Treatment of lysosomal storage disorders: focus on the neuronal ceroid-lipofuscinoses

Recent advances in our understanding of lysosomal storage disorders (LSDs) may lead to new therapies to treat the neuronal ceroid-lipofuscinoses (NCLs). In this review, enzyme replacement therapy, gene therapy, cell-mediated therapy and pharmaceutical treatments are considered across the LSDs and extended to therapies for the NCLs. It is likely that a combination of approaches will produce the most beneficial clinical outcome for treatment of pathologies displayed by the NCLs.     

Cortical neuronal and glial pathology in TgTauP301L transgenic mice: neuronal degeneration, memory disturbance, and phenotypic variation

Recapitulation of tau pathologies in an animal model has been a long-standing goal in neurodegenerative disease research. We generated transgenic (TgTauP301L) mice expressing a frontotemporal dementia with parkinsonism linked to chromosome 17 (FTPD-17) mutation within the longest form of tau (2N, 4R). TgTauP301L mice developed florid pathology including neuronal pretangles, numerous Gallyas-Braak-positive neurofibrillary tangles, and glial fibrillary tangles in the frontotemporal areas of the cerebrum, in the brainstem, and to a lesser extent in the spinal cord. These features were accompanied by gliosis, neuronal loss, and cerebral atrophy. Accumulated tau was hyperphosphorylated, conformationally changed, ubiquitinated, and sarkosyl-insoluble, with electron microscopy demonstrating wavy filaments. Aged TgTauP301L mice exhibited impairment in hippocampally dependent and independent behavioral paradigms, with impairments closely related to the presence of tau pathologies and levels of insoluble tau protein. We conclude that TgTauP301L mice recreate the substantial phenotypic variation and spectrum of pathologies seen in FTDP-17 patients. Identification of genetic and/or environmental factors modifying the tau phenotype in these mice may shed light on factors modulating human tauopathies. These transgenic mice may aid therapeutic development for FTDP-17 and other diseases featuring accumulations of four-repeat tau, such as Alzheimer's disease, corticobasal degeneration, and progressive supranuclear palsy.     

Neurology of the neuronal ceroid-lipofuscinoses: Late infantile and juvenile types

My experience with more than 80 cases of the late infantile and juvenile forms of the neuronal ceroid-lipofuscinoses over the last 5 years has led to the following realizations. The 2 variants are neurologically distinct entities and probably are the result of different genetic defects. Treatment includes supportive measures and anticonvulsant medication. Therapy for behavioral and psychiatric disturbances in the juvenile type proves to be particularly challenging as neuroleptic medications tend to worsen parkinsonian like symptoms. Neuropathologic and neuro radiologic explanation of clinical symptomatology correlates best with neuronal loss and not neuronal storage. There is a paucity of neuropathologic documentation of these 2 types; additional reports are encouraged.     

Classification of the neuronal ceroid-lipofuscinoses: Expansion of the atypical forms

The neuronal ceroid-lipofuscinoses (NCL) are a group of different genetic diseases. The major types of NCL are expressed by six forms which represent different clinicopathologic and genetic forms. These are CLN-1, Infantile; CLN-2, Late Infantile; CLN-3, Juvenile; CLN-4, Adult-Recessive; CLN-5, Adult-Dominant; and CLN-6, Early Juvenile. The distinction between CLN-4 and CLN-5 is still disputatious. CLN-6 has been called CLN-5. A seventh classification of NCL represents from 12 to 20% of those afflicted. This group consists of an extensive array of atypical types of ceroid-lipofuscin accumulation in the secondary lysosomes of neurons and cells of other tissues (e.g., skin, conjunctiva, and lymphocytes) or by presumed clinical and genetic relationships. The authors have identified 15 atypical subtypes of NCL. These as a group are here described as a seventh form. Further biochemical, molecular, and genetic studies will identify more precisely the phenotypic and genotypic expression of these “minor” forms of NCL. © 1995 Wiley-Liss, Inc.     

Neurology of the neuronal ceroid-lipofuscinoses: late infantile and juvenile types.

My experience with more than 80 cases of the late infantile and juvenile forms of the neuronal ceroid-lipofuscinoses over the last 5 years has led to the following realizations. The 2 variants are neurologically distinct entities and probably are the result of different genetic defects. Treatment includes supportive measures and anticonvulsant medication. Therapy for behavioral and psychiatric disturbances in the juvenile type proves to be particularly challenging as neuroleptic medications tend to worsen parkinsonian like symptoms. Neuropathologic and neuroradiologic explanation of clinical symptomatology correlates best with neuronal loss and not neuronal storage. There is a paucity of neuropathologic documentation of these 2 types; additional reports are encouraged.     

Aminopyridazines inhibit beta-amyloid-induced glial activation and neuronal damage in vivo

The critical role of chronic inflammation in disease progression continues to be increasingly appreciated across multiple disease areas, especially in neurodegenerative disorders such as Alzheimer’s disease. We report that late intervention with a recently discovered aminopyridazine suppressor of glial activation, developed to inhibit both oxidative and inflammatory cytokine pathways, attenuates human amyloid beta (Aβ)-induced glial activation in a murine model. Peripheral administration of the aminopyridazine MW01-070C, beginning 3 weeks after the start of intracerebroventricular infusion of human Aβ1-42, decreased the number of activated astrocytes and microglia and the levels of proinflammatory cytokines interleukin-1β, tumor necrosis factor- and S100B in the hippocampus. Inhibition of neuroinflammation correlated with a decreased neuron loss, restoration towards control levels of synaptic dysfunction biomarkers in the hippocampus, and diminished amyloid plaque deposition. The results from this in vivo chemical biology approach provide a proof of concept that targeting of key glia inflammatory cytokine pathways can suppress Aβ-induced neuroinflammation in vivo, with resultant attenuation of neuronal damage.     

Comparative biology of the neuronal ceroid-lipofuscinoses (NCL): An overview

Multiple forms of ceroid-lipofuscinosis occur in human beings and animals. They are characterized by brain and retinal atrophy associated with selective necrosis of neurons. This neurodegenerative disease appears associated with the disease process rather than storage of fluorescent lipopigment per se, and there is now growing evidence that pathogenesis may involve mitochondria rather than a primary defect of lysosomal catabolism. Of the forms of ceroid-lipofuscinosis studied, most but not all reflect accumulation of subunit c of mitochondrial ATP synthase. If there is a common denominator between all forms other than the presence of fluorescent lipopigment, then it may be the accumulation of hydrophobic protein. Analogous diseases in animals can be expected to reflect the same spectrum of biochemical changes, and they warrant in-deptb study to help understand the pathogenesis and heterogeneity of the group. © 1995 Wiley-Liss, Inc.     

Participation of autophagy in storage of lysosomes in neurons from mouse models of neuronal ceroid-lipofuscinoses (Batten disease)

In cathepsin D-deficient (CD-/-) and cathepsins B and L double-deficient (CB-/-CL-/-) mice, abnormal vacuolar structures accumulate in neurons of the brains. Many of these structures resemble autophagosomes in which part of the cytoplasm is retained but their precise nature and biogenesis remain unknown. We show here how autophagy contributes to the accumulation of these vacuolar structures in neurons deficient in cathepsin D or both cathepsins B and L by demonstrating an increased conversion of the molecular form of MAP1-LC3 for autophagosome formation from the cytosolic form (LC3-I) to the membrane-bound form (LC3-II). In both CD-/- and CB-/-CL-/- mouse brains, the membrane-bound LC3-II form predominated whereas MAP1-LC3 signals accumulated in granular structures located in neuronal perikarya and axons of these mutant brains and were localized to the membranes of autophagosomes, evidenced by immunofluorescence microscopy and freeze-fracture-replica immunoelectron microscopy. Moreover, as in CD-/- neurons, autofluorescence and subunit c of mitochondrial ATP synthase accumulated in CB-/-CL-/- neurons. This suggests that not only CD-/- but also CB-/-CL-/- mice could be useful animal models for neuronal ceroid-lipofuscinosis/Batten disease. These data strongly argue for a major involvement of autophagy in the pathogenesis of Batten disease/lysosomal storage disorders.     

Cell type-specific markers for human glial and neuronal cells in culture

We have used cell type-specific markers to identify and study the major classes of neural cells in dissociated cell cultures of optic nerve, spinal cord, and dorsal root ganglion from 15- to 21-week-old human fetuses. Astrocytes were identified by the intracellular expression of glial fibrillary acidic protein, oligodendrocytes by the cell surface expression of galactocerebroside, dorsal root ganglion neurons by their ability to bind tetanus toxin at their surface, and macrophages (including microglia) by cell surface Fc receptors and their phagocytic properties. Oligodendrocytes continued to express galactocerebroside (and some of them, also myelin basic protein) for up to 1 week in culture in the absence of neurons. While some dorsal root ganglion Schwann cells initially expressed galactocerebroside on their surface, and myelin basic protein and the major peripheral myelin glycoprotein (PO) intracellularly, they no longer expressed detectable amounts of any of these myelin-specific molecules after several days in culture. The Thy-1-like glycoprotein was found on the surface of fibroblasts, dorsal root ganglion neurons, and some astrocytes but not oligodendrocytes or the majority of leptomeningeal cells. Fibronectin was only expressed by fibroblasts and leptomeningeal cells.     

Ultrastructural pathology of neuronal membranes in the oedematous human cerebral cortex

Surgical biopsies of frontal, parietal and temporal regions of thirty two patients with clinical diagnosis of congenital hydrocephalus, brain trauma, tumours, and vascular anomalies were examined with the transmission electron microscope. The main goal was to study the submicroscopic alterations of somatodendritic, axonal, and synaptic plasma membranes, cytomembranes, and the cytoskeleton. In both, moderate and severe oedema, fragmentation of plasma membrane, enlargement and focal necrosis of rough endoplasmic cisterns and nuclear envelope, detachment of membrane-bound ribosomes and reduction of polysome were observed. The degenerated myelinated axons exhibited discontinuities of the axolemma, disorganisation of multiple myelin lamellae, myelin sheath vacuolization, and formation of myelin ovoids. In severe oedema, synaptic disassembly was frequently found characterized by separate pre- and postsynaptic endings and loss of perisynaptic glial ensheathment. Fragmented and intact microtubules and actin-like filaments also were distinguished. The alterations of plasma membranes and cytomembranes are related with the anoxic-ischaemic conditions of brain parenchyma. The role of free radical and lipid peroxidation, disturbed energy metabolism, altered metabolic cascades, excitotoxicity, protein aggregation, and presence of extracellular oedema fluid is discussed in relation with the derangement of neuronal membranes.     

Involvement of the skin in late infantile and juvenile amaurotic idiocies (neuronal ceroid-lipofuscinoses)

Skin biopsies have been performed in five cases belonging to the group of neuronal ceroid-lipofuscinoses (two cases of late infantile amaurotic idiocy with curvilinear cytosomes and three cases of juvenile amaurotic idiocy) and in twelve controls. In the late infantile amaurotic idiocy, cytosomes with curvilinear profiles were easily discovered in the epithelial cells and in the various skin appendages. A clinical diagnosis can therefore be readily supported by an innocuous and repeatable procedure. In juvenile amaurotic idiocy, pleiomorphic cytosomes with prevalent curvilinear profiles can be found in the skin appendages; they are smaller, less abundant and a more careful search is necessary to discover them.     

Activation of microglial NADPH oxidase is synergistic with glial iNOS expression in inducing neuronal death: a dual-key mechanism of inflammatory neurodegeneration

Background  

Inflammation-activated glia are seen in many CNS pathologies and may kill neurons through the release of cytotoxic mediators, such as nitric oxide from inducible NO synthase (iNOS), and possibly superoxide from NADPH oxidase (NOX). We set out to determine the relative role of these species in inducing neuronal death, and to test the dual-key hypothesis that the production of both species simultaneously is required for significant neuronal death.     

Immunocytochemistry of neuronal and glial markers in retinoblastoma

Summary An immunocytochemical study of 30 retinoblastomas was carried out using antibodies to neuronal and glial markers. The tumours were found to react with antibodies to neuron-specific enolase (NSE), a marker for neuronal elements, and S-100 and glial fibrillary acidic protein (GFAP), both of which are proteins present in glia. Two distinct cell populations were found within the tumour: the first, composed of anaplastic tumour cells at various stages of differentiation, showed both NSE and S-100 immunoreactivity; the second cell type, which immunostained for S-100 and GFAP, resembled mature glial cells. The results of this study indicate that the retinoblastoma may arise from a pluripotential primitive cell partially retaining neuronal and glial characteristics.     

Phosphorylation of tau at THR212 and SER214 in human neuronal and glial cultures: the role of AKT

We have reported recently that the microtubule-associated protein tau is phosphorylated in vitro by Akt, an important kinase in anti-apoptotic signaling regulated by insulin and growth factors. We also established that Akt phosphorylates tau separately at T212 and S214, two sites previously shown to be phosphorylated by glycogen synthase kinase 3beta (GSK3beta) and protein kinase A (PKA), respectively. In the present studies, we examined the relationship between Akt and T212/S214 in primary cultures of human neurons and astrocytes, and evaluated the contribution of two other kinases. In intact cells, we found a very low content of active (phospho-S473) form of Akt. We also found a low content of phospho-S214 but not phospho-T212 of tau, suggesting that only phospho-S212 may depend on Akt activity in situ. We upregulated Akt activity using two experimental models: treatment with a protein phosphatase inhibitor, okadaic acid, and transfection with a constitutively active Akt gene construct (c-Akt). Under these conditions, phosphorylation of tau at T212 and S214 was regulated independently, with little change or downregulation of phospho-T212 and dynamic upregulation of phospho-S214. Our studies revealed that Akt may influence the phospho-S214 content in a meaningful manner. They also revealed that PKA may only partially contribute to the phosphorylation of S214. In comparison, okadaic acid treatment severely depleted the content of GSK3beta and downregulated the remaining GSK3beta activity by Akt-dependent inhibition, consistent with minimal changes in phospho-T212. In summary, these results strongly suggest that in primary cultures, Akt selectively phosphorylates tau at S214 rather than T212. Our studies raise the possibility that tau S214 may participate in Akt-mediated anti-apoptotic signaling.     

Incidence of neuronal ceroid-lipofuscinoses in West Germany: Variation of a method for studying autosomal recessive disorders

The incidence of neuronal ceroid-lipofuscinoses (NCL) in West Germany was determined using a novel method which is applicable to other autosomal recessively inherited diseases. Questionnaires were sent to all pediatric departments (answer rate 189/276, 68%), schools for the blind (39/46, 85%), and neuropathological institutes (15/22,68%). Diagnoses were accepted only when based on firm clinical and/or electron microscopic criteria; 207 such identified patients were sorted according to year of birth. Plotting the cumulative number of new cases per year against the year of birth resulted in a slightly S-shaped curve. Before the year 1962, the curve is relatively flat, probably due to inefficient case registration. Between 1968 and 1977, the slope of the curve is constant–a steep, nearly straight line. Thereafter the curve flattens out again, likely due to inefficient registration of young, still undiagnosed patients. We interpret the central segment of the curve, which is continuously straight over a period of 10 years and corresponds to 92 patients, as a period in which efficient registration of new cases occurred. The number of live births being 7,211,543 during the same period, the NCL incidence is calculated to be 1.28 per 100,000 live births (0.71 for juvenile NCL and 0.46 for late infantile NCL).     

Detection and properties of benzodiazepine receptors of glial and neuronal fractions of the human cerebral cortex

Bulletin of Experimental Biology and Medicine -     

Cutaneous breast cancer deposits show distinct growth patterns with different degrees of angiogenesis,hypoxia and fibrin deposition

AIMS: We postulated that skin metastases and cutaneous local recurrences from breast adenocarcinoma show different growth patterns with distinct angiogenic profiles. METHODS AND RESULTS: Fifty-one surgically resected dermal breast cancer deposits were evaluated for growth pattern, E-cadherin expression, presence of necrosis and a fibrotic focus, fibrin deposition, carbonic anhydrase IX expression (CA IX), microvessel density, endothelial cell proliferation and blood vessel immaturity. Growth patterns were infiltrative, with carcinoma cells infiltrating the dermis without significant disturbance of the pre-existing architecture, expansive, meaning that a nodule of carcinoma cells and desmoplastic tissue pushed aside the pre-existing dermal structures, or mixed. All lobular carcinomas showed an infiltrative growth and lacked membranous E-cadherin expression. Different growth patterns in the ductal carcinomas were not correlated with differences in E-cadherin expression. The presence of necrosis and/or a fibrotic focus and the expression of the hypoxia marker CA IX were significantly associated with an expansive growth. Fibrin was present in all expansive deposits and less frequently in the other growth patterns. There was a positive association between fibrin deposition, CA IX expression and microvessel density. The latter was significantly higher in the expansive and mixed growth patterns than in the infiltrative pattern. Endothelial cell proliferation was highest in the expansive growth pattern and was positively correlated with the presence of a fibrotic focus and with fibrin deposition. The maximum percentage of immature blood vessels was higher in the expansive and mixed growth patterns than in the infiltrative one. CONCLUSION: The recognition of different subgroups of cutaneous breast cancer deposits with different degrees of hypoxia-driven angiogenesis may have important implications for the usefulness of anti-angiogenic therapy.     

Effects of adherence, activation and distinct serum proteins on the in vitro human monocyte maturation process

Elutriator-purified human monocytes were cultured in a serum-free (SF) medium, and various serum proteins and functional activating agents were assessed for their effects on the in vitro maturation of human monocytes to macrophages. Following 3 days of suspension culture in Teflon labware, 60% of the monocytes were easily recovered. When varying concentrations of human AB serum (HuAB) were employed, human monocyte maturation progressed rapidly; the kinetics of this maturation process during cell suspension culture were very similar to the pattern observed following adherence culture. In contrast, when SF medium was employed, a marked retardation of the monocyte maturation process was observed; this could not be attributed to any changes in cell recovery and/or viability. Thus, cells could be maintained in their monocytoid form for 3 days when cultured in SF medium. When HuAB was added after 3 days of culture, human monocyte maturation into macrophages proceeded at a normal rate. We attempted to characterize certain of the serum protein(s) found in HuAB which promoted the monocyte maturation process. Human immunoglobulin G (IgG) was found to be the most potent serum protein in increasing 5'-N activity and decreasing peroxidase activity of suspension cultured monocytes. Immunoglobulin M (IgM) and albumin (Alb) were shown not to have significant monocyte maturation activity. Heat-treated human gamma globulin and IgG purified by high-performance liquid chromatography (HPLC) were shown to have patterns identical with that of untreated HGG and IgG with regard to promoting monocyte maturation; F(ab')2 was not an active maturation promoter, indicating the need for an intact Fc portion of the IgG molecule. Fibrinogen and fibronectin also had maturation promoting activity. Finally, addition of the potent monocyte functional activators, muramyl dipeptide (MDP), polyriboinosinic:polyribocytidilic acid (Poly I:C), and lipopolysaccharide (LPS) had no effect on the monocyte maturation process. Thus, neither cell adherence or activation appear to be critical for the monocyte to macrophage maturation process. Instead, we hypothesize that in addition to proper nutritional support, a group of serum proteins (unified mainly by their ability to interact with monocyte membrane receptors) appear to be the principal promoters of this process.