Tau in Alzheimer's Disease: Pathological Alterations and an Attractive Therapeutic Target.

Alzheimer's disease (AD) is an age-related neurodegenerative disease with two major hallmarks: extracellular amyloid plaques made of amyloid-ß (Aß) and intracellular neurofibrillary tangles (NFTs) of abnormally hyperphosphorylated tau. The number of NFTs correlates positively with the severity of dementia in AD patients. However, there is still no efficient therapy available for AD treatment and prevention so far. A deeper understanding of AD pathogenesis has identified novel strategies for the generation of specific therapies over the past few decades. Several studies have suggested that the prion-like seeding and spreading of tau pathology in the brain may be a key driver of AD. Tau protein is considered as a promising candidate target for the development of therapeutic interventions due to its considerable pathological role in a variety of neurodegenerative disorders. Abnormal tau hyperphosphorylation plays a detrimental pathological role, eventually leading to neurodegeneration. In the present review, we describe the recent research progresses in the pathological mechanisms of tau protein in AD and briefly discuss tau-based therapeutic strategies.

[Expression of HIF-1alpha induced by ginkgolides in primary cultured cortical neurons and the relationship with ERK signal pathway].

AIM: To study the effects of ginkgolides (Gin) on the expression of hypoxia-inducible factor-1alpha (H1F-1alpha) in primary cultured cortical neurons treated with CoCl2 and the relationship with ERK signal pathway. METHODS: We observed the effects of Gin (37.5 mg/L) on morphology and viability on primary cultured cortical neurons with treatment of CoCl2 (125 micromol/L). The expression of HIF-1alpha and p-ERK of neurons induced by CoCl2 pretreated with Gin were assessed by Western-blot. We analyzed the relationship between HIF-1alpha expression activated by Gin and ERK signal pathway with treatment of PD98059 (100 micromol/L), a selective inhibitor of ERK. RESULTS: It was shown that Gin had protective effects on CoCl2 damaged neurons by raising the neuronal viability. Some basic expression of HIF-1alpha and p-ERK were observed in normal cultured cortical neurons. The expression of HIF-1alpha and p-ERK increased strikingly when treated with CoCl2 for 4 h. The levels of HIF-1alpha and p-ERK increased even more in the neurons pretreated with Gin for 24 h before CoCl2. The levels of HIF-1alpha and p-ERK were notably inhibited with pretreatment of PD98059, while Gin could prevent this inhibition. CONCLUSION: Gin has protective effects on neurons damaged by CoCl2 which might be related to the increase of the level of HIF-1alpha and the activation of ERK signal pathway.