Batten Disease Patients Research Articles

Long-term progression of retinal degeneration in a preclinical model of CLN7 Batten disease as a baseline for testing clinical therapeutics.

Batten disease is characterized by cognitive and motor impairment, retinal degeneration, and seizures leading to premature death. Recent studies have shown efficacy for a gene therapy approach for CLN7 Batten disease. This gene therapy approach is promising to treat cognitive and motor impairment, but is not likely to delay vision loss. Additionally, the natural progression of retinal degeneration in CLN7 Batten disease patients is not well-known. We performed visual examinations on five patients with CLN7 Batten disease and found that patients were far progressed in degeneration within their first five years of life. To better understand the disease progression, we characterized the retina of a preclinical mouse model of CLN7 Batten disease, through the age at which mice present with paralysis and premature death. We found that this preclinical model shows signs of photoreceptor to bipolar synaptic defects early, and displays rod-cone dystrophy with late loss of bipolar cells. This vision loss could be followed not only via histology, but using clinical live imaging similar to that used in human patients. Natural history studies of rare paediatric neurodegenerative conditions are complicated by the rapid degeneration and limited availability of patients. Characterization of degeneration in the preclinical model allows for future experiments to better understand the mechanisms underlying the retinal disease progression in order to find therapeutics to treat patients, as well as to evaluate these therapeutic options for future human clinical trials. Van Sickle Family Foundation Inc., NIHP30EY030413, Morton Fichtenbaum Charitable Trust and 5T32GM131945-03.

Application of Anticonvulsants, Antiepileptic Drugs, and Vitamin C in the Treatment and Analysis of Batten Disease.

Batten disease is a rare group of neurological diseases, specifically called neuronal ceroid lipofuscinosis. This is a genetic disorder and usually manifests during childhood. Batten disease is fatal and there is currently no proven cure. However, there are certain treatment methods that show potential in mitigating the aftermath of the disease. This review will explore the application and effectiveness of antiepileptic drugs, anticonvulsants, and vitamin C in multiple scenarios to treat Batten disease. Anticonvulsants are a broad group of medications that are used to treat epileptic seizures. Epileptic seizures are a big indicator of Batten disease, making anticonvulsants a potential treatment for Batten disease patients. Antiepileptic drugs also work to stop seizures by decreasing neurological excitation, thus for the same reason are often grouped alongside anticonvulsants and are being investigated as a promising way to help Batten disease patients. Vitamin C helps maintain the integrity of several intracellular processes in the central nervous system, which makes it a possible candidate for treating Batten disease. The known effects of anticonvulsants, antiepileptic drugs, and vitamin C on Batten disease are very limited and should be considered more often by healthcare professionals because of their potential effects on patients with Batten disease.

Neuronal Ceroid Lipofuscinosis Type 6 (CLN6) clinical findings and molecular diagnosis: Costa Rica\u2019s experience

BackgroundCommonly known as Batten disease, the neuronal ceroid lipofuscinoses (NCLs) are a genetically heterogeneous group of rare pediatric lysosomal storage disorders characterized by the intracellular accumulation of autofluorescent material (known as lipofuscin), progressive neurodegeneration, and neurological symptoms. In 2002, a disease-causing NCL mutation in the CLN6 gene was identified (c.214G > T) in the Costa Rican population, but the frequency of this mutation among local Batten disease patients remains incompletely characterized, as do clinical and demographic attributes for this rare patient population.ObjectiveTo describe the main sociodemographic and clinical characteristics of patients with a clinical diagnosis for Batten Disease treated at the National Children's Hospital in Costa Rica and to characterize via molecular testing their causative mutations.MethodsDNA extracted from buccal swabs was used for CLN6 gene sequencing. Participants’ sociodemographic and clinical characteristics were also obtained from their medical records.ResultsNine patients with a clinical diagnosis of Batten disease were identified. Genetic sequencing determined the presence of the previously described Costa Rican homozygous mutation in 8 of 9 cases. One patient did not have mutations in the CLN6 gene. In all cases where the Costa Rican CLN6 mutation was present, it was accompanied by a substitution in intron 2. Patients were born in 4 of the 7 Costa Rican provinces, with an average onset of symptoms close to 4 years of age. No parental consanguinity was present in pedigrees. Initial clinical manifestations varied between patients but generally included: gait disturbances, language problems, visual impairment, seizures and psychomotor regression. Cortical and cerebellar atrophy was a constant finding when neuroimaging was performed. Seizure medication was a common element of treatment regimens.ConclusionsThis investigation supports that the previously characterized c.214G > T mutation is the most common causative NCL mutation in the Costa Rican population. This mutation is geographically widespread among Costa Rican NCL patients and yields a clinical presentation similar to that observed for CLN6 NCL patients in other geographies.

Alpha-fetoprotein is an autoantigen in hepatocellular carcinoma and juvenile Batten disease.

Failure of immune tolerance leads to production of autoantibodies to self-antigens. The repertoire of autoantibodies detected in cancer patients can indicate the presence of autoimmune disease. Alpha-fetoprotein (AFP) autoantibodies have been found in patients withhepatocellular carcinoma (HCC) and in juvenile Batten disease (BD), a neurodegenerative condition involving autoimmunity. Variant conformational forms of AFP together with exposed occult antigenic determinant sites on the AFP polypeptide resemble the features of a disordered proteinwhich can impair central immune tolerance. These aberrant structural protein forms can lead to the persistence of autoantibody production byimmune sensitized B-lymphocytes. Thus, it is not surprisingthat AFP, a self-antigen, can induce autoimmune responses in humans. Herein, we discuss the molecularand antigenic properties of AFP which make it a disordered protein, and its ability to induce autoantibody production to AFP cryptic epitopes in both HHC and BDpatients. Such insights might aid in the future design of AFP-based vaccines and to discovery of novel pathogenic mechanisms of autoimmune diseases which demonstrate the presence of denatured intermediate forms of AFP.

Changes in motor behavior, neuropathology, and gut microbiota of a Batten disease mouse model following administration of acidified drinking water

CLN3 mutations cause the fatal neurodegenerative disorder, CLN3 Batten disease. The Cln3−/− mouse model displays characteristic features of the human disease including motor deficits. When mice received acidified drinking water (pH 2.5–2.9) instead of normal tap water (pH 8.4) for several generations, the motor skills of Cln3−/− mice normalized to control levels, indicating a disease-modifying effect of acidified water. Here we investigated if acidified water administered from postnatal day 21 has therapeutic benefits in Cln3−/− mice. Indeed, acidified water temporarily attenuated the motor deficits, had beneficial effects on behavioral parameters and prevented microglial activation in the brain of Cln3−/− mice. Interestingly, in control mice, acidified drinking water caused brain region-specific glial activation and significant changes in motor performance. Since the gut microbiota can influence neurological functions, we examined it in our disease model and found that the gut microbiota of Cln3−/− mice was markedly different from control mice, and acidified water differentially changed the gut microbiota composition in these mice. These results indicate that acidified water may provide therapeutic benefit to CLN3 Batten disease patients, and that the pH of drinking water is a major environmental factor that strongly influences the results of murine behavioral and pathological studies.

Cell cycle arrest in Batten disease lymphoblast cells

Batten disease is an inherited neurodegenerative disorder caused by a CLN3 gene mutation. Batten disease is characterized by blindness, seizures, cognitive decline, and early death. Although apoptotic cell death is one of the pathological hallmarks of Batten disease, little is known about the regulatory mechanism of apoptosis in this disease. Since the CLN3 gene is suggested to be involved in the cell cycle in a yeast model, we investigated the cell cycle profile and its regulatory factors in lymphoblast cells from Batten disease patients. We found G1/G0 cell cycle arrest in Batten disease cells, with overexpression of p21, sphingosine, glucosylceramide, and sulfatide as possible cell cycle regulators.

Age-dependent therapeutic effect of memantine in a mouse model of juvenile Batten disease

Currently there is no treatment for juvenile Batten disease, a fatal childhood neurodegenerative disorder caused by mutations in the CLN3 gene. The Cln3-knockout (Cln3Δex1-6) mouse model recapitulates several features of the human disorder. Cln3Δex1-6 mice, similarly to juvenile Batten disease patients, have a motor coordination deficit detectable as early as postnatal day 14. Previous studies demonstrated that acute attenuation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-type glutamate receptor activity by the non-competitive AMPA antagonist, EGIS-8332, in both 1- and 6–7-month-old Cln3Δex1-6 mice results in improvement in motor coordination. Here we show that acute inhibition of N-methyl-d-aspartate (NMDA)-type glutamate receptors by memantine (1 and 5 mg/kg i.p.) had no effect on the impaired motor coordination of one-month-old Cln3Δex1-6 mice. At a later stage of the disease, in 6–7-month-old Cln3Δex1-6 mice, memantine induced a delayed but extended (8 days) improvement of motor skills similarly to that observed previously with EGIS-8332 treatment. An age-dependent therapeutic effect of memantine implies that the pathomechanism in juvenile Batten disease changes during disease progression. In contrast to acute treatment, repeated administration of memantine or EGIS-8332 (1 mg/kg, once a week for 4 weeks) to 6-month-old Cln3Δex1-6 mice had no beneficial effect on motor coordination. Moreover, repeated treatments did not impact microglial activation or the survival of vulnerable neuron populations. Memantine did not affect astrocytosis in the cortex. EGIS-8332, however, decreased astrocytic activation in the somatosensory barrelfield cortex.Acute inhibition of NMDA receptors can induce a prolonged therapeutic effect, identifying NMDA receptors as a new therapeutic target for juvenile Batten disease.

The yeast Batten disease orthologue Btn1 controls endosome–Golgi retrograde transport via SNARE assembly

The human Batten disease gene CLN3 and yeast orthologue BTN1 encode proteins of unclear function. We show that the loss of BTN1 phenocopies that of BTN2, which encodes a retromer accessory protein involved in the retrieval of specific cargo from late endosomes (LEs) to the Golgi. However, Btn1 localizes to Golgi and regulates soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor (SNARE) function to control retrograde transport. Specifically, BTN1 overexpression and deletion have opposing effects on phosphorylation of the Sed5 target membrane SNARE, on Golgi SNARE assembly, and on Golgi integrity. Although Btn1 does not interact physically with SNAREs, it regulates Sed5 phosphorylation by modulating Yck3, a palmitoylated endosomal kinase. This may involve modification of the Yck3 lipid anchor, as substitution with a transmembrane domain suppresses the deletion of BTN1 and restores trafficking. Correspondingly, deletion of YCK3 mimics that of BTN1 or BTN2 with respect to LE-Golgi retrieval. Thus, Btn1 controls retrograde sorting by regulating SNARE phosphorylation and assembly, a process that may be adversely affected in Batten Disease patients.

Btn3 is a negative regulator of Btn2-mediated endosomal protein trafficking and prion curing in yeast

Yeast Btn2 facilitates the retrieval of specific proteins from late endosomes (LEs) to the Golgi, a process that may be adversely affected in Batten disease patients. We isolated the putative yeast orthologue of a human complex I deficiency gene, designated here as BTN3, as encoding a Btn2-interacting protein and negative regulator. First, yeast overexpressing BTN3 phenocopy the deletion of BTN2 and mislocalize certain trans-Golgi proteins, like Kex2 and Yif1, to the LE and vacuole, respectively. In contrast, the deletion of BTN3 results in a tighter pattern of protein localization to the Golgi. Second, BTN3 overexpression alters Btn2 localization from the IPOD compartment, which correlates with a sharp reduction in Btn2-mediated [URE3] prion curing. Third, Btn3 and the Snc1 v-SNARE compete for the same binding domain on Btn2, and this competition controls Btn2 localization and function. The inhibitory effects upon protein retrieval and prion curing suggest that Btn3 sequesters Btn2 away from its substrates, thus down-regulating protein trafficking and aggregation. Therefore Btn3 is a novel negative regulator of intracellular protein sorting, which may be of importance in the onset of complex I deficiency and Batten disease in humans.

Identification of α-fetoprotein as an autoantigen in juvenile Batten disease

Humoral autoimmunity against glutamic acid decarboxylase has been described in juvenile Batten disease patients and in the Cln3(-/-) mouse model. To obtain a more comprehensive understanding of the repertoire of antigens targeted, we examined the reactivity of Cln3(-/-) mouse sera to brain proteins from fetal, postnatal and adult rats. Among the candidate antigens identified was alpha-fetoprotein (AFP), a protein that has altered expression in several nervous system disorders and hepatic malignancies. Moreover, AFP levels were upregulated in the brains and livers of postnatal day 14 Cln3(-/-) animals. Sera from 31 juvenile Batten disease patients revealed the presence of anti-AFP autoantibodies in juvenile Batten disease male patients (12/13) and female patients (8/18). While these findings provide more evidence that autoimmunity is an active component of juvenile Batten disease, the gender-apparent difference evidenced by patients with regard anti-AFP antibodies may underlie variation in progression and clinical manifestations in this disorder.

Selectively increased sensitivity of cerebellar granule cells to AMPA receptor-mediated excitotoxicity in a mouse model of Batten disease

Batten disease, a lysosomal storage disorder, is caused by mutations in the CLN3 gene. The Cln3-knockout (Cln3-/-) mouse model of the disease exhibits many characteristic pathological features of the human disorder. Here, we show that Cln3-/- mice, similarly to Batten disease patients, have a deficit in cerebellar motor coordination. To explore the possible cellular cause of this functional impairment, we compared the vulnerability of wild type (WT) and Cln3-/- cerebellar granule cell cultures to different toxic insults. We have found that cultured Cln3-/- cerebellar granule cells are selectively more vulnerable to AMPA-type glutamate receptor-mediated toxicity than their WT counterparts. This selective sensitivity was also observed in organotypic cerebellar slice cultures. Our results suggest that lack of the CLN3 protein has a significant influence on the function of AMPA receptors in cerebellar granule neurons, and that AMPA receptor dysregulation may be a major contributor to the cerebellar dysfunction in Batten disease.

Deletion of the Caenorhabditis elegans homologues of the CLN3 gene, involved in human juvenile neuronal ceroid lipofuscinosis, causes a mild progeric phenotype

The CLN3 gene is involved in juvenile neuronal ceroid lipofuscinosis (JNCL), or Batten-Spielmeyer-Vogt disease, a severe hereditary neurodegenerative lysosomal storage disorder characterized by progressive disease pathology, with loss of vision as the first symptom. Another characteristic of JNCL is the lysosomal accumulation of autofluorescent lipopigments, forming fingerprint storage patterns visible by electron microscopy. The function of the CLN3 protein is still unknown, although the evolutionarily conserved CLN3 protein is being functionally analysed using different experimental models. We have explored the potential of the nematode Caenorhabditis elegans as a model for Batten disease in order to bridge the gap between the unicellular yeast and very complex mouse JNCL models. C. elegans has three genes homologous to CLN3, for each of which deletion mutants were isolated. Cln-3.1 deletion mutants have a decreased lifespan, and cln-3.2 deletion mutants a decreased brood size. However, the neuronal or movement defects and aberrant lipopigment distribution or accumulation observed in JNCL were not found in the worms. To detect possible redundancy, single deletion mutants were crossed to obtain double and triple mutants, which were viable but showed no JNCL-specific defects. The cln-3 triple mutants show a more prominent decrease in lifespan and brood size, the latter most conspicuously at the end of the egg-laying period, suggesting premature ageing. To focus our functional analysis we examined the C. elegans cln-3 expression patterns, using promoter-GFP (green fluorescent protein) gene fusions. Fluorescence patterns suggest cln-3.1 expression in the intestine, cln-3.2 expression in the hypoderm, and cln-3.3 expression in intestinal muscle, male-specific posterior muscle and hypoderm. Further life stage- and tissue-specific analysis of the processes causing the phenotype of the cln-3 triple mutants may provide more information about the function of the cln-3 protein and contribute to a better understanding of the basic processes affected in Batten disease patients.

Analysis of CLN3-protein interactions using the yeasttwo-hybrid system

Juvenile neuronal ceroid lipofuscinosis (Batten disease) is a childhood neurodegenerative disease that is caused by mutations in the CLN3 gene. The protein encoded by CLN3 has no homology with any proteins of known function and its cellular role remains elusive. In order to investigate the role played by the CLN3 protein we aimed to identify interacting proteins. Here, we describe the yeast two-hybrid system as the approach taken to investigate such protein-protein interactions. CLN3 was expressed as a fusion protein with a DNA-binding domain and used to screen a library of human fetal brain cDNAs fused to a transcriptional activation domain. Owing to low level expression of the full length CLN3 fusion protein, truncated regions corresponding to the predicted hydrophilic regions were also tested. No proteins that interact with CLN3 were detected, nor was there any evidence for CLN3-CLN3 interactions. Potential interaction of CLN3 with subunit c of mitochondrial ATP synthase, the major component of the storage material that accumulates in Batten disease patients, was also tested. No interaction was detected suggesting that the accumulation of subunit c does not result from loss of a process that requires a direct interaction with CLN3. We conclude that either CLN3 does not interact with other proteins or such interactions cannot be detected using the two-hybrid system.

Full-field ERG in patients with Batten/Spielmeyer-Vogt disease caused by mutations in the CLN3 gene

Purpose: To investigate, using full-field ERG, the retinal function in patients with Batten/Spielmeyer-Vogt disease caused by mutations in the CLN3 gene. Methods: Batten disease status of five patients was confirmed by the presence of vacuolated lymphocytes in peripheral blood and the identification of mutations in the Batten disease gene ( CLN3 ). Visual acuity, fundus appearance, and full-field ERG were examined in all patients (age 4-19 years). The examination was repeated in one patient after 16 months. Results: Three unrelated patients were homozygous for the most common mutation in CLN3, the 1.02 kb deletion; two patients (sisters) were heterozygous for the 1.02 kb deletion and an as yet unidentified mutation in the CLN3 gene. Full-field ERG recordings in all five patients demonstrated no rod responses and only small remaining cone responses, which could be detected with 30 Hz-flicker stimulation. Re-examination of a six-year-old girl after 16 months revealed a fast progression of the retinal degeneration. Conclusion: Full-field ERG recordings in Batten disease patients, both homozygous and heterozygous for the 1.02 kb deletion in the CLN3 gene, confirm retinal degeneration to be severe, widespread, and with a rapid progression early in the disease course. The onset of visual failure may be delayed when compared to the classic disease course, particularly in patients who are not homozygous for the most common CLN3 mutation, a 1.02 kb deletion. In that case, the disease progression in terms of other symptoms may also be further delayed.

Targeted Disruption of the Cln3 Gene Provides a Mouse Model for Batten Disease

Batten disease, a degenerative neurological disorder with juvenile onset, is the most common form of the neuronal ceroid lipofuscinoses. Mutations in the CLN3 gene cause Batten disease. To facilitate studies of Batten disease pathogenesis and treatment, a murine model was created by targeted disruption of the Cln3 gene. Mice homozygous for the disrupted Cln3 allele had a neuronal storage disorder resembling that seen in Batten disease patients: there was widespread and progressive intracellular accumulation of autofluorescent material that by EM displayed a multilamellar rectilinear/fingerprint appearance. Inclusions contained subunit c of mitochondrial ATP synthase. Mutant animals also showed neuropathological abnormalities with loss of certain cortical interneurons and hypertrophy of many interneuron populations in the hippocampus. Finally, as is true in Batten disease patients, there was increased activity in the brain of the lysosomal protease Cln2/TPP-1. Our findings are evidence that the Cln3-deficient mouse provides a valuable model for studying Batten disease.

Prenatal diagnosis of Batten's disease

Summary Background Batten's disease is the most common progressive encephalopathy of childhood in Western countries. The major mutation is a 1 kb deletion, which is carried by 81% of Batten's disease patients. We report on the use of direct gene analysis in the prenatal diagnosis of this disease. Methods and findings A Finnish woman with a son with Batten's disease came for genetic counselling for her current pregnancy. Electron microscopy of a chorionic villus sample gave suggestive findings. We used PCR to look for the intragenic microsatellite marker D16S298; 96% of Finnish Batten's disease patients carry allele 6 at this marker. The fetus and the affected son both carried the same high-risk genotype, 6/6. Both were homozygous for the 1 kb deletion. The pregnancy was terminated. Electron microscopy of the fetus showed typical Batten's disease changes. Interpretation We have successfully used direct gene analysis in the prenatal diagnosis of Batten's disease.

Batten Disease and Mitochondrial Pathways of Proteolysis

Most forms of Batten Disease (BD), a group of neurodegenerative diseases, are characterized by the accumulation within lysosomes of the very hydrophobic protein subunit 9 of the mitochondrial F1F0-ATP synthase (F-ATPase). It is now known that the cause of the accumulation of this protein in BD is a reduction in its rate of degradation. Because the F-ATPase subunit 9 accumulates within lysosomes of BD tissues, the degradative defect seemed likely to be within lysosomes. However, a recent report showed that delayed degradation of F-ATPase subunit 9 was evident in fibroblasts from BD patients long before any of the protein could be found within lysosomes. Therefore, the defective degradation pathway in BD appears likely to be intramitochondrial. We review the rather limited information about pathways of degradation of mitochondrial proteins. Mitochondria can be taken up and degraded by lysosomes through a process called macroautophagy. However, substantial proteolysis also occurs within mitochondria. Several different proteases are present within mitochondria, but their normal protein substrates are largely unknown. Like proteases from bacteria, many of these proteases operate in concert with molecular chaperones. We hypothesize that a mutation in a gene encoding a mitochondrial protease or a mitochondrial molecular chaperone leads to impaired degradation of F-ATPase subunit 9 in BD. This proteolipid may then form intracellular aggregates that are eventually sequestered into lysosomes.

Late-infantile Batten disease: purification of the subunit c of the mitochondrial ATP synthase from storage material.

The accumulation of subunit c of the mitochondrial ATP synthase in late-infantile neuronal lipofuscinosis (LINCL) and juvenile neuronal lipofuscinosis (JNCL) is well documented. The purification of the subunit from diverse sources has been reported previously, although not from the brain of Batten disease patients. This proteolipid has now been purified from late-infantile Batten disease brain. The procedures used were an original combination of the conventional solubilisation, differential centrifugation, organic solvent extractions, preparative gel electrophoresis, and FPLC. Gel filtration of the purified protein indicated molecular mass equal to or greater than 2 x 10(6) Da; however, electrophoresis of this pure protein suggested a molecular mass of approximately 3,500 Da, which is a characteristic of subunit c. The pure protein may be solubilised in aqueous buffer containing < 1% lithium dodecyl sulphate (LDS). The protein binds dicyclohexylcarbodiimide (DCCD) and shows immunoreactivity to antibodies raised against ovine storage bodies.

Batten Disease: A Model for the Study of Membrane Lipid Metabolism

Batten disease (juvenile neuronal ceroid lipofuscinosis) is a severe, untreatable, inherited neurodegenerative disease. Biochemical studies have revealed a marked deficiency of phospholipids in red cell, platelet, and cultured skin fibroblast membranes of Batten disease patients; a greater understanding of the mechanism leading to this deficiency should lead to the discovery of the basic cause of the disease. Greater understanding of the normal pathways of phospholipid metabolism will impact not only Batten disease diagnosis and therapy but also numerous other conditions that present with phospholipid abnormalities.

Presence of abnormal amounts of dolichols in the urinary sediment of Batten disease patients.

Summary: Polyisoprenols of the dolichol class have been identified in urinary sediment for the first time and quantified by a high performance liquid chromatographic method. In the late infantile and juvenile forms of Neuronal Ceroid Lipofuscinosis (Batten disease), greatly increased amounts of dolichols of C-90 to C-105 were found in the urinary sediment compared with a variety of other neurologic disorders and age-matched normal subjects. Dolichols purified from the urinary sediment of a late infantile Batten disease patient were shown to have spectroscopic and chemical properties identical to standard preparations of liver and brain dolichols. Speculation: Measurement of dolichols in the urinary sediment could be of value in diagnosis and screening of siblings of Batten disease. The discovery that dolichols are present in the storage cytosomes, are increased in both the brain and dehisced renal tubular cells in the urine suggests that the basic biochemical defect in these inherited disorders lies on pathways involved in the utilization of dolichols for glycoprotein synthesis.