RESUMO
Motor-skill learning induces changes in synaptic structure and function in the primary motor cortex through the involvement of a long-term potentiation- (LTP-) like mechanism. Although there is evidence that calcium-dependent release of gliotransmitters by astrocytes plays an important role in synaptic transmission and plasticity, the role of astrocytes in motor-skill learning is not known. To test the hypothesis that astrocytic activity is necessary for motor-skill learning, we perturbed astrocytic function using pharmacological and genetic approaches. We find that perturbation of astrocytes either by selectively attenuating IP3R2 mediated astrocyte Ca(2+) signaling or using an astrocyte specific metabolic inhibitor fluorocitrate (FC) results in impaired motor-skill learning of a forelimb reaching-task in mice. Moreover, the learning impairment caused by blocking astrocytic activity using FC was rescued by administration of the gliotransmitter D-serine. The learning impairments are likely caused by impaired LTP as FC blocked LTP in slices and prevented motor-skill training-induced increases in synaptic AMPA-type glutamate receptor in vivo. These results support the conclusion that normal astrocytic Ca(2+) signaling during a reaching task is necessary for motor-skill learning.
Assuntos
Astrócitos/fisiologia , Aprendizagem/fisiologia , Destreza Motora/fisiologia , Animais , Antimetabólitos/farmacologia , Astrócitos/efeitos dos fármacos , Citratos/farmacologia , Antagonistas de Estrogênios/farmacologia , Membro Anterior , Técnicas In Vitro , Injeções Intraventriculares , Receptores de Inositol 1,4,5-Trifosfato/efeitos dos fármacos , Receptores de Inositol 1,4,5-Trifosfato/genética , Aprendizagem/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Destreza Motora/efeitos dos fármacos , Mutação , Desempenho Psicomotor/efeitos dos fármacos , Receptores de AMPA/efeitos dos fármacos , Serina/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Tamoxifeno/farmacologiaRESUMO
Decompressive craniectomy is often required after head trauma, stroke, or cranial bleeding to control subsequent brain swelling and prevent death. The infection rate after cranial bone flap replacement ranges from 0.8% to 15%, with an alarming frequency caused by methicillin-resistant Staphylococcus aureus, which is problematic because of recalcitrance to antibiotic therapy. Herein we report the establishment of a novel mouse model of S. aureus cranial bone flap infection that mimics several aspects of human disease. Bacteria colonized bone flaps for up to 4 months after infection, as revealed by scanning electron microscopy and quantitative culture, demonstrating the chronicity of the model. Analysis of a human cranial bone flap with confirmed S. aureus infection by scanning electron microscopy revealed similar structural attributes as the mouse model, demonstrating that it closely parallels structural facets of human disease. Inflammatory indices were most pronounced within the subcutaneous galeal compartment compared with the underlying brain parenchyma. Specifically, neutrophil influx and chemokine expression (CXCL2 and CCL5) were markedly elevated in the galea, which demonstrated substantial edema on magnetic resonance images, whereas the underlying brain parenchyma exhibited minimal involvement. Evaluation of immune mechanisms required for bacterial containment and inflammation revealed critical roles for MyD88-dependent signaling and neutrophils. This novel mouse model of cranial bone flap infection can be used to identify key immunologic and therapeutic mechanisms relevant to persistent bone flap infection in humans.
Assuntos
Imunidade Celular/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Retalhos Cirúrgicos/efeitos adversos , Infecção da Ferida Cirúrgica/imunologia , Animais , Encéfalo/imunologia , Quimiocinas/metabolismo , Modelos Animais de Doenças , Humanos , Inflamação/imunologia , Imageamento por Ressonância Magnética , Staphylococcus aureus Resistente à Meticilina/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Fator 88 de Diferenciação Mieloide/deficiência , Fator 88 de Diferenciação Mieloide/fisiologia , Neutrófilos/imunologia , Crânio , Infecções Estafilocócicas/diagnóstico , Retalhos Cirúrgicos/imunologia , Infecção da Ferida Cirúrgica/diagnósticoRESUMO
PURPOSE: To develop a tissue fixation method that preserves in vivo manganese enhancement for ex vivo magnetic resonance imaging (MRI). The needs are clear, as conventional in vivo manganese-enhanced MRI (MEMRI) applied to live animals is time-limited, hence limited in spatial resolution and signal-to-noise ratio (SNR). Ex vivo applications can achieve superior spatial resolution and SNR through increased signal averaging and optimized radiofrequency coil designs. A tissue fixation method that preserves in vivo Mn(2+) enhancement postmortem is necessary for ex vivo MEMRI. MATERIALS AND METHODS: T1 measurements and T1 -weighted MRI were performed on MnCl2 -administered mice. The mice were then euthanized and the brains were fixed using one of two brain tissue fixation methods: aldehyde solution or focused beam microwave irradiation (FBMI). MRI was then performed on the fixed brains. RESULTS: T1 values and T1 -weighted signal contrasts were comparable between in vivo and ex vivo scans on aldehyde-fixed brains. FBMI resulted in the loss of Mn(2+) enhancement. CONCLUSION: Aldehyde fixation, not FBMI, maintained in vivo manganese enhancement for ex vivo MEMRI.
Assuntos
Aldeídos , Química Encefálica/efeitos da radiação , Encéfalo/anatomia & histologia , Cloretos , Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/métodos , Compostos de Manganês , Fixação de Tecidos/métodos , Animais , Encéfalo/efeitos da radiação , Cloretos/química , Meios de Contraste/química , Fixadores , Compostos de Manganês/química , Camundongos , Camundongos SCID , Micro-Ondas , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Neuronal damage induced by ongoing human immunodeficiency virus type 1 (HIV-1) infection was investigated in humanized NOD/scid-IL-2Rγ(c)(null) mice transplanted at birth with human CD34-positive hematopoietic stem cells. Mice infected at 5 months of age and followed for up to 15 weeks maintained significant plasma viral loads and showed reduced numbers of CD4(+) T-cells. Prospective serial proton magnetic resonance spectroscopy tests showed selective reductions in cortical N-acetyl aspartate in infected animals. Diffusion tensor imaging revealed structural changes in cortical gray matter. Postmortem immunofluorescence brain tissue examinations for neuronal and glial markers, captured by multispectral imaging microscopy and quantified by morphometric and fluorescence emission, showed regional reduction of neuronal soma and synaptic architectures. This was evidenced by loss of microtubule-associated protein 2, synaptophysin, and neurofilament antigens. This study is the first, to our knowledge, demonstrating lost neuronal integrity after HIV-1 infection in humanized mice. As such, the model permits studies of the relationships between ongoing viral replication and virus-associated neurodegeneration.
Assuntos
Progressão da Doença , Infecções por HIV/patologia , HIV-1/imunologia , Rede Nervosa/patologia , Neurônios/patologia , Animais , Antígenos CD34/administração & dosagem , Antígenos CD34/biossíntese , Transtornos Cognitivos/imunologia , Transtornos Cognitivos/patologia , Infecções por HIV/imunologia , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Rede Nervosa/imunologia , Neuroglia/imunologia , Neuroglia/patologia , Neuroglia/virologia , Neurônios/imunologia , Neurônios/virologia , Estudos Prospectivos , Carga Viral/métodos , Replicação Viral/imunologiaRESUMO
[This corrects the article PMC10317193.].
RESUMO
Antiretroviral therapy (ART) restricts human immunodeficiency virus type one (HIV-1) replication and by so doing, improves the quality and longevity of life for infected people. Nonetheless, treatment can also lead to adverse clinical outcomes such as drug resistance and systemic adverse events. Both could be affected by long-acting slow effective release ART. Indeed, maintenance of sustained plasma drug levels, for weeks or months, after a single high-level dosing, could improve regimen adherence but, at the same time, affect systemic toxicities. Of these, the most troubling are those that affect the central nervous system (CNS). To address this, dolutegravir (Tivicay, DTG), a potent and durable HIV integrase inhibitor used effectively in combination ART was tested. Rodents were administered parenteral 45-mg/kg doses. DTG-associated changes in CNS homeostasis were assessed by measuring brain metabolic activities. After antiretroviral treatment, brain subregions were dissected and screened by mass spectrometry-based metabolomics. Metabolic drug-related dysregulation of energy and oxidative stress were readily observed within the cerebellum and frontal cortex following native drug administrations. Each was associated with alterations in neural homeostasis and depleted canonical oxidation protection pools that included glutathione and ascorbic acid. Surprisingly, the oxidative stress-related metabolites were completely attenuated when DTG was administered as nanoformulations. These data demonstrate the importance of formulation design in control of DTG or perhaps other antiretroviral drug-associated CNS events.
Assuntos
Antirretrovirais/farmacologia , Encéfalo/metabolismo , Encéfalo/patologia , Nanopartículas/química , Estresse Oxidativo , Animais , Encéfalo/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Injeções , Masculino , Metabolômica , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Oxazinas , Estresse Oxidativo/efeitos dos fármacos , Piperazinas , Piridonas , Espécies Reativas de Oxigênio/metabolismoRESUMO
Blood-borne macrophage ingress into brain in HIV-1 associated neurocognitive disorders governs the tempo of disease. We used superparamagnetic iron-oxide particles loaded into murine bone marrow-derived macrophages (BMM) injected intravenously into HIV-1 encephalitis mice to quantitatively assess BMM entry into diseased brain regions. Magnetic resonance imaging tests were validated by histological coregistration and enhanced image processing. The demonstration of robust BMM migration into areas of focal encephalitis provide 'proof of concept' for the use of MRI to monitor macrophage ingress into brain.
Assuntos
Barreira Hematoencefálica/fisiopatologia , Encefalite/etiologia , Encefalite/patologia , Infecções por HIV/complicações , Macrófagos/fisiologia , Animais , Barreira Hematoencefálica/patologia , Movimento Celular/fisiologia , Modelos Animais de Doenças , Encefalite/virologia , Proteína Glial Fibrilar Ácida/metabolismo , Imageamento Tridimensional , Macrófagos/patologia , Imageamento por Ressonância Magnética , Masculino , Camundongos , Camundongos SCID , Vimentina/metabolismoRESUMO
RATIONALE: Long-acting slow effective release antiretroviral therapy (LASER ART) was developed to improve patient regimen adherence, prevent new infections, and facilitate drug delivery to human immunodeficiency virus cell and tissue reservoirs. In an effort to facilitate LASER ART development, "multimodal imaging theranostic nanoprobes" were created. These allow combined bioimaging, drug pharmacokinetics and tissue biodistribution tests in animal models. METHODS: Europium (Eu3+)- doped cobalt ferrite (CF) dolutegravir (DTG)- loaded (EuCF-DTG) nanoparticles were synthesized then fully characterized based on their size, shape and stability. These were then used as platforms for nanoformulated drug biodistribution. RESULTS: Folic acid (FA) decoration of EuCF-DTG (FA-EuCF-DTG) nanoparticles facilitated macrophage targeting and sped drug entry across cell barriers. Macrophage uptake was higher for FA-EuCF-DTG than EuCF-DTG nanoparticles with relaxivities of r2 = 546 mM-1s-1 and r2 = 564 mM-1s-1 in saline, and r2 = 850 mM-1s-1 and r2 = 876 mM-1s-1 in cells, respectively. The values were ten or more times higher than what was observed for ultrasmall superparamagnetic iron oxide particles (r2 = 31.15 mM-1s-1 in saline) using identical iron concentrations. Drug particles were detected in macrophage Rab compartments by dual fluorescence labeling. Replicate particles elicited sustained antiretroviral responses. After parenteral injection of FA-EuCF-DTG and EuCF-DTG into rats and rhesus macaques, drug, iron and cobalt levels, measured by LC-MS/MS, magnetic resonance imaging, and ICP-MS were coordinate. CONCLUSION: We posit that these theranostic nanoprobes can assess LASER ART drug delivery and be used as part of a precision nanomedicine therapeutic strategy.
Assuntos
Imageamento por Ressonância Magnética/métodos , Imagem Multimodal/métodos , Nanomedicina Teranóstica/métodos , Animais , Sistemas de Liberação de Medicamentos/métodos , Európio/química , Európio/farmacocinética , Ácido Fólico/química , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Macaca mulatta , Macrófagos/metabolismo , Microscopia Confocal , Nanopartículas/química , Oxazinas , Piperazinas , PiridonasRESUMO
Nicotine dependence is defined by dopaminergic neuronal activation within the nucleus accumbens (ACB) and by affected neural projections from nicotine-stimulated neurons. Control of any subsequent neural activities would underpin any smoking cessation strategy. While extensive efforts have been made to study the pathophysiology of nicotine addiction, more limited works were developed to find imaging biomarkers. If such biomarkers are made available, addictive behaviors could be monitored noninvasively. To such ends, we employed manganese (Mn2+)-enhanced magnetic resonance imaging (MEMRI) to determine whether it could be used to monitor neuronal activities after acute and chronic nicotine exposure in rats. The following were observed. Mn2+ infusion identified ACB and hippocampal (HIP) neuronal activities following acute nicotine administration. Chronic exposure was achieved by week long subcutaneously implanted nicotine mini-pump. Here nicotine was shown to activate neurons in the ACB, HIP, and the prefrontal and insular cortex. These are all central nervous system reward regions linked to drug addiction. In conclusion, MEMRI is demonstrated to be a powerful imaging tool to study brain subregion specific neuronal activities affected by nicotine. Thus, we posit that MEMRI could be used to assess smoking-associated tolerance, withdrawal and as such serve as a pre-clinical screening tool for addiction cessation strategies in humans.
RESUMO
The size, shape and chemical composition of europium (Eu3+) cobalt ferrite (CFEu) nanoparticles were optimized for use as a "multimodal imaging nanoprobe" for combined fluorescence and magnetic resonance bioimaging. Doping Eu3+ ions into a CF structure imparts unique bioimaging and magnetic properties to the nanostructure that can be used for real-time screening of targeted nanoformulations for tissue biodistribution assessment. The CFEu nanoparticles (size â¼7.2nm) were prepared by solvothermal techniques and encapsulated into poloxamer 407-coated mesoporous silica (Si-P407) to form superparamagnetic monodisperse Si-CFEu nanoparticles with a size of â¼140nm. Folic acid (FA) nanoparticle decoration (FA-Si-CFEu, size â¼140nm) facilitated monocyte-derived macrophage (MDM) targeting. FA-Si-CFEu MDM uptake and retention was higher than seen with Si-CFEu nanoparticles. The transverse relaxivity of both Si-CFEu and FA-Si-CFEu particles were r2=433.42mM-1s-1 and r2=419.52mM-1s-1 (in saline) and r2=736.57mM-1s-1 and r2=814.41mM-1s-1 (in MDM), respectively. The results were greater than a log order-of-magnitude than what was observed at replicate iron concentrations for ultrasmall superparamagnetic iron oxide (USPIO) particles (r2=31.15mM-1s-1 in saline) and paralleled data sets obtained for T2 magnetic resonance imaging. We now provide a developmental opportunity to employ these novel particles for theranostic drug distribution and efficacy evaluations. STATEMENT OF SIGNIFICANCE: A novel europium (Eu3+) doped cobalt ferrite (Si-CFEu) nanoparticle was produced for use as a bioimaging probe. Its notable multifunctional, fluorescence and imaging properties, allows rapid screening of future drug biodistribution. Decoration of the Si-CFEu particles with folic acid increased its sensitivity and specificity for magnetic resonance imaging over a more conventional ultrasmall superparamagnetic iron oxide particles. The future use of these particles in theranostic tests will serve as a platform for designing improved drug delivery strategies to combat inflammatory and infectious diseases.
Assuntos
Cobalto/química , Európio/química , Compostos Férricos/química , Imageamento por Ressonância Magnética , Nanopartículas/química , Dióxido de Silício/química , Animais , Endocitose , Ácido Fólico/química , Humanos , Imuno-Histoquímica , Macrófagos/metabolismo , Macrófagos/ultraestrutura , Masculino , Microscopia de Força Atômica , Microscopia Confocal , Monócitos/citologia , Nanopartículas/toxicidade , Ratos Sprague-Dawley , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Distribuição TecidualRESUMO
Metal-free magnetic resonance imaging (MRI) agents could overcome the established toxicity associated with metal-based agents in some patient populations and enable new modes of functional MRI in vivo. Herein, we report nitroxide-functionalized brush-arm star polymer organic radical contrast agents (BASP-ORCAs) that overcome the low contrast and poor in vivo stability associated with nitroxide-based MRI contrast agents. As a consequence of their unique nanoarchitectures, BASP-ORCAs possess per-nitroxide transverse relaxivities up to â¼44-fold greater than common nitroxides, exceptional stability in highly reducing environments, and low toxicity. These features combine to provide for accumulation of a sufficient concentration of BASP-ORCA in murine subcutaneous tumors up to 20 h following systemic administration such that MRI contrast on par with metal-based agents is observed. BASP-ORCAs are, to our knowledge, the first nitroxide MRI contrast agents capable of tumor imaging over long time periods using clinical high-field 1H MRI techniques.
RESUMO
Nigrostriatal degeneration, the pathological hallmark of Parkinson's disease (PD), is mirrored by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication. MPTP-treated animals show the common behavioral, motor, and pathological features of human disease. We demonstrated previously that adoptive transfer of Copaxone (Cop-1) immune cells protected the nigrostriatal dopaminergic pathway in MPTP-intoxicated mice. Herein, we evaluated this protection by quantitative proton magnetic resonance spectroscopic imaging (1H MRSI). 1H MRSI performed in MPTP-treated mice demonstrated that N-acetyl aspartate (NAA) was significantly diminished in the substantia nigra pars compacta (SNpc) and striatum, regions most affected in human disease. When the same regions were coregistered with immunohistochemical stains for tyrosine hydroxylase, numbers of neuronal bodies and termini were similarly diminished. MPTP-intoxicated animals that received Cop-1 immune cells showed NAA levels, in the SNpc and striatum, nearly equivalent to PBS-treated animals. Moreover, adoptive transfer of immune cells from ovalbumin-immunized to MPTP-treated mice failed to alter NAA levels or protect dopaminergic neurons and their projections. These results demonstrate that 1H MRSI can evaluate dopaminergic degeneration and its protection by Cop-1 immunization strategies. Most importantly, the results provide a monitoring system to assess therapeutic outcomes for PD.
Assuntos
Transferência Adotiva , Ácido Aspártico/análogos & derivados , Corpo Estriado/química , Intoxicação por MPTP/terapia , Espectroscopia de Ressonância Magnética , Transtornos Parkinsonianos/terapia , Peptídeos/imunologia , Substância Negra/química , Subpopulações de Linfócitos T/transplante , Animais , Ácido Aspártico/análise , Contagem de Células , Cromatografia Líquida de Alta Pressão , Corpo Estriado/imunologia , Corpo Estriado/patologia , Dopamina/fisiologia , Acetato de Glatiramer , Imunização , Intoxicação por MPTP/metabolismo , Intoxicação por MPTP/patologia , Imageamento por Ressonância Magnética , Masculino , Camundongos , Microglia/fisiologia , Proteína Básica da Mielina/imunologia , Degeneração Neural/imunologia , Proteínas do Tecido Nervoso/análise , Ovalbumina/imunologia , Transtornos Parkinsonianos/metabolismo , Transtornos Parkinsonianos/patologia , Substância Negra/imunologia , Substância Negra/patologia , Subpopulações de Linfócitos T/imunologia , Tirosina 3-Mono-Oxigenase/análiseRESUMO
Neuroinflammatory processes play a significant role in the pathogenesis of Parkinson's disease (PD). Epidemiologic, animal, human, and therapeutic studies all support the presence of an neuroinflammatory cascade in disease. This is highlighted by the neurotoxic potential of microglia . In steady state, microglia serve to protect the nervous system by acting as debris scavengers, killers of microbial pathogens, and regulators of innate and adaptive immune responses. In neurodegenerative diseases, activated microglia affect neuronal injury and death through production of glutamate, pro-inflammatory factors, reactive oxygen species, quinolinic acid amongst others and by mobilization of adaptive immune responses and cell chemotaxis leading to transendothelial migration of immunocytes across the blood-brain barrier and perpetuation of neural damage. As disease progresses, inflammatory secretions engage neighboring glial cells, including astrocytes and endothelial cells, resulting in a vicious cycle of autocrine and paracrine amplification of inflammation perpetuating tissue injury. Such pathogenic processes contribute to neurodegeneration in PD. Research from others and our own laboratories seek to harness such inflammatory processes with the singular goal of developing therapeutic interventions that positively affect the tempo and progression of human disease.
RESUMO
PTEN-induced kinase 1 (PINK1) mutations are responsible for an autosomal recessive, familial form of Parkinson's disease. PINK1 protein is a Ser/Thr kinase localized to the mitochondrial membrane and is involved in many processes including mitochondrial trafficking, mitophagy, and proteasomal function. Using a new PINK1 knockout (PINK1 KO) rat model, we found altered brain metabolomic markers using magnetic resonance spectroscopy, identified changes in mitochondrial pathways with quantitative proteomics using sequential window acquisition of all theoretical spectra (SWATH) mass spectrometry, and demonstrated mitochondrial functional alterations through measurement of oxygen consumption and acidification rates. The observed alterations included reduced creatine, decreased levels of complex I of the electron transport chain, and increased proton leak in the electron transport chain in PINK1 KO rat brains. In conjunction, these results demonstrate metabolomic and mitochondrial alterations occur during the asymptomatic phase of Parkinson's disease in this model. These results indicate both potential early diagnostic markers and therapeutic pathways that can be used in PD.
Assuntos
Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Membranas Mitocondriais/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Proteínas Quinases/metabolismo , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Técnicas de Inativação de Genes , Mitocôndrias/genética , Doenças Mitocondriais/diagnóstico , Doença de Parkinson/diagnóstico , Proteínas Quinases/deficiência , RatosRESUMO
Neuroprotective immunity is defined by transformation of T-cell polarity for therapeutic gain. For neurodegenerative disorders and specifically for Parkinson's disease (PD), granulocyte-macrophage colony stimulating factor or vasoactive intestinal peptide receptor 2 (VIPR2) agonists elicit robust anti-inflammatory microglial responses leading to neuronal sparing in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. While neurotherapeutic potential was demonstrated for PD, there remain inherent limitations in translating these inventions from the laboratory to patients. One obstacle in translating such novel neurotherapeutics centers on the availability of suitable noninvasive methods to track disease progression and therapeutic efficacy. To this end, we developed manganese-enhanced magnetic resonance imaging (MEMRI) assays as a way to track a linkage between glial activation and VIPR2 agonist (LBT-3627)-induced neuroprotective immunity for MPTP-induced nigrostriatal degeneration. Notably, LBT-3627-treated, MPTP-intoxicated mice show reduced MEMRI brain signal intensities. These changes paralleled reduced astrogliosis and resulted in sparing of nigral tyrosine hydroxylase neurons. Most importantly, the data suggest that MEMRI can be developed as a biomarker tool to monitor neurotherapeutic responses that are relevant to common neurodegenerative disorders used to improve disease outcomes.
Assuntos
Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/métodos , Manganês/administração & dosagem , Oligopeptídeos/administração & dosagem , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/tratamento farmacológico , Receptores Tipo II de Peptídeo Intestinal Vasoativo/agonistas , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Microglia/metabolismo , Fármacos Neuroprotetores/administração & dosagem , Doença de Parkinson/imunologia , Transtornos Parkinsonianos/diagnóstico por imagem , Transtornos Parkinsonianos/tratamento farmacológico , Transtornos Parkinsonianos/imunologia , Proteínas Tirosina Quinases/metabolismoRESUMO
Progressive human immunodeficiency viral (HIV) infection commonly leads to a constellation of cognitive, motor, and behavioral impairments. These are collectively termed HIV-associated neurocognitive disorders (HAND). While antiretroviral therapy (ART) reduces HAND severity, it does not affect disease prevalence. Despite decades of research, there remain no biomarkers for HAND and all potential comorbid conditions must first be excluded for a diagnosis to be made. To this end, we now report that manganese (Mn(2+))-enhanced magnetic resonance imaging (MEMRI) can reflect brain region-specific HIV-1-induced neuropathology in chronically virus-infected NOD/scid-IL-2Rγc(null) humanized mice. MEMRI diagnostics mirrors the abilities of Mn(2+) to enter and accumulate in affected neurons during disease. T1 relaxivity and its weighted signal intensity are proportional to Mn(2+) activities in neurons. In 16-week virus-infected humanized mice, altered MEMRI signal enhancement was easily observed in affected brain regions. These included, but were not limited to, the hippocampus, amygdala, thalamus, globus pallidus, caudoputamen, substantia nigra, and cerebellum. MEMRI signal was coordinated with levels of HIV-1 infection, neuroinflammation (astro- and micro-gliosis), and neuronal injury. MEMRI accurately demonstrates the complexities of HIV-1-associated neuropathology in rodents that reflects, in measure, the clinical manifestations of neuroAIDS as it is seen in a human host.
Assuntos
Encéfalo/patologia , Encéfalo/virologia , Progressão da Doença , Infecções por HIV/diagnóstico , HIV-1/fisiologia , Imageamento por Ressonância Magnética , Manganês/química , Animais , Antígenos CD34/metabolismo , Hipocampo/patologia , Hipocampo/virologia , Humanos , Imuno-Histoquímica , Leucócitos/patologia , Camundongos , Modelos Biológicos , Processamento de Sinais Assistido por Computador , Fatores de TempoRESUMO
Strain specific mouse brain magnetic resonance imaging (MRI) atlases provide coordinate space linked anatomical registration. This allows longitudinal quantitative analyses of neuroanatomical volumes and imaging metrics for assessing the role played by aging and disease to the central nervous system. As NOD/scid-IL-2Rγ(c)(null) (NSG) mice allow human cell transplantation to study human disease, these animals are used to assess brain morphology. Manganese enhanced MRI (MEMRI) improves contrasts amongst brain components and as such can greatly help identifying a broad number of structures on MRI. To this end, NSG adult mouse brains were imaged in vivo on a 7.0 Tesla MR scanner at an isotropic resolution of 100 µm. A population averaged brain of 19 mice was generated using an iterative alignment algorithm. MEMRI provided sufficient contrast permitting 41 brain structures to be manually labeled. Volumes of 7 humanized mice brain structures were measured by atlas-based segmentation and compared against non-humanized controls. The humanized NSG mice brain volumes were smaller than controls (p < 0.001). Many brain structures of humanized mice were significantly smaller than controls. We posit that the irradiation and cell grafting involved in the creation of humanized mice were responsible for the morphological differences. Six NSG mice without MnCl2 administration were scanned with high resolution T2-weighted MRI and segmented to test broad utility of the atlas.
Assuntos
Anatomia Artística , Atlas como Assunto , Encéfalo/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Modelos Animais , Algoritmos , Animais , Meios de Contraste , Transplante de Células-Tronco Hematopoéticas , Humanos , Masculino , Manganês , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCIDRESUMO
Pancreatic cancer (PC) is one of the most aggressive malignancies due to intense desmoplasia, extreme hypoxia and inherent chemoresistance. Studies have implicated the expression of chemokine receptor CXCR4 and nuclear receptor co-activator-3 (NCOA3) in the development of desmoplasia and metastatic spread of PC. Using a series of polymeric CXCR4 antagonists (PCX), we optimized formulation of PCX/siNCOA3 polyplexes to simultaneously target CXCR4 and NCOA3 in PC. Cholesterol-modified PCX showed maximum CXCR4 antagonism, NCOA3 silencing and inhibition of PC cell migration in vitro. The optimized PCX/siNCOA3 polyplexes were used in evaluating antitumor and antimetastatic activity in orthotopic mouse model of metastatic PC. The polyplexes displayed significant inhibition of primary tumor growth, which was accompanied by a decrease in tumor necrosis and increased tumor perfusion. The polyplexes also showed significant antimetastatic effect and effective suppression of metastasis to distant organs. Overall, dual-function PCX/siNCOA3 polyplexes can effectively regulate tumor microenvironment to decrease progression and dissemination of PC.
Assuntos
Metástase Neoplásica/prevenção & controle , Coativador 3 de Receptor Nuclear/antagonistas & inibidores , Neoplasias Pancreáticas/terapia , Polímeros/uso terapêutico , RNA Interferente Pequeno/uso terapêutico , Receptores CXCR4/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Progressão da Doença , Feminino , Humanos , Camundongos Nus , Metástase Neoplásica/genética , Metástase Neoplásica/patologia , Coativador 3 de Receptor Nuclear/genética , Pâncreas/metabolismo , Pâncreas/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Polímeros/administração & dosagem , Polímeros/química , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/genéticaRESUMO
We describe age-related molecular and neuronal changes that disrupt mobility or energy balance based on brain region and genetic background. Compared to young mice, aged C57BL/6 mice exhibit marked locomotor (but not energy balance) impairments. In contrast, aged BALB mice exhibit marked energy balance (but not locomotor) impairments. Age-related changes in cerebellar or hypothalamic gene expression accompany these phenotypes. Aging evokes upregulation of immune pattern recognition receptors and cell adhesion molecules. However, these changes do not localize to microglia, the major CNS immunocyte. Consistent with a neuronal role, there is a marked age-related increase in excitatory synapses over the cerebellum and hypothalamus. Functional imaging of these regions is consistent with age-related synaptic impairments. These studies suggest that aging reactivates a developmental program employed during embryogenesis where immune molecules guide synapse formation and pruning. Renewed activity in this program may disrupt excitatory neurotransmission, causing significant behavioral deficits.
Assuntos
Envelhecimento/fisiologia , Cerebelo/fisiologia , Aminoácidos Excitatórios/fisiologia , Hipotálamo/fisiologia , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Envelhecimento/genética , Envelhecimento/imunologia , Animais , Metabolismo Energético/fisiologia , Expressão Gênica , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Atividade Motora/fisiologiaRESUMO
Brain function is highly dependent upon controlled energy metabolism whose loss heralds cognitive impairments. This is particularly notable in the aged individuals and in age-related neurodegenerative diseases. However, how metabolic homeostasis is disrupted in the aging brain is still poorly understood. Here we performed global, metabolomic and proteomic analyses across different anatomical regions of mouse brain at different stages of its adult lifespan. Interestingly, while severe proteomic imbalance was absent, global-untargeted metabolomics revealed an energymetabolic drift or significant imbalance in core metabolite levels in aged mouse brains. Metabolic imbalance was characterized by compromised cellular energy status (NAD decline, increased AMP/ATP, purine/pyrimidine accumulation) and significantly altered oxidative phosphorylation and nucleotide biosynthesis and degradation. The central energy metabolic drift suggests a failure of the cellular machinery to restore metabostasis (metabolite homeostasis) in the aged brain and therefore an inability to respond properly to external stimuli, likely driving the alterations in signaling activity and thus in neuronal function and communication.