Physiological Roles of Aquaporin-4 in Brain

Nagelhus, Erlend A.; Ottersen, Ole Petter

doi:10.1152/physrev.00011.2013

Cited by 594 publications

(570 citation statements)

References 213 publications

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“…Aquaporin 4 (AQP4) belongs to the subgroup of orthodox aquaporins responsible for transcellular transport of water only (Borgnia et al 1999). AQP4 is widely present in the brain, predominantly in astrocytes (Nagelhus and Ottersen 2013), however, recent findings documented AQP4-expression in the mammalian GIT. Thus, the most obvious and reasonable roles of AQP4 in GIT seem to be secretion and absorption which principally depend on the in and out transmembrane water flux.…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

2015

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The water channel aquaporin-4 (AQP4) is a protein widely expressed on plasma membrane of a variety of epithelial cells. In this study we investigated the expression of AQP4 in the gastrointestinal tract of the pig using immunohistochemical staining. We found no presence of AQP4 in the different regions of the pig stomach. In the porcine small intestine moderate immunoreactivity to AQP4 was detected in enterocytes (along the villi and in the bottom of the crypts), duodenal Brunner's glands and in enteric ganglia in cells lying in close vicinity to myenteric as well as submucous neurons. In superficial epithelial cells of the colonic mucosa as well as of caecal and colonic glands a very strong immunoreactivity to AQP4 was found. Both in the myenteric and submucous ganglia of the large intestine AQP4-positive cells surrounding enteric neurons were observed. We concluded that AQP4 expression in the porcine gastrointestinal tract showed some species-dependent differences in relation to other species. Based on the presented distribution pattern of AQP4, it is likely that the aquaporin plays a role in mucous (but not acid) secretion and intestinal absorptive processes in the pig. Aquaporins, gut, small intestine, large intestine, pig

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Section: Discussionmentioning

confidence: 99%

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

2015

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“…. There is no obvious explanation of the slight reduction in cortical glucose 22 levels, but one might speculate that astrocytic endfoot swelling observed in α-syn KO mice 23 [62] may reduce glucose transport into the brain. It is impossible to rule out a systemic effect 24 of α-syn KO on blood glucose levels and subsequently on cortical glucose levels, as blood 25 glucose was not measured in the current study where manipulation of the animals was kept to 1 a minimum to emulate the awake, resting state.…”

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confidence: 97%

Loss or Mislocalization of Aquaporin-4 Affects Diffusion Properties and Intermediary Metabolism in Gray Matter of Mice

et al. 2016

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1The first aim of this study was to determine how complete or perivascular loss of aquaporin-4 2 (AQP4) water channels affects membrane permeability for water in the mouse brain grey 3 matter in the steady state. Time-dependent diffusion magnetic resonance imaging was 4 performed on global Aqp4 knock out (KO) and α-syntrophin (α-syn) KO mice, in the latter 5 perivascular AQP4 are mislocalized, but still functioning. Control animals were 6 corresponding WT mice. By combining in vivo diffusion measurements with the effective 7 medium theory and previously-measured extra-cellular volume fractions, the effects of 8 membrane permeability and extracellular volume fraction were uncoupled for Aqp4 and α-9 syn KO. The second aim was to assess the effect of α-syn KO on cortical intermediary 10 metabolism combining in vivo [1-13 C]glucose and [1,2-13 C]acetate injection with ex vivo 13 C 11 MR spectroscopy. Aqp4 KO increased the effective diffusion coefficient at long diffusion 12 times by 5%, and a 14% decrease in membrane water permeability was estimated for

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“…Astrocytes extend dense, laminal processes that comprise the glial-limiting membrane, a selectively permeable structure that forms a boundary between CNS tissue and the cerebrospinal fluid in the subarachnoid spaces and throughout the ventricular system. 26 An additional barrier is formed by astrocytic "endfoot" processes juxtaposed to the cerebrovasculature, permitting the bidirectional communication between neurons and astrocytes in addition to enabling astrocytes to communicate with the supplying circulations of the blood and cerebrospinal fluid. 26,27 Paravascular astrocytic processes sheath 97% of the entire cerebrovasculature, leaving only 20 nm clefts between endfeet and blood vessels whereas forming small channels that allow the cerebrospinal fluid in the subarachnoid space to flow into the brain along the exterior of the entire blood circulatory pathway.…”

Section: Bbb Architecturementioning

confidence: 99%

“…26 An additional barrier is formed by astrocytic "endfoot" processes juxtaposed to the cerebrovasculature, permitting the bidirectional communication between neurons and astrocytes in addition to enabling astrocytes to communicate with the supplying circulations of the blood and cerebrospinal fluid. 26,27 Paravascular astrocytic processes sheath 97% of the entire cerebrovasculature, leaving only 20 nm clefts between endfeet and blood vessels whereas forming small channels that allow the cerebrospinal fluid in the subarachnoid space to flow into the brain along the exterior of the entire blood circulatory pathway. 25 Once cerebrospinal fluid enters paravascular spaces, the cerebrospinal fluid may selectively exchange its soluble contents with the interstitial fluid of the brain parenchyma.…”

Section: Bbb Architecturementioning

confidence: 99%

“…2,5,6 In addition, we recently conjugated the identical peptide to GNRs 2 to produce a photothermal ablation of β-amyloid. Two other groups conjugated fragments of the β-amyloid peptide (β-amyloid (31)(32)(33)(34)(35) and β-amyloid (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)) with AuNPs, resulting in the photothermal ablation of β-amyloid. 10 AuNPs have been used as adjuvants for therapeutic agents in spinal cord injuries in animal models.…”

Section: Introductionmentioning

confidence: 99%

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Peptides and proteins used to enhance gold nanoparticle delivery to the brain: preclinical approaches

Aguirre¹,

Morales²,

Gallardo-Toledo³

et al. 2015

IJN

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Artículo de publicación ISIAn exciting and emerging field in nanomedicine involves the use of gold nanoparticles (AuNPs) in the preclinical development of new strategies for the treatment and diagnosis of brain-related diseases such as neurodegeneration and cerebral tumors. The treatment of many brain-related disorders with AuNPs, which possess useful physical properties, is limited by the blood-brain barrier (BBB). The BBB highly regulates the substances that can permeate into the brain. Peptides and proteins may represent promising tools to improve the delivery of AuNPs to the central nervous system (CNS). In this review, we summarize the potential applications of AuNPs to CNS disorders, discuss different strategies based on the use of peptides or proteins to improve the delivery of AuNPs to the brain, and examine the intranasal administration route, which bypasses the BBB. We also analyze the potential neurotoxicity of AuNPs and the perspectives and new challenges concerning the use of peptides and proteins to enhance the delivery of AuNPs to the brain. The majority of the work described in this review is in a preclinical stage of experimentation, or in select cases, in clinical trials in humans. We note that the use of AuNPs still requires substantial study before being translated into human applications. However, for further clinical research, the issues related to the potential use of AuNPs must be analyzed.FONDECYT 11130494 1130425 FONDAP 15130011 UNAB DI569-14/R MECESUP UCH-081

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Physiological Roles of Aquaporin-4 in Brain

Cited by 594 publications

References 213 publications

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

Immunohistochemical localization of aquaporin 4 (AQP4) in the porcine gastrointestinal tract

Loss or Mislocalization of Aquaporin-4 Affects Diffusion Properties and Intermediary Metabolism in Gray Matter of Mice

Peptides and proteins used to enhance gold nanoparticle delivery to the brain: preclinical approaches

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