Sphingolipid abnormalities in encephalomyeloradiculoneuropathy (EMRN) are associated with an anti-neutral glycolipid antibody

Accumulating evidence suggests that various sphingolipids and glycosphingolipids can act as mediators for inflammation or signaling molecules in the nervous system. In this article, we explore the molecular basis of a new neuroinflammatory disorder called encephalomyeloradiculoneuropathy (EMRN), which affects the brain, spinal cord, and peripheral nerves; in particular, we discuss whether glycolipid and sphingolipid dysmetabolism is present in patients with this disorder. This review will focus on the pathognomonic significance of sphingolipid and glycolipid dysmetabolism for the development of EMRN and the possible involvement of inflammation in the nervous system.

Exploring Pro-Inflammatory Immunological Mediators: Unraveling the Mechanisms of Neuroinflammation in Lysosomal Storage Diseases

Lysosomal storage diseases are a group of rare and ultra-rare genetic disorders caused by defects in specific genes that result in the accumulation of toxic substances in the lysosome. This excess accumulation of such cellular materials stimulates the activation of immune and neurological cells, leading to neuroinflammation and neurodegeneration in the central and peripheral nervous systems. Examples of lysosomal storage diseases include Gaucher, Fabry, Tay–Sachs, Sandhoff, and Wolman diseases. These diseases are characterized by the accumulation of various substrates, such as glucosylceramide, globotriaosylceramide, ganglioside GM2, sphingomyelin, ceramide, and triglycerides, in the affected cells. The resulting pro-inflammatory environment leads to the generation of pro-inflammatory cytokines, chemokines, growth factors, and several components of complement cascades, which contribute to the progressive neurodegeneration seen in these diseases. In this study, we provide an overview of the genetic defects associated with lysosomal storage diseases and their impact on the induction of neuro-immune inflammation. By understanding the underlying mechanisms behind these diseases, we aim to provide new insights into potential biomarkers and therapeutic targets for monitoring and managing the severity of these diseases. In conclusion, lysosomal storage diseases present a complex challenge for patients and clinicians, but this study offers a comprehensive overview of the impact of these diseases on the central and peripheral nervous systems and provides a foundation for further research into potential treatments.

[Glial cells and pharmacological targets in Sandhoff disease]

Sandhoff disease (SD) is a genetic disorder caused by a mutation in the β-hexosaminidase B (HexB) gene in humans. This results in the massive accumulation of GM2 gangliosides in the nervous system, causing progressive neurodegeneration. The symptoms of SD include muscle weakness, seizures, and mental illness;along with loss of muscle coordination, vision, and hearing. In the most severe form, the onset begins during early infancy, and death usually occurs within 3-5 years of age. The established animal model, Hexb-deficient (Hexb^-/-) mouse, shows abnormalities that resemble the severe phenotype found in human infants. We have previously reported that activated microglia causes astrogliosis in Hexb^-/- mouse at the early stage of development that can be ameliorated via immunosuppression. Moreover, within the cerebral cortices of Hexb^-/- mouse, reactive astrocytes were found to express adenosine A_2A receptors in later inflammatory phases. Inhibiting this receptor with istradefylline decreases the number of activated microglial cells and inflammatory cytokines/chemokines. Thus, we underline the importance of the astrocytic A_2A receptor as a sensor, in regulating microglial activation in the late phase of inflammation.

The role of brain innate immune response in lysosomal storage disorders: fundamental process or evolutionary side effect?

Sphingolipidoses are diseases caused by mutations in genes responsible for sphingolipid degradation and thereby lead to sphingolipid accumulation. Most sphingolipidoses have a neurodegenerative manifestation characterized by innate immune activation in the brain. However, the role of the immune response in disease progression is ill-understood. In contrast to infectious diseases, immune activation is unable to eliminate the offending agent in sphingolipidoses resulting in ineffective, chronic inflammation. This paradox begs two fundamental questions: Why has this immune response evolved in sphingolipidoses? What role does it play in disease progression? Here, starting from the observation that sphingolipids (SLs) are elevated also in infectious diseases, I discuss the possibility that the activation of the brain immune response by SLs has evolved as a part of the immune response against pathogens and plays no major role in sphingolipidoses.

Glycosphingolipids and neuroinflammation in Parkinson's disease

Parkinson's disease is a progressive neurodegenerative disease characterized by the loss of dopaminergic neurons of the nigrostriatal pathway and the formation of neuronal inclusions known as Lewy bodies. Chronic neuroinflammation, another hallmark of the disease, is thought to play an important role in the neurodegenerative process. Glycosphingolipids are a well-defined subclass of lipids that regulate crucial aspects of the brain function and recently emerged as potent regulators of the inflammatory process. Deregulation in glycosphingolipid metabolism has been reported in Parkinson's disease. However, the interrelationship between glycosphingolipids and neuroinflammation in Parkinson's disease is not well known. This review provides a thorough overview of the links between glycosphingolipid metabolism and immune-mediated mechanisms involved in neuroinflammation in Parkinson's disease. After a brief presentation of the metabolism and function of glycosphingolipids in the brain, it summarizes the evidences supporting that glycosphingolipids (i.e. glucosylceramides or specific gangliosides) are deregulated in Parkinson's disease. Then, the implications of these deregulations for neuroinflammation, based on data from human inherited lysosomal glycosphingolipid storage disorders and gene-engineered animal studies are outlined. Finally, the key molecular mechanisms by which glycosphingolipids could control neuroinflammation in Parkinson's disease are highlighted. These include inflammasome activation and secretion of pro-inflammatory cytokines, altered calcium homeostasis, changes in the blood-brain barrier permeability, recruitment of peripheral immune cells or production of autoantibodies.

GM2 Gangliosidoses: Clinical Features, Pathophysiological Aspects, and Current Therapies

GM2 gangliosidoses are a group of pathologies characterized by GM2 ganglioside accumulation into the lysosome due to mutations on the genes encoding for the β-hexosaminidases subunits or the GM2 activator protein. Three GM2 gangliosidoses have been described: Tay-Sachs disease, Sandhoff disease, and the AB variant. Central nervous system dysfunction is the main characteristic of GM2 gangliosidoses patients that include neurodevelopment alterations, neuroinflammation, and neuronal apoptosis. Currently, there is not approved therapy for GM2 gangliosidoses, but different therapeutic strategies have been studied including hematopoietic stem cell transplantation, enzyme replacement therapy, substrate reduction therapy, pharmacological chaperones, and gene therapy. The blood-brain barrier represents a challenge for the development of therapeutic agents for these disorders. In this sense, alternative routes of administration (e.g., intrathecal or intracerebroventricular) have been evaluated, as well as the design of fusion peptides that allow the protein transport from the brain capillaries to the central nervous system. In this review, we outline the current knowledge about clinical and physiopathological findings of GM2 gangliosidoses, as well as the ongoing proposals to overcome some limitations of the traditional alternatives by using novel strategies such as molecular Trojan horses or advanced tools of genome editing.

Prevalence of antibodies to ganglioside and Hep 2 in Gaucher, Niemann - Pick type C and Sanfilippo diseases

Lysosomal Storage Diseases (LSDs) are rare genetic diseases, the majority of which are caused by specific lysosomal enzyme deficiencies and all are characterized by malfunctioning lysosomes. Lysosomes are key regulators of many different cellular processes and are vital for the function of the immune system. Several studies have shown the coexistence of LSDs and immune abnormalities. In this study, we investigated the presence of autoantibodies in the plasma of patients with Gaucher disease (GD; n = 6), Sanfilippo Syndrome B (SFB; n = 8) and Niemann - Pick type C disease (NPC; n = 5) before and following Miglustat treatment (n = 3). All were examined for antibodies to antigens of Hep-2 cells and antiganglioside antibodies (AGSA). No autoantibodies were detected in GD patients. 3/8 SFB patients showed only AGSA (2/3 IgM / IgG; 1/3 IgG), 3/8 only anti-Sm E/F and 2/8 showed both IgM / IgG or IgG AGSA and anti-Sm E/F. 3/5 NPC patients showed AGSA (2/3 IgM and IgG, 1/3 IgM) and one anti-Sm E/F and IgM AGSA. Following treatment one patient with no AGSA developed IgM AGSA and two with both IgG and IgM showed only IgG AGSA. In our study, investigating similar numbers of patients, autoantibodies were observed in NPC and SFB patients but not in GD patients. Our findings suggest that, independently of the development of an autoimmune disease in patients with LSDs, there seems to be an autoimmune activation that differs in different disorders. Further studies including more patients, also at different stages of disease and treatment, are needed in order to get further insight into the immune irregularities associated with different LSDs and their significance.

Abnormal organization during neurodevelopment in a mouse model of Sandhoff disease

Sandhoff disease (SD) is a genetic disorder caused by a mutation of HEXB, which is the β-subunit gene of β-hexosaminidase A and B (HexA and HexB) in humans. HEXB mutation reduces HexA and HexB enzymatic activities, and results in the massive accumulation of ganglioside GM2 in the nervous system. Severe phenotypes of SD show progressive neurodegeneration in human infants, and lysosomal dysfunction that may affect the early development of the nervous system. In a previous study, neural stem cells (NSCs) and induced pluripotent stem cells derived from SD model mice, which are Hexb-deficient (Hexb^-/-), demonstrated impaired neuronal differentiation. This study investigated early neurodevelopment in vivo using Hexb^-/- mice. The structure of adult cerebral cortices of Hexb^-/- mice was normal. However, the expression of Sox2, an NSC-related gene, was reduced in the embryonic cerebral cortices of Hexb^-/- mice. Moreover, a reduction of early neuronal migration and differentiation was observed in the embryonic cerebral cortices of Hexb^-/- mice. In addition, we showed that the production of layer-specific neurons was delayed in somatosensory cerebral cortices of Hexb^-/- mice. These findings suggest that the alterations observed in embryonic Hexb^-/- mice may contribute to deficits in neurodevelopment of SD.

Improvement in dysmyelination by the inhibition of microglial activation in a mouse model of Sandhoff disease

Sandhoff disease (SD) is a genetic disorder caused by a mutation of the β-subunit gene β-hexosaminidase B (HexB) in humans, which results in the massive accumulation of the ganglioside GM2 and related glycosphingolipids in the nervous system. SD causes progressive neurodegeneration and changes in white matter in human infants. An animal model of SD has been established, Hexb-deficient (Hexb) mice, which shows abnormalities resembling the severe phenotype found in human infants. Previously, we reported that the activation state of microglia caused astrogliosis in the early stage of Hexb mouse development. To study how the symptoms of SD develop, we explored the difference in gene expression between 4-week-old Hexb and Hexb mouse cerebral cortices by microarray analysis. The data indicated not only the upregulation of immune system-related genes but also the downregulation of myelin-related genes in the 4-week-old Hexb mouse cerebral cortices. To test the correlation between inflammation and dysmyelination, we generated double-knockout mice of Hexb and the Fc receptor γ gene (Fcrγ), which is a regulator of autoimmune responses. Dysmyelination recovered in these double-knockout mice. The number of oligodendrocyte progenitors, which expressed platelet-derived growth factor receptor-α, did not change in the 2-week-old mouse brain. These results indicate that microglial activation plays an important role in the myelination process, without influencing the number of oligodendrocyte progenitors, in the development of Hexb mice.

Lysosomal storage diseases

Lysosomal storage diseases (LSDs) are a group of over 70 diseases that are characterized by lysosomal dysfunction, most of which are inherited as autosomal recessive traits. These disorders are individually rare but collectively affect 1 in 5,000 live births. LSDs typically present in infancy and childhood, although adult-onset forms also occur. Most LSDs have a progressive neurodegenerative clinical course, although symptoms in other organ systems are frequent. LSD-associated genes encode different lysosomal proteins, including lysosomal enzymes and lysosomal membrane proteins. The lysosome is the key cellular hub for macromolecule catabolism, recycling and signalling, and defects that impair any of these functions cause the accumulation of undigested or partially digested macromolecules in lysosomes (that is, 'storage') or impair the transport of molecules, which can result in cellular damage. Consequently, the cellular pathogenesis of these diseases is complex and is currently incompletely understood. Several LSDs can be treated with approved, disease-specific therapies that are mostly based on enzyme replacement. However, small-molecule therapies, including substrate reduction and chaperone therapies, have also been developed and are approved for some LSDs, whereas gene therapy and genome editing are at advanced preclinical stages and, for a few disorders, have already progressed to the clinic.

Two-Year Follow-Up Magnetic Resonance Imaging and Spectroscopy Findings and Cerebrospinal Fluid Analysis of a Dog with Sandhoff's Disease

A 13‐month‐old female Toy Poodle was presented for progressive ataxia and intention tremors of head movement. The diagnosis of Sandhoff's disease (GM2 gangliosidosis) was confirmed by deficient β‐N‐acetylhexosaminidase A and B activity in circulating leukocytes and identification of the homozygous mutation (HEXB: c.283delG). White matter in the cerebrum and cerebellum was hyperintense on T2‐weighted and fluid‐attenuated inversion recovery magnetic resonance images. Over the next 2 years, the white matter lesions expanded, and bilateral lesions appeared in the cerebellum and thalamus, associated with clinical deterioration. Magnetic resonance spectroscopy showed progressive decrease in brain N‐acetylaspartate, and glycine‐myo‐inositol and lactate‐alanine were increased in the terminal clinical stage. The concentrations of myelin basic protein and neuron specific enolase in cerebrospinal fluid were persistently increased. Imaging and spectroscopic appearance correlated with histopathological findings of severe myelin loss in cerebral and cerebellar white matter and destruction of the majority of cerebral and cerebellar neurons.

Emptying the stores: lysosomal diseases and therapeutic strategies

Lysosomal storage disorders (LSDs) - designated as 'orphan' diseases - are inborn errors of metabolism caused by defects in genes that encode proteins involved in various aspects of lysosomal homeostasis. For many years, LSDs were viewed as unattractive targets for the development of therapies owing to their low prevalence. However, the development and success of the first commercial biologic therapy for an LSD - enzyme replacement therapy for type 1 Gaucher disease - coupled with regulatory incentives rapidly catalysed commercial interest in therapeutically targeting LSDs. Despite ongoing challenges, various therapeutic strategies for LSDs now exist, with many agents approved, undergoing clinical trials or in preclinical development.

Overview of immune abnormalities in lysosomal storage disorders

The critical relevance of the lysosomal compartment for normal cellular function can be proved by numbering the clinical phenotypes that arise in lysosomal storage disorders (LSDs), a group of around 70 different monogenic autosomal or X-linked syndromes, caused by specific lysosomal enzyme deficiencies: all LSDs are characterized by progressive accumulation of heterogeneous biologic materials in the lysosomes of various parts of the body such as viscera, skeleton, skin, heart, and central nervous system. At least a fraction of LSDs has been associated with mixed abnormalities involving the immune system, while some patients with LSDs may result more prone to autoimmune phenomena. A large production of proinflammatory cytokines has been observed in Gaucher and Fabry diseases, and wide different autoantibody production has been also reported in both. Many immune-mediated reactions are crucial to the pathogenesis of different inflammatory signs in mucopolysaccharidoses, and subverted heparan sulphate catabolism might dysregulate cellular homeostasis in the brain of these patients. Furthermore, an inappropriate activation of microglia is implicated in the neurodegenerative foci of Niemann-Pick disease, in which abnormal signalling pathways are activated by impaired sphingolipid metabolism. In addition, not the simple impaired catabolism of gangliosides per se, but also the production of anti-ganglioside autoantibodies contributes to the neurological disease of gangliosidoses. Even if the exact relationship between the modification of lysosomal activities and modulation of the immune system remains obscure, there is emerging evidence of different impaired immunity responses in a variety of LSDs: in this review we investigate and summarize the immune abnormalities and/or clinical data about immune system irregularities which have been described in a subset of LSDs.

Abnormal differentiation of Sandhoff disease model mouse-derived multipotent stem cells toward a neural lineage

In Sandhoff disease (SD), the activity of the lysosomal hydrolytic enzyme, β-hexosaminidase (Hex), is lost due to a Hexb gene defect, which results in the abnormal accumulation of the substrate, GM2 ganglioside (GM2), in neuronal cells, causing neuronal loss, microglial activation, and astrogliosis. We established induced pluripotent stem cells from the cells of SD mice (SD-iPSCs). In the present study, we investigated the occurrence of abnormal differentiation and development of a neural lineage in the asymptomatic phase of SD in vitro using SD mouse fetus-derived neural stem cells (NSCs) and SD-iPSCs. It was assumed that the number of SD mouse fetal brain-derived NSCs was reduced and differentiation was promoted, resulting in the inhibition of differentiation into neurons and enhancement of differentiation into astrocytes. The number of SD-iPSC-derived NSCs was also reduced, suggesting that the differentiation of NSCs was promoted, resulting in the inhibition of differentiation into neurons and enhancement of that into astrocytes. This abnormal differentiation of SD-iPSCs toward a neural lineage was reduced by the glucosylceramide synthase inhibitor, miglustat. Furthermore, abnormal differentiation toward a neural lineage was reduced in SD-iPSCs with Hexb gene transfection. Therefore, differentiation ability along the time axis appears to be altered in SD mice in which the differentiation ability of NSCs is promoted and differentiation into neurons is completed earlier, while the timing of differentiation into astrocytes is accelerated. These results clarified that the abnormal differentiation of SD-iPSCs toward a neural lineage in vitro was shown to reflect the pathology of SD.

Accumulated α-synuclein affects the progression of GM2 gangliosidoses

The accumulation of α-synuclein (ASyn) has been observed in several lysosomal storage diseases (LSDs) but it remains unclear if ASyn accumulation contributes to LSD pathology. ASyn also accumulates in the neurons of Sandhoff disease (SD) patients and SD model mice (Hexb-/- ASyn+/+ mice). SD is a lysosomal storage disorder caused by the absence of a functional β-subunit on the β-hexosaminidase A and B enzymes, which leads to the accumulation of ganglioside in the central nervous system. Here, we explored the role of accumulated ASyn in the progression of Hexb-/- mice by creating a Hexb-/- ASyn-/- double-knockout mice. Our results show that Hexb-/- ASyn-/- mice demonstrated active microglia levels and less dopaminergic neuron loss, without altering the neuronal storage of ganglioside. The autophagy and ubiquitin proteasome pathways are defective in the neurons of Hexb-/- ASyn+/+ mice. In ultrastructural physiological studies, the mitochondria structures look degenerated and dysfunctional. As a result, expression of manganese superoxide dismutase 2 are reduced, and reactive oxygen species-mediated oxidative damage in the neurons of Hexb-/- ASyn+/+ mice. Interestingly, these dysfunctions improved in Hexb-/- ASyn-/- mice. But any clinical improvement were hardly observed in Hexb-/- ASyn-/- mice. Taken together, these findings suggest that ASyn accumulation plays an important role in the pathogenesis of neuropathy in SD and other LSDs, and is therefore a target for novel therapies.

Pathogenic role of ganglioside metabolism in neurodegenerative diseases

Ganglioside metabolism is altered in several neurodegenerative diseases, and this may participate in several events related to the pathogenesis of these diseases. Most changes occur in specific areas of the brain and their distinct membrane microdomains or lipid rafts. Antiganglioside antibodies may be involved in dysfunction of the blood-brain barrier and disease progression in these diseases. In lipid rafts, interactions of glycosphingolipids, including ganglioside, with proteins may be responsible for the misfolding events that cause the fibril and/or aggregate processing of disease-specific proteins, such as α-synuclein, in Parkinson's disease, huntingtin protein in Huntington's disease, and copper-zinc superoxide dismutase in amyotrophic lateral sclerosis. Targeting ganglioside metabolism may represent an underexploited opportunity to design novel therapeutic strategies for neurodegeneration in these diseases.

[Molecular pathogenesis and therapeutic approach of GM2 gangliosidosis]

Tay-Sachs and Sandhoff diseases (GM2 gangliosidoses) are autosomal recessive lysosomal storage diseases caused by gene mutations in HEXA and HEXB, each encoding human lysosomal β-hexosaminidase α-subunits and β-subunits, respectively. In Tay-Sachs disease, excessive accumulation of GM2 ganglioside (GM2), mainly in the central nervous system, is caused by a deficiency of the HexA isozyme (αβ heterodimer), resulting in progressive neurologic disorders. In Sandhoff disease, combined deficiencies of HexA and HexB (ββ homodimer) cause not only the accumulation of GM2 but also of oligosaccharides carrying terminal N-acetylhexosamine residues (GlcNAc-oligosaccharides), resulting in systemic manifestations including hepatosplenomegaly as well as neurologic symptoms. Hence there is little clinically effective treatment for these GM2 gangliosidoses. Recent studies on the molecular pathogenesis in Sandhoff disease patients and disease model mice have shown the involvement of microglial activation and chemokine induction in neuroinflammation and neurodegeneration in this disease. Experimental and therapeutic approaches, including recombinant enzyme replacement, have been performed using Sandhoff disease model mice, suggesting the future application of novel techniques to treat GM2 gangliosidoses (Hex deficiencies), including Sandhoff disease as well as Tay-Sachs disease. In this study, we isolated astrocytes and microglia from the neonatal brain of Sandhoff disease model mice and demonstrated abnormalities of glial cells. Moreover, we demonstrated the therapeutic effect of an intracerebroventricular administration of novel recombinant human HexA carrying a high content of M6P residue in Sandhoff disease model mice.

Mucopolysaccharide diseases: a complex interplay between neuroinflammation, microglial activation and adaptive immunity

Mucopolysaccharide (MPS) diseases are lysosomal storage disorders (LSDs) caused by deficiencies in enzymes required for glycosaminoglycan (GAG) catabolism. Mucopolysaccharidosis I (MPS I), MPS IIIA, MPS IIIB and MPS VII are deficient in the enzymes α-L-Iduronidase, Heparan-N-Sulphatase, N-Acetylglucosaminidase and Beta-Glucuronidase, respectively. Enzyme deficiency leads to the progressive multi-systemic build-up of heparan sulphate (HS) and dermatan sulphate (DS) within cellular lysosomes, followed by cell, tissue and organ damage and in particular neurodegeneration. Clinical manifestations of MPS are well established; however as lysosomes represent vital components of immune cells, it follows that lysosomal accumulation of GAGs could affect diverse immune functions and therefore influence disease pathogenesis. Theoretically, MPS neurodegeneration and GAGs could be substantiating a threat of danger and damage to alert the immune system for cellular clearance, which due to the progressive nature of MPS storage would propagate disease pathogenesis. Innate immunity appears to have a key role in MPS; however the extent of adaptive immune involvement remains to be elucidated. The current literature suggests a complex interplay between neuroinflammation, microglial activation and adaptive immunity in MPS disease.

The cellular pathology of lysosomal diseases

With a constitutive recycling function and the capacity to digest exogenous material as well as endogenous organelles in the process of autophagy, lysosomes are at the heart of the living cell. Dynamic interactions with other cellular components ensure that the lysosomal compartment is a central point of convergence in countless diverse diseases. Inborn lysosomal (storage) diseases represent about 70 genetically distinct conditions, with a combined birth frequency of about 1 in 7500. Many are associated with macromolecular storage, causing physical disruption of the organelle and cognate structures; in neurons, ectopic dendritogenesis and axonal swelling due to distension with membraneous tubules and autophagic vacuoles are observed. Disordered autophagy is almost universal in lysosomal diseases but biochemical injury due to toxic metabolites such as lysosphingolipid molecules, abnormal calcium homeostasis and endoplasmic reticulum stress responses and immune-inflammatory processes occur. However, in no case have the mechanistic links between individual clinico-pathological manifestations and the underlying molecular defect been precisely defined. With access to the external fluid-phase and intracellular trafficking pathways, the lysosome and its diseases are a focus of pioneering investment in biotechnology; this has generated innovative orphan drugs and, in the case of Gaucher's disease, effective treatment for the haematological and visceral manifestations. Given that two-thirds of lysosomal diseases have potentially devastating consequences in the nervous system, future therapeutic research will require an integrative understanding of the unitary steps in their neuro pathogenesis. Informative genetic variants illustrated by patients with primary defects in this organelle offer unique insights into the central role of lysosomes in human health and disease. We provide a conspectus of inborn lysosomal diseases and their pathobiology; the cryptic evolution of events leading to irreversible changes may be dissociated from the cellular storage phenotype, as revealed by the outcome of therapeutic gene transfer undertaken at different stages of disease.

[Glycobiology and neurological disorders]

Many researchers now recognize the importance of glycobiological research achievements. Glycoside-containing substances such as proteins (glycoproteins) and lipids (glycosphingolipids) have been involved in many important and essential events for normal life. The production of glycoside residues of the proteins is only partially regulated by the genes. In this talk, I will make a brief description of what glycobiology can influence the future of neurological research arena and how glycoproteins and glycolipids affect the normal biology of the neurons. Furthermore, I will introduce you some evidences that many neurological disorders such as Alzheimer's disease and immune-mediated encephalitis have special relationships with glycobiological abnormalities. I also explain the structures and functions of lipid rafts, caveolae, and glycosynapse and their roles in the intracellular signal transduction and cell motility.

Thymic involution and corticosterone level in Sandhoff disease model mice: new aspects the pathogenesis of GM2 gangliosidosis

Sandhoff disease (SD) is a lysosomal disease caused by a mutation of the HEXB gene associated with excessive accumulation of GM2 ganglioside (GM2) in lysosomes and neurological manifestations. Production of autoantibodies against the accumulated gangliosides has been reported to be involved in the progressive pathogenesis of GM2 gangliosidosis, although the underlying mechanism has not been fully elucidated. The thymus is the key organ in the acquired immune system including the development of autoantibodies. We showed here that thymic involution and an increase in cell death in the organ occur in SD model mice at a late stage of the pathogenesis. Dramatic increases in the populations of Annexin-V(+) cells and terminal deoxynucletidyl transferase dUTP nick end labeling (TUNEL) (+) cells were observed throughout the thymuses of 15-week old SD mice. Enhanced caspase-3/7 activation, but not that of caspase-1/4, -6 ,-8, or -9, was also demonstrated. Furthermore, the serum level of corticosterone, a potent inducer of apoptosis of thymocytes, was elevated during the same period of apoptosis. Our studies suggested that an increase in endocrine corticosterone may be one of the causes that accelerate the apoptosis of thymocytes leading to thymic involution in GM2 gangliosidosis, and thus can be used as a disease marker for evaluation of the thymic condition and disease progression.

Treating inflammation in childhood neurodegenerative disorders

Inflammation of the central nervous system is a prominent feature in many childhood neurodegenerative conditions, with various studies demonstrating the upregulation of the innate and adaptive immune system. Recent evidence also suggests that this inflammatory process can contribute to further neurodegeneration. Furthermore, immunosuppression in mouse models of a few lysosomal storage disorders has demonstrated that attenuation of this immune response can influence the clinical and neuropathological progression. However, there are significant challenges before this finding translates to patient care. Treating inflammation in neurodegenerative conditions requires the identification of the time point when inflammation becomes pathogenic, after which the safest therapeutic strategies are required to target the various components and confounders of inflammation. Nevertheless, as the progress made towards effective gene-, cellular-, and enzyme-based therapy in most of these disorders has been disappointing, treating pathogenic inflammation may offer the clinician another therapeutic strategy in managing these devastating disorders.

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.

Common and uncommon pathogenic cascades in lysosomal storage diseases

Lysosomal storage diseases (LSDs), of which about 50 are known, are caused by the defective activity of lysosomal proteins, resulting in accumulation of unmetabolized substrates. As a result, a variety of pathogenic cascades are activated such as altered calcium homeostasis, oxidative stress, inflammation, altered lipid trafficking, autophagy, endoplasmic reticulum stress, and autoimmune responses. Some of these pathways are common to many LSDs, whereas others are only altered in a subset of LSDs. We now review how these cascades impact upon LSD pathology and suggest how intervention in the pathways may lead to novel therapeutic approaches.

Unilaterally and rapidly progressing white matter lesion and elevated cytokines in a patient with Tay-Sachs disease

We report the case of a girl with Tay-Sachs disease who had convulsions and deteriorated rapidly after an upper respiratory infection at the age of 11 months. At the age of 16 months, her seizures became intractable and magnetic resonance imaging of the brain showed high signal intensity on T2-weighted images and marked swelling in the white matter and basal nucelei of the right hemisphere. Her seizures and right hemisphere lesion improved with glycerol and dexamethasone treatment. When dexamethasone was discontinued, her symptoms worsened and lesions later appeared in the left hemisphere. Her cerebrospinal fluid showed elevated levels of the cytokines TNF-alpha and IL-5. It is considered that inflammation contributes to disease progression in Tay-Sachs disease.

Systems biology and its application to the understanding of neurological diseases

Recent advances in molecular biology, neurobiology, genetics, and imaging have demonstrated important insights about the nature of neurological diseases. However, a comprehensive understanding of their pathogenesis is still lacking. Although reductionism has been successful in enumerating and characterizing the components of most living organisms, it has failed to generate knowledge on how these components interact in complex arrangements to allow and sustain two of the most fundamental properties of the organism as a whole: its fitness, also termed its robustness, and its capacity to evolve. Systems biology complements the classic reductionist approaches in the biomedical sciences by enabling integration of available molecular, physiological, and clinical information in the context of a quantitative framework typically used by engineers. Systems biology employs tools developed in physics and mathematics such as nonlinear dynamics, control theory, and modeling of dynamic systems. The main goal of a systems approach to biology is to solve questions related to the complexity of living systems such as the brain, which cannot be reconciled solely with the currently available tools of molecular biology and genomics. As an example of the utility of this systems biological approach, network-based analyses of genes involved in hereditary ataxias have demonstrated a set of pathways related to RNA splicing, a novel pathogenic mechanism for these diseases. Network-based analysis is also challenging the current nosology of neurological diseases. This new knowledge will contribute to the development of patient-specific therapeutic approaches, bringing the paradigm of personalized medicine one step closer to reality.

Treating lysosomal storage disorders: current practice and future prospects

There are over 40 human disease states that are caused by defects in various aspects of lysosomal function. Over the past two decades there has been dramatic progress in the development and evaluation of therapies for lysosomal storage disorders, several of which are now in routine clinical use or in clinical trials. The greatest current challenge is in developing effective therapies for treating the CNS manifestations of these complex disorders. In this article, we will review the current therapies/approaches being considered for treating lysosomal storage diseases and give a perspective on the scientific, medical, social and ethical issues they raise.

Early deficits in motor coordination and cognitive dysfunction in a mouse model of the neurodegenerative lysosomal storage disorder, Sandhoff disease

Mouse models of lysosomal storage diseases, including Sandhoff disease, are frequently employed to test therapies directed at the central nervous system. We backbred such mice and conducted a behavioral test battery which included sensorimotor and cognitive assessments. This is the first report of short-term memory deficits in a murine model of Sandhoff disease. We also document early onset of motor deficits using the balance beam test.

Immune system irregularities in lysosomal storage disorders

Lysosomal storage disorders (LSDs) are genetically inherited diseases characterized by the accumulation of disease-specific biological materials such as proteolipids or metabolic intermediates within the lysosome. The lysosomal compartment's central importance to normal cellular function can be appreciated by examining the various pathologies that arise in LSDs. These disorders are invariably fatal, and many display profound neurological impairment that begins in childhood. However, recent studies have revealed that several LSDs also have irregularities in the function of the immune system. Gaucher disease, mucopolysaccharidosis VII, and alpha-mannosidosis are examples of a subset of LSD patients that are predisposed towards immune suppression. In contrast, GM2 gangliosidosis, globoid cell leukodystrophy, Niemann-Pick disease type C1 and juvenile neuronal ceroid lipofuscinosis are LSDs that are predisposed towards immune system hyperactivity. Antigen presentation and processing by dedicated antigen presenting cells (APCs), secretion of pore-forming perforins by cytotoxic-T lymphocytes, and release of pro-inflammatory mediators by mast cells are among the many crucial immune system functions in which the lysosome plays a central role. Although the relationship between the modification of the lysosomal compartment in LSDs and modulation of the immune system remains unknown, there is emerging evidence for early neuroimmune responses in a variety of LSDs. In this review we bridge biochemical studies on the lysosomal compartment's role in the immune system with clinical data on immune system irregularities in a subset of LSDs.

Pathology of mucopolysaccharidosis IIIA in Huntaway dogs

Dogs with mucopolysaccharidosis (MPS) IIIA were bred within an experimental colony. As part of characterizing them as a model for testing therapeutic strategies for the analogous disease of children, a pathologic study was undertaken. By histology, there were variably stained storage cytosomes within neurons, including many that stained for gangliosides. On ultrastructure examination, these cytosomes contained either moderately dense granular material, tentatively interpreted as precipitated glycosaminoglycan; a variety of multilaminar bodies, interpreted as being associated with secondary accumulation of gangliosides; or a mixture of both types. In the liver, storage vesicles also contained excess glycogen as a secondary storage product. In various tissues, there were large foamy macrophages. In the brain, many of these were in juxtaposition with neurons, and, on ultrastructure examination, they contained storage cytosomes similar to those in neurons. However, the neuron in association with such a macrophage frequently showed little such material.

Neuronal and glial accumulation of alpha- and beta-synucleins in human lipidoses

A number of the lysosomal storage diseases that have now been characterized are associated with intra-lysosomal accumulation of lipids, caused by defective lysosomal enzymes. We have previously reported neuronal accumulation of both alpha- and beta-synucleins in brain tissue of a GM2 gangliosidosis mouse model. Although alpha-synuclein has been implicated in several neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy, its functions remain largely unclear. In our present study, we have examined a cohort of human lipidosis cases, including Sandhoff disease, Tay-Sachs disease, metachromatic leukodystrophy, beta-galactosialidosis and adrenoleukodystrophy, for the expression of alpha- and beta-synucleins and the associated lipid storage levels. The accumulation of alpha-synuclein was found in brain tissue in not only cases of lysosomal storage diseases, but also in instances of adrenoleukodystrophy, which is a peroxisomal disease. alpha-synuclein was detected in both neurons and glial cells of patients with these two disorders, although its distribution was found to be disease-dependent. In addition, alpha-synuclein-positive neurons were also found to be NeuN-positive, whereas NeuN-negative neurons did not show any accumulation of this protein. By comparison, the accumulation of beta-synuclein was detectable only in the pons of Sandhoff disease cases. This differential accumulation of alpha- and beta-synucleins in human lipidoses may be related to functional differences between these two proteins. In addition, the accumulation of alpha-synuclein may also be a condition that is common to lysosomal storage diseases and adrenoleukodystrophies that show an enhanced expression of this protein upon the elevation of stored lipids.

High incidence of autoantibodies in Fabry disease patients

Fabry disease (FD) is an X-linked disorder of glycosphingolipid catabolism that results from a deficiency of the lysosomal enzyme alpha-galactosidase A. This defect leads to the accumulation of its substrates, mainly globotriaosylceramide, in lysosomes of cells of different tissues. Different studies have shown the involvement of immunopathologies in different sphingolipidoses. The coexistence of FD and immune disorders such as systemic lupus erythematosus, rheumatoid arthritis and IgA nephropathy, has been described in the literature. The aim of this study was to evaluate the prevalence of a group of autoantibodies in a series of Argentine FD patients. Autoantibodies against extractable nuclear antigens (ENAs), double-stranded DNA, anticardiolipin and phosphatidylserine were assayed by ELISA. Lupus anticoagulants were also tested. Fifty-seven per cent of the samples showed reactivity with at least one autoantigen. Such reactivities were more frequent among males than among females. Antiphospholipid autoantibodies were detected in 45% of our patients. The high rate of thrombosis associated with FD could be related, at least in part, to the presence of antiphospholipid autoantibodies in Fabry patients. We found the presence of ENAs, which are a characteristic finding of rheumatological diseases, previous a frequent misdiagnosis of FD, in around 39% of the cases. The detection of a high level of autoantibodies must be correlated clinically to determine the existence of an underlying autoimmune disease. With the recent development of therapy, the life expectancy in FD will increase and autoimmune diseases might play an important role in the morbidity of FD.

Leukocyte and complement activation by GM1-specific antibodies is associated with acute motor axonal neuropathy in rabbits

Acute motor axonal neuropathy (AMAN) in humans is associated with the presence of GM1-specific antibodies. Immunization of rabbits with GM1-containing ganglioside mixtures, purified GM1, or Campylobacter jejuni lipo-oligosaccharide exhibiting a GM1-like structure elicits GM1-specific antibodies, but axonal polyneuropathy only occurs in a subset of animals. This study aimed to dissect the molecular basis for the variable induction of AMAN in rabbits. Therefore, we analyzed the pro-inflammatory characteristics of GM1-specific antibodies in plasma samples from ganglioside-immunized rabbits with and without neurological deficits. GM1-specific plasma samples from all rabbits with AMAN were capable of activating both complement and leukocytes, in contrast to none of the plasma samples from rabbits without paralysis. Furthermore, GM1-specific IgG-mediated activation of leukocytes was detected before the onset of clinical signs. These data suggest that AMAN only occurs in rabbits that develop GM1-specific antibodies with pro-inflammatory properties.

Cerebrospinal fluid biomarkers showing neurodegeneration in dogs with GM1 gangliosidosis: possible use for assessment of a therapeutic regimen

The present study investigated cerebrospinal fluid (CSF) biomarkers for estimating degeneration of the central nervous system (CNS) in experimental dogs with GM1 gangliosidosis and preliminarily evaluated the efficacy of long-term glucocorticoid therapy for GM1 gangliosidosis using the biomarkers identified here. GM1 gangliosidosis, a lysosomal storage disease that affects the brain and multiple systemic organs, is due to an autosomal recessively inherited deficiency of acid beta-galactosidase activity. Pathogenesis of GM1 gangliosidosis may include neuronal apoptosis and abnormal axoplasmic transport and inflammatory response, which are perhaps consequent to massive neuronal storage of GM1 ganglioside. In the present study, we assessed some possible CSF biomarkers, such as GM1 ganglioside, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), neuron-specific enolase (NSE) and myelin basic protein (MBP). Periodic studies demonstrated that GM1 ganglioside concentration, activities of AST and LDH, and concentrations of NSE and MBP in CSF were significantly higher in dogs with GM1 gangliosidosis than those in control dogs, and their changes were well related with the months of age and clinical course. In conclusion, GM1 ganglioside, AST, LDH, NSE and MBP could be utilized as CSF biomarkers showing CNS degeneration in dogs with GM1 gangliosidosis to evaluate the efficacy of novel therapies proposed for this disease. In addition, we preliminarily treated an affected dog with long-term oral administration of prednisolone and evaluated the efficacy of this therapeutic trial using CSF biomarkers determined in the present study. However, this treatment did not change either the clinical course or the CSF biomarkers of the affected dog, suggesting that glucocorticoid therapy would not be effective for treating GM1 gangliosidosis.

Distinct patterns of serum immunoreactivity as evidence for multiple brain-directed autoantibodies in juvenile neuronal ceroid lipofuscinosis

Autoantibodies to glutamic acid decarboxylase (GAD65) have been reported in sera from the Cln3(-/-) mouse model of juvenile neuronal ceroid lipofuscinosis (JNCL), and in individuals with this fatal paediatric neurodegenerative disorder. To investigate the existence of other circulating autoreactive antibodies, we used sera from patients with JNCL and other forms of neuronal ceroid lipofuscinosis (NCL) as primary antisera to stain rat and human central nervous system sections. JNCL sera displayed characteristic patterns of IgG, but not IgA, IgE or IgM immunoreactivity that was distinct from the other forms of NCL. Immunoreactivity of JNCL sera was not confined to GAD65-positive (GABAergic) neurons, but also stained multiple other cell populations. Preadsorption of JNCL sera with recombinant GAD65 reduced the intensity of the immunoreactivity, but did not significantly change its staining pattern. Moreover, sera from Stiff Person Syndrome and Type I Diabetes, disorders in which GAD65 autoantibodies are present, stained with profiles that were markedly different from JNCL sera. Collectively, these studies provide evidence of the presence of autoreactive antibodies within multiple forms of NCL, and are not exclusively directed towards GAD65.

IgG entry and deposition are components of the neuroimmune response in Batten disease

Patients and a mouse model of Batten disease, the juvenile form of neuronal ceroid lipofuscinosis (JNCL), raise autoantibodies against GAD65 and other brain-directed antigens. Here we investigate the adaptive component of the neuroimmune response. Cln3(-/-) mice have autoantibodies to GAD65 in their cerebrospinal fluid and elevated levels of brain bound immunoglobulin G (IgG). IgG deposition was found within human JNCL autopsy material, a feature that became more evident with increased age in Cln3(-/-) mice. The lymphocyte infiltration present in human and murine JNCL occurred late in disease progression, and was not capable of central/intrathecal IgG production. In contrast, we found evidence for an early systemic immune dysregulation in Cln3(-/-) mice. In addition evidence for a size-selective breach in the blood-brain barrier integrity in these mice suggests that systemically produced autoantibodies can access the JNCL central nervous system and contribute to a progressive inflammatory response.

Detection of new anti-neutral glycosphingolipids antibodies and their effects on Trk neurotrophin receptors

We screened sera from patients with various neurological disorders for the presence of anti-neutral glycosphingolipids antibodies and only found them in sera from relapsing polychondritis with limbic encephalitis patients. Neutral glycosphingolipids are resident in membrane lipid rafts where high affinity nerve growth factor (NGF) receptor, Trk is co-localized. Therefore, we examined whether these antibodies influence the action of NGF in NGF-responsive cells. The results strongly suggest that these antibodies enhance NGF-induced Trk autophosphorylation and neurite outgrowth as well as neurofilament M expression. These data strongly indicate that these anti-neutral glycosphingolipids antibodies have a functional impact on NGF-Trk-mediated intracellular signal transduction pathway.

Effective gene therapy in an authentic model of Tay-Sachs-related diseases

Tay-Sachs disease is a prototypic neurodegenerative disease. Lysosomal storage of GM2 ganglioside in Tay-Sachs and the related disorder, Sandhoff disease, is caused by deficiency of beta-hexosaminidase A, a heterodimeric protein. Tay-Sachs-related diseases (GM2 gangliosidoses) are incurable, but gene therapy has the potential for widespread correction of the underlying lysosomal defect by means of the secretion-recapture cellular pathway for enzymatic complementation. Sandhoff mice, lacking the beta-subunit of hexosaminidase, manifest many signs of classical human Tay-Sachs disease and, with an acute course, die before 20 weeks of age. We treated Sandhoff mice by stereotaxic intracranial inoculation of recombinant adeno-associated viral vectors encoding the complementing human beta-hexosaminidase alpha and beta subunit genes and elements, including an HIV tat sequence, to enhance protein expression and distribution. Animals survived for >1 year with sustained, widespread, and abundant enzyme delivery in the nervous system. Onset of the disease was delayed with preservation of motor function; inflammation and GM2 ganglioside storage in the brain and spinal cord was reduced. Gene delivery of beta-hexosaminidase A by using adeno-associated viral vectors has realistic potential for treating the human Tay-Sachs-related diseases.

The human obesity gene map: the 2005 update

This paper presents the 12th update of the human obesity gene map, which incorporates published results up to the end of October 2005. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTL) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2005, 176 human obesity cases due to single-gene mutations in 11 different genes have been reported, 50 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 244 genes that, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 408. The number of human obesity QTLs derived from genome scans continues to grow, and we now have 253 QTLs for obesity-related phenotypes from 61 genome-wide scans. A total of 52 genomic regions harbor QTLs supported by two or more studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably, with 426 findings of positive associations with 127 candidate genes. A promising observation is that 22 genes are each supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. The electronic version of the map with links to useful publications and relevant sites can be found at http://obesitygene.pbrc.edu.

Pathogenic autoantibodies: emerging insights into tissue injury

Accumulating evidence is emerging that B lymphocytes and autoantibodies are critical in the development of autoimmune disease. Even in certain disorders initially thought to be T cell-mediated, these immune components are now considered key players in the disease pathogenesis, and new autoantibody specificities have been added to the growing list of targets including cell surface receptors and ion channels that may be involved in a variety of neuropsychiatric and cardiovascular disorders. Studies of autoantibodies penetrating living cells suggest a dosage effect in generating a biological outcome in vivo. Some autoantibodies, such as those directed to double-stranded DNA, can bind to a variety of surrogate antigens located in different cellular compartments, and this may have different biological consequences. This polyreactive behavior could be related to their conformational diversity, or to the fact that the epitope recognized is distributed among other macromolecular antigens. In addition, recent studies revealed unsuspected mechanisms of pathogenesis, wherein autoantibodies have been described that can activate neuronal, endothelial cells or B lymphocytes. Other autoantibodies inactivate the target antigens, or exhibit a catalytic activity, releasing toxic oxygen products that may be linked to arthritic or atherosclerotic injury.

Fc receptors and their role in immune regulation and autoimmunity

The activation threshold of cells in the immune system is often tuned by cell surface molecules. The Fc receptors expressed on various hematopoietic cells constitute critical elements for activating or downmodulating immune responses and combines humoral and cell-mediated immunity. Thus, Fc receptors are the intelligent sensors of the immune status in the individual. However, impaired regulation by Fc receptors will lead to unresponsiveness or hyperreactivity to foreign as well as self-antigens. Murine models for autoimmune disease indicate the indispensable roles of the inhibitory Fc receptor in the suppression of such disorders, whereas activating-type FcRs are crucial for the onset and exacerbation of the disease. The development of many autoimmune diseases in humans may be caused by impairment of the human Fc receptor regulatory system. This review is aimed at providing a current overview of the mechanism of Fc receptor-based immune regulation and the possible scenario of how autoimmune disease might result from their dysfunction.

Storage solutions: treating lysosomal disorders of the brain

Many neurodegenerative diseases are characterized by the accumulation of undegradable molecules in cells or at extracellular sites in the brain. One such family of diseases is the lysosomal storage disorders, which result from defects in various aspects of lysosomal function. Until recently, there was little prospect of treating storage diseases involving the CNS. However, recent progress has been made in understanding these conditions and in translating the findings into experimental therapies. We review the developments in this field and discuss the similarities in pathological features between these diseases and some more common neurodegenerative disorders.

Specific induction of macrophage inflammatory protein 1-alpha in glial cells of Sandhoff disease model mice associated with accumulation of N-acetylhexosaminyl glycoconjugates

Sandhoff disease is a lysosomal storage disease caused by simultaneous deficiencies of beta-hexosaminidase A (HexA; alphabeta) and B (HexB; betabeta), due to a primary defect of the beta-subunit gene (HEXB) associated with excessive accumulation of GM2 ganglioside (GM2) and oligosaccharides with N-acetylhexosamine residues at their non-reducing termini, and with neurosomatic manifestations. To elucidate the neuroinflammatory mechanisms involved in its pathogenesis, we analyzed the expression of chemokines in Sandhoff disease model mice (SD mice) produced by disruption of the murine Hex beta-subunit gene allele (Hexb-/-). We demonstrated that chemokine macrophage inflammatory protein-1 alpha (MIP-1alpha) was induced in brain regions, including the cerebral cortex, brain stem and cerebellum, of SD mice from an early stage of the pathogenesis but not in other systemic organs. On the other hand, little changes in other chemokine mRNAs, including those of RANTES (regulated upon activation, normal T expressed and secreted), MCP-1 (monocyte chemotactic protein-1), SLC (secondary lymphoid-tissue chemokine), fractalkine and SDF-1 (stromal derived factor-1), were detected. Significant up-regulation of MIP-1alpha mRNA and protein in the above-mentioned brain regions was observed in parallel with the accumulation of natural substrates of HexA and HexB. Immunohistochemical analysis revealed that MIP-1alpha-immunoreactivity (IR) in the above-mentioned brain regions of SD mice was co-localized in Iba1-IR-positive microglial cells and partly in glial fibrillary acidic protein (GFAP)-IR-positive astrocytes, in which marked accumulation of N-acetylglucosaminyl (GlcNAc)-oligosaccharides was observed from the presymptomatic stage of the disease. In contrast, little MIP-1alpha-IR was observed in neurons in which GM2 accumulated predominantly. These results suggest that specific induction of MIP-1alpha might coincide with the accumulation of GlcNAc-oligosaccharides due to a HexB deficiency in resident microglia and astrocytes in the brains of SD mice causing their activation and acceleration of the progressive neurodegeneration in SD mice.

NSAIDs increase survival in the Sandhoff disease mouse: Synergy withN-butyldeoxynojirimycin

The GM2 gangliosidoses are caused by incomplete catabolism of GM2 ganglioside in the lysosome, leading to progressive storage and a neurodegenerative clinical course. An inflammatory response (microglial activation, macrophage infiltration, oxidative damage) has been found to be a consequence of GM2 storage in the brain, although it remains unclear whether this contributes to pathogenesis or disease progression. In this study, we treated Sandhoff disease mice with nonsteroidal antiinflammatory drugs (indomethacin, aspirin, and ibuprofen) and antioxidants (L-ascorbic acid and alpha-tocopherol acetate). The treated mice lived significantly longer than untreated littermates (12-23%, p <0.0001) and showed a slower rate of disease progression (p <0.001). When aspirin treatment was combined with substrate reduction therapy, synergy resulted (11%, p <0.05) with a maximum improvement of 73% in survival (p <0.00001). This study demonstrates that inflammation contributes to disease progression and identifies antiinflammatory and antioxidant therapies as a potential adjunctive approach to slow the clinical course of this and related disorders.