Andreas Steinbrecher

Targeting Dipeptidyl Peptidase IV (CD26) Suppresses Autoimmune Encephalomyelitis and Up-Regulates TGF-β1 Secretion In Vivo

CD26 or dipeptidyl peptidase IV (DP IV) is expressed on various cell types, including T cells. Although T cells can receive activating signals via CD26, the physiological role of CD26/DP IV is largely unknown. We used the reversible DP IV inhibitor Lys[Z(NO2)]-pyrrolidide (I40) to dissect the role of DP IV in experimental autoimmune encephalomyelitis (EAE) and to explore the therapeutic potential of DP IV inhibition for autoimmunity. I40 administration in vivo decreased and delayed clinical and neuropathological signs of adoptive transfer EAE. I40 blocked DP IV activity in vivo and increased the secretion of the immunosuppressive cytokine TGF-β1 in spinal cord tissue and plasma during acute EAE. In vitro, while suppressing autoreactive T cell proliferation and TNF-α production, I40 consistently up-regulated TGF-β1 secretion. A neutralizing anti-TGF-β1 Ab blocked the inhibitory effect of I40 on T cell proliferation to myelin Ag. DP IV inhibition in vivo was not generally immunosuppressive, neither eliminating encephalitogenic T cells nor inhibiting T cell priming. These data suggest that DP IV inhibition represents a novel and specific therapeutic approach protecting from autoimmune disease by a mechanism that includes an active TGF-β1-mediated antiinflammatory effect at the site of pathology.

Adult medulloblastoma: prognostic factors and response to therapy at diagnosis and at relapse.

AbstractAdult medulloblastoma is a rare tumor with few retrospective studies published so far. The role of adjuvant chemotherapy or chemotherapy at relapse is unclear. This study reports therapy and outcome in all adult (≥ 16 years old) medulloblastoma (n = 34) and supratentorial primitive neuroectodermal tumor (PNET) patients (n = 2) treated in 2 neuro–oncological centers between 1976 and 2002. The median age was 24.5 years (range 16–76). After resection, 16 patients were treated with craniospinal radiotherapy alone, 20 patients also received adjuvant chemotherapy (8 vincristine, CCNU, cisplatin; 7 methotrexate alone or methotrexate/vincristine–based polychemotherapy; 5 other protocols). Median survival in the whole cohort was 126 months (2+ – 200+ months). Five–year and 10–year survival rates were 79 % and 56%. Adjuvant chemotherapy was associated with a non–significant trend to prolonged survival (relative risk (RR) 1.89; p = 0.068). The median progression–free survival (PFS) after primary therapy was 83 months. At relapse, 10 of 12 evaluable patients achieved a complete response upon second–line therapy. The median survival times from first (n = 17) and second relapse (n = 9) were 21 months (0–67+ months; 5/17 without second relapse) and 20 months (1–29 months). Cox regression analysis revealed the infiltration of the floor of the 4th ventricle at diagnosis as the only therapy–independent prognostic factor (RR 0.48; p = 0.03). In conclusion, adjuvant chemotherapy may prolong survival in adult medulloblastoma patients. Moreover, second–line therapy may be beneficial for these patients. As in pediatric medulloblastoma patients, primary infiltration of the floor of the 4th ventricle indicates a poor prognosis.

Low-Dose Chemotherapy in Combination with COX-2 Inhibitors and PPAR-Gamma Agonists in Recurrent High-Grade Gliomas : A Phase II Study

Objectives: Combined treatment approaches targeting tumor as well as other cells contributing to tumor progression may control chemorefractory malignancies. Methods: A phase II trial was initiated to analyze the activity of continuously administered pioglitazone and rofecoxib combined with low-dose chemotherapy (capecitabine or temozolomide) in patients with high-grade gliomas (glioblastoma or anaplastic glioma). Results: Fourteen patients were evaluable for response and toxicity. Major side effects were palmoplantar erythema, edema and motor neuropathy grade 3. Disease stabilizations lasting longer than 3 months were noted in 4 of 14 patients (29%). Clinical responses did not correspond to immunohistochemical staining for cyclooxygenase 2, peroxisome proliferator-activated receptor-γ and CD31. Discussion: The study demonstrates that this novel regimen is moderately active and well tolerated in patients with high-grade gliomas. As a comparably small proportion of patients responded, the regimen might only be suitable for a subset of highly selected patients.

Targeting fibroblast growth factor-inducible-14 signaling protects from chronic relapsing experimental autoimmune encephalomyelitis

The TNF-related weak inducer of apoptosis (TWEAK) is a TNF family member mediating proinflammatory effects by its receptor fibroblast growth factor-inducible-14 (Fn14). We studied the role of TWEAK/Fn14 in experimental autoimmune encephalomyelitis (EAE) by protein vaccination with TWEAK and Fn14 and recombinant TWEAK-DNA, respectively. TWEAK-DNA vaccination worsened the clinical course of EAE and increased central nervous system (CNS) inflammation. TWEAK increased the secretion of CCL2 [monocyte chemotactic protein-1 (MCP-1)] by CNS endothelial cells and astrocytes in vitro, suggesting CCL2 as a critical mediator of TWEAKs proinflammatory effects. Vaccination with the extracellular domain of TWEAK or with Fn14 resulted in the induction of specific inhibitory antibodies and an amelioration of EAE signs in two different models in rats and mice. Spinal cord inflammatory infiltrates were significantly diminished. Purified IgG from TWEAK- or Fn14-vaccinated rats prevented TWEAK-induced production of CCL2 by endothelial cells. Blocking Fn14 signaling represents a novel approach with potential for the treatment of CNS autoimmunity.

Smad7 in T cells drives T helper 1 responses in multiple sclerosis and experimental autoimmune encephalomyelitis.

Autoreactive CD4+ T lymphocytes play a vital role in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis. Since the discovery of T helper 17 cells, there is an ongoing debate whether T helper 1, T helper 17 or both subtypes of T lymphocytes are important for the initiation of autoimmune neuroinflammation. We examined peripheral blood CD4+ cells from patients with active and stable relapsing–remitting multiple sclerosis, and used mice with conditional deletion or over-expression of the transforming growth factor-β inhibitor Smad7, to delineate the role of Smad7 in T cell differentiation and autoimmune neuroinflammation. We found that Smad7 is up-regulated in peripheral CD4+ cells from patients with multiple sclerosis during relapse but not remission, and that expression of Smad7 strongly correlates with T-bet, a transcription factor defining T helper 1 responses. Concordantly, mice with transgenic over-expression of Smad7 in T cells developed an enhanced disease course during experimental autoimmune encephalomyelitis, accompanied by elevated infiltration of inflammatory cells and T helper 1 responses in the central nervous system. On the contrary, mice with a T cell-specific deletion of Smad7 had reduced disease and central nervous system inflammation. Lack of Smad7 in T cells blunted T cell proliferation and T helper 1 responses in the periphery but left T helper 17 responses unaltered. Furthermore, frequencies of regulatory T cells were increased in the central nervous system of mice with a T cell-specific deletion and reduced in mice with a T cell-specific over-expression of Smad7. Downstream effects of transforming growth factor-β on in vitro differentiation of naïve T cells to T helper 1, T helper 17 and regulatory T cell phenotypes were enhanced in T cells lacking Smad7. Finally, Smad7 was induced during T helper 1 differentiation and inhibited during T helper 17 differentiation. Taken together, the level of Smad7 in T cells determines T helper 1 polarization and regulates inflammatory cellular responses. Since a Smad7 deletion in T cells leads to immunosuppression, Smad7 may be a potential new therapeutic target in multiple sclerosis.

RNOP-09: Pegylated liposomal doxorubicine and prolonged temozolomide in addition to radiotherapy in newly diagnosed glioblastoma - a phase II study

BackgroundAlthough Temozolomide is effective against glioblastoma, the prognosis remains dismal and new regimens with synergistic activity are sought for.MethodsIn this phase-I/II trial, pegylated liposomal doxorubicin (Caelyx™, PEG-Dox) and prolonged administration of Temozolomide in addition to radiotherapy was investigated in 63 patients with newly diagnosed glioblastoma. In phase-I, PEG-Dox was administered in a 3-by-3 dose-escalation regimen. In phase-II, 20 mg/m2 PEG-Dox was given once prior to radiotherapy and on days 1 and 15 of each 28-day cycle starting 4 weeks after radiotherapy. Temozolomide was given in a dose of 75 mg/m2 daily during radiotherapy (60 Gy) and 150-200 mg/m2 on days 1-5 of each 28-day cycle for 12 cycles or until disease progression.ResultsThe toxicity of the combination of PEG-Dox, prolonged administration of Temozolomide, and radiotherapy was tolerable. The progression free survival after 12 months (PFS-12) was 30.2%, the median overall survival was 17.6 months in all patients including the ones from Phase-I. None of the endpoints differed significantly from the EORTC26981/NCIC-CE.3 data in a post-hoc statistical comparison.ConclusionTogether, the investigated combination is tolerable and feasible. Neither the addition of PEG-Dox nor the prolonged administration of Temozolomide resulted in a meaningful improvement of the patients outcome as compared to the EORTC26981/NCIC-CE.3 dataTrial registrationclinicaltrials.gov NCT00944801.

Delayed humoral immunity in a patient with severe tick-borne encephalitis after complete active vaccination.

Tick-borne encephalitis virus (TBEV) is a common cause of viral encephalitis in parts of Central and Eastern Europe. Active immunization results in a high rate of seroconversion and is the most effective measure of decreasing the incidence of tick-borne encephalitis (TBE). Currently, booster vaccinations are recommended every 3 years after completion of primary immunization. However, titers of neutralizing antibodies decline with time after vaccination and with age and thus may be insufficient to protect from disease in the elderly. We report on a 54-year-old patient who had received his last booster vaccination 3 years before developing a severe TBE with delayed induction and longterm persistence of anti-TBEV-IgM-antibodies.

Novel role for SLPI in MOG-induced EAE revealed by spinal cord expression analysis

BackgroundExperimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte protein (MOG) in female Dark Agouti (DA) rats is a chronic demyelinating animal model of multiple sclerosis (MS). To identify new candidate molecules involved in the evolution or repair of EAE-lesions we used Affymetrix oligonucleotide microarrays to compare the spinal cord transcriptome at the peak of EAE, during remission and at the first relapse with healthy DA rats.MethodsUntreated DA rats and DA rats immunised with MOG protein were sacrificed at defined time points. Total RNA was isolated from spinal cord tissue and used for hybridization of Affymetrix rat genome arrays RG U34 A-C. Selected expression values were confirmed by RealTime PCR.Adult neural stem cells were incubated with recombinant secretory leukocyte protease inhibitor (SLPI). Proliferation was assessed by BrdU incorporation, cyclin D1 and HES1 expression by RealTime PCR, cell differentiation by immunofluorescence analysis and IkappaBalpha degradation by Western blot.ResultsAmong approximately 26,000 transcripts studied more than 1,100 were differentially regulated. Focussing on functional themes, we noticed a sustained downregulation of most of the transcripts of the cholesterol biosynthesis pathway. Furthermore, we found new candidate genes possibly contributing to regenerative processes in the spinal cord. Twelve transcripts were solely upregulated in the recovery phase, including genes not previously associated with repair processes. Expression of SLPI was upregulated more than hundredfold during EAE attack. Using immunohistochemistry, SLPI was identified in macrophages, activated microglia, neuronal cells and astrocytes. Incubation of adult neural stem cells (NSC) with recombinant SLPI resulted in an increase of cell proliferation and of differentiation towards oligodendrocytes. These processes were paralleled by an upregulation of the cell-cycle promotor cyclin D1 and a suppression of the cell differentiation regulator HES1. Finally, SLPI prevented the degradation of IkappaBalpha, which may explain the suppression of the cell differentiation inhibitor HES1 suggesting a possible mechanism of oligodendroglial differentiation.ConclusionWe identified novel features of gene expression in the CNS during EAE, in particular the suppression of genes of cholesterol biosynthesis and a strong upregulation of SLPI, a gene which is for the first time associated with autoimmune inflammation. The capacity of SLPI to increase proliferation of adult NSC and of oligodendroglial differentiation suggests a novel role for SLPI in the promotion of tissue repair, beyond its known functions in the prevention of tissue damages by protease inhibition damage and modulation of inflammatory reactions.

The Decoy Receptor 3 (DcR3, TNFRSF6B) suppresses Th17 immune responses and is abundant in human cerebrospinal fluid

The Decoy Receptor 3 (DcR3) is known to compete with the signalling receptors of the Fas ligand (FasL), LIGHT and the TNF-like molecule 1A (TL1A). The primary aim of this study was to provide insights into the role of DcR3 in the modulation of myelin-specific encephalitogenic autoimmune T cell responses. Treatment of PLP-specific lymph node cells with DcR3.Fc protein resulted in a suppression of IFN-g and IL-17, in a reduced proportion of Th17 cells and in a decrease of encephalitogenicity. The Th17 response promoting cytokines IL-6 and IL-23 were suppressed by DcR3.Fc as well. DcR3.Fc-treatment of CD4+ T cells with a defective FasL did not influence the production of IL-17 indicating that DcR3 suppresses IL-17 production by disruption of Fas-FasL interactions. We identified high concentrations of DcR3 in the cerebrospinal fluid (CSF) of patients with various neurological disease states while almost no DcR3 was detected in corresponding serum samples. In conclusion, DcR3 modulates CNS-autoimmunity by interfering with Th17 responses via blockade of Fas-FasL interaction. The anti-inflammatory properties and high DcR3 concentrations in the CSF warrant further investigations in the expression pattern and the function of DcR3 within the CNS.

Intraventricular cytarabine in a case of idiopathic hypertrophic pachymeningitis

Idiopathic hypertrophic chronic pachymeningitis (IHCP) is characterised by inflammatory fibrotic thickening of the dura mater. Long term management is controversial. A 28 year old man with craniospinal IHCP and prominent lymphocytic meningitis is reported. Cerebrospinal fluid and histological examination suggested a CD4+ T cell driven process and B cell stimulation. After surgical, tuberculostatic, and immunosuppressive treatment failed to control the progressive meningeal hypertrophy, causing severe headache and neurological disability, the disease process eventually abated with intraventricular cytarabine treatment.