scholarly journals Blood–brain barrier genetic disruption leads to protective barrier formation at the Glia Limitans

PLoS Biology ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. e3000946
Author(s):  
Pierre Mora ◽  
Pierre-Louis Hollier ◽  
Sarah Guimbal ◽  
Alice Abelanet ◽  
Aïssata Diop ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Blood Brain Barrier ◽  
Resting State ◽  
Brain Barrier ◽  
Protective Effects ◽  
Cns Inflammation ◽  
Glia Limitans ◽  
Protective Barrier ◽  
Blood Brain ◽  
Bbb Opening

Inflammation of the central nervous system (CNS) induces endothelial blood–brain barrier (BBB) opening as well as the formation of a tight junction barrier between reactive astrocytes at the Glia Limitans. We hypothesized that the CNS parenchyma may acquire protection from the reactive astrocytic Glia Limitans not only during neuroinflammation but also when BBB integrity is compromised in the resting state. Previous studies found that astrocyte-derived Sonic hedgehog (SHH) stabilizes the BBB during CNS inflammatory disease, while endothelial-derived desert hedgehog (DHH) is expressed at the BBB under resting conditions. Here, we investigated the effects of endothelial Dhh on the integrity of the BBB and Glia Limitans. We first characterized DHH expression within endothelial cells at the BBB, then demonstrated that DHH is down-regulated during experimental autoimmune encephalomyelitis (EAE). Using a mouse model in which endothelial Dhh is inducibly deleted, we found that endothelial Dhh both opens the BBB via the modulation of forkhead box O1 (FoxO1) transcriptional activity and induces a tight junctional barrier at the Glia Limitans. We confirmed the relevance of this glial barrier system in human multiple sclerosis active lesions. These results provide evidence for the novel concept of “chronic neuroinflammatory tolerance” in which BBB opening in the resting state is sufficient to stimulate a protective barrier at the Glia Limitans that limits the severity of subsequent neuroinflammatory disease. In summary, genetic disruption of the BBB generates endothelial signals that drive the formation under resting conditions of a secondary barrier at the Glia Limitans with protective effects against subsequent CNS inflammation. The concept of a reciprocally regulated CNS double barrier system has implications for treatment strategies in both the acute and chronic phases of multiple sclerosis pathophysiology.

scholarly journals Genetic disruption of the Blood Brain Barrier leads to protective barrier formation at the Glia Limitans

2020 ◽  
Author(s):  
Pierre-Louis Hollier ◽  
Sarah Guimbal ◽  
Pierre Mora ◽  
Aïssata Diop ◽  
Lauriane Cornuault ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Tight Junction ◽  
Blood Brain Barrier ◽  
Treatment Strategies ◽  
Brain Barrier ◽  
Double Barrier ◽  
Cns Inflammation ◽  
Glia Limitans ◽  
Inflammatory Conditions ◽  
Blood Brain

AbstractRecent work demonstrated that Central Nervous System (CNS) inflammation induces endothelial Blood Brain Barrier (BBB) opening as well as the formation of a tight junction barrier between reactive astrocytes at the Glia Limitans. We hypothesized that these two barriers may be reciprocally regulated by each other state and further, that the CNS parenchyma may acquire protection from the reactive astrocytic Glia Limitans not only in neuro-inflammation but also when BBB integrity is compromised under resting condition, without pathology. Previous studies identified Sonic hedgehog (Shh) astrocytic secretion as implicated in stabilizing the BBB during neuropathology and we recently demonstrated that desert hedgehog (Dhh) is expressed at the BBB in adults.Here we unraveled the role of the morphogen Dhh in maintaining BBB tightness and, using endothelial Dhh knockdown as a model of permeable BBB, we demonstrated that a double barrier system comprising both the BBB and Glia Limitans, is implemented in the CNS and regulated by a crosstalk going from endothelial cell to astrocytes.First, we showed that, under neuro-inflammatory conditions, Dhh expression is severely down regulated at the BBB and that Dhh is necessary for endothelial intercellular junction integrity as Dhh knockdown leads to CNS vascular leakage. We then demonstrated that, in Dhh endothelial knockout (DhhECKO) mice which display an open BBB, astrocytes are reactive and express the tight junction Claudin 4 (Cldn4) and showed that astrocytes can respond to signals secreted by the permeable endothelial BBB by becoming reactive and expressing Cldn4. To examine the consequences of the above results on disease severity, we finally induced multiple sclerosis in DhhECKO mice versus control littermates and showed that the pathology is less severe in the knockout animals due to Glia Limitans tightening, in response to BBB leakage, which drives inflammatory infiltrate entrapment into the perivascular space. Altogether these results suggest that genetic disruption of the BBB generates endothelial signals capable of driving the implementation of a secondary barrier at the Glia Limitans to protect the parenchyma. The concept of a reciprocally regulated CNS double barrier system has implications for treatment strategies in both the acute and chronic phases of multiple sclerosis pathophysiology.

Neurofilament levels are associated with blood–brain barrier integrity, lymphocyte extravasation, and risk factors following the first demyelinating event in multiple sclerosis

2020 ◽  
pp. 135245852091237 ◽  
Author(s):  
Tomas Uher ◽  
Mason McComb ◽  
Shery Galkin ◽  
Barbora Srpova ◽  
Johanna Oechtering ◽  
...  
Keyword(s):  
Risk Factors ◽  
Multiple Sclerosis ◽  
Blood Brain Barrier ◽  
Immune Cell ◽  
Disease Onset ◽  
Cell Subset ◽  
Immunoglobulin M ◽  
Brain Barrier ◽  
Cns Inflammation ◽  
Blood Brain

Background: Increased blood brain barrier (BBB) permeability, CNS inflammation and neuroaxonal damage are pathological hallmarks in early multiple sclerosis (MS). Objective: To investigate the associations of neurofilament light chain (NfL) levels with measures of BBB integrity and central nervous system (CNS) inflammation in MS during the first demyelinating event. Methods: Blood and cerebrospinal fluid (CSF) were obtained from 142 MS (McDonald 2017) treatment-naive patients from the SET study (63% female; age: 29.7 ± 7.9 years) following the disease onset. NfL, albumin, immunoglobulin G (IgG), and immunoglobulin M (IgM) levels were measured in CSF and blood samples. Albumin quotient was computed as a marker of BBB integrity. Immune cell subset counts in CSF were measured using flow cytometry. MS risk factors, such as Human leukocyte antigen DRB1 locus gene ( HLA DRB1)*1501, anti-Epstein–Barr virus (EBV) antibodies, and 25-hydroxy vitamin D3, were also measured. Results: Higher serum NfL (sNfL) levels were associated with higher albumin quotient ( p < 0.001), CSF CD80+ ( p = 0.012), and CD80+ CD19+ ( p = 0.015) cell frequency. sNfL levels were also associated with contrast-enhancing and T2 lesions on brain magnetic resonance imaging (MRI; all p ⩽ 0.001). Albumin quotient was not associated with any of the MS risk factors assessed. sNfL levels were associated with anti-EBV viral capsid antigen (VCA) IgG levels ( p = 0.0026). Conclusion: sNfL levels during the first demyelinating event of MS are associated with greater impairment of BBB integrity, immune cell extravasation, and brain lesion activity on MRI.

scholarly journals Inhibitory Effect of Matrine on Blood-Brain Barrier Disruption for the Treatment of Experimental Autoimmune Encephalomyelitis

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Su Zhang ◽  
Quan-Cheng Kan ◽  
Yuming Xu ◽  
Guang-Xian Zhang ◽  
Lin Zhu
Keyword(s):  
Basement Membrane ◽  
Experimental Autoimmune Encephalomyelitis ◽  
Blood Brain Barrier ◽  
Adaptor Protein ◽  
Brain Barrier ◽  
Autoimmune Encephalomyelitis ◽  
Novel Therapy ◽  
Cns Inflammation ◽  
Blood Brain ◽  
Experimental Autoimmune

Dysfunction of the blood-brain barrier (BBB) is a primary characteristic of experimental autoimmune encephalomyelitis (EAE), an experimental model of multiple sclerosis (MS). Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flave, has been recently found to suppress clinical EAE and CNS inflammation. However, whether this effect of MAT is through protecting the integrity and function of the BBB is not known. In the present study, we show that MAT treatment had a therapeutic effect comparable to dexamethasone (DEX) in EAE rats, with reduced Evans Blue extravasation, increased expression of collagen IV, the major component of the basement membrane, and the structure of tight junction (TJ) adaptor protein Zonula occludens-1 (ZO-1). Furthermore, MAT treatment attenuated expression of matrix metalloproteinase-9 and -2 (MMP-9/-2), while it increased the expression of tissue inhibitors of metalloproteinase-1 and -2 (TIMP-1/-2). Our findings demonstrate that MAT reduces BBB leakage by strengthening basement membrane, inhibiting activities of MMP-2 and -9, and upregulating their inhibitors. Taken together, our results identify a novel mechanism underlying the effect of MAT, a natural compound that could be a novel therapy for MS.

scholarly journals Safety evaluation of a clinical focused ultrasound system for neuronavigation guided blood-brain barrier opening in non-human primates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antonios N. Pouliopoulos ◽  
Nancy Kwon ◽  
Greg Jensen ◽  
Anna Meaney ◽  
Yusuke Niimi ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Safety Profile ◽  
Focused Ultrasound ◽  
Multiple Case Study ◽  
Brain Barrier ◽  
Non Invasive ◽  
Blood Brain ◽  
Multiple Case ◽  
Bbb Opening

AbstractAn emerging approach with potential in improving the treatment of neurodegenerative diseases and brain tumors is the use of focused ultrasound (FUS) to bypass the blood–brain barrier (BBB) in a non-invasive and localized manner. A large body of pre-clinical work has paved the way for the gradual clinical implementation of FUS-induced BBB opening. Even though the safety profile of FUS treatments in rodents has been extensively studied, the histological and behavioral effects of clinically relevant BBB opening in large animals are relatively understudied. Here, we examine the histological and behavioral safety profile following localized BBB opening in non-human primates (NHPs), using a neuronavigation-guided clinical system prototype. We show that FUS treatment triggers a short-lived immune response within the targeted region without exacerbating the touch accuracy or reaction time in visual-motor cognitive tasks. Our experiments were designed using a multiple-case-study approach, in order to maximize the acquired data and support translation of the FUS system into human studies. Four NHPs underwent a single session of FUS-mediated BBB opening in the prefrontal cortex. Two NHPs were treated bilaterally at different pressures, sacrificed on day 2 and 18 post-FUS, respectively, and their brains were histologically processed. In separate experiments, two NHPs that were earlier trained in a behavioral task were exposed to FUS unilaterally, and their performance was tracked for at least 3 weeks after BBB opening. An increased microglia density around blood vessels was detected on day 2, but was resolved by day 18. We also detected signs of enhanced immature neuron presence within areas that underwent BBB opening, compared to regions with an intact BBB, confirming previous rodent studies. Logistic regression analysis showed that the NHP cognitive performance did not deteriorate following BBB opening. These preliminary results demonstrate that neuronavigation-guided FUS with a single-element transducer is a non-invasive method capable of reversibly opening the BBB, without substantial histological or behavioral impact in an animal model closely resembling humans. Future work should confirm the observations of this multiple-case-study work across animals, species and tasks.

scholarly journals Vascular pathology in multiple sclerosis: reframing pathogenesis around the blood-brain barrier

2017 ◽  
Vol 89 (1) ◽  
pp. 42-52 ◽  
Author(s):  
Jonathan I Spencer ◽  
Jack S Bell ◽  
Gabriele C DeLuca
Keyword(s):  
Multiple Sclerosis ◽  
Immune Response ◽  
Blood Brain Barrier ◽  
Immune Cell ◽  
Neurological Diseases ◽  
Specific Immune Response ◽  
Brain Barrier ◽  
Vascular Pathology ◽  
Current Evidence ◽  
Blood Brain

Blood-brain barrier (BBB) disruption has long been recognised as an important early feature of multiple sclerosis (MS) pathology. Traditionally, this has been seen as a by-product of the myelin-specific immune response. Here, we consider whether vascular changes instead play a central role in disease pathogenesis, rather than representing a secondary effect of neuroinflammation or neurodegeneration. Importantly, this is not necessarily mutually exclusive from current hypotheses. Vascular pathology in a genetically predisposed individual, influenced by environmental factors such as pathogens, hypovitaminosis D and smoking, may be a critical initiator of a series of events including hypoxia, protein deposition and immune cell egress that allows the development of a CNS-specific immune response and the classical pathological and clinical hallmarks of disease. We review the changes that occur in BBB function and cerebral perfusion in patients with MS and highlight genetic and environmental risk factors that, in addition to modulating immune function, may also converge to act on the vasculature. Further context is provided by contrasting these changes with other neurological diseases in which there is also BBB malfunction, and highlighting current disease-modifying therapies that may also have an effect on the BBB. Indeed, in reframing current evidence in this model, the vasculature could become an important therapeutic target in MS.

BREAKDOWN OF THE BLOOD-BRAIN BARRIER PRECEDES SYMPTOMS AND OTHER MRI SIGNS OF NEW LESIONS IN MULTIPLE SCLEROSIS

Brain ◽  
1990 ◽  
Vol 113 (5) ◽  
pp. 1477-1489 ◽  
Author(s):  
A. G. KERMODE ◽  
A. J. THOMPSON ◽  
P. TOFTS ◽  
D. G. MACMANUS ◽  
B. E. KENDALL ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Blood Brain
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