Histone Deacetylase Research Articles

Abstract C051: Epigenetic reprogramming of brain-infiltrating myeloid cells deters brain metastasis outgrowth

Abstract The unique brain immune microenvironment (BrIME) co-evolves with brain metastasis (BrM) and is marked by immune suppression, posing a significant therapeutic challenge. BrIME is dominated by myeloid cells, with monocyte-derived macrophages (MDMs) comprising nearly half of the tumor-infiltrating leukocytes. Targeting MDMs remains challenging due to their inherent heterogeneity and high plasticity, which are regulated by epigenetic modifiers, including histone deacetylases (HDACs). Yet, the impact of HDAC inhibition in BrIME and its implications for BrM immunotherapy remains unclear. Here, we establish BrM syngenetic model by intracarotid artery (ICA) injection. Immune profiling by mass cytometry (CyTOF) analysis shows that selective class I HDAC inhibitor (HDACi) Entinostat (ENT) significantly enriches inflammatory MDMs in E0771 murine mammary tumor BrM model. Additionally, functional assay with bone marrow-derived macrophages (BMDMs) shows that ENT significantly enhances tumor cell phagocytosis and antigen presentation, increasing the proliferation of antigen-specific T cells in vitro. To test whether HDAC inhibition enhances antitumoral response in the BrIME, we designed a novel sequential treatment: with (1) ENT pre-conditioning the BrIME, (2) low- dose whole brain radiotherapy (LD-WBRT) to release tumor antigen followed by (3) anti-PD1 immune checkpoint therapy (ICT) to reinvigorate tumor-infiltrating. Our result shows that sequential triple treatment demonstrates significant BrM deterrence and induce a specific interferon-responsive MDM subset with robust type I interferon response in single-cell RNA sequencing, correlating with improved ICT clinical outcomes. Our data show that selective HDACi treatment reprograms the suppressive BrIME by steering the BrM-infiltrating MDMs toward immuno-stimulatory status. Sequential triple combinatorial therapy impedes BrM by activating innate and adaptive immunity simultaneously and is well tolerated in the animal model. Our findings highlight the potential of HDACi-mediated epigenetic reprogramming of the BrIME to enhance therapeutic efficacy in treating BrM. Citation Format: Shao-Ping Yang, Yimin Duan, Xiangliang Yuan, Lin Zhang, Wendao Liu, Jun Yao, Patrick Zhang, Jason T Huse, Zhongming Zhao, Dihua Yu. Epigenetic reprogramming of brain-infiltrating myeloid cells deters brain metastasis outgrowth [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C051.

Integrated proteomics and metabolomics analyses reveal new insights into the antitumor effects of valproic acid plus simvastatin combination in a prostate cancer xenograft model associated with downmodulation of YAP/TAZ signaling.

Despite advancements in therapeutic approaches, including taxane-based chemotherapy and androgen receptor-targeting agents, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable tumor, highlighting the need for novel strategies that can target the complexities of this disease and bypass the development of drug resistance mechanisms. We previously demonstrated the synergistic antitumor interaction of valproic acid (VPA), an antiepileptic agent with histone deacetylase inhibitory activity, with the lipid-lowering drug simvastatin (SIM). This combination sensitizes mCRPC cells to docetaxel treatment both in vitro and in vivo by targeting the cancer stem cell compartment via mevalonate pathway/YAP axis modulation. Here, using a combined proteomic and metabolomic/lipidomic approach, we characterized tumor samples derived from 22Rv1 mCRPC cell-xenografted mice treated with or without VPA/SIM and performed an in-depth bioinformatics analysis. We confirmed the specific impact of VPA/SIM on the Hippo-YAP signaling pathway, which is functionally related to the modulation of cancer-related extracellular matrix biology and metabolic reprogramming, providing further insights into the molecular mechanism of the antitumor effects of VPA/SIM. In this study, we present an in-depth exploration of the potential to repurpose two generic, safe drugs for mCRPC treatment, valproic acid (VPA) and simvastatin (SIM), which already show antitumor efficacy in combination, primarily affecting the cancer stem cell compartment via MVP/YAP axis modulation. Bioinformatics analysis of the LC‒MS/MS and 1H‒NMR metabolomics/lipidomics results confirmed the specific impact of VPA/SIM on Hippo-YAP.

Valproate Administration to Adult 5xFAD Mice Upregulates Expression of Neprilysin and Improves Olfaction and Memory.

It is well known that the development of neurodegeneration, and especially Alzheimer's disease (AD), is often accompanied by impaired olfaction which precedes memory loss. A neuropeptidase neprilysin (NEP)-a principal amyloid-degrading enzyme in the brain-was also shown to be involved in olfactory signalling. Previously we have demonstrated that 5xFAD mice develop olfactory deficit by the age of 6months which correlated with reduced NEP expression in the brain areas involved in olfactory signalling. The aim of this study was to analyse the effect of administration of a histone deacetylase inhibitor, valproic acid (VA), to adult 5xFAD mice on their olfaction and memory as well as on brain morphology and NEP expression in the parietal cortex (PC) and hippocampus (Hip). The data obtained demonstrated that administration of VA to 7-month-old mice (200mg/kg of body weight) for 28days resulted in improvement of their memory in the Morris water maze as well as olfaction in the odor preference and food search tests. This correlated with increased expression of NEP in the PC and Hip as well as a reduced number of amyloid plaques in these brain areas. This strongly suggests that NEP can be considered an important therapeutic target not only in AD but also in olfactory loss.

Identification of Potential Inhibitors of Histone Deacetylase 6 Through Virtual Screening and Molecular Dynamics Simulation Approach: Implications in Neurodegenerative Diseases

Background: Histone deacetylase 6 (HDAC6) plays a crucial role in neurological, inflammatory, and other diseases; thus, it has emerged as an important target for therapeutic intervention. To date, there are no FDA-approved HDAC6-targeting drugs, and most pipeline candidates suffer from poor target engagement, inadequate brain penetration, and low tolerability. There are a few HDAC6 clinical candidates for the treatment of mostly non-CNS cancers as their pharmacokinetic liabilities exclude them from targeting HDAC6-implicated neurological diseases, urging development to address these challenges. They also demonstrate off-target toxicity due to limited selectivity, leading to adverse effects in patients. Selective inhibitors have thus been the focus of development over the past decade, though no selective and potent HDAC6 inhibitor has yet been approved. Methods: This study involved an integrated virtual screening against HDAC6 using the DrugBank database to identify repurposed drugs capable of inhibiting HDAC6 activity. The primary assessment involved the determination of the ability of molecules to bind with HDAC6. Subsequently, interaction analyses and 500 ns molecular dynamics (MD) simulations followed by essential dynamics were carried out to study the conformational flexibility and stability of HDAC6 in the presence of the screened molecules, i.e., penfluridol and pimozide. Results: The virtual screening results pinpointed penfluridol and pimozide as potential repurposed drugs against HDAC6 based on their binding efficiency and appropriate drug profiles. The docking results indicate that penfluridol and pimozide share the same binding site as the reference inhibitor with HDAC6. The MD simulation results showed that stable protein–ligand complexes of penfluridol and pimozide with HDAC6 were formed. Additionally, MMPBSA analysis revealed favorable binding free energies for all HDAC6–ligand complexes, confirming the stability of their interactions. Conclusions: The study implies that both penfluridol and pimozide have strong and favorable binding with HDAC6, which supports the idea of repositioning these drugs for the management of neurodegenerative disorders. However, further in-depth studies are needed to explore their efficacy and safety in biological systems.

Discovery of novel and highly potent dual-targeting PKMYT1/HDAC2 inhibitors for hepatocellular carcinoma through structure-based virtual screening and biological evaluation

Simultaneous inhibition of two or more pathways is playing a crucial role in the treatment of hepatocellular carcinoma with complex and diverse pathogenesis. However, there have been no reports of dual-targeting inhibitors for protein kinase membrane-associated tyrosine/threonine 1 (PKMYT1) and histone deacetylase 2 (HDAC2), which are critical targets for hepatocellular carcinoma treatment. Here, an integrated strategy of virtual screening was utilized to identify dual-targeting inhibitors for PKMYT1 and HDAC2. Notably, PKHD-5 has been identified as a potent inhibitor that selectively targets both PKMYT1 and HDAC2 with nanomolar affinity. Molecular dynamics have confirmed the strong binding stability of PKHD-5 with PKMYT1 and HDAC2. Importantly, it displayed a notably lower IC50 against the HepG2/MDR cell line, underscoring its potential to surmount drug resistance, while exhibiting minimal toxicity towards the normal liver cell line L02. Additionally, PKHD-5 has demonstrated significant antitumor proliferation effects without significant toxicity. In summary, the results suggest that PKHD-5 is a promising candidate for further preclinical studies of hepatocellular carcinoma therapy.

The HDAC6 inhibitor AVS100 (SS208) induces a pro-inflammatory tumor microenvironment and potentiates immunotherapy.

Histone deacetylase 6 (HDAC6) inhibition is associated with an increased pro-inflammatory tumor microenvironment and antitumoral immune responses. Here, we show that the HDAC6 inhibitor AVS100 (SS208) had an antitumoral effect in SM1 melanoma and CT26 colon cancer models and increased the efficacy of anti-programmed cell death protein 1 treatment, leading to complete remission in melanoma and increased response in colon cancer. AVS100 treatment increased pro-inflammatory tumor-infiltrating macrophages and CD8 effector T cells with an inflammatory and T cell effector gene signature. Acquired T cell immunity and long-term protection were evidenced as increased immunodominant T cell clones after AVS100 treatment. Last, AVS100 showed no mutagenicity, toxicity, or adverse effects in preclinical good laboratory practice studies, part of the package that has led to US Food and Drug Administration clearance of an investigational new drug application for initiating clinical trials. This would be a first-in-human combination therapy of pembrolizumab with HDAC6 inhibition for locally advanced or metastatic solid tumors.

Sirtuin inhibitors reduce intracellular growth of M. tuberculosis in human macrophages via modulation of host cell immunity.

Host-directed therapies aiming to strengthen the body's immune system, represent an underexplored opportunity to improve treatment of tuberculosis (TB). We have previously shown in Mycobacterium tuberculosis (Mtb)-infection models and clinical trials that treatment with the histone deacetylase (HDAC) inhibitor, phenylbutyrate (PBA), can restore Mtb-induced impairment of antimicrobial responses and improve clinical outcomes in pulmonary TB. In this study, we evaluated the efficacy of different groups of HDAC inhibitors to reduce Mtb growth in human immune cells. A panel of 21 selected HDAC inhibitors with different specificities that are known to modulate infection or inflammation was tested using high-content live-cell imaging and analysis. Monocyte-derived macrophages or bulk peripheral blood cells (PBMCs) were infected with the green fluorescent protein (GFP)-expressing Mtb strains H37Ra or H37Rv and treated with HDAC inhibitors in the micromolar range in parallel with a combination of the first-line antibiotics, rifampicin, and isoniazid. Host cell viability in HDAC inhibitor treated cell cultures was monitored with Cytotox-red. Seven HDAC inhibitors were identified that reduced Mtb growth in macrophages > 45-75% compared to average 40% for PBA. The most effective compounds were inhibitors of the class III HDAC proteins, the sirtuins. While these compounds may exhibit their effects by improving macrophage function, one of the sirtuin inhibitors, tenovin, was also highly effective in extracellular killing of Mtb bacilli. Antimicrobial synergy testing using checkerboard assays revealed additive effects between selected sirtuin inhibitors and subinhibitory concentrations of rifampicin or isoniazid. A customized macrophage RNA array including 23 genes associated with cytokines, chemokines and inflammation, suggested that Mtb-infected macrophages are differentially modulated by the sirtuin inhibitors as compared to PBA. Altogether, these results demonstrated that sirtuin inhibitors may be further explored as promising host-directed compounds to support immune functions and reduce intracellular growth of Mtb in human cells.

Tasquinimod promotes the sensitivity of ovarian cancer cells to cisplatin by down-regulating the HDAC4/p21 pathway.

To investigate whether Tasquinimod can influence cisplatin resistance in drug-resistant ovarian cancer (OC) cell lines by regulating histone deacetylase 4 (HDAC4) or p21, we explored its effects on the cell cycle, and associated mechanisms. RT-PCR and Western blot analyses, flow cytometry, CCK8 assay, and immunofluorescence were utilized to investigate the effects of Tasquinimod on gene expression, cell cycle, apoptosis, viability, and protein levels in OC cells. The results showed that Tasquinimod inhibited cell viability and promoted apoptosis in SKOV3/DDP (cisplatin) and A2780/DDP cells more effectively than DDP alone. In combination with cisplatin, Tasquinimod further enhanced cell apoptosis and reduced cell viability in these cell lines, an effect that could be reversed following HDAC4 overexpression. Tasquinimod treatment down-regulated HDAC4, Bcl-2, and cyclin D1, and CDK4 expression and up-regulated the cleaved-Caspase-3, and p21 expression in SKOV3/DDP and A2780/ DDP cells. Additionally, Tasquinimod inhibited DDP resistance in OC/DDP cells. These effects were similarly observed in OC mouse models treated with Tasquinimod. In conclusion, Tasquinimod can improve OC cells' sensitivity to DDP by down-regulating the HDAC4/p21 axis, offering insights into potential strategies for overcoming cisplatin resistance in OC.

Exploring the impact of childhood maltreatment on epigenetic and brain-derived neurotrophic factor changes in bipolar disorder and healthy control.

Childhood maltreatment may be linked to epigenetics and brain-derived neurotrophic factor (BDNF) changes, which are mechanisms altered in several psychiatric conditions, including bipolar disorder (BD). However, the specific mechanisms connecting childhood maltreatment to the pathophysiology of BD remain unclear. The present study aims to examine the effects of childhood maltreatment on epigenetic and neurotrophic outcomes in BD patients and health controls. History of childhood maltreatment was obtained using the Childhood Trauma Questionnaire (CTQ) from 36 BD outpatients and 46 healthy subjects. DNA methyltransferase (DNMT) activity, HMTH3K9 activity, histone 3 lysine 9 tri-methylation (H3K9me3) levels, histone deacetylase (HDAC)1 levels, HDAC2 levels, histone 3 lysine 14 acetylation (H3K14ac) levels, and mRNA of BDNF were evaluated in peripheral blood mononuclear cells. Plasma BDNF levels were also measured. Total scores of CTQ, as well as the subscale scores of emotional abuse, sexual abuse, and emotional neglect, were predictive of changes in DNMT and HMTh3k9 activity, H3K9m3 levels, BDNF mRNA expression, and BDNF levels. These findings were observed in all our samples and, in some cases, among BD patients. Emotional abuse was the main childhood maltreatment subtype associated with epigenetic alterations in BD. Our results elucidate some mechanisms by which childhood maltreatment can alter epigenetic and neurotrophic markers. Especially in BD subjects, our results suggest childhood maltreatment per se is not a direct cause for epigenetic alterations. In another way, we suppose that the effect of childhood maltreatment could be cumulative and interact with other factors associated with the pathophysiology of BD.

Discovery of Novel 5-Cyano-3-phenylindole-Based LSD1/HDAC Dual Inhibitors for Colorectal Cancer Treatment.

The dual inhibition of histone lysine-specific demethylase 1 (LSD1) and histone deacetylase (HDAC) has emerged as a promising strategy for cancer therapy. In this study, we report the discovery of novel 5-cyano-3-phenylindole-based LSD1/HDAC dual inhibitors, evaluated through both in vitro and in vivo assays. Among these inhibitors, compound 20c was identified as particularly potent, exhibiting high inhibitory activity against LSD1 (IC50 = 39.0 nM) and HDAC1/2/3/6/8 (IC50 = 1.4, 1.0, 1.3, 2.9, and 16.0 nM, respectively). Compound 20c effectively modulated the expression of biomarkers associated with LSD1 and HDAC inhibition and demonstrated superior antiproliferative activity compared to SAHA and 4SC-202 across multiple colorectal cancer cell lines. Following pharmacokinetic studies, 20c was further assessed in HCT-116 and HT-29 xenograft mouse models. It demonstrated significantly enhanced antitumor efficacy compared to SAHA, without causing observable toxicity. These findings highlight the potential of LSD1/HDAC dual inhibitors for the treatment of malignant cancers.

Maternal exercise represses FGF21 via SIRT1 to improve the phenotypic transformation of vascular smooth muscle in hypertensive offspring.

Maternal exercise during pregnancy is widely recognized as an effective means of promoting cardiovascular health in offspring. Few studies have explored how maternal exercise impacts vascular function and phenotypic switching in hypertensive offspring, despite the known involvement of vascular structural and functional remodeling in hypertension pathogenesis. Research indicates a significant relationship between elevated blood pressure and fibroblast growth factor 21 (FGF21) levels. It remains unclear whether maternal exercise during pregnancy can improve vascular function in hypertensive offspring by regulating FGF21 and its underlying mechanisms. In this study, pregnant spontaneously hypertensive rats and Wistar-Kyoto rats were randomly assigned to either a sedentary or exercise group. The exercise group underwent weightless swimming exercise from gestation day 1 (GD1) to GD20. The aim was to investigate the epigenetic modifications mediated by histone deacetylase sirtuin 1 (SIRT1) during the fetal period and the phenotypic changes in the mesenteric arteries (MAs) of hypertensive offspring. We found that maternal exercise significantly improved vascular remodeling in hypertensive offspring. Specifically, maternal exercise upregulated SIRT1 expression, which led to decreased H3K9ac (histone H3 lysine 9 acetylation) in the promoter region of the FGF21 gene. This epigenetic modification resulted in the transcriptional downregulation of FGF21 in the MAs of hypertensive fetuses. These results suggest that maternal exercise may lower blood pressure in hypertensive offspring by regulating deacetylation of the FGF21 gene promoter region through SIRT1, thereby reversing phenotypic switching and vascular structural remodeling.

Effects of a novel HDAC6-selective inhibitor's radiosensitization on cancer cells.

The radiation sensitivity of tumor cells is a critical determinant of their therapeutic response to radiotherapy. Histone deacetylase 6 (HDAC6), beyond its known role in modulating tubulin acetylation and influencing cell motility, is also involved in the DNA damage response, potentially enhancing tumor cell radiosensitivity. Targeted HDAC6 inhibitors have shown substantial promise in preclinical studies aimed at increasing radiosensitivity and inhibiting cellular migration. A new HDAC inhibitor, named OXHA, was designed by substituting the phenyl cap of SAHA with an N,5-diphenyloxazole-2-carboxamide group. The inhibitory activity of OXHA was evaluated via in vitro enzymatic assays. Its effects on tumor cell migration and radiosensitization potential were assessed using scratch wound healing assays, micronucleus formation, and clonogenic survival assays. Enzymatic assays confirmed OXHA's selective inhibition of HDAC6. Compared to SAHA, OXHA significantly increased α-tubulin acetylation while minimally impacting histone H3 acetylation, indicating a high selectivity for HDAC6. In combination with X-ray irradiation, OXHA markedly impaired wound healing in A549 and HepG2 cells, enhanced micronucleus formation, and reduced clonogenic survival across multiple tumor lines. OXHA exhibits potent and selective HDAC6 inhibition, effectively impeding tumor cell migration and enhancing radiosensitivity across multiple cell lines. These findings suggest that OXHA has strong potential as a therapeutic strategy to improve radiotherapy efficacy.

The Impact of Alcohol-Induced Epigenetic Modifications in the Treatment of Alcohol use Disorders.

Alcohol use disorders are responsible for 5.9% of all death annually and 5.1% of the global disease burden. It has been suggested that alcohol abuse can modify gene expression through epigenetic processes, namely DNA and histone methylation, histone acetylation, and microRNA expression. The alcohol influence on epigenetic mechanisms leads to molecular adaptation of a wide number of brain circuits, including the hypothalamus-hypophysis-adrenal axis, the prefrontal cortex, the mesolimbic-dopamine pathways and the endogenous opioid pathways. Epigenetic regulation represents an important level of alcohol-induced molecular adaptation in the brain. It has been demonstrated that acute and chronic alcohol exposure can induce opposite modifications in epigenetic mechanisms: acute alcohol exposure increases histone acetylation, decreases histone methylation and inhibits DNA methyltransferase activity, while chronic alcohol exposure induces hypermethylation of DNA. Some studies investigated the chromatin status during the withdrawal period and the craving period and showed that craving was associated with low methylation status, while the withdrawal period was associated with elevated activity of histone deacetylase and decreased histone acetylation. Given the effects exerted by ethanol consumption on epigenetic mechanisms, chromatin structure modifiers, such as histone deacetylase inhibitors and DNA methyltransferase inhibitors, might represent a new potential strategy to treat alcohol use disorder. Further investigations on molecular modifications induced by ethanol might be helpful to develop new therapies for alcoholism and drug addiction targeting epigenetic processes.

Lactylation of Hdac1 regulated by Ldh prevents the pluripotent-to-2C state conversion.

Cellular metabolism regulates the pluripotency of embryonic stem cells (ESCs). Yet, how metabolism regulates the transition among different pluripotent states remains elusive. It has been shown that protein lactylation, which uses lactate, a metabolic product of glycolysis, as a substrate, plays a critical role in various biological events. Here we focused on that glycolysis regulates the conversion between ESCs and 2-cell-like cells (2CLCs) through protein lactylation. RNA-seq revealed the activation of 2-cell (2C) genes by suppression of Ldh. Stable isotope labeling by amino acids in cell culture (SILAC) coupled with lactylated peptide enrichment and quantitative mass spectrometric analysis was carried out to investigate the mechanism how protein lactylation regulates the pluripotent-to-2C transition. And we focused on Hdac1. Lactylation of Hdac1 required for silencing 2C genes was proved by quantitative reverse-transcription PCR (qRT-PCR), immunofluorescence (IF), Western blot and chimeric embryos. Chromatin immunoprecipitation coupled with sequencing (ChIP-seq) and in vitro deacetylation assay confirmed lactylation of Hdac1 promoting its binding at 2C genes and enhancing its deacetylase activity, thereby facilitating the removal of H3K27ac and the silencing of 2C genes. We found that inhibition or depletion of Ldha, the enzyme converting pyruvate to lactate, leads to the activation of 2C genes, as well as reduced global lactylation in ESCs. To investigate the mechanism how protein lactylation regulates the pluripotent-to-2C transition, quantitative lactylome analysis was performed, and 1716 lactylated proteins were identified. We then focused on Hdac1, a histone deacetylase involved in the silencing of 2C genes. Lactylation of Hdac1 promotes its binding at 2C genes and enhances its deacetylase activity, thus facilitating the removal of H3K27ac and the silencing of 2C genes. In summary, our study reveals a mechanistic link between cellular metabolism and pluripotency regulation through protein lactylation. Our research is the first time to reveal that quantitative lactylome analysis in mouse ESCs. We found that lactylated Hdac1 promotes its binding at 2C genes and enhances its deacetylase activity, thus facilitating the removal of H3K27ac and the silencing of 2C genes.

Autoimmune disease: a view of epigenetics and therapeutic targeting

Autoimmune diseases comprise a large group of conditions characterized by a complex pathogenesis and significant heterogeneity in their clinical manifestations. Advances in sequencing technology have revealed that in addition to genetic susceptibility, various epigenetic mechanisms including DNA methylation and histone modification play critical roles in disease development. The emerging field of epigenetics has provided new perspectives on the pathogenesis and development of autoimmune diseases. Aberrant epigenetic modifications can be used as biomarkers for disease diagnosis and prognosis. Exploration of human epigenetic profiles revealed that patients with autoimmune diseases exhibit markedly altered DNA methylation profiles compared with healthy individuals. Targeted cutting-edge epigenetic therapies are emerging. For example, DNA methylation inhibitors can rectify methylation dysregulation and relieve patients. Histone deacetylase inhibitors such as vorinostat can affect chromatin accessibility and further regulate gene expression, and have been used in treating hematological malignancies. Epigenetic therapies have opened new avenues for the precise treatment of autoimmune diseases and offer new opportunities for improved therapeutic outcomes. Our review can aid in comprehensively elucidation of the mechanisms of autoimmune diseases and development of new targeted therapies that ultimately benefit patients with these conditions.

Abstract 4120290: Sex-specific Impact of Early to Mid-gestational Testosterone Excess on Sheep Fetal and Adult Offspring Lungs

Using the translationally relevant sheep model of prenatal testosterone (T) excess, we previously reported intrauterine growth retardation (IUGR) in both sexes, adverse sex specific programming of fetal heart and cardiometabolic dysfunction in adult female offspring. Because of the intricate reciprocal relationship between the heart and lungs, we hypothesized that gestational T excess will have detrimental sex-specific effects on offspring lungs beginning as early as fetal life and extending into adulthood. Pregnant ewes were intramuscularly injected with 100 mg of testosterone propionate twice weekly from gestational days (GD) 30-90 (term 147 days) and offspring lungs were harvested at GD120, 30 days after cessation of T treatment; (n=4-7/group) and in adulthood (n=4-6/group) and processed for molecular and histological analyses. Data was analyzed by student T test within each sex and Cohen (d) effect size was calculated (Cohens d>0.8 represents large effect size. Lung collagen was significantly increased in T-male fetuses (TM) vs control males (CM) (p=0.01, d=1.99) that persisted into adulthood (TM vs CM: p=0.01, d=1.83). The effects of gestational T excess was evidenced as an increase in collagen only in the lungs of adult T-female fetuses (TF) relative to control females (CF) (p=0.003, d=2.38), but not during fetal life. Gestational T excess induced significant parallel increases in TUNEL positive nuclei/frame in TM fetuses relative to CM (n=3/group, p=0.01, d=3.35) persisting as a large magnitude increase of TUNEL positive nuclei/frame in adult TM (p=0.12, d=0.96). In TF females, apoptotic changes were not noted in fetal lungs but an increase of TUNEL positive nuclei/frame was evidenced in adult TF (p=0.08, d=1.14). At the molecular level prenatal T excess induced an increase in histone deacetylase 1 (HDAC1) expression in fetal TM vs CM (p=0.04, d=1.50), and decrease in HDAC1 in TF vs CF (p=0.10, d=1.09) suggestive of T-induced epigenetic alteration. Transcriptomic analysis of fetal lungs revealed upregulation of pathways associated with estrogen signaling and neuroactive ligand receptor interaction, and downregulation of pathways associated with protein processing in endoplasmic reticulum and antigen processing&presentation (unadjusted p< 0.05, log FC>1.5) in both sexes. Overall, early to mid-gestational exposure to testosterone adversely reprograms the lungs in sex specific fashion as early as fetal life extending into postnatal adult life.

The Impact of the Histone Deacetylase Inhibitor-Sodium Butyrate on Complement-Mediated Synapse Loss in a Rat Model of Neonatal Hypoxia-Ischemia.

Perinatal asphyxia is one of the most important causes of morbidity and mortality in newborns. One of the key pathogenic factors in hypoxic-ischemic (HI) brain injury is the inflammatory reaction including complement system activation. Over-activated complement stimulates cells to release inflammatory molecules and is involved in the post-ischemic degradation of synaptic connections. On the other hand, complement is also involved in regenerative processes. The histone deacetylase inhibitor (HDACi)-sodium butyrate (SB)-provides reduction of inflammation by decreasing the expression of the proinflammatory factors. The main purpose of this study was to examine the effect of SB treatment on complement activation and synapse elimination after HI. Neonatal HI was induced in Wistar rats pups by unilateral ligation of the common carotid artery followed by 60-min hypoxia (7.6% O2). SB (300mg/kg) was administered on a 5-day regimen. Our study has shown decreased levels of synapsin I, synaptophysin, and PSD-95 in the hypoxic-ischemic hemisphere, indicating synaptic loss after neonatal HI. Transmission electron microscopy revealed injury of the synaptic structures in the brain after HI. SB treatment increased the level of the synaptic proteins, improved tissue ultrastructure, and reduced degradation of the synapses. Neonatal HI induced mRNA expression of the complement C1q, C3, C5, and C9, and their receptors C3aR and C5aR. The effect of SB was different depending on the time after induction of hypoxic-ischemic damage. Our study demonstrated that neuroprotective effect of SB may be related to the modulation of complement activity after HI brain injury.

Dissecting the epigenetic orchestra of HDAC isoforms in breast cancer development: a review.

Epigenetic modulators have recently emerged as potential targets in cancer therapy. Breast cancer, the second leading cause of cancer-related deaths among women globally and the most common cancer in India, continues to have a low survival rate despite available treatments. This underscores the urgent need for more effective therapeutic strategies. Histone deacetylases (HDACs), a prominent class of epigenetic modulators, are frequently overexpressed in various cancers, including breast cancer, making them and their downstream pathways, a focus of current research, aiming to develop more effective and less invasive treatments that could help overcome chemoresistance and enhance patient outcomes. Despite the growing body of evidences, a comprehensive and consolidated review on molecular intricacy behind the HDAC-mediated epigenetic regulation of breast cancer is conspicuously absent. Therefore, this review aims to open doors for future research by exploring the evolving role of HDACs, their molecular mechanisms, and their potential as therapeutic targets in breast cancer treatment.

Abstract 4134148: Reduced BMPR2 in Monocytes De-represses HERV-K and Sustains Inflammation in Pulmonary Arterial Hypertension

Background&Rationale: Human endogenous retroviral (HERV) elements are embedded in 8% of our genome. They remain quiescent but can be transiently activated by viral infection to induce an interferon (IFN) response. In pulmonary arterial hypertension (PAH), HERV-K expression is elevated in myeloid cells, and thus can promote inflammation observed in pulmonary arteries (PAs) with progressive obstructive remodeling. PAH is linked to a mutation or a decrease in BMPR2 expression which our laboratory has recently shown in monocytes (MONO). HERVs are silenced by SUMOylated (S) TRIM28 (KAP1, a methylase) and SPEN (a histone deacetylase) factors that are also sequestered by the lnc RNA XIST which is increased in females to inactivate the extra X-chromosome. When TRIM28 is phosphorylated (P) by DNA-PK, it loses methylase activity and can act as a transcription factor. Hypothesis: Reduced BMPR2 in MONO results in DNA-PK mediated P-TRIM28 causing demethylation of XIST targets (X-related genes) and HERV-K thus increasing their expression. Competitive SPEN binding to the increased XIST also de-represses HERV-K . Approach: We used THP-1 MONOs with BMPR2 shRNA and induced pluripotent stem cell (i) MONOs derived from BMPR2 mutant PAH patients and assessed HERV-K , XIST , IFNs and related our findings to DNA-PK–P-TRIM28 and sequestration of SPEN. Results: XIST and HERV-K mRNA were significantly elevated in THP-1 MONOs with shBMPR2 vs. shControl and in PAH-iMONO vs. control iMONO based on gender. Reduced BMPR2 also increased IFN genes. These findings were consistent with nuclear DNA-PK and P-TRIM28 shown to bind in affinity purification mass spectrometry analysis. Bisulfite conversion assay demonstrated decreased methylation of HERV-K in BMPR2 -deficient MONOs attributed to a reduction in the methylase S-TRIM28. RNA-IP in THP-1 MONOs with shBMPR2 vs. shControl indicated increased binding of XIST with TRIM28 and SPEN, suggesting a competitive reduction in binding to HERV-K. Conclusions: Loss of BMPR2 increases XIST and HERV-K in MONO related to DNA-PK induced P-TRIM28 and reduced methylase S-TRIM28. Increased HERV-K may also be a function of the increase in XIST sequestering its deacetylase SPEN. These molecular features underlie a chronic HERV-K -IFN inflammatory response in PAH. They may explain the female predisposition to PAH, because the increase in XIST in females heightens the propensity to activate HERV-K -IFN signaling and chronic inflammation in PAs infiltrated by MONO.

Repurposing Plant-Based Histone Acetyltransferase Inhibitors: A Review of Novel Therapeutic Strategies Against Drug-Resistant Fungal Biofilms.

The rapid emergence of drug-resistant fungal strains necessitates the development of novel therapeutic approaches for battling biofilm-related infections. Biofilms, efflux pumps, and suppression of virulence traits in pathogenic yeasts are governed by epigenetic enzymes, namely, histone acetyltransferases (HATs) and histone deacetylases (HDACs). The review article is focused on the use of histone acetyltransferase inhibitors (HATi), a mechanism-based epidrug that inactivates the regular function of HATs. With an emphasis on specific plant-based HATi and their Structure-Activity Relationship (SAR), the review enumerates the extensive list of anticancer HATi that can be screened for antifungal activities. By repurposing these anticancer HATi, this approach may help generate broad-spectrum antifungal medications that highlight common biological pathways between fungus and cancer, possibly revolutionizing both treatment domains.