Highlights d Ab induces metabolic reprogramming of microglia from OXPHOS to glycolysis d Metabolic reprogramming of microglia is dependent on the mTOR-HIF-1a pathway d Chronic exposure to Ab induces metabolic defects of microglia d Metabolic boosting with IFN-g restores immunological function of microglia

Mitochondrial oxidative stress is a key pathologic factor in neurodegenerative diseases, including Alzheimer's disease. Abnormal generation of reactive oxygen species (ROS), resulting from mitochondrial dysfunction, can lead to neuronal cell death. Ceria (CeO2) nanoparticles are known to function as strong and recyclable ROS scavengers by shuttling between Ce(3+) and Ce(4+) oxidation states. Consequently, targeting ceria nanoparticles selectively to mitochondria might be a promising therapeutic approach for neurodegenerative diseases. Here, we report the design and synthesis of triphenylphosphonium-conjugated ceria nanoparticles that localize to mitochondria and suppress neuronal death in a 5XFAD transgenic Alzheimer's disease mouse model. The triphenylphosphonium-conjugated ceria nanoparticles mitigate reactive gliosis and morphological mitochondria damage observed in these mice. Altogether, our data indicate that the triphenylphosphonium-conjugated ceria nanoparticles are a potential therapeutic candidate for mitochondrial oxidative stress in Alzheimer's disease.

Some neurons (delay cells) in the prefrontal cortex elevate their activities throughout the time period during which the animal is required to remember past events and prepare future behavior, suggesting that working memory is mediated by continuous neural activity. It is unknown, however, how working memory is represented within a population of prefrontal cortical neurons. We recorded from neuronal ensembles in the prefrontal cortex as rats learned a new delayed alternation task. Ensemble activities changed in parallel with behavioral learning so that they increasingly allowed correct decoding of previous and future goal choices. In well-trained rats, considerable decoding was possible based on only a few neurons and after removing continuously active delay cells. These results show that neural activity in the prefrontal cortex changes dynamically during new task learning so that working memory is robustly represented and that working memory can be mediated by sequential activation of different neural populations.

ObjectiveCerebral amyloidosis and severe tauopathy in the brain are key pathological features of Alzheimer’s disease (AD). Despite a strong influence of the intestinal microbiota on AD, the causal relationship between the gut microbiota and AD pathophysiology is still elusive.DesignUsing a recently developed AD-like pathology with amyloid and neurofibrillary tangles (ADLPAPT) transgenic mouse model of AD, which shows amyloid plaques, neurofibrillary tangles and reactive gliosis in their brains along with memory deficits, we examined the impact of the gut microbiota on AD pathogenesis.ResultsComposition of the gut microbiota in ADLPAPT mice differed from that of healthy wild-type (WT) mice. Besides, ADLPAPT mice showed a loss of epithelial barrier integrity and chronic intestinal and systemic inflammation. Both frequent transfer and transplantation of the faecal microbiota from WT mice into ADLPAPT mice ameliorated the formation of amyloid β plaques and neurofibrillary tangles, glial reactivity and cognitive impairment. Additionally, the faecal microbiota transfer reversed abnormalities in the colonic expression of genes related to intestinal macrophage activity and the circulating blood inflammatory monocytes in the ADLPAPT recipient mice.ConclusionThese results indicate that microbiota-mediated intestinal and systemic immune aberrations contribute to the pathogenesis of AD in ADLPAPT mice, providing new insights into the relationship between the gut (colonic gene expression, gut permeability), blood (blood immune cell population) and brain (pathology) axis and AD (memory deficits). Thus, restoring gut microbial homeostasis may have beneficial effects on AD treatment.

SUMMARY Resistin is a cytokine that induces low-grade inflammation by stimulating monocytes in human. Resistin-mediated chronic inflammation can lead to obesity, atherosclerosis and other cardiometabolic disease. Nevertheless, the receptor for human resistin has not yet been clarified. Here, we identified adenylyl cyclase-associated protein 1(CAP1) as a functional receptor for human resistin and clarified its intracellular signaling pathway to modulate inflammatory action of monocytes. We found that human resistin directly binds to CAP1 in monocytes and up-regulates intracellular cAMP concentration, PKA activity and NF-kB-related transcription of inflammatory cytokines. Over-expression of CAP1 in monocytes enhanced resistin-induced increased activity of cAMP-dependent signaling pathway. Moreover, CAP1-over-expressed monocytes aggravated adipose tissue inflammation in transgenic mice that express human resistin from their monocytes. In contrast, suppression of CAP1 expression abrogated the resistin-mediated inflammatory activity both in vitro and in vivo. Our results highlight CAP1 as the bona fide receptor for resistin leading to inflammation in human.