Motoki Ichikawa

Anti-IL-12 antibody prevents the development and progression of multiple sclerosis-like relapsing–remitting demyelinating disease in NOD mice induced with myelin oligodendrocyte glycoprotein peptide

Treatment with monoclonal anti-IL-12 antibody injected on day 0, 7 and 10 after immunization with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 in NOD mice resulted in significant suppression of the development and the severity of the chronic relapsing-remitting experimental autoimmune encephalomyelitis (EAE) both clinically and histologically. The spleen cells from anti-IL-12 antibody treated mice displayed markedly inhibited MOG35-55 specific proliferation and IFN-gamma production. MOG35-55 specific antibody production was enhanced by anti-IL-12 antibody treatment. These results suggest that IL-12 is critically involved in the pathogenesis of MOG-induced EAE and that antibody to IL-12 could be an effective therapeutic agent in the clinical treatment of autoimmune demyelinating diseases such as multiple sclerosis (MS).

Granulocyte macrophage-colony stimulating factor delays neutrophil apoptosis and primes its function through Ia-type phosphoinositide 3-kinase

Phosphoinositide 3‐kinases (PI3Ks) constitute a family of lipid kinases that regulate an array of fundamental cellular responses by neutrophils [polymorphonuclear leukocytes (PMN)]. p85α Gene‐disrupted mice were used to help accurately identify the physiological role of the PI3K isoform in PMN activation in the presence of granulocyte macrophage‐colony stimulating factor (GM‐CSF). PMN from the p85α−/− mice showed normal cellular motility, and the quantity of superoxide anion () produced by PMN upon stimulation with formyl‐Met‐Leu‐Phe did not significantly differ between p85α−/− and wild‐type mice under controlled conditions. In p85α−/− mice, the production by PMN was enhanced (primed) by GM‐CSF when stimulated with the chemotactic peptide but to a significantly lesser extent than in wild‐type mice. In addition, no major GM‐CSF‐dependent delay in apoptosis or activation of Akt protein phosphorylation by GM‐CSF was observed in the p85α−/− mice. In terms of targeting strategy, however, the mutation actually expressed a small amount of Ia‐type (p85α‐regulated) PI3K activity (partially abrogated) in the mice. These results demonstrate that Ia‐type PI3K plays a critical role in the enhancement of the GM‐CSF‐modulated function of PMN and in the PI3K/Akt pathway‐dependent delay of PMN apoptosis.

Hypercalcemia associated with all-trans-retinoic acid in the treatment of acute promyelocytic leukemia

Recent reports have described clinical benefits of all-trans-retinoic acid (ATRA) therapy for acute promyelocytic leukemia (APL). This paper describes severe hypercalcemia (serum calcium: 18.7 mg/dl) in association with ATRA treatment in a 14 year old girl with APL. Serum parathyroid hormone (PTH) concentrations were normal (0.21 ng/ml), which precludes the possibility of primary hyperparathyroidism or ectopic PTH secretion as a cause of the hypercalcemia. As for the factors which can accelerate mineral resorption, there were no apparent increases in the levels of PTH-related protein (PTH-rP), prostaglandins and vitamin D metabolites. In our in vitro experiment, ATRA did not stimulate the leukemic cells to produce PTH-rP. We speculate that ATRA, like PTH, may increase osteoclastic activity and induce hypercalcemia.

A rat model for investigation of bladder dysfunction associated with demyelinating disease resembling multiple sclerosis

Myelin basic protein (MBP) can be used as an antigen for inducing experimental allergic encephalomyelitis (EAE). In various studies, EAE animals have been used as an experimental model of demyelinating diseases. The aim of this study was to determine whether EAE, induced by MBP in rats, can be useful for investigation of bladder dysfunction associated with demyelinating disease. Female Lewis rats were used. In Study 1, the time course of behavioral and cystometric changes were observed consecutively after MBP sensitization. In Study 2, the correlations between behavioral, cystometric, and histologic abnormalities were studied. The degree of paralysis and histologic findings were evaluated. In Study 1, transient hind limb paralysis was observed in all rats. Cystometric findings were characterized by three different patterns: 1) detrusor areflexia (DA), 2) detrusor hyperactivity (DH), and 3) normal. Ten (77%) of the 13 rats given MBP showed bladder dysfunction, including DA (seven), DA/DH (two) and DH (one). Study 2 showed DA in 10 rats, DH in one, and normal findings in nine animals. The difference in degree of paralysis between the DA and the cystometrically normal animals was statistically significant (P < 0.01). The mean value of the degree of inflammation in the spinal cord (L6–S1) in the DA group was significantly (P < 0.05) higher than that in the cystometrically normal group. The degrees of paralysis and spinal inflammation were weakly correlated (R = 0.47, P = 0.05). The present rat model seems useful for studies of bladder dysfunction associated with spinal myelitis/demyelinating diseases. Neurourol. Urodynam. 19:689–699, 2000.

Plasma thrombin–antithrombin III complex is associated with the severity of experimental autoimmune encephalomyelitis

Previous studies have shown that activation of blood coagulation and fibrin depositions around CNS vessels are observed in animals with experimental autoimmune encephalomyelitis (EAE), which provides an animal model for human autoimmune demyelinating disorders. We examined the values of peripheral blood fibrinogen, thrombin-antithrombin III complex (TAT), fibrinolytic activity, and fibrin degradation products in Lewis rats with EAE to elucidate the role of the blood coagulation-fibrinolysis system in EAE. Plasma TAT values increased immediately prior to development of symptoms, and decreased according to the improvement of symptoms. There was significant correlation between TAT values and clinical scores of EAE; other markers were not correlated with the symptoms of EAE. These results suggest that plasma TAT levels are sensitive markers of the severity of EAE, and may be useful clinical indicators for the severity of human autoimmune demyelinating disorders.

Cerebellar ataxia in pediatric patients with Langerhans cell histiocytosis.

The pathogenetic mechanisms of the central nervous system (CNS) problems associated with Langerhans cell histiocytosis (LCH) are not well established. Effective treatment strategies for these CNS complications are not yet available, while diabetes insipidus, also associated with LCH, can be managed effectively. Three Japanese boys with LCH who developed cerebellar ataxia were evaluated. Similar pediatric cases from the literature are also discussed. All three patients initially developed multifocal LCH lesions during early childhood (age <3 years) that responded well to chemotherapy; however, two of the three patients later developed diabetes insipidus. Ataxia, associated with mild developmental delay, was noted in the patients between the ages of 4 to 8 years. Analysis of these three cases, along with previously reported cases, indicates that the median age of onset of LCH was 2.5 (range 0.1-6.5) years and the median age of onset of cerebellar lesions/ataxia was 7 (range 3.5-16.5) years. Although the incidence of cerebellar LCH involvement is low, delayed onset of CNS disease must be monitored during follow-up care of pediatric LCH patients. Brain magnetic resonance imaging is strongly recommended for early detection of cerebellar lesions, but it remains to be determined whether there are any therapeutic measures to prevent exacerbation of CNS disease.

Cytokine production profiles in chronic relapsing–remitting experimental autoimmune encephalomyelitis: IFN-γ and TNF-α are important participants in the first attack but not in the relapse

Multiple sclerosis (MS) is a chronic demyelinating disease often displaying a relapsing-remitting course of neurological manifestations that is mimicked by experimental autoimmune encephalomyelitis (EAE) in animal models of MS. In particular, NOD mice immunized with myelin oligodendrocyte glycoprotein peptide 35-55 develop chronic relapsing-remitting EAE (CREAE). To elucidate the mechanisms that cause MS relapse, we investigated the histopathology and cytokine production of spleen cells and mRNA expression levels in the central nervous system (CNS) of CREAE mice. During the first attack, inflammatory cell infiltration around small vessels and in the subarachnoid space was observed in the spinal cord. Spleen cell production and mRNA expression in the CNS of several cytokines, including IFN-γ, TNF-α, IL-6, IL-17, and CC chemokine ligand 2 (CCL2), were higher in CREAE mice than in controls. Afterwards, parenchymal infiltration and demyelination were observed histologically in the spinal cord and corresponded with the more severe clinical symptoms of the first and second relapses. IL-17 and CCL2, but not IFN-γ, TNF-α, or IL-6, were also produced by spleen cells during recurrences. Our results suggested that the immune mechanisms in relapses were different from those in the first attack for CREAE. Further investigation of CREAE mechanisms may provide important insights into successful therapies for human relapsing-remitting MS.

Prostacyclin Inhibits the Production of MMP-9 Induced by Phorbol Ester through Protein Kinase A Activation, but Does Not Affect the Production of MMP-2 in Human Cultured Mesangial Cells

Background/Aims: The imbalance between degradation and synthesis of the glomerular extracellular matrix (ECM) causes glomerular sclerosis in various types of glomerulonephritis. We investigated the effect of prostacyclin, which is an inflammatory mediator, on the production of matrix metalloproteinase (MMP)-9 and MMP-2 in human cultured mesangial cells. The synthesis of Jun proteins and Ets-1 proteins, which are related with MMP-9 gene, was also studied. Methods: The production of MMP-9 and MMP-2 was investigated by gelatin zymography. Western blotting was undertaken to analyze the protein synthesis of Jun and Ets-1. Results: Prostacyclin inhibited the production of MMP-9 induced by phorbol ester. The inhibitory effect by prostacyclin was reversed in part by the pretreatment with an inhibitor of protein kinase A, such as H-89. Forskolin also inhibited the production of MMP-9. The production of MMP-2 was constitutionally seen and was not influenced by prostacyclin and forskolin. The synthesis of Jun protein augmented by phorbol ester was suppressed by prostacyclin. Ets-1 protein was constitutionally synthesized and was not affected by phorbol ester and prostacyclin. Conclusion: Prostacyclin plays an important role in inflammatory glomerular disorders by regulating the metabolism of ECM. The production of MMP-9 and MMP-2 may be under the different control pathways.

Therapeutic effect of anti-αv integrin mAb on Theiler's murine encephalomyelitis virus-induced demyelinating disease

We examined the role of Notch ligand Delta-like 1 (Delta1) in the development of Theilers murine encephalomyelitis virus (TMEV)-induced demyelinating disease (TMEV-IDD). Blocking of Delta1 by anti-Delta1 monoclonal antibody (mAb) in the effector phase significantly suppressed the disease development of TMEV-IDD both clinically and histologically. The number of infiltrating inflammatory mononuclear cells in the spinal cords was also decreased in mice treated with anti-Delta1 mAb at the effector phase. Flow cytometric analysis of cytokine staining revealed that IFN-γ- or IL-4-producing CD4(+) splenocytes were significantly decreased in mice treated with anti-Delta1 mAb in the spleens, whereas IL-10-producing CD4(+) splenocytes were increased. Furthermore, IFN-γ-, TNF-α-, IL-4-, or IL-10-producing CD4(+) cells were decreased in spinal cords, and IL-17-producing CD4(+) cells were increased. These data suggest that Delta1 may play important roles in the development of TMEV-IDD and that antibodies to Delta1 could be used as a novel therapeutic treatment of demyelinating diseases such as human multiple sclerosis.

Brain-derived gangliosides suppress the chronic relapsing-remitting experimental autoimmune encephalomyelitis in NOD mice induced with myelin oligodendrocyte glycoprotein peptide.

Chronic relapsing-remitting experimental autoimmune encephalomyelitis (CREAE) induced with myelin oligodendrocyte glycoprotein peptides 35-55 (MOG(35-55)) in NOD mice was successfully treated with brain-derived gangliosides (GA). The GA treatment suppressed the development and severity of CREAE, both clinically and histologically. Spleen cells from the GA-treated mice displayed markedly inhibited levels of MOG(35-55) specific proliferation and interferon-gamma production. Delayed-type hypersensitivity reactions to MOG(35-55) were suppressed by the GA treatment. GA modulate various T cell effector functions in CREAE and may be an effective therapeutic agent for autoimmune demyelinating diseases such as multiple sclerosis.