Epigenetic drugs for Alzheimer's disease: hopes and challenges

Potential epigenomic co-management in rare diseases and epigenetic therapy

The purpose of this review is to highlight the impact of the alternative splicing process on human disease. Epigenetic regulation determines not only what parts of the genome are expressed but also how they are spliced. The recent progress in the field of epigenetics has important implications for the study of rare diseases. The role of epigenetics in rare diseases is a key issue in molecular physiology and medicine because not only rare diseases can benefit from epigenetic research, but can also provide useful principles for other common and complex disorders such as cancer, cardiovascular, type 2 diabetes, obesity, and neurological diseases. Predominantly, epigenetic modifications include DNA methylation, histone modification, and RNA-associated silencing. These modifications in the genome regulate numerous cellular activities. Disruption of epigenetic regulation process can contribute to the etiology of numerous diseases during both prenatal and postnatal life. Here, I discuss current knowledge about this matter including some current epigenetic therapies and future directions in the field by emphasizing on the RNA-based therapy via antisense oligonucleotides to correct splicing defects.

Novel Sustainable-by-Design HDAC Inhibitors for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) represents a global problem, with an estimation of the majority of dementia patients in low- and middle-income countries by 2050. Thus, the development of sustainable drugs has attracted much attention in recent years. In light of this, taking inspiration from the HDAC inhibitor vorinostat (1), we develop the first HDAC inhibitors derived from cashew nut shell liquid (CNSL), an inexpensive agro-food waste material. CNSL derivatives 8 and 9 display a HDAC inhibitory profile similar to 1, together with a more promising safety for 9 compared to 1. Moreover, both compounds and particularly 9 were able to effectively modulate glial cell-induced inflammation and to revert the pro-inflammatory phenotype. All these results demonstrate that the use of inexpensive food waste materials could be successfully applied for the development of accessible and sustainable drug candidates for the treatment of AD.

Pharmacogenetic considerations in the treatment of Alzheimer's disease

The practical pharmacogenetics of Alzheimer's disease (AD) is circumscribed to acetylcholinesterase inhibitors (AChEIs) and memantine. However, pharmacogenetic procedures should be applied to novel strategies in AD therapeutics including: novel AChEIs and neurotransmitter regulators, anti-Aβ treatments, anti-tau treatments, pleiotropic products, epigenetic drugs and combination therapies. Genes involved in the pharmacogenetic network are under the influence of the epigenetic machinery which regulates gene expression transcriptionally and post-transcriptionally, configuring the fundamentals of pharmacoepigenomics. Over 60% of AD patients present concomitant pathologies demanding additional treatments which increase the likelihood of drug-drug interactions. Lipid metabolism dysfunction is a pathogenic mechanism inherent to AD neurodegeneration. The therapeutic response to hypolipidemic compounds is influenced by the APOE and CYP genotypes. The development of novel compounds and the use of combination/multifactorial treatments require the implantation of pharmacogenomic procedures for the avoidance of ADRs and the optimization of therapeutics.

Epigenetics of dementia: understanding the disease as a transformation rather than a state

Alzheimer's disease and other idiopathic dementias are associated with epigenetic transformations. These transformations connect the environment and genes to pathogenesis, and have led to the investigation of epigenetic-based therapeutic targes for the treatment of these diseases. Epigenetic changes occur over time in response to environmental effects. The epigenome-based latent early-life associated regulation (LEARn) hypothetical model indicates that accumulated environmental hits produce latent epigenetic changes. These hits can alter biochemical pathways until a pathological threshold is reached, which appears clinically as the onset of dementia. The hypotheses posed by LEARn are testable via longitudinal epigenome-wide, envirome-wide, and exposome-wide association studies (LEWAS) of the genome, epigenome, and environment. We posit that the LEWAS design could lead to effective prevention and treatments by identifying potential therapeutic strategies. Epigenetic evidence suggests that dementia is not a suddenly occurring and sharply delineated state, but rather a gradual change in crucial cellular pathways, that transforms an otherwise healthy state, as a result of neurodegeneration, to a dysfunctional state. Evidence from epigenetics could lead to ways to detect, prevent, and reverse such processes before clinical dementia.

Epigenetic modifications of chronic hypoxia-mediated neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder affecting the elderly people. AD is characterized by progressive and gradual decline in cognitive function and memory loss. While familial early-onset AD is usually associated with gene mutations, the etiology of sporadic late-onset form of AD is largely unknown. It has been reported that environmental factors and epigenetic alterations significantly contribute to the process of AD. Our previous studies have documented that chronic hypoxia is one of the environmental factors that may trigger the AD development and aggravate the disease progression. In this review, we will summarize the pathological effects of chronic hypoxia on the onset and development of AD and put forward the possible molecule mechanisms underlying the chronic hypoxia mediated AD pathogenesis. Finally, we propose that epigenetic regulations may represent new opportunity for the therapeutic intervention of this disease.

Epigenetics: a novel therapeutic approach for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia in the elderly. It is characterized by the deposition of two forms of aggregates within the brain, the amyloid β plaques and tau neurofibrillary tangles. Currently, no disease-modifying agent is approved for the treatment of AD. Approved pharmacotherapies target the peripheral symptoms but they do not prevent or slow down the progression of the disease. Although several disease-modifying immunotherapeutic agents are in clinical development, many have failed due to the lack of efficacy or serious adverse events. Epigenetic changes including DNA methylation and histone modifications are involved in learning and memory and have been recently highlighted for holding promise as potential targets for AD therapeutics. Dynamic and latent epigenetic alterations are incorporated in AD pathological pathways and present valuable reversible targets for AD and other neurological disorders. The approval of epigenetic drugs for cancer treatment has opened the door for the development of epigenetic drugs for other disorders including neurodegenerative diseases. In particular, methyl donors and histone deacetylase inhibitors are being investigated for possible therapeutic effects to rescue memory and cognitive decline found in such disorders. This review explores the area of epigenetics for potential AD interventions and presents the most recent findings in this field.