Inhibitors of histone deacetylases as anti-inflammatory drugs

Inhibition of histone-deacetylase activity rescues inflammatory cystic fibrosis lung disease by modulating innate and adaptive immune responses

Background

Chronic lung disease resulting from dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) and NFκB-mediated neutrophilic-inflammation forms the basis of CF-related mortality. Here we aimed to evaluate if HDAC inhibition controls Pseudomonas-aeruginosa-lipopolysaccharide (Pa-LPS) induced airway inflammation and CF-lung disease.

Methods

For in vitro experiments, HEK293-cells were transfected with IL-8 or NFκB-firefly luciferase, and SV40-renilla- luciferase reporter constructs or ΔF508-CFTR-pCEP, followed by treatment with suberoylanilide hydroxamic acid (SAHA), Trichostatin-A (TSA) and/or TNFα. For murine studies, Cftr^+/+ or Cftr^−/− mice (n = 3) were injected/instilled with Pa-LPS and/or treated with SAHA or vehicle control. The progression of lung disease was monitored by quantifying changes in inflammatory markers (NFκB), cytokines (IL-6/IL-10), neutrophil activity (MPO, myeloperoxidase and/or NIMP-R14) and T-reg numbers.

Results

SAHA treatment significantly (p < 0.05) suppresses TNFα-induced NFκB and IL-8 reporter activities in HEK293-cells. Moreover, SAHA, Tubacin (selective HDAC6-inhibitor) or HDAC6-shRNAs controls CSE-induced ER-stress activities (p < 0.05). In addition, SAHA restores trafficking of misfolded-ΔF508-CFTR, by inducing protein levels of both B and C forms of CFTR. Murine studies using Cftr^+/+ or Cftr^−/− mice verified that SAHA controls Pa-LPS induced IL-6 levels, and neutrophil (MPO levels and/or NIMP-R14), NFκB-(inflammation) and Nrf2 (oxidative-stress marker) activities, while promoting FoxP3⁺ T-reg activity.

Conclusion

In summary, SAHA-mediated HDAC inhibition modulates innate and adaptive immune responses involved in pathogenesis and progression of inflammatory CF-lung disease.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0705-8) contains supplementary material, which is available to authorized users.

Implication of the intestinal microbiome as a potential surrogate marker of immune responsiveness to experimental therapies in autoimmune diabetes

Type 1 diabetes (T1D) is an autoimmune proinflammatory disease with no effective intervention. A major obstacle in developing new immunotherapies for T1D is the lack of means for monitoring immune responsiveness to experimental therapies. The LEW1.WR1 rat develops autoimmunity following infection with the parvovirus Kilham rat virus (KRV) via mechanisms linked with activation of proinflammatory pathways and alterations in the gut bacterial composition. We used this animal to test the hypothesis that intervention with agents that block innate immunity and diabetes is associated with a shift in the gut microbiota. We observed that infection with KRV results in the induction of proinflammatory gene activation in both the spleen and pancreatic lymph nodes. Furthermore, administering animals the histone deacetylase inhibitor ITF-2357 and IL-1 receptor antagonist (Anakinra) induced differential STAT-1 and the p40 unit of IL-12/IL-23 gene expression. Sequencing of bacterial 16S rRNA genes demonstrated that both ITF-2357 and Anakinra alter microbial diversity. ITF-2357 and Anakinra modulated the abundance of 23 and 8 bacterial taxa in KRV-infected animals, respectively, of which 5 overlapped between the two agents. Lastly, principal component analysis implied that ITF-2357 and Anakinra induce distinct gut microbiomes compared with those from untreated animals or rats provided KRV only. Together, the data suggest that ITF-2357 and Anakinra differentially influence the innate immune system and the intestinal microbiota and highlight the potential use of the gut microbiome as a surrogate means of assessing anti-inflammatory immune effects in type 1 diabetes.

Development of histone deacetylase inhibitors for cancer treatment

Histone deacetylase (HDAC) inhibitors are an exciting new addition to the arsenal of cancer therapeutics. The inhibition of HDAC enzymes by HDAC inhibitors shifts the balance between the deacetylation activity of HDAC enzymes and the acetylation activity of histone acetyltransferases, resulting in hyperacetylation of core histones. Exposure of cancer cells to HDAC inhibitors has been associated with a multitude of molecular and biological effects, ranging from transcriptional control, chromatin plasticity, protein-DNA interaction to cellular differentiation, growth arrest and apoptosis. In addition to the antitumor effects seen with HDAC inhibitors alone, these compounds may also potentiate cytotoxic agents or synergize with other targeted anticancer agents. The exact mechanism by which HDAC inhibitors cause cell death is still unclear and the specific roles of individual HDAC enzymes as therapeutic targets has not been established. However, emerging evidence suggests that the effects of HDAC inhibitors on tumor cells may not only depend on the specificity and selectivity of the HDAC inhibitor, but also on the expression patterns of HDAC enzymes in the tumor tissue. In this review, the recent advances in the understanding and clinical development of HDAC inhibitors, as well as their current role in cancer therapy, will be discussed.

Histone deacetylase inhibitor suppresses virus-induced proinflammatory responses and type 1 diabetes

Microbial infections are hypothesized to play a key role in the mechanism leading to type 1 diabetes (T1D). We used the LEW1.WR1 rat model of Kilham rat virus (KRV)-induced islet destruction to better understand how virus infection triggers T1D. Inoculation of the LEW1.WR1 rat with KRV results in systemic inflammation followed by insulitis and islet destruction 2-4 weeks post-infection. In this study, we evaluated the effect of treatment with the anti-inflammatory histone deacetylase inhibitor (HDACi) ITF-2357 on KRV-induced immunity and disease progression. Administering LEW1.WR1 rats with KRV plus ITF-2357 on 14 consecutive days beginning on the day of infection protected animals from islet infiltration and T1D. ITF-2357 reversed KRV-induced T and B cell accumulation in the spleen or pancreatic lymph nodes on day 5 following infection. Moreover, ITF-2357 reduced the expression level of KRV-induced p40 subunit of IL-12/IL-23 in spleen cells in vitro and in the peripheral blood in vivo. ITF-2357 suppressed the KRV-induced expression of transcripts for IRF-7 in the rat INS-1 beta cell line. ITF-2357 increased the virus-induced IL-6 gene expression in the spleen, but did not alter the ability of LEW1.WR1 rats to develop normal KRV-specific humoral and cellular immune responses and clear the virus from the pancreatic lymph nodes, spleen, and serum. Finally, ITF-2357 reversed virus-induced modulation of bacterial communities in the intestine early following infection. The data suggest that targeting innate immune pathways with inhibitors of HDAC might represent an efficient therapeutic strategy for preventing T1D.

KEY MESSAGE

Microbial infections have been implicated in triggering type 1 diabetes in humans and animal models. The LEW1.WR1 rat develops inflammation and T1D following infection with Kilham rat virus. The histone deacetylase inhibitor ITF-2357 suppresses virus-induced inflammation and prevents diabetes. ITF-2357 prevents T1D without altering virus-specific adaptive immunity or virus clearance. ITF-2357 therapy may be an efficient approach to prevent T1D in genetically susceptible individuals.

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.

Valproic acid ameliorates inflammation in experimental autoimmune encephalomyelitis rats

Valproic acid (VPA) is a short-chain branched fatty acid with anti-inflammatory, neuro-protective and axon remodeling effects. Here we have studied effects of VPA in gpMBP(68-84)-induced experimental autoimmune encephalomyelitis (EAE). Both preventive (from Day 0 to Day 18) and therapeutic (from Day 7 to Day 18 or from Day 9 to Day 19) VPA (500 mg/kg, intra-gastric) administration to EAE rats once daily greatly reduced the severity and duration of EAE, and suppressed mRNA levels of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-17, matrix metalloproteinase 9 (MMP9), inducible nitric oxide synthase (iNOS) and transcription factor T-bet, but increased levels of IL-4 mRNA in EAE spinal cords. Furthermore, preventive VPA treatment greatly attenuated accumulation of macrophages and lymphocytes in EAE spinal cords. VPA treatment altered the cytokine milieu of lymph nodes, modulating the Th profile from Th1 and Th17 to a profile of Th2 and regulatory T cells. In addition, in vitro study showed that VPA inhibited non-specific lymphocyte proliferation in a dose-dependent manner. In summary, our data demonstrated that VPA could suppress systemic and local inflammation to improve outcome of EAE, suggesting that VPA might be a candidate for treatment of multiple sclerosis.

Why do anti-inflammatory therapies fail to improve insulin sensitivity?

Chronic inflammation occurs in obese conditions in both humans and animals. It also contributes to the pathogenesis of type 2 diabetes (T2D) through insulin resistance, a status in which the body loses its ability to respond to insulin. Inflammation impairs insulin signaling through the functional inhibition of IRS-1 and PPARγ. Insulin sensitizers (such as rosiglitazone and pioglitazone) inhibit inflammation while improving insulin sensitivity. Therefore, anti-inflammatory agents have been suggested as a treatment strategy for insulin resistance. This strategy has been tested in laboratory studies and clinical trials for more than 10 years; however, no significant progress has been made in any of the model systems. This status has led us to re-evaluate the biological significance of chronic inflammation in obesity. Recent studies have consistently asserted that obesity-associated inflammation helps to maintain insulin sensitivity. Inflammation stimulates local adipose tissue remodeling and promotes systemic energy expenditure. We propose that these beneficial activities of inflammation provide an underlying mechanism for the failure of anti-inflammatory therapy in the treatment of insulin resistance. Current literature will be reviewed in this article to present evidence that supports this viewpoint.

Nanotechnology use with cosmeceuticals

The skin is a complex organ and its aging is a complex process. Cutaneous aging is influenced by factors such as sun exposure, genetics, stress and the environment. While skin laxity, rhytides, and dyschromia appear on the surface, these processes originate in deeper layers including the dermis and subcutaneous tissues. Until recently, most topical skin treatments were applied to, and consequently only affected the skin surface. Skin care has evolved to be scientifically based, and as knowledge increases about the physiology of the skin, novel methods of maintaining its health and appearance are developed. New generation skin care products are targeting multiple aging mechanisms by utilizing functional active ingredients in combination with innovative delivery systems.

Neuroinflammation in Huntington's disease

Huntington's disease (HD) is a monogenic neurodegenerative disease characterized by abnormal motor movements, personality changes and early death. In contrast to other neurodegenerative diseases, very little is known about the role of neuroinflammation in HD. While the current data clearly demonstrate the existence of inflammatory processes in HD pathophysiology, the question of whether neuroinflammation is purely reactive or might actively participate in disease pathogenesis is currently a matter of ongoing research and debate. This review will try to shed some light on the current state of research in this area and provide an outlook on potential future developments.

Protective effect of suberoylanilide hydroxamic acid against LPS-induced septic shock in rodents

We have recently found that suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, improves survival in a lethal model of hemorrhagic shock in rats. The purpose of the present study was to determine whether SAHA treatment would prevent LPS-induced septic shock and improve the survival in a murine model. C57BL/6J mice were randomly divided into two groups. Experimental mice were given intraperitoneal SAHA (50 mg/kg) in vehicle dimethyl sulfoxide fluid (n = 10). The control mice (n = 10) received vehicle dimethyl sulfoxide only. They were injected with LPS (20 mg/kg, i.p.) 2 h later, and the animals from the treatment group were given a second dose of SAHA. Survival was monitored during the next 7 days. In a parallel study, mice treated with or without SAHA were subjected to LPS insult while normal (sham) mice serviced as controls. 1) Lungs were harvested at 3 and 48 h for analysis of gene expression and pathologic changes, respectively; 2) spleens were isolated for analysis of neutrophilic cell population. In addition, RAW264.7 mouse macrophages were cultured to assess the effects of SAHA on LPS-induced inflammation in vitro. All mice in the control group that were subjected to LPS challenge died in less than 48 h. However, SAHA-treated animals displayed a significantly higher 1-week survival rate (87.5%) compared with the control group (0%). Moreover, LPS insult decreased the acetylation of histone proteins (H2A, H2B, and H3), elevated the levels of TNF-alpha in vivo (circulation) and in vitro (culture medium), increased the neutrophilic cell population in the spleen, enhanced the expression of TNF-alpha and IL-1beta genes in lung tissue, and augmented the pulmonary neutrophil infiltration. In contrast, SAHA treatment markedly attenuated all of these LPS-induced alterations. We report for the first time that administration of SAHA (50 mg/kg) significantly attenuates a variety of inflammatory markers and improves long-term survival after a lethal LPS insult.

Hypoxic "second hit" in leukocytes from trauma patients: Modulation of the immune response by histone deacetylase inhibition

INTRODUCTION

Histone deacetylase inhibitors (HDACI), can improve survival after lethal hemorrhagic shock, and modulate the inflammatory response after hemorrhage/lipopolysaccharide (LPS). The current experiments were designed to study the effects of HDACI after hemorrhage and severe hypoxia.

METHODS

Splenic leukocytes from trauma and non-trauma patients (n=4-5/group) were exposed to severe hypoxia with/without suberoylanilide hydroxamic acid (SAHA, 400 nM) for 8h. Cytokines were measured by ELISA and RT-PCR, and hypoxia inducible factor (HIF)-1a and heme oxygenase (HO)-1 by Western blot.

RESULTS

After hemorrhage and hypoxia, SAHA increased IL-1b gene (4.7+/-1.2-fold) and protein expression (2.1+/-0.6-fold) in trauma splenic leukocytes. It also reduced IL-10 gene expression (0.6+/-0.2-fold), but did not alter TNFa or IL-6 levels. This unexpected pro-inflammatory response may be due to a decrease in HIF-1a and HO-1 protein levels.

CONCLUSIONS

In this model of severe hypoxia, treatment with SAHA increased the inflammatory response in trauma leukocytes, possibly through inhibition of the HIF-1/HO-1 pathway. Splenic leukocytes from non-trauma patients were variably affected by SAHA. Taken in context with the known anti-inflammatory properties of HDACI after hemorrhage/LPS, these findings suggest that the immune-modulating functions of HDACI are dependent on the type and severity of both the priming injury and subsequent insult.