Lipofuscinosis Research Articles

Investigating the role of GPNMB in modulating LPS mediated inflammation in progranulin‐deficient macrophages

AbstractBackgroundProgranulin (PGRN) is a glycosylated holoprotein that is critical to endo‐lysosomal health and regulating inflammatory responses over the lifespan. Insufficient PGRN due to nonsense mutations in the GRN gene has been linked to increased risk of developing Frontotemporal Dementia (FTD) and Neuronal Ceroid Lipofuscinosis (NCL‐11). The precise mechanism(s) behind the onset and progression of disease is unclear, and no disease‐modifying treatment exists. Previous work has identified increased glycoprotein non‐metastatic B (GPNMB) in both the cortex and plastma of Grn−/− mice relative to Grn+/+ mice, and our lab has recently identified different GPNMB expression in PGRN‐deficient immune cell populations, but it remains unclear how this increase in GPNMB modifies the inflammatory response(s) with PGRN deficits. This work seeks to investigate GPNMB expression over the course of the immune response in PGRN‐deficient cells, and the extent to which GPNMB modulates inflammation.MethodTo investigate the role(s) of GPNMB in PGRN‐deficient myeloid cells, we isolated peritoneal macrophages (pMacs) from Grn+/+,and Grn−/− mice and quantified GPNMB protein before and after lipopolysaccharide (LPS) stimulation with western blot. We also determined the extent to which exposure to the GPNMB extracellular domain (ECD) modifies LPS‐elicited markers of inflammation in both Grn+/+and Grn−/‐ pMacs via qPCR. Finally, we determined how markers of inflammation were altered in pMacs from Grn−/−Gpmnb−/‐ relative to Grn+/+and Grn−/‐ with and without LPS stimulation.ResultWe determined that the additional loss of GPNMB in Grn−/−Gpmnb−/− pMacs altered the expression of inflammatory markers after LPS challenge relative to both Grn−/−and Grn+/+ pMacs. We also discovered that GPNMB is dynamically regulated during and after LPS challenge in both Grn+/+ and Grn−/− pMacs. Finally, we determined that the addition of GPNMB ECD before and during LPS treatment ameliorated the altered expression of inflammatory markers during LPS challenge.ConclusionThe increase of GPNMB expression in Grn−/‐ myeloid cells is a significant modulator of inflammatory responses and may be a potential target in the development of therapeutics.

PP19 Health Technology Assessment Reports In Brazilian Unified Health System: Number Of Potential Beneficiaries in 2022

IntroductionUniversal access to health public services was established in Brazil 32 years ago. However, health technology assessment (HTA) as a requirement for the decision-making process in the Unified Health System (SUS) was defined only in 2011 with the National Committee for Health Technology Incorporation of the SUS (Conitec), which advises the Ministry of Health on the decision to incorporate health technologies into the SUS. All of Conitec’s recommendations are based on the best available scientific evidence regarding efficacy, effectiveness, and safety of a technology, but also include economic evaluation studies of these technologies, developed from the perspective of the SUS. Considering this an estimate of the population eligible for use of the technology under evaluation, if it is incorporated into the SUS, it is considered in the decision-making process.MethodsThis descriptive study, based on open access data from Conitec’s website, aimed at identifying the estimated number of patients potentially benefitting by the recommendations published in 2022, from January to November. Since each report includes an estimate for the first five years of incorporation of the technologies, all data were collected to check whether population growth was considered.ResultsFinally, 38 recommendation reports were identified, with 28 reports on incorporation and 10 reports for expansion of technology use. Among them, they related to 31 medicines and seven procedures or products. In the first year after incorporating the listed technologies, a total of 7,767,321 potential beneficiary patients were estimated, while over five years the total number would increase to approximately 7,967,874 patients. There were recommended drugs for rare diseases whose benefited population did not exceed the estimate of 10 patients per year; as an example is cerliponase alfa for treating neuronal ceroid lipofuscinosis. In another example, an estimate of 4,494,539 women would benefit by incorporated contraceptives into the SUS.ConclusionsThis study describes how accessible public health is becoming, meeting more health policies, showing potential to benefit more patients every day and showing what trends can be expected in the future.

2438. Positive Cerebrospinal Fluid Cultures from Intraventricular Reservoirs for CLN2 Patients: One Institution's Experience

Abstract Background Enzyme replacement therapy (ERT) with cerliponase alfa (Brineura) has been shown to slow progression of milestone deterioration in Neuronal Ceroid Lipofuscinosis Type 2 (CLN2), an inherited neurodegenerative lysosomal storage disorder. Brineura must be administered intraventricularly every 2 weeks, necessitating the placement of ventricular reservoirs and requiring frequent access. Traditionally, positive cerebrospinal fluid (CSF) cultures are managed with device replacement and antibiotic treatment. We sought to establish which circumstances might allow for careful observation without device removal. In this study, we report our single-institution experience with clinical outcomes of positive CSF cultures in 16 CLN2 patients over 6 years. Methods We retrospectively reviewed a cohort of 16 patients with CLN2 disease who had ventricular reservoirs placed for ERT administration. At each ERT infusion, CSF was collected by sterile technique and cultured by both thioglycolate broth and agar plate. Epidemiologic and microbiologic data, symptomatology, total antibiotic days, removal and replacement of ventricular reservoir, hospital length of stay, and mortality were analyzed for each patient. Results In our cohort, 11 of 16 patients (69%) had at least one positive CSF culture (Fig 1). Of the 11 with positive cultures, only 3 had their device removed and replaced for a positive culture with concurrent antibiotic treatment at our center, and 2 patients subsequently have been treated with prophylactic antibiotics at infusions (Fig 2). Out of 1401 total CSF cultures, 64 (4.56%) were positive. The most common organism grown was Cutibacterium acnes, which typically grew in only broth culture (82%), suggesting low bacterial burden (Fig 3). The other 7 patients with positive cultures remained asymptomatic with no intervention required. Conclusion At our institution, we have found that in asymptomatic patients with frequently accessed ventricular reservoirs, positive CSF culture with low virulence skin flora was common, and rarely required intervention. This strategy reduced the risks of invasive surgery, prolonged antibiotic courses, and missed infusions. In the future, routine screening cultures in asymptomatic patients can be avoided. Disclosures Raymond Wang, MD, Biomarin Pharmaceutical: Advisor/Consultant|Biomarin Pharmaceutical: Grant/Research Support|Biomarin Pharmaceutical: equity interest Antonio C. Arrieta, MD, FIDSA, FPIDS, Astellas Pharma Global Development, Inc.: Advisor/Consultant|Astellas Pharma Global Development, Inc.: Grant/Research Support|Astellas Pharma Global Development, Inc.: Honoraria|Cumberland Pharmaceutical: Grant/Research Support|IDbyDNA: Advisor/Consultant|IDbyDNA: Grant/Research Support|Melinta: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|Nabriva: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support|Pfizer, Inc: Advisor/Consultant|Pfizer, Inc: Grant/Research Support|Roche/Genentech: Grant/Research Support|The Medicine Company: Grant/Research Support

Jansky-Bielschowsky Disease in 2 Moroccan Girls. Clinical Cases

Neuronal ceroid lipofuscinoses (NLCs) belong to the group of lysosomal diseases. Their transmission is autosomal recessive. They are characterized by progressive degenerative neurological damage of variable clinical expressions, and by ophthalmic damage. Jansky-Bieloschowsky disease is the classic late infantile form of CLNs or classic CLN2. The EEG tracing is characteristic. Visual and somaesthetic cortical evoked potentials are abnormal. Cerebral MRI shows cerebellar and then cerebral cortical atrophy associated with T2 hypersignal of the periventricular white matter. The diagnosis was confirmed by biochemical, histological, and molecular tests. Patient n°1 is 7 years old. She is bedridden and visually impaired. She was presented with psychomotor regression at the age of 3 and epilepsy 6 months later. Brain imaging and EEG were typical. TPP1 (tripeptidyl-peptidase1) enzyme activity was significantly reduced. Patient 2 is a 5-year-old girl who is also bedridden and visually impaired. She presented with psychomotor regression at the age of 3 years and 2 months, and epilepsy 11 months later. Brain imaging and EEG were typical, and TPP1 enzyme activity had collapsed. These two observations illustrate the diagnostic particularities of this very rare disease and current therapeutic perspectives.

Multi-modal proteomic characterization of lysosomal function and proteostasis in progranulin-deficient neurons

BackgroundProgranulin (PGRN) is a lysosomal glycoprotein implicated in various neurodegenerative diseases, including frontotemporal dementia and neuronal ceroid lipofuscinosis. Over 70 mutations discovered in the GRN gene all result in reduced expression of the PGRN protein. Genetic and functional studies point toward a regulatory role for PGRN in lysosome functions. However, the detailed molecular function of PGRN within lysosomes and the impact of PGRN deficiency on lysosomes remain unclear.MethodsWe developed multifaceted proteomic techniques to characterize the dynamic lysosomal biology in living human neurons and fixed mouse brain tissues. Using lysosome proximity labeling and immuno-purification of intact lysosomes, we characterized lysosome compositions and interactome in both human induced pluripotent stem cell (iPSC)-derived glutamatergic neurons (i3Neurons) and mouse brains. Using dynamic stable isotope labeling by amino acids in cell culture (dSILAC) proteomics, we measured global protein half-lives in human i3Neurons for the first time.ResultsLeveraging the multi-modal proteomics and live-cell imaging techniques, we comprehensively characterized how PGRN deficiency changes the molecular and functional landscape of neuronal lysosomes. We found that PGRN loss impairs the lysosome’s degradative capacity with increased levels of v-ATPase subunits on the lysosome membrane, increased hydrolases within the lysosome, altered protein regulations related to lysosomal transport, and elevated lysosomal pH. Consistent with impairments in lysosomal function, GRN-null i3Neurons and frontotemporal dementia patient-derived i3Neurons carrying GRN mutation showed pronounced alterations in protein turnover, such as cathepsins and proteins related to supramolecular polymerization and inherited neurodegenerative diseases.ConclusionThis study suggested PGRN as a critical regulator of lysosomal pH and degradative capacity, which influences global proteostasis in neurons. Beyond the study of progranulin deficiency, these newly developed proteomic methods in neurons and brain tissues provided useful tools and data resources for the field to study the highly dynamic neuronal lysosome biology.Graphical

A one-health approach to using sheep in research, with a focus on neuroscience studies

Sheep have been an important animal for both academic and basic sciences education, with a positive impact on the public health sector and, subsequently, One Health. This review presents the impact of sheep on research with a specific focus on neuroscience studies. Disorders, as well as neuroendocrine and environmental factors affecting the brain, the spinal cord, and the peripheral nervous system, are selected, and relevant research and sheep models mimicking human diseases are described. The review discusses various sheep models, encompassing prion, Parkinson’s, Alzheimer’s, Huntington’s disease, and neuronal ceroid lipofuscinoses (Batten Disease), along with ischemic stroke. Sheep play a pivotal role in elucidating the pathogenesis and/or treatment for the aforementioned diseases. Furthermore, this research is underpinned by solid neuroanatomy knowledge. Consequently, we outline the main reasons why sheep are such robust research models. In conclusion, we demonstrate the important role that sheep models fulfill in advancing the mission of the One Health Initiative.

CLN2 disease resulting from a novel homozygous deep intronic splice variant in TPP1 discovered using long-read sequencing

Neuronal ceroid lipofuscinosis type 2 (CLN2) is an autosomal recessive neurodegenerative disorder with enzyme replacement therapy available. We present two siblings with a clinical diagnosis of CLN2 disease, but no identifiable TPP1 variants after standard clinical testing. Long-read sequencing identified a homozygous deep intronic variant predicted to affect splicing, confirmed by clinical DNA and RNA sequencing. This case demonstrates how traditional laboratory assays can complement emerging molecular technologies to provide a precise molecular diagnosis.

Neuronal progenitor cells-based metabolomics study reveals dysregulated lipid metabolism and identifies putative biomarkers for CLN6 disease

Neuronal ceroid lipofuscinosis 6 (CLN6) is a rare and fatal autosomal recessive disease primarily affecting the nervous system in children. It is caused by a pathogenic mutation in the CLN6 gene for which no therapy is available. Employing an untargeted metabolomics approach, we analyzed the metabolic changes in CLN6 subjects to see if this system could potentially yield biomarkers for diagnosis and monitoring disease progression. Neuronal-like cells were derived from human fibroblast lines from CLN6-affected subjects (n = 3) and controls (wild type, n = 3). These were used to assess the potential of a neuronal-like cell-based metabolomics approach to identify CLN6 distinctive and specific biomarkers. The most impacted metabolic profile is associated with sphingolipids, glycerophospholipids metabolism, and calcium signaling. Over 2700 spectral features were screened, and fifteen metabolites were identified that differed significantly between both groups, including the sphingolipids C16 GlcCer, C24 GlcCer, C24:1 GlcCer and glycerophospholipids PG 40:6 and PG 40:7. Of note, these fifteen metabolites were downregulated in the CLN6 disease group. This study is the first to analyze the metabolome of neuronal-like cells with a pathogenic mutation in the CLN6 gene and to provide insights into their metabolomic alterations. This could allow for the development of novel biomarkers for monitoring CLN6 disease.

Loss of Depalmitoylation Disrupts Homeostatic Plasticity of AMPARs in a Mouse Model of Infantile Neuronal Ceroid Lipofuscinosis.

Protein palmitoylation is the only reversible post-translational lipid modification. Palmitoylation is held in delicate balance by depalmitoylation to precisely regulate protein turnover. While over 20 palmitoylation enzymes are known, depalmitoylation is conducted by fewer enzymes. Of particular interest is the lack of the depalmitoylating enzyme palmitoyl-protein thioesterase 1 (PPT1) that causes the devastating pediatric neurodegenerative condition infantile neuronal ceroid lipofuscinosis (CLN1). While most of the research on Ppt1 function has centered on its role in the lysosome, recent findings demonstrated that many Ppt1 substrates are synaptic proteins, including the AMPA receptor (AMPAR) subunit GluA1. Still, the impact of Ppt1-mediated depalmitoylation on synaptic transmission and plasticity remains elusive. Thus, the goal of the present study was to use the Ppt1 -/- mouse model (both sexes) to determine whether Ppt1 regulates AMPAR-mediated synaptic transmission and plasticity, which are crucial for the maintenance of homeostatic adaptations in cortical circuits. Here, we found that basal excitatory transmission in the Ppt1 -/- visual cortex is developmentally regulated and that chemogenetic silencing of the Ppt1 -/- visual cortex excessively enhanced the synaptic expression of GluA1. Furthermore, triggering homeostatic plasticity in Ppt1 -/- primary neurons caused an exaggerated incorporation of GluA1-containing, calcium-permeable AMPARs, which correlated with increased GluA1 palmitoylation. Finally, Ca2+ imaging in awake Ppt1 -/- mice showed visual cortical neurons favor a state of synchronous firing. Collectively, our results elucidate a crucial role for Ppt1 in AMPAR trafficking and show that impeded proteostasis of palmitoylated synaptic proteins drives maladaptive homeostatic plasticity and abnormal recruitment of cortical activity in CLN1.SIGNIFICANCE STATEMENT Neuronal communication is orchestrated by the movement of receptors to and from the synaptic membrane. Protein palmitoylation is the only reversible post-translational lipid modification, a process that must be balanced precisely by depalmitoylation. The significance of depalmitoylation is evidenced by the discovery that mutation of the depalmitoylating enzyme palmitoyl-protein thioesterase 1 (Ppt1) causes severe pediatric neurodegeneration. In this study, we found that the equilibrium provided by Ppt1-mediated depalmitoylation is critical for AMPA receptor (AMPAR)-mediated plasticity and associated homeostatic adaptations of synaptic transmission in cortical circuits. This finding complements the recent explosion of palmitoylation research by emphasizing the necessity of balanced depalmitoylation.

Efficacy of dual intracerebroventricular and intravitreal CLN5 gene therapy in sheep prompts the first clinical trial to treat CLN5 Batten disease

Mutations in the CLN5 gene cause the fatal, pediatric, neurodegenerative disease CLN5 neuronal ceroid lipofuscinosis. Affected children suffer progressive neuronal loss, visual failure and premature death. Presently there is no treatment. This study evaluated dual intracerebroventricular (ICV) and intravitreal (IVT) administration of a self-complementary adeno-associated viral vector encoding ovine CLN5 (scAAV9/oCLN5) into CLN5 affected sheep (CLN5−/−) at various disease stages. CLN5 disease progression was slowed in pre-symptomatic sheep who received a moderate dose of scAAV9/oCLN5, whilst a higher ICV dose treatment in early and advanced symptomatic animals delayed or halted disease progression. Intracranial (brain) volume loss was attenuated in all treatment cohorts, and visual function was also sustained in both the early and advanced symptomatic treated sheep over the 24-month duration of the study. Robust CLN5 protein expression was detected throughout the brain and spinal cord, and improvements in central nervous system and retinal disease correlates were observed. These findings hold translational promise for extending and improving the quality of life in both pre-symptomatic and symptomatic CLN5 patients, and prompted the initiation of the first in-human Phase I/II clinical trial testing ICV/IVT administration of scAAV9 encoding human CLN5 (https://clinicaltrials.gov/; NCT05228145).

Loss of Progranulin Results in Increased Pan-Cathepsin Activity

Mutations in the progranulin (PGRN) encoding gene, GRN, cause familial frontotemporal dementia (FTD) and neuronal ceroid lipofuscinosis (NCL) and PGRN is also implicated in Parkinson’s disease (PD). These mutations result in decreased PGRN expression. PGRN is highly expressed in peripheral immune cells and microglia and regulates cell growth, survival, repair, and inflammation. As well, PGRN is implicated in regulating lysosome function, however, the exact role of PGRN in lysosomal function and how this contributes to inflammation and degeneration is not entirely understood. To better understand the role of PGRN in regulating lysosome function, this study examined how loss of GRN impacts lysosomal and cathepsin activity. Using mouse embryonic fibroblasts (MEFs), immunocytochemistry and immunoblotting assays were performed to analyze fluorescent signal from LAMP1 (lysosomal marker) and BMV109 (marker for pan-cathepsin activity). GRN-/- MEFs exhibit increased expression of pan-cathepsin activity relative to GRN+/+ MEFs, and significantly impacts expression of LAMP1. The significant increase in pan-cathepsin activity in the GRN-/- MEFs confirms that PGRN loss does alter cathepsin expression, which may be a result of compensatory mechanisms happening within the cell. Further investigations will include assessing LAMP1 and BMV109 expression in microglia from GRN-/- mice, in the hopes of understanding the role of PGRN in lysosomal function in immune cells of the central nervous system and the diseases in which it is implicated.

TPP1 Variants in Iranian patients: A Novel Pathogenic Homozygous Variant Causing Neuronal Ceroid Lipofuscinosis 2

Introduction: TPP1 variants have been identified as a causative agent of neuronal ceroid lipofuscinosis 2 disease, that ataxia is one of its clinical features. Therefore, here, molecular study of TPP1 variants is presented in an Iranian cohort and a novel pathogenic variant is described. Methods: This investigation was conducted as a cross-sectional study in a tertiary referral hospital, Children’s Medical Center, Pediatrics Center of Excellence. Clinical presentations and pedigrees were documented. Patients with cerebellar ataxia were enrolled in this study. Next-generation sequencing was applied to confirm the diagnosis. Segregation and bioinformatics analyses were also done for the variants using Sanger sequencing. Results: Forty-five patients were included in our study. The mean age of onset was 104 (+55.60) months (minimum = 31 months, maximum = 216 months). The majority of cases (73.3%) were born to consanguineous parents and only 1 patient (2.2%) had an affected sibling. Of the 45 patients, only 1 patient with a novel pathogenic variant (c.1425_1425+1delinsAT, p.A476Cfs*15) in the TPP1 gene was identified. Discussion: The main strength of current study is the relatively large sample size. Besides, a novel pathogenic variant could be important toward the diagnosis and management of this condition. With significant advances in various therapies, early diagnosis could improve the treatments using personalized-based medicine.

Neuronal ceroid lipofuscinosis: A case report

Neuronal ceroid lipofuscinoses (NCL) represent severe neurodegenerative conditions which is one of the lysosomal storage disorders. There are four main clinical forms of NCL among which late infantile variety is the second most common condition. Here, we discuss a case concerning a boy aged 5 years and 4 months who exhibited a continuous decline in cognitive and motor functions starting from the age of 4. As the disorder advanced, he experienced gradual deterioration of his eyesight, unsteady walking and myoclonic seizures. An electroencephalogram performed on the child demonstrated widespread instances of sharp and slow wave discharges alongside a slowed background activity. Magnetic resonance imaging revealed extensive cerebral and noticeable cerebellar degeneration. A skin biopsy extracted from the armpit area displayed distinctive eosinophilic inclusions within the cells and structures in the eccrine ducts which stained positively for periodic acid-Schiff. These findings indicated a possibility of neuronal ceroid lipofuscinoses. Bangabandhu Sheikh Mujib Medical University Journal 2023;16(3): 174-177

Loss of mfsd8 alters the secretome during Dictyostelium aggregation

Major facilitator superfamily domain-containing protein 8 (MFSD8) is a transmembrane protein that has been reported to function as a lysosomal chloride channel. In humans, homozygous mutations in MFSD8 cause a late-infantile form of neuronal ceroid lipofuscinosis (NCL) called CLN7 disease. In the social amoeba Dictyostelium discoideum, Mfsd8 localizes to cytoplasmic puncta and vesicles, and regulates conserved processes during the organism’s life cycle. Here, we used D. discoideum to examine the effect of mfsd8-deficiency on the secretome during the early stages of multicellular development. Mass spectrometry revealed 61 proteins that were differentially released by cells after 4 and 8 h of starvation. Most proteins were present in increased amounts in mfsd8- conditioned buffer compared to WT indicating that loss of mfsd8 deregulates protein secretion and/or causes the release of proteins not normally secreted by WT cells. GO term enrichment analyses showed that many of the proteins aberrantly released by mfsd8- cells localize to compartments and regions of the cell associated with the endo-lysosomal and secretory pathways. Mass spectrometry also revealed proteins previously known to be impacted by the loss of mfsd8 (e.g., cathepsin D), as well as proteins that may underlie mfsd8-deficiency phenotypes during aggregation. Finally, we show that mfsd8-deficiency reduces intracellular proteasome 20S activity due to the abnormal release of at least one proteasomal subunit. Together, this study reveals the impact of mfsd8 loss on the secretome during D. discoideum aggregation and lays the foundation for follow up work that investigates the role of altered protein release in CLN7 disease.

Treatment of non-epileptic episodes of anxious, fearful behavior in adolescent juvenile neuronal ceroid lipofuscinosis (CLN3 disease).

Recurrent non-epileptic episodes of frightened facial and body expression occur in more than half of post-adolescent patients with juvenile neuronal ceroid lipofuscinosis (JNCL, CLN3 disease). Clinically, the episodes look similar to the attacks of paroxysmal sympathetic hyperactivity (PSH) commonly seen following traumatic brain injury (TBI). The episodes occur when the patients are exposed to separation, hear loud sounds or are otherwise bothered by discomfort and as in PSH following TBI, the attacks are difficult to prevent and/or treat. Based on present knowledge of triggering factors, the neural anxiety/fear circuit, its afferent and efferent pathways and documented CLN3 disease-impact on these tracks, the current study discusses a rational approach how to prevent and/or treat the attacks. Patients with JNCL have a disturbed somatosensory modulation leading to a reduced threshold of pain; a degeneration within the neural anxiety/fear circuit leading to an imbalance of central network inhibition and excitation pathways; and finally, an, with advancing age, increasing autonomic imbalance leading to a significant dominance of the sympathetic neural system. Theoretically, there are three points of attack how to prevent or treat the episodes: (1) increase in threshold of discomfort impact; (2) modulation of imbalance of central network inhibition and excitation, and (3) restoring the balance between the sympathetic and parasympathetic neural systems prompted by a parasympathetic withdrawal. As to (1) and (2), prevention should have the greatest priority. As regards (3), research of transcutaneous vagal stimulation treatment in JNCL is warranted.

A Homozygous MAN2B1 Missense Mutation in a Doberman Pinscher Dog with Neurodegeneration, Cytoplasmic Vacuoles, Autofluorescent Storage Granules, and an α-Mannosidase Deficiency.

A 7-month-old Doberman Pinscher dog presented with progressive neurological signs and brain atrophy suggestive of a hereditary neurodegenerative disorder. The dog was euthanized due to the progression of disease signs. Microscopic examination of tissues collected at the time of euthanasia revealed massive accumulations of vacuolar inclusions in cells throughout the central nervous system, suggestive of a lysosomal storage disorder. A whole genome sequence generated with DNA from the affected dog contained a likely causal, homozygous missense variant in MAN2B1 that predicted an Asp104Gly amino acid substitution that was unique among whole genome sequences from over 4000 dogs. A lack of detectable α-mannosidase enzyme activity confirmed a diagnosis of a-mannosidosis. In addition to the vacuolar inclusions characteristic of α-mannosidosis, the dog exhibited accumulations of autofluorescent intracellular inclusions in some of the same tissues. The autofluorescence was similar to that which occurs in a group of lysosomal storage disorders called neuronal ceroid lipofuscinoses (NCLs). As in many of the NCLs, some of the storage bodies immunostained strongly for mitochondrial ATP synthase subunit c protein. This protein is not a substrate for α-mannosidase, so its accumulation and the development of storage body autofluorescence were likely due to a generalized impairment of lysosomal function secondary to the accumulation of α-mannosidase substrates. Thus, it appears that storage body autofluorescence and subunit c accumulation are not unique to the NCLs. Consistent with generalized lysosomal impairment, the affected dog exhibited accumulations of intracellular inclusions with varied and complex ultrastructural features characteristic of autophagolysosomes. Impaired autophagic flux may be a general feature of this class of disorders that contributes to disease pathology and could be a target for therapeutic intervention. In addition to storage body accumulation, glial activation indicative of neuroinflammation was observed in the brain and spinal cord of the proband.

An Overview of the Neurotrophic and Neuroprotective Properties of the Psychoactive Drug Lithium as an Autophagy Modulator in Neurodegenerative Conditions.

For both short-term and long-term treatment of bipolar disorder, lithium is a prototypical mood stabilizer. Lithium's neuroprotective properties were revealed by cumulative translational research, which opened the door to reforming the chemical as a treatment for neurodegenerative illnesses. The control of homeostatic systems such as oxidative stress, autophagy, apoptosis, mitochondrial function, and inflammation underlies lithium's neuroprotective characteristics. The fact that lithium inhibits the enzymes inositol monophosphatase (IMPase) and glycogen synthase kinase (GSK)-3 may be the cause of the various intracellular reactions. In this article, we review lithium's neurobiological properties, as demonstrated by its neurotrophic and neuroprotective capabilities, as well as translational studies in cells in culture and in animal models of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Prion disease, amyotrophic lateral sclerosis (ALS), ischemic stroke, and neuronal ceroid lipofuscinosis (NCL), discussing the justification for the drug's use in the treatment of these neurodegenerative disorders.

TUNEL-positive structures in activated microglia and SQSTM1/p62-positive structures in activated astrocytes in the neurodegenerative brain of a CLN10 mouse model.

Neuronal ceroid lipofuscinosis is a group of pediatric neurodegenerative diseases. One of their causative genes, CLN10/CtsD, encodes cathepsin D, a major lysosomal protease. Central nervous system (CNS)-specific CtsD-deficient mice exhibit a neurodegenerative disease phenotype with accumulation of ceroid lipofuscins, granular osmiophilic deposits, and SQSTM1/p62. We focused on activated astrocytes and microglia in this neurodegenerative mouse brain, since there are few studies on the relationship between these accumulators and lysosomes in these glial cells. Activated microglia and astrocytes in this mouse thalamus at p24 were increased by approximately 2.5- and 4.6-fold compared with the control, while neurons were decreased by approximately half. Granular osmiophilic deposits were detected in microglial cell bodies and extended their processes in the thalamus. LAMP1-positive lysosomes, but not SQSTM1/p62 aggregates, accumulated in microglia of this mouse thalamus, whereas both lysosomes and SQSTM1/p62 aggregates accumulated in its astrocytes. TUNEL-positive signals were observed mainly in microglia, but few were observed in neurons and astrocytes. These signals were fragmented DNA from degenerated neurons engulfed by microglia or in the lysosomes of microglia. Abnormal autophagic vacuoles also accumulated in the lysosomes of microglia. Granular osmiophilic deposit-like structures localized to LAMP1-positive lysosomes in CtsD-deficient astrocytes. SQSTM1/p62-positive but LAMP1-negative membranous structures also accumulated in the astrocytes and were less condensed than typical granular osmiophilic deposits. These results suggest that CtsD deficiency leads to intracellular abnormalities in activated microglia and astrocytes in addition to neuronal degeneration.

Long-term safety and dose escalation of intracerebroventricular CLN5 gene therapy in sheep supports clinical translation for CLN5 Batten disease.

CLN5 neuronal ceroid lipofuscinosis (NCL, Batten disease) is a rare, inherited fatal neurodegenerative disorder caused by mutations in the CLN5 gene. The disease is characterised by progressive neuronal loss, blindness, and premature death. There is no cure. This study evaluated the efficacy of intracerebroventricular (ICV) delivery of an adeno-associated viral vector encoding ovine CLN5 (scAAV9/oCLN5) in a naturally occurring sheep model of CLN5 disease. CLN5 affected (CLN5-/-) sheep received low, moderate, or high doses of scAAV9/oCLN5 at three disease stages. The treatment delayed disease progression, extended survival and slowed stereotypical brain atrophy in most animals. Of note, one high dose treated animal only developed mild disease symptomology and survived to 60.1 months of age, triple the natural life expectancy of an untreated CLN5-/- sheep. Eyesight was not preserved at any administration age or dosage. Histopathologic examination revealed that greater transduction efficiency was achieved through higher ICV doses, and this resulted in greater amelioration of disease pathology. Together with other pre-clinical data from CLN5-/- sheep, the safety and efficacy data from these investigational new drug (IND)-enabling studies supported the initiation of the first in-human CLN5 gene therapy clinical study using the ICV delivery route for the treatment of CLN5 NCL. Clinical Trial Registration: https://clinicaltrials.gov/, identifier NCT05228145.

Language Delay in Patients with CLN2 Disease: Could It Support Earlier Diagnosis?

Neuronal ceroid lipofuscinosis type 2 (CLN2 disease) is a rare pediatric disorder associated with rapid neurodegeneration, and premature death in adolescence. An effective enzyme replacement therapy (cerliponase alfa) has been approved that can reduce this predictable neurological decline. The nonspecific early symptoms of CLN2 disease frequently delay diagnosis and appropriate management. Seizures are generally recognized as the first presenting symptom of CLN2 disease, but emerging data show that language delay may precede this. An improved understanding of language deficits in the earliest stage of CLN2 disease may support the early identification of patients. In this article, CLN2 disease experts examine how language development is affected by CLN2 disease in their clinical practices. The authors' experiences highlighted the timings of first words and first use of sentences, and language stagnation as key features of language deficits in CLN2 disease, and how deficits in language may be an earlier sign of the disease than seizures. Potential challenges in identifying early language deficits include assessing patients with other complex needs, and recognizing that a child's language abilities are not within normal parameters given the variability of language development in young children. CLN2 disease should be considered in children presenting with language delay and/or seizures to facilitate earlier diagnosis and access to treatment that can significantly reduce morbidity.