Thrombin mutant W215A/E217A treatment improves neurological outcome and attenuates central nervous system damage in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a neuroinflammatory disease characterized by demyelination and axonal damage of the central nervous system. The pathogenesis of MS has also been linked to vascular inflammation and local activation of the coagulation system, resulting in perivascular fibrin deposition. Treatment of experimental autoimmune encephalomyelitis (EAE), a model of human MS, with antithrombotic and antiinflammatory activated protein C (APC) reduces disease severity. Since recombinant APC (Drotecogin alfa), originally approved for the treatment of severe sepsis, is not available for human MS studies, we tested the hypothesis that pharmacologic activation of endogenous protein C could likewise improve the outcome of EAE. Mice were immunized with murine myelin oligodendrocyte glycoprotein (MOG) peptides and at the onset of EAE symptoms, were treated every other day with either WE thrombin (25 µg/kg; i.v.), a selective recombinant protein C activator thrombin analog, or saline control. Mice were monitored for changes in disease score until euthanized for ex vivo analysis of inflammation. Administration of WE thrombin significantly ameliorated clinical severity of EAE, reduced inflammatory cell infiltration and demyelination, suppressed the activation of macrophages comprising the CD11b + population and reduced accumulation of fibrin (ogen) in the spinal cord. These data suggest that symptomatic MS may respond to a treatment strategy that involves temporal pharmacological enhancement of endogenous APC generation.

A novel HLA-DRα1-MOG-35-55 construct treats experimental stroke.

Chemoattraction of leukocytes into the brain after induction of middle cerebral artery occlusion (MCAO) increases the lesion size and worsens disease outcome. Our previous studies demonstrated that partial MHC class II constructs can reverse this process. However, the potential application of pMHC to human stroke is limited by the need to rapidly match recipient MHC class II with the ß1 domain of the pMHC construct. We designed a novel recombinant protein comprised of the HLA-DRα1 domain linked to MOG-35-55 peptide but lacking the ß1 domain found in pMHC and treated MCAO after 4 h reperfusion in humanized DR2 mice. Infarct volumes were quantified after 96 h reperfusion and immune cells from the periphery and CNS were evaluated for expression of CD74 and other cell surface, cytokine and pathway markers. This study demonstrates that four daily treatments with DRα1-MOG-35-55 reduced infarct size by 40 % in the cortex, striatum and hemisphere, inhibited the migration of activated CD11b+CD45high cells from the periphery to the brain and reversed splenic atrophy. Furthermore, DRα1-MOG-35-55 bound to CD74 on monocytes and blocked both binding and downstream signaling of macrophage migration inhibition factor (MIF) that may play a key role in infarct development. The novel DRα1-MOG-35-55 construct is highly therapeutic in experimental stroke and could be given to all patients at least 4 h after stroke onset without the need for tissue typing due to universal expression of DRα1 in humans.

Oestrogen modulates experimental autoimmune encephalomyelitis and interleukin-17 production via programmed death 1.

The mechanism by which oestrogens suppress experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, is only partially understood. We here demonstrate that treatment with 17beta-oestradiol (E(2)) in C57BL/6 mice boosted the expression of programmed death 1 (PD-1), a negative regulator of immune responses, in the CD4(+) FoxP3(+) regulatory T (Treg) cell compartment in a dose-dependent manner that correlated with the efficiency of EAE protection. Administration of E(2) at pregnancy levels but not lower concentrations also enhanced the frequency of Treg cells. Additionally, E(2) treatment drastically reduced the production of interleukin-17 (IL-17) in the periphery of immunized mice. However, E(2) treatment did not protect against EAE or suppress IL-17 production in PD-1 gene-deficient mice. Finally, E(2) failed to prevent Treg-deficient mice from developing spontaneous EAE. Taken together, our results suggest that E(2)-induced protection against EAE is mediated by upregulation of PD-1 expression within the Treg-cell compartment.

A synthetic androstene analogue inhibits collagen-induced arthritis in the mouse.

Dehydroepiandrosterone (DHEA), a precursor of immune-regulating hormones (IRH) including the androstenes, has attracted much interest over the last several decades because of its many antiaging, metabolic, and immune modulating effects. 5-Androstene-16alpha fluoro-17-one (fluasterone, also known as HE2500) is a synthetic androstene analogue that retains anti-inflammatory, antiproliferative, and immune-regulating activities of the parent molecule, but is nontoxic and practically devoid of androgenic or estrogenic side effects. In the present studies, we tested the ability of fluasterone to limit disease in the DBA mouse model of collagen-induced arthritis (CIA). We found that mice receiving injections of fluasterone displayed significant delay in onset, decrease in CIA peak score, and significant decrease of the daily mean clinical score. Benefit was associated with significant decreases in (1). bovine type II collagen (bCII)-specific IgG(1) and IgG(2a) antibody levels in serum; (2). production of TNF-alpha, IL-6, IFN-gamma, but not IL-10; (3). lymphocyte proliferative response to bCII protein; and (4). joint inflammation, erosion, and synovial proliferation as judged by histological analysis. This is the first study to report that an IRH can ameliorate ongoing disease in a CIA mouse model with relevance to RA and to correlate that finding with decreases in pro-inflammatory cytokines.