05) compared to incubation with TMZ alone (IC₂₅ 449 ± 304 μM; IC₅₀ 925 ± 196 μM) and reduced the antiproliferative effect of TMZ (1000 μM) by 43.9 % (P < 0.05). In contrast, cytotoxic effects of TMZ were increased (IC₇₅ 1175 ± 221 μM vs. 2764 ± 307 μM; P < 0.05) when midazolam pretreatment was followed by coincubation of midazolam and TMZ. Cell cycle analysis revealed increased fractions of cells in G2/M phase after TMZ treatment (100 μM; 48 h), irrespective of midazolam pretreatment.

Conclusion

Midazolam causes a hormetic dose–response relationship in human neuroblastoma cells. Pretreatment with midazolam reduces the cytotoxic and antiproliferative effects of TMZ without interfering with G2/M cell cycle arrest. In contrast, subsequent midazolam coincubation increases overall cytotoxicity.

Midazolam inhibits the hypoxia-induced up-regulation of erythropoietin in the central nervous system

Erythropoietin (EPO), a regulator of red blood cell production, is endogenously expressed in the central nervous system. It is mainly produced by astrocytes under hypoxic conditions and has proven to have neuroprotective and neurotrophic effects. In the present study, we investigated the effect of midazolam on EPO expression in primary cultured astrocytes and the mouse brain. Midazolam was administered to 6-week-old BALB/c male mice under hypoxic conditions and pregnant C57BL/6N mice under normoxic conditions. Primary cultured astrocytes were also treated with midazolam under hypoxic conditions. The expression of EPO mRNA in mice brains and cultured astrocytes was studied. In addition, the expression of hypoxia-inducible factor (HIF), known as the main regulator of EPO, was evaluated. Midazolam significantly reduced the hypoxia-induced up-regulation of EPO in BALB/c mice brains and primary cultured astrocytes and suppressed EPO expression in the fetal brain. Midazolam did not affect the total amount of HIF proteins but significantly inhibited the nuclear expression of HIF-1α and HIF-2α proteins. These results demonstrated the suppressive effects of midazolam on the hypoxia-induced up-regulation of EPO both in vivo and in vitro.

Dihydromyricetin ameliorates the oxidative stress response induced by methylglyoxal via the AMPK/GLUT4 signaling pathway in PC12 cells

Dihydromyricetin (DMY), the major bioactive flavonoid ingredient extracted from the leaves of Ampelopsis grossedentata (Hand.-Mazz) W.T. Wang, displays multiple pharmacological activities, including oxidation resistance, antitumor properties and free radical scavenging capacities. However, the role of DMY in methylglyoxal (MG)-induced diabetes-associated cognitive decline and its underlying molecular mechanisms are unclear. The aim of the present study was to evaluate the effects of DMY on oxidative stress and glucose transport activity in a MG-induced PC12 cell line and to explore the related mechanisms. The effects of DMY on cell survival and apoptosis were examined, and the dysregulation of intracellular Ca(2+) was determined. Oxidative stress was evaluated by monitoring ROS production and the glutathione to glutathione disulfide ratio. The effects of DMY on glucose metabolism were investigated using a fluorescently labeled deoxyglucose analog and by measuring ATP and lactate production. Western blot analysis was performed to examine the protein levels of glyoxalase I (Glo-1), glucose transporter 4 (GLUT4), AMP-activated protein kinase (AMPKα) and phosphorylated AMPKα (p-AMPKα). The results revealed that DMY suppressed cellular oxidative stress in PC12 cells and balanced glucose metabolism. Additionally, DMY reduced GLUT4 translocation dysfunction and increased Glo-1 and p-AMPKα expression. We found that DMY protected PC12 cells against MG-induced apoptosis and glycometabolic disorders, at least in part by restraining the hyperactivation of p-AMPK activity and normalizing the translocation of GLUT4 from the intracellular compartment, resulting in a balance in glucose uptake. This result indicates that DMY may serve as a novel and effective candidate agent to treat diabetic encephalopathy by reducing the toxicity of MG.

Systemic inflammation is associated with a reduction in Synaptopodin expression in the mouse hippocampus

Systemic inflammation is known to affect memory function through the activation of immune cells and the release of inflammatory cytokines. However, the neuronal targets by which inflammatory signaling pathways affect synaptic plasticity remain not well understood. Here, we addressed the question of whether systemic lipopolysaccharide (LPS)-induced inflammation influences the expression of Synaptopodin (SP). SP is an actin-binding protein, which is considered to control the ability of neurons to express synaptic plasticity by regulating the actin-cytoskeleton and/or intracellular Ca(2+) stores. This makes SP an interesting target molecule in the context of inflammation-induced alterations in synaptic plasticity. Using quantitative PCR (qPCR)-analysis and immunohistochemistry we here demonstrate that intraperitoneal LPS-injection in two-month old male Balb/c mice leads to a reduction in hippocampal SP-levels (area CA1; 24h after injection). These changes are accompanied by a defect in the ability to induce long-term potentiation (LTP) of Schaffer collateral-CA1 synapses, similar to what is observed in SP-deficient mice. We therefore propose that systemic inflammation could exert its effects on neural plasticity, at least in part, through the down-regulation of SP in vivo.

Cerebrospinal fluid cortisol and progesterone profiles and outcomes prognostication after severe traumatic brain injury

Despite significant advances in the management of head trauma, there remains a lack of pharmacological treatment options for traumatic brain injury (TBI). While progesterone clinical trials have shown promise, corticosteroid trials have failed. The purpose of this study was to (1) characterize endogenous cerebrospinal fluid (CSF) progesterone and cortisol levels after TBI, (2) determine relationships between CSF and serum profiles, and (3) assess the utility of these hormones as predictors of long-term outcomes. We evaluated 130 adults with severe TBI. Serum samples (n=538) and CSF samples (n=746) were collected for 6 days post-injury, analyzed for cortisol and progesterone, and compared with healthy controls (n=13). Hormone data were linked with clinical data, including Glasgow Outcome Scale (GOS) scores at 6 and 12 months. Group based trajectory (TRAJ) analysis was used to develop temporal hormone profiles delineating distinct subpopulations. Compared with controls, CSF cortisol levels were significantly and persistently elevated during the first week after TBI, and high CSF cortisol levels were associated with poor outcome. As a precursor to cortisol, progesterone mediated these effects. Serum and CSF levels for both cortisol and progesterone were strongly correlated after TBI relative to controls, possibly because of blood-brain barrier disruption. Also, differentially impaired hormone transport and metabolism mechanisms after TBI, potential de novo synthesis of steroids within the brain, and the complex interplay of cortisol and pro-inflammatory cytokines may explain these acute hormone profiles and, when taken together, may help shed light on why corticosteroid trials have previously failed and why progesterone treatment after TBI may be beneficial.