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Glucocorticoids (GCs) represent the standard treatment for acute disease bouts in multiple sclerosis (MS) patients, for which methylprednisolone (MP) pulse therapy is the most frequently used protocol. Here, we compared the efficacy of therapeutic and preventive MP application in MOG35-55-induced experimental autoimmune encephalomyelitis (EAE) in C57Bl/6 mice. When administered briefly after the onset of the disease, MP efficiently ameliorated EAE in a dose-dependent manner. Surprisingly, MP administration around the time of immunization was contraindicated as it even increased leukocyte infiltration into the CNS and worsened the disease symptoms. Our analyses suggest that in the latter case an incomplete depletion of peripheral T cells by MP triggers homeostatic proliferation, which presumably results in an enhanced priming of autoreactive T cells and causes an aggravated disease course. Thus, the timing and selection of a particular GC derivative require careful consideration in MS therapy. [ABSTRACT FROM AUTHOR]

Background: Dissociating glucocorticoid receptor (GR) ligands hold great promise for treating inflammatory disorders since it is assumed that they exert beneficial activities mediated by transrepression but avoid adverse effects of GR action requiring transactivation. Here we challenged this paradigm by investigating 2-(4-acetoxyphenyl)-2-chloro-N-methylethylammonium chloride (CpdA), a dissociating non-steroidal GR ligand, in the context of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Methodology/Principal Findings: CpdA inhibited pro-inflammatory mediators in myelin-specific T cells and fibroblasts in a GR-dependent manner while gene activation was abolished. However, it also induced massive apoptosis in various cell types even in the absence of the GR by engaging a Bcl-2- and caspase-dependent pathway. ¹H NMR spectroscopy corroborated these findings by revealing that CpdA dissolved in buffered solutions rapidly decomposes into aziridine intermediates known to act as alkylating pro-apoptotic agents. Importantly, the dichotomy of CpdA action also became evident in vivo. Administration of high-dose CpdA to mice was lethal while treatment of EAE with low to intermediate amounts of CpdA dissolved in water significantly ameliorated the disease. The beneficial effect of CpdA required expression of the GR in T cells and was achieved by down regulating LFA-1 and CD44 on peripheral Th cells and by repressing IL-17 production. Conclusions/Significance: CpdA has significant therapeutic potential although adverse effects severely compromise its application in vivo. Hence, non-steroidal GR ligands require careful analysis prior to their translation into new therapeutic concepts. [ABSTRACT FROM AUTHOR]

Glucocorticoids (GCs) are widely used to treat acute relapses of multiple sclerosis (MS). In this study, we demonstrate that liposomal encapsulation augments the therapeutic potency of GCs as they ameliorate experimental autoimmune encephalomyelitis (EAE) to the same extent as free GC, but at strongly reduced dosage and application frequency. Importantly, this is accompanied by an altered mode of action. Unlike free GCs, which mainly target T lymphocytes during EAE therapy, liposomal GCs only marginally affect T cell apoptosis and function. In contrast, liposomal GCs efficiently repress proinflammatory macrophage functions and upregulate anti-inflammatory genes associated with the alternatively activated M2 phenotype. The GC receptor (GR) per se is indispensable for the therapeutic efficacy of liposomal GC. In contrast to free GCs, however, the individual deletion of the GR either in T cells or myeloid cells has little effect on the efficacy of liposomal GCs in the treatment of EAE. Only the combined deletion of the GR in both cellular compartments markedly compromises the therapeutic effect of liposomal GCs on disease progression. In conclusion, encapsulation of GC does not only enhance their efficacy in the treatment of EAE but also alters their target cell specificity and their mode of action compared with free GCs. [ABSTRACT FROM AUTHOR]