RESUMO
Alzheimer's disease (AD) and osteoporosis often coexist in the elderly. Although observational studies suggest an association between these two diseases, the pathophysiologic link between AD and skeletal health has been poorly defined. We examined the skeletal phenotype of 5xFAD mice, an AD model with accelerated neuron-specific amyloid-ß accumulation causing full-blown AD phenotype by the age of 8 months. Micro-computed tomography indicated significantly lower trabecular and cortical bone parameters in 8-month-old male, but not female, 5xFAD mice than sex-matched wild-type littermates. Dynamic histomorphometry revealed reduced bone formation and increased bone resorption, and quantitative RT-PCR showed elevated skeletal RANKL gene expression in 5xFAD males. These mice also had diminished body fat percentage with unaltered lean mass, as determined by dual-energy X-ray absorptiometry (DXA), and elevated Ucp1 mRNA levels in brown adipose tissue, consistent with increased sympathetic tone, which may contribute to the osteopenia observed in 5xFAD males. Nevertheless, no significant changes could be detected between male 5xFAD and wild-type littermates regarding the serum and skeletal concentrations of norepinephrine. Thus, brain-specific amyloid-ß pathology is associated with osteopenia and appears to affect both bone formation and bone resorption. Our findings shed new light on the pathophysiologic link between Alzheimer's disease and osteoporosis.
RESUMO
Fibroblast growth factor 23 (FGF23) production has recently been shown to increase downstream of Gαq/11-PKC signaling in osteocytes. Inactivating mutations in the gene encoding Gα11 (GNA11) cause familial hypocalciuric hypercalcemia (FHH) due to impaired calcium-sensing receptor signaling. We explored the effect of Gα11 deficiency on FGF23 production in mice with heterozygous (Gna11+/-) or homozygous (Gna11-/-) ablation of Gna11. Both Gna11+/- and Gna11-/- mice demonstrated hypercalcemia and mildly raised parathyroid hormone levels, consistent with FHH. Strikingly, these mice also displayed increased serum levels of total and intact FGF23 and hypophosphatemia. Gna11-/- mice showed augmented Fgf23 mRNA levels in the liver and heart, but not in bone or bone marrow, and also showed evidence of systemic inflammation with elevated serum IL-1ß levels. Furin gene expression was significantly increased in the Gna11-/- liver, suggesting enhanced FGF23 cleavage despite the observed rise in circulating intact FGF23 levels. Gna11-/- mice had normal renal function and reduced serum levels of glycerol-3-phosphate, excluding kidney injury as the primary cause of elevated intact FGF23 levels. Thus, Gα11 ablation caused systemic inflammation and excess serum FGF23 in mice, suggesting that patients with FHH - at least those with GNA11 mutations - may be at risk for these complications.
Assuntos
Modelos Animais de Doenças , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP , Hipercalcemia , Camundongos Knockout , Animais , Feminino , Masculino , Camundongos , Fatores de Crescimento de Fibroblastos/sangue , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Hipercalcemia/genética , Hipercalcemia/congênito , Hipercalcemia/sangue , Hipercalcemia/metabolismo , Hipofosfatemia/genética , Hipofosfatemia/metabolismo , Interleucina-1beta/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/sangue , Fígado/metabolismo , Hormônio Paratireóideo/sangue , Hormônio Paratireóideo/metabolismo , Transdução de SinaisRESUMO
OBJECTIVES: Microglial activation is critical for modulating the neuroinflammatory process and the pathological progression of neurodegenerative diseases, such as Alzheimer's disease (AD). Microglia are involved in forming barriers around extracellular neuritic plaques and the phagocytosis of ß-amyloid peptide (Aß). In this study, we tested the hypothesis that periodontal disease (PD) as a source of infection alters inflammatory activation and Aß phagocytosis by the microglial cells. METHODS: Experimental PD was induced using ligatures in C57BL/6 mice for 1, 10, 20, and 30 days to assess the progression of PD. Animals without ligatures were used as controls. Maxillary bone loss and local periodontal tissue inflammation associated with the development of PD were confirmed by morphometric bone analysis and cytokine expression, respectively. The frequency and the total number of activated microglia (CD45+ CD11b+ MHCII+) in the brain were analyzed by flow cytometry. Mouse microglial cells (1 × 105) were incubated with heat-inactivated bacterial biofilm isolated from the ligatures retrieved from the teeth or with Klebsiella variicola, a relevant PD-associated bacteria in mice. Expression of pro-inflammatory cytokines, toll-like receptors (TLR), and receptors for phagocytosis was measured by quantitative PCR. The phagocytic capacity of microglia to uptake ß-amyloid was analyzed by flow cytometry. RESULTS: Ligature placement caused progressive periodontal disease and bone resorption that was already significant on day 1 post-ligation (p < 0.05) and continued to increase until day 30 (p < 0.0001). The severity of periodontal disease increased the frequency of activated microglia in the brains on day 30 by 36%. In parallel, heat-inactivated PD-associated total bacteria and Klebsiella variicola increased the expression of TNFα, IL-1ß, IL-6, TLR2, and TLR9 in microglial cells (1.6-, 83-, 3.2-, 1.5-, 1.5-fold, respectively p < 0.01). Incubation of microglia with Klebsiella variicola increased the Aß-phagocytosis by 394% and the expression of the phagocytic receptor MSR1 by 33-fold compared to the non-activated cells (p < 0.0001). CONCLUSIONS: We showed that inducing PD in mice results in microglia activation in vivo and that PD-associated bacteria directly promote a pro-inflammatory and phagocytic phenotype in microglia. These results support a direct role of PD-associated pathogens in neuroinflammation.
Assuntos
Microglia , Doenças Periodontais , Animais , Camundongos , Camundongos Endogâmicos C57BL , Klebsiella , Peptídeos beta-AmiloidesRESUMO
Gulf War Illness (GWI) is an unrelenting multi-symptom illness with chronic central nervous system and peripheral pathology affecting veterans from the 1991 Gulf War and for which effective treatment is lacking. An increasing number of studies indicate that persistent neuroinflammation is likely the underlying cause of cognitive and mood dysfunction that affects veterans with GWI. We have previously reported that fingolimod, a drug approved for the treatment of relapsing-remitting multiple sclerosis, decreases neuroinflammation and improves cognition in a mouse model of Alzheimer's disease. In this study, we investigated the effect of fingolimod treatment on cognition and neuroinflammation in a mouse model of GWI. We exposed C57BL/6 J male mice to GWI-related chemicals pyridostigmine bromide, DEET, and permethrin, and to mild restraint stress for 28 days (GWI mice). Control mice were exposed to the chemicals' vehicle only. Starting 3 months post-exposure, half of the GWI mice and control mice were orally treated with fingolimod (1 mg/kg/day) for 1 month, and the other half were left untreated. Decreased memory on the Morris water maze test was detected in GWI mice compared to control mice and was reversed by fingolimod treatment. Immunohistochemical analysis of brain sections with antibodies to Iba1 and GFAP revealed that GWI mice had increased microglia activation in the hippocampal dentate gyrus, but no difference in reactive astrocytes was detected. The increased activation of microglia in GWI mice was decreased to the level in control mice by treatment with fingolimod. No effect of fingolimod treatment on gliosis in control mice was detected. To explore the signaling pathways by which decreased memory and increased neuroinflammation in GWI may be protected by fingolimod, we investigated the involvement of the inflammatory signaling pathways of protein kinase R (PKR) in the cerebral cortex of these mice. We found increased phosphorylation of PKR in the brain of GWI mice compared to controls, as well as increased phosphorylation of its most recognized downstream effectors: the α subunit of eukaryotic initiation factor 2 (eIF2α), IκB kinase (IKK), and the p65 subunit of nuclear factor-κB (NFκB-p65). Furthermore, we found that the increased phosphorylation level of these three proteins were suppressed in GWI mice treated with fingolimod. These results suggest that activation of PKR and NFκB signaling may be important for the regulation of cognition and neuroinflammation in the GWI condition and that fingolimod, a drug already approved for human use, may be a potential candidate for the treatment of GWI.
Assuntos
Cloridrato de Fingolimode , Síndrome do Golfo Pérsico , Animais , Masculino , Camundongos , Amnésia/metabolismo , Modelos Animais de Doenças , Cloridrato de Fingolimode/uso terapêutico , Cloridrato de Fingolimode/metabolismo , Cloridrato de Fingolimode/farmacologia , Guerra do Golfo , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/metabolismo , Camundongos Endogâmicos C57BL , Microglia , Doenças Neuroinflamatórias , NF-kappa B/metabolismo , Síndrome do Golfo Pérsico/induzido quimicamente , Síndrome do Golfo Pérsico/tratamento farmacológico , Síndrome do Golfo Pérsico/metabolismo , Proteínas Quinases/metabolismo , Proteínas Quinases/farmacologia , Proteínas Quinases/uso terapêutico , Brometo de Piridostigmina/uso terapêutico , Brometo de Piridostigmina/farmacologiaRESUMO
Sphingolipid-1-phosphate (S1P) signaling through the activation S1P receptors (S1PRs) plays critical roles in cellular events in the brain. Aberrant S1P metabolism has been identified in the brains of Alzheimer's disease (AD) patients. Our recent studies have shown that treatment with fingolimod, an analog of sphingosine, provides neuroprotective effects in five familiar Alzheimer disease (5xFAD) transgenic mice, resulting in the reduction of amyloid-ß (Aß) neurotoxicity, inhibition of activation of microglia and astrocytes, increased hippocampal neurogenesis, and improved learning and memory. However, the pathways by which dysfunctional S1P and S1PR signaling may associate with the development of AD-like pathology remain unknown. In this study, we investigated the alteration of signaling of S1P/S1P receptor 1 (S1PR1), the most abundant S1PR subtype in the brain, in the cortex of 5xFAD transgenic mice at 3, 8, and 14 months of age. Compared to non-transgenic wildtype (WT) littermates, we found significant decreased levels of sphingosine kinases (SphKs), increased S1P lyase (S1PL), and increased S1PR1 in 8- and 14-month-old, but not in 3-month-old 5xFAD mice. Furthermore, we detected increased activation of the S1PR1 downstream pathway of Akt/mTor/Tau signaling in aging 5xFAD mice. Treatment with fingolimod from 1 to 8 months of age reversed the levels of SphKs, S1PL, and furthermore, those of S1PR1 and its downstream pathway of Akt/mTor/Tau signaling. Together the data reveal that dysregulation of S1P and S1PR signaling may associate with the development of AD-like pathology through Akt/mTor/Tau signaling.
Assuntos
Doença de Alzheimer , Esfingosina , Camundongos , Animais , Cloridrato de Fingolimode/farmacologia , Doença de Alzheimer/metabolismo , Receptores de Esfingosina-1-Fosfato , Proteínas Proto-Oncogênicas c-akt , Lisofosfolipídeos/metabolismo , Modelos Animais de Doenças , Camundongos Transgênicos , Serina-Treonina Quinases TORRESUMO
Alzheimer's Disease (AD) is the most common form of dementia in older adults and has a devastating impact on the patient's quality of life, which creates a significant socio-economic burden for the affected individuals and their families. In recent years, studies have identified a relationship between periodontitis and AD. Periodontitis is an infectious/inflammatory disease that destroys the supporting periodontal structure leading to tooth loss. Dysbiosis of the oral microbiome plays a significant role in the onset and development of periodontitis exhibiting a shift to overgrowth of pathobionts in the normal microflora with increasing local inflammation. Fusobacterium nucleatum is a common pathogen that significantly overgrows in periodontitis and has also been linked to various systemic diseases. Earlier studies have reported that antibodies to F. nucleatum can be detected in the serum of patients with AD or cognitive impairment, but a causal relationship and a plausible mechanism linking the two diseases have not been identified. In this study, we conducted both in vivo and in vitro experiments and found that F. nucleatum activates microglial cells causing morphological changes, accelerated proliferation and enhanced expression of TNF-α and IL-1ß in microglial cells. In our in vivo experiments, we found that F. nucleatum-induced periodontitis resulted in the exacerbation of Alzheimer's symptoms in 5XFAD mice including increased cognitive impairment, beta-amyloid accumulation and Tau protein phosphorylation in the mouse cerebrum. This study may suggest a possible link between a periodontal pathogen and AD and F. nucleatum could be a risk factor in the pathogenesis of AD. We are currently further identifying the pathways through which F. nucleatum modulates molecular elements in enhancing AD symptoms and signs. Data are available via ProteomeXchange with identifier PXD033147.
RESUMO
Periodontal disease (PD) has been suggested to be a risk factor for Alzheimer's disease (AD). We tested the impact of ligature-induced PD on 5xFAD mice and WT littermates. At baseline, 5xFAD mice presented significant alveolar bone loss compared to WT mice. After the induction of PD, both WT and 5xFAD mice experienced alveolar bone loss. PD increased the level of Iba1-immunostained microglia in WT mice. In 5xFAD mice, PD increased the level of insoluble Aß42. The increased level in Iba1 immunostaining that parallels the accumulation of Aß in 5xFAD mice was not affected by PD except for a decrease in the dentate gyrus. Analysis of double-label fluorescent images showed a decline in Iba1 in the proximity of Aß plaques in 5xFAD mice with PD compared to those without PD suggesting a PD-induced decrease in plaque-associated microglia (PAM). PD reduced IL-6, MCP-1, GM-CSF, and IFN-γ in brains of WT mice and reduced IL-10 in 5xFAD mice. The data demonstrated that PD increases neuroinflammation in WT mice and disrupts the neuroinflammatory response in 5xFAD mice and suggest that microglia is central to the association between PD and AD.
Assuntos
Doença de Alzheimer/patologia , Microglia/patologia , Periodontite/patologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Quimiocina CCL2/metabolismo , Modelos Animais de Doenças , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Inflamação/metabolismo , Inflamação/patologia , Interferon gama/metabolismo , Interleucina-6/metabolismo , Masculino , Camundongos , Microglia/metabolismo , Periodontite/metabolismo , Placa Amiloide/metabolismo , Placa Amiloide/patologiaRESUMO
A large body of evidence indicates that dysregulation of cerebral biometals (Fe, Cu, Zn) and their interactions with amyloid precursor protein (APP) and Aß amyloid may contribute to the Alzheimer's disease (AD) Aß amyloid pathology. However, the molecular underpinnings associated with the interactions are still not fully understood. Herein we have further validated the exacerbation of Aß oligomerization by Cu and H2O2 in vitro. We have also reported that Cu enhanced APP translations via its 5' untranslated region (5'UTR) of mRNA in SH-SY5Y cells, and increased Aß amyloidosis and expression of associated pro-inflammatory cytokines such as MCP-5 in Alzheimer's APP/PS1 doubly transgenic mice. This preliminary study may further unravel the pathogenic role of Cu in Alzheimer's Aß amyloid pathogenesis, warranting further investigation.
Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Precursor de Proteína beta-Amiloide , Cobre/toxicidade , Biossíntese de Proteínas , Multimerização Proteica/efeitos dos fármacos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/biossíntese , Precursor de Proteína beta-Amiloide/química , Precursor de Proteína beta-Amiloide/genética , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos TransgênicosRESUMO
Lipid metabolism is abnormal in Alzheimer's disease (AD) brain leading to ceramide and sphingosine accumulation and reduced levels of brain sphingosine-1-phosphate (S1P). We hypothesize that changes in S1P signaling are central to the inflammatory and immune-pathogenesis of AD and the therapeutic benefits of fingolimod, a structural analog of sphingosine that is FDA approved for the treatment of multiple sclerosis. We recently reported that the neuroprotective effects of fingolimod in 5xFAD transgenic AD mice treated from 1-3 months of age were greater at 1 mg/kg/day than at 5 mg/kg/day. Here we performed a dose-response study using fingolimod from 0.03 to 1 mg/kg/day in 5xFAD mice treated from 1-8 months of age. At 1 mg/kg/day, fingolimod decreased both peripheral blood lymphocyte counts and brain Aß levels, but at the lowest dose tested (0.03 mg/kg/day), we detected improved memory, decreased activation of brain microglia and astrocytes, and restored hippocampal levels of GABA and glycerophosphocholine with no effect on circulating lymphocyte counts. These findings suggests that, unlike the case in multiple sclerosis, fingolimod may potentially have therapeutic benefits in AD at low doses that do not affect peripheral lymphocyte function.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Encéfalo/efeitos dos fármacos , Reposicionamento de Medicamentos , Cloridrato de Fingolimode/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Cloridrato de Fingolimode/uso terapêutico , Camundongos , Camundongos Transgênicos , Microglia/efeitos dos fármacos , Microglia/patologia , Ácido gama-Aminobutírico/metabolismoRESUMO
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by extracellular deposits of fibrillary ß-amyloid (Aß) plaques in the brain that initiate an inflammatory process resulting in neurodegeneration. The neuronal loss associated with AD results in gross atrophy of affected regions causing a progressive loss of cognitive ability and memory function, ultimately leading to dementia. Growing evidence suggests that vasoactive intestinal peptide (VIP) could be beneficial for various neurodegenerative diseases, including AD. The study investigated the effects of VIP on 5xFAD, a transgenic mouse model of AD. Toward this aim, we used 20 5xFAD mice in two groups (n = 10 each), VIP-treated (25 ng/kg i.p. injection, three times per week) and saline-treated (the drug's vehicle) following the same administration regimen. Treatment started at 1 month of age and ended 2 months later. After 2 months of treatment, the mice were euthanized, their brains dissected out, and immunohistochemically stained for Aß40 and Aß42 on serial sections. Then, plaque analysis and stereological morphometric analysis were performed in different brain regions. Chronic VIP administration in 5xFAD mice significantly decreased the levels of Aß40 and Aß42 plaques in the subiculum compared to the saline treated 5xFAD mice. VIP treatment also significantly decreased Aß40 and Aß42 plaques in cortical areas and significantly increased the hippocampus/cerebrum and corpus callosum/cerebrum ratio but not the cerebral cortex/cerebrum ratio. In summary, we found that chronic administration of VIP significantly decreased Aß plaques and preserved against atrophy for related brain regions in 5xFAD AD mice.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Peptídeo Intestinal Vasoativo/uso terapêutico , Peptídeos beta-Amiloides/metabolismo , Animais , Atrofia/tratamento farmacológico , Encéfalo/patologia , Feminino , Camundongos , Fármacos Neuroprotetores/administração & dosagem , Fármacos Neuroprotetores/farmacologia , Peptídeo Intestinal Vasoativo/administração & dosagem , Peptídeo Intestinal Vasoativo/farmacologiaRESUMO
Interest in brain-derived neurotrophic factor (BDNF) was greatly enhanced when it was recognized that its expression is reduced in neurodegenerative disorders, especially in Alzheimer's disease (AD). BDNF signaling through the TrkB receptor has a central role in promoting synaptic transmission, synaptogenesis, and facilitating synaptic plasticity making the BDNF-TrkB signaling pathway an attractive candidate for targeted therapies. Here we investigated the early effect of the small molecule TrkB agonist, 7,8 dihydroxyflavone (7,8-DHF), on AD-related pathology, dendritic arborization, synaptic density, and neurochemical changes in the 5xFAD mouse model of AD. We treated 5xFAD mice with 7,8-DHF for 2 months beginning at 1 month of age. We found that, in this model of AD, 7,8-DHF treatment decreased cortical Aß plaque deposition and protected cortical neurons against reduced dendritic arbor complexity but had no significant impact on the density of dendritic spines. In addition 7,8-DHF treatment protected against hippocampal increase in the level of choline-containing compounds and glutamate loss, but had no significant impact on hippocampal neurogenesis.
Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Flavonas/farmacologia , Fármacos Neuroprotetores/farmacologia , Peptídeos beta-Amiloides/metabolismo , Animais , Espinhas Dendríticas/efeitos dos fármacos , Espinhas Dendríticas/patologia , Modelos Animais de Doenças , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Camundongos , Fragmentos de Peptídeos/metabolismoRESUMO
Dysfunction in the resolution of inflammation may play a key role in Alzheimer's disease (AD). In this study, we found that the levels of specialized pro-resolving lipid mediators (SPMs) in the hippocampus of 5xFAD mice are significantly lower than in non-transgenic littermates. We, therefore, tested the hypothesis that treatment with resolvin E1 (RvE1) and lipoxin A4 (LXA4) alone or in combination will reverse the neuroinflammatory process and decrease Aß pathology. 5xFAD mice were treated intraperitoneally starting at 1month of age with RvE1 or LXA4 alone or in combination at a dose of 1.5 µg/kg, 3 times a week until 3months of age. We found that treatment with RvE1 or LXA4 alone or in combination increased the concentration of RvE1, LXA4, and RvD2 in the hippocampus as measured by ELISA. Combination treatment of RvE1 and LXA4 had a more potent effect on the activation of microglia and astrocytes than either treatment alone, measured by immunohistochemistry with Iba1 and GFAP antibodies, respectively. The concentrations of Aß40 and Aß42 were measured by ELISA and the percentage of Aß plaques were analyzed by immunohistochemistry. All treatments single and in combination, decreased the measures of Aß pathology and restored the homeostasis reversing the inflammatory process for inflammatory cytokines and chemokines (GM-CSF, IFN-γ, IL-1ß, IL-6, IL-10, TNF-α, MCP-1, MIP-1α, MIP-1ß, and RANTES) as measured by multiplex immunoassay. Overall, the study showed that the levels of SPMs in the hippocampus of 5xFAD mice were significantly lower than in wild-type mice; that treatment with RvE1 and LXA4 restored the level of these compounds, reversed the inflammatory process, and decreased the neuroinflammation associated with Aß pathology in 5xFAD mice.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Anti-Inflamatórios não Esteroides/administração & dosagem , Modelos Animais de Doenças , Ácido Eicosapentaenoico/análogos & derivados , Lipoxinas/administração & dosagem , Doença de Alzheimer/patologia , Animais , Quimioterapia Combinada , Ácido Eicosapentaenoico/administração & dosagem , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Camundongos , Camundongos TransgênicosRESUMO
Gulf War Illness (GWI) is a chronic disease that affects the 1991 Gulf War (GW) veterans for which treatment is lacking. It has been hypothesized that drugs used to protect military personnel from chemical attacks and insects during the war: pyridostigmine bromide (PB),N, N-diethyl-m-toluamide (DEET), and permethrin (PER) together with stress may have contributed collectively and synergistically to generate GWI. There is a need to find markers of pathology to be used in pre-clinical trials. For this purpose we employed a previously validated mouse model of GWI evoked by daily exposure to PB (1.3â¯mg/kg), DEET (40â¯mg/kg), PER (0.13â¯mg/kg), and 5â¯min of restraint stress for 28â¯days to analyze behavior, brain pathology and neurochemical outcomes three months later. GWI-model mice were characterized by increased anxiety, decreased hippocampal levels of N-acetyl aspartate, GABA, the GABA-producing enzyme GAD-67 and microglial activation. We also observed that GWI model was sexually dimorphic on some measures: males had increased while females had decreased protein levels of the acetylcholine-synthesizing enzyme, choline acetyltransferase, in the septum and hippocampus and decreased levels of the receptor for brain-derived neurotrophic factor, TrkB140, in the hippocampus. Increased hippocampal levels of nerve growth factor were detected in males only. Together the data show behavioral and neuropathological abnormalities detected at 3â¯months post-exposure and that some of them are sexually dimorphic. Future preclinical studies for GWI may take advantage of this short latency model and should include both males and females as their response to treatment may differ.
Assuntos
Acetilcolina/metabolismo , Ansiedade/complicações , Modelos Animais de Doenças , Encefalite/complicações , Síndrome do Golfo Pérsico/etiologia , Ácido gama-Aminobutírico/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , DEET/administração & dosagem , Feminino , Masculino , Camundongos Transgênicos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Permetrina/administração & dosagem , Síndrome do Golfo Pérsico/metabolismo , Brometo de Piridostigmina/administração & dosagem , Estresse Psicológico/complicaçõesRESUMO
Sphingosine 1-phosphate (SP1) receptors may be attractive targets for modulation of inflammatory processes in neurodegenerative diseases. Recently fingolimod, a functional S1P1 receptor antagonist, was introduced for treatment of multiple sclerosis. We postulated that anti-inflammatory mechanisms of fingolimod might also be protective in Alzheimer's disease (AD). Therefore, we treated a mouse model of AD, the 5xFAD model, with two doses of fingolimod (1 and 5 mg/kg/day) and measured the response of numerous markers of Aß pathology as well as inflammatory markers and neurochemistry using biochemical, immunohistochemistry and high resolution magic angle spinning magnetic resonance spectroscopy (MRS). In mice at 3 months of age, we found that fingolimod decreased plaque density as well as soluble plus insoluble Aß measured by ELISA. Fingolimod also decreased GFAP staining and the number of activated microglia. Taurine has been demonstrated to play a role as an endogenous anti-inflammatory molecule. Taurine levels, measured using MRS, showed a very strong inverse correlation with GFAP levels and ELISA measurements of Aß, but not with plaque density or activated microglia levels. MRS also showed an effect of fingolimod on glutamate levels. Fingolimod at 1 mg/kg/day provided better neuroprotection than 5 mg/kg/day. Together, these data suggest a potential therapeutic role for fingolimod in AD.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Anti-Inflamatórios/administração & dosagem , Cloridrato de Fingolimode/administração & dosagem , Peptídeos beta-Amiloides/análise , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Camundongos , Resultado do TratamentoRESUMO
G-protein coupled dopamine and metabotropic glutamate receptors (mGlu) can modulate neurotransmission during Parkinson's disease (PD)-like neurodegeneration. PET imaging studies in a unilateral dopamine denervation model (6-OHDA) showed a significant inverse correlation of presynaptic mGlu4 and postsynaptic mGlu5 expression in the striatum and rapidly declining mGlu4 and enhanced mGlu5 expression in the hippocampus during progressive degeneration over time. Immunohistochemical studies verified the decreased mGlu4 expression in the hippocampus on the lesion side but did not show difference in mGlu5 expression between lesion and control side. Pharmacological MRI studies showed enhanced hemodynamic response in several brain areas on the lesion side compared to the control side after challenge with mGlu4 positive allosteric modulator or mGlu5 negative allosteric modulator. However, mGlu4 response was biphasic having short enhancement followed by negative response on both sides of brain. Studies in mGlu4 expressing cells demonstrated that glutamate induces cooperative increase in binding of mGlu4 ligands - especially at high glutamate levels consistent with in vivo concentration. This suggests that mGlu allosteric modulators as drug candidates will be highly sensitive to changes in glutamate concentration and hence metabolic state. These experiments demonstrate the importance of the longitudinal imaging studies to investigate temporal changes in receptor functions to obtain individual response for experimental drugs.
Assuntos
Doenças Neurodegenerativas/diagnóstico por imagem , Doenças Neurodegenerativas/metabolismo , Transtornos Parkinsonianos/diagnóstico por imagem , Transtornos Parkinsonianos/metabolismo , Receptores Acoplados a Proteínas G/fisiologia , Animais , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Ácido Glutâmico/farmacologia , Masculino , Ligação Proteica/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/agonistas , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/metabolismoRESUMO
We investigated a triple transgene Alzheimer's disease (AD) mouse model that recapitulates many of the neurochemical, anatomic, pathologic and behavioral defects seen in human AD. We studied the mice as a function of age and brain region and investigated potential therapy with the non-steroidal anti-inflammatory drug ibuprofen. Magnetic resonance spectroscopy (MRS) showed alterations characteristic of AD (i.e. increased myo-inositol and decreased N-acetylaspartate (NAA)). Mice at 6 months of age showed an increase in myo-inositol in the hippocampus at a time when the Aß is intracellular, but not in amygdala or cortex. Myo-inositol increased as a function of age in the amygdala, cortex and striatum while NAA decreased only in the hippocampus and cortex at 17-23 months of age. Ibuprofen protected the increase of myo-inositol at six months of age in the hippocampus, but had no effect at 17-23 months of age (a time when Aß is extracellular). In vivo MRI and MRS showed that at 17-23 months of age there was a significant protective effect of ibuprofen on hippocampal volume and NAA loss. Together, these data show the following: the increase in myo-inositol occurs before the decrease in NAA in hippocampus but not cortex; the hippocampus shows earlier changes than does the amygdale or cortex consistent with earlier deposition of Aß40-42 in the hippocampus and ibuprofen protects against multiple components of the AD pathology. These data also show a profound effect of housing on this particular mouse model.
Assuntos
Envelhecimento/patologia , Doença de Alzheimer/genética , Anti-Inflamatórios não Esteroides/farmacologia , Química Encefálica/efeitos dos fármacos , Química Encefálica/genética , Abrigo para Animais , Ibuprofeno/farmacologia , Transgenes/genética , Tonsila do Cerebelo/efeitos dos fármacos , Tonsila do Cerebelo/patologia , Animais , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos TransgênicosRESUMO
Amyotrophic lateral sclerosis (ALS) is an enigmatic neurodegenerative disorder without any effective treatment characterized by loss of motor neurons (MNs) that results in rapidly progressive motor weakness and early death due to respiratory failure. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family known to play a prominent role in the differentiation and survival of MNs. The flavonoid 7,8-dihydroxyflavone (7,8-DHF) is a potent and selective small molecule tyrosine kinase receptor B (TrkB) agonist that mimics the effects of BDNF. In the present study, we evaluated the neuroprotective effects of 7,8-DHF in a transgenic ALS mouse model (SOD1(G93A)). We found that chronic administration of 7,8-DHF significantly improved motor deficits, and preserved spinal MNs count and dendritic spines in SOD1(G93A) mice. These data suggest that 7,8-DHF should be considered as a potential therapy for ALS and the other motor neuron diseases.
Assuntos
Esclerose Lateral Amiotrófica/tratamento farmacológico , Flavanonas/farmacologia , Neurônios Motores/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Receptor trkB/agonistas , Superóxido Dismutase/genética , Esclerose Lateral Amiotrófica/patologia , Esclerose Lateral Amiotrófica/fisiopatologia , Animais , Contagem de Células , Sobrevivência Celular/efeitos dos fármacos , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/patologia , Flavanonas/uso terapêutico , Humanos , Camundongos Transgênicos , Neurônios Motores/patologia , Destreza Motora/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologia , Superóxido Dismutase-1RESUMO
The pathological accumulation of the ß-amyloid protein (Aß) has been closely associated with synaptic loss and neurotoxicity contributing to cognitive dysfunction in Alzheimer's disease (AD). Oligomers of Aß42 appear to be the most neurotoxic form. Two of the most promising attempts to reduce Aß accumulation have been with scyllo-inositol, an inositol steroisomer, that stabilizes Aß42 peptide and prevents it from progressing to oligomers and fibrils and R-flurbiprofen, a purified enantiomer of the classical racemic non-steroidal anti-inflammatory drugs (NSAID), flurbiprofen, that retains the ability to specifically lower Aß42. In the present study we evaluated the effects of scyllo-inositol and the combination treatment of scyllo-inositol+R-flurbiprofen on amyloid pathology and hippocampal-dependent memory function in 5XFAD mice, a model of Aß pathology characterized by an enormous production of Aß42. Our expectations were that the combination treatment of scyllo-inositol+R-flurbiprofen would have an additive effect in preventing Aß accumulation and that cognition would be improved. Mice treated with scyllo-inositol exhibit 41 and 35% reduction in the deposition of the amyloid plaques stained by antibody against Aß42 and Aß40 respectively. Scyllo-inositol was not more effective when combined with R-flurbiprofen for the measures tested. Scyllo-inositol treated mice performed significantly better at the radial arm water maze (RAWM) task than untreated and scyllo-inositol+R-flurbiprofen treated mice.
Assuntos
Doença de Alzheimer/patologia , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Flurbiprofeno/administração & dosagem , Inositol/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Animais , Encéfalo/patologia , Cognição/efeitos dos fármacos , Modelos Animais de Doenças , Quimioterapia Combinada , Ensaio de Imunoadsorção Enzimática , Espectroscopia de Ressonância Magnética , Memória/efeitos dos fármacos , Camundongos , Camundongos TransgênicosRESUMO
We have previously reported that chronic ibuprofen treatment improves cognition and decreases intracellular Aß and phosphorylated-tau levels in 3xTg-AD mice. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) that independently of its anti-inflammatory effects has anti-amyloidogenic activity as a gamma-secretase modulator (GSM) and both activities have the potential to decrease Aß pathology. To further understand the effects of NSAIDs in 3xTg-AD mice, we treated 3xTg-AD mice with R-flurbiprofen, an enantiomer of the NSAID flurbiprofen that maintains the GSM activity but has greatly reduced anti-inflammatory activity, and analyzed its effect on cognition, Aß, tau, and the neurochemical profile of the hippocampus. Treatment with R-flurbiprofen from 5 to 7 months of age resulted in improved cognition on the radial arm water maze (RAWM) test and decreased the level of hyperphosphorylated tau immunostained with AT8 and PHF-1 antibodies. No significant changes in the level of Aß (using 6E10 and NU-1 antibodies) were detected. Using magnetic resonance spectroscopy (MRS) we found that R-flurbiprofen treatment decreased the elevated level of glutamine in 3xTg-AD mice down to the level detected in non-transgenic mice. Glutamine levels correlated with PHF-1 immunostained hyperphosphorylated tau. We also found an inverse correlation between the concentration of glutamate and learning across all the mice in the study. Glutamine and glutamate, neurochemicals that shuttles between neurons and astrocytes to maintain glutamate homeostasis in the synapses, deserve further attention as MR markers of cognitive function.