Modulation of NLRP3 inflammasomes activation contributes to improved survival and function of mesenchymal stromal cell spheroids.

Mesenchymal stem cells (MSCs) are ubiquitous multipotent cells that exhibit significant therapeutic potentials in a variety of disorders. Nevertheless, their clinical efficacy is limited owing to poor survival, low rate of engraftment, and impaired potency upon transplantation. Spheroidal three-dimensional (3D) culture of MSCs (MSC3D) has been proven to better preserve their in vivo functional properties. However, the molecular mechanisms underlying the improvement in MSC function by spheroid formation are not clearly understood. NLRP3 inflammasomes, a key component of the innate immune system, have recently been shown to play a role in cell fate decision of MSCs. The present study examined the role of NLRP3 inflammasomes in the survival and potency of MSC spheroids. We found that MSC3D led to decreased activation of NLRP3 inflammasomes through alleviation of ER stress in an autophagy-dependent manner. Importantly, downregulation of NLRP3 inflammasomes signaling critically contributes to the enhanced survival rate in MSC3D through modulation of pyroptosis and apoptosis. The critical role of NLRP3 inflammasome suppression in the enhanced therapeutic efficacy of MSC spheroids was further confirmed in an in vivo mouse model of DSS-induced colitis. These findings suggest that 3D culture confers survival and functional advantages to MSCs by suppressing NLRP3 inflammasome activation.

Suntamide A, a neuroprotective cyclic peptide from Cicadidae Periostracum.

Suntamide A (1), a new cyclic peptide, was isolated from Cicadidae Periostracum. The gross structure of 1 was elucidated by detailed analysis of HRMS and 1D/2D NMR spectra, and the absolute configuration was established by C3 Marfey's method. We extended our study to examine biological activity of 1, and found that 1 protected SH-SY5Y cells against rotenone-induced neurotoxicity. This effect of 1 seemed to be attributed to antioxidant induction and protection of mitochondria from rotenone-caused injury. Along with augmentation of the antioxidant system by 1, there was an evident activation of Nrf2, a transcription factor involved in the activation of the antioxidant system. These results indicate that 1 rescued the cells from rotenone-mediated neurotoxicity by enhancing antioxidant capacity via induction of Nrf2, suggesting that the compound could be used as a therapeutic intervention in neurodegenerative diseases such as Parkinson's disease.

Two new secondary metabolites, saccharochlorines A and B, from a marine bacterium Saccharomonospora sp. KCTC-19160.

Two new chlorinated secondary metabolites, saccharochlorines A and B (1 and 2), were isolated from the saline cultivation of a marine-derived bacterium Saccharomonospora sp. (KCTC-19160). The chemical structures of the saccharochlorines were elucidated by 2D NMR and MS spectroscopic data. Saccharochlorines A and B (1 and 2) exhibit weak inhibition of ß-secretase (BACE1) in biochemical inhibitory assay, but they induced the release of Aß (1-40) and Aß (1-42) in H4-APP neuroglial cells. This discrepancy might be derived from the differences between the cellular and sub-cellular environments or the epigenetic stimulation of BACE1 expression.

(E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) Phenol Ameliorates MPTP-Induced Dopaminergic Neurodegeneration by Inhibiting the STAT3 Pathway.

Neuroinflammation is implicated in dopaminergic neurodegeneration. We have previously demonstrated that (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP), a selective signal transducer and activator of transcription 3 (STAT3) inhibitor, has anti-inflammatory properties in several inflammatory disease models. We investigated whether MMPP could protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic cell loss and behavioral impairment. Imprinting control region (ICR) mice (8 weeks old, n = 10 per group) were administered MMPP (5 mg/kg) in drinking water for 1 month, and injected with MPTP (15 mg/kg, four times with 2 h intervals) during the last 7 days of treatment. MMPP decreased MPTP-induced behavioral impairments in rotarod, pole, and gait tests. We also showed that MMPP ameliorated dopamine depletion in the striatum and inflammatory marker elevation in primary cultured neurons by high-performance liquid chromatography and immunohistochemical analysis. Increased activation of STAT3, p38, and monoamine oxidase B (MAO-B) were observed in the substantia nigra and striatum after MPTP injection, effects that were attenuated by MMPP treatment. Furthermore, MMPP inhibited STAT3 activity and expression of neuroinflammatory proteins, including ionized calcium binding adaptor molecule 1 (Iba1), inducible nitric oxide synthase (iNOS), and glial fibrillary acidic protein (GFAP) in 1-methyl-4-phenylpyridinium (MPP+; 0.5 mM)-treated primary cultured cells. However, mitogen-activated protein kinase (MAPK) inhibitors augmented the activity of MMPP. Collectively, our results suggest that MMPP may be an anti-inflammatory agent that attenuates dopaminergic neurodegeneration and neuroinflammation through MAO-B and MAPK pathway-dependent inhibition of STAT3 activation.

Estrogen deficiency exacerbates Aß-induced memory impairment through enhancement of neuroinflammation, amyloidogenesis and NF-ĸB activation in ovariectomized mice.

Estrogen is well known to have a preventative effect in Alzheimer's disease (AD) pathology. Several studies have demonstrated that nuclear factor kappa-B (NF-ĸB) can contribute to the effects of estrogen on the development of AD. We investigated whether NF-ĸB affects amyloid-beta (Aß)-induced memory impairment in an estrogen-lacking condition. In the present study, nine-week-old Institute cancer research (ICR) mice were ovariectomized to block estrogen stimulation. Ten weeks after the ovariectomization, mice were administered with Aß (300 pmol) via intracerebroventricular (ICV) infusion for 2 weeks. Memory impairment, neuroinflammatory protein expression, and amyloidogenic pathways were then measured. Ovariectomized mice demonstrated severe memory impairment, Aß accumulation, neprilysin downregulation, and activation of NF-ĸB signaling compared to sham-control mice. In vitro experiments demonstrated that ß-estradiol (10 µM) inhibited Aß (1 µM)-induced neuroinflammation in microglial BV-2 cells and prevented Aß-induced cell death in primary cultured neuronal cells. As in in vivo experiments, NF-ĸB activation was significantly upregulated in in vitro experiments. Furthermore ß-estradiol treatment inhibited NF-ĸB activation in both of microglial BV-2 cells and cultured neuronal cells. These findings suggest that estrogen may protect against memory impairment through the regulation of Aß accumulation and neurogenic inflammation by inhibiting NF-κB activity.

Lodopyridones B and C from a marine sediment-derived bacterium Saccharomonospora sp.

HPLC-UV guided isolation of the culture broth of a marine bacterium Saccharomonospora sp. CNQ-490 has led to the isolation of two new natural products, lodopyridones B and C (1 and 2) along with the previously reported lodopyridone A (3). Their chemical structures were established from the interpretation of 2D NMR spectroscopic data and the comparison of NMR data with the lodopyridone A (3). Lodopyridones B and C (1 and 2) possess the thiazole, and chloroquinoline groups which are characteristic features of these molecules. Lodopyridones A-C show weak inhibitory activities on the ß-site amyloid precursor protein cleaving enzyme 1 (BACE1).

Globular Adiponectin Inhibits Lipopolysaccharide-Primed Inflammasomes Activation in Macrophages via Autophagy Induction: The Critical Role of AMPK Signaling.

The inflammasome acts as a key platform for the activation of pro-inflammatory cytokines. Adiponectin exhibits potent anti-inflammatory properties. However, the effect of adiponectin on the modulation of the inflammasome has not been explored. Herein, we show that globular adiponectin (gAcrp) suppressed lipopolysaccharide (LPS)-primed inflammasomes activation in murine peritoneal macrophages judged by prevention of interleukin-1ß (IL-1ß) maturation, caspase-1 activation, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) speck formation, and pyroptotic cell death. Interestingly, pretreatment with 3-methyl adenine, a pharmacological inhibitor of autophagy, abrogated the suppressive effects of gAcrp on IL-1ß secretion and caspase-1 activation, indicating the crucial role of autophagy induction in gAcrp-modulation of the inflammasome activation. In addition, inhibition of 5'Adenosine monophaspahate (AMP)-activated protein kinase (AMPK) signaling abolished suppressive effect of gAcrp on inflammasomes activation. Furthermore, autophagy induction or inhibition of the inflammasome activation by gAcrp was not observed in macrophages deficient in AMPK. Taken together, these results indicate that adiponectin inhibits LPS-primed inflammasomes activation in macrophages via autophagy induction and AMPK signaling-dependent mechanisms.

Inhibition of p38 pathway-dependent MPTP-induced dopaminergic neurodegeneration in estrogen receptor alpha knockout mice.

Approximately, 7-10 million people in the world suffer from Parkinson's disease (PD). Recently, increasing evidence has suggested the protective effect of estrogens against nigrostriatal dopaminergic damage in PD. In this study, we investigated whether estrogen affects 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced behavioral impairment in estrogen receptor alpha (ERα)-deficient mice. MPTP (15mg/kg, four times with 1.5-h interval)-induced dopaminergic neurodegeneration was evaluated in ERα wild-type (WT) and knockout (KO) mice. Larger dopamine depletion, behavioral impairments (Rotarod test, Pole test, and Gait test), activation of microglia and astrocytes, and neuroinflammation after MPTP injection were observed in ERα KO mice compared to those in WT mice. Immunostaining for tyrosine hydroxylase (TH) after MPTP injection showed fewer TH-positive neurons in ERα KO mice than WT mice. Levels of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC, metabolite of dopamine) were also lowered in ERα KO mice after MPTP injection. Interestingly, a higher immunoreactivity for monoamine oxidase (MAO) B was found in the substantia nigra and striatum of ERα KO mice after MPTP injection. We also found an increased activation of p38 kinase (which positively regulates MAO B expression) in ERα KO mice. In vitro estrogen treatment inhibited neuroinflammation in 1-methyl-4-phenyl pyridium (MPP+)-treated cultured astrocyte cells; however, these inhibitory effects were removed by p38 inhibitor. These results indicate that ERα might be important for dopaminergic neuronal survival through inhibition of p38 pathway.

CCR5 knockout mice with C57BL6 background are resistant to acetaminophen-mediated hepatotoxicity due to decreased macrophages migration into the liver.

Overdose of acetaminophen (APAP) causes necrosis of centrilobular cells of the liver. Accumulating evidence suggests that innate immune system may contribute to APAP-induced hepatotoxicity. Interaction between RANTES and its receptor C-C chemokine receptor (CCR) 5 is related to recruitment of macrophages to sites of inflammation. In this study, we examined effects of CCR5 deficiency on APAP-mediated liver injury by employing CCR5 knockout (KO) mice. CCR5 wild-type (WT) and KO mice received intraperitoneal injection of APAP (300 mg/kg) and were killed 24 h after the injection. Hepatic injury was determined by using histological and biochemical analyses. Intraperitoneal APAP caused the hepatocytic necrosis, as evidenced by hematoxylin and eosin staining and an increase in alanine transaminase and aspartate transaminase levels in serum. Hepatic damage appeared to be larger in CCR5 WT animals compared with KO animals. There were no differences in cytochrome P450 2E1 between CCR5 WT and KO animals suggesting that the resistance of CCR5 KO mice did not come from alterations in APAP metabolism. Infiltration of macrophages into the liver was reduced in CCR5 KO mice, and this was accompanied decreased inflammatory responses. Inhibition of macrophage activity by pretreatment of gadolinium chloride significantly blocked APAP-caused hepatotoxicity. These results indicate that recruitment of macrophage into the inflammatory sites significantly contributes to APAP-mediated hepatocytic death and CCR5 gene deletion protects from APAP-induced liver injury by alleviating macrophage recruitment and inflammatory responses. This study represents a critical role of CCR5 in macrophage infiltration into the liver and subsequent hepatotoxicity upon challenge of APAP.

Inhibitory effect of ent-Sauchinone on amyloidogenesis via inhibition of STAT3-mediated NF-κB activation in cultured astrocytes and microglial BV-2 cells.

BACKGROUND: ent-Sauchinone is a polyphenolic compound found in plants belonging to the lignan family. ent-Sauchinone has been shown to modulate the expression of inflammatory factors through the nuclear factor-kappa B (NF-κB) signaling pathway. It is well known that neuroinflammation is associated with amyloidogenesis. Thus, in the present study, we investigated whether ent-Sauchinone could have anti-amyloidogenic effects through the inhibition of NF-κB pathways via its anti-inflammatory property. METHODS: To investigate the potential effect of ent-Sauchinone on anti-neuroinflammation and anti-amyloidogenesis in in vitro studies, we used microglial BV-2 cells and cultured astrocytes treated with ent-Sauchinone (1, 5, and 10 µM) for 24 hours. For the detection of anti-neuro-inflammatory responses, reative oxygen species (ROS) and Nitric oxide (NO) generation and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were measured with assay kits and western blotting. ß-secretase and ß-secretase activities and ß-amyloid levels were determined for measuring the anti-amyloidogenic effects of ent-Sauchinone by enzyme assay kits. NF-κB and STAT3 signals were detected with electromobility shift assay (EMSA) to study the related signaling pathways. The binding of ent-Sauchinone to STAT3 was evaluated by a pull-down assay and by a docking model using Autodock VINA software (Hoover's Inc., Texas, United states). RESULTS: ent-Sauchinone (1, 5, and 10 µM) effectively decreased lipopolysaccharide (LPS)-(1 µg/ml) induced inflammatory responses through the reduction of ROS and NO generations and iNOS and COX-2 expressions in cultured astrocytes and microglial BV-2 cells. ent-Sauchinone also inhibited LPS-induced amyloidogenesis through the inhibition of ß-secretase and ß-secretase activity. NF- κB amyloid and STAT3, critical transcriptional factors regulating not only inflammation but also amyloidogenesis, were also inhibited in a concentration dependent manner by ent-Sauchinone by blocking the phosphorylation of I κB and STAT3 in cultured astrocytes and microglial BV-2 cells. The docking model approach showed that ent-Sauchinone binds to STAT3, and the employment of a STAT3 inhibitor and siRNA reversed ent-Sauchinone-induced inhibition NF-κB activation and Aß generation. CONCLUSIONS: These results indicated that ent-Sauchinone inhibited neuroinflammation and amyloidogenesis through the inhibition of STAT3-mediated NF-κB activity, and thus could be applied in the treatment of neuro-inflammatory diseases, including Alzheimer's disease.

Lack of CCR5 modifies glial phenotypes and population of the nigral dopaminergic neurons, but not MPTP-induced dopaminergic neurodegeneration.

Constitutive expression of C-C chemokine receptor (CCR) 5 has been detected in astrocytes, microglia and neurons, but its physiological roles in the central nervous system are obscure. The bidirectional interactions between neuron and glial cells through CCR5 and its ligands were thought to be crucial for maintaining normal neuronal activities. No study has described function of CCR5 in the dopaminergic neurodegeneration in Parkinson's disease. In order to examine effects of CCR5 on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurodegeneration, we employed CCR5 wild type (WT) and knockout (KO) mice. Immunostainings for tyrosine hydroxylase (TH) exhibited that CCR5 KO mice had lower number of TH-positive neurons even in the absence of MPTP. Difference in MPTP (15mg/kg×4 times, 2hr interval)-mediated loss of TH-positive neurons was subtle between CCR5 WT and KO mice, but there was larger dopamine depletion, behavioral impairments and microglial activation in CCR5 deficient mice. Intriguingly, CCR5 KO brains contained higher immunoreactivity for monoamine oxidase (MAO) B which was mainly localized within astrocytes. In agreement with upregulation of MAO B, concentration of MPP+ was higher in the substantia nigra and striatum of CCR5 KO mice after MPTP injection. We found remarkable activation of p38 MAPK in CCR5 deficient mice, which positively regulates MAO B expression. These results indicate that CCR5 deficiency modifies the nigrostriatal dopaminergic neuronal system and bidirectional interaction between neurons and glial cells via CCR5 might be important for dopaminergic neuronal survival.

Anti-inflammatory and anti-amyloidogenic effects of a small molecule, 2,4-bis(p-hydroxyphenyl)-2-butenal in Tg2576 Alzheimer's disease mice model.

BACKGROUND: Alzheimer's disease (AD) is pathologically characterized by excessive accumulation of amyloid-beta (Aß) fibrils within the brain and activation of astrocytes and microglial cells. In this study, we examined anti-inflammatory and anti-amyloidogenic effects of 2,4-bis(p-hydroxyphenyl)-2-butenal (HPB242), an anti-inflammatory compound produced by the tyrosine-fructose Maillard reaction. METHODS: 12-month-old Tg2576 mice were treated with HPB242 (5 mg/kg) for 1 month and then cognitive function was assessed by the Morris water maze test and passive avoidance test. In addition, western blot analysis, Gel electromobility shift assay, immunostaining, immunofluorescence staining, ELISA and enzyme activity assays were used to examine the degree of Aß deposition in the brains of Tg2576 mice. The Morris water maze task was analyzed using two-way ANOVA with repeated measures. Otherwise were analyzed by one-way ANOVA followed by Dunnett's post hoc test. RESULTS: Treatment of HPB242 (5 mg/kg for 1 month) significantly attenuated cognitive impairments in Tg2576 transgenic mice. HPB242 also prevented amyloidogenesis in Tg2576 transgenic mice brains. This can be evidenced by Aß accumulation, BACE1, APP and C99 expression and ß-secretase activity. In addition, HPB242 suppresses the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as activation of astrocytes and microglial cells. Furthermore, activation of nuclear factor-kappaB (NF-κB) and signal transducer and activator of transcription 1/3 (STAT1/3) in the brain was potently inhibited by HPB242. CONCLUSIONS: Thus, these results suggest that HPB242 might be useful to intervene in development or progression of neurodegeneration in AD through its anti-inflammatory and anti-amyloidogenic effects.

Ethanol extract of Magnolia officinalis prevents lipopolysaccharide-induced memory deficiency via its antineuroinflammatory and antiamyloidogenic effects.

Magnolia bark contains several compounds such as magnolol, honokiol, 4-O-methylhonokiol, obovatol, and other neolignan compounds. These compounds have been reported to have various beneficial effects in various diseases. There is sufficient possibility that ethanol extract of Magnolia officinalis is more effective in amyloidogenesis via synergism of these ingredients. Neuroinflammation has been known to play a critical role in the pathogenesis of Alzheimer's disease (AD). We investigated whether the ethanol extract of M. officinalis (10 mg/ kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis in AD mouse model by intraperitoneal lipopolysaccharide (LPS, 250 µg/ kg/day for seven times) injection. We found that ethanol extract of M. officinalis prevented LPS-induced memory deficiency as well as inhibited the LPS-induced elevation of inflammatory proteins, such as inducible nitric oxide synthase and cyclooxygenase 2, and activation of astrocytes and microglia. In particular, administration of M. officinalis ethanol extract inhibited LPS-induced amyloidogenesis, which resulted in the inhibition of amyloid precursor protein, beta-site amyloid-precursor-protein-cleaving enzyme 1 and C99. Thus, this study shows that ethanol extract of M. officinalis prevents LPS-induced memory impairment as well as amyloidogenesis via inhibition of neuroinflammation and suggests that ethanol extract of M. officinalis might be a useful intervention for neuroinflammation-associated diseases such as AD.

Dopaminergic neuroprotective effects of inosine in MPTP-induced parkinsonian mice via brain-derived neurotrophic factor upregulation.

Parkinson's disease (PD) is the second most common neurodegenerative disease. However, no curative or modifying therapy is known. Inosine is a purine nucleoside that increases brain-derived neurotrophic factor (BDNF) expression in the brain through adenosine receptors. Herein, we investigated the neuroprotective effects of inosine and elucidated the mechanisms underlying its pharmacological action. Inosine rescued SH-SY5Y neuroblastoma cells from MPP+ injury in a dose-dependent manner. Inosine protection correlated with BDNF expression and the activation of its downstream signaling cascade, as the TrkB receptor inhibitor, K252a and siRNA against the BDNF gene remarkably reduced the protective effects of inosine. Blocking the A1 or A2A adenosine receptors diminished BDNF induction and the rescuing effect of inosine, indicating a critical role of adenosine A1 and A2A receptors in inosine-related BDNF elevation. We assessed whether the compound could protect dopaminergic neurons from MPTP-induced neuronal injury. Beam-walking and challenge beam tests revealed that inosine pretreatment for 3 weeks reduced the MPTP-induced motor function impairment. Inosine ameliorated dopaminergic neuronal loss and MPTP-mediated astrocytic and microglial activation in the substantia nigra and striatum. Inosine ameliorated the depletion of striatal dopamine and its metabolite following MPTP injection. BDNF upregulation and the activation of its downstream signaling pathway seemingly correlate with the neuroprotective effects of inosine. To our knowledge, this is the first study to demonstrate the neuroprotective effects of inosine against MPTP neurotoxicity via BDNF upregulation. These findings highlight the therapeutic potential of inosine in dopaminergic neurodegeneration in PD brains.

Intermittent fasting protects the nigral dopaminergic neurons from MPTP-mediated dopaminergic neuronal injury in mice.

Dietary restriction through low-calorie intake or intermittent fasting benefits many organs, including the brain. This study investigated the neuroprotective effects of fasting in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. We found that fasting every other day rather than weekly increased the levels of brain-derived neurotrophic factor and glial-derived neurotrophic factor in the nigrostriatal pathway. Therefore, we maintained the animals on alternate-day fasting for 2 weeks and injected MPTP (30 mg/kg/day, intraperitoneally [i.p.]) for five days. We observed that alternate-day fasting attenuated MPTP-induced dopaminergic neuronal loss and astroglial activation in the substantia nigra and the striatum. Moreover, neurochemical analysis using high-performance liquid chromatography showed that alternate-day fasting reduced MPTP-induced depletion of striatal dopamine. Consistent with these results, behavioral tests showed that fasting suppressed the motor impairment caused by MPTP. Furthermore, fasting increased the phosphorylation of phosphatidylinositol-3-kinase and protein kinase B, which are downstream signaling molecules of neurotrophic factors. Fasting also increased the phosphorylation of extracellular signal-regulated protein kinase and cAMP response element-binding protein, further supporting the involvement of neurotrophic factors in the observed neuroprotective effects. Hence, our results demonstrated the dopaminergic neuroprotection of intermittent fasting in an MPTP mouse model of Parkinson's disease, supporting the idea that fasting could be an instrumental tool for preventing neurodegeneration in the brain.

Deficiency of C-C chemokine receptor 5 suppresses tumor development via inactivation of NF-κB and inhibition of monocyte chemoattractant protein-1 in urethane-induced lung tumor model.

To evaluate the significance of C-C chemokine receptor type 5 (CCR5) in lung tumor development, we compared carcinogen-induced tumor growth in CCR5 knockout (CCR5(-/-)) mice and wild-type (CCR5(+/+)) mice. CCR5(-/-) mice showed reduced urethane (1g/kg)-induced tumor incidence when compared with those of CCR5(+/+) mice. We investigated the activation of nuclear factor-kappaB/STAT3 since these are implicated transcription factors in the regulation of genes involving tumor growth. Significant inhibition of DNA-binding activity of nuclear factor-kappaB and STAT3, and the translocation of p50 and p65 into the nucleus and the phosphorylation of IĸB were found in the lungs of CCR5(-/-) mice compared with the lungs of CCR5(+/+) mice. Expression of apoptotic protein such as cleaved caspase-3, cleaved PARP and Bax was elevated, whereas the expression levels of survival protein such as Bcl-2 and cIAP1 was decreased in the lungs of CCR5(-/-) mice. Interestingly, we found that the level of monocyte chemoattractant protein-1 (MCP-1), a tumor growth-promoting cytokine, was significantly reduced in the lung tumor tissue and blood of CCR5(-/-) mice compared with the level in CCR5(+/+) mice. In addition, CCR5 small interfering RNA (siRNA) and inhibitor of MCP-1 blocked lung cancer cell growth, which was abolished by the addition of MCP-1 protein in cultured lung cancer cells. Moreover, inactivation of CD8(+) cytotoxic T cell and dendritic cells was significantly increased in the blood, lung tumors and spleens of CCR5(-/-) mice compared with that of CCR5(+/+) mice. Therefore, these results showed that CCR5 deficiency suppressed lung tumor development through the inhibition of nuclear factor-kappaB/STAT3 pathways and the downregulation of MCP-1 in the carcinogen-induced lung tumor model.

Obovatol improves cognitive functions in animal models for Alzheimer's disease.

Etiology of Alzheimer's disease (AD) is obscure, but neuroinflammation and accumulation of ß-amyloid (Aß) are implicated in pathogenesis of AD. We have shown anti-inflammatory and neurotrophic properties of obovatol, a biphenolic compound isolated from Magnolia obovata. In this study, we examined the effect of obovatol on cognitive deficits in two separate AD models: (i) mice that received intracerebroventricular (i.c.v.) infusion of Aß(1-42) (2.0 µg/mouse) and (ii) Tg2576 mice-expressing mutant human amyloid precursor protein (K670N, M671L). Injection of Aß(1-42) into lateral ventricle caused memory impairments in the Morris water maze and passive avoidance tasks, being associated with neuroinflammation. Aß(1-42) -induced abnormality was significantly attenuated by administration of obovatol. When we analyzed with Tg2576 mice, long-term treatment of obovatol (1 mg/kg/day for 3 months) significantly improved cognitive function. In parallel with the improvement, treatment suppressed astroglial activation, BACE1 expression and NF-κB activity in the transgenic mice. Furthermore, obovatol potently inhibited fibrillation of Aßin vitro in a dose-dependent manner, as determined by Thioflavin T fluorescence and electron microscopic analysis. In conclusion, our data demonstrated that obovatol prevented memory impairments in experimental AD models, which could be attributable to amelioration of neuroinflammation and amyloidogenesis by inhibition of NF-κB signaling pathway and anti-fibrillogenic activity of obovatol.

Inhibitory effect of 4-O-methylhonokiol on lipopolysaccharide-induced neuroinflammation, amyloidogenesis and memory impairment via inhibition of nuclear factor-kappaB in vitro and in vivo models.

BACKGROUND: Neuroinflammation is important in the pathogenesis and progression of Alzheimer disease (AD). Previously, we demonstrated that lipopolysaccharide (LPS)-induced neuroinflammation caused memory impairments. In the present study, we investigated the possible preventive effects of 4-O-methylhonokiol, a constituent of Magnolia officinalis, on memory deficiency caused by LPS, along with the underlying mechanisms. METHODS: We investigated whether 4-O-methylhonokiol (0.5 and 1 mg/kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis on AD model mice by intraperitoneal LPS (250 µg/kg daily 7 times) injection. In addition, LPS-treated cultured astrocytes and microglial BV-2 cells were investigated for anti-neuroinflammatory and anti-amyloidogenic effect of 4-O-methylhonkiol (0.5, 1 and 2 µM). RESULTS: Oral administration of 4-O-methylhonokiol ameliorated LPS-induced memory impairment in a dose-dependent manner. In addition, 4-O-methylhonokiol prevented the LPS-induced expression of inflammatory proteins; inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as activation of astrocytes (expression of glial fibrillary acidic protein; GFAP) in the brain. In in vitro study, we also found that 4-O-methylhonokiol suppressed the expression of iNOS and COX-2 as well as the production of reactive oxygen species, nitric oxide, prostaglandin E2, tumor necrosis factor-α, and interleukin-1ß in the LPS-stimulated cultured astrocytes. 4-O-methylhonokiol also inhibited transcriptional and DNA binding activity of NF-κB via inhibition of IκB degradation as well as p50 and p65 translocation into nucleus of the brain and cultured astrocytes. Consistent with the inhibitory effect on neuroinflammation, 4-O-methylhonokiol inhibited LPS-induced Aß1-42 generation, ß- and γ-secretase activities, and expression of amyloid precursor protein (APP), BACE1 and C99 as well as activation of astrocytes and neuronal cell death in the brain, in cultured astrocytes and in microglial BV-2 cells. CONCLUSION: These results suggest that 4-O-methylhonokiol inhibits LPS-induced amyloidogenesis via anti-inflammatory mechanisms. Thus, 4-O-methylhonokiol can be a useful agent against neuroinflammation-associated development or the progression of AD.

Inhibition of extracellular signal-regulated kinase activity improves cognitive function in Tg2576 mice.

1. Deposition of ß-amyloid (Aß) peptide is a defining pathological hallmark of Alzheimer's disease (AD) and is involved in memory impairment. Evidence suggests that activation of an extracellular signal-regulated kinase (ERK) pathway is related to Aß accumulation. Thus, the aim of the present study was to investigate the effects of an ERK inhibitor (U0126) on amyloidogenesis and cognitive function in Tg2576 mice. 2. Tg2576 mice were injected with U0126 (20 mg/kg, i.p.) or vehicle (1% dimethyl sulphoxide in sterile saline) once a day for 7 days and then cognitive function was assessed by the Morris water maze test and passive avoidance test. In addition, immunostaining, western blot analysis, ELISA and enzyme activity assays were used to examine the degree of Aß deposition in the brains of Tg2576 mice. 3. Our results showed that U0126 attenuated memory impairment and inhibited Aß deposition in the brains of Tg2576 mice. Further experiments revealed that the inhibition of Aß deposition by U0126 was due to a reduction in ß-secretase and amyloid precursor protein expression in the brains of U0126-treated Tg2576 mice. 4. These results suggest that the ERK pathway is associated with Aß accumulation and consequent memory dysfunction in Tg2576 mice and that inhibition of the ERK pathway may be an appropriate intervention in the treatment of AD.

Inhibitory effect of ethanol extract of Magnolia officinalis on memory impairment and amyloidogenesis in a transgenic mouse model of Alzheimer's disease via regulating ß-secretase activity.

Alzheimer's disease (AD) is the most common form of dementia and is characterized by deposition of amyloid beta (Aß) in the brain. The components of the herb Magnolia officinalis are known to have antiinflammatory, antioxidative and neuroprotective activities. In this study we investigated the effects of ethanol extract of M. officinalis on memory dysfunction and amyloidogenesis in a transgenic mouse model of AD. Oral pretreatment of ethanol extract of M. officinalis (10 mg/kg in 0.05% ethanol) into drinking water for 3 months inhibited memory impairment and Aß deposition in the brain of Tg2576 mice. Ethanol extract of M. officinalis also decreased activity of ß-secretase, cleaving Aß from amyloid precursor protein (APP), and expression of ß-site APP cleaving enzyme 1 (BACE1), APP and its product, C99. Our results showed that ethanol extract of M. officinalis effectively prevented memory impairment via down-regulating ß-secretase activity.