Histone deacetylase inhibitors exert time-dependent effects on nuclear factor-kappaB but consistently suppress the expression of proinflammatory genes in human myometrial cells

An insight into the concept of neuroinflammation and neurodegeneration in Alzheimer's disease: targeting molecular approach Nrf2, NF-κB, and CREB

Alzheimer's disease (AD) is a most prevalent neurologic disorder characterized by cognitive dysfunction, amyloid-β (Aβ) protein accumulation, and excessive neuroinflammation. It affects various life tasks and reduces thinking, memory, capability, reasoning and orientation ability, decision, and language. The major parts responsible for these abnormalities are the cerebral cortex, amygdala, and hippocampus. Excessive inflammatory markers release, and microglial activation affect post-synaptic neurotransmission. Various mechanisms of AD pathogenesis have been explored, but still, there is a need to debate the role of NF-κB, Nrf2, inflammatory markers, CREB signaling, etc. In this review, we have briefly discussed the signaling mechanisms and function of the NF-ĸB signaling pathway, inflammatory mediators, microglia activation, and alteration of autophagy. NF-κB inhibition is a current strategy to counter neuroinflammation and neurodegeneration in the brain of individuals with AD. In clinical trials, numbers of NF-κB modulators are being examined. Recent reports revealed that molecular and cellular pathways initiate complex pathological competencies that cause AD. Moreover, this review will provide extensive knowledge of the cAMP response element binding protein (CREB) and how these nuclear proteins affect neuronal plasticity.

Histone Deacetylase Inhibitors: Providing New Insights and Therapeutic Avenues for Unlocking Human Birth

The pregnant uterus remains relaxed throughout fetal gestation before transforming to a contractile phenotype at term to facilitate birth. Despite ongoing progress, the precise mechanisms that regulate this phenotypic transformation are not yet understood. This knowledge gap limits our understanding of how dysregulation of uterine smooth muscle biology contributes to life-threatening obstetric complications, including preterm birth, and hampers our ability to develop effective therapeutic intervention strategies. Protein acetylation plays a vital role in regulating protein structure, function, and subcellular localization, as well as gene transcription availability through regulating chromatin condensation. Histone deacetylase inhibitors (HDACis) are a class of compounds that block the removal of acetyl functional groups from proteins and, as such, have profound effects on important cellular events, including phenotypic transformation. A large body of data now demonstrates that HDACis have profound effects on pregnant human myometrium. Studies to date show that HDACis operate through both genomic and non-genomic mechanisms to affect myometrial function and phenotype. Interestingly, the effects of HDACis on pregnant myometrium are largely "pro-relaxation," including the direct inhibition of contractile machinery as well as repression of pro-labor genes. The "dual action" effects of HDACis make them a powerful tool for unlocking the regulatory processes that underpin myometrial phenotypic transformation and raises prospects of their therapeutic applications. Here, we review the new insights into human myometrial biology that have garnered through the application of HDACis and explore their potential therapeutic application toward the development of novel preterm birth prevention strategies.

Enhanced drug delivery to the reproductive tract using nanomedicine reveals therapeutic options for prevention of preterm birth

Inflammation contributes to nearly 4 million global premature births annually. Here, we used a mouse model of intrauterine inflammation to test clinically used formulations, as well as engineered nanoformulations, for the prevention of preterm birth (PTB). We observed that neither systemic 17a-hydroxyprogesterone caproate (Makena) nor vaginal progesterone gel (Crinone) was sufficient to prevent inflammation-induced PTB, consistent with recent clinical trial failures. However, we found that vaginal delivery of mucoinert nanosuspensions of histone deacetylase (HDAC) inhibitors, in some cases with the addition of progesterone, prevented PTB and resulted in delivery of live pups exhibiting neurotypical development. In human myometrial cells in vitro, the P4/HDAC inhibitor combination both inhibited cell contractility and promoted the anti-inflammatory action of P4 by increasing progesterone receptor B stability. Here, we demonstrate the use of vaginally delivered drugs to prevent intrauterine inflammation-induced PTB resulting in the birth of live offspring in a preclinical animal model.

Peptidomics analysis of myometrium tissues in term labor compared with term nonlabor

Preterm birth (PTB) is a major cause of neonatal mortality, with a poorly understood etiology. The regular contraction of the myometrium was considered as contributing to the etiology of the onset of labor, especially PTB. Thus, studying the mechanism of myometrium contraction is very important for understanding the initiation of labor and also for preventing PTB. Using liquid chromatography-mass spectrometry, we found 322 significantly differential peptides in myometrium tissues between term nonlabor and term labor groups (absolute fold change ≥ 2 and P < .05). We next analyzed length, molecular weights, isoelectric point, and cleavage site of all the different peptides. We, next, analyzed the functions of different peptides through their precursor proteins by Gene Ontology, enrichment and canonical pathway analysis. The results indicated that the extracellular matrix (ECM) played a major role in biological process, the cellular component, and molecular function categories, and revealed that ECM remodeling played a vital role in myometrial contraction. In addition, some known signaling, such as corticotropin-releasing hormone signaling and calcium signaling were proven to be involved in this process. Ingenuity Pathways Analysis upstream regulator analysis suggested that some of the known molecules, which reportedly were very important in labor onset, were included, for example, nuclear factor κB, tubulin, and phosphoinositide 3-kinase. We also identified 23 peptides derived from the precursor protein TITIN, of which 21 peptides sequences from TITIN were located in functional domains. These results suggested that peptides play an important role in labor onset and provide further insight into PTB therapy.

Multifactorial Regulation of Myometrial Contractility During Pregnancy and Parturition

The steroid hormones progesterone (P₄) and estradiol-17β (E₂), produced by the placenta in humans and the ovaries in rodents, serve crucial roles in the maintenance of pregnancy, and the initiation of parturition. Because of their critical importance for species survival, the mechanisms whereby P₄ and its nuclear receptor (PR) maintain myometrial quiescence during pregnancy, and for the decline in P₄/PR and increase in E₂/estrogen receptor (ER) function leading to parturition, are multifaceted, cooperative, and redundant. These actions of P₄/PR include: (1) PR interaction with proinflammatory transcription factors, nuclear factor κB (NF-κB), and activating protein 1 (AP-1) bound to promoters of proinflammatory and contractile/contraction-associated protein (CAP) genes and recruitment of corepressors to inhibit NF-κB and AP-1 activation of gene expression; (2) upregulation of inhibitors of proinflammatory transcription factor activation (IκBα, MKP-1); (3) induction of transcriptional repressors of CAP genes (e.g., ZEB1). In rodents and most other mammals, circulating maternal P₄ levels remain elevated throughout most of pregnancy and decline precipitously near term. By contrast, in humans, circulating P₄ levels and myometrial PR levels remain elevated throughout pregnancy and into labor. However, even in rodents, wherein P₄ levels decline near term, P₄ levels remain higher than the K_d for PR binding. Thus, parturition is initiated in all species by a series of molecular events that antagonize the P₄/PR maintenance of uterine quiescence. These events include: direct interaction of inflammatory transcription factors (e.g., NF-κB, AP-1) with PR; increased expression of P₄ metabolizing enzymes; increased expression of truncated/inhibitory PR isoforms; altered expression of PR coactivators and corepressors. This article will review various mechanisms whereby P₄ acting through PR isoforms maintains myometrial quiescence during pregnancy as well as those that underlie the decline in PR function leading to labor. The roles of P₄- and E₂-regulated miRNAs in the regulation and integration of these mechanisms will also be considered.

p38 Mitogen activated protein kinase (MAPK): a new therapeutic target for reducing the risk of adverse pregnancy outcomes

INTRODUCTION

Spontaneous preterm birth (PTB) and preterm premature rupture of the membranes (pPROM) remain as a major clinical and therapeutic problem for intervention and management. Current strategies, based on our knowledge of pathways of preterm labor, have only been effective, in part, due to major gaps in our existing knowledge of risks and risk specific pathways. Areas covered: Recent literature has identified physiologic aging of fetal tissues as a potential mechanistic feature of normal parturition. This process is affected by telomere dependent and p38 mitogen activated protein kinase (MAPK) induced senescence activation. Pregnancy associated risk factors can cause pathologic activation of this pathway that can cause oxidative stress induced p38 MAPK activation leading to senescence and premature aging of fetal tissues. Premature aging is associated with sterile inflammation capable of triggering preterm labor or preterm premature rupture of membranes. Preterm activation of p38MAPK can be considered as a key contributor to adverse pregnancies. Expert opinion: This review considers p38MAPK activation as a potential target for therapeutic interventions to prevent adverse pregnancy outcomes mediated by stress factors. In this review, we propose multiple strategies to prevent p38MAPK activation.

Altered expression of histone deacetylases, inflammatory cytokines and contractile-associated factors in uterine myometrium of Long Evans rats gestationally exposed to benzo[a]pyrene

Etiology of preterm birth (PTB) is multifactorial; therefore, decreasing the incidence of PTB is a major challenge in the field of obstetrics. Epidemiological studies have reported an association between toxicants and PTB. However, there are no studies on the role of benzo[a]pyrene (BaP), an environmental toxicant, in the incidence of PTB. We first assessed the effects of BaP (150 and 300 µg kg(-1) body weight) dosed via gavage from day 14 to 17 of pregnancy on gestation length in Long Evans rats. We further assessed the histopathology of the uterus, expression of inflammatory cytokines, contractile-associated factors, histone deacetylases (HDACs) and NFқB-p65 in myometrium collected on day 22 postpartum versus vehicle-treated controls. In our study, rats exposed to BaP delivered prematurely (P < 0.05) compared to control. Hematoxylin and eosin staining of uterus showed squamous metaplasia, glandular and stromal hyperplasia in BaP-exposed rats versus control. The concentrations of BaP metabolites measured by high-pressure liquid chromatography were higher in uterine myometrium of BaP-exposed rats while they were undetectable in controls. Quantitative real-time polymerase chain reaction showed significant increases in mRNA expression of interleukin-1β and -8, tumor necrosis factor-α, connexin 43, cyclo-oxygenase-2 and prostaglandin F2α receptor as compared to controls (P < 0.05). Western blot analysis revealed that BaP exposure caused decreases in class I HDACs 1 and 3 and increases in class II HDAC 5, cyclo-oxygenase-2 and nuclear translocation of NFκB-p65 relative to controls. Our results suggest that gestational exposure to BaP increases incidence of PTB through epigenetic changes that causes increases in the expression of contractile-associated factors through the NFκB pathway. Copyright © 2015 John Wiley & Sons, Ltd.

Class I to III histone deacetylases differentially regulate inflammation-induced matrix metalloproteinase 9 expression in primary amnion cells

Matrix metalloproteinase (MMP) 9 plays an important role in the degradation of the extracellular matrix in fetal membranes, and pathological activation of MMP-9 can lead to preterm birth. In nongestational tissues, modulation of histone deacetylases (HDACs) regulates MMP-9 expression. The aim of this study was to determine whether class I to III HDACs regulate MMP-9 expression and activity in primary amnion cells. Class I and II HDAC regulation of MMP-9 was assessed using the general class I and II HDAC inhibitors (HDACi) trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA), the class I HDACi MS-275, and the class II HDACi MC1568. Class III HDAC regulation of MMP-9 was assessed using the SIRT1 activators resveratrol and SRT1720 as well as SIRT1 small interfering RNA (siRNA). Primary amnion epithelial cells were incubated with 1 ng/mL interleukin (IL) 1β in the absence or presence of 0.3 μmol/L TSA, 5 μmol/L SAHA, 2.5 μmol/L MS-275, 2.5 μmol/L MC1568, 50 μmol/L resveratrol, or 10 μmol/L SRT1720 for 20 hours. We found that the class I and II HDACi TSA and SAHA and the class II HDACi MC1568 significantly decreased IL-β-induced MMP-9 gene and pro-MMP-9 expression in primary amnion cells. There was, however, no effect of the class I HDACi MS-275 on IL-β-induced MMP-9 expression. On the other hand, inhibition of class III HDAC SIRT1 using siRNA significantly augmented IL-1β-induced MMP-9, and SIRT1 activation using resveratrol and SRT1720 inhibited IL-1β-induced MMP-9 expression. In summary, class I to III HDACs differentially regulate inflammation-induced MMP-9 expression in primary amnion cells.

Histone deacetylases as targets for treatment of multiple diseases

HDACs (histone deacetylases) are a group of enzymes that deacetylate histones as well as non-histone proteins. They are known as modulators of gene transcription and are associated with proliferation and differentiation of a variety of cell types and the pathogenesis of some diseases. Recently, HDACs have come to be considered crucial targets in various diseases, including cancer, interstitial fibrosis, autoimmune and inflammatory diseases, and metabolic disorders. Pharmacological inhibitors of HDACs have been used or tested to treat those diseases. In the present review, we will examine the application of HDAC inhibitors in a variety of diseases with the focus on their effects of anti-cancer, fibrosis, anti-inflammatory, immunomodulatory activity and regulating metabolic disorders.

Sphingosine-1-phosphate links persistent STAT3 activation, chronic intestinal inflammation, and development of colitis-associated cancer

Inflammatory bowel disease is an important risk factor for colorectal cancer. We show that sphingosine-1-phosphate (S1P) produced by upregulation of sphingosine kinase 1 (SphK1) links chronic intestinal inflammation to colitis-associated cancer (CAC) and both are exacerbated by deletion of Sphk2. S1P is essential for production of the multifunctional NF-κB-regulated cytokine IL-6, persistent activation of the transcription factor STAT3, and consequent upregulation of the S1P receptor, S1PR1. The prodrug FTY720 decreased SphK1 and S1PR1 expression and eliminated the NF-κB/IL-6/STAT3 amplification cascade and development of CAC, even in Sphk2(-/-) mice, and may be useful in treating colon cancer in individuals with ulcerative colitis. Thus, the SphK1/S1P/S1PR1 axis is at the nexus between NF-κB and STAT3 and connects chronic inflammation and CAC.

Regulation of GTP-binding protein (Gαs) expression in human myometrial cells: a role for tumor necrosis factor in modulating Gαs promoter acetylation by transcriptional complexes

The onset of parturition is associated with a number of proinflammatory mediators that are themselves regulated by the nuclear factor κB (NF-κB) family of transcription factors. In this context, we previously reported that the RelA NF-κB subunit represses transcription and mRNA expression of the proquiescent Gαs gene in human myometrial cells following stimulation with the proinflammatory cytokine TNF. In the present study, we initially defined the functional consequence of this on myometrial contractility. Here we show that, contrary to our initial expectations, TNF did not induce myometrial contractility but did inhibit the relaxation produced by the histone deacetylase inhibitor trichostatin A, an effect that in turn was abolished by the NF-κB inhibitor N(4)-[2-(4-phenoxyphenyl)ethyl]-4,6-quinazolinediamine. This result suggested a role for TNF in regulating Gαs expression via activating NF-κB and modifying histone acetylation associated with the promoter region of the gene. In this context, we show that the -837 to -618 region of the endogenous Gαs promoter is occupied by cAMP-response element-binding protein (CREB), Egr-1, and Sp1 transcription factors and that CREB-binding protein (CBP) transcriptional complexes form within this region where they induce histone acetylation, resulting in increased Gαs expression. TNF, acting via NF-κB, did not change the levels of CREB, Sp1, or Egr-1 binding to the Gαs promoter, but it induced a significant reduction in the level of CBP. This was associated with increased levels of histone deacetylase-1 and surprisingly an increase in H4K8 acetylation. The latter is discussed herein.

A role for cytoskeletal protein acetylation in modulating myometrial activity

Posttranslational modifications (PTMs) of proteins by phosphorylation are a well-established mechanism by which their activities can be regulated to affect cellular physiology. However, it is becoming increasingly evident that PTMs of proteins by acetylation of lysine residues is also a key effecter in regulating their functional abilities. The best characterized case of this is the epigenetic effects of histone acetyltransferases and deacetylases on gene expression via modulation of nuclear histone acetylation and chromatin remodeling. However, recent published evidence now strongly implicates an important role for nonhistone acetylation in regulating cellular function. In this review, we have considered the potential for regulating myometrial activity not only by epigenetic mechanisms but also by nonepigenetic protein acetylation processes that could directly affect the contractile machinery within these smooth muscle cells.

Immune aspects and myometrial actions of progesterone and CRH in labor

Progesterone and corticotropin-releasing hormone (CRH) have a critical role in pregnancy and labor, as changes related to these hormones are crucial for the transition from myometrial quiescence to contractility. The mechanisms related to their effect differ between humans and other species, thus, despite extensive research, many questions remain to be answered regarding their mediation in human labor. Immune responses to progesterone and CRH are important for labor. Progesterone acts as an immunomodulator which controls many immune actions during pregnancy, and its withdrawal releases the inhibitory action on inflammatory pathways. In humans, a "functional" progesterone withdrawal occurs with onset of labor through changes in progesterone metabolism, progesterone receptors, and other molecules that either facilitate or antagonize progesterone function. Placental CRH acts on the fetal pituitary-adrenal axis to stimulate adrenal production of androgens and cortisol and also acts directly on myometrial cells via its receptors. CRH also affects inflammatory signals and vice versa. Interactions between progesterone and CRH additionally occur during labor. We describe the role of these two hormones in human myometrium and their interactions with the immune system during labor.

Induction of caspase mediated apoptosis and down-regulation of nuclear factor-κB and Akt signaling are involved in the synergistic antitumor effect of gemcitabine and the histone deacetylase inhibitor trichostatin A in human bladder cancer cells

PURPOSE

Previously we reported that the histone deacetylase inhibitor trichostatin A (Sigma®) synergistically potentiates the antitumor effects of cisplatin in human bladder cancer cells. In the current study we explored the synergistic interaction between trichostatin A and gemcitabine (Novartis Korea, Seoul, Korea), the other mainstay chemotherapeutic regimen for advanced bladder cancer.

MATERIALS AND METHODS

The bladder cancer cell lines HTB5, HTB9, T24, J82, UMUC14 and SW1710 (ATCC®) were exposed to gemcitabine and/or trichostatin A. Synergism between the 2 drugs was determined by the combination index based on the Cell Counting Kit-8 assay (Dojindo Molecular Technologies, Rockville, Maryland) and by a clonogenic assay. Flow cytometry was used to evaluate cell cycle distribution and apoptosis. The expression of cell cycle (p21(WAF1/CIP1), cyclin A, B1 and D1, p-CDC2C, CDC2C, p-CDC25C, CDC25C and pRb), apoptosis (caspase-3, 8 and 9, PARP, Bcl-2, Bad and Bax), NF-κB (NF-κB, p-IκBα, IκBα, p-IKKα, IKKα, cIAP1, cIAP2 and XIAP) and survival (p-Akt, Akt, p-mTOR, mTOR and PTEN) related proteins was analyzed by Western blot.

RESULTS

Isobolic analysis of the Cell Counting Kit-8 assay revealed strong synergism between gemcitabine and trichostatin A, which caused a 4.6 to 25.4-fold gemcitabine dose reduction and a 1.9 to 41.4-fold trichostatin A dose reduction while killing an estimated 90% of bladder cancer cells. The underlying mechanisms could be synergistic cell cycle arrest, induction of caspase mediated apoptosis, and down-regulation of the antiapoptotic NF-κB and Akt signaling pathways.

CONCLUSIONS

Results show that trichostatin A may synergistically enhance gemcitabine mediated cell cycle arrest and apoptosis, suggesting the potential of using histone deacetylase inhibitors as combination agents to enhance the antitumor effect of gemcitabine for advanced bladder cancer.

Regulation of CC ligand 5/RANTES by acid sphingomyelinase and acid ceramidase

Acid sphingomyelinase (aSMase) generates the bioactive lipid ceramide (Cer) from hydrolysis of sphingomyelin (SM). However, its precise roles in regulating specific sphingolipid-mediated biological processes remain ill defined. Interestingly, the aSMase gene gives rise to two distinct enzymes, lysosomal sphingomyelinase (L-SMase) and secretory sphingomyelinase (S-SMase) via alternative trafficking of a shared protein precursor. Previously, our laboratory identified Ser(508) as a crucial residue for the constitutive and regulated secretion of S-SMase in response to inflammatory cytokines, and demonstrated a role for S-SMase in formation of select cellular Cer species (Jenkins, R. W., Canals, D., Idkowiak-Baldys, J., Simbari, F., Roddy, P., Perry, D. M., Kitatani, K., Luberto, C., and Hannun, Y. A. (2010) J. Biol. Chem. 285, 35706-35718). In the present study using a chemokine/cytokine screen, we identified the chemokine CCL5 (formerly known as RANTES) as a candidate-specific downstream target for aSMase. Regulation of CCL5 by aSMase was subsequently validated using both loss-of-function and gain-of-function models indicating that aSMase is both necessary and sufficient for CCL5 production. Interestingly, cells deficient in acid ceramidase (aCDase) also exhibited defects in CCL5 induction, whereas cells deficient in sphingosine kinase-1 and -2 exhibited higher levels of CCL5, suggesting that sphingosine and not sphingosine 1-phosphate (S1P) is responsible for the positive signal to CCL5. Consistent with this, co-expression of aSMase and aCDase was sufficient to strongly induce CCL5. Taken together, these data identify a novel role for aSMase (particularly S-SMase) in chemokine elaboration by pro-inflammatory cytokines and highlight a novel and shared function for aSMase and aCDase.

Inhibition of LPS-induced C/EBP delta by trichostatin A has a positive effect on LPS-induced cyclooxygenase 2 expression in RAW264.7 cells

Cyclooxygenase 2 (COX-2) is an important inflammatory factor. Previous studies have indicated that COX-2 is induced with lipopolysaccharide (LPS) treatment. Here, we found that an inhibitor of histone deacetylase (HDAC), trichostatin A (TSA), cannot repress LPS-induced COX-2 but it increased the COX-2 level in RAW264.7 cells. We found no significant difference in NF-kappaB activation and ERK1/2 phosphorylation, but LPS-induced C/EBP delta expression was completely abolished after TSA treatment of LPS-treated cells. Interesting, reporter assay of C/EBP delta promoter revealed that Sp1-binding site is important. Although there was no alteration in c-Jun levels, but the phosphorylation of c-Jun at its C-terminus was increased dramatically. A DNA-associated protein assay (DAPA) and chromatin immunoprecipitation assay (ChIP) indicated that c-Jun was recruited via Sp1 to the promoter of C/EBP delta after LPS treatment; this recruitment of c-Jun was repressed by TSA. C/EBP delta inhibition by TSA resulted in increased binding of C/EBP alpha and C/EBP beta to the COX-2 promoter. Therefore, TSA has a positive effect on LPS-induced COX-2 since it decreases the C/EBP delta level by reducing c-Jun recruitment by Sp1 to the C/EBP delta promoter, resulting in increased the recruitment of C/EBP alpha and C/EBP beta to the COX-2 promoter.

Intermittent and sustained hypoxia induce a similar gene expression profile in human aortic endothelial cells

Obstructive sleep apnea may cause vascular inflammation and atherosclerosis, which has been attributed to intermittent hypoxia (IH). Recent data suggest that IH, but not sustained hypoxia (SH), activates proinflammatory genes in HeLa cells. Effects of IH and SH on the gene expression profile in human aortic endothelial cells (HAEC) have not been compared. We perfused media with alternating flow of 16% and 0% O2 (IH) or constant flow of 4% O2 (SH-4%), 8% O2 (SH-8%), or 16% O2 (control) for 8 h. Illumina gene microarrays were performed, with subsequent verification by real-time PCR. Proinflammatory cytokines in the media were measured by ELISA. Both IH and SH-4% upregulated proinflammatory genes, including heat shock protein 90-kDa B1, tumor necrosis factor superfamily member 4, and thrombospondin 1. Among all proinflammatory genes, only IL-8 mRNA showed significantly higher levels of expression (1.78-fold) during IH, compared with SH-4%, but both types of hypoxic exposure elicited striking three- to eightfold increases in IL-8 and IL-6 protein levels in the media. IH and SH-4% also upregulated antioxidant genes, including heme oxygenase-1 and nuclear factor (erythroid-derived 2)-like 2 (NRF2), whereas classical genes regulated by hypoxia-inducible factor 1 (HIF-1), such as endothelin and glucose transporter GLUT1, were not induced. SH-8% induced changes in gene expression and cytokine secretion that were similar to those of IH and SH-4%. In conclusion, short exposures to IH and SH upregulate proinflammatory and antioxidant genes in HAEC and increase secretion of proinflammatory cytokines IL-8 and IL-6 into media in similar fashions.