EBI2 Is Temporarily Upregulated in MO3.13 Oligodendrocytes during Maturation and Regulates Remyelination in the Organotypic Cerebellar Slice Model

The EBI2 receptor regulates the immune system and is expressed in various immune cells including B and T lymphocytes. It is also expressed in astrocytes in the central nervous system (CNS) where it regulates pro-inflammatory cytokine release, cell migration and protects from chemically induced demyelination. Its signaling and expression are implicated in various diseases including multiple sclerosis, where its expression is increased in infiltrating immune cells in the white matter lesions. Here, for the first time, the EBI2 protein in the CNS cells in the human brain was examined. The function of the receptor in MO3.13 oligodendrocytes, as well as its role in remyelination in organotypic cerebellar slices, were investigated. Human brain sections were co-stained for EBI2 receptor and various markers of CNS-specific cells and the human oligodendrocyte cell line MO3.13 was used to investigate changes in EBI2 expression and cellular migration. Organotypic cerebellar slices prepared from wild-type and cholesterol 25-hydroxylase knock-out mice were used to study remyelination following lysophosphatidylcholine (LPC)-induced demyelination. The data showed that EBI2 receptor is present in OPCs but not in myelinating oligodendrocytes in the human brain and that EBI2 expression is temporarily upregulated in maturing MO3.13 oligodendrocytes. Moreover, we show that migration of MO3.13 cells is directly regulated by EBI2 and that its signaling is necessary for remyelination in cerebellar slices post-LPC-induced demyelination. The work reported here provides new information on the expression and role of EBI2 in oligodendrocytes and myelination and provides new tools for modulation of oligodendrocyte biology and therapeutic approaches for demyelinating diseases.

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Loss of microglial SIRPα promotes synaptic pruning in preclinical models of neurodegeneration

Nature Communications ◽

10.1038/s41467-021-22301-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Xin Ding ◽

Jin Wang ◽

Miaoxin Huang ◽

Zhangpeng Chen ◽

Jing Liu ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Knock Out ◽

Classical Complement Pathway ◽

Synaptic Remodeling ◽

The Central Nervous System ◽

System Activation ◽

Knock Out Mice ◽

Synaptic Pruning

AbstractMicroglia play a key role in regulating synaptic remodeling in the central nervous system. Activation of classical complement pathway promotes microglia-mediated synaptic pruning during development and disease. CD47 protects synapses from excessive pruning during development, implicating microglial SIRPα, a CD47 receptor, in synaptic remodeling. However, the role of microglial SIRPα in synaptic pruning in disease remains unclear. Here, using conditional knock-out mice, we show that microglia-specific deletion of SIRPα results in decreased synaptic density. In human tissue, we observe that microglial SIRPα expression declines alongside the progression of Alzheimer’s disease. To investigate the role of SIRPα in neurodegeneration, we modulate the expression of microglial SIRPα in mouse models of Alzheimer’s disease. Loss of microglial SIRPα results in increased synaptic loss mediated by microglia engulfment and enhanced cognitive impairment. Together, these results suggest that microglial SIRPα regulates synaptic pruning in neurodegeneration.

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Deletion of Kif5c Does Not Alter Prion Disease Tempo or Spread in Mouse Brain

Viruses ◽

10.3390/v13071391 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1391

Author(s):

Brent Race ◽

Katie Williams ◽

Chase Baune ◽

James F. Striebel ◽

Clayton W. Winkler ◽

...

Keyword(s):

Prion Disease ◽

Molecular Motors ◽

Prion Diseases ◽

Mouse Strains ◽

Survival Times ◽

Knock Out ◽

Transport Vesicles ◽

The Central Nervous System ◽

Knock Out Mice ◽

Scrapie Strains

In prion diseases, the spread of infectious prions (PrPSc) is thought to occur within nerves and across synapses of the central nervous system (CNS). However, the mechanisms by which PrPSc moves within axons and across nerve synapses remain undetermined. Molecular motors, including kinesins and dyneins, transport many types of intracellular cargo. Kinesin-1C (KIF5C) has been shown to transport vesicles carrying the normal prion protein (PrPC) within axons, but whether KIF5C is involved in PrPSc axonal transport is unknown. The current study tested whether stereotactic inoculation in the striatum of KIF5C knock-out mice (Kif5c−/−) with 0.5 µL volumes of mouse-adapted scrapie strains 22 L or ME7 would result in an altered rate of prion spreading and/or disease timing. Groups of mice injected with each strain were euthanized at either pre-clinical time points or following the development of prion disease. Immunohistochemistry for PrP was performed on brain sections and PrPSc distribution and tempo of spread were compared between mouse strains. In these experiments, no differences in PrPSc spread, distribution or survival times were observed between C57BL/6 and Kif5c−/− mice.

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IL17A Depletion Affects the Metabolism of Macrophages Treated with Gemcitabine

Antioxidants ◽

10.3390/antiox10030422 ◽

2021 ◽

Vol 10 (3) ◽

pp. 422

Author(s):

Cecilia Roux ◽

Gianluca Mucciolo ◽

Joanna Kopecka ◽

Francesco Novelli ◽

Chiara Riganti ◽

...

Keyword(s):

Pancreatic Cancer ◽

Immune Cells ◽

Stromal Cells ◽

Gold Standard ◽

Tumor Response ◽

Proof Of Concept ◽

Macrophage Differentiation ◽

Standard Drug ◽

Knock Out ◽

Knock Out Mice

Background: Interleukin (IL)17A is a member of the IL17 cytokine family, which is released by both immune and non-immune cells such as tumor and stromal cells into the tumor microenvironment. IL17 receptors are also widely expressed in different type of cells. Among all the members, IL17A is the most controversial in regulating tumor immunity. Here, we investigated how IL17A inhibition modulated macrophage differentiation and metabolism in the presence or absence of gemcitabine. Gemcitabine is the gold standard drug for treating pancreatic cancer and can increase macrophage antitumoral activities. Results: We observed some unique features of macrophages polarized in the absence of IL17A, in terms of RNA and protein expression of typical phenotypic markers, and we demonstrated that this paralleled specific changes in their metabolism and functions, such as the induction of an antitumor response. Interestingly, these features were almost maintained or enhanced when macrophages were treated with gemcitabine. We also demonstrated that the anti-IL17A antibody effectively reproduced features of macrophages derived from IL17A knock-out mice. Conclusion: Overall, we provide a proof-of-concept that combining an anti-IL17A antibody with gemcitabine may represent an effective strategy to modulate macrophages and enhance the anti-tumor response, especially in pancreatic cancer where gemcitabine is widely used.

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The role of P2Y12 in the kinetics of microglial self-renewal and maturation in the adult visual cortex in vivo

eLife ◽

10.7554/elife.61173 ◽

2021 ◽

Vol 10 ◽

Author(s):

Monique Mendes ◽

Linh Le ◽

Jason Atlas ◽

Zachary Brehm ◽

Antonio Ladron-de-Guevara ◽

...

Keyword(s):

Immune Cells ◽

Self Renewal ◽

Knock Out ◽

Two Photon ◽

And Migration ◽

Knock Out Mice ◽

Morphological Maturation ◽

Kinetics Of

Microglia are the brain's resident immune cells with a tremendous capacity to autonomously self-renew. Because microglial self-renewal has largely been studied using static tools, its mechanisms and kinetics are not well understood. Using chronic in vivo two-photon imaging in awake mice, we confirm that cortical microglia show limited turnover and migration under basal conditions. Following depletion, however, microglial repopulation is remarkably rapid and is sustained by the dynamic division of remaining microglia, in a manner that is largely independent of signaling through the P2Y12 receptor. Mathematical modeling of microglial division demonstrates that the observed division rates can account for the rapid repopulation observed in vivo. Additionally, newly-born microglia resemble mature microglia within days of repopulation, although morphological maturation is different in newly born microglia in P2Y12 knock out mice. Our work suggests that microglia rapidly locally and that newly-born microglia do not recapitulate the slow maturation seen in development but instead take on mature roles in the CNS.

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NF-kappaB activity in transgenic mice: developmental regulation and tissue specificity

Development ◽

10.1242/dev.122.7.2117 ◽

1996 ◽

Vol 122 (7) ◽

pp. 2117-2128 ◽

Cited By ~ 3

Author(s):

R. Schmidt-Ullrich ◽

S. Memet ◽

A. Lilienbaum ◽

J. Feuillard ◽

M. Raphael ◽

...

Keyword(s):

Transgenic Mice ◽

Early Development ◽

Developmental Regulation ◽

Mouse Development ◽

Knock Out ◽

Cellular Genes ◽

Development And Differentiation ◽

The Central Nervous System ◽

Nf Kappab ◽

Knock Out Mice

The transcription factor family NF-kappaB/Rel is responsible for the regulation of a large number of cellular genes and some viruses. Since there is a strong similarity between the NF-kappaB/Rel family members and the Drosophila melanogaster protein DORSAL, which is activated early during embryogenesis, we were interested in determining the pattern of NF-kappaB activity during mouse development. Two lacZ reporter constructs, each driven by promoter elements that are dependent on the presence of nuclear NF-kappaB/Rel activity, were used to produce transgenic mice. The analysis of these mice did not identify nuclear NF-kappaB/Rel activity in early development prior to implantation or during the gastrulation processes. Earliest expression of the lacZ transgene was detected on day E12.5. Before birth lacZ expression was seen in discrete regions of the rhombencephalon of the developing brain, in the spinal medulla, in some of the blood vessels and in the thymus. After birth, the NF-kappaB/Rel activity in the thymus remained but nuclear activity was also found in the bone marrow, in the spleen and in the capsule of the lymph nodes. In the central nervous system, drastic changes in NF-kappaB/Rel activity could be observed in the first 3 weeks after birth, when the cortex and the cerebellum reach functional and morphological maturity. Considering the results of the p50, p65, relB and c-rel knock-out mice and our present findings, we believe that the NF-kappaB/Rel proteins known so far are probably not implicated in processes of early development and differentiation of the different tissues, but rather in maintaining their function once matured.

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