scholarly journals MCAM/CD146 Signaling via PLCγ1 Leads to Activation of β1-Integrins in Memory T-Cells Resulting in Increased Brain Infiltration

2020 ◽  
Vol 11 ◽  
Author(s):  
Lisa Zondler ◽  
Sebastian Herich ◽  
Petra Kotte ◽  
Katharina Körner ◽  
Tilman Schneider-Hohendorf ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Central Nervous System ◽  
T Cells ◽  
Nervous System ◽  
Immune Cells ◽  
Β1 Integrin ◽  
Integrin Activation ◽  
The Central Nervous System

Multiple sclerosis is a chronic auto-inflammatory disease of the central nervous system affecting patients worldwide. Neuroinflammation in multiple sclerosis is mainly driven by peripheral immune cells which invade the central nervous system and cause neurodegenerative inflammation. To enter the target tissue, immune cells have to overcome the endothelium and transmigrate into the tissue. Numerous molecules mediate this process and, as they determine the tissue invasiveness of immune cells, display great therapeutic potential. Melanoma cell adhesion molecule (MCAM) is a membrane-anchored glycoprotein expressed by a subset of T-cells and MCAM+ T-cells have been shown to contribute to neuroinflammation in multiple sclerosis. The role of the MCAM molecule for brain invasion, however, remained largely unknown. In order to investigate the role of the MCAM molecule on T-cells, we used different in vitro and in vivo assays, including ex vivo flow chambers, biochemistry and microscopy experiments of the mouse brain. We demonstrate that MCAM directly mediates adhesion and that the engagement of MCAM induces intracellular signaling leading to β1-integrin activation on human T-cells. Furthermore, we show that MCAM engagement triggers the phosphorylation of PLCγ1 which is required for integrin activation and thus amplification of the cellular adhesive potential. To confirm the physiological relevance of our findings in vivo, we demonstrate that MCAM plays an important role in T-cell recruitment into the mouse brain. In conclusion, our data demonstrate that MCAM expressed on T-cells acts as an adhesion molecule and a signaling receptor that may trigger β1-integrin activation via PLCγ1 upon engagement.

scholarly journals Activated mouse astrocytes and T cells express similar CD44 variants. Role of CD44 in astrocyte/T cell binding

1993 ◽  
Vol 122 (5) ◽  
pp. 1067-1077 ◽  
Author(s):  
H Haegel ◽  
C Tölg ◽  
M Hofmann ◽  
R Ceredig
Keyword(s):  
Multiple Sclerosis ◽  
Central Nervous System ◽  
T Cells ◽  
Nervous System ◽  
T Cell ◽  
Primary Cultures ◽  
Cell Types ◽  
Mrna Levels ◽  
The Central Nervous System

The CD44 adhesion molecule is expressed by astrocytes, glial-type cells which exhibit features of accessory cells for immune responses in the central nervous system. In primary cultures of mouse astrocytes, we have observed that surface expression and mRNA levels of CD44 are induced following stimulation with either PMA, or tumor necrosis factor alpha plus gamma interferon. Comparison of CD44 splice variants expressed by astrocytes and a T cell hybridoma shows that upon activation, both cell types express a similar pattern of CD44 transcripts. Thus, in both cell types, CD44 transcripts are produced which contain additional exons, including the exon v6 (known to be expressed by in vivo activated lymphocytes and by metastatic variants of tumor cells) as well as variants of larger size. In the autoimmune disease multiple sclerosis, activated T cells cross the blood-brain barrier and lead to inflammation in the central nervous system. Analysis of mice with experimental allergic encephalomyelitis, frequently used as an animal model of multiple sclerosis, shows that CD44 is induced in vivo on glial cells surrounding inflammatory lesions. Using an in vitro model for adhesion between T cells and astrocytes, we have found a correlation between the activation state of these cells and their adhesion potential. Dose-dependent inhibition of adhesion by hyaluronate and by anti-CD44 monoclonal antibody KM81 shows that CD44 is involved in the adhesive interactions between T cells and astrocytes.

scholarly journals Multiple Sclerosis and the Blood-Central Nervous System Barrier

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Alan M. Palmer
Keyword(s):  
Multiple Sclerosis ◽  
Central Nervous System ◽  
Nervous System ◽  
Immune Cells ◽  
Cannabinoid Receptors ◽  
Humanized Monoclonal Antibody ◽  
The Central Nervous System ◽  
Cns Side Effects ◽  
Cell Adhesion Molecule 1

The central nervous system (CNS) is isolated from the blood system by a physical barrier that contains efflux transporters and catabolic enzymes. This blood-CNS barrier (BCNSB) plays a pivotal role in the pathophysiology of multiple sclerosis (MS). It binds and anchors activated leukocytes to permit their movement across the BCNSB and into the CNS. Once there, these immune cells target particular self-epitopes and initiate a cascade of neuroinflammation, which leads to the breakdown of the BCNSB and the formation of perivascular plaques, one of the hallmarks of MS. Immunomodulatory drugs for MS are either biologics or small molecules, with only the latter having the capacity to cross the BCNSB and thus have a propensity to cause CNS side effects. However, BCNSB penetration is a desirable feature of MS drugs that have molecular targets within the CNS. These are nabiximols and dalfampridine, which target cannabinoid receptors and potassium channels, respectively. Vascular cell adhesion molecule-1, present on endothelial cells of the BCNSB, also serves as a drug discovery target since it interacts with α4-β1-integrin on leucocytes. The MS drug natalizumab, a humanized monoclonal antibody against α4-β1-integrin, blocks this interaction and thus reduces the movement of immune cells into the CNS. This paper further elaborates on the role of the BCNSB in the pathophysiology and pharmacotherapy of MS.

scholarly journals TGF-β in Mice Ameliorates Experimental Autoimmune Encephalomyelitis in Regulating NK Cell Activity

2019 ◽  
Vol 28 (9-10) ◽  
pp. 1155-1160 ◽  
Author(s):  
J. Xu ◽  
Y. Wang ◽  
H. Jiang ◽  
M. Sun ◽  
J. Gao ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Central Nervous System ◽  
T Cells ◽  
Nervous System ◽  
Experimental Autoimmune Encephalomyelitis ◽  
Nk Cells ◽  
Nk Cell ◽  
Autoimmune Encephalomyelitis ◽  
The Central Nervous System ◽  
Experimental Autoimmune

Multiple sclerosis is a disease characterized by inflammation and demyelination located in the central nervous system. Experimental autoimmune encephalomyelitis (EAE) is the most common animal model for multiple sclerosis (MS). Although the roles of T cells in MS/EAE have been well investigated, little is known about the functions of other immune cells in the neuroinflammation model. Here we found that an essential cytokine transforming growth factor β (TGF-β) which could mediate the differentiation of Th17/regulatory T cells was implicated in the natural killer (NK) cells’ activity in EAE. In EAE mice, TGF-β expression was first increased at the onset and then decreased at the peak, but the expressions of TGF-β receptors and downstream molecules were not affected in EAE. When we immunized the mice with MOG antigen, it was revealed that TGF-β treatment reduced susceptibility to EAE with a lower clinical score than the control mice without TGF-β. Consistently, inflammatory cytokine production was reduced in the TGF-β treated group, especially with downregulated pathogenic interleukin-17 in the central nervous system tissue. Furthermore, TGF-β could increase the transcription level of NK cell marker NCR1 both in the spleen and in the CNS without changing other T cell markers. Meanwhile TGF-β promoted the proliferation of NK cell proliferation. Taken together, our data demonstrated that TGF-β could confer protection against EAE model in mice through NK cells, which would be useful for the clinical therapy of MS.

Role of inflammation and apoptosis in multiple sclerosis: Comparative analysis between the periphery and the central nervous system

2015 ◽  
Vol 287 ◽  
pp. 80-87 ◽  
Author(s):  
Beatrice Macchi ◽  
Francesca Marino-Merlo ◽  
Ugo Nocentini ◽  
Valerio Pisani ◽  
Salvatore Cuzzocrea ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Central Nervous System ◽  
Nervous System ◽  
Comparative Analysis ◽  
The Central Nervous System

scholarly journals Expanding Role of T Cells in Human Autoimmune Diseases of the Central Nervous System

2017 ◽  
Vol 8 ◽  
Author(s):  
Deepti Pilli ◽  
Alicia Zou ◽  
Fiona Tea ◽  
Russell C. Dale ◽  
Fabienne Brilot
Keyword(s):  
Central Nervous System ◽  
T Cells ◽  
Nervous System ◽  
Autoimmune Diseases ◽  
The Central Nervous System

scholarly journals The Role of Microglia during West Nile Virus Infection of the Central Nervous System

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 485 ◽  
Author(s):  
Sarah Stonedahl ◽  
Penny Clarke ◽  
Kenneth L. Tyler
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
West Nile Virus ◽  
Immune Cells ◽  
Neuronal Cell ◽  
The United States ◽  
Health Concern ◽  
West Nile ◽  
The Central Nervous System

Encephalitis resulting from viral infections is a major cause of hospitalization and death worldwide. West Nile Virus (WNV) is a substantial health concern as it is one of the leading causes of viral encephalitis in the United States today. WNV infiltrates the central nervous system (CNS), where it directly infects neurons and induces neuronal cell death, in part, via activation of caspase 3-mediated apoptosis. WNV infection also induces neuroinflammation characterized by activation of innate immune cells, including microglia and astrocytes, production of inflammatory cytokines, breakdown of the blood-brain barrier, and infiltration of peripheral leukocytes. Microglia are the resident immune cells of the brain and monitor the CNS for signs of injury or pathogens. Following infection with WNV, microglia exhibit a change in morphology consistent with activation and are associated with increased expression of proinflammatory cytokines. Recent research has focused on deciphering the role of microglia during WNV encephalitis. Microglia play a protective role during infections by limiting viral growth and reducing mortality in mice. However, it also appears that activated microglia are triggered by T cells to mediate synaptic elimination at late times during infection, which may contribute to long-term neurological deficits following a neuroinvasive WNV infection. This review will discuss the important role of microglia in the pathogenesis of a neuroinvasive WNV infection. Knowledge of the precise role of microglia during a WNV infection may lead to a greater ability to treat and manage WNV encephalitis.

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