Glial Activation, A Common Mechanism Underlying Spinal Synaptic Plasticity？

Long-term potentiation(LTP)at synapses between primary afferents and spinal dorsal horn neurons induced by noxious electrical stimulation or injury of peripheral nerve is considered to underlie chronic pain[1].The mechanisms of the spinal LTP have been intensively investigated,since it was discovered in 1995[2].In recent years,spinal application

Connecting cellular mechanisms and extracellular vesicle cargo in traumatic brain injury

Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.

β2-Microglobulin exacerbates neuroinflammation,brain damage,and cognitive impairment after stroke in rats

β2-Microglobulin(β2M),a component of the major histocompatibility complex class I molecule,is associated with aging-related cognitive impairment and Alzheimer’s disease.Although upregulation ofβ2M is considered to be highly related to ischemic stroke,the specific role and underlying mechanistic action ofβ2M are poorly understood.In this study,we established a rat model of focal cerebral ischemia by occlusion of the middle cerebral artery.We found thatβ2M levels in the cerebral spinal fluid,serum,and brain tissue were significantly increased in the acute period but gradually decreased during the recovery period.RNA interference was used to inhibitβ2M expression in the acute period of cerebral stroke.Tissue staining with 2,3,5-triphenyltetrazolium chloride and evaluation of cognitive function using the Morris water maze test demonstrated that decreasedβ2M expression in the ischemic penumbra reduced infarct volume and alleviated cognitive deficits,respectively.Notably,glial cell,caspase-1(p20),and Nod-like receptor pyrin domain containing 3(NLRP3)inflammasome activation as well as production of the inflammatory cytokines interleukin-1β,interleukin-6,and tumor necrosis factor-αwere also effectively inhibited byβ2M silencing.These findings suggest thatβ2M participates in brain injury and cognitive impairment in a rat model of ischemic stroke through activation of neuroinflammation associated with the NLRP3 inflammasome.

Imaging and Spectral Characteristics of Amyloid Plaque Autofluorescence in Brain Slices from the APP/PS1 Mouse Model of Alzheimer’s Disease

Amyloid deposits are one of the hallmark pathological lesions of Alzheimer's disease(AD). They can be visualized by thioflavin-S, silver impregnation,Congo red staining, and immunohistochemical reactions.However, that amyloid deposits generate blue autofluorescence(auto-F) has been ignored. Here, we report that visible light-induced auto-F of senile plaques(SPs) was detected and validated with conventional methods. Brain slices from APP/PS1(amyloid precursor protein/presenilin1) transgenic mice were mounted on slides, rinsed,coverslipped and observed for details of the imaging and spectral characteristics of the auto-F of SPs. Then the slices were treated with the above classic methods for comparative validation. We found that the SP auto-F was greatest under blue-violet excitation with a specific emission spectrum, and was much easier, more sensitive, and reliable than the classic methods. Because it does not damage slices, observation of auto-F can be combined with all post-staining techniques in slices and for brain-wide imaging in AD.