Late Infantile Batten Disease Research Articles

Acidified drinking water improves motor function, prevents tremors and changes disease trajectory in Cln2R207X mice, a model of late infantile Batten disease

Batten disease is a group of mostly pediatric neurodegenerative lysosomal storage disorders caused by mutations in the CLN1–14 genes. We have recently shown that acidified drinking water attenuated neuropathological changes and improved motor function in the Cln1R151X and Cln3−/− mouse models of infantile CLN1 and juvenile CLN3 diseases. Here we tested if acidified drinking water has beneficial effects in Cln2R207X mice, a nonsense mutant model of late infantile CLN2 disease. Cln2R207X mice have motor deficits, muscle weakness, develop tremors, and die prematurely between 4 and 6 months of age. Acidified water administered to Cln2R207X male mice from postnatal day 21 significantly improved motor function, restored muscle strength and prevented tremors as measured at 3 months of age. Acidified drinking water also changed disease trajectory, slightly delaying the death of Cln2R207X males and females. The gut microbiota compositions of Cln2R207X and wild-type male mice were markedly different and acidified drinking water significantly altered the gut microbiota of Cln2R207X mice. This suggests that gut bacteria might contribute to the beneficial effects of acidified drinking water. Our study demonstrates that drinking water is a major environmental factor that can alter disease phenotypes and disease progression in rodent disease models.

Adeno-associated virus vectors and neurotoxicity-lessons from preclinical and human studies.

Over 15 years after hepatotoxicity was first observed following administration of an adeno-associated virus (AAV) vector during a hemophilia B clinical trial, recent reports of treatment-associated neurotoxicity in animals and humans have brought the potential impact of AAV-associated toxicity back to prominence. In both pre-clinical studies and clinical trials, systemic AAV administration has been associated with neurotoxicity in peripheral nerve ganglia and spinal cord. Neurological signs have also been seen following direct AAV injection into the brain, both in non-human primates and in a clinical trial for late infantile Batten disease. Neurotoxic events appear variable across species, and preclinical animal studies do not fully predict clinical observations. Accumulating data suggest that AAV-associated neurotoxicity may be underdiagnosed and may differ between species in terms of frequency and/or severity. In this review, we discuss the different animal models that have been used to demonstrate AAV-associated neurotoxicity, its potential causes and consequences, and potential approaches to blunt AAV-associated neurotoxicity.

Upregulation of tripeptidyl-peptidase 1 by 3-hydroxy-(2,2)-dimethyl butyrate, a brain endogenous ligand of PPARα: Implications for late-infantile Batten disease therapy.

The late-infantile Batten disease or late-infantile neuronal ceroid lipofuscinosis (LINCL) is an autosomal recessive lysosomal storage disorder caused by mutations in the Cln2 gene leading to deficiency of lysosomal enzyme tripeptidyl peptidase 1 (TPP1). At present, available options for this fatal disorder are enzyme replacement therapy and gene therapy, which are extensively invasive and expensive. Our study demonstrates that 3-hydroxy-(2,2)-dimethyl butyrate (HDMB), a brain endogenous molecule, is capable of stimulating TPP1 expression and activity in mouse primary astrocytes and a neuronal cell line. HDMB activated peroxisome proliferator-activated receptor-α (PPARα), which, by forming heterodimer with Retinoid X receptor-α (RXRα), transcriptionally upregulated the Cln2 gene. Moreover, by using primary astrocytes from wild type, PPARα-/- and PPARβ-/- mice, we demonstrated that HDMB specifically required PPARα for inducing TPP1 expression. Finally, oral administration of HDMB to Cln2 heterozygous (Cln2+/-) mice led to a marked upregulation of TPP1 expression in the motor cortex and striatum in a PPARα-dependent fashion. Our study suggests that HDMB, a brain endogenous ligand of PPARα, might have therapeutic importance for LINCL treatment.

Rapid and Progressive Regional Brain Atrophy in CLN6 Batten Disease Affected Sheep Measured with Longitudinal Magnetic Resonance Imaging.

Variant late-infantile Batten disease is a neuronal ceroid lipofuscinosis caused by mutations in CLN6. It is a recessive genetic lysosomal storage disease characterised by progressive neurodegeneration. It starts insidiously and leads to blindness, epilepsy and dementia in affected children. Sheep that are homozygous for a natural mutation in CLN6 have an ovine form of Batten disease Here, we used in vivo magnetic resonance imaging to track brain changes in 4 unaffected carriers and 6 affected Batten disease sheep. We scanned each sheep 4 times, between 17 and 22 months of age. Cortical atrophy in all sheep was pronounced at the baseline scan in all affected Batten disease sheep. Significant atrophy was also present in other brain regions (caudate, putamen and amygdala). Atrophy continued measurably in all of these regions during the study. Longitudinal MRI in sheep was sensitive enough to measure significant volume changes over the relatively short study period, even in the cortex, where nearly 40% of volume was already lost at the start of the study. Thus longitudinal MRI could be used to study the dynamics of progression of neurodegenerative changes in sheep models of Batten disease, as well as to assess therapeutic efficacy.

2-Hydroxypropyl-β-cyclodextrin Promotes Transcription Factor EB-mediated Activation of Autophagy

2-Hydroxypropyl-β-cyclodextrin (HPβCD) is a Food and Drug Administration-approved excipient used to improve the stability and bioavailability of drugs. Despite its wide use as a drug delivery vehicle and the recent approval of a clinical trial to evaluate its potential for the treatment of a cholesterol storage disorder, the cellular pathways involved in the adaptive response that is activated upon exposure to HPβCD are still poorly defined. Here, we show that cell treatment with HPβCD results in the activation of the transcription factor EB, a master regulator of lysosomal function and autophagy, and in enhancement of the cellular autophagic clearance capacity. HPβCD administration promotes transcription factor EB-mediated clearance of proteolipid aggregates that accumulate due to inefficient activity of the lysosome-autophagy system in cells derived from a patient with a lysosomal storage disorder. Interestingly, HPβCD-mediated activation of autophagy was found not to be associated with activation of apoptotic pathways. This study provides a mechanistic understanding of the cellular response to HPβCD treatment, which will inform the development of safe HPβCD-based therapeutic modalities and may enable engineering HPβCD as a platform technology to reduce the accumulation of lysosomal storage material.

A Hitchhiker's Guide to the Blood–brain Barrier: In Trans Delivery of a Therapeutic Enzyme

Enzyme replacement therapy (ERT) for the systemic disease associated with lysosomal storage disorders (LSDs) has been an unequivocal success.1 Unfortunately, similar success has not been realized for the central nervous system (CNS) pathology associated with LSDs—in large part because the intravenously administered lysosomal enzymes are unable to cross the blood–brain barrier (BBB). In this issue of Molecular Therapy, Meng et al. report their achievement of supraphysiological levels of the lysosomal enzyme tripeptidyl peptidase I (TPP1) in the brains of young adult mice with the neurodegenerative LSD known as late infantile neuronal ceroid lipofuscinosis (LINCL; late infantile Batten disease).2 Remarkably, therapeutic levels of activity in the brain were achieved following an intravenous injection in young adult animals with an intact BBB. This was accomplished via coinjection of TPP1 and a carrier peptide capable of crossing the BBB.3 The enzyme and carrier peptide were not covalently linked, suggesting that this approach could be useful for a wide range of CNS disorders. Although both the safety and applicability of this approach to other systems must be determined, it could represent an important step forward for the delivery of large molecules across the BBB.

Timing of Therapeutic Intervention Determines Functional and Survival Outcomes in a Mouse Model of Late Infantile Batten Disease

Classical late infantile neuronal ceroid lipofuscinosis (cLINCL) is a monogenic disorder caused by the loss of tripeptidyl peptidase 1 (TPP1) activity as a result of mutations in CLN2. Absence of TPP1 results in lysosomal storage with an accompanying axonal degeneration throughout the central nervous system (CNS), which leads to progressive neurodegeneration and early death. In this study, we compared the efficacies of pre- and post-symptomatic injections of recombinant adeno-associated virus (AAV) for treating the cellular and functional abnormalities of CLN2 mutant mice. Intracranial injection of AAV1-hCLN2 resulted in widespread human TPP1 (hTPP1) activity in the brain that was 10-100-fold above wild-type levels. Injections before disease onset prevented storage and spared neurons from axonal degeneration, reflected by the preservation of motor function. Furthermore, the majority of CLN2 mutant mice treated pre-symptomatically lived for at least 330 days, compared with a median survival of 151 days in untreated CLN2 mutant controls. In contrast, although injection after disease onset ameliorated lysosomal storage, there was evidence of axonal degeneration, motor function showed limited recovery, and the animals had a median lifespan of 216 days. These data illustrate the importance of early intervention for enhanced therapeutic benefit, which may provide guidance in designing novel treatment strategies for cLINCL patients.

Diagnosis of Neuronal Ceroid Lipofuscinosis (Batten Disease) by Electron Microscopy in Peripheral Blood Specimens

Neuronal ceroid lipopofuscinosis (Batten disease, NCL) represents a group of common childhood neurodegenerative diseases with a shared feature of deposition of abnormal metabolic products in neurons and other tissues, including peripheral blood lymphocytes. In most forms of NCL no specific enzyme defect is known and the diagnosis relies primarily on ultrastructural identification of characteristic membrane-bound inclusions containing the abnormal metabolic product. All buffy-coat specimens examined during a 7-year period (1997–2004) for the exclusion or confirmation of the diagnosis NCL were reviewed. From a total of 265 samples, 9 were inadequate and NCL was diagnosed in 56. Five showed granular osmophilic deposits of infantile Batten disease (NCL1), 10 showed curvilinear profiles of classical late infantile Batten disease (NCL2), and 17 showed vacuolated lymphocytes with fingerprint profiles, indicating classical juvenile Batten disease (NCL3). 24 samples (43%) demonstrated compact electron-dense deposits with fingerprint profiles in the absence of vacuolated lymphocytes, indicative of variant forms NCL. Ultrastructual examination of peripheral blood allows reliable and specific diagnosis of subtypes of Batten disease, including variants, and is a useful, minimally invasive test for the diagnosis of NCL in childhood.

Bone marrow transplantation in late infantile Batten disease and juvenile Batten disease.

Two patients, one each with LINCL and JNCL, underwent BMT in an attempt to alter the course of their disease. The LINCL patient received two transplants, one when asymptomatic, which was rapidly rejected, and a second BMT at age 3 years 9 months when the EEG had become abnormal. He has deteriorated in the following 2 years and now has only a few words, limited vision and feeding difficulties. Only two major seizures have occurred, but minor seizures are frequent. Although he is less severely affected than his sister at the same age, it is difficult to know if BMT has had any effect. The most significant difference is the relative mildness of seizure activity. The JNCL patient, transplanted at 8 years, when her visual problems had already started, is still in mainstream school, has good speech and good quality of life at age 9 1/2 years. No regression has been found, but EEG changes are now present and her vision has further deteriorated. The effect of BMT, if any, will not become apparent for several years in the more slowly progressive JNCL.

Tissue culture loading test with storage granules from animal models of neuronal ceroid‐lipofuscinosis (Batten disease): Testing their lysosomal degradability by normal and Batten cells

Storage granules (SGs) from ovine and canine models of Batten disease were found to be easily phagocytosed by four cell types studied. The cell types tested were human fibroblasts and peripheral monocytes (control and from a late infantile Batten disease patient), rat C6 cell line, and neonatal cardiomyocytes. The phagocytosed SGs elicited an increase in acid phosphatase activity which was localized in the phagolysosome. After phagocytosis SGs were followed for various times ranging from 7 to 21 days and were found to be of unchanged density (phase contrast), autofluorescence, and ultrastructural appearance. These findings point to their undergradability, or very low degree of degradability, in phagolysosomes in both normal or Batten cultured cells. The Batten disease SGs are not toxic and did not cause any adverse affect on the host cells. Either the normal clearance rate from lysosomes is too slow to be measured by this technique or subunit c accumulation in lysosomes need not result from a primary lysosomal protease defect. Subunit c may aggregate, because of the lack of some normally preventive factor, resulting in a physical barrier to the degradation of this highly apolar molecule.

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.

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.