scholarly journals Protective Role of Early Aquaporin 4 Induction against Postischemic Edema Formation

2008 ◽  
Vol 29 (2) ◽  
pp. 423-433 ◽  
Author(s):  
Lorenz Hirt ◽  
Béatrice Ternon ◽  
Melanie Price ◽  
Nabil Mastour ◽  
Jean-François Brunet ◽  
...  
Keyword(s):  
Water Channel ◽  
Protective Role ◽  
Aquaporin 4 ◽  
Late Time ◽  
Protective Mechanisms ◽  
Edema Formation ◽  
Aqp4 Expression ◽  
Blood Brain Barrier Disruption ◽  
Brain Barrier Disruption

Aquaporin 4 (AQP4) is a water channel involved in water movements across the cell membrane and is spatially organized on the cell surface in orthogonal array particles (OAPs). Its role in edema formation or resolution after stroke onset has been studied mainly at late time points. We have shown recently that its expression is rapidly induced after ischemia coinciding in time with an early swelling of the ischemic hemisphere. There are two isoforms of AQP4: AQP4-M1 and AQP4-M23. The ratio of these isoforms influences the size of the OAPs but the functional impact is not known. The role of the early induction of AQP4 is not yet known. Thrombin preconditioning in mice provides a useful model to study endogenous protective mechanisms. Using this model, we provide evidence for the first time that the early induction of AQP4 may contribute to limit the formation of edema and that the AQP4-M1 isoform is predominantly induced in the ischemic tissue at this time point. Although it prevents edema formation, the early induction of the AQP4 expression does not prevent the blood—brain barrier disruption, suggesting an effect limited to the prevention of edema formation possibly by removing of water from the tissue.

scholarly journals The Role of Urocortins in Intracerebral Hemorrhage

Biomolecules ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 96 ◽  
Author(s):  
Ker Woon Choy ◽  
Andy Po-Yi Tsai ◽  
Peter Bor-Chian Lin ◽  
Meng-Yu Wu ◽  
Chihyi Lee ◽  
...  
Keyword(s):  
Intracerebral Hemorrhage ◽  
Brain Regions ◽  
Brain Parenchyma ◽  
Protective Mechanisms ◽  
Neuroprotective Effects ◽  
Blood Brain Barrier Disruption ◽  
Brain Barrier Disruption ◽  
G Protein Coupled ◽  
The Brain

Intracerebral hemorrhage (ICH) causes an accumulation of blood in the brain parenchyma that disrupts the normal neurological function of the brain. Despite extensive clinical trials, no medical or surgical therapy has shown to be effective in managing ICH, resulting in a poor prognosis for the patients. Urocortin (UCN) is a 40-amino-acid endogenous neuropeptide that belongs to the corticotropin-releasing hormone (CRH) family. The effect of UCN is activated by binding to two G-protein coupled receptors, CRH-R1 and CRH-R2, which are expressed in brain neurons and glial cells in various brain regions. Current research has shown that UCN exerts neuroprotective effects in ICH models via anti-inflammatory effects, which generally reduced brain edema and reduced blood-brain barrier disruption. These effects gradually help in the improvement of the neurological outcome, and thus, UCN may be a potential therapeutic target in the treatment of ICH. This review summarizes the data published to date on the role of UCN in ICH and the possible protective mechanisms underlined.

scholarly journals Posttraumatic Reduction of Edema with Aquaporin-4 RNA Interference Improves Acute and Chronic Functional Recovery

2013 ◽  
Vol 33 (10) ◽  
pp. 1621-1632 ◽  
Author(s):  
Andrew M Fukuda ◽  
Arash Adami ◽  
Viorela Pop ◽  
John A Bellone ◽  
Jacqueline S Coats ◽  
...  
Keyword(s):  
Cell Death ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Aquaporin 4 ◽  
Edema Formation ◽  
Aqp4 Expression ◽  
Novel Treatments ◽  
Blood Brain Barrier Disruption ◽  
Neurologic Outcomes

Traumatic brain injury (TBI) is common in young children and adolescents and is associated with long-term disability and mortality. The neuropathologic sequelae that result from juvenile TBI are a complex cascade of events that include edema formation and brain swelling. Brain aquaporin-4 (AQP4) has a key role in edema formation. Thus, development of novel treatments targeting AQP4 to reduce edema could lessen the neuropathologic sequelae. We hypothesized that inhibiting AQP4 expression by injection of small-interfering RNA (siRNA) targeting AQP4 (siAQP4) after juvenile TBI would decrease edema formation, neuroinflammation, neuronal cell death, and improve neurologic outcomes. The siAQP4 or a RNA-induced silencing complex (RISC)-free control siRNA (siGLO) was injected lateral to the trauma site after controlled cortical impact in postnatal day 17 rats. Magnetic resonance imaging, neurologic testing, and immunohistochemistry were performed to assess outcomes. Pups treated with siAQP4 showed acute (3 days after injury) improvements in motor function and in spatial memory at long term (60 days after injury) compared with siGLO-treated animals. These improvements were associated with decreased edema formation, increased microglial activation, decreased blood–brain barrier disruption, reduced astrogliosis and neuronal cell death. The effectiveness of our treatment paradigm was associated with a 30% decrease in AQP4 expression at the injection site.

The treatment of brain metastasis from breast cancer, role of blood-brain barrier disruption and early experience with trastuzumab

Therapy ◽  
2006 ◽  
Vol 3 (1) ◽  
pp. 97-112 ◽  
Author(s):  
Rose Marie Tyson ◽  
Dale F Kraemer ◽  
Matthew A Hunt ◽  
Leslie L Muldoon ◽  
Peter Orbay ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Brain Metastasis ◽  
Blood Brain Barrier ◽  
Early Experience ◽  
Brain Barrier ◽  
Barrier Disruption ◽  
Blood Brain Barrier Disruption ◽  
Blood Brain ◽  
Brain Barrier Disruption

scholarly journals Aquaporin-4 Expression during Toxic and Autoimmune Demyelination

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2187
Author(s):  
Sven Olaf Rohr ◽  
Theresa Greiner ◽  
Sarah Joost ◽  
Sandra Amor ◽  
Paul van der Valk ◽  
...  
Keyword(s):  
Immune Cells ◽  
Water Channel ◽  
Staining Intensity ◽  
Brain Parenchyma ◽  
Aquaporin 4 ◽  
Aqp4 Expression ◽  
Humoral Immune ◽  
Autoimmune Demyelination ◽  
Peripheral Immune Cells ◽  
The Brain

The water channel protein aquaporin-4 (AQP4) is required for a normal rate of water exchange across the blood–brain interface. Following the discovery that AQP4 is a possible autoantigen in neuromyelitis optica, the function of AQP4 in health and disease has become a research focus. While several studies have addressed the expression and function of AQP4 during inflammatory demyelination, relatively little is known about its expression during non-autoimmune-mediated myelin damage. In this study, we used the toxin-induced demyelination model cuprizone as well as a combination of metabolic and autoimmune myelin injury (i.e., Cup/EAE) to investigate AQP4 pathology. We show that during toxin-induced demyelination, diffuse AQP4 expression increases, while polarized AQP4 expression at the astrocyte endfeet decreases. The diffuse increased expression of AQP4 was verified in chronic-active multiple sclerosis lesions. Around inflammatory brain lesions, AQP4 expression dramatically decreased, especially at sites where peripheral immune cells penetrate the brain parenchyma. Humoral immune responses appear not to be involved in this process since no anti-AQP4 antibodies were detected in the serum of the experimental mice. We provide strong evidence that the diffuse increase in anti-AQP4 staining intensity is due to a metabolic injury to the brain, whereas the focal, perivascular loss of anti-AQP4 immunoreactivity is mediated by peripheral immune cells.

Protective role of aquaporin-4 water channels after contusion spinal cord injury

2010 ◽  
pp. NA-NA ◽  
Author(s):  
Atsushi Kimura ◽  
Mike Hsu ◽  
Marcus Seldin ◽  
Alan S. Verkman ◽  
Helen E. Scharfman ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Water Channels ◽  
Protective Role ◽  
Aquaporin 4 ◽  
Cord Injury
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