Diverse roles of mitochondria in ischemic stroke

Influence of the rs6736 Polymorphism on Ischemic Stroke Susceptibility in Han Chinese Individuals via the Disruption of miR-7-1 Binding to the C14orf119 Gene

This study investigates the association between the C14orf119 gene rs6736 polymorphism and ischemic stroke (IS) susceptibility, and explores the influence of the rs6736 polymorphism on the binding between miR-7-1 and the C14orf119 gene. mRNA expression levels were determined in 45 IS patients and 45 matched controls via real-time quantitative PCR. A total of 774 IS patients and 793 matched controls were recruited from a Han Chinese population for genotyping, performed with the Sequenom MassARRAY iPLEX platform. A dual-luciferase reporter assay was used for the analysis of miRNA-mRNA binding. The results showed that the mRNA expression of C14orf119 differed significantly between IS patients and controls (t =  -2.235, P = 0.030). Significant associations were noted between the C14orf119 gene rs6736 polymorphism and IS susceptibility in Han Chinese individuals under the additive model [OR_adj (95% CI) = 0.87 (0.76-1.00) P_adj = 0.048] and dominant model [OR_adj (95% CI) = 0.76 (0.61-0.94), P_adj = 0.014], with adjustment for age and sex. Mutations in the rs6736 polymorphism disrupted the binding of miR-7-1 and the C14orf119 gene. The results of this study show that the rs6736 polymorphism in the 3'-untranslated region of the C14orf119 gene not only is associated with IS but also modifies the binding between miR-7-1 and the C14orf119 gene. The C14orf119 gene may participate in the relationship between IS and miR-7-1.

Naked mole-rat brain mitochondria tolerate in vitro ischaemia

Naked mole-rats (NMRs; Heterocephalus glaber) are among the most hypoxia-tolerant mammals. There is evidence that the NMR brain tolerates in vitro hypoxia and NMR brain mitochondria exhibit functional plasticity following in vivo hypoxia; however, if and how these organelles tolerate ischaemia and how ischaemic stress impacts mitochondrial energetics and redox regulation is entirely unknown. We hypothesized that mitochondria fundamentally contribute to in vitro ischaemia resistance in the NMR brain. To test this, we treated NMR and CD-1 mouse cortical brain sheets with an in vitro ischaemic mimic and evaluated mitochondrial respiration capacity and redox regulation following 15 or 30 min of ischaemia or ischaemia/reperfusion (I/R). We found that, relative to mice, the NMR brain largely retains mitochondrial function and redox balance post-ischaemia and I/R. Specifically: (i) ischaemia reduced complex I and II-linked respiration ∼50-70% in mice, vs. ∼20-40% in NMR brain, (ii) NMR but not mouse brain maintained relatively steady respiration control ratios and robust mitochondrial membrane integrity, (iii) electron leakage post-ischaemia was lesser in NMR than mouse brain and NMR brain retained higher coupling efficiency, and (iv) free radical generation during and following ischaemia and I/R was lower from NMR brains than mice. Taken together, our results indicate that NMR brain mitochondria are more tolerant of ischaemia and I/R than mice and retain respiratory capacity while avoiding redox derangements. Overall, these findings support the hypothesis that hypoxia-tolerant NMR brain is also ischaemia-tolerant and suggest that NMRs may be a natural model of ischaemia tolerance in which to investigate evolutionarily derived solutions to ischaemic pathology. KEY POINTS: Ischaemia is highly deleterious to the mammalian brain and this damage is largely mediated by mitochondrial dysfunction. Naked mole-rats are among the most hypoxia-tolerant mammals and their brain tolerates ischaemia ex vivo, but the impact of ischaemia on mitochondrial function is unknown. Naked mole-rat but not mouse brain mitochondria retain respiratory capacity and membrane integrity following ischaemia or ischaemia/reperfusion. Differences in free radical management and respiratory pathway control between species may mediate this tolerance. These results help us understand how natural models of hypoxia tolerance also tolerate ischaemia in the brain.

The Alterations in Mitochondrial Dynamics Following Cerebral Ischemia/Reperfusion Injury

Cerebral ischemia results in a poor oxygen supply and cerebral infarction. Reperfusion to the ischemic area is the best therapeutic approach. Although reperfusion after ischemia has beneficial effects, it also causes ischemia/reperfusion (I/R) injury. Increases in oxidative stress, mitochondrial dysfunction, and cell death in the brain, resulting in brain infarction, have also been observed following cerebral I/R injury. Mitochondria are dynamic organelles, including mitochondrial fusion and fission. Both processes are essential for mitochondrial homeostasis and cell survival. Several studies demonstrated that an imbalance in mitochondrial dynamics after cerebral ischemia, with or without reperfusion injury, plays an important role in the regulation of cell survival and infarct area size. Mitochondrial dysmorphology/dysfunction and inflammatory processes also occur after cerebral ischemia. Knowledge surrounding the mechanisms involved in the imbalance in mitochondrial dynamics following cerebral ischemia with or without reperfusion injury would help in the prevention or treatment of the adverse effects of cerebral injury. Therefore, this review aims to summarize and discuss the roles of mitochondrial dynamics, mitochondrial function, and inflammatory processes in cerebral ischemia with or without reperfusion injury from in vitro and in vivo studies. Any contradictory findings are incorporated and discussed.

Generation and Role of Calpain-Cleaved 17-kDa Tau Fragment in Acute Ischemic Stroke

Stroke is the leading cause of permanent disability and death in the world. The therapy for acute stroke is still limited due to the complex mechanisms underlying stroke-induced neuronal death. The generation of a 17-kDa neurotoxic tau fragment was reported in Alzheimer's disease but it has not been well studied in stroke. In this study, we observed the accumulation of 17-kDa tau fragment in cultured primary neurons and media after oxygen-glucose deprivation/reperfusion (OGD/R) treatment that could be diminished by the presence of a calpain inhibitor. This calpain-mediated proteolytic tau fragment was also detected in brain tissues from middle cerebral artery occlusion-injured rats and acute ischemic stroke patients receiving strokectomy, and human plasma samples collected within 48 h after the onset of stroke. The mass spectrometry analysis of this 17-kDa fragment identified 2 peptide sequences containing 195-224 amino acids of tau, which agrees with the previously reported tau_45-230 or tau_125-230 as the calpain-cleaved tau fragment. Ectopic expression of tau_45-230-GFP but not tau_125-230-GFP in cultured neurons induced the formation of tortuous processes without evident cell death. In summary, the 17-kDa tau fragment is a novel stroke biomarker and may play a pathophysiological role to affect post-stroke neuronal health.

The Promoting Effect of Traumatic Brain Injury on the Incidence and Progression of Glioma: A Review of Clinical and Experimental Research

The role of traumatic brain injury in the development of glioma is highly controversial since first presented. This is not unexpected because traumatic brain injuries are overwhelmingly more common than glioma. However, the causes of post-traumatic glioma have been long discussed and still warrant further research. In this review, we have presented an overview of previous cohort studies and case–control studies. We have summarized the roles of microglial cells, macrophages, astrocytes, and stem cells in post-traumatic glioma formation and development, and reviewed various carcinogenic factors involved during traumatic brain injury, especially those reported in experimental studies indicating a relationship with glioma progression. Besides, traumatic brain injury and glioma share several common pathways, including inflammation and oxidative stress; however, the exact mechanism underlying this co-occurrence is yet to be discovered. In this review, we have summarized current epidemiological studies, clinical reports, pathophysiological research, as well as investigations evaluating the probable causes of co-occurrence and treatment possibilities. More efforts should be directed toward elucidating the relationship between traumatic brain injury and glioma, which could likely lead to promising pharmacological interventions towards designing therapeutic strategies.

Compatibility of ingredients of Danshen (Radix Salviae Miltiorrhizae) and Honghua (Flos Carthami) and their protective effects on cerebral ischemia-reperfusion injury in rats

Danshen (Radix Salviae Miltiorrhizae) and Honghua (Flos Carthami) (Danhong) are two drugs commonly prescribed together, which are often used in the treatment of cerebrovascular diseases in China. Due to the complexity of the ingredients of Danhong, the present study focused on performing the orthogonal compatibility method on the primary effective molecules of this drug: Tanshinol, salvianolic acid A, salvianolic acid B and hydroxysafflor yellow A. These four molecules were studied to determine their protective effects and to screen for the most compatible ingredients to improve cerebral ischemia-reperfusion injury (IR) in rats. Focal middle cerebral artery occlusion was performed to establish the cerebral IR model in rats. Male Sprague-Dawley rats were randomly divided into sham operation group, IR group and nine orthogonal administration groups with different ratios of Danhong effective ingredients and Danhong injection group. Neurological deficit score and cerebral infarction volume were measured postoperatively. Morphological pathological alterations were observed via H&E staining. Bcl-2 and Bax were quantified using ELISA. Immunohistochemistry was conducted to analyze the expression of caspase-3 in the hippocampus. The expression levels of cytochrome c, apoptotic peptidase activating factor 1 (apaf-1), caspase-9, caspase-3 and p53 mRNA in the hippocampus were assessed via reverse transcription-quantitative PCR. The results demonstrated that different compatibility groups significantly reduced the neurological function score and decreased the volume of cerebral infarct compared with the IR group. These groups were also indicated to improve the pathological damage to the brain tissue. In addition, certain compatibility groups significantly decreased the number of caspase-3 positive cells in the hippocampus and the expression levels of cytochrome c, apaf-1, caspase-9, caspase-3 and p53 mRNA in the brain tissue. Orthogonal group 4 (30 mg/kg tanshinol; 2.5 mg/kg salvianolic acid A; 16 mg/kg salvianolic acid B; 8 mg/kg hydroxysafflor yellow A) was indicated to be the most effective. The four effective ingredients of Danhong exhibited a protective effect on rats with cerebral IR injury, potentially through the inhibition of apoptosis via the downregulation of key targets upstream of the caspase-3 pathway. In addition, the present study provided novel insights for the continued study of the drug compatibility rules of TCM.

Harnessing the mitochondrial integrity for neuroprotection: Therapeutic role of piperine against experimental ischemic stroke

Ischemic stroke (IS) is a rapidly increasing global burden and is associated with severe neurological decline and mortality. There is urgent requirement of the efforts, aimed to identify therapeutic strategies that are effective in clinic to promote significant recovery from IS. Studies have shown that mitochondria mediated neuroprotection can be a competent target against ischemic damage. Therefore, we examined whether mitochondrial impairment is regulated by Piperine (PIP), an alkaloid of Piper Longum, which has neuroprotective activity against ischemic brain injury. In this study, transient middle cerebral artery occlusion (tMCAO) surgery was performed on male Wistar rats for 90 min followed by 22.5 h of reperfusion for mimicking the IS condition. This study consisted of three groups: sham, tMCAO and tMCAO + PIP (10 mg/kg b.wt., p.o/day for 15 days), and studied for behavioral tests, infarct volume, brain pathological changes, mitochondrial dysfunction, inflammation alongwith cell survival status. PIP pre-treatment showed reduction in neurological alterations and infarct volume. In addition, PIP pre-treatment suppressed the mitochondrial dysfunction and might have anti-apoptotic potential by preventing Cytochrome c (Cyt c) release from mitochondria to cytoplasm and caspase 3 activation. It also regulates pro-apoptotic, Bax and anti-apoptotic, Bcl-2 proteins accompanied by glial fibrillary acidic protein (GFAP) positive cells in cortex region. Quantitative Reverse transcription-polymerase chain reaction (qRT-PCR) results also showed that PIP reduced the expression of pro-inflammatory protein, interleukin-1 β (IL-1β) and enhanced cell survival by restoring the activity of brain derived neurotrophic factor (BDNF) and its transcription protein, cAMP response element binding protein (CREB). Taken together, PIP reduced the mitochondrial dysfunction, neurological impairment, and enhanced neuronal survival. In conclusion, our findings reinforce PIP as an effective neuroprotective agent and provide important evidence about its role as a potential target to serve as a promising therapy for treatment of IS.

Renal Delivery of Pharmacologic Agents During Machine Perfusion to Prevent Ischaemia-Reperfusion Injury: From Murine Model to Clinical Trials

Donor organ shortage still remains a serious obstacle for the access of wait-list patients to kidney transplantation, the best treatment for End-Stage Kidney Disease (ESKD). To expand the number of transplants, the use of lower quality organs from older ECD or DCD donors has become an established routine but at the price of increased incidence of Primary Non-Function, Delay Graft Function and lower-long term graft survival. In the last years, several improvements have been made in the field of renal transplantation from surgical procedure to preservation strategies. To improve renal outcomes, research has focused on development of innovative and dynamic preservation techniques, in order to assess graft function and promote regeneration by pharmacological intervention before transplantation. This review provides an overview of the current knowledge of these new preservation strategies by machine perfusions and pharmacological interventions at different timing possibilities: in the organ donor, ex-vivo during perfusion machine reconditioning or after implementation in the recipient. We will report therapies as anti-oxidant and anti-inflammatory agents, senolytics agents, complement inhibitors, HDL, siRNA and H2S supplementation. Renal delivery of pharmacologic agents during preservation state provides a window of opportunity to treat the organ in an isolated manner and a crucial route of administration. Even if few studies have been reported of transplantation after ex-vivo drugs administration, targeting the biological pathway associated to kidney failure (i.e. oxidative stress, complement system, fibrosis) might be a promising therapeutic strategy to improve the quality of various donor organs and expand organ availability.

Irisin-Associated Neuroprotective and Rehabilitative Strategies for Stroke

Irisin, a newly discovered protein hormone that is secreted in response to low frequency whole body vibration (LFV), could be a promising post-stroke rehabilitation therapy for patients who are frail and cannot comply with regular rehabilitation therapy. Irisin is generated from a membrane-bound precursor protein fibronectin type III domain-containing protein 5 (FNDC5). Aside from being highly expressed in muscle, FNDC5 is highly expressed in the brain. The cleaved form of FNDC5 was found in the cerebrospinal fluid as well as in various regions of the brain. Numerous studies suggest that irisin plays a key role in brain metabolism and inflammation regulation. Both the metabolism and inflammation govern stroke outcome, and in a published study, we demonstrated that LFV therapy following middle cerebral artery occlusion significantly reduced innate immune response, improved motor function and infarct volume in reproductively senescent female rats. The observed effect of LFV therapy could be working via irisin, therefore, the current review focuses to understand various aspects of irisin including its mechanism of action on the brain.

The role of mitochondria in cocaine addiction

The incidence of cocaine abuse is increasing especially in the U.K. where the rates are among the highest in Europe. In addition to its role as a psychostimulant, cocaine has profound effect on brain metabolism, impacting glycolysis and impairing oxidative phosphorylation. Cocaine exposure alters metabolic gene expression and protein networks in brain regions including the prefrontal cortex, the ventral tegmental area and the nucleus accumbens, the principal nuclei of the brain reward system. Here, we focus on how cocaine impacts mitochondrial function, in particular through alterations in electron transport chain function, reactive oxygen species (ROS) production and oxidative stress (OS), mitochondrial dynamics and mitophagy. Finally, we describe the impact of cocaine on brain energy metabolism in the developing brain following prenatal exposure. The plethora of mitochondrial functions altered following cocaine exposure suggest that therapies maintaining mitochondrial functional integrity may hold promise in mitigating cocaine pathology and addiction.

Energy Metabolism Analysis of Three Different Mesenchymal Stem Cell Populations of Umbilical Cord Under Normal and Pathologic Conditions

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are a pivotal source of therapeutically active cells for regenerative medicine due to their multipotent differentiation potential, immunomodulatory and anti-inflammatory proprieties, as well as logistical collection advantages without ethical concerns. However, it remains poorly understood whether MSCs from different compartments of the human umbilical cord are therapeutically superior than others. In this study, MSCs were isolated from Wharton’s jelly (WJ-MSCs), perivascular region (PV-MSCs) and cord lining (CL-MSCs) of hUC. These cells expressed the mesenchymal markers (CD90, CD73), stemness marker (OCT4), endothelial cell adhesion molecular marker (CD146), and the monocyte/macrophage marker (CD14) found within the MSC population implicated as a key regulator of inflammatory responses to hypoxia, was displayed by WJ-, PV-, and CL-MSCs respectively. A direct consequence of oxygen and glucose deprivation during stroke and reperfusion is impaired mitochondrial function that contributes to cellular death. Emerging findings of mitochondria transfer provide the basis for the replenishment of healthy mitochondria as a strategy for the treatment of stroke. Cell Energy Phenotype and Mito Stress tests were performed the energy metabolic profile of the three MSC populations and their mitochondrial function in both ambient and OGD cell culture conditions. PV-MSCs showed the highest mitochondrial activity. CL-MSCs were the least affected by OGD/R condition, suggesting their robust survival in ischemic environment. In this study, MSC populations in UC possess comparable metabolic capacities and good survival under normal and hypoxic conditions suggesting their potential as transplantable cells for mitochondrial-based stem cell therapy in stroke and other ischemic diseases.

Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke

Administration of 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) has been demonstrated to alleviate infarction following ischemic stroke. Reportedly, the main effect of AUDA is exerting anti-inflammation and neovascularization via the inhibition of soluble epoxide hydrolase. However, the major contribution of this anti-inflammation and neovascularization effect in the acute phase of stroke is not completely elucidated. To investigate the neuroprotective effects of AUDA in acute ischemic stroke, we combined laser speckle contrast imaging and optical intrinsic signal imaging techniques with the implantation of a lab-designed cranial window. Forepaw stimulation was applied to assess the functional changes via measuring cerebral metabolic rate of oxygen (CMRO₂) that accompany neural activity. The rats that received AUDA in the acute phase of photothrombotic ischemia stroke showed a 30.5 ± 8.1% reduction in the ischemic core, 42.3 ± 15.1% reduction in the ischemic penumbra (p < 0.05), and 42.1 ± 4.6% increase of CMRO₂ in response to forepaw stimulation at post-stroke day 1 (p < 0.05) compared with the control group (N = 10 for each group). Moreover, at post-stroke day 3, increased functional vascular density was observed in AUDA-treated rats (35.9 ± 1.9% higher than that in the control group, p < 0.05). At post-stroke day 7, a 105.4% ± 16.4% increase of astrocytes (p < 0.01), 30.0 ± 10.9% increase of neurons (p < 0.01), and 65.5 ± 15.0% decrease of microglia (p < 0.01) were observed in the penumbra region in AUDA-treated rats (N = 5 for each group). These results suggested that AUDA affects the anti-inflammation at the beginning of ischemic injury and restores neuronal metabolic rate of O₂ and tissue viability. The neovascularization triggered by AUDA restored CBF and may contribute to ischemic infarction reduction at post-stroke day 3. Moreover, for long-term neuroprotection, astrocytes in the penumbra region may play an important role in protecting neurons from apoptotic injury.

Exposure to oxidized soybean oil induces mammary mitochondrial injury in lactating rats and alters the intestinal barrier function of progeny

Similar to other food contaminants, dietary oxidized soybean oil (OSO) is also a toxic xenobiotic for animal and human nutrition. This research evaluated the effects of maternal OSO exposure during lactation on mammary mitochondrial injury and intestinal barrier of sucking progeny. Twenty-four female adult SD rats were fed a fresh soybean oil (FSO) homozygous diet (7%) or an OSO homozygous diet (7%) during lactation. On day 21 of lactation, upregulated mRNA expression of Sirt3 and PRDX3 and downregulated mRNA expression of Mfn2 were observed in mammary tissues in the OSO group compared to the control group (P < 0.05). Maternal OSO consumption increased the FasL transcriptional level in the mammary glands of rat dams (P < 0.05), while the mRNA expression of Bax, Bcl-2, Caspase3, and Fas was not different from that in the control group (P > 0.05). OSO enhanced the Nrf2 transcriptional level and decreased the expression of Keap1 and PPARα in mammary tissues (P < 0.05). In addition, the contents of CAT, MDA, SOD were not affected by dietary OSO (P > 0.05), while the concentration of H2O2 was significantly decreased in the OSO-treated mammary glands of rat dams (P < 0.05). Maternal OSO exposure during lactation did not affect the organ coefficients of pups (P > 0.05). However, maternal OSO consumption influenced the intestinal tight junction protein expression of progeny (P < 0.05). In summary, the present study demonstrated that dietary OSO may aggravate mammary injury and mitochondria dysfunction, but the OSO-induced damage was self-alleviating via the promotion of Sirt3 and PRDX3 expression and further scavenging of oxidative products.

A nephroprotective iodinated contrast agent with cardioprotective properties: A pilot study

BACKGROUND AND PURPOSE

Evaluation and treatment of acute ischemic syndromes, in the heart and brain, require vessel visualization by iodinated X-ray contrast agents. However, these contrast agents can induce injury, in both the kidneys and target organs themselves. Sulfobutylether beta cyclodextrin (SBECD) added to iohexol (SBECD-iohexol) (Captisol Enabled-iohexol, Ligand Pharmaceuticals, Inc, San Diego, CA) is currently in clinical trials in cardiovascular procedures, to determine its relative renal safety in high-risk patients. Preclinical studies showed that SBECD-iohexol reduced contrast-induced acute kidney injury in rodent models by blocking apoptosis. The current study was undertaken to determine whether SBECD-iohexol is also cardioprotective, in the male rat ischemia-reperfusion model, compared to iohexol alone.

METHODS

After anesthesia, the left coronary artery was ligated for 30 min and the ligation released and reperfusion followed for 2 h prior to sacrifice. Groups 1-4 were injected in the tail vein 10 min prior to ischemia with: (1) vehicle; (2) iohexol; (3) SBECD; and (4) SBECD-iohexol. Infarct size, hemodynamics, and serum markers were measured.

RESULTS

An eight-fold increase in serum creatine kinase in the iohexol-alone group was observed, compared with no increase in the SBECD-iohexol group. The mean arterial pressure and rate pressure product were depressed in the iohexol-alone group, but not in the SBECD-iohexol group, or controls. No difference in infarct size or serum creatinine among the groups was observed.

CONCLUSION

The results of this study suggest that SBECD-iohexol is superior to iohexol alone, for both the preservation of cardiomyocyte integrity and preservation of myocardial function in myocardial ischemia.

Natural products targeting mitochondria: emerging therapeutics for age-associated neurological disorders

Mitochondria are the primary source of energy production in the brain thereby supporting most of its activity. However, mitochondria become inefficient and dysfunctional with age and to a greater extent in neurological disorders. Thus, mitochondria represent an emerging drug target for many age-associated neurological disorders. This review summarizes recent advances (covering from 2010 to May 2020) in the use of natural products from plant, animal, and microbial sources as potential neuroprotective agents to restore mitochondrial function. Natural products from diverse classes of chemical structures are discussed and organized according to their mechanism of action on mitochondria in terms of modulation of biogenesis, dynamics, bioenergetics, calcium homeostasis, and membrane potential, as well as inhibition of the oxytosis/ferroptosis pathway. This analysis emphasizes the significant value of natural products for mitochondrial pharmacology as well as the opportunities and challenges for the discovery and development of future neurotherapeutics.

Insight into the effects of melatonin on endoplasmic reticulum, mitochondrial function, and their cross-talk in the stroke

Ischemic stroke has remained a principal cause of mortality and neurological disabilities worldwide. Blood flow resumption, reperfusion, in the cerebral ischemia prompts a cascade in the brain characterized by various cellular mechanisms like mitochondrial dysfunction, oxidative stresses, endoplasmic reticulum (ER) stress, and excitotoxicity, finally resulting in programmed cell death. Any changes in the ER-mitochondria axis are probably responsible for both the onset and progression of central nervous system diseases. Melatonin, a neurohormone secreted by the pineal gland, has antioxidative, anti-inflammatory, and anti-apoptotic properties. Most studies have shown that it exerts neuroprotective effects against ischemic stroke. It was observed that melatonin therapy after the stroke not only leads to reduce mitochondrial dysfunction but also cause to alleviate ER stress and inflammation. This review discusses the impact of melatonin on mitochondrial, ER function, and on the crosstalk between two organelles as a therapeutic target for stroke. Given that the influences of melatonin on each organelle separately, its effects on mechanisms of crosstalk between ER and mitochondria are discussed.

Galectin-3 Mediated Inflammatory Response Contributes to Neurological Recovery by QiShenYiQi in Subacute Stroke Model

Effective therapies for stroke are still limited due to its complex pathological manifestations. QiShenYiQi (QSYQ), a component-based Chinese medicine capable of reducing organ injury caused by ischemia/reperfusion, may offer an alternative option for stroke treatment and post-stroke recovery. Recently, we reported a beneficial effect of QSYQ for acute stroke via modulation of the neuroinflammatory response. However, if QSYQ plays a role in subacute stroke remains unknown. The pharmacological action of QSYQ was investigated in experimental stroke rats which underwent 90 min ischemia and 8 days reperfusion in this study. Neurological and locomotive deficits, cerebral infarction, brain edema, and BBB integrity were assessed. TMT-based quantitative proteomics were performed to identify differentially expressed proteins following QSYQ treatment. Immunohistochemistry, western blot analysis, RT-qPCR, and ELISA were used to validate the proteomics data and to reveal the action mechanisms. Therapeutically, treatment with QSYQ (600 mg/kg) for 7 days significantly improved neurological recovery, attenuated infarct volume and brain edema, and alleviated BBB breakdown in the stroke rats. Bioinformatics analysis indicated that protein galectin-3 and its mediated inflammatory response was closely related to the beneficial effect of QSYQ. Specially, QSYQ (600 mg/kg) markedly downregulated the mRNA and protein expression levels of galectin-3, TNF-α, and IL-6 in CI/RI brain as well as serum levels of TNF-α and IL-6. Overall, our findings showed that the effective action of QSYQ against the subacute phase of CI/RI occurs partly via regulating galectin-3 mediated inflammatory reaction.

The pyruvate kinase activator mitapivat reduces hemolysis and improves anemia in a β-thalassemia mouse model

Anemia in β-thalassemia is related to ineffective erythropoiesis and reduced red cell survival. Excess free heme and accumulation of unpaired α-globin chains impose substantial oxidative stress on β-thalassemic erythroblasts and erythrocytes, impacting cell metabolism. We hypothesized that increased pyruvate kinase activity induced by mitapivat (AG-348) in the Hbbth3/+ mouse model for β-thalassemia would reduce chronic hemolysis and ineffective erythropoiesis through stimulation of red cell glycolytic metabolism. Oral mitapivat administration ameliorated ineffective erythropoiesis and anemia in Hbbth3/+ mice. Increased ATP, reduced reactive oxygen species production, and reduced markers of mitochondrial dysfunction associated with improved mitochondrial clearance suggested enhanced metabolism following mitapivat administration in β-thalassemia. The amelioration of responsiveness to erythropoietin resulted in reduced soluble erythroferrone, increased liver Hamp expression, and diminished liver iron overload. Mitapivat reduced duodenal Dmt1 expression potentially by activating the pyruvate kinase M2-HIF2α axis, representing a mechanism additional to Hamp in controlling iron absorption and preventing β-thalassemia-related liver iron overload. In ex vivo studies on erythroid precursors from patients with β-thalassemia, mitapivat enhanced erythropoiesis, promoted erythroid maturation, and decreased apoptosis. Overall, pyruvate kinase activation as a treatment modality for β-thalassemia in preclinical model systems had multiple beneficial effects in the erythropoietic compartment and beyond, providing a strong scientific basis for further clinical trials.

Hyperbaric Oxygen Preconditioning Protects Against Cerebral Ischemia/Reperfusion Injury by Inhibiting Mitochondrial Apoptosis and Energy Metabolism Disturbance

Hyperbaric oxygen (HBO) therapy is considered a safe and feasible method that to provide neuroprotection against ischemic stroke. However, the therapy mechanisms of HBO have not been fully elucidated. We hypothesized that the mechanism underlying the protective effect of HBO preconditioning (HBO-PC) against cerebral ischemia/reperfusion injury was related to inhibition of mitochondrial apoptosis and energy metabolism disorder. To test this hypothesis, an ischemic stroke model was established by middle cerebral artery occlusion (MCAO) in rats. HBO-PC involved five consecutive days of pretreatment before MCAO. In additional experiments, X chromosome-linked inhibitor of apoptosis protein (XIAP) and second mitochondria-derived activator of caspases (SMAC) shRNA and NC plasmids were intraventricularly injected into rat brains after MCAO (2 h). After 24 h, all rats underwent motor function evaluation, which was assessed by modified Garcia scores. TTC staining for the cerebral infarct and cerebral edema, and TUNEL staining for cell apoptosis, were also analyzed. Reactive oxygen species and antioxidative enzymes in rat brains were detected, as well as mitochondrial complex enzyme activities, ATP levels, and Na+/K+ ATPase activity. Western blot was used to detect apoptotic proteins including Bcl-2, Bax, caspase-3, caspase-9, cyc-c, XIAP, and SMAC. HBO-PC remarkably reduced the infarct volume and improved neurological deficits. Furthermore, HBO-PC alleviated oxidative stress and regulated the expression of apoptosis-related proteins. Moreover, HBO-PC inhibited the decrease in ATP levels, mitochondrial complex enzyme activities, and Na+/K+ ATPase activity to maintain stable energy metabolism. XIAP knockdown weakened the protective effect of HBO, whereas SMAC knockdown strengthened its protective effect. The effects of HBO-PC can be attributed to inhibition of ischemia/hypoxia-induced mitochondrial apoptosis and energy metabolism disturbance. The action of HBO-PC is related to the XIAP and SMAC signaling pathways.

Mitochondrial activity of human umbilical cord mesenchymal stem cells

Human umbilical cord mesenchymal stem cells (hUC-MSCs) serve as a potential cell-based therapy for degenerative disease. They provide immunomodulatory and anti-inflammatory properties, multipotent differentiation potential and are harvested with no ethical concern. It is unknown whether MSCs collected from different areas of the human umbilical cord elicit more favorable effects than others. Three MSC populations were harvested from various regions of the human umbilical cord: cord lining (CL-MSCs), perivascular region (PV-MSCs), and Wharton's jelly (WJ-MSCs). Mesenchymal markers (CD90 and CD73) were expressed by all three cell populations. Stemness marker (OCT4), endothelial cell adhesion molecular marker (CD146), and monocyte-macrophage marker (CD14) were expressed by WJ-MSCs, PV-MSCs, and CL-MSCs, respectively. Stroke presents with oxygen and glucose deprivation and leads to dysfunctional mitochondria and consequently cell death. Targeting the restoration of mitochondrial function in the stroke brain through mitochondrial transfer may be effective in treating stroke. In vitro exposure to ambient and OGD conditions resulted in CL-MSCs number decreasing the least post-OGD/R exposure, and PV-MSCs exhibiting the greatest mitochondrial activity. All three hUC-MSC populations presented similar metabolic activity and survival in normal and pathologic environments. These characteristics indicate hUC-MSCs potential as a potent therapeutic in regenerative medicine.

Correction of mitochondrial dysfunction by succinic acid derivatives under experimental cerebral ischemia conditions

The aim of the study. To evaluate the effect of succinic acid derivatives on changes of mitochondrial function in rats under cerebral ischemia conditions.

Materials and methods. In this work, the effect of succinic acid, ethylmethylhydroxypyridine succinate, and acetylaminosuccinic acid at doses of 50 mg/kg, 100 mg/kg, and 200 mg/kg (per os) on the change of the neuronal mitochondria function was studied. Cerebral ischemia was reproduced by the Tamura method. The following parameters were evaluated: changes in aerobic/anaerobic metabolism, mitochondrial membrane potential, the opening rate of the mitochondrial pore of transitional permeability and the activity of apoptotic systems.

Results. During the study, it was found that the use of the test-compounds at doses of 100 mg/kg and 200 mg/kg contributed to an increase in ATP-generating activity, as well as the maximum respiration level and respiratory capacity, while accompanied by a decrease in the intensity of anaerobic metabolism reactions. Also, upon administration of the test succinic acid derivatives, an increase in the mitochondrial membrane potential and latent opening time of the mitochondrial pore transitional permeability were observed. Moreover, the activity of caspase-3 and apoptosis-inducing factor on groups treated by test objects at doses of 100 mg/kg and 200 mg/kg was significantly lower than that in untreated animals.

Conclusion. The studied succinic acid derivatives contribute to the restoration of mitochondrial function in cerebral ischemia conditions, while the most effective dose can be considered to be 100 mg/kg.

An updated review of autophagy in ischemic stroke: From mechanisms to therapies

Stroke is a leading cause of mortality and morbidity worldwide. Understanding the underlying mechanisms is important for developing effective therapies for treating stroke. Autophagy is a self-eating cellular catabolic pathway, which plays a crucial homeostatic role in the regulation of cell survival. Increasing evidence shows that autophagy, observed in various cell types, plays a critical role in brain pathology after ischemic stroke. Therefore, the regulation of autophagy can be a potential target for ischemic stroke treatment. In the present review, we summarize the recent progress that research has made regarding autophagy and ischemic stroke, including common signaling pathways, the role of autophagic subtypes (e.g. mitophagy, pexophagy, aggrephagy, endoplasmic reticulum-phagy, and lipophagy) in ischemic stroke, as well as the current methods for autophagy detection and potential therapeutic strategy.

A Commonly Used Biocide 2-N-octyl-4-isothiazolin-3-oneInduces Blood-Brain Barrier Dysfunction via Cellular Thiol Modification and Mitochondrial Damage

Isothiazolinone (IT) biocides are potent antibacterial substances commonly used as preservatives or disinfectants, and 2-n-Octyl-4-isothiazolin-3-one (OIT; octhilinone) is a common IT biocide that is present in leather products, glue, paints, and cleaning products. Although humans are exposed to OIT through personal and industrial use, the potentially deleterious effects of OIT on human health are still unknown. To investigate the effects of OIT on the vascular system, which is continuously exposed to xenobiotics through systemic circulation, we treated brain endothelial cells with OIT. OIT treatment significantly activated caspase-3-mediated apoptosis and reduced the bioenergetic function of mitochondria in a bEnd.3 cell-based in vitro blood–brain barrier (BBB) model. Interestingly, OIT significantly altered the thiol redox status, as evidenced by reduced glutathione levels and protein S-nitrosylation. The endothelial barrier function of bEnd.3 cells was significantly impaired by OIT treatment. OIT affected mitochondrial dynamics through mitophagy and altered mitochondrial morphology in bEnd.3 cells. N-acetyl cysteine significantly reversed the effects of OIT on the metabolic capacity and endothelial function of bEnd.3 cells. Taken together, we demonstrated that the alteration of the thiol redox status and mitochondrial damage contributed to OIT-induced BBB dysfunction, and we hope that our findings will improve our understanding of the potential hazardous health effects of IT biocides.

Pituitary Adenylate Cyclase-Activating Polypeptide: A Potent Therapeutic Agent in Oxidative Stress

Stroke is a life-threatening condition that is characterized by secondary cell death processes that occur after the initial disruption of blood flow to the brain. The inability of endogenous repair mechanisms to sufficiently support functional recovery in stroke patients and the inadequate treatment options available are cause for concern. The pathology behind oxidative stress in stroke is of particular interest due to its detrimental effects on the brain. The oxidative stress caused by ischemic stroke overwhelms the neutralization capacity of the body's endogenous antioxidant system, which leads to an overproduction of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and eventually results in cell death. The overproduction of ROS compromises the functional and structural integrity of brain tissue. Therefore, it is essential to investigate the mechanisms involved in oxidative stress to help obtain adequate treatment options for stroke. Here, we focus on the latest preclinical research that details the mechanisms behind secondary cell death processes that cause many central nervous system (CNS) disorders, as well as research that relates to how the neuroprotective molecular mechanisms of pituitary adenylate cyclase-activating polypeptides (PACAPs) could make these molecules an ideal candidate for the treatment of stroke.

Network Medicine-Based Unbiased Disease Modules for Drug and Diagnostic Target Identification in ROSopathies

Most diseases are defined by a symptom, not a mechanism. Consequently, therapies remain symptomatic. In reverse, many potential disease mechanisms remain in arbitrary search for clinical relevance. Reactive oxygen species (ROS) are such an example. It is an attractive hypothesis that dysregulation of ROS can become a disease trigger. Indeed, elevated ROS levels of various biomarkers have been correlated with almost every disease, yet after decades of research without any therapeutic application. We here present a first systematic, non-hypothesis-based approach to transform this field as a proof of concept for biomedical research in general. We selected as seed proteins 9 families with 42 members of clinically researched ROS-generating enzymes, ROS-metabolizing enzymes or ROS targets. Applying an unbiased network medicine approach, their first neighbours were connected, and, based on a stringent subnet participation degree (SPD) of 0.4, hub nodes excluded. This resulted in 12 distinct human interactome-based ROS signalling modules, while 8 proteins remaining unconnected. This ROSome is in sharp contrast to commonly used highly curated and integrated KEGG, HMDB or WikiPathways. These latter serve more as mind maps of possible ROS signalling events but may lack important interactions and often do not take different cellular and subcellular localization into account. Moreover, novel non-ROS-related proteins were part of these forming functional hybrids, such as the NOX5/sGC, NOX1,2/NOS2, NRF2/ENC-1 and MPO/SP-A modules. Thus, ROS sources are not interchangeable but associated with distinct disease processes or not at all. Module members represent leads for precision diagnostics to stratify patients with specific ROSopathies for precision intervention. The upper panel shows the classical approach to generate hypotheses for a role of ROS in a given disease by focusing on ROS levels and to some degree the ROS type or metabolite. Low levels are considered physiological; higher amounts are thought to cause a redox imbalance, oxidative stress and eventually disease. The source of ROS is less relevant; there is also ROS-induced ROS formation, i.e. by secondary sources (see upwards arrow). The non-hypothesis-based network medicine approach uses genetically or otherwise validated risk genes to construct disease-relevant signalling modules, which will contain also ROS targets. Not all ROS sources will be relevant for a given disease; some may not be disease relevant at all. The three examples show (from left to right) the disease-relevant appearance of an unphysiological ROS modifier/toxifier protein, ROS target or ROS source.

USP30 protects against oxygen-glucose deprivation/reperfusion induced mitochondrial fragmentation and ubiquitination and degradation of MFN2

Cerebral ischemia-reperfusion induces mitochondrial fragmentation and dysfunction, which plays a critical role in the subsequent neuronal death and neurological impairment. Protection of mitochondria is an effective strategy to prevent neuronal damage after cerebral ischemia-reperfusion injury. USP30 is a deubiquitinating enzyme that localizes to the outer mitochondrial membrane. USP30 participates in the regulation of mitophagy and maintenance of mitochondrial morphology. In this study, the neuroprotective effect of USP30 and the underlying mechanisms were assessed in an ischemia-reperfusion injury model. SK-N-BE (2) cells were subjected to oxygen-glucose deprivation/reperfusion (OGDR) insult. Ubiquitination of mitochondrial proteins is increased during the early stage of reperfusion after oxygen-glucose deprivation (OGD), but the ubiquitination of cytoplasmic proteins exhibits no obvious changes. OGDR insult also induces rapid ubiquitination and degradation of the mitochondrial fusion protein mitofusin 2 (MFN2) in the early stage of reperfusion after OGD. Overexpression of MFN2 attenuates OGDR induced mitochondrial fragmentation. USP30 overexpression suppresses OGDR-induced ubiquitination and degradation of MFN2, and protects against mitochondrial fragmentation. Therefore, precisely targeting USP30 may provide a novel therapeutic strategy for cerebral ischemia-reperfusion related disorders.

Personalized Consideration of Admission-Glucose Gap between Estimated Average and Initial Glucose Levels on Short-Term Stroke Outcome

BACKGROUND

Poststroke hyperglycemia is associated with poor outcomes. Most prior studies used initial glucose as an indicator of poststroke hyperglycemia without considering glycemic control status at the time of stroke occurrence. We aimed to investigate the effect of an admission-glucose gap on short-term functional outcomes in acute ischemic stroke (AIS).

METHODS

We enrolled patients with AIS or transient ischemic attack who had been admitted within 7 days of symptom onset to three stroke centers from May 2016 to December 2019. The admission-glucose gap between estimated average glucose levels (eAG) and initial glucose level (eAG-initial glucose) was categorized into four groups. The short-term functional outcome was evaluated using the modified Rankin Scale (mRS) score at 3 months after stroke onset and was dichotomized.

RESULTS

Among 1332 included subjects, 548 (41.1%) had poor short-term functional outcomes. After adjusting for multiple variables, a severe negative glucose gap (eAG-initial glucose ≤ -50 mg/dL) was significantly associated with poor short-term functional outcome (OR, 1.573; 95% CI, 1.101-2.248). After dichotomizing glycemic control status, its significance was only maintained in the good glycemic control group (HbA1c < 6.5%) (OR, 1.914; 95% CI, 1.155-3.169).

CONCLUSIONS

An elevated admission-glucose gap, in which the initial glucose level was much higher than the estimated glucose level was based on HbA1c, was associated with poor stroke prognosis. In addition to admission-glucose levels, glycemic control status at the time of stroke onset should be considered when predicting short-term stroke outcomes.

Apelin-36 Protects HT22 Cells Against Oxygen-Glucose Deprivation/Reperfusion-Induced Oxidative Stress and Mitochondrial Dysfunction by Promoting SIRT1-Mediated PINK1/Parkin-Dependent Mitophagy

Oxidative stress and mitochondrial dysfunction are involved in cerebral ischemia/reperfusion injury-induced neuronal apoptosis. Mitophagy is the main method to eliminate dysfunctional mitochondria. Apelin-36, a type of neuropeptide, has been reported to exert protective effects in cerebral I/R (I/R) injury, but its precise mechanisms remain to be elucidated. To study the effects of Apelin-36 on oxidative stress and mitochondrial dysfunction in cerebral I/R injury, the oxygen-glucose deprivation/reperfusion (OGD/R) model with 6 h of ischemia and 6 h of reperfusion was established in HT22 cells. Results demonstrated that Apelin-36 protected against OGD/R injury by improving cell viability, decreasing the apoptotic cells ratio and increasing the ratio of Bcl-2/Bax. In addition, Apelin-36 treatment inhibited oxidative stress by downregulating the level of reactive oxygen species (ROS) and malondialdehyde (MDA) as well as the expression of inducible nitric oxide synthase (iNOS). And Apelin-36 also activated the level of superoxide dismutase (SOD) and glutathione (GSH). Mitochondrial apoptosis was also alleviated with Apelin-36 treatment detected by the mitochondrial membrane potential (MMP) and the expression of Cytochrome c (Cyt c), Cleaved caspase-9, and Cleaved caspase-3. Furthermore, the SIRT1-mediated PINK1/Parkin-dependent mitophagy was activated by Apelin-36 treatment with the downregulation of p62 and upregulation of LC3B-II and Beclin1. Both EX527 and Cyclosporine A (CsA), which are inhibitors of SIRT1 and mitophagy, markedly alleviated the inhibition of oxidative stress and mitochondrial dysfunction caused by Apelin-36. These findings suggest that SIRT1-mediated PINK1/Parkin-dependent mitophagy is involved in the neuroprotective effects of Apelin-36 on OGD/R-induced oxidative stress and mitochondrial dysfunction.

Neuroprotective effects of human amniotic fluid stem cells-derived secretome in an ischemia/reperfusion model

Stem cells offer the basis for the promotion of robust new therapeutic approaches for a variety of human disorders. There are still many limitations to be overcome before clinical therapeutic application, including a better understanding of the mechanism by which stem cell therapies may lead to enhanced recovery. In vitro investigations are necessary to dissect the mechanisms involved and to support the potential development in stem cell-based therapies. In spite of growing interest in human amniotic fluid stem cells, not much is known about the characteristics of their secretome and regarding the potential neuroprotective mechanism in different pathologies, including stroke. To get more insight on amniotic fluid cells therapeutic potential, signal transduction pathways activated by human amniotic fluid stem cells (hAFSCs)-derived secretome in a stroke in vitro model (ischemia/reperfusion [I/R] model) were investigated by Western blot. Moreover, miRNA expression in the exosomal fraction of the conditioned medium was analyzed. hAFSCs-derived secretome was able to activate pro-survival and anti-apoptotic pathways. MicroRNA analysis in the exosomal component revealed a panel of 16 overexpressed miRNAs involved in the regulation of coherent signaling pathways. In particular, the pathways of relevance in ischemia/reperfusion, such as neurotrophin signaling, and those related to neuroprotection and neuronal cell death, were analyzed. The results obtained strongly point toward the neuroprotective effects of the hAFSCs-conditioned medium in the in vitro stroke model here analyzed. This can be achieved by the modulation and activation of pro-survival processes, at least in part, due to the activity of secreted miRNAs.

Label-Free Liquid Chromatography-Mass Spectrometry Proteomic Analysis of Urinary Identification in Diabetic Vascular Dementia in a Han Chinese Population

Objective: This study aimed to identify potential diagnostic biomarkers of diabetic vascular dementia (DVD) and unravel the underlying mechanisms using mass spectrometry (MS).

Methods: Label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic analysis was applied to urine samples from four groups, including 14 patients with vascular dementia (VD), 22 patients with type 2 diabetes mellitus (T2DM), 12 patients with DVD, and 21 normal controls (NCs). Searching the MS data by Proteome Discoverer software (ThermoFisher Scientific; Waltham, MA, USA), protein abundances were analyzed qualitatively and quantitatively and compared between these groups. Combining bioinformatics analysis using Gene Ontology (GO), pathway crosstalk analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG), protein–protein interaction (PPI) network analysis using STRING, and literature searching, the differentially expressed proteins (DEPs) of DVD can be comprehensively judged and were further quantified by receiver operating characteristic (ROC) curve methods.

Results: The proteomic findings showed quantitative changes in patients with DVD compared to patients with NC, T2DM, and VD groups; among 4,744 identified urine proteins, 1,222, 1,152, and 1,180 proteins displayed quantitative changes unique to DVD vs. NC, T2DM, and VD, respectively, including 481 overlapped common DEPs. Then, nine unique proteins [including HP, SERPIND, ATP5PB, VNN2, ALDH3A1, U2AF2, C6, A0A5C2GRG5 (no name), and A0A5C2FZ29 (no name)] and two composite markers (CM) (A0A5C2GRG5+U2AF2 and U2AF2+C6) were confirmed by a ROC curve method.

Conclusion: This study provided an insight into the potential pathogenesis of DVD and elucidated a method for early detection.

Palmitic acid methyl ester inhibits cardiac arrest-induced neuroinflammation and mitochondrial dysfunction

We previously discovered that palmitic acid methyl ester (PAME) is a potent vasodilator released from the sympathetic ganglion with vasoactive properties. Post-treatment with PAME can enhance cortical cerebral blood flow and functional learning and memory, while inhibiting neuronal cell death in the CA1 region of the hippocampus under pathological conditions (i.e. cerebral ischemia). Since mechanisms underlying PAME-mediated neuroprotection remain unclear, we investigated the possible neuroprotective mechanisms of PAME after 6 min of asphyxial cardiac arrest (ACA, an animal model of global cerebral ischemia). Our results from capillary-based immunoassay (for the detection of proteins) and cytokine array suggest that PAME (0.02 mg/kg) can decrease neuroinflammatory markers, such as ionized calcium binding adaptor molecule 1 (Iba1, a specific marker for microglia/macrophage activation) and inflammatory cytokines after cardiopulmonary resuscitation. Additionally, the mitochondrial oxygen consumption rate (OCR) and respiratory function in the hippocampal slices were restored following ACA (via Seahorse XF24 Extracellular Flux Analyzer) suggesting that PAME can ameliorate mitochondrial dysfunction. Finally, hippocampal protein arginine methyltransferase 1 (PRMT1) and PRMT8 are enhanced in the presence of PAME to suggest a possible pathway of methylated fatty acids to modulate arginine-based enzymatic methylation. Altogether, our findings suggest that PAME can provide neuroprotection in the presence of ACA to alleviate neuroinflammation and ameliorate mitochondrial dysfunction.

CDK5 inhibition protects against OGDR induced mitochondrial fragmentation and apoptosis through regulation of Drp1S616 phosphorylation

AIMS

Cyclin-dependent kinase 5 (CDK5) is a potential target for the treatment of cerebral ischemia. CDK5 is one of the upstream regulators for Dynamin-related protein 1 (Drp1) phosphorylation. This study intends to discuss whether CDK5 inhibition conferring neuroprotection in cerebral ischemia through regulating Drp1 phosphorylation.

MATERIALS AND METHODS

Mouse neuroblastoma N2a cells and N1E-115 cells were cultured and subjected to oxygen-glucose deprivation/reperfusion (OGDR). N2a cells and N1E-115 cells were treated with Roscovitine, a pharmacological inhibitor of CDK5, or transfected with CDK5 siRNA to knock down CDK5 expression. N2a cells were transfected with different plasmids (Drp1-Myc, the dephosphorylation-mimic mutant Drp1S616A-Myc and the phosphorylation-mimic mutant Drp1S616D-Myc). The expression of CDK5 and its activator p35, Drp1 and phosphorylated Drp1 on S616 was determined by western blot. The morphology of mitochondria was detected by immunofluorescence staining and the proportion of N2a cells with apoptosis was detected by flow cytometry analysis.

KEY FINDINGS

Expression of CDK5, p35 and phosphorylated Drp1 on S616 was strongly upregulated after 4 h and 12 h reperfusion following 4 h oxygen-glucose deprivation (OGD) at protein level. CDK5 inhibition by pre-treated with Roscovitine or transfection with CDK5 siRNA significantly ameliorated OGDR induced mitochondrial fragmentation and apoptosis. Overexpression of the phosphorylation-mimic mutant Drp1S616D abrogated the protective effect of CDK5 inhibition against OGDR induced mitochondrial fragmentation and apoptosis.

SIGNIFICANCE

Our data indicate that the neuroprotective effect of CDK5 inhibition against OGDR induced neuronal damage is Drp1S616 phosphorylation dependent. A better understanding of the neuroprotective mechanisms of CDK5 inhibition in cerebral ischemia will help to develop safe and efficacious drugs targeting CDK5 signaling for clinical use.

Regulating Mitochondrial pH with Light and Implications for Chemoresistance

Chemoresistance is one of the major challenges for cancer treatment, more recently ascribed to defective mitochondrial outer membrane permeabilization (MOMP), significantly diminishing chemotherapeutic agent-induced apoptosis. A boron-dipyrromethene (BODIPY) chromophore-based triarylsulfonium photoacid generator (BD-PAG) was used to target mitochondria with the aim to regulate mitochondrial pH and further depolarize the mitochondrial membrane. Cell viability assays demonstrated the relative biocompatibility of BD-PAG in the dark while live cell imaging suggested high accumulation in mitochondria. Specific assays indicated that BD-PAG is capable of regulating mitochondrial pH with significant effects on mitochondrial membrane depolarization. Therapeutic tests using chlorambucil in combination with BD-PAG revealed a new strategy in chemoresistance suppression.

Electroacupuncture Improves Cerebral Ischemic Injury by Enhancing the EPO-JAK2-STAT5 Pathway in Rats

OBJECTIVE

Clinically, electroacupuncture (EA) improves cerebral ischemic injury, but its mechanism remains unknown. The aim of this study was to confirm the protective effects of EA on focal cerebral ischemia (FCI)-induced injury and the possible mechanism.

METHODS

Sprague-Dawley (SD) rats served as the FCI model and were divided into the sham, model, EA, AG490 and EA+AG490 groups. Rats in the EA and EA+AG490 groups were acupunctured at the Baihui (GV20) and Dazhui (GV14) acupoints, and those in the AG490 and EA+AG490 groups were administered an intracerebroventricular injection of AG490 (a Janus-tyrosine kinase-2 (JAK-2) phosphorylation inhibitor). Neurological deficits and morphological changes in the ischemic cortex were observed through neurological deficit scoring and HE staining, respectively, and neuronal apoptosis was examined using the TUNEL assay. Transmission electron microscopy was used to observe neuronal ultrastructure, and HIF-1α, erythropoietin (EPO), phosphorylated (p)-JAK2, p-STAT5, HSP70, Bax and Bcl-2 expression was measured by RT-PCR and immunohistochemistry.

RESULTS

FCI model rats showed obvious neurological deficits and neuronal apoptosis compared with sham rats. EA alleviated FCI-induced neurological deficits, improved neuronal ultrastructure, reduced neuronal apoptosis, and induced HIF-1α, EPO, p-JAK2, p-STAT5, HSP70 and Bcl-2 expression in a time-dependent manner. In contrast, AG490 treatment impaired the effects of EA on neurological deficits, neuronal apoptosis and HIF-1α, EPO, p-JAK2, p-STAT5, HSP70, Bax and Bcl-2 expression.

CONCLUSION

EA at GV20 and GV14 could improve neurological deficits and reduce neuronal apoptosis, thereby improving FCI-induced injury, which may be related to enhancing the EPO-JAK2-STAT5 pathway.

Stem cell secretome derived from human amniotic fluid affords neuroprotection in an ischemic model

Human amniotic fluid stem cells (hAFSCs) are growing in interest; yet, little is understood about their secretome and neuroprotective actions in different diseases, including stroke. When stem cells are grown in vitro, they release an array of cytokines and growth factors that can stimulate neuroprotective processes. Furthermore, administering secretome rather than cells may be a safer route for patients who are at risk for rejection, promoting innate restorative processes. Current literature implicates that the miRNA contents of such secretome, more specifically exosomes, may regulate the effectiveness of secretome administration. In this review, we explore what factors may promote pro-survival and pro-apoptotic pathways after the administration of hAFSCs-derived secretome in ischemic models.

The Role of Mitophagy in Ischemic Stroke

Mitochondria are important places for eukaryotes to carry out energy metabolism and participate in the processes of cell differentiation, cell information transmission, and cell apoptosis. Autophagy is a programmed intracellular degradation process. Mitophagy, as a selective autophagy, is an evolutionarily conserved cellular process to eliminate dysfunctional or redundant mitochondria, thereby fine-tuning the number of mitochondria and maintaining energy metabolism. Many stimuli could activate mitophagy to regulate related physiological processes, which could ultimately reduce or aggravate the damage caused by stimulation. Stroke is a common disease that seriously affects the health and lives of people around the world, and ischemic stroke, which is caused by cerebral vascular stenosis or obstruction, accounts for the vast majority of stroke. Abnormal mitophagy is closely related to the occurrence, development and pathological mechanism of ischemic stroke. However, the exact mechanism of mitophagy involved in ischemic stroke has not been fully elucidated. In this review, we discuss the process and signal pathways of mitophagy, the potential role of mitophagy in ischemic stroke and the possible signal transduction pathways. It will help deepen the understanding of mitophagy and provide new ideas for the treatment of ischemic stroke.

Protective effects of polysaccharides on cerebral ischemia: A mini-review of the mechanisms

Cerebral ischemia, a common cerebrovascular disease, is one of the great threats to human health. Nowadays, many drugs used in the treatment of cerebral ischemia such as clot busting drugs, antiplatelet drugs, and neuroprotective drugs have limits. It is urgent finding new effective treatments for the patients. Researches have confirmed that many kinds of polysaccharides from natural resources possess therapeutic effects on cerebral ischemia, but are still lack of a comprehensively understanding. In this paper, based on the pathophysiology of cerebral ischemic injury, we summarize the latest discoveries and advancements of 29 kinds of polysaccharides, focusing on their ameliorating effects on cerebral ischemia and the underlying mechanisms. Several mechanisms are involved, mainly including antioxidant activities, anti-inflammatory activities, regulating neuron apoptosis, as well as resisting nitrosative stress injury. Besides, polysaccharides show protective effects through certain signaling pathways including PI3K/Akt, MAPK, and NF-κB, PARP-1/AIF, JNK3/c-Jun/Fas-L, and Nrf2/HO-1 signaling pathways. The main goal of this mini-review is to emphasize the important roles of polysaccharides in attenuating cerebral ischemic injury through the elucidation of mechanisms.

The Role of Mitochondria in Brain Cell Protection from Ischaemia by Differently Prepared Propolis Extracts

Mitochondria are both the primary targets and mediators of ischaemic damage in brain cells. Insufficient oxygen causes reactive oxygen species that damage the mitochondria, leading to the loss of functionality and viability of highly energy-demanding neurons. We have recently found that aqueous (AqEP), polyethylene glycol-aqueous (Pg-AqEP) and ethanolic propolis extracts (EEP) can modulate mitochondria and ROS production in C6 cells of astrocytic origin. The aim of this study was to investigate the effect of the extracts on viability, mitochondrial efficiency and superoxide generation, and inflammatory cytokine release in primary rat cerebellar neuronal-glial cell cultures affected by ischaemia (mimicked by hypoxia +/- deoxyglucose). AqEP and Pg-AqEP (15-60 µg/mL of phenolic compounds, or PC) significantly increased neuronal viability in ischaemia-treated cultures, and this was accompanied by a reduction in mitochondrial superoxide levels. Less extended protection against ischaemia-induced superoxide production and death was exhibited by 2 to 4 µg/mL of PC EEP. Both Pg-AqEP and Ag-EP (but not EEP) significantly protected the cultures from hypoxia-induced elevation of TNF-α, IL-1β and IL-6. Only Pg-AqEP (but not AqEP or EEP) prevented hypoxia-induced loss of the mitochondrial basal and ATP-coupled respiration rate, and significantly increased the mitochondrial respiratory capacity. Summarising, the study revealed that hydrophilic propolis extracts might protect brain cells against ischaemic injury by decreasing the level of mitochondrial superoxide and preventing inflammatory cytokines, and, in the case of Pg-AqEP, by protecting mitochondrial function.

l-Borneol ameliorates cerebral ischaemia by downregulating the mitochondrial calcium uniporter-induced apoptosis cascade in pMCAO rats

OBJECTIVES

Stroke is one of the leading causes of disability and death worldwide, and ischaemic stroke is the most common subtype. Moreover, we found that L-borneol has an obvious therapeutic effect on cerebral ischaemia. This study aimed to investigate the potential mechanism of L-borneol in permanent middle cerebral artery occlusion (pMCAO) rats via the mitochondrial calcium uniporter (MCU)-related apoptosis cascade.

METHODS

A pMCAO model was used to simulate cerebral ischaemia, and neurological function was evaluated. Cerebral infarction was observed by TTC staining. HE staining was also used to reflect the pathophysiological changes in the rat hippocampus and cortex. Furthermore, MCU-related signals and apoptosis signalling pathways were detected at both the gene and protein levels.

RESULTS

The neurological function scores of the high-dose L-borneol (H-B) group, medium-dose L-borneol (M-B) group and low-dose L-borneol (L-B) group were significantly lower than that of the model group at 24 h (P < 0.05, P < 0.01). High and medium doses of L-borneol could reverse the cerebral infarction area, similar to Nimotop. After HE staining, the cells in the H-B group and M-B group were neatly and densely arranged, with largely normal morphological structures. High-dose L-borneol could significantly reduce the gene and protein levels of Apaf-1, Bad and Caspase-3 and increase the expression of Bcl-2 (P < 0.05, P < 0.01). In addition, the MCU expression of the H-B group was significantly decreased compared with that of the model group at both the gene and protein levels (P < 0.05, P < 0.01). The expression of IDH2 was similar to that of MCU but not MEP (P < 0.05, P < 0.01).

CONCLUSION

L-borneol can achieve brain protection by downregulating the excessive expression of MCU-related signalling pathway and further inhibiting the apoptosis of neurons during pMCAO.

Therapeutic potential of nutraceuticals to protect brain after stroke

Stroke leads to significant neuronal death and long-term neurological disability due to synergistic pathogenic mechanisms. Stroke induces a change in eating habits and in many cases, leads to undernutrition that aggravates the post-stroke pathology. Proper nutritional regimen remains a major strategy to control the modifiable risk factors for cardiovascular and cerebrovascular diseases including stroke. Studies indicate that nutraceuticals (isolated and concentrated form of high-potency natural bioactive substances present in dietary nutritional components) can act as prophylactic as well as adjuvant therapeutic agents to prevent stroke risk, to promote ischemic tolerance and to reduce post-stroke consequences. Nutraceuticals are also thought to regulate blood pressure, delay neurodegeneration and improve overall vascular health. Nutraceuticals potentially mediate these effects by their powerful antioxidant and anti-inflammatory properties. This review discusses the studies that have highlighted the translational potential of nutraceuticals as stroke therapies.

Apigenin-7-O-β-D-(-6"-p-coumaroyl)-glucopyranoside treatment elicits a neuroprotective effect through GSK-3β phosphorylation-mediated Nrf2 activation

The current study was designed to seek the role of the glycogen synthase kinase-3β (GSK-β)-regulated NF-E2-related factor 2 (Nrf2) pathway in the antioxidant effect induced by Apigenin-7-O-β-D-(-6”-p-coumaroyl)-glucopyranoside (APG). Rat primary cultured cortical neurons were challenged by oxygen and glucose deprivation/reoxygenation (OGD/R) and then treated with APG. Cell viability, phosphorylation of GSK-β at Ser9 and nuclear expression of Nrf2 were measured. Male Sprague Dawley rats challenged by 2-h middle cerebral artery occlusion were treated with 50 mg/kg APG, and the neurological score, infarct volume, phosphorylation of GSK-3β and nuclear expression of Nrf2 were analyzed. The neuroprotective effect of APG and the expression levels of antioxidant enzymes and oxidative products were also examined in the presence and absence of Nrf2-siRNA and PI3K inhibitors. APG reduced the apoptotic proportion, attenuated LDH release and increased cell viability, and in vivo, APG improved neurological scores and reduced infarct volume. APG increased GSK-3β phosphorylation and Nrf2 nuclear translocation, while these effects were prevented by PI3K inhibitors or Nrf2-siRNA treatment in both OGD/R cell cultures and ischemic/reperfusion rats. These findings reveal that GSK-3β phosphorylation-mediated Nrf2 activation is involved in the neuroprotective effect of APG.

Cytochrome c oxidase-modulatory near-infrared light penetration into the human brain: Implications for the noninvasive treatment of ischemia/reperfusion injury

Near-infrared light (IRL) has been evaluated as a therapeutic for a variety of pathological conditions, including ischemia/reperfusion injury of the brain, which can be caused by an ischemic stroke or cardiac arrest. Strategies have focused on modulating the activity of mitochondrial electron transport chain (ETC) enzyme cytochrome c oxidase (COX), which has copper centers that broadly absorb IRL between 700 and 1,000 nm. We have recently identified specific COX-inhibitory IRL wavelengths that are profoundly neuroprotective in rodent models of brain ischemia/reperfusion through the following mechanism: COX inhibition by IRL limits mitochondrial membrane potential hyperpolarization during reperfusion, which otherwise causes reactive oxygen species (ROS) production and cell death. Prior to clinical application of IRL on humans, IRL penetration must be tested, which may be wavelength dependent. In the present study, four fresh (unfixed) cadavers and isolated cadaver tissues were used to examine the transmission of infrared light through human biological tissues. We conclude that the transmission of 750 and 940 nm IRL through 4 cm of cadaver head supports the viability of IRL to treat human brain ischemia/reperfusion injury and is similar for skin with different skin pigmentation. We discuss experimental difficulties of working with fresh cadavers and strategies to overcome them as a guide for future studies.

Sex differences in renal mitochondrial function: a hormone-gous opportunity for research

Sex differences (biological distinctions between males and females) present a complex interplay of genetic, developmental, biological, and environmental factors. More and more studies are shedding light on the importance of sex differences in normal physiology and susceptibility to cancer, cardiovascular and renal conditions, and neurodegenerative diseases. This mini-review is devoted to the role of sex dimorphisms in renal function, with a focus on the distinctions between male and female mitochondria. Here, we cover the aspects of renal mitochondrial bioenergetics where sex differences have been reported to date, for instance, biogenesis, reactive oxygen species production, and oxidative stress. Special attention is devoted to the effects of sex hormones, such as estrogen and testosterone, on mitochondrial bioenergetics in the kidney in physiology and pathophysiology.

Seizure-Induced Oxidative Stress in Status Epilepticus: Is Antioxidant Beneficial?

Epilepsy is a common neurological disorder which affects patients physically and mentally and causes a real burden for the patient, family and society both medically and economically. Currently, more than one-third of epilepsy patients are still under unsatisfied control, even with new anticonvulsants. Other measures may be added to those with drug-resistant epilepsy. Excessive neuronal synchronization is the hallmark of epileptic activity and prolonged epileptic discharges such as in status epilepticus can lead to various cellular events and result in neuronal damage or death. Unbalanced oxidative status is one of the early cellular events and a critical factor to determine the fate of neurons in epilepsy. To counteract excessive oxidative damage through exogenous antioxidant supplements or induction of endogenous antioxidative capability may be a reasonable approach for current anticonvulsant therapy. In this article, we will introduce the critical roles of oxidative stress and further discuss the potential use of antioxidants in this devastating disease.

Crosstalk Between Autophagy and Ferroptosis and Its Putative Role in Ischemic Stroke

Autophagy is a conserved process to maintains homeostasis via the degradation of toxic cell contents, which can either promote cell survival or accelerate cellular demise. Ferroptosis is a recently discovered iron-dependent cell death pathway associated with the accumulation of lethal reactive lipid species. In the past few years, an increasing number of studies have suggested the crosstalk between autophagy and ferroptosis. Ischemic stroke is a complex brain disease regulated by several cell death pathways, including autophagy and ferroptosis. However, the potential links between autophagy and ferroptosis in ischemic stroke have not yet been explored. In this review, we briefly overview the mechanisms of ferroptosis and autophagy, as well as their possible connections in ischemic stroke. The elucidation of crosstalk between different cell death pathways may provide insight into new future ischemic stroke therapies.

Mesenchymal Stem Cell-Mediated Mitochondrial Transfer: a Therapeutic Approach for Ischemic Stroke

Stroke is the leading cause of death and adult disability worldwide. Mitochondrial dysfunction is one of the hallmarks of stroke-induced neuronal death, and maintaining mitochondrial function is essential in cell survival and neurological progress following ischemic stroke. Stem cell-mediated mitochondrial transfer represents an emerging therapeutic approach for ischemic stroke. Accumulating evidence suggests that mesenchymal stem cells (MSCs) can directly transfer healthy mitochondria to damaged cells, and rescue mitochondrial damage-provoked tissue degeneration. This review summarizes the research on MSCs-mediated mitochondrial transfer as a therapeutic strategy against ischemic stroke.

Chromon-3-aldehyde derivatives restore mitochondrial function in rat cerebral ischemia

Objectives

This work aimed to assess the effect of 10 new chromon-3-aldehyde derivatives on changes of mitochondrial function under the conditions of brain ischemia in rats.

Materials and Methods

The work was executed on BALB/c male-mice (acute toxicity was evaluated) and male Wistar rats, which were used to model cerebral ischemia by permanent middle cerebral artery occlusion. The test-substances, 10 derivatives of chromon-3-aldehyde and the reference drug, N-acetylcysteine, were injected after modeling of ischemia for 3 days. After that, neurological symptoms, the area of cerebral infarction, and change in mitochondrial function were evaluated.

Results

It was established that use of all chromon-3-aldehyde derivatives contributed to the recovery of mitochondrial function, which was reflected in enhanced ATP-generating activity, maximum respiration level, respiratory capacity, as well as reduction in the intensity of anaerobic reactions, apoptosis, and normalization of the mitochondrial membrane potential. The most pronounced changes were noted with the use of 6-acetyl substituted chromon-3-aldehyde derivative, the administration of which decreased neurological symptoms and size of brain necrosis area.

Conclusion

The obtained data may indicate the most pronounced neurotropic effect in a number of test-objects has the 6-acetyl substituted derivative of chromon-3 aldehyde, realized by restoration of mitochondrial function, which may be the basis for further study of chromon-3-aldehyde derivatives.

Activation of CB1R-Dependent PGC-1α Is Involved in the Improved Mitochondrial Biogenesis Induced by Electroacupuncture Pretreatment

Electroacupuncture (EA) pretreatment induces cerebral ischemic tolerance; however, the mechanism remains poorly understood. This study aimed to determine the participation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α)-mediated mitochondrial biogenesis in the neuroprotection of EA and whether cannabinoid receptor 1 (CB1R) is involved in this mechanism. At 2 hours after EA pretreatment, adult male C57BL/6j mice were subjected to 60-minute right middle cerebral artery occlusion (MCAO). Mitochondrial function, the level of mitochondrial biogenesis-related proteins (nuclear transcription factor 1, NRF1; mitochondrial transcription factor A, TFAM), and mitochondrial DNA (mtDNA) were measured. A small interfering RNA (siRNA) targeting PGC-1α and the CB1R antagonists AM251 and SR141716A were given to the animals before EA pretreatment, and mitochondrial function and biogenesis were examined after MCAO. EA ameliorated the mitochondrial function, upregulated the NRF1 and TFAM expression, and increased the mtDNA levels and the volume and number of mitochondria. EA pretreatment increased the expression of PGC-1α, whereas the PGC-1α siRNA and CB1R antagonists reversed the improved neuroprotection and increased mitochondrial biogenesis induced by EA. Our results indicated that EA pretreatment protects the mitochondria and promotes mitochondrial biogenesis by activating CB1R-dependent PGC-1α, which provides a novel mechanism for EA pretreatment-induced ischemic tolerance.