Polarized microtubule remodeling transforms the morphology of reactive microglia cells and drives cytokine release
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE238210 | GEO | 2023/09/21
REPOSITORIES: GEO
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Project description:Microglial activation is a pathological hallmark in many neurodegenerative diseases. During activation, microglia undergo complex morphological changes, including loss of their characteristic ramified cell morphology, which is routinely used to detect and quantify inflammation in the brain. However, the molecular mechanisms enabling this morphological change and the relation between microglial cell morphology and its pathophysiological function are not understood. Here, proteomic profiling of activated microglia identified microtubule remodeling pathways as an early factor that drives the morphological change and subsequently controls cytokine responses. We found that activated microglia increase their microtubule dynamics to form a stable and centrosomally anchored microtubule array to facilitate efficient cytokine trafficking and release. Moreover, we identified cyclin-dependent kinase 1 (Cdk-1) as a critical upstream regulator of microtubule remodeling and morphological change in vitro and in vivo. These results demonstrate a critical role for microtubule dynamics and reorganization in microglial activation and modulating cytokine-mediated inflammatory responses.
| MSV000090254 | MassIVE
Project description:Microglia colonize the brain parenchyma at early stages of development and accumulate in specific regions where they actively participate in cell death, angiogenesis, neurogenesis and synapse elimination. A recurring feature of embryonic microglial distribution is their association with developing axon tracts which, together with in vitro data, supports the idea of a physiological role for microglia in neurite development. Yet the demonstration of this role of microglia is still lacking. Here, we have studied the consequences of microglial dysfunction on the formation of the corpus callosum, the largest connective structure in the mammalian brain, which shows consistent microglial accumulation during development. We studied two models of microglial dysfunction: the loss-of-function of DAP12, a key microglial-specific signaling molecule, and a model of maternal inflammation by peritoneal injection of LPS at E15.5. We performed transcriptional profiling of maternally inflamed and Dap12-mutant microglia at E17.5. We found that both treatments principally down-regulated genes involved in nervous system development and function, particularly in neurite formation. We then analyzed the functional consequences of these microglial dysfunctions on the formation of the corpus callosum. We also took advantage of the Pu.1-/- mouse line, which is devoid of microglia. We now show that all three models of altered microglial activity resulted in the same defasciculation phenotype. Our study demonstrates that microglia are actively involved in the fasciculation of corpus callosum axons. To investigate possible roles for microglial during brain development, we challenged microglial function by two complementary approaches. First, we induced maternal inflammation by peritoneal injection of LPS into pregnant dams. Next, we analyzed the consequences of a loss of function of DAP12, a signaling molecule specifically expressed in microglia that is crucial for several aspects of microglia biology (references in Wakselman et al., 2008). We compared the gene expression profiles of microglia from control, maternally-inflamed by LPS (MI), and Dap12-mutated embryos. We isolated RNA from FACS sorted maternally inflamed (by LPS) and Dap12-mutant microglia at E17.5 pooled per pregnant dam; as a control we included PBS treated and untreated (UT) microglia. We compared gene expression between maternally inflamed microlgia (PBSvsLPS) and DAP12-mutant microglia (UTvsDAP12KO).
2014-07-01 | E-GEOD-49079 | biostudies-arrayexpress
Project description:GFAP and vimentin deficiency alters gene expression in astrocytes and microglia in wild-type mice and changes the transcriptional response of reactive glia in mouse model for Alzheimer's disease. Reactive astrocytes with an increased expression of intermediate filament (IF) proteins Glial Fibrillary Acidic Protein (GFAP) and Vimentin (VIM) surround amyloid plaques in Alzheimer's disease (AD). The functional consequences of this upregulation are unclear. To identify molecular pathways coupled to IF regulation in reactive astrocytes, and to study the interaction with microglia, we examined WT and APPswe/PS1dE9 (AD) mice lacking either GFAP, or both VIM and GFAP, and determined the transcriptome of cortical astrocytes and microglia from 15- to 18-month-old mice. Genes involved in lysosomal degradation (including several cathepsins) and in inflammatory response (including Cxcl5, Tlr6, Tnf, Il1b) exhibited a higher AD-induced increase when GFAP, or VIM and GFAP, were absent. The expression of Aqp4 and Gja1 displayed the same pattern. The downregulation of neuronal support genes in astrocytes from AD mice was absent in GFAP/VIM null mice. In contrast, the absence of IFs did not affect the transcriptional alterations induced by AD in microglia, nor was the cortical plaque load altered. Visualizing astrocyte morphology in GFAP-eGFP mice showed no clear structural differences in GFAP/VIM null mice, but did show diminished interaction of astrocyte processes with plaques. Microglial proliferation increased similarly in all AD groups. In conclusion, absence of GFAP, or both GFAP and VIM, alters AD-induced changes in gene expression profile of astrocytes, showing a compensation of the decrease of neuronal support genes and a trend for a slightly higher inflammatory expression profile. However, this has no consequences for the development of plaque load, microglial proliferation, or microglial activation. 2 cell types from 6 conditions: cortical microglia and cortical astrocytes from 15-18 month old APPswe/PS1dE9 mice compared to wildtype littermates. Biological replicates: microglia from APPswe/PS1dE9, N=7, microglia from WT, N=7, astrocytes from APPswe/PS1dE9, N=4, microglia from WT, N=4
2015-11-04 | E-GEOD-74614 | biostudies-arrayexpress
Project description:Early-life stress (ELS) leads to increased vulnerability to psychiatric illness including cognitive impairment later in life. Neuroinflammatory processes have been implicated in ELS-induced negative health outcomes, but, how ELS impacts microglia, the macrophages of the central nervous system, is unknown. Here, we determined the effects of ELS induced by limited bedding and nesting material during the first week of life (P2 – P9) on the morphology and gene expression of microglia from young (postnatal day (P)9) and adult (P200) mice. ELS led to a change in the proportion of morphological microglia subtypes in adulthood, associated with immune reactivity. At the transcriptional level, whereas at P9 no ELS mediated changes were detected, at P200 ELS induced transcriptional changes in microglia genes involved in the immune response and protein ubiquitination. Additionally, ELS altered microglia gene expression changes during development from P9 to P200 and in response to LPS at P200, in both cases marked by GO-terms associated with the immune response. Concluding, these data show that ELS has persistent effects on the morphology and gene expression program of microglia and results in an altered transcriptional response to a systemic LPS challenge.
2022-12-14 | GSE207067 | GEO
Project description:Expression profiling by high throughput sequencing Microglial cells have a double life as the immune cells of the brain in times of stress but have also specific physiological functions in homeostatic conditions. In pathological contexts, microglia undergo a phenotypic switch called “reaction” ’that promotes the initiation and the propagation of neuro-inflammation. Reaction is complex, molecularly heterogeneous and still poorly characterized, leading to the concept that microglial reactivity might be too diverse to be molecularly defined. However, it remains unknown whether reactive microglia from different pathological contexts share a common molecular signature. Using improved flow cytometry and RNAseq approaches we studied, with higher statistical power, the remodeling of microglia transcriptome in a mouse model of sepsis. Through bioinformatic comparison of our results with published datasets, we defined the microglial reactome as a set of genes discriminating reactive from homeostatic microglia. Ultimately, we identified a subset of 86 genes deregulated in both acute and neurodegenerative conditions. Our data provide a new comprehensive resource that includes functional analysis and specific molecular makers of microglial reaction which represent new tools for its unambiguous characterization.
2018-01-31 | GSE109834 | GEO
Project description:Background: Specific microglia responses are thought to contribute to the development and progression of neurodegenerative diseases, including Parkinson’s disease (PD). However, the phenotypic acquisition of microglial cells and their role during the underlying neuroinflammatory processes remain largely elusive. Here, according to the multiple-hit hypothesis, which stipulates that PD etiology is determined by a combination of genetics and various environmental risk factors, we investigate microglial transcriptional programs and morphological adaptations under PARK7/DJ-1 deficiency, a genetic cause of PD, during lipopolysaccharide (LPS)-induced inflammation. Methods: Using a combination of single-cell RNA-sequencing, bulk RNA-sequencing, multicolor flow cytometry and immunofluorescence analyses, we comprehensively compared microglial cell phenotypic characteristics in PARK7/DJ-1 knock-out (KO) with wildtype littermate mice following 6- or 24-hour intraperitoneal injection with LPS. In a translational approach, we conducted corresponding analyses in human PARK7/DJ-1 mutant induced pluripotent stem cell (iPSC)-derived microglia and murine bone marrow-derived macrophages (BMDMs). Results: By excluding the contribution of other immune brain resident and peripheral cells, we show that microglia acutely isolated from PARK7/DJ-1 KO mice display a distinct phenotype, specially related to type II interferon and DNA damage response signaling, when compared with wildtype microglia, in response to LPS. We also detected discrete signatures in human PARK7/DJ-1 mutant iPSC-derived microglia and BMDMs from PARK7/DJ-1 KO mice. These specific transcriptional signatures were reflected at the morphological level, with microglia in LPS-treated PARK7/DJ-1 KO mice showing a less amoeboid cell shape compared to wildtype mice, both at 6 and 24 hours after acute inflammation, as also observed in BMDMs. Conclusions: Taken together, our results show that, under inflammatory conditions, PARK7/DJ-1 deficiency skews microglia towards a distinct phenotype characterized by downregulation of genes involved in type II interferon signaling and a less prominent amoeboid morphology compared to wildtype microglia. These findings suggest that the underlying oxidative stress associated with the lack of PARK7/DJ-1 affects microglia neuroinflammatory responses, which may play a causative role in PD onset and progression.
2024-08-09 | GSE254687 | GEO
Project description:Background: Specific microglia responses are thought to contribute to the development and progression of neurodegenerative diseases, including Parkinson’s disease (PD). However, the phenotypic acquisition of microglial cells and their role during the underlying neuroinflammatory processes remain largely elusive. Here, according to the multiple-hit hypothesis, which stipulates that PD etiology is determined by a combination of genetics and various environmental risk factors, we investigate microglial transcriptional programs and morphological adaptations under PARK7/DJ-1 deficiency, a genetic cause of PD, during lipopolysaccharide (LPS)-induced inflammation. Methods: Using a combination of single-cell RNA-sequencing, bulk RNA-sequencing, multicolor flow cytometry and immunofluorescence analyses, we comprehensively compared microglial cell phenotypic characteristics in PARK7/DJ-1 knock-out (KO) with wildtype littermate mice following 6- or 24-hour intraperitoneal injection with LPS. For translational perspectives, we conducted corresponding analyses in human PARK7/DJ-1 mutant induced pluripotent stem cell (iPSC)-derived microglia and murine bone marrow-derived macrophages (BMDMs). Results: By excluding the contribution of other immune brain resident and peripheral cells, we show that microglia acutely isolated from PARK7/DJ-1 KO mice display a distinct phenotype, specially related to type II interferon and DNA damage response signaling, when compared with wildtype microglia, in response to LPS. We also detected discrete signatures in human PARK7/DJ-1 mutant iPSC-derived microglia and BMDMs from PARK7/DJ-1 KO mice. These specific transcriptional signatures were reflected at the morphological level, with microglia in LPS-treated PARK7/DJ-1 KO mice showing a less amoeboid cell shape compared to wildtype mice, both at 6 and 24 hours after acute inflammation, as also observed in BMDMs. Conclusions: Taken together, our results show that, under inflammatory conditions, PARK7/DJ-1 deficiency skews microglia towards a distinct phenotype characterized by downregulation of genes involved in type II interferon signaling and a less prominent amoeboid morphology compared to wildtype microglia. These findings suggest that the underlying oxidative stress associated with the lack of PARK7/DJ-1 affects microglia neuroinflammatory responses, which may play a causative role in PD onset and progression.
2024-08-09 | GSE256105 | GEO
Project description:Analysis of LRRK2-regulation of microglia responce to the LPS at gene expression level. The hypothesis tested in the present study was whether LRRK2 influence the microglial phagocytosis- and neuroinflammation- related gene expression at mRNA level. Total RNA obtained from microglia cells isolated from Ntg or LRRK2KO mouse brain subjected to 6 or 24 hours of LPS treatment in vitro
2016-06-22 | E-GEOD-83562 | biostudies-arrayexpress
Project description:Spinal microglia play a pivotal role in the development of neuropathic pain. Peripheral nerve injury induces changes in the transcriptional profile of microglia, including increased expression of components of translational machinery. Whether microglial protein synthesis is stimulated following nerve injury and has a functional role in mediating pain hypersensitivity is unknown. Here, we show that nascent protein synthesis is upregulated in spinal microglia following peripheral nerve injury. Stimulating mRNA translation in microglia, via selective ablation of the translational repressor, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), promoted the transition of microglia to a reactive state and induced mechanical hypersensitivity. Conversely, inhibiting microglial translation by expressing mutant 4E-BP1 in microglia attenuated their peripheral nerve injury-induced activation and alleviated neuropathic pain. Thus, the stimulation of 4E-BP1-dependent translation promotes microglia reactivity and mechanical hypersensitivity, whereas its inhibition alleviates neuropathic pain.
2024-01-31 | GSE254472 | GEO
Project description:Curcumin is a potent modulator of the inflammatory transcriptome in microglia We have performed global gene expression analysis of BV-2 microglial cells under the following conditions: untreated, 20 µM Curcumin-treated, 100ng/ml LPS-treated, or 20 µM Curcumin-treated + 100ng/ml LPS-treated
2010-09-29 | E-GEOD-23639 | biostudies-arrayexpress