Analysis of CX3CR1 haplodeficiency in male and female APPswe/PSEN1dE9 mice along Alzheimer disease progression

International audienceMicroglia, the resident immune cells of the brain, have recently emerged as key players in Alzheimer Disease (AD) pathogenesis, but their roles in AD remain largely elusive and require further investigation. Microglia functions are readily altered when isolated from their brain environment, and microglia reporter mice thus represent valuable tools to study the contribution of these cells to neurodegenerative diseases such as AD. The CX3CR1+/eGFP mice is one of the most popular microglia reporter mice, and has been used in numerous studies to investigate in vivo microglial functions, including in the context of AD research. However, until now, the impact of CX3CR1 haplodeficiency on the typical features of Alzheimer Disease has not been studied in depth. To fill this gap, we generated APPswe/PSEN1dE9:CX3CR1+/eGFP mice and analyzed these mice for Alzheimer's like pathology and neuroinflammation hallmarks. More specifically, using robust multifactorial statistical and multivariate analyses, we investigated the impact of CX3CR1 deficiency in both males and females, at three typical stages of the pathology progression: at early stage when Amyloid-β (Aβ) deposition just starts, at intermediate stage during Aβ accumulation phase and at more advanced stages when Aβ plaque number stabilizes. We found that CX3CR1 haplodeficiency had little impact on the progression of the pathology in the APPswe/PSEN1dE9 model and demonstrated that the APPswe/PSEN1dE9:CX3CR1+/eGFP line is a relevant and useful model to study the role of microglia in Alzheimer Disease. In addition, although Aβ plaques density is higher in females compared to age-matched males, we show that their glial reaction, inflammation status and memory deficits are not different

Movement disorders in patients with alternating hemiplegia: "Soft" and "stiff" at the same time

International audienceAIM: To assess non-paroxysmal movement disorders in ATP1A3 mutation-positive patients with alternating hemiplegia of childhood (AHC).METHODS: Twenty-eight patients underwent neurological examination with particular focus on movement phenomenology by a specialist in movement disorders. Video recordings were reviewed by another movement disorders specialist and data were correlated to patients’ characteristics.RESULTS: Ten patients were diagnosed with chorea, 16 with dystonia (nonparoxysmal), 4 with myoclonus, and 2 with ataxia. Nine patients had more than one movement disorder and 8 patients had none. The degree of movement disorder was moderate to severe in 12/28 patients. At inclusion, dystonic patients (n=16) were older (p=0.007) than nondystonic patients. Moreover, patients (n=18) with dystonia or chorea, or both, had earlier disease onset (p=0.042) and more severe neurological impairment (p=0.012), but this did not correlate with genotype. All patients presented with hypotonia, which was characterized as moderate or severe in 16/28. Patients with dystonia or chorea (n=18) had more pronounced hypotonia (p=0.011). Bradykinesia (n=16) was associated with an early age at assessment (p<0.01). Significant dysarthria was diagnosed in 11/25 cases. A history of acute neurological deterioration and further regression of motor function, typically after a stressful event, was reported in 7 patients.INTERPRETATION: Despite the relatively limited number of patients and the cross-sectional nature of the study, this detailed categorisation of movement disorders in patients with AHC offers valuable insight into their precise characterization. Further longitudinal studies on this topic are needed