Autophagy in alzheimer disease pathogenesis and its therapeutic values

Alzheimer disease (AD) is the most common form of dementia with hallmarks of β-amyloid deposits, neurofilament tangles, synaptic loss and neuronal death in the patient's brain. AD is a heavy burden in an ageing society as there are no effective therapies in treating the causes or slowing down its progression. Autophagy is a conserved process through formation of double membrane structure, namely autophagosome which is delivered to lysosome to digest cellular disposals. Autophagy maintains homoeostasis in the brain and is generally considered to protect brain functions against ageing. The first evidence of autophagy involvement in AD is that there is decreased expression of autophagy essential genes in post-mortem AD brains. Autophagy is also believed to be protective in neurodegeneration. However, the molecular and cellular mechanisms for dysfunction of autophagy in AD are not fully understood. Recent studies of autophagy regulation in AD cover the findings not only in neurons, but also from fast growing evidence for their importance in glia and brain vascular system. Thus, this review composes pertinent information regarding the involvement of autophagy in neurons, glias (including microglia, astrocyte, and oligodendrocyte), and brain vascular cells in AD, and their unique cellular mechanisms of this connection in AD pathology. We will provide effectual insights both in investigating autophagy in AD pathological mechanisms and in establishing a strategic approach for developing autophagy-based AD therapies.