scholarly journals A second X chromosome contributes to resilience in a mouse model of Alzheimer’s disease

2020 ◽  
Vol 12 (558) ◽  
pp. eaaz5677 ◽  
Author(s):  
Emily J. Davis ◽  
Lauren Broestl ◽  
Samira Abdulai-Saiku ◽  
Kurtresha Worden ◽  
Luke W. Bonham ◽  
...  

A major sex difference in Alzheimer’s disease (AD) is that men with the disease die earlier than do women. In aging and preclinical AD, men also show more cognitive deficits. Here, we show that the X chromosome affects AD-related vulnerability in mice expressing the human amyloid precursor protein (hAPP), a model of AD. XY-hAPP mice genetically modified to develop testicles or ovaries showed worse mortality and deficits than did XX-hAPP mice with either gonad, indicating a sex chromosome effect. To dissect whether the absence of a second X chromosome or the presence of a Y chromosome conferred a disadvantage on male mice, we varied sex chromosome dosage. With or without a Y chromosome, hAPP mice with one X chromosome showed worse mortality and deficits than did those with two X chromosomes. Thus, adding a second X chromosome conferred resilience to XY males and XO females. In addition, the Y chromosome, its sex-determining region Y gene (Sry), or testicular development modified mortality in hAPP mice with one X chromosome such that XY males with testicles survived longer than did XY or XO females with ovaries. Furthermore, a second X chromosome conferred resilience potentially through the candidate gene Kdm6a, which does not undergo X-linked inactivation. In humans, genetic variation in KDM6A was linked to higher brain expression and associated with less cognitive decline in aging and preclinical AD, suggesting its relevance to human brain health. Our study suggests a potential role for sex chromosomes in modulating disease vulnerability related to AD.

2011 ◽  
Vol 46 (3) ◽  
pp. 606-615 ◽  
Author(s):  
Enrica Boda ◽  
Eriola Hoxha ◽  
Alessandro Pini ◽  
Francesca Montarolo ◽  
Filippo Tempia

2021 ◽  
Author(s):  
Carolina Soares ◽  
Débora G. Souza ◽  
Andreia Silva da Rocha ◽  
Luiza Machado ◽  
Bruna Bellaver ◽  
...  

Background: Transgenic models of Alzheimer’s disease (AD) overexpress human APP, PS1 or PS2 mutations. These models present amyloid-beta pathology but do not recapitulate the complexity of AD. Interestingly, the transgenic rat model TgF344-AD, which overpresses human APP and PS1 mutations, seems to follow a more similar disease progression, manifesting progressive tau tangle-like pathology and late cognitive impairment. Yet, whether they develop energy metabolism changes as we see in AD remains unclear. Objective: Here, we investigated brain bioenergetics in 6-7 months F344-AD/WT rats, an age where animals present early amyloid pathology but no memory impairment - mimicking the human preclinical AD. Methods: We used high-resolution respirometry to assess mitochondrial oxidative phosphorylation capacity (OXPHOS), electron transfer capacity (ET), respiratory control ratio (RCR) and reserve capacity (R) in brain homogenates of male and female F344-AD and WT rats (n = 6-8, per group). Results: The results were analyzed by Welch’s t test: 1. Frontal cortex a)OXPHOS (p=0.307); b)ET (p=0.99); c)RCR (p=0.138); d)R (p=0.482). 2. Hippocampus a)OXPHOS (p=0.446); b)ET (p=0.409); c)RCR (p=0.952); d)R (p=0.503). Conclusion: In conclusion, at 6-7 months, changes in the respirometry in the brain of F344-AD rats were not observed. We hypothesize that these measures will be altered at older ages.


2021 ◽  
Vol 28 (2) ◽  
pp. 307-319
Author(s):  
Jimiece Thomas ◽  
Haddon Smith ◽  
C. Aaron Smith ◽  
Lori Coward ◽  
Gregory Gorman ◽  
...  

The use of angiotensin-converting enzyme inhibitors (ACEis) has been reported to reduce symptoms of cognitive decline in patients with Alzheimer’s disease (AD). Yet, the protective role of ACEis against AD symptoms is still controversial. Here, we aimed at determining whether oral treatment with the ACEi lisinopril has beneficial effects on cognitive and physical functions in a Drosophila melanogaster model of AD that overexpresses the human amyloid precursor protein and the human β-site APP-cleaving enzyme in neurons. We found a significant impairment in learning and memory as well as in climbing ability in young AD flies compared to control flies. After evaluation of the kynurenine pathway of tryptophan metabolism, we also found that AD flies displayed a >30-fold increase in the levels of the neurotoxic 3-hydroxykynurenine (3-HK) in their heads. Furthermore, compared to control flies, AD flies had significantly higher levels of the reactive oxygen species (ROS) hydrogen peroxide in their muscle-enriched thoraces. Lisinopril significantly improved deficits in learning and memory and climbing ability in AD flies. The positive impact of lisinopril on physical function might be, in part, explained by a significant reduction in ROS levels in the thoraces of the lisinopril-fed AD flies. However, lisinopril did not affect the levels of 3-HK. In conclusion, our findings provide novel and relevant insights into the therapeutic potential of ACEis in a preclinical AD model.


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