Insulin-dependent transcriptional control in L6 rat myotubes is associated with modulation of histone acetylation and accumulation of the histone variant H2A.Z in the proximity of the transcriptional start site

2014 ◽  
Vol 92 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Ouafa Zerzaihi ◽  
Sabrina Chriett ◽  
Hubert Vidal ◽  
Luciano Pirola

Besides its direct metabolic effects, insulin induces transcriptional alterations in its target tissues. However, whether such changes are accompanied by epigenetic changes on the chromatin template encompassing insulin responsive genes is unclear. Here, mRNA levels of insulin-responsive genes hexokinase 2 (Hk2), insulin receptor substrate (Irs2), and the PI3K subunit p85β (Pik3r2) were compared in control versus insulin-stimulated L6 myotubes. Chromatin immunoprecipitation (ChIP) was performed with antibodies directed to histone H2A, histone variant H2A.Z, acetylated histone H3 on lysines 9/14, and acetylated H2A.Z. Insulin induced a more than 2-fold Hk2 mRNA increase, while Irs2 and Pik3r2 were downregulated. ChIP to H2A and H2A.Z showed higher H2A.Z accumulation around the transcriptional start site (TSS) of these insulin-modulated genes, while H2A.Z accumulation was lower distally to the TSS in the Hk2 promoter. H2A.Z levels and H3K9/14 acetylation correlated on several loci along the Hk2 gene, and H3K9/14 as well as H2A.Z acetylation was enhanced by insulin treatment. On the contrary, reduced H3K9/14 acetylation was observed in insulin-repressed Irs2 and Pik3r2, and recovery of acetylation by treatment with the histone deacetylase inhibitor trichostatin A reverted insulin-induced Irs2 downregulation. The chromatin regions encompassing selected insulin-responsive genes are thus featured by accumulation of H2A.Z around the TSS. H2A.Z accumulation facilitates insulin-dependent modulation of pharmacologically treatable H3K9/14 and H2A.Z acetylations. Indeed, inhibition of histone deacetylases by TSA treatment reverted insulin induced Irs2 gene downregulation. Dysregulated histone acetylation may thus be potentially targeted with histone deacetylase inhibitors.

2005 ◽  
Vol 185 (3) ◽  
pp. 539-549 ◽  
Author(s):  
Andrei G Gunin ◽  
Irina N Kapitova ◽  
Nina V Suslonova

It is suggested that estrogen hormones recruit mechanisms controlling histone acetylation to bring about their effects in the uterus. However, it is not known how the level of histone acetylation affects estrogen-dependent processes in the uterus, especially proliferation and morphogenetic changes. Therefore, this study examined the effects of histone deacetylase blockers, trichostatin A and sodium butyrate, on proliferative and morphogenetic reactions in the uterus under long-term estrogen treatment. Ovari-ectomized mice were treated with estradiol dipropionate (4 μg per 100 g; s.c., once a week) or vehicle and trichostatin A (0.008 mg per 100 g; s.c., once a day) or sodium butyrate (1% in drinking water), or with no additional treatments for a month. In animals treated with estradiol and trichostatin A or sodium butyrate, uterine mass was increased, and abnormal uterine glands and atypical endometrial hyperplasia were found more often. Both histone deacetylase inhibitors produced an increase in the numbers of mitotic and bromodeoxyuridine-labelled cells in luminal and glandular epithelia, in stromal and myometrial cells. Levels of estrogen receptor-α and progesterone receptors in uterine epithelia, stromal and myometrial cells were decreased in mice treated with estradiol and trichostatin A or sodium butyrate. Expression of β-catenin in luminal and glandular epithelia was attenuated in mice treated with estradiol with trichostatin A or sodium butyrate. Both histone deacetylase inhibitors have similar unilateral effects; however the action of trichostatin A was more expressed than that of sodium butyrate. Thus, histone deacetylase inhibitors exert proliferative and morphogenetic effects of estradiol. The effects of trichostatin A and sodium butyrate are associated with changes in expression of estrogen receptor-α, progesterone receptors and β-catenin in the uterus.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1164
Author(s):  
Óscar Martínez ◽  
Verónica Arjones ◽  
María Victoria González ◽  
Manuel Rey

The low induction rates of somatic embryogenesis are one of the main limitations in its routine application in the grapevine (Vitis vinifera L.). The use of an induction medium containing histone deacetylase inhibitors (trichostatin A and, mainly, sodium butyrate) resulted in an improvement of the embryogenic responses in grapevine (cv. Mencía) cotyledonary and recently germinated somatic embryos. The relative expression of several grapevine genes related to embryogenic competence or encoding histone deacetylase enzymes was studied in cotyledonary somatic embryos that were cultured in the presence of 0.5 mM sodium butyrate. The results showed a significant overexpression of the BBM and VvSERK2 genes after 24 h of culture, whereas the VvWOX2 gene was underexpressed less in treated versus untreated explants. The results suggest that the inhibitor may trigger a molecular response related to an increase in embryogenic competence and changes in the expression of associated genes. The treatment with sodium butyrate also produced significant variations in the expression of several histone deacetylase enzyme-encoding genes. These results may enhance the possibility of obtaining somatic embryos, reducing the seasonal constraints associated with the use of floral explants in grapevines.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yu Mao ◽  
Jing Zhou ◽  
Xuesheng Liu ◽  
Erwei Gu ◽  
Zhi Zhang ◽  
...  

Histone deacetylase inhibitors (HDACIs), which interfere with the epigenetic process of histone acetylation, have shown analgesic effects in animal models of persistent pain. The HDAC family comprises 18 genes; however, the different effects of distinct classes of HDACIs on pain relief remain unclear. The aim of this study was to determine the efficacy of these HDACIs on attenuating thermal hyperalgesia in persistent inflammatory pain. Persistent inflammatory pain was induced by injecting Complete Freund’s Adjuvant (CFA) into the left hind paw of rats. Then, HDACIs targeting class I (entinostat (MS-275)) and class IIa (sodium butyrate, valproic acid (VPA), and 4-phenylbutyric acid (4-PBA)), or class II (suberoylanilide hydoxamic acid (SAHA), trichostatin A (TSA), and dacinostat (LAQ824)) were administered intraperitoneally once daily for 3 or 4 days. We found that the injection of SAHA once a day for 3 days significantly attenuated CFA-induced thermal hyperalgesia from day 4 and lasted 7 days. In comparison with SAHA, suppression of hyperalgesia by 4-PBA peaked on day 2, whereas that by MS-275 occurred on days 5 and 6. Fatigue was a serious side effect seen with MS-275. These findings will be beneficial for optimizing the selection of specific HDACIs in medical fields such as pain medicine and neuropsychiatry.


2005 ◽  
Vol 25 (5) ◽  
pp. 1608-1619 ◽  
Author(s):  
Hong Duan ◽  
Caroline A. Heckman ◽  
Linda M. Boxer

ABSTRACT Histone deacetylase (HDAC) inhibitors are promising antitumor agents, but they have not been extensively explored in B-cell lymphomas. Many of these lymphomas have the t(14;18) translocation, which results in increased bcl-2 expression and resistance to apoptosis. In this study, we examined the effects of two structurally different HDAC inhibitors, trichostatin A (TSA) and sodium butyrate (NaB), on the cell cycle, apoptosis, and bcl-2 expression in t(14;18) lymphoma cells. We found that in addition to potent cell cycle arrest, TSA and NaB also dramatically induced apoptosis and down-regulated bcl-2 expression, and overexpression of bcl-2 inhibited TSA-induced apoptosis. The repression of bcl-2 by TSA occurred at the transcriptional level. Western blot analysis and quantitative chromatin immunoprecipitation (ChIP) assay showed that even though HDAC inhibitors increased overall acetylation of histones, localized histone H3 deacetylation occurred at both bcl-2 promoters. TSA treatment increased the acetylation of the transcription factors Sp1 and C/EBPα and decreased their binding as well as the binding of CBP and HDAC2 to the bcl-2 promoters. Mutation of Sp1 and C/EBPα binding sites reduced the TSA-induced repression of bcl-2 promoter activity. This study provides a mechanistic rationale for the use of HDAC inhibitors in the treatment of human t(14;18) lymphomas.


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