Sensing and Regulating Synaptic Activity by Astrocytes at Tripartite Synapse

AbstractBrain photobiomodulation (PBM) is an innovative treatment for a variety of neurological conditions, including cerebral ischemia. However, the capability of PBM for ischemic stroke needs to be further explored and its mechanisms of action remain currently unclear. The aim of the present research was to identify a treatment protocol capable of inducing neuroprotection and to investigate the molecular mechanisms activated by a dual-wavelength near infrared (NIR) laser source in an organotypic hippocampal slice model of hypoxia/ischemia. Hippocampal slices were exposed to oxygen and glucose deprivation (OGD) for 30 min followed by NIR laser light (fluence 3.71, 7.42, or 14.84 J/cm2; wavelengths 808 nm and 905 nm) delivered immediately or 30 min or 60 min after OGD, in order to establish a therapeutic window. Neuronal injury was assessed by propidium iodide fluorescence 24 h later. Our results show that NIR laser irradiation attenuates OGD neurotoxicity once applied immediately or 30 min after OGD. Western blot analysis of proteins involved in neuroinflammation (iNOS, COX-2, NFkB subunit p65, and Bcl-2) and in glutamatergic-mediated synaptic activity (vGluT1, EAAT2, GluN1, and PSD95) showed that the protein modifications induced by OGD were reverted by NIR laser application. Moreover, CA1 confocal microscopy revealed that the profound morphological changes induced by OGD were reverted by NIR laser radiation. In conclusion, NIR laser radiation attenuates OGD neurotoxicity in organotypic hippocampal slices through attenuation of inflammatory mechanisms. These findings shed light on molecular definition of NIR neuroprotective mechanisms, thus underlining the potential benefit of this technique for the treatment of cerebral ischemia.

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Neuro-Inspired Signal Processing in Ferromagnetic Nanofibers

Biomimetics ◽

10.3390/biomimetics6020032 ◽

2021 ◽

Vol 6 (2) ◽

pp. 32

Author(s):

Tomasz Blachowicz ◽

Jacek Grzybowski ◽

Pawel Steblinski ◽

Andrea Ehrmann

Keyword(s):

Data Processing ◽

Data Storage ◽

Domain Walls ◽

Data Transfer ◽

Synaptic Activity ◽

Neuromorphic Computing ◽

Rotating Magnetic Fields ◽

Micromagnetic Simulations ◽

Energy Consuming ◽

Stochastic Data

Computers nowadays have different components for data storage and data processing, making data transfer between these units a bottleneck for computing speed. Therefore, so-called cognitive (or neuromorphic) computing approaches try combining both these tasks, as is done in the human brain, to make computing faster and less energy-consuming. One possible method to prepare new hardware solutions for neuromorphic computing is given by nanofiber networks as they can be prepared by diverse methods, from lithography to electrospinning. Here, we show results of micromagnetic simulations of three coupled semicircle fibers in which domain walls are excited by rotating magnetic fields (inputs), leading to different output signals that can be used for stochastic data processing, mimicking biological synaptic activity and thus being suitable as artificial synapses in artificial neural networks.

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Carotenoids in the Management of Glaucoma: A Systematic Review of the Evidence

Nutrients ◽

10.3390/nu13061949 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1949

Author(s):

Drake W. Lem ◽

Dennis L. Gierhart ◽

Pinakin Gunvant Davey

Keyword(s):

Systematic Review ◽

Tissue Injury ◽

Open Angle Glaucoma ◽

Synaptic Activity ◽

Antioxidant Defenses ◽

Cochrane Library ◽

Retinal Ganglion ◽

Age Related ◽

Retinal Ganglion Cell Survival ◽

Oxidative Insult

Primary open-angle glaucoma (POAG) remains a leading cause of irreversible blindness globally. Recent evidence further substantiates sustained oxidative stress, and compromised antioxidant defenses are key drivers in the onset of glaucomatous neurodegeneration. Overwhelming oxidative injury is likely attributed to compounding mitochondrial dysfunction that worsens with age-related processes, causing aberrant formation of free radical species. Thus, a compromised systemic antioxidant capacity exacerbates further oxidative insult in glaucoma, leading to apoptosis, neuroinflammation, and subsequent tissue injury. The purpose of this systematic review is to investigate the neuroprotective benefits of the macular carotenoids lutein, zeaxanthin, and meso-zeaxanthin on glaucomatous neurodegeneration for the purpose of adjunctive nutraceutical treatment in glaucoma. A comprehensive literature search was conducted in three databases (PubMed, Cochrane Library, and Web of Science) and 20 records were identified for screening. Lutein demonstrated enhanced neuroprotection on retinal ganglion cell survival and preserved synaptic activity. In clinical studies, a protective trend was seen with greater dietary consumption of carotenoids and risk of glaucoma, while greater carotenoid levels in macular pigment were largely associated with improved visual performance in glaucomatous eyes. The data suggest that carotenoid vitamin therapy exerts synergic neuroprotective benefits and has the capacity to serve adjunctive therapy in the management of glaucoma.

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