Effect of histone acetylation modification with sodium butyrate, a histone deacetylase inhibitor, on cell cycle, apoptosis, ploidy and gene expression in porcine fetal fibroblasts

Butyrate restores the fat/lean mass ratio balance and energy metabolism and reinforces the tight junction-mediated intestinal epithelial barrier in prediabetic mice independently of its anti-inflammatory and epigenetic actions

Tissue/cellular actions of butyrate on energy metabolism and intestinal barrier in normal metabolic conditions or prediabetes are still unclear. In this work, we investigated the beneficial effect of dietary supplementation with sodium butyrate on energy metabolism, body mass composition, and intestinal epithelial barrier mediated by tight junction (TJ) in chow diet-fed normal and high-fat diet (HF)-fed prediabetic mice, considering the well-known butyrate action as an epigenetic and inflammatory regulator. Butyrate significantly reduced the fat/lean mass ratio, slightly ameliorated dyslipidemia, restored oral glucose tolerance, and increased basal energy expenditure in prediabetic HF-fed mice but had no effect on control animals. Such effects were observed in the absence of significant alterations in the hypothalamic expression of orexigenic and anorexigenic genes and motor activity. Also, butyrate suppressed the whitening effect of HF on brown adipose tissue but did not affect cell bioenergetics in immortalized UCP1-positive adipocytes in vitro. Butyrate reinforced the intestinal epithelial barrier in HF-fed mice and in Caco-2 monolayers, which involved higher trafficking of TJ proteins to the cell-cell contact region of the intestinal epithelia, without affecting TJ gene expression or the acetylation level of histones H3 and H4 in vivo. All metabolic and intestinal effects of butyrate in prediabetic mice occurred in the absence of detectable changes in systemic or local inflammation, or alterations in endotoxemia markers. Butyrate has no effect on chow diet-fed mice but, in the context of HF-induced prediabetes, it prevents metabolic and intestinal dysfunctions independently of its anti-inflammatory and epigenetic actions.

Enhancement of Chromatin and Epigenetic Reprogramming in Porcine SCNT Embryos—Progresses and Perspectives

Over the last 25 years, cloned animals have been produced by transferring somatic cell nuclei into enucleated oocytes (SCNT) in more than 20 mammalian species. Among domestic animals, pigs are likely the leading species in the number of clones produced by SCNT. The greater interest in pig cloning has two main reasons, its relevance for food production and as its use as a suitable model in biomedical applications. Recognized progress in animal cloning has been attained over time, but the overall efficiency of SCNT in pigs remains very low, based on the rate of healthy, live born piglets following embryo transfer. Accumulating evidence from studies in mice and other species indicate that new strategies for promoting chromatin and epigenetic reprogramming may represent the beginning of a new era for pig cloning.

GPR43 regulates sodium butyrate-induced angiogenesis and matrix remodeling

Butyrate is a short-chain fatty acid (SCFA) derived from microbiota and is involved in a range of cell processes in a concentration-dependent manner. Low concentrations of sodium butyrate (NaBu) were shown to be proangiogenic. However, the mechanisms associated with these effects are not yet fully known. Here, we investigated the contribution of the SCFA receptor GPR43 in the proangiogenic effects of local treatment with NaBu and its effects on matrix remodeling using the sponge-induced fibrovascular tissue model in mice lacking the Gpr43 gene (Gpr43-KO) and the wild-type (WT) mice. We demonstrated that NaBu (0.2 mM intraimplant) treatment enhanced the neovascularization process, blood flow, and VEGF levels in a GPR43-dependent manner in the implants. Moreover, NaBu was able to modulate matrix remodeling aspects of the granulation tissue such as proteoglycan production, collagen deposition, and α-smooth muscle actin (α-SMA) expression in vivo, besides increasing transforming growth factor (TGF)-β1 levels in the fibrovascular tissue, in a GPR43-dependent manner. Interestingly, NaBu directly stimulated L929 murine fibroblast migration and TGF-β1 and collagen production in vitro. GPR43 was found to be expressed in human dermal fibroblasts, myofibroblasts, and endothelial cells. Overall, our findings evidence that the metabolite-sensing receptor GPR43 contributes to the effects of low dose of NaBu in inducing angiogenesis and matrix remodeling during granulation tissue formation. These data provide important insights for the proposition of new therapeutic approaches based on NaBu, beyond the highly explored intestinal, anti-inflammatory, and anticancer purposes, as a local treatment to improve tissue repair, particularly, by modulating granulation tissue components.NEW & NOTEWORTHY Our data show the contribution of the metabolite-sensing receptor GPR43 in the effects of low dose of sodium butyrate (NaBu) on stimulating angiogenesis and extracellular matrix remodeling in a model of granulation tissue formation in mice. We also show that human dermal fibroblasts, myofibroblasts, and endothelial cells express the receptor GPR43. These data provide important insights for the use of NaBu in local therapeutic approaches applicable to tissue repair in sites other than the intestine.

The negative role of histone acetylation in cobalt chloride-induced neurodegenerative damages in SHSY5Y cells

Cobalt has been known for its neurotoxicity in numerous studies. However, the molecular mechanism underlying cobalt-induced neurotoxicity remains largely unknown. In this study, two neuroblastoma (SHSY5Y and N2a) cell lines and a phaeochromocytoma (PC12) line were used as in vitro models. Cells were treated for 24 h with 50, 100, 200, 300, 400 µM cobalt chloride (CoCl₂) or cultured with 300 μM CoCl₂ for 4, 8, 12 and 24 h to investigate the effects of histone acetylation on CoCl₂-induced neurodegenerative damages. Our findings demonstrate that CoCl₂ suppresses the acetylation of histone H3 and H4 in a time-dependent and dosage-dependent manner. Furthermore, CoCl₂ selectively decreases the expression and activity of histone acetyltransferase (HAT) but has no effects on histone deacetylase (HDAC) in SHSY5Y cells. More importantly, we show that 100 ng/mL HDAC inhibitor trichostatin (TSA) pre-treatment partly attenuates 300 μM CoCl₂-induced neurodegenerative damages in SHSY5Y cells. Mechanistic analyses show that CoCl₂-induced neurodegenerative damages are associated with the dysfunction of APP, BACE1, PSEN1, NEP and HIF-1α genes, whose expression are partly mediated by histone modification. In summary, we demonstrate that histone acetylation is involved in CoCl₂-induced neurodegenerative damages. Our study indicates an important connection between histone modification and the pathological process of neurodegenerative damages and provides a mechanism for cobalt-mediated epigenetic regulation.

Histone hyperacetylation may improve the preimplantation development and epigenetic status of cloned embryos

The current study investigated the mechanism of mini pig fetal fibroblasts in improving the epigenetic modification and preimplantation development of cloned embryos. The results showed that the increased AcH3K14 level was dose- and time-dependent. Histone hyperacetylation had no significant effect on cell morphology, cell viability, cell cycle, and relative gene (HDAC1, HAT1, DNMT3A, and BAX) expression. The treated cloned embryos had significantly higher development rates and the total nuclei number than the control (27.62 ± 6.94 % vs. 16.14 ± 10.55 %; 43.90 ± 18.39 vs. 33.06 ± 15.87; P < 0.05). The AcH3K14 level in the treated cloned blastocysts was close to that of IVF blastocysts (5.17 ± 0.93 vs. 5.45 ± 1.91, P > 0.05). The gene transcription (CDX2 and OCT4) of the treated cloned blastocysts was significantly up-regulated than the control (3.32 ± 0.51 vs. 2.05 ± 0.30; 1.21 ± 0.18 vs. 0.81 ± 0.09; P < 0.05). The improvement in the cloned embryo development and the partial correction of abnormal acetylation modification were not necessarily related to the cellular characteristics. This could be caused by histone hyperacetylation of mini pig fetal fibroblasts.

Combination therapy with butyrate and docosahexaenoic acid for keloid fibrogenesis: an in vitro study

Background:

A single, effective therapeutic regimen for keloids has not been established yet, and the development of novel therapeutic approaches is expected. Butyrate, a short-chain fatty acid, and docosahexaenoic acid (DHA), a ω-3 polyunsaturated fatty acid, play multiple anti-inflammatory and anticancer roles via their respective mechanisms of action.

Objective:

In this study, we evaluated the antifibrogenic effects of their single and combined use on keloid fibroblasts.

Methods:

Keloid fibroblasts were treated with butyrate (0-16 mM) and/or DHA (0-100 µM) for 48 or 96 h.

Results:

Butyrate inhibited cell proliferation, and α-smooth muscle actin (α-SMA) and type III collagen expressions, with inhibition of the transforming growth factor (TGF)-β1 and TGF-β type I receptor expressions and increased prostaglandin E2 with upregulation of cyclooxygenase-1 expression with induction of histone acetylation. DHA inhibited α-SMA, type III collagen, and TGF-β type I receptor expressions. Then, the butyrate/DHA combination augmented the antifibrogenic effects, resulting in additional inhibition of α-SMA, type I and III collagen expressions, with strong disruption of stress fiber and apoptosis induction. Moreover, the butyrate/DHA combination inhibited the cyclooxygenase-2 expression, suggesting stronger anti-inflammatory effect than each monotherapy.

Study limitations:

Activation in keloid tissue is affected not only by fibroblasts but also by epithelial cells and immune cells. Evaluation of the effects by butyrate and DHA in these cells or in an in vivo study is required.

Conclusion:

This study demonstrated that butyrate and docosahexaenoic acid have antifibrogenic effects on keloid fibroblasts and that these may exert therapeutic effects for keloid.

Butyrate reduces high-fat diet-induced metabolic alterations, hepatic steatosis and pancreatic beta cell and intestinal barrier dysfunctions in prediabetic mice

In this study, we investigated the effect of diet supplementation with sodium butyrate (5% w/w), a short-chain fatty acid produced by the intestinal microbiota, on metabolic parameters, body adiposity, hepatic and pancreatic lipid accumulation, beta cell function/mass as well as on the structure and function of the tight junction-mediated intestinal epithelial barrier in both normal and obese/prediabetic C57 mice fed a regular (control) or high-fat diet for 60 days, respectively. Butyrate treatment significantly inhibited all the high-fat-induced metabolic dysfunctions evaluated, i.e. significantly reduced the weight gain and body adiposity as well as the insulin resistant state, hyperglycemia and hyperinsulinemia, without changing food intake. In addition, high-fat-fed mice treated with this short-chain fatty acid displayed no compensatory hyperplasia of pancreatic beta cells nor marked hepatic steatosis as seen in prediabetic mice after high-fat diet only. Isolated pancreatic islets from high-fat-fed mice treated with butyrate showed improvement of the insulin secretion, which was associated with a significant decrease in lipid accumulation within the pancreas. Butyrate enhanced the intestinal epithelial barrier, as revealed by the FITC-Dextran permeability assay, which was accompanied by a significant increase in the junctional content of the tight junction-associated claudin-1 in intestinal epithelia of jejunum, ileum, and colon of both control and high-fat mice. In conclusion, our results showed that diet supplementation with butyrate inhibits the deleterious effects of high-fat diet intake on metabolic parameters and structure/function of several tissues/organs associated with type 2 diabetes mellitus in a mouse model, suggesting a potential use of this short-chain fatty acid in the treatment of this endocrine-metabolic disorder. Impact statement Butyrate is a short-chain fatty acid produced by the intestinal microbiota through the fermentation of non-absorbable carbohydrates and proteins (e.g. fibers). Sodium butyrate incorporated into the diet displayed a protective action on metabolic, hepatic, pancreatic and intestinal alterations induced by high-fat diet in mice, resulting in significant inhibition of the development of a prediabetic state. Thus, our data suggest that butyrate may have a potential therapeutic use in the treatment of type 2 diabetes and related disorders.

Window-of-Opportunity Study of Valproic Acid in Breast Cancer Testing a Gene Expression Biomarker

Purpose

The anticancer activity of valproic acid (VPA) is attributed to the inhibition of histone deacetylase. We previously published the genomically derived sensitivity signature for VPA (GDSS-VPA), a gene expression biomarker that predicts breast cancer sensitivity to VPA in vitro and in vivo. We conducted a window-of-opportunity study that examined the tolerability of VPA and the ability of the GDSS-VPA to predict biologic changes in breast tumors after treatment with VPA.

Patients and Methods

Eligible women had untreated breast cancer with breast tumors larger than 1.5 cm. After a biopsy, women were given VPA for 7 to 12 days, increasing from 30 mg/kg/d orally divided into two doses per day to a maximum of 50 mg/kg/d. After VPA treatment, serum VPA level was measured and then breast surgery or biopsy was performed. Tumor proliferation was assessed by using Ki-67 immunohistochemistry. Histone acetylation of peripheral blood mononuclear cells was assessed by Western blot. Dynamic contrast-enhanced magnetic resonance imaging scans were performed before and after VPA treatment.

Results

Thirty women were evaluable. The median age was 54 years (range, 31-73 years). Fifty-two percent of women tolerated VPA at 50 mg/kg/d, but 10% missed more than two doses as a result of adverse events. Grade 3 adverse events included vomiting and diarrhea (one patient) and fatigue (one patient). The end serum VPA level correlated with a change in histone acetylation of peripheral blood mononuclear cells (ρ = 0.451; P = .024). Fifty percent of women (three of six) with triple-negative breast cancer had a Ki-67 reduction of at least 10% compared with 17% of other women. Women whose tumors had higher GDSS-VPA were more likely to have a Ki-67 decrease of at least 10% (area under the curve, 0.66).

Conclusion

VPA was well tolerated and there was a significant correlation between serum VPA levels and histone acetylation. VPA treatment caused a decrease in proliferation of breast tumors. The genomic biomarker correlated with decreased proliferation. Inhibition of histone deacetylase is a valid strategy for drug development in triple-negative breast cancer using gene expression biomarkers.

Engineering Recombinant Protein Sensors for Quantifying Histone Acetylation

H3K14ac (acetylation of lysine 14 of histone H3) is one of the most important epigentic modifications. Aberrant changes in H3K14ac have been associated with various diseases, including cancers and neurological disorders. Tools that enable detection and quantification of H3K14ac levels in cell extracts and in situ are thus of critical importance to reveal its role in various biological processes. Current detection techniques of specific histone modifications, however, are constrained by tedious sample pretreatments, lack of quantitative accuracy, and reliance on high quality antibodies. To address this issue, we engineered recombinant sensors that are suitable for probing histone acetylation levels using various biological samples. The protein sensor contains recongition domain(s) with sequences derived from the bromodomain of human polybromo-1 (PB1), a natural H3K14ac reader domain. Various sensor designs were tested using nuclear extracts and live cells. The sensor containing dimeric repeats of bromodomain was found most effective in quantifying H3K14ac level in both in vitro and in situ assays. The sensor has a linear detection range of 0.5-50 nM when mixed with nuclear extracts. The sensor colocalizes with H3K14ac antibodies in situ when transfected into human embryonic kidney 293T (HEK293T) cells and is thus capable of providing spatial details of histone modification within the nucleus. Corrected nuclear fluorescence intensity was used to quantify the modification level in situ and found to correlate well with our in vitro assays. Our sensor offers a novel tool to characterize the histone modification level using nuclear extracts and probe histone modification change in live cells.

Effects of Sodium Butyrate Treatment on Histone Modifications and the Expression of Genes Related to Epigenetic Regulatory Mechanisms and Immune Response in European Sea Bass (Dicentrarchus Labrax) Fed a Plant-Based Diet

Bacteria that inhabit the epithelium of the animals' digestive tract provide the essential biochemical pathways for fermenting otherwise indigestible dietary fibers, leading to the production of short-chain fatty acids (SCFAs). Of the major SCFAs, butyrate has received particular attention due to its numerous positive effects on the health of the intestinal tract and peripheral tissues. The mechanisms of action of this four-carbon chain organic acid are different; many of these are related to its potent regulatory effect on gene expression since butyrate is a histone deacetylase inhibitor that play a predominant role in the epigenetic regulation of gene expression and cell function. In the present work, we investigated in the European sea bass (Dicentrarchus labrax) the effects of butyrate used as a feed additive on fish epigenetics as well as its regulatory role in mucosal protection and immune homeostasis through impact on gene expression. Seven target genes related to inflammatory response and reinforcement of the epithelial defense barrier [tnfα (tumor necrosis factor alpha) il1β, (interleukin 1beta), il-6, il-8, il-10, and muc2 (mucin 2)] and five target genes related to epigenetic modifications [dicer1(double-stranded RNA-specific endoribonuclease), ehmt2 (euchromatic histone-lysine-N-methyltransferase 2), pcgf2 (polycomb group ring finger 2), hdac11 (histone deacetylase-11), and jarid2a (jumonji)] were analyzed in fish intestine and liver. We also investigated the effect of dietary butyrate supplementation on histone acetylation, by performing an immunoblotting analysis on liver core histone extracts. Results of the eight-week-long feeding trial showed no significant differences in weight gain or SGR (specific growth rate) of sea bass that received 0.2% sodium butyrate supplementation in the diet in comparison to control fish that received a diet without Na-butyrate. Dietary butyrate led to a twofold increase in the acetylation level of histone H4 at lysine 8, but showed no effect on the histone H3 at Lys9. Moreover, two different isoforms of histone H3 that might correspond to the H3.1 and H3.2 isoforms previously found in terrestrial animals were separated on the immunoblots. The expression of four (il1 β, il8, irf1, and tnfα) out of seven analyzed genes related to mucosal protection and inflammatory response was significantly different between the two analyzed tissues but only il10 showed differences in expression due to the interaction between tissue and butyrate treatment. In addition, butyrate caused significant changes in vivo in the expression of genes related to epigenetic regulatory mechanisms such as hdac11, ehmt2, and dicer1. Statistical analysis by two-way ANOVA for these genes showed not only significant differences due to the butyrate treatment, but also due to the interaction between tissue and treatment.

Gut ecosystem: how microbes help us

The human gut houses one of the most complex and abundant ecosystems composed of up to 1013-1014 microorganisms. Although the anthropocentric concept of life has concealed the function of microorganisms inside us, the important role of gut bacterial community in human health is well recognised today. Moreover, different microorganims, which are commonly present in a large diversity of food products, transit through our gut every day adding in some cases a beneficial effect to our health (probiotics). This crosstalk is concentrated mainly in the intestinal epithelium, where microbes provide the host with essential nutrients and modulation of the immune system. Furthermore, microorganisms also display antimicrobial activities maintaining a gut ecosystem stable. This review summarises some of the recent findings on the interaction of both commensal and probiotic bacteria with each other and with the host. The aim is to highlight the cooperative status found in healthy individuals as well as the importance of this crosstalk in the maintenance of human homeostasis.

Sodium butyrate-induced histone hyperacetylation up-regulating WT1 expression in porcine kidney fibroblasts

OBJECTIVES

Wilms' tumor 1 gene (WT1) is essential for the development of kidney and histone acetylation and is involved in its expression regulation in mice. However, whether WT1 expression is associated with histone acetylation in porcine kidney cells is unclear. Here, the effect of histone deacetylase inhibitor sodium butyrate (NaBu)-induced hyperacetylation on WT1 expression in porcine kidney fibroblasts (PKF) was examined.

RESULTS

Treatments of NaBu (1, 3, 6 mM) for 24 h increased PKF viability, and 24, 48 h-treatments of 1 mM NaBu enhanced PKF proliferation. WT1 mRNA levels were significantly elevated in NaBu-treated (1, 3 mM for 24, 48 h, respectively) PKF samples. Consistently, strengthened expression of WT1 protein and histone acetylation level were detected in NaBu-treated PKF cells.

CONCLUSION

Together, NaBu-induced hyperacetylation up-regulates WT1 expression in PKF, suggesting the involvement of histone acetylation in the transcriptional modulation of WT1 in porcine kidney cells.

ZBP-89 reduces histone deacetylase 3 by degrading IkappaB in the presence of Pin1

BACKGROUND

Histone deacetylase 3 (HDAC3) is overexpressed in cancers and its inhibition enhances anti-tumor chemotherapy. ZBP-89, a transcription factor, can induce pro-apoptotic Bak and reduce HDAC3 but the mechanism is unknown. Pin1, a molecular switch that determines the fate of phosphoproteins, is known to interact with HDAC3. The aim of this study was to investigate the mechanism how ZBP-89 downregulated HDAC3.

METHODS

In this study, liver cells, Pin1-knockout Pin1(-/-) and Pin1 wild-typed Pin(+/+) cells were used to explore how ZBP-89 reduced HDAC3. The overexpression of ZBP-89 was achieved by infecting cells with Ad-ZBP-89, an adenoviral construct containing ZBP-89 gene. The role of NF-κB was determined using CAY10576, MG132 and SN50, the former two being inhibitors of IκB degradation and SN50 being an inhibitor of p65/p50 translocation. A xenograft tumor model was used to confirm the in vitro data.

RESULTS

ZBP-89 reduced HDAC3, and it could form a complex with IκB and induce IκB phosphorylation to inhibit IκB. Furthermore, ZBP-89-mediated HDAC3 reduction was suppressed by IκB degradation inhibitors CAY10576 and MG132 but not by p65/p50 translocation inhibitor SN50, indicating that IκB decrease rather than the elevated activity of NF-κB contributed to HDAC3 reduction. ZBP-89-mediated HDAC3 or IκB reduction was significantly less obvious in Pin1(-/-) cells compared with Pin1(+/+) cells. In Ad-ZBP-89-infected Pin1(+/+) cancer cells, Pin1 siRNA increased HDAC3 but decreased Bak, compared with cells without ZBP-89 infection. These findings indicate that Pin1 participates in ZBP-89-mediated HDAC3 downregulation and Bak upregulation. The cell culture result was confirmed by in vivo mouse tumor model experiments.

CONCLUSIONS

ZBP-89 attenuates HDAC3 by increasing IκB degradation. Such attenuation is independent of NF-κB activity but partially depends on Pin1. The novel pathway identified may help generate new anti-cancer strategy by targeting HDAC3 and its related molecules.

Sodium butyrate promotes the differentiation of rat bone marrow mesenchymal stem cells to smooth muscle cells through histone acetylation

Establishing an effective method to improve stem cell differentiation is crucial in stem cell transplantation. Here we aimed to explore whether and how sodium butyrate (NaB) induces rat bone marrow mesenchymal stem cells (MSCs) to differentiate into bladder smooth muscle cells (SMCs). We found that NaB significantly suppressed MSC proliferation and promoted MSCs differentiation into SMCs, as evidenced by the enhanced expression of SMC specific genes in the MSCs. Co-culturing the MSCs with SMCs in a transwell system promoted the differentiation of MSCs into SMCs. NaB again promoted MSC differentiation in this system. Furthermore, NaB enhanced the acetylation of SMC gene-associated H3K9 and H4, and decreased the expression of HDAC2 and down-regulated the recruitment of HDAC2 to the promoter regions of SMC specific genes. Finally, we found that NaB significantly promoted MSC depolarization and increased the intracellular calcium level of MSCs upon carbachol stimulation. These results demonstrated that NaB effectively promotes MSC differentiation into SMCs, possibly by the marked inhibition of HDAC2 expression and disassociation of HDAC2 recruitment to SMC specific genes in MSCs, which further induces high levels of H3K9ace and H4ace and the enhanced expression of target genes, and this strategy could potentially be applied in clinical tissue engineering and cell transplantation.

Sodium butyrate improves the cloned yak embryo viability and corrects gene expression patterns

Interspecies somatic cell nuclear transfer (iSCNT), a powerful tool in basic scientific research, has been used widely to increase and preserve the population of endangered species. Yak (Bos grunniens) is one of these species. Development to term of interspecies cloned yak embryos has not been achieved, possibly due to abnormal epigenetic reprogramming. Previous studies have demonstrated that treatment of intraspecies cloned embryos with (NaBu) significantly improves nuclear–cytoplasmic reprogramming and viability in vitro. Therefore, in this study, we evaluated the effect of optimal NaBu concentration and exposure time on preimplantation development of yak iSCNT embryos and on the expression patterns of developmentally important genes. The results showed that 8-cell rate, blastocyst formation rate and total cell number increased significantly compared with their untreated counterparts when yak iSCNT embryos were treated with 5 nM NaBu for 12 h after activation, but that the 2-cell stage embryo rate was not significantly different. The treatment of NaBu also increased significantly the expression levels of Oct-4 and decreased the expression levels of HDAC-2, Dnmt-1 and IGF-1; the expression patterns of these genes were more similar to that of their bovine–yak in vitro fertilization (BY-IVF) counterparts. The results described above indicated that NaBu treatment improved developmental competence in vitro and ‘corrected’ the gene expression patterns of yak iSCNT embryos.

Short-chain fatty acids suppress lipopolysaccharide-induced production of nitric oxide and proinflammatory cytokines through inhibition of NF-κB pathway in RAW264.7 cells

Short-chain fatty acids (SCFAs) produced by the colonic bacterial fermentation of dietary fiber contribute a significant proportion of daily energy requirement. Furthermore, these compounds are modulators of macrophage function and potential targets for the development of new drugs. The aims of this study were to evaluate the effects of three types of SCFAs (sodium acetate (NaAc), sodium propionate (NaP), and sodium butyrate (NaB)) on the production of NO and inducible nitric oxide synthase (iNOS) and proinflammatory and antiinflammatory cytokines (tumor necrosis factor-α (TNF-α) and interleukin (IL-1, IL-6, and IL-10)) and to observe the effect of NaAc on inhibiting lipopolysaccharide (LPS)-induced NF-κB activation in LPS-stimulated RAW264.7 cells. The results show that three types of SCFAs (acetate, propionate, and butyrate) reduced the production of proinflammatory factors, including TNF-α, IL-1β, IL-6, and NO, and inhibited the vitality of iNOS. Meanwhile, SCFAs enhanced the production of antiinflammatory cytokine IL-10 in lower concentrations (1-1,200 μmol/L). Like NaB, NaAC inhibited LPS-induced NF-κB activation. These results may hold promise on the role that SCFAs have on the prevention and treatment of various inflammatory conditions.

Embryonic development and gene expression of porcine SCNT embryos treated with sodium butyrate

Incomplete epigenetic modification is one of important reasons of inefficient reprogramming of the donor cell nuclei in ooplasm after somatic cell nuclear transfer (SCNT). It may also underlie the observed reduced viability of cloned embryos. Sodium butyrate (NaBu) is a natural histone deacetylase inhibitor that is produced in the intestine. In the current study, we evaluated the effects of NaBu on preimplantation development, histone acetylation, and gene expression in porcine SCNT embryos. Our results showed that the blastocyst rate (24.88 ± 2.09) of cloned embryos treated with 1.0 mM NaBu for 12 hr after activation was significantly higher (P < 0.05) than that of untreated cloned embryos (13.15 ± 3.07). In addition, treated embryos displayed a global acetylated histone H3 at lysine 14 profile similar to that of in vitro fertilized (IVF) embryos during preimplantation development. Lower levels of Oct4 and Bcl-2, but higher levels of Hdac1, in SCNT embryos at the two-cell and blastocyst stages were observed, compared with those in the IVF counterparts. The four-cell embryos showed no differences in the levels of these genes among IVF embryos or SCNT embryos treated with or without NaBu; however, the levels of Dnmt3b were significantly different. NaBu-treated SCNT embryos showed similar levels of Oct4, Bcl-2, and Dnmt3b as in IVF blastocysts. These results indicated that NaBu treatment in SCNT embryos alters their histone acetylation pattern to provide beneficial effects on in vitro developmental competence and gene expression.

Sodium butyrate potentiates carbon tetrachloride-induced acute liver injury in mice

Histone deacetylase 2 (HDAC2), a prominent member of the class I HDAC family, plays crucial roles in inflammation and other pathological processes. Recent studies have found that the activity and expression of HDAC2 were altered under oxidative stress conditions. The aim of the current study was to elucidate the expression and the possible pathophysiological significance of HDAC2 in CCl(4)-induced oxidative hepatitis. Our resultant data indicated that the expression of HDAC2 in liver increased after CCl(4) exposure, which was attenuated by antioxidants N-acetyl-L-cysteine or α-lipoic acid. Administration of sodium butyrate (NaB), a representative HDAC inhibitor resulted in further elevation of serum aminotransferase levels, enhanced oxidative stress, reduced antioxidant enzyme activities, increased production of proinflammatory cytokines and aggravated hepatocellular necrosis as well as leukocyte infiltration in liver. The results suggested that oxidative stress in CCl(4)-exposed mice induce the expression of HDAC2, while inhibition of HDAC result in exacerbated liver injury. Therefore, HDAC might be involved in the pathogenesis of CCl(4)-induced liver injury and provide protective benefit.

Transient exposure to sodium butyrate after germinal vesicle breakdown improves meiosis but not developmental competence in pig oocytes

Oocyte maturation is a complex process during which epigenetic modifications are dramatically changed, especially histone acetylation and phosphorylation. We have investigated the effects of NaBu (sodium butyrate), a natural HDAC (histone deacetylase) inhibitor, on porcine oocyte maturation at different stages and subsequent embryonic development to improve IVF (in vitro fertilization) and embryo production. COCs (cumulus oocyte complexes) were cultured, IVM (in vitro maturation) supplemented with 1 mM NaBu before or after GVBD [GV (germinal vesicle) breakdown] during maturation. NaBu delayed oocyte meiosis in the GV and GVBD stages in an exposure-dependent manner. However, the short treatment with 1 mM NaBu after GVBD significantly improved the meiotic competence. No positive effects of NaBu on GSH levels and subsequent embryonic development following IVF were seen. Transient exposure to NaBu after GVBD improves meiotic competence, but not subsequently, probably by having an effect on histone acetylation during oocyte maturation.

Butyrate-induced GPR41 activation inhibits histone acetylation and cell growth

Butyrate has been recently identified as a natural ligand of the G-protein-coupled receptor 41 (GPR41). In addition, it is an inhibitor of histone deacetylase (HDAC). Butyrate treatment results in the hyperacetylation of histones, with resultant multiple biological effects including inhibition of proliferation, induction of cell cycle arrest, and apoptosis, in a variety of cultured mammalian cells. However, it is not clear whether GPR41 is actively involved in the above-mentioned processes. In this study, we generated a stable cell line expressing the hGPR41 receptor in order to investigate the involvement of GPR41 on butyrate-induced biochemical and physiologic processes. We found that GPR41 activation may be a compensatory mechanism to counter the increase in histone H3 acetylation levels induced by butyrate treatment. Moreover, GPR41 had an inhibitory effect on the anti-proliferative, pro-apoptotic effects of butyrate. GPR41 expression induced cell cycle arrest at the G1-stage, while its activation by butyrate can cause more cells to pass the G1 checkpoint. These results indicated that GPR41 was associated with histone acetylation and might be involved in the acetylation-related regulation of cell processes including proliferation, apoptosis, and the cell cycle.

Methylation characteristics and developmental potential of Guangxi Bama minipig (Sus scrofa domestica) cloned embryos from donor cells treated with trichostatin A and 5-aza-2'-deoxycytidine

Summary Reprogramming of DNA methylation in somatic cell nuclear transfer (SCNT) embryos is incomplete, and aberrant DNA methylation patterns are related to the inefficiency of SCNT. To facilitate nuclear reprogramming, this study investigated the effect of treating Guangxi Bama minipig donor cells with trichostatin A (TSA), 5-aza-2'-deoxycytine (5-aza-dC), or combination of TSA and 5-aza-dC prior to nuclear transfer. Analyses showed that there were no major changes in cell-cycle status among all groups. We monitored the transcription of DNMT1, DNMT3a, HDAC1 and IGF2 genes in donor cells. Transcription levels of HDAC1 were decreased significantly after treatment with a combination of TSA and 5-aza-dC, along with a significantly increased level of IGF2 (P < 0.05). Although treatment of donor cells with either TSA or 5-aza-dC alone resulted in non-significant effects in blastocyst formation rate and DNA methylation levels, a combination of TSA and 5-aza-dC significantly improved the development rates of minipig SCNT embryos to blastocyst (25.6% vs. 16.0%, P < 0.05). This change was accompanied by decreased levels of DNA methylation in somatic cells and blastocyst (P < 0.05). Thus in combination with TSA, lower concentrations of 5-aza-dC may produce a potent demethylating activity, and lead to the significantly enhanced blastocyst development percentage of Bama minipig SCNT embryos.

Effect of valproic acid on cell proliferation and cell cycle progression in human hepatoma cell line SMMC-7721

AIM: To investigate the effect of valproic acid (VPA) on cell proliferation, cell cycle progression and expression of p21^WAF1/CIP1 mRNA in human hepatoma cell line SMMC-7721 in vitro.

METHODS: SMMC-7721 cells were treated with different concentrations (0.2, 1.0 and 5.0 mmol/L) of VPA for different durations (24, 48 and 72 h). Cell growth was measured by MTT assay. Cell cycle analysis was performed by flow cytometry. The expression of p21^WAF1/CIP1 mRNA in SMMC-7721 cells treated with VPA for 72 h was detected by RT-PCR.

RESULTS: Compared to the control group and PBS group, treatment with different concentrations of VPA for different durations significantly reduced cell growth to a varying extent (all P < 0.05). VPA administration suppressed cell proliferation in a time- and dose-dependent manner. After treatment with VPA, the percentage of cells in G₁ phase increased significantly and that of cells in S phase decreased, suggesting an arrest in G₀/G₁ phrase. Significant up-regulation of p21^WAF1/CIP1 mRNA was observed in SMMC-7721 cells 72 h after treatment with VPA.

CONCLUSION: VPA could significantly suppress cell proliferation in a time- and dose-dependent manner, and result in a cell cycle arrest in G₀/G₁ phase by inducing elevated expression of p21^WAF1/CIP1 mRNA in SMMC-7721 cells.

Somatic cell-induced hyperacetylation, but not hypomethylation, positively and reversibly affects the efficiency of in vitro cloned blastocyst production in cattle

5-Aza-2'-deoxycytidine (AzC), trichostatin A (TSA), and its natural mimetic, sodium butyrate (NaB), are antineoplastic drugs that can modify the epigenetic status of donor cells prior to somatic cell nuclear transfer (SCNT). In this study, we used fibroblast cells treated with these drugs to investigate the direct and indirect effects of induced changes in DNA methylation and acetylation of the lysine 9 residue of histone H3 (H3K9). Additionally, we assayed cellular characteristics (cell growth, cell proliferation, cell cycle progression, and apoptosis) and SCNT efficiency in response to these drugs as well as monitoring these effects 24 h after removing the drugs. We observed the following: (1) AzC, TSA, and NaB all showed dose-dependent effects on different cellular characteristics; (2) TSA and NaB induced H3K9 hyperacetylation accompanied by DNA hypermethylation, whereas AzC induced DNA hypomethylation with no effect on H3K9 hyperacetylation; (3) TSA and NaB improved cloning efficiency, whereas AzC reduced it; and (4) unlike AzC, the effects of TSA and NaB on cellular characteristics and SCNT efficiency were reversed following drug removal. Our results indicate that somatic cells treated with TSA and NaB show better survival and recovery rates following the removal of these drugs. Moreover, H3K9 hyperacetylation (induced with TSA and NaB), but not DNA hypomethylation (induced with AzC), favors cloning efficiency.

Inhibition of histone deacetylase causes emphysema

In patients with chronic obstructive pulmonary disease (COPD), histone deacetylase (HDAC) expression and activity are reduced in the lung tissue. However, whether HDAC activity controls the maintenance of the lung alveolar septal structures has not been investigated. To explore the consequences of HDAC inhibition and address the question of whether HDAC inhibition causes lung cell apoptosis and emphysema, male Sprague-Dawley rats and human pulmonary microvascular endothelial cells (HPMVEC) were treated with trichostatin A (TSA), a specific inhibitor of HDACs. Chronic TSA treatment increased the alveolar air space area, mean linear intercept, and the number of caspase-3-positive cells in rat lungs. TSA suppressed hypoxia-inducible factor-1α (HIF-1α), VEGF, and lysyl oxidase (LOX) and increased microtubule-associated protein-1 light chain 3 (LC3), p53, and miR34a microRNA expression in both rat lungs and cultured HPMVEC. Gene silencing of HDAC2 using small interfering RNA (siRNA) in cultured HPMVEC resulted in the suppression of HIF-1α, VEGF, and LOX and an increase of p53 expression. These data indicate that HDAC inhibition causes emphysema and that HDAC-dependent mechanisms contribute to the maintenance of the adult lung structure. Our results also suggest that the increase in apoptosis, as a consequence of HDAC inhibition, is associated with decreased VEGF and HIF-1α expression.

Upregulated histone deacetylase 1 expression in pancreatic ductal adenocarcinoma and specific siRNA inhibits the growth of cancer cells

OBJECTIVES

So far, there are no investigations about the role of histone deacetylase 1 (HDAC1) in tumorigenesis of pancreatic ductal adenocarcinoma. This study was designed to elucidate the roles and mechanisms of HDAC1 in tumorigenesis of pancreatic ductal adenocarcinoma.

METHODS

Real-time reverse transcription-polymerase chain reaction and immunohistochemistry techniques were adopted to detect the expression of HDAC1 in human pancreatic ductal adenocarcinoma tissues and paired paracancerous tissues. The roles of HDAC1 in human pancreatic cell line PaTu8988 were investigated using siRNA.

RESULTS

Histone deacetylase 1 mRNA in pancreatic cancer tissues were significantly higher than in paracancerous tissues (P < 0.05). Immunohistochemistry showed that the indices of HDAC1 in pancreatic cancer tissues and paracancerous tissues were 56.4% (SD, 23.1%) and 6.7% (SD, 5.0%), respectively (P < 0.001). Knockdown of HDAC1 can generate a remarkable defect in proliferation and also can significantly induce apoptosis and S-phase arrest in PaTu8988 cells (P < 0.05). The Bcl-2 mRNA expression was significantly downregulated, whereas the p21 and Bax mRNA expression were significantly upregulated.

CONCLUSIONS

The HDAC1 overexpression might play an important role in tumorigenesis of pancreatic cancer. Our data support the development of selective inhibitors targeting HDAC1 for the treatment of pancreatic ductal adenocarcinoma. Histone deacetylase 1 could be a new gene therapy target in pancreatic ductal adenocarcinoma.

Increasing histone acetylation of cloned embryos, but not donor cells, by sodium butyrate improves their in vitro development in pigs

Previous studies have demonstrated that increased histone acetylation in donor cells or cloned embryos, by applying a histone deacetylase inhibitor (HDACi) such as trichostatin A (TSA), significantly enhances their developmental competence. However, its effect may vary with the type of HDACi and the target species, with some research showing nonsignificant or detrimental effects of TSA on in vitro and in vivo development of embryos. In this study, we show that sodium salt of butyric acid, a short-chain fatty acid produced naturally in the body by bacterial degradation of dietary fibers in the colon and rectum, increases histone acetylation in pig fibroblast and embryos at a concentration of 1.0 and 5.0 mM, respectively. However, treatment of donor cells with NaBu did not affect the rate of blastocyst formation or embryo quality in terms of histone acetylation and total nuclei per blastocyst (p > 0.05). On the contrary, treatment of cloned pig embryos with NaBu for 4 h significantly enhanced (p < 0.01) the rate of blastocyst formation (18.3 +/- 2.1 vs. 11.2 +/- 3.0%), although the total nuclei number per blastocyst did not differ. More importantly, blastocysts generated from NaBu-treated cloned embryos had increased levels of histone acetylation that was comparable to those of in vitro fertilized (IVF) embryos (36.7 +/- 3.6 vs. 45.9 +/- 2.5). In conclusion, our data suggest that histone hyperacetylation by NaBu treatment of cloned embryos, but not donor cell, enhances their in vitro development up to blastocyst stage.

Effect of resveratrol on the development of porcine embryos produced in vitro

The effects of resveratrol (a phytoalexin with a wide variety of pharmacological activities) on pig embryos produced by parthenogenesis and/or in vitro fertilization have been investigated. First, parthenogenetic embryos were generated and cultured in PZM-3 medium supplemented with various amounts of resveratrol (0, 0.05, 0.1, 0.5, 1.0 and 25 microM final concentrations). In the presence of 0.5 microM resveratrol a significantly higher percentage of parthenogenetic embryos reached the blastocyst stage by day 7 compared to non-treated control (43.5+/-6.3% vs. 33.0+/-5.4%; P<0.05). The total cell number of blastocysts also increased as a result of incubation with 0.5 microM resveratrol; the difference was statistically significant between treated and non-treated embryos on day 5 of culture (35.8+/-0.9 vs. 32.1+/-1.1; P<0.05). Resveratrol incubation affected the expression levels of apoptosis-related genes in parthenogenetic blastocysts: the level of Bax transcripts was similar but lower expression of Bcl-2 and Caspase-3 was observed in embryos treated with 0.5 microM resveratrol when compared to control blastocysts (P<0.05). The results of the TUNEL assay were similar in blastocysts developing with or without resveratrol supplementation. In addition, when embryos produced by in vitro fertilization were incubated with 0.5 microM resveratrol, the treatment led to higher frequencies of blastocyst formation (8.6% vs. 13.3%) and elevated total cell numbers (37.1+/-2.4 vs. 43.2+/-1.7) by the end of the 7-day culture period (P<0.05). The results indicate that 0.5 microM resveratrol during culture has a positive effect on early embryonic development of porcine embryos.

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, diminishes lymphoproliferation in the Fas -deficient MRL/lpr(-/-) murine model of autoimmune lymphoproliferative syndrome (ALPS)

OBJECTIVE

Autoimmune lymphoproliferative syndrome (ALPS) is a disorder of apoptosis, often presenting in childhood. Similarly, MRL/lpr(-/-) mice homozygous for Fas mutations develop an ALPS-like disease with autoimmunity, lymphadenopathy, splenomegaly, and expansion of double-negative T cells. Currently, there are no proven therapies with adequate safety margins for sustained abolition of the lymphoproliferation associated with ALPS. We sought to test the ability of valproic acid (VPA), a histone deacetylase inhibitor, to induce apoptosis and inhibit lymphoproliferation.

MATERIALS AND METHODS

Human peripheral blood mononuclear cells from patients with ALPS and normal controls were tested in vitro to determine the efficacy of VPA at inducing cell death. VPA was used in vivo to control lymphoproliferation in MRL/lpr(-/-) mice, a model for ALPS.

RESULTS

VPA induced cell death in vitro, and was partially inhibited by the pan caspase inhibitor, Z-VAD-FMK. MRL/lpr(-/-) mice treated with VPA for 8 weeks showed significant reductions in spleen and lymph node weights and cellularity compared to controls. A concomitant decrease in double-negative T cells was observed in the spleen, lymph nodes, and peripheral blood. Serum levels of VPA peaked 1 hour after injection, and a 2.5-fold increase in histone acetylation was observed in the spleen at 4 hours after injection.

CONCLUSION

Based on our data, VPA is effective at reducing lymphoproliferation in mice, and is currently being studied in a clinical trial as a lympholytic agent in patients with ALPS.

MicroRNA expression patterns and function in endodermal differentiation of human embryonic stem cells

BACKGROUND/AIMS

microRNAs (miRNAs) are small noncoding RNAs that regulate cognate mRNAs post-transcriptionally. Human embryonic stem cells (hESC), which exhibit the characteristics of pluripotency and self-renewal, may serve as a model to study the role of miRNAs in early human development. We aimed to determine whether endodermally-differentiated hESC demonstrate a unique miRNA expression pattern, and whether overexpression of endoderm-specific miRNA may affect hESC differentiation.

METHODS

miRNA expression was profiled in undifferentiated and NaButyrate-induced differentiated hESC of two lines, using microarray and quantitative RT-PCR. Then, the effect of lentiviral-based overexpression of liver-specific miR-122 on hESC differentiation was analyzed, using genomewide gene microarrays.

RESULTS

The miRNA profiling revealed expression of three novel miRNAs in undifferentiated and differentiated hESC. Upon NaButyrate induction, two of the most upregulated miRNAs common to both cell lines were miR-24 and miR-10a, whose target genes have been shown to inhibit endodermal differentiation. Furthermore, induction of several liver-enriched miRNAs, including miR-122 and miR-192, was observed in parallel to induction of endodermal gene expression. Stable overexpression of miR-122 in hESC was unable to direct spontaneous differentiation towards a clear endodermal fate, but rather, delayed general differentiation of these cells.

CONCLUSIONS

Our results demonstrate that expression of specific miRNAs correlates with that of specific genes upon differentiation, and highlight the potential role of miRNAs in endodermal differentiation of hESC.