Levels Of Histone Deacetylase Research Articles

DNA methyltransferase- and histone deacetylase-mediated epigenetic alterations induced by low-level methylmercury exposure disrupt neuronal development.

Methylmercury (MeHg) is a chemical substance that causes adverse effects on fetal development. However, the molecular mechanisms by which environmental MeHg affects fetal development have not been clarified. Recently, it has been suggested that the toxic effects of chemicals on fetal development are related alterations in epigenetics, such as DNA methylation and histone modification. In order to analyze the epigenetic effects of low-level MeHg exposure on neuronal development, we evaluated neuronal development both in vivo and in vitro. Pregnant mice (C57BL/6J) were orally administrated 3mg/kg of MeHg once daily from embryonic day 12-14. Fetuses were removed on embryonic day 19 and brain tissues were collected. LUHMES cells were treated with 1nM of MeHg for 6days and collected on the last day of treatment. In both in vivo and in vitro samples, MeHg significantly suppressed neurite outgrowth. Decreased acetylated histone H3 (AcH3) levels and increased histone deacetylase (HDAC) 3 and HDAC6 levels were observed in response to MeHg treatment in both in vivo and in vitro experiments. In addition, increased DNA methylation and DNA methyltransferase 1 (DNMT1) levels were observed in both in vivo and in vitro experiments. The inhibition of neurite outgrowth resulting from MeHg exposure was restored by co-treatment with DNMT inhibitor or HDAC inhibitors. Our results suggest that neurological effects such as reduced neurite outgrowth due to low-level MeHg exposure result from epigenetic changes, including a decrease in AcH3 via increased HDAC levels and an increase in DNA methylation via increased DNMT1 levels.

Modulation of histone deacetylase 2 (HDAC2) drives neuronal gene expression, mitochondrial dynamics and AD pathophysiology in human stem cell derived neurons

AbstractBackgroundHistone deacetylase 2 (HDAC2) is a major HDAC protein in the adult brain and has been shown to regulate many neuronal genes. Aberrant expression of HDAC2 and subsequent dysregulation of neuronal gene expression has been implicated in Alzheimer’s disease (AD) and brain aging. In vitro models of AD and other neurodegenerative disorders using human induced pluripotent stem cells (hiPSCs) are being increasingly utilized and have provided novel insights into disease mechanisms. However, the role of HDAC2 in living, human neurons and how its manipulation in an AD model may affect disease phenotypes has not been investigated.MethodWe used human induced pluripotent stem cells and lentiviral‐mediated manipulation of HDAC2 in hiPSC‐derived neurons to study the effects of increasing or decreasing HDAC2 expression on neuronal mitochondrial gene expression, morphology, and AD phenotypes.ResultIn this study, we show that levels of HDAC2 naturally decrease as hiPSCs are differentiated towards a neuronal lineage and that this suppression of HDAC2 inversely corresponds to an increase in neuronal‐specific isoforms of Endophilin‐B1, a multifunctional protein involved in mitochondrial dynamics. Manipulation of HDAC2 and Endophilin‐B1 using lentiviral approaches shows that knock‐down of HDAC2 or overexpression of Endophilin‐B1 promote mitochondrial elongation in hiPSC‐derived neurons, but HDAC2 knock‐down specifically influences genes regulating neuronal mitochondrial dynamics. We also observe that the endogenous decrease in HDAC2 levels upon neuronal differentiation also correlates with natural increases in neuronal activity and knock‐down of HDAC2 in differentiated neurons increases expression of genes related to neuronal synapses and further increases neuronal firing. Finally, we demonstrate that knock‐down of HDAC2 reduces amyloid beta peptides and the phospho/total Tau ratio in iPSC‐derived neurons.ConclusionCollectively, our study demonstrates that HDAC2 regulates key neuronal functional and bioenergetic pathways in hiPSC‐derived neurons and suggests that HDAC2 may represent a novel therapeutic target for AD.

Role of Altered Expression, Activity and Sub-cellular Distribution of Various Histone Deacetylases (HDACs) in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

Histone deacetylases (HDACs) have been described to have both neurotoxic and neuroprotective roles, and partly, depend on its sub-cellular distribution. HDAC inhibitors have a long history of use in the treatment of various neurological disorders including epilepsy. Key role of HDACs in GABAergic neurotransmission, synaptogenesis, synaptic plasticity and memory formation was demonstrated whereas very less is known about their role in drug-resistant epilepsy pathologies. The present study was aimed to investigate the changes in the expression of HDACs, activity and its sub-cellular distribution in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) patients. For this study, surgically resected hippocampal tissue specimens of 28 MTLE-HS patients and 20 hippocampus from post-mortem cases were obtained. Real-time PCR was done to analyse the mRNA expression. HDAC activity and the protein levels of HDACs in cytoplasm as well as nucleus were measured spectrophotometrically. Further, sub-cellular localization of HDACs was characterized by immunofluorescence. Significant upregulation of HDAC1, HDAC2, HDAC4, HDAC5, HDAC6, HDAC10 and HDAC11 mRNA were observed in MTLE-HS. Alterations in the mRNA expression of glutamate and gamma-aminobutyric acid (GABA) receptor subunits have been also demonstrated. We observed significant increase of HDAC activity and nuclear level of HDAC1, HDAC2, HDAC5 and HDAC11 in the hippocampal samples obtained from patients with MTLE-HS. Moreover, we found altered cytoplasmic level of HDAC4, HDAC6 and HDAC10 in the hippocampal sample obtained from patients with MTLE-HS. Alterations in the level of HDACs could potentially be part of a dynamic transcription regulation associated with MTLE-HS. Changes in cytoplasmic level of HDAC4, 6 and 10 suggest that cytoplasmic substrates may play a crucial role in the pathophysiology of MTLE-HS. Knowledge regarding expression pattern and sub-cellular distribution of HDACs may help to devise specific HDACi therapy for epilepsy.

Cracking a cancer code histone deacetylation in epigenetic: the implication from molecular dynamics simulations on efficacy assessment of histone deacetylase inhibitors

Epigenetic changes, histone acetylation and deacetylation in chromatin have been intensively studied due to their significance in regulating the gene expression. According to the type of tumor, the levels of histone deacetylases (HDAC) are varied. HDAC inhibitors are a new promising class of compounds that inhibit the proliferation of tumor cells. In this study, the inhibitory efficacy of some HDAC inhibitors such as vorinostat, panobinostat, abexinostat, belinostat, resminostat, dacinostat and pracinostat was studied using molecular dynamics simulation. The inhibitory efficacy was estimated by computing the enzyme’s stability, positional stability of the individual amino acids and interaction energies of HDLP-inhibitor complexes. It is hoped that this investigation may improve our understanding of the atomic-level description of the inhibitor binding site and how the HDAC inhibitors change the environment of the enzyme’s active site. The results obtained from the root-mean-square deviation, the radius of gyration, solvent-accessible surface area, root-mean-square fluctuation, stride server and Ramachandran plot have revealed that the stability of HDLP enzyme with vorinostat, panobinostat and abexinostat is higher than the other studied complexes. According to the calculated values for MM-PBSA, LIE, semi-LIE binding free energies and interaction energies, the stability of the HDLP enzyme varies as panobinostat > abexinostat > vorinostat where resminostat complex showed relatively low stability. The ligandability and drugability values also give the same trend as above. The findings revealed that the panobinostat and abexinostat are potential lead compounds as reference inhibitor vorinostat. Therefore, it is possible to use these drugs as HDAC inhibitors in clinical practices. Also, the outcomes of this study could be utilized to identify new inhibitors for clinical research. Communicated by Ramaswamy H. Sarma

P.548 The effects of clozapine on cognitive functioning in schizophrenia

Evidence indicates that the disruption of epigenetic processes might play an important role in the development of schizophrenia symptoms. The present study investigated the role of histone acetylation in the development of sensorimotor gating deficits in a neurodevelopmental model of schizophrenia based on prenatal administration of methylazoxymethanol (MAM) at embryonic day 17.Valproic acid (VPA), an inhibitor of class I histone deacetylases, was administered (250 mg/kg, twice a day for 7 consecutive days) in early adolescence (23rd–29th day) or early adulthood (63rd–69th day) to rats. The effect of VPA treatment on the sensorimotor gating deficits induced by prenatal MAM administration was analyzed in adult rats at postnatal day 70 (P70). In addition, the effects of VPA administration (at the same doses) on MAM-induced changes in the levels of histone H3 acetylation at lysine 9 (H3K9ac) and histone deacetylase 2 (HDAC2) in the medial prefrontal cortex (mPFC) were determined at P70 using Western blot.VPA administration in either adolescence or early adulthood prevented the sensorimotor gating deficits induced by MAM. However, VPA administration in early adolescence or early adulthood did not alter H3K9ac levels induced by MAM. In contrast, VPA administration in either adolescence or adulthood prevented the increase in HDAC2 level evoked by MAM.Prenatal MAM administration impaired histone acetylation in the mPFC, which might be involved in the development of some of the neurobehavioral deficits (i.e., sensorimotor gating deficits) associated with schizophrenia. Blockade of HDAC2 might prevent the disruption of sensorimotor gating in adulthood.

Repeated stress exposure in mid-adolescence attenuates behavioral, noradrenergic, and epigenetic effects of trauma-like stress in early adult male rats

Stress in adolescence can regulate vulnerability to traumatic stress in adulthood through region-specific epigenetic activity and catecholamine levels. We hypothesized that stress in adolescence would increase adult trauma vulnerability by impairing extinction-retention, a deficit in PTSD, by (1) altering class IIa histone deacetylases (HDACs), which integrate effects of stress on gene expression, and (2) enhancing norepinephrine in brain regions regulating cognitive effects of trauma. We investigated the effects of adolescent-stress on adult vulnerability to severe stress using the single-prolonged stress (SPS) model in male rats. Rats were exposed to either (1) adolescent-stress (33–35 postnatal days) then SPS (58–60 postnatal days; n = 14), or (2) no adolescent-stress and SPS (58–60 postnatal days; n = 14), or (3) unstressed conditions (n = 8). We then measured extinction-retention, norepinephrine, HDAC4, and HDAC5. As expected, SPS exposure induced an extinction–retention deficit. Adolescent-stress prior to SPS eliminated this deficit, suggesting adolescent-stress conferred resiliency to adult severe stress. Adolescent-stress also conferred region-specific resilience to norepinephrine changes. HDAC4 and HDAC5 were down-regulated following SPS, and these changes were also modulated by adolescent-stress. Regulation of HDAC levels was consistent with the pattern of cognitive effects of SPS; only animals exposed to SPS without adolescent-stress exhibited reduced HDAC4 and HDAC5 in the prelimbic cortex, hippocampus, and striatum. Thus, HDAC regulation caused by severe stress in adulthood interacts with stress history such that seemingly conflicting reports describing effects of adolescent stress on adult PTSD vulnerability may stem in part from dynamic HDAC changes following trauma that are shaped by adolescent stress history.

Fine particulate matter exposure promotes M2 macrophage polarization through inhibiting histone deacetylase 2 in the pathogenesis of chronic obstructive pulmonary disease.

BackgroundChronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality globally. Fine particulate matter (PM2.5) has been indicated to be a major detrimental risk factor for COPD by numerous epidemiological studies. Histone deacetylase 2 (HDAC2), a critical regulator of chromatin remodeling, plays a pivotal role in the development of COPD. However, the underlying mechanisms regarding the relationship between PM2.5 and HDAC2 in the pathogenesis of COPD have yet to be elucidated. In the present study, we aim to investigate the role and the underlying mechanism of HDAC2 in the development of PM2.5-induced COPD.MethodsThe effects of PM2.5 exposure on M2 macrophage polarization and the expression levels of HDAC2 were examined in vitro. The influence of HDAC2 deficiency on M2 macrophage polarization and the pathogenesis of COPD was investigated in a PM2.5-induced mouse model.ResultsPM2.5 exposure down-regulated the protein level of HDAC2 and enhanced M2 macrophage polarization in vitro. In the COPD murine model, myeloid-specific deficiency of HDAC2 augmented PM2.5-induced M2 polarization of alveolar macrophages (AMs) and up-regulation of tumor necrosis factor (TGF)-β, matrix metallopeptidase (MMP)-9, and MMP-12 in lung tissue, which resulted in more prominent lung function deterioration, airspace enlargement, alveolar wall destruction, and airway remodeling, indicating a key role of HDAC2 in the pathogenesis of PM2.5-induced COPD.ConclusionsPM2.5 facilitated M2 polarization by inhibiting HDAC2, leading to the development of COPD. Targeting of HDAC2 would provide a novel approach to prevent the development of PM2.5 exposure-induced COPD.

Isoflurane promotes proliferation of squamous cervical cancer cells through mTOR-histone deacetylase 6 pathway

This study investigated the effect of isoflurane on the proliferation of squamous cervical cancer cells, with focus on histone deacetylase 6 that is closely related to carcinogenesis. Squamous cervical cancer cells SiHa and Caski were exposed to 1%, 2%, or 3% isoflurane for 2 h, respectively. Cell proliferation was measured with the cell counting kit (CCK-8) assay and determined by BrdU assay. Expression of histone deacetylase 6, phospho-AKT, phospho-mTOR, and proliferating cell nuclear antigen (PCNA) was assessed by Western blot. In order to block the histone deacetylase 6 (HDAC6) expression, siRNA transfection was performed. Isoflurane significantly promoted the proliferation of both SiHa and Caski cells, accompanied by upregulation of PCNA protein expression. Isoflurane increased the level of histone deacetylase 6 protein expression in both cells, and knockdown of histone deacetylase 6 attenuated the pro-proliferation effects of isoflurane. Additionally, activation of AKT/mTOR was found after isoflurane treatment, and mTOR inhibition abolished isoflurane-induced histone deacetylase 6 expression. However, inhibition of AKT phosphorylation had no effect on the expression of histone deacetylase 6 mediated by isoflurane. In conclusion, Isoflurane enhanced proliferation of cervical cancer cells through upregulation of histone deacetylase 6, which was associated with mTOR-dependent pathway, but not AKT-mediated pathway.

Histone Deacetylase 1 and Sirtuin 1 Expression in Psoriatic Skin: A Comparison between Guttate and Plaque Psoriasis.

Abnormal histone modification by histone deacetylases (HDACs), including HDAC1 and sirtuin 1 (SIRT1), has been reported to play an important role in the pathogenesis of psoriasis by altering cell proliferation, differentiation, and inflammation. However, findings on the expression level of HDACs in psoriatic skin lack consistency. We assessed the expression of HDAC1, SIRT1, p63, and proliferating cell nuclear antigen (PCNA) in skin tissues from 23 patients with psoriasis (15 with plaque psoriasis and eight with guttate psoriasis) and five healthy individuals using immunohistochemistry, and analyzed their associations with clinical phenotypes of the disease. The expression of HDAC1 and keratinocyte proliferative markers, such as p63 and PCNA significantly increased, whereas that of SIRT1 decreased in the basal layer (p < 0.05) of the patients with psoriasis compared to those in healthy controls. Among the patients with psoriasis, expression of HDAC1, p63, and PCNA was significantly higher in plaque psoriasis than in guttate psoriasis. There was no significant differences in the level of SIRT1 between the two clinical phenotypes. The findings of this study suggest that histone modifications are involved in the pathogenesis of psoriasis and may contribute to the formation of clinical phenotypes.

Muscone Ameliorates Synaptic Dysfunction and Cognitive Deficits in APP/PS1 Mice.

Dysfunction of synaptic plasticity leads to memory impairment in Alzheimer's disease (AD). Muscone (Mus) has shown neuroprotective effects in cerebral ischemic models. However, little is known of Mus effects on AD. To investigate the effects of Mus on memory functions and synaptic plasticity in 6-month-old APP/PS1 double-transgenic mice and explore the potential mechanisms. Mus was intraperitoneally injected into APP/PS1 or wild-type mice, and cognitive function was assessed by Novel object recognition and Morris water maze tests. The levels of amyloid-β (Aβ) were evaluated by immunofluorescence staining and ELISA. Synaptic morphology and plasticity were evaluated by Golgi staining and long-term potentiation. Cell viability was examined by Cell Counting Kit-8 assay. The protein levels of histone deacetylase 2 (HDAC2) were accessed by western blotting and Immunofluorescence staining. The protein levels of microtubule associated protein 2 and synaptophysin were analyzed by immunofluorescence staining. The ubiquitination of HDAC2 was examined by co-immunoprecipitation. The interaction of Mus with HDAC2 was predicted by molecular docking analysis. Mus treatment attenuated memory dysfunction, reduced Aβ level, and enhanced synaptic plasticity in APP/PS1 mice. In addition, Mus treatment decreased the level of HDAC2 in the hippocampus of APP/PS1 mice and Aβ1-42-induced primary neurons, which might be associated with increased HDAC2 ubiquitination induced by HDAC2 and Mus interaction. Mus protected against synaptic plasticity and memory impairment in APP/PS1 mice, and enhanced HDAC2 degradation via ubiquitination, indicating that Mus was a potential drug for AD treatment.

L1CAM Beneficially Inhibits Histone Deacetylase 2 Expression under Conditions of Alzheimer's Disease.

Cognitive capacities in Alzheimer's Disease (AD) are impaired by an epigenetic blockade mediated by histone deacetylase 2 (HDAC2), which prevents the transcription of genes that are important for synaptic plasticity. Investigation of the functional relationship between cell adhesion molecule L1 and HDAC2 in AD. Cultures of dissociated cortical and hippocampal neurons from wild-type or L1-deficient mice were treated with Aβ1-42 for 24 h. After removal of Aβ1-42 cells were treated with the recombinant L1 extracellular domain (rL1) for 24 h followed by immunohistochemistry, western blotting, and reverse transcription PCR to evaluate the interaction between L1 and HDAC2. Aβ and HDAC2 protein levels were increased in APPSWE/L1+/- mutant brains compared to APPSWE mutant brains. Administration of the recombinant extracellular domain of L1 to cultured cortical and hippocampal neurons reduced HDAC2 mRNA and protein levels. In parallel, reduced phosphorylation levels of glucocorticoid receptor 1 (GR1), which is implicated in regulating HDAC2 levels, was observed in response to L1 administration. Application of a glucocorticoid receptor inhibitor reduced Aβ-induced GR1 phosphorylation and prevented the increase in HDAC2 levels. HDAC2 protein levels were increased in cultured cortical neurons from L1-deficient mice. This change could be reversed by the administration of the recombinant extracellular domain of L1. Our results suggest that some functionally interdependent activities of L1 and HDAC2 contribute to ameliorating the phenotype of AD by GR1 dephosphorylation, which leads to reduced HDAC2 expression. The combined findings encourage further investigations on the beneficial effects of L1 in the treatment of AD.

Mechanisms of electroacupuncture underlying treatment of osteoporosis based on HDAC2-mediated osteoblast differentiation pathway

To observe the effect of electroacupuncture (EA) on expression of histone deacetylase 2 (HDAC2), histone H3, bone formation related genes and proteins in osteoporosis rats, so as to reveal its mechanisms underlying improvement of osteoporosis. Female SD rats were randomly divided into 4 groups: sham operation, model, EA and medication (n＝ 10 rats in each group). The osteoporosis model was established by castration. EA (2 Hz, 1 mA) was applied to bilateral "Shenshu" (BL23) and "Pishu" (BL20) for 10 min, once every other day for 8 weeks. Rats of the medication group received subcutaneous injection of 17 β-estradiol (100 µg/kg, 20 µg/mL). The bone quality and quantity including the cortical bone mineral density (CBMD), trabecular bone mineral density (TBMD), ratio of bone volume /total volume (BV /TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb. Sp), trabecular bone pattern factor (Tb.Pf), and structure model index (SMI) of the right thigh-bone were detected by using a micro-computed tomography. Serum alkaline phosphatase (ALP) and estrogen 2 (E2) contents were assayed by using colorimetry and ELISA, expression levels of HDAC2, histone H3 and Runx2 in the thigh-bone were detected using Western blot, and that of Runx2 mRNA was detected using quantitative real-time PCR, separately. The co-expression of Ac-histone H3/Runx2 and Runx2/ALP was observed by using immunofluorescence histochemical staining. After modeling, the levels of TBMD, BV/TV, Tb.Th, and Tb.N, serum E2 and ALP, and expression of Runx2 protein and mRNA, Ac-histone and ALP proteins were significantly lower (P<0.01), and those of Tb.Sp, Tb.Pf and SMI, HDAC2 and histone H3 proteins were significantly higher (P<0.01) in the model group than those in the sham operation group. After the interventions, the decrease of TBMD, BV/TV, Tb.N，Runx2 protein and mRNA，ALP in both EA and medication groups, serum E2 in the medication group, and Ac-histone H3 in the EA group, and the increase of Tb.Sp in the medication group, Tb.Pf, SMI, and HDAC2 in both EA and medication groups, and histone H3 in the EA group were reversed (P<0.01, P<0.05). No significant changes were found in the levels of CBMD after modeling relevant to the sham operation group, and after EA and medication interventions (P>0.05). The effects of EA were significantly superior to 17 β-estradiol in down-regulating the expression of HDAC2 and histone H3 proteins and in up-regulating expression of Ac-histone H3 protein (P<0.01，P<0.05)．. EA treatment can increase bone density, increase bone mass and trabecular bone, and promote trabecular bone rod-like changes in plate shape in osteoporosis rats, which is related to its effect in up-regulating the expression of Ac-histone H3 protein, and down-regulating the expression of bone formation-related proteins.

Restoration of HDAC2 and Nrf2 by andrographolide overcomes corticosteroid resistance in chronic obstructive pulmonary disease.

Corticosteroid resistance poses a major barrier to an effective anti-inflammatory therapy for chronic obstructive pulmonary disease (COPD). The present study aimed to investigate potential corticosteroid re-sensitization actions of andrographolide, a bioactive molecule from the herb Andrographis paniculata, in COPD models, particularly in peripheral blood mononuclear cells (PBMCs) from COPD patients. Corticosteroid sensitivity in PBMCs collected from COPD patients, or in human monocytic U937 cells exposed to cigarette smoke extract (CSE), was determined by measuring LPS-induced IL-8 production, in the presence and absence of andrographolide. The mechanisms of corticosteroid re-sensitization action of andrographolide were evaluated in a mouse cigarette smoke (CS)-induced acute lung injury model. Impaired inhibition of IL-8 production by dexamethasone was detected in PBMCs from COPD patients and in CSE-exposed U937 cells, together with reduced levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and histone deacetylase-2 (HDAC2). In both PBMCs and CSE-exposed U937 cells, andrographolide restored dexamethasone inhibition of IL-8 production, accompanied by the up-regulation of Nrf2 and HDAC2 levels. In the U937 cells, andrographolide was able to block CSE-induced Akt and reduce the level of c-Jun. Besides, andrographolide also augmented dexamethasone actions on lowering total and neutrophil counts, cytokine levels, and oxidative damage markers in bronchoalveolar lavage fluid from CS-exposed mice. We report here for the first time a novel corticosteroid re-sensitization property of andrographolide in human PBMCs and provide mechanistic evidence to support clinical evaluation of andrographolide in reversing steroid resistance in COPD.

Abstract C109: Modulation of HDAC activity in subtypes of triple-negative breast cancer: Effects of vorinostat on HDAC 7 expression and cancer stem cells progression

Abstract Epigenetic drugs, such as histone deacetylase inhibitors (HDACi), are continuing to emerge as promising therapies for various cancers. These drugs, including FDA-approved vorinostat, are capable of multiple actions and considered to be multifunctional. Histone deacetylases (HDAC) are chromatin-modifying enzymes that are involved in various cellular events, such as tissue differentiation, autophagy, apoptosis, migration, mitosis and angiogenesis. High levels of HDACs have been detected in several cancers. Early studies in our laboratory showed different effects by vorinostat on global HDAC activity in several triple-negative breast cancer (TNBC) subtypes. This study focused on HDAC 7, which has been associated with increases in cancer stem cells and poor prognosis. Cancer stem cells play an important role in cancer resistance to therapy. Histone deacetylase inhibitors are emerging as therapy for triple-negative breast cancer, which is currently an unmet need in women's health due to the lack of targeted therapies. This study investigated the effects of vorinostat on apoptosis and the modulation of HDAC 7 expression in two subtypes of triple-negative breast cancers, MB231(MSL) and HCC70 (BL-2). Using caspase 3/7 assays vorinostat induced apoptosis. Additionally, flow cytometry and immunostaining were conducted to determine vorinostat's effects on expression of two cancer stem cell (CSC) markers, CD44 and CD24. Western blot and real-time PCR showed a significant decrease (10-fold) in the expression of HDAC 7 by vorinostat in HCC70 cells. A modest decrease (3-fold) was also observed in MB231 cells. CD44 expression was deceased by vorinostat in MB231 cells. This study demonstrated that vorinostat exerts its anticancer effects through several mechanisms, such as inducing apoptosis, downregulating HDAC 7 and decreasing cancer stem cells. This therapy could be beneficial for subtypes of TNBC, such as HCC70, an aggressive basal-like 2 cell line from an African American. Citation Format: Fatemeh Nouri Emamzadeh, Anfernee Hawkins, Gustavo Miranda-Carboni, Rhonda Moore, Beverly Word, Beverly Lyn-Cook. Modulation of HDAC activity in subtypes of triple-negative breast cancer: Effects of vorinostat on HDAC 7 expression and cancer stem cells progression [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C109.

LukS-PV Inhibits Hepatocellular Carcinoma Progression by Downregulating HDAC2 Expression

Hepatocellular carcinoma (HCC) is a common malignant tumor. LukS-PV is the S component of Panton-Valetine leukocidin (PVL), which is secreted by Staphylococcus aureus. This study investigated the effects of LukS-PV on the proliferation, apoptosis, and cell-cycle progression of HCC cells and the mechanisms of its activity. The HCC cells were treated with different LukS-PV concentrations in vitro. Cell Counting Kit-8 and 5-Ethynyl-2'-deoxyuridine (EdU) assays were used to study cell proliferation. Flow cytometry was used to measure apoptosis and cell-cycle progression. Quantitative reverse transcriptase PCR and western blot assays were used to determine mRNA and protein expression levels. Xenograft experiments were performed to determine the in vivo antitumor effect of LukS-PV. Immunostaining was performed to analyze Ki-67 and HDAC2 (histone deacetylase 2) expression. Our results showed that LukS-PV inhibited cell proliferation and induced apoptosis in a concentration-dependent manner in HCC cell lines. LukS-PV also can induce cell-cycle arrest. Moreover, we discovered that LukS-PV attenuated HDAC2 expression and upregulated PTEN; phosphorylated AKT was also reduced. Further studies demonstrated that LukS-PV treatment significantly reduced tumor growth in nude mice and suppressed Ki-67 and HDAC2 levels. Our data revealed a vital role of LukS-PV in suppressing HCC progression by downregulating HDAC2 and upregulating PTEN.

Early intervention of bone-nearby acupuncture combined with electroacupuncture on morphine tolerance in bone cancer pain rats and its effect on the expression of HDAC and MOR in dorsal root ganglia

To observe the effect of early intervention of bone-nearby acupuncture (BNA) combined with electroacupuncture (EA) on the expression of histone deacetylase1(HDAC1), histone deacetylase 2 (HDAC2) andμ-opioid recepter (MOR) in dorsal root ganglia (DRG) of bone cancer pain-morphine tolerance (BCP-MT) rats, and to explore its possible mechanism. A total of 35 SD rats were randomized into a sham BCP group (n=6), a BCP group (n=7), a MT group (n=7), a BNA+EA group (n=8) and a shame BNA group (n=7). Except of the sham BCP group, cancer cell inoculation operation at left tibia was given in the other 4 groups to establish the bone cancer pain model. In the MT group, the BNA+EA group and the shame BNA group, intraperitoneal injection of morphine hydrochloride was given to establish the morphine tolerance model. After the operation, bone-nearby acupuncture combined with electroacupuncture was applied at "Zusanli" (ST 36) and "Kunlun" (BL 60) in the BNA+EA group, with dilatational wave, 2 Hz/100 Hz in frequency, 0.5 to 1.5 mA in intensity. Intervention in the shame BNA group was applied at the same time and acupoints as those in the BNA+EA group, the needles were pierced the skin without any electrical stimulation. The needles were retained for 30 min, once a day for continuous 7 days in both BNA+EA and shame BNA groups. Before and 10, 11, 15, 22 days after the operation, the left paw withdrawal threshold (PWT) was measured in the 5 groups. The levels of HDAC1, HDAC2 and MOR in DRG were detected by Western blot. Ten days after the cancer cell inoculation operation, the PWT of the BCP, MT, BNA+EA and sham BNA groups was decreased compared with the sham BCP group (P<0.01). Eleven days after the operation, the PWT of the MT, BNA+EA and sham BNA groups was increased compared with the BCP group (P<0.01). Twenty-two days after the operation, the difference was no significant between the BCP group and MT group (P>0.05); the PWT of the BNA+EA group was increased compared with the MT and sham BNA group (P<0.01). In the BCP group, the DRG levels of HDAC1 and HDCA2 were increased, while the level of MOR was decreased compared with the sham BCP group (P<0.05, P<0.01). In the MT group, the DRG level of HDAC1 was increased compared with the BCP group (P<0.05). In the BNA+EA group, the DRG level of HDAC1 was decreased compared with the MT group and the sham BNA group (P<0.01, P<0.05), while the level of MOR was increased (P<0.01). Early intervention of bone-nearby acupuncture combined with electroacupuncture can relieve the morphine tolerance in bone cancer pain rats, it may relate to down-regulating the expression of HDAC1 and up-regulating the expression of MOR in the dorsal root ganglia.

Anti-rheumatic activity of Phenethyl isothiocyanate via inhibition of histone deacetylase-1

Rheumatoid Arthritis (RA) affects approximately 1% of the total world population. Despite incessant research and development of new therapeutic agents, management of RA is still a troublesome affair. Histone Deacetylase 1 (HDAC1) is an epigenetic regulator which play important role in pathogenesis of RA. In present study, we hypothesized that Phenethyl isothiocyanate (PEITC), a potent inhibitor of HDAC1, may ameliorate RA. Efficacy of PEITC was evaluated in Complete Freund's Adjuvant (CFA) induced arthritis model in rats. CFA (0.1 ml) was injected subplantarly in the left hind paw on day 0 to all the groups except normal control. The administration of test drug PEITC (10, 24 & 50 mg/kg) and standard drug Ibuprofen started simultaneously and was continued for 21 days. Paw edema, total arthritic index, mobility score, stair climbing ability, behavioral parameters, and bone erosion were evaluated. Further, radiographic studies, TNF-alpha as well as HDAC1 levels in synovial tissue homogenate and histological analysis were performed. Prophylactic treatment of PEITC attenuated paw edema, total arthritic index, mobility score, stair climbing ability, behavioral parameters, and bone erosion in dose dependent manner. Furthermore, there was significant decrease in TNF-alpha as well as HDAC1 levels in synovial tissue homogenate. Histological analysis revealed no cartilage damage, bone erosion, hyperplasia at synovial lining as well as infiltration of inflammatory cells in treatment group. Results of this study suggest potent anti-rheumatoid arthritis activity of Phenethyl isothiocyanate in CFA induced RA model in rats.

ATP depletion induced cochlear hair cells death through histone deacetylation in vitro

Previous studies have shown histone modifications being present in cochlear hair cells in animal models of hearing loss. Our past studies have shown that ATP depletion, histone deacetylase (HDAC) upregulation, and histone deacetylation occur in cochlea after noise exposure, and these are linked to hair cell death. Whether ATP depletion correlates with the expression level of HDACs and acetylation of histones is still unknown. In this study, we investigated the changes in the expression of HDACs and the level of histone acetylation in cochlear hair cells using an ATP-depleted explant culture of mouse organ of Corti. We found that the expression of HDAC3 and HDAC6 increased and hair cells were lost after oligomycin A (OA) treatment. Meanwhile, the acetylation level of histone H2B reduced. However, when oligomycin was combined with an HDAC inhibitor, trichostatin A (TSA), the acetylation level of histone H3 was restored. Moreover, combined treatment of oligomycin and TSA or sodium butyrate (NaB) attenuated oligomycin-induced cochlear hair cell loss. In conclusion, our results indicated that ATP depletion led to histone deacetylation and eventually resulted in hair cell death.

Histone deacetylases 1 and 2 restrain CD4+ cytotoxic T lymphocyte differentiation.

Some effector CD4+ T cell subsets display cytotoxic activity, thus breaking the functional dichotomy of CD4+ helper and CD8+ cytotoxic T lymphocytes. However, molecular mechanisms regulating CD4+ cytotoxic T lymphocyte (CD4+ CTL) differentiation are poorly understood. Here we show that levels of histone deacetylases 1 and 2 (HDAC1-HDAC2) are key determinants of CD4+ CTL differentiation. Deletions of both Hdac1 and 1 Hdac2 alleles (HDAC1cKO-HDAC2HET) in CD4+ T cells induced a T helper cytotoxic program that was controlled by IFN-γ–JAK1/2–STAT1 signaling. In vitro, activated HDAC1cKO-HDAC2HET CD4+ T cells acquired cytolytic activity and displayed enrichment of gene signatures characteristic of effector CD8+ T cells and human CD4+ CTLs. In vivo, murine cytomegalovirus–infected HDAC1cKO-HDAC2HET mice displayed a stronger induction of CD4+ CTL features compared with infected WT mice. Finally, murine and human CD4+ T cells treated with short-chain fatty acids, which are commensal-produced metabolites acting as HDAC inhibitors, upregulated CTL genes. Our data demonstrate that HDAC1-HDAC2 restrain CD4+ CTL differentiation. Thus, HDAC1-HDAC2 might be targets for the therapeutic induction of CD4+ CTLs.

Inhibition of Amyloid-Beta Production, Associated Neuroinflammation, and Histone Deacetylase 2-Mediated Epigenetic Modifications Prevent Neuropathology in Alzheimer's Disease in vitro Model.

Alzheimer’s disease (AD) is a growing global threat to healthcare in the aging population. In the USA alone, it is estimated that one in nine persons over the age of 65 years is living with AD. The pathology is marked by the accumulation of amyloid-beta (Aβ) deposition in the brain, which is further enhanced by the neuroinflammatory process. Nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) are the major neuroinflammatory pathways that intensify AD pathogenesis. Histone deacetylase 2 (HDAC2)-mediated epigenetic mechanisms play a major role in the genesis and neuropathology of AD. Therefore, therapeutic drugs, which can target Aβ production, NLRP3 activation, and HDAC2 levels, may play a major role in reducing Aβ levels and the prevention of associated neuropathology of AD. In this study, we demonstrate that withaferin A (WA), an extract from Withania somnifera plant, significantly inhibits the Aβ production and NF-κB associated neuroinflammatory molecules’ gene expression. Furthermore, we demonstrate that cytokine release inhibitory drug 3 (CRID3), an inhibitor of NLRP3, significantly prevents inflammasome-mediated gene expression in our in vitro AD model system. We have also observed that mithramycin A (MTM), an HDAC2 inhibitor, significantly upregulated the synaptic plasticity gene expression and downregulated HDAC2 in SH-SY5Y cells overexpressing amyloid precursor protein (SH-APP cells). Therefore, the introduction of these agents targeting Aβ production, NLRP3-mediated neuroinflammation, and HDAC2 levels will have a translational significance in the prevention of neuroinflammation and associated neurodegeneration in AD patients.