A summary:
Aging correlates with increasing methylation. Epigenetic clocks measure age based on DNA methylation levels. Less methylation is associated with a younger phenotype.
Question: can we decrease our DNA methylation by following a regimen involving (some of) these demethylating agents:
- Procaine (or procainamide) – Gerovital H3?
- AKG alpha-ketoglutarate
- EGCG (plus possibly quercetin, resveratrol, curcumin, and sulforaphane)
- Vitamin C
- rapamycin
- reduced IGF (fasting, calorie restriction)
Research:
Progress on the role of DNA methylation in aging and longevity
Environmental signals have a widespread influence on the aging process. Epigenetic modification, e.g. DNA methylation, represents a link between genetic and environmental signals via the regulation of gene transcription. An abundance of literature indicates that aberrant epigenetic change occurs throughout the aging process at both the cellular and the organismal level. In particular, DNA methylation presents globally decreasing and site-specific increasing in aging. (…)
Intriguingly, abundant evidence has demonstrated that DNA methylation has a close association with aging, age-related diseases and longevity (…)
More importantly, accumulated studies suggest that age-dependent DNA methylation changes could be inversed by certain interventions, such as dietary control and chemicals, presenting the great potential of DNA methylation as a therapeutic target in preventing age-related diseases and promoting healthy aging.
DNA hypermethylation as a chemotherapy target.
It was found that accompanying DNA demethylation is a dramatic reactivation of the silenced genes and inhibition of cancer cell proliferation, promotion of cell apoptosis, or sensitization of cells to other chemotherapeutic reagents.
Dynamic DNA Methylation During Aging: A “Prophet” of Age-Related Outcomes
Currently, a growing number of studies have shown that dynamic DNA methylation throughout human lifetime exhibits strong correlation with age and age-related outcomes. Indeed, many researchers have built age prediction models with high accuracy based on age-dependent methylation changes in certain CpG loci. For now, DNA methylation based on epigenetic clocks, namely epigenetic or DNA methylation age, serves as a new standard to track chronological age and predict biological age. Measures of age acceleration (Δage, DNA methylation age – chronological age) have been developed to assess the health status of a person. In addition, there is evidence that an accelerated epigenetic age exists in patients with certain age-related diseases (e.g., Alzheimer’s disease, cardiovascular disease). (…)
Research has shown that semi-supercentenarians and their offspring have a relatively younger biological age as reflected by their decreased DNA methylation age (Horvath et al., 2015b).
Aging, Rejuvenation, and Epigenetic Reprogramming: Resetting the Aging Clock
Epigenetic regulation can occur by the direct methylation and demethylation of DNA bases, so called “cis-epigenetics” (Bonasio et al., 2010).
Demethylating Agents as Epigenetic Anticancer Therapeutics
Demethylating agents are a class of anti-cancer drugs which reduce cytosine methylation, promoting transcriptional activation of genes by virtue of reducing methylation in their promoter regions. Most compounds that inhibit methylation are inhibitors of DNA methyltransferases (DNMTs) that are responsible for methylating cytosine residues on DNA. Azacitidine and Decitabine are two such demethylating agents that are approved for use in myelodysplastic syndromes
Demethylating agents can be divided into two major structural groups: Nucleoside and nonnucleoside analogs.
Nucleoside analogs are structurally similar to cytosine and are currently being investigated in clinic. They are also known as azanucleosides, because they have a nitrogen instead of carbon at position 5 of the cytosine ring (Fig. 1A). Azacitidine, Decitabine and Zebularine are drugs of this group that are being tested for efficacy in clinical trials.
Nonnucleoside DNMT Inhibitors
Although it does not inhibit DNMTs directly in vitro, hydralazine, a vasodilator, can decrease the levels of DNMT1 and 3A protein in vivo [33]. It has also been shown that hydralazine interacts directly with DNMT1 DNA binding sites [34]. It can induce hypomethylation of the APC gene promoter leading to its reactivation in cervical cancer cell lines.
Unlike hydralazine, procainamide, a Na+ channel blocker, can inhibit DNMT activity in vitro. Its inhibition activity is relatively specific to DNMT1, leading to global loss of methylation. Also, a new derivative of procainamide (IM25) has been recently identified as a potent demethylating agent, which has greater demethylating activity than azacitidine and exhibits less cytotoxicity.
The antiarrhythmic drug procainamide has been known as an inhibitor of DNA methylation in human T cells. Its demethylating effect on T cells led to the over-expression of lymphocyte function associated antigen 1 that makes T cells autoreactive. Initially proposed as a perturbative of the interactions between DNMTs and CpG-rich sequences, procainamide was reported to specifically inhibit the maintenance methyltransferase activity of DNMT1 and to demethylate hypermethylated genes. Procainamide causes global DNA hypomethylation and restores the expression of the detoxifier gene glutathione S-transferase P1 (GSTP1).
Procainamide Is a Specific Inhibitor of DNA Methyltransferase 1
Tea catechins, particularly epigallocatechin-3-gallate (EGCG) has been reported to have DNA demethylating activity. Not only can it reduce the expression levels of DNMTs, but it also has inhibitory effects on HDACs resulting in increased histone acetylation, as described in one study[39].
Procaine Is a DNA-demethylating Agent with Growth-inhibitory Effects in Human Cancer Cells
Following this need to find new demethylating agents, we have tested the potential use of procaine, an anesthetic drug related to procainamide. Using the MCF-7 breast cancer cell line, we have found that procaine is a DNA-demethylating agent that produces a 40% reduction in 5-methylcytosine DNA content as determined by high-performance capillary electrophoresis or total DNA enzyme digestion. Procaine can also demethylate densely hypermethylated CpG islands, such as those located in the promoter region of the RARβ2 gene, restoring gene expression of epigenetically silenced genes. This property may be explained by our finding that procaine binds to CpG-enriched DNA. Finally, procaine also has growth-inhibitory effects in these cancer cells, causing mitotic arrest. Thus, procaine is a promising candidate agent for future cancer therapies based on epigenetics.(…)
Its long-established and safe use as a local anesthetic, with well-known pharmacological characteristics, may stimulate its prompt transition to preclinical and early clinical trials for epigenetics-based cancer treatments.
Most of you will have heard about Gerovital (GH3), a preparation developed by the Romanian scientist Ana Aslan and heavily promoted from the 1950s to 1980s. In the 1970s, the National Institute on Aging commissioned a thorough evaluation of the studies and claims surrounding Gerovital H3. The conclusion of that work was that, except for a possible mild monoamine oxidase (MAO) inhibitor effect that would potentially ameliorate depression, there was no scientifically credible evidence supporting the claims that procaine is beneficial in treating age‐related diseases or syndromes. But on the other hand in the 1970s nobody heard of epigenetic clocks and TETs, so perhaps if they had measured the patients’ epigenetic age they would have found some benefit to taking GH3…
Alpha‐ketoglutarate
Dietary alpha‐ketoglutarate promotes beige adipogenesis and prevents obesity in middle‐aged mice
AKG administration up‐regulated Prdm16 expression, which was correlated with an increase of DNA demethylation in the Prdm16 promoter. In summary, AKG supplementation promotes beige adipogenesis and alleviates HFD‐induced obesity in middle‐aged mice, which is associated with enhanced DNA demethylation of the Prdm16 gene (…)
Ten–eleven translocation family of proteins (TET) catalyze hydroxylation of 5mC to 5hmC, a key step in active DNA demethylation, which requires α‐ketoglutarate (AKG) as a cofactor (Tahiliani et al., 2009). Moreover, AKG integrates key pathways in cellular metabolism.(…)
We found that AKG is a rate‐limiting factor controlling DNA demethylation in the Prdm16 promoter, and its deficiency in progenitor cells profoundly attenuates brown adipogenesis.(…)
Our results suggested that dietary AKG up‐regulated Prdm16 expression and beige/brown adipogenesis partially through facilitating active DNA demethylation. Dietary supplementation of AKG increased intracellular levels of AKG and enhanced beige adipogenesis, which improved metabolic health of aged mice challenged with HFD. Because active DNA demethylation is not only limited to brown/beige adipogenesis but also presents in the differentiation of progenitor cells in other tissues, the dietary AKG intervention might have preventive effects in the senescence of other tissues as well, which warrant further studies.
Active DNA demethylation is mediated by the ten-eleven translocation hydroxylases (TETs), including TET1, 2 and 3. Importantly, TET catalytic reaction requires α-ketoglutarate (αKG), a key metabolite of the Krebs cycle, linking metabolism to epigenetic modifications and stem cell differentiation.(…)
Consistent with increased Prdm16 expression, the DNA methylation in these three regions was reduced during differentiation (Figure 3F), showing the occurrence of DNA demethylation.
The expression of all Tets, which catalyze 5hmC formation, was pronouncedly enhanced during brown adipogenic differentiation (Figure 3I), suggesting the importance of DNA demethylation during brown adipogenesis.
Dietary Compounds as Epigenetic Modulating Agents in Cancer
It has been reported that a diet rich in vegetables and fruits can significantly reduce the risk of cancer development, due to the action of phytochemicals which may regulate the expression of oncogenes and tumor suppressor genes. Remarkably, phytochemicals may act through epigenetic mechanisms such as modulation of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) activities. In general, cancer treatments involve the use of chemo-radio therapeutic agents, kinase inhibitors, personalized antibodies as well as compounds that stimulate the immune system. In particular, HDAC inhibitors and demethylating drugs modified gene expressions by reversing the aberrant epigenetic alterations acquired during tumorigenesis (Luczak and Jagodziński, 2006).(…)
Recent reports indicate that dietary supplements and natural compounds may restore the normal epigenetic marks which are altered during carcinogenesis. The phytochemicals most studied in cancer are epigallocatechin-gallate (EGCG), quercetin, resveratrol, curcumin, and SFN [sulforaphane]. (…) These effects are mediated, in part, by the modulation of epigenetic machinery which included the regulation of DNMTs and HDACs activities.(…)
Remarkably, EGCG is a potential epigenetic modifier of DNMTs and HDACs and restores epigenetically silenced genes in skin and cervical cancers. For instance, in skin cancer cells, EGCG significantly decreased the proteins levels of DNMT1, DNMT3a, and DNMT3b and modulated the HDAC activities allowing the transcriptional activation of tumor suppressor genes such as p16 INK4a and Cip1/p21. In esophageal cancer, EGCG induced apoptosis and inhibited cell growth of ECa109 cells through p16 gene demethylation. Moreover, EGCG reactivated the expression of WIF-1 (Wnt inhibitory factor-1) through promoter demethylation and inhibited cell growth by downregulating the Wnt canonical pathway in H460 and A549 lung cancer cell lines. (…)
Several studies indicate that curcumin has antioxidant, anti-inflammatory, anti-proliferative, anti-angiogenic, and anti-cancer properties. Moreover, this natural compound has been considered as an excellent non-toxic hypomethylating agent for breast cancer therapy. For instance, curcumin inhibited DNMT1 expression and restored the function of RASSF1A by promoter hypomethylation in estrogen positive MCF-7 breast cancer cell line.
Prolongevity interventions, including reduced growth hormone (GH) and insulin-like growth factor (IGF) signaling, CR, and rapamycin, also slow down ticking of the presumptive biological clock.
Using DNA Methylation Profiling to Evaluate Biological Age and Longevity Interventions
Caloric restriction:
Caloric restriction attenuates age-related changes of DNA methyltransferase 3a in mouse hippocampus.
Progress on the role of DNA methylation in aging and longevity
TETs
Role of TET enzymes in DNA methylation, development, and cancer
Until recently, DNA methylation was believed to be an irreversible epigenetic event associated with gene repression, which could only be alleviated through DNA replication. Thus, it was remarkable when ten eleven translocation protein 1 (TET1) was discovered and shown to be able to modify methylcytosine and potentially erase DNA methylation (…)
Disruption of epigenetic landscapes, including DNA methylation patterns, is a hallmark of cancer. Somatic mutations in genes (e.g., in DNMT3A) that encode for the machinery that establishes DNA methylation have been causally linked to malignant transformation. Interestingly, the activity of TET enzymes, which is involved in removing this epigenetic mark, has also emerged as an important tumor suppressor mechanism in cancer.(…)
Thus, precise regulation of DNA methylation patterns, which is partly mediated by TET enzymes, is important for normal development and provides a fundamental protection against cellular transformation.
Increasing the levels of vitamin C (ascorbic acid) has been shown to stimulate TET protein enzymatic activity in cultured cells as well as mouse tissues. This can be detected as increased levels of the cytosine oxidation products 5hmC, 5fC, and 5caC as well as a small reduction of global DNA methylation in the absence of changes in TET expression levels. Although the precise mechanism is unknown, it is likely that vitamin C interacts directly with the catalytic domain of TET proteins and provides a local reducing environment that increases recycling efficiency of the Fe(II) cofactor (Yin et al. 2013).
Vitamin C
Vitamin C induces Tet-dependent DNA demethylation and a blastocyst-like state in ES cells
Here we report that addition of vitamin C to mouse ES cells promotes Tet activity, leading to a rapid and global increase in 5hmC. This is followed by DNA demethylation of many gene promoters and upregulation of demethylated germline genes. (…)
Collectively, the results of this study establish vitamin C as a direct regulator of Tet activity and DNA methylation fidelity in ES cells.
Chromatin Dynamics during Cellular Reprogramming
Nutrients and cofactors present in the extracellular environment represent a final class of molecules that influence the epigenome and cellular reprogramming. A point in case is ascorbic acid (vitamin C), which has been shown to strongly enhance the efficiency and kinetics of reprogramming and to increase the quality of mouse iPSCs by preventing aberrant hypermethylation. Ascorbic acid presumably functions both as an antioxidant and as a cofactor for specific epigenetic modifiers such as the H3K36 HDMs Jmjd1a/1b. Furthermore, ascorbic acid was suggested to be a cofactor for H3K9 HDMs and Tet enzymes according to recent studies, which reported a global decrease of the repressive H3K9me2/3 marks and genome-wide DNA hypomethylation, respectively, in nascent iPSCs exposed to this compound. Together, these observations provide compelling new evidence for the tight communication between reprogramming-associated signaling molecules and TFs in order to rewire epigenetic regulatory circuits.
TET enzymes, TDG and the dynamics of DNA demethylation
Although the exact function of the TET proteins in ES cells needs further study, several recent publications are supportive of a role for TET in reprogramming of somatic cells to generate induced pluripotent stem cells (iPSCs). For example, at the early stage of transduction with the transcription factors Oct4, Klf4, Sox2 and c-Myc (collectively referred to as OKSM), Tet2 is recruited to the Nanog and Esrrb loci to activate their transcription. In addition, both Tet1 and Tet2 can associate with Nanog and facilitate iPSC generation in an enzymatic activity dependent manner. Remarkably, Tet1 overexpression can not only enhance reprogramming efficiency by promoting demethylation and reactivation of Oct4, but can also replace Oct4 in the iPSC reprogramming cocktail. Furthermore, beyond reprogramming mediated by OKSM, Tet1 and Tet2 seem to have distinct roles in reprogramming mediated by fusion of somatic cells to pluripotent cells.
David Sinclair: Reversal of ageing- and injury-induced vision loss by Tet-dependent epigenetic reprogramming
Ageing is a degenerative process leading to tissue dysfunction and death. A proposed cause of ageing is the accumulation of epigenetic noise, which disrupts youthful gene expression patterns that are required for cells to function optimally and recover from damage. Changes to DNA methylation patterns over time form the basis of an 'ageing clock’, but whether old individuals retain information to reset the clock and, if so, whether this would improve tissue function is not known.(…)
Having previously found evidence for epigenetic noise as an underlying cause of ageing, we wondered whether mammalian cells might retain a faithful copy of epigenetic information from earlier in life, analogous to Shannon's "observer" system in Information Theory, essentially a back-up copy of the original signal to allow for its reconstitution at the receiving end if information is lost or noise is introduced during transmission.(…)
Ten-Eleven-Translocation (TET) dioxygenases are known for their ability to remove DNA demethylation at CpG sites. Because Yamanaka factors promote in vitro reprogramming by upregulating Tet1 and Tet2, but have no effect on Tet3, we tested whether Tet1 and Tet2 were required for the beneficial effects of OSK on RGCs. Four weeks of OSK AAV expression significantly decreased DNA methylation age, and this was Tet1- and Tet2-dependent (Fig. 4i). Together, these results demonstrate that Tet-dependent in vivo reprogramming can restore youthful gene expression patterns, reverse the DNA methylation clock, and restore the function and regenerative capacity of a tissue as complex as the retina.(…)
In this study, we show that in vivo reprogramming of aged neurons can reverse DNA methylation age and allow them to regenerate and function as though they were young again. The requirement of the DNA demethylases Tet1 and Tet2 for this process indicates that altered
DNA methylation patterns may not just a measure of age but participants in ageing. These data lead us to conclude that mammalian cells retain a set of original epigenetic information, in the same way Shannon's observer stores information to ensure the recovery of lost information.
So, the question is: can we affect our epigenetic age by a taking a combination of the demethylating agents described above? If yes, what would the protocol be: doses, duration, etc.? What do you think?