Browsing by Author "Canedo, Teresa"
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- Astrocyte-derived TNF and glutamate critically modulate microglia activation by methamphetaminePublication . Canedo, Teresa; Portugal, Camila Cabral; Socodato, Renato; Almeida, Tiago Oliveira; Terceiro, Ana Filipa; Bravo, Joana; Silva, Ana Isabel; Magalhães, João Duarte; Guerra-Gomes, Sónia; Oliveira, João Filipe; Sousa, Nuno; Magalhães, Ana; Relvas, João Bettencourt; Summavielle, TeresaMethamphetamine (Meth) is a powerful illicit psychostimulant, widely used for recreational purposes. Besides disrupting the monoaminergic system and promoting oxidative brain damage, Meth also causes neuroinflammation, contributing to synaptic dysfunction and behavioral deficits. Aberrant activation of microglia, the largest myeloid cell population in the brain, is a common feature in neurological disorders triggered by neuroinflammation. In this study, we investigated the mechanisms underlying the aberrant activation of microglia elicited by Meth in the adult mouse brain. We found that binge Meth exposure caused microgliosis and disrupted risk assessment behavior (a feature that usually occurs in individuals who abuse Meth), both of which required astrocyte-to-microglia crosstalk. Mechanistically, Meth triggered a detrimental increase of glutamate exocytosis from astrocytes (in a process dependent on TNF production and calcium mobilization), promoting microglial expansion and reactivity. Ablating TNF production, or suppressing astrocytic calcium mobilization, prevented Meth-elicited microglia reactivity and re-established risk assessment behavior as tested by elevated plus maze (EPM). Overall, our data indicate that glial crosstalk is critical to relay alterations caused by acute Meth exposure.
- Deciphering neuroimmune interactions in alcohol intake in mouse model of intermittent access in male and femalePublication . Pacheco, Raquel; Canedo, Teresa; Rodrigues, Ana M.; Moreira, Joana; Relvas, João B.; Socodato, Renato; Summavielle, Teresa; Summavielle, TeresaExcessive alcohol consumption continues to pose a significant global health challenge, with detrimental effects on millions of individuals. Our laboratory has shown that alcohol exposure triggers reactive changes in astrocytes, including alterations in gene expression, activity, and proliferation, while also affecting microglial morphology and immune responses. We are to characterizing the effects of chronic alcohol consumption using a wellestablished voluntary alcohol drinking model in adult mice, to investigate the impact of chronic alcohol exposure on the prefrontal cortex (PFC), focusing on glial cell morphology, synaptic density, and behaviour. Mice are exposed to intermittent “every-other-day” (EOD) access to alcohol 15% (v/v) for 3 weeks, and behaviourally tested for anxiety, depression and memory, before sacrifice at 21 days of alcohol, or at 7 days of withdrawal. Brains were processed for glial cell analysis. Our preliminary findings revealed sex-specific responses following chronic alcohol exposure. Male mice exhibited increased astrocyte volume in the ventromedial PFC (vmPFC) and hyper-ramification in the ventrolateral PFC (vlPFC), whereas females displayed reductions in astrocyte size and complexity. Microglia morphology also differed between sexes, with females showing increased cell volume and males displaying reduced microglial volume in the vlPFC. These results suggest distinctive immune and synaptic responses to ethanol in males and females. Of note, we observed heightened inhibitory synapse density in the male PFC, while females exhibited increased excitatory synapse density. We are now conducting a proteomic analysis of PFC synaptosomes to identify important molecular targets in the crosstalk between neuros and glial cells. With this work we expect to clarify the complex interplay between chronic ethanol exposure, sex, and PFC function, find also new targets for innovative therapeutic approaches.
- Deciphering the astrocytic and synaptic changes under chronic alcohol exposure using a self-administration paradigmPublication . Rodrigues, Ana Margarida; Canedo, Teresa; Terceiro, Ana Filipa; Tedim-Moreira, Joana; Silva, Ana Isabel; Magalhães, Ana; Relvas, João; Summavielle, TeresaDrug abuse is characterized by a compulsive and persistent drug-seeking behaviour, despite the harmful emotional, physical and social consequences. Our laboratory has previously found that the neuronal-glial crosstalk is critical in relaying the changes caused by acute exposure to psychoactive drugs through neuroimmune mechanisms. We have also reported that microglia can engulf postsynaptic components in the prefrontal cortex (PFC) of mice after repeated alcohol exposure and this led to increased anxiety in mice. The adverse effects of alcohol on the central nervous system (CNS) are well described, with astrocytes becoming reactive and displaying changes in gene expression, activity and proliferation. However, the mechanisms involved are not yet fully understood. We are currently characterizing the astrocytic response under chronic alcohol consumption, taking into account the crucial interaction between neuronal and glial cells in the development and maintenance of addiction. Using a well-established voluntary alcohol drinking paradigm, we are evaluating alcohol-associated changes in PFC astrocytes, synapses and their behavioural correlates. Our preliminary results indicate similar alcohol consumption patterns between males and females, however, males, but not females, present altered weight gain and experience a significant increase in inhibitory synapse density after chronic exposure to ethanol when compared to the control group. Our work is contributing to a better understanding of the impact of chronic alcohol intake and may lead to the development of new strategies for pharmacological intervention in drug addiction, based on the targets identified as critical for the neuronal-glial crosstalk.
- IL-10 and Cdc42 modulate astrocyte-mediated microglia activation in methamphetamine-induced neuroinflammationPublication . Silva, Ana Isabel; Socodato, Renato; Pinto, Carolina; Terceiro, Ana Filipa; Canedo, Teresa; Relvas, João Bettencourt; Saraiva, Margarida; Summavielle, TeresaMethamphetamine (Meth) use is known to induce complex neuroinflammatory responses, particularly involving astrocytes and microglia. Building upon our previous research, which demonstrated that Meth stimulates astrocytes to release tumor necrosis factor (TNF) and glutamate, leading to microglial activation, this study investigates the role of the anti-inflammatory cytokine interleukin-10 (IL-10) in this process. Our findings reveal that the presence of recombinant IL-10 (rIL-10) counteracts Meth-induced excessive glutamate release in astrocyte cultures, which significantly reduces microglial activation. This reduction is associated with the modulation of astrocytic intracellular calcium (Ca2+) dynamics, particularly by restricting the release of Ca2+ from the endoplasmic reticulum to the cytoplasm. Furthermore, we identify the small Rho GTPase Cdc42 as a crucial intermediary in the astrocyte-to-microglia communication pathway under Meth exposure. By employing a transgenic mouse model that overexpresses IL-10 (pMT-10), we also demonstrate in vivo that IL-10 prevents Meth-induced neuroinflammation. These findings not only enhance our understanding of Meth-related neuroinflammatory mechanisms, but also suggest IL-10 and Cdc42 as putative therapeutic targets for treating Meth-induced neuroinflammation.
- Microglia dysfunction caused by the loss of rhoa disrupts neuronal physiology and leads to neurodegenerationPublication . Socodato, Renato; Portugal, Camila C.; Canedo, Teresa; Rodrigues, Artur; Almeida, Tiago O.; Henriques, Joana F.; Vaz, Sandra H.; Magalhães, João; Silva, Cátia M.; Baptista, Filipa I.; Alves, Renata L.; Coelho-Santos, Vanessa; Silva, Ana Paula; Paes-de-Carvalho, Roberto; Magalhães, Ana; Brakebusch, Cord; Sebastião, Ana M.; Summavielle, Teresa; Ambrósio, António F.; Relvas, João B.Nervous tissue homeostasis requires the regulation of microglia activity. Using conditional gene targeting in mice, we demonstrate that genetic ablation of the small GTPase Rhoa in adult microglia is sufficient to trigger spontaneous microglia activation, producing a neurological phenotype (including synapse and neuron loss, impairment of long-term potentiation [LTP], formation of β-amyloid plaques, and memory deficits). Mechanistically, loss of Rhoa in microglia triggers Src activation and Src-mediated tumor necrosis factor (TNF) production, leading to excitotoxic glutamate secretion. Inhibiting Src in microglia Rhoa-deficient mice attenuates microglia dysregulation and the ensuing neurological phenotype. We also find that the Rhoa/Src signaling pathway is disrupted in microglia of the APP/PS1 mouse model of Alzheimer disease and that low doses of Aβ oligomers trigger microglia neurotoxic polarization through the disruption of Rhoa-to-Src signaling. Overall, our results indicate that disturbing Rho GTPase signaling in microglia can directly cause neurodegeneration.
- Microglial Rac1 is essential for experience-dependent brain plasticity and cognitive performancePublication . Socodato, Renato; Almeida, Tiago O.; Portugal, Camila C.; Santos, Evelyn C.S.; Tedim-Moreira, Joana; Ferreira, João Galvão; Canedo, Teresa; Baptista, Filipa I.; Magalhães, Ana; Ambrósio, António F.; Brakebusch, Cord; Rubinstein, Boris; Moreira, Irina S.; Summavielle, Teresa; Pinto, Inês Mendes; Relvas, João B.Microglia, the largest population of brain immune cells, continuously interact with synapses to maintain brain homeostasis. In this study, we use conditional cell-specific gene targeting in mice with multi-omics approaches and demonstrate that the RhoGTPase Rac1 is an essential requirement for microglia to sense and interpret the brain microenvironment. This is crucial for microglia-synapse crosstalk that drives experience-dependent plasticity, a fundamental brain property impaired in several neuropsychiatric disorders. Phosphoproteomics profiling detects a large modulation of RhoGTPase signaling, predominantly of Rac1, in microglia of mice exposed to an environmental enrichment protocol known to induce experience-dependent brain plasticity and cognitive performance. Ablation of microglial Rac1 affects pathways involved in microglia-synapse communication, disrupts experience-dependent synaptic remodeling, and blocks the gains in learning, memory, and sociability induced by environmental enrichment. Our results reveal microglial Rac1 as a central regulator of pathways involved in the microglia-synapse crosstalk required for experience-dependent synaptic plasticity and cognitive performance.
- Neuron–microglia contact-dependent mechanisms attenuate methamphetamine-induced microglia reactivity and enhance neuronal plasticityPublication . Bravo, Joana; Ribeiro, Inês; Terceiro, Ana Filipa; Andrade, Elva B.; Portugal, Camila Cabral; Lopes, Igor M.; Azevedo, Maria M.; Sousa, Mafalda; Lopes, Cátia D. F.; Lobo, Andrea C.; Canedo, Teresa; Relvas, João Bettencourt; Summavielle, TeresaExposure to methamphetamine (Meth) has been classically associated with damage to neuronal terminals. However, it is now becoming clear that addiction may also result from the interplay between glial cells and neurons. Recently, we demonstrated that binge Meth administration promotes microgliosis and microglia pro-inflammation via astrocytic glutamate release in a TNF/IP3R2-Ca2+-dependent manner. Here, we investigated the contribution of neuronal cells to this process. As the crosstalk between microglia and neurons may occur by contact-dependent and/or contact-independent mechanisms, we developed co-cultures of primary neurons and microglia in microfluidic devices to investigate how their interaction affects Meth-induced microglia activation. Our results show that neurons exposed to Meth do not activate microglia in a cell-autonomous way but require astrocyte mediation. Importantly, we found that neurons can partially prevent Meth-induced microglia activation via astrocytes, which seems to be achieved by increasing arginase 1 expression and strengthening the CD200/CD200r pathway. We also observed an increase in synaptic individual area, as determined by co-localization of pre- and post-synaptic markers. The present study provides evidence that contact-dependent mechanisms between neurons and microglia can attenuate pro-inflammatory events such as Meth-induced microglia activation.
- Regulation of CD47 expression by interferon-gamma under chronic Methamphetamine exposure TitlePublication . Rodrigues, João; Bravo, Joana; Bonifácio Andrade, Elva; Canedo, Teresa; Azevedo, Maria; Summavielle, TeresaExposure to methamphetamine (Meth), a highly addictive widely used psychostimulant, is classically associated with damage to neuronal terminals, but its neurotoxicity can also be mediated via activation of the neuroinflammatory response. Microglia, the resident immune cells of the brain, become highly activated and increase the release of proinflammatory mediators upon exposure to Meth. However, their role in Meth-associated neurotoxicity is still not sufficiently understood. Data from our lab shows that, in the hippocampus, chronic Meth administration leads to microglia homeostasis dysregulation, synapse dysregulation, and downregulation of cluster-differentiation 47 protein (CD47). The crosstalk between CD47 and its receptor, signal regulatory protein α (SIRPα), is an important “don’t eat me signal” that inhibits phagocytosis. CD47 has been shown to protect synapses from excessive microglia-mediated pruning during development and neurodegeneration. Of note, in cancer cells CD47 expression is modulated by interferon-gamma (IFN-γ). Consistently, after chronic Meth, we observed a significant decrease of meningeal T cells, and a decrease in the production of IFN-y by these cells. Here we aim to clarify if IFNγ is regulating CD47 in the brain after chronic Meth administration, and consequently regulating synaptic pruning, using IFNyKO mice and wild-type mice injected with recombinant IFNy via stereotaxic surgery. Preliminary results indicate that IFNy/CD47 does not modulate microglia morphology and number after chronic Meth in the hippocampus. Currently we are evaluating synapses and phagocytosis, and we further expect to clarify the impact of IFNγ /CD47 in the chronic Meth conditioning and in memory.