Astrocytes

Cagla Eroglu presents research on how astrocytes regulate synaptic connectivity during development, function and plasticity. The seminar examines molecular and cellular mechanisms that shape neural circuits using imaging, mouse models and complementary experimental approaches.

…functional studies address microglia, astrocytes and myelinating cells, including diversity within each class and their contributions to circuits, behaviour and neurodegeneration. Programme themes cover neurodevelopmental and psychiatric disorders, ageing, human glia, glia-focused technologies, and interactions with immune cells and other glia. Talks, posters and extended discussion support exchange among established researchers and trainees. Applicants n

This EMBO Workshop brings together researchers studying astrocytes from molecular mechanisms to systems-level brain functions. The programme covers astrocyte roles in synapse assembly, circuit modulation, homeostasis, metabolism, memory, behavior, the blood-brain barrier, interactions with neurons and glia, and emerging therapeutic strategies.

Astrocytes help sustain neural signaling and tissue stability, but injury and implanted devices cause them to change their functions. Tim O'Shea examines how the extent and timing of this response determine tissue protection, regeneration and implant durability. Limited renewal of adult astrocytes contrasts with the greater proliferation and migration of immature cells in newborn mammals. Around implants, continuing movement, infection and other stimuli can prolong the response and affect device performance. The talk uses astrocyte-specific transcriptomic assays to investigate this reprogrammi

…how aging can alter microglia and astrocytes, affecting the immune and metabolic support that neurons receive. The conversation explores research on inflammatory signaling and the possibility that immune dysfunction outside the brain contributes to neurodegeneration. It also examines experiments in which targeting peripheral inflammation restored memory in mouse models, and why human clinical studies are needed to establish whether these fi

…Astrocytes and neurons, for instance, diverge dramatically in their reliance on glycolysis versus oxidative phosphorylation, underscoring that metabolic fuel efficiency is not uniform across cell types. A key factor shaping this divergence is the structural organization of the mitochondrial respiratory chain into supercomplexes. Specifically, complexes I (CI) and III (CIII) form a CI–CIII supercomplex, but the degree of this assembly varies by cell type. In neurons, CI is predominant

Astrocytes release glutamate by regulated exocytosis in health and disease Vladimir Parpura, International Translational Neuroscience Research Institute, Zhejiang Chinese Medical University, Hangzhou, P.R. China Parpura will present you with the evidence that astrocytes, a subtype of glial cells in the brain, can exocytotically release the neurotransmitter glutamate and how this release is regulated. Spatiotemporal characteristic of vesicular fusion that underlie glutamate release in astrocytes will be discussed. He will also present data on a translational project in which this release pathwa

A growing number of studies indicate the possible involvement of astrocytes in triggering or modulating neurovascular coupling (NVC), i.e. the local dilation of blood vessels in the brain in response to neuronal activity [1]. Their endfeet, surrounding arterioles and capillaries, are ideally positioned to deliver vasodilators to mural cells, either vascular smooth muscle cells or pericytes. Additionnaly, recent EM data suggest contact between endfeet and synapses [2], indicating direct interactions. At the interface between synapses and vessels, endfeet are perfect candidates to mediate NVC. R

…Glial cells, including astrocytes and microglia, have been found to influence various aspects of neuronal function, such as regulating neurotransmitter concentrations and ion buffering. Yet, the mechanisms through which glial cells communicate with and affect neighboring neurons remain unclear. In this study, we seek to develop a computational model to explore recent experimental findings which demonstrated that glial cells physically wrap around, o

Dense Associative Memories (Dense AMs) are energy-based neural networks that share many desirable features of celebrated Hopfield Networks but have superior information storage capabilities. In contrast to conventional Hopfield Networks, which were popular in the 1980s, DenseAMs have a very large memory storage capacity - possibly exponential in the size of the network. This aspect makes them appealing tools for many problems in AI and neurobiology. In this talk I will describe two theories of how DenseAMs might be built in biological “hardware”. According to the first theory, DenseAMs arise a

Astrocytes play a crucial role in regulating synaptic strength and orchestrating synaptic plasticity, which is fundamental for learning and memory. However, the specific mechanisms by which astrocytes and their neuroactive transmitters, like D-serine, control these processes remain largely unexplored. D-serine, a co-agonist for the NMDA receptor, has garnered increasing interest as a potential regulatory molecule in synaptic plasticity. Given its activity-dependent release mediated by astrocytes, D-serine is a key player in balancing long-term synaptic depression (LTD) and potentiation (LTP) d

…cAMP signaling is not well studied in astrocytes so far. Flamindo2 from Odaka et al. (PLOS One 9:6, 2014) is a genetically encoded cAMP sensor, which fluorescence intensity decreases in response to increased cAMP levels. In this study we investigated noradrenergic cAMP signaling in astrocytes

Calcium ions (Ca2+) play pivotal roles in regulating diverse brain functions, including cognition, emotion, locomotion, and learning and memory. These functions are intricately regulated by a variety of Ca2+-dependent cellular processes, encompassing synaptic plasticity, neuro/gliotransmitter release, and gene expression. In our previous work, we developed 'monster OptoSTIM1' (monSTIM1), an improved OptoSTIM1 that selectively activates Ca2+-release-activated Ca2+ (CRAC) channels in the plasma membrane through blue light, allowing precise control over intracellular Ca2+ signaling and specific b

During development, critical periods of synaptic plasticity facilitate the reordering and refinement of neural connections, allowing the definitive synaptic circuits responsible for correct adult physiology to be established. The L4-L2/3 synapses in the somatosensory cortex (S1) exhibit a presynaptic form of spike timing-dependent long-term depression (t-LTD) that probably fulfills a role in synaptic refinement. This t-LTD persists until the 4rd postnatal week in mice, disappearing thereafter. When we investigated the mechanisms underlying this maturation-related loss of t-LTD in mouse slices,

Molecular signals mediating systemic inflammation entering the brain parenchyma to induce sepsis-associated encephalopathy (SAE) remain elusive. In this study, we demonstrate that peripheral lipopolysaccharide (LPS)-induced systemic inflammation could rapidly increase the plasma adenosine concentration, peaking at 6 hours post LPS injection (hpi). Using in vivo 2P-LSM imaging of adenosine sensor GRABAdo, we observed elevated adenosine levels in the cortex of awake mice, also peaking at 6 hpi. These concomitant pathological events strongly suggest adenosine in the circulation can join forces to

…Here, we analyzed astrocytes and neurons in the neocortical access tissue of younger (22 - 50 years) and older (51 - 72 years) human who underwent resection of glioma or other cancer metastases to the brain. Aging decreased the amount of reduced mitochondrial cytochromes in astrocytes but not neurons. The protein-to-lipid ratio was decreased in astrocytes and increased in neurons. Aged astrocytes showed morphological dystrophy quantified by the decreased length of branches, decreased volume fraction of leaflets, and shri

The neurovascular unit (NVU) represents the structural and functional relationship between the neural tissue and the blood. Neurovascular dysfunction has been highlighted in neuropsychiatric afflictions, but it is still unclear whether it is a cause or a consequence of the pathology. Studying how NVU components associate might clarify its role on the emergence of emotional-cognitive dysfunction. This study aims at investigating whether the development of depressive-related loss of motivation is grounded on NVU modifications impacting the permeability of the blood-brain barrier (BBB) and in par

Astrocytes display complex morphology ranging from multiple main processes stemming from the soma to endfeet and a myriad of leaflets that are in close contact with synapses and other cellular structures. This extended feature, which is heterogeneous across brain regions and physiological states, is pivotal to understanding their dynamic interactions with neighboring neurons and glia. Therefore, assessing astrocytic structures is crucial to understanding their roles in brain networks. Immunostaining for Glial Fibrillary Acidic Protein (GFAP), an astrocyte-specific cytoskeletal protein, is comm

…Using calcium imaging of neurons and astrocytes in the APP/PS1 double transgenic Alzheimer’s disease mouse model, we investigated behavioural and cellular responses to repetitive visual stimuli, in comparison with littermate wild type (WT) mice.We collected data from 32 female

…of the identity and the roles of astrocytes and their involvement in cognitive abilities. Indeed, they play a crucial role in brain functions, they show primate-specific features, and they are relevant in several diseases. Investigations on astrocytes across evolution have rarely been performed. However, a comprehensive comparison of astrocytes in a diverse range of mammals is pivotal for understanding the morphology across species and the related modifications in gene expression and functions. Our project aims to

Astrocytes interact with neurons at a cellular and molecular level, modulating the synaptic formation, maturation, and function. Their unique morphology allows them to contact synaptic structures to sense, process, and respond to incoming signals. Astrocyte activation leads to intracellular calcium-dependent processes that ultimately modulate circuit function and animal behavior. The IP3 receptor type 2 knockout (IP3R2 KO) mouse model lacks calcium elevations upon astrocytic activation and, therefore, is a good model for studying the roles of intracellular calcium signaling in circuit function

…to be detected by both neurons and astrocytes. Noradrenergic α-1 receptors are Gq-coupled receptors that induce intracellular calcium release from the endoplasmic reticulum as a key pathway for astrocyte calcium signalling. Due to interactions between astrocytes and synapses including their known roles in structural isolation of synapses, metabolic support, potassium buffering and gliotransmitter release, fluctuations of intracellular calcium in astrocytes can influe

…Our aim was to determine the role of astrocytes in these processes, using in vivo whisker deprivation and ex vivo fEPSP recordings. In response to a week of unilateral all-whisker sensory deprivation of one side of the snout, a PKA-dependent form of long term potentiation (LTP) emerges at L4-L2/3 synapses in the contralateral barrel cortex, in addition to the NMDA receptor de

Astrocytes communicate bidirectionally with neurons by forming close contacts to synapses called tripartite synapses. Hundreds of thousands of synapses are embedded in a territory of single astrocytes, however, how astrocytes are functionally built into the neuronal circuits remains undetermined. To address this, we adopted the rabies virus (RV) for retrograde tracing of neuron-to-astrocyte connections in the mouse cerebral cortex. To sparsely and specifically transduce astrocytes with RV, a transposon vector expressing TVA, RV glycoprotein, and tdTomato under an astrocyte-specific promoter Gf