Thymic Alterations in GM2 Gangliosidoses Model Mice

BACKGROUND: Sandhoff disease is a lysosomal storage disorder characterized by the absence of β-hexosaminidase and storage of GM2 ganglioside and related glycolipids. We have previously found that the progressive neurologic disease induced in Hexb(-/-) mice, an animal model for Sandhoff disease, is associated with the production of pathogenic anti-glycolipid autoantibodies. METHODOLOGY/PRINCIPAL FINDINGS: In our current study, we report on the alterations in the thymus during the development of mild to severe progressive neurologic disease. The thymus from Hexb(-/-) mice of greater than 15 weeks of age showed a marked decrease in the percentage of immature CD4(+)/CD8(+) T cells and a significantly increased number of CD4(+)/CD8(-) T cells. During involution, the levels of both apoptotic thymic cells and IgG deposits to T cells were found to have increased, whilst swollen macrophages were prominently observed, particularly in the cortex. We employed cDNA microarray analysis to monitor gene expression during the involution process and found that genes associated with the immune responses were upregulated, particularly those expressed in macrophages. CXCL13 was one of these upregulated genes and is expressed specifically in the thymus. B1 cells were also found to have increased in the thy mus. It is significant that these alterations in the thymus were reduced in FcRγ additionally disrupted Hexb(-/-) mice. CONCLUSIONS/SIGNIFICANCE: These results suggest that the FcRγ chain may render the usually poorly immunogenic thymus into an organ prone to autoimmune responses, including the chemotaxis of B1 cells toward CXCL13

Alterations in striatal dopamine catabolism precede loss of substantia nigra neurons in a mouse model of juvenile neuronal ceroid lipofuscinosis

Batten disease, or juvenile neuronal ceroid lipofuscinosis (JNCL), results from mutations in the CLN3 gene. This disorder presents clinically around the age of five years with visual deficits progressing to include seizures, cognitive impairment, motor deterioration, hallucinations, and premature death by the third to forth decade of life. The motor deficits include coordination and gait abnormalities, myoclonic jerks, inability to initiate movements, and spasticity. Previous work from our laboratory has identified an early reduction in catechol-O-methyltransferase (COMT), an enzyme responsible for the efficient degradation of dopamine. Alterations in the kinetics of dopamine metabolism could cause the accumulation of undegraded or unsequestered dopamine leading to the formation of toxic dopamine intermediates. We report an imbalance in the catabolism of dopamine in three month Cln3(-/-) mice persisting through nine months of age that may be causal to oxidative damage within the striatum at nine months of age. Combined with the previously reported inflammatory changes and loss of post-synaptic D1α receptors, this could facilitate cell loss in striatal projection regions and underlie a general locomotion deficit that becomes apparent at twelve months of age in Cln3(-/-) mice. This study provides evidence for early changes in the kinetics of COMT in the Cln3(-/-) mouse striatum, affecting the turnover of dopamine, likely leading to neuron loss and motor deficits. These data provide novel insights into the basis of motor deficits in JNCL and how alterations in dopamine catabolism may result in oxidative damage and localized neuronal loss in this disorder

Immunosuppression alters disease severity in juvenile Batten disease mice

Autoantibodies to brain proteins are present in Juvenile Neuronal Ceroid Lipofuscinosis (Batten disease) patients and in the Cln3(-/-) mouse model of this disease, suggesting an autoimmune component to pathogenesis. Using genetic or pharmaceutical approaches to attenuate this immune response in Cln3(-/-) mice, we demonstrate decreased neuroinflammation, decreased deposition of immunoglobulin G in the brain and protection of vulnerable neuron populations. Moreover, immune suppression results in a significant improvement in motor performance providing for the first plausible therapeutic approach for juvenile Batten disease. (C) 2010 Elsevier B.V. All rights reserved

Immunosuppression alters disease severity in juvenile Batten disease mice

Autoantibodies to brain proteins are present in Juvenile Neuronal Ceroid Lipofuscinosis (Batten disease) patients and the Cln3(−/−) mouse model of this disease, suggesting an autoimmune component to pathogenesis. Using genetic or pharmaceutical approaches to attenuate this immune response in Cln3(−/−) mice, we demonstrate decreased neuroinflammation, decreased deposition of Immunoglobulin G in the brain and protection of vulnerable neuron populations. Moreover, immune suppression results in a significant improvement in motor performance providing for the first plausible therapeutic approach for juvenile Batten disease

Juvenile Neuronal Ceroid Lipofuscinoses

Juvenile neuronal ceroid lipofuscinoses (JNCL) is the most common type of the neuronal ceroid lipofuscinoses (NCLs), a group of pediatric neurodegenerative diseases. In this chapter the genetic and biochemical basis, pathogenesis, clinical features, histopathological features, diagnosis and therapeutic strategies of the JNCL are reviewed. The premature death of the patients and subnormal life quality are inevitable due to the lack of understanding of pathogenesis and limitation in treatment. Hence we are still a long way to conquer the disease.PubMed0138-4272