Crosstalk between autophagy and ferroptosis mediate injury in ischemic stroke by generating reactive oxygen species.

Stroke represents a significant threat to global human health, characterized by high rates of morbidity, disability, and mortality. Predominantly, strokes are ischemic in nature. Ischemic stroke (IS) is influenced by various cell death pathways, notably autophagy and ferroptosis. Recent studies have increasingly highlighted the interplay between autophagy and ferroptosis, a process likely driven by the accumulation of reactive oxygen species (ROS). Post-IS, either the inhibition of autophagy or its excessive activation can escalate ROS levels. Concurrently, the interaction between ROS and lipids during ferroptosis further augments ROS accumulation. Elevated ROS levels can provoke endoplasmic reticulum stress-induced autophagy and, in conjunction with free iron (Fe2+), can trigger ferroptosis. Moreover, ROS contribute to protein and lipid oxidation, endothelial dysfunction, and an inflammatory response, all of which mediate secondary brain injury following IS. This review succinctly explores the mechanisms of ROS-mediated crosstalk between autophagy and ferroptosis and the detrimental impact of increased ROS on IS. It also offers novel perspectives for IS treatment strategies.

Mechanisms of intermittent theta-burst stimulation attenuating nerve injury after ischemic reperfusion in rats through endoplasmic reticulum stress and ferroptosis.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) exerts neuroprotective effects early in cerebral ischemia/reperfusion (I/R) injury. Intermittent theta-brust stimulation (iTBS), a more time-efficient modality of rTMS, improves the efficiency without at least decreasing the efficacy of the therapy. iTBS elevates cortical excitability, and in recent years it has become increasingly common to apply iTBS to patients in the early post-IS period. However, little is known about the neuroprotective mechanisms of iTBS. Endoplasmic reticulum stress (ERS), and ferroptosis have been shown to be involved in the development of I/R injury. We aimed to investigate the potential regulatory mechanisms by which iTBS attenuates neurological injury after I/R in rats. METHODS: Rats were randomly divided into three groups: sham-operated group, MCAO/R group, and MCAO/R + iTBS group, and were stimulated with iTBS 36 h after undergoing middle cerebral artery occlusion (MCAO) or sham-operated. The expression of ERS, ferroptosis, and apoptosis-related markers was subsequently detected by western blot assays. We also investigated the mechanism by which iTBS attenuates nerve injury after ischemic reperfusion in rats by using the modified Neurological Severity Score (mNSS) and the balance beam test to measure nerve function. RESULTS: iTBS performed early in I/R injury attenuated the levels of ERS, ferroptosis, and apoptosis, and improved neurological function, including mNSS and balance beam experiments. It is suggested that this mode of stimulation reduces the cost per treatment by several times without compromising the efficacy of the treatment and could be a practical and less costly intervention.

Preconditioning exercise reduces brain damage of ischemic stroke in rats via PI3K-AKT pathway by bioinformatic analysis.

Ischemic stroke is one of the most vital causes of high neurological morbidity and mortality in the world. Preconditioning exercise is considered as the primary prevention of stroke to resistance to subsequent injury. We tried to research the underlying biological mechanisms of this exercise. Forty-two SD rats were randomly divided into three groups: middle cerebral artery occlusion (MCAO) group, exercise group with MCAO (EX + MCAO) group, and sham group, with 14 rats in each group. The EX + MCAO group underwent exercise preconditioning for 3 weeks before occlusion, and the other two groups were fed and exercised normally. After 3 weeks, MCAO model was made by thread plug method in the EX + MCAO group and MCAO group. After successful modeling, the Longa scale was used to evaluate the neurological impairment of rats at day 0, day 1, and day 2. The rats in each group were killed on the third day after modeling. TTC staining measured the infarct volume of each group. The morphology and apoptosis of cortical cells were observed by HE and Tunel staining. Three rats in each group underwent high-throughput sequencing. Bioinformatic analysis was used to find the deferentially expressed genes (DEGs) and predict the transcription factor binding sites (TFBS) of the next-generation sequencing results. Gene enrichment (GSEA) was used to analyze potential functional genes and their corresponding signaling pathways. The Longa scale showed EX + MCAO group had the neurological function better than the modeling group (P < 0.001). TTC staining showed that the infarct size of EX + MCAO group was less than MCAO group (P < 0.05). HE and Tunel staining showed that the cells in the EX + MCAO group and the sham group had normal morphology and fewer apoptotic cells than MCAO group. A new gene named 7994 was discovered and TFBS of this gene was predicted, which could interact with key genes such as Foxd3, Foxa2, NR4A2, SP1, CEBPA, and SOX10. GSEA showed that EX + MCAO group could promote and regulate angiogenesis and apoptosis through PI3K-AKT pathway. Preconditioning exercise could improve nerve function and reduce infarct size in rats. The underlying mechanism is to regulate the PI3K-AKT pathway through several key genes, promote cerebral angiogenesis, and reduce apoptosis.

Enriched environment treatment promotes neural functional recovery together with microglia polarization and remyelination after cerebral ischemia in rats.

BACKGROUND: Microglia activation and oligodendrocyte maturation are critical for remyelination after cerebral ischemia. Studies have shown that enriched environment (EE) can effectively alleviate stroke-induced neurological deficits. However, little is known about the mechanism associated with glial cells underlying the neuroprotection of EE. Therefore, this study focuses on investigating the effect of EE on activated microglia polarization as well as oligodendrogenesis in the progress of remyelination following cerebral ischemia. METHODS: The ischemia/reperfusion (I/R) injury model was established by middle cerebral artery occlusion (MCAO) in rats. Animals executed 4 weeks of environmental intervention after performing MCAO or sham surgery and were divided into sham, MCAO, and MCAO+EE groups. Cognitive function, myelin damage, microglia activation and polarization, inflammation, oligodendrogenesis, remyelination, and protein expression of the PI3K/AKT/GSK3ß signaling pathway were determined. RESULTS: The staining of NeuN indicated that the infarct size of MCAO rats was decreased under EE. EE intervention improved animal performance in the Morris water maze test and novel object recognition test, promoting the recovery of cognitive function after I/R injury. EE treatment alleviated myelin damage in MCAO rats, as evidenced by the lower fluorescence intensity ratio of SMI-32/MBP in MCAO+EE group. EE increased the fluorescence intensity ratio of NG2+/Ki67+/Olig2+, MBP, and MOG, enhancing the proliferation and differentiation of OPCs and oligodendrogenesis after MCAO. In terms of remyelination, more myelinated axons and lower G/ratio were detected in MCAO+EE rats compared with MCAO group. Moreover, EE treatment decreased the number of Iba1+/CD86+ M1 microglia, increased the number of Iba1+/CD206+ M2 microglia, and suppressed the inflammation response after I/R injury, which could be attributed to the augmented expression of PI3K/AKT/GSK3ß axis. CONCLUSION: EE improved long­term recovery of cognitive function after cerebral I/R injury, at least in part by promoting M2 microglia transformation through activation of the PI3K/AKT/GSK3ß signaling pathway, inhibiting inflammation to provide a favorable microenvironment for oligodendrocyte maturation and remyelination. The effect of the EE on myelin and inflammation could account for the neuroprotection provided by EE.

Enriched environment-induced neuroplasticity in ischemic stroke and its underlying mechanisms.

Stroke is a common cerebrovascular disease that can interrupt local blood flow in the brain, causing neuronal damage or even death, resulting in varying degrees of neurological dysfunction. Neuroplasticity is an important neurological function that helps neurons reorganize and regain function after injury. After cerebral ischemia, neuroplasticity changes are critical factors for restoring brain function. An enriched environment promotes increased neuroplasticity, thereby aiding stroke recovery. In this review, we discuss the positive effects of the enriched environment on neuroplasticity after cerebral ischemia, including synaptic plasticity, neurogenesis, and angiogenesis. In addition, we also introduce some studies on the clinical application of enriched environments in the rehabilitation of post-stroke patients, hoping that they can provide some inspiration for doctors and therapists looking for new approaches to stroke rehabilitation.

NPLC0393 from Gynostemma pentaphyllum ameliorates Alzheimer's disease-like pathology in mice by targeting protein phosphatase magnesium-dependent 1A phosphatase.

Alzheimer's disease (AD) is a neurodegenerative disease with clinical hallmarks of progressive cognitive impairment and memory loss. Gynostemma pentaphyllum ameliorates cognitive impairment, but the mechanisms remain obscure. Here, we determine the effect of triterpene saponin NPLC0393 from G. pentaphyllum on AD-like pathology in 3×Tg-AD mice and elucidate the underlying mechanisms. NPLC0393 was administered daily in vivo by intraperitoneal injection for 3 months and its amelioration on the cognitive impairment in 3×Tg-AD mice was assessed by new object recognition (NOR), Y-maze, Morris water maze (MWM), and elevated plus-maze (EPM) tests. The mechanisms were investigated by RT-PCR, western blot, and immunohistochemistry techniques, while verified by the 3×Tg-AD mice with protein phosphatase magnesium-dependent 1A (PPM1A) knockdown (KD) through brain-specific injection of adeno-associated virus (AAV)-ePHP-KD-PPM1A. NPLC0393 ameliorated AD-like pathology targeting PPM1A. It repressed microglial NLRP3 inflammasome activation by reducing NLRP3 transcription during priming and promoting PPM1A binding to NLRP3 to disrupt NLRP3 assembly with apoptosis-associated speck-like protein containing a CARD and pro-caspase-1. Moreover, NPLC0393 suppressed tauopathy by inhibiting tau hyperphosphorylation through PPM1A/NLRP3/tau axis and promoting microglial phagocytosis of tau oligomers through PPM1A/nuclear factor-κB/CX3CR1 pathway. PPM1A mediates microglia/neurons crosstalk in AD pathology, whose activation by NPLC0393 represents a promising therapeutic strategy for AD.

NLRP3 inflammasome activation after ischemic stroke.

Cerebral ischemia is a pathological condition resulting from the cessation or reduction of blood supply to the cerebral arteries. Neurological deficits that are clinically relevant can arise as a result of brain damage. The etiology of stroke is multifaceted and intricate, with the inflammatory response being a crucial component that warrants significant attention. Following a cerebrovascular accident, the levels of interleukin-1 beta and interleukin-18 within the central nervous system escalate due to the activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome. The inflammation is aggravated by the subsequent occurrence of pyroptosis. The mechanisms that activate the NLRP3 inflammasome pyroptosis signaling pathway axis are described in this article. In addition, we go over how pyroptosis interacts with other processes for regulated cell death. In addition, specific NLRP3 inflammasome pathway inhibitors are identified, which offer new approaches to preventing ischemic brain injury.

Pre-ischaemic Treatment with Enriched Environment Alleviates Acute Neuronal Injury by Inhibiting Endoplasmic Reticulum Stress-dependent Autophagy and Apoptosis.

Enriched environment (EE) is effective in preventing cerebral ischemia-reperfusion (I/R) injury. However, little is known about the mechanism underlying the neuroprotection of EE preprocessing. Endoplasmic reticulum (ER) stress has been demonstrated to be extensively involved in I/R injury. We aimed to investigate the potential regulatory mechanism of ER stress in the neuroprotection of pre-ischemic EE. Rats were subjected to middle cerebral artery occlusion (MCAO) or sham surgery after 4 weeks of exposure in standard or enriched environments. We found that EE pretreatment alleviates acute neuronal injury after MCAO, as shown by reduced infarct volume and neurological deficit score. The expression of ER stress-related proteins, markers of autophagy, and apoptosis were detected to investigate the underlying mechanism. Our results showed that pre-ischemic EE inhibited the ER stress, as evidenced by the inactivation of activating transcription factor 6 (ATF6), protein kinase RNA (PKR)-like ER kinase (PERK), and inositol-requiring enzyme 1 (IRE1) pathways. Moreover, the rats reared in EE were detected with lower autophagic activity and apoptosis levels. The decrease in activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), and phospho-c-Jun N-terminal kinases (p-JNK) expression suggested EE pretreatment might inhibit autophagy and apoptosis via modulating ER stress-mediated PERK-ATF4-CHOP and IRE1-JNK signal pathways, which provides a new idea for the prevention of the deleterious cerebral and functional consequences of ischemic stroke.

Pre exposure to enriched environment alleviates brain injury after ischemia-reperfusion by inhibiting p38MAPK/STAT1 pathway.

BACKGROUND: Stroke is one of the major diseases that endangers human health. It is widely reported that enriched environment (EE) can improve the neurological function in different brain injury models. Recently, relevant researches have indicated that MAPK pathway is closely related to the inflammatory response in nervous system related diseases. However, whether pre exposure to EE (EE pretreatment) has a preventive effect, and its mechanism are not clear. Therefore, this study aimed to determine the possible benefits and related mechanisms of EE in preventing brain injury after acute ischemia-reperfusion. METHODS: Adult Sprague Dawley rats were kept in enriched or standardized environments for 21 days. Then the middle cerebral artery of rats was occluded for one hour and 30 min, and then reperfusion was performed. Then their neurological deficit score was evaluated. Cerebral edema, along with ELISA and protein quantities of p38MAPK, JNK, ERK, IL-1ß, TNF-α, and co-localization of Iba1 were assessed. Changes in neuroinflammation and apoptosis were also detected in the penumbra cortex. RESULTS: Our research showed that EE pretreatment significantly alleviated acute cerebral ischemia-reperfusion injury in rats. Including the reduction of brain edema and apoptosis, and the improvement of neurological scores. In addition, the protein level of p38MAPK was significantly down regulated in EE pretreatment group, and the downstream protein STAT1 had the same trend. In addition, immunofluorescence results showed that Iba1 in EE pretreatment group decreased, the ELISA results showed that the classical proinflammatory cytokines increased significantly, while anti-inflammatory cytokines in EE pretreatment group increased, and the same results were obtained by Western blot analysis. CONCLUSION: On the whole, our research demonstrated that EE pretreatment can have a protective effect on the organism by inhibiting the p38 MAPK/STAT1 pathway. Thus, EE can be one of the most promising means of disease prevention. Secondly, p38MAPK/STAT1 pathway may be a latent target for the prevention of acute ischemic stroke.

Miltefosine as a PPM1A activator improves AD-like pathology in mice by alleviating tauopathy via microglia/neurons crosstalk.

Alzheimer's disease (AD) is a progressively neurodegenerative disease without effective treatment. Here, we reported that the levels of expression and enzymatic activity of phosphatase magnesium-dependent 1A (PPM1A) were both repressed in brains of AD patient postmortems and 3 × Tg-AD mice, and treatment of adeno-associated virus (AAV)-ePHP-overexpression (OE)-PPM1A for brain-specific PPM1A overexpression or the new discovered PPM1A activator Miltefosine (MF, FDA approved oral anti-leishmanial drug) for PPM1A enzymatic activation improved the AD-like pathology in 3 × Tg-AD mice. The mechanism was intensively investigated by assay against the 3 × Tg-AD mice with brain-specific PPM1A knockdown (KD) through AAV-ePHP-KD-PPM1A injection. MF alleviated neuronal tauopathy involving microglia/neurons crosstalk by both promoting microglial phagocytosis of tau oligomers via PPM1A/Nuclear factor-κb (NF-κB)/C-X3-C Motif Chemokine Receptor 1 (CX3CR1) signaling and inhibiting neuronal tau hyperphosphorylation via PPM1A/NLR Family Pyrin Domain Containing 3 (NLRP3)/tau axis. MF suppressed microglial NLRP3 inflammasome activation by both inhibiting NLRP3 transcription via PPM1A/NF-κB/NLRP3 pathway in priming step and promoting PPM1A binding to NLRP3 to interfere NLRP3 inflammasome assembly in assembly step. Our results have highly addressed that PPM1A activation shows promise as a therapeutic strategy for AD and highlighted the potential of MF in treating this disease.

The role of enriched environment in neural development and repair.

In addition to genetic information, environmental factors play an important role in the structure and function of nervous system and the occurrence and development of some nervous system diseases. Enriched environment (EE) can not only promote normal neural development through enhancing neuroplasticity but also play a nerve repair role in restoring functional activities during CNS injury by morphological and cellular and molecular adaptations in the brain. Different stages of development after birth respond to the environment to varying degrees. Therefore, we systematically review the pro-developmental and anti-stress value of EE during pregnancy, pre-weaning, and "adolescence" and analyze the difference in the effects of EE and its sub-components, especially with physical exercise. In our exploration of potential mechanisms that promote neurodevelopment, we have found that not all sub-components exert maximum value throughout the developmental phase, such as animals that do not respond to physical activity before weaning, and that EE is not superior to its sub-components in all respects. EE affects the developing and adult brain, resulting in some neuroplastic changes in the microscopic and macroscopic anatomy, finally contributing to enhanced learning and memory capacity. These positive promoting influences are particularly prominent regarding neural repair after neurobiological disorders. Taking cerebral ischemia as an example, we analyzed the molecular mediators of EE promoting repair from various dimensions. We found that EE does not always lead to positive effects on nerve repair, such as infarct size. In view of the classic issues such as standardization and relativity of EE have been thoroughly discussed, we finally focus on analyzing the essentiality of the time window of EE action and clinical translation in order to devote to the future research direction of EE and rapid and reasonable clinical application.

Diagnostic performance of miR-21, miR-124, miR-132, and miR-200b serums in post-stroke cognitive impairment patients.

INTRODUCTION: The diagnosis of post-stroke cognitive impairment (PSCI) mainly depends on neuro-psychological evaluation. It still lacks a sensitive and objective diagnostic biomarker. MicroRNAs (miRNAs, miRs) are novel and potential disease biomarkers. Our aim was to detect which specific miRNA is a good diagnostic biomarker for PSCI. MATERIAL AND METHODS: There were 77 first-ever stroke patients enrolled. Blood samples were collected at 14 days after stroke. Level of serum miR-21, miR-124, miR-132, and miR-200b were determined by quantitative polymerase chain reaction. Mini-mental state examination (MMSE) scale was used to measure the cognitive function of patients. Factional anisotropy (FA) score of diffusion tensor imaging was applied to detect the alteration of white matter. In addition, the relationship between miRNA level and cognitive status was further explored by correlation analysis. RESULTS: Finally, 45 PSCI and 32 post-stroke cognitive normality (PSCN) patients were enrolled. The expression of miR-21, miR-132, and miR-200b in PSCI patients was higher than in PSCN patients. In particular, the miR-21 level was substantially correlated with MMSE scores (r = 0.752, p < 0.001) and FA value (r = 0.636, p < 0.001). Additionally, the diagnostic performance of miR-21 alone or the combination of miR-21 and FA values performed well. CONCLUSIONS: The miR-21 alone or combination of miR-21 and FA values are valuable diagnostic biomarkers in discriminating PSCI from PSCN.

Enriched Environment Effects on Myelination of the Central Nervous System: Role of Glial Cells.

Myelination is regulated by various glial cells in the central nervous system (CNS), including oligodendrocytes (OLs), microglia, and astrocytes. Myelination of the CNS requires the generation of functionally mature OLs from OPCs. OLs are the myelin-forming cells in the CNS. Microglia play both beneficial and detrimental roles during myelin damage and repair. Astrocyte is responsible for myelin formation and regeneration by direct interaction with oligodendrocyte lineage cells. These glial cells are influenced by experience-dependent activities such as environmental enrichment (EE). To date, there are few studies that have investigated the association between EE and glial cells. EE with a complex combination of sensorimotor, cognitive, and social stimulation has a significant effect on cognitive impairment and brain plasticity. Hence, one mechanism through EE improving cognitive function may rely on the mutual effect of EE and glial cells. The purpose of this paper is to review recent research into the efficacy of EE for myelination and glial cells at cellular and molecular levels and offers critical insights for future research directions of EE and the treatment of EE in cognitive impairment disease.

Effects of enriched environment on microglia and functional white matter recovery in rats with post stroke cognitive impairment.

BACKGROUND: White matter damage is an important contributor to cognitive impairment after stroke. This study was designed to explore the beneficial effects of enriched environment (EE) on white matter recovery and cognitive dysfunction after stroke, and further explore the potential mechanism of EE on white matter recovery from the perspective of microglia and microglia-mediated neuroinflammation. METHODS: Male SD rats underwent middle cerebral artery occlusion (MCAO) or sham surgery. During the MCAO operation, a laser Doppler blood flow meter was used to monitor the blood flow to ensure the success of the model. At 72 h after the operation, 3 rats were selected for TTC staining to identify the infarct size. One week after surgery, the rats were randomly assigned into four different groups-MCAO+standard environment (SE), MCAO+enriched environment (EE), Sham+SE and Sham+EE for 4 weeks. At four weeks after MCAO surgery, neurological function deficiency condition and cognitive function were assessed using Longa score and Morris Water Maze prior to euthanasia. The loss or regeneration of myelin was stained with LFB, the expression of myelin regeneration-related protein and microglia protein was quantified by western blot and immunofluorescence, and the level of inflammatory factors was measured by ELISA. RESULTS: EE treatment remarkably decreased the neurological deficit score, ameliorated the cognitive functional deficit in MCAO rats. Furthermore, EE alleviated white matter lesions and demyelination, increased myelin basic protein expression and decreased the number of activated microglia in the hippocampus of MCAO rats. In addition, ELISA analysis indicated that EE decreased the level of IL-1ß, IL-6, which further suggests that EE may reduce the level of pro-inflammatory factors by affecting the expression of microglia marker, IBA1, provide a benefit physiological environment for myelin recovery, and improve post stroke cognitive impairment. CONCLUSIONS: Our results suggest that exposure to EE substantially reduced the damage to brain tissue caused by activation of microglia activation, decreased the level of pro-inflammatory cytokins, which may induced by microglia, protected and promote white matter recovery to improve cognitive function after stroke. Our findings also indicate exposure to EE is beneficial for patients with white matter impairment characterised by white matter disease-related inflammation.

Pre-ischemic exercise prevents inflammation and apoptosis by inhibiting MAPK pathway in ischemic stroke.

Introduction: Mitogen-activated protein kinase (MAPK) pathway is a major mechanism of acute brain damage in ischemic stroke. Pre-ischemic exercise is an effective method to reduce ischemic injury. However, the regulation by pre-ischemic exercise of MAPK pathway and associated mechanisms in animal models remains unclear. Materials and methods: In this study, Male SD rats were randomly divided into sham group, middle cerebral artery occlusion (MCAO) group, and exercise plus MCAO (EX + MCAO) group for 21 days, and then was established by MCAO. Longa score was used to measure neurological deficits at 0, 1, 2, and 3 days after MCAO. Hematoxylin and eosin staining was used to observe the brain injury. The expression of MAPK pathway was quantified by western blot. The M1 microglia protein was quantified by western blot and immunofluorescence, and the level of inflammatory factor was measured by enzyme-linked immunosorbent assay. TUNEL staining and western blot were used to measure apoptosis. Results: In the current study, we observed that pre-ischemic exercise effectively decreased infarct volume, neurological deficit score and brain injury in MCAO rats through suppressing the activation of p-JNK and p-ERK1/2. Further investigation revealed that pre-ischemic exercise decreased M1 microglia activation and the serum level of TNF-α and IL-1ß. In addition, the increased number of TUNEL-positive cells and Bax/Bcl-2 ratio also were reversed by pre-ischemic exercise. Conclusions: Pre-ischemic exercise can alleviate inflammatory response and apoptosis by inhibiting the MAPK pathway in MCAO rats.

Activation and Role of Astrocytes in Ischemic Stroke.

Ischemic stroke refers to the disorder of blood supply of local brain tissue caused by various reasons. It has high morbidity and mortality worldwide. Astrocytes are the most abundant glial cells in the central nervous system (CNS). They are responsible for the homeostasis, nutrition, and protection of the CNS and play an essential role in many nervous system diseases' physiological and pathological processes. After stroke injury, astrocytes are activated and play a protective role through the heterogeneous and gradual changes of their gene expression, morphology, proliferation, and function, that is, reactive astrocytes. However, the position of reactive astrocytes has always been a controversial topic. Many studies have shown that reactive astrocytes are a double-edged sword with both beneficial and harmful effects. It is worth noting that their different spatial and temporal expression determines astrocytes' various functions. Here, we comprehensively review the different roles and mechanisms of astrocytes after ischemic stroke. In addition, the intracellular mechanism of astrocyte activation has also been involved. More importantly, due to the complex cascade reaction and action mechanism after ischemic stroke, the role of astrocytes is still difficult to define. Still, there is no doubt that astrocytes are one of the critical factors mediating the deterioration or improvement of ischemic stroke.

Mechanism of Endoplasmic Reticulum Stress in Cerebral Ischemia.

Endoplasmic reticulum (ER) is the main organelle for protein synthesis, trafficking and maintaining intracellular Ca2+ homeostasis. The stress response of ER results from the disruption of ER homeostasis in neurological disorders. Among these disorders, cerebral ischemia is a prevalent reason of death and disability in the world. ER stress stemed from ischemic injury initiates unfolded protein response (UPR) regarded as a protection mechanism. Important, disruption of Ca2+ homeostasis resulted from cytosolic Ca2+ overload and depletion of Ca2+ in the lumen of the ER could be a trigger of ER stress and the misfolded protein synthesis. Brain cells including neurons, glial cells and endothelial cells are involved in the complex pathophysiology of ischemic stroke. This is generally important for protein underfolding, but even more for cytosolic Ca2+ overload. Mild ER stress promotes cells to break away from danger signals and enter the adaptive procedure with the activation of pro-survival mechanism to rescue ischemic injury, while chronic ER stress generally serves as a detrimental role on nerve cells via triggering diverse pro-apoptotic mechanism. What's more, the determination of some proteins in UPR during cerebral ischemia to cell fate may have two diametrically opposed results which involves in a specialized set of inflammatory and apoptotic signaling pathways. A reasonable understanding and exploration of the underlying molecular mechanism related to ER stress and cerebral ischemia is a prerequisite for a major breakthrough in stroke treatment in the future. This review focuses on recent findings of the ER stress as well as the progress research of mechanism in ischemic stroke prognosis provide a new treatment idea for recovery of cerebral ischemia.

Therapeutic Potential of Cytokines in Demyelinating Lesions After Stroke.

White matter damage is a component of most human stroke and usually accounts for at least half of the lesion volume. Subcortical white matter stroke (WMS) accounts for 25% of all strokes and causes severe motor and cognitive dysfunction. The adult brain has a very limited ability to repair white matter damage. Pathological analysis shows that demyelination or myelin loss is the main feature of white matter injury and plays an important role in long-term sensorimotor and cognitive dysfunction. This suggests that demyelination is a major therapeutic target for ischemic stroke injury. An acute inflammatory reaction is triggered by brain ischemia, which is accompanied by cytokine production. The production of cytokines is an important factor affecting demyelination and myelin regeneration. Different cytokines have different effects on myelin damage and myelin regeneration. Exploring the role of cytokines in demyelination and remyelination after stroke and the underlying molecular mechanisms of demyelination and myelin regeneration after ischemic injury is very important for the development of rehabilitation treatment strategies. This review focuses on recent findings on the effects of cytokines on myelin damage and remyelination as well as the progress of research on the role of cytokines in ischemic stroke prognosis to provide a new treatment approach for amelioration of white matter damage after stroke.

Effectiveness and mechanisms of enriched environment in post-stroke cognitive impairment.

Post-stroke cognitive impairment (PSCI) is one of the most common complications of stroke, it is also an important reason for the poor prognosis in stroke patients with motor and speech dysfunction. Enriched Environment (EE), a novel and easy-to-implement rehabilitation treatment strategy, is thought to be a potential intervention for PSCI recently. In this paper, we review the therapeutic effects and related mechanisms of EE in PSCI from the level of animal research and clinical application. Besides, we further discuss the application prospects and limitations of EE in PSCI patients.

Neuroprotective effects of bone marrow stromal cells on rat organotypic hippocampal slice culture model of cerebral ischemia.

Organotypic hippocampal slice cultures prepared from newborn rats were maintained in vitro for 9 days. Cultures were then exposed to 30 min of combined oxygen-glucose deprivation (OGD). After OGD, the area covered by neurites was decreased. The dead cells of hippocampal slices in the ischemia group were 40.4% at day 3 and 41.6% at day 7 after OGD. The ultrastructure of the CA1 region of the slices was seriously damaged. While hippocampal slices were cultured in combination with bone marrow stromal cells (MSCs), the average area covered by neurites was comparatively increased. The dead cells were only 25.2% at day 3 and 27.1% at day 7 after coculture. The damage of the ultrastructure of the CA1 region in the coculture group was reduced significantly. Thus, in an in vitro model of simulated ischemia, MSCs can promote the outgrowth of neurites from hippocampal slices and alleviate cell damage. The neuroprotective effect might be mediated through diffusible neurotrophic factors secreted from MSCs.