The Abca7 variant reduces Aβ generation, plaque load, and neuronal damage.

Background: Variants in ABCA7, a member of the ABC transporter superfamily, have been associated with increased risk for developing late onset Alzheimer's disease (LOAD).

Methods: CRISPR-Cas9 was used to generate an Abca7 variant in mice, modeling the homologous human ABCA7 variant, and extensive characterization was performed.

Results: Abca7 microglia show differential gene expression profiles upon lipopolysaccharide challenge and increased phagocytic capacity.

Ablation of microglia following infection of the central nervous system with a neurotropic murine coronavirus infection leads to increased demyelination and impaired remyelination.

Intracranial inoculation of susceptible mice with a glial-tropic strain of mouse hepatitis virus (JHMV), a murine coronavirus, results in an acute encephalomyelitis followed by viral persistence in white matter tracts accompanied by chronic neuroinflammation and demyelination. Microglia are the resident immune cell of the central nervous system (CNS) and are considered important in regulating events associated with neuroinflammation as well as influencing both white matter damage and remyelination. To better understand mechanisms by which microglia contribute to these immune-mediated events, JHMV-infected mice with established demyelination were treated with the small molecular inhibitor of colony stimulating factor 1 receptor (CSF1R), PLX5622, to deplete microglia.

A Trem2 mouse model without cryptic splicing drives age- and disease-dependent tissue damage and synaptic loss in response to plaques.

Background: The TREM2 R47H variant is one of the strongest genetic risk factors for late-onset Alzheimer's Disease (AD). Unfortunately, many current Trem2 mouse models are associated with cryptic mRNA splicing of the mutant allele that produces a confounding reduction in protein product. To overcome this issue, we developed the Trem2 (Normal Splice Site) mouse model in which the Trem2 allele is expressed at a similar level to the wild-type Trem2 allele without evidence of cryptic splicing products.

SPG302 Reverses Synaptic and Cognitive Deficits Without Altering Amyloid or Tau Pathology in a Transgenic Model of Alzheimer's Disease.

Alzheimer's disease (AD) is conceptualized as a synaptic failure disorder in which loss of glutamatergic synapses is a major driver of cognitive decline. Thus, novel therapeutic strategies aimed at regenerating synapses may represent a promising approach to mitigate cognitive deficits in AD patients. At present, no disease-modifying drugs exist for AD, and approved therapies are palliative at best, lacking in the ability to reverse the synaptic failure.

Generation of a humanized Aβ expressing mouse demonstrating aspects of Alzheimer's disease-like pathology.

The majority of Alzheimer's disease (AD) cases are late-onset and occur sporadically, however most mouse models of the disease harbor pathogenic mutations, rendering them better representations of familial autosomal-dominant forms of the disease. Here, we generated knock-in mice that express wildtype human Aβ under control of the mouse App locus. Remarkably, changing 3 amino acids in the mouse Aβ sequence to its wild-type human counterpart leads to age-dependent impairments in cognition and synaptic plasticity, brain volumetric changes, inflammatory alterations, the appearance of Periodic Acid-Schiff (PAS) granules and changes in gene expression.