Mitochondria in Ischemic Stroke: New Insight and Implications

Prenatal electronic cigarette exposure decreases brain glucose utilization and worsens outcome in offspring hypoxic-ischemic brain injury

It has been shown that prenatal nicotine and tobacco smoke exposure can cause different neurobehavioral disorders in the offspring. We hypothesize that prenatal exposure to nicotine-containing electronic cigarette (e-Cig) vapor can predispose newborn to enhanced sensitivity to hypoxic-ischemic (HI) brain injury and impaired motor and cognitive functions. In this study, pregnant CD1 mice were exposed to e-Cig vapor (2.4% nicotine). Primary cortical neurons isolated from e-Cig exposed fetus were exposed to oxygen-glucose deprivation followed by reoxygenation (OGD/R) to mimic HI brain injury. Cell viability and glucose utilization were analyzed in these neurons. HI brain injury was induced in 8-9-day-old pups. Short-term brain injury was evaluated by triphenyltetrazolium chloride staining. Long-term motor and cognitive functions were evaluated by open field, novel object recognition, Morris water maze, and foot fault tests. Western blotting and immunofluorescence were done to characterize glucose transporters in offspring brain. We found that e-Cig exposed neurons demonstrated decreased cell viability and glucose utilization in OGD/R. Prenatally e-Cig exposed pups also had increased brain injury and edema 24 hr after HI brain injury. Further, in utero e-Cig exposed offspring with HI brain injury displayed impaired memory, learning, and motor coordination at adolescence. Additionally, the expression of glucose transporters decreased in e-Cig exposed offspring brain after HI brain injury. These results indicate that reduced glucose utilization can contribute to prenatal e-Cig exposure induced worsened HI brain injury in offspring. This study is instrumental in elucidating the possible deleterious effects of e-Cig use in the general population.

Extracellular Mitochondrial Dysfunction in Cerebrospinal Fluid of Patients with Delayed Cerebral Ischemia after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Mitochondrial dysfunction is related to brain ischemic injury and neural cell death. However, little is known about the association between mitochondrial dysfunction of cerebrospinal fluid (CSF) and delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH). The objective of this study was to investigate whether extracellular CSF mitochondria might serve as a potential biomarker for DCI.

METHODS

CSF samples were serially collected at 1, 3, and 5 days following SAH in 33 patients (DCI, n = 12; and non-DCI, n = 21) who underwent coil embolization. To monitor mitochondrial membrane potentials, JC-1 dye was used. The ratio (red/green) of JC-1 was considered as an indicator of intact mitochondrial membrane potential. Flow cytometry was done to analyze extracellular mitochondria particles and their possible cellular origins.

RESULTS

DCI patients had lower JC-1 red/green ratios than non-DCI patients at 1 day (3.35 [3.20-3.75] vs. 3.70 [3.40-3.95] in non-DCI) and 3 days (4.65 [4.45-5.00] vs. 5.10 [4.65-5.30] in non-DCI) after SAH. At 5 days after SAH, JC-1 red/green ratio was significantly lower in DCI than that in non-DCI (3.05 [2.90-3.35] vs. 4.20 [4.10-4.50]; p < 0.01) patients. DCI patients had a higher percentage of vWF-positive mitochondria (40.10% [38.25%-44.90%] vs. 30.20% [25.70%-36.68%]) and a lower percentage of GLAST-positive mitochondria particles (26.85% [17.10%-30.00%] vs. 31.60% [26.70%-35.00%]) than non-DCI patients. However, there was no significant difference in CD45-positive (p = 0.369) or CD41/61-positive mitochondrial particles (p = 0.155) between the two groups of patients.

CONCLUSIONS

Mitochondrial membrane potential could be a marker of DCI. JC-1 ratios seemed to be able to predict future DCI onset. Further studies are needed to determine detailed mechanisms of extracellular mitochondria-mediated cell-to-cell signals in DCI.

Selective brain hypothermia-induced neuroprotection against focal cerebral ischemia/reperfusion injury is associated with Fis1 inhibition

Selective brain hypothermia is considered an effective treatment for neuronal injury after stroke, and avoids the complications of general hypothermia. However, the mechanisms by which selective brain hypothermia affects mitochondrial fission remain unknown. In this study, we investigated the effect of selective brain hypothermia on the expression of fission 1 (Fis1) protein, a key factor in the mitochondrial fission system, during focal cerebral ischemia/reperfusion injury. Sprague-Dawley rats were divided into four groups. In the sham group, the carotid arteries were exposed only. In the other three groups, middle cerebral artery occlusion was performed using the intraluminal filament technique. After 2 hours of occlusion, the filament was slowly removed to allow blood reperfusion in the ischemia/reperfusion group. Saline, at 4°C and 37°C, were perfused through the carotid artery in the hypothermia and normothermia groups, respectively, followed by restoration of blood flow. Neurological function was assessed with the Zea Longa 5-point scoring method. Cerebral infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride staining, and apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining. Fis1 and cytosolic cytochrome c levels were assessed by western blot assay. Fis1 mRNA expression was assessed by quantitative reverse transcription-polymerase chain reaction. Mitochondrial ultrastructure was evaluated by transmission electron microscopy. Compared with the sham group, apoptosis, Fis1 protein and mRNA expression and cytosolic cytochrome c levels in the cortical ischemic penumbra and cerebral infarct volume were increased after reperfusion in the other three groups. These changes caused by cerebral ischemia/reperfusion were inhibited in the hypothermia group compared with the normothermia group. These findings show that selective brain hypothermia inhibits Fis1 expression and reduces apoptosis, thereby ameliorating focal cerebral ischemia/reperfusion injury in rats. Experiments were authorized by the Ethics Committee of Qingdao Municipal Hospital of China (approval No. 2019008).

Mitochondria as a therapeutic target for ischemic stroke

Stroke is the leading cause of death and physical disability worldwide. Mitochondrial dysfunction has been considered as one of the hallmarks of ischemic stroke and contributes to the pathology of ischemia and reperfusion. Mitochondria is essential in promoting neural survival and neurological improvement following ischemic stroke. Therefore, mitochondria represent an important drug target for stroke treatment. This review discusses the mitochondrial molecular mechanisms underlying cerebral ischemia and involved in reactive oxygen species generation, mitochondrial electron transport dysfunction, mitochondria-mediated regulation of inflammasome activation, mitochondrial dynamics and biogenesis, and apoptotic cell death. We highlight the potential of mitochondrial transfer by stem cells as a therapeutic target for stroke treatment and provide valuable insights for clinical strategies. A better understanding of the roles of mitochondria in ischemia-induced cell death and protection may provide a rationale design of novel therapeutic interventions in the ischemic stroke.

Exercise Training Enhances Platelet Mitochondrial Bioenergetics in Stroke Patients: A Randomized Controlled Trial

Exercise training (ET) may impact physical fitness by affecting mitochondrial functions. This study aimed to elucidate the effect of ET on aerobic capacity and platelet mitochondrial bioenergetics (MTB) in stroke patients. Among the 30 stroke patients who underwent the traditional rehabilitation program (TRP), 15 were randomly assigned to have ET (50-60% VO_2peak for 30 min/day, 5 days/week for 4 weeks), and those remaining received only the TRP (control group). The peak exercise capacity (VO_2peak) and platelet MTB, including oxidative phosphorylation (OXPHOS) and the electron transport chain (ETC), were measured through automatic gas analysis and high-resolution respirometry, respectively. The results demonstrated that ET significantly increased the VO_2peak (17.7%) and O₂ uptake efficiency slope (31.9%) but decreased the ventilation versus CO₂ production slope (-7.65%). Patients who underwent ET also had significantly enhanced platelet mitochondrial OXPHOS and ETC by activating the FADH2 (Complex II)-dependent pathway, but depressed plasma myeloperoxidase (-28.4%) and interleukin-6 levels (-29.9%). Moreover, changes in VO_2peak levels were positively correlated with changes in platelet OXPHOS and ETC capacities. In conclusion, ET increases the platelet MTB by enhancing Complex II activity in stroke patients. The exercise regimen also enhances aerobic fitness and depresses oxidative stress/pro-inflammatory status in stroke patients.

Transplantation of viable mitochondria attenuates neurologic injury after spinal cord ischemia

OBJECTIVES

Spinal cord ischemia (SCI) is one of the major concerns of postoperative paraplegia during major vascular or aortic surgery. Since mitochondrial dysfunction develops at the early stage of SCI, this study tested the neuronal protective effect of transplantation of viable mitochondria to the ischemic cord in rats.

METHODS

SCI was induced by crossclamping of thoracic aorta at T6 level for 25 minutes, followed by release of vascular clip to restore aortic blood flow in the anesthetized rats. Mitochondria (100 μg) were isolated from freshly harvested soleus muscle and delivered via the internal jugular vein before releasing of vascular clip. The motor function was assessed independently up to 7 days after reperfusion. Spinal cords were harvested and analyzed for molecular and histological changes.

RESULTS

Whole-body in vivo images acquired by an in vivo imaging system confirmed the enhancement of MitoTracker fluorescence at the regions below crossclamping and in the ischemic cord. Compared with control vehicles, transplantation of mitochondria significantly improved the lower-limb locomotor function of rats subjected to cord ischemia up to 7 days after surgery. Mitochondrial transplantation suppressed the regional endoplasmic reticulum stress in the ischemic cord by attenuating CCAAT-enhancer-binding protein homologous protein expression and restoring binding immunoglobulin protein levels. In accordance, tissue levels of interleukin-6, tumor necrosis factor-α, and caspase-3 were attenuated in the mitochondrial transplanted group. Histologic examination also showed significant increase in numbers of Nissls bodies in the neurons at the ventral horn of ischemic cord following mitochondrial transplantation.

CONCLUSIONS

Our study showed that transplantation of freshly isolated mitochondria during the early stage of spinal cord ischemia-reperfusion injury suppressed the oxidative stress in endoplasmic reticulum of the injured cord, thereby reducing neuroapoptosis and improving locomotor function of rats with SCI.

Therapeutic use of extracellular mitochondria in CNS injury and disease

In the central nervous system (CNS), neuronal functionality is highly dependent on mitochondrial integrity and activity. In the context of a damaged or diseased brain, mitochondrial dysfunction leads to reductions in ATP levels, thus impairing ATP-dependent neural firing and neurotransmitter dynamics. Restoring mitochondrial ability to generate ATP may be a basic premise to restore neuronal functionality. Recently, emerging data in rodent and human studies suggest that mitochondria and its components are surprisingly released into extracellular space and potentially transferred between cells. Transferred mitochondria may support oxidative phosphorylation in recipient cells. In this mini-review, we (a) survey recent findings in cell to cell mitochondrial transfer and the presence of cell-free extracellular mitochondria and its components, (b) review experimental details of how to detect extracellular mitochondria and mitochondrial transfer in the CNS, (c) discuss strategies and tissue sources for mitochondria isolation, and (d) explore exogenous mitochondrial transplantation as a novel approach for CNS therapies.

The brain and eye: Treating cerebral and retinal ischemia through mitochondrial transfer

Stroke remains a devastating disease with limited treatment options, despite our growing understanding of its pathology. While ischemic stroke is traditionally characterized by a blockage of blood flow to the brain, this may coincide with reduced blood circulation to the eye, resulting in retinal ischemia, which may in turn lead to visual impairment. Although effective treatment options for retinal ischemia are similarly scarce, new evidence suggests that deleterious changes to mitochondrial structure and function play a major role in both cerebral and retinal ischemia pathologies. Prior studies establish that astrocytes transfer healthy mitochondria to ischemic neurons following stroke; however, this alone is not enough to significantly mitigate the damage caused by primary and secondary cell death. Thus, stem cell-based regenerative medicine targeting amelioration of ischemia-induced mitochondrial dysfunction via the transfer of functional mitochondria to injured neural cells represents a promising approach to improve stroke outcomes for both cerebral and retinal ischemia. In this review, we evaluate recent laboratory evidence supporting the remedial capabilities of mitochondrial transfer as an innovative stroke treatment. In particular, we examine exogenous stem cell transplants in their potential role as suppliers of healthy mitochondria to neurons, brain endothelial cells, and retinal cells.

Impact statement

Stroke constitutes a global health crisis, yet potent, applicable therapeutic options remain effectively inaccessible for many patients. To this end, stem cell transplants stand as a promising stroke treatment and as an emerging subject of research for cell-based regenerative medicine. This is the first review to synthesize the implications of stem cell-derived mitochondrial transfer in both the brain and the eye. As such, this report carries fresh insight into the commonalities between the two stroke-affected organs. We present the findings of this developing area of research inquiry with the hope that our evaluation may advance the use of stem cell transplants as viable therapeutic alternatives for ischemic stroke and related disorders characterized by mitochondrial dysfunction. Such lab-to-clinic translational advancement has the potential to save and improve the ever increasing millions of lives affected by stroke.

Brief overview: Protective roles of astrocyte-derived pentraxin-3 in blood-brain barrier integrity

Stroke is one of the world's leading causes of mortality and morbidity. Greater understanding is required of the underlying relationships in ischemic brains in order to prevent stroke or to develop effective treatment. This review highlights new findings about the relationship of blood–brain barrier with astrocytes, pentraxin-3 (PTX3), and other factors expressed during or after ischemic stroke. These are discussed with respect to their ameliorative or deleterious effects. These effects are measured in vivo in animal models as well as in vitro in cell cultures. Evidence was found to suggest that astrocytes play a key role in stroke by expressing PTX3, which, in turn, enhances endothelial tightness, increases tight junction proteins, and inhibits vascular endothelial growth factor. The role of astrocytes and PTX3 is examined in relation to hypoxic stress and conditioning as well as mitochondrial transfer. Astrocytes and PTX3 are placed in the context of brain circulation and related areas.

Increased interleukin-18 level contributes to the development and severity of ischemic stroke

Although interleukin-18 (IL-18) has been implicated in the pathophysiology of stroke, research findings concerning IL-18 level in stroke have been inconsistent. Thus, we performed a cross-sectional study in patients with first-episode ischemic stroke and then extracted relevant data from databases to validate our results. A total of 252 patients and 259 healthy subjects were recruited, and serum IL-18 level was evaluated in a cross-sectional study. Then, we extracted data and conducted a meta-analysis, including 2,928 patients and 3,739 controls to support our results. A 95% confidence interval for standardized mean difference (SMD) was calculated using a Z test. We found IL-18 was higher in stroke patients than in controls (2.39 ± 0.25 vs. 2.25 ± 0.28, F=8.60, p=0.004) and was negatively associated with the NIHSS scale (r = -0.14, p=0.028). A subsequent meta-analysis confirmed that IL-18 level was higher in stroke patients than in controls (SMD = 2.14, 95% CI = 1.54 ∼ 2.73, P< 0.001). IL-18 level increased with the severity of the stroke (p< 0.01). These findings revealed increased IL-18 level contributed to the development and severity of ischemic stroke, suggesting the potential of this biomarker to become an important reference for the early monitoring of ischemic stroke.

Mitochondrial dysfunction and role in spreading depolarization and seizure

The effect of pathological phenomena such as epileptic seizures and spreading depolarization (SD) on mitochondria and the potential feedback of mitochondrial dysfunction into the dynamics of those phenomena are complex and difficult to study experimentally due to the simultaneous changes in many variables governing neuronal behavior. By combining a model that accounts for a wide range of neuronal behaviors including seizures, normoxic SD, and hypoxic SD (HSD), together with a detailed model of mitochondrial function and intracellular Ca²⁺ dynamics, we investigate mitochondrial dysfunction and its potential role in recovery of the neuron from seizures, HSD, and SD. Our results demonstrate that HSD leads to the collapse of mitochondrial membrane potential and cellular ATP levels that recover only when normal oxygen supply is restored. Mitochondrial organic phosphate and pH gradients determine the strength of the depolarization block during HSD and SD, how quickly the cell enters the depolarization block when the oxygen supply is disrupted or potassium in the bath solution is raised beyond the physiological value, and how fast the cell recovers from SD and HSD when normal potassium concentration and oxygen supply are restored. Although not as dramatic as phosphate and pH gradients, mitochondrial Ca²⁺ uptake has a similar effect on neuronal behavior during these conditions.

Knockdown of TRIM32 Protects Hippocampal Neurons from Oxygen-Glucose Deprivation-Induced Injury

Tripartite motif 32 (TRIM32) is a member of TRIM family that plays a potential role in neural regeneration. However, the biological function of TRIM32 in cerebral ischemia reperfusion injury has not been investigated. In the present study, we evaluated the expression level of TRIM32 in hippocampal neurons following oxygen-glucose deprivation/reperfusion (OGD/R). The results showed that TRIM32 expression was significantly elevated in hippocampal neurons subjected to OGD/R as compared to the neurons cultured in the normoxia condition. To further evaluate the role of TRIM32, hippocampal neurons were transfected with TRIM32 small interfering RNA (si-TRIM32) to knock down TRIM32. We found that knockdown of TRIM32 improved cell viability of OGD/R-stimulated hippocampal neurons. Generation of reactive oxygen species was decreased, while contents of superoxide dismutase and glutathione peroxidase were increased after si-TRIM32 transfection. Knockdown of TRIM32 suppressed cell apoptosis, as proved by the increased bcl-2 expression along with decreased bax expression and caspase-3 activity. We also found that TRIM32 knockdown enhanced OGD/R-induced activation of Nrf2 signaling pathway in hippocampal neurons. Furthermore, siRNA-Nrf2 was transfected to knock down Nrf2. SiRNA-Nrf2 transfection reversed the protective effects of TRIM32 knockdown on neurons. These data suggested that knockdown of TRIM32 protected hippocampal neurons from OGD/R-induced oxidative injury through activating Nrf2 signaling pathway.

Electroacupuncture ameliorates neuronal injury by Pink1/Parkin-mediated mitophagy clearance in cerebral ischemia-reperfusion

The accumulation of dysfunctional mitochondria induced by the impairment of the autophagy-lysosome pathway (ALP), especially mitophagy is an important cause of cerebral ischemia-reperfusion (I/R) injury. Electroacupuncture (EA) exerts remarkable effects in treating ischemic stroke; however, the detailed mechanism remains unclear. In this study, rats were treated with mitochondrial permeability transition pore (mPTP) opening inhibitor, peroxynitrite (ONOO^-) scavenger, or selective inhibitor of mitophagy activation during 2-h middle cerebral artery occlusion (MCAO) followed by 24 h of reperfusion in combination with EA treatment. RNA-Seq analysis showed that EA treatment in cerebral I/R was linked to the autophagosome, the PI3K/Akt signaling pathway and metabolic pathways. We found that I/R resulted in significantly mitochondrial function impairments including decreased mitochondrial membrane potential (MMP) and ATP levels, aggregation of damaged mitochondria, excessive nitro/oxidative stress, PI3K/Akt/mTOR-mediated ALP dysfunction and deficiency of Pink1/Parkin-mediated mitophagy clearance. The treatment with EA, cyclosporine-A (CsA, a potent inhibitor of mPTP opening) or FeTMPyP (a type of ONOO^- scavenger) could significantly increase MMP and/or ATP levels, improve mitochondrial function and decrease neuronal injury. At the same time, EA also improved ALP dysfunction and the deficiency of mitophagy clearance; however, mitochondrial division inhibitor-1 (Mdivi-1, a selective inhibitor of mitophagy activation) blocked mitophagy clearance and aggravated neuronal injury. Taken together, EA ameliorates nitro/oxidative stress-induced mitochondrial functional damage and decreases the accumulation of damaged mitochondria via Pink1/Parkin-mediated mitophagy clearance to protect cells against neuronal injury in cerebral I/R.

Neuroinflammation: friend and foe for ischemic stroke

Stroke, the third leading cause of death and disability worldwide, is undergoing a change in perspective with the emergence of new ideas on neurodegeneration. The concept that stroke is a disorder solely of blood vessels has been expanded to include the effects of a detrimental interaction between glia, neurons, vascular cells, and matrix components, which is collectively referred to as the neurovascular unit. Following the acute stroke, the majority of which are ischemic, there is secondary neuroinflammation that both promotes further injury, resulting in cell death, but conversely plays a beneficial role, by promoting recovery. The proinflammatory signals from immune mediators rapidly activate resident cells and influence infiltration of a wide range of inflammatory cells (neutrophils, monocytes/macrophages, different subtypes of T cells, and other inflammatory cells) into the ischemic region exacerbating brain damage. In this review, we discuss how neuroinflammation has both beneficial as well as detrimental roles and recent therapeutic strategies to combat pathological responses. Here, we also focus on time-dependent entry of immune cells to the ischemic area and the impact of other pathological mediators, including oxidative stress, excitotoxicity, matrix metalloproteinases (MMPs), high-mobility group box 1 (HMGB1), arachidonic acid metabolites, mitogen-activated protein kinase (MAPK), and post-translational modifications that could potentially perpetuate ischemic brain damage after the acute injury. Understanding the time-dependent role of inflammatory factors could help in developing new diagnostic, prognostic, and therapeutic neuroprotective strategies for post-stroke inflammation.

Eventual analysis of global cerebral ischemia-reperfusion injury in rat brain: a paradigm of a shift in stress and its influence on cognitive functions

Cognitive issues in stroke arise as a result of reperfusion of a clogged artery, which is reported to exacerbate the injury in the brain leading to oxidative stress. Through the present work, we try to understand the regional variations across brain regions mainly cortex and striatum associated with the progression of ischemia-reperfusion injury (IRI). In a rat model of IRI, the influence of varying ischemia and reperfusion times on the biochemical phases across the brain regions were monitored. IRI resulted in the blood-brain barrier disruption and developed mild areas of risk. The brain's tolerance towards IRI indicated a progressive trend in the injury and apoptosis from ischemia to reperfusion that was supported by the activities of plasma lactate dehydrogenase and tissue caspase-3. Cognitive impairment in these rats was an implication of cellular oxidative stress (higher lipid peroxidation and lower antioxidant enzyme activity) that persisted by 24-h reperfusion. The oxidative stress was prominent in the cortex than the striatum and was supported by the lower ATP level. Upregulated Mn-SOD expression leading to a preserved mitochondria in the striatum could be attributed to the regional protection. Overall, a progression of IRI was observed from striatum to cortex leading to 5-day cognitive decline.

Astragaloside IV Protects Primary Cerebral Cortical Neurons from Oxygen and Glucose Deprivation/Reoxygenation by Activating the PKA/CREB Pathway

Stroke is one of the major leading causes of death and disability worldwide, and post-stroke cognitive impairment is a major contributor to this disability. Astragaloside IV (AST-IV) is a primary bioactive compound of Radix Astragali, which is widely used in traditional Chinese medicine to treat stroke. AST-IV was found to possess cognition-enhancing properties against ischemic stroke; however, the mechanisms underlying this effect remain largely elusive. Mitochondrial health is critical to cell viability after ischemic injury. Cyclic AMP response element-binding protein (CREB) is a transcription factor that can be activated by protein kinase A (PKA) to preserve mitochondria, regulate memory and cognitive functions. We used an in vitro model of ischemic injury via oxygen and glucose deprivation (OGD) of cultured neurons, which led to PKA inactivation and decreased CREB phosphorylation, reduced cell viability, and increased neuronal apoptosis. We hypothesized that AST-IV could protect OGD-exposed cerebral cortical neurons by modulating the PKA/CREB signaling pathway and preserving mitochondrial function. We found that the mitochondrial and cellular injuries induced by OGD were reversed following treatment with AST-IV. The activity of neuronal mitochondria was evaluated by measuring the mitochondrial potential and the levels of reactive oxygen species (ROS) and adenosine triphosphate (ATP). AST-IV significantly enhanced PKA and CREB phosphorylation and prevented OGD-induced mitochondrial dysfunction, thereby protecting neurons exposed to OGD from injury and death. Furthermore, the effects of AST-IV were partially blocked by a PKA inhibitor. Collectively, these data elucidated the molecular mechanisms underlying the protective effects of AST-IV against ischemic injury in cortical neurons.

Keratan sulfate (KS)-proteoglycans and neuronal regulation in health and disease: the importance of KS-glycodynamics and interactive capability with neuroregulatory ligands

Compared to the other classes of glycosaminoglycans (GAGs), that is, chondroitin/dermatan sulfate, heparin/heparan sulfate and hyaluronan, keratan sulfate (KS), have the least known of its interactive properties. In the human body, the cornea and the brain are the two most abundant tissue sources of KS. Embryonic KS is synthesized as a linear poly-N-acetyllactosamine chain of d-galactose-GlcNAc repeat disaccharides which become progressively sulfated with development, sulfation of GlcNAc is more predominant than galactose. KS contains multi-sulfated high-charge density, monosulfated and non-sulfated poly-N-acetyllactosamine regions and thus is a heterogeneous molecule in terms of chain length and charge distribution. A recent proteomics study on corneal KS demonstrated its interactivity with members of the Slit-Robbo and Ephrin-Ephrin receptor families and proteins which regulate Rho GTPase signaling and actin polymerization/depolymerization in neural development and differentiation. KS decorates a number of peripheral nervous system/CNS proteoglycan (PG) core proteins. The astrocyte KS-PG abakan defines functional margins of the brain and is up-regulated following trauma. The chondroitin sulfate/KS PG aggrecan forms perineuronal nets which are dynamic neuroprotective structures with anti-oxidant properties and roles in neural differentiation, development and synaptic plasticity. Brain phosphacan a chondroitin sulfate, KS, HNK-1 PG have roles in neural development and repair. The intracellular microtubule and synaptic vesicle KS-PGs MAP1B and SV2 have roles in metabolite transport, storage, and export of neurotransmitters and cytoskeletal assembly. MAP1B has binding sites for tubulin and actin through which it promotes cytoskeletal development in growth cones and is highly expressed during neurite extension. The interactive capability of KS with neuroregulatory ligands indicate varied roles for KS-PGs in development and regenerative neural processes.

Healthy mitochondria for stroke cells

Stroke is a debilitating disease that remains as a significant unmet need. Although our understanding of the disease pathology has advanced over the years, treatment options for stroke are limited. Recent studies have implicated the important role of healthy mitochondria in neuroprotection against stroke. Under the stroke pathological condition, transfer of healthy mitochondria is observed from astrocytes to ischemic neurons. However, without additional therapeutic intervention, such astrocyte-to-neuron transfer of mitochondria may not sufficiently afford a robust and stable therapeutic effect against the devastating primary insult and progressive neurodegeneration associated with stroke. We now explore the concept that transplantation of exogenous stem cells may serve as efficacious sources of healthy mitochondria for ischemic cells, not only neurons but also endothelial cells. This review captures the recent advances on the therapeutic potential of mitochondrial transfer as a novel stroke treatment. This paper is a review article. Referred literature in this article has been listed in the references section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed.