Sunday, November 9, 2008

Vitamin B3 and Alzheimers Disease

9/11/2008 4:37PM

Vitamin B3 and Alzheimers Disease

Nicotinamide is a form of Vitamin B3. This is a promising study because this compound was found to target a key and early initiator of amyloid plaque formation in the brain. That process is tau phosphorylation which is implicated in many neurodegenerative conditions. Nicotinamide can be purchased as supplement and is generally safe but at very high doses can be toxic.

The Science Daily news release is available here.

The Journal of Neuroscience, November 5, 2008, 28(45):11500-11510; doi:10.1523/JNEUROSCI.3203-08.2008
Nicotinamide Restores Cognition in Alzheimer's Disease Transgenic Mice via a Mechanism Involving Sirtuin Inhibition and Selective Reduction of Thr231-Phosphotau
Kim N. Green,1 Joan S. Steffan,2 Hilda Martinez-Coria,1 Xuemin Sun,3 Steven S. Schreiber,3,5 Leslie Michels Thompson,1,2,4 and Frank M. LaFerla1
Departments of 1Neurobiology and Behavior, 2Psychiatry and Human Behavior, 3Neurology, 4Biological Chemistry, and 5Anatomy and Neurobiology, University of California, Irvine, Irvine, California 92697-4545
Correspondence should be addressed to Frank M. LaFerla, Department of Neurobiology and Behavior, University of California, Irvine, 1109 Gillespie Neuroscience Building, Irvine, CA 92697-4545. Email:
Memory loss is the signature feature of Alzheimer's disease, and therapies that prevent or delay its onset are urgently needed. Effective preventive strategies likely offer the greatest and most widespread benefits. Histone deacetylase (HDAC) inhibitors increase histone acetylation and enhance memory and synaptic plasticity. We evaluated the efficacy of nicotinamide, a competitive inhibitor of the sirtuins or class III NAD+-dependent HDACs in 3xTg-AD mice, and found that it restored cognitive deficits associated with pathology. Nicotinamide selectively reduces a specific phospho-species of tau (Thr231) that is associated with microtubule depolymerization, in a manner similar to inhibition of SirT1. Nicotinamide also dramatically increased acetylated -tubulin, a primary substrate of SirT2, and MAP2c, both of which are linked to increased microtubule stability. Reduced phosphoThr231-tau was related to a reduction of monoubiquitin-conjugated tau, suggesting that this posttranslationally modified form of tau may be rapidly degraded. Overexpression of a Thr231-phospho-mimic tau in vitro increased clearance and decreased accumulation of tau compared with wild-type tau. These preclinical findings suggest that oral nicotinamide may represent a safe treatment for AD and other tauopathies, and that phosphorylation of tau at Thr231 may regulate tau stability.

No comments: