Monocyte secretory profiling in a clinical and MEFV genotype-characterized cohort of Danish familial Mediterranean fever patients: diagnostic potential of CCL1 and CXCL1.

OBJECTIVE: The autoinflammatory disease familial Mediterranean fever (FMF), characterized by recurrent attacks of sterile fever, serosal, and/or synovial inflammation, is caused by variants in the Mediterranean fever gene, MEFV, coding for the pyrin inflammasome sensor. The diagnosis of FMF is mainly based on clinical symptoms and confirmed by detection of disease-associated MEFV variants. However, the diagnosis is challenging among patients carrying variants of uncertain clinical significance (VUS). In this study, we aimed to identify potential FMF discriminatory diagnostic markers in a cohort of clinically characterized FMF patients. METHOD: We established a cohort of clinically and MEFV genotype-characterized FMF patients by enrolling patients from major Danish hospitals (n = 91). The secretory profile of pyrin inflammasome-activated monocytes from healthy donors (HDs) and MEFV-characterized FMF patients (n = 28) was assessed by analysing cell supernatants for a custom-designed panel of 23 cytokines, chemokines, and soluble tumour necrosis factor receptors associated with monocyte and macrophage function. RESULTS: MEFV genotypes in Danish FMF patients were associated with age at symptom onset (p < 0.05), FMF among relatives (p < 0.01), proportion of patients in colchicine treatment (p < 0.01), and treatment response (p < 0.05). Secretion of chemokines CCL1 and CXCL1 from pyrin-activated FMF monocytes was significantly decreased compared to HDs (p < 0.05), and could discriminate FMF patients with 'non-confirmatory' MEFV genotypes from HDs with 80.0% and 70.0% sensitivity for CCL1 and CXCL1, respectively (p < 0.05). CONCLUSION: Our data suggest that a functional diagnostic assay based on CCL1 or CXCL1 levels in pyrin-activated patient monocytes may contribute to FMF diagnosis in patients with VUS.

Diagnosis and long-term outcome in dogs with acute onset intracranial signs.

OBJECTIVES: To investigate dogs with acute onset of intracranial signs suspected of stroke by primary veterinary clinicians, and establish possible differential diagnoses and long-term outcome. In addition, serum C-reactive protein and plasma cytokines were investigated as potential biomarkers of disease. MATERIALS AND METHODS: All cases were evaluated by neurologic examination, routine haematology and biochemistry and measurement of serum C-reactive protein, plasma cytokine concentrations (interleukin-2, -6, -8, -10, tumour necrosis factor) and low-field MRI. RESULTS: Primary veterinarians contacted the investigators with 85 suspected stroke cases. Only 20 met the inclusion criteria. Of these, two were diagnosed with ischaemic stroke. Other causes were idiopathic vestibular syndrome (n=6), brain tumour (n=5) and inflammatory brain disease (n=2); in five cases a precise diagnosis could not be determined. Median survival times were: brain tumour, 3 days, idiopathic vestibular syndrome, 315 days, ischaemic stroke, 365 days and inflammatory central nervous system (CNS) disease, 468 days. The median plasma concentrations of interleukin-2, -6, -8, -10 or tumour necrosis factor were not significantly increased in any of the diagnosis groups compared to healthy controls. Serum C-reactive protein was higher in dogs with brain tumours and inflammatory brain disease but not above the upper bound of the reference interval. CLINICAL SIGNIFICANCE: Dogs that present with acute onset intracranial disease may have ischaemic stroke but are more likely to have other causes. Many dogs with such acute onset of neurological dysfunction (brain tumours excluded) may recover within a couple of weeks despite their initial severe clinical appearance.

Nuclear translocation of endonuclease G in degenerating neurons after permanent middle cerebral artery occlusion in mice.

Endonuclease G (EndoG) is a mitochondrial enzyme, known to be involved in caspase-independent cell death following translocation to the cellular nucleus. Nuclear translocation of EndoG has been observed in the ischemic area following transient occlusion of the middle cerebral artery (MCA) in mice, but not after permanent MCA occlusion. In this study we investigated the cellular and temporal expression of EndoG in infarcted cortex during the first 24 h after permanent MCA occlusion in mice, using immunohistochemistry, quantitative rt-PCR and cell specific immunoflourescence markers. EndoG translocated from the cytoplasm to the nucleus as early as 4 h and with a significant increase in the number of EndoG positive nuclei at 12 and 24 h after MCA occlusion. Nuclear translocation of EndoG was observed in degenerating NeuN positive neurons that were evenly distributed throughout the developing infarct. Translocation of EndoG was supported by unaltered EndoG mRNA levels. EndoG was neither expressed in GFAP positive astrocytes nor in CD11b positive microglia/macrophages. In contrast, CD11b positive microglia, but not infiltrating CD11b positive bone marrow-derived macrophages, were shown to express activated caspase-3. The translocation of EndoG to the nucleus of neurons in the infarct implicates EndoG in ischemic neuronal degeneration after permanent MCA occlusion in mice. Increased knowledge about EndoG involvement in ischemic neuronal cell death in mice might offer a promise to control processes involved in neuronal cell death pathways in stroke.

Microglia and macrophages express tumor necrosis factor receptor p75 following middle cerebral artery occlusion in mice.

The proinflammatory and potential neurotoxic cytokine tumor necrosis factor (TNF) is produced by activated CNS resident microglia and infiltrating blood-borne macrophages in infarct and peri-infarct areas following induction of focal cerebral ischemia. Here, we investigated the expression of the TNF receptors, TNF-p55R and TNF-p75R, from 1 to 10 days following permanent occlusion of the middle cerebral artery in mice. Using quantitative polymerase chain reaction (PCR), we observed that the relative level of TNF-p55R mRNA was significantly increased at 1-2 days and TNF-p75R mRNA was significantly increased at 1-10 days following arterial occlusion, reaching peak values at 5 days, when microglial-macrophage CD11b mRNA expression was also increased. In comparison, the relative level of TNF mRNA was significantly increased from 1 to 5 days, with peak levels 1 day after arterial occlusion. In situ hybridization revealed mRNA expression of both receptors in predominantly microglial- and macrophage-like cells in the peri-infarct and subsequently in the infarct, and being most marked from 1 to 5 days. Using green fluorescent protein-bone marrow chimeric mice, we confirmed that TNF-p75R was expressed in resident microglia and blood-borne macrophages located in the peri-infarct and infarct 1 and 5 days after arterial occlusion, which was supported by Western blotting. The data show that increased expression of the TNF-p75 receptor following induction of focal cerebral ischemia in mice can be attributed to expression in activated microglial cells and blood-borne macrophages.

A quantitative in situ hybridization and polymerase chain reaction study of microglial-macrophage expression of interleukin-1beta mRNA following permanent middle cerebral artery occlusion in mice.

Interleukin-1beta (IL-1beta) is known to play a central role in ischemia-induced brain damage in rodents. In comparison to the rat, however, the available data on the cellular synthesis of IL-1beta mRNA and protein in the mouse are very limited. Here, we report on the time profile, the topography and the quantitative, cellular expression of IL-1beta mRNA in mice subjected to permanent occlusion of the distal middle cerebral artery (MCA). The in situ hybridization analysis showed that IL-1beta mRNA was expressed during the first post-surgical hour in a small number of high-expressing macrophage-like cells, located in cortical layers I and II of the future infarct. At 2 h, a significant number of faintly labeled IL-1beta mRNA-expressing cells had appeared in the developing peri-infarct, and the number remained constant at 4 h and 6 h, when the hybridization signal began to distribute to the cellular processes. Quantitative PCR performed on whole hemispheres showed a significant 20-fold increase in the relative level of IL-1beta mRNA at 12 h and a highly significant 42-fold increase at 24 h, at which time single IL-1beta mRNA-expressing cells were supplemented by aggregates and perivascular infiltrates of intensely labeled IL-1beta mRNA-expressing cells. Immunohistochemistry and double immunohistochemical stainings in addition to combined in situ hybridization, confirmed that the intensely labeled IL-1beta mRNA-expressing and IL-1beta protein synthesizing cells predominantly were glial fibrillary acidic protein-immunonegative, macrophage associated antigen-1-immunopositive microglia-macrophages. By day 5 there was a dramatic decline in the relative level of IL-1beta mRNA in the ischemic hemisphere. In summary, the data provide evidence that permanent occlusion of the distal MCA in mice results in expression of IL-1beta mRNA and IL-1beta synthesis in spatially and temporally segregated subpopulations of microglia and macrophages.

A specific and sensitive method for visualization of tumor necrosis factor in the murine central nervous system.

We present here sensitive, simple and robust methods for detection of tumor necrosis factor (TNF) mRNA and TNF in histological sections and homogenates of brain tissue from mice subjected to focal cerebral ischemia or hippocampal axonal lesioning. Both types of lesions are characterized by induction of TNF synthesis in resident microglial cells, which in the ischemic lesions are supplemented by TNF synthesizing, blood-borne macrophages. In situ hybridization for TNF mRNA is performed using alkaline phosphatase-labelled oligodeoxynucleotide probes. These probes show excellent rendition of individual cells, and can successfully be combined with immunohistochemical procedures. We also describe a sensitive immunohistochemical method for detection of TNF, which can be combined with visualization of an additional antigen. The specificity of the histological procedures are confirmed by RT-PCR and Western blot analysis on homogenates prepared from microdissected brain regions. Advantages and disadvantages of the methods are discussed with emphasis on the specificity and sensitivity of the histological procedures. Our strategy for detection of TNF mRNA and protein provides a solid basis for clarifying the cellular synthesis, regulation and function of TNF in the normal, injured or diseased CNS. Furthermore, the methodology can readily be applied in studies of other cytokines and growth factors in the CNS.