Impairments in neuronal intracellular calcium (i Ca 2+) handling may contribute to Alzheimer's disease (AD) development. Metabolic dysfunction and progressive neuronal loss are associated with AD progression, and mitochondrial calcium (m Ca 2+) signaling is a key regulator of both of these processes. Here, we report remodeling of the m Ca 2+ exchange machinery in the prefrontal cortex of individuals with AD. In the 3xTg-AD mouse model impaired m Ca 2+ efflux capacity precedes neuropathology. Neuronal deletion of the mitochondrial Na + /Ca 2+ exchanger (NCLX, Slc8b1 gene) accelerated memory decline and increased amyloidosis and tau pathology. Further, genetic rescue of neuronal NCLX in 3xTg-AD mice is sufficient to impede AD-associated pathology and memory loss. We show that m Ca 2+ overload contributes to AD progression by promoting superoxide generation, metabolic dysfunction and neuronal cell death. These results provide a link between the calcium dysregulation and metabolic dysfunction hypotheses of AD and suggest m Ca 2+ exchange as potential therapeutic target in AD.

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Clinical investigations have highlighted a biological link between reduced brain glucose metabolism and Alzheimer's disease (AD). Previous studies showed that glucose deprivation may influence amyloid beta formation in vivo but no data are available on the effect that this condition might have on tau protein metabolism. In the current paper, we investigated the effect of glucose deficit on tau phosphorylation, memory and learning, and synaptic function in a transgenic mouse model of tauopathy, the h-tau mice. Compared with controls, h-tau mice with brain glucose deficit showed significant memory impairments, reduction of synaptic long-term potentiation, increased tau phosphorylation, which was mediated by the activation of P38 MAPK Kinase pathway. We believe our studies demonstrate for the first time that reduced glucose availability in the central nervous system directly triggers behavioral deficits by promoting the development of tau neuropathology and synaptic dysfunction. Since restoring brain glucose levels and metabolism could afford the opportunity to positively influence the entire AD phenotype, this approach should be considered as a novel and viable therapy for preventing and/or halting the disease progression.

The enzyme 5-lipoxygenase (5LO) is up-regulated in Alzheimer’s disease (AD), and its pharmacological blockade with zileuton slows down the development of the AD-like phenotype in young AD mice. However, its efficacy after the AD pathology is established is unknown. To this end, starting at 12-months of age triple transgenic mice (3xTg) received zileuton, a selective 5LO inhibitor, or placebo for 3 months, and then the effect of this treatment on behavior, amyloid and tau pathology assessed. While mice on placebo showed worsening of their memory, treated mice performed even better than at baseline. Compared with placebo, treated mice had significant less Aβ deposits and tau phosphorylation secondary to reduced γ-secretase and CDK-5 activation, respectively. Our data provide novel insights into the disease-modifying action of pharmacologically inhibiting 5LO as a viable AD therapeutic approach. They represent the successful completion of preclinical studies for the development of this class of drug as clinically applicable therapy for the disease.

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder. Although rare genetically linked cases of PD have been reported, most incidences are sporadic in nature. Late-onset, sporadic PD is thought to result from the combined effects of genetic and environmental risk factors exposure. Sleep and circadian rhythm disorders are recurrent among PD patients and appear early in the disease. Although some evidence supports a relationship between circadian disruption (CD) and PD, whether this is secondary to the motor symptoms or, indeed, is a factor that contributes to the pathogenesis of the disease remains to be investigated. In the present paper, we studied the direct consequence of chronic CD on the development of the phenotype in the MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridinen) model of PD. Pre-exposure to CD to mice treated with MPTP resulted in an exacerbation of motor deficit and a significant reduction in the capability of acquiring motor skills. These changes were associated with a greater loss of tyrosine hydroxylase cell content and intense neuroinflammation. Taken together, our findings demonstrate that CD by triggering a robust neuroinflammatory reaction and degeneration of the nigral-dopaminergic neuronal system exacerbates motor deficit. They support the novel hypothesis that circadian rhythm disorder is an environmental risk factor for developing PD.