Histone deacetylase inhibitors block nuclear factor-κB-dependent transcription by interfering with RNA polymerase II recruitment

Mechanistic insight into the hepatoprotective effect of Moringa oleifera Lam leaf extract and telmisartan against carbon tetrachloride-induced liver fibrosis: plausible roles of TGF-β1/SMAD3/SMAD7 and HDAC2/NF-κB/PPARγ pathways

The increasing prevalence and limited therapeutic options for liver fibrosis necessitates more medical attention. Our study aims to investigate the potential molecular targets by which Moringa oleifera Lam leaf extract (Mor) and/or telmisartan (Telm) alleviate carbon tetrachloride (CCl4)-induced liver fibrosis in rats. Liver fibrosis was induced in male Sprague-Dawley rats by intraperitoneal injection of 50% CCl4 (1 ml/kg) every 72 hours, for 8 weeks. Intoxicated rats with CCl4 were simultaneously orally administrated Mor (400 mg/kg/day for 8 weeks) and/or Telm (10 mg/kg/day for 8 weeks). Treatment of CCl4-intoxicated rats with Mor/Telm significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities compared to CCl4 intoxicated group (P < 0.001). Additionally, Mor/Telm treatment significantly reduced the level of hepatic inflammatory, profibrotic, and apoptotic markers including; nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), transforming growth factor-βeta1 (TGF-β1), and caspase-3. Interestingly, co-treatment of CCl4-intoxicated rats with Mor/Telm downregulated m-RNA expression of histone deacetylase 2 (HDAC2) (71.8%), and reduced protein expression of mothers against decapentaplegic homolog 3 (p-SMAD3) (70.6%) compared to untreated animals. Mor/Telm regimen also elevated p-SMAD7 protein expression as well as m-RNA expression of peroxisome proliferator-activated receptor γ (PPARγ) (3.6 and 3.1 fold, respectively p < 0.05) compared to CCl4 intoxicated group. Histopathological picture of the liver tissue intoxicated with CCl4 revealed marked improvement by Mor/Telm co-treatment. Conclusively, this study substantiated the hepatoprotective effect of Mor/Telm regimen against CCl4-induced liver fibrosis through suppression of TGF-β1/SMAD3, and HDAC2/NF-κB signaling pathways and up-regulation of SMAD7 and PPARγ expression.

Histone deacetylase inhibitors as a potential new treatment for psoriatic disease and other inflammatory conditions

Collectively known as psoriatic disease, psoriasis and psoriatic arthritis (PsA) are immune-mediated inflammatory diseases in which patients present with cutaneous and musculoskeletal inflammation. Affecting roughly 2-3% of the world's total population, there remains unmet therapeutic needs in both psoriasis and PsA despite the availability of current immunomodulatory treatments. As a result, patients with psoriatic disease often experience reduced quality of life. Recently, a class of small molecules, commonly investigated as anti-cancer agents, called histone deacetylase (HDAC) inhibitors, have been proposed as a new promising anti-inflammatory treatment for immune- and inflammatory-related diseases. In inflammatory diseases, current evidence is derived from studies on diseases like rheumatoid arthritis (RA) and systematic lupus erythematosus (SLE), and while there are some reports studying psoriasis, data on PsA patients are not yet available. In this review, we provide a brief overview of psoriatic disease, psoriasis, and PsA, as well as HDACs, and discuss the rationale behind the potential use of HDAC inhibitors in the management of persistent inflammation to suggest its possible use in psoriatic disease.

Histone Deacetylases Cooperate with NF-κB to Support the Immediate Migratory Response after Zebrafish Pronephros Injury

Acute kidney injury (AKI) is commonly associated with severe human diseases, and often worsens the outcome in hospitalized patients. The mammalian kidney has the ability to recover spontaneously from AKI; however, little progress has been made in the development of supportive treatments. Increasing evidence suggest that histone deacetylases (HDAC) and NF-κB promote the pathogenesis of AKI, and inhibition of Hdac activity has a protective effect in murine models of AKI. However, the role of HDAC at the early stages of recovery is unknown. We used the zebrafish pronephros model to study the role of epigenetic modifiers in the immediate repair response after injury to the tubular epithelium. Using specific inhibitors, we found that the histone deacetylase Hdac2, Hdac6, and Hdac8 activities are required for the repair via collective cell migration. We found that hdac6, hdac8, and nfkbiaa expression levels were upregulated in the repairing epithelial cells shortly after injury. Depletion of hdac6, hdac8, or nfkbiaa with morpholino oligonucleotides impaired the repair process, whereas the combined depletion of all three genes synergistically suppressed the recovery process. Furthermore, time-lapse video microscopy revealed that the lamellipodia and filopodia formation in the flanking cells was strongly reduced in hdac6-depleted embryos. Our findings suggest that Hdac activity and NF-κB are synergistically required for the immediate repair response in the zebrafish pronephros model of AKI, and the timing of HDAC inhibition might be important in developing supportive protocols in the human disease.

Sepsis, immunosuppression and the role of epigenetic mechanisms

Introduction: Sepsis has pro- and anti-inflammatory processes caused by infectious agents. Sepsis survivors have impaired immune response due to immunosuppression. Gene expression during the inflammatory process is guided by transcriptional access to chromatin, with post-translational changes made in histones that determine whether the loci of the inflammatory gene are active, balanced, or suppressed. For this, a review literature was performed in PubMed included 'sepsis' and 'epigenetic' and 'immunosuppression' terms until May 2020.Areas covered: This review article explores the relationship between epigenetic mechanisms and the pathophysiology of sepsis. Epigenetic changes, vulnerable gene expression, and immunosuppression are related to inflammatory insults that can modify the dynamics of the central nervous system. Therefore, it is important to investigate the timing of these changes and their dynamics during the disease progression.Expert opinion: Epigenetic changes are associated with the main stages of sepsis, from the pathogen-host interaction to inflammation and immunosuppression. These changes are key regulators of gene expression during physiological and pathological conditions. Thus, epigenetic markers have significant prognostic and diagnostic potential in sepsis, and epigenetic changes can be explored in combination with therapeutic strategies in experimental models of the disease.

Proteomic Analysis of Inflammatory Biomarkers Associated With Breast Cancer Recurrence

INTRODUCTION

Breast cancer is the most frequent cancer detected for women, and while our ability to treat breast cancer has improved substantially over the years, recurrence remains a major obstacle. Standard screening for new and recurrent breast cancer involves clinical breast imaging. However, there is no clinically approved noninvasive body fluid test for the early detection of recurrent breast cancer. Materials and Method: In this study, we analyzed serum samples from both recurrent and nonrecurrent breast cancer patients by different proteomics methods to identify biomarkers in patients with recurrence of disease.

RESULTS

Comparative data analysis identified several histone deacetylase (HDAC) proteins, which were found at significantly higher levels in the serum of recurrent breast cancer patients: HDAC9 (C-term) (P = 0.0035), HDAC5 (C-term) (P = 0.013), small ubiquitin-like modifier 1 (N-term) (P = 0.017), embryonic stem cell-expressed Ras (inter) (P = 0.018), and HDAC7 (C-term) (P = 0.020). Chronic inflammation plays a critical role in the development of the breast cancer recurrence, and we identified several proinflammatory cytokines that were present at elevated levels only in recurrent breast cancer patient serum.

CONCLUSIONS

Our data indicated that the epigenetic regulation of inflammatory processes plays a critical role in breast cancer recurrence. The identified proteins could lay the groundwork for the development of a serum-based breast cancer recurrence assay.

Sodium butyrate alleviates lipopolysaccharide-induced endometritis in mice through inhibiting inflammatory response

Endometritis is commonly occurred in dairy cows after calving and results in a great deal of property damage. Although numerous studies have been performed to find the therapeutic agents for endometritis, the incidence of this disease remains high. Short-chain fatty acids (SCFAs), the major metabolic products of anaerobic bacteria fermentation in the gut, have been reported to exhibit anti-inflammatory properties. Therefore, the purpose of this study was to investigate the protective effects and mechanisms of sodium butyrate (SB) on lipopolysaccharide (LPS)-induced endometritis in mice. The mice were administered by intraperitoneal injection of SB at 1 h before LPS injection. 24 h later, the uterus tissues were collected. Hematoxylin and eosin (H & E) stained sections of uterus were used to determine the degree of the damage. Uterine myeloperoxidase (MPO) activity was used to analyze neutrophil granulocytes concentration. The levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured by ELISA. The activation of the NF-κB signaling pathway proteins were detected by Western blot analysis. The results showed that SB significantly attenuated the pathological injury of the uterus tissues. SB also suppressed LPS-induced MPO activity and the production of inflammatory cytokines TNF-α and IL-1β. Furthermore, Western blot analysis showed that SB inhibited the activation of NF-κB signaling pathway. In addition, SB could inhibit histone deacetylases. In summary, SB protects against LPS-induced endometritis through HDAC inhibition.

HDAC3 and HDAC8 are required for cilia assembly and elongation

Cilia are extended from mother centrioles in quiescent G0/G1 cells and retracted in dividing cells. Diverse post-translational modifications play roles in the assembly and disassembly of the cilium. Here, we examined class I histone deacetylases (HDACs) as positive regulators of cilia assembly in serum-deprived RPE1 and HK2 cells. We observed that the number of cells with cilia was significantly reduced in HDAC3- and HDAC8-depleted cells. The ciliary length also decreased in HDAC3- and HDAC8-depleted cells compared to that in control cells. A knockdown-rescue experiment showed that wild-type HDAC3 and HDAC8 rescued the cilia assembly and ciliary length in HDAC3- and HDAC8-depleted cells, respectively; however, deacetylase-dead HDAC3 and HDAC8 mutants did not. This suggests that deacetylase activity is critical for both HDAC3 and HDAC8 function in cilia assembly and ciliary length control. This is the first study to report that HDACs are required for the assembly and elongation of the primary cilia.

Summary: We identified that HDAC3 and HDAC8 are required for the assembly and elongation of the primary cilia.

TLR2/4-mediated NF-κB pathway combined with the histone modification regulates β-defensins and interleukins expression by sodium phenyl butyrate in porcine intestinal epithelial cells

Background

Host defense peptides (HDPs) possess direct antibacterial, antineoplastic, and immunomodulatory abilities, playing a vital role in innate immunity. Dietary-regulated HDP holds immense potential as a novel pathway for preventing infection.

Objective

In this study, we examined the regulation mechanism of HDPs (pEP2C, pBD-1, and pBD-3) and cytokines (IL-8 and IL-18) expression by sodium phenylbutyrate (PBA).

Design

The effects of PBA on HDP induction and the mechanism involved were studied in porcine intestinal epithelial cell lines (IPEC J2).

Results

In this study, the results showed that HDPs (pEP2C, pBD-1, and pBD-3) and cytokines (IL-8 and IL-18) expression was increased significantly upon stimulation with PBA in IPEC J2 cells. Furthermore, toll-like receptor 2 (TLR2) and TLR4 were required for the PBA-mediated upregulation of the HDPs. This process occurred and further activated the NF-κB pathway via the phosphorylation of p65 and an IκB α synthesis delay. Meanwhile, histone deacetylase (HDAC) inhibition and an increased phosphorylation of histone H3 on serine S10 also occurred in PBA-induced HDP expression independently with TLR2 and TLR4. Furthermore, p38-MAPK suppressed PBA-induced pEP2C, pBD-1 pBD-3, IL-8, and IL-18 expression, but ERK1/2 failed to abolish the regulation of pBD-3, IL-8, and IL-18. Moreover, epidermal growth factor receptor (EGFR) is involved in PBA-mediated HDP regulation.

Conclusions

We concluded that PBA induced HDP and cytokine increases but did not cause an excessive pro-inflammatory response, which proceeded through the TLR2 and TLR4-NF-κB pathway and histone modification in IPEC J2 cells.

Inhibition of histone deacetylase 1 or 2 reduces induced cytokine expression in microglia through a protein synthesis independent mechanism

Histone deacetylase (HDAC) inhibitors prevent neural cell death in in vivo models of cerebral ischaemia, brain injury and neurodegenerative disease. One mechanism by which HDAC inhibitors may do this is by suppressing the excessive inflammatory response of chronically activated microglia. However, the molecular mechanisms underlying this anti-inflammatory effect and the specific HDAC responsible are not fully understood. Recent data from in vivo rodent studies have shown that inhibition of class I HDACs suppresses neuroinflammation and is neuroprotective. In our study, we have identified that selective HDAC inhibition with inhibitors apicidin, MS-275 or MI-192, or specific knockdown of HDAC1 or 2 using siRNA, suppresses the expression of cytokines interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in BV-2 murine microglia activated with lipopolysaccharide (LPS). Furthermore, we found that in the absence of HDAC1, HDAC2 is up-regulated and these increased levels are compensatory, suggesting that these two HDACs have redundancy in regulating the inflammatory response of microglia. Investigating the possible underlying anti-inflammatory mechanisms suggests an increase in protein expression is not important. Taken together, this study supports the idea that inhibitors selective towards HDAC1 or HDAC2, may be therapeutically useful for targeting neuroinflammation in brain injuries and neurodegenerative disease.

Inhibition of HDAC enhances STAT acetylation, blocks NF-κB, and suppresses the renal inflammation and fibrosis in Npr1 haplotype male mice

Guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) plays a critical role in the regulation of blood pressure and fluid volume homeostasis. Mice lacking functional Npr1 (coding for GC-A/NPRA) exhibit hypertension and congestive heart failure. However, the underlying mechanisms remain largely less clear. The objective of the present study was to determine the physiological efficacy and impact of all-trans-retinoic acid (ATRA) and sodium butyrate (NaBu) in ameliorating the renal fibrosis, inflammation, and hypertension in Npr1 gene-disrupted haplotype (1-copy; +/-) mice (50% expression levels of NPRA). Both ATRA and NaBu, either alone or in combination, decreased the elevated levels of renal proinflammatory and profibrotic cytokines and lowered blood pressure in Npr1+/- mice compared with untreated controls. The treatment with ATRA-NaBu facilitated the dissociation of histone deacetylase (HDAC) 1 and 2 from signal transducer and activator of transcription 1 (STAT1) and enhanced its acetylation in the kidneys of Npr1+/- mice. The acetylated STAT1 formed a complex with nuclear factor-κB (NF-κB) p65, thereby inhibiting its DNA-binding activity and downstream proinflammatory and profibrotic signaling cascades. The present results demonstrate that the treatment of the haplotype Npr1+/- mice with ATRA-NaBu significantly lowered blood pressure and reduced the renal inflammation and fibrosis involving the interactive roles of HDAC, NF-κB (p65), and STAT1. The current findings will help in developing the molecular therapeutic targets and new treatment strategies for hypertension and renal dysfunction in humans.

Integrative functional genomic delineation of the cascades of transcriptional changes involved in hepatocellular carcinoma progression

Development of targeted therapeutics is still at its early stage for hepatocellular carcinoma (HCC) due to the incomplete understanding of the confounding regulations at signaling pathway level. In this investigation, gene co-expression-based networking and integrative functional genomic modeling of HCC mRNA profiles as signaling processes were employed to understand the complex signaling cascades involved in HCC development toward understanding the avenues for targeted therapeutics. Multiple sets of genes and molecular biological processes involved during HCC development were identified from this integrative analysis: (i) Loss of liver cellular features due to the reduced HNF4A & PPAR signaling in the early stages of HCC, (ii) activated inflammatory and stress signals in the cirrhosis stages and (iii) highly activated cellular proliferation with the activated E2F-MYC oncogenic signaling with the gain of embryonic liver stem cell-like features in the advanced stage tumors. Upon connecting these gene-sets with the established drug sensitivity-related gene signatures, targeted therapeutic strategies for the heterogeneous HCC conditions have been identified. PPAR agonist class of drugs for early stage HCC conditions, anti-inflammatory drugs for cirrhosis and topoisomerase inhibitors for the advanced HCC conditions were inferred. Integrative functional genomic analysis of HCC transcriptome profiles at the context of signaling pathways has defined the key molecular processes involved in HCC development. Further, the study highlights the stage-specific and pathway focused targeted therapeutics for HCC. These findings deserve extensive preclinical explorations toward the establishment of targeted therapeutics.

A structure-activity relationship of non-peptide macrocyclic histone deacetylase inhibitors and their anti-proliferative and anti-inflammatory activities

Inhibition of the enzymatic activity of histone deacetylase (HDAC) is a promising therapeutic strategy for cancer treatment and several distinct small molecule histone deacetylase inhibitors (HDACi) have been reported. We have previously identified a new class of non-peptide macrocyclic HDACi derived from 14- and 15-membered macrolide skeletons. In these HDACi, the macrocyclic ring is linked to the zinc chelating hydroxamate moiety through a para-substituted aryl-triazole cap group. To further delineate the depth of the SAR of this class of HDACi, we have synthesized series of analogous compounds and investigated the influence of various substitution patterns on their HDAC inhibitory, anti-proliferative and anti-inflammatory activities. We identified compounds 25b and 38f with robust anti-proliferative activities and compound 26f (IC50 47.2 nM) with superior anti-inflammatory (IC50 88 nM) activity relative to SAHA.

Epigenetic modifiers reduce inflammation and modulate macrophage phenotype during endotoxemia-induced acute lung injury

Acute lung injury (ALI) during sepsis is characterized by bilateral alveolar infiltrates, lung edema and respiratory failure. Here, we examined the efficacy the DNA methyl transferase (DNMT) inhibitor 5-Aza 2-deoxycytidine (Aza), the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA), as well as the combination therapy of Aza and TSA (Aza+TSA) provides in the protection of ALI. In LPS-induced mouse ALI, post-treatment with a single dose of Aza+TSA showed substantial attenuation of adverse lung histopathological changes and inflammation. Importantly, these protective effects were due to substantial macrophage phenotypic changes observed in LPS-stimulated macrophages treated with Aza+TSA as compared with untreated LPS-induced macrophages or LPS-stimulated macrophages treated with either drug alone. Further, we observed significantly lower levels of pro-inflammatory molecules and higher levels of anti-inflammatory molecules in LPS-induced macrophages treated with Aza+TSA than in LPS-induced macrophages treated with either drug alone. The protection was ascribed to dual effects by an inhibition of MAPK-HuR-TNF and activation of STAT3-Bcl2 pathways. Combinatorial treatment with Aza+TSA reduces inflammation and promotes an anti-inflammatory M2 macrophage phenotype in ALI, and has a therapeutic potential for patients with sepsis.

Histone deacetylase 5 regulates the inflammatory response of macrophages

Modifying the chromatin structure and interacting with non-histone proteins, histone deacetylases (HDAC) are involved in vital cellular processes at different levels. We here specifically investigated the direct effects of HDAC5 in macrophage activation in response to bacterial or cytokine stimuli. Using murine and human macrophage cell lines, we studied the expression profile and the immunological function of HDAC5 at transcription and protein level in over-expression as well as RNA interference experiments. Toll-like receptor-mediated stimulation of murine RAW264.7 cells significantly reduced HDAC5 mRNA within 7 hrs but presented baseline levels after 24 hrs, a mechanism that was also found for Interferon-γ treatment. If treated with lipopolysaccharide, RAW264.7 cells transfected for over-expression only of full-length but not of mutant HDAC5, significantly elevated secretion of tumour necrosis factor α and of the monocyte chemotactic protein-1. These effects were accompanied by increased nuclear factor-κB activity. Accordingly, knock down of HDAC5-mRNA expression using specific siRNA significantly reduced the production of these cytokines in RAW264.7 or human U937 cells. Taken together, our results suggest a strong regulatory function of HDAC5 in the pro-inflammatory response of macrophages.

c-FLIP is involved in tumor progression of peripheral T-cell lymphoma and targeted by histone deacetylase inhibitors

Background

Peripheral T-cell lymphomas (PTCLs) are often aggressive tumors and resistant to conventional chemotherapy. Dysregulation of extrinsic apoptosis plays an important role on tumor cell sensitivity to chemotherapeutic agents. Cellular FLICE inhibitory protein (c-FLIP) is a key regulator of extrinsic apoptotic pathway.

Methods

c-FLIP expression was assessed by real-time PCR and compared according to clinical parameters in patients with PTCLs. The relation of c-FLIP to tumor cell apoptosis mediated by histone deacetylases inhibitors (HDACIs) and the possible mechanism were examined in T-lymphoma cell lines and in a murine xenograft model.

Results

c-FLIP was overexpressed and associated with decreased tumor TRAIL/DR5 expression, elevated serum lactate dehydrogenase level and high-risk International Prognostic Index of the patients. In vitro, molecular silencing of c-FLIP by specific small-interfering RNA increased TRAIL/DR5 expression, enhanced T-lymphoma cell apoptosis and sensitized cells to chemotherapeutic agents. However, HDACIs valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA) could downregulate c-FLIP expression and triggered extrinsic apoptosis of T-lymphoma cells, through inhibiting NF-κB signaling and interrupting P50 interaction with c-FLIP promoter. As Class I HDACIs, both VPA and SAHA inhibited HDAC1, resulting in P50 inactivation and c-FLIP downregulation. In vivo, oral VPA treatment significantly retarded tumor growth and induced in situ apoptosis, consistent with inhibition of HDAC1/P50/c-FLIP axis and increase of TRAIL/DR5 expression.

Conclusions

c-FLIP overexpression in PTCLs protected tumor cells from extrinsic apoptosis and contributed to tumor progression. Although linking to chemoresistance, c-FLIP indicated tumor cell sensitivity to HDACIs, providing a potential biomarker of targeting apoptosis in treating PTCLs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-014-0088-y) contains supplementary material, which is available to authorized users.

Expression profiling of choline and ethanolamine kinases in MCF7, HCT116 and HepG2 cells, and the transcriptional regulation by epigenetic modification

The function of choline kinase (CK) and ethanolamine kinase (EK) is to catalyse the phosphorylation of choline and ethanolamine, respectively, in order to yield phosphocholine (PCho) and phosphoethanolamine (PEtn). A high expression level of PCho, due to elevated CK activity, has previously been associated with malignant transformation. In the present study, a quantitative polymerase chain reaction was performed to determine the mRNA expression profiles of ck and ek mRNA variants in MCF7 breast, HCT116 colon and HepG2 liver cancer cells. The ck and ek mRNA expression profiles showed that total ckα was expressed most abundantly in the HepG2 cells. The HCT116 cells exhibited the highest ckβ and ek1 mRNA expression levels, whereas the highest ek2α mRNA expression levels were detected in the MCF7 cells. The ckβ variant had higher mRNA expression levels, as compared with total ckα, in both the MCF7 and HCT116 cells. Relatively low ek1 mRNA expression levels were detected, as compared with ek2α in the MCF7 cells; however, this was not observed in the HCT116 and HepG2 cells. Notably, the mRNA expression levels of ckα2 were markedly low, as compared with ckα1, in all three cancer cell lines. The effects of epigenetic modification on ck and ek mRNA expression, by treatment of the cells with the histone deacetylase inhibitor trichostatin A (TSA), were also investigated. The results of the present study showed that the mRNA expression levels of ckα, ckβ and ek2α were affected by TSA. An increase >8-fold was observed in ek2α mRNA expression upon treatment with TSA, in a concentration- and time-dependent manner. In conclusion, the levels of ck and ek transcript variants in the three cancer cell lines were varied. The effects of TSA treatment on the mRNA expression levels of ck and ek imply that ck and ek mRNA expression may be regulated by epigenetic modification.

USP22 transcriptional activity is negatively regulated by the histone deacetylase inhibitor trichostatin A

The ubiquitin‑specific protease 22 (USP22) gene is overexpressed in the majority of types of cancer cells, and has been implicated in tumorigenesis. However, the mechanisms that regulate its expression remain unclear. The results of the present study demonstrated that the expression of USP22 is negatively regulated by trichostatin A (TSA), a classical histone deacetylase inhibitor. Furthermore, TSA was revealed to interfere with the binding of RNA polymerase II to the USP22 promoter, directly suppressing its transcription. In addition, the overexpression of USP22 was observed to attenuate TSA‑induced apoptosis in HeLa cells. To the best of our knowledge, these results provide the first insight into the regulation of the USP22 gene by antitumor drugs and into the mechanisms underlying the anticancer activity of TSA.

Combinatorial therapy with acetylation and methylation modifiers attenuates lung vascular hyperpermeability in endotoxemia-induced mouse inflammatory lung injury

Impairment of tissue fluid homeostasis and migration of inflammatory cells across the vascular endothelial barrier are crucial factors in the pathogenesis of acute lung injury (ALI). The goal for treatment of ALI is to target pathways that lead to profound dysregulation of the lung endothelial barrier. Although studies have shown that chemical epigenetic modifiers can limit lung inflammation in experimental ALI models, studies to date have not examined efficacy of a combination of DNA methyl transferase inhibitor 5-Aza 2-deoxycytidine and histone deacetylase inhibitor trichostatin A (herein referred to as Aza+TSA) after endotoxemia-induced mouse lung injury. We tested the hypothesis that treatment with Aza+TSA after lipopolysaccharide induction of ALI through epigenetic modification of lung endothelial cells prevents inflammatory lung injury. Combinatorial treatment with Aza+TSA mitigated the increased endothelial permeability response after lipopolysaccharide challenge. In addition, we observed reduced lung inflammation and lung injury. Aza+TSA also significantly reduced mortality in the ALI model. The protection was ascribed to inhibition of the eNOS-Cav1-MLC2 signaling pathway and enhanced acetylation of histone markers on the vascular endothelial-cadherin promoter. In summary, these data show for the first time the efficacy of combinatorial Aza+TSA therapy in preventing ALI in lipopolysaccharide-induced endotoxemia and raise the possibility of an essential role of DNA methyl transferase and histone deacetylase in the mechanism of ALI.

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.

Valproic acid: an anticonvulsant drug with potent antinociceptive and anti-inflammatory properties

Valproic acid (VA) is a major antiepileptic drug, used for several therapeutic indications. It has a wide activity spectrum, reflecting on mechanisms of action that are not fully understood. The objectives of this work were to study the effects of VA on acute models of nociception and inflammation in rodents. VA (0.5, 1, 10, 25, and 50 mg/kg, p.o.) effects were evaluated on the carrageenan-induced paw edema, carrageenan-induced peritonitis, and plantar tests in rats, as well as by the formalin test in mice. The HE staining and immunohistochemistry assay for TNF-α in carrageenan-induced edema, from paws of untreated and VA-treated rats, were also carried out. VA decreased paw edema after carrageenan, and maximum effects were seen with doses equal to or higher than 10 mg/kg. VA also preserved the tissue architecture as assessed by the HE staining. Immunohistochemical studies revealed that VA significantly reduced TNF-α immunostaining in carrageenan-inflamed rat paws. In addition, the anti-inflammatory action of VA was potentiated by pentoxifylline (a phosphodiesterase inhibitor, known to inhibit TNF-α production), but not by sodium butyrate or by suberoylanilide hydroxamic acid (SAHA), nonspecific and specific inhibitors, respectively, of histone deacetylase. However, the decrease in the number of positive TNF-α cells in the rat paw was drastically potentiated in the VA + SAHA associated group. VA also reduced leukocytes and myeloperoxidase (MPO) releases to the peritoneal exudate, in the carrageenan-induced peritonitis. Although in the formalin test, VA inhibited both phases, the inhibition was mainly on the second phase. Furthermore, VA significantly increased the reaction time to thermal stimuli, as assessed by the plantar test. VA is a multi-target drug, presenting potent antinociceptive and anti-inflammatory properties at a lower dose range. These effects are partly dependent upon its inhibitory action on TNF-α-related pathways. However, the participation of the HDAC inhibition with the VA anti-inflammatory action cannot be ruled out. Inflammatory processes are associated with free radical damage and oxidative stress, and their blockade by VA could also explain the present results.

Enhancement of inflammatory protein expression and nuclear factor Κb (NF-Κb) activity by trichostatin A (TSA) in OP9 preadipocytes

The production of inflammatory proteins such as interleukin-6 (IL-6) by preadipocytes and mature adipocytes is closely associated with the impairment of systemic glucose homeostasis. However, precisely how the production is regulated and the roles of histone deacetylases (HDACs) remain largely unknown. The aim of this study was to establish whether HDAC inhibitors affect the expression of inflammatory proteins in pre/mature adipocytes, and, if so, to determine the mechanism involved. Trichostatin A (TSA), an HDAC inhibitor, enhanced lipopolysaccharide (LPS)-induced production of IL-6 in OP9 preadipocytes but not the mature adipocytes. Moreover, TSA also enhanced palmitic acid-induced IL-6 production and the expression of inflammatory genes induced by LPS in preadipocytes. Although TSA did not affect TLR4 mRNA expression or the activation of MAPKs, a reporter gene assay revealed that the LPS-induced increase in nuclear factor κB (NF-κB) activity was enhanced by TSA. Moreover, TSA increased the level of NF-κB p65 acetylation at lysine 310 and duration of its translocation into the nucleus, which leads to enhancement of NF-κB activity and subsequently expression of inflammatory genes. These findings shed new light on the regulatory roles of HDACs in preadipocytes in the production of inflammatory proteins.

Fingolimod phosphate promotes the neuroprotective effects of microglia

Fingolimod phosphate (FTY720) is a sphingosine 1-phosphate (S1P) receptor agonist that is being used as a new oral drug for multiple sclerosis. FTY720 prevents lymphocytes from moving out of the lymphoid organs and inhibits autoreactive lymphocytes from infiltrating the central nervous system. Whether FTY720 directly affects microglia-the innate immune cells of the central nervous system-is unclear. Here we show that FTY720 binds S1P1 receptors to downregulate activated microglial production of such pro-inflammatory cytokines as tumor necrosis factor-α, interleukin-1β, and interleukin-6. FTY720 also upregulates microglial production of brain-derived neurotrophic factor and glial cell-derived neurotrophic factor. These results suggested that FTY720 directly promotes the neuroprotective effects of microglia. Therefore, FTY720 may be a potent therapeutic agent for not only multiple sclerosis but also other neurologic diseases associated with microglial activation.

Inhibition of the proliferation of acquired aromatase inhibitor-resistant breast cancer cells by histone deacetylase inhibitor LBH589 (panobinostat)

Aromatase inhibitors (AIs) are important drugs for treating postmenopausal patients with hormone receptor-positive breast cancer. However, acquired resistance to AI therapies is a significant problem. Our study has revealed that the histone deacetylase inhibitor LBH589 treatment abrogated growth of AI-resistant cells in vitro and in vivo, causing cell cycle G2/M arrest and induced apoptosis. LBH589 treatment also reduced the level of NF-κB1 which is overexpressed when AI resistance develops. Analyzing paired tumor specimens from 12 patients, we found that NF-κB1 expression was increased in recurrent AI-resistant tumors as compared to the paired primary tumors before AI treatment. This finding was consistent with up-regulated NF-κB1 expression seen in a collection of well-established AI-resistant cell lines. Furthermore, knockdown of NF-κB1 expression significantly suppressed the proliferation of AI-resistant cells. Treatment of AI-resistant cell lines with LBH589 suppressed NF-κB1 mRNA and protein expression. In addition, LBH589 treatment abrogated growth of AI-resistant tumors in mice, and was associated with significantly decreased levels of NF-κB1 in tumors. In all, our findings strongly support further investigation of LBH589 as a novel therapeutic strategy for patients with AI-resistant breast cancer, in part by suppressing the NF-κB1 pathway.

Substance P induces CCN1 expression via histone deacetylase activity in human colonic epithelial cells

We have shown that substance P (SP) and its neurokinin-1 receptor (NK-1R) regulate intestinal angiogenesis by increasing expression of protein CYR61 (the cysteine-rich angiogenic inducer 61, or CCN1) in colonic epithelial cells. However, the mechanism involved in SP-induced CCN1 expression has not been studied, and the outcome of increased CCN1 expression in the development of colitis is not fully understood. Because histone deacetylase (HDAC) modulates transcription of several genes involved in inflammation, we investigated participation of HDAC in SP-induced CCN1 expression in human colonic epithelial NCM460 cells overexpressing NK-1R (NCM460-NK-1R) and in primary colonocytes. SP increased HDAC activity with deacetylation and dephosphorylation of nucleosome protein histone H3 in NCM460-NK-1R and/or primary colonocytes. Histone deacetylation and dephosphorylation was observed in colonic mucosa from irritable bowel disease patients. Similarly, colonic mucosal tissues from mice exposed to dextran sulfate sodium showed histone H3 deacetylation and dephosphorylation and increased HDAC activity that was reversed by the NK-1R antagonist CJ-12255. SP-induced increased CCN1 expression in NCM460-NK-1R cells was abolished by pharmacological HDAC inhibition. HDAC overexpression activated basal and SP-induced CCN1 promoter activity. Intracolonic CCN1 overexpression significantly ameliorated dextran sulfate sodium-induced colitis, with reduction of proinflammatory cytokine expression in mice. Thus, SP-mediated CCN1 expression in the inflamed human and mouse colon involves increased HDAC activity. Our results strongly suggest that increased CCN1 expression may be involved in mucosal healing during colitis.