Neurotoxicity of Synthetic Cathinones / Neurotoksycznosc syntetycznych katynonów.

Synthetic cathinones are the group of the most frequently identified so-called new psychoactive substances with a strong stimulating effect and high addictive potential. It is now believed that the use of these compounds increases the risk of sporadic forms of neurodegenerative diseases. The article presents current views on the mechanisms of neurotoxicity of synthetic cathinones, including: blood-brain barrier damage, mitochondrial dysfunction, oxidative stress, neuroinflammation and hyperthermia. Further understanding of the cellular and molecular processes underlying neurotoxicity and associated clinical manifestations is essential in the development of therapeutic strategies for the prevention and treatment of neuropsychiatric disorders resulting from the intake of synthetic cathinones.

Sulodexide Increases Glutathione Synthesis and Causes Pro-Reducing Shift in Glutathione-Redox State in HUVECs Exposed to Oxygen-Glucose Deprivation: Implication for Protection of Endothelium against Ischemic Injury.

Sulodexide (SDX), a purified glycosaminoglycan mixture used to treat vascular diseases, has been reported to exert endothelial protective effects against ischemic injury. However, the mechanisms underlying these effects remain to be fully elucidated. The emerging evidence indicated that a relatively high intracellular concentration of reduced glutathione (GSH) and a maintenance of the redox environment participate in the endothelial cell survival during ischemia. Therefore, the aim of the present study was to examine the hypothesis that SDX alleviates oxygen-glucose deprivation (OGD)-induced human umbilical endothelial cells' (HUVECs) injury, which serves as the in vitro model of ischemia, by affecting the redox state of the GSH: glutathione disulfide (GSSG) pool. The cellular GSH, GSSG and total glutathione (tGSH) concentrations were measured by colorimetric method and the redox potential (ΔEh) of the GSSG/2GSH couple was calculated, using the Nernst equation. Furthermore, the levels of the glutamate-cysteine ligase catalytic subunit (GCLc) and the glutathione synthetase (GSS) proteins, a key enzyme for de novo GSH synthesis, were determined using enzyme-linked immunoassay (ELISA). We demonstrated that the SDX treatment in OGD conditions significantly elevated the intracellular GSH, enhanced the GSH:GSSG ratio, shifting the redox potential to a more pro-reducing status. Furthermore, SDX increased the levels of both GCLc and GSS. The results show that SDX protects the human endothelial cells against ischemic stress by affecting the GSH levels and cellular redox state. These changes suggest that the reduction in the ischemia-induced vascular endothelial cell injury through repressing apoptosis and oxidative stress associated with SDX treatment may be due to an increase in GSH synthesis and modulation of the GSH redox system.

Sulodexide increases mRNA expression of glutathione-related genes in human umbilical endothelial cells exposed to oxygen-glucose deprivation.

INTRODUCTION: Sulodexide (SDX), a heparinoid used to treat vascular diseases, exerts anti-ischemic properties. However, the underlying molecular mechanisms remain unclear. Induction of glutathione (GSH)-dependent genes protects against ischemia. Here, we investigated the effect of SDX on GSH-associated gene expression in human umbilical endothelial cells (HUVECs) using an in vitro ischemia model. METHODS: The transcriptional expression of GSH-related genes (GCLc, xCT, GS, GPx1 and GR) in HUVECs treated without/with SDX (0.5 LRU/ml) under oxygen-glucose deprivation (OGD) condition for 1-6 h was analyzed by real-time polymerase chain reaction. RESULTS: GCLc and xCT were strongly up-regulated by SDX in HUVECs in the first 2 h of OGD. GS and GPx1 mRNA expression levels were significantly increased during any time interval in ischemic HUVECs treated with SDX. Furthermore, incubation of HUVECs with SDX in OGD for 1-4 h resulted in enhanced expression of GR. CONCLUSIONS: Our studies provide the first evidence that SDX activates GSH-related genes in OGD-injured HUVECs.

Sulodexide up-regulates glutathione S-transferase P1 by enhancing Nrf2 expression and translocation in human umbilical vein endothelial cells injured by oxygen glucose deprivation.

INTRODUCTION: Sulodexide (SDX) is used for the treatment of many vascular disorders due to its anticoagulant, anti-inflammatory and anti-atherosclerotic properties. However, the detailed molecular mechanism of its endothelioprotective action is still not completely understood. There is increasing evidence suggesting that antioxidant enzymes play an important role in anti-ischemic properties of SDX. We postulate that up-regulation of glutathione-S-transferase P1 (GSTP1) mediated by the transcription factor Nrf2 could be associated with the antioxidant effect of SDX on vascular endothelial cells. MATERIAL AND METHODS: In the present study, we investigated whether SDX affects GSTP1 and Nrf2 in oxygen glucose deprivation (OGD) treated human umbilical vein endothelial cells (HUVECs). The cells treated with/without SDX (0.5 LRU/ml) were subjected to OGD for 1-6 h. To study the influence of SDX on the Nrf2 nucleus accumulation, the cells were incubated with 0.5 LRU/ml SDX in OGD for 1 h. RESULTS: We found that after short-term OGD (1-3 h), the drug increased the expression of both GSTP1 and Nrf2 mRNA/protein in HUVECs (p < 0.05), as determined by real-time PCR and enzyme-linked immunosorbent assay (ELISA). SDX treatment also enhanced the nuclear accumulation of Nrf2 in HUVECs after 1 h of OGD (p < 0.05). CONCLUSIONS: SDX induces a rapid onset of the antioxidant response by up-regulating the expression of GSTP1 and Nrf2 in endothelial cells subjected to in vitro simulated ischemia.

Metformin limits apoptosis in primary rat cortical astrocytes subjected to oxygen and glucose deprivation.

Metformin, a type 2 anti-diabetic drug and an activator of AMP-activated protein kinase (AMPK), has been shown to reduce infarct size and pathological changes affecting astroglia in animal models of ischemic stroke. In this study, we evaluated how metformin affects cell viability, apoptosis and determined the role of AMPK, as well as JNK p46/p54 and p38 kinases, in the observed phenomena in the culture of primary rat cortical astrocytes subjected to 12 h of oxygen and glucose deprivation (OGD). Metformin improved cell viability, reduced the fraction of apoptotic nuclei, and inhibited the activation of the executive caspase-3. Decreased activation of JNK p54 and p38 was associated with increased Bcl-XL expression and decreased mitochondrial leakage of cytochrome c. However, only cell viability and partially the fraction of apoptotic nuclei varied concomitantly with changes in AMPK activity, suggesting that AMPK is critical for metformin-mediated effects and regulates programmed cell death in a caspase-independent manner. Experiments with the inhibitors of JNK and p38 supports the role of these kinases in the drug-related inhibition of mitochondrial and extrinsic pathway of apoptosis.

Lysosomal dysfunction in neurodegenerative diseases.

Dane literaturowe z ostatnich lat jednoznacznie wskazuja na udzial lizosomów w programowanej smierci komórki. Dysfunkcje lizosomów uposledzaja fuzje autofagosomów z lizosomami, co prowadzi do wakuolizacji cytoplazmy. Obecnosc wakuoli autofagalnych obladowanych uszkodzonymi organellami i nieprawidlowymi bialkami jest cecha charakterystyczna wielu chorób neurodegeneracyjnych. Agregacja niezdegradowanego materialu zaburza homeostaze komórki powodujac smierc neuronu w wyniku apoptozy i/lub nekrozy. Ponadto indukowany kalpainami lub spowodowany mutacjami rozpad blony lizosomu uwalnia katepsyny, które indukuja szlak smierci komórki. W artykule przedstawiono mechanizm smierci komórki nerwowej, laczacy zaburzenie szlaku autofagalno-lizosomalnego z dysfunkcjami lizosomów, zwany lizosomalnym szlakiem smierci neuronu.

Time-Dependent Changes in Apoptosis Upon Autophagy Inhibition in Astrocytes Exposed to Oxygen and Glucose Deprivation.

Recent studies have implicated the role of autophagy in brain ischemia pathophysiology. However, it remains unclear whether autophagy activation is protective or detrimental to astrocytes undergoing ischemic stress. This study evaluated the influence of ischemia-induced autophagy on cell death and the course of intrinsic and extrinsic apoptosis in primary cultures of rat cortical astrocytes exposed to combined oxygen-glucose deprivation (OGD). The role of autophagy was assessed by pharmacological inhibition with 3-methyladenine (3-MA). Cell viability was evaluated by measuring LDH release and through the use of the alamarBlue Assay. Apoptosis and necrosis were determined by fluorescence microscopy after Hoechst 33,342 and propidium iodide staining, respectively. The levels of apoptosis-related proteins were analyzed by immunoblotting. The downregulation of autophagy during OGD resulted in decreased cell viability and time-dependent changes in levels of apoptosis and necrosis. After short-term OGD (1, 4 h), cells treated with 3-MA showed higher level of cleaved caspase 3 compared with control cells. This result was consistent with an evaluation of apoptotic cell number by fluorescence microscopy. However, after prolonged exposure to OGD (8, 24 h), the number of apoptotic astrocytes (microscopically evaluated) did not differ or was even lower (as marked by caspase 3) in the presence of the autophagy inhibitor in comparison to the control. A higher level of necrosis was observed in 3-MA-treated cells compared to non-treated cells after 24 h OGD. The downregulation of autophagy caused time-dependent changes in both extrinsic (cleaved caspase 8, TNFα) and intrinsic (cleaved caspase 9) apoptotic pathways. Our results strongly indicate that the activation of autophagy in astrocytes undergoing ischemic stress is an adaptive mechanism, which allows for longer cell survival by delaying the initiation of apoptosis and necrosis.

Superoxide dismutase 1 and glutathione peroxidase 1 are involved in the protective effect of sulodexide on vascular endothelial cells exposed to oxygen-glucose deprivation.

Sulodexide (SDX) is widely used in the treatment of both arterial and venous thrombotic disorders. In addition to its recognized antithrombotic action, SDX has endothelial protective potential, which is independent of the coagulation/fibrinolysis system. However, the detailed molecular mechanisms of the endothelioprotective action of the drug are still unresolved. The aim of the present study was to determine whether treatment with SDX at concentrations of 0.125-0.5 lipase releasing unit (LRU)/ml have on the expression and activity of antioxidant enzymes in ischemic endothelial cells and how these effects might be related to the antiapoptotic properties of SDX. In the present study, human umbilical vein endothelial cells (HUVECs) were subjected to ischemia-simulating conditions (combined oxygen and glucose deprivation, OGD) for 6h to determine the protective effects of SDX. SDX (0.25 and 0.5LRU/ml) in OGD significantly increased the cell viability and prevented mitochondrial depolarization in the HUVECs. Moreover, SDX protected the HUVECs against OGD-induced apoptosis. At concentrations of 0.25 and 0.5LRU/ml, the drug increased both superoxide dismutase 1 (SOD1) and glutathione peroxidase 1 (GPx1) mRNA/protein expression together with a significant attenuation of oxidative stress in ischemic HUVECs. Our findings also demonstrate that an increase in both SOD and GPx activity is involved in the protective effect of SDX on ischemic endothelial cells. Altogether, these results suggest that SDX has a positive effect on ischemia-induced endothelial damage because of its antioxidant and antiapoptotic properties.

[Astrocytes in ischemic stroke - a potential target for neuroprotective strategies]. / Astrocyty w udarze niedokrwiennym mózgu ­ potencjalny cel strategii neuroprotekcyjnych.

Ischemic stroke is one of the leading causes of adult death and disability worldwide. Present applied therapeutic strategies do not give satisfactory results. It is often emphasized that pharmacological actions aimed at reducing the area of ischemic brain injury should protect astrocytes forming together with neurons and the endothelium neurovascular unit. Astrocytes contribute importantly to proper neuronal function during both physiological and pathological conditions. In ischemic stroke, astrocytes are involved in regulation of water and ion homeostasis, cerebral blood flow, maintenance of the blood-brain barrier, and control of the extracellular level of glutamate, as well as being a source of neuroprotectants. On the other hand, astrocytes may also contribute to enlarged ischemic area due to their participation in inflammatory processes and production of potential neurotoxic substances. Herein we review experimental and clinical data concerning adaptive and pathological roles of astrocytes during both early and late phases of ischemia. Especially, we emphasize specific features of astrocytes that might become a potential target of therapeutic strategies for ischemic stroke.

The latest achievements in the pharmacotherapy of gambling disorder.

Gambling disorder (GD) is becoming increasingly prevalent both among adults and adolescents. Unfortunately, this disorder is largely underestimated, while it can still lead to serious social and personal consequences, including criminal behavior or suicide attempts. In the past, the only means of treating gambling were psychobehavioral therapies. Nowadays, this disorder could also respond to many drugs from different classes such as opioid antagonists, serotonin selective reuptake inhibitors, mood stabilizers, atypical antipsychotics or glutamatergic agents. This review presents current pharmacological strategies and the results of clinical trials evaluating the efficacy of pharmacotherapy for GD. It also discusses the importance of distinguishing different pathological gambler subtypes such as impulsive, obsessive-compulsive and addictive subtypes as this may have serious pharmacological implications.

[Dysregulation of the mTOR signaling pathway in the pathogenesis of autism spectrum disorders]. / Dysregulacja szlaku sygnalowego mTOR w patogenezie zaburzen ze spektrum autystycznego.

Mammalian target of rapamycin (mTor) plays multiple role in central nervous system and is involved in regulation of cell viability, differentiation, transcription, translation, protein degradation, actin cytoskeletal organization and autophagy. Recent experimental and clinical studies reveal that disturbances of mTOR signaling are involved in the pathogenesis of autism spectrum disorders (ASD). This article reviews current data on the alteration in the mTOR transduction cascade, which may contribute to common neurobehavioral disorders typical for ASD. Moreover, the results of the latest experimental studies on the potential of mTOR inhibitors for the treatment of ASD are reviewed.

AMP-activated protein kinase is involved in induction of protective autophagy in astrocytes exposed to oxygen-glucose deprivation.

AMP-activated kinase (AMPK) acts as the intracellular ATP depletion sensor, which detects and limits increases in the AMP/ATP ratio. AMPK may be significantly activated under stress conditions that deplete cellular ATP levels such as ischemia/hypoxia or glucose deprivation. Recent studies strongly suggest that AMPK participates in autophagy regulation, but it is not known whether AMPK activated by ischemia regulates autophagy in astrocytes and the consequence of autophagy activation in ischemic astrocytes are unclear. We have investigated the contribution of AMPK to autophagy activation in rat primary astrocyte cultures subjected to ischemia-simulating conditions (combined oxygen glucose deprivation, OGD) and its potential effects on astrocyte damage induced by OGD (1-12 h). The evidence supports the conclusion that AMPK activation at early stages of OGD is involved in induction of protective autophagy in astrocytes. Inhibition of AMPK, either by siAMPKα1 or by compound C, significantly attenuated the expression of autophagy-related proteins and decrease of astrocyte viability following OGD. The findings provide additional data about the role of AMPK in ischemic astrocytes and downstream responses that may be involved in OGD-induced protective autophagy.

[Metformin as a key to alternative activation of microglia?]. / Metformina kluczem do alternatywnej aktywacji mikrogleju?

The results of recent studies suggest that metformin, in addition to its antihyperglycemic efficacy, may also attenuate neuroinflammation and directly act on the central nervous system. However, the molecular mechanisms by which metformin exerts its anti-inflammatory effects in the brain remain largely unknown. Adenosine-monophosphate-activated protein kinase (AMPK) activation is the most well-known mechanism of metformin action. However, some of the biological responses to metformin (e.g. the release of cytokines and the expression of arginase I or PGC-1α) are not limited to AMPK activation but also are mediated by AMPK-independent mechanisms. This article reviews current evidence supporting the hypothesis that the shift of microglia toward alternative activation may underlie the beneficial effects of metformin observed in animal models of neurological disorders.