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New in vitro models provide an exciting opportunity to study live human microglia. Previously, a major limitation in understanding human microglia in health and disease has been their limited availability. Here, we provide an overview of methods to obtain human stem cell or blood monocyte-derived microglia-like cells that provide a nearly unlimited source of live human microglia for research. We address how understanding microglial ontogeny can help modeling microglial identity and function in a dish with increased accuracy. Moreover, we categorize stem cell-derived differentiation methods into embryoid body based, growth factor driven, and coculture-driven approaches, and review novel viral approaches to reprogram stem cells directly into microglia-like cells. Furthermore, we review typical readouts used in the field to verify microglial identity and characterize functional microglial phenotypes. We provide an overview of methods used to study microglia in environments more closely resembling the (developing) human CNS, such as cocultures and brain organoid systems with incorporated or innately developing microglia. We highlight how microglia-like cells can be utilized to reveal molecular and functional mechanisms in human disease context, focusing on Alzheimer's disease and other neurodegenerative diseases as well as neurodevelopmental diseases. Finally, we provide a critical overview of challenges and future opportunities to more accurately model human microglia in a dish and conclude that novel in vitro microglia-like cells provide an exciting potential to bring preclinical research of microglia to a new era.
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Diferenciação Celular , Microglia , Microglia/metabolismo , Humanos , Diferenciação Celular/fisiologia , Técnicas de Cocultura , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Técnicas de Cultura de CélulasRESUMO
Adaptations of the immune system throughout gestation have been proposed as important mechanisms regulating successful pregnancy. Dysregulation of the maternal immune system has been associated with adverse maternal and fetal outcomes. To translate findings from mechanistic preclinical studies to human pregnancies, studies of serum immune markers are the mainstay. The design and interpretation of human biomarker studies require additional insights in the trajectories and drivers of peripheral immune markers. The current study mapped maternal inflammatory markers (C-reactive protein (CRP), interleukin (IL)-1ß, IL-6, IL-17A, IL-23, interferon- γ ) during pregnancy and investigated the impact of demographic, environmental and genetic drivers on maternal inflammatory marker levels in four multi-ethnic and socio-economically diverse population-based cohorts with more than 12,000 pregnant participants. Additionally, pregnancy inflammatory markers were compared to pre-pregnancy levels. Cytokines showed a high correlation with each other, but not with CRP. Inflammatory marker levels showed high variability between individuals, yet high concordance within an individual over time during and pre-pregnancy. Pre-pregnancy body mass index (BMI) explained more than 9.6% of the variance in CRP, but less than 1% of the variance in cytokines. The polygenic score of CRP was the best predictor of variance in CRP (>14.1%). Gestational age and previously identified inflammation drivers, including tobacco use and parity, explained less than 1% of variance in both cytokines and CRP. Our findings corroborate differential underlying regulatory mechanisms of CRP and cytokines and are suggestive of an individual inflammatory marker baseline which is, in part, genetically driven. While prior research has mainly focused on immune marker changes throughout pregnancy, our study suggests that this field could benefit from a focus on intra-individual factors, including metabolic and genetic components.
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Prenatal infections and activation of the maternal immune system have been proposed to contribute to causing neurodevelopmental disorders (NDDs), chronic conditions often linked to brain abnormalities. Microglia are the resident immune cells of the brain and play a key role in neurodevelopment. Disruption of microglial functions can lead to brain abnormalities and increase the risk of developing NDDs. How the maternal as well as the fetal immune system affect human neurodevelopment and contribute to NDDs remains unclear. An important reason for this knowledge gap is the fact that the impact of exposure to prenatal risk factors has been challenging to study in the human context. Here, we characterized a model of cerebral organoids (CO) with integrated microglia (COiMg). These organoids express typical microglial markers and respond to inflammatory stimuli. The presence of microglia influences cerebral organoid development, including cell density and neural differentiation, and regulates the expression of several ciliated mesenchymal cell markers. Moreover, COiMg and organoids without microglia show similar but also distinct responses to inflammatory stimuli. Additionally, IFN-γ induced significant transcriptional and structural changes in the cerebral organoids, that appear to be regulated by the presence of microglia. Specifically, interferon-gamma (IFN-γ) was found to alter the expression of genes linked to autism. This model provides a valuable tool to study how inflammatory perturbations and microglial presence affect neurodevelopmental processes.
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Despite antiretroviral therapy (ART), HIV persistence in the central nervous system (CNS) continues to cause a range of cognitive impairments in people living with HIV (PLWH). Upon disease progression, transmigrating CCR5-using T-cell tropic viruses are hypothesized to evolve into macrophage-tropic viruses in the CNS that can efficiently infect low CD4-expressing cells, such as microglia. We examined HIV-1 RNA concentration, co-receptor usage, and CSF compartmentalization in paired CSF and blood samples from 19 adults not on treatment. Full-length envelope CSF- and plasma-derived reporter viruses were generated from 3 subjects and phenotypically characterized in human primary CD4+ T-cells and primary microglia. Median HIV RNA levels were higher in plasma than in CSF (5.01 vs. 4.12 log10 cp/mL; p = 0.004), and coreceptor usage was mostly concordant for CCR5 across the paired samples (n = 17). Genetically compartmentalized CSF viral populations were detected in 2 subjects, one with and one without neurological symptoms. All viral clones could replicate in T-cells (R5 T cell-tropic). In addition, 3 CSF and 1 plasma patient-derived viral clones also had the capacity to replicate in microglia/macrophages and, therefore have an intermediate macrophage tropic phenotype. Overall, with this study, we demonstrate that in a subset of PLWH, plasma-derived viruses undergo genetic and phenotypic evolution within the CNS, indicating viral infection and replication in CNS cells. It remains to be studied whether the intermediate macrophage-tropic phenotype observed in primary microglia represents a midpoint in the evolution towards a macrophage-tropic phenotype that can efficiently replicate in microglial cells and propagate viral infection in the CNS.
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Disturbances in T-cells, specifically the Th17/Treg balance, have been implicated in adverse pregnancy outcomes. We investigated these two T-cell populations following pre-pregnancy and pregnancy SARS-CoV-2 infection and COVID-19 vaccination in 351 participants from a pregnancy cohort in New York City (Generation C; 2020-2022). SARS-CoV-2 infection status was determined via laboratory or medical diagnosis and COVID-19 vaccination status via survey and electronic medical records data. Peripheral blood mononuclear cells (PBMCs) were collected at routine prenatal visits throughout gestation (median 108 days; IQR 67-191 days) with repeated measures for 104 participants (29.6%). T-cell populations CD4+/CD3+, Th17/CD4+, Treg/CD4+ and the Th17/Treg ratio were quantified using flow cytometry. Results showed that inter-individual differences are a main influencing factor in Th17 and Treg variance, however total variance explained remained small (R2 = 15-39%). Overall, Th17 and Treg populations were not significantly affected by SARS-CoV-2 infection during pregnancy in adjusted linear mixed models (p>0.05), however comparison of repeated measures among SARS-CoV-2 infected participants and non-infected controls suggests a relative increase of the Th17/Treg ratio following infection. In addition, the Th17/Treg ratio was significantly higher after SARS-CoV-2 infection prior to pregnancy (10-138 weeks) compared to controls (ß=0.48, p=0.003). COVID-19 vaccination was not associated with Th17 and Treg cells. Our findings suggest an impact of SARS-CoV-2 infection on the Th17/Treg ratio, likely depending on severity of infection, yet the observed trends and their potential consequences for pregnancy outcomes require further investigation. Our study contributes to growing evidence that COVID-19 vaccination during pregnancy does not lead to an exacerbated immune response.
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COVID-19 , Linfócitos T Reguladores , Gravidez , Feminino , Humanos , COVID-19/prevenção & controle , SARS-CoV-2 , Leucócitos Mononucleares , Vacinas contra COVID-19 , VacinaçãoRESUMO
Schizophrenia is one of the most debilitating mental disorders, and its diagnosis and treatment present significant challenges. Several clinical trials have previously evaluated the effectiveness of simvastatin, a lipid-lowering medication, as a novel add-on treatment for schizophrenia. However, treatment effects varied highly between patients and over time. In the present study, we aimed to identify biomarkers of response to simvastatin in recent-onset schizophrenia patients. To this end, we profiled relevant immune and metabolic markers in patient blood samples collected in a previous clinical trial (ClinicalTrials.gov: NCT01999309) before simvastatin add-on treatment was initiated. Analysed sample types included serum, plasma, resting-state peripheral blood mononuclear cells (PBMCs), as well as PBMC samples treated ex vivo with immune stimulants and simvastatin. Associations between the blood readouts and clinical endpoints were evaluated using multivariable linear regression. This revealed that changes in insulin receptor (IR) levels induced in B-cells by ex vivo simvastatin treatment inversely correlated with in vivo effects on cognition at the primary endpoint of 12 months, as measured using the Brief Assessment of Cognition in Schizophrenia scale total score (standardised ß ± SE = -0.75 ± 0.16, P = 2.2 × 10-4, Q = 0.029; n = 21 patients). This correlation was not observed in the placebo group (ß ± SE = 0.62 ± 0.39, P = 0.17, Q = 0.49; n = 14 patients). The candidate biomarker explained 53.4 % of the variation in cognitive outcomes after simvastatin supplementation. Despite the small sample size, these findings suggest a possible interaction between the insulin signalling pathway and cognitive effects during simvastatin therapy. They also point to opportunities for personalized schizophrenia treatment through patient stratification.
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Inibidores de Hidroximetilglutaril-CoA Redutases , Esquizofrenia , Humanos , Sinvastatina/uso terapêutico , Sinvastatina/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Leucócitos Mononucleares , Esquizofrenia/tratamento farmacológico , Esquizofrenia/induzido quimicamente , Biomarcadores , Suplementos Nutricionais , Método Duplo-CegoRESUMO
IMPORTANCE AND OBJECTIVE: The brain-penetrant tetracycline antibiotics, minocycline and doxycycline, have been proposed as potential candidate drugs for treatment of schizophrenia, based on preclinical studies and clinical trials. A potential long-term beneficial effect of these antibiotics for schizophrenia patients has not been investigated. This study was designed to determine if redemption of doxycycline prescription in schizophrenia is associated with decreased incidence of disability pension, a proxy for long-term functioning. DESIGN: We performed a population-based cohort study with data from schizophrenia patients available through the Danish registers. Survival analysis models with time-varying covariates were constructed to assess incidence rate ratios (IRR) of disability pension after exposure to doxycycline or a non-brain penetrant tetracycline, defined as at least one filled prescription. The analysis was adjusted for age, sex, calendar year, parental psychiatric status and educational level. RESULTS: We used data from 11,157 individuals with schizophrenia (4,945 female and 6,212 male; average age 22.4 years old, standard deviation (std) 4.50). 718 of these were exposed to brain-penetrant doxycycline, and 1,498 individuals redeemed a prescription of one or more of the non-brain-penetrant tetracyclines. The average years at risk per person in this cohort was 4.9, and 2,901 individuals received disability pension in the follow-up period. There was a significantly lower incidence rate of disability pension in schizophrenia patients who had redeemed doxycycline compared to patients who did not redeem a prescription of any tetracycline antibiotics (Incidence rate ratio (IRR) 0.68; 95 % CI 0.56, 0.83). There was also a significant lower rate of disability pension in schizophrenia patients who redeemed doxycycline compared to individuals who redeemed a prescription of one of the non-brain penetrant tetracycline antibiotics (IRR 0.69 95 % CI 0.55, 0.87). CONCLUSIONS: In this observational study, doxycycline exposure is associated with a reduced incidence of disability pension. These data support further studies on the potential long term neuroprotective effects of doxycycline and level of functioning in schizophrenia patients.
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Doxiciclina , Esquizofrenia , Feminino , Humanos , Masculino , Adulto Jovem , Antibacterianos/uso terapêutico , Estudos de Coortes , Doxiciclina/uso terapêutico , Minociclina , Esquizofrenia/tratamento farmacológico , TetraciclinaRESUMO
Cerebral organoids (CerOrgs) derived from human induced pluripotent stem cells (iPSCs) are a valuable tool to study human astrocytes and their interaction with neurons and microglia. The timeline of astrocyte development and maturation in this model is currently unknown and this limits the value and applicability of the model. Therefore, we generated CerOrgs from three healthy individuals and assessed astrocyte maturation after 5, 11, 19, and 37 weeks in culture. At these four time points, the astrocyte lineage was isolated based on the expression of integrin subunit alpha 6 (ITGA6). Based on the transcriptome of the isolated ITGA6-positive cells, astrocyte development started between 5 and 11 weeks in culture and astrocyte maturation commenced after 11 weeks in culture. After 19 weeks in culture, the ITGA6-positive astrocytes had the highest expression of human mature astrocyte genes, and the predicted functional properties were related to brain homeostasis. After 37 weeks in culture, a subpopulation of ITGA6-negative astrocytes appeared, highlighting the heterogeneity within the astrocytes. The morphology shifted from an elongated progenitor-like morphology to the typical bushy astrocyte morphology. Based on the morphological properties, predicted functional properties, and the similarities with the human mature astrocyte transcriptome, we concluded that ITGA6-positive astrocytes have developed optimally in 19-week-old CerOrgs.
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Células-Tronco Pluripotentes Induzidas , Transcriptoma , Humanos , Células Cultivadas , Astrócitos/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Perfilação da Expressão Gênica , Organoides , Diferenciação CelularRESUMO
Numerous studies reported an increase of postpartum mood symptoms during the COVID-19 pandemic. Yet, the link between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and perinatal mental health is less well understood. We investigated the associations between prenatal SARS-CoV-2 infection and postpartum depressive and anxiety symptoms, including examinations of infection timing and pandemic timeline. We included 595 participants from Generation C, a prospective pregnancy cohort in New York City (2020-2022). Prenatal SARS-CoV-2 infection was determined via laboratory or medical diagnosis. Depression and anxiety symptoms were measured 4-12 weeks postpartum using the Edinburgh Postnatal Depression Scale (EPDS) and Generalized Anxiety Disorder questionnaire (GAD), respectively. Quantile regressions were conducted with prenatal SARS-CoV-2 infection as exposure and continuously measured EPDS and GAD scores as outcomes. We reran the analyses in those with COVID-19-like symptoms in the trimester during which infection occurred. 120 (20.1%) participants had prenatal SARS-CoV-2 infection. After adjusting for socio-demographic, obstetric and other maternal health factors, prenatal SARS-CoV-2 infection was associated with higher median postpartum anxiety scores (b = 0.55, 95% CI = 0.15; 0.96). Late gestation infection (b = 1.15, 95% CI = 0.22; 2.09) and symptomatic infection (b = 1.15, 95% CI = 0.12; 2.18) were also associated with higher median postpartum anxiety scores. No associations were found with depressive symptoms. The associations were not moderated by time since the start of the pandemic. This study suggests that prenatal SARS-CoV-2 infection increases the risk of postpartum anxiety symptoms among participants reporting median anxiety symptoms. Given that this association was not affected by pandemic timing and that SARS-CoV-2 transmission continues, individuals infected with SARS-CoV-2 during pregnancy should be monitored for postpartum anxiety symptoms.
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COVID-19 , Depressão Pós-Parto , Feminino , Gravidez , Humanos , COVID-19/complicações , COVID-19/epidemiologia , Estudos Prospectivos , Cidade de Nova Iorque/epidemiologia , Pandemias , SARS-CoV-2 , Período Pós-Parto/psicologia , Ansiedade/psicologia , Depressão Pós-Parto/epidemiologia , Depressão Pós-Parto/psicologia , Depressão/psicologiaRESUMO
Microglia, the innate immune cells of the central nervous system, have been genetically implicated in multiple neurodegenerative diseases. We previously mapped the genetic regulation of gene expression and mRNA splicing in human microglia, identifying several loci where common genetic variants in microglia-specific regulatory elements explain disease risk loci identified by GWAS. However, identifying genetic effects on splicing has been challenging due to the use of short sequencing reads to identify causal isoforms. Here we present the isoform-centric microglia genomic atlas (isoMiGA) which leverages the power of long-read RNA-seq to identify 35,879 novel microglia isoforms. We show that the novel microglia isoforms are involved in stimulation response and brain region specificity. We then quantified the expression of both known and novel isoforms in a multi-ethnic meta-analysis of 555 human microglia short-read RNA-seq samples from 391 donors, the largest to date, and found associations with genetic risk loci in Alzheimer's disease and Parkinson's disease. We nominate several loci that may act through complex changes in isoform and splice site usage.
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There is convincing evidence from rodent studies suggesting that prenatal infections affect the offspring's brain, but evidence in humans is limited. Here, we assessed the occurrence of common infections during each trimester of pregnancy and examined associations with brain outcomes in adolescent offspring. Our study was embedded in the Generation R Study, a large-scale sociodemographically diverse prospective birth cohort. We included 1094 mother-child dyads and investigated brain morphology (structural MRI), white matter microstructure (DTI), and functional connectivity (functional MRI), as outcomes at the age of 14. We focused on both global and focal regions. To define prenatal infections, we composed a score based on the number and type of infections during each trimester of pregnancy. Models were adjusted for several confounders. We found that prenatal infection was negatively associated with cerebral white matter volume (B = -0.069, 95% CI -0.123 to -0.015, p = 0.011), and we found an association between higher prenatal infection scores and smaller volumes of several frontotemporal regions of the brain. After multiple testing correction, we only observed an association between prenatal infections and the caudal anterior cingulate volume (B = -0.104, 95% CI -0.164 to -0.045, p < 0.001). We did not observe effects of prenatal infection on other measures of adolescent brain morphology, white matter microstructure, or functional connectivity, which is reassuring. Our results show potential regions of interest in the brain for future studies; data on the effect of severe prenatal infections on the offspring's brain in humans are needed.
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Efeitos Tardios da Exposição Pré-Natal , Gravidez , Feminino , Adolescente , Humanos , Estudos Prospectivos , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Encéfalo/diagnóstico por imagem , Neuroimagem , Imageamento por Ressonância MagnéticaRESUMO
Microglia, the immune cells of the brain, are increasingly implicated in neurodegenerative disorders through genetic studies. However, how genetic risk factors for these diseases are related to microglial gene expression, microglial function, and ultimately disease, is still largely unknown. Microglia change rapidly in response to alterations in their cellular environment, which is regulated through changes in transcriptional programs, which are as yet poorly understood. Here, we compared the effects of a set of inflammatory and restorative stimuli (lipopolysaccharide, interferon-gamma, resiquimod, tumor necrosis factor-alpha, adenosine triphosphate, dexamethasone, and interleukin-4) on human microglial cells from 67 different donors (N = 398 samples) at the gene and transcript level. We show that microglia from different anatomical brain regions show distinct responses to inflammatory stimuli. We observed a greater overlap between human stimulated microglia and human monocytes than with mouse microglia. We define specific microglial signatures across conditions which are highly relevant for a wide range of biological functions and complex human diseases. Finally, we used our stimulation signatures to interpret associations from Alzheimer's disease (AD) genetic studies and microglia by integrating our inflammatory gene expression profiles with common genetic variants to map cis -expression QTLs (eQTLs). Together, we provide the most comprehensive transcriptomic database of the human microglia responsome. Highlights: RNA-sequencing of 398 human microglial samples exposed to six different triggers.Microglia from different anatomical regions show distinct stimulation responses.Responses in human microglia show a greater overlap with human monocytes than murine microglia.Mapping of response Quantitative Trait Loci identifies interactions between genotype and effect of stimulation on gene expression.Our atlas provides a reference map for interpreting microglia signatures in health and disease.
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OBJECTIVE: Obesity is one of the main concerns for public health and is becoming an increasingly widespread problem worldwide. Women are more likely to require a cesarean section and have a longer hospital stay after delivery. Excess body weight can interfere with ovulation and make it more difficult for embryos to implant in the uterus. A high body mass index (BMI) has controversial effects on the outcomes of medically assisted reproduction treatments (IVF) and, if careful counseling is not performed, medical-legal risks may be incurred. While some researchers argue that obesity does not particularly affect ART outcomes, other studies claim that a high BMI does not interfere with embryonic development. Both the American Society for Reproductive Medicine (ASRM) and the European Society of Human Reproduction and Embryology (ESHRE) has stated that there is no clear evidence supporting a BMI limit for IVF treatment and that each patient should be evaluated on an individual basis. The purpose of our study was to evaluate whether performing in vitro fertilization on these patients increases the risk of medical, surgical, and anesthetic complications of oocyte retrieval. PATIENTS AND METHODS: From January 2011 to December 2022, all patients with BMI higher than 25 were enrolled in the study (n=766). Complications and risks related to oocyte retrieval were evaluated, and patients were divided according to BMI groups. RESULTS: With the one-way ANOVA test, all groups were compared with the control group, and none showed statistically significant differences, only the number of produced embryos in the BMI group between 30-34.9 was lower and statistically significant. CONCLUSIONS: Only one study has analyzed these aspects, mainly focusing on the need for anesthesia drugs and any related complications, and the same author reported greater difficulty in performing oocyte retrieval. The same study recorded an increase in incomplete oocyte retrievals. Our work does not confirm any of these impressions.
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Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Recuperação de Oócitos , Humanos , Gravidez , Feminino , Recuperação de Oócitos/efeitos adversos , Técnicas de Reprodução Assistida/efeitos adversos , Cesárea , Obesidade/complicações , Fertilização in vitro/efeitos adversos , Taxa de Gravidez , Estudos RetrospectivosRESUMO
Immune-related mechanisms have been suggested to be involved in schizophrenia. Various studies have shown changes in monocytes isolated from the blood of schizophrenia patients, including changes in monocyte numbers, as well as altered protein and transcript levels of important markers. However, validation of these findings and understanding how these results are related to immune-related changes in the brain and schizophrenia genetic risk factors, is limited. The goal of this study was to better understand changes observed in monocytes of patients with early-onset schizophrenia. Using RNA sequencing, we analyzed gene expression profiles of monocytes isolated from twenty patients with early-onset schizophrenia and seventeen healthy controls. We validated expression changes of 7 out of 29 genes that were differentially expressed in previous studies including TNFAIP3, DUSP2, and IL6. At a transcriptome-wide level, we found 99 differentially expressed genes. Effect sizes of differentially expressed genes were moderately correlated with differential expression in brain tissue (Pearson's r = 0.49). Upregulated genes were enriched for genes in NF-κB and LPS signaling pathways. Downregulated genes were enriched for glucocorticoid response pathways. These pathways have been implicated in schizophrenia before and play a role in regulating the activation of myeloid cells. Interestingly, they are also involved in several non-inflammatory processes in the central nervous system, such as neurogenesis and neurotransmission. Future studies are needed to better understand how dysregulation of the NF-κB and glucocorticoid pathways affects inflammatory and non-inflammatory processes in schizophrenia. The fact that dysregulation of these pathways is also seen in brain tissue, provides potential possibilities for biomarker development.
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Monócitos , Esquizofrenia , Humanos , Monócitos/metabolismo , NF-kappa B/metabolismo , Esquizofrenia/genética , Esquizofrenia/metabolismo , Glucocorticoides/metabolismo , Perfilação da Expressão Gênica/métodosRESUMO
BACKGROUND: Doxycycline and minocycline are brain-penetrant tetracycline antibiotics, which recently gained interest because of their immunomodulatory and neuroprotective properties. Observational studies have suggested that exposure to these drugs may decrease the risk to develop schizophrenia, but results are inconsistent. The aim of this study was to investigate the potential association between doxycycline use and later onset of schizophrenia. DESIGN: We used data from 1 647 298 individuals born between 1980 and 2006 available through Danish population registers. 79 078 of those individuals were exposed to doxycycline, defined as redemption of at least 1 prescription. Survival analysis models stratified for sex with time-varying covariates were constructed to assess incidence rate ratios (IRRs) for schizophrenia (ICD-10 code F20.xx), with adjustment for age, calendar year, parental psychiatric status, and educational level. RESULTS: In the non-stratified analysis, there was no association between doxycycline exposure and schizophrenia risk. However, men who redeemed doxycycline had a significantly lower incidence rate for schizophrenia onset compared to men that did not (IRR 0.70; 95% CI 0.57-0.86). By contrast, women had a significantly higher incidence rate for schizophrenia onset, compared to women that did not redeem doxycycline prescriptions (IRR 1.23; 95% CI 1.08, 1.40). The effects were not found for other tetracycline antibiotics (IRR 1.00; 95% CI 0.91, 1.09). CONCLUSIONS: Doxycycline exposure is associated with a sex-dependent effect on schizophrenia risk. The next steps are replication of the results in independent well-characterized population cohorts, as well as preclinical studies to investigate sex-specific effects of doxycycline on biological mechanisms implicated in schizophrenia.
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Esquizofrenia , Masculino , Humanos , Feminino , Esquizofrenia/tratamento farmacológico , Esquizofrenia/epidemiologia , Esquizofrenia/complicações , Doxiciclina/efeitos adversos , Fatores de Risco , Minociclina , Antibacterianos/efeitos adversos , Sistema de Registros , Dinamarca/epidemiologiaRESUMO
There is a consensus in the field that microglia play a prominent role in neurodevelopmental processes like synaptic pruning and neuronal network maturation. Thus, a current momentum of associating microglia deficits with neurodevelopmental disorders (NDDs) emerged. This concept is challenged by rodent studies and clinical data. Intriguingly, reduced numbers of microglia or altered microglial functions do not necessarily lead to overt NDD phenotypes, and neuropsychiatric symptoms seem to develop primarily in adulthood. Hence, it remains open for discussion whether microglia are truly indispensable for healthy neurodevelopment. Here, we critically discuss the role of microglia in synaptic pruning and highlight area- and age dependency. We propose an updated model of microglia-mediated synaptic pruning in the context of NDDs and discuss the potential of targeting microglia for treatment of these disorders.
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Microglia , Transtornos do Neurodesenvolvimento , Humanos , Microglia/fisiologia , Neurogênese , Plasticidade Neuronal/fisiologia , Sinapses/fisiologiaRESUMO
Various lines of research suggest immune dysregulation as a potential therapeutic target for negative and cognitive symptoms in schizophrenia spectrum disorders (SSD). Immune dysregulation would lead to higher extracellular free-water (EFW) in cerebral white matter (WM), which may partially underlie the frequently reported lower fractional anisotropy (FA) in SSD. We aim to investigate differences in EFW concentrations - a presumed proxy for neuro-inflammation - between early-phase SSD patients (n = 55) and healthy controls (HC; n = 37), and to explore immunological and cognitive correlates. To increase specificity for EFW, we study several complementary magnetic resonance imaging contrasts that are sensitive to EFW. FA, mean diffusivity (MD), magnetization transfer ratio (MTR), myelin water fraction (MWF) and quantitative T1 and T2 were calculated from diffusion-weighted imaging (DWI), magnetization transfer imaging (MTI) and multicomponent driven equilibrium single-pulse observation of T1/T2 (mcDESPOT). For each measure, WM skeletons were constructed with tract-based spatial statistics. Multivariate SSD-HC comparisons with WM skeletons and their average values (i.e. global WM) were not statistically significant. In voxel-wise analyses, FA was significantly lower in SSD in the genu of the corpus callosum and in the left superior longitudinal fasciculus (p < 0.04). Global WM measures did not correlate with immunological markers (i.e. IL1-RA, IL-6, IL-8, IL-10 and CRP) or cognition in HC and SSD after corrections for multiple comparisons. We confirmed lower FA in early-phase SSD patients. However, nonFA measures did not provide additional evidence for immune dysregulation or for higher EFW as the primary mechanism underlying the reported lower FA values in SSD.
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Immune dysregulation has been reported in schizophrenia spectrum disorders (SSD). In the past decade, several trials using anti-inflammatory agents for treatment of SSD have been completed, with so far limited success. One such anti-inflammatory agent used is simvastatin. A recent, large-scale, randomized controlled trial with simvastatin augmentation failed to show improvement in the predefined primary outcome. However, baseline inflammatory profiles were not taken into account. Here we employed a data-driven clustering approach to investigate whether patients with an inflammatory monocyte gene signature respond better to add-on simvastatin treatment than those without such a signature, over a treatment period of 2 years. In 61 patients (60 randomized, 1:1 placebo:simvastatin) and healthy controls, a previously validated monocyte gene expression signature was assessed using quantitative polymerase chain reaction. Resulting delta cycle threshold values were used to identify patient clusters. Two major patient clusters with either up- or downregulated pro-inflammatory factors were detected. Linear mixed models showed a significant three-way interaction between the inflammatory cluster, treatment, and time for psychotic symptoms. Only patients treated with simvastatin who were in the inflammatory group, showed a consistent improvement: symptom severity gradually decreased after 3 months and reached significance after 12 and 24 months compared to baseline (p.adj<0.05). The effects were small, and overall between-group effects were not significant. Here, we show that patient stratification based on inflammatory gene expression might be useful to select appropriate treatment augmentation for patients with SSD, highlighting the need for precision medicine approaches. Our findings corroborate the results of the primary analyses, showing that in the overall group, simvastatin was not effective; however, at the individual level the treatment might make a difference.
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A significant proportion of the personal and economic burden of schizophrenia can be attributed to the late diagnosis or misdiagnosis of the disorder. A novel, objective diagnostic approaches could facilitate the early detection and treatment of schizophrenia and improve patient outcomes. In the present study, we aimed to identify robust schizophrenia-specific blood biomarkers, with the goal of developing an accurate diagnostic model. The levels of selected serum and peripheral blood mononuclear cell (PBMC) markers relevant to metabolic and immune function were measured in healthy controls (n = 26) and recent-onset schizophrenia patients (n = 36) using multiplexed immunoassays and flow cytometry. Analysis of covariance revealed significant upregulation of insulin receptor (IR) and fatty acid translocase (CD36) levels in T helper cells (F = 10.75, P = 0.002, Q = 0.024 and F = 21.58, P = 2.8 × 10-5, Q = 0.0004, respectively), as well as downregulation of glucose transporter 1 (GLUT1) expression in monocytes (F = 21.46, P = 2.9 × 10-5, Q = 0.0004). The most robust predictors, monocyte GLUT1 and T helper cell CD36, were used to develop a diagnostic model, which showed a leave-one-out cross-validated area under the receiver operating characteristic curve (AUC) of 0.78 (95% CI: 0.66-0.92). The diagnostic model was validated in two independent datasets. The model was able to distinguish first-onset, drug-naïve schizophrenia patients (n = 34) from healthy controls (n = 39) with an AUC of 0.75 (95% CI: 0.64-0.86), and also differentiated schizophrenia patients (n = 22) from patients with other neuropsychiatric conditions, including bipolar disorder, major depressive disorder and autism spectrum disorder (n = 68), with an AUC of 0.83 (95% CI: 0.75-0.92). These findings indicate that PBMC-derived biomarkers have the potential to support an accurate and objective differential diagnosis of schizophrenia.
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Transtorno do Espectro Autista , Transtorno Depressivo Maior , Esquizofrenia , Humanos , Esquizofrenia/metabolismo , Leucócitos Mononucleares/metabolismo , Transtorno Depressivo Maior/metabolismo , Transtorno do Espectro Autista/metabolismo , Transportador de Glucose Tipo 1/metabolismo , BiomarcadoresRESUMO
The most studied HIV eradication approach is the "shock and kill" strategy, which aims to reactivate the latent reservoir by latency reversing agents (LRAs) and allowing elimination of these cells by immune-mediated clearance or viral cytopathic effects. The CNS is an anatomic compartment in which (persistent) HIV plays an important role in HIV-associated neurocognitive disorder. Restriction of the CNS by the blood-brain barrier is important for maintenance of homeostasis of the CNS microenvironment, which includes CNS-specific cell types, expression of transcription factors, and altered immune surveillance. Within the CNS predominantly myeloid cells such as microglia and perivascular macrophages are thought to be a reservoir of persistent HIV infection. Nevertheless, infection of T cells and astrocytes might also impact HIV infection in the CNS. Genetic adaptation to this microenvironment results in genetically distinct, compartmentalized viral populations with differences in transcription profiles. Because of these differences in transcription profiles, LRAs might have different effects within the CNS as compared with the periphery. Moreover, reactivation of HIV in the brain and elimination of cells within the CNS might be complex and could have detrimental consequences. Finally, independent of activity on latent HIV, LRAs themselves can have adverse neurologic effects. We provide an extensive overview of the current knowledge on compartmentalized (persistent) HIV infection in the CNS and on the "shock and kill" strategy. Subsequently, we reflect on the impact and promise of the "shock and kill" strategy on the elimination of persistent HIV in the CNS.