Simultaneous disturbance of NHE1 and LOXL2 decreases tumorigenicity of head and neck squamous cell carcinoma

OBJECTIVE

Although there have been brilliant advancements in the practical application of therapies targeting immune checkpoints, achieving success in targeting the microenvironment remains elusive. In this study, we aimed to address this gap by focusing on Na+ / H+ exchanger 1 (NHE1) and Lysyl Oxidase Like 2 (LOXL2), which are upregulated in head and neck squamous cell carcinoma (HNSCC) cells.

METHODS

The malignancy of a metastatic human HNSCC cell line was assessed in a mouse tongue cancer xenograft model by knocking down (KD) NHE1, responsible for regulating intracellular pH, and LOXL2, responsible for extracellular matrix (ECM) reorganization via cross-linking of ECM proteins. In addition to assessing changes in PD-L1 levels and collagen accumulation following knockdown, the functional status of the PD-L1 / PD-1 immune checkpoint was examined through co-culture with NK92MI, a PD-1 positive phagocytic human Natural Killer (NK) cell line.

RESULTS

The tumorigenic potential of each single KD cell line was similar to that of the control cells, whereas the potential was attenuated in cells with simultaneous KD of both factors (double knockdown [dKD]). Additionally, we observed decreased PD-L1 levels in NHE1 KD cells and compromised collagen accumulation in LOXL2 KD and dKD cells. NK92MI cells exhibited phagocytic activity toward HNSCC cells in co-culture, and the number of remaining dKD cells after co-culture was the lowest in comparison to the control and single KD cells.

CONCLUSION

This study demonstrated the possibility of achieving efficient anti-tumor effects by simultaneously disturbing multiple factors involved in the modification of the tumor microenvironment.

A dopamine D1-like receptor-specific agonist improves the survival of septic mice

In this study, a murine sepsis model was developed using the cecum ligation and puncture (CLP) technique. The expression of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) in the brain increased 6 h after CLP but decreased 24 h later when elevated endogenous dopamine levels in the brain were sustained. Methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride reduced dopamine levels in the striatum and increased mortality in septic mice. Dopamine D1-like receptors were significantly expressed in the brain, but not in the lungs. Intraperitoneally administered SKF-81297 (SKF), a blood-brain barrier-permeable D1-like receptor agonist, prevented CLP-induced death of septic mice with ameliorated acute lung injury and cognitive dysfunction and suppressed TNF-α and IL-1β expression. The D1-like receptor antagonist SCH-23390 abolished the anti-inflammatory effects of SKF. These data suggest that D1-like receptor-mediated signals in the brain prevent CLP-induced inflammation in both the brain and the periphery.

Berberine as a potential enhancer for 5-ALA-mediated fluorescence in glioblastoma: increasing detectability of infiltrating glioma stem cells to optimize 5-ALA-guided surgery

OBJECTIVE

The prognosis of glioblastoma (GBM) correlates with residual tumor volume after surgery. In fluorescence-guided surgery, 5-aminolevulinic acid (ALA) has been used to maximize resection while avoiding neurological morbidity. However, not all tumor cells, particularly glioma stem cells (GSCs), display 5-ALA-mediated protoporphyrin IX (PpIX) fluorescence (5-ALA fluorescence). The authors searched for repositioned drugs that affect mitochondrial functions and energy metabolism, identifying berberine (BBR) as a potential enhancer of 5-ALA fluorescence. In this study, they investigated whether BBR can enhance 5-ALA fluorescence in GSCs and whether BBR can be applied to clinical practice as a 5-ALA fluorescence enhancer.

METHODS

The effects of BBR on 5-ALA fluorescence in glioma and GSCs were evaluated by flow cytometry (fluorescence-activated cell sorting [FACS]) analysis. As 5-ALA is metabolized for heme synthesis, the effects of BBR on mRNA expressions of 7 enzymes in the heme-synthesis pathway were analyzed. Enzymes showing significantly higher expression than control in all cells were identified and protein analysis was performed. To examine clinical availability, the detectability and cytotoxicity of BBR in tumor-transplanted mice were analyzed.

RESULTS

Fluorescence microscopy revealed much more intense 5-ALA fluorescence in both GSCs and non-stem cells with 5-ALA and BBR than with 5-ALA alone. FACS showed that BBR greatly enhanced 5-ALA fluorescence compared with 5-ALA alone, and enhancement was much higher for GSCs than for glioma cells. Among the 7 enzymes examined, BBR upregulated mRNA expressions of ALA synthetase 1 (ALAS1) more highly in all cells, and activated ALAS1 through deregulating ALAS1 activity inhibited by the negative feedback of heme. An in vivo study showed that 5-ALA fluorescence with 5-ALA and BBR was significantly stronger than with 5-ALA alone, and the sensitivity and specificity of BBR-enhanced fluorescence were both 100%. In addition, BBR did not show any cytotoxicity for normal brain tissue surrounding the tumor mass.

CONCLUSIONS

BBR enhanced 5-ALA-mediated PpIX fluorescence by upregulating and activating ALAS1 through deregulation of negative feedback inhibition by heme. BBR is a clinically used drug with no side effects. BBR is expected to significantly augment fluorescence-guided surgery and photodynamic therapy.

Anti-inflammatory effects of dopamine on microglia and a D1 receptor agonist ameliorates neuroinflammation of the brain in a rat delirium model

Microglia play a central role in neuroinflammatory processes by releasing proinflammatory mediators. This process is tightly regulated along with neuronal activities, and neurotransmitters may link neuronal activities to the microglia. In this study, we showed that primary cultured rat microglia express the dopamine (DA) D1 receptor (D1R) and D4R, but not D2R, D3R, or D5R. In response to a D1R-specific agonist SKF-81297 (SKF), the cultured microglia exhibited increased intracellular cAMP levels. DA and SKF suppressed lipopolysaccharide (LPS)-induced expression of interleukin-1β (IL-1β) and tumor necrosis α (TNFα) in cultured microglia. Microglia in the normal mature rat prefrontal cortex (PFC) were sorted and significant expression of D1R, D2R, and D4R was observed. A delirium model was established by administering LPS intraperitoneally to mature male Wistar rats. The model also displayed sleep-wake disturbances as revealed by electroencephalogram and electromyogram recordings as well as increased expression of IL-1β and TNFα in the PFC. DA levels were increased in the PFC 21 h after LPS administration. Increased cytokine expression was observed in sorted microglia from the PFC of the delirium model; however, TNFα, but not IL-1β expression, was abruptly decreased 21 h after LPS administration in the delirium model, whereas DA levels were increased. A D1R antagonist SCH23390 partially abolished the TNFα expression change. This suggests that endogenous DA may play a role in suppressing neuroinflammation. Administration of the DA precursor L-DOPA or SKF to the delirium model rats inhibited the expression of IL-1β and TNFα. The simultaneous administration of clozapine, a D4R antagonist, strengthened the suppressive effects of L-DOPA. These results suggest that D1R mediates the suppressive effects of LPS-induced neuroinflammation, in which microglia may play an important role. Agonists for D1R may be effective for treating delirium.

Treadmill Exercise as a Preventive Measure Against Age-Related Anxiety and Social Behavioral Disorders in Rats: When Is It Worth Starting?

OBJECTIVE

To determine the appropriate time points to start regular exercise which could reduce age-related anxiety and impaired social behavior.

METHODS

For this study, 8-week-old male Wistar rats were divided into three groups: no exercise (NoEX), short-term exercise (S-Ex), and long-term exercise (L-Ex) groups. S-Ex-group rats started treadmill exercise at 12 months of age, while L-Ex rats started from at 2 months of age. Exercise rats were forced to walk on the treadmill three times per week, with 1- to 2-day intervals for 10 minutes during the first 2 weeks, at 10 m/min until 17 months of age, and at 8 m/min thereafter. At 19 months of age, behavioral tests were performed to assess the effects of exercise on age-induced behavioral change as well as quantitative polymerase chain reaction were done to uncover the mechanism behind the behavioral changes.

RESULTS

Anxiety-like behavior was improved by long-term exercise. Additionally, rats belonging to the S-Ex and L-Ex groups showed improved social behavior and increased curiosity about interesting objects. The qPCR data showed that treadmill exercise suppressed the expression of immediate-early genes in the prefrontal cortex of the aged rats.

CONCLUSION

This study suggests that long-term exercise represses early response genes, and in this way, it increases resistance to stress, diminishes anxiety-related behavior, and improves social behavior. These findings underscore the need to consider appropriate time to start exercise to prevent stress induced anxiety related behavior.

Microglial re-modeling contributes to recovery from ischemic injury of rat brain: A study using a cytokine mixture containing granulocyte-macrophage colony-stimulating factor and interleukin-3

Ischemic stroke is a leading cause of mortality and permanent disability. Chronic stroke lesions increase gradually due to the secondary neuroinflammation that occurs following acute ischemic neuronal degeneration. In this study, the ameliorating effect of a cytokine mixture consisting of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-3 was evaluated on ischemic brain injury using a rat stroke model prepared by transient middle cerebral artery occlusion (tMCAO). The mixture reduced infarct volume and ameliorated ischemia-induced motor and cognitive dysfunctions. Sorted microglia cells from the ischemic hemisphere of rats administered the mixture showed reduced mRNA expression of tumor necrosis factor (TNF)-α and IL-1β at 3 days post-reperfusion. On flow cytometric analysis, the expression of CD86, a marker of pro-inflammatory type microglia, was suppressed, and the expression of CD163, a marker of tissue-repairing type microglia, was increased by the cytokine treatment. Immunoblotting and immunohistochemistry data showed that the cytokines increased the expression of the anti-apoptotic protein Bcl-xL in neurons in the ischemic lesion. Thus, the present study demonstrated that cytokine treatment markedly suppressed neurodegeneration during the chronic phase in the rat stroke model. The neuroprotective effects may be mediated by phenotypic changes of microglia that presumably lead to increased expression of Bcl-xL in ischemic lesions, while enhancing neuronal survival.

Surgical stress quickly affects the numbers of circulating B-cells and neutrophils in murine septic and aseptic models through a β2 adrenergic receptor

Sepsis is a pathology accompanied by increases in myeloid cells and decreases in lymphoid cells in circulation. In a murine sepsis model induced by cecum ligation and puncture (CLP), increasing numbers of neutrophils and decreasing levels of B-cells in circulation are among the earliest changes in the immune system. However, to date, the mechanisms for these changes remain to be elucidated. The study here sought to elucidate mechanisms underlying the changes in the leukocyte levels after CLP and also to determine what, if any, role for an involvement of the sympathetic nervous system (SNS). Here, male C57/BL6 mice were subjected to CLP or sham-CLP (abdominal wall incised, but cecum was not punctured). The changes in the number of circulating leukocytes over time were then investigated using flow cytometry. The results showed that a sham-CLP led to increased polymorphonuclear cells (PMN; most of which are neutrophils) and decreased B-cells in the circulation to an extent similar to that induced by CLP. Effects of adrenergic agonists and antagonists, as well as of adrenalectomy, were also examined in mice that underwent CLP or sham-CLP. Administering adrenaline or a β₂ adrenergic receptor agonist (clenbuterol) to mice 3 h before sacrifice produced almost identical changes to as what was seen 2 h after performing a sham-CLP. In contrast, giving a β₂ adrenergic receptor antagonist ICI118,551 1 h before a CLP or sham-CLP suppressed the expected changes 2 h after the operations. Noradrenaline and an α1 adrenergic receptor agonist phenylephrine did not exert significant effects. Adrenalectomy 24 h before a sham-CLP significantly abolished the expected sham-CLP-induced changes seen earlier. Clenbuterol increased splenocyte expression of Cxcr4 (a chemokine receptor gene); adrenalectomy abolished sham-CLP-induced Cxcr4 expression. A CXCR4 antagonist AMD3100 repressed the sham-CLP-induced changes. From these results, it may be concluded that sepsis-induced activation of the SNS may be one cause for immune dysfunction in sepsis - regardless of the pathogenetic processes.

Zonisamide Ameliorates Microglial Mitochondriopathy in Parkinson’s Disease Models

Mitochondrial dysfunction and exacerbated neuroinflammation are critical factors in the pathogenesis of both familial and non-familial forms of Parkinson’s disease (PD). This study aims to understand the possible ameliorative effects of zonisamide on microglial mitochondrial dysfunction in PD. We prepared 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and lipopolysaccharide (LPS) co-treated mouse models of PD to investigate the effects of zonisamide on mitochondrial reactive oxygen species generation in microglial cells. Consequently, we utilised a mouse BV2 cell line that is commonly used for microglial studies to determine whether zonisamide could ameliorate LPS-treated mitochondrial dysfunction in microglia. Flow cytometry assay indicated that zonisamide abolished microglial reactive oxygen species (ROS) generation in PD models. Extracellular flux assays showed that LPS exposure to BV2 cells at 1 μg/mL drastically reduced the mitochondrial oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Zonisamide overcame the inhibitory effects of LPS on mitochondrial OCR. Our present data provide novel evidence on the ameliorative effect of zonisamide against microglial mitochondrial dysfunction and support its clinical use as an antiparkinsonian drug.

Insomnia and depressive behavior of MyD88-deficient mice: Relationships with altered microglial functions

Myeloid differentiation primary response gene 88 (MyD88) is essential for microglial activation. Despite the significant role of microglia in regulating sleep homeostasis, the contribution of MyD88 to sleep is yet to be determined. To address this, we performed electroencephalographic and electromyographic recordings on MyD88-KO mice and wild-type mice to investigate their sleep/wake cycles. In the daytime, MyD88-KO mice exhibited prolonged wakefulness and shorter non-rapid eye movement sleep duration. Tail suspension and sucrose preference tests revealed that MyD88-KO mice displayed a depressive-like phenotype. We determined monoamines in the prefrontal cortex (PFC) using high-performance liquid chromatography and observed a decreased content of serotonin in the PFC of MyD88-KO mice. Flow cytometry revealed that CD11b, CD45, and F4/80 expressions were elevated at Zeitgeber time (ZT) 1 compared to at ZT13 only in wild-type mice. Furthermore, MFG-E8 and C1qB-tagged synapses were enhanced at ZT1 in the PFC of wild-type mice but not in MyD88-KO mice. Primary cultured microglia from MyD88-KO mice revealed decreased phagocytic ability. These findings indicate that genetic deletion of MyD88 induces insomnia and depressive behavior, at least in part, by affecting microglial homeostasis functions and lowering the serotonergic neuronal output.

Microglia and the Aging Brain: Are Geriatric Microglia Linked to Poor Sleep Quality?

Poor sleep quality and disrupted circadian behavior are a normal part of aging and include excessive daytime sleepiness, increased sleep fragmentation, and decreased total sleep time and sleep quality. Although the neuronal decline underlying the cellular mechanism of poor sleep has been extensively investigated, brain function is not fully dependent on neurons. A recent antemortem autographic study and postmortem RNA sequencing and immunohistochemical studies on aged human brain have investigated the relationship between sleep fragmentation and activation of the innate immune cells of the brain, microglia. In the process of aging, there are marked reductions in the number of brain microglial cells, and the depletion of microglial cells disrupts circadian rhythmicity of brain tissue. We also showed, in a previous study, that pharmacological suppression of microglial function induced sleep abnormalities. However, the mechanism underlying the contribution of microglial cells to sleep homeostasis is only beginning to be understood. This review revisits the impact of aging on the microglial population and activation, as well as microglial contribution to sleep maintenance and response to sleep loss. Most importantly, this review will answer questions such as whether there is any link between senescent microglia and age-related poor quality sleep and how this exacerbates neurodegenerative disease.

Chloride intracellular channel protein 2 is secreted and inhibits MMP14 activity, while preventing tumor cell invasion and metastasis

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CLIC2 is highly expressed in benign, less invasive and less metastatic tumors.

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Forced expression of CLIC2 prevents metastasis and invasion in animal tumor models.

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CLIC2 is associated with decreased vascular permeability in tumor masses.

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CLIC2, a secretable soluble protein, can bind to and inhibit MMP14.

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Extracellular CLIC2 can suppress malignant cell invasion.

The abilities to invade surrounding tissues and metastasize to distant organs are the most outstanding features that distinguish malignant from benign tumors. However, the mechanisms preventing the invasion and metastasis of benign tumor cells remain unclear. By using our own rat distant metastasis model, gene expression of cells in primary tumors was compared with that in metastasized tumors. Among many distinct gene expressions, we have focused on chloride intracellular channel protein 2 (CLIC2), an ion channel protein of as-yet unknown function, which was predominantly expressed in the primary tumors. We created CLIC2 overexpressing rat glioma cell line and utilized benign human meningioma cells with naturally high CLIC2 expression. CLIC2 was expressed at higher levels in benign human brain tumors than in their malignant counterparts. Moreover, its high expression was associated with prolonged survival in the rat metastasis and brain tumor models as well as with progression-free survival in patients with brain tumors. CLIC2 was also correlated with the decreased blood vessel permeability likely by increased contents of cell adhesion molecules. We found that CLIC2 was secreted extracellularly, and bound to matrix metalloproteinase (MMP) 14. Furthermore, CLIC2 prevented the localization of MMP14 in the plasma membrane, and inhibited its enzymatic activity. Indeed, overexpressing CLIC2 and recombinant CLIC2 protein effectively suppressed malignant cell invasion, whereas CLIC2 knockdown reversed these effects. Thus, CLIC2 suppress invasion and metastasis of benign tumors at least partly by inhibiting MMP14 activity.

Chronic constriction injury of the sciatic nerve in rats causes different activation modes of microglia between the anterior and posterior horns of the spinal cord

Chronic constriction injury of the sciatic nerve is frequently considered as a cause of chronic neuropathic pain. Marked activation of microglia in the posterior horn (PH) has been well established with regard to this pain. However, microglial activation in the anterior horn (AH) is also strongly induced in this process. Therefore, in this study, we compared the differential activation modes of microglia in the AH and PH of the lumbar cord 7 days after chronic constriction injury of the left sciatic nerve in Wistar rats. Microglia in both the ipsilateral AH and PH demonstrated increased immunoreactivity of the microglial markers Iba1 and CD11b. Moreover, abundant CD68⁺ phagosomes were observed in the cytoplasm. Microglia in the AH displayed elongated somata with tightly surrounding motoneurons, whereas cells in the PH displayed a rather ameboid morphology and were attached to myelin sheaths rather than to neurons. Microglia in the AH strongly expressed NG2 chondroitin sulfate proteoglycan. Despite the tight attachment to neurons in the AH, a reduction in synaptic proteins was not evident, suggesting engagement of the activated microglia in synaptic stripping. Myelin basic protein immunoreactivity was observed in the phagosomes of activated microglia in the PH, suggesting the phagocytic removal of myelin. CCI caused both motor deficit and hyperalgesia that were evaluated by applying BBB locomotor rating scale and von Frey test, respectively. Motor defict was the most evident at postoperative day1, and that became less significant thereafter. By contrast, hyperalgesia was not severe at day 1 but it became worse at least by day 7. Collectively, the activation modes of microglia were different between the AH and PH, which may be associated with the difference in the course of motor and sensory symptoms.

B lymphocytopenia and Bregs in a not-to-die murine sepsis model

Sepsis is a leading cause of mortality in intensive care units due to multi-organ failure caused by dysregulated immune reactions. In this study, kinetic changes in the immune system were analyzed for 72 h in cecal ligation and puncture (CLP)-induced septic mice while preventing animal death by keeping body temperature. Increase of myeloid cells and decrease of B cells in circulation at 6 h after CLP were markedly observed. At the same time point, interleukin (IL)-10 expressing CD5⁺ regulatory B cells (Bregs) appeared. IL-10 and programmed death-ligand 1 (PD-L1) mRNA as well as IL-1β, IL-6 and interferon γ (IFNγ) mRNA was increased in the spleen at 6 h. A gradual decrease in Bcl-2 and abrupt increase of Bim expression in the spleen at the late phase were also found. These results showed that B lymphocytopenia with the appearance of Bregs is the earliest event, likely leading to immunoparalysis in sepsis.

Aggravating effects of treadmill exercises during the early-onset period in a rat traumatic brain injury model: When should rehabilitation exercises be initiated?

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A traumatic brain injury model was prepared in rats by stab wounding.

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Rats were forced to walk slowly on a treadmill once for 10 min at 24 h or 48 h after wounding.

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Exercise, particularly at 24 h, aggravated motor impairment while increasing the expression of proinflammatory factors.

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Exercise for rehabilitation should be initiated after 48 h of severe brain injury onset.

Physical exercise is one of the best interventions for improving traumatic brain injury (TBI) outcomes. However, an argument has been raised regarding the timing at which physical exercise should be initiated. In this study, male Wistar rats were subjected to stab wounding of the right hemisphere to develop a TBI model and were forced to walk once on a treadmill at a 5-m/min pace at 24 h or 48 h after TBI for 10 min. Injured brain tissue was dissected after TBI to evaluate the effects of exercise. Behavioral abnormalities and motor impairment were assessed by various behavioral tests between 2 and 3 weeks after TBI. Exercise did not affect the circulating corticosterone levels and the weight of the adrenal glands. Exercise particularly that at 24 h, worsened the motor impairment of the left forelimbs. Quantitative reverse-transcription polymerase chain reaction showed that exercise at 24 h increased proinflammatory cytokines and chemokines on the third day while suppressing the proinflammatory reactions on the fourth day. Exercise at both time points decreased expression of transforming growth factor (TGF) β1 and its receptor TGFβR1. Exercise at 24 h increased phosphorylation of IκB kinase on the fourth day, which may be correlated with the decreased effects of TGFβ1. Even a low-intensity exercise activity could cause deleterious effects when it is initiated within 48 h after the onset of severe TBI, probably because of the resulting proinflammatory effects. Therefore, rehabilitation exercise programs should be initiated after 48 h of TBI onset.

Phagocytic elimination of synapses by microglia during sleep

Synaptic strength reduces during sleep, but the underlying mechanisms of this process are unclear. This study showed reduction of synaptic proteins in rat prefrontal cortex (PFC) at AM7 or Zeitgeber Time (ZT0), when the light phase or sleeping period for rats started. At this time point, microglia were weakly activated, displaying larger and more granular somata with increased CD11b expression compared with those at ZT12, as revealed by flow cytometry. Expression of opsonins, such as complements or MFG-E8, matrix metalloproteinases, and microglial markers at ZT0 were increased compared with that at ZT12. Microglia at ZT0 phagocytosed synapses, as revealed by immunohistochemical staining. Immunoblotting detected more synapsin I in the isolated microglia at ZT0 than at ZT12. Complement C3- or MFG-E8-bound synapses were the most abundant at ZT0, some of which were phagocytosed by microglia. Systemic administration of synthetic glucocorticoid dexamethasone reduced microglial size, granularity and CD11b expression at ZT0, resembling microglia at ZT12, and increased synaptic proteins and decreased the sleeping period. Noradrenaline (NA) suppressed glutamate-induced phagocytosis in primary cultured microglia. Systemic administration of the brain monoamine-depleting agent reserpine decreased NA content and synapsin I expression in PFC, and increased expression of microglia markers, C3 and MFG-E8, while increasing the sleeping period. A NA precursor l-threo-dihydroxyphenylserine abolished the reserpine-induced changes. These results suggest that microglia may eliminate presumably weak synapses during every sleep phase. The circadian changes in concentrations of circulating glucocorticoids and brain NA might be correlated with the circadian changes of microglial phenotypes and synaptic strength.

Chloride intracellular channel protein 2 in cancer and non-cancer human tissues: relationship with tight junctions

Chloride intracellular channel protein 2 (CLIC2) belongs to the CLIC family of conserved metazoan proteins. Although CLICs have been identified as chloride channels, they are currently considered multifunctional proteins. CLIC2 is the least studied family member. We investigated CLIC2 expression and localization in human hepatocellular carcinoma, metastatic colorectal cancer in the liver, and colorectal cancer. Significant expression of mRNAs encoding CLIC1, 2, 4, and 5 were found in the human tissues, but only CLIC2 was predominantly expressed in non-cancer tissues surrounding cancer masses. Fibrotic or dysfunctional (aspartate aminotransferase ≥40) non-cancer liver tissues and advanced stage HCC tissues expressed low levels of CLIC2. Endothelial cells lining blood vessels but not lymphatic vessels in non-cancer tissues expressed CLIC2 as well as high levels of the tight junction proteins claudins 1 and 5, occludin, and ZO-1. Most endothelial cells in blood vessels in cancer tissues had very low expressions of CLIC2 and tight junction proteins. CD31⁺/CD45⁻ endothelial cells isolated from non-cancer tissues expressed mRNAs encoding CLIC2, claudin 1, occludin and ZO-1, while similar cell fractions from cancer tissues had very low expressions of these molecules. Knockdown of CLIC2 expression in human umbilical vein endothelial cells (HUVECs) allowed human cancer cells to transmigrate through a HUVEC monolayer. These results suggest that CLIC2 may be involved in the formation and/or maintenance of tight junctions and that cancer tissue vasculature lacks CLIC2 and tight junctions, which allows the intravasation of cancer cells necessary for hematogenous metastasis.

Behavioral tests predicting striatal dopamine level in a rat hemi-Parkinson's disease model

Parkinson's disease (PD) is a frequent neurodegenerative disease causing bradykinesia, tremor, muscle rigidity and postural instability. Although its main pathology is progressive dopaminergic (DArgic) neuron loss in the substantia nigra, motor deficits are thought not to become apparent until most DArgic neurons are lost, probably due to compensatory mechanisms that overcome the decline of DA level in the striatum. Even in animal PD models, it is difficult to detect motor deficits when most DArgic neurons are functional. In this study, we performed various behavioral tests (apomorphine-induced rotation, cylinder, forepaw adjustment steps (FAS), beam walking, rota-rod, and open-field), using 6-hydroxydopamine (OHDA) and lipopolysaccharide (LPS)-induced hemi-PD model rats with various striatal DA levels, to find the best way to predict the DA level from earlier disease stages. Different from the 6-OHDA-induced model, reduction in the striatal DA levels in the LPS-model was less significant. Among the behavioral tests, data from cylinder and FAS tests, which evaluate forelimb movements, best correlated with decline of the DA level. They also correlated well with decreased body weight gain. The beam and apomorphine tests showed less significant correlation than the cylinder and FAS tests. Open-field and rota-rod tests were not useful. Expressional levels of mRNA encoding tyrosine hydroxylase (TH), a marker of DArgic neurons, correlated well with the DA level. Metabotropic glutamate receptor 4 mRNA expression correlated with the striatal DA level and may be related to compensatory mechanisms. These results suggest that motor impairments of PD should be evaluated by forelimb movements, or hands and forearms in clinical settings, rather than movement of the body or large joints. The combination of cylinder and FAS tests may be the best to evaluate the rat PD models, in which many DArgic neurons survive.

Comparison of the detrimental features of microglia and infiltrated macrophages in traumatic brain injury: A study using a hypnotic bromovalerylurea

Microglia and blood-borne macrophages in injured or diseased brains are difficult to distinguish because they share many common characteristics. However, the identification of microglia-specific markers and the use of flow cytometry have recently made it easy to discriminate these types of cells. In this study, we analyzed the features of blood-borne macrophages, and activated and resting microglia in a rat traumatic brain injury (TBI) model. Oxidative injury was indicated in macrophages and neurons in TBI lesions by the presence of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Generation of mitochondrial reactive oxygen species (ROS) was markedly observed in granulocytes and macrophages, but not in activated or resting microglia. Dihydroethidium staining supported microglia not being the major source of ROS in TBI lesions. Furthermore, macrophages expressed NADPH oxidase 2, interleukin-1β (IL-1β), and CD68 at higher levels than microglia. In contrast, microglia expressed transforming growth factor β1 (TGFβ1), interleukin-6 (IL-6), and tumor necrosis factor α at higher levels than macrophages. A hypnotic, bromovalerylurea (BU), which has anti-inflammatory effects, reduced both glycolysis and mitochondrial oxygen consumption. BU administration inhibited chemokine CCL2 expression, accumulation of monocytes/macrophages, 8-OHdG generation, mitochondrial ROS generation, and proinflammatory cytokine expression, and markedly ameliorated the outcome of the TBI model. Yet, BU did not inhibit microglial activation or expression of TGFβ1 and insulin-like growth factor 1 (IGF-1). These results indicate that macrophages are the major aggravating cell type in TBI lesions, in particular during the acute phase. Activated microglia may even play favorable roles. Reduction of cellular energy metabolism in macrophages and suppression of CCL2 expression in injured tissue may lead to amelioration of TBI.

Treadmill exercise ameliorates ischemia-induced brain edema while suppressing Na⁺/H⁺ exchanger 1 expression

Exercise may be one of the most effective and sound therapies for stroke; however, the mechanisms underlying the curative effects remain unclear. In this study, the effects of forced treadmill exercise with electric shock on ischemic brain edema were investigated. Wistar rats were subjected to transient (90 min) middle cerebral artery occlusion (tMCAO). Eighty nine rats with substantially large ischemic lesions were evaluated using magnetic resonance imaging (MRI) and were randomly assigned to exercise and non-exercise groups. The rats were forced to run at 4-6m/s for 10 min/day on days 2, 3 and 4. Brain edema was measured on day 5 by MRI, histochemical staining of brain sections and tissue water content determination (n=7, each experiment). Motor function in some rats was examined on day 30 (n=6). Exercise reduced brain edema (P<0.05-0.001, varied by the methods) and ameliorated motor function (P<0.05). The anti-glucocorticoid mifepristone or the anti-mineralocorticoid spironolactone abolished these effects, but orally administered corticosterone mimicked the ameliorating effects of exercise. Exercise prevented the ischemia-induced expression of mRNA encoding aquaporin 4 (AQP4) and Na(+)/H(+) exchangers (NHEs) (n=5 or 7, P<0.01). Microglia and NG2 glia expressed NHE1 in the peri-ischemic region of rat brains and also in mixed glial cultures. Corticosterone at ~10nM reduced NHE1 and AQP4 expression in mixed glial and pure microglial cultures. Dexamethasone and aldosterone at 10nM did not significantly alter NHE1 and AQP4 expression. Exposure to a NHE inhibitor caused shrinkage of microglial cells. These results suggest that the stressful short-period and slow-paced treadmill exercise suppressed NHE1 and AQP4 expression resulting in the amelioration of brain edema at least partly via the moderate increase in plasma corticosterone levels.

Anti-inflammatory effects of noradrenaline on LPS-treated microglial cells: Suppression of NFκB nuclear translocation and subsequent STAT1 phosphorylation

Noradrenaline (NA) has marked anti-inflammatory effects on activated microglial cells. The present study was conducted to elucidate the mechanisms underlying the NA effects using rat primary cultured microglial cells. NA, an α1 agonist, phenylephrine (Phe) and a β2 agonist, terbutaline (Ter) suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) release by microglia and prevented neuronal degeneration in LPS-treated neuron-microglia coculture. The agents suppressed expression of mRNA encoding proinflammatory mediators. Both an α1-selective blocker terazocine and a β2-selective blocker butoxamine overcame the suppressive effects of NA. cAMP-dependent kinase (PKA) inhibitors did not abolish the suppressive NA effects. LPS decreased IκB leading to NFκB translocation into nuclei, then induced phosphorylation of signal transducer and activator of transcription 1 (STAT1) and expression of interferon regulatory factor 1 (IRF1). NA inhibited LPS-induced these changes. When NFκB expression was knocked down with siRNA, LPS-induced STAT1 phosphorylation and IRF1 expression was abolished. NA did not suppress IL-6 induced STAT1 phosphorylation and IRF1 expression. These results suggest that one of the critical mechanisms underlying the anti-inflammatory effects of NA is the inhibition of NFκB translocation. Although inhibitory effects of NA on STAT1 phosphorylation and IRF1 expression may contribute to the overall suppressive effects of NA, these may be the downstream events of inhibitory effects on NFκB. Since NA, Phe and Ter exerted almost the same effects and PKA inhibitors did not show significant antagonistic effects, the suppression by NA might not be dependent on specific adrenergic receptors and cAMP-dependent signaling pathway.

The ameliorative effects of a hypnotic bromvalerylurea in sepsis

Sepsis is a severe pathologic event, frequently causing death in critically ill patients. However, there are no approved drugs to treat sepsis, despite clinical trials of many agents that have distinct targets. Therefore, a novel effective treatment should be developed based on the pathogenesis of sepsis. We recently observed that an old hypnotic drug, bromvalerylurea (BU) suppressed expression of many kinds of pro- and anti-inflammatory mediators in LPS- or interferon-γ activated alveolar and peritoneal macrophages (AMs and PMs). Taken the anti-inflammatory effects of BU on macrophages, we challenged it to septic rats that had been subjected to cecum-ligation and puncture (CLP). BU was subcutaneously administered to septic rats twice per day. Seven days after CLP treatment, 85% of septic rats administrated vehicle had died, whereas administration of BU reduce the rate to 50%. Septic rats showed symptoms of multi-organ failure; respiratory, circulatory and renal system failures as revealed by histopathological analyses, blood gas test and others. BU ameliorated these symptoms. BU also prevented elevated serum-IL-6 level as well as IL-6 mRNA expression in septic rats. Collectively, BU might be a novel agent to ameliorate sepsis by preventing the onset of MOF.

Zonisamide up-regulated the mRNAs encoding astrocytic anti-oxidative and neurotrophic factors

Zonisamide has been proven as an effective drug for the recovery of degenerating dopaminergic neurons in the animal models of Parkinson's disease. However, several lines of evidence have questioned the neuroprotective capacity of zonisamide in animal models of Parkinson's disease. Although it suppresses dopaminergic neurodegeneration in animal models, the cellular and molecular mechanisms underlying the effectiveness of zonisamide are not fully understood. The current study demonstrates the effects of zonisamide on astrocyte cultures and two 6-hydroxydopamine-induced models of Parkinson's disease. Using primary astrocyte cultures, we showed that zonisamide up-regulated the expression of mRNA encoding mesencephalic astrocyte-derived neurotrophic factor, vascular endothelial growth factor, proliferating cell nuclear antigen, metallothionein-2, copper/zinc superoxide dismutase, and manganese superoxide dismutase. Similar responses to zonisamide were found in substantia nigra where the rats were pre-treated with 6-hydroxydopamine. Notably, pharmacological inhibition of 6-hydroxydopamine-induced toxicity by zonisamide pre-treatment was also confirmed using rat mesencephalic organotypic slice cultures of substantia nigra. In addition to this, zonisamide post-treatment also attenuated the nigral tyrosine hydroxylase-positive neuronal loss induced by 6-hydroxydopamine. Taken together, these studies demonstrate that zonisamide protected dopamine neurons in two Parkinson's disease models through a novel mechanism, namely increasing the expression of some important astrocyte-mediated neurotrophic and anti-oxidative factors.

Comparative Efficacy of Piperazine Citrate, Levamisole and Pineapple Leaves Extract Against Naturally Infected Ascariasis in Indigenous Chickens

The experiment was carried out to determine the comparative efficacy of piperazine citrate, levamisole and pineapple leaves extract as anthelmintics against ascariasis in chicken in the Department of Pharmacology in collaboration with Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh, during the period from July to October 2004. Accordingly forty chickens naturally infected with ascarid parasite were selected for this experiment. The chickens were equally divided into 4 (A, B, C and D) groups. Group A was kept as infected control, while groups B, C and D were treated with piperazine citrate, levamisole and pineapple leaves extract, respectively. Although pineapple leaves extract showed less effectiveness in reducing parasite count in postmortem examination than piperazine citrate and levamisole but its use may be encouraging because of less adverse effects. In all treated groups total erythrocyte count (TEC), hemoglobin estimation (Hb) and packed cell volume (PCV) significantly (p < 0.01) increased and erythrocyte sedimentation rate (ESR) and total leukocyte count (TLC) significantly (p < 0.01) decreased. Body weight was found to be increased following administration of piperazine citrate, levamisole and pineapple leaves extract. Key words: Piperazine citrate, levamisole, pineapple leaves, ascariasis, chicken doi:10.3329/bjvm.v4i1.1521 Bangl. J. Vet. Med. (2006). 4 (1): 27-29

Determination of minimum inhibitory concentration (MIC) of cloxacillin for selected isolates of methicillin-resistant Staphylococcus aureus (MRSA) with their antibiogram

The minimum inhibitory concentration (MIC) represents the concentration of antimicrobial at which there is complete inhibition of growth of organism. In order to determine the MIC of cloxacillin, 10 MRSA were previously detected from 40 clinical isolates of Staphylococcus aureus by polymerase chain reaction (PCR). Agar plate dilution test was used to determine the MIC of cloxacillin. The clinical samples were collected from Mymensingh Medical College Hospital, Mymensingh. The study was done in the Department of Medicine, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh from July 2006 to June 2007. The MIC of the cloxacillin for 5 MRSA strains were ≥32 (mg/ml), for 1 MRSA strain was ≥ 128(mg/ml) and for another 4 MRSA strains were above ≥128 (mg/ml). Antimicrobial susceptibility test of the isolated organisms were done by disc diffusion method. On antibiotic susceptibility test, MRSA strains showed 100% resistant against penicillin, oxacillin, cloxacillin and amoxycillin. Cent per cent susceptibility of MRSA was found against vancomycin, ciprofloxacin, erythromycin, fusidic acid and rifampicin. Key words: Minimum inhibitory concentration (MIC), antibiotic resistance, cloxacillin, methicillin-resistant Staphylococcus aureus (MRSA) DOI = 10.3329/bjvm.v6i1.1350 Bangl. J. Vet. Med. (2008). 6 (1): 121-126