Elevated Levels of MMP-9 and TIMP-1 in the Cerebrospinal Fluid of Children with Echovirus Type 30 and Mumps Meningitis

Hsp70 Is a Potential Therapeutic Target for Echovirus 9 Infection

Echovirus is an important cause of viral pneumonia and encephalitis in infants, neonates, and young children worldwide. However, the exact mechanism of its pathogenesis is still not well understood. Here, we established an echovirus type 9 infection mice model, and performed two-dimensional gel electrophoresis (2DE) and tandem mass spectrometry (MS/MS)-based comparative proteomics analysis to investigate the differentially expressed host proteins in mice brain. A total of 21 differentially expressed proteins were identified by MS/MS. The annotation of the differentially expressed proteins by function using the UniProt and GO databases identified one viral protein (5%), seven cytoskeletal proteins (33%), six macromolecular biosynthesis and metabolism proteins (28%), two stress response and chaperone binding proteins (9%), and five other cellular proteins (25%). The subcellular locations of these proteins were mainly found in the cytoskeleton, cytoplasm, nucleus, mitochondria, and Golgi apparatus. The protein expression profiles and the results of quantitative RT-PCR in the detection of gene transcripts were found to complement each other. The differential protein interaction network was predicted using the STRING database. Of the identified proteins, heat shock protein 70 (Hsp70), showing consistent results in the proteomics and transcriptomic analyses, was analyzed through Western blotting to verify the reliability of differential protein expression data in this study. Further, evaluation of the function of Hsp70 using siRNA and quercetin, an inhibitor of Hsp70, showed that Hsp70 was necessary for the infection of echovirus type 9. This study revealed that echovirus infection could cause the differential expression of a series of host proteins, which is helpful to reveal the pathogenesis of viral infection and identify therapeutic drug targets. Additionally, our results suggest that Hsp70 could be a useful therapeutic host protein target for echovirus infection.

Divergent cerebrospinal fluid cytokine network induced by non-viral and different viral infections on the central nervous system

Background

Meningoencephalitis is one of the most common disorders of the central nervous system (CNS) worldwide. Viral meningoencephalitis differs from bacterial meningitis in several aspects. In some developing countries, bacterial meningitis has appropriate clinical management and chemotherapy is available. Virus-associated and virus not detected meningoencephalitis are treatable, however, they may cause death in a few cases. The knowledge of how mediators of inflammation can induce disease would contribute for the design of affordable therapeutic strategies, as well as to the diagnosis of virus not detected and viral meningoencephalitis. Cytokine-induced inflammation to CNS requires several factors that are not fully understood yet.

Methods

Considering this, several cytokines were measured in the cerebrospinal fluid (CSF) of patients with undiagnosed and viral meningoencephalitis, and these were correlated with cellularity in the CSF.

Results

The results demonstrate that an altered biochemical profile alongside increased cellularity in the cerebrospinal fluid is a feature of patients with meningoencephalitis that are not associated with the detection of virus in the CNS (P < 0.05). Moreover, HIV-positive patients (n = 10) that evolve with meningoencephalitis display a distinct biochemical/cytological profile (P < 0.05) in the cerebrospinal fluid. Meningoencephalitis brings about a prominent intrathecal cytokine storm regardless of the detection of virus as presumable etiological agent. In the case of Enterovirus infection (n = 13), meningoencephalitis elicits robust intrathecal pro-inflammatory cytokine pattern and elevated cellularity when compared to herpesvirus (n = 15) and Arbovirus (n = 5) viral infections (P < 0.05).

Conclusion

Differences in the cytokine profile of the CSF may be unique if distinct, viral or presumably non-viral pathways initially trigger the inflammatory response in the CNS.

Type-I interferons induce lung protease responses following respiratory syncytial virus infection via RIG-I-like receptors

The role of proteases in viral infection of the lung is poorly understood. Thus, we examined matrix metalloproteinases (MMPs) and cathepsin proteases in respiratory syncytial virus (RSV)-infected mouse lungs. RSV-induced gene expression for MMPs -2, -3, -7, -8, -9, -10, -12, -13, -14, -16, -17, -19, -20, -25, -27, and -28 and cathepsins B, C, E, G, H, K, L1, S, W, and Z in the airways of Friend leukemia virus B sensitive strain mice. Increased proteases were present in the bronchoalveolar lavage fluid (BALF) and lung tissue during infection. Mitochondrial antiviral-signaling protein (MAVS) and TIR-domain-containing adapter-inducing interferon-β-deficient mice were exposed to RSV. Mavs-deficient mice had significantly lower expression of airway MMP-2, -3, -7, -8, -9, -10, -12, -13, and -28 and cathepsins C, G, K, S, W, and Z. In lung epithelial cells, retinoic acid-inducible gene-1 (RIG-I) was identified as the major RIG-I-like receptor required for RSV-induced protease expression via MAVS. Overexpression of RIG-I or treatment with interferon-β in these cells induced MMP and cathepsin gene and protein expression. The significance of RIG-1 protease induction was demonstrated by the fact that inhibiting proteases with batimastat, E64 or ribavirin prevented airway hyperresponsiveness and enhanced viral clearance in RSV-infected mice.

Increased levels of cytokines in cerebrospinal fluid of children with aseptic meningitis caused by mumps virus and echovirus 30

We measured levels of pro-inflammatory cytokines in the cerebrospinal fluid (CSF) of patients with mumps meningitis, enteroviral echovirus 30 meningitis and children without central nervous system infection to investigate whether these molecules were involved in the pathogenesis of viral meningitis. The CSF was obtained from 62 children suspected with meningitis. These patients were classified to the mumps meningitis (n = 19), echovirus 30 meningitis (n = 22) and non-meningitis (n = 21) groups. The concentrations of interleukin-1 (IL-1), interleukin-1 soluble receptor type 2 (IL-1R2), interleukin-8 (IL-8), human interferon gamma (IFN-γ) and human tumour necrosis factor alpha (TNF-α) were determined by immunoassay. A significant increase was noted in the levels of IL-8, TNF-α and IL-1R2 in the CSF of both meningitis groups as compared to controls. The concentrations of IFN-γ and IL-1 differed significantly only between the mumps group and control. The levels of IL-1, IFN-γ and TNF-α were significantly higher in mumps meningitis when compared to the echovirus 30 group. Of all cytokines examined, only IFN-γ correlated with pleocytosis (r = 0.58) in the mumps meningitis group. The increased CSF cytokine levels are markers of meningeal inflammation, and each virus may cause a specific profile of the cytokine pattern.

Expression of matrix metalloproteinases and their tissue inhibitors in the serum and cerebrospinal fluid of patients with meningitis

Meningitis is associated with an imbalance between matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMP (TIMPs). Serum and CSF were collected prospectively from all patients with meningitis between January 2008 and December 2008 to measure the concentrations of MMP/TIMP in those patients who underwent a lumbar puncture for a presumptive diagnosis of meningitis. A total of 199 patients were enrolled into the study. The concentrations of CSF MMP-9 and TIMP-1 were significantly higher in the meningitis group compared with the control group (p 0.032 and p <0.001, respectively). However, the CSF TIMP-4 levels were significantly lower in the meningitis groups compared with the control groups (p <0.001). Patients with bacterial meningitis had higher CSF MMP-9 and TIMP-1 levels than those who had aseptic meningitis and controls. Patients with various infectious meningitis etiologies tended to have higher CSF MMP-9 expression by gelatin zymography when compared with the controls. In conclusion, MMP/TIMP system dysregulation was found in patients with meningitis, and CSF MMP and TIMP might act as novel indicators in patients with meningitis.

Increased expression of matrix metalloproteinase-9 and hepatocyte growth factor in the cerebrospinal fluid of infants with posthemorrhagic hydrocephalus

BACKGROUND

In approximately 60% of infants with posthemorrhagic hydrocephalus (PHH), ventricular dilation resolves by unknown intrinsic mechanisms, without the need for a shunt operation. A pathological hallmark of PHH is extensive deposition of extracellular matrix (ECM) proteins in the subarachnoid space. Our previous study revealed that matrix metalloproteinase (MMP)-9, which degrades ECM proteins, may play an important role in the resolution of ventricular dilation. MMP-9 is known to be induced by hepatocyte growth factor (HGF) in various cell lines.

AIMS

The aim of this study is to confirm our earlier finding that MMP-9 contributes to the resolution of PHH, and to investigate whether HGF also contributes to this process.

STUDY DESIGN

Cerebrospinal fluid (CSF) samples were collected from 13 infants who developed ventricular dilation after intraventricular hemorrhage (IVH). Of these infants, 9 exhibited resolution of ventricular dilation without shunt operation; however, 4 infants had to be treated with shunt operation. The CSF levels of MMP-9 and HGF were measured using an enzyme immunoassay.

RESULTS

Significantly higher CSF levels of MMP-9 and HGF were detected in patients in whom the ventricular dilation resolved without shunt operation than in those with progressive ventricular dilation (MMP-9: median, 128ng/ml; range, 47-900ng/ml vs median, 50ng/ml; range, 12-110ng/ml; p<0.05; HGF: median, 2.42ng/ml; range, 0.81-7.04ng/ml vs median, 1.42ng/ml; range, 0.67-3.87ng/ml; p<0.05).

CONCLUSIONS

Our results indicate that MMP-9 and HGF may participate in the resolution of ventricular dilation following IVH.

Dexamethasone, cerebrospinal fluid matrix metalloproteinase concentrations and clinical outcomes in tuberculous meningitis

Background

Adjunctive dexamethasone reduces mortality from tuberculous meningitis, but how it produces this effect is not known. Matrix metalloproteinases (MMPs) are important in the immunopathology of many inflammatory CNS diseases thus we hypothesized that that their secretion is important in TBM and might be influenced by dexamethasone.

Methodology/Principal Findings

The kinetics of cerebrospinal fluid (CSF) MMP and tissue inhibitors of MMPs (TIMPs) concentrations were studied in a subset of HIV uninfected adults (n = 37) with TBM recruited to a randomized, placebo-controlled trial of adjuvant dexamethasone. Analysis followed a pre-defined plan. Dexamethasone significantly reduced CSF MMP-9 concentrations in early follow up samples (median 5 days (range 3–8) of treatment), but had no significant influence on other MMPs/TIMPs. Additionally CSF MMP-9 concentration was strongly correlated to concomitant CSF neutrophil count.

Conclusions/Significance

Dexamethasone decreased CSF MMP-9 concentrations early in treatment and this may represent one mechanism by which corticosteroids improve outcome in TBM. The strong correlation between CSF MMP-9 and neutrophil count suggests that polymorphonuclear leukocytes may play a central role in the early pathogenesis of TBM.