Tauroursodeoxycholic acid (TUDCA) is neuroprotective in a chronic mouse model of Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a progressive motor disease of unknown etiology. Although neuroprotective ability of endogenous bile acid, tauroursodeoxycholic acid (TUDCA), shown in various diseases, including an acute model of PD,the potential therapeutic role of TUDCA in progressive models of PD that exhibit all aspects of PD has not been elucidated. In the present study, mice were assigned to one of four treatment groups: (1) Probenecid (PROB); (2) TUDCA, (3) MPTP + PROB (MPTPp); and (3) TUDCA + MPTPp. Methods: Markers for dopaminergic function, neuroinflammation, oxidative stress and autophagy were assessed using high performance liquid chromatography (HPLC), immunohistochemistry (IHC) and western blot (WB) methods. Locomotion was measured before and after treatments. Results: MPTPp decreased the expression of dopamine transporters (DAT) and tyrosine hydroxylase (TH), indicating dopaminergic damage, and induced microglial and astroglial activation as demonstrated by IHC analysis. MPTPp also decreased DA and its metabolites as demonstrated by HPLC analysis. Further, MPTPp-induced protein oxidation; increased LAMP-1 expression indicated autophagy and the promotion of alpha-synuclein (α-SYN) aggregation. Discussion: Pretreatment with TUDCA protected against dopaminergic neuronal damage, prevented the microglial and astroglial activation, as well as the DA and DOPAC reductions caused by MPTPp. TUDCA by itself did not produce any significant change, with data similar to the negative control group. Pretreatment with TUDCA prevented protein oxidation and autophagy, in addition to inhibiting α-SYN aggregation. Although TUDCA pretreatment did not significantly affect locomotion, only acute treatment effects were measured, indicating more extensive assessments may be necessary to reveal potential therapeutic effects on behavior. Together, these results suggest that autophagy may be involved in the progression of PD and that TUDCA may attenuate these effects. The efficacy of TUDCA as a novel therapy in patients with PD clearly warrants further study.

Neuronal Aquaporin 1 Inhibits Amyloidogenesis by Suppressing the Interaction Between Beta-Secretase and Amyloid Precursor Protein.

The accumulation of amyloid-ß (Aß) is a characteristic event in the pathogenesis of Alzheimer's disease (AD). Aquaporin 1 (AQP1) is a membrane water channel protein belonging to the AQP family. AQP1 levels are elevated in the cerebral cortex during the early stages of AD, but the role of AQP1 in AD pathogenesis is unclear. We first determined the expression and distribution of AQP1 in brain tissue samples of AD patients and two AD mouse models (3xTg-AD and 5xFAD). AQP1 accumulation was observed in vulnerable neurons in the cerebral cortex of AD patients, and in neurons affected by the Aß or tau pathology in the 3xTg-AD and 5xFAD mice. AQP1 levels increased in neurons as aging progressed in the AD mouse models. Stress stimuli increased AQP1 in primary cortical neurons. In response to cellular stress, AQP1 appeared to translocate to endocytic compartments of ß- and γ-secretase activities. Ectopic expression of AQP1 in human neuroblastoma cells overexpressing amyloid precussir protein (APP) with the Swedish mutations reduced ß-secretase (BACE1)-mediated cleavage of APP and reduced Aß production without altering the nonamyloidogenic pathway. Conversely, knockdown of AQP1 enhanced BACE1 activity and Aß production. Immunoprecipitation experiments showed that AQP1 decreased the association of BACE1 with APP. Analysis of a human database showed that the amount of Aß decreases as the expression of AQP1 increases. These results suggest that the upregulation of AQP1 is an adaptive response of neurons to stress that reduces Aß production by inhibiting the binding between BACE1 and APP.

Identification of altered microRNAs in serum of a mouse model of Parkinson's disease.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease, whose hallmark is the loss of dopamine terminals in the substantia nigra pars compacta (SNpc). PD is usually diagnosed after the appearance of motor symptoms, when about 70% of neurons in the SNpc have already been lost. Because of that, it is important to search for new methods that aid in the early diagnosis of PD. In recent years, microRNAs (miRs) have emerged as potential biomarkers for a variety of diseases and hold the potential to be used to aid in the diagnosis of PD. Therefore, the aim of this study was to characterize if specific miRs are differentially expressed in serum in a mouse model of PD. To induce PD-like damage, mice were subcutaneously injected with 25 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) by administering 10 doses over a period of 5 weeks, with 3.5 days between doses. Expression of 71 different microRNAs was quantified in serum separated from blood collected at day 35, using next-generation sequencing. Histological analysis and quantification of neurotransmitters were performed to confirm dopaminergic neurodegeneration. Chronic MPTP treatment induced loss of dopaminergic terminals in the SNpc and caudate putamen, confirmed by a decrease in the number of tyrosine hydroxylase and dopamine transporter positive cells. In addition, MPTP decreased the concentration of dopamine and its metabolites in the SNpc, simulating the damage observed in PD. From the 71 miRs analyzed, only 4 were differentially expressed after MPTP treatment. Serum levels of miR19b, miR124, miR126a and miR133b were significantly decreased in MPTP-treated mice compared to control. These data suggest that specific miRs are downregulated in a pre-clinical model of PD and hold the potential to be used as biomarkers to aid in the diagnosis of this disease. Further experiments need to be conducted to validate the use of these miRs as biomarkers of PD in additional pre-clinical models as well as in samples from patients diagnosed with PD.

Combination Therapy with Low-Dose IVIG and a C1-esterase Inhibitor Ameliorates Brain Damage and Functional Deficits in Experimental Ischemic Stroke.

Acute ischemic stroke causes a high rate of deaths and permanent neurological deficits in survivors. Current interventional treatment, in the form of enzymatic thrombolysis, benefits only a small percentage of patients. Brain ischemia triggers mobilization of innate immunity, specifically the complement system and Toll-like receptors (TLRs), ultimately leading to an exaggerated inflammatory response. Here we demonstrate that intravenous immunoglobulin (IVIG), a scavenger of potentially harmful complement fragments, and C1-esterase inhibitor (C1-INH), an inhibitor of complement activation, exert a beneficial effect on the outcome of experimental brain ischemia (I) and reperfusion (R) injury induced by transient occlusion of middle cerebral artery in mice. Both IVIG and C1-INH significantly and in a dose-responsive manner reduced brain infarction size, neurological deficit and mortality when administered to male mice 30 min before ischemia or up to 6 h after the onset of reperfusion. When combined, suboptimal doses of IVIG and C1-INH potentiated each other's neuroprotective therapeutic effects. Complement C3 and TLR2 signals were colocalized and significantly greater in brain cells adjacent to infracted brain lesions when compared to the corresponding regions of the contralateral hemisphere and to control (sham) mice. Treatment with IVIG and C1-INH effectively reduced deposition of C3b and downregulated excessive TLR2 and p-JNK1 expression at the site of I/R injury. Taken together, these results provide a rationale for potential use of IVIG and C1-INH, alone or in combination with ischemic stroke and other neurological conditions that involve inappropriately activated components of the innate immune system.

The role of adiponectin in obesity-associated female-specific carcinogenesis.

Adipose tissue is a highly vascularized endocrine organ, and its secretion profiles may vary with obesity. Adiponectin is secreted by adipocytes that make up adipose tissue. Worldwide, obesity has been designated a serious health problem among women and is associated with a variety of metabolic disorders and an increased risk of developing cancer of the cervix, ovaries, uterus (uterine/endometrial), and breast. In this review, the potential link between obesity and female-specific malignancies is comprehensively presented by discussing significant features of the intriguing and complex molecule, adiponectin, with a focus on recent findings highlighting its molecular mechanism of action in female-specific carcinogenesis.

Combination therapy with lenalidomide and nanoceria ameliorates CNS autoimmunity.

OBJECTIVE: Multiple sclerosis (MS) is a debilitating neurological disorder involving an autoimmune reaction to oligodendrocytes and degeneration of the axons they ensheath in the CNS. Because the damage to oligodendrocytes and axons involves local inflammation and associated oxidative stress, we tested the therapeutic efficacy of combined treatment with a potent anti-inflammatory thalidomide analog (lenalidomide) and novel synthetic anti-oxidant cerium oxide nanoparticles (nanoceria) in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. METHODS: C57BL/6 mice were randomly assigned to a control (no EAE) group, or one of the four myelin oligodendrocyte glycoprotein-induced EAE groups: vehicle, lenalidomide, nanoceria, or lenalidomide plus nanoceria. During a 23 day period, clinical EAE symptoms were evaluated daily, and MRI brain scans were performed at 11-13 days and 20-22 days. Histological and biochemical analyses of brain tissue samples were performed to quantify myelin loss and local inflammation. RESULTS: Lenalidomide treatment alone delayed symptom onset, while nanoceria treatment had no effect on symptom onset or severity, but did promote recovery; lenalidomide and nanoceria each significantly attenuated white matter pathology and associated inflammation. Combined treatment with lenalidomide and nanoceria resulted in a near elimination of EAE symptoms, and reduced white matter pathology and inflammatory cell responses to a much greater extent than either treatment alone. INTERPRETATION: By suppressing inflammation and oxidative stress, combined treatment with lenalidomide and nanoceria can reduce demyelination and associated neurological symptoms in EAE mice. Our preclinical data suggest a potential application of this combination therapy in MS.

The use of MRI to assist the section selections for classical pathology assessment of neurotoxicity.

MRI was utilized to probe T2 changes in living brain following exposure of rats to one of ten classical neurotoxicants. Brains were subsequently perfused for classical neuropathology examination. This approach was predicated on the assumption that the T2 changes represent loci of neurotoxicity encompassing those seen using neuropathology techniques. The traditional neurotoxicologic approach of selecting a few arbitrary brain sections is dramatically improved by MRI targeting that can indicate the location(s) at which to collect "smart sections" for subsequent workup. MRI scans can provide the equivalent of 64 coronal sections; the number estimated for full coverage of the rat brain if only traditional neuropathology is utilized. Use of MRI allows each animal to serve as its own control as well as longitudinal observations of the life cycle of the neurotoxic lesion(s) (inception, apex and regression). Optimization of time of sacrifice and selection of an appropriate stain based on MRI-identified brain areas could be greatly enhanced should this approach prove successful. The application of full brain MRI imaging that informs neuropathology offers the potential to dramatically improve detection of neurotoxicity produced by new drugs and facilitate new drug development, review and approval processes, and to qualify an imaging biomarker of neuropathology.

Neuroprotective effect of the chemical chaperone, trehalose in a chronic MPTP-induced Parkinson's disease mouse model.

Parkinson's disease (PD) is a progressive motor disease of unknown etiology in the majority of cases. The clinical features of PD emerge due to selective degeneration of dopamine (DA) neurons in the substantia nigra pars compacta (SNc), which project to the caudate putamen (CPu) where they release DA. In the current in vivo mouse model study, we tested trehalose for its ability to protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced damage to DA neurons. Trehalose is a naturally occurring disaccharide present in plants and animals and appears capable of protecting cells against various environmental stresses. The effect of trehalose is likely due to its action as a pharmacological chaperone which promotes protein stability. In the present study, there were four treatment groups: saline only (control); probenecid only; MPTP+probenecid; and trehalose+MPTP+probenecid. MPTP-induced losses in tyrosine hydroxylase and DA transporter immunoreactivity in the ventral midbrain SNc and CPu were significantly reduced by trehalose. Decreases in CPu dopamine levels produced by MPTP were also blocked by trehalose. Microglial activation and astrocytic hypertrophy induced by MPTP were greatly reduced by trehalose, indicating protection against neuroinflammation. These effects are commensurate with the observed trehalose sparing of motor deficits produced by MPTP in this mouse model. Two tight junctional proteins, ZO-1 and occludin, are downregulated following MPTP treatment and trehalose blocks this effect. Likewise, the glucose transporter-1 that is expressed in brain endothelial cells is also protected by trehalose from MPTP-induced down-regulation. This study is the first to demonstrate using fluoro-turoquoise FT gel perfusion techniques, the protection afforded by trehalose from MPTP-induced damage to microvessels and endothelial and suggests that trehalose therapy may have the potential to slow or ameliorate PD pathology.

Neurovascular changes in acute, sub-acute and chronic mouse models of Parkinson's disease.

Although selective neurodegeneration of nigro-striatal dopaminergic neurons is widely accepted as a cause of Parkinson's disease (PD), the role of vascular components in the brain in PD pathology is not well understood. However, the neurodegeneration seen in PD is known to be associated with neuroinflammatory-like changes that can affect or be associated with brain vascular function. Thus, dysfunction of the capillary endothelial cell component of neurovascular units present in the brain may contribute to the damage to dopaminergic neurons that occurs in PD. An animal model of PD employing acute, sub-acute and chronic exposures of mice to methyl-phenyl-tetrahydropyridine (MPTP) was used to determine the extent to which brain vasculature may be damaged in PD. Fluoro-Turquoise gelatin labeling of microvessels and endothelial cells was used to determine the extent of vascular damage produced by MPTP. In addition, tyrosine hydroxylase (TH) and NeuN were employed to detect and quantify dopaminergic neuron damage in the striatum (CPu) and substantia nigra (SNc). Gliosis was evaluated through GFAP immunohistochemistry. MPTP treatment drastically reduced TH immunoreactive neurons in the SNc (20.68 ± 2.83 in acute; 22.98 ± 2.14 in sub-acute; 10.20 ± 2.24 in chronic vs 34.88 ± 2.91 in controls; p<0.001). Similarly, TH immunoreactive terminals were dramatically reduced in the CPu of MPTP treated mice. Additionally, all three MPTP exposures resulted in a decrease in the intensity, length, and number of vessels in both CPu and SNc. Degenerative vascular changes such as endothelial cell 'clusters' were also observed after MPTP suggesting that vasculature damage may be modifying the availability of nutrients and exposing blood cells and/or toxic substances to neurons and glia. In summary, vascular damage and degeneration could be an additional exacerbating factor in the progression of PD, and therapeutics that protect and insure vascular integrity may be novel treatments for PD.

Targeting DUSPs in glioblastomas - wielding a double-edged sword?

Several dual-specificity phosphatases (DUSPs) that play key roles in the direct or indirect inactivation of different MAP kinases (MAPKs) have been implicated in human cancers over the past decade. This has led to a growing interest in identifying DUSPs and their specific inhibitors for further testing and validation as therapeutic targets in human cancers. However, the lack of understanding of the complex regulatory mechanisms and cross-talks between MAPK signaling pathways, combined with the fact that DUSPs can act as a double-edged sword in cancer progression, calls for a more careful and thorough investigation. Among the various types of brain cancer, glioblastoma multiforme (GBM) is notorious for its aggressiveness and resistance to current treatment modalities. This has led to the search for new molecular targets, particularly those involving various signaling pathways. DUSPs appear to be a promising target, but much more information on DUSP targets and their effects on GBM is needed before potential therapies can be developed, tested, and validated. This review identifies and summarize the specific roles of DUSP1, DUSP4, DUSP6 and DUSP26 that have been implicated in GBM.

3,6'-dithiothalidomide improves experimental stroke outcome by suppressing neuroinflammation.

Tumor necrosis factor-α (TNF) plays a prominent role in the brain damage and functional deficits that result from ischemic stroke. It was recently reported that the thalidomide analog 3,6'-dithiothalidomide (3,6'-DT) can selectively inhibit the synthesis of TNF in cultured cells. We therefore tested the therapeutic potential of 3,6'-DT in a mouse model of focal ischemic stroke. Administration of 3,6'-DT immediately prior to a stroke or within 3 hr after the stroke reduced infarct volume, neuronal death, and neurological deficits, whereas thalidomide was effective only when administered prior to stroke. Neuroprotection was accompanied by decreased inflammation; 3,6'-DT-treated mice exhibited reduced expression of TNF, interleukin-1ß, and inducible nitric oxide synthase; reduced numbers of activated microglia/macrophages, astrocytes, and neutrophils; and reduced expression of intercellular adhesion molecule-1 in the ischemic brain tissue. 3,6'-DT treatment attenuated stroke-induced disruption of the blood-brain barrier by a mechanism that appears to involve suppression of matrix metalloproteinase-9 and preservation of occludin. Treatment with 3,6'-DT did not reduce ischemic brain damage in mice lacking TNF receptors, consistent with a critical role for suppression of TNF production and TNF signaling in the therapeutic action of 3,6'-DT. These findings suggest that anti-inflammatory mechanisms underlie the therapeutic actions of 3,6-DT in an animal model of stroke.

Effects of cerium oxide nanoparticles on the growth of keratinocytes, fibroblasts and vascular endothelial cells in cutaneous wound healing.

Rapid and effective wound healing requires a coordinated cellular response involving fibroblasts, keratinocytes and vascular endothelial cells (VECs). Impaired wound healing can result in multiple adverse health outcomes and, although antibiotics can forestall infection, treatments that accelerate wound healing are lacking. We now report that topical application of water soluble cerium oxide nanoparticles (Nanoceria) accelerates the healing of full-thickness dermal wounds in mice by a mechanism that involves enhancement of the proliferation and migration of fibroblasts, keratinocytes and VECs. The Nanoceria penetrated into the wound tissue and reduced oxidative damage to cellular membranes and proteins, suggesting a therapeutic potential for topical treatment of wounds with antioxidant nanoparticles.

Exendin-4 ameliorates motor neuron degeneration in cellular and animal models of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by a progressive loss of lower motor neurons in the spinal cord. The incretin hormone, glucagon-like peptide-1 (GLP-1), facilitates insulin signaling, and the long acting GLP-1 receptor agonist exendin-4 (Ex-4) is currently used as an anti-diabetic drug. GLP-1 receptors are widely expressed in the brain and spinal cord, and our prior studies have shown that Ex-4 is neuroprotective in several neurodegenerative disease rodent models, including stroke, Parkinson's disease and Alzheimer's disease. Here we hypothesized that Ex-4 may provide neuroprotective activity in ALS, and hence characterized Ex-4 actions in both cell culture (NSC-19 neuroblastoma cells) and in vivo (SOD1 G93A mutant mice) models of ALS. Ex-4 proved to be neurotrophic in NSC-19 cells, elevating choline acetyltransferase (ChAT) activity, as well as neuroprotective, protecting cells from hydrogen peroxide-induced oxidative stress and staurosporine-induced apoptosis. Additionally, in both wild-type SOD1 and mutant SOD1 (G37R) stably transfected NSC-19 cell lines, Ex-4 protected against trophic factor withdrawal-induced toxicity. To assess in vivo translation, SOD1 mutant mice were administered vehicle or Ex-4 at 6-weeks of age onwards to end-stage disease via subcutaneous osmotic pump to provide steady-state infusion. ALS mice treated with Ex-4 showed improved glucose tolerance and normalization of behavior, as assessed by running wheel, compared to control ALS mice. Furthermore, Ex-4 treatment attenuated neuronal cell death in the lumbar spinal cord; immunohistochemical analysis demonstrated the rescue of neuronal markers, such as ChAT, associated with motor neurons. Together, our results suggest that GLP-1 receptor agonists warrant further evaluation to assess whether their neuroprotective potential is of therapeutic relevance in ALS.

DNA immunization with HBsAg-based particles expressing a B cell epitope of amyloid ß-peptide attenuates disease progression and prolongs survival in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is an incurable and progressive neurodegenerative senile disorder associated with the brain accumulation of Aß plaques. Although vaccines that reduce Aß plaques can control AD, the rationale for their use at the onset of the disease remains debatable. Old humans and mice usually respond poorly to vaccines due to presumably age-related immunological impairments. Here, we report that by modifying vaccines, the poor responsiveness of old mice can be reversed. Unlike the Aß peptide vaccine, DNA immunizations with the amino-terminal Aß(1-11) fragment exposed on the surface of HBsAg particles elicit high levels of anti-Aß antibody both in young and old mice. Importantly, in AD model 3xTgAD mice, the vaccine reduced Aß plaques, ameliorated cognitive impairments and, surprisingly, significantly increased life span. Hence, we propose that vaccines targeting Aß(1-11) can efficiently combat AD-induced pathological alterations and provide survival benefit in patients with AD.

Effect of acetazolamide on aquaporin-1 and fluid flow in cultured choroid plexus.

Acetazolamide (AZA), used in treatment of early or infantile hydrocephalus, is effective in some cases, while its effect on the choroid plexus (CP) remains ill-defined. The drug reversibly inhibits aquaporin-4 (AQP4), the most ubiquitous "water pore" in the brain, and perhaps modulation of AQP1 (located apically on CP cells) by AZA may reduce cerebrospinal fluid (CSF) production. We sought to elucidate the effect of AZA on AQP1 and fluid flow in CP cell cultures.CP tissue culture from 10-day Sprague-Dawley rats and a TRCSF-B cell line were grown on Transwell permeable supports and treated with 100 µM AZA. Fluid assays to assess direction and extent of fluid flow, and AQP1 expression patterns by immunoblot, Immuncytochemistry (ICC), and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were performed.Immunoblots and ICC analyses showed a decrease in AQP1 protein shortly after AZA treatment (lowest at 12 h), with transient AQP1 reduction mediated by mRNA expression (lowest at 6 h). Transwell fluid assays indicated a fluid shift at 2 h, before significant changes in AQP1 mRNA or protein levels.Timing of AZA effect on AQP1 suggests the drug alters protein transcription, while affecting fluid flow by a concomitant method. It is plausible that other mechanisms account for these phenomena, as the processes may occur independently.

Chronic nicotine administration impairs activation of cyclic AMP-response element binding protein and survival of newborn cells in the dentate gyrus.

Chronic intake of nicotine can impair hippocampal plasticity, but the underlying mechanism is poorly understood. Here, we demonstrate that chronic nicotine administration in adult rats inactivates the cyclic AMP-response element binding protein (CREB), a transcription factor that regulates neurogenesis and other plasticity-related processes necessary for learning and memory. Consequently, we showed that impaired CREB signaling is associated with a significant decline in the production of new neurons in the dentate gyrus. Combining retrovirus labeling with gene expression approaches, we found that chronic nicotine administration reduces the number of adult-generated granule neurons by decreasing the survival of newborn cells but not the proliferation of progenitor cells. Additionally, we found that retroviral-mediated expression of a constitutively active CREB in the dentate gyrus rescues survival of newborn cells and reverses the nicotine-induced decline in the number of mature granule neurons. Prolonged nicotine exposure also compromises CREB activation and reduces the viability of progenitor cells in vitro, thereby suggesting that nicotine may exert its adverse effects directly on immature cells in vivo. Taken together, these data demonstrate that inhibition of CREB activation is responsible for the nicotine-induced impairment of hippocampal plasticity.

Notch activation enhances the microglia-mediated inflammatory response associated with focal cerebral ischemia.

BACKGROUND AND PURPOSE: Activation of Notch worsens ischemic brain damage as antisense knockdown or pharmacological inhibition of the Notch pathway reduces the infarct size and improves the functional outcome in a mouse model of stroke. We sought to determine whether Notch activation contributes to postischemic inflammation by directly modulating the microglial innate response. METHODS: The microglial response and the attendant inflammatory reaction were evaluated in Notch1 antisense transgenic (Tg) and in nontransgenic (non-Tg) mice subjected to middle cerebral artery occlusion with or without treatment with a γ-secretase inhibitor (GSI). To investigate the impact of Notch on microglial effector functions, primary mouse microglia and murine BV-2 microglial cell line were exposed to oxygen glucose deprivation or lipopolysaccharide in the presence or absence of GSI. Immunofluorescence labeling, Western blotting, and reverse-transcription polymerase chain reaction were performed to measure microglial activation and production of inflammatory cytokines. The nuclear translocation of nuclear factor-κB in microglia was assessed by immunohistochemistry. The neurotoxic potential of microglia was determined in cocultures. RESULTS: Notch1 antisense mice exhibit significantly lower numbers of activated microglia and reduced proinflammatory cytokine expression in the ipsilateral ischemic cortices compared to non-Tg mice. Microglial activation also was attenuated in Notch1 antisense cultures and in non-Tg cultures treated with GSI. GSI significantly reduced nuclear factor-κB activation and expression of proinflammatory mediators and markedly attenuated the neurotoxic activity of microglia in cocultures. CONCLUSIONS: These findings establish a role for Notch signaling in modulating the microglia innate response and suggest that inhibition of Notch might represent a complementary therapeutic approach to prevent reactive gliosis in stroke and neuroinflammation-related degenerative disorders.

Evidence for altered Numb isoform levels in Alzheimer's disease patients and a triple transgenic mouse model.

The cell fate determinant Numb exists in four alternatively spliced variants that differ in the length of their PTB (phosphotyrosine-binding domain, either lacking or containing an 11 amino acid insertion) and PRR (proline-rich region, either lacking or containing a 48 amino acid insertion). We previously reported that Numb switches from isoforms containing the PTB insertion to isoforms lacking this insertion in neural cultures subjected to stress induced by trophic factor withdrawal. The switch in Numb isoforms enhances the generation of amyloid-ß peptide (Aß), the principle component of senile plaques in Alzheimer's disease (AD). Here we examine the expression of the Numb isoforms in brains from AD patients and triple transgenic (3xTg) AD mice. We found that levels of the Numb isoforms lacking the PTB insertion are significantly elevated in the parietal cortex but not in the cerebellum of AD patients when compared to control subjects. Levels of Numb isoforms lacking the PTB insertion were also elevated in the cortex but not cerebellum of 12 month-old 3xTg AD mice with Aß deposits compared to younger 3xTg-AD mice and to non-transgenic mice. Exposure of cultured neurons to Aß resulted in an increase in the levels of Numb isoforms lacking the PTB domain, consistent with a role for Aß in the aberrant expression of Numb in vulnerable brain regions of AD patients and mice. Collectively, the data show that altered expression of Numb isoforms in vulnerable neurons occurs during AD pathogenesis and suggest a role for Numb in the disease process.

Expression of aquaporin 1 and 4 in a congenital hydrocephalus rat model.

BACKGROUND: Hydrocephalus occurs because of an imbalance of bulk fluid flow in the brain, and aquaporins (AQPs) play pivotal roles in cerebral water movement as essential mediators during edema and fluid accumulation. AQP1 is a water channel found in the choroid plexus (CP), and AQP4 is expressed at the brain-CSF interfaces and astrocytic end feet; excessive fluid accumulation may involve expression of changes in these AQPs during various stages of hydrocephalus. OBJECTIVE: To determine the alterations of CP AQP1 expression in congenital hydrocephalus; detect hydrocephalus-induced AQP1 expression in the cortical parenchyma, ependyma, and pia mater of hydrocephalic animals; and evaluate AQP4 expression in congenital hydrocephalus through progressive stages of the condition. METHODS: We evaluated differential expression of AQPs 1 and 4 in the congenital hydrocephalus Texas rat at postnatal days 5, 10, and 26 in isolated CP and cortex by enzyme-linked immunosorbent assay, Western blot, quantitative reverse transcriptase polymerase chain reaction, and immunohistochemistry. RESULTS: The CP exhibited a 34% decrease in AQP1 expression in young hydrocephalic pups (postnatal days 5 and 10), which became normal (postnatal day 26) just before death. With advancing hydrocephalus, expression of AQPs 1 and 4 increased at the brain-CSF interfaces; AQP1 was localized to the endothelium of cortical capillaries with increased AQP4 expression in surrounding astrocytes end feet. AQP1 expression level was increased in the pia mater, with prominent AQP4 expression in the subpial layers. Subependymal capillaries expressed AQP1 in the endothelium, with increasing AQP4 expression in surrounding astrocytes. Hydrocephalic animals (postnatal day 26) had significant nonendothelial (CD34) AQP1 expression in the septal nucleus of the basal forebrain, an area affected by increased intracranial pressure. CONCLUSION: Biphasic AQP1 expression in the CP with increased AQPs 1 and 4 at the brain-fluid interfaces may indicate compensatory mechanisms to regulate choroidal cerebrospinal fluid secretion and increase parenchymal fluid absorption in the high-pressure hydrocephalic condition.