Showing papers by "Tim Magnus published in 2016"
TL;DR: The results show that nanobody technology can generate potent, specific therapeutics against ion channels, confirm P2x7 as a therapeutic target for inflammatory disorders, and characterize a potent new drug candidate that targets P2X7.
Abstract: Ion channels are desirable therapeutic targets, yet ion channel–directed drugs with high selectivity and few side effects are still needed. Unlike small-molecule inhibitors, antibodies are highly selective for target antigens but mostly fail to antagonize ion channel functions. Nanobodies—small, single-domain antibody fragments—may overcome these problems. P2X7 is a ligand-gated ion channel that, upon sensing adenosine 5′-triphosphate released by damaged cells, initiates a proinflammatory signaling cascade, including release of cytokines, such as interleukin-1β (IL-1β). To further explore its function, we generated and characterized nanobodies against mouse P2X7 that effectively blocked (13A7) or potentiated (14D5) gating of the channel. Systemic injection of nanobody 13A7 in mice blocked P2X7 on T cells and macrophages in vivo and ameliorated experimental glomerulonephritis and allergic contact dermatitis. We also generated nanobody Dano1, which specifically inhibited human P2X7. In endotoxin-treated human blood, Dano1 was 1000 times more potent in preventing IL-1β release than small-molecule P2X7 antagonists currently in clinical development. Our results show that nanobody technology can generate potent, specific therapeutics against ion channels, confirm P2X7 as a therapeutic target for inflammatory disorders, and characterize a potent new drug candidate that targets P2X7.
130 citations
TL;DR: Dendritic cells are professional antigen presenting cells that constantly survey the environment acting as sentinels of the immune system, including in the CNS, and the literature reporting DCs in the inflamed brain in disease conditions and corresponding animal models is reviewed.
61 citations
TL;DR: Intracellular IL-17 in CSF cells is potentially useful in discriminating cerebral vasculitis as a rare cause in patients presenting with ischemic stroke.
Abstract: Objective: To explore the possibility of using interleukin-17 (IL-17) production by CD4+ T cells in the CSF as a potential biomarker for cerebral vasculitis in stroke patients. Methods: In this consecutive case study, we performed prospective analysis of CSF and blood in patients admitted to a university medical center with symptoms of stroke and suspected cerebral vasculitis. Flow cytometry was performed for intracellular detection of inflammatory cytokines in peripheral blood lymphocytes and expanded T cells from CSF. Results: CSF CD4+ lymphocytes from patients with cerebral vasculitis showed significantly higher levels of the proinflammatory cytokine IL-17 compared to patients with stroke not due to vasculitis or with other, noninflammatory neurologic diseases. There was no difference in the production of interferon-γ in the CSF and no overall differences in the relative frequencies of peripheral immune cells. Conclusions: Intracellular IL-17 in CSF cells is potentially useful in discriminating cerebral vasculitis as a rare cause in patients presenting with ischemic stroke. Classification of evidence: This study provides Class II evidence that an increased proportion of IL-17-producing CD4+ cells in CSF of patients presenting with stroke symptoms is indicative of cerebral vasculitis (sensitivity 73%, 95% confidence interval [CI] 39–94%; specificity 100%, 95% CI 74%–100%).
22 citations
TL;DR: This case illustrates an uncommon clinical picture of a PACNS and points to shortcomings of the current histopathologic criteria if only very small vessels are involved, as well as highlighting the diverse clinical manifestations of the disease.
4 citations
TL;DR: Findings suggest that the loss of venous contrast is related to an increase in CBF secondary to severe anemia related to HUS and may be related to the acute onset of anemia.
Abstract: Background and Purpose
Conventional magnetic resonance imaging (MRI) of patients with hemolytic uremic syndrome (HUS) and neurological symptoms performed during an epidemic outbreak of Escherichia coli O104:H4 in Northern Europe has previously shown pathological changes in only approximately 50% of patients. In contrast, susceptibility-weighted imaging (SWI) revealed a loss of venous contrast in a large number of patients. We hypothesized that this observation may be due to an increase in cerebral blood flow (CBF) and aimed to identify a plausible cause.
Materials and Methods
Baseline 1.5T MRI scans of 36 patients (female, 26; male, 10; mean age, 38.2±19.3 years) were evaluated. Venous contrast was rated on standard SWI minimum intensity projections. A prototype four-dimensional (time resolved) magnetic resonance angiography (4D MRA) assessed cerebral hemodynamics by global time-to-peak (TTP), as a surrogate marker for CBF. Clinical parameters studied were hemoglobin, hematocrit, creatinine, urea levels, blood pressure, heart rate, and end-tidal CO2.
Results
SWI venous contrast was abnormally low in 33 of 36 patients. TTP ranged from 3.7 to 10.2 frames (mean, 7.9 ± 1.4). Hemoglobin at the time of MRI (n = 35) was decreased in all patients (range, 5.0 to 12.6 g/dL; mean, 8.2 ± 1.4); hematocrit (n = 33) was abnormally low in all but a single patient (range, 14.3 to 37.2%; mean, 23.7 ± 4.2). Creatinine was abnormally high in 30 of 36 patients (83%) (range, 0.8 to 9.7; mean, 3.7 ± 2.2). SWI venous contrast correlated significantly with hemoglobin (r = 0.52, P = 0.0015), hematocrit (r = 0.65, P < 0.001), and TTP (r = 0.35, P = 0.036). No correlation of SWI with blood pressure, heart rate, end-tidal CO2, creatinine, and urea level was observed. Findings suggest that the loss of venous contrast is related to an increase in CBF secondary to severe anemia related to HUS. SWI contrast of patients with pathological conventional MRI findings was significantly lower compared to patients with normal MRI (mean SWI score, 1.41 and 2.05, respectively; P = 0.04). In patients with abnormal conventional MRI, mean TTP (7.45), mean hemoglobin (7.65), and mean hematocrit (22.0) were lower compared to patients with normal conventional MRI scans (mean TTP = 8.28, mean hemoglobin = 8.63, mean hematocrit = 25.23).
Conclusion
In contrast to conventional MRI, almost all patients showed pathological changes in cerebral hemodynamics assessed by SWI and 4D MRA. Loss of venous contrast on SWI is most likely the result of an increase in CBF and may be related to the acute onset of anemia. Future studies will be needed to assess a possible therapeutic effect of blood transfusions in patients with HUS and neurological symptoms.
2 citations
TL;DR: Quantitative T2* imaging might be a feasible tool to indicate change of oxygenation in acute stroke imaging, without administration of contrast agent, in the histologically defined infarct core and surrounding surviving tissue.
2 citations
TL;DR: This meeting report summarizes the many diverse presentations and the new preclinical to clinical neurology research data that were shared by the participants at the meeting.
Abstract: From October 30–November 1, 2015, the 7th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. Seventy doctoral students and postdocs from over 25 different groups working in German and Swiss University Hospitals or Research Institutes attended the meeting to discuss their latest experiments and findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. This meeting report summarizes the many diverse presentations and the new preclinical to clinical neurology research data that were shared by the participants at the meeting.
1 citations
TL;DR: It is demonstrated that Mincle lacks widespread expression in the brain, but is specifically associated with macrophages resident in the perivascular niche, which implicate Mincle in the initiation, extent and severity of local responses to ischemic injury in thebrain, but not peripheral tissues.
Abstract: Mincle is a C-type lectin known to play a role in innate immune responses to sterile inflammation, but its contribution to pathologies following an ischemic or traumatic injury is not well understood. In the current study we demonstrate a key role for Mincle in ischemic (i.e. transient middle cerebral artery occlusion) but not traumatic central nervous system injury; absence of Mincle also did not significantly alter the extent of tissue damage or functional outcome in peripheral models of ischemic tissue injury. In the stroke model mice lacking Mincle displayed significantly improved functional outcome from focal cerebral ischemia. The functional improvements in Mincle KO animals were accompanied by reduced infiltration of neutrophils and lower levels of proinflammatory cytokines in recruited peripheral blood cells. Bone marrow chimera experiments revealed that presence of Mincle in the central nervous system, but not peripheral immune cells, was the critical regulator of a poor outcome following transient focal cerebral ischemia, however we exclude a direct role for Mincle in microglia or neural activation. We demonstrate that Mincle lacks widespread expression in the brain, but is specifically associated with macrophages resident in the perivascular niche. These findings implicate Mincle in the initiation, extent and severity of local responses to ischemic injury in the brain, but not peripheral tissues. Mincle signalling therefore offers a novel therapeutic target in the quest to limit damage after stroke. Sources of support: Australian National Health & Medical Research Council [1057846, 1060538 and Fellowship to NAR], SpinalCure Australia (Career Development Fellowship to MJR), the Australian Research Council, the State Government of Victoria, the Australian Government and The University of Queensland.
1 citations