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Brandi E, Torres-Garcia L, Svanbergsson A, Haikal C, Liu D, Li W, Li JY. Brain region-specific microglial and astrocytic activation in response to systemic lipopolysaccharides exposure. Front Aging Neurosci 2022; 14:910988. [PMID: 36092814 PMCID: PMC9459169 DOI: 10.3389/fnagi.2022.910988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/26/2022] [Indexed: 11/24/2022] Open
Abstract
Microglia cells are the macrophage population within the central nervous system, which acts as the first line of the immune defense. These cells present a high level of heterogeneity among different brain regions regarding morphology, cell density, transcriptomes, and expression of different inflammatory mediators. This region-specific heterogeneity may lead to different neuroinflammatory responses, influencing the regional involvement in several neurodegenerative diseases. In this study, we aimed to evaluate microglial response in 16 brain regions. We compared different aspects of the microglial response, such as the extension of their morphological changes, sensitivity, and ability to convert an acute inflammatory response to a chronic one. Then, we investigated the synaptic alterations followed by acute and chronic inflammation in substantia nigra. Moreover, we estimated the effect of partial ablation of fractalkine CX3C receptor 1 (CX3CR1) on microglial response. In the end, we briefly investigated astrocytic heterogeneity and activation. To evaluate microglial response in different brain regions and under the same stimulus, we induced a systemic inflammatory reaction through a single intraperitoneal (i.p.) injection of lipopolysaccharides (LPS). We performed our study using C57BL6 and CX3CR1+/GFP mice to investigate microglial response in different regions and the impact of CX3CR1 partial ablation. We conducted a topographic study quantifying microglia alterations in 16 brain regions through immunohistochemical examination and computational image analysis. Assessing Iba1-immunopositive profiles and the density of the microglia cells, we have observed significant differences in region-specific responses of microglia populations in all parameters considered. Our results underline the peculiar microglial inflammation in the substantia nigra pars reticulata (SNpr). Here and in concomitance with the acute inflammatory response, we observed a transient decrease of dopaminergic dendrites and an alteration of the striato-nigral projections. Additionally, we found a significant decrease in microglia response and the absence of chronic inflammation in CX3CR1+/GFP mice compared to the wild-type ones, suggesting the CX3C axis as a possible pharmacological target against neuroinflammation induced by an increase of systemic tumor necrosis factor-alpha (TNFα) or/and LPS. Finally, we investigated astrocytic heterogeneity in this model. We observed different distribution and morphology of GFAP-positive astrocytes, a heterogeneous response under inflammatory conditions, and a decrease in their activation in CX3CR1 partially ablated mice compared with C57BL6 mice. Altogether, our data confirm that microglia and astrocytes heterogeneity lead to a region-specific inflammatory response in presence of a systemic TNFα or/and LPS treatment.
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Affiliation(s)
- Edoardo Brandi
- Neural Plasticity and Repair Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Laura Torres-Garcia
- Neural Plasticity and Repair Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Alexander Svanbergsson
- Neural Plasticity and Repair Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Caroline Haikal
- Neural Plasticity and Repair Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Di Liu
- Health Sciences Institute, China Medical University, Shenyang, China
| | - Wen Li
- Neural Plasticity and Repair Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Health Sciences Institute, China Medical University, Shenyang, China
| | - Jia-Yi Li
- Neural Plasticity and Repair Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Health Sciences Institute, China Medical University, Shenyang, China
- *Correspondence: Jia-Yi Li, ,
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Chen G, Shi F, Yin W, Guo Y, Liu A, Shuai J, Sun J. Gut microbiota dysbiosis: The potential mechanisms by which alcohol disrupts gut and brain functions. Front Microbiol 2022; 13:916765. [PMID: 35966709 PMCID: PMC9372561 DOI: 10.3389/fmicb.2022.916765] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/29/2022] [Indexed: 11/24/2022] Open
Abstract
Alcohol use disorder (AUD) is a high-risk psychiatric disorder and a key cause of death and disability in individuals. In the development of AUD, there is a connection known as the microbiota-gut-brain axis, where alcohol use disrupts the gut barrier, resulting in changes in intestinal permeability as well as the gut microbiota composition, which in turn impairs brain function and worsens the patient’s mental status and gut activity. Potential mechanisms are explored by which alcohol alters gut and brain function through the effects of the gut microbiota and their metabolites on immune and inflammatory pathways. Alcohol and microbiota dysregulation regulating neurotransmitter release, including DA, 5-HT, and GABA, are also discussed. Thus, based on the above discussion, it is possible to speculate on the gut microbiota as an underlying target for the treatment of diseases associated with alcohol addiction. This review will focus more on how alcohol and gut microbiota affect the structure and function of the gut and brain, specific changes in the composition of the gut microbiota, and some measures to mitigate the changes caused by alcohol exposure. This leads to a potential intervention for alcohol addiction through fecal microbiota transplantation, which could normalize the disruption of gut microbiota after AUD.
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Affiliation(s)
- Ganggang Chen
- Department of Anatomy and Neurobiology, School of Basic Medicine, Shandong University, Jinan, China
| | - Fenglei Shi
- Department of Othopaedics, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Wei Yin
- Department of Anatomy and Neurobiology, School of Basic Medicine, Shandong University, Jinan, China
| | - Yao Guo
- Shandong Provincial Mental Health Center, Jinan, China
| | - Anru Liu
- Department of Anatomy and Neurobiology, School of Basic Medicine, Shandong University, Jinan, China
| | - Jiacheng Shuai
- Department of Anatomy and Neurobiology, School of Basic Medicine, Shandong University, Jinan, China
| | - Jinhao Sun
- Department of Anatomy and Neurobiology, School of Basic Medicine, Shandong University, Jinan, China
- *Correspondence: Jinhao Sun,
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Chitu V, Biundo F, Stanley ER. Colony stimulating factors in the nervous system. Semin Immunol 2021; 54:101511. [PMID: 34743926 DOI: 10.1016/j.smim.2021.101511] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/23/2021] [Indexed: 01/02/2023]
Abstract
Although traditionally seen as regulators of hematopoiesis, colony-stimulating factors (CSFs) have emerged as important players in the nervous system, both in health and disease. This review summarizes the cellular sources, patterns of expression and physiological roles of the macrophage (CSF-1, IL-34), granulocyte-macrophage (GM-CSF) and granulocyte (G-CSF) colony stimulating factors within the nervous system, with a particular focus on their actions on microglia. CSF-1 and IL-34, via the CSF-1R, are required for the development, proliferation and maintenance of essentially all CNS microglia in a temporal and regional specific manner. In contrast, in steady state, GM-CSF and G-CSF are mainly involved in regulation of microglial function. The alterations in expression of these growth factors and their receptors, that have been reported in several neurological diseases, are described and the outcomes of their therapeutic targeting in mouse models and humans are discussed.
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Affiliation(s)
- Violeta Chitu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Fabrizio Biundo
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - E Richard Stanley
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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