Neuronal and glial cerebrospinal fluid protein biomarkers are elevated after West Nile virus infection

Modelling amoebic brain infection caused by Balamuthia mandrillaris using a human cerebral organoid

The lack of disease models adequately resembling human tissue has hindered our understanding of amoebic brain infection. Three-dimensional structured organoids provide a microenvironment similar to human tissue. This study demonstrates the use of cerebral organoids to model a rare brain infection caused by the highly lethal amoeba Balamuthia mandrillaris. Cerebral organoids were generated from human pluripotent stem cells and infected with clinically isolated B. mandrillaris trophozoites. Histological examination showed amoebic invasion and neuron damage following coculture with the trophozoites. The transcript profile suggested an alteration in neuron growth and a proinflammatory response. The release of intracellular proteins specific to neuronal bodies and astrocytes was detected at higher levels postinfection. The amoebicidal effect of the repurposed drug nitroxoline was examined using the human cerebral organoids. Overall, the use of human cerebral organoids was important for understanding the mechanism of amoeba pathogenicity, identify biomarkers for brain injury, and in the testing of a potential amoebicidal drug in a context similar to the human brain.

Serum and cerebrospinal fluid brain damage markers neurofilament light and glial fibrillary acidic protein correlate with tick-borne encephalitis disease severity-a multicentre study on Lithuanian and Swedish patients

BACKGROUND AND PURPOSE

Our aim was to examine the correlation between biomarkers of neuronal and glial cell damage and severity of disease in patients with tick-borne encephalitis.

METHODS

One hundred and fifteen patients with tick-borne encephalitis diagnosed in Lithuania and Sweden were prospectively included, and cerebrospinal fluid (CSF) and serum samples were obtained shortly after hospitalization. Using pre-defined criteria, cases were classified as mild, moderate or severe tick-borne encephalitis. Additionally, the presence of spinal nerve paralysis (myelitis) and/or cranial nerve affection were noted. Concentrations of the brain cell biomarkers glial fibrillary acidic protein (GFAP), YKL-40, S100B, neurogranin, neurofilament light (NfL) and tau were analysed in CSF and, in addition, NfL, GFAP and S100B levels were measured in serum. The Jonckheere-Terpstra test was used for group comparisons of continuous variables and Spearman's partial correlation test was used to adjust for age.

RESULTS

Cerebrospinal fluid and serum concentrations of GFAP and NfL correlated with disease severity, independent of age, and with the presence of nerve paralysis. The markers neurogranin, YKL-40, tau and S100B in CSF and S100B in serum were detected, but their concentrations did not correlate with disease severity.

CONCLUSIONS

Neuronal cell damage and astroglial cell activation with increased NfL and GFAP in CSF and serum were associated with a more severe disease, independent of age. Increased GFAP and NfL concentrations in CSF and NfL in serum were also indicative of spinal and/or cranial nerve damage. NfL and GFAP are promising prognostic biomarkers in tick-borne encephalitis, and future studies should focus on determining the association between these biomarkers and long-term sequelae.

Protocol to Study West Nile Virus Infection in Brain Slices In Vitro

Ex vivo slice cultures of the brain tissue can maintain the cytoarchitecture of the central nervous system (CNS), which allows a thorough understanding of the functions of multiple interconnected cells in a culture system that closely resembles the in vivo environment. Additionally, slice cultures of the brain tissue are advantageous in tracking complex connectivity between neurons and glia both under normal and pathologic conditions, which is not possible in in vitro cell lines. Here, we describe the method of preparing ex vivo slice culture from the mouse cerebellum and the protocol of studying the effects of West Nile virus infection on cerebellar cells.

The 2022 Lady Estelle Wolfson lectureship on neurofilaments

Neurofilament proteins (Nf) have been validated and established as a reliable body fluid biomarker for neurodegenerative pathology. This review covers seven Nf isoforms, Nf light (NfL), two splicing variants of Nf medium (NfM), two splicing variants of Nf heavy (NfH), α -internexin (INA) and peripherin (PRPH). The genetic and epigenetic aspects of Nf are discussed as relevant for neurodegenerative diseases and oncology. The comprehensive list of mutations for all Nf isoforms covers Amyotrophic Lateral Sclerosis, Charcot-Marie Tooth disease, Spinal muscular atrophy, Parkinson Disease and Lewy Body Dementia. Next, emphasis is given to the expanding field of post-translational modifications (PTM) of the Nf amino acid residues. Protein structural aspects are reviewed alongside PTMs causing neurodegenerative pathology and human autoimmunity. Molecular visualisations of NF PTMs, assembly and stoichiometry make use of Alphafold2 modelling. The implications for Nf function on the cellular level and axonal transport are discussed. Neurofilament aggregate formation and proteolytic breakdown are reviewed as relevant for biomarker tests and disease. Likewise, Nf stoichiometry is reviewed with regard to in vitro experiments and as a compensatory mechanism in neurodegeneration. The review of Nf across a spectrum of 87 diseases from all parts of medicine is followed by a critical appraisal of 33 meta-analyses on Nf body fluid levels. The review concludes with considerations for clinical trial design and an outlook for future research.

Blood GFAP as an emerging biomarker in brain and spinal cord disorders

Blood-derived biomarkers for brain and spinal cord diseases are urgently needed. The introduction of highly sensitive immunoassays led to a rapid increase in the number of potential blood-derived biomarkers for diagnosis and monitoring of neurological disorders. In 2018, the FDA authorized a blood test for clinical use in the evaluation of mild traumatic brain injury (TBI). The test measures levels of the astrocytic intermediate filament glial fibrillary acidic protein (GFAP) and neuroaxonal marker ubiquitin carboxy-terminal hydrolase L1. In TBI, blood GFAP levels are correlated with clinical severity and extent of intracranial pathology. Evidence also indicates that blood GFAP levels hold the potential to reflect, and might enable prediction of, worsening of disability in individuals with progressive multiple sclerosis. A growing body of evidence suggests that blood GFAP levels can be used to detect even subtle injury to the CNS. Most importantly, the successful completion of the ongoing validation of point-of-care platforms for blood GFAP might ameliorate the decision algorithms for acute neurological diseases, such as TBI and stroke, with important economic implications. In this Review, we provide a systematic overview of the evidence regarding the utility of blood GFAP as a biomarker in neurological diseases. We propose a model for GFAP concentration dynamics in different conditions and discuss the limitations that hamper the widespread use of GFAP in the clinical setting. In our opinion, the clinical use of blood GFAP measurements has the potential to contribute to accelerated diagnosis and improved prognostication, and represents an important step forward in the era of precision medicine.

Insights into the biomarkers of viral encephalitis from clinical patients

BACKGROUND

biomarkers can be helpful in identifying patients who may profit by explicit treatments or evaluating the reaction to the treatment of specific disease. Finding unique biomarkers in the process of disease could help clinicians in identifying serious disease in the early stage, so as to improve prognosis.

OBJECTIVE

these investigations, nonetheless, have made constrained progress. Numerous infections are known to cause intense viral encephalitis (VE) in people which can cause a variable level of meningeal just as parenchymal aggravation. Initial clinical manifestations in most encephalitis are nonspecific, resembling a viral-like illness. However, with disease progression, symptoms can become quite severe and fatal, including prominent cranial hypertension, cognitive problems, cerebral hernia and respiratory failure. Forwards: the clinical and research center discoveries in huge numbers of those viral issues are to a great extent comparable and in this way increasingly explicit biomarkers for indicative and prognostic intentions are justified. These biomarkers are progressively significant in the acknowledgment and treatment of the viral central nervous system (CNS) issue.

CONCLUSION

Clinical manifestations have been the indicative approaches for analysis of viral encephalitis. Lots of studies have been endeavored to distinguish progressively objective laboratory-based quantitative CSF biomarkers for VE.

Current Understanding of West Nile Virus Clinical Manifestations, Immune Responses, Neuroinvasion, and Immunotherapeutic Implications

West Nile virus (WNV) is the most common mosquito-borne virus in North America. WNV-associated neuroinvasive disease affects all ages, although elderly and immunocompromised individuals are particularly at risk. WNV neuroinvasive disease has killed over 2300 Americans since WNV entered into the United States in the New York City outbreak of 1999. Despite 20 years of intensive laboratory and clinical research, there are still no approved vaccines or antivirals available for human use. However, rapid progress has been made in both understanding the pathogenesis of WNV and treatment in clinical practices. This review summarizes our current understanding of WNV infection in terms of human clinical manifestations, host immune responses, neuroinvasion, and therapeutic interventions.

Differential Expression of Genes Related to Innate Immune Responses in Ex Vivo Spinal Cord and Cerebellar Slice Cultures Infected with West Nile Virus

West Nile virus (WNV) infection results in a spectrum of neurological symptoms, ranging from a benign fever to severe WNV neuroinvasive disease with high mortality. Many who recover from WNV neuroinvasive infection present with long-term deficits, including weakness, fatigue, and cognitive problems. While neurons are a main target of WNV, other cell types, especially astrocytes, play an important role in promoting WNV-mediated central nervous system (CNS) damage. Conversely, it has been shown that cultured primary astrocytes secrete high levels of interferons (IFNs) immediately after WNV exposure to protect neighboring astrocytes, as well as neurons. However, how intrinsic responses to WNV in specific cell types and different regions of the brain modify immune protection is not fully understood. Here, we used a mouse ex vivo spinal cord slice culture (SCSC) and cerebellar slice culture (CSC) models to determine the innate immune responses specific to the CNS during WNV infection. Slices were prepared from the spinal cord and cerebellar tissue of 7–9-day-old mouse pups. Four-day-old SCSC or CSC were infected with 1 × 10³ or 1 × 10⁵ PFU of WNV, respectively. After 12 h exposure to WNV and 3 days post-infection in normal growth media, the pooled slice cultures were processed for total RNA extraction and for gene expression patterns using mouse Affymetrix arrays. The expression patterns of a number of genes were significantly altered between the mock- and WNV-treated groups, both in the CSCs and SCSCs. However, distinct differences were observed when CSC data were compared with SCSC. CSCs showed robust induction of interferons (IFNs), IFN-stimulated genes (ISGs), and regulatory factors. Some of the antiviral genes related to IFN were upregulated more than 25-fold in CSCs as compared to mock or SCSC. Though SCSCs had twice the number of dysregulated genes, as compared CSCs, they exhibited a much subdued IFN response. In addition, SCSCs showed astrogliosis and upregulation of astrocytic marker genes. In sum, our results suggest that early anti-inflammatory response to WNV infection in CSCs may be due to large population of distinct astrocytic cell types, and lack of those specialized astrocytes in SCSC may make spinal cord cells more susceptible to WNV damage. Further, the understanding of early intrinsic immune response events in WNV-infected ex vivo culture models could help develop potential therapies against WNV.

West Nile virus induces a post-infectious pro-inflammatory state that explains transformation of stable ocular myasthenia gravis to myasthenic crises

West Nile virus (WNV) infection has been reported to promote myasthenia gravis (MG) and various other diseases that have a presumed autoimmune pathogenesis. Molecular mimicry between WNV proteins and host proteins has been postulated as the major mechanism for WNV-triggered breaking of immunological self-tolerance. We present a patient with stable ocular MG and positive anti-acetylcholine receptor antibodies who progressed to myasthenic crisis after WNV neuroinvasive disease. In this case of stable autoimmune disease with proven auto-antibodies, transformation to generalized disease cannot be attributed to molecular mimicry, which requires that an immune response first be generated against an infectious agent. Rather, the evidence supports the concept of a post-infectious pro-inflammatory state that may contribute to the amplification and promotion of autoimmune disease in some WNV survivors.

Translational evidence for two distinct patterns of neuroaxonal injury in sepsis: a longitudinal, prospective translational study

Background

Brain homeostasis deteriorates in sepsis, giving rise to a mostly reversible sepsis-associated encephalopathy (SAE). Some survivors experience chronic cognitive dysfunction thought to be caused by permanent brain injury. In this study, we investigated neuroaxonal pathology in sepsis.

Methods

We conducted a longitudinal, prospective translational study involving (1) experimental sepsis in an animal model; (2) postmortem studies of brain from patients with sepsis; and (3) a prospective, longitudinal human sepsis cohort study at university laboratory and intensive care units (ICUs). Thirteen ICU patients with septic shock, five ICU patients who died as a result of sepsis, fourteen fluid-resuscitated Wistar rats with fecal peritonitis, eleven sham-operated rats, and three human and four rat control subjects were included. Immunohistologic and protein biomarker analysis were performed on rat brain tissue at baseline and 24, 48, and 72 h after sepsis induction and in sham-treated rats. Immunohistochemistry was performed on human brain tissue from sepsis nonsurvivors and in control patients without sepsis. The clinical diagnostics of SAE comprised longitudinal clinical data collection and magnetic resonance imaging (MRI) and electroencephalographic assessments. Statistical analyses were performed using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA). Because of non-Gaussian distribution, the nonparametric Wilcoxon test general linear models and the Spearman correlation coefficient were used.

Results

In postmortem rat and human brain samples, neurofilament phosphoform, β-amyloid precursor protein, β-tubulin, and H&E stains distinguished scattered ischemic lesions from diffuse neuroaxonal injury in septic animals, which were absent in controls. These two patterns of neuroaxonal damage were consistently found in septic but not control human postmortem brains. In experimental sepsis, the time from sepsis onset correlated with tissue neurofilament levels (R = 0.53, p = 0.045) but not glial fibrillary acidic protein. Of 13 patients with sepsis who had clinical features of SAE, MRI detected diffuse axonal injury in 9 and ischemia in 3 patients.

Conclusions

Ischemic and diffuse neuroaxonal injury to the brain in experimental sepsis, human postmortem brains, and in vivo MRI suggest these two distinct lesion types to be relevant. Future studies should be focused on body fluid biomarkers to detect and monitor brain injury in sepsis. The relationship of neurofilament levels with time from sepsis onset may be of prognostic value.

Trial registration

ClinicalTrials.gov, NCT02442986. Registered on May 13, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1850-7) contains supplementary material, which is available to authorized users.

Nilotinib Effects in Parkinson's disease and Dementia with Lewy bodies

BACKGROUND

We evaluated the effects of low doses of the tyrosine kinase Abelson (Abl) inhibitor Nilotinib, on safety and pharmacokinetics in Parkinson's disease dementia or dementia with Lewy bodies.

OBJECTIVES

The primary outcomes of this study were safety and tolerability; pharmacokinetics and target engagement were secondary, while clinical outcomes were exploratory.

METHODS

Twelve subjects were randomized into 150 mg (n = 5) or 300 mg (n = 7) groups and received Nilotinib orally every day for 24 weeks.

RESULTS

This study shows that 150 mg and 300 mg doses of Nilotinib appear to be safe and tolerated in subjects with advanced Parkinson's disease. Nilotinib is detectable in the cerebrospinal fluid (CSF) and seems to engage the target Abl. Motor and cognitive outcomes suggest a possible beneficial effect on clinical outcomes. The CSF levels of homovanillic acid are significantly increased between baseline and 24 weeks of treatment. Exploratory CSF biomarkers were measured.

CONCLUSIONS

This small proof-of-concept study lacks a placebo group and participants were not homogenous, resulting in baseline differences between and within groups. This limits the interpretations of the biomarker and clinical data, and any conclusions should be drawn cautiously. Nonetheless, the collective observations suggest that it is warranted to evaluate the safety and efficacy of Nilotinib in larger randomized, double-blind, placebo-controlled trials.

Elevated levels of cerebrospinal fluid S100B are associated with brain injury and unfavorable outcomes in children with central nervous system infections

PURPOSE

This work aimed to assess whether elevated levels of cerebrospinal fluid (CSF) S100B are associated with brain injury and unfavorable outcomes at discharge in children with central nervous system (CNS) infections.

METHODS

CSF S100B and associated clinical parameters were retrospectively analyzed in 83 children with CNS infections and 88 children without neurological pathology served as controls. Children with CNS infections were divided into an infectious encephalitis group and an infectious meningitis group based on whether cerebral parenchyma was involved, and CSF S100B levels in different age subgroups between the two groups were compared. The predictive value of CSF S100B in children with infectious encephalitis was evaluated by multivariate logistic regression analysis, and the discriminative power was investigated by receiver operating characteristic (ROC) analysis.

RESULTS

CSF S100B levels in the infectious encephalitis group were significantly higher than the infectious meningitis and the control group at each age range. CSF S100B ≥ 0.96 μg/L had 62.9% sensitivity and 76.2% specificity for diagnosing cerebral parenchyma injury in children with CNS infections. Increased CSF S100B levels were proven to be an independent predictor of unfavorable outcomes in children with infectious encephalitis and the optimal cut-off value (1.77 μg/L of CSF S100B) for predicting unfavorable outcomes in children with infectious encephalitis showed 61.1% sensitivity and 96.2% specificity.

CONCLUSIONS

This study has demonstrated that elevated levels of CSF S100B are associated with brain injury and could be used as an independent predictor of clinically unfavorable outcomes at discharge in children with CNS infections.

Elevated vitreous body glial fibrillary acidic protein in retinal diseases

Purpose

Increased expression of glial fibrillary acidic protein (GFAP) is a characteristic of gliotic activation (Müller cells and astrocytes) in the retina. This study assessed vitreous body GFAP levels in various forms of retinal pathology.

Methods

This prospective study included 82 patients who underwent vitrectomy (46 retinal detachments (RDs), 13 macular hole (MHs), 15 epiretinal glioses (EGs), 8 organ donors). An established enzyme–linked immunosorbent assay (ELISA, SMI26) was used for quantification of GFAP.

Results

The highest concentration of vitreous body GFAP in organ donors was 20 pg/mL and it was used as the cutoff. A significant proportion of patients suffering from RD (65 %) to EG (53 %) had vitreous body GFAP levels above this cutoff when compared to organ donors (0 %, p < 0.0001, p = 0.0194, respectively, Fisher’s exact test) and MH (8 %, p < 0.0001, p = 0.0157, respectively). In RD and EG, vitreous body GFAP levels were correlated with axial length (R = 0.69, R = 0.52, p < 0.05 for both).

Conclusions

The data suggest that human vitreous body GFAP is a protein biomarker for glial activation in response to retinal pathologies. Vitreous body GFAP levels may be of interest as a surrogate outcome for experimental treatment strategies in translational studies.

Reduced immune cell infiltration and increased pro-inflammatory mediators in the brain of Type 2 diabetic mouse model infected with West Nile virus

Background

Diabetes is a significant risk factor for developing West Nile virus (WNV)-associated encephalitis (WNVE) in humans, the leading cause of arboviral encephalitis in the United States. Using a diabetic mouse model (db/db), we recently demonstrated that diabetes enhanced WNV replication and the susceptibility of mice to WNVE. Herein, we have examined immunological events in the brain of wild type (WT) and db/db mice after WNV infection. We hypothesized that WNV-induced migration of protective leukocytes into the brain is attenuated in the presence of diabetes, leading to a high viral load in the brain and severe disease in diabetic mice.

Methods

Nine-week old C57BL/6 WT and db/db mice were infected with WNV. Leukocyte infiltration, expression of cell adhesion molecules (CAM), neuroinflammatory responses, activation of astrocytes, and neuronal death were analyzed using immunohistochemistry, qRT-PCR, flow cytometry, and western blot.

Results

We demonstrate that infiltration of CD45⁺ leukocytes and CD8⁺T cells was significantly reduced in the brains of db/db mice, which was correlated with attenuated expression of CAM such as E-selectin and ICAM-1. WNV infection in db/db mice was associated with an enhanced inflammatory response in the brain. mRNA and protein levels of key chemokines such as CXCL10, CXCL1, CCL2, CCL5, CCL3, and G-CSF, and cytokines such as IL-1β, TNF, IL-6, IFNγ, and IL-1α were significantly elevated in the brains of db/db mice compared to WT mice. Elevated levels of cytokines also correlated with increased astrocytes activation and neuronal damage in the brains of db/db mice.

Conclusion

These data suggest that reduced leukocytes recruitment, in part, due to lower levels of CAM results in failure to clear WNV infection from the brain leading to increased production of inflammatory molecules, which mediates increased neuronal death and mortality in db/db mice. This is the first study to elucidate the expression of CAM and their correlation with the migration of leukocytes, specifically cytotoxic CD8⁺ T cells, in increasing disease severity in the diabetic mouse model.

Cerebrospinal fluid biomarker candidates associated with human WNV neuroinvasive disease

During the last decade, the epidemiology of WNV in humans has changed in the southern regions of Europe, with high incidence of West Nile fever (WNF) cases, but also of West Nile neuroinvasive disease (WNND). The lack of human vaccine or specific treatment against WNV infection imparts a pressing need to characterize indicators associated with neurological involvement. By its intimacy with central nervous system (CNS) structures, modifications in the cerebrospinal fluid (CSF) composition could accurately reflect CNS pathological process. Until now, few studies investigated the association between imbalance of CSF elements and severity of WNV infection. The aim of the present study was to apply the iTRAQ technology in order to identify the CSF proteins whose abundances are modified in patients with WNND. Forty-seven proteins were found modified in the CSF of WNND patients as compared to control groups, and most of them are reported for the first time in the context of WNND. On the basis of their known biological functions, several of these proteins were associated with inflammatory response. Among them, Defensin-1 alpha (DEFA1), a protein reported with anti-viral effects, presented the highest increasing fold-change (FC>12). The augmentation of DEFA1 abundance in patients with WNND was confirmed at the CSF, but also in serum, compared to the control individual groups. Furthermore, the DEFA1 serum level was significantly elevated in WNND patients compared to subjects diagnosed for WNF. The present study provided the first insight into the potential CSF biomarkers associated with WNV neuroinvasion. Further investigation in larger cohorts with kinetic sampling could determine the usefulness of measuring DEFA1 as diagnostic or prognostic biomarker of detrimental WNND evolution.

Neurofilament heavy chain as a marker of neuroaxonal pathology and prognosis in acute encephalitis

BACKGROUND AND PURPOSE

The neurological outcome of acute encephalitis can be devastating and early prognosis remains difficult. Biomarkers that quantify the extent of early brain injury are needed to improve the prognostic accuracy and aid patient management. Our objective was to assess whether cerebrospinal fluid (CSF) protein biomarkers of neuroaxonal and glial cell injury are elevated in distinct forms of acute encephalitis and predictive of poor outcome.

METHODS

This was a prospective study of patients presenting with acute encephalitis to three teaching hospitals in London, UK. Levels of neurofilament heavy chain (NfH, SMI35) and S100B were quantified in CSF using enzyme-linked immunosorbent assay. The outcome was assessed by the Glasgow Outcome Scale (GOS).

RESULTS

Fifty-six patients with acute encephalitis were recruited and classified into the following diagnostic categories: infectious (n = 20), inflammatory (n = 14) and unknown etiology (n = 22). Pathological levels of NfH and S100B were observed in 24/56 (43%) and 54/56 (96%), respectively. Patients with infectious encephalitis had significantly higher NfH levels compared with the other two groups (P < 0.05). A poor outcome (GOS < 5) was associated with significantly higher CSF NfH levels within samples taken 2 weeks after symptom onset.

CONCLUSIONS

This study suggests that longitudinal CSF NfH levels are of superior prognostic value compared with CSF S100B levels. Prolonged release of NfH, a marker of neuroaxonal damage, was associated with poor outcome. Potentially there is a window of opportunity for future neuroprotective treatment strategies in encephalitis.

CSF neurofilament light chain is elevated in OMS (decreasing with immunotherapy) and other pediatric neuroinflammatory disorders

Using a panel of seven brain cell-specific biomarkers in cerebrospinal fluid (CSF), pediatric opsoclonus-myoclonus syndrome (OMS) (n=234) was compared to pediatric non-inflammatory neurological controls (n=84) and other inflammatory neurological disorders (OIND) (n=44). Only CSF NFL was elevated in untreated OMS versus controls (+83%). It was 87% higher in OIND than in OMS. On combination treatment with front-loaded ACTH, IVIg, rituximab, median CSF NFL decreased by 60% to control levels. These biochemical data suggest neuronal/axonal injury in some children with OMS without indicators of astrogliosis, and reduction on sufficient immunotherapy.

Altered protein networks and cellular pathways in severe west nile disease in mice

Background

The recent West Nile virus (WNV) outbreaks in developed countries, including Europe and the United States, have been associated with significantly higher neuropathology incidence and mortality rate than previously documented. The changing epidemiology, the constant risk of (re-)emergence of more virulent WNV strains, and the lack of effective human antiviral therapy or vaccines makes understanding the pathogenesis of severe disease a priority. Thus, to gain insight into the pathophysiological processes in severe WNV infection, a kinetic analysis of protein expression profiles in the brain of WNV-infected mice was conducted using samples prior to and after the onset of clinical symptoms.

Methodology/Principal Findings

To this end, 2D-DIGE and gel-free iTRAQ labeling approaches were combined, followed by protein identification by mass spectrometry. Using these quantitative proteomic approaches, a set of 148 proteins with modified abundance was identified. The bioinformatics analysis (Ingenuity Pathway Analysis) of each protein dataset originating from the different time-point comparisons revealed that four major functions were altered during the course of WNV-infection in mouse brain tissue: i) modification of cytoskeleton maintenance associated with virus circulation; ii) deregulation of the protein ubiquitination pathway; iii) modulation of the inflammatory response; and iv) alteration of neurological development and neuronal cell death. The differential regulation of selected host protein candidates as being representative of these biological processes were validated by western blotting using an original fluorescence-based method.

Conclusion/Significance

This study provides novel insights into the in vivo kinetic host reactions against WNV infection and the pathophysiologic processes involved, according to clinical symptoms. This work offers useful clues for anti-viral research and further evaluation of early biomarkers for the diagnosis and prevention of severe neurological disease caused by WNV.

Cerebrospinal fluid biomarkers in patients with varicella-zoster virus CNS infections

Varicella-zoster virus (VZV) is one of our most common viruses causing central nervous system (CNS) infection with sometimes severe neurological complications. Glial fibrillary acidic protein (GFAp), light subunit of neurofilament protein (NFL) and S-100β protein are cerebrospinal fluid (CSF) biomarkers that have been used to estimate the severity of brain damage and outcome in various CNS diseases. So far, these biomarkers have not been utilised to investigate glial pathology and neuronal damage in patients with VZV CNS infections. In this prospective study, we measured CSF GFAp, NFL and S-100β as markers of brain damage in 24 patients with acute neurological manifestations and VZV DNA detected in CSF by PCR and compared with a control group (n = 14). Concentrations of CSF NFL and GFAp were increased in patients with VZV CNS infection compared with controls (p = 0.002 and p = 0.03) while levels of S-100β were reduced. In patients with VZV encephalitis the elevations of CSF NFL and GFAp were more pronounced compared with patients with other VZV CNS syndromes. No correlations between the levels of biomarkers and viral load, neurological sequels or clinical outcome were found in this limited number of patients. These results indicate that VZV induces neuronal damage and astrogliosis with more severe brain damage in patients with VZV encephalitis than in patients with other neurological complications caused by this virus.

Inflammasome adaptor protein Apoptosis-associated speck-like protein containing CARD (ASC) is critical for the immune response and survival in west Nile virus encephalitis

West Nile virus (WNV) is a neurotropic flavivirus that has emerged globally as a significant cause of viral encephalitis in humans. The WNV-induced innate immune response, including production of antiviral cytokines, is critical for controlling virus infection. The adaptor protein ASC mediates a critical step in innate immune signaling by bridging the interaction between the pathogen recognition receptors and caspase 1 in inflammasome complexes, but its role in WNV immunopathogenesis is not defined. Here, we demonstrate that ASC is essential for interleukin-1β (IL-1β) production and development of effective host immunity against WNV. ASC-deficient mice exhibited increased susceptibility to WNV infection, and reduced survival was associated with enhanced virus replication in the peripheral tissues and central nervous system (CNS). Infection of cultured bone marrow-derived dendritic cells showed that ASC was essential for the activation of caspase 1, a key component of inflammasome assembly. ASC(-/-) mice exhibited attenuated levels of proinflammatory cytokines in the serum. Intriguingly, infected ASC(-/-) mice also displayed reduced levels of alpha interferon (IFN-α) and IgM in the serum, indicating the overall protective role of ASC in restricting WNV infection. However, brains from ASC(-/-) mice displayed unrestrained inflammation, including elevated levels of proinflammatory cytokines and chemokines, such as IFN-γ, CCL2, and CCL5, which correlated with more pronounced activation of the astrocytes, enhanced infiltration of peripheral immune cells in the CNS, and increased neuronal cell death. Collectively, our data provide new insights into the role of ASC as an essential modulator of inflammasome-dependent and -independent immune responses to effectively control WNV infection.

Evidence for acute neurotoxicity after chemotherapy

OBJECTIVE

Chronic neurotoxicity is a recognized long-term complication following chemotherapy in a range of diseases. Neurotoxicity adversely affects patients' quality of life. The objective of this study is to examine whether there is evidence of acute neurotoxicity.

METHODS

This prospective study included patients with secondary progressive multiple sclerosis (SPMS-BMT, n = 14) and hematological malignancies (HM-BMT, n = 17) receiving chemotherapy as preconditioning for bone marrow transplant. The control groups included SPMS patients matched for demographic and clinical data (SPMS-PL, n = 14) and healthy controls (n = 14). Neurodegeneration was assessed at baseline and longitudinally (months 1, 2, 3, 6, 9, 12, 24, and 36), combining a clinical scale for disability (Expanded Disability Status Scale [EDSS]), a serum protein biomarker for neurodegeneration (neurofilaments, NfH-SMI35), and brain atrophy measures (magnetic resonance imaging).

RESULTS

Disability progression was significantly more acute and severe following chemotherapy compared to placebo. Immediately after starting chemotherapy, serum NfH-SMI35 levels increased in 79% (p < 0.0001) of SPMS-BMT patients and 41% (p < 0.01) of HM-BMT patients compared to 0% of SPMS-PL patients or healthy controls. In SPMS-BMT serum NfH-SMI35 levels were > 100-fold higher 1 month after chemotherapy (29.73ng/ml) compared to baseline (0.28ng/ml, p < 0.0001). High serum NfH-SMI35 levels persisting for at least 3 months were associated with sustained disability progression on the EDSS (p < 0.05). Brain atrophy rates increased acutely in SPMS-BMT (-2.09) compared to SPMS-PL (-1.18, p < 0.05).

INTERPRETATION

Neurotoxicity is an unwanted acute side effect of aggressive chemotherapy.

Glial fibrillary acidic protein: a potential biomarker for progression in multiple sclerosis

The major intermediate cytoskeletal protein of astrocytes, glial fibrillary acidic protein (GFAP), and that of axons, neurofilament light protein (NFL), may both be released into the cerebrospinal fluid (CSF) during pathological processes in the central nervous system (CNS). We investigated GFAP and NFL levels in CSF as possible biomarkers for progression in multiple sclerosis (MS). Patients with relapsing-remitting MS (RRMS, n = 15) or secondary progressive MS (SPMS, n = 10) and healthy control subjects (n = 28) were examined twice with an interval of 8-10 years apart. Neurological deficits were scored with the Expanded Disability Status Scale (EDSS). GFAP and NFL levels were determined in CSF by enzyme-linked immunosorbent assay (ELISA). GFAP levels and NFL levels correlated with age (r and r (s) = 0.50, p = 0.006). Adjusting for age, MS patients had increased GFAP levels compared with controls (p = 0.03) and GFAP levels correlated with neurological disability (EDSS, r = 0.51, p < 0.05) and disease progression [Multiple Sclerosis Severity Score (MSSS), r = 0.47, p < 0.05]. The mean annual increase of GFAP was 6.5 ng/L for controls, 8.1 ng/L for RRMS patients, and 18.9 ng/L for SPMS patients. GFAP level at the first examination had predictive value for neurological disability 8-10 years later (EDSS, r = 0.45, p < 0.05) but not for EDSS increase between the examinations. NFL levels were not significantly increased in MS patients compared with controls and had no relationship to disability or progression and no prognostic value for disability development. GFAP, a marker for astrogliosis, is a potential biomarker for MS progression and may have a role in clinical trials for assessing the impact of therapies on MS progression.

Pro-inflammatory cytokines derived from West Nile virus (WNV)-infected SK-N-SH cells mediate neuroinflammatory markers and neuronal death

Background

WNV-associated encephalitis (WNVE) is characterized by increased production of pro-inflammatory mediators, glial cells activation and eventual loss of neurons. WNV infection of neurons is rapidly progressive and destructive whereas infection of non-neuronal brain cells is limited. However, the role of neurons and pathological consequences of pro-inflammatory cytokines released as a result of WNV infection is unclear. Therefore, the objective of this study was to examine the role of key cytokines secreted by WNV-infected neurons in mediating neuroinflammatory markers and neuronal death.

Methods

A transformed human neuroblastoma cell line, SK-N-SH, was infected with WNV at multiplicity of infection (MOI)-1 and -5, and WNV replication kinetics and expression profile of key pro-inflammatory cytokines were analyzed by plaque assay, qRT-PCR, and ELISA. Cell death was measured in SK-N-SH cell line in the presence and absence of neutralizing antibodies against key pro-inflammatory cytokines using cell viability assay, TUNEL and flow cytometry. Further, naïve primary astrocytes were treated with UV-inactivated supernatant from mock- and WNV-infected SK-N-SH cell line and the activation of astrocytes was measured using flow cytometry and ELISA.

Results

WNV-infected SK-N-SH cells induced the expression of IL-1β, -6, -8, and TNF-α in a dose- and time-dependent manner, which coincided with increase in virus-induced cell death. Treatment of cells with anti-IL-1β or -TNF-α resulted in significant reduction of the neurotoxic effects of WNV. Furthermore treatment of naïve astrocytes with UV-inactivated supernatant from WNV-infected SK-N-SH cell line increased expression of glial fibrillary acidic protein and key inflammatory cytokines.

Conclusion

Our results for the first time suggest that neurons are one of the potential sources of pro-inflammatory cytokines in WNV-infected brain and these neuron-derived cytokines contribute to WNV-induced neurotoxicity. Moreover, cytokines released from neurons also mediate the activation of astrocytes. Our data define specific role(s) of WNV-induced pro-inflammatory cytokines and provide a framework for the development of anti-inflammatory drugs as much-needed therapeutic interventions to limit symptoms associated with WNVE.