Some possible HDAC inhibitors to try:
1. ALCAR (donates acetyl groups) http://www.ncbi.nlm....pubmed/19755853
2. Resistant Starch (acetate, propionate, butyrate)
3. Triacetin http://www.longecity...-78#entry721627
4. Sodium Butyrate
5. Pyruvate
"Interestingly, pyruvate, butyrate, and propionate were identified as inhibitors of HDAC1 and HDAC3..."
http://www.ncbi.nlm....les/PMC3254183/
Crit Rev Biochem Mol Biol. 2011 Jun;46(3):181-99. doi: 10.3109/10409238.2011.557713. Epub 2011 Apr 5.
Metabolism as a key to histone deacetylase inhibition.
Abstract
There is growing interest in the epigenetic mechanisms that are dysregulated in cancer and other human pathologies. Under this broad umbrella, modulators of histone deacetylase (HDAC) activity have gained interest as both cancer chemopreventive and therapeutic agents. Of the first generation, FDA-approved HDAC inhibitors to have progressed to clinical trials, vorinostat represents a "direct acting" compound with structural features suitable for docking into the HDAC pocket, whereas romidepsin can be considered a prodrug that undergoes reductive metabolism to generate the active intermediate (a zinc-binding thiol). It is now evident that other agents, including those in the human diet, can be converted by metabolism to intermediates that affect HDAC activity. Examples are cited of short-chain fatty acids, seleno-α-keto acids, small molecule thiols, mercapturic acid metabolites, indoles, and polyphenols. The findings are discussed in the context of putative endogenous HDAC inhibitors generated by intermediary metabolism (e.g. pyruvate), the yin-yang of HDAC inhibition versus HDAC activation, and the screening assays that might be most appropriate for discovery of novel HDAC inhibitors in the future.
http://www.ncbi.nlm....pubmed/18789002
Biochem J. 2009 Jan 1;417(1):379-89. doi: 10.1042/BJ20081132.
Colon cancer cells maintain low levels of pyruvate to avoid cell death caused by inhibition of HDAC1/HDAC3.
Abstract
Human colon cancer cells and primary colon cancer silence the gene coding for LDH (lactate dehydrogenase)-B and up-regulate the gene coding for LDH-A, resulting in effective conversion of pyruvate into lactate. This is associated with markedly reduced levels of pyruvate in cancer cells compared with non-malignant cells. The silencing of LDH-B in cancer cells occurs via DNA methylation, with involvement of the DNMTs (DNA methyltransferases) DNMT1 and DNMT3b. Colon cancer is also associated with the expression of pyruvate kinase M2, a splice variant with low catalytic activity. We have shown recently that pyruvate is an inhibitor of HDACs (histone deacetylases). Here we show that pyruvate is a specific inhibitor of HDAC1 and HDAC3. Lactate has no effect on any of the HDACs examined. Colon cancer cells exhibit increased HDAC activity compared with non-malignant cells. HDAC1 and HDAC3 are up-regulated in colon cancer cells and in primary colon cancer, and siRNA (small interfering RNA)-mediated silencing of HDAC1 and HDAC3 in colon cancer cells induces apoptosis. Colon cancer cells silence SLC5A8, the gene coding for a Na(+)-coupled pyruvate transporter. Heterologous expression of SLC5A8 in the human colon cancer cell line SW480 leads to inhibition of HDAC activity when cultured in the presence of pyruvate. This process is associated with an increase in intracellular levels of pyruvate, increase in the acetylation status of histone H4, and enhanced cell death. These studies show that cancer cells effectively maintain low levels of pyruvate to prevent inhibition of HDAC1/HDAC3 and thereby to evade cell death.
http://www.ncbi.nlm....pubmed/26057947
Exp Neurol. 2015 Sep;271:145-54. doi: 10.1016/j.expneurol.2015.06.008. Epub 2015 Jun 7.
Systemic pyruvate administration markedly reduces neuronal death and cognitive impairment in a rat model of Alzheimer's disease.
Abstract
Alzheimer's disease (AD) is a major neurodegenerative disease of old age, characterized by progressive cognitive impairment, dementia and atrophy of the central nervous system. Amyloid-β (Aβ) oligomers are derived from proteolytic cleavage of amyloid precursor protein (APP) and recognized as the primary neurotoxic agents in AD. Pyruvate has a protective effect against Aβ oligomer-induced neuronal cell death and inhibition of long-term potentiation (LTP) in hippocampal slice cultures, leading us to investigate the effect of systemic pyruvateadministration in an intracerebroventricular Aβ oligomer infusion model. We found that sodium pyruvate (500mg/kg, intraperitoneally) improved neuron survival and sustained improvement in cognitive function as assessed by the Morris water maze. Pyuvate prevented the Aβ oligomer-induced inhibition of LTP and protein phosphatase 2A (PP2A) activation. Pyruvate suppressed the Aβ oligomer-induced poly[adenosine diphosphate (ADP) ribose] polymerase-1 (PARP-1) activity and ameliorated Aβ oligomer-induced decrease of NAD(+) level. Moreover, pyuvate, but not lactate, decreased reactive oxygen species (ROS) accumulation in hippocampus of Aβ1-42 oligomer-injection rat model. These results suggest that systemic pyruvate administration could significantly ameliorate Aβ oligomer-induced spatial learning and memory impairment by the improvement of neuron survival and prevention of LTP inhibition, and the beneficial effect of pyruvate could be linked, at least in part, to the elimination of ROS accumulation, prevention of PP2A activation, amelioration of NAD(+) level and suppression of PARP-1 activity.
http://www.ncbi.nlm....pubmed/15855333
Diabetes. 2005 May;54(5):1452-8.
Pyruvate administered after severe hypoglycemia reduces neuronal death and cognitive impairment.
Abstract
Hypoglycemia-induced brain injury is a significant obstacle to optimal blood glucose control in diabetic patients. Severe hypoglycemia triggers a cascade of events in vulnerable neurons that may culminate in cell death even after glucose normalization. A key event in this cascade is the activation of poly(ADP-ribose) polymerase-1 (PARP-1). Activated PARP-1 consumes cytosolic NAD, and because NAD is required for glycolysis, hypoglycemia-induced PARP-1 activation may render cells unable to use glucose even when glucose availability is restored. Pyruvate, however, can be metabolized in the absence of cytosolic NAD. Here we tested whether pyruvate could improve the outcome in rats subjected to insulin-induced hypoglycemia by terminating hypoglycemia with either glucose alone or glucose plus pyruvate. In the four brain regions studied--CA1, subiculum, dentate gyrus of the hippocampus, and piriform cortex--the addition of pyruvate reduced neuron death by 70-90%. Improved neuron survival was also observed when pyruvate delivery was delayed for up to 3 h. The improved neuron survival was accompanied by a sustained improvement in cognitive function as assessed by the Morris water maze. These results suggest that pyruvate may significantly improve the outcome after severe hypoglycemia by circumventing a sustained impairment in neuronal glucose utilization resulting from PARP-1 activation.
"The blood-brain barrier normally transports pyruvate at a rate much slower than glucose, but prior work suggests that significant pyruvate entry to the brain can be achieved by elevating plasma pyruvate concentrations..."
http://www.ncbi.nlm....pubmed/11588201
J Neurosci. 2001 Oct 15;21(20):RC171.
Protection by pyruvate against transient forebrain ischemia in rats.
Abstract
Pyruvate has a remarkable protective effect against zinc neurotoxicity. Because zinc neurotoxicity is likely one of the key mechanisms of ischemic brain injury, the neuroprotective effect of pyruvate was tested in a rat model of transient forebrain ischemia. Control experiments in mouse cortical culture showed that pyruvate almost completely blocked zinc toxicity but did not attenuate calcium-overload neuronal death. Adult rats subjected to 12 min forebrain ischemia exhibited widespread zinc accumulation and neuronal death throughout hippocampus and cortex 72 hr after reperfusion. However, rats injected intraperitoneally with sodium pyruvate (500-1000 mg/kg) within 1 hr after 12 min forebrain ischemia showed almost no neuronal death. In addition, the mortality was markedly decreased in the pyruvate-protected groups (3.8%) compared with the NaCl-injected control group (58.1%). The neuroprotective effect persisted even at 30 d after the insult. The spectacular protection without noticeable side effects makes pyruvate a promising neuroprotectant in human ischemic stroke.
http://www.ncbi.nlm....les/PMC3160172/
J Neurosci. 2011 Jan 12;31(2):764-74. doi: 10.1523/JNEUROSCI.5052-10.2011.
HDAC3 is a critical negative regulator of long-term memory formation.
McQuown SC1,
Barrett RM,
Matheos DP,
Post RJ,
Rogge GA,
Alenghat T,
Mullican SE,
Jones S,
Rusche JR,
Lazar MA,
Wood MA.
Abstract
Gene expression is dynamically regulated by chromatin modifications on histone tails, such as acetylation. In general, histone acetylation promotes transcription, whereas histone deacetylation negatively regulates transcription. The interplay between histone acetyltranserases and histone deacetylases (HDACs) is pivotal for the regulation of gene expression required for long-term memory processes. Currently, very little is known about the role of individual HDACs in learning and memory. We examined the role of HDAC3 in long-term memory using a combined genetic and pharmacologic approach. We used HDAC3-FLOX genetically modified mice in combination with adeno-associated virus-expressing Cre recombinase to generate focal homozygous deletions of Hdac3 in area CA1 of the dorsal hippocampus. To complement this approach, we also used a selective inhibitor of HDAC3, RGFP136 [N-(6-(2-amino-4-fluorophenylamino)-6-oxohexyl)-4-methylbenzamide]. Immunohistochemistry showed that focal deletion or intrahippocampal delivery of RGFP136 resulted in increased histone acetylation. Both the focal deletion of HDAC3 as well as HDAC3 inhibition via RGFP136 significantly enhanced long-term memory in a persistent manner. Next we examined expression of genes implicated in long-term memory from dorsal hippocampal punches using quantitative reverse transcription-PCR. Expression of nuclear receptor subfamily 4 group A, member 2 (Nr4a2) and c-fos was significantly increased in the hippocampus of HDAC3-FLOX mice compared with wild-type controls. Memory enhancements observed in HDAC3-FLOX mice were abolished by intrahippocampal delivery of Nr4a2 small interfering RNA, suggesting a mechanism by which HDAC3 negatively regulates memory formation. Together, these findings demonstrate a critical role for HDAC3 in the molecular mechanisms underlying long-term memory formation.
Edited by lostfalco, 15 November 2015 - 03:03 AM.