[Frontiers in Bioscience S4, 1402-1412, June 1, 2012]

Manipulation of microglial activity as a therapy for Alzheimer's disease

Bobby Tan1, Rachel Huiyi Choi1, Tammy Jing Yee Chin1, Charanjit Kaur1, Eng-Ang Ling1

1Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 11759

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Amyloid cascade hypothesis
4. Tau hypothesis
5. Microglia as a mediator in Alzheimer's Disease
5.1. Role of microglia in amyloid cascade hypothesis
5.1.1. Microglial production of cytokines
5.1.2. Microglial phagocytosis
5.1.3. Factors affecting microglial activity
5.2. Role of microglia in tau hypothesis
6. Therapeutic strategies involving microglia
7. Conclusion
8. Acknowledgement
9. References

1. ABSTRACT

The review aims to elucidate the potential of microglia as a therapeutic target in alleviating Alzheimer's Disease (AD). Microglia are the resident immune cells in the brain which respond to the presence of the hallmarks of AD, amyloid-beta (A beta) plaques and neurofibrillary tangles (NFT). Activated microglia are able to phagocytose and secrete pro-inflammatory and anti-inflammatory cytokines. However, the eventual accumulation of excess A beta peptides and NFT in AD means that microglial clearance of pathogens has been impaired. Pro-inflammatory cytokines may also contribute to the neurodegeneration. Based on the amyloid cascade hypothesis, A beta-activated microglia can produce pro-inflammatory cytokines which may exacerbate the hyperphosporylation of tau proteins that forms NFT in AD pathology. Microglial activation can thus be manipulated to prevent neurodegeneration and promote neuroprotection through several therapeutic agents and methods. Further studies regarding comprehensive microglial response towards A beta and NFT are required to develop an effective treatment of AD involving microglia.