Astrocytes ; metabolism ; pathology ; Epilepsy ; pathology ; Humans

Astrocytes are the most abundant cells in the central nervous system and play significant roles in normal brain. With cerebral infarction, astrocytes are activated as reactive astrocytes and form glial scars, which play an essential part in brain injury. According to their roles in neuroprotection after cerebral infarction, regulation of scar formation, nerve regeneration, maintenance of blood-brain barrier, promotion of angiogenesis and immune response, scholars have proposed a variety of therapeutic strategies based on targeting astrocytes. This article reviews the research progress on the changes in astrocyte signaling pathways before and after cerebral infarction and the related therapeutic strategies.
Astrocytes ; Cerebral Infarction ; physiopathology ; therapy ; Humans ; Neuroglia ; pathology ; Signal Transduction

When ischemia or hemorrhagic stroke occurs, astrocytes are activated by a variety of endogenous regulatory factors to become reactive astrocytes. Subsequently, reactive astrocytes proliferate, differentiate, and migrate around the lesion to form glial scar with the participation of microglia, neuron-glial antigen 2(NG2) glial cells, and extracellular matrix. The role of glial scars at different stages of stroke injury is different. At the middle and late stages of the injury, the secreted chondroitin sulfate proteoglycan and chondroitin sulfate are the main blockers of axon regeneration and nerve function recovery. Targeted regulation of glial scars is an important pathway for neurological rehabilitation after stroke. Chinese medicine has been verified to be effective in stroke rehabilitation in clinical practice, possibly because it has the functions of promoting blood resupply, anti-inflammation, anti-oxidative stress, inhibiting cell proliferation and differentiation, and benign intervention in glial scars. This study reviewed the pathological process and signaling mechanisms of glial scarring after stroke, as well as the intervention of traditional Chinese medicine upon glial scar, aiming to provide theoretical reference and research evidence for developing Chinese medicine against stroke in view of targeting glial scarring.
Astrocytes ; Axons/pathology* ; Cicatrix/pathology* ; Gliosis/pathology* ; Humans ; Medicine, Chinese Traditional ; Nerve Regeneration ; Stroke/drug therapy*

Chronic pain is challenging to treat due to the limited therapeutic options and adverse side-effects of therapies. Astrocytes are the most abundant glial cells in the central nervous system and play important roles in different pathological conditions, including chronic pain. Astrocytes regulate nociceptive synaptic transmission and network function via neuron-glia and glia-glia interactions to exaggerate pain signals under chronic pain conditions. It is also becoming clear that astrocytes play active roles in brain regions important for the emotional and memory-related aspects of chronic pain. Therefore, this review presents our current understanding of the roles of astrocytes in chronic pain, how they regulate nociceptive responses, and their cellular and molecular mechanisms of action.
Humans ; Astrocytes/pathology* ; Chronic Pain/pathology* ; Neuroglia/physiology* ; Neurons/physiology* ; Synaptic Transmission ; Chronic Disease

AIM AND METHODSThe relation between AT sclerosis (loss of neurons and proliferation of astrocytes) and long-lasting epileptic susceptibility was investigated by thionine staining, GFAP immunohistochemistry and observing the behavior of rats, after scorpion venom (SV) or normal saline (NS) administrated for three week.

RESULTSCompared with NS+ NS group, both the loss of neurons and proliferation of astrocytes were very marked in KA+ NS group (epileptic susceptible rats) (P < 0.05), but those changes were not visible in KA+ NS group (epileptic nonsusceptible rats).

CONCLUSIONSIt suggested that AT sclerosis may be one of important reasons of the long-lasting epileptic susceptibility.

Animals ; Astrocytes ; pathology ; Epilepsy ; pathology ; Glial Fibrillary Acidic Protein ; metabolism ; Male ; Neurons ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

Nerve regeneration in adult mammalian spinal cord is poor because of the lack of intrinsic regeneration of neurons and extrinsic factors - the glial scar is triggered by injury and inhibits or promotes regeneration. Recent technological advances in spatial transcriptomics (ST) provide a unique opportunity to decipher most genes systematically throughout scar formation, which remains poorly understood. Here, we first constructed the tissue-wide gene expression patterns of mouse spinal cords over the course of scar formation using ST after spinal cord injury from 32 samples. Locally, we profiled gene expression gradients from the leading edge to the core of the scar areas to further understand the scar microenvironment, such as neurotransmitter disorders, activation of the pro-inflammatory response, neurotoxic saturated lipids, angiogenesis, obstructed axon extension, and extracellular structure re-organization. In addition, we described 21 cell transcriptional states during scar formation and delineated the origins, functional diversity, and possible trajectories of subpopulations of fibroblasts, glia, and immune cells. Specifically, we found some regulators in special cell types, such as Thbs1 and Col1a2 in macrophages, CD36 and Postn in fibroblasts, Plxnb2 and Nxpe3 in microglia, Clu in astrocytes, and CD74 in oligodendrocytes. Furthermore, salvianolic acid B, a blood-brain barrier permeation and CD36 inhibitor, was administered after surgery and found to remedy fibrosis. Subsequently, we described the extent of the scar boundary and profiled the bidirectional ligand-receptor interactions at the neighboring cluster boundary, contributing to maintain scar architecture during gliosis and fibrosis, and found that GPR37L1_PSAP, and GPR37_PSAP were the most significant gene-pairs among microglia, fibroblasts, and astrocytes. Last, we quantified the fraction of scar-resident cells and proposed four possible phases of scar formation: macrophage infiltration, proliferation and differentiation of scar-resident cells, scar emergence, and scar stationary. Together, these profiles delineated the spatial heterogeneity of the scar, confirmed the previous concepts about scar architecture, provided some new clues for scar formation, and served as a valuable resource for the treatment of central nervous system injury.
Mice ; Animals ; Gliosis/pathology* ; Cicatrix/pathology* ; Spinal Cord Injuries ; Astrocytes/metabolism* ; Spinal Cord/pathology* ; Fibrosis ; Mammals ; Receptors, G-Protein-Coupled

OBJECTIVETo study pathologic features of glial cells in progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) and to explore their pathologic significance.

METHODSBrain tissues from 2 cases with PSP and 3 cases with CBD, all confirmed by autopsies, were examined by routine neuropathologic methods, Gallyas-Braak staining and tau immunostaining. Brain tissues from 6 Alzheimer's disease cases, 4 cases with Parkinson's disease and 6 elderly with no neurologic abnormality were used as controls.

RESULTSGallyas-Braak staining demonstrated tuft-shaped astrocytes and coiled-body oligodendroglial cells in the brain tissues of 2 cases with PSP and 3 cases with CBD. The tuft-shaped astrocytes appeared prominently in the frontal and parietal cortex, basal ganglia and grey matter of the brainstem. The coiled-body oligodendroglial cells were distributed widely in the white matter of the frontal and parietal lobes, basal ganglia, brainstem and cerebellum. However, astrocytic plaques, composed of degenerative stubby processes with radiating arrangement, only appeared in the frontal, parietal and cingular cortex, as well as in the striatum of 3 cases with CBD. The astrocytic plaques and tuft-shaped astrocytes coexisted in the same areas, including parietal and cingular cortex and striatum, in CBD. All these glial abnormalities showed tau-positive immunoreaction not found in control cases.

CONCLUSIONSThe tuft-shaped astrocytes and coiled-body oligodendroglial cells are common glial morphologic features of both PSP and CBD. Astrocytic plaques are also characteristically seen in CBD.

Aged ; Aged, 80 and over ; Astrocytes ; pathology ; Basal Ganglia ; pathology ; Brain Stem ; pathology ; Cerebral Cortex ; pathology ; Humans ; Male ; Neurodegenerative Diseases ; pathology ; Oligodendroglia ; pathology ; Supranuclear Palsy, Progressive ; pathology

OBJECTIVETo investigate the effects of inhibiting gap junctional intercellular communication on hypoxia/reoxygenation injury in astrocytes.

METHODSPrimary cultured cerebral cortical astrocytes of neonate rats were divided into normal control group, hypoxia reoxygenation injury group and 18-α-glycyrrhetinic acid and oleamide (gap junctional intercellular channel inhibitors) group. The gap junction intercellular communication was determined by Parachute assay. The viability of astrocyes was detected by MTT assay. The apoptosis of astrocytes were detected with annexin V/PI and Hoechst 33258 staining.

RESULTSCompared with the normal control group, the gap junctional function of astrocytes was increased significantly in ischemia/reperfusion group (P<0.01), the surviving fraction of astrocytes decreased significantly (P<0.01) and its cell apoptosis ratio increased significantly (P<0.01). Compared with the ischemia/reperfusion group, the gap junctional function of astrocytes in18-α-glycyrrhetinic acid and oleamide group decreased significantly (P<0.01), the viability of astrocytes increased significantly (P<0.01), while cell apoptosis decreased significantly (P<0.01).

CONCLUSIONInhibition of intercellular gap junction has protective effect against hypoxia/reoxygenation injury in astrocytes.

Animals ; Apoptosis ; Astrocytes ; cytology ; pathology ; Cell Communication ; Cell Hypoxia ; Cells, Cultured ; Gap Junctions ; Oxygen ; Rats

Mood disorder is a common psychiatric illness with a high lifetime prevalence in the general population. A serious problem such as suicide is commonly occurring in the patients with depression. Till now, the monoamine hypothesis has been the most popular theory of pathogenesis for depression. However, the more specific pathophysiology of depression and cellular molecular mechanism underlying action of commercial antidepressants have not been clearly defined. Several recent studies demonstrated that glial cells, especially astrocytes, are a promising answer to the pathophysiology of depression. In this article, current understanding of biology and molecular mechanisms of glial cells in the pathology of mood disorder and new research on the pathophysiology of depression will be discussed.
Antidepressive Agents ; Astrocytes ; Biology ; Depression ; Humans ; Mood Disorders* ; Neuroglia* ; Pathology ; Prevalence ; Suicide

Epilepsy is a brain condition characterized by the recurrence of unprovoked seizures. Recent studies have shown that complement component 3 (C3) aggravate the neuronal injury in epilepsy. And our previous studies revealed that TRPV1 (transient receptor potential vanilloid type 1) is involved in epilepsy. Whether complement C3 regulation of neuronal injury is related to the activation of TRPV1 during epilepsy is not fully understood. We found that in a mouse model of status epilepticus (SE), complement C3 derived from astrocytes was increased and aggravated neuronal injury, and that TRPV1-knockout rescued neurons from the injury induced by complement C3. Circular RNAs are abundant in the brain, and the reduction of circRad52 caused by complement C3 promoted the expression of TRPV1 and exacerbated neuronal injury. Mechanistically, disorders of neuron-glia interaction mediated by the C3-TRPV1 signaling pathway may be important for the induction of neuronal injury. This study provides support for the hypothesis that the C3-TRPV1 pathway is involved in the prevention and treatment of neuronal injury and cognitive disorders.
Animals ; Astrocytes/metabolism* ; Complement C3/metabolism* ; Epilepsy ; Mice ; Neurons/pathology* ; Status Epilepticus ; TRPV Cation Channels/metabolism*