Neuropathological and behavioral characterization of aged Grn R493X progranulin-deficient frontotemporal dementia knockin mice

Frontotemporal lobar degeneration (FTLD) causes a spectrum of clinical presentations of frontotemporal dementia (FTD), including progressive changes in behavior, personality, executive function, and language. Up to 20% of familial FTLD cases are caused by progranulin (GRN) haploinsufficiency (FTD-GRN), with one of the most common causal variant being a nonsense mutation at arginine 493 (R493X). Recently, a genetic knockin FTD-GRN mouse model was generated bearing this Grn(R493X) mutation, at the analogous arginine in murine Grn. Aged, homozygous Grn(R493X) mice (Grn(R493X/R493X)) have been shown to phenotypically replicate several neuropathological hallmarks previously demonstrated in Grn null mice. We conducted a comprehensive neuropathological and behavioral assessment of 18 month old Grn(R493X/R493X) mice, observing a striking lysosomal dysfunction and thalamic neurodegeneration not previously described in this model, as well as a male-specific increase in generalized anxiety. These findings provide additional phenotypic markers of pathogenesis in aged Grn(R493X/R493X) mice that will contribute to better defining mechanisms underlying FTD-GRN, and offer relevant outcome measures for preclinical efficacy testing of novel therapeutics that target nonsense mutations leading to this devastating disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40478-021-01158-x.