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OBJECTIVE Glioma stem cells (GSCs) are responsible for tumor initiation, therapeutic resistance, and recurrence. CD146 is mainly expressed in dividing GSCs and regulates cell cycle progression. However, the evaluation of the efficacy of targeted therapy against CD146 in vivo remains to be investigated. In this study, the authors aimed to develop gene therapy targeting GSCs using chitosan oligosaccharide lactate (COL) nanoparticles (NPs) conjugated with folic acid–polyethylene glycol (FA-PEG-COL NPs) for in vitro and in vivo delivery of CD146 small-interfering RNA (siCD146) and to determine the effect of CD146 knockdown on tumor growth. METHODS To examine the uptake of NPs by tumor cells, immunofluorescence staining, flow cytometry, and in vivo imaging were performed. The knockdown effect of siCD146 was measured by western blot and water-soluble tetrazolium salt–8 assay in mouse glioma cells. The efficacy of siRNA therapy–targeted GSCs was evaluated by monitoring tumor growth through in vivo imaging and histological analysis. RESULTS In vivo accumulation of the FA-PEG-COL NPs in subcutaneous and intracranial gliomas following NP administration via a mouse tail vein was observed. Additionally, in vitro delivery of siCD146 ionically cross-linked NPs, reduced CD146 levels, and suppressed growth in the glioma tumor sphere. Evaluation of the in vivo therapeutic effects of siCD146–cross-linked NPs in a mouse glioma model revealed significant suppression of intracranial tumor growth, with complete removal of the tumor observed in some mice on histological examination. Furthermore, delivery of siCD146 significantly reduced the Ki-67 index in residual tumor tissues relative to that in control mice. CONCLUSIONS CD146 is a potential therapeutic target, and folic acid–conjugated NPs delivering siRNA may facilitate gene therapy in malignant gliomas.

Ischemic stroke is one of the most prevalent brain disorders and the major cause of long-term disability. In particularly, hippocampal injury after ischemia-reperfusion is a serious problem as it contributes to vascular dementia. Many researches have revealed that ischemia-reperfusion causes increase in reactive oxygen species production and disruption of neuronal Zn2+ homeostasis in the hippocampus, which induces hippocampal neuron death. Glutathione (GSH) is present in all mammalian cells and plays a crucial role in neuronal cell defense against oxidative stress. On the other hand, thiol group of GSH chemically chelates Zn2+ and functions as a regulator of neuronal Zn2+ homeostasis. These evidences suggest that neuronal GSH levels could be an important factor affecting neuronal surviving. The synthesis of GSH is largely influenced by intracellular cysteine availability. In neurons, excitatory amino acid carrier type 1 (EAAC1) acts as a cysteine transporter and provides cysteine substrate for GSH synthesis. Recently, several animal studies have revealed that promotion of neuronal GSH synthesis through EAAC1 reduces ischemia-induced hippocampal neuron death. This review aims to describe neuroprotective role of GSH against hippocampal injury following ischemia-reperfusion, focusing on EAAC1.

AIM Brain nitric oxide (NO) have been reported in regulation of the sympatho-adrenomedullary system, which can affect voiding and storage functions. Therefore, we investigated effects of intracerebroventricularly (icv) administered 3-(4-morpholinyl)sydnonimine, hydrochloride (SIN-1) (NO donor) on the micturition reflex, focusing on their dependence on the sympatho-adrenomedullary system and on brain N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors in urethane-anesthetized (0.8 g/kg, ip) male Wistar rats. METHODS Plasma noradrenaline and adrenaline were measured just before and 5 minutes after SIN-1 administration. Evaluation of urodynamic parameters was started 1 hour before SIN-1 administration or intracerebroventricular pretreatment with other drugs. RESULTS SIN-1 (100 and 250 µg/animal) elevated plasma adrenaline and reduced intercontraction interval ([ICI] values; 110.5% [SIN-1, 0 µg] and 54.9% [SIN-1, 250 µg] during 15 minutes after SIN-1 administration [P

Corticotropin-releasing factor (CRF), a representative stress-related neuropeptide, in the central nervous system reportedly both facilitates and suppresses the micturition, therefore, roles of central CRF in regulation of the micturition are still controversial. In this study, we investigated (1) effects of intracerebroventricularly (icv)-administered CRF on the micturition, and (2) brain CRF receptor subtypes (CRFR1/CRFR2) and glutamatergic receptors (NMDA/AMPA subtypes) involved in the CRF-induced effects in male Wistar rats under urethane anesthesia. Intercontraction intervals (ICI), and maximal voiding pressure (MVP), were evaluated by continuous cystometry 45 min before CRF administration or intracerebroventricular pretreatment with other drugs as follows and 3 h after CRF administration. Single-voided volume (Vv), post-voiding residual volume (Rv), bladder capacity (BC), and voiding efficiency (VE) were evaluated by single cystometry 60 min before CRF administration and 60-120 min after the administration. Icv-administered CRF reduced ICI, Vv, and BC without changing MVP, Rv, or VE. The CRF-induced ICI reduction was attenuated by icv-pretreated CP154526 (CRFR1 antagonist), MK-801 (NMDA receptor antagonist), and DNQX (AMPA receptor antagonist), but not by K41498 (CRFR2 antagonist). These results indicate that stimulation of brain CRFR1 can be involved in facilitation of the rat micturition via brain NMDA/AMPA receptors.

INTRODUCTION AND OBJECTIVE:Although aging or severe bladder ischemia could be involved in progression of detrusor underactivity (DU), the pathophysiological mechanism of DU is not well clarified. H...

Brain nicotinic acetylcholine receptors (nAChRs) reportedly suppress the micturition, but the mechanisms responsible for this suppression remain unclear. We previously reported that intracerebroventricularly administered (±)-epibatidine (non-selective nAChR agonist) activated the sympatho-adrenomedullary system, which can affect the micturition. Therefore, we investigated (1) whether intracerebroventricularly administered (±)-epibatidine-induced effects on the micturition were dependent on the sympatho-adrenomedullary system, and (2) brain nAChR subtypes involved in the (±)-epibatidine-induced effects in urethane-anesthetized male Wistar rats. Plasma noradrenaline and adrenaline (catecholamines) were measured just before and 5 min after (±)-epibatidine administration. Evaluation of urodynamic parameters, intercontraction intervals (ICI) and maximal voiding pressure (MVP) by cystometry was started 1 h before (±)-epibatidine administration or intracerebroventricular pretreatment with other drugs and continued 1 h after (±)-epibatidine administration. Intracerebroventricularly administered (±)-epibatidine elevated plasma catecholamines and prolonged ICI without affecting MVP, and these changes were suppressed by intracerebroventricularly pretreated mecamylamine (non-selective nAChR antagonist). Acute bilateral adrenalectomy abolished the (±)-epibatidine-induced elevation of plasma catecholamines, but had no effect on the (±)-epibatidine-induced ICI prolongation. The latter was suppressed by intracerebroventricularly pretreated methyllycaconitine (selective α7-nAChR antagonist), SR95531 (GABAA antagonist), and SCH50911 (GABAB antagonist), but not by dihydro-β-erythroidine (selective α4β2-nAChR antagonist). Intracerebroventricularly administered PHA568487 (selective α7-nAChR agonist) prolonged ICI without affecting MVP, similar to (±)-epibatidine. These results suggest that stimulation of brain α7-nAChRs suppresses the rat micturition through brain GABAA/GABAB receptors, independently of the sympatho-adrenomedullary outflow modulation.

Accumulating evidence indicates time-of-day variations in ischemic neuronal injury. Under ischemic conditions, Zn

INTRODUCTION AND OBJECTIVE:In the lower urinary tract, nitric oxide (NO) is well known as a relaxation factor in the urethra. On the other hand, in the central nervous system, NO is reported to hav...

Microglia, the resident immune cells of the central nervous system, can display a pro-inflammatory M1 phenotype or an anti-inflammatory M2 phenotype. Arginase (Arg)-1 expressed in interleukin-4 (IL-4)-induced M2 microglia reduces nitric oxide (NO) production by competing with inducible NO synthase for l-arginine, which contributes to the attenuation of brain inflammation. Although previous studies have indicated that brain zinc promotes M1 activation, the effect of zinc on M2 microglial activation remains to be determined. In the present study, murine primary microglia treated with 10 ng mL-1 IL-4 exhibited increased Arg-1 mRNA expression and levels of intracellular free zinc. Chelation of this increased intracellular free zinc by the cell permeable zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) aggravated the IL-4-induced mRNA expression and enzymatic activity of Arg-1. However, the cell impermeable zinc chelator CaEDTA had no effect on Arg-1 expression or cytosolic levels of free zinc in IL-4-induced M2-polarized microglia. Furthermore, treatment with IL-4 resulted in upregulation of phagocytic activity in microglia, while administration of TPEN abolished IL-4-induced phagocytic activity. Moreover, this effect was reversed vial-arginine supplementation. These findings suggest that IL-4 induces an increase in intracellular free zinc in microglia, which may act as a negative regulator of IL-4-induced Arg-1 expression, and that such negative regulation is essential for microglial phagocytic activity.

Zinc, an essential trace element, plays an important role in a large number of biological functions. In mammalian brain, whereas the majority of brain zinc is bound to proteins including metallothionein, about 5-15% is stored in presynaptic vesicles of glutamatergic neurons throughout the forebrain, especially in the hippocampus, in a relatively free state. Thus, free zinc (Zn2+) concentration in the brain is considered to be regulated in order to maintain normal brain functions such as learning and memory. On the other hand, brain Zn2+ dyshomeostasis has been recognized as a mechanism for neuronal injury in brain disorders including Alzheimer's disease and brain ischemia. In particular, after transient brain ischemia, Zn2+ accumulates in hippocampal neurons via a zinc transport system, or via release from cytosolic zinc-binding proteins, which results in neuronal cell death. Recently, it has been demonstrated that Zn2+ dyshomeostasis also occurs in glial cells such as microglia, astrocytes and oligodendrocytes after brain ischemia. In oligodendrocytes, ischemic insult triggers intracellular Zn2+ accumulation, resulting in cell death via mitochondrial dysfunction. Increased extracellular Zn2+ inhibits astrocytic glutamate uptake. In addition, extracellular Zn2+ massively released from ischemic neurons primes microglia to enhance production of pro-inflammatory cytokines in response to stimuli that trigger M1 activation. This review aims to describe the impact of brain Zn2+ dyshomeostasis on alterations in glial cell survival and functions in post-ischemic brains.

Background Glial cells such as astrocytes and microglia play an important role in the central nervous system via communication between these glial cells. Activated microglia can exhibit either the inflammatory M1 phenotype or the anti-inflammatory M2 phenotype, which influences astrocytic neuroprotective functions, including engulfment of cell debris. Recently, extracellular zinc has been shown to promote the inflammatory M1 phenotype in microglia through intracellular zinc accumulation and reactive oxygen species (ROS) generation. Purpose Here, we investigated whether the zinc-enhanced inflammatory M1 phenotype of microglia affects the astrocytic engulfing activity. Methods Engulfing activity was assessed in astrocytes treated with microglial-conditioned medium (MCM) from lipopolysaccharide (LPS)-activated or from ZnCl2-pretreated LPS-activated M1 microglia. The effect of zinc on microglia phenotype was also validated using the zinc chelator N,N,N’,N’-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and the ROS scavenger Trolox. Results Although treatment of astrocytes with LPS showed no significant effect on the engulfing activity, MCM from LPS-induced M1 microglia increased the beads uptake by astrocytes. This increased uptake activity was suppressed when MCM from LPS-induced M1 microglia pretreated with ZnCl2 was applied to astrocytes, which was further abolished by the intracellular zinc chelator TPEN and the ROS scavenger Trolox. In addition, expression of P2×7 receptors (P2×7R) was increased in astrocytes treated with MCM derived from M1 microglia but not in the M1 microglia pretreated with ZnCl2. Conclusion These findings suggest that zinc pre-treatment abolishes the ability of LPS-induced M1 microglia to increase the engulfing activity in astrocytes via alteration of astrocytic P2×7R.

INTRODUCTION AND OBJECTIVES:Psychological stress exacerbates symptoms of bladder dysfunction. We previously reported that epibatidine (EP), a nicotinic acetylcholine receptor (nAChR) agonist, centr...

INTRODUCTION AND OBJECTIVES:Psychological stress is involved in the development of the lower urinary tract symptoms. Our previous reports showed that centrally administered a stress-related neurope...

Accumulating evidence indicates time-of-day variations in ischemic neuronal injury. Under ischemic conditions, Zn2+ is massively released from hippocampal glutamatergic neurons, and intracellular Zn2+ accumulation results in neuron death. Notably, excitatory amino acid carrier 1 (EAAC1), known as a cysteine transporter, is involved in Zn2+ homeostasis, and its expressions exhibit a diurnal fluctuation. This study aimed to investigate whether time of day of an ischemic insult affects Zn2+ accumulation and neuronal injury and determine whether altered Zn2+ accumulation is modulated by EAAC1 diurnal fluctuation in the hippocampus in a mouse model of ischemic stroke. Mice subjected to transient global ischemia for 40 min at Zeitgeber time 18 (ZT18) (23:00) exhibited reduced Zn2+ accumulation and neuronal death in the hilar region of the hippocampus compared to those at ZT4 (09:00). The EAAC1 protein expression in the hippocampus was increased at ZT18 relative to ZT4. Intracerebroventricular injection of a non-selective excitatory amino acid transporter inhibitor, DL-threo-β-benzyloxyaspartate, or a selective EAAC1 inhibitor, L-aspartic acid β-hydroxamate, increased ischemia-induced Zn2+ accumulation and neuronal death in the hilus at ZT18. These findings suggest that ischemia-induced Zn2+ accumulation displays circadian fluctuations through diurnal variations in EAAC1 expressions and affects susceptibility to ischemic neuronal injury in the hippocampal hilar region.

Aims To clarify the roles of hydrogen sulfide (H2 S), an endogenous gasotransmitter, in the rat bladder and prostate, we investigated the distribution of enzymes related to H2 S biosynthesis (cystathionine β-synthase [CBS], cystathionine γ-lyase [CSE], 3-mercaptopyruvate sulfurtransferase [MPST], cysteine aminotransferase [CAT], and D-amino acid oxidase [DAO]) and the content of H2 S. We also investigated the effects of H2 S donors (NaHS and GYY4137) on the contractility of both tissues and on micturition. Methods The distribution of these enzymes was investigated by real-time PCR, Western blot, and immunohistochemistry. Tissue H2 S content was measured by the methylene blue method. The effects of NaHS (1 × 10-9 to 3 × 10-4 M) were evaluated on carbachol (10-5 M)-induced pre-contracted bladder strips, and on noradrenaline (10-5 M)-induced pre-contracted prostate strips, which were pretreated with propranolol (10-6 M). In addition, in urethane-anesthetized male Wistar rats, the effects of intravesically instilled GYY4137 (10-8 , 10-7 , and 10-6 M) on micturition were evaluated by cystometry. Results MPST and CAT were detected in the bladder and prostate, CBS was only detected in the prostate, while CSE and DAO were not detected in both tissues. Immunoreactivity of these enzymes was mainly detected in the urothelium and smooth muscle layer of the bladder and in the prostate glandular epithelium. H2 S was detected in both tissues. NaHS dose-dependently induced relaxation of pre-contracted bladder and prostate strips. Intravesically instilled GYY4137 significantly prolonged intercontraction intervals. Conclusions It is possible that H2 S can function as an endogenous relaxation factor in the rat bladder and prostate.

Extracellular zinc, which is released from hippocampal neurons in response to brain ischaemia, triggers morphological changes in microglia. Under ischaemic conditions, microglia exhibit two opposite activation states (M1 and M2 activation), which may be further regulated by the microenvironment. We examined the role of extracellular zinc on M1 activation of microglia. Pre-treatment of microglia with 30–60 μM ZnCl2 resulted in dose-dependent increases in interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNFα) secretion when M1 activation was induced by lipopolysaccharide administration. In contrast, the cell-permeable zinc chelator TPEN, the radical scavenger Trolox, and the P2X7 receptor antagonist A438079 suppressed the effects of zinc pre-treatment on microglia. Furthermore, endogenous zinc release was induced by cerebral ischaemia–reperfusion, resulting in increased expression of IL-1β, IL-6, TNFα, and the microglial M1 surface marker CD16/32, without hippocampal neuronal cell loss, in addition to impairments in object recognition memory. However, these effects were suppressed by the zinc chelator CaEDTA. These findings suggest that extracellular zinc may prime microglia to enhance production of pro-inflammatory cytokines via P2X7 receptor activation followed by reactive oxygen species generation in response to stimuli that trigger M1 activation, and that these inflammatory processes may result in deficits in object recognition memory.