- Browse by Author
Browsing by Author "Karlo, J. Colleen"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Pharmacological Inhibition of ERK Signaling Rescues Pathophysiology and Behavioral Phenotype Associated with 16p11.2 Chromosomal Deletion in Mice(Society for Neuroscience, 2018-07-25) Pucilowska, Joanna; Vithayathil, Joseph; Pagani, Marco; Kelly, Caitlin; Karlo, J. Colleen; Robol, Camilla; Morella, Ilaria; Gozzi, Alessandro; Brambilla, Riccardo; Landreth, Gary E.; Anatomy and Cell Biology, School of MedicineThe human 16p11.2 microdeletion is one of the most common gene copy number variations linked to autism, but the pathophysiology associated with this chromosomal abnormality is largely unknown. The 593 kb deletion contains the ERK1 gene and other genes that converge onto the ERK/MAP kinase pathway. Perturbations in ERK signaling are linked to a group of related neurodevelopmental disorders hallmarked by intellectual disability, including autism. We report that mice harboring the 16p11.2 deletion exhibit a paradoxical elevation of ERK activity, cortical cytoarchitecture abnormalities and behavioral deficits. Importantly, we show that treatment with a novel ERK pathway inhibitor during a critical period of brain development rescues the molecular, anatomical and behavioral deficits in the 16p11.2 deletion mice. The ERK inhibitor treatment administered to adult mice ameliorates a subset of these behavioral deficits. Our findings provide evidence for potential targeted therapeutic intervention in 16p11.2 deletion carriers. SIGNIFICANCE STATEMENT The ERK/MAPK pathway is genetically linked to autism spectrum disorders and other syndromes typified by intellectual disability. We provide direct evidence connecting the ERK/MAP kinases to the developmental abnormalities in neurogenesis and cortical cytoarchitecture associated with the 16p11.2 chromosomal deletion. Most importantly, we demonstrate that treatment with a novel ERK-specific inhibitor during development rescues aberrant cortical cytoarchitecture and restores normal levels of cell-cycle regulators during cortical neurogenesis. These treatments partially reverse the behavioral deficits observed in the 16p11.2del mouse model, including hyperactivity, memory as well as olfaction, and maternal behavior. We also report a rescue of a subset of these deficits upon treatment of adult 16p11.2del mice. These data provide a strong rationale for therapeutic approaches to this disorder.Item The Trem2 R47H variant confers loss-of-function-like phenotypes in Alzheimer's disease(BMC, 2018-06-01) Cheng-Hathaway, Paul J.; Reed-Geaghan, Erin G.; Jay, Taylor R.; Casali, Brad T.; Bemiller, Shane M.; Puntambekar, Shweta S.; von Saucken, Victoria E.; Williams, Roxanne Y.; Karlo, J. Colleen; Moutinho, Miguel; Xu, Guixiang; Ransohoff, Richard M.; Lamb, Bruce T.; Landreth, Gary E.; Anatomy and Cell Biology, School of MedicineBACKGROUND: The R47H variant of Triggering Receptor Expressed on Myeloid cells 2 (TREM2) confers greatly increased risk for Alzheimer's disease (AD), reflective of a central role for myeloid cells in neurodegeneration. Understanding how this variant confers AD risk promises to provide important insights into how myeloid cells contribute to AD pathogenesis and progression. METHODS: In order to investigate this mechanism, CRISPR/Cas9 was used to generate a mouse model of AD harboring one copy of the single nucleotide polymorphism (SNP) encoding the R47H variant in murine Trem2. TREM2 expression, myeloid cell responses to amyloid deposition, plaque burden, and neuritic dystrophy were assessed at 4 months of age. RESULTS: AD mice heterozygous for the Trem2 R47H allele exhibited reduced total Trem2 mRNA expression, reduced TREM2 expression around plaques, and reduced association of myeloid cells with plaques. These results were comparable to AD mice lacking one copy of Trem2. AD mice heterozygous for the Trem2 R47H allele also showed reduced myeloid cell responses to amyloid deposition, including a reduction in proliferation and a reduction in CD45 expression around plaques. Expression of the Trem2 R47H variant also reduced dense core plaque number but increased plaque-associated neuritic dystrophy. CONCLUSIONS: These data suggest that the AD-associated TREM2 R47H variant increases risk for AD by conferring a loss of TREM2 function and enhancing neuritic dystrophy around plaques.