PrP turnover in vivo and the time to effect of prion disease therapeutics.

PrP lowering is effective against prion disease in animal models and is being tested clinically. Therapies in the current pipeline lower PrP production, leaving pre-existing PrP to be cleared according to its own half-life. We hypothesized that PrP's half-life may be a rate-limiting factor for the time to effect of PrP-lowering drugs, and one reason why late treatment of prion-infected mice is not as effective as early treatment.

Alpha-synuclein null mutation exacerbates the phenotype of a model of Menkes disease in female mice.

Genetic modifier screens provide a useful tool, in diverse organisms from to and mice, for recovering new genes of interest that may reduce or enhance a phenotype of interest. This study reports a modifier screen, based on N-ethyl-N-nitrosourea (ENU) mutagenesis and outcrossing, designed to increase understanding of the normal function of murine α-synuclein (). Human was the first gene linked to familial Parkinson's disease.

Therapeutic Trial of anle138b in Mouse Models of Genetic Prion Disease.

Phenotypic screening has yielded small-molecule inhibitors of prion replication that are effective against certain prion strains but not others. Here, we sought to test the small molecule anle138b in multiple mouse models of prion disease. In mice inoculated with the RML strain of prions, anle138b doubled survival and durably suppressed astrogliosis measured by live-animal bioluminescence imaging.

Parkinson's Disease: Overview of Transcription Factor Regulation, Genetics, and Cellular and Animal Models.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, affecting nearly 7-10 million people worldwide. Over the last decade, there has been considerable progress in our understanding of the genetic basis of PD, in the development of stem cell-based and animal models of PD, and in management of some clinical features. However, there remains little ability to change the trajectory of PD and limited knowledge of the underlying etiology of PD.

Regional variability and genotypic and pharmacodynamic effects on PrP concentration in the CNS.

Prion protein (PrP) concentration controls the kinetics of prion replication and is a genetically and pharmacologically validated therapeutic target for prion disease. In order to evaluate PrP concentration as a pharmacodynamic biomarker and assess its contribution to known prion disease risk factors, we developed and validated a plate-based immunoassay reactive for PrP across 6 species of interest and applicable to brain and cerebrospinal fluid (CSF). PrP concentration varied dramatically across different brain regions in mice, cynomolgus macaques, and humans.

Prion protein lowering is a disease-modifying therapy across prion disease stages, strains and endpoints.

Lowering of prion protein (PrP) expression in the brain is a genetically validated therapeutic hypothesis in prion disease. We recently showed that antisense oligonucleotide (ASO)-mediated PrP suppression extends survival and delays disease onset in intracerebrally prion-infected mice in both prophylactic and delayed dosing paradigms. Here, we examine the efficacy of this therapeutic approach across diverse paradigms, varying the dose and dosing regimen, prion strain, treatment timepoint, and examining symptomatic, survival, and biomarker readouts.

Antisense oligonucleotides extend survival of prion-infected mice.

Prion disease is a fatal, incurable neurodegenerative disease of humans and other mammals caused by conversion of cellular prion protein (PrP; PrPC) into a self-propagating neurotoxic conformer (prions; PrPSc). Strong genetic proofs of concept support lowering PrP expression as a therapeutic strategy. Antisense oligonucleotides (ASOs) can provide a practical route to lowering one target mRNA in the brain, but their development for prion disease has been hindered by three unresolved questions from prior work: uncertainty about mechanism of action, unclear potential for efficacy against established prion infection, and poor tolerability of drug delivery by osmotic pumps.

Cerebrospinal fluid-based kinetic biomarkers of axonal transport in monitoring neurodegeneration.

Progress in neurodegenerative disease research is hampered by the lack of biomarkers of neuronal dysfunction. We here identified a class of cerebrospinal fluid-based (CSF-based) kinetic biomarkers that reflect altered neuronal transport of protein cargo, a common feature of neurodegeneration. After a pulse administration of heavy water (2H2O), distinct, newly synthesized 2H-labeled neuronal proteins were transported to nerve terminals and secreted, and then appeared in CSF.

Introduction of large insert DNA into mammalian cells and embryos.

This unit provides a set of protocols for introducing large insert DNA into cultured mammalian cells and embryos. Two different methods, spheroplast fusion and lipofection, are described for effecting transfer of YACs or gel-purified YAC DNA into cells. Additional protocols discuss preparing and transferring BACs into cells by lipofection and into embryos by microinjection.

Exacerbated synucleinopathy in mice expressing A53T SNCA on a Snca null background.

Alpha-Synuclein is a major component of Lewy bodies, neuronal inclusions diagnostic for Parkinson's disease (PD). While an Ala53Thr mutation in alpha-synuclein can cause PD in humans, in mice the wildtype residue at position 53 is threonine, indicating that mice are either too short-lived to develop PD, or are protected by the six other amino acid differences between the proteins in these two species. Mice carrying an Ala53Thr human SNCA transgene driven by the mouse prion promoter show a mild movement disorder and only rarely develop severe pathology by 2 years of age.

Synaptic vesicle depletion correlates with attenuated synaptic responses to prolonged repetitive stimulation in mice lacking alpha-synuclein.

Although the mutation of alpha-synuclein, a protein associated with presynaptic vesicles, is implicated in the etiology and pathogenesis of Parkinson's disease, the biological function of the normal protein is unknown. Mice that lack alpha-synuclein have been generated by homologous recombination in embryonic stem cells. Electron microscopic examination of hippocampal synapses revealed a striking selective deficiency of undocked vesicles without affecting docked vesicles.

Use of comparative physical and sequence mapping to annotate mouse chromosome 16 and human chromosome 21.

Distal mouse chromosome 16 (MMU16) shares conserved linkage with human chromosome 21 (HSA21), trisomy for which causes Down syndrome (DS). A 4.5-Mb physical map extending from Cbr1 to Tmprss2 on MMU16 provides a minimal tiling path of P1 artificial chromosomes (PACs) for comparative mapping and genomic sequencing.

Human and mouse alpha-synuclein genes: comparative genomic sequence analysis and identification of a novel gene regulatory element.

The human alpha-synuclein gene (SNCA) encodes a presynaptic nerve terminal protein that was originally identified as a precursor of the non-beta-amyloid component of Alzheimer's disease plaques. More recently, mutations in SNCA have been identified in some cases of familial Parkinson's disease, presenting numerous new areas of investigation for this important disease. Molecular studies would benefit from detailed information about the long-range sequence context of SNCA.

Physical and comparative mapping of distal mouse chromosome 16. 5 p5.

Distal mouse Chromosome 16 (Chr. 16) includes a region of conserved linkage with human Chromosome 21 (Chr. 21).

Localization of tumor suppressor activity important in nonsmall cell lung carcinoma on chromosome 11q.

Loss of heterozygosity on chromosome 11q23 is observed at high frequency in human nonsmall cell lung carcinomas (NSCLCs), suggesting the presence of a tumor suppressor gene. Previous analysis of DNA from 79 patients identified a commonly deleted segment of 5 centimorgans. Complementation analysis was used to further localize a putative tumor suppressor gene.

High-resolution recombinational map of mouse chromosome 16.

Five intersubspecific backcrosses and an intercross were used to establish a sex-averaged recombinational map spanning 56 cM across most of mouse Chromosome 16 (Chr 16). A total of 123 markers were ordered using an interval mapping approach to identify 425 recombination sites in a collection of 1154 meioses from 1155 progeny generated in the six crosses. The markers include the 10 "classic" Chr 16 reference markers, 26 additional genes or transcripts including two phenotypic markers (Pit1dw and Kcnj6wv), and 87 simple sequence length polymorphisms (SSLPs).

Molecular genetic characterization and comparative mapping of the human PCP4 gene.

The mouse Pcp4 gene is highly expressed in brain, primarily in cerebellar Purkinje cells. It maps to chromosome 16 (Chr 16), in a region of conserved synteny with human chromosome 21 (Chr 21). To further characterize PCP4 and its possible contribution to cerebellar hypoplasia in trisomy 21, or Down Syndrome (DS), we cloned and sequenced the full length human cDNA, isolated a YAC which carries the entire gene, determined the gene structure, and characterized its expression.

Assessment of a mutation in the H5 domain of Girk2 as a candidate for the weaver mutation.

A mutation in the GIRK2 inwardly rectifying K+ channel was mapped recently to the region of mouse chromosome 16 containing the wv gene and shown to occur in mutant but not in wild-type mice. We demonstrate tight linkage of the Girk2 mutation to the wv phenotype and refine the localization of the weaver (wv) gene on recombinational and physical maps. This linkage between Girk2 and wv has existed since at least 1988 in descendants of the original mutation maintained in C57BL/6 animals.