Subtypes Of Neuronal Ceroid Lipofuscinoses Research Articles

Enzyme Replacement Therapy for CLN2 Disease: MRI Volumetry Shows Significantly Slower Volume Loss Compared with a Natural History Cohort.

Neuronal ceroid lipofuscinoses are a group of neurodegenerative disorders. Recently, enzyme replacement therapy (ERT) was approved for neuronal ceroid lipofuscinosis type 2 (CLN2), a subtype of neuronal ceroid lipofuscinoses. The aim of this study was to quantify brain volume loss in CLN2 disease in patients on ERT in comparison with a natural history cohort using MRI. Nineteen (14 female, 5 male) patients with CLN2 disease at 1 UK center were studied using serial 3D T1-weighted MRI (follow-up time, 1-9 years). Brain segmentation was performed using FreeSurfer. Volume measurements for supratentorial gray and white matter, deep gray matter (basal ganglia/thalami), the lateral ventricles, and cerebellar gray and white matter were recorded. The volume change with time was analyzed using a linear mixed-effects model excluding scans before treatment onset. Comparison was made with a published natural history cohort of 12 patients (8 female, 4 male), which was re-analyzed using the same method. Brain volume loss of all segmented brain regions was much slower in treated patients compared with the natural history cohort. For example, supratentorial gray matter volume in treated patients decreased by a mean of 3% (SD, 0.74%) (P < .001) annually compared with an annual volume loss of a mean of 16.8% (SD, 1.5%) (P < .001) in the natural history cohort. Our treatment cohort showed a significantly slower rate of brain parenchymal volume loss compared with a natural history cohort in several anatomic regions. Our results complement prior clinical data that found a positive response to ERT. We demonstrate that automated MRI volumetry is a sensitive tool to monitor treatment response in children with CLN2 disease.

CNS-associated T-lymphocytes in a mouse model of Hereditary Spastic Paraplegia type 11 (SPG11) are therapeutic targets for established immunomodulators

Pharmacological targeting of neuroinflammation in distinct models of genetically mediated disorders of the central nervous system (CNS) has been shown to attenuate disease outcome significantly. These include mouse models mimicking distinct subtypes of neuronal ceroid lipofuscinoses (NCL, CLN diseases) as well as hereditary spastic paraplegia type 2 (HSP/SPG2). We here show in a model of another, complicated HSP form (SPG11) that there is neuroinflammation in distinct compartments of the diseased CNS. Using a proof-of-principle experiment, we provide evidence that genetically targeting the adaptive immune system dampens disease progression including gait disturbance, demonstrating a pathogenic impact of neuroinflammation. Translating these studies into a clinically applicable approach, we show that the established immunomodulators fingolimod and teriflunomide significantly attenuate the neurodegenerative phenotype and improve gait performance in the SPG11 model, even when applied relatively late during disease progression. Particularly abnormalities in gait coordination, representing ataxia, could be attenuated, while features indicative of reduced strength during walking did not respond to treatment. Our study identifies neuroinflammation by the adaptive immune system as a robust and targetable disease amplifier in a mouse model of SPG11 and may thus pave the way for a translational approach in humans implicating approved immunomodulators.

Glial Dysfunction and Its Contribution to the Pathogenesis of the Neuronal Ceroid Lipofuscinoses.

While significant efforts have been made in developing pre-clinical treatments for the neuronal ceroid lipofuscinoses (NCLs), many challenges still remain to bring children with NCLs a cure. Devising effective therapeutic strategies for the NCLs will require a better understanding of pathophysiology, but little is known about the mechanisms by which loss of lysosomal proteins causes such devastating neurodegeneration. Research into glial cells including astrocytes, microglia, and oligodendrocytes have revealed many of their critical functions in brain homeostasis and potential contributions to neurodegenerative diseases. Genetically modified mouse models have served as a useful platform to define the disease progression in the central nervous system across NCL subtypes, revealing a wide range of glial responses to disease. The emerging evidence of glial dysfunction questions the traditional “neuron-centric” view of NCLs, and would suggest that directly targeting glia in addition to neurons could lead to better therapeutic outcomes. This review summarizes the most up-to-date understanding of glial pathologies and their contribution to the pathogenesis of NCLs, and highlights some of the associated challenges that require further research.

Neurophysiological Findings in Neuronal Ceroid Lipofuscinoses.

Neuronal ceroid lipofuscinoses (NCLs) are a heterogeneous group of neurodegenerative diseases, characterized by progressive cerebral atrophy due to lysosomal storage disorder. Common clinical features include epileptic seizures, progressive cognitive and motor decline, and visual failure, which occur over different time courses according to subtypes. During the latest years, many advances have been done in the field of targeted treatments, and in the next future, gene therapies and enzyme replacement treatments may be available for several NCL variants. Considering that there is rapid disease progression in NCLs, an early diagnosis is crucial, and neurophysiological features might have a key role for this purpose. Across the different subtypes of NCLs, electroencephalogram (EEG) is characterized by a progressive deterioration of cerebral activity with slowing of background activity and disappearance of spindles during sleep. Some types of heterogeneous abnormalities, diffuse or focal, prevalent over temporal and occipital regions, are described in many NCL variants. Photoparoxysmal response to low-frequency intermittent photic stimulation (IPS) is a typical EEG finding, mostly described in CLN2, CLN5, and CLN6 diseases. Visual evoked potentials (VEPs) allow to monitor the visual functions, and the lack of response at electroretinogram (ERG) reflects retinal neurodegeneration. Taken together, EEG, VEPs, and ERG may represent essential tools toward an early diagnosis of NCLs.

Autophagy in the Neuronal Ceroid Lipofuscinoses (Batten Disease).

The neuronal ceroid lipofuscinoses (NCLs), also referred to as Batten disease, are a family of neurodegenerative diseases that affect all age groups and ethnicities around the globe. At least a dozen NCL subtypes have been identified that are each linked to a mutation in a distinct ceroid lipofuscinosis neuronal (CLN) gene. Mutations in CLN genes cause the accumulation of autofluorescent lipoprotein aggregates, called ceroid lipofuscin, in neurons and other cell types outside the central nervous system. The mechanisms regulating the accumulation of this material are not entirely known. The CLN genes encode cytosolic, lysosomal, and integral membrane proteins that are associated with a variety of cellular processes, and accumulated evidence suggests they participate in shared or convergent biological pathways. Research across a variety of non-mammalian and mammalian model systems clearly supports an effect of CLN gene mutations on autophagy, suggesting that autophagy plays an essential role in the development and progression of the NCLs. In this review, we summarize research linking the autophagy pathway to the NCLs to guide future work that further elucidates the contribution of altered autophagy to NCL pathology.

Altered protein secretion in Batten disease.

ABSTRACTThe neuronal ceroid lipofuscinoses (NCLs), collectively known as Batten disease, are a group of neurological diseases that affect all ages and ethnicities worldwide. There are 13 different subtypes of NCL, each caused by a mutation in a distinct gene. The NCLs are characterized by the accumulation of undigestible lipids and proteins in various cell types. This leads to progressive neurodegeneration and clinical symptoms including vision loss, progressive motor and cognitive decline, seizures, and premature death. These diseases have commonly been characterized by lysosomal defects leading to the accumulation of undigestible material but further research on the NCLs suggests that altered protein secretion may also play an important role. This has been strengthened by recent work in biomedical model organisms, including Dictyostelium discoideum, mice, and sheep. Research in D. discoideum has reported the extracellular localization of some NCL-related proteins and the effects of NCL-related gene loss on protein secretion during unicellular growth and multicellular development. Aberrant protein secretion has also been observed in mammalian models of NCL, which has allowed examination of patient-derived cerebrospinal fluid and urine for potential diagnostic and prognostic biomarkers. Accumulated evidence links seven of the 13 known NCL-related genes to protein secretion, suggesting that altered secretion is a common hallmark of multiple NCL subtypes. This Review highlights the impact of altered protein secretion in the NCLs, identifies potential biomarkers of interest and suggests that future work in this area can provide new therapeutic insight.

Paediatric-onset neuronal ceroid lipofuscinosis: first symptoms and presentation at diagnosis.

Neuronal ceroid lipofuscinoses (NCLs) are rare, progressive disorders. Through this series of 20 patients with NCL, we illustrate differences between subtypes in their presenting symptoms and clinical, imaging, and electrophysiological results to raise awareness of symptom diversity. Data were available on presenting symptoms, genetics, magnetic resonance imaging (MRI), electroencephalography (including with low-frequency intermittent photic stimulation), visual responses, and electron microscopy. Causal mutations were identified in 10 patients. Eleven patients had neuronal ceroid lipofuscinosis type 2 (CLN2) disease and their most common presenting symptom was seizures, although motor and language defects were also reported. Five patients with CLN2 disease showed abnormalities at initial MRI, but only three showed a photic response with low-frequency stimulation. Seizures were not as common a presenting symptom in other NCL subtypes. Patients with NCLs present with diverse symptoms, which may not be characteristic in early disease stages. These signs and symptoms should lead to rapid diagnostic confirmatory testing for NCLs. WHAT THIS PAPER ADDS: Disease presentation is not uniform for neuronal ceroid lipofuscinoses. Characteristic clinical test results may not be identified in early disease stages.

Autophagy\u2013lysosome pathway alterations and alpha-synuclein up-regulation in the subtype of neuronal ceroid lipofuscinosis, CLN5 disease

Neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative lysosomal storage disorders. CLN5 deficiency causes a subtype of NCL, referred to as CLN5 disease. CLN5 is a soluble lysosomal protein with an unclear function in the cell. Increased levels of the autophagy marker protein LC3-II have been reported in several subtypes of NCLs. In this report, we examine whether autophagy is altered in CLN5 disease. We found that the basal level of LC3-II was elevated in both CLN5 disease patient fibroblasts and CLN5-deficient HeLa cells. Further analysis using tandem fluorescent mRFP-GFP-LC3 showed the autophagy flux was increased. We found the alpha-synuclein (α-syn) gene SNCA was highly up-regulated in CLN5 disease patient fibroblasts. The aggregated form of α-syn is well known for its role in the pathogenicity of Parkinson’s disease. Higher α-syn protein levels confirmed the SNCA up-regulation in both patient cells and CLN5 knockdown HeLa cells. Furthermore, α-syn was localized to the vicinity of lysosomes in CLN5 deficient cells, indicating it may have a lysosome-related function. Intriguingly, knocking down SNCA reversed lysosomal perinuclear clustering caused by CLN5 deficiency. These results suggest α-syn may affect lysosomal clustering in non-neuronal cells, similar to its role in presynaptic vesicles in neurons.

Neuronal ceroid lipofuscinosis related ER membrane protein CLN8 regulates PP2A activity and ceramide levels

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative lysosomal storage disorders. CLN8 deficiency causes a subtype of NCL, referred to as CLN8 disease. CLN8 is an ER resident protein with unknown function; however, a role in ceramide metabolism has been suggested. In this report, we identified PP2A and its biological inhibitor I2PP2A as interacting proteins of CLN8. PP2A is one of the major serine/threonine phosphatases in cells and governs a wide range of signaling pathways by dephosphorylating critical signaling molecules. We showed that the phosphorylation levels of several substrates of PP2A, namely Akt, S6 kinase, and GSK3β, were decreased in CLN8 disease patient fibroblasts. This reduction can be reversed by inhibiting PP2A phosphatase activity with cantharidin, suggesting a higher PP2A activity in CLN8-deficient cells. Since ceramides are known to bind and influence the activity of PP2A and I2PP2A, we further examined whether ceramide levels in the CLN8-deficient cells were changed. Interestingly, the ceramide levels were reduced by 60% in CLN8 disease patient cells compared to controls. Furthermore, we observed that the conversion of ER-localized NBD-C6-ceramide to glucosylceramide and sphingomyelin in the Golgi apparatus was not affected in CLN8-deficient cells, indicating transport of ceramides from ER to the Golgi apparatus was normal. A model of how CLN8 along with ceramides affects I2PP2A and PP2A binding and activities is proposed.

Central nervous system stem cell transplantation for children with neuronal ceroid lipofuscinosis

Infantile and late-infantile neuronal ceroid lipofuscinoses (NCLs) are invariably fatal lysosomal storage diseases associated with defects in lysosomal enzyme palmitoyl-protein thioesterase 1 (PPT-1) or tripeptidyl peptidase 1 (TPP1) activity. Previous preclinical studies have demonstrated that human CNS stem cells (HuCNS-SCs) produce both PPT-1 and TPP1 and result in donor cell engraftment and reduced accumulation of storage material in the brain when tested in an NCL mouse model. HuCNS-SC transplantation was tested in an open-label dose-escalation Phase I clinical trial as a potential treatment for infantile and late-infantile NCL. Study design included direct neurosurgical transplantation of allogeneic HuCNS-SCs into the cerebral hemispheres and lateral ventricles accompanied by 12 months of immunosuppression. Six children with either the infantile or late-infantile forms of NCL underwent low- (3 patients) and high- (3 patients) dose transplantation of HuCNS-SCs followed by immunosuppression. The surgery, immunosuppression, and cell transplantation were well tolerated. Adverse events following transplantation were consistent with the underlying disease, and none were directly attributed to the donor cells. Observations regarding efficacy of the intervention were limited by the enrollment criteria requiring that patients be in advanced stages of disease. This study represents the first-in-human clinical trial involving transplantation of a purified population of human neural stem cells for a neurodegenerative disorder. The feasibility of this approach and absence of transplantation-related serious adverse events support further exploration of HuCNS-SC transplantation as a potential treatment for select subtypes of NCL, and possibly for other neurodegenerative disorders.

A metabolomic comparison of mouse models of the Neuronal Ceroid Lipofuscinoses

The Neuronal Ceroid Lipofuscinoses (NCL) are a group of fatal inherited neurodegenerative diseases in humans distinguished by a common clinical pathology, characterized by the accumulation of storage body material in cells and gross brain atrophy. In this study, metabolic changes in three NCL mouse models were examined looking for pathways correlated with neurodegeneration. Two mouse models; motor neuron degeneration (mnd) mouse and a variant model of late infantile NCL, termed the neuronal ceroid lipofuscinosis (nclf) mouse were investigated experimentally. Both models exhibit a characteristic accumulation of autofluorescent lipopigment in neuronal and non neuronal cells. The NMR profiles derived from extracts of the cortex and cerebellum from mnd and nclf mice were distinguished according to disease/wildtype status. In particular, a perturbation in glutamine and glutamate metabolism, and a decrease in γ-amino butyric acid (GABA) in the cerebellum and cortices of mnd (adolescent mice) and nclf mice relative to wildtype at all ages were detected. Our results were compared to the Cln3 mouse model of NCL. The metabolism of mnd mice resembled older (6month) Cln3 mice, where the disease is relatively advanced, while the metabolism of nclf mice was more akin to younger (1-2months) Cln3 mice, where the disease is in its early stages of progression. Overall, our results allowed the identification of metabolic traits common to all NCL subtypes for the three animal models.

A two-dimensional protein fragmentation-proteomic study of neuronal ceroid lipofuscinoses: Identification and characterization of differentially expressed proteins

The neuronal ceroid lipofuscinoses (NCLs) are a group of neuronal degenerative diseases that primarily affect children. Previously we hypothesized that the similarity of the phenotypes among the variant subtypes of NCL suggests that the NCLs share a common metabolic functional pathway. To test our hypothesis, we have studied several candidate proteins identified using a proteomic approach. We analyzed their differential expression and cataloged their functions and involved pathways. Forty protein peaks, differentially expressed in NCLs, were selected from two-dimensional protein fragmentation (PF2D) maps and twenty-four proteins were identified by MALDI-TOF-MS or LC–ESI-MS/MS. Six proteins were verified by further Western blotting. Our results showed that annexin A1, annexin A2, and vimentin were significantly down-regulated in NCL1, NCL2, NCL3, and NCL8 cells; galectin-1 was down-regulated in NCL1, NCL3, and NCL8 but up-regulated in NCL2 cells; and isoform 5 of caldesmon was up-regulated in all NCL cell types. The histone 2B was down-regulated in NCL3. Functional analysis showed that the differentially expressed proteins identified by PF2D could be grouped into categories of intermediate filaments, cell motility, apoptosis, cytoskeleton, membrane trafficking, calcium binding, nucleosome assembly, pigment granule and cell development. Immunocytochemistry revealed nuclear translocalization of annexin A1 in CLN2-deficient fibroblasts and abnormal distribution of l-caldesmon in cultured CLN1, CLN2, CLN3 and CLN8-deficient fibroblasts. Finding differentially expressed proteins in variant NCLs, which showed disturbances of cytoskeleton, RAGE-dependent cellular pathways and decreased glycolysis provides evidence supporting our hypothesis. These findings may contribute to the discovery of molecular biomarkers and may help further elucidate the pathogenic mechanisms underlying the NCLs.

The neuronal ceroid lipofuscinoses: the same, but different?

The NCLs (neuronal ceroid lipofuscinoses) (also known as Batten disease) are a group of at least ten fatal inherited storage disorders. Despite the identification of many of the disease-causing genes, very little is known about the underlying disease mechanisms. However, now that we have mouse or large-animal models for most forms of NCL, we can investigate pathogenesis and compare what happens in the brain in different types of the disease. Broadly similar neuropathological themes have emerged, including the highly selective nature of neuron loss, early effects upon the presynaptic compartment, together with an early and localized glial activation. These events are especially pronounced within the thalamocortical system, but it is clear that where and when they occur varies markedly between different forms of NCL. It is now becoming apparent that, despite having pathological endpoints that resemble one another, these are reached by a sequence of events that is specific to each subtype of NCL.

Neuronale Zeroidlipofuszinosen (NCL) im Tiermodell

Neuronal ceroid lipofuscinoses (NCL) are severe neurodegenerative diseases leading to early death. They belong to the group of lysosomal storage diseases. Epileptic seizures, dementia and motor deficits are frequent symptoms which are to be found prior to a total dismantling of personality and death. At present 10 subtypes of NCL can be distinguished from which the genetic defect is known in eight. The encoded proteins are soluble or membrane proteins whose function is still unclear in most cases. The investigation of the pathology and pathophysiology of NCL is highly dependent on animal models. Mouse models existing for all forms with a known genetic defect play a prominent role. Unfortunately, the retinal phenotype of some mouse models is milder than in humans rendering the appreciation of a positive therapeutic effect more difficult. Because of the severity of NCL, therapy strategies only established in a mouse model will be transferred to humans very quickly.

A novel mutation in the MFSD8 gene in late infantile neuronal ceroid lipofuscinosis

Neuronal ceroid lipofuscinoses (NCL) are lysosomal storage disorders and constitute the most common group of progressive neurodegenerative diseases in childhood. Most NCLs are inherited in a recessive manner and are clinically characterised by a variable age at onset, epileptic seizures, psychomotor decline, visual impairment and premature death. To date, eight causative genes have been identified to underlie various clinical forms of NCL. We performed a genome-wide linkage analysis followed by sequencing the recently described NCL gene MFSD8 in three affected and three unaffected members of a consanguineous Egyptian family with an autosomal recessively inherited progressive neurodegenerative disorder. The clinical picture of the patients was compatible with a late infantile NCL (LINCL); however, impairment of the visual system was not a cardinal symptom in the respective family. By linkage analysis, we identified two putative loci on chromosome 1p36.11-p35.1 and 4q28.1-q28.2. The latter locus (4q28.1-q28.2) contained the MFSD8 gene, comprising a novel homozygous missense mutation in exon 5 (c.362a>g /p.Tyr121Cys), which segregated with the disease in the three affected sibs. We describe a novel mutation in the previously identified MFSD8 gene in a family with a common phenotype of LINCL, but no clinical report of vision loss. Our results enlarge the mutational and perhaps the nosological spectrum of one of the recently identified subtypes of NCL, called CLN7.

From locus to cellular disturbances: positional cloning of the infantile neuronal ceroid lipofuscinosis gene.

Neuronal ceroid lipofuscinoses (NCL) represent a group of common progressive encephalopathies of children with a global incidence of 1 in 12,500. NCL are divided into three autosomal recessive subtypes, all assigned to different chromosomal loci. The infantile subtype of NCL (INCL) is characterized by early visual loss and mental deterioration, and leads to a vegetative state of the patients by 3 years of age. We pursued the identification of the gene defective in INCL, enriched in the Finnish population by a positional cloning approach and identified mutations in the palmitoyl-protein thioesterase (PPT) gene in INCL patients. We have further shown that PPT represents a novel lysosomal enzyme and is routed to the lysosomes via the mannose 6-phosphate receptor-mediated pathway. The worldwide most common mutation in the PPT gene, INCLFin, results in the deficient routing of the mutant PPT to lysosomes and undetectable enzyme activity in the brain tissue of patients. Our results suggest that INCL can be classified as a new member of lysosomal enzyme deficiencies.

Mutations in the palmitoyl protein thioesterase gene causing infantile neuronal ceroid lipofuscinosis.

Neuronal ceroid lipofuscinoses (NCL) represent a group of common progressive encephalopathies of children which have a global incidence of 1 in 12,500. These severe brain diseases are divided into three autosomal recessive subtypes, assigned to different chromosomal loci. The infantile subtype of NCL (INCL), linked to chromosome 1p32, is characterized by early visual loss and rapidly progressing mental deterioration, resulting in a flat electroencephalogram by 3 years of age; death occurs at 8 to 11 years, and characteristic storage bodies are found in brain and other tissues at autopsy. The molecular pathogenesis underlying the selective loss of neurons of neocortical origin has remained unknown. Here we report the identification, by positional candidate methods, of defects in the palmitoyl-protein thioesterase gene in all 42 Finnish INCL patients and several non-Finnish patients. The most common mutation results in intracellular accumulation of the polypeptide and undetectable enzyme activity in the brain of patients.

Prenatal Ultrastructural Diagnosis in the Neuronal ceroid-lipofuscinoses

The neuronal ceroid-lipofuscinoses (NCL) are autosomal-recessive disorders in childhood of unknown enzymatic origin. They can be recognized by the presence of abnormal lipopigments identified by electron microscopy. Based on the study of circulating lymphocytes, individual clinical subtypes of NCL can be correlated. Prenatal diagnosis of NCL with the electron microscope is now feasible for the infantile (Finnish) from (INCL) and late-infantile form (LINCL). INCL-specific granular lipopigments are present in endothelial cells of biopsied chorion stroma vessels of homozygously affected fetuses. In LINCL, disease-typical curvilinear bodies can be identified in uncultured amniotic fluid cells. Prenatal ultrastructural recognition of juvenile NCL (JNCL) is still controversial as only one single case has been reported. Electron microscopic findings can also be corroborated by genetic analysis in INCL and JNCL because the defective genes have been localized to chromosomes 1 and 16, respectively, but not in LINCL. Documentation of the index patients in the family is essential before prenatal diagnosis, and post-abortive confirmation of fetal NCL is also desirable.

Ultrastructural pathology of lymphocytes in neuronal ceroid-lipofuscinoses

Lymphocytes were studied by electron microscopy in five cases of neuronal ceroid-lipofuscinoses (NCL), one of infantile, three of late infantile and one of juvenile types. Each type of NCL revealed specific cytoplasmic inclusions, namely, granular bodies in the infantile form, curvilinear profiles in the late infantile form and fingerprint profiles within vacuoles in the juvenile type. Survey of the literature also confirmed the high correlation between subtype of NCL and type of lymphocytic inclusion. The electron microscopic examination lymphocytes offers easily available diagnostic informations.