sphingosine-1-phosphate and Infarction--Middle-Cerebral-Artery

Sphingosine 1-phosphate (S1P) is an important lipid biomolecule that exerts pleiotropic cellular actions as it binds to and activates its five G-protein-coupled receptors, S1P

Topics: Animals; Brain Damage, Chronic; Brain Ischemia; Clinical Trials as Topic; Disease Models, Animal; Drug Evaluation, Preclinical; Fingolimod Hydrochloride; Humans; Infarction, Middle Cerebral Artery; Inflammation; Ischemic Stroke; Lysophospholipids; Neovascularization, Physiologic; Nerve Tissue Proteins; Neuroprotective Agents; Phosphotransferases (Alcohol Group Acceptor); Rats; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors

Sphingosine 1-phosphates (S1Ps) are bioactive lipids that mediate a diverse range of effects through the activation of cognate receptors, S1P

Topics: Aldehyde-Lyases; Alzheimer Disease; Animals; Cerebrovascular Disorders; Clinical Trials as Topic; Dementia, Vascular; Drug Delivery Systems; Drug Evaluation, Preclinical; Fingolimod Hydrochloride; Humans; Infarction, Middle Cerebral Artery; Inflammation; Ischemic Stroke; Lysophospholipids; Mice; Mice, Knockout; Neurodegenerative Diseases; Phosphotransferases (Alcohol Group Acceptor); Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors

Cardiovascular diseases like stroke cause changes to sphingolipid mediators like sphingosine 1-phosphate (S1P) or its ceramide analogs, which bear the potential to either alleviate or exacerbate the neurological damage. Therefore, the precise identification of alterations within the sphingolipidome during ischemic stroke (IS) and hemorrhagic transformation (HT) harbors a putative therapeutic potential to orchestrate local and systemic immunomodulatory processes. Due to the scarcity of research in this field, we aimed to characterize the sphingolipidome in IS and HT.. C57BL/6 mice underwent middle cerebral artery occlusion (MCAO) and specimens of the peri-infarct tissue were taken for sphingolipid profiling.. Ischemic stroke resulted in reduced S1P whilst ceramides were elevated six hours post ischemia onset. However, these differences were nearly revoked at 24 hours post ischemia onset. Moreover, the topmost S1P and ceramide levels were linked to the presence of HT after MCAO. In this study we show the characterization of the sphingolipidomic landscape of the peri-infarct tissue after ischemic stroke and HT. Especially, highest values of S1P, C 18 lactosylceramide, C 18 glucosylceramide, and C 24:1 ceramide were nearly entirely expressed by mice with HT.. Our results warrant further investigations into the immunomodulatory consequences of altered sphingolipid species for the development of HT after IS.

Topics: Animals; Brain Ischemia; Ceramides; Disease Models, Animal; Infarction, Middle Cerebral Artery; Ischemic Stroke; Mice; Mice, Inbred C57BL; Sphingolipids; Stroke

Cerebrovascular function is critical for brain health, and endogenous vascular protective pathways may provide therapeutic targets for neurological disorders. S1P (Sphingosine 1-phosphate) signaling coordinates vascular functions in other organs, and S1P. To address roles and mechanisms of engagement of endothelial cell S1P. Using spatial modulation of S1P provision and signaling, we demonstrate a critical vascular protective role for endothelial S1P. This study provides genetic evidence to support a pivotal role for the endothelium in maintaining perfusion and microvascular patency in the ischemic penumbra that is coordinated by S1P signaling and can be harnessed for neuroprotection with blood-brain barrier-penetrating S1P

Topics: Animals; Blood-Brain Barrier; Cerebral Arteries; Cerebrovascular Circulation; Disease Models, Animal; Endothelial Cells; Female; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Ischemic Stroke; Lysophospholipids; Male; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Microcirculation; Neuroprotective Agents; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; Vascular Patency

Sphingosine 1-phosphate (S1P) is a major bioactive lipid mediator in the vascular and immune system. Here, we have shown that inhibition of S1P signaling prevents blood-brain barrier (BBB) dysfunction after ischemia both in vitro and in vivo. In the in vitro BBB models, oxygen-glucose deprivation and reoxygenation (OGD/R) enhanced the expression of an S1P synthesizing enzyme (Sphk1) and S1P transporters (Abca1, Spns2), increasing S1P in culture media. Inhibitors of Sphk1 (SKI-II) or Abca1 (probucol) attenuated the decrease in transendothelial electrical resistance and the increase in permeability caused by OGD/R. In the middle cerebral artery occlusion and reperfusion (MCAO/R) model of mice, probucol administration after MCAO operation reduced the infarction area and vascular leakage, preserving the integrity of tight junction proteins. Furthermore, MCAO/R caused activation of STAT3, a downstream mediator of S1P signaling, which was suppressed by postoperative probucol administration. Accordingly, S1P activated STAT3, both in cultured vascular endothelial cells and pericytes, and STAT3 signaling inhibitor (Stattic) protected BBB dysfunction in OGD/R-treated in vitro BBB models. These results suggest that inhibition of S1P signaling is a strategy to treat BBB impairment after cerebral ischemia and highlight the potential alternative use of probucol, a classical anti-hyperlipidemic drug, for emergency treatment of stroke.

Topics: Animals; Biological Transport; Blood-Brain Barrier; Brain Ischemia; Endothelial Cells; Glucose; Infarction, Middle Cerebral Artery; Lysophospholipids; Mice; Pericytes; Rats, Wistar; Reperfusion Injury; Sphingosine; Stroke

There is thought to be a strong relationship between sphingosine-1-phosphate (S1P) signaling and pathophysiolosy of cerebral ischemia. We examined the change of expression and distribution of S1P receptors (S1PRs) and sphingosine kinases (SphKs) after cerebral ischemia in male C57BL6/J mice using immunohistochemical analysis at 1, 5, 14, and 28 days after 30 min of transient middle cerebral artery occlusion (tMCAO). S1PR1, 3, and 5 were transiently induced in the cells, which were morphologically similar to neurons in the peri-infarct lesion with a peak seen at 1 day after tMCAO (p < 0.01 vs. sham control). S1PR2 appeared in the inner layer of vessels in the ischemic core (p < 0.01 vs. sham control) and the peri-infarct lesion (p < 0.01 vs. sham control) at the acute phase after tMCAO. However, SphK1 was strongly induced at 1 and 5 days after tMCAO (p < 0.01 vs. sham control) in the peri-infarct lesion, whereas SphK2 expression did not change. Western blot analysis at 1 and 5 days after 30 min of tMCAO revealed that the expression of S1PRs were transiently enhanced at the acute phase, which was consistent with the immunohistochemical results. Double immunofluorescent analysis revealed S1PR2/NG2- and S1PR2/CD31-, S1PR3/CD31-, and S1PR5/CD31-double positive cells in the peri-infarct lesion 1 day after tMCAO. The present results suggest that S1PRs and SphK1 may be important therapeutic targets for rescuing the peri-infarct lesion.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Infarction, Middle Cerebral Artery; Lysophospholipids; Male; Mice; Mice, Inbred C57BL; Neurons; Phosphotransferases (Alcohol Group Acceptor); Receptors, Lysosphingolipid; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; Transcriptional Activation

Sphingolipids (SPLs) have been proposed as potential therapeutic targets for strokes, but no reports have ever profiled the changes of the entire range of SPLs after a stroke. This study applied sphingolipidomic methods to investigate the temporal and individual changes in the sphingolipidome including the effect of atorvastatin after ischemic brain injury. We conducted sphingolipidomic profiling of mouse brain tissue by liquid chromatography-electrospray ionization tandem mass spectrometry at 3 h and 24 h after 1 h of middle cerebral artery occlusion (MCAO), and SPL levels were compared with those of the

Topics: Animals; Atorvastatin; Brain; Brain Injuries; Brain Ischemia; Ceramides; Chromatography, High Pressure Liquid; Disease Models, Animal; Humans; Infarction, Middle Cerebral Artery; Lipidomics; Lysophospholipids; Mice; Sphingolipids; Sphingosine; Stroke; Tandem Mass Spectrometry

Microglial activation is one of the causative factors of neuroinflammation in cerebral ischemia/reperfusion (IR). Sphingosine kinase 1 (Sphk1), a key enzyme responsible for phosphorylating sphingosine into sphingosine-1-phosphate (S1P), plays an important role in the regulation of proinflammatory cytokines in activated microglia. Recent research demonstrated that S1P increased IL-17A-secretion and then worsened CNS (central nervous system) inflammation. Thus, in the present study, we sought to use microglial cells as the object of study to discuss the molecular mechanisms in Sphk1/S1P-regulated IL-17A-secretion in IR.. We used immunofluorescence and confocal microscopy to detect whether Sphk1 is expressed in microglia after cerebral IR or oxygen-glucose deprivation (OGDR). Western blot analysis was used to estimate the total Sphk1 protein level at different time points after OGDR. To detect cytokine secretion in microglial supernatants in response to OGDR, we measured the concentration of IL-17A in the culture supernatants using an enzyme-linked immunosorbent assay (ELISA). To evaluate whether microglia subjected to OGDR exhibited neuronal injury, we used a commercially available terminal transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) kit to detect apoptotic neurons.. Sphk1 was expressed in microglia in response to cerebral IR or OGDR at appointed time. Pre-injection with PF-543, an inhibitor of Sphk1, before IR clearly reduced the expression of Sphk1 in microglia relative to brain IR alone. The number of TUNEL-positive neurons was also decreased in the PF-543-pretreated animals before IR compared to the animals with IR alone. When S1P was administered in OGDR microglia, IL-17A expression and neuronal apoptosis were increased compared to OGDR alone and the administration of S1P alone. ELISA further confirmed the above results. Moreover, the inhibition of Sphk1 by siRNA reduced IL-17A production and relieved neuronal apoptosis in OGDR microglia.. These results indicated that Sphk1/S1P regulates the expression of IL-17A in activated microglia, inducing neuronal apoptosis in cerebral ischemia/reperfusion. The microglial Sphk1/S1P pathway may thus be a potential therapeutic target to control neuroinflammation in brain IR.

Topics: Animals; Apoptosis; Brain; Brain Ischemia; Cells, Cultured; Glucose; Hypoxia, Brain; Infarction, Middle Cerebral Artery; Interleukin-17; Lysophospholipids; Male; Methanol; Microglia; Neurons; Phosphotransferases (Alcohol Group Acceptor); Pyrrolidines; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Small Interfering; Sphingosine; Sulfones

The importance of bioactive lipid signaling under physiological and pathophysiological conditions is progressively becoming recognized. The disparate distribution of sphingosine kinase (SphK) isoform activity in normal and ischemic brain, particularly the large excess of SphK2 in cerebral microvascular endothelial cells, suggests potentially unique cell- and region-specific signaling by its product sphingosine-1-phosphate. The present study sought to test the isoform-specific role of SphK as a trigger of hypoxic preconditioning (HPC)-induced ischemic tolerance.. Temporal changes in microvascular SphK activity and expression were measured after HPC. The SphK inhibitor dimethylsphingosine or sphingosine analog FTY720 was administered to adult male Swiss-Webster ND4 mice before HPC. Two days later, mice underwent a 60-minute transient middle cerebral artery occlusion and at 24 hours of reperfusion, infarct volume, neurological deficit, and hemispheric edema were measured.. HPC rapidly increased microvascular SphK2 protein expression (1.7+/-0.2-fold) and activity (2.5+/-0.6-fold), peaking at 2 hours, whereas SphK1 was unchanged. SphK inhibition during HPC abrogated reductions in infarct volume, neurological deficit, and ipsilateral edema in HPC-treated mice. FTY720 given 48 hours before stroke also promoted ischemic tolerance; when combined with HPC, even greater (and dimethylsphingosine-reversible) protection was noted.. These findings indicate hypoxia-sensitive increases in SphK2 activity may serve as a proximal trigger that ultimately leads to sphingosine-1-phosphate-mediated alterations in gene expression that promote the ischemia-tolerant phenotype. Thus, components of this bioactive lipid signaling pathway may be suitable therapeutic targets for protecting the neurovascular unit in stroke.

Topics: Animals; Arterioles; Brain Edema; Cerebral Arteries; Cerebrovascular Circulation; Disease Models, Animal; Fingolimod Hydrochloride; Hypoxia-Ischemia, Brain; Immunosuppressive Agents; Infarction, Middle Cerebral Artery; Ischemic Preconditioning; Lysophospholipids; Male; Mice; Microcirculation; Phosphotransferases (Alcohol Group Acceptor); Propylene Glycols; Reperfusion Injury; RNA, Messenger; Sphingosine

Sphingosine-1-phosphate (S1P) is a lipid mediator that exerts multiple cellular functions through activation of a subfamily of G-protein-coupled receptors. Although there is evidence that S1P plays a role in the developing and adult CNS, little is known about the ability of brain parenchyma to synthesize this lipid. We have therefore analyzed the brain distribution of the enzymatic activity of the S1P synthesizing enzyme, sphingosine kinase (SPHK) [EC:2.7.1.91], as well as mRNA distribution for one of the two isoforms of this enzyme, sphingosine kinase 2. SPHK activity, measured by the conversion of [(3)H]sphingosine to [(3)H]S1P, is highest in cerebellum, followed by cortex and brainstem. Lowest activities were found in striatum and hippocampus. Sensitivity to 0.1% Triton-X suggests that this activity is accounted for by SPHK2. RT-PCR and in situ hybridization studies show that mRNA for this isoform has a distribution similar to that of SPHK activity. In vivo and in vitro ischemia increase SPHK activity and SPHK2 mRNA levels. These results indicate that SPHK2 is the predominant S1P-synthesizing isoform in normal brain parenchyma. Its heterogeneous distribution, in particular laminar distribution in cortex, suggests a neuronal localization and a possible role in cortical and cerebellar functions, in normal as well as ischemic brain.

Topics: Animals; Blotting, Northern; Blotting, Western; Brain; Brain Chemistry; Cells, Cultured; Female; Glucose; Hypoxia, Brain; In Situ Hybridization; Infarction, Middle Cerebral Artery; Lysophospholipids; Male; Mice; Mice, Inbred ICR; Neuroglia; Neurons; Phosphotransferases (Alcohol Group Acceptor); Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sphingosine