A lysosomal enigma CLN5 and its significance in understanding neuronal ceroid lipofuscinosis

Neuronal Ceroid Lipofuscinosis (NCL), also known as Batten disease, is an incurable childhood brain disease. The thirteen forms of NCL are caused by mutations in thirteen CLN genes. Mutations in one CLN gene, CLN5, cause variant late-infantile NCL, with an age of onset between 4 and 7 years. The CLN5 protein is ubiquitously expressed in the majority of tissues studied and in the brain, CLN5 shows both neuronal and glial cell expression. Mutations in CLN5 are associated with the accumulation of autofluorescent storage material in lysosomes, the recycling units of the cell, in the brain and peripheral tissues. CLN5 resides in the lysosome and its function is still elusive. Initial studies suggested CLN5 was a transmembrane protein, which was later revealed to be processed into a soluble form. Multiple glycosylation sites have been reported, which may dictate its localisation and function. CLN5 interacts with several CLN proteins, and other lysosomal proteins, making it an important candidate to understand lysosomal biology. The existing knowledge on CLN5 biology stems from studies using several model organisms, including mice, sheep, cattle, dogs, social amoeba and cell cultures. Each model organism has its advantages and limitations, making it crucial to adopt a combinatorial approach, using both human cells and model organisms, to understand CLN5 pathologies and design drug therapies. In this comprehensive review, we have summarised and critiqued existing literature on CLN5 and have discussed the missing pieces of the puzzle that need to be addressed to develop an efficient therapy for CLN5 Batten disease

Lentiviral vectors as tools to understand central nervous system biology in mammalian model organisms

Lentiviruses have been extensively used as gene delivery vectors since the mid-1990s. Usually derived from the human immunodeficiency virus genome, they mediate efficient gene transfer to non-dividing cells, including neurons and glia in the adult mammalian brain. In addition, integration of the recombinant lentiviral construct into the host genome provides permanent expression, including the progeny of dividing neural precursors. In this review, we describe targeted vectors with modified envelope glycoproteins and expression of transgenes under the regulation of cell-selective and inducible promoters. This technology has broad utility to address fundamental questions in neuroscience and we outline how this has been used in rodents and primates. Combining viral tract tracing with immunohistochemistry and confocal or electron microscopy, lentiviral vectors provide a tool to selectively label and trace specific neuronal populations at gross or ultrastructural levels. Additionally, new generation optogenetic technologies can be readily utilized to analyze neuronal circuit and gene functions in the mature mammalian brain. Examples of these applications, limitations of current systems and prospects for future developments to enhance neuroscience knowledge will be reviewed. Finally, we will discuss how these vectors may be translated from gene therapy trials into the clinical setting

Beitraege zur Intercalationschemie von Graphit und turbostratischen Kohlenstoffen

SIGLEAvailable from TIB Hannover: DW 4665 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Modification of activated carbon hydrophobicity by pyrolysis of propene

The chemical nature of the surface of a granular activated carbon has been modified by heat treatment under nitrogen at 1000 °C followed by pyrolysis of propene in the 300–600 °C temperature range. Cracking of propene produces deposits of coke on the more reactive sites of the carbon surface, those produced after the decomposition of the original oxygen surface groups along the previous heat treatment. The process leads to an initial reduction in the number of oxygen surface groups and in the capacity of the carbon to chemisorb oxygen. The further growth of the carbon deposit in the interior of the particle decreases the width of the micropore entrance, which is paralleled by the coating of the external surface of the particle. The reduction in the number of active sites of the carbon leads to a decrease in the enthalpy of immersion into polar liquids such as water and ethylenediamine, the carbon becoming more hydrophobic than the original.Support from the EU (Contract FRESP ECGA no. 218138)

Effect of Soluble Amyloid Precursor Protein-alpha on Adult Hippocampal Neurogenesis in a Mouse Model of Alzheimer’s Disease

Abstract Soluble amyloid precursor protein-alpha (sAPPα) is a regulator of neuronal and memory mechanisms, while also having neurogenic and neuroprotective effects in the brain. As adult hippocampal neurogenesis is impaired in Alzheimer’s disease, we tested the hypothesis that sAPPα delivery would rescue adult hippocampal neurogenesis in an APP/PS1 mouse model of Alzheimer’s disease. An adeno-associated virus-9 (AAV9) encoding murine sAPPα was injected into the hippocampus of 8 month-old wild-type and APP/PS1 mice, and later two different thymidine analogues (XdU) were systemically injected to label adult-born cells at different time points after viral transduction. The proliferation of adult-born cells, cell survival after eight weeks, and cell differentiation into either neurons or astrocytes was studied. Proliferation was impaired in APP/PS1 mice but was restored to wild-type levels by viral expression of sAPPα. In contrast, sAPPα overexpression failed to rescue the survival of XdU+-labelled cells that was impaired in APP/PS1 mice, although it did cause a significant increase in the area density of astrocytes in the granule cell layer across both genotypes. Finally, viral expression of sAPPα reduced amyloid-beta plaque load in APP/PS1 mice in the dentate gyrus and somatosensory cortex. These data add further evidence that increased levels of sAPPα could be therapeutic for the cognitive decline in AD, in part through restoration of the proliferation of neural progenitor cells in adults.</jats:p

Effective gene therapy in CLN5 Ovine Batten disease

Lambs homozygous for a mutation causing CLN5 Batten disease (neuronal ceroid lipofuscinosis, NCL) injected with viral vectors containing the corrective gene showed no signs of disease development a year later, whereas uninjected affected animals declined considerably. AAV9 and lentiviral derived vectors expressing green fluorescent protein showed widespread expression 30 days after direct injection into the lateral ventricles or parenchyma of sheep with no ill effects. Injection of vectors loaded with the corrective ovine CLN5 sequence into preclinical affected lambs at 2-4 months was followed by monitoring over the next 12 months. In all three tests performed monthly, neurological and eyesight tests, monitoring of their ability to join cohorts by navigating through a maze and estimates of cranial cavity volumes in vivo from CT scans, the injected sheep were indistinguishable from the unaffected controls. Over this time the non-injected affected controls declined markedly and developed obvious clinical symptoms, to the point of being unable to navigate the maze. Monitoring of the injected sheep continues. Similar injections into CLN6 affected sheep were not nearly as effective, only 1/6 showing a difference from non-injected affected controls.This research was funded by grants from Cure Kids New Zealand, the Batten Disease Support and Research Association (BDSRA), Batten Disease New Zealand and the American New Zealand Association

The “window of susceptibility” for inflammation in the immature central nervous system is characterized by a leaky blood–brain barrier and the local expression of inflammatory chemokines

Early in postnatal development, the immature central nervous system (CNS) is more susceptible to inflammation than its adult counterpart. We show here that this “window of susceptibility” is characterized by the presence of leaky vessels in the CNS, and by a global chemokine expression profile which is clearly distinct from the one observed in the adult CNS and has three important characteristics. First, it contains chemokines with known roles in the differentiation and maturation of glia and neurons. Secondly, these chemokines have been described before in inflammatory lesions of the CNS, where they are important for the recruitment of monocytes and T cells. And last, the chemokine profile is shaped by pathological changes like oligodendrocyte stress and attempts of myelin repair. Changes in the chemokine expression profile along with a leaky blood brain barrier pave the ground for an accelerated development of CNS inflammation