Histone deacetylases (HDAC) catalyze the removal of acetylation modifications on histones and non-histone proteins, which regulates gene expression and other cellular processes. HDAC inhibitors (HDACi), approved anti-cancer agents, emerge as a potential new therapy for heart diseases. Cardioprotective effects of HDACi are observed in many preclinical animal models of heart diseases. Genetic mouse models have been developed to understand the role of each HDAC in cardiac functions. Some of the findings are controversial. Here, we provide an overview of how HDACi and HDAC impact cardiac functions under physiological or pathological conditions. We focus on in vivo studies of zinc-dependent classical HDACs, emphasizing disease conditions involving cardiac hypertrophy, myocardial infarction (MI), ischemic reperfusion (I/R) injury, and heart failure. In particular, we review how non-biased omics studies can help our understanding of the mechanisms underlying the cardiac effects of HDACi and HDAC.

Epstein-Barr virus (EBV) is linked to lymphoma and epithelioma but lacks drugs specifically targeting EBV-positive tumors. BamHI A Rightward Transcript (BART) miRNAs are expressed in all EBV-positive tumors, suppressing both lytic infection and host cell apoptosis. We identified suberoylanilide hydroxamic acid (SAHA), an inhibitor of histone deacetylase enzymes, as an agent that suppresses BART promoter activity and transcription of BART miRNAs. SAHA treatment demonstrated a more pronounced inhibition of cell proliferation in EBV-positive cells compared to EBV-negative cells, affecting both p53 wild-type and mutant gastric epithelial cells. SAHA treatment enhanced lytic infection in wild-type EBV-infected cells, while also enhancing cell death in BZLF1-deficient EBV-infected cells. It reduced BART gene expression by 85% and increased the expression of proapoptotic factors targeted by BART miRNAs. These findings suggest that SAHA not only induces lytic infection but also leads to cell death by suppressing BART miRNA transcription and promoting the apoptotic program.

Protein misfolding and mislocalization are common to both familial and sporadic forms of amyotrophic lateral sclerosis (ALS). Maintaining proteostasis through induction of heat shock proteins (HSP) to increase chaperoning capacity is a rational therapeutic strategy in the treatment of ALS. However, the threshold for upregulating stress-inducible HSPs remains high in neurons, presenting a therapeutic obstacle. This study used mouse models expressing the ALS variants FUSR521G or SOD1G93A to follow up on previous work in cultured motor neurons showing varied effects of the HSP co-inducer, arimoclomol, and class I histone deacetylase (HDAC) inhibitors on HSP expression depending on the ALS variant being expressed. As in cultured neurons, neither expression of the transgene nor drug treatments induced expression of HSPs in cortex, spinal cord or muscle of FUSR521G mice, indicating suppression of the heat shock response. Nonetheless, arimoclomol, and RGFP963, restored performance on cognitive tests and improved cortical dendritic spine densities. In SOD1G93A mice, multiple HSPs were upregulated in hindlimb skeletal muscle, but not in lumbar spinal cord with the exception of HSPB1 associated with astrocytosis. Drug treatments improved contractile force but reduced the increase in HSPs in muscle rather than facilitating their expression. The data point to mechanisms other than amplification of the heat shock response underlying recovery of cognitive function in ALS-FUS mice by arimoclomol and class I HDAC inhibition and suggest potential benefits in counteracting cognitive impairment in ALS, frontotemporal dementia and related disorders.

OBJECTIVE: Inhibitors of histone deacetylases (iHDACs) are promising drugs for neurodegenerative diseases. We have evaluated the therapeutic potential of the new iHDAC LASSBio-1911 in Aβ oligomer (AβO) toxicity models and astrocytes, key players in neuroinflammation and Alzheimer\'s disease (AD).
METHODS: Astrocyte phenotype and synapse density were evaluated by flow cytometry, Western blotting, immunofluorescence and qPCR, in vitro and in mice. Cognitive function was evaluated by behavioural assays using a mouse model of intracerebroventricular infusion of AβO.
RESULTS: LASSBio-1911 modulates reactivity and synaptogenic potential of cultured astrocytes and improves synaptic markers in cultured neurons and in mice. It prevents AβO-triggered astrocytic reactivity in mice and enhances the neuroprotective potential of astrocytes. LASSBio-1911 improves behavioural performance and rescues synaptic and memory function in AβO-infused mice.
CONCLUSIONS: These results contribute to unveiling the mechanisms underlying astrocyte role in AD and provide the rationale for using astrocytes as targets to new drugs for AD.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal form of pancreatic cancer characterized by therapy resistance and early metastasis, resulting in a low survival rate. Histone deacetylase (HDAC) inhibitors showed potential for the treatment of hematological malignancies. In PDAC, the overexpression of HDAC 2 is associated with the epithelial-mesenchymal transition (EMT), principally accompanied by the downregulation of the epithelial marker E-cadherin and increased metastatic capacity. The effector cytokine transforming growth factor-β (TGF β) is known to be a major inducer of the EMT in PDAC, leading to high metastatic and invasive potential. In addition, the overexpression of HDAC 6 in PDAC is associated with reduced apoptosis. Here, we have demonstrated that a novel HDAC 2/6 inhibitor not only significantly increased E-cadherin expression in PANC-1 cells (5.5-fold) and in 3D PDAC co-culture spheroids (2.5-fold) but was also able to reverse the TGF-β-induced downregulation of E-cadherin expression. Moreover, our study indicates that the HDAC inhibitor mediated re-differentiation resulting in a significant inhibition of tumor cell invasion by approximately 60% compared to control. In particular, we have shown that the HDAC inhibitor induces both apoptosis (2-fold) and cell cycle arrest. In conclusion, the HDAC 2/6 inhibitor acts by suppressing invasion via upregulating E-cadherin mediated by HDAC 2 blockade and by inducing cell cycle arrest leading to apoptosis via HDAC 6 inhibition. These results suggest that the HDAC 2/6 inhibitor might represent a novel therapeutic strategy for the treatment of PDAC tumorigenesis and metastasis.

Microglia, resident immune cells in the central nervous system (CNS), play a critical role in maintaining CNS homeostasis. However, microglia activated in response to brain injury produce various inflammatory mediators, including nitric oxide (NO) and proinflammatory cytokines, leading to considerable neuronal damage. NO generated by inducible NO synthase (iNOS) rapidly reacts with superoxide to form a highly toxic product, peroxynitrite. Therefore, iNOS is considered to be a putative therapeutic target for cerebral ischemia. Here, we examined the effects of panobinostat (Pano), a histone deacetylase inhibitor, on lipopolysaccharide (LPS)-induced iNOS expression using rat immortalized microglia HAPI cells. Pano inhibited LPS-induced expression of iNOS mRNA and NO production in a dose-dependent manner; however, it had little effect on the LPS-induced activation of c-Jun N-terminal kinase (JNK) and p38 or nuclear translocation of nuclear factor-κB (NF-κB). The interferon-β (IFN-β)/signal transducer and activator of transcription (STAT) pathway is essential for LPS-induced iNOS expression in macrophages/microglia. We also examined the effects of Pano on LPS-induced IFN-β signaling. Pano markedly inhibited LPS-induced IFN-β expression and subsequent tyrosine phosphorylation of STAT1. However, the addition of IFN-β restored the decreased STAT1 phosphorylation but not the decreased iNOS expression. In addition, Pano inhibited the LPS-increased expression of octamer binding protein-2 and interferon regulatory factor 9 responsible for iNOS expression, but IFN-β addition also failed to restore the decreased expression of these factors. Thus, we conclude that the inhibitory effects of Pano are due not only to the inhibition of the IFN-β/STAT axis but also to the downregulation of other factors not involved in this axis.

Schistosomiasis is a neglected zoonotic parasitic disease. Currently, praziquantel is the drug of choice for the treatment of schistosomiasis, and is the only effective chemical for treatment of schistosomiasis japonica. Since its introduction in the 1970s, praziquantel has been used for large-scale chemotherapy of schistosomiasis for over 40 years. However, there have been reports pertaining to the resistance to praziquantel in schistosomes. Therefore, development of novel antischistosomal agents as alternatives of praziquantel, is of great need. Histone deacetylases and histone acetyltransferases have been recently reported to play critical roles in the growth, development and reproduction of schistosomes, and are considered as potential drug targets for the treatment of schistosomiasis. This review summarizes the latest advances of histone deacetylase and histone acetyltransferase inhibitors in the research on antischistosomal drugs, so as to provide insights into research and development of novelantischistosomal agents.
［摘要］ 血吸虫病是一种被忽视的人兽共患寄生虫病。目前, 吡喹酮是治疗血吸虫病的首选药物, 也是治疗日本血吸虫 病的唯一有效药物。自 20 世纪 70 年代问世以来, 吡喹酮已在大规模血吸虫病化疗中应用了 40 余年, 长期大规模使用导 致部分地区血吸虫对其产生了抗性, 因此迫切需要研发新型抗血吸虫药物作为候选替代药物。近期研究表明, 组蛋白去 乙酰化酶和组蛋白乙酰转移酶在血吸虫的生长发育以及繁殖等阶段中均起关键作用, 被认为是治疗血吸虫病的潜在药 物靶点。本文总结了组蛋白去乙酰化酶抑制剂与组蛋白乙酰转移酶抑制剂在抗血吸虫药物研究中的最新进展, 以期为 抗血吸虫新药的研发提供参考。.

Histone deacetylase (HDAC) serves as a critical molecular regulator in the pathobiology of various malignancies and have garnered attention as a viable target for therapeutic intervention. A variety of HDAC inhibitors (HDACis) have been developed to target HDACs. Many preclinical studies have conclusively demonstrated the antitumor effects of HDACis, whether used as monotherapy or in combination treatments. On this basis, researchers have conducted various clinical studies to evaluate the potential of selective and pan-HDACis in clinical settings. In our work, we extensively summarized and organized current clinical trials, providing a comprehensive overview of the current clinical advancements in targeting HDAC therapy. Furthermore, we engaged in discussions about several clinical trials that did not yield positive outcomes, analyzing the factors that led to their lack of anticipated therapeutic effectiveness. Apart from the experimental design factors, issues such as toxicological side effects, tumor heterogeneity, and unexpected off-target effects also contributed to these less-than-expected results. These challenges have naturally become significant barriers to the application of HDACis. Despite these challenges, we believe that advancements in HDACi research and improvements in combination therapies will pave the way or lead to a broad and hopeful future in the treatment of solid tumors.

Neuropathic pain remains a formidable challenge for modern medicine. The first-line pharmacological therapies exhibit limited efficacy and unfavorable side effect profiles, highlighting an unmet need for effective therapeutic medications. The past decades have witnessed an explosion in efforts to translate epigenetic concepts into pain therapy and shed light on epigenetics as a promising avenue for pain research. Recently, the aberrant activity of histone deacetylase (HDAC) has emerged as a key mechanism contributing to the development and maintenance of neuropathic pain.
In this review, we highlight the distinctive role of specific HDAC subtypes in a cell-specific manner in pain nociception, and outline the recent experimental evidence supporting the therapeutic potential of HDACi in neuropathic pain.
We have summarized studies of HDAC in neuropathic pain in Pubmed.
HDACs, widely distributed in the neuronal and non-neuronal cells of the dorsal root ganglion and spinal cord, regulate gene expression by deacetylation of histone or non-histone proteins and involving in increased neuronal excitability and neuroinflammation, thus promoting peripheral and central sensitization. Importantly, pharmacological manipulation of aberrant acetylation using HDAC-targeted inhibitors (HDACi) has shown promising pain-relieving properties in various preclinical models of neuropathic pain. Yet, many of which exhibit low-specificity that may induce off-target toxicities, underscoring the necessity for the development of isoform-selective HDACi in pain management.
Abnormally elevated HDACs promote neuronal excitability and neuroinflammation by epigenetically modulating pivotal gene expression in neuronal and immune cells, contributing to peripheral and central sensitization in the progression of neuropathic pain, and HDACi showed significant efficacy and great potential for alleviating neuropathic pain.

BACKGROUND: Being implicated during tumor migration, invasion, clonogenicity, and proliferation, the nicotinamide adenine dinucleotide (NAD)/-phosphate (NADP)-dependent dehydrogenase/reductase member 2 (DHRS2) has been considered to be induced upon inhibition of histone deacetylases (HDACi). In this study, we evaluated the current knowledge on the underlying mechanisms of the (epi)genetic regulation of DHRS2, as well as its function during tumor progression.
METHODS: DHRS2 expression was evaluated on mRNA- and protein-level upon treatment with HDACi by means of qRT-PCR and western blot analyses, respectively. Re-analysis of RNA-sequencing data gained insight into expression of specific DHRS2 isoforms, while re-analysis of ATAC-sequencing data shed light on the chromatin accessibility at the DHRS2 locus. Further examination of the energy and lipid metabolism of HDACi-treated urologic tumor cells was performed using liquid chromatography-mass spectrometry.
RESULTS: Enhanced DHRS2 expression levels upon HDACi treatment were directly linked to an enhanced chromatin accessibility at the DHRS2 locus. Particularly the DHRS2 ENST00000250383.11 protein-coding isoform was increased upon HDACi treatment. Application of the HDACi quisinostat only mildly influenced the energy metabolism of urologic tumor cells, though, the analysis of the lipid metabolism showed diminished sphingosine levels, as well as decreased S1P levels. Also the ratios of S1P/sphingosine and S1P/ceramides were reduced in all four quisinostat-treated urologic tumor cells.
CONCLUSIONS: With the emphasis on urologic malignancies (testicular germ cell tumors, urothelial, prostate, and renal cell carcinoma), this study concluded that elevated DHRS2 levels are indicative of a successful HDACi treatment and, thereby offering a novel putative predictive biomarker.