Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. School of Biological Sciences, Nanyang Technological University, Singapore. Institute for Ageing Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, UK. Wolfson Centre for Age-related Diseases, King's College London, London, UK. Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Memory, Aging and Cognition Centre, National University Health System, Singapore. Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Memory, Aging and Cognition Centre, National University Health System, Singapore. Electronic address: phccclh@nus.edu.sg. School of Biological Sciences, Nanyang Technological University, Singapore. Electronic address: sksze@ntu.edu.sg.