Therapeutic approaches for Alzheimer’s disease (AD) are guided by four disease characteristics: amyloid plaques, neurofibrillar
tangles (NFT), neurodegeneration, and dementia. Amyloid plaques are composed largely of 4 kDa β-amyloid (Aβ) peptides, with
the more amyloidogenic, 42 amino acid form (Aβ42) as the primary species. Because multiple, rare mutations that cause early-onset,
familial AD lead to increased production or aggregation of Aβ42, amyloid therapeutics aim to reduce the amount of toxic Aβ42
aggregates. Amyloid-based therapies include γ-secretase inhibitors and modulators, BACE inhibitors, aggregation blockers,
catabolism inducers, and anti-Aβ biologics. Tangles are composed of paired helical filaments of hyperphosphorylated tau protein.
Tau-based therapeutics include kinase inhibitors, microtubule stabilizers, and catabolism inducers. Therapeutic strategies
for neurodegeneration target multiple mechanisms, including excitotoxicity, mitochondrial dysfunction, oxidative damage, and
inflammation or stimulation of neuronal viability. Although not disease modifying, cognition enhancers are important to treat
the symptom of dementia. Strategies for cognition enhancement include cholinesterase inhibitors, and other approaches to enhance
the signaling of cholinergic and glutamatergic neurons. In summary, plaques, tangles, neurodegeneration and dementia guide
the development of multiple therapeutic approaches for AD and are the subject of this review.
Keywords Alzheimer’s disease - Therapeutics - Amyloid - Tau - Dementia - Cognition enhancement - Secretase - Neurodegeneration - Plaque - Tangle