RESUMO
Various oligomeric species of amyloid-beta have been proposed to play different immunogenic roles in the cellular pathology of Alzheimer's Disease. The dynamic interconversion between various amyloid oligomers and fibrillar assemblies makes it difficult to elucidate the role each potential aggregation state may play in driving neuroinflammatory and neurodegenerative pathology. The ability to identify the amyloid species that are key and essential drivers of these pathological hallmarks of Alzheimer's Disease is of fundamental importance for also understanding downstream events including tauopathies that mediate neuroinflammation with neurologic deficits. Here, we report the design and construction of a quantum dot mimetic for larger spherical oligomeric amyloid species as an "endogenously" fluorescent proxy for this cytotoxic assembly of amyloid to investigate its role in inducing inflammatory and stress response states in neuronal and glial cell types. The design parameters and construction protocol developed here may be adapted for developing quantum dot nano-bio assemblies for other biological systems of interest, particularly neurodegenerative diseases involving other protein aggregates.
Assuntos
COVID-19 , SARS-CoV-2 , Sinapses , Humanos , COVID-19/virologia , SARS-CoV-2/genética , Sinapses/fisiologia , AnimaisRESUMO
OBJECTIVE: To determine the long-term outcomes, including mortality and recurrent seizures, among children living with HIV (CLWH) who present with new onset seizure. METHODS: Zambian CLWH and new onset seizure were enrolled prospectively to determine the risk of and risk factors for recurrent seizures. Demographic data, clinical profiles, index seizure etiology, and 30-day mortality outcomes were previously reported. After discharge, children were followed quarterly to identify recurrent seizures and death. Given the high risk of early death, risk factors for recurrent seizure were evaluated using a model that adjusted for mortality. RESULTS: Among 73 children enrolled, 28 died (38%), 22 within 30-days of the index seizure. Median follow-up was 533 days (IQR 18-957) with 5% (4/73) lost to follow-up. Seizure recurrence was 19% among the entire cohort. Among children surviving at least 30-days after the index seizure, 27% had a recurrent seizure. Median time from index seizure to recurrent seizure was 161 days (IQR 86-269). Central nervous system opportunistic infection (CNS OI), as the cause for the index seizure was protective against recurrent seizures and higher functional status was a risk factor for seizure recurrence. SIGNIFICANCE: Among CLWH presenting with new onset seizure, mortality risks remain elevated beyond the acute illness period. Recurrent seizures are common and are more likely in children with higher level of functioning even after adjusting for the outcome of death. Newer antiseizure medications appropriate for co-usage with antiretroviral therapies are needed for the care of these children. CNS OI may represent a potentially reversible provocation for the index seizure, while seizures in high functioning CLWH without a CNS OI may be the result of a prior brain injury or susceptibility to seizures unrelated to HIV and thus represent an ongoing predisposition to seizures. PLAIN LANGUAGE SUMMARY: This study followed CLWH who experienced a new onset seizure to find out how many go on to have more seizures and identify any patient characteristics associated with having more seizures. The study found that mortality rates continue to be high beyond the acute clinical presentation with new onset seizure. Children with a CNS OI causing the new onset seizure had a lower risk of later seizures, possibly because the trigger for the seizure can be treated. In contrast, high functioning children without a CNS OI were at higher risk of future seizures.
Assuntos
Epilepsia Generalizada , Infecções por HIV , Criança , Humanos , Anticonvulsivantes/uso terapêutico , Estudos de Coortes , Convulsões/tratamento farmacológico , Epilepsia Generalizada/tratamento farmacológico , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Dano Encefálico Crônico/induzido quimicamente , Dano Encefálico Crônico/complicações , Dano Encefálico Crônico/tratamento farmacológicoRESUMO
BACKGROUND: Seizures are relatively common among children with HIV in low- and middle-income countries and are associated with significant morbidity and mortality. Early treatment with antiretroviral therapy (ART) may reduce this risk by decreasing rates of central nervous system infections and HIV encephalopathy. METHODS: We conducted a prospective, unmatched case-control study. We enrolled children with new-onset seizure from University Teaching Hospital in Lusaka, Zambia and 2 regional hospitals in rural Zambia. Controls were children with HIV and no history of seizures. Recruitment took place from 2016 to 2019. Early treatment was defined as initiation of ART before 12 months of age, at a CD4 percentage >15% in children aged 12-60 months or a CD4 count >350 cells/mm 3 for children aged 60 months or older. Logistic regression models were used to evaluate the association between potential risk factors and seizures. RESULTS: We identified 73 children with new-onset seizure and compared them with 254 control children with HIV but no seizures. Early treatment with ART was associated with a significant reduction in the odds of seizures [odds ratio (OR) 0.04, 95% confidence interval: 0.02 to 0.09; P < 0.001]. Having an undetectable viral load at the time of enrollment was strongly protective against seizures (OR 0.03, P < 0.001), whereas history of World Health Organization Stage 4 disease (OR 2.2, P = 0.05) or CD4 count <200 cells/mm 3 (OR 3.6, P < 0.001) increased risk of seizures. CONCLUSIONS: Early initiation of ART and successful viral suppression would likely reduce much of the excess seizure burden in children with HIV.
Assuntos
Fármacos Anti-HIV , Infecções por HIV , Criança , Humanos , Lactente , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Zâmbia/epidemiologia , Estudos de Casos e Controles , Fatores de Risco , Convulsões/tratamento farmacológico , Convulsões/prevenção & controle , Convulsões/complicações , Contagem de Linfócito CD4 , Fármacos Anti-HIV/uso terapêuticoRESUMO
Background: Links between acute lung injury (ALI), infectious disease, and neurological outcomes have been frequently discussed over the past few years, especially due to the COVID-19 pandemic. Yet, much of the cross-communication between organs, particularly the lung and the brain, has been understudied. Here, we have focused on the role of neutrophils in driving changes to the brain endothelium with ensuing microglial activation and neuronal loss in a model of ALI. Methods: We have applied a three-dose paradigm of 10µg/40µl intranasal lipopolysaccharide (LPS) to induce neutrophilia accompanied by proteinaceous exudate in bronchoalveolar lavage fluid (BALF) in adult C57BL/6 mice. Brain endothelial markers, microglial activation, and neuronal cytoarchitecture were evaluated 24hr after the last intranasal dose of LPS or saline. C57BL/6-Ly6g(tm2621(Cre-tdTomato)Arte (Catchup mice) were used to measure neutrophil and blood-brain barrier permeability following LPS exposure with intravital 2-photon imaging. Results: Three doses of intranasal LPS induced robust neutrophilia accompanied by proteinaceous exudate in BALF. ALI triggered central nervous system pathology as highlighted by robust activation of the cerebrovascular endothelium (VCAM1, CD31), accumulation of plasma protein (fibrinogen), microglial activation (IBA1, CD68), and decreased expression of proteins associated with postsynaptic terminals (PSD-95) in the hippocampal stratum lacunosum moleculare, a relay station between the entorhinal cortex and CA1 of the hippocampus. 2-photon imaging of Catchup mice revealed neutrophil homing to the cerebral endothelium in the blood-brain barrier and neutrophil extravasation from cerebral vasculature 24hr after the last intranasal treatment. Conclusions: Overall, these data demonstrate ensuing brain pathology resulting from ALI, highlighting a key role for neutrophils in driving brain endothelial changes and subsequent neuroinflammation. This paradigm may have a considerable translational impact on understanding how infectious disease with ALI can lead to neurodegeneration, particularly in the elderly.
RESUMO
Background: Links between acute lung injury (ALI), infectious disease, and neurological outcomes have been frequently discussed over the past few years, especially due to the COVID-19 pandemic. Yet, much of the cross-communication between organs, particularly the lung and the brain, has been understudied. Here, we have focused on the role of neutrophils in driving changes to the brain endothelium with ensuing microglial activation and neuronal loss in a model of ALI. Methods: We have applied a three-dose paradigm of 10µg/40µl intranasal lipopolysaccharide (LPS) to induce neutrophilia accompanied by proteinaceous exudate in bronchoalveolar lavage fluid (BALF) in adult C57BL/6 mice. Brain endothelial markers, microglial activation, and neuronal cytoarchitecture were evaluated 24hr after the last intranasal dose of LPS or saline. C57BL/6-Ly6g(tm2621(Cre-tdTomato)Arte (Catchup mice) were used to measure neutrophil and blood-brain barrier permeability following LPS exposure with intravital 2-photon imaging. Results: Three doses of intranasal LPS induced robust neutrophilia accompanied by proteinaceous exudate in BALF. ALI triggered central nervous system pathology as highlighted by robust activation of the cerebrovascular endothelium (VCAM1, CD31), accumulation of plasma protein (fibrinogen), microglial activation (IBA1, CD68), and decreased expression of proteins associated with postsynaptic terminals (PSD-95) in the hippocampal stratum lacunosum moleculare, a relay station between the entorhinal cortex and CA1 of the hippocampus. 2-photon imaging of Catchup mice revealed neutrophil homing to the cerebral endothelium in the blood-brain barrier and neutrophil extravasation from cerebral vasculature 24hr after the last intranasal treatment. Conclusions: Overall, these data demonstrate ensuing brain pathology resulting from ALI, highlighting a key role for neutrophils in driving brain endothelial changes and subsequent neuroinflammation. This paradigm may have a considerable translational impact on understanding how infectious disease with ALI can lead to neurodegeneration, particularly in the elderly.
RESUMO
Various oligomeric species of amyloid-beta have been proposed to play different immunogenic roles in the cellular pathology of Alzheimer's Disease. However, investigating the role of a homogenous single oligomeric species has been difficult due to highly dynamic oligomerization and fibril formation kinetics that convert between many species. Here we report the design and construction of a quantum dot mimetic for larger spherical oligomeric amyloid species as an "endogenously" fluorescent proxy for this cytotoxic species to investigate its role in inducing inflammatory and stress response states in neuronal and glial cell types.
RESUMO
Despite limited evidence for infection of SARS-CoV-2 in the central nervous system, cognitive impairment is a common complication reported in "recovered" COVID-19 patients. Identification of the origins of these neurological impairments is essential to inform therapeutic designs against them. However, such studies are limited, in part, by the current status of high-fidelity probes to visually investigate the effects of SARS-CoV-2 on the system of blood vessels and nerve cells in the brain, called the neurovascular unit. Here, we report that nanocrystal quantum dot micelles decorated with spike protein (COVID-QDs) are able to interrogate neurological damage due to SARS-CoV-2. In a transwell co-culture model of the neurovascular unit, exposure of brain endothelial cells to COVID-QDs elicited an inflammatory response in neurons and astrocytes without direct interaction with the COVID-QDs. These results provide compelling evidence of an inflammatory response without direct exposure to SARS-CoV-2-like nanoparticles. Additionally, we found that pretreatment with a neuro-protective molecule prevented endothelial cell damage resulting in substantial neurological protection. These results will accelerate studies into the mechanisms by which SARS-CoV-2 mediates neurologic dysfunction.
RESUMO
Systemic perturbations can drive a neuroimmune cascade after surgical trauma, including affecting the blood-brain barrier (BBB), activating microglia, and contributing to cognitive deficits such as delirium. Delirium superimposed on dementia (DSD) is a particularly debilitating complication that renders the brain further vulnerable to neuroinflammation and neurodegeneration, albeit these molecular mechanisms remain poorly understood. Here, we have used an orthopedic model of tibial fracture/fixation in APPSwDI/mNos2-/- AD (CVN-AD) mice to investigate relevant pathogenetic mechanisms underlying DSD. We conducted the present study in 6-month-old CVN-AD mice, an age at which we speculated amyloid-ß pathology had not saturated BBB and neuroimmune functioning. We found that URMC-099, our brain-penetrant anti-inflammatory neuroprotective drug, prevented inflammatory endothelial activation, breakdown of the BBB, synapse loss, and microglial activation in our DSD model. Taken together, our data link post-surgical endothelial activation, microglial MafB immunoreactivity, and synapse loss as key substrates for DSD, all of which can be prevented by URMC-099.
Assuntos
Delírio , Demência , Animais , Delírio/complicações , Delírio/prevenção & controle , Demência/etiologia , Demência/prevenção & controle , Hipocampo/metabolismo , Camundongos , Piridinas , Pirróis/uso terapêuticoRESUMO
Involvement of extracellular matrix (ECM) components in aging and age-related neurodegeneration is not well understood. The role of hyaluronan (HA), a major extracellular matrix glycosaminoglycan, in malignancy and inflammation is gaining new understanding. In particular, the differential biological effects of high molecular weight (HMW-HA) and low molecular weight hyaluronan (LMW-HA), and the mechanism behind such differences are being uncovered. Tightly regulated in the brain, HA can have diverse effects on cellular development, growth and degeneration. In this review, we summarize the homeostasis and signaling of HA in healthy tissue, discuss its distribution and ontogeny in the central nervous system (CNS), summarize evidence for its involvement in age-related neurodegeneration and Alzheimer Disease (AD), and assess the potential of HA as a therapeutic target in the CNS.
Assuntos
Receptores de Hialuronatos , Ácido Hialurônico , Envelhecimento , Sistema Nervoso Central , Humanos , Peso MolecularRESUMO
Microglia experience dramatic molecular and functional changes when transferred from the central nervous system (CNS) to a cell culture environment. Investigators largely attribute these findings to the loss of CNS-specific microenvironmental cues that dictate the gene-regulatory networks specified by master regulator transcription factors such as V-maf musculoaponeurotic fibrosarcoma oncogene homolog B (MafB). MafB regulates macrophage differentiation and activation by activating or repressing target genes critical to these processes. Here, we show that basal MafB levels in the BV-2 microglial cell line depend on the availability of lipids in the cell culture environment. Depletion of lipids, either by serum deprivation or the use of lipid-depleted serum, reduced MafB protein levels in BV-2 cells. Using live imaging, we also observed the engulfment of apoptotic BV-2 cell debris by neighboring BV-2 cells, highlighting an additional potential source of lipids in the cell culture environment. This observation was supported by experiments showing reduced MafB protein levels in BV-2 cells cultured with various phagocytosis inhibitors (cytochalasin D, annexin V) and reduced BV-2 cell phagocytic activity with serum deprivation. In aggregate, our data suggest that serum exposure regulates the transcription factor MafB in BV-2 cells through direct and indirect mechanisms.
RESUMO
The Sez6 family consists of Sez6, Sez6L, and Sez6L2. Its members are expressed throughout the brain and have been shown to influence synapse numbers and dendritic morphology. They are also linked to various neurological and psychiatric disorders. All Sez6 family members contain 2-3 CUB domains and 5 complement control protein (CCP) domains, suggesting that they may be involved in complement regulation. We show that Sez6 family members inhibit C3b/iC3b opsonization by the classical and alternative pathways with varying degrees of efficacy. For the classical pathway, Sez6 is a strong inhibitor, Sez6L2 is a moderate inhibitor, and Sez6L is a weak inhibitor. For the alternative pathway, the complement inhibitory activity of Sez6, Sez6L, and Sez6L2 all equaled or exceeded the activity of the known complement regulator MCP. Using Sez6L2 as the representative family member, we show that it specifically accelerates the dissociation of C3 convertases. Sez6L2 also functions as a cofactor for Factor I to facilitate the cleavage of C3b; however, Sez6L2 has no cofactor activity toward C4b. In summary, the Sez6 family are novel complement regulators that inhibit C3 convertases and promote C3b degradation.
Assuntos
Convertases de Complemento C3-C5/metabolismo , Complemento C3b/imunologia , Fibrinogênio/metabolismo , Proteínas de Membrana/metabolismo , Complemento C3b/metabolismo , Proteínas Inativadoras do Complemento/genética , Proteínas Inativadoras do Complemento/metabolismo , Via Alternativa do Complemento/efeitos dos fármacos , Via Clássica do Complemento/efeitos dos fármacos , Expressão Gênica , Humanos , Imuno-Histoquímica , Proteínas de Membrana/genética , Proteínas de Membrana/farmacologia , Proteólise , Proteínas Recombinantes de FusãoRESUMO
Colloidal semiconductor quantum dots (QDs) have long established their versatility and utility for the visualization of biological interactions. On the single-particle level, QDs have demonstrated superior photophysical properties compared to organic dye molecules or fluorescent proteins, but it remains an open question as to which of these fundamental characteristics are most significant with respect to the performance of QDs for imaging beyond the diffraction limit. Here, we demonstrate significant enhancement in achievable localization precision in QD-labeled neurons compared to neurons labeled with an organic fluorophore. Additionally, we identify key photophysical parameters of QDs responsible for this enhancement and compare these parameters to reported values for commonly used fluorophores for super-resolution imaging.
Assuntos
Pontos Quânticos , Corantes Fluorescentes , Microscopia de Fluorescência , Semicondutores , Imagem Individual de MoléculaRESUMO
Mordes et al. (2020) did not detect the survival or motor phenotypes in C9orf72 BAC transgenic mice originally described by Liu et al. (2016). We discuss methodological differences between the Mordes and Liu studies, several additional studies in which survival and motor phenotypes were found, and possible environmental and genetic effects. First, Nguyen et al. (2020) showed robust ALS/FTD phenotypes in C9-BAC versus non-transgenic (NT) mice and that α-GA1 treatment improved survival, behavior, and neurodegeneration. The groups of Gelbard and Saxena also show decreased survival of C9-BAC versus NT mice and neuropathological and behavioral deficits similar to those shown by Liu et al. (2016). Although FVB/N mice can have seizures, increases in seizure severity and death of C9 and NT animals, which may mask C9 disease phenotypes, have been observed in recent C9-500 FVB/NJ-bred cohorts. In summary, we provide an update on phenotypes seen in FVB C9-BAC mice and additional details to successfully use this model. This Matters Arising Response paper addresses the Mordes et al. (2020) Matters Arising paper, published concurrently in Neuron.
Assuntos
Esclerose Lateral Amiotrófica , Demência Frontotemporal , Esclerose Lateral Amiotrófica/genética , Animais , Proteína C9orf72/genética , Expansão das Repetições de DNA , Modelos Animais de Doenças , Demência Frontotemporal/genética , Camundongos , Camundongos Transgênicos , FenótipoRESUMO
OBJECTIVE: Interactions between enzyme-inducing anti-seizure medications (EI-ASMs) and antiretroviral drugs (ARVs) can lead to decreased ARV levels and may increase the likelihood of viral resistance. We conducted a study to determine if co-usage of ARVs and EI-ASMs is associated with ARV-resistant human immunodeficiency virus (HIV) among people living with HIV in Zambia. METHODS: Eligible participants were ≥18 years of age and concurrently taking ASMs and ARVs for at least 1 month of the prior 6-month period. Data were obtained regarding medication and HIV history. CD4 counts, plasma viral loads (pVLs), and HIV genotype and resistance profile in participants with a pVL >1000 copies/mL were obtained. Pearson's test of independence was used to determine whether treatment with EI-ASM was associated with pVL >1000/mL copies. RESULTS: Of 50 participants, 41 (82%) were taking carbamazepine (37 on monotherapy), and all had stable regimens in the prior 6 months. Among the 13 ARV regimens used, 68% had a tenofovir/lamivudine backbone. The majority (94%) were on a stable ARV regimen for >6 months. Median CD4 nadir was 205 cells/mm3 (interquartile range [IQR] 88-389), and 60% of participants had commenced ARV treatment before advanced disease occurred. Mean CD4 count at enrollment was 464 cells/mm3 (SD 226.3). Seven participants (14%) had a CD4 count <200 cells/mm3 . Four (8%) had a pVL >1000 copies/mL; all were on carbamazepine. Three participants with elevated pVL had a CD4 count <200 cells/mm3 . None had documented adherence concerns by providers; however, two had events concerning for clinical failure. HIV genotype testing showed mutations in three participants. Carbamazepine was not found to correlate with elevated pVL (P = .58). SIGNIFICANCE: EI-ASMs are commonly used in sub-Saharan Africa. Despite concurrent use of EI-ASMs and ARVs, the majority of participants showed CD4 counts >200 cells/mm3 and were virally suppressed. Carbamazepine was not associated with an increased risk of virological failure or ARV-resistant HIV.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Anticonvulsivantes/uso terapêutico , Carbamazepina/uso terapêutico , Epilepsia/tratamento farmacológico , Infecções por HIV/tratamento farmacológico , Adulto , Instituições de Assistência Ambulatorial/estatística & dados numéricos , Fármacos Anti-HIV/efeitos adversos , Anticonvulsivantes/efeitos adversos , Contagem de Linfócito CD4 , Carbamazepina/efeitos adversos , Interações Medicamentosas , Farmacorresistência Viral , Epilepsia/complicações , Feminino , Infecções por HIV/complicações , Humanos , Masculino , Resultado do Tratamento , Carga Viral/efeitos dos fármacos , ZâmbiaRESUMO
Brain functioning and high-order cognitive functions critically rely on glucose as a metabolic substrate. In a recent study, Kealy et al. investigated the impact of glucose availability on sickness behavior and delirium in mice and humans. They identified disrupted brain carbohydrate metabolism as a key mechanistic driver of these behaviors.
Assuntos
Delírio , Glucose , Animais , Encéfalo , Cognição , Metabolismo Energético , Humanos , Inflamação , CamundongosRESUMO
OBJECTIVE: The present work evaluates the relationship between postoperative immune and neurovascular changes and the pathogenesis of surgery-induced delirium superimposed on dementia. BACKGROUND AND RATIONALE: Postoperative delirium is a common complication in many older adults and in patients with dementia including Alzheimer's disease (AD). The course of delirium can be particularly debilitating, while its pathophysiology remains poorly defined. HISTORICAL EVOLUTION: As of 2019, an estimated 5.8 million people of all ages have been diagnosed with AD, 97% of whom are >65 years of age. Each year, many of these patients require surgery. However, anesthesia and surgery can increase the risk for further cognitive decline. Surgery triggers neuroinflammation both in animal models and in humans, and a failure to resolve this inflammatory state may contribute to perioperative neurocognitive disorders as well as neurodegenerative pathology. UPDATED HYPOTHESIS: We propose an immunovascular hypothesis whereby dysregulated innate immunity negatively affects the blood-brain interface, which triggers delirium and thereby exacerbates AD neuropathology. EARLY EXPERIMENTAL DATA: We have developed a translational model to study delirium superimposed on dementia in APPSwDI/mNos2-/- AD mice (CVN-AD) after orthopedic surgery. At 12 months of age, CVN-AD showed distinct neuroimmune and vascular impairments after surgery, including acute microgliosis and amyloid-ß deposition. These changes correlated with attention deficits, a core feature of delirium-like behavior. FUTURE EXPERIMENTS AND VALIDATION STUDIES: Future research should determine the extent to which prevention of surgery-induced microgliosis and/or neurovascular unit dysfunction can prevent or ameliorate postoperative memory and attention deficits in animal models. Translational human studies should evaluate perioperative indices of innate immunity and neurovascular integrity and assess their potential link to perioperative neurocognitive disorders. MAJOR CHALLENGES FOR THE HYPOTHESIS: Understanding the complex relationships between delirium and dementia will require mechanistic studies aimed at evaluating the role of postoperative neuroinflammation and blood-brain barrier changes in the setting of pre-existing neurodegenerative and/or aging-related pathology. LINKAGE TO OTHER MAJOR THEORIES: Non-resolving inflammation with vascular disease that leads to cognitive impairments and dementia is increasingly important in risk stratification for AD in the aging population. The interdependence of these factors with surgery-induced neuroinflammation and cognitive dysfunction is also becoming apparent, providing a strong platform for assessing the relationship between postoperative delirium and longer term cognitive dysfunction in older adults.
Assuntos
Delírio/fisiopatologia , Demência/complicações , Inflamação , Complicações Pós-Operatórias , Animais , Barreira Hematoencefálica , Encéfalo/patologia , Transtornos Cognitivos/etiologia , Modelos Animais de Doenças , Humanos , Camundongos , Transtornos NeurocognitivosRESUMO
Multiple sclerosis (MS) is an inflammatory, neurodegenerative disease of the CNS characterized by both grey and white matter injury. Microglial activation and a reduction in synaptic density are key features of grey matter pathology that can be modeled with MOG35-55 experimental autoimmune encephalomyelitis (EAE). Complement deposition combined with microglial engulfment has been shown during normal development and in disease as a mechanism for pruning synapses. We tested whether there is excess complement production in the EAE hippocampus and whether complement-dependent synapse loss is a source of degeneration in EAE using C1qa and C3 knockout mice. We found that C1q and C3 protein and mRNA levels were elevated in EAE mice. Genetic loss of C3 protected mice from EAE-induced synapse loss, reduced microglial activation, decreased the severity of the EAE clinical score, and protected memory/freezing behavior after contextual fear conditioning. C1qa KO mice with EAE showed little to no change on these measurements compared to WT EAE mice. Thus, pathologic expression and activation of the early complement pathway, specifically at the level of C3, contributes to hippocampal grey matter pathology in the EAE.
Assuntos
Encefalomielite Autoimune Experimental , Esclerose Múltipla , Doenças Neurodegenerativas , Animais , Camundongos , Camundongos Endogâmicos C57BL , SinapsesAssuntos
Isquemia Encefálica , Varicela , Herpes Zoster , Acidente Vascular Cerebral , Herpesvirus Humano 3 , HumanosRESUMO
BACKGROUND: Patients with pre-existing neurodegenerative disease commonly experience fractures that require orthopedic surgery. Perioperative neurocognitive disorders (PND), including delirium and postoperative cognitive dysfunction, are serious complications that can result in increased 1-year mortality when superimposed on dementia. Importantly, there are no disease-modifying therapeutic options for PND. Our lab developed the "broad spectrum" mixed-lineage kinase 3 inhibitor URMC-099 to inhibit pathological innate immune responses that underlie neuroinflammation-associated cognitive dysfunction. Here, we test the hypothesis that URMC-099 can prevent surgery-induced neuroinflammation and cognitive impairment. METHODS: Orthopedic surgery was performed by fracturing the tibia of the left hindlimb with intramedullary fixation under general anesthesia and analgesia. In a pilot experiment, 9-month-old mice were treated five times with URMC-099 (10 mg/kg, i.p.), spaced 12 h apart, with three doses prior to surgery and two doses following surgery. In this experiment, microgliosis was evaluated using unbiased stereology and blood-brain barrier (BBB) permeability was assessed using immunoglobulin G (IgG) immunostaining. In follow-up experiments, 3-month-old mice were treated only three times with URMC-099 (10 mg/kg, i.p.), spaced 12 h apart, prior to orthopedic surgery. Two-photon scanning laser microscopy and CLARITY with light-sheet microscopy were used to define surgery-induced changes in microglial dynamics and morphology, respectively. Surgery-induced memory impairment was assessed using the "What-Where-When" and Memory Load Object Discrimination tasks. The acute peripheral immune response to surgery was assessed by cytokine/chemokine profiling and flow cytometry. Finally, long-term fracture healing was assessed in fracture callouses using micro-computerized tomography (microCT) and histomorphometry analyses. RESULTS: Orthopedic surgery induced BBB disruption and microglial activation, but had no effect on microglial process motility. Surgically treated mice exhibited impaired object place and identity discrimination in the "What-Where-When" and Memory Load Object Discrimination tasks. Both URMC-099 dosing paradigms prevented the neuroinflammatory sequelae that accompanied orthopedic surgery. URMC-099 prophylaxis had no effect on the mobilization of the peripheral innate immune response and fracture healing. CONCLUSIONS: These findings show that prophylactic URMC-099 treatment is sufficient to prevent surgery-induced microgliosis and cognitive impairment without affecting fracture healing. Together, these findings provide compelling evidence for the advancement of URMC-099 as a therapeutic option for PND.