Object recognition as a measure of memory in 1-2 years old transgenic minipigs carrying the APPsw mutation for Alzheimer's disease.

Alzheimer's disease (AD) is a disabling, fatal disease, where animal models potentially can enable investigation of aetiology and treatment. The first litter of Göttingen minipigs carrying a mutation for human AD was born in 2007, showing transgene expression. In human AD patients, memory impairment is the most striking and consistent feature. The aim of the present study was to examine effects of the APPsw transgene on memory of AD minipigs compared with non-transgenic controls at two ages (1-2 years) using the spontaneous object recognition test (SORT), which is based on behavioural discrimination of familiar and novel objects. No significant difference between AD minipigs and controls was found when comparing object recognition as a measure of memory. The minipigs did explore the novel object significantly more than the familiar, indicating the expected recognition of the familiar object. Two different inter-phase intervals were used (IPI: 10-40 min). For both ages, object recognition was evident using 10 min IPI. When using 40 min IPI, object recognition was evident only at age 1 year. Comparing memory of a relatively small group of AD minipigs and controls at two rather young ages using the SORT, we were not able to show memory impairment in APPsw carrying minipigs. Being an age-dependent disease, the transgene is expected to cause AD-like symptoms in this porcine model, and the SORT should be repeated at older ages.

Spatio-temporal regulation of ADAR editing during development in porcine neural tissues.

Editing by ADAR enzymes is essential for mammalian life. Still, knowledge of the spatio-temporal editing patterns in mammals is limited. By use of 454 amplicon sequencing we examined the editing status of 12 regionally extracted mRNAs from porcine developing brain encompassing a total of 64 putative ADAR editing sites. In total 24 brain tissues, dissected from up to five regions from embryonic gestation day 23, 42, 60, 80, 100 and 115, were examined for editing.   Generally, editing increased during embryonic development concomitantly with an increase in ADAR2 mRNA level. Notably, the Gria2 (GluR-B) Q/R site, reported to be ~100% edited in previous studies, is only 54% edited at embryonic day 23. Transcripts with multiple editing sites in close proximity to each other exhibit coupled editing and an extraordinary incidence of long-range coupling of editing events more than 32 kb apart is observed for the kainate glutamate receptor 2 transcript, Grik2. Our study reveals complex spatio-temporal ADAR editing patterns of coordinated editing events that may play important roles in the development of the mammalian brain.

Inhaled nebulized glatiramer acetate against Gram-negative bacteria is not associated with adverse pulmonary reactions in healthy, young adult female pigs.

The developmental speed of new antimicrobials does not meet the emergence of multidrug-resistant bacteria sufficiently. A potential shortcut is assessing the antimicrobial activity of already approved drugs. Intrudingly, the antibacterial action of glatiramer acetate (GA) has recently been discovered. GA is a well-known and safe immunomodulatory drug particular effective against Gram-negative bacteria, which disrupts biological membranes by resembling the activity of antimicrobial peptides. Thus, GA can potentially be included in treatment strategies used to combat infections caused by multidrug-resistant Gram-negatives. One potential application is chronic respiratory infections caused by Pseudomonas aeruginosa, however the safety of GA inhalation has never been assessed. Here, the safety of inhaling nebulized GA is evaluated in a preclinical pig model. The potential side effects, i.e., bronchoconstriction, respiratory tract symptoms and systemic- and local inflammation were assessed by ventilator monitoring, clinical observation, biochemistry, flowcytometry, and histopathology. No signs of bronchoconstriction assessed by increased airway peak pressure, Ppeak, or decreased oxygen pressure were observed. Also, there were no signs of local inflammation in the final histopathology examination of the pulmonary tissue. As we did not observe any potential pulmonary side effects of inhaled GA, our preliminary results suggest that GA inhalation is safe and potentially can be a part of the treatment strategy targeting chronic lung infections caused by multidrug-resistant Gram-negative bacteria.

A reassessment of the neuropathology of frontotemporal dementia linked to chromosome 3.

A large Danish family has previously been reported in which autosomal dominant frontotemporal dementia (FTD) is genetically linked to chromosome 3 (FTD-3). A mutation was recently identified in the CHMP2B gene that is probably responsible for causing disease in this family. Because of its neuropathologic findings, FTD-3 was originally categorized as a subtype of frontotemporal lobar degeneration, termed "dementia lacking distinctive histopathology." We now report a reevaluation of the neuropathologic changes in this family. Postmortem material from 4 affected family members was available for examination. Gross examination revealed generalized cortical atrophy that was most severe in frontal and temporal cortices. Microscopy showed loss of cortical neurons, microvacuolation of layer II, mild gliosis, and demyelination of the deep white matter. Results of immunohistochemical staining for alpha-synuclein, prion protein, neurofilament, and tau protein were unremarkable. Variable numbers of small, round, ubiquitin-positive cytoplasmic inclusions were present in the dentate granule layer of the hippocampus in all 4 cases. Rare ubiquitin-positive inclusions were also found in frontal and temporal cortical neurons. These inclusions were also positive for p62 but not for TDP-43. The finding of ubiquitin- and p62-positive, TDP-43-negative cytoplasmic inclusions in the hippocampus and neocortex suggests reclassification of the neuropathology of FTD-3 as a unique subtype of frontotemporal lobar degeneration with ubiquitin-positive inclusions that are TDP-43-negative.

Characterization and expression analysis in the developing embryonic brain of the porcine FET family: FUS, EWS, and TAF15.

The FET protein family consists of FUS (TLS), EWS (EWSR1), and TAF15. The FET proteins bind DNA and RNA and are involved in transcriptional regulation and RNA processing. Translocations involving the FET genes have been identified in human sarcomas, and mutations in the FUS and TAF15 genes are associated with Amyotrophic Lateral Sclerosis. We here describe the characterization of the porcine FET proteins and an expression analysis during embryonic brain development. The FET proteins are well conserved between pig and human. FET protein mutations associated with Amyotrophic Lateral Sclerosis affect evolutionary conserved amino acids. In cultured cells the porcine FET proteins have a nuclear localization with some specific cytoplasmic aggregation of TAF15 in neuronal progenitor cells. Immunohistochemical analyses supported a predominant nuclear localization, but also faint cytoplasmic localization. The FET proteins have similar expression profiles throughout the development of the embryonic porcine brain and most cell types appeared positive for expression. Quantitative RT-PCR analyses showed that the FET mRNA expression decreased during embryonic development of hippocampus and for FUS and EWS during embryonic development of cortex. FET mRNA expression was relatively constant in brain stem, basal ganglia, and cerebellum. Overall the FET protein localization and mRNA and protein expression analyses were concordant with previous analysis from the human brain. The presented results indicate that the porcine brain could be an alternative model for the future examination of the normal functions as well as neurological disease associated functions of the FET proteins.

Protein replacement therapy partially corrects the cholesterol-storage phenotype in a mouse model of Niemann-Pick type C2 disease.

Niemann-Pick type C2 (NPC2) disease is a fatal autosomal recessive neurovisceral degenerative disorder characterized by late endosomal-lysosomal sequestration of low-density lipoprotein derived cholesterol. The breach in intracellular cholesterol homeostasis is caused by deficiency of functional NPC2, a soluble sterol binding protein targeted to the lysosomes by binding the mannose-6-phosphate receptor. As currently there is no effective treatment for the disorder, we have investigated the efficacy of NPC2 replacement therapy in a murine gene-trap model of NPC2-disease generated on the 129P2/OlaHsd genetic background. NPC2 was purified from bovine milk and its functional competence assured in NPC2-deficient fibroblasts using the specific cholesterol fluorescent probe filipin. For evaluation of phenotype correction in vivo, three-week-old NPC2(-/-) mice received two weekly intravenous injections of 5 mg/kg NPC2 until trial termination 66 days later. Whereas the saline treated NPC2(-/-) mice exhibited massive visceral cholesterol storage as compared to their wild-type littermates, administration of NPC2 caused a marked reduction in cholesterol build up. The histological findings, indicating an amelioration of the disease pathology in liver, spleen, and lungs, corroborated the biochemical results. Little or no difference in the overall cholesterol levels was observed in the kidneys, blood, cerebral cortex and hippocampus when comparing NPC2(-/-) and wild type mice. However, cerebellum cholesterol was increased about two fold in NPC2(-/-) mice compared with wild-type littermates. Weight gain performance was slightly improved as a result of the NPC2 treatment but significant motor coordination deficits were still observed. Accordingly, ultrastructural cerebellar abnormalities were detected in both saline treated and NPC2 treated NPC2(-/-) animals 87 days post partum. Our data indicate that protein replacement may be a beneficial therapeutic approach in the treatment of the visceral manifestations in NPC2 disease and further suggest that neurodegeneration is not secondary to visceral dysfunction.

[Rare form of Creutzfeldt-Jakob disease]. / Sjaelden form for Creutzfeldt-Jakobs sygdom.

Creutzfeldt-Jakob disease (CJD) is the most common type of prion disease. A considerable variation in disease phenotype is seen, primarily influenced by a naturally occurring polymorphism in the prion protein gene. We present a case of sporadic CJD of atactic type. Molecular genetic analysis showed a VV polymorphism at codon 129 in the prion protein gene. The various polymorphisms at codon 129 and their influence on the clinical picture and pathology are briefly discussed.

Aromatic l-amino acid decarboxylase expression profiling and isoform detection in the developing porcine brain.

Aromatic l-amino acid decarboxylase (AADC) enzymatic activity is essential for the biosynthesis of the serotonin and dopamine neurotransmitters, and AADC activity is functionally associated with a number of human neuronal disorders. Here we describe the molecular characterization of AADC from the pig. Pig AADC shows a high degree of similarity to human and rodent AADC at the cDNA and protein level. Exon position shuffling has exchanged the location of the stop codon in pig AADC to the last exon 15 instead for the exon 14 position in the human, the rat, and the mouse AADC. Several pig AADC isoforms were identified, including the also in human described extraneuronal and neuronal isoforms generated by alternative splicing and alternative promoter usage. The AADC expression in the developing pig brain is highly expressed in the basal ganglia and the brain stem regions, and also significantly expressed in the cortex, the hippocampus and the cerebellum. Moreover, we observe that both the neuronal and the extraneuronal AADC mRNA isoforms were present at early brain developmental stages in the brain stem and the basal ganglia. This presents the first evidence that the non-neuronal AADC isoform also is expressed in the brain. Together our results propose that the porcine model is useful for future functional delineations of the AADC gene at the molecular level.

Specific recognition of the C-terminal end of A beta 42 by a high affinity monoclonal antibody.

The neurotoxic peptide A beta(42) is derived from the amyloid precursor protein by proteolytic cleavage and is deposited in the brain of patients suffering from Alzheimer's disease (AD). In this study we generate a high affinity monoclonal antibody that targets the C-terminal end of A beta(42) with high specificity. By this is meant that the paratope of the antibody must enclose the C-terminal end of A beta(42) including the carboxy-group of amino acid 42, and not just recognize a linear epitope in the C-terminal part of A beta. This has been accomplished by using a unique antigen construct made by the Ligand Presenting Assembly technology (LPA technology). This strategy results in dimeric presentation of the free C-terminal end of A beta(42). The generated Mab A beta1.1 is indeed specific for the C-terminal end of A beta(42) to which it binds with high affinity. Mab A beta1.1 recognizes the epitope in human AD tissue and stains plaques with high specificity. Therefore the monoclonal antibody can thus be useful in the histological investigations of the AD pathology.

Identification and characterization of GFAPkappa, a novel glial fibrillary acidic protein isoform.

Glial fibrillary acidic protein (GFAP) is the principal component of the intermediary filaments in mature astrocytes of the central nervous system (CNS). The protein consists of three domains: the head, the coiled-coil, and the tail. Here, we describe the isolation of an evolutionary conserved novel GFAP isoform, GFAPkappa, produced by alternative splicing and polyadenylation of the 3'-region of the human GFAP pre-mRNA. As a consequence, the resulting human GFAPkappa protein harbors a nonconserved C-terminal tail sequence distinct from the tails of GFAPalpha, the predominant GFAP isoform, and GFAPepsilon, an isoform which also results from alternative splicing. The head and coiled-coil rod domains are identical between the three GFAP isoforms. Interestingly, GFAPkappa is incapable of forming homomeric filaments, and increasing GFAPkappa expression levels causes a collapse of intermediate filaments formed by GFAPalpha. In searching for a biological relevance of GFAPkappa, we noticed that mRNA expression levels of GFAPalpha, GFAPepsilon, and GFAPkappa are gradually increased during development of the embryonic pig brain. However, whereas the GFAPalpha/GFAPepsilon ratio is constant, the GFAPkappa/GFAPepsilon ratio decreases during brain development. Furthermore, in glioblastoma tumors, an increased GFAPkappa/GFAPepsilon ratio is detected. Our results suggest that the relative expression level of the GFAPkappa isoform could modulate the properties of GFAP intermediate filaments and perhaps thereby influencing the motility of GFAP positive astrocytes and progenitor cells within the CNS.