[Show abstract][Hide abstract] ABSTRACT: Whole transcriptome studies have used 3'-biased expression microarrays to study genes regulated in the blood of stroke patients. However, alternatively spliced messenger RNA isoforms have not been investigated for ischemic stroke or intracerebral hemorrhage (ICH) in animals or humans. Alternative splicing is the mechanism whereby different combinations of exons of a single gene produce distinct mRNA and protein isoforms. Here, we used RNA sequencing (RNA-seq) to determine if alternative splicing differs for ICH and cardioembolic, large vessel and lacunar causes of ischemic stroke compared to controls. RNA libraries from 20 whole blood samples were sequenced to 200 M 2 × 100 bp reads using Illumina sequencing-by-synthesis technology. Differential alternative splicing was assessed using one-way analysis of variance (ANOVA), and differential exon usage was calculated. Four hundred twelve genes displayed differential alternative splicing among the groups (false discovery rate, FDR; p < 0.05). They were involved in cellular immune response, cell death, and cell survival pathways. Distinct expression signatures based on usage of 308 exons (292 genes) differentiated the groups (p < 0.0005; fold change >|1.2|). This pilot study demonstrates that alternatively spliced genes from whole blood differ in ICH compared to ischemic stroke and differ between different ischemic stroke etiologies. These results require validation in a separate cohort.
Translational Stroke Research 05/2015; 6(4). DOI:10.1007/s12975-015-0407-9 · 2.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Neutrophils have key roles in ischemic brain injury, thrombosis, and atherosclerosis. As such, neutrophils are of great interest as targets to treat and prevent ischemic stroke. After stroke, neutrophils respond rapidly promoting blood-brain barrier disruption, cerebral edema, and brain injury. A surge of neutrophil-derived reactive oxygen species, proteases, and cytokines are released as neutrophils interact with cerebral endothelium. Neutrophils also are linked to the major processes that cause ischemic stroke, thrombosis, and atherosclerosis. Thrombosis is promoted through interactions with platelets, clotting factors, and release of prothrombotic molecules. In atherosclerosis, neutrophils promote plaque formation and rupture by generating oxidized-low density lipoprotein, enhancing monocyte infiltration, and degrading the fibrous cap. In experimental studies targeting neutrophils can improve stroke. However, early human studies have been met with challenges, and suggest that selective targeting of neutrophils may be required. Several properties of neutrophil are beneficial and thus may important to preserve in patients with stroke including antimicrobial, antiinflammatory, and neuroprotective functions.Journal of Cerebral Blood Flow & Metabolism advance online publication, 25 March 2015; doi:10.1038/jcbfm.2015.45.
Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 03/2015; 35(6). DOI:10.1038/jcbfm.2015.45 · 5.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ischemia, white matter injury, and Alzheimer's disease (AD) pathologies often co-exist in aging brain. How one condition predisposes to, interacts with, or perhaps causes the others remains unclear.
To better understand the link between ischemia, white matter injury, and AD, adult rats were administered lipopolysaccharide (LPS) to serve as an inflammatory stimulus, and 24 h later subjected to 20-min focal cerebral ischemia (IS) followed by 30-min hypoxia (H).
Myelin and axonal damage, as well as amyloid-β (Aβ) and amyloid-β protein precursor (AβPP) deposition were examined by western blot and immunocytochemistry following LPS/IS/H. Findings were compared to the 5XFAD mouse AD brain.
Myelin/axonal injury was observed bilaterally in cortex following LPS/IS/H, along with an increase in IL-1, granzyme B, and LPS. AβPP deposition was present in ischemic striatum in regions of myelin loss. Aβ1-42 and AβPP were deposited in small foci in ischemic cortex that co-localized with myelin aggregates. In the 5XFAD mouse AD model, cortical amyloid plaques also co-localized with myelin aggregates.
LPS/IS/H produce myelin injury and plaque-like aggregates of myelin. AβPP and Aβ co-localize with these myelin aggregates.
[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to show that myelin and axons in cortical gray matter are damaged in Alzheimer's disease (AD) brain. Superior temporal gyrus gray matter of AD patients (9 male, 14 female) was compared to cognitively normal controls (8 male, 7 female). Myelin basic protein (MBP) and a degraded myelin basic protein complex (dMBP) were quantified by Western blot. Brain sections were immunostained for MBP, dMBP, axonal neurofilament protein (NF), autophagy marker microtubule-associated proteins 1A/B light chain 3B precursor (LC3B), amyloid-β protein precursor (AβPP), and amyloid markers amyloid β1-42 (Aβ1-42) and FSB. Co-immunoprecipitation and mass spectroscopy evaluated interaction of AβPP/Aβ1-42 with MBP/dMBP. Evidence of axonal injury in AD cortex included appearance of AβPP in NF stained axons, and NF at margins of amyloid plaques. Evidence of myelin injury in AD cortex included (1) increased dMBP in AD gray matter compared to control (p < 0.001); (2) dMBP in AD neurons; and (3) increased LC3B that co-localized with MBP. Evidence of interaction of AβPP/Aβ1-42 with myelin or axonal components included (1) greater binding of dMBP with AβPP in AD brain; (2) MBP at the margins of amyloid plaques; (3) dMBP co-localized with Aβ1-42 in the core of amyloid plaques in AD brains; and (4) interactions between Aβ1-42 and MBP/dMBP by co-immunoprecipitation and mass spectrometry. We conclude that damaged axons may be a source of AβPP. dMBP, MBP, and NF associate with amyloid plaques and dMBP associates with AβPP and Aβ1-42. These molecules could be involved in formation of amyloid plaques.
[Show abstract][Hide abstract] ABSTRACT: Aims
Epidemiological studies suggest that sex has a role in the pathogenesis of cardioembolic stroke. Since stroke is a vascular disease, identifying sexually dimorphic gene expression changes in blood leukocytes can inform on sex-specific risk factors, response and outcome biology. We aimed to examine the sexually dimorphic immune response following cardioembolic stroke by studying the differential gene expression in peripheral white blood cells.
Methods and Results
Blood samples from patients with cardioembolic stroke were obtained at ≤3 hours (prior to treatment), 5 hours and 24 hours (after treatment) after stroke onset (n = 23; 69 samples) and compared with vascular risk factor controls without symptomatic vascular diseases (n = 23, 23 samples) (ANCOVA, false discovery rate p≤0.05, |fold change| ≥1.2). mRNA levels were measured on whole-genome Affymetrix microarrays. There were more up-regulated than down-regulated genes in both sexes, and females had more differentially expressed genes than males following cardioembolic stroke. Female gene expression was associated with cell death and survival, cell-cell signaling and inflammation. Male gene expression was associated with cellular assembly, organization and compromise. Immune response pathways were over represented at ≤3, 5 and 24 h after stroke in female subjects but only at 24 h in males. Neutrophil-specific genes were differentially expressed at 3, 5 and 24 h in females but only at 5 h and 24 h in males.
There are sexually dimorphic immune cell expression profiles following cardioembolic stroke. Future studies are needed to confirm the findings using qRT-PCR in an independent cohort, to determine how they relate to risk and outcome, and to compare to other causes of ischemic stroke.
PLoS ONE 07/2014; 9(7):e102550. DOI:10.1371/journal.pone.0102550 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
microRNA (miRNA) are important regulators of gene expression. In patients with ischemic stroke we have previously shown that differences in immune cell gene expression are present. In this study we sought to determine the miRNA that are differentially expressed in peripheral blood cells of patients with acute ischemic stroke and thus may regulate immune cell gene expression.
miRNA from peripheral blood cells of forty-eight patients with ischemic stroke and vascular risk factor controls were compared. Differentially expressed miRNA in patients with ischemic stroke were determined by microarray with qRT-PCR confirmation. The gene targets and pathways associated with ischemic stroke that may be regulated by the identified miRNA were characterized.
In patients with acute ischemic stroke, miR-122, miR-148a, let-7i, miR-19a, miR-320d, miR-4429 were decreased and miR-363, miR-487b were increased compared to vascular risk factor controls. These miRNA are predicted to regulate several genes in pathways previously identified by gene expression analyses, including toll-like receptor signaling, NF-κβ signaling, leukocyte extravasation signaling, and the prothrombin activation pathway.
Several miRNA are differentially expressed in blood cells of patients with acute ischemic stroke. These miRNA may regulate leukocyte gene expression in ischemic stroke including pathways involved in immune activation, leukocyte extravasation and thrombosis.
PLoS ONE 06/2014; 9(6):e99283. DOI:10.1371/journal.pone.0099283 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Defining the RNA transcriptome in Alzheimer Disease (AD) will help understand the disease mechanisms and provide biomarkers. Though the AD blood transcriptome has been studied, effects of white matter hyperintensities (WMH) were not considered. This study investigated the AD blood transcriptome and accounted for WMH.
RNA from whole blood was processed on whole-genome microarrays.
A total of 293 probe sets were differentially expressed in AD versus controls, 5 of which were significant for WMH status. The 288 AD-specific probe sets classified subjects with 87.5% sensitivity and 90.5% specificity. They represented 188 genes of which 29 have been reported in prior AD blood and 89 in AD brain studies. Regulated blood genes included MMP9, MME (Neprilysin), TGFβ1, CA4, OCLN, ATM, TGM3, IGFR2, NOV, RNF213, BMX, LRRN1, CAMK2G, INSR, CTSD, SORCS1, SORL1, and TANC2.
RNA expression is altered in AD blood irrespective of WMH status. Some genes are shared with AD brain.
[Show abstract][Hide abstract] ABSTRACT: Objective:
Myelin disruption is an important feature of Alzheimer's disease (AD) that contributes to impairment of neuronal circuitry and cognition. In this study we characterize myelin degradation in the brains of patients with Alzheimer's disease compared with normal aged controls.
Myelin from patients with AD (n=13) was compared to matched controls (n=6). Myelin degradation was examined by immunohistochemistry in frontal white matter (WM) for intact myelin basic protein (MBP), degraded MBP, the presence of myelin lipid and for PAS staining. The relationship of myelin degradation and axonal injury was also assessed.
Brains from patients with AD had significant loss of intact MBP, and an increase in degraded MBP in periventricular WM adjacent to a denuded ependymal layer. In regions of myelin degradation, vesicles were identified that stained positive for degraded MBP, myelin lipid, and neurofilament but not for intact MBP. Most vesicles stained for PAS, a corpora amylacea marker. The vesicles were significantly more abundant in the periventricular WM of AD patients compared to controls (44.5 ± 11.0 versus 1.7 ± 1.1, p=0.02).
In AD patients degraded MBP is associated in part with vesicles particularly in periventricular WM that is adjacent to areas of ependymal injury.
Current Alzheimer research 01/2014; 11(3). DOI:10.2174/1567205011666140131120922 · 3.89 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Traumatic brain injury (TBI) is often associated with intracerebral and intraventricular hemorrhage. Thrombin is a neurotoxin generated at bleeding sites following TBI, and can lead to cell death and subsequent cognitive dysfunction via activation of Src family kinases (SFKs). We hypothesize that inhibiting SFKs can protect hippocampal neurons and improve cognitive memory function following TBI. To test these hypotheses we show that moderate lateral fluid percussion (LFP) TBI in adult rats produces bleeding into the cerebrospinal fluid (CSF) in both lateral ventricles, which elevates oxyhemoglobin and thrombin levels in CSF, activates the SFK family member Fyn, and increases Rho-kinase 1(ROCK1) expression. Systemic administration of the SFK inhibitor, PP2, immediately following moderate TBI blocks ROCK1 expression, protects hippocampal CA2-3 neurons, and improves spatial memory function. These data suggest the possibility that inhibiting SFKs following TBI might improve clinical outcomes.
Journal of neurotrauma 01/2014; 31(14). DOI:10.1089/neu.2013.3250 · 3.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hemorrhagic transformation (HT) is a common complication of ischemic stroke that is exacerbated by thrombolytic therapy. Methods to better prevent, predict, and treat HT are needed. In this review, we summarize studies of HT in both animals and humans. We propose that early HT (<18 to 24 hours after stroke onset) relates to leukocyte-derived matrix metalloproteinase-9 (MMP-9) and brain-derived MMP-2 that damage the neurovascular unit and promote blood-brain barrier (BBB) disruption. This contrasts to delayed HT (>18 to 24 hours after stroke) that relates to ischemia activation of brain proteases (MMP-2, MMP-3, MMP-9, and endogenous tissue plasminogen activator), neuroinflammation, and factors that promote vascular remodeling (vascular endothelial growth factor and high-moblity-group-box-1). Processes that mediate BBB repair and reduce HT risk are discussed, including transforming growth factor beta signaling in monocytes, Src kinase signaling, MMP inhibitors, and inhibitors of reactive oxygen species. Finally, clinical features associated with HT in patients with stroke are reviewed, including approaches to predict HT by clinical factors, brain imaging, and blood biomarkers. Though remarkable advances in our understanding of HT have been made, additional efforts are needed to translate these discoveries to the clinic and reduce the impact of HT on patients with ischemic stroke.Journal of Cerebral Blood Flow & Metabolism advance online publication, 27 November 2013; doi:10.1038/jcbfm.2013.203.
Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 11/2013; 34(2). DOI:10.1038/jcbfm.2013.203 · 5.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
Hemorrhagic transformation (HT) is a major complication of ischemic stroke that worsens outcomes and increases mortality. Disruption of the blood-brain barrier is a central feature of HT pathogenesis, and leukocytes may contribute to this process. We sought to determine whether ischemic strokes that develop HT have differences in RNA expression in blood within 3 hours of stroke onset prior to treatment with thrombolytic therapy.
Stroke patient blood samples were obtained prior to treatment with thrombolysis, and leukocyte RNA was assessed by microarray analysis. Strokes that developed HT (n = 11) were compared to strokes without HT (n = 33) and controls (n = 14). Genes were identified (corrected p < 0.05, fold change ≥|1.2|), and functional analysis was performed. RNA prediction of HT in stroke was evaluated using cross-validation, and in a second stroke cohort (n = 52).
Ischemic strokes that developed HT had differential expression of 29 genes in circulating leukocytes prior to treatment with thrombolytic therapy. A panel of 6 genes could predict strokes that later developed HT with 80% sensitivity and 70.2% specificity. Key pathways involved in HT of human stroke are described, including amphiregulin, a growth factor that regulates matrix metalloproteinase-9; a shift in transforming growth factor-β signaling involving SMAD4, INPP5D, and IRAK3; and a disruption of coagulation factors V and VIII.
Identified genes correspond to differences in inflammation and coagulation that may predispose to HT in ischemic stroke. Given the adverse impact of HT on stroke outcomes, further evaluation of the identified genes and pathways is warranted to determine their potential as therapeutic targets to reduce HT and as markers of HT risk.
Annals of Neurology 09/2013; 74(2). DOI:10.1002/ana.23883 · 9.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The cause of ischemic stroke remains unclear, or cryptogenic, in as many as 35% of patients with stroke. Not knowing the cause of stroke restricts optimal implementation of prevention therapy and limits stroke research. We demonstrate how gene expression profiles in blood can be used in conjunction with a measure of infarct location on neuroimaging to predict a probable cause in cryptogenic stroke.
The cause of cryptogenic stroke was predicted using previously described profiles of differentially expressed genes characteristic of patients with cardioembolic, arterial, and lacunar stroke. RNA was isolated from peripheral blood of 131 cryptogenic strokes and compared with profiles derived from 149 strokes of known cause. Each sample was run on Affymetrix U133 Plus 2.0 microarrays. Cause of cryptogenic stroke was predicted using gene expression in blood and infarct location.
Cryptogenic strokes were predicted to be 58% cardioembolic, 18% arterial, 12% lacunar, and 12% unclear etiology. Cryptogenic stroke of predicted cardioembolic etiology had more prior myocardial infarction and higher CHA(2)DS(2)-VASc scores compared with stroke of predicted arterial etiology. Predicted lacunar strokes had higher systolic and diastolic blood pressures and lower National Institutes of Health Stroke Scale compared with predicted arterial and cardioembolic strokes. Cryptogenic strokes of unclear predicted etiology were less likely to have a prior transient ischemic attack or ischemic stroke.
Gene expression in conjunction with a measure of infarct location can predict a probable cause in cryptogenic strokes. Predicted groups require further evaluation to determine whether relevant clinical, imaging, or therapeutic differences exist for each group.
[Show abstract][Hide abstract] ABSTRACT: Sex is suggested to be an important determinant of ischemic stroke risk factors, etiology, and outcome. However, the basis for this remains unclear. The Y chromosome is unique in males. Genes expressed in males on the Y chromosome that are associated with stroke may be important genetic contributors to the unique features of males with ischemic stroke, which would be helpful for explaining sex differences observed between men and women.
We compared Y chromosome gene expression in males with ischemic stroke and male controls.
Blood samples were obtained from 40 male patients ≤3, 5, and 24 hours after ischemic stroke and from 41 male controls (July 2003-April 2007). RNA was isolated from blood and was processed using Affymetrix Human U133 Plus 2.0 expression arrays (Affymetrix Inc., Santa Clara, California). Y chromosome genes differentially expressed between male patients with stroke and male control subjects were identified using an ANCOVA adjusted for age and batch. A P < 0.05 and a fold change >1.2 were considered significant.
Seven genes on the Y chromosome were differentially expressed in males with ischemic stroke compared with controls. Five of these genes (VAMP7, CSF2RA, SPRY3, DHRSX, and PLCXD1) are located on pseudoautosomal regions of the human Y chromosome. The other 2 genes (EIF1AY and DDX3Y) are located on the nonrecombining region of the human Y chromosome. The identified genes were associated with immunology, RNA metabolism, vesicle fusion, and angiogenesis.
Specific genes on the Y chromosome are differentially expressed in blood after ischemic stroke. These genes provide insight into potential molecular contributors to sex differences in ischemic stroke.
Gender Medicine 02/2012; 9(2):68-75.e3. DOI:10.1016/j.genm.2012.01.005 · 2.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Deciphering whether a transient neurological event (TNE) is of ischemic or nonischemic etiology can be challenging. Ischemia of cerebral tissue elicits an immune response in stroke and transient ischemic attack (TIA). This response, as detected by RNA expressed in immune cells, could potentially distinguish ischemic from nonischemic TNE.
Analysis of 208 TIAs, ischemic strokes, controls, and TNE was performed. RNA from blood was processed on microarrays. TIAs (n=26) and ischemic strokes (n=94) were compared with controls (n=44) to identify differentially expressed genes (false discovery rate <0.05, fold change ≥1.2). Genes common to TIA and stroke were used predict ischemia in TIA diffusion-weighted imaging-positive/minor stroke (n=17), nonischemic TNE (n=13), and TNE of unclear etiology (n=14).
Seventy-four genes expressed in TIA were common to those in ischemic stroke. Functional pathways common to TIA and stroke related to activation of innate and adaptive immune systems, involving granulocytes and B cells. A prediction model using 26 of the 74 ischemia genes distinguished TIA and stroke subjects from control subjects with 89% sensitivity and specificity. In the validation cohort, 17 of 17 TIA diffusion-weighted imaging-positive/minor strokes were predicted to be ischemic, and 10 of 13 nonischemic TNE were predicted to be nonischemic. In TNE of unclear etiology, 71% were predicted to be ischemic. These subjects had higher ABCD(2) scores.
A common molecular response to ischemia in TIA and stroke was identified, relating to activation of innate and adaptive immune systems. TNE of ischemic etiology was identified based on gene profiles that may be of clinical use once validated.
[Show abstract][Hide abstract] ABSTRACT: This study examined the effects of gender on RNA expression after ischemic stroke (IS). RNA obtained from blood of IS patients (n=51; 153 samples at < or =3, 5, and 24 hours) and from matched controls (n=52) were processed on Affymetrix microarrays. Analyses of covariance for stroke versus control samples were performed separately for both genders and the regulated genes for females compared with males. In all, 242, 227, and 338 male-specific genes were regulated at < or =3, 5, and 24 hours after IS, respectively, of which 59 were regulated at all time points. Overall, 774, 3,437, and 571 female-specific stroke genes were regulated at < or =3, 5, and 24 hours, respectively, of which 152 were regulated at all time points. Male-specific stroke genes were associated with integrin, integrin-liked kinase, actin, tight junction, Wnt/β-catenin, RhoA, fibroblast growth factors (FGF), granzyme, and tumor necrosis factor receptor (TNFR)2 signaling. Female-specific stroke genes were associated with p53, high-mobility group box-1, hypoxia inducible factor (HIF)1α, interleukin (IL)1, IL6, IL12, IL18, acute-phase response, T-helper, macrophage, and estrogen signaling. Cell death signaling was overrepresented in both genders, although the molecules and pathways differed. Gender affects gene expression in the blood of IS patients, which likely implies gender differences in immune, inflammatory, and cell death responses to stroke.
Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 12/2011; 32(5):780-91. DOI:10.1038/jcbfm.2011.179 · 5.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Differences in ischemic stroke between men and women have been mainly attributed to hormonal effects. However, sex differences in immune response to ischemia may exist. We hypothesized that differential expression of X-chromosome genes in blood immune cells contribute to differences between men and women with ischemic stroke.
RNA levels of 683 X-chromosome genes were measured on Affymetrix U133 Plus2.0 microarrays. Blood samples from patients with ischemic stroke were obtained at ≤ 3 hours, 5 hours, and 24 hours (n=61; 183 samples) after onset and compared with control subjects without symptomatic vascular diseases (n=109). Sex difference in X-chromosome gene expression was determined using analysis of covariance (false discovery rate ≤ 0.05, fold change ≥ 1.2).
At ≤ 3, 5, and 24 hours after stroke, there were 37, 140, and 61 X-chromosome genes, respectively, that changed in women; and 23, 18, and 31 X-chromosome genes that changed in men. Female-specific genes were associated with post-translational modification, small-molecule biochemistry, and cell-cell signaling. Male-specific genes were associated with cellular movement, development, cell-trafficking, and cell death. Altered sex specific X-chromosome gene expression occurred in 2 genes known to be associated with human stroke, including galactosidase A and IDS, mutations of which result in Fabry disease and Hunter syndrome, respectively.
There are differences in X-chromosome gene expression between men and women with ischemic stroke. Future studies are needed to decipher whether these differences are associated with sexually dimorphic immune response, repair or other mechanisms after stroke, or whether some of them represent risk determinants.
[Show abstract][Hide abstract] ABSTRACT: Determining which small deep infarcts (SDIs) are of lacunar, arterial, or cardioembolic etiology is challenging, but important in delivering optimal stroke prevention therapy. We sought to distinguish lacunar from nonlacunar causes of SDIs using a gene expression profile.
A total of 184 ischemic strokes were analyzed. Lacunar stroke was defined as a lacunar syndrome with infarction <15mm in a region supplied by penetrating arteries. RNA from blood was processed on whole genome microarrays. Genes differentially expressed between lacunar (n = 30) and nonlacunar strokes (n = 86) were identified (false discovery rate ≤ 0.05, fold change >|1.5|) and used to develop a prediction model. The model was evaluated by cross-validation and in a second test cohort (n = 36). The etiology of SDIs of unclear cause (SDIs ≥ 15mm or SDIs with potential embolic source) (n = 32) was predicted using the derived model.
A 41-gene profile discriminated lacunar from nonlacunar stroke with >90% sensitivity and specificity. Of the 32 SDIs of unclear cause, 15 were predicted to be lacunar, and 17 were predicted to be nonlacunar. The identified profile represents differences in immune response between lacunar and nonlacunar stroke.
Profiles of differentially expressed genes can distinguish lacunar from nonlacunar stroke. SDIs of unclear cause were frequently predicted to be of nonlacunar etiology, suggesting that comprehensive workup of SDIs is important to identify potential cardioembolic and arterial causes. Further study is required to evaluate the gene profile in an independent cohort and determine the clinical and treatment implications of SDIs of predicted nonlacunar etiology.
Annals of Neurology 09/2011; 70(3):477-85. DOI:10.1002/ana.22497 · 9.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Whole genome expression microarrays can be used to study gene expression in blood, which comes in part from leukocytes, immature platelets, and red blood cells. Since these cells are important in the pathogenesis of stroke, RNA provides an index of these cellular responses to stroke. Our studies in rats have shown specific gene expression changes 24 hours after ischemic stroke, hemorrhage, status epilepticus, hypoxia, hypoglycemia, global ischemia, and following brief focal ischemia that simulated transient ischemic attacks in humans. Human studies show gene expression changes following ischemic stroke. These gene profiles predict a second cohort with >90% sensitivity and specificity. Gene profiles for ischemic stroke caused by large-vessel atherosclerosis and cardioembolism have been described that predict a second cohort with >85% sensitivity and specificity. Atherosclerotic genes were associated with clotting, platelets, and monocytes, and cardioembolic genes were associated with inflammation, infection, and neutrophils. These gene profiles predicted the cause of stroke in 58% of cryptogenic patients. These studies will provide diagnostic, prognostic, and therapeutic markers, and will advance our understanding of stroke in humans. New techniques to measure all coding and noncoding RNAs along with alternatively spliced transcripts will markedly advance molecular studies of human stroke.
Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 07/2011; 31(7):1513-31. DOI:10.1038/jcbfm.2011.45 · 5.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A blood test to detect stroke and its causes would be particularly useful in babies, young children, and patients in intensive care units and for emergencies when imaging is difficult to obtain or is unavailable. Whole genome microarrays were used to show specific gene expression profiles in rats 24 hours after ischemic and hemorrhagic stroke, hypoxia, and hypoglycemia. These proof-of-principle studies revealed that groups of genes (called gene profiles) can distinguish ischemic stroke patients from controls within 3 to 24 hours after the strokes. In addition, gene expression profiles have been developed that distinguish stroke due to large-vessel atherosclerosis from cardioembolic stroke. These profiles will be useful for predicting the causes of cryptogenic stroke. The results in adults suggest that similar diagnostic tools could be developed for children.
[Show abstract][Hide abstract] ABSTRACT: Tourette syndrome (TS) is a complex childhood neurodevelopmental disorder characterized by motor and vocal tics. Recently, altered numbers of GABAergic-parvalbumin (PV) and cholinergic interneurons were observed in the basal ganglia of individuals with TS. Thus, we postulated that gamma-amino butyric acid (GABA)- and acetylcholine (ACh)-related genes might be associated with the pathophysiology of TS. Total RNA isolated from whole blood of 26 un-medicated TS subjects and 23 healthy controls (HC) was processed on Affymetrix Human Exon 1.0 ST arrays. Data were analyzed to identify genes whose expression correlated with tic severity in TS, and to identify genes differentially spliced in TS compared to HC subjects. Many genes (3627) correlated with tic severity in TS (p < 0.05) among which GABA- (p = 2.1 × 10⁻³) and ACh- (p = 4.25 × 10⁻⁸) related genes were significantly over-represented. Moreover, several GABA and ACh-related genes were predicted to be alternatively spliced in TS compared to HC including GABA receptors GABRA4 and GABRG1, the nicotinic ACh receptor CHRNA4 and cholinergic differentiation factor (CDF). This pilot study suggests that at least some of these GABA- and ACh-related genes observed in blood that correlate with tics or are alternatively spliced are involved in the pathophysiology of TS and tics.
Brain research 03/2011; 1381:228-36. DOI:10.1016/j.brainres.2011.01.026 · 2.84 Impact Factor