Variations in the cerebrospinal fluid proteome following traumatic brain injury and subarachnoid hemorrhage

BACKGROUND

Proteomic analysis of cerebrospinal fluid (CSF) has shown great promise in identifying potential markers of injury in neurodegenerative diseases [1-13]. Here we compared CSF proteomes in healthy individuals, with patients diagnosed with traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) in order to characterize molecular biomarkers which might identify these different clinical states and describe different molecular mechanisms active in each disease state.

METHODS

Patients presenting to the Neurosurgery service at the Louisiana State University Hospital-Shreveport with an admitting diagnosis of TBI or SAH were prospectively enrolled. Patients undergoing CSF sampling for diagnostic procedures were also enrolled as controls. CSF aliquots were subjected to 2-dimensional gel electrophoresis (2D GE) and spot percentage densities analyzed. Increased or decreased spot expression (compared to controls) was defined in terms of in spot percentages, with spots showing consistent expression change across TBI or SAH specimens being followed up by Matrix-Assisted Laser Desorption/Ionization mass spectrometry (MALDI-MS). Polypeptide masses generated were matched to known standards using a search of the NCBI and/or GenPept databases for protein matches. Eight hundred fifteen separately identifiable polypeptide migration spots were identified on 2D GE gels. MALDI-MS successfully identified 13 of 22 selected 2D GE spots as recognizable polypeptides.

RESULTS

Statistically significant changes were noted in the expression of fibrinogen, carbonic anhydrase-I (CA-I), peroxiredoxin-2 (Prx-2), both α and β chains of hemoglobin, serotransferrin (Tf) and N-terminal haptoglobin (Hp) in TBI and SAH specimens, as compared to controls. The greatest mean fold change among all specimens was seen in CA-I and Hp at 30.7 and -25.7, respectively. TBI specimens trended toward greater mean increases in CA-I and Prx-2 and greater mean decreases in Hp and Tf.

CONCLUSIONS

Consistent CSF elevation of CA-I and Prx-2 with concurrent depletion of Hp and Tf may represent a useful combination of biomarkers for the prediction of severity and prognosis following brain injury.

Blood circulating microparticle species in relapsing-remitting and secondary progressive multiple sclerosis. A case-control, cross sectional study with conventional MRI and advanced iron content imaging outcomes

BACKGROUND

Although multiple sclerosis (MS) is thought to represent an excessive and inappropriate immune response to several central nervous system (CNS) autoantigens, increasing evidence also suggests that MS may also be a neurovascular inflammatory disease, characterized by endothelial activation and shedding of cell membrane microdomains known as 'microparticles' into the circulation.

OBJECTIVE

To investigate the relationships between these endothelial biomarkers and MS.

METHODS

We examined the relative abundance of CD31(+)/PECAM-1, CD51(+)CD61(+) (αV-β3) and CD54(+) (ICAM-1) bearing microparticles in sera of healthy individuals, patients with relapsing-remitting MS, and secondary-progressive MS. We also investigated the correlation among circulating levels of different microparticle species in MS with conventional MRI (T2- and T1-lesion volumes and brain atrophy), as well as novel MR modalities [assessment of iron content on susceptibility-weighted imaging (SWI)-filtered phase].

RESULTS

Differences in circulating microparticle levels were found among MS groups, and several microparticle species (CD31(+)/CD51(+)/CD61(+)/CD54(+)) were found to correlate with conventional MRI and SWI features of MS.

CONCLUSION

These results indicate that circulating microparticles' profiles in MS may support mechanistic roles for microvascular stress and injury which is an underlying contributor not only to MS initiation and progression, but also to pro-inflammatory responses.

Bioinformatics multivariate analysis determined a set of phase-specific biomarker candidates in a novel mouse model for viral myocarditis

BACKGROUND

Myocarditis is an inflammatory disease of the cardiac muscle and is mainly caused by viral infections. Viral myocarditis has been proposed to be divided into 3 phases: the acute viral phase, the subacute immune phase, and the chronic cardiac remodeling phase. Although individualized therapy should be applied depending on the phase, no clinical or experimental studies have found biomarkers that distinguish between the 3 phases. Theiler's murine encephalomyelitis virus belongs to the genus Cardiovirus and can cause myocarditis in susceptible mouse strains.

METHODS AND RESULTS

Using this novel model for viral myocarditis induced with Theiler's murine encephalomyelitis virus, we conducted multivariate analysis including echocardiography, serum troponin and viral RNA titration, and microarray to identify the biomarker candidates that can discriminate the 3 phases. Using C3H mice infected with Theiler's murine encephalomyelitis virus on 4, 7, and 60 days post infection, we conducted bioinformatics analyses, including principal component analysis and k-means clustering of microarray data, because our traditional cardiac and serum assays, including 2-way comparison of microarray data, did not lead to the identification of a single biomarker. Principal component analysis separated heart samples clearly between the groups of 4, 7, and 60 days post infection. Representative genes contributing to the separation were as follows: 4 and 7 days post infection, innate immunity-related genes, such as Irf7 and Cxcl9; 7 and 60 days post infection, acquired immunity-related genes, such as Cd3g and H2-Aa; and cardiac remodeling-related genes, such as Mmp12 and Gpnmb.

CONCLUSIONS

Sets of molecules, not single molecules, identified by unsupervised principal component analysis, were found to be useful as phase-specific biomarkers.

Abstract 039: Natural Killer T Cells Play Protective Roles in Cardiovirus-Induced Myocarditis by Inducing Anti-Viral and Regulatory Cytokines

Picornavirus infections have been known as a leading cause of viral myocarditis in humans. Theiler’s murine encephalomyelitis virus (TMEV) belongs to the genus Cardiovirus, the family Picornaviridae, and can cause myocarditis in susceptible mice. In viral myocarditis, viral replication in the heart and/or immune responses against virus as well as cardiac antigens (autoimmunity) can contribute to the pathogenesis. Natural killer T (NKT) cells can play a regulatory role in viral infections by producing anti-viral and anti-inflammatory cytokines; interferon (IFN)-γ can contribute to either viral clearance or tissue damage (immunopathology), while anti-inflammatory interleukin (IL)-10 has been suggested to regulate viral clearance or immunopathology. To determine the role of NKT cells in TMEV-induced myocarditis, we infected wild-type (WT) and NKT knockout (NKT KO, Jα18 KO) mice with TMEV. Myocarditis was monitored by echocardiography using the Vevo 770 system. During the acute (day 7) or chronic phase (day 60) of TMEV infection, cardiac pathology was evaluated by hematoxylin and eosin staining, and production of cytokines, including IFN-γ and IL-10, from spleen cells was measured by enzyme-linked immunosorbent assays. During the acute phase, the levels of left ventricular ejection fraction were significantly lower in NKT KO mice than in WT mice. Immunologically, NKT KO mice had lower levels of IFN-γ production than WT mice [IFN-γ (pg/ml): WT, 768 ± 533; NKT KO, 293 ± 190]. During the chronic phase, high intensity cardiac lesions were observed by echocardiography in NKT KO mice, but not in WT mice. Histologically, NKT KO mice developed moderate inflammation with basophilic degeneration and calcification in the heart, while WT mice had only mild inflammation in the heart. Immunologically, NKT KO mice had lower levels of IL-10 production compared with WT mice [IL-10 (pg/ml): WT, 1771 ± 381; NKT KO, 1199 ± 160]. These results suggest that NKT cells play a protective role in viral myocarditis by producing IFN-γ and IL-10, which contribute to viral clearance during the acute phase and the suppression of immunopathology during the chronic phase of disease, respectively.

Abstract 333: Chemokine and Autophagy-Related Genes in Novel In Vivo and In Vitro Models for Viral Myocarditis

Picornavirus infection is one of leading causes of myocarditis in humans. Theiler's murine encephalomyelitis virus (TMEV) belongs to the genus Cardiovirus , the family Picornaviridae . While TMEV has been used as a mouse model for multiple sclerosis (MS), TMEV can also cause myocarditis in mice. We found that the susceptibilities of mouse strains to myocarditis differed from susceptibilities to the MS model. In the heart, we detected viral replication and inflammation. However, it is unclear whether virus itself or immune cells damaged the heart. To clarify the role of direct virus infection in myocarditis we used the cardiomyocyte cell line, HL-1, which retains a differentiated cardiomyocyte phenotype and contractile activity. We infected HL-1 with TMEV and monitored cytopathic effect (CPE) and cell viability. At 8 hours post infection (hpi), HL-1 cells developed CPE with decreased contractile activities, while cell death was not obvious. We detected 54% and 93% of cell death at 12 and 24 hpi, respectively, while no cell death was observed in mock-infection. We conducted microarray analyses to compare mRNA expression patterns between TMEV and mock-infected groups, using an Affymetrix GeneChip Mouse 1.0 ST Array. Principal component analysis (PCA) for microarray data clearly separated TMEV- and mock-infected groups (PC1 proportion of variance, 59%). TMEV infection induced high expression of several interferon-associated and chemokine genes, particularly Cxcl10/IP-10 . Cxcl10 is a potent chemoattractant for activated T cells and NK cells, and its potential roles have been associated with immune cells in other myocarditis models. Our current results demonstrated that virus infection alone could induce Cxcl10 in cardiomyocytes without immune cells. We also found upregulation of autophagy-related 12 gene ( Atg12 ). In general, autophagy can contribute to eradication of intracellular pathogens including viruses. However, since induction of autophagy by picornavirus has been shown to enhance virus replication, autophagy may also play a detrimental role in TMEV-induced myocarditis. Our novel in viv o and in vitro models of myocarditis are powerful tools to dissect the role of viral and immune pathogenesis of the heart, complementing each other.

Abstract 116: Detrimental Role of Toll-Like Receptor 4 in Cardiovirus-Induced Myocarditis

Picornavirus infections have been known as a leading cause of viral myocarditis in humans. Theiler’s murine encephalomyelitis virus (TMEV) belongs to the genus Cardiovirus, the family Picornaviridae and was reported to cause inflammation in the heart in one manuscript, while its pathomechanism is unclear. In viral myocarditis, viral replication in the heart and/or immune responses against virus as well as heart-antigen (autoimmunity) can contribute to the pathogenesis. Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) that are important for recognizing pathogens as well as triggering innate immunity. Among TLRs, TLR4 has been demonstrated to play important roles in virus-mediated pathology: 1) TLR4 can contribute to viral entry in some viruses, 2) TLR4 may mediate tissue damage by anti-virus immune responses (immunopathology), 3) high levels of TLR4 expression were observed in the heart of patients with dilated cardiomyopathy following acute viral myocarditis, and 4) some viruses can bind to lipopolysaccharide (LPS), which is a TLR4 ligand. To determine the role of TLR4 in TMEV-induced myocarditis, we infected male C3H/HeJ (TLR4-deficient) and C3H/HeNtac (control TLR4+) mice with the DA strain of TMEV. We harvested the hearts and spleens on days 6 and 7 (acute phase) or days 63 and 64 (chronic phase) post-infection. Cardiac pathology was evaluated by hematoxylin and eosin staining and production of pro-inflammatory cytokines, interleukin (IL)-17A and interferon (IFN)-γ, from spleen cells was measured by an enzyme-linked immunosorbent assay (ELISA). In both mice, mild myocarditis was observed during the acute phase of TMEV infection. During the chronic phase, both mice developed severe pathology in the heart, including basophilic degeneration and calcification. However, the incidence of myocarditis was higher in control mice than TLR4-deficient mice. IL-17A and IFN-γ production was higher in control mice than in TLR4-deficient mice (control vs. TLR4-deficient mice, acute phase: IL-17A, 196 vs. 146 pg/ml; IFN-γ, 72 vs. 39 ng/ml; chronic phase: IL-17A, 290 vs. 229 pg/ml; IFN- γ, 142 vs. 88 ng/ml). These results suggest that TLR4 may be detrimental in TMEV-induced myocarditis by increasing pro-inflammatory cytokine production.

Differential cytokine responses in human and mouse lymphatic endothelial cells to cytokines in vitro

BACKGROUND

Inflammatory cytokines dysregulate microvascular function, yet how cytokines affect lymphatic endothelial cells (LEC) are unclear.

METHODS AND RESULTS

We examined effects of TNF-α, IL-1 beta, and IFN-gamma on LEC proliferation, endothelial cell adhesion molecule (ECAM) expression, capillary formation, and barrier changes in murine (SV-LEC) and human LECs (HMEC-1a).

RESULTS

All cytokines induced ICAM-1, VCAM-1, MAdCAM-1, and E-selectin in SV-LECs; TNF-α, IL-1 beta; and IFN-gamma induced ECAMs (but not MAdCAM-1) in HMEC-1a. IL-1 beta increased, while IFN-gamma and TNF-α reduced SV-LEC proliferation. While TNF-α induced, IFN-gamma decreased, and IL-1 beta did not show any effect on HMEC-1a proliferation. TNF-α, IL-1 beta, and IFN-gamma each reduced capillary formation in SV-LEC and in HMEC-1a. TNF-α and IL-1 beta reduced barrier in SV-LEC and HMEC-1a; IFN-gamma did not affect SV-LEC barrier, but enhanced HMEC-1a barrier. Inflammatory cytokines alter LEC growth, activation and barrier function in vitro and may disturb lymphatic clearance increasing tissue edema in vivo.

CONCLUSION

Therapies that maintain or restore lymphatic function (including cytokines blockade), may represent important strategies for limiting inflammation.

Role of the endothelium in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are a complex group of diseases involving alterations in mucosal immunity and gastrointestinal physiology during both initiation and progressive phases of the disease. At the core of these alterations are endothelial cells, whose continual adjustments in structure and function coordinate vascular supply, immune cell emigration, and regulation of the tissue environment. Expansion of the endothelium in IBD (angiogenesis), mediated by inflammatory growth factors, cytokines and chemokines, is a hallmark of active gut disease and is closely related to disease severity. The endothelium in newly formed or inflamed vessels differs from that in normal vessels in the production of and response to inflammatory cytokines, growth factors, and adhesion molecules, altering coagulant capacity, barrier function and blood cell recruitment in injury. This review examines the roles of the endothelium in the initiation and propagation of IBD pathology and distinctive features of the intestinal endothelium contributing to these conditions.

African-American inflammatory bowel disease in a Southern U.S. health center

Background

Inflammatory Bowel Diseases (IBD) remain significant health problems in the US and worldwide. IBD is most often associated with eastern European ancestry, and is less frequently reported in other populations of African origin e.g. African Americans ('AAs'). Whether AAs represent an important population with IBD in the US remains unclear since few studies have investigated IBD in communities with a majority representation of AA patients. The Louisiana State University Health Sciences Center in Shreveport (LSUHSC-S) is a tertiary care medical center, with a patient base composed of 58% AA and 39% Caucasian (W), ideal for evaluating racial (AA vs. W) as well and gender (M vs. F) influences on IBD.

Methods

In this retrospective study, we evaluated 951 visits to LSUHSC-S for IBD (between 2000 to 2008) using non-identified patient information based on ICD-9 medical record coding (Crohn's disease 'CD'-555.0- 555.9 and ulcerative colitis 'UC'-556.0-556.9).

Results

Overall, there were more cases of CD seen than UC. UC and CD affected similar ratios of AA and Caucasian males (M) and females (F) with a rank order of WF > WM > AAF > AAM. Interestingly, in CD, we found that annual visits per person was the highest in AA M (10.7 ± 1.7); significantly higher (* -p < 0.05) than in WM (6.3 ± 1.0). Further, in CD, the female to male (F: M) ratio in AA was significantly higher (*- p < 0.05) (1.9 ± 0.2) than in Caucasians (F:M = 1.3 ± 0.1) suggesting a female dominance in AACD; no differences were seen in UC F: M ratios.

Conclusion

Although Caucasians still represent the greatest fraction of IBD (~64%), AAs with IBD made up >1/3 (36.4%) of annual IBD cases from 2000-2008 at LSUHSC-S. Further studies on genetic and environments risks for IBD risk in AAs are needed to understand differences in presentation and progression in AAs and other 'non-traditional' populations.

Granzyme-b is involved in mediating post-ischemic neuronal death during focal cerebral ischemia in rat model

Although peripheral immune cells infiltrate ischemic infarct tissue and elicit immune injury, the role of Cytotoxic T Lymphocytes (CTLs) and the toxins they release in mediating neuronal death is not well understood. Granzyme-b (Gra-b), a serine protease found in the cytoplasmic granules of CTLs and natural killer cells, plays an important role in inducing target cell death by activating several caspases and by initiating caspase-independent pathways that contribute to target cell death. To determine if CTLs and Gra-b are involved in post-ischemic cerebral cell death; we investigated the role of CD8(+) CTLs and Gra-b in ischemic rat brain infarct after transient middle cerebral artery occlusion (tMCAO) and in sham-operated animals. We observed that CTLs infiltrate the ischemic infarct within 1 h of reperfusion. There was a significant increase in Gra-b levels in the ischemic region starting from 1 h until 3 day which correlated with increased levels of chemokines (IP-10/CXCL10, IL-2) and TNF-alpha. Co-immunoprecipitation experiments show that Gra-b interacts with Bid, PARP, and caspase-3 in ischemic samples. Immunofluorescence analysis of Gra-b and TUNEL showed that Gra-b is present both in apoptotic and necrotic cells. Triple immunostaining further confirmed that the Gra-b positive degenerating cells were neurons. CTLs in close spatial proximity to degenerating neurons, increased levels of Gra-b, localization in neurons positive for TUNEL, and interaction with other pro-apoptotic proteins indicate that Gra-b and CTLs play a significant role in neuronal death following cerebral ischemia in the rat brain after tMCAO. Based on the above findings we support our hypothesis that Gra-b secreted from activated CTLs might be involved in aggravating post-ischemic damage by mediating neuronal death.